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- 저자 : ( Irshad Muhammad ) (검색결과 51 건)
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Muhammad Yasir Mehboob,Riaz Hussain,Zobia Irshad,Muhammad Adnan 대한화학회 2021 Bulletin of the Korean Chemical Society Vol.42 No.4
Efficient hole transport materials for solar cell applications are gained huge intension of every scientist. Hole transport materials play a dominant role in solar cells as they provide high power conversion efficiency along with low cost, less toxic, and easy synthesis routs. Motivates from valuable literature, here efforts are being made to designed new novel hole transport materials for solar cell applications. Five new and highly efficient hole transport molecules (BT1–BT5) are designed after end-capped donor modifications of recently synthesized B3 (R) molecule. The photovoltaic, optoelectronic, and structural-property relationship of all designed molecules are extensively studied while using density functional theory and time-dependent density functional theory at MPW1PW91/6-31G(d,p) basis set. Low reorganizational energy of hole is observed in all designed molecules as compared to reference molecule which suggested that designed molecules have high hole mobility as compared to R molecule. Red-shifting in absorption spectrum of designed molecules (as compared to reference molecule) is also seen which offer high power conversion efficiency and high excited highest occupied molecular orbital to lowest unoccupied molecular orbital charge shifting. Low binding and excitation energies are observed in designed molecules. Molecular electrostatic potential, transition density matrix, hole–electron overlap as heat map, open circuit voltage, density of states, and complex study of BT5:PC61BM is also performed for all studied molecule. After all analysis, we believed that our theoretical designed molecules are superior to R molecule, thus we recommend these molecules to experimentalist for future development of highly-efficient solar cells.
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Muhammad Irshad,Bizhu He,Shuang Liu,Sangeeta Mitra,Biswojit Debnath,Min Li,Hafiz Muhammad Rizwan,Dongliang Qiu 한국원예학회 2017 Horticulture, Environment, and Biotechnology Vol.58 No.5
Okra (Abelmoschus esculentus L.) belongs to the Malvaceae family and is a difficult species to manipulateand regenerate in vitro. In this study, factors that influence secretion of phenolic compounds, callus induction, andsubsequent regeneration in okra were optimized. Different concentrations of anti-browning additives, such as activatedcharcoal (AC) and citric acid (CA) were tested alone or in combination with ascorbic acid (AA) in MS medium toevaluate their ability to control phenolic secretion from hypocotyl and cotyledon explants. Among the anti-browningadditives, 200 mg・L-1AC and 10 mg・L-1CA +AA (1:1) were best at controlling phenolic secretion from hypocotyland cotyledon explants in callus induction medium. Hypocotyl explants were more suitable for callus initiation andorganogenesis than cotyledon explants. Moreover, among twelve types of media tested for callus culture, the additionof 0.5 mg・L-12,4-dicholorophenoxy acetic acid (2,4-D) and 1.5 mg・L-1benzyladenine (BA) to the growth media wasthe most effective for hypocotyl explants, whereas MS + 1.5 mg・L-1α-naphthylacetic acid (NAA) and 0.5 mg・L-16-benzyloaminopurine (BAP) was effective for cotyledon explants. Improved shoot regeneration was achieved with 2mg・L-1BAP and 0.1 mg・L-1indole butyric acid (IBA). The maximum number of strong and healthy roots wasobtained on media that included 2 mg・L-1IBA and 200 mg・L-1AC. Rooted plantlets were successfully acclimatizedin earthen pots, and the rooted plantlets had normal morphology and growth characteristics. The present study offersa potential solution for controlling phenolic secretion during okra regeneration using additives and evaluates themanipulation of plant growth regulators for effective regeneration of the Wufu okra cultivar.
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Miniaturized MIMO Antenna with Low Inter-radiator Transmittance and Band Rejection Features
Muhammad Irshad Khan,Muhammad Irfan Khattak,Mauth Al-Hasan 한국전자파학회JEES 2021 Journal of Electromagnetic Engineering and Science Vol.21 No.4
In this article, compact a multiple-input and multiple-output (MIMO) system with flag-shaped radiators and a mountain-shaped ground plane is presented. Isolation is enhanced with the help of a decoupling stub placed between radiators, where two bands are stopped with the help of slits etched into the radiators. The overall size of the proposed antenna is 15 mm × 25 mm × 1.6 mm. The reflection coefficients are less than -10 dB between 3–10.9 GHz, except the bands WiMAX (3.2–3.7 GHz) and WLAN (5–6 GHz); similarly, measured and simulated transmission coefficients are less than -20 dB across the entire band of UWB. The envelope correlation coefficient (ECC) is less than 0.02 and the diversity gain is greater than 9.9 dB. The gain, ECC, radiation pattern, multiplexing efficiency, diversity gain and various other parameters are discussed and evaluated in detail.
