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301.
302.
The structure factors of Mg2SiO4 glass have been measured using high energy x-ray diffraction up to pressures of 30.2 GPa, and the equation of state measured up to 12.8 GPa. The average Mg-O coordination numbers were extracted from the experimental pair distribution functions assuming two cases (i) there is no change in Si-O coordination number with pressure and (ii) the average Si-O coordination number increases the same as for pure SiO2 glass. Both analyses give similar results and show a gradual increase in the average Mg-O coordination number from 5.0 at ambient pressure to ~ 6.6(6) at 30.2 GPa. There is good qualitative agreement between the experimental structure and equation of state data for the glass compared to several recent molecular dynamics simulations carried out on liquid Mg2SiO4. 相似文献
303.
In this review article we have discussed synthesis, free radical scavenging, enzyme inhibition, anticancer activity, DNA binding of selenoureas and detection of selenium species. We have given the structure and activity relationships of different selenoureas with each other and with their sulfur homologues (thioureas). Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
304.
Atul Kulkarni Rashid Amin Hyeongkeun Kim Byung Hee Hong Sung Ha Park Taesung Kim 《Current Applied Physics》2012,12(3):623-627
We present the photon induced conductivity of 2D DNA lattices with and without graphene and demonstrate the switching current responses controlled by light irradiation. The conductivity in the DNA lattices with protein streptavidin controlled by blue and white lights shows significant enhancement with the addition of graphene. An optical pulse response of a graphene immobilized DNA lattice is encouraging and may lead to various bio-sensing applications such as immunological assays, DNA forensics, and toxin detection. 相似文献
305.
306.
We consider the reconstruction of a heat equation modeling the temperature distribution of a rod from readings at one end only. We assume that the rod, whose length is unknown, is totally buried except for a neighborhood of one of its ends, which is accessible for temperature measurements. We show that, under very mild restrictions, the heat coefficient and the length of the rod can be reconstructed from at most four measurements at one end. 相似文献
307.
Amin AS 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2010,77(5):1054-1058
A highly sensitive, selective and rapid method for the determination μg L(-1) level of Au(III) based on the rapid reaction of Au(III) with 2,3-dichloro-6-(3-carboxy-2-hydroxy-1-naphthylazo)quinoxaline (DCHNAQ) and the solid phase extraction of the colored complex with a reversed phase polymer-based C18 cartridge have been developed. The DCHNAQ reacted with Au(III) to form a violet complex of a molar ratio 3:1 [DCHNAQ to Au(III)] in the presence of 5.0 M of phosphoric acid solution and Triton X-100 medium. This complex was enriched by the solid phase extraction with a polymer-based C18 cartridge. The enrichment factor of 100 was achieved. The molar absorptivity of the complex is 2.73×10(5) l mol(-1) cm(-1) at 633 nm in the measured solution. The system obeys Beer's law in the range of 0.02-1.30 μg ml(-1), whereas the optimum concentration ranges obtained from Ringbom plot was 0.08-1.24 μg ml(-1). The relative standard deviation for ten replicates sample of 0.6 μg ml(-1) level is 1.28%. The detection and quantification limits, are 6.1 and 19.5 ng ml(-1) in the original sample. This method was applied to the determination of gold in water, jewel and ore samples with good results comparing to the GFAAS method. 相似文献
308.
Mahmoud Labib Martin Hedström Magdy Amin Bo Mattiasson 《Analytical and bioanalytical chemistry》2010,397(3):1217-1224
A novel technique for monitoring of low molecular mass analytes using a flow-injection capacitive biosensor is presented.
The method is based on the ability of a small molecular mass analyte to displace a large analyte–carrier conjugate from the
binding sites of an immobilized biorecognition element with weak affinity to both compounds. A model study was performed on
glucose as the small molecular mass analyte. In the absence of glucose, binding of a glucose polymer or a glycoconjugate to
concanavalin A results in a capacitance decrease. Upon introduction of glucose, it displaces a part of the bound glucose polymer
or glycoconjugate leading to a partial restoration of capacitance. Experimental results show that the change in capacitance
depends linearly on glucose concentration within the range from 1.0 × 10−5 to 1.0 × 10−1 M, corresponding to 1.8 μg ml−1 to 18 mg ml−1 in a logarithmic plot, with a detection limit of 1.0 × 10−6 (0.18 μg ml−1) under optimized conditions. In addition, by modifying the molecular mass of the glucose polymer, amount of biorecognition
element, and buffer composition, we were able to tune the analyte-sensing range. The developed technique has the benefits
of expanded dynamic range, high sensitivity, and excellent reusability. 相似文献
309.
Atmospheric plasma spray is a fast and economical process for deposition of yttria-stabilized zirconia (YSZ) electrolyte for
solid oxide fuel cells. YSZ powders have been used to prepare plasma-sprayed thin ceramic films on the metallic substrate
employing plasma spray technology at atmospheric pressure. Alumina doping was employed to improve the structural characteristics
and electrical properties of YSZ. The effect of alumina addition from 1 to 5 wt.% on the properties of plasma-sprayed YSZ
films was investigated. It was found that the gas permeability of the Al-doped YSZ electrolyte layer reached a level of 8.6 × 10−7 cm4 gf−1 s−1, which is a necessary value for the practical operation of solid oxide fuel cells. Alumina doping considerably increased
the ionic conductivity of plasma-sprayed YSZ. The open circuit voltage of the alumina-doped YSZ coating was approximately
equal to the theoretical value for dense YSZ material. 相似文献
310.
The design of the acoustic resonator is critical for the optimization of the sensitivity of laser photoacoustic spectroscopy (LPAS) in trace gas detection applications. In this paper, an LC circuit model is used for the simulation of a 1D acoustic resonator. This acoustic resonator is designed for CO photoacoustic spectroscopy. The effects of the structural parameters, quality factor and resonant frequency on the performance of the device are theoretically analyzed. The role of the buffer volume as an acoustic filter is investigated and optimized dimensions of the buffer volume, to achieve minimum noise transmission coefficient, are calculated. The effects of the ambient temperature, variety of pressure and gas flow velocity on the resonant frequency of photoacoustic resonator and PA signal are simulated. The temperature dependence of the microphone sensitivity is also introduced. 相似文献