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1.
《世界制造技术与装备市场》2003,(5)
1. China's Economic Development and Metal Working Machine Tool Market In 2003, the Chinese government is constantly implementing the policy of expanding domestic demands, practicing active financial policies and stabilizing monetary policies. In the meantime the government has issued RMB 140 billion yuan long-term state treasury bonds to enlarge the scale of investment in fixed assets. Despite the economic growth is slow-down and lack of power to speed the economic growth up in the globe as well as impacted by SRAS 相似文献
2.
James K.Mills 《机械工程学报(英文版)》2004,17(2):166-169
The transformation process of an m-DOF free-floating robot from one static state to a dif-ferent static state has m degrees of freedom. The proposed approach of these transformations utilizes aseries of single-DOF transformation processes as an altomative to the m-DOF transformation process.TWO static state transformation processes are studied in detail. First, a single-DOF transformation pro-cess is established using a newly defined concept, referred to as transformation planning, and the defi-nite integral of conservation of angular momentum. Second, the governing equation of the single-DOFtransformation process is established using the dynamic equations of motion of the robot. This allowsthe joint torques to be computed to effect the state transformation. Finally,an extension of the sin-gle-DOF transformation process is proposed to extend the application of uns proposed transformationmethodology to create a transformation net which allows the reconfiguration of a robot from one stateto many other pos 相似文献
3.
《世界制造技术与装备市场》2009,(3)
China's State Council recently passed in principle the auto industry rejuvenation plan.
Major contents of the plan are:to foster auto consum ption market, including a 50 percent cut in the vehicle purchase tax on passenger vehicles with a displacement of 1.6 liters and below; to promote reorganization of the auto industry and support large auto enterprise groups to carry out mergers and acquisitions, and key auto spare enterprises to expand production; to support independent innovation and technical upgrading by enterprises: the central government wiU appropriate RMB 10 billion in a special fund to support technical innovation and renovation and development of new energy automobiles and spare parts by enterprises in the next three years;to implement a new energy auto strategy :subsidy from the central budget will be appropriated to support the spread of energy saving and new energy automobiles in large-and medium-sized cities; and to promote development of independent brands of automobiles, speed up construction of auto and spare parts exportbases, develop a modern auto service industry and improve auto credit. 相似文献
4.
《世界制造技术与装备市场》2008,(6)
China and the United States have made substantial progress in financial cooperation and openness in the Fourth Sino-US Strategic Economic Dialogue, with China promising to let qualified overseas companies get listed on the Chinese stock market,fix the lockup period for QFII investment principal at three months,and to allow qualified foreign banks of legal entity to issue RMB subordinated bonds. The two will further study possibilities of cooperation in insurance. 相似文献
5.
The high working junction temperature of power component is the most common reason of its failure. So the thermal design is of vital importance in electronic control unit (ECU) design. By means of circuit simulation, the thermal design of ECU for electronic unit pump (EUP) fuel system is applied. The power dissipation model of each power component in the ECU is created and simulated. According to the analyses of simulation results, the factors which affect the power dissipation of components are analyzed. Then the ways for reducing the power dissipation of power components are carried out. The power dissipation of power components at different engine state is calculated and analyzed. The maximal power dissipation of each power component in all possible engine state is also carried out based on these simulations. A cooling system is designed based on these studies. The tests show that the maximum total power dissipation of ECU drops from 43.2 W to 33.84 W after these simulations and optimizations. These applications of simulations in thermal design of ECU can greatly increase the quality of the design, save the design cost and shorten design time 相似文献
6.
