Study of High-Order Harmonic at VUV/XUV

Ｓｔｕｄｙ　ｏｆ　Ｈｉｇｈ－Ｏｒｄｅｒ　Ｈａｒｍｏｎｉｃ　ａｔ　ＶＵＶ／ＸＵＶＳｔｕｄｙｏｆＨｉｇｈ－ＯｒｄｅｒＨａｒｍｏｎｉｃａｔＶＵＶ／ＸＵＶ￥ＺＨＵＡＮＧＤｏｕｎａｎ；ＬＥＩＳｈｉｚｈａｎ；ＹＵＧｕｉｑｉｕ；ＲＥＮＺｈａｏｙｕ；ＭＡＪｉｎｇｍｉ...     

基于扩散速度方法粘性流场的离散涡数值模拟

基于扩散速度方法粘性流场的离散涡数值模拟吴文权，李春，卜千里（上海机械学院上海２０００９３）关键词：扩散速度模型，粘性流场，离散涡方法。ＮＵＭＥＲＩＣＡＬＳＩＭＵＬＡＴＩＯＮＯＦＶＩＳＣＯＵＳＦＬＯＷＦＩＥＬＤＳＵＳＩＮＧＤＩＦＦＵＳＩＯＮＶＥＬＯＣ...     

PUSHING THE ENVELOPE IN RAMAN SPECTROSCOPY

ＰＵＳＨＩＮＧＴＨＥＥＮＶＥＬＯＰＥＩＮＲＡＭＡＮＳＰＥＣＴＲＯＳＣＯＰＹＧ．Ｄ．Ｐｉｔｔ（ＵｎｉｖｅｒｓｉｔｙｏｆＬｅｅｄｓａｎｄＲｅｎｉｓｈａｗｐｌｃＵ．Ｋ）ＮｅｗｔｅｃｈｎｉｑｕｅｓｈａｖｅｂｅｅｎｄｅｖｅｌｏｐｅｄｆｏｒＵＶＲａｍａｎｍｉｃｒ...     

会议消息

会议消息ＦＩＦＴＨＩＮＴＥＲＮＡＴＩＯＮＡＬＣＯＮＧＲＥＳＳＯＮＳＯＵＮＤＡＮＤＶＩＢＲＡＴＩＯＮ￥ＵｎｉｖｅｒｓｉｔｙｏｆＡｄｅｌａｉｄｅ，ＳｏｕｔｈＡｕｓｔｒａｌｉａＤｅｃ．１５～１８３１９９７第五届国际声和振动会议将于１９９７年１２月１５～１８...     

硫化镉胶体体系光反应产生的自由基的研究

本文作者制备了硫化镉的十二烷基磺酸钠胶体，测定了其ＵＶ－Ｖｉｓ吸收光谱和荧光发射光谱，用自旋捕捉－ＥＳＲ技术研究了一些无机盐，有机盐和几种有机物分别在ＣｄＳ／ＳＤＳ胶体系中的光反应产生的活泼自由基。     

二维核磁共振谱解析及其应用

２ＤＮＭＲ在波谱学的化学应用中占据首要位置。本文简述了ＣＯＳＹ，ＬＲＣＯＳＹ，ＣＯＳＹＤＥＣ，ＳＥＣＳＹ，ＤＱＣ－ＣＯＳＹ，ＲＣＴ，ＩＮＡＤＩＱＵＡＴＥ，ＲＥＬＡＹ，ＩＮＶＥＲＳＥ，ＮＯＥＳＹ，ＨＯＥＳＹ，ＯＨＡＨＡ，ＲＯＥＳＹ，ＨＭＱＣ，ＨＭＢＣ等谱的形状，指认步骤及其应用。     

书评

书评ＣＯＮＣＥＲＴＡＮＤＯＰＥＲＡＨＡＬＬＳＨＯＷＴＨＥＹＳＯＵＮＤＬｅｏＬＢｅｒａｎｅｋ著，Ｖｉｉｉ＋６４３页，美国物理协会为声学学会出版，１９９６年３月。书店售价为４９９５美元。科学学会和专业学会会员直接向英国ＯｘｆｏｒｄＵｎｉｖｅｒｓｉｔｙＰｒ...     

Analytic Subject Index to Volume BS,(1996 )

ＡｎａｌｙｔｉｃＳｕｂｊｅｃｔＩｎｄｅｘｔｏＶｏｌｕｍｅＢＳ，（１９９６）ＬＡＳＥＲＤＥＶＩＣＥＳＰＵｌｓｅｗｉｄｔｈｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆｍｏｄｅ－ｌｏｃｋｅｄＴｉ：ｓａｐｐｈｉｒｅｌａｓｅｒｗｉｔｈｒｉｎｇｃａａｖｉｔｙＫｅｒｒ－ｌｅ...     

