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An ecofriendly approach for corrosion control of 6061 Al-15%(v)SiC(P)composite and its base alloy

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Chinese Journal of Chemical Engineering 2017年第3期25卷 363-372页

作者： Charitha B.P. Padmalatha rao Department of chemistry Manipal Institute of TechnologyManipalUdupiKamatakaIndia

Corrosion inhibition characteristics of bio polymer dextran was studied for the corrosion control of 6061 Al-15%_((v)) SiC_((P)) composite and its base alloy in 1 mol·L^(-1) HCl. Standard electrochemical techniques such as potentiodynamic polarization(PDP) measurements and electrochemical impedance spectroscopy(EIS) method were adopted for corrosion rate measurement. Surface morphology was studied by scanning electron microscopy(SEM) and elemental mapping was done by energy dispersive X-ray(EDX) analysis. Suitable mechanism was proposed for corrosion and inhibition process. Results indicated that dextran acts as an excellent anticorrosive agent for the corrosion control of 6061 Al-15%_((v)) SiC_((P)) composite, with maximum inhibition efficiency of 91% for the concentration of 0.4 g·L^(-1) at 303 k. Dextran acted as a mixed type of inhibitor, and got physically adsorbed both on composite and base alloy by obeying Langmuir adsorption isotherm. Dextran is proved to be a green inhibitor with environmental and economic benefits.

关键词： 6061 Al-15%(v) SiC(p) composite Green inhibitor Biopolymer Electrochemical studies SEM–EDX

Geochemical assessment of a siliceous limestone sample for cement making

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Chinese Journal Of Geochemistry 2011年第1期30卷 33-39页

作者： rao D.S. vijayakumar T.v. Prabhakar S. Bhaskar Raju G. National Metallurgical Laboratory-Madras Centre CSIR Madras Complex Taramani Chennai-600 113 India

A low grade siliceous limestone sample from the Jayantipuram mine of Andhra Pradesh, India, has been investigated for its suitability for cement making. Petrological as well as X-ray diffraction pattern studies indicated that the limestone sample was crystalline and dominantly composed of calcite and quartz. They are simple in mineralogy, and yet they have variable silica and lime contents. Geochemical analysis results of twenty five hand picked samples indicated that the limestone from the Jayantipuram mine shows a wide range of variations in LOI (29.94% to 40.64%), SiO2 (6.14% to 27.18%), CaO (37.93% to 50.78%), Al2O3 (0.49% to 2.27%) and Fe2O3 (0.28% to 2.4%). MgO, k2O, Na2O, TiO2 and MnO2 are present in traces. CaO with LOI shows a strong positive correlation where as CaO with SiO2 shows a strong negative correlation because of mineralogical factors. The chemical composition of the limestone reflects its mineralogical composition. The distribution of various elements in the acid-soluble fraction has been studied by the factor analysis method in order to interpret in terms of their mineralogy, sedimentary environment and diagenesis. Mineralogy, recrystallization and other diagenetic changes are the main factors affecting the distribution of the elements and their mutual relationships in the limestone. The aim of this paper is also to analyze how significantly the two parameters, silica modulus and lime saturation factor, influence this low grade siliceous limestone sample from the Jayantipuram mine of Andhra Pradesh, India, for the cement making process from the geochemical data.

关键词：灰岩样品水泥生产地球化学硅质石灰石矿评估因子分析方法化学数据处理

Amberlyst-15 catalyzed synthesis of alkyl/aryl/heterocyclic phosphonates

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Chinese Chemical Letters 2011年第8期22卷 895-898页

作者： U.M.rao kunda v.N.Reddy Mudumala C.S.Reddy Gangireddy B.R.Nemallapudi k.N.Sandip S.R.Cirandur Department of Chemistry Sri Venkateswara UniversityTirupati 517502.India Bio-Organic Division BARCMumbaiIndia

A novel and efficient procedure for the synthesis of alkyl phosphonates through one pot condensation of alkyl halide and trialkyl /aryl phosphite in the presence of Amberlyst-15 as catalyst under solvent free conditions was *** demonstrated several advantages such as good yields of products,simple operation,convenient separation and inexpensive catalyst.

