It was found that copper powder after 20h of milling shows the formation of a number of mechanical twins. The observed twins belong to two types: multiple twins and high-order ones.It is suggested that Venables model ...It was found that copper powder after 20h of milling shows the formation of a number of mechanical twins. The observed twins belong to two types: multiple twins and high-order ones.It is suggested that Venables model on mechanical twins in face-center-cubic metals is reasonable in this case. The generation of mechanical twins could be explained as follows:the shear stress (P_(max)) induced by ball milling exceeds the critical shear stress for twinning(τ):the grain size decreases to a critical value below which twinning rather than slip is the preferred mode of deformation as well as the strain rate induced by ball milling is high.展开更多
A kind of new catalyst-carbonaceous catalyst-for CH_(4)-CO_(2) reformation has been developed in our laboratory.The effect of both oxygen-bearing functional group such as phenolic hydroxyl,carbonyl,carboxyl,and lacton...A kind of new catalyst-carbonaceous catalyst-for CH_(4)-CO_(2) reformation has been developed in our laboratory.The effect of both oxygen-bearing functional group such as phenolic hydroxyl,carbonyl,carboxyl,and lactonic,and ash such as Fe_(2)O_(3),Na_(2)CO_(3),and K_(2)CO_(3) in the carbonaceous catalyst on the CH_(4)-CO_(2) reforming has been investigated with a fixed-bed reactor.It has been found that the carbonaceous catalyst is an efficient catalyst on CO_(2)-CH_(4) reforming.With the decrease of oxygen-bearing functional group,the catalytic activity of carbonaceous catalyst decreases quickly.The oxygen-bearing functional groups play a significant role in the carbonaceous-catalyzed CO_(2)-CH_(4) reforming;the ash components in carbonaceous catalyst also have an important influence on the CO_(2)-CH_(4) reforming.Fe_(2)O_(3),Na_(2)CO_(3),and K_(2)CO_(3) in the ash can catalyze the CO_(2)-CH_(4) reforming reaction;CaO has little effect on CO_(2)-CH_(4) reforming reaction.CaO can catalyze the gasification between carbonaceous catalyst and CO_(2);Al_(2)O_(3) and MgO inhibit the CO_(2)-CH_(4) reforming.展开更多
文摘It was found that copper powder after 20h of milling shows the formation of a number of mechanical twins. The observed twins belong to two types: multiple twins and high-order ones.It is suggested that Venables model on mechanical twins in face-center-cubic metals is reasonable in this case. The generation of mechanical twins could be explained as follows:the shear stress (P_(max)) induced by ball milling exceeds the critical shear stress for twinning(τ):the grain size decreases to a critical value below which twinning rather than slip is the preferred mode of deformation as well as the strain rate induced by ball milling is high.
基金the National Basic Research Program of China(2005CB221202)Shanxi Provincial Natural Science Foundation(20051020)for financial support of the present study。
文摘A kind of new catalyst-carbonaceous catalyst-for CH_(4)-CO_(2) reformation has been developed in our laboratory.The effect of both oxygen-bearing functional group such as phenolic hydroxyl,carbonyl,carboxyl,and lactonic,and ash such as Fe_(2)O_(3),Na_(2)CO_(3),and K_(2)CO_(3) in the carbonaceous catalyst on the CH_(4)-CO_(2) reforming has been investigated with a fixed-bed reactor.It has been found that the carbonaceous catalyst is an efficient catalyst on CO_(2)-CH_(4) reforming.With the decrease of oxygen-bearing functional group,the catalytic activity of carbonaceous catalyst decreases quickly.The oxygen-bearing functional groups play a significant role in the carbonaceous-catalyzed CO_(2)-CH_(4) reforming;the ash components in carbonaceous catalyst also have an important influence on the CO_(2)-CH_(4) reforming.Fe_(2)O_(3),Na_(2)CO_(3),and K_(2)CO_(3) in the ash can catalyze the CO_(2)-CH_(4) reforming reaction;CaO has little effect on CO_(2)-CH_(4) reforming reaction.CaO can catalyze the gasification between carbonaceous catalyst and CO_(2);Al_(2)O_(3) and MgO inhibit the CO_(2)-CH_(4) reforming.
