Metal/semiconductor hybrids consisting of self-assembled CdS nanoparticles on Cd nanowires

We report on the synthesis and the characterisation of metal/semiconductor hybrids consisting of self-assembled CdS nanoparticles on Cd nanowires, which are grown by thermal evaporation of the mixture of CdS and Cr. The growth of the hybrids is attributed to the decomposition of CdS at high temperature and the strain relieving that arises mainly from the lattice mismatch between Cd and CdS. Temperature dependence of zero-field resistance of single nanohybrid indicates that the as-produced Cd/CdS nanohybrid undergoes a metal--semiconductor transition as a natural consequence of hybrid from metallic Cd and semiconducting CdS. The metal/semiconductor hybrid property provides a promising basis for the development of novel nanoelectronic devices.     

Ultraviolet emission of ZnO film prepared by electrophoretic deposition

We deposited high quality ZnO film by electrophoretic deposition (EPD) using high quality ZnO powder prepared by solid-state pyrolytic reaction. X-ray photoelectron spectroscopy (XPS) and the infrared (IR) absorption spectrum clearly indicate that the ZnO phase powder has been prepared. Transmission electron microscope (TEM) imaging and x-ray diffraction (XRD) show that the average grain size of the powder is about 20nm. XRD and selected-area electron diffraction (SAED) reveal that the ZnO film has a polycrystalline hexagonal wurtzite structure. Only a strong ultraviolet emission peak at 390nm can be observed at room temperature.     

Nonpolar a-plane light-emitting diode with an in-situ SiNx interlayer on r-plane sapphire grown by metal-organic chemical vapour deposition

We report on the growth and fabrication of nonpolar a-plane light emitting diodes with an in-situ SiN_x interlayer grown between the undoped a-plane GaN buffer and Si-doped GaN layer. X-ray diffraction shows that the crystalline quality of the GaN buffer layer is greatly improved with the introduction of the SiN_x interlayer. The electrical properties are also improved. For example, electron mobility and sheet resistance are reduced from high resistance to 31.6 cm²/(V·s) and 460 Ω/口 respectively. Owing to the significant effect of the SiN_x interlayer, a-plane LEDs are realized. Electroluminescence of a nonpolar a-plane light-emitting diode with a wavelength of 488nm is demonstrated. The emission peak remains constant when the injection current increases to over 20 mA.     

Characterization of relativistic electrons generated by a cone guiding laser pulse

We demonstrated the interaction of a gold cone target with a femto second(fs) laser pulse above the relativistic intensity of 1.37×10 18 μm 2 W/cm 2.Relativistic electrons with energy above 2 MeV were observed.A 25%-40% increase of the electron temperature is achieved compared to the case when a plane gold target is used.The electron temperature increase results from the guiding of the laser beam at the tip and the intense quasistatic magnetic field in the cone geometry.The behavior of the relativistic electrons is verified in our 2D-PIC simulations.     

纳米Pd和Au催化CO2还原粒径效应的密度泛函理论计算研究

以可再生能源为能量来源,在水溶液中进行的光(电)催化CO2还原生成高附加值化学品和燃料是解决能源危机与环境污染的有效途径之一.CO是一种简单却很重要的CO2还原产物,它可以作为水煤气变换反应与费托合成的重要原料.具有较高CO选择性的贵金属纳米颗粒催化剂(如Au和Pd)一直受到研究者的广泛关注.一般来说,金属颗粒催化剂的...     

Support stabilized PtCu single-atom alloys for propane dehydrogenation

PtCu single-atom alloys (SAAs) open an extensive prospect for heterogeneous catalysis. However, as the host of SAAs, Cu suffers from severe sintering at elevated temperature, resulting in poor stability of catalysts. This paper describes the suppression of the agglomeration of Cu nanoparticles under high temperature conditions using copper phyllosilicate (CuSiO₃) as the support of PtCu SAAs. Based on quasi in situ XPS, in situ CO-DRIFTS, in situ Raman spectroscopy and in situ XRD, we demonstrated that the interfacial Cu⁺–O–Si formed upon reduction at 680 °C serves as the adhesive between Cu nanoparticles and the silicon dioxide matrix, strengthening the metal–support interaction. Consequently, the resistance to sintering of PtCu SAAs was improved, leading to high catalytic stability during propane dehydrogenation without sacrificing conversion and selectivity. The optimized PtCu SAA catalyst achieved more than 42% propane conversion and 93% propylene selectivity at 580 °C for at least 30 hours. It paves a way for the design and development of highly active supported single-atom alloy catalysts with excellent thermal stability.

This paper describes PtCu single-atom alloys supported on copper phyllosilicate via Cu⁺–O–Si. The catalyst exhibits sintering resistance in propane dehydrogenation reaction without sacrificing activity and selectivity.     

Active sites in CO2 hydrogenation over confined VOx-Rh catalysts

Science China Chemistry - Metal oxide-promoted Rh-based catalysts have been widely used for CO2 hydrogenation, especially for the ethanol synthesis. However, this reaction usually suffers low CO2...     

继承的一个数学模型

提出了继承的一个数学模型,引入图序类别型构用来表示面向对象语言中程序的代数结构,将继承的形式语义刻划为图序类别型构集上的延拓函数。通过该数学模型,程序之代数结构的性质能反映语言的语法约束,延拓函数的性质能揭示语言中继承的特点.     

Observation of Radial Propagation of Electrostatic Fluctuations in Edge Plasma of the Sino United Spherical Tokamak

Radial propagation of electrostatic fluctuations in the edge plasma of Sino-United Spherical Tokamak (SUNIST) has been measured using Langmuir probes. The propagation characteristics of the floating potential fluctuations are analysed by the two-point correlation technique. The results show radially outward propagation of the turbulent fluctuations at all measured radial positions. The power-average wavenumber profile is approximately constant in plasma edge region and suddenly increases to the limiter. These results are in good agreement with the model predictions proposed by Mattor which suggests that the drift wave propagation may be a source of edge turbulence.     

Rh（100表面乙醇吸附与分解的HREELS研究

利用热脱附谱和高分辨能量损失谱技术研究了乙醇在Ｒｈ（１００）表面的吸会和分解过程，结果表明，１３０时Ｒｈ（１００）面暴露乙醇，表面首先形成化学附层，随乙醇暴露增加，表面出现多层凝聚态，表面升温至１５０Ｋ，吸附乙醇从Ｒｈ（１００）表面脱附，同时部分化学吸附乙醇分子发生羟基断裂，生成表面乙氧基，进一步升谩，表面乙氧基脱氢分解，其分解的主要途径是发生甲基脱氧，β－Ｃ与表面发生作用，生成一种含氧的金属有机