检索结果-南通市图书馆

Flow Diagnosis and Optimization Based on Vorticity Dynamics for Transonic Compressor/Fan Rotor

Open Journal of Fluid Dynamics 2017年第1期7卷 40-71页

作者： Huanlong Chen Mark G. Turner Kiran Siddappaji syed Moez hussain Mahmood Institute of Propulsion Theory and Technique Harbin Institute of Technology Harbin China Aerospace Engineering Department University of Cincinnati Cincinnati OH USA

This paper presents two optimized rotors. The first rotor is as part of a 3-blade row optimization (IGV-rotor-stator) of a high-pressure compressor. It is based on modifying blade angles and advanced control of curvature of the airfoil camber line. The effects of these advanced blade techniques on the performance of the transonic 1.5-stage compressor were calculated using a 3D Navier-Stokes solver combined with a vortex/vorticity dynamics diagnosis method. The first optimized rotor produces a 3-blade row efficiency improvement over the baseline of 1.45% while also improving stall margin. The throttling range of the compressor is expanded largely because the shock in the rotor tip area is further downstream than that in the baseline case at the operating point. Additionally, optimizing the 3-blade row block while only adjusting the rotor geometry ensures good matching of flow angles allowing the compressor to have more range. The flow diagnostics of the rotor blade based on vortex/vorticity dynamics indicate that the boundary-layer separation behind the shock is verified by on-wall signatures of vorticity and skin-friction vector lines. In addition, azimuthal vorticity and boundary vorticity flux (BVF) are shown to be two vital flow parameters of compressor aerodynamic performance that directly relate to the improved performance of the optimized transonic compressor blade. A second rotor-only optimization is also presented for a 2.9 pressure ratio transonic fan. The objective function is the axial moment based on the BVF. An 88.5% efficiency rotor is produced.

关键词： Transonic Compressor Control Curvature Optimization Vorticity Dynamics BVF Azimuthal Vorticity

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Potential Antioxidant Activities Improve Salt Tolerance in Ten Varieties of Wheat (<i>Triticum aestivum</i>L.)

引用

American Journal of Plant Sciences 2013年第6期4卷 69-76页

作者： Aurangzeb Rao syed Dilnawaz Ahmad syed Mubashar Sabir Shahid Iqbal Awan Asad hussain Shah syed Rizwan Abbas Saima Shafique Fareed Khan Atia Chaudhary Department of Chemistry University of the Poonch Rawalakot Pakistan. Department of Plant Breeding and Molecular Genetics Faculty of Agriculture University of the Poonch Rawalakot Pakistan Department of Plant Breeding and Molecular Genetics Faculty of Agriculture University of the Poonch Rawalakot Pakistan University of Azad Jammu and Kashmir Muzaffarabad Pakistan

The activity of antioxidative enzymes system is affected by salt stress, chlorophyll content (CHL), leaf relative water content (RWC), Na+ and K+ contents, their ratio and some oxidative stress indices were studied in leaves of ten bread wheat cultivarsSehar-06, Lu-26, NARC-09, BARC-09 and Pirsbak-09’(salt-tolerant) and Kaghan-94, Rohtas-90, Soughat-90, Shaheen-94 and Zardana-89’(salt-sensitive), grown under salinity treatments carried out in five levels (1 dS·m-1 as control, 2, 4, 8, 16 dS·m-1) via sodium chloride. Under high salt potency significant increase for activities of antioxidant enzymes such as ascorbate peroxidase (APX) and guiacol peroxidase (GPX), occured in salt tolerant varieties. Meanwhile, under salinity condition the activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and (GPX) in sensitive cultivar were lower than control. Regarding (APX) activity there was no significant difference between salinity and control situation. Under salt stress membrane stability index (MSI) of both cultivars were negatively influenced. Hydrogen peroxide (H2O2) content of salinity sensitive cultivars was higher than control. Salt tolerant varieties had more amounts of K+ content, K+ and Na+ ratio, relative water content, yield and chlorophyll under salt conditions, and sensitive ones recorded higher Na+ content at tillering stage. The mechanism of salt stress might be achieved due to low lipid peroxidation, assumingly lower changes in membrane stability index and evasion of Na+ combination and amplified activity of antioxidant enzymes.

