钻孔方位角的研究

去年九月左右,为了支援鞍钢提先完成基本建设的地质勘探任务,我院地质矿产勘察系四年级全体同学,赶赴鞍钢的附属矿山,×××铁矿,做矿山地质精查工作,这对我们缺乏实际操作经验的学生来说,是一件生疏的事情,但经过一个短期的工作与学习,我们大家很快的就掌握了一些现场的实际操作,但也遇到了一些困难,例     

我的一点看法——浅谈开创气象工作新局面的认识、设想和做法

党的十二大,确定了全面开创社会主义现代化建设新局面而奋斗的宏伟纲领,仅仅半年多时间,各行各业在党的正确路线指引下,乘风破浪,奋勇前进。面对日新月异的 新形势,我们气象部门怎么办?桂林地区的同志想了很久,议过多次,提出了一些观点和措施。新时期的总任务使我们深深感到:振兴中华,匹夫有责,人人都要为开创新局     

用增强显示红外云图测梅雨锋强降水的探讨

用卫星云图估计降水,可以弥补地面雨量计和雷达测雨之不足,是测量降水的可行的方法之一。它可以估计连续性降水,还可以进行强对流降水的定量估计,在农业和水文等方面具有很大的实际应用价值。本文用增强红外云图对梅雨锋上的中尺度(或中间尺度)对流云团云顶各灰阶数及其面积与相应覆盖区的地面降水量之间的关系进行了统计分析,提出了定量估计梅雨锋强降水的模式 其中P_n为每小时降水量,n为灰阶数,S_ n为灰阶面积,a_0、a_1、a_2是用最小二乘法求     

Analytical and numerical models to explain steady rates of spring flow

Flow from some springs in former glacial lakebeds of the Upper Midwest is extremely steady throughout the year and does not increase significantly after precipitation events or seasonal recharge. Analytical and simplified numerical models of spring systems were used to determine whether preferential ground water flow through high-permeability features in shallow sandstone aquifers could produce typical values of spring discharge and the unusually steady rates of spring flow. The analytical model is based on a one-dimensional solution for periodic ground water flow. Solutions to this model suggest that it is unlikely that a periodic forcing due to seasonal variations in areal recharge would propagate to springs in a setting where high-permeability features exist. The analytical model shows that the effective length of the aquifer, or the length of flowpaths to a spring, and the total transmissivity of the aquifer have the greatest potential to impact the nature of spring flow in this setting. The numerical models show that high-permeability features can influence the magnitude of spring flow and the results demonstrate that the lengths of ground water flowpaths increase when high-permeability features are explicitly modeled, thus decreasing the likelihood for temporal variations in spring flow.     

Changes in zooxanthellae density,morphology, and mitotic index in hermatypic corals and anemones exposed to cyanide

Sodium cyanide (NaCN) is widely used for the capture of reef fish throughout Southeast Asia and causes extensive fish mortality, but the effect of NaCN on reef corals remains debated. To document the impact of cyanide exposure on corals, the species Acropora millepora, Goniopora sp., Favites abdita, Trachyphyllia geoffrio, Plerogyra sp., Heliofungia actinformis, Euphyllia divisa, and Scarophyton sp., and the sea anemone Aiptasia pallida were exposed to varying concentrations of cyanide for varying time periods. Corals were exposed to 50, 100, 300, and 600 mg/l of cyanide ion (CN(-)) for 1-2 min (in seawater, the CN(-) forms hydrocyanic acid). These concentrations are much lower than those reportedly used by fish collectors. Exposed corals and anemones immediately retracted their tentacles and mesenterial filaments, and discharged copious amounts of mucus containing zooxanthellae. Gel electrophoreses techniques found changes in protein expression in both zooxanthellae and host tissue. Corals and anemones exposed to cyanide showed an immediate increase in mitotic cell division of their zooxenthellae, and a decrease in zooxanthellae density. In contrast, zooxanthellae cell division and density remained constant in controls. Histopathological changes included gastrodermal disruption, mesogleal degradation, and increased mucus in coral tissues. Zooxanthellae showed pigment loss, swelling, and deformation. Mortality occurred at all exposure levels. Exposed specimens experienced an increase in the ratio of gram-negative to gram-positive bacteria on the coral surface. The results demonstrate that exposure cyanide causes mortality to corals and anemones, even when applied at lower levels than that used by fish collectors. Even brief exposure to cyanide caused slow-acting and long-term damage to corals and their zooxanthellae.     

