http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Electron-Electron Interactions based Metal-Insulator Transition in Ga Doped ZnO Thin Films
R V Muniswami Naidu,A Subrahmanyam,A Verger,M K Jain,S V N Bhaskara Rao,S N Jha,D M Phase 대한금속·재료학회 2012 ELECTRONIC MATERIALS LETTERS Vol.8 No.4
We report on the charge carrier transport mechanisms of undoped and Ga doped (2 wt. % and 4 wt. %)ZnO thin films grown by pulsed dc magnetron sputtering technique. Temperature dependent resistivity measurements showed typical semiconducting behaviour for undoped ZnO thin films where as Ga doped ZnO thin films showed metallic nature at higher temperatures and insulating nature with a metal to insulator transition at lower temperatures. The observed transition temperatures are 91 K and 140 K for 2 wt. % and 4 wt. %Ga doped ZnO films respectively. The observed metal insulator transition is attributed to the electron-electron interactions at low temperatures. The variations in the transition temperatures are explained based on the disorderness induced in the system due to the doping effect. ZnO doped with 4 wt. % Ga showed the lowest resistivity of 5.7 × 10−4Ω cm with a carrier concentration of 1.2 × 1021/cm3. Undoped and doped ZnO thin films are about 90% transparent in the visible region. Blue shift is observed in the absorption edge with the effect of doping and it is explained based on B-M shift. The Fermi level measured from valance band spectroscopy showed a shift of +0.6 eV for 2 wt. % Ga doped ZnO thin film and +0.7 eV for 4 wt. %Ga doped ZnO thin film compared to the Fermi edge of undoped ZnO thin films. This ascertains the movement of Fermi level in to the conduction band with the effect of doping.
Leaching of rare earth metals (REMs) from Korean monazite concentrate
Panda, R.,Kumari, A.,Jha, M.K.,Hait, J.,Kumar, V.,Rajesh Kumar, J.,Lee, J.Y. Korean Society of Industrial and Engineering Chemi 2014 Journal of industrial and engineering chemistry Vol.20 No.4
Systematic scientific studies for dephosphorization and acid leaching of Korean monazite are reported here. 50% NaOH (w/v) solubilizes 99.99% phosphate, at 170<SUP>o</SUP>C, 100g/L pulp density in 4h. Kinetics of phosphate leaching fitted well with model ''chemical reaction control,'' i.e. 1-(1-X)<SUP>½</SUP>=k<SUB>c</SUB>t, E<SUB>a</SUB>=58.04kJ/mol. Further, rare earth hydroxides (REHs) was leached using 6N HCl at 90<SUP>o</SUP>C, 60g/L pulp density for 2h to recover ~95% REMs. Leach liquor generated can be further processed using solvent extraction/ion exchange techniques. From the pure solutions, metal/salts could be obtained using evaporation, precipitation, etc.
Divakar R. Jaiswar,Purnima D. Amin,Durgesh Jha 한국약제학회 2016 Journal of Pharmaceutical Investigation Vol.46 No.7
In the present study aim was to prepare stable solid solution azithromycin dihydrate (AZI) by hot melt extrusion technology (HME). Soluplus and Kollidon VA 64 were selected among polymers based on Hansen solubility parameter calculation in order to prepare amorphous of AZI. Further physicochemical properties of extrudates were characterized by DSC, FTIR, XRD, SEM and contact angle measurement. DSC revealed single broad endothermic peak in extrudates indicated miscibility of AZI into polymeric carriers, which formed monophasic solid system termed as solid solution. XRD confirmed amorphous nature of AZI in extrudates. DSC and XRD suggested molecular dispersion of AZI in polymeric carriers. Amorphous AZI exhibited statistically significant high solubility (P\0.0001) in water in comparison with pure AZI. Solid solution batch AZI 03 showed significant enhancement in solubility (P = 0.0004) in pH 6. The dissolution in dissolution medium pH 6 and water resulted in statistically significant differences (P\0.05) in the percentage amorphous AZI dissolved compared to the percentage AZI dissolved over the period of 60 min. Solid solution formulation showed better wettability than that of pure AZI. Amorphization and increased wettability attributed to solubility and dissolution rate enhancement. Assay and amorphous solid solution characteristics of AZI were found to be stable under accelerated storage condition as per ICH guideline for a period of six months. Therefore, hot melt extrusion technology was suitable method to prepare stable solid solution and dissolution rate enhancement for poorly soluble active like AZI.
