• Journal of the KSME
• /
• v.30 no.4
• /
• pp.367-373
• /
• 1990

초정밀 절삭용 다이아몬드 공구의 날끝 형상에 관해서는 여러 가지 설계안이 개발되어 제각기 성공적으로 사용되고 있지만 제품 품질의 균일성, 즉 성능과 수명의 차이는 아직까지 미해결이다. 또한, 초정밀공구의 날끝 능선에 관해서 최근 측정 데이터가 발표되고 있으나, 양호한 날끝능선, 불량한 능선 및 소정의 다듬질이 이루어지지 못하고 수명에 달해버린 능선 등에 대한 제각기의 형상, 구조 등이 밝혀지지 않고 있으며, 공구의 제작법을 개발하는 것은 금후의 연구과제로 남 아있다. 그리고, 단결정 바이트의 연마에 대해서는 많은 기술적인 진전이 이루어져 왔으나, 수 명의 차이는 해결하지 못하고 있다. 이는 날끝능선의 연마방향과 더불어 다이아몬드의 이방성, 원석의 품질 등과 관련이 있다고 볼 수 있다. 공구의 마멸과정이 결정방위에 의존하는 것은 당연하겠지만, 공구의 연마가공에서는 이방성 그 자체가 공구마멸에 나타나는 문제 및 경사면과 여유면의 마멸과 달리 예리한 인선을 둔화시키는 날끝 능선의 마멸은 어떻게 진행되는가가 문 제이며, 공구의 결정방위와 성능, 수명과의 관련은 실험적으로 해명되어야 할 것이다. 또한 재 료인 다이아몬드 원석에 있어서도, 커다란 결함이 발견된 것은 제외되지만 극히 경미한 결함은 어디까지 허용될 것인지가 문제이다. 내부응력, 착색 등 결함의 인자는 다양하지만 제각기 공구 의 성능 및 수명과의 관련은 명확하게 밝혀져 있지 않다. 이러한 인자 중에서도 어느 것이 가장 크게 영향을 미치는지 확인된다면 커다란 진보가 이루어질 것으로 기대된다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2006.11a
• /
• pp.367-370
• /
• 2006

The ballistic range has long been employed in a variety of engineering fields such as high-velocity impact engineering, projectile aerodynamics, creation of new materials, etc, since it can create an extremely high-pressure state in very short time. Two-stage light gas gun is being employed most extensively. The present experimental study has been conducted to develop a new type of ballistic range which can easily perform a projectile simulation. The ballistic range consists of a high-pressure tube, piston, pump tube, shock tube and launch tube. The experiment is conducted to find out the dependence of various parameters on the projectile velocity. The pressure in high-pressure tube, pressure of diaphragm rupture and projectile mass are varied to obtain various projectile velocities. This study also addresses the effect of the presence of a shock tube located between the pump tube and launch tube on system study. The experimental results are compared with those obtained through an author's theoretical study.

• Journal of the Korea Convergence Society
• /
• v.9 no.7
• /
• pp.33-40
• /
• 2018

The convergence of intelligent information technology and energy technology affects many stakeholders because it involves not only technology itself but also social, institutional and organizational changes. Therefore, it is necessary to develop a back-casting approach to create a new industry that deviates from the path dependence on the traditional energy industry. This study examines the changes in the future energy industry that intelligence information technology will bring, and then we derived the future energy service model that can satisfy the energy policy goals from the national perspective and the interests of each stakeholder at the same time. After that, we analyzed the technical prerequisites for the realization of future energy services and presented the specific configuration technology and the areas that require R&D investment at present.

