检索结果-南通市图书馆

Etching-free pixel definition in InGaN green micro-LEDs

Light(Science & Applications) 2024年第8期13卷 1655-1665页

作者： Zhiyuan Liu Yi Lu Haicheng cao Glen isaac Maciel garcia Tingang Liu Xiao Tang Na Xiao Raul Aguileta Vazquez Mingtao Nong Xiaohang Li Advanced Semiconductor Laboratory Electrical and Computer Engineering ProgramCEMSE DivisionKing Abdullah University of Science and Technology(KAUST)Thuwal 23955-6900Kingdom of Saudi Arabia

The traditional plasma etching process for defining micro-LED pixels could lead to significant sidewall *** near sidewall regions act as non-radiative recombination centers and paths for current leakage,significantly deteriorating device *** this study,we demonstrated a novel selective thermal oxidation(STO)method that allowed pixel definition without undergoing plasma damage and subsequent dielectric *** annealing in ambient air oxidized and reshaped the LED structure,such as p-layers and InGaN/GaN multiple quantum ***,the pixel areas beneath the pre-deposited SiO_(2)layer were selectively and effectively *** was demonstrated that prolonged thermal annealing time enhanced the insulating properties of the oxide,significantly reducing LED leakage ***,applying a thicker SiO_(2)protective layer minimized device resistance and boosted device efficiency *** the STO method,InGaN green micro-LED arrays with 50-,30-,and 10-μm pixel sizes were manufactured and *** results indicated that after 4 h of air annealing and with a 3.5-μm SiO_(2)protective layer,the 10-μm pixel array exhibited leakage currents density 1.2×10^(-6)A/cm^(2)at-10 V voltage and a peak on-wafer external quantum efficiency of~6.48%.This work suggests that the STO method could become an effective approach for future micro-LED manufacturing to mitigate adverse LED efficiency size effects due to the plasma etching and improve device ***-LEDs fabricated through the STO method can be applied to micro-displays,visible light communication,and optical interconnect-based *** planar pixel geometry will provide more possibilities for the monolithic integration of driving circuits with ***,the STO method is not limited to micro-LED fabrication and can be extended to design other III-nitride devices,such as photodetectors,laser diodes,high-electron-mobility transistors

关键词： annealing protective quantum

来源：

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

Thermoluminescence characterization of natural and synthetic irradiated ce-monazites

引用

Journal of Rare Earths 2024年第4期42卷 643-650页

作者： V.correcher c.Boronat J.garcia-Guinea J.F.Benavente T.Rivera-Montalvo cIEMAT Av.Complutense 4028040MadridSpain MNcN-cSIc J.Gutierrez Abascal 228006MadridSpain Instituto Politécnico Nacional CICATA-IPNAv.Legaria 694Mexico City11500Mexico

The thermoluminescence(TL)emission of synthetic and natural ce-monazites was characterized here to determine the potential application in the identification of microscopic defects from a qualitative point of view trying to link each TL peak to a chemical-physical *** kinetic parameters that lead the luminescence processes were calculated by means of variable heating rate and computing glow curve deconvolution methods and allow identifying three groups of components at~90,130 and 290℃(for the mineral sample)and~90,170,220,270 and 320℃(for the synthetic cePO_(4):Nd_(0.20),La_(0.25)).The main differences appreciated in these complex TL curves are mainly due to(i)the content of impurities(natural sample contains lanthanides as well as U 0.60%and Th 5.22%)and(ii)the degree of crystallinity of the samples which is directly related to the type of impurities(synthetic monazite relies only on Nd and La).The behavior of the dose response in the range of 1-8 Gy is similar for both samples;the TL intensity increases linearly as the dose increases without changes in the position of the maxima,denoting first-order kinetic luminescence *** peak could be mostly associated with structural defects(i.e.,phase transitions),chemical reactions(i.e.,ce3+?ce4+redox reaction,dehydration or dehydroxylation processes)or intrinsic defects(i.e.,Frenkel defects,ODcs or NBOHcs).

