20Cr2Ni4A钢经稀土渗碳和传统工艺渗碳后表层组织的观察与分析

采用ＴＥＭ微观组织观察，发现２０Ｃｒ２Ｎｉ４Ａ钢经稀土渗碳直接淬火后，渗碳层的过共析区组织是在板条马氏体为主的基体上弥散分布着细小颗粒状碳化物；而传统工艺渗碳处理后则是基体为孪晶马氏体和更细小的残留碳化物。两种工艺所形成的不同类型的基体与碳化物形成过程有关。     

稀土对莱氏体钢共晶碳化物粒化的影响

研究了稀土对莱氏体钢中共晶碳化物热处理粒化的影响，探讨了稀土元素的作用机制。结果表明：稀土细化了莱氏钢中奥氏体晶粒和共晶碳化物，使离异共晶数量增多，减少了Ｃｒ、Ｍｏ合金元素偏析，并使Ｍ７Ｃ３（Ｍ＝Ｆｅ、Ｃｒ）碳化物中孪晶等晶格缺陷增多，从而降低碳化物的稳定性，促进了共晶碳化物的粒化动力学过程，得到良好的粒化效果。     

粉末电极伏安法测定高速钢中微量碳化物

金属电极伏安法可用于钢与合金的相分析，利用萃取残渣－金属型粉末电极提高了反应区活性相的浓度，从而提高了分析微量相的灵敏度和精密度。这种方法可用于高速钢中微量碳化物（ＭＣ）相的鉴定和定量分析。     

稀土元素对60CrMnMo热轧辊用钢高温低周疲劳循环特性的影响

研究了稀土元素对热轧辊钢６０ＣｒＭｎＭｏ高温低周疲劳循环特性的影响，同时对热疲劳前后的试样硬度进行了比较，试验结果：稀土元素可明显抑制６０ＣｒＭｎＭｏ钢疲劳过程中的循环软化，并细化了回火过程中碳化物颗粒，阻碍了热循环过程中碳化物颗粒的聚焦、长大。     

铈对M2高速钢凝固组织的作用

研究了Ｃｅ对Ｍ２高速钢凝固组织的影响及其作用机制。发现Ｃｅ在高速钢中可减轻Ｗ,Ｍｏ等合金元素的偏析,使共晶碳化物量减少并细化;Ｃｅ主要偏聚在晶界共晶碳化物与奥氏体的界面上,并有部分Ｃｅ参与形成含Ｃｅ的Ｍ２Ｃ碳化物;Ｃｅ促进共晶碳化物在高温加热时的断网和团球化。     

Cu—Nd（Ce,La）—Al合金及Raney Cu—Nd（Ce,La）催化剂的XRD研究

采用ＸＲＤ表征手段对不同稀土元素不同组成的Ｃｕ－Ａｌ－Ｍ（Ｍ＝Ｎｄ，Ｃｅ和Ｌａ）合金及其碱抽提产物ＲａｎｅｙＣｕ－Ｍ催化剂的体相结构进行了表征，发现所有Ｃｕ－Ａｌ－Ｍ合金均形成有二元ＣｕＡｌ２和三元ＣｕＭＡｌ８的两种晶相，随着稀土元素含量的增中，三元Ｃｕ，ＭＡｌ８晶相逐渐增多。而且其中的Ａｌ难于ＣｕＡｌ２中的Ａｌ的抽提，ＲａｎｅｙＣｕ－Ｍ催化剂中只存在金属铜的晶相，未形成Ｃｕ－Ｍ晶相，而一随着Ａｌ     

铈,铝变质奥—贝钢中共晶体异质核心研究

Ｃｅ、Ａｌ复合变质团球状共晶体奥贝钢（简称ＡＢＮＥ钢）中的共晶体是由于Ｃ、Ｍｎ偏析，在凝固后期奥氏体枝晶间形成了渗碳体和奥氏体的伪共晶组织。通过热力学和二维点阵错配度计算，采用透射电镜和扫描电镜观察，发现ＣｅＯ２和ＣｅＡｌＯ３作为共晶体的异质核心而使共晶体球化。     

二氧化碳催化氢化──Ni、Cu间的相互作用及不同担体的影响

本文采用ＸＲＤ、ＴＰＲ、ＴＰＤ－ＭＳ、ＴＰＳＲ－ＭＳ技术研究了金属组分Ｎｉ、Ｃｕ间及不同担体（包括ＳｉＯ＿２、ＴｉＯ＿２、Ｍｇｏ和γ－Ａｌ＿２Ｏ＿３）和活性组分Ｎｉ－Ｃｕ间的相互作用及其对ＣＯ＿２催化加氢性能的影响。结果表明，这两种相互作用，不同程度地引起催化剂吸附Ｈ＿２和ＣＯ＿２能力的变化，进而影响到ＣＯ＿２加氢的反应性能。     

