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Distribution of Chancelloriids in a Middle Cambrian Carbonate Platform Deposit, Taebaek Group, Korea

Acta Geologica Sinica(English Edition) 2016年第3期90卷 783-795页

作者： HONG Jongsun CHOH suk-Joo lee Dong-Jin Department of Earth and Environmental Sciences Korea University Department of Earth and Environmental Sciences Andong National University

The onset of the Cambrian witnessed the diversification of ＂small shelly fossils （SSF）＂, which affected carbonate depositional system. One of the problematic SSF, chancelloriids, are common components of the early to middle Cambrian carbonate and shale, and their contributions toward Cambrian carbonates are not yet fully understood. This study assesses distribution patterns of chancelloriid sclerites in the Cambrian Series 3 Daegi Formation based on microfacies analysis and discusses their sedimentologic implications. In the lower part of the formation, partially articulated chancelloriid sclerites occur mainly in bioclastic packstone and grainstone facies, with isolated sclerite rays in nodular packstone to grainstone facies. In the middle part of the formation, chancelloriid fragments occur only sporadically in bioclastic wackestone to packstone, bioclastic grainstone and oolitic packstone to grainstone facies, whereas boundstone facies are nearly devoid of their fragments. There are no chancelloriid fragments in the upper part of the formation, which consists of oolitic packstone to grainstone facies. Chancelloriids are interpreted to have primarily occupied platform margin shoal environments, shedding their sclerites to surrounding areas, and thus contributed as sediment producers. The distribution of Daegi chancelloriid sclerites is similar to other Cambrian examples, with the exception of common chancelloriids in Cambrian Series 2 reefs and their apparent near absence in the Daegi and other Cambrian Series 3 reefs. This disparity resulted from changes in the ecologic niche of chancelloriids after the end-Cambrian Series 2 reef crisis, coupled with an overall decline of chancelloriids in the middle Cambrian.

关键词： Cambrian Series 3 chancelloriid shoal carbonate platform reef

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Synthesis of a Rod-rod Diblock Copolymer, Poly (3-hexylthiophene)-block-poly(furfuryl isocyanate), through the Anionic Polymerization with an Oxyanionic Macroinitiator

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Chinese Journal of Polymer Science 2019年第9期37卷 866-874页

作者： Chang-Geun Chae Joonkeun Min In-Gyu Bak Jae-suk lee School of Materials Science and Engineering Gwangju Institute of Science and Technology (GIST)

A rod-rod diblock copolymer (diBCP), poly(3-hexylthiophene)-block-poly(furfuryl isocyanate)(P3HT-b-PFIC), was synthesized through the anionic polymerization with an oxyanionic macroinitiator of P3HT. The properties of the diBCP (molecular weight, dispersity, composition, thermal stability, UV-visible absorption, and thin film morphology) were determined by various analytical methods. P3HT-b-PFIC was blended with C60 in a toluene solution to prepare a thin film of binary electron donor/acceptor system. Such blending enabled partial conjugation of the two components by the Diels-Alder reaction between furan and C60 at 60℃ for 3 h;the mixture was then spin-cast as a thin film, and annealed at 250℃ for 24 h. Tapping-mode atomic force microscopy (AFM) revealed that P3HT and C60 domains had nanoscale interfaces without a large phase segregation. This result indicated that the microphase separation of C60-functionalized P3HT-b-PFIC preserved even at high temperature provided free C60 molecules with channels to diffuse on the sides of P3HT domain, thus preventing the macroscopic crystallization of free C60 through the interfacial stabilization.

关键词： Rod-rod diblock copolymer Poly(3-hexylthiophene)-block-poly(furfuryl isocyanate) C60 Diels-Alder reaction Nanoscale interfaces

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Self-motivated,thermally oxidized hematite nanoflake photoanodes:Effects of pre-polishing and ZrO_(2) passivation layer

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Journal of Energy Chemistry 2022年第2期31卷 415-423页

作者： Love Kumar Dhandole Hyun Hwi lee Weon-Sik Chae Jum suk Jang Jae Sung lee Department of Energy Engineering School of Energy and Chemical EngineeringUlsan National Institute of Science and Technology(UNIST)Ulsan 44919Republic of Korea Division of Biotechnology College of Environmental and Bioresource SciencesChonbuk National UniversityIksan 54596Republic of Korea Pohang Accelerator Laboratory Pohang University of Science and Technology(POSTECH)Pohang 37673Republic of Korea Daegu Center Korea Basic Science InstituteDaegu 41566Republic of Korea

