High-Angle Tilt Boundary Graphene Domain Recrystallized from Mobile Hot-Wire-Assisted Chemical Vapor Deposition System

Lee, Jinsup,Baek, Jinwook,Ryu, Gyeong Hee,Lee, Mi Jin,Oh, Seran,Hong, Seul Ki,Kim, Bo-Hyun,Lee, Seok-Hee,Cho, Byung Jin,Lee, Zonghoon,Jeon, Seokwoo American Chemical Society 2014 NANO LETTERS Vol.14 No.8

<P>Crystallization of materials has attracted research interest for a long time, and its mechanisms in three-dimensional materials have been well studied. However, crystallization of two-dimensional (2D) materials is yet to be challenged. Clarifying the dynamics underlying growth of 2D materials will provide the insight for the potential route to synthesize large and highly crystallized 2D domains with low defects. Here, we present the growth dynamics and recrystallization of 2D material graphene under a mobile hot-wire assisted chemical vapor deposition (MHW-CVD) system. Under local but sequential heating by MHW-CVD system, the initial nucleation of nanocrystalline graphenes, which was not extended into the growth stage due to the insufficient thermal energy, took a recrystallization and converted into a grand single crystal domain. During this process, the stitching-like healing of graphene was also observed. The local but sequential endowing thermal energy to nanocrystalline graphenes enabled us to simultaneously reveal the recrystallization and healing dynamics in graphene growth, which suggests an alternative route to synthesize a highly crystalline and large domain size graphene. Also, this recrystallization and healing of 2D nanocrystalline graphenes offers an interesting insight on the growth mechanism of 2D materials.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2014/nalefd.2014.14.issue-8/nl5012323/production/images/medium/nl-2014-012323_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl5012323'>ACS Electronic Supporting Info</A></P>

Design and synthesis of pyrrolidine-containing sphingomimetics

Lee, Seokwoo,Lee, Sukjin,Park, Hyen Joo,Lee, Sang Kook,Kim, Sanghee Royal Society of Chemistry 2011 Organic & Biomolecular Chemistry Vol.9 No.12

<P>Based on the structures of natural sphingolipids, we designed heterocyclic sphingoid base mimetics in which the conformational restriction is introduced by incorporation of a pyrrolidine moiety between the 2-amino group and the C-4 carbon atom of the sphingoid base. Our synthesis features a regioselective nucleophilic ring opening of a cyclic sulfate with cyanide and subsequent manipulation of the cyanide group. During the course of synthesis, Staudinger-type reductive cyclization of 1,3-azido carboxylic acid and 1,4-azido alcohol offers a direct route to the five-membered pyrrolidone and pyrrolidine products. The preliminary biological evaluation indicates that the designed pyrrolidine analog is biologically active and its cytotoxic effect is associated with the induction of apoptosis.</P> <P>Graphic Abstract</P><P>This paper describes conformationally constrained sphingomimetics in which a pyrrolidine moiety is incorporated between the 2-amino group and the C-4 carbon atom of the sphingoid base. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c1ob05324h'> </P>

A Study on Field Emission Characteristics of Planar Graphene Layers Obtained from a Highly Oriented Pyrolyzed Graphite Block

Lee, SeokWoo,Lee, Seung S,Yang, Eui-Hyeok Springer 2009 NANOSCALE RESEARCH LETTERS Vol.4 No.10

<P>This paper describes an experimental study on field emission characteristics of individual graphene layers for vacuum nanoelectronics. Graphene layers were prepared by mechanical exfoliation from a highly oriented pyrolyzed graphite block and placed on an insulating substrate, with the resulting field emission behavior investigated using a nanomanipulator operating inside a scanning electron microscope. A pair of tungsten tips controlled by the nanomanipulator enabled electric connection with the graphene layers without postfabrication. The maximum emitted current from the graphene layers was 170 nA and the turn-on voltage was 12.1 V.</P>

Versatile Carbon Hybrid Films Composed of Vertical Carbon Nanotubes Grown on Mechanically Compliant Graphene Films

