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THE RATE OF RETURN ON CAPITAL FOR PENSION SYSTEM IN CHINA

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Journal of Systems science and Systems Engineering 2006年第4期15卷 465-473页

作者： Yunyun JIANG Ruoen REN School of Economics and Management Beihang University Beijing 100083 China

The rate of return on capital is a key parameter in pension reform policy making. While evaluating pension reform, the method Feldstein proposed to measure the rate of return on capital is widely adopted. Here we calculate the rate of return on capital in China by this method. The calculation demonstrates that the rate of retum on all the industrial enterprises is around 6.5 percent from 1996 to 2000, and the average rate of return on state-owned industrial enterprises is lower than the above figure by 1.5 percent during the same period. Finally, we draw a conclusion that the rate of return ranging from 5 to 7 percent is appropriate for the pension reform in China.

关键词： The rate of return on capital pension reform individual account

Tree Expressions for Information Systems

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Journal of Computer science & Technology 2007年第2期22卷 297-307页

作者：赵岷韩素青王珏 NEC Research China Beijing 100080 China Department of Mathematics Taiyuan Normal University Taiyuan 030012 China Institute of Automation Chinese Academy of Sciences Beijing 100080 China

The discernibility matrix is one of the most important approaches to computing positive region, reduct, core and value reduct in rough sets. The subject of this paper is to develop a parallel approach of it, called ＂tree expression＂. Its computational complexity for positive region and reduct is O（m^2 × n） instead of O（m × n^2） in discernibility-matrix-based approach, and is not over O（n^2） for other concepts in rough sets, where rn and n are the numbers of attributes and objects respectively in a given dataset （also called an ＂information system＂ in rough sets）. This approach suits information systems with n ≥ m and containing over one million objects.

关键词： algorithms tree expression reduct theory

ON NEARLY-CONTROLLABLE SUBSPACES OF A CLASS OF DISCRETE-TIME BILINEAR SYSTEMS

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Journal of Systems science & Complexity 2013年第4期26卷 512-526页

作者： TIE Lin School of Automation science and Electrical Engineering Beihang University

If a linear time-invariant system is uncontrollable,then the state space can be decomposed as a direct sum of a controllable subspace and an uncontrollable *** this paper,for a class of discrete-time bilinear systems which are uncontrollable but can be nearly controllable,by studying the nearly-controllable subspaces and defining the near-controllability index,the controllability properties of the systems are fully *** are provided to illustrate the conceptions and results of the paper.

关键词： Bilinear systems discrete-time systems near-controllability near-controllability index,nearly-controllable subspaces.

Superconducting Single-Layer T-Graphene and Novel Synthesis Routes

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Chinese Physics Letters 2019年第9期36卷 46-63页

作者： Qinyan Gu Dingyu Xing Jian Sun national Laboratory of Solid State Microstructures School of Physics and Collaborative Innovation Center of Ad vanced MicrostructuresNanjing UniversityNanjing 210093

Single-layer superconductors are ideal materials for fabricating superconducting nano ***,up to date,very few single-layer elemental superconductors have been predicted and especially no one has been successfully synthesized ***,using crystal structure search techniques and ab initio calculations,we predict that a single-layer planar carbon sheet with 4-and 8-membered rings called T-graphene is a new intrinsic elemental superconductor with superconducting critical temperature(Tc)up to around 20.8 *** importantly,we propose a synthesis route to obtain such a single-layer T-graphene,that is,a T-graphene potassium intercalation compound(C4 K with P4/mmm symmetry)is firstly synthesized at high pressure(>11.5 GPa)and then quenched to ambient condition;and finally,the single-layer T-graphene can be either exfoliated using the electrochemical method from the bulk C4 K,or peeled off from bulk T-graphite C4,where C4 can be obtained from C4 K by evaporating the K ***,we find that the calculated Tc of C4 K is about 30.4 K at 0 GPa,which sets a new record for layered carbon-based *** present findings add a new class of carbon-based *** particular,once the single-layer T-graphene is synthesized,it can pave the way for fabricating superconducting devices together with other 2 D materials using the layer-by-layer growth techniques.

