台风“麦莎”的强度对台风前部飑线发展过程影响的研究

对2005年8月5日16时(UTC,下同)至6日00时发生的一次台风前部飑线过程进行了数值模拟,分析表明:台前飑线在母体台风和副高之间的湿区生成。台风为这次台前飑线过程提供了有利的条件,包括强的低空急流输送充沛的水汽,强的不稳定环境产生大的对流有效位能以及强的地表辐合,使得初始的离散的对流单体组织发展形成台前飑线。成熟时期的台前飑线虽然比中纬度和热带飑线的变压强度小,但是具有更强的低层暖湿空气入流,中层的入流范围也更加宽广。敏感性试验结果表明:台风强度越强,其台前飑线的回波强度越强,移动速度更快,生命史也更长。强台风使得低空垂直风切变更大,有利于台前飑线的生成和发展,在台前飑线发展成熟后,低空垂直风切变强度减小,不利于台前飑线的维持,加之低空水汽输送的减少,使其逐渐趋向衰亡。     

鲁西南某2300MW坑口电厂桩基原位试验研究

鲁西南某2300MW坑口电厂地基位于黄河冲积地层中,工程地质性质较差,地基强度不能满足电厂重要建(构)筑物的要求。根据现场的工程地质条件,施工中采用预应力高强混凝土管桩(PHC桩)进行地基处理。本文以鲁西南某2300MW坑口电厂桩基检测工程为实例,首先采用低应变法对桩身质量进行了检测,然后采用高应变试验和静载试验2种方法确定了单桩竖向极限承载力,并对这2种方法的优点、缺点和影响因素进行了分析和对比。得出结论:(1)采用高应变CAPWAP法拟合后的试验结果与单桩竖向静载荷试验结果基本吻合,通过选取合适的桩、土参数模型使高应变试验的结果准确可靠,是切实可行的。(2)在现场条件不允许开展静载试验时,高应变试验可作为静载试验的补充手段对桩基进行检测。(3)当能够获得可靠的高应变试验结果(与静载试验基本吻合)时,可以通过严谨计算对规范法设计方案进行一定程度的调整,以节约成本,但要慎重对待。     

云南兰坪中排李子坪铅锌矿矿床成因

铅锌矿产于下白垩统景星组下段泥质粉砂岩、钙质砂岩和中侏罗统花开左组上段砂岩夹薄层泥灰岩介壳灰岩中,脉状、透镜状、层状、似层状等产出。NNE向断裂的交叉夹持部位的旁侧派生次级断裂及层间破碎带是主要容矿构造,矿床成因为沉积-中低温热液改造构造控矿型。     

任意空间取向TI弹性张量解析表述

本文理论给出任意空间取向TI(ATI)四阶弹性张量的解析表述,其以VTI弹性常数及其简单组合为系数,包括各向同性项、TI对称轴方向矢量分量的二次项和四次项,其中TI对称轴方向矢量可以在固定坐标系定义, 也可以相对三维倾斜界面甚至相对波传播方向.相比四阶张量变换法和Bond变换法,ATI弹性张量能简洁而透明地为本构关系和波动方程提供四阶张量的所有元素. ATI弹性张量能为诸多方面的理论研究提供支撑.     

Mg-vacant structural modules and dilution of the symmetry of hydrous wadsleyite, β-Mg2–xSiH2xO4 with 0.00≤x≤0.25

The crystal structures of the two hydrous wadsleyite crystals with formulae, Mg_1.75SiH_0.50O₄ (0.5H–β) and Mg_1.86SiH_0.28O₄ (0.3H–β) have been analyzed in this study. The single-crystal X-ray diffraction data showed that the unit cells of the 0.3H–β and the 0.5H–β are metrically monoclinic with a slight distortion from the orthorhombic cell but their intensity distributions conform to the orthorhombic symmetry within the limit of experimental errors. The Fourier and the difference Fourier syntheses were calculated. Small but significant Fourier peaks were found at the site, Si2, in a normally vacant tetrahedral void adjacent to Mg3 site as reported for the monoclinic hydrous wadsleyite by Smyth et al.. From the comparison of the hydrous and anhydrous wadsleyite structures, the Mg-vacant structural modules were found to be the building units for the structure of hydrous wadsleyite. The dilution of symmetry from orthorhombic to monoclinic in the hydrous wadsleyite structure is interpreted qualitatively due to lack of mirror perpendicular to the a axis in the module. The mode of arrangement of the Mg-vacant structural modules interprets the symmetry and hydrogen content of the hydrous wadsleyite and gives the structural relationship between hydrous wadsleyite and hydrous ringwoodite. Received: 8 May 1998 / Revised, accepted: 3 October 1998     

陆基远程和超远程无线电导航系统发展现状与趋势

高频电磁环境日益复杂,为了提高定位导航授时(PNT)系统的可靠性,需要研发不依赖于卫星导航的陆基无线电导航系统.陆基无线电导航系统具有工作频率低、发射功率大等特点,可靠性高,不易被干扰,可以作为卫星导航系统的备份,因此,发展建设陆基无线电导航系统对于构建稳健可靠的国家PNT体系、保障国家安全和国民经济的发展具有重要意义.文中就国内外陆基远程及超远程无线电导航系统的发展现状及趋势进行了分析.     

