最新刊期
卷 52 ， 期 5 ， 2020
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Development Characteristics of Landslide Hazards in Three-rivers Basin of Southeast Tibetan Plateau AI导读
摘要：Three-rivers basin, which spans the deeply incised southeast Tibetan Plateau and north Tibetan Plateau with a low relief surface, is characterized by highly varied topography and climate, strong neotectonic movement and frequent seismicity, leading to fragile geological conditions, frequent occurrence of geohazards, and resulting in remarkable hazard chains. This severely threatens the safety of local residents and engineering constructions, and normal operation of infrastructures. Based on the landslide hazards interpreted from GoogleEarth, the characteristics of landslide hazards in Three-rivers basin were analyzed. The GoogleEarth images were adopted to map the types and spatial distributions of landslide hazards. The results were verified with limited field reconnaissance. The SRTM digital elevation model (DEM) data with a resolution of 90 m were used to analyze the terrain parameters, including elevation, slope angle, slope aspect, and relative relief. The lithological groups were compiled from 1∶500000-scale geological maps based on detailed lithological descriptions. The grid layer of distances to major faults was buffered from the main faults of 1∶500000-scale geological maps, compiled with the major faults obtained from 1∶1500000-scale tectonic map of Tibetan Plateau and neighboring region, in which the tectonic units were also extracted. All vector layers were rasterized and reclassified together with the raster layers, and then overlaid with the spatial distribution of landslide hazards. Percentage of landslide area (PLA) was used to create histograms and statistically analyze the significance of the factors influencing the occurrence of landslide hazards, based on geographic information system (GIS) method. A total of 60 315 landslides with an area of not less than 0.001 km2 for single landslide, including slides, rockfalls and deforming bodies, were mapped in the Three-river basins with an area of about 462 000 km2. Landslide hazards were mostly slides in type, accounting for 97.73% of the total, and characterized by banded densely distribution along the deeply incised valleys with local differentiation, and densely distribution along some major faults, e.g. Batang fault, Weixi—Qiaohou fault, and Lawa—Wangdalong segment of Suwalong—Xiongsong fault. For terrain parameters, landslide hazards mostly occurred on the slopes with angle ranging from 20° to 30°, elevation varying from 800 m to 4 000 m, and local relief exceeding 1 000 m. Among the 18 lithological groups, the following 5 groups, clastic rock and slate intercalated with limestone, mudstone and shale and siltstone, ophiolitic mélange, phyllite and slate, volcanic rocks, were mostly prone to slope failure. Among the 25 tectonic units, the following 7 units, including Jinsha River ophiolitic mélange, Zhongza limestone terrane, Yanyuan—Lijiang Continental margin rift basin, Naqu—Luonong forearc basin, north Lancang River ophiolitic mélange, Baoshan Terrestrial sea basin, and Ganzi—Litang ophiolitic mélange, were more vulnerable to landslide hazards. Although slope aspect and distance to major faults might have some influences on the landslide hazards, the role was not significant. Landslide hazards were densely distributed in Three-rivers basin of southeast Tibetan Plateau. The terrain and geological parameters significantly influencing the occurrence of landslide hazards consist of slope angle, elevation, relief, lithological group, and tectonic unit. Both slope aspect and distance to major faults have little impact on the landslide hazards.关键词：Tibetan Plateau;Three-rivers basin;landslide hazard;landslide type;spatial distribution;influencing factors- 2945
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发布时间：2024-01-08 - 摘要：Territory of Three-parallel-rivers composing by Nu River, Lantsang River and Jinsha River in Tibet Plateau is a key zone for the study of the geological environment and nature resource development of Tibet Plateau. The investigation of active landslides in full coverage, the study of their development and distribution rule not only play an important role in slope disaster reduction and prevention, but also in geological science research. Take the 179 000 km2 study area of the Pan-three-river parallel catchment as an example. It is demonstrated the workflow and key technologies of the whole process: InSAR big data processing → landslide interpretation → development law analysis → key sections analysis, obtained active landslide data under 4 000 asl of medium-small scale in study area. The research results showed that, 1) The existing SAR data sources, InSAR technology and interpretation methods could meet the needs of small and medium-sized large-area landslide identification, and the time was ripe for complete InSAR recognitions of landslides in China; 2) The "phase resonance enhanced InSAR" (PRE-InSAR) technology designed for the rapid calculation of large redundant SAR observations could eliminate most of the adverse interference conditions, highlight the location, range and activity intensity of landslides, and effectively completed the InSAR data processing suitable for large-area landslide identification, which had the potential of popularization in technology; 3) Geomorphology and optical remote sensing images, and considering the formation and lithology, geohazard mechanism, triggering factors, combing 10 classes geomorphic development locations; 4) A total of 904 active landslides under 4 000 asl were interpreted, and they were mainly distributed in eight sections of three-river, namely, Wangbudui—Paoluo, Songxiong, Zhongzunong of Jinsha River; Basu of Nu River; Chaya, Chaya—Deqin and Huangdeng Reservoir of Lantsang River; 5) Active landslides are mainly the revival of ancient (old) landslides. It was revealed that the main environmental factors that had great influences on active landslides were river erosion, topographic slope, stratigraphic lithology, rainfall and temperature in order, while the spatial distribution of active structure and earthquake was not significant. The mutual feed between landslides and human activity was a major characteristic of the development of landslides in this region; 6) InSAR identification results more comprehensive and objective in reflecting the rules of the natural development of landslide, deepened to the understanding of the three-river region geohazard, could provide important support for the active landslide prevention & control of Tibet Plateau, but InSAR observation and interpretation had multiple solutions of active landslides. The next step is to develop a standardized InSAR identification workflow and conduct multi-source data fusion observation.关键词：Tibet Plateau;pan Three-parallel-rivers Territory;InSAR;active landslide;landslide recognition;development rule
