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Solid-state phase transformations toward a metal-organic framework of 7-connected Zn_(4)0 secondary building units

Nano Research 2021年第2期14卷 411-416页

作者： jaehui Kim Junsu Ha jae Hwa Lee Hoi Ri moon Department of Chemistry Ulsan National Institute of Science and Technology(UNIST) Ulsan 44919Republic of Korea

In the development of metal-organic frameworks(MOFs),secondary building units(SBUs)have been utilized as molecular modules for the construction of nanoporous materials with robust *** solvothermal synthetic conditions,dynamic changes in the metal coordination environments and ligand coordination modes of SBUs determine the resultant product ***,MOF phases with new topologies can also be achieved by post-synthetic treatment of as-synthesized MOFs via the introduction of acidic or basic moieties that cause the simultaneous cleavage/reformation of coordination bonds in the solid *** this sense,we studied the solid-state transformation of two ndc-based Zn-MOFs(ndc=1,4-naphthalene dicarboxylate)with different SBUs but the same pcu topology to another MOF with sev *** of the chosen MOFs with pcu nets is[Zn_(2)(ndc)_(2)(bpy)]_(n)(bpy=4,4,-bipyridine),(6C_(bpy)-MOF)consisting of a 6-connected pillared-paddlewheel SBU,and the other is IRMOF-7 composed of 6-connected Zn40(C 00)6 SBUs and *** post-structural modification,these pcu MOFs were converted into the same MOF with sev topology constructed from the uncommon 7-connected Zri_(4)O(COO)_(7)SBU(7C-MOF).The appropriate post-synthetic conditions for the transformation of each SBUs were systematically *** addition,the effect of the pillar molecules in the pillared-paddlewheel MOFs on the topology conversion was studied in terms of the linker basicity,which determines the inertness during the solid-state phase *** post-synthetic modification approach is expected to expand the available methods for designing and synthesizing MOFs with controlled topologies.

关键词： metal-organic framework secondary building units solid-state transform ation linker basicity ligand addition reaction

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Multi-faceted small molecule for Alzheimer’s disease

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Neural Regeneration Research 2023年第10期18卷 2198-2199页

作者： Min Hee Park Hee Kyung Jin jae-sung bae KNU Alzheimer’s Disease Research Institute Department of PhysiologySchool of MedicineKyungpook National UniversityDaeguSouth Korea KNU Alzheimer’s Disease Research Institute Department of Laboratory Animal MedicineCollege of Veterinary MedicineKyungpook National UniversityDaeguSouth Korea

The main pathologies of Alzheimer’s disease(AD)are the accumulation of amyloid-B(AB)and tau ta ngles,and these two fundamental pathologies accompany the va rious neuropathological features,such as neuroinfla mmation,... 详细信息

关键词： Alzheimer tau amyloid

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Adsorption and photocatalytic degradation of bisphenol A using TiO2 and its separation by submerged hollowfiber ultrafiltration membrane

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Journal of Environmental Sciences 2006年第1期18卷 193-200页

作者： jae-Wook Lee Tae-Ouk Kwon Ramesh Thiruvenkatachari Il-Shik moon Department of Chemistry Engineer Seonam University Namwon 590-711 Korea Department of Chemistry Engineer Sunchon National University Suncheon 540-742 Korea

This study evaluates the adsorption ability ofbisphenol A（BPA） on titanium dioxide（TiO2） and its effect on the photocatalysis by advanced oxidation process using UV radiation and TiO2 photocatalyst. Degradation of BPA was also evaluated for the system without adsorption prior to photocatalytic reaction. The separation of TiO2 from BPA solution treated by pilot-scale photocatalytic reactor （capacity 0.16 m^3） was studied using submerged ultrafiltration （UF） membrane. It was found that although adsorption capacity of BPA was not high, adsorption played an important role in improving the efficiency ofphotocatalysis. On the other hand, during the separation of TiO2 particles from aqueous suspension, the permeate flux of the membrane was strongly affected by transmembrane pressure and TiO2 dose. The permeate turbidity was decreased below 1 NTU.

关键词： bisphenol A TiO2 adsorption membrane photocatalysis

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Origin of superior low-cycle fatigue resistance of an interstitial metastable high-entropy alloy

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Journal of Materials Science & Technology 2022年第20期115卷 115-128页

作者： Seyed Amir Arsalan Shams jae Wung bae jae Nam Kim Hyoung Seop Kim Taekyung Lee Chong Soo Lee Graduate Institute of Ferrous Technology Pohang University of Science and TechnologyPohang 37673Republic of Korea Department of Materials Science and Engineering Pohang University of Science and TechnologyPohang 37673Republic of Korea School of Mechanical Engineering Pusan National UniversityBusan 46241Republic of Korea

