检索结果-南通市图书馆

A 0.9 V Supply OTA in 0.18 μm CMOS Technology and Its Application in Realizing a Tunable Low-Pass Gm-C Filter for Wireless Sensor Networks

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Circuits and Systems 2013年第1期4卷 34-43页

作者： Soolmaz Abbasalizadeh samad Sheikhaei Behjat Forouzandeh School of Electrical and Computer Engineering University of Tehran Tehran Iran

A low voltage low power operational transconductance amplifier (OTA) based on a bulk driven cell and its application to implement a tunable Gm-C filter is presented. The linearity of the OTA is improved by attenuation and source degeneration techniques. The attenuation technique is implemented by bulk driven cell which is used for low supply voltage circuits. The OTA is designed to operate with a 0.9 V supply voltage and consumes 58.8 μW power. A 600 mVppd sine wave input signal at 1 MHz frequency shows total harmonic distortion (THD) better than -40 dB over the tuning range of the transconductance. The OTA has been used to realize a tunable Gm-C low-pass filter with gain tuning from 5 dB to 21 dB with 4 dB gain steps, which results in power consumptions of 411.6 to 646.8 μW. This low voltage filter can operate as channel select filter and variable gain amplifier (VGA) for wireless sensor network (WSN) applications. The proposed OTA and filter have been simulated in 0.18 μm CMOS technology. Corner case and temperature simulation results are also included to forecast process and temperature variation affects after fabrication.

关键词： OTA Low Voltage Low Power Bulk Driven Gm-C Filter

MHD Free Convection Flow past an Inclined Stretching Sheet with Considering Viscous Dissipation and Radiation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Fluid Dynamics 2017年第2期7卷 152-168页

作者： Maruf Hasan Enamul Karim Abdus samad Department of Mathematics Comilla University Comilla Bangladesh Department of Applied Mathematics University of Dhaka Dhaka Bangladesh

The present study concentrates on the analysis of MHD free convection flow past an inclined stretching sheet. The viscous dissipation and radiation effects are assumed in the heat equation. Approximation solutions have been derived for velocity, temperature, concentration, Nusselt number, skin friction and Sherwood number using Nachtsheim-Swigert shooting iteration technique along with the six-order Runge-Kutta iteration scheme. Graphs are plotted to find out the characteristics of different physical parameters. The variations of physical parameters on skin friction coefficient, Nusselt number and Sherwood number are displayed via table.

关键词： Viscous Dissipation Magnetic Field Skin Friction Eckert Number

The Biphasic Role of Cupper and Counteraction with <i>Azospirillum brasilense</i>Application on Growth, Metabolities, Osmotic Pressure and Mineral of Wheat Plant

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

American Journal of Plant Sciences 2017年第5期8卷 1182-1195页

作者： Hamdia M. Abd El-samad Botany and Microbiology Department Faculty of Science Minia University El-Minia Egypt

The interactive effect of different Cu++ concentrations (5 mM, 10 mM, 20 mM and 25 mM) and treatments with biofertilizers Azospirillum brasilense on growth, metabolites, minerals and osmotic pressure of wheat plants was investigated. Shoots and roots of wheat plant were differentially response to Cu++ treatments, while shoot organ response positively to this treatment, root response negatively. The positive effect of Cu++ in shoot organ was concomitant with the increase in the production of fresh, dry matter, length and water content and this related with the accumulation of soluble sugar, soluble protein and mineral as a result of increasing osmotic pressure. On the other side, the negative effect of Cu++ on root organ was concomitant with the decrease in production of fresh, dry matter, length and water content that related with the reduction in the accumulation of soluble sugar and mineral with the insignificant change in osmotic pressure. Azospirillum brasilense inoculation increased the accumulation of soluble sugar and soluble protein which reflected an increase in the production of fresh, dry matter and water content with increasing values of osmotic pressure of the tested plants under Cu++ treatment. Finally, wheat plants response differentially to Cu++ treatment according to its organ and Azospirillum brasilense treatment improved wheat plant efficiency to tolerate the effect of Cu++ stress.

关键词： Cu++ Treatment Azospirillum brasilense Wheat

Effect of Brownian Diffusion on Squeezing Elastico-Viscous Nanofluid Flow with Cattaneo-Christov Heat Flux Model in a Channel with Double Slip Effect

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics 2020年第4期11卷 277-291页

作者： Md Enamul Karim Md Abdus samad Department of Applied Mathematics University of Dhaka Dhaka Bangladesh Department of Mathematics Comilla University Cumilla Bangladesh

The present study deals with the analysis of heat transfer of the unsteady Maxwell nanofluid flow in a squeezed rotating channel of a porous extensile surface subject to the velocity and thermal slip effects incorporating the theory of heat flow intensity of Cattaneo-Christov model for the expression of the energy distribution in preference to the classical Fourier’s law. A set of transformations is occupied to renovate the current model in a system of nonlinear ordinary differential equations that are numerically decoded with the help of MATLAB integrated function bvp4c. The effects of various flow control parameters are investigated for the momentum, temperature and diffusion profiles, as well as for the wall shearing stress and the heat and mass transfer. The results are finally described from the material point of view. A comparison of heat flux models of Cattaneo-Christov and Fourier is also performed. An important result from the present work is that the squeezing parameter is strong enough in the middle of the channel to retard the fluid flow.

