충돌분무의 액적 거동에 미치는 비등방성 난류특성의 영향에 대한 수치해석 연구

고권현(G. H. Ko),유홍선(H. S. Ryou) 한국전산유체공학회 2003 한국전산유체공학회지 Vol.8 No.4

It is an aim of this study to perform extensive numerical study for analyzing the anisotropic turbulence effects on spatial and temporal behaviors of droplet for impinging sprays. The turbulence model of Durbin is used for comparisons with the k-E model. The turbulence-induced dispersions of droplets are consider to describe the anisotropy of turbulence effectively and spray/wall interactions are simulated using the model of Lee and Ryou. Present study investigates the overall and the internal structures of impinging diesel sprays such as spray shapes, radius and height of wall sprays, Sauter mean diameter (SMD), local droplet velocity, and local gas velocity and compared the results with experimental data by two adopted turbulence models. When the anisotropy effect of turbulence is included, better predictions for both gas and droplet tangential velocities are obtained, compared to the k-ε model. It is concluded that anisotropic effect of turbulence should be considered for simulating impinging diesel sprays.

Host People's Kindness and Migrant Workers' Cultural Adaptation: Evidence from South Korea

Jihyun Ryou(Jihyun Ryou),Sang-Yeon Kim(Sang-Yeon Kim) 한국학술연구원 2022 Korea Observer Vol.53 No.4

This study purports to determine the predictors of migrant workers' cultural adaptation in South Korea. In the main, we examined the extent to which the level of inter-/intracultural socializing, exposure to local/native media, and host culture receptivity affect the level of cultural adaptation in cognitive, affective, behavioral domains. Potential impacts of demographic factors (e.g., age, sex, ethnicity, marital status, living alone vs. with family, education level, residency in years, perceived cultural similarity) were also explored. To find answers to the research questions, a total of 634 migrant workers from 37 different nations were reached using a snowball sampling. Surveys were collected in 12 districts of Seoul, the capital of South Korea, and 21 adjacent metropolitan areas. Results indicate that intercultural interaction with host people and media exposure to local contents tend to help improve their knowledge about South Korea (e.g., language, culture). With all else equal, migrant workers treated kindly by Koreans at the workplace and in service sectors, and those living with family, compared to those who live alone, tended to enjoy a greater satisfaction with work and life in South Korea and were more willing to stay. Practical implications for Korean policymakers include encouraging competent migrant workers to move together with the family, making administrative efforts to further simplify the documentation process, and initiating public campaigns to raise host culture receptivity among Korean citizens.

Development and Application of a New Spray Impingement Model Considering Film Formation in a Diesel Engine

Ryou, Hong-Sun,Lee, Seong-Hyuk,Ko, Gwon-Hyun,Hong, Ki-Bae The Korean Society of Mechanical Engineers 2001 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.15 No.7

The present article presents an extension to the computational model for spray/wall interaction and liquid film processes that has been dealt with in the earlier studies (Lee and Ryou, 2000a). The extensions incorporate film spread due to impingement forces and dynamic motion induced by film inertia to predict the dynamic characteristics of wall films effectively. The film model includes the impingement pressure of droplets, tangential momentum transfer due to the impinging droplets on the film surface and the gas shear force at the film surface. Validation of the spray/wall interaction model and the film model was carried out for non-evaporative diesel sprays against several sources of experimental data. The computational model for spray/wall interactions was in good agreement with experimental data for both spray radius and height. The film model in the present work was better than the previous static film model, indicating that the dynamic effects of film motion should be considered for wall films. On the overall the present film model was acceptable for predication of the film radius and thickness.

Lithium-Ion Batteries: Excellent Cycle Life of Lithium-Metal Anodes in Lithium-Ion Batteries with Mussel-Inspired Polydopamine-Coated Separators (Adv. Energy Mater. 6/2012)

Ryou, Myung-Hyun,Lee, Dong Jin,Lee, Je-Nam,Lee, Yong Min,Park, Jung-Ki,Choi, Jang Wook Wiley (John WileySons) 2012 ADVANCED ENERGY MATERIALS Vol.2 No.6

Gold nanoparticle-DNA aptamer composites as a universal carrier for in vivo delivery of biologically functional proteins

Ryou, S.M.,Yeom, J.H.,Kang, H.J.,Won, M.,Kim, J.S.,Lee, B.,Seong, M.J.,Ha, N.C.,Bae, J.,Lee, K. Elsevier Science Publishers 2014 Journal of controlled release Vol.196 No.-

