• Volume 36,Issue 1,2015 Table of Contents
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    • >Special Column: National Young Scholar/Local Science Foundation
    • Development and application of resilient wheels in urban rail transit vehicle

      2015, 36(1):1-8. DOI: 10.7535/hbkd.2015yx01001

      Abstract (6088) HTML (0) PDF 23.92 M (6498) Comment (0) Favorites

      Abstract:Urban rail transit vehicles have been more and more attractive to people as a kind of fast, comfortable, energy-saving, environmental protection and safe transportation. But because of the vehicle noise and vibration, urban rail vehicles also face severe challenges. The research of resilient wheels has been continuously developed and improved. Based on the review of development background and structure sorts of resilient wheels, the advantages of resilient wheels are described, and the research status of noise and vibration reducing, infinite element strength analysis, vehicle dynamic analysis and the wheel-rail wear of resilient wheels are discussed. Taking the low-floor LRVs (light rail vehicles) in domestic and overseas as example, the development and application of the resilient wheels in city rail transit is described, and the application prospects of the resilient wheels in LRVs in domestic and the future research direction of elastic wheel are discussed.

    • Catastrophe theory and its application status in mechanical engineering

      2015, 36(1):9-15. DOI: 10.7535/hbkd.2015yx01002

      Abstract (2196) HTML (0) PDF 17.53 M (2931) Comment (0) Favorites

      Abstract:Catastrophe theory is a kind of mathematical method which aims to apply and interpret the discontinuous phenomenon. Since its emergence, it has been widely used to explain a variety of emergent phenomena in the fields of natural science, social science, management science and some other science and technology fields. Firstly, this paper introduces the theory of catastrophe in several aspects, such as its generation, radical principle, basic characteristics and development. Secondly, it summarizes the main applications of catastrophe theory in the field of mechanical engineering, focusing on the research progress of catastrophe theory in revealing catastrophe of rotor vibration state, analyzing friction and wear failure, predicting metal fracture, and so on. Finally, it advises that later development of catastrophe theory should pay more attention to the combination of itself with other traditional nonlinear theories and methods. This paper provides a beneficial reference to guide the application of catastrophe theory in mechanical engineering and related fields for later research.

    • Research overview of design method of super light multi-hole class-honeycomb sandwich structure materials

      2015, 36(1):16-22. DOI: 10.7535/hbkd.2015yx01005

      Abstract (2426) HTML (0) PDF 20.57 M (2747) Comment (0) Favorites

      Abstract:With the sandwich structure materials' application and promotion in the field of engineering continuously, existing sandwich structure material gradually cannot meet the design requirements. It is very urgent to develop new sandwich structure materials of high efficiency, energy saving and easy to process. The project puts forward and constructs a new kind of class-honeycomb sandwich structure material combined with important application backgrounds that super light and high strength metal sandwich structure materials are applied into the high weight and high energy consumption equipments of automobile, aerospace and machinery and so on. This research involve: mechanical properties equivalent method for the class-honeycomb sandwich structure and its core; Strength, stiffness and inherent frequency characteristic and failure criterions of the class-honeycomb sandwich structure; based on the failure criterions constructing the multiple-constraint models of the class-honeycomb sandwich structure. The research tries to put forward a new method for innovative design of lightweight material and structure and new ideas of lightweight technology research in theory and practice.

