检索结果-南通市图书馆

Journal of Computational Mathematics 2024年第3期42卷 705-734页

作者： Tao Sun chengjian zhang Haiwei Sun School of Mathematics and Statistics Huazhong University of Science and TechnologyWuhan 430074China Hubei Key Laboratory of Engineering Modeling and Scientific Computing Huazhong University of Science and TechnologyWuhan 430074China Department of Mathematics University of MacaoMacaoChina

This paper deals with numerical methods for solving one-dimensional(1D)and twodimensional(2D)initial-boundary value problems(IBVPs)of space-fractional sine-Gordon equations(SGEs)with distributed delay.For 1D problems,we construct a kind of oneparameter finite difference(OPFD)method.It is shown that,under a suitable condition,the proposed method is convergent with second order accuracy both in time and space.In implementation,the preconditioned conjugate gradient(PCG)method with the Strang circulant preconditioner is carried out to improve the computational efficiency of the OPFD method.For 2D problems,we develop another kind of OPFD method.For such a method,two classes of accelerated schemes are suggested,one is alternative direction implicit(ADI)scheme and the other is ADI-PCG scheme.In particular,we prove that ADI scheme can arrive at second-order accuracy in time and space.With some numerical experiments,the computational effectiveness and accuracy of the methods are further verified.Moreover,for the suggested methods,a numerical comparison in computational efficiency is presented.

关键词： Fractional sine-Gordon equation with distributed delay One-parameter finite difference methods Convergence analysis ADI scheme PCG method

Influence of nano-mechanical evolution of Ti_(3)AlC_(2) ceramic on the arc erosion resistance of Ag-based composite electrical contact material

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 Advanced Ceramics 2024年第2期13卷 176-188页

作者： Xuelian Wu Chengzhe Wu Xinpeng Wei Wanjie Sun chengjian Ma Yundeng zhang Gege Li Liming Chen Dandan Wang Peigen zhang Zhengming Sun Jianxiang Ding School of Materials Science and Engineering Anhui University of TechnologyMa’anshan 243032China Analytical and Testing Center Yancheng Institute of TechnologyYancheng 224051China School of Materials Science and Engineering Changzhou UniversityChangzhou 213164China Jiangsu Key Laboratory of Advanced Metallic Materials School of Materials Science and EngineeringSoutheast UniversityNanjing 211189China

Al-containing MAX phase ceramic has demonstrated great potential in the field of high-performance low-voltage electrical contact material.Elucidating the anti-arc erosion mechanism of the MAX phase is crucial for further improving performance,but it is not well-understood.In this study,Ag/Ti_(3)AlC_(2) electrical contact material was synthesized by powder metallurgy and examined by nanoindentation techniques such as constant loading rate indentation,creep testing,and continuous stiffness measurements.Our results indicated a gradual degradation in the nano-mechanical properties of the Ti_(3)AlC_(2) reinforcing phase with increasing arc erosion times,although the rate of this degradation appeared to decelerate over arc erosion times.Specifically,continuous stiffness measurements highlighted the uneven mechanical properties within Ti_(3)AlC_(2),attributing this heterogeneity to the phase’s decomposition.During the early(1-100 times)and intermediate(100-1000 times)stages of arc erosion,the decline in the nano-mechanical properties of Ti_(3)AlC_(2) was primarily ascribed to the decomposition of Ti_(3)AlC_(2) and limited surface oxidation.During the later stage of arc erosion(1000-6200 times),the inner region of Ti_(3)AlC_(2) also sustained arc damage,but a thick oxide layer formed on its surface,enhancing the mechanical properties and overall arc erosion resistance of the Ag/Ti_(3)AlC_(2).

