检索结果-南通市图书馆

ARPES investigation of the electronic structure and its evolution in magnetic topological insulator MnBi2+2nTe4+3n family

在线全文

学校读者我要写书评

暂无评论

National Science Review 2024年第2期11卷 81-93页

作者： Runzhe Xu Lixuan Xu Zhongkai Liu Lexian Yang yulin Chen State Key Laboratory of Low Dimensional Quantum Physics Department of PhysicsTsinghua University School of Physical Science and Technology Shanghai Tech University and CAS-Shanghai Science Research Center Shanghai Tech Laboratory for Topological Physics Frontier Science Center for Quantum Information Collaborative Innovation Center of Quantum Matter Department of Physics Clarendon LaboratoryUniversity of Oxford

In the past 5 years,there has been significant research interest in the intrinsic magnetic topological insulator family compounds MnBi2+2nTe4+3n（where n=0,1,2…）.In particular,exfoliated thin films of MnBi2Te4have led to numerous experimental breakthroughs,such as the quantum anomalous Hall effect,axion insulator phase and high-Chern number quantum Hall effect without Landau ***,despite extensive efforts,the energy gap of the topological surface states due to exchange magnetic coupling,which is a key feature of the characteristic band structure of the system,remains experimentally *** electronic structure measured by using angle-resolved photoemission （ARPES） shows significant deviation from ab initio prediction and scanning tunneling spectroscopy measurements,making it challenging to understand the transport results based on the electronic *** paper reviews the measurements of the band structure of MnBi2+2nTe4+3nmagnetic topological insulators using ARPES,focusing on the evolution of their electronic structures with temperature,surface and bulk doping and film *** aim of the review is to construct a unified picture of the electronic structure of MnBi2+2nTe4+3ncompounds and explore possible control of their topological properties.

关键词： magnetic topological insulator MnBi2Te4 electronic structure angle-resolved photoemission spectroscopy

Effects of urban street trees on human thermal comfort and physiological indices: a case study in Changchun city, China

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Forestry Research 2022年第3期33卷 911-922页

作者： Zhibin Ren Hongbo Zhao Yao Fu Lu Xiao yulin Dong Key Laboratory of Wetland Ecology and Environment Northeast Institute of Geography and AgroecologyChinese Academy of SciencesChangchun130102P.R.China Key Research Institute of Yellow River Civilization and Sustainable Development&Collaborative Innovation Center On Yellow River Civilization Jointly Built By Henan Province and Ministry of Education Henan UniversityKaifeng475001P.R.China School of Geography and Engineering of Land Resources Yuxi Normal UniversityYuxi653100P.R.China University of Chinese Academy of Sciences Beijing100049P.R.China

Planting trees along urban streets is one of the most important strategies to improve the urban thermal ***,the net impacts of urban street trees on human thermal comfort and physiological parameters are still less *** three similar east-west orientated streets with different degrees of tree cover-low(13%),medium(35%),and high(75%),urban microclimatic parameters and human physiological indices for six male students were simultaneously measured on three cloudless days in summer *** results show that the differences in tree cover were predominant in influencing urban thermal environment and *** street with the highest tree cover had significantly lower physiological equivalent temperature(PET) and more comfortable than the other two *** frequency of strong heat stress(PET> 35℃) was 64%,11 %,and 0%,respectively,for streets with low,medium,and high tree *** the six male university students,human physiological indices varied greatly across the three streets with different tree *** blood pressure,diastolic blood pressure,and pulse rate increased with decreasing tree *** results also suggest that urban thermal environment and comfort had considerable impact on human physiological *** study provides reasons for urban planners to plant trees along streets to improve the thermal environment and promote urban sustainability.

关键词： Urban forest Green space Environmental ecosystem services Urban thermal comfort Blood pressure Pulse rate

Precise time frequency synchronization technology for bistatic radar

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2008年第5期19卷 929-933页

作者： Huang yulin Yang Jianyu Wu Junjie Xiong jintao School of Electronic Engineering Univ. of Electronic Science and Technology of China Chengdu 610054 P. R. China

A complete method of synchronization technology of bistatic radar using global position system （GPS） is presented. The pulse per second signal （1PPS） is elaborately modified to increase the time synchronization precision and keep loop locking. A very high time synchronization precision is achieved. Using the modified 1PPS to discipline the local OCXO, the reference frequency signal achieves both high long term stability （LTS） and short term stability （STS） properties. An algorithm, named phase abrupt change CFAR is presented to restrain the 1PPS phase abrupt change and keep loop locking. The experimental results indicate that this time and frequency synchronization method is effective and the time synchronization precision of the synchronization system can be improved from ±100 ns to ±25 ns. In addition, the phase noise is improved to 20 dB.