关键词： Antioxidant Enzymes Chlorophyll Content+/Na+ Ratio Relative Water Content Salinity Wheat

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Hepatoprotective effect of leaves of Erythroxylum monogynum *** paracetamol induced toxicity

引用

Asian Pacific Journal of Tropical Biomedicine 2013年第11期3卷 877-881页

作者： Sabeena hussain syed Ajay Gajanan Namdeo Department of Pharmacognosy Bharati Vidyapeeth Deemed UniversityPoona College of Pharmacy

Objective:To investigate the hepatoprotective activity of methanolic extract of leaves of Erythroxylum monogynum(***)on paracetamol induced ***:Methanolic extract of leaves of *** was given in doses of 100 mg/kg,200 mg/kg and 400 mg/kg for 7 d and toxicity was induced by paracetamol(2 mg/kg)on Day ***(50 mg/kg)was used as reference *** 24 h of toxicity induction blood samples were collected from retro-orbital plexsus and analyzed for serum parameters like serum glutamic pyruvic transaminase,serum glutamic oxaloacetate transaminse,alkaline phosphatase and total *** isolated were studied for histopathological ***:Phytochemical analysis of methanolic extract of *** leaves showed the presence of carbohydrates,flavonoids,phenols and *** administration of this extract restored the elevated levels serum markers as compared to toxic group which is also confirmed by the histopathological changes ***:The present study showed that methanolic extract of leaves of *** possess hepatoprotective action against paracetamol induced hepatotoxicity.

关键词： Erythroxylum monogynum Hepatoprotection Paracetamol Silymarin

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

腾格里沙漠盐湖氯同位素地球化学特征

引用

湖泊科学 2018年第4期30卷 1157-1165页

作者：韩凤清毛庆飞马茹莹张燕霞孙宇强韩继龙年秀清刘文玉 syed Asim hussain 马喆中国科学院青海盐湖研究所中国科学院盐湖资源综合高效利用重点实验室西宁810008 青海省盐湖地质与环境重点实验室西宁810008 中国科学院大学北京100049 青海省地震局西宁810001 宁夏回族自治区地震局银川750001 青海民族大学西宁810007

δ^(37)Cl值可以用来指示盐湖演化过程中卤水的蒸发浓缩程度、可能的补给来源和控制因素,本文对腾格里沙漠地区12个代表性盐湖卤水样品开展了氯同位素组成研究.结果表明,研究区内沙漠盐湖卤水的δ^(37)Cl值变化范围为-0.10‰~1.36‰,平... 详细信息

δ^(37)Cl值可以用来指示盐湖演化过程中卤水的蒸发浓缩程度、可能的补给来源和控制因素,本文对腾格里沙漠地区12个代表性盐湖卤水样品开展了氯同位素组成研究.结果表明,研究区内沙漠盐湖卤水的δ^(37)Cl值变化范围为-0.10‰~1.36‰,平均值为0.55‰;其中,硫酸钠亚型卤水的δ^(37)Cl值范围为-0.10‰~1.36‰(平均值为0.56‰),硫酸镁亚型卤水的δ^(37)Cl值范围为0.14‰~0.82‰(平均值为0.48‰).对比柴达木盆地现代盐湖分析数据,发现区内沙漠盐湖的δ^(37)Cl平均值明显大于柴达木盆地盐湖的δ^(37)Cl平均值,并且,硫酸钠亚型卤水δ^(37)Cl最高,硫酸镁亚型卤水次之,氯化物型卤水最小.基于不同盐湖地下水咸化程度以及盐湖卤水中δ^(37)Cl值与Br/Cl系数关系的研究,揭示了研究区东部和东北部盐湖可能受到第三系地层咸水的补给,而其他盐湖主要受蒸发浓缩作用影响.δ^(37)Cl值分布特征则显示,腾格里沙漠地区部分盐湖在形成过程中可能受到区域构造活动诱发的第三系深部水补给及水-岩作用等多重因素的影响.

