检索结果-南通市图书馆

Electrochemical Characteristic of Decarburization Reaction

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 1999年第1期13卷 27-30页

作者： Xionggang Lu Fushen Li Lifen Li Kouchih Chou (Applied science school, university of science and Technology Beijing, Beijing 100083, china)(Material science and Engineering school, Shanghai university, Shanghai 200072, china) Applied science school University of Science and Technology Beijing Beijing 100083 China Material science and Engineering school Shanghai University Shanghai 200072 China

The electrochemical mechanism of the reaction between Fe-C melts and CaO-SiO2-Al2O3-FeOx slag systems has been carried out. The experimental results suggest that the final content of carbon in melt increases as the partial oxygen pressure of gas decreases no matter whether there is electronic conductor or not. However, the final content of carbon in the system with electronic conductor is much lower than that without electronic conductor. It can be deduced that the transfer ability of oxygen in slag is dominated by electrons. When an electronic conductor exists, an easy pathway for the electrons is provided and the oxygen transfer rate is accelerated.

关键词： melt-slag reaction decarburization electrochemistry electronic conductor

Improve Fractal Compression Encoding Speed Using Feature Extraction and Self-organization Network

在线全文

学校读者我要写书评

暂无评论

Journal of university of science and Technology Beijing 2001年第4期8卷 306-310页

作者： Berthe Kya, Yang Yang information Engineering school. university of science and Technology Beijing. Beijing 100083. china Univ Sci & Technol Beijing Informat Engn Sch Beijing 100083 Peoples R China

Image compression consists of two main parts: encoding and decoding. One of the important problems of the fractal theory is the long encoding implementation time, which hindered the acceptance of fractal image compression as a practical method. The long encoding time results from the need to perform a large number of domain-range matches, the total encoding time is the product of the number of matches and the time to perform each match. In order to improve encoding speed, a hybrid method combining features extraction and self-organization network has been provided, which is based on the feature extraction approach the comparison pixels by pixels between the feature of range blocks and domains blocks. The efficiency of the new method was been proved by examples.

关键词： image compression fractal theory features extraction self-organization network fractal encoding

Calculating Model of Mass Action Concentrations for Mn-C Melts and Optimization of Thermodynamic Parameters

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 1998年第4期12卷 208-211页

作者： Jian Zhang(Metallurgy school, university of science and Technology Beijing, Beijing 100083, china) Metallurgy school University of Science and Technology Beijing Beijing 100083 China

Based on the phase diagram, the coexistence theory of the metallic melt structure involving compoundformation and the regularity of melts containing saturated phase, a calculating model of mass action concentrationsfor Mn-C melts was formulated. According to the activities (or activity coefficients AM. and γc.), obtained by theUnified Interaction Parameter Model (UIPM), the thermodynamic parameters G and G at higher temperatures (1628～1873 K) were optimized by the repeated try and error method. It is testified that G G(873～1273 K) and G (298～1623 K), obtained at lower temperatures, can also be used at the above-mentionedhigher temperatures. The calculated N. and N agree well with ac. and ac obtained by UIPM. This result showsthat the deduced model can reflect the structural reality of Mn-C melts.

关键词： Mn-C melts activity coexistence theory mass action concentration

Microstructural Features During Strain Induced Ferrite Transformation in 08 and 20Mn Steels

在线全文

学校读者我要写书评

暂无评论

Journal of university of science and Technology Beijing 2001年第2期8卷 105-110页

作者： Ping Yang, Feng-e Cui, Fuming Wang (Materials science and Engineering school, university of science and Technology Beijing, Beijing 100083, china) (Metallurgy school, university of science and Technology Beijing, Beijing 100083, china) Univ Sci & Technol Beijing Mat Sci & Engn Sch Beijing 100083 Peoples R China Univ Sci & Technol Beijing Met Sch Beijing 100083 Peoples R China

The microstructure evolution during strain induced ferrite transformation was followed in thermal-simulation tests of clean 08 and 20Mn steels. The influences of carbon equivalence and initial austenite grain size on ferrite grain refinement and the volume fraction of ferrite during straining were inspected. The results revealed that the accelerating effect of ferrite transformation by strain was increased as the carbon equivalence decreased. However, finer ferrite grains were obtained at higher carbon content. At strain of similar to1.5 ferrite grains less than 3 mum and 2 mum can be obtained in 08 and 20Mn steels respectively. Whereas the ferrite grain refinement in 08 steel was due to both effects of strain induced transformation and ferrite dynamic recrystallization, that in 20Mn was mainly due to strain induced transformation. Heavy strain can produce fine ferrite grains in coarse austenite grained 08 steel, but it would lead to band microstructure in coarse austenite grained 20Mn.

