Ga Solution Research Articles

Method development for the determination of chlorine by high-resolution graphite furnace molecular absorption spectrometry via GaCl

In this study, a method was developed for the determination of chlorine via molecular absorption of GaCl at 249.060 nm generated in a graphite furnace of a high-resolution continuum source atomic absorption spectrometer. For this purpose, 25 μg of Ga and standard solutions or samples were mixed on the platform. The optimized pyrolysis and vaporization temperatures were 500 and 1100 °C, respectively, which were uncommonly low compared to other diatomic molecules between chlorine and molecule forming reagents of chlorine and non-metals. The limit of detection for the method was 2.3 ng which was sufficient to determine chlorine in samples to be analyzed in this study as well as in many matrices. The Cl concentration was determined in uncertainty limits of a certified wastewater sample. Finally, Cl concentrations in some milk and mineral water samples were determined using aqueous standards for calibration. The results were compared with those found by analyte addition technique and no significant difference was found.

Proteomic analysis of Zanthoxylum nitidum seeds dormancy release: Influence of stratification and gibberellin

Zanthoxylum nitidum (Roxb.) DC. is one of the most important economic crops on account of its value as a Chinese herbal medicine (Zanthoxyli radix), health product and daily chemical raw materials. Zanthoxylum nitidum seeds are characterized to be an intermediate physiological dormancy that requires three months of cold stratification (4 °C) or gibberellin (GA) treatment (300 mg L−1, soaking for two days) to relieve seed dormancy and promote germination. Exploring the changes of proteins and related biosynthetic and metabolic pathways during seed dormancy release will contribute to expand our knowledge of this process. In this study, mature Zanthoxylum nitidum seeds from Pingyuan County, Guangdong province were treated with cold stratification and GA solution. The differently expressed proteins after treatments were characterized by iTRAQ coupled LC–MS/MS. In total, 484 proteins showed that at least 1.3-fold differences in abundance were detected after treatments; a majority of the differently abundant proteins are involved in the respiration-related metabolism processes, biosynthesis of amino acids and translation during the dormancy release of Zanthoxylum nitidum seeds. This study is the first to use the iTRAQ-based proteomics approach to analyse the proteome of Zanthoxylum nitidum seeds, pointing out the direction for our further research on the pathways and even the key genes and proteins associated with the dormancy release of Zanthoxylum nitidum seeds.

An Improved Genetic Algorithm to Optimize Spatial Locations for Double-Wishbone Type Suspension System with Time Delay

By taking account of double-wishbone independent suspension with two unequal-length arms, the coordinate values of articulated geometry are based on structural limitations and constraint equations of alignment parameters. The sensitivities of front wheel alignment parameters are analyzed using the space analytic geometry method with insight module in ADAMS® software. The multiobjective optimization functions are designed to calculate the coordinate values of hardpoints with front suspension since the effect of time delay due to wheelbase can be easily obtained by vehicle speed. The K&C characteristics have been investigated using GA solutions in the simulation environment. The camber angle decreases from 1.152° to 1.05° and toe-in angle reduces from 1.036° to 0.944°. The simulation results demonstrate that the suggested optimization method is able to satisfy the suspension motion to enhance ride comfort. Experimental results, obtained by K&C test bench, also indicate that the optimized suspension can track the desired trajectory while keeping the vehicle performance in various road conditions.

Adjustment of Induced Time by Electrochemical Activation of Electrode Surface for Rapid Ga Electrodeposition

Rapid electrodeposition is crucial for the industrial production of Ga from a low-concentration Ga solution. Herein, the induced time for Ga electrodeposition was examined and an effective method to shorten the induced time by anodic activation of a stainless-steel electrode surface was proposed. The adjustment mechanism of the induced time was analyzed based on the evolution of the surface structure (i. e. nucleation site and wettability). The results indicated that an extended induced time for Ga electrodeposition resulted from stainless-steel cathode without activation. With anodic surface activation in a H2SO4 solution, the induced time was shortened from 4.75 h to 20 min. It may be related to the increased surface roughness, which provides more nucleation sites for Ga electrodeposition. Meanwhile, the wettability was also improved, which accelerates the rapid separation of hydrogen bubbles. Therefore, rapid Ga electrodeposition from a low-concentration Ga solution was achieved with a short induced time and a high current efficiency.

