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41.
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DM Wyatt 《Canadian Metallurgical Quarterly》1993,23(7):32U, 32Y-32Z passim
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It is well known that low levels of light element impurities, such as oxygen and nitrogen, can significantly modify phase
equilibria in conventional titanium alloys. However, although the role of nitrogen and oxygen as alpha stabilizers is well
established, little quantitative work exists in ternary and higher order systems. Moreover the effect of such elements on
equilibria with phases other than cx-and P-Ti is often unknown. The problems in measuring light elements at the microscopic
level adds to the difficulty of establishing partitioning, and old axioms are often transferred to new alloys with little
evidence that they are applicable. As part of a current program on titanium alloys, phase diagram modeling has been performed
for a variety of titanium alloys with additions of oxygen and nitrogen. This paper presents results for the system Ti-Al-V-O-(N,C)
with particular reference to the O additions to the commercially important alloy Ti-6A1-4V.
This paper was presented at the International Phase Diagram Prediction Symposium sponsored by the ASM/MSD Thermodynamics and
Phase Equilibria Committee at Materials Week, October 21–23,1991, in Cincinnati, OH. The symposium was organized by John Morral,
University of Connecticut, and Philip Nash, Illinois Institute of Technology. 相似文献
47.
Christine Di Massimo Paul A. Lant Aidan Saunders Gary A. Montague Ming T. Tham A. Julian Morris 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1992,53(3):265-277
The last decade has seen the development of a number of approaches for estimating those variables which are difficult to measure on-line in industrial process situations. Whilst a range of techniques is available, a common element is the use of process knowledge in the form of a system model. In the case of bioprocess systems, although a large range of models has been presented in the literature, their use in estimation schemes on an industrial scale has been limited. A number of reasons can be identified for their low level of utilisation. Of particular significance is the uncertainty which exists in quantifying system performance and the process-model mismatch which inevitably results. The level of ‘pre-defined model’ uncertainty, together with the knowledge gained during the course of the fermentation, serves to dictate estimator structure. The paper considers a range of estimation strategies and contrasts, through industrial applications, their performance characteristics and utility. 相似文献
48.
DM Haig A Percival J Mitchell I Green D Sargan 《Canadian Metallurgical Quarterly》1995,45(3-4):221-236
An in vitro culture system is described which allows an analysis of the signals responsible for the survival, growth and functional maturation of afferent lymph dendritic cells (ALDC), a subpopulation of migrating dermal dendritic cells involved in antigen carriage and presentation to T-cells. Purified ALDC survived and grew for up to 30 days in lymph node conditioned medium and survived 14 days in recombinant ovine (rov) TNF-alpha whereas none were detected after 24 h in rov GM-CSF, rov IFN-gamma or rh M-CSF. However, when rov GM-CSF was added to cultures along with rov TNF-alpha, increased numbers of ALDC compared with input numbers (growth) were recorded on Days 14 and 21. In contrast, when 50-200 units ml-1 of rov IFN-gamma were added to cultures of ALDC along with TNF-alpha or rov TNF-alpha plus rov GM-CSF, cell survival and growth was inhibited. Antibody blocking studies confirmed the cytokine specificity of these effects. ALDC cultured in rov TNF-alpha or rov TNF-alpha plus rov GM-CSF retained MHC Class-II and ov CD-1 antigen expression and accessory function for autologous ov CD-4 T-cell proliferation, although at reduced levels compared with freshly isolated cells. Neither fresh nor cultured ALDC expressed coagulation factor XIIIa. 相似文献
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HA Mook DM Paul BC Sales LA Boatner L Cussen 《Canadian Metallurgical Quarterly》1988,38(16):12008-12010