过硼酸钠结晶介稳区的测定

采用激光测定装置测定了过硼酸钠的溶解度和超溶解度,重点研究了过硼酸钠的溶解度、超溶解度以及结晶介稳区的变化规律,获得了过硼酸钠溶液的结晶介稳区,并用Apelblat方程对过硼酸钠的溶解度数据进行了关联。 研究了降温速率、搅拌速率、六偏磷酸钠及聚丙烯酸钠添加量对过硼酸钠介稳区宽度的影响规律。 研究结果表明,过硼酸钠溶解度随温度升高而增大,过硼酸钠的介稳区宽度在高温区较小而在低温区较大;降温速率的增大使过硼酸钠介稳区宽度变大,搅拌速率的增大使介稳区宽度变小;加入0.065%六偏磷酸钠和0.045%聚丙烯酸钠时获得的介稳区宽度最大。     

不同浓度KCl和NH4Cl溶液中H3BO3介稳区的性质

测定了H3BO3在0~25 ℃内于不同浓度KCl和NH4Cl溶液中的溶解度和超溶解度, 得到了H3BO3的介稳区宽度, 并推算出表观成核级数m, 给出了成核速率方程. 研究了KCl和NH4Cl对H3BO3介稳区性质的影响, 并对影响的机理进行了探讨. 结果表明, KCl使H3BO3介稳区向低温方向移动; NH4Cl使H3BO3介稳区向高温方向移动; 根据所得结论分析了KCl和NH4Cl在柴达木西部油田水析硼过程中的影响, 认为KCl和NH4Cl在蒸发过程中浓度的变化是造成硼分散析出而不能富集的因素之一.     

钴胺素溶析结晶过程及离子杂质对其晶体生长的影响

采用激光法研究了钴胺素的结晶过程热力学,考察了温度、溶剂对溶解度和超溶解度的影响,并测定了介稳区,介稳区的宽度随体系中丙酮含量的减小而变宽. 研究了离子杂质Na+、Mg2+、Ca2+和Fe3+对钴胺素结晶诱导期的影响. 结果表明,离子的存在使得晶体更容易出现断裂和聚结,并用扫描电子显微镜测试技术对晶体的表面形貌进行了表征. 结果表明,Fe3+、Mg2+比Na+、Ca2+影响更明显.     

溶剂甲醇过程的溶剂选择

溶剂甲醇过程的溶剂选择至关重要。本文筛选了三乙二醇二甲醚（ＴＲＩＧＬＹＭＥ）作为溶剂，测定了甲醇在溶剂中的溶解度及活度系数。在本文的研究条件下，甲醇的溶解特性符合亨利定律，以实验数据回归，亨利系数Ｈ＝０．３７４３ｅｘｐ（－３０１３．６／Ｔ）ＭＰａｍ＾３ｍｏｌ＾－１。通过与其他溶剂比较后可以得出：按甲醇在不同溶剂中的溶解度大小排序：ＴＧＩＧＬＹＭＥ〉ＴＥＧＤＭＥ〉Ｓｑｕａｌａｎｅ〉ＶｅｓｔｏｗａｘＳ     

NaCl、KCl在CH_3OH+DMF或DMSO混合溶剂中的溶解度,278、288、298、303、313K

本工作测定了NaCl、KCl在CH_3OH与DMF及CH_3OH与DMSO全组成范围混合溶剂中的溶解度。实验温度分别是;对NaCl:278、288、298、303、313K,对KCl:288、303、313K。随着溶剂组成变化KCl和NaCl的溶解度曲线皆有一极大值。溶解度温度系数分别为正和负,随着溶剂中CH_3OH组份的减少温度系数减小。根据实验结果,计算得NaCl和KCl自甲醇至混合溶剂的转移自由能和熵。对离子在此混合物中的溶剂化、结构影响和盐的溶解倾向作了初步解释。     

NaCl、KCl在CH3OH+DMF或DMSO混合溶剂中的溶解度, 278、288、298、303、313 K

本工作测定了NaCl、KCl在CH_3OH与DMF及CH_3OH与DMSO全组成范围混合溶剂中的溶解度。实验温度分别是; 对NaCl:278、288、298、303、313 K, 对KCl:288、303、313 K。随着溶剂组成变化KCl和NaCl的溶解度曲线皆有一极大值。溶解度温度系数分别为正和负, 随着溶剂中CH_3OH组份的减少温度系数减小。根据实验结果, 计算得NaCl和KCl自甲醇至混合溶剂的转移自由能和熵。对离子在此混合物中的溶剂化、结构影响和盐的溶解倾向作了初步解释。     

