检索结果-南通市图书馆

Optical Transient Source AT2021lfa:A Possible“Dirty Fireball”

Research in Astronomy and Astrophysics 2024年第4期24卷 124-133页

作者： Xue-Mei Ye Da-ming Wei yi-ming zhu Zhi-Ping Jin Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210023China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China National Astronomical Observatories/Nanjing Institute of Astronomical Optics&Technology Chinese Academy of SciencesNanjing 210042China CAS Key Laboratory of Astronomical Optics&Technology Nanjing Institute of Astronomical Optics&TechnologyNanjing 210042China

AT2021lfa,also known as ZTF21aayokph,was detected by the Zwicky Transient Facility on 2021 May 4,a 05:34:48 ***-up observations were conducted using a range of ground-based optical telescopes,as wel as Swift/XRT and VLA ***2021lfa is classified as an“orphan afterglow”candidate due to its rapid flux decline and its reddened color(g-r=0.17±0.14 mag).For an optical transient source without promp gamma-ray detection,one key point is to determine its burst *** we measure the burst time through fitting the initial bump feature of AT2021lfa and obtain its burst time as 2021 May 3,at 22:09:50 *** afterglowpy,we model the multi-band afterglow of AT2021lfa and find that the standard model canno reproduce the late radio observations *** that the microphysical parameters ε_(e),ε_(B)(the energy fraction given to electrons and magnetic field),andξN(the fraction of accelerated electrons)may vary with time we then model the afterglow of AT2021lfa taking into account the temporal evolution of the physical parameters ε_(e),ε^(B),and ξ_(N) and find in this case the multi-wavelength observations can be reproduced *** initial Lorentz factor of AT2021lfa can be estimated from the peak time of the early afterglow,which yields a value of about 18 suggesting that AT2021lfa should be classified as a“dirty fireball.”From the upper limit for the prompt emission energy of AT2021lfa,we obtain that the radiation efficiency is less than 0.02%,which is much smaller than that of ordinary gamma-ray bursts(GRBs).It is also interesting that the fitted values of jet angle and viewing angle are very large,θ_(c)~0.66 rad,θ_(v)~0.53 rad,which may lead to the low Lorentz factor and radiation *** compared with GRB afterglow samples,it is evident that the onset bump timescale of AT2021lfa satisfies the empirical relationships observed in GRB ***,the luminosity of AT2021lfa falls within the range of observations for GRB samples;howeve

关键词： gamma-rays:ISM methods:numerical radiation mechanisms:non-thermal

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Isocyanide-Based One-Pot Cascade Synthesis of 3-Acyl Isoindolinones

引用

Chinese Journal of Chemistry 2024年第3期42卷 259-263页

作者： Jia Liu yi-ming zhu Xiao-Ping Xu Shun-Jun Ji Key Laboratory of Organic Synthesis of Jiangsu Province College of ChemistryChemical Engineering and Materials Science & Collaborative Innovation Center of Suzhou Nano Science and TechnologySoochow UniversitySuzhouJiangsu215123 China Suzhou Baolidi Functional Materials Research Institute SuzhouJiangsu215144 China

A series of 3-acyl-substituted isoindolinone derivatives were synthesized in a one-pot manner via the reaction of o-bromobenzaldehydes,isocyanides,and carboxylic acids in the presence of palladium catalyst and base. The reaction employing easily available starting materials features simple operation and high efficiency. The mechanistic study showed that the reaction might undergo 1) Pd-catalyzed [3+2] cyclization of o-bromobenzaldehyde with isocyanide and the re-insertion of another molecule of isocyanide,2) addition of carboxylic acid to in situ formed ketenimine followed by a rearrangement relay to give 3,3-diacyl-substituted isoindolinone derivative. Further transformations of the obtained products through decarbonylation could also be realized.

