Primal-dual target-following algorithms for linear programming

In this paper, we propose a method for linear programming with the property that, starting from an initial non-central point, it generates iterates that simultaneously get closer to optimality and closer to centrality. The iterates follow paths that in the limit are tangential to the central path. Together with the convergence analysis, we provide a general framework which enables us to analyze various primal-dual algorithms in the literature in a short and uniform way.This work was completed with the support of a research grant from SHELL. The first author is supported by the Dutch Organization for Scientific Research (NWO), Grant No. 611-304-028. The third author is on leave from the Eötvös University, Budapest, and partially supported by OTKA No. 2116. The fourth author is supported by the Swiss National Foundation for Scientific Research, Grant No. 12-34002.92.     

High-temperature X-ray diffraction study of thermolysis of the double complex salt [Rh(NH3)5Cl][PtCl4]

The formation process of a nanosize powder of the equilibrium solid solution Pt_0.50Rh_0.50 by thermolysis of the double complex salt [Rh(NH₃)₅Cl][PtCl₄] under hydrogen or helium and in vacuo was studied in situ by X-ray diffraction and synchrotron radiation. The reduction temperature of the metals in the cationic and anionic moieties of the starting complex is the main factor responsible for the mechanism of solid solution formation. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1069–1073, July, 2006.     

The two steps thermal decomposition of titanium hydride and two steps foaming of Al alloy

1 Introduction Al alloy foam with closed pores prepared by melt foaming, realizing the lightness, high specific strength and multifunction of structure material, is becoming one of the hotspots[1―11]. In order to meet the demand of high-tech, preparing s…     

Rate constants of elementary steps of the reversible chain reaction of N-phenyl-1,4-benzoquinonemonoimine with 2,5-dichlorohydroquinone

The kinetics of reversible chain reactions in quinoneimine-hydroquinone systems has first been studied for the reaction of N-phenyl-1,4-benzoquinonemonoimine with 2,5-dichloro-hydroquinone used as an example. The dependences of the reaction rate on the concentration of the initial reactants, initiator, and each product were studied. The reliable estimates of the rate constants of 11 (of 12) elementary steps of this reaction were obtained from the experimental data using the earlier derived formulas and the method of equal concentrations developed in the present work. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 849–855, May, 2007.     

约瑟夫森结在射频辐照下的亚谐波台阶仿真研究

利用PSp ice软件,采用电路仿真的方法深入研究了约瑟夫森结在射频辐照下的I-V特性,观察到了亚谐波台阶的存在,得出了台阶高度与射频电流幅度的关系,结果对于约瑟夫森结在电压标准和射频检测等方面的应用有重要的参考价值。     

Monte Carlo simulation on backward steps of single kinesin molecule

Kinesin is a stepping molecular motor travelling along the microtubule. It moves primarily in the plus end direction of the microtubule and occasionally in the minus-end, backward, direction. Recently, the backward steps of kinesin under different loads and temperatures start to attract interests, and the relations among them are revealed. This paper aims to theoretically understand these relations observed in experiments. After introducing a backward pathway into the previous model of the ATPase cycle of kinesin movement, the dependence of the backward movement on the load and the temperature is explored through Monte Carlo simulation. Our results agree well with previous experiments.     

基于高温超导双晶结的约瑟夫森效应观测实验

基于YBa2Cu3O7-δ高温超导双晶结,组建了约瑟夫森效应测试装置.利用此装置观察了直流和交流约瑟夫森效应,并测量了约瑟夫森结的临界电流和夏皮罗台阶.     

Calibration error analysis of electro-optical detection systems

We present detailed analysis of calibration process error for electro-optical detection systems, which can be simplified as the plane rotation around a non-orthogonal axis. By means of octonions it firstly proves that the plane rotation around a non-orthogonal axis can be decomposed into rotations around two perpendicular axes. The rotation is further divided into three steps, and the calibration error is hence discussed and obtained. The simulation and test results indicate that there are large calibration errors in calibration process. The pointing error can be effectively improved after separating error components, which provides a more accurate set data for further comDensation.     

Numerical simulation and application of three-dimensional oil resources migration-accumulation of fluid dynamics in porous media

Numerical simulation of oil migration and accumulation is to describe the history of oil migration and accumulation in basin evolution. It is of great value in evaluation of oil resources and determination of the location and amount of oil deposits. Based on such actual conditions as the effects of fluid mechanics in porous media and 3-dimensional geology characteristics, a kind of modified method of second order upwind finite difference fractional steps implicit interactive scheme was put forward. As for the actual problem of Dongying hollow, Huimin hollow, Tanhai region and Yangxin hollow in Shengli Petroleum Oil Field, a numerical simulation test was carried out, and the result is basically coincident with the actual conditions. For the model problem, optimal order estimates were derived. Thus the well-known problem on oil resources was solved. Supported by the National Basic Research Program of China (Grant No. 1999032803), the National Program for Tackling Key Problems (Grant No. 20050200069), the National Natural Science Foundation of China (Grant Nos. 10771124 and 10372052), and the Doctorate Foundation of the Ministry of Education of China (Grant No. 20030422047)     

Random walks on lattices with randomly distributed traps I. The average number of steps until trapping

For a random walk on a lattice with a random distribution of traps we derive an asymptotic expansion valid for smallq for the average number of steps until trapping, whereq is the probability that a lattice point is a trap. We study the case of perfect traps (where the walk comes to an end) and the extension obtained by letting the traps be imperfect (i.e., by giving the walker a finite probability to remain free when stepping on a trap). Several classes of random walks of varying dimensionality are considered and special care is taken to show that the expansion derived is exact up to and including the last term calculated. The numerical accuracy of the expansion is discussed.