最新刊期
卷 48 ， 期 3 ， 2016
- 摘要：Abstract:Debris-flow is a kind of two-phase fluid, which contains liquid-phase with slurry and solid-phase with coarse grains. The resistance characteristics, which can be divided into internal resistance and external resistance, is a critical factor for the study of kinematic and dynamic of debris-flow.The external resistance caused by interaction between debris-flow and gully-bed and gully-wall depends on the roughness and geometric shape of gully and properties of debris-flow.The debris-flow can be classified into viscosity debris-flow and two-phase debris-flow for understanding their internal resistance characteristics. For the former, the solid-phase and liquid-phase during the motion have no obvious slip velocity, therefore viscosity debris-flow could be identified as a kind of homogeneous mixing fluid and modeled by pseudo-homogenous fluid. However, for the two-phases debris-flow, the solid-phase and liquid-phase have obvious slipvelocity;the stress forces due to solid-liquid interaction, such as viscosity drag force and virtual mass force etc., plays critical role, and thus the stress due to interactions of solid grains, which comes from granular flow, is a key factor. The Fine contents in liquid-phase slurry has a huge effect on the resistance character of a debris flow and can change the resistance character of liquid-phase slurry, including yield stress and viscosity coefficient. Furthermore, the viscosity coefficient of slurry can have effects on stress due to interaction of solid grains. In this study, a comprehensive resistance model of debris-flow, including internal resistance and external resistance, has been proposed.关键词：Debris-flow;Internal resistance;External resistance;Energy dissipation;Fine contents
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发布时间：2023-11-14 - 摘要：Abstract:In the past two decades, a series of exact analytical solutions to the two kinds of depth-averaged equations in water waves, i.e., the linear long-wave equation and the mild-slope type equations, have been constructed. For the linear long-wave equation, if the bottom topography is idealized with the water depth being a power function, then the related analytical solution can be written in a closed form. If the bottom topography is quasi-idealized with the water depth being a power function plus a constant, then the related analytical solution can be expanded into a Taylor series or a Frobenius series. For the mild-slope type equations, a number of exact analytical solutions in the form of Taylor series are constructed recently, where the implicit modified mild-slope equation is successfully transformed into an explicit equation for both two-dimensional bathymetries and three-dimensional axisymmetric bathymetries with piecewise monotonicity and piecewise second-order smoothness. In this paper, these advances are summarized and reviewed. And some prospects of the research in the future are made关键词：the long-wave equation;the mild-slope equation;linear wave dispersion relation;implicit function;explicit form;analytical solution
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发布时间：2023-11-14 - 摘要：Abstract:Abstract:【Objective】In order to optimize the size and layout of discharge structure, explore the relevance between flow field distribution and local scour of the river bed.【method】Physical experiments in a large-scale hydropower station surface and bottom joint flood discharge facilities based, used standard turbulence model and VOF free surface capture technology, three dimensional flow field of the combined flood was numerical simulated , obtained the flow velocity ,water line and pressure hydraulic characteristics of the surface orifice spillway, bottom outlet and the pond. By comparing with the experimental results of hydraulic model, the correlation mechanism between the flow field structure and the downstream channel scour pattern was analyzed.【Result】Results show that: the original design of the stilling pool water fluctuation, flow disorder, pool water secondary sag and mainstream dive riverbed, lateral diffusion is not sufficient. The corresponding physical model, which occurs serious erosion in the downstream. Erosion is the most serious on the right bank and behind the left guide wall of surface hole, is just on the right bank of the mainstream posted shore and left back pressure area. Through improved the shape of the plunge pool with the methods of retaining the construction diversion wall between low porosity and surface hole stilling pools and so on, significantly improved the flow regime of stilling basin, the pool water secondary drop decreases, dive is weakened, a pool level of the mainstream diffusion more fully, lateral extrusion can be suppressed sufficiently. Accordingly, the scope and depth of the riverbed erosion are greatly reduced, especially on the right bank side corresponds to the original proposal prepared hole area almost no erosion occurs.【Conclusion】Obviously, in the simulation of local scour is still not mature , based on flow field analysis method for trend analysis of riverbed scouring, layout and shape optimization and direct discharge structure is feasible.关键词：numerical simulation;energy dissipation by hydraulic jump;optimal design;second drop of water;scour trend
