东南亚印刷包装信息

·据越南信息网报道,目前岘港市对包装业的投资太少,只有一些私人投资纸品包装厂和塑料袋厂,并且产品种类也很有限.     

调剖用聚合物凝胶体系

介绍5种有代表性的聚合物凝胶体系,主要讨论调剖用聚合物凝胶体系的特点和应用范围.指出了聚合物凝胶体系的几个重要性质及两种类型凝胶体系的凝胶机理,举出了聚合物凝胶体系的现场试验及应用情况.     

信息化经济发展的新动力——写在石龙以宽带速度驶向E-TOWN之际

“我们在一个非常合适的时期,　在一个非常合适的地点,　召开了一个非常合适的会议。”在2003年的“中国城市信息技术应用高层论坛”上,中国市长协会副会长兼秘书长陶斯亮曾过这样一句话。这个“合适的地点”,就是石龙。 广东中心城镇——石龙　　　　美丽的东江蜿蜒而下的北干流与南支流交汇一处,形成一河三埠的风水宝地——石龙。石龙北靠广州,南临深圳,毗邻香港,距广州69公里,深圳78公里,历来都是东江水运的重要港口。　　　　石龙,已有800年的悠久历史,自宋代开始有人定居。由于东江穿境而过,航运极为便利,石龙在明末清…     

Analysis of dinosaur samples by nuclear microscopy

Several dinosaur bone and eggshell fossil samples unearthed at different sites in China were analyzed by means of nuclear microscopy. Concentrations and distributions of elements such as Na, Mg, Al, P, S, Ca, Cr, Mn, Fe, Cu, Zn, As, Br, Sr, Y, Ce, Pb and U, etc. were obtained for each sample. The results of quantitative PIXE and RBS analyses show unusually high concentrations of U and Ce in several samples obtained from a period near the K-T boundary (between Cretaceous and Tertiary periods, 65 million years ago), suggesting that some form of environmental pollution could be the cause of dinosaur extinction.     

基于VME总线的高速A／D缓冲系统的研制

本文介绍一种基于ＶＭＥ总线的高速Ａ／Ｄ缓冲系统的原理和结构。着重阐述了高速数据采集技术，高速ＦＩＦＯ缓冲技术，存储器总线切换技术，ＶＭＥ及ＰＣ／ＩＳＡ总线接口技术在本系统中的成功应用。     

Experimental determination of electron and hole mobilities in MOSaccumulation layers

This letter presents for the first time, the experimentally determined majority carrier mobilities in the accumulation layer of a MOSFET for both p-type and n-type channel doping for a wide range of doping concentrations. The measured carrier mobility is observed to follow a universal behavior at high transverse fields, similar to that observed for minority carriers in MOS inversion layers. At the higher doping levels, the effective mobility for majority carriers at low to moderate transverse fields is found to be very close to the bulk mobility. This is believed to be due to carrier screening of the ionized impurity scattering which dominates at the higher doping concentrations     

Immittance function simulator using a single current conveyor

A novel circuit for realising negative immittance using a single plus-type second-generation current conveyor is proposed. The immittance values of the the circuit, which only use four passive elements, can be orthogonally adjusted. The circuit does not require component matching     

条件中位数L_1-模最近邻估计的渐近性质

本文在－混合随机变量的条件下，讨论了基于几个观察值的条件中位数的L1－模最近邻估计的渐近性质，得到了独立同分布时类似的结论．     

透水性沥青面层材料设计新法及应用

本文提出了一种根据主骨料空隙率设计透水性面层沥青混合料级配的新方法，根据这一方法设计的透水性沥青面层具有良好的路面使用功能，应用前景广阔。