利用DPN技术直接构建磁性纳米图形

在纳米尺度下构建有序的磁性模板和图形是当前的研究热点之一 [1,2 ] .这种模板在生物样品的分离[1] 、磁电子学研究和信息存储 [2 ] 等领域具有重要意义 .目前 ,光刻 [3] 、微触点印刷 [4 ] 和自组装 [5] 等多项技术已被用来构建各种纳米模板 .1 999年 ,美国西北大学 Mirkin小组 [6 ]发明的 Dip- pen纳米刻蚀技术 (简称 DPN技术 )更在可控组装方面显示出巨大优越性 .这项技术是在一定驱动力作用下 ,使吸附在原子力显微镜 ( AFM)针尖上的分子“墨水”逐渐转移到基底表面上 ,实现纳米模板的可控构建 .与传统技术相比 ,DPN技术可在纳米尺…     

NANOSECOND KINETIC ABSORPTION AND CALORIMETRIC STUDIES OF CYCLOPENTENONE: THE TRIPLET, SELF-QUENCHING, AND THE PREDIMERIZATION BIRADICALS

The photolysis of 2-cyclopentenone has been studied by a combination of kinetic absorption spectrophotometry and time-resolved photoacoustic calorimetry. The lifetime of the cyclopentenone triplet is strongly concentration dependent and corresponds to a value of 380 +/- 75 ns at infinite dilution in acetonitrile. The biradical intermediate (or pair of isomeric biradicals) immediately preceding formation of photodimer forms with very high efficiency upon quenching of triplet cyclopentenone by a second ground state cyclopentenone molecule and has an energy of 47 kcal/mol relative to two molecules of reactant. Quenching of the cyclopentenone triplet by conjugated dienes is much slower than expected, which is the reason that early estimates of the triplet lifetime were much too short.     

在线标准加入火焰原子吸收光谱法测定钮扣电池中铅和镉

应用火焰原子吸收光谱(FAAS)法测定了钮扣电池中铅和镉的含量,对测定条件作了较详细的研究。用在线双毛细管标准加入法消除了基体的干扰。按所述方法测定电池样品中铅和镉,测定结果的RSD依次为3.58%和5.87%,铅和镉的浓度水平分别为5.4×10-3%和2.3×10-4%(质量分数),回收率结果为93.0%~100.1%(铅)和95.0%~101.0%(镉)。     

水热改性对NiMo/γ-Al2O3加氢脱氮催化剂结构及性能的影响

The influence of hydrothermal modification on the structure and hydrodenitrogenation (HDN) activity of NiMo/γ-Al₂O₃catalyst was studied in the range 140～180 ℃. The experimental results indicated that the hydrodenitrogenation reaction rate of pyridine was accelerated using the NiMo/γ-Al₂O₃catalyst synthesized via hydrothermal route due to the change of the structure, the increase of the amount of Mo and Ni and the rise of the specific surface area. The change of the structure of catalysts was enhanced at higher hydrothermal temperature, producing NiMo/γ-Al₂O₃catalyst with better HDN activity.     

金负载量对低温水煤气变换Au/α-Fe2O3催化剂结构和性能的影响

采用共沉淀法制备了低温水煤气变换Au/α-Fe2O3催化剂。通过正交实验优化催化剂的还原活化条件，考察了金负载量对催化剂性能的影响。采用BET、XRD、UV-VIS、XRF、H2-TPR和O2-TPO等表征手段对催化剂的结构进行分析，并与其催化性能进行关联。结果表明，（1）采用10%-H2/N2还原气将催化剂在150 ℃原位还原9 h，其催化活性最高；（2）金的最佳负载量为8.00%，此时在催化剂制备过程中金的流失量较少，金粒子较小，也有利于抑制催化剂在反应过程中烧结；（3）TPR-TPO结果表明，金的负载量为8.00%时，Au/α-Fe2O3催化剂具有较易被还原、不易被氧化的性质，从而显示出最高催化活性。（4）Au/α-Fe2O3催化剂中的金以单质金（Au0）形式存在；其高活性与Au0-Fe3O4间的协同作用有关。     

