• The Korean Journal of Malacology
• /
• v.12 no.2
• /
• pp.85-90
• /
• 1996

3종의 복족류(Rapana venosa, Reishia bronni, Anthosiphonaria sirius)와 1종의 다판류, Lepidosona(Lepidosona) coreanica에 대한 18S ribosomal DNA의 염기서열을 밝히고 이들을 이미 보고된 18종의 이매패류, 2종의 복족류 그리고 1종의 다판류의 염기서열과 비교분석하였다. 그 셜과 복족류는 V4 region에서 다른 연체동물과 구별되는 독특한 inseerted sequinces를 가지고 있었으며, V2 region에서 복족류(Prosobranchia와 Pulmonata)와 이매패류(Pteriomorphia 와Heteerodonta) 각각의 두 아강들이 서로 다른 특징적인 insertions 또는 deletions으로 구분되었다.

• Journal of the Korean Home Economics Association
• /
• v.43 no.2
• /
• pp.191-202
• /
• 2005

The purpose of this study was to identify the characteristics of late credit card bill payers. Data were collected through a questionnaire survey of 621 credit card users residing in five metropolitan cities including Seoul and Gyeonggi Province. The results indicated that credit card delinquents showed irrational behavior in managing the use of credit cards. That is, they unnecessarily subscribed for credit cards, used their credit cards without signature, or excessively used the credit cards regardless of their payment capability. From these study results, two recommendations were made : 1) consumer education on credit card use and credit management and 2) law revision on regulating credit card use.

• Polymer Science and Technology
• /
• v.2 no.3
• /
• pp.158-168
• /
• 1991

본고에서는 고분자절연체의 내부전하분포 측정을 위한 측정원리, 측정장치 및 실제측정예 등에 대하여 언급하였다. 이 방법은 고분자내에 존재하는 전하의 종류, 위치 및 전하량에 대한 정보를 얻을 수 있으므로 고분자의 절연성질을 이해하는데 도움을 줄 것으로 생각한다. 특히 폴리에틸렌의 경우 여러 가지 요인, 즉 수지의 종류 또는 첨가제의 유무 등에 의해 각기 다른 내부전하분포를 갖는다는 사실이 밝혀졌다. 이와 같은 사실은 고분자 내부에 존재하는 공간 전하 때문에 외부전압에 의한 전기장이 변형되고 이에 따라 고분자의 절연성질이 변형될 수 있다는 점을 생각할 때 매우 중요한 의미를 갖는다고 할 수 있다. 따라서 고분자의 절연성질에 대한 이해를 높이기 위하여는 절연성질과 내부전하분포와의 관계에 대한 보다 깊은 연구가 이루어져야 할 것으로 생각된다.

• Journal of the Korea Institute of Building Construction
• /
• v.4 no.1
• /
• pp.8-15
• /
• 2004

1997년 11월 IMF 영향에 따른 ○○건설사의 부도로 인해 1년동안 ('97. 11∼'98. 11) 공사가 중단된 채 방치되어 많은 문제점을 안고 공사를 재개하지 못하고 있는 현장이 전국에는 아직도 100여개 정도 산재해 있는 것으로 알고 있다. 이와 같은 현장의 공사재개를 위해서는 다음과 같은 문제점을 검토해야 한다. 첫째 기술적 문제점으로는 기초와 지하주차장 골조공사가 일부 시공중 중단되어 철근이 1년 동안 방치된 채 부식되어 있어 구조물 안전진단은 물론 부도에 따른 기 시공 협력업체들의 채무정리(22개사)에 대한 문제가 해결되지 많아 공사의 재개에 많은 어려움이 있으므로 충분한 사전검토가 필요하다. 둘째 외부적 문제점으로는 그동안 공사중단으로 인한 입주자들에 대한 신뢰확보 즉 조합 및 분양자들이 건설사의 부도로 인한 중도금 납입 거부상태는 물론 선납금, 연체이자 등의 경제적 피해 손실로 발주처에 대한 집단소송 진행 등에 따른 건설사 및 발주처에 대한 불신 해소를 어떻게 하느냐가 공사재개의 중요한 관건이었다.(중략)

