秦始皇兵马俑博物馆室内含硫颗粒物的SEM-EDX研究

本文对秦始皇兵马俑博物馆室内采集的长短期降尘、大气悬浮颗粒物和彩绘漆层进行了SEM-EDX研究，在大气悬浮颗粒、短期和长期降尘中，含硫颗粒的粒径分别为0.9～22.8μm、1.0～29.0μm和1.2～37.7μm，多为石膏与粘土或石英以内部混合的状态存在。降尘中的附着型絮状硫酸钙多于大气悬浮颗粒物中，显示降尘和大气中的二氧化硫发生了累进的化学反应。彩绘漆层表面的坑和裂隙附近观察到原位生长的硫酸钙晶体，显示漆层材料或降尘颗粒物与大气二氧化硫之间的酸化学反应，可能是彩绘漆层表面受侵蚀形成微小坑和裂隙的原因之一。     

Mt. Qomolangma: A barometer for global climate change

After 34-year-long studies,scientists have further justified the Mt. Qomolongma (Mt. Everest) region is sensitive to the global climate change.     

China''''s first intense beam proton linac

China's first intense beam proton linear acceleratorhas been built at the CAS Institute of High Energy Physics in Beijing, marking a major progress in research into the accelerator-driven system for developing clean nuclear energy in this country.     

转基因食品很安全——罗伯特.霍尔施博士访谈

过去千百年来,人们是通过自然基因突变来选择具有某种特定基因、特定性状的生物体,而现在的转基因技术则是通过分子生物学手段直接改变基因的结构.转基因技术究竟是农业生产中人类改造自然的伟大创举,还是有可能对生态环境造成难以清除的基因污染的潜在危险?《科学美国人》杂志对分子生物学专家霍尔施博士与梅隆博士的专访,揭示出支持者与反对者对转基因食品截然不同的态度《科学美国人》:请问您为什么对转基因作物感兴趣?霍尔施:我对它的兴趣来自于我对农业学术上的热爱,我有一种本能的想法就是如果将分子生物学技术应用于改良作物,这将非常有助于农业生产.现在我们已经实现了在更少的土地上生产出更多的食品,对水源和生物多样性的危害变得更小.利用生物技术解决农业生产中的问题不但是需要的而且是迫在眉睫的.由于人口的增长和收入的增加,在今后25年的时间里,全球对食品的需求将至少增加50%.《科学美国人》:请问在环境保护方面,转基因技术最重要的好处是什么?     

Recognizing the face of Johnny, Suzy, and me: insensitivity to the spacing among features at 4 years of age

Four-year-olds were tested for their ability to use differences in the spacing among features to recognize familiar faces. They were given a storybook depicting multiple views of 2 children. They returned to the laboratory 2 weeks later and used a "magic wand" to play a computer game that tested their ability to recognize the familiarized faces and their own face based on the spacing of features. Children performed at chance levels. Follow-up studies confirmed that they had attended to internal facial features and validated the stimuli. The results contrast with studies showing some sensitivity to the spacing of features in infants and preschool children; multiple mechanisms of face processing may make use of spatial relations and develop at different rates.     

Fingerspelling and sign language as alternative codes for reading and writing words for Chilean deaf signers

The study examined the role of sign language and fingerspelling in the development of the reading and writing skills of deaf children and youth. Twenty-six deaf participants (13 children, 13 adolescents), whose first language was Chilean Sign Language (CHSL), were examined. Their dactylic abilities were evaluated with tasks involving the reading and writing of dactylic and orthographic codes. The study included three experiments: (a) the identification of Chilean signs and fingerspelled words, (b) the matching of fingerspelled words with commercial logos, and (c) the decoding of fingerspelled words and the mapping of these words onto the writing system. The results provide convergent evidence that the use of fingerspelling and sign language is related to orthographic skills. It is concluded that fingerspelling can facilitate the internal representation of words and serve as a supporting mechanism for reading acquisition.     

Fuel Burning Rate Model for Stratified Charge Engine

A zero-dimensional single-zone double-curve model is presented to predict fuel burning rate in stratified charge engines, and it is integrated with GT-Power to predict the overall performance of the stratified charge engines. The model consists of two exponential functions for calculating the fuel burning rate in different charge zones. The model factors are determined by a non-linear curve fitting technique, based on the experimental data obtained from 30 cases in middle and low loads. The results show good agreement between the measured and calculated cylinder pressures, and the deviation between calculated and measured cylinder pressures is less than 5%. The zero-dimensional single-zone double-curve model is successful in the combustion modeling for stratified charge engines.     

Beam steering in planar photonic crystal based on its anomalous dispersive properties

INTRODUCTION Photonic crystals (PhCs) are increasingly at- tracting attention due to their ability of controlling light propagation on a wavelength scale, by which a fascinating platform for a new generation of inte- grated optical devices and components can be pro- vided. Many studies on PhCs however, focused on new means of tailoring the emission and propagation of light using the photonic band gap (PBG) property whereby the photon density of states is zero. A PhC with a full PBG re…     

Assessment of semi-empirical mass transfer correlations for pervaporation treatment of wastewater contaminated with chlorinated hydrocarbons

INTRODUCTION Chlorinated hydrocarbons, a class of widely used dry-cleaning liquids, industrial organic solvents, and degreasers, increasingly find their way into drinking water sources, thus posing a very serious health and environmental problem (Love and Eliers, 1982). These organic solvents are known for their stability in the environment and cancer-causing po- tency and cannot be effectively and economically eliminated by current conventional treatment tech- nologies. One of the few av…     

超超临界机组机炉协调系统的min-max模糊模型预测跟踪控制

为了提高非线性超超临界火电机组的控制性能,提出了一种改进的min-max模糊模型预测跟踪控制.首先,建立了 T-S模糊模型来近似非线性机炉协调系统的动态特性.然后,基于包含状态变量和输出变量的扩展模糊模型,在保证闭环系统稳定性和输入在给定约束的同时,推导了 min-max模糊模型预测跟踪控制用于输出调节.为了获得更大的...