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Chinese Physics Letters 2016年第1期33卷 132-135页

作者： md.Ghulam Saber Rakibul Hasan Sagor md.Ruhul Amin Department of Electrical and Electronic Engineering Islamic University of Technology

The linear dispersion relation of a trapezoidally corrugated slow wave structure （TCSWS） is analyzed and presented. The size parameters of the TCSWS are chosen in such a way that they operate in the x-band frequency range. The dispersion relation is solved by utilizing the Rayleigh-Fourier method by expressing the radial function in terms of the Fourier series. A highly accurate synthetic technique is also applied to determine the complete dispersion characteristics from experimentally measured resonances （cold test）. Periodic structures resonate at specific frequencies when the terminals are shorted numerical calculation, synthetic technique and cold appropriately. The dispersion characteristics obtained from test are compared, and an excellent agreement is achieved.

关键词： of on A Comparative Study of Dispersion Characteristics Determination of a Trapezoidally Corrugated Slow Wave Structure Using Different Techniques in been is

Proton conductivity performance and its correlation with physiochemical properties of proton exchange membrane(PEM)

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Chinese Journal of Chemical Engineering 2024年第10期74卷 100-116页

作者： Mirza Nusrat Sweety md Abdus Salam Hydrogen Energy Laboratory Bangladesh Council of Scientific and Industrial Research(BCSIR)Chattogram 4220Bangladesh Institute of Mining Mineralogy and Metallurgy(IMMM)BCSIRJoypurhat 5900Bangladesh BCSIR Dhaka Laboratories Dhaka 1205Bangladesh

Graphene oxide(GO)filler containing diversified Nafion-based proton exchange membrane(PEM)is studied to know the unique physical and chemical properties and performances of ***-SPEEK 1%-GO 0.75%(NSG-0.75%)composite shows the highest proton conductivity of 0.327 S·cm^(-1) at 90℃ and 100%RH(relative humidity)among all the PEM *** descending order of significant proton conductivity is found as;Nafion-sPGO(1%)0.306 S·cm^(-1)>Nafion/ZIF-8@GO 0.280 S·cm^(-1)>Nafion/PGO(2%)0.277 S·cm^(-1)>Nafion/GO-sulfur(3%)0.232 S·cm^(-1)>Nafion/GO-poly-SPM-co-PEGMEMA(1%)0.229 S·cm^(-1)>Nafion/Ce-sPGO(1%)0.215 S·cm^(-1).The proton conductivity,water uptake capacity and ion exchange capacity,hydration number,thermal and oxidative stability,mechanical integrity(tensile strength),maximum power,and current density are found to be increased while activation energy and fuel crossover show a decrement as GO or modified GO is incorporated in the Nafion *** component analysis(PCA)predicted a significant correlation between the proton conductivity and the properties;the water uptake capacity,ion exchange capacity,hydration number,maximum power density,and maximum current density are 0.598%,0.688%,0.894%,0.980%,and 0.852%accordingly.A multiple linear model equation of proton conductivity is defined with the parameters of water uptake capacity,ion exchange capacity,hydration number,maximum power density,and maximum current density whereas the regression coefficient is 0.9923.

关键词： Fuel cells Membranes Nafion GO-filler Proton conductivity Principal component analysis

Artifact suppression and analysis of brain activities with electroencephalography signals

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Neural Regeneration Research 2013年第16期8卷 1500-1513页

作者： md. Rashed-Al-Mahfuz md. Rabiul Islam Keikichi Hirose md. Khademul Islam Molla Department of Computer Science and Engineering Pabna University of Science and Technology Department of Information and Communication Engineering The University of Tokyo Department of Computer Science and Engineering Rajshahi University

Brain-computer interface is a communication system that connects the brain with computer （or other devices） but is not dependent on the normal output of the brain （i.e., peripheral nerve and muscle）. Electro-oculogram is a dominant artifact which has a significant negative influence on further analysis of real electroencephalography data. This paper presented a data adaptive technique for artifact suppression and brain wave extraction from electroencephalography signals to detect regional brain activities. Empirical mode decomposition based adaptive thresholding approach was employed here to suppress the electro-oculogram artifact. Fractional Gaussian noise was used to determine the threshold level derived from the analysis data without any training. The purified electroencephalography signal was composed of the brain waves also called rhythmic components which represent the brain activities. The rhythmic components were extracted from each electroencephalography channel using adaptive wiener filter with the original scale. The regional brain activities were mapped on the basis of the spatial distribution of rhythmic components, and the results showed that different regions of the brain are activated in response to different stimuli. This research analyzed the activities of a single rhythmic component, alpha with respect to different motor imaginations. The experimental results showed that the proposed method is very efficient in artifact suppression and identifying individual motor imagery based on the activities of alpha component.

