检索结果-南通市图书馆

High-order time-reversal symmetry breaking normal state

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2024年第3期67卷 136-148页

作者： Meng Zeng lun-hui hu Hong-Ye hu Yi-Zhuang You Congjun Wu Department of Physics University of CaliforniaSan DiegoCalifornia 92093USA Department of Physics Zhejiang UniversityHangzhou 310058China New Cornerstone Science Laboratory Department of PhysicsSchoolof ScienceWestlake UniversityHangzhou 30024China Institute for Theoretical Sciences Westlake UniversityHangzhou 310024China Key Laboratory for Quantum Materials of Zhejiang Province School of ScienceWestlake UniversityHangzhou 310024China Institute of Natural Sciences Westlake Institute for Advanced StudyHangzhou 310024China

Spontaneous time-reversal symmetry breaking plays an important role in studying strongly correlated unconventional *** two superconducting gap functions with different symmetries compete,the relative phase channel(θ_(-)≡θ_(1)-θ_(2))exhibits an Ising-type Z_(2) symmetry due to the second order Josephson coupling,where θ_(1,2) are the phases of two gap *** contrast,the U(1) symmetry in the channel of θ_(+)≡(θ_(1)+θ_(2))/2 is *** phase locking,i.e.,ordering of θ_(-),can take place in the phase fluctuation regime before the onset of superconductivity,i.e.,when θ_(+) is *** θ_(-) is pinned at ±π/2,then timereversal symmetry is broken in the normal state,otherwise,if θ_(-)=0,or,π,rotational symmetry is broken,leading to a nematic normal *** both cases,the order parameters possess a 4-fermion structure beyond the scope of mean-field theory,which can be viewed as a high order symmetry *** employ an effective two-component XY-model assisted by a renormalization group analysis to address this *** a natural by-product,we also find the other interesting intermediate phase corresponds to ordering of θ_+ but with θ_(-)*** is the quartetting,or,charge-4e,superconductivity,which occurs above the low temperature Z_(2)-breaking charge-2e superconducting *** results provide useful guidance for studying novel symmetry breaking phases in strongly correlated superconductors.

关键词： superconductivity strong correlation time-reversal breaking charge-4e

Learning Sequential and Structural Dependencies Between Nucleotides for RNA N6-Methyladenosine Site Identification

在线全文

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2024年第10期11卷 2123-2134页

作者： Guodong Li Bowei Zhao Xiaorui Su Dongxu Li Yue Yang Zhi Zeng lun hu Xinjiang Technical Institute of Physics and Chemistry Chinese Academy of Science the College of Computer Xi’an Jiaotong University IEEE

N6-methyladenosine(m6A) is an important RNA methylation modification involved in regulating diverse biological processes across multiple species. Hence, the identification of m6A modification sites provides valuable insight into the biological mechanisms of complex diseases at the post-transcriptional *** a variety of identification algorithms have been proposed recently, most of them capture the features of m6A modification sites by focusing on the sequential dependencies of nucleotides at different positions in RNA sequences, while ignoring the structural dependencies of nucleotides in their threedimensional structures. To overcome this issue, we propose a cross-species end-to-end deep learning model, namely CR-NSSD,which conduct a cross-domain representation learning process integrating nucleotide structural and sequential dependencies for RNA m6A site identification. Specifically, CR-NSSD first obtains the pre-coded representations of RNA sequences by incorporating the position information into single-nucleotide states with chaos game representation theory. It then constructs a crossdomain reconstruction encoder to learn the sequential and structural dependencies between nucleotides. By minimizing the reconstruction and binary cross-entropy losses, CR-NSSD is trained to complete the task of m6A site identification. Extensive experiments have demonstrated the promising performance of CR-NSSD by comparing it with several state-of-the-art m6A identification algorithms. Moreover, the results of cross-species prediction indicate that the integration of sequential and structural dependencies allows CR-NSSD to capture general features of m6A modification sites among different species, thus improving the accuracy of cross-species identification.

