In the title compound, C12H13N3O5, the conformation of the glycosylic bond is anti [torsion angle = −105.3 (2)°]. The 2′‐deoxyribofuranose moiety adopts an S‐type sugar pucker and the orientation of the exocyclic C—C bond is −sc (trans). 相似文献
A wide variety of [1,2,3]triazolo[5,1-c][1,4]benzoxazines were synthesized through palladium-copper catalyzed reactions of 1-azido-2-(prop-2-ynyloxy)benzene with aryl/vinyl iodides. A plausible reaction mechanism has also been proposed. 相似文献
This paper reports the effect of proton irradiation on the electrical properties of a-As2S3 in the temperature range of 323–418 K and frequency range 0.1–100 kHz. The variation of transport property is studied with proton irradiation dose (1 × 1013 ions/cm2 and 1 × 1015 ions/cm2). It has been observed that proton irradiation changes the dc conductivity (σdc), dc activation energy (ΔEdc) and ac conductivity (σac(ω)). The σdc and σac(ω) increases with dose of proton irradiation. The value of frequency exponent (s) decreases with the temperature and irradiation dose. These results are explained in terms of change in density of defect states in these glasses. 相似文献
A catalytic dihydroxylation reaction on glycals has been developed using a bimetallic oxidizing system to furnish sugar 1,2-diols in a highly stereoselective manner. 相似文献
In this paper, we present a new quadrature demodulation filter to reduce hardware complexity in digital phase rotation beamforming. Due to its low sensitivity to phase delay errors, digital quadrature demodulation is commonly used in ultrasound machines. However, since it requires two lowpass filters for each channel to remove harmonics, the direct use of conventional finite impulse response (FIR) filters in ultrasound machines is computationally expensive and burdensome. In our new method, an efficient multi-stage uniform coefficient (MSUC) filter is utilized to remove harmonic components in phase rotation beamforming. In comparison with the directly implemented FIR (DI-FIR) and the previously-proposed signed-power-of-two FIR (SPOT-FIR) lowpass filters, the proposed MSUC filter reduces the necessary hardware resources by 93.9% and 83.9%, respectively. In simulation, the MSUC filter shows a negligible degradation in image quality. The proposed method resulted in comparable spatial and contrast resolution to the DI-FIR approach in the phantom study. These preliminary results indicate that the proposed quadrature demodulation filtering method could significantly reduce the hardware complexity in phase rotation beamforming while maintaining comparable image quality. 相似文献
Ternary copper indium sulfide (CIS) nanocrystals (NCs) have been synthesized by mixing of binary precursor [CuI(bdpa)2][CuICl2] (1) and/or [CuI(mdpa)2][CuICl2] (2) (where, mdpa and bdpa represent methyl and benzyl ester of 3,5-dimethyl pyrazole-1-dithioic acid, respectively) with InCl3 in a low-temperature solvothermal process. The +1 oxidation state of copper and the atomic ratio Cu to S (1:2) is atomically maintained in the pyrazole-based Cu(I)–S precursor to synthesize phase pure CuInS2. Coordinating solvents like ethylene diamine (EN) and ethylene glycol (EG) have been used in the synthesis without any surfactants. No use of external surfactants in the synthesis of CIS nanoparticles reveals that precursor acts as stabilizing agent. The synthesized nanocrystals were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and energy dispersive X-ray spectroscopy (EDX) studies. The optical property of the nanocrystals shows a pronounced quantum confinement effect in the particles with band gap energy ca. 1.5 eV. The formation mechanism of ternary CIS has been proposed. The pore size distributions of the particles show the average pore diameters 13.1 nm from 1 and 5.3 nm from 2. The calculated values of the specific surface area are 8.123 and 9.577 m2/g for 1 and 2, respectively. The excellent photocatalytic degradation of rose bengal (RB) and rhodamine B (RhB) was demonstrated by the porous CIS nanocrystals.
Graphical abstract Enhanced photocatalytic activity of ternary CuInS2 nanocrystals synthesized from the combination of a binary Cu(I)S precursor and InCl3. Gopinath Mondal, Ananyakumari Santra, Sumanta Jana, Nimai Chand Pramanik, Anup Mondal and Pulakesh Bera
The formulated ABCD matrix formalism is employed to prescribe analytical expression of coupling efficiency of a laser diode to single-mode circular core dispersion-shifted as well as dispersion-flattened fiber via hyperbolic microlens on the tip of the fiber. We assume that field distribution in case of both the source and the fiber is one parameter Gaussian type. For maximum excitation efficiency, it is required that the lens transmitted spot size of the source should match with the spot size of the fiber. Further, as regards the spot size of the fiber, we use Petermann II spot size in order to take care of non Gaussian nature of field of such fibers and to make the estimations more realistic thereby. The investigations are carried out for two different wavelengths 1.3 and 1.5 μm. Our simple method predicts the concerned coupling optics excellently and the necessary evaluations require little computations. This simple but accurate technique is expected to benefit the system designers who work in the field of optical technology. 相似文献
A ceramic SmAlO3 (SAO) sample is synthesized by the solid-state reaction technique. The Rietveld refinement of the X-ray diffraction pattern has been done to find the crystal symmetry of the sample at room temperature. An impedance spectroscopy study of the sample has been performed in the frequency range from 50 Hz to 1 MHz and in the temperature range from 313 K to 573 K. Dielectric relaxation peaks are observed in the imaginary parts of the spectra. The Cole–Cole model is used to analyze the dielectric relaxation mechanism in SAO. The temperature-dependent relaxation times are found to obey the Arrhenius law having an activation energy of 0.29 eV, which indicates that polaron hopping is responsible for conduction or dielectric relaxation in this material. The complex impedance plane plot of the sample indicates the presence of both grain and grain-boundary effects and is analyzed by an electrical equivalent circuit consisting of a resistance and a constant-phase element. The frequency-dependent conductivity spectra follow a double-power law due to the presence of two plateaus. 相似文献
We have developed a microfluidic platform that enables, in one experiment, monitoring of signaling events spanning multiple time-scales and cellular locations through seamless integration of cell culture, stimulation and preparation with downstream analysis. A combination of two single-cell resolution techniques-on-chip multi-color flow cytometry and fluorescence imaging provides multiplexed and orthogonal data on cellular events. Automated, microfluidic operation allows quantitatively- and temporally-precise dosing leading to fine time-resolution and improved reproducibility of measurements. The platform was used to profile the toll-like receptor (TLR4) pathway in macrophages challenged with lipopolysaccharide (LPS)-beginning with TLR4 receptor activation by LPS, through intracellular MAPK signaling, RelA/p65 translocation in real time, to TNF-α cytokine production, all in one small macrophage population (< 5000 cells) while using minute reagent volume (540 nL/condition). The platform is easily adaptable to many cell types including primary cells and provides a generic platform for profiling signaling pathways. 相似文献
An excitation and emission wavelength dependent non-exponential fluorescence decay behaviour of room temperature ionic liquids (RTILs) has been noted. Average fluorescence lifetimes have been found to vary by a factor of three or more. Red emitting dyes dissolved in RTILs are found to follow hitherto unobserved single exponential fluorescence decay behaviour. 相似文献