Turning depths of internal tides in the South China Sea inferred from profile data     

Kun Liu  Lianglong Da  Wuhong Guo  Chenglong Liu  Junchuan Sun 《海洋学报(英文版)》2022,41(2):139-146

Theoretically, propagating internal tides in the ocean may reflect at turning depths, where buoyancy frequencies equal tidal frequencies, before colliding with the air-sea interface or rugged bottom topography. Globally, the internal tide lower turning depths（ITLTDs） in the open ocean have been mapped; however, knowledge of the presence of ITLTDs in the South China Sea（SCS） is lacking. In this study, 2 125 high-quality temperature-salinity profiles（including 58 deep-sea hydrographic measurements...  相似文献   

Establishment of digital model for dynamic simulation analysis on hydraulic impact perforator     

WANG Qing-yan  YIN Kun  CHEN Bao-yi  JI Sheng-li College of Construction Engineering  Jilin University  Changchun  Jilin  China 《东北亚地学研究》2005,(Z1)

Hydraulic impact perforator is powerful tools for trenchless project. It has advantages in cabinet structure, low cost, long life and easy protected. Compared with pneumatic DTH, the hydraulic impact spear worked under high pressure and using uncompressible fluid thusgreater impact energy and higher efficiency can be supported. The authors founded the dynamic simulation model of HDI-146 hydraulic impact spear. The project for solving the differential equation was suggested also. By means of virtual machine technology, the dynamic mechanism of HDI-146 can be explored and tutoring us to optimize the structural parameters can be made.  相似文献   

Analysis of Wave Loads on A Semi-Submersible Platform   总被引：10，自引：0，他引：10  

QIAN  Kun 《中国海洋工程》2002,16(3):395-406

For the global and structural fatigue strength analysis of a semi-submersible platform, wave loads under design conditions are calculated by use of the three-dimensional boundary element method. Methods for calculating the forward-speed free-surface Green function are discussed and a computer program with this Green function is developed. According to the special rules, the wave loads under several typical design conditions of the platform are calculated. The maximum vertical bending moment, torsion moment and horizontal split force are determined from a series of contour maps of wave loads for the wave period of 5 to 18 seconds at a certain interval and the wave phase of 0°to 360°at a certain interval. The wave height is determined by the function of wave period with a given exceedance probability. The maximum wave loads under the combination of wave parameters are used as the input of hydrodynamic pressure in the three-dimensional finite element analysis process. The transfer functions of wave loads  相似文献   

Scour of the Seabed Under A Pipeline in Oscillating Flow   总被引：3，自引：0，他引：3  

PU  Qun 《中国海洋工程》2001,(1):129-138

The scour of the seabed under a pipeline is studied experimentally in this paper. Tests are carried out in a U-shaped oscillatory water tunnel with a box imbedded in the bottom of the test section. By use of the standard sand, clay and plastic grain as the seabed material, the influence of the bed material on the scour is studied. The relationship between the critical initial gap-to-diameter ratio above which no scour occurs and the parameters of the oscillating flow is obtained. The self-burial phenomenon, which occurs for the pipeline not fixed to two sidewalls of the test section, is not observed for the fixed pipeline. The effect of the pipe on sand wave formation is discussed. The maximum equilibrium scour depths for different initial gap-to-diameter ratios, different Kc numbers and different bed sands are also given in this paper.  相似文献   

Establishment of digital model for dynamic simulation analysis on hydraulic impact perforator     

WANG Qing-yan YIN Kun CHEN Bao-yi JI Sheng-li 《东北亚地学研究》2005,8(1):138-141

Hydraulic impact perforator is powerful tools for trenchless project. It has advantages in cabinet structure, low cost, long life and easy protected. Compared with pneumatic DTH, the hydraulic impact spear worked under high pressure and using uncompressible fluid thusgreater impact energy and higher efficiency can be supported. The authors founded the dynamic simulation model of HDI-146 hydraulic impact spear. The project for solving the differential equation was suggested also. By means of virtual machine technology, the dynamic mechanism of HDI-146 can be explored and tutoring us to optimize the structural parameters can be made.  相似文献   

A 3D magnetotelluric inversion system with a theoretical assessment in oil and gas exploration     

ZHANG Kun  YAN Jiayong 《《地质学报》英文版》2015,89(Z1):434-436

<正>1 Introduction Magnetotelluric(MT)is a geophysics method for oil exploration,which measures the surface orthogonal electric and magnetic fields base on the electromagnetic induction and natural electromagnetic fields.The data process and inversion methods are developed.The static shift effect is a very common phenomenon in  相似文献   

Magma Chamber Process of Post-collisional Magmatism: Insight from Textural and Elemental Characteristics of Plagioclase from the Tatun Volcanic Group, Northern Taiwan Volcanic Zone     

ZHANG Xi  GUO Kun  ZHANG Yu  LAI Zhiqing  JIANG Shulong  JIANG Wenpeng  LI Jingbo 《《地质学报》英文版》2022,96(5):1587-1599

