检索结果-南通市图书馆

Open Journal of Applied Sciences 2017年第9期7卷 458-484页

作者： Abdul Rauf Shah Hajira Tahir Hafiz muhammad Kifayat Ullah Asma Adnan Department of Chemistry University of Karachi Karachi Pakistan

The study was useful for the treatment of Reactive red 223 (R223) and Coomassie brilliant blue R250 (CBBR250) binary dye system by electrocoagulation process (EC). Moreover, the Al and Fe electrode were used as an anode and cathode, respectively. The response surface methodology (RSM) was adopted by utilizing central composite design to plan the experimental runs. The EC process was preceded under the effect of operating parameters including pH, NaCl, voltage and electrolysis time. The % color and COD removals were examined as response variables. The removal efficiency of RR223 and CBBR250 dye at optimum values was 89% and 94% and COD removal was 100%. The kinetic study was performed to determine the rate and rate constant. First and second order kinetic models were studied to figure out the exact mechanism of the dye removal using EC process. The estimated cost of the experimental design about 4.486 US$/dm3 was also determined. This study showed that EC process is an economical way for the treatment of waste water.

关键词： Electrocaogulation Central Composite Design Kinetic Study FTIR Color COD

基于永磁同步风力发电系统的功率变换器故障容错控制

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

基于永磁同步风力发电系统的功率变换器故障容错控制

作者：诺曼（muhammad NOMAN）东南大学

学位级别：硕士

风能和太阳能资源是最受欢迎的可再生能源。这两种能源都有许多优点,比如它们取之不尽用之不竭并且清洁。这种优势使得可再生能源在全球市场受到欢迎。考虑到安装成本,与太阳能相比,风能系统的成本更低。风能系统的主要问题是它的供给... 详细信息

风能和太阳能资源是最受欢迎的可再生能源。这两种能源都有许多优点,比如它们取之不尽用之不竭并且清洁。这种优势使得可再生能源在全球市场受到欢迎。考虑到安装成本,与太阳能相比,风能系统的成本更低。风能系统的主要问题是它的供给是不固定的。因此,风能系统的使用需要得到其他能源的支持作为补充。随着风能市场发展,风能转换系统(WECSs)的成本和可靠性问题已经变得越来越重要。风能转换系统意外关机的问题可能导致重大的经济损失,因此需要花费了大量的检查和维护费用。大多的WECSs安装在偏远地区并且建在高塔上。大多数的风能转换系统使用PMSG作为驱动电机,这样的系统具有高功率密度和高效率的优点。WECSs很容易出现各种故障,任何故障都有可能导致系统对能源生产的巨大损失。如果变换器的某一桥臂发生故障,系统关闭,在这种情况下,背靠背变换器将切换到容错控制模式,避免了系统的突然停机,并在另外变换器五条桥臂下继续工作。本文对基于WECS的直驱PMSG系统进行了建模、控制和仿真。该系统能够从风场获取最优功率。本文对PMSG系统的两种工作模式进行比较和分析。为了跟踪风力发电系统的最大功率,并考虑风力机的非线性特性,采用了基于最大叶尖速比的最大功率点跟踪技术,包括了电池和俯仰角控制,以获得最大输出。对传统的五桥臂和六桥臂变换器进行了比较和仿真。在故障情况下,为提高系统可靠性、健壮性、效率、使用性和连续性,采用了基于故障容错控制模式下五桥臂变换器。提出了具有相同性能的五桥臂变换器拓扑,以取代传统的六桥臂变换器。

关键词：五桥臂变换器永磁同步发电机风能转换系统容错控制

蚯蚓粪配施化肥对番茄农艺性状、品质和土壤理化性质的影响

在线全文

同方学位论文库

学校读者我要写书评

暂无评论

蚯蚓粪配施化肥对番茄农艺性状、品质和土壤理化性质的影响

作者：穆柯（muhammad Qasim）扬州大学

学位级别：硕士

番茄是世界上产量第三大的蔬菜。由于化肥不合理施用会导致番茄农田土壤营养成分流失、结构不良、微生物数量减少等土壤问题,进而导致番茄的产量和品质的降低。增施有机肥能有效改良土壤理化性质,提高番茄的产量和品质。在众多有机肥中... 详细信息