关键词： Dialkyl/aryl alkyl phosphonates Amberlyst-15

Effect of hydrogen plasma treatment on the growth and microstructures of multiwalled carbon nanotubes

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Nano-Micro Letters 2010年第1期2卷 42-48页

作者： S.k.Srivastava v.D.vankar v.kumar Department of Physics Indian Institute of Technology Delhi National Physical Laboratory Dr.K.S.Krishnan Marg

The effect of hydrogen plasma treatment of iron oxide films on the growth and microstructure of carbon nanotubes(CNTs)by microwave plasma enhanced chemical vapor deposition process has been *** plasma was characterized in-situ using optical emission *** of the films was examined by scanning electron *** analysis was carried out by high resolution transmission electron microscopy(HRTEM)equipped with energy dispersive X-ray spectroscopy(EDS)and micro-diffraction *** is found that oxide films without H_2 plasma pretreatment or treated for lesser time resulted in CNT films with high percentage of carbonaceous particles and with embedded particles/nanorods distributed discontinuously in the cavity of the *** embedded particles were found to be of iron carbide(Fe-C)as confirmed by HRTEM,EDS and micro-diffraction *** observations suggested that the iron oxide particles had poor catalytic action for CNT growth and in-situ reduction of oxide clusters to Fe by hydrogen plasma plays a key role in discontinuous filling of the nanotubes by the catalytic particles.

关键词： Carbon nanotubes Chemical vapor deposition Iron carbide MPECvD

Effect of welding processes on mechanical and microstructural characteristics of high strength low alloy naval grade steel joints

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Defence Technology（防务技术） 2015年第3期11卷 308-317页

作者： S.RAGU NATHAN v.BALASUBRAMANIAN S.MALARvIZHI A.G.rao Department of Manufacturing Engineering Annamalai University Centre for Materials Joining & Research (CEMAJOR) Department of Manufacturing EngineeringAnnamalai University Naval Materials Research Laboratory (NMRL)

Naval grade high strength low alloy(HSLA) steels can be easily welded by all types of fusion welding processes. However, fusion welding of these steels leads to the problems such as cold cracking, residual stress, distortion and fatigue damage. These problems can be eliminated by solid state welding process such as friction stir welding(FSW). In this investigation, a comparative evaluation of mechanical(tensile, impact,hardness) properties and microstructural features of shielded metal arc(SMA), gas metal arc(GMA) and friction stir welded(FSW) naval grade HSLA steel joints was carried out. It was found that the use of FSW process eliminated the problems related to fusion welding processes and also resulted in the superior mechanical properties compared to GMA and SMA welded joints.

关键词：低合金高强度钢焊接工艺钢接头组织结构力学性能搅拌摩擦焊机械特性焊接方法

Investigation of tuberculosis clusters in Dehradun city of India

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Asian Pacific Journal of Tropical Medicine 2010年第6期3卷 486-490页

作者： Neeraj Tiwari vineeta kandpal Ajoy Tewari k.Ram Mohan rao Tolia vS Department of Statistics Kumaun UniversitySSJ CampusAlmora-263601India Department of Anatomy ERA's Medical CollegeLucknow-226001India Jai Clinic & Diabetes Care Centre Lucknow-226001India Geoinformatics Division Indian Institute of Remote SensingDehradun-248001India District Tuberculosis Officer Dehradun 248001India

Objective:To investigate the presence of statistically significant geographical clusters of tuberculosis(TB) using Geographical Information System and spatial scan statistics in Dehradun, ***:The spatial scan statistic implemented with a software program,SaTScan v6.1, was used to test the presence of statistically significant spatial clusters of TB and to identify their approximate locations(Pven wards of the Dehradun Municipal area. Conclusions:There is sufficient evidence about the existence of statistically significant TB clusters in seven wards of Dehradun,*** purely spatial scan statistics methodology used in this study has a potential use in surveillance of TB for detecting the true clusters of the disease.

