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Corrugated surface microparticles with chitosan and levofloxacin for improved aerodynamic performance

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Asian Journal of Pharmaceutical Sciences 2023年第3期18卷 146-158页

作者： Chang-soo Han Ji-Hyun Kang Eun hye Park Hyo-jung Lee so-Jeong Jeong Dong-Wook kim Chun-Woong Park College of Pharmacy Chungbuk National UniversityCheongju 28160Republic of Korea School of Pharmacy Jeonbuk National UniversityJeonju 54896Republic of Korea College of Pharmacy Wonkwang UniversityIksan 54538Republic of Korea

Corrugated surface microparticles comprising levofloxacin(LEV),chitosan and organic acid were prepared using the 3-combo spray drying *** amount and the boiling point of the organic acid affected the degree of *** this study,we tried to improve the aerodynamic performance and increase aerosolization by corrugated surface microparticle for lung drug delivery efficiency as dry powder ***175 L20 prepared with 175 mmol propionic acid solution was corrugated more than HMF175 L20 prepared with 175 mmol formic acid *** ACI and PIV results showed a significant increase in aerodynamic performance of corrugated *** FPF value of HMP175 L20 was 41.3%±3.9%compared with 25.6%±7.7%of HMF175 *** microparticles also showed better aerosolization,decreased x-axial velocity,and variable *** dissolution of drug formulationswas observed in *** administered to the lungs achieved higher LEV concentrations in the lung fluid than high doses administered *** modification in the polymer-based formulation was achieved by controlling the evaporation rate and improving the inhalation efficiency of DPIs.

关键词： Chitosan Organic acid Levofloxacin Corrugated surface Aerodynamic performance

An estimation of vehicle kilometer traveled and on-road emissions using the traffic volume and travel speed on road links in Incheon City

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Journal of Environmental Sciences 2017年第4期29卷 90-100页

作者： Sungwoon jung Jounghwa kim Jeongsoo kim Dahee Hong Dongjoo Park Transportation Pollution Research Center National Institute of Environmental Research Center for Korea Transport Database The Korea Transport Institute Department of Transportation Engineering University of Seoul

The objective of this study is to estimate the vehicle kilometer traveled（VKT） and on-road emissions using the traffic volume in urban. We estimated two VKT; one is based on registered vehicles and the other is based on traffic volumes. VKT for registered vehicles was 2.11 times greater than that of the applied traffic volumes because each VKT estimation method is different. Therefore, we had to define the inner VKT is moved VKT inner in urban to compare two values. Also, we focused on freight modes because these are discharged much air pollutant emissions. From analysis results, we found middle and large trucks registered in other regions traveled to target city in order to carry freight, target city has included many industrial and logistics areas. Freight is transferred through the harbors,large logistics centers, or via locations before being moved to the final destination. During this process, most freight is moved by middle and large trucks, and trailers rather than small trucks for freight import and export. Therefore, these trucks from other areas are inflow more than registered vehicles. Most emissions from diesel trucks had been overestimated in comparison to VKT from applied traffic volumes in target city. From these findings, VKT is essential based on traffic volume and travel speed on road links in order to estimate accurately the emissions of diesel trucks in target city. Our findings support the estimation of the effect of on-road emissions on urban air quality in Korea.

关键词： Vehicle kilometer traveled On-road emissions Traffic volume Travel speed Diesel trucks

New Precoded Spatial-Multiplexing for an Erasure Event in Single Frequency Networks

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China Communications 2018年第4期15卷 130-140页

作者： hojun kim seyoung kim yulong shang seunghyeon kim taejin jung Department of Electronics and Computer Engineering Chonnam National University Gwangju 61186 Republic of Korea R＆D Planning and Management Team Giga KOREA Foundation Daejcon 34054 Republic of Korea

In this paper, we propose a new spatial-multiplexing(SM) scheme employing an orthogonal precoder over Rayleigh-fading channels for an erasure event in single frequency networks(SFN). To optimize the precoder, the average bit error rate(BER) is evaluated and minimized through a mathematical analysis. Compared to an ordinary SM, the proposed scheme guarantees identical BER performance under non-erasure fading channels and achieves a greatly improved performance under erasure fading channels, especially for a higher erasure-ratio and SNR values. This improvement is mainly due to the increase in the diversity gain incurred by the optimized precoder over the erasure event. We also compare the performance of the proposed SM to that of the conventional constellation-rotation(CR) scheme applied to the single antenna SFN systems. The results of a computer simulation show that the performance of the new scheme is more effective than that of a conventional CR across all simulation cases.

关键词： Spatial-multiplexing single fre-quency network Rayleigh fading constella-tion-rotation broadcasting systems.

