检索结果-南通市图书馆

Effects of physical properties of supercritical water on coarse graining of particle cluster

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Particuology 2023年第11期82卷 166-178页

作者： xiaoyu li Huibo Wang Yi li Hui Jin State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an710049China

The coarse graining of particle cluster is of great significance to the study of a fluidized bed. The effects of variations in the physical properties of supercritical water on the coarse graining of particle cluster are investigated in this work. The drag coefficient distributions of the particle cluster are not influenced by the physical properties. However, the physical properties have effects on the values of drag coefficient. The effects of physical properties are weaker in the case of large particle concentrations. Furthermore, the physical properties lead to that the effect of particle cluster wake on the drag of downstream particles being significantly different from that of constant property flow. The variation trend of drag of coarse graining particle is consistent with that of isolated particle. The physical properties lead to significant differences in the values of drag. In this paper, the dominance of the effects of physical properties in a variety of cases is confirmed. Finally, a physical properties effect model is developed accordingly.

关键词： Supercritical water Variations in physical properties Fluidized bed Coarse grain method Particle drag

Numerical simulation of droplet impacting liquid surface by SPH

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2011年第7期54卷 1873-1880页

作者： li DaMing li xiaoyu liN Yi School of Civil Engineering &Key Laboratory of Harbor &Ocean Engineering Ministry of Education Tianjin University Tianjin 300072 China Institute of Tianjin Meteorological Bureau Tianjin 300074 China

Droplet impacting liquid surface is not only the extremely prevalent phenomenon in the nature and industrial production but also the extremely complicated problem of strong non-linear transient impact and free-surface flow. On the basis of the two-dimensional viscous incompressible N-S equations, this paper conducts a study of numerical simulation on the problem of droplet impacting liquid surface （water beads） of water container in certain initial velocity by the method of SPH （smoothed particle hydrodynamics）. The effect of surface tension is considered between surface particles by searching the free surface particles in the course of study; the effect of initial impact has been solved by use of artificial viscosity; at the same time, the side-wall virtual particles and image virtual particles are both introduced to deal with the boundary condition, which has solved the boundary defects quite well and eliminated the instability of real particles dropped to the comer of container. The calculated results form the distribution chart of particles, flow field chart, pressure chart and the displacement and velocity variation curve of different particles. The comparison between simulated results and experimental photos shows that the simulation is effective. This paper compares the variational curves for fluctuations of liquid surface qualitatively through adopting the methods of level-set, BEM and SPH, respectively at last. The simulated results show that it will produce strong non-linear phenomena, such as the splash of liquid, discrete liquid surface, and strong wave of free liquid surface, when the droplet impacts liquid surface; in the course of impacting, the movement of liquid particles exhibits the characteristic of oscillation; the method of SPH has certain advantages of dealing with the large deformation problem of free surface.

关键词： SPH the process of droplet impact free surface numerical simulation

Non-spherical polymersomes driven by directional aromatic interactions

在线全文

学校读者我要写书评

暂无评论

Science China Materials 2018年第3期61卷 437-438页

作者： Mingyan Luo Yunjun Luo xiaoyu li School of Materials Science and Engineering Beijing Institute of Technology

Polymersomes,nanoscopic polymer vesicles self-assembled from synthetic block copolymers,are ideal candidates for drug delivery and synthetic biology,due to their characteristic of high stability,chemical

关键词： PEG NIPAM Nature Non-spherical polymersomes driven by directional aromatic interactions THF

Practical Cryptanalysis of a Public Key Cryptosystem Based on the Morphism of Polynomials Problem

在线全文

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2018年第6期23卷 671-679页

作者： Jaihui Chen Chik How Tan xiaoyu li School of Computer Guangdong University of Technology Guangzhou 510006 China Temasek Laboratories NationalUniversity of Singapore Singapore 117411 Singapore the School of Computer Zhengzhou University of Aeronautics Zhengzhou 450046 China

