检索结果-南通市图书馆

A Review on Zinc Sulphide Thin Film Fabrication for Various Applications Based on Doping Elements

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Materials Sciences and Applications 2018年第9期9卷 751-778页

作者： md. Anisuzzaman Shakil Sangita Das md. Ashiqur rahman Umma Salma Akther md. Kamrul Hassan Majumd.r md. khalilur rahman Department of Physics Comilla University Comilla Bangladesh Department of Computer Science and Engineering Comilla University Comilla Bangladesh Department of Electrical and Computer Engineering Boise State University Boise ID USA Department of Electronic Materials and Devices Engineering Soonchunhyang University Asan Chungnam South Korea

Zinc Sulfide (ZnS) thin film has attracted increasing attention due to their potential applications in the new generation of nano-electronics and opto-electronics devices. The physical and chemical properties of ZnS have outstanding quality for different applications. Moreover, ZnS doped with various elements are creating a new era for both academic research and industrial applications. So, the optical properties of modified ZnS thin film will help us to find a suitable doping element for convenient deposition which may enhance the conductance and transmitting properties of the film. This review work has been carried out to explore the four-modification elements that constitute Cu, Ni, Co & Fe as descending order of atomic number corresponding to Zn, along with some potential applications considering the recent research work with other doping elements too such as Al, C, Pt etc. For example, FE, FET, Catalytic, Solar cell, Electroluminescence, Fuel cell, different sensors (Chemical sensors, Bio-sensors, Humidity sensors, light sensors, UV light sensors) and nanogenerators use ZnS thin film.

关键词： ZnS ZnS Properties Doping Elements (Cu Ni Co Fe) Sensors Generators

A Review of the Study on the Electromigration and Power Electronics

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Electronics Cooling and Thermal Control 2016年第1期6卷 19-31页

作者： md. khalilur rahman Abul Monsur Mohammed Musa Budrun Neher Kawchar Ahmed Patwary Mohammad Atiqur rahman md. Shariful Islam Department of Physics Comilla University Comilla Bangladesh Department of Physics University of Chittagong Chittagong Bangladesh Department of Chemistry Comilla University Comilla Bangladesh Department of ICT Comilla University Comilla Bangladesh

Electromigration is a main challenge in the pursuit of power electronics, because physical limit to increase current density in power electronics is electromigration (EM), whereas much higher electrical current and voltage are required for power electronics packaging. So the effect of EM is an important issue in applications where high current densities are used, such as in microelectronics and related structures (e.g., Power ICs). Since the structure size of integrated circuits (ICs) decreases and the practical significance of this effect increases, the result is EM failure. On the other hand, in the next generation power electronics technology electrical current density is expected to exceed 107 A/cm2 which is another challenge. This review work has been carried out to identify the mechanism of EM damage in power electronics (e.g., pure metallization and solder joints) and also how to control this kind of damage.

关键词： Voids and Hillocks Interconnect Solder Joint Thermomigration MTF Reliability of IC

A Physician Suffering from COVID-19 with Multiple Co-Morbidities Have Delayed Viral Clearance: A Case Report from Bangladesh

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Infectious Diseases 2020年第3期10卷 94-100页

作者： md. Reaz Uddin Chowdhury Kazi Shanzida Akter Sahedul Islam Bhuiyan md. khalilur rahman Khabir Bimal Chandra Das Muhammad Anwarul Kabir Abdul Malek Ukil Medical College Noakhali Bangladesh Dedicated COVID-19 Hospital-Trauma Center Feni Bangladesh Brahmanbaria Medical College Brahmanbaria Bangladesh 250 Bed District Sadar Hospital Feni Bangladesh

Background: Novel corona virus (SARS-Coronavirus-2 SARS-CoV-2) which emerged in China has spread to multiple countries rapidly. Little information is known about delayed viral clearance in mild to moderate COVID-19 pa-tients. As it is highly contagious, health care workers including physicians are high risk of being infected in hospital care. Case Report: A 37 years old Bangladeshi physician working in a paediatric unit of a medical college hos-pital with multiple co-morbidities, hypertension, diagnosed axial spondy-loarthropathy (ankylosing spondylitis) taking disease modifying anti rheu-matic drugs— DMARDs (Salfasalazine) from 2016 till now, chronic persis-tent bronchial asthma on medication developed sore throat, increasing breathlessness and cough admitted to his own hospital on 22 April, 2020. He had a history of contact with a relapse nephrotic syndrome (glomerulone-phritis) patient admitted with severe respiratory distress later confirmed as COVID-19 following RT PCR test on 14 April, 2020. After 3 days of contact with the patient, the physician also developed the symptoms mentioned above. The RT PCR test result of the physician came positive on 18 April, 2020. The physician primarily taken only azithromycin 500 mg once daily along with other regular drugs. On 5, 12 and 18 May, 2020, his sample was taken for re-test and came positive subsequently. After that he started Iver-mectin (0.15 mg/kg) once daily for 3 days and doxycycline 100 mg BD for 7 days. He gave samples again on 27 and 29 May, 2020 which were came nega-tive after 39 days. On full recovery he was discharged from hospital on day 40. We choose the patient because presence of co-morbidities may be asso-ciated with delayed viral clearance and physicians with co-morbidities working in a hospital have high risk of being infected.

