期刊文献+
共找到3,055篇文章
< 1 2 153 >
每页显示 20 50 100
Scalable solid-phase synthesis of defect-rich graphene for oxygen reduction electrocatalysis 被引量:1
1
作者 Chunxiao Dong Li Yang +4 位作者 Cheng Lian Xiaoling Yang Yihua Zhu Hongliang Jiang Chunzhong Li 《Green Energy & Environment》 SCIE EI CSCD 2023年第1期224-232,共9页
Defect-engineered carbon materials have been emerged as promising electrocatalysts for oxygen reduction reaction(ORR)in metal-air batteries.Developing a facile strategy for the preparation of highly active nanocarbon ... Defect-engineered carbon materials have been emerged as promising electrocatalysts for oxygen reduction reaction(ORR)in metal-air batteries.Developing a facile strategy for the preparation of highly active nanocarbon electrocatalysts remains challenging.Herein,a low-cost and simple route is developed to synthesize defective graphene by pyrolyzing the mixture of glucose and carbon nitride.Molecular dynamics simulations reveal that the graphene formation is ascribed to two-dimensional layered feature of carbon nitride,and high compatibility of carbon nitride/glucose systems.Structural measurements suggest that the graphene possesses rich edge and topological defects.The graphene catalyst exhibits higher power density than commercial Pt/C catalyst in a primary Zn-air battery.Combining experimental results and theoretical thermodynamic analysis,it is identified that graphitic nitrogen-modified topological defects at carbon framework edges are responsible for the decent ORR performance.The strategy presented in this work can be can be scaled up readily to fabricate defective carbon materials. 展开更多
关键词 Carbon materials ELECTROCATALYSIS Oxygen reduction reaction solid-phase synthesis Zn-air battery
下载PDF
Study on trifluoromethanesulfonic acid-promoted synthesis of daidzein: Process optimization and reaction mechanism
2
作者 Hai Cao Haibin Yang +3 位作者 Yanxiong Fang Yuandi Zeng Xiaolan Cai Jingjing Ma 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第7期132-139,共8页
Daidzein has been widely used in pharmaceuticals,nutraceuticals,cosmetics,feed additives,etc.Its preparation process and related reaction mechanism need to be further investigated.A cost-effective process for synthesi... Daidzein has been widely used in pharmaceuticals,nutraceuticals,cosmetics,feed additives,etc.Its preparation process and related reaction mechanism need to be further investigated.A cost-effective process for synthesizing daidzein was developed in this work.In this article,a two-step synthesis of daidzein(Friedel–Crafts acylation and[5+1]cyclization)was developed via the employment of trifluoromethanesulfonic acid(TfOH)as an effective promoting reagent.The effect of reaction conditions such as solvent,the amount of TfOH,reaction temperature,and reactant ratio on the conversion rate and the yield of the reaction,respectively,was systematically investigated,and daidzein was obtained in 74.0%isolated yield under optimal conditions.Due to the facilitating effect of TfOH,the Friedel–Crafts acylation was completed within 10 min at 90℃ and the[5+1]cyclization was completed within 180 min at 25℃.In addition,a possible reaction mechanism for this process was proposed.The results of the study may provide useful guidance for industrial production of daidzein on a large scale. 展开更多
关键词 synthesis Optimal design chemical processes Reaction mechanism
下载PDF
Natural forests exhibit higher organic carbon concentrations and recalcitrant carbon proportions in soil than plantations:a global data synthesis
3
作者 Xiuqing Nie Hui Wang +1 位作者 Jian Wang Shirong Liu 《Journal of Forestry Research》 SCIE EI CAS CSCD 2024年第5期131-141,共11页
Different chemical compositions of soil organic carbon(SOC)affect its persistence and whether it signifi-cantly differs between natural forests and plantations remains unclear.By synthesizing 234 observations of SOC c... Different chemical compositions of soil organic carbon(SOC)affect its persistence and whether it signifi-cantly differs between natural forests and plantations remains unclear.By synthesizing 234 observations of SOC chemical compositions,we evaluated global patterns of concentra-tion,individual chemical composition(alkyl C,O-alkyl C,aromatic C,and carbonyl C),and their distribution even-ness.Our results indicate a notably higher SOC,a markedly larger proportion of recalcitrant alkyl C,and lower easily decomposed carbonyl C proportion in natural forests.How-ever,SOC chemical compositions