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Design of a Fixed-Order Robust Controller to Damp Inter-Area Oscillations in Power Systems

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Journal of Power and Energy Engineering 2016年第3期4卷 61-70页

作者： Abdlmnam Abdlrahem Parimal Saraf karthikeyan Balasubramaniam Ramtain Hadidi Alireza Karimi Elham Makram Department of Electrical and Computer Engineering Clemson University Clemson USA Laboratoired'Automatique Ecole Polytechnique Fédérale de Lausanne (EPFL) Lausanne Switzerland

This paper presents the design of a robust fixed-order H∞ controller to damp out the inter-area oscillations and to enhance the stability of the power system. The proposed H∞ approach is based on shaping the open-loop transfer function in the Nyquist diagram through minimizing the quadratic error between the actual and the desired open loop transfer functions in the frequency domain under linear constraints that guarantee robustness and stability. The proposed approach is robust with respect to multi-model uncertainty closed-loop sensitivity functions in the Nyquist diagram through the constraints on their infinity norm. The H∞ constraints are linearized with the help of a desired open-loop transfer function. The controller is designed using the convex optimization techniques in which the difference between the open-loop transfer function and the desired one is minimized. The two-area four-machine test system is selected to evaluate the performance of the designed controller under different load conditions as well as different levels of wind penetrations.

关键词： H∞ Multi-Machine Power System Nyquist Diagram Robust Control Wind Penetrations SVC

家蚕末龄幼虫、蛹和成虫期载脂蛋白组成的变化(英文)

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昆虫学报 2017年第3期60卷 247-253页

作者： Thangaraj PRATHEEP Neelamegam RAMESHKUMAR Nagarajan KAYALVIZHI Thangaiyan SUGANYA Sivashanmugam karthikeyan Muthukalingan KRISHNAN Department of Environmental Biotechnology Bharathidasan University Tiruehirappalli-620024 India Department of Zoology Periyar University Salem-636011 India School of Bio Sciences & Technology VIT University Vellore-632014 India

【目的】载脂蛋白是一种重要的血淋巴脂蛋白,它将90%的脂类输送到内部器官。本研究旨在调查家蚕Bombyx mori各个发育期血淋巴载脂蛋白组成变化。【方法】采用溴化钾密度梯度超离心、肝素钠沉淀(heparin sodium precipitation)和连接蒸... 详细信息

【目的】载脂蛋白是一种重要的血淋巴脂蛋白,它将90%的脂类输送到内部器官。本研究旨在调查家蚕Bombyx mori各个发育期血淋巴载脂蛋白组成变化。【方法】采用溴化钾密度梯度超离心、肝素钠沉淀(heparin sodium precipitation)和连接蒸发光散射检测器的高效液相色谱(high performance liquid chromatography coupled with evaporative light scattering detector,HPLC-ELSD)等方法,检测了家蚕各个发育期血淋巴脂蛋白组成变化。【结果】从5龄幼虫到成虫的转变过程中,从幼虫期和吐丝期家蚕中分离的载脂蛋白密度分别为1.130和1.139 g/mL,但蛹期载脂蛋白密度降低(为1.083 g/mL)。应用肝素钠沉淀法对载脂蛋白组成的分析表明,家蚕吐丝期载脂蛋白主要是高密度载脂蛋白(9.8μg/μL);从吐丝期开始,低密度载脂蛋白含量增加,并在蛹期持续存在(4.2μg/μL)。在所有发育期,载脂蛋白Ⅲ含量低,在2日龄蛹中含量最高(4.0μg/μL)。另外,从吐丝期至成虫期,总脂浓度逐渐增加,从1.4μg/μL增加至3.8μg/μL。通过HPLC-ELSD对中性脂组成的分析表明,在所有发育期只含有微量的单酰甘油(<0.04μg/μL),在5龄幼虫中期至蛹期末观察到二酰甘油(0.11~0.61μg/μL),在蛹期发现三酰甘油(0.18~1.02μg/μL)。【结论】总体结果说明,在幼虫期和吐丝期,高密度载脂蛋白主要运输二酰甘油;化蛹后,高密度载脂蛋白更多地与三酰甘油有关,而与二酰甘油相关性小,并与载脂蛋白Ⅲ形成低密度载脂蛋白有关。这些结果提示载脂蛋白的转变是一个精确的时间控制过程。

