Tectonic setting discrimination and40Ar/39Ar isotope geochronology of the Miba granite

The Miba granite is located in the juncture of Kang County in eastern Gansu Province and Lueyang County in Shanxi Province. It is considered to be the post-orogenic granite (POG-type) by major element discrimination method of Maniar.⁴⁰Ar/³⁹Ar dating indicates that its emplacement time is about 240—230 Ma and it is the result of the Indo-Sinian magmatism. In the early Yanshan period (about 193.8 Ma), a thermal event resulted in the partial opening of the argon isotope system of the biotite.

     

Unroofing around Qaidam Basin of northern Tibet at 30 Ma: constraints from ~(40)Ar/~(39)Ar and FT thermochronology on granitoids

An ~(40)Ar/~(39)Ar and fission track thermochronological study has been carried out on threesuites of granitoids collected along the northern and southern edges of the Qaidam Basin to betterconstrain the mechanisms accommodating the India-Asia collision around the Qaidam Basin(northern Tibet), in order to understand the evolution of the entire deformation area. Mica andK-feldspar have been analyzed and the cooling histories of the latter have been modeled. Thecooling histories based upon K-feldspar modeling and fission track ages show that samples simul-taneously recorded an important cooling event (7.5-10.7℃/Ma) around 30 Ma, which is thoughtto reflect an increase of denudation rate related to the tectonic activity in this area associated withuplift suggesting significant crustal thickening starting around 30 Ma in this area. The estimatedsedimentation rate in the Qaidam Basin, the propagation rate along the Altyn Tagh fault and fieldobservations support this deduction.     

Tectonic setting discrimination and<Superscript>40</Superscript>Ar/<Superscript>39</Superscript>Ar isotope geochronology of the Miba granite

The Miba granite is located in the juncture of Kang County in eastern Gansu Province and Lueyang County in Shanxi Province. It is considered to be the post-orogenic granite (POG-type) by major element discrimination method of Maniar.⁴⁰Ar/³⁹Ar dating indicates that its emplacement time is about 240—230 Ma and it is the result of the Indo-Sinian magmatism. In the early Yanshan period (about 193.8 Ma), a thermal event resulted in the partial opening of the argon isotope system of the biotite.     

Magmatism and deformation times of the Xidatan rock series, East Kunlun Mountains

The Xidatan rock series consist of mylonite, gneiss and granite. The U-Pb age showsthat the granite was formed at 206 Ma, and the ~(40)Ar/~(39)Ar ages of the biotite display that the my-lonite was formed at 145 Ma when the Xidatan ductile shear zone occurred. At about 110-100 Mathe Xidatan Fault reactivated again. As a result, the biotite and muscovite of Xidatan rock seriesopened their argon isotope system.     

C40,Nb@C40^＋,La@C40^＋的从头算研究

用量子化学从头算方法研究了Ｃ４０、Ｎｂ＠Ｃ４０＾＋，Ｌａ＾＠Ｃ４０＾＋的几何构型和电子结构，Ｃ４０最稳定构型具有Ｄ２对称性。Ｌａ和Ｎ原子内含于Ｃ４０笼中，形成金属夹心碳笼Ｎｂ＠Ｃ４０＾＋、Ｌａ＠Ｃ４０＾＋。Ｃ４０结合能大于Ｍ＠Ｃ４０＾＋（Ｍ＝Ｎｂ，Ｌａ）。     

[SiNi(H2O)W11O39]6-多层组装膜修饰电极及其电化学行为

采用电化学生长法制备包含杂多酸[SiNi(H2O)W11O39]6-(SiNiW11)和聚合物阳离子PDDA的多层膜修饰电极, 利用循环伏安法研究其电化学行为、 pH的影响及其对BrO3-和NO2-体系还原的电催化性能;并对多层膜电化学过程机理进行了初步探讨. 结果表明: 多层膜的增长均匀, 峰电流随层数的增加而增加;多层膜的峰电流随扫速的增加而增加;还原峰的峰电位随pH的增加而负移.     