关键词： MAX phase nano-mechanical properties decomposition surface oxidation anti-arc erosion mechanism

From oxygenated monomers to well-defined low-carbon polymers

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 Chemical Letters 2024年第1期35卷 40-44页

作者： Yanni Xia chengjian zhang Yong Wang Shunjie Liu Xinghong zhang National Key Laboratory of Biobased Transportation Fuel Technology International Research Center for X PolymersDepartment of Polymer Science and EngineeringZhejiang UniversityHangzhou 310027China School of Chemistry and Chemical Engineering Huazhong University of Science and TechnologyWuhan 430074China Key Laboratory of Polymer Ecomaterial Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering Hangzhou 310027China

The synthesis of degradable polymers with easy-to-break in-chain carbon-oxygen bonds has attracted much attention.This minireview introduces the synthesis of a variety of degradable polymers from the(co)polymerizations of several typical oxygenated monomers such as epoxides,cyclic carbonates,cyclic esters,carbon dioxide(CO_(2)),carbonyl sulfide(COS),and cyclic anhydrides.We highlight the catalysts and mechanisms for these(co)polymerizations.The ring-opening copolymerization of five-membered carbonate with cyclic anhydride or COS has been introduced.We also highlight the synthesis of block copolymers and cyclic copolymers with well-defined sequences by the method of growing center switching.We hope that these new polymerization systems can provide new ideas for the development of degradable low-carbon polymers in the future.

关键词： Polymer synthesis Degradable polymer Low-carbon polymer Catalysis Ring-opening polymerization

Key progresses of MOE key laboratory of macromolecular synthesis and functionalization in 2022

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2024年第3期35卷 114-126页

作者： Xumeng Deng Kaihao Chen Kai Pang Xiaoting Liu Minsong Gao Jie Ren Guanwen Yang Guangpeng Wu chengjian zhang Xufeng Ni Peng zhang Jian Ji Jianzhao Liu Zhengwei Mao Ziliang Wu Zhen Xu Haoke zhang Hanying Li MOE Key Laboratory of Macromolecular Synthesis and Functionalization International Research Center for X PolymersDepartment of Polymer Science and EngineeringZhejiang UniversityHangzhou 310027China

In 2022,The MOE Key Laboratory of Macromolecular Synthesis and Functionalization in Zhejiang University had achieved several important results.First,a series of well-defined dinuclear organoboron catalysts were developed to precisely control the enchainment of ether and carbonate segments during the copolymerization of CO_(2)and epoxides.Second,polyester had been synthesized through cationic copolymerization of cyclic anhydride.Third,ring-opening polymerization of carbon dioxide based valerolactone had been achieved,revealing the prospect of 3-ethylidene-6-vinyltetrahydro-2H-pyran-2-one(EVL)in utilizing CO_(2)and synthesizing functional polymers.Fourth,machine learning methods have been applied to biomaterial research,enabling high-throughput screening of functional biomaterial surfaces for implantable devices,and searching for potent antimicrobial peptides in whole combinatorial peptide libraries.Fifth,methods of characterization of biomacromolecule RNA transcription and manipulation of nucleoside modification were developed.Sixth,artificial enzymes-armed Bifidobacterium Longum probiotics were established to tune down gut inflammation.Seventh,three-dimensional(3D)printing technologies were used to engineer tough supramolecular hydrogels.Eighth,hydroplastic foaming graphene frameworks for acoustic and conductive polymer composites were provided for application.Ninth,aggregate photophysics about the nature of through-space interactions(TSIs)and manipulating their strength in small molecules with non-conjugated structure had been elucidated.Tenth,the forming mechanism of a newfound nested texture in poly(L-lactic acid)(PLLA)spherulitic films had been revealed.Finally,the isotropically dyeing mechanism of KDP single crystals grown from hydrogels have been explored.The related works are reviewed in this paper.

