(Nd1-xYx)3Fe27.31Ti1.69化合物的结构与磁性研究

制备了(Nd1-xYx)3Fe27.31Ti1.69(0≤x≤0.6)系列化合物,通过X射线衍射和磁性测量等手段研究了它们的结构和磁性.这些化合物均为Nd3(Fe,Ti)29型结构,A2/m空间群.化合物晶胞体积随Y含量增加而单调减少,居里温度Tc随Y含量增加略有降低,说明化合物的居里温度主要由Fe-Fe之间的交换相互作用所决定.温度为5K时,饱和磁化强度Ms随Y含量的增加而单调降低,与一个简单的稀释模型预期结果一致.所得化合物在低温下均发生自旋重取向,自旋重取向温度Tsr随Y含量增加而单调降低,从x=0时的232K减小到x=0.6时的121K.基于磁晶各向异性的研究结果确定了所得化合物的自旋相图.     

酞菁,酞菁铁及酞菁镍电子性质的理论研究

以双片层分子为晶体单胞模型，用量子化学具有晶体轨道的ＥＨＭＯ方法研究了酞菁、酞菁铁及酞菁镍的导电性能，讨论了碘掺杂对它的影响。计算结果表明：由于碘掺杂后，系体构型发生了较大的变化，层间作用加强，从而前述几种晶体的能隙均显著降低，电导率大幅度提高。     

THE EFFECT AND FUNCTION OF AliBu_2OR'''' ON BUTADIENE-PROPYLENE ALTERNATING COPOLYMERIZATION CATALYZED BY VO(OR)_2Cl-AIiBu_3 SYSTEM

Four kinds of AliBu_2OB' with different R' were synthesized. The effect of AliBu_2OR'/AliBu_3 mole ratio on the conversion, the [η] of copolymer and catalytic efficiency were studied. The conversion was increased obviously and the catalytic efficiency was 2.7 times higher than before. The effect of the amount of AliBu_2OR' on the valence state of vanadium ion and the change of the valence state of vanadium ion with reaction temperature and time were studied. The VIS and IR spectra of the trinary-component catalyst system were measured. The model of active center including AliBu_2OR' was proposed. The function of AliBu_2OB was explained.     

壳聚糖修饰玻碳电极卷积伏安法测定环境水中的EDTA

制备了壳聚糖修饰玻碳电极 ,研究了Fe(EDTA) -在修饰电极上的吸附还原行为 ,用卷积伏安法通过Fe(EDTA) -的检测测定了环境水中的EDTA。在优化的实验条件下 ,峰电流值与 8.0× 1 0 -7～ 5 .0× 1 0 -6mol L的EDTA呈线性关系 ,回归方程为epp′ =0 .75 2 5c - 0 .661 3,r =0 .991 ,最低检出限为 5 .0× 1 0 -7mol L ,5次测定的相对标准偏差小于 5 .8%。对实际样品测定的回收率为98 1 %～ 1 0 5 % ,对比HPLC的结果 ,相对偏差小于 5 %。     

压力、温度和晶粒尺寸对Fe-N合金的合成及结构的影响

在 1× 1 0 - 3 Pa～ 4 GPa的压力和 5 80～ 930 K温度范围内 ,利用高压技术并结合机械球磨 ,研究了压力、温度和晶粒尺寸对α-Fe与非晶 BN的固态反应的影响 .发现高压和晶粒细化可以极大地促进α-Fe和非晶 BN的固态反应过程 ,α-Fe与非晶 BN发生固态反应的临界晶粒尺寸约 8nm.压力和温度对反应产物及其晶体结构有明显影响 .2 GPa和 80 0 K时 ,反应产物为具有正交结构的 Fe-N新相 ;在 3～ 4 GPa和 690～80 0 K时 ,可形成单一ε-Fex N合金相 ;而在 4 GPa和 930 K以上 ,反应产物由 Fe-N合金相转变为 Fe3B相     

Pd-SiW12/SiO2催化剂上乙烯直接氧化制乙酸的反应机理

 利用积分反应器和微分反应器对Pd－SiW12／SiO2催化剂上乙烯直接氧化生成乙酸的反应机理进行了探讨．乙烯在积分反应中氧化的主要产物为乙酸（选择性为77．6％），很少生成乙醛（选择性仅为8．1％）；而在微分反应中氧化的主要产物是乙醛（选择性为98．4％）．在微分反应中分别以乙醛和乙醇为主反应物时，乙醛氧化完全生成乙酸，选择性为100％，而乙醇氧化生成乙酸的选择性低于0．15％．可以认为，在Pd－SiW12／SiO2催化剂上，水蒸气存在下乙烯主要经由中间物乙醛而生成乙酸．通过对含有不同组分和不同还原条件处理的催化剂活性的比较，认为目的反应主要发生在Pd与SiW12相互接触的部位，催化剂中的Pd0是活性Pd物种的主要形态．     