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发布时间：2024-01-08 - 摘要：Large rock avalanche is the most devastating landslide type in the world. The southeastern Qinghai–Tibet Plateau is one of the most susceptible areas to large rock avalanche in the world. The slope failure in source area is the premise of large-scale high-speed and long-distance landslides. It is not only the basis of studying the long-distance mechanism of such landslides, but also the premise of preventing such landslides. To explore initial failure conditions of rock avalanches in the area, source slopes’ characteristics of 15 cases were analyzed with focusing on topographical and geological conditions, failure modes and trigger factors based on site investigation, satellite image analysis and unmanned aerial vehicle survey. It was found that: 1) runouts of the rock avalanches depended strongly on heights of source slopes and their drop heights with minimum slope height of 150 m, drop height of 100 m and slope angle of 30° ; 2) rock mass prone to rock avalanches were massive granite, basalt, and bedded limestone, sandy slate, slate and gneiss, all of which were either very competent or competent rocks with brittle failure natures, and of which occurrence of bedded rocks were either steeply dip slope, obliquely dip slope or reversely dip slope; 3) all of the source slopes’ failure were controlled strongly by discontinuities, including dip-slope, reverse dip-slope and obliquely joints as well as bedding planes. Field observation and joint survey revealed that five kinds of initial failure modes commonly occurred in those rock avalanches’ source slopes, specifically compound wedge slide, compound planar slide, flexural slide, toppling fall and buckling slide; 4) although it was common that some rock avalanches occurred with no specific trigger, earthquake was primary trigger of most rock avalanches, followed by glacier melting, both of which agitated those rock avalanches’ extremely rapid motion and exceptional long runout. Combining failure modes, rock mass type, slope structure, controlling discontinuities and driving forces, initial failure of rock avalanches’ source slopes in southeastern Qinghai–Tibet Plateau could be categorized into different groups in terms of geomechanics, including compound wedge slide or planar slide of massive rock slopes driven by gravity or plus earthquake, or pore water pressure, compound wedge slide or planar slide of obliquely dip bedded rock slope driven by gravity or plus earthquake, toppling fall or flexural slide of reversely dip bedded rock driven by gravity or plus earthquake, and buckling slide of steeply dip slope bedding rock driven by gravity or plus earthquake. The superposition of seismic ejection and the above-mentioned model was also one of the main characteristics of high-speed and long-distance landslides in this area.关键词：large rock avalanche;rock type;slope structure;controlling discontinuity;initial failure mode
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发布时间：2024-01-08 - 摘要：Large-scale damming landslides frequently occur in high-relief mountainous regions in the Tibetan Plateau where is characterized by active tectonics and intense fluvial incision, which commonly result in flood, landslide reactivation, and some other secondary disasters. Such favorable conditions for geohazards will severely affect the construction safety of vital projects of China, i.e., Sichuan-Tibet and Yunnan-Tibet Railways. However, general developing laws of landslide damming and simulation of whole process of disaster chain have not been properly accounted for in the Tibetan Plateau. It is essential to establish a database of landslide dammings in the Three–river–parallel Territory of the Tibetan Plateau for better obtaining the general laws. This study conducted detailed geological survey and mechanism analysis on landslides that have blocked valley river in the year of 2019, and periodically revealed the following conclusions: 1) suture and active fault not only altered the rock mass of hillslope and affect rock integrity and weathering extent, but also usually generated seismic events to trigger large landslides which slid rapidly and likely blocked rivers; 2) landslide dammings were prone to occur on the anaclinal hillslopes when river continuously eroded the concave bank, which would develop toppling deformations to a large-scale catastrophic landslide to block rivers; 3) anticline nucleus formed in the middle of a river valley commonly induced landslide damming by developing anaclinal hillslopes that would easily evolve into large landslide from toppling owing to the fragmented rock mass nearby the anticline; 4) chemical weathering of carbonaceous rock in the slope could facilitate the failure of large landslides. Large-scale rockslides would cause severe river blockage, flood and other disaster chain in mountainous region as long as the favorable geo-environment developed. Once the bedrock landslide blocked the river, the potential disaster chain problem would be serious. In the future, we need to further optimize and integrate resources, and overcome many difficulties in the investigation of landslide disasters in the Tibetan Plateau by means of high-tech methods. An understanding of general developing laws of landslide damming in the Three–river–parallel Territory can provide a conceptual model for our next work about the landslide database and is helpful to confront more challenges for disaster prevention and mitigation.关键词：Three–river–parallel Territory;damming landslide;developing law of landslide damming;challenges for disaster prevention
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发布时间：2024-01-08 - 摘要：The Qinghai-Tibet plateau has its unique geological background and complex geographical environment and landslide hazards in the plateau are well developed. Under complex tectonic dynamic action and the coupling action from the exogenic and endogenic geological processes, rock avalanches developed in Qinghai-Tibet plateau often have extremely high potential energy and migration displacement. This will cause serious damage to the structures and human activities within the range of influence. Therefore, the prevention and mitigation of serious landslides in Qinghai-Tibet plateau should be carried out in the whole process from the source area to the movement area, and the optimization design for treatment measures should be made according to the situation. In this study, the disposal measures, disaster reduction mechanism and application scope of severe landslides are discussed. According to the characteristics of the Qinghai-Tibet plateau, a high-lift siphon drainage system with variable diameters for landslides in high-altitude regions was developed. A new type of anti-slide pile structure which can resist large deformation of sliding body and a protective shed structure with shock-resistant and energy-absorbing characteristics. The Shanliangzi landslide in Jinsha hydropower station is selected as a case study. The results of indoor siphon drainage tests and four-point bending tests for concrete beam show that 1) with respect to different lifts, the drainage capacity of the siphon system with diameters of 4.0 mm+6.5 mm is obviously better than that with a diameter of 4.0 mm, and the variable diameter siphon system brings 64%～117% improvements in drainage capacity. 2) as the lift increases, the drainage capacity of the siphon system with a diameter of 6.5 mm decreases more quickly than that with 4.0 mm+6.5 mm, and the variable diameter siphon system brings 28%～42% reduction for the decline ratio of the drainage capacity with growth of the lift, and 3) compared with the traditional anti-slide pile, the new type of steel strand anti-slide pile not only improves the flexural strength, but also has better toughness, which can sustain more deformation without damage. The optimum design and comprehensive control measures from the slide source area to the movement area are carried out for the Shanliangzi landslide, which ensure the safe construction and long-term operation of Jinsha hydropower station.关键词：Qinghai-Tibet plateau;serious landslide;source slope;movement area;disaster prevention and mitigation technology
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发布时间：2024-01-08 -
Evolution of the Cracking Zones at the Site of the Baige Landslides and Their Future Development AI导读
摘要：The Baige “10·10” slide generated large volume of cracking zones outside the boundary of its source area, of which part slipped and caused the “11·3” slide. The extent of the cracking zones further developed after the “11·3” slide and there still exists great possibility of another landslide to occur and block the Jinsha River. Therefore, in 2019 landslide geology was further investigated and field instrumentation, such as borehole inclinometer and pore water pressure, was implemented in the cracking zones. The results indicate that: 1) the bedrock in the landslide area is mainly tectonic mélange of gneiss in the Jinsha Suture Belt, intermingled with carbonaceous slate, marble, and intruded ultrabasic and acid rocks. The bedrock alteration and weathering played important roles in the development of the slides. 2) The scope of the cracking zones has been developing from the occurrence of the “11·3” slide to June 2019. Zone C1 has extended about 500 m reaching the Baige Village, Zone C2 over the hill ridge for～130 m, while C3 remains basically unchanged. As for the magnitude of deformation, the “11·3” slide-triggered one is the largest, it then slows down. 3) In the cracking zones C1-1, C2 and C3-1, the shear bands at depth are well developed and their depth reached 18 m, 67 m and 22.5 m and their averaged deformation velocity is 20, 0.29 and 3.33 mm per day respectively. 4) No stable water table is observed in the cracking zones and the deformation is not well correlated with rainfall. 5) The deformation in the cracking zones is still developing without any sign of stop. Close attention should be paid to the zones C1-1 and C2-1 in the future, especially for the development of cracks and the disintegration of the rock lump at their toes.关键词：Baige landslides;cracking zone;evolution;field instrumentation;future development- 2199
