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Materials Sciences and Applications 2023年第9期14卷 458-472页

作者： md. Ferdous Wahid Ushna Das Bidesh Kumer Paul Shuvo Paul md. Nuralam Howlader md. Sazedur rahman Department of Electrical and Electronic Engineering Hajee Mohammad Danesh Science and Technology University Dinajpur Bangladesh

The paper reported the design and thorough analysis of a thin-film solar cell (TFSC) based on molybdenum disulfide (MoS2) with an integrated Copper(I) Oxide (Cu2O) hole transport layer (HTL), employing the one-dimensional Solar Cell Capacitance Simulator (SCAPS-1D) software. By varying crucial parameters such as absorber layer thickness, doping density, and bulk defect density, as well as HTL thickness, doping concentration, and electron affinity, defect density at ZnO/absorber and absorber/Cu2O interfaces, and operating temperature, we explored key photovoltaic measures including open circuit voltage (Voc), short-circuit current density (Jsc), fill-factor (FF), and power conversion efficiency (PCE) of the hetero-junction solar cell. The study demonstrated an efficiency of 18.87% for the MoS2 solar cell without HTL, while the proposed solar cell (SC) utilizing Cu2O HTL and optimized device structure exhibited a remarkable PCE of 26.70%. The outcomes derived from the present study offer valuable insights for the progress of a highly efficient and economically viable MoS2 hetero-junction TFSC.

关键词： Solar Cell Thin Film SCAPS-1D Hetero-Junction HTL Defect Density

Improvement on electrochemical performances of nanoporous titania as anode of lithium-ion batteries through annealing of pure titanium foils

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Journal of Energy Chemistry 2018年第1期27卷 250-263页

作者： md.arafat rahman Yat Choy Wong Guangsheng Song De Ming Zhu Cuie Wen Faculty of Science Engineering and TechnologySwinburne University of Technology Department of Mechanical Engineering Chittagong University of Engineering and Technology School of Material Science&Engineering Anhui University of Technology School of Engineering RMIT University

The effect of annealing of Ti foils before anodization on the morphology and electrochemical performance of resultant nanoporous anatase TiO2 （np-TiO2） as anode in rechargeable lithium-ion batteries （LIBs） was investigated. The np-TiO2 anode fabricated from annealed Ti foils exhibited higher specific surface area and reduced pore diameter compared to np-TiO2 electrode fabricated from as-received Ti foils. The highly porous np-TiO2 anode fabricated from annealed Ti foils exhibited 1st discharge capacity of 453.25 mAh/g and reduced to 172.70 mAh/g at 1 C current rate after 300 cycles; whilst the np-TiO2 electrode fabricated from the as-received Ti foils exhibited 1st discharge capacity of 213.30 mAh/g and reduced to 160.0 mAh/g at 1 C current rate after 300cycles. Even after 400cycles, such np-TiO2 electrode exhibited a reversible capacity of 125.0 mAh/g at 2.5 C current rate. Compared to the untreated Ti foils, the enhanced electro- chemical performance of np-TiO2 anode fabricated from annealed Ti foils was ascribed to the annealing- induced removal of residual stress among the Ti atoms. The benefit of annealing process can reduce pore size of as-fabricated np-TiO2.

关键词： Annealing Nanoporous Anatase Titanium oxide Anode Lithium-ion battery

An Efficient Reference Free Adaptive Learning Process for Speech Enhancement Applications

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Computers, Materials & Continua 2022年第2期70卷 3067-3080页

作者： Girika Jyoshna md.Zia Ur rahman L.Koteswararao Deptartment of Electronics and Communication Engineering Koneru Lakshmaiah Education FoundationKL UniversityVaddeswaramGunturAndhra PradeshIndia Department of Electronics and Communication Engineering Koneru Lakshmaiah Education FoundationKL UniversityHyderabadTelanganaIndia

In issues like hearing impairment,speech therapy and hearing aids play a major role in reducing the *** of noise signals from speech signals is a key task in hearing aids as well as in speech *** the transmission of speech signals,several noise components contaminate the actual speech *** paper addresses a new adaptive speech enhancement(ASE)method based on a modified version of singular spectrum analysis(MSSA).The MSSA generates a reference signal for ASE and makes the ASE is free from feeding reference *** MSSA adopts three key steps for generating the reference from the contaminated speech *** are decomposition,grouping and *** generated reference is taken as a reference for variable size adaptive learning *** this work two categories of adaptive learning algorithms are *** are step variable adaptive learning(SVAL)algorithm and time variable step size adaptive learning(TVAL).Further,sign regressor function is applied to adaptive learning algorithms to reduce the computational complexity of the proposed adaptive learning *** performance measures of the proposed schemes are calculated in terms of signal to noise ratio improvement(SNRI),excess mean square error(EMSE)and misadjustment(MSD).For cockpit noise these measures are found to be 29.2850,-27.6060 and 0.0758 dB respectively during the experiments using SVAL *** considering the reduced number of multiplications the sign regressor version of SVAL based ASE method is found to better then the counter parts.

