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Carbon isotope ratios of C_(4) plants in loess areas of North China

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science China Earth sciences 2006年第1期49卷 97-102页

作者： WANG Guoan1,2,3. HAN Jiamao 2, ZHOU Liping3. XIONG Xiaogang4, TAN Ming2, WU Zhenhai5 & PENG Jun6 1. Department of Plant Nutrition, China Agricultural university, beijing 100094, China 2. institute of Geology and Geophysics, Chinese Academy of {3.s, beijing 100029, China 3. college of Environmental {3.s, MOE Laboratory for Earth Surface Processes, peking university, beijing 100871, China 4. institute of Botany, Chinese Academy of {3.s, beijing 100093. China 5. Northwest Sci-Tech university of Agriculture and Forestry, Yangling 712100, China 6. Network Center, China Agricultural university, beijing 100094, China Department of Plant Nutrition China Agricultural University Beijing China institute of Geology and Geophysics Chinese Academy of Sciences Beijing China college of Environmental sciences MOE Laboratory for Earth Surface Processes Peking University Beijing China institute of Botany Chinese Academy of Sciences Beijing China Northwest Sci-Tech university of Agriculture and Forestry Yangling China Network Center China Agricultural University Beijing China

Carbon isotope ratios (δ^(13.C) of 89 C_4 plant samples were determined fromthe loess area in North China. δ^(13.C values vary between -10.5per thousand and -14.6per thousandwith a mean of -12.6per thousand. Along a precipitation gradient from the semi-moist area to thesemiarid area, then to the arid area, the δ^(13.C values of C_4 plants show a slight decreasingtrend. The δ^(13.C values of C_4 plants in the dry season are found lower than those in the wetseason. These trends are opposite to those observed for C_3.species.

关键词： C4 plants, carbon isotope ratios, loess area.

Bursting of Morris-Lecar neuronal model with current-feedback control

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science China(Technological sciences) 2009年第3期52卷 771-781页

作者： DUAN LiXia1, LU QiShao2 & CHENG DaiZhan3.1 college of science, North China university of Technology, {3. 100144, China 2 School of science, {3. university of Aeronautics and Astronautics, {3. 100191, China 3.institute of Systems science, Chinese Academy of sciences, {3. 100190, China college of science North China University of Technology Beijing China School of science Beijing University of Aeronautics and Astronautics Beijing China institute of Systems science Chinese Academy of Sciences Beijing China

The Morris-Lecar (ML) neuronal model with current-feedback control is considered as a typical fast-slow dynamical system to study the combined influences of the reversal potential VCa of Ca2+ and the feedback current I on the generation and transition of different bursting oscillations. Two-parameter bifurcation analysis of the fast subsystem is performed in the parameter (I, VCa)-plane at first. Three important codimension-2 bifurcation points and some codimension-1 bifurcation curves are obtained which enable one to determine the parameter regions for different types of bursting. Next, we further divide the control parameter (V0, VCa)-plane into five different bursting regions, namely, the "fold/fold" bursting region R1, the "fold/Hopf" bursting region R2, the "fold/homoclinic" bursting region R3. the "subHopf/homoclinic" bursting region R4 and the "subHopf/subHopf" bursting region R5, as well as a silence region R6. Codimension-1 and -2 bifurcations are responsible for explanation of transition mechanisms between different types of bursting. The results are instructive for further understanding the dynamical behavior and mechanisms of complex firing activities and information processing in biological nervous systems.

关键词： neuron bursting bifurcation fast-slow dynamics analysis codimension

One-pot synthesis of crystalline SnO_2 nanoparticles and their low-temperature ethanol sensing characteristics

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science China(Physics,Mechanics & Astronomy) 2009年第10期52卷 1601-1605页

作者： CHEN YuJin1,2,3.ZHU ChunLing4,WANG LiJiao3.& WANG TaiHong2 1 School of Materials science and Engineering,beijing institute of Technology,beijing 100081,China 2 Micro-Nano Technologies Research Center,Hunan university,Changsha 410082,China 3.college of science,Harbin Engineering university,Harbin 150001,China 4 college of Material science and Chemical Engineering,Harbin Engineering university,Harbin 150001,China School of Materials science and Engineering Beijing Institute of Technology Beijing China Micro-Nano Technologies Research Center Hunan University Changsha China college of science Harbin Engineering University Harbin China college of Material science and Chemical Engineering Harbin Engineering University Harbin China

Crystalline SnO2 nanoparticles(NPs) with a diameter less than 6 nm are synthesized using potassium stannate trihydrate as the precursor in a basic *** synthesized NPs can detect ethanol at a ppm level even at 100℃.Furthermore,the NPs have good selectivity to *** excellent ethanol sensing performances are attributed to the small size effect according to the space-charge model.

