检索结果-南通市图书馆

Low-permittivity LiLn(PO_(3))_(4)(Ln=La,sm,Eu)dielectric ceramics for microwave/millimeter-wave communication

Journal of Advanced Ceramics 2024年第5期13卷 602-620页

作者： Huanrong Tian Xiaohan zhang Zidong zhang Yao Liu Haitao wu Key Laboratory for Liquid-solid structural Evolution and Processing of Materials(Ministry of Education) Shandong UniversityJinan 250061China school of Materials science and Engineering Shandong UniversityJinan 250061China school of Environmental and Material Engineering Yantai UniversityYantai 264005China

The development of dielectric materials with low permittivity and low loss is a great challenge in wireless *** this study,LiLn(PO_(3))_(4)(Ln=La,sm,Eu)ceramic systems were successfully prepared using the traditional solid-state method.X-ray diffraction analysis indicated that the LiLn(PO_(3))_(4)ceramics crystallized in a monoclinic structure when sintered at 850–940℃.The characteristic peak shifted to higher angles with variations in the Ln element,which was ascribed to a reduction in the cell *** analysis by structure refinement revealed that the reduction in the cell volume resulted from the decrease in chemical bond lengths and the compression of[LiO_(4)]and[PO_(4)]***,the LiLn(PO_(3))_(4)ceramic system displayed exceptional performance at low sintering temperatures(910–925℃),including a high quality factor(Q·f)of 41,607–75,968 GHz,low temperature coefficient of resonant frequency(τ_(f))ranging from−19.64 to−47.49 ppm/℃,low permittivity(ε_(r))between 5.04 and 5.26,and low density(3.04–3.26 g/cm^(3)).The application of Phillips–van Vechten–Levine(P–V–L)theory revealed that the increased Q·f value of the LiLn(PO_(3))_(4)systems can be attributed to the enhanced packing fraction,bond covalency,and lattice energy,and the stability of τ_(f) was associated with the increase in the bond ***,a prototype microstrip patch antenna using LiEu(PO_(3))_(4) ceramics was *** measurement results demonstrated excellent antenna performance with a bandwidth of 360 MHz and a peak gain of 5.11 dB at a central frequency of 5.08 ***,low-εr LiLn(PO_(3))_(4)ceramic systems are promising candidates for microwave/millimeter-wave communication.

关键词： low permittivity LiLn(PO_(3))_(4) microwave dielectric properties Phillips-van Vechten-Levine(P-V-L)theory microstrip patch antenna

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

Recent advances in electrochemical performance of Mg-based electrochemical energy storage materials in supercapacitors:Enhancement and mechanism

引用

Journal of Magnesium and Alloys 2024年第1期12卷 35-58页

作者： Yuntao Xiao Xinfang zhang Can wang Jinsong Rao Yuxin zhang College of Materials science and Engineering Chongqing UniversityChongqing 400044China

The application of Mg-based electrochemical energy storage materials in high performance supercapacitors is an essential step to promote the exploitation and utilization of magnesium resources in the field of energy ***,the inherent chemical properties of magnesium lead to poor cycling stability and electrochemical reactivity,which seriously limit the application of Mg-based materials in ***,in this review,more than 70 research papers published in recent 10 years were collected and *** representative research works were selected,and the results of various regulative strategies to improve the electrochemical performance of Mg-based materials were *** effects of various regulative strategies(such as constructing nanostructures,synthesizing composites,defect engineering,and binder-free synthesis,etc.)on the electrochemical performance and their mechanism are demonstrated using spinelstructured MgX_(2)O_(4) and layered structured Mg-X-LDHs as *** addition,the application of magnesium oxide and magnesium hydroxide in electrode materials,MXene's solid spacers and hard templates are ***,the challenges and outlooks of Mg-based electrochemical energy storage materials in high performance supercapacitors are also discussed.

关键词： supercapacitor Electrochemical energy storage Mg-based materials

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

The influence of stress-dependent overpotential on dendrite growth in all-solid-state battery with cracks

引用

science China Technological sciences 2024年第8期67卷 2493-2504页

作者： zhang ZhenHua zhang Yong LIU Chang HOU Xu wANG Jie Department of Engineering Mechanics School of Aeronautics and Astronautics Zhejiang University school of Aerospace Engineering and Applied Mechanics Tongji University Applied Mechanics and structure safety Key Laboratory of sichuan Province School of Mechanics and Aerospace Engineering Southwest Jiaotong University Department of Industrial and systems Engineering The Hong Kong Polytechnic University Zhejiang Laboratory Key Laboratory of soft Machines and smart Devices of Zhejiang Province Zhejiang University

