环氧氯丙烷成胶法制备磷酸盐及其催化性质

对环氧氯丙烷成胶法等技术制备的金属磷酸盐进行了研究,对所制备的一系列磷酸盐用BET、XRD、IR和TG-DTA表征,比较了它们在催化反应中的酸性.结果表明,环氧氯丙烷成胶法制备得到的鳞石英型结构磷酸铝具有较强的酸性;而对于Fe3+、Ca2+,只得到相应的比表面积较小的偏磷酸盐结构化合物.     

α-β石英相变的应变参数计算及其地质意义

 利用已有的α和β石英压缩性、热膨胀性、弹性及相变温度压力资料，计算了α-β石英相转变时，α和β石英的晶胞参数。依据虎克定律以及高压下β石英的弹性参数，估算了α-β石英相转变时的应变、应力和应变能。结果表明，在0~1.1 GPa条件下，随压力升高，α-β石英相变的线应变介于-0.006~0.005之间，体应变介于-0.016~0.012之间，应力介于-0.46~0.14 GPa之间；应变能介于965~2 760 kJ/m³之间。压力为0.5 GPa左右时，α-β石英相变的应变、应力和应变能均达到最小值。在此基础上，讨论了壳内大规模酸性岩浆活动引起的α-β石英相变对壳内岩石的作用。     

Growth of Silicon Nanowires by Heating Si substrate

Amorphous silicon nanowires were prepared by heating an Si substrate at high temperatures using an Ni (or Au) catalyst.The nanowires have a diameter of 10-40nm and a length of up to several tens of micrometres.Unlike the well-known vapour-liquid-solid mechanism,a solid-liquid-solid mechanism appeared to control the nanowire growth.The heating process had a strong influence on the growth of silicon nanowires.It was found that ambient gas was necessary to grow nanowires.This method can be used to prepare other kinds of nanowires.     

The influence of SiNx substrate on crystallinity of μc-Si film used in thin film transistors

This paper found that the crystalline volume ratio （Xc） of μc-Si deposited on SiNx substrate is higher than that on 7059 glass. At the same silane concentration （SC） （for example, at SC=2%）, the Xc of μc-Si deposited on SiNx is more than 64%, but just 44% if deposited on Conning 7059. It considered that the ‘hills＇ on SiNx substrate would promote the crystalline growth of μc-Si thin film, which has been confirmed by atomic force microscope （AFM） observation. Comparing several thin film transistor （TFT） samples whose active-layer were deposited under various SC, this paper found that the appropriate SC for the μc-Si thin film used in TFT as active layer should be more than 2%, and Xc should be around 50%. Additionally, the stability comparison of μc-Si TFT and a-Si TFT is shown in this paper.     

Measurement of Mg Content in Zn1-xMgxO Films by Electron Probe Microanalysis

Zn1-xMgxO films are grown on A-sapphire substrates by molecular beam epitaxy, and Mg content in the Zn1-xMgxO films is measured by electron probe microanalysis （EPMA） when the acceleration voltage, the emission current, and the magnification are set to be 1 k V, 30 μA and 1000, respectively. The dead time is controlled within 17%-20% during the measurement with the receive angle of characteristic x-ray of 45°. The Mg content of the ZnMgO film is calculated by the low energy calibration and the ZAF calibration. By comparing the measurement result with the theoretical analysis and the EPMA result with the inductively coupled plasma （ICP）, one can obtain that the measured value of Mg content of the samples is in good agreement with the theoretical analysis no matter whether the phase separation exists or not, and the correctness of ICP and EPMA is valid when Mg content in the samples is less than 0.5.     

Luminescent Characteristics of Near Ultraviolet InGaN/GaN MQWs Grown on Grooved Sapphire Substrates Fabricated by Wet Chemical Etching

InGaN/GaN multiple quantum wells （MQWs） are grown on planar and maskless periodically grooved sapphires by metal organic vapour phase epitaxy （MOCVD）. High-resolution x-ray rocking curves and transmission electron microscopy （TEM） are adopted to characterize the film quality. Compared with the MQWs grown on planar sapphire, the sample grown on grooved sapphire shows better crystalline quality： a remarkable reduction of dislocation densities is achieved. Meanwhile, the MQWs grown on grooved sapphire show two times larger PL intensity at room temperature. Temperature-dependent PL measurements are adopted to investigate the luminescence properties. The luminescence thermal quenching based on a fit to the Arrhenius plot of the normalized integrated PL intensity over the measured temperature range suggests that the nonradiative recombination centres （NRCs） are greatly reduced for the sample grown on grooved sapphire. We assume that the reduction of dislocations which act as NRCs is the main reason for the sample grown on pattern sapphire having higher PL intensity.     

GaN衬底材料LiGaO2晶体的温度梯度法生长及分析

以温度梯度法生产LiGaO2晶体，通过形貌观察、X射线衍射分析和X射线光电子能谱分析确认在样品的中部形成了单一相的LiGaO2晶体。但在生长过程中由于CO气体的存在，熔体表面形成了LiO-和金属态的Ga,钼坩埚被侵蚀形成Li2MoO4进入熔体，使样品上下两部分的结晶质量变差。     

Quantum Fluctuations of Current and Voltage for Mesoscopic Quartz Piezoelectric Crystal at Finite Temperature

The mesoscopic quartz piezoelectric crystal equivalent circuit is quantized by the method of damped harmonic oscillator quantization. It is shown that the quantum fluctuations of voltage and current of each loop are related to not only the equivalent circuit inherent parameter and squeezing parameter, but also the temperature, and decay according to exponent along with time in the thermal vacuum state, the thermal coherent state and the thermal squeezed state.     

Si衬底GaN基LED的结温特性

结温是发光二极管的重要参数之一,它对器件的内量子效率、输出功率、可靠性及LED的其他一些性能有很大的影响。首次报道Si衬底GaN基LED的结温特性。利用正向压降法测量Si衬底上GaN基LED的结温,通过与蓝宝石衬底上GaNLED的结温比较,发现Si衬底GaNLED有更低的结温,原因归结为Si有更好的导热性。同时也表明:用Si作GaNLED的衬底在大功率LED方面具有更大的应用潜力。     

新疆白干湖与浅成斑岩有关的石英脉型金矿床

白干湖金矿床是近年来西安工程学院发现的重要金矿床之一。该矿床属于与浅成斑岩有关的石英脉型金矿床。含金石英脉体产出于石英斑岩与灰岩的接触带，成矿物质主要来自石英斑岩围岩；流体萃取周围介质中的成矿元素，集中于接触带中，金富集沉淀成矿。矿床形成分热液成矿期和表生氧化期，其中热液成矿期又分黄铁矿－毒砂－石英阶段、金－黝铜矿－方铅矿－闪锌矿－石英阶段、石英－碳酸盐阶段。