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841.
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   
842.
东方欧鳊(Abramis brama orientalis Berg)源于苏联咸海,我区伊犁河和额尔齐斯河均有分布,由于地理隔离的结果,两水系的东方真鳊已在形态学上出现了某些差异,为进一步探明二者间的亲缘关系,我们进行了鱼肉蛋白质含量、鱼肉氨基酸组成,LDH同工酶、血清蛋白等生化指标的比较研究,结果表明除了氨基酸组成及含量基本未发生变化外,其余三项指标均有显著不同,即说明两水系的东方欧鳊已出现种群间差异,至于是否已分化成两个不同的亚种,尚待进一步研究.  相似文献   
843.
Our main aim from this work is to see which theorems in classical probability theory are still valid in fuzzy probability theory. Following Gudder's approach [Demonestratio Mathematica 31(3), 1998, 235–254; Foundations of Physics, 30, 1663–1678] to fuzzy probability theory, the basic concepts of the theory, that is of fuzzy probability measures and fuzzy random variables (observables), are presented. We show that fuzzy random variables extend the usual ones. Moreover, we prove that for any separable metrizable space, the crisp observables coincide with random variables. Then we prove the existence of a joint observable for any collection of observables, and we prove the weak law of large numbers and the central limit theorem in the fuzzy context. We construct a new definition of almost everywhere convergence. After proving that Gudder's definition implies ours and presenting an example that indicates that the converse is not true, we prove the strong law of large numbers according to this definition.  相似文献   
844.
We considered the factors due to which the dependences between the uranium–oxygen distances R 0 and the frequencies of valence vibrations as for complex compounds of uranyl are described by two independent expressions generally represented by equations of the type R 0 = a + bas –2/3 (b > 0) with the coefficients a and b differing in the regions R 0 < 0.178 nm and R 0 > 0.178 nm. It is shown that the reason is that there is a mutual effect of the ligands in the uranyl complex responsible for different partial contributions of the uranium orbitals and of the atoms of the first coordination sphere to the chemical bonding.  相似文献   
845.
We have obtained an analytical expression for the twopulse echo signal arising in nonresonant excitation of a condensed medium with a nonuniformly broadened spectrum of doublet structure by two pulses of an electromagnetic field of different durations and of the same amplitude. It is shown that in the case where the differences between the carrying frequency of exciting pulses and the central frequencies of the spectral lines differ considerably, beatings are formed in the signal of the twopulse echo. The rate of decay of the amplitude of these beatings is found to depend only on the time of reversible and irreversible relaxation, and their circular frequency is determined by the shift of the spectral lines relative to each other. A technique for separate determination of the inhomogeneous width of the lines and time of the irreversible transverse relaxation is suggested which is based on the analysis of the twopulse echo signal beatings.  相似文献   
846.
By adding magnetic powders into matrix material, it has been proved to be a creative approach to improve tribological properties of brake materials. In this paper, a novel magnetic brake material with Nd–Fe–B and nano-Fe3O4 was developed, and the influential mechanism of these two magnetic powders and their content on the friction and wear performance was deeply discussed. Firstly, some experiments were carried out to investigate the tribological performance and influential mechanisms of four groups of brake pad samples with different magnetic powders. Furthermore, based on these results, further experiments for investigating the influence that Nd–Fe–B contents have on the tribological properties were conducted. According to the theoretical analysis about experiments, it was concluded that nano-Fe3O4 is beneficial to promote the formation of friction film and has certain lubricant effects. However, Nd–Fe–B has double effects on the formation of friction film. It will have positive effects when its content is less than a certain value. Otherwise, it will destroy the structure of friction film. Conclusively, it is believed that this study will be significantly valuable and meaningful for developing new brake materials and improving safety reliability of mechanical brakes.  相似文献   
847.
Polyfluorinated N-α-Fmoc--Boc-l-lysine represents the best-in-class among a set of polyfluorinated amino acids (PFAs) which are useful tools for 19F NMR-Based Screening. In this communication, optimized reaction conditions that allowed for the multi-gram preparation of this unnatural amino acid are reported.  相似文献   
848.
Resonance Raman spectra (RRS) of Co(II) and Co(III)5,10,15,20tetrakis(4Nmethylpyridinium)porphyrin ((CoII(TmpyP4), and CoIII(TMPyP4)) in aqueous solutions at different pH as well as in organic solvents (methanol, ethanol, DMSO, DMF) are obtained. The increased sensitivity of the oscillation frequencies 2, 4, 8, and 6 — the markers of the oxidation state of a metal — to the nature of an axial ligand has been revealed. For CoIII(TmpyP4), the shifts of the indicated frequencies in extracoordination have turned out to be twofold larger than those for CoII(TmpyP4). The spectral effects observed are related to different electron influence of the extraligands on the system of the porphyrin ring. In the case of Co(III)porphyrin, interaction of the d orbitals of the metal and the e g *orbitals of the macrocycle is more efficient since its ionic radius is smaller than for the Co(II)complex. For CoIII(TmpyP4), a linear correlation between the oscillation frequencies 2, 4, 8, and 6 and the experimental Gutmann parameters characterizing the electronacceptor properties of solvents is found.  相似文献   
849.
利用连续双波长近红外光技术测量肌肉中血红蛋白含氧量的变化情况,同时应用运动心率无线实时采集设备,设计了检测实时肌肉组织血氧含量和瞬时心率实验方案,对6名健康男性进行了100 m跑同步实测实验。实验表明,肌肉组织氧合血红蛋白浓度在100 m跑结束后继续降低,达到最低值的时刻滞后于运动结束时刻的时间为(6.65±1.10)s;心率则在运动结束后继续上升,达到最高值的时刻滞后于运动结束时刻的时间为(8.00±1.57)s。这些结果显示了双波长近红外光组织氧测试技术和运动心率无线实时采集系统能够正确检测极量强度运动时的血氧参数和心率,揭示了极量强度运动过程中肌肉中氧运输与消耗的过程及其与心率之间的动力学特征。  相似文献   
850.
Grobler  J.J. 《Positivity》1999,3(4):357-364
Let be an Abelian Archimedean lattice ordered algebra. The order bidual furnished with the Arens product is again a lattice ordered algebra. We show that the order continuous order bidual is Abelian. This solves an open problem and improves a result of Scheffold, who proved it for the case of normed lattice ordered algebras. The proof is based on the up-down-up approximation of positive elements in the order continuous order bidual by elements in the canonical image of in Components of positive elements in are characterized and the result is applied to the Arens product of -and almost -algebras.  相似文献   
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