热声系统中回热器特征阻抗与传播常数的研究

针对本实验室一台声驱动热声系统,采用传递函数法研究声驱动系统中回热器的特征阻抗和传播常数.通过调节谐振管长度,改变回热器表面的阻抗,从理论上分析了回热器网络传输方程中的声传播常数、特征阻抗与系统网络元件中的阻抗、导纳和流的关系.并且进一步讨论有无换热器以及不同的加热功率对回热器网络参数的影响.结论有利于进一步量化回热器的网络参数.     

紫外差光谱测定Gd(Ⅲ), Yb(Ⅲ)与HBED配合物的条件稳定常数

在0.01 mol·L-1 N-2-羟乙基哌嗪-N'-2-乙磺酸(Hepes), pH 7.4, 室温条件下, 应用紫外差光谱滴定观察了Gd(Ⅲ), Yb(Ⅲ)与N, N'-二(2-羟苄基)乙二胺-N, N'-二乙酸(HBED)的结合. 结果表明 Gd(Ⅲ), Yb(Ⅲ)与HBED均形成1∶1的配合物, 其紫外差光谱均于237和291 nm处出现吸收峰, 在237 nm处配合物Gd-HBED与Yb-HBED的摩尔吸光系数分别为 ΔεGd=(22.52±0.20)×103 cm-1·mol-1·L, ΔεYb=(27.15±0.11)×103 cm-1·mol-1·L; 配合物Gd-HBED与Yb-HBED的条件稳定常数分别为 lgKGd-HBED=13.56±0.28, lgKYb-HBED=16.06±0.03, 符合线性自由能关系.     

用电子分析天平测量静电力及真空介电常量

介绍了用电子分析天平测量平行板电容器两极板间的静电力和真空介电常量的原理和方法．     

修饰聚合物液-固亲和萃取体系分离钪与钕及机理探讨

研究了加修饰聚合物(PEG-IDA)的吐温(Tween)80-盐水液-固体系亲和萃取稀土(RE)离子时体系酸度对萃取率的影响,并控制萃取酸度实现了Sc与Nd的定量分离,平均回收率Sc：99．72％;Nd：100.88％。测定新络合物的稳定常数,两者相差4倍,是分离的原因。对该体系分离Sc与Nd的机理进行探讨表明,RE-PEG-IDA络合物主要是与Tween 80形成了氢键。     

硒功能化杯芳烃载体银离子选择性膜电极的研究

合成6个硒功能化杯芳烃为载体,采用双层夹心膜电位法直接测定了溶剂聚合物膜中载体与金属离子生成的络合物生成常数。制备并考察了以硒功能化杯芳烃为载体的银离子选择性电极的性能,发现以载体6为银离子选择性电子的载体,制成的膜电极,用作Ag^ 电位滴定Cl^-的指示电极,效果最佳。     

分段常数变元的中立型方程的振动性

给出了一类含连续和分段常数变元的中立型方程振动的两个充分条件,改进和推广了已知文献中的一些结果.     

水溶液中亚甲蓝分子聚集状态的研究

用分光光度法研究了亚甲蓝(MB)染料在水溶液中的聚集状态及其与表面活性剂的相互作用,讨论了无机盐对亚甲蓝在阴离子表面活性剂溶液中聚集状态的影响。推导了水溶液中亚甲蓝单体和二聚体的动态平衡关系式。利用计算机程序不仅求出了与作图法结果非常接近的MB单体的摩尔吸光系数和聚合平衡常数,而且求出了MB二聚体的摩尔吸光系数及相应浓度下MB单体所占的比例系数。     

异双核X-M之间的磁耦合交换作用: Keggin型杂多酸衍生物[M(H2O)XW11O39]7-(X=FeⅢ, CoⅢ; M=CoⅡ)的密度泛函研究

采用DFT-BS方法研究异双核的Keggin型杂多酸衍生物[M(H2O)XW11O39]7-(Ⅰ: X=FeⅢ, M=CoⅡ; Ⅱ: X=CoⅢ, M=CoⅡ)的磁耦合作用, 计算得到耦合常数(J)为负值, 表明所研究体系具有反铁磁性; J值大小顺序为|J(Ⅰ)|<|J(Ⅱ)|, 说明磁耦合作用增强; 体系Ⅰ与Ⅱ相比, X由FeⅢ变成CoⅢ, M不变, 桥氧原子Ob和Ob2(O′b2)上的自旋密度增大, 进一步从相关BS态的磁轨道比较得出, 体系Ⅱ中轨道重叠程度大于体系Ⅰ, 结果使X-M之间的反铁磁耦合作用加强.     

Density-and-temperature-dependent volume translation for the SRK EOS: 1. Pure fluids

A mathematical framework for applying a density-and-temperature-dependent volume translation in a thermodynamically consistent manner was developed. Volumetric equations of state (EOS)s that incorporate this translation procedure can be used to generate derived properties, such as fugacity and enthalpy departure, that are based on isothermal departure or residuals from ideal gas state conditions. This kind of translation serves to improve the original EOS and not simply act as a correlation for molar volumes. A density-and-temperature-modified translation of this type was applied to the Soave–Redlich–Kwong EOS and was shown to possess accuracy for saturation pressure predictions equivalent to the untranslated EOS, as well as greatly improved density predictions compared to what is available when using only constant valued translation. The EOS translated in this manner retains many of the important features of the untranslated EOS, such as explicit calculation of volume roots, while having the representation capabilities of substantially more complicated models, such as the extended virial equation of Benedict, Webb, Rubin, and Starling.     

Thermodynamic determination of solvation potentials of various metal chlorides by (1,4-dioxane + water) mixtures through EMF measurements

The EMF data of different metal chlorides (2:1 electrolytes) were obtained by using a cell [M_X Hg|MCl₂ (m)|AgCl–Ag] at two temperatures. Stock solutions of metal chlorides (CoCl₂, CuCl₂ and ZnCl₂) were prepared by weight in 1,4-dioxane–aqueous mixtures. There was a significant change in the EMF values with change of metal chloride, its concentration and solvents composition. The standard electrode potential (E°) values of the above cell were calculated from the measured EMF of these mixtures. The standard thermodynamic functions (ΔG°, ΔH° and ΔS°) and respective transfer parameters of MCl₂ from water to 20, 45 and 70% dioxane–water mixtures were also evaluated. Equilibrium dissociation constants (K₁ and K₂) as well as the degrees of dissociation (α₁ and α₂) were obtained by iterative procedures. The data were analyzed in terms of solute–solvent interactions depending on standard and transfer thermodynamic parameters and mean activity coefficients (γ_±) of electrolytes.