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The Journal of China Universities of Posts and Telecommunications 2011年第3期18卷 1-7页

作者： CHEN dan JI Hong li xi College of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing 100876 China

Cooperative relaying is emerging as an effective technology to fulfill requirements on high data rate coverage in next-generation cellular networks, like long term evolution-advanced （LTE-Advanced）. In this paper, we propose a distributed joint relay node （RN） selection and power allocation scheme over multihop relaying cellular networks toward LTE-Advanced, taking both the wireless channel state and RNs＇ residual energy into consideration. We formulate the multihop relaying cellular network as a restless bandit system. The first-order finite-state Markov chain is used to characterize the time-varying channel and residual energy state transitions. With this stochastic optimization formulation, the optimal policy has indexability property that dramatically reduces the computational complexity. Simulation results demonstrate that the proposed scheme can efficiently enhance the expected system reward, compared with other existing algorithms.

关键词： cooperative relaying LTE-Advanced relay selection power allocation residual energy restless bandit

Optimal joint relay selection and resource allocation with QoS constraints in multiuser OFDM-based cellular networks

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High Technology Letters 2011年第3期17卷 305-310页

作者： Chen dan Ji Hong li xi Luo Changqing Beijing University of Posts and Telecommunications Beijing 100876 P. R. China

This paper investigates the relay selection and resource allocation problem in multiuser orthogonal frequency division multiplexing （OFDM） based cooperative cellular networks, in which user nodes could relay information for each other using the decode-and-forward （DF） protocol to achieve spatial diversity gain. Specifically, the paper proposes an optimal joint relay selection and resource allocation （0RSRA） algorithm whose objective is to maximize system total achievable data rate with the constraints of each user＇ s individual quality of service （QoS） requirement and transmission power. Due to being a mixed binary integer programming （MBIP） problem, a novel two-level Lagrangian dual-primal decomposition and subgradient projection approach is proposed to not only select the appropriate cooperative relay nodes, but also allocate subcarries and power optimally. Simulation re- suits demonstrate that our proposed scheme can efficiently enhance overall system data rate and guarantee each user＇ s QoS requirement. Meanwhile, the fairness among users can be improved dramatically.

关键词： cooperative diversity relay selection resource allocation Lagrangian dual-primal decomposition

Control of Bromate and THM Precursors Using Ozonation Combined System

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Biomedical and Environmental Sciences 2007年第3期20卷 217-225页

作者： SHU-GUANG xiE DONG-WEN SHI DONG-HUI WEN RUI WANG dan-li xi Department of Environmental Sciences College of Environmental Sciences Peking University Beijing 100871 China School of Environmental Sciences and Engineering Donghua University Shanghai 200051 China Zhenzhou Water Supply Corp. Zhengzhou 450013 Henan China

Objective To investigate the feasibility of reducing THM precursors and controlling bromate taste and odor in drinking water taken from the Yellow River by an ozonation combined system. Methods The appropriate ozone dosage was determined, and then the changes of TOC, UV254 and THM formation potential （THMFP） in the combined system were evaluated. Results One mg/L ozone could effectively remove taste and odor and meet the maximum allowable bromate level in drinking water. The pre-ozonation increased THMFP, but the conventional treatment system could effectively reduce the odor. The bio-ceramic filter could partly reduce CHC13FP, but sometimes might increase CHCl2BrFP and CHClBr2FP. The biological activated carbon （BAC） filter could effectively reduce CHC13FP and CHCl2BrFP, but increase CHClBr2FP. Compared with other filters, the fresh activated carbon （FAC） filter performed better in reducing THMFP and even reduced CHClBr2FP. Conclusion The combined system can effectively reduce taste, odor, CHC13FP, and CHCl2BrFP and also bring bromate under control.

关键词： Bromate Ozonation Disinfection by-products Activated carbon

QoS-guaranteed multi-relay selection and power allocation optimization in cooperative systems

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The Journal of China Universities of Posts and Telecommunications 2010年第6期17卷 25-31页

作者： CHEN dan,JI Hong,li xi,li Yi College of Information and Communication Engineering,Beijing University of Posts and Telecommunications,Beijing 100876,China College of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing 100876 China

This paper investigates the relay selection and power allocation problem in multi-user based cooperative networks,where intermediate relay nodes help source forward information to destination using decode-and-forward （DF） relaying protocol. Specifically,we propose a novel multi-relay nodes selection strategy taking both instantaneous channel state information （I-CSI） and residual energy into consideration,by which ＇emergence＇ diversity gain can be achieved and the imbalance of resource utilization can be overcome. Besides,using Largangian dual-primal decomposition and subgradient projection approach,an optimal power allocation algorithm at source and cooperative relay nodes is presented with the constraints of each user＇s individual quality of service （QoS） requirements and system total transmit power. Theoretical analysis and simulation results demonstrate that the proposed scheme can significantly improve energy efficiency,while guaranteeing a good balance between achievable data rate and average network lifetime with relatively low implementation complexity.