吉林腰英台油田油水分布特征及成因探讨

腰英台油田是东北地区新发现的油田，目前刚开始勘探开发，在勘探开发初期遇到不少问题。其中之一是开采时高含水：就油田的实际油水分布特征进行了分析，分析油水同出的可能原因，认为这是受油藏储层物性及构造幅度和实际油柱高度的影响，由于储层低孔、特低渗。实际构造幅度低，实际油柱高度大多低于油藏产纯油所需的油柱高度，致使油藏大都处于油水过渡带。故开采时多含水，油水同出。根据这一分析，认为进一步的油气勘探重点考虑西部水下冲积扇的有利部位。此处储层物性好，有利于接受更多油源。     

����ԳƷ��ڵ��㶨λ�е�Ӧ��

???GPSα????λ????????????????????μ?????????????λ??????????????ù????????????????????????????????棨???棩?????????????????????????????????α?????????????????????α???????????????????????λ??????????·??????????????????λ???????????????????????????????ν????????????????????????Ч????????λ?????????????????     

Fluid sources for the La Guitarra epithermal deposit (Temascaltepec district, Mexico): Volatile and helium isotope analyses in fluid inclusions

The La Guitarra deposit (Temascaltepec district, South-Central Mexico), belongs to the low/intermediate sulfidation epithermal type, has a polymetallic character although it is currently being mined for Ag and Au. The mineralization shows a polyphasic character and formed through several stages and sub-stages (named I, IIA, IIB, IIC, IID, and III). The previous structural, mineralogical, fluid inclusion and stable isotope studies were used to constrain the selection of samples for volatile and helium isotope analyses portrayed in this study. The N₂/Ar overall range obtained from analytical runs on fluid inclusion volatiles, by means of Quadrupole Mass Spectrometry (QMS), is 0 to 2526, and it ranges 0 to 2526 for stage I, 0 to 1264 for stage IIA, 0 to 1369 for stage IIB, 11 to 2401 for stage IIC, 19 to 324 for stage IID, and 0 to 2526 for stage III. These values, combined with the CO₂/CH₄ ratios, and N₂-He-Ar and N₂-CH₄-Ar relationships, suggest the occurrence of fluids from magmatic, crustal, and shallow meteoric sources in the forming epithermal vein deposit. The helium isotope analyses, obtained by means of Noble Gas Mass Spectrometry, display R/Ra average values between 0.5 and 2, pointing to the occurrence of mantle-derived helium that was relatively diluted or “contaminated” by crustal helium. These volatile analyses, when correlated with the stable isotope data from previous works and He isotope data, show the same distribution of data concerning sources for mineralizing fluids, especially those corresponding to magmatic and crustal sources. Thus, the overall geochemical data from mineralizing fluids are revealed as intrinsically consistent when compared to each other.The three main sources for mineralizing fluids (magmatic, and both deep and shallow meteoric fluids) are accountable at any scale, from stages of mineralization down to specific mineral associations. The volatile and helium isotope data obtained in this paper suggest that the precious metal-bearing mineral associations formed after hydrothermal pulses of predominantly oxidized magmatic fluids, and thus it is likely that precious metals were carried by fluids with such origin. Minerals from base-metal sulfide associations record both crustal and magmatic sources for mineralizing fluids, thus suggesting that base metals could be derived from deep leaching of crustal rocks. At the La Guitarra epithermal deposit there is no evidence for an evolution of mineralizing fluids towards any dominant source. Rather than that, volatile analyses in fluid inclusions suggest that this deposit formed as a pulsing hydrothermal system where each pulse or set of pulses accounts for different compositions of mineralizing fluids.The positive correlation between the relative content of magmatic fluids (high N₂/Ar ratios) and H₂S suggests that the necessary sulfur to carry mostly gold as bisulfide complexes came essentially from magmatic sources. Chlorine necessary to carry silver and base metals was found to be abundant in inclusion fluids and although there is no evidence about its source, it is plausible that it may come from magmatic sources as well.     

中尺度涡冷暖特征的推导

为了从理论上解释中尺度涡旋冷暖性质与涡旋旋转方向的关系,本文基于中尺度涡的几何特征,做出如下假设：中尺度涡具有对称的几何形态,涡旋中海洋要素沿径向具有线性化变化的特征。从原始方程组出发,利用柱坐标系和上述假设条件,略去耗散力,推导出了中尺度涡的一些冷暖特征,论证气旋式中尺度涡对应冷涡和反气旋式中尺度涡对应暖涡的涡旋冷暖特征与部分涡旋的观测不符的现象。结果表明,中心对称的形式可以作为对中尺度涡的几何特征的一个理想的形态近似,在考虑上述假设条件的理想环境下,柱坐标系在研究中尺度涡的几何性质上具有一定的优势。