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1.
S. Y HO 《Journal of Materials Science》1997,32(19):5155-5161
A methodology for determining the response of rocket motor materials and bondlines to thermal loadings by measuring their
dynamic mechanical properties is reported. The critical temperatures at which debonding and/or propellant cracking occur and
the number of thermal cycles required to induce failure were evaluated. These results were compared with those from instrumented
rocket motors subjected to similar thermal loadings. A model, developed for fibre reinforced composites, was applied to the
propellant-inhibitor bimaterial obtained from a rocket motor. The internal energy dissipation due to a lack of perfect adhesion
at the propellant–inhibitor interface, tan δadh, was used to give an indication of the failure mode of the bondline (i.e., adhesive failure at the interface or cohesive
failure in the propellant) and the bond adhesion parameter, C, was related to the bond strength measured by rectangular bond-in-tension
tests.
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
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3.
E Prescott M Osler PK Andersen A Bjerg HO Hein K Borch-Johnsen P Lange P Schnohr J Vestbo 《Canadian Metallurgical Quarterly》1997,26(6):1214-1218
BACKGROUND: Two recent much cited publications have raised the concern that risk associated with cigarette smoking has so far been underestimated. In this study we wish to determine whether excess all-cause mortality associated with smoking has increased during the last 20-30 years in a study population representative of the general Danish population and whether any such changes relate to changes in smoking behaviour. METHODS: Pooled data from three prospective population studies conducted in Copenhagen with detailed information on smoking habits. A total of 31,194 subjects, 17,669 males and 13,525 females, initially examined between 1964 and 1992 with examinations repeated at intervals from 1-10 years, were followed until 1995 for all-cause mortality. Relative mortality risk in smokers versus never-smokers was calculated within periods of five calendar years and compared throughout the study period. RESULTS: Male smokers' exposure did not change during the study period whereas female smokers' exposure to tobacco increased in terms of age at smoking onset, quantity smoked and depth of inhalation. During follow-up 5744 males and 2900 females died. In males, death rate ratios (comparing continuous smokers with never-smokers) did not change in the study period. In females, ratios increased from 1964-1978 to 1979-1994 by a factor of 1.3 (95% confidence interval 1.0-1.8). CONCLUSIONS: In agreement with the observed changes in smoking habits, excess mortality in male smokers did not increase whereas excess mortality in female smokers increased slightly. 相似文献
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5.
With greater need for treating root surface lesions, dentinal adhesives are more in demand. For successful treatment, all factors--dentin, tooth, patient and materials--must be considered. 相似文献
6.
An extensive and systematic search strategy to determine the conformational profile of 12 cyclic disulfide-bridged opioid peptides with varying affinities at the delta receptor has been carried out to identify the structure that is recognized by the delta receptor for each analogue. The methods and procedures used here for the conformational search have already been validated for [D-Pen2,D-Pen5] enkephalin (DPDPE), one member of this family. Use of these methods led to a low-energy solution conformation of DPDPE in excellent agreement with all the geometric properties deduced from its solution nmr spectra. Each of the analogue was subjected to the same procedure, involving a combination of molecular dynamics simulations at high and low temperature. The study was repeated in two environmental conditions, an apolar environment, simulated by using a distance-dependent dielectric constant, and a polar environment by embedding the peptides in a high constant dielectric (epsilon = 80). An automated comparison of the different conformers based on their backbone rms and average distance between the key aromatic moieties was followed by graphic analysis using maximum structural overlap. The cross-comparison of the conformations for each analogue revealed a unique conformer that may be recognized by the delta receptor for each high-affinity analogue that permitted maintaining the critical elements required for recognition in a simple spatial orientation, while maximizing similarity in other regions. 相似文献
7.
FC Tulunay HO Onaran H Ergün A Ucar S Usanmaz K Embil M Tulunay 《Canadian Metallurgical Quarterly》1998,48(11):1068-1071
Phenprobamate (CAS 673-31-4) is a centrally acting skeletal-muscle relaxant agent. There are only two studies in the literature about the pharmacokinetics of phenoprobamate in man. The inconsistency between the results of these studies can be attributed partly to the different analytical methodologies used. A sensitive, specific and reproducible HPLC-assay, which may increase the reliability of the pharmacokinetic studies of phenprobamate in plasma, has been developed recently. The objective of this investigation was to assess the single-dose kinetics of phenprobamate in human and to determine the pharmacokinetic parameters of clinical and regulatory concern. The plasma pharmacokinetics of phenprobamate have been investigated following single oral administration at a dose of 800 mg in eleven healthy volunteers. 相似文献
8.
介绍了低铬耐热铸铁(RTcr2)的生产过程,用1.5t/h冲天炉和选择化学成分为:ω(cr)1.5%-1.8%,ω(C)3.0%~3.3%,ω(Si)2.0%~2.5%,ω(Mn)≤0.8%,ω(P)、ω(S)≤0.10%的铁液,生产现场严格控制底焦高度、铬铁块度,石灰石加入量等,生产的耐热铸铁完全满足了产品的各项性能要求。 相似文献
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10.
HO Klein 《Canadian Metallurgical Quarterly》1976,69(3):441-444
Ventricular premature beats (VPBs) appeared in a patient after pacemaker insertion for complete heart block secondary to acute myocardial infarction. Contrary to expectations, the frequency of VPBs was directly related to the basic pacemaker rate. The VPBs are either reentrant beats or represent VPBs arising from pacemaker cells with "slow-response" characteristics, which have been shown to become more automatic with increasing rates of electrical stimulation. This case documents the phenomenon of rate dependency of VPBs in man and discusses its practical importance. 相似文献