ICP-MS法测定欧盟玩具新指令限制的17种可迁移元素

根据欧盟玩具安全新指令( 2009/48/EC)的要求,应用电感耦合等离子体质谱(ICP-MS)法测定玩具材料中硼、铝、铬、锰、钴、镍、铜、锌、砷、硒、锶、镉、锡、锑、钡、汞、铅17种可迁移元素含量,使用碰撞反应池技术消除某些多原子离子干扰.方法检出限为0.5～75μg/kg,加标回收率在85.4％～109％之间,相对...     

温和条件下混合碱辅助水热合成硅酸镁纳米管

在混和碱的辅助下, 以普通氢氧化镁和二氧化硅粉末为原料在温和条件下高效合成硅酸镁纳米管。采用XRD, TEM, FTIR, 氮气吸附等多种手段对产物进行了表征, 并对其合成过程进行了研究。结果表明氢氧化钠和氢氧化钾的共融液能提高反应物间的溶解性, 促进反应可以在温和条件下加快进行。250℃下合成硅酸镁纳米管, 传统水热法至少需要7 d, 混合辅助水热合成只需36 h。与传统的水热法相比, 混和碱辅助的水热法是一种温和且高效的过程。     

毛细管电泳药物筛选方法与技术

毛细管电泳（CE）在新药研发领域显示着重要的应用前景。CE使用水溶液介质作为实验体系,保证了药物筛选在类似于生命介质的环境中进行,优于其他传统体外仪器筛选方法。除了维持被筛选分子和作用对象的生物活性外,CE筛选过程着重突出配体与受体之间的相互作用。毛细管电泳药物筛选瞄准与药理学理论相关的重要参数,如结合常数K_b 、结合速率常数K_on 和解离速率常数K_off ,有利于模拟并预测机体内靶标与药物之间的相互作用过程。该文回顾了毛细管电泳进行药物筛选的历史,评述了毛细管电泳药物筛选方法所依据的理论和相对成熟的各种常用方法,并抽取了部分典型实例以及相关技术进行说明,对以亲和毛细管电泳、动力学毛细管电泳为手段的药物筛选方法进行了介绍,包括分子和细胞层次的药物筛选,以及针对不同类型的候选药物的研究工作都有提及。毛细管电泳与多种技术的联用,包括与质谱以及化学发光等联用发挥了更大的效能。联用方法还应用于中药有效成分的筛选。毛细管电泳在DNA编码化合物库筛选中将有良好应用前景。馏分收集的发展为筛选药物提供了广阔前景,它配合指数富集配体系统进化技术为毛细管电泳药物筛选提供了更多可能。总之,毛细管电泳多样可选的药物筛选方法和技术将为新概念的药物筛选与药物评价提供有力支撑。     

统筹学在公交线路上的应用一例

<正>统筹学是研究如何在实现整体目标的全过程中施行统筹管理的有关理论、模型、方法和手段.说的通俗一点,就是系统化的用最有效、最简洁、最低成本来实现目标.统筹是人类社会十分宝贵的精神财富,只要是具有鲜明成就感或明确目的的活动想要取得切实合理和有效的好结果,几乎是都离不开统筹的实践.很多人也许对"统筹"这一名词还有些陌生,但对于古代的田忌赛马却耳熟能详,更有出名的电话服务"排队问题"及"开水泡茶问题"等都属于这一领域.     

一道竞赛题的简解

题目（2006年全国初中数学竞赛（浙江赛区）初赛试题第13题）如图,正方形ABCD和正方形CGEF的边长分别是2和3,且点B,C,G在同一直线上,M是线段AE的中点,连结MF,则MF的长为.解析（坐标法）以BG所在直线为x轴,以BA所在直线为y轴,建立直角坐标系.则A（0,2）,F（2,3）,E（5,3）,AE中点M{...     

Surface relief resonant Brewster filters with multiple channels

In this paper, a new type of resonant Brewster filters （RBF） with surface relief structure for the multiple channels is first presented by using the rigorous coupled-wave analysis and the S-matrix method. By tuning the depth of homogeneous layer which is under the surface relief structure, the multiple channels phenomenon is obtained. Long range, extremely low sidebands and multiple channels are found when the RBF with surface relief structure is illuminated with Transverse Magnetic incident polarization light near the Brewster angle calculated with the effective media theory of sub wavelength grating. Moreover, the wavelengths of RBF with surface relief structure can be easily shifted by changing the depth of homogeneous layer while its optical properties such as low sideband reflection and narrow band are not spoiled when the depth is changed. Furthermore, the variation of the grating thickness does not effectively change the resonant wavelength of RBF, but have a remarkable effect on its line width, which is very useful for designing such filters with different line widths at desired wavelength.     

PLANE ELASTIC PROBLEMS OF DIFFERENT MEDIA WITH CRACKS ON THE INTERFACE

The equllibrium problem for the infinite elastic plane consisting of two different media with many cracks on the interface is discussed.It is transferred to a boundary value problem for analytic functions and then further reduced to a singular integral equation,the unique solvability and an effective method of solution for which are eatablished.A practical example in applications is illustrated,the solution of which is obtained in closed form.     

Influence of coating material on laser damage threshold of TiO_2 films

The optical property,structure,surface properties(roughness and defect density)and laser-induced dam- age threshold(LIDT)of TiO_2 films deposited by electronic beam(EB)evaporation of TiO_2(rutile),TiO_2 (anatase)and TiO_2 Ta_2O_5 composite materials are comparatively studied.All films show the polycrys- talline anatase TiO_2 structure.The loose sintering state and phase transformation during evaporating TiO_2 anatase slice lead to the high surface defect density,roughness and extinction coefficient,and low LIDT of films.The TiO_2 Ta_2O_5 composite films have the lowest extinction coefficient and the highest LIDT among all samples investigated.Guidance of selecting materials for high LIDT laser mirrors is given.     

抛体运动的讨论

抛体运动分平抛运动和斜抛运动．1平抛运动抛出的物体的初速度是水平方向的抛体运动叫做平抛运动．平抛运动在忽略空气阻力时,可以把它看作是水平方向的匀速直线运动和竖直方向的自由落体运动的叠加．在竖直平面内取直角坐标系如图1,并把物体被抛出的那一点作为坐标的原点O,设水平初速度为v_0．