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.

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>

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>

Evaluating Topological Optimized Layout of Building Structures by Using Nodal Material Density Based Bilinear Interpolation

Lee, Dongkyu,Lee, Jaehong,Lee, Kihak,Ahn, Namshik Informa UK (TaylorFrancis) 2014 JOURNAL OF ASIAN ARCHITECTURE AND BUILDING ENGINEE Vol.13 No.2

Solar heating and cooling system with prediction of solar radiation applying deep learning analysis

Dongkyu Lee(이동규),Hyunmin Nam(남현민),Eunju Lee(이은주),Kinam Kang(강기남),Byoungdoo Lee(이병두) 한국신재생에너지학회 2017 한국신재생에너지학회 학술대회논문집 Vol.2017 No.9

흉부 단순촬영 영상을 이용한 척추측만증 조기 진단 모델 개발

이승아(Seung-Ah Lee),최선(Seon Choe),장미영(Miyoung Jang),이동규(Dongkyu Lee),양수진(Sujin Yang),이선호(Sun-Ho Lee),최현수(Hyun-soo Choi),이준구(June-Goo Lee) 한국정보과학회 2022 한국정보과학회 학술발표논문집 Vol.2022 No.06

A Newly Identified CG301269 Improves Lipid and Glucose Metabolism Without Body Weight Gain Through Activation of Peroxisome Proliferator–Activated Receptor α and γ

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>

Highly luminescent silica-coated CdS/CdSe/CdS nanoparticles with strong chemical robustness and excellent thermal stability

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>

Direct cation exchange of CdSe nanocrystals into ZnSe enabled by controlled binding between guest cations and organic ligands

Lee, Sooho,Yoon, Da-Eun,Kim, Dahin,Shin, Do Joong,Jeong, Byeong Guk,Lee, Dongkyu,Lim, Jaehoon,Bae, Wan Ki,Lim, Hyung-Kyu,Lee, Doh C. The Royal Society of Chemistry 2019 Nanoscale Vol.11 No.32

<P>Zn chalcogenides are suitable candidates for blue-emitting fluorophores in light-emitting devices. In particular, the efforts to grow ZnSe nanocrystals (NCs) with fine control over size and shape <I>via</I> bottom-up approaches have faced challenges because of the slow decomposition of Zn precursors. In this study, we report direct cation exchange from CdSe NCs to ZnSe. Absorption spectroscopy and density functional theory (DFT) analysis reveal that the reactivity of cation exchange depends on the degree of complexation between organic ligands and Zn halides. We controlled the binding strength of Zn complexes by changing the organic ligands and halogen species that bind with Zn. Appropriate binding strength allows for the release of Zn ions and their facile incorporation into CdSe seed NCs. Under our experimental conditions, trioctylphosphine oxide (TOPO)-ZnI2 drives the efficient cation exchange reaction whereas TOPO-ZnCl2 induces no cation exchange of CdSe NCs. In addition, functional groups vary the binding strength between Zn and ligands. Oleylamine (OLAm)-ZnI2, which has a weaker ligand-ZnI2 binding than TOPO-ZnI2, breaks down the original morphologies of host CdSe NCs due to the very fast exchange rate. On the other hand, the TOPO-ZnI2 complex induces a mild exchange rate, leading to transformation into various morphologies such as CdSe nanorods (NRs) and nanoplatelets (NPLs) into CdSe/ZnSe heterostructures inaccessible <I>via</I> other synthesis methods. The incorporation of Zn into various morphologies of CdSe results in tunable optical transitions in blue-UV regions. The synthesis of heterostructured NCs in an elongated morphology is possible, opening opportunities in photocatalysis, light emitting diodes, and luminescent solar concentrators.</P>

Effect of Action Observational Training on Gait in People with Stroke

Lee, JongSu,Kim, YoungMi,Lee, DongKyu 대한물리치료학회 2020 대한물리치료학회지 Vol.32 No.1

Purpose: This study examined the effects of action observational training to improve the gait function for patients with stroke. Methods: The participants were divided into two groups: right hemiplegia group (n=12) and left hemiplegia group (n=12). All groups received conventional therapy for five sessions for 30 minutes, each for three weeks. Left and right hemiplegia group practiced additional action observational training for five sessions for 20 minutes each for three weeks. They participated in three weeks of action observational training coupled with immediate physical practice (intervention), followed by a final assessment. The duration of each action observation video sequence was 10 minutes, followed immediately by practice of the observed motor skill (10 minutes). The gait velocity, cadence, swing time, step length, and BOS (base of support) were examined using the GAITRite system. Results: The results of this study showed significant improvement in the gait function. The outcomes of the gait abilities from gait velocity, cadence, swing time, step length of the affected side, and BOS (base of support) were improved significantly in the right hemiplegia group (p<0.05). In the left hemiplegia group, there was no significant improvement in the gait velocity, cadence, and BOS except for the swing time and step length of the affected side. The left and right group comparisons between the groups were not significant (p<0.05). Conclusion: Action observation training improves the gait function. These results suggest that action observational training is feasible and suitable for stroke patients.