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An Approximation Algorithm for P-prize-collecting Set Cover Problem

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Journal of the Operations Research Society of China 2023年第1期11卷 207-217页

作者： Jin-Shuang Guo Wen Liu Bo Hou School of Mathematical Sciences Hebei Key Laboratory of Computational Mathematics and ApplicationsHebei Normal UniversityShijiazhuang050024HebeiChina

In this paper,we consider the P-prize-collecting set cover(P-PCSC)problem,which is a generalization of the set cover problem.In this problem,we are given a set system(U,S),where U is a ground set and S⊆2U is a collection of subsets satisfying∪S∈SS=U.Every subset in S has a nonnegative cost,and every element in U has a nonnegative penalty cost and a nonnegative profit.Our goal is to find a subcollection C⊆S such that the total cost,consisting of the cost of subsets in C and the penalty cost of the elements not covered by C,is minimized and at the same time the combined profit of the elements covered by C is at least P,a specified profit bound.Our main work is to obtain a 2f+ε-approximation algorithm for the P-PCSC problem by using the primal-dual and Lagrangian relaxation methods,where f is the maximum frequency of an element in the given set system(U,S)andεis a fixed positive number.

关键词： P-prize-collecting set cover problem Approximation algorithm Primal-dual Lagrangian relaxation

Unconventional 2D Periodic Nanopatterns Based on Block Molecules

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高分子科学:英文版 2023年第10期41卷 1508-1524页

作者： Bo Hou Wen-Bin Zhang Yu Shao Beijing National Laboratory for Molecular Sciences Key Laboratory of Polymer Chemistry&Physics of Ministry of EducationCenter for Soft Matter Science and EngineeringCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing100871China

This review summarizes the self-assembly of block molecules forming unconventional two-dimensional(2D)periodic nanopatterns.Especially,we emphasize the structural evolution from simple columnar phases to complex 2D tiling morphologies in soft materials including block copolymers,liquid crystals,giant molecules,etc.Then,the state-of-the-art nanofabrication technologies for making sophisticated nanostructures with specific functions via combining both bottom-up assembly and top-down lithography-based methods are discussed,highlighting the use of directed self-assembly processes.Finally,we provide our perspective on this area.By further increasing the complexity of block molecules and the designability of lithography,low-dimensional ordered morphologies will be particularly promising for further application in nanotechnology.

关键词： Two-dimensional ordered morphologies Block molecules Directed self-assembly Nanofabrication Tilings and patterns

In situ growth CNT@MOFs core-shell structures enabling high specific supercapacitances in neutral aqueous electrolyte

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Nano Research 2022年第7期15卷 6112-6120页

作者： Mingxia Lu Gang Wang Xiping Yang Bo Hou School of Chemistry and Chemical Engineering Henan University of TechnologyZhengzhou 450001China School of Physics and Astronomy Cardiff UniversityCardiff CF243AAUK

Conductive metal-organic frameworks(c-MOFs)are promising active electrode materials for electrochemical double-layer capacitors with a performance that already exceeds most carbon-based materials.However,their excellent supercapacitance is primarily based on organic or alkaline electrolytes,which largely impede their broad applications and sustainabilities.In this work,we propose a new synthesis approach for fabricating carbon nanotubes and c-MOFs(CNT@MOFs)core–shell structures,which result in high supercapacitance in neutral aqueous electrolytes.We identify that CNTs provide abundant active sites to ensure high capacitance,and Ni3(2,3,6,7,10,11-hexaiminotriphenylene(HITP))2 nanoarrays that in situ grow on the surface of CNTs bundles can significantly improve the conductivity and provide enough ion transport pathways in aqueous electrolytes.Specifically,using CNT@MOFs core-shell structures as an electrode,we obtained a high initial capacitance of 150.7 F·g^(−1) at 0.1 A·g^(−1) in 1 M Na2SO4 solution and good capacity retention of 83.5%after 10,000 cycles at 4 A·g^(−1).We also found that the carboxyl groups on the surface of CNTs provide better anchor sites for the in situ growth of c-MOF,which promotes the uniform growth of c-MOF shells on the CNT surface and improves aqueous electrolyte accessibility.We believe that the high supercapacitance in aqueous electrolytes reported in this work would provide a good prospect for deploying c-MOF based energy storage devices into biomedical and other healthcare electronic applications.

