Promotional effects of K₂O on Ti, Zr and Mn terinary mixed oxides for the selective production of ethylbenzene with CO₂

( Raju ),최광민,이종학,박상언 한국공업화학회 2006 한국공업화학회 연구논문 초록집 Vol.2006 No.-

Analytical Models to Predict Power Harvesting with Piezoelectric Transducer

Raghava Raju Muppala,K. Padma Raju,Nam Mee Moon,Baek Ho Jung 한국전자파학회JEES 2008 Journal of Electromagnetic Engineering and Science Vol.8 No.1

Advances in low power design open the possibility to harvest energy from the environment to power electronic circuits. Electrical energy can be harvested from piezoelectric transducer. Piezoelectric materials can be used as mechanisms to transfer mechanical energy usually vibrating system into electrical energy that can be stored and used to power other devices. Micro- to milli-watts power can be generated from vibrating system. We developed definitive and analytical models to predict the power generated from a cantilever beam attached with piezoelectric transducer. Analytical models are pin-force method, enhanced pin-force method and Euler-Bernoulli method. Harmonic oscillations and random noise will be the two different forcing functions used to drive each system. It has been selected the best model for generating electric power based upon the analytical results obtained.

Intraspecific genetic variation in Corynandra chelidonii (Angiosperms: Cleomaceae) as revealed by SCoT, ISSR and RAPD analyses

Sirangi, Subash,Jogam, Phanikanth,Nemali, Gandhi,Ajmeera, Ragan,Abbagani, Sadanandam,Raju, Vatsavaya S. The Korean Society of Plant Biotechnology 2020 JOURNAL OF PLANT BIOTECHNOLOGY Vol.47 No.4

The genetic diversity of two subpopulations of Corynandra chelidonii, one of terrestrial and the other of aquatic environments, was measured with molecular markers, such as start codon targeted (SCoT), inter simple sequence repeats (ISSR), and random amplification of polymorphic DNA (RAPD). The traditional morphological traits such as habitat, habit, leaf morphology, the colour of the sepals and petals, number of stamens, and seed morphology formed the base for their realization as two varieties, C. chelidonii var. pallae and C. chelidonii var. chelidonii. The polymorphism between the two variants was 100% with the primers SCoT-2 and OPA-1 and 4, while maximum polymorphism was detected with ISSR-2, SCoT-3, and OPA-3. The study used, for the first time, more than one molecular marker to assess the genetic variation underscoring the morphological variation in Corynandra chelidonii (L.f.) Cochrane & Iltis. The study justifies the recognition of the two subpopulations of Corynandra chelidonii from aquatic and terrestrial environments as two distinct varieties, C. chelidonii var. pallae (Reddy & Raju) V.S.Raju and C. chelidonii var. chelidonii, respectively, based on the traditional taxonomic evidence.

Joining of metal-ceramic using reactive air brazing for oxygen transport membrane applications

Raju, K.,Muksin,Kim, S.,Song, K.s.,Yu, J.H.,Yoon, D.H. Elsevier Ltd 2016 Materials & Design Vol.109 No.-

<P>This study examined the joining of dense Ce0.9Gd0.1O2 (-) (delta)-La0.6Sr0.4Co0.2Fe0.8O3 (-) (delta) (GDC-LSCF) ceramics to high temperature metal alloys for the fabrication of multilayered oxygen transport membrane (OTM) stacks. Reactive air brazing using a silver-based paste was performed at 1050 degrees C for 30 min in air to join GDC-LSCF/high temperature alloys, such as AISI 310S, Inconel 600 and Crofer 22 APU. The effects of the various filler materials, including CuO, GDC, LSCF, and GDC-LSCF mixture, in the Ag paste were also examined. The Ag-10 wt% CuO braze filler ensured in a reliable and compact joining without the formation of cracks and voids at the joining interface, while the addition of other ceramic fillers resulted in incomplete joining. Although none of the GDC-LSCF/metal alloy joints showed gas leakage at room temperature, the GDC-LSCF/Crofer joint only maintained the gas-tightness up to 800 degrees C under pressurized air up to 7 bars, which was explained by the microstructural rigidness of the oxide layer formed on the filler/alloy interface at high temperatures. This was supported by the minimal decrease in shear strength of the GDC-LSCF/Crofer joint, which was 91.1 and 88.3 MPa for the as-brazed and isothermally aged joint at 800 degrees C for 24 h in air, respectively. (C) 2016 Published by Elsevier Ltd.</P>

