检索结果-南通市图书馆

Cool white light and tunable multicolor emission from Tb^(3+)/Dy^(3+)co-activated glasses under different excitations for WLEDs

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2024年第1期42卷 46-56,I0002页

作者： L.Vijayalakshmi k.Naveen kumar Jong Dae Baek Department of Automotive Engineering Yeungnam UniversityGyeongsanGyeongbuk38541Republic of Korea Department of Mechanical Engineering Yeungnam UniversityGyeongsan38541Republic of Korea

A set of co-doped(Tb^(3+)/Dy^(3+))lithium zinc borate(LZB)glasses were developed by melt *** structural evaluation was performed for synthesized glassy *** Dy^(3+)and Tb^(3+)individually doped glasses exhibit intense yellow and green luminescence bands at 575 nm(^(4)F_(9/2)→^(6)H_(13/2))and543 nm(^(5)D_(4)→^(7)F_(5)),*** sensitization effect of Dy^(3+)on Tb^(3+)was analyzed by increasing the Tb^(3+)content with respect to the optimum Dy^(3+)content(0.5 mol%)in Dy^(3+)/Tb^(3+).The spectral overlay of Dy^(3+)luminescence and Tb^(3+)absorption profiles,Dy^(3+)/Tb^(3+)PL spectra under different excitations 352,362,376,and 385 nm,shortening decay lifetimes of Dy^(3+)in Dy^(3+)/Tb^(3+)co-activated glasses,energy transfer(ET)parameters,chromaticity coordinates and their corresponding correlated temperatures all help to explain ET from Dy^(3+)to Tb^(3+).At 385 nm of Dy^(3+)excitation,the optimized co-activated(0.5Dy^(3+)+1.0Tb^(3+)):LZB glass displays cool white light *** non-radiative ET from Dy^(3+)to Tb^(3+)is dominated by electric dipole-dipole interaction and its ET efficiency was calculated to be 63%.At the same time,reverse ET from Tb^(3+)to Dy^(3+)was also *** shift in color coordinates from dominant yellow to greenish-yellow,green and white light emission suggests that Dy^(3+)/Tb^(3+)coactivated LZB glasses can be a potential candidate for UV converted multicolor and white light emitting devices.

关键词： Rare earths Photoluminescence Energy transfer Spectral overlap Decay lifetime Multicolor emitting LEDs

SARS-CoV-2 and innate immunity:the good,the bad,and the"goldilocks"

在线全文

学校读者我要写书评

暂无评论

Cellular & Molecular Immunology 2024年第2期21卷 171-183页

作者： Benjamin L.Sievers Mark T.k.Cheng kata Csiba Bo Meng Ravindra k.Gupta Department of Medicine University of CambridgeCambridgeUK Cambridge Institute of Therapeutic Immunology&Infectious Disease(CITID) Department of MedicineUniversity of CambridgeCambridgeUk

An ancient conflict between hosts and pathogens has driven the innate and adaptive arms of *** about this interplay can not only help us identify biological mechanisms but also reveal pathogen vulnerabilities that can be leveraged *** humoral response to SARS-CoV-2 infection has been the focus of intense research,and the role of the innate immune system has received significantly less ***,we review current knowledge of the innate immune response to SARS-CoV-2 infection and the various means SARS-CoV-2 employs to evade innate defense *** also consider the role of innate immunity in SARS-CoV-2 vaccines and in the phenomenon of long COVID.

关键词： SARS-CoV-2 Innate immune response Interferon Cytokines Inflammation Antiviral targets

Compression properties of cost-efficient porous expanded clay reinforced AA7075 syntactic foams fabricated by industrial-oriented die casting technology

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

China Foundry 2024年第1期21卷 60-70页

作者： İsmail Cem Akgün Çağın Bolat Ali Gökşenli Faculty of Mechanical Engineering Istanbul Technical University34437İstanbulTurkey Faculty of Engineering Samsun University55420SamsunTurkey

In today’s manufacturing industries,hard competition between rival firms makes it compulsory for researchers to design lighter and cheaper machine components due to the megatrends of cost-effectiveness and *** this point,aluminum syntactic foams(ASFs)are new-generation engineering composites and come into the upfront as a *** to their features like low density,sufficient elongation,and perfect energy absorption ability,these advanced foams have been considerably seductive for many industrial sectors *** this study,an industrial-oriented automatic die casting technology was used for the first time to manufacture the combination of AA7075/porous expanded clay(PEC).Micro evaluations(optical and FESEM)reveal that there is a homogenous particle distribution in the foam samples,and inspections are compatible with the other ASF ***,T6 aging heat treatment was operated on one half of the produced foams to explore the probable impact of aging on the compressive *** results show that PEC particles can be an alternative to expensive hollow spheres used in the previous ***,a favorable relationship is ascertained between the aging treatment and mechanical properties such as compression strength and plateau strength.

