从板块构造学说的创立看当代地学理论研究发展趋势

板块构造学说是在大陆漂移说等理论基础上，利用现代先进探测技术获得的丰富资料，并吸收相关科研成果，由欧美科学家联合创立的新的全球构造模式。它的诞生标志着地学发展史上一场革命，并对当代地学理论研究发展趋势，产生深远影响：     

On the possibility of using an electromagnetic ionosphere in global MHD simulations

Global magnetohydrodynamic (MHD) simulations of the Earths magnetosphere must be coupled with a dynamical ionospheric module in order to give realistic results. The usual approach is to compute the Reld-aligned current (FAC) from the magnetospheric MHD variables at the ionospheric boundary. The ionospheric potential is solved from an elliptic equation using the FAC as a source term. The plasma velocity at the boundary is the E × B velocity associated with the ionospheric potential. Contemporary global MHD simulations which include a serious ionospheric model use this method, which we call the electrostatic approach in this paper. We study the possibility of reversing the flow of information through the ionosphere: the magnetosphere gives the electric Reld to the ionosphere. The Reld is not necessarily electrostatic, thus we will call this scheme electromagnetic. The electric Reld determines the horizontal ionospheric current. The divergence of the horizontal current gives the FAC, which is used as a boundary condition for MHD equations. We derive the necessary formulas and discuss the validity of the approximations necessarily involved. It is concluded that the electromagnetic ionosphere-magnetosphere coupling scheme is a serious candidate for future global MHD simulators, although a few problem areas still remain. At minimum, it should be investigated further to discover whether there are any differences in the simulation using the electrostatic or the electromagnetic ionospheric coupling.     

Effects of basin edge on the distribution of damage in 1995 Dinar, Turkey earthquake

An earthquake of magnitude M_L=5.9 occurred in Dinar, a town located at the edge of an alluvial basin in Southeast Anatolia, Turkey. Inflicted structural damage throughout the town was highly concentrated in a region located on the alluvium and adjacent to the rock outcrop bounding the eastern side of the town. As an attempt to explain this discrepancy, possible effects of the edge of basin on which the town is located were investigated through 1D and 2D response analyses. Response spectra, computed at distinct locations of the town were contrasted to the building damage statistics of the three zones identified in the town. It is found that the 1D analyses considerably underpredict the spectral response in the heavily damaged area. Differences between the spectral responses obtained from the two approaches diminish with increasing distance from the rock outcrop. These results, which indicate that the 2D amplification was significant over a distance from the edge of the basin, provide a meaningful explanation for the observed distribution of damage throughout the town.     

Closed‐form solution for seismic response of adjacent buildings with linear quadratic Gaussian controllers

Closed‐form solution for seismic response of adjacent buildings connected by hydraulic actuators with linear quadratic Gaussian (LQG) controllers is presented in this paper. The equations of motion of actively controlled adjacent buildings against earthquake are first established. The complex modal superposition method is then used to determine dynamic characteristics, including modal damping ratio, of actively controlled adjacent buildings. The closed‐form solution for seismic response of the system is finally derived in terms of the complex dynamic characteristics, the pseudo‐excitation method and the residue theorem. By using the closed‐form solution, extensive parametric studies can be carried out for the system of many degrees of freedom. The beneficial parameters of LQG controllers for achieving the maximum response reduction of both buildings using reasonable control forces can be identified. The effectiveness of LQG controllers for this particular application is evaluated in this study. The results show that for the adjacent buildings of different dynamic properties, if the parameters of LQG controllers are selected appropriately, the modal damping ratios of the system can be significantly increased and the seismic responses of both buildings can be considerably reduced. Copyright © 2001 John Wiley & Sons, Ltd.     

Kinetics of the reactions of hydroxyl radicals with aliphatic ethers studied under simulated atmospheric conditions

Rate coefficients have been measured for the reactions of hydroxyl radicals with a range of aliphatic ethers by a competitive technique. Mixtures of synthetic air containing a few ppm of nitrous acid, isobutene and an ether were photolyzed in a Teflon-bag smog chamber. From the rates of depletion of the ether and of the isobutene, and based on the value of the rate coefficient k(OH+i-C₄H₈)=5.26×10^-11 cm³ molecule^-1 s^-1, the following rate coefficients were obtained for the hydroxyl radical reactions at 750 Torr and at 294±2K in units of 10^-12 cm³ molecule^-1 s^-1: diethylether = 12.0±1.1, di-n-propylether = 15.3±1.6, di-n-butylether=17.1±0.9, ethyl n-butylether = 13.5±0.4, ethyl t-butyl-ether = 5.6±0.5, and di-isobutylether = 26.1±1.6. The quoted error limits correspond to 2 standard deviations but do not include any contribution from k(OH+i-C₄H₈) for which the error limits are estimated to be about ±10%. The results are discussed in relation to the available literature data and considered in terms of the structure-activity relation for hydroxyl radical reactions with organic molecules.     

