检索结果-南通市图书馆

One-pot Two-Step Cycloaddition Reaction for Convenient Synthesis of Polycyclic Spirooxindole-fused [1,3]Oxazines

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2015年第9期33卷 1049-1056页

作者： Jing Sun Hui gong Chaoguo yan College of Chemistry & Chemical Engineering Yangzhou University Yangzhou Jiangsu 225002 China

The novel spirooxindoline fused [1,3]oxazines were efficiently synthesized from Diels-Alder reaction of N-arylmaleimides with 1,2-dihydro-2-oxospiro[3H-indole-3,2＇-[2H,9aH-pyrido[2,1-b][l,3]oxazines], which were generated in situ from three-component reactions of substituted pyridines and isatins with methyl propiolate, or di- methyl acetylenedicarboxylate. The stereochemistry of the products was clearly clarified by the analysis of 1H NMR data and single crystal structures of the obtained polycyclic compounds.

关键词： Diels-Alder reaction one-pot reaction diastereoselectivity spirooxindole oxazine maleimide

Generation of Methyl Vinyl Ketone from Oxidation of Levulinic Acid Oxidized by Cupric Oxide Complex

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

Chinese Journal of Chemistry 2012年第2期30卷 327-332页

作者： gong,yan Lin,Lu Zhang,Beixiao Department of Resources Science and Engineering State Key Lab of Pulp and Paper EngineeringSouth China University of TechnologyGuangzhouGuangdong 510640China Sehool of Energy Research Xiamen UniversityXiamenFujian 361005China

Methyl vinyl ketone （MVK） is a kind of high-value chemical which has been widely used in many fields. In this paper, it is formed from oxidation of levulinic acid--a hydrolysis product of biomass. Copper oxide supported on cerium dioxide （CuO/CeO2） and alumina （CuO/AI203） were prepared and used for the oxidation of levulinic acid （LA）. The oxidants were characterized by means of X-ray diffraction （XRD）, H2-temperature programmed reduction （H2-TPR） and atomic force microscope （AFM） techniques. CuO/CeO2 and CuO/A1203 show a different behav- ior with respect to pure CuO. The experiments revealed that CuO/CeO2 and CuO/AI203 can oxidize LA and get methyl vinyl ketone [yield of 15.5% detected by head space-gas chromatograph-mass spectrometer （HS-GC-MS）] under mild reactive conditions, while pure CuO oxidizes LA to produce butanone （MEK）.

关键词： LA oxidation MVK copper oxide cerium dioxide alumina

The silicate and carbon-rich models of CoRoT-7b,Kepler-9d and Kepler-10b

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

Research in Astronomy and Astrophysics 2012年第6期12卷 678-692页

作者： yan-Xiang gong Ji-Lin Zhou Department of Astronomy ＆ Key Laboratory of Modern Astronomy and Astrophysics inMinistry of Education Nanjing University Nanjing 210093 China College of Physics and Electronic Engineering Taishan University Taian 271021 China

Possible bulk compositions of the super-Earth exoplanets CoRoT-7b, Kepler-9d, and Kepler-10b are investigated by applying a commonly used silicate model and a non-standard carbon model. Their internal structures are deduced using a suitable equation of state for the materials. The degeneracy problems of their compo- sitions can be partly overcome, based on the fact that all three planets are extremely close to their host stars. By analyzing the numerical results, we conclude： 1） the iron core of CoRoT-7b is not more than 27% of its total mass within lc~ mass-radius error bars, so an Earth-like composition is less likely, but its carbon rich model can be com- patible with an Earth-like core/mantle mass fraction; 2） Kepler-10b is more likely to have a Mercury-like composition, with its old age implying that its high iron content may be a result of strong solar wind or giant impact; 3） the transiting-only super-Earth Kepler-9d is also discussed. Combining its possible composition with the formation theory, we can place some constraints on its mass and bulk composition.

