• 동력기계공학회지
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• 제21권2호
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• pp.5-13
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• 2017

This study has developed an organic/inorganic hybrid solution according to amount of $SiO_2$ polysilicate, and the amount of melamine is constant. The three types of cold rolled steel were evaluated a corrosion resistance properties by using these solutions. $US_3M_3$ and $US_{11}M_3$ solutions were generate a lot of corrosion. $US_7M_3$ solution was excellent in corrosion resistance, regardless of the steel type. The appearance of coating by $US_3M_3$ and $US_{11}M_3$ solutions were bumpy surface, and were a lot of fine defects. $US_7M_3$ solution was made a sophisticated molecular cross-linking structure inside the coating, it was a slick surface. Other characteristics are exhibited the excellent property for all solutions.

• 전기전자학회논문지
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• 제16권3호
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• pp.159-166
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• 2012

In this paper, we designed and implemented the MIMO (Multiple-Input Multiple-Output) antenna for the mobile handset that could be used for multiple services. Simulation results were obtained using SEMCAD X by SPEAG based on the FDTD (Finite Difference Time Domain) Method which showed that S11 values were less than -6 dB (VSWR < 3) for LTE (Long Term Evolution) 700/2300/2500, K-PCS (Korea-Personal Communication Service : 1,750 ~ 1,870 MHz), US-PCS (US-Personal Communication Service : 1,850 ~ 1,990 MHz), Wibro (2,300 ~ 2,390 MHz), Bluetooth (2,400 ~ 2,483 MHz), and US-WiMAX (US-World interoperability for Microwave Access: 2,400 ~ 2,590 MHz) frequency bands. Measured results of the fabricated antenna also showed that it could be used for LTE 700/2300/2500, K-PCS, US-PCS, Wibro, Bluetooth, and US-WiMAX. services.

• 미생물학회지
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• 제54권1호
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• pp.46-52
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• 2018

다환 방향족 탄화수소(polycyclic aromatic hydrocarbon, PAH) 우수 분해균주인 Novosphingobium pentaromativorans US6-1의 dibenzofuran (DBF) 분해경로를 밝히기 위하여 중간대사물질 분석과 전사체 분석을 진행하였다. GC/MS로 중간대사물질을 분석한 결과, 3(2H)-벤조퓨라논이 검출되었는데 이 화합물은 측면 이산소화에 의해 생성된 중간대사산물들의 기본 골격이 되는 물질로써 균주 US6-1에 의한 DBF의 분해가 측면 이산소화로 진행될 가능성을 시사한다. RNA-Seq 분석 결과, 균주 US6-1이 DBF에 노출되었을 때 발현되는 유전자들의 대부분이 lateral dioxygenation과 관련이 있다는 것을 확인하였다. 이상의 결과로부터N. pentaromativorans US6-1에 의해 일어나는 측면 이산소화를통한 DBF 분해경로와 관련 유전자들을 제시하였다.

• 기술혁신학회지
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• 제4권3호
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• pp.311-322
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• 2001

This study is on the decomposition analysis of the IT export of Korea, Japan, and China (toward US IT market) by using log mean Divisia method. The analysis shows that the increase in the Korea-US IT exports is the result of not only the increase in the US's IT imports but also the increase in the US's IT market shares. The increases in the Japan-US IT export have shown to be the result of the increase of US's IT import but the market shares have been decreased. The increase in the China-US IT export is the result of the changes in the market shares, changes in IT import structure. and the IT import increase. In order to increase exports toward US markets, Korea have to continue increasing the market share of communication equipments, secure competitive power toward US IT markets with the decline of Japanese's market shares, and secure technical superiority over rising competitive power of Chinas IT industry.

• Asian-Australasian Journal of Animal Sciences
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• 제2권3호
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• pp.319-321
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• 1989

• KDI Journal of Economic Policy
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• 제46권3호
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• pp.1-23
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• 2024

This study empirically investigates the impact of recent US export controls on China on South Korea's semiconductor exports. We analyze South Korean export data to shed light on the repercussions of US export restrictions on a third country. Our findings reveal a significant decline in Korean semiconductor exports following the October 2022 imposition of US controls. This decline was most pronounced in the memory, discrete devices, and discrete device components subsectors of the semiconductor industry. In addition, we observed a decrease in unit prices, especially for memory semiconductors, pointing to downward pressure on South Korea's high-value-added semiconductor exports. These results provide some evidence of substantial negative impacts of US export controls on South Korea's semiconductor industry, and particularly with regard to its high-tech products.

• Imaging Science in Dentistry
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• 제48권3호
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• pp.153-160
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• 2018

Purpose: This study aimed to assess the reliability of ultrasonography (US) in comparison with cone-beam computed tomography (CBCT) as a tool for monitoring the healing of jaw lesions. Materials and Methods: Twenty-one radiolucent lesions in jaws referred to the Oral Surgery Department at our institution were selected for this study. All lesions underwent CBCT and US examinations. The anteroposterior, superoinferior, and mesiodistal dimensions of the lesions were measured on CBCT and US images before surgery and at 6 months after surgery. The dimensions were compared between the US and CBCT images. Blood-flow velocity around the lesions was measured by color Doppler before surgery and at 1 week and 6 months after surgery to assess the capability of US to show changes in blood-flow velocity around the lesion. Results: Before surgery, there were no significant differences between US and CBCT in the mesiodistal and anteroposterior dimensions, although a significant difference was found in the superoinferior dimension (P<.05). However, at 6 months after surgery, significant differences were found between US and CBCT in all dimensions, and it is likely that the US measurements more accurately reflected the extent of healing. The average blood-flow velocity increased at 1 week after surgery (5.84 cm/s) compared with the velocity before surgery (4 cm/s) (P<.05). Then, at 6 months after surgery, the blood-flow velocity significantly decreased (3.53 cm/s) compared to the velocity measured at 1 week after surgery (P<.05). Conclusion: US with color Doppler was confirmed to be a more efficient tool than CBCT for monitoring bone healing.

