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111.
112.
High-resolution absorption lineshapes of the R(7) and P(2) transitions in the first overtone (v = 0-2) band of H(79)Br have been recorded at room temperature using a pair of distributed feedback diode lasers operating near 1.95 and 2.00 μm, respectively. Spectral line intensities and self-broadening coefficients were determined by fitting the measured spectra (for various pressures P = 10-100 Torr) with Voigt profiles and compared with values in the literature. Measured line intensities for the P(2) and R(7) transitions are approximately 11 and 16% higher than those listed in the HITRAN database, respectively. The measured self-broadening coefficient of the P(2) transition is approximately 14% lower than the value listed in HITRAN. Measurements of the P(2) lineshapes at low pressure (100 mTorr) were modeled with eight-line Gaussian profiles based on ground state (v = 0) hyperfine constants to include the effects of nuclear electric quadrupole interactions. Copyright 2000 Academic Press. 相似文献
113.
An approach to estimating and extrapolating model error based on inverse problem methods:towards accurate numerical weather prediction 总被引:1,自引:0,他引:1 下载免费PDF全文
Model error is one of the key factors restricting the accuracy of numerical weather prediction(NWP). Considering the continuous evolution of the atmosphere, the observed data(ignoring the measurement error) can be viewed as a series of solutions of an accurate model governing the actual atmosphere. Model error is represented as an unknown term in the accurate model, thus NWP can be considered as an inverse problem to uncover the unknown error term. The inverse problem models can absorb long periods of observed data to generate model error correction procedures. They thus resolve the deficiency and faultiness of the NWP schemes employing only the initial-time data. In this study we construct two inverse problem models to estimate and extrapolate the time-varying and spatial-varying model errors in both the historical and forecast periods by using recent observations and analogue phenomena of the atmosphere. Numerical experiment on Burgers’ equation has illustrated the substantial forecast improvement using inverse problem algorithms. The proposed inverse problem methods of suppressing NWP errors will be useful in future high accuracy applications of NWP. 相似文献
114.
Ruey-Shi Tsai Hsiu-Yu Chou Jiang-Wen You Da-Kong Lee Ya-Fen Lin Hsiue-Hsyan Wang 《Journal of Macromolecular Science: Physics》2014,53(3):452-461
Injection molded specimens of a poly(4-methylpentene) (TPX) were annealed at temperatures between 140 and 220°C for times up to 500 min in air, and the annealed TPX specimens were characterized by the differential scanning calorimeter, UV–visible spectrometry, FT-IR, and X-ray diffraction. The annealing of the TPX specimens at 140–180°C for 50 min showed little effect on their thermal properties. However, the thermal properties were significantly affected by annealing at 200–220°C, and the change was dependent on the annealing time. Besides the annealing effect, the thermal properties were also affected by oxidative degradation. Severe oxidative degradation can destroy the crystalline structure and thus decreases the crystallinity. The oxidative degradation phenomenon of the TPX specimens during annealing can be simulated by isothermal scanning of the weight loss in air by thermal gravimetric analysis. 相似文献
115.
Liao JH Chen CT Chou HC Cheng CC Chou PT Fang JM Slanina Z Chow TJ 《Organic letters》2002,4(18):3107-3110
[structure: see text] A push-pull conjugated molecule, 2,7-bis(1H-pyrrol-2-yl)ethynyl-1,8-naphthyridine (BPN), has been designed to bind selectively with octyl glucopyranoside (OGU). The BPN/OGU quadruple hydrogen-bonding complex adopts a rigid BPN conformation in which the proton donor (d) and acceptor (a) relays (daad) are resonantly conjugated through the ethynyl bridge, inducing pi-electron delocalization, i.e., a charge transfer effect. The excellent photophysical properties make BPN a highly sensitive probe for monitoring glucopyranoside to a detection limit of approximately 100 pM. 相似文献
116.
We report difference frequency generation-based wavelength converters with multiple phase-matching wavelengths that use engineered quasi-phase-matching structures in LiNbO(3) waveguides. Multiple-channel wavelength conversion is demonstrated within the 1.5-mum band and between the 1.3- and 1.5-mum bands. With simultaneous use of M pump wavelengths, these devices can also be used to perform wavelength broadcasting, in which each of N input signals is converted into M output wavelengths. 相似文献
117.
118.
A simple and rapid polyamide chromatographic method for the detection of 12 kinds of preservatives and 3 kinds of artificial sweeteners were reported. The results indicated that the method was good in sensitivity, separability and reproducibility. 相似文献
119.
A newly developed self-consistent-field molecular orbital theory is described and tested. The intermediate neglect of differential overlap (INDO) approximation is used, and all interaction integrals are differentiated according to their dependence upon 2s and 2p AO's. The bonding parameter βl is reformulated so that the model is calibrated to only one specific molecular property, namely, the ionization energy of Hi. We expect that this model will not be biased toward any special families of molecules. 相似文献
120.
Nafion membranes are used as semisolid electrolytes in methanol and hydrogen fuel cells. The ion conduction takes place through those hydrophilic channels in the Nafion that can provide continuous pathways through the membrane. There is as yet limited information about the density, the size, and the shape of these channels. We have developed two electrochemical methods of visualizing the pore structure which involve the creation of metal lithographs using the membrane pores as templates. In the experiments, the membrane is supported on a flat solid surface on one side, and is in contact with an electrolyte on the other side. Using hydrogen-terminated n-doped Si(111), we deposited gold from an electrolyte containing a gold salt. The Au ions traverse the membrane through the pores, reach the silicon surface, and are spontaneously reduced. A metallic Au deposit is formed on the silicon surface, at the base of the hydrophilic channel. The Au deposits are imaged after the membrane is dissolved. Another method involves supporting the membrane on a Pt surface and depositing silver wires through the hydrophilic channels of the membrane. The scanning electron microscope pictures of these wires provide an image of the size and the shape of the hydrophilic channels. 相似文献