• 자원리싸이클링
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• 제25권3호
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• pp.82-87
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• 2016

차세대 이차전지로서 주목받고 있는 리튬-공기 전지와 소듐-공기 전지를 에테류계 전해질을 이용하였을 시 방전 후 생성물을 분석 하였다. FESEM을 통하여 확인한 결과 리튬-공기 전지와 소듐-전지의 방전 후 생성된 입자의 형태는 좁쌀 모양을 보였으며, 두 전지 시스템에서 큰 차이를 보이지 않았다. 하지만 XRD를 통하여 확인 하였을 시 리튬-공기 전지는 비정질 형태의 $Li_2O_2$ 그리고 소듐-공기에서는 결정질의 $NaO_2$가 생성되는 것을 확인 할 수 있었다. 본 연구를 통하여 차세대 전지 시스템으로 주목받고 있는 리튬-공기 전지와 소듐-공기 전지의 기본적인 구동 원리를 이해할 수 있었다.

• Journal of Power Electronics
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• 제14권3호
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• pp.531-540
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• 2014

A novel carrier-based PWM (CBPWM) strategy of a three-level NPC converter is proposed in this paper. The novel strategy can eliminate the low-frequency neutral point (NP) voltage oscillation under the entire modulation index and full power factor. The basic principle of the novel strategy is introduced. The internal modulation wave relationship between the novel CBPWM strategy and traditional SPWM strategy is also studied. All 64 modulation wave solutions of the CBPWM strategy are derived. Furthermore, the proposed CBPWM strategy is compared with traditional SPWM strategy regarding the output phase voltage THD characteristics, DC voltage utilization ratio, and device switching losses. Comparison results show that the proposed strategy does not cause NP voltage oscillation. As a result, no low-frequency harmonics occur on output line-to-line voltage and phase current. The novel strategy also has higher DC voltage utilization ratio (15.47% higher than that of SPWM strategy), whereas it causes larger device switching losses (4/3 times of SPWM strategy). The effectiveness of the proposed modulation strategy is verified by simulation and experiment results.

• 한국실내디자인학회논문집
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• 제18권1호
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• pp.19-26
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• 2009

Aalto designed his own modern architecture in comparison with other modern architects of his days. It is because Aalto went beyond the principle of dogmatic functionalism based on his attitude not to copy images of functionalism but to fulfill function of the building. He decided architectural form and space according to logical basis including the effective use of light and sound. Vuoksenniska church, as is called the most exceptional and notable church in his works, was designed based on the fulfillment of program. As he knew that the program needed the extension of the main church space into social areas, he put emphasis on individuality of space rather than the wholeness of space. Sound and light analysis of Vuoksenniska church shows that Aalto tried to have adequate environment of each space at the start and Integrate them later. The spatial configuration of Vuoksenniska church shows that the individuality of space has priority over the wholeness of spaces. Discordance between roof form and ceiling is the best example for this matter. Aalto designed various windows that have different sizes, figure and location to induce desirable light for each space of the church. He also adjusted the shape of the ceiling and the angle of wall for a effective sound transmission. This result indicates that he knew the activity of the church is normally confined to one weekly morning and the whole space Is hardly used as a religious purpose.

• Journal of Power Electronics
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• 제13권6호
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• pp.1058-1069
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• 2013

This paper proposes and designs a new output filter called an LCFL filter for application to three phase three wire shunt active power filters (SAPF). This LCFL filter is derived from a traditional LCL filter by replacing its capacitor with a C-type filter, and then constructing an L-C-type Filter-L (LCFL) topology. The LCFL filter can provide better switching ripple attenuation capability than traditional passive damped LCL filters. The LC branch series resonant frequency of the LCFL filter is set at the switching frequency, which can bypass most of the switching harmonic current generated by a SAPF converter. As a result, the power losses in the damping resistor of the LCFL filter can be reduced when compared to traditional passive damped LCL filters. The principle and parameter design of the LCFL filter are presented in this paper, as well as a comparison to traditional passive damped LCL filters. Simulation and experimental results are presented to validate the theoretical analyses and effectiveness of the LCFL filter.

• 전기학회논문지
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• 제65권8호
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• pp.1369-1375
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• 2016

A rapid progress of the next-generation non-volatile memory device has been made in recent years. Metal/insulator/Metal multi-layer structure resistive RAM(ReRAM) has attracted a great deal of attention because it has advantages of simple fabrication, low cost, low power consumption, and low operating voltage. This paper describes the working principle of the ReRAM device, a review of fabrication techniques, and characteristics of flexible ReRAM devices using graphene oxide as an insulating layer and ReRAM devices using multi-layered insulator. The switching characteristics of the above ReRAM devices have been compared. The oxidized graphene could be employed as an insulator of next generation ReRAM devices.