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发布时间：2023-11-14 - 摘要：Abstract:For movable bed model, sand wave movement similarity is the basis of the similarity of flow, sediment transportation and river bed evolution. Based on flume experiment, which meets the similarity of geometric, flow and incipient motion, similarities of sand wave height and its composition were analyzed. The results show that: firstly, for the normal model with the same weight ration of prototype sand and model sand, sand wave height is largely in line with geometric similarity and the average deviation is only about 9.2%. Furthermore, sand wave height varies with flow intensity. Sand wave emerges when u/uc is 2.0 and extends with increasing flow intensity. Sand waves reach their maximum height when u/uc is 2.6. Finally, particle composition in the same part of different sand waves is similar. In conclusion, with the same density and shape, natural sand wave and model sand wave correspond to the similarity law in a normal mold when incipient motion is taken into consideration.关键词：sand wave similarity;sand wave height;flow intensity;particle composition
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发布时间：2023-11-14 - 摘要：Abstract:The impact test of self-excited inspiration pulse jet device was conducted by using homemade jet experiment platform. The time-varying process of typical measuring points pressure and target center impact were measured. The water-gas flow process inside the device has been recorded with a high-speed digital camera. The pulse effect of typical measuring point pressure and impact was analyzed under different structural parameters and operation parameters. The relationship among typical measuring points pressure, impact pulse effect and water-gas flow process was studied. The result shows that cavity length, nozzle diameter, working pressure and confining pressure had obvious influence on inspiration capacity. Cavity length and under nozzle diameter had significant influence on collision body measuring point pressure pulse effect, impact time-averaged value and pulse effect, and there were optimal structure parameters that make inspiration capacity, impact time-averaged value maximize and pressure pulse effect best. Work pressure and confining pressure had greater influence on the impact time-averaged value and pulse effect. The gas-water rotating vortex inside the cavity was formed after inspiration. There existed obvious corresponding relation between the gas-water rotating vortex and pulse effect of the collision body measuring point pressure and impact, so the reason of pulse jet was explained.关键词：self-excited inspiration;pulse jet;pressure;flow characteristics
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发布时间：2023-11-14 - 摘要：Abstract:In order to study the dynamic response of homogeneous soil slope supported by anchors and lattices under seismiv loading, based on the shaking table test , the mechanism behavior of anchor bars under earthquake, and the difference of dynamic response of anchor bars at different heights were analyzed, and the deformation and failure machanisms of homogeneous soil slope and its supporting structures under seismic load were discussed. Experimental results showed, under dynamic loading, the dynamic strain of anchor was hypersensitive to low-frequency and high magnitude of acceleration of earthquake wave; acceleration magnitude changed from low to medium to high, the position of the bolt to bear larger load also changed in anchored slope, the corresponding order was from middle to top to middle; if the earthquake intensity was large enough, the middle anchor would be damaged firstly, followed by the bottom bolt. The traditional design idea “strenthening slope waist and fixing slope toe” should be used when an anti-seismic anchorage system is designed to make a slope stable. In addition, strengthening the anchor heads of top-row anchors and the upper slope face is a good method to protect the slope from being influenced by the seismic superficial effect. The difference of slope dynamic response should been fully considered under small or big earthquake. The results provided a reasonable foundation for the design of the anchor bars supporting under earthquake．关键词：homogeneous soil slope;earthquake;dynamic response;shaking table test;ancho
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发布时间：2023-11-14 - 摘要：Abstract:For research the relationship between pressure and displacement of retaining structure, a method for calculating the non-limited active earth pressure of retaining structures under the influence of the external wall of basement was proposed. Based on the unloading path, the mechanical parameters of soil and the displacement relationship and the non-limited active earth pressure coefficient were deduced. Then, the stress state method and the forces equilibrium method were used to solve the non- limited active earth pressure, and by comparing indoor physics experiments, the results of the stress state law were relatively closer to reality than forces equilibrium method. Based on the variation of active earth pressure of retaining structure, the influence of displacement ratio, two walls pacing, wall friction angle and cohesive force on earth pressure distribution, resultant force and overturning moment were discussed. The comparison between the results of the physical experiments and numerical examples and theoretical calculation method of the soil pressure and torque showed that the calculation method is reasonable and feasible, which provides a basis for further study of the non-limited active earth pressure theory.关键词：existing basement;active earth pressure;non-limited state;arching effects
