检索结果-南通市图书馆

Scalable preparation and direct visualization of cyclic polymers via self-folding cyclization technique

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2022年第12期65卷 2558-2566页

作者： hualong zhang Hao Zha Chao Liu Chunyan Hong CAS Key Laboratory of Soft Matter Chemistry Department of Polymer Science and EngineeringUniversity of Science and Technology of ChinaHefei230026China

Cyclic polymers exhibit distinct properties compared with their linear counterparts due to the lack of chain ends.However,the scalable synthesis of cyclic polymers remains a major challenge,especially for ring-closure method.Herein,we report a novel strategy for large-scale preparation of cyclic polymers,which relies on the prior self-folding of anthracene-telechelic amphiphilic random copolymers(poly((oligo(ethylene glycol)acrylate)-co-(dodecyl acrylate)),P(OEGA-co-DDA))into single-chain polymeric nanoparticles(SCPNs)in water.Subsequent ultraviolet(UV)-induced cyclization occurs in the hydrophobic nano-domain.The formation of SCPNs leads to a shortened distance between the end groups of the linear precursors and spatially separated cyclization loci,and significantly enhances the efficiency of UV-induced cyclization.This self-folding technique permits access to the synthesis of cyclic polymers not only with high molecular weights(M_(n)>10^(5) g/mol),but also in a decent scale(40 g/L),breaking through the limitations of ring-closure method.Furthermore,the dense pendants of the copolymers can magnify the macromolecules by increasing the mass density along the backbones,thus making the polymers more readily detectable by the microscopy.The transmission electron microscopy(TEM)and atomic force microscopy(AFM)images allow us to observe the topological structures directly and provide crucial evidence to confirm the cyclization.

关键词： cyclic polymer scalable preparation direct visualization self-folding cyclization technique

Two antibodies show broad,synergistic neutralization against SARS-CoV-2 variants by inducing conformational change within the RBD

在线全文

学校读者我要写书评

暂无评论

Protein & Cell 2024年第2期15卷 121-134页

作者： Hui Sun Tingting Deng Yali zhang Yanling Lin Yanan Jiang Yichao Jiang Yang Huang Shuo Song Lingyan Cui Tingting Li hualong Xiong Miaolin Lan Liqin Liu Yu Li Qianjiao Fang Kunyu Yu Wenling Jiang Lizhi Zhou Yuqiong Que Tianying zhang Quan Yuan Tong Cheng Zheng zhang Hai Yu Jun zhang Wenxin Luo Shaowei Li Qingbing Zheng Ying Gu Ningshao Xia State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics School of Public HealthSchool of Life SciencesXiamen UniversityXiamen 361102China National Institute of Diagnostics and Vaccine Development in Infectious Diseases School of Public HealthSchool of Life SciencesXiamen UniversityXiamen 361102China State Key Laboratory of Vaccines for Infectious Diseases School of Public HealthSchool of Life SciencesXiamen UniversityXiamen 361102China Xiang An Biomedicine Laboratory Xiamen 361102China Institute for Hepatology National Clinical Research Center for Infectious DiseaseShenzhen Third People's HospitalSchool of MedicineSouthem University of Science and TechnologyShenzhen 518112China The Second Affliated Hospital School of MedicineSouthern University of Science and TechnologyShenzhen 518112China Research Unit of Frontier Technology of Structural Vaccinology Chinese Academy of Medical SciencesXiamen 361102China

Continual evolution of the severe acute respiratory syndrome coronavirus(SARS-CoV-2)virus has allowed for its gradual evasion of neutralizing antibodies(nAbs)produced in response to natural infection or vaccination.The rapid nature of these changes has incited a need for the development of superior broad nAbs(bnAbs)and/or the rational design of an antibody cocktail that can protect against the mutated virus strain.Here,we report two angiotensin-converting enzyme 2 competing nAbs—8H12 and 3E2—with synergistic neutralization but evaded by some Omicron subvariants.Cryo-electron microscopy reveals the two nAbs synergistic neutralizing virus through a rigorous pairing permitted by rearrangement of the 472-489 loop in the receptor-binding domain to avoid steric clashing.Bispecific antibodies based on these two nAbs tremendously extend the neutralizing breadth and restore neutralization against recent variants including currently dominant XBB.1.5.Together,these findings expand our understanding of the potential strategies for the neutralization of SARS-CoV-2 variants toward the design of broad-acting antibody therapeutics and vaccines.

