期刊文献+
共找到29篇文章
< 1 2 >
每页显示 20 50 100
外磁场作用下液晶中向列序的计算 被引量:1
1
作者 张志东 邵喜斌 黄锡珉 《计算物理》 CSCD 北大核心 1997年第4期448-449,441,共3页
在格胞理论的基础上计算外磁场作用下液晶中的向列序。考虑分子短程关联后,序参数和内能对磁场强度的依赖关系与计算机模拟结果较好地符合。克服了平均场理论遇到的困难。
关键词 液晶 外磁场 向列序 短程关联 格胞理论
下载PDF
基于向列相液晶形变研究空间各向异性两体势 被引量:1
2
作者 张艳君 张志东 +1 位作者 崔建坡 魏怀鹏 《液晶与显示》 CAS CSCD 北大核心 2006年第3期201-205,共5页
基于分子两体势研究向列相液晶的形变。该两体势是空间各向异性的并且依赖于液晶的弹性常数。理论处理中假定具有理想向列序,这意味着分子长轴取向方向与液晶指向矢是重合的,而总自由能等于总相互作用能。通过解析形式研究3种基本的弗... 基于分子两体势研究向列相液晶的形变。该两体势是空间各向异性的并且依赖于液晶的弹性常数。理论处理中假定具有理想向列序,这意味着分子长轴取向方向与液晶指向矢是重合的,而总自由能等于总相互作用能。通过解析形式研究3种基本的弗雷德里克兹转变,得到了势参数与弹性常数的又一关系。通过MonteCarlo模拟方法研究了新两体作用势所描写向列相的热力学性质。 展开更多
关键词 液晶形变 空间各向异性两体势 理想向列序 弗雷德里克兹转变 MONTE Carlo 模拟
下载PDF
基于修正的Gruhn-Hess两体势模型研究弯曲形变向列相液晶盒 被引量:1
3
作者 周璇 张志东 《计算物理》 EI CSCD 北大核心 2010年第4期598-602,共5页
使用修正的Gruhn-Hess空间各向异性两体势模型研究弯曲形变向列相液晶盒.为了易与弹性理论的结果进行比较,做单一弹性常数近似.在理想有序条件下,对模型进行连续化处理,截断到形变的二阶项,给出的自由能密度公式与含k13项的弹性理论公... 使用修正的Gruhn-Hess空间各向异性两体势模型研究弯曲形变向列相液晶盒.为了易与弹性理论的结果进行比较,做单一弹性常数近似.在理想有序条件下,对模型进行连续化处理,截断到形变的二阶项,给出的自由能密度公式与含k13项的弹性理论公式一致.使用模型直接研究强锚泊弯曲形变向列相盒,没有出现弹性理论给出的边界处不连续.通过Monte Carlo模拟研究发现,两体势中的k13项将加剧弯曲盒中间层的涨落. 展开更多
关键词 Gruhn-Hess两体势 向列序 表面弹性项k13 内禀锚定 MONTE CARLO模拟
下载PDF
Isolation of the Flanking Sequences Adjacent to Transgenic T-DNA in Brassica napus Genome by an Improved Inverse PCR Method 被引量:2
4
作者 杨坤 吴学龙 +1 位作者 朗春秀 陈锦清 《Agricultural Science & Technology》 CAS 2010年第2期65-68,139,共5页
[Objective] The research aimed to isolate flanking sequences adjacent to the transgenic T-DNA in Brassica napus by an improved inverse PCR method.[Method] Using single clone of transgenic FS4 in Brassica napus as the ... [Objective] The research aimed to isolate flanking sequences adjacent to the transgenic T-DNA in Brassica napus by an improved inverse PCR method.[Method] Using single clone of transgenic FS4 in Brassica napus as the research materials,total DNA was extracted from transgenic Brassica napus by using modified CTAB method.After enzyme digestion and purification,self-joining was made.Two circles of nested PCR and the sequence alignment were carried out.[Result] A fragement with the size of 4.0 kb was amplified ... 展开更多
关键词 Inverse PCR(IPCR) Flanking sequences Improved CTAB method Transgenic Brassica napus
下载PDF
空间各向异性色散两体势向列相液晶形变研究
5
作者 王英涛 张艳君 +1 位作者 吴建海 张志东 《现代显示》 2009年第10期49-52,共4页
基于空间各向异性色散力势能,用简单的立方格子模型研究具有n层液晶分子所组成的向列相液晶形变。理论处理中假定具有理想向列序,这意味着分子长轴取向方向与液晶指向矢是一致的,而总自由能等于相互作用能。文中以解析形式研究了三种基... 基于空间各向异性色散力势能,用简单的立方格子模型研究具有n层液晶分子所组成的向列相液晶形变。理论处理中假定具有理想向列序,这意味着分子长轴取向方向与液晶指向矢是一致的,而总自由能等于相互作用能。文中以解析形式研究了三种基本的Fredericksz转变,给出了三个弹性常数,在近似下它们是相同的,且与连续体理论比较可以得到k13。 展开更多
关键词 色散力 空间各向异性两体势 理想向列序 Fredericksz转变 液晶形变
下载PDF
Micro-heterogeneity of Storage Glutelin in Rice Seed 被引量:4
6
作者 曲乐庆 魏晓丽 +3 位作者 佐藤光 小川雅广 熊丸敏博 贾旭 《Acta Botanica Sinica》 CSCD 2001年第8期815-820,共6页
The storage glutelin in rice ( Oryza sativa L.) seeds could be separated at least into more than 13 acidic and 19 basic polypeptides by two dimensional electrophoresis. Rice glutelin might be mainly controlled by abou... The storage glutelin in rice ( Oryza sativa L.) seeds could be separated at least into more than 13 acidic and 19 basic polypeptides by two dimensional electrophoresis. Rice glutelin might be mainly controlled by about six major genes according to the expression of glutelin polypeptides. The acidic polypeptide of glutelin could be clearly separated into two groups by peptide mapping and N-terminal amino acid sequence analysis. These two groups were just in accord with the GluA and GluB subfamilies exactly. 展开更多
关键词 rice glutelin two-dimensional electrophoresis N-terminal amino acid sequence
下载PDF
On the construction of cryptographically strong Boolean functions with desirable trade-off 被引量:1
7
作者 REN Kui PARK Jaemin KIM Kwangjo 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2005年第5期358-364,共7页