关键词： One-pot reaction Isocyanide Pd catalysis Rearrangement reaction Isoindolinone

来源：

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

Cooperative enhancement of mechanical and tribological properties through tailoring TiN transition interface in boron nitride nanosheets reinforced copper composites

引用

Rare Metals 2024年第10期43卷 5202-5215页

作者： Zhong-Hua Li Liang Liu Xin You Jian-Hong yi Rui Bao ming-yi zhu Song Lu Jun-Jun Pai Faculty of Materials Science and Engineering Kunming University of Science and Technology Key Laboratory of Advanced Materials of Yunnan Province Kunming University of Science and Technology

Strengthening interface bonding between boron nitride nanosheets(BNNS) and copper matrix is an essential prerequisite for exploiting a new generation of copper matrix composites(CMCs) with high strength and wear resistance. Herein, BNNS/Cu composites were fabricated by the powder metallurgy route, matrix-alloying(adding 1.0 wt% Ti) strategy was adopted to improve the interfacial wettability and strengthen interface adhesion. A typical "sandwich"-like multiply interface structure involving TiN transition layers, BNNS and Cu matrix had been well constructed through the rational heat treatment(900℃for 120 min). Additionally, nano-sized TiB whisker was in situ formed in the vicinity of the interface, it had linked the BNNS-Cu-TiN multiply interface, which played a role of "threading the needle" and significantly strengthened the multi-interfaces bonding. This specific interface structure was finely characterized, and the formation mechanism of solid-state interfacial reaction feature was proposed. The results demonstrated that the ultimate tensile strength(UTS) of BNNS/Cu-(Ti)-900℃ increased from 248 to 530 MPa(increased by 114%), and the coefficient of friction(COF) decreased from 0.51 to 0.28 than pure Cu. This work highlights the importance of interface configuration design, which contributes to the development of CMCs with prominent comprehensive properties.

关键词： Boron nitride nanosheets Copper matrix composites Interface structure Mechanical and frictional properties

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Mn(Ⅲ)-mediated radical reaction of 2-isocyano-6-alkenyl(alkynyl)benzonitriles with arylboronic acids:Synthesis of pyrroloisoquinoline derivatives

引用

Chinese Chemical Letters 2021年第1期32卷 413-416页

作者： Pei Xu yi-ming zhu Xin-Yu Liu Xiao-Zhou Zhou Shun-yi Wang Shun-Jun Ji Key Laboratory of Organic Synthesis of Jiangsu Province College of ChemistryChemical Engineering and Materials Science&Collaborative Innovation Center of Suzhou Nano Science and TechnologySoochow UniversitySuzhou 215123China

A Mn(Ⅲ) mediated radical reaction of new designed multi-functionalized 2-isocyano-6-alkenyl(alkynyl)benzonitriles with arylboronic acids has been *** reaction provides a method for the synthesis of pyrroloisoquinolin... 详细信息

关键词： 2-Isocyano-6-alkenyl(alkynyl)benzonitriles Arylboronic acids Pyrroloisoquinoline derivatives Radical reaction

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Photoproduction reactionγn→K^(*0)∧in an effective Lagrangian approach

引用

Chinese Physics C 2022年第2期46卷 57-61页

作者： Neng-Chang Wei yi-ming zhu Fei Huang School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 101408China School of Physical Sciences University of Chinese Academy of SciencesBeijing 101408China

In our previous work[***.C 101,014003(2020)],the photoproduction reactionγp→K^(*+)Λwas investigated within an effective Lagrangian *** reaction amplitudes were constructed by including the t-channel K,K^(*),and k exchanges,u-channelΛ,∑,and∑^(*)exchanges,s-channel N,N(2000)5/2^(+),and N(2060)5/2^(-)exchanges,and interaction *** data on the differential cross sections and spin density matrix elements were described *** this study,we investigate the photoproduction reactionγn→K^(*0)Λbased on the same reaction mechanism as that ofγp→K^(*+)Λto obtain a unified description of the data forγp→K^(*+)Λandγn→K^(*0)Λwithin the same *** hadronic coupling constants,form factor cutoffs,and the resonance masses and widths in the present calculations remain the same as in our previous work forγp→K^(*+)Λ.The available differential cross-section data forγn→K^(*0)Λare well *** analysis shows that the cross sections ofγn→K^(*0)Λare dominated by the contributions of the t-channel K exchange,while the s-channel N(2000)5/2+and N(2060)5/2-exchanges also provide considerable contributions.

