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A Review of Chitin Solvents and Their Dissolution Mechanisms 被引量:6
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作者 Yi Zhong Jie Cai LiNa Zhang 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2020年第10期1047-1060,I0004,共15页
Chitin is an abundant natural nitrogen-containing biopolymer with great application potential in materials,environment,energy,and health.However,the structure characteristics and processing technologies have required ... Chitin is an abundant natural nitrogen-containing biopolymer with great application potential in materials,environment,energy,and health.However,the structure characteristics and processing technologies have required intense research in related applications.In particular,there have been great efforts to developing solvents for chitin,and the results s0 far are quite encouraging.This review summarizes the main solvent systems used for chitin,namely the aqueous solvent systems(mineral acids,inorganic salt aqueous solutions,alkali aqueous solutions)and non aqueous ones(LiCl-dimethylacetamide solvents,CaCl22H2O saturated methanol,ionic liquids,deep eutectic solvents,and protic organic solvents).The solvent properties,dissolution methods,and solution properties are discussed in detail.Special attention is paid to the dissolution mechanism in each system.This review can provide a reference for understanding the dissolution behavior of chitin and finding suitable solvents for it. 展开更多
关键词 CHITIN Solvents dissolution mechanism Hydrogen bonding
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Dissolution mechanism of a deep-buried sandstone reservoir in a deep water area:A case study from Baiyun Sag,Zhujiang River(Pearl River)Mouth Basin 被引量:1
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作者 Jihua Liao Keqiang Wu +3 位作者 Lianqiao Xiong Jingzhou Zhao Xin Li Chunyu Zhang 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2023年第3期151-166,共16页
Dissolution mechanism and favorable reservoir distribution prediction are the key problems restricting oil and gas exploration in deep-buried layers.In this paper,the Enping Formation and Zhuhai Formation in Baiyun Sa... Dissolution mechanism and favorable reservoir distribution prediction are the key problems restricting oil and gas exploration in deep-buried layers.In this paper,the Enping Formation and Zhuhai Formation in Baiyun Sag of South China Sea was taken as a target.Based on the thin section,scanning electron microscopy,X-ray diffraction,porosity/permeability measurement,and mercury injection,influencing factors of dissolution were examined,and a dissolution model was established.Further,high-quality reservoirs were predicted temporally and spatially.The results show that dissolved pores constituted the main space of the Paleogene sandstone reservoir.Dissolution primarily occurred in the coarse-and medium-grained sandstones in the subaerial and subaqueous distributary channels,while dissolution was limited in fine-grained sandstones and inequigranular sandstones.The main dissolved minerals were feldspar,tuffaceous matrix,and diagenetic cement.Kaolinization of feldspar and illitization of kaolinite are the main dissolution pathways,but they occur at various depths and temperatures with different geothermal gradients.Dissolution is controlled by four factors,in terms of depositional facies,source rock evolution,overpressure,and fault activities,which co-acted at the period of 23.8–13.8 Ma,and resulted into strong dissolution.Additionally,based on these factors,high-quality reservoirs of the Enping and Zhuhai formations are predicted in the northern slope,southwestern step zone,and Liuhua uplift in the Baiyun Sag. 展开更多
关键词 dissolution mechanism deep-buried reservoir diagenesis evolution reservoir prediction deep water region Baiyun Sag
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Effects of copper ions on dissolution mechanism of marmatite 被引量:2
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作者 Xiao-yu MENG Hong-bo ZHAO +3 位作者 Yi-sheng ZHANG Shuai WANG Guo-hua GU Guan-zhou QIU 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2022年第12期4099-4112,共14页
