Abstract:In the no nlinear numerical simulation of finite element for materials，components and structures，the load increment control method is usually powerless when it is necessary to reach or pass through the peak point and the softening decent segment of special equilibrium path for load-displacement relation. In this paper，a new theory of displacement control proposed by Du Xiuli et al. is used to overcome this problem. To make a new stiffness matrix symmetric and banded，the main diagonal elements of stiffness matrix in the conventional finite element incremental equation were multiplied by a huge number，and the boundary conditions were also introduced to the finite element equation. Therefore，only a little modification was needed for the program of traditional load control method which can simplify the iterative process of calculation. Finally，the complied program MATLAB was used to analyze some practical examples. It is shown by the analysis that the method presented in the paper is not only effective，feasible，but also simple.

Abstract:The two-dimensional metal organic framework(2D MOF) with the ultra-thin thickness and the large transverse size and the surface area presents the low resistance and high throughput in the process of material transport in comparison with 3D MOF. The catalytic activity of catalyst with 2D MOF can be significantly improved due to its exposure to more active sites. In recent years, the two-dimensional metal organic framework has received considerable attentions because of its potential applications. In this review, two kinds of synthesis methods of 2D MOF including top-down and bottom-up, are introduced. The 2D MOF is fabricated by the role of external forces to exfoliate the block MOF in top-down method, while 2D MOF nanosheets directly synthesize through metal clusters and ligands in the bottom-up. It is found that the excellent performance of 2D MOF is related to topology network structure, and different structures exhibit different porosity and stability. Then, the application of MOF nanoplates in catalysis, sensing and gas separation are described according to its properties. Finally, the prospect of 2D MOF is given.

Abstract:Aiming at the problem of insufficient research on the deformation characteristics of the pile foundation of the excavation near the pile-plank subgrade，the deformation control of the pile-plate structure pile foundation by the excavation of the foundation pit was studied based on a deep foundation pit project of Shanghai Airport Line. The finite element method was used to analyze the deformation law of the roadbed. Based on the deformation of the pile foundation，the influence zoning was carried out，and a method for calculating the allowable limit value of the deformation of the envelope structure based on the pile deformation control was proposed. The research results show that：The horizontal displacement curve of the pile foundation near the foundation pit is arched，the horizontal displacement of the entire pile body is large，and the maximum horizontal displacement of the pile foundation is 5.66 mm. The horizontal displacement curve of the pile foundation far away from the foundation pit is cantilever-shaped，and the maximum horizontal displacement occurs at the top of the pile，and the horizontal displacement of the deep pile is small. The affected area of pile foundation deformation under excavation depths of 9.5，17.4 m，and 25.5 m is divided into Zone A (danger zone)，Zone B (warning zone)，and Zone C (safety zone)，and engineering protection measures are proposed for each zone. A method for calculating the allowable limit of the deformation of the envelope structure under the control of pile foundation deformation is proposed in accordance with Technical Code For Foundation Pit Engineering.

Abstract:Accurately predicting the amount of construction waste is of great significance for carrying out the recycling treatment of construction waste and guiding the government to formulate relevant policies. However, the lack of reliable forecasting methods and historical data makes it difficult to predict the construction waste in the long- or short-term planning. On the basis of the univariate time series data of limited sample points, this paper puts forward a short and long memory(LSTM) time series prediction method to effectively solve the problem of construction waste prediction, which involves network structure with dropout layer and the algorithm of network training and prediction process. Taking Shanghai as a case，compared with other time series prediction models, numerical experiments were conducted to verify the effectiveness and accuracy of the LSTM prediction model in the filed of predicting construction waste generation.

Abstract:The Haide tunnel needed to pass through a large number of caves in the construction, and encountered the problems of over limit deformation and collapse caused by heavy rainfall. Based on FLAC3D, an unsaturated seepage module considering rainfall infiltration was developed in this paper. Orthogonal numerical experiments considering three factors of filling medium, karst caves’ location and rainfall intensity were designed. Combined with measured deformation and pressure data, the tunnel’s mechanical characteristics were studied. The conclusions show that the karst caves with different filling medium have an effect on the tunnel deformation, which is mainly caused by the change of pore pressure due to the difference of medium’s gravity, permeability and water holding capacity. The spatial position of the karst cave causes the spatial difference of the mechanical properties of the tunnel. The caves near the arch have a restraining effect on the deformation and stress of the tunnel’s arch, while the caves near the side wall increase the deformation and stress of the lower section of the tunnel. According to the displacement release coefficient, the existence of these caves increases the spatial effect of tunnel construction. Heavy rainfall supplies the groundwater, which then increases the magnitude of the ground stress in a short period of time, finally brings additional bearing capacity to the tunnel structure. When the rainfall enters the well -permeable soil in the cave, the influence of the cave on the tunnel will also be changed.

