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Acta metallurgica Sinica(English Letters) 2015年第3期28卷 394-404页

作者： m.jay chithra m.Sathya K.Pushpanathan PG & Research Department of Physics Government Arts College

The effects of pH value on crystal size and optical property of zinc oxide nanoparticles prepared by chemical precipitation method were *** samples have been characterized by means of X-ray diffraction,scanning electron microscopy,ultraviolet-visible spectrometer and photoluminescence *** X-ray diffraction profile,it is found that the particle size of sample increases from 13.8 to 33 nm when the pH value of the solution was increased from 6 to *** study also shows that the particle size increases with pH *** shape of the zinc oxide nanoparticle has been confirmed by the scanning electron microscopy *** recorded ultraviolet-visible spectrum shows excitonic absorption peaks around 381 *** energy gap of the prepared samples has been determined from the ultraviolet-visible absorption spectrum,effective mass model equation and Tauc＇s *** was found that the energy gap of the prepared samples decreases with increase in pH *** recorded blue shift confirmed the quantum confinement effect in the prepared zinc oxide *** spectrum infers that the increase in pH value shifts the ultraviolet-visible emission but not the violet and green emissions.

关键词： Zinc oxide nanoparticles pH value Crystal structure microstructure Energy gap Photoluminescence

Uncovering the dominant contribution of intermediate volatility compounds in secondary organic aerosol formation from biomass-burning emissions

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National Science Review 2024年第3期11卷 150-158页

作者： Kun Li Jun Zhang David m.Bell Tiantian Wang Houssni Lamkaddam Tianqu Cui Lu Qi mihnea Surdu Dongyu Wang Lin Du Imad El Haddad jay G.Slowik Andre S.H.Prevot Environment Research Institute Shandong University Laboratory of Atmospheric Chemistry Paul Scherrer Institute

Organic vapors from biomass burning are a major source of secondary organic aerosols(SOAs). Previous smog chamber studies found that the SOA contributors in biomass-burning emissions are mainly volatile organic compounds(VOCs). While intermediate volatility organic compounds(IVOCs) are efficient SOA precursors and contribute a considerable fraction of biomass-burning emissions, their contribution to SOA formation has not been directly observed. Here, by deploying a newly-developed oxidation flow reactor to study SOA formation from wood burning, we find that IVOCs can contribute ～70% of the formed SOA, i.e.>2 times more than VOCs. This previously missing SOA fraction is interpreted to be due to the high wall losses of semi-volatile oxidation products of IVOCs in smog chambers. The finding in this study reveals that SOA production from biomass burning is much higher than previously thought, and highlights the urgent need for more research on the IVOCs from biomass burning and potentially other emission sources.

关键词： atmospheric chemistry biomass burning secondary organic aerosol intermediate volatility organic compounds

Lithium ion conduction and ion-polymer interaction in poly(vinyl pyrrolidone) based electrolytes blended with different plasticizers

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Chinese Chemical Letters 2014年第11期25卷 1428-1434页

作者： K.Kesavan chithra m.mathew S.Rajendran School of Physics Alagappa University

Poly（ethylene oxide）, poly（vinyl pyrrolidone）（PEO/PVP）, lithium perchlorate salt（Li Cl O4） and different plasticizer based, gel polymer electrolytes were prepared by the solvent casting technique. XRD results show that the crystallinity decreases with the addition of different plasticizers. Consequently, there is an enhancement in the amorphousity of the samples responsible for the process of ion transport. FTIR spectroscopy is used to characterize the structure of the polymer and confirms the complexation of plasticizer with host polymer matrix. The ionic conductivity has been calculated using the bulk impedance obtained through impedance spectroscopy. Among the various plasticizers, the ethylene carbonate（EC） based complex exhibits a maximum ionic conductivity value of the order of2.7279 10 4S cm 1. Thermal stability of the prepared electrolyte films shows that they can be used in batteries at elevated temperatures. PEO（72%）/PVP（8%）/Li Cl O4（8%）/EC（12%） has the maximum ionic conductivity value which is supported by the lowest optical band gap and lowest intensity in photoluminescence spectroscopy near 400–450 nm. Two and three dimensional topographic images of the sample having a maximum ionic conductivity show the presence of micropores.

关键词： Polymers Thermogravimetric analysis(TGA) X-ray diffraction Luminescence Transport properties

An Improved Pairing-Free Ciphertext Policy Framework for IoT

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Computer Systems Science & Engineering 2023年第6期45卷 3079-3095页

作者： m.Amirthavalli S.chithra R.Yugha Department of Information Technology Sri Sivasubramaniya Nadar College of EngineeringRajiv Gandhi Salai(OMR)Kalavakkam603110Tamil NaduIndia

Internet of Things(IoT)enables devices to get connected to the *** they are connected,they behave as smart devices thereby releasing sensitive data *** is a necessity to preserve the confidentiality and integrity of this data during transmission in public communication channels and also permitting only legitimate users to access their data A key challenge of smart networks is to establish a secure end-to-end data communication architecture by addressing the security vulnerabilities of data users and smart *** objective of this research work is to create a framework encompassing Ciphertext policy Attribute-based Encryption scheme using block encryption and BLAKE hashing *** improved Pairing-Free-Ciphertext policy Attribute-based encryption algorithm has been developed to overcome the aforementioned ***,a comparative study has been performed between the proposed scheme and the different encryption *** is found that the proposed scheme scores well over the already existing *** scheme is evaluated in terms of execution time and communication *** robustness of the proposed scheme is also analyzed from the perspective of several security goals.

