Kr and Xe isotopic compositions of Fe-Mn crusts from the western and central Pacific Ocean and implications for their genesis

Kr and Xe nuclide abundance and isotopic ratios of the uppermost layer of Fe-Mn Crusts from the western and central Pacific Ocean have been determined. The results indicate that the Kr and Xe isotopic composi-tions, like that of He, Ne and Ar, can be classified into two types： low3He/4He type and high3He/4He type. The low3He/4He type crusts have low84Kr and132Xe abundance, while the high3He/4He type crusts have high84Kr and132Xe abundance. The82Kr/84Kr ratios of the low3He/4He type crusts are lower than that of the air, while the83Kr/84Kr and86Kr/84Kr ratios are higher than those of the air. The Kr isotopic ratios of the high-er3He/4He type crusts are quite similar to those of the air. The128Xe/132Xe,130Xe/132Xe and131Xe/132Xe ratios of the low3He/4He type sample are distinctly lower than those of the air, whereas the129Xe/132Xe,134Xe/132Xe and136Xe/132Xe ratios are higher than those of the air. The low3He/4He type samples have the diagnostic characteristics of the MORB, with excess129, 131, 132, 134, 136Xe relative to130Xe compared with the solar wind. The128Xe/132Xe,130Xe/132Xe and131Xe/132Xe ratios of the high3He/4He type samples are slightly higher than those of the air, and the129Xe/132Xe,134Xe/132Xe and136Xe/132Xe ratios are qiute similar to those of the air. The noble gases in the Fe-Mn crusts are derived from the lower mantle, and they are a mixture of lower mantle primitive component, radiogenic component and subduction recycled component. The helium isotopic ra-tios of the low mantle reservoir are predominantly controlled by primitive He （3He） and U and Th radiogenic decayed He （4He）, but the isotopic ratios of the heavier noble gases, such as Ar, Kr and Xe, are controlled to different extent by recycling of subduction components. The difference of the noble isotopic compositions of the two type crusts is the result of the difference of the noble isotopic composition of the mantle source reservoir underneath the seamounts the crusts occurred, the noble gases of the high3He/4He type crusts are     

冲绳海槽Jade热液区块状硫化物中流体包裹体的氦、氖、氩同位素组成

对冲绳海槽Jade热液区块状硫化物中流体包裹体的氦、氖和氩同位素组成进行了测定,流体包裹体的3He/4He比值为(6.2～10.1)Ra,均值为7.8Ra,与大洋中脊玄武岩一致[3He/4He≈(6～11)Ra],20Ne/22Ne比值为10.7～11.3,明显高于大气值(9.8),而40Ar/36Ar比值的变化范围在287～334之间,接近大气值(295.5),这些结果表明,块状硫化物中热液流体捕获的稀有气体是地幔和海水源组分混合的产物,且流体包裹体中的氦主要来自地幔,氖和氩主要来自海水。     

中印度洋脊Edmond热液区成矿流体属性与来源:来自流体包裹体和He-Ar同位素的证据

To understand the source and nature of the ore-forming fluids of the Edmond hydrothermal field on the Central Indian Ridge, we studied the He-Ar isotope composition and fluid inclusions of the hydrothermal precipitates.Our results show that the sulfide samples contain noble gases He, Ne, Kr, and Xe with their abundances in between those of air-saturated water(ASW) and mid-ocean ridge basalt(MORB). The ~3He/~4He ratio varies from1.3 to 8.7 R_a(n=10, average: 5.1 R_a), whereas the ~(40)Ar/~(36) Ar ratio is from 285.3 to 314.7(n=10, average: 294.8). These results suggest that the He was derived from a mixture of MORB with variable amounts of seawater, but the Ar in the ore-forming fluids trapped in the sulfides is predominantly derived from seawater. The fluid inclusions of barite have a wide range of homogenization temperatures and salinities varying from 163°C to 260°C and 2.6 wt%to 8.5 wt% Na Cl equiv., respectively. It is suggested that the ore-forming fluids were produced by phase separation, which agreed with the present-day vent fluid study.     