[SiZn(H2O)W11O39]6-在玻碳电极上的多层组装及电催化性能

采用循环伏安法研究一取代硅钨杂多酸在酸性水溶液中的电化学行为及pH的影响.制备了包含杂多酸[SiZn（H2O）W11O39]%6-（SiZnW11）和聚合物阳离子-聚二烯丙基二甲基氯化铵（PDDA）的多层膜修饰电极,研究了其电化学行为.逐层的循环伏安行为表明膜的增长均匀,峰电流随膜层数的增加而增加,与其在液中的氧化还原行为相比,多层膜中的SiZnW11显示出一些特殊的性质.对BrO3^-和NO2^-体系的还原具有良好的电催化性能.     

ZrO2／SO4^2—超强酸体系形成过程的研究

本文用XRD、TG-DTG-DTA、SEM和化学分析等多种实验手段研究了浸渍H_2SO_4的无定形ZrO_2在不同焙烧温度下的晶化和相变,失水和失硫等过程.实验结果表明,这些过程与超强酸的形成密切相关,在ZrO_2/SO_4~(2-)超强酸体系中不存在水和游离H_(2)SO_(4),体系超强酸强度最高时ZrO_2呈四方晶相,晶体表面约有略少于1/3的Zr原子与SO_4~(2-)根相结合.     

CP/MAS ~(13)C NMR技术对木浆纤维微观结构的研究

利用交叉极化结合魔角旋转技术~(13)C核磁共振法(CP/MAS ~(13)C NMR)对桉木浆纤维的微观结构进行研究,为进一步研究木质纤维素材料开发过程中反应障碍特征奠定基础.通过对NMR光谱C1区(δ 102～108)进行洛仑兹拟合,得到桉木浆纤维中纤维素Iα的相对含量为26.92%,纤维素Iβ的相对含量为52.04%,主要以纤维素Iβ晶体形式为主.通过计算纤维素C4结晶区(δ 86～92)和非结晶区(δ 80～86)的相对含量得到桉木浆的纤维素结晶度为47%.通过洛仑兹和高斯函数的混合模型对NMR光谱C4区(δ 80～92)进行拟合得到基原纤尺寸和微原纤横向尺寸分别为4.0与17.9 nm,并通过计算不同形态的结晶纤维素的相对含量得到纤维素结晶度为51%,证实了在微原纤内部次晶纤维素的存在.     

Four-Level Decay Model of~6P_(7/2) Excited State of Eu~(2+) Ion in KMgF_3

Optical transitions of divalent Europium (4f7) ions in KMgF3 have been investigated extensively due to the potential applications for phosphors or lasers. In KMgF3: Eu2+, the 6P7/2 state is at lower energy than the lowest 4f65d state. However, the reported energy differences between the two states vary from author to author. Sardar et al.1 estimated the value of 1250 cm-1 from a semilog plot of the 6P7/2?8S7/2 and 4f65d? 8S7/2 emission intensities versus T-1. Altshuler et al.2 found the …     

General Route for the Preparation of Diverse 17-Membered Macrocycles Based on RCM and Examination of the E/Z Selectivity

A convergent, general synthetic route to 17-membered macrocycles was developed to support biological evaluation and structure–activity relationship (SAR) studies during phenotypic screening for immunology targets. A series of amide coupling reactions led to a ring-closing metathesis (RCM) precursor that was cyclized using Grubbs' catalysts. It was found that the reaction formed the macrocyclic products in a 3:1 ratio of E/Z isomers. Moreover, it was shown that a number of similarly substituted RCM precursors undergo cyclization to produce the geometric E/Z isomers in roughly the same 3:1 ratio. The remarkable independence of the E/Z outcome from the substitution pattern of the RCM precursor makes this synthetic approach generally applicable. Separation of the E/Z isomers was achieved by preparative high-performance liquid chromatography and allowed biological profiling of the geometric isomers. Reactive groups in the macrocycle were utilized for late-stage modifications in the fashion of diversity-orientated synthesis (DOS), yielding analogs for SAR studies.     

