基于灰色-模糊-改进动量BP算法的矿工安全行为评价方法

根据矿工安全行为自身的复杂性,影响因素的多样性,行为过程的非线性、模糊性、随机性、时变性的特点,从安全生理、安全心理、工程心理、安全管理、生活重大事件、不同文化差异6个方面构建了矿工安全行为心理测量的初试量表。通过相关数学工具确定了与矿工安全行为状况紧密相关的63条测量指标作为评价因素集合,建立了基于灰色-模糊-改进动量BP算法的矿工安全行为状况的综合评价模型。通过实践应用表明,该方法能对矿工安全行为状态进行较为准确的评价,能满足生产现场矿工不安全行为预测的要求。     

Influence of HIP pressure on tensile properties of a 14Cr ODS ferritic steel

An oxide dispersion strengthened ferritic steel with a nominal composition of Fe–14Cr–2W–0.3Ti–0.3Y₂O₃ (in wt.%) was consolidated by hot isostatic pressing at 1150 °C under various pressures in the range of 185–300 MPa for 3 h. The microstructure, microhardness and high temperature tensile properties of the steel were investigated. With increasing compaction pressure the density of specimens also increased, however OM and SEM observations revealed residual porosity in all tested specimens and similar ferritic microstructure with bimodal-like grains and numerous of large oxide particles, located at the grain boundaries. Mechanical testing revealed that compaction pressure has negligible influence on the hardness and tensile strength of the ODS steel, however improves the material ductility.     

全自动尿沉渣分析仪的临床应用评价

目的　对一种全自动尿沉渣分析仪的临床应用进行评价，并建立其对尿液有形成分分析的正常参考范围。方法　从仪器精密度、携带污染率、分析测量范围以及与人工镜检的可比性4个方面进行评价，同时建立仪器检测红细胞(red blood cell，RBC)、白细胞(white blood cell，WBC)、鳞状上皮细胞(squamous epithelial cell，EC)及管型的正常参考范围。结果　RBC低值、中值和高值精密度的变异系数分别为129.10%、20.59%和7.80%；WBC低值、中值和高值精密度的变异系数分别为65.73%、14.30%和13.00%；EC中值和高值精密度的变异系数分别为27.01%和21.46%。RBC、WBC和EC的携带污染率均为0；RBC分析测量范围为0⁸3 608个/μl,WBC分析测量范围为083 608个/μl,WBC分析测量范围为0¹5 624个/μl，细菌分析测量范围根据菌种不同而结果有明显差异。仪器与人工镜检相比，RBC、WBC和EC的一致率分别为82.80%、73.82%和57.56%。男性尿液有形成分的参考范围显示，RBC为015 624个/μl，细菌分析测量范围根据菌种不同而结果有明显差异。仪器与人工镜检相比，RBC、WBC和EC的一致率分别为82.80%、73.82%和57.56%。男性尿液有形成分的参考范围显示，RBC为0⁸个/μl，WBC为08个/μl，WBC为0¹2个/μl，EC为012个/μl，EC为0¹3个/μl，管型为013个/μl，管型为0⁴个/μl，结晶为04个/μl，结晶为0³4个/μl；女性尿液有形成分的参考范围显示，RBC为034个/μl；女性尿液有形成分的参考范围显示，RBC为0¹2个/μl，WBC为012个/μl，WBC为0²1个/μl，EC为021个/μl，EC为0⁴2个/μl，管型为042个/μl，管型为0⁴个/μl，结晶为04个/μl，结晶为0²个/μl。 结论　该全自动尿沉渣分析仪对尿中的RBC和WBC有较好的识别性能，对结晶、管型、真菌、异形细胞等难以自动识别的成分，可利用仪器的审核功能进行人工识别，必要时进行人工复检，为临床提供可靠的检验报告。     

Transimpedance amplifier with a compression stage for wide dynamic range optical applications

A high dynamic input transimpedance amplifier was implemented in 130 nm CMOS technology. The proposed TIA is an inverter with a diode connected NMOS and a gate controlled PMOS loads which is cascode connected with the inverter. The square law compression NMOS increases the input photocurrent up to 10 mA. The TIA has an integrated input referred noise current of 135 nA, 227 MHz bandwidth. The TIA shows a transimpedance gain of 59 dBΩ and a 97 dB dynamic range. The TIA consumes 2.3 mA from 1.5 V voltage supply.     

