• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 춘계학술대회 및 창립 30주년 심포지엄(논문집)
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• pp.259-264
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• 2006

본 연구는 정기선해운영업을 중심으로 해운산업에서의 전자상거래 활용 및 성과에 영향을 미치는 요인들을 도출한 후, 도출된 영향요인들과 전자상거래 활용수준 및 성과간에 어떠한 인과관계가 있는지를 검증하고자 하였다. 이를 위해 우리나라 해운기업들의 내부환경변수인 해운기업특성과 외부환경변수인 해운환경특성이 전자상거래 활용수준에 어떠한 영향을 미치는지와 우리나라 해운기업들의 전자상거래 활용수준이 전자상거래 활용성과에 어떠한 영향을 미치는지의 2단계 연구모형을 구조방정식모델을 통해 실증분석하였다.

• 동의생리병리학회지
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• 제25권5호
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• pp.881-886
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• 2011

AMPA receptor (AMPAR)s are heterotetrameric structures made up from 4 units (GluR1-4) and are thought to underlie perception of persistent inflammatory pain. Complete Freund's adjuvant (CFA)-evoked inflammation induces synaptic GluR2 internalization, which is initiated by GluR2 phosphorylation, in dorsal horn neurons during the maintenance of CFA-induced hypersensitivity. The present study investigated whether electroacupuncture (EA) stimulation has any effect on GluR2 trafficking by using immunoblot and immunohistochemistry. We examined that CFA-induced dorsal horn GluR2 internalization was attenuated by EA treatment. EA treatment could also decrease the level of pGluR2 regardless of whether CFA injection was administrated or not. In addition, previous studies suggest that microglial cells are increased without morphological change in CFA injected animal. In our study, increases in microglial cells in CFA group were observed, whereas EA with or without CFA-injected group showed similar aspects with normal group. In conclusion, our results indicate that EA might blunt CFA-evoked inflammation by coordinating mechanisms at the upstream step of neuron activation and GluR2 phosphorylation.

• 수면정신생리
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• 제3권2호
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• pp.1-17
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• 1996

To demonstrate the clinical usefulness of electroencephalography (EEG) and factors increasing the usefulness of EEG, the authors evaluated each relationship between EEG related factors and clinical variables, and neuroimaging studies (CT and MRI)-related factors, and factors which are related with routine neurological examination for 207 patients who had been evaluated with both of EEG and neuroimaging study(CT or/and MRI). The results were as follows: 1) Abnormality of EEG findings had significant relationships with chief complaints, diagnosis, medication use, seizure attack, pathological reflex, and level of consciousness. However there were no significant correlations between abnormality of EEG findings and neuroimaging studies (CT and MRI)- related factors. 2) Laterality of EEG findings had significant relationships with abnormality, laterality, and focality of CT findings, and also with abnormality of MRI findings. But there were no significant correlations between laterality of EEG findings and clinical variables, and neurological examination-related factors. 3) Anterior-posterior distribution of EEG findings was significantly related with medication use. 4) Focality of EEG findings had significant relationships with sex, sensory dysfunction sign, and cerebellar dysfunction sign. But there were no significant correlations between focality of EEG findings and neuroimaging studies(CT and MRI) related factors. 5) Abnormal EEG pattern had significant correlations with various factors, such as age, chief complaints, duration from onset of symptom to taking MRI, seizure attack, abnormality and nature of lesion in CT findings, cortical atrophy in MRI findings, motor dysfunction sign, sensory dysfunction sign, and pathological reflex. 6) With abnormality on sleep activation, age, age of onset, seizure attack, ventricular enlargement in CT findings, and abnormality of MRI findings were significantly correlated. 7) With abnormality on hyperventilation activation, duration of illness and laterality of MRI findings were significantly correlated. Above results may suggest that abnormality of EEG findings is more closely related with functional change of the brain than structural changes of the brain and laterality of EEG findings is vice versa. And also that medication use has an influence on anterior versus posterior distribution of EEG findings and focality of EEG findings is not related with structural changes of the brain. Activation with sleep may be effective to show age differences and provocation of seizure activity and hyperventilation may be effective to detect the abnormal EEG findings by cerebrovascular insufficiency.

• Biomolecules & Therapeutics
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• 제28권3호
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• pp.230-239
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• 2020

Previous studies have shown disrupted synaptic plasticity and neural activity in depression. Such alteration is strongly associated with disrupted synaptic structures. Chronic stress has been known to induce changes in dendritic structure in the basolateral amygdala (BLA) and medial prefrontal cortex (mPFC), but antidepressant effect on structure of these brain areas has been unclear. Here, the effects of imipramine on dendritic spine density and morphology in BLA and mPFC subregions of stressed mice were examined. Chronic restraint stress caused depressive-like behaviors such as enhanced social avoidance and despair level coincident with differential changes in dendritic spine structure. Chronic stress enhanced dendritic spine density in the lateral nucleus of BLA with no significant change in the basal nucleus of BLA, and altered the proportion of stubby or mushroom spines in both subregions. Conversely, in the apical and basal mPFC, chronic stress caused a significant reduction in spine density. The proportion of stubby or mushroom spines in these subregions overall reduced while the proportion of thin spines increased after repeated stress. Interestingly, most of these structural alterations by chronic stress were reversed by imipramine. In addition, structural changes caused by stress and blocking the changes by imipramine were corelated well with altered activation and expression of synaptic plasticity-promoting molecules such as phospho-CREB, phospho-CAMKII, and PSD-95. Collectively, our data suggest that imipramine modulates stress-induced changes in synaptic structure and synaptic plasticity-promoting molecules in a coordinated manner although structural and molecular alterations induced by stress are distinct in the BLA and mPFC.

