期刊文献+
共找到29篇文章
< 1 2 >
每页显示 20 50 100
应用优超理论推广单形Finsler-hadwiger型不等式
1
作者 朱杏华 《宁德师范学院学报(自然科学版)》 1999年第4期252-254,共3页
应用优超理论,在En 中n 维单形及其k(1 ≤k≤n - 1)维子单形体积、内径、外径、旁切超球半径之间给出Finsler- hadwiger 型不等式的几种推广形式.
关键词 子单形 内径 不等式
下载PDF
一个涉及四个单形的不等式
2
作者 田文平 苏化明 《大学数学》 1994年第S1期28-30,共3页
本文给出了四个单形的棱长与其k维子单形(k≥2)体积之间的一个关系式。
关键词 子单形 棱长 体积
下载PDF
也谈Finsler-Hadwiger和Neuberg-Pedoe不等式的高维推广和加强 被引量:2
3
作者 《湖南教育学院学报》 1998年第2期1-7,共7页
本文对欧氏空间En中的n维单形和它的k(l≤k≤n-1)维子单形,给出了著名的Finsler-Hadwiger不等式、Neuberg-Pedoe不等式、彭家贵不等式以及Euler不等式的高维推广和加强.
关键词 子单形 体积 不等式 F-H不等式 N-P不等式
下载PDF
Phylogenetic relationships of 18 passerines based on Adenylate Kinase Intron 5 sequences
4
作者 国会艳 于慧鑫 +1 位作者 白素英 马玉堃 《Journal of Forestry Research》 SCIE CAS CSCD 2008年第3期239-244,共6页
The 18 species of bird studied originally are known to belong to muscicapids, robins and sylviids of passerines, but some dis- putations are always present in their classification systems. In this experiment, phylogen... The 18 species of bird studied originally are known to belong to muscicapids, robins and sylviids of passerines, but some dis- putations are always present in their classification systems. In this experiment, phylogenetic relationships of 18 species of passerines were studied using Adenylate Kinase lntron 5 (AKS) sequences and DNA techniques. Through sequences analysis in comparison with each other, phylogenetic tree figures of 18 species of passerines were constructed using Neighbor-Joining (N J) and Maximum-Parsimony (MP) meth- ods . The results showed that sylviids should be listed as an independent family, while robins and flycatchers should be listed into Musci- capidae. Since the phylogenetic relationships between long-tailed tits and old world warblers are closer than that between long-tailed tits and parids, the long-tailed tits should be independent of paridae and be categorized into aegithalidae. Muscicapidae and Paridae are known to be two monophylitic families, but Sylviidae is not a monophyletic group. AK5 sequences had better efficacy in resolving close relationships of interspecies among intrageneric groups. 展开更多
关键词 molecular phylogeny Adenylate Kinase lntron 5 PASSERIFORMES MONOPHYLY
下载PDF
Construction of Deficient Strain by Selenomonas ruminantium Mutant with the Acetic Acid and Analysis on Its Related Enzyme Activity
5
作者 苑学 逄晓阳 +1 位作者 刘国文 王哲 《Agricultural Science & Technology》 CAS 2011年第8期1226-1229,共4页
[Objective]The research aimed to construct deficient strain generated by Selenomonas ruminantium mutant with the acetic acid and analyze its fermentation characteristics.[Method]Based on the transposon tagging method,... [Objective]The research aimed to construct deficient strain generated by Selenomonas ruminantium mutant with the acetic acid and analyze its fermentation characteristics.[Method]Based on the transposon tagging method,Selenomonas ruminantium(recipient strain)was carried out the transposon mutagenesis via the transposon donor strain E.coli S17-1/pZJ25∷Tn5.The zygote was screened by using the selective medium which included kanamycin and sodium fluoroacetate.[Result]Seven transposon engineered strains which had the stable resistance to kanamycin and fluoroethanoic acid were screened.Selenomonas ruminantium mutant was carried out 16S rRNA and Tn5 PCR identification.Moreover,the specific activities of AK and PTA were analyzed.The mutant belonged to fluoroethanoic acid resistance strain with pta gene deficiency.[Conclusion]The research laid the foundation for further studying the cellular metabolic network and regulation of acetic acid in rumen microorganism of ruminant animal. 展开更多
关键词 Selenomonas ruminantium TRANSPOSON PTA AK
下载PDF
Quantum Tunneling Radiation of Reissner-Nordstrom de Sitter Black Hole with a Global Monopole 被引量:2
6
作者 JIANG Qing-Quan YANG Shu-Zheng LI Hui-Ling 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第3期457-460,共4页
Applying Parikh's quantum tunneling model, we study the quantum tunneling radiation of Reissne- Nordstrom de Sitter black hole with a global monopole. The result shows that the tunneling rates at the event horizon an... Applying Parikh's quantum tunneling model, we study the quantum tunneling radiation of Reissne- Nordstrom de Sitter black hole with a global monopole. The result shows that the tunneling rates at the event horizon and the cosmic horizon are related to Bekenstein-Hawking entropy if we take the energy conservation into consideration, and the true radiate spectrum is not precisely thermal. 展开更多
关键词 Reissner-Nordstrom de Sitter black hole global monopole energy conservation tunneling rate
下载PDF
Scheme for Teleportation of a Multipartite Quantum State by Using a Single Entangled Pair as Quantum Channel 被引量:7