关键词： SnO2 nanoparticles sensing characteristics

A new DNA algorithm to solve graph coloring problem

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Progress in Natural science:Materials International 2007年第6期17卷 733-738页

作者： Jiang Xingpeng1, Li Yin2, Meng Ya3.and Meng Dazhi2(1. National Laboratory of Pattern Recognition,institute of Automation, Chinese Academy of sciences, beijing 100080, China 2. {3. of Applied sciences, beijing university of Technology, beijing 100022, China 3. School of science, beijing institute of Technology, beijing 100081, China) National Laboratory of Pattern Recognition Institute of Automation Chinese Academy of Sciences Beijing 100080 China college of Applied sciences Beijing University of Technology Beijing 100022 China School of science Beijing Institute of Technology Beijing 100081 China

Using a small quantity of DNA molecules and little experimental time to solve complex problems successfully is a goal of DNA computing. Some NP-hard problems have been solved by DNA computing with lower time complexity than conventional computing. However, this advantage often brings higher space complexity and needs a large number of DNA encoding molecules. One example is graph coloring problem. Current DNA algorithms need exponentially increasing DNA encoding strands with the growing of problem size. Here we propose a new DNA algorithm of graph coloring problem based on the proof of four-color theorem. This algorithm has good properties of needing a relatively small number of operations in polynomial time and needing a small number of DNA encoding molecules (we need only 6R DNA encoding molecules if the number of regions in a graph is R).

关键词： DNA computing NP-hard problem graph coloring problem.

Synthesis and magnetic properties of CdS/α-Fe_2O_3.hierarchical nanostructures

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science China(Physics,Mechanics & Astronomy) 2009年第7期52卷 997-1002页

作者： CHEN YuJin1,2,3. SHI XiaoLing1, CAO MaoSheng1 & ZHU ChunLing4 1 School of Materials science and Engineering, beijing institute of Technology, beijing 100081, China 2 Micro-Nano Technologies Research Center, Hunan university, Changsha 410082, China 3.college of science, Harbin Engineering university, Harbin 150001, China 4 college of Material science and Chemical Engineering, Harbin Engineering university, Harbin 150001, China School of Materials science and Engineering Beijing Institute of Technology Beijing China Micro-Nano Technologies Research Center Hunan University Changsha China college of science Harbin Engineering University Harbin China college of Material science and Chemical Engineering Harbin Engineering University Harbin China

CdS/α-Fe2O3.hierarchical nanostructures, where the CdS nanorods grow irregularly on the side surface of α-Fe2O3.nanorods, were synthesized via a three-step process. The diameters and lengths of CdS nanorods can be tuned by changing the ethylenediamine (EDA) and Cd ion concentrations. The magnetic investigations by superconducting quantum interference device indicate that the hierarchical nanostructures have an Morin transition at lower temperature (23. K) than that of the single bulk α-Fe2O3.materials (263.K). Importantly, the hierarchical nanostructures exhibit weakly ferromagnetic characteristics at 3.0 K. A sharp peak assigned to the surface trap induced emission are observed in room temperature PL spectra. Combining with the optoelectronic properties of CdS, the CdS/ α-Fe2O3.hierarchical nanostructures may be used as multi-functional materials for optoelectronic and magnetic devices.

关键词： α-Fe2O3 CdS hierarchical nanostructures magnetic properties

Synthesis and thermodynamic analysis of nano-La2O3

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Progress in Natural science:Materials International 2007年第7期17卷 838-844页

作者： Liu Lili~(1,2) Tang Jie~2 Li Yuxiang~1 Zhang Mei~(1**) Wang Xidong~(1,3. (1.Department of Physical Chemistry,university of science and Technology beijing,beijing 100083.China 2.National institute for Materials science,Segen 1-2-1,Tsukuba 3.5-0047,Japan 3.college of Engineering,beijing university,beijing 100871,China) Department of Physical Chemistry University of Science and Technology Beijing Beijing 100083 China National institute for Materials science Segen 1-2-1 Tsukuba 305-0047 Japan college of Engineering Beijing University Beijing 100871 China

The thermodynamic parameters of La（NO3.3.nd La（OH）3.re evaluated and the thermodynamics of nano-La2O3.yn- thetic process is *** the base of thermodynamic analysis,La2O3.ano-powders are prepared by the sol-gel method and the experi- ment scheme is designed by an orthogonal *** dry-gelatin is analyzed with differential thermal analysis/thermo-gravimetric analy- sis（TGA-DTA）and X-ray diffraction *** microstructure of nano-La2O3.owders is observed by transmission dectron micro- *** synthetic parameters affecting the average grain size and dispersivity of nano-La2O3.articles are experimentally examined and *** the results indicate that nano-La2O3.articles well-dispersed are obtained and the average grain size is in the range of 20—50 nm.