关键词： SARS-CoV-2 broad neutralizing antibody rearrangement synergistic neutralization

Structural and electronic effects boosting Ni-doped Mo_(2)C catalyst toward high-efficiency C-O/C-C bonds cleavage

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 Energy Chemistry 2022年第12期75卷 109-116,I0004页

作者： Xiangze Du Jinjia Liu Dan Li Hui Xin Xiaomei Lei Rui zhang Linyuan Zhou Huiru Yang Yan Zeng hualong zhang Wentao Zheng Xiaodong Wen Changwei Hu Key Laboratory of Green Chemistry and Technology College of ChemistrySichuan UniversityChengdu 610064SichuanChina State Key Laboratory of Coal Conversion Institute of Coal ChemistryChinese Academy of SciencesTaiyuan 030001ShanxiChina National Energy Center for Coal to Liquids Synfuels China Co.LtdBeijing 101400China Department State Key Laboratory of Catalysis iChEMDalian Institute of Chemical PhysicsChinese Academy of ScienceDalian 116023LiaoningChina Department of Chemistry University of HelsinkiA.I.Virtasen Aukio 1P.O.Box 5500014Finland

The selective cleavage of C-O and C-C is facing a challenge in the field of catalysis.In the present work,we studied the influence of doped Ni on the structure and electronic properties,as well as the selective C-O/C-C bond cleavages in the hydrodeoxygenation of palmitic acid over Ni-Mo_(2)C catalyst.The catalytic activity on Ni doped Mo_(2)C with TOF of 6.9×10^(3)h^(-1)is much superior to intrinsic Mo_(2)C catalyst,which is also higher than most noble metal catalysts.Structurally,the doped Ni raises the active particle dispersion and the coordination numbers of Mo species(Mo-C and Mo-O),improves the graphitization degree to promote the electron transfer,and increases the amount of Lewis and Br?nsted acid,which are responsible for the excellent hydrodeoxygenation performance.The Ni promotes simultaneously C-O and C-C bonds cleavage to produce pentadecane and hexadecane owing to the increase of electron-rich Mo sites after Ni doping.These findings contribute to the understanding of the nature of Ni-doped Mo_(2)C on the roles as catalytic active sites for C-O and C-C bonds cleavage.

关键词： Ni-doped Mo_(2)C Palmitic acid Hydrodeoxygenation C-O/C-C bond cleavages Biofuel

Wintertime peroxyacetyl nitrate(PAN) in the megacity Beijing: Role of photochemical and meteorological processes

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2014年第1期26卷 83-96页

作者： hualong zhang Xiaobin Xu Weili Lin Ying Wang Key Laboratory for Atmospheric Chemistry China Meteorological Administration Institute of Atmospheric Composition Chinese Academy of Meteorological Sciences Meteorological Observation Centre China Meteorological Administration

Previous measurements of peroxyacetyl nitrate （PAN） in Asian megacities were scarce and mainly conducted for relative short periods in summer. Here, we present and analyze the measurements of PAN, O3, NOx, etc., made at an urban site （CMA） in Beijing from 25 January to 22 March 2010. The hourly concentration of PAN averaged 0.70 × 10^-9 mol/mol （0.23 × 10^9-3.51 × 10^9 mol/mol） and was well correlated with that of NOa but not O3, indicating that the variations of the winter concentrations of PAN and O3 in urban Beijing are decoupled with each other. Wind conditions and transport of air masses exert very significant impacts on O3, PAN, and other species. Air masses arriving at the site originated either from the boundary layer over the highly polluted N-S-W sector or from the free troposphere over the W-N sector. The descending free-tropospheric air was rich in O3, with an average PAN/O3 ratio smaller than 0.O31, while the boundary layer air over the polluted sector contained higher levels of PAN and primary pollutants, with an average PAN/O3 ratio of 0.11. These facts related with transport conditions can well explain the observed PAN-O3 decoupling. Photochemical production is important to PAN in the winter over Beijing. The concentration of the peroxyacetyl （PA） radicai was estimated to be in the range of 0.0014 × 10^-12～0.0042 × 10^-12 mol/mol. The contributions of the formation reaction and thermal decomposition to PAN＇s variation were calculated and found to be significant even in the colder period in air over Beijing, with the production exceeding the decomposition.