关键词： die casting porous materials metal matrix sytanctic foams expanded clay compressive deformation

Emission colour tuning in kLnF_(4):Yb^(3+),Er^(3+)/Ho^(3+)phosphor

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2024年第1期42卷 57-65,I0002页

作者： Janani k Gayathri E Vijayatha V Ramasubramanian S Thiyagarajan P Department of Science and Humanities Nehru Institute of TechnologyKaliapuramThirumalayampalayamCoimbatoreIndia Department of Sciences Amrita School of Physical SciencesAmrita Vishwa VidyapeethamCoimbatoreIndia Department of Physics Anna UniversityChennaiIndia

kLnF_(4):Yb^(3+),Er^(3+)/Ho^(3+)(Ln=Y,Yb,Gd)phosphors were prepared by solid-state reaction *** each of the Yb^(3+)/Er^(3+)and Yb^(3+)/Ho^(3+)co-doped phosphors independently,phase confirmation and morphological examination were accomplished using the X-ray diffraction technique and scanning electron microscope analysis.X-ray photoelectron spectroscopy analysis shows the charge state and existence of lanthanides and *** luminescence emissions of green and red colour were detected for the synthesized *** changes in the upconverted emission intensities and colour output pertaining to the change of the lanthanide host matrix along with dopants were investigated for the prepared *** the upconversion luminescence,erbium-doped samples exhibit a predominance of red emission while holmium-doped samples display a prevalence of green *** rare-earth Er/Ho doped kYbF4shows strong red emission compared to other ***_(4):Yb,Er/Ho exhibits relatively significant green upconve rsion emissions,while Yb,Er-doped kGdF_(4)host displays a 10-fold increase in green/red emission ratio with an increase in the input power of 20-780 *** photoluminescence studies and decay curve analysis were carried out using UV light excitation for the developed phosphors.A higher lifetime of 2.2 ms was measured for the downshifting red emission in the Ho doped kYbF_(4)*** study suggests a potential for colour tunability in the upconversion and downshifting emissions through host modifications to the fluoride phosphor.

关键词： Rare earths Energy transfer upconversion Downshifting Colour coordinates

Optimised hybrid classification approach for rice leaf disease prediction with proposed texture features

在线全文

学校读者我要写书评

暂无评论

Journal of Control and Decision 2024年第1期11卷 84-97页

作者： Sakhamuri Sridevi k.kiran kumar Department of Computer Science and Engineering Koneru Lakshmaiah Education FoundationVaddeswaramIndia

This paper aims to frame a new rice disease prediction model that included three major ***,median filtering(MF)is deployed during pre-processing and then‘proposed Fuzzy Means Clustering(FCM)based segmentation’is *** that,‘Discrete Wavelet Transform(DWT),Scale-Invariant Feature Transform(SIFT)and low-level features(colour and shape),Proposed local Binary Pattern(LBP)based features’are extracted that are classified via‘MultiLayer Perceptron(MLP)and Long Short Term Memory(LSTM)’and predicted outcomes are *** exact prediction,this work intends to optimise the weights of LSTM using Inertia Weighted Salp Swarm Optimisation(IW-SSO)***,the development of IW-SSO method is established on varied metrics.

关键词： Rice disease improved fuzzy hybrid classifiers optimised LSTM IW-SSO algorithm

Sequential decay analysis of^(235)U(n^(th),f)reaction using fragmentation approach

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics C 2024年第6期48卷 145-154页

作者： Nitin Sharma Ashutosh kaushik Manoj k.Sharma School of Physics and Materials Science Thapar Institute of Engineering&TechnologyPatiala-147004PunjabIndia

Numerous experimental and theoretical observations have concluded that the probability of the three fragment emission(ternary fission)or binary fission increases when one proceeds towards the heavy mass region of nuclear periodic *** factors affect fragment emission,such as the shell effect,deformation,orientation,and fissility *** and ternary fissions are observed for both ground and excited states of the *** collinear cluster tripartition(CCT)channel of the^(235)U(n^(th),f)reaction is studied,and we observe that the CCT may be a sequential or simultaneous emission *** date,different approaches have been introduced to study the CCT process as a simultaneous or sequential process,but the decay dynamics of these modes have not been not fully *** the three fragments of the sequential process and exploring their related dynamics using an excitation energy dependent approach would be of further ***,in this study,we investigate the sequential decay mechanism of the^(235)U(n^(th),f)reaction using quantum mechanical fragmentation theory(QMFT).The decay mechanism is considered in two steps,where initially,the nucleus splits into an asymmetric *** the second step,the heavy fragment obtained in the first step divides into two *** I analysis is conducted by calculating the fragmentation potential and preformation probability for the spherical and deformed choices of the decaying *** most probable fragment combination of stage I are identified with respect to the dips in the fragmentation structure and the corresponding maxima of the preformation probability(P0).The light fragments of the identified decay channels(obtained in step I)agree closely with the experimentally observed *** excitation energy of the decay channel is calculated using an iteration *** excitation energy is shared using an excitation energy dependent level density *** obtained excitation

