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Dielectric Properties of Ni-Zn Ferrites Synthesized by Citrate Gel Method

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World Journal of Condensed Matter Physics 2012年第2期2卷 57-60页

作者： K. Rama krishna Dachepalli Ravinder K. vijaya Kumar Utpal S. Joshi v. A. Rana Abrham Lincon Department of Chemsitrys P.G. College of Science Osmania University Hyderabad India Department of Physics Gujarat University Ahmedabad India Department of Physics Jawaharlal Nehru Technological University Hyderabad India Department of Physics Malla Reddy College of Engineering & Technology Secunderabad India Department of Physics P.G. College of Science Osmania University Hyderabad India

Ni-Zn ferrite with composition of Ni1-xZnxFe2O4 (x = 0.0, 0.2, 0.4, 0.6, 0.8, 0.9, 1.0) were prepared by citrate gel method. The Dielectric Properties for all the samples were investigated at room temperature as a function of frequency. The dielectric constant shows dispersion in the lower frequency region and remains almost constant at higher frequencies. The frequency dependence of dielectric loss tangent (tan δ) is found to be abnormal, giving a peak at certain frequency for mixed Ni-Zn ferrites. A qualitative explanation is given for the composition and frequency dependence of the dielectric loss tangent.

关键词： Ferrites Citrate Method Lattice Parameter Dielectric Constant Dielectric Loss

Extraction Kinetics of Ni(II) in the Ni2+- SO42--Ac-(Na+, H+)-Cyanex 272 (H2A2)-Kerosene-3% (v/v) Octan-1-ol System Using Single Drop Technique

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International Journal of Nonferrous Metallurgy 2013年第2期2卷 80-88页

作者： Ranjit Kumar Biswas Aneek krishna Karmakar Muhammad Saidur Rahman Department of Applied Chemistry and Chemical Engineering Rajshahi University Rajshahi Bangladesh

The kinetics of extraction of Ni(II) in the Ni2+-SO4 2_AC- (Na+, H+)-Cyanex 272 (H2A2)-kerosene-3% (v/v) octan-1-ol system using the single falling drop technique have been reported. The flux of Ni2+ transfer (F) at 303 K in presence of 3% (v/v) octan-1-ol (de-emulsifier) can be represented as:.Depending on reaction parameters, the activation energy (Ea) and enthalpy change in activation (DH±) varies within 17 - 58 kJ/mol and 17 - 67 kJ/mol, respectively. Entropy change in activation (DS±) is always negative. Based on the empirical flux equation, Ea and DS± values, mechanisms of extractions in different parametric conditions are proposed. At low and [Ac-], and pH, the chemical controlled step is: Ni2+ + A- → NiA+;and this reaction occurs via an SN2 mechanism. But in most parametric conditions, the process is under intermediate control;and at high SO42- and [Ac-], and pH, the extraction process is under diffusion control.

关键词： Kinetics Cyanex 272 Sulphate Kerosene Ni2+ Single Drop Technique

Color Image Segmentation Using Feedforward Neural Networks with FCM

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International Journal of Automation and computing 2016年第5期13卷 491-500页

作者： S.Arumugadevi v.Seenivasagam Department of Information Technology Sri Krishna Engineering College Department of Computer Science & Engineering National Engineering College (Autonomous)

This paper proposes a hybrid technique for color image segmentation. First an input image is converted to the image of CIE L＊a＊b＊ color space. The color features ＂a＂ and ＂b＂ of CIE L^＊a^＊b^＊ are then fed into fuzzy C-means （FCM） clustering which is an unsupervised method. The labels obtained from the clustering method FCM are used as a target of the supervised feed forward neural network. The network is trained by the Levenberg-Marquardt back-propagation algorithm, and evaluates its performance using mean square error and regression analysis. The main issues of clustering methods are determining the number of clusters and cluster validity measures. This paper presents a method namely co-occurrence matrix based algorithm for finding the number of clusters and silhouette index values that are used for cluster validation. The proposed method is tested on various color images obtained from the Berkeley database. The segmentation results from the proposed method are validated and the classification accuracy is evaluated by the parameters sensitivity, specificity, and accuracy.