Excitation induced efficient luminescent properties of nanocrystalline Tb³⁺/Sm³⁺:Ca₂Gd₈Si₆O₂₆ phosphors

Raju, G. Seeta Rama,Park, Jin Young,Jung, Hong Chae,Pavitra, E.,Moon, Byung Kee,Jeong, Jung Hyun,Kim, Jung Hwan Royal Society of Chemistry 2011 Journal of materials chemistry Vol.21 No.17

<P>The cathodoluminescence and the excitation induced photoluminescence properties have been investigated for the nanocrystalline Tb<SUP>3+</SUP>/Sm<SUP>3+</SUP>:Ca<SUB>2</SUB>Gd<SUB>8</SUB>Si<SUB>6</SUB>O<SUB>26</SUB> phosphors prepared by a solvothermal reaction method. The XRD patterns confirm their hexagonal structure. The green, orange and white emissions have been obtained by exciting at 275, 378, and 405 nm wavelengths, respectively. The corresponding CIE chromaticity coordinates are found to be in close proximity to the standard points in their respective regions. The cathodoluminescence at low accelerating voltage has also covered the entire visible region, resulting in white emission. These luminescent powders are expected to find potential applications in the development of LEDs and FEDs.</P> <P>Graphic Abstract</P><P>Single-emitting component (Tb<SUP>3+</SUP>/Sm<SUP>3+</SUP>:Ca<SUB>2</SUB>Gd<SUB>8</SUB>Si<SUB>6</SUB>O<SUB>26</SUB> phosphor) produces the white light as well as individual colors at different excitation wavelengths. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c0jm04337k'> </P>

Reactive air brazing of GDC-LSCF ceramics using Ag-10wt% CuO paste for oxygen transport membrane applications

Raju, K.,Muksin,Yoon, D.H. Ceramurgica ; Elsevier Science Ltd 2016 CERAMICS INTERNATIONAL Vol.42 No.14

This paper reports the effectiveness of a Ag-10wt% CuO braze filler for the joining of dense Ce<SUB>0.9</SUB>Gd<SUB>0.1</SUB>O<SUB>2-δ</SUB>-La<SUB>0.6</SUB>Sr<SUB>0.4</SUB>Co<SUB>0.2</SUB>Fe<SUB>0.8</SUB>O<SUB>3-δ</SUB> (GDC-LSCF) dual-phase ceramics for the oxygen transport membrane applications. Brazing was performed at 1050<SUP>o</SUP>C for 30min in air. The microstructure of the ceramic-filler-ceramic interfaces of the polished cross-sectional areas and the elemental distribution were examined. The results indicated that the Ag-10wt% CuO braze filler ensured reliable and compact joining without the formation of cracks and voids at the joining interface. The room temperature mechanical shear strengths were 59.3 and 40.2MPa for the as-brazed and isothermally aged joints at 800<SUP>o</SUP>C for 24h in air, respectively.

Mass spectrometry-based proteome profiling of extracellular vesicles and their roles in cancer biology

Raju Bandu,오재원,김광표 생화학분자생물학회 2019 Experimental and molecular medicine Vol.51 No.-

Over the past three decades, extracellular vesicles (EVs) have arisen as important mediators of intercellular communication that are involved in the transmission of biological signals between cells to regulate various biological processes. EVs are largely responsible for intercellular communication through the delivery of bioactive molecules, such as proteins, messenger RNAs (mRNAs), microRNAs (miRNAs), DNAs, lipids, and metabolites. EVs released from cancer cells play a significant role in signal transduction between cancer cells and the surrounding cells, which contributes to the formation of tumors and metastasis in the tumor microenvironment. In addition, EVs released from cancer cells migrate to blood vessels and flow into various biological fluids, including blood and urine. EVs and EVloaded functional cargoes, including proteins and miRNAs, found in these biological fluids are important biomarkers for cancer diagnosis. Therefore, EV proteomics greatly contributes to the understanding of carcinogenesis and tumor progression and is critical for the development of biomarkers for the early diagnosis of cancer. To explore the potential use of EVs as a gateway to understanding cancer biology and to develop cancer biomarkers, we discuss the mass spectrometric identification and characterization of EV proteins from different cancers. Information provided in this review may help in understanding recent progress regarding EV biology and the potential roles of EVs as new noninvasive biomarkers and therapeutic targets.