番茄是世界上产量第三大的蔬菜。由于化肥不合理施用会导致番茄农田土壤营养成分流失、结构不良、微生物数量减少等土壤问题,进而导致番茄的产量和品质的降低。增施有机肥能有效改良土壤理化性质,提高番茄的产量和品质。在众多有机肥中,蚯蚓粪能将有机物、微生物及作物的生长因子有效结合起来,在土壤保水保肥,提高蔬菜品种果蔬提质增产方面表现更为突出。基于此,与2021-2022年在巴基斯坦信德省坦多贾姆农场开展本研究,采用随机完全区组设计6个处理,每个处理重复四次,T1=N:P(100:50 kg ha-1),T2=N:P:K(100:50:50 kg ha-1),T3=Vermicompost 1(2t ha-1),T4=Vermicompost 2(2t ha-1),T5=N:P:K+Vermicompost 1(50:25:25 kg ha-1+1.5 tha-1)and T6=N:P:K+Vermicompost2(50:25:25 kg ha-1+1.5 tha-1),研究蚯蚓粪单施和蚯蚓粪配施化肥对番茄生长、产量和品质及改良土壤理化性质的影响,结果表明:(1)与NP单施(T1)处理相比,蚯蚓粪1配施NPK肥料(T5)处理有效改善了番茄植株的根长、根鲜重和干重、株高、地上部鲜重和干重、SPAD值、叶绿素“a”、“b”及总叶绿素含量、相对含水量、膜稳定性指数、光合速率、类胡萝卜素含量分别增加21.6%、45.13%、46.2%、168%、39%、44%、13.5%、96%、155%,109%、17%、16%、89 和150%。本研究考察了不同剂量和组合的VC和无机肥料对番茄植株生长和生理特性的影响。我们得出结论,与单独施用有机和无机肥料相比,VC和NPK肥料的联合施用显着影响植物生理和形态特征。(2)与NP单施(T1)处理相比,蚯蚓粪1配施NPK肥料(T5)处理有效地提高了番茄产量、果实长度和果实的直径,分别提高的幅度为88%、101%、83%。我们的结论是,与单独施用有机和无机肥料相比,两种类型的VC与NPK施肥的结合增加了番茄产量特征(果实长度、直径和产量)。(3)与NP单施(T1)处理相比,蚯蚓粪1配施NPK肥料(T5)处理有效提高了番茄的营养品质,蛋白质、维生素C、钙、镁、磷、钾含量,分别提高了 89%、52%、55%、117%、38%和128%。我们观察到,与单独施用有机和无机肥料相比,两种类型的VC与NPK施肥相结合的应用增强了番茄果实的各种营养分析。(4)与处理前土壤理化指标相比,各处理均改善了处理后土壤理化指标。蚯蚓粪单施和蚯蚓粪配施NPK肥均显著改善了土壤的理化参数,以蚯蚓粪1单施(T3)处理比NPK单施及蚯蚓粪配施NPK处理改善效果最好。蚯蚓粪1单施(T3)处理下,土壤有机质含量(2.15%)、N 含量(0.147%)、有效 P 含量(2.50 mg kg-1)和可交换 K 含量(98.3 mg kg-1)的含量最高。与其他处理相比,NP肥料单施(T1)处理下土壤理化性质各参数最低。得出的结论是,与常规肥料及其单独和联合处理相比,单独施用蚯蚓粪在改善土壤特性方面产生了更显着的结果。

关键词：蚯蚓粪土壤理化性质番茄生长产量和品质

Application of Hoof Tillage Method to Improve Degraded Mountain Grassland

在线全文

同方学位论文库

学校读者我要写书评

暂无评论

Animal Husbandry and Feed Science 2015年第2期7卷 131-134,F0003页

作者： Yimin Sidik Li Xuesen Munire muhammad Jianati Mikesh Jiang Runxiao Institute of Grassland Science Xinjiang Academy of Husbandry Science

Four seeding methods, including broadcast sowing, feeding seeds to sheep, putting seed bag on sheep and cattle, and mix-seeding were combined with hoof tillage method to improve the degraded mountain grassland where large gradient limited the use of machine. The results showed that the most suitable grassland type for hoof tillage was mountain meadow steppe. The optimum reseeding period was early spring, followed by late autumn ; and Sainfoin （Onobrychis sativa） was the most suitable herbage species. The optimum reseeding method was artificial broadcasting in the slope with the gradient 〈 20°, followed by putting seed bag on sheep and cattle. After improvement of hoof tillage, the vegetation coverage increased by 35%, the proportion of high quality herbage increased by 25%, and the fresh yield increased by three to four times.

