Substantiation of Application of Overburden Rehandling in Flat-Dipping Deposits

The layer reexcavation ratio is proposed to use for determination of overburden thickness in the combined conveying and direct-dumping systems of mining by draglines with haulage to goaf. It is established that this method ensures the decrease in costs of mining the horizontal and flat-dipping deposits.     

Investigation into Displacement of Placer Gold Particles

The experimental research in displacement of gold particles in washed-out thickness of sand-gravel layer is conducted. The parameters of ability of gold particles to migrate in pulp flow are determined, and their immersion into loose soil is investigated.     

低渗透储集层中油水层的地球化学综合判识——以济阳坳陷基山砂岩体为例

为了提高低渗透油藏油、水层识别的准确性，以济阳坳陷惠民凹陷基山砂岩体低渗透油藏为研究对象，探索以地球化学方法综合判识储集层流体性质的方法。以试油数据为参考，首先以热解定量方法初步评价，油层与油水同层、油水同层与水层的ST界限分别定为4．00mg／g及2．00mg／g；再以热解色谱定性方法将水层（或干层）与油层及油水同层明确区分；仍不能有效区分的油层及油水同层，则辅以热解参数表征的储集层变异系数进一步评价，变异系数高于0．3的为油水同层，低于0．3的为油层。具单一油源的多口井，可借助菲与二苯并噻吩（P／DBT）将油层及油水同层准确识别，P／DBT值大于12．5则为油层、小于等于12．5则为油水同层。对于相变较快，泥质薄层较多的低渗透油藏，利用热解参数S1／S2可评价储集层的真假隔层及油柱的纵向连通性。图4参17     

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.     

Emission Of Volatile And Semivolatile Organic Compounds From Waterborne Paints – The Effect Of The Film Thickness

A waterborne paint was applied to tin plated steel sheets with three different film thicknesses. The emission of volatile and semivolaile organic compounds ((S) VOCs) from the samples was measured in small climatic chambers under standard conditions over a two-week period. The purpose of the study was to evaluate the effect of the film thickness on the emission rate decay. First order decay models, including sink effects for the high boiling (S) VOCs, were fitted to the concentration versus time data. The results showed that the first order rate constants decrease with increasing film thickness. In uddition, the results indicated that the emissions of the (S)VOCs in the waterborne paint film seemed to be controlled by evaporation. The thicknesses of paint films used in climatic chamber tests to estimate emission rates for product compurison or emission prediction must be known in order to prevent erroneous conclusions     

工程变更及其管理

本文以京秦高速公路 (廊坊段 )为例介绍了在机电工程实施中针对工程变更采用的一套严密科学的工程变更管理程序。履约各方在执行程序过程中 ,职责分明 ,有效地保证了整个项目的顺利实施。     

板料折弯机调节机构的改进

通过调节机构的改进,重复精度达到了要求,减少了废品量,节约了成本,提高了生产效率。     

Use of chemical variation and predation as plant defenses byEncelia farinosa against a specialist herbivore

Larvae of the monophagous herbivore,Trirhabda geminata, selectively eat particular plants and plant parts of its natural host,Encelia farinosa. Measurements of leaf damage and larval positions on branches through time support this observation. Time-lapse movie photography revealed that larvae are sufficiently mobile to search most of a plant in a 48-hr period and that aggregations were the result of larval activity and not directly the result of oviposition. Experiments withT. geminata larvae on artificial diets containing a range of natural concentrations of chemical extracts fromE. farinosa leaves showed that the larvae grew significantly slower and had a lower overall survivorship at the high concentration. Combining the results of all choice tests, larvae appeared unable to distinguish between high- and low-concentration agar diets. Considered individually, larval preferences for natural production concentrations changed as the season progressed. Early-season larvae preferred low-concentration leaves, while late-season larvae preferred high-concentrations. Measurements of chemical and nitrogen content of leaves selected by larvae in the field confirmed this pattern. Percent parasitism in field-collected larvae increased with season as the larval population decreased. This combination of slowed growth and increasing parasitism and predation is a putative defense strategy ofEncelia farinosa to prevent adaptation by a specialist herbivore to the total range of compounds elaborated.     

计算机在热处理工艺编制中的应用

利用计算机强大的数据处理功能 ,对热处理工艺中的各种数据进行记录和处理 ,并制成各种图表 ,掌握其中的各种规律。使热处理工艺的编制不再是一种经验积累式的工作 ,而是依照其规律制定一次合格的规范的热处理工艺卡片 ,并为将来计算机工艺自动生成的工作打下基础