The electrical conductivity of post-perovskite in Earth's D' layer     

Ohta K  Onoda S  Hirose K  Sinmyo R  Shimizu K  Sata N  Ohishi Y  Yasuhara A 《Science (New York, N.Y.)》2008,320(5872):89-91

Recent discovery of a phase transition from perovskite to post-perovskite suggests that the physical properties of Earth's lowermost mantle, called the D' layer, may be different from those of the overlying mantle. We report that the electrical conductivity of (Mg0.9Fe0.1)SiO3 post-perovskite is >10(2) siemens per meter and does not vary greatly with temperature at the conditions of the D' layer. A post-perovskite layer above the core-mantle boundary would, by electromagnetic coupling, enhance the exchange of angular momentum between the fluid core and the solid mantle, which can explain the observed changes in the length of a day on decadal time scales. Heterogeneity in the conductivity of the lowermost mantle is likely to depend on changes in chemistry of the boundary region, not fluctuations in temperature.  相似文献   

Plasticization of cellulose derivatives by reactive plasticizers II: characterization of plasticized cellulose acetates and their biodegradability     

Mariko Yoshioka  Katsuya Okajima  Tomoko Miyazaki  Nobuo Shiraishi 《Journal of Wood Science》2000,46(1):22-31

A plasticization method for cellulose acetates (CAs) has been developed that is based on the reaction with dibasic acid anhydrides and monoepoxides during the melting processing. As a continuation of the discussion in the previous report, additional evidence is presented for the role of grafting oligoesters onto cellulose acetates to prevent the bleeding of homo-oligoesters from the inside of molded articles to their surface. Based on these results, a method for enhancing the amount of grafting has been pursued by varying the combination of dibasic acid anhydrides and monoepoxides. The resulting reactive meltprocessing method allows preparation of biodegradable cellulosic plastics using practical process conditions. Higher biodegradability has been found for the oligoester-grafted CAs than for the unmodified parent CAs.  相似文献   

Effect of dietary medicinal herbs on lipid metabolism and stress recovery in red sea bream <Emphasis Type="Italic">Pagrus major</Emphasis>     

Seung-Cheol Ji  Osamu Takaoka  Si-Woo Lee  Jae-Ho Hwang  Yang-Su Kim  Katsuya Ishimaru  Manabu Seoka  Gwan-Sik Jeong  Kenji Takii 《Fisheries Science》2009,75(3):665-672

The effect of dietary medicinal herbs on lipid metabolism and stress recovery was investigated in red sea bream Pagrus major. Fish (mean body weight 24.0 ± 0.2 g) were fed on test fish meal diets supplemented with either Massa Medicata (Mm), Crataegi Fructus (Cf), Artemisia capillaries (Ac), or Cnidium officinale (Co), or with a mixture of the four herbs (HM) for 12 weeks. A control group was fed a diet without herbs in the same manner. A high survival rate was observed in the herbal diet groups. The final mean body weight, feed efficiency, protein efficiency ratio, and apparent protein and lipid retention in the Ac, Co, and HM groups were higher than those in the control and Mm groups. Final carcass, hepatic lipid and triglyceride contents, and plasma triglyceride and nonesterified fatty acid levels were lower in the Ac, Co, and HM groups compared to those of control and Mm groups. However, final hepatic phospholipid, plasma phospholipid, and high density lipoprotein cholesterol levels were higher in the Ac, Co, and HM diets groups than in the control and Mm groups. The Cf, Co, Ac, and HM groups showed faster recovery time in the 2-phenoxyethanol anesthesia test and a higher recovery rate in the 10-min air exposure test than those of the control and Mm groups. Moreover, the Cf, Ac, Co, and HM diet groups had a significantly lower plasma cortisol level than the control and Mm diet group, but the glucose level in the herbal diet groups was higher than that in the control group after a 1-h air exposure. These results indicate that the addition of medicinal herbs to the fish diet improved lipid utilization and stress recovery in red sea bream.  相似文献