Estimation of errors of hydrogen standard time scale preservation taking account of systematic frequency changes

Metrological characteristics of active hydrogen frequency standards are investigated on the basis of internal and external comparisons. The stability of random changes and drift of hydrogen frequency standards and also the potential capabilities of time scale preservation with effective consideration of systematic changes in their frequency are demonstrated. __________ Translated from Izmeritel’naya Tekhnika, No. 3. pp. 42–45, March, 2007.     

Numerical Study of Scale Effects of Ultra-Thin Nickel Beams

Recent experiments have shown that metallic materials display significant size effects when the characteristic length scale of non-uniform plastic deformation is close to a micron. Couple stress plasticity has been developed to explain such phenomena by Fleck and Hutchinson. The mechanical behaviors of ultra-thin nickel beams in different boundary conditions were studied with the hybrid element developed for couple stress plasticity before. Strong scale effects are found when the beam's thickness is close to the material characteristic length scale. Such phenomena will disappear if the beam' s thickness is greatly larger than the material characteristic length scale. The scale effect is the beams inherent property and it does not change with the change of support conditions.     

油气吸收回收系统的研究及工业应用——(Ⅱ)工业试验及效果分析

在油气吸收回收系统中型试验的基础上，开发了常温常压吸收法工业化油气回收系统，并进行了工业应用。结果表明，该油气回收系统平均回收率可达95．13％，每年可回收汽油529t；装车期间装车口周围环境大气中总烃浓度平均降低98．06％。企业通过实施油气回收系统，节能及经济效益明显，且很好地改善了装车场所的作业环境，克服了油气排放带来的安全隐患。     

Cu-Cr合金高温氧化行为分析

该文用热分析天平，结合金相、X射线衍射(XRD)、扫描电镜(SEM)和能谱(EXD)研究了Cu—Cr合金在不同温度下的氧化行为。结果表明，Cu—Cr合金在700℃-900℃氧化符合抛物线规律，其最外层氧化膜为CuO，内层为Cu2O和Cr2O3，铬有助于提高合金的抗氧化能力。     

催化裂化大油气管线阻焦剂的研究与开发

介绍了阻焦剂的阻聚分散机理，测定了不同组分的阻焦剂对不同性质原料的阻焦效果，并考察了不同加入浓度对阻焦率以及催化裂化产品分布的影响。试验结果表明：加入50—100μg/g的阻焦剂，可使催化裂化大油气管线阻焦率达到53．7％—63．8％，同时对产品分布及产品性质无不良影响，具有技术经济可行性。     

郑411块超稠油试油试采工艺技术应用

郑411块沙三段地层疏松出砂、原油粘度高，属中深层超稠油，常规试油试采方法难以突破出油关，采用APR全通径氮气垫测试、地层与井筒复合防砂、水平井配合直井蒸汽吞吐、氮气泡沫封堵调剖和井筒加热举升稠油等配套工艺技术，取得了较好的效果，为中深层超稠油油藏的开发提供了技术思路。     

Composite scale modeling in the presence of censored data

A composite scale modeling approach can be used to combine several scales or variables into a single scale or variable. A typical application is to combine age and usage together to form a composite timescale model. The combined scale is expected to have better failure prediction capability than individual scales. Two typical models are the linear and multiplicative models. Their parameters are determined by minimizing the sample coefficient of variation of the composite scale. The minimum coefficient of variation is hard to apply in the presence of censored data. Another open issue is how to identify key variables when a number of variables are combined. This paper develops methods to handle these two issues. A numerical example is also included to illustrate the proposed methods.     

Dynamic elastic-plastic behaviour of whipping pipes: experiments and theoretical model

This paper is concerned with the problem of pipe whip, the dynamic response of a high pressure piping system subjected to an end force as the result of a pipe break which releases a jet of fluid from the broken section. Both experimental and theoretical results are presented concerning the dynamic elastic-plastic behaviour of cantilever pipes subjected to a transverse force pulse at the free end. Comparisons between experimental data and theoretical predictions are made for mild-steel pipes with outer diameter-to-thickness ratios of 19.5, 28 and 32. It is demonstrated that, for these geometries, the whipping pipes display three characteristically different responses, viz. elastic, plastic hardening behaviour for thick pipes, elastic, plastic hardening-softening behaviour for moderately thick pipes and elastic, plastic hardening-softening-collapse behaviour for thinner pipes. The experimental data taken from a series of high-speed films are compared with the predictions of the instantaneous shapes of the whipping pipes derived from both a rigid, perfectly-plastic, large deflection, dynamic beam model and a more comprehensive model which incorporates the effects of elasticity and plastic hardening and softening, the details of which are presented in the paper.     

提高润滑油基础油氧化安定性的组合工艺

以生产润滑油基础油的老三套工艺为基础，开发了改善油品氧化安定性的组合工艺。该工艺的主要特点是包括一步络合脱氮过程。实验证明，该组合工艺既可以有效地提高基础油的氧化安定性，又能降低溶剂精制深度，提高基础油收率。