检索结果-南通市图书馆

Study of central Intensity Ratio of Seyfert Galaxies in Nearby Universe

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2023年第4期23卷 85-93页

作者： K.T.Vinod c.Baheeja S.Aswathy c.d.ravikumar department of Physics University of CalicutMalappuram-673635India department of Physics Providence Women's CollegeCalicut-673009India

We use the recently discovered simple photometric parameter central Intensity Ratio(cIR)determined for a sample of 57 nearby(z<0.02)Seyfert galaxies to explore the central features of galaxies and their possible conne... 详细信息

We use the recently discovered simple photometric parameter central Intensity Ratio(cIR)determined for a sample of 57 nearby(zcentral features of galaxies and their possible connection with galaxy *** sample of galaxies shows strong anti-correlation between cIR and mass of their central supermassive black holes(SMBHs).The SMBH masses of ellipticals are systematically higher for a given cIR value than those for lenticulars and spirals in the ***,the correlation between cIR and central velocity dispersion is *** appears less influenced by the excess flux produced by the central engine in these galaxies,when compared to spectroscopic parameters like velocity dispersion and OⅣflux,and proves to be a fast and reliable tool for estimating central SMBH mass.

关键词： Galaxy evolution-galaxies active-galaxies photometry-(galaxies:)quasars supermassive black holes-galaxies Seyfert

Long term optical variability of bright X-ray point sources in elliptical galaxies

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2014年第10期14卷 1251-1263页

作者： V.Jithesh Ranjeev Misra P.Shalima K.Jeena c.d.ravikumar B.R.S.Babu department of Physics University of CalicutMalappuram-673635India Inter-University centre for Astronomy and Astrophysics Post Bag 4GaneshkhindPune-411007India department of Physics Providence Women's CollegeMalaparambaCalicut-673009India department of Physics Sultan Qaboos UniversityMuscatOman

We present long term optical variability studies of bright X-ray sources in four nearby elliptical galaxies with the chandra Advanced ccd Imaging Spectrometer array （AcIS-S） and observations from the Hubble Space Telescope （HST） Advanced camera for Surveys. Out of the 46 bright （X-ray counts 〉 60） sources that are in the common field of view of the chandra and HST observations, 34 of them have potential optical counterparts, while the rest of them are optically dark. After taking into account systematic errors, estimated using optical sources in the field as a reference, we find that four of the X-ray sources （three in NGc 1399 and one in NGc 1427） have variable optical counterparts at a high level of significance. The X-ray luminosities of these sources are ～10^38 erg S^-1 and are also variable on similar time scales. The optical variability implies that the optical emission is asso- ciated with the X-ray source itself rather than being the integrated light from a host globular cluster. For one source, the change in optical magnitude is 〉 0.3, which is one of the highest reported for this class of X-ray sources and this suggests that the optical variability is induced by the X-ray activity. However, the optically variable sources in NGc 1399 have been reported to have blue colors （g - z 〉 1）. All four sources have been detected in the infrared （IR） by Spitzer as point sources, and their ratios of 5.8 to 3.6 μm flux are 〉 0.63, indicating that their IR spectra are like those of Active Galactic Nuclei （AGNs）. While spectroscopic confirmation is required, it is likely that all four sources are background AGNs. We find none of the X-ray sources having opticalfiR colors different from AGNs to be optically variable.

关键词： (Galaxy ) globular clusters general -- galaxies photometry -- X-rays galaxies

Performance and Emission characteristics of a cRdI diesel Engine Fuelled by SiO_(2) Nanoparticle-Waste Fat Biodiesel Blends

在线全文

学校读者我要写书评

暂无评论

china Petroleum Processing & Petrochemical Technology 2024年第1期26卷 56-66页

作者： Babu Aurtherson P dinesh Babu Munuswamy ravikumar Jayabal Yuvarajan devarajan department of Mechanical Engineering Mahat Amma Institute of Engineering and TechnologyPudukkottaiTamil NaduIndia department of Mechanical Engineering Rajalakshmi Institute of TechnologyChennaiTamil NaduIndia department of Thermal Engineering Saveetha School of EngineeringSaveetha Institute of Medical and Technical SciencesChennaiTamil NaduIndia