were appreciably more evenly distributed in plantations.Based on the assumed con-ceptual index of SOC chemical composition evenness,we deduced that,compared to natural forests,plantations may have higher possible resistance to SOC decomposition under disturbances.In tropical regions,SOC levels,recalcitrant SOC chemical composition,and their distributed evenness were significantly higher in natural forests,indicating that SOC has higher chemical stability and possible resistance to decomposition.Climate factors had minor effects on alkyl C in forests globally,while they notably affected SOC chemi-cal composition in tropical forests.This could contribute to the differences in chemical compositions and their distrib-uted evenness between plantations and natural stands. 展开更多
关键词 Global data synthesis Natural forest Plantations Soil organic carbon Soil organic carbon chemical composition
下载PDF
Thermodynamics for chemical vapor synthesis of Nb nanopowder in NbCl_5-H_2-Ar system
4
作者 朱骏 黄凯 +1 位作者 侯军刚 朱鸿民 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第12期3987-3993,共7页
Thermodynamics for chemical vapor synthesis (CVS) of Nb nanopowder in NbCl5-H2-Ar system was investigated by using FactSage software. The validation experiments were conducted to confirm the thermodynamics points. T... Thermodynamics for chemical vapor synthesis (CVS) of Nb nanopowder in NbCl5-H2-Ar system was investigated by using FactSage software. The validation experiments were conducted to confirm the thermodynamics points. The results indicate that under the atmospheric pressure, the reduction approach from NbCl5(g) to Nb(s) is a stage-wise process with the formation of complex sub-chlorides, and is controllable at low hydrogen ratio (mole ratio of n(NbCl5):n(H2)&lt;1:180) and low temperature (&lt;1050 &#176;C). Furthermore, a reasonable amount of inert loading gas is favorable to increase the reduction ratio of NbCl5 and the powder yield. The as-synthesized Nb nanopowder with the homogeneous size of 30-50 nm and the powder yield of 85% (mass fraction) is obtained by the CVS process under n(NbCl5):n(H2):n(Ar)=1:120:1 and 950 &#176;C with the NbCl5 reduction rate of 96.1%. 展开更多
关键词 NbCl5-H2-Ar system chemical vapor synthesis (CVS) thermodynamic niobium nanopowder FactSage software
下载PDF
Research Progress on Synthesis of Superoxide Dismutase Mimics
5
作者 Delong Bao Xiao Han Anhe Jia 《Expert Review of Chinese Chemical》 2024年第2期15-22,共8页
Research on the synthesis of superoxide dismutase mimics by chemical and biologi-cal synthetic methods were reviewed.The advantages and limitations were analyzed.A prospect for the future development of superoxide dis... Research on the synthesis of superoxide dismutase mimics by chemical and biologi-cal synthetic methods were reviewed.The advantages and limitations were analyzed.A prospect for the future development of superoxide dismutase mimics is proposed. 展开更多
关键词 superoxide dismutase chemical synthesis biological synthesis REVIEW
下载PDF
Synthesis and Characterization of Y-Doped Mesoporous CeO_2 Using A Chemical Precipitation Method 被引量:5
6
作者 宋晓岚 江楠 +2 位作者 李宇焜 徐大余 邱冠周 《Journal of Rare Earths》 SCIE EI CAS CSCD 2007年第4期428-433,共6页
Using cetyltrimethylammonium bromide (CTAB) as the template agent, cerium nitrate as the cerium resource, yttrium nitrate as the yttrium resource, and ammonium carbonate as the precipitating agent, mesoporous CeO2 p... Using cetyltrimethylammonium bromide (CTAB) as the template agent, cerium nitrate as the cerium resource, yttrium nitrate as the yttrium resource, and ammonium carbonate as the precipitating agent, mesoporous CeO2 powders doped with different yttrium contents were successfully synthesized using a chemical precipitation method, under an alkalescent condition. Properties of the obtained samples were characterized and analyzed with X-ray diffraction (XRD), energy dispersive analysis of X-rays (EDAX), transmission electron microscopy (TEM), infrared (IR) absorbance, and the BET method. For the prepared samples with 20% (molar ratio) Y-doped content, a BET specific surface area of 106. 6 m^2 · g^- 1, with an average pore size of3~27 nm were obtained. XRD patterns showed that the doped samples were with a cubic fluorite structure. TEM micrographs revealed that the doped samples showed a spherical morphology with a diameter ranging from 20 to 30 nm and a round pore shape. IR results indicated that the Ce-O-Ce vibration intensity decreased as the Y-doped content increased. N2 adsorption-desorption isotherms showed that the samples possessed typical mesopore characteristics. The average pore size of the samples decreased alter mesoporous CeO2 was doped with yttrium, and the average pore size decreased largely as the Y-doped content increased. 展开更多