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发布时间：2023-11-14 - 摘要：Abstract:Abstract: In order to study the relationship between landslides and rainfall, the antecedent effective precipitations of different return period were used to analyze the influence of soil moisture on the shear strength parameters of soil body and matrix suction. Then a new method was presented to quantitatively evaluate landslide failure probability under different rainfall return periods based on response surface and simplified Bishop integral method. In additional, the method was applied to in an example and the result showed that a higher failure probability of landslide was calculated with the increase of rainfall return period and rainy days. But considering the probability of rainfall itself, a growing rainfall return period did not mean increase in failure probability of landslide. A slightly stability factor and a lower failure probability of landslide can be calculated based on matrix suction.关键词：rainfall-induced landslide;antecedent precipitation;Bishop integral method;response surface;probability analysis
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发布时间：2023-11-14 - 摘要：Abstract:In order to study the stress-strain relationship of concrete under sulfate attack and freeze-thaw cycles, the uniaxial compression experiments of concrete subjected to freeze-thaw cycles in water, and mass fraction of 5% sodium sulfate, 5% magnesium sulfate solution were carried out. The effects of sulfate solution and freeze-thaw cycles on the peak stress, peak strain, elastic modulus and stress-strain curve of concrete were investigated．Furthermore, the mechanical property of the damage layer of concrete was analyzed. The results show that the stress-strain curve is flat and moves to the right with freeze-thaw time increases. The rising step of stress-strain curve rises slightly, and the curve is concave when concrete subjected to 300 freeze-thaw cycles in the sulfate solution. Along with the freeze-thaw cycle increases, the peak stress and elastic modulus of concrete decrease, and the peak strain increases gradually. This phenomenon is more obvious when concrete exposed to magnesium sulfate solution, and the frost resistance of concrete is the worst. Through regression analysis, the uniaxial compressive stress-strain curve equation under sulfate solution and freeze-thaw cycles is proposed to fit the test results. Moreover, the peak stress of the damage layer of concrete is obtained when exposed to different freeze-thaw cycles.关键词：concrete;sulfate attack;freeze-thaw cycles;uniaxial compression;stress-strain curve
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发布时间：2023-11-14 - 摘要：Abstract:In order to solve the inadequacies of existing calculation and allocation methods of the power generation compensation benefits (PGCB) which come from united operation of cascade reservoirs, a new concept, electric energy benchmark of hydro plant, was proposed and used to calculate PGCB, and also a new model for allocating PGCB among cascade hydro plants was developed, which can balance the subjective preference of each plant and the group consistency of all plants. The proposed computing method takes into account TOU power price differences among different plants and load rate constraint from power grid for the electric energy output increasing of every plant, which makes the method get closer to the real value of PGCB. According to the benefits-sharing principles selected by involved parties, the proposed model firstly gets the individual preference weight vector of every plant for the principles by solving an optimal model whose goal is maximum single plant apportionment ratio; secondly, reach a consensus on the weight vector through maximizing group consistency; finally, the actual benefits –sharing proportion of every plant is fixed by solving another optimal model whose goal is minimizing the distance between the final values and the results from all the different principles. Moreover, an improved partheno genetic algorithm, whose genetic operation is simple and more efficient, was presented and adopted to solve all the relevant optimal models. A case study shows that the proposed computing method and benefits-sharing model work well, and the results are reasonable and can be accepted more easily.关键词：united operation;electric energy benchmark;compensation benefits allocation;improved partheno genetic;cascade hydropower stations
