检索结果-南通市图书馆

High-efficiency,large-area,topologyoptimized metasurfaces

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) 2019年第1期8卷 749-757页

作者： Thaibao Phan David sell evan W.Wang sage Doshay Kofi Edee Jianji Yang Jonathan A.Fan Department of Electrical Engineering Stanford UniversityStanfordCA 94305USA Department of Applied Physics Stanford UniversityStanfordCA 94305USA Universite Clermont Auvergne Institut PascalBP 10448F-63000 Clermont-FerrandFrance CNRs UMR 6602Institut PascalF-63177 AubiereFrance

Metasurfaces are ultrathin optical elements that are highly promising for constructing lightweight and compact optical *** their practical implementation,it is imperative to maximize the metasurface *** optimization provides a pathway for pushing the limits of metasurface efficiency;however,topology optimization methods have been limited to the design of microscale devices due to the extensive computational resources that are *** introduce a new strategy for optimizing large-area metasurfaces in a computationally efficient *** stitching together individually optimized sections of the metasurface,we can reduce the computational complexity of the optimization from high-polynomial to *** a proof of concept,we design and experimentally demonstrate large-area,high-numerical-aperture silicon metasurface lenses with focusing efficiencies exceeding 90%.These concepts can be generalized to the design of multifunctional,broadband diffractive optical devices and will enable the implementation of large-area,high-performance metasurfaces in practical optical systems.

关键词： topology optimization surface

Effect of Different Etching Time on Fabrication of an Optoelectronic Device Based on GaN/Psi

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 Renewable Materials 2023年第3期11卷 1101-1122页

作者： Haneen D.Jabbar Makram A.Fakhri Mohammed Jalal Abdul Razzaq Omar s.Dahham evan T.salim Forat H.Alsultany U.Hashim Laser and Optoelectronic Engineering Department University of Technology-IraqBaghdadIraq Department of Civil Engineering College of EngineeringCihan University-ErbilKurdistan RegionIraq Department of Petroleum and Gas Refinery Engineering Al-Farabi University CollageBaghdadIraq Applied science Department University of Technology-IraqBaghdadIraq Department of Medical Physics Al-Mustaqbal University CollegeBabylonIraq Institute of Nano Electronic Engineering University Malaysia PerlisKangarPerlisMalaysia

Gallium nitride(GaN)/porous silicon(Psi)film was prepared using a pulsed laser deposition method and 1064 nm Nd:YAG laser for optoelectronic applications and a series of Psi substrates were fabricated using a photoelectrochemical etching method assisted by laser at different etching times for 2.5–15 min at 2.5 min intervals.X-ray diffraction,room-temperature photoluminescence,atomic force microscopy and field emission scanning electron microscopy images,and electrical characteristics in the prepared GaN on the Psi film were *** optimum Psi substrate was obtained under the following conditions:10 min,10 mA/cm^(2),and 24%hydrofluoric *** substrate exhibited two highly cubic crystalline structures at(200)and(400)orientations and yellow visible band photoluminescence,and homogeneous pores formed over the entire *** pores had steep oval shapes and were accompanied by small dark pores that appeared topographically and *** GaN/Psi film fabricated through PLD exhibited a high and hexagonal crystallographic texture in the(002)*** properties results revealed that the photoluminescence emission of the deposited nano-GaN films was in the ultraviolet band(374 nm)related to GaN material and in the near-infrared band(730 nm)related to the Psi *** topographical and morphological results of the GaN films confirmed that the deposited film contained spherical grains with an average diameter of 51.8 nm and surface roughness of 4.8 *** GaN/Psi surface showed a cauliflower-like morphology,and the built-in voltage decreased from 3.4 to 2.7 eV after *** fabricated GaN/Psi film exhibited good electrical characteristics.

关键词： Gallium nitride porous silicon photoelectrochemical etching pulsed laser deposition optical device

Trauma systems in Canada:striving for quality across an expansive landmass

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Emergency and Critical Care Medicine 2023年第3期3卷 89-93页

作者： Natasha G.Caminsky evan G.Wong Division of General and Trauma surgery McGill UniversityMontrealQuebecCanada

Although Canada has a universal health care program that provides free in-hospital services to all citizens,its vast landmass and nonstandardized prehospital and posthospital systems make delivering quality trauma care challenging,particularly to resource-limited rural *** article summarizes the strengths of the prehospital system,facility-based care,trauma network,trauma registry,rehabilitation,and governance/financing/quality assurance components of Canada’s trauma *** directions,including the use of telemedicine,standardization of practices,and resource optimization,are also ***’s trauma system is well developed,yet geography impedes equitable *** standardization and resource optimization are needed.

