Quantum phase transitions in 2D antiferromagnets

Quantum Monte Carlo results for the T = 0 order-disorder transition of two-dimensional dimerized quantum Heisenberg antiferromagnets are presented. For a two-layer model, with the dimers having one member on each plane, the finite-size scaling of the staggered structure factor and the staggered susceptibility is consistent with the 3D classical Heisenberg universality class, as required if the transition is described by the 2+1-dimensional non-linear sigma-model. However, for models with the dimers in a single plane, the behavior does not appear to be consistent with this universality class.     

The influence of preparation conditions on the electrochemical behaviour of CuO in a Li/CuO cell

A dozen CuO samples prepared under various conditions and from different starting materials were evaluated as cathode materials for a primary Li/CuO cell. The “thin electrode” method was used for rapid evaluation of the samples. Both coulombic efficiency and discharge voltage depend considerably on the method of synthesis. No correlation was found between the specific surface area and the resistivity of the samples on the one hand and the cathode performance on the other. Best results were obtained from CuO prepared by the oxidation of Cu₂O under controlled temperature and time of oxidation.     

Process integration in CASE environments

Research in CASE environments has focused on two kinds of integration: tool and object. A higher level of integration, process integration, which represents development activities explicitly in a software process model to guide and coordinate development and to integrate tools and objects, is proposed. Process integration uses software process models (SPMs) a process driver, a tool set, and interfaces for both developers and managers to form the backbone of a process-driven CASE environment. The developer's interface, a working environment that lets developers enact an SPM, and the manager's interface which gives managers and analysts the tools to define, monitor, and control the SPMs that developers are working on concurrently are discussed. The Softman environment experiment, an implementation of process-driven CASE environments with existing CASE environments, is reviewed     

草酸二异辛酯的合成

以酸化膨润土(SO42-/Bentonite)固体酸为催化剂、草酸和异辛醇为原料合成草酸二异辛酯。考察了焙烧温度对催化剂活性的影响。结果表明,焙烧温度为500℃时催化剂活性最好。考察了反应温度、原料配比、催化剂用量和反应时间等因素对酯化反应的影响,确定了最佳酯化反应工艺条件,即n(异辛醇)∶n(草酸)为3.5∶1、w(SO42-/Bentonite)为2.0%、反应温度140℃、反应时间3 h;在该条件下草酸的转化率达到96.4%。催化剂重复使用6次后,草酸的转化率仍可达到94.4%。     

混合结构楼房爆破拆除倒塌范围的确定

通过对混合结构楼房爆破倾倒过程特点的分析,提出了楼房在倾倒过程中的运动计算模型,并应用体积平衡原理,得到这类楼房爆破爆堆参数计算公式,用该公式计算的结果与实例中爆堆实测数据相比较,相对误差不超过11%.     

Acceptability of genetically modified cheese presented as real product alternative

European consumers, in general, have negative attitudes towards the use of gene technology in food production. The objective of this study was to examine whether taste and health benefits influence the acceptability of genetically modified (gm) products when they are presented as real product alternatives. Consumers in Denmark, Finland, Norway and Sweden (n=738) assessed two cheeses: one was labelled as genetically modified (preferred in an earlier product test) and the other as conventional (neutral in an earlier product test). A smaller control group received two cheeses with blind codes. Labelling decreased consumers' intentions to buy the originally preferred gm-labelled cheese, but still the intentions were at the same level with the conventionally labelled option. Participants chose two gm cheeses out of five possible when given the option to take cheese home after tasting. Intentions to buy gm cheese could best be explained by respondents' attitudes towards gene technology and perceived taste benefits. General health interest was also a reinforcer of intentions for gm cheese with reduced fat content.     

基于MOBILE的JK触发器设计

介绍了一种新型量子逻辑单元电路——单稳双稳转换逻辑单元及其工作原理,在此基础上探讨并设计了以MOBILE为基本单元电路的具有同步置位复位功能的边沿型JK触发器电路,从而丰富了量子电路中触发器的类型     

Kinetic Monte-Carlo simulation of network formation

Summary the simulation described in Part I was applied to random step polyaddition of a trifunctional monomer and the results were compared with exact solution for an infinite system. The gel point conversions, the weight-average degree of polymerization before (P _w) and beyond (P _w,sol) the gel point, the sol fraction and the cycle rank were used for comparison. The best way for detection of the gel point conversion is the extrapolation of the gel fraction, w _g, to w _g=0. The largest fluctuations are exhibited by P _w and P _w,sol. To get results closer to the exact ones, one can repeat several experiments with smaller number of units or increase the number of units, the former way being somewhat more economical. Typical orders of magnitude used were 10⁷ monomeric units.