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991.
The failure characteristic of graphite polyetheretherketone (Gr/PEEK) under compression with a centrally located circular discontinuity was investigated through experimentation and a nonlinear ply-by-ply finite element technique. The stacking sequence of the laminates investigated were: [0 °16], [90 °16], [±45 °]4S [0 °/90 °]4S, and [0 °/ ± 45 0°/90 °]2S. In the experimentation, [90 °]16, [0 °/90 °]4S, and [0 °/ ±45 °/90 °]2S laminates, as well as three of the [0 °]16, failed due to a crack that was normal to the loading direction and initiated from the edge of the hole progressing to the outer edges of the specimen. The [±45 °]4S specimens failed to support the load due to an internal crack that originated from the hole's edge and then traveled at an angle of about 42% to the direction of loading. The finite element method used to analytically model the failure of Gr/PEEK accurately modeled the response of the specimens tested experimentally. 相似文献
992.
Three roller/blade tachometric chamber transducers, with capacities of 2, 10, and 20 cm3/rev, have been designed for measuring low flow rates.
Translated from Izmeritel'naya Tekhnika, No. 5, pp. 37–41, May, 1996. 相似文献
993.
M. Bennahmias H. B. Radousky T. J. Goodwin R. N. Shelton 《Journal of Electronic Materials》1993,22(10):1189-1193
Magnetic characterization has been performed on the members of the cuprateniobate RBa2Cu2NbO8 (R = Pr, Nd, and La) series and R1.5Ce0.5Sr2Cu2NbO10 (R = Pr, Eu, Nd, and Sm) series. The PrBCNO samples show a signature in the magnetization of a magnetic ordering at 12K.
The PrCSCNO sample is nonsuperconducting and shows two distinct orderings at 17K and 53K. No such magnetic phase transition
is observed down to 2K in the Nd and La based RBCNO materials or the Nd, Sm, and Eu based RCSCNO materials. Measurements of
the lower critical field curve, dc irreversibility line, and critical curent densities are reported for each of the superconducting
NdCSCNO, SmCSCNO, and EuCSCNO compounds. 相似文献
994.
A mathematical model describing the motion of a highly concentrated coke-ash mixture in the pneumatic transport region within the free board zone of a circulating fluidized bed reactor was developed earlier in [1–3]. In the present work it is extended to the case of a nonisothermal flow with heterogeneous combustion of carbon. Equations of mass, momentum, and energy conservation are obtained for the gas components and the coke fractions. Distinctive features of the heat transfer, combustion, and particle motion are investigated numerically.Institute of Problems of Energy Conservation, Academy of Sciences of Ukraine, Kiev, Ukraine. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 67, Nos. 1–2, pp. 32–38, July–August, 1994. 相似文献
995.
We investigated changes in the anterior tibial muscle during lengthening of the lower leg in rabbits. In 37 rabbits, an osteotomy of the right middle tibia was performed and was fixed by a unilateral external fixator. The rabbits were randomized into 6 groups. In groups 1, 2, and 3 the tibiae were distracted 0.5 mm/day. In groups 1 and 2, the rabbits were killed after 14 and 28 days of distraction, respectively, and in group 3 after 28 days of distraction, followed by 14 days of rest. Groups 1a, 2a, and 3a served as controls. They were treated similarly as groups 1, 2, and 3, but no distraction was performed. Proliferating cell nuclei were labeled with 5-bromo-2-deoxyuridine and were identified by immunohistochemical staining. The weight of the muscle was measured. During bone lengthening the muscle showed signs of growth, as indicated by increasing weight and number of proliferating cell nuclei. This was observed only during lengthening and it ceased when the lengthening was stopped. 相似文献
996.
Successful reconstruction after portal vein resection in extended liver surgery has been performed by end-to-end anastomosis, patch, or graft interposition. Previously described techniques to obtain venous grafts for portal replacement necessarily have either an additional incision or an unsuitable diameter. We developed a new method of portal vein replacement using the excised hepatic vein. This technique can be applied in major liver resections for tumors infiltrating the portal vein that have a safe distance from the hepatic vein. 相似文献
997.