Abstract:A large number of cracks appear in the chamfering positions of webs and baseplates in the middle span of a long-span skew variable cross-section wide width continuous box girder bridge after 6 years operation, and they continue to crack after reinforcement. In order to get the exact cause of cracks in the box girder, a three-dimensional solid finite element model simulating the construction process is established based on ANSYS software. The results show that it is not accurate to analyze the wide skew beam bridge with significant spatial effect only by using the member system beam element. The web thinning, the reduction of vertical prestressed reinforcement and the spatial effect can easily lead to cracking in the chamfering position of web and floor and the single box single chamber section is not suitable for 19.3 wide bridge.

Abstract:To deal with the situation with given traffic demand generated from origins and partial observed link flows, a bi-level programming model of estimation of the OD demand is proposed. The upper level was designed to minimize the difference between the assigned link flows and the observed link flows. To properly describe the route choosing behaviors of travelers, the user equilibrium traffic assignment model was adopted in the lower level model. A proper algorithm was designed for the upper level model by embedding an approximate FrankWolfe algorithm into the augmented Lagrange multiplier algorithm. To obtain the joint solution of the bi-level model, the algorithm of lower level model with given OD demands should be called repeatedly to obtain the assigned link flow. The numerical example verified the effectiveness and efficiency of the new model and algorithm. The research result not only extends the application setting of the existing theory of estimation of OD demands, but also provides new ideas and methods to formulate and analyze the related problems.

Abstract:To certain extent, the express and local train mode of the municipality rail transit is conducive to improving passenger service level and the efficiency of municipality rail transit and reducing enterprises’ costs, but there is a multi-objective problem for determining the operation scheme with the express and local train mode. This paper constructed a comprehensive evaluation system of the operating schemes from the perspective of passengers and enterprises, and designed a comprehensive evaluation model for the operating scheme’s priority degree. The principle of extenics was used to establish the matter element set of the operating scheme, and the dynamic measurement conditions of each evaluation index were given; What’s more，the combined weight method was used to determine the comprehensive weight of each evaluation index; then the degree of compliance of each scheme was olesoribed according to the calculated correlation degree; finally, the optimal scheme suitable for the initial, medium term was given based on the results of priority degree.

Abstract:Considering the high-density characteristics of urban road traffic, the impact of lane-changing process is distinguished from the acceleration change caused by traffic density after lane-changing. A traffic flow dynamics equation considering the impact of lane-changing process is proposed. This method first converts the reduction coefficient of the Laval model with the nature of lane-changing competition and balance into the difficulty of lane-changing, and then through the comparison of the difference calculation, the calculation method of the lane-changing influence item is given when the traffic flow is not smooth. The results show that the dynamic equation can describe the traffic flow behavior under high-density conditions, and express the viscosity of the traffic flow caused by the target lane and the departure lane.

Abstract:In order to meet the development trend of green civil aviation and enrich，expand the research contents of airport passenger service quality，this paper introduces the concept of “Green Airport”，constructs the evaluation model of high-level airport passenger green service quality by referring to the original airport service quality evaluation model，and forms the airport passenger green service quality evaluation scale. The results show that the model has good fitting degree and the scale has high reliability and stability，which can be used to evaluate the airport passenger green service quality appraisal based on passenger perception.

Abstract:Aiming at the conflict between right turning vehicles and straight bicycles at signalized intersections, the behavior characteristics of vehicles and bicycles were analyzed. According to the initial release characteristics of green light of non-motor vehicles, an expansion model was established, and the expansion degrees of different signal types were compared. From the perspective of driving psychology, the driving style of vehicles and bicycles was analyzed. Through video capturing and image processing, the average speed of right turning vehicles passing through the intersection under the influence of bicycles at the intersection of Shanghai Kongjiang Road and Longchang Road was extracted. K-means clustering analysis was used to classify drivers into cautious, robust and radical type for the speed of right turning vehicles passing through the conflict zone, and the speed and trajectory of right turning vehicles under the influence of straight bicycles were analyzed.

Abstract:With the rapid development of China’s civil aviation industry, the position of hub airports in civil aviation has been improved. However, the classification of hub airports is undefined, with strategic planning insufficient and the functional orientation seriously homogenized, which makes the vicious competition between airports fierce. Therefore, hub airports are classified according to the collaborative development to achieve differentiated and hierarchical development of various airports. This paper took the 40 hub airports mentioned in the National Civil Airport Layout Plan(2017) as research objects, and the classification problem was solved by methods of three-stage and super-efficiency DEA, clustering analysis and BP neural network. The gradient classification of hub airports was carried out, and the collaborative development strategy based on functional orientation was proposed to promote the sustainable development of aviation industry.

