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931.
Traditional formation pressure prediction methods all are based on the formation undercompaction mechanism and the prediction results are obviously low when predicting abnormally high pressure caused by compressional structure overpressure. To eliminate this problem, we propose a new formation pressure prediction method considering compressional structure overpressure as the dominant factor causing abnormally high pressure. First, we establish a model for predicting maximum principal stress, this virtual maximum principal stress is calculated by a double stress field analysis. Then we predict the formation pressure by fitting the maximum principal stress with formation pressure. The real maximum principal stress can be determined by caculating the sum of the virtual maximum principal stresses. Practical application to real data from the A1 and A2 wells in the A gas field shows that this new method has higher accuracy than the traditional equivalent depth method.  相似文献   
932.
This paper reviews the progress of population geography in China since the 1980s. The review results suggest that contrary to the common perception of its invisibility and marginalized status in the field, tremendous progress has been made in population geography in China since the 1980s. Population geographers have made significant contribution to the understanding of a wide range of population issues from geographical perspectives, including migration, urbanization, population distribution, the relationships between population, environment and resources, aging, marriage patterns, and migrants’ crimes, although such contribution often did not appear in the geographical circle. Furthermore, population geographers have played an indispensable role in revitalizing population studies in China and forging its links to human geography, occupying an important position in this multi-disciplinary field. Population geographers’ contribution to the areas of migration and urbanization research has been particularly significant, reflected in their leading roles in these areas’ research. The paper demonstrates that as latecomers in the field after more than 20 years of isolation, population geographers in China have gone through a process of catching up and increasing engagement with developments in social sciences and increasing interaction with social scientists since the 1980s, and have benefited greatly from it; however, there is a tendency for population geography to be increasingly alienated from the main stream human geography, a phenomenon similar to but not exactly the same as Anglo-American geography in the late 1990s and early 2000s. The paper argues that population geography is only half way in the course to forge the links between population studies and human geography, and it needs to return to geographical sciences to strike a healthy balance between the field of population studies and that of human geography, and promote its further development in a multi-disciplinary field.  相似文献   
933.
The problem of separating gravitation from inertia is discussed in very general sense, and the conclusion is positive: man can separate gravitation from inertia, if various observation techniques are applied for. The accelerometer's position problem in satellite gravimetry is investigated, and the additional acceleration effect due to the position error of an instrument as well as the difference between the mass center and the gravity center is explored.  相似文献   
934.
935.
东明县现有389个行政村,65.47万农村人口,17.9万户住户,农村居民点用地面积834.85 hm2,占全县土地总面积的9.13%,占建设用地面积的78%.  相似文献   
936.
南京北郊低空污染气象条件若干特征   总被引:1,自引:0,他引:1  
本文根据南京北郊大厂镇地区实测低空温风资料的统计分析,揭露了该区低空逆温、混合层顶高度、风向、风速、大气稳定度等的铅直分布规律和局地环流的某些特征。  相似文献   
937.
通过对博罗可努断裂精河—阿拉山口段微地貌的实地调查 ,发现该断裂错断精河东南到阿拉山口之间的晚更新世冲洪积扇 ,地表留下了冲沟和山脊同步右旋位错、断层陡坎、断层鼓包、拉分盆地等与断层活动有关的微地貌。精河东南冲洪积扇上大冲沟的最大右旋位移为 50 0m ,平均4 0 0m。断层陡坎上的纹沟右旋位移为 2 6~ 4 0m ,较大级别的纹沟位移可分为 5 7m ,8 3m和 15 3m3组。它们大致为 3的整数倍。实测断层陡坎的高度分别为 1 2m ,2 51m和 3 6 3m ,大致是 1 2的整数倍 ,阿拉山口西南断层的水平位移为 1~ 1 7m ;垂直位移可分为两组 ,一组为 0 55m ,另一组为 1 2~ 1 5m。这些数据可能揭示了该断裂段的特征地震水平位移为 3m ,垂直位移为 1 2m。区域地貌对比和年代学分析得出 ,精河东南冲洪积扇的最后形成时代为距今 7万a左右 ,右旋滑动速率为4 7mm/a。  相似文献   
938.