Quality control on crimping of large diameter welding pipe 总被引:1,自引:1,他引:0
Crimping is used in production of large diameter submerged-arc welding pipes. Many researches are focused on crimping in certain manufacturing mode of welding pipe. The application scopes of research achievements become limited due to lack of uniformity in theoretical analysis. In order to propose a crimping prediction method in order to control forming quality, the theory model of crimping based on elastic-plastic mechanics is established. The main technical parameters are determined by theoretical analysis, including length of crimping, base radius of punch, terminal angle of punch, base radius of die, terminal angle of die and horizontal distance between punch and die. In addition, a method used to evaluate the forming quality is presented, which investigates the bending angle after springback, forming force, straight edge length and equivalent radius of curvature. In order to investigate the effects of technical parameters on forming quality, a two-dimensional finite element model is established by finite element software ABAQUS. The finite element model is verified in that its shapes error is less than 5% by comparable experiments, which shows that their geometric precision meets demand. The crimping characteristics is obtained, such as the distribution of stress and strain and the changes of forming force, and the relation curves of technical parameters on forming quality are given by simulation analysis. The sensitivity analysis indicates that the effects of length of crimping, technical parameters of punch on forming quality are significant. In particular, the data from simulation analysis are regressed by response surface method (RSM) to establish prediction model. The feasible technical parameters are obtained from the prediction model. This method presented provides a new thought used to design technical parameters of crimping forming and makes a basis for improving crimping forming quality. 相似文献
7.
Jang-myung LEE 《测试科学与仪器》2011,(3):288-292
In this paper,we present a method for localization of a rail autonomous pesticide spraying and sampling robot working in greenhouse using an absolute localization system.Design and implementation of the localization system comes from the usage of beacon systems each of which is composed of an RF single receiver and an ultrasonic transmitter.The RF single receiver gets the synchronization signal from the mobile robot,and the ultrasonic transmitter sends ultrasonic signal,thus the distance from the beacon to the ultrasonic receiver can be measured.The position of a beacon in coordinate system of robot can be calculated according to distance information from the beacons to two ultrasonic receivers which are mounted on the robot.Based on the coordinate transformation,the position of a mobile robot can be calculated from the beacon’s absolute position information in the global coordinate system.Experiments demonstrate the effectiveness of the proposed method in real world applications. 相似文献
8.
《世界制造技术与装备市场》2006,(6):64-65
Yunnan Province in Southwest China has published the Rules on Promotion of Foreign Investment,which became effective on June 1. According to the rules,with the exception of sectors and projects which are banned from investment by laws and regulations of the state and the province,foreign investors are allowed to make investment within the province. Investors from overseas are encouraged to invest in the following six sectors:1. supporting facilities for tobacco production,minerals,elect… 相似文献
9.
Distortion is a technical indicator in the field of common voice signal processing.The design is a portable distortion degree tester,based on Field-Programmable Gate Array(FPGA,EP2C20)as the core,using harmonic analysis method which better solve the distortion problem of accuracy.It can achieve the signal transformation from the time-domain to the frequency-domain,and is widely used for signal spectrum analysis.All the components used in the design are low power,high performance,low drift and industrial grade components.The reference voltage sources of ADC and DAC have identical performance of high stability,high precision.The clock is the precise stable clock with FPGA temperature compensation.This project can get the cost-effective,high-precision,low power and portable design goals. 相似文献
10.
Bi Kexin Ding Xiaohui Zhang TiezhuCollege of Economic Management Harbin University of Scienceand Technology Harbin ChinaFeng YingjunCollege of Management Harbin Institute of Technology Harbin China 《机械工程学报(英文版)》2004,17(1):40-45
Measure index system of technical innovation in medium and small manufacturing enterprises is established according to principles of exploration, adaptability, standardization, generalization, feasibility, comparability and combination of economic benefit and continual development. It includes index of technical innovation capacity, informational administration on technical innovation, and investment of technical innovation, economic benefit, green technical level, social contribution and other influential indexes. Approach to measure of technical innovation in medium and small manufacturing enterprises is presented based on combination of grey relation and fuzzy hiberarchy analysis, and conclusions are drawn based on practical analysis of 20 medium and small enterprises, which provides the basis for the medium and small enterprises to select technical innovation policies and the government to constitute relative policies. 相似文献
11.