关键词： cooperative diversity relay selection resource allocation Lagrangian dual-primal decomposition subgradient projection

Mutation in the Agrobacterium his I gene enhances transient expression in pepper

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Horticultural Plant Journal 2024年第3期10卷 809-822页

作者： dan liu Shengnan Zhao Jubin Wang xi Zhang Yingtian Deng Feng li National Key Laboratory for Germplasm Innovation&Utilization of Horticultural Crops College of Horticulture and Forestry SciencesHuazhong Agricultural UniversityWuhanHubei 430070China

Agrobacterium-mediated plant transformation is widely used in plant genetic ***,its efficiency is limited by plant immunity against *** pepper(Capsicum annuum L.)is an important vegetable that is recalcitrant to Agrobacterium-mediated *** this work,Agrobacterium was found to induce a strong immune response in pepper,which might be the reason for T-DNA being difficult to express in *** Agrobacterium mutant screen was conducted and a point mutation in the hisI gene was identified due to a weak immune response and enhanced transient expression mediated by this Agrobacterium mutant in pepper *** genetic analysis revealed that histidine biosynthesis deficiency caused by mutations in many genes of this pathway led to reduced pepper cell death,presumably due to reduced bacterial ***,mutation analysis of threonine and tryptophan biosynthesis genes showed that the biosynthesis of different amino acids may play different roles in Agrobacterium growth and stimulating the pepper immune *** possible application of Agrobacterium amino acid biosynthesis mutations in plant biology was discussed.

关键词： Capsicum annuum L. Agrobacterium Transient transformation efficiency Mutation Amino acid Immune response

Low-molecular-weight heparin and preeclampsia—does the sword cut both ways?Three case reports and review of literature

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World Journal of Clinical Cases 2024年第9期12卷 1634-1643页

作者： dan Shan Tao li xi Tan Ya-Yi Hu Department of Obstetrics and Gynecology West China Second University HospitalSichuan UniversityChengdu 610000Sichuan ProvinceChina Key Laboratory of Birth Defects and Related Diseases of Women and Children Sichuan UniversityMinistry of EducationChengdu 610000SichuanChina

BACKGROUND Low-molecular-weight heparins(LMWH)are the most commonly used anticoagulants during *** is considered to be the drug of choice due to its safety in not crossing *** the beneficial effect in the improvement of microcirculation,prophylactic application of LMWH in patients with preeclampsia became a ***,the bleeding risk related with LMWH in preeclampsia patients has seldomly been *** current study aimed to identify the potential risks regarding LMWH application in patients with *** SUMMARY Herein we present a case series of three pregnant women diagnosed with preeclampsia on LMWH therapy during *** the cases experienced catastrophic hemorrhagic *** reviewing the twenty-one meta-analyses,the bleeding risk related with LMWH seems *** one study analyzed the bleeding risk of LMWH and found a significantly higher risk of developing PPH in women receiving *** studies reported minor bleeding risks,none of these were serious enough to stop LMWH *** of bleeding either from uterus or from intrabdominal organs in preeclampsia patients on LMWH therapy should not be *** management of blood pressure even after delivery and homeostasis suture in surgery are *** Consideration should be given to the balance between benefits and risks of LMWH in patients with preeclampsia.

关键词： Pregnancy Preeclampsia Low-molecular-weight heparin Hemorrhage Case report

Three-dimensional cell-based strategies for liver regeneration

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BIOCELL 2024年第7期48卷 1023-1036页

作者： dan GUO xi xiA JIAN YANG liver Transplant Center Transplant CenterWest China HospitalSichuan UniversityChengdu610041China Frontiers Medical Center Tianfu Jincheng LaboratoryChengdu610212China

liver regeneration and the development of effective therapies for liver failure remain formidable challenges in modern *** recent years,the utilization of 3D cell-based strategies has emerged as a promising approach for addressing these urgent clinical *** review provides a thorough analysis of the application of 3D cell-based approaches to liver regeneration and their potential impact on patients with end-stage liver ***,we discuss various 3D culture models that incorporate hepatocytes and stem cells to restore liver function and ameliorate the consequences of liver ***,we explored the challenges in transitioning these innovative strategies from preclinical studies to clinical *** collective insights presented herein highlight the signiﬁcance of 3D cell-based strategies as a transformative paradigm for liver regeneration and improved patient care.