High-temperature thermal oxidation of an Fe foil produces a high-quality,crystalline hematite nanoflake suitable as a photoanode for the photoelectrochemical(PEC)water *** pre-polishing of the foil surface has a profound effect in the formation of a vertically-aligned nanoflakes of hematite phase with extended(110)planes by removing the loosely-bonded oxide *** the surface of the photoanode is modified with a ZrO_(2) passivation layer and a cobalt phosphate co-catalyst,the charge recombination at the photoanode-electrolyte interface is greatly suppressed to improve its overall PEC *** a result,the photocurrent density at 1.10 VRHE under 1 sun condition is enhanced from 0.22 mA cm^(-2) for an unmodified photoanode to 0.59 mA cm^(-2) for the fully modified photoanode,and the photocurrent onset potential is shifted cathodically by 400 ***,the photoanode demonstrates outstanding stability by showing steady production of H_(2) and O_(2) gases in the stoichiometric ratio of 2:1 in a continuous PEC operation for 10 h.

关键词： Fe foil Thermal oxidation Nanoflakes Photoelectrochemical water splitting Surface modifications

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Modeling and Hardware-in-the-Loop System Realization of Electric Machine Drives-A Review

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CES Transactions on Electrical Machines and Systems 2021年第3期5卷 194-201页

作者： Jae suk lee Gilsu Choi the Jeonbuk National University JeonjuJeonbukKorea Inha University IncheonKorea

This paper presents a state-of-the-art review in modeling approach of hardware in the loop simulation(HILS)realization of electric machine drives using commercial real time *** implementation using digital signal processors(DSPs)and field programmable gate array(FPGA)for electric machine drives has been investigated but those methods have drawbacks such as complexity in development and *** various HILS implementation approaches,more efficient development and verification for electric machine drives can be achieved through use of commercial real time *** well as implementation of the HILS,accurate modeling of a control target system plays an important ***,modeling trend in electric machine drives for HILS implementation is needed to be *** paper provides a background of HILS and commercially available real time machines and characteristics of each real time machine are ***,recent trends and progress of permanent magnet synchronous machines(PMSMs)modeling are presented for providing more accurate HILS implementation approaches in this paper.

关键词： Hardware-in-the-loop machine modeling permanent magnet synchronous machine(PMSM) model based design

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Absorption-Dominant mmWave EMI Shielding Films with Ultralow Reflection using Ferromagnetic Resonance Frequency Tunable M-Type Ferrites

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Nano-Micro Letters 2023年第6期15卷 1-23页

作者： Horim lee Seung Han Ryu suk Jin Kwon Jae Ryung Choi Sang‑bok lee Byeongjin Park Composites Research Division Korea Institute of Materials Science797 ChangwondaeroSeongsan‑GuChangwonGyeongsangnam‑Do 51508Republic of Korea

Although there is a high demand for absorption-dominant electromagnetic interference(EMI) shielding materials for 5G millimeter-wave(mmWave) frequencies, most current shielding materials are based on reflection-dominant conductive materials. While there are few absorption-dominant shielding materials proposed with magnetic materials, their working frequencies are usually limited to under 30 GHz. In this study, a novel multi-band absorption-dominant EMI shielding film with M-type strontium ferrites and a conductive grid is proposed. This film shows ultralow EMI reflection of less than 5% in multiple mmWave frequency bands with sub-millimeter thicknesses, while shielding more than 99.9% of EMI. The ultralow reflection frequency bands are controllable by tuning the ferromagnetic resonance frequency of M-type strontium ferrites and composite layer geometries. Two examples of shielding films with ultralow reflection frequencies, one for 39 and 52 GHz 5G telecommunication bands and the other for 60 and 77 GHz autonomous radar bands, are presented. The remarkably low reflectance and thinness of the proposed films provide an important advancement toward the commercialization of EMI shielding materials for 5G mmWave applications.

