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排序方式: 共有730条查询结果,搜索用时 328 毫秒
721.
722.
Kho YK Teoh WY Iwase A Mädler L Kudo A Amal R 《ACS applied materials & interfaces》2011,3(6):1997-2004
Visible-light-active BiVO(4) photocatalyst prepared by a one-step flame spray pyrolysis demonstrates the structural evolution from amorphous to crystalline scheelite-tetragonal and further to scheelite-monoclinic (the photocatalytic active phase). Up to 95% scheelite-monoclinic content, the rest being scheelite-tetragonal, can be achieved in situ by exposing the collection filter to higher flame temperature. Reasonable activity in terms of photocatalytic O(2) evolution was obtained with the increase in crystallinity and scheelite-monoclinic content. Although analogous postcalcination of BiVO(4) improves crystallization and phase transformation, it inevitably induces vacancy defects that are detrimental to the photocatalytic activity. Hence a facile aqueous acid treatment on the flame-made BiVO(4) is introduced, which in the presence of small addition of Bi and V promotes full transformation to scheelite-monoclinic and reduces charge trapping defects. As a result, the photocatalytic O(2) evolution activity was increased by a remarkable 5 folds compared to the best performing untreated flame-made BiVO(4). 相似文献
723.
Akihiko Terada Sheng Zhou Masaaki Hosomi 《Clean Technologies and Environmental Policy》2011,13(6):759-781
Until now, anaerobic ammonium oxidation (anammox) has been widely applied as an alternative method to the conventional nitrification–denitrification
pathway for biological nitrogen removal from wastewater. Since their discovery in a denitrifying fluidized bed reactor in
the Netherlands in the early 1990s, anammox bacteria have also been detected in natural environments. Anammox is one of the
newly found drivers known to contribute to the biogeochemical nitrogen cycle. In the marine environment, more than 50% of
nitrogenous compounds are reportedly converted into nitrogen gas via the anammox pathway. These observations were made using
state-of-the-art techniques for detecting anammox bacteria based on their lipids, small-subunit ribosomal RNA genes, functional
genes, and unique reaction pathways. The research objectives for anammox bacteria are quite diverse, ranging from the application
of anammox processes to various wastewater types, to anammox biochemistry and phylogeny, to elucidating how anammox bacteria
have evolved. Since the genome of the anammox bacterium Kuenenia stuttgaritiensis was deciphered, anammox bacteria have proved to be quite versatile. The next challenge is to enrich knowledge of anammox
bacterial physiology and phylogeny to improve their use in engineered and natural environmental systems and minimize nitrogen
loads to downstream water bodies. Furthermore, rapid startup of the anammox process for engineered systems is required to
broadly harness the benefits of anammox bacteria. This review article summarizes the physiology and phylogeny of anammox bacteria,
detection methods of anammox bacteria and reactions, the behavior of anammox bacteria in natural environments, and recent
developments in their use for engineered systems. 相似文献
724.
Toshihide Nabatame Masayuki KimuraHiroyuki Yamada Akihiko OhiTomoji Ohishi Toyohiro Chikyow 《Thin solid films》2012,520(8):3387-3391
We investigated flatband voltage (Vfb) behavior for several Hf-based high-k dielectrics, including HfO2, Mg-, and La-incorporated HfO2, HfSiOx, and Mg-, La-, and N-incorporated HfSiOx, during the reduction (forming gas annealing: FGA) and oxidation annealing (ODA) processes. A negative Vfb shift appeared in all high-k dielectrics as the FGA temperature increased. In contrast, a positive Vfb shift was observed after the introduction of additional oxygen into the high-k layer during ODA. The oxygen diffusion coefficient (D) values of all samples were estimated using Fick's law. The results showed that the D value of the HfO2 dielectric was five times as large as that of the HfSiOx dielectric in ODA at 400 °C. Furthermore, the Mg-, La-, and N- incorporated high-k dielectrics exhibited a larger D value compared with the pure high-k dielectrics. These results strongly suggest that the ionicity of high-k dielectrics, which we attribute to a large positive Vfb shift, enhances oxygen diffusion in the high-k layer. 相似文献
725.
What is believed to be a new technique that allows for the simultaneous measurement of 2D temperature and chemical species concentration profiles with high spatial resolution and fast time response was developed and tested successfully by measuring a thin layer of fuel vapor created over a volatile fuel surface. Normal propanol was placed in an open-top rectangular container, and n-propanol fuel vapor was formed over the propanol surface in a quiescent laboratory environment. An IR beam with a wavelength of 8-13 mum emitted from a heated plate and a He-Ne laser beam with a wavelength of 632 nm were combined and passed through the n-propanol vapor layer, and both beams were absorbed by the vapor layer. The absorption of the IR beam was recorded by an IR camera, and the He-Ne laser was used to form a holographic interferogram. Two-dimensional temperature and propanol vapor concentration profiles were, respectively, determined by the IR absorption and the fringe pattern associated with the holographic interferogram. This new measurement technique is a significant improvement over the dual wavelength holographic interferometry that has been used previously to measure temperature and fuel concentration, and it is ready for application under different types of fire and flame conditions. 相似文献
726.