The Babao River Basin is the "water tower" of the Heihe River Basin.The combination of vulnerable ecosystems and inhospitable natural environments substantially restricts the existence of humans and the sustainable development of society and environment in the Heihe River Basin.Soil temperature(ST) is a critical soil variable that could affect a series of physical,chemical and biological soil processes,which is the guarantee of water conservation and vegetation growth in this region.To measure the temporal variation and spatial pattern of ST fluctuation in the Babao River Basin,fluctuation of ST at various depths were analyzed with ST data at depths of 4,10 and 20 cm using classical statistical methods and permutation entropy.The study results show the following: 1) There are variations of ST at different depths,although ST followed an obvious seasonal law.ST at shallower depths is higher than at deeper depths in summer,and vice versa in winter.The difference of ST between different depths is close to zero when ST is near 5℃ in March or –5℃ in September.2) In spring,ST at the shallower depths becomes higher than at deeper depths as soon as ST is above –5℃;this is reversed in autumn when ST is below 5℃.ST at a soil depth of 4 cm is the first to change,followed by ST at 10 and 20 cm,and the time that ST reaches the same level is delayed for 10–15 days.In chilling and warming seasons,September and February are,respectively,the months when ST at various depths are similar.3) The average PE values of ST for 17 sites at 4 cm are 0.765 in spring > 0.764 in summer > 0.735 in autumn > 0.723 in winter,which implies the complicated degree of fluctuations of ST.4) For the variation of ST at different depths,it appears that Max,Ranges,Average and the Standard Deviation of ST decrease by depth increments in soil.Surface soil is more complicated because ST fluctuation at shallower depths is more pronounced and random.The average PE value of ST for 17sites are 0.863 at a depth of 4 cm > 0.818 at 10 cm > 0.744 at 20 cm.5) For the variation of ST at different elevations,it appears that Max,Ranges,Average,Standard Deviation and ST fluctuation decrease with increasing elevation at the same soil depth.And with the increase of elevation,the decrease rates of Max,Range,Average,Standard Deviation at 4 cm are –0.89℃/100 m,–0.94℃/100 m,–0.43℃/100 m,and –0.25℃/100 m,respectively.In addition,this correlation decreased with the increase of soil depth.6) Significant correlation between PE values of ST at depths of 4,10 and 20 cm can easily be found.This finding implies that temperature can easily be transmitted within soil at depths between 4 and 20 cm.7) For the variation of ST on shady slope and sunny slope sides,it appears that the PE values of ST at 4,10 and 20 cm for 8 sites located on shady slope side are 0.868,0.824 and 0.776,respectively,whereas they are 0.858,0.810 and 0.716 for 9 sites located on sunny slope side.  相似文献   
939.
河南省国际旅游客源市场分析   总被引:5,自引:1,他引:5  
分析了河南省国际旅游客源市场的空间分布结构、境外游客在河南省内的流向特征及三大客源市场的状况,建立了河南省国际旅游客源市场的预测模型,并提出了今后境外旅游客源市场的开拓方向和促销策略。  相似文献   
940.
在中国,尤其在中国西北部地区,树轮年表是古气候信息的一个重要来源.由于某种原因,中国东部地区少有树轮研究工作.该文通过运引ARSTAN程序,建立并研究了山东境内沂山地区的树轮主年表(1750~1992).树轮和气候要素的响应面分析得出沂山地区的树轮生长和温度降水呈非线性相关,因此使用传统方法重建单个气候因子是不合理的.通过响应函数和回归分析,5月至8月份的湿润指数(P/T)被确定为重建对象,该湿润指数值代表了温度和降水对树轮生长的共同影响,且相关性很高,远超过信度检验.利用线性回归方法,获得重建湿润指数的预报方程,用树木年轮年表重建了自1750年以来的沂山地区逐年5月~8月湿润指数的变化.分析了沂山地区湿润指数重建的可靠性.  相似文献   
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