| The Synthesis of ROMP Homopolymers and Multi-Block Copolymers Containing Sugars |
14 JUN 95 |
10 pages |
| Authors:
K. Nomura; R. R. Schrock; MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF CHEMISTRY
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 | Ring-opened homopolymers of 1,2:3,4-di-O-isopropylidene-alpha-D- galactopyranos-6-O-yl- 5-norbomene-2-carboxylate (1) and bis(1,2:3,4-di-O- isopropylidene-alpha-D galactopyranos-6-O-yl)-5-norbornene-2,3-dicarboxylate (2) were prepared in toluene in a living manner using Mo(CHCMe2Ph)(N-2,6-i-Pr2C6H3) (O-t-Bu) 2 as the initiator. These homopolymers havelow PDI's (as low as 1.06) and molecular weights that are proportional to the number of monomers added. Various di-, tri-, and tetra-block copolymers containing 1, 2, methyltetracyclododecene (MID, 3), or trans-2,3- bis(trimethylsilyloxymethyl)- norborn-5-ene (4) could also be prepared and were ... |
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| The Effect of Temper Embrittlement on Hydrogen Embrittlement of 2-1/4Cr- 1Mo Steel |
FEB 84 |
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| Authors:
T. Fujii; R. Horita; K. Nomura
|
 | The effect of temper embrittlement on hydrogen embrittlement was investigated on 2.25Cr-1Mo steel for high-temperature and high-pressure vessels. The threshold stress intensity for hydrogen-stress cracking (HSC) was determined by immersing modified 1T-WOL specimens with and without step-cooling heat treatment into a hydrogen sulfide saturated 0.5% acetic acid solution. Temper embrittlement enhances the susceptibility to hydrogen embrittlement of grain boundary. |
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| Temperature Dependence of Hydrogen Diffusivity of 2-1/4Cr-1Mo Steel |
JAN 84 |
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| Authors:
T. Fujii; K. Nomura
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| Temperature dependence of hydrogen diffusivity in as-quenched 2.25Cr- 1Mo steel at temperatures of 25 to 300 C was investigated by a glycerine displacement increasing (GDI) method and a electrochemical method. In the determination of residual hydrogen by GDI method, hydrogen was charged at a austenitic temperature range under a hydrogen atmosphere and was discharged in isothermal baths at temperatures of 45 to 300 C. |
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| Kinetics of the Reaction Between Mg-23.2%Ni Eutectic Alloy and Hydrogen |
JAN 83 |
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| Authors:
E. Akiba; K. Nomura; S. Ono; Y. Mizuno
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| A mathematical expression is given to describe the reaction rate between the eutectic alloy Mg-23.3Ni and hydrogen in terms of the hydrogen-to- magnesium ratio, hydrogen and equilibrium pressures and rate constant. The reaction kinetics and time dependence are discussed. Diffusion of the reactant through the product layers is the rate-determining step. |
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| The Reaction of Hydrogen with Alloys of Vanadium and Titanium |
AUG 80 |
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| Authors:
S. Ono; K. Nomura; Y. Ikeda
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| Pressure-composition isotherms were measured for Ti-V-H systems between 80 C and 150 C and at pressures below 100 kgf cm(super -2). Hydride phases formed were identified by x-ray diffraction and corresponded to the monohydride and dihydride of the V-H(sub 2) system. |
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