7
作者 WANG Xin-Wen WANG Zhi-Yong XIA Li-Xin 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第2期257-260,共4页
We present a theoretical scheme for perfect teleportation of an unknown multipartite two-level state by a single EPR (Einstein-Podolsky-Rosen) pair, and then generalize it to multilevel, i.e., an N-quNit state can b... We present a theoretical scheme for perfect teleportation of an unknown multipartite two-level state by a single EPR (Einstein-Podolsky-Rosen) pair, and then generalize it to multilevel, i.e., an N-quNit state can be teleported by a single quNit entangled pair, with additional local unitary operations. The feature of the scheme is that teleporting a multipartite state with a reduced amount of entanglement costs less classical bits. 展开更多
关键词 EPR pair quNit entangled pair N-qubit cat-like state N-quNit cat-like state TELEPORTATION
下载PDF
Probabilistic Teleportation of an Arbitrary Two-Atom State in Cavity QED 被引量:2
8
作者 LiU Jin-Ming 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第3期446-450,共5页
We propose a scheme for the teleportation of an arbitrary two-atom state by using two pairs of two-atom nonmaximally entangled states as the quantum channel in cavity QED. It is Shown that no matter whether the arbitr... We propose a scheme for the teleportation of an arbitrary two-atom state by using two pairs of two-atom nonmaximally entangled states as the quantum channel in cavity QED. It is Shown that no matter whether the arbitrary two-atom pure state to be teleported is entangled or not, our teleportation scheme can always be probabilistically realized. The success prohability of teleportation is determined by the smaller coemcients of the two initially entangled atom pairs. 展开更多
关键词 quantum teleportation arbitrary two-atom state cavity QED
下载PDF
History of study,updated checklist,distribution and key of scorpions (Arachnida:Scorpiones) from China 被引量:6
9
作者 Zhi-Yong DI Zi-Zhong YANG +2 位作者 Shi-Jin YIN Zhi-Jian CAO Wen-Xin LI 《Zoological Research》 CAS CSCD 北大核心 2014年第1期3-19,共17页
This review describes the history of taxonomic research on scorpions and provides an updated checklist and key of the scorpions currently known in China. This checklist is based on a thorough review of the extant lite... This review describes the history of taxonomic research on scorpions and provides an updated checklist and key of the scorpions currently known in China. This checklist is based on a thorough review of the extant literatures on scorpion species whose presence has been confirmed in China through field expeditions and examination of scorpion collections, excepting a few members that have no clear distribution or are currently in doubt. Totally, the scorpion fauna of China consists of 53 species and subspecies belonging to 12 genera crossing five families, with 33 species(62.3%) and one genus being recorded as endemic. Additionally, identification key and the distribution of scorpions from China are provided. 展开更多
关键词 Scorpion Taxonomy CHECKLIST KEY DISTRIBUTION China
下载PDF
Probabilistic Teleportation of an Unknown One-Particle State by a Three-Particle General W State 被引量:3
10
作者 XIU Xiao-Ming DONG Li GAO Ya-Jun 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第4期625-628,共4页
Two schemes for teleporting an unknown one-particle state are proposed when a general W state is utilized as quantum channel. In the first scheme, after the sender (Alice) makes a Bell-state measurement on her parti... Two schemes for teleporting an unknown one-particle state are proposed when a general W state is utilized as quantum channel. In the first scheme, after the sender (Alice) makes a Bell-state measurement on her particles, the recipient (Bob) performs a Von Neumann measurement and introduces an auxiliary particle, and carries out a unitary transformation on his particle and the auxiliary particle, and performs a Von Neumann measurement on the auxiliary particle to confirm whether the teleportation succeeds or not. In the second scheme, the recipient (Bob) does not need to perform the first Von Neumann measurement or introduce the auxiliary particle, which is necessary in the first scheme. It is shown that the maxima/probabilities of successful teleportation of the two schemes are identical if the recipient (Bob) performs an appropriate unitary transformation and adopts a proper particle on which he recovers the quantum information of state to be teleported. 展开更多
关键词 quantum information probabilistic teleportation ENTANGLEMENT general W state
下载PDF
Interface-Optical-Phonon Modes in Quasi-one-dimensional Wurtzite Rectangular Quantum Wires 被引量:1
11
