连续铸造时铝合金的结晶方式和显微组织

由于枝晶网尺寸或枝晶间距同局部凝固时间之间有确定的关系,所以则有可能根据铸态显微组织计算凝固热参数。在不同类型的铝锭(各种直径的直接水冷铸锭,普通模和电磁模铸造的铸锭,辊式、带式及板式铸造机铸出的带板以及Properzi法铸造的棒,横断面上测量枝晶间距,以此作为计算的基础。根据测量结果,本文定性地讨论了铝锭凝固过程中的结晶热参数以及铸造条件对结晶热参数的影响。     

手机短信也骗人

某日,我在教室里坐着,我一同学把他手机放到我面前,让我看一个短信,我看了一下内容,大惊,说有个人通过代理商给他充了1000元活费,我当时就无语了,我说“谁充错了吧？”随即看到了他阴险的笑容,有假,于是我问他怎么弄的,他不说,于是在我紧急采购来的零食的诱惑下,他招了,是一个叫短信骗子的软件做的,告诉我用来骗人不错。     

Visual search in complex displays: factors affecting conflict detection by air traffic controllers

Recent free flight proposals to relax airspace constraints and give greater autonomy to aircraft have raised concerns about their impact on controller performance. Relaxing route and altitude restrictions would reduce the regularity of traffic through individual sectors, possibly impairing controller situation awareness. We examined the impact of this reduced regularity in four visual search experiments that tested controllers' detection of traffic conflicts in the four conditions created by factorial manipulation of fixed routes (present vs. absent) and altitude restrictions (present vs. absent). These four conditions were tested under varying levels of traffic load and conflict geometry (conflict time and conflict angle). Traffic load and conflict geometry showed strong and consistent effects in all experiments. Color coding altitude also substantially improved detection times. In contrast, removing altitude restrictions had only a small negative impact, and removing route restrictions had virtually no negative impact. In some cases conflict detection was actually better without fixed routes. The implications and limitations of these results for the feasibility of free flight are discussed. Actual or potential applications include providing guidance in the selection of free flight operational concepts.     

Work routinization and implications for ergonomic exposure assessment

Jobs in many modern settings, including manufacturing, service, agriculture and construction, are variable in their content and timing. This prompts the need for exposure assessment methods that do not assume regular work cycles. A scheme is presented for classifying levels of routinization to inform development of an appropriate exposure assessment strategy for a given occupational setting. Five levels of routinization have been defined based on the tasks of which the job is composed: 1) a single scheduled task with a regular work cycle; 2) multiple cyclical tasks; 3) a mix of cyclical and non-cyclical tasks; 4) one non-cyclical task; 5) multiple non-cyclical tasks. This classification, based primarily on job observation, is illustrated through data from a study of automobile manufacturing workers (n = 1200), from which self-assessed exposures to physical and psychosocial stressors were also obtained. In this cohort, decision latitude was greater with higher routinization level (p < 0.0001), and the least routinized jobs showed the lowest self-reported exposure to physical ergonomic stressors. The job analysis checklist developed for non-routinized jobs is presented, and limitations of the task analysis method utilized in the study are discussed. A work sampling approach to job analysis is recommended as the most efficient way to obtain a comparable unbiased exposure estimate across all routinization levels.     

刻就刻出“特别精彩”—刻录光盘玩花样

想刻录一张能够启动系统、分区、格式化,让重装系统变得简单的自启动光盘吗?想刻录“自动还原系统光盘”,让系统恢复完全自动化、傻瓜化、一条龙吗?想让制作的光盘放入光驱后会自动打开Winamp播放音乐吗?……使用它们,可以给使用电脑带来无穷的便利与乐趣。实话告诉你,不难的！     

A non-lensed fiber-optic resonance-enhanced multiphoton ionization probe

We have developed a miniature fiber-optic probe with no focusing optics for in situ analysis of volatile organic compounds (VOCs). The probe uses an optical fiber to transmit a laser pulse to a vapor sample causing it to ionize adjacent to the fiber tip through a resonance-enhanced multiphoton ionization (REMPI) process. The distal end of the optical fiber is contained co-axially within 2-mm-inner-diameter stainless steel tubing that serves as an electrode. The electrode is biased at a high positive potential to collect electrons. The current generated is shown to be proportional over about two orders of magnitude to the concentration of the species ionized. Visible wavelength REMPI spectroscopy is used to determine probe sensitivities of 20 ppb (benzene) and 43 ppb (toluene). Designing the probe without focusing optics specifies an achromatic ionization region constant in size and position as the laser wavelength is scanned, which simplifies data collection and reduction. Focusing achromatic systems are discussed and the potential signal improvement is estimated.     

从外到里教你快速辨别翻新笔记本电脑

对于国人而言,购买一款自己喜爱的笔记本电脑（注：以下简称本本）不容易．往往需要存上一两个月的工资才能搞定。因此,谁都不希望买到质量差,甚至是别人用过的二手货或者翻新机。别不信,电脑城里的伙计最喜欢把用来给顾客展示的本本样机高价兜售给用户,很多用户就这样糊里糊涂地把二手本本抱回了家。     

Color characteristics of Cu-Zn-Al alloys

ＣＯＬＯＲＣＨＡＲＡＣＴＥＲＩＳＴＩＣＳＯＦＣｕ－Ｚｎ－ＡｌＡＬＬＯＹＳ￣①Ｌｉ，Ｂａｏｍｉａｎ；Ｚｈａｎｇ，Ｘｉｕｈｕａ（ＳｈｅｎｙａｎｇＩｎｓｔｉｔｕｔｅｏｆＧｏｌｄＴｅｃｈｎｏｌｏｇｙ，Ｓｈｅｎｙａｎｇ１１００１５）ＣＯＬＯＲＣＨＡＲＡＣＴＥＲ...     

开放式系统管理

开放式系统除具备已有的优势外,也构成了重大的信息技术挑战。终端用户只能过多地依靠自动化供应商协助他们保持过程控制网络的安全性。事实上,关于Et趋复杂的开放式自动化构架和专业化信息技术支持的工作正在由厂房工程师来担当。