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Journal of Palaeogeography 2023年第4期12卷 624-636页

作者： Se Chan Kim Rye Sun Choe il Nam Kim Chol U Ryong il Kang Institute of Human Evolution and Development History Faculty of HistoryKim Il Sung UniversityTaesong DistrictPyongyangDemocratic People's Republic of Korea

We present a detailed pollen record and interpretations of late Pleistocene climatic change at the Chongphadae Cave Site, Democratic People's Republic of Korea. The mean annual paleotemperature and mean annual paleoprecipitation of the site were calculated using the temperature index and precipitation index based on ecological features and geographical distribution of each taxon. Temperature index and precipitation index range from 8.8℃ to 10.4℃ and from 805.0 mm to 963.1 mm, respectively. Four dates(radiocarbon, uranium series, fission track, and paleomagnetic excursion dating) of the deposit profile investigated yield a range of ~21.3 ka BP to ~117 ka BP, geochronologically corresponding to the late Pleistocene, and extend from the last interglacial highstand through the Last Glacial Maximum. Our results are thus consistent with the climatic shift from interglacial to glacial conditions, provide evidence that the environments of the region, which was reconstructed from the paleoclimatic index, changed from a mild and humid to a cool and dry climate during the late Pleistocene, and suggest trends similar to those of several parts of the Northern Hemisphere which lie in the same latitudinal zone as our study area.

关键词： Chongphadae cave Pollen Climatic change Late Pleistocene Mean annual temperature Mean annual precipitation

Homogenization on solution treatment and its effects on the precipitation-hardening of selective laser melted 17-4PH stainless steel

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Journal of Materials Science & Technology 2023年第35期166卷 47-57页

作者： Sohee An Du-Rim Eo il Sohn Kyunsuk Choi Department of Materials Science and Engineering Yonsei UniversitySeoul03722Republic of Korea Advanced Joining&Additive Manufacturing R&D Department Korea Institute of Industrial Technology(KITECH)529 Seohaean-roSiheung 15014Republic of Korea Department of Industry-University Convergence Hanbat National UniversityYuseongDaejeon34158Republic of Korea

17-4 precipitation-hardened(PH)stainless steel(SS)exhibits high strength and good corrosion resistance via Cu-precipitation *** conventional wrought 17-4PH SS,Cu segregation andε-Cu pre-cipitates are observed in additively manufactured(AM)17-4PH SS owing to the repeated rapid cooling after heating,which characterizes the AM *** this study,solution treatment was conducted under various temperatures(1,000,1,050,1,100,and 1,200℃)and durations(1,2,4,and 8 h)to minimize the negative effects of Cu segregation andε-Cu precipitates on precipitation *** mechanical prop-erties and microstructures of each condition for the Cu precipitation behavior were *** theε-Cu precipitates did not disappear after solution treatment,the average diameter of theε-Cu precipi-tates tended to decrease with increasing solution treatment temperature and ***,solution treatment at a temperature of 1,200℃ for 8 h was the best,resulting in improved strength compared to the conventional solution treatment at 1,050℃.Solution treatment on at least 1,100℃ is effective in AM.

关键词： Selective laser melting Cu segregation Solution treatment 17-4 Precipitation-hardened stainless steel Additive manufacturing

Adsorption properties of polycarboxylate ether-based superplasticizer on cement particles and their resultant dispersion

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Frontiers of Structural and Civil Engineering 2022年第4期16卷 506-514页

作者： Jinyoung YOON Byoung il CHOI Jae Hong KIM Department of Structural Engineering Research Korea Institute of Civil Engineering and Building Technology(KICT)Goyang 10223Republic of Korea System Safety Research Department Korea Shipbuilding and Offshore EngineeringSeongnam 13591Republic of Korea Department of Civil and Environmental Engineering Korea Advanced Institute of Science and TechnologyDaejeon 34141Republic of Korea

The cement dispersion performance of a polycarboxylate(PCE)-based superplasticizer is highly related to their adsorption behaviors as a function of *** study evaluated effects of PCEs on rheological properties of cementitious ***,characteristics of PCEs were characterized via permeation chromatography(GPC)and Fourier-transform infrared spectrometry(FT-IR).The adsorption behavior of single and blended PCEs on cementitious composites was identified using total organic carbon analyzer(TOC).Based on the measurement of PCE adsorption,the changes of rheological properties of cementitious materials as well as the number of dispersed cement particles were characterized using a rheometer and laser spectroscopy,*** experimental results support the systematic mechanism of PCE adsorption,cement dispersion,and the decrease in viscosity of cementitious materials.

