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141.
C.-L. Dong J.-W. Chiou H.-M. Tsai H.-W. Fu H.-J. Lin C.T. Chen 《Synchrotron Radiation News》2017,30(2):24-29
Owing to the current energy crisis and extreme changes in the global climate, there is great interest in finding renewable energy resources. Vast progress has been made in the development of new materials related to renewable energy, and their physical/chemical properties can be tailored by nanostructuring and other advanced synthetic approaches. In many important energy systems, such as solar hydrogen systems, the atomic/electronic structures of materials and fundamental interfacial phenomena of systems critically determine the energy conversion efficiency of materials [1, 2]. Without knowledge of the fundamental electronic structures of the materials during conversion reactions, better engineering of the material for practical use is difficult. Understanding and controlling the interfaces in energy generation/conversion/storage materials requires in-situ/operando approaches [3, 4]. The Taiwan Photon Source (TPS) Soft X-ray Spectroscopic beamline provides the capabilities for X-ray absorption (XAS) and X-ray emission (XES) spectroscopies, which can be utilized to investigate unoccupied (conduction-band) and occupied (valence-band) electronic states, respectively. Moreover, resonant inelastic X-ray scattering (RIXS) can be used to study intra-band (including d-d or f-f excitations) and inter-band (charge transfer) transitions [5, 6]. The former provides details about electronic energy splitting in various crystal fields and the latter involves electron transfer between a metal and a ligand, which determines chemical activity [7, 8]. 相似文献
142.
Nitrosylation of the biomimetic reduced- and oxidized-form rubredoxin [Fe(SR)4]2-/1- (R = Ph, Et) in a 1:1 stoichiometry led to the formation of the extremely air- and light-sensitive mononitrosyl tris(thiolate) iron complexes (MNICs) [Fe(NO)(SR)3]- along with byproducts [SR]- or (RS)2. Transformation of [Fe(NO)(SR)3]- into dinitrosyl iron complexes (DNICs) [(RS)2Fe(NO)2]- and Roussin's red ester [Fe2(mu-SR)2(NO)4] occurs rapidly under addition of 1 equiv of NO(g) and [NO]+, respectively. Obviously, the mononitrosyl tris(thiolate) complex [Fe(NO)(SR)3]- acts as an intermediate when the biomimetic oxidized- and reduced-form rubredoxin [Fe(SR)4]2-/1- exposed to NO(g) were modified to form dinitrosyl iron complexes [(RS)2Fe(NO)2]-. Presumably, NO binding to the electron-deficient [Fe(III)(SR)4]- and [Fe(III)(NO)(SR)3]- complexes triggers reductive elimination of dialkyl/diphenyl disulfide, while binding of NO radical to the reduced-form [Fe(II)(SR)4]2- induces the thiolate-ligand elimination. Protonation of [Fe(NO)(SEt)3]- yielding [Fe(NO)(SPh)3]- by adding 3 equiv of thiophenol and transformation of [Fe(NO)(SPh)3]- to [Fe(NO)(SEt)3]- in the presence of 3 equiv of [SEt]-, respectively, demonstrated that complexes [Fe(NO)(SPh)3]- and [Fe(NO)(SEt)3]- are chemically interconvertible. Mononitrosyl tris(thiolate) iron complex [Fe(NO)(SPh)3]- and dinitrosyl iron complex [(EtS)2Fe(NO)2]- were isolated and characterized by X-ray diffraction. The mean NO bond distances of 1.181(7) A (or 1.191(7) A) in complex [(EtS)2Fe(NO)2]- are nearly at the upper end of the 1.178(3)-1.160(6) A for the anionic {Fe(NO)2}9 DNICs, while the mean FeN(O) distances of 1.674(6) A (or 1.679(6) A) exactly fall in the range of 1.695(3)-1.661(4) A for the anionic {Fe(NO)2}9 DNICs. 相似文献
143.
Attempt is to extend the sublayer approach model to capture the combined effects of thermophoresis and turbophoresis on the particle transport in the turbulent boundary flow with thermal gradients. Analytical solution relying on a more detailed picture of the periodic sublayer development in the wall region has been obtained. During the average growth period of viscous sublayer, the physical trend of the modeling parameters has been quantitatively revealed in some extent, and the calculated results of the particle deposition rate for the different ranges of the particle relaxation time are in general agreement with available particle transport data. 相似文献
144.
Computing traffic equilibria with signal settings using TRANSYT model for an area traffic control road system is considered in this paper. Following Wardrop’s first principle, this problem can be formulated as a variational inequality problem. In this paper, we propose a novel algorithm to efficiently solve this equilibrium traffic assignment with global convergence. Numerical calculations are conducted on a grid-size road network. As it shows, the proposed method achieved greater savings in computational overheads than did those conventional methods for solving traffic equilibria when signal settings are particularly taken into account. 相似文献
145.