This paper proposes a practical algorithm for systematically generating strong Boolean functions (f:GF(2) n →GF(2)) with cryptographic meaning. This algorithm takes bent function as input and directly outputs the res... This paper proposes a practical algorithm for systematically generating strong Boolean functions (f:GF(2) n →GF(2)) with cryptographic meaning. This algorithm takes bent function as input and directly outputs the resulted Boolean function in terms of truth table sequence. This algorithm was used to develop two classes of balanced Boolean functions, one of which has very good cryptographic properties:nl(f)=2 2k?1?2k+2k?2 (n=2k), with the sum-of-squares avalanche characteristic off satisfying σf=24k+23k+2+23k-2 and the absolute avalanche characteristic off satisfying σf=24k+23k+2+23k-2. This is the best result up to now compared to existing ones. Instead of bent sequences, starting from random Boolean functions was also tested in the algorithm. Experimental results showed that starting from bent sequences is highly superior to starting from random Boolean functions. Key words Boolean functions - Bent sequences - Nonlinearity - GAC - PC - Balancedness Document code A CLC number TP301.6 展开更多
关键词 Boolean functions Bent sequences NONLINEARITY GAC PC BALANCEDNESS
下载PDF
Equation oriented method for Rectisol wash modeling and analysis 被引量:3
8
作者 高宁 翟持 +1 位作者 孙巍 张新宇 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2015年第9期1530-1535,共6页
Rectisol process is more efficient in comparison with other physical or chemical absorption methods for gas purification. To implement a real time simulation of Rectisol process, thermodynamic model and simulation str... Rectisol process is more efficient in comparison with other physical or chemical absorption methods for gas purification. To implement a real time simulation of Rectisol process, thermodynamic model and simulation strategy are needed. In this paper, a method of modified statistical associated fluid theory with perturbation theory is used to predict thermodynamic behavior of process. As Rectisol process is a highly heat-integrated process with many loops, a method of equation oriented strategy, sequential quadratic programming, is used as the solver and the process converges perfectly. Then analyses are conducted with this simulator. 展开更多
关键词 Rectisol process simulation Modified statistical associated fluid theory Equation oriented Sequential quadratic programming
下载PDF
Heat center of the western Pacific warm pool 被引量:4
9
作者 HU Shijian Hu Dunxin 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2012年第1期169-176,共8页
A heat center (HC) of the western Pacific warm pool (WPWP) is defined, its variability is examined, and a possible mechanism is discussed. Analysis and calculation of a temperature dataset from 1945-2006 show that... A heat center (HC) of the western Pacific warm pool (WPWP) is defined, its variability is examined, and a possible mechanism is discussed. Analysis and calculation of a temperature dataset from 1945-2006 show that the mean position of the HC during this period was near 0.4°S/169.0°E, at 38.0 m depth. From a time series of the HC, remarkable seasonal variability was found, mainly in the meridional and vertical directions. Interannual variabilities were dominant in the zonal and vertical directions. In addition, semiannual variation in the HC depth was discovered. The longitude of the HC varies with ENSO events, and its latitude is weakly related to ENSO on time scales shorter than a decade. The variation of the HC longitude leads the Nifio-3 index by about 3-4 months, and its depth lags the index for approximately 3 months. It is concluded that the HC depth results from a combination of its longitudinal and latitudinal variations. Low-pass-filtered time series reveal that the HC has moved eastward since the mid 1980s. 展开更多
关键词 western Pacific warm pool heat center VARIABILITY
下载PDF
