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곡물대탈취: 1973년 미국-소비에트 곡물 거래와 국제 식량 체계의 위기
이동규 ( Lee¸ Dongkyu ) 고려대학교 역사연구소 2022 사총 Vol.105 No.-
본 논문은 1970년대 초반 전 세계적인 식량 위기 과정에서 발생했던 소련의 곡물 대탈취(Great Grain Robbery)라고 불리는 사건에 주목한다. 1973년 소련은 농업보조금이 적용된 가격으로 대략 천만 톤의 곡물을 미국의 곡물 회사로부터 구매한다. 잉여농산물 판매를 통해 닉슨 행정부는 소련과의 관계를 개선하면서 동시에 소련의 농업 부문의 종속성을 강화하려는 의도를 가지고 있었다. 그러나 소련 정부가 다수의 곡물 기업들에게 개별적으로 접근하여 계약을 진행했기 때문에 미국 정부는 대규모의 곡물이 한 번에 판매되는 것을 인지하지 못했다. 미국이 예상했던 것보다 대량의 곡물이 판매되면서, 남북전쟁 이후 가장 높은 곡물가를 기록하게 되었고, 국제 곡물 시장에서의 곡물 가격 역시 급격하게 상승했다. 1972년 농업 생산의 감소에서 시작한 국제적 규모의 식량 위기는 1973년의 미소간 곡물 거래 이후 심화되었다. 본 논문은 곡물 탈취 사건을 통해 1970년대 초의 식량 위기의 단편을 살펴보고, 이를 통해 1960년대에서 1970년대로 이어지는 국제 관계의 변화를 식량이라는 생태학적 주제를 중심으로 살펴본다. This paper focuses on an event called the Great Grain Robbery of 1973, which occurred during the global food crisis of the early 1970s. The USSR purchased approximately 10 million tons of grain subsidized by the US government. The United States initially intended to consume American agricultural surpluses and improve relations with the Soviet Union while at the same time strengthening Soviet dependence on the United States’ agricultural sector. After the grain deal, the United States recorded the highest grain price since the Civil War, and the prices in the international grain market also rose sharply. A food crisis on an international scale, which started with a decline in production in 1972, resulted, deepening after the 1973 grain deal. The purpose of this paper is to examine a part of the food crisis in the early 1970s that arose from the grain deal.
Exciton dynamics in cation-exchanged CdSe/PbSe nanorods: The role of defects
Lee, Sooho,Wang, Yimeng,Liu, Yawei,Lee, Dongkyu,Lee, Kangha,Lee, Doh C.,Lian, Tianquan Elsevier 2017 Chemical physics letters Vol.683 No.-
<P>Cation exchange occurs via defect initiated solid-state diffusion, a process that can lead to defect formations. The effect of such inherent defect formation on carrier dynamics of cation-exchanged heterostructures remains poorly understood. Herein, we report exciton dynamics in type II CdSe/PbSe heterostructure nanorods formed via cation exchange. The majority of electrons in CdSe domains decays in 5 ps due to ultrafast carrier trapping. The defect generated by cation exchange can be healed by annealing the as-synthesized CdSe/PbSe heterostructure nanorods. This study suggests a strategy for improving properties of heteronanostructures prepared by cation exchange for applications in photovoltaics and photocatalysis. (C) 2017 Elsevier B.V. All rights reserved.</P>
Direct Cd-to-Pb Exchange of CdSe Nanorods into PbSe/CdSe Axial Heterojunction Nanorods
Lee, Dongkyu,Kim, Whi Dong,Lee, Seokwon,Bae, Wan Ki,Lee, Sangheon,Lee, Doh C. American Chemical Society 2015 Chemistry of materials Vol.27 No.15
<P>We report synthesis of PbSe nanorods (NRs) and PbSe/CdSe axial heterojunction NRs via direct Cd-to-Pb cation exchange in CdSe NRs. Use of suited ligand–cation combinations enables the cation exchange while keeping the nanomaterial morphology intact. For example, solvation of Cd<SUP>2+</SUP> using oleylamine (OLA) allows for the cation exchange process, which would not be possible by using oleic acid instead of OLA. A mild cation exchange process, such as mixing Pb-oleate and OLA with CdSe NRs at 130 or 150 °C, results in anisotropic replacement of CdSe into PbSe along the ⟨0001⟩ direction of wurtzite CdSe, and a partial conversion leads to the formation of heterostructure NRs containing axial CdSe/PbSe heterojunctions. While the cation exchange proceeds at both tips of CdSe NRs, exchange appears to be faster on (0001̅) planes. Binding energy calculation based on density functional theory reveals that OLA binds strongly to the (0001̅) facet of CdSe NRs, leading to asymmetric cation exchange. This protocol to convert CdSe nanocrystals directly into PbSe broadens the design range of CdSe/PbSe heterojunction nanomaterials potentially with various morphologies because template CdSe nanocrystals can be prepared in different shapes via colloidal synthesis.