Geophysical investigations of the Wairakei Field

Geophysical studies of the Wairakei sector of the Wairakei–Tauhara geothermal system started shortly after exploration drilling began in the early 1950s. These investigations have made a major contribution in defining the boundary of geothermal systems and understanding the changes that have occurred in the reservoir as a result of fluid production. The most successful tools have been electrical resistivity methods for delineating the field, while microgravity, heat loss and groundwater level monitoring surveys were useful to interpret production-induced changes. Seismic, gravity and magnetic surveys had only limited success.     

数据库管理系统中数据异常体系化定义与分类

数据异常尚没有统一的定义,其含义是指可能破坏数据库一致性状态的特定数据操作模式.已知的数据异常有脏写、脏读、不可重复读、幻读、丢失更新、读偏序和写偏序等.为了提高并发控制算法的效率,数据异常也被用于定义隔离级别,采用较弱的隔离级别以提高事务处理系统的效率.体系化地研究了数据异常以及对应的隔离级别,发现了22种未被其他文献报告过的新的数据异常,并对全部数据异常进行分类.基于数据异常的分类,提出了新的且不同粒度的隔离级别体系,揭示基于数据异常定义隔离级别的规律,使得对于数据异常和隔离级别等相关概念的认知可以更加简明.     

黑龙江省鹿鸣钼矿地球物理特征及异常模型

斑岩型铜钼矿床由于具有规模大、埋藏浅、易于开采的特点,成为铜、钼金属的主要来源,一直是地质找矿的主要方向,因此研究斑岩型铜、钼矿勘查找矿方法具有十分重要的意义。以鹿鸣钼矿（开展了详查和勘探工作的典型斑岩型矿床）为例,利用重磁、激电、高密度电阻率以及可控源音频大地电磁测深（Controlled Source Audi-frequency Magnetotelluric,CSAMT）等多种地球物理勘探方法,结合矿区矿体部位的矿床地质特征,系统分析了矿区物探异常特征,建立了矿区地质地球物理模型,并给出了寻找该类型矿床的地球物理勘查方法和实施步骤,为该地区以及类似地区的找矿工作提供参考。     

Ultrasonic investigation of elastic phase transitions in betaine compounds

The results of ultrasonic velocity and attenuation measurements in deuterated betaine phosphite (DBPI) and its compounds near the antiferrodistortive phase transition (PT) are presented for X, Y and Z crystallographic directions. For longitudinal ultrasonic modes propagating along X and Z axes in DBPI the critical slowing down in ultrasonic velocity and attenuation maxima have been observed at PT. Instead, we have not found the critical elastic anomalies for longitudinal Y mode. In DBP crystals the elastic anomalies appeared at PT for all X, Y and Z modes. In solid solution DBP/DBPI the orientation dependencies of elastic anomalies varied from those of DBPI to those of DBP. The phase diagram has been obtained from ultrasonic data. The experimental data in the antiferrodistortive phase have been interpreted in terms of the mean field Landau theory. It is shown that the phase transitions are very close to the tricritical ones.     

根据磁异常确定磁性体上顶埋深的几种反演方法——以尕林格矿区磁测资料解释为例

根据磁异常确定磁性体上顶埋深是磁法勘探中寻找磁性物体及磁性矿床的重要问题之一。笔者总结了4种用磁异常确定磁性体上顶埋深的反演方法,它们是切线法、欧拉法、功率谱法、磁化强度成像法。本文首先将这4种方法用于板状体模型的反演,反演深度与板状体实际深度一致。然后,将它们应用于青海省尕林格矿区地面高精度磁测资料的反演解释,以勘查被广厚的第四纪砂砾沉积覆盖的磁铁矿,取得较好找矿效果。     

ODA-IPNMF: 一种在线全网络流量异常检测方法

为实时、高效地检测网络流量异常,提出一种基于增量投影非负矩阵分解(IPNMF)的全网络流量异常检测方法(ODA-IPNMF).提出一种增量投影非负矩阵算法,该算法不仅具有与PCA相同的表达形式,还能以增量的方式构建正常子空间和异常子空间,进而利用Shewhart控制图实现全网络流量异常的在线检测.理论分析表明,该方法计算开销远小于NMF-NAD,具有更高的实用价值;模拟网络数据以及实测网络数据实验表明,基于NMF异常检测方法(NMF-NAD和ODAIPNMF)的检测性能优于PCA方法;本文所提ODA-IPNMF与NMF-NAD网络异常检测效果相当,且可在线检测网络异常.     

对几起500kV变电站异常情况和事故的分析及处理

500kV变电站一般均为地区电网的中枢点。在发生异常情况或事故时若处理不当,极易造成大面积停电事故的发生,甚至威胁整个系统的安全。本文从发生在500kV敬亭变电站的几起异常情况和事故着手,分析了事故发生的原因以及处理情况,体现了迅速准确的分析处理各类异常情况和事故对于变电站安全稳定运行的重要性。     

云南宋家坡斑岩铜矿地电化学异常特征及机制

宋家坡斑岩铜矿地电提取异常特征是Ｚｎ＞Ｃｕ＞Ｐｂ,呈现明显的电化学型异常标志。模拟实验结果得出,斑岩铜矿体具有较强的电化学溶解能力,斑岩铜矿电导率异常呈低背景,高强度,典型“兔耳状”形态分布,其成分组成主要是ＳＯ２－４,ＨＣＯ－３,Ｍｇ２＋。     

MAPGIS在地球物理勘查制图中的应用

MAPGIS是我国自主研究开发的大型基础地理信息系统软件平台,具有机助制图、图形编辑和图形处理等多种功能,是我国地质行业数字化制图的首选工具。本文结合工作实例,介绍了MAPGIS在地球物理勘查中的数字制图方法。     

Normal state of short coherence length superconductors: Qualitative differences between spin and charge correlations

The temperature scaleT* at which the amplitude of the order parameter is formed is in general much higher than theT _c at which phase coherence is established in short coherence length superconductors. Using quantum Monte Carlo simulations for the attractive Hubbard model we show that for a degenerate 2D system the spin and charge responses show qualitatively different behavior in the normal state in the temperature rangeT _c <T<T*. We find that _s is stronglyT-dependent whiledn/d is independent ofT. A pseudo-gap develops in the one-particle density of states and leads to anomalous behavior of the NMR relaxation rate 1/T ₁ T _s (T) characteristic of spin gap behavior in the high-T _c materials.