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Nishat Fatima Abdul Khader,Sujatha Dyasanoor 대한암예방학회 2015 Journal of cancer prevention Vol.20 No.3
Background: To assess and compare the salivary flow rate (SFR) and salivary pH among areca nut chewers, oral submucous fibrosis (OSMF) patients and apparently healthy individuals. Methods: A comparative study was conducted to assess and compare the SFR and pH among 135 outpatients (45 areca nut chewers + 45 OSMF + 45 control) at The Oxford Dental College and Research Hospital, Bangalore, India. Subjects were interviewed using structural proforma and Modified Schirmer strips and pH paper were implemented for assessing SFR and pH respectively. Statistical analysis was done using IBM SPSS ver. 21.0 software. Results: A statistically significant increase in SFR (35.7 mm at 3rd minutes) among areca nut group and a decrease in SFR among OSMF group (23.4 mm at 3rd minutes) when compared to apparently healthy subjects (30.7 mm at 3rd minutes). The mean pH among areca nut, OSMF and control groups was 6.76, 6.82, and 6.74 respectively with no statistical significance. Conclusions: The observation and findings of the study clearly showed hypersalivation among areca nut group and hyposalivation among OSMF group, with no significant change in salivary pH when compared to healthy subjects.
Nishat Arshi,Junqing Lu,이찬규,구본흔,Faheem Ahmed 대한금속·재료학회 2013 ELECTRONIC MATERIALS LETTERS Vol.9 No.6
In this work, the effect of deposition power on the structural, morphological, and electrical properties of e-beam evaporated tantalum films was investigated. The as-deposited tantalum films were characterized using x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive x-ray (EDX) and four-point probe resistivity measurements. The XRD patterns revealed the growth of a tetragonal crystalline structure (β-Ta), and the crystallinity of the films increased with increased deposition power. The FESEM images showed that the tantalum film morphology was smooth with fine spherical particles on the surface, and the grain size was found to increase with deposition power. The resistivity of the tantalum films decreased with increased deposition power.
NOVEL AND COST-EFFECTIVE SYNTHESIS OF SILVER NANOCRYSTALS: A GREEN SYNTHESIS
NISHAT ARSHI,FAHEEM AHMED,M. S. ANWAR,SHALENDRA KUMAR,구본흔,여준청,CHAN GYU LEE 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2011 NANO Vol.6 No.4
This paper reports the study on the synthesis and characterization of silver nanocrystals by a two-step synthesis procedure. The first step is the solution-free hand grinding of silver foil and sugar at room temperature for few minutes. The second step is the thermal decomposition of silver/sugar composite to form silver nanocrystals. The as-synthesized silver nanocrystals were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), ultraviolet visible (UV/Vis) spectroscopy, atomic force microscopy (AFM) and transmission electron microscopy (TEM) studies. The XRD pattern showed a face-centered cubic structure (single phase) with high crystallinity. The lattice parameters calculated from XRD pattern were found to be a = 4.12 Å for silver nanocrystals with average grain size of ~ 19 nm. The energy dispersive analysis of X-rays (EDAX) of silver nanocrystals confirmed the presence of silver and no peak of any secondary phase was detected. FESEM and AFM studies showed that the crystals have cube-like morphology. TEM results showed that the size of silver nanocrystals was found to be ~ 22 nm. This novel synthesis route, not reported earlier, would be a promising candidate for a variety of future applications of silver nanocrystals.
