钻井中首波的共振与衰减

本文从P波首波的严格割线积分出发,首次给出了揭示其共振与衰减特性的渐近展开式,通过数值计算,对这些公式进行了检验,证明它们与严格解符合的相当好.解析的和数值结果一致表明:首波具有共振特性,频谱是连续的;振幅随源距z按1/z规律衰减;各共振峰幅度随岩石泊松比v的增大按[v/（1-v）]²规律增大.时域计算表明,所谓“滤波效应”正是首波共振激发特性的反映,传播过程中不频散.     

Interpretation of Repulsive Bifurcation of the Kuroshio and Gulf Stream with Classification of Their Branches

Distinctive features of the repulsive bifurcation of Kuroshio and Gulf Stream jets, induced from various observations, have been examined by equations of motion of a 1 1/2 -layer model in natural coordinates, although causes of the bifurcation are discussed little. From the conservation of volume flux through paths above a main thermocline, we have derived the equation M _n K _In + M _s K _Is = 0 for northern (n) and southern (s), steady-state curved jets, just downstream of the bifurcation from a straight jet, where M is momentum flux through the path and K _I, positive for cyclonic deflection of the streamline, is the curvature of a certain intermediate streamline in the laminar path. Assuming concentric streamlines in the curved path, which is narrower than 1–0.5 times the radius of curvature of the center streamline of the path, and symmetric momentum flux through a path element of unit width with respect to the center streamline, we found that K _I approximates to the curvature averaged across the path, relative errors being <0.25−(0.25)². Bifurcation starts with a ‘Big Bang’ and the leading turbulent front of a split jet may be unsteady, but the succeeding laminar part can be regarded as stationary or as translating at a constant velocity, as if frozen. Thus, such features are described by the equation. A provisional classification is given of various warm extrusions along branches of both Streams, all of which exemplify the repulsive bifurcation, except for the mainstreams with very narrow (< 30–40 km) branches, possibly due to misapplication of the model. This revised version was published online in August 2006 with corrections to the Cover Date.     

海南岛港湾演变与工程建设

海南岛沿岸多港湾，主要有3种类型的潮汐汊道型港湾：（1）沙坝-泻湖型潮汐汊道港湾主要分布在东南部海岸，以三亚港最为典型。三亚港原始岸线为基岩港湾海岸，由中生代花岗岩构成。花岗岩风化泥沙充填谷地港湾连成陆地，以沙坝-泻湖体系形式逐渐堆积成海积平原。（2）港湾型潮汐汊道主要分布在海南岛西部，起源于构造断裂带的港湾。其演化的主要因素是河流及海岸侵蚀向湾内供应的沉积物以及巨大的纳潮量形成的潮流动力。消费品流及海岸供沙使纳潮水域淤积，纳潮量相应减少，同时在口门内外形成潮流三角洲（拦门沙浅滩）。（3）溺谷型潮汐汊道主要分布在海南岛北岸、东北岸。其演化过程是：古河口溺谷，沿岸输沙发育海岸沙坝，古河口溺谷逐渐淤积衰退，潮流作用形成 口门外落潮流堆积体及涨潮带入海相细粒物质，使纳潮水域进一步淤浅缩小，目前这类汊道处于发育演化的晚期，接近汊道整体的消亡。     

Seasonal Variations of Water Properties and the Baroclinic Flow Pattern in Toyama Bay under the Influence of the Tsushima Warm Current

The seasonal variations of water properties and the baroclinic flow pattern in the upper layer of Toyama Bay, where the shelf breaks in the passway of the eastward coastal branch of the Tsushima Warm Current, have been examined using temperature and salinity data from 26 local stations collected in the 32 years from 1963 through 1994. The results show that the flow pattern around the bay, as inferred from the distributions of the geopotential anomaly at 300 dbar and saline core water, changes remarkably from summer to autumn. There are two obvious inflows into Toyama Bay in a year. One is the surface inflow of less saline water from east of the Noto Peninsula as the coastal-trapped density-driven flow of the coastal branch during the transition from May to July. In September, this inflow is abruptly weakened by a transient northwestward reversal flow in the intermediate layer around 100 m depth. This reversal flow is accompanied by the temporary shallowness of the pycnoclines inside the bay. At that time, another inflow with more saline water of the year occurs in the intermediate layer. From November until January, this reversal flow disappears and a southeastward passing through-flow gradually intensifies across the bay mouth, accompanied by deepening of the pycnoclines inside the bay. According to our interannual analysis over the 32-year study period, this reversal flow has been a stable seasonal phenomenon, except for only 4 years, in which a local warm region or warm eddy developed just north of the Noto Peninsula.     

