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Preparation and Unimolecular-Micellization Behavior of Homopolymer of Surface-Active Monomer AMC14AB

Chinese Journal of Chemical Physics 2008年第5期21卷 469-475页

作者： Kang-kai Liu Lei Li Institute of Coal Chemistry Chinese Academy of Sciences Taiyuan 030001 China Economy and Commerce Committee of Shanxi Province Taiyuan 030001 China

（2-acrylamido） ethyl tetradecyl dimethylammonium bromide （AMC14AB） was polymerized in aqueous solu- tion to form the homopolymer P（AMC14AB）. The physicochemical properties of P（AMC14AB） in aqueous solution were mainly studied with fluorescent probe method, surface tension measurement and conductom- etry. The experimental results show that the aggregation morphology of P（AMC14AB） in aqueous solution is unimolecular micelle as expected. Being different from conventional multimolecular micelle systems, the unimolecular micelle system of P（AMC14AB） not only shows critical micellar concentration （CMC=0）, （i.e. once added to pure water, the surface tension decreases immediately in spite how small the density is）, but also the surface tension stays almost the same with the concentration increasing. That is to say, there is no mutational point on the relationship curve between surface tension and concentration. Furthermore, the unimolecular micelle system of P（AMC14AB） has no Krafft temperature, i.e. at any temperature, so long as it is dissolved in water, the unimolecular micelles will form. Besides this, for the solubilization of hydrophobic organic substances, the unimolecular micelle system of P（AMC14AB） is obviously different from the common multimolecular micelle system, having no turning point on the relationship curve between toluene solubi- lizaion amount and P（AMC14AB） concentration, and the solubilizing ability of the unimolecular-micelle system of P（AMC14AB） for hydrophobic organic substances is much higher than that of the conventional multimolecular micelle solutions of common surfactants, such as centyl trimethyl ammonium bromide.

关键词： Surface active monomer Unimolecular micelle Zero critical micellar concentration Krafft temperature

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Semisolid forging electronic packaging shell with silicon carbon-reinforced copper composites

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Rare Metals 2013年第2期32卷 191-195页

作者： kai-Kun Wang School of Materials Science and Engineering University of Science and Technology Beijing

To fabricate electronic packaging shell of coppermatrix composite with characteristics of high ther mal conductivity and low thermal expansion coefficient, semisolid forming technology, and powder metallurgy was combined. Conventional mechanical mixing of Cu and SiC could have insufficient wettability, and a new method of semisolid processing was introduced for billets preparation. The SiC/Cu composites were first prepared by PM, and then, semisolid reheating was performed for the successive semisolid forging. Composite billets with SiC 35 % vol ume fraction were compacted and sintered pressurelessly, microstructure analysis showed that the composites pre pared by PM had high density, and the combination between SiC particles and Cualloy was good. Semisolid reheating was the crucial factor in determining the micro structure and thixotropic property of the billet. An opti mised reheating strategy was proposed： temperature 1,025 ℃and holding time 5 min.

关键词： Semi-solid forming Silicon carbon reinforcedcopper composites Electronic packaging shell Microstructure

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Thixo-forging and simulation of complex parts of aluminum alloy AlSi7Mg

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International Journal of Minerals,Metallurgy and Materials 2010年第1期17卷 53-57页

作者： kai-kun Wang School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China

In order to investigate the formability of metal material in semisolid state, a series of experiments were carried out by thixo-forging the complex part of aluminum alloy AlSi7Mg. Through changing the upper punch, aluminum parts with different upper-cup dimensions can be successfully produced. The numerical simulation was conducted for investigating the forming limits of AlSi7Mg during thixo-forging. It is found that the simulation result is in good agreement with the experiment one.

关键词： thixo forging aluminum alloy formability numerical simulation

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New Wronskian Form of the N-Soliton Solution to a (2+1)-Dimensional Breaking Soliton Equation

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Chinese Physics Letters 2012年第6期29卷 72-74页

作者： CUI kai School of Economics and Management North China University of Water Conservancy and Electric PowerZhengzhou 450046

Soliton phenomena exist in nonlinear science and the financial *** using the Wronskian technique,a new Wronskian condition is proposed for a (2+1)-dimensional breaking soliton ***,with the help of the bilinear transformation,a new Wronskian form of the N-soliton solution is obtained for the (2+1)-dimensional breaking soliton equation.

关键词： equation field soliton

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Estimating Subdivision Depth of Catmull-Clark Surfaces

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Journal of Computer Science & Technology 2004年第5期19卷 657-664页

作者： Hua-WeiWang kai-HuaiQin DepartmentofComputerScienceandTechnology TsinghuaUniversityBeijing100083P.R.China

In this paper, both general and exponential bounds of the distance between a uniform Catmull-Clark surface and its control polyhedron are derived. The exponential bound is independent of the process of subdivision and can be evaluated without recursive subdivision. Based on the exponential bound, we can predict the depth of subdivision within a user-specified error tolerance. This is quite useful and important for pre-computing the subdivision depth of subdivision surfaces in many engineering applications such as surface/surface intersection, mesh generation, numerical control machining and surface rendering.

