http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Kondalkar, Vijay V.,Mali, Sawanta S.,Mane, Rahul M.,Dandge, P. B.,Choudhury, Sipra,Hong, Chang K.,Patil, Pramod S.,Patil, Shivajirao R.,Kim, Jin H.,Bhosale, Popatrao N. American Chemical Society 2014 INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH - Vol.53 No.47
<P>Nanostructured TiO<SUB>2</SUB> thin films were fabricated via a facile, economical, and energy-efficient microwave-assisted dip-coating (MWDC) technique. Further, the resulting TiO<SUB>2</SUB> films were characterized by means of X-ray diffraction, high-resolution transmission electron microscopy, selected-area electron diffraction, Fourier transform Raman spectroscopy, X-ray photoelectron spectroscopy, and photoluminescence spectroscopy techniques for their phase structure, morphology, and optical and surface properties. TiO<SUB>2</SUB>-mediated photoelectrocatalytic degradation of the antibiotic cefotaxime (CFX) in an aqueous solution was studied by varying the pH under UV illumination. The degradation intermediates and possible reaction degradation path of CFX were analyzed by electrospray ionization time-of-flight mass spectrometry (MS). The MS spectra revealed that degradation of CFX occurs through β-lactum corresponding to the cleavage of the cephem nucleus. Moreover, the antibacterial activity of CFX prior to and after photoelectrocatalytic degradation was carried out to analyze the toxicity against <I>Staphylococcus aureus</I> and salmonella typhi bacteria. Interestingly, it was observed that the antibiotic activity was drastically inhibited after photoelectrocatalytic degradation of the CFX solution. The photoelectrocatalytic stability of a nanostructured TiO<SUB>2</SUB> electrode was evaluated by recycling the degradation experiments. It was observed that there was no significant decrease in the catalytic activity, indicating potential applications of the TiO<SUB>2</SUB> electrode prepared by the MWDC method.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/iecred/2014/iecred.2014.53.issue-47/ie501821a/production/images/medium/ie-2014-01821a_0014.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ie501821a'>ACS Electronic Supporting Info</A></P>
Kondalkar, V. V.,Lee, Y.,Yang, S. S.,Lee, K. Springer Science + Business Media 2017 Journal of materials science Materials in electron Vol.28 No.7
<P>Acoustic-optic (AO) based holographic display unit have been developed through a focused and wide bandwidth surface acoustic wave (SAW). The developed AO device constitutes a laser source, ZnS waveguide layer, Prism, focused and chirp interdigital transducers (IDTs) on 128A degrees YX-LiNbO3 piezoelectric substrate, and a viewing plane. The AO interacted beam's diffraction angle and intensity is modulated by SAW driving power variations of the focused and chirp IDTs. A maximum diffraction efficiency similar to 73 % is obtained at a center frequency of 400 MHz for focused IDTs. By modulating the power of focused IDT, we can shape an incident light into patterns composed of a series of point sources. Our findings provide a facile approach to build hologram display having wide angle light diffraction and high efficiency performance with focused SAW grating.</P>
Kondalkar, Vijay V,Ryu, Geonhee,Lee, Yongbeom,Lee, Keekeun IOP 2018 JOURNAL OF MICROMECHANICS AND MICROENGINEERING - Vol.28 No.7
<P>An acousto-optic (AO) based holographic display unit was developed using surface acoustic wave (SAW) with different wavelength to modulate the diffraction angles, intensities, and phases of light. The new configurations were employed to control two beams simultaneously by using a single chirp inter-digital transducer (IDT), and a micro-lens array was integrated at the end of the waveguide layer to focus the diffracted light on to the screen. Two incident light beams were simultaneously modulated by using different refractive grating periods generated from chirp IDT. A diffraction angle of about 5° was obtained by using a SAW with a frequency of 430 MHz. The increase in the SAW input power enhances the diffraction efficiency of the light beam at the exit. The obtained maximum diffraction efficiency is ~70% at a frequency of 430 MHz. The sloped shape of the waveguide entrance and a tall rounded Ni poles help in coupling the incident light to the waveguide layer. The diffracted beam was collected through the lens, which increased the intensity of light in the viewing plane. COMSOL multi-physics and coupling of mode (COM) modeling were performed to predict the device performance and compared with the experimental results.</P>
Kondalkar, Vijay V.,Mali, Sawanta S.,Kharade, Rohini R.,Khot, Kishorkumar V.,Patil, Pallavi B.,Mane, Rahul M.,Choudhury, Sipra,Patil, Pramod S.,Hong, Chang K.,Kim, Jin H.,Bhosale, Popatrao N. The Royal Society of Chemistry 2015 Dalton Transactions Vol.44 No.6