关键词： Geographical Information System Mycobacterium tuberculosis Spatial scan statistics TB/HIv

Skeletal contraction:A novel strategy to access multisubstituted cyclobutane

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Green Synthesis and Catalysis 2022年第1期3卷 1-3页

作者： Chunfa Xu v.U.Bhaskara rao Fen-Er Chen Institute of Pharmaceutical Science and Technology College of ChemistryFuzhou UniversityFuzhou 350108China Department of Chemical Biology Max Planck Institute for Molecular PhysiologyDortmund 44227Germany Engineering Center of Catalysis and Synthesis for Chiral Molecules Department of ChemistryFudan UniversityShanghai 200433China Shanghai Engineering Center of Industrial Asymmetric Catalysis for Chiral Drugs Fudan UniversityShanghai 200433China

The polysubstituted and spirocyclic cyclobutanes were efficiently constructed by the utilization of a novel skeletal contraction strategy which only took one-step synthesis from the readily accessible *** mechanistic studies indicated that a key intermediate N-aminated pyrrolidine was formed initially and subsequent extrusion of a nitrogen via a radical pathway completed the *** practical methodology was further highlighted by the concise,formal synthesis of the cytotoxic natural product piperarborenine B.

关键词： Cyclobutane Skeletal contraction Hypervalent iodine Pyrrolidines Piperarboreine B

Photometric study of W UMa type binaries in the intermediate open cluster NGC 7789

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Research in Astronomy and Astrophysics 2010年第2期10卷 159-165页

作者： kandulapati Sriram Pasagada vivekananda rao Department of Astronomy Osmania University

The light curve solutions of two W UMa binary systems in the intermediate open cluster NGC 7789 are presented in this paper. These variables were observed using the 2 m telescope of the IUCAA-Girawali Observatory. The v passband photo- metric solutions of the two W UMa binaries were obtained using the latest version of the W-D program. The result shows that both systems are H-subtype W UMa binaries with high mass ratios.

关键词： binaries: eclipsing- binaries: close

Natural history of Barrett's esophagus

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World Journal of Gastroenterology 2012年第27期18卷 3483-3491页

作者： rao Milind Stephen E Attwood Department of Surgery North Tyneside General HospitalNorth ShieldsTyne and Wear NE29 8NHUnited Kingdom

The natural history of Barrett's esophagus (BE) is difficult to quantify because,by definition,it should describe the course of the condition if left ***,we assume that patients with BE will receive symptomatic treatment with acid suppression,usually a proton pump inhibitor,to treat their *** paper describes the development of complications of stricture,ulcer,dysplasia and adenocarcinoma from this *** over the definition of BE and its implications in clinical practice are *** presence of intestinal metaplasia and its relevance to cancer risk is discussed,and the need to measure the extent of the Barrett's epithelium (long and short segments) using the Prague guidelines is *** and international consensus over the diagnosis and management of BE are being regularly *** need for expert consensus is important due to the lack of randomized trials in this *** searching the literature,we have tried to collate the important studies regarding progression of Barrett's to dysplasia and *** therapeutic studies yet reported show a clear reduction in the development of cancer in *** effect of pharmacological and surgical intervention on the natural history of Barrett's is a subject of ongoing research,including the Barrett's Oesophagus Surveillance Study and the aspirin and esomeprazole cancer chemoprevention trial with interesting *** geographical variation and the wide range of outcomes highlight the difficulty of providing an individualized risk profile to patients with *** studies on the interaction of genome wide abnormalities in Barrett's and their interaction with environmental factors may allow individualization of the risk of cancer developing in BE.

关键词： Barrett's esophagus Columnar lined esoph-agus Dysplasia Adenocarcinoma Gastroesophagealreflux Surgery