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/cmatex/2015/cmatex.2015.27.issue-15/acs.chemmater.5b01548/production/images/medium/cm-2015-01548m_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/cm5b01548'>ACS Electronic Supporting Info</A></P>
Jeong, Hyun Woo,Lee, Joo-Won,Kim, Woo Sik,Choe, Sung Sik,Kim, Kyung-Hee,Park, Ho Seon,Shin, Hyun Jung,Lee, Gha Young,Shin, Dongkyu,Lee, Hanjae,Lee, Jun Hee,Choi, Eun Bok,Lee, Hyeon Kyu,Chung, Heekyoun American Diabetes Association 2011 Diabetes Vol.60 No.2
<P><B>OBJECTIVE</B></P><P>Peroxisome proliferator–activated receptor (PPAR)-α/γ dual agonists have been developed to alleviate metabolic disorders. However, several PPARα/γ dual agonists are accompanied with unwanted side effects, including body weight gain, edema, and tissue failure. This study investigated the effects of a novel PPARα/γ dual agonist, CG301269, on metabolic disorders both in vitro and in vivo.</P><P><B>RESEARCH DESIGN AND METHODS</B></P><P>Function of CG301269 as a PPARα/γ dual agonist was assessed in vitro by luciferase reporter assay, mammalian one-hybrid assay, and analyses of PPAR target genes. In vitro profiles on fatty acid oxidation and inflammatory responses were acquired by fatty acid oxidation assay and quantitative (q)RT-PCR of proinflammatory genes. In vivo effect of CG301269 was examined in <I>db/db</I> mice. Total body weight and various tissue weights were measured, and hepatic lipid profiles were analyzed. Systemic glucose and insulin tolerance were measured, and the in vivo effect of CG301269 on metabolic genes and proinflammatory genes was examined by qRT-PCR.</P><P><B>RESULTS</B></P><P>CG301269 selectively stimulated the transcriptional activities of PPARα and PPARγ. CG301269 enhanced fatty acid oxidation in vitro and ameliorated insulin resistance and hyperlipidemia in vivo. In <I>db/db</I> mice, CG301269 reduced inflammatory responses and fatty liver, without body weight gain.</P><P><B>CONCLUSIONS</B></P><P>We demonstrate that CG301269 exhibits beneficial effects on glucose and lipid metabolism by simultaneous activation of both PPARα and PPARγ. Our data suggest that CG301269 would be a potential lead compound against obesity and related metabolic disorders.</P>
Wang, Nianfang,Koh, Sungjun,Jeong, Byeong Guk,Lee, Dongkyu,Kim, Whi Dong,Park, Kyoungwon,Nam, Min Ki,Lee, Kangha,Kim, Yewon,Lee, Baek-Hee,Lee, Kangtaek,Bae, Wan Ki,Lee, Doh C IOP 2017 Nanotechnology Vol.28 No.18
<P>We present facile synthesis of bright CdS/CdSe/CdS@SiO<SUB>2</SUB> nanoparticles with 72% of quantum yields (QYs) retaining ca 80% of the original QYs. The main innovative point is the utilization of the highly luminescent CdS/CdSe/CdS seed/spherical quantum well/shell (SQW) as silica coating seeds. The significance of inorganic semiconductor shell passivation and structure design of quantum dots (QDs) for obtaining bright QD@SiO<SUB>2</SUB> is demonstrated by applying silica encapsulation via reverse microemulsion method to three kinds of QDs with different structure: CdSe core and 2 nm CdS shell (CdSe/CdS-thin); CdSe core and 6 nm CdS shell (CdSe/CdS-thick); and CdS core, CdSe intermediate shell and 5 nm CdS