检索结果-南通市图书馆

Theoretical Study on the Triplet-sensitized Photolysis of 2,5-Dimethylfuran

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2005年第10期24卷 1145-1151页

作者： WANG Yan-xia ye Song Department of Chemistry Yunnan University Kunming 650091 China

In the present work, the triplet-sensitized photolysis of 2,5-dimethylfuran has been investigated with the complete active space SCF （CASSCF） molecular orbital method. Two different reaction routes through diradical and carbene intermediates respectively have been systematically studied, and the reaction via carbene intermediate is the major part well compatible with experiment. Geometries of minima and transition states on S0T1 surface were fully optimized at the CAS level with a 6-31G^＊ basis set. A multireference MP2 algorithm that has been implemented in Gaussian was used to correct the energetics for dynamic correlation. Four intersystem crossing points have been located and discussed, and two of them are efficient. Our computation indicates that the reaction must occur on the triplet-excited state.

关键词： CASSCF photolysis intersystem crossing point reaction path

Multi-harmonic forced vibration and resonance of simple beams to moving vehicles

在线全文

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2023年第7期17卷 981-993页

作者： Zhi SUN Limin SUN ye xia State Key Laboratory for Disaster Reduction in Civil Engineering Shanghai 200092China Department of Bridge Engineering Tongji UniversityShanghai 200092China

This study modeled the moving-vehicle-induced forcing excitation on a single-span prismatic bridge as a multiple frequency-multiplication harmonic load on the modal coordinates of a linear elastic simple Euler–Bernoulli beam,and investigated the forced modal oscillation and resonance behavior of this type of dynamic *** forced modal responses consist of multiple frequency-multiplication steady-state harmonics and one damped mono-frequency complementary *** analysis revealed that a moving load induces high-harmonic forced resonance amplification when the moving speed is *** verify the occurrence of high-harmonic forced resonance,numerical tests were conducted on single-span simple beams based on structural modeling using the finite element method(FEM)and a moving sprung-mass oscillator vehicle *** forced resonance amplification characteristics of the fundamental mode for beam response estimation are presented with consideration to different end restraint *** results reveal that the high-harmonic forced resonance may be significant for the investigated beams subjected to vehicle loads moving at specific low *** the investigated single-span simple beams,the moving vehicle carriage heaving oscillation modulates the beam modal frequency,but does not induce notable variation of the modal oscillation harmonic structure for the cases that vehicle of small mass moves in low speed.

关键词： forced vibration linear Euler beam moving load harmonic structure frequency modulation end restraints

A Decode-and-Forward Scheme for LDPC Coded Three-Way Relay Fading Channels

在线全文

学校读者我要写书评

暂无评论

China Communications 2015年第8期12卷 46-54页

作者： ye xia GAO Feifei Department of Computer Science & Information Management Wenzhou Medical University Department of Automation Tsinghua University State Key Lab of Intelligent Technologies and Systems Tsinghua National Laboratory for Information Science and Technology (TNList)

In this paper a low-density pairwise check(LDPC) coded three-way relay system is considered, where three user nodes desire to exchange messages with the help of one relay node. Since physical-layer network coding is applied, two time slots are sufficient for one round information exchange. In this paper, we present a decode-and-forward(DF) scheme based on joint LDPC decoding for three-way relay channels, where relay decoder partially decodes the network code rather than fully decodes all the user messages. Simulation results show that the new DF scheme considerably outperforms other common schemes in three-way relay fading channels.

关键词： three-way relay channel physicallayer network coding LDPC codes decode-and forward

Theoretical Study of the Photochemical Reaction Mechanism of Bicyclo[4.1.0]heptane

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2006年第4期22卷 520-523页

作者： WANG Yan-xia ye Song Department of Chemistry Yunnan University Kunming 650091 P. R. China

The photochemical reaction of bicyclo[4.1.0]heptane was studied at the complete active space SCF（CASSCF） level with a 6-31G^＊ basis set. A muhireference MP2 algorithm that has been implemented in the Gaussian program was used to correct the energetics for the dynamic correlation. Starting from the Franck-Condon excitation of bicyclo [ 4.1.0 ] heptane, the reaction is via two bonds＇ breakage to give rise to 1,6-heptdiene. One internal conversion （IC） and two intersystem crossing points（ISC） were located and are discussed separately. The reaction proceeds to its own characteristic product on the ground state.

关键词： CASSCF Intersystem crossing Photochemical reaction mechanism Internal conversion Bicyclo-[ 4.1.0 ] heptane 1-6 Heptadiene

Eigenfrequency analysis of bridges using a smartphone and a novel low-cost accelerometer prototype

在线全文

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2024年第2期18卷 202-215页

作者： Seyedmilad KOMARIZADEHASL ye xia Mahyad KOMARY Fidel LOZANO Department of Civil and Environment Engineering Universitat Politècnica de CatalunyaBarcelona 08034Spain Department of Bridge Engineering Tongji UniversityShanghai 200092China Department of Civil Engineering Universidad de Castilla-La ManchaCiudad Real 13071Spain

Researchers are paying increasing attention to the development of low-cost and microcontroller-based accelerometers,in order to make structural health monitoring feasible for conventional bridges with limited monitoring *** with the low-cost sensor development,the use of the embedded accelerometers of smartphones for eigenfrequency analysis of bridges is becoming popular in the civil engineering *** paper,for the first time in the literature,studies these two promising technologies by comparing the noise density and eigenfrequency analysis of a self-developed,validated and calibrated low-cost Internet of things based accelerometer LARA(low cost adaptable reliable accelerometer)with those of a state of the art smartphone(iPhone XR).The eigenfrequency analysis of a footbridge in San Sebastian,Spain,showed that the embedded accelerometer of the iPhone XR can measure the natural frequencies of the under study bridge.