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发布时间：2023-11-14 - 摘要：Abstract:In order to fulfil the contour extraction of left atrial appendage (LAA) from the low resolution, low contrast and noisy transesophageal ultrasound images automatically, a new method was proposed, which combines the anatomical knowledge of LAA and the information of intensity and phase in ultrasound images. Firstly, to locate the effective initial contour with the characteristic of intensity and geometry from LAA ultrasound images, the anatomy location of LAA in the standard section is taken as the priori-knowledge based on the physicians’ collecting habit. Then, to improve the convergence performance of classical Vector Filed Convolution (VFC) model, a new external force term was proposed by combing phase and gradient information in the linear weighting method. According to the test results conducted from 300 frames, it shows that, this method can reach the accuracy of 0.8969 0.0494, sensitivity of 0.9058 0.0762 and specificity of 0.9645 0.1687 by regarding the contours outlined by physicians as “golden standard”. Comparing with traditional VFC model, this method owns better segmentation performance by determining a more suitable initial contour and is more robust to weak edge.
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发布时间：2023-11-14 - 摘要：Abstract:In order to solve the existing problem of the sketch recognition heavily relying on the manual feature extraction which was very time-consuming, this paper proposed a method of sketch recognition based on deep learning, called Deep-Sketch. The classical deep learning models were mainly designed for natural color image recognition which failed on the sketch recognition. Deep-Sketch aimed to obtain more spatial structure information by using the large-size convolution kernel instead of the small-size convolution kernel in the first convolution layer. In addition, a shallow model was trained to obtain parameters which were used to initialize the corresponding layer parameters of the Deep-Sketch to reduce the model training time. Deep-Sketch was deepened with the convolution layers which kept the feature size to reduce the error rate. The results showed that the Deep-Sketch was superior to other state-of-the-art sketch recognition methods and achieved 69.2% accuracy on the sketch dataset including 250 classes关键词：sketch recognition;deep learning;convolution neural network
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发布时间：2023-11-14 - 摘要：Abstract:Assigning an eye task with visual stimulation and tracking the eye movement is a channel to acquire the examinees’ psychological behaviors, which plays a critical part in the fields of psychological research. In this study, an eye-tracking system based on FPGA hardware and projection algorithm is proposed. It captures video via LUPA300 high-speed CMOS and obtains the motion of eye pupil and bright spot through the continuous video frames by using a FPGA implemented a projection algorithm. To obtain a reliable tracking accuracy, a binarization and mathematical morphology operation (corrosion and expansion) are adopted as a pre-procession step. The results show that FPGA can implement projection algorithm to track eye motion at high speed, the binarization and corrosion expansion pretreatment can improve the tracking accuracy effectively. The system is easy to achieve the real time tracking, and provides an new method for eye movement tracking at high speed.关键词：Eye movement;FPGA;Motion tracking;Projection algorithm;corrosion;Expansion
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发布时间：2023-11-14 - 摘要：Abstract:In order to discover MPSoC's design defect earlier, a formal method for depicting core coordination was proposed, including structural model and logical characterization. The main idea was to adopt polynomial functions to replace actions on labelled transition system to describe data changes among different states. Combining with the malfunctioning probability of physical components, a hybrid Markov decision process model was formulated to describe the reliability and performance of the core coordination. Then system properties was depicted by the probabilistic computation tree logic and verified by model checker. Finally, an experiment using data desensitization MPSoC in banks was carried out and a result including the system reliability and time latency as well as power consumption was analyzed. The study is valuable for early MPSoC designers.关键词：multiprocessor system-on-chip;core coordination;hybrid labelled transition system;hybrid markov decision process;probabilistic computation tree logic;PRISM;data desensitization
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发布时间：2023-11-14 - 摘要：Abstract:In order to solve airport traffic congestion, reduce flights delay, improve the profits of airlines and reduce fuel burn and emissions，the method of flights waiting in stands in steading of taxiing queue waiting before the end of takeoff runway was presented. Based on Collaborative Decision Making, the construction of Virtual Queue was designed and three kinds of pushback strategies for delayed flights were proposed, which were Minimis Unfairness, Minimis Passengers Waiting Time, and Minimis Pushback Waiting Cost. Several metrics were presented for the strategy. Various scales of numbers of flights experiments were executed and each metric was carefully compared following the growing of length of virtual queue. The trade-off passengers’ benefit, flights postponed waiting time, and pushback delay cost were analyzed. As for as the result of example show that sorting flights in the virtual queue had reduced passengers waiting time and saved airlines cost effectively.关键词：Air Transportation;Airport Collaborative decision making;departure queue management;Collaborative virtual queuing;sorting
