ABSTRACT
All-solid-state lithium-sulfur (Li/S) batteries are promising next-generation energy-storage devices owing to their high capacities and long cycle lives. The Li2 S active material used in the positive electrode has a high theoretical capacity; consequently, nanocomposites composed of Li2 S, solid electrolytes, and conductive carbon can be used to fabricate high-energy-density batteries. Moreover, the active material should be constructed with both micro- and nanoscale ion-conduction pathways to ensure high power. Herein, a Li2 S-Li2 O-LiI positive electrode is developed in which the active material is dispersed in an amorphous matrix. Li2 S-Li2 O-LiI exhibits high charge-discharge capacities and a high specific capacity of 998 mAh g-1 at a 2 C rate and 25 °C. X-ray photoelectron spectroscopy, X-ray diffractometry, and transmission electron microscopy observation suggest that Li2 O-LiI provides nanoscale ion-conduction pathways during cycling that activate Li2 S and deliver large capacities; it also exhibits an appropriate onset oxidation voltage for high capacity. Furthermore, a cell with a high areal capacity of 10.6 mAh cm-2 is demonstrated to successfully operate at 25 °C using a Li2 S-Li2 O-LiI positive electrode. This study represents a major step toward the commercialization of all-solid-state Li/S batteries.
ABSTRACT
Speaking lesson is an effective way and teaching skill to prepare lessons for the teaching of anatomy. Taking the speaking lesson design of lecture teaching of the neck as an example, this article shows the teaching of topographic anatomy for "5+3" integrated clinical medical students. Adhering to the teaching concept of "student-centered", we have launched the theoretical teaching of "problem-centered discussion" and the experimental teaching of "operator responsibility system" in groups, with the "thanksgiving" humanistic education running through the whole process of theoretical and experimental courses. The teaching is a good way to cultivate the students' gratitude consciousness and humanistic quality, self-learning ability, critical thinking ability, communication and expression ability, hands-on operation ability and teamwork spirit, which has laid a solid foundation for training medical professionals in the new era.
ABSTRACT
Aging changes of somatostatin (SS) mRNA-positive neurons in the dorsal hippocampus of old rats were studied by in situ hybridization histochemistry and image analysis. In the young rats,SS mRNA-positive cell bodies were mainly located in the pyramidal and polymorphic cell layers of the CA1 and CA2 regions, and in the strata radiatum and polymorphic cell layer of the CA3 region, and in the polymorphic cell layer of dentate gyrus. In the old rats,SS mRNA-positive cell bodies were concentrated in the polymorphic cell layer and denate gyrus. A marked decrease of number of SS mRNA-positive cell bodies and a significant increase of gray value of SS mRNA-positive cell bodies were found in the dorsal hippocampus and dentate gyrus of the old rats as compared with the young rats. No significant age difference in the sectional area of SS mRNA-positive cell bodies was observed in the dorsal hippocampus. The results showed that there were apparent changes with aging of the SS mRNA-positive cell bodies in the dorsal hippocampus of the rats. The significance of the changes remains to be studied further.
