检索结果-南通市图书馆

Effect of temperature and stress on molecular structure and carbon monoxide generation of lignite from Kailuan mining area

引用

International Journal of Mining Science and Technology 2016年第3期26卷 437-441页

作者： xiao Cangyan Wei Chongtao guo Li Wen Shen Jian Key Laboratory of Coalbed Methane Resources & Reservoir Formation Processes Ministry of Education School of Resources and Earth Science China University of Mining and Technology North China Institute of Aerospace Engineering

In order to analyze the origin of carbon monoxide(CO) in coal seams, stress–strain experiments under temperature of 50, 150 and 250 °C were conducted using lignite from Kailuan mining area. Fourier transform infrared spectroscopy and elemental analysis were carried out before and after deformation of the samples. The results indicated that CO generated at 150 and 250 °C; the gas component was mostly oxygen(O_2), with small amount of carbon dioxide(CO_2), methane(CH_4) and hydrogen(H_2). At 50 °C, O_2 and a little CO_2 were observed and no CO was found. The carbon content of the coal samples increased slightly after deformation, and the oxygen content, H/C ratio, and O/C ratio decreased. The molecular structure of coal displayed different evolution characteristics at various temperatures. At 50 and 150 °C, the falling off of side chains, broken of ether bond and directional realignment of the aliphatic chains resulting in the formation of long chains were the main performance of coal molecular structure evolution. While at 250 °C, the side chains fell off and short chains formed. Furthermore, at both 150 and 250 °C, condensed degree of aromatic ring increased. Under the action of temperature and pressure, CO forms in two *** first is that ether bond breaks, oxygen and carbon atoms combine together and forms CO, or O_2 forming in the broken of ether–oxygen bond leads to the oxidation of free radicals and resulting in the formation of CO. And the second is that CO derives from falling off of C=O group.

关键词： Lignite Molecular structure Carbon monoxide generation Deformation Temperature

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

普洱茶多糖结构及抗氧化活性的比较研究

引用

粮食与油脂 2024年第8期37卷 117-121页

作者：沈晓静袁彪郭毅冯宇王捷姜薇薇云南农业大学理学院云南昆明650201 云南省药用植物生物学重点实验室云南昆明650201 云南特色植物提取实验室云南昆明650106

以普洱熟茶和生茶为原料,采用超声提取熟茶粗多糖(ICP)和生茶粗多糖(ACP)并对其进行分离纯化制备熟茶精多糖(IPP)和生茶精多糖(APP)。同时,结合傅里叶变换红外光谱(FT-IR)和扫描电子显微镜(SEM)对多糖结构特征进行表征;通过体外抗氧化... 详细信息

以普洱熟茶和生茶为原料,采用超声提取熟茶粗多糖(ICP)和生茶粗多糖(ACP)并对其进行分离纯化制备熟茶精多糖(IPP)和生茶精多糖(APP)。同时,结合傅里叶变换红外光谱(FT-IR)和扫描电子显微镜(SEM)对多糖结构特征进行表征;通过体外抗氧化试验评估普洱茶多糖的抗氧化能力。结果表明:熟茶多糖具有紧致、密集的球状嵌合体结构,生茶多糖则呈松散的海绵状多孔结构,且APP孔状结构清晰规整。普洱茶多糖具有一定的抗氧化活性,以ICP的抗氧化活性最强。

关键词：普洱茶多糖纯化结构抗氧化活性

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

Micromagnetism simulation on effects of soft phase size on Nd2Fe14B/α-Fe nanocomposite magnet with soft phase imbedded in hard phase

引用

Chinese Physics B 2018年第8期27卷 529-534页

作者： Yu-qing Li Ming Yue Yi Pen Hong-guo Zhang College of Materials Science and Engineering Beijing University of TechnologyBeijing 100124China

In this study, micromagnetism simulation by using timte dltterence method is cameo out on the Ncl21-el415/a-Fe nanocomposite magnet with soft phase imbedded in hard phase. The effects of soft magnetic phase size （S） on the magnetic properties and magnetic reversal modes are systematically analyzed. As S increases from 1 nm to 48 nm, the remanence （Jr） increases, while the coercivity （Hci） decreases, leading to the result that the magnetic energy prod- uct [（BH）max] first increases slowly, and then decreases rapidly, peaking at S = 24 nm with the （BH）max of 72.9 MGOe （1 MGOe = 7.95775 kJ.m-3）. Besides, with the increase of S, the coercivity mechanism of the nanocomposite magnet changes from nucleation to pinning. Furthermore, by observing the magnetic moment evolution in demagnetization pro- cess, the magnetic reversal of the soft phase in the nanocomposite magnet can be divided into three modes with the increase of S： coherent rotation （S 〈 3 nm）, quasi-coherent rotation （3 nm≤S 〈 36 nm）, and the vortex-like rotation （S ≥36 nm）.