Dendrite growth is one of the main challenges in maintaining the service life of all-solid-state lithium-ion batteries. Mechanical stress has been reported to significantly affect dendrite growth. In this study, to explain the effect of mechanical stress on electrochemical reactions in all-solid-state batteries, a modified phase-field model for dendrite growth is proposed by considering the stress-dependent overpotential. Dendrite growth under different mechanical loadings in an all-solid-state battery is investigated using the proposed model. Consistent with previous experimental results, the current result shows that compressive stress inhibits dendrite growth. Considering the stress concentration at the tips of processing-induced microcracks, the effects of the number and distribution of microcracks on dendrite growth are investigated. The results show that the stress-concentration field induced at the tips of cracks or voids can change the morphology of dendrites and decrease their growth rates. This study provides a new perspective for explaining Li dendrite growth under mechanical stress and offers inspiration for prolonging the service life of all-solid-state batteries based on defect and stress regulation, which may be further realized in experiments by filling solid electrolytes with different types of nanofillers.

关键词： Butler–Volmer equation stress-dependent overpotential microcracks all-solid-state battery phase-field simulation

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

Discovery of the choristodere Hyphalosaurus baitaigouensis from the Lower Cretaceous Jiufotang Formation of western Liaoning,China and its paleobiogeographic significance

引用

Journal of Palaeogeography 2024年第3期13卷 547-562页

作者： Li-Jun zhang shu-An Ji Hai-Chun zhang south China sea Culture Museum Hainan Tropical Ocean UniversitySanya 572022Hainan ProvinceChina Key Laboratory of stratigraphy and Paleontology Ministry of Natural ResourcesInstitute of GeologyChinese Academy of Geological SciencesBeijing 100037China state Key Laboratory of Palaeobiology and stratigraphy Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and PaleoenvironmentChinese Academy of SciencesNanjing 210008Jiangsu ProvinceChina

The water-living reptile genus Hyphalosaurus was previously discovered in the Lower Cretaceous Yixian Formation bearing the middle Jehol Biota in western Liaoning,*** complete skeletons of Hyphalosaurus are reported for the first time from the Jiufotang Formation bearing the late Jehol Biota at two sites in western *** show the typical characteristics of Hyphalosaurus baitaigouensis in terms of the contact between some cranial bones and the number of cervical and dorsal vertebrae,and therefore are assigned to *** discovery extends the stratigraphic range of this species from the Yixian Formation to the overlying Jiufotang *** paper further briefly compares the main characteristics of the two skeletons,summarizes the temporal and spatial distribution of Hyphalosaurus,and discusses the palaeogeographic evolution of western Liaoning at the middle and late Jehol Biota stages based on the aquatic habits of Hyphalosaurus and the geological background of western *** analytical results show that the volcanic downwarped lakes,with distinct geographical divisions in western Liaoning during the deposition of the Yixian Formation,had not completely disappeared till the deposition of the Jiufotang *** palaeo-lake in the Fuxin-Yixian Basin underwent the process of generation,expansion and shrinkage during the depositional period of the Yixian Formation and finally merged into a large *** palaeo-Dalinghe River,which connected the main basins in western Liaoning during the depositional period of the Jiufotang Formation,was formed simultaneously.

关键词： western liaoning Jehol biota Jiufotang formation Hyphalosaurus baitaigouensis Palaeobiogeography

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

Comprehensive Relation Modelling for Image Paragraph Generation

引用

Machine Intelligence Research 2024年第2期21卷 369-382页

作者： Xianglu Zhu zhang zhang wei wang Zilei wang Automation Department University of Science and Technology of ChinaHefei 230027China Center for Research on Intelligent Perception and Computing National Laboratory of Pattern RecognitionInstitute of AutomationChinese Academy of SciencesBeijing 100190China University of Chinese Academy of sciences Beijing 100864China

Image paragraph generation aims to generate a long description composed of multiple sentences,which is different from traditional image captioning containing only one *** of previous methods are dedicated to extracting rich features from image regions,and ignore modelling the visual *** this paper,we propose a novel method to generate a paragraph by modelling visual relationships ***,we parse an image into a scene graph,where each node represents a specific object and each edge denotes the relationship between two ***,we enrich the object features by implicitly encoding visual relationships through a graph convolutional network(GCN).we further explore high-order relations between different relation features using another graph convolutional *** addition,we obtain the linguistic features by projecting the predicted object labels and their relationships into a semantic embedding *** these features,we present an attention-based topic generation network to select relevant features and produce a set of topic vectors,which are then utilized to generate multiple *** evaluate the proposed method on the stanford image-paragraph dataset which is currently the only available dataset for image paragraph generation,and our method achieves competitive performance in comparison with other state-of-the-art(sOTA)methods.

