检索结果-南通市图书馆

OCTOpOD:single-bunch tomography for angular-spectral characterization of laser-driven protons

在线全文

学校读者我要写书评

暂无评论

High power Laser Science and engineering 2023年第6期11卷 16-28页

作者： m.Reimold S.Assenbaum e.Beyreuther e.Bodenstein F.-e.Brack C.eisenmann F.englbrecht F.Kroll F.Lindner U.masood J.pawelke U.Schramm m.Schneider m.Sobiella m.e.p.umlandt m.Vescovi K.Zeil T.Ziegler J.metzkes-Ng Helmholtz-Zentrum Dresden-Rossendorf DresdenGermany Technische Universität Dresden DresdenGermany OncoRay-National Center for Radiation Research in Oncology DresdenGermany Ludwig-maximilians-Universität münchen Garching/MünchenGermany Universitätsklinikum Freiburg FreiburgGermany

Laser-plasma accelerated(LpA)proton bunches are now applied for research fields ranging from ultra-high-dose-rate radiobiology to material ***,the capabilities to characterize the spectrally and angularly broad LpA bunches lag behind the rapidly evolving *** OCTOpOD translates the angularly resolved spectral characterization of LpA proton bunches into the spatially resolved detection of the volumetric dose distribution deposited in a liquid *** to 24 multi-pinhole arrays record projections of the scintillation light distribution and allow for tomographic reconstruction of the volumetric dose deposition pattern,from which proton spectra may be *** the OCTOpOD at a cyclotron,we show the reliable retrieval of various spatial dose deposition patterns and detector sensitivity over a broad dose ***,the OCTOpOD was installed at an LpA proton source,providing real-time data on proton acceleration performance and attesting the system optimal performance in the harsh laser-plasma environment.

关键词： laser-plasma acceleration of protons proton detector tomographic reconstruction

Selection of digital fabrication technique in the construction industry--A multi-criteria decision-making approach

在线全文

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil engineering 2024年第7期18卷 977-997页

作者： m.p.SALAImANImAGUDAm J.JAYApRAKASH Department of Structural and Geotechnical engineering School of Civil EngineeringVellore Institute of TechnologyVellore 632014India

Digital fabrication techniques,in recent decades,have provided the basis of a sustainable revolution in the construction ***,selecting the digital fabrication method in terms of manufacturability and functionality requirements is a complex *** paper presents alternatives and criteria for selection of digital fabrication techniques by adopting the multi-criteria decision-making *** alternatives considered in the study are concrete three-dimensional(3D)printing,shotcrete,smart dynamic casting,material intrusion,mesh molding,injection concrete 3D printing,and thin forming *** criteria include formwork utilization,reinforcement incorporation,geometrical complexity,material enhancement,assembly complexity,surface finish,and build *** demonstrates different multi-criteria decision-making techniques,with both subjective and objective weighting *** given ranking is based on the current condition of digital fabrication in the construction *** study reveals that in the selection of digital fabrication techniques,the criteria including reinforcement incorporation,build area,and geometrical complexity play a pivotal role,collectively accounting for nearly 70% of the overall *** the evaluated techniques,concrete 3D printing emerged as the best performer,however the shotcrete and mesh molding techniques in the second and third positions.

关键词： digital fabrication multicriteria decision-making concrete 3D printing

emission colour tuning in KLnF_(4):Yb^(3+),er^(3+)/Ho^(3+)phosphor

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 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

在线全文

学校读者我要写书评

暂无评论

美国页岩油气地质特征及勘探开发进展

石油勘探与开发 2024年第4期51卷 807-828页

作者： mCmAHON T p LARSON T e ZHANG T SHUSTeR m 美国德克萨斯大学奥斯汀分校杰克逊地质科学学院经济地质局奥斯汀78758-4445德克萨斯州美国