This study investigates the use of waste fat biodiesel(WFB)from the leather industry as a substitute for diesel ***,it examines the diesel engine performance of WFB,a blend of WFB and diesel(B50),and different blends of WFB and silicon dioxide(SiO_(2))nanoparticles(B50SiO_(2)40,B50SiO_(2)80,and B50SiO_(2)120μg/g).The results indicate that the B50SiO_(2)120 blend increases brake thermal efficiency by 10.03%compared to pure biodiesel but falls 1.93%short of neat ***,the B50SiO_(2)120 mixture reduces smoke,hydrocarbon,and carbon monoxide emissions by 31.87%,34.14%,and 43.97%respectively,compared to ***,the B50SiO_(2)120 blend shows a 4.91%increase in nitrogen oxide emissions compared to diesel.

关键词： waste fat transesterification biodiesel silicon dioxide emission

Near resonance vibration isolation on a levered-dual response(LEdAR)coulomb-damped system by differential preloads/offsets in linear springs

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2024年第6期45卷 1033-1050页

作者： T.I.TOLUWALOJU c.K.THEIN d.HALIM department of Mechanical Materials and Manufacturing EngineeringUniversity of Nottingham Ningbo ChinaNingbo 315100Zhejiang ProvinceChina Nottingham Ningbo china Beacons of Excellence Research and Innovation Institute University of Nottingham Ningbo ChinaNingbo 315048Zhejiang ProvinceChina

The levered-dual response(LEdAR)coulomb-damped system attains near resonant vibration isolation by differential preloads/offsets in linear *** takes the advantages of both the preloads/offsets in linear springs and the guiderail friction for realizing different levels of vibration *** isolation capacities are investigated on the strategies with both the horizontal and vertical guiderails,with the horizontal rail only,and without *** compressive preloads generally result in the consumption of most of the initial excitation energy so as to overcome the potential *** isolation onsets at the frequency ratio of 1∓0.095 on the left-hand side(LHS)and the right-hand side(RHS)of the lever are relative to the load plate *** observed near resonant isolation thus makes the LEdAR system a candidate for the isolation of the mechanical systems about resonance while opening a path for simultaneous harvesterisolation functions and passive functions at extreme frequencies.

关键词： lever ratio coulomb damping preload tension/compression isolation band/depth offset potential

Prescribed-Time Nash Equilibrium Seeking for Pursuit-Evasion Game

在线全文

学校读者我要写书评

暂无评论

IEEE/cAA Journal of Automatica Sinica 2024年第6期11卷 1518-1520页

作者： Lei Xue Jianfeng Ye Yongbao Wu Jian Liu d.c.Wunsch Key Laboratory of Measurement and control of complex Systems of Engineering Ministry of EducationNanjing 210096 School of Automation Southeast UniversityNanjing 210096China department of Electrical and computer Engineering Missouri University of Science and TechnologyRollaMO 65409 USA IEEE

dear Editor,This letter is concerned with prescribed-time Nash equilibrium(PTNE)seeking problem in a pursuit-evasion game(PEG)involving agents with second-order *** order to achieve the prior-given and user-defined convergence time for the PEG,a PTNE seeking algorithm has been developed to facilitate collaboration among multiple pursuers for capturing the evader without the need for any global ***,it is theoretically proved that the prescribedtime convergence of the designed algorithm for achieving Nash equilibrium of ***,the effectiveness of the PTNE method was validated by numerical simulation results.A PEG consists of two groups of agents:evaders and *** pursuers aim to capture the evaders through cooperative efforts,while the evaders strive to evade *** is a classic noncooperative *** has attracted plenty of attention due to its wide application scenarios,such as smart grids[1],formation control[2],[3],and spacecraft rendezvous[4].It is noteworthy that most previous research on seeking the Nash equilibrium of the game,where no agent has an incentive to change its actions,has focused on asymptotic and exponential convergence[5]-[7].