关键词： Adaptive algorithm speech enhancement singular spectrum analysis reference free noise canceller variable step size

Efficient removal of heavy metals from electroplating wastewater using polymer ligands

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Frontiers of Environmental Science & Engineering 2016年第2期10卷 352-361页

作者： md. Lutfor rahman Shaheen M. SARKAR Mashitah Mohd YUSOFF Faculty of Industrial Sciences & Technology Universiti Malaysia Pahang 26300 Gambang Kuantan Malaysia

Poly（hydroxamic acid）-poly（amidoxime） che- lating ligands were synthesized from poly（methyl acrylate-co-acrylonitrile） grafted acacia cellulose for removing toxic metal ions from industrial wastewaters. These ligands showed higher adsorption capacity to copper （2.80 mmol. g-l） at pH 6. In addition, sorption capacities to other metal ions such as iron, zinc, chromium, and nickel were also found high at pH 6. The metal ions sorption rate （tl/2） was very fast. The rate of adsorption of copper, iron, zinc, chromium, nickel, cobalt, cadmium and lead were 4, 5, 7, 5, 5, 8, 9 and 11 min, respectively. Therefore, these ligands have an advantage to the metal ions removal using the column technique. We have successfully investigated the known concentration of metal ions using various parameters, which is essential for designing a fixed bed column with ligands. The wastewater from electroplating plants used in this study, having chromium, zinc, nickel, copper and iron, etc. For chromium wastewater, ICP analysis showed that the Cr removal was 99.8% and other metal ions such as Cu, Ni, Fe, Zn, Cd, Pb, Co and Mn removal were 94.7%, 99.2%, 99.9%, 99.9%, 99.5%, 99.9%, 95.6% and 97.6%, respectively. In case of cyanide wastewater, the metal removal, especially Ni and Zn removal were 96.5 and 95.2% at higher initial concentra- tion. For acid/alkali wastewater, metal ions removing for Cd, Cr and Fe were 99.2%, 99.5% and 99.9%, respectively. Overall, these ligands are useful for metal removal by column method from industrial wastewater especially plating wastewater.

关键词： heavy metals adsorption wastewater chelat-ing ligands plating industry

Effect of Strain Rate on Tensile Behavior of Sn-9Zn-xAg-ySb;{(x, y) = (0.2, 0.6), (0.2, 0.8), (0.6, 0.2), (0.8, 0.2)} Lead-Free Solder Alloys

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Materials Sciences and Applications 2023年第4期14卷 273-283页

作者： Shihab Uddin md. Abdul Gafur Mohammad Obaidur rahman Department of Physics Jahangirnagar University Savar Dhaka Bangladesh Pilot Plant and Process Development Centre Dhaka Bangladesh

The tensile properties of Sn-9Zn-xAg-ySb;{(x, y) = (0.2, 0.6), (0.2, 0.8), (0.6, 0.2), (0.8, 0.2)} lead-free solders were investigated. All the test samples were annealed at 150°C for 1 hour. The tests are carried out at room temperature at the strain rate of 4.17 × 10-3 s-1, 20.85 × 10-3 s-1, and 208.5 × 10-3 s-1. It is seen that the tensile strength increases and the ductility decrease with increasing the strain rate over the investigated range. From the strain rate change test results, the strain sensitivity values are found in the range of 0.0831 to 0.1455 due to the addition of different alloying elements.