基于美国页岩油气勘探开发历程的回顾,对主要页岩盆地的地质演化、主要页岩层系的油气地质特征及勘探开发进展进行系统梳理和总结。美国重要页岩盆地的富烃页岩主要发育于6个地质时期:中奥陶世、中—晚泥盆世、早石炭世(中—晚密西西比... 详细信息

基于美国页岩油气勘探开发历程的回顾,对主要页岩盆地的地质演化、主要页岩层系的油气地质特征及勘探开发进展进行系统梳理和总结。美国重要页岩盆地的富烃页岩主要发育于6个地质时期:中奥陶世、中—晚泥盆世、早石炭世(中—晚密西西比世)、早二叠世、晚侏罗世和晚白垩世(塞诺曼期—土伦期),构造沉积环境主要包括克拉通内盆地、前陆盆地和被动大陆边缘盆地。古生界富烃页岩主要分布于以下6个盆地:阿巴拉契亚盆地(尤蒂卡页岩和马塞勒斯页岩)、阿纳达科盆地(伍德福德页岩)、威利斯顿盆地(巴肯页岩)、阿卡马盆地(费耶特维尔页岩)、沃思堡盆地(巴内特页岩)和二叠盆地(狼营组和斯帕瑞组/骨泉组页岩)。中生界富烃页岩主要发育在西墨西哥湾盆地(海恩斯维尔组和鹰滩组)和落基山盆地群(以丹佛和粉河盆地的尼尔布拉勒组页岩为主)。通过对各页岩区带的详细分析发现,页岩的岩相和矿物成分存在差异,“页岩储层”并非只是页岩,很多情况下页岩油气还产自粉砂岩和碳酸盐岩等多种岩石类型。美国的页岩油气资源丰富,页岩油地质资源量超过0.246×1012 t,页岩气地质资源量超过290×1012 m3。在开启“页岩革命”的水平井水力压裂技术出现之前,美国经过了长达20年的勘探开发实践和理论技术积累。自2007年至2023年,美国页岩油气产量从约11.2×104t/d油当量增加到超过300.0×104t/d油当量,2017年页岩油气产量超过了常规油气,2023年在油气总产量中的占比增加到60%以上。页岩油气的开发主要得益于钻完井技术的改进,“立体开发”的攻关,以及重复压裂、提高原油采收率和“U”形井等技术的应用。基于美国丰富的页岩资源基础和技术的不断进步,页岩油气的产量将继续为全美的油气生产做出更大贡献。

关键词：美国页岩油页岩气页岩储层非常规储层油气产量资源评价

Impact of device resistances in the performance of graphene‑based terahertz photodetectors

在线全文

学校读者我要写书评

暂无评论

Frontiers of Optoelectronics 2024年第2期17卷 87-97页

作者： O.Castelló Sofía m.López Baptista K.Watanabe T.Taniguchi e.Diez J.e.Velázquez-pérez Y.m.meziani J.m.Caridad J.A.Delgado-Notario Department of Applied physics University of Salamanca37008 SalamancaSpain Unidad de excelencia en Luz y materia estructurada(LUmeS) University of Salamanca37008 SalamancaSpain Research Center for electronic and Optical materials National Institute for Materials Science1-1 NamikiTsukuba 305-0044Japan Research Center for materials Nanoarchitectonics National Institute for Materials Science1-1 NamikiTsukuba 305-0044Japan Nanotechnology Group USAL-NanolabUniversity of Salamanca37008 SalamancaSpain

In recent years,graphene field-effect-transistors(GFeTs)have demonstrated an outstanding potential for terahertz(THz)photodetection due to their fast response and *** features are essential to enable emerging THz applications,including 6G wireless communications,quantum information,bioimaging and ***,the overall performance of these photodetectors may be utterly compromised by the impact of internal resistances presented in the device,so-called access or parasitic *** this work,we provide a detailed study of the influence of internal device resistances in the photoresponse of high-mobility dual-gate GFeT *** dual-gate architectures allow us to fine tune(decrease)the internal resistance of the device by an order of magnitude and consequently demonstrate an improved responsivity and noise-equivalent-power values of the photodetector,*** results can be well understood by a series resistance model,as shown by the excellent agreement found between the experimental data and theoretical *** findings are therefore relevant to understand and improve the overall performance of existing high-mobility graphene photodetectors.

