检索结果-南通市图书馆

Gravitational Corrections to Energy-Levels of a Hydrogen Atom

在线全文

学校读者我要写书评

暂无评论

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

Antikaon Condensation and In-medium Kaon and Antikaon Production in Protoneutron Stars

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2007年第1期47卷 111-118页

作者： GU Jian-Fa guo Hua li xi-guo liU Yu-xin XU Fu-Rong Department of Technical Physics and MOE Laboratory of Heavy Ion Physics Peking University Beijing 100871 China Center of Theoretical Nuclear Physics National Laboratory of Heavy Ion Accelerator Lanzhou 730000 China Institute of Modern Physics The Chinese Academy of Sciences Lanzhou 730000 China Department of Physics Peking University Beijing 100871 China

Antikaon condensation and kaon and antikaon production in protoneutron stars are investigated in a chiral hadronic model （also referred to as the FST model in this paper）. The effects of neutrino trapping on protoneutron stars are analyzed systematically. It is shown that neutrino trapping makes the critical density of K^- condensation delay to higher density and fifo condensation not occur. The equation of state （EOS） of （proto）neutron star matter with neutrino trapping is stiffer than that without neutrino trapping. As a result, the maximum masses of （proto）neutron stars with neutrino trapping are larger than those without neutrino trapping. If hyperons are taken into account, antikaon does not form a condensate in （proto）neutron stars. Meanwhile, the corresponding EOS becomes much softer, and the maximum masses of （proto）neutron stars are smaller than those without hyprons. Finally, our results illustrate that the Q values for K^＋ and K^- production in （proto）neutron stars are not sensitive to neutrino trapping and inclusion of hyperons.

关键词： protoneutron stars antikaon condensation neutrino trapping

In-situ observation of microstructural evolution in reheated low carbon bainite weld metals with various Ni contents

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2017年第12期24卷 1206-1214页

作者： Gao-jun Mao Rui Cao Jian-hong Chen xi-li guo Yong Jiang Department of Materials Science and Engineering Lanzhou University of TechnologyLanzhou 730050GansuChina State Key Laboratory of Advanced Processing and Recycling of Non ferrous Metals Lanzhou University of TechnologyLanzbou 730050GansuChina Atlantic China Welding Concumables Inc.Zigong 643000SichuanChina

Microstructural evolution in weld metals was in-situ observed through utilizing a laser scanning confocal microscope at two cooling *** specimens with various nickel contents were adopted for the *** the specimen with low fraction of Ni（≤2 wt.%）,granular bainite microstructure（*** surface relief）transformation from intragranular nucleation site was in-situ observed,while,lath bainite microstructure originating from grain boundary of austenite was in-situ observed for specimens with high mass percentage of Ni（≥4 wt.%）.With increasing nickel content,the transformation temperature *** prior austenite grain size was initially depressed and subsequently coarsened dramatically with the addition of *** microstructure difference was ascribed to various nucleation sites and growth direction in the *** account of those observations,not only the chemical component,cooling rate and microstructure were systematically correlated,but also the microstructural evolution was definite.

关键词： Weld metal Ni content Bainite Nucleation site Growth In-situ observation

Combining TOPSIS and GRA for supplier selection problem with interval numbers

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2018年第5期25卷 1116-1128页

作者：张萌李国喜 College of Mechatronic Engineering and Automation National University of Defense Technology

Supplier selection can be regarded as a typical multiple attribute decision-making problem. In real-world situation, the values of the alternative attributes and their weights are always being nondeterministic, and as a result of this, the values are considered interval numbers. In addition, the common approach to measure the similarity between alternatives through their distance suffers from some minor shortcomings. To address these problems, this study develops a novel hybrid decision-making method by combining the technique for order preference by similarity to an ideal solution （TOPSIS） with grey relational analysis （GRA） for supplier selection with interval numbers. By introducing the intervals theory, the extensions of Euclidean distance and grey relational grade are defined. And then a new comprehensive closeness coefficient is constituted for supplier alternatives evaluation based on the interval Euclidean distance and the interval grey relational grade, which could indicate the distance-based similarity and the shape-based similarity simultaneously. A mtmerical example is taken to validate the flexibility of the proposed method, and result shows that this method can tackle the uncertainty in real-world supplier selection and also help decision makers to effectively select optimal suppliers.

