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Chinese Physics B 2013年第7期22卷 339-345页

作者： T. akhter m. m. Hossain A. A. mamun Department of Physics Jahangirnagar University Department of Electrical and Electronic Engineering Bangladesh University of Business and Technology

A precise theoretical investigation has been made on the cylindrical and spherical （nonplanar） Gardner solitons （GSs） and double layers （DLs） in a dusty electronegative plasma （composed of inertial positive and negative ions, maxwellian cold electrons, non-thermal hot electrons, and negatively charged static dust）. The reductive perturbation method has been used in derivation of the modified Gardner （mG） equation describing the nonlinear propagation of the dust ion-acoustic （DIA） waves. The mG equation admits solitary waves （SWs） and DLs solutions for σ around its critical value σ c （where σc is the value of σ corresponding to the vanishing of the nonlinear coefficient of the Korteweg de-Vries （K-dV） equation）. The nonplanar SWs and DLs solutions are numerically analyzed and the parametric regimes for the existence of the positive as well as negative SWs and negative DLs are obtained. The basic features of nonplanar DIA SWs and DLs, which are found to be different from planar ones, are also identified. The implications of our results to different space and laboratory dusty plasma situations, are discussed.

关键词： electronegative plasma two-temperature electrons Garner solitons double layers

Synthesis and Characterization of Fe_(50)Cr_(14)mo_(14)C_(14)B_6Gd_2 Bulk Amorphous Steel

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Journal of materials Science & Technology 2010年第9期26卷 783-786页

作者： m. Iqbal J.I. akhter H.F. Zhang Z.Q. Hu Physics Division Pakistan Institute of Nuclear Science &: Technology P.O. Nilore Islamabad Pakistan Shenyang National Laboratory for materials Science Institute of Metal Research Chinese Academy of SciencesShenyang 110016 China

Bulk amorphous steel having 7 mm thickness was synthesized to evaluate its thermal stability and mechanical *** steel was synthesized by Cu mold casting technique using 1-2N pure *** of the material was done by X-ray diffraction,differential scanning calorimetry and scanning electron *** activation energies were calculated by Kissinger equation and it was found that the steel had better stability against *** properties like Vicker s hardness,nanohardness,elastic modulus and elastic recovery of as-cast and annealed samples were *** was concluded that the present steel had good glass-forming ability（GFA） and mechanical properties.

关键词： Bulk amorphous steels Activation energy Glass-forming ability mechanical properties

Contributions of shortwave radiation to the formation of temperature inversions in the Bay of Bengal and eastern equatorial Indian Ocean:A modeling approach

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Acta Oceanologica Sinica 2022年第9期41卷 19-37页

作者： K m Azam Chowdhury Wensheng Jiang Changwei Bian Guimei Liu md Kawser Ahmed Shaila akhter College of Oceanic and Atmospheric Sciences Ocean University of ChinaQingdao266100China Department of Oceanography&International Centre for Ocean Governance(ICOG) University of DhakaDhaka1000Bangladesh National marine Environmental Forecasting Center Beijing100081China Key Lab of marine Environment and Ecology of ministry of Education Ocean University of ChinaQingdao266100China Frontiers Science Center for Deep Ocean multispheres and Earth System(FDOmES) Ocean University of ChinaQingdao266100China Pilot National Laboratory for marine Science and Technology(Qingdao) Qingdao266237China Bangladesh Betar Ministry of Information and BroadcastingGovernment of the People’s Republic of BangladeshDhaka1207Bangladesh

Variations in incoming shortwave radiation influence the net surface heat flux,contributing to the formation of a temperature *** effects of shortwave radiation on the temperature inversions in the Bay of Bengal and eastern equatorial Indian Ocean have never been ***,a high-resolution(horizontal resolution of 0.07°×0.07° with 50 vertical layers) Regional Ocean modeling System(ROmS) model is utilized to quantify the contributions of shortwave radiation to the temperature inversions in the study *** of the mixed layer heat and salt budgets are performed,and different model simulations are *** model results suggest that a 30% change in shortwave radiation can change approximately 3% of the temperature inversion area in the Bay of *** shortwave radiation reduces the net surface heat flux and cools the mixed layer substantially;it also reduces the evaporation rate,causing less evaporative water vapor losses from the ocean than the typical situation,and ultimately enhances haline ***,the rudimentary outcome of this research is that a decrease in shortwave radiation produces more temperature inversion in the study region,which is primarily driven by the net surface cooling and supported by the intensive haline ***,low shortwave radiation eventually intensifies the temperature inversion layer by thickening the barrier *** study could be an important reference for predicting how the Indian Ocean climate will respond to future changes in shortwave radiation.

