Microwave response of an HEMT photoconductor

Interdigitated photodetectors of various geometries have been fabricated on GaAlAs/GaAs heterostructure material. Optical response characteristics of these devices have been examined at both dc and microwave frequencies. The microwave response, at frequencies to 8 GHz, was studied by illuminating the devices with the output of an internally modulated GaAlAs diode laser. Results of these measurements are presented and compared with that of GaAs photoconductors

Measurement techniques for cryogenic Ka-band microstrip antennas

The measurement of cryogenic antennas poses unique logistical problems since the antenna under test must be embedded in a cooling chamber. A method of measuring the performance of cryogenic microstrip antennas using a closed cycle gas cooled refrigerator in a far field range is described. Antenna patterns showing the performance of gold and superconducting Ka-band microstrip antennas at various temperatures are presented

Optical control of an 8-element Ka-band phased array using a high-speed optoelectronic interconnect

Optical distribution of control signals in electronically steered phased array antennas is being considered. A demonstration experiment is described in which a high speed hybrid GaAs optoelectronic integrated circuit (OEIC) was used to control an eight element phased array antenna. The OEIC, which accepts a serial optical control signal as input and converts it to 16 demultiplexed parallel outputs, was used to control the monolithic GaAs phase shifters of a Ka-band patch panel array antenna. Antenna pattern switching speeds of 2.25 microsec, limited by interface circuitry, were observed

Adsorption and Photocatalytic Performance of Activated Carbon and Activated Carbon-La2O3 nanoparticles Composites for Malachite Green

In present study, the removal of Malachite Green (MG) dye by Activated Carbon and Activated Carbon- Lanthanum Oxide nanoparticles composites were investigated. La2O3 nanoparticles were prepared by Precipitation method and Activated Carbon-La2O3 nanoparticles composites were prepared by impregnation method. Activated Carbon and synthesized Activated Carbon-Lanthanum Oxide nanoparticles composites were characterized by FTIR spectroscopy, X- ray diffraction (XRD), Field emission gun scanning electron microscopy (FEG-SEM) and High-resolution transmission electron microscopy (HR-TEM) for surface morphological and crystalline size determination. The X-ray diffraction patterns revealed that the particles exhibited a crystal structure at the suitable temperature. The average particle size of the nanocomposites from the X-ray diffraction is about 33-44nm and also scanning electron microscopy shows good morphology and exhibited clearly cubic and hexagonal shape. The Transmission electron microscopy (TEM) shows the crystalline size of structures is 34-43 nm. Further, the photocatalytic degradation of Malachite Green dye was measured by visible absorption spectroscopy using Activated Carbon and Activated Carbon-La2O3 nanoparticles composites. To obtain the optimal conditions for the dye degradation, the effect of various experimental parameters, like amount of adsorbents, pH, concentration of dye, contact time and light intensity on the rate of reaction was studied. A tentative mechanism for the photocatalytic degradation of Malachite Green was proposed. Photocatalytic degradation of Malachite Green dye followed pseudo first-order kinetics. It was found that the dye degradation gave the best results at a pH of 8, MG Dye concentration 200 ppm and using 70 mWcm–2 light intensity with 0.080 g of adsorbent. At room temperature, the maximum removal of dye was achieved in 60 min. It was found that the percentage of dye removal was improved from 90.24% for Activated Carbon to reach 98.11% for Activated Carbon-La2O3 nanoparticles composites

Visible Light-Assisted Degradation of Malachite Green dye using Waste Tea-Mediated Zinc Nanoparticles

This work presents entirely a new, green, and non-expensive route of synthesis of zinc nanoparticles (NPs) using waste tea. The crystalline nature of waste tea-mediated Zn NPs (WT-ZnO NPs) was confirmed by XRD and SAED analyses. Further characterizations of WT-ZnO NPs were done using UV-vis spectroscopy, FTIR spectroscopy, SEM- EDX, and TEM. The size of synthesized NPs was calculated to be 15.1 nm which presented spherical morphology with some sorts of agglomeration. The WT-ZnO NPs when applied as visible light-driven photo catalyst for degradation of Malachite green dye. Adsorptions of Malachite green (MG) dye follow pseudo-first-order kinetics. It was found that the dye degradation showed best results in the presence of sunlight at a pH of 3, Malachite green (MG) Dye concentration 50 ppm with 60 mg of WT-ZnO NPs. At room temperature, the maximum removal of dye was achieved in 105 min by stirring. Malachite green (MG) showed that degradation was 96.45 % in the presence of visible light and 81.5% in the presence of sun light within the experimental time. The highly pure, WT-ZnO NPs are considered to have comparable photocatalytic activity with respect to most of the reported works and hence might find a way for its practical application for waste water treatment in the real world. The WT-ZnO NPs could be reused at least for three times without any significant loss in degradation efficiency