关键词： Hoof tillage Degraded grassland Suitable grass species Improvement method

Environmental risk factors for inflammatory bowel diseases: Evidence based literature review

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2016年第27期22卷 6296-6317页

作者： Ayokunle T Abegunde Bashir H muhammad Owais Bhatti Tauseef Ali Section of Digestive Diseases and Nutrition Department of Medicine Oklahoma University Health Sciences Center Department of Medicine Oklahoma University Health Sciences Center

AIM: To advances in genetics and immunology have contributed to the current understanding of the pathogenesis of inflammatory bowel diseases(IBD). METHODS: The current opinion on the pathogenesis of IBD suggests that genetically susceptible individuals develop intolerance to dysregulated gut microflora(dysbiosis) and chronic inflammation develops as a result of environmental insults. Environmental exposures are innumerable with varying effects during the life course of individuals with IBD. Studying the relationship between environmental factors and IBD may provide the missing link to increasing our understanding of the etiology and increased incidence of IBD in recent years with implications for prevention, diagnosis, and treatment. Environmental factors are heterogeneous and genetic predisposition, immune dysregulation, or dysbiosis do not lead to the development of IBD in isolation. RESULTS: Current challenges in the study of environmental factors and IBD are how to effectively translate promising results from experimental studies to humans in order to develop models that incorporate the complex interactions between the environment, genetics, immunology, and gut microbiota, and limited high quality interventional studies assessing the effect of modifying environmental factors on the natural history and patient outcomes in ***: This article critically reviews the current evidence on environmental risk factors for IBD and proposes directions for future research.

关键词： Environmental factors Inflammatory bowel disease Exposomes

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

独塔斜拉桥动力性能分析

独塔斜拉桥动力性能分析

作者：韩兵（muhammad Habib）华中科技大学

学位级别：硕士

斜拉桥作为一种跨越能力强的缆索体系桥梁，以其高效，经济，美观，施工速度快而在中等跨度到大跨桥梁的建设中有着非常广泛的运用。当前其跨越能力可以从200m到1200m以上。对于这类柔性体系桥梁，在进行减隔震设计时，精确进行动力行... 详细信息

斜拉桥作为一种跨越能力强的缆索体系桥梁，以其高效，经济，美观，施工速度快而在中等跨度到大跨桥梁的建设中有着非常广泛的运用。当前其跨越能力可以从200m到1200m以上。对于这类柔性体系桥梁，在进行减隔震设计时，精确进行动力行为分析是十分必要的。本文以河南兰考某高速公路上的一座单塔斜拉桥的隔震设计为工程背景，运用ANSYS软件对其动力性能进行研究，对该斜拉桥进行了静力非线性和动力（地震）响应分析，此外，对一些减震设计方法进行了简要概述。主要内容与成果如下： 1、采用基于有限元方法（FEM）的ANSYS对该桥进行建模，通过基于Lanczos法的模态分析得到了该斜拉桥的模态及固有频率。有限元法在斜拉桥的动力反应分析中广为采纳，为了简化模态、减少计算费用，本文在建模中以空间梁单元和杆单元等模拟桥梁而不是采用复杂的实体单元。此外，由于斜拉桥的复杂性，本文采用位移收敛准则来避免非线性计算中的收敛性问题;2、针对实例桥梁进行了模态与时程分析，结果显示，由于自由振动的耦合效应，该桥具有复杂的振动模态，相对于横桥向和纵桥向，该桥在垂直方向具有较大柔性;3、选取El-Centro波作为输入地震波对该桥进行了完全瞬态分析，分析中采用的El-Centro波时长10秒，时间步0.0001秒，根据分析结果，对边中梁中跨、桥塔及斜拉索在不同时间点的动力行为进行了分析。以上研究及结果有助于该类桥梁的减震设计。

关键词：动力行为独塔斜拉桥时程分析减震设计

LC-MS/MS Method for Determination of Colistin in Human Plasma: Validation and Stability Studies

在线全文

同方学位论文库

学校读者我要写书评

暂无评论

International Journal of Analytical Mass Spectrometry and Chromatography 2021年第1期9卷 1-11页

作者： Nada H. Binhashim Syed N. Alvi muhammad M. Hammami Clinical Studies and Empirical Ethics Department King Faisal Specialist Hospital & Research Center Riyadh KSA Alfaisal University College of Medicine Riyadh KSA

