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Effects of ozonation and coagulation on effluent organic matter characteristics and ultrafiltration membrane fouling

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Journal of Environmental Sciences 2014年第6期26卷 1325-1331页

作者： Kwon Jeong dae-Sung lee Do-Gun Kim seok-Oh Ko Department of Civil Engineering Kyung Hee UniversityYongin 446-701 Korea Institute of Construction Technology KUMHO Engineering & ConstructionYongin 449-822 Korea

Effluent organic matter （EfOM） is the major cause of fouling in the low pressure membranes process for wastewater reuse. Coagulation and oxidation of biological wastewater treatment effluent have been applied for the fouling control of microfiltration membranes. However, the change in EfOM structure by pre-treatments has not been clearly identified. The changes of EfOM characteristics induced by coagulation and ozonation were investigated through size exclusion chromatography, UV/Vis spectrophotometry, fluorescence spectrophotometry and titrimetric analysis to identify the mechanisms in the reduction of ultrafiltration （UF） membrane fouling. The results indicated that reduction of flux decline by coagulation was due to modified characteristics of dissolved organic carbon （DOC） content. Total concentration of DOC was not reduced by ozonation. However, the mass fraction of the molecules with molecular weight larger than 5 kDa, fluorescence intensity, aromaticity, highly condensed chromophores, average molecular weight and soluble microbial byproducts decreased greatly after ozonation. These results indicated that EfOM was partially oxidized by ozonation to low molecular weight, highly charged compounds with abundant electron- withdrawing functional groups, which are favourable for alleviating UF membrane flux decline.

关键词： effluent organic matter fouling ultrafiltration oxidation molecular weight distribution acidity

Inhibitory effects of rapamycin on the different stages of hepatic fibrosis

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World Journal of Gastroenterology 2014年第23期20卷 7452-7460页

作者： Yun Jeung Kim Eaum seok lee seok Hyun Kim Heon Young lee Seung Moo Noh dae Young Kang Byung seok lee Department of Internal Medicine Chungnam National University School of MedicineDaejeon 301-721South Korea Department of Surgery Chungnam National University School of MedicineDaejeon 301-721South Korea Department of Pathology Chungnam National University School of MedicineDaejeon 301-721South Korea

AIM: To investigate and compare the inhibitory effects of rapamycin in the different stages of liver fibrosis.

关键词： Liver cirrhosis Sirolimus Transforming growth factor beta Platelet-derived growth factor Ribosomal protein S6 kinases

Lubrication properties of silver-palladium alloy prepared by ion plating method for high temperature stud bolt

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Transactions of Nonferrous Metals Society of China 2011年第A1期21卷 12-16页

作者： Jung-dae KWON Sunghun lee Koo-Hyun lee Jong-Joo RHA Kee-seok NAN Se-Hun KWON Materials Processing Division Korea Institute of Materials Science Changwon Gyeongnam 641-831 Korea National Core Research Center for Hybrid Materials Solution Pusan National University

As a solid lubricant, silver-palladium (Ag-Pd) alloy coating was investigated for the application to high temperature stud bolt. A glue layer nickel (Ni) film was deposited on the surface of the hex bolt sample and then Ag-Pd alloy coating was performed on it using ion plating method. The friction coefficient of Ag-Pd alloy film coated bolt was lower than that of N-5000 oil coated bolt by the result of axial force measurement. The cyclic test of heat treatment was conducted to evaluate the durability of Ag-Pd alloy film coated bolt. In a cycle, sample was assembled into the block using torque wrench, followed by heating and disassembling. It was not successful to disassemble the N-5000 oil coated bolt from the block after only one cycle. However, the Ag-Pd alloy film coated bolt was able to be disassembled softly till 12 cycles.

关键词： solid lubricant silver-palladium alloy ion plating

Porously Reduced 2-Dimensional Bi_(2)O_(2)CO_(3) Petals for Strain-Mediated Electrochemical CO_(2) Reduction to HCOOH

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Energy & Environmental Materials 2024年第1期7卷 215-221页

作者： Won seok Cho dae Myung Hong Wan Jae Dong Tae Hyung lee Chul Jong Yoo Donghwa lee Ho Won Jang Jong-Lam lee Department of Materials Science and Engineering Pohang University of Science and Technology(POSTECH)Pohang Gyungbuk 37673Korea Department of Materials Science and Engineering Research Institute of Advanced Materials Seoul National UniversitySeoul 08826Korea

Here we introduce bismuth-based catalysts for the efficient electrochemical reduction of CO_(2)to formic acid(HCOOH),which are composed of petal-shaped Bi_(2)O_(2)CO_(3)(BOC)that spontaneously formed from Bi thin film in aqueous carbonate solution at room *** the electrochemical reduction process,the BOC petals transform to reduced BOC(R-BOC)consisting of individual BOC and Bi *** mismatch between both domains induces biaxial strain at the *** functional theory calculations suggest that the tensile strain on the Bi domain stabilizes the*OCHO intermediate,reducing the thermodynamic barrier toward CO_(2)conversion to *** with the thermodynamic benefit and the unique nanoporous petal-shaped morphology,R-BOC petals have a superior Faradaic efficiency of 95.9%at-0.8 V_(RHE)for the electrochemical conversion of CO_(2)to *** work demonstrates that the spontaneously formed binary phases with desirable lattice strain can increase the activity of bismuth catalysts to the CO_(2)reduction reaction;such a strategy can be applicable in design of various electrocatalysts.

