23 resultados para Data Coordinating Center
Resumo:
A new algorithm based on the multiparameter neural network is proposed to retrieve wind speed (WS), sea surface temperature (SST), sea surface air temperature, and relative humidity ( RH) simultaneously over the global oceans from Special Sensor Microwave Imager (SSM/I) observations. The retrieved geophysical parameters are used to estimate the surface latent heat flux and sensible heat flux using a bulk method over the global oceans. The neural network is trained and validated with the matchups of SSM/I overpasses and National Data Buoy Center buoys under both clear and cloudy weather conditions. In addition, the data acquired by the 85.5-GHz channels of SSM/I are used as the input variables of the neural network to improve its performance. The root-mean-square (rms) errors between the estimated WS, SST, sea surface air temperature, and RH from SSM/I observations and the buoy measurements are 1.48 m s(-1), 1.54 degrees C, 1.47 degrees C, and 7.85, respectively. The rms errors between the estimated latent and sensible heat fluxes from SSM/I observations and the Xisha Island ( in the South China Sea) measurements are 3.21 and 30.54 W m(-2), whereas those between the SSM/ I estimates and the buoy data are 4.9 and 37.85 W m(-2), respectively. Both of these errors ( those for WS, SST, and sea surface air temperature, in particular) are smaller than those by previous retrieval algorithms of SSM/ I observations over the global oceans. Unlike previous methods, the present algorithm is capable of producing near-real-time estimates of surface latent and sensible heat fluxes for the global oceans from SSM/I data.
Resumo:
C band RADARSAT-2 fully polarimetric (fine quad-polarization mode, HH+VV+HV+VH) synthetic aperture radar (SAR) images are used to validate ocean surface waves measurements using the polarimetric SAR wave retrieval algorithm, without estimating the complex hydrodynamic modulation transfer function, even under large radar incidence angles. The linearly polarized radar backscatter cross sections (RBCS) are first calculated with the copolarization (HH, VV) and cross-polarization (HV, VH) RBCS and the polarization orientation angle. Subsequently, in the azimuth direction, the vertically and linearly polarized RBCS are used to measure the wave slopes. In the range direction, we combine horizontally and vertically polarized RBCS to estimate wave slopes. Taken together, wave slope spectra can be derived using estimated wave slopes in azimuth and range directions. Wave parameters extracted from the resultant wave slope spectra are validated with colocated National Data Buoy Center (NDBC) buoy measurements (wave periods, wavelengths, wave directions, and significant wave heights) and are shown to be in good agreement.
Resumo:
Reactions of freshly prepared M(OH)(2-2x)(CO3)(x) (.) yH(2)O (M = Mn, Zn) and 4,4'-bipyridine (bpy) with succinic acid (H2L) or famaric acid (H2L') in CH3OH-H2O afforded [Mn(H2O)(4)(bpy)]L (.) 4H(2)O, 1, [Mn(H2O)(4)(bpy)]L' (.) 4H(2)O, 2 and [Zn(H2O)(4)(bpy)]L (.) 4H(2)O, 3. The three coordination polymers are isostructural and consist of (1)(infinity)[M(H2O)(4)(bpy)(2/2)](2+) cationic chains, crystal H2O molecules and dicarboxylate anions (succinate or fumarate anions). Within the chains, the metal atoms are each octahedrally coordinated by four aqua oxygen atoms and two pyridyl nitrogen atoms from two 4,4'-bipyridine ligands. The crystal H2O molecules are hydrogen bonded to dicarboxylate anions to form ribbon-like anionic chains. The cationic and anionic chains are interconnected via hyqrogen bonds to generate a 3D network. Crystal data: 1 triclinic, P (1) over bar, a = 7.235(1), b = 7.749(2), c = 10.020(2) Angstrom, alpha = 79.95(3), beta = 88.79(3), gamma = 71.39(3)degrees, V = 523.9(2) Angstrom(3) and D-cal = 1.494 g cm(-3) for Z = 1; 2 triclinic, P (1) over bar, a = 7.127(1), b = 7.800(2), c = 9.945(2) Angstrom, alpha = 80.26(3), beta = 87.86(3), gamma = 72.69(3)degrees, V = 520.2(2) Angstrom(3) and D-cal = 1.498 g cm(-3) for Z = 1; 3 triclinic, P (1) over bar, a = 7.189(1), b = 7.764(2), c = 9.843(2) Angstrom, alpha = 79.16(3), beta = 87.80(3), gamma = 71.29(3)degrees, V = 510.9(2) Angstrom(3) and D-cal = 1.559 g cm(-3) for Z = 1.