关键词： Image paragraph generation visual relationship scene graph graph convolutional network(GCN) long short-term memory

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

Global stability of a Viral Infection Model with Defectively Infected Cells and Latent Age

引用

Chinese Annals of Mathematics,series B 2024年第4期45卷 555-572页

作者： Jianquan LI Yuming CHEN Peijun zhang Dian zhang school of Computer science Xijing University Department of Mathematics Wilfrid Laurier University Xi'an Key Laboratory of Human-Machine Integration and Control Technology for Intelligent Rehabilitation Xijing University Equal contributor.Department of Immunology Xi'an Medical University

The authors propose and analyze a viral infection model with defectively infected cells and age of the latently infected cells. The existence of steady states is determined by the basic reproduction number of virus. with the Lyapunov's direct method, they establish a threshold dynamics of the model with the basic reproduction number of virus as the threshold parameter. To achieve it, a novel procedure is proposed. Its novelties are two-folded. On one hand, the coefficients involved in the specific forms of the used Lyapunov functionals for the two feasible steady states are determined by the same set of inequalities. On the other hand, for the infection steady state, a new approach is proposed to check whether the derivative of the Lyapunov functional candidate along solutions is negative(semi-)definite or not. This procedure not only simplifies the analysis but also exhibits the relationship between the two Lyapunov functionals for the two feasible steady states. Moreover, the procedure is expected to be applicable for other similar models.

关键词： Age structure Basic reproduction number Equilibrium Global stability Lyapunov direct method Viral infection model

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

Microbiome and intestinal pathophysiology in post-acute sequelae of COVID-19

引用

Genes & Diseases 2024年第3期11卷 220-231页

作者： Jilei zhang Yongguo zhang Yinglin Xia Jun sun Division of Gastroenterology and Hepatology Department of MedicineUniversity of Ilinois ChicagoIL60612USA Uic Cancer Center Department of Microbiology and ImmunologyUniversity of Ilinois ChicagoChicagoIL60612USA Jesse Brown VA Medical Center ChicagoIL60612USA

Long CoVID,also known for post-acute sequelae of CovID-19,describes the people who have the signs and symptoms that continue or develop after the acute coviD-19 *** CovID patients suffer from an inflammation or host responses towards the virus approx-imately 4 weeks after initial infection with the sARs CoV-2 virus and continue for an unchar-acterized *** infected with CovID-19 before could experience long-CcovID conditions,including the patients who were infected with sARs CoV-2 virus confirmed by tests and those who never knew they had an infection *** with long CoviD may experience health problems from different types and combinations of symptoms over time,such as fa-tigue,dyspnea,cognitive impairments,and gastrointestinal(Gl)symptoms(e.g.,nausea,vom-iting,diarrhea,decreased or loss of appetite,abdominal pain,and dysgeusia).The critical role of the microbiome in these Gl symptoms and long CovID were reported in clinical patients and experimental ***,we provide an overall view of the critical role of the Gl tract and microbiome in the development of long COVID,including the clinical Gl symptoms in patients,dysbiosis,viral-microbiome interactions,barrier function,and inflammatory bowel disease patients with long *** highlight the potential mechanisms and possible treatment based on Gl health and ***,we discuss challenges and future direction in the long CoVID clinic and research.

关键词： Gastrointestinal symptoms Gl tract Gut microbiome Inflammatorybowel diseases Intestinal barrier Long CoVID Metabolites Tight junctions

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

Effect of the anionic composition of sulfolane based electrolytes on the performances of lithium-sulfur batteries

引用

Journal of Energy Chemistry 2024年第8期95卷 231-240,I0005页

作者： Elena V.Karaseva Elena V.Kuzmina Bo-Quan Li Qiang zhang Vladimir s.Kolosnitsyn Ufa Institute of Chemistry of the Ufa Federal Research Centre of the Russian Academy of science 71Prospect OktyabryaUfa 450054BashkortostanRussia Advanced Research Institute of Multidisciplinary science Beijing Institute of TechnologyBeijing 100081China Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology Department of Chemical EngineeringTsinghua UniversityBeijing 100084China