关键词： adsorption polycarboxylate superplasticizer rheology dispersion

Optical absorption and photoelectron collection properties of silicon wafers with conical quantum nanocrystals structure

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Nano-Micro Letters 2010年第3期2卷 149-153页

作者： Yuriy Vashpanov Jae-il Jeong Electrical and Computer Engineering Division of Hanyang Institute of Technology Hanyang University

A conical form of nano-sized quantum cluster was formed on the surface of p-type crystalline silicon [111] wafer by anode electrochemical etching in HF-based *** conical surface is highly effective in absorbing sunlight and transporting photoelectrons to semiconductor *** are because each cone has a graded band gap with the energy level in the range from 1.1 to 3 eV which can be considered as consisting of quantum dots in different *** the boron concentration on the surface of each cone gradually decreases from top to bottom,a continuously varying electrical field is created along the cone *** electric field is forcing photoelectrons generated in the cone to move rapidly to the direction perpendicular to wafer *** the drift time of photoelectrons can be less than their recombination time within the thin layer close to the bottom of the cone.

关键词： Silicon Nanocrystals Electrochemical etching Solar cells

Wavelet Estimation in Heteroscedastic Model Under Censored Samples

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Acta Mathematica Sinica,English Series 2007年第12期23卷 2253-2268页

作者： Han Ying LIANG Jong il BAEK Department of Mathematics Tongji University Shanghai 200092 P. R. China School of Mathematics & Informational Statistics and Institute of Basic Natural Science Wonkwang University Ik-San 570-749 South Korea

Consider the heteroscedastic regression model Yi = g（xi）＋ σiei, 1 ≤ i ≤ n, where σi^2 = f（ui）, here （xi, ui） being fixed design points, g and f being unknown functions defined on [0, 1], ei being independent random errors with mean zero. Assuming that Yi are censored randomly and the censored distribution function is known or unknown, we discuss the rates of strong uniformly convergence for wavelet estimators of g and f, respectively. Also, the asymptotic normality for the wavelet estimators of g is investigated.

关键词： censored sample heteroscedastic regression model wavelet estimator strong unform convergence rate asymptotic normality

Identical-video retrieval using the low-peak feature of a video's audio information

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Journal of Zhejiang University-Science C(Computers and Electronics) 2010年第3期11卷 151-159页

作者： Myoung-beom CHUNG il-ju KO Department of Media Soongsil University

The recognition and retrieval of identical videos by combing through entire video files requires a great deal of time and memory space. Therefore, most current video-matching methods analyze only a part of each video's image frame information. All these methods, however, share the critical problem of erroneously categorizing identical videos as different if they have merely been altered in resolution or converted with a different codec. This paper deals instead with an identical-video-retrieval method using the low-peak feature of audio data. The low-peak feature remains relatively stable even with changes in bit-rate or codec. The proposed method showed a search success rate of 93.7% in a video matching experiment. This approach could provide a technique for recognizing identical content on video file share sites.

关键词： Video retrieval Video DNA Audio signal processing Audio feature extraction

Two climate factors in May that affect Korean rainfall in September

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Acta Oceanologica Sinica 2013年第1期32卷 32-47页

作者： CHOI Ki-Seon MOON il-Ju National Typhoon Center Korea Meteorological Administration College of Ocean Science/Ocean and Environment Research Institute Jeju National University

This study revealed a high positive correlation between rainfall in Korea during September and the trade wind （TW）/Arctic Oscillation （AO） index in May that combines two climate factors, low-level TWs and the AO. This correlation was identified on the basis of the difference in the 850 hPa streamline analysis between the positive and negative phases selected using the combined TW/AO index. In May, the spatial pattern of the anomalous pressure systems is similar to that in the positive AO phase. These anomalous pressure sys- tems continue in June to August （JJA） and September, but the overall spatial distribution shifts a little to the south. Particularly in September, a huge anomalous anticyclone centered over the southeast seas of Japan strengthens in most of the western north Pacific region and supplies a large volume of warm and humid air to the region near Korea. This characteristic is confirmed by the facts that during the positive TW/AO phase, the subtropical western north Pacific high （SWNPH） is more developed to the north and that the continu- ous positioning of the upper troposphere jet over Korea from May to September strengthens the anomalous upward flow, bringing warm and humid air to all layers. These factors contribute to increasing September rainfall in Korea during the positive TW/AO phase. Because the SWNPH develops more to the north in the positive phase, tropical cyclones tend to make landfall in Korea frequently, which also plays a positive role in increasing September rainfall in *** above features are also reflected by the differences in average rainfall between the six years that had the highest May Nifio 3.4 indices （El Niflo phase） and the six years that had the lowest May Niflo 3.4 indices （La Nifia phase）.

