Surface rumpling of cubic CaTiO3 from density functional theory

In this paper, the structure of cubic CaTiO3 （001） surfaces with CaO and TiO2 terminations has been studied from density functional calculations. It has been found that the Ca atom has the largest relaxation for both kinds of terminations, and the rumpling of the CaO-terminated surface is much larger than that of TiO2-terminated surface. Also we have found that the metal atom relaxes much more prominently than the O atom does in each layer. The CaO-terminated surface is slightly more energetically favourahle than the TiO2-terminated surface from the analysis of the calculated surface energy.     

Deposition of Cu seed layer film by supercritical fluid deposition for advanced interconnects

The deposition of a Cu seed layer film is investigated by supercritical fluid deposition(SCFD) using H2 as a reducing agent for Bis(2,2,6,6-tetramethyl-3,5-heptanedionato) copper in supercritical CO2(scCO2).The effects of deposition temperature,precursor,and H2 concentration are investigated to optimize Cu deposition.Continuous metallic Cu films are deposited on Ru substrates at 190℃ when a 0.002 mol/L Cu precursor is introduced with 0.75 mol/L H2.A Cu precursor concentration higher than 0.002 mol/L is found to have negative effects on the surface qualities of Cu films.For a H2 concentration above 0.56 mol/L,the root-mean-square(RMS) roughness of a Cu film decreases as the H2 concentration increases.Finally,a 20-nm thick Cu film with a smooth surface,which is required as a seed layer in advanced interconnects,is successfully deposited at a high H2 concentration(0.75 mol/L).     

辽西虹螺山—五指山地区钼多金属矿床控矿条件分析及成矿预测

虹螺山—五指山是辽西重要的钼、铅、锌、金等多金属成矿带,已发现大、中型钼、铅、锌、金矿床多处。文中通过对区内地质背景、典型矿床特征和成矿机制的研究,确定研究区的矿床控矿条件,进行找矿靶区优选。研究认为,研究区地层控矿表现为中元古界、寒武系和奥陶系地层中的各种灰岩、白云岩对矽卡岩型、热液充填交代矿床的控制;岩浆控矿表现为燕山早期岩浆活动为成矿提供热源和部分物质来源;构造控矿表现为多组构造交汇处及多期活动复式构造带为成矿提供了通道和空间。依据研究成果,结合地球化学异常等找矿标志,将杨家杖子外围、八家子外围、旧门、乔杖子划为找矿靶区,可优先安排地质工作。     

β-苯胺基丙烯醛缩苯胺的简便合成

以丙炔醇为原料，经三氧化铬氧化生成丙炔醛后，直接与苯胺反应简便地合成了β-苯胺基丙烯醛缩苯胺．通过正交实验的方法优化了反应条件，得出最佳反应条件为：6．3mL（0．10mol）丙炔醇中加入8．5g（0．085mol）三氧化铬的硫酸水溶液，氧化反应2h后，有机相在冰浴（200mL）冷却下再与25mL（0．25mol）苯胺和63mL 10％盐酸反应得到β-苯胺基丙烯醛缩苯胺盐酸盐，收率为48．4％．将该盐酸盐溶于甲醇与氢氧化钠溶液作用得β-苯胺基丙烯醛缩苯胺．     

Surface rumples and band gap reductions of cubic BaZrO3 （001） surface studied by means of first-principles calculations

Electronic properties of the （001） surface of cubic BaZrO3 with BaO and ZrO2 terminations have been studied using first-principles calculations. Surface structure, partial density of states, band structure and surface energy have been obtained. We find that the largest relaxation appears in the first layer of atoms, and the relaxation of the BaO-terminated surface is larger than that of the ZrO2-terminated surface. The surface rumpling of the BaO-terminated surface is also larger than that of the ZrO2-terminated surface. Results of surface energy calculations reveal that the BaZrO3 surface is likely to be more stable than the PbZrO3 surface.     

Potts-Ising model for simulation of polarization switching in polycrystalline ferroelectrics

This paper proposes a scheme based on the Potts and Ising models for simulating polarization switching of polycrystalline ferroelectrics using the Monte Carlo method. The polycrystalline texture with different average grain size is produced from the Potts model. Then Ising model is implemented in the polycrystalline texture to produce the domain pattern and hysteresis loop. The domain patterns and hysteresis loops have been obtained for polycrystalline texture with different average grain size. From the results of domain pattern evolution process under an applied electric field using this scheme, an extended domain, which covers more than one grain with polarization aligned roughly in the same direction, has been observed during the polarization reversal. This scheme can well reproduce the basic properties of polycrystalline ferroelectrics and is a valuable tool for exploring the physical properties of polycrystalline ferroelectrics.     

Ferroelectric Properties of Polycrystalline Ceramics with Dipolar Defect Simulated from the Potts--Ising Model

Physical properties of polycrystailine ferroelectrics including the contributions of the fixed dipolar defects and the average grain size in the Potts-Ising model are simulated by using the Monte Carlo method. Domain pattern, hysteresis loop and switching current of the polarization reversal process are obtained. Two processes are considered in our simulation. In the first one, the grain texture of ferroelectric ceramics are produced from the Ports model, and then the Ising model is implemented in the obtained polycrystailine texture to produce the domain pattern, hysteresis loop and switching current. It is concluded that the defect has the ability to decrease the remnant polarization P~ as well as the coercive field E~. The back switching is obviously observed after the electric field is off, and it shows some variation after introducing the fixed dipolar defect. Meanwhile, the spike of the switching current is found to lower with the increasing defect concentration and the decreasing average grain size.     

新型压差式吸附式制冷机的设计

设计了一种以太阳能为驱动力,利用渗透压将水分从蒸发器端传输到冷凝器端的压差式吸附制冷机.水分先在蒸发器端被吸附板吸收,再通过渗透压自动运输到最后环节段,并被膨胀物质间歇式地挤压出吸水材料,进入冷凝器,从而保证水分不断从蒸发器抽出,产生制冷效果.通过改变太阳能制冷系统的四通换向阀的开启方向,实现吸附式制冷系统的连续制冷.     

与实践相结合的职中英语教学

由于经济建设发展的需要,国家正在大力发展中等职业技术教育,这是有目共睹的事实。那么,英语学科作为中等职业技术学校学生学习的薄弱环节,该如何在这一发展的大潮中前进呢?     

介孔材料负载杂多酸催化剂催化乙醇脱水制乙烯

采用浸渍法以一种介孔分子筛为载体负载l2磷-钨酸,制得不同负载量的固体酸催化剂.通过X射线衍射、傅里叶红外、N2吸附-脱附、透射电镜等表征手段对载体和催化剂进行表征.此外,采用乙醇脱水制备乙烯的反应评价该系列催化剂的活性,结果表明:在相同的反应温度下,催化剂的反应活性随着负载杂多酸量的增加而增大;对于负载量相同的固体酸催化剂,乙醇的转化率和乙烯的产率随着反应温度的升高而增大.