四元体系CsCl—PrCl3—13%HCl—H2O（25℃）和CsCl—PrCl3—42%H…

测定了四元体系ＣｓＣｌ－ＰｒＣｌ３－１３％ＨＣｌ－Ｈ２Ｏ（２５℃）和ＣｓＣｌ－ＰｒＣｌ３－４２％ＨＡｃ－Ｈ２Ｏ（３０℃）的稳定平衡态的溶液数据，绘制了相应的溶度图，两个体系的皆中有４种固相，ＣｓＣｌ，ＰｒＣｌ３．６Ｈ２Ｏ２种原始盐和ＣｓＣｌ．ＰｒＣｌ３．６Ｈ２Ｏ，３ＣｓＣｌ．ＰｒＣｌ３．７Ｈ２Ｏ２种复盐，证实了文献中对Ｍｅｙｅｒ反应１机理的解释，并对新相进行了热分析，Ｘ射线粉末衍射及偏光显微镜测定     

稀土对铸造Cr12MoV模具钢碳化物形貌及性能的影响

研究了稀土元素对铸造Ｃｒ１２ＭｏＶ模具钢碳化物形貌及性能的影响。实验结果表明，稀土地Ｍ７Ｃ３型共晶碳化物有很强的变质作用，Ｃｒ１２ＭｏＶ模具钢铸态为粗大的网状共生共晶组织，经变质处理，共晶组织细化，离异共昌数量半多；热处理后共晶碳化物粒化且均匀分布，冲击韧性得到了明显提高，耐磨性比锻造Ｃｒ１２ＭｏＶ模具钢高出１倍以上。     

Evaluation of the separation characteristics of application-specific (fatty acid methyl esters) open-tubular columns for gas chromatography

The solvation parameter model is used to characterize the separation properties of the polar stationary phases EC-Wax and PAG with a poly(ethylene oxide) backbone (substituted with propylene oxide in the case of PAG) and the cyanopropyl-substituted polysilphenylene-siloxane stationary phase BPX90 at five equally spaced temperatures between 60 and 140 degrees C. The separation characteristics of these stationary phases are compared to four PEG and two poly(cyanopropylsiloxane) stationary phases (HP-20M, HP-Innowax, SolGel-Wax, DB-WAXetr, HP-88, and SP-2340) characterized in the same way. The database of system constants for these polar stationary phases is used to provide insight into the separation mechanism for fatty acid methyl esters and to determine selectivity differences that can be expected for generically similar stationary phase types. The discussion is not structured to indicate which stationary phase should be used for a particular separation but to provide a general framework to demonstrate the relationship between the retention mechanism and stationary phase chemistry.     

Binary ionic liquid mixtures as gas chromatography stationary phases for improving the separation selectivity of alcohols and aromatic compounds

Binary mixtures of two ionic liquids (ILs), 1-butyl-3-methylimidazolium chloride (BMIM-Cl) and 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide (BMIM-NTf2), have been studied for the first time as gas chromatographic stationary phases. The two ILs differ only in the nature of the associated anion. The solvation parameter model was used to examine the change of solvation interactions with the IL stationary phase composition. The hydrogen bond basicity increased linearly as the stationary phase was enriched with the BMIM-Cl IL. The retention factor of short-chained alcohols increased by as much as 1100% when performing the separation on a column containing an IL mixture of 25% BMIM-NTf2/75% BMIM-Cl compared to that of the neat BMIM-NTf2 IL column. By tuning the composition of the IL-stationary phase, the separation selectivity and resolution factors of alcohols and aromatic compounds were improved. A reversal of elution order was observed for specific classes of analytes with enhancements in the stationary phase hydrogen bond basicity.     

Preferential solvation stabilization for hydrophobic polymeric nanoparticle fabrication

Preferential solvation of polymer molecules and strong EPD-EPA (EPD, electron pair donor; EPA, electron pair acceptor) interaction between solvent and nonsolvent molecules were found to be of great significance in the fabrication of two kinds of aromatic polyimide (AP) nanoparticles. Surfactant free yet stable AP nanoparticles were prepared using a liquid-liquid phase separation method. The stability of the AP nanoparticles can be achieved by the solvation multilayer resulting from a solvation stabilization chain in the form of nonsolvent --> solvent --> AP (a --> b denotes that component b is solvated by component a). The significance of this stabilization chain was identified by many comparative experiments using different types of molecular probes. On the other hand, the formation of AP nanoparticles was found to be governed by a nucleation process and therefore the particle size is controlled by the nucleation rate. A very high level of supersaturation can be attained under the intensive local motions induced by ultrasound, resulting in a very high nucleation rate. This effect was found to be extremely useful in the fabrication of sub-50 nm AP nanoparticles.     