• Nuclear Engineering and Technology
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• 제21권1호
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• pp.56-61
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• 1989

Borresen의 1.5군 소격 확산이론에 의거하여 2군 중성자 속에 대한 adjoint 함수를 근사적으로 계산할 수 있는 한가지 간단한 방법을 제안하였다. 이 방법에서는 열 중성자 속에 대한adjoint 함수의 누설항을 1.5군 이론의 원리에 입각하여 기하학적 buckling에 의해 근사적으로 기술하게 되는데 이때 그 기하학적 buckling은 속중성자속의 adjoint 함수로부터 구하게 된다. 한편 제안된 계산 방법의 정확도를 알기 위해 adjoint함수 계산에 대한 KIDD 전산코드의 계산결과와 제안된 방법의 계산결과를 비교하였으며 이로부터 제안된 방법이 정확도면에서 만족스런 adjoint함수를 예측 할 수 있다는 것을 보였다. 뿐만 아니라 이 방법은 섭동 이론과 관련하여 반응도 평가에 유용하게 이용될 수 있다는 것도 보였다.

• 한국정밀공학회지
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• 제20권3호
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• pp.149-156
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• 2003

The estimation of fatigue limit for the component with complicated shape is difficult than of standard fatigue specimen, due to complex test equipment. So, we substitute maximum principle stress from FEM results for fatigue limit diagram made by standard fatigue specimen. Then we can estimate endurance safety of component with high trust. The static stress analysis, the nonlinear contact stress analysis and the model analysis for turbine blade is performed by ANSYS ver. 5.6. the comparison of maximum static stress around hole with maximum contact stress between pun and hole can make the cause of fracture for turbine blade clear. The difference of fatigue limit between fatigue test by standard specimen and in-service mechanical components is due to surface roughness and machining condition etc. In in-service mechanical components, Goodman diagram has to consider surface roughness for failure analysis. To find fracture mechanism of torison-mounted blade in nuclear plant. This study performs the static stress, the nonlinear contact stress and the modal analysis on torison-mounted blade with finite element method and makes the estimation for safety of turbine blade.

• 대한한의학원전학회지
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• 제20권1호
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• pp.39-48
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• 2007

The first chapter of the Oh Sib Young(五十營) explains that the length of the measurement of channels(脈度) is sixteen zahngs two cheocks(16丈2尺). The second chapter says that nourishing gi(營氣) circles around(周行) the whole body 50 times during 13,500 times of breathing in twenty-four hours. The third chapter explains that the total length reaches 810 zhangs(810丈) if it circles around 50 times. Through construction of word, comparison of annotation, investigation, literal translation, free translation, conclusion analysis of these ancient writings, the following results were obtained. In the second chapter, "twenty five bun(二十五分)" should be modified into "twenty bun one Ii six ho(二十分一釐六毫) " or "twenty bun and the rest(二十分有奇)", "forty bun(四十分)" should be changed into "forty bun sam Ii two ho(四十分三釐二毫)" or "forty bun and the rest", and "five su twenty bun(五宿二十分)" should be modified into "five su twenty one bun six li(五宿二十分六釐)" or "two hundred ten bun and the rest(二百十分有奇)" in order to clarify their meanings.

• The Journal of Asian Finance, Economics and Business
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• 제6권1호
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• pp.261-271
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• 2019

The study aims to investigate corporate social responsibility (CSR) best practices of the world automotive industry - Peugeot, BMW, Ford, Hyundai and Toyota among others - and recommend that they plan their business strategies and managerial responses accordingly. Based on the comparative research and case studies, this research finds that all five automobile manufacturers have taken very similar measures and actions in order to establish and maintain a high level of CSR practices. Sustainability was a core value in all five companies and served as a guiding principle in every aspect and approach of their business. This study finds that all five companies have CSR strategies in place to increase energy efficiency as well as reduce the usage and wastage of water in their production and plants. This research also finds that all companies monitor their suppliers and their own production process to ensure that they maintain their CSR standards. More impressively, this sustainable management practice is transferred along the companies' supply chain through education and training. Their suppliers and business partners are closely monitored to make sure that their high CSR standards are respected and followed. However, we find that there also are some differences in terms of their CSR deliveries and activities.

• Structural Engineering and Mechanics
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• 제67권2호
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• pp.125-130
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• 2018

This study deals with buckling analysis with stretching effect of functionally graded carbon nanotube-reinforced composite beams resting on an elastic foundation. The single-walled carbon nanotubes (SWCNTs) are aligned and distributed in polymeric matrix with different patterns of reinforcement. The material properties of the CNTRC beams are estimated by using the rule of mixture. The significant feature of this model is that, in addition to including the shear deformation effect and stretching effect it deals with only 4 unknowns without including a shear correction factor. The equilibrium equations have been obtained using the principle of virtual displacements. The mathematical models provided in this paper are numerically validated by comparison with some available results. New results of buckling analyses of CNTRC beams based on the present theory with stretching effect is presented and discussed in details. the effects of different parameters of the beam on the buckling responses of CNTRC beam are discussed.