作者 ZHANG Li 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第6X期1109-1112,共4页
By employing the dielectric continuum model and Loudon's uniaxial crystal model, the interface optical (IO) phonon modes in a freestanding quasi-one-dimensional (Q1D) wurtzite rectangular quantum wire are derived... By employing the dielectric continuum model and Loudon's uniaxial crystal model, the interface optical (IO) phonon modes in a freestanding quasi-one-dimensional (Q1D) wurtzite rectangular quantum wire are derived and analyzed. Numerical calculation on a freestanding wurtzite GaN quantum wire is performed. The resulte reveal that the dispersion frequencies of IO modes sensitively depend on the geometric structures of the Q1D wurtzite rectangular quantum wires, the free wave-number kz in z-direction and the dielectric constant of the nonpolar matrix. The degenerating behavior of the IO modes in Q1D wurtzite rectangular quantum wire has been clearly observed in the case of small wave-number kz and Iarge ratio of length to width of the rectangular crossing profile. The limited frequency behaviors of IO modes have been analyzed deeply, and detailed comparisons with those in wurtzite planar quantum wells and cylindrical quantum wires are also done. The present theories can be looked on as a generalization of that in isotropic rectangular quantum wires, and it can naturally reduce to the case of Q1D isotropic quantum wires once the anisotropy of the wurtzite material is ignored. 展开更多
关键词 interface phonon modes polarization eigenvectors rectangular quantum wire
下载PDF
Fast weighting method for plasma PIC simulation on GPU-accelerated heterogeneous systems 被引量:2
12
作者 杨灿群 吴强 +3 位作者 胡慧俐 石志才 陈娟 唐滔 《Journal of Central South University》 SCIE EI CAS 2013年第6期1527-1535,共9页
Particle-in-cell (PIC) method has got much benefits from GPU-accelerated heterogeneous systems.However,the performance of PIC is constrained by the interpolation operations in the weighting process on GPU (graphic pro... Particle-in-cell (PIC) method has got much benefits from GPU-accelerated heterogeneous systems.However,the performance of PIC is constrained by the interpolation operations in the weighting process on GPU (graphic processing unit).Aiming at this problem,a fast weighting method for PIC simulation on GPU-accelerated systems was proposed to avoid the atomic memory operations during the weighting process.The method was implemented by taking advantage of GPU's thread synchronization mechanism and dividing the problem space properly.Moreover,software managed shared memory on the GPU was employed to buffer the intermediate data.The experimental results show that the method achieves speedups up to 3.5 times compared to previous works,and runs 20.08 times faster on one NVIDIA Tesla M2090 GPU compared to a single core of Intel Xeon X5670 CPU. 展开更多
关键词 GPU computing heterogeneous computing plasma physics simulations particle-in-cell (PIC)
下载PDF
A novel particle swarm optimizer without velocity:Simplex-PSO 被引量:5
13
作者 肖宏峰 谭冠政 《Journal of Central South University》 SCIE EI CAS 2010年第2期349-356,共8页
A simplex particle swarm optimization(simplex-PSO) derived from the Nelder-Mead simplex method was proposed to optimize the high dimensionality functions.In simplex-PSO,the velocity term was abandoned and its referenc... A simplex particle swarm optimization(simplex-PSO) derived from the Nelder-Mead simplex method was proposed to optimize the high dimensionality functions.In simplex-PSO,the velocity term was abandoned and its reference objectives were the best particle and the centroid of all particles except the best particle.The convergence theorems of linear time-varying discrete system proved that simplex-PSO is of consistent asymptotic convergence.In order to reduce the probability of trapping into a local optimal value,an extremum mutation was introduced into simplex-PSO and simplex-PSO-t(simplex-PSO with turbulence) was devised.Several experiments were carried out to verify the validity of simplex-PSO and simplex-PSO-t,and the experimental results confirmed the conclusions:(1) simplex-PSO-t can optimize high-dimension functions with 200-dimensionality;(2) compared PSO with chaos PSO(CPSO),the best optimum index increases by a factor of 1×102-1×104. 展开更多
关键词 Nelder-Mead simplex method particle swarm optimizer high-dimension function optimization convergence analysis
下载PDF
Monophyly or polyphyly? Possible conflict between morphological and molecular interpretations of the wellknown genus Zoothamnium(Ciliophora,Peritrichia) 被引量:1
14
作者 李丽芳 马洪钢 AL-RASHEID Khaled A.S. 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2015年第2期490-499,共10页