关键词： bismuth carbon dioxide reduction formic acid heterointerfaces strain

Phantom Maps from a Strong Homology Viewpoint

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Acta Mathematica Sinica,English Series 2006年第3期22卷 711-718页

作者： dae Woong lee Department of Mathematics Chonbuk National University

Let X and Y be connected nilpotent CW-complexes of finite type. In this paper we deal with another complete analysis of a set of phantom maps in terms of strong homology by using the derived functors. We also prove that the set of homotopy classes of maps is independent of the choice of both rational homotopy equivalent classes and completion genera.

关键词： Phantom map Derived limit Strong homology Rational equivalence Profinite completion

On the Same n-Types for the Wedges of the Eilenberg-Maclane Spaces

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Chinese Annals of Mathematics,Series B 2016年第6期37卷 951-962页

作者： dae-Woong lee Department of Mathematics Institute of Pure and Applied Mathematics Chonbuk National University

Given a connected CW-space X, SNT（X） denotes the set of all homotopy types [X＇] such that the Postnikov approximations X（n） and X＇^（n） are homotopy equivalent for all n. The main purpose of this paper is to show that the set of all the same homotopy n- types of the suspension of the wedges of the Eilenberg-MacLane spaces is the one element set consisting of a single homotopy type of itself, i.e., SNT（Σ（K（Z, 2a1） ∨ K（Z, 2a2）∨… ∨ K（Z,2ak））） = ＊ for a1 〈 a2 〈 … 〈 ak, as a far more general conjecture than the original one of the same n-type posed by McGibbon and Moller （in [McGibbon, C. A. and Moller, J. M., On infinite dimensional spaces that are rationally equivalent to a bouquet of spheres, Proceedings of the 1990 Barcelona Conference on Algebraic Topology, Lecture Notes in Math., 1509, 1992, 285-293].）

关键词： Same n-type Aut Basic Whitehead product Samelson product Bott-Samelson theorem Tensor algebra Cartan-Serre theorem Hopf-Thom theorem

AN ANALOGUE OF KüNNETH THEOREM INSTRONG HOMOLOGY

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Acta Mathematica Scientia 2002年第1期22卷 32-40页

作者： dae- Woong lee Department of Mathematics Myungshin University Sunchon Chonnam 540-871 South Korea

After defining the strong tensor product of strong (sub)chain complenes, it is shown that an analogue of the Kunneth theorem holds in strong homology by proving that the kernel (cokernel) of connecting homomorphisms is isomorphic to the direct sum of torsion (tensor) products of strong homology groups. An isomorphism between strong (r-stage) homology groups of inverse systems is also constructed.

关键词： Derived limit strong (r-stage) homology strong tensor product Mittag-Leffler property

ON INVERSES AND ALGEBRAIC LOOPS OF CO-H-SPACES

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Acta Mathematica Scientia 2014年第4期34卷 1193-1211页

作者： dae-Woong lee Department of Mathematics and Institute of Pure and Applied MathematicsChonbuk National University567 Baekje-daeroDeokjin-guJeonju-siJeollabuk-do 561-756Republic of Korea

In this paper we study the properties of homotopy inverses of comultiplications and Mgebraic loops of co-H-spaces based on a wedge of spheres. We also investigate a method to construct new comultiplications out of old ones by using a group action. We are primarily interested in the algebraic loops which have inversive, power-associative and Moufang properties for some comultiplications.

关键词： inverses co-H-spaces comultiplications basic (Whitehead) product Hopf- Hilton invariants algebraic loops inversivity power-associativity Moufang property

A Strategy of Signal Detection for Performance Improvement in Clipping Based OFDM System

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Computers, Materials & Continua 2020年第7期64卷 181-191页

作者： Jae-Hyun Ro Won-seok lee Min-Goo Kang dae-Ki Hong Hyoung-Kyu Song Department of Information and Communication Engineering Sejong UniversitySeoulKorea Department of IT Contents Hanshin UniversityOsan-siKorea Department of System Semiconductor Engineering SangMyung UniversityCheonan-si31066Korea

In this paper,the supervised Deep Neural Network(DNN)based signal detection is analyzed for combating with nonlinear distortions efficiently and improving error performances in clipping based Orthogonal Frequency Division Multiplexing(OFDM)*** of the main disadvantages for the OFDM is the high Peak to Average Power Ratio(PAPR).The clipping is a simple method for the PAPR ***,an effect of the clipping is nonlinear distortion,and estimations for transmitting symbols are difficult despite a Maximum Likelihood(ML)detection at the *** DNN based online signal detection uses the offline learning model where all weights and biases at fully-connected layers are set to overcome nonlinear distortions by using training data ***,this paper introduces the required processes for the online signal detection and offline learning,and compares error performances with the ML detection in the clipping-based OFDM *** simulation results,the DNN based signal detection has better error performance than the conventional ML detection in multi-path fading wireless *** performance improvement is large as the complexity of system is increased such as huge Multiple Input Multiple Output(MIMO)system and high clipping rate.

关键词： Clipping DNN ML nonlinear distortion OFDM