Graphene oxide and graphene based catalysts in photochemical ractions

Graphene has impressible absorbing ability and its electron transmission capacity makes it a great prosperity in many science horizons. In this study graphene or graphite nitride has been employed as a carrier in order to modify TiO2, ZnO and Ta2O5 photocatalysts.Graphene modified TiO2 particles were obtained by a sol-gel method from titanium isoproproxide (or P25) and reduced graphene oxide (RGO). The X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), UV-vis diffuse reflectance (UV-vis DRS) and thermo gravimetric differential thermal analysis (TG-DTA) were investigated over the samples. The diffuse reflectance spectra (DRS) studies indicate that G-TiO2 has a significant light absorption increasing and red shift of absorption peak. G-TiO2 photocatalyst could decompose methylene blue under visible light (> 430 nm). G-TiO2 synthesised from titanium isoproproxide presented better activity than G-TiO2 (P25). The catalysts could also produce ●OH and [O2]- radicals via electron scavengers (peroxymonosulphate, peroxydisulphate and hydrogen peroxide) to enhance degradation process with visible illumination.ZnO loaded RGO photocatalysts were synthesized through Zn powder and graphite oxide. The structural, morphological, and physicochemical properties of the samples were thoroughly investigated by XRD, FT-IR, FE-SEM, UV-visible DRS, TG-DTA, and Raman spectroscopy. Zn powder could successfully reduce GO and ZnO was obtained simultaneously by one-step hydrothermal method. RGO-ZnO photocatalysts could bleach MB under UV-vis illumination.Three different compounds: ammonia, graphene and C3N4 were utilized to dope tantalum pentoxide photocatalyst. Catalysts were analyzed by X-ray diffraction, UV–vis diffuse reflectance spectra and FTIR spectroscopy. The photocatalytic behavior was thorough investigated in bleaching methylene blue under UV-visible illuminations; the modified catalysts could decompose methylene blue, showing better activity than undoped Ta2O5. However, only N-doped Ta2O5 will show activity under visible light

A comparative study of reduced graphene oxide modified TiO2, ZnO and Ta2O5 in visible light photocatalytic/photochemical oxidation of methylene blue

Reduced graphene oxide (rGO) was applied to prepare various composites of rGO/photocatalyst of G/TiO2, G/ZnO and G/Ta2O5, using titanium (IV) isopropoxide, Zn powder and commercial Ta2O5 powder as photocatalyst precursors, respectively. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric-differential thermal analysis (TG-DTA) and UV–vis diffuse reflectance (UV–vis DRS) were employed to investigate the crystal structure, morphology, surface groups, rGO loading, and optical properties of the produced composites. The photocatalytic activities of the composites under UV–vis and visible light were studied in degradation of methylene blue (MB). G/Ta2O5 showed an enhanced efficiency under UV–vis irradiation. G/TiO2 demonstrated an effective degradation of MB under visible light. The effects of various oxidants, peroxymonosulfate (PMS), peroxydisulfate (PDS) and hydrogen peroxide (H2O2) on MB degradation were thoroughly investigated. H2O2 was a promising oxidant for promoting MB degradation under visible light. The mechanism of the enhanced efficiency in the system of G/TiO2+ vis + H2O2 was discussed

Multi-microjoule GaSe-based mid-infrared optical parametric amplifier with an ultra-broad idler spectrum covering 4.2-16 {\mu}m

We report a multi-microjoule, ultra-broadband mid-infrared optical parametric amplifier based on a GaSe nonlinear crystal pumped at ~2 {\mu}m. The generated idler pulse has a flat spectrum spanning from 4.5 to 13.3 {\mu}m at -3 dB and 4.2 to 16 {\mu}m in the full spectral range, with a central wavelength of 8.8 {\mu}m. The proposed scheme supports a sub-cycle Fourier-transform-limited pulse width. A (2+1)-dimensional numerical simulation is employed to reproduce the obtained idler spectrum. To our best knowledge, this is the broadest -3 dB spectrum ever obtained by optical parametric amplifiers in this spectral region. The idler pulse energy is ~3.4 {\mu}J with a conversion efficiency of ~2% from the ~2 {\mu}m pump to the idler pulse.Comment: 5 pages, 5 figure

K-ras/PI3K-Akt Signaling Is Essential for Zebrafish Hematopoiesis and Angiogenesis

The RAS small GTPases orchestrate multiple cellular processes. Studies on knock-out mice showed the essential and sufficient role of K-RAS, but not N-RAS and H-RAS in embryonic development. However, many physiological functions of K-RAS in vivo remain unclear. Using wild-type and fli1:GFP transgenic zebrafish, we showed that K-ras-knockdown resulted in specific hematopoietic and angiogenic defects, including the impaired expression of erythroid-specific gene gata1 and ße3-hemoglobin, reduced blood circulation and disorganized blood vessels. Expression of either K-rasC40 that links to phosphoinositide 3-kinase (PI3K) activation, or Akt2 that acts downstream of PI3K, could rescue both hematopoietic and angiogenic defects in the K-ras knockdown. Consistently, the functional rescue by k-ras mRNA was significantly suppressed by wortmannin, a PI3K-specific inhibitor. Our results provide direct evidence that PI3K-Akt plays a crucial role in mediating K-ras signaling during hematopoiesis and angiogenesis in vivo, thus offering new targets and alternative vertebrate model for studying these processes and their related diseases

類義副詞の文体を測る試み : 「まったく」・「ぜんぜん」・「すこしも」・「ちっとも」を例に

Toyo University会議名: 言語資源活用ワークショップ2019, 開催地: 国立国語研究所, 会期: 2019年9月2日−4日, 主催: 国立国語研究所 コーパス開発センター本発表はコーパスを用いて副詞の語彙レベルの文体を測る方法を試みるものである。4つの類義副詞、「まったく」「ぜんぜん」「すこしも」「ちっとも」を対象に、8つの形態的指標に基づき、「硬度」と「あらたまり」という2次元的な尺度を交差させることによって類義副詞の文体的な位置づけを明らかにした。2次元に分けた結果、4つの副詞がそれぞれの象限に収まった。「まったく」は硬度が高く、あらたまり度も高い。「ぜんぜん」は硬度はやや高いが、あらたまり度が低い。「すこしも」は硬度は低いが、あらたまり度が高い。そして、「ちっとも」は硬度も低く、あらたまり度も低いという結果である。一方、「硬度」という軸から見れば、「まったく」と「ぜんぜん」は近く、「すこしも」と「ちっとも」は似ているが、「あらたまり度」から見れば、「まったく」と「すこしも」は近く、「ぜんぜん」と「ちっとも」の文体がより似ていることが覗えた。「まったく」と「ちっとも」は最も距離が離れていることが分かった