The Synthesis and Characterization of High Molecular Weight Poly（phenylene sulfide/ether）

Poly(p-phenylene sulfide) (PPS) is a high performance engineering thermoplastic with high temperature resistance, good chemical resistance and mechanical properties. Since it was commercialized by Phillips Petroleum Company in 1973, it has been widely use…     

Development of isotope dilution-liquid chromatography/mass spectrometry combined with standard addition techniques for the accurate determination of tocopherols in infant formula

During the development of isotope dilution-liquid chromatography/mass spectrometry (ID-LC/MS) for tocopherol analysis in infant formula, biased measurement results were observed when deuterium-labeled tocopherols were used as internal standards. It turned out that the biases came from intermolecular H/D exchange and intramolecular H/D scrambling of internal standards in sample preparation processes. Degrees of H/D exchange and scrambling showed considerable dependence on sample matrix. Standard addition-isotope dilution mass spectrometry (SA-IDMS) based on LC/MS was developed in this study to overcome the shortcomings of using deuterium-labeled internal standards while the inherent advantage of isotope dilution techniques is utilized for the accurate recovery correction in sample preparation processes. Details of experimental scheme, calculation equation, and uncertainty evaluation scheme are described in this article. The proposed SA-IDMS method was applied to several infant formula samples to test its validity. The method was proven to have a higher-order metrological quality with providing very accurate and precise measurement results.     

丙烯酸与纤维素在60Co辐照下的接枝聚合反应

高吸水性树脂是一类高分子功能材料，吸水量大、保水性强，可以吸收比自身重量高几百到几千倍的水，而且所吸人的水在适当的压力下也不会被挤出。60年代初美国最早开始淀粉接枝丙烯腈研究，随后国内外学者又用纤维素或其衍生物与丙烯腈、丙烯酸酯等单体接枝聚合，经碱液水解后而得。纤维素类高吸水树脂虽然吸水倍率不很高，但吸水速度较快，吸水后形成的凝胶强度较大，其单体制备严格条件下，纤维素要经过活化，要有引发剂诱导，还要通氮气，在一定温度下反应才能进行。本文采用纤维素与丙烯酸在常温和辐照条件下，无需活化、引发剂和氮气保护，即可进行接枝聚合而制备高吸水材料。     

Effect of Ultraviolet Irradiation on Structure and Properties of HDPE and HDPE/STC Blends

Abstract

Some oxygen‐containing groups such as C?O and C–O were introduced onto high‐density polyethylene (HDPE) chains by an ultraviolet irradiation technique without the addition of any additives, and this method causes no chemical pollution to the environment. This groups content increases with irradiation time. Gelation took place in the HDPE irradiated for 16?hr, and the gel content also increases with irradiation time. After irradiation, the crystal shape and crystalline plane spacing of HDPE remained unchanged; the melting temperature decreased, whereas the crystallinity and hydrophilicity increased. Due to the introduction of polar groups, the interfacial interaction between sericite–tridymite–cristobalite (STC) particles and irradiated HDPE, and the mechanical properties of irradiated HDPE/STC (60/40) blend were improved. Compared with the yield and impact strength of HDPE/STC (60/40) blend, those of the corresponding blend irradiated for 16?hr were increased from 25.1?MPa and 56?J/m to 29.1?MPa and 283?J/m, respectively.     

杂多酸盐在Raney Ni和Raney Co表面上的状态

采用XPS表面分析技术研究了Cu3/2PMo12O40改性Raney Ni和Raney Co的表面状态,结果表明,Raney Ni和Raney Co表面上的Cu3/2PMo12O40分子中的Cu2＋和Mo6＋发生了很大变化,Cu2＋被还原为Cu0,而Mo6＋被部分还原为Mo5＋和Mo4＋.这些变化可归因于Raney Ni和Raney Co在制备过程中表面吸附的活泼氢所致.由于Raney Ni表面吸附的氢比Raney Co表面吸附的氢的活性高,使得Raney Ni表面的Mo6＋被还原到Mo5＋和Mo4＋的量多.混合价态Mo的存在提高了羰基在催化剂表面吸附和活化的能力,同时Cu0的存在有助于羰基的加氢反应.所以,混合价态的Mo和Cu0对羰基加氢起着协同的作用.     