Curtis P. Rinsland Linda Chiou Emmanuel Mahieu 《Journal of Quantitative Spectroscopy & Radiative Transfer》2009,110(13):1066-1071
The long-term trend of methane (CH4) in the lower stratosphere has been estimated for the 1985-2008 time period by combining spaceborne solar occultation measurements recorded with high spectral resolution Fourier transform spectrometers (FTSs). Volume mixing ratio (VMR) FTS measurements from the ATMOS (atmospheric trace molecule spectroscopy) FTS covering 120-10 hPa (∼16-30 km altitude) at 25°N-35°N latitude from 1985 and 1994 have been combined with Atmospheric Chemistry Experiment (ACE) SCISAT-1 FTS measurements covering the same latitude and pressure range from 2004 to 2008. The CH4 trend was estimated by referencing the VMRs to those measured for the long-lived constituent N2O to account for the dynamic history of the sampled airmasses. The combined measurement set shows that the VMR increase measured by ATMOS has been replaced by a leveling off during the ACE measurement time period. Our conclusion is consistent with both remote sensing and in situ measurements of the CH4 trend obtained over the same time span. 相似文献
146.
Jyh-Liang Wang Yi-Sheng Lai Bi-Shiou Chiou Chen-Chia Chou Trent Gwo-Yann Lee Huai-Yuan Tseng Chueh-Kuei Jan Huang-Chung Cheng 《Applied Physics A: Materials Science & Processing》2008,90(1):129-134
Pulsed laser deposition (PLD) of (Pb,Sr)TiO3 (PSrT) film on Pt/SiO2/Si at low substrate temperatures (Ts), ranging from 300–450 °C, has been investigated. As Ts increases, the films reveal coarsening clusters, improved crystallization of the perovskite phase, distinct capacitance–electric
field (C–E) hysteretic loops and a larger dielectric constant. The 350 °C-deposited film shows strong (100) preferred orientation
and optimum dielectric properties with the dielectric constant of ∼620. The current density increases as the measurement temperature
and the electric field increase. Moreover, PSrT films exhibit a strong negative temperature coefficient of resistance (NTCR)
behavior at temperatures ranging from 100 to 390 °C.
PACS 81.15.Fg; 77.22.Ch; 68.60.Dv 相似文献
147.
148.
[reaction: see text] A lipophilic alpha-keto amide, inhibitor of pancreatic lipase, was synthesized using a lipidic 2-amino alcohol as backbone. The chiral key intermediate 2-(tert-butyloxycarbonylamino)-D-undecen-5-ol was synthesized starting from D-glutamic acid. The inhibitor formed a stable monomolecular film at the air/water interface as shown by a force/area curve. Inhibition studies using the monomolecular film technique with mixed films of 1,2-dicaprin containing variable proportions of the inhibitor showed a 50% decrease in lipase activity at a 0.14 molar fraction. 相似文献
149.
150.
The problem of laminar natural convection flow over a slender frustrum of a cone with constant wall heat flux is treated in this paper. The governing differential equations are solved by a combination of quasilinearization and finite-difference methods. Numerical solutions are obtained for Prandtl numbers from 0.1 to 100 for a range of values of transverse curvature parameter. It is found that the effect of transverse curvature is of great significance in such flows.
Nomenclature A,B,C constants in the transformation, defined in Eq.(14) - f dependent variable, defined in Eq. (7) - g dependent variable, defined in Eq. (7) - ge gravitational acceleration - k heat conductivity - kn -grid - L characteristic length - Nu Nusselt number - Pr Prandtl number - qw wall heat flux - r radial distance from the axis of the cone - RTVC transverse curvature ratio, defined in Eq.(28) - Re Reynolds number - T temperature - u,v velocity components in the x- and y-directions, respectively - x,y rectangular coordinates Greek Letters dimensionless temperature, defined in Eq.(4) - bulk modulus - cone angle - dynamic viscosity - stream function - , transformed independent variables, defined in Eq. (7) - transverse curvature parameter 相似文献
Laminare natürliche Konvektion über einem dünnen, senkrechten Kegelstumpf mit konstantem Wand wär mestrom
Zusammenfassung In dieser Arbeit wird das Problem der laminaren, natürlichen Konvektionsströmung öber einem dünnen Kegelstumpf mit konstantem Wandwärmestrom behandelt. Die maßgeblichen Differentialgleichungen werden mit Hilfe einer Kombination von Quasilinearisierung und Differenzenverfahren gelöst. Numerische Lösungen werden für die Prandtl ' sehen Zahlen zwischen 0. l und 100 innerhalb eines Bereiches von Querkrüm mungswerten erhalten. Es wird gezeigt, daß der Einfluß der Querkrümmung in solchen Strömungen von großer Bedeutung ist.
Nomenclature A,B,C constants in the transformation, defined in Eq.(14) - f dependent variable, defined in Eq. (7) - g dependent variable, defined in Eq. (7) - ge gravitational acceleration - k heat conductivity - kn -grid - L characteristic length - Nu Nusselt number - Pr Prandtl number - qw wall heat flux - r radial distance from the axis of the cone - RTVC transverse curvature ratio, defined in Eq.(28) - Re Reynolds number - T temperature - u,v velocity components in the x- and y-directions, respectively - x,y rectangular coordinates Greek Letters dimensionless temperature, defined in Eq.(4) - bulk modulus - cone angle - dynamic viscosity - stream function - , transformed independent variables, defined in Eq. (7) - transverse curvature parameter 相似文献