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排序方式: 共有197条查询结果,搜索用时 0 毫秒
31.
C.-D. Zhao G. Haase M. Heck M. Tufail P. Vater H. A. Khan 《Isotopes in environmental and health studies》2013,49(6):296-299
222Rn dissolved in drilling fluids of the KTB (Kontinentales Tiefbohrprogramm der Bundesrepublik Deutschland) pilot hole has been determined using solid state nuclear track detector (SSNTD) technique:The α-sensitive SSNTD CR-39 was used to measure the a-activity of 222Rn. Well-defined conditions for Rn-measurements could be established by employing a mica nuclear track microfilter to separate the detector containing air volume from the volume containing the water. This technique has been applied to determine quantitatively the 222 Rn-concentration as a function of depth of the borehole down to 4000 m. 相似文献
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石油钻井和完井过程中,经常出现泥浆、水泥浆和完井液在偏心环空中的流动。Robertson-Stif流体在描述这些流体的流变性时有很高的精度。文中根据Robertson-Stif流体的流变方程和偏心环空环隙间距的几何关系,利用相似原理,求解了该流体在偏心环形空间中作层流轴向流动时适于工程应用的二元速度分布,以及平均流速、流量和压降的表达式。研究表明:液体在偏心环形空间流动时与在同心环空中流动的最大差异,在于流经偏心环空不同间隙处流速的较大差异。文中还把Robertson-Stif流体的计算结果与采用宾汉模式和幂律模式的计算结果进行了对比。 相似文献
33.
A. Kuhn I. J. Blewett D. P. Hand P. French M. Richmond J. D. C. Jones 《Optics and Lasers in Engineering》2000,34(4-6):273-288
This paper investigates the extension of optical fibre beam delivery to high-brightness applications, in particular laser percussion drilling, where both a good beam quality and high peak power are required. Beam quality preservation through a number of optical fibres is studied both experimentally and by using a ray propagation model. It is determined that in order to achieve the beam quality required for percussion drilling (M2<30) the largest fibre which can be used is 400 μm diameter. The laser-induced damage threshold is measured for a number of 400 μm fibres, and a CO2 laser-annealing technique is shown to increase the damage threshold by a factor of 10, allowing 28 J, 1 ms pulses to be transmitted. 相似文献
34.
H. Kleinke 《无机化学与普通化学杂志》1998,624(11):1771-1776
ScCoSb: the Most Valence-Electron-Poor Ternary Transition Metal Antimonide MM'Sb with M–M Bonding The antimonide ScCo1–xSb was prepared by arc-melting the elements. ScCoSb crystallizes in the TiNiSi structure type, occurring as a drilling. The lattice parameters are a = 680.62(6) pm, b = 425.65(5) pm, c = 737.77(8) pm, V = 213.74 106 pm3 (space group Pnma, Z = 4). Besides strong Sc–Sb-, Co–Sb-, and Sc–Co bonding, Sc–Sc bonds stabilize the structure to a small extent. The results of Extended Hückel calculations point to metallic properties of ScCoSb, which are confirmed by measurements of the electrical resistivity as a function of temperature. 相似文献
35.
In this study, initially, we tried to obtain the mechanoradicals of PMMA (poly(methyl methacrylate)). For this purpose, we designed a simple drilling apparatus. Using this apparatus, we prepared some PMMA samples at 77 K in vacuum. Later, by using an ESR (electron spin resonance spectrometer), we observed ESR signals for these samples at 77 K. This means that mechanoradicals have been successfully produced by mechanical fracture in PMMA using our drilling apparatus. Secondly, we tried to identify the radicals from these spectra through using theoretical analyses and, some computer simulations have been done by suggesting two different theoretical models for these ESR signals. Finally, by using experimental and theoretical data, we showed that our simple apparatus could be used to obtain mechanoradicals from polymers. Results were seen to be in very good agreement with the literature. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35 : 2195–2200, 1997 相似文献
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含油气的岩层被钻开以后,其中的油气一部分保留在岩样中,另一部分则进入钻井液,岩样中的油、气及钻井液中的气都有相应的录井方法来检测,唯独钻井液中的油一直是录井检测的空白. 随着油气勘探程度的加深及钻井工艺技术的发展,岩屑含油级别低甚至无显示、气测异常幅度低甚至无异常的油井是越来越多,导致油气层的发现与评价变得十分困难. 因此,急需对钻井液中的含油量进行随钻检测. 通过对不同油质、 不同含油量的钻井液进行磁共振试验,结果表明,可以通过核磁共振一维谱(T2谱)实现轻~中质油的含油量分析,通过二维谱(T2-D谱)以实现对重质油的含油量分析. 该项研究对于完善录井技术系列、提高油层发现率和评价准确率具有十分重要的意义. 相似文献
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The same shot-peening treatment was applied to five steels with different mechanical properties. The induced residual stress profiles were analyzed using X-ray diffraction and incremental hole drilling (IHD). The results of both techniques showed that IHD can still be successfully used for measuring shot-peening residual stresses, even if these exceed the yield strength of the bulk material. Expected errors due to the plasticity effect are reduced by the strain hardening of the surface. For an assessment of the reliability of IHD data, strain-hardening variation was quantified by microhardness measurements to estimate the yield strength of the plastified layer. All the main calculation methods for IHD were applied. The results were compared and discussed with respect to the characteristics of each method. 相似文献