关键词： red Superconducting Single-Layer T-Graphene and Novel Synthesis Routes Graphene

Electromagnetic Scattering and Inverse Scattering of Layered Media with a Slightly Rough Surface

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Chinese Physics Letters 2011年第1期28卷 86-89页

作者： LIN Zhi-Wei XU Xin ZHANG Xiao-Juan FANG Guang-You Key Laboratory for Electromagnetic Radiation and Sen ~ing Technology Institute o1 Electronics Chinese Academy ot Sciences Beijing 100190

An electromagnetic （EA1） scattering model for layered media covered by a 3D infinite rough surface and the corresponding inversion technique are investigated. The work aims at remote sensing the surface roughness and dielectric constant for different depths of bear soil through radar measurement data. The forward problem is carried out by the wave decomposition method. The small perturbation method （SPM） and EM boundary conditions are employed to solve the integral equations introduced by the wave decomposition method. The second-order SPM solution of the scatteringfield is involved in the computation of the forward problem for the first time. The backseattering coefficients of multiple frequencies, multiple angles and multiple polarizations are employed to create a nonlinear optimization problem. A genetic algorithm is introduced to help the inversion procedure approaeh to the global minimum of the cost function. Examples are carried out to validate the inversion technique. The inverion results show good agreement with the forward problem with given parameters and pose good tolerance to the input data with the additive white Gaussian noise.

关键词： Accelerators beams and electromagnetism Statistical physics and nonlinear systems

Speeding Up the GVW Algorithm via a Substituting Method

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Journal of Systems science & Complexity 2019年第1期32卷 205-233页

作者： LI Ting SUN Yao HUANG Zhenyu WANG Dingkang LIN Dongdai SKLOIS Institute of Information EngineeringChinese Academy of Sciences School of Cyber Security University of Chinese Academy of Sciences KLMM Academy of Mathematics and Systems ScienceChinese Academy of Sciences School of Mathematical sciences University of Chinese Academy of Sciences

The GVW algorithm is an effcient signature-based algorithm for computing Gr?bner *** this paper, the authors consider the implementation of the GVW algorithm by using linear algebra,and speed up GVW via a substituting method. As it is well known that, most of the computing time of a Gr?bner basis is spent on reductions of polynomials. Thus, linear algebraic techniques, such as matrix operations, have been used extensively to speed up the implementations. Particularly, one-direction(also called signature-safe) reduction is used in signature-based algorithms, because polynomials(or rows in matrices) with larger signatures can only be reduced by polynomials(rows) with smaller signatures. The authors propose a new method to construct sparser matrices for signature-based algorithms via a substituting method. Speci?cally, instead of only storing the original polynomials in GVW, the authors also record many equivalent but sparser polynomials at the same time. In matrix construction, denser polynomials are substituted by sparser equivalent ones. As the matrices get sparser, they can be eliminated more effciently. Two speci?cal algorithms, Block-GVW and LMGVW, are presented, and their combination is the Sub-GVW algorithm. The correctness of the new proposed method is proved, and the experimental results demonstrate the effciency of this new method.

关键词： Gröbner basis GVW signature-based algorithm time-memory tradeoff

MORAL HAZARD STRATEGY AND QUALITY CONTRACT DESIGN IN A TWO-ECHELON SUPPLY CHAIN

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Journal of Systems science and Systems Engineering 2011年第1期20卷 70-86页

作者： Lilong ZHU Jianxin YOU School of Economics and Management Tongji University Shanghai 200092 China i University Shanghai 200092 China