• Progress in Superconductivity
• /
• v.8 no.2
• /
• pp.127-131
• /
• 2007

We have measured the Hall conductivity (${\sigma}_{xy}$) of c-axis-oriented $MgB_2$ thin films as functions of temperatures and magnetic fields. We found that the Hall conductivity (${\sigma}_{xy}$) is expressed by the sum of two terms, ${\sigma}_{xy}=C_l/H+C_3H$, where the coefficient $C_1\;and\;C_3$ are independent of the magnetic fields and have positive values. The coefficient $C_1$ is strongly dependent on the temperature, while the $C_3$ is weakly dependent on the temperature. We have obtained that the $C_1$ is proportional to $(1- T/T_c)^n$ with n = 4.2, which is consistent with the data observed in $La_{2-x}Sr_xCuO_4$ superconductors with low anisotropy ratio.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2021.06a
• /
• pp.270-270
• /
• 2021

안정적인 취수원의 역할을 할 수 있는 중·대규모의 하천이 없는 연안 및 산간지역의 경우 생활용수 등 각종 용수의 확보를 위하여 지하수자원을 활발히 이용하고 있다. 수문순환의 측면에서 대수층 내 지하수자원은 다양한 경로로 함양되는데, 주변에 물 교환이 활발히 발생하지 않는 연안 및 산간지역의 경우 지하수자원의 주된 함양원은 강수 형태로 내린 물이라고 볼 수 있다. 그러나 최근 전세계적으로 기후변화로 인한 강수패턴의 변화가 발생하고 있고, 특히 국내의 경우 연 총 강수량이 증가하나 무강우일수 및 무강우지속일수의 증가, 강우강도의 증가(기상청, 2018)와 토지이용특성 및 지표면 특성이 변화하면서 지표면 유출량이 증가함에 따라 수문순환의 불균형이 발생하고 있다. 이는 주된 취수원으로 지하수자원에 의존할 수 밖에 없는 연안 및 산간지역의 수자원 확보에 큰 위협이 될 수 있고, 미래 안정적인 수자원 확보가 어려운 상황에 직면할 수 있는 상태이다. 따라서 기존의 하천 위주의 유역 관리계획 수립에서 나아가 가뭄 발생 시 물 부족에 시달리고 있는 연안 및 산간지역의 수자원 관리 및 확보 계획 수립에 대한 요구가 증가하고 있다. 이에 본 연구에서는 안정적인 수자원 확보와 이를 위한 관리 계획의 사각지역에 놓여있는 국내 연안 및 산간지역의 수자원 관리 방안 수립을 위한 초석을 다지기 위하여, 연안 및 산간지역을 대상으로 지하수위 관리 취약성 평가 연구를 수행하였다. 연안 및 산간지역의 주된 취수원인 지하수자원의 주요 평가 인자로 지하수위를 선정하였고, 이에 영향을 미칠 수 있는 수문순환 요소와 인구, 토지이용 특성 등의 평가 인자를 선정하였다. 지표수-지하수 연계와 지역특성을 고려한 수자원 변동 특성을 분석하기 위하여 수문순환 요소간 상관관계를 기반으로 상호 영향성을 규명하였다. 또한 연구 지역의 시간적, 공간적 특성을 평가하기 위하여 공간특성 평가인자와 시간특성 평가 인자를 함께 고려하여 국내 연안 및 산간지역의 지하수위 관리 취약성 평가 연구를 수행하였다. 본 연구의 결과는 지하수자원에 의존할 수 밖에 없는 국내 연안 및 산간지역의 효율적인 수자원 관리 계획을 수립함에 있어 정량적 근거가 될 수 있을 것으로 기대한다.

• Journal of Distribution Research
• /
• v.15 no.2
• /
• pp.35-70
• /
• 2010

In this study, we examined distribution channel relationship by using the idea of Cheong, which is a unique feeling an positive role in Korean society. Companies make great efforts to maintain long-term relationship with buyers. Understanding distinctive relationship system of each culture should precede these efforts to bring effective results. So we considered how Cheong, a meaningful factor in Korean distribution channel, affects relationship quality and performance. As a result of research analysis from 272 survey questionnaires of retailers, engaging in Crops Protected Material industry in Korea, supplier's idiosyncratic investment, retailer's Cheong, and dependence of retailers on suppliers have positive effects on relationship quality. Supplier's idiosyncratic investment and cognitive factors have the highest influence and Cheong, an emotional factor, follows. Dependence, a motivational factor has the least influence. We confirmed that retailer's cooperation and long-term orientation are directly influenced by retailer's commitment. Active cooperation of the retailer, a partner of a distribution channel, is regarded as an essential factor for supplier's effective business. Retailer's commitment increased that cooperation. Retailer's trust and commitment also decreased relationship conflicts. The results of this study imply that companies should increase idiosyncratic investment to improve relationship quality. But increasing idiosyncratic investment is limited because it requires monetary investment. Therefore companies need to recognize the importance of Cheong, revealed as a new factor, improving relationship quality and to make the best use of it. In this study, we contributed theoretically by examining the role of Cheong, and introducing its distribution discipline. We also make practical suggestions about supplier's relationship management.

