The discovery of superconductors whose critical temperatures are above liquid nitrogen temperature has prompted considerable interest in hybrid superconducting-semiconducting electronics applications. The authors review the efforts to hybridize these technologies. Some of these efforts have already been demonstrated on a laboratory scale; others are at present just theoretical proposals. Hybridization is possible on the system, circuit, and device levels. The authors review studies of the applications of superconductors for interconnecting semiconductor systems and combining semiconductor and superconductor devices to enhance the performance of both digital and analog systems. Novel circuit combinations of superconducting and semiconducting devices are mentioned, as are proposals to combine these materials on the device level. It is noted that the use of hybrid combinations may permit some electronic functions to be performed better than either technology could perform separately 相似文献
Wurtzite GaN nanowires and nanoribbons were produced directly from Ga metal by an Au catalyst assisted thermal evaporation process in a flowing ammonia atmosphere. We have investigated the effect of different experimental parameters on the morphology of the nanoforms. The diameters of the nanowires were varied between 20 and 40 nm while the widths of the nanoribbons were within 100-250 nm. Microstructural studies by TEM reveals the role of vapor-liquid-solid process in the nucleation of GaN nanoforms. The evolution of the ribbon like morphology was attributed to the vapor-solid process. Photoluminescence study showed UV-blue emission from the GaN nanostructures. Field emission studies indicated the possibility of these materials to be used as the cathode materials in field emission based devices. 相似文献
A non‐isothermal model based on linear driving force approximation for a system like CO2 – moisture – N2 – molecular sieve, 5A predicted the experimental results satisfactorily for simultaneous adsorption of CO2 and moisture in a fixed bed. Moisture being the strongly adsorbed component forces carbon dioxide (weakly adsorbed component) to be rolled up. The thermophysical and transport properties of moisture mainly governs the dynamics of the process, control or manipulation of which could give better separation by adsorption of one component from the other lying together in a stream. The major parameters are inlet adsorbate concentration, particle Reynolds number, bed diameter to bed length ratio, Schmidt number, Equilibrium Distribution coefficient, Sherwood number, and Kutateladze number. 相似文献
Intense visible emissions from dysprosium(Dy3+) ions doped glasses became prospective for diverse technological applications. In this paper, physical, optical and structural properties of magnesium borate glasses doped with varied concentrations of Dy_2 O_3 were examined. Such glasses were synthesised by melt quenching method and characterized at room temperature using several analytical techniques.Luminescence and absorption spectra(in the visible region) of as-quenched samples were used to evaluate the physical and optical properties. XRD pattern confims the amorphous state of as-quenched samples. The Fourier transform infrared(FTIR) spectra of glasses reveal various bonding vibrations assigned to different functional groups. UV-vis-NIR spectra disclose eight absorption bands accompanied by a band for hypersensitive transition positioned at 1260 nm(~6 H_(15/2)→~6 F_(11/2)). The values of direct and indirect optical energy band gap of the studied glasses are decreased with the increase of Dy~(3+) ion contents. The photoluminescence spectra of all glasses under the excitation of 380 nm display two prominent emission bands centred at 497 nm(~4 F_(9/2)→~6 H_(15/2), blue) and 587 nm(~4 F_(9/2) →~6 H_(13/2), green).The achieved intense luminescence from the proposed glass composition may be beneficial for solidstate laser applications. 相似文献
This article presents a novel binary collective animal behavior algorithm to solve the problem of optimal allotment of distributed generation sets and shunt capacitors in radial distribution systems. Simultaneous sizing and placement of distributed generation units and shunt capacitors in distribution systems is a very complex optimization task, because it is a problem of combinatorial analysis with mixed-integer and binary variables and hard restrictions. With the objective of optimal allotment of shunt capacitor banks and distributed generations, a binary collective animal behavior algorithm optimizes the total line loss, or the total voltage deviation separately in a distribution system, by optimally and simultaneously allocating capacitor banks and distributed generations of optimal ratings, considering the topology of a radial distribution network. The binary collective animal behavior algorithm is applied on various balanced IEEE radial distribution networks. The results are compared to those of a conventional binary particle swarm optimization algorithm to establish the optimization superiority of binary collective animal behavior algorithm. 相似文献
Vessel extraction from retinal fundus images is essential for the diagnosis of different opthalmologic diseases like glaucoma, diabetic retinopathy and hypertension. It is a challenging task due to presence of several noises embedded with thin vessels. In this article, we have proposed an improved vessel extraction scheme from retinal fundus images. First, mathematical morphological operation is performed on each planes of the RGB image to remove the vessels for obtaining noise in the image. Next, the original RGB and vessel removed RGB image are transformed into negative gray scale image. These negative gray scale images are subtracted and finally binarized (BW1) by leveling the image. It still contains some granular noise which is removed based on the area of connected component. Further, previously detected vessels are replaced in the gray-scale image with mean value of the gray-scale image and then the gray-scale image is enhanced to obtain the thin vessels. Next, the enhanced image is binarized and thin vessels are obtained (BW2). Finally, the thin vessel image (BW2) is merged with the previously obtained binary image (BW1) and finally we obtain the vessel extracted image. To analyze the performance of our proposed method we have experimented on publicly available DRIVE dataset. We have observed that our algorithm have provides satisfactory performance with the sensitivity, specificity and accuracy of 0.7260, 0.9802 and 0.9563 respectively which is better than the most of the recent works.
