• Polymer(Korea)
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• v.27 no.2
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• pp.98-105
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• 2003

The surface energy and the effect of functional groups on the surface of the ozone-treated low-density polyethylene (LDPE) film were studied. Treatment conditions were treatment time, total amount of transferred ozone, and ozone concentration. The introduction of polar groups on the surface of LDPE film after ozone treatment was confirmed by FTIR-ATR and XPS analyses. Surface fee energy of the LDPE film was examined by a contact angle method. The ozone treated-LDPE film showed a decreased water contact angles about 15$^{\circ}$ mainly due to the increased concentration of oxygen-containing functional groups, which was attributed to the increased surface free energy or $O_{IS}/C_{IS}$Also, the concentrations of the oxygen-containing functional groups on the surface of LDPE film increased with ozone treatment time and concentration, whereas no significant effects were found for the total amount of transferred ozone. From the dyeability test using Kubelka-Munk equation, it was found that the ozone treatment plays an important role in the growth of oxygen-containing functional groups of LDPE film, resulting in the improvement of dyeability for basic dyeing agent.

• Journal of Radiation Protection and Research
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• v.21 no.4
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• pp.285-296
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• 1996

The energy spectra in the air and water of several ${\gamma}-ray$ sources such as Cr-51, Cs-137, Mn-54, Zn-65 have been investigated using the NaI(T1) scintillation detector. General response functions, which can curve fit the measured spectra, have been constructed. We have found that the constructed response functions can successfully represent the measured spectra in the water as well as in the air, It is possible, by comparing the relevant parameters of the response functions, to quantitatively characterize the changing features of the measured spectra as obtained with varying the water depth. Of the response function parameters, those which affect the shape of the full-energy Peak have most notably changed. Besides, those parameters which affect the shapes of the flat continuum, the Compton continuum and edge have also shown slight changes with varying the water depth.

• Journal of Energy Engineering
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• v.24 no.2
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• pp.179-186
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• 2015

This study suggests a few solutions to improve the post-monitoring activities under the Energy Efficiency Labeling Program. First, samples should be selected from each category for the post-monitoring activities, taking account of the consumer's continuous buying behavior, while it is also important to form and operate a deliberation committee. Second, it is necessary to alleviate the checking process of the label content of 9 items which have never been violated the labeling regulation since 2005. This study suggests the detailed checking of label contents and the reinforcement of the measurement of 17 items which have violated labeling more than once over the past few years. Third, this study suggests that the entire post-monitoring process should be disclosed and be posted on the websites of related agencies and on the Internet in general.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.12
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• pp.1669-1674
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• 2012

A commonly analytical estimation of fatigue life on rubber components is using fatigue life equation based on various fatigue test results. However, such method has very restricted applicability in actual designing processes because performing fatigue tests requires a lot of time and money. In addition, non-standard rubber materials and their randomness make it hard to make databases. In this paper, the other fatigue life estimation method using tearing energy was suggested. We performed static and dynamic tearing test about automotive vibration rubber materials and a finite element formulation using a virtual crack to calculate the tearing energy of rubber components with complicated shapes. To using the suggested method, fatigue life of an automotive motor mount has been estimated and verified the reliability of this method by using comparison between the estimated values and the actual fatigue life.

• Korean Journal of Optics and Photonics
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• v.10 no.2
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• pp.162-168
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• 1999

A new design of four-pass dye laser amplifier affording a narrow-bandwidth pulsed output is demonstrated to suppress the amplified spontaneous emission(ASE) carried by the amplifier output and reduce the possibility of parasitic oscillation in the amplifier. By the direct pulsed amplification of a cw 100 mW dye laser under a Q-switched doubled Nd:YAG laser pumping with energy of 5.6 mJ/pulse, high-peak-power pulsed output with 1.5-mJ energy in 130-MHz bandwidth is obtained corresponding to a power gain greater than $2{\times}10^6$ and an energy efficiency of 27%. The ASE ratio in the four-pass amplifier output is dramatically reduced by using a diffraction grating in the amplifier. Compared with the results obtained from the normal operation of the amplifier with no frequency-selective device, the ASE ratio is reduced by a factor in excess of 10 to remain under 1.5% of the amplifier output whereas the total output energy is slightly increased by ~4%.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.1
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• pp.34-39
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• 2017

