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Isomerization of B_6,B_6^- and B_6^+ clusters

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science china Chemistry 2010年第1期53卷 202-209页

作者： WEI GongMin1,PU ZhiFeng2.ZOU Rong3,LI GuoLiang2.3 & LUO Qiong2.3 1Department of Physics,Capital Normal University,beijing 100048,china 2.tate Key {2. of Explosion science and technology beijing Institute of technology,beijing 100081,china 3center for Computational quantum Chemistry,South china Normal University,Guangzhou 510631,china 1. Department of Physics Capital Normal University Beijing 100048 China2. State Key Laboratory of Explosion Science and Technology Beijing Institute of Technology Beijing 100081 China3. Center for Computational Quantum Chemistry South China Normal University Guangzhou 510631 China

The interconversions between isomers with the same spin multiplicity of neutral B6 and charged B6-and B6+ clusters have been investigated at the B3LYP/6-311+G level of theory,including determination of the minimum energy pathways with transition states connecting the corresponding reactants and *** dynamic calculations,2. isomers were optimized,including 11 novel *** order to further refine the energies,single-point B3LYP/6-311+G(3df) calculations were carried out on the corresponding B3LYP/6-311+G geometries of all isomers of B6,B6-and B6+ and the corresponding isomerization transition *** stability of each isomer of B6(singlet and triplet states),B6-(doublet state) and B6+(doublet state) was analyzed from both thermodynamic and dynamic viewpoints.

关键词： B6 transition state intrinsic reaction coordinate barrier height

Conjugate adjoining problem in braid groups and new design of braid-based signatures

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science china({2. sciences) 2010年第3期53卷 524-536页

作者： WANG LiCheng1,2. WANG LiHua2. CAO ZhenFu3, YANG YiXian1 & NIU XinXin1 information Security center, State Key {2. of Networking and Switching technology, beijing University of Posts and Telecommunications, beijing 100876, china 2.7} Institute of information and Communications technology, Tokyo 184-8795, Japan 3Trusted Digital technology {2., Shanghai Jiao Tong University, Shanghai 2.02.0, china 1. information Security center State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing 100876 China2. National Institute of Information and Communications Technology Tokyo 184-8795 Japan3. Trusted Digital Technology Laboratory Shanghai Jiao Tong University Shanghai 200240 China

The development of quantum computation casts serious threats to the securities of most existing public-key cryptosystems. Braid-based cryptography is one of the alternatives that have potential advantages in resisting quantum attacks. In this paper, the state of the art of braid cryptography is surveyed, and then a new cryptographic problem-conjugate adjoining problem related to braid groups is proposed. Based on this problem, we design a new braid-based signature scheme. This scheme is efficient and provably secure in the random oracle model. Further, we present the comparison between braid-based signatures and RSA-based ones. The signing process of the braid-based schemes is more efficient than that of RSA-based ones, while the verifying process of the braid-based ones is observably slow. Hence, braid-based signatures are suitable for scenarios where the signing process has to be as quick as possible but delays are permitted in the verifying process, for example, in off-line e-cash systems. The key sizes in braid-based schemes are considerably large-about 2. bits in the case of secret keys and 12. bits in the case of public keys. However, braid operations are much simpler and more efficient than modular exponential operations. Therefore, braid-based schemes can be embedded into devices with low computational ability and large memory space. The capability of braid cryptosystems to resist currently known quantum attacks is also discussed from the perspective of hidden subgroup problems.

关键词： braid group conjugate adjoining problem digital signature provable security resistance to quantum attack

Packet Scheduling Algorithm for Real-Time Services in Broadband WMAN

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ZTE Communications 2009年第4期7卷 45-48页

作者： Zhang Hanyi, Su Xin (Wireless and Mobile Communication technology R&D center of {2. University, tsinghua national laboratory for information science and technology, beijing 100084 , china )

Packet scheduling algorithm is the key technology to guarantee Quality of Service (QoS) and balance the fairness between users in broadband Wireless Metropolitan Area Network (WMAN). Based on the research of Proportional Fairness (PF) algorithm and Modified Largest Weighted Delay First (M-LWDF) algorithm, a new packet scheduling algorithm for real-time services in broadband WMAN, called Enhanced M-LWDF (EM-LWDF), was proposed. The algorithm phases in new information to measure the load of service queues and updates the state parameters in real-time way, which remarkably improves system *** results show that comparing with M-LWDF algorithm, the proposed algorithm is advantageous in performances of queuing delay and fairness while guaranteeing system throughput.