关键词：家蚕载脂蛋白高密度载脂蛋白低密度载脂蛋白脂类

Tool Wear Classification Using Fuzzy Logic for Machining of Al/SiC Composite Material

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Modeling and Numerical Simulation of Material Science 2012年第2期2卷 28-36页

作者： V. Kalaichelvi R. karthikeyan D. Sivakumar V. Srinivasan Department of Electronics & Instrumentation Engineering BITS-Pilani Dubai Campus Dubai International Academic City Dubai United Arab Emirates Department of Electronics &Instrumentation Engineering Annamalai University Tamil Nadu India Department of Manufacturing Engineering Annamalai University India Department of Mechanical Engineering BITS-Pilani Dubai Campus Dubai International Academic City Dubai United Arab Emirates

Tool wear state classification has good potential to play a critical role in ensuring the dimensional accuracy of the work piece and prevention of damage to cutting tool in machining process. During machining process, tool wear is an important factor which contributes to the variation of spindle motor current, speed, feed and depth of cut. In the present work, online tool wear state detecting method with spindle motor current in turning operation for Al/SiC composite material is presented. By analyzing the effects of tool wear as well as the cutting parameters on the current signal, the models on the relationship between the current signals and the cutting parameters are established with partial design taken from experimental data and regression analysis. The fuzzy classification method is used to classify the tool wear states so as to facilitate defective tool replacement at the proper time.

关键词： Tool Wear Classification Current Signal Regression Analysis Fuzzy Classification

化学镀镍过程的动电位及循环伏安研究(英文)

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电镀与涂饰 2008年第10期27卷 17-20,23页

作者： karthikeyan S Latha Mathavan Engineering College Latha Mathavan Nagar Kidaripatti Madurai 625301 Tamilnadu India

化学镀镍是一个采用合适的还原剂(如次磷酸钠)使镍离子在某催化界面上可控地自催化还原的过程,所生成的膜层附着良好,应用广泛。以次磷酸盐作为还原剂时,化学镀镍的沉积速率通常低于20μm/h,故研究了在有少量硫脲或其衍生物作为加速剂... 详细信息

化学镀镍是一个采用合适的还原剂(如次磷酸钠)使镍离子在某催化界面上可控地自催化还原的过程,所生成的膜层附着良好,应用广泛。以次磷酸盐作为还原剂时,化学镀镍的沉积速率通常低于20μm/h,故研究了在有少量硫脲或其衍生物作为加速剂的条件下,次磷酸盐体系中镍的化学沉积过程。通过动电位阴、阳极极化和循环伏安研究,评价了镀覆过程中各种加速剂的性能。结果表明,所研究的硫化物都有明显的阳极去极化作用。各种加速剂性能的优劣顺序为:甲基硫脲>N,N′–乙烯硫脲>烯丙基硫脲>乙酰硫脲>对甲苯基硫脲>硫脲>二苯基硫脲。此外,氨基硫脲的性能优于巯基琥珀酸。

关键词：化学镀镍动电位极化循环伏安加速剂硫脲及其衍生物

Molecular basis of the anti-inflammatory potential of a diarylheptanoid in murine macrophage RAW 264.7 cells

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Advances in Biological Chemistry 2013年第6期3卷 541-548页

作者： Bharathi Raja Rajaganapathy karthikeyan Thirugnanam Muthusamy Velusamy Shanmuganathan Anand Singaravelu Lakshmi Baddireddi Subadhra Tissue Culture and Drug Discovery Lab Centre for Biotechnology Anna University Chennai India Tissue Culture and Drug Discovery Lab Centre for Biotechnology Anna University Chennai India 2National Institute of Nutrition (Indian Council of Medical Research) Hyderabad India National Institute of Nutrition (Indian Council of Medical Research) Hyderabad India

Natural products play a significant role in human health in relation to the prevention and treatment of inflammatory disorders. In this study, we examined the molecular basis of the anti-inflammatory potential of a diarylheptonoid (DAH) isolated from Alpinia officinarum hexane extract (AOHE) with special emphasis on their ability to modulate the nuclear factor-κB (NF-кB) signaling involved in the inflammatory response. Measurement of Nitrite by Griess reaction which revealed the effect of DAH in RAW 264.7 macrophages showed an inhibition in the nitric oxide production through the suppression of inducible nitric oxide synthase (iNOS) gene level expression. NF-кB reporter gene assay suggests inhibition of NF-кB transcriptional activity, thus inhibiting LPS-induced phosphorylation and degradation of IкBα and a downregulation of NF-кB protein expression confirms the immunomodulatory effect of DAH. Furthermore, downregulation in the gene level expression of NF-кB signaling markers such as IL-1β, TNF-α and COX-2 suggests the anti-inflammatory potential of DAH via inhibition of NF-кB activation.