N,N-dimethylformamide-induced phase separation of hexafluoroisopropanol-water mixtures

We found that addition of N,N-dimethylformamide (DMF) induces phase separation of 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP)-water mixtures. The phase diagram of a DMF-HFIP-water ternary system at 298 K showed that phase separation occurs in a closed-loop area in the water-rich mole fraction range of x(H(2)O) > ～0.4. To clarify the mechanism of DMF-induced phase separation of DMF-HFIP-water mixtures at the molecular level, small-angle neutron scattering (SANS) and (1)H and (13)C NMR measurements were conducted on the mixtures with varying DMF concentrations along a volume ratio of HFIP to water of 1?:?1 (x(S)(HFIP) = 0.147). Additionally, the solvation structure of DMF in water and HFIP-water mixtures was elucidated by molecular dynamics (MD) simulations. The SANS results revealed that the inherent heterogeneity of HFIP-water mixtures is increased with increasing DMF concentration toward the lower phase separation concentration, but decreased when the DMF concentration further increased beyond the upper phase separation one. (1)H and (13)C NMR measurements and MD simulations suggested that preferential solvation of the hydrophobic moiety of DMF by HFIP is the main driver of the phase behaviour of the DMF-HFIP-water system.     

Selective solvation effects in phase separation in aqueous mixtures

Selective solvation can be crucial in phase separation in polar binary mixtures (water–oil) with a small amount of hydrophilic ions or hydrophobic particles. They are preferentially attracted to one of the solvent components, leading to a number of intriguing effects coupled to phase separation. For example, if cations and anions interact differently with the two components, an electric double layer emerges at a liquid–liquid interface. The main aim of this paper is to show that a strongly hydrophilic (hydrophobic) solute induces precipitation of water-rich (oil-rich) domains above a critical solute density n_p outside the solvent coexistence curve.     

Effects of ion solvation on phase equilibrium and interfacial tension of liquid mixtures

We study the bulk thermodynamics and interfacial properties of electrolyte solution mixtures by accounting for electrostatic interaction, ion solvation, and inhomogeneity in the dielectric medium in the mean-field framework. Difference in the solvation energy between the cations and anions is shown to give rise to local charge separation near the interface, and a finite Galvani potential between two coexisting solutions. The ion solvation affects the phase equilibrium of the solvent mixture, depending on the dielectric constants of the solvents, reflecting the competition between the solvation energy and translation entropy of the ions. Miscibility is decreased if both solvents have low dielectric constants and is enhanced if both solvents have high dielectric constant. At the mean-field level, the ion distribution near the interface is determined by two competing effects: accumulation in the electrostatic double layer and depletion in a diffuse interface. The interfacial tension shows a nonmonotonic dependence on the salt concentration: it increases linearly with the salt concentration at higher concentrations and decreases approximately as the square root of the salt concentration for dilute solutions, reaching a minimum near 1 mM. We also find that, for a fixed cation type, the interfacial tension decreases as the size of anion increases. These results offer qualitative explanations within one unified framework for the long-known concentration and ion size effects on the interfacial tension of electrolyte solutions.     

Dynamical arrest of electron transfer in liquid crystalline solvents

We argue that electron transfer reactions in slowly relaxing solvents proceed in the nonergodic regime, making the reaction activation barrier strongly dependent on the solvent dynamics. For typical dielectric relaxation times of polar nematics, electron transfer reactions in the subnanosecond time scale fall into nonergodic regime in which nuclear solvation energies entering the activation barrier are significantly lower than their thermodynamic values. The transition from isotropic to nematic phase results in weak discontinuities of the solvation energies at the transition point and the appearance of solvation anisotropy weakening with increasing solute size. The theory is applied to analyze experimental kinetic data for the electron transfer kinetics in the isotropic phase of 5CB liquid crystalline solvent. We predict that the energy gap law of electron transfer reactions in slowly relaxing solvents is characterized by regions of fast change of the rate at points where the reaction switches between the ergodic and nonergodic regimes. The dependence of the rate on the donor-acceptor separation may also be affected in a way of producing low values for the exponential falloff parameter.     

Modification of the murakami retention model in reversed-phase high-performance liquid chromatography for micellar chromatographic separations

A retention model for micellar liquid chromatography was tested based on the data of separation of three benzodiazepins and six β-blockers. The model was obtained by analyzing changes in the microenvironment of a sorbate in transferring from the mobile to stationary phase. It can be used to describe the retention of benzodiazepins, which are neutral under the separation conditions, and the positively charged β-blockers. The calculated model coefficients are indicative of an increase in the number of 1-pentanol molecules and sodium dodecyl sulfate monomers in the microenvironment of the sorbates in transferring from the mobile to stationary phase. The solvation of the positive β-blockers by anionic surfactant monomers was higher than that of neutral benzodiazepins.     

Possibility of predicting separations in supercritical fluid chromatography with the solvation parameter model

In order to obtain a selection of optimal chromatographic columns for the separation of chlorotriazine pesticides in packed column supercritical fluid chromatography (pSFC), a multi-criteria approach is applied. For this purpose, prediction of the separations is carried out, based on quantitative structure–retention relationships, then Derringer's desirability function is proposed to determine the stationary phase that will result in the most desirable separation. The best SFC separation obtained was then optimized using a mobile phase gradient. Besides, the accuracy of the solvation parameter model as SFC retention predictive model is assessed.