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发布时间：2024-01-08 - 摘要：Toppling slope is a kind of special slope which has deformed, and may eventually develop into serious geological disasters such as landslide and collapse. The engineering geological characteristics of toppling slope is the basis of slope stability analysis and evaluation and treatment scheme design, At present, the relevant research work in China is not in-depth and systematic, which is difficult to meet the needs of engineering construction and geological disaster prevention and control in the new era. Zara hydropower station is planned to be built on Yuqu River, the first tributary of Nu River in the Qinghai-Tibet Plateau, and the slope toppling in the project area is generally developed, which has a great influence on the site selection and safe operation of the project. There are various types of soft rock and hard rock in the area, and the toppling mode is complete, which provides a representative engineering case for the relevant researches. It took several years from preliminary investigation, detailed investigation to special research to demonstrate in detail the engineering geological characteristics of the slope rock mass. Through the exploration and successful application of innovative technologies, the problems in the study of the engineering geological characteristics, such as the determination of the spatial scope of the toppling slope, the division of the engineering geological areas and the valuing of the shear strength parameters, were solved. By means of surveying and mapping, hole exploration, drilling, geophysical exploration, testing and testing, the scope of the slope was accurately defined, and the appropriate comprehensive exploration methods were proposed. Based on the rock mass structure and the type of deformation and failure, the dumped rock mass of the slope was divided into three areas, i.e., the layered bending area, fragmentation and tension area, and the area of falling and covering of loose bodies. Furthermore, the differences of occurrence, weathering characteristics, acoustic wave velocity and water permeability of rock strata at different areas were analyzed. According to the unique characteristics of the dump slope, a principle determining method of the shear strength of dump rock mass was proposed. The upper limit of value specified in the current standard was also properly extended. The mechanical mechanism of slope collapse is further improved by studying the process of slope collapse.关键词：toppling slope;space scope;toppling mechanism;engineering geological division;geological model;mechanical parameters
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发布时间：2024-01-08 -
Field Investigation and Analysis on Flood Disasters due to Baige Landslide Dam Break in Jinsha River AI导读
摘要：On October 10 and November 3, 2018, at the right bank of Jinsha River in Baige village, Boluo town, Jiangda County, Tibet autonomous region experienced two landslides and the consequent river blocking events, forming a huge landslide lake. The landslide dam broke after two disposal methods which are natural discharge and man-made excavation of the discharge channel. Among them, the second flooding due to the landslide dam break caused great damage to the roads, bridges, farmland and houses within the affected downstream areas of Tibet, Sichuan and Yunnan provinces. In order to deal with the unconventional and extraordinary flood threat of a similar large landslide dam break, and also for a relevant fundamental research, our research team conducted a field investigation on the disaster of flooding suffered by the Baige landslide dam break from December 21 to 29, 2018. The investigation started from the intersection of Baqu River and the Jinsha River in Batang County, the most severely affected area, and ended at Liyuan reservoir, where the flood threat basically disappeared. The total length of the investigation along Jinsha River is 488.6 km, and the focuses of field investigation are on the damage status of the houses, roads, bridges and water related infrastructures along the river banks. The maximum inundated water level or flood level marks due to the dam-break flooding, the water level during the investigation, the sediment accumulation on both sides of the Jinsha river and its sediment gradation, and the water level causing the damage of the bridges are analyzed accordingly. Valuable disaster-related data and results are obtained, which can provide a useful support for further theoretical studies of dam-break flooding.关键词：landslide dam;Baige;Jinsha River;flood due to dam break;disaster investigation- 2750
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发布时间：2024-01-08 - 摘要：Most of the landforms in southwest China are high mountains and valleys, which are prone to be dammed by the landslides and form dammed lakes. During the rising of water level, the encountered stress path is constant shear stress, namely, the shear stresses was constant, but the pore water pressures increased gradually. Currently, most of the conducted tests of landslide dam were focused on the consolidated drained or undrained tests, which is different from the actual stress path in the process of rising of water level. Therefore, the study on deformation characteristics of the landslide dam under the constant shear stress path is an effective way to deeply analyze the dynamic deformation of the landslide dam during the rising of water level. Hence, taking the Baige dammed lake on October 11, 2018 as an example, considered the height of landslide dam, the highest water level before overtopping and the actual stress path during rising of water level, the parametric studies were carried out based on the micro-scale DEM–PFV coupled simulation to investigate the deformation characteristics of landslide dam materials under different confining pressure, different initial stress ratio, and constant shear stress path. The deformation characteristics of landslide dam during the rising of water level and corresponding micromechanics were revealed according to the macro stress-strain relationship and the distribution of contact forces between particles. It suggests that the deformation characteristics of landslide dam materials during the rising of water level is highly dependent on the combined roles of location, strength, and extent of water level. At different locations, the confining pressure and stress ratio is different, and the maximal pore water pressure is different too. This induced different deformation characteristics during the rising of water level, and usually the deformation increased from the core of the landslide dam to the surface at upstream. At the same confining pressure, the materials closed to the side of landslide dam, the initial stress ratio is high, and the encountered pore water pressure is high, so it will be more easily deformed, and the extent of large deformation is restricted by the initial stress ratio and the final water level. This could be attributed to the weakening of contact forces between particles. At the internal part of landslide dam, the initial stress ratio is lower than that at the external part, hence the probability of passing the instability line is lower, and the deformation of the internal part is smaller.关键词：landslide dam;lake water level rising;discrete element method;numerical simulation;deformation characteristics