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Irshad, Muhammad,Hong, Min Eui,Myint, Aye Aye,Kim, Jaehoon,Sim, Sang Jun De Gruyter 2019 International journal of food engineering Vol.15 No.10
<P><B>Abstract</B></P><P><I>Haematococcus pluvialis</I>(<I>H. pluvialis</I>) can naturally accumulate high amounts of astaxanthin - a powerful antioxidant. However, complete recovery of astaxanthin from the cysts of<I>H. pluvialis</I>is challenging because of the presence of a robust acetolysis resistant cell wall. Herein, a simple and effective planetary ball-milling pretreatment was developed to rupture the cells to attain an almost complete recovery of astaxanthin from<I>H. pluvialis</I>, using a supercritical CO<SUB>2</SUB>and conventional organic solvent-based extraction. An optimized pretreatment using planetary ball mill under very mild conditions (150 rpm, 60 min) allowed the recovery of 31.4 mg/g dry weight of astaxanthin from<I>H. pluvialis</I>, while slightly harsh milling (500 rpm) was found to be detrimental toward astaxanthin. The extracts in acetone exhibited higher antioxidant activity in 1-diphenyl-2-picrylhydrazyl assay than those in dichloromethane. These mild conditions were safe and highly effective for the complete extraction of astaxanthin along with the others extractables. This study opens a new avenue for the efficient recovery of valuable thermolabile ketocarotenoid species from microalgae, which can be applied to the development of economically viable biorefineries.</P>
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Synthesis and characterization of hexagonal ferrite Co2Sr2Fe12O22 with doped polypyrrole composites
Irshad Ali,Abdul Shakoor,M.U. Islam,Muhammad Saeed,Muhammad Naeem Ashiq,M.S. Awan 한국물리학회 2013 Current Applied Physics Vol.13 No.6
Y-type hexagonal ferrite Co2Sr2Fe12O22 was prepared by microemulsion route. A conducting polymer,polypyrrole was chemically synthesized and doped with dodecylbenzenesulphonic acid (PPy$DBSA). FTIR and magnetic properties of Co2Sr2Fe12O22 were investigated and compared with composite made by mixing the Co2Sr2Fe12O22 with this conducting polymer PPyeDBSA by 1:1 molar ratio. Phase analysis was performed by using X-ray diffraction (XRD). The microstructure was examined by scanning electron microscopy (SEM) showing heterogonous distribution of grains. The field dependent magnetic properties of the prepared samples were investigated at room temperature by using vibrating sample magnetometer (VSM). It has been observed that mixing of polymer in ferrite plays a crucial role in enhancing the coercivity, while saturation magnetization (Ms) and remanance were observed to decrease. Due to fine grain size, the density of grain boundaries increases where the domain wall pinning can take place,hence the coercivity of the composite samples increases. Appreciable improved value of coercivity guaranteed the use of these synthesized materials in the recording media, which is ¼1896(Oe) in the present samples. The suitable signal-to-noise ratio in the high density recording media can be achieved due to small particles size of this synthesized composite, which is expected in the present ferriteepolymer composite sample.
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Adsorption of heavy metal ions in ternary systems onto Fe(OH)3
Muhammad Waseem,Syed Mustafa,Muhammad Irshad,Khizar Hussain Shah,Umer Rashid,Wajid Rehman 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.12
The adsorption behavior of amorphous Fe(OH)3 has been studied in multicomponent metal system. The metal ions uptake in the ternary system is lower than in the single system, suggesting that certain sites on the surface of the solid are blocked due to competition. The selectivity trend in the ternary system is observed to be Ni2+>Zn2+>Cd2+ which is, however, lost with increase in the temperature of the aqueous solution. Further, the observed selectivity trend is neither related to electronegativity of the metal ions nor to the pH of the hydrolysis, but has been found dependent on charge to radius ratio. The metal ions adsorption is found to increase with pH, while the converse is true with the rise in temperature. The uptake of metal ions data has been interpreted in terms of stoichiometry, binding constants and adsorption capacities. The negative values of ΔG show that uptake of metal ions is favored at lower temperatures,indicating that the adsorption mechanism essentially remains ion exchange in nature.
