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191.
The study presents a review of modifications to the design of true triaxial test apparatuses and described a new mixed boundary apparatus to study the stress-strain behavior of coarse-grained soil under true triaxial compression conditions. It was shown that the deviatoric component plays an important role in affecting the volumetric compression of coarse-grained soil. The study analyzed the influence of different stress-strain characteristics on the development of lateral earth pressure.  相似文献   
192.
A steady-state, two-dimensional numerical model is used to simulate air temperatures and humidity downwind of a lake at night. Thermal effects of the lake were modelled for the case of moderate and low surface winds under the cold-air advective conditions that occur following the passage of a cold front. Surface temperatures were found to be in good agreement with observations. A comparison of model results with thermal imagery indicated the model successfully predicts the downwind distance for which thermal effects due to the lake are significant.  相似文献   
193.
Ground-based thermal emission measurements of the zenith sky have been made at Peterborough, Ontario since January 1993. In this paper, the measurement of the 6 band of atmospheric CFC-12, an important greenhouse gas, is presented for a cold, clear day in January 1994. A spectrum of the non-CFC-12 emission features has been simulated using the FASCD3P radiation code and measured radiosonde profiles of temperature, pressure and humidity. This has enabled a satisfactory subtraction of the interfering emission features from the CFC-12 emission spectrum. A comparison of the observed and simulated 6-bands of CFC-12 shows good agreement at all frequencies of emission. From these spectra the total downward greenhouse radiative flux from the CFC-12 6 emission based for a very cold day has been estimated to be 0.27 W m−2±10%.  相似文献   
194.
Struck E 《Erdkunde》1985,39(1):50-55
An analysis of changes in migration patterns since World War II between inner Anatolia and eastern Anatolia in Turkey is presented. Four periods are distinguished, the exploratory period until 1950, seasonal migration until 1960, mass migration up to the present, and marriage migration from 1975 to the present. The linkages between previous and potential migrants are noted. (SUMMARY IN ENG)  相似文献   
195.
The earthquake of 6 October 1987 (M = 6.6), which occurred near the Shipunsky Cape, Kamchatka, was the largest crustal event in the vicinity of the main city of Kamchatka — Petropavlovsk-Kamchatsky — during the last three decades. It was followed by numerous aftershocks. This earthquake allowed us to test the effectiveness of the seismic hazard monitoring in Kamchatka, including the seismological, geodetic and hydrogeochemical surveys. The seismic survey provided the location and source nature of the main shock and aftershocks and the seismic environment of the main shock. The geodetic and hydrogeochemical surveys have yielded data on the response to earthquakes of the Earth's surface deformations, water level, and chemical elements concentration in the underground water. As a result, the following data were obtained:

u

  • The earthquake of 6 October had a seismic moment 4–10 E18 Nm, thrust type of faulting and the source volume of 20 × 20 × 10 km3. The maximum intensity was VI–VII (MSK-64 scale) and maximum acceleration 88 cm/s2.
  • Before this event, a relative increase in the number of the upper mantle (depth more than 100 km) moderate magnitude earthquakes during 5 years and a one-year period of seismic quiescence for small shallow earthquakes, were recognized. Significant anomalies in HCO3 and H3BO3 concentrations in the underground waters were observed in the wells a week before the main shock.
  •   相似文献   
    196.
    We examine the various types of mineral waters occurring on the projected specially protected transboundary natural territory “Istoki Amura”, on the Hentei-Dauria neotectonic high. We suggest the pattern of rational utilization of the mineral springs according to the nature conservation status of the terrain (nature reserves, national parks, and public access areas).  相似文献   
    197.
    Doklady Earth Sciences - Analysis of observations of the Earth’s rotational velocity and volcanic activity of the planet from 1720 until 2015 suggests that higher volcanic activity temporally...  相似文献   
    198.
    青藏高原东北缘是柴达木沙尘暴东移的必经之道和沉降区,对青藏高原东北部降尘时空分异特征进行分析,有助于认识青藏高原区域粉尘输送的现代过程和机制。2013年12月至2015年5月分别在青海湖小泊湖(XBH)、西宁多巴(DB)、西宁青海师大科技楼顶(KJLD)设置降尘缸,进行湿法收集。对其降尘通量和粒度特征进行了时空分异特征分析,结果显示,1)西宁地区2014年降尘通量为442~542 g/m~2·a,青海湖XBH采集点指示的2014年降尘通量为415 g/m~2·a,降尘通量年际变化较大,各站点降尘通量季节变化趋势一致,降尘主要集中在冬春季,夏季降尘通量最低;2)各站点降尘粒度组成特征非常相似,以粉砂为主(4~63μm),西宁地区尘暴与非尘暴降尘粒度频率曲线呈近似正态分布,尘暴期间降尘粒径较非尘暴时段大;3)XBH、DB和KJLD 3点所有样品平均粒径分别为37μm、34μm和31μm,中值粒径分别为31μm、27μm和26μm;对比低海拔兰州尘暴粒径特征,发现降尘粒径存在一定的海拔依赖性,即粒度随海拔增高逐渐变粗。  相似文献   
    199.
    Based on GIS and statistical methods, with the help of searching historical literatures and calculating the landscape indices, the land use changes of Qian'an County in both spatial and temporal aspects from 1945 to 1996 has been analyzed in this paper. And the driving forces of land use changes and their ecological effects are discussed too. The main findings of this study are as follows: (1) Land use changed greatly in Qian'an during 1945-1996, characterized by a decrease in grassland, wetland and water bodies, and an increase in cultivated land, saline-alkali land, and the land for housing and other construction purposes. Grassland decreased by 175,828.66 ha, and cultivated land increased by 102,137.23 ha over the half century. Accordingly, the main landscape type changed from a steppe landscape to a managed agricultural ecosystem. (2) Results of correlation analysis show that the land use change in the study area was mainly driven by the socioeconomic factors. (3) The ecological effects of land use change in the area are characterized by serious salinization, degression of soil fertility and the weakening of landscape suitability.  相似文献   
    200.
    Palaeomagnetism of Holocene lake sediments from north Poland   总被引:1,自引:0,他引:1  
    Summary. Detailed palaeomagnetic investigations of 17 cores of Holocene lake sediments from four lakes in Poland show a pattern of declination variations similar to those found in Lake Windermere, England and in addition a well defined pattern of inclination variations. A total of nine inclination swings are observed compared to five declination swings and their phase relationships are such that both sets of swings cannot be periodic. Exact dating of the palaeomagnetic record is not possible as radiocarbon ages are over 1000 yr older than those deduced from palynological studies. Thermomagnetic and X-ray studies on magnetic concentrates confirm the results of studies of remanence cooling, IRM acquisition and coercivity experiments which are consistent with fine grained magnetite as the main magnetic mineral in the sediments.  相似文献   
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