Abstract:A portable emission measurement system (PEMS) was used to perform a real driving emission(RDE) test on three China 6 light-duty vehicles to study the impact of cold starting on real road driving on CO and NO_x emissions. The CO₂ moving average window method was used to process the test data of these vehicles, and compare the contribution rate of CO and NO_x emissions and the mileage of the road section in the urban area and the whole process at different coolant temperatures. It is found that the CO and NO_x emission factors including cold start are 10.45%~53.12% and 8.91%~38.74% higher than those of without cold start for gasoline vehicles, and 62.60%~96.67% and 2.11% ~ 4.79% higher for diesel cars; Lower engine temperature leads to serious CO emissions from both gasoline and diesel engines, and low coolant temperature has a certain inhibitory effect on diesel engine NO_x emissions. It is recommended that the follow-up emission regulations pay more attention to the cold start emissions of the RDE test.

Abstract:In order to find the optimal path for the intelligent inspection robot, the traditional ant colony algorithm was improved. The A* algorithm was used to improve the ant’s path-finding rules, and multiple smooth iterations were performed on the found path, which filled the defects that the traditional A* algorithm easy to fall into a "trap". At the same time, the purpose of smoothing the path and shortening the distance was achieved, the pheromone processing method of ant colony was optimized, and the double pheromone strategy was introduced to get the optimal path. Compared with the traditional ant colony algorithm, the improved algorithm can avoid obstacles accurately, and has a faster and better ability to search for the optimal path.

Abstract:The residual stress of aluminium-based composite coating by laser cladding was simulated by the finite element method with ANSYS. The finite element model of composite coating was established. The effects of the in-situ Al-Fe-Si content in the Al matrix coatings by laser cladding on the temperature field and residual stress was discussed systematically. The results show that the temperature along Z-axis increases gradually with the increase of the in-situ Al-Fe-Si content, and the amplitude of temperature rising gradually decreases with itsbeing closer to substrate. However, the X-direction stress and Von Mises stress on the coating surface first decreases and then increases, and the Y-direction stress on the coating surface gradually decreases, while, the shear stress at the interface changes little. Therefore, when the in-situ Al-Fe-Si content by laser cladding is about 0.4, the residual stress of aluminium-based composite coating is the minimum.

Abstract:A model of hybrid membrane-in cavity is proposed, in which a two-level quantum dot is coupled to the cavity field and the membrane mechanical oscillator at the same time. The bidirectional coupling of quantum dots with cavity field and mechanical oscillator enhances the nonlinear characteristics of the system, which improves the squeezing of the transmitted field and the spontaneous cooling ability of the mechanical oscillator. The results show that the squeezing degree of the transmitted field can be over 90%. With the aid of the quantum dot-mechanical oscillator coupling, an additional squeezing of at least 2% can be obtained. The temperature of the mechanical resonator can be cooled down from room temperature to tens of millikelvin. These operations can be easily controlled by adjusting the power or frequency of the pump light.

Abstract:Aiming at the high precision and real-time requirements of the data acquisition system in the field of power quality detection， project design of a multi-channel data acquisition system based on ZYNQ-7000 and AD7606 is proposed. The FPGA part of ZYNQ is used to realize the collection and control of the system. The ARM part completes data transmission， storage and result display. System uses AXI4 high-speed communication， DMA-SG high-speed data transmission mode， and DDR3 high-speed storage to achieve high-speed acquisition of voltage and current signals. Experimental results show that the acquisition accuracy of the system can reach 0.02% . The system has the characteristics of small size， low power consumption， high accuracy， strong real-time performance and strong stability.

Abstract:With the rapid development of Internet technology, multimedia data of different view have grown exponentially, and people have been unable to satisfy the original single-modal data retrieval methods such as image retrieval. Cross-modal retrieval has became more and more important in information retrieval field. Aiming at this task, a cross-modal retrieval method for double-branch network structure by increase the attention mechanism of sentence-dependent phrases is proposed. The paper appies the CNN model to extract image features, and obtains the dependency segments of text based on syntactic structure analysis, and designs the original double-branch network structure model which embeds the attention mechanism to learn the weight distribution of each dependent segment, so that the feature representation of the text can be more focused on key sentence segment features. The experimental results show that the proposed method has better performance in the retrieval accuracy evaluation than other methods, and verify the effectiveness of the algorithm.

Abstract:This paper makes a statistical analysis of the technology contract transactions in Jiangxi Province in recent years, and analyzes the shortcomings of Jiangxi’s technology market development from the perspectives of technology trading platform, technology market management system, technology transfer intermediary service ability and high-quality talent support. It puts forward some effective ways to improve the service function of the online technology market, strengthen the guidance and management of the technology market, increase the effective supply of high quality scientific and technological achievements, and increase the cultivation of technical intermediaries and the investment of talents.