Growth of oxide thin films for optical gas sensor applications

Tungsten trioxide and titanium dioxide thin films were synthesised by pulsed laser deposition. We used for irradiations of oxide targets an UV KrF* (λ = 248 nm, τ_FWHM ≅ 20 ns, ν = 2 Hz) excimer laser source, at 2 J/cm² incident fluence value. The experiments were performed in low oxygen pressure. The (0 0 1) SiO₂ substrates were heated during the thin film deposition process at temperature values within the 300-500 °C range. The structure and crystalline status of the obtained oxide thin films were investigated by high resolution transmission electron microscopy. Our analyses show that the films are composed by nanoparticles with average diameters from a few to a few tens of nm. Moreover, the films deposited at substrate temperatures higher than 300 °C are crystalline. The tungsten trioxide films consist of a mixture of triclinic and monoclinic phases, while the titanium dioxide films structure corresponds to the tetragonal anatase phase. The oxide films average transmittance in the visible-infrared spectral range is higher than 80%, which makes them suitable for sensor applications.     

A testbench for the nested dipole hypothesis of Kosterlitz and Thouless

We consider the two-dimensional one-component plasma without a background and confined to a half-plane near a metal wall. The particles are also subjected to an external potential acting perpendicular to the wall with an inverse-power-law Boltzmann factor. The model has a known solvable isotherm which exhibits a Kosterlitz-Thouless-type transition from a conductive to an insulator phase as the power law is varied. This allows predictions of theoretical methods of analyzing the Kosterlitz-Thouless transition to be compared with the exact solution. In particular, we calculate the asymptotic density profile by resumming its low-fugacity expansion near the zero-density critical coupling in the insulator phase, and solving a mean-field equation deduced from the first BGY equation. Agreement with the exact solution is obtained. As the former calculation makes essential use of the nested dipole hypothesis of Kosterlitz and Thouless, the validity of this hypothesis is explicitly verified.     

Superdegenerate point in FCC phase diagram: CVM and Monte Carlo investigations

We investigate the topology of the phase diagram of binary alloys on the fee lattice with first-neighbor antiferromagnetic interactions around the superdegenerate point, where the L1₀ and L1₂ phases meet. We treat the system as a hard-constraint lattice gas, following a procedure previously described by Lebowitzet al. We perform cluster variation method calculations in theT0 limit and Monte Carlo simulations directly atT=0 K on the ground states of the superdegenerate point. We find that: (i) there is no disordered phase in the neighborhood of this point; (ii) a phase L for which two of the four cubic sublattices have the same average occupancy and each of the two others are different appears between L1₀ and L1₂; (iii) the transition L/L1₂ is of first order.     

顶空气相色谱法测定延生护宝液中甲醇残留量

本文用顶空气相色谱法，以ＧＤＸ－１０１为固定相，测定了延生护宝液中甲醇残留量，方法的回收率在８５．９％－１０１．６％之间，变异系数０．３％，最小检出量１．０ｍｇ／Ｌ。     

兖州高硫煤的加氢热解脱硫及脱硫动力学

在加压热天平上，考察了氢气和氮扬气氛下高硫煤的热解脱硫。利用气相色谱在线分析研究了硫化氢氢气的逸出规律。结果表明，加氢热解比氮气下的热解有着更显著的脱友作用，脱硫率可达９０％以上。而且加氢热解下６５％的脱除硫转化为气相硫化氢，而氮气下热解是有８０％的硫转化为液相。     

天然气和氧偶联制环氧乙烷催化剂的反应性能

研制了天然气和氧经偶联反应制环氧乙烷的Ａｇ－Ｂａ－Ｃｓ／Ａｌ２Ｏ３催化剂（ＮＥＯ－１）。用Ｎ２＋Ｏ２＋Ｃ２Ｈ４和偶联产物气加氧作原料气，在２５０℃，空速２５００ｈ＾－１时，乙烯转化率和ＥＯ选择性分别达到了３０％和８０％，ＮＥＯ－１催化具有适宜的比表面和孔结构，用ＸＰＳ分析发现，与新鲜的催化相比，经活化和反应后的催化剂表面的Ｂａ，Ｃｓ原子浓度增高，并具有较多的吸附氧物种。     

铁(Ⅲ)-邻菲罗啉溶液体系的光化学还原 Ⅱ.气相色谱法研究光化反应机理

关于Fe(Ⅲ)-邻菲罗啉(phen)溶液的光化学还原现象的记载可追溯到十九世纪末。     

纳米氧化铜的制备及常温脱硫效能研究

采用硝酸铜为原料、氢氧化钠溶液为沉淀剂、使用体积比为1∶1的乙醇-水溶液为分散剂的直接沉淀法制备，通过改变工艺条件得到了三种纳米氧化铜产品，平均粒径分别为25.63，10.74和7.57 nm。采用TG-DTA、FIR、XRD和TEM等对纳米氧化铜进行表征。对产品的常温脱硫活性进行了穿透试验，并与已开发的其他常温精脱硫产品进行了比较，结果表明纳米氧化铜应用于H₂S脱硫，可在常温条件下具有优异的脱硫活性，对H₂S的脱除精度可以达到0.05 mg·m^-3以下。经过优选，产品在3 000 h^-1空速下穿透硫容达到25.3%，高于同类型的其他脱硫剂产品。