In this study, the deformation behaviors and related microstructural evolutions were investigated in either monotonic or cyclic deformation modes in an interstitial metastable high-entropy alloy. These investigations aimed to reveal the mechanisms underlying the superior low-cycle fatigue(LCF) life of this alloy.A thermomechanical process was applied to induce fine-grained(FG) and coarse-grained(CG) microstructures in Fe–30Mn–10Co–10Cr–0.4C(atomic percentage) alloy. Their superior combination of strength and ductility was attributed to the appearance of deformation-induced ε-martensite and the presence of carbon. The CG alloy showed a greater volume fraction of ε-martensite than the FG alloy in the monotonic deformation mode, and vice versa in the cyclic mode. Such a disparity was interpreted in light of the back-stress effect of the relaxed γ-grain boundaries in the latter mode. Meanwhile, the γ-to-ε phase transformation under cyclic loading at low strain amplitudes(0.4%) barely led to an improved fatigue life as compared with that at higher strain amplitudes(≥ 0.55%). The high reversibility of partial dislocation motions under cyclic loading and delaying the formation of dislocation cells through the martensitic transformation could explain why the alloys investigated in this study exhibited a superior LCF life compared with high-entropy alloys reported in previous studies.

关键词： High-entropy alloy Transformation-induced plasticity Monotonic deformation Cyclic deformation Low-cycle fatigue Stacking faults

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Quantitative analysis of mechanical properties associated with aging treatment and microstructure in Mg-Al-Zn alloys through machine learning

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Journal of Materials Science & Technology 2022年第12期107卷 52-63页

作者： Joung Sik Suh Byeong-Chan Suh Sang Eun Lee Jun Ho bae Byoung Gi moon Advanced Metals Division Korea Institute of Materials ScienceChangwon 51508Republic of Korea

The present study proposes a methodology for predicting the mechanical properties of AZ61 and AZ91alloys associated with microstructure,texture and aging parameters and estimating predictor *** this,we investigate quantitative correlations between microstructure,texture and mechanical properties of aged AZ61 and AZ91 rods through machine *** regression analysis focuses on the precipitation behavior of Mg17Al12as the main second phase of Mg-Al-Zn alloys with respect to aging *** simplify data generation,only SEM images were used to quantify the features of discontinuous and continuous *** overcome the lack of data and make the most of the measured data,we devised a method to extend the existing dataset by a factor of 9 using the mean and standard deviation of the measured *** neural networks predicted tensile and compressive yield strengths and resultant yield asymmetry with a high accuracy of over 98%using 11 predictors for a total of *** tree learning quantitatively assessed the importance of predictors in determining the mechanical properties of aged AZ61 and AZ91 rods.

关键词： Magnesium alloy Aging treatment Microstructure Mechanical properties Machine learning

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EXPERIMENTAL ESTIMATION OF A SCALING EXPONENT FOR TIP VORTEX CAVITATION VIA ITS INCEPTION TEST IN FULL-AND MODEL-SHIP

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Journal of Hydrodynamics 2012年第5期24卷 658-667页

作者： LEE Jeung-Hoon JUNG jae-Kwon LEE Kyung-Jun HAN jae-moon PARK Hyung-Gil SEO Jong-Soo Samsung Ship Model Basin(SSMB) Marine Research InstituteSamsung Heavy IndustriesScience TownDaejeon 305-380Korea

Tip vortex cavitation noise of marine propeller became primary concems to reduce hazardous environmental impacts from commercial ship or to keep the underwater surveillance of naval ships. The investigations of the tip vortex and its induced noise are normally conducted through the model test in a water cavitation tunnel. However the Reynolds number of model-test is much smaller than that of the full-scale, which subsequently results in the difference of tip vortex cavitation inception. Hence, the scaling law between model- and full-scales needs to be identified prior to the prediction and assessment of propeller noise in full scale. From previous researches, it is generally known that the incipient caivtation number of tip vortex can be represented as a power of the Reynolds number. However, the power exponent for scaling, which is the main focus of this research, has not been clearly studied yet. This paper deals with the estimation of scaling exponent based on tip vortex cavitation inception test in both full- and model-scale ships. Acoustical measurements as well as several kind of signal processing technique for an inception criterion suggest the scaling exponent as 0.30. The scaling value proposed in this study shows slight difference to the one of most recent research. Besides, extrapolation of model-ship noise measurement using the proposed one predicts the full-scale noise measurement with an acceptable discrepancy.

关键词： tip vortex cavitation underwater radiated noise scaling exponent

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Comparison of macular changes according to the etiology of optic neuritis:a cross-sectional study

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International Journal of Ophthalmology(English edition) 2024年第4期17卷 686-692页

作者： Yeji moon Sung-Min Kim jae Ho Jung Department of Ophthalmology Asan Medical CenterUniversity of Ulsan College of MedicineSeoul 05505Republic of Korea Department of Neurology Seoul National University HospitalSeoul 03080Republic of Korea Department of Ophthalmology Seoul National University HospitalSeoul 03080Republic of Korea Department of Ophthalmology Seoul National University College of MedicineSeoul 03080Republic of Korea