outer shell (CdS/CdSe/CdS-SQW). Silica encapsulation inevitably results in lower photoluminescence quantum yield (PL QY) than pristine QDs due to formation of surface defects. However, the retaining ratio of pristine QY is different in the three silica coated samples; for example, CdSe/CdS-thin/SiO<SUB>2</SUB> shows the lowest retaining ratio (36%) while the retaining ratio of pristine PL QY in CdSe/CdS-thick/SiO<SUB>2</SUB> and SQW/SiO<SUB>2</SUB> is over 80% and SQW/SiO<SUB>2</SUB> shows the highest resulting PL QY. Thick outermost CdS shell isolates the excitons from the defects at surface, making PL QY relatively insensitive to silica encapsulation. The bright SiO<SUB>2</SUB>-coated SQW sample shows robustness against harsh conditions, such as acid etching and thermal annealing. The high luminescence and long-term stability highlights the potential of using the SQW/SiO<SUB>2</SUB> nanoparticles in bio-labeling or display applications.</P>
Lee, Dongkyu,Shin, Soomi,Doan, Quoc Hoan Elsevier 2018 Construction and Building Materials Vol.186 No.-
<P><B>Abstract</B></P> <P>In this article, a simple and robust real-time decision framework to determine the optimum angle of the outrigger satisfying structural safety of tall buildings is proposed to evaluate a general-purpose prototype of steel outrigger geometry. The methodology is applied to sets of the ratio of height to width generally describing non-scaled outrigger space. To achieve the general-purpose prototype of outrigger geometry, the optimal angles for three sets of height to width of a given outrigger space are examined with respect to displacement capacities using a typical Maxwell-Mohr method, and in the optimal angle, the least horizontal and vertical displacements occur when the quantity is standardized. When the width and height of the outrigger is confirmed in a given tall building, the shape of outrigger, with its good structural performance, can be reflected in the outrigger member position design for general purposes, allowing pre-calculations of the optimal angle and a reduction in quantity. Numerical examples verify the validity and efficiency of the present assessment method to decide optimal angle and position of outrigger truss members with respect to general-purpose prototype.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Computer-aided automatic decision framework assesses general-purpose prototypes of outrigger. </LI> <LI> Steel material outrigger evaluates interactions between material characteristics and structural system. </LI> <LI> Optimal connectivity of outrigger members under structural safety is evaluated using Maxwell-Mohr method. </LI> </UL> </P>
Lee, Taehyun,Sim, Dongkyu,Seo, Bongsung,Lee, Chungyong IEEE 2019 IEEE Transactions on Vehicular Technology VT Vol.68 No.1
<P>This paper proposes a channel estimation scheme for the filter-bank multicarrier systems with quadrature amplitude modulation (FBMC-QAM). Under frequency selective channels, the adjacent data symbols cause interference to the pilot symbols in FBMC-QAM systems and degrade the performance of the channel estimation. To handle this problem, we analyze the interference of the pilot symbols in an oversampled frequency domain before the receiver filtering process. Exploiting the interference analysis, we propose a pilot symbol configuration and condition of filter coefficients to cancel the inter-carrier interference. Moreover, we apply a time domain data symbol precoding to eliminate inter-symbol interference. The simulation results show that the proposed scheme outperforms conventional channel estimation schemes.</P>