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Q-learning for dynamic channel assignment in cognitive wireless local area network with fibre-connected distributed antennas

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The Journal of china Universities of Posts and Telecommunications 2012年第4期19卷 80-85页

作者： LI Yi JI Hong Key Laboratory of Universal Wireless Communications Ministry of EducationBeijing University of Posts and TelecommunicationsBeijing 100876China

Cognitive wireless local area network with fibre-connected distributed antennas （CWLAN-FDA） is a promising and efficient architecture that combines radio over fiber, cognitive radio and distributed antenna technologies to provide high speed/high capacity wireless access at a reasonable cost. In this paper, a Q-learning approach is applied to implement dynamic channel assignment （DCA） in CWLAN-FDA. The cognitive access points （CAPs） select and assign the best channels among the industrial, scientific, and medical （ISM） band for data packet transmission, given that the objective is to minimize external interference and acquire better network-wide performance. The Q-learning method avoids solving complex optimization problem while being able to explore the states of a CWLAN-FDA system during normal operations. Simulation results reveal that the proposed strategy is effective in reducing outage probability and improving network throughput.

关键词： cognitive WLAN fibre-connected distributed antennas Q-learning dynamic channel assignment

Topochemical polymerization of hydrogen-bonded organic framework for supporting ultrafine palladium nanoparticles

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science china Chemistry 2023年第7期66卷 2019-2027页

作者： Xu Ding Bin Han Baoqiu Yu Hailong Wang Jianzhuang Jiang Beijing Advanced Innovation Center for Materials Genome Engineering Beijing Key Laboratory for Science and Application of Functional Molecular and Crystalline MaterialsDepartment of Chemistry and Chemical EngineeringSchool of Chemistry and Biological EngineeringUniversity of Science and Technology BeijingBeijing 100083China

Topochemical polymerization of molecular crystals into porous materials is of significance due to their promising applications in the field of adsorption and catalysis,yet rarely reported due to the synthesis ***,a hydrogen-bonded organic framework(HOF-45)has been fabricated by the crystallization of a cage-like building block containing three alkynyl *** exhibits almost mesoporous structure demonstrated by single crystal X-ray diffraction ***-driven topochemical polymerization of HOF-45 with ethanedithiol covalently links alkynyl groups in HOF-45,generating a hydrogen-bond and covalentbond cross-linked material(HOF-45C).In contrast to HOF-45,cross-linked HOF-45C retains the crystalline nature and displays improved solution resistence according to the powder X-ray diffraction *** particular,HOF-45C is able to support the growth of ultrafine palladium nanoparticles with the average size of ca.1.9 nm for rapidly promoting the degradation of nitrophenol,methyl orange,and congo red with the help of NaBH_(4)as well as Suzuki-Miyaura coupling *** work inputs a new idea on the HOFs application in preparing covalent-linked porous organic materials.

关键词： hydrogen-bonded organic frameworks topochemical polymerization palladium nanoparticles nitrophenol degradation organic dyes degradation Suzuki-Miyaura coupling reaction

Evidences of rapid erosion driven by climate in the Yarlung Zangbo (Tsangpo) Great Canyon,the eastern Himalayan syntaxis

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Chinese science Bulletin 2011年第11期56卷 1123-1130页

作者： YU XiangJiang JI JianQing GONG JunFeng SUN DongXia QING JianChun WANG LiNing ZHONG DaLai ZHANG ZhiCheng Key Laboratory of Orogenic Belts and Crustal Evolution School of Earth and Space Sciences Peking University Beijing 100871 China Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China

Climate and tectonism are both particularly intense in the Yarlung Zangbo (Tsangpo) Great Canyon in the eastern Himalayan syntaxis,which is characterized by the most rapid landscape evolution of anywhere in the ***,the eastern Himalayan syntaxis is one of the best locations to study the interactions between climate and *** paper investigates the cooling ages of the Doxong La-Baibung profile using apatite fission track (AFT) dating on 11 bedrock samples at elevations ranging from 4210 to 710 *** are topographic,climatic,metamorphic,and thermochronological gradients in the profile,providing good conditions to study interactions between climate and *** ages ranged from 4.6±0.6 Ma to 1.7±0.3 Ma,and the mean fission track lengths ranged from 11.0 to 12.4 μ*** was found that the cooling rates revealed by AFT ages increased with decreasing ***,the tendency of the cooling rates revealed by the 40 Ar-39 Ar ages was different from that indicated by the AFT ***,for most districts of the eastern Himalayan syntaxis,the compiled AFT age distribution correlates well with the annual average precipitation,indicating the coupling of the cooling and erosion rates of the near-surface rock and *** geothermal history modeling results indicate an obvious increase in the cooling and erosion rate between 1.0 and 0.5 *** age is consistent with other research findings for this time,when the vapor channel of the Yarlung Zangbo Great Canyon began to take *** evidences suggest that climate,especially precipitation,has acting as a key factor influencing the rapid cooling and erosion in the Yarlung Zangbo Great Canyon since 1-0.5 Ma.