• Proceedings of the Korean Society of Soil Zoology Conference
• /
• 2005.09a
• /
• pp.22-22
• /
• 2005

• Proceedings of KHEA Conference
• /
• 2003.04a
• /
• pp.187-187
• /
• 2003

• 전기의세계
• /
• v.44 no.5
• /
• pp.33-38
• /
• 1995

본 내용은 전력케이블의 절연설계의 개념을 소개하고, 최근의 신절연재료이 기술적인 소개와 내수트리절연체의 제특성, 밀착성/박리성 반도전재료의 개선이 어떠한 케이블특성이 향상되어지는가에 대하여 소개한다.

• Polymer(Korea)
• /
• v.35 no.6
• /
• pp.513-519
• /
• 2011

Molecular simulations via the molecular dynamics method have been carried out to investigate the dynamic collision properties of penetrable-sphere model fluids. The collision frequencies, the mean free paths, the angle distributions of the hard-type reflection and the soft-type penetration, and the effective packing fractions are computed over a wide range of the packing fraction ${\phi}$ and the repulsive energy ${\varepsilon}^*$. The soft-type collisions are dominated for lower repulsive energy systems, while the hardtype collisions for higher repulsive energy systems. Very interestingly, the ratio of the soft-type (or, the hard-type) collision frequency to the total collision frequency is directly related with the Boltzmann factor of acceptance (or rejection) probabilities in the canonical ensemble Monte Carlo calculations. Such dynamic collision properties are shown to be restricted for highly repulsive and dense systems of ${\varepsilon}^*{\geqq}3.0 $and ${\phi}{\geqq}0.7$, indicating the cluster forming structures in the penetrable-sphere model.

• Journal of Adhesion and Interface
• /
• v.21 no.4
• /
• pp.129-134
• /
• 2020

Understanding charge trapping at the interface between conjugated semiconductor and polymer dielectric basically gives insight into the development of long-term stable organic field-effect transistors (OFET). Here, the charge transport properties of OFETs using polymer dielectric with various molecular weights (MWs) have been investigated. The conjugated semiconductor, pentacene exhibited morphology and crystallinity, insensitive to MWs of polymethyl methacrylate (PMMA) dielectric. Consequently, transfer curves and field-effect mobilities of as-prepared devices are independent of MWs. Under bias stress in humid environment, however, the drain current decay as well as transfer curve shift are found to increase as the MW of PMMA decreases (MW effect). The charge trapping induced by MW effect is irreversible, that is, the localized charges are difficult to be delocalized. The MW effect is caused by the variation in the density of polymer chain ends in the PMMA: the free volumes at the PMMA chain ends act as charge trap sites, corresponding to drain current decay depending on MWs of PMMA.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.24 no.1
• /
• pp.128-138
• /
• 2019

Effects of feeding type and food resource availability on community structure of mollusks inhabiting hard-bottom subtidal areas were investigated. By following guidance from several references, mollusks observed in this study were divided into 5 groups according to feeding type - 1) grazing, 2) filter feeding, 3) deposit feeding, 4) omnivorous and 5) predation. The results showed that both grazing and filter feeders were the most numerous, explaining grazing type in the East Sea accounting for 47.9%, 32.6% in the South Sea and 29.6% for filter feeding, and filter feeding as a dominant feeding type in Yellow Sea accounting for 42.3%. Results of this study showed distinctive difference in community structure depending on mechanism of feeding type and geographical areas where sampling took place. With the results, attempts were made to understand whether community structure could be affected by feeding type or feeding availability and found out that community structure depended heavily on food resource availability. In the East Sea where marine algal density was high, the algal community in the forms of thick-leathery and sheet often occurred in water column with high transparency which provides proper environment for growth. In the South Sea where grazing and filter feeding types were predominated similarly, the algal density was high, but had the relative highest phytoplankton density. Whereas in the Yellow Sea showing the lowest algal biomass compared to the one in the East and the South Sea, and phytoplankton density was similar to those. It might be a adequate environment for filter feeders than grazers. This study concluded that community structure of mollusks showing high abundance was present where food resource availability with types and quantity was high.