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发布时间：2023-11-14 - 摘要：Abstract:Abstract: In order to solve the mutual interference problem in heterogeneous networks, coordinated multi-point (CoMP) transmission technology was proposed to interference elimination for heterogeneous networks. When the end users configure multiple antennas, the coordinated transmission delay and channel quantization errors were considered jointly how to affect the interference elimination. By mathematical theory, the system throughput loss caused by the negative factors was analyzed, and the theoretical throughput loss upper bound was obtained. The simulation results showed that the throughput loss can be decrease by CoMP technology, which was meaningful for the actual system.关键词：heterogeneous networks;CoMP;transmission delay;quantization errors
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发布时间：2023-11-14 - 摘要：Abstract:In order to jam overall radar net best, to address problem that the radar jammer power is allocated optimally to all radars in radar net, the two-person zero-sum game theory (TPZS) is proposed to distribute jamming power to radars. By expansion of jamming vector, emission vector and other vectors, the vectors are transformed to matrixes. Jammer jams each radar in network by certain powers by calculations with TPZS theory based on mutual information, the power distribution can be calculated in the case of different distances, different suppression coefficient of the radars. Under the condition that the total power of jammer is limited, the jamming power can distributed to the radars in network reasonably. Simulation shows in most cases that the needful jamming power of TPZS is more less than regular proportion method in condition that the radar net can be jammed effectively. For the jammer, radars in network are different more big, the TPZS method can embodies its superiority more. Since the mutual information theory of TPZS can be used to characterize detecting overall effect of radar net comprehensively and systematically, the jamming want to reduce the amount of the mutual information by jamming with TPZS for power allocation. Based on the guideline, the allocation of jamming resource is targeted and the overall jamming effect is good.关键词：radar net;active jamming;power distribution;mutual information;two-person zero-sum game;vector expand
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发布时间：2023-11-14 - 摘要：Abstract:Performance of adaptive active vibration control algorithm may degrade if there exists frequency error between the reference signal and primary vibration with multi-line spectra due to the limited situation in the application of active vibration control of water pump. To tackle this problem, an active vibration control algorithm is proposed based on the adaptive feedback FXLMS (filtered-X least mean square) algorithm with adaptive self-generating reference signal. The phase of the reference signal was updated based on geometry relation, besides the frequency of reference signal was estimated by related coefficient based on least mean square method. Simulation and experiment was conducted to validate the effectiveness of the proposed method. Simulation results validates that the algorithm could achieve effective performance by adaptively regulating the frequency of reference signal with the existence of frequency error between the reference signal and primary signal. Experiment of active vibration control of water pump confirms the effective performance of the proposed algorithm.关键词：线谱振动;振动控制;自适应控制
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发布时间：2023-11-14 - 摘要：Abstract:According the problem raised in compressive sensing theory that the classical measurement matrices (random Gaussian, random Bernoulli, etc.) does not achieve the optimal performance, the singular value decomposition is introduced in this paper, thus a novel method is proposed for the measurement matrix optimization based on singular value decomposition, to optimize the general linear measurement model in compressive sensing, i.e. measurement matrix and corresponded measurement vector, and then the original signal sparse signal is reconstructed by the optimized linear measurement model. Numerical results for the classical random Gaussian measurement matrix and random Bernoulli measurement matrix demonstrate that our proposed method can significantly increase the reconstruction probability of successful recovery and are more robust to Gaussian noise. Our proposed method is applicable to the general linear measurement system, which can successfully achieve the separation of the measurement matrix and the reconstruction matrix, and make the reconstruction matrix close to the most excellent configuration without the any model change at the front end of the measurement system.
