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LaF3-passivation of Porous Silicon for the Enhancement and Stabilization of Photoluminescence

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材料科学与工程（中英文版） 2010年第4期4卷 60-65页

作者： Sinthia Shabnam Mou md. Atowar Rahman Mushtaq ahmed Sobhan md. Abdur Rahman Abu Bakar md.Ismail Department of Applied Physics and Electronic Engineering Rajshahi University Rajshahi 6205 Bangladesh

Amelioration of Salinity Stress in Maize Seed Germination and Seedling Growth Attributes through Seed Priming

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Open Journal of Soil Science 2018年第5期8卷 137-146页

作者： Lucky Akter Oli ahmed Fakir md. Khairul Alam Mahbub Ul Islam Priyanka Chakraborti md. Jahangir Alam md. Harunur Rashid Mahfuza Begum md. Abdul Kader Department of Agronomy Bangladesh Agricultural University Mymensingh Bangladesh Bangladesh Agricultural Research Institute ARS Satkhira Bangladesh Bangladesh Agricultural Research Institute Gazipur Bangladesh Bangladesh Agricultural Research Institute On-Farm Research Division Patuakhali Bangladesh Global Centre for Environmental Remediation (GCER) University of Newcastle Callaghan Australia

Germination of seeds and growth of seedling respond to seed priming as priming can guard the damage of salinity stress. A study conducted in the net house of the Department of Agronomy, BAU, Mymensingh during the period from November 2012 to April 2013 investigated the ameliorative effect of seed priming on seed germination and seedling attributes of maize under various salinity stress conditions. The experiment consisted of five seed priming and four salinity levels (NaCl) and laid out in a Completely Randomized Design (CRD) with three replications. Seed germination and seedling attributes of maize varied due to salinity stress and priming. The highest seed germination (95.7%) was recorded when no stress was imposed under hydropriming (48 hours). The germination of seeds performed even well (92.3%) when treated with hydropriming (48 hours) and NaCl@0.25 dS·m-1 which was followed by hydropriming (24 hours) under no salinity imposed and NaCl@0.25 dS·m-1 salinity. Hydropriming for 48 hours without salt stress performed the best on number of leaves seedling-1 (8), shoot length (28.2 cm), root length (14.5 cm), fresh weight (100.8 g) and dry weight of seedling (50.3 g). The germination and seedling growth parameters were reduced with the increase in salinity levels irrespective of priming while all seed priming treatments showed ameliorative effects. However, reduction in seed germination and seedling attributes were minimal with hydropriming for 48 hours. The results revealed that priming of maize seeds could be used for amelioration of salinity stress and hydropriming for 48 hours appeared as the best seed priming treatment.

关键词： Germination Halopriming Hydropriming Osmopriming Seedling Attributes

A Review on D 614G Mutation with Bangladesh Scenario

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Advances in Infectious Diseases 2020年第3期10卷 249-255页

作者： Arifa Akram Mohammad Jahidur Rahman Khan md. Bayzid Bin Monir md. Reaz Uddin Chowdhury Mahmuda Yeasmin md. Maruf ahmed Molla Tasnim Nafisa Department of Virology National Institute of Laboratory Medicine and Referral Center Dhaka Bangladesh Department of Microbiology Shaheed Suhrawardy Medical College Dhaka Bangladesh Department of Microbiology National Institute of Laboratory Medicine and Referral Center Dhaka Bangladesh Abdul Malek Ukil Medical College Noakhali Bangladesh

With the COVID-19 pandemic, disparities between the infection rate and death rate in different countries become a major concern. In some countries, lower mortality rate compared to others can be explained by better testing capacity and intensive care facilities. Complete SARS-CoV-2 genome sequences from different countries of the world are continually submitted to Global Initiative for Sharing All Influenza Data using Next Generation Sequencing method. A SARS-CoV-2 variant with a D 614G Mutation in the spike (S) protein has become the most dominant form in the global pandemic. There are a number of ongoing studies trying to relate this mutation with the infectivity, mortality, transmissibility of the virus and its impact on vaccine development. This review aims to accumulate the major findings from some of these studies and focus its future implication. Some studies suggested D 614G strain has increased binding capacity, it affects more cells at a faster rate, so has a high transmissibility. Patients infected with this strain were found with high viral load. But still now there is no such evidence that this strain produces more severe disease as well as increased mortality. The structural change of spike protein produced by D 614G mutation was minor and did not hamper the vaccine efficacy. Some studies showed antibodies produced against D614 strain can neutralize G614 strain and vice versa. Whenever a mutation occurs in spike protein there are always chances of affecting the infectivity, transmissibility, vaccine efficacy. Therefore, more studies are required to find out the overall effect of D 614G mutation.