关键词： seeking prescribed convergence

How can Practitioners Support citizen Volunteers in disaster Risk Reduction? Insight from “Good and Ready” in Aotearoa New Zealand

在线全文

学校读者我要写书评

暂无评论

International Journal of disaster Risk Science 2024年第3期15卷 374-387页

作者： Lo?c Le dé Steve Ronoh Ei Mon Thinn Kyu Brigitte Rive School of Public Health and Interdisciplinary Studies Auckland University of Technology Pacific Health Research centre Auckland University of Technology New Zealand Red cross

Global and national policy frameworks emphasize the importance of people's participation and volunteers' role in disaster risk reduction. While research has extensively focused on volunteers in disaster response and recovery, less attention has been paid on how organizations involved in disaster risk management can support volunteers in leading and coordinating communitybased disaster risk reduction. In 2019, the New Zealand Red cross piloted the Good and Ready initiative in Auckland,Aotearoa New Zealand, with the objective to empower local people in resilience building with a focus on volunteers and community participation. This research examined the positive and negative outcomes of Good and Ready and investigated volunteers' experiences in the disaster resilience initiative. It involved the codesign of a questionnaire-based survey using participatory methods with Good and Ready volunteers, the dissemination of the survey to gather volunteers' viewpoints, and a focus group discussion with participatory activities with Red cross volunteers. The findings highlight that a key challenge lies in finding a balance between a program that provides flexibility to address contextual issues and fosters communities' ownership, versus a prescriptive and standardized approach that leaves little room for creativity and self-initiative. It pinpoints that supporting volunteers with technical training is critical but that soft skills training such as coordinating, communicating,or facilitating activities at the local level are needed. It concludes that the sustainability of Good and Ready requires understanding and meeting volunteers' motivations and expectations and that enhancing partnerships with local emergency management agencies would strengthen the program.

关键词： community-based approach disaster risk reduction New Zealand Participation Volunteers

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

基于非天然氨基酸的蛋白质合成研究进展

食品与发酵工业 2024年第12期50卷 336-342页

作者：赵梅刘馨远陈洋商洁丛宏日马豪 ravikumar Yuvaraj 齐向辉江苏大学食品与生物工程学院江苏镇江212013

蛋白质是生命体的重要组成部分,几乎参与了所有的生命活动。通常情况下生物体中蛋白质由20种天然氨基酸组成,但随着现代科技的飞速发展,人们对医疗、食品、材料等方面的需求日渐增大,这些蛋白质已经无法满足多样化的应用需求。随着非天... 详细信息

蛋白质是生命体的重要组成部分,几乎参与了所有的生命活动。通常情况下生物体中蛋白质由20种天然氨基酸组成,但随着现代科技的飞速发展,人们对医疗、食品、材料等方面的需求日渐增大,这些蛋白质已经无法满足多样化的应用需求。随着非天然氨基酸及其合成的蛋白质的优异性能,使得利用非天然氨基酸改造蛋白质的技术逐渐成为研究热点。非天然氨基酸有着不同于天然氨基酸的侧链基团,可以给蛋白质带来新的性质与功能。该文基于对非天然氨基酸及非天然蛋白质的研究,首先介绍了以化学及生物的手段合成非天然氨基酸的方法,同时对化学及生物法的优劣势及未来的发展前景进行了总结;然后介绍了将非天然氨基酸掺入蛋白质的几种热门方法;接着对非天然氨基酸及其合成蛋白质的应用在酶的改造、科研以及医疗方面进行了列举和描述;最后对这项技术未来的发展进行了展望与总结。

关键词：非天然氨基酸非天然蛋白质细胞代谢工程遗传密码扩展酶的改造蛋白药物改造

Polio eradication surveillance in Sri Lanka,2019-2023

在线全文

学校读者我要写书评

暂无评论

Asian Pacific Journal of Tropical Medicine 2024年第6期17卷 268-272页

作者： M.A.Y.Fernando N.S.Madarasinghe c.Rangana N.Weerasinghe d.c.U.d.Weligamage J.I.Abeynayake department of Medical Microbiology and Immunology Faculty of MedicineUniversity of ColomboSri Lanka department of Virology Medical Research InstituteColombo 08Sri Lanka Medical Research Institute Colombo 08Sri Lanka