关键词： Color image segmentation neural networks fuzzy C-means (FCM) soft computing clustering

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一种新定义——炸药的特性位

火炸药

火炸药 1986年第1期 50-55页

作者： v.krishna Mohan Tong B.Tang 郑孟菊

1.引言炸药的特性可用威力表示,可理解为单位时间的作功能力.另一个与此密切相关的术语是猛度,它是炸药装药对非常近邻物质的粉碎效应.民用炸药工业中通常用威力,军事领域内则较常使用猛度.至今还不能用基本的物理化学性质对这两个术语... 详细信息

1.引言炸药的特性可用威力表示,可理解为单位时间的作功能力.另一个与此密切相关的术语是猛度,它是炸药装药对非常近邻物质的粉碎效应.民用炸药工业中通常用威力,军事领域内则较常使用猛度.至今还不能用基本的物理化学性质对这两个术语给出清楚而定量的定义.本文的目的是在这方面作一尝试.一般是炸药的威力愈大,猛度就愈大,但含大量金属的炸药是例外.可能的原因是沿C-J等熵曲线独特的高压膨胀行为造成的,我们在这里不考虑这些炸药.对于CHNO型炸药威力在很大程度上取决于炸药爆轰时产生的气体体积和热量;而猛度主要受炸药装填密度和爆速的控制.

关键词：威力钢板金属板爆轰产物圆筒试验爆速猛度炸药密度

Development of Non-Labeled QCM Biosensor for the Detection of β-Galactosidase: A Comparative Study of Gold and Polystyrene Nanoparticles

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Advances in Nanoparticles 2013年第2期2卷 182-190页

作者： krishna Pal Singh Manav Kumar Choudhary Iva Chianella Prashant Singh Cranfield Biotechnology Centre Cranfield Health Cranfield University Bedfordshire England Department of Chemistry D.A.V. (PG) College Dehradun H.N.B. Garhwal University Srinagar India Membrane Biophysics & Nanobiosensor Research Laboratory C.B.S H G. B. Pant University of Agriculture& Technology Pantnagar India

The performance of gold and polystyrene nanoparticles was investigated using quartz crystal microbalance (QCM) as sensor platform;β-Galactosidase antibody with corresponding antigen was utilized for the immunoreaction. The development of the immunosensor included: 1) formation of self assembled monolayers on quartz crystals;2a) immobilization of p-aminothiophenol functionalized gold nanoparticles on carboxyl-terminated self assembled monolayer, or 2b) immobilization of polystyrene nanoparticles on crystals modified with p-aminothiophenol self assembled monolayer;3) attachment of monoclonal anti β-Gal on nanoparticles;and 4) detection of target analyte. The nanoparticles used were synthesized in house and characterized by transmission electron microscopy and infrared spectroscopy. The results revealed that antibodies were strongly attached to functionalized gold nanoparticles;the weaker immobilization of antibodies to polystyrene nanoparticles provoked their detachment during antigen detection. When cross reactivity of polystyrene nanoparticles was checked using a different antigen (Brucella), displacement of antibody was not recorded, demonstrating specificity of the reaction. To the best of our knowledge this is the first direct comparison between behaviors of biosensors developed with two commonly used nanoparticles. The results showed that both nanoparticles produced biosensors capable to detect β-Gal. Nevertheless biosensors developed using polystyrene nanoparticles are simpler, cheaper and more eco-friendly than those developed using gold nanoparticles.

关键词： QCM Biosensor β-Galactosidase Gold Nanoparticle Polystyrene Nanoparticle

Separation of Copper and Nickel by Solvent Extraction Using LIX 664N

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Journal of Environmental Protection 2013年第4期4卷 315-318页

作者： Rashmi Kumar Dahyalal J. Shah krishna Kant Tiwari D. J. Sanghvi College of Engineering Mumbai India Jaypee University of Engineering and Technology (JUET) Madhya Pradesh India Mukesh Patel School of Technology Management & Engineering (NMIMS) Mumbai India

Separation of copper and nickel by liquid-liquid extraction from aqueous solutions was studied using LIX 664N in kerosene as solvent. Both metals were taken in their sulfate form and ratio of copper to nickel in feed solutions was maintained as 10:1. LIX 664N concentration in kerosene was varied from 10% to 40% (v/v) and its effect was studied on percent extraction of copper and nickel for organic to aqueous (O:A) phase ratio of 2:1 at pH 2. Experimental results showed that at pH 2, copper was selectively extracted from its mixture with nickel. Selectivity for copper extraction was as high as 6000 with 40% LIX 664N. Calculations using extraction isotherm indicate almost complete recovery of copper in two stages with O:A ratio of 1:1 and in one stage with O:A ratio of 2:1. After extraction of copper, the pH of raffinate containing nickel was adjusted to a value of 9 by addition of ammonia solution. The effect of LIX 664N concentration on extraction of nickel was studied. Up to 80% nickel could be extracted with 30% LIX 664N at O:A phase ratio of 2:1. Stripping of copper from the organic phase with 180 g/l sulfuric acid at O:A phase ratio of 1:1 gave 98.5% copper recovery in a two-stage operation.