关键词： fission cluster radioactivity ternary fission spontaneous fission cluster model total kinetic energy preformation probability

Covalent Bond Based Android Malware Detection Using Permission and System Call Pairs

在线全文

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2024年第3期78卷 4283-4301页

作者： Rahul Gupta kapil Sharma R.k.Garg Department of Information Technology Delhi Technological UniversityNew Delhi110042India Department of Mechanical Engineering Deenbandhu Chhotu Ram University of Science and TechnologyMurthal131039India

The prevalence of smartphones is deeply embedded in modern society,impacting various aspects of our *** versatility and functionalities have fundamentally changed how we communicate,work,seek entertainment,and access *** the many smartphones available,those operating on the Android platform dominate,being the most widely used *** widespread adoption of the Android OS has significantly contributed to increased malware attacks targeting the Android ecosystem in recent ***,there is an urgent need to develop new methods for detecting Android *** literature contains numerous works related to Android malware *** far as our understanding extends,we are the first ones to identify dangerous combinations of permissions and system calls to uncover malicious behavior in Android *** introduce a novel methodology that pairs permissions and system calls to distinguish between benign and malicious *** approach combines the advantages of static and dynamic analysis,offering a more comprehensive understanding of an application’s *** establish covalent bonds between permissions and system calls to assess their combined *** introduce a novel technique to determine these pairs’Covalent Bond Strength *** pair is assigned two scores,one for malicious behavior and another for benign *** scores serve as the basis for classifying applications as benign or *** correlating permissions with system calls,the study enables a detailed examination of how an app utilizes its requested permissions,aiding in differentiating legitimate and potentially harmful *** comprehensive analysis provides a robust framework for Android malware detection,marking a significant contribution to the *** results of our experiments demonstrate a remarkable overall accuracy of 97.5%,surpassing various state-of-the-art detection techniques proposed in the current literature.

关键词： Android malware android security hybrid analysis permission and system call pairs

Improving Channel Estimation in a NOMA Modulation Environment Based on Ensemble Learning

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2024年第8期140卷 1315-1337页

作者： Lassaad k.Smirani Leila Jamel Latifah Almuqren Elearning Deanship and Distance Education Umm Al-Qura UniversityP.O.Box 715MekkahSaudi Arabia Department of Information Systems College of Computer and Information SciencesPrincess Nourah bint Abdulrahman UniversityP.O.Box 84428Riyadh11671Saudi Arabia

This study presents a layered generalization ensemble model for next generation radio mobiles,focusing on supervised channel estimation *** estimation typically involves the insertion of pilot symbols with a well-balanced rhythm and suitable *** model,called Stacked Generalization for Channel Estimation(SGCE),aims to enhance channel estimation performance by eliminating pilot insertion and improving *** SGCE model incorporates six machine learning methods:random forest(RF),gradient boosting machine(GB),light gradient boosting machine(LGBM),support vector regression(SVR),extremely randomized tree(ERT),and extreme gradient boosting(XGB).By generating meta-data from five models(RF,GB,LGBM,SVR,and ERT),we ensure accurate channel coefficient predictions using the XGB *** validate themodeling performance,we employ the leave-one-out cross-validation(LOOCV)approach,where each observation serves as the validation set while the remaining observations act as the training *** performances’results demonstrate higher mean andmedian accuracy compared to the *** achieves an average accuracy of 98.4%,precision of 98.1%,and the highest F1-score of 98.5%,accurately predicting channel ***,our proposedmethod outperforms prior traditional and intelligent techniques in terms of throughput and bit error ***’s superior performance highlights its efficacy in optimizing channel *** can effectively predict channel coefficients and contribute to enhancing the overall efficiency of radio mobile *** extensive experimentation and evaluation,we demonstrate that SGCE improved performance in channel estimation,surpassing previous ***,SGCE’s capabilities have significant implications for optimizing channel estimation in modern communication systems.

关键词： Stacked generalization ensemble learning Non-Orthogonal Multiple Access(NOMA) channel estimation 5G

New evidence for the epigenetic regulation of skeletal stem cells

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science Bulletin 2024年第13期69卷 2004-2006页

作者： Liming Zhao Jun Xiao Charles k.F.Chan Institute for Stem Cell Biology and Regenerative Medicine Stanford University School of MedicineStanford CA 94305USA Department of Surgery Division of Plastic and Reconstructive SurgeryStanford University School of MedicineStanford CA 94305USA Department of Orthopaedic Surgery Tongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430030China

Skeletal stem cells(SSCs)are crucial for skeletal development and regeneration,yet the epigenetic regulation of these cells remains poorly *** studies have delineated the epigenetic landscape across the developmental trajectory of SSCs,highlighting the involvement of Ptip in regulating SSC *** skeletal system undergoes dynamic remodeling throughout *** stem cells(SSCs),residing within the skeleton and lineage-restricted,serve as a cellular reserve to foster development and maintain skeletal *** categorized within the broader mesenchymal stromal/stem cells(MSCs).

关键词： skeletal involvement maintain