关键词： photoproduction effective Lagrangian approach gauge invariance

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Resonances Characteristics of Parallel Plate Waveguide Cavities

引用

Journal of Electronic Science and Technology 2015年第2期13卷 122-129页

作者： Lin Chen Dan-Ni Wang yi-ming zhu Yan Peng Shanghai Key Lab of Modern Optical System Engineering Research Center of Optical Instrument and SystemMinistry of EducationUniversity of Shanghai for Science and Technology

The influence of air gaps on the response of transmission for a transverse-electric mode parallel-plate waveguide（TE-PPWG） with a single cavity and double cavities has been studied experimentally. As the air gap is larger than the resonant wavelength of high order cavity mode in the single deep grooved waveguide, only the fundamental cavity mode can be excited and single resonance can be observed in the transmission spectrum. Based on above observations, a tunable multiband terahertz（THz）notch filter has been proposed and the variation of air gap has turned out to be an effective method to select the band number. Experimental data and simulated results verify this band number tunability. This mechanical control mechanism for electromagnetic induced transparency（EIT） will open a door to design the tunable THz devices.

关键词： resonant transparency excited waveguide tunable terahertz verify notch realization optics

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

氢燃料电池用气浮离心空压机实验与模拟研究

引用

风机技术 2024年第3期66卷 29-34页

作者：李栋王琪杨山举张丽君祝艺鸣朱学卫西北农林科技大学机械与电子工程学院

气浮轴承离心空压机具有无油、高效、低成本、轻量化和动态响应性好等优点,已成为车载氢燃料电池空压机的最佳选择。本文介绍了自主研发的额定压比2.8、质量流量130g/s、转速88000r/min、功率22kW的两级气浮轴承离心空压机,用于匹配电... 详细信息

气浮轴承离心空压机具有无油、高效、低成本、轻量化和动态响应性好等优点,已成为车载氢燃料电池空压机的最佳选择。本文介绍了自主研发的额定压比2.8、质量流量130g/s、转速88000r/min、功率22kW的两级气浮轴承离心空压机,用于匹配电堆功率130kW的车载氢燃料电池。在离心空压机气动性能试验台上测试了空压机在60000~95000r/min范围内的气动性能,同时构建了离心空压机的泄漏通流模型并对其进行了数值模拟,最后将模拟结果与实验数据进行了对比分析。研究结果表明,该离心空压机在实验时最大转速达95000r/min,最大绝热效率可达77.04%。

关键词：氢燃料电池离心空压机箔片动压气浮轴承实验研究泄漏通流模型可靠性

来源：

维普期刊数据库

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Photocatalytic in situ H_(2)O_(2) production and activation for enhanced ciprofloxacin degradation over CeO_(2)-Co_(3)O_(4)/g-C_(3)N_(4):key role of CeO_(2)

引用

Rare Metals 2024年第6期43卷 2695-2707页

作者： Hong-Jie zhu yi-Kai Yang ming-Hui Li Lu-Ning Zou Hai-Tao Zhao Shandong Provincial Key Laboratory of Chemical Energy Storage and Novel Cell Technology School of Chemistry and Chemical Engin College of Ecology and Environment Anhui Normal UniversityWuhu241002China Liaocheng yiLu Advanced Materials Co. LtdLiaocheng 252000China

