Comparison of Fatigue Provisions in Various Codes and Standards -Part 1: Basic Design S-N Curves of Non-Tubular Steel Members

Sungwoo Im,Joonmo Choung 한국해양공학회 2021 韓國海洋工學會誌 Vol.35 No.2

For the fatigue design of offshore structures, it is essential to understand and use the S-N curves specified in various industry standards and codes. This study compared the characteristics of the S-N curves for five major codes. The codes reviewed in this paper were DNV Classification Rules (DNV GL, 2016), ABS Classification Rules (ABS, 2003), British Standards (BSI, 2015), International Welding Association Standards (IIW, 2008), and European Standards (BSI, 2005). Types of stress, such as nominal stress, hot-spot stress, and effective notch stress, were analyzed according to the code. The basic shape of the S-N curve for each code was analyzed. A review of the survival probability of the basic design S-N curve for each code was performed. Finally, the impact on the conservatism of the design was analyzed by comparing the S-N curves of three grades D, E, and F by the five codes. The results presented in this paper are considered to be a good guideline for the fatigue design of offshore structures because the S-N curves of the five most-used codes were analyzed in depth.

Visible-Light-Induced C-O Bond Formation for the Construction of Five- and Six-Membered Cyclic Ethers and Lactones

Im, Honggu,Kang, Dahye,Choi, Soyeon,Shin, Sanghoon,Hong, Sungwoo American Chemical Society 2018 ORGANIC LETTERS Vol.20 No.23

<P>Visible-light-induced intramolecular C-O bond formation was developed using 2,4,6-triphenylpyrylium tetrafluoroborate (TPT), which allows the regiocontrolled construction of cyclic ethers and lactones. The reaction is likely to proceed through the single-electron oxidation of the phenyl group, followed by the formation of a benzylic radical, thus preventing a competing 1,5-hydrogen abstraction pathway. Detailed mechanistic studies suggest that molecular oxygen is used to trap the radical intermediate to form benzyl alcohol, which undergoes cyclization. This new approach serves as a powerful platform by providing efficient access to valuable five- and six-membered cyclic ethers and lactones with a unified protocol.</P> [FIG OMISSION]</BR>

Performance of light-emitting-diode based on quantum dots.

Kim, Sungwoo,Im, Sang Hyuk,Kim, Sang-Wook RSC Pub 2013 Nanoscale Vol.5 No.12

<P>Light-emitting diodes (LEDs) based on colloidal quantum dots (QDs) have attracted considerable attention due to their potential in applications such as color-saturated displays and white light with high color-rendering index. However, cadmium-based QD-LEDs are strictly regulated in industrial applications because of the high toxicity of cadmium. As an alternative, InP-based cadmium-free QDs are recommended owing to their wide emission range that is comparable to that of CdSe, and their environmentally friendly properties when applied to QD-LEDs and white QD-LEDs. This feature article provides an overview of QDs' merits in display and light-emitting applications as well as a discussion of their color tunability, photo-stability, and high luminescence efficiency. We will include optical down-conversion devices using various QDs, electroluminescent devices based on organic and inorganic charge-transporting layers, and printing methods using cadmium based and cadmium free QDs.</P>

Air-stable and efficient inorganic–organic heterojunction solar cells using PbS colloidal quantum dots co-capped by 1-dodecanethiol and oleic acid

Kim, Sungwoo,Im, Sang Hyuk,Kang, Meejae,Heo, Jin Hyuck,Seok, Sang Il,Kim, Sang-Wook,Mora-Seró,, Ivá,n,Bisquert, Juan The Royal Society of Chemistry 2012 Physical chemistry chemical physics Vol.14 No.43

<P>PbS colloidal quantum dot (CQD)-sensitized inorganic–organic heterojunction solar cells fabricated by using the PbS CQDs co-capped by the oleic acid (OA) and 1-dodecanethiol (DT) ligand showed better device stability with aging time under ambient conditions without encapsulation. Furthermore, the device performance is better than the cell fabricated from PbS CQDs without DT ligand. The enhancement of performance in OA and DT co-capped systems is investigated by impedance spectroscopy. An upward displacement of the TiO<SUB>2</SUB> conduction band, with a consequent increase of <I>V</I><SUB>oc</SUB>, results in the improved performance when CQD with DT are employed.</P> <P>Graphic Abstract</P><P>PbS colloidal quantum dot (CQD)-sensitized inorganic–organic heterojunction solar cells fabricated by using the PbS CQDs co-capped by the oleic acid (OA) and 1-dodecanethiol (DT) ligand showed better device stability with aging time under ambient conditions without encapsulation. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2cp43223d'> </P>

