检索结果-南通市图书馆

Global instability of Stokes layer for whole wave numbers

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2016年第8期37卷 999-1012页

作者： Wei kong Jisheng LUO Department of Mechanics Tianjin University

The study on the global instability of a Stokes layer, which is a typical unsteady flow, is usually a paradigm for understanding the instability and transition of unsteady flows. Previous studies suggest that the neutral curve of the global instability obtained by the Floquet theory is only mapped out in a limited range of wave numbers （0.2 ≤ a ≤ 0.5）. In this paper, the global instability is investigated with numerical simulations for all wave numbers. It is revealed that the peak of the disturbances displays irregularity rather than the periodic evolution while the wave number is beyond the above range. A ＂neutral point＂ is redefined, and a neutral curve of the global instability is presented for the whole wave numbers with this new definition. This work provides a deeper understanding of the global instability of unsteady flows.

关键词： Stokes layer instantaneous instability Floquet theory neutral curve

On the Integrality of Characteristic Elements in Nonabelian Iwasawa Theory

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1期24卷 43-58页

作者： Ling Quan kong School of Mathematical Sciences Beijing Normal University Beijing 100875 P. R. China

This paper is concerned with a conjecture formulated by Coates et al in [4] which describes the relation between the integrality of the characteristic elements and their evaluations in the noncommutative Iwasawa theor... 详细信息

关键词： p-adic Lie group K group characteristic element Iwasawa theory

Development and experience in the monitoring,assessment and control of environmentalpollutants in Hong kong

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 1991年第2期3卷 1-10页

作者： Feng Yingsheng(Y.S.Fung)Deparnent of Chemistry,University of Hong kong,Hong kong

The late start of environmental protection in Hong kong was discussed in the light of problems encountered during the development of environmental protection legislation in Hong kong for the past 20 years. The collaboration in monitoring and assessment of environmental pollutants between the University of Hong kong and various governments were descrbed in parallel with the progress in environmental protection in Hong kong. The developments of new analytical techniques for environmental monitoring and analysis is given and their application in environmental control described. The joint projects in assessment and control of environmental pollutants carried out in collaboration with local industries and other organizations within and without the university are given and discussed. The problems and possible solution facing Hong kong in development control equipment for small scale industries are discussed and areas of development identified. The development and experience in the monitoring assessment and control of environmental pollutants in Hong kong are summarized and areas of difficulties are illustrated.

关键词： monitoring of pollutants assessment of pollutants control of pollutants small scale industries urban pollution.

Complexation with pre-formed“empty”V-type starch for encapsulation of aroma compounds

在线全文

学校读者我要写书评

暂无评论

Food Science and Human Wellness 2023年第2期12卷 488-494页

作者： Jingyi Zhou Lingyan kong Department of Human Nutrition and Hospitality Management The University of AlabamaTuscaloosa35487USA

Aroma compounds are low-molecular-weight organic volatile molecules and are broadly utilized in the food ***,due to their high volatility and evaporative losses during processing and storage,the stabilization of these volatile ingredients using encapsulation is a commonly investigated *** of aroma compounds using starch inclusion complex could be a potential approach due to the hydrophobicity of the left-handed single helical *** the present study,we used starch of three different V-type structures,namely V,V,and V,to encapsulate six different aroma compounds,including1-decanol(DN),cis-3-hexen-1-ol(HN),4-allylanisole(AN),γ-decalactone(DA),trans-cinnamaldehyde(CA),and citral(CT).The formed inclusion complexes samples were characterized using complementary techniques,including X-ray diffraction(XRD)and differential scanning calorimetry(DSC).The results showed that upon complexation with aroma compounds,all V-subtypes retained their original crystalline ***,different trends of crystallinity were observed for each type of the prepared inclusion ***,among three V-type starches,V-type starch formed inclusion complexes with aroma compounds most efficiently and promoted the formation of FormⅡ*** study suggested that the structure of aroma compounds and the type of V starch could both affect the complexation properties.

关键词： Starch “Empty”V-type Aroma Inclusion complex Encapsulation

Ruling out small stopping sets and small girth in Tanner graph of QC-LDPC code

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2010年第1期21卷 134-137页

作者： Lingjun kong Yang Xiao Institute of Information Science Beijing Jiaotong University Beijing 100044 E R. China

The existing constructions of quasi-cyclic low-density parity-check （QC-LDPC） codes do not consider the problems of small stopping sets and small girth together in the Tanner graph, while their existences will lead to the bit error rate （BER） performance of QC-LDPC codes being much poorer than that of randomly constructed LDPC codes even decoding failure. To solve the problem, some theorems of the specific chosen parity-check matrix of QC-LDPC codes without small stopping sets and small girth are proposed. A novel construction for QC-LDPC codes with long block lengths is presented by multiplying mmin or the multiple of mmin, which is the minimum order of the identity matrix for the chosen parity-check matrix. The simulation results show that the specific chosen parity-check matrix of QC-LDPC codes can effectively avoid specified stopping sets and small girth and exhibit excellent BER performance than random LDPC codes with the same longer codes length.