• 암석학회지
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• 제10권3호
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• pp.233-245
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• 2001

NMR분광법은 현재 화학에서 빼 놓을 수 없는 아주 중요한 연구방법의 하나지만 또한 지질학의 연구에 있어서도 초전도 자석의 발달과 함께 그 중요성이 부각되고 있다. 지질학에 있어서 NMR의 연구 대상 원소로는 광물의 주 구성 성분이며 여러 가지 구조적 정보를 갖고 있는 $^{29}Si$, $^{27}Al$ 등이 유용하게 사용되며 이들은 각각 다른 여러 정보들을 제공한다. 이 밖에도 $^{23}Na$와 같은 알칼리금속과 더불어 다양한 핵종들이 지질학에서 NMR로 연구되고 있다. NMR을 이용하여 다양한 방면의 연구들이 가능한데 NMR은 XRD, TEM보다도 더욱 작은 미시적인 (분자적 관점에서의) 구조 연구에 사용될 수 있다. 이러한 연구를 통해 Al, Si 질서-무질서, 산소원자와의 배위수, 인근의 다른 양이온의 분포 등을 포함한 구조적 정보를 알 수 있다. 또한 NMR의 또 다른 장점은 정적인 미시 구조뿐만 아니라 분자들의 움직임(dynamics)에 대한 정보도 알 수 있다는 것이다. 이러한 동적인 정보는 기존의 어느 방법으로도 알기 어려웠던 부분이고 NMR을 통하여 분자들의 상호 교환 속도와 활성화 에너지 등에 대한 폭 넓은 이해가 가능할 수 있다. 이 밖에 NMR을 이용하여 비정질 물질에 대한 구조와 더불어 지표면에서 산출되는 유기물에 대한 성분 및 구조도 아주 중요하게 연구될 수 있는 분야이다.

• 한국지능시스템학회논문지
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• 제24권3호
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• pp.337-342
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• 2014

국제해사기구(IMO)는 해상에서의 안전과 보안, 환경의 보호를 위해 선박의 출항에서 입항에 이르기까지 항해와 관련된 정보를 전자 적인 방법으로 조화롭게 공유 통합 표현 분석하기 위해 e-Navigation 이라는 전략적 추진체계를 수립, 채택, 실행을 진행하고 있다. 본 논문에서는 e-Navigation의 실효적 시행에 대비하여 국내에서 운영 중인 GICOMS에 요구되는 개선방안 및 추가 시스템을 식별하기 위한 구조모델을 수립하는데 목적이 있다. 이를 위해서 GICOMS의 문제점을 조사하고, 전문가그룹의 브레인스토밍(brainstorming) 과정을 통해 GICOMS 개선을 위한 9개의 추진과제를 도출하였다. 이들 과제에 대하여 퍼지구조모델(FSM, Fuzzy Structural Modeling)을 이용하여 의식구조를 분석하고 요소 간 상호관계를 파악할 수 있는 구조모델을 제시하였다. 그 결과 GICOMS 개선방안 으로 "GICOMS 고도화"가 최상위층레벨 요소로 파악되었고, 최하층레벨은 "정보생산체제 개선", "정보제공방안 개선", "GICOMS와 VTS 상호연동"과 "글로벌 안전협력 네트워크 구축"으로 나타났다. 중간층레벨은 "e-Navigation 대응체계 구축", "해양사고예방체계 강화", "VMS 기능 고도화"와 "이용 활성화"로 파악되었다. 특히 최종목표인 "GICOMS 고도화"는 "VMS 기능 고도화"와 "이용 활성 화" 항목으로부터 많은 영향을 받고 있음을 알 수 있었다. 본 연구에서 구축한 GICOMS 고도화 구조모델을 기반으로 최첨단 IT를 활용한 시설 장비 전문인력의 개선 및 보강과 해양종사자 중심의 이용자 전환 등의 고도화 방안을 제시하였다.