关键词： Thermoluminescence Kineticparameters Phosphate ce-monazite Defects Rare earths

来源：

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

New pearlitic steels for 21st century rail applications

引用

Baosteel Technical Research 2010年第S1期4卷 59-页

作者： R ORDONEZ c isaac garcia Semih KALAY Anthony J DEARDO The Basic Metals Processing Research Institute Department of Mechanical Engineering and Materials Science University of Pittsburgh PittsburghPennsylvania 15261USA Transportation Technology corporation Inc PuebloCO 81001 Department of Mechanical Engineering University of Oulu P.O.Box 4200(Linnanmaa) FIN-90014Finland

To improve competitiveness,the nation's railroads have increased the axle loads and speed of the *** has led to a rapid decrease in the life expectancy of premium rails through accelerated wear,rolling contact fatigue and *** counter this effect,the railroads need rails that exhibit better performance in these areas.A research program has been initiated to study the microstructural aspects of near-eutectoid steels that would improve these *** first phase of the work was to carefully characterize the existing commercial rail steels in terms of pearlite interlamellar spacing,steel cleanliness and the presence of pro-eutectoid cementite on prior-austenite *** characterizations were then correlated with both mechanical properties and overall rail *** second phase of the program was to develop a better microstructure through control of composition,thermomechanical processing and cooling *** was achieved through the use of laboratory-melted heats of experimental near-eutectoid compositions and a computer controlled MTS compression machine modified for axisymmetric compression testing and subsequent controlled *** optimum processing route for these new steels has been determined,and pilot-scale heats have been melted,hot rolled and cooled using the information gained from the MTS *** mechanical properties of these new steels have been determined and the rail performance tests are being conducted using laboratory-scale ***,these new rail steels will be tested under commercial conditions on the TTcI test track in Pueblo,*** paper will report on the alloy and processing design and resulting properties of the steels developed in this research *** for future rail compositions and processing to obtain improved properties and performance will be presented.

关键词： rail steels interlamellar spacing pearlite colony pro-eutectoid cementite

来源：

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

DeepRice: A deep learning and deep feature based classification of Rice leaf disease subtypes

引用

ARTIFIcIAL INTELLIGENcE IN AGRIcULTURE 2024年第1期11卷 34-49页

作者： Ritharson, P. isaac Raimond, Kumudha Mary, X. Anitha Robert, Jennifer Eunice Andrew, J. Karunya Inst Technol & Sci Dept CSE Coimbatore Tamilnadu India Karunya Inst Technol & Sci Dept Robot Engn Coimbatore India Manipal Acad Higher Educ Manipal Inst Technol Dept Mechatron Engn Manipal 576104 Karnataka India Manipal Acad Higher Educ Manipal Inst Technol Dept Comp Sci & Engn Manipal 576104 Karnataka India

Rice stands as a crucial staple food globally, with its enduring sustainability hinging on the prompt detection of rice leaf diseases. Hence, efficiently detecting diseases when they have already occurred holds paramount importance for solving the cost of manual visual identification and chemical testing. In the recent past, the identification of leaf pathologies in crops predominantly relies on manual methods using specialized equipment, which proves to be time-consuming and inefficient. This study offers a remedy by harnessing Deep Learning (DL) and transfer learning techniques to accurately identify and classify rice leaf diseases. A comprehensive dataset comprising 5932 self-generated images of rice leaves was assembled along with the benchmark datasets, categorized into 9 classes irrespective of the extent of disease spread across the leaves. These classes encompass diverse states including healthy leaves, mild and severe blight, mild and severe tungro, mild and severe blast, as well as mild and severe brown spot. Following meticulous manual labelling and dataset segmentation, which was validated by horticulture experts, data augmentation strategies were implemented to amplify the number of images. The datasets were subjected to evaluation using the proposed tailored convolutional Neural Networks models. Their performance are scrutinized in conjunction with alternative transfer learning approaches like VGG16, Xception, ResNet50, DenseNet121, Inception ResnetV2, and Inception V3. The effectiveness of the proposed custom VGG16 model was gauged by its capacity to generalize to unseen images, yielding an exceptional accuracy of 99.94%, surpassing the benchmarks set by existing state-of-the-art models. Further, the layer wise feature extraction is also visualized as the interpretable AI. (c) 2023 The Authors. Publishing services by Elsevier B.V. on behalf of KeAi communications co., Ltd. This is an open access article under the cc BY-Nc-ND license (http://creativeco