    • >Chemistry and Chemical Industry
    • Preparation of mesoporous Ag/AgBr/TiO2 nanocomposites with comb-type polymer as template

      2015, 36(1):23-29. DOI: 10.7535/hbkd.2015yx01006

      Abstract (2072) HTML (0) PDF 17.78 M (2023) Comment (0) Favorites

      Abstract:The mesoporous TiO2 nanocomposites were fabricated in a water bath at lower temperatures using the sol-gel method with a comb-type polymer as template and tetrabutyl titanate as Ti source. The Ag/AgBr/TiO2 nanocomposites with higher specific surface areas were obtained by the introduction of Ag/AgBr on the surface of the mesoporous TiO2 using a deposition-precipitation method. The as-prepared nanocomposites were characterized by X-ray diffraction (XRD), N2 sorption analysis, transmission electron microscope (TEM) and UV-vis diffuse reflectance spectroscopy (UV-vis DRS). The results showed that both the as-prepared TiO2 and Ag/AgBr/TiO2 exhibited mesoporous structure. The introduction of Ag/AgBr not only decreased the specific surface area of the mesoporous TiO2 from 346 m2/g to 253 m2/g, but also significantly increased its visible light photocatalytic activity. The degradation rate of methyl orange under visible light irradiation over Ag/AgBr/TiO2 was 145 and 60 times of those over the commercial TiO2 P25 and the mesoporous TiO2, respectively.

    • Studies on preparation of aceclofenac pellets by centrifugal granulator

      2015, 36(1):30-35. DOI: 10.7535/hbkd.2015yx01008

      Abstract (2298) HTML (0) PDF 12.05 M (2111) Comment (0) Favorites

      Abstract:To prepare aceclofenac pellets by centrifugal granulation. Using 90~100 g of starch pellets as the core pellets,100 g of aceclofenac mixed with 50 g of microcrystalline cellulose(MCC) and 4 g talc, methyl cellulose (HPMC) as binder,the aceclofenac pellets were prepared by centrifugal granulation .And evaluate the quality of the pellets. The aceclofenac pellets had high yield and less losses,the pellets had a partical size of 0.70~0.88 mm(18~24 mesh)and had uniform particle size .the moisture ,drug content and dissolution meet the requirement . Aceclofenac pellets were prepared by the process of centrifugal granulation .The preparation prescription and process parameters were optimized by single factor method .and the pellets meet the standard requirements.

    • >Mechanical, Electronics and Information Science
    • Combinatorial optimization of order picking and export choosing for bypass type automatic stereoscopic warehouse

      2015, 36(1):36-44. DOI: 10.7535/hbkd.2015yx01009

      Abstract (1948) HTML (0) PDF 21.65 M (1802) Comment (0) Favorites

      Abstract:The automatic stereo warehouse system is a storage system with multi-storey warehouse, by which the automation access and integrated automation management are realized in the computer's direct control and management. The emerging, bypass automatic stereo warehouse has gained more and more application in rapid access. The stacker's working time directly affects the efficiency of the warehouse. To improve the bypass automatic warehouse efficiency and analyze the stacker route, an integrated optimization model considering the export selection and the path picking is established. The model aims to the picking task cycle and develops the population's generating method of genetic algorithm, then solves the optimization model. The last section in this stage is the initial point of the next optimization stage, using the nearest neighbor method to find the optimal export location. Simulation and practical application show that the model and the algorithm are feasible and effective.

    • Diagnosis of inverter switch open circuit faults based on neutral point voltage signal analysis

      2015, 36(1):45-51. DOI: 10.7535/hbkd.2015yx01010

      Abstract (2326) HTML (0) PDF 16.93 M (2119) Comment (0) Favorites

      Abstract:Using the current signal to diagnose inverter faults information is apt to be affected by the load, noise and other factors; besides, it requires long diagnosis period with special algorithms and the diagnosis result is easily to be incorrect with no-load or light-load. Focusing on this issue, the logical analysis method is proposed for correlation logical analysis of leg neutral-point voltage and pulse signal to realize the diagnosis of the open circuit faults of inverter switches. The logical expressions of output signals of inverter power tube open-circuit faults is put forward and interrelated hardware circuit design is also elaborated. Delaying the rising edge of inverter power tube's pulse signal can effectively avoid the diagnosis error caused by the power tube's switching on/off. The experiment results show that the method can effectively diagnose the open-circuit faults of single-phase single power tube inverter in real-time and the hardware circuit cost is low, which shows it is effective and feasible.