关键词： Trauma referral Trauma registry Trauma systems Universal health care

A Hunter-Gatherer Exercise Prescription to Optimize Health and Well-Being in the Modern World

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 science in sport and Exercise 2021年第2期3卷 147-157页

作者： evan L.O’Keefe Carl J.Lavie Ochsner Clinical school The University of Queensland School of MedicineNew OrleansLAUSA Department of Cardiovascular Diseases John Ochsner Heart and Vascular Institute1514 Jefferson HighwayNew OrleansLA 70121-2483USA

There has been considerable innovation and advancement in the field of exercise and physical activity (PA).In regards to the battle against chronic non-communicable disease,however,we believe the model of PA that would prove most salu-tary is one closely mimicking that of our hunter-gatherer *** the purpose of longevity,the human body and our genetic makeup have been evolutionarily adapted to respond best to moderate amounts of high-intensity interval training,in conjunction with high amounts of low intensity ***,to optimize resiliency and cardiorespiratory fitness,a hunter-gatherer fitness regimen must include cross training targeted at flexibility,balance and *** not com-monly understood,the health benefits from exercise comprise a reverse *** endurance athletes residing on the furthest reaches of the PA spectrum appear to lose a substantial portion of the exercise-related longevity and cardiovascular benefits due to cardiac overuse ***,there is an emerging body of evidence suggesting leisure time exercise done with peers in a natural environment is significantly superior to that training done in *** idea of the "power of play" lends support to the ancestral model of PA whereby humans are evolutionary adapted to be highly social,outdoor creatures capable of a diverse range of PA at varying intensities.

关键词： Hunter-gatherer Cardiovascular disease Physical activity Exercise

snapshot Mueller spectropolarimeter imager

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Microsystems & Nanoengineering 2023年第5期9卷 271-279页

作者： Tianxiang Dai Thaibao Phan evan W.Wang soonyang Kwon Jaehyeon son Myungjun Lee Jonathan A.Fan Department of Electrical Engineering Stanford UniversityStanfordCA 94305USA Equipment R&D Team 4 Mechatronics ResearchSamsung Electronics Co.LtdGyeonggi-do 18848Republic of Korea

We introduce an imaging system that can simultaneously record complete Mueller polarization responses for a set of wavelength channels in a single image *** division-of-focal-plane concept combines a multiplexed illumination scheme based on Fourier optics together with an integrated telescopic light-field imaging ***-resolved imaging is achieved using broadband nanostructured plasmonic polarizers as functional pinhole *** recording of polarization and wavelength information on the image sensor is highly *** also develop a calibration approach based on a customized neural network architecture that can produce calibrated measurements in *** a proof-of-concept demonstration,we use our calibrated system to accurately reconstruct a thin film thickness map from a four-inch *** anticipate that our concept will have utility in metrology,machine vision,computational imaging,and optical computing platforms.

关键词： polarization image snapshot

Description of two new species of Hemiphyllodactylus(Reptilia: Gekkonidae) from karst landscapes in Yunnan, China, highlights complex conservation needs

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Zoological Research 2022年第5期43卷 767-786页

作者： Ade Prasetyo Agung Ada Chornelia L.Lee Grismer Jesse L.Grismer evan s.H.Quah Jian-Mei Lu Kyle W.Tomlinson Alice C.Hughes Landscape Ecology Group Center for Integrative ConservationXishuangbanna Tropical Botanical GardenChinese Academy of SciencesMenglunMenglaYunnan 666303China University of Chinese Academy of sciences Beijing 101408China Herpetology Laboratory Department of BiologyLa Sierra UniversityRiversideCalifornia 92515USA Institute for Tropical Biology and Conservation Universiti Malaysia SabahJalan UMSKota KinabaluSabah 88400Malaysia Lee Kong Chian Natural History Museum National University of SingaporeSingapore 117377Singapore Community Ecology and Conservation Group Center for Integrative ConservationXishuangbanna Tropical Botanical GardenChinese Academy of SciencesMenglunMenglaYunnan 666303China school of Biological sciences University of Hong KongPokfulamHong Kong SARChina