关键词 mesoporous ceria Y-doped chemical precipitation method synthesis characterization rare earths
下载PDF
Synthesis of a highly hydrophobic cyclic decapeptide by solid-phase synthesis of linear peptide and cyclization in solution 被引量:5
7
作者 Chen, Jian Zhang, Bei +2 位作者 Xie, Cao Lu, Yi Wu, Wei 《Chinese Chemical Letters》 SCIE CAS CSCD 2010年第4期391-394,共4页
A general method was described to synthesize a highly hydrophobic cyclic peptide,cyclo[LWLWLWLWLQ]where underlines indicate D-configuration of the amino acid,by a two-step solid-phase/solution synthesis strategy.The l... A general method was described to synthesize a highly hydrophobic cyclic peptide,cyclo[LWLWLWLWLQ]where underlines indicate D-configuration of the amino acid,by a two-step solid-phase/solution synthesis strategy.The linear decapeptide was assembled by standard Boc chemistry on solid-phase and subsequently cyclized in solution with high efficiency and reproducibility. In subsequent purification by semi-preparative HPLC,50%(v/v) DMF/H_2O was employed as the solvent to overcome the difficulty of solubilization... 展开更多
关键词 Cyclic peptide Decapeptide cyclo[LWLWLWLWLQ] solid-phase synthesis CYCLIZATION PURIFICATION
下载PDF
Synthesis of steel slag ceramics: chemical composition and crystalline phases of raw materials 被引量:3
8
作者 Li-hua Zhao Wei Wei +2 位作者 Hao Bai Xu Zhang Da-qiang Cang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2015年第3期325-333,共9页
Two types of porcelain tiles with steel slag as the main raw material (steel slag ceramics) were synthesized based on the CaO-A1203-SiO2 and CaO--MgO-SiO2 systems, and their bending strengths up to 53.47 MPa and 99.... Two types of porcelain tiles with steel slag as the main raw material (steel slag ceramics) were synthesized based on the CaO-A1203-SiO2 and CaO--MgO-SiO2 systems, and their bending strengths up to 53.47 MPa and 99.84 MPa, respectively, were obtained. The presence of anorthite, a-quartz, magnetite, and pyroxene crystals (augite and diopside) in the steel slag ceramics were very different from the composition of traditional ceramics. X-ray diffraction (XRD) and electron probe X-ray microanalysis (EPMA) results illustrated that the addition of steel slag reduced the temperature of extensive liquid generation and further decreased the firing temperature. The considerable contents of glass-modifying oxide liquids with rather low viscosities at high temperature in the steel slag ceramic adobes promoted element diffusion and crystallization. The results of this study demonstrated a new approach for extensive and effective recycling of steel slag. 展开更多
关键词 ceramic materials synthesis steel slag chemical composition crystalline phases solid waste recycling
下载PDF
Solid-phase synthesis of Cu2MoS4 nanoparticles for degradation of methyl blue under a halogen-tungsten lamp 被引量:4
9
作者 Shi-na Li Rui-xin Ma Cheng-yan Wang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2018年第3期310-314,共5页
The Cu_2MoS_4 nanoparticles were prepared using a relatively simple and convenient solid-phase process, which was applied for the first time. The crystalline structure, morphology, and optical properties of Cu_2MoS_4 ... The Cu_2MoS_4 nanoparticles were prepared using a relatively simple and convenient solid-phase process, which was applied for the first time. The crystalline structure, morphology, and optical properties of Cu_2MoS_4 nanoparticles were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, and UV-vis spectrophotometry. Cu_2MoS_4 nanoparticles having a band gap of 1.66 eV exhibits good photocatalytic activity in the degradation of methylene blue, which indicates that this simple process may be critical to facilitate the cheap production of photocatalysts. 展开更多
关键词 Cu2MoS4 NANOPARTICLES solid-phase synthesis DEGRADATION PHOTOCATALYST METHYL blue
下载PDF
Fischer–Tropsch synthesis using Co and Co-Ru bifunctional nanocatalyst supported on carbon nanotube prepared via chemical reduction method 被引量:2
10
作者 Jafar Shariati Ali Haghtalab Amir Mosayebi 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2019年第1期9-22,共14页
