电感应力灵敏度在实测中的研究

应力场的观测是预报地震较直接的途径之一,本实验利用异孔深井抽水的加(减)载作应力观测的人工力源,在大量实测数据基础上进行力学分析,得出电感应力观测在满足规范要求时能测到地应力场的变化,但室内标定的应力灵敏度不等于实测灵敏度。用室内灵敏度计算应力值必有明显误差。本结果对电惑应力观测科学具有重要的实际意义。     

NUMERICAL SIMULATION OF MESOSCALE STRUCTURES OF TYPHOON AND OROGRAPHIC EFFECTS USING MM5*

The track,landfall,dynamic and thermodynamic and cloud-rain physical mesoscale structures and their evolution of typhoon HERB 1996 in 36 h from 0000 UTC 31 July to 1200 UTC 1 August 1996 were simulated by using the non-hydrostatic mesoscale model MM5.This period covered the process of typhoon HERB landfall at Taiwan and Fujian Provinces.Results show that the model successfully simulated the landfall process of typhoon HERB,revealed the most important characteristics of the mesoscale dynamic and thermodynamic and cloud-rain physical structure during its landfall.The simulated typhoon track was close to the observation.The center of cyclonic circulation simulated at 0000 UTC on 1 August 1996 (24 h integration) was located in shore near Fuqing,Fujian Province at which the typhoon was reported to landfall two hours later.It shows that strong upward motion formed by low level convergence existed in the eye-wall and subsidence at the eye.The wind field shows clear asymmetrical structure near the typhoon center.The cloud and rainband was screw-typed distributed around typhoon center,and consisted of meso-β scale rain cores.During the period of typhoon HERB staying near and passing over Taiwan,the lower cloud was developed in the eye region so that the previous clear typhoon eye on the satellite pictures became fuzzy.Observation shows that the typhoon center was "warm",but the model simulations with higher space resolution show that in the mid-troposphere the region of eye-wall with stronger upward motion and more cloud-and rain-water was warmer than the eye.During the period of typhoon passing over Taiwan and its following landfall at Fujian,the track of model typhoon deviated about 30 km northward (i.e.,rightward) because of the orographic effects of Taiwan Island,but the strength of the typhoon was not affected remarkably.The amount of rainfall on Taiwan in the 36 h simulations was enhanced more than six times by the orographic lifting of Taiwan Mountain.     

Climato-limnological signals during the past 260 000 years in physical properties of bottom sediments from Lake Baikal

The St.16 core obtained from the Academician Ridge of Lake Baikal in eastern Siberia may span about 260 000 years, and some physical properties of the core samples are closely related to aquatic paleoproductivity and climatic change. The median of grain size, grain density, and water content fluctuate synchronously. They also are connected with change in the abundance of biogenic silica (diatoms). The physical parameters indicate that there were high aquatic productivity periods around interglacial periods (MIS 5 and 7; 70 000-125 000 yr B.P. and 180 000-250 000 yr B.P.). Comparatively large clastics were transported from outside of the lake through various routes (ice rafting, etc.) in addition to fluvial routes during the glacials or 'stadials. There are ca. 20 000 yr, 40 000 yr and 100 000 yr periods in the variations of physical properties. These are related to the three Milankovitch parameters of solar insolation.     

Structural physical parameter identification based on evolutionary-simplex algorithm and structural dynamic response

Evolutionary computation based on the idea of biologic evolution is one type of global optimization algorithm that uses self-adaptation, self-organization and random searching to solve optimization problems. The evolutionary-simplex algorithm is introduced in this paper. It contains floating encoding which combines the evolutionary computation and the simplex algorithm to ovcrcomc the problems encountered in the genetic algorithm and evolutionary strategy methods.Numerical cxpcrimcnts arc performed using seven typical functions to verify the algorithm. An inverse analysis method to identify structural physical parameters based on incomplete dynamic responses obtained from the analysis in the time domain is prcscntcd by using the evolutionary-simplex algorithm. The modal evolutionary-simplex algorithm converted from the time domain to the modal domain is proposed to improve the inverse efficiency. Numerical calculations for a 50-DOF system show that whcn compared with other methods, the evolutionary-simplex algorithm offers advantages of high precision,cfficient searching ability, strong ability to resist noise, independence of initial value, and good adaptation to incomplete information conditions.     

整地对栗钙土物理性质和杨树人工林苗木生长的影响

采用定位观测的方法,系统研究了不同整地规格对栗钙土的物理性质和杨树人工林苗木生长的影响.试验结果表明经整地后土壤物理性质总体上得到改善.但不同规格的整地对栗钙土土壤物理性质的改善程度和对杨树人工林苗木生长的促进作用是不同的.在当前的经济发展水平下,综合考虑整地后土壤物理性质的变化和苗木生长的实际效果,在栗钙土上应采用B规格的整地.     

Age model, physical properties and paleoceanographic implications of the middle Pleistocene core sediments in the Choshi area, central Japan

Abstract   A continuous, well-preserved core was obtained from the Choshi area, on the Pacific side of Japan, to investigate paleoceanographic and paleoclimatic changes around the northwestern Pacific region during the middle Pleistocene. Siliciclastic sequences in the core are divided into five formations – the Obama, Yokone, Kurahashi and Toyosato Formations in the Inubo Group and the Katori Formation, in ascending order. Examination of calcareous nannofossils and magnetic polarities detected four datums in the core sediments of the Inubo Group: the top of Reticulofenestra asanoi , the base of Helicosphaera inversa , the top of Pseudoemiliania lacunosa and the Brunhes–Matuyama boundary. Fourteen marine isotope stages (MIS24–MIS11) were identified in the δ¹⁸O and δ¹³C records based on detected datums and the graphic correlation with the standard stack oxygen isotope curve. Magnetic susceptibility and gamma-ray attenuation porosity evaluator density were also measured and low values characterize the glacial intervals. Biogenic sedimentation by primary production may be larger during the glacial periods because of invasions of nutrient-rich northern surface-waters related to the southward shift of the Kuroshio front in the Choshi area.     

中国人工增雨研究进展

随着全球气候变暖的加剧,水资源短缺问题表现得越来越突出,如何有效地开发利用空中水资源已成为人们关注的热点问题之一。本文回顾了人工增雨的发展历史,概述了当今国内外人工增雨的发展状况,归纳了各地区云状、积云特征、液态含水量、冰晶浓度等云物理特征,并在此基础上对我国各地区尤其是西北地区的增雨潜力进行了分析,最后归纳总结了人工增雨的常用手段、经验和检验人工增雨效果的方法。     

Mechanisms of Cenozoic deformation in the Bohai Basin, Northeast China: Physical modelling and discussions

The Bohai Basin is a petroliferous Cenozoic basin in northeast China (Fig. 1(a)) and has apparent geo- metrical and kinematic similarities with the other Meso-Cenozoic extensional basins located along the eastern margin of the Eurasian Plate[1,2]. Its architec- ture and Cenozoic stratigraphy have been well under- stood from several decades of petroleum exploration. Previous studies have suggested that the Bohai Basinis a typical extensional basin and has two tectonic evolution phases, rift…     

工程物探方法在上海城市建设与管理中的应用

工程物探是各学科和地球物理学的交叉学科,是目前应用地球物理领域中的一个重要的分支,它以地球物理学的理论、方法和技术来研究和勘查各种地球物理场的变化,提取人类活动(工程)对地质体原有状态的影响,探测地下目的体,评价工程质量,为工程的选址、建设、施工质量及安全性做出评价。上海城市建设工程物探的应用和相应的方法技术及工作程序,可供非物探专业的工程技术人员参考和借鉴。