关键词： Lead-Free Solder Strain Rate Strain Sensitivity Ductility Tensile Properties

Cyclic liquefaction screening of sand with non-plastic fines:Critical state approach

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Geoscience Frontiers 2020年第2期11卷 429-438页

作者： md.Mizanur rahman TGSitharam Natural and Built Environments Research Centre(NBERC) School of Natural and Built EnvironmentsUniversity of South AustraliaMawson LakesSA 5095Australia Department of Civil Engineering Indian Institute of Science(IISc)BangaloreIndia

There have been significant advances in the application of critical state,CS,in liquefaction potential *** was done by comparing state parameter,j with estimated characteristic cyclic stress ratio,CSR due to an earthquake.A cyclic resistance ratio,CRR curve,which can be determined from cyclic liquefaction tests,separates historical liquefied and non-liquefied data points(j,CSR).On the other hand,the concepts of equivalent granular state parameter,j*,which was developed for sands with fines,can be used in lieu j to provide a unifying framework for characterizing the undrained response of sands with non/low plasticity fines,irrespective of fines content(fc).The present work combines these two propositions,and by merely substituting j*for j into the aforementioned CS approach to capture the influence of fc.A series of static and cyclic triaxial tests were conducted,separately and independently of the concept of j*,for sand with up to fc of 30%.The clean sand was collected from Sabarmati river belt at Ahmedabad city in India which was severely affected during the Bhuj earthquake,*** experimental data gave a single relation for CRR and j*which was then used to assess liquefaction potential for a SPT based case study,where fc varies along the *** prediction matched with the field observation.

关键词： Critical state State parameter Liquefaction Sands Fines Constitutive model

Molecular Identification of Alternaria alternate (Fr.) Keissl. from the Leaf Blight Disease of Centella asiatica L.

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Natural Science 2023年第8期15卷 223-232页

作者： Nusrat Binte Alam Farhana rahman md. Nuhu Alam Department of Botany Jahangirnagar University Dhaka Bangladesh

Centella asiatica (L.), frequently known as Thankuni, is an important ethnobotanical plant in Bangladesh. This study was conducted to evaluate the morphological characteristics, cultural factors and molecular identification of the causal agent of Alternaria leaf blight disease of C. asiatica. The potato dextrose agar (PDA) medium recorded the maximum mycelial growth (69 mm), followed by the yeast extract agar (YEA) medium, while the honey peptone agar (HPA) medium recorded the lowest growth (27 mm). The optimal pH and temperature for mycelial growth of Alternaria alternata were 6 and 30°C, respectively. Internal transcribed spacer (ITS) region of Alternaria alternata PCR products measured 558 bp and blast search showed 99% sequence similarity with Alternaria alternata species complex. To the best of our knowledge, Alternaria leaf blight disease caused by Alternaria alternata is the first record in Bangladesh.

关键词： Alternaria alternata Centella asiatica Molecular Identification Mycelial Growth

Compliance of Physicians with Standard Precautions of Handling Patients with Infectious Respiratory Disease

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Open Journal of Preventive Medicine 2023年第5期13卷 139-168页

作者： Tohura Sharmin md. Shafiur rahman Abir Bin Sajj Department of Community Medicine Ad-Din Women’s Medical College Dhaka Bangladesh Department of Occupational and Environmental Health National Institute of Preventive and Social Medicine (NIPSOM) Dhaka Bangladesh Department of Cornea and Refractive Surgery Vision Eye Hospital Dhaka Bangladesh

Background: Standard precautions (SPs) are the minimum infection prevention practices that aim to protect Health care workers (HCWs) including physicians and prevent them from transmitting the infections to their patients. Purpose: To assess the level of compliance of physicians with standard precautions of handling patients with infectious respiratory disease. Method: A cross sectional questionnaire-based study was conducted in two tertiary level hospitals named M Abdur Rahim Medical College and Hospital, Dinajpur, Bangladesh and Rajshahi Medical College and Hospital, Rajshahi, Bangladesh to assess the level of compliance of physicians with standard precautions. Purposive sampling technique was applied as per inclusion criteria and data was collected by face to face interview from 285 physicians. Statistical analysis of the results was done by SPSS and a p value less than 0.05 was considered as significant. Result: The study revealed that maximum physicians (76.5%) handling patients with infectious respiratory disease had a moderate level of compliance with standard precautions. 78.6% of the physicians had moderate level of awareness about standard precautions. Only 20.35% of the physicians had training on infection control. 94.4% of the respondents didn’t know the component of standard precaution and most of the physicians were not aware of the sequence of wearing and removing the different components of PPEs. Conclusion: The study result implies that with increased awareness, the compliance of the physicians with standard precautions increased. The main reasons of non-compliance with standard precautions were found to be lack of resources, lack of regular training and excess workload.

