薄层CT对肺内结节性病变的诊断价值

本文利用薄层CT扫描技术,对支气管微细结构和改变,对肺内结节性病变大小、边缘、钙化、CT值及定位进行观察,分析了炎性纵隔淋已结肿大的特点。对肺内不肯定结节行CT 导引下活检,可明确诊断。切凹征、胸膜牵拉征、小泡征、小蜘蛛状改变、血管聚集等对肺癌的定性诊断具有重要价值。     

Pseudo-Static Elasto-Plastic Cyclic Creep Model and Cyclic Stability of Offshore Soft Foundation

The accumulative shear deformation of soft clays under cyclic loads is considered as pseudo-staticcreep.A pseudo-static elasto-plastic cyclic creep model is developed based on the visco-elasto-plastic theory.Theparameters in the model are determined by cyclic triaxial soil tests.A method for analyzing the stability of offshoresoft foundation under wave loads is given by combining the model with pseudo-static creep analysis.An exampleis analyzed by the method.The results show that the horizontal and vertical stability of foundations under waveloads can be analyzed by it and the analytical results are qualitatively consistent with the observed failure modes ofshallow foundations.     

Prediction of Siltation in the Downstream Approach Channel of Tidal Locks

Silt deposition occurs in the downstream approach,channel of the tidal lock as in a closed channelor excavated dock basin.It is often difficult to calculate or predict siltation because of complex flow and sedi-ment conditions and many other affecting factors.In this paper,the characteristics of flow movement in theapproach channel(including its mouth)of the tidal lock are analyzed,the basic laws of sediment movementand siltation mechanism are investigated,the conditions for three types of siltation(circumfluence siltation,density flow siltation and slow flow siltation)are discussed,and corresponding calculating formulas are pro-posed.A practical example shows that the difference between measured and calculated results is small,indi-cating that the present calculating methods could be used in design and management of practical engineeringprojects.     

Three-dimensional saltating processes of multiple sediment particles

The purpose of this study was to investigate the interacting mechanism between the saltating particles near a channel bed. A three-dimensional real-time flow visualization technique was developed to measure the interparticle collision behaviors during the saltating process. Based on the experimental data, the distribution of the collision points was found to be symmetric. This confirms the assumption that the projections of the collision points onto the reasonable plane are uniformly distributed. A three-dimensional saltating model was also developed. This model produced satisfactory results. The model is able to simulate the continuous saltating trajectories of several particles. The simulated dimensionless saltating height, longitudinal and vertical saltation velocity components were found to increase as the dimensionless particle diameter and the dimensionless flow transport capacity parameter increase, while the simulated lateral saltation velocity component varies inversely with the dimensionless flow transport capacity parameter. A regression equation for the bed load transport rate was also obtained.     

黔东南地区褶皱构造样式及其断层突破模式

黔东南地区发育隔槽式褶皱组合和逆冲断层.通过对褶皱和地层的平面展布、断层的产状和性质以及滑脱层的分析, 结合典型地震剖面解释和平衡剖面恢复, 对黔东南地区构造特征及其成因进行了探讨.结果表明, 隔槽式褶皱的发育不仅与滑脱深度和剥蚀差异有关, 而且与逆冲断层的推覆距离、逆冲断层的产状、断坪断坡长度比、断层突破方式和多层次滑脱等方面存在着密切联系.结合区域构造演化和推覆距离的制约, 建立了黔东南地区的隔槽式褶皱构造样式的几何学和运动学模型, 确定其主要影响因素是断坪断坡长度比较小、多种方式断层突破和多层次滑脱.      

The Statistical Relation of Shear Velocity with Soil Properties

Shear velocity is an important index for evaluating soil dynamic properties of the site.In thispaper,the statistical relation of shear velocity with soil properties is set up by statistical analysis of shearvelocities and relevant soil properties measured in Tianjin and Shanghai.The obtained formula has somereferential value for the evaluation and classification of the site in offshore areas of China.     

矿产预测理论——区域成矿学向矿产勘查延伸的理论体系

矿产预测理论研究始于20世纪50年代,在近60年的预测实践中,始终是研究的热门课题。我国学者在全国第一、二轮区划实践和相关研究成果基础上,完善了矿产预测理论的基本内容,形成矿产预测的理论体系,推动了区域成矿学向矿产勘查延伸新领域的探索。矿产预测理论概括为矿床成矿作用“异相定位”预测理论;矿床成矿系列“缺位”预测理论;多元信息“类比-求同”预测理论和地质体“对等求异”预测理论。认为成矿作用的“异相定位和矿床成矿系列”缺位预测理论是矿产预测的地质理论依据,又是对成矿学理论的补充;多元信息“类比-求同”理论是传统的预测理论,本文赋以新的内含;地质体“对等求异”理论补充了“类比-求同”理论的不足,是前3项理论内容无可比拟的。矿产预测理论已受矿产勘查实践的检验,证明是有效的,在当前已成为提高矿产预测成果准确性和勘查效益的科学依据。     

Perturbed solution of sea-air oscillator for the El Nino/ La Nina-Southern Oscillation mechanism

A class of coupled system of the El Nino/La Nina-Southern Oscillation (ENSO) mechanism is studied. Using the perturbed theory, the asymptotic expansions of the solution for ENSO model are obtained and the asymptotic behavior of solution for corresponding problem is considered.     

Non-Linear Response of Tethers Subjected to Parametric Excitation in Submerged Floating Tunnels

For the study of the non-linear response of inclined tethers subjected to parametric excitation in submerged floating tunnels,a theoretical model for coupled tube-tether vibration is developed.Upon the assumption that the static equilibrium position of the tether is a quadratic parabola,the governing differential equations of the tether motion are derived by use of the Hamilton principle.An approximate numerical solution is obtained by use of Galerkin method and Runge-kutta method.The results show that,when the static equilibrimn position of the tether is assumed to be a quadratic parabola,the tether sag effect on its vibration may be reflected;the tether sag results in the asymmetry of tether vibration amplitude;for the reduction of the tether amplitude,the buoyant unit weight of the tether should approach to zero as far as possible during the design.     

赣南大吉山五里亭岩体的锆石ELA-ICP-MS定年及其与钨成矿关系的新认识

大吉山是南岭地区一个著名的大型钨多金属矿床,五里亭岩体是矿区出露规模最大的火成岩体,岩性为中粗粒似斑状黑云母二长花岗岩。锆石 ELA-ICP-MS 定年结果表明其形成年龄为 237.5±4.8 Ma,属印支期岩浆活动的产物。与南岭地区典型钨多金属矿床成矿岩体相比,五里亭岩体贫硅,富钙、镁、铁,Rb/Sr、Rb/Ba 和 U/Th 比值低,K/Rb 比值高,铕负异常不显著,分异指数低,尚未达到矿化岩体的分异演化程度,不具备矿化岩体的地球化学特征。元素—同位素综合示踪显示区内白云母碱长花岗岩为五里亭岩体经高度分异演化的产物,它与钨多金属矿成矿直接有关。矿区范围内出露的闪长岩起源于地幔,这一岩浆侵位所引起的高热场环境有利于花岗质岩石的形成与演化,对成矿具有重要的意义。