关键词： Maxwell Fluid Model Squeezing Flow Elastico-Viscous Nanofluid Channel Rotation

在玻璃表面上短时接触硅藻土和多杀菌素对四纹豆象的致死效应和亚致死效应(英文)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

昆虫学报 2012年第11期55卷 1289-1294页

作者： Ehsan PARSAEYAN Moosa SABER samad VOJOUDI Department of Plant Protection Faculty of AgricultureUniversity of Maragheh Young Researchers Club Marand BranchIslamic Azad University

四纹豆象Callosobruchus maculatus(F.)是伊朗豇豆种子上的主要贮藏害虫。控制这一害虫时,用生物杀虫剂比用常规杀虫剂更为合适。本研究评价了室内条件下在玻璃表面上硅藻土和多杀菌素对四纹豆象成虫的致死效应和亚致死效应。结果表明:... 详细信息

四纹豆象Callosobruchus maculatus(F.)是伊朗豇豆种子上的主要贮藏害虫。控制这一害虫时,用生物杀虫剂比用常规杀虫剂更为合适。本研究评价了室内条件下在玻璃表面上硅藻土和多杀菌素对四纹豆象成虫的致死效应和亚致死效应。结果表明:硅藻土处理24h和48h后,对四纹豆象成虫的LC50值分别为1.47和0.2g/m2;多杀菌素处理24h和48h后,对四纹豆象成虫的LC50值分别为102.9和68.8mgai/L,说明两种化合物都对四纹豆象成虫具有较高的急性毒性。通过检测生物学参数,研究了LC20浓度的硅藻土和多杀菌素对四纹豆象的亚致死效应。LC20浓度的硅藻土和多杀菌素使四纹豆象成虫的繁殖力分别比对照降低了71.5%和17.2%,卵孵化率降低了57.5%和27.8%,成虫寿命缩短了74.7%和17.1%。接触LC20浓度的硅藻土和多杀菌素使这一害虫的蛹期分别比对照延长了4.8%和2.3%。亚致死效应研究表明,硅藻土和多杀菌素对四纹豆象的生命参数均产生了负面影响。总之,致死效应和亚致死效应综合显示,硅藻土在防治四纹豆象上具有较大的潜力。

关键词：四纹豆象生物杀虫剂生命参数致死效应亚致死效应

Development of mutants with varying flowering times by targeted editing of multiple SVP gene copies in Brassica napus L.

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The Crop Journal 2022年第1期10卷 67-74页

作者： Sunny Ahmar Yungu Zhai Huibin Huang Kaidi Yu Muhammad Hafeez Ullah Khan Muhammad Shahid Rana Abdul samad Shahid Ullah Khan Olalekan Amoo Chuchuan Fan Yongming Zhou National Key Laboratory of Crop Genetic Improvement Huazhong Agricultural UniversityWuhan 430070HubeiChina

Manipulation of flowering time to develop cultivars with desired maturity dates is fundamental in plant *** is desirable to generate polyploid rapeseed(Brassica napus L.)germplasm with varying flowering time controlled by a few *** the present study,Bna SVP,a rapeseed homolog of the Arabidopsis SVP(Short Vegetative Phase)gene,was characterized and a set of mutants was developed using a CRISPR/Cas9-based gene-editing tool.A single construct targeting multiple sites was successfully applied to precisely mutate four copies of Bna *** induced mutations in these copies were stably transmitted to subsequent *** mutants with loss-of-function alleles and free transgenic elements were generated across the four Bna SVP *** mutant T_(1)lines tested in two environments(summer and winter growing seasons)showed early-flowering *** decrease in flowering time was correlated with the number of mutated Bna SVP *** quadruple mutants showed the shortest flowering time,with a mean decrease of 40.6%–50.7%in length relative to the wild type under the two growth *** study demonstrates the quantitative involvement of Bna SVP copies in the regulation of flowering time and provides valuable resources for rapeseed breeding.

关键词： Brassica napus Flowering time BnaSVP Gene editing

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

中巴民用核能合作及其对巴基斯坦经济的影响

中巴民用核能合作及其对巴基斯坦经济的影响

作者： Abdul samad Prince 中国海洋大学

学位级别：硕士

世界各国对电力的需求正在日渐增长,巴基斯坦也不例外。目前,巴基斯坦正在竭尽全力解决国内的能源危机。能源需求剧增的原因是大规模的工业扩张和经济发展,敦促着人们需求可持续发展的能源需求解决方案。事实上,在贫穷人数少于5%的发达... 详细信息