关键词： peroxyacetyl nitrate photochemical production wintertime urban Beijing

自分级挤压式核桃破壳机关键部件作业参数优化与试验

在线全文

学校读者我要写书评

暂无评论

中国农机化学报 2024年第4期45卷 85-92页

作者：刘华龙曾勇张宏塔里木大学机械电气化工程学院新疆阿拉尔843300 新疆维吾尔自治区教育厅普通高等学校现代农业工程重点实验室新疆阿拉尔843300

通过分析不同作业参数对自分级挤压式核桃破壳机破壳性能的影响规律,优化关键部件的作业参数,提高破壳性能。以核桃在辊板间的运动学分析为基础,确定影响核桃破壳取仁的关键因素为破壳角度和轧辊转速,并以破壳率、整仁率和能耗为试验指... 详细信息

通过分析不同作业参数对自分级挤压式核桃破壳机破壳性能的影响规律,优化关键部件的作业参数,提高破壳性能。以核桃在辊板间的运动学分析为基础,确定影响核桃破壳取仁的关键因素为破壳角度和轧辊转速,并以破壳率、整仁率和能耗为试验指标,开展两因素五水平二次正交旋转中心组合试验。利用Design-Expert软件进行数据分析,建立各因素和试验指标之间的回归模型并进行方差分析,得到影响破壳率、整仁率和能耗的主次因素。利用响应面法分析两个因素的交互作用,根据优化目标的重要程度对回归模型进行多目标优化。试验结果表明:最优工作参数组合为破壳角度0.47°,轧辊转速108 r/min,在此条件下,得出破壳率为97.24%,整仁率为92.03%,能耗为1.88 kJ/kg,验证试验结果与模型预测值相对误差小于5%。品种适应性试验结果表明:最优工作参数对3个品种核桃(温185、新温179、扎343)的适应性较佳,表现为破壳率均大于96%,整仁率均大于90%,能耗均小于2 kJ/kg。为相关破壳取仁设备改进与优化以及不同品种核桃破壳加工参数的选取提供理论参考。

关键词：核桃破壳机参数优化响应面法

维普期刊数据库博看期刊

一种融合注意力机制的形变LSTM智能代码补全方法

在线全文

学校读者我要写书评

暂无评论

小型微型计算机系统 2024年第2期45卷 498-504页

作者：张钦郑尚邹海涛于化龙高尚江苏科技大学计算机学院江苏镇江212100

代码补全(code completion)通过提供类名和方法名等预测,辅助开发人员编写代码,是自动化软件开发的重要功能之一.近年来,智能代码补全已成为软件工程领域的热门研究方向之一,前人工作表明通过自然语言技术或神经网络学习代码,能够提高... 详细信息

代码补全(code completion)通过提供类名和方法名等预测,辅助开发人员编写代码,是自动化软件开发的重要功能之一.近年来,智能代码补全已成为软件工程领域的热门研究方向之一,前人工作表明通过自然语言技术或神经网络学习代码,能够提高代码补全的准确率,但这些补全模型仍存在不足,如代码上下文的信息表示较弱、程序信息提取不全和代码补全任务不平衡.因此,本文提出一种全新的智能代码补全方法,其中引入形变的长短记忆网络(Mogrifier-LSTM)和注意力机制增强代码上下文的信息表示,同时利用双向LSTM学习程序的层次结构信息,并设计一种多任务框架自动实现代码补全任务之间的平衡.通过在真实数据集上进行实验,结果表明本文所提方法表现优于主流代码补全方法.

关键词：软件开发代码补全 LSTM 注意力多任务

相变储能单元内拓扑翅片优化及其传热特性研究

在线全文

学校读者我要写书评

暂无评论

西安交通大学学报 2024年第7期58卷 62-72页

作者：甄华龙张胜棋刘运生蒲亮西安交通大学能源与动力工程学院西安710049 江西卓超科技有限公司江西新余338000

为提升管壳式相变储能单元的蓄放热速率,采用基于变密度法的拓扑优化方法,对二维相变储能单元的翅片进行优化,设计了体积比(翅片体积占设计域体积比)分别为0.1、0.15、0.2的导热拓扑翅片;同时考虑液体流动,设计了体积占比分别为0.1、0.1... 详细信息

