检索结果-南通市图书馆

Reconfiguring wireless environments via intelligent surfaces for 6G: reflection, modulation, and security

Science China(Information Sciences) 2023年第3期66卷 60-79页

作者： Jindan XU Chau YUEN Chongwen HUANG Naveed ul hassan George C.ALEXANDROPOulOS Marco DI RENZO Mérouane DEBBAH Engineering Product Development Pillar Singapore University of Technology and Design College of Information Science and Electronic Engineering Zhejiang University Department of Electrical Engineering Lahore University of Management Sciences Department of Informatics and Telecommunications National and Kapodistrian University of Athens Technology Innovation Institute Université Paris-Saclay CNRS Centrale Supélec Laboratoire des Signaux et Systèmes

The reconfigurable intelligent surface(RIS) has been recognized as an essential enabling technology for sixth-generation(6G) mobile communication networks. An RIS comprises a large number of small and low-cost reflecting elements whose parameters can be dynamically adjusted with a programmable *** of these elements can effectively reflect a phase-shifted version of the incident electromagnetic wave. By configuring the wave phases in real time, the propagation environment of the information-bearing signals can be dynamically manipulated to enhance communication reliability, boost transmission rate, expand cellular coverage, and strengthen communication security. In this study, we provide an overview on RIS-assisted wireless communications. Specifically, we elaborate on the state-of-the-art enabling techniques for the RIS technology as well as their corresponding substantial benefits from the perspectives of RIS reflection and RIS modulation. With these benefits, we envision the integration of RISs into emerging applications for6G. In addition, communication security is of unprecedented importance in future 6G networks with ubiquitous wireless services in multifarious verticals and areas. We highlight potential contributions of RISs to physical-layer security, in terms of secrecy rate and secrecy outage probability, exemplified by a typical case study from both theoretical and numerical aspects. Finally, we discuss challenges and opportunities on the deployment of RISs in practice to motivate future research.

关键词： reconfigurable intelligent surface physical-layer security RIS-assisted wireless communications phase modulation 6G

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

One Dimensional Iron Molybdophosphate Anionic Chains with Different Structural Arrangements Reflecting a Flexibility Character

引用

Chemical Research in Chinese Universities 2013年第4期29卷 621-626页

作者： ZHOU Yun-shan hassan ul Sadaf LI Xian-qi ZHANG LI-juan AHMAD Waqar SHI Zong-hai State Key Laboratory of Chemical Resource Engineering Institute of Science Beij'ing University of Chemical Technology Beijing 100029 P. R. China

Structural comparison of a new compound [（bpp）3H6]Fe2ⅢFe2ⅡMo24Ⅴ（H2PO4）8（HPO4）4（PO4）4O48（OH）12·（H2O）4·2H2O（1）[bpp=1,3-di（4-pyridyl）propane] with our previously reported two compounds [（bpy）3FeⅡ]3·Fe2ⅢFe2ⅡMo24Ⅴ（H2PO4）8（HPO4）4（PO4）4O48（OH）12（H2O）4·12H2O（2） and [（bpy）3FeⅡ]2FeⅡFeⅢMo12Ⅴ（H2PO4）2（H2-xPO4）.（H1＋xPO4）（HPO4）2（PO4）2O24（OH）6（H2O）2·9H2O（x=0-1）（3）（bpy=2,2＇-bipyridine）,which all exhibit one-dimensional mixed-valence iron molybdophosphate anionic chains constructed by alternating connection of FeⅢ ions and magic [FeⅡ（Mo6P4O31）2] units,reveals that the non-hydrogen atomic ratios of Mo∶Fe∶P∶O within the polymeric anionic chains are the same for all the three compounds,while the polymeric anionic chains of the different compounds bear different numbers of negative *** therefore there exist different numbers of counter cations per {Fe2Ⅲ[Fe2Ⅱ（P16Mo24ⅤO124）]} unit found in the titled *** discloses that not only are the spatial assembling of counter cations and polymeric inorganic chains of three compounds quite different,but also the O-FeⅢ-O bond angles and FeⅢ-O bond lengths of the three different inorganic chains exhibit small *** is more important is that such small changes in bond length and bond angle in the assemblage of FeⅢ-O bonds lead to the considerable fluctuations of inorganic chains in their structural conformation within the three compounds,reflecting an interesting phenomenon of＂flexibility＂ in the pure inorganic one dimensional mixed-valence iron molybdophosphate chains.

