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71.
NAM-SU HUH JONG-MIN KIM YOON-SUK CHANG YOUNG-JIN KIM SEONG-SIK HWANG JOUNG-SOO KIM 《Fatigue & Fracture of Engineering Materials & Structures》2007,30(2):131-142
The present work provides an elastic‐plastic fracture mechanics (EPFM) assessment scheme for a steam generator tube with a through‐wall crack under internal pressure. Noting that the geometry and material are rather uniform for steam generator tubes, and furthermore the only loading to be considered is internal pressure, an engineering EPFM analysis method is proposed to assess through‐wall cracks in steam generator tubes. Important outcomes of the present work are closed‐form approximations for J and crack opening displacement (COD). Sufficient confidence in the proposed J and COD estimates is gained from good agreements with the finite element results over a wide range of the crack length and pressure magnitude. Another important element of the EPFM assessment is to determine relevant J‐resistance curve for steam generator tubes. To improve the accuracy of predicting tube failure, the present paper also proposes a new method to determine fracture toughness using an actual tubular specimen instead of using a standard specimen, from which J‐resistance curves of steam generator tubes are obtained. Using the proposed J and toughness estimates, maximum pressures of steam generator tubes with through‐wall crack are estimated based on EPFM analysis, which is compared with experimental results and predicted ones based on limit load approach. 相似文献
72.
ZHANG Zai-xuan WANG Jian-feng LIU Hong-lin XU Hai-fen DAI Bi-zhi LI Chen-xia LI Lan-xiao GENG Dan INSOO S. KIM 《光电子快报》2007,3(6)
A 31 km long range distributed optical fiber Raman photon temperature sensor (DOFRPTS) system have been developed based on temperature effect of the amplified spontaneous Raman scattering in fiber, and using fiber laser as a pumped source. The results show that temperature measuring uncertainty is ±2 ℃, temperature resolution is 0.1 ℃, measurement time is 432 s, spatial resolution is less than 4 m. 相似文献
73.
The electrical conductivity of pure aluminum oxynitride spinel was measured at 1300° to 1500°C under flowing nitrogen gas. The re sults for two nonstoichiometric spinel compositions can be fitted by exponential expressions with an activation energy of 116± I Wlmol. The mobilities calculated from aluminum vacancy concentrations and conductivities, 8.07x cm'/V-s, are reasonable for ionic conduction. The complex impedance plot suggests electrode double-layer effects being damped out at higher frequencies in the range 10'to lo4 Hz. 相似文献
74.
EFFECTS OF OIL DROPLET AND AGAR CONCENTRATION ON GEL STRENGTH AND MICROSTRUCTURE OF O/W EMULSION GEL 总被引:1,自引:0,他引:1
KYUNG-HEE KIM SHOICHI GOHTANI RYUICHI MATSUNO YOSHIMASA YAMANO 《Journal of texture studies》1999,30(3):319-335
The effects of oil droplet size and agar concentration on gel strength and microstructure of emulsion gels were investigated by compression test and cryoscanning electron microscope (Cryo-SEM). At all agar concentrations, the compressive stress values of emulsion gels were lower than those of the oil-free gels. Compressive stress and energy were significantly affected by oil droplet size and agar concentration, but compressive strain was not. SEM observation revealed that the overall volume of void spaces decreased and strand compactness increased with increasing agar concentration. Gels containing oil droplets had some void spaces between the gel network and the oil droplets. The strands of emulsion gels did not cover the oil globules completely, a phenomenon which was also observed for the gel with high agar concentration. 相似文献
75.
Min Ku LEE Jung Gu LEE Jong Keuk LEE Sung Mo HONG Sang Hoon LEE Jin Ju PARK Jae Woo KIM Chang Kyu RHEE 《中国有色金属学会会刊》2011,(Z1):7-11
The microstructures of the brazed joints for commercially pure Ti and stainless steel were investigated by the applications of various filler alloys including Ag-, Ti-, Zr- and Ni-based alloys. Generally, the dissimilar joints between Ti and stainless steel were dominated by the Ti-based intermetallic compounds (IMCs), e.g. (Ti, Zr)2(Fe, Ni), TiFe, TiCu, and Ti2(Fe, Ni), due to a significant dissolution of Ti from the base metal. The (Fe-Cr) σ phase was also observed near the stainless steel due to a segregation of Cr into the interface region. This research demonstrates empirically that the brittleness of the Ti and stainless steel joint can not be avoided only by applying single braze alloy or single insert metal, and thus an introduction of additional suitable interlayer between the filler alloy and the base metal is necessary to prevent the brittleness of the joint. 相似文献
76.
In a recent study by Gurnani (1983), ‘Economic analysis of inventory systems’, three main conclusions were presented. (1) The inventory models analysed in his paper demonstrate that the inventory policy derived from the discounted (PW) coat differs substantially from that given by the traditional undiscounted inventory analysis. (2) The difference between the two depends upon the discounting rate. The discounting causes the optimum order quantity and correspondingly the period length to vary monotonically with the discounting rate. (3) However, it is not influenced by the inventory system planning horizon. This paper first examines each conclusion and demonstrates why his conclusions are either unfounded or irrelevant to his analysis. Next, some crucial derivational errors in his exposition are demonstrated via corrected formulations. Finally, a net present value maximizing framework that is consistent with modern theory of financial analysis, is suggested for the economic analysis of inventory systems. 相似文献
77.
Electrophoretic patterns of fresh beef, pork, chicken, and turkey sarcoplasmic proteins were studied using thin layer agarose gel electro-phoresis. Creatine kinase isozyme MM and myoglobin bands were used to identify the species. Binary mixtures (5/95, 25175, 50150, 751 25, 9515, % by weight of each species) were also examined by their electrophoretic and densitometric patterns. Electrophoretic patterns remained stable at elevated pH (7.5), but were affected by low pH (4.7). The relative ratios of the bands which characterized each species changed in proportion to the species content in each binary mixture. These ratios make it possible to predict the approximate fraction of each species present in such mixtures. 相似文献
78.
Equivalent concentrations of polydextrose and sucrose had similar effects on phase transitions of wheat starch-water systems. Onset and peak gelatinization temperatures were increased similarly with the two solutes. This was true with varied water:starch ratios, varied concentrations of solute, and for batters prepared with the two solutes. Acesulfame K, cyclamate, and saccharin at low levels, as might be used in food products, had little effect on phase transitions of starch-water-solute systems. 相似文献
79.
Heat penetration experiments were carried out in a hot water bath with small blocks of a solid polycarbonate material cut into various shapes (cylinder, cube and oval) to obtain heat penetration factors for each shape. These factors, along with characteristic dimensions from the odd shapes were then used in the finite cylinder heat transfer model to predict accurately the temperature at the center of each block in response to measured dynamic bath temperatures. Results showed sufficiently good agreement between predicted and measured center temperature profiles to justify use of the finite cylinder model for rapid evaluation of process deviations in thermal processing of foods in odd-shaped containers. 相似文献
80.
Abstracts are not published in this journal
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献