In this paper, we explore possible conflict between morphological and molecular interpretations of phylogenetic relationships within the well-known peritrichous genus Zoothamnium. On the basis of morphological evidenc... In this paper, we explore possible conflict between morphological and molecular interpretations of phylogenetic relationships within the well-known peritrichous genus Zoothamnium. On the basis of morphological evidence, for a long time this genus has been believed to be a well-defined monophyletic taxon. Nonetheless, Zoothamnium exhibits higher genetic diversity than the gross morphology of its species. Here, we used all available genetic information for the small subunit of ribosomal RNA (SSU rRNA) and internal transcribed spacer region (ITS1-5.8S-ITS2) for this genus to reconstruct phylogenies for four datasets (SSU rRNA, ITS1, ITS2, and ITS1-5.8S-ITS2) and a combined dataset (SSU rRNA+ITSI-5.8S- ITS2) using different phylogenetic methods and with consideration of the secondary structure of the genes. Confidence in phylogenetic tree selection was assessed with the approximately unbiased test. The molecular results showed both that Zoothamnium is more likely to be polyphyletic, and morphologically similar genera Zoothamnopsis and Myoschiston were always nested among Zoothamnium species. Accordingly, as with some other groups of ciliates, to understand more fully the correct phylogeny of Zoothamnium there remains a need for additional data from both morphological and molecular studies, covering additional Zoothamnium spp. and members of closely related genera (e.g. Zoothamnopsis, Myoschiston, and Epistylis). 展开更多
关键词 peritrichous ciliates Zoothamnium phylogenetic analyses MONOPHYLY POLYPHYLY
下载PDF
Teleportation of Bipartite Entangled State Without Joint Measurement
15
作者 ZHOU Jian YANG Ming CAO Zhuo-Liang 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第4期633-635,共3页
In this paper, we present a probabilistic teleportation scheme for unknown bipartite entangled state. By using linear optical elements, we convert the Bell-state measurement into separated single-qubit measurements.
关键词 TELEPORTATION single-qubit measurement linear optical element
下载PDF
Prediction of pyrolysis kinetic parameters from biomass constituents based on simplex-lattice mixture design 被引量:1
16
作者 Panusit Sungsuk Sasiporn Chayaporn +3 位作者 Sasithorn Sunphorka Prapan Kuchonthara Pornpote Piumsomboon Benjapon Chalermsinsuwan 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2016年第4期535-542,共8页
The aim of this study is to determine the effect of the main chemical components ofbiomass: cellulose, hemicel- lulose and lignin, on chemical kinetics ofbiomass pyrolysis. The experiments were designed based on a si... The aim of this study is to determine the effect of the main chemical components ofbiomass: cellulose, hemicel- lulose and lignin, on chemical kinetics ofbiomass pyrolysis. The experiments were designed based on a simplex- lattice mixture design. The pyrolysis was observed by using a thermogravimetric analyzer. The curves obtained from the employed analytical method fit the experimental data (R2 〉 0.9). This indicated that this method has the potential to determine the kinetic parameters such as the activation energy (E~), frequency factor (A) and re- action order (n) for each point of the experimental design. The results obtained from the simplex-lattice mixture design indicated that cellulose had a significant effect on Ea and A, and the interaction between cellulose and lignin had an important effect on the reaction order, n. The proposed models were then proved to be useful for predicting pyrolysis behavior in real biomass and so could be used as a simple approximation for predicting the overall trend of chemical reaction kinetics. 展开更多
关键词 BiomassPyrolysisSimplex-lattice mixture designKineticsModeling
下载PDF
Effect of loading rates on crack propagating speed,fracture toughness and energy release rate using single-cleavage trapezoidal open specimen under impact loads 被引量:4
17
作者 LANG Lin ZHU Zhe-ming +3 位作者 WANG Han-bing HUANG Jian-wei WANG Meng ZHANG Xian-shang 《Journal of Central South University》 SCIE EI CAS CSCD 2020年第8期2440-2454,共15页