关键词： bistatic radar GPS time synchronization frequency phase synchronization.

茶色素对高血脂、异常血液流变及冠心病的治疗作用

在线全文

学校读者我要写书评

暂无评论

中国血液流变学杂志 1997年第4期7卷 27-29页

作者：徐玉林李振中金吉明王洪文陈德生许宗磊杨国军山东聊城市人民医院 252000

选取高脂血症、血流变异常患者１００例，伴冠心病患者６４例。口服茶色素１２５ｍｇ／次，每日３次，２个月为一疗程。服药前后查血脂、血流变、心电图，采用自身对照分析疗效。结果显示：①明显降低ＴＣ、ＴＧ和升高升高ＨＤＬ—... 详细信息

选取高脂血症、血流变异常患者１００例，伴冠心病患者６４例。口服茶色素１２５ｍｇ／次，每日３次，２个月为一疗程。服药前后查血脂、血流变、心电图，采用自身对照分析疗效。结果显示：①明显降低ＴＣ、ＴＧ和升高升高ＨＤＬ—Ｃ（Ｐ＜０．０５），显著降低ＬＤＬ—Ｃ（Ｐ＜０．０１）；②显著降低全血粘度、血浆粘度、纤维蛋白原（Ｐ＜０．０１）；明显降低全血还原粘度（Ｐ＜０．０５）；③伴冠心病心绞痛者显效２６．６％（１７／６４）、有效５４．６％（３５／６４）、总有效８１．２％（５２／６４）．说明茶色素具有降脂、抗凝、促纤溶、治疗冠心病等多种药理作用。１００例病人均无明显毒副作用。

关键词：茶色素高脂血症血液流变学冠心病治疗

An Al–Al interpenetrating-phase composite by 3D printing and hot extrusion

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2023年第4期30卷 678-688页

作者： yulin Lin Di Wang Chao Yang Weiwen Zhang Zhi Wang School of Mechanical and Automotive Engineering South China University of TechnologyGuangzhou 510640China Guangdong Key Laboratory for Processing and Forming of Advanced Metallic Materials South China University of TechnologyGuangzhou 510640China

We report a process route to fabricate an Al–Al interpenetrating-phase composite by combining the Al–Mg–Mn–Sc–Zr lattice structure and Al_(84)Ni_(7)Gd_(6)Co_(3)nanostructured structure. The lattice structure was produced by the selective laser melting and subsequently filled with the Al_(84)Ni_(7)Gd_(6)Co_(3)amorphous powder, and finally the mixture was used for hot extrusion to produce bulk samples. The results show that the composites achieve a high densification and good interface bonding due to the element diffusion and plastic deformation during hot *** bulk samples show a heterogeneous structure with a combination of honeycomb lattice structure with an average grain size of less than1 μm and nanostructured area with a high volume fraction of nanometric intermetallics and nanograin α-Al. The heterogeneous structure leads to a bimodal mechanical zone with hard area and soft area giving rise to high strength and acceptable plasticity, where the compressive yield strength and the compressive plasticity can reach ~745 MPa and ~30%, respectively. The high strength can be explained by the rule of mixture,the grain boundary strengthening, and the back stress, while the acceptable plasticity is mainly owing to the confinement effect of the nanostructured area retarding the brittle fracture behavior.

关键词： Al-based composites heterogeneous structure additive manufacturing mechanical properties

Software approaches for resilience of high performance computing systems:a survey

在线全文

学校读者我要写书评

暂无评论

Frontiers of Computer Science 2023年第4期17卷 43-56页

作者： Jie JIA Yi LIU Guozhen ZHANG yulin GAO Depei QIAN School of Computer Science and Engineering Beihang UniversityBeijing 100191China Sino-German Joint Software Institute Beihang UniversityBeijing 100191China

With the scaling up of high-performance computing systems in recent years,their reliability has been descending ***,system resilience has been regarded as one of the critical challenges for large-scale HPC *** techniques and systems have been proposed to ensure the correct execution and completion of parallel *** paper provides a comprehensive survey of existing software resilience ***,a classification of software resilience approaches is presented;then we introduce major approaches and techniques,including checkpointing,replication,soft error resilience,algorithmbased fault tolerance,fault detection and *** addition,challenges exposed by system-scale and heterogeneous architecture are also discussed.

