检索结果-南通市图书馆

Observation of pentaquark states and prospectives of further studies

在线全文

学校读者我要写书评

暂无评论

Science Bulletin 2015年第17期60卷 1549-1550页

作者： cheng-Ping Shen Chang-Zheng yuan School of Physics and Nuclear Energy Engineering Beihang University Institute of High Energy Physics Chinese Academy of Sciences

The quark model based on quark–antiquark mesons and three-quark baryons has been very successful in classifying the ***,quantum chromodynamics(QCD)does not forbid the existence of exotic hadronic states with other qu... 详细信息

关键词：五夸克态夸克胶子结构量子色动力学强子态夸克模型反夸克 QCD 杂交种

Mei Symmetry and Lutzky Conserved Quantity for Nonholonomic Mechanical System with Unilateral Constraints

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2008年第3期49卷 575-578页

作者： JING Hong-Xing LI yuan-cheng College of Physics Science and Technology China University of Petroleum （East China） Dongying 257061 China

In this paper, we study the Mei symmetry which can result in a Lutzky conserved quantity for nonholonomic mechanical system with unilateral constraints. The definition and the criterion of the Mei symmetry for the system are given. The necessary and sufficient condition under which the Mei symmetry is a Lie symmetry for the system is obtained. A Lutzky conserved quantity deduced from the Mei symmetry is gotten. An example is given to illustrate the application of our results.

关键词： nonholonomic mechanical system unilateral constraint Mei symmetry Lutzky conserved quantity

Towards relieving center segregation in twin-roll cast Al-Mg-Si-Cu strips by controlling the thermal-mechanical process

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2023年第17期148卷 31-40页

作者： Shao-You Zhang Xuan Wang yuan-Ting Mo cheng Wang Tuo cheng Orest Ivasishin Pin-Kui Ma Hui-yuan Wang Key Laboratory of Automobile Materials of Ministry of Education&School of Materials Science and Engineering Nanling CampusJilin UniversityChangchun 130025China International Center of Future Science Jilin UniversityChangchun 130012China

Serious center segregation greatly limits the application of twin-roll casting(TRC)technology for produc-ing 6xxx alloy ***,Al-0.9Mg-0.6Si-0.2Cu-0.1Fe(wt.%,6061)strips with different thicknesses were fabricated by TRC,and we found that the center segregation was well relieved with the thick-ness increased from 3 mm to 4 *** reveal the mechanisms of mitigation of center segregation in the 4 mm strip,various techniques including solidification simulation,crystallographic calculation,elec-tron backscatter diffraction(EBSD),and electron probe micro-analyzer(EPMA)were *** re-sults disclosed that the Fe-containing phase in the 3 mm strip wasπ-AlFeMgSi,while the counterpart in the 4 mm strip wasα-***α-AlFeSi could serve as nucleation substrates for Mg_(2)Si and Q-AlCuMgSi phases,thus promoting the uniform distribution of elements and preventing the accumulation of phases in the center *** matching planes between theα-AlFeSi and Q/Mg_(2)Si were exam-ined as:(1120)_(α-AlFeSi)//(0001)_(Q),(0001)_(α-AlFeSi)//(110)_(Mg2Si),and(1120)_(α-AlFeSi)//(110)_(Mg2Si).Meanwhile,the smaller roll separating force during the TRC process in the 4 mm strip could weaken the force-induced liquid flow behavior in the semi-solid region,which is the other reason for the alleviation of center *** to the elimination of the center segregation,a more excellent fracture elongation was achieved in the as-homogenized 4 mm strip(∼29%)compared with the counterpart of the 3 mm strip(∼20%).This work may provide a strategy to eliminate the center segregation,thus further promoting the application of TRC process and producing high-performance Al alloy strips efficiently.

关键词： Aluminum alloy Twin-roll casting Center segregation Fe-containing phase Nucleation substrate

Extraction of Tungsten and Molybdenum by Various Organic Compounds as Extractants

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

Rare Metals 1989年第3期9卷 15-19页

作者： yuan, Qun cheng, Xin Luo, Jiazhen yuan, chengye Shanghai Inst of Organic Chemistry China

Seventy organic compounds including various organophosphorus esters, amines and oxygen-based ligands were investigated as extractants. The experiment results show that amines are excellent extractants for W and Mo. Their sequence of extraction ability for W is as follows: quarternary amine > tertiary amine > secondary amine > primary amine. Acidic organophosphorus extractants do not extract W, but can extract Mo with high extraction ability from the acidic solution. These extractants could provide a potential process for separating W from Mo.

关键词： Alcohols Applications Amines Applications Molybdenum Ore Treatment Solvent Extraction Phosphorus Compounds Organic Solvents Organic

Primary study on solvent effect of COCA4 by laser photolysis

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2007年第5期18卷 272-275页

作者： cheng Kemei YAO Side yuan Lihua Institute of Chemical Materials China Academy of Engineering Physics Mianyang 621900 China Institute of Applied Physics Chinese Academy of Sciences Shanghai 210008 China College of Chemistry Sichuan University Chengdu 610064 China

Reaction of p-tert-oxocalix[4]arene in acetonitrile (CH3CN) by 308nm laser pulses was investigated to understand its mechanism as polymer stabilizer. Four main absorption bands were observed at 300nm, 400nm, 460nm and 540nm. The 300nm absorption was assigned to the absorption of phenoxy radical, and the 460nm and 540nm were triple state absorption. It was concluded that the relative stable phenoxy radical mediate was formed through intramolecular energy transition of carbonyl triplet after laser excitation in CH3CN. The formation mechanism of phenoxyl radical was quite different from that in cyclohexane (C6H12), which was cooperation of two-photon process and one-photon process.