A simple and reliable high performance liquid chromatography tandem mass spectrometry (LC-MS/MS) assay for the determination of colistin A and colistin B in human plasma was developed and validated. Clarithromycin was used as an internal standard (IS). Plasma extraction was performed using C-18 cartridges and methanol containing 0.1% formic acid. Analysis was performed using Atlantis dC18 (2.1 × 100 mm, 3 μm) column at room temperature and a mobile phase of 0.2% formic acid in acetonitrile and water (50:50, v:v), delivered at a flow rate of 0.2 ml/minute. Eluent was detected in the positive ion mode using electrospray ionization at the following transitions of mass to charge (m/z): colistin A, 585.6 → 101.4;colistin B, 578.7 → 101.3;and IS, 748.6 → 158.4. No interference by components of blank plasma or commonly used drugs was observed. The relationship between colistin A colistin B concentrations and their corresponding peak height ratios to the IS was linear over the range of 0.05 - 10 μg/ml. Inter-day coefficient of variation and bias were, respectively, ≤11.5% and −3.0 to 6.0 for colistin A and ≤9.9 and −4.7 to 3.0 for colistin B. Mean extraction recovery of colistin A, colistin B, and the IS were 97%, 94%, and 97%, respectively. The method was applied to assess the stability of colistin A and colistin B in processed samples (24 hr. at room temperature, 48 hours at −20°C) and unprocessed samples (24 hr. at room temperature, 8 weeks at −20°C) and after three cycles of freeze and thaw found to be ≥87%.

关键词： Colistin Clarithromycin Human Plasma LC-MS/MS

Introduction, Sign, Symptoms, Prevention and Management of Lyme Disease Caused by Borrelia burgdorferi Channeled through Ixodes Ticks as Vector. A Review

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 Entomology 2016年第5期4卷 249-259页

作者： Fakhra Tabbasam muhammad Faheem Malik Usman Asghar Kamaran Saeed Paracha Takhmina Nazir University of Gujrat Ghakkhar Pakistan

God has created many miraculous creature;ticks are one of them. Borrelia burgdorferi is a bacterium that lives into the gut of ticks. When such ticks feed upon the blood of Ticks and other livestock, bacteria are transferred into their blood stream of these hosts. A disease is caused into human beings if such infected tick bites humans that are called as Lyme disease. This review will help to have a keen study on the cause, sign, symptoms, prevention and management of this disease.

关键词： Borrelia burgdorferi Livestocks

DNA Fingerprinting of Essential Commercialized Medicinal Plants from Pakistan

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9期8卷 2119-2132页

作者： Waqar Ahmad Khushi muhammad Altaf Hussain Habib Ahmad Khalid Kahn Iqbal Ahmed Qarshi Kamran Iqbal Shinwari muhammad Shahid Nadeem Youxiong Que Ayaz Khan Javed Iqbal Department of Genetics Hazara University Mansehra Pakistan Qarshi University Lahore and Qarshi Industries Hattar Pakistan School of Biological Sciences University of the Punjab Lahore Pakistan Key Lab of Sugarcane Biology and Genetic Breeding Ministry of Agriculture Fujian Agriculture and Forestry University Fuzhou China Department of Biochemistry Faculty of Science King Abdulaziz University Jeddah Saudi Arabia Women University Swabi Pakistan

Development of fingerprints based on DNA markers is necessary for proper identification and standardization of plant species. These techniques are widely used to develop an unquestionable method of plant identification to protect the patents and quality control for industry. In this study, fifteen commercially important medicinal plants of Pakistan were collected from botanical garden of Qarshi Industries (Pvt.) Ltd, Pakistan. The objective was to optimize the extraction of genomic DNA for use in a PCR-based random amplified polymorphic DNA marker approach. The initial protocol used 60 decamers to amplify scorable amplicons;only nine markers produced significant bands in genomic DNA of medicinal plants. These markers generated 51 bands ranging between 250 and 1600 bp. The most important property of genomic markers is polymorphism to enable specific identification;all the used markers showed 100% polymorphism across 15 different plants. Further, six decamers amplified specific bands to reliably identify 8 species. The amplified bands were arranged in a binary matrix and analyzed by DNAMAN version 5.2.2 statistical software. A homology tree was constructed using binary data for nine markers, and four major clusters/clades were observed. The Rose, Mentha and Stevia accessions had shown clear clustering and grouped in major clusters/clads I, II and III respectively. Sixty decamers amplified 51 polymorphic loci in the genomes of 15 commercially valuable accessions. Moreover clear phylogenetic construction was observed in the generation of homolog tree. This protocol could therefore be useful to provide a baseline to authenticate, identify and perform phylogenetic analysis of important medicinal plants used in the Pakistani herbal medicine industry.

关键词： RAPD Decamers Medicinal Plants DNA Fingerprinting

香蒲耐铬毒生理机理及其螯合剂诱导植物萃取污染土壤中重金属的研究

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

香蒲耐铬毒生理机理及其螯合剂诱导植物萃取污染土壤中重金属的研...