关键词：氯同位素盐湖卤水腾格里沙漠

来源：

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

Simultaneous Quantification of Ibuprofen and Paracetamol in Tablet Formulations Using Transmission Fourier Transform Infrared Spectroscopy

引用

American Journal of Analytical Chemistry 2012年第8期3卷 503-511页

作者： Muhammad Ali Mallah syed Tufail hussain Sherazi Sarfaraz Ahmed Mahesar Abdul Rauf Khaskheli National Center of Excellence in Analytical Chemistry University of Sindh Jamshoro Pakistan

A very simple, non-destructive, inexpensive and green strategy was applied for the simultaneous determination of ibu-profen (IBP) and paracetamol (PC) using transmission Fourier Transform Infrared (FTIR) spectroscopy in tablet formulations for routine quality control laboratories. For the determination of the active pharmaceutical ingredients (API), KBr pellets containing known amount of standards and samples were used for acquisition of the FTIR spectra. The partial least squares (PLS) calibration model was developed using the spectral region from 1781 - 1683 cm-1 for IBP and 1630 - 1530 cm-1 for PC. The excellent coefficients of determination (R2), 0.9999 and 0.9998 were achieved for IBP and PC, respectively. The accuracy of calibration model was also verified through root mean square error of cross validation (RMSECV) which was found to be 0.064. This work clearly shows the capability of transmission FTIR spectroscopy for assessment of exact quantity of API to control the quality of finished products as well as during processing in pharmaceutical industries without involvement of any solvent.

关键词： Transmission FTIR Pharmaceutical Formulation Ibuprofen Paracetamol Simultaneous Determination Quantitative Analysis

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Adsorption and Leaching Potential of Imidacloprid Pesticide through Alluvial Soil

引用

American Journal of Analytical Chemistry 2012年第8期3卷 604-611页

作者： Muhammad Ashraf Bajeer Shafi Muhammad Nizamani syed Tufail hussain Sherazi Muhammad Iqbal Bhanger National Center of Excellence in Analytical Chemistry University of Sindh Jamshoro Pakistan

This study was aimed to assess the adsorption and leaching potential of imidacloprid pesticide in column and field soil. To visibly understand these actions and factors affecting them, the experiments were carried out under laboratory and field conditions. Adsorption study was divided into kinetic and equilibrium sections. The evaluation of kinetic data was done through pseudo first and second order models. It was found that kinetic adsorption of imidacloprid on soil followed pseudo second order with rate constant value of 4.333 mg/g/h. Langmuir and Freundlich isotherms were used to explain equilibrium adsorption, from these isotherms it was evaluated that Freundlich isotherm was obeyed well with adsorption capacity of 2.190 - 4.573 mol/g. Leaching study was performed in laboratory using column made of poly-vinyl chloride having 30 cm length. Known amount of imidacloprid pesticide was applied to column left for adsorption and then eluted with 500 mL water in five equal portions. These water portions and soil of column which was divided into three sections were analyzed by HPLC. The result revealed that the concentration of imidacloprid was decreased from 0.481 ppm in first portion of water to 0.327 ppm in last portion of water while 0.783 ppm in first section of column soil to 0.038 ppm in last section of column soil. In field the leaching power of imidacloprid was observed up to 60 cm depth, its concentration decreased with soil depth. It was 3.311 ppm in first portion of soil and 0.357 ppm in last portion of soil. The leaching potential of imidacloprid pesticide up to 60 cm soil depth was due to less organic matter, sandy texture, alkaline pH, and low cation exchange capacity.

