检索结果-南通市图书馆

On the fluorescence of C_60 at room temperature

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2010年第1期53卷 95-99页

作者： ZHANG Fang & ZHANG XiaoLing department of Chemistry, beijing institute of technology, beijing 100081, china department of Chemistry Beijing Institute of Technology Beijing China

The fluorescence properties of C 60 in different organic solvents have been investigated at room temperature. Three fluorescence emission centers are discovered and ascribed to different aggregations of C 60 in solvent. A series of blue fluorescence peaks centered at 440 nm derive from C 60 nanoparticles; a distinctive yellow-green fluorescence band in 575 nm region arises from the aggregates of C 60 nanoparticles; a more informative salmon fluorescence band around 700 nm originates from C 60 microcrystals. And the distinct configurations of C 60 aggregations are closely associated with the characteristic interaction between C 60 and solvent molecules.

关键词： C 60 fluorescence TEM confocal fluorescence spectroscopy

Dimension reduction based on weighted variance estimate

在线全文

学校读者我要写书评

暂无评论

Science china mathematics 2009年第3期52卷 539-560页

作者： ZHAO JunLong1 & XU XingZhong2 1 department of mathematics, Beihang University Laboratory of mathematics, Information and Behavior of the Ministry of Education, beijing 100083, china 2 department of mathematics, beijing institute of technology, beijing 100081, china department of mathematics Beihang University Laboratory of mathematics Information and Behavior of the Ministry of Education Beijing China department of mathematics Beijing Institute of Technology Beijing China

In this paper, we propose a new estimate for dimension reduction, called the weighted variance estimate (WVE), which includes Sliced Average Variance Estimate (SAVE) as a special case. Bootstrap method is used to select the best estimate from the WVE and to estimate the structure dimension. And this selected best estimate usually performs better than the existing methods such as Sliced Inverse Regression (SIR), SAVE, etc. Many methods such as SIR, SAVE, etc. usually put the same weight on each observation to estimate central subspace (CS). By introducing a weight function, WVE puts different weights on different observations according to distance of observations from CS. The weight function makes WVE have very good performance in general and complicated situations, for example, the distribution of regressor deviating severely from elliptical distribution which is the base of many methods, such as SIR, etc. And compared with many existing methods, WVE is insensitive to the distribution of the regressor. The consistency of the WVE is established. Simulations to compare the performances of WVE with other existing methods confirm the advantage of WVE.

关键词： central subspace contour regression sliced average variance estimate sliced inverse regression sufficient dimension reduction weight function 62G08 62H05

The spectrum for large sets of pure directed triple systems

在线全文

学校读者我要写书评

暂无评论

Science china mathematics 2006年第8期49卷 1103-1127页

作者： ZHOU Junling, CHANG Yanxun & Jl Lijun institute of mathematics, beijing Jiaotong University, beijing 100044, china department of mathematics, Suzhou University, Suzhou 215006, china institute of mathematics Beijing Jiaotong University Beijing China department of mathematics Suzhou University Suzhou China

An LPDTS(υ) is a collection of 3(υ - 2) disjoint pure directed triple systems on the same set of υ elements. It is showed in Tian's doctoral thesis that there exists an LPDTS(υ) for υ≡ 0,4 (mod 6), υ≥ 4. In this paper, we establish the existence of an LPDTS(υ) for υ≡ 1, 3 (mod 6), υ＞ 3. Thus the spectrum for LPDTS(υ) is completely determined to be the set {υ:υ≡0, 1 (mod 3),υ≥4}.

关键词： large set, oriented triple system, pure, directed candelabra system.

Weighted weak type estimates for commutators of the Marcinkiewicz integrals

在线全文

学校读者我要写书评

暂无评论

Science china mathematics 2004年第1期47卷 83-95页

作者： DING Yong, LU Shanzhen & ZHANG Pudepartment of mathematics, beijing Normal University, beijing 100875, china department of Information and Computing Science, Zhejiang institute of Science and technology, Hangzhou 310033, china department of mathematics Beijing Normal University Beijing China department of Information and Computing Science Zhejiang Institute of Science and Technology Hangzhou China

In this paper the authors give the weighted weak LlogL type estimates for a class of the higher order commutator generated by the Marcinkiewicz integral and a BMO function. In addition, the weak type norm inequalities... 详细信息

关键词： Marcinkiewicz integral, commutator, Ap weight, weak type estimate.