世界各国对电力的需求正在日渐增长,巴基斯坦也不例外。目前,巴基斯坦正在竭尽全力解决国内的能源危机。能源需求剧增的原因是大规模的工业扩张和经济发展,敦促着人们需求可持续发展的能源需求解决方案。事实上,在贫穷人数少于5%的发达国家,人们的能源消费相比贫穷人口占多数的国家人们的能源消费要多得多。这说明,电力是经济可持续发展的重要支柱。本文将就中巴核电合作对巴基斯坦经济的影响进行研究,并就目前发电技术危机对巴基斯坦的影响提出见解。然后,本文将对中国的电力部门进行简单介绍,并提出提高巴基斯坦发电能力的建议。本文由九部分组成,带领读者从零开始建立对行业的理解,并提出问题的解决方法。本文的第一部分包括背景介绍,文献综述,大纲和框架,研究方法和创新。通过对中巴之前和目前的民用核电合作的分析,和对广大学者的意见综述,本文认为电力部门的信息源是非常总要的。这一部分的重要目标是为当前的合作提供建议。本文的第二部分主要介绍了关于国际合作的定义和基本理论。这些理论包括不同学者在两国不同领域合作的研究。为后文的研究提供了理论基础。这一部分也会介绍后文研究合作对巴基斯坦经济的影响所使用的研究方法。本文的第三部分主要是介绍巴基斯坦电力部门现状和经济状况,并且会给出电力部门组织结构和发电技术的定义。这一章会对电力危机现状进行简单介绍并分析其对巴基斯坦经济的影响,同时,本章将会分析电力部门的主要问题和发电技术的重要性。本文的第四部分是关于中国电力部门发展的案例研究,并会对中国发电技术进行简单介绍。这一章会分析中国在经济发展过程中所遇到的问题。本章进行案例分析的目的是为巴基斯坦电力部门的发展提供建议,促进其平稳健康发展。本文的第五部分介绍的是中巴之间正在进行的民用核电合作。这一章将对合作的目的,背景,合作发展前景和预期收益进行分析。本文的第六部分通过计量分析的方法研究中巴合作对巴基斯坦经济的影响。本文的第七部分对核能的经济和环境影响进行了研究,并分析了环境和经济两者之间的关系。这一部分将以福岛核电站泄漏事件作为分析案例。本文的第八部分主要是提出意见和建议。本文的第九部分是结论与展望。这一部分对全文进行了总结,并且指出了未来的研究方向。

关键词：中巴合作经济影响民用核能发电

二氧化钛纳米粒子催化合成Hantzsch酯和多氢喹啉衍生物(英文)

同方学位论文库评论

在线全文

同方学位论文库

学校读者我要写书评

暂无评论

催化学报 2012年第9期33卷 1517-1522页

作者： Mahmood TAJBAKHSH Ehsan ALAEE Heshmatollah ALINEZHAD Mohammad KHANIAN Fatemeh JAHANI samad KHAKSAR Parizad REZAEE Mahgol TAJBAKHSH Department of Organic Chemistry Faculty of ChemistryUniversity of Mazandaran Gorgan Medical University Chemistry Department Islamic Azad University

1,4-Dihydropyridine and polyhydroquinoline derivatives have been prepared efficiently in a one-pot synthesis via Hantzsch condensation using nanosized titanium dioxide as a heterogeneous *** present methodology offers several advantages such as excellent yields,short reaction times (30-120 min),environmentally benign,and mild reaction *** catalyst can be readily separated from the reaction products and recovered in excellent purity for direct reuse.

关键词： titanium dioxide nanoparticles Hantzsch reaction 1,4-dihydropyridine polyhydroquinoline

基于有限元方法的稳压器波动管热应力特性分析

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

基于有限元方法的稳压器波动管热应力特性分析

作者： Muhammad Abdus samad 华北电力大学(北京)

学位级别：硕士

热分层是不同温度的流体在同一结构中共存的现象。温度高、密度小的流体位于上层,同理,温度低的流体位于下层。由于顶部和底部热膨胀差,导致了流体结构的显著变形。在热电厂中,一般情况下管道是被固定的,因此热分层引起的变形会导致管... 详细信息

热分层是不同温度的流体在同一结构中共存的现象。温度高、密度小的流体位于上层,同理,温度低的流体位于下层。由于顶部和底部热膨胀差,导致了流体结构的显著变形。在热电厂中,一般情况下管道是被固定的,因此热分层引起的变形会导致管道发生意想不到的移动,从而在管道的轴向、周向和径向产生过大的应力,这可能会超过疲劳和应力的设计极限。本文利用 CFD软件(ANSYS CFX)和有限元求解程序(ANSYS MECHANICAL)对压水堆稳压器波动管线进行了分析。首先在ICEM软件中设计了波动管线网格模型,并在稳态分析中对其性能进行了测试。选用对变化最不敏感的网格模型,并将温度曲线导入到有限元求解程序中。它们的结构分析代码用于确定施加在管道上的热应力以及结构的响应特性。此外,在瞬态热分析中还研究了喘振工况下波动管线的温度分布。结果表明,在主管道和稳压器的边界存在较大的稳态应力,应力引起的管道形变使波动管线的中心产生了较大的位移。另外,根据本文所评估的瞬态温度曲线,还计划计算出波动管充满热水时的瞬态情况下的应力分布。

关键词：稳压器波动管流固耦合热应力 ANSYS CFD分析