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排序方式: 共有594条查询结果,搜索用时 15 毫秒
591.
Keiji Komatsu Tetsuo Sekiya Ayumu Toyama Yasuhiro Hasebe Atsushi Nakamura Masahiro Noguchi Yu Li Shigeo Ohshio Hiroki Akasaka Hiroyuki Muramatsu Hidetoshi Saitoh 《Journal of Thermal Spray Technology》2014,23(5):833-838
R2O3 (R = Y, Eu, Er) metal oxides were synthesized from metal–ethylenediaminetetraacetic acid (EDTA) complexes using a flame spray technique. As this technique enables high deposition rates, films with thickness of several tens of micrometers were obtained. Films of yttria, europia, and erbia phase were synthesized on stainless-steel substrates with reaction assistance by H2–O2 combustion gas. The oxide films consisted of the desired crystalline phase with micropores. The porosity of the films was in the range of 6–15%, varying with the metal used. These results suggest that the true density of the metal oxide obtained from metal–EDTA powder through the thermal reaction process plays an important role in achieving film with the desired porosity. 相似文献
592.
Origin of defect-insensitive emission probability in In-containing (Al,In,Ga)N alloy semiconductors 总被引:1,自引:0,他引:1
Chichibu SF Uedono A Onuma T Haskell BA Chakraborty A Koyama T Fini PT Keller S Denbaars SP Speck JS Mishra UK Nakamura S Yamaguchi S Kamiyama S Amano H Akasaki I Han J Sota T 《Nature materials》2006,5(10):810-816
Group-III-nitride semiconductors have shown enormous potential as light sources for full-colour displays, optical storage and solid-state lighting. Remarkably, InGaN blue- and green-light-emitting diodes (LEDs) emit brilliant light although the threading dislocation density generated due to lattice mismatch is six orders of magnitude higher than that in conventional LEDs. Here we explain why In-containing (Al,In,Ga)N bulk films exhibit a defect-insensitive emission probability. From the extremely short positron diffusion lengths (<4 nm) and short radiative lifetimes of excitonic emissions, we conclude that localizing valence states associated with atomic condensates of In-N preferentially capture holes, which have a positive charge similar to positrons. The holes form localized excitons to emit the light, although some of the excitons recombine at non-radiative centres. The enterprising use of atomically inhomogeneous crystals is proposed for future innovation in light emitters even when using defective crystals. 相似文献
593.
Katsuda T Shimahara K Shiraishi H Yamagami K Ranjbar R Katoh S 《Journal of Bioscience and Bioengineering》2006,102(5):442-446
To conserve energy in the production of astaxanthin by the green alga Haematococcus pluvialis, we utilized intermittent flashing light from blue light emitting diodes (LEDs) and investigated the effects of the incident light intensity (2-12 micromol m(-2) s(-1)), duty cycle (17-67%) and frequency (25-200 Hz) of flashing on the cell growth and astaxanthin production. In the above ranges, the final astaxanthin concentration under illumination by flashing light was significantly higher than that obtained under illumination with continuous light at the same incident intensity. For example, flashing light at an incident intensity of 8 micromol m(-2) s(-1) gave the same final astaxanthin concentration that was obtained under continuous light illumination at 12 micromol m(-2) s(-1), thus reducing energy consumption by 1/3. We therefore conclude that flashing light from blue LEDs is a promising illumination method for indoor algal cultivation using photobioreactors. 相似文献
594.
Yushi Fujita Atsushi Sakuda Yuki Hasegawa Minako Deguchi Kota Motohashi Ding Jiong Hirofumi Tsukasaki Shigeo Mori Masahiro Tatsumisago Akitoshi Hayashi 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(36):2302179
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 Li2S active material used in the positive electrode has a high theoretical capacity; consequently, nanocomposites composed of Li2S, 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 Li2S–Li2O–LiI positive electrode is developed in which the active material is dispersed in an amorphous matrix. Li2S–Li2O–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 Li2O–LiI provides nanoscale ion-conduction pathways during cycling that activate Li2S 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 Li2S–Li2O–LiI positive electrode. This study represents a major step toward the commercialization of all-solid-state Li/S batteries. 相似文献