关键词： Flexibility Conformation Crystal structure Inorganic chain Iron molybdophosphate

来源：

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

CNR:A Cluster-Based Solution for Connectivity Restoration for Mobile WSNs

引用

Computers, Materials & Continua 2021年第12期69卷 3413-3427页

作者： Mahmood ul hassan Amin Al-Awady Khalid Mahmood Shahzad Ali Ibrahim Algamdi Muhammad Kashif Saeed Safdar Zaman Department of Computer Skills Najran UniversityNajran66241Saudi Arabia Department of Information Systems College of Science and ArtsKing Khalid UniversityMahayil Asir63317Saudi Arabia Department of Computer Science Jouf UniversityTabarjal76769Saudi Arabia Department of Computer Science Community College Mahayil AsirKing Khalid UniversityMahayil63317Saudi Arabia Federal Directorate of Education Department of Computer ScienceIslamabad44000Pakistan

Wireless Sensor Networks(WSNs)are an integral part of the Internet of Things(IoT)and are widely used in a plethora of ***,sensor networks operate in harsh environments where human intervention is often restricted,which makes battery replacement for sensor nodes *** failure due to battery drainage or harsh environmental conditions poses serious challenges to the connectivity of the *** a connectivity restoration mechanism,node failures ultimately lead to a network partition,which affects the basic function of the sensor ***,the research community actively concentrates on addressing and solving the challenges associated with connectivity restoration in sensor *** energy is a scarce resource in sensor networks,it becomes the focus of research,and researchers strive to propose new solutions that are energy *** common issue that is well studied and considered is how to increase the network’s life span by solving the node failure problem and achieving efficient energy *** paper introduces a Clusterbased Node Recovery(CNR)connectivity restoration mechanism based on the concept of *** is a well-known mechanism in sensor networks,and it is known for its energy-efficient operation and *** proposed technique utilizes a distributed cluster-based approach to identify the failed nodes,while Cluster Heads(CHs)play a significant role in the restoration of *** simulations were conducted to evaluate the performance of the proposed technique and compare it with the existing *** simulation results show that the proposed technique efficiently addresses node failure and restores connectivity by moving fewer nodes than other existing connectivity restoration *** proposed mechanism also yields an improved field coverage as well as a lesser number of packets exchanged as compared to existing state-of-the-art mechanisms.

关键词： WSNs CHs CNR transmission range connectivity restoration node failure cluster communication range

来源：

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

Seed Priming Influence on Early Crop Growth, Phenological Development and Yield Performance of Linola (Linum usitatissimum L.)

引用

Journal of Integrative Agriculture 2014年第5期13卷 990-996页

作者： Hafeez ur Rehman Muhammad Qaiser Nawaz Shahzad Maqsood Ahmed Basra Irfan Afzal Azra Yasmeen Fayyaz ul-hassan Seed Physiology Laboratory Department of Crop Physiology University of Agriculture Faisalabad Soil Salinity Research Institute Pindi Bhatian College of Agriculture Bahuddin Zakriya University Department of Agronomy PMAS University of Arid Agriculture

