回转冲击式钻眼机可以改善钻进工作

迴转冲击式钻进是综合了两种标准钻进方法的优点,在坚硬岩石中能获得最高的钻进效率。二次大战后,在欧洲许多矿山上加以利用,由于降低成本从而促使这种机械的发展。     

当确定設計流量最大值时利用歷史流量的效用

最近在烏克蘭苏維埃社会主义共和國科学院水文研究所的著作中發表了德湼泊河罗茨曼卡明卡已經系统化的歷史水位资料。这些資料表明,現存于年志档案及文学等史料中的德湼泊河最高水位资料属于自十八世紀起直到現在为止这一时期內的资料。1951～1952年烏克蘭社会主义共和國科学院水文研究所在收集歷史水位资料时,發現了罗茨曼卡明卡1818～1927年间最高水位資料及1828～     

区間徑流对测站H～Q关系影响的商榷

影响水文测站H～Q关系的因素很多,一般学者和書籍僅論及它受涨落率、迴水、冲淤、結冰、水草等因素的影响,很少介紹区間徑流对測站H～Q关系的影响;虽然,区間徑流对测站H～Q关系的影响可以概括在漲落率和迴水影响之內,但作者檢查長江干流一些測站H～Q关系时,觉得尚有独立分析的意义,特选取1954年万縣、漢口、武穴三站H～Q关系受区間徑流影响的部分,加以分析论証。     

Scaling Law for the Heating of Solar Coronal Loops

We report preliminary results from a series of numerical simulations of the reduced magnetohydrodynamic equations used to describe the dynamics of magnetic loops in active regions of the solar corona. A stationary velocity field is applied at the photospheric boundaries to imitate the driving action of granule motions. A turbulent stationary regime is reached, characterized by a broadband power spectrum Ek approximately k-3&solm0;2 and heating rate levels compatible with the energy requirements of active region loops. A dimensional analysis of the equations indicates that their solutions are determined by two dimensionless parameters: the Reynolds number and the ratio between the Alfvén time and the photospheric turnover time. From a series of simulations for different values of this ratio, we determine how the heating rate scales with the physical parameters of the problem, which might be useful for an observational test of this model.     

Interweaving the public and the private: women's responses to population policy shifts in Singapore

This study examined perceptions of the impacts of the antinatalist (OPP) and pronatalist (NPP) policies in Singapore. Data were obtained from a sample of 209 men and 280 women under 45 years old who lived in Ang Mo Kio New Town in the center of the island. Findings indicate that 53.4% of women said that fertility decisions were joint ones. 50% of women and 65% of men said that family size was jointly determined. Over 70% were aware of the OPP "stop at 2" policy. Those who gave accurate, detailed knowledge were mostly over 35 years old. Knowledge of OPP did not vary by education, but did vary by awareness of incentives and disincentives. 45.4% of women believed that OPP was a necessary state policy; 25.4% did not. 36.4% thought that OPP was fair; 28.3% did not. 60.3% of women said that OPP did influence family size in society, but 63.8% said it did not influence their individual family size. Finances, education, and child care were explanatory factors in individual planning. OPP is viewed as a successful policy not because of ideology, but because of the value placed on improved socioeconomic standards. 58.2% of women and 55.5% of men knew the details about the NPP. 51.9% of women said the NPP would encourage larger family size, but 87.8% said it would not affect them personally. Findings suggest that personal freedoms and public ideology are not binary, public-private concepts in fertility decision making.     

Integrating GB and US census microdata for studying the impact of family migration on partnered women's labour market status

This paper investigates the problems in integrating different data sets for social science research. A cross-national analysis of the effects of family migration on labor market participation rates for female partners was used as an example to concretize these problems. The data used in the cross national analysis came from the 1991 British Census Sample of Anonymised Records and the 1990 United States Public Use Microdata Sample. The problems addressed were the following: data collection; manipulation and reliability; question type and definition; and measurement of individual and family variables. As part of the analysis, some empirical findings were also presented. Significant overall differences between the US and Great Britain (GB) samples were observed, particularly concerning graduate qualifications, marital and employment status, and ethnic group. There were higher numbers of married partners and full-time workers in the US sample, while female partners undertaking part-time employment were greater in GB. Furthermore, the US sample had more couples with a female graduate as compared with the GB sample who had a higher proportion of nongraduate couples. Finally, this paper recognized the importance of cross- national research in the evaluation of national ideological and institutional structures.     