关键词： neural regeneration brain activity brain waves data adaptive filtering electroencephalography electro-oculogram artifact topographic mapping Wiener filtering neuroregeneration

Stature estimation from footprint measurements in Bangladeshi adults

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Forensic Sciences Research 2022年第2期7卷 124-131页

作者： md Asadujjaman md Harun Or Rashid md Sohel Rana md Mosharraf Hossain Department of Industrial&Production Engineering Rajshahi University of Engineering&TechnologyRajshahiBangladesh

The estimation of stature is very important in forensic investigation,as it provides useful data that can narrow the pool of potentially matching *** purpose of this study was to develop formulae for the estimation of stature from footprint measurements in Bangladeshi *** study included 118 randomly selected men and 130 randomly selected women,all aged 18–50 *** each participant,stature and six footprint measurements were taken by means of standard measurement *** measurements were found to be positively correlated with *** was estimated by using linear regression *** right T1 length in men(R:þ0.587,R^(2):0.345)and the right T2 length in women(R:þ0.506,R^(2):0.256)were the most reliable individual estimators of ***,when data were combined for both sexes,the right T2 length was identified as the most reliable estimator of stature,with higher values of R(þ0.792)and R^(2)(0.627).In conclusion,human stature can be successfully estimated by using footprint measurements;this finding can be applied in forensic research and investigation.

关键词： Forensic sciences forensic anthropology anthropometry footprint stature estimation forensic identification

Variability in total antioxidant capacity, antioxidant leaf pigments and foliage yield of vegetable amaranth

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Journal of Integrative Agriculture 2018年第5期17卷 1145-1153页

作者： Umakanta Sarker md Tofazzal Islam md Golam Rabbani Shinya Oba Department of Genetics and Plant Breeding Faculty of AgricultureBangabandhu Sheikh Mujibur Rahman Agricultural University Laboratory of Field Science Faculty of Applied Biological ScienceGifu University Department of Biotechnology Faculty of AgricultureBangabandhu Sheikh Mujibur Rahman Agricultural University Department of Horticulture Faculty of AgricultureBangladesh Agricultural University

Twenty vegetable amaranth genotypes were evaluated for total antioxidant capacity, antioxidant leaf pigments, vitamins, and selection of suitable genotypes for extraction of juice in a randomized complete block design（RCBD） with three replications. Vegetable amaranth was rich in chlorophyll, β-cyanins, β-xanthins, betalains, carotene, ascorbic acid and total antioxidant. The genotypes VA14, VA16, VA18, VA15, and VA20 could be selected as amaranth vegtable varieties with high yields and abundance antioxidant leaf pigments and vitamins to produce juice. The genotypes VA13 and VA19 had above-average foliage yield and high antioxidant profiles while the genotypes VA2, VA3, VA9, VA11, VA12, and VA17 had a high antioxidant profiles and below-average foliage yield. These genotypes could be used as a donor parent for integration of potential high antioxidant profiles genes into other genotypes. The correlation study revealed a strong positive association among all the antioxidant leaf pigments, total antioxidant capacity and foliage yield. Selection based on total antioxidant capacity, antioxidant leaf pigments could economically viable to improve the yield potential of vegetable amaranth genotypes. Total carotene and ascorbic acid exhibited insignificant genotypic correlation with all the traits except total antioxidant capacity. This indicates that selection for antioxidant vitamins might be possible without compromising yield loss.

关键词： ascorbic acid betalain carotene chlorophyll β-cyanins β-xanthins total antioxidant capacity foliage yield correlation

Can Strategies to Cope with Hazard Shocks be Explained by At-Risk Households' Socioeconomic Asset Profile? Evidence from Tropical Cyclon-Prone Coastal Bangladesh

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International Journal of Disaster Risk Science 2017年第1期8卷 46-63页