Based on game theory and principal-agent theory, this paper focuses on how to control product quality and design quality contract in supply chain when moral hazard exists. We set up the supplier and buyer＇s expected profits function model, in which the supplier makes production process investment-level decision and decides on the product quality prevention level, whereas the buyer makes quality evaluation decision and decides on the product quality inspection level. The supplier with a moral hazard of reducing investment level may lack investment in the production process; thus, the buyer will pay the information rent to incentivize the supplier to improve the investment level. The buyer creates the moral hazard of exaggerating the product quality defective rate, who may overinvest in the inspection process. We use the optimal condition to solve supplier＇s first-best investment level, product quality prevention level, and buyer＇s first-best quality inspection level, internal penalty, and apportionment ratio of external failure cost. We also conduct a simulation test that shows the following： When the supplier improves its investment level, its product quality prevention level will increase, and the buyer＇s quality inspection level will decrease. With the improvement in the buyer＇s product quality inspection level, its internal penalty will increase, and the supplier＇s external failure cost will also increase while its expected profits will decrease. Hence, the buyer will design an incentive contract, the expected profits of which will increase, and the whole supply chain＇s joint expected profits function may become an inverse U shape. Finally, we develop a simulation example and propose suggestions for quality control strategy and contract design in the supply chain under the conditions of asymmetric information.

关键词： Supply chain moral hazard quality control contract design principal-agent relationship

Comparative studies of semiconductor saturable absorber mirror mode-locking dynamics in pulsed diode-end-pumped picosecond Nd:GdVO_4 and Nd:YAG lasers

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Chinese Optics Letters 2006年第6期4卷 336-338页

作者：张丙元李港陈檬王国菊王勇刚 College of Laser Engineering Beijing University of Technology College of Physics science and Information Engineering Liaocheng University Institute of Semiconductors Chinese Academy of sciences

Ultrashort pulses were generated in passively mode-locked Nd：YAC and Nd：CdVO4 lasers pumped by a pulsed laser diode with 10-Hz repetition rate. Stable mode-locked pulse trains were produced with the pulse width of 10 ps. The evolution of the mode-locked pulse was observed in the experiment and was discussed in detail. Comparing the pulse evolutions of Nd：YAG and Nd：GdVO4 lasers, we found that the buildup time of the steady-state mode-locking with semiconductor saturable absorber mirrors （SESAMs） was relevant to the upper-state lifetime and the emission cross-section of the gain medium.

关键词： Laser mode locking Laser pulses Mirrors Pumping (laser) Ultrashort pulses

A High-Temperature β-Phase NaMnO2 Stabilized by Cu Doping and Its Na Storage Properties

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Chinese Physics Letters 2018年第4期35卷 132-135页

作者： Li-Wei Jiang Ya-Xiang Lu Yue-Sheng Wang Li-Lu Liu Xing-Guo Qi Cheng-Long Zhao Li-Quan Chen Yong-Sheng Hu Key Laboratory for Renewable Energy Beijing Key Laboratory for New Energy Materials and Devices and BeijingNational Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190 School of Physical sciences University of Chinese Academy of Sciences Beijing 100049

The high-temperature β-phase NaMnO2 is a promising material for Na-ion batteries（NIBs） due to its high capacity and abundant resources. However, the synthesis of phase-pure -NaMnO2 is burdensome and costineffective because it needs to be sintered under oxygen atmosphere at high temperature and followed by a quenching procedure. Here we first report that the pure β phase can be stabilized by Cu-doping and easily synthesized by replacing a proportion of Mn with Cu via a simplified process including sintering in air and cooling to room temperature naturally. Based on the first-principle calculations, the band gap decreases from 0.7 eV to 0.3 eV, which indicates that the electronic conductivity can be improved by Cu-doping. The designed -NaCu（0.1）Mn（0.9）O2 is applied as cathode in NIBs, exhibiting an energy density of 419 Wh/kg and better performance in terms of rate capability and cycling stability than those in the undoped case.

关键词： Na A High-Temperature Phase NaMnO2 Stabilized by Cu Doping and Its Na Storage Properties Mn Cu