On the Distance Function Between Two Keplerian Elliptic Orbits   总被引：1，自引：0，他引：1  

Konstantin V. Kholshevnikov  Nikolay N. Vassiliev 《Celestial Mechanics and Dynamical Astronomy》1999,75(2):75-83

The problem of finding critical points of the distance function between two Keplerian elliptic orbits is reduced to the determination of all real roots of a trigonometric polynomial of degree 8. The coefficients of the polynomial are rational functions of orbital parameters. Using computer algebra methods we show that a polynomial of a smaller degree with such properties does not exist. This fact shows that our result cannot be improved and it allows us to construct an optimal algorithm to find the minimal distance between two Keplerian orbits. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Characterization of the Karababa-C reservoir in the South Karaku oilfield, southeast Turkey     

M. Ulu  N. Karahano lu 《Marine and Petroleum Geology》1998,15(8):319

The South Karaku oil field is located in southeast Turkey, and produces, from the Late Cretaceous Mardin Group, carbonate reservoirs consisting of the Karababa, Derdere, Sabunsuyu and Areban Formations. The Karababa Formation is divided into three members, of which the productive Karababa-C member, discussed here, is composed of shallow marine bioclastic mudstone to wackestone. It is affected by early to late diagenetic processes that caused modification of the original pore system by cementation, dissolution and fracturing. Two petrophysical-petrologic facies can be discriminated by principal component analysis, and linear, multiple and stepwise multiple regression analysis of petrophysical data. These correspond to vuggy-moldic porosity and microporosity dominated reservoirs.  相似文献   

Mössbauer effect study of anapaite, Ca2Fe2+(PO4)2 · 4H2O, and of its oxidation products     

S. G. Eeckhout  E. De Grave  R. Vochten  N. M. Blaton 《Physics and Chemistry of Minerals》1999,26(6):506-512

Mössbauer spectra (MS) of anapaite (Ca₂ Fe²⁺(PO₄)₂?·?4H₂O) and of a sample after being immersed in a 4% H₂O₂ solution at room temperature (RT) over 12 days (hereafter an4ox) were collected at temperatures in the range 4.2 to 420?K and 11 to 300?K respectively. All MS consist of symmetrical doublets, hence magnetic ordering was not observed. The temperature dependencies of the Fe²⁺ centre shifts of anapaite and an4ox were analysed with the Debye model for the lattice vibrations. The characteristic Mössbauer temperatures were found as 370?K?±?25?K and 340?K?±?25?K, and the intrinsic isomer shifts as 1.427?±?0.005?mm/s and 1.418?±?0.005?mm/s respectively. From the external-field (60?kOe) MS recorded at 4.2 and 189?K for the non-treated sample, the principal component V _zz of the electric field gradient (EFG) is determined to be positive and the asymmetry parameter η?≈?0.2 and 0.4 respectively. The temperature variations of the quadrupole splittings, ΔE _Q(T), cannot be interpreted on the basis of the thermal population of the ⁵ D electronic levels resulting from the tetragonal compression of the O₆ co-ordination. The low-temperature linear behaviour of ΔE _Q(T) is attributed to a strong orbit-lattice coupling. A field of 60 kOe applied to anapaite at 4.2?K produces magnetic hyperfine splitting with effective hyperfine fields of ?136, ?254 and ?171?kOe along the principal axes Ox, Oy and Oz of the EFG tensor respectively. Additional oxidation treatments in solutions with various H₂O₂ concentrations up to 20% and subsequent Mössbauer experiments at room temperature, have revealed that the anapaite structure is not sensitive to oxidation since eventually only a small amount of Fe²⁺ (～6.5%) is converted into Fe³⁺.  相似文献   

57Fe Mössbauer spectroscopy of tektites     

S. Rossano  E. Balan  G. Morin  J.-P. Bauer  G. Calas  C. Brouder 《Physics and Chemistry of Minerals》1999,26(6):530-538

Tektite glasses are investigated using ⁵⁷Fe Mössbauer spectroscopy. Room temperature spectra analysis is performed using two complementary analytical methods based on two-dimensional distributions of both isomer shift and quadrupole splitting. No a priori correlation between the two hyperfine parameters is considered. The first method, based on a shape independent distribution, provides the justification for the Gaussian distribution shape used in the second method. No ferric iron contribution is evidenced by Mössbauer spectra analysis in these samples, although several criteria are used. Ferrous iron sites are shown to be continuously distributed between four- and five-fold co-ordinated sites.  相似文献   

伽玛能谱参数与金矿找矿   总被引：1，自引：0，他引：1  

曾庆栋  沈远超  张启锐  李慎之  刘铁兵  杨金中 《华东地质学院学报》1999,22(1):34-39

γ能谱测量方法是一种简便、有效、快速的间接找金的方法,不同类型的金矿其伽玛能谱特征并不相同。与深成脉岩活动有关的脉状金矿,具有明显的伽玛能谱Ｋ／Ｕ参数异常;与中浅成中酸性侵入发杂岩体有关的金矿,具有Ｋ／Ｕ,Ｋ／Ｔｈ参数正异常;而与浅成－超玫成偏碱性杂岩体有关的隐爆角砾岩型金矿,则具有一致的Ｕ,Ｔｈ,Ｋ及Ｆ参数正异常。本介绍了在山东东部乳山地区及临沂西部地区,利用没的伽玛能谱参数进行不同类型的金矿  相似文献   