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Amna Irshad,Muhammad Hassaan Arshed,H. H. Somaily,Humera Sabeeh,Noor‑ul‑Ain,Imtisal Ayman,Muhammad Farooq Warsi,Imran Shakir 한국고분자학회 2023 Macromolecular Research Vol.31 No.2
The classical co-precipitation technique was carried out for the preparation of cobalt ferrite (CFN), and Ag-doped cobalt ferrite (AgCFN). Composite with graphitic carbon nitride (AgCFN@gCN) was prepared by employing the ultrasonication method. Photocatalytic degradation activity of synthesized materials was evaluated using crystal violet (coloured compound) and benzimidazole (colourless compound) under sunlight. Various physiochemical methods such as UV–Visible, XRD, SEM, and FT-IR spectroscopy were employed for the characterization of prepared samples. XRD was used for structural characterization. The prepared nanomaterials were sized up to be < 09 nm. FT-IR spectroscopy was exploited for the functional group characterization. Surface morphology was perceived through Scanning Electron Microscope. Optical analysis was carried out using a UV–Visible spectrophotometer. The photodegradation efficiencies for crystal violet and benzimidazole were ascertained to be in the order of CFN < AgCFN < AgCFN@gCN, under sunlight. Among the synthesized photocatalysts, AgCFN@gCN was discovered to have the highest photocatalytic degradation efficiency of 52.72% and 84.21% for benzimidazole and crystal violet, respectively. The higher catalytic activity of AgCFN@gCN can be associated with its high surface area and the presence of active sites of the gCN sheets. Role of electrons (e−), holes (h+), and hydroxyl radicals (OH*) in the photocatalytic activity was also assessed.
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Shakoor, Muhammad Bilal,Niazi, Nabeel Khan,Bibi, Irshad,Shahid, Muhammad,Sharif, Fakhra,Bashir, Safdar,Shaheen, Sabry M.,Wang, Hailong,Tsang, Daniel C.W.,Ok, Yong Sik,Rinklebe, Jö,rg Elsevier 2018 The Science of the total environment Vol.645 No.-
<P><B>Abstract</B></P> <P>Contamination of groundwater with toxic arsenic (As) has become an emerging health and environmental problem around the world, which has seen significant attention amongst the scientists for development of new sorbents to remediate As-contaminated water. Here, we explored the arsenate (As(V)) and arsenite (As(III)) sorption to natural water melon rind (WMR), xanthated WMR and citric acid-modified WMR in aqueous solutions, and determined potential of the most potent sorbent for As removal in groundwater. Xanthated WMR (X-WMR) showed relatively higher As(V) and As(III) removal than the citric acid modified WMR (CA-WMR) and natural WMR. The maximum As(III) (99%) and As(V) (98%) removal was obtained at pH 8.2 and 4.6, respectively, by X-WMR at 4 mg L<SUP>−1</SUP> initial As(V) and As(III) concentrations and sorbent dose of 1 g L<SUP>−1</SUP>. Langmuir isotherm model best fitted (<I>R</I> <SUP> <I>2</I> </SUP> of up to 0.96) the data both for As(III) and As(V) sorption to X-WMR. Sorption kinetics of As(V) and As(III) was well described (<I>R</I> <SUP> <I>2</I> </SUP> of up to 0.99) by the pseudo second-order model on surface of the X-WMR. Thermodynamic investigations revealed that As(V) and As(III) sorption was endothermic and spontaneous. The FTIR spectroscopy depicted the presence of different surface function groups (OH, COOH, S-bearing (C=S, S=O and S–S)) which were involved in As(V) and As(III) sequestration on the sorbents examined here. Significantly, X-WMR showed (up to 49%) greater As(III) and As(V) sorption than that of natural WMR. Our results demonstrated that X-WMR efficiently removed 94%–100% (<I>n</I> = 16) of As from As-contaminated drinking well water which possessed detectable concentrations of some anions (e.g., SO<SUB>4</SUB>, CO<SUB>3</SUB>, HCO<SUB>3</SUB>). This study highlights that the X-WMR has potential to remove As, notably As(III), from solutions and drinking water, and might be utilized as a reactive medium for the treatment of As-contaminated water.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Water melon rind (WMR) was tested for arsenic removal potential from water. </LI> <LI> Xanthated WMR removed up to 99% of As(III)/As(V) in solutions. </LI> <LI> Langmuir and pseudo second-order models provided the best fits for As(III) and As(V). </LI> <LI> FTIR spectra showed arsenic sequestration with surface functional groups of sorbents. </LI> <LI> Xanthated WMR successfully removed 94–100% arsenic from drinking well water. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
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