Lee, Duck Hyun,Kim, Ji Eun,Han, Tae Hee,Hwang, Jae Won,Jeon, Seokwoo,Choi, Sung-Yool,Hong, Soon Hyung,Lee, Won Jong,Ruoff, Rodney S.,Kim, Sang Ouk WILEY-VCH Verlag 2010 Advanced Materials Vol.22 No.11

<B>Graphic Abstract</B> <P>A hybrid system with vertical carbon nanotubes (CNTs) grown on reduced graphene films composed of overlapping and reduced graphene oxide platelets is reported. Such carbon hybrid films have excellent flexibility and stretchability (see image), can be readily transferred to any substrate including nonplanar surfaces, and were found to have Ohmic electrical contacts throughout all junctions in the CNT/metal-catalyst/graphene-film system. <img src='wiley_img_2010/09359648-2010-22-11-ADMA200903063-content.gif' alt='wiley_img_2010/09359648-2010-22-11-ADMA200903063-content'> </P>

Expression of Endothelin-1 and Its Receptors in Cisplatin-Induced Acute Renal Failure in Mice

Seokwoo Lee,Dowhan Ahn 대한생리학회-대한약리학회 2008 The Korean Journal of Physiology & Pharmacology Vol.12 No.4

Endothelin-1 (ET-1) is unequivocally elevated in the kidney with ischemic acute renal failure (ARF), whereas ET receptors (ET_AR and ET_BR) are variably expressed. Although renal functional and structural changes are similar between ischemic and nephrotoxic ARF, there are few reports on the alteration in the ET system in nephrotoxic ARF. This study was, therefore, undertaken to investigate changes in renal expression of ET-1 and its receptors in nephrotoxic ARF induced by cisplatin. Mice were intraperitoneally injected with 16 mg of cisplatin/kg at a single dose, and the expression of mRNA and protein was then quantified by real-time RT-PCR and Western blot, respectively. Immuno</SUB>histochemistry was conducted for localization. Three days after treatment, ET-1 transcript in cisplatin- treated mice was thirteen times higher than that in controls, whereas ET-1 peptide was increased by 1.5-fold. Cisplatin caused a 2-fold increase in the levels of ET_AR mRNA and protein. Most of the increased immunoreactive ET-1 and ET_AR were localized in damaged tubules. Neither the expression of ET_BR mRNA nor the abundance and immunoreactive level of ET_BR protein were changed. The findings suggest that the individual components of the renal ET system are differentially regulated in cisplatin-induced nephrotoxic ARF.

The complex legal status of the Current Fishing Pattern Zone in the East China Sea

Lee, Seokwoo,Park, Young Kil,Park, Hansan Elsevier Science Ldt 2017 Marine policy Vol.81 No.-

<P><B>Abstract</B></P> <P>The purpose of this article is to analyze the legal status of fisheries in the East China Sea (ECS) pursuant to these fisheries agreements, focusing on the legal issues of the Current Fishing Pattern Zone (CFPZ) which is provided for in the Fisheries Agreement between Korea and China. The CFPZ is a zone or area in which Korean and Chinese fishing patterns that existed before the agreement are respected. Although the legal status of fisheries in the CFPZ appears to be very simple, it is in fact very complex due to the overlapping jurisdictions of Korea, China and Japan. Therefore, the fisheries regime is rather vulnerable with the possibility of increasing legal conflicts. However, it is noteworthy that fisheries conflicts come up rarely in these relevant waters. This article explores the bilateral fisheries agreements and EEZ laws of the respective states, and thereafter deals with the legal issues that arise in the execution of these agreements regarding the area of overlapping waters.</P>

Scalable Exfoliation Process for Highly Soluble Boron Nitride Nanoplatelets by Hydroxide-Assisted Ball Milling

Lee, Dongju,Lee, Bin,Park, Kwang Hyun,Ryu, Ho Jin,Jeon, Seokwoo,Hong, Soon Hyung American Chemical Society 2015 NANO LETTERS Vol.15 No.2

