催化动力学光度法测定微量钯

在硫酸 ( 1 + 1 )介质中 ,Pd(Ⅱ )催化过氧化氢氧化酸性铬蓝K的褪色反应。研究了反应的最佳条件 ,建立了催化光度法测定痕量钯的新方法。方法的最低检测限为 5 97× 1 0 - 4 μg/mL。线性范围为 5 97× 1 0 - 4 ～ 2 60× 1 0 - 2 μg/mL。该法用于合成样品和含钯催化剂的分析     

[Co(ptma)(amp)Cl]2+体系的一反式经式异构体(m3[ZnCl4]·0.5H2O)的晶体结构

在合成[Co(bpma)(tn)Cl]²⁺体系配合物的实验中,得到[Co(ptma)(amp)Cl]²⁺体系的一反式(ptma中仲胺上的氢相对于Cl)经式异构体(m3[ZnCl₄]·0.5H₂O),其中bpma=N,N′-二(2-吡啶基甲基)胺,tn=1,3丙二胺,ptma=N-(2-吡啶基甲基)丙二胺,amp=2-(氨基甲基)吡啶。此配合物异构体构型选择性形成的原因可能主要是其结构中配体间C-H…π相互作用使之更稳定的结果。利用单晶X-射线衍射法测定的晶体学参数:单斜晶系,空间群C2/c,a=1.55978(19)nm,b=1.33324(16)nm,c=2.2077(3)nm,β=94.832(3)°,V=4.5748(10)nm³,D_c=1.696g·cm^-3,Z=8,F₀₀₀=2360,μ(MoKα)=23.72cm^-1,R=0.0475,R_w=0.1204。配合物离子中Co³⁺为六配位。晶胞中含8个配合物阳离子,8个[ZnCl₄]^2-阴离子及4个水分子,对映体的比例为1∶1。     

THE COMPARISON OF LANZHOU LOESS PROFILE WITH VOSTOK ICE CORE IN ANTARCTICA OVER THE LAST GLACIATION CYCLE

Loess near Lanzhou in the late Pleistocene is very sensitive to climatic fluctuations. The Beiyuan terrace profile in Linxia City, of which the curve of susceptibility tallies with the trend of isotopic curves of Vostok 2083 m ice core in Antarctica, is 35m thick. There are five layers of paleosols under Malan loess(L_1). Upper three layers (S_(1-a),S(1-b)and S_(1-c) correspond to three warm stages in last interglaciation, Interstadial of Last Glacial (C stage in Antarctic ice core)was clearly recorded in the Beiyuan profile, in which three layers of paleosols and two of loess were formed. The lowest section of the profile belongs to penultimate glaciation, in which fossils of cold-drought-resistant mammal and mollusc have been discovered.     

高选择性透过二氧化硫气体分离膜的研究 （Ⅳ）不同烃基乙烯基亚砜接枝聚乙烯醇膜的透过性能

研究了不同烃基乙烯基亚砜接枝聚乙烯醇（ＰＶＡ－ＲＶＳＯ，Ｒ＝Ｍｅ，Ｅｔ，ｔ－Ｂｕ，Ｐｈ）膜对纯ＳＯ２、Ｎ２的透过性能以及ＳＯ２／Ｎ２混合气体的分离性能．结果表明上述膜对ＳＯ２具有高的选择性．对不同烃基乙烯基亚砜接枝膜进行了比较．     

一锅法制备全乙酰吡喃溴代糖

将未保护的吡喃糖与醋酸酐在分子碘的催化下制得全乙酰吡喃糖 ,随后不经分离直接与溴化氢的冰醋酸溶液( 4 5 %)反应得到全乙酰吡喃溴代糖 .这种一锅法制备全乙酰吡喃溴代糖操作方便 ,收率高 ,经济实用且对环境友好     

Surface chemistry of nanoscale Fe_3O_4 dispersed in magnetic fluids

The interaction between stabilizers and nanoparticles is one of the important factors to prepare stable magnetic fluids. The magnetic nano-size Fe3O4 core with single domain and the average grain size around 8-12 nm were prepared by chemical precipitation method. The O/Fe molar ratio of the particle surface was measured by X-ray photoelectron spectroscopy (XPS). The heat effects of stabilizers ad- sorption on nanoparticles were measured by solution calorimetry. The excess amount of oxygen was possibly the result of the hydroxygen formed on the surface of the nanoparticles. The heat effects showed that compounds containing carboxyl groups can be adsorbed chemically on magnetite by forming chemical bonds. The other stabilizers involving NH-groups, such as polyethylene-imine, can be adsorbed physically. The exothermic value is about half of the former case.     

滇紫草及露蕊滇紫草的氨基酸和元素分析

为分析滇紫草及露蕊滇紫草中的氨基酸和元素含量，将样品用酸处理后，采用氨基酸分析仪及电感耦合等离子体发射光谱仪进行了测定。结果表明，两种紫草含有18种氨基酸及14种元素。可见滇紫草及露蕊滇紫草问氨基酸和元素含量没有重大的差异。     

Studies on Colloidal Properties of Mixed Metal Hydroxide－Clay Aqueous Suspension

ＳｔｕｄｉｅｓｏｎＣｏｌｌｏｉｄａｌＰｒｏｐｅｒｔｉｅｓｏｆＭｉｘｅｄＭｅｔａｌＨｙｄｒｏｘｉｄｅ－ＣｌａｙＡｑｕｅｏｕｓＳｕｓｐｅｎｓｉｏｎＮＯＵｗａｎ－ｇｕｏ；ＺＨＡＮＧＣｈｕｎ－ｇｕａｎｇ；ＳＵＮＤｅ－ｊｕｎ；ＨＡＮＳｈｕ－ｈｕａａｎｄＷＡＮＧ...     

液相色谱-串联质谱法同时检测饲料中多种抗氧化剂

饲料中添加抗氧化剂能够阻止或延缓饲料中某些营养物质氧化,延长饲料贮存期,从而提高饲料利用率.     

反应挤出法合成S/B多嵌段共聚物的研究

在阴离子引发体系下 ,以双螺杆挤出机为反应器 ,采用丁二烯、苯乙烯混和单体加料方式 ,本体法一步合成了S B多嵌段共聚物 .考察了螺杆转速、进料速率以及不同丁苯配比对反应挤出合成PS及S B嵌段共聚物聚合转化率的影响 .用1 H NMR、IR、DMA、TEM等方法对S B嵌段共聚物进行了表征 ,结果表明共聚物由多个微小的丁二烯嵌段和少量无规段组成 .当丁二烯含量少至 15 %左右时 ,其嵌段可回缩成球状 ,粒径大约在 30～ 5 0nm .该材料的韧性随着共聚物中丁二烯含量的增加而逐渐提高 ,特别是断裂延伸率的提高尤为显著