关键词： micromagnetism simulation magnetization dynamics, Nd2Fe14B/a-Fe nanocomposite magnets

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

Response of ocean climate to different heat-flux perturbations over the North Atlantic in FAFMIP

引用

气候变化研究进展:英文版 2023年第4期14卷 546-559页

作者： Wen-Yu YIN Xin GAO Run guo Peng FAN Guang-qing ZHOU International Center for Climate and Environment Sciences Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China

The diversity of surface-flux perturbations,especially for heat-flux perturbations,notably leads to uncertainties surrounding the responses of ocean climate under global warming scenarios projected by climate/Earth system ***,when imposing heat-flux perturbations on the models,strong feedback persists between the atmosphere and the ocean,resulting in nearly doubled heat-flux perturbation over the North Atlantic(NA).Herein,quantitative evaluation of the influences of magnitude change of heat-flux perturbations over the NA on the changes in the Atlantic Meridional Overturning Circulation(AMOC),ocean heat uptake(OHU)and dynamic sea level(DSL)has been conducted by analysis of eight coupled model responses to the heat-flux perturbation experiments in the Flux-Anomaly-Forced Model Inter-comparison *** has been demonstrated that the magnitude of the AMOC change is extremely sensitive to the magnitude change of imposed NA heat-flux perturbation,and the weakening amplitude of the AMOC is nearly halved as the imposed heat-flux perturbation F is halved over the *** most remarkable responses of both DSL and OHU to the magnitude changes of NA heat-flux perturbation have been primarily found in the Atlantic and Arctic basins,especially for the NA *** the added ocean heat uptake(OHUa)and redistributed ocean heat uptake(OHUr)play key roles in OHU changes among the various NA heat-flux perturbation *** magnitude change of NA-mean OHUa is almost linearly related to the imposed NA heat-flux perturbation,while the magnitude change of NA-mean OHUr,which is primarily caused by AMOC change and redistributed heat flux,is not proportional to the imposed NA heat-flux *** is a nearly linear relationship between the magnitude of AMOC change and the OHUr in tropical regions,including the regions in the low-latitude South Atlantic,the tropical Pacific Ocean and the Indian Ocean.

关键词： Heat-flux perturbation Ocean heat uptake North Atlantic Atlantic meridional overturning circulation Coupled general circulation model

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

Gravitational Corrections to Energy-Levels of a Hydrogen Atom

引用

Communications in Theoretical Physics 2007年第4期47卷 658-662页

作者： ZHAO Zhen-Hua LIU Yu-xiao LI Xi-guo Institute of Modern Physics the Chinese Academy of Sciences Lanzhou 730000 China Institute of Theoretical Physics Lanzhou University Lanzhou 730000 China

The first-order perturbations of the energy levels of a hydrogen atom in central internal gravitational field are investigated. The internal gravitational field is produced by the mass of the atomic nucleus. The energy shifts are calculated for the relativistic 1S, 2S, 2P, 3S, 3P, 3D, 4S, and 4P levels with Schwarzschild metric. The calculated results show that the gravitational corrections are sensitive to the total angular momentum quantum number.

关键词： hydrogen atom gravitational perturbation generally covariant Dirac equation

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 Novel Palladium-Catalyzed Reaction and Its Application in Preparation of Derivatives of Stilbazols

引用

Chinese Chemical Letters 2001年第5期12卷 399-402页

作者： Zhi Yong WANG Chao JIANG Ji Hui WU qing Xiang guo Dept.of Chem. University of Science&Technology of ChinaHefei 230026

A novel palladium-catalyzed coupling reaction for the preparation of derivatives of stilbazoles was presented. A series of stilbazoles were synthesized firstly by this highly efficient method. From this reaction it wa... 详细信息

关键词： Palladium catalyzed preparation stilbazole

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

P-V Criticality of an AdS Black Hole in f(R)Gravity

引用

Chinese Physics Letters 2013年第6期30卷 38-41页

作者： CHEN Song-Bai LIU xiao-Fang LIU Chang-qing Institute of Physics and Department of Physics Hunan Normal UniversityChangsha 410081 Key Laboratory of Low Dimensional Quantum Structures and Quantum Control Ministry of EducationHunan Normal UniversityChangsha 410081

We study the thermodynamics of a charged AdS black hole in the special f(R)correction with the constant Ricci scalar *** results show that the f(R)correction influences the Gibbs free energy and the phase transition of *** ratioρc occurring at the critical point increases monotonically with the derivative term f'(R0).We also disclose that the critical exponents are the same as those of the liquid-gas phase transition in the van der Waals model,which does not depend on the f(R)correction considered here.

