Photocatalytic Synthesis of Oxygenates from Gaseous CO2 and CH4 over Semiconductor

Photoinduced synthesis of CO2 and CH4 was investigated using a batch reaction system on several photoactive materials supported on silicon dioxide. Single semiconductor showed higher selectivity to C1 compounds. The production of C2-C3 oxygenates took place preferentially on composite semiconductor photocatalysts. In particular, it was found that acetone was the primary product over Cu/CdS-TiO2/SiO2.     

中晚期高危妊娠引产32例分析及经验总结

目的：分析中晚期妊娠合并症引产病例的特征，适当引产方式的选择。总结引产处理成功的经验。方法：总结32例中晚期妊娠合并内外科疾病选择引产病例，分析各病种分布以及引产方式、引产并发症。结果：32例病例中肝肾疾病占31％，选择利凡诺引产15例，水囊引产12例，药物引产4例。均无内外科并发症发生。结论：做好有妊娠合并症的中晚期引产的术前术中准备工作，选择合适的引产方式是引产成功安全的关键。     

非有效市场条件下证券交易税实证研究

主要分析在股市存在泡沫的情况下,证券交易税税率提高对采取正反馈投资策略的噪音交易者和理性投资的被动交易者及套利者的影响,在理论不支持征收交易税降低市场波动的宏观调节政策.     

Effect of nonstoichiometry on Raman scattering of VO2 films

We report on Raman scattering of VO2 films prepared by radio frequency magnetron sputtering under different conditions. Our investigations revealed that the dominated Raman peaks shift towards high frequency for both V-rich and O-rich VO2 films, compared with the stoichiometry VO2 films. The experimental evidence is presented and the cause for nonstoichiometry dependence of Raman spectra of VO2 films is discussed.     

光电效应演示实验方法的探讨

1 引言 光电效应演示实验是普物的重要实验,但按紫外线照射锌板的方法难以成功,其原因为     

Cu-MgF2复合纳米金属陶瓷薄膜的电导特性研究

用射频磁控共溅射法制备了Cu体积分数分别为 10 % ,15 % ,2 0 %和 3 0 %的Cu MgF2 复合金属陶瓷薄膜 .用x射线衍射、x射线光电子能谱和变温四引线技术对薄膜的微结构、组分及电导特性进行了测试分析 .微结构分析表明 :制备的Cu MgF2 复合薄膜由fcc Cu晶态纳米微粒镶嵌于主要为非晶态的MgF2 陶瓷基体中构成 ,Cu晶粒的平均晶粒尺寸随组分增加从 11 9nm增至 17 8nm .5 0— 3 0 0K温度范围内的电导测试结果表明 :当Cu体积分数qM 由 15 %增加到 2 0 %时 ,Cu MgF2 复合薄膜的电阻减小了 8个量级 ,得出制备的复合薄膜渗透阈qCM 应处于 15 %和 2 0 %之间 .qM 在 10 %和 15 %之间的薄膜呈介质导电状态 ,而在 2 0 %和 3 0 %之间的薄膜则呈金属导电状态 .从理论上讨论了复合薄膜中杂质电导和本征电导的激活能及其对电导的贡献 ,并讨论了Cu MgF2 复合纳米金属陶瓷薄膜的渗透阈 ,得到了和实验一致的结果     

Synthesis of side‐chain liquid‐crystalline homopolymers and triblock copolymers with p‐methoxyazobenzene moieties and poly(ethylene glycol) as coil segments by atom transfer radical polymerization and their thermotropic phase behavior

A series of side‐chain liquid‐crystalline (LC) homopolymers of poly[6‐(4‐methoxy‐4′‐oxy‐azobenzene) hexyl methacrylate] with different degrees of polymerization were synthesized by atom transfer radical polymerization (ATRP), which were prepared with a wide range of number‐average molecular weights from 5.1 × 10³ to 20.6 × 10³ with narrow polydispersities of around 1.17. Thermal investigation showed that the homopolymers exhibit two mesophases, a smectic phase, and a nematic phase, and the phase‐transition temperatures of the homopolymers increase clearly with increasing molecular weights. A series of novel LC coil triblock copolymers with narrow polydispersities was synthesized by ATRP, and their thermotropic phase behavior was investigated with differential scanning calorimetry and polarized optical microscopy. The LC coil triblocks were designed to have an LC conformation of poly[6‐(4‐methoxy‐4′‐oxy‐azobenzene) hexyl methacrylate] with a wide range of molecular weights from 3.5 × 10³ to 1.7 × 10⁴ and the coil conformation of poly(ethylene glycol) (PEG) (number‐average molecular weight: 6000 or 12,000) segment. Their characterization was investigated with ¹H NMR, Fourier transform infrared spectra, and gel permeation chromatography. Triblock copolymers exhibited a crystalline phase, a smectic phase, and a nematic phase. The phase‐transition temperatures from the smectic to nematic phase and from the nematic to isotropic phase increased, and the crystallization of PEG depressed with increasing molecular weight of the LC block. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2854–2864, 2003     

Yb2.75C60价带光电子能谱

用角积分紫外光电子能谱技术测量了Yb2 75C6 0 薄膜的价带电子态密度分布 .相纯Yb2 75C6 0 样品通过C1s芯态x射线电子谱峰的位移表征 .结果表明Yb2 75C6 0 是半导体 ,在费米能级处几乎没有电子态分布 .Yb 6s电子态和C6 0 LU MO能带的杂化效应不可忽略 ,有部分Yb 6s电子分布在Yb C6 0 杂化能带上 .     

A Mossbauer study of the magnetic coupling in iron phosphorous trisulfides

The polycrystalline sample of layered compound FePS_3 has been investigated by using M?ssbauer spectroscopy (12K to 300K), magnetic susceptibility measurements, x-ray diffraction and FTIR spectroscopy. The antiferromagnetic order exists below T_N=120.5±1K. The M?ssbauer spectra below T_N indicate that the magnetization axis is perpendicular to the layer of FePS_3, and the divalent iron cations are in their high spin configurations. By fitting the hyperfine field parameters near the Néel temperature, we obtain information on the nature of magnetic interactions in the material. The results show that the magnetic coupling can be treated by the two-dimensional Ising model, and it can be interpreted on the basis of a crystal-field effect.     

35Cr25Ni12奥氏体耐热钢中碳化物的电子显微分析

应用扫描电镜（SEM）和透射电镜（TEM）研究了长期使用前后的35Cr25Ni12奥氏体耐热钢中的碳化物演变行为；该钢固溶时效后的组织由初晶奥氏体及M23C6共晶碳化物组成，奥氏体基体中析出了二次M23C6，二次碳化物总是与基体保持立方－立方取向关系；长期使用（3、5年）后，奥氏体中析出的二次碳化物量明显增加，部分M23C6已转变为M6C，M6C与奥氏体基体以及二次碳化物M23C6保持[001]M6C//[221]A//[221]M23C6孪晶取向关系。