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Influence of post-annealing on Mn-doped (K0.5Na0.5)NbO3 thin films
Sheeraz Muhammad,Nguyen Bich Thuy,한형수,Bae Jong-Seong,Cho Shinuk,Kim Tae Heon,Ahn Chang Won,김일원 한국물리학회 2022 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.80 No.7
In this work, we synthesized the Mn-doped ( K0.5Na0.5)NbO3 (KNMN) thin films via RF-magnetron sputtering. The effect of the post-annealing temperature on the KNMN film was studied in terms of its structural, ferroelectric, and leakage current properties. We achieved a single perovskite phase in KNMN film. The crystalline quality of the KNMN film was improved further via post-annealing the thin film in the rapid temperature process (RTP), the increase in the intensity of the (100) peak as well as the identification of the additional (200) diffraction peak. The increase in the ferroelectric performance and the reduction in the leakage current density of the post-annealed KNMN film were attributed to the improved crystallinity of the KNMN film. Based on the X-ray photoelectron spectroscopy results, we noticed that the effect of both the chemisorbed layer and the oxygen vacancies was weakened further, thus increasing the crystalline quality of the KNMN film due to post-annealing.
Muhammad Maqsood,Rahmatullah Qureshi,Masroor Ikram,M. Sheeraz Ahmad,Bushra Jabeen,Muhammad Rafique Asi,Junaid Ahmed Khan,Safdar Ali,Lothar Lilge 한국한의학연구원 2018 Integrative Medicine Research Vol.7 No.2
Background: The Pakistani Salt Range has a rich floral diversity including Withania coagulans from the Solanaceae family. Methods: The crude methanolic extracts of the root, leaf, leaf stalk, and fruit of this plant were screened for their cytotoxic activity against human (HeLa, MCF-7, RD) and rat (RG2 and INS-1) cancer cell lines at 20 μg/mL and compared to methotrexate. The IC50 values indicated that leaf stalk and fruit extracts exert an 80% or higher cytotoxic activity against all cell lines at 24 hours. Results: The leaf stalk extract showed the highest cytotoxic efficacy against all tested cell lines, with IC50 values ranging from 0.96 ± 0.01 μg/mL to 4.73 ± 0.05 μg/mL followed by the fruit extract with IC50 values of 0.69 ± 0.01–6.69 ± 0.06 μg/mL after 48–72 hours incubation. The leaf stalk and seed extracts were analyzed for polyphenols and flavonoids using RP-HPLC. The total flavonoid content (TFC) was calculated for all tested samples, and the highest TFC was recorded for the root extract (394.34 ± 1.26 μg/g). The total phenolic content (TPC) was found in the seed extract (307.86 ± 9.42 μg/g) of W. coagulans. The highest contents of myricetin (358.46 ± 2.91 μg/g) were noted in the leaf extract, and highest quercetin was recorded in the seed extract (21.43 ± 0.13 μg/g). The highest gallic acid concentration (83.62 ± 0.71 μg/g) was recorded in leaf stalk extract and p-hydroxybenzoic acid in the seed extract (157.46 ± 1.43 μg/g). Conclusion: The present study gives a scientific insight and comparative analysis of various plant parts in this medicinally important plant species from the Salt Range of Pakistan against both human and rat cancer cells.
Khaliq, Abdul,Sheeraz, Muhammad,Ullah, Aman,Seog, Hae Jin,Ahn, Chang Won,Kim, Tae Heon,Cho, Shinuk,Kim, Ill Won Elsevier 2018 CERAMICS INTERNATIONAL Vol.44 No.11
<P><B>Abstract</B></P> <P>Bi<SUB>0.5</SUB>Na<SUB>0.5</SUB>TiO<SUB>3</SUB>-based piezoelectric ceramics have attracted great interest in actuator applications due to their high strain response; however, high driving field and large hysteresis of these materials are long-lasting obstacles for their commercial applications. Here, we use a strategy to overcome these hurdles by reducing poling field of the relaxor 0.96Bi<SUB>0.5</SUB>(Na<SUB>0.78</SUB>K<SUB>0.22</SUB>)<SUB>0.5</SUB>TiO<SUB>3</SUB>-0.04Bi(Mg<SUB>0.5</SUB>Ti<SUB>0.5</SUB>)O<SUB>3</SUB> (BNKT-0.04BMT) matrix introducing ferroelectric (BNT, BKT and BNKT) seeds (10, 15 and 20 wt%). The poling field decreases with increasing ferroelectric seeds accompanied by the transformation from ergodic relaxor to ferroelectric phase. Consequently, large normalized strains (d<SUP>*</SUP> <SUB>33</SUB> = S<SUB>max</SUB>/E<SUB>max</SUB> = 560, 469 and 450 pm/V) were recorded for BNT (15 wt%), BKT (10 wt%) and BNKT (15 wt%) seeded composites under a reduced driving field of 2.5 kV/mm. These findings indicate that ferroelectric seeds are more effective in reducing the field for strain activation which can be appropriate for actuator devices.</P>
안창원,최진산,Muhammad Sheeraz,김환민,김일원,김태헌 한국물리학회 2021 새물리 Vol.71 No.12
For the last decade, lead-based organic-inorganic halide perovskite materials have provided fertile ground for studying a large variety of intriguing physical properties and for exploring potential applications to novel optoelectronic devices such as photovoltaics, solar cells, light emitting diodes (LED), photo/X-ray detectors, and photocatalysts. Despite a great deal of previous work from the aspect of fundamental science as well as technological applications, the lead-based halide perovskite materials have been limited due to their vulnerability to ambient conditions such as heat, moisture, and ultraviolet (UV) light. We also note that the lead-based halide perovskites incorporate a toxic lead atom, which is harmful to the human body and the environment. Currently, discovering and developing an alternative material to lead-based halide perovskites are of great interest for eco-friendly and sustainable photovoltaic applications. Oxychalcogenide perovskites are promising candidates for emerging photovoltaic materials and are attracting tremendous attention to the associated optoelectronic fields. In this review paper, we will introduce recent reports on the fascinating characteristics of the oxychalcogenide perovskites and significant efforts to overcome the challenges in their synthesis. While taking a look at the current status of the fabrication of oxychalcogenide thin films, we will discuss a pathway to overcome drawbacks both in realizing epitaxial oxychalcogenide thin films with high crystallinity and in developing next-generation photovoltaic devices with multifunctionality.
