2016 volumne 37卷 Issue 06
Dai Pinqiang1,Song Lairui2,Cui Zhixiang3,Wang Qianting3
Abstract: Chitosan ( CS)/poly ( vinyl alcohol) ( PVA) composite fibers were fabricated by electrospinning in this study. The influences of material formulation and formed time on the viscosity,electrical conductivity and the morphology, average diameter, diameter distribution of CS/PVA composite fiber were investigated. The re-sults showed that, the introduction of CS could increase the viscosity,electrical conductivity of CS/PVA blend solution. And the viscosity of blend solution decreased with the increase of formed time. In addition, the more CS content was, the smaller diameter of CS/PVA composite fiber would be. The fiber-forming capacity of CS/PVA blend solution decreased dramatically as the solution formed time increased.
Wang Wen1,Hu Haoliang1,He Shitang1,Pan Yong2,Zhang Caihong3
Abstract: In view of the current situation that the traditional methane sensor technology is difficult to imple-ment the field detection and monitor on methane gas, a novel room-temperature SAW methane gas sensor coa-ted with cryptophane-A sensing interface is proposed by utilizing the supermolecular compound cryptophane-A’ s specific clathration to methane molecules. The sensor was composed of differential resonator-oscillators with excellent frequency stability, a supra-molecular CrypA coated along the acoustic propagation path, and a frequency acquisition module. The supramolecular CrypA was synthesized from vanillyl alcohol using a three-step method and deposited onto the surface of the sensing resonators via dropping method. Fast response and excellent repeatability were observed in gas sensing experiment, and the estimated detection limit and meas-ured sensitivity in gas dynamic range of 0 . 2% ~5% was evaluated as ~0 . 05 % and ~184 Hz/%, respec-tively. The measured results indicated the SAW sensor was promising for under-mine methane gas detection and monitor.
Hu Xiaobing, Xie Zhenfang, Xie Ji, Xie Lili, Zhu Zhigang
Abstract: Micro/Nano-particles of CuO were prepared with hexamethylenetetramine template. The composi-tion and morphology of the product were characterized by SEM and X-ray diffraction. The synthetic powder was prepared as sensitive membrane, and its gas sensitivity was studied with a static gas distribution method. The results indicated that the uniform copper oxide powders was synthesized at the 110℃, and the molar ratio be-tween copper nitrate and hexamethylenetetramine was 1∶45. The spindle structure was around 1~2 μm, and was composed of 100 nm nanoplates. The sensor had better selectivity with CH3 COCH3 and H2 S. Copper ox-ide showed good selectivity to hydrogen sulfide and its sensitivity had a certain degree of improvement after fur-ther doping 0. 25% ~1. 25% noble metal catalyst Pt.
Fan Chunzhen1,Zang Huaping2,Mu Kaijun2
Abstract: Bimetallic nanoparticles exhibied optical properties that differ significantly from those of the bulk material due to hybrid surface plasmon resonance. With the quasi-static approximation, the behavior of the light propagation was investigated. Resorting to the Bruggernan theory, the extinction coefficient, absorption coefficient, reflection, transmittance and refraction were theoretically investigated. Our results showed that by tuning the volume fraction of the metallic nanoparticles, its resonant peak could be tuned as accordingly. This calculation method can significantly improve the computing efficiency.
Chen Weihang1,Li Yien1,Zhang Jie1,Jiang Yuanli2,Wang Xunqiu1
Abstract: In this study, isobaric vapor-liquid equilibria ( VLE) data for the ternary system of Ethyleneglycol, 1,4-Butylene glycol and Diethylene glycol were measured at 6. 67 kPa. The experimental data were correlated by the widely used NRTL, UNIQUAC, and Wilson models, and the results showed that the maximum average relative error between the experimental data and the predicted data was 5 . 3262%, which could meet the re-quirement of separation engineering.