The dissolution mechanism of marmatite in the presence of Cu^(2+)was intensively studied by experiments and density functional theory(DFT) calculations. Leaching experiments showed that Cu^(2+)accelerated marmatite di... The dissolution mechanism of marmatite in the presence of Cu^(2+)was intensively studied by experiments and density functional theory(DFT) calculations. Leaching experiments showed that Cu^(2+)accelerated marmatite dissolution at high temperatures(above 55 ℃), but the trend was reversed at low temperatures(below 45 ℃), which may be because the reaction mechanism between Cu^(2+)and marmatite changed from surface adsorption to bulk substitution with increasing temperature. The substitution reaction caused more zinc atoms in the marmatite crystal lattice to be released and enhanced the electrochemical reactivity, while the adsorption of copper ions at low temperatures would passivate marmatite, thus inhibiting the reaction process. DFT calculations showed that the energy of the substitution reaction was more negative than that of the adsorption reaction at high temperatures, which further verified the proposed mechanism. 展开更多
关键词 dissolution mechanism SPHALERITE MARMATITE copper ion
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Dissolution mechanism and solubility of hemimorphite in NH_3-(NH_4)_2SO_4-H_2O system at 298.15 K
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作者 李琴香 陈启元 胡慧萍 《Journal of Central South University》 SCIE EI CAS 2014年第3期884-890,共7页
The dissolution mechanism of hemimorphite in NH3-(NH4)2SO4-H2O system at 298.15 K was investigated by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy ... The dissolution mechanism of hemimorphite in NH3-(NH4)2SO4-H2O system at 298.15 K was investigated by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis. The results show that hemimorphite is soluble in NH3-(NH4)2SO4-H2O system and its residue exists in the form of an amorphous SiO2 layer on the hemimorphite surface. The XPS data also indicate that the Si 2p3/2 and O ls spectra of the hemimorphite are broadened and shift to higher binding energies and their binding energies are closer to silica with an increase of total ammonia and time. Solubility of hemimorphite in NH3-(NH4)2SO4-H2O system was measured by means of isothermal solution method at 298.15 K based on the study of the dissolution mechanism of hemimorphite. The results show that the solubility of zinc in solution increases firstly and then decreases with the increase of cr(NH3) (total ammonia concentration) at different NH3/NH4^+ ratios. The solubility of silicon in solution decreases from 0.0334 mol/kg in ct(NH3)-4.1245 mol/kg NH3-(NH4)2SO4-H2O solution to 0.0046 mol/kg in cT(NH3)=7.6035 mol/kg NH3-(NH4)2SO4-H2O solution. 展开更多
关键词 HEMIMORPHITE ammoniacal solution dissolution mechanism SOLUBILITY
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Carbide Dissolution during Intercritical Austenitization in Bearing Steel
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作者 李辉 米振莉 +2 位作者 ZHANG Xiaolei TANG Di WANG Yide 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2014年第6期1242-1245,共4页
In order to investigate the carbide dissolution mechanism of high carbon-chromium bearing steel during the intercritical austenitization, the database of TCFE7 of Thermo-calc and MOBFE of DICTRA software were used to ... In order to investigate the carbide dissolution mechanism of high carbon-chromium bearing steel during the intercritical austenitization, the database of TCFE7 of Thermo-calc and MOBFE of DICTRA software were used to calculate the elements diffusion kinetic and the evolution law of volume fraction of carbide. DIL805 A dilatometer was used to simulate the intercritical heat treatment. The microstructure was observed by scanning electron microscopy(SEM), and the micro-hardness was tested. The experimental results indicate that the dissolution of carbide is composed of two stages: initial austenite growth governed by carbon diffusion which sharply moves up the micro-hardness of quenched martensite, and subsequent growth controlled by diffusion of Cr elements in M3 C. The volume fraction of M3 C decreases with the increasing holding time, and the metallographic analysis shows a great agreement with values calculated by software. 展开更多
关键词 intercritical austenitization carbide dissolution bearing steel diffusion mechanism
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Mechanism of gold dissolving in alkaline thiourea solution 被引量:1
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作者 柴立元 王云燕 《Journal of Central South University of Technology》 EI 2007年第4期485-489,共5页
