Deposition of Ti-6Al-4V using laser and wire, part I: Microstructural properties of single beads

In this paper, the microstructural characteristics of Ti-6Al-4V single beads and their dependence on process parameters are addressed. Single beads represent the smallest - and therefore fundamental - unit of additive manufactured components. Bead-on-plates and single beads are produced using a 3.5 kW Nd:YAG laser and Ti-6Al-4V wire. Within 71 sets of process parameters laser beam power, welding speed, and wire-feed speed are varied. The microstructures are investigated by light and scanning electron microscopy, and are divided into several zones according to the thermal history underwent. Microstructural differences of the beads are correlated to the process parameters and discussed. The experiments reveal fundamental microstructural and process characteristics which are helpful for the repeatable and predictable manufacturing and understanding of multi-layered components.     

Kfz-Abstellfl?chen; Befreiung; Ausgleichsabgaben

Im Falle der nachtr?glichen Schaffung der Stellpl?tze, von deren Schaffung eine Befreiung erteilt wurde, besteht kein Rechtsanspruch auf "Befreiung von der erteilten Befreiung".     

Standardization of 68Ge/68Ga Using Three Liquid Scintillation Counting Based Methods

A solution containing ⁶⁸Ge in equilibrium with its daughter, ⁶⁸Ga, has been standardized for the first time at the National Institute of Standards and Technology (NIST) using 3 liquid scintillation-based techniques: live-timed 4πβ -γ anticoincidence (LTAC) counting, the Triple-to-Double Coincidence Ratio (TDCR) method, and ³H-standard efficiency tracing with the CIEMAT¹/NIST (CNET) method. The LTAC technique is much less dependent on level scheme data and model-dependent parameters and was thus able to provide a reference activity concentration value for the master solution with a combined standard uncertainty of about 0.3 %. The other two methods gave activity concentration values with respective differences from the reference value of +1.2 % and −1.5 %, which were still within the experimental uncertainties. Measurements made on the NIST “4π”γ secondary standard ionization chamber allowed for the determination of calibration factors for that instrument, allowing future calibrations to be made for ⁶⁸Ge/⁶⁸Ga without the need for a primary measurement. The ability to produce standardized solutions of ⁶⁸Ge presents opportunities for the development of a number of NIST-traceable calibration sources with very low (<1 %) relative standard uncertainties that can be used in diagnostic medical imaging.     

Thermohydrodynamic studies based on different grade oils in offset‐halves journal bearing

This work presents theoretical and experimental investigations on offset‐halves bearing to access the temperature rise at oil–bush interface with three different grade commercial oils namely Mak 2T, Hydrol 68 and Mak Multigrade at different loads. The Reynolds equation was solved simultaneously along with the energy equation and heat conduction equations by the finite difference method to find the pressure and temperature distribution for offset‐halves journal bearing. The energy equation was solved using parabolic temperature profile approximation technique for faster computation. A comparative study for oil temperatures and thermal pressures for three grade oils was carried out vis‐à‐vis the effect of speed and eccentricity ratio. The temperatures in the oil film were observed to be lowest for Mak 2T oil and highest for Mak Multigrade oil. Copyright © 2011 John Wiley & Sons, Ltd.     

TPMS无线数据传输模块间匹配网络及天线的设计

无线数据传输是TPMS系统设计中最关键的部分。本文基于MOTOROLA公司生产的MC68HC908系列芯片,提出了一种环型天线和匹配网络的设计方法,并给出了设计的电路图,最后对系统进行测试。     

A fuzzy soft flood alarm model

A wide range of hydrological analyses for flood, water resources, water quality, ecological studies, etc., require reliable quantification of rainfall inputs. This work illustrates a fuzzy analysis that has the capability to simulate the unknown relations between a set of meteorological and hydrological parameters. A fuzzy approach to flood alarm prediction based on the fuzzy soft set theory is applied to five selected sites of Kerala, India to predict potential flood.     

40臂井径仪测试技术在防砂工艺选择中的应用——以DXX68C29井为例

DXX68C29井是位于辛68块东三段构造高部位的一口关键井,2011年7月27日因出砂严重而停产,影响产能高达15.4m3。针对该井套窜井段长、封窜后套管内通径有所变化、井斜角变化大的矛盾,应用40臂井径仪测试结果对该井套管内通径的变化进行分析后选择合适的防砂工艺防砂后,较好地解决了该井因出砂不能正常生产的矛盾,并见到了明显效果,该井2011年8月4日开井,已连续生产170d,累计增油1 179.9m3。该技术在DXX68C29井的成功实践为解决同类井的防砂提供了一种新的思路。介绍了40臂井径仪结构、测试原理、技术指标,并通过现场实例应用,分析了该仪器现场应用效果,为解决油藏油井防砂提供了一种新的思路和技术支持。     

基于MC68单片机的避障智能车的设计与实现

设计并实现了一种基于MC68HC908QY4单片机的自主避障智能模型车系统。采用Freescale公司的MC68HC908QY4作为核心控制单元,使用红外传感器采集路况信息。通过对检测信息的分析,自动控制转向电机转向,改变行驶路径,绕过障碍物,从而实现智能车稳定避障。     

基干射频识别卡的会议签到系统(RFIDMSS)的设计和实现

提出了一种基于射频识别卡的会议签到系统的设计方案，阐述了系统组成、主要功能、硬件系统结构及软件系统设计，给出了硬件系统MCU部分的编程框架及软件系统PC机部分主要技术要点，并对其中的技术特点和难点进行了分析。     

采用微控制器MC68HC908LB8带PFC的数控可调光电子照明镇流器

介绍了MC68HC908LB8的主要特点和基于MC68HC908LB8带PFC的数控可调光电子照明镇流器电路。