The former studies indicate that loading rates significantly affect dynamic behavior of brittle materials,for instance,the dynamic compressive and tensile strength increase with loading rates.However,there still are m... The former studies indicate that loading rates significantly affect dynamic behavior of brittle materials,for instance,the dynamic compressive and tensile strength increase with loading rates.However,there still are many unknown or partially unknown aspects.For example,whether loading rates have effect on crack dynamic propagating behavior(propagation toughness,velocity and arrest,etc).To further explore the effect of loading rates on crack dynamic responses,a large-size single-cleavage trapezoidal open(SCTO)specimen was proposed,and impacting tests using the SCTO specimen under drop plate impact were conducted.Crack propagation gauges(CPGs)were employed in measuring impact loads,crack propagation time and velocities.In order to verify the testing result,the corresponding numerical model was established using explicit dynamic software AUTODYN,and the simulation result is basically consistent with the experimental results.The ABAQUS software was used to calculate the dynamic SIFs.The universal function was calculated by fractal method.The experimental-numerical method was employed in determining initiation toughness and propagation toughness.The results indicate that crack propagating velocities,dynamic fracture toughness and energy release rates increase with loading rates;crack delayed initiation time decreases with loading rates. 展开更多
关键词 crack velocity dynamic fracture toughness particle velocity loading rate single-cleavage trapezoidal open(SCTO)specimen
下载PDF
Reflecting and transmitting effect of a planar unidirectionally conducting screen
18
作者 鄂鹏 江滨浩 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2009年第2期242-246,共5页
The reflecting and transmitting effects of a planar unidirectionally conducting screen are analyzed based on the accurate closed-form expression for electric field of an arbitrarily oriented electric dipole.For a dipo... The reflecting and transmitting effects of a planar unidirectionally conducting screen are analyzed based on the accurate closed-form expression for electric field of an arbitrarily oriented electric dipole.For a dipole oriented along the wire elements of the screen,the screen acts as a perfectly electrically conducting plane.For a dipole perpendicular to the wire elements,the fields reflected by the screen can be interpreted as the contribution of an image dipole and image transmission-line current source,while the transmitted field is arisen from image transmission-line source.The expressions of related surface waves are derived and can be compared with previous results. 展开更多
关键词 electromagnetic fields unidirectionally conducting screen reflection and transmission electric dipole
下载PDF
Critical Properties of Mixed Ising Spin System with Different Trimodal Transverse Fields in the Presence of Single-Ion Anisotropy
19
作者 CHEN Qiang YAN Shi-Lei 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第6期1131-1136,共6页
Within the framework of an effective field approximation, the effects of single-ion anisotropy and different trimodal transverse fields of two sublattices on the critical properties of the mixed spin-1/2 and spin-1 Is... Within the framework of an effective field approximation, the effects of single-ion anisotropy and different trimodal transverse fields of two sublattices on the critical properties of the mixed spin-1/2 and spin-1 Ising system are investigated on the simple cubic lattice. A smaller single-lon anisotropy can magnify magnetic ordering phases and a larger one can depress magnetic ordering phase for T-Ω1/2 space at low temperatures, while a smaller single-ion anisotropy can hardly change the value of critical transverse field for T-Ω1 space. On the other hand, influences of two different trimodal transverse fields concentrations on tricritical points and magnetic ordering phases take on some interesting results in T-D space. The main reason comes from the common action of single-ion anisotropy, different transverse fields and two trimodal distributions. 展开更多
关键词 critical property mixed spin system trimodal transverse field single-ion anisotropy
下载PDF
Photoionization Cross Section and Resonance Structure of Mn+
20
作者 LU Peng-Fei LIU Jin-Chao YANG Xiang-Dong 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第5期911-913,共3页
A photoionization cross section calculation ofMn^+ is performed in the formalism of many-body perturbation theory for photon energies ranging from 48 eV to 56 eV. We consider excitations from the 3p, 3d, and 4s subsh... A photoionization cross section calculation ofMn^+ is performed in the formalism of many-body perturbation theory for photon energies ranging from 48 eV to 56 eV. We consider excitations from the 3p, 3d, and 4s subshells. The effects of the strong 3p→ 3d and 3p→ 4s transitions are included as resonant contributions to the total cross sections. Good agreement with experiment is found. 展开更多
关键词 many-body perturbation theory effective single-particle potential generalized resonance method
下载PDF
上一页 1 2 下一页 到第
使用帮助 返回顶部