PROGRAM FOR PROCESSING OF HISTORICAL LABORATORY DATA BASED ON FUZZY SET THEORY AS A TOOL FOR DECISION SUPPORT

A computer program(FEA)is presented for processing historical laboratory data.It performs on a list ofsample entries stored in a laboratory information management system.Using an algorithm which is basedon fuzzy set theory,FEA classifies the entries into a limited number of clusters called sample types.Theclassification is fully user-defined.The program transforms the historical data into a representation whichis more suitable for studying the performance of the laboratory or which can be used as preparation for asimulation project.     

直接解释地表地质构造的重力异常剖面的近似方法

前言关于求解引起重力异常的地质体形状的问题,在一般情况下还没有直接的解法.对这种问题.为了求得严格的解必须求助于尝试法(迭代法).对于二度地质体,博特(1960)、福尔尼埃和克鲁皮卡(1973)等人曾较详细地讨论过这一问题.对某些理想化的物体,斯基尔斯(1963)还提出了估计最大深度的方法.对于异常地质体的一般形状和密度差作     

Transport of three herbicides in ground water at Twin Lake test site,Chalk River,Ontario, Canada

A field tracer test performed under natural flow conditions at the Twin Lake test site, Chalk River Laboratories of the Atomic Energy of Canada Ltd. in Chalk River, Ontario, Canada, using tritium and three herbicides (Chlortoluron, Terbuthylazine, and Pendimethalin) was interpreted using the dispersion equation with a combined reaction model. The reaction model couples an instantaneous equilibrium reaction governed by a linear adsorption isotherm with a reversible or irreversible kinetic reaction of the first order, and decay. An improved interpretation method consists of a simultaneous fitting of theoretical concentration and mass-recovery curves to the experimental data, which leads to a more reliable determining of reaction models and improves the accuracy of fitting. Tritium served as the reference tracer to determine the flow velocity, dispersivity, and the recovery of the herbicides. Chlortoluron was slightly delayed by equilibrium exchange with strongly reduced concentration due to an irreversible kinetic reaction and/or decay. Terbuthilazine was slightly delayed by equilibrium exchange, with strongly reduced concentration due to a reversible kinetic reaction with some influence of decay. A strong equilibrium reaction and a strong reversible kinetic reaction without degradation governed the transport of Pendimethalin, reducing considerably its concentration. The results obtained show that simulations based only on Kd and decay constant, especially if these parameters are found in the laboratory, may considerably differ from those performed with reaction parameters determined in properly performed field tests. The dominant reaction types, and the values of parameters found in the study, supply useful information on the transport of the investigated herbicides in sandy aquifers under natural flow conditions.     

A critique of the internal tracer method for estimating contaminant degradation rates

The internal tracer method for estimating contaminant degradation rates separates the attenuation effects not associated with degradation by using a codisposed recalcitrant internal tracer to normalize the degrading contaminant concentration. The remaining attenuation between the internal tracer and degrading contaminant is attributed to degradation and the degradation rate half-life is estimated from the first-order decay equation. An analytical solution of the advection- dispersion equation was used to evaluate flow-and-transport conditions that could result in incorrect estimates of contaminant degradation rate constants. Flow-and-transport characteristics that result in overestimating degradation rates were of particular interest because the internal tracer method often used to demonstrate natural attenuation can achieve remedial objectives. The analytical solution was also used to estimate the magnitude of error associated with using the internal tracer method at an example site and to explain different degradation rates estimated using tracers with different decay rate constants.