Solid state reactions between Ni3Al and SiC

1990 ◽  
Vol 5 (9) ◽  
pp. 1985-1994 ◽  
Author(s):  
T. C. Chou ◽  
T. G. Nieh
Keyword(s):  
Growth Rate ◽  
Solid State ◽  
Solid State Reactions ◽  
Growth Rate Constant ◽  
Cross Sectional ◽  
Rate Limiting Step ◽  
Nial Phase ◽  
Reaction Zones ◽  
Carbon Precipitation ◽  
Terminal Component

Solid state reactions between SiC and Ni3Al were studied at 1000°C for different times. Multi-reaction-layers were generated in the interdiffusion zone. Cross-sectional views of the reaction zones show the presence of three distinguishable layers. The Ni3Al terminal component is followed by NiAl, Ni5.4Al1Si2, Ni(5.4−x)Al1Si2 + C layers, and the SiC terminal component. The Ni5.4Al1Si2 layer shows carbon precipitation free, while modulated carbon bands were formed in the Ni(5.4−x)Al1Si2 + C layer. The NiAl layer shows dramatic contrast difference with respect to the Ni3Al and Ni5.4Al1Si2 layers, and is bounded by the Ni3Al/NiAl and Ni5.4Al1Si2/NiAl phase boundaries. The kinetics of the NiAl formation is limited by diffusion, and the growth rate constant is measured to be 2 ⊠ 10−10 cm2/s. The thickness of the reaction zone on the SiC side is always thinner than that on the Ni3Al side and no parabolic growth rate is obeyed, suggesting that the decomposition of the SiC may be a rate limiting step for the SiC/Ni3Al reactions. The carbon precipitates were found to exist in either a disordered or partially ordered (graphitic) state, depending upon their locations from the SiC interface. The formation of NiAl phase is discussed based on an Al-rejection model, as a result of a prior formation of Ni–Al–Si ternary phase. A thermodynamic driving force for the SiC/Ni3Al reactions is suggested.

Asymmetric synthesis of the N-terminal component of microginin: (2S,3R)-3-amino-2-hydroxydecanoic acid, its (2R,3R)-epimer and (3R)-3-aminodecanoic acid

1995 ◽  
Vol 6 (1) ◽  
pp. 165-176 ◽  
Author(s):  
Mark E Bunnage ◽  
Anthony J Burke ◽  
Stephen G Davies ◽  
Christopher J Goodwin
Keyword(s):  
Asymmetric Synthesis ◽  
Terminal Component

Isolation, absolute configuration and bioactivities of megastigmanes or C13 isonorterpinoides

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Cucumis Sativus ◽  
Absolute Configuration ◽  
Oxidative Cleavage ◽  
Juniperus Communis ◽  
Plant Source ◽  
Potential Activity ◽  
Terminal Component

Megastigmanes or C13 isonorterpenoids a terpene class of compounds, specially the title compounds are related to sesquiterpenoides but due to C13 skeleton also it is called as norterpenoides. Most of the megastimane compounds have been isolated from the plant source such as Cucumis sativus, Crotalaria zanzibarica, staphylea bumalda, Juniperus communis and Excoecaria cohinchinensis etc. Few reports were showing the megastimane compounds are showing potencial activity against scavenging radical (DPPH) and hepatoprotective activities. The classification of C13 norisoprenoides, are assumed to be apocarotenoides that is formed from the degradation of carotenoides by the action of carotenoides cleavage dioxygenases which have been isolated from various plants. The majority of the evidences for this assumption is the similarly between most megastigmanes and the terminal component of plant carotenoides. Because such compounds are generally not oxygenated at C7 but commonly oxygenated at C9 presumably as a result of the oxidative cleavage of the acyclic portion of caritenoides, the key step in megastigmanes formation has been thought to be transportion of oxygen from C9 to C7. Hence, based on the above information the C9 position and its absolute configuration is very important to get potential activity against various diseases, in this progression a lot of literature reports were showing the importance and absolute configuration at C9 position in megastigmanes or C13 norisoprenoides. In this review, we are reporting the chemistry, absolute configuration and bioactivities of megastigmanes or C13 norisoterpenoides. To our knowledge, this is the first review on megastimanes and its absolute configuration.

Terminal component of complement (C9) in the cerebrospinal fluid of patients with multiple sclerosis and neurologic controls

Neurology ◽  
1990 ◽  
Vol 40 (5) ◽  
pp. 855-855 ◽  
Author(s):  
M. Rodriguez ◽  
D. R. Wynn ◽  
T. K. Kimlinger ◽  
J. A. Katzmann
Keyword(s):  
Multiple Sclerosis ◽  
Cerebrospinal Fluid ◽  
Complement C9 ◽  
Terminal Component

A Novel Synthesis of Cyclohexylnorstatine Isopropyl Ester, the C-Terminal Component of a Renin Inhibitor

Heterocycles ◽  
1990 ◽  
Vol 30 (1) ◽  
pp. 299 ◽  
Author(s):  
Shiro Terashima ◽  
Yoshio Ito ◽  
Tetsuhide Kamijo ◽  
Hiromu Harada
Keyword(s):  
Renin Inhibitor ◽  
Isopropyl Ester ◽  
Novel Synthesis ◽  
Terminal Component
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