关键词： Cross-domain reconstruction cross-species prediction N6-methyladenosine (m6A) modification site RNA sequence sequential and structural dependencies

新文科背景下“双非”院校本科生科研投入程度及影响因素研究——以江西农业大学农林经济管理专业为例

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

科教文汇 2024年第9期 5-9页

作者：胡伦江西农业大学经济管理学院江西南昌330044

以江西农业大学农林经济管理专业本科生为例,了解“双非”院校农林专业本科生的科研投入程度及其影响因素,为优化本科生科研投入制度提供理论依据。调查得出以下结论:“双非”院校农林经济管理专业本科生的科研投入程度较低,且持续时间... 详细信息

以江西农业大学农林经济管理专业本科生为例,了解“双非”院校农林专业本科生的科研投入程度及其影响因素,为优化本科生科研投入制度提供理论依据。调查得出以下结论:“双非”院校农林经济管理专业本科生的科研投入程度较低,且持续时间较短;“不知道如何参与”和“耽误学习”是学生没有参与科研的关键因素;运用二元Probit模型、OLS回归模型分析后发现,年级、性别、党员身份、父亲职业对科研投入决策、科研投入程度和科研投入持续时间有显著正向影响,而年龄具有显著负向影响。

关键词： “双非”院校农林专业投入决策投入程度投入持续时间影响因素

在线全文

学校读者我要写书评

暂无评论

临近既有线地段架梁方式的选择

铁路工程技术与经济 2024年第4期39卷 33-36,42页

作者：胡伦中国铁路设计集团有限公司天津300308

高速铁路架设箱梁运梁方式一般有桥位跨墩提梁上桥或路基段利用运梁便道运梁上桥两种方式,对梁场位置的选择及项目的地形条件等提出了较高的要求。本文以某高铁联络线为例,研究桥位修建钢栈桥运梁上桥的方式,为箱梁的运输提供一个新的思... 详细信息

高速铁路架设箱梁运梁方式一般有桥位跨墩提梁上桥或路基段利用运梁便道运梁上桥两种方式,对梁场位置的选择及项目的地形条件等提出了较高的要求。本文以某高铁联络线为例,研究桥位修建钢栈桥运梁上桥的方式,为箱梁的运输提供一个新的思路,从而解决困难地段的架梁问题。文中通过分析箱梁制存梁场选址及箱梁上线方式重难点,提出两种架梁比选方案,从方案可行性、费用、工期以及存在的问题等方面进行对比分析,最终给出推荐方案。推荐方案在本项目已成功实施。研究成果可对今后类似工程的设计施工提供良好的借鉴和参考价值。

关键词：邻近既有线架梁运梁马道钢栈桥

热键合、凹端面及晶体棒直径对Er∶YSGG中红外激光性能的影响

在线全文

学校读者我要写书评

暂无评论

光谱学与光谱分析 2024年第2期44卷 571-579页

作者：程毛杰董昆鹏胡伦珍张会丽罗建乔权聪韩志远孙敦陆中国科学技术大学安徽合肥230026 中国科学院合肥物质科学研究院安徽光学精密机械研究所安徽合肥230031 安徽大学安徽合肥230601 安徽省先进激光技术实验室安徽合肥230037

对热键合、凹端面及不同直径Er∶YSGG晶体棒的中红外激光性能进行了系统对比研究。晶体经高温退火、定向切割、端面精密抛光后,测量得到其平面度和表面粗糙度分别小于0.1λ@633 nm和0.5 nm。通过精密加工实现了YSGG与Er∶YSGG室温光胶,... 详细信息