单糖和硼酸形成络合物的讨论

本文用平均络合平衡常数的测定及~(13)C NMR两种方法对一些单糖、糖苷和硼酸生成的络合物进行了研究。研究结果表明醛戊糖、醛己糖虽在溶液中主要以吡喃环存在,但当它们与硼酸络合时即由吡喃转变成呋喃。     

Chemoselective Reduction of Azides to Amines Using Sm/TMSCl System in the Presence of Trace Amounts of Water

Samarium diiodide and organosamarium compounds have been widely employed as useful reagents in organic synthesis1. However, relatively few reports on the direct use of samarium metal in organic synthesis have been reported2, because the surface of samarium metal is inactive3. In order to improve the activity of samarium, some additives, such as HgCl24, NH4Cl (aq.)5, or TMSCl6 were added.The reduction of azides to the corresponding amines is an important reaction in organic synthesis7-16. A…     

表面In掺杂TiO2的N719/TiO2-Inx%/FTO薄膜电极的光电转换效率

采用溶胶-凝胶法制备出In 表面修饰的TiO₂ (TiO₂-Inx%)纳米粒子, x%代表在In 掺杂的TiO₂样品中In³⁺与In³⁺和Ti⁴⁺离子摩尔百分含量. 利用二(四丁基铵)顺式-双(异硫氰基)双(2,2''-联吡啶-4,4''-二羧酸)钌(II)(N719)作为敏化剂, 制备出N719/TiO₂/FTO (氟掺杂锡氧化物)和N719/TiO₂-Inx%/FTO染料敏化薄膜电极. 光电转换效率实验表明, 在薄膜电极+0.5 mol·L^-1 LiI+0.05 mol·L^-1 I₂的三甲氧基丙腈(MPN)溶液+Pt 光电池体系中,N719/TiO₂-Inx%/FTO薄膜电极的光电转换效率均高于N719/TiO₂/FTO, 其中N719/TiO₂-In0.1%/FTO的光电转换效率比N719/TiO₂/FTO提高了20%. 利用X 射线衍射(XRD)、X 射线光电子能谱(XPS)、漫反射吸收光谱(DRS)、荧光(PL)光谱和表面光电流作用谱确定了TiO₂-Inx%样品中In3+离子的存在方式和能带结构; 利用表面光电流作用谱研究了N719/TiO₂-Inx%/FTO薄膜电极的光致界面电荷转移过程. 结果表明, In3+离子在TiO₂表面形成O-In-Cl_n (n=1, 2)物种, 该物种的表面态能级位于导带下0.3 eV处; 在光电流产生过程中, O-In-Cl_n (n=1, 2)表面态能级有效地抑制了光生载流子在TiO₂-Inx%层的复合, 促进了阳极光电流的增加, 从而导致N719/TiO₂-Inx%/FTO薄膜电极的光电转化效率高于N719/TiO₂/FTO, 并进一步讨论了光致界面电荷转移的机理.     

NO2在Ag/Pt(110)双金属表面上的吸附和分解

利用俄歇电子能谱(AES)和程序升温脱附谱(TDS)研究了NO₂在Ag/Pt(110)双金属表面的吸附和分解.室温下NO₂ 在Ag/Pt(110)双金属表面发生解离吸附, 生成NO(ads)和O(ads)表面吸附物种. 在升温过程中NO(ads)物种发生脱附或者进一步分解. 500 K时NO₂在Ag/Pt(110)双金属表面发生解离吸附生成O(ads)表面吸附物种. Pt 向Ag传递电子, 从而削弱Pt－O键的强度, 降低O(ads)从Pt 表面的并合脱附温度. 发现能够形成具有稳定组成的Ag/Pt(110)合金结构, 其表现出与Pt(110)-(1×2)相似的解离吸附NO₂能力, 但与O(ads)的结合明显弱于Pt(110)-(1×2). 该AgPt(110)合金结构是可能的低温催化直接分解氮氧化物活性结构.