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发布时间：2024-01-08
CATASTROPHIC MECHANISMS AND RISK CONTROL OF MAJOR LANDSLIDES IN TIBETAN PLATEAU
- 摘要：The longitudinal reinforced earth-rock dam was a new type of dam. The dam structure was formed by setting the rigid impermeable core wall in earth-rock dam, that the rigid core-wall played an important role in anti-seepage water and soil pressure and resistance to deformation. The dam was divided into the upstream side and the downstream side by rigid core-wall, and the displacement of the wall and the water and soil load born by the wall changed with the water level on the upstream side. A transition between active and passive stress states was unlocked in the driven area of the upper and lower dam, which was segregated by rigid wall. Based on the Coulomb earth pressure theory and the safety definition of rigid core-wall bearing load that was proposed in this paper, the safety of rigid core-wall as the retaining wall bearing water and soil pressure was analyzed under three conditions of completion, normal water storage and sudden drawdown of water level, and the analytic formulas of safety in the three conditions were provided. On this basis, according to the relation between the wall safety and the dam stability the calculation method of the reduced coefficient of passive earth pressure was proposed. This calculation method considered the role that the rigid core-wall bored bidirectional water and soil pressure front and behind dam. The result showed that the stress conditions deformation and stability of the wall and the dam stability interrelated. The passive earth pressure loaded in the wall was unlocked with the increase of active pressure under normal water storage condition, and the coefficient of passive earth pressure was bigger than the other two conditions. The coefficient of passive earth pressure obtained by the calculation method in this paper was on the safe side, and the sectional shape of dam could be further optimized关键词：longitudinal reinforced earth-rock dam;stability of the dam;safety factor of core wall under earth pressure;the retaining wall working in two directions;passive pressure coefficient;optimization of earth-rock dam
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发布时间：2024-01-08 -
Experimental Study of the Multi-scales Riverbed Structure Change Based on SFM Topographic Survey AI导读
摘要：The variations of erosion or deposition of the riverbed caused by water and sediment movement are common phenomena in nature, which often cause practical engineering problems such as river sedimentation, river bed deformation, coastal retreat, and reservoir capacity reduction. These are closely related to the design, construction and operation of hydraulic projects. Therefore, it is of great significance to develop accurate and efficient methods of three dimensional riverbed terrains reconstruction and analyzing the volumes of erosion or deposition. In this paper, flume experiments with bed load sediment transport were conducted to study the river bed evolution under different flow conditions. The methods of Structure from Motion (SFM) were introduced in details, containing the shooting method, selection of GCPs, the establishment of river-channel mesh and the interpolation method. Based on the SFM method, three-dimensional terrain reconstructions of bed surface were carried out before and after scouring experiments to obtain the dense point clouds. On this basis, the same ground control points (GCPs) were fixed to acquire the actual three dimensional terrain coordinates, and then three dimensional point cloud coordinates were interpolated in the river bed mesh to accurately analyze erosional and depositional quantities of the entire bed. The results show that: 1) the volumes with or without the presence of block model were calculated by SFM respectively to verify that the relative error of the present method is less than 4%. 2) The variation qualities of erosion or deposition calculated by the SFM method and the qualities of the actual weighing were compared and the relative error of the present method is less than 5%. 3) This method was also applied to the large-scale river model experiment and the relative error is less than 10%. The results above show that present method can be applied to both flume experiment and larger river bed physical model experiment, to reconstruct the three-dimensional bed topography quickly and efficiently. The paper offers an innovative idea of studying bed evolution in hydraulic model experiments.关键词：scour and silting evolution;river model experiment;structure from motion;three-dimensional terrain reconstruction- 1868
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发布时间：2024-01-08 - 摘要：The filtration effect has an important effect on the diffusion of suspension permeation grouting. Filtration coefficient is the key parameter of permeation diffusion. Most of the existing studies assumed the coefficient as a constant, which had great limitations. Based on the mass conservation of each component, linear filtration law and homogeneous capillary model, the permeation diffusion equation of cement grout was established, using the particle deposition probability model to describe the filtered process of cement particles in porous media. Additionally, the determination method of model parameters was proposed. The 3D model test system of permeation grouting was developed. Using the model test system, the seepage grouting of sand with constant flow rate can be realized, and the multi-information in the grouting process can be collected. The model test of radial diffusion permeation grouting was carried out. The temporal and spatial variations of porosity and grout pressure were analyzed, combined with the theoretical model calculation results. The influences of grouting rate and water cement ratio on filtration mechanism were discussed, and the accuracy of theoretical calculation model was also verified. The results showed that the smaller the grouting rate, the bigger the porosity attenuation at the grouting hole, and the more severe the porosity attenuation along the slurry diffusion direction. The smaller the grout water-cement ratio, the faster the porosity attenuation and the more significant the filtration effect. Compared with the experimental results, the maximum calculation error of porosity and grouting pressure were less than 12% and 14.2%, respectively. The model can describe the radial diffusion process of cement slurry well.关键词：permeation grouting;deposition probability model;filtration effect;radial diffusion;cement grout
- 1999
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发布时间：2024-01-08 - 摘要：To determine a suitable shear test method of earthen based masonry along mortar joint, the effects of block type, horizontal mortar joint, load position and mortar joint material on the shear resistance of the masonry concrete along the joint were analyzed by conducting double shear tests on 48 different types of earthen based masonry. Based on the analytic hierarchy process, the different shear test methods were comprehensively evaluated, and a suitable method for the masonry of the earthen based masonry was determined. The results showed that the shear test method had a significant effect on the shear resistance of the masonry joints along the mortar joints. The shear strength of the specimens containing horizontal mortar joints was generally higher than that of the 3-brick specimens. The load position had a certain influence on the shear strength of the 6-brick specimen. The shear strength of the half-brick specimen was higher than that of the whole brick specimen in most cases. The bonding properties of special mortar with the block is preferably. The shear strengths of mortar specimens were 10~65 times that of slurry specimens. The 4-brick specimens showed significant advantages in terms of test operability and specimen stress state, and the comprehensive evaluation value was the highest, i.e., 0.32. The 4-brick shear test method was recommended as the shear test method of earthen based masonry along mortar joint.关键词：earthen based materials;masonry;shear strength;test method;analytic hierarchy process