对热键合、凹端面及不同直径Er∶YSGG晶体棒的中红外激光性能进行了系统对比研究。晶体经高温退火、定向切割、端面精密抛光后,测量得到其平面度和表面粗糙度分别小于0.1λ@633 nm和0.5 nm。通过精密加工实现了YSGG与Er∶YSGG室温光胶,然后进行了高温热键合,透过谱表明键合界面基本无损耗,达到了一体化。热焦距结果表明,热键合、凹端面能够有效改善和补偿高功率泵浦条件下晶体的热透镜效应,有利于提高晶体的激光性能。对比未键合、热键合及凹面热键合Er∶YSGG晶体在968 nm LD侧面泵浦条件下的激光性能发现,低频150 Hz以下,键合与凹面并未表现出优势,三种棒的最大输出功率和斜效率分别均在24 W和28%附近;但随重频增加,热效应逐渐加重,键合晶体良好散热能力和凹面热补偿效应使激光性能得到提高。在重频300 Hz下,未键合、热键合及凹面热键合三种棒的最大输出功率分别为15.54,17.85和18.33 W、斜效率分别为16.6%,18.3%和18.4%;重频600 Hz条件下,三种棒的最大输出功率分别为9.4,13.32和13.18 W、斜效率分别为6.7%,8.6%和9%。此外,对比研究了不同直径Er∶YSGG晶体的激光性能,在低于100 Hz的低频下,三种晶体的激光性能接近。但相比于3和4 mm键合凹面棒,直径2 mm棒有大的比表面积,拥有更好的热管理能力,使其在高重频条件下具有更好的激光性能。如在150 Hz条件下,2 mm凹面键合Er∶YSGG晶体棒获得了功率23.82 W、斜效率27.7%的中红外激光输出,大大高于直径3和4 mm棒的18 W和23%。在600 Hz,直径2 mm键合凹面棒中实现了功率13.18 W,斜效率9%的激光输出,相比于直径3和4 mm键合凹面棒的9 W,7%具有较大的改善。测量得到2 mm凹面键合Er∶YSGG晶体棒在150 Hz,200μs条件下的光束质量因子M_(x)^(2)/M_(y)^(2)=6.28/6.30,表明该激光具有良好的光束质量。综上,选择合适晶体棒直径,并将键合与凹面相结合是实现高性能2.79μm激光的有效方法。

关键词：热键合 Er∶YSGG激光晶体凹端面 LD侧面泵浦 2.79μm中红外激光斜效率光束质量因子

A Distributed Framework for Large-scale Protein-protein Interaction Data Analysis and Prediction Using MapReduce

在线全文

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2022年第1期9卷 160-172页

作者： lun hu Shicheng Yang Xin Luo huaqiang Yuan Khaled Sedraoui MengChu Zhou School of Computer Science and Technology Dongguan University of TechnologyDongguan 523808China School of Computer Science and Technology Wuhan University of TechnologyWuhan 430070China Chongqing Engineering Research Center of Big Data Application for Smart Cities and Chongqing Key Laboratory of Big Data and Intelligent ComputingChongqing Institute of Green and Intelligent TechnologyChinese Academy of SciencesChongqing 400714China Xinjiang Technical Institute of Physics and Chemistry Chinese Academy of SciencesUrumqi 830000China Center of Research Excellence in Renewable Energy and Power Systems and the Department of Electrical and Computer EngineeringFaculty of EngineeringKing Abdulaziz UniversityJeddah 21589Saudi Arabia Department of Electrical and Computer Engineering New Jersey Institute of TechnologyNewarkNJ 07102 USA

Protein-protein interactions are of great significance for human to understand the functional mechanisms of *** the rapid development of high-throughput genomic technologies,massive protein-protein interaction(PPI)data have been generated,making it very difficult to analyze them *** address this problem,this paper presents a distributed framework by reimplementing one of state-of-the-art algorithms,i.e.,CoFex,using *** do so,an in-depth analysis of its limitations is conducted from the perspectives of efficiency and memory consumption when applying it for large-scale PPI data analysis and *** solutions are then devised to overcome these *** particular,we adopt a novel tree-based data structure to reduce the heavy memory consumption caused by the huge sequence information of *** that,its procedure is modified by following the MapReduce framework to take the prediction task distributively.A series of extensive experiments have been conducted to evaluate the performance of our framework in terms of both efficiency and *** results well demonstrate that the proposed framework can considerably improve its computational efficiency by more than two orders of magnitude while retaining the same high accuracy.

