Editor in chief：朱立光
International standard number：ISSN 1008-1542
Unified domestic issue：CN 13-1225/TS
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2015, 36(2):111-117. DOI: 10.7535/hbkd.2015yx02001
Abstract:Eliminating the negative effect of gear backlash on transmission precision so as to achieve precise motion transformation remains a problem to be solved in the field of precision transmission. To date， optimization of manufacturing process， new transmission structure and control system are mainly used to solve the above scientific problem， however， the new transmission structure is undoubtedly the best method compared with the methods above based on the analysis of advantages and disadvantages for various methods. In doing so， this paper originally proposes a type of transmission， an anti-backlash end face engagement worm gearing， with certain advantages of no-backlash， high precision and high operating efficiency over other gears and gear systems.
2015, 36(2):118-125. DOI: 10.7535/hbkd.2015yx02002
Abstract:Focusing on auto control of parking brake system of the medium and heavy duty vehicles, the key problems are studied including the system design and control strategies. The structure and working principle of the parking brake system of the medium and heavy duty vehicles are analyzed. The functions of EPB are proposed. The important information of the vehicle are analyzed which could influence the EPB system. The overall plan of the pneumatic EPB system is designed, which adopts the two-position three-way electromagnetic valve with double coil as actuator. The system could keep the vehicle parking brake status or parking release status for a long time without power supply. The function modules of the system are planned, and the control strategies of automatic parking brake and parking release are made. The experiment is performed on a medium-sized commercial vehicle which is experimentally modified. The overall plan of the pneumatic EPB system and the automatic parking function are proved through real vehicle tests.
2015, 36(2):126-133. DOI: 10.7535/hbkd.2015yx02003
Abstract:This paper first outlines the worldwide oil and gas pipeline laying situation by 2013 and industrial applications, the working characteristics and advantages of orbital pipe welding robots using the gas metal arc metal(GMAW). Then the classifications of commonly used welding seam tracking sensors are comprehensively introduced. The sensor working principles, advantages and disadvantages and the application situation in pipeline welding are analysed in details. The studies show that arc sensors and visual sensors have many advantages such as good real-time characteristic, informativeness and high tracking precision, and are most widely used in pipeline welding. Using single sensor in different process can limit the tracking precision easily, but a system with multiple sensors will greatly improve the tracking precision in oil and gas pipeline welding. A system using visual sensor and arc sensor has been used in the gas field pipeline welding in Japan and a good effect has been achieved. Finally the conclusion is drawn that suitable seam tracking sensor should be chosen according to the process features and methods, and using a variety of sensors can improve the welding seam tracking precision, which will become the focus of future researches.
2015, 36(2):134-143. DOI: 10.7535/hbkd.2015yx02004
Abstract:By defining appropriate linear space and norm, giving the appropriate operator, using the contraction mapping principle and krasnoselskii fixed point theorem respectively, the existence and uniqueness of solutions for boundary value problem of fractional order impulsive differential equations systems are investigated under certain condition that nonlinear term and pulse value are satisfied. An example is given to illustrate that the required conditions can be satisfied.
2015, 36(2):144-149. DOI: 10.7535/hbkd.2015yx02005
Abstract:A planar point set X is called a k-distance set if there are exactly k distinct distances defined by every two points in X, and the longest distance is called diameter D. The set of the endpoints of all diameters is denoted by XD . Let m=m(X)=|XD| be the number of elements of XD, and the diameter graph DG(XD) be all diameters in X. There are many results on determining the value of g(k) when k≤6, where g(k) is the number of points of the largest point set having k distinct distances. We consider planar point sets for the case of k≥7. Firstly, we perform an analysis on the degree value d(v) of all vertices in k-distance DG(XD) for m=|XD|=2k-1, and obtain that d(v)≤2. Based on this result, we research the case of 7-distance. We get XD=R15-3 when the 7-distance sets DG(XD)=P10∪P2. The result provides a theoretical foundation for further discussions on 7-distance sets.
2015, 36(2):150-156. DOI: 10.7535/hbkd.2015yx02006
Abstract:This paper investigates the problem of robust H∞ guaranteed cost control for non-linear uncertain switched singular systems with multiple time-delay. Nonlinear is considered to be norm bounded and the systems are regular and impulse free. A sufficient condition for existences of robust H∞ guaranteed cost controller is given by the linear matrix inequalities (LMI) at the Lyapunov function and switching rule. It is shown that the closed-loop systems are asymptotically stable. Finally, the results are validated and advantage, through a given example.
