• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.610-615
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• 2002

This study is to evaluate the risk perception of noise of the ground-crews in the Korean airbases who exposed to noise of jet plane. 1148 ground-crews and 231 pilots of 2 airbases participated in this study. The questionnaires of risk perception with visual analogue scale were completed by the participants. For comparison, the perception of other risks such as beef contaminated with dioxin, AIDS, lung cancer, otitis media, shigellosis, driving, drinking, and smoking were also included in the questionnaire of risk perception. The results of this study suggested the necessity of risk communication about noise and activation of effective hearing conservation program in the Korean air-force.

• Macromolecular Research
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• 제15권2호
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• pp.109-113
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• 2007

The surface molecular motion of monodisperse polystyrene (PS) films was examined using scanning vis-coelasticity microscopy (SVM) in conjunction with lateral force microscopy (LFM). The dynamic storage modulus, E', and loss tangent, $tan\delta$, at a PS film surface with number-average molecular weights, $M_n$, smaller than 30 k were found to be smaller and larger than those for the bulk sample, even at room temperature, meaning that the PS surface is in a glass-rubber transition or fully rubbery sate at this temperature when the $M_n$ is small. In order to quantitatively elucidate the dynamics of the molecular motion at the PS surface, SVM and LFM measurements were performed at various temperatures. The glass transition temperature, $T_g$, at the surface was found to be markedly lower than the bulk $T_g$, and this discrepancy between the surface and bulk became larger with decreasing $M_n$. Such an intensive activation of the thermal molecular motion at the PS surfaces can be explained in terms of an excess free volume in the vicinity of the film surface induced by the preferential segregation of the chain end groups.

• Bulletin of the Korean Chemical Society
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• 제9권3호
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• pp.179-182
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• 1988

A simple correlation between cross interaction constants ${\rho}_{ij}$ and bond lengths in the transition state was obtained ; it has been shown that ${\rho}_{ij}$ corresponds to force constant of activation, which in turn is related to bond length by Badger's rule involving only universal constants. A satisfactory correlation between 4-31G ab initio calculated values of bond length and force constant for C-X streching in the transition state of the methyl transfer reaction, $X^-\;+\;CH_3X\;=\;XCH_3\;+\;X^-$, indicated that Badger's rule can be extended to bonds in the transition state. Independence of ${\rho}_{ij}$ values from the variable charge transmission of reaction centers has been demonstrated with nearly constant, experimentally determined I${\rho}$XYI values, and hence similar degree of bond formation, for various $S_N2$ reactions.

• Transactions on Electrical and Electronic Materials
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• 제5권6호
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• pp.227-232
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• 2004

We investigated a nonvolatile nanomemory element based on boron nitride nanopeapods using molecular dynamics simulations. The studied system was composed of two boron-nitride nanotubes filled Cu electrodes and fully ionized endo-fullerenes. The two boron-nitride nanotubes were placed face to face and the endo-fullerenes came and went between the two boron-nitride nanotubes under alternatively applied force fields. Since the endo-fullerenes encapsulated in the boron-nitride nanotubes hardly escape from the boron-nitride nanotubes, the studied system can be considered to be a nonvolatile memory device. The minimum potential energies of the memory element were found near the fullerenes attached copper electrodes and the activation energy barrier was $3{\cdot}579 eV$. Several switching processes were investigated for external force fields using molecular dynamics simulations. The bit flips were achieved from the external force field of above $3.579 eV/{\AA}$.

• BMB Reports
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• 제43권7호
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• pp.485-490
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• 2010

Neurotrophins regulate many aspects of neuronal function through activation of the high affinity Trk receptors. Shc family proteins are implicated in the coupling of RTK to the Ras/mitogen-activated protein kinase signaling cascade. Here we report that the fourth Shc family member, ShcD, associates with TrkB receptor and regulates BDNF-induced MAPK activation. Yeast two-hybrid assay and Co-IP experiments demonstrate ShcD interacts with TrkB in a kinase-activity-dependent manner. Confocal analysis shows ShcD cololizes well with TrkB in transfected 293T cells. Subsequent mapping experiments and mutational analysis indicate that both PTB and SH2 domains are capable of binding to TrkB and PTB domain binds to TrkB NPQY motif. Furthermore, ShcD is involved in BDNF-induced MAPK activation. In summary, we demonstrate that ShcD is a substrate of TrkB and mediates TrkB downstream signaling pathway.