Type-safe higher-order channels with channel locality

PARK, SUNGWOO,IM, HYEONSEUNG Cambridge University Press 2009 Journal of functional programming Vol.19 No.1

<B>Abstract</B><P>As a means of transmitting not only data but also code encapsulated within functions, higher-order channels provide an advanced form of task parallelism in parallel computations. In the presence of mutable references, however, they pose a safety problem because references may be transmitted to remote threads where they are no longer valid. This paper presents an ML-like parallel language with <I>type-safe</I> higher-order channels. By type safety, we mean that no value written to a channel contains references, or equivalently, that no reference escapes via a channel from the thread where it is created. The type system uses a typing judgment that is capable of deciding whether the value to which a term evaluates contains references or not. The use of such a typing judgment also makes it easy to achieve another desirable feature of channels, <I>channel locality</I>, that associates every channel with a unique thread for serving all values addressed to it. Our type system permits mutable references in sequential computations and also ensures that mutable references never interfere with parallel computations. Thus, it provides both flexibility in sequential programming and ease of implementing parallel computations.</P>

Development and characterization of high efficiency fine dust filter

Taein Im,Yongkyun Lee,Jiyong Jeong,Sungwoo Han,Oyoung Kwon,Jihyun Bae,Woonjung Kim 한국분석과학회 2017 학술대회논문집 Vol.2017 No.11

Fabrication of CuInTe₂ and CuInTe_2–<i>x</i>Se_<i>x</i> Ternary Gradient Quantum Dots and Their Application to Solar Cells

Kim, Sungwoo,Kang, Meejae,Kim, Seajin,Heo, Jin-Hyuk,Noh, Jun Hong,Im, Sang Hyuk,Seok, Sang Il,Kim, Sang-Wook American Chemical Society 2013 ACS NANO Vol.7 No.6

<P>We report the first synthesis of colloidal CuInTe<SUB>2</SUB>, CuInTe<SUB>2–<I>x</I></SUB>Se<SUB><I>x</I></SUB> gradient alloyed quantum dots (QDs) through a simple hot injection method. We confirmed the composition of synthesized QDs to cationic rich phase of CuIn<SUB>1.5</SUB>Te<SUB>2.5</SUB> and Cu<SUB>0.23</SUB>In<SUB>0.36</SUB>Te<SUB>0.19</SUB>Se<SUB>0.22</SUB> with XPS and ICP analysis, and we have also found that the gradient alloyed Cu<SUB>0.23</SUB>In<SUB>0.36</SUB>Te<SUB>0.19</SUB>Se<SUB>0.22</SUB> QDs exhibit greatly improved stability over the CuIn<SUB>1.5</SUB>Te<SUB>2.5</SUB> QDs. The solution-processed solar cell based on the gradient alloyed Cu<SUB>0.23</SUB>In<SUB>0.36</SUB>Te<SUB>0.19</SUB>Se<SUB>0.22</SUB> QDs exhibited 17.4 mA/cm<SUP>2</SUP> of short circuit current density (<I>J</I><SUB>sc</SUB>), 0.40 V of open circuit voltage (<I>V</I><SUB>oc</SUB>), 44.1% of fill factor (FF), and 3.1% of overall power conversion efficiency at 100 mW/cm<SUP>2</SUP> AM 1.5G illumination.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2013/ancac3.2013.7.issue-6/nn401274e/production/images/medium/nn-2013-01274e_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn401274e'>ACS Electronic Supporting Info</A></P>

Identification of the primary determining factor(s) governing the oral absorption of edaravone in rats

Hyung, Sungwoo,Jeong, Yoo-Seong,Yeo, Jungmin,Song, Yoo-Kyung,Kim, Min-Soo,Im, Young-Jae,Maeng, Han-Joo,Chung, Suk-Jae Elsevier 2018 European journal of pharmaceutical sciences Vol.123 No.-

