Supra-RPC: Subprogram parameters in remote procedure calls

Remote-procedure calls (RPCs) allow distributed, high-level language programs to communicate and synchronize in the usual manner via subprogram calls. One of the great challenges in RPC research is to preserve the traditiional call semantics despite the distribution and heterogeneity of the new environment. The main contribution of SUPRA-RPC is in addressing the passing of subprograms as RPC parameters. In doing so, SUPRA overcomes a number of technical difficulties, stemming from scoping, side-effects and other sources. Since supporting subprogram RPC parameters is harder than supporting non-subprogram RPC parameters, the three (of six) components of the SUPRA architecture extend in novel ways the traditional functionality found in their counterparts in other RPC systems. The SUPRA stub generator extracts information not only from remote entry interfaces, but from any scope potentially referenced by a subprogram passed as an RPC parameter. In addition to the usual call- and accept-stubs and the marshaling and unmarshaling routines, the generator constructs out-of-scope access stubs, callback' and callback-handling-stubs, and modified parameter subprograms and others. The SUPRA run-time support manages a run-time symbol table to keep track of referencing environments and out-of-scope objects. When an out-of-scope object is unavailable for access or execution on the server, the object is reached by a synchronous, ‘under-the-covers’ callback. The SUPRA process management supports servers with independent threads of control, manages (possibly nested) callbacks and pools of callback handler threads, and maintains correct identification of thread-initiated calls or callbacks. A SUPRA prototype has been implemented on Sun Unix workstations. The prototype supports C, C++ and CommonLisp programs. A prototype graphical demonstration has been implemented as well, that represents RPC concepts in terms of common life objects and situations.     

SiO2膜的薄层化对自组织生长Si纳米量子点发光特性的影响

采用低压化学气相沉积方法,依靠纯SiH4气体的热分解反应,在SiO2表面上自组织生长了Si纳米量子点.实验研究了SiO2膜的薄层化对Si纳米量子点光致发光特性的影响.结果表明,当SiO2膜厚度减薄至6nm以下时,Si纳米量子点中的光生载流子会量子隧穿超薄SiO2层,并逃逸到单晶Si衬底中去,从而减少了光生载流子通过SiO2/Si纳米量子点界面区域内发光中心的辐射复合效率,致使光致发光强度明显减弱.测试温度的变化对Si纳米量子点光致发光特性的影响,则源自于光生载流子通过SiO2/Si纳米量子点界面区域附近非发光中心的非辐射复合所产生的贡献.     

聚电解质自组装膜对聚吡咯原位沉积的影响

采用聚电解质自组装膜对其体材料进行表面化学改性，通过原位聚合在基体材料上沉积聚吡咯薄膜。采用UV－Vis和SEM对聚吡咯薄膜的结构进行了表征，结果表明基体材料经聚电解质自组装膜处理后，能改变聚吡咯薄膜的结构与性能。其中聚苯乙烯磺酸钠自组装膜不仅能明显增加聚吡咯薄膜厚度和改善薄膜均匀性及其与基体材料的附着力，而且能明显改变聚吡咯薄膜的微观结构，提高其导电性。     

C语言的语义特点

C语言是目前最流行的计算机语言之一,它兼有传统高级语言和汇编语言的优点,概念简洁,风格灵活,内涵相当丰富。要真正掌握该语言的精髓和理解其语义并非易事。本文对C语言的语义特点作了深入探讨,并给出了一些重要概念,最后,列举了若干在编程中的常见错误。     

基于演化程序的数据通路综合算法研究

提出了一种基于演化程序的数据通路综合算法，该算法是将演化程序与已知的启发式算法相结合来对较大的设计空间进行智能化搜索；并且讨论了应用该方法以减少硬件资源成本和缩短总的执行时间为目标，对典型的微分方程电路实施调度、分配和数据通路综合的整体优化过程，经实验证明，该算法可以十分有效地提高高层次综合设计的质量。     

垂直堆垛InAs量子点材料的分子束外延生长

用MBF设备以Stranski-Krastanov生长方式外延生长了5个周期垂直堆垛的InAs量子点，在生长过程中使用对形状尺寸控制法来提高垂直堆垛InAs量子点质量和均匀性。样品外延的主要结构是500nm的GaAs外延层，15nm的Al0．5Ga0．5As势垒外延层，5个周期堆跺的InAs量子点，50nm的Al0．5Ga0．5Asnm势垒外延层等。在生长过程中用反射式高能电子衍射仪(RHEED)实时监控。生长后用原子力显微镜(AFM)进行表面形貌的表征，再利用光制发光(PL)对InAs量子点进行观测。     

于沸石分子筛ZSM-5中组装Fe3O4的新方法及其磁性

首次以分步水热合成法于孔径为0.56 nm的沸石分子筛ZSM-5的孔道中成功地组装了铁氧体Fe3O4,并测出了它们的磁滞回线及磁学参数:饱和磁化强度σs、剩余磁化强度σr和矫顽力Hc.实验表明,体相Fe3O4的矫顽力为102 Oe,组装后变小为14Oe,即由体相强磁性材料变为纳米非晶软磁材料,这是纳米粒子的小尺寸效应和量子尺寸效应所致,并由XRD,IR,磁滞回线得到了表征.     

Distribution of Ge Self-Assembled Quantum Dots on Six Ge1- x Buffer Layers

The effect of buried misfit dislocation on the distribution of Ge self-assembled quantum dots (SAQDs) grown on a relaxed SiGe buffer layer was investigated. The strain field of arrays of buried dislocations in a relaxed SiGe buffer layer provided preferential nucleation sites for quantum dots. Burgers vector analysis using plan-view transmission electron microscopy (TEM) verified that the preferential nucleation sites of Ge SAQDs depended on the Burgers vector direction of corresponding dislocations. The measurement of the lateral distance between SAQDs and dislocations together with crosssection TEM observation clarified that the location of SAQDs was at the intersection of the dislocation slip plane and the top surface. The misfit strain should be an additional factor governing the uniformity in size, shape and distribution of Ge SAQDs.     

foxBASE＋与BASIC双向通讯的实现

ｆｏｘＢＡＳＥ＋是现今比较流行的数据库软件之一，但它主要用于对数据库的管理，而计算和绘图等功能欠佳。为了充分发挥高级语言在计算和绘图等项功能中的优势，实现它们之间通讯是一个主要环节。本文介绍的是利用文件转换并读写来实现通讯的方法。