시멘트 혼합재의 입도분포와 페이스트 유동특성

유동우,최현국,이승헌,이세진,Yoo, Dong-Woo,Choi, Hyun-Kook,Lee, Seung-Heun,Lee, Se-Jin 한국건설순환자원학회 2011 한국건설순환자원학회지 Vol.6 No.2

본 연구에서는 현재 시멘트 콘크리트 혼합재로서 널리 사용되고 있는 고로수쇄 슬래그와 애쉬의 페이스트 유동특성을 파악하였다. 그 방법으로 혼합재 단독을 사용한 페이스트의 유동특성을 파악하여, 아래와 같은 결론을 얻을 수 있었다. 혼합재 단독의 페이스트 유동특성을 시험하기 위하여, 3종류의 분쇄기를 사용하여 3가지 입도로 분쇄된 분말을 제조하였다. 이 분말을 Rosin-Rammler 분포식을 사용하여 얻은 계수 n 값과 De 값을 유동특성과 비교 분석한 결과에서, 일반적으로 같은 입경 크기 일 때 Ash 분말이 Slag 분말보다 소성점도 및 항복응력이 높았으며, 또한 동일 n 값에서 Ash 분말이 Slag 분말 보다 비교적 높은 소성점도와 항복응력을 나타내었으나, 입도분포 폭의 변화에는 Slag 분말이 Ash 분말 보다 민감한 유동특성의 변화 경향을 나타내었다. This study examined rheological properties of blast furnace slag and ash paste that are widely used as cement concrete for mineral admixture in current. In that way rheological properties of the paste of mineral admixture only was examined. The result of this study were as follow: In order to analyze that the rheological properties of the mineral admixture only, fine particles were produced with grinding machine to 3 particle sizes. These powders in general from the result of comparison with and analysis of rheological properties and the coefficient n and De values. The result that ash powder was higher in plastic viscosity and yield stress than Slag powder, and with the same n value, ash powder showed higher plastic viscosity and yield stress than Slag powder. But Slag powder in particle size distribution showed a sensitive tendency on changing in rheological properties.

상대 차량 효용 추정 기반 게임이론을 활용한 자율주행차의 차선 변경 알고리즘 개발

유동우,김주희,안창선 한국자동차공학회 2024 한국 자동차공학회논문집 Vol.32 No.1

This paper presents an interaction algorithm that can be used in lane change scenarios through a game theory based on estimated opposing vehicle utility. General game theory-based interaction algorithms are valuable in implementing interaction mechanisms that consider the utility of related vehicles. However, they may become inefficient due to uncertainties of the utilities of opposing vehicles. The primary concept behind estimating utility is defining it as a function of achieving driving goals and ensuring safety, which are universal considerations in changing lanes. Weights for each objective in the utility function are determined based on the driver’s driving characteristics. The proposed algorithm estimates opposing vehicle utility by adjusting driving characteristics through driving patterns. Finally, the Stackelberg game, which is grounded in updated utility, offers an optimal lane change strategy after considering the opponent’s real-time actions. The proposed algorithm was then validated, and could provide a beneficial strategy based on safety, traffic flow, and individual driving preferences.

수중부 하부 구조의 보수 보강

유동우 한국콘크리트학회 2001 콘크리트학회지 Vol.13 No.2

Is the British Colonization better than that of the French?: A Study of Vanuatu

유동우 경제사학회 2022 經濟史學 Vol.46 No.3

Comparative studies have suggested that British colonization is more beneficial than that of France and other colonizers. It is argued that British cultures and institutions contributed to stable politics and robust economic development of its colonies. However, evidence is still inconclusive because a controlled experiment is very difficult in social science. Vanuatu – a Pacific island – provides an excellent setting for reconsidering the argument. Britain and France established a joint government, the British government, and the French government, which lasted from 1906 until 1980, in the same territory. Local people could choose whether to be tried under the British common law or the French civil law. Nationals of one country could set up corporations under the laws of the other. The case of Vanuatu suggests that political perspectives are in favor of Britain, but economic perspectives are in favor of France. The French-dominated areas have been more developed than the British-dominated areas. The major British trading company established a company under the French law and a certain number of British planters registered themselves in the French residency to attain the benefits of French economic policies.