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发布时间：2024-01-08 - 摘要：To study the seismic response of long-span bridges under the rotational ground motion, based on OpenSees, fifteen finite element models was built for one cable-stayed bridge considering the uncertainty of earthquake intensity and material parameters by using normal distribution Latin hypercube sampling method. A total of 15 groups of near-fault pulse ground motions were selected from the PEER ground motion database. Then, the rotational components of the ground motions were obtained from the seismic translational components based on the elastic wave theory. The dynamic response of the bridge was obtained through nonlinear dynamic time -history analysis. The damage indexes for the bridge components were proposed. The seismic fragility curves for the key components of the bridge were drawn based on the probabilistic demand analysis method. The results showed that the damage probability of the key components of the bridge would be significantly changed when the rotational ground motion was considered. The increase of the bridge damage probability was closely related to the bridge component type and damage direction. When the rotational ground motion was considered, the middle section of the tower has the highest sensitivity to the torsion component of ground motion. The damage probability of the tower under the ground motions with rotational component would be increased as much as 22.12% compared with that without considering rotational ground motion. The rotational ground motion also had a higher destructive effect on the bottom section of the tower and the bottom section of the side pier (in bridge transverse direction), with a damage probability increase of 17.33% and 19.45%, respectively. However, for the deck and its longitudinal restraint members, the damage probability of these members would be slightly reduced when the rotational ground motion was considered.关键词：cable-stayed bridge;seismic design of bridges;fragility curve;rotational ground motion;numerical simulation
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发布时间：2024-01-08 - 摘要：Flood disaster is one of the most serious natural disasters in China, and flood control of reservoirs is an important means to effectively avoid or mitigate flood disasters. Currently, flood control dispatching of reservoirs mainly uses optimization algorithm to obtain the optimal dispatching decision-making scheme, rarely considering the operation control of reservoir flood discharge facilities, which often leads to the deviation of the actual flood dispatching results from the optimal dispatching results. In this paper, by studying the digitalization of cascade reservoirs flood discharge facilities, the database of flood discharge facilities usage is established. Combining with the joint flood control model of cascade reservoirs, the joint control strategy of cascade reservoirs flood discharge facilities is studied. Taking the joint operation of cascade reservoirs flood discharge facilities in the lower reaches of Yalong River as an example, the discharge process of optimal dispatching scheme is more uniform than that of conventional dispatching, which greatly reduces the peak flow. For example, the variation range of discharge process of Jinping-I hydropower station is reduced from 1 712～5 375 m3/s to 3 181～3 713 m3/s, and the variation number is also reduced from 10 to 5, with the peak flow being reduced by 22%. At the same time, the total number of cascade reservoirs flood discharge facilities changes in the optimal dispatching scheme is significantly reduced from 182 to 153 times when compared with the conventional operation scheme, which shows that the frequency of flood discharge facilities combination scheme adjustment is significantly reduced. The research results have important theoretical significance and engineering practical value for promoting the refinement and intellectualization of cascade reservoirs flood control optimal operation to the operation control of flood discharge facilities.关键词：cascade reservoirs;digitalization of flood discharge facilities usage;joint flood control dispatching model;selection principle of combination scheme;joint regulation strategy
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发布时间：2024-01-08 - 摘要：In the seismic design of long-span continuous beam bridges in high intensity seismic area, isolation devices are generally used to reduce the seismic response and economic losses of structures, and different arrangements of isolation measures often determine the seismic performance and initial cost of structures. In order to comprehensively evaluate the rationality of seismic isolation design of continuous girder bridge from its anti-seismic and economic performance, a high-speed railway continuous girder bridge in the high-intensity seismic area was taken as the background. A variety of seismic isolation schemes were designed to carry out seismic vulnerability analysis, and the economics of each scheme during the whole life of the bridge was discussed based on the minimum life cycle cost criterion. The results show that the whole bridge could use the hyperbolic spherical isolation bearing and the viscous damper to minimize the earthquake loss during the whole life cycle, but the initial cost of the bridge was too high due to the cost of isolation measures, which led to the poor economy of this scheme. While, equipping the whole bridge with hyperboloid spherical isolation bearings and side piers with viscous dampers was the optimal scheme in the seismic isolation design of the bridge, which met the requirements of seismic fortification, greatly reduced the initial cost and achieved balance between the cost of structural isolation measures and expected loss of the bridge. Facing with the problem that the current bridge seismic isolation scheme designs were mainly considering the seismic performance of bridge but ignoring its economic benefits, the research method of bridge seismic isolation scheme presented in this paper realized the double objective evaluation of structural seismic performance and economic benefit, which would provide a new idea for stakeholders to make reasonable decision on bridge seismic isolation scheme.关键词：isolated bridge;IDA analysis;earthquake vulnerability analysis;earthquake loss;life cycle cost
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发布时间：2024-01-08 - 摘要：To study the dynamic parameter characteristics of the granular rubber-sand mixtures (a new type of subgrade filler) under cyclic train loading, the indoor consolidated undrained dynamic triaxial tests were carried out. The effect of granular rubber content, confining pressure and loading frequency on the shear modulus and damping ratio characteristics of the granular rubber-sand mixtures were studied. The results showed that when the shear strain was constant, the shear modulus decreased with the increase of granular rubber content or loading frequency, and increased with the increase of confining pressure. Based on the Hardin-Drnevichin hyperbolic law, the shear modulus test results were fitted to obtain the maximum shear modulus, which decreased with the increase of granular rubber content. When the shear strain was constant, the damping ratio of the granular rubber-sand mixtures increased with the increase of granular rubber content, and decreased with the increase of confining pressure. Based on the experimental results, the relationship between damping ratio and shear strain was established. In addition, based on the micro contact characteristics of flexible rubber particles and rigid sand particles, the influence mechanism of granular rubber on shear modulus and damping ratio of the mixtures was analyzed. According to the research results, the highest granular rubber content in the new subgrade filler was 20%. When the granular rubber content was lower than 20%, the new subgrade filler, whose dynamic shear modulus can meet the requirements and damping ratio was relatively large, had a good damping and energy dissipation effect.关键词：granular rubber-sand mixtures;new subgrade filler;shear modulus;damping ratio;granular rubber content