Further studies of the temperature dependence of the rate coefficients for the reactions of OH with a series of ethers under simulated atmospheric conditions

The following temperature-dependent rate coefficients (k/cm³ molecule^–1 s^–1) of the reactions of hydroxyl radicals with aliphatic ethers have been determined over the temperature range 247–373 K by a competitive flow technique: diethyl ether,k _OH=5.2×10^–12 exp[(262±150)/T]; methyln-butyl ether,k _OH=5.4×10^–12 exp[(309±150)/T]; ethyln-butyl ether,k _OH=7.3×10^–12 exp[(335±150)/T]; di-n-butyl ether,k _OH=5.5×10^–12 exp[(502±150)/T] and di-n-pentyl ether,k _OH=8.5×10^–12 exp[(417±150)/T]. The data have been measured relative to the rate coefficientk(OH + 2,3-dimethylbutane)=6.2×10^–12 cm³ molecule^–1 s^–1 independent of temperature.Previous discrepancies in the room-temperature rate coefficients for the OH reactions with ethyln-butyl ether and di-n-butyl ether, obtained in the flow and static experiments of Bennett and Kerr (J. Atmos. Chem. 8, 87–94, 1989;10, 29–38, 1990) compared with those of Wallingtonet al. (Int. J. Chem. Kinet. 20, 541–547, 1988;21, 993–1001, 1989) and of Nelsonet al. (Int. J. Chem. Kinet. 22, 1111–1126, 1990) have been resolved. The results are considered in relation to the available literature data and evaluated rate expressions are deduced where possible. The data are also discussed in terms of structure-activity relationships.     

Hydrogeological and geochemical study of the springs in San Severino Lucano territory (Southern Italy)

A hydrogeological and geochemical study is presented for the San Severino Lucano region of southern Italy. In this region, groundwater circulation occurs in rocks lithologically different from one another (metaophiolites, carbonate rocks, etc.). Many springs drain this region. The Frido springs are the most important both for their great volume of flow and for their water quality. A water balance estimated for the recharge area of the Frido springs suggests that during the period 1938–1958 the evapotranspiration represents 54.8 percent, runoff 21.2 percent, and infiltration to groundwater 34 percent of rainfall. The springs studied have a meteoric origin and their waters are mostly acid carbonate-alkaline earth type. The reservoir rocks appear to be the only discriminating factors for the chemical composition of the waters analysed.     

仅依据汇流系统出流资料确定Nash模型参数的研究

从理论上建立缺乏水文资料或水文资料不配套情况下的流域汇流计算方法是水文学家长期追求的目标.在分析半个世纪以来这方面主要研究成就的基础上,认为确定流域汇流模型参数的途径可划分为三类.对其中仅根据汇流系统出流资料确定Nash模型参数的理论公式和实施步骤作了详细探索,取得了初步成果,指出了进一步研究的方向.建议的方法对我国干旱、半干旱内陆边远不易布设足够雨量站点的地区的水文计算和预报工作具有实际意义.     

The geothermal regime of the northern Yukon and Mackenzie delta regions of northwest Canada — studies of two regional profiles

Temperature data from deep petroleum exploration wells and thermal conductivity estimates based on net rock analysis data have been used to make terrestrial heat flow estimates along two profiles across the sedimentary strata of the Mackenzie Delta, northern Yukon, and offshore Beaufort Sea regions.Both profiles exhibit low heat flow values that range from 34 mWm^–2 to 58 mWm^–2, and little change occurs over large distances in the continental part of the area. Low heat flow values (<40 mWm^–2) occur in the Beaufort-Mackenzie Basin and Rapid Depression, both of which are areas of thick successions of Cretacecus and Tertiary clastic sedimentary strata. High heat flow values of almost 80 mWm^–2 occur to the south in the Taiga Nahoni Foldbelt and values as high as 60 mWm^–2 are indicated along the Aklavik Arch Complex, northeast of Aklavik.The regional variations of effective thermal conductivity are insufficient to account for the heat flow variations along the profiles, and so these may indicate deep radiogenic or other heat sources.