Reduced early crop growth and limited branching are amongst yield limiting factors of linola. Field response of seed priming treatments viz. 50 mmol L^-1 salicylic acid （SA）, 2.2% CaCl2 and 3.3% moringa leaf extract （MLE） including untreated dry and hydropriming controls was evaluated on early crop growth and yield performance of linola. Osmopriming with CaCl2 reduced emergence time and produced the highest seedling fresh and dry weights including Chl. a contents. Osmopriming with CaCl2 reduced crop branching and flowering and maturity times and had the maximum plant height, number of branches, tillers, pods and seeds per pod followed by MLE. Increase in seed weight, biological and seed yields was 9.30, 34.16 and 39.49%, harvest index （4.12%） and oil contents （13.39%） for CaCl2 osmopriming. Positive relationship between emergence and seedling vigor traits, 100-seed weight, seed yield with maturity time, 100-seed weight and seed yield were found. The study concludes that seed osmopriming with CaC12 or MLE can play significant role to improve early crop growth and seed yields of linola.

关键词： linseed oil quality stand establishment CaCl2

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Development and challenges of green food in China

引用

Frontiers of Agricultural Science and Engineering 2020年第1期7卷 56-66页

作者： Mahmood ul hassan Xin WEN Jiuliang XU Jiahui ZHONG Xuexian LI Department of Plant Nutrition The Key Plant-Soil Interaction LaboratoryMinistry of EvironmentChina Agricultural UniversityBeijing 100193China National Academy of Agriculture Green Development China Agricultural UniversityBeijing 100193China Chinese Academy of Green Food Development Beijing 100193China

Green food in China refers to a wide array of primary and processed agricultural products that are safe,nutritious and of high quality for human *** food has been certified and produced following the principle of sustainability since the 1990 s,making historic achievements in providing quality food,protecting the environment,increasing farmer income,and nurturing agricultural brands over the past 30 years in ***,the green food industry enters a steady-growth stage in terms of cultivation area,product number and *** article summarizes the history of the development of green food in China and current achievements,analyze major challenges that may hamper further development of the industry,and propose strategies to address these challenges,i.e.,optimization of the food supply chain,deep food processing,and utilization of food wastes.

关键词： green food food losses storage processing transportation sustainability

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Signaling mechanisms mediated by G-protein coupled receptors in human platelets

引用

Acta Pharmacologica Sinica 2004年第7期25卷 41-46页

作者： Sheikh Arshad SAEED,Huma RASHEED,Faisal A Wahed FECTO,Mohammad Ilyas ACHAKZAI,Rahmat ALI,John Dennis CONNOR,Anwar-ul-hassan GILANI Department of Biological and Biomedical Sciences TheAga Khan University Karachi-74800 Pakistan Department of Biological and Biomedical Sciences TheAga Khan University Karachi-74800 Pakistan Department of Biological and Biomedical Sciences TheAga Khan University Karachi-74800 Pakistan Department of Biological and Biomedical Sciences TheAga Khan University Karachi-74800 Pakistan Department of Biological and Biomedical Sciences TheAga Khan University Karachi-74800 Pakistan Department of Biological and Biomedical Sciences TheAga Khan University Karachi-74800 Pakistan Department of Biological and Biomedical Sciences TheAga Khan University Karachi-74800 Pakistan

AIM: The present study deals with the investigation of mechanisms involved in the synergistic interaction between epinephrine and arachidonic acid (AA). METHODS: Venous blood was taken from healthy human volunteers reported to be free of medications for one week. Platelet aggregation was monitored at 37oC using Dual-channel Lumi-aggregometer. The resulting aggregation was recorded for 5 min by the measurement of light transmission as a function of time. RESulTS: The data show that a synergism in platelet aggregation mediated by subthreshold concentrations of epinephrine (1 μmol/L) and AA (0.2 μmol/L) was inhibited by the α2-receptor antagonist (yohimbine, IC50=0.6 μmol/L) and an inhibitor of AA-cyclooxygenase (COX), indomethacin (IC50=0.25 μmol/L). In examining receptor influence on intraplatelet signalling pathways, it was found that the synergistic effect was inhibited by calcium channel blockers, verapamil (IC50=0.4 μmol/L) and diltiazem (IC50=2.5 μmol/L), as well as by low concentrations of inhibitors of phospholipase C (PLC) (U73122; IC50=0.2 μmol/L) and mitogens activated protein kinase (MAPK) (PD 98059; IC50=3.8 μmol/L). Herbimycin A, a specific inhibitor of tyrosine light chain kinase (TLCK), showed inhibition at IC50 value of 15 μmol/L, whereas chelerythrine, a protein kinase C (PKC) inhibitor, had no effect up to 20 μmol/L. CONCLUSION: These data suggest that synergism between epinephrine and AA in platelet aggregation is triggered through receptors coupled to G-protein, which in turn, activate PLC, COX, and MAP kinase-signaling pathways.

