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71.
The surface potential of Zn1−xMgxO/ZnO heterostructure grown by radical source molecular beam epitaxy was measured by Kelvin force microscopy (KFM). A clear correlation was observed between the topographic image and the surface potential of Zn0.56Mg0.44O/ZnO heterostructure. The potential area around the surface pits was about 60 mV lower than that of the surrounding region, which suggests the effects of the pits on the electrical properties of the potential layer. In order to guarantee the accuracy of measurement, the probe shape was analyzed by probe characterizer and using Au thin films as a potential standard. 相似文献
72.
The Cl atom-initiated oxidation of CH2Cl2 and CH3Cl was studied using the FTIR method in the photolysis of mixtures typically containing Cl2 and the chlorinated methanes at 1 torr each in 700 torr air. The results obtained from product analysis were in general agreement with those reported by Sanhueza and Heicklen. The relative rate constant for the Cl atom reactions of CH2Cl2 and CH3Cl was determined to be k(Cl +CH3Cl)/k(Cl + CH2Cl2) = 1.31 ± 0.14 (2σ) at 298 ± 2 K. 相似文献
73.
Product studies were made using the Fourier transform infrared method in the uv (300–400-nm) photolysis of mixtures containing CH3SCH3, C2H5ONO, and NO in ppm concentrations in 700 torr of O2–N2 diluent. Methyl thionitrite, CH3SNO, arising from the reaction CH3S + NO, was detected as an intermediate product. In addition, the yields of the major sulfur-containing products SO2 and CH3SO3H coincided with those of the oxidation of the CH3S radicals generated directly by the photodissociation of CH3SNO. The formation of CH3S in the HO-initiated oxidation of CH3SCH3 in the presence of NO suggests a reaction scheme involving the H-abstraction reaction HO + CH3SCH3 → CH3SCH2 + H2O as the primary step. 相似文献
74.
Masatoshi Ikeuchi Hiroshi Kobayashi Hideo Sawami Hiroshi Niki 《Journal of Computational and Applied Mathematics》1979,5(4):247-258
The spectral radius of the Jacobi iteration matrix plays an important role to estimate the optimum relaxation factor, when the successive overrelaxation (SOR) method is used for solving a linear system. The specific systems are finite difference forms of the Laplace equation satisfied on a rectanglar region with two different media. Though the potential function for the inhomogeneous closed region is continuous, the first order derivative is not continuous. So this requires internal boundary conditions or interface conditions. In this paper, the spectral radius of the Jacobi iteration matrix for the inhomogeneous rectangular region is formulated and the approximation for the explicit formula, suitable for the computation of the spectral radius, is deduced. It is also found by the proposed formula that the spectral radius and the optimum relaxation factor rigorously depend on the inhomogeneity or the internal boundary conditions in the closed region, and especially vary with the position of the internal boundary. These findings are also confirmed by the numerical results of the power method.The stationary iterative method using the proposed formula for calculating estimates of the spectral radius of the Jacobi iteration matrix is compared with Carré's method, Kulstrud's method and the stationary iterative method using Frankel's theoretical formula, all for the case of some numerical models with two different media. According to the results our stationary iterative method gives the best results ffor the estimate of the spectral radius of the Jacobi iteration matrix, for the required number of iterations to calculate solutions, and for the accuracy of the solutions.As a numerical example the microstrip transmission line is taken, the propating mode of which can be approximated by a TEM mode. The cross section includes inhomogeneous media and a strip conductor. Upper and lower bounds of the spectral radius of the Jacobi iteration matrix are estimated. Our method using these estimates is also compared with the other methods. The upper bound of the spectral radius of the Jacobi iteration matrix for more general closed regions with two different media might be given by the proposed formula. 相似文献
75.
Y. X. Watanabe S. Arai Y. Arakaki Y. Fuchi Y. Hirayama N. Imai H. Ishiyama S. C. Jeong H. Kawakami H. Miyatake K. Niki T. Nomura M. Okada M. Oyaizu M. H. Tanaka M. Tomizawa N. Yoshikawa S. Abe S. Hanashima T. Hashimoto S. Ichikawa H. Ikezoe T. Ishii N. Ishizaki H. Kabumoto I. Katayama M. Koizumi M. Matsuda S. Mitsuoka T. Nakanoya K. Nishio I. Ohuchi A. Osa T. K. Sato S. Takeuchi H. Tayama Y. Tsukihashi 《The European physical journal. Special topics》2007,150(1):259-262
An ISOL-based radioactive nuclear beam (RNB) facility,
Tokai Radioactive Ion Accelerator Complex (TRIAC),
has been jointly developed
by High Energy Accelerator Research Organization (KEK)
and Japan Atomic Energy Agency (JAEA).