关键词： mixed layer cooling haline stratification temperature inversion ROmS model shortwave radiation Bay of Bengal eastern equatorial Indian Ocean

Hepatocytes isolated from neoplastic liver-immunomagnetic purging as a new source for transplantation

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World Journal of Gastroenterology 2008年第32期14卷 5025-5031页

作者： Aravin Gunasegaram Javed akhter Peng Yao Loreena A Johnson Stephen m Riodan David L morris University of New South Wales Department of Surgery St George Hospital Sydney 2044 Australia Gastrointestinal and Liver Unit Prince of Wales Hospital University of New South Wales Sydney 2044 Australia

AIm： To investigate whether hepatocytes isolated from macroscopically normal liver during hepatic resection for neoplasia could provide a novel source of healthy hepatocytes, including the development of reliable protocols for malignant cells removal from the hepatocyte preparation. mETHODS： Hepatocytes were procured from resected liver of 18 patients with liver tumors using optimised digestion and cell-enrichment protocols. Suspensions of various known quantities of the HT-29 tumor cell line and patient hepatocytes were treated or not with Ep-CAm-antibody-coated immunomagnetic beads in order to investigate the efficacy of tumor-purging by immunomagnetic depletion, using a semi-quantitative RT-PCR method developed to detect tumor cells. Immunomagnetic bead-treated or bead-untreated tumor cell-hepatocyte suspensions were transplanted intra-peritoneally in Balb/C nude mice to assess the rates of tumor development. RESULTS： mean viable hepatocyte yield was 9.3×10^6 cells per gram of digested liver with mean viability of 70.5%. Immunomagnetic depletion removed tumor cells to below the RT-PCR detection-threshold of 1 tumor cell in 10^6 hepatocytes, representing a maximum tumor purging efficacy of greater than 400000-fold. Transplanted, immunomagnetic bead-purged tumor cell-hepatocyte suspensions did not form peritoneal tumors in Balb/C nude mice. Co-transplantation of hepatocytes with tumor cells did not increase tumorigenesis of the tumor cells. CONCLUSION： Immunomagnetic depletion appears to be an effective method of purging contaminating tumor cells to below threshold for likely tumorigenesis. Along with improved techniques for isolation of large numbers of viable hepatocytes, normal liver resected for neoplasia has potential as another clinically useful source of hepatocytes for transplantation.

关键词： Hepatocyte transplantation Immuno-magnetic purging Isolation of hepatocytes

Antibacterial Characterization of Silver Nanoparticles against *** ATCC-15224

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Journal of materials Science & Technology 2008年第2期24卷 192-196页

作者： m.Raffi F.Hussain T.m.Bhatti J.I.akhter A.Hameed m.m.Hasan Department of Chemical and materials Engineering Pakistan Institute of Engineering and Applied Sciences(PIEAS)Islamabad-45650Pakistan Department of microbiology Faculty of Biological SciencesQuaid-i-Azam UniversityIslamabadPakistan Central Analytical Facility Division Pakistan Institute of Nuclear Science and Technology(PINSTECH)Islamabad-45650Pakistan Physics Division Pakistan Institute of Nuclear Science and Technology(PINSTECH)Islamabad-45650Pakistan

Silver nanoparticles of mean size 16 nm were synthesized by inert gas condensation （IGC） method. Crystalline structure, morphology and nanoparticles size estimation were conducted by X-ray diffraction （XRD） and transmission electron microscopy （TEm）. Antibacterial activity of these silver nanoparticles as a function of particles concentration against gram-negative bacterium Escherichia coli （E. coli） was carried out in liquid as well as solid growth media. Scanning electron microscopy （SEm） and TEm studies showed that silver nanoparticles after interaction with *** have adhered to and penetrated into the bacterial cells. Antibacterial properties of silver nanoparticles are attributed to their total surface area, as a larger surface to volume ratio of nanoparticles provides more efficient means for enhanced antibacterial activity.