Chromosomal localization of a tandemly repeated DNA sequence in Trifolium repens L
10
作者 ZHU JM NW ELLISON +1 位作者 RE ROWLAND (The Horticulture and Food Research Institute of NewZealand, M Albert Research Centre, Private Bag 92169, Auckland, New Zealand.)(New Zcaland Pastoral Agriculture Research Institute, Grasslands Research Centre, Private Bag 11 《Cell Research》 SCIE CAS CSCD 1996年第1期39-46,共8页
A karyotype of Trifolium repens constructed from mitotic cells revealed 13 pairs of metacentric and 3 pairs of submetacentric chromosomes including a pair of satellites located at the end of the short arm of chromosom... A karyotype of Trifolium repens constructed from mitotic cells revealed 13 pairs of metacentric and 3 pairs of submetacentric chromosomes including a pair of satellites located at the end of the short arm of chromosome 16.C-bands were identified around the centromeric regions of 8 pairs of chromosomes. A 350 bp tandemly repeated DNA sequence from T. repens labelled with digoxygenin hybridized to the proximal centromeric regions of 12 chromosome pairs. Some correlation between the distribution of the repeat sequence and the distribution of C-banding was demonstrated. 展开更多
关键词 Tandem repeat in situ hybridization digoxygenin-labelled probe C-BANDING KARYOTYPE
下载PDF
Increment of hFIX expression with endogenous intron 1 in vitro
11
作者 ZHENG BING XIAO YUN QIU +4 位作者 MIN TAN YONG NA XING DARU LU JING LUN XUE XIN FANG QIU(Institute of Genetics, Fudan Univerisity, Shanghai 200433) 《Cell Research》 SCIE CAS CSCD 1997年第1期21-29,共9页
This paper probes into the feasibility of increasing expression level of hFIX gene with endogenous nitron 1 sequence. hFIX minigene was obtained with middle sequence truncated nitron 1 inserted into the relative site ... This paper probes into the feasibility of increasing expression level of hFIX gene with endogenous nitron 1 sequence. hFIX minigene was obtained with middle sequence truncated nitron 1 inserted into the relative site of hFIX cDNA, and plasmid vector pKG5i’IX, retroviral vector GINaCi’IX were constructed. These vectors were transduced into target cells of PA317, C2C12, primary rabbit skin fibroblasts (RSF) and primary human skin fibroblasts (HSF). The expression level of mixed colonies are PA317/pKG5i’IX, 151 "g/106 cells/24h; PA317/GINaCi’IX, 308ng/106 cells/24 h; C2C12/G1 NaCi’IX, 186 ng/106 cells/24 h; RSF/GINaCi’IX, 1929 ng/106 cells/24 h; HSF/GlNaCi’IX, 1646 ng/106 cells/ 24 h. These results indicated that hFIX minigene with nitron 1 is able to increase the expression level to about 3 times of that of hFIX cDNA. Meanwhile, in order to study the application of hFIX minigene in the retroviral-mediated gene transfer system and refrain from nitron splicing during viral production, a retroviral vector GlNaCi’IXR with reversely inserted hFIX minigene expression cassette was constructed. The expression level of reverse constructor in PA317 cells was 390 ng/106 cells/24 h with 79% of bioactivity. PCR detection of HT/GlNaCi’IXR cells infected with PA317/ClNaCi’IXR supernatant confirmed the existence of nitron 1 sequence. These results suggested that expression vector with forward-inserted intronl-carrying hFIX expression cassette can be used in directed gene Human factor IX expression with nitron transfer, but when using the retroviral-mediated gene transfer system, reversely-inserted intronl-carrying hFIX expression cassette should be considered. 展开更多
关键词 Intron 1 human clotting factor IX (hFIX) gene transfer gene expression reverse inserted sequence
下载PDF
Wavelet matrix transform for time-series similarity measurement 被引量:2
12
作者 胡志坤 徐飞 +1 位作者 桂卫华 阳春华 《Journal of Central South University》 SCIE EI CAS 2009年第5期802-806,共5页
