检索结果-南通市图书馆

Task-Oriented Semantic Communication with Foundation Models

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

China Communications 2024年第7期21卷 65-77页

作者： Chen Mingkai Liu Minghao Zhang Zhe xu zhiping Wang Lei Key Laboratory of Broadband Wireless Communication and Sensor Network Technology Ministry of EducationNanjing University of Posts and TelecommunicationsNanjing 210003China School of Ocean Information Engineering Jimei UniversityXiamen 361021China Key Laboratory of Underwater Acoustic Communication and Marine Information Technology(Xiamen University) Ministry EducationXiamen 361005China

In the future development direction of the sixth generation(6G)mobile communication,several communication models are proposed to face the growing challenges of the *** rapid development of artificial intelligence(AI)foundation models provides significant support for efficient and intelligent communication *** this paper,we propose an innovative semantic communication paradigm called task-oriented semantic communication system with foundation ***,we segment the image by using task prompts based on the segment anything model(SAM)and contrastive language-image pretraining(CLIP).Meanwhile,we adopt Bezier curve to enhance the mask to improve the segmentation ***,we have differentiated semantic compression and transmission approaches for segmented ***,we fuse different semantic information based on the conditional diffusion model to generate high-quality images that satisfy the users'specific task ***,the experimental results show that the proposed system compresses the semantic information effectively and improves the robustness of semantic communication.

关键词： diffusion model foundation model joint source-channel coding task-oriented semantic communication

Carbon nanotube films with ultrahigh thermal-shock and thermalshock-fatigue resistance characterized by ultra-fast ascending shock testing

在线全文

学校读者我要写书评

暂无评论

Nano Research 2024年第8期17卷 6777-6784页

作者： Mingquan Zhu Shijun Wang Yunxiang Bai Feng Gao Zhenxing Zhu Congying Wang Peng Zhang Hao Jin Hui Zhang Luqi Liu zhiping xu Xinghong Zhang Fei Wei Zhong Zhang CAS Key Laboratory of Nanosystem and Hierarchical Fabrication CAS Center for Excellence in NanoscienceNational Center for Nanoscience and TechnologyChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology Department of Chemical EngineeringTsinghua UniversityBeijing 100084China Department of Engineering Mechanics Tsinghua UniversityBeijing 100084China National Key Laboratory of Science and Technology on Advanced Composites in Special Environments Center for Composite Materials and StructuresHarbin Institute of TechnologyHarbin 150001China CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Modern MechanicsUniversity of Science and Technology of ChinaHefei 230027China

The exploration of material failure behavior not only involves defining its limits and underlying mechanisms but also entails devising strategies for improvement and protection in extreme ***'ve pioneered an advanced multi-scale,high-speed ascending thermal shock testing platform capable of inducing unprecedented heat shocks at rates surpassing 105℃/*** meticulous examination of the thermal shock responses of carbon nanotube(CNT)films,we've achieved remarkable *** employing an innovative macro-scale synchronous tightening and relaxing approach,we've attained a critical temperature differential in CNT films that exceeds an exceptional 2500℃—surpassing any previously reported metric for highperformance,thermal-shock-resistant ***,these samples have demonstrated exceptional resilience,retaining virtually unchanged strength even after enduring 10,000 thermal shock cycles at temperatures exceeding 1000℃.Furthermore,our research has revealed a novel thermal shock/fatigue failure mechanism that fundamentally diverges from conventional theories centered on thermal stress.

关键词： carbon nanotubes failure behavior thermal shock characterization

The sedimentary structure characteristics and spatial distribution pattern of the Zhaoji Salt Mine derived from dense array ambient noise tomography

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

Journal of Earth Science 2024年

作者： Hongwei Wang Xiaofeng Tian Qiaoxia Liu Jia Cheng Ming Zhou zhiping xu Jiyan Lin Shuaipeng Zhu Geophysics Exploration Center China Earthquake Administration School of Earth Sciences and Resources， China University of Geosciences (Beijing)