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发布时间：2023-11-14 - 摘要：Abstract:In order to guarantee the physical layer security of the transform domain communication system (TDCS)， a security-enhanced scheme based on 4-Weighted-type Fractional Fourier Transform (4-WFRFT) and artificial noise insertion was proposed. Firstly, the 4-WFRFT was applied to TDCS instead of the Discrete Fourier Transform (DFT) and Inverse Discrete Fourier Transform (IDFT), which maintained the system complexity while made the distribution of TDCS signals change in the complex plane. And then the artificial noise is inserted to further enhance the security. The expression of the Bit Error Rate(BER) and the security capacity for eavesdroppper were obtained. Simulation results show that whether with or without spectrum mismatch, the BER for eavesdropper kept 0.5 and the security capacity is positive when in the range of [0, 0.8) or (1.7, 4] in the security-enhanced TDCS. It provides a promising solution to extend the application of TDCS scheme where secure communication is required.关键词：TDCS;4-Weighted-type Fractional Fourier Transform;artificial noise;physical layer security
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发布时间：2023-11-14 - 摘要：Abstract:Abstract: In order to hold the output voltage constant, stabilize system frequency when the load varies dynamically in inductive coupled power transfer(ICPT) system, this paper presents a double LCL resonant ICPT system (LCL resonant tank in both and pickup side). Firstly, this paper describes the stable voltage characteristics of ICPT system based on LCL resonant circuit in pickup side., presented the two design methods of the primary coin considered the reflected impedance in ICPT system based on LCL resonant circuit is capacitance-resistance, and the capacitive portion is unrelated to load dynamic variation. At the same time, describes the constant current characteristics of ICPT system based on LCL resonant circuit in primary side. Then, a general conditions is given under the conditions of load dynamic variation, which is effective to realize constant frequency (operating frequency is constant), constant current and stable voltage output. Besides, the influence of major performance parameters on the output characteristic is analyzed. Finally, the viability of the proposed system is verified by simulation and experiments, and the results suggest that the double LCL resonant ICPT system based on optimal parameters realizes the characteristics of constant frequency, constant current and stable voltage.
