Elaboration de poudres de yig par coprecipitation

This paper deals with an original method for the preparation of ferrites with the garnet structure by coprecipitation.The different transformations of the coprecipitated hydroxide during heat treatment are studied and reported.YIG crystallization from amorphous oxide is significantly dependent of some parameters.However, pure homogeneous materials can be obtained at low temperature (800–850C) for Al substituted YIG Y₃Al_xFe_5–xO₁₂ with 0.5x1.

     

新型大环醚的合成——1,7-N,N′双取代-1,7-二氮-4,10,13-三氧环十五烷的合成

我们曾报道1,10-N,N’-双取代-1,10-二氮-4,7,13,16-四氧环十八烷(1)及1,7-N,N’-双取代-1,7-二氮-4,10-二氧环十二烷(2)二类大环聚醚的合成及其对碱金属离子的络合性能。     

Bestimmung von Gleichgewichtskonstanten für Ligandenaustauschreaktionen von [TcNX4]− (X = Cl,Br) mit Hilfe der EPR

Polynuclear Complexes with Fe? As, Fe? Sb, and Fe? Bi Frameworks The anionic iron clusters Fe₃(CO)₁₁^2? and Fe₄(CO)₁₃^2? were reacted with compounds EX₃ and with organic derivatives REX₂ and R₂EX of the elements arsenic, antimony, and bismuth. Commonly redox and cluster degradation reactions were observed. The new complexes [(CO)₄Fe? AsMe₂? Fe(CO)₄]^?, [HFe₃(CO)₉(mu;₃-SbBu^t)]^?, [Fe₃(CO)₁₀ (mu;₃-Sb)]^?, and [Fe₃(CO)₁₀(mu;₃-Bi)]^? were formed and isolated as their PPN salts. The Fe? As? Fe complex was identified by a structure determination, the other complexes were identified by their spectra.     

NaAg3S2, ein Thioargentat mit dem Clusteranion [Ag6S4]2−

NaAg₃S₂, a Thioargentate Containing the Anionic Cluster [Ag₆S₄]^2? . Dark-red octahedrally shaped crystals of NaAg₃S₂ could be obtained by the reaction of NaAg(CN)₂ and NaCN in a stream of hydrogen sulfide at 630 K. NaAg₃S₂ crystallizes cubic, a=12.358(1) Å, space group Fd3 m, Z=16. The structure was determined from four-circle diffractometer data. NaAg₃S₂ contains the anionic cluster [Ag₆S₄]^2?. The structure can be traced back to the spinel structure typ. An extended Hückel calculation for the cluster anion, which is considered to be isolated, shows weak bonding silver-silver interactions. NaAg₃S₂ is diamagnetic at room temperature.     

Preparation of Layer Structure-Controlled Ru-Sn-Al2O3 Catalysts and Their Reactivity

In order to achieve functional group selective hydrogenation, the layer structure of Ru-Sn-Al2O3 catalysts was controlled by using sol-gel, powder impregnation and combined sol-gel impregnation methods. The properties of the catalysts and effectiveness in hydrogenation of dimethyl terephthalate were examined. The surface Sn contents of the catalysts characterized by X-ray photoelectron spectroscopy depended on the preparation method, in spite of almost the same bulk Ru and Sn compositions measured by X-ray fluorescence analyses. TPR and CO adsorption of the catalysts also depended on the preparation method. With regard to the conversion rate of dimethyl terephthalate and the rate of product conversion from methyl 4-hydroxy methylbenzoate to p-xylene via methyl p-toluate, Ru impregnation catalysts had higher rates than the other catalysts.     

从蓖麻油制取10-羟基癸酸的研究

本文报道了从蓖麻油制取10-羟基癸酸的研究,发现了从蓖麻油制取10-羟基癸酸的新的工艺路线和最佳的工艺条件,用氢氧化钠用量、2-辛醇量、反应时间和反应温度四因子三水平L_9(3~4)进行了正交试验,发现最佳工艺条件是:氢氧化钠(g)/蓖麻油(g):1.25:2-辛醇量(g)/蓖麻油(g):2:反应时间:6h;反应温度:180℃。在这一新的工艺路线和最佳工艺条件下,10-羟基癸酸产率可达75％。     

警惕锌剂治疗的毒性和副作用

临床实践证明某些疾病补锌治疗有效，但也发现1％左右的人出现副作用，人类对锌过量虽具有耐受性，但据报道不管是急性中毒量，治疗量，还是常用的自选补充量，均可出现中毒症状。原因是锌与其它元素间有相互作用，特别是与铜的拮抗作用，所以用锌剂一定要严格掌握适应症、剂量、疗程，以免引起不良反应，影响儿童健康。     

吲哚衍生物与花生酸混合LB膜的制备及结构研究

本文将3-三氰基乙烯基-N-十六烷基吲哚与花生酸混合制成单分子膜。不同摩尔比混合膜的π-A曲线均出现平台,表明膜压缩过程中分子排列相态发生变化。混合LB膜的紫外吸收光谱证明吲哚分子形成聚集体,X-射线衍射结果说明这种聚集体被夹带在花生酸的框架结构中。     

低硫可膨胀石墨的制备

低硫可膨胀石墨的制备宋克敏，路文义，高淑英，阎秋燕（河北教育学院石家庄０５００９１）关键词低硫可膨胀石墨，制备，过氧化氢，硫酸柔性石墨具有耐高温、耐酸碱、抗拉、抗压、抗辐射、回弹性等优良性能，被广泛应用于化工、机械、肮天、原子能等领域。但其原材料可膨...     

RExOy.nH2O对氟离子的吸附性能

La、Ce等稀土水含氧化物对阴离子的吸附性早有研究「‘－‘1，但从混合轻稀土氯化物制得的水合氧化物吸附F一的研究报道较少．为探讨难溶金属水合氧化物的除氟性能，本文以混合轻稀土氯化物为原料，制得其水含氧化物（RExOy·nH。O），采用高聚物造粒，研究了粒状RExOy·nH。O对F一的吸附性能及吸附机理．所用混合轻稀土氯化物由包头钢铁稀土公司提供，其主要组成（以氧化物计）为：CeO。（50％）、Nd。O3（25％）、La。O。（15％）、P36Oll（8％）．聚丙烯睛分子量为（2．5～5）X10‘．其它试剂为分析纯．RExO．·nH。O参照文…