4—羟基—4′—X—二苯酮的合成

本文研究了4-羟基-4′-x-二苯酮的合成方法,其中x可为H、CH_3、Br、Cl、OH、CH_3O,反应采用三氯化铝催化,由对甲氧基苯甲酰氯与x-取代笨反应,一步得到目标分子。应用本反应时间短、产率都在75％以上。     

锌镀层的晶体取向

以Ｄ－Ⅰ季胺化合物为添加剂的碱性锌酸盐溶液，在多晶铁基体上用恒电位方法电沉积锌，用 Ｘ－射线衍射法研究沉积层锌晶体的取向．测定了过电位和添加剂浓度对晶体取向的影响，获得一 个重要的结果：电沉积层的（１１２０）择优取向随电沉积过电位的降低和添加剂浓度的提高而增强． 并认为是由于添加剂对各晶面的阻化作用不同，导致镀层形成择优取向，满意地解释了有关的实验 结果．     

现代远程教育模式下教学方式的改变

现代远程教育是对传统教育的补充，是未来教育的重要组成部分，随着现代远程教育的普及，教育方式需要做好相应的改变。     

试论绿色营销的根本要求

绿色是一种理念、哲学和文化，它会影响人们的思想观念和生活方式。随着国际经济发展注重环保与可持续发展趋势的增强，绿色营销正逐渐成为企业价值观念，是企业创造财富、获得利益的重要途径。中国加入WTO后，实施绿色营销工程，是国内企业调整经营结构、开发产品、促进和引导消费，提升持续竞争力的必然选择；实施绿色营销工程，其根本要求是产品绿色化，即生产环境绿色化、生产过程绿色化、产品本身绿色化。     

MFV-Class： a multi-faceted visualization tool of object classes

Classes are key software components in an object-oriented software system. In many industrial OO software systems, there are some classes that have complicated structure and relationships. So in the processes of software maintenance, testing, software reengineering, software reuse and software restructure, it is a challenge for software engineers to understand these classes thoroughly. This paper proposes a class comprehension model based on constructivist learning theory, and implements a software visualization tool (MFV-Class) to help in the comprehension of a class. The tool provides multiple views of class to uncover manifold facets of class contents. It enables visualizing three object-oriented metrics of classes to help users focus on the understanding process. A case study was conducted to evaluate our approach and the toolkit.     

Physiological response of Tamarix ramosissima under water stress along the lower reaches of Tarim River

Tarim River within the boundaries of Xinjiang is the longest inland river in China and its overall length is 2300 km (the main stream is 1321 km). Because of the increasing population in the region and large-scale ex- ploitation of water and soil resource…     

Fabrication and photoluminescence of GaN nanowires prepared by ammoniating GaeO3/BN films on Si substrate

GaN nanowires were successfully prepared on Si（111） substrate through ammoniating Ga203/BN films deposited by radio frequency magnetron sputtering system. The synthesized nanowires were confirmed as hexagonal wurtzite GaN by X-ray diffraction, selected-area electron diffraction and Fourier transform infrared spectra. Scanning electron microscopy and transmission electron microscopy revealed that the grown GaN nanowires have a smooth and clean surface with diameters ranging from 40 to 160 nm and lengths typically up to several tens of micrometers. The representative photoluminescence spectrum at room temperature exhibited a strong UV light emission band centered at 363 nm and a relative weak purple light emission peak at 422 nm. The growth mechanism is discussed briefly.     

Imaging mechanical shear waves induced by piezoelectric ceramics in magnetic resonance elastography

MRI is a noninvasive medical imaging modality for stimulating the development of medical diagnosis tech-nology. Scientists and engineers are now trying to extend the use of traditional MRI scanner to a wider field. The magnetic resonance elastography (MRE…