检索结果-南通市图书馆

Mantle geochemistry: Insights from ocean island basalts

Science China Earth Sciences 2017年第11期60卷 1976-2000页

作者： huang shichun ZHENG YongFei Department of Geoscience University of Nevada CAS Key Laboratory of Crust-Mantle Material and Environment School of Earth and Space Sciences University of Science and Technology of China

The geochemical study of the Earth's mantle provides important constraints on our understanding of the formation and evolution of Earth, its internal structure, and the mantle dynamics. The bulk Earth composition is inferred by comparing terrestrial mantle rocks with chondrites, which leads to the chondritic Earth model. That is, Earth has the same relative proportions of refractory elements as that in chondrites, but it is depleted in volatiles. Ocean island basalts(OIB) may be produced by mantle plumes with possible deep origins; consequently, they provide unique opportunity to study the deep Earth. Isotopic variations within OIB can be described using a limited number of mantle endmembers, such as EM1, EM2 and HIMU, and they have been used to decipher important mantle processes. Introduction of crustal material into the deep mantle via subduction and delamination is important in generating mantle heterogeneity; however, there is active debate on how they were sampled by mantle melting, i.e.,the role of olivine-poor lithologies in the OIB petrogenesis. The origin and location of high 3He/4He mantle remain controversial,ranging from unprocessed(or less processed) primitive material in the lower mantle to highly processed materials with shallow origins, including ancient melting residues, mafic cumulates under arcs, and recycled hydrous minerals. Possible core-mantle interaction was hypothesized to introduce distinctive geochemical signatures such as radiogenic 186 Os and Fe and Ni enrichment in the OIB. Small but important variations in some short-lived nuclides, including 142 Nd, 182 W and several Xe isotopes, have been reported in ancient and modern terrestrial rocks, implying that the Earth's mantle must have been differentiated within the first 100 Myr of its formation, and the mantle is not efficiently homogenized by mantle convection.

关键词： Mantle structure Mantle composition Crustal components Crust-mantle interaction Crustal recycling

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

Calcium isotope compositions as a means to trace carbonate recycling

引用

National Science Review 2022年第6期9卷 8-10页

作者： shichun huang Stein B.Jacobsen Department of Geoscience University of Nevada Department of Earth and Planetary Sciences Harvard University

Marine carbonates, such as sedimentary carbonates and secondary carbonates formed during marine alteration processes, are returned to the mantle at subduction zones, and their fates regulate the global carbon cycle. S... 详细信息

关键词： Carbonates

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

Coupled deep-mantle carbon-water cycle: Evidence from lower-mantle diamonds

引用

The Innovation 2021年第2期2卷 47-53页

作者： Wenzhong Wang Oliver Tschauner shichun huang Zhongqing Wu Yufei Meng Hans Bechtel Ho-Kwang Mao Laboratory of Seismology and Physics of Earth’s Interior School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China Department of Geoscience University of Nevada Las VegasLas VegasNV 89154USA CAS Center for Excellence in Comparative Planetology USTCHefeiHefei 230026China Center for High Pressure Science and Technology Advanced Research Shanghai 201203China Advanced Light Source Lawrence Berkeley National LaboratoryBerkeleyCA 94720USA Department of Earth Sciences University College LondonLondon WC1E 6BTUK Earth and Planets Laboratory Carnegie Institution for ScienceWashingtonDC 20015USA

Diamonds form in a variety of environments between subducted crust,lithospheric and deep ***,deep source diamonds with inclusions of the high-pressure H2O-phase ice-VII were *** correlating the pressures of ice-VII inclusions with those of other high-pressure inclusions,we assess quantitatively the pressures and temperatures of their *** show that the iceVII-bearing diamonds formed at depths down to 800±60 km but at temperatures 200–500 K below average mantle temperature that match the pressure-temperature conditions of decomposing dense hydrous mantle *** work presents strong evidence for coupled recycling of water and carbon in the deep mantle based on natural samples.

