矢量数据动态存贮方法的研究

本文通过对三种矢量数据动态存贮方法的分析比较，并通过实践，找到一种安全可靠并且比较实用的数据动态存贮方式。     

Climate change and critical thresholds in China’s food security

Identification of ‘critical thresholds’ of temperature increase is an essential task for inform policy decisions on establishing greenhouse gas (GHG) emission targets. We use the A2 (medium-high GHG emission pathway) and B2 (medium-low) climate change scenarios produced by the Regional Climate Model PRECIS, the crop model – CERES, and socio-economic scenarios described by IPCC SRES, to simulate the average yield changes per hectare of three main grain crops (rice, wheat, and maize) at 50 km × 50 km scale. The threshold of food production to temperature increases was analyzed based on the relationship between yield changes and temperature rise, and then food security was discussed corresponding to each IPCC SRES scenario. The results show that without the CO₂ fertilization effect in the analysis, the yield per hectare for the three crops would fall consistently as temperature rises beyond 2.5 ^{^}C; when the CO₂ fertilization effect was included in the simulation, there were no adverse impacts on China’s food production under the projected range of temperature rise (0.9–3.9 ^{^}C). A critical threshold of temperature increase was not found for food production. When the socio-economic scenarios, agricultural technology development and international trade were incorporated in the analysis, China’s internal food production would meet a critical threshold of basic demand (300 kg/capita) while it would not under A2 (no CO₂ fertilization); whereas basic food demand would be satisfied under both A2 and B2, and would even meet a higher food demand threshold required to sustain economic growth (400 kg/capita) under B2, when CO₂ fertilization was considered.     

Isotopic evidence for holocene climatic changes in Bosten Lake, Southern Xinjiang, China

ＩＳＯＴＯＰＩＣＥＶＩＤＥＮＣＥＦＯＲＨＯＬＯＣＥＮＥＣＬＩＭＡＴＩＣＣＨＡＮＧＥＳＩＮＢＯＳＴＥＮＬＡＫＥ,ＳＯＵＴＨＥＲＮＸＩＮＪＩＡＮＧ,ＣＨＩＮＡＺｈｏｎｇＷｅｉ（钟巍）ＸｉｏｎｇＨｅｉｇａｎｇ（熊黑钢）ＤｅｐａｒｔｍｅｎｔｏｆＧｅｏｇｒａｐ...     

辽河油田生物降解原油沥青质热解产物中单体化合物碳同位素组成

生物降解原同在我国分布广泛并且在重油资源中占有一定的比例。本文通过采用单体化合物碳同位素分析技术对取自辽河油田西部凹陷的重油以及它们沥青质组分的热解产物进行单体碳同位素测定,来研究原油沥青质热解产物中正构烷烃单体碳同位素的组成及其一物降解油的指示意义。研究结果表明,沥青质热解产物中正构烷烃组分的单体碳同位素组成可用于生物降解较严重的重油样品进行油／油相比,并且与原油中的正构烷烃单体碳同位素组成的对     

石门雄黄矿一号窿矿体构造及深部找矿研究

通过对湖南石门雄黄矿一号窿矿区构造研究 ,雄黄矿床赋存于燕山期形成的背斜核部 ,背斜与断裂、断裂与断裂的交汇部位。在多种手段综合研究的基础上 ,指出了矿区导矿构造为 EW向的 F1、F3 断裂 ,容矿构造为次级的 NEE、NE、NW、SN向断裂构造 ;提出了本区中生代的三期主要构造应力场 ,其中 SN向主压应力的构造应力场共轭角高值区为雄黄矿体富集地带。矿床受寒武系娄山关群白云岩、奥陶系灰岩和构造的双重控制。认为在一号窿主矿体 NW、SW方向可能存在有隐伏矿体     

平面裂隙参数计算及其对浆液流动的影响分析

利用从层流到紊流的多阶段稳定压水试验的压力－流量曲线反算裂隙张开度、粗糙度及地下水影响半径等裂隙参数。建立了平面裂隙中浆液流动的力学模型,并分析了对浆液流动的影响因素。     

天山第四纪冰川擦痕特征及分布规律

根据冰蚀痕迹的统计数据 ,着重讨论了天山高山地区冰岩界面形成过程和冰川擦痕分布规律。典型的冰碛岩一般有擦面和擦痕。冰川槽谷的横剖面上 ,从侧部向中部 ,擦痕密度逐渐增大 ,槽谷的谷壁向谷底的转折处是擦痕密度由小转大的突变点 (拐点 ) ,反映了磨蚀作用不断增强。而冰坎的擦痕密度则呈现较大的波动。冰坎迎冰面的粗大擦痕密度远比槽谷中的擦痕密度大。羊背石从顶部到侧部 ,擦痕密度由大变小     

Preliminary results of measuring the crustal deformation in Qinghai-Xizang area using GPS technique

GPS repetition measurement tbta in Qinghai-Xizatlg (Tibetan) area in 1992 and 1994 have been used to determine the change rates of seven bascline vectors of Lhasa-Wenquan, etc. It is the first time to obtain the direct observation results of the large-scale crustal horizontal motions in this area. Thesc preliminary results also for the first time provide the direct observation evidence for some important geophysical and geological viewpoints, such as the northward gradual reduce of the effect of the northward push-pressing to Eurasian continent by Indian Plate in the Qinghai-Xizang area, having a southward strike slip movement of the Chuan-Dian diamond block, etc.     

构造应力作用下流体运动的动力学分析——构造流体动力学

本文从流体动力学的基本规律出发,应用渗流力学、岩土力学及弹性力学的理论及方法,推导出了考虑应力状态的可变形介质中流体运动的动力学方程,由该方程可以看出：应力状态是影响流体运动的一个非常重要的因素,它通过３种方式来影响流体的运动,其一是：应力的作用改变介质的渗透性能,从而影响流体运动;其二是：平均正应力的变化速率影响介质的含流体能力,它以源汇项的形式反映在方程中;其三是：应力的作用影响流场的初始状态及边界状态,通过影响定解条件反映在动力学方程中,从而影响运动特征。构造应力场对流体运动的最终影响是这３方面作用     

桥梁健康监测与评估中的静力水准技术研究

近年来,我国的桥梁建设事业发展迅速,在桥梁数量大幅增加的同时,其安全形势却较为严峻,因此,越来越多的人开始重视桥梁运营的安全性及耐久性。桥梁健康监测技术通过对桥梁结构的监控及评估,在桥梁运营状况发生异常时发出预警,能够为桥梁的维护及管理提供科学的指导和依据。而静力水准监测技术与传统的光学水准监测技术相比,具有实时性、高精度、自动化等优点。因此,本文对比研究了不同的静力水准仪,并最终推荐选用磁致伸缩式静力水准仪作为监测的仪器。