Resumo:
A chain coordination polymer with the chemical formula {[Cu4L2(H2O)] (.) H2O)(n), has been synthesized by the assembly reaction of K(2)CuL(.)1.5H(2)O and Cu(OAC)(2)(H2O)-H-. with a 1:1 mole ratio in methanol., where H4L=2-hydroxy-3-[(E)-({2-[(2-hydroxybenzoyl)imino]ethyl I imino)methyl] benzoic acid, OAC(-) = CH3COO-. The crystal structure was determined by single-crystal X-ray diffraction analysis, the compound has chain molecular structure formed by dissymmetrical tetranuclear units. The magnetic measurements showed that Cu-Cu of the complex exhibit antiferromagnetic interactions, and satisfactory fittings to the observed magnetic susceptibility data were obtained by assuming a binuclear system, and further using molecular field approximation to deal with magnetic exchange interactions between binuclear systems.
Resumo:
An organic-inorganic hybrid molybdenum phosphate, Na-2[{Mn(phen)(2)(H2O)} {Mn(phen)(2)}(3){(MnMo12O24)-O-v (HPO4)(6)(PO4)(2) (OH)(6)}] . 4H(2)O (phen=1,10-phenanthroline), involving molybdenum present in V oxidation state and covalently bonded transition metal coordination complexes, has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Deep brown-red crystals are formed in the triclinic system, space group P (1) over bar, a=16.581(l)Angstrom, b=18.354(1)Angstrom, c=24.485(2)Angstrom, alpha=80.589(l)degrees, beta=71.279(1)degrees, gamma=67.084(1)degrees, V=6493.8(8)Angstrom(3), Z=2, lambda(MoKalpha)=0.71073Angstrom (R(F)=0.0686 for 29,053 reflections). Data were collected on a Bruker Smart Apex CCD diffractometer at 293 K in the range of 1.76 < theta < 28.06degrees using omega-2theta scans technique. The structure of the title compound may be considered to be based on {Mo6O12(HPO4)(3)(PO4)(OH)(3)} units bonded together with {Mn(phen)(2)} subunits into a two-dimensional network. Two types of tunnels are observed in the solid of the title compound.
Resumo:
The hydrothermal reactions of vanadium oxide starting materials with divalent transition metal cations in the presence of nitrogen donor chelating ligands yield the bimetallic cluster complexes with the formulae [{Cd(phen(2))(2)V4O12].5H(2)O (1) and [Ni(phen)(3)](2)[V4O12] . 17.5H(2)O (2). Crystal data: C48H52Cd2N8O22V4 (1), triclinic. P (1) over bar, a = 10.3366(10), b = 11.320(3), c = 13.268(3) Angstrom, alpha = 103.888(17)degrees, beta = 92.256(15)degrees, gamma = 107.444(14)degrees, Z = 1; C72H131N12Ni2O29.5V4 (2), triclinic. P (1) over bar, a = 12.305(3), b = 13.172(6), c = 15.133(4), alpha = 79.05(3)degrees, beta = 76.09(2)degrees, gamma = 74.66(3)degrees, Z = 1. Data were collected on a Siemens P4 four-circle diffractometer at 293 K in the range 1.59degrees < theta < 26.02degrees and 2.01degrees < 0 < 25.01degrees using the omega-scan technique, respectively. The structure of 1 consists of a [V4O12](4-) cluster covalently attached to two {Cd(phen)(2)}(2+) fragments, in which the [V4O12](4-) cluster adopts a chair-like configuration. In the structure of 2, the [V4O12](4-) cluster is isolated. And the complex formed a layer structure via hydrogen bonds between the V4O12](4-) unit and crystallization water molecules.
