检索结果-南通市图书馆

Two Matrix Theorems Arising from Nilpotent Groups

在线全文

学校读者我要写书评

暂无评论

Algebra Colloquium 2024年第3期31卷 499-504页

作者： jing zhao Heguo Liu School of Mathematics and Statistics Hainan University Haikou 570228China

For a nilpotent group G without π-torsion,and x,y ∈ G,if x^(n)=y^(n) for a T-number n,then x=y;if x^(m)y^(n)=y^(n)x^(m) for n-numbers m,n,then xy=*** is a wellknown result in group *** this paper,we prove two analogous theorems on matrices,which have independence ***,let m be a given positive integer and A a complex square matrix satisfying that(i)all eigenvalues of A are nonnegative,and(i)rank A^(2)=rank A;then A has a unique m-th root X with rank X^(2)=rank X,all eigenvalues of X are nonnegative,and moreover there is a polynomial f(λ)with X=f(A).In addition,let A and B be complex n×n matrices with all eigenvalues nonnegative,and rank A^(2)=rank A,rank B^(2)=rank B;then(i)A=B when A^(r)=B^(r) for some positive integer r,and(i)AB=BA when A^(s)B^(t)=B^(t)A^(s) for two positive integers s and t.

关键词： nilpotent group root matrix Chinese remainder theorem

Study of deep transportation and plugging performance of deformable gel particles in porous media

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

Petroleum Science 2024年第2期21卷 962-973页

作者： Wen-jing zhao jing Wang Zhong-Yang Qi Hui-Qing Liu National Key Laboratory of Petroleum Resources and Engineering China University of PetroleumBeijing102249China MOE Key Laboratory of Petroleum Engineering China University of PetroleumBeijing102249China

Deformable gel particles(DGPs) possess the capability of deep profile control and flooding. However, the deep migration behavior and plugging mechanism along their path remain unclear. Breakage, an inevitable phenomenon during particle migration, significantly impacts the deep plugging effect. Due to the complexity of the process, few studies have been conducted on this subject. In this paper, we conducted DGP flow experiments using a physical model of a multi-point sandpack under various injection rates and particle sizes. Particle size and concentration tests were performed at each measurement point to investigate the transportation behavior of particles in the deep part of the reservoir. The residual resistance coefficient and concentration changes along the porous media were combined to analyze the plugging performance of DGPs. Furthermore, the particle breakage along their path was revealed by analyzing the changes in particle size along the way. A mathematical model of breakage and concentration changes along the path was established. The results showed that the passage after breakage is a significant migration behavior of particles in porous media. The particles were reduced to less than half of their initial size at the front of the porous media. Breakage is an essential reason for the continuous decreases in particle concentration, size, and residual resistance coefficient. However, the particles can remain in porous media after breakage and play a significant role in deep plugging. Higher injection rates or larger particle sizes resulted in faster breakage along the injection direction, higher degrees of breakage, and faster decreases in residual resistance coefficient along the path. These conditions also led to a weaker deep plugging ability. Smaller particles were more evenly retained along the path, but more particles flowed out of the porous media, resulting in a poor deep plugging effect. The particle size is a function of particle size before inject

关键词： Physical simulation Deformable gel particle Breakage Particle size Residual resistance coefficient

Phylogenetic analysis of bacterial community in deep-sea sediment from the western Pacific “warm pool”

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2005年第5期24卷 127-138页

作者： zhao jing ZENG Runying School of Life Sciences Xiamen University Xiamen 361005 China Key Laboratory of Marine Biogenetic Resources Third Institute of Oceanography State Oceanic Administration Xiamen 361005 China

A depth profile of bacterial community structure in one deep-sea sediment core of the western Pacific ＂warm pool＂（WP） was investigated and compared with that in a sediment sample from the eastern Pacific （EP） by phylogenetic analysis of 16S rDNA fragments. Five bacterial 16S rDNA clone libraries were constructed, and 133 clones with different restriction fragment length polymorphism （RFLP） patterns were sequenced. A phylogenetic analysis of these sequences revealed that the bacterial diversity in a sample from the WP was more abundant than that in the EP sample. The bacterial population in the sediment core of WP was composed of eight major lineages of the domain bacteria. Among them the γ-Proteobacteria was the predominant and most diverse group in each section of WP sediment core, followed by the α-Proteobacteria. The genus Colwellia belonging to γ-Proteobacteria was predominant in this sample. The shift of bacterial communities among different sections of the WP sediment core was δ-, ε-Proteobacteria, and Cytopahga-Flexibacteria-Bacteroides （CFB） group. The ratios between them in the bacterial communities all showed inversely proportional to the depth of sediment. The sequences related to sulphate reducing bacteria （SRB） were detected in every section. The bacterial community structure in this sediment core might be related to the environmental characteristics of the surface seawater of the western Pacific WP.

