地磁1年周期变化的响应函数     

陈伯舫 《地震地磁观测与研究》1997,18(2):40-44

用通日月均值减去夜均值计算的月均值资料和Ｓｏｍｐｉ谱分析法分析了１４个台站的北向分量１年周期变化的振幅向相位，时段为１９８４－１９８８年。分析结果显示用Ｐ＾０ｎ（ｄｎｄ＝１，…，６）复合模式的估算的Ｃ值较合理。各台的Ｃ值比较一致。  相似文献   

甘肃巴谢剖面黄土-古土壤的光释光测年研究   总被引：2，自引：0，他引：2  

陈杰  卢演俦  尹功明  刘爱国  孙瑛杰  胡碧茹 《地球学报》1997,18(Z1):239-241

光释光（OSL）测年是测定第四纪沉积物年龄的一种新技术。它通过单色光束激发使晶体中储存的电离辐射能释放出来。与热释光（TL）测年相比，OSL测年可以不考虑残留的OSL信号，而且测量具有简便、迅速且准确等优点。本文用细颗粒光释光技术对甘肃巴谢剖面的黄土-古土壤进行了测定，其测年结果与14C测年结果相吻合。这表明，光释光是一项极潜力的年代学技术。  相似文献   

A mixed finite element method for Hele-Shaw cell equations     

J. M. Guevara-Jordan  J. Glimm 《Computational Geosciences》1997,1(1):35-58

A new numerical method to solve the system of equations describing two phase flow in a Hele-Shaw cell is presented. It combines a mixed finite element method, the method of subtraction of the singularity and a front tracking grid in a single computational strategy. This choice of discretization techniques is well motivated by the difficulties present in the system of equations and the physics of the problem. The new method was tested against analytical solutions and also by solving the Saffman–Taylor viscous fingering problem for finite and infinite mobility ratios. In both cases convergence under mesh refinement is achieved for the fingers developed from an initial sinusoidal interface. Finger splitting is observed for low values of the surface tension and high mobility ratio. Different explanations, based in our results, are provided for this phenomenon. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

一种简单方便的防拷贝程序设计方法——识别计算机的C语言程序设计     

王华军  罗延钟 《物探化探计算技术》1997,(2)

本文主要讨论一种特殊的Ｃ语言程序设计方法，这种程序能有效地对自身的关键模块加密，并能在运行时完成动态解密。该方法主要利用了“硬盘分区表”和最初安装在硬盘中程序自身的位置等信息，采用伪随机数加密法来实现。因所设计的程序具有识别计算机的能力，能有效地防止非法复制，从而保护软件制作者的知识产权和经济利益  相似文献   

地幔流体的前缘研究   总被引：19，自引：8，他引：19  

曹荣龙 《地学前缘》1996,3(4):161-171

地幔流体是与地幔环境处于平衡的气体和挥发分。其主要化学组分为碳、氢、氧、氮、硫（ＣＨＯＮＳ）。它以富于地球内部原始组分为特征，但也包含部分再循环组分。地幔挥发分在弱还原条件下主要为ＣＯ２－Ｈ２Ｏ，强还原环境则以ＣＨ４－Ｈ２Ｏ－Ｈ２为主。地幔流体地球化学的重要性质为：（１）易溶于硅酸盐熔体；（２）净化作用；（３）再沉淀作用。近年来，有关地幔流体中稀有气体和挥发分的起源、分布及同位素组成等前缘领域的研究已取得重要进展。当前拟优先探索的问题包括气体裂化与金刚石成因，非生物成因地幔烃，地幔流体与成矿作用，以及地幔挥发分注入与地壳重熔等。  相似文献   

一种新的、快速的碳、氮、硫同位素测定手段──EA－IRMS连线分析技术   总被引：2，自引：0，他引：2  

储雪蕾 《矿物岩石地球化学通报》1996,(4)

一种新的、快速的碳、氮、硫同位素测定手段──ＥＡ－ＩＲＭＳ连线分析技术储雪蕾（中国科学院地质研究所，北京１０００２９）关键词元素分析仪－同位素比值质谱仪，连线分析碳，氮，硫同位素碳、氮、硫三种元素的稳定同位素在地学、生态学、环境科学等领域受到了重视，...  相似文献   