2015, 36(2):157-162. DOI: 10.7535/hbkd.2015yx02007
Abstract:Due to the larger workload in the implementation process and the poor consistence between the test results and actual situation problems when using the transmission line pulse (TLP) testing methods, a modeling method based on the recurrent neural network is proposed for EMP response forecast. Based on the TLP testing system, two categories of EMP are increased, which are the machine model ESD EMP and human metal model ESD EMP. Elman neural network, Jordan neural network and their combination namely Elman-Jordan neural network are established for response modeling of NUP2105L transient voltage suppressor (TVS) forecasting the response under different EMP. The simulation results show that the recurrent neural network has satisfying modeling effects and high computation efficiency.
2015, 36(2):163-169. DOI: 10.7535/hbkd.2015yx02008
Abstract:In order to investigate the terminating load voltage of the unshielded multi-core cable coupled with lightning electromagnetic pulse(LEMP), we simulate LEMP within the bounded-wave transmission line which is input with a lightning surge signal produced by WU-800-type MARX generator and conduct the relevant experiments towards multi-core cable lines radiated by LEMP. We can get the respond laws of induced voltage of the load by changing the length of unshielded multi-core cable, angles between LEMP and cable, waveforms of LEMP as well as cable terminal loads including linear and non-linear loads. Results show that the amplitude of induced voltage is mainly determined by rising part of electromagnetic field waveforms and the pulse width has little effect on the induced voltage. The respond amplitude and the respond frequency are obviously affected by the length of cable. The polarization direction of the electric field has a great impact on the amplitude of terminal response, but it does not change the waveforms of the induced voltage. With the termination of test side increasing, the induced voltage is gradually increased, but the load in the other side has no effect on the induced voltage.
2015, 36(2):170-175. DOI: 10.7535/hbkd.2015yx02009
Abstract:Wet digestion is used as the pre-treatment technology for the electrochemical detection of heavy metals in food, and the complete wet digestion condition of food sample is optimized by electrochemical experiments. The results show that the experimental samples can be digested completely using the Nitric acid-hydrogen peroxide system and is not pre-digested after adding 10 mL nitric acid at 120~140 ℃ and adding 10~15 mL of hydrogen peroxide during the heating process. The correlation coefficient of electrochemical detect is 0.99 for digestion solution of the samples， and the recovery of standard addition is 82%~115%. Wet digestion as a pre-treatment technology of food samples, It can digest sample fully and meet the requirements of electrochemical detection.
2015, 36(2):176-181. DOI: 10.7535/hbkd.2015yx02010
Abstract:To establish the SPE-HPLC method for determining content of brucine in Fengshi Maqian tablet, the cation exchange solid phase extraction column is used to purity the samples. By using PXC cation exchange solid phase extraction (SPE), the HPLC column used in the experiment is C18(250 mm×4.6 mm，5 μm)， the mobile phase consists of acetonitrile-001 mol/L sodium heptanesulfonate and 0.02 mol/L KH2PO4 mixed half and half (adjusting pH to 2.8 with 10% phosphoric acid) (volume ratio of 21∶79)， the flow rate is 1.0 mL/min, the detection wavelength is 262 nm， and the column temperature is 30 ℃. The content of brucine determined by SPE-HPLC method has good linear relationship with the peak areas when their concentration is at 40~60 μg/mL (r=0.999 3). The range of recovery rates of Brucine are 99.6%~101.0% (RSD=104%).This method is simple and accurate with good reproducibility， and it can be used to determine the content of brucine in Fengshi Maqian tablet.
2015, 36(2):182-187. DOI: 10.7535/hbkd.2015yx02011
Abstract:Rare earth-β-diketone ligand complex luminescent material has stable chemical properties and excellent luminous property. Using europium oxide and (γ-NTA) as raw materials, novel rare earth-β-dione complexes are synthesized by solid state coordination chemistry. The synthesis temperature and milling time are discussed for optimization. Experimental results show that the suitable reaction situation is at 50 ℃ and 20 h for solid-phase synthesis. The compositions and structures of the complexes are characterized by means of elemental analysis, UV-Vis and FTIR methods, and the phase stability of the complex is determined by using TG-DTA technique. It is proved that preparation of waterless binary rare earth complexes by the solid phase reaction method results in a higher product yield. The fluorescence spectra show that between Eu (Ⅲ) and γ-NTA, there exists efficient energy transfer, and the rare earth complexes synthesis is an excellent red bright light-emitting material with excellent UV excited luminescence properties.