关键词： platelet aggregation epinephrine arachidonic acid cyclooxygenase phospholipase C calcium channel blockers nitric oxide MAP kinase

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

不同流场下进气对质子交换膜燃料电池性能的影响

引用

工程热物理学报 2021年第2期42卷 413-417页

作者： Aezid-ul-hassan Najmi 刘智杜青焦魁天津大学内燃机国家重点实验室天津300350

流场的结构对于质子交换膜燃料电池(PEMFC)的水管理和气体的传递具有十分重要的影响,相关研究一直是燃料电池的研究热点与重点。本文以纯氧气和空气作为阴极氧化剂,通过电池的性能测试、极化曲线和电化学阻抗分析等原位实验,分析了气体... 详细信息

流场的结构对于质子交换膜燃料电池(PEMFC)的水管理和气体的传递具有十分重要的影响,相关研究一直是燃料电池的研究热点与重点。本文以纯氧气和空气作为阴极氧化剂,通过电池的性能测试、极化曲线和电化学阻抗分析等原位实验,分析了气体的流动与传输、不同流场下的电流密度、入口反应气体浓度等条件对电池性能的影响。实验结果表明,提高氧气浓度可以获得更好的质子交换膜燃料电池性能和最小化活化损失,纯氧气、波状流场的使用效果随进气量的变化而有明显的变化。

关键词：质子交换膜燃料电池(PEMFC) 波状流场原位实验进气

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Gut microbiome colonization and development in neonatal ruminants: Strategies, prospects, and opportunities

引用

Animal Nutrition 2021年第3期7卷 883-895页

作者： Muhammad A.Arshad Faiz-ul hassan Muhammad S.Rehman Sharon A.Huws Yanfen Cheng Ahmad U.Din Institute of Animal and Dairy Sciences Faculty of Animal HusbandryUniversity of AgricultureFaisalabad38040Pakistan Laboratory of Gastrointestinal Microbiology National Center for International Research on Animal Gut NutritionNanjing Agricultural UniversityNanjing210095China Key Laboratory of Buffalo Genetics Breeding and Reproduction TechnologyMinistry of Agriculture and Guangxi Buffalo Research InstituteChinese Academy of Agricultural SciencesNanning530001China School of Biological Sciences Institute for Global Food SecurityQueen's University of BelfastBelfastBT95DLGB-NIRUK Drug Discovery Research Center Southwest Medical UniversityLuzhou646000China

Colonization and development of the gut microbiome is a crucial consideration for optimizing the health and performance of livestock animals. This is mainly attributed to the fact that dietary and management practices greatly influence the gut microbiota, subsequently leading to changes in nutrient utilization and immune response. A favorable microbiome can be implanted through dietary or management in-terventions of livestock animals, especially during early life. In this review, we explore all the possible factors (for example gestation, colostrum, and milk feeding, drinking water, starter feed, inoculation from healthy animals, prebiotics/probiotics, weaning time, essential oil and transgenesis), which can influence rumen microbiome colonization and development. We discuss the advantages and disadvantages of potential strategies used to manipulate gut development and microbial colonization to improve the production and health of newborn calves at an early age when they are most susceptible to enteric disease. Moreover, we provide insights into possible interventions and their potential effects on rumen development and microbiota establishment. Prospects of latest techniques like transgenesis and host genetics have also been discussed regarding their potential role in modulation of rumen microbiome and subsequent effects on gut development and performance in neonatal ruminants.