<P>The scalable preparation of two-dimensional hexagonal boron nitride (h-BN) is essential for practical applications. Despite intense research in this area, high-yield production of two-dimensional h-BN with large-size and high solubility remains a key challenge. In the present work, we propose a scalable exfoliation process for hydroxyl-functionalized BN nanoplatelets (OH-BNNPs) by a simple ball milling of BN powders in the presence of sodium hydroxide via the synergetic effect of chemical peeling and mechanical shear forces. The hydroxide-assisted ball milling process results in relatively large flakes with an average size of 1.5 μm with little damage to the in-plane structure of the OH-BNNP and high yields of 18%. The resultant OH-BNNP samples can be redispersed in various solvents and form stable dispersions that can be used for multiple purposes. The incorporation of the BNNPs into the polyethylene matrix effectively enhanced the barrier properties of the polyethylene due to increased tortuosity of the diffusion path of the gas molecules. Hydroxide-assisted ball milling process can thus provide simple and efficient approaches to scalable preparation of large-size and highly soluble BNNPs. Moreover, this exfoliation process is not only easily scalable but also applicable to other layered materials.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2015/nalefd.2015.15.issue-2/nl504397h/production/images/medium/nl-2014-04397h_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl504397h'>ACS Electronic Supporting Info</A></P>

The Case concerning Whaling in the Antarctic (Australia v. Japan; New Zealand intervening)

Seokwoo Lee(이석우) 인하대학교 법학연구소 2013 法學硏究 Vol.16 No.3

1946년 12월 포경의 남용으로부터 고래를 보호하기 위해 포경규제에 관한 국제협약(International Convention for the Regulation of Whaling: ICRW)이 체결되었다. 이 협약 제8조는 당사국이 일정한 조건에 따라 과학적 연구를 목적으로 하는 자국민의 포경을 특별허가 할 수 있도록 규정하고 있다. 그런데 ICRW 제3조를 근거로 설립된 국제포경위원회(International Whaling Commission, IWC)는 1980년대 이후 무분별한 포경으로부터 고래를 보호하기 위해 포경에 대한 규제를 강화하기 시작했다. 즉, IWC는 1982년 ICRW의 중요한 부속문서인 명세서(Schedule) 제10항에 (e)를 추가해서 1985/86년 이후 모든 종류의 고래에 대한 상업적 목적의 포경을 금지하였다. 그리고 IWC는 1994년 명세서 제7항에 (b)를 추가하여 남대양 서식지(Southern Ocean Sanctuary)에서의 상업적 포경을 금지하였다. 그 동안 여러 국제기구 회의와 외교적 경로를 통해 일본의 포경행위를 지속적으로 비난하며 중단을 요구해 온 호주는 2010년 5월 31일 포경에 관한 국제적 의무를 위반했다며 일본을 국제사법재판소(ICJ)에 제소하였다. 일본정부는 IWC의 포경 규제강화 이후에도 계속해서 연구목적이라는 구실 하에 민간 어선이 일본 정부의 특별허가를 받아 포경을 할 수 있도록 하는 고래연구프로그램(JARPA II)을 실시해 왔다. 호주는 JARPA II에 따라 일본 어선이 대량의 포경을 하도록 하는 것은 곧 일본이 ICRW상 당사국의 의무를 위반한 것이라고 주장하였다. 본 논문은 협약 제8조를 둘러싼 호주와 일본간의 법리 공방을 중심으로, ICJ에서의 재판결과에 상관없이 향후 IWC 체제의 유지 차제가 부정적이라는 함의를 도출하고 있다. The Case Concerning Whaling in the Antarctic is primarily based on a dispute over the interpretation of the International Convention for the Regulation of Whaling (ICRW). Article VIII provides that “any Contracting Government may grant to any of its nationals a special permit authorizing that national to kill, take and treat whales for purposes of scientific research . . . .” (emphasis added). Utilizing this exception, Japan announced the Japanese Whale Research Program under Special Permit in the Antarctic (JARPA) in the 1987/88 season. Japan commenced the Second Phase of the Japanese Whale Research Program under Special Permit in the Antarctic (JARPA II) during the 2005/6 season. The stated objectives of JARPA II include monitoring the Antarctic ecosystem, modeling competition among whale species, clarifying changes in stock structure, and improving the management of minke whale stocks. After research is conducted, meat from harvested whales is sold for consumption and profits are used to support the Institute for Cetacean Research. On 31 May 2010, Australia instituted proceedings against Japan in the ICJ. Australia filed its memorial on May 9, 2011, and Japan filed a counter-memorial on March 9, 2012. On 20 November 2012, New Zealand filed a Declaration of Intervention in the Registry, and the Court granted permission to intervene on 6 February 2013. Australia claims that Japan’s large scale whaling under JARPA II violates its obligations under the ICRW, as well as its other international obligations for the preservation of marine mammals and marine environment under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) and the Convention on Biological Diversity (CBD). Japan however argues that the Court lacks jurisdiction over Australia’s claims, and that, as a result, New Zealand’s application to intervene lapses. In the alternative, Japan argues that Australia’s claims should be rejected because the whaling activities are conducted for the purposes of scientific research, which is permitted under the ICRW. Australia counters that Japan is engaging in commercial whaling under the guise of “research.” A public hearing was held from on 26 June to 16 July 2013. The Court’s judgment will be rendered at a public sitting but is not expected for several months. This is the first time for Japan to appear as a party to a dispute at the ICJ. For Australia, it is the first time since the 1973 Nuclear Test case for the country to institute proceedings; it last appeared in the ICJ as the Respondent in the East Timor case which began in 1991. If the judgment is unfavorable to Japan, the country might withdraw from the IWC. In the past, Japan has threatened to do so and form an alternative ? and presumably more whaling-friendly ? organization. Such actions will probably initiate a domino effect among other pro-whaling countries. Alternatively, if the judgment favors Japan, the IWC may regain credibility among pro-whaling countries that feel isolated due to the organization’s increasingly conservationist stance. In addition, such a decision may encourage anti-whaling countries to be more flexible in their stance against whaling.