A time-series similarity measurement method based on wavelet and matrix transform was proposed,and its anti-noise ability,sensitivity and accuracy were discussed. The time-series sequences were compressed into wavelet... A time-series similarity measurement method based on wavelet and matrix transform was proposed,and its anti-noise ability,sensitivity and accuracy were discussed. The time-series sequences were compressed into wavelet subspace,and sample feature vector and orthogonal basics of sample time-series sequences were obtained by K-L transform. Then the inner product transform was carried out to project analyzed time-series sequence into orthogonal basics to gain analyzed feature vectors. The similarity was calculated between sample feature vector and analyzed feature vector by the Euclid distance. Taking fault wave of power electronic devices for example,the experimental results show that the proposed method has low dimension of feature vector,the anti-noise ability of proposed method is 30 times as large as that of plain wavelet method,the sensitivity of proposed method is 1/3 as large as that of plain wavelet method,and the accuracy of proposed method is higher than that of the wavelet singular value decomposition method. The proposed method can be applied in similarity matching and indexing for lager time series databases. 展开更多
关键词 wavelet transform singular value decomposition inner product transform time-series similarity
下载PDF
SELECTION OF THE LINEAR COMBINING VECTOR G OF THE GENERALIZED SELF-SHRINKING GENERATORS
13
作者 Dong Lihua Zeng Yong Hu Yupu 《Journal of Electronics(China)》 2006年第4期506-509,共4页
Given an m-sequence, the main factor influencing the least period of the Generalized Self-Shrinking (GSS) sequence is the selection of the linear combining vector G. Based on the calculation of the minimal polynomia... Given an m-sequence, the main factor influencing the least period of the Generalized Self-Shrinking (GSS) sequence is the selection of the linear combining vector G. Based on the calculation of the minimal polynomial ofL GSS sequences and the comparison of their degrees, an algorithm for selecting the linear combining vector G is presented, which is simple to understand, to implement and to prove. By using this method, much more than 2^L-l linear combining vectors G of the desired properties will be resulted. Thus in the practical application the linear combining vector G can be chosen with great arbitrariness. Additionally, this algorithm can be extended to any finite field easily. 展开更多
关键词 CRYPTOGRAPHY Stream cipher M-SEQUENCE Generalized Self-Shrinking (GSS) sequences
下载PDF
A Shear-wave Splitting Study of the Yingjiang M_S6.1 Earthquake Sequence Occurring on May 30,2014
14
作者 Li Jin Gao Yuan +3 位作者 Xu Fukun Xiang Yang Xiang Yuan Liu Geng 《Earthquake Research in China》 CSCD 2016年第2期177-185,共9页
Earthquakes of M_S5. 6 and M_S6.1 occurred in Yingjiang,Yunnan on May 24 and May 30,2014 respectively. In this paper,we use the waveform data recorded by mobile seismic stations( KAC) which were set up in the source a... Earthquakes of M_S5. 6 and M_S6.1 occurred in Yingjiang,Yunnan on May 24 and May 30,2014 respectively. In this paper,we use the waveform data recorded by mobile seismic stations( KAC) which were set up in the source area after the Yingjiang MS5. 6earthquake on May 24,2014 to study the shear-wave splitting characteristics of Yingjiang M_S6.1 earthquake sequence with the SAM method. The result shows that predominant polarization of fast shear-waves before the M_S6.1 earthquake is consistent with the direction of regional principal compressive stress,and predominant polarization of fast shear-waves before the M_S6.1 earthquake show better consistency and smaller dispersion compared to after the M_S6.1 earthquake,and there may be a deflection for the fast shearwaves predominant polarization between the M_S6.1 earthquake sequence and foreshock sequence. We found that the time-delays generally exhibited a lower level before the M_S6.1earthquake and a relatively higher value after the M_S6.1 earthquake. 展开更多