Monomial Hopf algebras over fields of positive characteristic

在线全文

学校读者我要写书评

暂无评论

Science china mathematics 2006年第3期49卷 320-329页

作者： LIU Gongxiang & YE Yu institute of mathematics, Academy of mathematics and Systems Science, Chinese Academy of Sciences, beijing 100080, china department of mathematics, University of Science and technology of china, Hefei 230026, china institute of mathematics Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing China department of mathematics University of Science and Technology of China Hefei China

In this paper, we study the structures of monomial Hopf algebras over a field of positive characteristic. A necessary and sufficient condition for the monomial coalgebra Cd(n) to admit Hopf structures is given here, and if it is the case, all graded Hopf structures on Cd(n)are completely classified. Moreover, we construct a Hopf algebras filtration on Cd(n) which will help us to discuss a conjecture posed by Andruskiewitsch and Schneider. Finally combined with a theorem by Montgomery, we give the structure theorem for all monomial Hopf algebras.

关键词： monomial coalgebra, Gaussian binomial coefficient, monomial Hopf algebra.

Reconfigurable design and implementation of the MD6 Hash function

在线全文

学校读者我要写书评

暂无评论

The Journal of china Universities of Posts and Telecommunications 2010年第2期17卷 109-115页

作者： GAO Xian-wei department of Electronic and Information Engineering,beijing Electronic Science and technology institute,beijing 100070,china department of Electronic and Information Engineering Beijing Electronic Science and Technology Institute Beijing 100070 China

Efficient reconfigurable field programmable gate array （FPGA） architectures for the MD6-224/256/384/512 Hash algorithm are proposed in this article. The basic iterative compact design requires 923 ALMs and achieves a throughput ranging from 225 Mbit/s to 394 Mbit/s at a maximum frequency of 198 MHz. The 32-step-urtrolled high-throughput design requires 7 090 ALMs and achieves a throughput ranges from 5 776 Mbit/s to 9 490 Mbit/s at a maximum frequency of 173 MHz. The simulation results show that high flexibility and efficient FPGA implementation of the MD6 Hash function is achieved.

关键词： SHA-3 MD6 reconfigurable iterative loop-unrolling

On the periodic solutions of a type of differential-iterative equations

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1998年第3期43卷 204-206页

作者： GE Weigao 1, LIU Zhengrong 2 and YU Yuanhong 3 1. department of Applied mathematics, beijing institute of technology, beijing 100081, china 2. department of mathematics, Yunnan University, Kunming 650091, china 3. institute of Applied mathematics, C department of Applied mathematics Beijing Institute of Technology Beijing China department of mathematics Yunnan University Kunming China institute of Applied mathematics Chinese Academy of Sciences Beijing China

Sufficient conditions for the existence of periodic solutions to a type of nonautonomous differential_iterative equations are given.

关键词： differential_iterative equation periodic solution fixed point.

THE POPULATION DYNAMICS WITH N-INTERSECTIONS

在线全文

学校读者我要写书评

暂无评论

Systems Science and Mathematical Sciences 1994年第2期7卷 177-186页

作者： GUO Baozhu(department of Applied mathematics beijing institute of technology,beijing 100081, china)

ＴＨＥＰＯＰＵＬＡＴＩＯＮＤＹＮＡＭＩＣＳＷＩＴＨＮ－ＩＮＴＥＲＳＥＣＴＩＯＮＳ￥ＧＵＯＢａｏｚｈｕ（ＤｅｐａｒｔｍｅｎｔｏｆＡｐｐｌｉｅｄＭａｔｈｅｍａｔｉｃｓＢｅｉｊｉｎｇＩｎｓｔｉｔｕｔｅｏｆＴｅｃｈｎｏｌｏｇ... 详细信息

ＴＨＥＰＯＰＵＬＡＴＩＯＮＤＹＮＡＭＩＣＳＷＩＴＨＮ－ＩＮＴＥＲＳＥＣＴＩＯＮＳ￥ＧＵＯＢａｏｚｈｕ（ＤｅｐａｒｔｍｅｎｔｏｆＡｐｐｌｉｅｄＭａｔｈｅｍａｔｉｃｓＢｅｉｊｉｎｇＩｎｓｔｉｔｕｔｅｏｆＴｅｃｈｎｏｌｏｇｙ，Ｂｅｉｊｉｎｇ１０００８１，Ｃ...

关键词： Population dynamics stable population logistic model

Central limit theorem for the occupation time of catalyticsuper-Brownian motion

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1998年第24期43卷 2035-2040页

作者： HONG Wenming department of mathematics, beijing Normal University, beijing 100875, china Corresponding address: institute of mathematics, Shantou University, Shantou 515063, china department of mathematics Beijing Normal University Beijing China

The catalytic super_Brownian motion has been considered. If both the catalytic medium process Q and CSBM started with Lebesgue measure λ, the central limit theorem for occupation time of CSBM has been obtained in dim... 详细信息

关键词： branching rate functional Brownian collision local time catalytic super_Brownian motion occupation time central limit theorem.