基于阈值光电子-光离子符合技术的分子离子光谱和解离动力学研究

对电子和离子同时采用速度聚焦电场收集的阈值光电子-光离子符合成像谱仪能够有效提高电子的收集效率和能量分辨率.利用该符合成像谱仪,开展了Xe/Ar/Ne 惰性混合气体及NO 分子的阈值光电子谱、阈值光电子-光离子符合质谱和质量选择的符合光谱等实验研究,精确测量了NO 分子的电离势,并且获得了NO⁺离子振动态分辨的X¹Σ⁺,c³Π和B¹Π态光谱.还进一步研究了NO^{+ 相似文献}   

Helium, neon and argon isotope compositions of fluid inclusions in massive sulfides from the Jade hydrothermal field, the Okinawa Trough

Helium, neon and argon isotope compositions of fluid inclusions have been measured in massive sulfide samples from the Jade hydrothermal field in the central Okinawa Trough. Fluid-inclusion 3He/4He ratios are between 6.2 and 10. l times the air value (Ra), and with a mean of 7.8Ra, which are consistent with the mid-ocean ridge basalt values [3He/^4He≈(6Ra- 11Ra)]. Values for ^20Ne/^22Ne are from 10.7 to 11.3, which are significantly higher than the atmospheric ratio (9.8). And the fluid-inclusion ^40Ar/^36Ar ratios range from 287 to 334, which are close to the atmosperic values (295.5). These results indicate that the noble gases of trapped hydrothermal fluids in massive sulfides are a mixture of mantle- and seawater-derived components, and the helium of fluid inclusions is mainly from mantle, the nelium and argon isotope compositions are mainly from seawater.     

分子核间距对非时序双电离的影响

利用半经典再散射模型研究了激光强度在一定范围内时分子核间距对非时序双电离过程的影响.分别计算了非时序双电离率、两电子的电离能、两电子的动量相关、Coulomb和激光场的复合势随分子核间距的变化关系.研究表明,分子核间距在1.0—6.0 a.u.范围内时,非时序双电离率和两电子动量和为零的双电离事件数随着分子核间距的增大而增大.当分子核间距继续增大(大于6.0 a.u.)时,非时序双电离率和两电子动量和为零的双电离事件数却减小.     

He原子掺杂铝材料的第一性原理研究

采用基于第一性原理的平面波超软赝势方法,结合广义梯度近似(GGA),计算了铝及铝晶胞间隙位置掺入He原子后体系的几何结构、电子结构、总体能量和电荷布居值.计算结果表明:随着氦在金属铝中逐渐形成,铝晶胞体系会发生晶格畸变,但总的趋势是He在铝体系的八面体位置的晶格畸变小于其在四面体位置的晶格畸变.He在铝晶胞八面体和四面体间隙的杂质形成能分别为1.3367 eV和2.4411 eV.由此可知,He在铝晶胞中最稳定位置是八面体间隙位置.同时,文中还从原子尺度层面分析了He原子在铝晶胞中的占位及其键合性质,讨论     

摆式波浪能转换装置固有圆频率理论计算研究

研究摆式波浪能转换装置固有圆频率的理论计算方法,主要探讨了船舶振动计算模型、铰接塔平台计算模型、纵摇体计算模型.通过理论计算得到不同方法下的固有圆频率,同时为了验证理论计算的正确和合理性,进行了水槽模拟试验,确定铰接塔平台计算模型是一种最佳的固有圆频率理论计算模型,为以后摆板设计提供重要依据.     

舰艇随船备件需求量的数学模型研究

针对舰艇的随船备件需求,在现有的备件数量计算模型上,分别建立了基于经济性和任务成功性的备件需求量数学计算模型,并利用实例进行了计算演示.理论分析和实例计算表明了该模型的合理性和可行性,对于新装备备件数量的确定具有指导作用.     

耗散环境下原子-库场相互作用系统中原子的偶极压缩特性

运用全量子理论并结合数值计算方法,研究了处于真空库和热库中原子系统的偶极压缩特性,讨论了原子的初态以及热库的平均光子数对原子偶极压缩特性的影响.研究表明:真空库中,初始处于基态和激发态的叠加态原子,当激发态的粒子布居概率少于基态时,原子的偶极压缩无限接近于零而永远不消失;反之,原子的偶极压缩将在有限的时间内消失;热库中,不管原子初始处于什么态,其偶极压缩都在有限的时间内消失,并且随着热库的平均光子数的增大而消失得越快.     