关键词： Internet of things access control cipher policy based-attribute based encryption(CP-ABE) access matrix performance analysis

Scientific observations at total solar eclipses

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Research in Astronomy and Astrophysics 2009年第6期9卷 613-634页

作者： jay m. Pasachoff Williams College-Hopkins Observatory Williamstown Massachusetts 01267 USA California Institute of Technology 150-21 Pasadena CA 91125

The occasion of the longest totality of an eclipse in the 18 yr 11^1/3 d saros cycle leads to taking stock of the scientific value of ground-based eclipse observations in this space age. Though a number of space satellites from the U.S., Europe, Japan, and Russia study the Sun, scientists at eclipses can observe the solar chromosphere and corona at higher spatial resolution, at higher temporal resolution, and at higher spectral resolution than are possible aloft. Furthermore, eclipse expeditions can transport a wide variety of state-of-the-art equipment to the path of totality. Thus, for at least some years to come, solar eclipse observations will remain both scientifically valuable and cost-effective ways to study the outer solar atmosphere.

关键词： Sun eclipses

Thermally insulating robust carbon composite foams with high EmI shielding from natural cotton

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Journal of materials Science & Technology 2021年第35期94卷 113-122页

作者： A.chithra Praveen Wilson Sujith Vijayan R.Rajeev K.Prabhakaran Department of Chemistry Indian Institute of Space Science and TechnologyThiruvananthapuram 695547India Analytical and Spectroscopy Division Vikram Sarabhai Space CentreThiruvananthapuram 695022India

Thermally insulating and fire-resistant carbon composite foams are prepared by consolidating natural cotton fibre dispersed in aqueous sucrose solution by filter-pressing followed by drying and *** compressive strength(5 kPa to 1.4 mPa)and thermal conductivity(0.069 to 0.185 W m^(-1)K^(-1))depend on the foam density(0.06 to 0.31 g cm^(-3))which is modulated by varying the sucrose solutions concentration(100 to 700 g L^(-1)).Partially flexible to the rigid transition of the carbon composite foams occurs at sucrose concentration above 200 g L^(-1).The tubular carbon fibre formed from cotton is welded at their contact points by the amorphous carbon produced from sucrose leading to partial flexibility at low sucrose concentration and advancement of fibre-to-fibre bonding area at higher sucrose concentration results in rigid *** porosity in the inter-fibre space and lumen of the carbonized cotton fibre contributes to the low thermal *** carbon composite foams prepared at a sucrose solution concentration of 500 g L^(-1) and above are amenable to machining using conventional machines and *** rigid carbon foams show EmI shielding effectiveness and specific shielding effectiveness in the ranges of 21.5 to 38.9 d B and 108-138 dB cm^(3) g^(-1),respectively.

关键词： Foams natural fibres thermal properties consolidation mechanical properties emi shielding properties

Pain management strategies in penile implantation

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Asian Journal of Andrology 2020年第1期22卷 34-38页

作者： Jeffrey L Ellis Andrew m Higgins jay Simhan Department of Urology Einstein Healthcare NetworkDivision of Urologic OncologyDepartment of Surgical OncologyFox Chase Cancer CenterPhiladelphiaPA 19141 USA

The opioid epidemic continues to be a serious public health *** have pointed to prescription drug misuse as a nidus for patients to become addicted to opioids and as such,urologists and other surgical subspecialists must critically define optimal pain management for the various procedures performed within their respective *** pain following penile prosthesis implantation remains a unique challenge for urologists,given the increased pain patients commonly experience in the postoperative *** most of the existing urological literature focuses on interventions performed in the operating room,there are many studies that examine the role of preoperative adjunctive pain medicine in diminishing postoperative narcotic *** are relatively few studies looking at postoperative strategies for managing pain in prosthetic surgery with follow-up past the immediate *** review assess the various strategies employed for managing pain following penile implantation through the lens of the current state of the opioid crisis,thus examining how urologists can responsibly treat pain without contributing to the growing threat of opioid addiction.