The Taiwan mountain belt, one of the youngest orogenies in the world, is caused by the collision of the Luzon arc with the Eurasian margin, which leads to post-collisional extension and magmatism in the Northern Taiwan Volcanic Zone (NTVZ). The magma chamber process in this region has not previously been elucidated in detail. In this paper, the textural and compositional features of plagioclase phenocrysts in basalt from the Tatun Volcanic Group (TTVG) were studied to restrict the dynamics of magma system. Results show that the magma melts in TTVG are mainly sourced from the underlying MORB-like mantle wedge but influenced by incorporation of subduction components, causing the elevated Sr/Y and Ba/Y ratios in magma melts. The subduction components are mainly transported in the form of sediment melt. The plagioclase phenocrysts in the TTVG volcanic rocks are generally coarsely core-sieved with a clear rim. The An contents in the rims of plagioclase are much lower than those of cores, and elevated FeO concentrations are detected in the plagioclase rims. We propose there exists a double-layer magma chamber in this region. The core of the plagioclase was crystalized in the deeper quiescent magma chamber (~21 km), which was subsequently partially dissolved during the ascent of magma melt under H2O-undersaturated condition, forming the typical coarsely sieved texture and synneusis. When this crystal-rich melt migrates into the shallower chamber, water saturation is reached and more sodic plagioclase formed as the rim of phenocryst. Due to the considerably higher fO2 in the shallow chamber than in the deeper one, and the distribution of Fe between plagioclase and melt positively correlates with fO2, the FeO content in the plagioclase rim elevates in conjunction with increasing fO2.  相似文献   

Petroleum Retention,Intraformational Migration and Segmented Accumulation within the Organic-rich Shale in the Cretaceous Qingshankou Formation of the Gulong Sag,Songliao Basin,Northeast China     

HUANGFU Yuhui  ZHANG Jinyou  ZHANG Shuichang  WANG Xiaomei  HE Kun  GUAN Ping  ZHANG Huanxu  ZHANG Bin  WANG Huajian 《《地质学报》英文版》2023,97(5):1568-1586

In this study, organic geochemical and petrological analyses were conducted on 111 shale samples from a well to understand the retention, intraformational migration and segmented accumulation(shale oil enrichment in different intervals is unconnected) features of shale oil within the organic-rich shale in the Qingshankou Formation of the Gulong Sag. Our study shows that retained petroleum characteristics in the investigated succession are mainly influenced by three factors: organic richness, int...  相似文献   

Characteristics of sedimentation and channel adjustment linked to the Three Gorges Reservoir     

Xiaoya Tang  Sichen Tong  Guoxian Huang  Guangxiang Xu  Xinghua Li  Kun Lei  Shiming Yao 《国际泥沙研究》2021,36(2):177-189

Construction of large dams is attractive because of their great benefits in flood control,hydropower generation,water resources utilization,navigation improvement,etc.However,dam construction may bring some negative impacts on sediment transport and channel dynamics adjustments.Due to the effects of recent water and soil conservation projects,sediment retention in the newly constructed large upstream reservoirs,and other factors,the sedimentation in the Three Gorges Reservoir(TGR)is quite different from the amount previously predicted in the demonstration stage.Consequently,based on the measured data,characteristics of sedimentation and the related channel deformation in the TGR were analyzed.The results imply that sediment transport tended to be reduced after the Three Gorges Project(TGP).Sedimentation slowed dramatically after 2013 and indicated obvious seasonal characteristics.Due to the rising water level in the TGR in the flood season,the yearly sediment export ratio(Eratio)was prone to decrease.The water level near the dam site should be reasonably regulated according to the flow discharge to improve the sediment delivery capacity and reduce sedimentation in the TGR,and to try to avoid situations where the flood retention time is close to 444 h.The depositional belt was discontinuous in the TGR and was mainly distributed in the broad reaches,and only slight erosion or deposition occurred in the gorge reaches.Sedimentation in the broad and gorge reaches accounted for 93.8% and 6.2% of the total sedimentation,respectively.The estuarine reach located in the fluctuating backwater area experienced alternate erosion-deposition,with a slight accumulative deposition in the curved reach.Sedimentation mainly occurred in the perennial backwater area.The insight gained in this study can be conducive to directly understanding of large reservoir sedimentation and mechanism of channel adjustment in the reservoir region in the main channel of large river.  相似文献   

Temporal Variations of the Frontal and Monsoon Storm Rainfall during the First Rainy Season in South China   总被引：2，自引：0，他引：2       下载免费PDF全文

YUAN Fang  WEI Ke  CHEN Wen  FONG Soi Kun  LEONG Ka Cheng 《大气和海洋科学快报》2010,3(5):243-247

The temporal variations in storm rainfall during the first rainy season (FRS) in South China (SC) are investigated in this study. The results show that the inter-annual variations in storm rainfall during the FRS in SC seem to be mainly influenced by the frequency of storm rainfall, while both frequency and intensity affect the inter-decadal variations in the total storm rainfall. Using the definitions for the beginning and ending dates of the FRS, and the onset dates of the summer monsoon in SC, the FRS is further divided into two sub-periods, i.e., the frontal and monsoon rainfall periods. The inter-annual and inter-decadal variations in storm rainfall during these two periods are investigated here. The results reveal a significant out-of-phase correlation between the frontal and monsoon storm rainfall, especially on the inter-decadal timescale, the physical mechanism for which requires further investigation.  相似文献