凝胶体系中羧酸对草酸钙结晶的影响

羧酸是泌尿系结石形成的抑制剂。本文采用双扩散法考察凝胶体系中一元羧酸HAc、二元羧酸酒石酸、三元羧酸柠檬酸和四元羧酸EDTA对草酸钙(CaOx)结晶的影响。HAc没有抑制作用。酒石酸和柠檬酸能够改变一水草酸钙(COM)晶体的形貌，并抑制草酸钙晶体二维生长，这种抑制作用随时间的增加而增强。EDTA使COM晶体在长度方向生长更快，而在宽度和厚度上生长更慢。随着结晶温度的降低，形成草酸钙晶体的时间增加，且二水草酸钙(COD)的比例增加。在5℃的低温条件下，添加有二元、三元和四元羧酸的CaOx结晶中，COD成为主要的物相。     

络合滴定法测定钙含量微型实验研究

利用微型滴定法测定含钙制品中的Ca2 含量,并对微型滴定法与常量滴定法的平行测定结果进行了比较。结果两种方法无显著性差异,F检验t检验结果均在允许范围内,相对偏差均小于2.0%,微型滴定法的精度达到常量滴定法测定水平,能满足化学分析要求。     

Electrical conduction nature and phase transition in CaTi1−x FexO3−δ (x = 0.1–0.5)

Transport numbers for oxygen ions and protons are measured by an emf method in the system CaTi_1?x Fe_xO_3?δ (x = 0.1–0.5) in the oxidizing and reducing atmospheres in the temperature interval 973–1173 K. It is shown that the compounds under study are mixed ion-electron conductors at small iron concentrations and electron conductors, at large iron contents. The proton conductivity in the compounds is very poor and does not exceed 0.5% in air. On the basis of the temperature dependences of transport numbers for ions and linear expansion, it is established that the CaTi_0.9Fe_0.1O_3?δ system has a phase transition of a second order in a reducing environment at 1020–1050 K. The total and partial electron conductivities of CaTi_0.9Fe_0.1O_3?δ are studied as a function of the partial pressure of oxygen at 1173 K. The nature of electroconduction in CaTi_1?x Fe_xO_3?δ is discussed.     

12-钨磷酸希土盐DMF、DMSO加合物的合成、性质及其热分解动力学常数研究

合成了8种钨磷酸希土盐LnPW₁₂O₄₀·xH₂O(Ln=Y、La、Nd、Sm、Gd、Dy、Ho、Yb)的DMF、DMSO加合物,对加合物进行了组成分析,通过IR光谱、TG-DTA曲线对加合物进行了性质表征,并着重研究了加合物热分解过程的动力学,给出了热分解反应级数n和活化能E.     

掺杂Tb3+的混合碱土金属钨酸盐的合成和性质

合成了掺杂Ｔｂ（３＋）的混合碱土金属钨酸盐，测定了其发射光谱和激发光谱，用粉末Ｘ射线衍射和电子衍射法表征了其晶体结构，并对钨酸钙钡单晶体进行了Ｘ射线能谱成份分析．探讨了碱土金属钨酸盐的溶混性成因以及在这些晶体中Ｔｂ（３＋）发光和能量传递机理．     

110K铋基超导相形成的组成条件

Bi-Sr-Ca-Cu-O超导材料中存在110K和80K2个超导相。其组成是Bi_2Sr_2Ca_2Cu_3O_y和Bi_2Sr_2CaCu_2O。但迄今为止,在按2223组成比合成的未掺杂Bi系超导材料中从未得到过纯的110K相,也未见过组成为2223,零电阻温度在100K以上材料的报道。为了探索形成110K相的最佳条件,本文以2223组成比为参考,合成了5个系列材料:Bi_xSr_2Ca_2Cu_3O_y,Bi_2Sr_xCa_2Cu_3O_y,Bi_2Sr_2Ca_xCu_3O_y,Bi_2Sr_2Ca_2Cu_xO_y,Bi_i Sr_uCa_yCu_wO_s。     

BiPbSbSrCaCuO的超导电性

据报,在BiPbSrCaCuO中加Sb形成BiPbSbSrCaCuO体系的T_c可达130K。但其组成、结构、性质等均未见详细报道。我们合成了一系列BiPbSbSrCaCuO,发现了一个具有2212相结构、但T_c却为～110K的超导相。 试样制备包括将Bi_2O_3,PbO,Sb_2O_3,SrCO_3,CaO和CuO(AR级)混匀、碾磨、于     

接枝改性碳酸钙及其在聚合物中的应用研究

介绍了近年来碳酸钙表面接枝改性的研究进展,讨论了自由基接枝聚合、辐照接枝聚合和力化学表面接枝聚合及偶联剂预处理与辐照并用接枝聚合改性方法。其中重点讨论了最新研究的偶联剂预处理与辐照并用接枝改性纳米碳酸钙的方法。用此方法制备的聚合物/纳米碳酸钙纳米复合材料在其他力学性能基本不变的情况下,大幅度提高了其缺口冲击强度和断裂伸长率。指出了碳酸钙表面接枝改性应向着提高接枝单体量和采用弹性体单体方面发展。     

废弃生物质在超临界水中转化制氢过程的研究

以废弃生物质转化为富氢气体为目的，使用间歇式超临界水反应器，在反应温度773 K～923 K、压力15.5 MPa～34.5 MPa停留时间1 min～30 min和Ca/C摩尔比0～0.56范围内，对木屑在超临界水条件下生成的气体组成及产率进行了考察。实验表明，Ca/C摩尔比和温度对木屑转化的影响较大。当Ca/C摩尔比为0.48时，碳的气体转化率和氢气产率提高了近一倍。温度从773 K提高到923 K，碳的气体转化率由47％提高到76％，氢气产率由4.5 mmol/g上升到6.9 mmol/g。与温度相比，停留时间和压力的影响不大。     

Cobalt(II) Chloride Complex Formation in Acetamide–Calcium Nitrate Tetrahydrate Melts

The absorption spectra of Co(II) chloride complexes, containing variable concentrations of chloride ligand, in a molten mixture of 80 mol% acetamide–20 mol% calcium nitrate tetrahydrate, were studied at 313, 333, 353, and 363 K, in the wavelength range 400-800 nm. The melt contains three possible ligands (CH₃CONH₂, H₂O, and NO₃ ^-) for competition with added chloride ligand. Addition of chloride caused a shift of the absorption maximum of octahedral cobalt(II) nitrate towards lower energies and pronounced changes in the shape of the initial spectrum of cobalt(II) nitrate. The effect of temperature changes on the molar absorption coefficient of the Co(II) species was dependent on the chloride concentration and was attributed to the structural changes occurring in the cobalt(II) species. The STAR and STAR FA programs were applied to identify the complex ionic species and to calculate the stability constants of Co(II) complexes formed in this solvent. The results indicate the highest probability of formation of the following complex species: Co(NO₃)₄ ^2-, Co(NO₃)₂Cl₂ ^2-, and CoCl₄ ^2-. Stability constants of each complex were presented for the equilibria occurring at 313, 333, 353, and 363 K. Distribution of the Co(II) species was also calculated over the ranges of chloride concentration and temperature investigated.