Akihiko KATO Takako TAKITA Mitsuyoshi FURUHASHI Yukitaka MARUYAMA Akira HISHIDA 《Hemodialysis international. International Symposium on Home Hemodialysis》2010,14(2):226-232
Serum albumin, C‐reactive protein (CRP), and the intima‐medial thickness of the common carotid artery (CA‐IMT) are associated with clinical outcomes in hemodialysis (HD) patients. However, it remains unclear which parameters are more reliable as predictors of long‐term mortality. We measured serum albumin, CRP, and CA‐IMT in 206 HD patients younger than 80 years old, and followed them for the next 10 years. One hundred sixty‐eight patients (age: 57 ± 11 years, time on HD: 11 ± 7 years) were enrolled in the analyses. We divided all patients into three tertiles according to their albumin levels, and conducted multivariate analyses to examine the impact on 10‐year mortality. Seventy‐three (43.5%) patients had expired during the follow‐up. Serum albumin was significantly lower in the expired patients than in the surviving patients (3.8 ± 0.3 vs. 4.0 ± 0.3, P<0.01), while CRP (4.7 ± 5.0 vs. 2.8 ± 3.5 g/L, P=0.01) and CA‐IMT (0.70 ± 0.15 vs. 0.59 ± 0.11 mm, P<0.01) were significantly higher in the expired group. The multivariate analysis revealed that there was a significantly higher risk for total mortality in HD patients with serum albumin <3.8 g/dL (odds ratio 5.04 [95% CI: 1.30–19.60], P=0.02) when compared with those with albumin >4.1 g/dL. In contrast, CRP and CA‐IMT did not associate with total death. It follows from these findings that serum albumin is more superior as a mortality predictor compared with CRP and CA‐IMT in HD patients. 相似文献
727.
Daichi Yazaki Tokuhisa Kawawaki Daisuke Hirayama Masanobu Kawachi Kosaku Kato Sota Oguchi Yuichi Yamaguchi Soichi Kikkawa Yoshiya Ueki Sakiat Hossain D. J. Osborn Fumihiko Ozaki Shunsuke Tanaka Jun Yoshinobu Gregory F. Metha Seiji Yamazoe Akihiko Kudo Akira Yamakata Yuichi Negishi 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(34):2208287
For the realization of a next-generation energy society, further improvement in the activity of water-splitting photocatalysts is essential. Platinum (Pt) is predicted to be the most effective cocatalyst for hydrogen evolution from water. However, when the number of active sites is increased by decreasing the particle size, the Pt cocatalyst is easily oxidized and thereby loses its activity. In this study, a method to load ultrafine, monodisperse, metallic Pt nanoclusters (NCs) on graphitic carbon nitride is developed, which is a promising visible-light-driven photocatalyst. In this photocatalyst, a part of the surface of the Pt NCs is protected by sulfur atoms, preventing oxidation. Consequently, the hydrogen-evolution activity per loading weight of Pt cocatalyst is significantly improved, 53 times, compared with that of a Pt-cocatalyst loaded photocatalyst by the conventional method. The developed method is also effective to enhance the overall water-splitting activity of other advanced photocatalysts such as SrTiO3 and BaLa4Ti4O15. 相似文献
728.
Prof. Dr. Yoshitsugu Akiyama Kazunori Kimura Dr. Syuuhei Komatsu Dr. Tohru Takarada Prof. Dr. Mizuo Maeda Prof. Dr. Akihiko Kikuchi 《Chembiochem : a European journal of chemical biology》2023,24(1):e202200451
A colorimetric assay of DNA cleavage by bleomycin (BLM) derivatives was developed utilizing high colloidal stability on double-stranded (ds) DNA-modified gold nanoparticles (dsDNA-AuNPs) possessing a cleavage site. The assay was performed using dsDNA-AuNPs treated with inactive BLM or activated BLM (Fe(II)⋅BLM). A 10-min exposure in dsDNA-AuNPs with inactive BLM treatment resulted in a rapid color change from red to purple because of salt-induced non-crosslinking aggregation of dsDNA-AuNPs. In contrast, the addition of active Fe(II)⋅BLM retained the red color, probably because of the formation of protruding structures at the outermost phase of dsDNA-AuNPs caused by BLM-mediated DNA cleavage. Furthermore, the results of our model experiments indicate that oxidative base release and DNA-cleavage pathways could be visually distinguished with color change. The present methodology was also applicable to model screening assays using several drugs with different mechanisms related to antitumor activity. These results strongly suggest that this assay with a rapid color change could lead to simple and efficient screening of potent antitumor agents. 相似文献
729.
Yuri Mitsuhashi Shogen Matsumoto Akihiko Ito 《Journal of the American Ceramic Society》2023,106(9):5140-5146
The eutectic structure of metals and ceramics is the result of a self-organization phenomenon in which multiple solid phases solidify with an ordered structure from a liquid phase. Hence, a melt-solidification process was the only way to generate ordered structures in a ceramic eutectic system. Here, we prepared ordered structures of Y3Al5O12 (YAG)–Al2O3 composites via chemical vapor deposition in the YAG–Al2O3 eutectic system. Spatially periodic YAG rod and lamellar structures were generated in an alumina matrix homoepitaxially grown on the sapphire substrates on the Al2O3-rich side of the eutectic composition, whereas α-Al2O3 rod and lamellar structures were generated in a YAG matrix on the Y2O3-rich side. The results reveal that the pattern formation of ordered structures in a ceramic eutectic system can occur not only during in the melt-solidification process but also during the vapor deposition process. The Ce3+-doped YAG–Al2O3 composite film converts some of the blue light into yellow light, allowing some of it to pass through, and emitting white light. The Eu3+-doped YAG–Al2O3 composite film can be utilized as a scintillation screen for a high-resolution X-ray imaging test to see though a semiconductor storage device. 相似文献
730.
Yoshida Ibuki Yoshida Akihiko Hashimoto Masafumi Takahashi Kazuhiko 《Artificial Life and Robotics》2023,28(2):471-482
Artificial Life and Robotics - This paper presents a point-cloud mapping method using a light detection and ranging (LiDAR) mounted on a helmet worn by a rider of micro-mobility. The distortion in... 相似文献