We used a chemical reduction method to synthesize the catalysts of cobalt(Co) and cobalt-ruthenium(Co-Ru) bifunctional supported on carbon nanotubes(CNTs) for Fischer–Tropsch synthesis(FTS) in a fixedbed reactor. The... We used a chemical reduction method to synthesize the catalysts of cobalt(Co) and cobalt-ruthenium(Co-Ru) bifunctional supported on carbon nanotubes(CNTs) for Fischer–Tropsch synthesis(FTS) in a fixedbed reactor. These Co-Ru/CNTs catalysts were synthesized with various weight proportions of Ru/Co(0.1 to 0.4 wt%) with keeping a fixed amount of cobalt(10 wt%). Moreover, for comparison purpose, CNTs supported Co-and Co(Ru)-based catalysts at same loading as the above catalysts were prepared through impregnation method. We characterize the present catalysts through the various techniques such as Energy–dispersive X-ray(EDX), Transmission Electron Microscopy(TEM), Brunauer–Emmett–Teller(BET),Hydrogen-Temperature-Programmed Reduction(H_2-TPR), Hydrogen-Temperature-Programmed Desorption(H_2-TPD) and O_2 titration. Thus using the chemical reduction method, a narrow particle size distribution was obtained so that the small cobalt particles were confined inside the CNTs. The Co-based catalyst prepared by impregnation was compared with the Co-Ru catalysts at the same loading. The results demonstrated that the use of chemical reduction method led to decrease the average Co oxide cluster size to8.7 nm so that the reduction enhanced about 24% and stabilized an earlier time at the stream. Among the prepared catalysts, the results indicated that the Co-Ru/CNTs catalysts demonstrated high catalytic activity with the highest long-chain hydrocarbons(C_(5+)), selectivity up to 74.76%, which was higher than those we obtained by the Co-Ru/γ-Al_2O_3(61._20%), Co/CNTs(43.68%) and Co/γ-Al_2O_3(37.69%). At the same time, comparing with those catalyst synthesized by impregnation, the use of chemical reduction led to enhancement of the C_(5+) selectivity from 59.30% to 68.83% and increment in FTS rate about 11% for the Co-Ru/CNTs catalyst. 展开更多
关键词 Cobalt-ruthenium Carbon nanotubes FISCHER-TROPSCH synthesis Catalyst nanoparticles chemical reduction method
下载PDF
Chemical synthesis of nanocrystalline ZrO_2-SnO_2 composite powders 被引量:1
11
作者 YANG Huaming ZHANG Xiangchao +2 位作者 YANG Wuguo HUANG Chenghuan QIU Guanzhou Department of Inorganic Materials, School of Resources Processing and Bioengineering, Central South University, Changsha 410083, China 《Rare Metals》 SCIE EI CAS CSCD 2004年第2期182-184,共3页
ZrO_2-SnO_2 composite nanoparticles were prepared by heating the hydrateprecursors synthesized by the chemical co-precipitation reaction of ZrOCl_2 and SnCl_4. Theprecursors were examined by differential thermal analy... ZrO_2-SnO_2 composite nanoparticles were prepared by heating the hydrateprecursors synthesized by the chemical co-precipitation reaction of ZrOCl_2 and SnCl_4. Theprecursors were examined by differential thermal analysis (DTA) and thermogravimetric analysis(TGA). The composite powder was characterized using X-ray diffraction (XRD), transmission electronmicroscopy (TEM) and desorption isotherm (Barrett-Joyner-Halenda method). The average crystal sizeof the nanoparticle ranges from 15 to 30 nm for the sample containing 5%-25% ZrO_2 (mass fraction).Most of the pores in the ZrO_2-SnO_2 nanoparticles are about 10-20 nm in diameter. The compositepowder is promising for chemical sensors. 展开更多
关键词 inorganic materials ZrO_2-SnO_2 nanocomposites chemical synthesis DOPING pore structure
下载PDF
Preparation and characterization of calcium aluminate by chemical synthesis 被引量:1
12
作者 Feng Chen Yanruo Hong +1 位作者 Jialin Sun Jinglong Bu 《Journal of University of Science and Technology Beijing》 CSCD 2006年第1期82-86,共5页
Saturated Ca(OH)2 and AlCl3 solutions were used to synthesize calcium aluminate hydrate precipitates at room temperature; high purity calcium aluminate powders with stable phases were made by calcination of the prec... Saturated Ca(OH)2 and AlCl3 solutions were used to synthesize calcium aluminate hydrate precipitates at room temperature; high purity calcium aluminate powders with stable phases were made by calcination of the precursors at a temperature as low as 1100℃. PSD and BET analysis revealed the particles with sizes ranging from submicrometer to several micrometers and with a specific area of 13 m^2/g. The measurement of hydraulic exotherm revealed that the exothennal rate is in peak for about 2 h. The exothermal quantities are 449.24 J/g at 12 h and 488.38 J/g at 24 h. Its strength development is quick and the 1 day curing strength is almost equal to 100% of the 3 days curing strength in the mortar test. 展开更多