TOTAL CROSS SECTION MEASUREMENTS FORELECTRONSCATTERINGONMETHANEBETWEEN1AND50eV

ＴＯＴＡＬＣＲＯＳＳＳＥＣＴＩＯＮＭＥＡＳＵＲＥＭＥＮＴＳＦＯＲＥＬＥＣＴＲＯＮＳＣＡＴＴＥＲＩＮＧＯＮＭＥＴＨＡＮＥＢＥＴＷＥＥＮ１ＡＮＤ５０ｅＶＬｉＴａｉｈｕａＹｅＲｕｉｙｉｎｇＹａｎｇＹｏｎｇＣｅｎｔｅｒｆｏｒＲａｄｉａｔｉｏｎＰｈｙｓｉｃｓ...     

THE MACQM CALCULATION OF THE TOTAL ENERGY CURVE FOR THE ICOSAHEDRAL CENTRAL STRUCTURE OF THE CLUSTER H_13~-

ＴＨＥＭＡＣＱＭＣＡＬＣＵＬＡＴＩＯＮＯＦＴＨＥＴＯＴＡＬＥＮＥＲＧＹＣＵＲＶＥＦＯＲＴＨＥＩＣＯＳＡＨＥＤＲＡＬＣＥＮＴＲＡＬＳＴＲＵＣＴＵＲＥＯＦＴＨＥＣＬＵＳＴＥＲＨ－１３ＺｈａｎｇＪｉａｎｐｉｎｇ＊ＬｉＰｉｎｇＧｏｕＱｉｎｇｑｕａｎＩｎｓｔ...     

Application of Mössbauer Spectroscopy to the Carbon Oxides Hydrogenation Reactions

Iron-based catalysts have favorable activity and selectivity properties for the CO and CO₂ hydrogenation reactions. Several Fe phases (oxides and carbides) can be present in these catalysts. The interaction of Fe with the other components of the catalyst (support, promoters) can affect the ease of reduction and also its transformation during the reactions. In this work, the relationship between catalytic behavior in the CO and CO₂ hydrogenation reactions and the Fe phase composition of fresh and reacted catalysts was studied. Two types of catalysts were tested: a laterite and the other one made of iron supported on alumina, both unpromoted and promoted with K and Mn. Only those Fe species which can be reduced-carburized, by means of a pretreatment or by an in situ transformation under the reaction, seem to be able to perform the CO or CO₂ hydrogenation. The reoxidation of the Fe carbide to magnetite was not associated to deactivation. The selectivity seems to be more affected by Fe species difficult to reduce than by magnetite produced by reoxidation. This revised version was published online in July 2006 with corrections to the Cover Date.     

EXAFS study of model Pd/Ga2O3 catalysts for the liquid-phase hydrogenation of acetylene before and after the reaction

The catalytic characteristics of Pd/Ga₂O₃ samples in the liquid-phase hydrogenation of acetylene to ethylene are studied. The structure of the catalyst’s components before and after the reaction is examined by EXAFS spectroscopy. The activity of the original (after drying) samples results from the reduction of the original palladium oxide to a metallic state in the reaction medium. According to EXAFS, the catalysts reduced at 200°C contain small amounts of Pd-Ga alloy that was preserved in the reaction medium during the liquid-phase hydrogenation of acetylene and presumably increased the activity and selectivity of the samples.     

Pd/C催化剂在乙炔选择加氢反应中的催化性能：载体效应

Pd/C catalysts were prepared by deposited Pd nanoparticles (NPs) on different carbon supports including activated carbon (AC), graphite oxide (GO), and reduced graphite oxide (rGO) using sol-immobilization method. Through transmission electron microscopy, powder X-ray di raction, and X-ray photoelectron spectroscopy, the role of the carbon supports for the catalytic performances of Pd/C catalysts was examined in selective hydrogenation of acetylene. The results indicate that Pd/AC exhibited higher activity and selectivity than Pd/GO and Pd/rGO in the gas phase selective hydrogenation of acetylene. Thermal and chemical treatment of AC supports also have some effect on the catalytic performance of Pd/AC catalysts. The differences in the activity and selectivity of various Pd/C catalysts were partly attributed to the metal-support interaction.     

Influence of morphology in the catalytic activity of bioconjugated platinum nanostructures

Platinum nanoparticles stabilized by a protein, bovine serum albumin, have been synthesized successfully with two different morphologies such as cuboctahedra and nanorods. They have been characterized by the use of different techniques such as XPS, PCS, TEM, and STEM-HAADF. These nanoparticles have been applied as catalysts for the hydrogenation of allyl alcohol in an aqueous solution. A key finding of this article is the superior catalytic activity of the nanorods compared to the cuboctahedral particles. This difference in the catalytic activity was justified because of the variation in the amount of protein to stabilize the nanorods. A model for the nanorods and equations that describe the proportion of atoms in the different sites of the particle (face, vertex, edge, or interior) is used to calculate the percentage of atoms that are located on the nanorod surface. The stability of these particles as catalysts was also studied. The results showed that Pt nanorods and Pt cuboctahedra particles were degraded after 24 h of reaction.     