Sintering additives for SiC based on the reactivity: A review

Raju, Kati,Yoon, Dang-Hyok Elsevier 2016 CERAMICS INTERNATIONAL Vol.42 No.16

<P><B>Abstract</B></P> <P>Silicon carbide (SiC) is one of the most attractive materials for high temperature applications, being used in many areas, such as gas turbines, heat exchangers, and space shuttles, because of its excellent strength, oxidation resistance and chemical stability at high temperatures. Moreover, SiC and its composites are being considered as structural materials for advanced fission reactors and future fusion reactors owing to its additional low induced radioactivity under neutron irradiation conditions. On the other hand, pure SiC can only be densified by sintering at high temperatures and pressures because of its high covalent bonding nature and low self-diffusivity. Therefore, the addition of sintering additives is essential for enhancing the densification of SiC. This paper reviews the criteria for the selection of effective SiC sintering additives based on the Gibbs free energy to predict the reactivity between the sintering additive and SiC, particularly for liquid phase sintering at 1700–1900°C. The thermodynamic simulation was verified by offering the experimental results for various types of sintering additives, such as main group metals, metal oxides, and rare earth elements. This review suggests a guideline for the selection of sintering additives for SiC.</P>

Enhanced green upconversion luminescence properties of Er³⁺/Yb³⁺ co-doped strontium gadolinium silicate oxyapatite phosphor

Raju, G. Seeta Rama,Pavitra, E.,Bharat, L. Krishna,Rao, Gattupalli Manikya,Jeon, Tae-Joon,Huh, Yun Suk,Han, Young-Kyu Elsevier 2018 CERAMICS INTERNATIONAL Vol.44 No.12

<P><B>Abstract</B></P> <P>Upconversion Sr<SUB>2</SUB>(Gd<SUB>.98-<I>x</I> </SUB>Er<SUB>.02</SUB>Yb<SUB> <I>x</I> </SUB>)<SUB>8</SUB>Si<SUB>6</SUB>O<SUB>26</SUB> (SGSO:2Er<SUP>3+</SUP>/<I>x</I>Yb<SUP>3+</SUP>) phosphor materials were synthesized using a citrate sol-gel process. X-ray diffraction patterns confirmed their hexagonal structure. Field emission scanning electron microscopy images of SGSO:2Er<SUP>3+</SUP>/<I>x</I>Yb<SUP>3+</SUP> phosphors depicted submicron particles. The enhanced upconversion luminescence properties of SGSO:2Er<SUP>3+</SUP>/<I>x</I>Yb<SUP>3+</SUP> phosphors were analysed as a function of Yb<SUP>3+</SUP> ion concentration and laser power. The energy transfer induced enhanced emission of the Er<SUP>3+</SUP>/ Yb<SUP>3+</SUP> ions co-doped SGSO phosphors was ascribed to multi-phonon relaxation. The calculated chromaticity coordinates of the SGSO:2Er<SUP>3+</SUP>/<I>x</I>Yb<SUP>3+</SUP> phosphors showed emissions could be tuned by changing Yb<SUP>3+</SUP> ion concentration. Optimized sample exhibited the chromaticity coordinate values near to the ultra-high definition television standard green emission coordinates.</P>

Stereoselective Recognition of Amino Alcohols and Amino Acids by Carbonylurea- and Carbonyguanidinium-based Imine Receptors

Raju Nandhakumar,Yun Soo Ahn,Hoe-Jin Yoon,김관묵 대한화학회 2009 Bulletin of the Korean Chemical Society Vol.30 No.12

New receptors 1-3 that bind stereoselectively amino alcohols and convert chirality of amino acidsvia imine bond formation were synthesized. The receptors have uryl (1), thiouryl (2) and guanidinium (3) groups all with additional phenylcarbonyl motifs, which are effective hydrogen bonding donors and play a key role in the stereoselective recognitions. The stereoselectivities were measured from the integration of 1H NMR peaks. Compound 1 and 2 showed the stereoselectivities for the imine formation with amino alcohols (KR/KS) in the range of 2 ~ 4, and compound 3 in the range of 4 ~ 8. Chirality conversion efficienciesof 1-3 for amino acids, i.e. D/L ratio at equilibrium, are in the range of 1.5 ~ 5.6, showing a little higher efficiency with 3. The additional phenylcarbonyl motifs in 1-3 were revealed not to contribute to significant enhancement of the selectivities.