Effects of exogenous hormones like acc on germination of lettuce seeds

In order to investigate the effects of different exogenous hormones on the dormancy and germination of lettuce seeds, this paper soaks the lettuce seeds in ACC, GA, CaCl2 and SNP solutions with different concentrations, respectively, observes the quantity of lettuce seeds germinated, calculates the germination rate, and analyzes the optimum concentrations to break the period of dormancy and promote the germination of seeds to increase the germination rate of seeds. Through the observation of lettuce seeds soaked with ACC, GA, calcium chloride and SNP in different time periods, it is found that ACC, GA, calcium chloride and SNP solutions can all promote the germination of lettuce seeds. Lettuce falls within the Lactuca genus, the Asteraceae family. It likes cold climate and the suitable temperature for growth is 15-20°C. If the temperature exceeds 25°C, the high temperature in the leafy head will cause the necrosis and rot and poor growth of interior leaves (Song et al., 2013). The temperature for germination of seeds ranges between 15-20°C. If the temperature is higher than 25°C, the seed coat will not be able to absorb water, affecting the germination (Li et al., 2012). When lettuce is sowed in summer, it needs to be treated at a low temperature. After being soaked, it should be placed in the refrigerator freezer to accelerate germination and should not be sowed until the sprout turns white. Lettuce is rich in protein, sugar, vitamins, minerals and other nutrients. It is popular among consumers due to its crisp texture, fresh taste and fragrance and rich nutrition (Hu and Zhan, 2014). Few research has been conducted on the effects of exogenous hormones on the germination rate of lettuce seeds. This study takes lettuce seeds from the same source as the test material and conducts tests on the germination rate of lettuce seeds, trying to explore the effects of ACC, GA, CaCl2 and SNP solutions with different concentrations on the germination rate of lettuce seeds so as to improve the germination rate.

68(Ge+Ga) activity standardization by 4πβ(LS)-γ(NaI(Tl)) anticoincidence counting measurements

In this work, a 68(Ge+Ga) solution has been standardized at the National Institute of Ionizing Radiation Metrology (LNMRI), in Brazil, in the frame of an international key comparison CCRI(II)-K2.Ge-68 piloted by National Institute of Standards and Technology (NIST/USA). The 4πβ(LS)-γ(NaI(Tl)) anticoincidence method with live-time and extended dead-time was used and its result was validated by 4πβ(LS)-γ(NaI(Tl)) coincidence counting and liquid scintillation counting using the Triple to Double Coincidence Ratio (TDCR) method. The deviations of the activity concentration values of coincidence and TDCR measurements from the anticoincidence result were 1.7% and 0.63%, respectively, which were within experimental evaluated uncertainties at ~95% level of confidence (coverage factor k = 2). The combined relative standard uncertainties were 0.65%, 0.70% and 0.53% for anticoincidence, coincidence and TDCR methods, respectively. These values are consistent with the results reported by Cessna at the ICRM2017 conference.

Numerical optimization for vibration and noise of the wheel based on PSO-GA method

Currently, those reported researches conducted optimal design for the wheel only in order to reduce the tread wear and increase the service life, but they did not consider the wheel vibration and radiation noise which seriously influence people’s life and did not achieve obvious noise reduction effects. Aiming at this question, a multi-body dynamic model of the high-speed train was established, and the vertical and radial force was extracted to input into the finite element model of the wheel to compute its vibration characteristics. Then, the wheel was conducted on a multi-objective optimization based on particle swarm optimization improved by genetic algorithm (PSO-GA) method. Finally, the optimized vibration results were mapped to the acoustic element model to compute the radiation noise of the wheel. The computational model was also validated by experimental test. In order to observe the optimized effect, the optimized results were compared with those of the traditional GA and PSO method. Solutions of the traditional GA and PSO method were relatively dispersed during iterations and the algorithm could easily fall into the locally optimal solution. The optimized results of PSO-GA method were obviously better. Compared with the original wheel, the vibration acceleration was reduced by 22.9 %, and the mass was reduced by 1.1 %. Finally, the optimized vibration was mapped to the boundary element model to compute the radiation noise of the wheel, and the computational results were compared with the original wheel. Radiation noises of the original wheel were obviously more than that of the optimized wheel, and there were a lot of obvious peak noises in the original wheel. Radiation noises of the optimized wheel only had two obvious noise peaks in the analyzed frequency. Therefore, a wheel with low noises and lightweight was achieved in this paper.