碗状钻头在松散地层中叉孔的应用

采用粗径岩心管、水泥封闭等方法在新生界松散层中人为叉孔有时效果不太明显。而碗状钻头人为叉孔成功率高，施工工艺简单，节省了时间，降低了成本。本文结合实例简介了碗状钻头的适用范围。     

Isotopic Characteristics of Mesozoic Au-Ag Polymetallic Ore Deposits in Northern Hebei and Their Ore-Forming Materials Source

It has long been a controversy about the source of ore-forming materials of Au-Ag polymetallic deposits both in metallogenic theory and in ore-searching practice. In terms of a large wealth of the isotopic statistics data from Indosinian-Yanshanian endogenic ore deposits in northern Hebei (generally referring to the areas along the northern part of Taihang Mountains and northern Hebei, the same below) , it is considered that the ore-forming materials came from the deep interior of the Earth, which had migrated through plumes to the Earth surface while ex-perienced multi-stage evolution and then emplaced progressively in favorable structural loci to form ores. Their isotope data show that 559 sulfur isotopic data from 40 ore deposits are, for the most part, within the range of -5‰ -5‰, with a high degree of homogenization, indicating that the sulfur is derived mainly from magma; 200 lead isotope data from 37 ore deposits indi-cate that the ore-forming materials are principally of mantle source though some crust-source ma-terial was involved; 96 oxygen, hydrogen and carbon isotope data from 34 ore deposits illustrate that the ore-forming fluids are dominated by magmatic water while other sources of water would be involved. It may therefore be seen that the formation of endogenic deposits has nothing to do with the strata .     

The role of chemical composition in RR Lyrae pulsationalproperties – I. Periods

We analyse the periods of theoretical radial pulsators, covering the range of total masses, luminosities, effective temperatures and chemical compositions expected for RR Lyrae variables in both galactic fields and globular clusters.
We show that for fixed values of the structural parameters (mass, luminosity and effective temperature), the period of fundamental and first-overtone pulsators is independent of the helium content ( Y ), whereas it slightly increases as the amount of metals ( Z ) increases. Furthermore, we find that the period along the blue edge for first-overtone pulsation is a function of mass, luminosity and helium content, with a marginal dependence on Z .
On these grounds, new linear relations connecting the periods to stellar parameters are derived. Such new relations should allow a more accurate interpretation of the RR Lyrae observed periods and, in particular, they should help in ascertaining the calibration of the mean absolute magnitude of RR Lyrae stars in terms of metal content.     

A search for variable stars in the globular cluster M3

We describe here the results of a photometric time-sequence survey of the globular cluster M3 (NGC 5272), in a search for contact and detached eclipsing binary stars. We have discovered only one likely eclipsing binary and one SX Phe-type star in spite of monitoring 4077 stars with V  < 20.0 and observing 25 blue straggler stars (BSS). The newly identified SX Phe star, V237, shows a light curve with a variable amplitude. Variable V238 shows variability either with a period of 0.49 d or with a period of 0.25 d. On the cluster colour–magnitude diagram, the variable occupies a position a few hundredths of a magnitude to the blue of the base of the red giant branch. V238 is a likely descendant of a binary blue straggler.   As a side result we obtained high-quality data for 42 of the previously known RR Lyrae variables, including 33 of Bailey type ab, seven type c and two double-mode pulsators. We used equations that relate the physical properties of RRc stars to their pulsation periods and Fourier parameters in order to derive masses, luminosities, temperatures and helium parameters for five of the RRc stars. We also tested equations that relate the [Fe/H], M _V and temperature of RRab stars to pulsation period and Fourier parameters. We derived [Fe/H]= −1.42 in good agreement with spectroscopic determinations.     

测绘业面临的若干问题与思考

文章以山东省测绘技术行业为基点,对该行业的现状及存在问题进行了阐述。     

地下河水人工补给洞穴滴水、碳酸盐(钙)沉积特征及景观恢复探讨

岩溶旅游洞穴碳酸盐岩沉积物景观容易受到污染、风化,为了探讨受污损洞穴碳酸盐沉积物的修复方法以确保岩溶旅游洞穴的可持续发展,对广西桂林七星岩No.15支洞距洞口约150 m长洞段的滴水物化指标、现代碳酸盐岩沉积物进行了为期4年的监测分析。结果表明:（1）该洞段的滴水主要源于抽取地下河水的水柜渗漏及降水补给,地下河水和滴水的电导率、[Ca2＋] 、[HCO3-]在4个水文年中的变化趋势基本相同,雨季洞穴滴水电导率、[Ca2＋] 、[HCO3-]等显著降低,降雨稀释效应明显;（2）现代洞穴碳酸盐岩沉积具有明显的季节性变化,雨季洞穴滴水量/速率、碳酸钙沉积速率加快,最大沉积量达0.8 g／半月,洞穴入口约150 m长洞段快速滴水碳酸盐最大沉积量达2～4 g／半月,旱季碳酸盐沉积速率减少,最大沉积量仅为0.4 g／半月;（3）抽取岩溶地下水经由地表补给洞穴滴水可提高滴水的电导率、[Ca2＋] 、[HCO3-]及CaCO3饱和度,促使大量碳酸盐(CaCO3)快速沉积,实现对洞穴受风化、污染景观的修复,新沉积的碳酸钙(CaCO3)还可以将基岩裂隙和洞穴内破损、破裂的钟乳石重新“粘结”起来,利于洞穴的稳定性。