In lithium-sulfur batteries,cell design,specifically electrolyte design,has a key impact on the battery *** effect of lithium salt anion donor number(DN)(DN[PF_(6)]^(-)=2.5,DN[N(sO_(2)CF_(3))_(2)]^(-)=5.4,DN[ClO_(4)]^(-)=8.4,DN[sO_(3)CF_(3)]^(-)=16.9,and DN[NO_(3)]^(-)=21.1)on the patterns of lithium-sulfur batteries and lithium metal electrode performances with sulfola ne-based electrolytes is *** increase in DN of lithium salt anions leads to an increase in the depth and rate of electrochemical reduction of sulfur and long-chain lithium polysulfides and to a decrease in those for medium-and short-chain lithium *** of lithium salt anions has weak effect on the discharge capacity of lithium-sulfur batteries and the Coulomb efficiency during cycling,with the exception of LisO_(3)CF_(3)and LiNO_(3).An increase in DN of lithium salt anions leads to an increase in the cycling duration of lithium metal anodes and to a decrease in the presence of lithium *** sulfolane solutions of LiNO_(3)and LisO_(3)CF_(3),lithium polysulfides do not affect the cycling duration of lithium metal anodes.

关键词： Donor number Lithium salt sulfolane Lithium polysulfide Electrolyte Lithium-sulfur battery Lithium metal electrode

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

Potential of arbuscular mycorrhizal fungi for soil health:A review

引用

Pedosphere 2024年第2期34卷 279-288页

作者： Junling zhang Ruotong ZHAO Xia LI Jiangzhou zhang College of Resources and Environmental sciences National Academy of Agriculture Green DevelopmentKey Laboratory of Plant-Soil InteractionsMinistry of EducationChina Agricultural UniversityBeijing 100193China College of Agronomy and Life science Shanxi Datong UniversityDatong 037009China College of Resources and Environment/International Magnesium Institute Fujian Agriculture and Forestry UniversityFuzhou 350002China

soil health is an important component of“One Health”.soils provide habitat to diverse and abundant *** microbial diversity and functions is essential for building healthy soils towards sustainable *** mycorrhizal fungi(AMF)form potentially symbiotic associations with approximately 80%of land plant species that are well recognized for carbon flux and nutrient *** addition to disentangling the signaling pathways and regulatory mechanisms between the two partners,recent advances in hyphosphere research highlight some emerging roles of AMF and associated microbes in the delivery of soil *** paper reviews the contribution of AMF to soil health in agroecosystems,with a major focus on recent progress in the contribution of hyphosphere microbiome to nutrient cycling,carbon sequestration,and soil *** hyphosphere microbiome and fungal stimulants open avenues for developing new fertilizer formulas to promote AMF *** practice,developing AMF-friendly management strategies will have long-term positive effects on sustainable agriculture aiming at simultaneously providing food security,increasing resource use efficiency,and maintaining environment integrity.

关键词： arbuscular mycorrhizal fungi-friendly management strategies carbon sequestration hyphosphere microbiome nutrient cycling soil aggregation soilfunctions

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

Resource Allocation for Cognitive Network slicing in PD-sCMA system Based on Two-way Deep Reinforcement Learning

引用

China Communications 2024年第6期21卷 53-68页

作者： zhang Zhenyu zhang Yong Yuan siyu Cheng Zhenjie school of Electronic Engineering Beijing University of Posts and TelecommunicationsBeijing 100876China Beijing Key Laboratory of work safety Intelligent Monitoring(Beijing University of Posts and Telecommunications) Beijing 100876China

In this paper,we propose the Two-way Deep Reinforcement Learning(DRL)-Based resource allocation algorithm,which solves the problem of resource allocation in the cognitive downlink network based on the underlay *** users(sUs)in the cognitive network are multiplexed by a new Power Domain sparse Code Multiple Access(PD-sCMA)scheme,and the physical resources of the cognitive base station are virtualized into two types of slices:enhanced mobile broadband(eMBB)slice and ultrareliable low latency communication(URLLC)*** design the Double Deep Q Network(DDQN)network output the optimal codebook assignment scheme and simultaneously use the Deep Deterministic Policy Gradient(DDPG)network output the optimal power allocation *** objective is to jointly optimize the spectral efficiency of the system and the Quality of service(Qos)of *** results show that the proposed algorithm outperforms the CNDDQN algorithm and modified JEERA algorithm in terms of spectral efficiency and Qos ***,compared with the Power Domain Non-orthogonal Multiple Access(PD-NOMA)slices and the sparse Code Multiple Access(sCMA)slices,the PD-sCMA slices can dramatically enhance spectral efficiency and increase the number of accessible users.

关键词： cognitive radio deep reinforcement learning network slicing power-domain non-orthogonal multiple access resource allocation

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

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：