Assessment of the aesthetic quality of a selection of beaches in the Firth of Forth,Scotland

The aesthetic quality of fourteen beaches in the Firth of Forth, Scotland was surveyed between May and July 2002 using a protocol designed by the UK's National Aquatic Litter Group (NALG). Local authority beach cleaning regimes influence the amount of litter found on beaches. Frequent and thorough beach cleaning is necessary to maintain high aesthetic standards. Bathing and amenity beaches achieved higher aesthetic quality than non-bathing and non-amenity beaches. The aesthetic quality of rural and urban beaches was very similar. The NALG protocol appears more complicated to use than other beach litter surveys. However, the classification system generates results that are easily interpreted by the general public. Furthermore, the NALG protocol could be combined with coastal zone management plans as a useful environmental performance indicator.     

贵州百花湖分层晚期有机质降解过程与溶解N2O循环

百花湖是一个具有季节性分层的富营养小型湖泊,在秋季湖水倒转期经常发生水质恶化事件,碳氮循环出现异常。文章研究特选择在秋初,湖泊分层开始消失时,测定了湖水中不同深度的N₂O,CH₄,CO₂,有机和无机碳同位素以及其他化学参数变化。结果发现:采样时百花湖在约6m和16m深度附近出现了两个温度不连续层(SDL和PDL),并影响到有机颗粒的沉降和分解。相对而言,有较多的有机质在这两个层内发生降解,但降解的途径有所不同,上部主要是有氧降解,下部则主要是无氧降解过程。N₂O的产生和消耗与有机质的降解过程完全对应:PDL层以上,ΔN₂O与AOU的线性关系反映了N₂O主要形成于硝化作用;PDL层以下反硝化作用导致N₂O严重不饱和;PDL内位于硝化作用和反硝化作用过渡带的N₂O峰,显然是硝化与反硝化联合作用的结果。PDL层内较大的CH₄浓度变化梯度,说明嗜甲烷细菌可能通过氧化NH+4贡献了部分N₂O。百花湖秋、冬季表层湖水N₂O都是过饱和的,都是大气N₂O的源,依据分子扩散模型计算湖泊N₂O的释放通量在12～14μmol/m·day之间,秋、冬季没有明显的差别。秋季底层湖水的反硝化作用是湖泊N₂O的汇,其消耗通量与表层的释放通量基本相当。     

华南上石炭统船山组中核形石的地质与经济意义

华南上石炭统船山组中普遍发育大量俗称“船山球”的核形石。这种核形石以其分布范围广、数量多、沉积厚度大和特征相似而成为地质历史上一种独特的时装相(Fasion facies)。 笔者通过对华南上石炭统44条地质剖面的实测,800多块光片、薄片的观察及适量的扫描电镜和化学分析发现,这种核形石的内部结构、构造十分复杂,并非过去所认为的属单一的“葛万藻核形石”。根据其形状和动植物的组合,可以区分出许多种类型。含核形石的沉积物主要形成于多滩(岛)的沉积环境中,但核形石也并非以前所说的仅仅出现于单一的滩相环境,它们可以出现于潮下低能带和泻湖。     

盾构隧道衬砌结构受力分析的梁—弹簧系统模型

盾构隧道衬砌结构由若干管片及其间的连接螺栓组成。在其断面受力的工程设计中,目前普遍采用梁-弹簧系统模型来模拟其受力性态。其中,梁可分成直梁和曲梁两类。本文在考虑弹簧刚度的轴向、切向和转动效应的同时,从卡氏（Castigliano）第二定理出发,给出了梁-弹簧模型的矩阵式,并论证了直梁-弹簧模型与曲梁-弹簧模型的一致性关系。在数值模拟计算过程中,还考虑了地层反作用力非线性情形和管片接头转动刚度正、负弯矩时的非对称性问题。