关键词： resilience high-performance computing fault tolerance challenge

同方期刊数据库

Dynamic compression characteristics of layered rock mass of significant strength changes in adjacent layers

在线全文

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2020年第2期12卷 353-365页

作者： Sen Wen Chunshun Zhang yulin Chang Ping Hu Institute of Geotechnical and Rail Transport Engineering Henan UniversityKaifeng475004China Department of Civil Engineering Monash UniversityClaytonVIC3800Australia School of Civil Engineering University of South ChinaHengyang421001China

Layered rock mass of significant strength changes for adjacent layers is frequently observed in underground excavation,and dynamic loading is a prevalent scenario generated during *** order to improve the driving efficiency and reduce engineering accidents,dynamic compression characteristics of this kind of rock mass should be *** dynamic properties of a layered composite rock mass are investigated through a series of rock tests and numerical *** rock mass is artificially made of various proportions of sand,cement and water to control the distinct strength variations at various composite layers separated by parallel bedding *** rock specimens are prefabricated in a specially designed mould and then cut into 50 mm in diameter and 50 mm in height for split Hopkinson pressure bar(SHPB)dynamic compression *** test results reveal that increasing strain rate causes the increases of peak strength,σ_p,and the corresponding failure strain,ε_p,while the dynamic elastic modulus,E_d,remains almost ***,under the same strain rates,Ed of the composite rock specimen is found to decline first and then increase as the dip angle of bedding plane *** obtained rock failure patterns due to various dip angles lead to failure modes that could be classified into four categories from our dynamic ***,a series of counterpart numerical simulations has been undertaken,showing that dynamic responses are in good agreement with those obtained from the SHPB *** numerical analysis enables us to Iook into the dynamic characteristics of the composite rock mass subjected to a broader range of strain rates and dip angles than these being tested.

关键词： Rock dynamics Split hopkinson pressure bar(SHPB) Layered composite rock specimen Dip angle of bedding plane Strain rate Numerical simulation

High-Energy Batteries:Beyond Lithium-Ion and Their Long Road to Commercialisation

在线全文

学校读者我要写书评

暂无评论

Nano-Micro Letters 2022年第6期14卷 116-164页

作者： yulin Gao Zhenghui Pan Jianguo Sun Zhaolin Liu John Wang Department of Materials Science and Engineering National University of SingaporeSingapore 117574Singapore ST Engineering Advanced Material Engineering Pte.Ltd. Singapore 619523Singapore Institute of Materials Research and Engineering Agency for ScienceTechnology and Research(A*STAR)Singapore 138634Singapore School of Materials Science and Engineering Tongji UniversityShanghai 201804China

Rechargeable batteries of high energy density and overall performance are becoming a critically important technology in the rapidly changing society of the twenty-first *** lithium-ion batteries have so far been the dominant choice,numerous emerging applications call for higher capacity,better safety and lower costs while maintaining sufficient *** design space for potentially better alternatives is extremely large,with numerous new chemistries and architectures being simultaneously *** include other insertion ions(*** and numerous multivalent ions),conversion electrode materials(***,metallic anodes,halides and chalcogens)and aqueous and solid ***,each of these potential“beyond lithium-ion”alternatives faces numerous challenges that often lead to very poor cyclability,especially at the commercial cell level,while lithium-ion batteries continue to improve in performance and decrease in *** review examines fundamental principles to rationalise these numerous developments,and in each case,a brief overview is given on the advantages,advances,remaining challenges preventing cell-level implementation and the state-of-the-art of the solutions to these ***,research and development results obtained in academia are compared to emerging commercial examples,as a commentary on the current and near-future viability of these“beyond lithium-ion”alternatives.

关键词： High energy density Beyond lithium-ion batteries Multivalent-ion batteries Conversion electrode materials Electrolyte

Compressed Sensing of Wireless Sensor Networks Data with Missed Measurements

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Electronics 2015年第2期24卷 388-392页

作者： WANG Kai LIU yulin WAN Qun jinG Xiaojun Chongqing Communication Institute China Electronic System Engineering Company University of Electronic Science and Technology of China Beijing University of Posts and Telecommunications

In Wireless sensor networks(WSNs),missed measurements may be caused by the sensor malfunction and interruption of communication between sensor nodes. The feasibility of exact recovery of WSNs data with missed measurements is analyzed in the framework of compressed sensing. A new incomplete measurement model was developed and the data reconstruction algorithm was proposed. The required number of the missing measurements and the sparsity condition of network data are found for exact compressed sensing of WSNs *** derivation shows that a WSNs data of length N with no more than M/(log(N/M) + 1) nonzero coefficients can be exactly recovered with M Gaussian measurements,provided that fraction of the missed measurements is less than a quarter of the Restricted isometry property(RIP)constant squared. Simulation results validate the theoretical results.

关键词： Wireless sensor networks Compressed sensing Missed measurements Data reconstruction