关键词： Pesticide Adsorption Leaching Imidacloprid Soil

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Effects of antibiotic on the bacterial microflora in two commercially important catfish species,Clarias batrachus and Heteropneustes fossilis in Bangladesh

引用

Journal of Coastal Life Medicine 2014年第11期 845-848页

作者： Md.Shahdat Hossain Md.Rajib Sharker syed Ariful Haque Md.shaheed Reza Md.Anwar Hossain Mondal Department of Fisheries Technology Faculty of FisheriesBangladesh Agricultural UniversityMymensingh 2202Bangladesh Department of Fisheries Biology and Genetics Patuakhali Science and Technology UniversityDumkiPatuakhaliBangladesh Department of Fisheries Technology Sheikh Fajilatunnesa Mujib Fisheries CollegeMelandahJamalpurBangladesh Department of Fisheries Technology Bangladesh Agricultural UniversityMymensingh 2202Bangladesh Department of Aquaculture Patuakhali Science and Technology UniversityDumkiPatuakhaliBangladesh

Objective:To assess the effects of a widely used antibiotic,oxytetracycline(OTC)on the bacterial microflora in two catfish species under artificial culture conditions in the ***:The experiment was conducted in the Faculty of Fisheries,Bangladesh Agricultural University,*** fish were reared in six aquaria(size 37 cm×30 cm×60 cm)where three aquaria served as replicates of the antibiotic treatment groups and the remaining three aquaria served as an untreated control *** aquarium was stocked with 25 fish on an average body weight 15 *** was administered to the fish in the treatment groups at the rate of 2 g/kg in-feed twice daily upto ad libitum,whereas fish in the untreated control groups were given the same feed without antibiotics for 20 *** the experiment,bacterial loads were estimated as colony forming unit(CFU/g)by every alternate day in the aquarium water,gills,skin and intestine of ***:The administration of OTC in feed resulted in gradual decrease of bacterial loads in the gills,intestine and skin of the two catfish species *** contrast,the bacterial loads remain unchanged or slightly increased in the control groups not fed with *** quality parameters such as dissolved oxygen,pH and total hardness were found to be within suitable range in the test aquaria but not in control aquarium throughout the experimental ***:The results of this experiment showed that in-feed antibiotic OTC for a period of 20d reduced the bacterial loads in the gills,intestines and skin of treated fish.

关键词： Antibiotic therapy Bacterial load Catfish

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Modeling transmission dynamics of Ebola virus disease

引用

International Journal of Biomathematics 2017年第4期10卷 297-331页

作者： Mudassar Imran Adnan Khan Ali R. Ansari syed Touqeer hussain Shah International Center for Applied Mathematics and Computational Bioengineering Department of Mathematics and Natural Sciences Gulf University for Science and Technology Hawally Kuwait Department of Mathematics Lahore University of Management Sciences Lahore Pakistan

Ebola virus disease (EVD) has emerged as a rapidly spreading potentially fatal disease. Several studies have been performed recently to investigate the dynamics of EVD. In this paper, we study the transmission dynamics of EVD by formulating an SEIR-type transmission model that includes isolated individuals as well as dead individuals that are not yet buried. Dynamical systems analysis of the model is performed, and it is consequently shown that the disease-free steady state is globally asymptotically stable when the basic reproduction number, ℛ 0 is less than unity. It is also shown that there exists a unique endemic equilibrium when ℛ 0 > 1 . Using optimal control theory, we propose control strategies, which will help to eliminate the Ebola disease. We use data fitting on models, with and without isolation, to estimate the basic reproductive numbers for the 2014 outbreak of EVD in Liberia and Sierra Leone.

关键词： Ebola virus disease endemic equilibrium basic reproduction number hospitalization infectiousness optimal control transmission dynamics time series data fitting

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

乙二胺四乙酸二钠用于沉积物酸溶相中高精度硼同位素测定方法研究

引用

分析化学 2019年第9期47卷 1433-1439页

作者：杨剑马云麒李兴意刘玉秀韩风清张艳灵 syed Asim hussain 李海军中国科学院青海盐湖研究所中国科学院盐湖资源综合高效利用重点实验室青海省盐湖地质与环境重点实验室中国科学院大学中国科学院青海盐湖研究所盐湖化学分析测试中心

采用传统的酸溶法进行沉积物样品（包括粘土样品或碳酸盐等样品）硼同位素测定的前处理过程中,酸通常会溶解出样品中大量Ca;、Fe;、Mg;、Al;等金属离子以及稀土元素。由于前处理过程中溶出的硼只有在碱性环境中才能被硼特效树脂有效地吸... 详细信息