Potential application of palladium nanoparticles as selective recyclable hydrogenation catalysts

The search for more efficient catalytic systems that might combine the advantages of both homogeneous (catalyst modulation) and heterogeneous (catalyst recycling) catalysis is one of the most exciting challenges of modern chemistry. More recently with the advances of nanochemistry, it has been possible to prepare soluble analogues of heterogeneous catalysts. These nanoparticles are generally stabilized against aggregation into larger particles by electrostatic or steric protection. Herein we demonstrate the use of room temperature ionic liquid for the stabilization of palladium nanoparticles that are recyclable catalysts for the hydrogenation of carbon–carbon double bonds and application of these catalysts to the selective hydrogenation of internal or terminal C=C bonds in unsaturated primary alcohols. The particles suspended in room temperature ionic liquid show no metal aggregation or loss of catalytic activity even on prolonged use.     

Sonochemical enantioselective hydrogenation of ethyl pyruvate over platinum catalysts

Chiral sonochemical hydrogenation of an aliphatic -ketoester, ethyl pyruvate to ethyl lactate was carried out over various platinum catalysts in different solvents under atmospheric hydrogen pressure. The reaction rates and the enantiomeric excesses were determined over Pt/C, Pt/SiO₂ and Pt/K-10 catalysts both under conventional and sonochemical conditions. The effect of ultrasounds on the catalytic activity and enantioselectivity was tested applying sonochemical pretreatment before the reaction. The ultrasonic irradiation was found to be highly advantageous in these hydrogenations. After insonation of the catalysts, the enantioselectivity was highly improved over Pt/SiO₂ and Pt/K-10 catalysts. In addition, the reactions took place in quantitative yield and with complete chemoselectivity and the hydrogenation rates increased with one order of magnitude despite the very mild (atmospheric hydrogen pressure, room temperature) experimental conditions.     

Selective hydrogenation of furfural to furfuryl alcohol over catalysts prepared via sonochemistry

Copper-chromite oxide and TiO2-supported copper-chromite oxide catalysts are prepared by various methods. They are characterized with ICP, BET, XRD, XPS, SEM, and TEM, etc. Their catalytic performance for liquid phase hydrogenation of furfural to furfuryl alcohol is also valuated. The catalysts prepared by ultrasound exhibit good performance. Catalytic activity of TiO2-supported catalysts is higher than that of catalyst without TiO2, notwithstanding they are all prepared by ultrasound. It is worth stressing that after reduced the TiO2-supported catalysts, which are X-ray amorphous, display good performance at 140 degrees C, while the catalysts without TiO2 show no activity under the same condition. Obtained results indicate that the catalytic performance of catalysts depends upon the amount of reducible copper ions and the activity decay is related to the loss of metal elements on the surface of catalyst.     

Ultrasonics in heterogeneous metal catalysis: sonochemical chemo- and enantioselective hydrogenations over supported platinum catalysts

Sonochemical chemo- and enantioselective hydrogenations over supported platinum catalysts are described. We disclose our results with respect to a sonochemical modification of the chemoselective hydrogenation of cinnamaldehyde over supported platinum catalysts, and the asymmetric hydrogenation of ethyl pyruvate promoted by various ultrasonic pretreatments. The ultrasonic pretreatment of the supported platinum catalysts was found to be highly beneficial in almost every case, improving both the catalytic activity and selectivity. The effect of additional experimental variables, such as hydrogen pressure, catalyst support, temperature and the ultrasonic insonation time were also studied. The enantioselectivity of the hydrogenation of ethyl pyruvate increased up to 97.1% ee. In the case of cinnamaldehyde hydrogenation, the selective preparation of cinnamyl alcohol became possible. The theoretical aspects of the working mechanisms in comparison with 'silent' reactions will also be provided.     

利用多元醇共浸渍促进Ni/MCM-41催化剂的萘加氢活性

研究了利用乙二醇、甘油、木糖醇、山梨醇、葡萄糖多元醇共浸渍方法促进Ni负载在MCM-41载体上的萘加氢活性．和传统的浸渍方法比较,只要在硝酸盐的水溶液中添加适合量的多元醇即可以提高金属活性中心和载体表面的相互作用,导致5 nm以下超细NiO粒子的形成,以及高分散的催化活性中心和异常高的催化活性;零价Ni的纳米粒子从36.1 nm减少到5 nm以下,同时萘的加氢活性取决于零价Ni纳米粒子的大小．利用多元醇共浸渍制备的负载型催化剂表现出优异的催化活性,即使在55 oC的低温环境中亦表现出100%的萘转化率．     

活性炭担载的Rh-M0-K合成醇催化剂

采用XRD、EXAFS等技术研究向微量贵金属Rh对活性炭担载的Rh-Mo-K合成醇催化剂结构的影响,并关联其催化性能。氧化态Rh-Mo-K／AC样品中Rh与Mo有着较强的相互作用,使得K2Mo2O7向MoO2转化。硫化还原后,Mo主要以MoS2微晶形式存在,其有序结构尺度随Rh含量的增加而减小。经Rh助剂修饰后,催化剂的合成醇催化性能有明显的提高。