DDR（2＋1）=DDR3？

相对于其他配件而言,内存的发展始终保持着非常平稳的态势,即使是初级电脑用户也知道,内存的升级换代基本上就是简单的加法关系,DDR2内存的下一代继任者就是DDR3,之后则是DDR4……实际上,DDR3并不只是DDR（2＋1）的加法运算,两者在很多地方是有差别的。     

颠覆黑白之旅

阳光七彩，所以美丽；生活百味，所以精彩；然而，原本缤纷的世界为什么不能在商务领域中体现呢?面对单调的黑白输出文档，人们更希望可以踏上——     

迅驰不仅仅是一种诱惑

3月12日,英特尔发布了集成了无线连接功能的新一代笔记本电脑技术——迅驰移动计算技术,引起了业界的强烈反响,一些笔记本电脑厂商也同期发布了基于迅驰技术的笔记本产品。一个多月过去了,声扬上究竟有哪些迅驰笔记本了呢?e刀客将带你去见识见识。     

投影的轻舞飞扬时代

投影机目前已经成为了业务经理们取得商场之战的重要武器之一。并且,随着其技术的不断更新,投影机的重量和体积也在向着轻薄小巧的趋势发展。面对着市场中新生的这些小个子,相比原来的大块头们有着什么样的优势和特色?用户又该如何进行选择呢?     

LED驱动器的特性

因为能提供高效率,耐久性,较长工作寿命,环保和卓越的视觉效果,LED已经越来越多的出现在工业应用,电子标识和信号灯,家庭和移动设备,汽车和消费电子中。因此,这些LED的驱动器设计也受到了     

晚霜冻害葡萄园产量恢复的途径

1988年4月下旬,一股来自北极的冷空气团侵入摩尔达维亚境内,致使盆地土表及与其相连的坡地温度下降到-4…-6℃,葡萄主干叶幕高度上的温度下降到-1.5℃,同时还有雨加雪。此时葡萄已开始发芽。一般情况下,幼叶在-0.2,-0.3℃以下有冻害,而已萌     

Prevalence and diversity of Campylobacter jejuni in pig herds on farms with and without cattle or poultry

The prevalence and diversity of Campylobacter jejuni was investigated in pig herds on farms with and without cattle or poultry production. A bacteriological screening of pig cecal samples from 247 finisher herds was carried out at the slaughter-house. Subsequently, a follow-up study was conducted in 24 herds (either with or without prior C. jejuni isolation from pigs) in which fecal samples were collected from pigs and, if present, cattle and poultry. Samples were analyzed for presence of Campylobacter, and subsequent analysis included species identification, serotyping, and, for selected strains, pulsed-field gel electrophoresis typing. In the slaughterhouse screening, C. jejuni was isolated from pigs in 21 (8.5%) herds, but no significant difference in prevalence was found between herd types (pigs, pigs and cattle, pigs and poultry). At the slaughterhouse, C. jejuni and Campylobacter coli prevalence in pigs was 2.3 and 90.1%, respectively. In the follow-up study, herd prevalence of C. jejuni was 8.3%, whereas C. jejuni and C. coli were isolated from 0.8 and 92.0% of pigs, respectively. In mixed production herds, C. jejuni predominated in cattle (42.7%) and poultry (31.6%), whereas C. jejuni was only isolated from 1.3 to 2.5% of pigs in these herds. There were no significant differences in C. jejuni or C. coli prevalence in pigs, cattle, and poultry between herds with and without prior C. jejuni isolation at the slaughterhouse. Pulsed-field gel electrophoresis typing did not yield evidence of C. jejuni transmission between cattle or poultry and pigs in mixed production herds. In contrast, pulsed-field gel electrophoresis analysis showed indistinguishable serotypes of C. coli in pigs and cattle in two herds. Verification of C. jejuni-positive pig samples showed that individual pigs can excrete high levels of C. jejuni and that mixed infection with C. jejuni and C. coli was common in C. jejuni-positive pigs. The results of our study suggest that transmission of C. jejuni between pigs and cattle or poultry in mixed production herds occurs infrequently. Detection of indistinguishable C. coli isolates in two herds, however, might indicate the existence of low-level transmission between pigs and cattle in herds of mixed production.     

三氯蔗糖在饮料中的应用

三氯蔗糖是一种白色粉末,易溶于水、甲醇和乙醇,并且在水中溶解时不容易产生起泡现象,易于稀释。三氯蔗糖属于非营养型强力甜味剂,其甜度为蔗糖的600倍,且甜味纯正（具有近似于砂糖的醇和口感及浓郁的甜味）,几乎不被人体吸收,不会引起血糖变化,适宜作低热量食品的甜味剂;同时,三氯蔗糖对牙齿无腐蚀性,且具有安全性高、稳定性好（耐酸碱、耐高温、货架期长）等特点。     

Fate and effects of Camembert cheese micro-organisms in the human colonic microbiota of healthy volunteers after regular Camembert consumption

The objective of this study was to determine i) if Camembert cheese micro-organisms could be detected in fecal samples after regular consumption by human subjects and ii) the consequence of this consumption on global metabolic activities of the host colonic microbiota. An open human protocol was designed where 12 healthy volunteers were included: a 2-week period of fermented products exclusion followed by a 4-weeks Camembert ingestion period where 2x40 g/day of Camembert cheese was consumed. Stools were collected from the volunteers before consumption, twice during the ingestion period (2nd and 4th week) and once after a wash out period of 2 weeks. During the consumption of Camembert cheese, high levels of Lactococcus lactis and Leuconostoc mesenteroides were measured in fecal samples using real-time quantitative PCR, reaching median values of 8.2 and 7.5 Log(10) genome equivalents/g of stool. For Ln. mesenteroides, persistence was observed 15 days after the end of Camembert consumption. The survival of Geotrichum candidum was also assessed and the fecal concentration reached a median level of 7.1 Log(10) CFU/g in stools. Except a decreasing trend of the nitrate reductase activity, no significant modification was shown in the metabolic activities during this study.     

激光烧结成形法制造功能金属件

美国圣第亚国家实验室新近开发了一种制造功能金属制件的新技术———ＬＥＮＳ法,该技术是依靠ＣＡＤ(计算机辅助设计)固体模型通过激光束将一定的粉末材料烧结,不用模子或型具即可形成最高密度的制品。使用钕柘榴石激光器将粉末熔融后凝固,如果改变粉末混合物则可制造不同金属、合金和非金属材料的制件。所用的原材料包括不锈钢、高温合金、钛合金以及一些陶瓷材料。ＬＥＮＳ法依靠制件的计算机模型通过激光沉积系统,实现从底层到顶层逐层变换方向(90度角)地积层成形,适用于宇航工业、汽车工业以及医学领域。(国　文译自《ＡｄｖＭａｔｅｒ…