    • Study on solitary word based on HMM modeland Baum-Welch algorithm

      2015, 36(1):52-57. DOI: 10.7535/hbkd.2015yx01011

      Abstract (3553) HTML (0) PDF 12.46 M (3261) Comment (0) Favorites

      Abstract:This paper introduces the principle of Hidden Markov Model, which is used to describe the Markov process with unknown parameters, is a probability model to describe the statistical properties of the random process. On this basis, designed a solitary word detection experiment based on HMM model, by optimizing the experimental model, Using Baum-Welch algorithm for training the problem of solving the HMM model, HMM model to estimate the parameters of the λ value is found, in this view of mathematics equivalent to other linear prediction coefficient. This experiment in reducing unnecessary HMM training at the same time, reduced the algorithm complexity. In order to test the effectiveness of the Baum-Welch algorithm, The simulation of experimental data, the results show that the algorithm is effective.

    • Design of bridge crane girder strain acquisition system based on virtual instrument

      2015, 36(1):58-62. DOI: 10.7535/hbkd.2015yx01012

      Abstract (2082) HTML (0) PDF 12.88 M (2436) Comment (0) Favorites

      Abstract:Girder is an important part of the bridge crane, which is also the main force element. In order to prevent accidents, it is necessary to collect the bridge crane girder stress data to analyse the fatigue life. This paper constructs a bridge crane girder strain acquisition system. The hardware system consists of sensors, connectors, data acquisition cards, wireless data transmission groups, POE power and host computer. The software system consists of NI MAX to interface with the computer's NI hardware and software resources,and LabVIEW programming to display and storage the girder strain data. Through this system, positions and working days strain data acquisition for the 50/10 t bridge crane girder gets the key positions strain data. The results show that the girder strain data acquisition system runs stably, channel signals of acquisition task transmit accurately, and the terminal data stores competely, meeting the detection requirements, which provides an important data support for the subsequent fatigue analysis and accurate remaining service life prediction of the crane girder.

    • >Textile Science
    • Research of a novel method for measuring yarn hairiness based on image recognition

      2015, 36(1):63-72. DOI: 10.7535/hbkd.2015yx01013

      Abstract (2376) HTML (0) PDF 22.65 M (1842) Comment (0) Favorites

      Abstract:Aiming at hairiness measurement, a digital image acquisition system is constructed, based on which a novel algorithm is proposed in order to measure the number and length of yarn hairiness. The algorithm can be used to make feature analysis of yarn images captured continuously, and yarn hairiness features for quality evaluation of yarn hairiness are determined. With pretreatment of yarn image, including gray-scale transformation, background subtraction, image enhancement, dynamic threshold segmentation, tilt correction, image denoising and image segmentation, yarn hairiness image is obtained. Then the yarn hairiness image is treated by using thinning algorithm, so the thinned yarn hairiness image is obtained. With yarn axis and the margin of trunk as reference, and with proper baseline, yarn hairiness image skeleton is extracted at the pixel level, and the number of yarn hairiness of different length is determined by statistics. Experimental results show that the precision of the new method is consistent with the visual observation method, and its deviation is within 5%. The method can improve the efficiency and accuracy of yarn hairiness feature extraction.

    • Research on tensile fracture process of ring-spun yarn based on AE technique and HHT

      2015, 36(1):73-79. DOI: 10.7535/hbkd.2015yx01014

      Abstract (2309) HTML (0) PDF 18.19 M (2211) Comment (0) Favorites

      Abstract:The audio signals of polyester filament and ring-spun yarn were collected respectively during tensile failure by self-built Acoustic Emission detection system (AE for short), which is based on the conventional yarn tensile strength tester. And then the Hilbert Huang transform (HHT) program was compiled by Matlab software to analysis and process the collected signals, in order to get the time-frequency characteristics of each damage source in the yarn tensile fracture process. The results show that, AE signal via HHT can be identified two modes involved in polyester ring-spun yarn tensile fracture process, which are fiber fracture and fiber slippage. And the characteristic frequencies of the modes are 30, 20 kHz and 6, 3 kHz respectively. Thus, this paper provides an effective new approach for the analysis and further research of yarn tensile fracture mechanism.

