检索结果-南通市图书馆

Low-loss and polarization insensitive 32×4 optical switch for ROADM applications

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

Light(Science & Applications) 2024年第5期13卷 875-884页

作者： Xiaotian Zhu Xiang Wang Yanlu Huang Liyan Wu Chunfei Zhao Mingzhu Xiao Luyi Wang Roy davidson Yanni Ou Brent E.Little Sai T.Chu Department of Physics City University of Hong KongTat Chee AvenueHong KongChina. QXP Technologies Inc. NO.15th Shanglinyuan 1st RoadXi’anShaanxi 710119China. State Key Laboratory of Information of Photonics and Optical Communications School of Electronic EngineeringBeijing University of Posts and TelecommunicationsBeijing 100876China

Integrated switches play a crucial role in the development of reconfigurable optical add-drop multiplexers(ROADMs)that have greater flexibility and compactness,ultimately leading to robust single-chip *** decades of research on switches with various structures and platforms,achieving a balance between dense integration,low insertion loss(IL),and polarization-dependent loss(PDL)remains a significant *** this paper,we propose and demonstrate a 32×4 optical switch using high-index doped silica glass(HDSG)for ROADM *** switch is designed to route any of the 32 inputs to the express ports or drop any channels from 32 inputs to the target 4 drop ports or add any of the 4 ports to any of the 32 express *** switch comprises 188 MachZehnder Interferometer(MZI)type switch elements,88 optical vias for the 44 optical bridges,and 618 waveguidewaveguide crossings with three-dimensional(3D)*** 1550 nm,the fiber-to-fiber loss for each express channel is below 2 dB,and across the C and L bands,below 3 *** each input channel to all 4 drop/add channels at 1550 nm,the loss is less than 3.5 dB and less than 5 dB across the C and L *** PDLs for all express and input channels to the 4 drop/add channels are below 0.3 dB over the C band,and the crosstalk is under−50 dB for both the C and L bands.

关键词： polarization ROADM optical

粉末冶金Al-5.6Zn-2Mg合金在热压缩过程中加工硬化特性及本构模型的比较

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 Central South University 2024年第2期31卷 346-368页

作者： KATIKA Harikrishna DAMODA R.K. davidson M.J. SEETHARAM R. KASAGANI Veera Venkata Nagaraju Department of Mechanical Engineering National Institute of TechnologyWarangal 506004India Department of Mechanical Engineering The Indian Institute of Information Technology Design and ManufacturingKurnool 518007India

在300~5000℃、应变速率为0.1~0.0001 s−1的条件下,在万能试验机上对Al-5.6Zn-2Mg铝合金进行热压缩试验,以确定动态再结晶开始时的加工硬化速率曲线σ_(c)(ε_(c))l以及关键特征σ_(c)(ε_(c))l、σ_(p)(ε_(p))和σ_(ss)与Z系数之间的... 详细信息

在300~5000℃、应变速率为0.1~0.0001 s−1的条件下,在万能试验机上对Al-5.6Zn-2Mg铝合金进行热压缩试验,以确定动态再结晶开始时的加工硬化速率曲线σ_(c)(ε_(c))l以及关键特征σ_(c)(ε_(c))l、σ_(p)(ε_(p))和σ_(ss)与Z系数之间的相关性。使用了四个本构模型,Arrhenius模型、改进的Johnson-Cook模型(MJC)、改进的Zerilli-Armstrong模型(MZA)和开发的人工神经网络(ANN)。结果表明,ANN型模型和Arrhenius模型的相对误差的绝对平均值最低,分别为0.486%和3.36%,MZA型模型和MJC型模型的相对误差的绝对平均值较高,分别为8.84%和3.93%。由于Arrhenius模型能够处理各种因素之间的非线性关系,因此它被认为是最合适的预测模型,但在材料性质未知或实验数据有限的情况下,MJC模型可能是一种更简单的替代方法。MZA模型不适合估计热压缩时的流变应力。此外,训练最好的神经网络模型的预测性能最好,相对误差的绝对平均值为0.486%,R值为0.99。

关键词：加工硬化速率曲线本构建模热压缩 EBSD分析流变曲线

What Makes Homeowners Consider Protective Actions to Reduce Disaster Risk?An Application of the Precaution Adoption Process Model and Life Course Theory

在线全文

学校读者我要写书评

暂无评论

International Journal of Disaster Risk Science 2021年第3期12卷 312-325页

作者： Alexia Stock rache. a.davidson Joseph E.Trainor rache. Slotter Linda K.Nozick Jamie B.Kruse Department of Civil and Environmental Engineering University of DelawareNewarkDE 19711USA Department of Civil and Environmental Engineering University of DelawareNewarkDE 19716USA School of Public Policy and Administration University of DelawareNewarkDE 19716USA Disaster Science and Management University of DelawareNewarkDE 19716USA School of Civil and Environmental Engineering Cornell UniversityIthacaNY 14853USA Department of Economics East Carolina UniversityGreenvilleNC 27858USA