关键词： diamond deep mantle water and carbon cycle first-principles calculations

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

Individual-level modifiers of the acute effects of air pollution on mortality in Wuhan,China

引用

Global Health Research and Policy 2018年第1期3卷 109-117页

作者： Peirong Zhong shichun huang Xiaotong Zhang Simin Wu Yaohui Zhu Yang Li Lu Ma Department of Healthcare Management School of Health SciencesWuhan University115 Donghu RoadWuchang DistrictWuhan 430071China Hubei Provincial Center for Disease Control and Prevention 6 Zhuodaoquan North RoadHongshan DistrictWuhan 430079China Global Health Institute Wuhan University115 Donghu RoadWuchang DistrictWuhan City 430071China

Background:Ambient air pollution has posed negative effects on human ***-level factors may modify this effect,but previous studies have controversial conclusions,and evidence is lacking especially in developing *** study aims to examine the modifying effects of sex,age,and education level of individuals on the associated between daily mortality and air pollutants,including particulate matter<10μm in aerodynamic diameter(PM_(10)),sulfur dioxide(SO_(2)),and nitrogen dioxide(NO_(2)).Methods:Time-series analysis was conducted to investigate the acute effects of the air pollution on daily mortality from January 2002 to December 2010 in Wuhan,*** Additive Models(GAM)were used to examine the association stratified by sex for non-accidental,cardiovascular,and respiratory *** non-accidental mortality,stratified analysis was also conducted by age and educational ***:Outdoor air pollution was associated with daily non-accidental and cardiovascular *** increase of 10μg/m3 in a 2-day average concentration of PM10,SO_(2),and NO_(2) was corresponding to the increase in non-accidental mortality of 0.29%(95%CI:0.06-0.53%),1.22%(95%CI:0.77-1.67%)and 1.60%(95%CI:1.00-2.19%),*** effects of air pollution were faster in females than *** magnitude of the estimates was higher for females with low education,aged 65-75 years for PM_(10) and<65 years for SO_(2).To be more specific,we observed that per 10μg/m^(3) increase in SO_(2) was association with increases in non-accidental mortality of 2.03%(95%CI:1.38-2.67)for all females and 3.10%(95%CI:2.05-4.16)for females with low ***:Females and people with low-education are more susceptible to the effect of air pollution,which would provide a sound scientific basis for determination of air pollution standards.

关键词： Air pollution Mortality Effect modifiers Susceptible subpopulation

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

Development and Performance of the First Nb_(3)Sn Thin-Film Cavity via Bronze Process

引用

Chinese Physics Letters 2022年第11期39卷 33-36页

作者： Ming Lu Didi Luo Feng Pan Chunlong Li shichun huang Ziqin Yang Andong Wu Qingwei Chu Tongtong Zhu Shuai Wu Teng Tan Hao Guo Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 100049China School of Nuclear Science and Technology Lanzhou UniversityLanzhou 730000China

Low-temperature synthesis of Nb_(3)Sn thin-film cavity is of great significance in the field of superconducting radio frequency(SRF).The bronze process can grow only stable Nb_(3)Sn phase at 700℃,so it is considered to be the most promising process for low-temperature synthesis of Nb3Sn thin-film *** successfully fabricated the worldwide first Nb_(3)Sn thin-film cavity by bronze *** technically solved the key problems of precursor preparation,characterized and analyzed the uniformity of the Nb_(3)Sn film,and tested the performance of the cutout samples and the whole cavity of the Nb_(3)Sn *** is obtained that the Q0value of the cavity at 4.2 K is about 1.2×10^(9),which is greater than the performance of the bulk-niobium cavity under the same *** result means that the preparation of Nb_(3)Sn by bronze process has the great potential to more practical copper-based Nb_(3)Sn thin-film cavity,which is expected to achieve a substantial improvement in the performance of SRF cavity and comprehensive engineering applications.