3CCD相机摄像系统光源的选择与计算

设计了 1种应用于 3CCD相机摄像系统中的脉冲氙灯光源。介绍了该光源的光谱特性和触发方式 ,同时计算了其包括闪光持续期和闪光频率范围等重要参数     

断层相关褶皱解释之平衡剖面技术

从实际问题出发,扼要阐述了平衡剖面技术的基本概念,并结合实例着重探讨了其应用研究.在介绍了与平衡剖面有关的基本概念的基础上,总结平衡剖面技术的研究流程和平衡剖面结果的评价标准,结合缅甸区块实际资料深入探讨其在断层相关褶皱构造模式建立和检验调整地震解释以及在恢复挤压构造发育史方面的应用情况,显示了其在缅甸区块叠瓦状断层转折褶皱的良好应用效果,并获得剖面的水平延展量,同时也认识到许多潜在的客观问题,有待进一步探索.     

钙原子二步三光子与三步三光子共振电离研究

激光共振电离光谱技术是痕量分析中的重要手段之一。本文以速率方程理论为基础 ,对钙原子的激光共振电离过程进行分析 ,通过编程对该原子的二步单色三光子和三步三色三光子非饱和激发电离过程进行模拟 ,得到了相应的电离效率与激光的能量、作用时间之间的关系曲线 ,并对这 2种电离方案进行了比较。     

海上事故有害气体的扩散研究 ——以"桑吉"轮撞船事故为例

发生海上事故后,为对周边海域船只和人员进行疏散及为应急处置提供科学依据,并实现对不同检测位置检测浓度的校正,需要对事故有毒有害气体的扩散进行计算。本文先通过经验公式计算,模拟事故船舶自然燃烧,而后采用高斯烟羽模型,通过结合事故现场的风浪等水文气象参数,构建海上事故有毒有害气体扩散模型。该模型在改进的高斯烟羽模型的基础上,通过与 ArcGIS 结合,实现事故海域区域范围内有害气体扩散定量可视化,实验结果表明,“桑吉”轮撞事故中,有害气体沿向下风向西北处扩散,以事故点为起点向西北方向划线为轴线,宽幅选取 4 km 范围,最高浓度区域是以事故点下风向 3 km处为圆心,500 m 为半径的圆形区域,浓度可以达到 4* 10-5 mg/m3,边缘处气体浓度已低至 0.5 * 10-5 mg/m3。其模型简单且可以直观体现有毒有害气体扩散范围。     

卫星海洋遥感数据的无损压缩及解压算法

在分析卫星海洋遥感单轨三级数据产品特征的基础上,针对游程编码无损压缩算法特征,提出了优化游程编码压缩算法,运用该算法实现了海洋遥感三级数据产品的无损压缩,并与流行的WinRAR压缩软件进行了比较测试,结果表明上述算法对海洋遥感数据均有较高的压缩率,优化游程编码压缩算法在空间复杂度及时间复杂度上均有明显的比较优势,可极大节约海洋遥感数据的存储与共享发布空间。     

海底管道维修管卡密封结构的性能分析及测试

密封压力是带压堵漏维修管卡的关键性能。介绍了323.9 mm(API 12英寸)维修管卡样机的总体结构及密封原理,选用接触压力准则作为管卡的密封评价准则,利用ANSYS Workbench软件建立了管卡密封结构的二维轴对称有限元模型,分析了密封结构闭环中薄弱部分在不同密封圈压缩量下的接触压力,然后试验测试了管卡样机密封圈压缩量和密封压力,并与有限元计算接触压力进行了对比。分析结果表明管卡密封结构最薄弱部分的接触压力随着周向密封圈压缩量的增大而增大,且主要是中间接触部分起到密封作用。通过试验验证了理论分析的管卡密封结构最薄弱位置,并发现相同密封圈压缩量下试验测试的密封压力与计算的接触压力近似,两者的变化趋势基本一致。有关分析思路和试验方法可以为管卡密封结构的设计提供重要参考。     

Geochemistry,origin and accumulation of natural gases in the deepwater area of the Qiongdongnan Basin,South China Sea