The abused ciprofloxacin antibiotics have caused significant environmental *** oxidative degradation of ciprofloxacin exhibits promising efficacy,it often entails excessive energy ***,it is necessary to explore an effective and ecologically sustainable degradation ***,we demonstrated that g-C_(3)N_(4) decorated with the coordinated CeO_(2)and Co_(3)O_(4)(CeO_(2)-Co_(3)O_(4)/CN)exhibited effective ciprofloxacin photodegradation via in situ H_(2)O_(2) production and activation *** indicate that the introduced CeO_(2) enhances the transference of photogenerated electrons to O_(2) by adjusting the oxygen vacancy of photocatalyst,thereby increasing the generation of superoxide radicals,which in turn generate H_(2)O_(2),resulting in a 22.4-fold increase in H_(2)O_(2) generation over g-C_(3)N_(4).Moreover,the in situ H_(2)O_(2)generation facilitated by CeO_(2) is confirmed to be essential for ciprofloxacin degradation via CeO_(2)-Co_(3)O_(4)/CN,as it provides enough oxidant for Co_(3)O_(4) to activate into hydroxyl radicals for the pollutants ***,CeO_(2)-Co_(3)O_(4)/CN achieves a ciprofloxacin degradation ratio of 97.7%within 80 *** study introduces a novel approach that combines H_(2)O_(2) generation and activation,offering an innovative perspective for achieving clean and efficient purification of antibiotic-contaminated water.

关键词： CeO_(2) In situ H_(2)O_(2)generation Ciprofloxacin degradation Photocatalyst

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A solution method for decomposing vector fields in Hamilton energy

引用

Chinese Physics B 2024年第9期33卷 645-653页

作者： Xin Zhao ming yi Zhou-Chao Wei Yuan zhu Lu-Lu Lu School of Mathematics and Physics China University of GeosciencesWuhan 430074China

Hamilton energy,which reflects the energy variation of systems,is one of the crucial instruments used to analyze the characteristics of dynamical *** we propose a method to deduce Hamilton energy based on the existing *** derivation process consists of three steps:step 1,decomposing the vector field;step 2,solving the Hamilton energy function;and step 3,verifying *** order to easily choose an appropriate decomposition method,we propose a classification criterion based on the form of system state variables,i.e.,type-I vector fields that can be directly decomposed and type-II vector fields decomposed via exterior ***,exterior differentiation is used to represent the curl of low-high dimension vector fields in the process of ***,we exemplify the Hamilton energy function of six classical systems and analyze the relationship between Hamilton energy and dynamic *** solution provides a new approach for deducing the Hamilton energy function,especially in high-dimensional systems.

关键词： Hamilton energy dynamical systems vector field exterior differentiation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A Self-Healing Elastomer with Extremely High Toughness Achieved by Acylsemicarbazide Hydrogen Bonding and Cu^(2+)-Neocuproine Coordination Interactions

引用

Chinese Journal of Polymer Science 2024年第10期42卷 1425-1434,I0007页

作者： Xiao-ming An yi-Ping Wang Tang-Song zhu Chong Xing Xu-Dong Jia Qiu-Hong Zhang Key Laboratory of High Performance Polymer Material and Technology of MOE Department of Polymer Science and EngineeringSchool of Chemistry and Chemical EngineeringNanjing UniversityNanjing210093China State Key Laboratory of Coordination Chemistry Nanjing UniversityNanjing210093China

Elastomers with high mechanical toughness can guarantee their durability during service ***-healing ability,as well as recyclability,can also extend the life of materials and save the consuming cost of the *** efforts have been dedicated to promoting the mechanical toughness as well as the self-healing capability of elastomers at the same time,while it remains a challenge to balance the trade-off between the above properties in one *** we proposed a molecular design driven by dual interactions of acylsemicarbazide hydrogen bonding and Cu^(2+)-neocuproine coordination *** introducing the reversible multiple hydrogen bonds and strong coordination bonds,we successfully fabricated an extremely tough and self-healing *** elastomer can achieve an impressive top-notch toughness of 491 MJ/m^(3).Furthermore,it boasted rapid elastic restorability within 10 min and outstanding crack tolerance with high fracture energy(152.6kJ/m^(2)).Benefiting from the combination of dynamic interactions,the material was able to self-repair under 80℃conveniently and could be reprocessed to restore the exceptional mechanical properties.

关键词： Metal-ligand coordination Hydrogen bond Ultra-tough elastomer Self-healing

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：