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991.
Determination of three dimensional in situ stress from core discing based on analysis of principal tensile stress 总被引:2,自引:0,他引:2
K. Matsuki N. Kaga T. Yokoyama N. Tsuda 《International Journal of Rock Mechanics and Mining Sciences》2004,41(7):1167-1190
To determine all of the components of in situ stress from core discing, both the directions and magnitudes of the principal in situ stresses must be determined for a disc of a given thickness. In this study, we analyzed the direction and magnitude of tensile stress below an HQ core stub for 11 core lengths using stress conditions under which core discing is likely to occur. First, based on an analysis of the direction of tensile stress below the core stub, we propose a method for determining directions of in situ stress from the height distribution at the periphery of the end surface of a disc. This method can be used with a disc of any thickness. Next, based on an analysis of the magnitude of tensile stress in the central part of a core, we propose a linear criterion for core discing, which can be applied to a core of any length. This criterion was in good agreement with an empirical formula obtained previously in laboratory experiments. By combining information on the direction of in situ stress and the linear criterion for core discing, we propose a method for determining all of the components of in situ stress from core discing under the assumption that vertical stress is given by the overburden stress. Finally, these methods were applied to discs obtained from a field where hydraulic fracturing was performed to measure horizontal stresses. The results showed that the azimuths of the principal stresses estimated from core discing were consistent with those of the principal horizontal stresses determined by hydraulic fracturing and that while the magnitudes of the principal horizontal stresses estimated from core discing showed a large scatter, they were similar to those determined by hydraulic fracturing. 相似文献
992.
Computational and laboratory experiments generate masses of data that must be stored reliably, with minimal effort on each researcher's part, and must be retrievable for decades. The storage environment must also work seamlessly across scientific disciplines and capture all of a file system's features in a semantically-based catalog that provides Boolean, keyword, and tree-based data access. The authors describe a metadata-based archive for scientific data that provides flexible archive storage for very large data sets. The system uses metadata to organize and manage the data without imposing predefined metadata formats on scientists. 相似文献
993.
M. Hara Y. Hatano T. Abe K. Watanabe T. Naitoh S. Ikeno Y. Honda 《Journal of Nuclear Materials》2003,320(3):265-271
To improve the durability of hydrogen storage materials against surface poisoning by impurity gases, effectiveness of Pd-coating layer prepared by using a Barrel-Sputtering System was examined for ZrNi powder. The effectiveness of Pd-coating was evaluated by activation temperature, at which Pd/ZrNi poisoned by air could be activated to absorb hydrogen. Characterization of Pd-coated ZrNi (denoted as Pd/ZrNi) by scanning electron microscopy, electron probe microanalysis and X-ray diffraction showed that a uniform Pd-coating layer was formed with the barrel-sputtering system. It was found that the poisoned Pd/ZrNi sample could be activated even at 423 K to absorb hydrogen at room temperature. This exhibits remarkable contrast to bare ZrNi, which could be only activated appreciably above 1073 K. It is concluded that the Pd-coating by barrel sputtering is quite effective to avoid the effect of surface poisoning of powdery hydrogen storage materials. However, the activation at excessively high temperature resulted in the loss of high activity to absorb hydrogen. It was concluded that this phenomenon was associated with reactions between Pd and ZrNi to form PdZr and other byproducts. 相似文献
994.
R Albrecht TC Awes C Baktash P Beckmann F Berger R Bock G Claesson G Clewing L Dragon A Eklund RL Ferguson A Franz S Garpman R Glasow HA Gustafsson HH Gutbrod J Idh P Jacobs K Kampert BW Kolb P Kristiansson IY Lee H Loehner I Lund FE Obenshain A Oskarsson I Otterlund T Peitzmann S Persson F Plasil AM Poskanzer M Purschke H Ritter S Saini R Santo HR Schmidt T Siemiarczuk SP Sorensen E Stenlund ML Tincknell GR Young 《Canadian Metallurgical Quarterly》1991,44(6):2736-2752
995.
Averin S.V. Kohl A. Muller R. Mesquida Kusters A. Wisser J. Heime K. 《Electronics letters》1992,28(11):992-995
The p/sup +/-cap layer was used to fabricate a metal-semiconductor-metal (MSM) interdigitated photodetector on Ga/sub 0.47/In/sub 0.53/As. The measured barrier height was Phi /sub Bn=/0.52 V, the ideality factor n=1.1 and average dark current density 2 mA/cm/sup 2/. A rise time of 45 ps at lambda =1.3 mu m under 2 V bias was measured for an MSM photodiode with 3 mu m finger width and finger gaps and an active area of 100*100 mu m/sup 2/.<> 相似文献
996.
The parasitic bipolar transistor inherent in the power vertical Double Diffused MOSFET (DMOSFET) structure can have a significant impact on its performance and reliability. Selectively formed TiSi2 films on source contacts were used to reduce the contact resistance to n + source diffusion. These devices exhibit “kinks” in the output I-V characteristics. High contact resistance of TiSi2 to moderately doped p-body diffusion causes high output conductance. Detailed two-dimensional numerical simulations are used to investigate the effect of the parasitic bipolar transistor on the static characteristics of scaled silicided DMOSFET's. The high contact resistance of TiSi2-p-body interface leads to a floating potential and causes significant reduction in the MOS gate threshold voltage and results in a premature bipolar turn-on. It is shown that the parasitic bipolar turn-on places an important constraint on the scalability of the device into the submicron regime. A novel self-aligned DMOSFET structure with a shallow diffused p+ region is shown to eliminate this effect. Numerical simulations are shown to be in excellent agreement with the measured data at various temperatures 相似文献
997.
Bykov Yu. A. Karpukhin S. D. Panfilov Yu. V. Boichenko M. K. Cheptsov V. O. Osipov A. V. 《Metal Science and Heat Treatment》2003,45(9-10):396-399
A method for evaluating the hardness of coatings with nanosize thickness is suggested. The method includes the determination of the hardness of the “coating-substrate” composition by indenting the coating and subsequent computation of the hardness with the use of the additivity rule. This requires determination of the thickness of the coating, of the hardness of the substrate, and of the indentation depth. 相似文献
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