Mechanism of doping gallium arsenide with carbon tetrachloride during organometallic vapor-phase epitaxy

The rates of decomposition of carbon tetrachloride (CCl₄), triethylgallium (TEGa), and tertiarybutylarsine (TBAs), and the rate of GaAs film growth, were measured as a function of the process conditions during organometallic vapor phase epitaxy. In addition, the reaction of CCl₄ with the GaAs(001) surface was monitored in ultrahigh vacuum using infrared spectroscopy, temperature-programmed desorption, and scanning tunneling microscopy. These experiments have revealed that CCl₄ adsorbs onto Ga sites, and decomposes by transferring chlorine ligands to other Ga atoms on the surface. Chlorine and gallium desorb from the surface as GaCl, while the carbon incorporates into the lattice. Triethylgallium is consumed by two competing reactions: GaAs film growth and GaCl etching. Depending on the V/III and IV/III ratios and temperature, the etch rate can be high enough to prevent any GaAs deposition.     

Two Sides of the Page: The Antifact and the Artefact

For Bryan Cantley technology has introduced new possibilities for drawing with ‘the ability to render conditions of transformation, phase shifting, entropy and revolution’. It has also prompted a rethink of the phenomenological relationship of architectural drawing with the world; between the page and objects; between the antifact and the artefact. He makes an analogy between the legal status of the unborn child and nascent, unbuilt drawn architecture.     

叔胺在高岭石（001）面吸附的分子动力学模拟

三种叔胺（DRN,DEN,DPN）对高岭石的捕收能力顺序为：DEN〉DPN〉DRN。Zeta 电位测试表明,这三种叔胺能显著增大高岭石的表面电位,对表面电位的增大同样遵循顺序：DEN〉DPN〉DRN。分子动力学模拟研究表明,叔胺阳离子在吸附到高岭石（001）面的过程中,N 原子上所连接的取代基的空间形状发生了偏转或扭曲,相关键角发生了变化。结合量子化学计算结果进行综合计算可知,这三种叔胺阳离子与高岭石 4×4×3 的（001）面的库仑静电力分别为：1.38×10-7 N （DRN12H＋）,1.44×10-6 N （DEN12H＋）,1.383×10-6N（DPN12H＋）。     

木醋杆菌的培养基优化研究

采用六因素三水平正交实验对木醋杆菌Acetobacter xylinum HN001的培养基进行了优化,确定了最佳培养基组成为:葡萄糖30 g/L,蛋白胨7.5 g/L,酵母粉10 g/L,磷酸氢二钠7.5 g/L,柠檬酸0.5 g/L,pH 5.0,30℃。采用优化的培养基制备细菌纤维素,应用傅立叶红外光谱、热重分析和扫描电子显微镜对其结构和性能进行表征。红外光谱测试显示含有纤维素的特征吸收峰。热重分析结果表明细菌纤维素最大失重温度为319.06℃,热稳定性较好。扫描电镜观察到细菌纤维素的纳米网状结构。     

{001}面TiO2光催化降解罗丹明B的研究

以钛酸四丁酯为钛源、HF为形貌控制剂,采用水热法在不同反应温度条件下制备纳米片状{001}面TiO2,并以罗丹明B的光催化降解为模型反应,考察了不同反应温度对{001}面TiO2形貌结构的影响,研究了反应温度、pH及催化剂投加量对光催化活性的影响。结果表明,所有{001}面TiO2均具有良好的锐钛矿相衍射峰,并且在紫外光区域具有明显的光吸收;当反应温度为180℃、溶液pH为2、投加量为1 g/L时,样品对罗丹明B光催化降解活性最高,紫外光照射20 min后罗丹明B降解率可达100%。     

Morphology control and phase transition of hexagonal sodium niobate particles

Hexagonal NaNbO₃ particles with an ilmenite structure and plate-like morphology were synthesized by a hydrothermal method. The morphological evolution of the solid products with the increasing mineralizer concentration was monitored via SEM during the hydrothermal reaction. By carefully controlling the mineralizer concentration, particles with a diameter of 10–60 µm and a thickness of 1–10 µm were obtained. The particles were transformed from the ilmenite structure into the perovskite structure during the thermal treatment at 600 °C. Their plate-like morphology was maintained with some cracking on the surface. The surface orientation of the perovskite particles was micro- and macroscopically characterized by EBSD and XRD analysis, respectively. The results indicate that thinner particles tend to be more oriented in the (00 l) crystal planes.     