Although the delivery of biologically functional protein(s) into mammalian cells could be of tremendous value to biomedical research, the development of such technology has been hindered by the lack of a safe and effective delivery method. Here, we present a simple, efficient, and versatile gold nanoparticle-DNA aptamer conjugate (AuNP-Apt)-based system, with nanoblock-like properties, that allows any recombinant protein to be loaded without additional modifications and delivered into mammalian living systems. AuNP-Apt-based protein delivery system was able to deliver various proteins into variety of cell types in vitro without showing cytotoxicity. This AuNP-Apt system was also effective for the local and systemic targeted delivery of proteins in vivo. A local injection of the AuNP-Apt loaded with the apoptosis-inducing BIM protein efficiently inhibited the growth of xenograft tumors in mice. Furthermore, an intravenous injection of AuNP-Apt loaded with both epidermal growth factor (EGF) and BIM resulted in the targeted delivery of BIM into a xenograft tumor derived from EGF receptor-overexpressing cancer cells with no detectable systemic toxicity. Our findings show that this system can serve as an innovative platform for the development of protein-based biomedical applications.

Invariant Trace Fields of Chain Links

Ryou, Kazuhiro Department of Mathematics 2016 Kyungpook mathematical journal Vol.56 No.1

In this paper, we compute the trace field of C(2, s), the complement of two component chain link with s left half twists in ${\mathbb{S}}^3$, for every s. As a result, for every $n{\in}{\mathbb{N}}{\backslash}\{1\}$, we can find $s{\in}{\mathbb{Z}}$ such that the degree of the trace field of C(2, s) is n. We also prove that if for fixed p, the degree of the trace field of C(p, s) runs over ${\mathbb{N}}{\backslash}\{1\}$, then p is contained in {1, 2, 4, 8}.

Shiga-like toxin-based high-efficiency and receptor-specific intracellular delivery system for a protein

Ryou, Jeong-Hyun,Sohn, Yoo-Kyoung,Hwang, Da-Eun,Kim, Hak-Sung Elsevier 2015 Biochemical and biophysical research communication Vol.464 No.4

<P><B>Abstract</B></P> <P>The cell-specific cytosolic delivery of functional macromolecules with high efficiency is of great significance in molecular medicine and biotechnology. Herein, we present a Shiga-like toxin II-based high-efficiency and receptor-specific intracellular delivery system. We designed and constructed the Shiga-like toxin-based carrier (STC) to comprise the targeting and translocation domains, and used it for delivering a protein cargo. The STC was shown to deliver a protein cargo into the cytosol with high efficiency in a receptor-specific manner, exhibiting much higher efficiency than the most widely used cell-penetrating peptide. The general utility of the STC was demonstrated by modulating the targeting domain. The present delivery platform can be widely used for the intracellular delivery of diverse biomolecules in a receptor-specific and genetically encodable manner.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We present a highly efficient and cell-specific intracellular delivery system. </LI> <LI> Shiga-like toxin-based carrier comprises the targeting and translocation domain. </LI> <LI> EGFP was successfully delivered into the cytoplasm of mammalian cells. </LI> <LI> The receptor-specificity was changed by modulating the targeting domain. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Reproducibility of cardiopulmonary exercise testing between one after and 1–3 weeks after elective percutaneous coronary intervention

Ryou Tanaka,Isao Waki,Shigeshi Kamikawa,Daiki Yamashita,Natsumi Tabita,Saori Nishimura,Shunich Higashiya,Hirosuke Yamaji,Takashi Murakami,Shozo Kusachi 한국운동재활학회 2023 JER Vol.19 No.5