Shi Suyu1,Wang Lina1,Xu Wenzhong2,Zheng Guoqiang2,Shen Changyu2
Abstract: The high density polyethylene ( HDPE ) parts with two different molecular weights were prepared with micro-injection molding. The dependence of microstructure and mechanical properties of samples with dif-ferent molecular weight were examined. Tensile test indicated that the increase to 77. 5% in tensile strength was achieved for HDPE parts with higher molecular weight. At the same time, the toughness of HDPE parts were enhanced about twice as compared with that of lower molecular weight. In this study, microstructure characterizations, including differential scanning calorimetry ( DSC) , wide-angle X-ray diffraction ( WAXD) , small-angle X-ray scattering ( SAXS) and scanning electronic microscope ( SEM) were emplayed/conducted to investigate the variations of microstructure and further established the relationship between microstructure and mechanical properties. It suggested that the increased molecular and crystalline orientation led to the reinforce-ment. Formation of more shish and shish-kebab structure was in favor of the enhanced strength as well. The notable improvement of toughness in the higher molecular weight parts should be ascribed to formate a strong physical crosslinking network.
Deng Yadong1,Zhang Kun1,Jin Dexian2
Abstract: In order to design a simple and reliable lifting hydro-cylinder bracket structure, the topology optimi-zation mathematical model based on the Variable Density Method was established by the volume fraction as constraint conditions and the weighted compliance as objective function. By means of linear approximation method, analyzed the force condition of the lifting hydro-cylinder bracket of a road sweeper with composite trash bin in the dumping process and determined lifting starting condition and maintenance condition as the main force conditions for the design of the lifting hydro-cylinder bracket. The topology optimization design of the lifting hydro-cylinder bracket was carried out by using the Variable Density Method. Considering the relia-bility of manufacturing process, a three dimensional model of the lifting hydro-cylinder bracket was established based on the topology optimization results, and the linear static analysis of the model was carried out. The final results showed that the lifting hydro-cylinder bracket designed by the variable density method had the advanta-ges of simple structure, small occupied space, the largest stress and maximum strain in reasonable range and met the requirements of the application.
Zhao Jiangming1,Qiu Guolin2,Zhang Haixia3
Abstract: Based on the pyroelectric effect of polyvinylidene fluoride ( PVDF) film, a new micro pyroelectric generator was designed. The basic structure and working principle of the generator were introduced, corre-sponding experiments were completed and output characteristics of the generator under different temperature differences were analyzed through finite element method. The experimental results showed that the output volt-age increased with the increase of the matched resistance and the output current was vice versa. The maximum instantaneous output power under 20 ℃ and 40 ℃ temperature difference was 208 μW and 475 μW, respec-tively. The simulation results show that with the increase of the temperature difference, the changing rate of temperature with time increased. The respective open-circuit voltage under 20 ℃ and 40 ℃ temperature difference was 689 V and 1380 V. The simulation and experiment proved that the generator could be used as an effective means of energy harvesting, which would give guidance for further research in the future.
Li Jingli, Xu Zhigang
Abstract: To effectively generate novel and useful product ideas, a new method based on theory of the inven-tion problem solving ( TRIZ) , the future reality tree ( FRT) and fuzzy evaluation was presented. The aims of the proposed method were:1 ) to identify potential problems through the product function model;2 ) to ab-stract potential problems and generate novel product ideas by means of the theory of invention problem solving;3 ) to develop an effective evaluation method and clearly describe the goal of product innovation using future reality tree as preliminarily evaluation tool;and, 4) to get promising product ideas with fuzzy evaluation tech-niques. Finally, the innovative design of frog ramming machine was used to illustrate the feasibility of this new method.
Han Jie, Wu Yanzhao, Chen Lei, Hao Wang, Zhang Qianlong
Abstract: Considering incomplete vibration information that leading to poor consistency of predictive results, single-channel prediction method cannot realize accurate prediction of machine fault. While by obtaining spec-tral structure with unique characteristics, full vector spectrum ( FVS) can well make up for the deficiency of single-channel. Further the prediction method of FVS-ARMA model was proposed in this paper, which com-bined ARMA model with full vector spectrum technology. It was applied to predict the mechanical vibration strength. Experiments showed that prediction results of this method were identical to the practical effects.