关键词 Yingjiang earthquake sequence Foreshock Shear-wave splittingPolarization of fast shear-waves Time-delays
下载PDF
Pattern recognition and prediction study of rock burst based on neural network 被引量:2
15
作者 LI Hong 《Journal of Coal Science & Engineering(China)》 2010年第4期347-351,共5页
Many monitoring measures were used in the production field for predicting rockburst.However, predicting rock burst according to complicated observation data is alwaysa pressing problem in this research field.Though th... Many monitoring measures were used in the production field for predicting rockburst.However, predicting rock burst according to complicated observation data is alwaysa pressing problem in this research field.Though the critical value method gets extensiveapplication in practice, it stresses only on the superficial change of data and overlooks alot of features of rock burst and useful information that is concealed and hidden in the observationtime series.Pattern recognition extracts the feature value of time domain, frequencydomain and wavelet domain in observation time series to form Multi-Feature vectors,using Euclidean distance measure as the separable criterion between the same typeand different type to compress and transform feature vectors.It applies neural network asa tool to recognize the danger of rock burst, and uses feature vectors being compressedto carry out training and studying.It is proved by test samples that predicting precisionshould be prior to such traditional predicting methods as pattern recognition and critical indicatormethod. 展开更多
关键词 rock burst multi-feature pattern recognition neural network
下载PDF
SUBSET PARALLEL VOLTERRA FILTER FOR NARROWBAND INTERFERENCE SUPPRESSION IN DSSS COMMUNICATIONS
16
作者 Ma Wenqiang Chen Hao 《Journal of Electronics(China)》 2006年第4期606-609,共4页
Subset Parallel Adaptive Volterra Filter (SPAVF) design algorithm is proposed in this letter. Contri-bution factor is introduced in SPAVF, and it can get rid of redundant elements efficiently in the extended input vec... Subset Parallel Adaptive Volterra Filter (SPAVF) design algorithm is proposed in this letter. Contri-bution factor is introduced in SPAVF, and it can get rid of redundant elements efficiently in the extended input vector. Computational weight can be reduced largely, and BER performance of SPAVF can be improved by getting rid of the influence of redundant elements in the input vector. Simulation result proves its advantage compared to AVF and PSVF. 展开更多
关键词 Volterra filter Direct Sequence Spectrum Spreading(DSSS) Interference suppression Subset vector
下载PDF
Bi-directional Secure Communication Based on Discrete Chaotic Synchronization
17
作者 LONG Min QIU Shui-Sheng PENG Fei 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第6期1076-1080,共5页
Discrete chaotic systems are used for bi-directlonal secure communication. Both sides of communication keep sending signals to achieve their synchronization, and then recover the messages. However, the third side with... Discrete chaotic systems are used for bi-directlonal secure communication. Both sides of communication keep sending signals to achieve their synchronization, and then recover the messages. However, the third side without keys cannot get useful information. Known-plaintext attack is also engaged to analyze this method, and the simulation results show that the proposed method can reach high security performance. 展开更多
关键词 bi-directional secure communication discrete chaotic synchronization
下载PDF
Phase Diagram of XY Model with Nematic Coupling on the Simple Cubic Lattice
18
作者 吕建平 陈庆虎 《Communications in Theoretical Physics》 SCIE CAS CSCD 2012年第1期166-168,共3页
