The Simulation of Orbit Decay of Double Neutron Star System PSR J1906+0746 by the Gravitational Wave Radiation     

Liu  Peng  Zhang  Cheng-Min  Li  Di  Yang  Yi-Yan  Zhang  Jie  Zhang  Jian-Wei 《Astronomy Reports》2019,63(12):1090-1094

With the discovery of the double neutron star (DNS) merger event GW170817 by LIGO, DNS systems have become one of the important candidates for gravitational wave (GW) observation. There are 19 DNS systems that have been discovered, and PSR J1906+0746 is the youngest DNS system with the age of about 0.1 Myrs. We simulate its orbital decay over its entire life by the GW radiation from the initial stage to the coalescence. For the DNS PSR J1906+0746, we obtain its initial orbital period of 3.99 hrs (3.98 hrs at present) with the nearly circular orbit, and the merger age of 3.18 × 10⁸ yr. At the last minute of coalescence, corresponding to the orbital radius change from 335 to 30 km, we present the GW frequency to be 30 and 1122 Hz, respectively. As a comparison, with the GW frequency from 45 to 450 Hz, the orbital radii of the source GW170817 correspond to 163 and 57 km, respectively.

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Dating magmatic and hydrothermal processes using andradite-rich garnet U–Pb geochronometry     

Xiao-Dong?DengEmail author  Jian-Wei?LiEmail author  Tao?Luo  Hong-Qiang?Wang 《Contributions to Mineralogy and Petrology》2017,172(9):71

Andradite-rich garnet is a common U-bearing mineral in a variety of alkalic igneous rocks and skarn deposits, but has been largely neglected as a U–Pb chronometer. In situ laser ablation-inductively coupled plasma mass spectrometry U–Pb dates of andradite-rich garnet from a syenite pluton and two iron skarn deposits in the North China craton demonstrate the suitability and reliability of the mineral in accurately dating magmatic and hydrothermal processes. Two hydrothermal garnets from the iron skarn deposits have homogenous cores and zoned rims (Ad₈₆Gr₁₁ to Ad₉₈Gr₁) with 22–118 ppm U, whereas one magmatic garnet from the syenite is texturally and compositionally homogenous (Ad₇₀Gr₂₂ to Ad₇₇Gr₁₄) and has 0.1–20 ppm U. All three garnets have flat time-resolved signals obtained from depth profile analyses for U, indicating structurally bound U. Uranium is correlated with REE in both magmatic and hydrothermal garnets, indicating that the incorporation of U into the garnet is largely controlled by substitution mechanisms. Two hydrothermal garnets yielded U–Pb dates of 129 ± 2 (2σ; MSWD = 0.7) and 130 ± 1 Ma (2σ; MSWD = 0.5), indistinguishable from zircon U–Pb dates of 131 ± 1 and 129 ± 1 Ma for their respective ore-related intrusions. The magmatic garnet has a U–Pb age of 389 ± 3 Ma (2σ; MSWD = 0.6), consistent with a U–Pb zircon date of 388 ± 2 Ma for the syenite. The consistency between the garnet and zircon U–Pb dates confirms the reliability and accuracy of garnet U–Pb dating. Given the occurrence of andradite-rich garnet in alkaline and ultramafic magmatic rocks and hydrothermal ore deposits, our results highlight the potential utilization of garnet as a powerful U–Pb geochronometer for dating magmatism and skarn-related mineralization.  相似文献   

Hydrothermal titanite from the Chengchao iron skarn deposit: temporal constraints on iron mineralization,and its potential as a reference material for titanite U–Pb dating     

Hu  Hao  Li  Jian-Wei  McFarlane  Christopher R. M. 《Mineralogy and Petrology》2017,111(4):593-608

Mineralogy and Petrology - Uranium–lead isotopes and trace elements of titanite from the Chengchao iron skarn deposit (Daye district, Eastern China), located along the contact zones between...  相似文献   

Wavefield simulation in porous media saturated with two immiscible fluids     

Ying-Chun Tian  Jian-Wei Ma  Hui-Zhu Yang 《应用地球物理》2010,7(1):57-65

Wavefields in porous media saturated by two immiscible fluids are simulated in this paper. Based on the sealed system theory, the medium model considers both the relative motion between the fluids and the solid skeleton and the relaxation mechanisms of porosity and saturation (capillary pressure). So it accurately simulates the numerical attenuation property of the wavefields and is much closer to actual earth media in exploration than the equivalent liquid model and the unsaturated porous medium model on the basis of open system theory. The velocity and attenuation for different wave modes in this medium have been discussed in previous literature but studies of the complete wave-field have not been reported. In our work, wave equations with the relaxation mechanisms of capillary pressure and the porosity are derived. Furthermore, the wavefield and its characteristics are studied using the numerical finite element method. The results show that the slow P3-wave in the non-wetting phase can be observed clearly in the seismic band. The relaxation of capillary pressure and the porosity greatly affect the displacement of the non-wetting phase. More specifically, the displacement decreases with increasing relaxation coefficient.  相似文献   