关键词： Catmull-Clark surface subdivision depth control polyhedron approximation error

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Evolvable dialogue state tracking for statistical dialogue management

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Frontiers of Computer Science 2016年第2期10卷 201-215页

作者： kai YU Lu CHEN kai SUN Qizhe XIE Su ZHU Key Laboratory of Shanghai Education Commission for Intelligent Interaction and Cognitive EngineeringSpeechLab Department of Computer Science and Engineering Shanghai Jiao Tong University Shanghai 200240 China Department of Computer Science Cornell University Ithaca NY 14853 USA

Statistical dialogue management is the core of cognitive spoken dialogue systems （SDS） and has attracted great research interest. In recent years, SDS with the ability of evolution is of particular interest and becomes the cuttingedge of SDS research. Dialogue state tracking （DST） is a process to estimate the distribution of the dialogue states at each dialogue turn, given the previous interaction history. It plays an important role in statistical dialogue management. To provide a common testbed for advancing the research of DST, international DST challenges （DSTC） have been organised and well-attended by major SDS groups in the world. This paper reviews recent progresses on rule-based and statistical approaches during the challenges. In particular, this paper is focused on evolvable DST approaches for dialogue domain extension. The two primary aspects for evolution, semantic parsing and tracker, are discussed. Semantic enhancement and a DST framework which bridges rule-based and statistical models are introduced in detail. By effectively incorporating prior knowledge of dialogue state transition and the ability of being data-driven, the new framework supports reliable domain extension with little data and can continuously improve with more data available. This makes it excellent candidate for DST evolution. Experiments show that the evolvable DST approaches can achieve the state-of-the-art performance and outperform all previously submitted trackers in the third DSTC.

关键词： dialogue management domain extension,evolvable dialogue state tracking parser tracker

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Optimization of SVC settings to improve post-fault voltage recovery and angular stability

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Journal of Modern Power Systems and Clean Energy 2019年第3期7卷 491-499页

作者： Weihong HUANG kai SUN The Department of Electrical Engineering and Computer Science The University of Tennessee

In this paper, controller parameters of static var compensators(SVCs) at planned locations are optimized to mitigate fault-induced delayed voltage recovery issues and improve angular stability of a multi-machine power system. The problem is formulated as a nonlinear optimization problem involving constraints on post-fault trajectories of voltages and frequencies. This paper proposes a mesh adaptive direct search based algorithm interfaced with a power system simulator for the optimization of SVC controllerparameters. The proposed method is tested on an NPCC140-bus system to optimize controller parameters for three SVCs. Simulations on critical contingencies verify that post-fault transient voltages and generator speeds can both quickly recover and transient stability of the system is improved.

关键词： Static var compensator (SVC) Fault-induced delayed voltage recover issue(FIDVR) Angular stability Mesh adaptive direct search(MADS) algorithm

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Concise review of relaxations and approximation algorithms for nonidentical parallel-machine scheduling to minimize total weighted completion times

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Journal of Systems Engineering and Electronics 2008年第4期19卷 827-834页

作者： Li kai Yang Shanlin School of Management Hefei Univ. of Technology Hefei 230009 P. R. China

A class of nonidentical parallel machine scheduling problems are considered in which the goal is to minimize the total weighted completion time. Models and relaxations are collected. Most of these problems are NP-hard, in the strong sense, or open problems, therefore approximation algorithms are studied. The review reveals that there exist some potential areas worthy of further research.

关键词： parallel machine scheduling review total weighted completion time relaxation algorithm

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Drag Effects of Solute and Second Phase Distributions on the Grain Growth Kinetics of Pre-Extruded Mg-6Zn Alloy

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Journal of Materials Science & Technology 2016年第12期32卷 1260-1266页

作者： Zhaoyang Jin Donghua Yu Xintong Wu kai Yin kai Yan College of Mechanical Engineering Yangzhou University

In order to control the grain size during hot forming,grain growth behavior of a pre-extruded Mg-6Zn magnesium alloy and its correlation with solute and second phase distribution were *** annealing was conducted on a Gleeble-1500 thermo-mechanical *** mean grain size Dg of each annealed specimen was measured by the quantitative metallography *** grain growth kinetics of the Mg-6Zn alloy annealed at 473-623 K was obtained as Dg^4- Dg0^4=2.25 ×10^11 exp（-95450）by the least square linear regression *** deviation of grain growth exponent n = 4 from the theoretical value of 2 may be attributed to the presence of solute zinc and second phases which will retard the boundary *** observations show that the non-uniform distribution of grain size for samples pre-extruded or annealed at low temperatures is closely related to the non-uniform distribution of fine and dispersed second phases but not to the non-uniform distribution of solute *** indicates that second phase pinning effect plays an important role in microstructure refinement.

关键词： Grain growth kinetics Second phase distribution Solute dragging Magnesium alloys

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Fuzzy Clustering with the Structural α-Entropy

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Chinese Journal of Electronics 2018年第6期27卷 1118-1125页

作者： LI kai GAO Yan School of Cyber Security and Computer Hebei University

We study fuzzy clustering with the structural α-entropy and present a unified framework for fuzzy clustering with fuzzy entropy, which can be regarded fuzzy clustering with fuzzy entropy as its special case. Then,aiming at weighting exponent m equal to the structuralα-entropy index α in the presented unified framework, we obtain the fuzzy membership degrees and cluster centers using Lagrange method. Further, we propose the Structural α-entropy based fuzzy c-means(SEFCM) ***, to solve clustering of the complicated data, we also present the Structural α-entropy based kernel fuzzy c-means(SEKFCM) algorithm. In experiment, some University of California Irvine(UCI) data sets and synthetic data sets are used to test the performance of the presented algorithms and the role of the structural α-entropy. The experimental results show that the presented algorithms obtain better clustering result.

关键词： Structural α-entropy Unified framework Kernel function Fuzzy clustering Structural α-entropy based fuzzy c-means(SEFCM) algorithm Structural α-entropy based kernel fuzzy c-means(SEKFCM) algorithm

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