关键词： Distributed computing large-scale prediction machine learning MapReduce protein-protein interaction(PPI)

A new model simulating the development of gas condensate reservoirs

在线全文

学校读者我要写书评

暂无评论

Energy Geoscience 2024年第1期5卷 239-248页

作者： Yang Yang Zengmin lun Rui Wang Maolei Cui Wei hu Petroleum Exploration and Production Research Institute SINOPECBeijing100083China

A new simulation model for the development of gas condensate reservoirs is introduced based on the influence that phase change,non-Darcy flow,and capillary pressure have on the production of gas *** model predicts well performance,including bottom-hole pressure,oil/gas production rate,oil/gas recovery,gaseoil ratio,and the change in produced fluid *** also calculates dynamic characters,such as the change of pressure field and oil/gas saturation field during the development of gas condensate *** model is applicable to different boundary conditions(both constant-pressure and sealed boundary)and different production modes(both constant-pressure and constant-volume production modes).Model validation attempted using numerical simulation results for sealed boundary conditions with constant-pressure production mode has shown a relatively good match,proving its *** constant-pressure boundary conditions with constant-volume production mode,four stages are defined according to the dynamic behavior of production performance in the development of gas condensate reservoirs.

关键词： Gas condensate reservoir Phase behavior Numerical simulation Pseudo-pressure method

Photoinduced transposed Paternò-Büchi reaction for effective synthesis of high-performance jet fuel

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

Chinese Journal of Chemical Engineering 2024年第3期67卷 39-48页

作者： Jinxiu hu Xianlong Liu Yi Liu Kang Xue Chengxiang Shi Xiangwen Zhang Li Wang Ji-Jun Zou lun Pan Key Laboratory for Green Chemical Technology of the Ministry of Education School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China Haihe Laboratory of Sustainable Chemical Transformations Tianjin 300192China Zhejiang Institute of Tianjin University Ningbo 315201China Collaborative Innovative Center of Chemical Science and Engineering(Tianjin) Tianjin 300072China

High-energy-density fuels are important for volume-limited aerospace vehicles,but the increase in fuel energy density always leads to poor cryogenic ***,we investigated the transposed Paternò-Büchi reaction of biomass cyclic ketone and cyclic alkene to synthesize a new kind of alkyl-substituted polycyclic hydrocarbon fuel with high energy density and good cryogenic *** triplet-energy-quenching results and phosphorescent emission spectra reveal the sensitization mechanism of the reaction,including photosensitizer excitation,triplettriplet energy transfer,cyclization,and relaxation,and the possible reaction path was revealed by the density functional theory(DFT)*** reaction conditions of photosensitizer type and addition,molar ratio of substrates,reaction temperature,and incident light intensity were optimized,with the target product yield achieving 65.5%.Moreover,the reaction dynamics of the reaction rate versus the light intensity are *** the hydrogenation-deoxygenation reaction,three fuels with a high density of 0.864-0.938 g·ml^(-1) and a low freezing point of<-55℃ are *** work provides a benign and effective approach to synthesize high-performance fuels.

关键词： High-energy-density fuel Transposed Patern-oeBüchi reaction Kinetics Bioenergy Photochemistry

开绕组BLDCM直接转矩控制电压矢量特性研究

在线全文

学校读者我要写书评

暂无评论

微特电机 2024年第4期52卷 8-15页

作者：华文韬杨建飞邱鑫陈秋仲刘业胡伦周锴刘畅陈洪生南京师范大学电气与自动化工程学院江苏省三维打印装备与制造重点实验室南京210023

基于直接转矩控制(DTC)的开绕组无刷直流电机(BLDCM)具有运行效率高、电压矢量多样、控制结构简单等优点,适用于工业领域。根据共直流母线开绕组BLDCM控制拓扑搭建了相应的数学模型,对该拓扑下电压矢量的特性进行理论分析及分类,并将电... 详细信息

基于直接转矩控制(DTC)的开绕组无刷直流电机(BLDCM)具有运行效率高、电压矢量多样、控制结构简单等优点,适用于工业领域。根据共直流母线开绕组BLDCM控制拓扑搭建了相应的数学模型,对该拓扑下电压矢量的特性进行理论分析及分类,并将电压幅值不为零的电压矢量分为大、中、小三类。分析结果表明:在相同的运行条件下,大矢量作用下转矩变化率最大,小矢量作用下转矩变化率最小,中矢量居于两者之间。仿真结果验证了理论分析的正确性和控制方法的可行性。

关键词：无刷直流电机开绕组直接转矩控制两相导通电压矢量