Effective and Feasible Photocatalytic Degradation of Janus Green B dye in Aqueous Media using PbS/CTAB Nanocomposites

In this Chapter, we demonstrated the synthesis of Lead sulphide by using low-cost chemical displacement method. We used thioacetamide for the source of sulphide ion and for the source metal salt; lead nitrate was used. The structural, morphological, metal percentage and optical properties of as synthesized nanoparticles are investigated by using X-ray diffraction (XRD), Uv-Visible spectra; Field emission gun Scanning electron microscopy (FEG-SEM) with EDS, Fourier transforms infrared spectroscopy (FTIR), High-resolution transmission electron microscopy (HR-TEM) and Photoluminescence spectroscopy (PL).The average particle size of the nanoparticles from the x-ray diffraction is about 20 nm and also field emission gun Scanning electron microscopy shows good morphology and exhibited clearly cubic shape. Further, the photocatalytic degradation of Janus green B dye was measured by visible absorption spectroscopy. To obtain the optimal conditions for the dye degradation, the effect of various experimental parameters, i.e., pH, amount of nanoparticles, concentration of dye and light intensity on the rate of reaction was studied. It was found that the JGB dye degradation gave the best results at a pH of 7.0, dye concentration= 200 ppm and using a 70 mW·cm–2 light intensity with 0.5 g of PbS nanoparticles. At room temperature, the photocatalytic degradation of Janus green B dye was observed about 93.5%

Efimov states and their Fano resonances in a neutron-rich nucleus

Asymmetric resonances in elastic n+$^{19}$C scattering are attributed to Efimov states of such neutron-rich nuclei, that is, three-body bound states of the n+n+$^{18}$C system when none of the pairs is bound or some of them only weakly bound. By fitting to the general resonance shape described by Fano, we extract resonance position, width, and the "Fano profile index". While Efimov states have been discussed extensively in many areas of physics, there is only one very recent experimental observation in trimers of cesium atoms. The conjunction that we present of the Efimov and Fano phenomena may lead to experimental realization in nuclei.Comment: 4 double-column pages, 3 figure

Solar Light Induced Photo Catalytic Properties of α-Fe2O3 Nanoparticles for Degradation of Methylene Blue Dye

The present work describes α-Fe2O3 nanoparticles are prepared by chemical displacement method using CTAB as a stabilizing agent. Glutaric acid as fuel and metal salt like ferrous sulphate was used in synthesis. The structural, morphological, metal percentage and optical properties of as synthesized nanoparticles are investigated by using x-ray diffraction (XRD), UV-Visible Spectra; field emission gun Scanning electron microscopy (FEG-SEM) with EDS, Fourier transforms infrared spectroscopy (FTIR), High-resolution Transmission electron microscopy (HR-TEM) and Photoluminescence Spectroscopy (PL). The photocatalytic degradation of Methylene Blue dye was measured by visible absorption spectroscopy. To obtain the most favorable conditions for degradation of MB dye, the effect of various experimental parameters, i.e., pH, amount of nanoparticles, concentration of dye and light intensity on the rate of reaction was studied. A tentative mechanism for the photocatalytic degradation of Methylene Blue was proposed. Photocatalytic degradation of Methylene Blue dye followed pseudo first-order kinetics. It was found that the dye degradation gave the best results at a pH of 6.0, and using a 70 mW•cm–2 light intensity with 0.3 g of α-Fe2O3 nanoparticles. At room temperature, the photocatalytic degradation of Methylene Blue dye was observed about 92.3%

Subcellular location prediction of proteins using support vector machines with alignment of block sequences utilizing amino acid composition

Background: Subcellular location prediction of proteins is an important and well-studied problem in bioinformatics. This is a problem of predicting which part in a cell a given protein is transported to, where an amino acid sequence of the protein is given as an input. This problem is becoming more important since information on subcellular location is helpful for annotation of proteins and genes and the number of complete genomes is rapidly increasing. Since existing predictors are based on various heuristics, it is important to develop a simple method with high prediction accuracies. Results: In this paper, we propose a novel and general predicting method by combining techniques for sequence alignment and feature vectors based on amino acid composition. We implemented this method with support vector machines on plant data sets extracted from the TargetP database. Through fivefold cross validation tests, the obtained overall accuracies and average MCC were 0.9096 and 0.8655 respectively. We also applied our method to other datasets including that of WoLF PSORT. Conclusion: Although there is a predictor which uses the information of gene ontology and yields higher accuracy than ours, our accuracies are higher than existing predictors which use only sequence information. Since such information as gene ontology can be obtained only for known proteins, our predictor is considered to be useful for subcellular location prediction of newly-discovered proteins. Furthermore, the idea of combination of alignment and amino acid frequency is novel and general so that it may be applied to other problems in bioinformatics. Our method for plant is also implemented as a web-system and available on http://sunflower.kuicr.kyoto-u.ac.jp/~tamura/slpfa.html webcite