Surface Wettability of Nitrogen-Doped TiO₂ Films Prepared by Atomic Layer Deposition Using NH₄OH as the Doping Source

Khan, Rizwan,Ko, Kyung Yong,Park, Jong Seo,Kim, Hyungjun,Lee, Han-Bo-Ram American Scientific Publishers 2018 Nanoscience and Nanotechnology Letters Vol.10 No.5

Formation of CeO₂ nanoparticles by solution process for hydrophobic applications

Rizwan Khan,권우혁,이영학,한태희,이한보람 한국진공학회 2017 한국진공학회 학술발표회초록집 Vol.2017 No.8

Improved Optical Transparency of CuO Films Prepared by using Quantum-dot Ink on Glass Substrates

Rizwan Khan,Jin Hyeon Yun,이인환,Mohammad Vaseem,한윤봉 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.68 No.1

The present investigation reports a simple solution process for synthesizing CuO quantum dots at low temperature without using surfactants or templates. Detailed structural characterizations revealed that the as-prepared CuO quantum dots were uniform and dense with high crystallinity. As-prepared CuO quantum dots were used as an ink to prepare CuO films on glass substrates via a spin-coating method. The effects of annealing temperature on the optical properties of CuO films were investigated. The optical transparency of the CuO films showed an improved transmittance of > 80% at a wave length of 800 nm after annealing at 300 C. In addition, the band-gap energy was observed to decrease from 1.70 to 1.28 eV with increasing annealing temperature from 300 to 500 C due to the improvement in the crystallinity with grain growth in the films.

Tetrahydrofuran vapour sensing by electrically conductive silver nanoparticle doped Poly-1-napthylamine-titanium(IV)sulphosalicylophosphate ion exchange nanocomposite

Rizwan Hussain,Mohd Quasim Khan,Asif Ali Khan 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.70 No.-

A novel Poly-1-napthylamine-titanium(IV)sulphosalicylophosphate (PNA-TSP) cation exchange nanocompositewas synthesized by in-situ chemical oxidative polymerization of 1-naphthylamine in thepresence of titanium(IV)sulphosalicylophosphate (TSP) nanoparticles. PNA-TSP doped with silvernanoparticles was synthesized by chemical reduction method. Synthesis of PNA-TSP and Ag/PNA-TSP wasconfirmed by FTIR, FE-SEM, XRD, TGA and EDX characterization techniques. Nanocomposite showedgood ion-exchange capacity (IEC) (2.20 meq g 1) and enhanced DC electrical conductivity from 0.163 S/cm (PNA-TSP) to 0.7112 S/cm (Ag/PNA-TSP). Ag/PNA-TSP nanocomposite based sensor was fabricated forthe detection of tetrahydrofuran vapours over the concentration range from 0.1 M (vapour concentration2.90%) to 0.7 M (vapour concentration 4.24%) tetrahydrofuran solution.

MRAS Based Sensorless Control of a Series-Connected Five-Phase Two-Motor Drive System

Khan, M. Rizwan,Iqbal, Atif The Korean Institute of Electrical Engineers 2008 Journal of Electrical Engineering & Technology Vol.3 No.2

Multi-phase machines can be used in variable speed drives. Their applications include electric ship propulsion, 'more-electric aircraft' and traction applications, electric vehicles, and hybrid electric vehicles. Multi-phase machines enable independent control of a few numbers of machines that are connected in series in a particular manner with their supply being fed from a single voltage source inverter(VSI). The idea was first implemented for a five-phase series-connected two-motor drive system, but is now applicable to any number of phases more than or equal to five-phase. The number of series-connected machines is a function of the phase number of VSI. Theoretical and simulation studies have already been reported for number of multi-phase multi-motor drive configurations of series-connection type. Variable speed induction motor drives without mechanical speed sensors at the motor shaft have the attractions of low cost and high reliability. To replace the sensor, information concerning the rotor speed is extracted from measured stator currents and voltages at motor terminals. Open-loop estimators or closed-loop observers are used for this purpose. They differ with respect to accuracy, robustness, and sensitivity against model parameter variations. This paper analyses operation of an MRAS estimator based sensorless control of a vector controlled series-connected two-motor five-phase drive system with current control in the stationary reference frame. Results, obtained with fixed-voltage, fixed-frequency supply, and hysteresis current control are presented for various operating conditions on the basis of simulation results. The purpose of this paper is to report the first ever simulation results on a sensorless control of a five-phase two-motor series-connected drive system. The operating principle is given followed by a description of the sensorless technique.