AFRL: Adaptive Federated Reinforcement Learning for Intelligent Jamming Defense in FANET
Nishat I Mowla,Nguyen H. Tran,Inshil Doh,Kijoon Chae 한국통신학회 2020 Journal of communications and networks Vol.22 No.3
The flying ad-hoc network (FANET) is a decentralizedcommunication network for the unmanned aerial vehicles (UAVs). Because of the wireless nature and the unique network properties, FANET remains vulnerable to jamming attack with additionalchallenges. First, a decision from a centralized knowledge base isunsuitable because of the communication and power constraintsin FANET. Second, the high mobility and the low density of theUAVs in FANET require constant adaptation to newly exploredspatial environments containing unbalanced data; rendering a distributed jamming detection mechanism inadequate. Third, takingmodel-based jamming defense actions in a newly explored environment, without a precise estimation of the transitional probabilities,is challenging. Therefore, we propose an adaptive federated reinforcement learning-based jamming attack defense strategy. Wedeveloped a model-free Q-learning mechanism with an adaptiveexploration-exploitation epsilon-greedy policy, directed by an ondevice federated jamming detection mechanism. The simulation results revealed that the proposed adaptive federated reinforcementlearning-based defense strategy outperformed the baseline methods by significantly reducing the number of en route jammer location hop counts. The results also showed that the average accuracy of the federated jamming detection mechanism, leveraged inthe defense strategy, was 39.9% higher than that of the distributedmechanism verified with the standard CRAWDAD jamming attackdataset and the ns-3 simulated FANET jamming attack dataset
Comparative study of the Ag/PVP nanocomposites synthesized in water and in ethylene glycol
Arshi, Nishat,Ahmed, Faheem,Kumar, Shalendra,Anwar, M.S.,Koo, Bon Heun,Lee, Chan Gyu Elsevier 2011 Current Applied Physics Vol.11 No.1
<P><B>Abstract</B></P><P>We report direct synthesis of Ag/PVP nanocomposites using PVP (polyvinylpyrrolidone) as a reducing agent. Ag/PVP nanocomposites were synthesized after mixing PVP with acetone and a small amount of aqueous silver nitrate (AgNO<SUB>3</SUB>) under magnetic stirring. The Ag/PVP colloids were then dissolved in water (sample 1) and in ethylene glycol (sample 2) and stirred for 10 days. UV/vis spectra show surface plasmon band in the visible region, centered at wavelengths between 435 and 445nm, a clear consequence of the nano size of dilute Ag particles. TEM results showed that the Ag/PVP nanocomposites have particle sizes ranging from 1 to 6nm and 1 to 12nm for colloids in water and ethylene glycol respectively. Antibacterial activity of these silver nanocomposites as a function of particles concentration against gram-negative bacterium <I>Escherichia coli</I> (<I>E. coli</I>) was carried out in solid growth media. Both the nanocomposites showed good antibacterial activity and caused a growth delay of <I>E. coli</I> with zone of inhibition ∼16mm. There was very little difference between antibacterial activities of two types of silver nanocomposites, though sample 1 with smaller size showed a slightly better antibacterial action.</P> <P><B>Highlights</B></P><P>► Ag nanocomposites were synthesized in water and ethylene glycol with solution chemistry method. ► The Mean diameter was found to be 3.4 and 5.3 nm for water and in ethylene glycol. ► Characteristic absorption peak was found to be 435 and 445 nm in water and ethylene glycol. ► The zone of inhibition for the two types of nanocomposites was almost similar (16 mm). ► Nanocomposites in water with smaller size showed a slightly better antibacterial action.</P>
Interest Point Detection Using Hough Transform and Invariant Patch Feature for Image Retrieval
Ahmad Nishat,안영은,박종안 한국ITS학회 2009 한국ITS학회논문지 Vol.8 No.1
This paper presents a new technique for corner shape based object retrieval from a database. The proposed feature matrix consists of values obtained through a neighborhood operation of detected corners. This results in a significant small size feature matrix compared to the algorithms using color features and thus is computationally very efficient. The corners have been extracted by finding the intersections of the detected lines found using Hough transform. As the affine transformations preserve the co-linearity of points on a line and their intersection properties, the resulting corner features for image retrieval are robust to affine transformations. Furthermore, the corner features are invariant to noise. It is considered that the proposed algorithm will produce good results in combination with other algorithms in a way of incremental verification for similarity.