The facility started to supply RNBs for experiments in 2005
and RNBs including fission fragments with energies up to 1.1MeV/A
are available in the present.
Several experimental studies were performed successfully
using 8Li beams
with various energies. 相似文献
76.
81Br NQR measurements of the mixed-valence compound (NH4)4SbIII SbVBr12, which has SbVBr6 ? and SbIIIBr6 3? octahedra in different oxidation states in the tetragonal pseudo-K2PtCl6 structure, were carried out by pulse method in the temperature range between 80 and 300 K. The phase transition temperature of T c = 212 K was redetermined. The T 1 values are quite different between SbVBr6 ? and SbIIIBr6 3? octahedra. For all resonance lines T 1 minima were observed at T c. The T 1 behavior at T c was explained by a softening of the rotary lattice mode around a principal axis of each octahedron along the c axis of the crystal. The distinctive feature in the temperature dependence of both 81Br NQR frequencies and T 1 values for each anion indicates that the static rotation may occur for SbVBr6 ? but not for SbIIIBr6 3? at T c in the low temperature phase. 相似文献
77.
78.
Niki C. Maragou George Balayiannis Evangelos Karanasios Emilia Markellou Konstantinos Liapis 《Molecules (Basel, Switzerland)》2021,26(22)
Sludge generated after washing of fruits and vegetables during agro-food processes is a complex matrix and selective methods for the identification and quantification of pesticides’ residues are necessary in order to achieve a sustainable and effective management of the total sewage. The present work describes the development and validation of a reliable, simple and fast analytical method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the determination of 47 pesticides of different chemical classes, including organosphosphates, pyrethroids, neonicotinoids, triazoles and others, in sludge samples after QuEChERS sample preparation. The necessity of the individual steps of QuEChERS was investigated and the LC-ESI-MS/MS conditions were optimized to achieve maximum sensitivity of the target analytes. The method limits of detection (LODs) ranged between 0.0005 mg/kg (imidacloprid) and 0.05 mg/kg (beta cyfluthrin). The recoveries ranged between 71–120% and the repeatability of the method was ≤25% expressed as relative standard deviation. The method was applied to sludge samples generated after washing of fruits in an agro-fruit-packaging unit in Greece. The results showed the presence of 37 pesticides’ active substances with concentrations ranging from low ppbs, such as fludioxinil (5 μg/kg) up to low ppms such as beta cyfluthrin (3.5 mg/kg) and with their sum concentration reaching up to 19 mg/kg. 相似文献
79.
Khumaeni A Lie ZS Niki H Kurniawan KH Tjoeng E Lee YI Kurihara K Deguchi Y Kagawa K 《Analytical and bioanalytical chemistry》2011,400(10):3279-3287
A novel method for the direct and sensitive analysis of powder samples has been developed by utilizing the characteristics
of a transversely excited atmospheric (TEA) CO2 laser. In this study, a powder sample was placed in a container and covered by a metal mesh; the metal mesh functions to
control the blowing-off of the powder. The container was then perpendicularly attached on a metal surface. When a TEA CO2 laser (1.5 J, 200 ns) was focused on the metal surface, a large hemispherical gas plasma (radius of around 8 mm) with long
emission lifetime (several tens of microseconds) was produced without ablating the metal surface. The high-speed expansion
force of the gas plasma samples the powder covered by the metal mesh and fine powder particles are sent into the gas plasma
region to be dissociated and excited. Sensitive semi-quantitative analysis was made on organic powder samples such as powdered
rice, starch, seaweed (agar), and supplements. The detection limit of heavy metals of Cr in powdered mineral supplement was
approximately 0.55 mg/kg. 相似文献
80.
Niki Prastomo Kouji Kimata Yusuke Daiko Hiroyuki Muto Toshihiro Kogure Mototsugu Sakai Atsunori Matsuda 《Journal of Sol-Gel Science and Technology》2010,56(3):345-352
SiO2·TiO2 coatings were prepared by a sol–gel route. The effect of the external fields including mechanical vibration and electric
charge applied during hot-water treatment on titania precipitation at the surface of the coatings was investigated. The shape
of the resulting precipitates tended to elongate by applying vibration in a parallel or perpendicular direction, or by applying
an electric charge. The organization of titania nanocrystallites possibly occurs because of the concentration gradient of
dissolved titania species generated by the external fields during the hot-water treatment. A maximum aspect ratio of 38.1
was achieved for the precipitate prepared by hot-water treatment performed under parallel vibration for 5 h. The shape of
the resulting precipitates was also influenced by the content of TiO2 in the SiO2·TiO2 coating, with a smaller proportion of TiO2 increasing the aspect ratio of the resulting precipitate. 相似文献