关键词： carbon nanotubes metal-organic frameworks(MOFs) conductive MOFs supercapacitor neutral aqueous electrolyte

The Folded(2D+1)-cube and Its Uniform Posets

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Acta Mathematicae Applicatae Sinica 2018年第2期34卷 281-292页

作者： Li-hang hou Bo Hou Suo-gang GAO College of Mathematics and Information Science Hebei Normal University

Let F denote the folded （2D ＋ 1）-cube with vertex set X and diameter D ≥ 3. Fix x∈ X. We first define a partial order ≤ on X as follows. For y,z ∈ X let y ≤ z whenever （x,y）＋（y,z） =- （x, z）. Let R （resp. L） denote the raising matrix （resp. lowering matrix） of P. Next we show that there exists a certain linear dependency among RL2, LRL, L2R and L for each given Q-polynomial structure of F. Finally, we determine whether the above linear dependency structure gives this poser a uniform structure or strongly uniform structure.

关键词： distance-regular graph the folded （2D ＋ 1）-cube uniform poset

Limited-Budget Consensus Design and Analysis for Multiagent Systems With Switching Topologies and Intermittent Communications

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IEEE/CAA Journal of Automatica Sinica 2021年第10期8卷 1724-1736页

作者： Le Wang Jianxiang Xi Bo Hou Guangbin Liu Force University of Engineering Xi’an 710025China

This paper investigates limited-budget consensus design and analysis problems of general high-order multiagent systems with intermittent communications and switching topologies.The main contribution of this paper is that the tradeoff design between the energy consumption and the consensus performance can be realized while achieving leaderless or leaderfollowing consensus,under constraints of limited budgets and intermittent communications.Firstly,a new intermittent limitedbudget consensus control protocol with a practical trade-off design index is proposed,where the total budget of the whole multiagent system is limited.Then,leaderless limited-budget consensus design and analysis criteria are derived,in which the matrix variables of linear matrix inequalities are determined according to the total budget and the practical trade-off design parameters.Meanwhile,an explicit formulation of the consensus function is derived to describe the consensus state trajectory of the whole system.Moreover,a new two-stage transformation strategy is utilized for leader-following cases,by which the dynamics decomposition of leaderless and leader-following cases can be converted into a unified framework,and sufficient conditions of the leader-following limited-budget consensus design and analysis are determined via those of the leaderless cases.Finally,numerical simulations are given to illustrate theoretical results.

关键词： Intermittent communication limited-budget consensus multiagent system switching topology

Superior strength-plasticity synergy in a heterogeneous lamellar Ti_(2)AlC/TiAl composite with unique interfacial microstructure

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Journal of Materials Science & Technology 2023年第28期159卷 21-32页

作者： Pei Liu Bo Hou Aiqin Wang Jingpei Xie Zhenbo Wang Feng Ye College of Materials Science and Engineering Henan University of Science and TechnologyLuoyang 471023China Provincial and Ministerial Co-construction of Collaborative Innovation Center for Non-ferrous Metal New Materials and Advanced Processing Technology Luoyang 471023China State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China