关键词： Rice leaf disease Deep learning cNN crop yield Agriculture Food security IDENTIFIcATION

来源：

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

Systematic Radio Telescope Alignment Using Portable Fringe Projection Profilometry

引用

Nanomanufacturing and Metrology 2024年第1期7卷 75-85页

作者： Joel Berkson Justin Hyatt Nathan Julicher Byeongjoon Jeong isaac Pimienta Rachel Ball Wyatt Ellis Jason Voris Diego Torres‑Barajas Daewook Kim James c.Wyant college of Optical Sciences University of Arizona1630 E.University Blvd.TucsonAZ 85721USA Department of Astronomy at Steward Observatory University of Arizona933 N Cherry Ave.TucsonAZ 85721USA

In 2019,the Event Horizon Telescope(EHT)released the first-ever image of a black hole event *** are now aiming for higher angular resolutions of distant targets,like black holes,to understand more about the fundamental laws of gravity that govern our *** achieve this higher resolution and increased sensitivity,larger radio telescopes are needed to operate at higher frequencies and in larger *** like the next-generation Very Large Array(ngVLA)and the Square-Kilometer Array(SKA)require building hundreds of telescopes with diameters greater than 10 ms over the next *** has a twofold *** telescope surfaces need to be more accurate to operate at higher frequencies,and the logistics involved in maintaining a radio telescope need to be simplified to support them properly in large *** of these problems can be solved with improved methods for surface metrology that are faster and more accurate with a higher *** leads to faster and more accurate panel alignment and,therefore,a more productive *** this paper,we present the use of binocular fringe projection profilometry as a solution to this problem and demonstrate it by aligning two panels on a 3-m radio telescope *** measurement takes only 10 min and directly delivers feedback on the tip,tilt,and piston of each panel to create the ideal reflector shape.

关键词： Metrology Fringe projection profilometry Off-axis alignment Radio astronomy Radio antenna

来源：

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

characterization of Small-Scale Farmers and Assessment of Their Access to crop Production Information in Selected counties of Kenya

引用

Agricultural Sciences 2024年第5期15卷 565-589页

作者： Anastasia Mumbi Wahome John B. K. Kiema Galcano c. Mulaku isaac Mukoko Department of Geospatial & Space Technology University of Nairobi Nairobi Kenya Department of Public Health Kenya Methodist University Nairobi Kenya

Small-scale farming accounts for 78% of total agricultural production in Kenya and contributes to 23.5% of the country’s GDP. Their crop production activities are mostly rainfed subsistence with any surplus being sold to bring in some income. Timely decisions on farm practices such as farm preparation and planting are critical determinants of the seasonal outcomes. In Kenya, most small-scale farmers have no reliable source of information that would help them make timely and accurate decisions. county governments have extension officers who are mandated with giving farmers advisory services to farmers but they are not able to reach most farmers due to facilitation constraints. The mode and format of sharing information is also critical since it’s important to ensure that it’s timely, well-understood and usable. This study sought to assess access to geospatial derived and other crop production information by farmers in four selected counties of Kenya. Specific objectives were to determine the profile of small-scale farmers in terms of age, education and farm size;to determine the type of information that is made available to them by county and Sub-county extension officers including the format and mode of provision;and to determine if the information provided was useful in terms of accuracy, timeliness and adequacy. The results indicated that over 80% of the farmers were over 35 years of age and over 56% were male. Majority had attained primary education (34%) or secondary education (29%) and most farmers in all the counties grew maize (71%). Notably, fellow farmers were a source of information (71%) with the frequency of sharing information being mostly seasonal (37%) and when information was available (43%). Over 66% of interviewed farmers indicating that they faced challenges while using provided information. The results from the study are insightful and helpful in determining effective ways of providing farmers with useful information to ensure maximum benefits.