关键词： Copper Nickel LIX 664N Solvent Extraction Distribution Coefficient Selectivity

Mechanical behavior of organo-modified Indian bentonite nanoclay fiber-reinforced plastic nanocomposites

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Frontiers of Materials Science 2013年第4期7卷 396-404页

作者： N. RAGHAvENDRA H. N. NARASIMHA MURTHY M. krishna K. R. vISHNU MAHESH R. SRIDHAR S. FIRDOSH G. ANGADI S. C. SHARMA Center for Manufacturing and Research Technology Utilization R. V. College Campus Bangalore 560059 Karnataka India Department of Mechanical Engineering R. V. College of Engineering Bangalore 560059 Karnataka India Department of Chemistry ACS College of Engineering Bangalore 560074 Karnataka India Tumkur University Tumkur 572103 Karnataka India

The aim of the research was to examine the influence of organo-modified Indian bentonite （IB） nanoclay dispersed in vinyisster on the mechanical properties of nanoclaylvinylesterlglass nanocomposRes. Nanoclay was organically modified using cationic surfactant hexadecyltrimethylammonium bromide （HDTMA-Br） by cation exchange method and dispersed in vinylester using ultrasonication and twin screw extrusion. XRD of nanoclaylvinylester revealed exfoliaUon at 4 wt.% nanoclay indicating uniform dispersion in the polymer. DSC results showed improvement in glass transition temperature by 22.3% in 4 wt.% nanoclaylvinylester/glass when compared with that of vinylester/glass. Nanoclay/vinylester/glass with 4 wt,% nanoclay showed 29.23%, 23.84% and 60.87% improvement in ultimate tensile strength （UTS）, fiexural strength （FS） and interlaminar shear strength （ILSS） respectively when compared with those of vinylester! glass. The mode of tensile failure examined by SEM showed no agglomeration of nanoclay in 4 wt.% nanoclayNinylester/glass specimens.

关键词： Indian bentonite (IB) ultrasonication twin-screw extrusion mechanical property

Childhood Glaucoma: An Overview

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Open Journal of Ophthalmology 2012年第3期2卷 71-77页

作者： Parul Singh Yogesh Kumar Manoj Tyagi krishna Kuldeep Parmeshwari Das Sharma Department of Ophthalmology V.C.S.G.G.M.S. & R.I. Srinagar Garhwal Uttarakhand India

Several types of childhood glaucoma exist, and the terminology is based on the time of onset of disease and its potential cause. Though childhood glaucoma occurs less commonly than adults but can lead to permanent visual damage due to amblyopia, optic neuropathy or refractive error. A detailed evaluation should be done to establish diagnosis. Medical therapy has a limited role and surgery remains main modality for treatment. Childhood glaucoma is a treatable disease, if early diagnosis is established and therapeutic intervention done in time. In children with low vision efforts should be there to maintain residual vision and visual rehabilitation with low vision aids should be done.

关键词： Childhood Glaucoma Goniotomy Trabeculotomy

Artery of Percheron occlusion:role of diffusion-weighted imaging in the early diagnosis

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Neuroimmunology and Neuroinflammation 2016年第1期3卷 14-16页

作者： Murali krishna Menon Suma Mariam Jacob Muhammed Jasim Abdul Jalal Department of Neurology Lakeshore Hospital and Research CentreErnakulam 682040KeralaIndia Department of Radiology Lakeshore Hospital and Research CentreErnakulam 682040KeralaIndia Department of Family Medicine Lakeshore Hospital and Research CentreErnakulam 682040KeralaIndia

Bilateral thalamic infarcts have a low frequency among different subtypes of *** it does not involve a particular vascular territory,it therefore usually involves the occlusion of the artery of Percheron(AOP).Here we report a 79-year-old right-handed Parkinsonian female patient,who was found unresponsive in *** examination,the patient was drowsy with a Glasgow Coma Score(GCS)of 10/15(E2M5v3).She had absent doll’s eye response with anisocoric pupils and intermittent vertical gaze *** the patient had no apparent motor deficits,she was in a state of persistent somnolence with memory impairment and lack of ***-weighted magnetic resonance imaging(MRI)of the brain showed focal areas of restricted diffusion in the medial part of the thalami bilaterally and the rostral part of mid-brain(right>left)(bilateral paramedian thalamic with mid-brain pattern),suggestive of a hyper-acute infarct in the territory of *** patient was anticoagulated with 40 mg subcutaneous low molecular weight heparin and was started on double anti-platelets along with supportive *** level of consciousness is improved at a slow rate to a GCS of 12/15(E4M5v3).The patient had marked abulia with periods of drowsiness interspersed with periods of restlessness and uttering of abnormal sounds,but she was able to execute simple *** conclusion,occlusion of the AOP is a rare cause of coma in elderly ***-weighted MRI is the imaging modality of choice for early *** diagnosis of AOP occlusion may lead to favorable outcomes.

关键词： Artery of Percheron bilateral thalamic infarcts coma diffusion-weighted imaging thalamic dementia