关键词： Compliance of Physicians Awareness of Physicians Standard Precautions Infectious Disease Respiratory Disease Infectious Respiratory Disease

Using Magnesium Sulfate to Prevent Atrial Fibrillation after Coronary Artery Bypass Grafting Surgery: A Single Centre Experience in Bangladesh

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World Journal of Cardiovascular Diseases 2023年第9期13卷 565-577页

作者： Manoj Tiwari md. Abir Tazim Chowdhury Hema Poudel Munama Magdum md. Mostafizur rahman Vivek Kumar Jha md. Ahaduzzaman md. Abul Bashar Maruf Department of Cardiovascular and Thoracic Surgery B.P. Koirala Memorial Cancer Hospital Bharatpur Chitwan Nepal Department of Cardiothoracic and Vascular Surgery Evercare Hospital Dhaka Dhaka Bangladesh Department of Dermatology and Venerology Bangabandhu Sheikh Mujib Medical University Dhaka Bangladesh Department of Community Medicine Shaheed Monsur Ali Medical College Dhaka Bangladesh Department of Cardiac Surgery Bangabandhu Sheikh Mujib Medical University Dhaka Bangladesh Department of Cardiac Surgery Ibn Sina Specialized Hospital Dhaka Bangladesh

Background: Atrial fibrillation commonly occurs following cardiac surgery, particularly after coronary artery bypass grafting. Magnesium, known for its stabilizing effect on cell membranes, has shown promise in preventing postoperative atrial fibrillation. This study aimed to assess the impact of intravenous magnesium infusion in preventing atrial fibrillation after off-pump coronary artery bypass grafting, where maintaining stable cell membranes is crucial in averting this complication. Methods: A cross-sectional study was conducted at the Department of Cardiac Surgery, Bangabandhu Sheikh Mujib Medical University, from March 2020 to February 2022. Sixty-six patients who underwent off-pump coronary artery bypass grafting were enrolled and divided into two groups. Group A (n = 33) received intravenous magnesium sulfate (10 mmol/2.47gm) for three days after surgery, while Group B (n = 33) did not receive magnesium sulfate. Postoperative atrial fibrillation occurrence in the Intensive Care Unit (ICU) within three days after surgery was evaluated using convenient sampling. Statistical analysis was performed with SPSS version 26.0, utilizing independent Student’s t-test for continuous data and Chi-square and Fisher’s exact test for categorical data. A p-value of ≤0.05 was considered statistically significant. Results: No significant differences in age or gender were observed between the two groups. Group B exhibited significantly lower magnesium levels than Group A on the 0th, 1st, 2nd, and 3rd days post-surgery. Additionally, Group B experienced a higher incidence of postoperative atrial fibrillation, longer ICU stays, and two mortalities. The study did not detect any adverse effects associated with magnesium infusion. Conclusion: It has been demonstrated that administering magnesium intravenously after off-pump coronary artery bypass grafting can lower the chances of developing atrial fibrillation. This demonstrates the poten

关键词： Atrial Fibrillation (AF) Coronary Artery Bypass Grafting (CABG) Postopera-tive Atrial Fibrillation (POAF) Magnesium Sulfate Bangladesh.

Infant and Under-five Mortality in Bangladesh: Discriminant Analysis

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Chinese Journal of Population,Resources and Environment 2010年第4期8卷 79-84页

作者： rahman md. Mahfuzar IsIam md. Rafiqul Population Science and Human Resource Development University of Rajshahi

Bangladesh is on target for achieving the Millennium Development Goal 4 relating to infant and under-five mortality because of very rapid reduction in mortality in recent years. But this rate of reduction may be difficult to sustain and may hamper the achievement of Millennium Development Goal 4. Therefore, the main objective of this paper is to discuss and compare the dif- ferent covariates of infant and under-five mortality in the context of overall country, urban and rural levels of Bangladesh using discriminant analysis. For this, the data are taken from Bangladesh Demographic and Health Survey, 2004. In discriminant analysis, the stepwise procedure has been picked up and only the significant variables are ranked according to the rank of Wilk's Lambda val- ues. The canonical discriminant function coefficients (unstandard- ized and standardized) for the predictor variables have also been calculated. Both the results show that breastfeeding is the most important variable in discriminating the two groups of mothers, i.e., mothers experiencing to infant mortality or not and mothers experiencing to under-five mortality or not. The related results of discriminant function also indicate that the discriminant func- tion is statistically significant and discriminates well. Therefore, improvements in the health system are essential for promoting the breastfeeding practices (both inclusive and exclusive), which may be the effective strategies to reach families and communities with targeted messages and information.

关键词： infant and under-five mortality breastfeeding prac- tices discriminant analysis