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发布时间：2023-11-14 - 摘要：Abstract: The tooth profile has an evidently influence on the transmission performance of harmonic drive (HD). For the purpose of improving the transmission performance of HD, double-circular-arc common tangent tooth profile (DCTP) as the tooth profile of flexspline (FS) was been used. The parametric equations of DCTP were established by using the arc length, and the conjugate existent domain (CED) and the conjugate tooth profile (CTP) were deduced based on Modified Kinematic Method, moreover, the CED and CTP variable law of HD that utilized the DCTP were studied. The results demonstrated that two CEDs are founded in the mesh process, what’s more, the two conjugate phenomenon and the twice conjugate phenomenon were deduced. The arc radius of the convex tooth profile, the arc radius of the concave tooth profile, the conjugate angle, conjugate domain, conjugate position, conjugate arc length and radius were obviously influenced by the common tangent tooth profile length, the obliquity angle between the common tangent and the symmetric line of the teeth, the coefficient of the radial displacement, and the wall thickness of FS. The transmission quality of HD device, in the research example, was improved by appropriately decreasing the abovementioned structure parameters and meshing parameters.关键词：harmonic drive;double circular arc tooth profile;parameters influence;conjugate analysis
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发布时间：2023-11-14 - 摘要：Abstract:As a new worm drive, planar tooth internal gear enveloping crown worm drive is composed of a planar tooth internal gear and a crown worm generated by the planar tooth internal gear surface. It is characterized with small size, light weight and high power density, and has wide application prospects on the special service overloaded transmission areas with the size and weight restrictions. In order to grasp the accuracy theory of planar tooth internal gear enveloping crown tooth surface, the mathematical model with process errors is established based on the differential geometry and meshing theory, and the data collection methods are analyzed based on the gear measuring center. The probe radius compensation principle and tooth match method are studied, as well as the optimization of tooth surface errors tracing is proposed. The experiments of tooth surface errors measuring and errors tracing are carried out, and the feasibility is verified. This study is expected to give theoretical guidance to the accuracy assessment and high-precision amend manufacturing of planar tooth internal gear enveloping crown tooth surface, and it is propitious to the promotion and application of internal gear enveloping crown worm drive.关键词：crown worm drive;tooth surface errors;measuring;tracing
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发布时间：2023-11-14 - 摘要：Abstract: In order to study the influence of the torch constriction on the thermal efficiency, and then to guide the design of laminar plasma torch, the arc voltage and thermal efficiency of two laminar plasma torches with different constriction, working with the same working parameters, were obtained by experiments. Based on the experimental results, the arc voltage and thermal efficiency of the two plasma torch were compared and analyzed. The results show that: working with pure Nitrogen, although the arc voltage of the segmented anode laminar plasma torch (MEPT) is much higher than that of the conventional laminar plasma torch (TEPT), the thermal efficiency of MEPT is much lower than that of TEPT.关键词：Laminar plasma;Torch structure;V-A characteristic;Thermal efficiency
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发布时间：2023-11-14 - 摘要：Abstract:The cable harness branches assembled in aircrafts can be separated by fix points into a number of cable harnesses between the adjacent fix points. One kind of these cable harnesses between the adjacent fix points, which has the assembly feature: one fix point being a mechanical protection and the other fix point being electrical connector, is defined as the end cable harness between the adjacent fix points(''the end cable harness'' for short) in this paper. The principle of determining the lengths of cable harness branches in prototype was revealed, it is proposed that the unit lengths of determining cable harness branches in prototype are lengths of cable harnesses between the adjacent fix points. And the process for assembly workers to determine the length of one cable harness between the adjacent fix points was abstracted as a kind of iterative approach in which its length was determined by justifying whether the process geometrical requirement and the process clearance requirement could be met or not under a given possible lengths. On the basis of that, the length model of the end cable harness was developed to calculate its maximum and minimum length values in the computer platform. To solve the model, the preliminary geometry model for this kind of cable harness was proposed by 6R robot arms, in which the end cable harness’s stiffness could be simulated by adjusting the ratio of lengths of the six rods. Then based on the minimum curve energy method, the refined geometric model was proposed where the center line of the main body of the preliminary geometry was refined to an arc with common end points and same length, the gap detecting precision was improved. Finally, the length model of the end cable harness was programmed in VR environment and the calculating result of an entire example was verified by experiments.关键词：Aircraft cable harness;Branch length of cable harness;Prototype installing;Process requirements;End cable harness between the mechanical fixed point and the electrical fixed point;Process length modeling
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发布时间：2023-11-14 - 摘要：Abstract:UV-visible-shortwave near infrared diffuse reflectance spectroscopy (UV-vis-SWNIR DRS) combined with chemometrics was firstly used as a new method to analyze enantiomer and its racemic compound, using D-, L- and DL-alanine as model compounds. Under the optimal measuring conditions(powder particle sizes of 100-mesh and distance between fiber probe and sample of 5.6mm), after spectral pretreatment and/or wavelength selection, principal component analysis (PCA) and discriminant partial least squares (PLS-DA) resulted in a correct discrimination of chirality with 100 percent accuracy; partial least squares regression (PLR) and support vector regression (SVR) models allowed a satisfied quantitation of D/L binary mixture with determination coefficients (R2) above 0.99 and 0.98 for calibration set and prediction set respectively by both PLR and SVR, and ratios of performance deviation (RPD) far above 2. The results show that it is feasible to apply UV-vis-SWNIR DRS on chiral analysis of compounds.
