Utsunomiya University

About: Utsunomiya University is a education organization based out in Utsunomiya, Japan. It is known for research contribution in the topics: Laser & Holography. The organization has 4139 authors who have published 6812 publications receiving 91975 citations. The organization is also known as: Utsunomiya daigaku.

Thermodynamic Study on Surface Adsorption and Micelle Formation of Poly(ethylene glycol) Mono-n-tetradecyl Ethers

Abstract: We present the temperature dependence of adsorption and micelle formation of oxyethylenated nonionic surfactants of the general formula C14En with n = 1, 2, 3, 4, and 8 by surface tension measurements. It is found that for the surfactants with a longer ethylene oxide (EO) chain, the critical micelle concentration (cmc) decreases, and the surface excess concentration (Γmax) increases with increasing temperature. But for C14E1, which bears only one EO unit, the cmc values initially increase and then decrease while the Γmax values gradually decrease with increasing temperature. Thus, the cmc−temperature data can be defined as a Λ-shaped curve, which is in striking contrast to the usual behavior of nonionic surfactants. This behavior is just the opposite trend of the usual behavior of ionic surfactants. The initial increases in the cmc and gradual decreases in Γmax values with increasing temperature are attributed to the thermal solubility of the molecules in the bulk and the thermal motion of the adsorbed mo...

Dependence of the Band Bending of the Oxide Semiconductors on pH

Abstract: The dependence of the band bending of the oxide semiconductors on pH have been studied by measuring the flatband potential photopotential, and rest dark potential in the solution without redox species. The rest dark potentials were almost constant with pH, while the flatband potential showed the 60 mV/pH dependence. This indicates that only the band in the space charge layer bends by pH with the 60 mV/pH dependence under the rest dark potential state. The flatband states were held at for , , , and , respectively, under the rest dark potentials The above phenomenon is based on the reaction of the oxide surface state with H+ and/or OH− in the solution. This mechanism is described in detail. The enhancement of the water photolysis on catalyst by the alkaline treatment is well explained by the large band bending in alkaline solution under the rest dark potential state.

Molecular Characterization of the Bacterial Community in Biofilms for Degradation of Poly(3-Hydroxybutyrate- co -3-Hydroxyhexanoate) Films in Seawater

Abstract: Microplastics are fragmented pieces of plastic in marine environments, and have become a serious environmental issue. However, the dynamics of the biodegradation of plastic in marine environments have not yet been elucidated in detail. Polyhydroxyalkanoates (PHAs) are biodegradable polymers that are synthesized by a wide range of microorganisms. One of the PHA derivatives, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) has flexible material properties and a low melting temperature. After an incubation in seawater samples, a significant amount of biofilms were observed on the surfaces of PHBH films, and some PHBH films were mostly or partially degraded. In the biofilms that formed on the surfaces of unbroken PHBH films, the most dominant operational taxonomic units (OTUs) showed high similarity with the genus Glaciecola in the family Alteromonadaceae. On the other hand, the dominant OTUs in the biofilms that formed on the surfaces of broken PHBH films were assigned to the families Rhodobacteraceae, Rhodospirillaceae, and Oceanospirillaceae, and the genus Glaciecola mostly disappeared. The bacterial community in the biofilms on PHBH films was assumed to have dynamically changed according to the progression of degradation. Approximately 50 colonies were isolated from the biofilm samples that formed on the PHBH films and their PHBH-degrading activities were assessed. Two out of three PHBH-degrading isolates showed high similarities to Glaciecola lipolytica and Aestuariibacter halophilus in the family Alteromonadaceae. These results suggest that bacterial strains belonging to the family Alteromonadaceae function as the principal PHBH-degrading bacteria in these biofilms.

Multi-Tev Gamma-Ray Observation from the Crab Nebula Using the Tibet-III Air Shower Array Finely Tuned by the Cosmic-Ray Moon's Shadow

Abstract: The Tibet-III air shower array, consisting of 533 scintillation detectors, has been operating successfully at Yangbajing in Tibet, China since 1999. Using the data set collected by this array from 1999 November through 2005 November, we obtained the energy spectrum of γ-rays from the Crab Nebula, expressed by a power law as (dJ/dE) = (2.09 ± 0.32) × 10–12(E/3 TeV)–2.96±0.14 cm–2 s–1 TeV–1 in the energy range of 1.7-40 TeV. This result is consistent with other independent γ-ray observations by imaging air Cherenkov telescopes. In this paper, we carefully checked and tuned the performance of the Tibet-III array using data on the Moon's shadow in comparison with a detailed Monte Carlo (MC) simulation. The shadow is shifted to the west of the Moon's apparent position as an effect of the geomagnetic field, although the extent of this displacement depends on the primary energy of positively charged cosmic rays. This finding enables us to estimate the systematic error in determining the primary energy from its shower size. This error is estimated to be less than ±12% in our experiment. This energy scale estimation is the first attempt among cosmic ray experiments at ground level. The systematic pointing error is also estimated to be smaller than 0011. The deficit rate and the position of the Moon's shadow are shown to be very stable within a statistical error of ±6% year by year. This guarantees the long-term stability of pointlike source observation with the Tibet-III array. These systematic errors are adequately taken into account in our study of the Crab Nebula.