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Simple method for extracting the seasonal signals of photochemical reflectance index and normalized difference vegetation index measured using a spectral reflectance sensor

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Journal of Integrative Agriculture 2021年第7期20卷 1969-1986页

作者： Jae-Hyun ryu Dohyeok OH Jaeil CHO Department of Applied Plant Science Chonnam National UniversityGwangju 61186Republic of Korea

A spectral reflectance sensor(SRS)fixed on the near-surface ground was developed to support the continuous monitoring of vegetation indices such as the normalized difference vegetation index(NDVI)and photochemical reflectance index(PRI).NDVI is useful for indicating crop growth/phenology,whereas PRI was developed for observing physiological ***,the seasonal change patterns of NDVI and PRI are two valuable pieces of information in a crop-monitoring ***,capturing the seasonal patterns is considered challenging because the vegetation index values estimated by the reflection from vegetation are often governed by meteorological conditions,such as solar irradiance and ***,unlike growth/phenology,the physiological condition has diurnal changes as well as seasonal *** study proposed a novel filtering method for extracting the seasonal signals of SRS-based NDVI and PRI in paddy rice,barley,and ***,the measurement accuracy of SRSs was compared with handheld spectrometers,and the R^(2)values between the two devices were 0.96 and 0.81 for NDVI and PRI,***,the experimental study of threshold criteria with respect to meteorological variables(i.e.,insolation,cloudiness,sunshine duration,and precipitation)was conducted,and sunshine duration was the most useful one for excluding distorted values of the vegetation *** data processing based on sunshine duration,the R^(2)values between the measured vegetation indices and the extracted seasonal signals of vegetation indices increased by approximately 0.002–0.004(NDVI)and 0.065–0.298(PRI)on the three crops,and the seasonal signals of vegetation indices became noticeably *** method will contribute to an agricultural monitoring system by identifying the seasonal changes in crop growth and physiological conditions.

关键词： photochemical reflectance index normalized difference vegetation index vegetation remote sensing spectral reflectance sensor

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serial blood concentration of polyethoxylated tallow amine and clinical presentations in acute herbicide poisoning

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World Journal of Emergency Medicine 2022年第4期13卷 305-308页

作者： Jungsoo Park Sun Cheun Kim Youngjoon Jeon Yong Chul Cho Changshin Kang Yeonho You Hong Joon Ahn seung ryu Jihan Lee Wonjoon Jeong Department of Emergency Medicine Chungnam National University HospitalDaejeon 35015South Korea Department of Emergency Medicine College of MedicineChungnam National UniversityDaejeon 35015South Korea Forensic Toxicology Division National Forensic ServiceDaejeon 34054South Korea Department of Emergency Medicine Chungbuk National University HospitalCheongju 28644South Korea

Most commercially available herbicides contain surfactants as co-formulants to increase adhesion and absorption by plant *** amines,one of the most used surfactants,are non-ionic and derived from animal *** represent a class of surfactants with similar structural features,including polyethoxylated tallow amine(POEA).POEA is widely used in glyphosate,glufosinate-containing *** 2015,the European Food Safety Society(EFSA)concluded that POEA was more toxic than glyphosate when tested in glyphosate-based formulations.[1]They also attributed the poisoning following ingestion by humans to the presence of POEA.

关键词： attributed formulation ethoxy

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Design,Fabrication,and Analysis of Flapping and Folding Wing Mechanism for a Robotic Bird

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Journal of Bionic Engineering 2020年第2期17卷 229-240页

作者： seung Wan ryu Jong Gu Lee Hyoun Jin Kim Department of Mechanical&Aerospace Engineering and Automation Systems Research Institute Seoul National UniversitySeoul 08826Republic of Korea

Emulating periodic main wing movement of a bird for generating lift and thrust remains a significant challenge in developing a robotic *** sequences of main wing motion are comprised of flapping,folding,bending,and *** this paper,we concentrate on the flapping and folding motion,and design two wing mechanisms based on a 4-bar linkage structure:one is only for Flapping Motion(FM)and the other is for simultaneous Flapping and Folding Motion(FFM)during a wing *** derive relationships between length and angle of links to analyze kinematic characteristics of the mechanisms and conduct an optimization to select the length parameters of links that allow maximization of the flapping *** run a simulation to confirm the performance of the optimized parameters by examining physical properties,and fabricate two wing mechanisms *** particular,the folding motion is achieved without using an additional *** measurements to investigate a lift profile of each mechanism and their quantitative comparison of the performance of both types confirm the benefits of the folding motion in the perspectives of wing frequency and *** expect that our kinematic formulation,design procedures,and comparative measurement results can help develop a wing mechanism to create a truly biomimetic robotic bird.