<P><B>Abstract</B></P> <P>This study was performed to determine the primary factor(s) governing the oral absorption of edaravone, a novel anti-oxidant for the treatment of amyotrophic lateral sclerosis, in rats. While the aqueous solubility of edaravone widely varied depending on the vehicle used, the oral bioavailability of the drug was not low when it was adequately solubilized, as evidenced by the fact that the oral exposure was high (in terms of the absolute bioavailability of 50–90%) at all dose ranges (i.e., 0.5–27 mg/kg) under solubilized conditions in rats. The sum of the in vitro clearance values for edaravone, 12.7 mL/(min × kg), obtained from metabolic stability studies with tissue-homogenates from the rat liver, kidney, intestine, and with the rat plasma, was found to be virtually identical to the systemic clearance of the drug in rats. It was noted that the liver represented over 83.9% of the total elimination with a hepatic extraction ratio of approximately 0.137, indicative of the minor role of hepatic first pass metabolism in the systemic absorption of edaravone after its oral administration. In studies with Ussing chamber with rat intestinal segments and Madin-Darby canine kidney (MDCKII) cells, edaravone was found to be highly permeable (i.e., P<SUB>app</SUB> over 10 × 10<SUP>−6</SUP> cm/s), and appeared to be a substrate for rat P-glycoprotein (P-gp; estimated K<SUB>m</SUB> of 421 μM). In contrast, however, the drug did not appear to be a substrate for human P-gp in transport studies with MDCKII-hMDR1 cells. Collectively, these observations suggest that the primary determining factor for the intestinal absorption of edaravone is its solubilization in vehicle/intestinal fluids, rather than permeability, pre-systemic first-pass metabolism, or efflux transport. Considering the fact that the newly approved indication of the drug would require prolonged administration, probably via oral administration, the findings reported herein provide relevant information regarding its use.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Bandgap engineered monodisperse and stable mercury telluride quantum dots and their application for near-infrared photodetection

Kim, Sungwoo,Kim, Taehoon,Im, Sang Hyuk,Seok, Sang Il,Kim, Kang Wook,Kim, Sungjee,Kim, Sang-Wook Royal Society of Chemistry 2011 Journal of materials chemistry Vol.21 No.39

<P>Bandgap-engineered monodisperse HgTe NCs of different sizes were synthesized by means of a facile temperature-control method, a non-aqueous and non-Te-gas process. The photo-physical properties of the synthesized NCs in a simple photovoltaic device were tested. It was shown that this cell is capable of processing signals up to the 100 kHz level below 3 dB and hence is suitable for use in NIR photodetection.</P> <P>Graphic Abstract</P><P>Bandgap-engineered monodisperse HgTe NCs were synthesized by temperature-control method, a non-aqueous and non-Te-gas process. The NCs were tested in a simple photovoltaic device, which showed that this cell is capable of processing signals up to the 100 kHz level below 3 dB. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c1jm12436f'> </P>

재귀모듈 프로그래밍을 위한 타입시스템의 설계

임현승(Hyeonseung Im),임정표(Jeongpyo Lim),박성우(Sungwoo Park) 한국정보과학회 2012 한국정보과학회 학술발표논문집 Vol.39 No.1A

ML 언어에서 제공하는 모듈 시스템은 강력한 모듈화 프로그래밍과 데이터 추상화를 지원함에도 불구하고 재귀모듈을 지원하지 못한다는 점이 단점으로 지적되어 왔다. 재귀모듈을 이용하면 상호의존적이지만 개념적으로는 서로 분리된 소프트웨어 컴포넌트들을 각각 다른 모듈에 작성할 수 있기 때문에 코드의 재사용성을 더욱 증진시킬 수 있다. 이러한 중요성 때문에 재귀모듈은 지난 10년 동안 프로그래밍 언어 분야에서 깊이 있게 연구되어 왔다. 그러나 기존 연구는 복시문제와 순환타입문제를 완벽하게 해결하지 못하여 한정된 재귀모듈 프로그래밍 패턴만을 지원하는 한계점이 있다. 본 논문에서는 복시문제와 순환타입 문제를 해결하고 다양한 재귀모듈 패턴을 지원하는 타입시스템을 제안한다.