关键词： planets and satellites: general -- methods: numerical -- planets andsatellites: individual (CoRoT-7b Kepler-9d Kepler- 10b)

A NEW FINITE ELEMENT APPROXIMATION OF A STATE-CONSTRAINED OPTIMAL CONTROL PROBLEM

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2009年第1期27卷 97-114页

作者： wenbin Liu Wei gong Ningning yan KBS Institute of Mathematics and Statistics The University of Kent Canterbury CT2 7NF England LSEC Institute of Systems Science Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China

In this paper, we study numerical methods for an optimal control problem with pointwise state constraints. The traditional approaches often need to deal with the deltasingularity in the dual equation, which causes many difficulties in its theoretical analysis and numerical approximation. In our new approach we reformulate the state-constrained optimal control as a constrained minimization problems only involving the state, whose optimality condition is characterized by a fourth order elliptic variational inequality. Then direct numerical algorithms （nonconforming finite element approximation） are proposed for the inequality, and error estimates of the finite element approximation are derived. Numerical experiments illustrate the effectiveness of the new approach.

关键词： Optimal control problem State-constraints Fourth order variational inequalities Nonconforming finite element method.

Heat Treatment of Spray Deposition SiCp/6066 Aluminum Matrix Composites

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2000年第2期12卷 61-64页

作者： gong Hao-ran Li wen-xian Department of Materials Science and Engineering Central South University of TechnologyChangsha 410083China

Heat treatment of spray deposition 10% SiCp/6066 ( φ (SiCp)=10%) composites was investigated by means of hardness measurement. The results show that heat treatment technology is influenced by the presence of SiC particles. Compared with the base alloy 6066, the composites have lower burning temperature and is burnt at 540 ℃ due to the enrichment of Mg and Cu atoms in the SiCp/6066 interfaces. As a result, solution treatment of the composites should be carried out at lower temperature. The aging parameter values such as the aging temperature, the precipitation temperature of β′ and β phases, as well as the peak aging time, become lower. The optimum heat treatment process conditions are that the composites are solution treated at 515 ℃ and aged at 165 ℃ for 5 h.

关键词： spray deposition composites solution treatment temperature aging

Storage of Entangled States with Multiple Trapped Ions in Thermal Motion

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2006年第4期45卷 605-608页

作者： gong Xiao-Long yanG wen-Xing Department of Physics Yangtze University Jingzhou 434100 China Department of Physics Huazhong University of Science and Technology Wuhan 430074 China Wuhan Institute of Physics and Mathematics the Chinese Academy of Sciences Wuhan 430071 China

This paper presents an alternative scheme to realize the storage of entangled states for multiple trapped ions including W state, Bell states, and GHZ states even with ions which exchange vibrational energy with a heating surrounding, Our scheme requires that the ions be simultaneously excited by two laser beams with different frequencies. In this scheme the vibrational degrees of freedom are only regarded as intermediate states and the ions exchange energy via the mediation of the vibration of the vibrational mode in coupling processes. The scheme is insensitive to both the initial vibrational state and heating if the system remains in the Lamb Dicke regime. Since the effective Rabi frequency has a small dependence on the vibrational quantum number the heating will have no direct, effect on the internal state evolution.

关键词： entangled state storage trapped ions

Removal of Fulvic Acids from Aqueous Solutions via Surfactant Modified Zeolite

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2006年第5期22卷 566-570页

作者： WANG Shu-guang gong wen-xin LIU Xian-wei GAO Bao-yu YUE Qin-yan ZHANG Dong-hua School of Environmental Science and Engineering Shandong University Jinan 250100 P. R. China

A surfactant modified zeolite（ SMZ）, i. e. , a zeolite modified by using hexadecyl trimethyl ammonium bromide （HDTMA） was used to remove fulvic acids（FA） from aqueous solution. The effects of the relevant parameters, such as the loading level of HDTMA, the contact time, the initial FA concentration, the pH, and the types of the metal carious and organics were examined. The results show that SMZ with an HDTMA loading-level of 120% of the external cation exchange capacity（ECEC） of zeolite exhibits the best performance. Although the removal of fulvic acids by SMZ occurs rapidly within the first 30 min of the contact time, a contact time of at least 4 h is required to attain the adsorption equilibrium. The removal capacity of FA by SMZ decreases with the increase of the initial FA concentration. The pH has an effect on the FA removal efficiency because it can influence the characteristics of the FA molecules. The removal of FA is considerably enhanced by Ca^2＋ or Mg^2＋ ions and is adversely affected by phenol or pentachlorophenol（PCP）. Under the optimum conditions, 98% of FA could be removed by SMZ. Furthermore, the desorption of FA and the regeneration of SMZ were studied. The results show that a 30% ethanol solution is sufficient for the regeneration of SMZ.