2015, 36(2):188-194. DOI: 10.7535/hbkd.2015yx02012
Abstract:With the rapid development of social network, people can present or share their opinions and emotions on the micro-blog, and as a result, large amount of blog texts and emotional information of different topics are produced. As the traditional text mining algorithms cannot deal with these blog texts with fractional contents and different personal emotions effectively, this paper presents a novel weighting computation approach based on the key characters of micro-blog posts to get the dynamic interests of bloggers on different times. Furthermore, based on the emotion classification, the emotion transition tendency analysis can also be implemented. Experimental results show the feasibility of the presented approach.
2015, 36(2):195-202. DOI: 10.7535/hbkd.2015yx02013
Abstract:Aiming at the flight path project in low complicated airspace, the influence of terrain conditions and surface threatening to aircraft flight are studied. Through the analysis of digital map and static threat, the paper explores the processing method of the digital map, and uses the Hermite function to process the map smoothly, reducing the searching range of optimal trajectory. By designing the terrain following, terrain avoidance and the way of avoiding a threat, the safety of aircraft can be guaranteed. In-depth analysis of particle swarm optimization (PSO) algorithm realizes the three dimensional paths project before the aircraft performs a task. Through simulation, the difference of the maps before and after processing is shown, and offline programming of the three dimensional optimal path is achieved.
2015, 36(2):203-209. DOI: 10.7535/hbkd.2015yx02014
Abstract:The issue of the aerodynamic noises from wind turbine blades affecting the surrounding residents life begins to attract researcher’s attention. Most of the existing researches are based on CFD software or experimental data fitting method to analyze the aerodynamic noises, so it is difficult to adapt the demand to dynamic analysis of the aerodynamic noises from wind speed variation. In this paper, the operation parameters, the inflow wind speed and the receiver location are considered, and a modified model to calculate aerodynamic noises from wind turbine blades which is based on traditional acoustic formulas is established. The program to calculate the aerodynamic noises from the 2 MW wind turbine blades is compiled using a time-domain analysis method based on the Simulink modular in Matlab software. And the pressure time sequence diagrams of the aerodynamic noises from wind turbine blades are drawn. It has provided a theoretical foundation to develop low noise wind turbine blades.
2015, 36(2):210-218. DOI: 10.7535/hbkd.2015yx02015
Abstract:Dye-sensitized solar cells (DSSC) attracted widespread attention for its low cost, being easy to manufacture, large-scale production and environmentally friendly features. Sensitizer is a core component of the DSSC which plays a role in collecting sunlight and injecting excited state electron into the conduction band of the semiconductor, which is crucial to the photo-electric conversion efficiency. Organic dyes have a number of advantages such as easy synthesizing and tuning of photo-physical and electrochemical properties through molecular design. Triphenylamine is a strong electron donating group, and its non-planar spatial structure makes the degree of the dye molecules aggregation to be decreased. These properties are conducive to improve the absorption properties of the dye and the electron transport efficiency. In recent years, triphenylamine or substituted triphenylamine as electron donor of organic sensitizers becomes the research focus for improving the photoelectric conversion efficiency of solar cells. In this paper, the progress of triphenylamine photosensitive dyes is described.
2015, 36(2):219-224. DOI: 10.7535/hbkd.2015yx02016
Abstract:The heat storage process of the high temperature thermal energy storage container using single-stage PCM for solar thermal power generation is numerically simulated. The change curves of the PCM’s temperature and liquid rate over time during the single-stage thermal stage melting process and its cloud distributions of the liquid rate at different time have been obtained. Through the analysis of the curves and cloud figures, in the premise of ensuring the heat accumulation amount, three kinds of PCM cascade regenerative high temperature thermal energy storage container design schemes are derived and simulated on their regenerative performance. The result indicates that the cascade heat storage schemes greatly reduce the total heat storage time and the "dead zones" effects effectively on the performance of heat storage during the single-stage regenerative terminal stage, which can make the PCM liquid rate distribution to be more uniform. It provides the theoretical basis for the optimization design of the high temperature phase change thermal energy storage container for solar thermal power generation applications.