关键词： analgesia epidemic opioid pain prosthetic

An update on the diagnosis of gastroenteropancreatic neuroendocrine neoplasms

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World Journal of Gastroenterology 2022年第10期28卷 1009-1023页

作者： Jiayun m Fang jay Li Jiaqi Shi Department of Pathology&Clinical Labs University of MichiganAnn ArborMI 48109United States medical Scientist Training Program University of MichiganAnn ArborMI 48109United States

Gastroenteropancreatic neuroendocrine neoplasms(GEP-NENs)arise from neuroendocrine cells found throughout the gastrointestinal tract and islet cells of the *** incidence and prevalence of GEP-NENs have been increasing each year due to higher awareness,improved diagnostic modalities,and increased incidental detection on cross-sectional imaging and endoscopy for cancer screening and other conditions and ***-NENs are a heterogeneous group of tumors and have a wide range in clinical presentation,histopathologic features,and molecular *** presentation most commonly depends on whether the GEP-NEN secretes an active *** World Health Organization recently updated the classification of GEP-NENs to introduce a distinction between high-grade neuroendocrine tumors and neuroendocrine carcinomas,which can be identified using histology and molecular studies and are more aggressive with a worse prognosis compared to high-grade neuroendocrine *** our understanding of the biology of GEP-NENs has grown,new and improved diagnostic modalities can be developed and ***,we discuss clinical features and updates in diagnosis,including histopathological analysis,biomarkers,molecular techniques,and radiology of *** review established diagnostic tests and discuss promising novel diagnostic tests that are currently in development or require further investigation and validation prior to broad utilization in patient care.

关键词： Neuroendocrine tumor Neuroendocrine carcinoma Gastrointestinal Pancreas Pathology Diagnosis

modeling corrosion behavior of gas tungsten arc welded titanium alloy

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中国有色金属学会会刊：英文版 2007年第4期17卷 676-680页

作者： m. Balasubramanian V. jay abalan V. Balasubramanian Department of mechanical Engineering Maamallan Institute of Technology Anna University Department of manufacturing Engineering Anna University Department of manufacturing Engineering Annamalai University

The pitting corrosion characteristics of pulse TIG welded Ti-6Al-4V titanium alloy in marine environment were explained. Besides the rapid advance of titanium metallurgy, this is also due to the successful solution of problems associated with the development of titanium alloy welding. The preferred welding process of titanium alloy is frequently gas tungsten arc(GTA) welding due to its comparatively easier applicability and better economy. In the case of single pass GTA welding of thinner section of this alloy, the pulsed current has been found beneficial due to its advantages over the conventional continuous current process. The benefit of the process is utilized to obtain better quality titanium weldments. Four factors, five levels, central composite, rotatable design matrix are used to optimize the required number of experiments. The mathematical models have been developed by response surface method(RSm). The results reveal that the titanium alloy can form a protective scale in marine environment and is resistant to pitting corrosion. Experimental results are provided to illustrate the proposed approach.

关键词：钛合金脉冲电流钨电极惰性气体保护焊腐蚀行为

Does variable stand structure associated with multi-cohort forests support diversity of ground beetle (Coleoptera, Carabidae) communities in the central Nearctic boreal forest？

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Journal of Forestry Research 2016年第5期27卷 1191-1202页

作者： Erica P. Barkley jay R. malcolm Sandy m. Smith m. Isabel Bellocq Faculty of Forestry University of Toronto 33 Willcocks Street Toronto ON M5S 3B3 Canada Departamento de Ecología Genética y Evolución IEGEBA(CONICET-UBA) Facultad de Ciencias Exactas y NaturalesUniversidad de Buenos Aires Buenos Aires Argentina

multi-cohort management （mCm） that retains a range of stand structures （age and size class） has been proposed to emulate natural disturbance and improve management in the Nearctic boreal forest. Although mCm forests contain both single- and multi-aged stands of mixed tree sizes, little is known about how variable stand structure affects associated fauna and biodiversity. Here, we examine the relationship between ground beetle （Coleoptera, Carabidae） communities and stand characteristics across a range of forest structure （=cohort classes）. Given that mCm classes are defined by the distribution of their tree-stem diameters, we ask whether parameters associated with these distributions （Weibull） could explain observed variation in carabid communities, and if so, how this compares to traditional habitat variables such as stand age, foliage complexity or volume of downed woody debris. We sampled carabids using weekly pitfall collections and compared these with structural habitat variables across a range of cohort classes （stand structure and age since disturbance） in 18 sites of upland mixed boreal forests from central Canada. Results showed that richness and diversity of carabid communities were similar among cohort classes. Weibull parameters from the diameter distribution of all stems were the strongest predictors of variation in carabid communities among sites, but vertical foliage complexity, understory thickness, and percentage of deciduous composition were also significant. The abundance of several carabid forest specialists was strongly correlated with tree canopy height, the presence of large trees, and high vertical foliage complexity. Our results demonstrate that variable forest structure, as expected under mCm, may be useful in retaining the natural range of ground beetle species across the central Nearctic boreal forest.

关键词： Biodiversity conservation Boreal forest Carabidae Forest structure Ground beetles multi-cohortmanagement Tree diameter distribution