关键词： Polymer Catalyst Biomaterial research mRNA Hydrogel Graphene Crystal

Oxygen/Sulfur Atom Exchange Copolymerization of Carbon Disulfide and Propylene Oxide by a Highly Effective Heterogeneous Berlin Green Catalyst

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2023年第5期39卷 790-796页

作者： Munir Ullah KHAN Safir Ullah KHAN CAO Xiaohan Muhammad USMAN Muhammad Naeem SHAH Abdul GHAFFAR Muhammad HASSAN zhang chengjian zhang Xinghong State Key Laboratory of Motor Vehicle Biofuel Technology International Research Center for X PolymersDepartment of Polymer Science and EngineeringZhejiang UniversityHangzhou 310027P.R.China Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering Shanxi 030013P.R.China Hefei National Laboratory for Physical Science at the Microscale School of Life SciencesUniversity of Science and Technology of ChinaHefei 230027P.R.China Key Laboratory of Macromolecular Synthesis and Functionalization(Ministry of Education) International Research Center for X PolymersDepartment of Polymer Science and EngineeringZhejiang UniversityHangzhou 310027P.R.China College of Information Science and Electronic Engineering Zhejiang UniversityHangzhou 310027P.R.China Advanced Materials Research Center Zhejiang University-University of Illinois at Urbana-Champaign Institute(ZJU-UIUC)Haining 314400P.R.China

In this study,we report that Berlin Green(FeFe-BG)framework exhibits superior performance in the catalytic coupling of carbon disulfide(CS_(2))and propylene oxide(PO)to generate a random copolymer containing thioether,propylene monothiocarbonate and ether units.Oxygen and sulfur atom exchange was detected in polymeric and cyclic thiocarbonate byproducts and utilized to modulate the copolymerization of CS_(2)and propylene oxide.The coupling of PO and CS_(2)was selective for copolymer formation under various reaction conditions.^(1)H and^(13)C NMR spectroscopy determined two distinct polymer linkages and two cyclic byproducts.Copolymer number average molecular weights ranged from 6.4 kg/mol to 10.5 kg/mol,with a comparatively low polydispersity of 1.3-1.7.The CS_(2)/PO molar feed ratio had a significant impact on the O/S exchange process;the ratio of cyclic thiocarbonate byproducts could be efficiently regulated by tuning the CS_(2)molar feed ratio.

关键词： Carbon disulfide Copolymerization Prussian Blue analogue Heterogeneous catalysis Berlin Green

基于德尔菲法和层次分析法构建健康企业评价指标体系的研究

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

中华劳动卫生职业病杂志 2024年第2期42卷 112-117页

作者：朱嫒嫒曹承建张磊李金涛傅红朱康钱宝杭州市职业病防治院医教科杭州310014 杭州市职业病防治院院长室杭州310014 杭州市健康城市指导中心健康城市评价科杭州310000 杭州市职业病防治院职业卫生科杭州310014 杭州师范大学公共卫生学院杭州310000

目的探索应用德尔菲(Delphi)法和层次分析法探索构建科学、客观、全面的健康企业建设评价指标体系,推动健康企业建设。方法于2022年10月,通过德尔菲专家咨询法和层次分析法,筛选指标并确定指标的权重,建立健康企业评价指标体系。结果两... 详细信息

目的探索应用德尔菲(Delphi)法和层次分析法探索构建科学、客观、全面的健康企业建设评价指标体系,推动健康企业建设。方法于2022年10月,通过德尔菲专家咨询法和层次分析法,筛选指标并确定指标的权重,建立健康企业评价指标体系。结果两轮专家积极系数均为100.00%,专家权威系数为0.82,两轮指标的变异系数均<0.30,第一轮和第二轮专家协调系数分别为0.64和0.77(P<0.001)。经过两轮德尔菲法专家咨询,构建了包含4个一级指标、14个二级指标、63个三级指标的健康企业评价指标体系。结论构建的健康企业评价指标体系具有较高的科学性和可靠性,涵盖健康企业建设的主要因素,为健康企业创建提供可靠、可量化的依据和自评依据。