关键词： Graphene THz photodetector Field-effect transistor plasmonic

enhanced quantum resources via two distant atom-cavity systems under the influence of atomic dissipation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Theoretical physics 2024年第2期76卷 62-73页

作者： m Setodeh Kheirabady m K Tavassoly m Rafeie e Ghasemian Laser and Optics Group Faculty of PhysicsYazd UniversityYazd 89195-741Iran Department of electrical engineering Faculty of Intelligent Systems Engineering and Data SciencePersian Gulf UniversityBushehrIran

Quantum resources such as entanglement and coherence are the holy grail for modern quantum technologies. Although the unwanted environmental effects tackle quantum information processing tasks, suprisingly these key quantum resources may be protected and even enhanced by the implementation of some special hybrid open quantum systems. Here, we aim to show how a dissipative atom-cavity-system can be accomplished to generate enhanced quantum *** do so, we consider a couple of dissipative cavities, where each one contains two effective two-level atoms interacting with a single-mode cavity field. In practical applications, a classical laser field may be applied to drive each atomic subsystem. After driving the system, a Bell-state measurement is performed on the output of the system to quantify the entanglement and coherence. The obtained results reveal that the remote entanglement and coherence between the atoms existing inside the two distant cavities are not only enhanced, but can be stabilized, even under the action of dissipation. In contrast, the local entanglement between two atoms inside each dissipative cavity attenuates due to the presence of unwanted environmental ***, the local coherence may show the same behavior as the remote ***, the system provides the steady state entanglement in various interaction regimes,particularly in the strong atom-cavity coupling and with relatively large detuning. more interestingly, our numerical analyses demonstrate that the system may show a memory effect due to the fact that the death and revival of the entanglement take place during the interaction. Our proposed model may find potential applications for the implementation of long distance quantum networks. In particular, it facilitates the distribution of quantum resources between the nodes of large-scale quantum networks for secure communication.

关键词： remote entanglement and coherence atomic dissipation steady state entanglement Bell-statemeasurement

BaTiO3 solid solutions co-doped with Gd3+ and eu3+:Synthesis,structural evolution and dielectric properties

在线全文

学校读者我要写书评

暂无评论

Journal of Rare earths 2024年第10期42卷 1920-1926页

作者： R.martínez-López m.pérez-Labra J.A.Romero-Serrano F.R.Barrientos-Hernández m.Reyes-pérez m.I.Valenzuela-Carrillo G.Urbano-Reyes V.e.Reyes-Cruz G.I.Dávila-pulido Academic Area of earth Sciences and materials Autonomous University of Hidalgo State metallurgy and materials Department ESIQIE-IPNUPALM Autonomous University of Coahuila Boulevard Adolfo López Mateos S/n

In this paper,the synthesis,structural evolution,and dielectric properties of BaTiO3solid solutions codoped with rare earth elements(Gd3+and eu3+) prepared using the solid-state reaction method are *** pure precursor powders of BaCl3,TiO2,Gd2O3,and eu2O3were mixed in stoichiometric proportions,ground in an agate mortar before being uniaxially pressed at 250 mpa and sintered at 1300℃ in air atmosphere for 6 h to obtain Ba1-3xGd2xTi1-3xeu4xO3（x=0,0.0015,0.01 and0.1）.X-ray diffraction（XRD） and Rietveld's refinement results reveal the crystal phase ferroelectric tetragonal BaTiO3for the samples with x=0,0.0015 and 0.01, as well as a consistent increment in the lattice parameters caused by the *** solubility limit of Gd3+and eu3+in the BaTiO3structure is reached for the sample with x>0.01,and the orthorhombic eu2TiO5and monoclinic BaTi2O5secondary phases were *** Raman results show the characteristic peaks of ferroelectric tetragonal BaTiO3around 716 cm-1（LO of A1 symmetry）,515 cm-1（TO of A1 symmetry）,and 305 cm-1（B1）.The maximum relative permittivity measured at 1 kHz was recorded to be 6151.8 for the sample with x=0.0015,and a decrease in the Curie temperature to 105℃ with respect to the undoped sample was *** punctual microanalysis for the samples with x=0.0015,0.01,and 0.1 reveals grains composed of Ba,Ti,O,Gd,and eu homogeneously distributed in the *** Ba/Ti ratios for samples with x=0.0015,0.01 and 0.1 are 2.86,2.91,and 0.68,respectively,indicating substitution at the Ti site for samples with x=0.0015 and 0.01 and a substitution at the Ba site for the sample with x=0.1.