    • >约稿:数据分析与计算专栏
    • Extension of continuity of maps between axiomatic locally finite spaces

      2015, 36(1):81-89. DOI: 10.7535/hbkd.2015yx01017

      Abstract (2201) HTML (0) PDF 20.82 M (1793) Comment (0) Favorites

      Abstract:The paper studies the extension problem of continuous maps between axiomatic locally finite spaces (for short, ALF spaces). Indeed, an ALF space is a topological space satisfying a set of axioms suggested in . Further, an ALF space is defined by using a special kind of neighborhood different from the topological neighborhood in classical topology so that the continuity of maps between ALF spaces can be defined by preserving the neighborhood relation (see Definition 10). Therefore, it is necessary to develop the notions of continuity, homeomorphism and local homeomorphism for such spaces by using the neighborhood relation, which can be applicable in computer science. In the study of a deformation of an ALF space, we can develop a special kind of retract on ALF spaces. By using the retract, we can efficiently deal with the extension of continuous maps between ALF spaces.

    • Permeability evolution model and numerical analysis of coupled coal deformation, failure and liquid nitrogen cooling

      2015, 36(1):90-99. DOI: 10.7535/hbkd.2015yx01016

      Abstract (5691) HTML (0) PDF 23.31 M (12277) Comment (0) Favorites

      Abstract:How to quantitatively evaluate the permeability change of coalbed subjected to liquid nitrogen cooling is a key issue of enhanced-permeability technology of coalbed. To analyze the evolution process of permeability of coupled coal deformation, failure and liquid introgen cooling, the coal is supposed as elastic, brittle and plastic material. Its deformation process includes elastic deformation stage, brittle strength degradation stage and residual plastic flow stage. Combined with strength degradation index, dilatancy index of the element and Mohr-Column strength criterion, the element scale constitutive model with the effects of confining pressure on peak-post mechanical behaviors is built. Based on the deformation process of coal rock, there exist two stages of permeability evolution of the element including decrease of permeability due to elastic contraction and increase due to coal rock element's failure. The relationships between the permeability and elastic deformation, shear failure and tension failure for coal are studied. The permeability will be influenced by the change of pore space due to elastic contraction or tension of element. Conjugate shear zones appear during the shear failure of the element, in which the flow follows so-called cubic law between smooth parallel plates. The calculation formulas of the permeability and the aperture of the fractures are given out based on the volumetric strain. When tension failure criterion is satisfied with the rock element fails and two orthogonal fractures appear. The calculation formulas of the permeability and the width of the fractures are given out based on the volumetric strain. Further, combined with the thermal conduction theory the permeability evolution model of coupled coal deformation, failure and liquid nitrogen cooling is presented. Then Fish function method in FLAC is employed to perform the model. The permeability's evolution process for coal bed cryogenically stimulated by flowing liquid nitrogen through gas production well in Wangyingzi mine, Liaoning province, is simulated and the results include: 1) When liquid nitrogen(LN2) is injected into a rock at warm reservoir temperature, heat from the rock will quickly transfer to the liquid nitrogen resulting in rapid cooling and contraction of coal bed. The nearer the position is to bore hole, the bigger the shrinkage deformation and thermal stress and coal fail when tension stress sufficiently built up. In this paper the tension failure band after 10 days' LN2 cooling is 0.65 m. 2) In tension failure area the cracks from cooling stimulation lead to the significant growth of permeability. The maximum permeability for element is 1.97×105 times more than that before cooling. 3) Apart from the bore hole, the thermal tensile stress leads to the growth of permeability at a rate of 1%~14%, far less than that in the tension failure area. 4) With increasing time the failure area gradually slowly grows up. It indicates that the longer cooling time does not mean better effects. 5) The cooling fracturing area is found to have a 1.0 m band. In practical engineering the pressure in hole bore and phase transition of water also influences the deformation and failure of coal, which leads to much more failure zone of cooling. 6) The evolution process of permeability of coupled coal deformation, failure and liquid introgen cooling can be better reflected by the model in this paper. This study is hoped to provide a simple but reasonable description of the permeability evolution of rocks subject to liquid nitrogen cooling.