关键词：职业健康企业德尔菲法健康企业指标体系层次分析法

在线全文

学校读者我要写书评

暂无评论

《涉过愤怒的海》学术研讨会发言摘要

北京电影学院学报 2024年第1期 85-99页

作者： Cao Baoping Rao Shuguang Huangfu Yichuan Chen Xuguang Li Yang zhang Wei Zhong Dafeng Sun chengjian Zuo Heng Sai Ren Hu Jianli Li Xingwen 不详

2024年1月5日,影片《涉过愤怒的海》学术研讨会在北京电影学院海淀校区召开。研讨会由北京电影学院中国电影文化研究院执行院长、《北京电影学院学报》主编吴冠平教授主持。曹保平导演及各位专家学者分别从创作、学术以及票房市场等多... 详细信息

2024年1月5日,影片《涉过愤怒的海》学术研讨会在北京电影学院海淀校区召开。研讨会由北京电影学院中国电影文化研究院执行院长、《北京电影学院学报》主编吴冠平教授主持。曹保平导演及各位专家学者分别从创作、学术以及票房市场等多个角度阐发了各自的观点。

关键词：北京电影学院曹保平《北京电影学院学报》发言摘要中国电影文化学术研讨会愤怒票房

在线全文

学校读者我要写书评

暂无评论

一种骨折断端压力测量调节装置的设计与测试

中国医疗器械杂志 2024年第3期48卷 335-338页

作者：沈忠愿范逸哲章晓韩真魏成建南京中医药大学第一临床医学院南京市210023 南京中医药大学附属医院骨伤科南京市210029

目的设计一种能够准确测量并动态调节骨折断端轴向压力的装置,并进行测试。方法设计完成后的压力测量调节装置被应用于比格犬的胫骨骨折外固定模型中。在骨折断端处安装了压力传感器,将压力传感器的显示值作为标准值,比较了在相同条件下... 详细信息

目的设计一种能够准确测量并动态调节骨折断端轴向压力的装置,并进行测试。方法设计完成后的压力测量调节装置被应用于比格犬的胫骨骨折外固定模型中。在骨折断端处安装了压力传感器,将压力传感器的显示值作为标准值,比较了在相同条件下,测量调节装置的显示数值与压力传感器显示的压力数值之间的关系。结果该装置在5只比格犬的胫骨骨折外固定模型中得到了应用,结果显示装置的显示数值与骨折断端压力传感器的数值之间存在线性关系。通过系数转换,该装置的测量数值可以准确反映骨折断端的压力,从而实现了骨折断端压力的准确测量与动态调节。结论该骨折断端压力测量调节装置操作简便,能准确测量并动态调整骨折断端的压力值,适用于进行动物实验,以探究轴向加压对骨折愈合的影响,具有广阔的实验应用前景。

关键词：骨折断端轴向加压压力动态测量调节

在线全文

学校读者我要写书评

暂无评论

基于cosRMC的同位素电池屏蔽计算研究

原子能科学技术 2024年第3期58卷 622-629页

作者：王益祺刘仕倡靳程建李锐孙宁延韩毅张显陈义学华北电力大学核科学与工程学院北京102206 中国辐射防护研究院山西太原030006 辐射安全与防护山西省重点实验室山西太原030006

热电式同位素电池系统作为一种新型能源系统,在深空、深海探测任务中有广泛应用。钛酸锶热源中的放射性同位素90 Sr和90 Y会发射β射线,β射线与物质作用产生韧致辐射,韧致辐射具有很强的穿透力,需要为热源安装屏蔽层,以降低辐射剂量。... 详细信息