Using cluster Monte Carlo method, we numerically investigate the coupling on the simple cubic lattice. We determine critical lines belong to the criticality in the XY model with nematic three-dimensional XY universali... Using cluster Monte Carlo method, we numerically investigate the coupling on the simple cubic lattice. We determine critical lines belong to the criticality in the XY model with nematic three-dimensional XY universality class in variable of θ (2θ) between the XY-ferromagnetic (nematic) and disordered states. Fhrthermore, the phase transition between the XY-ferromagnetic and the nematie states is found to be in the three-dimensional Ising universality class. The critical points are determined from the intersections of Binder ratios for various system sizes. With two sets of critical points obtained, we finally construct the phase diagram on the A-J plane. 展开更多
关键词 nematic phase phase diagram scaling analysis
下载PDF
Parameter selection in time series prediction based on nu-support vector regression
19
作者 胡亮 Che Xilong 《High Technology Letters》 EI CAS 2009年第4期337-342,共6页
The theory of nu-support vector regression (Nu-SVR) is employed in modeling time series variationfor prediction. In order to avoid prediction performance degradation caused by improper parameters, themethod of paralle... The theory of nu-support vector regression (Nu-SVR) is employed in modeling time series variationfor prediction. In order to avoid prediction performance degradation caused by improper parameters, themethod of parallel multidimensional step search (PMSS) is proposed for users to select best parameters intraining support vector machine to get a prediction model. A series of tests are performed to evaluate themodeling mechanism and prediction results indicate that Nu-SVR models can reflect the variation tendencyof time series with low prediction error on both familiar and unfamiliar data. Statistical analysis is alsoemployed to verify the optimization performance of PMSS algorithm and comparative results indicate thattraining error can take the minimum over the interval around planar data point corresponding to selectedparameters. Moreover, the introduction of parallelization can remarkably speed up the optimizing procedure. 展开更多
关键词 parameter selection time series prediction nu-support vector regression (Nu-SVR) parallel multidimensional step search (PMSS)
下载PDF
Work Organization at Farm Level: A Process-Led Approach to Understand Land Use Changes
20
作者 S. Madelrieux L. Dobremez B. Dedieu 《Journal of Agricultural Science and Technology》 2010年第4期57-66,共10页
In the French Alps, some grasslands have been abandoned, others are invaded by scrub whereas they are still used by farmers What are the relationships between land use changes and other changes at farm level that lead... In the French Alps, some grasslands have been abandoned, others are invaded by scrub whereas they are still used by farmers What are the relationships between land use changes and other changes at farm level that lead to scrub invasion? We hypothesize that they are linked by two work organization processes: process of changes (changes in the household and farm) leading to less intensive land use; and annual processes (sequences of activities during the year) and their repetition from one year to another, leading to insufficient land maintenance. In this paper, we present a study carried out in the Northern French Alps, based on surveys with livestock farmers. It appears that land use changes are often the consequence of other changes made to address work problems, and land use sequences are defined according to workforce and prioritization of tasks. This highlights the importance of considering farmers as workers in order to evaluate land use changes at the farm level and to link them to the human dimension within farming systems. 展开更多
关键词 Land use farm process work organization
下载PDF
上一页 1 2 下一页 到第
使用帮助 返回顶部