Editor in chief：朱立光
International standard number：ISSN 1008-1542
Unified domestic issue：CN 13-1225/TS
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2013, 34(2):91-96. DOI: 10.7535/hbkd.2013yx02008
Abstract:With the urgent needs of high strength, lightweight Al Li alloy structure in weapons industry and aerospace areas, reliable and efficient connection of Al Li alloy appears increasingly important. It is prone to porosity, thermal cracks and other defects in traditional Al Li alloy welding methods because of oversized heat input and poor welding stability. In response to these issues, this paper proposed a novel technique using alternating current CMT and DC DC high frequency pulsed composite arc on Al Li alloy welding. In order to get good bonding properties, the low heat input of alternating current CMT arc is used to break oxidation film in alloy surface, reduce porosity and the thermal crack sensitivity of weld pool. The high frequency effect of high frequency pulse arc and its arc ultrasonic is used to refine grains and improve joint strength.
2013, 34(2):97-101. DOI: 10.7535/hbkd.2013yx02005
Abstract:Accumulation of dust can substantially decrease efficiency and even damage solar cells. Previous research suggests that one feasible method of dust removal is high voltage wave electric curtain, which is also confirmed by our work. This project aims to investigate the movement pattern of dust particles under traveling wave electric curtain condition and subsequent optimization of the parameters of wave electric curtain. Firstly, the property of earth dust particles is studied, including particle size distribution, charges, ionization and polarization, and especially the electronic characteristics which are the basis to study the movement rule of dust particles. Secondly, distinct element method and boundary element method are employed to build the moving model of dust particles, charged or uncharged, under the forces of electrostatic, dielectric electrophoresis, resistance and charges. As a result, the movement pattern of the dust particles in the earth's atmosphere environment and corresponding removal mechanism are revealed. Furthermore, numerical simulation and orthogonal experiment are conducted to investigate the relationship between the dust removal efficiency and the parameters of electric curtain, including electrical power parameters (waveform, voltage and frequency), mechanical parameters (electrode width, gap, thin film thickness) and etc. The mathematical model of the dust removal efficiency and the optimization method for electric curtain design are established by using multivariate function optimization methods. The research may provide theoretical basis for the development of self clean techniques for large solar cells and other photoelectric instrument systems under the weather of western China.
2013, 34(2):102-107. DOI: 10.7535/hbkd.2013yx02013
Abstract:Global manufacturing is speeding up to the servicisation, and provides customers with the "physical product plus product service", which is called as integrated service product (ISP). This kind of product has great difference with the traditional mechanical products in modular composition and design. It has scientific significance to study the internal structure relations and macro features of complex integrated service mechanical products, which can optimize product design and improve value added services. This paper analyses ISP and module characteristics, and points out the difference between integrated service product and traditional physical product. Then, it summarizes the progress of the product modular structure modeling methods and the network modeling methods, points out the deficiencies of existing methods applied in integrated service product modeling, and proposes the macro and micro modeling method for integrated service product modeling. Research results show that using complex system theory and complex network theory to integrated service mechanical product modular structure modeling can achieve good effect.
2013, 34(2):108-112. DOI: 10.7535/hbkd.2013yx02010
Abstract:Heavy vehicle has very poor roll stability, causing many tumbling accidents. And the active safety performance, handling and stability performance and side tumbling pre warning technology of heavy vehicle must be improved to reduce the probability of serious traffic accidents and ensure the safety of road transportation. In the paper, the methods of side tumbling pre warning and research status at domestic and abroad are discussed, and problems of present research are pointed out. The hidden Markov theory and the vehicle road collaborative method are also introduced as two key techniques and development trend of side tumbling pre warning method.
2013, 34(2):113-118. DOI: 10.7535/hbkd.2013yx02001
Abstract:A combined method for estimating vehicle side slip angle is published in this paper. Nonlinear factor is introduced to identify the nonlinear degree of vehicle state. A simplified nonlinear side force calculation method is proposed. Then the Kalman filter is designed based on the single track vehicle model associated with the influence of tire cornering stiffness. The evaluation system is constructed based on wheel speed sensor, lateral acceleration and yaw rate sensor, steering angle sensor, MicroAutoBox and GPS system. Slalom and lane change maneuver are conducted on high friction road. The experimental results show that the developed estimation method can reflect the actual state of the vehicle, and the efficiency and accuracy of the proposed method can meet the requirement of the vehicle stability control system.
2013, 34(2):119-124. DOI: 10.7535/hbkd.2013yx02002
Abstract:Based on a preidempotent commutative unital Quantale, quantitative Domain theory is studied by using the approach of fuzzy sets. Fuzzy Scott topology is defined on fuzzy DCPOs, the filter theoretical Scott converngence theory is established and the cartesian closedness of the category of fuzzy DCPOs is proved. Although the obtained results are similar to those in the existing literatures, the proofs are very different from them. These results also indiacte that a preidempotent commutative unital Quantale is the most general lattice in studying quantitative Domain theory by fuzzy set approach.
