• Journal of environmental and Sanitary engineering
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• v.16 no.1
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• pp.108-116
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• 2001

It is difficult to task to achieve high biological nutrient removal from municipal wastewater because of low organic content. Volatile fatty acids(VFAs) produced from acid fermentation of food wastes can be utilized as external carbon sources for the biological nutrient process. Significant reduction and stabilization of the food wastes can also be obtained from the acid fermentation. The objective of this study is to evaluate characteristics of acid fermentation of the food wastes. Results obtained from the batch experiment of various organic wastes showed that the food wastes had high potential to be used as an external carbon source because of the largest production of the VFAs with low nitrogen and phosphorus content. The fish waste was found to be the next possible organic waste, while the others such as radish cabbage and molasses waste showed high VFAs consumption potential as a results of high nitrogen and phosphorus content. alkaline hydrolysis of the food waste was carried out using NaOH prior to the acid fermentation. As the alkali addition increased, solubilization of the organics as well as TSS reduction increased. However, fraction of soluble COD to total COD became stable after a sharp increase. Alkali addition greater than 0.5g NaOH per g TS resulted in significant increase in pH.

• Korea Journal of Hospital Management
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• v.15 no.2
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• pp.1-14
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• 2010

This study tried to analyze about the investment effects on the spent capital and possessed tangible assets of some hospitals during their hospital management. For this analysis purpose, this study used the financial data of 100 hospitals which presented their financial statements to an finance-information company from 2004 to 2006. The analysis was done with PEFR(Percentage of External Funds Required) and Tangible Asset. The FEPR considered the retained interior fund relating to the investment types in the hospital industry. And the Tangible Asset was related to the possession condition of facilities and equipment. The EBIT rate(Earnings before interest and tax to sales) meaning the management performance and tangible asset turnover were used as the measured variables of investment effect. As the result of data analysis, it was identified that the tangible asset like the hospitals's facilities and equipment was not an agent significantly to influence on the management performance(EBIT rate), the eventual goal of hospital management. But, it was identified that there was some differences tangible asset turnover according to each hospital's main characteristics. And at targeting the all sample hospitals, it was found that the management performance(EBIT rate) had some significant effect on the retained earnings rate, a part of source of PEFR.

• Journal of the Korean Home Economics Association
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• v.44 no.8
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• pp.33-45
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• 2006

The main purpose of the current research was to examine the married women's "Family Multifactor Leadership Questionnaire I" which is a new strategy for developing the strength of family. The survey was conducted with three hundred married women who have a child or children attending elementary school, based upon relationship. The main results of the present study are as following. First, the level of the married women's "Family Multifactor Leadership Questionnaire I" tended to be relatively high and they were good at charismatic leadership among sub-dimension of "Family Multifactor Leadership Questionnaire I". Moreover, internal and external controllability and social support turned out to be most influential background variables. Second, the score for the strengths of family that is recognized by the married women appeared to be more than average. It seemed that internal and external controllability, social support, and monthly gross family income were the most influential variables. Indeed, the result of stepwise regression analysis showed that transformational leadership made a comparatively high contribution to the married women's strength of family. Therefore, it is important to keep in mind that married women's leadership development is a main source of maintaining healthy family.

• Journal of Navigation and Port Research
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• v.27 no.2
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• pp.193-198
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• 2003

The slew motion of a single point moored ship by the external forces is considered to control itself. The maneuvering equations of motion are derived to express the motion of a ship. The wind forces and the wave forces are considered as the external forces of the single point moored ship in the simulation. The wave forces in the time domain analysis are generated from the frequency transfer function calculated by 3-D source distribution method. The wind forces are used the results from OCIMF(1994). To control the slew motion, the bow thruster and the bridle anchoring with 2nd anchor are used in the numerical simulation.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.527-530
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• 2010

A performance test of an air cycle machine with an air to air heat exchanger was performed. The air cycle machine designed for avionics cooling in a fighter's external pod is a small turbo machine operated on the reverse Brayton air cycle driven by captured ram air which is the source of driving energy and it can be used as cooling fluid going through electronics in the pod during the flight. The air to air heat exchanger was also used to avoid moisture for avionics. The performance test have verified that the developed ACM and heat exchanger meet the design requirements.