多电极直流探测系统及其应用效果   总被引：2，自引：0，他引：2  

李志武  周燕云  刘永东  贺宁波 《物探与化探》1996,20(6):461-470,473

本文介绍地质矿产部机电所研制的多电极直流探测系统的主要技术性能,硬件和软件设计特点,数据处理软件的配置以及在不同领域勘探应用实例。  相似文献   

焦作矿区电法探测导,含水构造的效果     

张萍芳  高建中 《煤田地质与勘探》1997,25(5):40-43

应用直流电法仪在井下进行了工作面巷道底板电测深和掘进头超前探测，查清了工作面底板水层的富水性和掘进头前头的地质构造及含水情况。目前，大部分探测结果已得到生产实践的证实。  相似文献   

Solar modulation of cosmogenic nuclide production over the last millennium: comparison between C and Be records     

Edouard Bard  Grant M. Raisbeck  Franoise Yiou  Jean Jouzel 《Earth and Planetary Science Letters》1997,150(3-4):453-462

For about the last 30 years it has been recognized that the high frequency component of the tree rings ¹⁴C/¹²C record is dominated by the modulation of the cosmic ray flux by the solar wind. In particular, it has been demonstrated that the three most recent periods of low sunspot occurrence were characterized by high values of atmospheric ¹⁴C/¹²C. During the last millennium other periods of high ¹⁴C/¹²C values were observed but their solar origin is still debatable. In the present work we compare these fluctuations with an independent record of cosmogenic ¹⁰Be measured in ice from the South Pole to check the solar origin of the observed ¹⁴C/¹²C variations. In order to compare quantitatively the results obtained on ¹⁰Be and ¹⁴C, it is necessary to take into account the different behaviour of these two cosmogenic isotopes, and especially the damping effect of the carbon cycle in the case of ¹⁴C. As an input to a 12-box numerical model we used the relative fluctuations of the ¹⁰Be concentrations record measured in South Pole ice and converted it into a synthetic ¹⁴C record. We took into account the fact that ¹⁰Be modulation is enhanced in polar regions due to the orientation of the geomagnetic field. As expected, the fluctuations of the modelled ¹⁴C record are much smaller (a factor of 20) than those observed for the raw ¹⁰Be record. In addition, the variations are smoother and shifted in time by a few decades. The ¹⁰Be-based ¹⁴C variations closely resemble the ¹⁴C measurements obtained on tree rings (R = 0.81). In particular, it is easy to identify periods of maximal ¹⁴C/¹²C which correspond to solar activity minima centred at about 1060, 1320 (Wolf), 1500 (Spörer), 1690 (Maunder) and 1820 (Dalton) yr A.D. Cross-correlation calculations suggest that there is no significant lag between the ¹⁰Be-based ¹⁴C and the tree-ring ¹⁴C records. Our study strongly suggests the dominance of the solar modulation on the cosmonuclide production variations during the last millennium.  相似文献   

杭州地区石笋稳定同位素古气候探索   总被引：1，自引：0，他引：1  

王兆荣  支霞臣  张汉昌 《沉积学报》1997,(1)

用１４Ｃ测年技术和稳定同位素地球化学古温度方法，对浙江省临安瑞晶洞穴的石笋进行了１４Ｃ的测年和碳、氢、氧同位素测试，获得５～１万年间杭州地区古气候演化记录、该记录表明，在５～１万年间有三次较明显的周期性古温度变化，最高温度为１４．９℃，最低温度为６．６℃，最大温差为８℃左右，平均温差３～５℃。这段时期正处在大理冰期后期，但大理冰期并不是一个持续的低温阶段，它至少有３次温度波动。与我们获得的石笋同位素古温度相一致。另外，我们将５～１万年间杭州地区古气候变化与同期东南沿海的海平面变化进行了对比，在时间上也较为吻合，也就是温度上升、海平面也上升，温度下降、海平面也随之下降  相似文献