2013, 34(2):125-127. DOI: 10.7535/hbkd.2013yx02004
Abstract:In this paper, the center of the generalized Liénard systems is discussed, and two main theorems are presented. The results in this paper extend the decidability range of local center in generalized Liénard systems.
2013, 34(2):128-133. DOI: 10.7535/hbkd.2013yx02012
Abstract:This paper presents a 2 D spectrum estimation method based on array signal and the MUSIC algorithm is used in the uniformity linear array 2 D spectrum estimation, realizing the joint estimation between the goal signal frequency and the angle. As the traditional MUSIC algorithm's invalidation, the modified MUSIC method is then applied to the 2 D array signal processing by virtual smoothly, to fulfill joint parameters estimation of coherent signal sources. Simulation results show the validity of the proposed method.
2013, 34(2):134-141. DOI: 10.7535/hbkd.2013yx02006
Abstract:Inspection information in intelligent coordinate measurement contains tolerance information and geometric information，and the recognization and extraction of the information is the key factor for the integration of computer aided design and coordinate measuring machine. This paper introduces the fundamental principle of intelligent coordinate measurement，and reviews the development of extracting inspection information research work. Based on the current development status of full 3D digital design technology，a model based definition method of recognizing and extracting the inspection information is proposed. Considering our current research subject and the part model built in general 3D design software，the process and result of information recognization and extraction are presented.
2013, 34(2):142-146. DOI: 10.7535/hbkd.2013yx02009
Abstract:Aqueous potassium carbonate has a number of advantages such as low solvent costs and low energy consumption, therefore it has been paying more attention in recent years. But its main disadvantage is the slow absorption rate. The addition of promoters into carbonate solutions can effectively enhance the absorption performance. This work reviews the advances in carbon dioxide absorption with the carbonate based solutions. Rate promoters are classified, and their promotion mechanisms are summarized. Meanwhile, research trends such as development of ionic effective promoters and process integration and intensification based on the precipitation technology are highlighted.
2013, 34(2):147-151. DOI: 10.7535/hbkd.2013yx02011
Abstract:Dimethyl carbonate is directly synthesized by reaction of carbon dioxide and methanol with Ce0.4Zr0.6O2 as catalyst under supercritical conditions. The reaction conditions, such as reaction temperature, reaction pressure and reaction time are optimized through the method of orthogonal test and single factor test. The optimum reaction conditions are as follows: the proportion of Ce0.4Zr0.6O2 and methanol is 1∶50, the reaction temperature is 180 ℃, the reaction pressure is 9.5 MPa and the reaction time is 8 h. Under these optimum conditions, the yield of dimethyl carbonate is 7.48% by GC MS analysis.
2013, 34(2):152-158. DOI: 10.7535/hbkd.2013yx02007
Abstract:Living status of genetically engineered microorganism (GEM) in the activated sludge is the key factor influencing bioaugmented treatment effect. The activated sludge adsorption is very important to its survival. The survival of GEM after inoculated into typical activated sludge is investigated and the effects of activated sludge properties on adsorption of GEM are also explored. The result show that adsorption by sludge flocs is more helpful for GEM survival after inoculation. When sludge concentration increases, adsorption capacity of GEM by activated sludge decreases. As floc size decreases, adsorption capacity of GEM increases. In addition, adsorption capacity of GEM increases with an increase in sludge EPS content. The adsorption capacity of normal activated sludge is higher than that of MBR sludge at the same sludge concentration, indicating that the organic content of activated sludge has more influence than floc size on adsorption of GEM. The adsorption of GEM by both normal activated sludge and MBR sludge could be fitted by Freundlich adsorption equation when the inoculating GEM density varied from 105 CFU/mL to 1014 CFU/mL.
2013, 34(2):159-165. DOI: 10.7535/hbkd.2013yx02014
Abstract:The columnar activated carbon from coal is modified by H2O2, and the specific surface area and oxygen containing functional groups of activated carbon are tested before and after H2O2 modified. The static adsorption capacity of trimethylamine, the dynamic penetration curve, and the desorption activation energy of activated carbon are also studied. Experimental results show that surface oxygen functional groups and specific surface area of activated carbon modified with oxidation are significantly improved, and activated carbon treated with 15% H2O2 for 1.5 h is the best. The trimethylamine adsorption capacity can reach 440.9 mg/g, which is 281.5% greater than before. The dynamic adsorption breakthrough time for trimethylamine increases from 10 min to 35 min, and the desorption activation energy increases from 11.461 kJ/mol to 15.663 kJ/mol, which proves that the adsorption performance of modified activated carbon is enhanced.
2013, 34(2):166-172. DOI: 10.7535/hbkd.2013yx02003
Abstract:The quality criteria is studied using SSD and natural logarithm cumulative probability distributing fitting model based on USEPA ECOTOX database. The results indicate that the criteria maximum concentration (CMC) of BPA is 403 μg/L; the criteria continuous concentration (CCC) of BPA is 80.6 μg/L. In addition, the paper also gives accumulation normal distribution function and probability density function of the WQC for BPA. Finally, the paper provides qualitative analysis of the WQC for BPA. Under the premise, the results show that the WQC of BPA has a certain reference value and its deterministic probability lies between 71.43%~100%.