关键词： Coronavirus D 614G Mutation SARS-CoV-2 Spike Protein Global Initiative for Sharing All Influenza Data (GISAID)

Synthesis and Characterization of Copper Doped Zinc Oxide Thin Films Deposited by RF/DC Sputtering Technique

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Journal of Shanghai Jiaotong university(Science) 2023年第2期28卷 172-179页

作者： KHAN Mohibul ALAM md.Shabaz ahmed Sk.Faruque Nanoscience Laboratory Department of PhysicsAliah UniversityKolkata 700160India

Undoped and copper(Cu)doped zinc oxide(Zn_(1-x)Cu_(x)O,where x=0-0.065)nano crystal thin films have been deposited on glass substrate via RF/DC reactive co-sputtering *** aim of this work is to investigate the crystal structure of ZnO and Cu doped ZnO thin films and also study the effect of Cu doping on optical band gap of ZnO thin *** identification and confirmation of the crystallinity,film thickness and surface morphology of the nano range thin films are confirmed by using X-ray diffractometer(XRD),scanning electron microscope and atomic force *** XRD peak at a diffractive angle of 34.44°and Miller indices at(002)confirms the ZnO thin *** size of undoped ZnO thin films is 27 nm and decreases from 27 nm to 22 nm with increasing the atomic fraction of Cu(x_(Cu))in the ZnO thin films from 0 to 6.5%respectively,which is calculated from XRD(002)*** different bonding information of all deposited films was investigated by Fourier transform infrared spectrometer in the range of wave number between 400 cm^(-1) to 4000 cm^(-1).Optical band gap energy of all deposited thin films was analyzed by ultraviolet visible spectrophotometer,which varies from 3.35 eV to 3.19 eV with the increase of x_(Cu) from 0 to 6.5%*** energy of the deposited thin films increases from 115 meV to 228 meV with the increase of x_(Cu) from 0 to 6.5% respectively.

关键词： Cu-ZnO thin films RF/DC sputtering technique X-ray diffraction atomic force microscope optical property Urbach energy

Wireless Head Gesture Controlled Robotic Wheel Chair for Physically Disable Persons

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Journal of Sensor Technology 2020年第4期10卷 47-59页

作者： Shadman Mahmood Khan Pathan Wasif ahmed md. Masud Rana md. Shahjalal Tasin Faisul Islam Anika Sultana Department of Mechatronics Rajshahi University of Engineering & Technology Rajshahi Bangladesh Department of Electrical & Electronic Engineering Rajshahi University of Engineering & Technology Rajshahi Bangladesh Department of EEE Rajshahi University of Engineering & Technology Rajshahi Bangladesh

A robotic wheelchair is assumed to be capable of doing tasks like navigation, obstacle detection, etc. using sensors and intelligence. The initial part of the work was development of a cap controlled wheelchair to test and verify the gesture operation. Following that, a real time operating wheelchair was developed consisting of mode changing option between joystick control mode and head gesture control mode as per as the user’s requirement. The wheelchair consists of MPU6050 sensor, joystick module, RF module, battery, dc motor, toggle switch and Arduino. The movement of the head is detected by MPU6050 and the signal is transmitted to the microcontroller. Then the signal is processed by controller and motion of wheelchair is enabled for navigation. The wheelchair was capable of moving left, right, forward and backward direction. The speed of the wheelchair was 4.8 km/h when tested. Design objective of the wheelchair included cost effectiveness without compromising safety, flexibility and mobility for the users.

关键词： Head Gesture Wheel Chair Arduino Motor Driver Joystick Module

Effect of Exchange-Correlation Functional on the Structural, Mechanical, and Optoelectronic Properties of Orthorhombic RbSrBr3 Perovskite

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Materials Sciences and Applications 2024年第6期15卷 137-154页

作者： Fatema Najrin Rabeya Bakar Sarna md. Alamin Sarker Budrun Neher md. Mahbubur Rahman Bhuiyan Farid ahmed Department of Physics Jahangirnagar University Dhaka Bangladesh Department of Electrical and Electronics Engineering Green University of Bangladesh Purbachal American City Kanchan Rupganj Narayanganj-1461 Dhaka Bangladesh

In the present study, the effect of the exchange-correlation functional on the structural, mechanical, and optoelectronic properties of orthorhombic RbSrBr3 perovskite has been investigated using various functionals in Density Functional Theory (DFT) with the CASTEP code. The optimized lattice parameters are quite similar for all the functionals. The electronic properties have shown that RbSrBr3 perovskite is a wide direct band gap compound with a band gap energy ranging from 4.296 eV to 4.494 eV for all the functionals. The mechanical parameters like elastic constants, Young’s modulus, Shear modulus, Poisson’s ratio, Pugh’s ratio, and an anisotropic factor reveal that the RbSrBr3 perovskite has ductile behavior and an anisotropic nature which signifies the mechanical stability of the compound. The Debye temperature might withstand lattice vibration heat. High absorption coefficient (>104 cm−1), high optical conductivity, and very low reflectivity have been found in the RbSrBr3 perovskite for all functions. The computed findings on the RbSrBr3 perovskite suggested that the presented studied material is potentially applicable for photodetector and optoelectronic devices.