Aliphatic biomarker signatures of early Oligocene-early Miocene source rocks in the central Qiongdongnan Basin: Source analyses of organic matter     

Min Xu  Dujie Hou  Xiong Cheng  Jun Gan  Xinde Xu  Gang Liang  Wenjing Ding 《海洋学报(英文版)》2023,42(3):1-18

The geochemical signatures of fifty-four rock samples and three supplementary drill stem test(DST) oils from the Yacheng-Sanya formations in the central Qiongdongnan Basin(CQB) were analysed. Reconstruction of the early Oligocene-early Miocene(36–16 Ma) palaeovegetation and source analyses of organic matter(OM) were conducted using aliphatic biomarkers in ancient sediments and DST oils. Both the interpreted aquatic and terrigenous OM contributed to the CQB source rocks(SRs) but had varying relat...  相似文献   

中国湖泊综合分类原则、级别划分及分类程序之初探   总被引：4，自引：1，他引：3  

窦鸿身  王苏民  姜加虎  汪宪栕 《湖泊科学》1996,8(2):173-178

在略述了国内外湖泊分类研究现状的基础上,探讨了开展我国湖泊综合分类的原则、级别划分以及综合分类所应该遵循的程序。主导因素与综合因素相结合,建立分类的主导标志,是湖泊综合分类系统中高层次分类的关键;区域相似性（相对一致性）与差异性的对比分析是低层次分类的重要环节。在此基础上,还应充分考虑到人类经济活动的方式与强度对湖泊诸自然因素的影响,以便使湖泊综合分类工作既具有理论上的意义,同时又具有实用价值。级  相似文献   

准噶尔盆地玛湖凹陷西斜坡三叠系百口泉组扇三角洲优质储集层预测          下载免费PDF全文

桑林翔  刘军  王贵文  王苏天  李全  张云龙 《古地理学报》2020,22(6):1053-1064

针对准噶尔盆地玛湖凹陷西斜坡风南地区三叠系百口泉组扇三角洲砂岩物性空间变化大、优质储集层(孔隙度大于7.4%,渗透率大于0.05×10^-3μm²)预测难的问题,在沉积岩石学、地震沉积学以及地震反演和解释理论指导下,综合利用测井、岩心和三维地震等资料开展了高精度层序地层划分、沉积微相描述和优质储集层地震反演研究。建立了风南井区四级层序地层格架,明确了扇三角洲多期水进水退的充填过程,指出SSQ3和SSQ5是优质储集层的发育层系;识别出扇三角洲平原分流河道、河道间和扇三角洲前缘水下分流水道、河口坝、席状砂等沉积微相,指出扇三角洲平原是优质储集层发育相带;通过应用高分辨层序地层纵向边界和沉积相横向边界约束,进行分层相控叠后地震波阻抗反演,提升储集层预测精度,在SSQ3和SSQ5预测5个优质储集层发育区,提出3口井的井位建议,钻探均获工业油流。  相似文献   

Stable carbon isotope signatures of cellulose in macrophytes collected from three eutrophic lakes in China     

《Limnologica》2020

Aquatic plants are essential for maintaining the diversity and stability of a lake ecosystem. Stable carbon isotopes (δ¹³C) of macrophytes have been widely used as a powerful tool to study ecological processes and paleoenvironmental evolution in lakes. Varying results are obtained when using the δ¹³C of macrophytes to study the changes in the lake environment at different spatio-temporal scales. Thus, sample preparation and subsequent laboratory analyses are crucial for studying environmental changes using the isotopic signal retained in the macrophytes, and are essential for the interpretation of isotope-environment relationships. This study analyzed the δ¹³C of different tissue components of macrophytes in three lakes of the lower Yangtze River basin, and a correlation analysis was performed on aquatic environments influencing the δ¹³C values in the different tissue components of macrophytes. The test results showed the difference between the δ¹³C values of the whole sample and cellulose. Relative analyses indicated that the major factors contributing to the δ¹³C variability in macrophytes were pH and the concentration of dissolved inorganic carbon (DIC). The δ¹³C of α-cellulose (δ¹³C_AC) is more sensitive to environmental variables than that of the whole sample (δ¹³C_W) and holocellulose (δ¹³C_HC). The results of this study imply that extraction of α-cellulose is a prerequisite for research on the changes in lake environment using δ¹³C of macrophytes. This study aims to provide theoretical and data basis for further research on the environmental and ecological change using stable carbon isotopes of aquatic plants.  相似文献   

基于有限杆单元法的陡坡基桩非线性分析     

赵明华  陈耀浩  杨超炜  肖尧 《岩土力学》2018,39(8):3020-3028

根据陡坡段桥梁基桩承载特性,提出了一种可考虑桩土非线性作用的基桩内力与位移分析有限杆单元方法。首先,基于单元划分结果,结合桩侧摩阻力和坡体侧向推力的分布规律,得到了相应的等效结点荷载向量表示方法;其次,在线弹性地基反力法的基础上,引入p-y曲线开展了桩周土抗力非线性分析,并结合桩身P-?效应（P为桩顶轴向荷载,?为桩顶水平位移）计算方法给出了单元刚度矩阵修正方法,进而提出了适用于基桩内力位移非线性分析的有限杆单元法并编制了MATLAB计算程序;最后,结合某工程实例,将计算结果与工程实测值及已有理论值进行对比。结果表明：考虑桩土非线性作用的计算方法是合理的;当桩身具有自由段时,P-?效应对基桩内力位移的影响较大,在实际工程设计中不可忽视。  相似文献