Karst habitats are hotspots of diversity and endemism. Their naturally fragmented distributions across broad geographic landscapes have led to the complex array of smaller evolutionary ecosystems that present unique challenges from a conservation *** assessments of karst habitats have revealed that these ecosystems contain an almost unparalleled level of endemism, and many site-restricted species remain undescribed, thus posing considerable challenges for effective conservation *** rock-dwelling species, such as geckos, may be particularly prone to such isolation. In this paper, we discuss one such genus, i.e.,Hemiphyllodactylus, and explore its diversity across karst landforms in Yunnan Province, southwestern China. Based on morphological and genetic data, we describe two new species of Hemiphyllodactylus from karst habitats in simao District and Yanshan County. A phylogenetic tree for Hemiphyllodactylus was constructed using 1?039 base pairs(bp) of the mitochondrial NADH dehydrogenase subunit 2 gene(ND2). The simao and Yanshan specimens can be distinguished from all other congeners within their respective subclades based on uncorrected genetic pairwise distances greater than 6.3% and 4.3%respectively, as well as significant morphological differences. The discovery and description of these two new species brings the total number of described Hemiphyllodactylus species in China to 14and indicates many more undescribed species from unsurveyed karst regions await *** findings suggest that karst ecosystems in Yunnan support a higher diversity of Hemiphyllodactylus than previously *** study also highlights the importance of karst ecosystems as refugia for sitespecific endemic species and the need for heightened conservation efforts.

关键词： Discovery Endemism Geckos Reptiles south China

Effect of pumping chamber on performance of non-overload centrifugal pump

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Journal of Central south University 2015年第8期22卷 2989-2997页

作者：谷云庆牟介刚代东顺郑水华吴登昊蒋兰芳施瀚昱 WANG evan College of Mechanical and Engineering Zhejiang University of Technology Engineering Research Center of Process Equipment and Its Re-manufacturing of Ministry of Education(Zhejiang University of Technology) Zhijiang College Zhejiang University of Technology Institut National Polytechnique of Grenoble Joseph Fourier University

In order to specify the characteristics of un-overloaded centrifugal pumps, the IH100-65-200 pump was chosen as the model pump. Different calculation models for centrifugal pumps were established under different pumping chamber sectional parameters. In the numerical simulation of the centrifugal pumps flow field, the shaft power, head, efficiency, and the changes of the internal flow field under different sectional areas and sectional shapes were studied with the RNG k-ε turbulence model, and the influence of the pumping chamber section characteristics of the non-overloaded centrifugal pumps were analyzed. The results show that sectional areas have a significant impact on the non-overload characteristics of centrifugal pumps. The shaft power and head of centrifugal pump are increasing with a lager sectional area, by which the gradient of head curves decreases. The efficiency is improved under a large flow rate condition, but the head and the efficiency are reduced at a small flow rate. It is also observed that the sectional shapes have less influence on the shaft power, the hydraulic performance and flow field characteristics of a centrifugal pump.

关键词： centrifugal pumps sectional area sectional shape non-overload characteristics numerical simulation

Forecasting shark Attack Risk Using AI: A Deep Learning Approach

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Journal of Data Analysis and Information Processing 2023年第4期11卷 360-370页

作者： evan Valenti safeWaters.AI Boston USA

This study aimed to develop a predictive model utilizing available data to forecast the risk of future shark attacks, making this critical information accessible for everyday public use. Employing a deep learning/neural network methodology, the system was designed to produce a binary output that is subsequently classified into categories of low, medium, or high risk. A significant challenge encountered during the study was the identification and procurement of appropriate historical and forecasted marine weather data, which is integral to the model’s accuracy. Despite these challenges, the results of the study were startlingly optimistic, showcasing the model’s ability to predict with impressive accuracy. In conclusion, the developed forecasting tool not only offers promise in its immediate application but also sets a robust precedent for the adoption and adaptation of similar predictive systems in various analogous use cases in the marine environment and beyond.

关键词： deep learning shark research predictive ai marine biology neural network machine learning shark attacks data science shark biology forecasting

-lormone levels following surgical and medical castration： defining optimal androgen suppression

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Asian Journal of Andrology 2018年第4期20卷 405-406页

作者： Michael T schweizer Michael L Hancock Robert H Getzenberg evan Y Yu Division of Oncology Department of Medicine University of Washington Seattle WA 98116 USA Clinical Research Division Fred Hutchinson Cancer Research Center Seattle WA 98116 USA Veru Healthcare Miami FL 33137 USA

Dear Editor, In the 1940s, Charles Huggins discovered that surgical castration produced remarkable palliative benefits for men with advanced prostate cancer, an effect we now understand to be mediated through deprivi...

关键词：