关键词： Surfactant modified zeolite(SMZ) Fulvic acids(FA) removal Adsorption Desorption

Evolution of electromechanical properties in Fe-doped(Pb,Sr)(Zr,Ti)O_(3) piezoceramics

在线全文

学校读者我要写书评

暂无评论

Journal of Advanced Ceramics 2021年第3期10卷 587-595页

作者： Chuan CHEN yan WANG Zong-Yue LI Chun LIU wen gong Qing TAN Bing HAN Fang-Zhou YAO Ke WANG Joint Laboratory of Electric Power Intelligent Sensing Technology and Application Department of Sensing Technology for Electric PowerGlobal Energy Interconnection Research Institute Co.Ltd.Future Science ParkBeijing 102209China China Aerospace Science and Industry Corporation Beijing 100048China Naqu Branch of Tibet Electric Limited Company Naqu 852000China State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China Center of Advanced Ceramic Materials and Devices Yangtze Delta Region Institute of Tsinghua UniversityZhejiang 314006China Beijing Advanced Innovation Center for Materials Genome Engineering State Key Laboratory for Advanced Metals and MaterialsUniversity of Science and Technology BeijingBeijing 100083China Department of Orthodontics&National Engineering Laboratory for Digital and Material Technology Peking University School and Hospital of StomatologyBeijing 100081China State Key Laboratory for Mechanical Behavior of Materials Xi'an Jiaotong UniversityXi'an 710049China Foshan(Southern China)Institute for New Materials Foshan 528200China

Defects in acceptor-doped perovskite piezoelectric materials have a significant impact on their electrical ***,the defect mediated evolution of piezoelectric and ferroelectric properties of Fe-doped(Pb,Sr)(Zr,Ti)O_(3)(PSZT-Fe)piezoceramics with different treatments,including quenching,aging,de-aging,and poling,was investigated *** vacancies with a cubic symmetry are preserved in the quenched PSZT-Fe ceramics,rendering them robust ferroelectric *** the aged PSZT-Fe polycrystals,defect dipole between Fe dopant and oxygen vacancy has the same orientation with spontaneous polarization Ps,which enables the reversible domain switching and hence leads to the emergence of pinched polarization hysteresis and recoverable strain *** the defect dipoles can be gradually disrupted by bipolar electric field cycling,once again endowing the aged materials with representative ferroelectric *** the poled PSZT-Fe polycrystals,the defect dipoles are reoriented to be parallel to the applied poling field,and an internal bias field aligning along the same direction emerges simultaneously,being responsible for asymmetric hysteresis loops.

关键词： lead-zirconate-titanate(PZT) piezoelectric acceptor defect engineering electromechanical properties

Insight into the oxidative desulfurization of high-sulfur petroleum coke under mild conditions:a journey of vanadium-substituted Dawson-type phosphotungstic acid

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2021年第3期18卷 983-993页

作者： Fu-Min Li Ming-Qing Hua yan-Chen Wei Ji-Xing Liu Jia-Hong gong Chao Wang Pei-wen Wu yan Huang Hua-Ming Li wen-Shuai Zhu School of Chemistry and Chemical Engineering Jiangsu UniversityZhenjiang 212013China School of Materials Science and Engineering Jiangsu UniversityZhenjiang 212013China School of the Environment and Safety Engineering Jiangsu UniversityZhenjiang 212013China

High-sulfur petroleum coke(HSPC),that is a by-product from slag oil in the coking process of refning,shows versatility values in practical applications and,however,concentrates the majority of organic ***,we design and construct a highly efective CTAB@HPA composites to be explored for the catalytic oxidative desulfurization of HSPC under mild conditions using hydrogen peroxide as the oxidant and 1-butyl-3-methylimidazole tetrafuoroborate ionic liquid as the *** results demonstrate that the sulfur content of HSPC could be strikingly reduced from 4.46 wt%to 2.48 wt%under 60℃ and atmospheric pressure,and that the organic sulfur in HSPC is mainly oxidized to sulfoxide,sulfone and sulfate,which latter can be directly separated from petroleum ***,the efect of reaction conditions on the desulfurization performance of HSPC as well as the catalytic oxidation reaction kinetic of HSPC desulfurization was systematically ***,a mechanism for the oxidative desulfurization of HSPC over CTAB@HPA catalysts was ***,this work provides new insight into how to construct active catalysts for the desulfurization of HSPC under mild conditions.

关键词： High-sulfur petroleum coke Dawson-type phosphotungstic acid Oxidative desulfurization Mild conditions Sulfate