热电式同位素电池系统作为一种新型能源系统,在深空、深海探测任务中有广泛应用。钛酸锶热源中的放射性同位素90 Sr和90 Y会发射β射线,β射线与物质作用产生韧致辐射,韧致辐射具有很强的穿透力,需要为热源安装屏蔽层,以降低辐射剂量。当屏蔽层厚度超过一定值后,蒙特卡罗方法计算结果的统计误差显著增大,采用减方差技术可以提高热电式同位素电池屏蔽计算的准确性。同时,直接电子输运模拟耗时很长,可以通过厚靶韧致辐射模型处理电子产生的光子,从而提高计算效率。本文开展了cosRMC程序的减方差技术和厚靶韧致辐射模型在同位素电池屏蔽计算中的应用研究与验证,基于美国SNAP-21结构的设计方案,采用cosRMC程序对同位素电池进行了精细建模,通过改变外屏蔽层厚度分析其对表面剂量率的影响,并与MCNP结果进行比较。结果表明,在电池径向和轴向使用不同厚度的屏蔽层,cosRMC与MCNP计算的贫铀屏蔽层表面的剂量率的相对误差在±3σ区间内符合良好。采用栅元重要性减方差后,两程序统计误差均减小,且在电池径向5 cm处和轴向4 cm处,结果在±3σ区间内符合良好,进一步验证了cosRMC程序进行热电式同位素电池屏蔽计算的准确性。

关键词：同位素电池屏蔽计算 MCNP cosRMC 减方差

SKA3蛋白在胆管癌组织中的表达及其体外对胆管癌SSP-25细胞功能和PI3K-AKT信号通路的影响

在线全文

学校读者我要写书评

暂无评论

肿瘤研究与临床 2024年第5期36卷 335-340页

作者：汪栋张轶西管成剑张小东林华骏郭伟首都医科大学附属北京友谊医院普通外科北京100050

目的探讨胆管癌组织中SKA3蛋白的表达和临床意义,以及体外干扰SKA3表达对胆管癌SSP-25细胞增殖、侵袭和迁移的影响和可能机制。方法回顾性收集2015年1月至2020年12月首都医科大学附属北京友谊医院172例远端胆管癌患者临床病理资料及癌... 详细信息

目的探讨胆管癌组织中SKA3蛋白的表达和临床意义,以及体外干扰SKA3表达对胆管癌SSP-25细胞增殖、侵袭和迁移的影响和可能机制。方法回顾性收集2015年1月至2020年12月首都医科大学附属北京友谊医院172例远端胆管癌患者临床病理资料及癌组织、癌旁组织标本。采用免疫组织化学法检测癌组织和癌旁组织中SKA3蛋白的表达水平。向胆管癌SSP-25细胞转染SKA3小干扰RNA(siRNA)(si-SKA3组),以未经处理的SSP-25细胞为对照组。采用细胞免疫荧光染色和蛋白质印迹法检测转染效果;采用CCK-8法和细胞集落形成实验观察细胞增殖变化;采用细胞划痕实验检测细胞侵袭能力;采用蛋白质印迹法检测PI3K-AKT信号通路相关蛋白的表达情况。结果172例胆管癌患者中,男性116例,女性56例;年龄0.05)。CCK-8法检测示,培养72 h si-SKA3组SSP-25细胞增殖能力(以450 nm处吸光度值表示)低于对照组(0.56±0.05比0.83±0.06),差异有统计学意义(t=3.06,P=0.006)。集落形成实验显示,培养2周后si-SKA3组SSP-25细胞集落形成数少于对照组。培养24 h,si-SKA3组和对照组SSP-25细胞划痕愈合率分别为(31±6)%、(72±5)%,差异有统计学意义(t=5.63,P=0.013)。蛋白质印迹法检测显示,PI3K-AKT信号通路中p-PI3K、p-AKT蛋白相对表达量均低于对照组,差异均有统计学意义(均P<0.05)。结论胆管癌组织中SKA3蛋白高表达,与神经侵犯、淋巴结转移可能相关。干扰SKA3表达可抑制胆管癌SSP-25细胞的增殖和侵袭,其机制可能与抑制PI3K-AKT信号通路有关。

关键词：胆管肿瘤 SKA3蛋白细胞增殖肿瘤侵润 PI3K-AKT信号通路