Electrical impedance spectroscopy (EIS) is an electrical impedance technique to characterize the fruits and vegetables in terms of their frequency dependent bioimpedance profile. Standalone, portable, and low‐cost instrumentation is always preferred for conducting EIS procedures. This article reports the studies on the design and development of a Microcontroller based portable impedance measurement system to conduct the EIS studies on the fruits during ripening and storage. The proposed laboratory based EIS system is developed with a Microcontroller ATmega16, a Direct Digital Synthesizers based constant current source AD5930, a current to voltage converter, a low pass filter, and a DSO. To test and evaluate the developed system, the cucumber impedance is studied under the storage condition using EIS to characterize the cucumber freshness from the electrical impedance data. The real parts, imaginary parts of the cucumber impedance are calculated and the Nyquist diagrams are analyzed to study the equivalent circuit analysis. The developed system is compared with a standard impedance analyzer and it is observed that the results obtained from the developed system closely match with the data measured by the commercial impedance analyzer. The developed system is also found suitable for EIS studies of fruits, vegetables, and other biological tissues. The developed system is found low‐cost, fast, and user friendly. PCB based version of the proposed system with display unit will be found as a portable, standalone, and EIS system suitable for outdoor measurement in agricultural‐field applications.
Practical applications
Microcontroller based low cost electrical impedance spectroscopy (EIS) has been developed and is studied for EIS based fruit ripening analysis. The system is compared with the standard commercial impedance analyzer and it is found suitable fruit ripening characterization, vegetable freshness detection, and health studies of other biological tissues. The microcontroller based EIS system is found portable, low cost, fast, and user friendly device which can be used in laboratory, cultivation fields, cold storages and shops and markets. The developed system allows nontechnical person to operated and collect the data from fruit and vegetable samples. The system acquired data significantly correlate the bioimpedance variation with the ripening states which can be potentially utilized to study the fruit ripening noninvasively at low cost. Hence the product‐form of the developed devise could even be operated by field persons, farmers, and other common men to evaluate the fruit ripening and vegetable freshness. 相似文献
Semi-rigid films or skins form at the interface of crude oil and water as a result of the accumulation of asphaltene and resin fractions when the water-immiscible crude oil is contacted with water for a period of time or "aged". The time varying patterns of area-independent mass transfer coefficients of two compounds, benzene and naphthalene, for dissolution from crude oil and gasoline were determined. Aqueous concentrations of the compounds were measured in the eluent from flow-through reactors, where a nondispersed oil phase and constant oil-water interfacial area were maintained. For Brent Blend crude oil and for gasoline amended with asphaltenes and resins, a rapid decrease in both benzene and naphthalene mass transfer coefficients over the first few days of aging was observed. The mass transfer coefficients of the two target solutes were reduced by up to 80% over 35 d although the equilibrium partition coefficients were unchanged. Aging of gasoline, which has negligible amounts of asphaltene and resin, did not result in a change in the solute mass transfer coefficients. The study demonstrates that formation of crude oil-water interfacial films comprised of asphaltenes and resins contribute to time-dependent decreases in rates of release of environmentally relevant solutes from crude oils and may contribute to the persistence of such solutes at crude oil-contaminated sites. It is estimated that the interfacial film has an extremely low film mass transfer coefficient in the range of 10(-6) cm/min. 相似文献
The effect of age and peroxidative stress on the concentration of a deoxyguanosine malondialdehyde adduct (dG-MDA) in rat
tissues was investigated. Vitamin E deficiency had not effect on the dG-MDA content of liver DNA in rats fed a diet containing
10% corn oil. When 2% cod liver oil was added to this diet, the dG-MDA content of liver DNA doubled in the positive controls
fed a high level of vitamin E (100 ppm dl-α-tocopherol), and there was a further increase when vitamin E was deleted. Neither
iron nitrilotriacetate administration nor choline deficiency had any effect on the dG-MDA content of liver DNA. Carbon tetrachloride
had a lowering effect. The failure of iron or carbon tetrachloride administration and of vitamin E deficiency to increase
liver dG-MDA is consistent with their failure in previous experiments to affect the urinary excretion of dG-MDA. In contrast,
these forms of peroxidative stress produce large increments in the urinary excretion of MDA adducts with lysine, reflecting
increased formation and degradation of MDA-modified proteins. DNA appears to be protected from modification by MDA produced
at extranuclear sites. The frequency of dG-MDA in different tissues of 4-month-old rats varied markedly: brain ≫ liver > kidneys
and testes. Higher concentrations of dG-MDA were found in the liver and kidneys, but not the testes, of 25-month-old rats.
The determinants of the concentration of dG-MDA in DNA merit further investigation. 相似文献