关键词： smartphone modal analysis eigenfrequency analysis low-cost accelerometers Arduino Raspberry Internet of things

The Extension of a Quantized Borcherds Superalgebra by a Hopf Algebra

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2016年第3期32卷 363-372页

作者： Li xia ye Zhi xiang WU Department of Mathematics Zhejiang International Studies University School of Mathematical Sciences Zhejiang University

A two-parameter quantum group is obtained from the usual enveloping algebra by adding two commutative grouplike elements. In this paper, we generalize this procession further by adding commutative grouplike elements b（ik）, c（ik）, g（ik）, h（ik）（i ∈I, k = 1,..., mi） of a Hopf algebra H to the quantized enveloping algebra Uq（G） of a Borcherds superalgebra G defined by a symmetrizable integral Borcherds–Cartan matrix A =（aij）i,j∈I. Therefore, we define an extended Hopf superalgebra HUq（G）. We also discuss the basis and the grouplike elements of HUqG.

关键词： Borcherds superalgebra Hopf algebra quantized enveloping algebra

On the Terai-Jésmanowicz Conjecture

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2008年第12期24卷 2061-2064页

作者： Jian ye xia Ping Zhi YUAN Department of Basic Science Guangdong University of Finance Guangzhou 510521 P. R. China School of Mathematics South China Normal University Guangzhou 510631 P. R. China

In this paper, we prove that if a, b and c are pairwise coprime positive integers such that a^2＋b^2=c^r,a〉b,a≡3 （mod4）,b≡2 （mod4） and c-1 is not a square, thena a^x＋b^y=c^z has only the positive integer solution （x, y, z） = （2, 2, r）. Let m and r be positive integers with 2｜m and 2 r, define the integers Ur, Vr by （m ＋√-1）^r=Vr＋Ur√-1. If a = ｜Ur｜,b=｜Vr｜,c = m^2＋1 with m ≡ 2 （mod 4）,a ≡ 3 （mod 4）, and if r 〈 m/√1.5log3（m^2＋1）-1, then a^x ＋ b^y = c^z has only the positive integer solution （x,y, z） = （2, 2, r）. The argument here is elementary.

关键词： exponential diophantine equations Terai-Jesmanowicz conjecture Lucas sequences

GLOBAL WELL-POSEDNESS FOR THE DENSITY-DEPENDENT INCOMPRESSIBLE MAGNETOHYDRODYNAMIC FLOWS IN BOUNDED DOMAINS

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Scientia 2018年第6期38卷 1833-1845页

作者： Defu CHEN xia ye. College of Mathematics and Information Science Jiangxi Normal University

In this paper, we study the three-dimensional incompressible magnetohydrody-namic equations in a smooth bounded domains, in which the viscosity of the fluid and themagnetic diffusivity are concerned with density. The existence of global strong solutions isestablished in vacuum cases, provided the assumption that （｜｜μ（ρ0）｜｜Lp＋｜｜ v（P0）｜｜Lq＋｜｜b0｜｜L^3 ＋｜｜ρO｜｜L^∞）（p,q〉3） is small enough, there is not any smallness condition on thevelocity.

关键词： incompressible MHD global solution small initial data

Two new species of Yushania(Poaceae:Bambusoideae)from South China,with a taxonomic revision of related species

在线全文

学校读者我要写书评

暂无评论

Plant Diversity 2021年第6期43卷 492-501页

作者： xia-Ying ye Yu-xiao Zhang De-Zhu Li Germplasm Bank of Wild Species Kunming Institute of BotanyChinese Academy of SciencesKunmingYunnan 650201China Agronomy and Life Science Department Zhaotong UniversityZhaotongYunnan 657000China Yunnan Academy of Biodiversity Southwest Forestry UniversityKunmingYunnan 650224China

Two new species of Yushania(Poaceae,Bambusoideae,Arundinarieae)are described and illustrated from Hunan,*** longshanensis ***&*** is distinguished from related species(***,*** and ***)by having a thinner culm(0.2e0.3 cm in diameter),glabrous sheath scar,no oral setae,a large glabrous leaf blade(10e200.9e1.3 cm)and 3e4 pairs of secondary *** stoloniforma ***&*** has a distinctive scrambling habit,which differs from its putative close *** of these two new species have a solitary branch at the basal nodes and can be assigned to Yushania *** based on morphological ***,we treated Yushania gigantea ***&*** as a new synonym of *** *** and renamed *** ***&*** as *** ***&***.

关键词： Arundinarieae Yushania Hunan New species Taxonomy