关键词： Small Scale Farmers Farmers crop Production Information Services Geospatial Information Information Access

来源：

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

Design and Development of a Parabolic Trough Solar Air Heater for a Greenhouse Dryer

引用

Journal of Power and Energy Engineering 2024年第9期12卷 1-18页

作者： Eric King’ori isaac N. Simate Department of Mechanical Engineering The University of Zambia Lusaka Zambia Department of Agricultural Engineering The University of Zambia Lusaka Zambia

Design and Development of a Parabolic Trough Solar Air Heater (PTSAH) for a Greenhouse Dryer (GD) was done to improve the dryer’s performance. The materials used for the fabrication of the PTSAH included galvanized sheets covered with aluminium foil, an absorber tube made of GI pipe painted matt black to increase heat absorbance at the focal line, mild steel square tubes, shutter plywood, and an axial fan to push air through the absorber tube. Key geometrical parameters used for the design of the PTSAH were a rim angle of 98 degrees, focal length of 0.2608 m, height of 0.3451 m, length of 2 m, and an aperture width of 1.2 m. The PTSAH’s total aperture surface area was 2.4 m2, while its absorber tube surface area was 0.1587 m2. The PTSAH was experimentally tested to establish its thermal performance. It was found that the ambient air recorded an average value of 31.1˚c and that the air heater could increase the air temperature by 45.6˚c above ambient with a thermal efficiency of 5.3%. It can, therefore, be concluded that the PTSAH can significantly improve the performance of a GD by supplying the GD with air at a higher temperature than ambient.

关键词： Solar Air Heater Greenhouse Dryer Parabolic Trough Thermal Performance

来源：

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

The effect of abiotic stresses on plant c:N:P homeostasis and their mitigation by silicon

引用

The crop Journal 2024年第2期12卷 340-353页

作者： Milton garcia costa Renato de Mello Prado Luiz Fabiano Palaretti Jonas Pereira de Souza Júnior Department of Agricultural Production Science School of Agricultural and Veterinarian SciencesSão Paulo State UniversityJaboticabalBrazil

In crop plants, various environmental stresses affect the balance of carbon, nitrogen, and phosphorus(c:N:P), leading to biochemical and physiological alterations and reductions in yield. Silicon(Si) is a beneficial element that alleviates plant stress. Most studies involving silicon have focused on physiological responses, such as improvements in photosynthetic processes, water use efficiency, and antioxidant defense systems. But recent research suggests that stressed plants facing either limited or excessive resources(water, light, nutrients, and toxic elements), strategically employ Si to maintain c:N:P homeostasis, thereby minimizing biomass losses. Understanding the role of Si in mitigating the impact of abiotic stresses on plants by regulating c:N:P homeostasis holds great potential for advancing sustainable agricultural practices in crop production. This review presents recent advances in characterizing the influence of environmental stresses on c:N:P homeostasis, as well as the role of Si in preserving c:N:P equilibrium and attenuating biological damage associated with abiotic stress. It underscores the beneficial effects of Si in sustaining c:N:P homeostasis and increasing yield via improved nutritional efficiency and stress mitigation.