关键词： Nb_(3)Sn cavity film

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

6-7 Mechanical Design and Fabrication of 162.5 MHz Buncher for C-ADS Injector II

引用

IMP & HIRFL Annual Report 2014年第1期 256-257页

作者： Niu Haihua Zhang Bin Yuan Chenzhang huang shichun Jia Huan Zhang Shenghu 不详

Two room temperature quarter wave resonator（QWR）buncher cavities with frequency of 162.5 MHz havebeen designed as parts of the medium energy beam transport line（MEBT1）for injectorⅡin China AcceleratorDriven Sub-critical System (C-ADS) project in order to focus the beam longitudinally, thus keeping the bunchlength and matching the beam to the acceptance of the superconducting *** is one of major equipments in MEBT1. Fig. 1 shows the layout of the MEBT1. Its structure directlyaffects the performance of MEBT1. Buncher cavity takes an open-ended quarter-wavelength coaxial line cylindertype structure, the mechanical design of buncher cavity was done according to the physical design, adequate considerationought to be given to the factors of electromagnetic field distribution, power coupling, frequency tuning,cavity cooling and manufacturing, and so on.

关键词： Mechanical Design Fabrication

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

First-Principles Investigation of the Concentration Effect on Equilibrium Fractionation of K Isotopes in Feldspars

First-Principles Investigation of the Concentration Effect o...

引用

中国矿物岩石地球化学学会第17届学术年会

作者：李永辉 Wenzhong Wang shichun huang Kun Wang 吴忠庆 Laboratory of Seismology and Physics of Earth's Interior School of Earth and Space SciencesUniversity of Science and Technology of China Department of Earth and Planetary Sciences Washington University in St.Louis

The K concentration effects on K-O bond length and the reduced partition function ratios of K/K in alkali feldspars have been explored using the density function theory (DFT) method. In alkali feldspars,the average K-...

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

高温Ca同位素地球化学研究进展与双稀释剂校正

引用

地学前缘 2017年第5期24卷 402-415页

作者：张洪铭黄士春李曙光西北大学地质学系陕西西安710069 中国地质大学(北京)地球科学与资源学院北京100083 哈佛大学地球与行星科学系美国马萨诸塞州剑桥02138 内华达大学地球科学系美国内华达州拉斯维加斯89154 中国科学院壳幔物质与环境重点实验室中国科学技术大学地球和空间科学学院安徽合肥230026

近年来随着质谱和分析技术的进步,Ca同位素的分析精度获得了很大的提高,出现了很多高温条件下Ca同位素地球化学的研究成果。双稀释剂的合理使用在Ca同位素的分析中起关键作用。本文系统地阐述了前人对Ca同位素测试时所使用的双稀释剂技... 详细信息

近年来随着质谱和分析技术的进步,Ca同位素的分析精度获得了很大的提高,出现了很多高温条件下Ca同位素地球化学的研究成果。双稀释剂的合理使用在Ca同位素的分析中起关键作用。本文系统地阐述了前人对Ca同位素测试时所使用的双稀释剂技术,提供相应的计算程序,并且系统地归纳近年来高温条件下Ca同位素地球化学研究的新成果,包括单矿物对之间Ca同位素的分馏、陨石和地幔Ca同位素组成的不均一性和陨石的εCa异常及K-Ca定年等。斜方辉石和橄榄石相比于共生的单斜辉石更富集重Ca同位素,并且Δ44/40 CaOpx-Cpx受斜方辉石Ca含量和Ca—O键长的影响。地幔矿物之间具有不相同的Ca同位素组成说明地幔Ca同位素组成的不均一性。陨石及其内部难熔包裹体的Ca同位素组成变化范围很大,并且普遍存在εCa的异常。顽火辉石球粒陨石与地球具有相近的Ca同位素组成,表明它们可能具有相同的起源。但是高温条件下Ca同位素的分馏研究仍处于起步阶段,未来对于地球主要储库的Ca同位素组成、岩浆过程(部分熔融和分离结晶)和洋壳俯冲过程的Ca同位素分馏仍然需要更多地研究。