鄂尔多斯盆地西南部上古生界致密砂岩中碳酸盐胶结物特征及成因

在盆地内部钻井岩心与盆地西南缘野外露头观察基础上,综合运用薄片鉴定、扫描电镜、电子探针、微区碳氧同位素、流体包裹体均一温度与激光拉曼成分分析,开展了鄂尔多斯盆地西南部上古生界盒8段致密砂岩储层中碳酸盐胶结的成因机制研究。结果显示,盒8段致密砂岩储层中存在4期碳酸盐胶结：①同生成岩阶段碳酸盐胶结物形成于烃类充注之前,直接从碳酸盐过饱和的沉积水中析出;②早成岩阶段B期和中成岩阶段A期的碳酸盐胶结物与烃源岩中生烃、排烃提供的有机碳源有关;③盆地抬升阶段形成的碳酸盐胶结物受到大气降水等无机碳源的影响。盆地西南缘盒8段储层中的烃类充注始于烃源岩演化早期（80 ℃左右）,在早成岩阶段B期就形成了规模较大的有机碳源成因的碳酸盐胶结物;盆地内部规模较大的烃类充注发生在烃源岩成熟之后（120 ℃左右）,有机碳源成因的碳酸盐胶结物主要形成于中成岩阶段A期。     

Serpin多抗制备和产Serpin的双歧杆菌菌株的初步筛选

从长双歧杆菌WBL001基因组中克隆了serpin基因,构建重组Serpin蛋白的原核表达体系pBX2-serpin,纯化表达产物作为抗原,免疫小鼠制备Serpin的多克隆抗体.采用偶联Serpin的磁珠纯化多克隆抗体,并探究了不同溶剂对抗体洗脱效率的影响.纯化的多抗用于斑点杂交筛选产Serpin蛋白的菌株.结果表明:磁珠纯化多克隆抗体以1 mol/L NaOH的洗脱率最高,达50％;纯化后的Serpin抗体消除了与部分乳酸菌和致病菌的非特异性反应;采用斑点杂交方法从11株双歧杆菌中筛选到婴儿双歧杆菌WBAN07具有类Serpin蛋白.     

具有高活性(001)晶面的TiO2纳米方块的制备及光催化性能

采用水热法制备了尺寸为70~100 nm, 具有高活性(001)晶面的锐钛矿相TiO₂纳米方块, 利用FE-SEM、TEM、XRD和UV-Vis DRS等手段对催化剂结构和光吸收性能进行分析, 同时考察了水热反应温度和溶液pH对TiO₂形貌和(001)晶面暴露率的影响。以酸性红染料为目标污染物, 对催化剂的光催化活性进行研究。实验结果表明, 合成TiO₂纳米方块的最佳条件为水热温度180℃、溶液pH=4~5。(001)晶面的光催化活性优于(101)晶面, 具有33%(001)晶面暴露率的TiO₂纳米方块的光催化活性是普通TiO₂的1.6倍。     

快速率生长MBE InAs/GaAs(001)量子点

用快速率(1.0ML/s)生长MBE InAs/GaAs(001)量子点。原子力显微镜观察结果表明,在量子点体系形成的较早阶段,量子点密度N(θ)随InAs沉积量θ的变化符合自然指数形式N(θ)∝ek(θ-θc),这与以前在慢速生长(≤0.1ML/s)条件下出现的标度规律N(θ)∝(θ-θc)α明显不同。另外,在N(θ)随θ增加的过程中,快速率生长量子点的高度分布没有经历量子点平均高度随沉积量θ逐渐增加的过程。这些实验观察说明,以原子在生长表面作扩散运动为基础的生长动力学理论至少是不全面的,不适用于解释InAs量子点的形成。这些观察和讨论说明,即使在1.0ML/s的快速率生长条件下,量子点密度也可以通过InAs沉积量有效地控制在1.0×108cm-2以下,实现低密度InAs量子点体系的制备。