<P>Herein, we report honeycomb nanostructured single crystalline hexagonal WO<SUB>3</SUB> (h-WO<SUB>3</SUB>) thin films in order to improve electrochromic performance. In the present investigation, honeycomb nanostructured WO<SUB>3</SUB> with different unit size and nanowire array with highly nanocrystalline frameworks have been synthesized <I>via</I> a hydrothermal technique. The influence of hydrothermal reaction time on the honeycomb unit cells, crystallite size, lithium ion diffusion coefficient and switching time for coloration/bleaching were studied systematically. The electrochromic study reveals that the honeycomb unit cell size has a significant impact on the electrochromic performance. Small unit cells in the honeycomb lead to large optical modulation and fast switching response. A large optical modulation in the visible spectral region (60.74% at <I>λ</I> = 630 nm) at a potential of −1.2 V with fast switching time (4.29 s for coloration and 3.38 s for bleaching) and high coloration efficiency (87.23 cm<SUP>2</SUP> C<SUP>−1</SUP>) is observed in the honeycomb WO<SUB>3</SUB> thin films with a unit cell diameter of 1.7 μm. The variation in color on reduction of WO<SUB>3</SUB> with applied potential has been plotted on an <I>xy</I>-chromaticity diagram and the color space coordinate shows the transition from a colorless to deep blue state.</P> <P>Graphic Abstract</P><P>Honeycomb nanostructured single crystalline hexagonal WO<SUB>3</SUB> (h-WO<SUB>3</SUB>) thin films in order to improve electrochromic performance. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c4dt02953d'> </P>
Highly efficient current sensor built on a chip based on nanocrystalline NiFe/Cu/NiFe thin film
Vijay V. Kondalkar,Xiang Li,양상식,이기근 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.53 No.-
We discuss here the realization of a grand vision of a smart GMR device for an on-chip current sensor. The device was characterized to confirm a strong antiferromagnetic coupling and their contribution to giant magnetoresistance. To achieve high sensitivity, we explored different prototypes of device. The GMR sensor is well suited for current sensing as it possesses desired linearity and high sensitivity of 1.32 V Oe1. The result reveals thickness and number of bilayers play an important role in the magnetization to stay aligned to the current channel. This study brings us a step closer to an ideal on-chip current sensor.
임운현(Woonhyun Lim),Vijay Kondalkar,이기근(Keekeun Lee) 대한전기학회 2019 전기학회논문지 Vol.68 No.1
Microheaters with different structures were fabricated and compared to find an optimal configuration enhancing the performances of C₂H₂ gas sensor. Three temperature sensors were integrated on the surface of the insulation layer over the microheater, and resistance changes were observed to check the generated heat from the microheater. A low operating voltage of 1mV was applied to the temperature sensor to minimize any influence of thermal heat from the resistance type temperature sensor, whereas high voltages in the range between 10 and 20V were applied to the microheater. A microheater structure generating maximum heat at low voltage was determined. The generated heat was verified by the temperature sensors on the top of the Si₃N₄ and infrared camera. A long term stability and accuracy of the microheater were observed. The developed microheater was applied to enhance the performances of C₂H₂ gas sensor and successfully confirmed that the developed microheater greatly contributes to the improvement of sensitivity and selectivity of gas sensor.
Development of High Frequency pMUT Based on Sputtered PZT
Un-Hyun Lim,Jin-Hee Yoo,Vijay Kondalkar,Keekeun Lee 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.6
A new type of piezoelectric micromachined ultrasonic transducer (pMUT) with high resonant frequency was developed by using a thin lead zirconate titanate (PZT) as an insulation layer on a floating 10 ㎜ silicon membrane. The PZT insulation layer facilitated acoustic impedance matching at active pMUT, leading to a high performance in the acoustic conversion property compared with the transducer using SiO₂ insulation layer. The fabricated ultrasonic devices were wirelessly measured by connecting two identical acoustic transducers to two separate ports in a single network analyzer simultaneously. The acoustic wave emitted from a transducer induced a 3.16 ㎽ on the other side of the transducer at a distance of 2 ㎝. The transducer performances in terms of device diameters, PZT thickness, annealings, and different DC polings, etc. were investigated. COMSOL simulation was also performed to predict the device performances prior to fabrication. Based on the COMSOL simulation, the device was fabricated and the results were compared.