Synthesis and properties of γ-Ga2O3–Al2O3 solid solutions

The textural and structural properties of mixed oxides Ga2O3–Al2O3, obtained via impregnating γ-Al2O3 with a solution of Ga(NO3)3 and subsequent heat treatment, are studied. According to the results from X-ray powder diffraction, gallium ions are incorporated into the structure of aluminum oxide to form a solid solution of spinel-type γ-Ga2O3–Al2O3 up to a Ga2O3 content of 50 wt % of the total weight of the sample, accompanied by a reduction in the specific surface area, volume, and average pore diameter. It is concluded that when the Ga2O3 content exceeds 50 wt %, the β-Ga2O3 phase is observed along with γ-Ga2O3–Al2O3 solid solution. 71Ga and 27Al NMR spectroscopy shows that gallium replaces aluminum atoms from the tetrahedral position to the octahedral coordination in the structure of γ-Ga2O3–Al2O3.

Bezier Curve Based Path Planning in a Dynamic Field using Modified Genetic Algorithm

Mobile robots have been used in different applications such as assembly, transportation, and manufacturing. Although, the great work to get the optimum robot's path, traditional path planning algorithms often assume that the environment is perfectly known and try to search for the optimal path that contains sharp turns and some polygonal lines. This paper proposes an efficient, Bezier curve based approach for the path planning in a dynamic field using a Modified Genetic Algorithm (MGA). The proposed MGA aims to boost the diversity of the generated solutions of the standard GA which increases the exploration capabilities of the MGA. In our proposed method, the robot's path is dynamically decided based on the obstacles’ locations. With the goal of optimizing the distance between the start point and the target point, the MGA is employed to search for the most suitable points as the control points of the Bezier curve. Using the chosen control points, the optimum smooth path that minimizes the total distance between the start and the end points is selected. Our model was tested on different environments with different scales, different numbers of obstacles, and six benchmark maps. As a result, the proposed method provides an efficient way to avoid robot's energy consumption in harsh environments.

3-D architecture between indium tin oxide nano-rods and a solution processed CuInGaS2 absorber layer for thin film solar cells

The performance of thin film solar cells can be significantly enhanced by efficient light management. In this study, we integrated one-dimensional indium tin oxide (ITO) nanorods into CuInGaS2 (CIGS) films to fabricate 3-D nanostructured thin film solar cells. 400, 600, and 1000nm ITO nanorod substrates were used as back contact electrodes. Precursor solutions of Cu, In, and Ga with and without binder materials were prepared to fill the gaps between the ITO nanorods and increase the thickness of the CIGS films, respectively. Heat treatments both in air and in H2S were applied to form polycrystalline CIGS films while minimizing carbon impurities. 3-D nanostructured solar cell devices with Al,Ni/AZO/i-ZnO/CdS/CIGS/ITO nanorods/Glass structures were fabricated and characterized. Under standard irradiation conditions, the 600nm ITO nanorod solar device was found to have the maximum power conversion efficiency of 6%. This superior efficiency may be attributed to enhanced light absorption and complete gap filling.

Kinetics of Hydrogenation of Serine and Glutamic Acid in Aqueous Solution over a Ru/C Catalyst

Two amino acids, serine (SE, 2-amino-3-hydroxypropanoic acid) and glutamic acid (GA, 2-amino-pentanedioic acid), are widely regarded as attractive, renewable platform chemicals. Catalytic hydrogenation of these amino acids to amino alcohols is a crucial step in making many useful products. In this work, the kinetics of hydrogenation of aqueous solutions of SE and GA was investigated over a heterogeneous Ru/C catalyst. Hydrogenation trials were performed in the kinetics-control regime in a batch reactor at 383 and 403 K. Serinol (2-amino-1,3-propanediol) and 2-amino-1,5-pentanediol were the major hydrogenation products, correspondingly. The effects of the concentrations of the reactants (viz. amino acid and H2) and catalyst on the rates of disappearance of the acids and hence the turnover frequency (TOF) were studied. Also, the influence of addition of phosphoric acid on the hydrogenation process was investigated. From power-law kinetics, the apparent energy of activation for the reactions with SE and GA w...