Qian Zhendong1,Zhang Meng1,Xu Jing2
Abstract: After cracks appear on steel bridge deck epoxy asphalt concrete pavement, the water would seep in-to cracks which would lead to crack propagation. This paper studied the impact of hydrodynamic pressure on the propagation of steel bridge deck epoxy asphalt concrete pavement crack. ABAQUS was utilized to build a model of steel bridge deck epoxy asphalt concrete pavement with crack. The J integral of pavement crack un-der different temperatures, different pavement crack widths, different pavement crack lengths, different pave-ment crack depths and different number of pavement cracks were calculated. The impact of hydrodynamic pressure on steel bridge deck epoxy asphalt concrete pavement crack propagation was discussed. The results indicated that when hydrodynamic pressure increased, the J integral of pavement crack tip increased, and the effect of hydrodynamic pressure on crack propagation was more obvious. When the temperature was within the range of 0℃ to 30℃, the increase of temperature would lead to the increase of J integral of pavement crack tip and the effect of hydrodynamic pressure on crack propagation would be more obvious. The effect of hydrody-namic pressure on the crack propagation changed obviously under different crack lengths and widths, while the effect of hydrodynamic pressure on the crack propagation changed unobviously under different crack depths and different number of longitudinal crack. Pattern cracking was easy to propagate under the same hydrodynamic pressure.
Zhang Tao1,Le Jinchao2,Zhang Junran3
Abstract: A series of the soil-water characteristic curve ( SWCC) tests for Yudong silt with different compac-tion degree and wetting-drying cycles were conducted by the pressure plate apparatus with the GCTS model. The test results showed that the SWCC curves had obvious hysteresis phenomenon during the drying and wet-ting cycles when the value of the suction was less than 100 kPa. While the value of the suction was greater than 100 kPa, the SWCC hysteresis phenomenon was not obvious. The SWCC was expressed by the relations between suction and water content, the SWCC curves have a shift to the bottom and left trend with the increase in the compaction degree and drying-wetting cycles. When the SWCC is expressed by the relations between suction and saturation, the SWCC curves had a shift to the top and right trend with the increase in the compac-tion degree, while the SWCC curves had a shift to the bottom and trend with the increase in the wetting-drying cycles. The Lsqcurvefit function of the Matlab was adopted for fitting of the SWCC curves to get the fitting pa-rameters of the Van Genuchten model. Through the relations between the fitting parameters and the compaction degree or drying-wetting cycles, the practical methods were proposed to predict the Yudong silt SWCC with different compaction degree or drying-wetting cycles.
Wang Heng; Chen Tingguo
Abstract: According to the elastic analysis of rectangular hole castellated beams by using the finite element software ANSYS, the stress distribution of castellated beams was studied, which mainly included normal stress and shearing stress distribution of pier cross section, normal stress distribution of pier longitudinal section and normal stress distribution of beam bridge. In addition, the factors affecting the normal stress and shearing stress distribution of the center of pier cross section were studied in detail, which contained span-depth ratio, width-depth ratio, length-depth ratio and space-depth ratio. The research could provide reference for engineer-ing design.
Zhang Junfeng, Gao Jianli
Abstract: For long-span space truss structures, it was very important to accurately simulate the nonlinear performance. Based on the increment of UL method of differential equation, the stiffness matrix of the space truss considering geometric nonlinear was deduced. The high order nonlinear truss element was developed in the OpenSees platform. The realization of the element, the static and dynamic calculation of TCL command flow and the nonlinear algorithm of iterative process were put forward. Several kinds of truss structure under the action of nonlinear static and seismic nonlinear dynamic analysis were carried out. And the results showed that the element could reflect the strong nonlinear behavior of trusses.
Zhao Juan, Li Bei
Abstract: This paper aimed to explore the concrete carbonation problem under climate change, based on birdge connecting Zhengshao Highway to Hanghai Road project,by simulating climate boundary models in high emission situation and low emission situation of Zhengzhou according to the latest research report by Intergov-ernmental Panel on Climate Change. The model predicted carbonation life of beam and pier by setting up de-velopment trends of temperature, humidity and CO2 concentration in the next 100 years accor models. Com-pared with carbonation life calculated by constant climate parameters. The results showed that climate change would affect bridge carbonation process in central plains to a certain extent. Compared with low emissions situa-tion,carbonation life of beam and piers would be shorten about 13% in high emissions situation.