关键词： supplier selection interval number grey relational analysis (GRA) technique for order preference by similarity to an ideal solution (TOPSIS)

Gasser-Leutwyler Coefficients of Chiral Lagrangian for Pseudoscalar Goldstone Bosons

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2006年第1X期46卷 101-108页

作者： ZHOU li-Juan WU Qing PAN Ji-Huan MENG Cheng-Ju MA Wei-xing li xi-guo Collaboration Group of Hadron Physics and Non-perturbative QCD Study Guangxi University of Technology Liuzhou 545006 China Department of Physics Qingdao University Qingdao 266071 China Department of Physics Hechi College Yizhou 546300 China Institute of High Energy Physics the Chinese Academy of Sciences Beijing 100049 China Institute of Modern Physics the Chinese Academy of Sciences Lanzhou 730000 China

Based on the Dyson-Schwinger equations in raAnbow approximation for quark propagator with an effective gluon propagator, and on the parametrized fully dressed quark propagator proposed by us, the unknown GasserLeutwyler coeiticients of the chiral Lagrangian for pseudoscalar Goldstone bosons, li, are predicted respectively. The predicted values of li in the two different ways are not only in reasonable agreement each other but also in agreement with empirical values used widely in literature and the values predicted by many other theoretical models with QCD characteristics. The compatible results of Gasser-Leutwyler coefficients predicted by our parameterized quark propagator, in turn, clearly verify its extensive validity.

关键词： chiral perturbation theory Gasser-Leutwyler coefficient quark propagator Dyson-Schwinger equations

Distribution of oxide inclusions in H13 castings under super-gravity field with multi-stage rotation speeds

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2024年第1期31卷 121-133页

作者： Shao-ying li xiao-jun xi xing-ming Zhao Han-jie guo Jing guo School of Metallurgical and Ecological Engineering University of Science and Technology Beijing(USTB)Beijing100083China Beijing Key Laboratory of Special Melting and Preparation of High-End Metal Materials Beijing100083China Beijing Beiye Functional Materials Corporation Beijing100192China Shandong Tianwu Forming Technology Co. Ltd.Liaocheng252024ShandongChina

The 42 kg industrial H13 castings were prepared by different super-gravity fields with multi-rotation speeds,and the distribution of oxide inclusions in the castings was *** addition,the inward movement Reynolds number and inward movement time of oxide inclusions as well as the solidification time of molten steel at different positions in the castings were calculated to clarify the removal mechanism of oxide inclusions in super-gravity *** results show that the large size(i.e.,greater than 10μm)oxide inclusions are mainly concentrated in the inner and outer parts of the super-gravity castings with constant rotation speed(500 r min^(-1))and five-stage rotation speeds(500,600,750,850,and 950 r min^(-1)),respectively,while there are no large oxide inclusions in the super-gravity castings with three-stage rotation speeds(500,600,and 750 r min^(-1)).Although an increase in the particle size of inclusion and the rotation speed in super-gravity field is conducive to the increase in the inward movement Reynolds number of oxide inclusions and reduction in the inward movement time of oxide inclusions,it will reduce the local solidification time of molten *** the range of the rotation speed studied,the super-gravity field with three-stage rotation speeds has the best effect on the removal of inclusions in H13 molten steel.

关键词： Distribution Oxide inclusion H13 casting Super-gravity field Rotation speed

Effect of Toxins Isolated from Exserohilum monoceras (Drechsler) Leonard and Suggs on Echinochloa crus-galli (L.) Beauv.

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

Agricultural Sciences in China 2009年第8期8卷 972-978页

作者： CHEN Yong ZHENG Wei WANG li-ming CUI Hai-lan li guo-xi liUxin-gui HAN Cheng-chou ZENG Ren-sen Weed Science Laboratory College of Agriculture South China Agricultural University Guangzhou 510642 P.R.China Department of Weed and Rodent Biology and Management Institute of Plant Protection Chinese Academy of Agricultural SeieneesBeijing 100193 P.R.China

Exserohilum monoceras （Drechsler） Leonard and Suggs is a potential biocontrol agent for the control of Echinochloa species. This fungus causes leaf blight in Echinochloa species, but does not damage rice. Phytotoxicity of the fungal fermented broth was evaluated through the bioassay and the active ingredients were preliminarily isolated by using silica gel column chromatography （CC） in this study. The most active fraction 5-Ⅲ was obtained and analyzed by gas chromatography-mass spectrometry （GC-MS）. The results show that 5-Ⅲ consisted of many compounds, in which 36 compounds accounted for 94.24% of total peak area. Di-n-butyl phthalate （DBP） displayed the highest activity accounted for 9.24% of the total peak area, suggesting that DBP may be one of the main active compounds produced by E. monoceras.