关键词： Packet Scheduling Algorithm for Real-Time Services in Broadband WMAN QoS OFDMA Simulation real WiMAX IEEE EM

A method of constructing a database-free optimal dynamical system and a global optimal dynamical system

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science china(Physics,Mechanics & Astronomy) 2008年第7期51卷 905-915页

作者： WU ChuiJie1? & WANG Liang2.1 State Key laboratory of Structural Analysis for Industrial Equipment, Dalian University of technology, Dalian 11602.,{2. 2.Research center for Fluid Dynamics, School of science, PLA University of science and technology, Nanjing 2.1101,{2. 1. State Key laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology Dalian 116024 China 2. Research center for Fluid Dynamics School of Science PLA University of Science and Technology Nanjing 211101 China

In this paper, to overcome the drawbacks of POT which minimize the reminder, not only the optimal functional with minimal residual is put forward, but also the method of global optimization is used. Under the condition of large reminder, the optimal bases can also be obtained through the method of POTres without the approaching of initial conditions. In addition, compared with local optimization, the advantage of global optimization is remarkable. On the one hand, we can expect that the dynamical system based on the global optimal bases will include more information than the ones based on the local optimal bases, since the global optimal bases are much more precise than the local optimal bases. On the other hand, from the point of view of error, the global optimal bases are independent of the choice of the object functional and the initial bases.

关键词： dynamical system residual global optimization

Study on NDVI-T_s space by combining LAI and evapotranspiration

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science china Earth sciences 2006年第7期49卷 747-754页

作者： HAN Lijuan1,2.3, WANG Pengxin4, YANG Hua1,2.3, LIU Shaomin1,2.3 & WANG Jindi1,2.3 1. Research center for Remote Sensing and GIS, School of Geography, beijing Normal University, beijing 100875, china 2. State Key laboratory of Remote Sensing science, beijing 100875, china 3. beijing Key laboratory for Remote Sensing of Environment and Digital Cities, beijing 100875, china 4. Department of {12. Management, College of {12. and Electronic Engineering, china Agricultural University, beijing 100083, china 1. Research center for Remote Sensing and GIS School of Geography Beijing Normal University Beijing 100875 China 2. State Key laboratory of Remote Sensing science Beijing 100875 China 3. beijing Key laboratory for Remote Sensing of Environment and Digital Cities Beijing 100875 China 4. Department of information Management College of Information and Electronic Engineering China Agricultural University Beijing 100083 China

This paper focuses on interpreting the different spatial relationships between NDVI and Ts, a triangular or a trapezoid, and on analyzing transformation conditions, the physical and ecological meanings of the vegetation index-surface temperature space as well. Further, we use the Tempera-ture-Vegetation Dryness Index (TVDI) to explain the existent meaning of a triangular space after NDVI reaches its saturated state by employing the relationships between NDVI, LAI and evapotranspiration. The specific relations between NDVI and Ts are useful for describing, validating and updating land surface models.

关键词： NDVI, land surface temperature, evapotranspiration, leave area index.

Absence of State Collapse and Revival in a Superconducting Charge Qubit

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Communications in Theoretical Physics 2007年第12期48卷 1029-1032页

作者： HUO Wen-Yi~1 and LONG Gui-Lu~(1,2.3)~1 Department of Physics amd Key laboratory for quantum {2. and Measurements,tsinghua University,beijing100084,china~2.Key laboratory for Atomic and Molecular Nanosciences,tsinghua University,beijing 100084,china~3 national laboratory for {2. science and technology,Hsinghua University,beijing 100084,china Department of Physics amd Key laboratory for quantum {2. and Measurements Tsinghua University Key laboratory for Atomic and Molecular Nanosciences Tsinghua University national laboratory for {2. science and technology Hsinghua Univers

The Hamiltonian of a superconducting charge qubit with a configuration of dc SQUID contains an interac-tion between the LC oscillator part and charge *** interaction may leads to quantum state collapse and revivalwhich degrades the charge qubits and leads to serious *** analysis shows that the existing charge qubitparameters do not lead to this phenomenon,which is very good for the superconducting charge

关键词： quantum computer superconducting charge qubit absence and revival

Black-box testing based on colorful taint analysis

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science china({2. sciences) 2012年第1期55卷 171-183页

作者： CHEN Kai1,2.3,FENG DengGuo1,SU PuRui1&ZHANG YingJun1,2.3 1State Key laboratory of information Security,Institute of Software,Chinese Academy of {2.,beijing 100190,china 2.tate Key laboratory of information Security,Graduate University of Chinese Academy of {2.s,beijing 100049,china 3national Engineering Research center of information Security,beijing 100190,china 1. State Key laboratory of information Security Institute of Software Chinese Academy of Science Beijing 100190 China2. State Key Laboratory of Information Security Graduate University of Chinese Academy of Sciences Beijing 100049 China3. National Engineering Research Center of Information Security Beijing 100190 China