关键词： BaTiO3 Doping europium Gadolinium Rare earths Synthesis

Novel Framework for an Intrusion Detection System Using multiple Feature Selection methods Based on Deep Learning

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2024年第4期29卷 948-958页

作者： A.e.m.eljialy mohammed Yousuf Uddin Sultan Ahmad Department of Information Systems College of Computer Engineering and SciencesPrince Sattam Bin Abdulaziz UniversityAlkharjSaudi Arabia Department of Computer Science College of Computer Engineering and SciencesPrince Sattam Bin Abdulaziz UniversityAlkharjSaudi Arabiaand also with University Center for Research and Development(UCRD)Department of Computer Science and EngineeringChandigarh UniversityPunjabIndia

Intrusion detection systems (IDSs) are deployed to detect anomalies in real time. They classify a network’s incoming traffic as benign or anomalous (attack). An efficient and robust IDS in software-defined networks is an inevitable component of network security. The main challenges of such an IDS are achieving zero or extremely low false positive rates and high detection rates. Internet of Things (IoT) networks run by using devices with minimal resources. This situation makes deploying traditional IDSs in IoT networks unfeasible. machine learning (mL) techniques are extensively applied to build robust IDSs. many researchers have utilized different mL methods and techniques to address the above challenges. The development of an efficient IDS starts with a good feature selection process to avoid overfitting the mL model. This work proposes a multiple feature selection process followed by classification. In this study, the Software-defined networking (SDN) dataset is used to train and test the proposed model. This model applies multiple feature selection techniques to select high-scoring features from a set of features. Highly relevant features for anomaly detection are selected on the basis of their scores to generate the candidate dataset. multiple classification algorithms are applied to the candidate dataset to build models. The proposed model exhibits considerable improvement in the detection of attacks with high accuracy and low false positive rates, even with a few features selected.

关键词： random forest feature selection decision tree software-defined network logistic regression intrusion detection system XGB classifier AdaBoost

Seismic response of deep circular tunnels subjected to S-waves:Axial bending

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Underground Space 2024年第4期17卷 267-279页

作者： Chatuphat Savigamin Antonio Bobet Osvaldo p.m.Vitali HR engineering Services Inc.MedleyFL 33166United States Lyles School of Civil engineering Purdue UniversityWest LafayetteIN 47907United States Department of Civil Environmentaland Construction EngineeringUniversity of Hawaii at ManoaHonoluluHI 96822United States

Ovaling deformation of circular tunnels has received great interest from the tunneling community because this mode of seismicinduced deformation is considered the most ***,there is growing evidence that other deformation modes can also be important and thus need to be considered in *** study presents a new analytical solution to estimate axial bending(snaking),a mode of deformation caused by S-waves impinging on a tunnel parallel to the tunnel *** solution is developed using the soilstructure interaction approach with the assumption that the interface between the ground and the tunnel lining is frictionless(fullslip).Full dynamic numerical simulations are conducted to verify the new full-slip solution,together with the existing no-slip *** of dynamic amplification are also explored for both full-slip and no-slip interface conditions by changing the wavelength(or frequency)of the seismic input motions.

关键词： Seismic response of tunnels Analytical solutions Soil-structure interaction Axial bending Snaking S-waves