Adsorption and decomposition of H2S on Pd(1 1 1) surface: a first-principles study

Gradient-corrected density functional theory was used to investigate the adsorption of H₂S on Pd(1 1 1) surface. Molecular adsorption was found to be stable with H₂S binding preferentially at top sites. In addition, the adsorption of other S moieties (SH and S) was investigated. SH and S were found to be preferentially bind at the bridge and fcc sites, respectively. The reaction pathways and energy profiles for H₂S decomposition giving rise to adsorbed S and H were determined. Both H₂S_(ad) → SH_(ad) + H_(ad) and SH_(ad) → S_(ad) + H_(ad) reactions were found to have low barriers and high exothermicities. This reveals that the decomposition of H₂S on Pd(1 1 1) surface is a facile process.     

Bulk growth of Hg0.8Cd0.2Te single crystals by a combined CVT-seeding technique

The growth of high quality Hg_0.8Cd_0.2Te bulk single crystals by CVT, combined with an in-situ seeding technique, is reported here for the first time. For this purpose, a temperature difference of 590° → 540° C with a gradient of 40°-50° C/cm at the solid-vapor interface, and about 0.1 atm of HgI₂ as a transport agent, were employed. The bulk crystals have the expected stoichiometry and compositional homogeneity. Etch pit densities of 10⁴-10⁵ cm⁻² on the (111) face and hitherto unreported etch pits on the (100) face were observed in this work. Possible origins of the sub-grain structure are discussed.     

Nd3+ Doped Silicate Glass Photonic Crystal Fiber with Random Hole Distributions

The fabrication of one kind of large core area Nd3 doped silicate glass photonic crystal fiber, and demonstration of the fiber's waveguidence properties were reported. This fiber owns a random air hole distribution in the cladding. The measured minimum loss of this kind of fiber is 10 dB·m-1 at 660 nm. These fibers can sustain only a single mode at least over wavelength ranging from 660 nm to 980 nm.     

Temperature Dependence of the Raman Spectrum in Lithium Oxide Single Crystal

Temperature dependence of the Raman spectrum of lithium oxide single crystal has been measured over a temperature range of 80 to 1073 K. The frequency shift and the line width of the Raman spectrum in lithium oxide were about 531 and 4.5 cm^-1 at 80 K, respectively. At 1073 K, the frequency shift and the line width attained the values of 464 and 112 cm^-1, respectively. The strong temperature dependence of the frequency shift and line width was compared with data from some crystals with a fluorite structure.     

手持式GPS测量在地球化学勘查中的应用

在大比例尺的化探测量中，用GPS单点绝对定点技术来进行测网的布设，减少了控制测量环节。降低了生产成本。因此，GPS绝对定点在化探测量中仍有应用的前景。但是，绝对定位时必须做到：(1)合理选择校正的控制点(三角点或四角点)；(2)正确校正参数；(3)定期地检测仪器；(4)保证仪器的高度角和有效工作时间。本次该方法应用在化探的测网布设中。实测面积7km^2，经传统测量仪器检查验收，证明文中提出的方案完全可以用于生产实践。     

单相多极开关磁阻发电机设计及性能仿真

分析中低速开关磁阻发电机运行及控制特点，提出一种基于准线性模型的设计方案和步骤，该方法克服了类比法的盲目性。编制了计算机设计仿真程序，给出了一台样机的设计结果和仿真曲线，结果表明方法合理，具备一定的精度，能满足工程设计的要求。     

单孔护壁爆破数值模拟

运用LS-DYNA软件对单孔护壁爆破和切缝药包爆破进行了三维数值模拟,结果显示,由于PVC-U套管的存在,作用于孔壁的爆炸应力波峰值被显著削弱,降低率达到30%～46%,并推迟了其到达保留岩体孔壁时间.与传统的切缝药包爆破相比,保留岩体损伤更小.     

电话防盗报警器

详细介绍了电话通讯技术以及安全报警技术的应用，二者如何有效地结合起来形成综合联网报警系统。分析了HT9200A和MT8870DC的电路结构，及与AT89C51的接口电路。