Software vulnerability detection is one of the most important methods for guaranteeing software *** main classes of methods can detect vulnerabilities in binary files:white-box testing and black-box *** former needs to construct and solve path constraints to detect *** has two main drawbacks:path exploding and complexity of *** latter often aimlessly exhausts various inputs to test binary *** paper combines both testing methods to detect vulnerabilities in binary *** analyzing the input elements that aect check condition corresponding to a certain check point,we can generate one class of inputs that get to the check point to increase fuzzing *** analyzing the relationship between guard conditions and check condition,the redundant check points are *** taint analysis method(CTAM)is proposed to compute guard conditions,which is more ecient than traditional taint analysis method(TTAM).We implemented a prototype and made several experiments on *** results showed that our method could increase the eciency of black-box testing.

关键词： software testing vulnerability detection dynamic testing black-box testing colorful taint analysis

Effects of disinhibition on spatiotemporal pattern of neuronal first recruitment in neuronal networks

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Progress in Natural science:Materials International 2009年第5期19卷 615-621页

作者： Liangbin Pana,b,c,1, Xindong Songa,b,c,1, Guangxin Xiang a,b,c, Jing Zhua,b,c, Jing Cheng a,b,c,d,a Medical Systems Biology Research center, tsinghua University School of Medicine,{2., china b Department of Biological sciences and Biotechnology, tsinghua University,{2., china c national Engineering Research center for beijing Biochip technology, 18 Life science Parkway, beijing 102.06, china d State Key laboratory of Biomembrane and Membrane Biotechnology, tsinghua University,{2., china [a]Medical Systems Biology Research center Tsinghua University School of Medicine Beijing 100084 China [b]Department of Biological Sciences and Biotechnology Tsinghua University Beijing 100084 China [c]National Engineering Research Center for Beijing Biochip Technology 18 Life Science Parkway Beijing 102206 China [d]State Key Laboratory of Biomembrane and Membrane Biotechnology Tsinghua University Beijing 100084 China

The propagation of neuronal activities is a key feature to understanding information processing in networks. The analysis based on first-spikes of bursts in turn plays an important role in the research of neuronal activity propagation. Our focus here is to investigate how spatiotemporal patterns of neuronal first-spikes are affected by disinhibition. Multi-electrode arrays were used to record stimulation-evoked bursts of multiple neurons in randomly cultured neuronal networks. Both the precise timing of and the rank relationships between first-spikes were analyzed. Compared with evoked bursts in the network’s native state, the precise first-spike latencies in its dis-inhibited state are more consistent and the propagation of its bursting activities is much faster. Additional points of interest are that disinhibited neuronal networks can be evoked to generate stable and distinguishable neuronal first recruitment spatiotemporal patterns specific to the stimulation site, and that the disinhibition may cause the original spatiotemporal patterns to change in a heterogeneous manner with regards to different propagation pathways.

关键词： Neuronal recruitment Spatiotemporal pattern Disinhibition Network Multi-electrode array

Investigation of fine and complex vortex circulation structures

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science china Earth sciences 2010年第10期53卷 1552-1558页

作者： LUO ZheXian1,MA GeLan1 & PING Fan2.1 Remote Sensing College,Nanjing University of information science and {2.,Nanjing 2.0044,china 2.laboratory of Cloud-Precipitation Physics and Severe Storms(LACS),Institute of Atmospheric Physics,Chinese Academy of sciences,beijing 10002.,china 1. Remote Sensing College Nanjing University of Information Science and Technology Nanjing 210044 China2. Laboratory of Cloud-Precipitation Physics and Severe Storms (LACS) Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

The formation and evolution of fine and complicated vortex circulation structures were investigated using a two-dimensional quasi-geostrophic barotropic model *** find that the highly localized asymmetric and complex configuration of energy transfer flux between large-and small-scale components is caused by the nonlinear interaction between a large-scale vortex with an initial axi-symmetric flow and four beta meso-scale *** complex structure is characterized by a fine pattern,which contains seven closed systems with spatial scales of less than 100 km,embedded in a positive flux wave train and a negative wave train,*** average wind speed decreased with time in the positive flux region,but was nearly unchanged in the negative flux *** pattern reveals the evolutionary asymmetry and localization of wind speed of the major *** track of the major vortex center has a trend toward the center of the negative flux center,indicating that there is a certain relation between the complex structure of the energy transfer flux and the motion of the major vortex *** results imply that the formation and evolution of the fine and complex structure should be attributed to the nonlinear interaction between the vortices at different spatial scales.

关键词： vortex complex structure non-linear interaction energy cascade