关键词： 5G communication MmWave EMI shielding M-type ferrites

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Radiolarians from the Pohang Basin,Southeast Korea and Paleoceanographic Implications

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Acta Geologica Sinica(English Edition) 2012年第6期86卷 1426-1433页

作者： Young-suk BAK Jong-Deock lee Hyesu YUN Jinyong OH Seong-Joo lee Kyungpook National University Chonbuk National University Chungnam National University

We identified a total of 101 species and two subspecies of radiolarians belonging to 56 genera from 95 samples collected from the Hagjeon and Duho Formations in the Pohang Basin of the southeastern Korean Peninsula. On the basis of the biostratigraphic range of Cyrtocapsella cornuta and Theocorys redondoensis, the depositional period of the upper Hagjeon and lowest Duho Formations was determined to be early to late Middle Miocene. The occurrence of deep-dwelling radiolarians indicates that the paleobathymetry seems to become gradually progressing toward an upper bathyal environment in the middle part of the Hagjeon Formation. However, we prefer to accept another interpretation for the occurrence of deep-sea indicators in the Hagjeon and the lowest part of the Duho Formations, and consider the presence of a region of upwelling cold water that might have simulated a deep-water environment in relatively shallow water. This interpretation is based on the present upwelling of a cold-water mass off the southeast coast of Korea, the occurrence of upwelling microfossils from the Pohang Basin, and the effect of the closing of the Korea Strait approximately 15 Ma. We also considered that the uppermost part of the studied section represents a shallow-water environment.

关键词： radiolarian depositional environment upweHing Pohang Basin

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Improving hydroxyapatite coating ability on biodegradable metal through laser-induced hydrothermal coating in liquid precursor:Application in orthopedic implants

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Bioactive Materials 2023年第7期25卷 796-806页

作者： Jaeho Park Seung-Hoon Um Youngmin Seo Jaehong lee Yu-Chan Kim Myoung-Ryul Ok suk-Won Hwang Jeong-Yun Sun hyung-Seop Han Hojeong Jeon Biomaterials Research Center Biomedical Research DivisionKorea Institute of Science and Technology(KIST)Seoul02792South Korea Department of Materials Science and Engineering Seoul National University(SNU)Seoul08826South Korea Division of Biomedical Science and Technology KIST SchoolKorea University of Science and TechnologySeoul02792South Korea KU-KIST Graduate School of Converging Science and Technology Korea UniversitySeoul02841South Korea

During the past decade,there has been extensive research toward the possibility of exploring magnesium and its alloys as biocompatible and biodegradable materials for implantable *** practical medical application,however,has been limited to specific areas owing to rapid corrosion in the initial stage and the consequent *** coatings can significantly reduce the initial corrosion of Mg alloys,and several studies have been carried out to improve the adhesion strength of the coating to the surfaces of the *** composition of hydroxyapatite(HAp)is very similar to that of bone tissue;it is one of the most commonly used coating materials for bone-related implants owing to favorable osseointegration *** this study,HAp was coated on Mg using nanosecond laser coating,combining the advantages of chemical and physical *** heat generated in the liquid precursor by the laser improved the adhesion of the coating through the precipitation and growth of HAp at the localized nanosecond laser focal area and increased the corrosion resistance and cell adhesion of *** physical,crystallographic,and chemical bondings were analyzed to explore the mechanism through which the surface adhesion between Mg and the HAp coating layer *** applicability of the coating to Mg screws used for clinical devices and improvement in its corrosion property were *** liquid environment-based laser surface coating technique offers a simple and quick process that does not require any chemical ligands,and therefore,overcomes a potential obstacle in its clinical use.

关键词： Biodegradable metal HAp coating Nanosecond laser Photothermal synthesis Soret effect(thermophoresis)

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Effects of casting speed on microstructure and segregation of electromagnetically stirred Aluminum alloy in continuous casting process

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Rare Metals 2006年第z2期25卷 118-123页

作者： lee Dock-Young KANG suk-Won CHO Duck-Ho KIM Ki-Bae Division of Materials Korea Institute of Science and Technology P.O. Box 131 Cheongryang Seoul 130-650 Korea Department of Applied Materials Engineering Hanbat National University Daejeon 305-719 Korea