Prompt prescription and early initiation of exercise training are essential for patients undergoing elective percutaneous coronary intervention (PCI). We hypothesized that cardiopulmonary exercise testing (CPET) parameters determined the day after elective PCI during hospitalization would not differ from those obtained 1–3 weeks post-PCI in patients with stable coronary heart disease (CHD). CPET was performed the day after and 1–3 weeks (13±4.6; 7–21 days) after PCI. CPET was performed with a bicycle ergometer up to the ventilatory aerobic threshold (VAT) on the day after PCI. Symptom-limited CPET was conducted 1–3 weeks after PCI. No complications arose from the tests. There were no significant differences in %VAT (next day: 88.6± 16.7 vs. 1–3 weeks later: 91.4%±18.7%), the workload at the VAT (51.8±11.0 W vs. 52.9± 11.6 W), heart rate (HR) at the VAT (95.3±105 beats/min vs. 94.1±11.3 beats/min), or metabolic equivalent (METs) at the VAT (3.69±0.69 vs. 3.84±0.78) between the two sessions. The slope of linear regression for two repeated measurements was close to 1 (%VAT, 1.02; workload at the VAT, 0.95; METs at the VAT, 1.03), except for HR (0.70). Bland–Altman plots revealed the reproducibility of all four CPET measurements between the two sessions. In conclusion, CPET up to the VAT can be performed safely 1-day post-PCI in patients with stable CHD. CPET parameters do not significantly differ between testing performed the day after and 1–3 weeks after PCI. Next-day CPET during hospitalization after PCI may enable prompt exercise prescription without the need for another CPET 1–3 weeks later.

Inhibition of xenograft tumor growth in mice by gold nanoparticle-assisted delivery of short hairpin RNAs against Mcl-1L

Ryou, S.M.,Park, M.,Kim, J.M.,Jeon, C.O.,Yun, C.H.,Han, S.H.,Kim, S.W.,Lee, Y.,Kim, S.,Han, M.S.,Bae, J.,Lee, K. Elsevier Science Publishers 2011 Journal of biotechnology Vol.156 No.2

A prerequisite for the therapeutic use of small RNAs is the development of a method that can deliver them into animals. Previous studies have shown the capability of functionalized gold nanoparticles to serve as a general platform for loading and delivering DNA oligonucleotides and short hairpin RNAs (shRNAs) into cultured human cells. Here, we report the ability of the gold nanoparticle-assisted gene delivery system (AuNP-GDS) to deliver shRNA to a xenograft tumor in a mouse model. AuNP-GDS delivery of in vitro synthesized shRNA targeted to the Mcl-1L gene knocked down levels of Mcl-1L mRNA and protein by ∼36% and ∼26%, respectively, which were sufficient to induce apoptosis of the xenograft tumor cells and consequently inhibited the development of the tumor. We demonstrated that our lego-like AuNP-GDS, which can easily load and deliver shRNAs targeted to any gene of interest into living systems, can deliver shRNAs into xenograft tumors, leading to antitumor activity in an animal model.

Task Allocation in an N-Cube Multiprocessor System

Ryou, Jea-Cheol 충남대학교 자연과학연구소 1992 忠南科學硏究誌 Vol.19 No.2

하이퍼큐브 다중프로세서는 그들의 상호연결특징에 의하여 이상적인 병렬구조로 알려지고있다. 하이퍼큐브에서 하나의 테스크를 수행하기 위해서는 다중프로세서들 중에서 한 서브큐브에 테스크를 할당해야 하는데, 이러한 할당문제는 시스템성능에 중요한 영향을 미치고 있다. 본 논문에서는 테스크를 할당하기 위하여 하나의 서브큐브를 탐색하는 알고리즘을 제시하고자 한다. 전체 하이퍼큐브가 어느 테스크에게도 할당되지 않은 자유로운 상태라면, 어떤 크기의 서브큐브라도 쉽게 탐색할수 있지만, 일부의 프로세서가 어느 테스크에 할당이 되어 있으면 이러한 문제는 NP-Complete이다. 제시하고자하는 알고리즘의 기본방향은 일단 하이퍼큐브를 2차원의 격자구조로 변환하여 서브큐브를 이루는 프로세서들을 결정론적으로 탐색하는 것이다. 이 알고리즘이 지금까지 알려진 방법들보다 향상된 서브큐브 인지능력이 있음을 보였다. The n-dimensional hypercube multiprocessor is considered as ideal parallel architectures for their powerful interconnection features. A task arriving at a hypercube must be assigned to a subcube in the multiprocessor for execution. Efficient allocation of processors in a hypercube is a key to its performance and utilization. The purpose of this paper is to study how to find a free subcube to allocate an incoming task. When the entire hypercube is free, subcubes of arbitrary dimension can be imbedded in it. But if some processors have been assigned to other tasks, then the general mapping problem is NP-complete. The idea of the proposed algorithm is to map a hypercube to a two-dimensional grid structure and then deterministically find a set of free processor which form a subcube. We show that the proposed algorithm has enhanced subcube recognition capability than any existing algorithms.