作者： md.Nasif Ahsan Economics Discipline Khulna UniversityKhulna-9208Bangladesh

This article documents the results of an empirical investigation on the complex interplay between diverse coping mechanisms and the socioeconomic asset profiles of coastal households at risk. Focusing on household-level perceptions and responses to cyclone hazards, a case study was carried out in a poor area in Bangladesh that is prone to natural hazards. We developed and tested our own analytical models based on the asset approach. We conducted a face-to-face household survey in southwestern coastal Bangladesh, in the Koyra sub-district, in late *** asked 360 households affected by the May 2009 tropical Cyclone Aila about their hazard perceptions, preparedness, coping practices, and socioeconomic assets. The results suggest that the majority of households at risk perceive an increasing trend of different climate hazards,with a distinct dominance of tropical cyclones, storm surges, and flash floods in the study area, which resulted in a yearly average economic damage of USD 144 for each household in the first year after Aila. However, such damage is significantly and inversely correlated with the number of adopted coping practices. Significant and systematic differences exist between upstream and downstream households in the study area with respect to hazard perception, hazard induced damages, asset accessibility,and adopted diversified coping practices. The empirical findings suggest that the degree of adoption of coping practices depends primarily on elements of socioeconomic asset profile and the duration of the consequences of cyclone hazards. Disaster preparedness training seems to improve at-risk households' degree of information access and eventually leads them to adopt more coping practices to reduce adverse impacts of climate hazards. Area-specific practical modules on coping practices should be incorporated in curricula of disaster preparedness training to make people at risk more resilient to hazard shocks.

关键词： Climatic hazard risk Coastal Bangladesh Coping mechanism Cyclone Aila

Synergistic enhancement of photocatalytic and antimicrobial efficacy of nitrogen and erbium co-doped ZnO nanoparticles

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Journal of Rare Earths 2024年第5期42卷 859-868,I0002页

作者： Sudipta Mondal Moniruzzaman Jamal Sikder Ashikuzzaman Ayon md Jannatul Ferdous Anik md Muktadir Billah Department of Materials and Metallurgical Engineering Bangladesh University of Engineering and TechnologyDhaka1000Bangladesh School of Materials Engineering Purdue UniversityWest LafayetteIN47907USA Department of Materials Science and Engineering University of CaliforniaBerkeleyCA94720USA Department of Materials Science and Engineering Northwestern UniversityEvanstonI28USA

Using the chemical co-precipitation approach,a series of nitrogen(N) and erbium(Er) co-doped ZnO nanoparticles(NPs) was effectively synthesized to enhance the photocatalytic and antibacterial *** characterization techniques,including X-ray diffraction(XRD),X-ray photoelectron spectro scopy(XPS),scanning electron microscopy(SEM),UV-vis,and photoluminescence(PL) spectroscopy,were carried out to validate the evaluated photocatalytic and antibacterial *** analysis confirms the pure wurtzite ZnO phase without the presence of any secondary *** analysis confirms the succe ssful incorporation of nitrogen and erbium into the ZnO *** optical bandgap of ZnO calculated from UV-vis spectroscopy shows a redshift after Er-N co-doping,with the lowest bandgap of 3.215 eV calculated for Zn_(0.97)Er_(0.03)N_(0.01)O_(0.99) *** images demonstrate the formation of nanorods after N-Er co-doping,followed by gradually increase d rod diameter and length after N-Er ***,the photocatalytic activities of ZnO samples we re measured by their ability to facilitate the photodegradation of Rhodamine B under UV *** with 1 mol% N doping exhibits 88% photodegradation of RhB under UV light within 360 min,and the photodegradation and antibacterial activity are greatly improved with Er *** fact,3 mol% Er-1 mol% N doped ZnO NPs demonstrate the highest photocatalytic activity,with approximately 96% degradation after 360 min,as well as superior antibacterial activity against Staphylococcus aureus(Gram-positive bacteria) and Pseudomonas aeruginosa(Gram-negative bacteria) with the highest zone of inhibition(ZOI) of 16 nm,due to nanorod formation,increased reactive oxygen species(ROS),and decreased electron-hole recombination,as validated by SEM,XPS,and PL spectroscopy.