Resumo:
Two novel compounds, [Co(4,4'-bipy)(H2O)(4)](4-abS)(2).H2O (1) and [Mn(4,4'-bipy)(H2O)(4)](4-abs)(2).2H(2)O (2) (4,4'-bipy = 4,4'-bipyridine; 4-abs = 4-aminobenzenesulfonate), have been synthesized in aqueous solution and characterized by single-crystal X-ray diffraction, elemental analyses, UV-vis and IR spectra, and TG analysis. X-ray structural analysis revealed that 1 and 2 both possess unusual hydrogen-bonded three-dimensional (3-D) networks encapsulating one-dimensional (1-D) covalently bonded infinite [M(4,4'-bipy)(H2O)(4)](2+) (M = Co, Mn) chains. The 4-abs anions in 1 form 1-D zigzag chains through hydrogen bonds. These chains are further extended through crystallization water molecules into 3-D hydrogen-bonded networks with 1-D channels, in which the [Co(4,4'-bipy)(H2O)(4)](2+) linear covalently bonded chains are located. Crystal data for 1: C22H30CoN4O11S2, monoclinic P2(1), a = 11.380(2) Angstrom, b = 8.0274(16) Angstrom, c = 15.670(3) Angstrom, alpha = gamma = 90degrees, beta = 92.82(3)degrees, Z = 2. Compound 2 contains interesting two-dimensional (2-D) honeycomb-like networks formed by 4-abs anions and lattice water molecules via hydrogen bonding, which are extended through other crystallization water molecules into three dimensions with 1-D hexagonal channels. The [Mn(4,4'-bipy)(H2O)(4)](2+) linear covalent chains exist in these channels. Crystal data for 2: C22H32WN4O12S2, monoclinic P2(1)/c, a = 15.0833(14) Angstrom, b = 8.2887(4) Angstrom, c = 23.2228(15) Angstrom, alpha = gamma = 90degrees, beta = 95.186(3)degrees, Z = 4.
Resumo:
In this paper, we will report the preparation of a mixed-valence polyoxometalate compound (Bu4N)(4)[PMo12O40].2DMF.H2O (TBA = tetrabutylammonium; DMF = N,N-dimethyl formamide). The title compound has been photochemically synthesized and characterized by using elemental analysis, IR, solid diffusion reflectance electronic spectra, ESR spectra, XPS, CV and X-ray single-crystal analysis. The crystal lographic data are as follows: monoclinic, P2(1)/c, a = 14.124(3), b = 17.481(4), c = 22.744(5) Angstrom, beta = 101.66(3)degrees, V = 5500(2) Angstrom(3), C70H160Mo12N6O43P, M-r = 2956.29, Z = 2, D-c = 1.785 g/cm(3), F(000) = 2970 and mu(MoKalpha) = 1.412 mm(-1). The structure has been refined to R = 0.0638 and wR = 0.1975 by full-matrix least-squares methods. The title compound is composed of four tetrabutylammonium cations, one [(PMoMo11O40)-Mo-V](4-) heteropoly anion, two N,N-dimethyl formamide and one H2O molecule.
Resumo:
A new compound, [Ni(en)(3)](2)[Ni(en)(2)(H2O)(2)][As6V15O42] . 4H(2)O, was first prepared by hydrothermal synthesis and characterized by elemental analysis, IR, TGA-DSC, ESR and single crystal X-ray diffraction. Crystal data: monoclinic, space group C-c, a = 1. 523 6(3) nm, b = 2. 051 8(4) nm, c = 2.395 9(5) nm, beta = 97. 41(3)degrees, V = 7.427(3) nm(3), Z = 4, R = 0. 057 0, wR(2) = 0.135 7. The polyanion consists of six AsO3 pyramids and fifteen VO5 pyramids. Counterions are complex ions with octahedral structure, which consist of NH2CH2CH2NH2 and Ni2+.
Resumo:
A novel manganese phosphomolybdate, [H3N(CH2)(4)NH3](H3O)(2){[Mn(phen)(2)](4)[(MnMovO30)-O-12(HPO4)(6)(H2PO4)(2)]} . 4H(2)O 1, has been hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction. The crystal data: triclinic, P (1) over bar, a = 14.172(7) Angstrom, b = 16.547(2) Angstrom, c = 16.679(3) Angstrom, alpha = 62.881(12)degrees, beta = 73.83(3)degrees, gamma = 88.81(3)degrees. X-ray crystallography shows that the [Mn(phen)(2)] fragments are covalently bonded to the [Mn(Mo6P4)(2)] dimers leading to a one-dimensional chain with rectangular cavities occupied by tetramethylene-diamine cations and water molecules. (C) 2002 Elsevier Science B.V. All rights reserved.