AIM:To compare the macular structure including foveal thickness among patients with optic neuritis(ON)according to the etiology and to investigate the possible correlation between structural and visual outcomes METHODS:In this retrospective cross-sectional study,the clinical data of patients with aquaporin-4 immunoglobulin G-related ON(AQP4 group,40 eyes),myelin oligodendrocyte glycoprotein IgG-related ON(MOG group,31 eyes),and multiple sclerosis-related ON(MS group,24 eyes)were *** retinal thickness of the foveal,parafoveal and perifoveal regions were *** acuity(VA),visual field index and mean deviation were measured as visual ***:The AQP4 group showed a significantly thinner fovea(226.4±13.4μm)relative to the MOG(236.8±14.0μm,P=0.015)and MS(238.9±14.3μm,P=0.007)*** thickness in the parafoveal area also was thinner in the AQP4 group,though the difference in perifoveal retinal thickness was not *** thickness was correlated with VA in the AQP4 group(coefficientρ=-0.418,P=0.014),but not in the MOG and MS groups(P=0.218 and P=0.138,respectively).There was no significant correlation between foveal thickness and visual field test in all three ***:The significant thinning in the fovea and parafoveal areas in the AQP4 group compared to the MOG and MS groups are ***,macular changes in AQP4-ON show a significant correlation with *** results provide the possibility that retinal structural damage could reflect functional damage in AQP4-ON,distinct from MOGON and MS-ON.

关键词： foveal thickness optic neuritis aquaporin-4 immunoglobulin myelin oligodendrocyte glycoprotein multiple sclerosis

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Application of signal processing techniques to the detection of tip vortex cavitation noise in marine propeller

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Journal of Hydrodynamics 2013年第3期25卷 440-449页

作者： LEE Jeung-Hoon HAN jae-moon PARK Hyung-Gil SEO Jong-Soo Samsung Ship Model Basin (SSMB) Marine Research Institute Samsung Heavy Industries Science TownDaejeon 305-380 Korea

The tip vortex cavitation and its relevant noise has been the subject of extensive researches up to now. In most cases of experimental approaches, the accurate and objective decision of cavitation inception is primary, which is the main topic of this paper. Although the conventional power spectrum is normally adopted as a signal processing tool for the analysis of cavitation noise, a faithful exploration cannot be made especially for the cavitation inception. Alternatively, the periodic occurrence of bursting noise induced from tip vortex cavitation gives a diagnostic proof that the repeating frequency of the bursting contents can be exploited as an indication of the inception. This study, hence, employed the Short-Time Fourier Transform （STFT） analysis and the Detection of Envelope Modulation On Noise （DEMON） specmma analysis, both which are appropriate for finding such a repeating frequency. Through the acoustical measurement in a water tunnel, the two signal processing techniques show a satisfactory result in detecting the inception of tip vortex cavitation.

关键词： tip vortex cavitation inception Short-Time Fourier Transform (STFT) Detection of Envelope Modulation On Noise(DEMON)

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Improvements of model-test method for cavitation-induced pressure fluctuation in marine propeller

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Journal of Hydrodynamics 2013年第4期25卷 599-605页

作者： LEE Jeung-Hoon HAN jae-moon PARK Hyung-Gil SEO Jong-Soo Samsung Ship Model Basin (SSMB) Marine Research Institute Samsung Heavy Industries Science Town

Although the prediction of propeller cavitation-induced pressure fluctuation strongly depends on the model-scalemeasure- ment in a cavitation tunnel, there is still a lack of correlation with full-scale data. This paper deals with the enhancement of such a correlation deficiency by improving the conventional model-test technique, two majors of which are in the following. One is to take into account the boundary layer effect of wooden fairing plate at the ceiling of water cavitation tunnel. The other is to avoid the reso- nance frequency range of model-ship via adjusting the revolution speed of model propeller. Through a case study, for which both model and full-scale test data are available, the improved method in this study shows its validness, and furthermore a close correla- tion with full scale measurement.

关键词： cavitation boundary layer resonance

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Structural stability estimation of whirling unit

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中国有色金属学会会刊：英文版 2009年第B09期19卷 202-208页

作者： Son-jae HWAN Han-Chang WOO Lee-Sang RYONG Lee-Young moon Daegu Machinery Institute of Component & Materials Foundation Department of Automobile Yeungnam College of Science & Technology Department of Mechanical Engineering Kyung pook National University

Whirling is a cutting process in which a series of cutting edges on whirling ring remove material by turning over a rotating workpiece. In this study static and dynamic stability of whirling unit was estimated by using ADAMS and NASTRAN softwares. Each maximum force acting on the bearing attached to the spindle assembly and the cutting tool attached to the whirling ring with the rotating speed of 6 000 r/min was 235 N and 902 N respectively. The maximum stress of 0.74 MPa on the base frame is far smaller than the yield strength of 282 MPa. The calculated natural frequency of 148 Hz of the system is far from the frequency of the driving speed of 6 000 r/min. The experimentally obtained maximum cutting force of 792 N is smaller than that of calculated value. And the experimentally obtained natural frequency of 118 Hz is beyond the driving speed of 6000 r/min. From above results it can be judged that the whirling system is statically and dynamically stable.

关键词：旋转工件稳定性评价 NASTRAN软件动态稳定性结构单元固有频率行车速度

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