Lu Peng, Zhang Lia, Huang Shilei, Li Qihang, Zhang Wei
Abstract: The focus question of video abnormal behavior detection was how to illustrate the behavior correctly through analysis of huge amounts of data. A new algorithm was proposed based on visual sparse overcomplete representation mechanism to extract local effective information about the interest points in the video of specific scenario, which could improve the efficiency of data processing. Firstly, the algorithm extracted the local spa-tial temporal interesting points ( STIP) in training samples. At the same time it calculated the local spatial temporal characteristics. Then it put the characteristics into sparse overcomplete representation model to get a set of sparse matrix after training. Finally, it reconstructed the query video using the aforementioned matrix to detect abnormal behavior through the reconstruction error of local spatial temporal characteristics. In addition, the updated algorithm of sparse matrix function for different videos was proposed. Experiment results on stand-ard database showed that our algorithm could detect abnormal behavior effectively and with higher accuracy and lower false alarm.
Li Cailin, Chen Wenhe, Wang Jiangmei, Tian Pengyan, Yao Jili
Abstract: Cliff and steep slope are important landscape elements of topographic map, and these elements play a very important role in the construction of the ecological environment and prevention of geological disasters, etc. However, it is unfavorable to observe and process data because of vegetation occlusion on cliff. In this paper, we present a cliff vegetation filtration method based on the principle of surface orthographic projection. Firstly, transform the original three dimensional point cloud of cliff to the spatial cartesian coordinate system, whose xy plane is the cliff face and z-axis is perpendicular to the direction of the cliff surface. Then the grid on the xy plane is divided to establish local grid Digital Terrain Model ( DTM) by fitting surface, and the vegeta-tion points can be extracted through setting a reasonable distance threshold. Finally, after inverse projection transformation, cliff rocky points preserved are mapped to the original spatial coordinate system. The experi-mental analysis using actual cliff point cloud data shows that the cliff point cloud vegetation filtering method based on the surface orthographic projection is feasible and effective.
Mu Xiaomin; Liu Yue; Li Shuangzhi; Zhang Jiankang
Abstract: A novel semi-blind channel estimation was devised to jointly estimate the channel matrices of all links in a three-hop multiple-input multiple-output relay system. A PARAFAC and a PARATUCK2 tensor model of the received signal were constructed, and the proposed algorithm used a two-stage iterative fitting al-gorithm for tensor model. The ALS algorithm was used to fit the PARAFAC tensor model in the process of esti-mating the compound channel matrix. Then the TALS algorithm was used to fit the PARATUCK2 tensor model in the process of extracting all the sub-channel matrices. The proposed algorithm could loose the limitation on the number of antennas at the destination node. Moreover, compared with existing methods, the proposed al-gorithm could avoid error propagation as well as improve the spectral efficiency with few pilots. Numerical ex-amples demonstrated the effectiveness of the proposed algorithm.
Liu Shuru, Zhang Qikun, Gan Yong
Abstract: The frequent inter-domain or intra-domain movement of vehicles in vehicular networks may lead to large binding update costs and packet delivery costs. In order to solve this problem, an improved pointer for-warding scheme(EPF-HMIPv6) was developed in thwas paper. The scheme was based on the existing pointer forwarding scheme in cellular networks, and the routing of packets was optimized. To evaluate the performance of the proposed scheme, Analytical expression we were derived for binding update cost, signaling overhead caused by HMIPv6 and EPF-HMIPv6 handovers. The simulation results showed that the proposed scheme was better than the existing mobility management protocols in vehicular networks.
Wang Huiliang, Wu Zening, Guo Xi, Guo Ruili
Abstract: Emergy analysis of agriculture ecosystem was a hot topic of academic group nowadays. Concerned with the loss of ecological environment, an improved emergy analysis of agriculture ecosystem was proposed based on the calculation of agriculture ecological environment loss. Taking Zhengzhou as the example, this pa-per discussed how to apply it to practice. The results showed that the average ecological environmental loss of Zhengzhou from 2000 to 2009 was 2. 44 × 1021 sej,accounting for 15. 47% of economic emergy out of agricul-ture ecosystem. The method was rational for its conclusion was in agreement with the domestic and internation-al research results,the proportion of agricultural externality to agricultural income was 6% ~30%. Given the agriculture ecological environment loss subtracted from economic emergy output, the average Net emergy yield ratio EYRL fallen from 2. 86 to 2. 45, and the average emergy sustainable indices ESIL from 1. 19 to 1. 01, in-dicating that the influence of ecological environmental loss on eco-efficiency and performance of system was significant.
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