Neonatal Intracranial Ischemia and Hemorrhage : Role of Cranial Sonography and CT Scanning

Khan, Imran Ahmad,Wahab, Shagufta,Khan, Rizwan Ahmad,Ullah, Kkram,Ali, Manazir The Korean Neurosurgical Society 2010 Journal of Korean neurosurgical society Vol.47 No.2

Objective : To evaluate the role of cranial sonography and computed tomography in the diagnosis of neonatal intracranial hemorrhage and hypoxic-ischemic injury in an Indian set-up. Methods : The study included 100 neonates who underwent cranial sonography and computed tomography (CT) in the first month of life for suspected intracranial ischemia and hemorrhage. Two observers rated the images for possible intracranial lesions and a kappa statistic for interobserver agreement was calculated. Results : There was no significant difference in the kappa values of CT and ultrasonography (USG) for the diagnosis of germinal matrix hemorrhage/intraventricular hemorrhage (GMH/IVH) and periventricular leucomalacia (PVL) and both showed good interobserver agreement. USG, however detected more cases of GMH/IVH (24 cases) and PVL (19) cases than CT (22 cases and 16 cases of IVH and PVL, respectively). CT had significantly better interobserver agreement for the diagnosis of hypoxic ischemic injury (HII) in term infants and also detected more cases (33) as compared to USG (18). CT also detected 6 cases of extraaxial hemorrhages as compared to 1 detected by USG. Conclusion : USG is better modality for imaging preterm neonates with suspected IVH or PVL. However, USG is unreliable in the imaging of term newborns with suspected HII where CT or magnetic resonance image scan is a better modality.

Area-Selective Atomic Layer Deposition Using Si Precursors as Inhibitors

Khan, Rizwan,Shong, Bonggeun,Ko, Byeong Guk,Lee, Jae Kwang,Lee, Hyunsoo,Park, Jeong Young,Oh, Il-Kwon,Raya, Shimeles Shumi,Hong, Hyun Min,Chung, Kwun-Bum,Luber, Erik J.,Kim, Yoon-Seok,Lee, Chul-Ho,Kim American Chemical Society 2018 Chemistry of materials Vol.30 No.21

<P>Short-chain aminosilanes, namely, bis(<I>N</I>,<I>N</I>-dimethylamino)dimethylsilane (DMADMS) and (<I>N</I>,<I>N</I>-dimethylamino)trimethylsilane (DMATMS), have been used as Si precursors for atomic layer deposition (ALD) of SiO<SUB>2</SUB>. In this work, the DMADMS and DMATMS Si precursors are utilized as inhibitors for area-selective ALD (AS-ALD). The inhibitors selectively adsorb on a SiO<SUB>2</SUB> surface but not on H-Si, so that SiO<SUB>2</SUB> becomes selectively deactivated toward subsequent ALD. The deactivation of the SiO<SUB>2</SUB> surface by the inhibitors was investigated using various experimental and theoretical methods, including surface potential measurements, spectroscopic ellipsometry, and X-ray photoelectron spectroscopy. Better inhibition was observed for ALD of Ru and Pt than for ALD of Al<SUB>2</SUB>O<SUB>3</SUB> and HfO<SUB>2</SUB>. Through quantum mechanical and stochastic simulations, the difference in the blocking ability for noble metal and metal oxide ALD by the aminosilane inhibitors could be attributed to the inherently partial surface coverage by the inhibitors at their saturation and the reactivity of the subsequent ALD precursors. As silane inhibitors can be easily integrated with vacuum-based processes to facilitate high volume manufacturing of upcoming electronic devices, the current study provides a potential approach for the utilization of AS-ALD in pattern fabrication inside 3D nanostructures.</P> [FIG OMISSION]</BR>

Genetic and phenotypic diversity in Solanum lycopersicum genotypes: insights from morpho-molecular and biochemical analyses