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发布时间：2024-01-08
HYDRAULIC & CIVIL ENGINEERING
- 摘要：Many applications in location-based services require multiple users to share location. However, the traditional rigid policy of privacy protection forces users to share and expose their precise locations. In order to meet the user’s personalized needs for privacy protection, a new multi-user location sharing privacy protection scheme was proposed in this paper. Two kinds of location conversion models were used in our solution to ensure that users can flexibly customize their shared locations with different precision levels. Then all the location data with different precisions is packaged and converted through a multi-secret sharing mechanism based on the Chinese Remaining Theorem. In this mechanism, only one time shares-distribution was needed to realize different shared objects recover location information with corresponding different accuracies. In the security analysis, it is proved that the flexible location privacy protection of multi-user location sharing was realized in an untrusted net environment by our solution. It is highly secure since it does not depend on the trustability of the location provider and can resist single location server attack, collusion attacks of multiple location servers and multiple users. Furthermore, compared with the peer solutions, the simulation experiments showed that ours is more efficient and stable in performance. When the number of location servers participating in the share storage increases or the higher-precision location information is required to be reconstructed, the overheads of computation and communication will not increase dramatically. Thus, it is also applicable in the resource-constrained network environment.关键词：multiple users location sharing;flexible location privacy protection;multi-secret sharing
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发布时间：2024-01-08 - 摘要：The previous NTRU-type multi-key fully homomorphic encryption (MKFHE) schemes were constructed over power-of-2 cyclotomic polynomial rings, and the complicated key-switching operations were used in the schemes to complete the fully homomorphic computation. They were suffered from the subfield attacks and had low evaluating efficiency. In this paper, an NTRU-type MKFHE scheme with better security and higher efficiency was proposed. Firstly, the prime cyclotomic polynomial ring was applied to the previous NTRU-type MKFHE schemes, and a NTRU-type MKFHE basic scheme model (B–MKFHE) that could resist more subfield attacks was presented. Secondly, based on the B–MKFHE model, the NTRU-type multi-key homomorphic evaluating structure was optimized by extending the dimension of ciphertext polynomial, so that the complicated and time-consuming key-switching operations were eliminated when running the homomorphic operations. Finally, combined the optimized multi-key homomorphic evaluating structure and modulus-switching technology, a leveled NTRU-type MKFHE scheme (M–MKFHE) without key-switching operations was constructed. The result showed that the proposed M–MKFHE scheme could resist the subfield attacks well and was proved to be IND–CPA security. Compared with the B–MKFHE, the memory (bit-size) and evaluating costs of the M–MKFHE are reduced, and the error magnitude is decreased in the homomorphic evaluating process. In all, the M–MKFHE scheme has higher evaluating efficiency and supports deeper homomorphic evaluations.关键词：NTRU-type MKFHE;prime cyclotomic rings;ciphertext extension;homomorphic evaluating structure;indistinguish-ability under chosen-plaintext attack (IND–CPA) secure
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发布时间：2024-01-08
CYBERSPACE SECURITY
- 摘要：In order to solve the deficiencies of existing image defogging algorithms, such as inaccurate estimation of the transmission in the sky or bright areas, image color distortion and serious loss of details, an adaptive transmission defogging algorithm based on linear transformation was proposed. Firstly, the input image was converted to the YCbCr space to extract the brightness component, and an anti-S type function was constructed to reduce the influence of highlighted pixels. Then a linear transformation model is used to enhance the compressed luminance component. In order to obtain an adaptive control parameter, a Gaussian function was adopted to convolve the luminance component. The minimum color channel of the fog-free image was approximated by combining linear transformation model and the adaptive control parameter , and further an accurate estimate of the transmission was obtained. Finally, the restored image was acquired by using the atmospheric scattering model and local atmospheric light in reverse. In the experimental verification part, visible edges, average gradients, saturated pixels, and structural similarity were used as objective evaluation indicators. The objective data illustrated that all indicators of the proposed method achieves better performance. In terms of subjective effects, the proposed algorithm is superior to several existing defogging algorithms. It can accurately estimate the transmission, effectively remove image fog interference and improve the color distortion of the sky or bright areas, improve image visibility, and restore more details such as image edges.关键词：image processing;anti-S type function;linear transformation;Gaussian function;adaptive parameter
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发布时间：2024-01-08 - 摘要：With the increase of online commodity transaction volume and the further development of social network, recommendation system has become one of important tools to solve information overload. However, when the data sparsity of the score matrix is relatively large, the recommendation accuracy will decrease significantly, especially when the user starts cold. A new social ranking recommendation algorithm based on implicit feedback information was proposed in this paper. The user preferences among different items using a matrix factorization method were first calculated by the proposed algorithm. Secondly, the user preference information was incorporated into the Bayesian Personalized Ranking (BPR) algorithm. Then, the similar relationships between users as well as direct and indirect relationships between trusting users were mined and quantified in order to study the differences of user preferences across projects. Finally, these trust relationships were fused with the BPR algorithm to build a social ranking recommendation model. To validate the proposed social ranking recommendation algorithm, the validity of the algorithm was verified on the DouBan dataset and FilmTrust dataset. The ranking evaluation metrics of Precision, MAP, and NGCD were used to verify the merits of ranking recommendation between the proposed algorithm and SBPR, TBPR, BPR, and MostPopular algorithms. The ranking recommendation tests were performed on these two specific social datasets for the full dataset and user cold start, respectively. The experimental results demonstrated that the proposed algorithm significantly outperforms other ranking recommendation algorithms and achieves better recommendation accuracy. It can be seen that the algorithm can improve the poor recommendation performance caused by data sparsity and user cold start.关键词：recommendation system;ranking recommendation algorithm;BPR algorithm;similar relationship;trust relationship
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发布时间：2024-01-08
INFORMATION ENGINEERING