Improving the plasticity of TiAl alloys at room temperature has been a longstanding challenge for the de-velopment of next-generation aerospace engines.By adopting the nacre-like architecture design strategy,we have obtained a novel heterogeneous lamellar Ti_(2)AlC/TiAl composite with superior strength-plasticity synergy,i.e.,compressive strength of∼2065 MPa and fracture strain of∼27%.A combination of micropil-lar compression and large-scale atomistic simulation has revealed that the superior strength-plasticity synergy is attributed to the collaboration of Ti_(2)AlC reinforcement,lamellar architecture and heteroge-neous interface.More specifically,multiple deformation modes in Ti_(2)AlC,i.e.,basal-plane dislocations,atomic-scale ripples and kink bands,could be activated during the compression,thus promoting the plas-tic deformation capability of composite.Meanwhile,the lamellar architecture could not only induce sig-nificant stress redistribution and crack deflection between Ti_(2)AlC and TiAl,but also generate high-density SFs and DTs interactions in TiAl,leading to an improved strength and strain hardening ability.In addi-tion,profuse unique Ti_(2)AlC(1¯10¯3)/TiAl(111)interfaces in the composite could dramatically contribute to the strength and plasticity due to the interface-mediated dislocation nucleation and obstruction mecha-nisms.These findings offer a promising paradigm for tailoring microstructure of TiAl matrix composites with extraordinary strength and plasticity at ambient temperature.

关键词： Ti_(2)AlC/TiAl composite Heterogeneous lamellar microstructure Micropillar compression Interface-mediated deformation Strength-plasticity synergy

Hypercube and Tetrahedron Algebra

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Chinese Annals of Mathematics,Series B 2015年第2期36卷 293-306页

作者： Bo Hou Suogang GAO College of Mathematics and Information Science Hebei Normal University

Let D be an integer at least 3 and let H(D, 2) denote the hypercube. It is known that H(D, 2) is a Q-polynomial distance-regular graph with diameter D, and its eigenvalue sequence and its dual eigenvalue sequence are all {D-2i}D i=0. Suppose that denotes the tetrahedron algebra. In this paper, the authors display an action of ■ on the standard module V of H(D, 2). To describe this action, the authors define six matrices in Mat X(C), called A, A*, B, B*, K, K*.Moreover, for each matrix above, the authors compute the transpose and then compute the transpose of each generator of ■ on V.

关键词：超立方体四面体代数特征值序列距离正则图标准模块多项式发电机

Hochschild cohomology of Zn-Galois coverings of an algebra

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Frontiers of Mathematics in China 2012年第6期7卷 1113-1128页

作者： Bo Hou Jinmei FAN School of Mathematics and Information Science Henan University Kaifeng 475001 China College of Applied Science Beijing University of Technology Beijing 100124 China College of Science Guilin Universi-ty of Technology Guilin 541004 China

We consider the Zn-Galois covering An of the algebra A introduced by F. Xu [Adv. Math., 2008, 219： 1872-1893]. We calculate the dimensions of all Hochschild cohomology groups of An and give the ring structure of the Hochschild cohomology ring modulo nilpotence. As a conclusion, we provide a class of counterexamples to Snashall-Solberg＇s conjecture.

关键词： Hochschild cohomology Galois covering Koszul algebra

Engineering Bioinspired Nanomedicines to Mitigate the Resistance to Cancer Immunotherapy

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Accounts of Materials Research 2022年第7期3卷 697-708页

作者： Jiayi Ye Bo Hou Madiha Saeed Zhiai Xu Haijun Yu Center of Pharmaceutics Shanghai Institute of Materia MedicaChinese Academy of SciencesShanghai 201203China University of Chinese Academy of Sciences Beijing 100049China School of Chemistry and Molecular Engineering East China Normal UniversityShanghai 200241China

CONSPECTUS:The current era has witnessed the success of immunotherapy,in particular,immune checkpoint blockade(ICB)therapy,at an unprecedented pace.However,immunotherapy often fails to unleash the antitumor immune response because of the paucity of appropriate therapeutic targets in the complex tumor microenvironment(TME)and the occurrence of intrinsic and adaptive immune resistance of tumor cells.In recent years,we have rationally engineered a set of bioinspired stimuli-activatable nanotherapeutics to circumvent cancer immune resistance and potentiate cancer immunotherapy.

关键词： immunotherapy cancer Cancer