关键词： quasi-cyclic low-density parity-check codes stoppingset stopping distance girth circulant matrices.

Surviving rate of graphs and Firefighter Problem

在线全文

学校读者我要写书评

暂无评论

Frontiers of Mathematics in China 2022年第2期17卷 227-254页

作者： Weifan WANG Jiangxu kong Department of Mathematics Zhejiang Normal UniversityJinhua 321004China

The Firefighter Problem on a graph can be viewed as a simplified model of the spread of contagion,fire,rumor,computer virus,*** fire breaks out at one or more vertices in a graph at the first round,and the firefighter chooses some vertices to *** fire spreads to all non-protected neighbors at the beginning of each *** process stops when the fire can no longer *** Firefighter Problem has attracted considerable attention since it was introduced in *** this paper we provide a survey on recent research progress of this field,including algorithms and complexity,Firefighter Problem for special graphs(finite and infinite)and digraphs,surviving rate and burning number of *** also collect some open problems and possible research subjects.

关键词： Graph network Firefighter Problem surviving rate burning number

Weather and traffic accidents in Hong kong

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

Journal of Geographical Sciences 1998年第3期8卷 93-98页

作者： Yuk Yee Yan Department of Geography Hong kong Baptist University Kowloon Tong, Hong kong

The influence of rainfall and thermal stress in accident occurrence for the period 1985 through 1994 in Hong kong was investigated. The existence of seasonal variations and weekly cycle was also examined. Daity accident and meteorological data were obtained from the Transport Department and the Hong kong Observatory respectively. Utilizing regression analyses and ANOVA, it is discovered that seasonal variation was not important in contributing traffic accidents, and Saturday peak was not ascertained. A non linear relationship between accident occurrence and various rain conditions was found. Accident numbers increased till rain exceeded 50.0 mm. High traffic volume and low speed urban driving in Hong kong can be the major cause of traffic accidents on rainy days. The impact of heat stress on accident occurrence was found to be statistically significant.

关键词： traffic accidents rainfall thermal stress clo.

Spiking-free HGO-based DSC for flexible joint manipulator

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2022年第3期35卷 419-431页

作者： Dezhi kong Wendong WANG Yang WANG Junbo ZHANG Yikai SHI Lingyun kong School of Mechanical Engineering Northwestern Polytechnical University Xi'an 710072China Shaanxi Engineering Research Center of Controllable Neutron Source School of ScienceXijing UniversityXi'an 710123China

The tracking control problem for Flexible Joint Manipulator Control System(FJMCS)with unmeasurable states is addressed in this ***,a High-Gain Observer(HGO)is constructed to estimate the unmeasurable states and the ***,a Dynamic Surface Control(DSC)scheme is developed by using the estimation of *** newly proposed controller has two advantages over the existing methods:(A)a novel Spike Suppression Function(SSF)is developed to avoid the estimation spike problem in the existing HGO-based controllers.(B)Unlike the existing observer-based partial feedback control scheme that can only estimate the unmeasurable states,the proposed HGO can estimate both the unmeasurable states and *** closed-loop system stability is proved by the Lyapunov *** results demonstrate the effectiveness of the proposed controller.

关键词： Dynamic surface control Flexible joint manipulator High-gain observer Mismatched uncertainties Partial states feedback Spike suppression

Design of good QC-LDPC codes without small girth in the p-plane

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2011年第2期22卷 183-187页

作者： Lingjun kong Yang Xiao Institute of Information Science Beijing Jiaotong University Beijing 100044 E R. China Faculty of Information Engineering and Automation Kunming University of Science and Technology Kunming 650500 P. R. China

A construction method based on the p-plane to design high-girth quasi-cyclic low-density parity-check （QC-LDPC） codes is proposed. Firstly the good points in every line of the p-plane can be ascertained through filtering the bad points, because the designed parity-check matrixes using these points have the short cycles in Tanner graph of codes. Then one of the best points from the residual good points of every line in the p-plane will be found, respectively. The optimal point is also singled out according to the bit error rate （BER） performance of the QC-LDPC codes at last. Explicit necessary and sufficient conditions for the QC-LDPC codes to have no short cycles are presented which are in favor of removing the bad points in the p-plane. Since preventing the short cycles also prevents the small stopping sets, the proposed construction method also leads to QC-LDPC codes with a higher stopping distance.

关键词： quasi-cyclic low-density parity-check (QC-LDPC)codes circulant matrices girth stopping set stopping distance.