Due to the lack of the three-dimensional structure of the Zhaoji salt basin， the salt mining enterprises have obvious clustering when choosing sites. Production capacity declines rapidly as mining deepens， the enterprises are entering a stage of stagnation in production. In this study， a dense seismic array of 125 short-period stations was deployed around the core mining area and its vicinity of the salt mine industry， we use the ambient noise tomography (ANT) method to image the three-dimensional shear wave velocity structure at the depth shallower than 3 km. The results indicate: (1) The overall shear wave velocity in the study area is relatively lower， ranging from 0.8 and 1.8 km/s， which could be related to the loose and thick deposition of the Zhaoji Sub-Depression. (2) The three-dimensional shear wave velocity structure reveals that the sedimentary thickness of the Zhaoji Sub-Depression is deeper in the southeast and shallower in the northwest， with the sedimentary center located around Heping Town and Dahuangzhuang Town. (3) The Zhaoji salt mine is a low-velocity anomalous zone in the shear wave velocity structure with an inverse 'C' character spreading along Nanchenji Town and Zhaoji Town， with a depth ranging from approximately 1.2 to 2.8 km， it may be caused by the development of rock fissures due to water extraction and injection. The surrounding rock exhibits relatively high velocity， which reflects the morphological characteristics of the Zhaoji salt basin. The three-dimensional shear wave velocity model obtained in this study provides scientific guidance for the industrial exploitation of the Zhaoji salt mine and reference for salt exploration of the Hongze Salt Basin. It also provides an important basis for the seismic risk assessment of the salt basins. Simultaneously， it holds significant implications for exploring the application of ambient noise tomography method in spatial detection of salt mine belt.

关键词：

膨胀性泥岩铁路隧道变形机理与仰拱底鼓控制技术研究

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

铁道标准设计 2024年第5期68卷 113-121页

作者：徐志平中铁第一勘察设计院集团有限公司西安710043

为揭示膨胀性泥岩铁路隧道仰拱底鼓变形机理并提出对应控制措施,以西(宁)至成(都)铁路膨胀性泥岩隧道为背景,采用室内试验、数值模拟、案例调研等方法开展研究。结果发现:膨胀性泥岩在浸水后物理力学参数明显降低,随着浸水时间增加,降... 详细信息

为揭示膨胀性泥岩铁路隧道仰拱底鼓变形机理并提出对应控制措施,以西(宁)至成(都)铁路膨胀性泥岩隧道为背景,采用室内试验、数值模拟、案例调研等方法开展研究。结果发现:膨胀性泥岩在浸水后物理力学参数明显降低,随着浸水时间增加,降低速率逐渐减小,其膨胀系数为4.8%;FLAC3D中的应变软化模型通过湿度应力场与温度应力场的转化能较好模拟膨胀性泥岩浸水后的参数衰减效应,当初始含水率分别为5%、15%、25%时,膨胀力试验结果分别为37.84,123.90,189.06kPa;随着水位上升,隧周孔隙水压力逐渐增大,当地下水位分别为Z=-5 m、Z=0 m、Z=5 m、Z=10 m、Z=15 m、Z=30 m时,隧周最大孔隙水压力分别为0,100,125,200,250,350 kPa,仰拱底部随软化系数的增加由沉降逐渐变为隆起,隧底围岩软化及上部挤压造成的剪切破坏是仰拱底鼓的最大诱因;随着仰拱矢跨比增加,二次衬砌弯矩减小,拱底和墙脚位置二次衬砌弯矩减小值较大,因此仰拱底部受力得到优化;适当提高仰拱矢跨比,采用全环钢架+钢筋混凝土衬砌、加强基底排水、采用基底换填或管桩加固等措施是膨胀性泥岩铁路隧道设计关键。

关键词：铁路隧道膨胀性泥岩仰拱底鼓变形机理变形控制技术参数优化

Robustness of structural superlubricity beyond rigid models

在线全文

学校读者我要写书评

暂无评论

Friction 2022年第9期10卷 1382-1392页

作者： Shizhe FENG zhiping xu Applied Mechanics Laboratory Department of Engineering Mechanics and Center for Nano and Micro MechanicsTsinghua UniversityBeijing 100084China

Structural superlubricity is a theoretical concept stating that the friction force is absent between two rigid,incommensurate crystalline ***,elasticity of the contact pairs could modify the lattice registry at interfaces by nucleating local slips,favoring *** validity of structural superlubricity is thus concerned for large-scale systems where the energy cost of elastic distortion to break the lattice registry is *** this work,we study the size dependence of superlubricity between single-crystal graphite *** dynamics simulations show that with nucleation and propagation of out-of-plane dislocations and strained solitons at Bernal interfaces,the friction force is reduced by one order of *** distortion is much weaker for non-Bernal or incommensurate ones,remaining notable only at the ends of *** self-organization at small twist angles perturbs the state of structural superlubricity through a reconstructed potential energy *** models are developed to illustrate and predict the interfacial elastoplastic behaviors at length scales beyond those in the *** results validate the rigid assumption for graphitic superlubricity systems at microscale,and reveal the intrinsic channels of mechanical energy *** understandings lay the ground for the design of structural superlubricity applications.

