• 한국지구물리탐사학회:학술대회논문집
• /
• 한국지구물리탐사학회 2006년도 공동학술대회 논문집
• /
• pp.17-22
• /
• 2006

Shear modulus is directly linked to material's stiffness and is one of the most critical engineering parameters. Seismically, shear-wave velocity (Vs) is its best indicator. Although methods like refraction, down-hole, and cross-hole shear-wave surveys can be used, they are generally known to be tougher than any other seismic methods in field operation, data analysis, and overall cost. On the other hand, surface waves, commonly known as ground roll, are always generated in all seismic surveys with the strongest energy, and their propagation velocities are mainly determined by Vs of the medium. Furthermore, sampling depth of a particular frequency component of surface waves is in direct proportion to its wavelength and this property makes the surface wave velocity frequency dependent, i.e., dispersive. The multichannel analysis of surface waves (MASW) method tries to utilize this dispersion property of surface waves for the purpose of Vs profiling in 1-D (depth) or 2-D (depth and surface location) format. The active MASW method generates surface waves actively by using an impact source like sledgehammer, whereas the passive method utilizes those generated passively by cultural (e.g., traffic) or natural (e.g., thunder and tidal motion) activities. Investigation depth is usually shallower than 30 m with the active method, whereas it can reach a few hundred meters with the passive method. Overall procedures with both methods are briefly described.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 초전도 자성체
• /
• pp.17-20
• /
• 2002

The effects of relatively low lead content (0.2~0.3) on the 2223 phase formation and transport property of Bi-2223/Ag tapes have been investigated. The results show that lead contents have great impact on the phase assemblage of precursors, subsequently, on the phase formation and transport property of silver sheathed BSCCO-2223 tapes. Powders containing Pb=0.25 and Pb=0.3 resulted in the nearly identical $J_c$ values in fully processed tapes, but leaded to significant difference on the phase formation process. For the case of Pb=0.2, both low conversion fraction of 2212 to 2223 and low $J_c$ value were obtained in final reacted tape, which was probably due to lack of enough liquid phase to facilitate the phase transformation.

• 폴리머
• /
• 제37권5호
• /
• pp.613-617
• /
• 2013

나노입자크기의 케냐프섬유를 폴리프로필렌에 첨가하였을 시, 복합소재의 물성변화를 관찰하였다. 천연크기의 케냐프섬유를 나노입자크기의 케냐프섬유로 대체하였을 시, 그 복합소재의 인장강도, 휨강도, 충격강도, 열변형온도가 증가한 반면에, 용융지수, 연신율(%), 충격강도 등이 감소하였다. 이는 나노입자크기의 케냐프섬유가 폴리프로필렌과 접촉하는 표면적의 증가와 섬유표면에 존재하는 휘발성 추출물질 등의 불순물의 감소에 따른 것으로 판단된다.

• 한국재료학회지
• /
• 제4권7호
• /
• pp.823-827
• /
• 1994

Diglycidy1 ether of bisphenol A(DGEBA)/4, 4'-methylene dianiline(MDA) 계에 malononitrile(MN)과 hydroquinone(HQ)을 도입한 계의 기계적 특성을 연구하였다. $80^{\circ}C$에서 1.5hr경화시킨후, $150^{\circ}C$에서 1hr 더 경화시킨 시편을 제조하여 시험하였으며, 사슬확장제로 작용하는 MN과 반응 가속제로 작용하는 HQ가 기계적 물성에 미치는 영향을 연구하였다. MN과 HQ의 첨가량이 증가함에 따라 충격특성은 크게 개선된 반면, 딘장특성은 감소하였다.