Recently, a semi-solid metal processing has been acknowledged as a cost-effective technique to be able to manufacture high quality product for the transportation industry. In this study a hypo-eutectic Al alloy was fabricated by means of an electromagnetic stirrer in continuous casting process and the microstructural change during solidification due to a fluid flow by electromagnetic stirring was examined. Due to the forced fluid flow during solidification a dendritic phase of primary α phase of Al alloy was turned into a globular phase, which can make the Al alloy get a thixotropic behavior in the semi-solid region. In order to establish the quantitative relationship between microstructure and the process parameters, the morphology shape, a silicon distribution and a size of primary α phase were observed according to casting speed in continuous casting machine. The primary α phase was turned into the degenerate dendrites approaching a spherical configuration with increasing casting speed. The fine-grained and equiaxed microstructure appeared at higher casting speed. A segregation behavior of Si element was declined with increasing casting speed and a very uniform distribution of Si element was observed on the billet at a casting speed of 600 mm·min-1. A thickness of the solidifying shell of the billet was shortened with increasing the casting speed.

关键词： semi-solid slurry electromagnetic stirring casting speed segregation Al alloy

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Lithofacies modeling by multipoint statistics and economic evaluation by NPV volume for the early Cretaceous Wabiskaw Member in Athabasca oilsands area, Canada

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Geoscience Frontiers 2018年第2期9卷 441-451页

作者： Kwang Hyun Kim Kyungbook lee Hyun suk lee Chul Woo Rhee Hyun Don Shin Petroleum and Marine Research Division Korea Institute of Geoscience and Mineral Resources Department of Earth and Environmental Sciences Chungbuk National University Department of Energy Resources Engineering Inha University

The static modeling and dynamic simulation are essential and critical processes in petroleum exploration and development. In this study, lithofacies models for Wabiskaw Member in Athabasca, Canada are generated by multipoint statistics(MPS) and then compared with the models built by sequential indicator simulation(SIS). Three training images(Tls) are selected from modern depositional environments;the Orinoco River Delta estuary, Cobequid bay-Salmon River estuary, and Danube River delta environment. In order to validate lithofacies models, average and variance of similarity in lithofacies are calculated through random and zonal blind-well *** random six-blind-well test, similarity average of MPS models is higher than that of SIS model. The Salmon MPS model closely resembles facies pattern of Wabiskaw Member in subsurface. Zonal blind-well tests show that successful lithofacies modeling for transitional depositional setting requires additional or proper zonation information on horizontal variation, vertical proportion, and secondary *** Wabiskaw Member is frontier oilsands lease, it is impossible to evaluate the economics from production data or dynamic simulation. In this study, a dynamic steam assisted gravity drainage(SAGD)performance indicator(SPIDER) on the basis of reservoir characteristics is calculated to build 3 D reservoir model for the evaluation of the SAGD feasibility in Wabiskaw Member. SPIDER depends on reservoir properties, economic limit of steam-oil ratio, and bitumen price. Reservoir properties like porosity,permeability, and water saturation are measured from 13 cores and calculated from 201 well-logs. Three dimensional volumes of reservoir properties are constructed mostly based on relationships among properties. Finally, net present value(NPV) volume can be built by equation relating NPV and SPIDER. The economic area exceeding criterion of US$ 10,000 is identified, and the ranges of reservoir properties are estimated. NPV-volume-generati

关键词： Oilsands Multipoint statistics (MPS) Reservoir static modeling Economic evaluation Net present value (NPV) SAGD, and SPIDER

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Septic thrombophlebitis of the porto-mesenteric veins as a complication of acute appendicitis

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World Journal of Gastroenterology 2008年第28期14卷 4580-4582页

作者： Yeon Soo Chang Sun Young Min Sun hyung Joo suk- Hwan lee Department of Surgery Kyung Hee University College of MedicineSeoul 134-727South Korea

Pylephlebitis, a rare complication of acute appendicitis, is defined as thrombophlebitis of the portal venous system. Pylephlebitis usually occurs due to secondary infection in the region drained into the portal system. We report a case of pylephlebitis caused by acute appendicitis. The patient was transferred from a private clinic 1 wk after appendectomy with the chief complaints of high fever and abdominal pain. He was diagnosed with pylephlebitis of the portal vein and superior mesenteric vein by CT-scan. The patient was treated with antibiotics and anticoagulation therapy, and discharged on the 25th day and follow-up CT scan showed a cavernous transformation of portal thrombosis.

关键词： Acute appendicitis Pylephlebitis Antibiotics Anti-coagulation therapy

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