We hypothesize that for disaster risk mitigation,many households,despite being aware of their risk and possible mitigation actions,never seriously consider doing anything about *** mitigation-focused decisions,since there is no equivalent to warning messages,the decision process is likely to evolve over an extended *** explore what activates hurricane mitigation protective action decisions through three research questions:(1)to what extent are homeowners unengaged in protective action decision making?(2)What homeowner characteristics are associated with lack of engagement?And(3)to what extent do different life events trigger engagement in the decision-making process?We use the Precaution Adoption Process Model to conceptualize engagement as distinct from decision making;the broader protective action decision-making literature to explore drivers of engagement;and Life Course Theory to examine potential transitions from unengaged to *** use survey data of homeowners in North Carolina to examine these questions *** suggest that one-third of respondents had never engaged in protective action decisions,that life experiences differ in their occurrence frequency and effect on households’mitigation decisions,and that some events,such as renovating,reroofing,or purchasing a home may offer critical moments that could be leveraged to encourage greater engagement in mitigation decision making.

关键词： Homeowners Hurricane damage Life course theory Mitigation decisions North Carolina Protective action

Are there sex-based disparities in cataract surgery?

在线全文

学校读者我要写书评

暂无评论

International Journal of Ophthalmology(English edition) 2024年第1期17卷 137-143页

作者： Matthew D.Geiger Anne M.Lynch Alan G.Palestine Nathan C.Grove Karen L.Christopher Richard S.davidson Michael J.Taravella Naresh Mandava Jennifer L.Patnaik Department of Ophthalmology University of Colorado School of MedicineAuroraCO 80045USA

AIM:To investigate sex-based differences in the occurrence of intra-operative and post-operative complications and associated visual outcomes following cataract ***:This was a retrospective study of patients who had phacoemulsification cataract surgery at the University of Colorado School of *** collected included the patient’s health history,ocular comorbidities,operative and post-operative complications,and the post-operative best corrected visual acuity(BCVA).The data were analyzed using univariate and multivariable logistic regression with generalized estimating equations to account for the correlation of some patients having two eyes included in the ***:A total of 11977 eyes from 7253 patients were included in the *** comorbidities differed by sex,with males having significantly higher percentages of traumatic cataracts(males 0.7%vs females 0.1%),prior ocular surgery(6.7%vs 5.5%),and mature cataracts(2.8%vs 1.9%).Conversely,females had significantly higher rates of pseudoexfoliation(2.0%vs 3.2%).In unadjusted analysis,males had higher rates of posterior capsular rupture(0.8%vs 0.4%)and vitreous loss(1.0%vs 0.6%),but this difference was not significant after adjustment for *** had a significantly increased risk of post-operative retinal detachment,but in multivariable analysis this was no longer *** were significantly less likely to undergo post-operative neodymium-doped yttrium aluminum garnet(Nd:YAG)laser capsulotomy for posterior capsule opacification(OR=0.8,95%CI=0.7-0.9,P=0.0005).The BCVA was slightly worse for males pre-operatively;but post-operatively,both sexes exhibited similar visual acuity of Snellen equivalent 20/***:The study finds that in a cohort of patients presenting for cataract surgery,sex differences exist in pre-operative comorbidities and surgical characteristics that contribute to higher rates of some complications for ***,observed surgical complicatio

关键词： cataract surgery sex-based disparity phacoemulsification outcomes

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

节日贺卡

中学生英语 2024年第11期 16-19页

作者： Jacqueline davidson Kopito 梁小明(译) 不详湖北武汉电力职业技术学院

那是离假期还有两周的时候,我还没有寄出我的节日贺卡。每年,我家都会从朋友那里收到几十张节日贺卡,那年我也想寄一张。我们会收到各种各样的贺卡,比如全家的照片、孩子的照片、度假照片,甚至是专业制作的照片。有时我们收到的贺卡上... 详细信息

那是离假期还有两周的时候,我还没有寄出我的节日贺卡。每年,我家都会从朋友那里收到几十张节日贺卡,那年我也想寄一张。我们会收到各种各样的贺卡,比如全家的照片、孩子的照片、度假照片,甚至是专业制作的照片。有时我们收到的贺卡上根本没有图片,只是用明亮、粗体的字母祝我们节日快乐。经过思考,我决定选择专业摄影师拍摄的全家福。把我的两个儿子送到学校后,我打电话预约了当地的摄影师。

关键词：专业摄影师贺卡照片打电话

An arthropod community beyond the dry limit of plant life

在线全文

学校读者我要写书评

暂无评论

Journal of Arid Land 2021年第6期13卷 629-638页

作者： Benjamin davidson Elli GRONER Arava Institute for Environmental Studies D.N.Eilot 88840Israel Vassar College PoughkeepsieNew York 12604United States of America Dead Sea and Arava Science Center Mitzpe Ramon 8060000Israel Ben Gurion University Eilat 88556Israel