Slip-enhanced Reverse Electrodialytic Power Generation in Ion-selective Nanochannels

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Journal of Thermal Science 2013年第1期22卷 36-41页

作者： Byeongdong Kang Jaisuk Yoo Hyun jung kim Dong-Kwon kim Department of Mechanical Engineering Ajou University

Power generation by reverse electrodialysis in ion-selective nanochannels is numerically investigated. Especially,in the present study, the influence of hydrodynamic slip at the surface of nanochannels is investigated. The current-potential characteristics of the nanochannels are calculated by solving several governing equations:Nernst-Planck equation for the ionic concentrations, the Poisson equation for the electric potential, and the Navier-Stokes equation for the diffusioosmotic flow. Hydrodynamic slip is applied as the boundary condition at the surface of nanochannels. As the slip length increases, the diffusioosmotic flow velocity and electrical conductance of ions increase because the friction at the surface of nanochannels decreases. It is shown that the power generation is enhanced by 44% with a moderate 100nm slip length by using a nanochannel with 10nm height.

关键词： Reverse electrodialysis Ion-selective nanochannel Power generation Slip length

Assessing significant fibrosis using imaging-based elastography in chronic hepatitis B patients: Pilot study

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World Journal of Gastroenterology 2019年第25期25卷 3256-3267页

作者： Hee Sun Park Won Hyeok Choe Hye Seung Han Mi Hye Yu Young Jun kim Sung Il jung Jeong Han kim so Young Kwon Department of Radiology Konkuk University School of MedicineSeoul 05030South Korea Department of Internal Medicine Konkuk University School of MedicineSeoul 05030South Korea Department of Pathology Konkuk University School of MedicineSeoul 05030South Korea

BACKGROUND Accurate detection of significant fibrosis(fibrosis stage 2 or higher on the METAVIR scale)is important especially for chronic hepatitis B(CHB)patients with high viral loads but with normal or mildly elevated alanine aminotransferase(ALT)levels because the presence of significant fibrosis is accepted as the indication for antiviral *** biopsy is the reference standard for diagnosing significant fibrosis,but it is an invasive ***,noninvasive imaging-based measurements,such as magnetic resonance elastography(MRE)or two-dimensional shear-wave elastography(2DSWE),have been proposed for the quantitative assessment of liver *** To explore MRE and 2D-SWE to identify fibrosis stage,and to compare their performance with that of serum-based *** The study enrolled 63 treatment-na?ve CHB patients with high viral loads but with normal or mildly elevated ALT levels who underwent liver biopsy before a decision was made to initiate antiviral *** and 2D-SWE were performed,and serum-based indices,such as FIB-4 and aspartate transaminase to platelet ratio index(APRI),were *** diagnostic performances of MRE,2D-SWE,FIB-4,and APRI for assessing significant fibrosis(≥F2)and cirrhosis(F4)were evaluated with liver histology as the reference standard,using receiver operating characteristic *** The liver fibrosis stage was F0/F1 in 19,F2 in 14,F3 in 14,and F4 in 16 patients,*** significantly discriminated F2 from F0/1(P=0.022),whereas 2D-SWE showed a broad overlap in distinguishing those *** showed a higher correlation coefficient value with fibrosis stage than 2D-SWE with fibrosis stage(0.869 vs 0.649,Spearman test;P<0.001).Multivariate linear regression analyses showed that fibrosis stage was the only factor affecting the values of MRE(P<0.001),whereas body mass index(P=0.042)and fibrosis stage(P<0.001)were independent factors affecting 2D-SWE *** performance for diagnos

关键词： Antiviral therapy Chronic hepatitis B Liver fibrosis Magnetic resonance elastography Ultrasound elastography

A Novel Transparent and Auditable Fog-Assisted Cloud Storage with Compensation Mechanism

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Tsinghua Science and Technology 2020年第1期25卷 28-43页

作者： Donghyun kim junggab son Daehee Seo Yeojin kim Hyobin kim jung Taek Seo Department of Computer Science Kennesaw State UniversityMariettaGA 30060USA Department of Information Security Engineering Soonchunhyang UniversityAsan 31538South Korea

This paper introduces a new fog-assisted cloud storage which can achieve much higher throughput compared to the traditional cloud-only storage architecture by reducing the traffics toward the cloud storage. The fog-storage service providers are transparency to end-users and therefore, no modification on the end-user devices is necessary. This new system is featured with(1) a stronger audit scheme which is naturally coupled with the proposed architecture and does not suffer from the replay attack and(2) a transparent and efficient compensation mechanism for the fog-storage service providers. We provide rigorous theoretical analysis on the correctness and soundness of the proposed system. To the best of our knowledge, this is the first paper to discuss about a storage data audit scheme for fog-assisted cloud storage as well as the compensation mechanism for the service providers of the fog-storage service providers.

