涡轮流量计在蒸汽流量量值传递中的应用

通过对涡轮流量计检定条件及使用条件一致性限定及技术处理,提高了涡轮流量计使用准确度.然后再通过对空气-蒸汽介质替代换算系数的实验研究,确定了空气-蒸汽换算系数.首次用涡轮流量计作为标准用于蒸汽流量量值的传递,研究了LDQ-KJ-100型气体流量装置,并获得了较为满意的结果.     

涡轮流量计在蒸汽流量量值传递中的应用

0　概述随着科学技术的进步和国民经济飞速发展的需要 ,节约能源 ,合理使用能源已成为我国的一项重要国策。蒸汽及其它气体流量的计量 ,属于国家重要的能源计量。蒸汽流量计的检定技术 ,目前在国内仍处于研究阶段 ,国内一些生产厂相继建立了以蒸汽为工作介质的标准装置。但因耗能太多 ,工作条件不好等原因而在努力寻求以空气为工作介质检定的新途径。经调查 ,目前国内已出现的以空气为工作介质的标准装置主要有二种。一是音速喷咀式 ,其装置测量精度虽满足了检定要求 ,但装置造价高昂 ,每台约 1 0 0万元。实践证明 ,其技术是可行的 ,但投资…     

等精度传递理论在气体流量量值传递中的应用

本文介绍了建立在计量学基本原则基础之上的等精度传递理论的意义以及该理论在气体流量标准装置中的实际应用,丰富了气体流量标准装置设计思想,整合优化了气体流量标准装置的传递环节且具有明显的社会效益。     

变温润滑油涡轮流量计修正技术研究

为研究以变温航空润滑油为工作介质的涡轮流量计仪表系数修正方法,利用变温航空润滑油流量标准装置对4支涡轮流量计在多个温度点下进行了校准试验,通过双指数衰减函数对校准结果进行拟合修正。结果表明,各温度点和流量点涡轮流量计仪表系数与校准结果误差小于1%,修正方法具有较好的通用性。     

涡轮流量计对液体流量的计量

本文介绍用较低准确度的涡轮流量计构成的较高准确度的计量系统以及计量系统不确定度的合成方法，列出了确定流量系数的计算公式。     

高精度大流量气体流量标准装置的研制

介绍了由临界流流量计和标准气体涡轮流量计有机组合、优势互补,分别作为传递标准和核查标准组成的气体流量标准装置的构成、工作原理、实现的主要技术指标及采取的主要技术措施。丰富了气体流量标准装置的设计思想,拓展了气体流量量值传递的途径和方法,且具有较好的社会经济效益。     

涡轮流量计对流体流量的计量

本介绍用较准确度的涡轮流量计构成的较高准确的度计量系统以及计量系统不确定度的合成方法，列出了确定了流量系数的计算公式。     

空气和天然气流量标准装置差异性研究

自上个世纪80年代末以来我国相继建立了以空气为介质的气体流量标准装置用于现场流量计的检定、测试工作.然而,这些空气标准装置和天然气标准装置的溯源方式不相同,其量值也存在着差异.开展不同介质的气体流量工作标准装置的差异性研究,对于保证我国贸易计量现场天然气流量量值的准确、可靠是非常必要的,具有重要意义.本文利用1台涡轮流量计和2台罗茨流量计在空气和天然气流量标准装置上进行了测试实验,通过对仪表系数测量结果的比较和分析,力求找出不同装置之间差异存在的原因,以利于进一步的研究.     

提高涡轮流量计使用准确度的方法

通过对涡轮流最计现行检定方法及检定准确度评定方法的分析,结合涡轮流量计的实际使用情况,总结归纳出了在检定准确度的基础上提高其使用准确度的3种基本方法.     

涡轮流量计仪表系数的测量不确定度评定报告

本文根据JJG1037-2008《涡轮流量计检定规程》和JJF1059-1999《测量不确定度评定与表示》的要求,建立了涡轮流量计仪表系数不确定度评定的测量模型,对影响示值的各种不确定度来源进行分析,最后,获得涡轮流量计仪表系数不确定度评定报告。     

标准金属量器的不确定度评定

根据JJG259-1989《标准金属量器》国家检定规程和JJF1059-1999《测量不确定度评定与表示》国家技术规范的要求,通过采用不确定度A类和B类评定方法,具体分析包括被检量器的液位高度差、计量颈容量、计量颈液位高度差、标准金属量器等分量的产生及所引入的不确定度分量,从而获得标准金属量器测量结果的扩展不确定度。     

Investigating the influence of working memory capacity when driving behavior is combined with cognitive load: An LCT study of young novice drivers

Distracted driving has received increasing attention in the literature due to potential adverse safety outcomes. An often posed solution to alleviate distraction while driving is hands-free technology. Interference by distraction can occur however at the sensory input (e.g., visual) level, but also at the cognitive level where hands-free technology induces working memory (WM) load. Active maintenance of goal-directed behavior in the presence of distraction depends on WM capacity (i.e., Lavie's Load theory) which implies that people with higher WM capacity are less susceptible to distractor interference. This study investigated the interaction between verbal WM load and WM capacity on driving performance to determine whether individuals with higher WM capacity were less affected by verbal WM load, leading to a smaller deterioration of driving performance. Driving performance of 46 young novice drivers (17–25 years-old) was measured with the lane change task (LCT). Participants drove without and with verbal WM load of increasing complexity (auditory-verbal response N-back task). Both visuospatial and verbal WM capacity were investigated. Dependent measures were mean deviation in the lane change path (MDEV), lane change initiation (LCI) and percentage of correct lane changes (PCL). Driving experience was included as a covariate. Performance on each dependent measure deteriorated with increasing verbal WM load. Meanwhile, higher WM capacity related to better LCT performance. Finally, for LCI and PCL, participants with higher verbal WM capacity were influenced less by verbal WM load. These findings entail that completely eliminating distraction is necessary to minimize crash risks among young novice drivers.     

The use of an ultrasonic measuring system to construct a working standard of air flow speed

Some features of the use of the ultrasonic method of measurement to construct a working standard of air flow speed are considered. It is shown that alternate probing of the flow in both directions is promising and it is thereby possible to reduce the random errors of measurements of its speed. The results of a measurement of air flow speed, obtained using an ultrasonic measuring system and a laser Doppler anemometer are compared. __________ Translated from Izmeritel’naya Tekhnika, No. 12, pp. 35–38, December, 2007.     

The implication of capacity reservation contracts in assembly system with asymmetric demand information

This paper investigates an assembly system that consists of one assembler and two suppliers who produce complementary components. The assembler possesses some private demand information that is unobservable to the upstream suppliers, and the two suppliers have to choose their capacity reservations ahead of the selling season. To induce credible vertical information sharing, we design three capacity reservation contracts: the price-quantity contract, the price-only contract and the hybrid price-quantity and price-only contract, so as to identify how the firms’ equilibrium reservation strategies and pay-offs react under different contract schemes. The results show that the assembler obtains the highest pay-off under either the price-only contract or the hybrid contract, which is determined by whether the private demand information or the demand fluctuation is sufficiently high. The suppliers’ optimal contract types are further influenced by their decision sequence. In particular, the supplier who makes decision earlier prefers the hybrid contract, while the supplier who makes decision later prefers any of the three contracts. The supply chain generates the highest pay-off from either the price-quantity contract or the hybrid contract.