关键词： Ca同位素双稀释剂同位素分馏 εCa异常

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

激发圆形管道内多阶声模态的扬声器阵列控制方法

引用

声学学报 2022年第4期47卷 521-530页

作者：黄时春英基勇高翔蒋伟康上海交通大学机械系统与振动国家重点实验室上海200240 中国航发商用航空发动机有限责任公司上海200241 中国飞机强度研究所航空声学与振动航空科技重点实验室西安710065

声模态发生器是通过控制扬声器阵列在管道内激发声模态波的一种装置。为了解决在管道内同时激发多个声模态的问题,研究了激发圆形管道内多阶声模态的扬声器阵列控制方法。采用轴向多圈布置的声源阵列,并调节各个声源的幅值和相位,实现... 详细信息

声模态发生器是通过控制扬声器阵列在管道内激发声模态波的一种装置。为了解决在管道内同时激发多个声模态的问题,研究了激发圆形管道内多阶声模态的扬声器阵列控制方法。采用轴向多圈布置的声源阵列,并调节各个声源的幅值和相位,实现同时激发包括径向声模态在内的多个声模态。同时考虑声源的周向位置和轴向位置信息,建立各个声源与多个目标模态系数之间的线性关系,运用最小二乘法求解得到激发目标多模态所需各个声源的复强度(包括幅值和相位),所研制的高阶模态发生器以计算的声源复强度为输入量,采用数字信号系统控制扬声器输出的幅值和相位,用于实现管道内声源激发,该模态激发过程无需针对特定模态优化声源的位置。实验结果表明,所研制的模态发生器可精确激发单个或多个声模态,且目标模态系数信噪比几乎都大于10 dB。

关键词：扬声器阵列声模态激发过程最小二乘法轴向位置圆形管道高阶模态多模态

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

Low-Temperature Baking Effect of the Radio-Frequency Nb_(3)Sn Thin Film Superconducting Cavity

引用

Chinese Physics Letters 2021年第9期38卷 43-47页

作者： Ziqin Yang shichun huang Yuan He Xiangyang Lu Hao Guo Chunlong Li Xiaofei Niu Pingran Xiong Yukun Song Andong Wu Bin Xie Zhiming You Qingwei Chu Teng Tan Feng Pan Ming Lu Didi Luo Junhui Zhang Shenghu Zhang Wenlong Zhan Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China State Key Laboratory of Nuclear Physics and Technology Peking UniversityBeijing 100871China University of Chinese Academy of Sciences Beijing 100049China

The Nb_(3)Sn thin film cavity,having the potential to be operated at a higher temperature and higher gradient compared to the cavity made from bulk niobium,is one of the most promising key technologies for the nextgeneration radio-frequency superconducting *** our work,several 1.3 GHz single-cell TESLA-shaped Nb_(3)Sn thin film cavities,coated by the vapor diffusion method,were tested at Peking University and Institute of Modern Physics,Chinese Academy of *** was observed that the performance of the Nb_(3)Sn thin film cavities in the tests without the slow cooling down procedure and the effective magnetic field shielding was significantly improved by using a low temperature baking at 100℃for 48 *** the peak electric field of the cavity remained unchanged,the rapid drop of the unloaded Q value(Q0)with the increasing accelerating field(Q-slope)was effectively eliminated,resulting in an improvement of the Q0 in the intermediate field region by~8 ***,under better test conditions with the shielded magnetic field less than 5 mG and the slow cooling down procedure in the temperature range of 25-15 K,the Q0 was still improved by about 20%.Our study shows that the low temperature baking can be an effective supplement to the effective post-treatment for the Nb_(3)Sn thin film cavity.

关键词： cavity film unchanged

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：