关键词： fog computing cloud computing network storage data audit merkle hash tree integer factorization payment transparency

Chemical surface tuning of zinc metal anode toward stable,dendrite-less aqueous zinc-ion batteries

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Journal of Energy Chemistry 2023年第11期86卷 1-8,I0001页

作者： Pranav Kulkarni Sun-Sik kim Hyun Young jung Department of Energy Engineering Gyeongsang National UniversityJinju-siGyeongnam 52725South Korea Department of Energy System Engineering Gyeongsang National UniversityJinju-siGyeongnam 52725South Korea

The commercialization of Zn batteries is confronted with urgent challenges in the metal anode,such as dendrite formation,capacity loss,and cracking or ***,surface interfacial engineering of the Zn anode is introduced for achieving safety and dendritic-free cycling for high-performance aqueous Zn batteries through a simple but highly effective chemical etching-substitution *** chemical modification induces a rough peak-valley surface with a thin fluorine-rich interfacial layer on the Zn anode surface,which regulates the growth orientation via guiding uniform Zn plating/stripping,significantly enhances accessibility to aqueous electrolytes and improves wettability by reducing surface *** a result,such a synergetic surface effect enables uniform Zn plating/stripping with low polarization of 29 m V at a current density of 0.5 m A cm^(-2) with stable cyclic performance up to 1000 ***,a full cell composed of a fluorine-substituted Zn anode coupled with aβ-MnO_(2)or Ba-V_(6)O_(13)cathode demonstrates improved capacity retention to 1000 cycles compared to the pristine-Zn *** proposed valley deposition model provides the practical direction of surface-modified interfacial chemistries for improving the electrochemical properties of multivalent metal anodes via surface tuning.

关键词： Dendrite free Peak-Valley surface Zinc-ion batteries Surface modification Fluorinated interface

Stiefel–Whitney classes and topological phases in band theory

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Chinese Physics B 2019年第11期28卷 1-17页

作者： Junyeong Ahn Sungjoon Park Dongwook kim Youngkuk kim Bohm-jung Yang Department of Physics and Astronomy Seoul National UniversitySeoul 08826Korea Center for Correlated Electron Systems Institute for Basic Science(IBS)Seoul 08826Korea Center for Theoretical Physics(CTP) Seoul National UniversitySeoul 08826Korea

We review the recent progress in the study of topological phases in systems with space–time inversion symmetry *** an anti-unitary symmetry which is local in momentum space and satisfies I2 ST= 1 such as PT in two dimensions(2 D)and three dimensions(3 D) without spin–orbit coupling and C2 T in 2 D with or without spin–orbit coupling, where P, T, C2 indicate the inversion, time-reversal, and two-fold rotation symmetries, respectively. Under IST, the Hamiltonian and the periodic part of the Bloch wave function can be constrained to be real-valued, which makes the Berry curvature and the Chern number vanish. In this class of systems, gapped band structures of real wave functions can be topologically distinguished by the Stiefel–Whitney numbers instead. The first and second Stiefel–Whitney numbers w1 and w2, respectively,are the corresponding invariants in 1 D and 2 D, which are equivalent to the quantized Berry phase and the Z2 monopole charge, respectively. We first describe the topological phases characterized by the first Stiefel–Whitney number, including1 D topological insulators with quantized charge polarization, 2 D Dirac semimetals, and 3 D nodal line semimetals. Next we review how the second Stiefel–Whitney class characterizes the 3 D nodal line semimetals carrying a Z2 monopole *** particular, we explain how the second Stiefel–Whitney number w2, the Z2 monopole charge, and the linking number between nodal lines are related. Finally, we review the properties of 2 D and 3 D topological insulators characterized by the nontrivial second Stiefel Whitney class.

关键词： topological semimetal

Effects of compressive stress on the nonlinear electromechanical behavior of ferroelectric ceramics

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Science China(Technological Sciences) 2006年第1期49卷 29-37页

作者： LEE jung-Ju kim Hyun Cheol Department of Mechanical Engineering KAIST Taejon 305-701 Korea

The effects of compressive stress parallel and perpendicular to the polar axis of PZT ceramics on the nonlinear electromechanical behavior of the materials has been experimentally studied. A domain-switching model that divides each 180° switching to two successive 90° switching is proposed to explain these effects. In the case of stress parallel to the polar axis, domain switching in the ceramics is approximately axisymmetric and can be simulated by an analytical model. While in the case of stress perpendicular to the polar axis, domain switching is three-dimensional and cannot be simplified. The simulated re-sults that match the experiments well show the validity of the proposed domain-switching model.

关键词： ferroelectric ceramics, domain switching, electromechanical, PZT.