关键词： Exserohilum monoceras phytotoxin active ingredients Echinochloa crus-galli

Sedimentary Environment and Mineralization of the Black Shale Polymetallic Layer in the Early Cambrian,SW China:Constraints from in situ LA-ICP-MS Analysis of Pyrite

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2024年第2期98卷 416-429页

作者： YANG Zhen FU Yong li Chao CAI xi guo Chuan College of Eco-Environmental Engineering Guizhou Minzu UniversityGuiyang 550025China College of Resources and Environmental Engineering Guizhou UniversityGuiyang 550025China Key Laboratory of Karst Georesources and the Environment Ministry of EducationGuizhou UniversityGuiyang 500025China National Research Center for Geoanalysis Chinese Academy of Geological SciencesBeijing 100037China

A polymetallic layer is usually developed at the bottom of the early Cambrian black shale in Guizhou *** mineral that makes up the polymetallic layer is related to the sedimentary *** analyze the differentiation mechanism between polymetallic deposits(Ni-Mo and V),the Zhijin Gezhongwu profile located in the outer shelf and the Sansui Haishan V deposit located in the lower slope are selected to study the in situ sulfur isotopes and trace elements of *** results show that δ^(34)S values of pyrite vary widely from−7.8‰to 28‰in the Gezhongwu profile,while the δ^(34)S values are relatively uniform(from 27.8‰to 38.4‰)in the Haishan *** isotopic S composition is consistent with the transition that occurs in the sedimentary phase from the shelf to the deep sea on the transgressive Yangtze platform;this indicates that the δ^(34)SO_(4)^(2−)values in seawater must be differently distributed in depositional *** sulfur in the Ni-Mo layer is produced after the mixing of seawater and hydrothermal fluid,while the V layer mainly originates from ***,the Ni-Mo and V deposits have been differentiated primarily on the basis of the combined effect of continental weathering and hydrothermal fluid.

关键词： sedimentary environment black shale polymetallic layer pyrite early Cambrian

Phosphotungstic acid immobilized on amino-functionalized TS-1 zeolite as a solid acid catalyst for the synthesis of tributyl citrate

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2024年第6期70卷 199-210页

作者： Pei li Bianfang Shi Junyao Shen Ran Cui Wenze guo ling Zhao Zhenhao xi State Key Laboratory of Chemical Engineering East China University of Science and TechnologyShanghai 200237China Key Laboratory of Smart Manufacturing in Energy Chemical Process Ministry of EducationEast China University of Science and TechnologyShanghai 200237China

The amino-functionalization of TS-1 zeolite followed by immobilization of phosphotungstic acid(HPW)was presented to prepare a strong solid acid catalyst for the synthesis of bio-based tributyl citrate from the esterification of citric acid and n-butanol.γ-Aminopropyltriethoxysilane(APTES)was first grafted on the TS-1 zeolite via the condensation reactions with surface hydroxyl groups,and subsequently the HPW was immobilized via the reaction between the amino groups and the protons from HPW-forming strong ionic *** Keggin structure of HPW and MFI topology of TS-1 zeolite were well maintained after the *** amino-functionalization generated abundant uniformly distributed active sites on TS-1 for HPW immobilization,which promoted the dispersity,abundance,as well as the stability of the acid *** tetrahedrally coordinated framework titanium and non-framework titania behaved as weak Lewis acid sites,and the protons from the immobilized HPW acted as the moderate or strong Brønsted acid *** optimized TBC yield of 96.2%(mol)with a conversion of-COOH of 98.1%(mol)was achieved at 150℃for 6 h over the HPW immobilized on amino-functionalized *** catalyst exhibited good stability after four consecutive reaction runs,where the activity leveled off at still a relatively high level after somewhat deactivation possibly caused by the leaching of a small portion of weakly anchored APTES or HPW.

关键词： Amino-functionalization Phosphotungstic acid TS-1 zeolite Esterification Tributyl citrate