Multivariate Public Key Cryptography （MPKC） has intensively and rapidly developed during the past three decades. MPKC is a promising candidate for post-quantum cryptography. However, designing it is universally regarded as a difficult task to design a secure MPKC foundation scheme, such as an encryption scheme and key exchange scheme. In this work, we investigate the security of a new public key cryptosystem that is based on the Morphism of Polynomials （MP）. The public key cryptosystem proposed by Wang et al. （Wuhan University, China） comprises a key exchange scheme and encryption scheme. Its security can be provably reduced to the hardness of solving a new difficult problem, namely, the Decisional Multivariate Diffie Hellman （DMDH） problem. This problem Js a variant of the MP problem, which is difficult to solve by random systems. We present a proposition that reduces the DMDH problem to an easy example of the MP problem. Then, we propose an efficient algorithm for the Key Recover Attack （KRA） on the schemes of the public key cryptosystem. In practice, we are able to entirely break the cryptosystem＇s claimed parameter of 96 security levels in less than 17.252 s. Furthermore, we show that finding parameters that yield a secure and practical scheme is impossible.

关键词： cryptanalysis post-quantum cryptography multivariate public key cryptosystems morphism ofpolynomials problem

The Origins of Toroidal Micelles from a liquid-crystalline Triblock Copolymer

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2020年第12期38卷 1709-1717页

作者： Bixin Jin Guojun liu xiaoyu li School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China Department of Chemistry Queen's University90 Bader LaneKingstonOntarioCanada Key Laboratory of High Energy Density Materials Ministry of EducationBeijing Institute of TechnologyBeijing 100081China Experimental Centre of Advanced Materials Beijing Institute of TechnologyBeijing 100081China

of main observation and conclusion In this paper,we reported a systematic study on the formation mechanism of bent toroidal micelles from a triblock copolymer poly(acrylic acid)-block-(2-cinnamoyloxylethyl methacrylate)-block-poly(perfluorooctylethyl methacrylate)(PAA-b-PCEMA-b-PFMA)in the binary solvent mixture of methanol and a,a,a-trifluorotoluene(MeOH/TFT)through a heating-cooling *** was found that the formation process of toroids was predominantly kinetic-controlled,and can be influenced by the preparation protocol,solvent composition and stirring rate of the *** toroids were formed via a complicated morphological transition *** high temperature,the polymer formed bilayered vesicles with bumpy surface,while upon cooling,the vesicles broke and unfolded into bumpy platelet micelles,which subsequently perforated into toroidal and cylindrical micelles upon further *** the distinct and unique bumpy vesicle and platelet structures,the transformation mechanisms from vesicular to platelet,and toroidal micelles are also very intriguing,and may provide new insights into the interconversion of micellar morphologies.

关键词： process. crystalline stirring

Molecular mechanisms of cellular metabolic homeostasis in stem cells

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Oral Science 2023年第4期15卷 527-539页

作者： xiaoyu li Ou Jiang Songlin Wang Salivary Gland Disease Center and Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction Beijing Laboratory of Oral Health and Beijing Stomatological HospitalCapital Medical UniversityBeijingChina Department of Biochemistry and Molecular Biology School of Basic Medical SciencesCapital Medical UniversityBeijingChina Immunology Research Center for Oral and Systemic Health Beijing Friendship HospitalCapital Medical UniversityBeijingChina Laboratory for Oral and General Health Integration and Translation Beijing Tiantan HospitalCapital Medical UniversityBeijingChina Research Unit of Tooth Development and Regeneration Chinese Academy of Medical SciencesBeijingChina

Many tissues and organ systems have intrinsic regeneration capabilities that are largely driven and maintained by tissue-resident stem cell populations. In recent years, growing evidence has demonstrated that cellular metabolic homeostasis plays a central role in mediating stem cell fate, tissue regeneration, and homeostasis. Thus, a thorough understanding of the mechanisms that regulate metabolic homeostasis in stem cells may contribute to our knowledge on how tissue homeostasis is maintained and provide novel insights for disease management. In this review, we summarize the known relationship between the regulation of metabolic homeostasis and molecular pathways in stem cells. We also discuss potential targets of metabolic homeostasis in disease therapy and describe the current limitations and future directions in the development of these novel therapeutic targets.