- 摘要：High speed countercurrent chromatography has unique advantages in resolving the bottleneck of separation and purification of active ingredients in the field of biomedicine, such as no irreversible adsorption, high sample recovery and good tolerance.Therefore, it is necessary to improve the separation and purification efficiency of the existing small high speed countercurrent chromatograph and develop an industrial high speed countercurrent chromatograph with high efficiency, fast and large capacity.The structure of planet carrier of large-capacity high speed countercurrent chromatograph was taken as the research object. Firstly, the three-dimensional structure of the planet carrier was designed in the software. Secondly, the finite element model was established on the platform of hyperWorks. Static analysis and modal analysis were carried out by applying loads and constraint conditions on the planetary frame according to the characteristics of forces. It was found that the maximum deformation and maximum equivalent stress are both small, and the first order natural frequency is high.The structure can be further optimized. Based on the SIMP interpolation model of variable density method, a mathematical model of multi-objective function for improving stiffness and reducing flexibility was established by using compromise programming method. The structural topology optimization of the planet carrier was carried out, the material distribution was more reasonable, and the optimized structure was obtained. Based on the optimization results, the new planet carrier was redesigned, the dynamic and static simulation analysis was carried out again to ensure the rationality of the improved design of planet carrier structure. The research showsed that results of simulation analysis validate the safety and reliability of the structure.The optimized planet carrier can meet the requirements in various performances, and the quality was reduced by 13.1%.A new structure that is superior to the original structure was obtained.关键词：HSCCC;planet carrier;static analysis;topology optimization
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发布时间：2024-01-08 - 摘要：A large number of dynamic pressure sensors are used to evaluate and test in the development of equipment and engineering application. In order to improve measurement accuracy and data reliability and solve the problem of traceability of amplitude sensitivity of dynamic pressure sensor in high frequency sinusoidal pressure calibration, a method based on laser interferometry to measure the refractive index of liquid medium changing with pressure is applied to calibration the device of high frequency liquid sinusoidal pressure. Using piezoelectric stack effect and cavity resonance principle, the sinusoidal pressure signal with frequency up to 30 kHz can be driven by liquid medium. Based on Lorentz-Lorenz theory, a mathematical model of pressure and liquid optical path is established. Laser interferometer is used to measure the change of optical path in liquid, and the magnitude of sinusoidal pressure is obtained, so that the sinusoidal pressure amplitude can be traced back to basic quantity. Combining with the actual calibration process, the influence factors such as uneven pressure distribution, temperature change, structural deformation, vibration are analyzed theoretically and experimentally. Based on the high frequency liquid sinusoidal pressure calibration device of laser interferometry, the uncertainty of amplitude sensitivity calibration of dynamic pressure sensor is evaluated. The results show that the sinusoidal pressure range of calibration device of high frequency liquid sinusoidal pressure by laser interferometry is 0.01～1.00 MPa, the static pressure environment can achieve 0～10 MPa, and the expanded uncertainty of amplitude sensitivity calibration is within 7.6% in the frequency range of 1～30 kHz.关键词：sinusoidal pressure;laser interferometry;dynamic calibration;pressure transducer;refractive index
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发布时间：2024-01-08 - 摘要：The locally resonant phononic crystals have low frequency elastic bandgap characteristics and important application prospects in the field of vibration and noise control. The structure of three-dimensional locally resonant phononic crystals is mainly based on a multi-component material system, which limits its manufacturing and application for practical engineering. Therefore, a three-dimensional phononic crystal structure composed of single-phase material is proposed. The band structure, vibration mode and transmission spectrum of the phononic crystals are calculated by finite element method. The numerical results show that the structure can open a 20% complete bandgap within the range of normalized frequency below 0.1. The local resonance of the spherical mass element and the connectors is the main cause of the bandgap. The change of structural material properties affects the frequency of the bandgap, and the structural geometric parameters determine the relative position of the band gap in the whole band structure. The width and position of phononic band gaps can be manipulated via the materials and geometric parameters of the structure. In addition, the further widening of the band gap can be realized by constructing gradient structures with gradually changing geometric parameters. The three-dimensional structure composed of single-phase material can be used for the design and development of low-frequency vibration and noise reduction materials and devices.关键词：three-dimensional phononic crystals;single phase material;elastic wave band gap;vibration and noise reduction;modal analysis
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发布时间：2024-01-08 - 摘要：The direct-drive air bearing stage is a precise motion system integrating air bearing, servo drive and mechanical structure. There is more complex vibration characteristics in the stage. Generally, the vibration characteristics of the stage are analyzed by the vibration modes of the mechanical structure. But in engineering applications, the working modal of the stage under the driving force needed to be obtained. In this paper, to analyze the vibration characteristics of the working state of the stage simply, quickly and accurately, a new electric-mechanical coupling simulation method is presented. The servo characteristics of the drive system and the film characteristics of the air bearing were all equivalent to the spring damping units, and the electromechanical coupling simulation model of the direct-drive air bearing stage was established. Based on the model, the vibration modes under the working condition of the stage were obtained. To validate the analysis method, the LMS modal test instrument was used to test the modal of the real stage. The experimental results were consistent with the simulation results. The experimental results suggested that the maximum vibration deviation of the vibration modes calculated by the electromechanical coupling method was 8.16%. The experiments showed that the vibration characteristics of the working state of the stage could be accurately analyzed by the electromechanical coupled modal analysis method.关键词：air bearing stage;electric-mechanical coupling;operating modal;modal test
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发布时间：2024-01-08
MECHANICAL ENGINEERING
-
Numerical Simulation of the Temperature–electrical Field Characteristics in DC Arc Plasma Torches AI导读
摘要：Due to the high utilization rate, clean process and good effect of thermal plasma technology, it has become a hot development technology in solid waste incinerations. Among them, DC arc plasma is a key research technology in the field of radioactive solid waste treatment in recent years. The industrial plasma torch is the core device to realize this technology. But the internal temperature is extremely high, the temperature field and the electromagnetic field are coupled, and the experimental test is difficult. Therefore, the development and optimization of the device must rely on numerical simulation. Based on the secondary development functions of user-defined function and user-defined scalar and by analyzing the thermodynamic characteristics of the thermal plasma, the numerical simulation process was dynamically linked to the physical property parameters of the working gas, the source terms of the control equations and the electrode current distribution, thereby establishing two-dimensional axisymmetric Magnetohydrodynamics model. And using reasonable boundary conditions, the distribution law of characteristic physical parameters in the plasma torch was obtained by solving the hydromechanical control equations and Maxwell equations. The results showed that the potential drop was significant and the current density distribution was concentrated near the cathode; under laminar flow conditions, the temperature distribution in the arc column area was uniform, the center temperature was the highest in the entire basin, and the temperature gradient at the edge of the area was large; there was a dense current distribution area near the anode, which could be used as the basis for arc root position prediction. In view of the adhesion of the arc on the electrode surface, the electrode-plasma-coupling model can be calculated to obtain a more accurate temperature distribution on the inner wall surface of the device.关键词：plasma torch;DC non-transfer arc;solid waste treatment;numerical simulation;secondary development functions of Fluent- 2186