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发布时间：2023-11-14 - 摘要：Abstract:The leakage calculation method and leakage mechanism of micro-pores mechanical seal are not clear. Based on the mass-conservative JFO cavitation boundary condition, a numerical calculation model was developed for the mechanical seal with micro-pores. The numerical calculation results showed that the flow rate was not equal at different cross sections along the leakage direction. Therefore, it is necessary to select a reasonable integral cross section to make the leakage calculation correct. Furthermore, the reason why the flow rate along the leakage direction is not equal was discussed through the analysis of the radial flow field, the circumferential flow field and the pressure field. It was also proposed that the leakage was reduced because the high pressure region, which was induced by the dynamic pressure and cavitation, changed the flow from leakage direction to circumferential direction. Finally, the formula and method for the leakage calculation of mechanical seal with micro-pores were presented.关键词：mechanical seal;micro-pores face;leakage;dynamic lubrication;cavitation
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发布时间：2023-11-14 - 摘要：Abstract:The aim of the present study was designing a novel drug carrier system composed of the block copolymer PBLA-POLO-PBLA via ring-opening polymerization of the β-benzyl-Lasparate N-carboxyanhydride (BLA-NCA) monomer which was initiated by poloxamer 188. The polymers were characterized and confirmed by 1H-NMR, Fourier transform infrared assay (FTIR) and gel permeation chromatography (GPC). Then, studying with A549 cells to evaluate the material`s cytotoxicity showed that the copolymer was nontoxic. PBLA-POLO-PBLA nanoparticles loaded with Valaciclovir (VACV) were prepared by the emulsion-solvent evaporation method, and the physicochemical properties were also investigated afterwards. The transmission electron microscope (TEM) showed that the VACV-loaded nanoparticles had a sub-micron size with a spherical shape. The VACV-loaded nanoparticles (with a loading efficiency of 4.36%) showed a sustained release of VACV molecules (with 70.22% release in 96 h) which was determined by HPLC at 251 nm. These results suggested that PBLA-POLO-PBLA block copolymer was a promising nano-carrier in nanoparticle drug delivery systems.关键词：Poloxamer;PBLA;Block copolymers;Nanoparticles;Carrier
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发布时间：2023-11-14 - 摘要：Abstract: This research adopts the diethyl hydroxylamine (DEHA) promote ozone (O3) degradation of dimethyl phthalate (DMP), and established the O3 / DEHA system that can enhanced O3 oxidation ability. It mainly explored the effect of pH, DEHA dosages, ozone flux and DMP dosages in O3 / DEHA system and the oxidation mechanism in the system. And the degradation products were analyzed through gas chromatography /mass spectrometry (GC/MS). Experimental results showed that the DEHA can effectively promote the decomposition of ozone and obviously improved DMP degradation rate under acid condition (pH = 3), the promoting effect was best when DEHA dosage was 25 μΜ. DMP degradation rate increased with the increase of ozone flux, and increased with the decreases of DMP concentration, the reaction conformed to the first order kinetics reaction by dynamics calculation. Adding tert-butyl alcohol (TBA) significantly inhibited the degradation of the DMP, confirmed the ·OH plays an important role in the degradation of DMP under acid condition. Through the analysis of the product, it can be deduced that DMP degradation pathway in O3 / DEHA system mainly started from the chain scission of benzene ring, and then the intermediates transformed to esters molecules and acids which were finally mineralized to water and carbon dioxide.
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发布时间：2023-11-14
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