关键词： Density Functional Theory Mechanical Properties Photodetector Ductility Anisotropic Factor

Scalable Process to Develop Durable Conductive Cotton Fabric

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Advanced Fiber Materials 2020年第6期2卷 291-301页

作者： md.Abdullah Al.Mamun md.Touhidul Islam md.Momtaz Islam Kazi Sowrov md.Afzal Hossain Dewan Murshed ahmed Hasan Shahariar Bangladesh University of Textiles Dhaka 1208Bangladesh University of Manchester ManchesterUK Funxion Wear IncRaleighNC 27606USA

Developing a scalable process is critical to manufacture conductive fabric for commercial *** paper describes a scalable coating process that is compatible with existing industrial finishing processes of *** this process,the fabric is continuously dipped in water-based metal salt and the reducing agent solution to impart conductive particles on the fiber *** 10 consecutive cycles of dip coating,the fabric shows 6Ω/*** *** process is tuned to minimize process cost and material cost,and maximize the durability of the *** paper also introduces an easy protective coating technique of the conductive fabric that improves the durability of the conductive fabric without sacrificing the comfort properties of textile fabrics such as breathability and *** encapsulated conductive fabric shows good air-permeability and it is 6.96 cm^(3)/cm^(2)/***,the conductivity of the encapsulated fabric is quite stable after four accelerated washing ***,the fabric remains conductive on the surfaces and is suitable for using as a conductive track and connectors.

关键词： Conductive fabric Scalable process Layer by layer deposition Durability

Design, Simulation &Optimization of 2D Photonic Crystal Power Splitter

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Optics and Photonics Journal 2013年第2期3卷 13-19页

作者： Rajib ahmed md. Masruf Khan Rifat Ahmmed Abdul Ahad Department of Electrical & Electronic Engineering University of Information Technology & Science Dhaka Bangladesh Department of Electronics & Telecommunication Engineering Rajshahi University of Engineering & Technology Rajshahi Bangladesh Department of Physics Bangladesh University of Engineering and Technology Dhaka Bangladesh Photonic Networks Engineering (MAPNET) Scuola Superiore Sant’Anna Pisa Italy

A very compact (80 - 100 μm2) integrated power splitting devices with two outputs (1 × 2), four outputs (1 × 4) and six outputs (1 × 6) channel has been designed, simulated and optimized for Telecommunication purpose with T-Junction, Y-Junction, PC line defect waveguides integrated with multimode interference block (PCLD-MMI) and multiple line defect PC waveguides (MLDPCW) configurations. The optical modeling of these proposed structures was investigated by finite difference time domain (FDTD) simulation. With the optimization of the parameters (Hole Radius, R = 0.128 μm, Input Diameter, D = 1.02 μm, Input wavelength, λ = 1.55 μm, Substrate Reflective Index, nsub = Si(1.52), Photonic Crystal Material, npcs = InAs(3.45), and Rectangular crystal structure), 1 × 2 for Y-Junction (100%), 1 × 4 for T-Junction (92.8%) and 1 × 6 configuration for MLDPCW (81%) show maximum power transmission.

关键词： Power Splitter Photonic Crystals Finite Difference Time Domain PCLDMMI MLDPCW

Regional Variation of Temperature and Rainfall in Bangladesh: Estimation of Trend

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Open Journal of Statistics 2015年第7期5卷 652-657页

作者： Abdur Rahman md. Jibanul Haque Jiban Sohul ahmed Munna Department of Statistics Shahjalal University of Science and Technology Kumargaon Bangladesh

This study mainly focuses on exploring the regional variation of the changing patterns of temperature and rainfall in Bangladesh. The analysis is based on the temperature and rainfall variation in Bangladesh over five regions as Dhaka, Cox’s Bazar, Rajshahi, Bogra and Sylhet. The duration of the study period was chosen as 1953-2012 for Dhaka, 1948-2012 for Cox’s Bazar, 1972-2012 for Rajshahi, 1958-2012 for Bogra and 1957-2012 for Sylhet. The findings of the non-parametric Mann-Kendal test reveals that significant increase of maximum temperature has been found in Cox’s Bazar and Sylhet. Significant decrease of maximum temperature has been found in Dhaka and Bogra. Significant increase of minimum temperature has been found in Dhaka and Cox’s Bazar whereas significant decrease has been found in Rajshahi. Significant decrease of rainfall has been found in Rajshahi among the study region. The maximum temperature increases significantly by 0.021 degree Celsius per year in Cox’s Bazar and Sylhet. In case of minimum temperature highest increase is found in Dhaka by 0.049 degree Celsius followed by Cox’s Bazar (0.038 degree Celsius per year) whereas significant decrease has been found in Rajshahi by 0.047 degree Celsius per year.

关键词： Trend Temperature Rainfall Regional Variation Bangladesh