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排序方式: 共有2715条查询结果,搜索用时 15 毫秒
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Math1 is essential for genesis of cerebellar granule neurons 总被引:1,自引:0,他引:1
N Ben-Arie HJ Bellen DL Armstrong AE McCall PR Gordadze Q Guo MM Matzuk HY Zoghbi 《Canadian Metallurgical Quarterly》1997,390(6656):169-172
3.
JC Posnick MD Wells JM Drake JR Buncic D Armstrong 《Canadian Metallurgical Quarterly》1993,19(5):260-266
Fibrous dysplasia is an abnormal fibroosseous process of bone of unknown cause. The incidence of skull involvement varies, painless enlargement being the most common presenting symptom. Change in vision is a rare but recognized finding. We report a 3-year-old boy with extreme fibrous dysplasia involving the skull base, who presented with blindness. He underwent exposure osteotomies of the frontal bones and orbits to provide access for skull base tumor removal. The orbital roofs were reconstructed with microplate-fixed cranial grafts. One and one half years after tumor excision followed by immediate reconstruction, the boy retains facial symmetry, and his ocular function has not deteriorated. 相似文献
4.
Jeff H. Rankin & Thomas M. Froese 《Computer-Aided Civil and Infrastructure Engineering》2002,17(4):256-268
This paper discusses the future requirements of integrated construction management systems and the need to support the management of large volumes of information on several levels. The solution proposes a combination of an efficient user interface and methods to partially automate the creation of the required information through access to stored information from past projects. The research follows the path being established for integrated construction management systems that rely on a standard representation of the industry's information requirements. By exploring the comprehensive aspects of construction planning for an integrated construction management system, the research demonstrates the usefulness of applying sound information representation structures. Through the application of case-based reasoning, the research advances the concepts of planning tools as they apply to integrated systems. The resulting prototype construction management system has the primary characteristic of assisting the user in the manipulation of information in order to generate the initial information requirements of an integrated construction management system. 相似文献
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We report impedance measurements on PVC matrix membranes which contain KBPh4 with varying proportions of valinomycin. In agreement with our earlier measurements the value of the bulk membrane resistance (Rb) is much larger in the presence of valinomycin, indicating that the mobility of K+ is greatly reduced by the valinomycin. Rb shows a linear variation with valinomycin/K+ ratio between 0 and 1, but it is invariant at higher valinomycin/K+ ratios. Thus there is no evidence for a special transport mechanism for K+ in these membranes. 相似文献
7.
TonyArmstrong 《世界电子元器件》2004,(4):27-28
如今的汽车电子系统越来越复杂。同时,汽车环境对任何电子产品来说都是很大的挑战,因为汽车电子系统要求运行电压很宽,并且有很大的瞬态电压和温度变化。另外,性能要求也越来越高,需要多个供应电压以满足系统的不同要求。典型的 相似文献
8.
JeffJu PravasPradhan 《世界电子元器件》2004,(10):30-31
消费电子和通信产业正见证着I/O解决方案从并行到高速串行的转变:能够降低成本、简化设计,并具备可延展性,满足全新带宽的要求。这类接口I/O技术的市场潜力巨大,包括移动电话、DVD-RW和高清晰度LCD电视机,而低功耗、低电磁干扰(EMI)和高数据吞吐量在这些应用中极为重要。因此,业界一直致力于设计和开发这些串行I/O,以低功耗提供高速的数据速 相似文献
9.
TonyArmstrong 《世界电子元器件》2004,(7):38-39
许多微处理器和数字信号处理器(DSP)需要一个核心电源和一个在启动期间必须进行排序的输入/输出(I/O)电源。如果未经过适当的电源排序,可能发生闭锁或过流,从而损害微处理器的I/O端口或诸如存储器、逻辑电路、现场可编程门阵列(FPGA)或数据转换器之类支持设备的I/O端口。为了确保在主电源电压未被适当偏置之前I/O负载不被驱动,对核心电源电压和I/O电源电压进行跟踪是必要的。 相似文献
10.
Chadwin D. Young Gennadi Bersuker Yuegang Zhao Jeff J. Peterson Joel Barnett George A. Brown Jang H. Sim Rino Choi Byoung Hun Lee Peter Zeitzoff 《Microelectronics Reliability》2005,45(5-6):806
Effects of constant voltage stress (CVS) on gate stacks consisting of an ALD HfO2 dielectric with various interfacial layers were studied with time dependent sensing measurements: DC I–V, pulse I–V, and charge pumping (CP) at different frequencies. The process of injected electron trapping/de-trapping on pre-existing defects in the bulk of the high-κ film was found to constitute the major contribution to the time dependence of the threshold voltage (Vt) shift during stress. The trap generation observed with the low frequency CP measurements is suggested to occur within the interfacial oxide layer or the interfacial layer/high-κ interface, with only a minor effect on Vt. 相似文献