关键词： Chemical co-precipitation Co-doping Bandgap Photocatalysis Rare earths Antimicrobial

Bilateral Coupled Epsilon Negative Metamaterial for Dual Band Wireless Communications

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Computers, Materials & Continua 2022年第4期71卷 1263-1281页

作者： md Mhedi Hasan Mohammad Tariqul Islam md Moniruzzaman Mohd Hafiz Uddin Norsuzlin Binti Mohd Sahar md Samsuzzaman Department of Electrical Electronic and Systems Engineering Faculty of Engineering and Built EnvironmentUniversiti Kebangsaan MalaysiaSelangor43600Malaysia Space Science Centre Institute of Climate ChangeUniversiti Kebangsaan MalaysiaSelangor43600Malaysia Department of Computer and Communication Engineering Faculty of Computer Science and EngineeringPatuakhali Science and Technology UniversityPatuakhali8602Bangladesh

This work presents a dual band epsilon negative(ENG)metamaterial with a bilateral coupled split ring resonator(SRR)for use in C and X band wireless communication *** traditional split-ring resonator(SRR)has been amended with this engineered *** proposed metamaterial unit cell is realized on the 1.6 mm thick FR-4 printed media with a dimension of 10×10 *** resonating patch built with a square split outer *** interlinked inner rings are coupled vertically to the outer ring to extend its electrical length as well as to tune the resonance *** simulation is performed using CST studio suite 2019 to design and performance *** transmission coefficient(S21)of the proposed unit cell and array configuration exhibits two resonances at 6.7 and 10.5 GHz with wide bandwidth extended from 4.86 to 8.06 GHz and 10.1 to 11.2 GHz,*** permittivity is noted at frequencies between 6.76–9.5 GHz and 10.5–12 GHz,consecutively,with near-zero refractive index and *** optimal EMR value depicts the compactness of the proposed *** 1×2,2×2 and 4×4 arrays are analyzed that shows similar response compared to the unit *** results of the 2×2 array shows the close similarity of S21 response as compared to *** observed properties of the proposed unit cell ascertain its suitability for wireless communications by enhancing the gain and directivity of the antenna system.

关键词： Metamaterial epsilon negative near-zero index split ring resonator wireless communications

Influence of dielectric barrier discharge treatment on mechanical and dyeing properties of wool

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Plasma Science and Technology 2018年第6期20卷 89-98页

作者： Rahul NAVIK Sameera SHAFI md Miskatul ALAM md Amjad FAROOQ Lina LIN Yingjie CAI Hubei Provincial Engineering Laboratory for Clean Production and High Value Utilization of Bio-Based Textile Materials Wuhan Textile UniversityWuhan 430073People＇s Republic of China School of Chemistry and Chemical Engineering Shanghai Jiao Tong UniversityShanghai 200240People＇s Republic of China

Physical and chemical properties of wool surface significantly affect the absorbency,rate of dye bath exhaustion and fixation of the industrial ***,surface modification is a necessary operation prior to coloration process in wool wet processing *** treatment is an effective alternative for physiochemical modification of wool ***,optimum processing parameters to get the expected modification are still under investigation,hence this technology is still under development in the wool wet processing ***,in this paper,treatment parameters with the help of simple dielectric barrier discharge plasma reactor and air as a plasma gas,which could be a promising combination for treatment of wool substrate at industrial scale were schematically studied,and their influence on the water absorbency,mechanical,and dyeing properties of twill woven wool fabric samples are *** is expected that the results will assist to the wool coloration industries to improve the dyeing processes.

关键词： air plasma reactive dye surface energy wool

Measurement and correlation of solubility of diosmin in four pure solvents and β-cyclodextrin solution at 298.15K to 333.15K

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Chinese Journal of Chemical Engineering 2015年第5期23卷 812-815页

作者： md Khalid Anwer Faiyaz Shakeel Department of Pharmaceutics College of Pharmacy Salman Bin Abdulaziz University Center of Excellence in Biotechnology Research King Saud University Department of Pharmaceutics College of Pharmacy King Saud University

The aim of present study was to measure and correlate the solubility of poorly water-soluble flavonoid diosmin in water, ethanol, isopropyl alcohol （IPA）, polyethylene glycol-400 （PEG-400） and β-cyclodextrin （β-CD） aqueous solution （0.02 mol·L^-1 ）. The solubility of diosmio was measured using the shake flask method from （298.15 to 333.15） K at atmospheric pressure. The experimental solubilities of diosmin were regressed by the modified Apelblat model with a relative deviation in the range of 0.048% to 5.940%. The correlation coefficients were observed in the range of 0.9957 to 0.9995. The solubility of diosmin was found to be increased with temperature in all sample matrices investigated. The mole fraction solubility of diosmin was found to be higher in 5-CD aqueous solution and PEG-400 as compared to water, ethanol and IPA. Based on solubility data of present study, diosmin was considered as practically insoluble in water, insoluble in ethanol ＆ IPA and soluble in PEG- 400 and β-CD aqueous solution.

关键词： Apelblat model Cyclodextrin Diosmin Solubility Thermodynamics