LI Xiaoquan DU Zeyu School of Materials Science Engineering Tianjin University Tianjin China YANG Xuguang School of Materials Science Engineering Jiangsu University of Science Technology Zhenjiang China 《机械工程学报(英文版)》2007,20(1)
For characteristics of open and far from thermodynamic equilibrium in welding chemical reaction, a new kind of quantitative method, which is used to analyze direction and extent for chemi- cal reaction of SiO_2/Fe during quasi-steady state period, is introduced with the concept of non-equilibrium stationary state. The main idea is based on thermodynamic driving forces, which result in non-zero thermodynamic fluxes and lead to chemical reaction far away from thermodynamic equilibrium. There exists certain dynamic equilibrium relationship between rates of diffusion fluxes in liquid phase of reactants or products and the rate equation of chemical reaction when welding is in quasi-steady state. As result of this, a group of non-linear equations containing concentrations of all substances at interface of slag/liquid-metal may be established. Moreover the stability of this non-equilibrium stationary state is discussed using dissipative structure theory and it is concluded theoretically that this non-equilibrium stationary state for welding chemical reaction is of stability. 相似文献
12.
Approved by the state Department of Commerce, the Association of Rubber Marketing Committee and the Business Technology Center are responsible for organizing more than 20 enterprises, based on the actual conditions of China's tire market, complied with relevant state laws and regulations, focused on upgrading the quality of the services market to achieve in laws, regulations, and technical management whic is an orderly manner under the guidance of the principle of competition, 相似文献
13.
正The emerging and development of Artificial Intelligence(AI), especially deep learning, has stimulated its application in various engineering domains. Monitoring, diagnosis and prognosis, as the key elements of intelligence maintenance of manufacturing systems in the era of Industry 4.0, has also benefited from the advancement of AI technology. e main objective of this special issue aims at bringing scholars to show their research findings in the field of monitoring, diagnosis and prognosis driven by AI, and promote its application in intelligent maintenance of manufacturing system in China. Ten papers have been selected in this special issue after rigorous review and they represent the latest research outcomes in this active area. 相似文献
14.
QIANG Jiaxi AO Guoqiang YANG Lin 《机械工程学报(英文版)》2008,21(3):20-25
A combined algorithm for battery state of charge (SOC) estimation is proposed to solve the critical issue of hybrid electric vehicle (HEV). To obtain a more accurate SOC, both coulomb-accumulation and battery resistance-capacitor (RC) model are weighted combined to compensate the deficiencies of individual methods. In order to solve the key issue of coulomb-accumulation, the battery thermal model is used. Based on the principle of energy conservation, the heat generated from battery charge and discharge process is converted into the equivalent electricity to calculate charge and discharge efficiency under variable current. The extended Kalman filter (EKF) as a closed loop algorithm is applied to estimate the parameters of resistance-capacitor model. The input variables do not increase much computing difficulty. The proposed combined algorithm is implemented by adjusting the weighting factor of coulomb- accumulation and resistance-capacitor model. In the end, four different methods including Ah-efficiency, Ah-Equip, RC-SOC and Combined-SOC are compared in federal testing procedure (FTP) drive cycle. The experiment results show that the proposed method has good robustness and high accuracy which is suitable for HEV application. 相似文献
15.
Liu Jichang Li Lijun Laser Institute Hunan University Changsha China 《机械工程学报(英文版)》2005,18(2):263-266
A low-power CO2 laser is used to deposit Fe powder and mixture of Fe and carbon powder on substrates respectively, and the macro and micro-structure of the formed samples are investigated. It is demonstrated that most grains of these samples are equi-axed. This is derived from the high nucleation velocity in the shallow melt pool besides rapid solidification of the liquid-state alloy or metal. Bainitic structure, combination of pearlite and ferrite structure and ferrite structure are seen respectively in the samples involving various amounts of carbon owing to no martensitic transformation in these small samples. 相似文献
16.
