Ordovician-Silurian Boundary Extinction and Its Relationship to Iridium and carbon Isotope Anomalies

The abundance distributions of more than 40 elements in the No. 502 Ordovician-Silurian (O/S) bounda-ry section at Fenxiang, Yichang have been studied by RNAA and INAA. The results show that in the bounda-ry bed, there is a distinctive Ir anomaly because the Ir concentration abruptly increases to 0.64 ppb.Furthermore, the Ir is positively correlated in abundance variation with some siderophile and sulphophile ele-ments. In the same bed of the O/S boundary section at Huanghuachang, Yichang, there is also a δ~(13)C excur-sion. These geochemical signs support the hypothesis that the terminal Ordovician mass extinction was proba-bly related to extraterrestrial event, and provide new evidence for defining the O/S boundary between theHirnantia-Kinnella and G. persculptus Zones.     

含油砂岩温升过程的声学特性

一、概述目前,在石油开采中,对于粘稠度较高的储油层,用常规的方法难以开采,一般采用注热法(向油层注入高压蒸汽或热水)驱油进行开采。但为了减少不必要的能源消耗,用注热法开采时,必须掌握注热后热液在地层深部的渗流情况,以便了解“热区”的时空变化规律,实现对稠油层开采的控制。根据国外有关资料介绍,含油砂岩的声波速度随温度的升高而降     

生活时间调查研究回顾与展望

随着人们对时间认识的不断深入,生活时间成为生活质量的主要测定指标之一。本文在回顾生活时间调查研究发展过程的基础上,重点介绍了日本和中国生活时间调查及研究的现状特征,并对时空间研究进行了展望。     

Geochemical Anomaly at the Devonian / Carboniferous Boundary,Huangmao, Guangxi,China

Abstract The abundances of nearly 40 elements, Ir included, have been measured using radio-chemical and instrumental neutron activation analysis (RNAA and INAA) across a Devonian / Carboniferous (D / C) boundary section at Huangmao, Guangxi, China. The Ir anomaly has been found in the D / C boundary bed. Its peak value is 156 ppt, richer by a factor of 12 than that in the underlying strata. Besides, as with Ir, other siderophile and chalcophile elements such as Au, Ni, Co, As and Sb are also enriched. The cause for the abundance anomalies of Ir and other elemets is discussed. Neither volcanic eruption nor extraterrestrial impact can explain it satisfactorily. The real mechanism for the anomalies awaits further study.     

Convection model for stratus cloud over a warm water surface

A numerical model is developed to simulate convective stratus cloud formation over the sea. The model is based on quasi-steady state moist plumes advecting over an area of increasing sea-surface temperature with the sea warmer than the air, but it is also a good approximation for non-steady states whenever the model is matched to air-sea temperature differences. Combining the effects of upward transfer of heat and moisture fluxes as well as adiabatic cooling, stratus cloud forms and spreads downward in this field. The depth of the convective field, the sea surface temperature gradient, the liquid water content at cloud top, and the horizontal pressure gradient are the four controlling parameters for the convective field. Alternatively, the wind speed, air-sea temperature difference, and the mixing ratio of the air, derived variables in this treatment, can be taken, with the depth, as the basic parameters.The entity type of convective model used here has the advantage that it models the transport and modification of air parcels and hence provides a method for studying drop size development in stratus clouds. It also uses relationships derived from water tank experiments with plumes and tested in dry convection and so needs no parameters specific to each situation. Its most important feature, however, is that the mean motion of plumes, rather than turbulent diffusion, transports the moisture.The upward growth and erosion of a temperature step increase to produce an inversion can be attributed to liquid water present in haze drops or cloud drops, rather than to turbulent diffusion. Radiative transfer is not a necessary requirement, but may either enhance or slow down the process.     

粗差拟准检定的实施方案设计

拟准检定法是根据真误差与观测值有确定的关系式RΔ=-RL,通过直接解算真误差估值Δ来检测粗差。由于真误差能直接反映粗差的大小，所以这种方法可靠性强。本文主要阐述该方法的实施方案设计思想及其步骤和选择“拟准观测”的一些技巧。     

苏北—鲁东南高压,超高压变质带剥露过程中伸展构造作用

尽管许多地质学家提出了不同的超高压变质岩石形成与折返模式,但高压、超高压变质岩折返与剥露机制仍是大陆造山带动力学研究中的热点和焦点问题。本文明确提出并研究了分布于苏北－胶南变质岩区西北和北部边缘的地壳规模的拆离伸展型韧性剪切带。通过韧性剪切带几何学、运动学、变形环境分析和形成时代的讨论,认为与高压、超高压变质带展布方向斜交的斜向伸展构造作用,是苏北－鲁东南高压、超高压变质带从中地壳抬升至地表的主导     

中等传输距离下的无线功率传输链路第2部分:选择性工作方式

对谐振感应式无线功率传输链路的3种不同的工作方式进行了讨论.第1种工作方式是输出恒定的电压或电流;第2种工作方式采用频率捷变操作,非常适合于不随耦合系数变化的应用场合;第3种工作方式实现负载独立工作并输出恒定的电压或电流.本文讨论并提出了不同情况下的解决方案和相关公式.最后通过实验对提出的理论进行了验证.