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Narendra B. Dahotre T. Dwayne McCay Mary Helen McCay 《Materials and Manufacturing Processes》1994,9(3):447-466
A Laser Induced Liquid Phase Reaction Synthesis Assisted Joining technique is employed for SiC-particulate/Al-alloy composite to produce joints. Joints in SiC/Al-alloy composite are produced by synthesis of suitable material product as a result of interaction between composite and Ti (or Ti-alloy) reactive filler material induced by laser energy in the joint region. Such reaction product minimizes or eliminates the formation of deleterious aluminum carbide phase in the joint region depending upon the type and nature of die interfacial reactive filler material and also the laser processing parameters. A laser beam is utilized to both synthesize the interfacial reactant mixture and to heat the base material adjacent to the joint region to minimize the thermal stresses. The technique along with suitable filler material, further can be extended to a variety of metal matrix composite systems including combinations of Gr/Al, B/Al, B4C/Mg, Steel/Al, W/Al, Al2 O3 and Gr/Cu which are excellent for use in various automotive, aerospace and electronic applications. Preliminary observations describing the proof of concept of laser induced reaction joining of metal matrix composites are reported 相似文献
54.
A new model of the medical record is introduced which can incorporate context, structure, process and use of the medical record within a single narratological framework. It is claimed that the analysis of narrative and, in particular, the study of the story metaphor can provide a theoretical model which provides coherence within the broad discipline of Medical Informatics. It is argued that this framework maintains different levels of abstraction, is useful for teaching and clinical practice, and that its concepts can be readily understood by those in both lay and technical healthcare professions. 相似文献
55.
Reviews evidence concerning the congruence of the inductive and deductive models in logic and presents support for this congruence in the context of new test items designed to exemplify general-to-particular induction. Data from the Professional and Administrative Career Examination corroborate the logical foundations of deduction and induction as convergent models. Factor analysis of the items demonstrated factorial convergence, which lends additional support to the postulate of convergence. Implications for the understanding of cognitive processes and for psychometric practice are discussed in relation to such issues as the use of verbal and nonverbal test media, redundancy of measurement, and problem-solving strategies. (50 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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Using newly developed test equipment, the fatigue behavior of nylon 66 monofilaments was studied under two loading conditions, pure bending or simple torsion. For each mode, results are expressed in terms of the measured decay in stiffness with numbers of cycles over a range of maximum applied strain levels. Fatigue lifetimes are presented in S–N format where the log number of cycles of fatigue for a 40% decay in stiffness (N) is plotted as a function of applied strain (S). The failure mechanism for these fibers in each fatigue mode reflects the morphology of semicrystalline-oriented synthetic fibers. In torsion, many longitudinal cracks form around the perimeter of a fiber as the result of cleavage of the relatively weak interfibrillar bonds in nylon 66. In bending, cracks form within kink band boundaries and grow at an oblique angle to the fiber axis. © 1992 John Wiley & Sons, Inc. 相似文献
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Contends that tests in repeated-measures designs based on MANOVA are free of sphericity assumptions, and with modern computing software, MANOVA is straightforward to use, even for complex designs and nontraditional hypotheses. A general strategy for implementing MANOVA within statistical computing packages is presented. Regular (preplanned) tests and simultaneous (post hoc) tests are illustrated for a variety of designs and hypotheses. Optimal contrasts for unbalanced repeated measures designs are appended. (33 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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Our previous findings have shown that the developmental genes Pax7 and Pax3 are differentially methylated; the gene region that encodes the paired domain is hypomethylated, whereas the region that encodes the homeodomain is hypermethylated. For this reason, the known DNA sequence between the paired and homeoboxes was analysed for the presence of a conserved DNA motif to which a modifying protein could bind in order to direct the methylation or demethylation of surrounding gene sequences. The octapeptide-encoding region was found to contain several nucleotides that were highly conserved throughout the Pax gene family from phylogenetically distant species. The most conserved nucleotides are thought to comprise a motif TN8TCCT where N8=any combination of eight nucleotides. A conserved octapeptide-like-encoding sequence containing the TN8TCCT motif was also found in non-Pax genes of higher eukaryotes and in the non-coding strand of plants. Moreover, differential methylation seems to be associated with the presence of the TN8TCCT motif in p53 and the human oestrogen receptor genes. The presence of the TN8TCCT motif within an octapeptide-like-encoding sequence in human T-cell leukaemia virus type 1 might suggest that the putative recognition motif may have been introduced into various host genomes via some form of retroviral agent. 相似文献
59.
Mary S Patil GV Kulkarni AV Kulkarni MJ Joshi SR Mehendale SS Giri AP 《Proteomics. Clinical applications》2012,6(1-2):79-90
The coevolution of genomics and proteomics has led to advancements in the field of diagnosis and molecular mechanisms of disease. Proteomics is now stepping into the field of obstetrics, where early diagnosis of pregnancy complication such as preeclampsia (PE) is imperative. PE is a multifactorial disease characterized by hypertension with proteinuria, which is a leading cause of maternal and neonatal morbidity and mortality occurring in 5-7% of pregnancies worldwide. This review discusses the probable molecular mechanisms that lead to PE and summarizes the proteomics research carried out in understanding the pathogenicity of PE, and for identifying the candidate biomarker for diagnosis of the disease. 相似文献