Khaliq, Abdul,Sheeraz, Muhammad,Ullah, Aman,Lee, Jae Shin,Ahn, Chang Won,Kim, Ill Won Elsevier 2017 Sensors and actuators. A, Physical Vol.258 No.-
<P><B>Abstract</B></P> <P>The fabricated relaxor/ferroelectric composite showed relaxor and/or ferroelectric phase depending upon the weight content of added Bi<SUB>0.5</SUB>Na<SUB>0.5</SUB>TiO<SUB>3</SUB> (BNT) seeds. Bi<SUB>0.5</SUB>Na<SUB>4.5</SUB>Ti<SUB>4</SUB>O<SUB>15</SUB> large particles were processed as precursors and modified to BNT plate-like particles by means of a double molten salt method. The base material 0.96Bi<SUB>0.5</SUB>(Na<SUB>0.78</SUB>K<SUB>0.22</SUB>)<SUB>0.5</SUB>TiO<SUB>3</SUB>-0.04Bi(Mg<SUB>0.5</SUB>Ti<SUB>0.5</SUB>)O<SUB>3</SUB> (BNKT-0.04BMT) was synthesized by means of a solid state reaction technique. The 0-3 type composite of BNKT-0.04BMT powder and BNT seeds was chosen because of the compatibility between their perovskite structures. BNT perovskite seeds were added in 10, 15 and 20wt% proportions to the base BNKT-0.04BMT matrix powder. The highest content of added BNT seeds (20wt%) yielded BNKT-0.04BMT that showed ferroelectric behavior. A large electric field–induced normalized strain (S<SUB>max</SUB>/E<SUB>max</SUB> =560pm/V) was witnessed at the low driving field of 2.5kV/mm for the composition with 15wt% BNT seeds.</P> <P><B>Highlights</B></P> <P> <UL> <LI> BNT seeds were synthesized by molten salt method whereas the BNKT-BMT powder was produced using solid state reaction. </LI> <LI> The BNT seeds were used to fabricate 0–3 type particularized composites of inhomogeneous microstructures. </LI> <LI> It was observed that electric field-induced strain was greatly enhanced under low driving field. </LI> <LI> The relaxor to ferroelectric phase transition was discussed as a function of weight ratios of BNT seeds. </LI> </UL> </P>
Synthesis of Ni-based fluoroperovskites by solvent-free mechanochemical reaction
Choi Jin San,Sheeraz Muhammad,Akram Fazli,Han Hyoung-Su,Lee Jae-Shin,Ahn Chang Won,Kim Tae Heon 한국물리학회 2021 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.79 No.11
We realized fluoride perovskites ANiF3 (A = Na, K, and Ag) incorporating a transition-metal Ni element using solvent-free mechanochemical reaction processes. Methodologically, two different synthetic routes were devised based on the conventional mechanical grinding and the planetary ball milling techniques. The structural characteristics of the as-synthesized fluoroperovskite powders were determined by powder X-ray diffraction measurements and subsequent Rietveld refinement analyses. The band gaps and the chemical compositions of the ANiF3 powders were also examined by ultraviolet–visible absorption measurements and element-specific energy dispersive X-ray spectroscopy, respectively. The goodness of factors of our refinements revealed that the high-energy planetary ball milling was more beneficial than the conventional grinding method in achieving a perovskite ANiF3 phase mechanically. We found that the degree of mechanochemical reaction to form the perovskite phase depended on the crystal structure. With the fitted lattice parameters of the fluoride perovskites, we discussed how a structural modification induced by cation non-stoichiometry affected the stabilization of the fluoroperovskite materials via the mechanochemical synthesis.
Probabilistic Analysis To Analyze Uncertainty Incorporating Copula Theory
Li Bin,Shahzad Muhammad,Munir Hafiz Mudassir,Nawaz Asif,Fahal Nabeel Abdelhadi Mohamed,Khan Muhammad Yousaf Ali,Ahmed Sheeraz 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.1
The emerging trend of distribution generation with existing power system network leads uncertainty factor. To handle this uncertainty, it is a provocation for the power system control, planning, and operation engineers. Although there are numerous techniques to model and evaluate these uncertainties, but in this paper the integration of Copula theory with Improved Latin-hypercube Sampling (ILHS) are incorporated for Probabilistic load Flow (PLF) evaluation. In probabilistic research approaches, the dominant interest is to achieve appropriate modelling of input random variables and reduce the computational burden. To address the said problem, Copula theory is applied to execute the modelling and interaction among input random variables of the active power system network. Considering the real discrete data, the ILHS is adopted. The load fl ow accessibility of the power system is carefully modeled by considering the dependence and uncertainty factors. Modifi ed IEEE 14-bus system is employed to analyze the effi ciency and performance of the proposed model using active power system network. Output power of two wind energy farms situated in New Jersey are obtained for accuracy comparison. The proposed technique shows the superiority in PLF evaluation.