关键词 calcium aluminate PREPARATION CHARACTERIZATION chemical synthesis
下载PDF
Synthesis of Cell Adhesive Motif RGD Tripeptide by a Novel Chemical Method and Its Purification 被引量:1
13
作者 WANG Hua ZHAO Mi-feng +6 位作者 MA Cheng-yun JING Wei HUANG Yi-bing HOU Rui-zhen ZENG Hong-bin XU Li ZHANG Xue-zhong 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2006年第5期612-616,共5页
The cell adhesive motif RGD tripeptide was synthesized by using a novel chemical method. First, Gly-Asp(GD) was synthesized in two steps including the chloroacetylation of free L-aspartic acid and the ammonolysis of... The cell adhesive motif RGD tripeptide was synthesized by using a novel chemical method. First, Gly-Asp(GD) was synthesized in two steps including the chloroacetylation of free L-aspartic acid and the ammonolysis of the chloroacetylated L-aspartic acid. The yield of chloroacetylated L-aspartic acid was 83.0%. For the ammonolysis of chloroacetylated L-aspartic acid, the yield of the ammonolyzed product was 92. 3%. Second, the coupling between Arg and Gly-Asp was carried out by using the NCA method. The maximum yield of RGD was about 50% at 0℃ and pH = 9. 5. The prepared RGD tripeptide was confirmed by using amino acid component analysis and mass spectrographic analysis. 展开更多
关键词 RGD tripeptide chemical synthesis Purification Arg-Gly-Asp
下载PDF
Atomic Level Dispersed Metal–Nitrogen–Carbon Catalyst toward Oxygen Reduction Reaction: Synthesis Strategies and Chemical Environmental Regulation 被引量:3
14
作者 Hengbo Yin Huicong Xia +3 位作者 Shuyan Zhao Kexie Li Jianan Zhang Shichun Mu 《Energy & Environmental Materials》 SCIE CSCD 2021年第1期5-18,共14页
For development and application of proton exchange membrane fuel cell(PEMFC) energy transformation technology, the cost performance must be elevated for the catalyst. At present, compared with noble metal-based cataly... For development and application of proton exchange membrane fuel cell(PEMFC) energy transformation technology, the cost performance must be elevated for the catalyst. At present, compared with noble metal-based catalysts, such as Pt-based catalysts, atomically dispersed metal–nitrogen–carbon(M–N–C) catalysts are popularity and show great potential in maximizing active site density, high atom utilization and high activity,making them the first choice to replace Pt-based catalysts. In the preparation of atomically dispersed metal–nitrogen–carbon catalyst, it is difficult to ensure that all active sites are uniformly dispersed, and the structure system of the active sites is not optimal. Based on this, we focus on various approaches for preparing M–N–C catalysts that are conducive to atomic dispersion, and the influence of the chemical environmental regulation of atoms on the catalytic sites in different catalysts. Therefore, we discuss the chemical environmental regulation of the catalytic sites by bimetals, atom clusters, and heteroatoms(B, S, and P). The active sites of M–N–C catalysts are explored in depth from the synthesis and characterization, reaction mechanisms, and density functional theory(DFT)calculations. Finally, the existing problems and development prospects of the current atomic dispersion M–N–C catalyst are proposed in detail. 展开更多
关键词 atomic-level catalyst chemical environmental effects metal-nitrogen-carbon oxygen reduction reaction synthesis strategy
下载PDF
Solid-phase Synthesis of PNA Monomer by Ugi Four-component Condensation Reaction 被引量:2
15
作者 WenHaoWANG XiaoMinZOU XinZHANG YiQiuFU PingXU 《Chinese Chemical Letters》 SCIE CAS CSCD 2005年第5期585-588,共4页
Peptide nucleic acids (PNA) oligomers were synthesized in most cases by peptide synthesis from N-protected monomers. In this work a new method of obtaining PNA monomer by Ugi four-component condensation reaction was t... Peptide nucleic acids (PNA) oligomers were synthesized in most cases by peptide synthesis from N-protected monomers. In this work a new method of obtaining PNA monomer by Ugi four-component condensation reaction was tested by solid-phase synthesis. The Fmoc protected PNA monomer was build up with thymin-1-yl acetic acid, 3-methylbutyl aldehyde, Fmoc protected aminoethyl isocyanide and Gly-Wang resin. 展开更多
关键词 Peptide nucleic acids (PNA) Ugi four-component condensation reaction (U-4CR) solid-phase synthesis Isocyanide.