• Structural Engineering and Mechanics
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• v.42 no.1
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• pp.25-38
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• 2012

Recently, investigated failures of external post-tensioned (PT) tendons have called attention to the corrosion of strands in PT bridges, and the prevention of ongoing corrosion is required to secure their structural integrity. Since voids inside ducts can be a source for the ingress of water or deleterious chemicals, the vacuum grouting (VG) method and a volumeter for estimating amount of repair grouts were employed to fill voided ducts. However, the VG method is expensive and time-consuming for infield application because it requires an air-tight condition of entire ducts. Thus, latest research assessed three different repair grouting methods, and the pressure vacuum grouting (PVG) method was recommended in the field because it showed good filling capability in voided ducts and did not require an air-tight condition. Thus, a new method is required to estimate the volume of repair grouts because the PVG method is not applied in air-tight ducts. This research assesses the relationship between voided areas on ducts identified with soundings and required grout volume for repair using experimental results. The results show that the proposed equations and assumptions for estimating repair grout volume provide a sufficient amount of repair grouts for filling voided ducts.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.05a
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• pp.330-334
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• 2004

In this paper, we studied on the fire dispersive patterns and the fire progress at the power cord sets for low voltage appliances in the wall-model. For the experiment, we manufactured a wall-model and applied the external flame at the power cord sets. From the results, short-circuit of the power cord sets was haunted by the external flame it was disconnected with the flashing and the scattering. The fire progress on the polyvinyl chloride insulated flexibel cords is not observed because the ignition energy decreases. In case of rubber insulated flexible cords, however, the fire was progressed continuously. Molten marks were formed at a two electric wire by continuous electric discharge in power source part. A large molten mark was formed in load part. And the columnar structure and voids were observed in molten wire.

• Proceedings of the KIEE Conference
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• 2004.05b
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• pp.132-135
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• 2004

In generally, compared with VHF band, electromagnetic waves of UHF band have a low influence for external noise. We can detect the real abnormality with several pC in GIS using UHF method. Recently, it has applied to use the external UHF sensor attached on spacer to GIS of existing substation. In this paper, we firstly described the technique of the partial discharge measurement using frequency analysis and phase analysis in UHF band. Secondly, we presented the results of sensitivity, the relationship of dBm-pC and diagnosis of the reason of PD source by phase analysis. And then, we report the diagnosis result of partial discharge on 800kV GIS in domestic substation. rge diagnosis of GIS.

• Journal of Sensor Science and Technology
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• v.14 no.5
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• pp.337-342
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• 2005

A silicon-based micro-reactor to amplify small amount of deoxyribonucleic acid (DNA) has been fabricated using micro-electro-mechanical systems (MEMS) technology. Polymerase chain reaction (PCR) of DNA requires a precise and rapid temperature control. A Pt sensor is integrated directly in the chamber for real-time temperature measurement and an infrared lamp is used as external heating source for non-contact and rapid heating. In addition to the real-time temperature sensing, PCR needs a rapid thermocycling for effective PCR. For a fast thermal response, the thermal mass of the reactor chamber is minimized by removal of bulk silicon volume around the reactor using double-side KOH etching. The transparent optical property of silicon in the infrared wavelength range provides an efficient absorption of thermal energy into the reacting sample without being absorbed by silicon reactor chamber. It is confirmed that the fabricated micro-reactor could be heated up in less than 30 sec to the denaturation temperature by the external infrared lamp and cooled down in 30 sec to the annealing temperature by passive cooling.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.3
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• pp.10-17
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• 2005

An experimental study was conducted at a Mach number of 2.0 to investigate the buzz suppression method on an axisymmetric, external compression supersonic inlet. The inlet model has a fixed geometry with no internal contraction. The inlet configuration was altered by changing the cowling. Results show that source of buzz has been related to the existence in the flow field of velocity discontinuity across a vortex sheet which originates from a shock intersection point. With external compression inlet, buzz can be suppressed by positioning the oblique shock slightly inside or outside of the cowl.