关键词： Nutritional stoichiometry Elemental stoichiometry Beneficial element Environmental stresses Nutritional efficiency carbon use efficiency Agricultural sustainability

来源：

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

Synthesis of coral-like structures of Pr-Yb co-doped YIG: Structural,optical, magnetic and antimicrobial properties

引用

Journal of Rare Earths 2024年第3期42卷 543-554,I0004页

作者： A.Fernandez Francisca P.Araujo Y.Guerra S.castro-Lopes J.Matilla-Arias Idglan S.de Lima Edson c.Silva-Filho Josy A.Osajima F.Guerrero R.Pena-garcia Federal University of Piau Graduate Program in Materials Science and EngineeringTeresinaPIBrazil Federal Rural University of Pernambuco Academic Unit of Cabo de Santo AgostinhoCabo de Santo AgostinhoPEBrazil Federal University of Piaui Department of PhysicTeresinaPBrazil Federal University of Pernambuco Graduate Program in Materials ScienceRecifePEBrazil University of Granma Departmentof Basic Sciences and Applied InformaticsFaculty of Technical SciencesBayamoCuba Federal University of Amazonas Department of PhysicManausAMBrazil Federal University of Pernambuco Department of PhysicRecifePEBrazil

coral-like structures of the Y_(3-x)Pr_(x)Fe_(5-y)Yb_(y)O_(12),(0.00 ≤ x ≤ 0.04, 0.00 ≤ y ≤ 0.02) compound were synthesized using the sol-gel method. Structural investigation certified the YIG cubic crystal structure formation, without any secondary phase. It is shown that, the relatively large ionic radius of the dopant cations results in an expansion of the lattice parameter, variations in the Iona-O-Iondangle, Iona-O,Iond-O and Ionc-O bond distances and decrease in the average crystallite size. Fourier transform infrared(FTIR) and Raman measurements are essential to testify the single-phase formation of YIG crystal structure and are observed changes in the stretching and vibrational modes, respectively. The morphological study, energy dispersive spectroscopy(EDS) spectra and textural properties show corallike structures, peaks associated with Pr^(3+) and Yb^(3+) atoms and the effect of dopants on surface area,diameter, and pore volume, respectively. The optical analysis from diffuse reflectance spectra witnessed an increase in the optical gap band, a decrease in Urbach energy and blue shift in the charge transfer,correlated with the expansion of the unit cell due to the dopant's insertion in the YIG structure. A typical ferrimagnetic behavior is exhibited by the Y_(3-x)Pr_(x)Fe_(5-y)Yb_(y)O_(12)compound. The saturation magnetization(M_(s)), cubic anisotropy constant(K_(1)) and coercive field(H_(c)) increase with the Pr^(3+)cations content, as consequence of their magnetic nature and distribution around of Fe^(3+)ions due to the coexistence with the Yb^(3+). Finally, for the first time, antibacterial tests by mean of the direct contact method were performed for YIG co-doped with Pr^(3+)and Yb^(3+)and it is shown that, relatively high dosages of Pr^(3+) cations favored the activity against S. aureus, therefore, a new biological property for YIG doped with rare earths is presented.

关键词： Yttrium iron garnet(YIG) coral-like structures Rare earths Band gap energy Magnetic properties Antimicrobial properties

来源：

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

Photoelectrochemical Iron-catalyzed c(sp^(3))-H Borylation of Alkanes in a Position-Selective Manner

引用

ccS chemistry 2024年第6期6卷 1430-1438页

作者： Wen Wei Bin Wang Simon L.Homölle Jinbin Zhu Yanjun Li Tristan von Münchow isaac Maksso Lutz Ackermann Institut für Organische und Biomolekulare chemie Georg-August-Universität Göttingen37077 Göttingen

catalytic c-H borylation is of prime topical importance,since easily available feedstock chemicals can thereby be transformed into valuable transient functional groups in the absence of directing ***,we disclose an iron-catalyzed c(sp^(3))-H borylation of simple,non-prefunctionalized alkanes,providing access to value-added products in a single step by means of *** power of merging photo-and electrochemistry was mirrored by ample scope and exceedingly mild reaction ***,an outstanding position-selectivity in favor of primary c(sp^(3))-H proved viable within the photoelectrochemical borylation through a chemo-selective anodic overoxidation *** ferro-photoelectrochemistry strategy avoids toxic precious transition metals,enabling c(sp^(3))-H borylations in a site-selective fashion.

关键词： photoelectrocatalysis c(sp^(3))-H borylation iron catalysis position-selectivity chlorine radical

来源：

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

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：