Water availability,which enables plant growth and animal activity,regulates dryland ecosystem *** hyper-arid ecosystems,rain cannot support vascular plant ***,hyper-arid vegetation is restricted to the lower topography,where runoff ***,food resources originating from areas of dense vegetation are dispersed across the desert floor,enabling animal life in areas lacking vascular plant ***,certain regions,such as the hyper-arid upper topography,may be devoid of plant-derived food *** present study examined arthropod activity in the upper topography of a hyper-arid desert,in comparison with arthropod activity in the lower *** traps were utilized to compare arthropod activity along unvegetated ridges with activity in parallel,vegetated ***,the study revealed dense arthropod communities in the barren upper *** collected in the upper topography represented 26%of total arthropod *** addition,the overlap between arthropod identity in the ridges and wadis(i.e.,riverbeds)was low,and certain arthropods were strongly affiliated with the *** upper topographic communities included high numbers of silverfish(Zygentoma:Lepismatidae),malachite beetles(Psiloderes),and predatory mites(Acari:Anystidae),and these arthropods were present at various life *** remains unclear how arthropod communities can persist in the unvegetated upper topography of the hyper-arid study *** results raise the possibility that other food sources,independent from vascular plants,may play a significant role in the life history of hyper-arid arthropods.

关键词： hyper-arid area spatial distribution topography silverfish Tenebrionidae desert

The enhanced element enrichment in the supercritical states of granite–pegmatite systems

在线全文

学校读者我要写书评

暂无评论

Acta Geochimica 2019年第3期38卷 335-349页

作者： Rainer Thomas Paul davidson Karen Appel Section 3.6.Chemistry and Physics of Earth Materials Helmholtz-Centre Potsdam German Research Centre for Geoscience – GFZ CODES Centre for Ore Deposit and Earth Sciences School of Natural Sciences University of Tasmania High Energy Density scientific instrument European X-Ray Free-Electron Laser Facility GmbH

In this paper, we show that supercritical fluids have a greater significance in the generation of pegmatites,and for ore-forming processes related to granites than is usually assumed. We show that the supercritical melt or fluid is a silicate phase in which volatiles; principally H_2O are completely miscible in all proportions at magmatic temperatures and pressures. This phase evolves from felsic melts and changes into hydrothermal fluids, and its unique properties are particularly important in sequestering and concentrating low abundance elements, such as metals. In our past research, we have focused on processes observed at upper crustal levels, however extensive work by us and other researchers have demonstrated that supercritical melt/fluids should be abundant in melting zones at deep-crustal levels too. We propose that these fluids may provide a connecting link between lower and upper crustal magmas,and a highly efficient transport mechanism for usually melt incompatible elements. In this paper, we explore the unique features of this fluid which allow the partitioning of variouselements and compounds, potentially up to extreme levels,and may explain various features both of mineralization and the magmas that produced them.

关键词： Granites Pegmatites Supercritical state Extreme element enrichment

The Challenges of the Virtual Classroom——The Semiotics of Transmedial Literacy in VR Education

在线全文

学校读者我要写书评

暂无评论

Language and Semiotic Studies 2021年第4期7卷 1-25页

作者： Kyle davidson University of Tartu Estonia

In 2020,the global COVID-19 pandemic required a significant number of students to move their education online,via digital *** use of virtual learning environments,combined with virtual reality technology and avatars,has demonstrated the convergence of current technology and ***,embodiment,and social reality construction are increasingly transmediated,with physical and virtual signs being present for young learners (and their teachers) in their classroom space—for example filters or *** may enable a freedom of expression for some students,offering the ability to explore and express their inner selves without physical ***,there could be a bias inherent to such technology which exacerbates offline inequality and *** example,access to the technology,or the Anglo-centric nature of programming languages which necessitates some level of English language *** the ability to swap gender may be positive for transgender teens,the ability to change race or age is *** these distinctions are made and understood requires an updated model of digital literacy,focusing on the sociology,and semiotic interpretation,of the signs within the virtual/physical transmediated *** is understood as significant in the context of contemporary,online,young learners,is imperative for future identity construction.

关键词： identity online learning gender transmedia avatar

Bio-Economic Strategy to Combat Non-Point Pollution in China

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2005年第2期15卷 156-163页

作者： B. davidson R.E.WHITE Institute of Land and Food Resources Institute of Land and Food Resources The University of MelbourneParkville Victoria 3010 (Australia)The University of MelbourneParkville Victoria 3010 (Australia)

While non-point pollution from agriculture has become an increasingly serious problem in China, some progress has been made in studying the causal biophysical processes. However, few studies have assessed the economic consequences of non-point pollution in China or the policy options that could be employed to combat it. In this work a sustainable strategy to control non-point pollution from crop production, which involved taxing excessive inputs of irrigation water and fertilizer, was proposed. The approach taken to assess these measures combined biophysical and economic models,having a trade-off between economic returns and an improved environment. A proven and practical spatially referenced water and nutrient management model was used to determine the quantities of excessive irrigation water and fertilizer for specific soil and land use. Also, a set of indicators were proposed for evaluating the effects of agricultural economic output and agricultural practices on the environment.

关键词： crop production integrated biophysical-economic model non-point pollution policy instrument sustainable strategy