M Rivet-Bastide G Vandecasteele S Hatem I Verde A Bénardeau JJ Mercadier R Fischmeister 《Canadian Metallurgical Quarterly》1997,99(11):2710-2718
EHNA (Erythro-9-[2-hydroxy-3-nonyl]adenine) is a wellknown inhibitor of adenosine deaminase. Recently, EHNA was shown to block the activity of purified soluble cGMPstimulated phosphodiesterase (PDE2) from frog, human, and porcine heart with an apparent Ki value of approximately 1 microM and with negligible effects on Ca2+/calmodulin PDE (PDE1), cGMP-inhibited PDE (PDE3), and low Km cAMP-specific PDE (PDE4) (Méry, P.F., C. Pavoine, F. Pecker, and R. Fischmeister. 1995. Mol. Pharmacol. 48:121-130; Podzuweit, T., P. Nennstiel, and A. Muller. 1995. Cell. Signalling. 7:733- 738). To investigate the role of PDE2 in the regulation of cardiac L-type Ca2+ current (ICa), we have examined the effect of EHNA on ICa in freshly isolated human atrial myocytes. Extracellular application of 0.1-10 microM EHNA induced an increase in the amplitude of basal ICa ( approximately 80% at 1 microM) without modification of the current-voltage or inactivation curves. The maximal stimulatory effect of EHNA on ICa was comparable in amplitude with the maximal effect of isoprenaline (1 microM), and the two effects were not additive. The effect of EHNA was not a result of adenosine deaminase inhibition, since 2'-deoxycoformycin (1-30 microM), another adenosine deaminase inhibitor with no effect on PDE2, or adenosine (1-10 microM) did not increase ICa. In the absence of intracellular GTP, the substrate of guanylyl cyclase, EHNA did not increase ICa. However, under similar conditions, intracellular perfusion with 0.5 microM cGMP produced an 80% increase in ICa. As opposed to human cardiomyocytes, EHNA (1-10 microM) did not modify ICa in isolated rat ventricular and atrial myocytes. We conclude that basal ICa is controlled by PDE2 activity in human atrial myocytes. Both PDE2 and PDE3 may contribute to keep the cyclic nucleotides concentrations at minimum in the absence of adenylyl and/or guanylyl cyclase stimulation. 相似文献
998.
Activation energy of electron-stimulated quenching of the photoluminescence of n-type porous silicon
The degradation of photoluminescence of porous silicon by kilovolt electrons and the mechanism and activation energy of this
process have been investigated. Quantitative relations between the integral intensity of the photoluminescence and the irradiation
dose and substrate temperature are obtained. The mechanism of the process is discussed and its activation energy is determined.
Pis’ma Zh. Tekh. Fiz. 23, 44–50 (September 26, 1997) 相似文献
999.
R Levy F Najioullah B Keppi D Thouvenot S Bosshard J Lornage B Lina JF Guerin M Aymard 《Canadian Metallurgical Quarterly》1997,68(5):820-825
This paper presents the results of in vivo measurements on a worker from a fuel reprocessing plant who was involved in an actinide intake. The results revealed that false indications of an actinide lung burden could arise from a contaminant present elsewhere in the chest region. Consequently, it is important that lung monitoring programs for occupational workers handling actinides are conducted with this caution in mind and that due consideration is given even in cases of minor cuts/wounds in order to rule out substantial overestimation of internal radiation doses. 相似文献
1000.
This case report describes an accessory hepatic duct (AHD) identified by intraoperative cholangiography during excisional surgery of a choledochal cyst (CC). The accessory duct was divided and reconstructed successfully to the Roux-en-Y jejunal loop. The postoperative course was uneventful, and follow-up abdominal sonography revealed neither evidence of biliary tract obstruction nor atrophic changes of the liver. It is advocated that an AHD should be meticulously reconstructed if it is divided during excisional surgery of a CC. 相似文献