采用传统的酸溶法进行沉积物样品（包括粘土样品或碳酸盐等样品）硼同位素测定的前处理过程中,酸通常会溶解出样品中大量Ca;、Fe;、Mg;、Al;等金属离子以及稀土元素。由于前处理过程中溶出的硼只有在碱性环境中才能被硼特效树脂有效地吸附,而大量共存的Ca;、Fe;、Mg;、Al;等金属离子在碱性条件下会产生难溶于水的氢氧化物沉淀,进而会造成硼的丢失和同位素分馏。本研究在沉积物酸溶相样品中加入适量EDTA-2Na饱和溶液,再将样品溶液调成碱性,能有效抑制沉淀的产生。用氨水淋洗吸附后的硼特效树脂,并延长样品电离时间,能有效降低EDTA-2Na对硼同位素测定的干扰,从而达到样品中硼元素的高效提取和硼同位素组成的准确测定。结果表明,样品加入EDTA-2Na饱和溶液后硼的回收率可达到95%以上。同时,经过处理后的NIST SRM 951硼酸标准样品的;B/;B比值在4.05146～4.05628之间;三亚沉积物、大柴旦湖心沉积物和大柴旦湖心晶间卤水沉积物的硼同位素组成(δ;B)分别为+17.64‰、-5.74‰和+1.8‰。本方法可满足沉积物样品（如粘土沉积物、碳酸盐沉积物、黄土、古土壤等样品）酸溶相中硼同位素组成高精度测定的要求,为此类样品的高精度硼同位素测定提供了一种简单、低干扰的前处理方法。

关键词：沉积物酸溶相氢氧化物沉淀乙二胺四乙酸二钠硼同位素热电离质谱

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Application of Remote Sensing and GIS in Forest Cover Change in Tehsil Barawal, District Dir, Pakistan

引用

American Journal of Plant Sciences 2015年第9期6卷 1501-1508页

作者： Anwar Sajjad Ahmad hussain Umar Wahab syed Adnan Saqib Ali Zahoor Ahmad Ashfaq Ali Department of Environmental Sciences University of Haripur Haripur Pakistan Department of Forestry and Wildlife University of Haripur Haripur Pakistan Institute of Geographical Information Systems National University of Sciences and Technology (NUST) Islamabad Pakistan Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory College of Plant Science and Technology Huazhong Agricultural University Wuhan China Department of Plant Pathology College of Plant Science and Technology and the Key Lab of Crop Disease Monitoring & Safety Control in Hubei Province Huazhong Agricultural University Wuhan China College of Horticulture and Forestry Sciences Huazhong Agriculture University Wuhan China

The forests of Pakistan replicate plentiful climatic, physiographic and edaphic differences in the country and these forests face a serious problem of deforestation. Geographic information system (GIS) techniques and remote sensing (RS) from satellite platforms offer a best way to identify those areas of deforestation, and thus a GIS and RS based study was conducted in tehsil Barawal, district Dir (U) to analyze forest cover change. The main objectives of the study were to: 1) identify different classes of land use and land cover, and its spatial distribution in the study area;2) determine the trend, nature, location and magnitude of forest cover change;and 3) prepare maps of forest-cover change in different time periods in the study area. To assess the objectives remote sensing and GIS techniques were utilized. A supervised image classification technique was applied on Landsat 5 satellite images of 2000 and 2012. Five main classes such as agriculture, forest, barren land, snow and water were identified. The results showed that the area of forest, barren land, agriculture, water and snow in year 2000 was 49.54%, 43.38%, 5.19%, 1.40% and 0.49% and the area in 2012 was 37.17%, 41.36%, 12.69%, 5.05% and 3.72% respectively. Furthermore 2.02% decrease in barren land, 12.37% decrease in forest and 7.5% increase in agriculture land were identified. Due to high deforestation rate and increased agricultural activities, it is recommended that awareness campaign should be launched in the study area to protect and conserve this forest from further deforestation.

关键词： Deforestation Change Analysis Forest Cover Change

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：