关键词：东喜马拉雅构造结雅鲁藏布江大峡谷雅鲁藏布大峡谷侵蚀速率气候证据年平均降水量冷却年龄

Simulation and experimental analysis of supporting characteristics of multiple oil pad hydrostatic bearing disk

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Journal of Hydrodynamics 2013年第2期25卷 236-241页

作者：张艳芹范立国李锐戴春喜于晓东 College of Mechanical and Power Engineering Harbin University of Science and Technology

To study the heavy hydrostatic bearing with multiple oil pads, a reasonably simplified model of the pad is put forward, and the mathematical model of the bearing characteristics of the multiple oil pad hydrostatic bearing is built with consideration of variable viscosity. The pressure field in the clearance oil film of the hydrostatic bearing at various velocities is simulated based on the Finite Volume Method （FVM） by using the software of Computational Fluid Dynamics （CFD）. Some pressure experiments on the hydrostatic bearing were carried out and the results verified the rationality of the simplified model of the pad and the validity of the numerical simulation. It is concluded that the viscosity has a great influence on the pressure in the heavy hydrostatic bearing and cannot be neglected, especially, in cases of high rotating speed. The results of numerical calculations provide the internal flow states inside the bearing, which would help the design of the oil cavity structure of the bearing in engineering practice.

关键词： hydrostatic bearing oil pad supporting characteristics Finite Volume Method (FVM)

Powder metallurgical Ti-Mg metal-metal composites facilitate osteoconduction and osseointegration for orthopedic application

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Bioactive Materials 2019年第1期4卷 37-42页

作者： Sihui Ouyang Qianli Huang Yong Liu Zhengxiao Ouyang Luxin Liang State Key Lab of Powder Metallurgy Central South UniversityChangsha410083PR China Department of Orthopedics The Second Xiangya HospitalCentral South UniversityChangshaHunanPR China

In this work,TieMg metal-metal composites(MMCs)were successfully fabricated by spark plasma sintering(SPS).In vitro,the proliferation and differentiation of SaOS-2 cells in response to TieMg metal-metal composites(MMCs)were *** vivo,a rat model with femur condyle defect was employed,and TieMg MMCs implants were embedded into the femur *** showed that TieMg MMCs exhibited enhanced cytocompatibility to SaOS-2 cells than pure *** micro-computed tomography(Micro-CT)results showed that the volume of bone trabecula was significantly more abundant around TieMg implants than around Ti implants,indicating that more active new-bone formed around TieMg MMCs ***-eosin(H&E)staining analysis revealed significantly greater osteointegration around TieMg implants than that around Ti implants.

关键词： Powder metallurgy Composites Osteoconduction Osseointegration

Highly active electrocatalytic CO_(2) reduction with manganese N-heterocyclic carbene pincer by para electronic tuning

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Chinese Chemical Letters 2022年第1期33卷 262-265页

作者： Can Huang Jiahao Liu Hai-Hua Huang Xianfang Xu Zhuofeng Ke School of Materials science&Engineering School of ChemistryPCFM LabSun Yat-sen UniversityGuangzhou 510275China

Electronic tuning by para substitutions was explored to achieve a highly active manganese N-heterocyclic carbene pincer complex for the selective electrocatalytic reduction of CO_(2)to CO.[MnCNC^(OMe)]BF_(4)(L2-Mn)bearing an electron-donating group(-OMe)showed high activity with 63×catalytic current enhancement,average Faradaic efficiency of 104%,and a TOF_(max) value of 26,127 s^(-1),which is 127 times higher than that of unsubstituted[MnCNCH]Br(L1-Mn)reported *** contrast,the electron-withdrawing group(-COOMe)in[MnCNC^(CO^(OMe))]PF_(6)(L3-Mn)inhibited the electrocatalytic *** Brønstic acid,however,suppressed the activity of L2-Mn probably due to the protonation of the-OMe *** findings indicate a potential electronic tuning strategy to improved manganese N-heterocyclic carbene catalysts for CO_(2)reduction.