Development and validation of High-performance Thin-layer Chromatography Method for Simultaneous Determination of Polyphenolic Compounds in Medicinal Plants.

Context:Quantitative standardization of plant-based products is challenging albeit essential to maintain their quality.Aims:This study aims to develop and validate high-performance thin-layer chromatography (HPTLC) method for the simultaneous determination of rutin (Ru), quercetin (Qu), and gallic acid (Ga) from Psidium guajava Linn. (PG) and Aegle marmelos (L.) Correa. (AM) and correlate with antioxidant activity.Materials and Methods:The stock solution (1 mg/mL) of standard Ru, Qu, and Ga in methanol: Water (1:1) was serially diluted and spotted (5 μL) on slica gel 60 F254 thin-layer chromatography plates. Toluene: Ethyl acetate: Formic acid: Methanol (3:4:0.8:0.7, v/v/v) was selected as mobile phase for analysis at 254 nm. Hydroalcoholic (1:1) extracts of leaves of PG and AM were fractionated and similarly analyzed. Antioxidant activity was also determined using 2, 2-diphenyl-1-picrylhydrazyl assay.Results:The developed method was robust and resolved Ru, Qu, and Ga at Rf 0.08 ± 0.02, 0.76 ± 0.01, and 0.63 ± 0.02, respectively. The intra-day, interday precision, and interanalyst were <2% relative standard deviation. The limit of detection and limit of quantification for Ru, Qu, and Ga were 4.51, 4.2, 5.27, and 13.67, 12.73, 15.98 ng/spot, respectively. Antioxidant activity (Log 50% inhibition) of PG and AM was 4.947 ± 0.322 and 6.498 ± 0.295, respectively.Conclusion:The developed HPTLC method was rapid, accurate, precise, reproducible, and specific for the simultaneous estimation of Ru, Qu, and Ga.SUMMARYHPTLC method for simultaneous determination and quantification of Rutin, Quercetin and Gallic acid, is reported for quality control of herbal drugs.Abbreviations Used: A: Aqueous fraction; AM: Aegle marmelos L. Correa; B: Butanol fraction; C: Chloroform fraction; EA: Ethyl acetate fraction; Ga: Gallic acid; H: Hexane fraction; HA: Hydroalcoholic extract; HPTLC: High-performance thin-layer chromatography; PG: Psidium guajava; Qu: Quercetin; Ru: Rutin.

Formation and Stabilization of Vaterite Calcium Carbonate by Using Natural Polysaccharide

This paper aimed to study the effects of natural polysaccharide (gum arabic, GA) on the formation of vaterite calcium carbonate and its stability in aqueous solution. Gum arabic is a macromolecule that has a high molecular weight and is amphoteric in character. A 0, 2.5, 5 or 10 ml of GA solution (30%) was added to the calcium chloride solution with various initial concentrations to prepare the vaterite calcium carbonate. The calcium carbonate particles were characterized using FTIR, XRD, SEM, TEM and DSC-TG as well as calculation of phase contents. The results of XRD and FTIR analysis were showing that the presence of GA during the precipitation changes the behavior of calcium carbonate to form vaterite until at lower dose used. In addition, the molar content of vaterite increased at the expense of content of calcite with increasing the GA dose. There are slightly improvements in the vaterite content by increasing the initial concentration. The formed vaterite calcium carbonates composed of aggregates as broccoli-like or spherical shape and with particle size 1.6 - 2.5 μm in diameter. TEM images showed that these aggregates composed of the sub spherical unit with diameter 15 - 30 nm. The thermal behavior of prepared vaterite was conformed the mineral composition of these phases. The prepared calcium carbonate, which is formed in the presence of different doses of gum, has a stability in the aqueous solutions at different temperatures, as the analyzes indicated that a very small percentage of the vaterite were converted to calcite. The gum arabic prevented or depressed the transformation of vaterite to calcite through capped the surface of particles, i.e. it is more effective in stabilizing the vaterite phase with increasing in initial concentration and time.