The Qiongdongnan Basin, South China Sea has received huge thickness (>12 km) of Tertiary-Quaternary sediments in the deepwater area to which great attention has been paid due to the recent discoveries of the SS22-1 and the SS17-2 commercial gas fields in the Pliocene-Upper Miocene submarine canyon system with water depth over 1300 m. In this study, the geochemistry, origin and accumulation models of these gases were investigated. The results reveal that the gases are predominated by hydrocarbon gases (98%–99% by volume), with the ratio of C₁/C_1-5 ranging from 0.92 to 0.94, and they are characterized by relatively heavy δ¹³C₁ (−36.8‰ to −39.4‰) and δD_CH4 values (−144‰ to −147‰), similar to the thermogenic gases discovered in the shallow water area of the basin. The C_5-7 light hydrocarbons associated with these gases are dominated by isoparaffins (35%–65%), implying an origin from higher plants. For the associated condensates, carbon isotopic compositions and high abundance of oleanane and presence of bicadinanes show close affinity with those from the YC13-1 gas field in the shallow water area. All these geochemical characteristics correlate well with those found in the shales of the Oligocene Yacheng Formation in the Qiongdongnan Basin. The Yacheng Formation in the deepwater area has TOC values in the range of 0.4–21% and contains type II_b–III gas-prone kerogens, indicating an excellent gas source rock. The kinetic modeling results show that the δ¹³C₁ values of the gas generated from the Yacheng source rock since 3 or 4 Ma are well matched with those of the reservoir gases, indicating that the gas pool is young and likely formed after 4 Ma. The geologic and geochemical data show that the mud diapirs and faults provide the main pathways for the upward migration of gases from the deep gas kitchen into the shallow, normally pressured reservoirs, and that the deep overpressure is the key driving force for the vertical and lateral migration of gas. This gas migration pattern implies that the South Low Uplift and the No.2 Fault zone near the deepwater area are also favorable for gas accumulation because they are located in the pathway of gas migration, and therefore more attention should be paid to them in the future.     

Compression limit state of HVAC submarine cables

An industry accepted standard does not currently exist for determination of compression limits in a subsea cable. This has resulted in most manufacturers specifying that subsea cables are not permitted to be axially loaded in compression.Additionally industry guidance does not exist regarding the consequences of inducing compression forces within subsea cables and the resulting effect on cable integrity. Industry recommended practice and guidance also does not have any information regarding experimental test arrangements to determine allowable compression levels within a subsea cable. This lack of modelling/testing guidance along with manufacturer recommendations of zero compressive loads within subsea cables results in overly conservative and restrictive design parameters for subsea cable installation and use.Due to the complex interaction within a subsea cable structure, such as contact interaction and friction between cable strands, theoretical modelling has been unable to provide reliable stress predictions and therefore an experimental testing regime is required if compression limits within the cable are to be appropriately determined. This paper describes combined axial and bending test arrangements that can be used as a guideline for determination of allowable compression limits for subsea cables.     

The dynamic characteristics of vortex tube-assisted hyperbaric chambers

Excessive temperature rise during compression inside hyperbaric chambers is a serious source of discomfort for their occupants. In this article a new class of vortex tube-assisted hyperbaric chambers is presented where such temperatures are reduced passively without the need for external power source. The vortex tube is utilized as means for generating the necessary cooling effect as the gases flow from their storage tanks into the chamber.Mathematical and experimental models of the new concept have been developed to study the dynamic and thermal characteristics of the vortex tube-assisted chambers under different conditions. Comparisons between such characteristics and those of unassisted chambers suggest the potential of the vortex tube assist in reducing the temperatures inside the hyperbaric chambers and accordingly the size of the installed cooling systems required for maintaining certain comfortable temperature levels.     

珊瑚的高精度热电离质谱定年和Sr/Ca温度计对古环境研究意义

珊瑚等海底沉积物中留下了过去气候变化的高分辨率记录,利用高分辨中的取样方法和热电离质谱（TIMS）铀系法对其进行测年,可以提取很短时间间隔内的环境参数,进一步证实了海洋珊瑚骨骼的Sr／Ca与海水温度间有很好的相关关系,是恢复古环境的一个有效方法。