关键词： anomalous pressure Arctic Oscillation Korea low-level trade wind rainfall tropical cyclone

Sand-polished Kapton film and aluminum as source of electron transfer triboelectric nanogenerator through vertical contact separation mode

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International Journal of Smart and Nano Materials 2020年第1期11卷 38-46页

作者： Ravi Kumar Cheedarala Jung il Song Research Institute of Mechatronics Department of Mechanical EngineeringChangwon National UniversityUichang-guChangwon CityS.Korea

Contact electrification is a direct triboelectrification method for producing current through charge transfer when two different differentiated materials have brought into *** the first time,we developed a simple triboelectric nanogenerator(TENG)where the electronic charges were realized through contact separation mode between sand-polished Kapton(SPK)and Al ***,we demonstrated the energetic interfacial contact between these surfaces and observed satisfactory output *** novel SPK-TENG produced 40 V and 2.8μA,of open-circuit voltages(V_(oc))and short-circuit currents(Isc)at 4 Hz,***,the SPK-TENG was dramatically increased up the performance of TENG,up to 40% of V_(oc) and 42% of I_(sc),with respect to the Kapton film because the mobility of electrons is very high on the device surface compared to the other pristine Kapton *** fabricated SPK-TENGs were good candidates for satisfying the need for alternative contact separation mode TENGs.

关键词： Kapton contactelectrification K-Al TENG SPK-Al TENGs electron transfer mechanism

Hepatic stellate cells and innate immunity in alcoholic liver disease

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World Journal of Gastroenterology 2011年第20期17卷 2543-2551页

作者： Yang-Gun Suh Won-il Jeong Graduate School of Medical Science and Engineering Korea Advanced Institute of Science and Technology

Constant alcohol consumption is a major cause of chronic liver disease, and there has been a growing concern regarding the increased mortality rates worldwide. Alcoholic liver diseases (ALDs) range from mild to more severe conditions, such as steatosis, steatohepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma. The liver is enriched with innate immune cells (e.g. natural killer cells and Kupffer cells) and hepatic stellate cells (HSCs), and interestingly, emerging evidence suggests that innate immunity contributes to the development of ALDs (e.g. steatohepatitis and liver fibrosis). Indeed, HSCs play a crucial role in alcoholic steatosis via production of endocannabinoid and retinol metabolites. This review describes the roles of the innate immunity and HSCs in the pathogenesis of ALDs, and suggests therapeutic targets and strategies to assist in the reduction of ALD.

关键词： Alcoholic liver disease Hepatic stellate cell Natural killer cell Kupffer cell Endocannabinoid Ste-atosis Steatohepatitis Fibrosis

Assessment of Reusing Ferrochrome Slag Wastes in Mortar as SCMs

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Journal of Wuhan University of Technology(Materials Science) 2020年第6期35卷 1043-1052页

作者： IŞil Sanrı Karapınar HASAN Biricik Faculty of Engineering and Natural Sciences Department of Civil EngineeringMaltepe University34857IstanbulTurkey

The demand for alternative cementitious materials is on the rise,as the cement causes huge energy consumption and produces greenhouse gas ***,there is economic potential for the construction industry to reuse wastes as supplementary building *** purpose of this study is to evaluate the potential of utilizing ferrochrome slag wastes in mortar as supplementary cementitious materials (SCMs),thereby achieving this double-sided ***,the mechanical and physical properties of ferrochrome slag wastes were investigated to be used as admixtures in concrete *** different cement mortar specimens were prepared by replacing cement with ferrochrome slag in ratios of 0,30%,and 60% by mass and flexural and compressive strengths of the specimens were determined at the ages of 7,28,56,90,and 180 ***,the effects of the ferrochrome slag replacement ratio on workability,setting time and volume expansion were *** electron microscopy (SEM) and X-ray diffraction (XRD) were also investigated to study the microstructural properties of the specimens containing ferrochrome *** on the results,it is concluded that ferrochrome slag wastes have pozzolanic activity,therefore reusing them as SCMs in the cement and concrete industry is convenient.

关键词： recycling reuse of materials ferrochrome slags pozzolanic activity physical and mechanical properties concrete technology