关键词： Diarylheptanoid NF-кB Lipopolysaccharide TNF-α COX-2 iNOS Cytokines

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锌-三氧化二铬复合镀层的特性(英文)

电镀与涂饰 2011年第9期30卷 12-15页

作者： karthikeyan S VENKATACHALAM G NARAYANAN S SRINIVASAN K N Materials Division SASVIT UniversityVellore-632014India

采用由氧化锌 12 g/L、氢氧化钠 94 g/L、2-氨基-3-羧基吡啶 4.2 g/L、四乙烯五胺 17 g/L、三乙醇胺 2 g/L、专利表面活性剂0.5 g/L及碳三氧化二铬(粒径2 μm)0 ～ 11 g/L组成的镀液,于温度 50 °C、pH 6.5 和电流密度 4 A/dm2的条件下... 详细信息

采用由氧化锌 12 g/L、氢氧化钠 94 g/L、2-氨基-3-羧基吡啶 4.2 g/L、四乙烯五胺 17 g/L、三乙醇胺 2 g/L、专利表面活性剂0.5 g/L及碳三氧化二铬(粒径2 μm)0 ～ 11 g/L组成的镀液,于温度 50 °C、pH 6.5 和电流密度 4 A/dm2的条件下,在低碳钢上电镀 Zn-Cr2O3复合镀层。其显微硬度采用维氏硬度计测量,耐磨性用 Taber 磨耗试验机测量,表面形貌和显微组织采用扫描电镜(SEM)、X 射线衍射(XRD)及 X 射线光电子能谱(XPS)进行分析,在 3.5%(质量分数)NaCl 溶液中的耐蚀性以电化学阻抗谱(EIS)评价。证实了锌基体中存在团聚的 Cr2O3颗粒。与纯锌镀层相比,Zn-Cr2O3复合镀层的机械性能及耐蚀性能更好。

关键词：锌三氧化二铬复合镀层耐蚀性显微硬度耐磨性

Psychosocial Profile of HIV Patients on HAART in Southern India

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World Journal of AIDS 2011年第4期1卷 192-197页

作者： Jayakumar Palanisamy karthikeyan Murugesan Senthilkumar Subramanian Uma Devi Pitchai Chinnapidaran Rajamahendravarman Vellandi Inigo Beula 不详

BACKGROUND: Mortality of HIV/AIDS patients comes down in India after the National Aids Control Organization started providing free Antiretroviral Therapy (ART) since 2004. Madurai ART Center started providing free ART since 2004. Psychosocial profile of this population explored in this study. METHODS: A cross sectional interview conducted during the year 2008 with semi structured questionnaire on HIV positive clients who are on Highly Active Anti-Retro- viral Therapy (HAART) for more than 6 months. Convenience sampling done and totally 433 clients were interviewed with informed consent. RESULTS: Three fourth (73.4%) of the clients know about ART centre through Government Hospitals or Primary Health Centre. Most of the Clients (98.6%) on ART are feels back to normal life or back to near normal life. Pill burden/ Pill fatigue perceived by clients is 4.8%.Discrimination perceived was 8.8% and mostly in their own house or by neighbors, but most of their children (99.2%) were not discriminated as per the clients. Spouse positive rate for the married clients was 61.5% and unmarried in this population was 4.6%. Major or minor psychological problems in this group were 39.7% and attempted suicide was 8.8%. Drug abuse (alcohol and smoking) while started on ART was 40.4% and the current abusers are 7.6%. CONCLUSION: This study supports effectiveness of free ART program and effective case referral from government institutions. High percentage of major or minor psychological problem warrants further exploratory study and may need psychological interventions in this population.

