基于嵌入式的GPS模拟信号源的设计与实现

提出了一套基于嵌入式技术的GPS模拟信号源的设计方案;对GPS卫星信号进行了分析,系统实现中采用了嵌入式技术,侧重于对软件设计部分实现的研究;其中具体研究了源代码开放的实时操作系统uC/OSII和嵌入式GUI系统emWin在嵌入式微控制器S3C2410上移植的方法,分析并处理了在操作系统和GUI系统移植过程中的重点和难点问题,解决了应用系统设计中的关键问题,整个系统结构清晰,运行稳定,实时性很好,能够根据指令输出正确的GPS卫星模拟信号;对嵌入式系统的设计与实现具有普遍的指导意义.     

NVCGM高性能灌浆料的研究及应用

从流变性、竖向膨胀、有效承载接触面积、抗压强度等方面,采用对比试验的方法,系统分析了 NVCGM 灌浆料与国外两种灌浆料、国内某灌浆料的优劣性。试验结果以及工程应用表明,NVCGM 灌浆料是一种综合性能优异的高性能灌浆料。     

Managing uncertainty and discontinuous condition numbers in geometric computation

We consider operations on subdivision surfaces under the strict robustness requirement that these floating-point computations return an object with the same topological form as the true solution. The problems involved may however be ill-conditioned, and defined in terms of uncertain data, and even supplementary interval arithmetic may not ensure robustness. Trapping mechanisms are therefore proposed to resolve this difficulty.     

Finite element simulations of static and sliding contact between a human fingertip and textured surfaces

This paper presents a mechanics study of the variations with position and time of stresses within the dermis and epidermis of a human fingertip when it is loaded and slid over textured surfaces. Its purpose is to examine how fingerprints interact with surface texture to cause stress variations in tune with the sensitivities of Meissner and Pacinian corpuscles through which humans in part interpret tactile sensations. A two-dimensional multilayer elastic finite element model of a fingertip has been created for this purpose. Results show that fingertip’s epidermal ridges have little effect on stress distribution within the fingertip in static loading but significantly increase stress oscillations during sliding over a textured surface. Oscillation frequencies from the sliding simulations are in ranges that should stimulate a fingertip’s Meissner and Pacinian corpuscle nerve endings.     

Materials applications of photoelectron emission microscopy

Photoelectron emission microscopy (PEEM) is a versatile technique that can image a variety of materials including metals, semiconductors and even insulators. Under favorable conditions the most advanced aberration corrected instruments have a spatial resolution approaching 2 nm. Although PEEM cannot compete with transmission or scanning electron microscopies for ultimate resolution, the technique is much gentler and has the unique advantage of imaging structure as well as electronic and magnetic states on the nanoscale. Since the image contrast is derived from spatial variations in electron photoemission intensity, PEEM is ideal for interrogating both static and dynamic electronic properties of complex nanostructured materials. Here, we review the key principles and contrast mechanisms of PEEM and briefly summarize materials applications of PEEM.     

基于电化学检测原理的毒性气体探测器设计

一些工业生产过程中产生的有毒气体会对生产安全、环境保护造成威胁。常见毒性气体的检测一般采用电化学传感器。本文针对电化学传感器的使用对硬件电路要求高的问题,设计了一款使用STM32103系列微控制器的高性能毒性气体探测器。     

基于STC12C系列单片机的DS18B20编程

针对新一代高性能单时钟／机器周期的STC12C系列单片机由于执行速度远高于传统的51单片机而不能直接使用原有单片机程序的问题,采用Keil软件的性能分析器来计算Atmel单片机的执行时间;通过手工计算修改程序段的执行时间,使STC12C系列单片机的执行时间满足数字温度传感器DS18B20的时序要求。测试结果表明STC12C2052能正确读取DS18B20的温度转换值,此方法对于具有时序要求的可编程器件的使用具有一定的参考价值。     

黄陵矿区煤矿井下围岩喷涌气体致灾机理及防治措施

鄂尔多斯盆地南缘黄陵矿区黄陵一号等煤矿在采掘过程中出现井下围岩大量气体喷涌现象,导致矿井停采停掘,对煤矿安全生产构成严重威胁。为了揭示喷涌气体的成因及致灾机理,以地面钻孔补充勘探和钻探资料及围岩气体地球化学参数测试数据为基础,采用气样地球化学特征分析、热演化史模拟、烃源岩对比、运移通道识别等多种方法,查明围岩气体的砂岩储集层平面及剖面分布特征,研究区内异常致灾围岩气体的成因类型和来源,分析围岩气体异常喷涌的致灾机理,建立以顶底板砂岩探抽为主的分源综合立体抽采防治模式。研究结果表明:(1)该区煤矿井下围岩气体喷涌具有突发性、隐蔽性、涌出集中和涌出量大等特点,涌出气体主要成分为甲烷,气体主要来源于围岩;(2)顶、底板围岩气体主要为原油伴生热解成因的油型气,生气源岩为上三叠统延长组长7等段腐泥型主力烃源岩,经燕山运动形成的北东向基底断层及其周围大规模垂直裂缝运移而来;(3)油型气主要储集砂岩层呈区带式分布,受构造和岩性双重控制;(4)针对围岩油型气以游离态储集在砂岩中、由采动裂隙导通涌出的特点,采用分源综合立体抽采的防治模式进行围岩气灾害治理,取得了良好的治理效果。     

不同分子量聚乙烯吡咯烷酮对四氢呋喃水合物形成及生长的影响

聚乙烯吡咯烷酮(以下简称PVP)作为一种抑制能力较强、应用较成熟的水合物动力学抑制剂(以下简称KHIs),一直是国内外学者关注和研究的焦点,但对于不同分子量PVP对水合物形成的影响情况还存在着争议。为此,在常压、变温条件下进行了四氢呋喃(以下简称THF)水合物形成模拟实验,研究了相同加量条件下、不同分子量的PVP对THF水合物形成及生长的影响,并从宏观现象、介观结构和微观机制3个层面对影响机理进行了分析和探讨。结果表明:(1)对于THF水合物的形成,PVP的抑制能力随分子量的增大逐渐增强;(2)对于THF水合物的生长,PVP分子量介于8 000~58 000时,抑制效果较接近且相对较弱,但抑制作用稳定,PVP分子量介于270 000~1 500 000时,在THF水合物生长初始阶段PVP的抑制效果较好,但整个实验过程THF水合物形成的平均速率相对较快,且PVP分子量越大这一现象越明显;(3)PVP的存在增强了THF水合物聚集体的聚集强度。结论认为,该研究成果对于KHIs的研发和实际应用均具有较重要的参考价值。