• 한국표면공학회지
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• 제43권3호
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• pp.132-141
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• 2010

NiTi alloy has been used for orthodontic wire due to good mechanical properties, such as elastic strength and frictional resistance, combined with a high resistance to corrosion. Recently, these wire were coated by polymer and ceramic materials for aesthetics. The purpose of this study was to investigate surface characteristics of polymer coated NiTi alloy wire for orthodontics using various instruments. Wires (round type and rectangular type) were used, respectively, for experiment. Polymer coating was carried out for wire. Specimen was investigated with field emission scanning electron microscopy(FE-SEM), energy dispersive x-ray spectroscopy(EDS) and atomic force microscopy(AFM). The phase transformation of non-coated NiTi wire from martensite to austenite occurred at the range of $14{\sim}15^{\circ}C$, in the case of coated wire, it occurred at the range of $16{\sim}18^{\circ}C$. Polymer coating on NiTi wire surface decreased the surface defects such as scratch which was formed at severe machined surface. From the AFM results, the average surface roughness of non-coated and coated NiTi wire was 13.1 nm, and 224.5 nm, respectively. From convetional surface roughness test, the average surface roughness of non-coated and coated NiTi wire was $0.046{\mu}m$, and $0.718{\mu}m$, respectively.

• 한국운동역학회지
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• 제30권4호
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• pp.285-291
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• 2020

Objective: Shoes midsole are crucial for reducing impact forces on the lower extremity when someone is running. Previous studies report that the cushioning of running shoes make it possible to use less muscular energies. However, the well cushioned shoes result in energy loss as the shoe midsole is compressed. Cushioning reduces the load on the body, it also results in the use of more muscle energy to create propulsion force. The purpose of this study was to investigate the effect of the difference of shoe hardness & resilience on the running. Method: Shoes midsole are crucial for reducing impact forces on the lower extremity when someone is running. Previous studies report that the cushioning of running shoes make it possible to use less muscular energies. However, the well cushioned shoes result in energy loss as the shoe midsole is compressed. Cushioning reduces the load on the body, it also results in the use of more muscle energy to create propulsion force. The purpose of this study was to investigate the effect of the difference of shoe hardness & resilience on the running. Results: In vastus lateralis muscle Activation, Type 55 were significantly higher for Type 50 and X (p=0.019, p=0.045). In Gluteus Maximus muscle activation, Type 55 was significantly lower for type 50 (p=0.005). In loading late, Type 55 and X were significantly higher for type 45 (p=0.008, p=0.006). Conclusion: The components of a shoe are very complex, and there can be many differences in manufacturing as well. Although some differences can be found in the biomechanical variables of the high elastic midsole, it is difficult to interpret the performance enhancement and injury prevention.

• 대한치과교정학회지
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• 제31권6호
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• pp.549-558
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• 2001