碳酸盐岩储集层成岩作用中“孔隙尺寸控制沉淀”研究进展、地质意义及鄂尔多斯盆地实例^*     

熊鹰  谭秀成  伍坤宇  王小芳 《古地理学报》2020,22(4):744-760

基于碳酸盐岩储集层成岩作用中受孔隙尺寸控制的矿物沉淀和胶结非均质特征的发现与思考,结合当今国内外有关多孔介质中流体—岩石相互作用及化学流体动力学研究进展的调研,对相关研究进展及其地质意义进行了简单的梳理和归纳。(1)地质环境中“孔隙尺寸控制沉淀”现象广泛存在,表现为储集层孔隙的胶结非均质性及其最终形成的“大孔充填而小孔保存”特征。现今研究主要从不同尺度孔隙结构观察、流体—孔隙介质相互作用的数值模拟、矿物沉淀实验3个方面开展。(2)受孔隙尺寸控制的非均质沉淀特征可以利用与表面化学相关的动力学模型进行解释,即微孔隙中更大的界面张力和矿物晶体曲率导致矿物的有效溶解度更高,因而更容易保持过饱和状态而不发生沉淀。(3)“孔隙尺寸控制沉淀”现象可使油气储集层发生微孔的选择性保存,在不同尺度孔隙共生的情况下,较大孔隙更倾向于被胶结充填而小孔则更易于被保存,不同的胶结模式对岩石整体渗透率的影响略有不同;该现象在地热储集层开发和二氧化碳地质封存研究中也值得重视。最后,结合鄂尔多斯盆地马家沟组碳酸盐岩储集层的非均质胶结特征和孔隙分布,分析总结成岩流体性质、来源及胶结模式差异对孔隙结构演化和优质储集层分布的影响。“孔隙尺寸控制沉淀”现象的发现和重视对于理解流体—岩石复杂作用过程具有重要理论意义,也为储集层成岩作用和孔隙保存研究提供了新的视点和思考角度。  相似文献   

大坡度地质露头高分辨率无人机影像采集方法与建模实践^*     

盛辉  段政明  刘善伟  曾喆  冯建伟 《古地理学报》2020,22(4):799-806

野外地质露头的观察、研究能够最直接、最有效地获取地下地层信息,为地质科学研究提供最直观、最真实的一手地质资料。然而传统的露头研究,尤其针对大坡度、人员无法到达区域的露头研究,主要依赖坡底部考察、测量和拍照等方式记录露头信息,难以精细、准确地表征整个地质体。消费级无人机具有机动性好、适应性强和成本低等优势,且能够近距离、多视角、变高度地获取露头影像。本研究对无控制点情况下的大坡度地质露头影像采集方法与模型构建精度进行探讨,利用消费级无人机垂向航线采集影像,然后构建模型。结果证明倾斜摄影测量技术结合消费级无人机能够有效地构建具有毫米分辨率精度的大坡度地质露头模型。构建的模型具有分辨率高、分辨率均一、量测精度可达毫米等特点,可有效降低野外考察的工作难度,降低人员安全风险,真实准确地复现野外大坡度露头情况,为大坡度露头剖面解译、分析和量测提供真实可靠的数据基础。  相似文献   

Mineralogy and 40Ar/39Ar geochronology of supergene Mn-oxides in the Dongxiangqiao deposit,Hunan Province,South China     

Deng  Xiao-Dong  Li  Jian-Wei 《Mineralogy and Petrology》2017,111(2):253-265

Mineralogy and Petrology - The Dongxiangqiao Mn deposit in Hunan Province is one of numerous supergene Mn-oxide deposits in central South China. This deposit is derived from chemical weathering of...  相似文献   