Bhamore, Jigna R.,Jha, Sanjay,Singhal, Rakesh Kumar,Park, Tae Jung,Kailasa, Suresh Kumar Elsevier 2018 Journal of molecular liquids Vol.264 No.-
<P><B>Abstract</B></P> <P>In this work, we synthesized fluorescent carbon dots (CDs) using <I>Pyrus pyrifolia</I> (pear) fruit <I>via</I> hydrothermal method at 180 °C for 6 h without using any further treatment or surface passivating agents. The synthesized CDs possess intense blue fluorescence under UV lamp at 365 nm and exhibit emission peak at 471 nm when excited at 390 nm. Because of specific surface functional groups, the synthesized CDs showed high selectivity to detect Al<SUP>3+</SUP> ion through chelation enhanced fluorescence (CHEF) mechanism. The emission peak intensity of CDs at 471 nm was gradually enhanced with increasing concentration of Al<SUP>3+</SUP> ion, thereby Al<SUP>3+</SUP> ion was quantified by plotting calibration curve over the range of 0.005–50 μM with a detection limit of 0.0025 μM (2.5 nM). The nanoprobe was subsequently evaluated by assaying Al<SUP>3+</SUP> ion from spiked water samples, signifying the utility of nanoprobe for assaying of Al<SUP>3+</SUP> ion real samples. Furthermore, we also demonstrate that the bioimaging ability of CDs for imaging of <I>Bacillus subtilis</I> bacterial cell, suggesting that the nanoprobe can be used for cell imaging applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Fluorescent carbon dots are derived from <I>Pyrus pyrifolia</I> (pear) fruit. </LI> <LI> Al<SUP>3+</SUP> ion was detected <I>via</I> chelation enhanced fluorescence mechanism. </LI> <LI> Al<SUP>3+</SUP> ion detection limit is 0.0025 μM (2.5 nM). </LI> <LI> The CDs acted as probes for imaging of <I>Bacillus subtilis</I> bacterial cells. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Schematic representation for fabrication of CDs using pear fruit and sensing of Al<SUP>3+</SUP> ion <I>via</I> chelation enhanced fluorescence mechanism.</P> <P>[DISPLAY OMISSION]</P>
MICROBE-MEDIATED NANOTRANSFORMATION: CADMIUM
ANAL K. JHA,K. PRASAD,A. R. KULKARNI 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2007 NANO Vol.2 No.4
An eco-friendly microbe (lactobacillus sp.)-mediated synthesis of cadmium nanoparticles is reported. The synthesis is performed at room temperature. X-ray and transmission electron microscopy analyses are performed to ascertain the formation of Cd nanoparticles. Individual nanoparticles as well as a number of aggregates almost spherical in shape having a size of 40–60 nm are found.
Bhamore, Jigna R.,Jha, Sanjay,Park, Tae Jung,Kailasa, Suresh Kumar Elsevier 2018 Sensors and actuators. B Chemical Vol.277 No.-
<P><B>Abstract</B></P> <P>In this work, we explored the use of <I>Acacia concinna</I> seeds (shikakai) as a green precursor for the fabrication of ultra-small fluorescent carbon dots (CDs). The synthesized ultra-small fluorescent CDs sense only Cu<SUP>2+</SUP> ion through strong chelation between Cu<SUP>2+</SUP> ion and organic groups of CDs. As a result, highly selective fluorescence “turn-off” probe was developed for assay of Cu<SUP>2+</SUP> ion, causing remarkable fluorescence intensity quenching, which has ability to sense Cu<SUP>2+</SUP> ion even at 0.0043 μM (4.3 nM). Furthermore, the ultra-small fluorescent CDs act as biocompatible probes for multicolour imaging of fungal (<I>Penicillium</I> sp.) cells. The practical application of the developed sensor was demonstrated by assaying of Cu<SUP>2+</SUP> ion in spiked water samples, which confirms their significant analytical and bioanalytical applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Fabrication of fluorescent shikakai CDs from <I>Acacia concinna</I> fruit. </LI> <LI> Shikakai CDs act as fluorescent sensor for Cu<SUP>2+</SUP> ion sensing. </LI> <LI> Shikakai CDs-based fluorescent platform exhibited higher sensitivity. </LI> <LI> Shikakai CDs act as strong chelator to trap Cu<SUP>2+</SUP> ion, shows detection limit of 0.0043 μM. </LI> <LI> Multi-color fungal cell imaging was carried out using shikakai CDs. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Synthesis of fluorescent carbon dots from shikakai for fluorescence detection of Cu<SUP>2+</SUP> ion and fungal cell imaging.</P> <P>[DISPLAY OMISSION]</P>