중간대뇌동맥과 두개외 속목동맥의 급성 일렬폐색에 의한 초급성 뇌경색 환자에서 성공적인 혈관내 물리적 혈전제거치료 성공 증례

유동우,이시백,한시령,박형은,배대웅,구자성,김범수 대한뇌졸중학회 2011 Journal of stroke Vol.13 No.3

Previous studies have shown that patients with tandem occlusions involving extracranial internal carotid artery (ICA) and middle cerebral artery (MCA) have lower likelihood of recanalization by standard intravenous thrombolytic therapy. A 70-years-old man with a history of hypertension was admitted because of left hemiplegia and drowsiness which developed 47 minutes ago. On neurologic examination, he was drowsy and showed neglect syndrome as well as left hemiplegia. Brain CT angiography showed tandem occlusions at right extracranial ICA and proximal MCA. The administration of intravenous (IV) tissue plasminogen activator (tPA) did not improve his symptoms. We performed angioplasty and stenting for proximal ICA occlusion followed by mechanical thrombolysis for MCA occlusion. After the endovascular treatment, the MCA was recanalized and the patient recovered to show only mild left side weakness. This case shows successful treatment of hyperacute ischemic infarction from tendem occlusion of right MCA and proximal ICA with endovascular treatment following IV tPA thrombolysis. (Korean J Stroke 2011;13:147-151)

『사라지는 것은 아쉬움을 남긴다』 (김두얼 지음) 생각의힘, 2020년

유동우 경제사학회 2021 經濟史學 Vol.45 No.1

중증 백질변성 환자에서 대뇌부챗살 급성열공경색 후 발생한 의식저하

유동우,이영현,권세윤,손영민,김범생,조아현 대한신경과학회 2012 대한신경과학회지 Vol.30 No.4

With an increasing proportion of the elderly, dementia due to severe cerebral white matter change is frequently observed. Because these patients cannot express their symptoms effectively, the recognition of stroke can be delayed. In addition, clinical characteristics of their stroke might be different. We reported on three patients with severe leukoaraiosis, who exhibited altered consciousness after acute lacunar infarction in the corona radiata. This clinico-radiological discrepancy may have resulted from different susceptibility to ischemia in patients with severe white matter change.

『대번영의 조건 : 모두에게 좋은 자본주의란 무엇인가』 : Edmund Phelps 지음, 이창근 · 홍대운 옮김

유동우 경제사학회 2017 經濟史學 Vol.41 No.3

초미분말 애시를 혼합한 시멘트의 물성

유동우,변승호,송종택 한국세라믹학회 2007 한국세라믹학회지 Vol.44 No.9

Efects of ultrafinely ground ash on the rheological properties of cement paste were investigated. Also compressive strengthasincluded for comparison. According to the results of ultrafine ash blended cement paste in the lower W/B ratio, the fluidity were high,and the setting time was a little retarded. And the compressive strength of ultrafine ash blended mortar was increased in the long term.In the case of hardened cement paste at 28 days, Ca(OH)2 contents was decreased in order of control, ultrafine ash, silica fume blendedcement due to diference of the pozzolanic reaction.

Effects of D-Serine and MK-801 on Neuropathic Pain and Functional Recovery in a Rat Model of Spinal Cord Injury

유동우,문슬아,김상우,조대철,김치헌,한인보,이수범,이상우,김경태 대한척추신경외과학회 2022 Neurospine Vol.19 No.3

Objective: Neuropathic pain is a common secondary complication of spinal cord injury (SCI). N-methyl-D-aspartate (NMDA) receptor activation is critical for hypersensitivity in neuropathic pain. This activation requires the binding of both glutamate and the D-serine co-agonist to the NMDA glycine site. We evaluated the effects of D-serine on neuropathic pain after SCI and explored the underlying molecular mechanisms. Methods: Anesthetized rats underwent T9 spinal cord contusion (130 kdyn). D-serine (500 and 1,000 mg/kg) and MK-801 hydrogen maleate (2.0 mg/kg) were injected daily for 2 weeks, starting the day after SCI. Functional outcomes were assessed according to the Basso, Beattie, and Bresnahan scale, while histological outcomes were evaluated based on lesion volume and spared tissue area. Mechanical allodynia and thermal hyperalgesia were evaluated by measuring the withdrawal threshold of a von Frey filament and hot/cold plate latency. Western blotting was performed to determine the expression levels of Trpv1, Nav1.9, calcitonin gene-related peptide (CGRP), and β-actin in damaged tissue. Results: The withdrawal threshold values and latency of the D-serine group were significantly lower than those of the noninjection group. The MK-801 group showed higher threshold values and latencies than the other groups. Western blotting showed increased Nav1.9 and Trpv1 levels and lower CGRP levels in the D-serine group, whereas the MK-801 group showed the opposite results. Conclusion: D-serine increases neuropathic pain after traumatic SCI by mediating the NMDA receptor. NMDA receptor antagonists alleviate neuropathic pain after traumatic SCI.