Objective:To evaluate the polio laboratory surveillance carried out from January,2019 to May,2023 by the Polio Regional Reference Laboratory,Sri ***:This retrospective study analyzed all stool samples received under the acute flaccid paralysis(AFP)and immunodeficient vaccine-derived poliovirus(VdPV)surveillance at Polio Regional Reference Laboratory,Sri Lanka from January,2019 to May,*** results of the testing methodologies were extracted from the laboratory data system,i.e.,poliovirus virus isolation,intra-typic differentiation/VdPV real time reverse transcriptase polymerase chain reaction(ITd/VdPV rRTPcR)and sequencing,along with the data on timing of reporting results,stool adequacy and *** was analyzed using descriptive ***:A total of 2141 stool samples from 1644 cases were received for AFP surveillance from Sri Lanka(93.61%),Maldives(1.52%),and immunodeficient VdPV(4.86%)*** polioviruses(19/1644,1.15%)and non-polio enteroviruses(73/1644,4.44%)were isolated,while Sabin-like 3 virus was detected in majority(12/19,63.15%)among the poliovirus *** polioviruses or circulating VdPVs were not detected among the *** all years of the study,the non-polio AFP detection rate was>1/100000 in children aged less than 15 years,whereas stool adequacy rate was>80%.All results were reported within 14 days of receipt,ensuring timely reporting as per global ***:The Polio Regional Reference Laboratory,Sri Lanka plays a vital role in maintaining the polio-free status in the country through its robust laboratory surveillance,while adhering to the surveillance ***-detection of wild polioviruses and circulating VdPV during the study period reinforces the polio-free status in the country.

关键词： Poliovirus Polio laboratory surveillance Regional reference laboratory Polio eradication

Solar-driven cO_(2) conversion to methane and methanol using different nanostructured cu_(2)O-based catalysts modified with Au nanoparticles

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Energy chemistry 2024年第4期91卷 287-298页

作者： João Angelo Lima Perini Lilian d.Moura Torquato Juliana Fde Brito Gustavo A.Andolpho Mateus A.Gonçalves Leonardo d.de Angelis Lucas d.Germano Susana I.córdoba de Torresi Teodorico c.Ramalho Maria V.Boldrin Zanoni São Paulo State University(UNESP) Institute of ChemistryRua Prof.Francisco Degni55AraraquaraSP 14800-060Brazil National Institute of Alternative Technologies for detection Toxicological Evaluation and Removal of Micropollutants and Radioactive Substances(INCT-DATREM)São Paulo State University(UNESP)Institute of ChemistryRua Prof.Francisco Degni55AraraquaraSP 14800-060Brazil Laboratory of Molecular Modelling Department of ChemistryNatural Sciences InstituteFederal University of LavrasLavrasMG 37200-900Brazil department of chemistry Faculty of ScienceUniversity of Hradec KrálovéHradec Králové50003Czech Republic Instituto de Química Universidade de São PauloAv.Prof.Lineu Prestes 74805508-080São PauloSPBrazil

This work describes the use of TiO_(2)nanotubes-based electrodes(TNT)modified with cu_(2)O nanostructures and gold nanoparticles for the photoelectroreduction of cO_(2)to produce value-added compounds.A thin layer of polydopamine was used as both an adherent agent and an electron transfer mediator,due to itsπ-conjugated electron *** highest production yield was achieved using a TNT@PdA/Nc/Au40%electrode,with Faradaic efficiencies of 47.4%(110.5μM cm^(-2))and 27.8%(50.4μM cm^(-2))for methanol and methane,*** performance of the photoelectrodes was shown to be cu_(2)O facet-dependent,with cubic structures leading to greater conversion of cO_(2)to methanol(43%)and methane(27%),compared to the octahedral morphology,while a higher percentage of metallic gold on the nanostructured cu_(2)O surface was mainly important for *** functional theory(dFT)calculations supported these findings,attributing the superior photoelectrocatalytic performance of the TNT@PdA/Nc/Au40%electrode for cH4generation to the formation of an OcH3intermediate bonded to Au *** using isotope-labeling and analysis by gas chromatograph-mass(Gc-MS)demonstrated that13cO_(2)was the source for photoelectrocatalytic generation of13cH3OH and13cH313cH2OH.

关键词： cu_(2)O nanocubes Photoelectrocatalysis Polydopamine cO_(2) photoelectroreduction dFT calculations