关键词： western Pacific "warm pool" deep-sea sediment bacterial community

Transition metal clusters with precise numbers of atoms anchored on graphdiyne as multifunctional electrocatalysts for OER/ORR/HER:a computational study

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2024年第7期43卷 3107-3117页

作者： Xin-Yang Liu jing-Wei Liu Gang Li jing-Xiang zhao College of Chemistry and Chemical Engineering Harbin Normal UniversityHarbin 150025China

Subnanometer metal clusters play an increasingly important role in heterogeneous catalysis due to their high catalytic activity and *** this work,by means of the density functional theory(DFT) calculations,the catalytic activities of transition metal clusters with precise numbers of atoms supported on graphdiyne(TM_(1-4)@GDY,TM=V,Cr,Mn,Fe,Co,Ni,Cu,Ru,Rh,Pd,Ir,Pt) were investigated for oxygen evolution reactions(OER),oxygen reduction reactions(ORR) and hydrogen evolution reactions(HER).The computed results reveal that the Pd_(2),Pd_(4) and Pt_(1) anchored graphdiyne can serve as trifunctional catalysts for OER/ORR/HER with the overpotentials of 0.49/0.37/0.06,0.45/0.33/0.12 and 0.37/0.43/0.01 V,respectively,while Pd_(1) and Pt_(2)@graphdiyne can exhibit excellent catalytic performance for water splitting(OER/HER) with the overpotentials of 0.55/0.17 and 0.43/0.03 *** addition,Ni_(1) and Pd_(3) anchored GDY can perform as bifunctional catalysts for metal-air cells(OER/ORR) and fuels cells(ORR/HER) with the overpotentials of 0.34/0.32 and 0.42/0.04 V,***,by precisely controlling the numbers of atoms in clusters,the TM_(1-4) anchored graphdiyne can serve as promising multifunctional electrocatalysts for OER/ORR/HER,which may provide an instructive strategy to design catalysts for the energy conversation and storage devices.

关键词： Density functional theory Graphdiyne Single-cluster catalysts Multifunctional electrocatalysts Overpotential

在线全文

学校读者我要写书评

暂无评论

On P-sober Spaces

Acta Mathematica Sinica,English Series 2023年第9期39卷 1768-1780页

作者： Yu jing Zhang Bin zhao School of Mathematics and Statistics Shaanxi Normal UniversityXi’an710119P.R.China

In this paper,we focus on p-sober spaces and prove that(1)the To space X is p-sober if and only if the Smyth power space of X is p-sober;(2)the space X has a p-sober dcpo model if and only if X is T_(1)and p-sober;(3)every non-p-sober T_(0)space does not have a p-sobrification;(4)the T_(0)space X is sober if and only if X is p-sober and PD.

关键词： P-sober dcpo poset model of topological space p-sobrification

Stationary Patterns of a Ratio-dependent Prey-predator Model with Cross-diffusion

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2017年第2期33卷 497-504页

作者： jing-fu zhao Hong-tao ZHANG jing YANG School of Science Zhongyuan University of Technology Zhengzhou 450007 China

This paper is concerned with a ratio-dependent predator-prey system with diffusion and cross- diffusion in a bounded domain with no flux boundary condition. We show that under certain hypotheses, the cross-diffusion c... 详细信息

关键词： existence predator-prey system cross-diffusion positive steady state ratio-dependence topolog-ical degree

Continuous Dependence for Stochastic Functional Differential Equations with State-Dependent Regime-Switching on Initial Values

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2021年第3期37卷 389-407页

作者： jing Hai SHAO Kun zhao Center for Applied Mathematics Tianjin UniversityTianjin 300072P.R.China

This work is concerned with the continuous dependence on initial values of solutions of stochastic functional differential equations(SFDEs) with state-dependent regime-switching. Due to the state-dependence, this problem is very different to the corresponding problem for SFDEs without switching or SFDEs with Markovian switching. We provide a method to overcome the intensive interaction between the continuous component and the discrete component based on a subtle application of Skorokhod’s representation for jumping processes. Furthermore, we establish the strong convergence of Euler–Maruyama’s approximations, and estimate the order of error. The continuous dependence on initial values of Euler–Maruyama’s approximations is also investigated in the end.

关键词： Regime-switching state-dependent Euler–Maruyama’s approximation

Chemical Measurement and Analysis: from Phenomenon to Essence

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2022年第16期40卷 1975-1986页

作者： Wei zhao jing-Juan Xu State Key Laboratory of Analytical Chemistry for Life Science School of Chemistry and Chemical EngineeringNanjing UniversityNanjingJiangsu210023 China Institute of Nanochemistry and Nanobiology School of Environmental and Chemical EngineeringShanghai UniversityShanghai 2004China

The review summaries our achievements in optical,electrochemical,as well as mass spectrometry analysis and imaging with high sensitivity,specificity,and spatiotemporal *** promoted the plasmonic imaging system,and developed ultra-sensitive plasmonic nanoprobes for the tracking of single molecules in single living cells,as well as plasmonic nanocatalysts for highly efficient energy *** addition,we contributed a lot in electrogenerated chemiluminescence(ECL)analysis and *** works including localized surface plasmon resonance(LSPR)enhanced ECL,ECL ratiometric detection,BPE based ECL system,multi-color ECL sensing as well as super-resolved ECL imaging have been initiated by our ***,we also dedicated in nanopipette based electrochemical analysis in single living cells,as well as ESI-MS analysis on short time scale.

关键词： Biosensors Plasmonic imaging Electrogenerated chemiluminescence Electrochemistry Mass spectrometry

Natural gas hydrate shell model in gas-slurry pipeline flow

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 Natural Gas Chemistry 2010年第3期19卷 261-266页

作者： jing Gong Bohui Shi Jiankui zhao Beijing Key laboratory of Urban Oil and Gas Distribution Technology China University of Petroleum Beijing 102249 China China National Oil and Gas Exploration and Development Corporation Beijing 100034 China

A hydrate shell model coupled with one-dimensional two-fluid pipe flow model was established to study the flow characteristics of gas-hydrate slurry flow *** hydrate shell model was developed with kinetic limitations and mass transfer limitations,and it was solved by Euler *** analysis of influence factors was *** was found that the diffusion coefficient was a key parameter in hydrate forming *** the hydrate kinetics model and the contacting area between gas and water,the hydrate shell model was more close to its practical situations.

关键词： natural gas hydrate shell model gas-slurry pipeline flow