关键词： Pyridine N-heterocyclic carbene Electrocatalysis Carbon dioxide conversion Manganese Substituent effect

Clustering and scheduling methods based on SLNR in downlink CoMP system

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The Journal of china Universities of Posts and Telecommunications 2014年第1期21卷 74-78,103页

作者： WU Xu-guang LI Yi JI Hong School of Telecommunication Engineering Beijing University of Posts and Telecommunications

In downlink coordinated multi-point（CoMP） system, full cooperation is always not applicable in real world because of its high request in the backhaul. To deal with this problem, clustering decision is made to process transmission. In this paper clustering methods based on the metric signal-to-leakage-plus-noise（SLNR） is proposed. In addition, user scheduling schemes based on SLNR is also put up to make the scheduling set as large as possible. Simulation results show that the proposed clustering methods not only reduce the data sharing among the cooperating base stations（BSs）, but also improve the system throughput compared with the traditional clustering methods based on channel strength.

关键词： CoMP clustering formation SLNR user scheduling

Programmable double-unlock nanocomplex self-supplies phenylalanine ammonia-lyase for precise phenylalanine deprivation of tumors

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Chinese Chemical Letters 2024年第8期35卷 455-459页

作者： Chunqing Ou Meijia Xiao Xinyue Zheng Xianzhou Huang Suleixin Yang Yingying Leng Xiaowei Liu Xiuqi Liang Linjiang Song Yanjie You Shaohua Yao Changyang Gong Department of Biotherapy Cancer Center and State Key Laboratory of BiotherapyWest China HospitalSichuan UniversityChengdu 610041China State Key Laboratory of Quality Research in Chinese Medicine Institute of Chinese Medical SciencesUniversity of MacaoAvenida da UniversidadeTaipaMacao 999087China School of Medical and Life sciences Chengdu University of Traditional Chinese MedicineChengdu 611137China Department of Gastroenterology People’s Hospital of Ningxia Hui Autonomous RegionYinchuan 750002China

Essential amino acids(EAAs)deprivation is a potential antitumor approach because EAAs are critical for tumor *** efficiently inhibit tumor growth,continuous deprivation of EAAs is required,how-ever,continuous deprivation without precise control will introduce toxicity to normal ***,a programmable double-unlock nanocomplex(ROCK)was prepared,which could self-supply phenylalanine ammonia-lyase(PAL)to tumor cells for phenylalanine(Phe)*** was double-locked in physiological conditions when administered *** ROCK actively targeted to tumor cells by integrinαvβ3/5 and CD44,ROCK was firstly unlocked by cleavage of protease on tumor cell membrane,exposing CendR and R8 to enhance ***,hyaluronic acid was digested by hyaluronidase overexpressed in endo/lysosome of tumor cells,in which ROCK was secondly unlocked,resulting in pro-moting endo/lysosome escape and PAL plasmid(pPAL)*** pPAL could sustainably express PAL in host tumor cells until the self-supplied PAL precisely and successfully deprived Phe,thereby block-ing the protein synthesis and killing tumor cells ***,our precise Phe deprivation strategy effectively inhibited tumor growth with no observable toxicity to normal cells,providing new insights to efficiently remove intratumoral nutrition for cancer therapy.

关键词： Programmable double-unlock Essential amino acids deprivation Phenylalanine ammonia-lyase Self-supply Gene therapy

Origami meets electrospinning:a new strategy for 3D nanofiber scaffolds

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Bio-Design and Manufacturing 2018年第4期1卷 254-264页

作者： Juqing Song Guanglin Zhu Huichang Gao Lin Wang Nanying Li Xuetao Shi Yingjun Wang National Engineering Research Centre for Tissue Restoration and Reconstruction South China University of Technology Guangzhou 510006People's Republic of China Department of Biomedical Engineering School of Materials Science and EngineeringSouth China University of TechnologyGuangzhou 510006People's Republic of China School of Medicine South China University of TechnologyGuangzhou 510006People's Republic of China

Inspired by the constitution of things in the natural world,three-dimensional (3D)nanofiber scaffold/cells complex was constructed via the combination of electrospinning technology and origami *** nanofiber boxes prepared by origami provided a limited space for the layer-by-layer nanofiber films,and the human fetal osteoblasts (hFOBs)seeded on the both sides of the nanofiber films were expected to facilitate the bonding,of the adjacent nanofiber films through the secretion of extracellular ***,the hFOBs presented 3D distribution in the nanofiber scaffold,and they can stretch across the gaps between the adjacent nanofiber films,forming the cell layers and filling the whole 3D nanofiber ***,a 3D block composed of electrospun nanofiber scaffold and cells was obtained',which possesses potential applications in bone tissue ***,we also created 3D nanofiber structures that range from simple forms to intricate architectures via origami,indicating that the combination of electrospinning technology and origami techniques is a feasible method for the 3D construction of tissue engineering scaffolds.

关键词： Electrospinning Origami 3D construction Nanofiber scaffold/cells complex