轴承润滑膜厚度超声检测法的可检测范围研究

对于轴承润滑膜厚度的超声检测,分析了影响刚度模型检测法可检测范围与检测准确性的因素,对比了两种不同轴承材料时刚度模型法可检测厚度范围的变化情况,并进行了实验检测与分析。结果表明:检测轴承与轴颈的介质材料对刚度模型法可检测范围影响较大,不同材料时刚度模型法具有不同的可检测厚度范围。以水润滑轴承材料为例,轴承材料为不锈钢时,刚度模型法最大可检测厚度约为10μm,并且亚微米级厚度的检测分辨率高于微米级;当轴承材料为石墨时,刚度模型法更适合于2~50μm范围内润滑膜厚度的检测。     

Directed test suite augmentation: an empirical investigation

Test suite augmentation techniques are used in regression testing to identify code elements in a modified program that are not adequately tested and to generate test cases to cover those elements. A defining feature of test suite augmentation techniques is the potential for reusing existing regression test suites. Our preliminary work suggests that several factors influence the efficiency and effectiveness of augmentation techniques that perform such reuse. These include the order in which target code elements are considered while generating test cases, the manner in which existing regression test cases and newly generated test cases are used, and the algorithm used to generate test cases. In this work, we present the results of two empirical studies examining these factors, considering two test case generation algorithms (concolic and genetic). The results of our studies show that the primary factor affecting augmentation using these approaches is the test case generation algorithm utilized; this affects both cost and effectiveness. The manner in which existing and newly generated test cases are utilized also has a substantial effect on efficiency and in some cases a substantial effect on effectiveness. The order in which target code elements are considered turns out to have relatively few effects when using concolic test case generation but in some cases influences the efficiency of genetic test case generation. The results of our first study, on four relatively small programs using a large number of test suites, are supported by our second study of a much larger program available in multiple versions. Together, the studies reveal a potential opportunity for creating a more cost‐effective hybrid augmentation approach leveraging both concolic and genetic test case generation techniques, while appropriately utilizing our understanding of the factors that affect them. Copyright © 2014 John Wiley & Sons, Ltd.     

VLSIC的可靠性测试探讨

针对超大规模集成电路(VLSIC)的可靠性测试问题进行了理论分析,叙述了VLSIC可靠性测试技术及特点,并对VLSIC可靠性测试的设计方法与改善进行了归纳总结。     

Strategies to raise the off-design efficiency of chiller machines

Most HVAC systems in large buildings are equipped with centrifugal chillers which are typically designed for maximum efficiency at 70% at 80% of their full-load. But, below about 30% full-load, their part-load efficiency starts to deteriorate rapidly (increasing kilowatts per ton). For older centrifugal chillers, this rapid drop may start at even higher part-load, rendering their operation at low part-load undesirable. In many cases chillers are over-sized, forcing operation below 50% of the full-load most of the time. Furthermore, the field performance of most chiller machines is genearlly not documented, and there is no tradition of recording chiller performance history. There is growing incentive-driven interest in chiller monitoring. But, field visits, discussions with HVAC engineers and opinions from manufacturers have proven that virtually no chiller systems are currently monitored for kilowatts per ton. Only recently has field data gathering been initiated, and part-load performance of chillers in the field started drawing serious attention. The problem, however, still remains poorly disclosed to the end-user. As a result, chiller machines actually operate at much lower efficiency than the design values. There are opportunities for profoundly improving their field performance. Part-load operation is particularly poor for sites with single centrifugal chillers. This research is an appraisal of strategies for improving the part-load performance of chiller systems. A review of simulation results and field data indicate that chiller machines operate at higher kilowatts per ton than allowed for by current technology. Energy consumption of various chiller types and configurations for a generic building indicate that there are possibilities for lowering chiller energy consumption, and these opportunities can be harvested with simple measures.     

溅射法制备Al/Pb金属多层膜

通过直流二极溅射法制备了具有不同调制波长和周期的Al／Pb金属多层膜。分别通过扫描电镜、X-射线衍射试验以及能谱对多层膜的表面形貌、断面形貌、结构和组成进行了分析。结果表明,所制备的Al／Pb纳米多层膜既无新相生成也无非晶相产生;在亚微米尺寸范围内,铝和铅的微粒分布均匀;在纳米尺寸范围内,形成了Pb对Al的包覆。     

基于PIC单片机的真空断路器在线检测系统的设计

介绍了真空断路器各种常见故障、在线监测的必要性.为了提高系统的可靠性、兼容性、降低成本和占用体积,采用了PIC系列单片机作为核心的处理系统,充分利用了这种类型的单片机的低功耗、外围接口配置灵活、驱动能力强等特点.