Photoluminescence studies of GaSbBi quantum dots grown on GaAs by liquid phase epitaxy

Liquid phase epitaxial growth from a saturated GaSb solution in Ga with 1.3 at.% Bi, on GaAs substrates is shown to produce quantum dots with a Bi content of 0.5 at.%. The height and dimensions of the QDs are investigated by field effect scanning electron microscopy and atomic force microscopy. The density of the small QDs is approximately 4.3 × 109cm−2, with dimensions in the range of 20–100 nm and height of ∼10 nm. Theoretical calculations reveal that the QDs have band alignment structure of type-II as predicted from GaSbBi bulk band structure. The 12 K photoluminescence (PL) of the QDs shows broad emission band in the range 1.25–1.37 eV. Gaussian deconvolution is used to resolve the broad peak into three individual PL emission peaks which are thoroughly explored by their dependence on temperature and excitation power.

Standardisation of a 68(Ge+Ga) solution within the CCRI(II)-K2.Ge-68 key comparison

This paper presents the work performed in IFIN-HH, Radionuclide Metrology Laboratory, for the standardization of a 68(Ge+Ga) solution, within our participation in the key-comparison codified as CCRI(II)-K2.Ge-68, organised by the CIPM-CCRI(II). Four methods were used: (i) the 4πβ(PC)-γ coincidence method, efficiency extrapolation variant, (ii) the liquid scintillation counting in the variant of triple to double coincidence ratio, (iii) the gamma-ray spectrometry and (iv) the well-type ionisation chamber measurement. The final result was calculated as “power moderate weighted mean” of all results. The results obtained in all methods are presented as relative figures.

Immobilization of Cyclooxygenase-2 on Silica Gel Microspheres: Optimization and Characterization.

In this study, immobilized COX-2 was successfully constructed through glutaraldehyde-mediated covalent coupling on functional silica gel microspheres. The optimum conditions, properties, and morphological characteristics of the immobilized COX-2 were investigated. The optimal immobilization process was as follows: about 0.02 g of aminated silica gel microspheres was activated by 0.25% GA solution for 6 h and mixed with 5 U of free recombinant COX-2 solution. Then, the mixture was shaken for 8 h at 20 °C. Results showed that the immobilized COX-2 produced by this method exhibited excellent biocatalytic activity, equivalent to that of free COX-2 under the test conditions employed. The best biocatalytic activity of immobilized COX-2 appeared at pH 8.0 and still maintained at about 84% (RSD < 7.39%, n = 3) at pH 10.0. For temperature tolerance, immobilized COX-2 exhibited its maximum biocatalytic activity at 40 °C and about 68% (RSD < 6.99%, n = 3) of the activity was maintained at 60 °C. The immobilized COX-2 retained over 85% (RSD < 7.26%, n = 3) of its initial biocatalytic activity after five cycles, and after 10 days storage, the catalytic activity of immobilized COX-2 still maintained at about 95% (RSD < 3.08%, n = 3). These characteristics ensured the convenient use of the immobilized COX-2 and reduced its production cost.

Corrosion behavior of 316L stainless steel anode in alkaline sulfide solutions and the consequent influence on Ga electrowinning

During Ga enrichment by ion exchange, sodium sulfide is an indispensable compound to elute Ga (III) from resin. The effects of residual S2− ions on the corrosion behavior of stainless steel anode and Ga electrodeposition are studied. It is found that 316L stainless steel anode is corroded seriously and Ga is hardly electrodeposited in the presence of 2.17g/L S2−. The adsorption of HS− ions damages the passive film of anode surface, which leads to the formation of soluble and colloidal (NaFeS2)n. After 48h electrowinning, the weight loss of stainless steel anode (7.38mg/cm2) in Ga solution with 2.17g/L S2− is much larger than that (0.23mg/cm2) in solution without S2−. Green-black precipitates are found in Ga (III) solution due to the degradation of colloidal (NaFeS2)n. Meanwhile, the corrosion of stainless steel anode brings iron ions into Ga (III) solution. Iron species are deposited or absorbed on the cathode, which is unfavorable to Ga electrodeposition. At lower S2− concentration, both Fe and O are detected in Ga coatings. When S2− concentration is up to 2.17g/L S2−, Ga electrodeposition is completely inhibited.