关键词： correction (R) critical

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

Influences of fluorine auxochrome in fluorene molecular electroluminescent material on optoelectronic property

引用

Chinese Science Bulletin 2008年第19期53卷 2940-2945页

作者： LOU ShuangLing YU dunSheng JIANG YaDong guo guoJun ZHANG qing State Key Laboratory of Electronic Thin Films and Integrated Devices School of Optoelectronic Information University of Elec-tronic Science and Technology of China (UESTC) Chengdu 610054 China Department of Polymer Science School of Chemistry and Chemical Technology Shanghai Jiao Tong University Shanghai 200240China

The UV-Vis absorption and photoluminescence (PL) spectra of 2,3-bis(9,9-dihexyl-9H-fluoren-2-yl) quinoxaline (Py), 2,3-bis(9,9-dihexyl-9H-fluoren-2-yl)-6,7-difluoroquinoxaline (F2Py) and 2,3-bis(9,9- dihexyl-9H-fluoren-2-yl)-5,6,7,8-tetrafluoroquinoxaline (F4Py), which are fluorene molecular derivatives with conjugated structure, were investigated. For further investigation of the influences of fluorine auxochrome in fluorene molecular electroluminescent material on optoelectronic property, the elec- troluminescence (EL) characteristics of materials were studied by double-layer organic light-emitting diodes (OLEDs) using N,N'-Di-[(1-naphthalenyl)-N,N'-diphenyl]-(1,1'-biphenyl)-4,4'-diamine (NPB) as a hole transporting layer (HTL) with the conventional vacuum deposition method. The results showed that the absorption and PL spectra of materials in film state red shifted with fluorine substituents in- creased in molecule configuration. The performance of OLEDs is as follows: at a bias voltage of 5 V, Py emitted a blue-green light at 508 nm with the Commission Internationale d'Eclairage (CIE) coordinates of (0.23, 0.43) and full width at half maximum (FWHM) of 100 nm. The device had a turn-on voltage (de- fined as the drive voltage at the luminance of 1 cd/m2) of 4.8 V, a luminance of 129 cd/m2 with a current density of 59 mA/cm2 at 10 V, and a maximum luminous efficiency of 0.18 lm/W at 5.4 V. F2Py and F4Py emitted a green light peaking at 544 nm and a yellow light at 570 nm at 5 V, with the CIE coordinates of (0.38, 0.56) and (0.44, 0.49), and FWHM of 103 and 117 nm, respectively. The F2Py and F4Py devices had a turn-on voltage of 4 and 2 V, a luminance of 557 and 3300 cd/m2 with a current density of 100 and 880 mA/cm2 at 10 V, and a maximum luminous efficiency of 0.22 lm/W at 7.6 V and 0.53 lm/W at 2 V, respectively.

关键词：助色团芴分子电致发光光电子学

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

Synthesis and mesomorphic properties of novel tolane-type liquid crystals

引用

Chinese Chemical Letters 2009年第11期20卷 1283-1286页

作者： Dong Yu Zhao qing Yong Meng xiao Peng Cui Huai Yang Department of Materials Physics and Chemistry School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China

Two series of novel tolane-type liquid crystals （LCs） comprising of hydrogen-bonded organic acids were synthesized. The formation of dimerized H-bond LCs was confirmed by IR spectroscopy, and mesomorphic properties of the LCs were investigated by differential scanning calorimetry （DSC） and polarizing optical microscopy （POM）. It was found that the end groups of the liquid crystals as well as the unsaturated rigid core had effect on the mesomorphic properties.

关键词： Tolane Hydrogen-bonded liquid crystal Mesomorphic properties Synthesis

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

Forward a spatio-temporal trend surface for long-term groundmeasured albedo upscaling over heterogeneous land surface

引用

International Journal of Digital Earth 2018年第5期11卷 470-484页

作者： xiaodan Wu Jianguang Wen qing xiao Dongqin You Qiang Liu Xingwen Lin State Key Laboratory of Remote Sensing Science Institute of Remote Sensing and Digital EarthChinese Academy of SciencesBeijingPeople’s Republic of China College of Resources and Environment University of Chinese Academy of SciencesBeijingPeople’s Republic of China Joint Center for Global Change Studies BeijingPeople’s Republic of China College of Global Change and Earth System Science Beijing Normal UniversityBeijingPeople’s Republic of China

Upscaling ground albedo is challenged by the serious discrepancy between the heterogeneity of land surfaces and the small number of ground-based *** ground-based measurements cannot provide sufficient information on the characteristics of surface albedo at the scale of coarse pixels over heterogeneous land *** method of overcoming this problem is to introduce high-resolution albedo imagery as ancillary information for ***,due to the low frequency of updating of high-resolution albedo maps,upscaling time series of ground-based albedo measurements is *** paper proposes a method that is based on the idea of conceptual universal scaling methodology for establishing a spatiotemporal trend surface using very few high-resolution images and time series of ground-based measurements for spatial-temporal upscaling of *** construction of the spatiotemporal trend surface incorporates the spatial information provided by auxiliary remote sensing images and the temporal information provided by long time series of ground *** approach was illustrated by upscaling ground-based fine-scale albedo measurements to a coarse scale over the core study area in *** results indicate that this method can characterize the spatiotemporal variations in surface albedo well,and the overall correlation coefficient was 0.702 during the study period.

关键词： Trend surface upscaling spatiotemporal heterogeneous albedo

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

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：