The problem of linear time-varying(LTV) system modal analysis is considered based on time-dependent state space representations, as classical modal analysis of linear time-invariant systems and current LTV system modal analysis under the ‘‘frozen-time' assumption are not able to determine the dynamic stability of LTV systems.Time-dependent state space representations of LTV systems are first introduced, and the corresponding modal analysis theories are subsequently presented via a stabilitypreserving state transformation. The time-varying modes of LTV systems are extended in terms of uniqueness, and are further interpreted to determine the system's stability. An extended modal identification is proposed to estimate the time-varying modes, consisting of the estimation of the state transition matrix via a subspace-based method and the extraction of the time-varying modes by the QR decomposition. The proposed approach is numerically validated by three numerical cases, and is experimentally validated by a coupled moving-mass simply supported beam experimental case. The proposed approach is capable of accurately estimating the time-varying modes, and provides a new way to determine the dynamic stability of LTV systems by using the estimated time-varying modes. 相似文献
17.
《橡塑机械时代》2009,21(5):11-11
Director Huang Jianzhong from Division of comprehensive utilization of resources, Ministry of information industry and energy-saving pointed out at wood and plastic industry about the relevant policies that to establish the wood industry standards to regulate and promote enterprise development as soon as possible. In addition, related preferential policies which are not carried out well for encouraging the development of wood and plastic industry, Huang Jianzhong hopes that the trade association should reflect the implementation of the policy to related department in time and made targeted recommendations about existence questions. 相似文献
18.
A new mathematical method is proposed to convert the oscillator instability parameters from Allan variance to Spectrum Density(SD)of random phase fluctuations,which is the inversion of the classic transformation formula from SD to Allan variance.Due to the fact that Allan variance does not always determine a unique SD function,power-law model of the SD of oscillator phase fluctuations is introduced to the translating algorithm and a constrained maximum likelihood solution is presented.Considering that the inversion is an ill-posed problem,a regularization method is brought forward in the process.Simulation results show that the converted SD of phase fluctuations from Allan variance parameters agrees well with the real SD function.Furthermore,the effects of the selected regularization factors and the input Allan variances are analyzed in detail. 相似文献
19.
LIU Wei YANG Canjun WU Shijun XIE Yingjun CHEN Ying 《机械工程学报(英文版)》2008,21(1):72-76
Sampling study is an effective exploration method, but the most extreme environments of hydrothermal vents pose considerable engineering challenges for sampling hydrothermal fluids. Moreover, traditional sampler systems with sample valves have difficulty in maintaining samples in situ pressure. However, decompression changes have effect on microorganisms sensitive to such stresses. To address the technical difficulty of collecting samples from hydrothermal vents, a new bidirectional high pressure-resistant sample valve with balanced poppet was designed. The sample valve utilizes a soft high performance plastic "PEEK" as poppet. The poppet with inapposite dimension is prone to occur to plastic deformation or rupture for high working pressure in experiments. To address this issue, based on the fmite element model, simulated results on stress distribution of the poppet with different structure parameters and preload spring force were obtained. The static axial deformations on top of the poppet were experimented. The simulated results agree with the experimental results. The new sample valve seals well and it can withstand high working pressure. 相似文献
20.
WANG Huaming ZHU Jianying School of Mechanical Electrical Engineering Nanjing University of Aeronautics Astronautics Nanjing China 《机械工程学报(英文版)》2007,20(1):115-119
A two-stage object recognition algorithm with the presence of occlusion is presented for microassembly. Coarse localization determines whether template is in image or not and approximately where it is, and fine localization gives its accurate position. In coarse localization, local feature, which is invariant to translation, rotation and occlusion, is used to form signatures. By comparing signature of template with that of image, approximate transformation parameter from template to image is obtained, which is used as initial parameter value for fine localization. An objective function, which is a function of transformation parameter, is constructed in fine localization and minimized to realize sub-pixel localization accuracy. The occluded pixels are not taken into account in objective function, so the localization accuracy will not be influenced by the occlusion. 相似文献