关键词：芳香烃光分解激光化学液体系统

Design of nanozymes for inflammatory bowel disease therapy

在线全文

学校读者我要写书评

暂无评论

Science China(Life Sciences) 2021年第8期64卷 1368-1371页

作者： Chaoqun cheng Sheng Zhao yuan cheng Yufeng Liu Hui Wei Department of Biomedical Engineering College of Engineering and Applied SciencesNanjing National Laboratory of MicrostructuresJiangsu Key Laboratory of Artificial Functional MaterialsNanjing UniversityNanjing 210023China State Key Laboratory of Analytical Chemistry for Life Science School of Chemistry and Chemical EngineeringChemistry and Biomedicine Innovation Center(ChemBIC)Nanjing UniversityNanjing 210023China

Nanozymes,the functional nanomaterials with enzyme-like activities,have been widely explored for both in vitro and in vivo applications(Wei and Wang,2013;Wu et al.,2019;Huang et al.,2019;Liang and Yan,2019).Particularly,by modulating the levels of reactive oxygen species(ROS)in vivo,numerous therapeutic nanozymes have been developed to treat diseases,ranging from cancer to neurodegenerative diseases(Fan et al.,2018;Kwon et al.,2018).

关键词： diseases vivo

Enhancements of Passive Film and Pitting Resistance in Chloride Solution for 316LX Austenitic Stainless Steel After Sn Alloying

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2019年第1期32卷 98-106页

作者： yuan-yuan Yang yuan-yuan Liu Man-Lang cheng Nian-Wei Dai Min Sun Jin Li Yi-Ming Jiang Department of Materials Science Fudan University

In the present work, the electrochemical behavior and properties of the passive film of a new Sn-alloyed 316 LX austenitic stainless steel were investigated. With the increase in Sn content in 316 LX austenitic stainless steel from 0 to 0.21%, the critical pitting temperature value increased from 32.6 to 38.8 °C, and the pitting potential increased from 0.252 V_(SCE) to 0.317 V_(SCE). Electrochemical impedance spectroscopy results showed that the corrosion resistance of passive film rose with the increase in Sn content, indicating a more stable passive film. The Mott–Schottky measurement revealed an n-type passive film with a decreased carrier concentration on the 316 LX austenitic stainless steel surface. The Cr, Sn^(2+) and Sn^(4+)(SnO, SnOHCl or SnO_2) enrichments were observed in the passive layer by X-ray photoelectron spectroscopy. The enrichment of Sn and Cr in the passive film can account for the enhanced pitting resistance of 316 LX austenitic stainless steel in chloride solution.

关键词： Austenitic stainless steel Sn alloying Pitting Chloride solution

Lie Symmetry and Generalized Mei Conserved Quantity for Nonconservative Dynamical System

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2008年第5期49卷 1148-1150页

作者： JING Hong-Xing LI yuan-cheng College of Physical Science and Technology China University of Petroleum （East China） Dongying 257061 China

Based on the total time derivative along the trajectory of the system, for noneonservative dynamical system, the generalized Mei conserved quantity indirectly deduced from the Lie symmetry of the system is studied. Firstly, the Lie symmetry of the system is given. Then, the necessary and sumeient condition under which the Lie symmetry is a Mei symmetry is presented and the generalized Mei conserved quantity indirectly deduced from the Lie symmetry of the system is obtained. Lastly, an example is given to illustrate the application of the result.

关键词： Lie symmetry Mei symmetry generalized Mei conserved quantity nonconservative dynamicalsystem

High-temperature corrosion of Sn-Bi-Zn-Ga alloys as heat transfer fluid

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2021年第8期40卷 2221-2229页

作者： Qing-Meng Wang Xiao-Min cheng yuan-yuan Li Guo-Ming Yu Zhi Liu School of Materials Science and Engineering Wuhan University of TechnologyWuhan430070China School of Mechanical and Electrical Engineering Huanggang Normal UniversityHuanggang438000China

The new heat transfer alloy is highly reactive at high temperatures,and the corrosion of the container material determines the service life of the heat transfer *** high-temperature corrosion of Sn-Bi-Zn-Ga alloys as heat transfer fluid was *** microstructure and elemental distribution were studied by field emission scanning electron microscopy(FESEM)and energy dispersive spectroscopy(EDS).The thermal properties before and after corrosion were studied by differential scanning calorimetry(DSC).The results show that the corrosion kinetics of the studied materials follows the parabolic law and the thermal properties after corrosion are *** significantly improves the thermal conductivity.316 stainless steel exhibits excellent corrosion resistance due to its high Cr and Ni *** mechanism analysis shows that the oxidation of Ga has a smaller Gibbs free energy,and an oxide forms at the corrosion interface to prevent dissolution corrosion and oxidative corrosion of the container material.

关键词： Sn-Bi-Zn-Ga Heat transfer fluids Thermophysical properties High-temperature corrosion