测定溶解度组装阴离子手性离子液体的研究

本文利用无机盐和有机盐在有机溶剂中的溶解度的差异,设计组装手性羧酸阴离子离子液体.测定氯化钠、氯化钾、溴化钠和溴化钾和手性有机羧酸盐((R)-2-羟基-4-苯丁酸钠或钾)在甲醇、乙醇或丙酮中的溶解度,一定温度下计算溶解度比值,理论推测该条件下阴离子交换比例.研究发现,当无机盐与有机盐的溶解度比值小于0.05时,阴离子交...     

钴胺素的溶析结晶研究以及离子杂质对晶体生长的影响

采用激光法研究了钴胺素的结晶热力学,包括在不同温度下,不同溶剂配比下的溶解度和超溶解度,介稳区的测定。研究了四种不同的离子杂质(Na+,Mg2+,Ca2+and Fe3+)对钴胺素结晶诱导期的影响。通过实验结果表明钴胺素在溶析结晶过程中,Fe3+和Mg2+要比Na+和Ca2+具有更明显的影响。     

Li~ ,Na~ //SO_4~(2-),B_4O_7~(2-)-H_2O交互四元体系288K介稳相平衡研究

采用等温蒸发法研究了四元体系Li ,Na //SO42-,B4O72--H2O288K介稳相平衡及平衡液相物化性质(密度、电导率、折光率、粘度和pH值),测定了该四元体系288K条件下介稳平衡溶液溶解度及物化性质。根据实验数据绘制了相应的介稳相图及物化性质组成图。研究发现:该体系介稳平衡中有复盐Li2SO·4Na2SO4形成。其介稳相图中有3个共饱和点,7条单变量曲线,平衡固相为:Li2SO·4H2O,Na2SO4,Li2SO·4Na2SO4,Li2B4O7·3H2O,Na2B4O·710H2O。复盐Li2SO·4Na2SO4和一水硫酸锂(Li2SO·4H2O)有较小的结晶区,而Li2B4O7·3H2O和Na2B4O7·10H2O有较大的结晶区;该四元体系介稳平衡条件下未发现Na2SO·410H2O的结晶区。     

五元体系Li~+,K~+//CO_3~(2-),SO_4~(2-),B_4O_7~(2-) -H_2O在288 K时的介稳相平衡研究

采用等温蒸发法研究了五元体系Li~+,K~+//CO_3~(2-),SO_4~(2-),B_4O_7~(2-) -H_2O在288 K时的介稳相平衡关系,测定了该五元体系在288 K条件下的介稳平衡的溶解度和溶液密度,根据实验数据绘制了相应的介稳平衡相图和水图,相平衡研究结果表明该五元体系介稳相平衡中有复盐K_2SO_4·Li_2SO_4生成,其介稳相图(Li_2CO_3饱和)有4个共饱和点,9条单变量曲线,6个Li_2CO_3饱和的结晶区分别为LiBO_2·8H_2O,K_28_4O_7·4H_2O,K_2CO_3·3/2H_2O,K_2SO_4,Li_2SO_4·H_2O和复盐K_2SO_4·Li_2SO_4.     

Novel Phenomena of Crystallization and Emulsification of Hydrophobic Solute in Aqueous Solution

Emulsification of lauric acid in an aqueous ethanol solution including lauric acid solute has been observed during cooling before crystallization of lauric acid occurs. The nature of two different solubility curves was explained for the system of lauric acid and aqueous ethanol solution. The mutual solubility of the two liquid phases controls emulsification; the solid solubility of lauric acid controls crystallization. The mutual solubility curve appears at relatively high temperature, and the solid solubility curve at relatively low temperature. Crystallization essentially generates a solid metastable zone under the solid solubility curve. A supersaturated solution can be obtained in the metastable zone. However, no nucleation occurs in the metastable zone. The metastable zone, therefore, still caused emulsification at low temperature before crystallization of lauric acid occurred. The hypothetical mutual solubility curve for the aqueous solution including hydrophobic solutes appeared invariably even at low temperature in the metastable zone under the solid solubility. Copyright 2001 Academic Press.     