Wearable Textile Battery Rechargeable by Solar Energy

Lee, Yong-Hee,Kim, Joo-Seong,Noh, Jonghyeon,Lee, Inhwa,Kim, Hyeong Jun,Choi, Sunghun,Seo, Jeongmin,Jeon, Seokwoo,Kim, Taek-Soo,Lee, Jung-Yong,Choi, Jang Wook American Chemical Society 2013 Nano letters Vol.13 No.11

<P>Wearable electronics represent a significant paradigm shift in consumer electronics since they eliminate the necessity for separate carriage of devices. In particular, integration of flexible electronic devices with clothes, glasses, watches, and skin will bring new opportunities beyond what can be imagined by current inflexible counterparts. Although considerable progresses have been seen for wearable electronics, lithium rechargeable batteries, the power sources of the devices, do not keep pace with such progresses due to tenuous mechanical stabilities, causing them to remain as the limiting elements in the entire technology. Herein, we revisit the key components of the battery (current collector, binder, and separator) and replace them with the materials that support robust mechanical endurance of the battery. The final full-cells in the forms of clothes and watchstraps exhibited comparable electrochemical performance to those of conventional metal foil-based cells even under severe folding–unfolding motions simulating actual wearing conditions. Furthermore, the wearable textile battery was integrated with flexible and lightweight solar cells on the battery pouch to enable convenient solar-charging capabilities.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2013/nalefd.2013.13.issue-11/nl403860k/production/images/medium/nl-2013-03860k_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl403860k'>ACS Electronic Supporting Info</A></P>

Asymmetric Total Synthesis of Lepadiformine C Using Memory of Chirality in an Intramolecular Ester Enolate Michael Addition

Lee, Seokwoo,Bae, Minsik,In, Jinkyung,Kim, Jae Hyun,Kim, Sanghee American Chemical Society 2017 ORGANIC LETTERS Vol.19 No.1

<P>The asymmetric synthesis of lepadiformine C was achieved using D-proline as the only chiral source. The synthetic strategy features the use of the principle of 'memory of chirality' in an intramolecular Michael addition to construct the bicyclic intermediate without the aid of external chiral sources. A brief mechanistic rationale is presented to account for the stereochemical outcome.</P>