关键词： homeostasis maintained mechanisms

Effects of physical properties of supercritical water on heat transfer characteristics of single particle within a particle cluster Author links open overlay panel

在线全文

学校读者我要写书评

暂无评论

Particuology 2024年第8期91卷 291-302页

作者： xiaoyu li Bowei Zhang Huibo Wang Hui Jin State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an710049China

The complex physical properties of supercritical water(SCW)make the heat transfer characteristics of particles within a particle cluster *** heat transfer characteristics of single particle within a particle cluster in SCW,influenced by surrounding particles,have not been effectively *** numerical simulations were conducted to investigate the heat transfer characteristics of particle clusters in SCW under different *** results were compared and analyzed with those from constant property *** was found that Reynolds number(Re)and the void fraction of particle cluster have no special effects on the variation trends of Nusselt number(Nu)for the focused ***,the particle temperature had a significant effect on the variation trends of *** effect of Re on the heat transfer rate exponent(η)of the focused particle can be divided into two zones:a significant effect zone and a non-significant effect *** effect of void fraction onηin the non-significant effect zone was *** the non-significant effect zone,ηdecreased with the increasing particle *** the significant effect zone,the variation trends ofηbecame more *** fundamental reason for this series of phenomena is the changes in distribution of physical properties.A model forηwas developed for the non-significant effect *** model can filter out the effects of Re and certain particle cluster spatial configurations,and it demonstrates good predictive performance.

关键词： Supercritical water Particle cluster Heat transfer characteristics Heat transfer rate exponent Physical properties correction

Amphiphilic Block Copolymer Micelles for Gene Delivery

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2022年第6期38卷 1368-1379页

作者： li Qin JIN Bixin LUO Yunjun li xiaoyu School of Material Science and Engineering Beijing Institute of TechnologyBeijing100081P.R.China Key Laboratory of High Energy Density Materials Ministry of EducationBeijing Institute of TechnologyBeijing100081P.R.China Experimental Centre of Advanced Materials Beijing Institute of TechnologyBeijing100081P.R.China

Gene therapy is a promising method to treat acquired and inherited diseases by introducing exogenous genes into specific recipient *** micelles with different nanoscopic morphologies and properties hold great promise for gene delivery *** cationic polymers,poly(ethyleneimine)(PEI),poly(L-lysine)(PLL),poly(2-dimethylaminoethyl methacrylate)(PDMAEMA)and novel cationic polymers poly(2-oxazoline)s(POxs),have been incorporated into block copolymers and decorated with targeting moieties to enhance transfection *** order to minimize cytotoxicity,nonionic block copolymer micelles are utilized to load gene through hydrophilic and hydrophobic interactions or covalent conjugations,*** our perspective,properties(shape,size,and mechanical stiffness,etc.)of block copolymer micelles may significantly affect cytotoxicity,transfection efficiency,circulation time,and load capacity of gene vectors in vivo and in *** review briefly sums up recent efforts in cationic and nonionic amphiphilic polymeric micelles for gene delivery.

关键词： Polymeric micelle Block copolymer Gene delivery

A numerical investigation on heat transfer characteristics of a particle cluster in fluid with variable properties

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2024年第11期94卷 327-344页

作者： xiaoyu li Huibo Wang Bowei Zhang Hui Jin State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an710049China

This work investigates the heat transfer characteristics of particle clusters under the effects of the complex properties of supercritical water(SCW).It analyzes the heat transfer characteristics of sub-particles and the average heat transfer characteristics of particle *** results reveal a phenomenon of shifting positions of high specific heat *** led to variations in the dimensionless heat transfer coefficient ***,the results indicate that as the heat transfer process strengthens,the effects of variations in property distribution on heat transfer tends to *** on this conclusion,the effects of variations in property distribution on heat transfer are categorized into Stable Effects Region and Non-Stable Effects *** utilizing the principles of fluid flow-heat transfer coupling and similarity,a heat transfer prediction model for particle clusters in SCW is established.

关键词： Heat transfer Supercritical water Particle cluster Modeling