关键词： Silver Nanoparticles Antibacterial Electron microscopy

Effect of minor Alloying on Crystallization Behavior and Thermal Properties of Zr_(64.5)Ni_(15.5)Al_(11.5)Cu_(8.5) Bulk Amorphous Alloy

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Journal of materials Science & Technology 2011年第6期27卷 534-538页

作者： muhammad Iqbal Javed Iqbal akhter Haifeng Zhang Zhuangqi Hu microstructuralStudies Group Physics Division Pakistan Institute of Nuclear Science and Technology (PINSTECH) P.O. Nilore Islamabad Pakistan Shenyang Nationel Laboratory for materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China

minor alloying plays an important role in the synthesis and improvement of thermal stability of bulk metallic glasses（BmGs）.The present study was conducted to investigate the effect of minor additions of Y,Ti and Nb on the crystallization behavior and the thermal properties of Zr64.5Ni15.5Al11.5Cu8.5 *** parameters and the activation energies for crystallization were calculated for four（Zr0.645Ni0.155Al0.115-Cu0.085）100-xmx（m=Y,Ti and Nb,while x=0,2 at.） *** present alloys have wide supercooled liquid region of ≥87 *** activation energy was found to be greater than 300 kJ/mol for the base *** crystalline phases were identified in the samples annealed at 823 K for 20 *** glass transition temperature（Trg） and other thermal parameters such as γ,δ and β were improved by Y and Ti *** addition resists crystallization below annealing temperature 713 K,however,its effect on thermal properties is not very promising.

关键词： Activation energy Thermal properties Glass-forming ability Thermal stability Precipitation microstructure

Crystallization and Hardness of melt Spun Fe_(73)Si_(13)B_9Nb_4Cu_1 Alloy

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Journal of materials Science & Technology 2009年第1期25卷 48-52页

作者： J.I. akhter m. Iqbal m. Siddique m. Ahmad m.A. Haq m.A. Shaikh Z.Q. Hu Physics Division Pakistan Institute of Nuclear Science and Technology P. O. Nilore Islamabad Pakistan Shenyang National Laboratory for materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China Department of Chemical and materials Engineering Pakistan Institute of Engineering and Applied Sciences P.O. Nilore Islamabad Pakistan

An alloy having composition Fe73Si13B9Nb4Cu1 was synthesized by melt spinning to investigate the kinetics of crystallization. Techniques of differential scanning calorimetry （DSC）, X-ray diffraction （XRD） and mossbauer spectroscopy were employed to characterize the phases produced due to annealing at various temperatures. High temperature DSC revealed two stage crystallization reactions. First stage, crystallization occurs at temperature around 514℃ with the production of α-Fe （bcc） and Fe3Si phases. In the second stage, Fe2B and α-Fe （Si,Nb） phases were produced. mossbauer results revealed the formation of Fe3Si, Fe13Si3 and Fe7Si1 in the first stage and Fe3Si, Fe13Si3, Fe2B and α-Fe （Si,Nb） phases in the second stage of crystallization. An abrupt change in average internal magnetic field was observed at 500℃. The maximum hardness value was found for the sample heat-treated at 500℃.

关键词： Amorphous alloy Crystallization mossbauer spectroscopy Hardness

A monodisperse-aerosol generation system： Design, fabrication and performance

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Particuology 2017年第5期15卷 118-125页

作者： Amit md. Estiaque Arefin m.H. masud mohammad U.H. Joardder md. Shamim akhter Department of mechanical Engineering Rajshahi University of Engineering and Technology Rajshahi Bangladesh

monodisperse aerosols are essential in many applications, such as filter testing, aerosol instrument calibration, and experiments for validating models. This paper describes the design principle, construction, and performance of a monodisperse-aerosol generation system that comprises an atomizer, virtual impactor, microcontroller-based isokinetic probe, wind tunnel, and velocity measurement device. The size distribution of the produced monodisperse aerosols was determined by an optical particle counter. The effects of atomizer characteristics, the rates of minor and major flow, and solution criteria were investigated. It was found that all these parameters affect the generation of monodisperse aerosol. Finally, the expected geometric standard deviation （〈1.25） of monodisperse aerosol particles was obtained with the most suitable atomizer for 10% oleic acid in ethyl alcohol solution with 5%-15% minor flow, where the ratio between the nozzle-to-probe distance and acceleration-nozzle-exit diameter was 0.66. The con- structed monodisperse-aerosol-generation system can be used for instrumental calibration and aerosol research.