Direct formation and phase stability of luminescent γ-Ga2O3 spinel nanocrystals via hydrothermal method

Nanocrystals of γ-gallium oxide (γ-Ga2O3) were directly synthesized as a single phase of spinel-type structure from the aqueous precursor solution of Ga(NO3)3 or Ga2(SO4)3 under weakly basic conditions in the presence of citric acid by mild hydrothermal method. The crystallite size of γ-Ga2O3 spinel that was hydrothermally formed at 180–240 °C for 5 h was in the dimension range from 5 to 9 nm. The optical band gap of the as-prepared γ-Ga2O3 was 4.88 eV. The γ-Ga2O3 nanocrystals synthesized at 180 °C showed a broad-band visible violet–blue light emission with a peak wavelength at 410 nm, centered at around 425 nm under excitation at 325 nm. The emission intensity of γ-Ga2O3 synthesized at 210 and 240 °C was lower than that of 180 °C. The spinel-type structure of γ-Ga2O3 was maintained up to 600 °C. The γ-Ga2O3 phase fully transformed into β-Ga2O3 after heating at 800 °C. The luminescence intensity of gallium oxide decreased, and the peak wavelength of emission spectrum shifted into lower wavelengths via heat treatment at 600 and 800 °C for 1 h in air.

The corrosion resistance of Ni anode and Ga electrowinning in alkaline sulfide solutions

In this paper, a nickel anode was used for Ga electrowinning in the presence of S2- ions. The corrosion resistances of nickel and stainless steel electrodes in alkaline solutions of S2- were studied by cyclic voltammetry, XPS, and weight loss measurements. Ga electrowinning was carried out in Ga solutions with high concentrations of S2- at different current densities and NaOH concentrations. The results indicated that the nickel anode showed better corrosion resistance than the stainless steel anode. The corrosion rate of nickel was much lower than that of stainless steel due to the formation of stable passive films consisting of Ni oxide and hydroxide. The corrosion rate of the nickel anode was only 0.28 mg cm(-2) after 48 h electrowinning in the presence of 5 g L-1 S2- ions. The corrosion resistance of the nickel anode was almost independent of the NaOH concentration and the current density. When the nickel anode was used for Ga electrowinning, the current efficiency (QE) decreased in the presence of S2- owing to the reduction of the incomplete oxidation products of S2- on the cathode. The complete oxidation of S2- to SO4 (2-) was accelerated on the nickel anode, which lowered the concentrations of S2- and that of its incomplete oxidation products in solution. Bright, high-purity metallic gallium was obtained when using the nickel anode, even in Ga(III) solutions of 5 g L-1 S2-. Therefore, nickel was a suitable anode material for Ga electrowinning in Ga solutions of S2- ions.

유기금속화학증착 분진(MOCVD dust)을 이용한 갈륨 함유 고순도 수용액 제조 연구

Abstract In this study, we have investigated solvent extraction of Ga and recovery of high pure Ga solution from MOCVD dust formanufacturing of LED chip. Effect of extractan, concentration of extractant were examined for choosing the more effectiveextractant and high pure Ga solution was fabricated by multi-stage extraction/stripping process. For extraction/separation of Gabased on the analysis of raw-material in previous study, 3 different extractants PC 99A, DP-8R, Cyanex 272 has been inves-tigated and the extraction efficiency of 1.5 M Cyanex 272 was 43.8%. It was conformed that extraction efficiency of Ga was83% in multi-stage extraction and 5N high purity Ga stripping solution without impurities also obtained.Key words : MOCVD dust, Ga purification, solvent extraction, Cyanex 272 · Received : June 25, 2015 · Revised : July 15, 2015 · Accepted : July 24, 2015Corresponding Author : Chan Gi Lee (E-mail : cglee@iae.re.kr)Advanced Materials & Processing Center, Institute for Advanced Engineering, 175-28, 51 Goan-ro, Baegam-myeon, Cheoin-gu,Youngin-si, Gyeonggi-do, 449-863, KoreaⓒThe Korean Institute of Resources Recycling. All rights reserved. This is an open-access article distributed under the termsof the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/), which permitsunrestricted non-commercial use, distribution and reproduction in any medium, provided the original work is properly cited.