关键词： biomimetic robotic bird flapping and folding wing mechanism wing kinematics force measurement

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An Effective Threat Detection Framework for Advanced Persistent Cyberattacks

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Computers, Materials & Continua 2023年第5期75卷 4231-4253页

作者： So-Eun Jeon Sun-Jin Lee Eun-Young Lee Yeon-Ji Lee Jung-Hwa ryu Jung-Hyun Moon Sun-Min Yi Il-Gu Lee Department of Future Convergence Technology Engineering Sungshin Women’s UniversitySeoul02844Korea Department of Convergence security Engineering Sungshin Women’s UniversitySeoul02844Korea

Recently,with the normalization of non-face-to-face online environments in response to the COVID-19 pandemic,the possibility of cyberattacks through endpoints has *** endpoint devices are managed meticulously to prevent cyberattacks and ensure timely responses to potential security *** particular,because telecommuting,telemedicine,and teleeducation are implemented in uncontrolled environments,attackers typically target vulnerable endpoints to acquire administrator rights or steal authentication information,and reports of endpoint attacks have been increasing *** persistent threats(APTs)using various novel variant malicious codes are a form of a sophisticated ***,conventional commercial antivirus and anti-malware systems that use signature-based attack detectionmethods cannot satisfactorily respond to such *** this paper,we propose a method that expands the detection coverage inAPT attack *** this model,an open-source threat detector and log collector are used synergistically to improve threat detection *** the scope of attack log collection through interworking between highly accessible open-source tools can efficiently increase the detection coverage of tactics and techniques used to deal with APT attacks,as defined by MITRE Adversarial Tactics,Techniques,and Common Knowledge(ATT&CK).We implemented an attack environment using an APT attack scenario emulator called Carbanak and analyzed the detection coverage of Google Rapid Response(GRR),an open-source threat detection tool,and Graylog,an open-source log *** proposed method expanded the detection coverage against MITRE ATT&CK by approximately 11%compared with that conventional methods.

关键词： Advanced persistent threat cybersecurity endpoint security MITRE ATT&CK open-source threat detector threat log collector

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Addition of cerium and yttrium to ferritic steel weld metal to improve hydrogen trapping efficiency

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International Journal of Minerals,Metallurgy and Materials 2017年第4期24卷 415-422页

作者： Sung Jin Kim Kang Mook ryu Min-suk Oh Department of Advanced Materials Engineering Sunchon National University Jungang-ro Suncheon 540-742 Republic of Korea POSCO Steel Solution Marketing Division Geidong-Dong Pohang 790-704 Republic of Korea Automotive Components & Materials R&D Group Korea Institute of Industrial Technology 6 Cheomdan-gwagiro 208 beon-gil Gwangju 61012 Republic of Korea

The applicability of Ce and Y as promising candidate elements to form irreversible traps in weld metal was investigated by thermal desorption spectroscopy(TDS) with gas chromatography(GC). The precise nature of the precipitate particles newly formed in the weld metal by the addition of Ce and Y to a certain alloy system was characterized. Moreover,the hydrogen trapping efficiency expressed as the reduction of the diffusible hydrogen in the weld metal was analyzed. The results showed that the addition of Ce and/or Y to this alloy system led to the formation of a mixed type of(Ce,Ti)-based oxide,(Y,Ni)-based carbide,or(Ce,Y,Ti)-based oxide particles. Because of the high activation energy of the mixed type of particles(≥ 150 k J/mol),the trapping efficiency for hydrogen was considered to be sufficiently high to effectively reduce the diffusible hydrogen content.