关键词： nano-La2O3 sol-gel thermodynamic analysis

Probabilistic composition of cone-based cardinal direction relations

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science China(Technological sciences) 2008年第S1期51卷 81-90页

作者： LIU Yu1,TIAN Yuan1 & WENG JingNong2 1 institute of Remote Sensing and Geographical Information Systems,peking university,beijing 100871,China 2 {3. of Software,Beihang university,beijing 100083.China institute of Remote Sensing and Geographical Information Systems Peking University Beijing China college of Software Beihang University Beijing China

Composition tables play a significant role in qualitative spatial reasoning (QSR). At present,a couple of composition tables focusing on various spatial relations have been developed in a qualitative approach. However,the spatial reasoning proc-esses are usually not purely qualitative in everyday life,where probability is one important issue that should be considered. In this paper,the probabilistic compo-sitions of cone-based cardinal direction relations (CDR) are discussed and esti-mated by making some assumptions. Consequently,the form of composition result turns to be {(R1,P1),(R2,P2),…,(Rn,Pn)},where Pi is the probability associated with relation Ri. Employing the area integral method,the probabilities in each composi-tion case can be computed with the assumption that the target object is uniformly distributed in the corresponding cone regions.

关键词： spatial reasoning cardinal direction relations probabilistic composition

TARTARIC ACID TEMPLATED SYNTHESIS OF MESOPOROUS Ti-INCORPORATED SILICA AND ITS CATALYTIC ACTIVITY FOR THE RING-OPENING POLYMERIZATION OF ε-CAPROLACTONE

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Chinese Journal of Polymer science 2002年第4期20卷 361-368页

作者： Jie-bin Pang Chang-ming Dong Kun-yuan Qiu Yen Wei Department of Polymer science and Engineering college of Chemistry and molecular Engineering {3. beijing 100871, China Department of Chemistry Drexel university Philadelphia, Pennsylvania 19104, USA Department of Polymer science and Engineering College of Chemistry and Molecular Engineering Peking University 北京 100871 Department of Chemistry Drexel University 美国 Pennsylvania

Ti-incorporated mesoporous silica materials with pore diameters of 3.4 nm have been prepared via the co-hydrolysis and co-condensation reactions, that is the sol-gel reactions, of titanium (IV) tetrabutoxide and tetraethylorthosilicate in the presence of tartaric acid as template, followed by extraction with ethanol to remove the templatemolecules. The materials were characterized in detail by Fourier transform infrared spectroscopy, nitrogen adsorption-desorption test, powder X-ray diffraction, transmission electron microscopy and X-ray energy dispersive spectroscopy. Theresults indicate that the Ti-containing silica materials have large specific surface areas (ca. 1200 m^2 g^(-1)) and pore volumes(ca. 0.900 cm^3.g^(-1)). The mesoporosity arises from disordered interconnecting channels or pores. The Ti-incorporated silicasexhibit catalytic activity for the ring-opening polymerization of ε-caprolactone, otherwise, the pure mesoporous silicamaterial shows no catalytic activity under the identical conditions.

关键词： Mesoporous material Ti-incorporated silica ε-Caprolactone Ring-opening polymerization Sol-gel reactions

Multiparty simultaneous quantum identity authentication with secret sharing

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science China(Physics,Mechanics & Astronomy) 2008年第3期51卷 321-327页

作者： YANG YuGuang1,2,WEN QiaoYan3.& ZHANG Xing4,5 1 college of Computer science and Technology,beijing {3. of Technology,beijing 100022,China 2 State Key Laboratory of Information Security (Graduate {3. of the Chinese Academy of sciences),beijing 100049,China 3.School of science,beijing {3. of Posts and Telecommunications,beijing 100876,China 4 institute of Electronic Technology,Information Engineering {3.,Zhengzhou 450004,China 5 Trusted Computing Laboratory,beijing {3. of Technology,beijing 100022,China college of Computer science and Technology Beijing University of Technology Beijing China State Key Laboratory of Information Security (Graduate university of the Chinese Academy of sciences) Beijing China School of science Beijing University of Posts and Telecommunications Beijing China institute of Electronic Technology Information Engineering University Zhengzhou China Trusted Computing Laboratory Beijing University of Technology Beijing China

Two multiparty simultaneous quantum identity authentication (MSQIA) protocols based on secret sharing are presented. All the users can be authenticated by a trusted third party (TTP) simultaneously. In the first protocol,the TTP shares a random key K with all the users using quantum secret sharing. The ith share acts as the authentication key of the ith user. When it is necessary to perform MSQIA,the TTP generates a random number R secretly and sends a sequence of single photons encoded with K and R to all the users. According to his share,each user performs the corresponding unitary operations on the single photon sequence sequentially. At last,the TTP can judge whether the impersonator exists. The sec-ond protocol is a modified version with a circular structure. The two protocols can be efficiently used for MSQIA in a network. They are feasible with current technol-ogy.

关键词： quantum identity authentication secret sharing quantum cryptography