• Journal of Ginseng Research
• /
• v.10 no.1
• /
• pp.101-107
• /
• 1986

Relationships among ginsenosides, panaxadiol(PD), panaxatriol(PT), and total saponin(TS) in Panax ginseng root (2nd Year) grown with culture solotion different in nitrogen, phosphorus and potassium level were analyzed by simple correlation, multiple regression and standard partial regression coefficient. The closeness between ginsenosides by simple correlation was closely related with the similarity of molecular structure. The content of PT was much attributed to Re and Rg1. The contribution order of ginsenosides for PD was Rb1>Rb2$\geq$Rd>Rc. There was significant positive correlation between PT and PD but PD increased more rapidly than PT. Thus total saponin depended much on PD and PT/PD decreased with the increase of total saponin content. All ginsenosides, especially Re showed decreasing tendency with the increase of root weight.

• Journal of the Korean Institute of Gas
• /
• v.1 no.1
• /
• pp.7-13
• /
• 1997

To investigate the pressure dependence of minimum ignition energy(MIE), thermal ignition theory, concept of heat transfer, ideal gas law, and kinetic theory are discussed. Correlation equations for the MIE and pressure were obtained through a regression analysis of reported data. In the proposed methodology the predicted MIE with pressure variations agree with reported data within a few average absolute deviations(A.A.D.). Therefore the proposed methodology has provided to be the general method for predicting the MIE of hydrocarbons.

• Journal of Distribution Research
• /
• v.3 no.1
• /
• pp.123-143
• /
• 1998

The aim of this paper is to investigate the women's apparel distribution channel in the well-known department stores located in the central Seoul area. Since the department store has its reputation, information and enormous buying power, it is the one of the major leading retails in the women's apparel industry. In doing so, the relationship between the channel members in terms of the level of dependence, power sources and perceived conflict and manifest conflict has been studied. Particularly, based on French and Raven's power sources, position source is added. It refers to a channel member's (Merchandizer in the department store) source over another based on the expection the former (Merchandizer in the department store) will be able to allocate the location and size of the store influencing the latter's sale and profit. The key informants are the merchandizers who work in the apparel companies contracting with major department stores. Finally, of the 284 questionnaires collected, 235 are usable. The hypotheses are tested through LISREL. The results of statistical analysis support that : Dependence has a positive effect on noncoercive bases of power. Coercive bases of power have a positive effect on manifest conflict as well as perceived conflict while noncoercive bases of power have a negative effect mainly on manifest conflict. Thus, the relation between the major department stores and the women's apparel companies in there seems to have bilateral dependence rather than highly unilateral dependence.

• The Journal of Korean Association of Computer Education
• /
• v.9 no.5
• /
• pp.31-39
• /
• 2006

The change into the knowledge based information society requires a transformation of educational paradigm. Accordingly, intelligent learning and distance education are attracting a fair amount of attention. To apply the instructional learning method in this field, we need to consider a individualization of learning, as it were, abstraction of fact and path through learning, which is based on learner's traits, this focus entails a argument for individualized reasoning strategy. Therefore, in this paper, we design a learner's cognitive union, which is based on X-Neuronet(eXtended Neuronet), represent learner's hierarchical knowledge is able to self-learn, and grows adaptive union by proprietor. Additionally, we propose a individualized reasoning strategy, which relies upon learner's cognitive union, and verify the validity.