维拉诺瓦巴奎因城市公园

维拉诺瓦巴奎因城市公园坐落在里斯本市区，倚靠葡萄牙最长的河流——塔古斯河的右岸。在塔古斯河谷的大型综合项目中，包含了对这片10hm^2土地的改造，以重新评估它的城市和景观价值。     

神探出更

记者朱岩报道由爱特信公司与Intel公司共同开发的中文搜索引擎“搜狐”(SoHoo)于2月25日诞生了(www.sohoo.com.cn)!被称为“中文网络神探”的SoHoo不仅是爱特信公司为中文互联网世界带来的导航地图,且已成为169北京信息港“网上搜索”的重要部分。 SoHoo采用人机结合的方式对所有有益互联网发展的网站和网页进行收集,并参照分类学原理对搜集到的信息进行人工分类。它采用层层相     

狐虎四目相对

SOHOO和YAHoo!怎么了?为什么互相盯着对方?对干与外国企业的合资与合作,我们已经司空见惯了然而,因不愿失去自己的品牌而最终放弃合作机会的例子亦比比皆是。乐凯胶卷一直苦苦地与柯达、富士抗争;燕京啤酒始终拒谈合资;     

网络设备赠交大

6月23日,威斯康(WESTCON)亚洲有限公司向西安公路交通大学赠送了高档ATM交换机、10M/100M以太网交换机和网管集线器等全套网络设备,这些设备将用于交通网络培训中心的建设。威斯康是Bay Networks全球总分销商,此次捐赠给交通网络培训中心的设备均是Bay Networks公司的产品,该中心的系统集成工作由北京数波电脑网络公司承担。为适应现代化交通运输的发展和中国交通运输     

Airborne Doppler lidar techniques for observing severe thunderstorms

On 30 June 1981 the wind fields around an Oklahoma severe thunderstorm were observed in detail using an airborne Doppler lidar operated by NASA. Despite uncertainties caused by inertial navigation errors and problems in sampling some of the aircraft attitude and motion parameters, reasonably clear pictures of the distributions of relative reflectivity, horizontal wind velocity, and velocity spectral width near the cloud base have been obtained. Aspects of the design and functioning of the NASA lidar relevant to the collection and analysis of the data are described.     

Biosynthesis and identification of volatiles released by the myxobacterium Stigmatella aurantiaca

The volatiles released by agar plate cultures of two strains of the myxobacterium Stigmatella aurantiaca (strains Sg a15 and DW4/3-1) were collected in a closed-loop stripping apparatus (CLSA) and analyzed by GC-MS. Large numbers of substances from different compound classes (ketones, esters, lactones, terpenes, and sulfur and nitrogen compounds) were identified; several of them are reported from natural sources for the first time. The volatiles 2-methyltridecan-4-one (17), its isomer 3-methyltridecan-4-one (20), and the higher homologue 2-methyltetradecan-4-one (18) were identified in the extracts of both strains and were synthesized. In addition, strain Sg a15 produced 2,12-dimethyltridecan-4-one (19), 2-methyltridec-2-en-4-one (23), and a series of phenyl ketones, among them 1-phenyldecan-1-one (14) and 9-methyl-1-phenyldecan-1-one (16), whereas strain DW4/3-1 emitted traces of 10-methylundecan-2-one (21). The biosynthesis of 14 and 16 was examined in feeding experiments with deuterated precursors carried out on agar plate cultures. The leucine-derived starter unit isovalerate was shown to be incorporated into 16, as was phenylalanine-derived benzoic acid into both 14 and 16. The results point to formation both of the phenyl ketones and of the structurally related aliphatic ketones through an unusual head-to-head coupling between a starter unit such as benzoyl-CoA and a fatty acyl-CoA, followed by decarboxylation.     

用Alltech DS-Plus~(TM)离子色谱抑制器测定有机弱酸

葡萄糖酸、乙酸、甲酸、丙酮酸、山梨酸等有机弱酸在流速为 1 m L/ min,淋洗液的浓度为 1mmol/ L Na HCO3 ,用 Alltech DS- Plus TM抑制器时能很好地检测。弱电离物质检测限分别为 0 .5 0 0μg/ m L、0 .1 45 μg/ m L、0 .0 97μg/ m L、0 .1 95 μg/ m L、1 .0 78μg/ m L(S/ N=3 ) ,具有良好的线性关系和重现性。对饮料样品进行测定 ,结果令人满意。