关键词： structural superlubricity lattice registry elastic deformation strained solitons crystal plasticity molecular dynamics simulations

N-苯基八元氧桥环新烟碱化合物的合成及其增效活性

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

农药学学报 2024年第1期26卷 44-51页

作者：谭都须志平邵旭升李忠华东理工大学药学院上海市化学生物学(芳香杂环)重点实验室上海200237

杀虫剂增效剂是提高杀虫剂杀虫效果和降低抗药性的关键成分。本文对具有特异性增效活性的八元氧桥环结构进一步衍生,设计合成了15个新型的N-苯基八元氧桥环新烟碱化合物,并测试了目标化合物与吡虫啉联用时对苜蓿蚜Aphis craccivora的致... 详细信息

杀虫剂增效剂是提高杀虫剂杀虫效果和降低抗药性的关键成分。本文对具有特异性增效活性的八元氧桥环结构进一步衍生,设计合成了15个新型的N-苯基八元氧桥环新烟碱化合物,并测试了目标化合物与吡虫啉联用时对苜蓿蚜Aphis craccivora的致死率。结果表明:在1 mg/L质量浓度下,大部分目标化合物能使吡虫啉对苜蓿蚜的毒力增加,表现出增效作用,其中苯环上无取代的化合物4a和4-CF3取代的化合物4m增效活性相当,其对吡虫啉毒力的增效倍数分别为3.44和3.58,可作为候选化合物进一步研究。

关键词：杀虫剂增效剂八元氧桥环新烟碱吡虫啉增效活性

Micro- and nano-mechanics in China： A brief review of recent progress and perspectives

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2018年第7期61卷 18-31页

作者： zhiping xu QuanShui Zheng Applied Mechanics Laboratory and Center for Nano and Micro Mechanics Department of Engineering Mechanics Tsinghua UniversityBeijing 100084 China

The past three decades have witnessed the explosion of nanoscience and technology, where notable research eftbrts have been made in synthesizing nanomaterials and controlling nanostructures of bulk materials. The uncovered mechanical behaviors of structures and materials with reduced sizes and dimensions pose open questions to the community of mechanicians, which expand the framework of continuum mechanics by advancing the theory, as well as modeling and experimental tools. Researchers in China have been actively involved into this exciting area, making remarkable contributions to the understanding of nanoscale mechanical processes, the development of multi-scale, multi-field modeling and experimental techniques to resolve the processing-microstructures-properties relationship of materials, and the interdisciplinary studies that broaden the subjects of mechanics. This article reviews selected progress made by this community, with the aim to clarify the key concepts, methods and applications of micro- and nano-mechanics, and to outline the perspectives in this fast-evolving field.

关键词： micro- and nano-mechanics multi-scale and multi-field methods nanotechnology nanomaterials nanostructurcs

A POSTERIORI ERROR ESTIMATES OF A NON-CONFORMING FINITE ELEMENT METHOD FOR PROBLEMS WITH ARTIFICIAL BOUNDARY CONDITIONS

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2009年第6期27卷 677-696页

作者： Xianmin xu zhiping Li LMAM & School of Mathematical Sciences Peking University Beijing 100871 China

An a posteriori error estimator is obtained for a nonconforming finite element approximation of a linear elliptic problem, which is derived from a corresponding unbounded domain problem by applying a nonlocal approximate artificial boundary condition. Our method can be easily extended to obtain a class of a posteriori error estimators for various conforming and nonconforming finite element approximations of problems with different artificial boundary conditions. The reliability and efficiency of our a posteriori error estimator are rigorously proved and are verified by numerical examples.

关键词： a posteriori estimate nonconforming finite element method artificial boundary conditions

分段式围手术期健康教育在妇科患者中的应用效果

在线全文

学校读者我要写书评

暂无评论

妇儿健康导刊 2024年第11期3卷 170-173页

作者：于红许志平江苏大学附属昆山市第一人民医院妇科江苏昆山215300 江苏大学附属昆山市第一人民医院全科医学科江苏昆山215300

目的观察分段式围手术期健康教育在妇科患者中的应用效果。方法选取2022年10月至2023年3月江苏大学附属昆山市第一人民医院妇科拟行择期手术的64例患者,采用随机数字表法将其分为试验组(n=32)与对照组(n=32)。对照组给予常规围手术期健... 详细信息

目的观察分段式围手术期健康教育在妇科患者中的应用效果。方法选取2022年10月至2023年3月江苏大学附属昆山市第一人民医院妇科拟行择期手术的64例患者,采用随机数字表法将其分为试验组(n=32)与对照组(n=32)。对照组给予常规围手术期健康教育,试验组给予分段式围手术期健康教育,比较两组焦虑评分、术后疼痛评分、满意度、住院时间、总依从率。结果试验组焦虑评分、术后疼痛评分低于对照组,满意度高于对照组,差异有统计学意义(P0.05);试验组总依从率高于对照组,差异有统计学意义(P<0.05)。结论分段式围手术期健康教育在妇科患者中的应用效果显著,可缓解焦虑,减轻术后疼痛,提高依从性和满意度,值得推广。

关键词：分段式围手术期健康教育焦虑依从性满意度

维普期刊数据库博看期刊