关键词： HIV AIDS Antiretroviral Therapy Psychosocial

2,3-Diaryl-3H-imidazo[4,5-b]pyridine derivatives as potential anticancer and anti-inflammatory agents

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Acta Pharmaceutica Sinica B 2017年第1期7卷 73-79页

作者： Erin Marie Kirwen Tarun Batra Chandrabose karthikeyan Girdhar Singh Deora Vandana Rathore Chaitanya Mulakayala Naveen Mulakayala Amy Catherine Nusbaum Joel Chen Haneen Amawi Kyle Mc Intosh Sahabjada Neelam Shivnath Deepak Chowarsia Nisha Sharma Md Arshad Piyush Trivedi Amit KTiwari Department of Pharmacology and Experimental Therapeutics College of Pharmacy & Pharmaceutical SciencesUniversity of Toledo School of Pharmaceutical Sciences Rajiv Gandhi Technical University The University of Queensland School of Pharmacy Dr. Reddy’s Institute of Life Sciences University of Hyderabad Campus The University of Queensland School of Biomedical Sciences Department of Biosciences Sri Satya Sai Institute of Higher LearningAnantapur campus Clearsynth Labs Ltd. Research CentreIDA-Mallapur Molecular Endocrinology Lab Department of ZoologyUniversity of Lucknow University Institute of Pharmacy Chhatrapati Shahu Ji Maharaj University

In this study we examined the suitability of the 3H-imidazo[4,5-b]pyridine ring system in developing novel anticancer and anti-inflammatory agents incorporating a diaryl pharmacophore. Eight 2,3-diaryl-3H-imidazo[4,5-b]pyridine derivatives retrieved from our in-house database were evaluated for their cytotoxic activity against nine cancer cell lines. The results indicated that the compounds showed moderate cytotoxic activity against MCF-7, MDA-MB-468, K562 and SaOS2 cells, with K562 being the most sensitive among the four cancer cell lines. The eight 2,3-diaryl-3H-imidazo[4,5-b]pyridine derivatives were also evaluated for their COX-1 and COX-2 inhibitory activity in vitro. The results showed that compound 3f exhibited 2-fold selectivity with IC_(50) values of 9.2 and 21.8 mmol/L against COX-2 and COX-1, respectively. Molecular docking studies on the most active compound 3f revealed a binding mode similar to that of celecoxib in the active site of the COX-2 enzyme.

关键词： 3H-Imidazo[4,5-b]pyridine Cytotoxicity MTT assay COX inhibitors Docking studies

Review of imaging and endovascular intervention of iliocaval venous compression syndrome

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World Journal of Radiology 2020年第3期12卷 18-28页

作者： Ming Ren Toh Tjun Yip Tang Han Hui Mervin Nathan Lim Nanda Venkatanarasimha karthikeyan Damodharan Duke-NUS Medical School Singapore 544886Singapore Department of Vascular surgery Singapore General HospitalSingapore 169608Singapore Yong Yoo Ling School of Medicine Singapore 117597Singapore Department of Radiology Singapore General HospitalSingapore 169608Singapore Department of Radiology SengKang General HospitalSingapore 544886Singapore

Iliocaval venous compression syndrome(ICS)is the extrinsic compression of the common iliac vein by the overlying iliac artery against the *** compression can lead to venous stenosis and stasis,which manifests as chronic venous disease and treatment ***,early recognition of ICS and prompt treatment are *** presentations of ICS can be ambiguous and diagnosis requires a high index of suspicion with the relevant imaging *** initial imaging test is typically a Duplex ultrasound for vessel assessment and pelvic ultrasound to exclude a compressive mass,which is followed by computed tomography(CT)or magnetic resonance(MR)*** and MRI can identify the anatomical causes for venous *** patients with high clinical suspicion for ICS,negative findings on CT and MR venography would still warrant further *** diagnosis can be established using catheter-based venography complemented with intravascular ultrasonography but the nature of their invasiveness limits its utility as a routine imaging *** this review paper,we will discuss the evidence,utility and limitations of the existing imaging modalities and endovascular intervention used in the management of ICS.

关键词： Iliocaval venous compression syndrome Duplex ultrasound Intravascular ultrasound Computed tomography venography Magnetic resonance venography Endovascular stent