Khan Tamana,Rashid Rizwan,Shah Labiba,Afroza Baseerat,Khan Sabba,Bhat Mohd. Ashraf,Alwutayd Khairiah Mubarak,Mahajan Reetika,정용석,Mansoor Sheikh,Sun Hyeon-Jin 한국식물생명공학회 2024 Plant biotechnology reports Vol.18 No.2

Tomato (Solanum lycopersicum L.) crop is well-known for its versatility worldwide and is also recognized as model species used extensively for various genetic studies. The aim of this research was to investigate both inter and intra-genetic diversity present among various tomato genotypes. This investigation was carried out through a comprehensive analysis encompass- ing morphological observations, biochemical assessments, and the utilization of SSR markers. A total of 15 discrete agro- morphological traits and six biochemical traits were undertaken in the current study for evaluating the analysis of variance, genetic parameters and correlation. The analysis of variance indicated significant differences across genotypes for all 15 agro-morphological traits and 6 biochemical traits tested, indicating that the experimental material included considerable vari- ability. Morphological clustering divided the genotypes into 2 clusters and the genotype wise distance matrix was obtained to identify the most diverse genotypes. PCA analysis was conducted to understand the directive relation of traits and magnitude of variability contributed by them. SSR profiling with 24 primers identified 44 alleles with 1.83 as mean number of alleles/ SSR with an average PIC value of 0.31. Structure analysis revealed two sub-populations (K = 2). The AMOVA indicated that 98% of the total variation was present within populations. This study presents a roadmap for composing future breeding strategies for integrating desirable traits in novel tomato lines that combine robustness and nutritive value.

Improved optical transparency of cuo films prepared by using quantum-dot ink on glass substrates

Khan, Rizwan,Yun, Jin Hyeon,Lee, In-Hwan,Vaseem, Mohammad,Hahn, Yoon Bong 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol. No.

<P>The present investigation reports a simple solution process for synthesizing CuO quantum dots at low temperature without using surfactants or templates. Detailed structural characterizations revealed that the as-prepared CuO quantum dots were uniform and dense with high crystallinity. As-prepared CuO quantum dots were used as an ink to prepare CuO films on glass substrates via a spin-coating method. The effects of annealing temperature on the optical properties of CuO films were investigated. The optical transparency of the CuO films showed an improved transmittance of > 80% at a wave length of 800 nm after annealing at 300 A degrees C. In addition, the band-gap energy was observed to decrease from 1.70 to 1.28 eV with increasing annealing temperature from 300 to 500 A degrees C due to the improvement in the crystallinity with grain growth in the films.</P>

MRAS Based Sensorless Control of a Series-Connected Five-Phase Two-Motor Drive System

M. Rizwan Khan,Atif Iqbal 대한전기학회 2008 Journal of Electrical Engineering & Technology Vol.3 No.2

Multi-phase machines can be used in variable speed drives. Their applications include electric ship propulsion, 'more-electric aircraft' and traction applications, electric vehicles, and hybrid electric vehicles. Multi-phase machines enable independent control of a few numbers of machines that are connected in series in a particular manner with their supply being fed from a single voltage source inverter (VSI). The idea was first implemented for a five-phase series-connected two-motor drive system, but is now applicable to any number of phases more than or equal to five-phase. The number of series-connected machines is a function of the phase number of VSI. Theoretical and simulation studies have already been reported for number of multi-phase multi-motor drive configurations of series-connection type. Variable speed induction motor drives without mechanical speed sensors at the motor shaft have the attractions of low cost and high reliability. To replace the sensor, information concerning the rotor speed is extracted from measured stator currents and voltages at motor terminals. Open-loop estimators or closed-loop observers are used for this purpose. They differ with respect to accuracy, robustness, and sensitivity against model parameter variations. This paper analyses operation of an MRAS estimator based sensorless control of a vector controlled series-connected two-motor five￢phase drive system with current control in the stationary reference frame. Results, obtained with fixed￢voltage, fixed-frequency supply, and hysteresis current control are presented for various operating conditions on the basis of simulation results. The purpose of this paper is to report the first ever simulation results on a sensorless control of a five-phase two-motor series-connected drive system. The operating principle is given followed by a description of the sensorless technique.