作者：大宇（muhammad Dawood）浙江大学

学位级别：硕士

土壤重金属污染正严重威胁着农产品的安全和人类健康。筛选鉴定抗/耐重金属的植物种/品种,探讨抗/耐性的生理生化机制,进而分离鉴定机关的特异基因.对于土壤重金属污染的植物修复具有重要的理论与实践指导意义。经野外调查,我们在浙江... 详细信息

土壤重金属污染正严重威胁着农产品的安全和人类健康。筛选鉴定抗/耐重金属的植物种/品种,探讨抗/耐性的生理生化机制,进而分离鉴定机关的特异基因.对于土壤重金属污染的植物修复具有重要的理论与实践指导意义。经野外调查,我们在浙江东南部地区三家开办了20余年的电镀厂周边受电镀废水、废弃物严重污染已无法种植农作物荒废多年的土壤上(土壤有效态Cr(VI)含量高达20mg/kg)发现了一种无铬中毒症状、生长旺盛、生物量大的多年生香蒲科香蒲属(Typhaceae)植物—狭叶香蒲(Typha angustifolia L.)。本研究采用盆栽试验,旨在探讨该狭叶香蒲对铬胁迫的耐性与相关的生理反应及其螯合剂诱导植物萃取污染土壤中重金属的可能性。主要研究结果如下: 盆栽试验研究了狭叶香蒲对铬毒害的耐性,并分析测定了相应的生理反应指标。与无铬对照相比,50μM Cr(VI)处理略提高了狭叶香蒲的株高和生物学产量,100μM Cr(VI)处理对株高和生物学产量并无显著影响;铬浓度增至200-800μM,植株的株高和生物学产量显著下降,但即便是在最高铬浓度800μM Cr(VI)胁迫下,植株叶片仍未见明显的铬中毒症状(叶片上未见坏死斑点)。因此,我们可以得出结论,该植物能在800μM Cr(VI)处理下正常生长,且无明显的铬毒害症状:说明这种香蒲科植物是一种对铬毒害具有很强耐性的植物。铬超积累植物是指植株铬含量超过1000mg kg1 DW,迁移系数达到0.02-0.10的植物种/品种。而香蒲植株的铬含量相对较低,因此该植物可能主要通过严格控制铬的‘土壤-植物’、‘根系-叶片’的迁移,从而限制了植株各部分铬含量。生理分析结果显示,铬胁迫显著提高了SOD和POD活性:叶片和根系中Cr和Mn含量呈显著正相关.Cr和另外3种微量元素(Fe、Zn、Cu)也呈正相关,但未达到显著水平。因此,根据本试验结果,香蒲对铬的耐性与铬胁迫下SOD和POD酶活性增强、必需微量元素吸收转移效率提高有关。外源添加金属螫合剂促进植物吸收积累重金属是利用高生物量植物种进行植物修复的可行手段之一。盆栽试验以狭叶香蒲为材料,研究了外源添加EDTACA(柠檬酸)刘,植物萃取污染土壤中Cd、Cu、Pb和Cr的作用。结果表明,香蒲对重金属毒害具有很强的抗性,各种重金属胁迫下香蒲植株地上部并未表现出中毒症状(欠绿或坏死)。与对照相比,施加EDTA显著降低了植株的株高、生物量,并严重影响植株正常生长发育:2.5 mM和5 mM CA处理显著提高了根系的(?)重。外源添加EDTA和CA均使地上部Cd、Pb和Cr含量显著上升,其中以EDTA效果更为明显。处理25 d收获时,5 mM EDTA处理地上部Cd、Cr和Pb含量最高,而2.5 mM CA处理根系Pb含景最高。10 mM CA处理地上部Cd累积量比2.5 mMEDTA处理高出了36.9%,与10 mM EDTA处理基本持平:但10 mM CA处理地上部Pb累积量较EDTA处理低。同时,CA处理下根系Cd、Cu和Pb累积量及5 mM或10 mM CA处理下地上部Cr累积量显著高于对照和EDTA处理。外源添加EDTA和CA对地上部Cu的累积量均无显著影响。实验结果也发现,外源加入EDTA显著增强了Cu、Cr、Pb和Cd在土壤中的溶解性;相比之下,CA对土壤水溶性Cu、Cr和Cd的影响较小,对Pb没有影响。综上所述,与EDTA相比,CA是一种环境友好的外源重金属螯合剂以诱导提高香蒲植物葶取污染土壤中的重金属。

关键词：柠檬酸(citric acid) 乙二胺四乙酸(ethylenediaminetetraacetic acid) 重金属丙二醛(MDA) 微量元素植物萃取过氧化物酶(POD) 超氧化物歧化酶(SOD) 耐性狭叶香蒲