关键词： Gut development Microbial colonization Rumen microbiota Health Performance

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

An Efficient Connectivity Restoration Technique(ECRT)for Wireless Sensor Network

引用

Computers, Materials & Continua 2021年第10期69卷 1003-1019页

作者： Mahmood ul hassan Shahzad Ali Khalid Mahmood Muhammad Kashif Saeed Amin Al-Awady Kamran Javed Ansar Munir Shah Department of Computer Skills Preparatory yearNajran UniversityNajran66241Saudi Arabia Department of Computer Science Jouf UniversityTubarjal74769Saudi Arabia Department of Information Systems College of Science and ArtsKing Khalid UniversityMahayil Asir63317Saudi Arabia Department of Computer Science Community College Mahayil AsirKing Khalid UniversityMahayil63718Saudi Arabia Department of Computer Engineering National University of Technology(NUTECH)Islamabad44000Pakistan Department of Computer Science Institute of Southern PunjabMultan60000Pakistan

Node failure in Wireless Sensor Networks(WSNs)is a fundamental problem because WSNs operate in hostile *** failure of nodes leads to network partitioning that may compromise the basic operation of the sensor *** deal with such situations,a rapid recovery mechanism is required for restoring inter-node *** to the immense importance and need for a recovery mechanism,several different approaches are proposed in the ***,the proposed approaches have shortcomings because they do not focus on energy-efficient operation and coverage-aware mechanisms while performing connectivity ***,most of these approaches rely on the excessive mobility of nodes for restoration connectivity that affects both coverage and energy *** paper proposes a novel technique called ECRT(Efficient Connectivity Restoration Technique).This technique is capable of restoring connectivity due to single and multiple node *** achieves energy efficiency by transmitting a minimal number of control *** is also coverage-aware as it relocates minimal nodes while trying to restore *** the help of extensive simulations,it is proven that ECRT is effective in connectivity restoration for single and multiple node *** also show that ECRT exchanges a much smaller number of packets than other ***,it also yields the least reduction in field coverage,proving its versatility for connectivity restoration.

关键词： Cut-vertex failure recovery network connectivity node relocation wireless sensor network node failures

来源：

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

Improved-Equalized Cluster Head Election Routing Protocol for Wireless Sensor Networks

引用

Computer Systems Science & Engineering 2023年第1期44卷 845-858页

作者： Muhammad Shahzeb Ali Ali Alqahtani Ansar Munir Shah Adel Rajab Mahmood ul hassan Asadullah Shaikh Khairan Rajab Basit Shahzad Department of Computer Science Institute of Southern PunjabMultan5932Pakistan College of Computer Science and Information Systems Najran UniversityNajran61441Saudi Arabia Department of Computer Skills Deanship of Preparatory YearNajran UniversityNajran61441Saudi Arabia Department of Engineering National University of Modern LanguagesIslamabad44000Pakistan

Throughout the use of the small battery-operated sensor nodes encou-rage us to develop an energy-efficient routing protocol for wireless sensor networks(WSNs).The development of an energy-efficient routing protocol is a mainly adopted technique to enhance the lifetime of *** routing protocols are available,but the issue is still *** is one of the most important techniques in the existing routing *** the clustering-based model,the important thing is the selection of the cluster *** this paper,we have proposed a scheme that uses the bubble sort algorithm for cluster head selection by considering the remaining energy and the distance of the nodes in each ***,the bubble sort algorithm chose the two nodes with the maximum remaining energy in the cluster and chose a cluster head with a small *** proposed scheme performs hierarchal routing and direct routing with some energy *** simulation will be performed in MATLAB to justify its performance and results and compared with the ECHERP model to justify its ***,the simulations will be performed in two scenarios,gate-way-based and without gateway to achieve more energy-efficient results.

关键词： Bubble sort algorithm gateway energy thresholds wireless sensor networks

来源：

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

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：