Reaction mechanism of gold dissolving in alkaline thiourea solution was studied by electrochemical methods, such as cyclic voltammetry, chronopotentiometry, AC impedance, linear sweep voltammetry. Apparent activation ... Reaction mechanism of gold dissolving in alkaline thiourea solution was studied by electrochemical methods, such as cyclic voltammetry, chronopotentiometry, AC impedance, linear sweep voltammetry. Apparent activation energy of anodic process of gold electrode dissolving in alkaline thiourea solution is 14.91 kJ/moh Rate determining step is the process of gold thiourea complex diffusing away from electrode surface to solution. The results of AC impedance and chronopotentiometry indicate that thiourea adsorbs on gold electrode surface before dissolving in solution. There does not exist proceeding chemical reactions. Formamidine disulfide, the decomposed product of thiourea, does not participate the process of gold dissolution and thiourea complex. Species with electro-activity produced in the process of electrode reaction adsorbs on the electrode surface. In alkaline thiourea solution, gold dissolving mechanism undergoes the following courses: adsorption of thiourea on electrode surface; charge transfer from gold atom to thiourea molecule; Au[SC(NH2)2]ads^+ receiving a thiourea molecule and forming stable Au[SC(NH2)2]2^+; and then Au[SC(NH2)2]2^+ diffusing away from the electrode surface to solution, the last step is the rate-determining one. 展开更多
关键词 GOLD alkaline thiourea dissolution mechanism
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Characterization and mechanism of dissolution behavior of Al_(2)O_(3)/MgO oxides in molten slags 被引量:3
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作者 Yan-zhu Huo Hua-zhi Gu +4 位作者 Ao Huang Bei-yue Ma Liu-gang Chen Guang-qiang Li Ya-wei Li 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2022年第11期1711-1722,共12页
Al_(2)O_(3)-and MgO-based oxides are among the most common oxides in the steelmaking industry.They exist as the main components of refractories,inclusions,or slags.Al_(2)O_(3)-and MgO-based oxides interact with molten... Al_(2)O_(3)-and MgO-based oxides are among the most common oxides in the steelmaking industry.They exist as the main components of refractories,inclusions,or slags.Al_(2)O_(3)-and MgO-based oxides interact with molten slags continuously during the steel smelting process,which may lead to the dissolution and absorption of the oxides by molten slags,or reactions between oxides and molten slags to form intermediate products.Understanding the dissolution behavior of Al_(2)O_(3)-and MgO-based oxides in molten slags is important for prolonging the service life of refractories and removing inclusions in molten steel.Therefore,Al_(2)O_(3)-and MgO-based oxides are considered,and the test methods,dissolution mechanisms,and influencing factors are comprehensively introduced,which can provide a foundation for refractories wear and high-quality steel smelting. 展开更多
关键词 Al_(2)O_(3)/MgO oxide Slag corrosion Refractory wear INCLUSION dissolution mechanism
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Understanding cellulose dissolution: effect of the cation and anion structure of ionic liquids on the solubility of cellulose 被引量:3
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作者 Jinming Zhang Lili Xu +4 位作者 Jian Yu Jin Wu Xiaoyu Zhang Jiasong He Jun Zhang 《Science China Chemistry》 SCIE EI CAS CSCD 2016年第11期1421-1429,共9页
The effect of ionic liquids(ILs) on the solubility of cellulose was investigated by changing their anions and cations. The structural variation included 11 kinds of cations in combination with 4 kinds of anions. The i... The effect of ionic liquids(ILs) on the solubility of cellulose was investigated by changing their anions and cations. The structural variation included 11 kinds of cations in combination with 4 kinds of anions. The interaction between the IL and cellobiose, the repeating unit of cellulose, was clarified through nuclear magnetic resonance(NMR) spectroscopy. The reason for different dissolving capabilities of various ILs was revealed. The hydrogen bonding interaction between the IL and hydroxyl was the major force for cellulose dissolution. Both the anion and cation in the IL formed hydrogen bonds with cellulose. Anions associated with hydrogen atoms of hydroxyls, and cations favored the formation of hydrogen bonds with oxygen atoms of hydroxyls by utilizing activated protons in imidazolium ring. Weakening of either the hydrogen bonding interaction between the anion and cellulose, or that between the cation and cellulose, or both, decreases the capability of ILs to dissolve cellulose. 展开更多
关键词 cellulose ionic liquids dissolution mechanism cellobiose
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