关键词： Aerosol generation monodisperse Design Sampling Counting

A Secured message Transmission Protocol for Vehicular Ad Hoc Networks

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Computers, materials & Continua 2021年第7期68卷 229-246页

作者： A.F.m.Suaib akhter A.F.m.Shahen Shah mohiuddin Ahmed Nour moustafa UnalÇavu¸soglu Ahmet Zengin Department of Computer Engineering Sakarya UniversitySakarya54050Turkey Department of Electrical and Electronics Engineering Istanbul Gelisim UniversityIstanbulTurkey School of Science Edith Cowan UniversityPerthWA6027Australia School of Engineering and Information Technology UNSWCanberra BC2610Australia

Vehicular Ad hoc Networks(VANETs)become a very crucial addition in the Intelligent Transportation System(ITS).It is challenging for a VANET system to provide security services and parallelly maintain high throughput by utilizing limited *** overcome these challenges,we propose a blockchain-based Secured Cluster-based mAC(SCB-mAC)*** nearby vehicles heading towards the same direction will form a cluster and each of the clusters has its blockchain to store and distribute the safety *** message which contains emergency information and requires Strict Delay Requirement(SDR)for transmission are called safety messages(Sm).Cluster members(Cms)sign Sms with their private keys while sending them to the blockchain to confirm authentication,integrity,and confidentiality of the message.A Certificate Authority(CA)is responsible for physical verification,key generation,and privacy preservation of the *** implemented a test scenario as proof of concept and tested the safety message transmission(SmT)protocol in a real-world *** and storage overhead analysis shows that the proposed protocol for SmT implements security,authentication,integrity,robustness,non-repudiation,*** maintaining the *** that are less important compared to the Sms are called non-safety messages(NSm)and vehicles use RTS/CTS mechanism for NSm *** studies show that the proposed NSm transmission method maintains 6 times more throughput,2 times less delay and 125%less Packet Dropping Rate(PDR)than traditional mAC *** results prove that the proposed protocol outperforms the traditional mAC protocols.

关键词： Ad hoc networks data security digital signatures distributed storage intelligent vehicles vehicular ad hoc networks wireless communication

Performance of Islamic and conventional stock indices:empirical evidence from an emerging economy

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Financial Innovation 2015年第1期1卷 229-245页

作者： md Ejaz Rana Waheed akhter Center of Islamic Finance Department of Management SciencesCOMSATS Institute of Information TechnologyLahorePakistan

Background:This study aims to investigate the extent to which the conditional volatilities of both Shari’ah compliant stock and conventional stock are related to those of interest rate and exchange rate in the emerging economy of ***:We used KmI 30 and KSE 100 indices for Islamic and conventional stock for the period of July 2008 to November *** employed Generalized Autoregressive Conditional Heteroskedastic in the mean(GARCH-m)*** framework relaxes constancy assumption of classical linear regression(CLRm)model and allows exchange rate and interest rate volatility to evolve over *** GARCHm framework also reveals results about risk-return trade-off in the context of both Islamic and conventional stock ***:The findings show positive and statistically significant effect of interest rate volatility on KSE-100,whereas KmI-30 remains unaffected by the *** rate volatility is found to be significant for both conventional and Islamic *** relationship of risk coefficient(γ)and stocks returns,as expected,is positive and statistically significant for both KmI-30 and *** result is consistent with the theory of risk-return *** results of parametric t-test show significant difference between returns of both *** implies that Shari’ah compliant stock index(KmI-30)of Pakistan underperforms its conventional ***:By using different performance measures(Sharp ratio,Jensen alpha,Treynor ratio),this study also investigates the hypothesis that Islamic stock index has inferior performance compared with unscreened conventional counterparts due to availability of a smaller investment universe,increased monitoring costs,and limited diversification.

关键词： KmI-30 KSE-100 Index Shari’ah Exchange rate volatility Interest rate volatility Stock Performance etc