关键词： clean carbon steel strain induced transformation grain refinement ferrite dynamic recrystallization

A Back Look on the Binary Phase Diagrams of Metals from the Mass Action Law and the Coexistence Theory of Metallic Melts

在线全文

学校读者我要写书评

暂无评论

Journal of university of science and Technology Beijing 2001年第1期8卷 15-19页

作者： Jian Zhang Metallurgy school, university of science and Technology Beijing, Beijing 100083, china Univ Sci & Technol Beijing Met Sch Beijing 100083 Peoples R China

According to the mass action law and the coexistence theory of metallic melts, the mass action concentrations of Cu-Mg, Bi-Tl and Ni-Al melts involving compound formation have been calculated. The calculated results show that, except the ultimate case of pure element, when two elements are present in the melts, all structural units (atoms and molecules) without exception will be present in the melts, i.e., their concentrations may change from great to small, but they will not vanish into nothing, and only under such conditions, the calculated results both agree with practice and obey the law of mass action. In view of that over considerable wide composition range, the activities of both elements of the three solid binary alloys mentioned above have been measured, this seems in contradiction with the present relevant phase diagrams, in which the structural units are determined by composition range, so the latter needs further investigation and consideration.

关键词： activity phase diagram the mass action law the coexistence theory

Calculating Models of Mass Action Concentrations for Ni-Mn and Co-Mn Melts and Optimization of Their Thermodynamic Parameters

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2000年第4期14卷 246-250页

作者： Jian Zhang (Metallurgy school, university of science and Technology Beijing, Beijing 100083, china) Metallurgy school University of Science and Technology Beijing Beijing 100083 China

According to phase diagrams, measured activities as well as the coexistence theory of motallic melts structure involving compound formation, the calculating models of mass action concentrations for Ni-Mn and Co-Mn melts are formulated and their thermodynamic parameters are optimized. As a result, the calculated mass action concentrations agree well with the corresponding measured activities, showing that these models can reflect the structural characteristics of both Ni-Mn and Co-Mn melts.

关键词： activity metallic melts coexistence theory mass action concentration

On the design of compensator for quantization-caused input-output deviation

在线全文

学校读者我要写书评

暂无评论

science china(information sciences) 2011年第4期54卷 824-835页

作者： GUO YuQian,GUI WeiHua & YANG ChunHua school of information science and Engineering,Central South university,Changsha 410083,china 1. school of information science and Engineering Central South University Changsha 410083 China

This paper considers the design of compensators for systems with quantized inputs in order to reduce the influence of *** systems with (vector) relative degrees,we propose a kind of compensators which can compensate for the accumulated output deviation completely caused by *** proposed compensators are capable of keeping the differences of the input-output responses between the systems with quantized inputs and the original systems without considering quantization within certain small *** show that the compensators in this paper are robust with respect to model uncertainties,disturbance and measurement noise and can significantly improve the input-output responses of systems with both input quantization and packet dropouts.

关键词： networked control systems quantization packet dropout I/O deviation compensation

A PRIORITY-BASED POLLING SCHEDULING ALGORITHM FOR ARBITRATION POLICY IN NETWORK ON CHIP

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Electronics(china) 2012年第Z1期 120-127页

作者： Bao Liyong Zhao Dongfeng Zhao Yifan (school of information science and Engineering, yunnan university, kunming 650091, china)

A solution is imperatively expected to meet the efficient contention resolution schemes for managing simultaneous access requests to the communication resources on the Network on Chip (NoC). Based on the ideas of conflict-free transmission, priority-based service, and dynamic self-adaptation to loading, this paper presents a novel scheduling algorithm for Medium Access Control (MAC) in NoC with the researches of the communication structure features of 2D mesh. The algorithm gives priority to guarantee the Quality of Service (QoS) for local input port as well as dynamic adjustment of the performance of the other ports along with input load change. The theoretical model of this algorithm is established with Markov chain and probability generating function. Mathematical analysis is made on the mean queue length and the mean inquiry cyclic time of the system. Simulated experiments are conducted to test the accuracy of the model. It turns out that the findings from theoretical analysis correspond well with those from simulated experiments. Further more, the analytical findings of the system performance demonstrate that the algorithm enables effectively strengthen the fairness and stability of data transmissions in NoC.

关键词： Network on Chip (NoC) Arbitration policies Priority-based polling Dynamic load adaptation

LEAST-SQUARES MIXED FINITE ELEMENT METHODS FOR NONLINEAR PARABOLIC PROBLEMS

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2002年第2期20卷 153-164页

作者： Dan-ping Yang (school of Mathematics and System science, Shandong university, Jinan 250100, china) school of Mathematics and System science Shandong University Jinan 250100

Focuses on the formulation of a number of least-squares mixed finite element schemes to solve the initial boundary value problem of a nonlinear parabolic partial differential equation. Convergence analysis; Informatio... 详细信息

关键词： least-squares algorithm mixed finite element nonlinear parabolic problems convergence analysis