关键词： Physician Co-Morbidities Viral Clearance COVID-19 Case Report Bangla-desh

Computational Study on a Squid-Like Underwater Robot with Two Undulating Side Fins

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2011年第1期8卷 25-32页

作者： md. Mahbubar rahman Yasuyuki Toda Hiroshi Miki Department of Naval Architecture and Ocean Engineering Graduate School of Engineering Osaka University 2-1 Yamadaoka Suita City Osaka 565-0871 Japan

The undulating fin propulsion system is an instance of the bio-inspired propulsion systems. In the current study, the swimming motion of a squid-like robot with two undulating side fins, mimicking those of a Stingray or a Cuttlefish, was investigated through flow computation around the body. We used the finite analytic method for space discretization and Euler implicit scheme for time discretization along with the PISO algorithm for velocity pressure coupling. A body-fitted moving grid was generated using the Poisson equation at each time step. Based on the computed results, we discussed the features of the flow field and hydrodynamic forces acting on the body and fin. A simple relationship among the fin＇s principal dimensions was established. Numerical computation was done for various aspect ratios, fin angles and frequencies in order to validate the proposed relationship among principal dimensions. Subsequently, the relationship was examined base on the distribution of pressure difference between upper and lower surfaces and the distribution of the thrust force. In efficiency calculations, the undulating fins showed promising results. Finally, for the fin, the open characteristics from computed data showed satisfactory conformity with the experimental results.

关键词： biomimetics squid robot undulating fin propulsion efficiency hydrodynamics CFD

Efficient removal of heavy metals from electroplating wastewater using polymer ligands

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

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

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

在线全文

学校读者我要写书评

暂无评论

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

Infant and Under-five Mortality in Bangladesh: Discriminant Analysis

在线全文

学校读者我要写书评

暂无评论

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

Nutrient dynamics associated with leaf litter decomposition of three agroforestry tree species (Azadirachta indica, Dalbergia sissoo, and Melia azedarach) of Bangladesh

在线全文

学校读者我要写书评

暂无评论

Journal of Forestry Research 2011年第4期22卷 577-582页

作者： Mahmood Hossain Mohammad Raqibul Hasan Siddique md. Saidur rahman md. Zaber Hossain md. Mahedi Hasan Forestry and Wood Technology Discipline Khulna University Khulna - 9208 Bangladesh Soil Science Discipline Khulna University Khulna-9208 Forestry and Wood Technology Discipline Khulna University Khulna- 9208

Azadirachta indica A. Juss, Dalbergia, sissoo Roxb., and Melia azedarach L. are little studied species in nutrient return capabilities from leaf litter decomposition to maintenance of the soil fertility despite their importance in agroforestry practices of Bangladesh. A leaf litter decomposition experiment was conducted using a litterbag teeh7 nique to assess the nutrient reaun efficiency of these species. The de- composition rate of leaf litter was highest for M. azedarach and lowest for D. sissoo. Rainfall and temperature of study sites showed a significant （p〈0.05） positive relationship with the rate of leaf litter decomposition. The highest decay constant was observed for M. azedarach （6.67）. Nitrogen and Phosphorus concentration in leaf litter showed a decreased trend sharply at the end of the first month, whereas rapid decrease of Potassium concentration was reported within 10 days. Conversely, higher concentration of nutrient was observed at the later stages of decomposition. All three species showed a similar pattern of nutrient release （K 〉 N 〉 P） during the decomposition process of leaf litter. Among the studied species, D. sissoo was best in terms of N and P return and A. indica was best in terms of K return.

关键词： agroforestry decay constant decomposition leaf litter andnutrient dynamics

Can picnic influence floral diversity and vitality of trees in Bhawal National Park of Bangladesh?

在线全文

学校读者我要写书评

暂无评论

Forestry Studies in China 2009年第3期11卷 148-157页

作者： md. Mizanur rahman Harald VACIK Institute of Silviculture Department of Forest and Soil Sciences University of Natural Resources and Applied Life Sciences Vienna A-1190 Austria

We examined the impact of picnic activities on forest diversity, structure, regeneration and vitality of tree species in the Bhawal National Park of Bangladesh. The study area was classified as a non-used, occasionally used and frequently used area on the basis of the intensity of the picnic activities. A total of 43 plant species were enumerated in the whole study area. The highest plant species richness （41 species） was observed in the non-used area whereas the lowest species richness （11 species） in the frequently used area. The diversity index decreased with the increase of picnic intensity whereas the concentration of dominance increased. Density of all plant groups except mature trees, and the basal area of the mature trees showed a declining trend from the non-used to frequently used area. The frequently used area exhibited very poor regeneration. Tree vitality decreased with the increase of picnic intensity. The relevance of our study as a basis for further research to determine the impact of tourism on biodiversity in Bangladesh is discussed.

关键词： species richness diversity index concentration of dominance regeneration intensity