关键词： hydrogen trapping weld rare earth metals cerium yttrium activation energy

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Br-radical-mediated [3+2] annulation: synthesis of 2-bromomethylsubstituted alkenylcyclopentanes by the reaction of alkenylcyclopropanes with allyl bromides under photo irradiation

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Science China Chemistry 2019年第11期62卷 1525-1528页

作者： Takahide Fukuyama Takashi Kippo Kanako Hamaoka Ilhyong ryu Department of Chemistry Graduate School of Science Osaka Prefecture University

A radical chain addition of allyl bromides 2 to alkenylcyclopropanes 1 resulted in[3+2]annulation to give 2-bromomethylalkenylcyclopentanes 3 in good yields(16 examples).In this reaction,two kinetically fast radical reactions,cyclopropylcarbinyl radical-ring-opening and 5-exo-radical cyclization,preceded theβ-fragmentation of a bromine radical to make the formal cycloaddition possible.

关键词： [3+2]annulation bromine radical alkenylcyclopropanes alkenylcyclopentanes photo irradiation

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Practical considerations of Si-based anodes for lithiumion battery applications

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Nano Research 2017年第12期10卷 3970-4002页

作者： Jaegeon ryu Dongki Hong Hyun-Wook Lee Soojin Park Department of Energy Engineering School of Energy and Chemical Engineering Ulsan National Institute of Science and Technology (UNIST) Ulsan 44919 Republic of Korea

Using Si-based anodes in Li-ion batteries is one of the most feasible approaches to achieve high energy densities despite their disadvantages, such as low conductivity and massive volume expansion, which cause unstable solid electrolyte interphase layers with mechanical failure. The forefront in research and development to address the above challenges suggests the possibility of fully commercially viable cells using various structural and interfacial modifications. In particular, we present a discussion of each dimension of Si-based anodes in multiple controlled systems, including plain, hollow, porous, and uniquely engineered structures, which are further evaluated based on their anode performances, such as initial reversibility, capacity retention for extended cycles with its efficiency, degree of volume expansion tolerance, and rate capabilities, by several practical standards in half cells. With these practical considerations, multi-dimensional structures with uniform size distributions （micrometers, on average） are strongly desired to satisfy the rigorous requirements for widespread applications. Furthermore, we closely examined several full cells composed of Si-based multicomponent anodes coupled with suitable cathodes based on practical standards to propose future research directions for Si-based anodes to keep pace with the rapidly changing market demands for diverse energy storage systems.

关键词： silicon anode dimensional control full celllithium-ion batteries practicality

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Superior mechanical properties and strengthening mechanisms of lightweight AlxCrNbVMo refractory high-entropy alloys(x=0,0.5,1.0)fabricated by the powder metallurgy process

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Journal of Materials Science & Technology 2021年第10期69卷 32-41页

作者： Byungchul Kang Taeyeong Kong Ho Jin ryu Soon Hyung Hong Department of Material Science and Engineering Korea Advanced Institute of Science and Technology(KAIST)291 Daehak-roYuseong-guDaejeon 34141Republic of Korea Department of Nuclear and Quantum Engineering Korea Advanced Institute of Science and Technology(KAIST)291 Daehak-roYuseong-guDaejeon 34141Republic of Korea

Light and strong AlxCrNbVMo(x=0,0.5,and 1.0)refractory high-entropy alloys(RHEAs)were designed and fabricated via a the powder metallurgical *** microstructure of the AlxCrNbVMo alloys consisted of a single BCC crystalline structure with a sub-micron grain size of 2-3μm,and small amounts(segregation or micropores was achieved via high-energy ball milling and spark-plasma *** alloys exhibited superior mechanical properties at 25 and 1000℃compared to those of other ***,CrNbVMo alloy showed a yield strength of 2743 MPa at room ***,the yield strength of the CrNbVMo alloy at 1000℃was 1513 *** specific yield strength of the CrNbVMo alloy was increased by 27%and 87%at 25 and 1000℃,respectively,compared to the AlMo_(0.5) NbTa_(0.5)TiZr RHEA,which exhibited so far the highest specific yield strength among the cast *** addition of Al to CrNbVMo alloy was advantageous in reducing its reduce density to below 8.0 g/cm^(3),while the elastic modulus decreased due to the much lower elastic modulus of Al compared to that of the CrNbVMo *** analysis of the strengthening contributions,showed that the solid solution strengthening,arising from a large misfit effect due to the size and modulus,and the high shear modulus of matrix,was revealed to predominant strengthening mechanism,accounting for over 50%of the yield strength of the AlxCrNbVMo RHEAs.