A Novel Octahedral Hexasilver(I) Cluster: Ag_6[SSCN(n-C_4H_9)_2]_6

ＣｏｍｐｏｕｎｄｓｆｏｒｍｅｄｆｒｏｍＣｕ ,ＡｇａｎｄＡｕｗｉｔｈｄｉｔｈｉｏ ｌａｔｅｌｉｇａｎｄｓ ,ｓｕｃｈａｓｔｈｅｄｉａｌｋｙｌｄｉｔｈｉｏｃａｒｂａｍａｔｅ (ＤＴＣ) ,ｍｅｒｃａｐｔｏｔｈｉａｚｏｌｉｎｅ (ＨＭＴ)ａｎｄｄｉａｌｋｙｌｄｉｔｈｉｏｐｈｏｓｐｈａｔｅｓ(ＤＤＰ) ,ｈａｖｅｐｌａｙｅｄａｎｉｍｐｏｒｔａｎｔｒｏｌｅｉｎｔｅｃｈｎｏｌｏｇｙ .1Ｃｕ(Ｉ) Ｓｃｌｕｓｔｅｒｓａｌｓｏｈａｖｅｂｅｅｎｉｍｐｌｉｃａｔｅｄｉｎｂｉｏｌｏｇｙａｓａｎ ｔｉ ｏｘｉｄａｎｔｓ .2Ｔｈｅｃｕｂａｎ…     

One Novel Vanadium-Phosphate Cluster [PV_(2.5)O_(8.5)]-3.83{H_2O} with Three-Dimensional Architecture

A novel vanadium-phosphate compound [PV_2.5O_8.5]·3.83{H_2O}(1)was obtained from the hydrothermal reac-tion and structurally characterized by elemental analysis and single-crystal X-ray diffraction,which exhibited thatthe title complex crystallized in cubic space group I-43m with crystal data:a=1.6115(1)nm,V=4.1848(1)nm~3,Z=12,D_c=1.783 g/cm~3,F(000)=2278,R_1=0.0528,and wR_2=0.1329[I>2σ(I)](all data).The basic unit of{PV_2.5O_8.5}symmetrically extended to closed sphere-like structure of{P_4V_(10)O_(34)},which was further linked to in-terleaving three-dimensional network via sharing four phosphate through μ_3-oxygen atoms around the closedsphere-like structures.     

8-羟基喹啉单体及二聚体质子转移反应的理论研究

Density functional theory （DFT） of quantum chemistry method was employed to investigate proton transfer reactions of 8-hydroxyquinoline （8-HQ） monomers and dimers. By studying the potential energy curves of the isomerization, the most possible reaction pathway was found. The total energy of 8-hydroxyquinoline was lower than that of quinolin-8（1H）-one, whereas the order was reversed in dimers. The findings explained the contrary experimental phenomena. The minimum reaction barrier of intramolecular proton transfer was 47.3 kJ/mol while that in dimer was only 25.7 kJ/mol. Hence it is obvious that proton transfer reactions of 8-HQ monomer have a considerable rate but it is easier to proceed for 8-HQ dimer than monomers. It implied that the hydrogen bond played an important role in depressing the activation energy of reaction. The mechanism of the tautomerization was discussed on the basis of theoretical results.     

The Role of Acetylcholine in the Cognitive Function of Frontal Neurons in Monkeys

To study the role of acetylcholine(ACh) in the cognitive function of frontal lobes, ACh and atropine were applied iontophoretically to the task-related neurons recorded from an area around the superior ramus of arcuate sulcus in the frontal cortex of 4 rhesus monkeys during the performance of two tasks. The spontaneous discharges and taskrelated responses of most of the neurons which increased their discharge rate in the delay and differentiation periods of the discrimination response go/no-go task and in the cue and delay periods of the delayed discrimination go/no-go task, were further increased during the application of ACh and suppressed during atropine. These results suggest that ACh may be involved in the excitatory process of the activity of the neurons in the above-mentioned area of frontal cortex to play an important role in the cognitive functions of attention, discrimination and short-term memory.