Mechanisms of melt droplets and solid-particle ejection from a target surface by pulsed laser action

We suggest an explanation of the effect of melt droplets and solid particle ejection from a target surface under the impact of laser radiation with intensity 10⁸–10¹⁰ W/cm². We consider the capillary wave instabilities on the evaporating surface of melt, which lead to growth of large-scale surface structures and ejection of macroparticles. The instability increments and characteristic droplet sizes are determined. Conditions are found for droplet-free evaporation in terms of the dynamic pressure of evaporated matter.     

甘肃棘豆挥发性成分研究Ⅰ．精油成分分离与鉴定

草原毒草甘肃棘豆（ｏｘｙｔｒｏｐｉｓｋａｎｓｕｅｎｓｉｓｂｕｎｇｅ）全草经水蒸汽蒸馏得一种淡黄色半固体油状物。应用双柱分别进行ＣＧＣ／ＭＳ／ＤＳ分析和标准品对照，鉴定和初步鉴定了７７种组分，占全部峰面积的８１．２％，其中含量高于２％的有顺－法呢醇（ｃｉｓ－ｆａｒｎｅｓｏｌ）、月桂酸（ｌｉｕｒｉｃａｃｉｄ）、肉豆蔻酸（ｍｙｒｉｓｔｉｃａｃｉｄ）、１２－甲基肉豆蔻酸（ｍｙｒｉｓｔｉｃａｃｉｄ，１２－ｍｅｔｈｙｌ）、６，１０，１４－三甲基十五酮－２（２－ｐｅｎｔａｄｅｃａｎｏｎｅ，６，１０，１４－ｔｒｉｍｅｔｈｙｌ）、十九碳双烯醛（ｎｏｎａｄｅｃａｄｉｅｎｏｉｃａｌｄｅｈｙｄｅ），棕榈酸（ｐａｌｍｉｔｉｃａｃｉｄ）含量高达２８．１％。     

An Efficient Method for Determination of the Degree of Substitution of Cellulose Esters of Long Chain Aliphatic Acids

The determination of the degree of substitution (DS) of fatty acid cellulose esters, representing a broad range of substituents (C₆, C₁₂, C₁₈ and C₂₂), was performed by alkaline hydrolysis of the ester groups and the quantification of fatty acids by gas chromatography-mass spectrometry (GC-MS) as their trimethylsilyl derivatives. The method was optimized and compared with established techniques for the DS determination (elemental analysis and alkaline hydrolysis/titrimetry). The results demonstrated that alkaline hydrolysis/GC-MS is a rapid, reliable and powerful method for analysis of fatty acid cellulose esters, particularly when different acyl substituents are present.     

Effects of urea and a nonionic surfactant on the micellization and counterion binding properties of cetyltrimethyl ammonium bromide and sodium dodecyl sulfate

Micellization characteristics and counterion binding properties of cetyltrimethyl ammonium bromide (CTAB) in presence of urea and a nonionic surfactant polyoxyethylene sorbitan monolaurate (PSML), and of sodium dodecyl sulphate (SDS) in presence of urea as well as of several mixtures of CTAB with a bile salt, sodium cholate (NaC), and sodium chloride have been studied. Both urea and PSML have increased the critical micelle concentration (CMC) of the surfactants, the former being more effective than the latter. The analysis of the results supports the pseudophase micellar model to hold over the mass action model. Pure CTAB micelles bind more counterions (96 %) than pure SDS micelles (87 %), and the decreasing effect of urea on the binding is less in case of the former than the latter. A 41 mixture of CTAB and sodium cholate (NaC) can micellize and the micelles bind 87 % bromide ion, whereas 21 and 11 mixtures do not micellize. Micelles of 11 mixture of CTAB and NaCl can bind counter bromide ions to the extent of 92 %. The limiting concentrations of urea required to effect counterion binding by CTAB and SDS micelles are 0.15 mol dm^–3 and 0.25 mol dm^–3, respectively. Such effect is shown by PSML on CTAB at a ratio 0.281. The activation energy of conduction of SDS has increased in the presence of urea up to a concentration of 4 mol dm^–3, at higher concentrations the activation energy has decreased, the effect being more for surfactant concentration above CMC than below.     

带有实时日历钟的温度检测系统

介绍了一种基于AT89S51单片机、温度传感器DS18B20和日历时钟芯片DS1302的温度检测系统的设计方法,实现对温度和年月日和时间的显示.本设计控制简单,携带和使用都非常方便.     

基于虚拟现实技术的电机的虚拟运行

介绍和分析了虚拟现实技术,提出了基于3DS MAX和VRML的产品网上三维虚拟的展示方法.以典型的三相绕线式异步电动机为对象,基于面向对象的方法来描述其基本结构、主要部件的几何特征、运动特性和功能特点,运用3DS MAX对其进行三维建模、建立其虚拟展示的场景模型,并结合VRML的虚拟交互技术和外部编程接口技术EAI对已建立起来的电动机虚拟场景进行交互式虚拟操作.在此基础上,构建了基于VRML的电动机运行状态模拟的网上展示系统,使得用户可基于Web的互动方式远程、透明地访问、浏览、观看和了解该设备不同视觉角度的三维结构、动画演示、主要特征等.     

基于Visual Basic 2008和OpenGL的3ds文件的读取与控制

使用3DS MAX软件进行建模,并将输入文件利用View3ds软件转换成OpenGL格式,数据文件在Visual Basic 2008中进行读取,通过OpenGL对模型进行重构.这种处理方法即能满足快速建模的需要,又能高效的实现友好的交互功能.     

基于PIC18F248的温度监控系统的研究

为了监控大电流磁体电源的温度变化,采用微处理器PIC18F248进行实时监控。首先设计传感器DS18B20的调理电路,通过添加共模抑制线圈提高系统的抗干扰能力,然后利用CAN总线完成多路多点的数据采集,最后采用LabVIEW驱动CAN接口卡并设计系统接收界面。     

3DS软件分析

３ＤＳ是当前国内外十分流行的动画制作工具．特别是其３．０及其以上的版本能在微机的硬件环境下实现工作站一级硬件环境才能产生的动画效果,融计算机辅助设计与多媒体技术于一体,以其强大的功能蜚声中外．本文将介绍３ＤＳ的主要功能,并与ＡｕｔｏＣＡＤ相关内容进行分析比较．     

一种纯电动汽车蓄电池组温度监测系统的设计

采用ATMEL公司的AT89S52微处理器结合DS18b20温度传感器对纯电动汽车蓄电池组工作温度进行检测，利用数据采集卡USB-6009将检测的数据上传至上位机PC，利用上位机的LabVIEW开发的数据采集和分析软件实现对蓄电池组温度监测。