The recent gradual increase in the energy demand is mostly met by fossil fuel, but the research on and development of new alternative energy sources is drawing much attention due to the limited fossil fuel supply and the greenhouse gas problem. This paper assesses the feasibility of producing fuel energy from a dewatered sewage sludge by microwave-induced pyrolysis with sludge char and graphite receptor. Both receptors produced gas, char, and tar in order from product amount. The gas produced for the sludge char receptor contained mainly hydrogen and methane with a small amount of light hydrocarbons. The graphite receptor generated higher gravimetric tar and generated higher light tar. Through the results, the product gas from the microwave processes of wet sewage sludge might be possible as a fuel energy. But the product gas has to be removed the condensable PAH tars.

• Geophysics and Geophysical Exploration
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• v.5 no.1
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• pp.18-22
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• 2002

As a single arrival traveltime, maximum energy arrival traveltime has been known as the most proper operator for Kirchhoff migration. In case of the model having the simple structure, both the first arrival traveltime and the maximum energy arrival traveltime can be used as the correct operators for Kirchhoff migration. However for some model having the complex and high velocity contrast structure, the migration using the first arrival traveltime can't give the correct depth section. That is, traveltime to be required in Kirchhoff migration is the maximum energy traveltime, but, needs considerably more calculation time than that of first arrival. In this paper, we propose the method for calculating the traveltime approximated to the maximum energy arrival using one-way wave equation. After defining the WAS(Wrap Around Suppression) factor to be used for calculating the first arrival traveltime using one-way wave equation as the function of lateral grid interval and depth and considering the delay time of source wavelet. we calculate the traveltime approximated to the maximum energy arrival. to verify the validity of this traveltime, we applied this to the migraion for simple structure and complex structure and compared the depth section with that obtained by using the first arrival traveltime.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.2
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• pp.1-10
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• 2009

Energy efficient operations are essential to increase the life time of wireless sensor network. A cluster-based protocol is the most common approach to preserve energy during a data aggregation. This paper deals with an energy awareness and autonomous clustering method based on time delay. This method consists of three stages. In the first phase, Candidate Cluster Headers(CCHs) are selected based on a time delay which reflects the remaining energy of a node, with considering coverage efficiency of a cluster. Then, time delay is again applied to declare Cluster Headers(CHs) out of the CCHs. In the last phase, the issue on an orphan node which is not included into a cluster is resolved. The simulation results show that the proposed method increases the life time of the network around triple times longer than LEACH(Low Energy Adaptive Cluster Hierarchy). Moreover, the cluster header frequency is less diverse, and the energy on cluster heads is less spent.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.11
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• pp.2786-2791
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• 2014

This paper describes the smart illuminating system based on the obstacle environmental presetting to improve the user convenience to easy lighting and energy conservation. Obstacle environment has trouble controlling the illuminating equipment using manual buttons in certain circumstances, which requires a smart remote controller. The smart remote controller is operated by the smart phone, motion sensor and timer to turn on and off the lamps. The event sensor module transmits the signals of the event occurrence to equipment on the remote place when smart phone and motion sensor detect an event, and the illuminator received the event turn on or off the lamp. The system results in energy saving by simple on/off control and manipulating the operating time with controlling the illuminating system preset by user's obstacle or preference circumstances. The proposed system implementation is experimented to figure out the energy saving about13.5w/h and the optimized convenience control.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.12
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• pp.1222-1229
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• 2012

For the reduction of electric energy consumption and its efficient use at homes or buildings, a new work item proposal for new architecture and functional requirements of Energy Saving System (ESS) was proposed to IEC TC 100 and accepted as a new project, IEC PT 62654 in 2009. Recently, the final ballot for publication passed without negative votes and IEC TS 62654 was finally published in August 2012. For the verification of this standard, Prototype of ESS system composed of an ESS server, ESS clients, and portable ESS terminal were especially implemented in parallel with the standardization. Electric Power Control and Management (EPCM) protocol for the communication between ESS server and clients was also implemented, which supports self-configuration of ESS network, power consumption monitoring, remote power control, and additional functions for intelligent energy saving services.