下载PDF
Solid-phase Synthesis of Acyl-plasminogen-Streptokinase Activator Composite(APSAC) and Its Thrombolytic Properties 被引量:1
16
作者 TENGLi-rong LIANGFang +4 位作者 SUNHong QINYi HONGShui-sheng CHENJia LIULan-ying 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2004年第5期584-587,共4页
The dialysis method has been traditionally used for the conversion of native human plasminogen(Glu-Hpg) to lys-plasminogen(Lys-Hpg). Here is described a solid-phase synthesis method for the preparation of an acyl-plas... The dialysis method has been traditionally used for the conversion of native human plasminogen(Glu-Hpg) to lys-plasminogen(Lys-Hpg). Here is described a solid-phase synthesis method for the preparation of an acyl-plasminogen-streptokinase activator complex(APSAC) from Lys-Hpg, streptokinase(SK) and chemical modification (agent(4-amidinophenyl-4′-aminobenzoate hydrochloride)) with the L-lysine-Sepharose 4B Column as the carrier. The new method significantly increases the product yield and purity over the liquid-phase methods. The APSAC prepared with the new method exhibits a significant thrombolytic effect with a long half-life of about 8.8 h in rabbits. 展开更多
关键词 Acyl-plasminogen-streptokinase activator complex(APSAC) solid-phase synthesis THROMBOLYTIC
下载PDF
Hydrothermal Synthesis,Crystal Structure,Spectrum Properties and Quantum Chemical Calculation of a Trinuclear Copper(Ⅱ) Complex with 3-(Pyridin-2-yl)-1,2,4-triazole 被引量:1
17
作者 李昶红 李薇 +1 位作者 李玉林 杨颖群 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2012年第8期1089-1094,共6页
A three-dimensional framework copper(Ⅱ) coordination polymer with copper carbonate basic and 3-(pyridin-2-yl)-1,2,4-triazole (Hpt) has been hydrothemally synthesized.The complex (2,C14 H10 CuN8 ·3H2 O) c... A three-dimensional framework copper(Ⅱ) coordination polymer with copper carbonate basic and 3-(pyridin-2-yl)-1,2,4-triazole (Hpt) has been hydrothemally synthesized.The complex (2,C14 H10 CuN8 ·3H2 O) crystallizes in tetragonal,space group P4 2 /n,a=2.08581(12),b=2.08581(12),c=0.72331(4) nm,M r=761.73,V=3.1468(3) nm 3,Dc=1.608 g/cm 3,Z=4,F(000)=1552,GOOF=1.07,R=0.0515 and wR=0.1689.Every asymmetric unit molecular structure of the complex is composed with one copper ion,one and half water molecules and two Hpt molecules.Each copper ion is coordinated with five nitrogen atoms from four Hpt molecules,forming a distorted square pyramidal geometry.The fluorescence spectrum analysis shows that the title complex at room temperature exhibits intense photoluminescence with maximum emission at 450 nm.The quantum chemistry calculation study on the complex has been performed.The stability,some frontier molecular orbital energies and composition characteristics of some frontier molecular orbitals of the complex have been investigated. 展开更多
关键词 trinuclear copper complex hydrothermal synthesis spectrum properties quantum chemical calculation
下载PDF
Thermodynamic Analysis and Synthesis Gas Generation by Chemical-Looping Gasification of Biomass with Nature Hematite as Oxygen Carriers 被引量:2
18
作者 Zhen Huang Fang He +5 位作者 Anqing Zheng Kun Zhao Sheng Chang Xinai Li Haibin Li Zengli Zhao 《Journal of Sustainable Bioenergy Systems》 2013年第1期33-39,共7页