关键词： High-entropy alloy Powder metallurgy Refractory Strengthening mechanisms Oxide dispersoids

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Improvement of photovoltaic properties of benzo[1,2-b:4,5-b′]difuran-conjugated polymer by side-chain modification

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ChemPhysMater 2023年第3期2卷 225-230页

作者： Yun Li Guangkai Lu Linglong Ye Hwa Sook ryu Yunhao Cai Han Young Woo Yan Li Yanming Sun School of Chemistry Beihang UniversityBeijing 100191China Department of Chemistry College of ScienceKorea UniversitySeoul 136-713Republic of Korea

The development of polymer solar cells(PSCs)for the donor materials based on benzo[1,2-b:4,5-b′]dithiophene(BDT)has significantly boosted the power conversion efficiency(PCE).However,the PCE of polymer donor materials for benzo[1,2-b:4,5-b′]difuran(BDF)-based lags far behind that of their BDT *** further explore efficient copolymers based on BDF units,a two-dimensional(2D)side-chain strategy was proposed to investigate the atom-changing effects on the copolymer donors for the properties of electron and *** this study,we designed and synthesized three new BDF-based copolymer donor materials,named PBDF-C,PBDF-O,and *** to the balanced charge transport and favorable phase separation of PBDF-S:Y6,a high PCE of 13.4%,a short-circuit current(J sc)of 25.48 mA cm−2,an open-circuit voltage(V oc)of 0.721 V,and a fill factor(FF)of 72.6%was *** research demonstrates that the BDF building block has great potential for constructing conjugated copolymer donors for high-performance PSCs and that 2D side-chain modification is a facile approach for designing high-performance BDF-based copolymer materials.

关键词： Polymer solar cells Benzodifuran Side-chain modification Polymer donor Efficiency

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Estimation of Organic Matter Content in Coastal Soil Using Reflectance Spectroscopy

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Pedosphere 2016年第1期26卷 130-136页

作者： ZHENG Guanghui Dongryeol ryu JIAO Caixia HONG Changqiao School of Geography and Remote sensing Nanjing University of Information Science & Technology Department of Infrastructure Engineering University of Melbourne

Rapid determination of soil organic matter(SOM) using regression models based on soil reflectance spectral data serves an important function in precision agriculture. "Deviation of arch"(DOA)-based regression and partial least squares regression(PLSR)are two modeling approaches to predict ***,few studies have explored the accuracy of the DOA-based regression and PLSR ***,the DOA-based regression and PLSR were applied to the visible near-infrared(VNIR) spectra to estimate SOM content in the case of various dataset divisions.A two-fold cross-validation scheme was adopted and repeated 10 000 times for rigorous evaluation of the DOA-based models in comparison with the widely used PLSR *** samples were collected for SOM analysis in the coastal area of northern Jiangsu Province,*** results indicated that both modelling methods provided reasonable estimation of SOM,with PLSR outperforming DOA-based regression in ***,the performance of PLSR for the validation dataset decreased more *** the four DOA-based regression models,a linear model provided the best estimation of SOM and a cutoff of SOM content(19.76 g kg^(-1)),and the performance for calibration and validation datasets was *** the SOM content exceeded 19.76 g kg^(-1),SOM became more effective in masking the spectral features of other soil properties to a certain *** work confirmed that reflectance spectroscopy combined with PLSR could serve as a non-destructive and cost-efficient way for rapid determination of SOM when hyperspectral data were *** DOA-based model,which requires only 3 bands in the visible spectra,also provided SOM estimation with acceptable accuracy.

关键词：土壤有机质含量滨海土壤反射光谱偏最小二乘回归回归模型高光谱数据估算精度估计

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