• 산업식품공학
• /
• 제15권2호
• /
• pp.169-174
• /
• 2011

This study was performed to analyze the effects of ultra fine pulverization (UFP) on the physicochemical properties of sweet potato starch (SPS). The average diameter and specific surface area of the SPS was decreased from 22.94 to 10.25 $\mu$m and from 0.879 to 1.909 $m^2$ /g throughout UFP, respectively, and the damaged starch content was increased from 13.7 to 99.2%. The pulverized sweet potato starch (PSPS) had higher swelling power, solubility, and transmittance values than the SPS. X-ray diffractograms revealed that the SPS had a C-type pattern, which disappeared in PSPS. The rapid visco analysis (RVA) characteristics, peak viscosity, break down, and set back of SPS ceased to exist in PSPS. According to differential scanning calorimetry (DSC) curves, the peak temperature ($T_p$) and gelatinization enthalpy ($\Delta$E) of SPS were $71.95^{\circ}C$ and 10.40 J/g, respectively, while these remained undetected in PSPS. The enzymatic digestibilities of SPS and PSPS were 61.7 and 84.7%, respectively.

• 한국콘텐츠학회논문지
• /
• 제18권1호
• /
• pp.132-142
• /
• 2018

본 연구는 기업 외부와 내부 환경요소들이 외부주체와의 협력 추진에 미치는 영향을 기업의 해외직접투자로서의 해외생산법인의 유무에 따른 차이와 함께 규명하고자 한다. 본 연구는 지금까지 협력(제휴)과 관련하여 그 결정요인에 대한 연구는 다양하게 분석이 이루어 졌으나, 해외직접투자의 유무에 따라 외부와 내부환경요소로 나뉘어 복합적 분석을 한 연구는 거의 찾아보기 어렵기 때문에 이를 규명하고자 하였다. 분석 결과로는 해외직접투자를 한 기업은 내부요인 중 설비투자의 효율, 가격경쟁력, 3년간 투자실적이 각각 유효한 제휴의 동기로 나타났고, 해외직접투자를 하지 않은 기업은 외부요인인 비용구조의 불확실성, 내부요인인 가격경쟁력, 투자실적이 유효한 결과로 나타났다. 결국, 본 연구에서는 해외직접투자를 한 기업과 해외직접투자를 하지 않는 기업은 모두 내부역량인 가격경쟁력과 3년간의 투자실적이 중요한 협력의 동기가 된다는 것과, 해외투자를 한 기업과 해외투자를 하지 않는 기업의 차이는 해외직접투자를 한 기업은 내부요인에서 설비투자의 효율이, 해외직접투자를 하지 않는 기업은 외부요인 중 비용구조의 불확실성이 각각 주요한 환경요인이 된다는 것을 규명하였다. 종합하여 보면, 본 연구의 시사점은 기업의 내부역량은 협력의 중요한 동기가 된다는 동시에 내부역량 강화는 또한 기업이 다른 기업과의 협력의 기회를 넓혀준다는 것이다.

• Membrane and Water Treatment
• /
• 제9권5호
• /
• pp.317-325
• /
• 2018

Polyvinyl chloride (PVC) ultrafiltration (UF) membrane was modified by silica sol in the coagulation bath during non-solvent induced phase separation (NIPS) process. The effects of silica sol concentrations on the morphology, surface property, mechanical strength and separation property of PVC UF membranes were systematically investigated. PVC membranes were characterized by Fourier transform infrared spectroscopy (FTIR), energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), contact angle goniometry and tensile strength measurement. The results showed that silica had been successfully assembled on the surface of PVC UF membrane. With the increase of silica sol concentration in the coagulation bath, the morphologies of PVC UF membranes changed from cavity structure to finger-like pore structure and asymmetric cross-section structure. The hydrophilicity and permeability of PVC UF membranes were further evaluated. When silica sol concentration was 20 wt.%, the modified PVC membrane exhibited the highest hydrophilicity with a static contact angle of $36.5^{\circ}$ and permeability of $91.8(L{\cdot}m^{-2}{\cdot}h^{-1})$. The structure of self-assemble silica had significant impact on the surface property, morphology, mechanical strength and resultant separation performance of the PVC membranes.