Thermodynamic parameters of chemical reactions in the system were carried out through thermodynamic analysis. According to the Gibbs free energy minimization principle of the system, equilibrium composition of the rea... Thermodynamic parameters of chemical reactions in the system were carried out through thermodynamic analysis. According to the Gibbs free energy minimization principle of the system, equilibrium composition of the reactions of chemical-looping gasification (CLG) of biomass with natural hematite (Fe2O3) as oxygen carrier were analyzed using commercial software of HSC Chemistry 5.1. The feasibility of the CLG of biomass with hematite was experimental verified in a lab-scale bubbling fluidized bed reactor using argon as fluidizing gas. It was indicated the experimental results were consistent with the theoretical analysis. The presence of oxygen carrier gave a significant effect on the biomass conversion and improved the synthesis gas yield obviously. It was observed that the gas content of CO and H2 was over 70% in CLG of biomass. The reduced hematite particles mainly existed in form of FeO. It was showed that the reduction of natural hematite with biomass proceeds in a stepwise manner from Fe2O3 →Fe3O4→ FeO. Reduction product of natural hematite can be restored the lattice oxygen by oxidation with air. 展开更多
关键词 THERMODYNAMICS synthesis Gas Natural HEMATITE Oxygen Carriers BIOMASS chemical LOOPING GASIFICATION
下载PDF
Use of Magic Angle Spinning ~1H NMR Spectroscopy to Monitor Reactions in Solid-Phase Synthesis 被引量:1
19
作者 Ai Ming YU Hua Zheng YANG(The State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071)Ping Chuan SUN +1 位作者 Zhen Pu ZHANG Ming LI(The State Key Laboratory of Functional Polymeric Materials for Adsorption and Separation,Nankai Uni 《Chinese Chemical Letters》 SCIE CAS CSCD 1997年第12期0-0,共2页
Proton NMR-spectra of Wang resin bound compounds were obtained using the magic angle spinning 1HNMR technique with standard equipment. It was possible to analyse the spectra to evaluate their utility in solid-phase ch... Proton NMR-spectra of Wang resin bound compounds were obtained using the magic angle spinning 1HNMR technique with standard equipment. It was possible to analyse the spectra to evaluate their utility in solid-phase chernistry. A typical example was presented, which could directly monitor solid-phase reactions 展开更多
关键词 NMR Spectroscopy to Monitor Reactions in solid-phase synthesis Use of Magic Angle Spinning DCC DCM
下载PDF
Soft chemical synthesis and electrochemical properties of tin oxide-based materials as anodes for lithium ion batteries 被引量:1
20
作者 何则强 李新海 +4 位作者 熊利芝 吴显明 刘恩辉 侯朝辉 邓凌峰 《Journal of Central South University of Technology》 2004年第2期142-146,共5页
A novel soft chemical approach was developed to synthesize tin oxide-based powders. The microstructure, morphology, and electrochemical performance of the materials were investigated by X-ray diffraction, scanning ele... A novel soft chemical approach was developed to synthesize tin oxide-based powders. The microstructure, morphology, and electrochemical performance of the materials were investigated by X-ray diffraction, scanning electron microscope and electrochemical methods. The results show that the particles of tin oxide-based materials form an interconnected network structure like mesoporous material. The average size of the particles is about 200 nm. The materials deliver a charge capacity of more than 570 mA·h·g-1. And the capacity loss per cycle is about 0.15% after being cycled for 30 times. The good electrochemical performance indicates that tin oxide-based materials are promising anodes for lithium ion batteries. 展开更多
关键词 lithium ion battery tin oxide ANODE soft chemical synthesis electrochemical property
下载PDF
上一页 1 2 153 下一页 到第
使用帮助 返回顶部