• Korean Journal of Radiology
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• 제23권9호
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• pp.866-877
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• 2022

Objective: The optimal imaging approach for evaluating pathological nipple discharge remains unclear. We investigated the value of adding ductography to ultrasound (US) for evaluating pathologic nipple discharge in patients with negative mammography findings. Materials and Methods: From July 2003 to December 2018, 101 women (mean age, 46.3 ± 12.2 years; range, 23-75 years) with pathologic nipple discharge were evaluated using pre-ductography (initial) US, ductography, and post-ductography US. The imaging findings were reviewed retrospectively. The standard reference was surgery (70 patients) or > 2 years of follow-up with US (31 patients). The diagnostic performances of initial US, ductography, and post-ductography US for detecting malignancy were compared using the McNemar's test or a generalized estimating equation. Results: In total, 47 papillomas, 30 other benign lesions, seven high-risk lesions, and 17 malignant lesions were identified as underlying causes of pathologic nipple discharge. Only eight of the 17 malignancies were detected on the initial US, while the remaining nine malignancies were detected by ductography. Among the nine malignancies detected by ductography, eight were detected on post-ductography US and could be localized for US-guided intervention. The sensitivities of ductography (94.1% [16/17]) and post-ductography US (94.1% [16/17]) were significantly higher than those of initial US (47.1% [8/17]; p = 0.027 and 0.013, respectively). The negative predictive value of post-ductography US (96.9% [31/32]) was significantly higher than that of the initial US (83.3% [45/54]; p = 0.006). Specificity was significantly higher for initial US than for ductography and post-ductography US (p = 0.001 for all). Conclusion: The combined use of ductography and US has a high sensitivity for detecting malignancy in patients with pathologic nipple discharge and negative mammography. Ductography findings enable lesion localization on second-look post-ductography US, thus facilitating the selection of optimal treatment plans.

• 융합보안논문지
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• 제16권3_1호
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• pp.27-35
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• 2016

미국이 추진하고 있는 제3차 국방과학기술 상쇄전략에 대하여 그 출현 배경, 상쇄전략에 의하여 추진되는 국방과학기술 분야, 그리고 시사점을 분석하였다. 중국과 소련은 지난 수년간 군사력 현대화를 추진하여 왔으며, 미국과 국방과학기술의 여러 분야에서 수준 격차를 줄여 왔다. 미국은 과거에 누렸던 압도적인 국방과학기술의 우세성이 더 이상 보장받을 수 없다고 판단하고, 경쟁국가와 국방과학기술의 간격을 다시 벌릴 수 있는 제3차 상쇄전략을 추진하게 되었다. 핵심적으로 구상하고 있는 국방과학기술 분야는 인공지능을 응용한 학습기계 기술, 인간과 기계의 협동, 인간과 기계의 전투팀 구성, 로봇, 자율무기 등이다. 제3차 상쇄전략은 상대방 국가가 확보하기 어려운 분야이여야 하고, 중국과 군비경쟁으로 발전되지 말아야 하며, 우방국들과 갈등도 발생하지 않도록 관리되어야 할 것이다. 민간영역의 신기술이 국방영역으로 순조롭게 유입되도록 미 국방획득체계의 개선도 과제이다. 한국도 국방과학기술 분야에 대하여 스마트한 연구개발 전략 수립이 필요하다. 한국은 장차 미국의 3차 상쇄전략 기술 분야 중에서 상호 협력할 수 있는 국방과학기술을 검토하는 것도 요구된다.

• 농업과학연구
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• 제45권4호
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• pp.905-916
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• 2018

The purpose of this study was to analyze factors affecting US beef consumption intention in the future, to identify the causes of US beef import growth and to derive implications and strategies for domestic beef producers. Since the KORUS FTA was signed in 2012, US beef imports in 2017 totaled 379,064 tons, an annual increase of 3.5 percent. US beef imports have been steadily increasing due to cuts in FTA tariffs and changes in consumer preferences. The data used in this study utilized a sample of 3,290 grocery purchasers from the Korea Rural Economic Institute's 2016 Food Consumption Behavior Survey. The analytical method used the Ordered Logit Model to analyze what factors influence a consumer's subjective evaluation. As a result, the major factors affecting US beef consumption intention in the future are price, taste and safety. In particular, it has to do with the recent surge in U.S. imports of good-tasting chilled meat. Because chilled meat does not differentiate the market from Hanwoo beef produced in Korea, it is necessary to have differentiated taste and low price through cost reduction. By age and family group, people aged 30 - 40 years and single-person households are the main consumption group. As a result of this study, it is necessary to establish marketing strategies for producers such as rational pricing, safety, taste promotion, and small-scale sales to extend the demand for Hanwoo beef in the younger generation to enhance the competitiveness of the domestic beef market.