如何自动记录水准测量外业数据

介绍了以PC—E500计算机为载体的三、四、五等水准记录程序设计所依据的规范和限差,从PC—E500计算机的操作程序详述了该软件在外业测量中观测记录、i角检查等方面的应用。     

中点单觇法三角高程测量及其精度分析

阐述中点单砚法三角高程测量的原理及精度，并在此基础上得出该方法可达到三、四等水准测量的精度要求。     

重力位模型和GPS/水准数据确定区域似大地水准面

为了有效的利用GPS观测的高程信息,实现GPS观测值中的椭球高向正常高转化,采用EGM96和EIGEN-CG01C重力位模型和某区域的GPS/水准观测数据,应用几何方法确定了该区域1.5'×1.5'分辨率的似大地水准面格网数值模型.该似大地水准面模型内插高程异常与实测GPS/水准点的高程异常进行比较,内符合精度和外符合精度均优于0.040米.表明在地形平坦地区,用平均点间距为10KM的GPS/水准点成果,可以确定厘米级的似大地水准面模型,结合GPS观测成果可以取代四等及以下几何水准测量.     

齿轮泵轴向浮动侧板力矩平衡机制改进

针对外啮合齿轮泵浮动侧板在多工况下磨损问题,提出了一种新型的连通式平衡机制。相比将补偿面压力区与摩擦面压力区相隔开的传统分离式平衡机制,连通式平衡机制将浮动侧板补偿面油腔与侧板摩擦面连通,以使补偿面压力梯度与摩擦面压力梯度同步变化。针对浮动侧板的压力区特征,对侧板表面局部压力分布进行线性化假设,建立了基于离散特征点的参数化力矩模型。理论分析与实验测试表明,以浮动侧板所受合力矩为评价标准,多工况条件下,相比分离式平衡机制,连通式平衡机制提高了浮动侧板的自平衡和自适应能力61.09%。     

基于日志的闪存文件系统的设计

日志文件系统的主要设计思想是跟踪文件系统的变化,在日志节点中记录对文件所作的修改信息.FAT、JFFS、YAFFS等文件系统由于擦写频率过高,对闪存储介质的某些块造成较大的负担从而导致存芯片失效.文章设计的基于日志的闪存文件系统对存取采用的是追加模式,能很好地均衡读写频率,将该系统应用于嵌入式GIS系统,取得较好的效果,但在效率上还有待提高.     

Chemically robust carbon nanotube – PTFE superhydrophobic thin films with enhanced ability of wear resistance

A chemically robust superhydrophobic nanocomposite thin film with enhanced wear resistance is prepared from a composite comprising polytetrafluoroethylene(PTFE) and carbon nanotubes.The superhydrophobic thin films with hierarchical structure are fabricated by spraying an environmentally friendly aqueous dispersion containing carbon nanotubes and PTFE resin on silicon wafer.Thin films with a contact angle of 154.1°± 2° and a sliding angle less than 2° remain superhydrophobic after abrading over 500 times under a pressure of 50 g/cm~2.The thin film is also extremely stable even under much stress conditions.To further the understanding of the enhancement of wear resistance,we investigated the formation of microsized structure and their effects.The growth of microbumps is caused by attracting solution droplet to the hydrophilic islands on hydrophobic surface.     

短距离三角高程测量中测站位置的选择

当测点的位置已确定时,短距离三角高程测量的测量精度与测站所选择的位置有关．文章根据测站的位置与精度最优圆的相互关系,研究了当测站选择在不同位置进行观测时高差测量精度的变化规律,指出了测站位置的选择方法．     

Wear properties of NiAl based materials

The NiAl based materials including NiAl-TiC-Al2O3 composite,NiAl-Cr(Mo)-Hf-Ho eutectic alloy and NiAl-Cr(Mo)-CrxSy in situ composite were fabricated and their wear properties were tested at different temperatures.The results revealed that the NiAl-TiC-Al2O3 composite,NiAl-Cr(Mo)-Hf-Ho eutectic alloy and NiAl-Cr(Mo)-CrxSy in situ composite exhibited the excellent wear properties between 700℃ and 900℃.The microstructure observations exhibited that the self-lubricant films formed on the worn surfaces during the dry sliding test at high temperature,which decreased the wear rate and friction coefficient significantly.TEM observation on the self-lubricant film revealed that it was mainly comprised by ceramic amorphous and nanocrystalline.Compared with the NiAl-TiC-Al2O3 composite,the NiAl-Cr(Mo)-CrxSy in situ composite has lower friction coefficient at low temperature.Such phenomena may be ascribed to the addition of sulfide which contributes much to the formation of self-lubricant,and moreover the TiC addition increase the strength of NiAl based material and its wear resistance.     

复杂形状零件的找平装置及其找平方法

在复杂形状零件的找平装置上有两个互相垂直连接的调节轴,分别为第一调节轴和第二调节轴,其中,第一调节轴被夹在方箱的V形槽中,且一端伸出方箱;第二调节轴的一端连接在第一调节轴伸出方箱的端部;复杂形状工件被夹紧在第二调节轴上。采用上述技术方案可实现对复杂外形的零件的平面进行找平的目的。其结构利用通用的测量工作平板和方箱,找平装置的成本低,找平方法简单、易行、快捷、准确和可靠,具有推广应用的价值。     

两种工程中面积和体积的计算方法探讨

介绍两种工程中面积和体积的计算方法,并针对场地平整中的一些问题,从最小施工土坟量和填挖方基本平衡的角度出发,阐述了采用最小二乘原理确定可供工程设计人员参考的合理的平土高程和平土倾斜坡度的算法,实际应用表明,算法易于实行且计算结果准确。