关键词： Three-Dimensional liver regeneration Organoids Stem cells Cell therapy

An extended numerical model of the first exothermic peak for three dimensional printed cement-based materials

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Frontiers of Structural and Civil Engineering 2024年第1期18卷 80-88页

作者： Wei JIANG Wenqian li xi CHEN School of Materials Science and Engineering Tongji UniversityShanghai 200092China School of Civil Engineering Tongji UniversityShanghai 200092China

The first exothermic peak of cement-based material occurs a few minutes after mixing,and the properties of three dimensional(3D)printed concrete,such as setting time,are very sensitive to *** this background,based on the classical Park cement exothermic model of hydration,we propose and construct a numerical model of the first exothermic peak,taking into account the proportions of C_(3)S,C_(3)A and quicklime in *** calculated parameters are calibrated by means of relevant published exothermic test *** is found that this developed model offers a good simulation of the first exothermic peak of hydration for C_(3)S and C_(3)A proportions from 0 to 100% of cement clinker and reflects the effect of quicklime content at 8%-10%.The unique value of this research is provision of an important computational tool for applications that are sensitive to the first exothermic peak of hydration,such as 3D printing.

关键词： 3D printed cement-based materials cement hydration the first exothermic peak liquid quick-setting agent numerical model

A new method to solve the Reynolds equation including mass-conserving cavitation by physics informed neural networks(PINNs)with both soft and hard constraints

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Friction 2024年第6期12卷 1165-1175页

作者： Yinhu xi Jinhui DENG Yiling li School of Mechanical Engineering Anhui University of Science and TechnologyHuainan 232001China Ericsson AB Datalinjen 3Linköping 58330Sweden

In this work,a new method to solve the Reynolds equation including mass-conserving cavitation by using the physics informed neural networks(PINNs)is *** complementarity relationship between the pressure and the void fraction is *** are several difficulties in problem solving,and the solutions are ***,the difficulty for considering the pressure inequality constraint by PINNs is solved by transferring it into one equality constraint without introducing *** the void fraction inequality constraint is considered by using the hard constraint with the max-min ***,to avoid the fluctuation of the boundary value problems,the hard constraint method is also utilized to apply the boundary pressure values and the corresponding functions are ***,for avoiding the trivial solution the limitation for the mean value of the void fraction is *** results are validated against existing data,and both the incompressible and compressible lubricant are *** agreement can be found for both the domain and domain boundaries.

关键词： Reynolds equation mass-conserving cavitation physics informed neural networks hard constraints trivial solution

Genesis of ultra-deep dolostone and controlling factors of largescale reservoir:A case study of the Sinian Dengying Formation and the Cambrian Longwangmiao Formation in the Sichuan Basin

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Science China Earth Sciences 2024年第7期67卷 2352-2382页

作者： xi li Guangyou ZHU Zhiyao ZHANG PetroChina Research Institute of Petroleum Exploration and Development Beijing 100083China School of Geosciences Yangtze UniversityWuhan 430100China School of Earth Resoures China University of GeosciencesWuhan 430074China

This paper investigates the origin of ultra-deep dolostone and the factors influencing large-scale dolostone reservoirs,focusing on the Sinian Dengying Formation and the Cambrian Longwangmiao Formation in the Sichuan *** study involves petrology,microscale X-ray diffraction,trace element analysis,and C-O-Sr-Mg isotope experiments to provide a detailed *** research findings indicate that the Dengying and Longwangmiao formations comprise six types of matrix dolostone and four types of *** Dengying Formation,which developed under a sedimentary background of a restricted platform,contains special microbial and microcrystalline *** dolomite grains are small(line,and calcite dolostones with coarser and more ordered crystals exhibit similar δ^(13)C and^(87)Sr/^(86)Sr values to microbial and microcrystalline *** the sedimentary period of the Dengying Formation,ancient marine conditions were favorable for microbial *** induced the direct precipitation of primary dolomite in seawater,forming microbial and microcrystalline dolostones during the seawater diagenesis *** the subsequent diagenesis period,dolostones underwent the effects of dissolution-recrystallization,structures,and hydrothermal *** resulted in the formation of dolostone with coarser crystals,a higher degree of order,and various types of *** Longwangmiao Formation was developed in an interplatform beach characterized by special particle *** particle dolostone has a large grain size(>30μm),high order degree(Min=0.7),small unit cell parameters,high Na content

关键词： Ultra-deep layers Dolostone Supercontinent evolution Microscale geochemistry Dengying Formation Longwangmiao Formation Sichuan Basin