본 연구는 협측 이소맹출된 상악 제2대구치의 협측 반대교합을 개선하기 위해 사용되는 maxillary posterior crossbite appliance에 의해 상악 제2대구치의 치근단과 그 주위의 치조골에 발생되는 응력분포를 알아보기 위해 광탄성법을 이용하여 분석하였다. 상악의 치조골을 재현하기 위해 PL-3형의 epoxy resin과 PL-3보다 경질인 레진치아를 사용하여 협측 이소맹출된 상악 제2대구치를 광탄성모형으로 재현하였다. 광탄성 모형상에 maxillary posterior crossbite appliance를 적용하고 힘을 가하기 전과후의 응력분포를 알아보기 위해 원형편광기를 사용하여 모형의 전후방에서 관찰하였다. 이상의 연구를 통해 얻어진 결과는 다음과 같다. 1. 상악 제2대구치의 구개면에 힘을 가한 경우, 협측과 구개측 치근첨에는 무늬차수 0.6차와 치경부에는 무늬차수 0.9차의 응력이 집중이 되어 나타났고 회전중심이 구개측 치근은 치근첨에, 협측 치근은 치근 1/4부위에 발생하였으며 이로 인해 제2대구치에 구개측으로의 비조절성 경사이동 및 회전력이 발생하였다. 2. 상악 제2대구치의 협측면에 힘을 가한 경우에는 구개면에 힘을 가한 경우 보다 협측과 구개측의 치근첨에 더 많은 무늬차수 2.2차의 응력이 발생하였다. 또한 치근하방의 치조골 부위에 응력의 발생과 함께 구개측 치근의 회전중심은 사라지고 협측 치근은 치근첨으로 이동하여 이로 인해 구개측으로의 조절성 경사이동 및 함입력이 발생하였다. 3. 상악 제2대구치의 협측이나 설측에 힘을 가한 경우, 고정원인 제1대구치는 치근첨부위에 소량의 응력이 발생하였고, 편측의 제2대구치에만 힘을 가한 경우보다 양측의 제2대구치에 동시에 힘을 가한 경우에서 더 많은 양의 응력이 제1대구치에 발생하였다. 이상의 결과는 협측 이소맹출된 상악 제2대구치의 구치부 협측 반대교합을 개선하기 위해 사용되는 maxillary posterior crossbite appliance를 적용할 때, 제1대구치의 고정원 상실을 최소화하기 위해서는 편측의 제2대구치를 먼저 개선시키고 그 후 반대측 제2대구치의 개선을 도모하는 것이 바람직하다는 것을 의미한다. 또한 구개측면보다는 협측면에서 견인력을 가하여 제2대구치에 함입력과 구개측으로의 조절성 경사이동을 발생시키는 것이 구치의 정출 및 회전에 의해 야기될 수 있는 교합장애를 방지할 수 있으리라 사료된다.

• 대한약리학회지
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• 제19권2호
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• pp.9-16
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• 1983

현재 사용되고 있는 강심제로는 디지탈리스 배당체가 유일한 약물이지란 그 안전역이 대단히 좁아서 보다 안전한 강심제의 개발이 요구되고 있다. 최근 강심작용이 현저할 뿐 아니라 안전역이 비교적 넓을 것으로 인정되는 higenamine이 개발되어 그 작용기전을 밝히려는 시도가 많이 있었다. 본 연구에서는 higenamine의 강심작용 기전을 규명하기 위한 연구의 일환으로 수축빈도-수축력 상관관계(interval-strength relationship)에 있어서 1) Rested-state수축력 2) Positive inotropic effect of activation(PIEA) 3) Negative inotropic effect of activation(NIEA)에 대한 higenamine의 영향을 $Ca^{++}$및 epinephrine과 비교 분석하였다. 실험결과 칼슘은 PIEA를 증가시키기 보다는 오히려 NIEA의 소멸을 촉진함으로써 강심작용을 나타내며 epinephrine 및 higenamine은 PIEA를 증가시키고 NIEA에는 거의 영향을 미치지 않았다.

• 디지털융복합연구
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• 제12권12호
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• pp.507-512
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• 2014

문화가 공급하는 자와 수요자와의 감정의 공유가 있어야 가능한 것임을 감안해 보더라도 수요자가 그 코드를 제대로 읽어내지 못한다면 문화의 형성은 불가능하기 때문이다. 이에 활발한 도자공예 문화의 보급은 교육의 힘으로 가능하다 할 수 있다. 우리의 도자공예문화 역시 이러한 의미에서 교육의 중요성을 다시금 확인하고 재정비 필요하다. 시대적 지역적인 도자공예가 하나의 문화로 자리매김을 위해서는 무엇보다도 교육 및 활성화 방안이 필요하다. 이에 교육 방법이나 활성화 방안으로 공방 운영에 교육의 중요성을 토대로 도자공방 활성화 방안을 연구 제시하고자 한다.