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发布时间：2024-01-08 - 摘要：Main purpose of this study was to prepare nicotine organic salt complex and provide a new nicotine addition form in smokeless tobacco products. Nicotine-mandelic acid complexes were synthesized by ultrasonic heating and stirring, and nicotine-mandelic acid crystals were obtained. Nicotine-mandelic acid crystal structure solved by SXRD belongs to orthonormal crystal system with space group P212121, the cell parameters are a=0.950 74 nm, b=1.272 46 nm, c=2.04101 nm, α=90°, β=90°, γ=90°, Z=4.In the crystal structure of nicotine-mandelic acid, nicotine ion and mandelic acid ion bind tightly and form a diamond grid structure, a neutral mandelic acid molecule is inserted into each diamond lattice. According to Hirshfeld surface analysis, the hydrogen bonds of N2−H2···O5, O6−H6A···O5, O8−H8···N1 make the electron density of molecules at that point is more intensive, which leads bright red areas on Hirshfeld surfaces mapped with dnorm. 2-D fingerprints show that H plays an important role in the intermolecular interaction of nicotine-mandelic acid crystals. The result of interaction energy analysis is that 21 kinds of intermolecular interaction energies exist in nicotine-mandelic acid crystal structure. Because of the existence of N2−H2···O5, O6−H6A···O5, O8−H8···N1 hydrogen bonds, the interaction between nicotine ions and neighbouring mandelic acid ions or mandelic acid molecules can be significantly greater than others. Energyframe model was used for visualizing the interaction energy in the nicotine-mandelic acid crystal structure which can be applied to understand the interaction energy more conveniently and clearly. this results have important theoretical guidance and application value for exploring the chemical binding form of nicotine and formulation design of smokeless tobacco products.关键词：nicotine;mandelic acid;crystal structure;hirshfeld surface;intermolecular interaction energy
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发布时间：2024-01-08 -
Study on Flue Gas Desulfurization with Oxide Manganese Slurry for Electrolytic Manganese Calcining AI导读
摘要：For traditional wet limestone wet flue gas desulfurization process, excepting for high cost, a large amount of gypsum byproduct was formed, which was difficult to be reused, and resulted in many new environmental problems. However, flue gas desulfurization with oxide manganese slurry could remove SO2 and produce MnSO4 simultaneously. Based on the characteristics of electrolytic manganese industry, a new technology for sulfur dioxide recycling and removal from flue gas of electrolytic manganese residue calcination process was presented using the manganese oxide ore (raw material from electrolytic manganese industry) with anode solution of electrolytic manganese slurry, and the influences of processing parameters were investigated in the present work. The process experimental investigations on flue gas desulfurization and manganese leaching with electrolysis anode solution and manganese dioxide ore slurry indicated that as desulphurizing time increased, the higher SO2 concentration of flue gas, the lower the desulfurization efficiency was obtained, and the manganese leaching rate increased, thus multistage countercurrent mode should be adopted to realize efficient desulphurization and manganese leaching. The desulfurization rate increased with the decrease of the granule size of manganese oxide and the size of the manganese ore used for desulphurization should be less than 120 mesh. The operating temperature of flue gas desulfurization should be controlled in the range of 50～80 ℃, while the liquid-solid ratio should be in the range of 9∶1～6∶1. For different processing installations, the relative optimum inlet flow was different and for the applied experimental installation, i. e. 2.0 m3/ min. The simulation of anode solution was used to conduct 5 grade manganese oxide slurry desulfurization of the simulated 7% flue gas calcination, and the results showed that with the liquid-solid ratio at 9∶1, ore particle size at 200 mesh, the temperature at 50 ℃, the time of 4 grade desulfurization at 20 min, the outlet SO2 concentration was 111.4 mg/m3, leaching rate was 93.12%, concentration of Mn2+ was 46.26 mg/L in slurry, and concentration of MnS2O6 was 4 g/L (for fifth grade (100 min). The present work provided a new technology for sulfur dioxide recycling and removal from flue gas using the manganese oxide ore with anode solution of electrolytic manganese slurry. Compared with the traditional method of sulfur resources utilization, the cost of the present method was significantly reduced.关键词：manganese oxides ore;desulfurization;anode solution of electrolytic manganese;Mn leaching- 2022
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发布时间：2024-01-08 - 摘要：With the application of more and more complex oil and gas production technologies, the field service environment in oil and gas fields has become harsher. Furthermore, some field operations (water injection, agent injection, annular nitrogen injection, reinjection of CO2, pressure testing, etc.) will lead O2 into the downhole environment. O2 is highly corrosive and it may cause some unexpected and severe corrosion risks of the downhole tubing, particularly for 13Cr and some other stainless steels, O2 interfusing can significantly increase the localized corrosion risk and brings a lot of corrosion problems during oil and gas exploitation. In this study, the corrosion behaviors and localized corrosion mechanisms of plain and super 13Cr stainless steels under high temperature and high pressure in O2-contained bromine completion fluids was investigated by corrosion simulation tests and surface characterizations. The corrosion simulation test was performed by high temperature and high pressure autoclave. The corrosion product film that formed on the steel substrate was analyzed by scanning electron microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) techniques. The results showed that both plain and super 13Cr steels exhibit bad corrosion resistance in O2-contained bromine completion fluids with various KBr concentrations. Particularly for localized corrosion rate, the corrosion grades of both plain and super 13Cr steels reach to extremely serious. According to NACE PR—0775 standard, the plain 13Cr steel in the solution of 1.01 g/cm3 reaches the severe corrosion degree, and with the increase of bromine concentration, the degree of corrosion increases, reaching extremely severe corrosion at 1.10 g/cm3. With the increase of bromide concentration, the corrosion rate increases evidently. Even if the super 13Cr stainless steel is subjected to a high bromide concentration, it can still experience severe localized corrosion (> 5 mm/a). The microscopic morphology analysis showed that the pitting initiates at the damaged area of the Cr-rich passive layer on substrate surface. The corrosion products accumulate around the pitting. As a result, a local galvanic effect forms between the pitting and the surrounding area, which further accelerates the propagation of the pitting.关键词：bromine completion fluid;oxygen corrosion;plain 13Cr;super 13Cr;high temperature and high pressure;pitting corrosion
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发布时间：2024-01-08
CHEMICAL ENGINEERING & MATERIAL ENGINEERING
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