• 지식경영연구
• /
• 제14권1호
• /
• pp.39-55
• /
• 2013

As the importance of intellectual property rights for the 21st century challenge became prominent, many companies have been trying to secure many rights competitively. In particular, application numbers of patent that represents technology has been increased continuously. Korean companies were not exception; mainly in large companies, there have been continued the efforts to grow the number of patent applications in quantitative volume. But the issues that how viable patents the companies have, how effectively the companies manage, and how economically usable the patents are, are totally different from quantitative management level. As such, the issue is connected to how to assess the patent management level of companies. On the other side of quantitative growth of patent that companies hold, there are some problems such as the difficulties to determine if the patents hold substantial values, and the difficulties to determine whether the patent are managed effectively. In addition, as the numbers of patent application and registration of companies are increased, the cost for patent holding and managing increase. It is required to pay continuous attention to the cost of patent management because patent registration fee has a property that increases rapidly with time and burden for patentee become heavier. As a result of analysis and interpretation, we confirmed that quantitative management, particularly the number of patent applicant does not make positive impact on how to use patent after application. Rather, it is observed that the economical usage is influenced positively by the efforts of patent applicants such as considering for the time of patent examination, paying attention to receive patent registration decision. Therefore, this study shows that efforts patent applicants provide in management level after application time are important to maintain the value of patents.

• 대한안전경영과학회지
• /
• 제13권3호
• /
• pp.133-143
• /
• 2011

It seems required to determine what might affect the technological innovation activities of manufacturing companies and what kind of role they could play for them to carry out technological innovation activities in an effective way. The objective of the present study is thus to conduct a depth empirical analysis of the structural relations among business environment, technological innovation activities and performance of manufacturing companies. From the analysis, following outcomes could be drawn: First, with regard to the relationship between business environment and technological innovation activities of manufacturing companies, it has become clear that the external environment is a factor that can influence technological innovation activities such as management of technical property, technological innovation system as well as technical network, while it exercises no impact upon adaptation of manufacturers to new technologies. The internal environment, on the other hand, turns out to have influence on such overall factors of technological innovation activities as management of technical property, technological innovation system, adaptation to new technologies and technical network; and Second, as for the relationship between technological innovation activities and their performance, it has been obvious that management of technical property and technological innovation system, both factors of technological innovation activities, affect the performance of product development and financial achievements of manufacturing companies. Their adaptation to new technologies will also affect their performance of product development as well as financial achievements. These findings suggest that it is important for manufacturing companies to set up an operating system that may be able to upgrade the practical applicability of their technological development activities in an attempt to promote performance of their technological innovation activities.

• 한국산학기술학회논문지
• /
• 제14권2호
• /
• pp.542-547
• /
• 2013

본 연구에서는 알루미늄 폼 코어 복합재료의 기계적 성질을 시뮬레이션 해석을 통하여 고찰하였다. 시험편 모델에는 50J, 70J, 100J의 충격에너지를 가하였다. 50J, 70J 및 100J의 충격에너지에 대해서는 각각 3.4 ms, 3.2 ms 및 3.2 ms의 시점에서 최대하중이 발생하였다. 50J의 충격에너지를 가한 경우는 스트라이커가 복합재료의 상부 면재를 뚫고, 심재까지 손상을 입혔다. 그러나 하부 면재까지는 손상이 없이 그대로이었고 52 J의 에너지가 발생하였다. 70J의 충격에너지를 가한 경우는 스트라이커가 상부 면재를 관통한 후 하부 면재까지 손상을 주었고 65 J의 에너지가 발생하였다. 100J의 충격에너지를 가한 경우는 스트라이커가 면재와 심재를 완전히 관통하여 손상을 주었다. 스트라이커가 상부 면재를 관통하는 시점에서는 최대하중이 되고 그 후로는 하중이 급격히 감소하다가 하부 면재에 도달할 때에 다시 급격히 증가하고 있다가 감소하였고 95 J의 에너지가 발생하였다.