为提升管壳式相变储能单元的蓄放热速率,采用基于变密度法的拓扑优化方法,对二维相变储能单元的翅片进行优化,设计了体积比(翅片体积占设计域体积比)分别为0.1、0.15、0.2的导热拓扑翅片;同时考虑液体流动,设计了体积占比分别为0.1、0.15、0.2的对流拓扑翅片。基于上述翅片构型,采用数值模拟方法,对比研究了分别使用拓扑翅片和矩形翅片的相变储能单元的蓄放热特性,分析了使用不同体积占比的拓扑翅片的蓄放热过程。研究表明:在蓄热过程中,使用体积占比为0.15的导热拓扑翅片和对流拓扑翅片的相变储能单元蓄热速率较矩形翅片分别提升了11.5%、33.0%,对流拓扑翅片由于考虑了蓄热过程中相变材料的自然对流效应,其性能优于相同体积占比的导热拓扑翅片;在放热过程中,导热拓扑翅片由于翅片分布较均匀、与相变材料接触区域大,其性能优于相同体积占比的对流拓扑翅片,其中体积占比为0.15的导热拓扑翅片构型综合性能最优。该研究为翅片设计提供了有效支撑,对推动拓扑优化在相变储能单元内的实际应用具有重要价值。

关键词：相变储能拓扑优化翅片构型自然对流

适用于直流链式储能的电池簇荷电状态自均衡控制策略

在线全文

学校读者我要写书评

暂无评论

电力系统自动化 2024年第2期48卷 159-166页

作者：张文昕赵志勇于华龙王继慷赵志芳韩峰北京四方继保自动化股份有限公司北京市100085

电池储能系统凭借其可提高可再生能源消纳能力的优势逐渐成为电网关键环节,其中的生产、使用环节导致的电池不一致性是影响储能系统容量和寿命的重要因素。在直流型高压级联链式储能的拓扑结构基础上采取分级控制策略,基于电压模式和功... 详细信息

电池储能系统凭借其可提高可再生能源消纳能力的优势逐渐成为电网关键环节,其中的生产、使用环节导致的电池不一致性是影响储能系统容量和寿命的重要因素。在直流型高压级联链式储能的拓扑结构基础上采取分级控制策略,基于电压模式和功率模式的一级控制,针对链式电池储能系统电池荷电状态(SOC)不均衡的问题,提出了一种控制参数自适应的SOC自均衡控制策略。该策略综合考虑电池SOC偏差、各模块电容电压水平、直流系统电压控制裕度以及输出调制比上下限,实时计算均衡系数。实验结果验证了所提策略能够在SOC偏差较大以及满功率充放电切换的极端工况下,实现SOC自均衡,均衡效率较高。

关键词：链式变换器变流器电池储能系统荷电状态均衡

在线全文

学校读者我要写书评

暂无评论

基于对象模型的煤矿数据采集融合共享系统

工矿自动化 2024年第1期50卷 17-24,34页

作者：尚伟栋王海力张晓霞王浩徐华龙山西天地王坡煤业有限公司山西晋城048021 煤炭科学研究总院有限公司矿山大数据研究院北京100013 煤炭科学技术研究院有限公司北京100013

针对目前煤矿数据采集、融合与共享存在的设备属性缺乏标准化且语义不统一、数据采集规约无法跨操作系统、数据访问实时性差、数据共享效率低等问题,设计了一种基于对象模型的煤矿数据采集融合共享系统。在基于位号的煤矿数据编码标准... 详细信息

针对目前煤矿数据采集、融合与共享存在的设备属性缺乏标准化且语义不统一、数据采集规约无法跨操作系统、数据访问实时性差、数据共享效率低等问题,设计了一种基于对象模型的煤矿数据采集融合共享系统。在基于位号的煤矿数据编码标准的基础上设计设备对象模型,克服了设备属性缺少标准化和设备属性语义不统一的问题;采用工业规约采集、Restful API问答式采集和文件数据采集等数据接入方式,可支持国产化操作系统,提供了方便的报文监视工具,能够准确判断通信异常原因;通过设备对象模型映射实现数据融合,引入数据治理机制确保数据的准确性和一致性,以对象模型的形式存储数据来节省存储空间、提高存储效率;将所有设备对象数据存储到一张表中,对象化的数据共享接口可简化成实时数据共享接口和历史数据共享接口,减少了冗余接口,从而降低了数据访问次数。应用结果表明,该系统在对设备数据标准化后降低了数据使用过程中语义解析的难度,同时提高了数据的计算、存储和访问性能,为大数据分析提供了保障。

关键词：数据采集数据融合数据共享对象模型数据编码数据治理数据存储