硫酸钾水溶液亚稳区性质的研究(Ⅳ)——杂质Li+对结晶过程的影响

本文根据实际生产的需要,详细地研究了杂质Li⁺对K₂SO₄结晶过程的影响,并结合理论分析。计算了杂质Li⁺对K₂SO₄结晶过程中成核特征的影响.结果表明,Li⁺改变了体系的比表面自由能δ₁₂、成核势垒△G(r^*),使亚稳区宽度增加.     

Effects of different temperatures and additives on the metastable zone width precipitation kinetics of NaBO2

In this study, the sodium metaborate, which is applicable in various industrial areas, and its metastable zone width that is very important for its production by crystallization, and its nucleation are investigated to obtain the necessary thermodynamic parameters. The polythermal and isothermal method has been used for the measurement of metastable zone width. Metastable zone width of NaBO₂ has found at 9°C at average and cooling rate do not have any effect on it. In addition, the effect of sodium metaborate on the hydrogen storage capacity of sodium borohyride solutions that is known as one of the best hydrogen sources today is investigated at the various concentrations of sodium borohyride in the medium. Results have shown that three different areas emerged as the percentage of NaBH4 in the solution increased.     

杀虫单介稳区宽度的理论计算

从晶体生长成核、动力学等几个方面出发,在Mersmann模型基础上建立了适合高粘度有机体系的介稳区宽度的理论计算模型,确立了计算程序和方法.结合“杀虫单”农药结晶过程的具体参数,计算和预测了工业结晶过程中介稳区的宽度.理论计算值与实验测定值较为接近.该方法可为工业结晶中过饱和度的选择提供参考.     

Phase Relations in Metastable Equilibria of the PbO-GeO2 System

Metastable phase relations in the PbO-GeO₂ system have been studied by DTA and X-ray powder diffraction. Metastable equilibrium was acquired during the solidification of a melt while it was slowly (at 8 K/min) cooled from temperatures slightly exceeding the critical value for a given composition. In the metastable equilibrium acquired in this way, α-PbO-base solid solution and four metastable individual phases were observed in the system at room temperature, with different structures and different thermal stabilities. A metastable equilibrium phase diagram has been mapped.     

Kinetic energy release in ionic fragmentations: Use as an ion structure probe

The kinetic energy released in unimolecular reactions, as measured from the width of the corresponding metastable peak, shows only a small dependence on such parameters as source temperature, ion-source residence time and ion acceleration voltage. Similarly, fragmenting ions generated from different members of an homologous series of molecular ions have been found to release the same kinetic energy and hence do not exhibit a degrees-of-freedom effect analogous to that for metastable abundances. In general, molecular ions formed by electron-impact have been found to release slightly less kinetic energy on fragmentation than the corresponding ions formed via a fragmentation sequence. These observations suggest that kinetic energy release is a useful method of structural characterization of metastable ions; while increase in the average internal energies of the ions sample lead to larger energy releases, this effect is usually small. The use of a very narrow energy resolving (β) slit and a procedure in which the metastable peak width is extrapolated to zero slit width has been found to improve the accuracy of measurement of the kinetic energy release, particularly when the metastable and main beam peak widths are of comparable magnitude.     

Replica theory of the rigidity of structural glasses

We present a first principle scheme to compute the rigidity, i.e., the shear-modulus of structural glasses at finite temperatures using the cloned liquid theory, which combines the replica theory and the liquid theory. With the aid of the replica method which enables disentanglement of thermal fluctuations in liquids into intra-state and inter-state fluctuations, we extract the rigidity of metastable amorphous solid states in the supercooled liquid and glass phases. The result can be understood intuitively without replicas. As a test case, we apply the scheme to the supercooled and glassy state of a binary mixture of soft-spheres. The result compares well with the shear-modulus obtained by a previous molecular dynamic simulation. The rigidity of metastable states is significantly reduced with respect to the instantaneous rigidity, namely, the Born term, due to non-affine responses caused by displacements of particles inside cages at all temperatures down to T = 0. It becomes nearly independent of temperature below the Kauzmann temperature T(K). At higher temperatures in the supercooled liquid state, the non-affine correction to the rigidity becomes stronger suggesting melting of the metastable solid state. Inter-state part of the static response implies jerky, intermittent stress-strain curves with static analogue of yielding at mesoscopic scales.