Synthesis and Crystal Structure of a Tetranuclear Silver Complex with Bis（diphenylphosphino） amine-dioxide as a Tridentate Ligand

1 INTRODUCTION The coordination chemistry of the nitrogen-contai- ning diphosphine ligand bis(diphenylphosphino)ami- ne (Ph2PNHPPh2) has recently received much atten- tion because the P atoms can bridge metal centers in μ-bonding mode to form bi- or polynuclear complex- es[1~10]. It has been shown that the acidity of N–H proton would promote functionalization on the ligand backbone[4, 5, 11]. Although a few complexes contain- ing deprotonated tridentate Ph2PNPPh2 have been synthesi…     

REE AND Sr, Nd, Pb ISOTOPIC GEOCHEMISTRY OF HUANGYISHAN BASALT, KUANDIAN, LIAONING, NORTHEAST CHINA

In the light of major element geochemistry, mineral chemistry and REE and isotopic data, the small but apparent isotopic differences between the Cenozoic volcanic rocks east and west of the Tancheng-Lujiang fault are believed to be caused by the mixing and metasomatism of crustal and mantle material in tho mantle source region in response to Pacific plate subduction. The presence of phlogopite and pargasite in mantle xenoliths lends strong support to mantle metasomatism.     

液晶聚酯与环氧嵌段共聚物的合成及表征

近年来 ,人们利用高分子液晶作为热固性环氧树脂的改性剂 ,不仅可以提高环氧树脂的韧性和强度 ,而且可以改善其热性能 ,为制备高性能的环氧树脂提供了一条新的途径[1,2 ] .目前报道所使用的液晶聚合物大多为液晶聚酯[3 ] 或液晶性聚氨酯[4] ,这些液晶聚合物与环氧树脂由于存在相容性不好的问题 ,给其实际应用带来了困难 .为了改善二者的相容性 ,本文采用溶液法合成了末端带有反应活性基团的聚酯型液晶聚合物 ,将它再与双酚Ａ环氧预聚物反应 ,制得了高分子液晶环氧嵌段共聚物 ,其合成路线如下 :2ＨＯＣＯＯＣＨ3+ ＨＯ(ＣＨ2 ) 6 ＯＨ　　Ｈ…     

配合物Cu(phen)2 (dca)2的合成及晶体结构

合成了配合物Cu(phen)2 (dca)2(phen=C12H8N2为1,10-邻菲啰啉,dca-为二氰基氨基阴离子),用IR对其结构进行了初步表征,并测定了配合物的晶体结构.该晶体属单斜晶系,空间群为P21/c;晶胞参数a=0.8869(2)nm,b=1.4691(2)nm,c=1.9298(2)nm,β=100.90(1)°;V=2.4691(8)nm3,Z=4,F(000)=1132.00,Dc=1.496g/cm3,R=0.051,RW=0.068.中心铜(Ⅱ)离子分别与两个phen中的四个N原子和两个dca-的两个N原子配位,形成六配位的变形八面体结构.     

新型双核铜配合物的合成,表征及其对苯乙烯环氧化的催化作用

设计合成了５种新型双核铜配合物，用ＥＡ，ＩＲ，ＵＶ－Ｖｉｓ，ＸＰＳ，ＥＰＲ等进行了结构表征，并研究了这些Ｃｕ２配合物模拟双核铜单加氧酶多巴胺β－羟化酶催化苯乙烯环氧化反应的特征。结果表明，这些配合物具有两种类型的结构：脱质子型Ｃｕ２ＬＯＨ和非脱质子型「（Ｃｕ２Ｈ２ＬＸ）Ｙ」Ｙ（Ｘ＝Ｙ＝Ｃｌ＾１－，Ｂｒ＾－；Ｘ＝ＯＨ，Ｙ＝Ｏ２ＣｌＯ＾－２），两类配合物可相互转化。非脱质子型配合物催化ＰｈＩＯ对苯乙烯