• Advances in concrete construction
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• 제9권2호
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• pp.207-215
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• 2020

This paper describes the experimental studies carried out to determine the properties of fresh and hardened concrete with Recycled Plastic Waste (RPW) as a partial replacement material for fine aggregates. In the experimental study, RPW was used for replacing river sand and manufactured sand (M sand) aggregates in concrete. The replacement level of fine aggregates was ranging from 5% to 20% by volume with an increment of 5%. M40 grade of concrete with water cement ratio of 0.40 was used in this study. Two different types of RPW were used, and they are (i) un-activated RPW and (ii) activated RPW. The activated RPW was obtained by alkali activation of un-activated RPW using NaOH solution. The hardened properties of the concrete determined were dry density, compressive strength, split tensile strength, flexural strength and ultrasonic pulse velocity (UPV). The properties of the concrete with river sand, M sand, activated RPW and un-activated RPW were compared and inferences were drawn. The effect of activation using NaOH solution was investigated using FT-IR study. The micro structural examination of hardened concrete was carried out using Scanning Electron Microscopy (SEM). The test results show that the strength of concrete with activated RPW was more than that of un-activated RPW. From the results, it is evident that it is feasible to use 5% un-activated RPW and 15% activated RPW as fine aggregates for making concrete without affecting the strength properties.

• 한국건축시공학회지
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• 제20권5호
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• pp.409-416
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• 2020

본 연구는 W/C 50%의 일반강도 조건에서 OPC, FA 및 BS 시멘트의 종류를 변화시켜 콘크리트의 강도 증진 성상을 한랭기 온도의 4~17℃의 평균 양생온도에서 검토하고, 등가재령에 의한 강도 해석모델을 이용하여 강도 증진 해석을 수행하고, 기온저하에 따른 기온보정강도를 제안하고자 하였다. 본 실험의 결과 등가재령을 이용하여 Plowman 모델식으로 강도증진을 해석하였고, 대체로 양생온도가 낮을수록 강도증진이 지연되는 경향을 나타내었다. 이에 양생온도 저하에 따른 강도보정을 3MPa 단위로 실시하였고, 이를 토대로 배합강도 결정시 결합재 종류 및 관리재령별 기온보정강도(T_n)을 제안하였다.

• 한국수정란이식학회지
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• 제33권2호
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• pp.61-68
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• 2018

The major focus of this study is to analyze the expression of bovine MMPs and to monitor their activity during the estrus cycle and pregnancy. During pregnancy, MMP-2 expression was detectable around 30 days but became insignificant by 60 days, then started to increase again around 90 days and reached the maximum at 250 days. The activity of MMP-2 protein changed in accordance with its expression level. As expected, the level of TIMP-2 exhibited a reverse pattern. About MMP-9, high level expression was observed as early as 30 days and gradually increase until 90 days. Then started to decrease after 250 days. Again, the sites of MMP-9 expression were similar to those of MMP-2. On the other hand, expression of TIMP-3 remained low until 90 days but showed a small and temporal increase around 250 days. In summary, expression of different MMPs were differentially regulated during estrus cycle and pregnancy. While the expression of MMP-2 was high in estrus cycle, MMP-9 slowly takes over with the progression of pregnancy. These results indicated that the luteal tissue perform distinct functions during pregnancy and estrus. Perhaps the activity of MMP-2 is required for the structural remodeling of luteum, resulting the suppression of P4 inflow from blood. On the other hand, steady maintenance of MMP-9 throughout luteal development is important for the activation of cell proliferation, maturation and angiogenesis.

• Nuclear Engineering and Technology
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• 제43권2호
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• pp.149-158
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• 2011

Metal waste generated from the pyroprocessing of 10 MtU of spent fuel was classified by comparing the specific activity of a relevant radionuclide with the limit value of the specific activity specified in the Korean acceptance criteria for a lowand intermediate-level waste repository. A Korean Optimized Fuel Assembly design with a 17${\times}$17 array, an initial enrichment of 4.5 weight-percent, discharge burn-up of 55 GWD/MtU, and a 10-year cooling time was considered. Initially, the mass and volume of each structural component of the assembly were calculated in detail, and a source term analysis was subsequently performed using ORIGEN-S for these components. An activation cross-section library generated by the KENO-VI/ORIGEN-S module was utilized for top-end and bottom-end pieces. As a result, an Inconel grid plate, a SUS plenum spring, a SUS guide tube subpart, SUS top-end and bottom-end pieces, and an Inconel top-end leaf spring were determined to be unacceptable for the Gyeongju low- and intermediate-level waste repository, as these waste products exceeded the acceptance criteria. In contrast, a Zircaloy grid plate and guide tube can be placed in the Gyeongju repository. Non-contaminated Zircaloy cladding occupying 76% of the metal waste was found to have a lower level of specific activity than the limit value. However, Zircaloy cladding contaminated by fission products and actinides during the decladding process of pyroprocessing was revealed to have 52 and 2 times higher specific activity levels than the limit values for alpha and $^{90}Sr$, respectively. Finally, it was found that 88.7% of the metal waste from the 17${\times}$17 Korean Optimized Fuel Assembly design should be disposed of in a deep geological repository. Therefore, it can be summarized that separation technology with a higher decontamination factor for transuranics and strontium should be developed for the efficient management of metal waste resulting from pyroprocessing.