潮汕海岸带河-海交互区沉积环境及小型底栖动物群落结构研究          下载免费PDF全文

俞越  王嫣贝  范魏丰  董建玮  王红兵  袁振威  耿乐  杜永芬  李玉凤 《海洋与湖沼》2024,55(1):155-170

河口三角洲是人类活动最为剧烈的区域, 陆海作用复杂, 生态环境脆弱。2021年6月以潮汕韩江三角洲河口群为研究区, 开展了河-海交互区沉积环境和小型底栖动物群落综合研究。结果表明, 研究区沉积物以黏土质粉砂为主, 中值粒径为6.66~1 301.34 μm; 盐度为15.91~35.11, 具有典型的河-海交互区特征; 有机碳(TOC)、叶绿素a (chl a)、脱镁叶绿酸含量(Phaeo)均呈现由陆向海减少趋势。重金属Cu和Zn、Phaeo、透明度和砂含量是造成沉积环境差异的主要因素。共鉴定出13个小型底栖动物主要类群, 其中自由生活海洋线虫在丰度和生物量上均为最优势类群(90%和38%), 桡足类和多毛类居次。小型底栖动物的平均丰度和生物量(干重)分别为(295±195) inds./10 cm²和(277.8±202.8) μg/10 cm²,整体上从陆向海呈增加趋势, 在不同河口断面间差异显著。盐度和河口也是控制小型底栖动物群落空间分布的主要因素, 真盐区(盐度>30)的群落相似性较高。小型底栖动物丰度、生物量和物种数与Phaeo和重金属(Cu、Zn、Pb、Cd)呈负相关关系; 解释小型底栖动物群落结构差异的最佳环境组合是盐度和重金属Cd含量。基于重金属、有机污染指数及海洋线虫与桡足类比值三种环境评价方法, 其结果均显示污染较严重的区域位于河口入海口门处。研究结果可为海岸带资源保护、生态监测以及基于生态系统实施综合管理提供基础数据支撑。  相似文献   

钙原子束光学Ramsey实验的初步工作     

黄凯凯  张建伟  陈景标  王凤芝  杨东海 《时间频率学报》2006,29(1):58-65

报告了实现钙原子光频标的前期工作—钙原子束的光学Ramsey谱线研究的初步工作,介绍了实验的系统方案、真空和激光器部分的设计以及部分已完成的工作。在得到光学Ramsey线形后,如果把激光器锁定在谱线上,就可以得到一个高精度的光学频率标准。  相似文献   

Gold distribution in As-deficient pyrite and telluride mineralogy of the Yangzhaiyu gold deposit,Xiaoqinling district,southern North China craton   总被引：3，自引：0，他引：3  

Shi-Jian Bi  Jian-Wei Li  Mei-Fu Zhou  Zhan-Ke Li 《Mineralium Deposita》2011,46(8):925-941

The Mesozoic Yangzhaiyu lode gold deposit is situated in the southern edge of the North China craton. Gold mineralization is hosted in Archean amphibolite facies metamorphic rocks, and consists mainly of auriferous quartz veins. Pyrite is the predominant sulfide mineral, with minor amounts of chalcopyrite, sphalerite, and galena. Based on morphology and paragenesis, there are three generations of pyrite, termed as first generation (G1), second generation (G2), and third generation (G3). They have distinct contents, occurrences, and distribution patterns of gold. The coarse-grained, euhedral G1 pyrite contains negligible to low levels of gold, whereas both invisible and visible gold are present in the fine- to medium-grained G2 pyrite that is characterized by abundance of microfractures and porosities, forming a foam-like texture. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) depth profiles indicate that invisible gold occurs either as solid solution or as nanoparticles of gold-bearing tellurides in the G2 pyrite. Visible gold is widespread and present as irregular grains and stringers of native gold mostly along grain boundaries or filling microfractures of pyrite, likely resulting from remobilization of invisible gold once locked in the G2 pyrite. The G3 pyrite, invariably intergrown with chalcopyrite, sphalerite, and galena, contains the highest levels of invisible gold. There is a positive correlation between Au, Ag, and Te, indicating that gold occurs as submicroscopic Au-bearing telluride inclusions in the host minerals. Whenever gold, either invisible or visible, is present, As is always below or only marginally higher than the detection limit of LA-ICP-MS. This indicates that As played an insignificant role in gold mineralization. Tellurides are widespread in the auriferous quartz veins, consisting mainly of petzite, calaverite, hessite, altaite, and tellurobismuthite. Native gold commonly occurs as intergrowths with tellurides. Textural evidence indicates a precipitation sequence, in a temporal order, of calcaverite, petzite, altaite, tellurobismuthite, and hessite. Little amount of sulfide phases has been found in association with the tellurides, indicating that tellurides were deposited under low S fugacity (fS ₂ ) and/or high Te fugacity (fTe ₂ ) conditions. The textural relationships, when combined with fluid inclusion microthermometric data of auriferous quartz veins and tellurides thermodynamic data, permit estimation for logfTe ₂ during telluride formation, which are −6.8 to −10.8 at 300°C and −9.6 to −17.6 at 250°C. Available geochronological and geochemical data suggest that Te was most likely derived from the late Mesozoic magmatic rocks widespread in the Xiaoqinling district and other parts of the southern North China craton, which were emplaced broadly contemporaneous with gold mineralization at Yangzhaiyu. This study highlights the role of Te and tellurides as important gold scavengers in As-deficient ore fluids.  相似文献