Resumo:
A novel compound [Ni(phen)(3)](2)[(SiMo10V1/2O40)-O-V((VO)-O-IV)(2)] . 2H(2)O has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. The compound crystallizes in the triclinic, system, space group P-1, a = 12.378(4) Angstrom, b = 14.148(5) Angstrom, c = 14.316(2) Angstrom, alpha = 105.91(2)degrees, beta = 95.31(2)degrees, gamma = 96.89(3)degrees, V = 2373.0(12) Angstrom(3), Z = 1, (lambdaMo(Kalpha)) = 0.71073 Angstrom, R1 (wR2) = 0.0869(0.2174). Data were collected on a Siemens P4 four-circle diffractometer at 293 K in the range of 1.51 < theta < 22.50degrees using the omega-scan technique. Empirical absorption correction (psi scan) was applied. The structure was solved by the direct method and refined by the Full-matrix least-squares on F-2 using the SHELXL-97 software. X-ray crystallographic study showed that the title compound contained a bi-capped alpha-Kegin-type [(SiMo10V2O40)-O-IV((VO)-O-IV)(2)](4-) polyoxoanion.
Resumo:
A novel compound [Cu(en)(2)](4)[(SiMo8V4O40)-O-v(V-IV O)(2)] [MoO4](2) . 5H(2)O has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Black crystals crystallize in the tetragonal. system, space group 14/m, a = b = 14.019(2) Angstrom, c = 20.341(4) Angstrom, V = 3997.9(11) Angstrom(3), Z = 2, lambda(MoKalpha) = 0.71073 Angstrom (R(F) = 0.0443 for 1819 reflections). Data were collected on a Siemens P4 four-circle diffractometer at 293 K in the range of 1.76 < theta < 24.98degrees using the omega-scan technique. The structure was solved by the direct method and refined by the full-matrix least squares on F-2 method using the SHELXL-97 software. X-ray crystallographic study showed that the title compound contained a bicapped alpha-Keggin fragment [SiMo8 (V4O40)-O-v((VO)-O-IV)(2)](4-) polyoxoanion.
Resumo:
[NH3CH2CH2CH2NH2][NH3CH2CH2CH2NH3](2)[(As2AsMo8V4O40)-As-III-Mo-V-O-IV].3H(2)O was hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction. Crystal data: monoclinic, C2/c, a = 45.375(9) Angstrom, b = 11.774(2) Angstrom, c = 23.438(5) Angstrom, beta = 96.62(3)degrees. X-ray crystallographic study showed that the crystal structure was constructed by bicapped alpha-Keggin fragments [(As2AsMo8V4O40)-As-III-Mo-V-O-IV](5-) polyoxoanion. The title compound had a high catalytic activity for the oxidation of benzaldehyde to benzoic acid using H2O2 as oxidant in a liquid-solid biphase system.
Resumo:
The title compound, [C12H24O6][H3PMo12O40]. 22H(2)O, was synthesized by the self-assembly of 18-crown-6 (abbreviated as C12H24O6 or 18C6) and H3PMo12O40 in the mixed solvent of CH3OH and CH3CN, and was characterized by IR, H-1 NMR and Xray diffraction for the first time. Crystal data: Triclinic, P (1) over bar, a = 13.428(3) Angstrom, b = 13.557(3)A, c = 14.642(3) Angstrom, a = 105.39(3)degrees, beta = 90.06(3)degrees, gamma = 119.56(5)degrees, V = 2207.5(8) Angstrom(3), Z = 1, R1 = 0.0719, wR2 = 0.1990. It has a disordered alpha-Keggin PMo12O403- anion, which contains the strong alternating short (mean 1.844 Angstrom) and long (mean 1.958 Angstrom) Mo-O-Mo bonds. In the unit cell, crown ethers and molybdophosphates are alternatively arranged in good order along c-axis. An oxonium ion is located at the center of a crown ether molecule., Oxonium ion interacts with 18C6 by the means of hydrogen bonds (mean 2.7771 Angstrom), which are electrostatic or resonant. The observations show the existence of [H3O(C12H24O6)](+) (C) 2000 Elsevier Science B.V. All rights reserved.
Resumo:
The title compound, [H3PMo12O40][CO(NH2)(2)](3). 5H(2)O, was synthesized and characterized by IR, C-13 NMR and X-ray diffraction. This is the first example of a urea-heteropoly acid species. Crystal data: monoclinic, C2/c, a = 17.790(4) Angstrom, b = 17.158(3) Angstrom, e = 25.512(5) Angstrom, beta = 100.65(3)degrees, V = 8514(3) Angstrom (3), Z = 6, R-1 = 0.0437, wR2 = 0. 1092. In the unit cell, the urea molecules occupy cavities in the polyoxometalate lattice ordered along b-axis. Water molecules occupy the space left by polyoxometalates, and urea. Polyoxometalate O atoms, the N atoms of urea and O atoms of water molecules are involved in hydrogen bonding. (C) 2001 Elsevier Science B.V. All rights reserved.