    • Research overview of microblog analysis

      2015, 36(1):100-110. DOI: 10.7535/hbkd.2015yx01015

      Abstract (3040) HTML (0) PDF 28.45 M (2415) Comment (0) Favorites

      Abstract:Microblog is one of the important social information communication platform. Because of its characteristics of easy operation and fast spread, people can directly and quickly express their attitude to emergencies, public figures, hot products and daily life through microblog. In order to utilize the vast microblog information, it needs to combine various microblog analysis methods to discover the potential value of information. This paper first reviews the current research of microblog analysis field and puts forward the independent research and development system of microblog analysis, then explores the future research direction of microblog analysis.First of all, this paper introduces two dominating technical methods of microblog analysis, including microblog open platform and web crawler technology. People can have convenient and prompt access to microblog information resources via open interface of microblog, such as microblog content, user reviews, user personal details, the number of fans, the number of attention, etc.. But it also has many limitations. For example, it can only be grabbed for limited times every hour and it is not open for all the resources information. Utilizing the web crawler technology, more information resources can be obtained. For example, the information acquisition technology based on general web crawler can cover a wider range and based on the focused crawler, the predefined theme can be crawled selectively.Secondly, this paper presents the hot issues of current microblog, including analysis on users' behavior and microblog content. Research on microblog user behavior includes: 1) Research on information communication network. Its purpose is to predict future propagation, which uses Gephi visualization tools to present propagation path under microblog diffusion, propagation range and the key of forwarding nodes, etc.. 2) Research on propagation factors. It reveals the possible causes of information dissemination by analyzing users' behavior. 3) Research on user's influence. Different scholars give different methods of measurement, while accurate evaluation of user's influence should take into account many factors, such as the number of fans, the forwarding number, mentioned numbers, reply, and social relationship, etc.. Analysis of the microblog contents includes: 1) Microblog texts pretreatment, including words segmentation and stop words. 2) Microblog hot topic detection. Its methods include statistical method of word frequency and text clustering methods, which are beneficial to the improved detection effect of hot topics without considering the characteristics of dynamic topic evolution. 3) Sentiment analysis, also known as opinion mining, has always been a hot issue in the research field of microblog. It can use microblog expression image to extract emotional words and combine with the method of constructing the semantic dictionary and machine learning to classify the sentiments of microblog, finally judge sentiment polarity of microblog. It can be used for public opinion monitoring, business forecasting and product selection, etc..Thirdly, we put forward We-Reading, an independent research and development system of microblog analysis, and introduce three main modules including sentiment analysis, geographical distribution and propagation graph expansion. Sentiment analysis module classifies users' comments sentiment based on the method of sentiment lexicon. Regional distribution module extracts the geographical position information of users and does statistical analysis in order to show the spread distribution of microblog nationwide. Propagation graph module uses visual means to represent the microblog broadcast of information diffusion, such as forwarding relations, forwarding layer, and forwarding scope, etc..Finally, this paper summarizes the challenging problems that microblog faces from two aspects of technology and applications. Technical analysis of microblog can break interface resource constraints, and improve the efficiency and precision of microblog analysis system. Practical analysis of microblog expands event monitoring, management application and commercial application.

Editor in chief:朱立光


International standard number:ISSN 1008-1542

Unified domestic issue:CN 13-1225/TS

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