• 분석과학
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• 제5권4호
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• pp.381-387
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• 1992

액체섬광계수법을 방사성탄소 연대측정에 이용하기 위하여 섬광용액과 섬광용액 대 벤젠의 부피비, 그리고 베타선 스펙트럼 측정범위를 변화시키면서 삼중수소의 영향을 최소화하고 최대 FOM을 얻기 위한 저준위 액체섬광계수기의 최적계측조건을 결정하였다. 결정된 조건하에서 백그라운드 계수율을 $2.26{\pm}0.03cpm$ 까지 낮출 수 있었으며, 이때의 최대 측정가능 연대는 약 40,000년에 이르렀다. 또한 고개시료 및 토탄시료 등의 실제시료에 적용하여 측정계의 실용성을 확인하였다.

• 한국환경과학회지
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• 제16권11호
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• pp.1279-1285
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• 2007

The activated carbon was prepared from waste citrus peels using NaOH. With the increase of NaOH ratio, iodine adsorptivity and specific surface area of the activated carbon prepared were increased, but activation yield was decreased. The optimal condition of activation was at 300% NaOH and $700^{\circ}C$ for 1.5 hr. For the activated carbon produced under optimal condition, iodine adsorptivity was 1,006 mg/g, specific surface area was $1,356 m^2/g$, and average pore diameter was $20{\sim}25{\AA}$. From the adsorption experiment for benzene vapor in fixed bed reactor, it was found that the adsorption capacity of activated carbon prepared from waste citrus peel was higher than that of activated carbon purchased from Calgon company. This result implied that the activated carbon prepared from waste citrus peel could be used for gas phase adsorption.

• 한국농촌건축학회논문집
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• 제10권2호
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• pp.45-52
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• 2008

The purpose of this study is to clarify the actual condition of the road station in japan. The thorough investigation and observation works were made from the view points of the location and service facilities of the road station in kanto area. This article discusses about the basic characteristics of the road stations and actual condition of service facilities of 126 road stations in kanto area. The results of this study are summarized as follows; The main patterns of the site by locational conditions are classified in five types. Those are mountain district type, traffic point type, urban district type, riverside type and seaside type. In planning of road stations, locational condition and regional difference of public facilities are crucial factors.

• 한국언어정보학회지:언어와정보
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• 제6권2호
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• pp.153-169
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• 2002

In this paper I develop a mechanism of interpreting Korean “wh-phrases”. The phrases have various readings depending on where they occur and they could be ambiguous even in the same structure. Yet their readings are subject to certain restrictions. I assume that the “wh-phrases” behave like variables and that there are three quantifiers to bind the phrases; $COMP_{wh},\;COMP_{conc}$ and derivational $\exists$-quantifier. Based on the assumptions I suggest derivational quantification, which consists of three conditions. 1) A quantifier can bind only when it merges into the derivation; 2) $\exists$-quantifier accompanies 〔-OP〕 complementizer but its activation is optional; 3) an instance of quantification makes the clause opaque to other instances of quantification. Scrambling data support derivational approach and across-the-board interpretation motivates the opacity condition. The opacity condition accounts for ATB- interpretations of reflexive pronouns. It can also explain the island effect of wh-islands without adopting covert wh-movement in Korean.

• 한국환경과학회지
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• 제24권12호
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• pp.1601-1608
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• 2015

This study evaluates heavy metal(Cu and Cr) adsorption characteristics produced from food waste charcoal extracted in an optimal operation condition after analyzing activated charcoal of iodine adsorption and heavy metals that derived from an activation process of carbide by the developed by-products of food waste treatment facility using the methods from previous studies. As experiment apparatus, this study used a tube-shaped high temp furnace. The mixing ratio of by-products of food waste treatment facility, carbide, and activation component($ZnCl_2$) was 1:1. The experiment was proceeded as adjusting the activation temperature from 400 to $800^{\circ}C$ and activation time from 30 to 120 minutes. The optimal activation condition for iodine absorption was 90 minutes at $700^{\circ}C$ and by using the produced food waste charcoal, this study conducted an experiment on absorption of heavy metals (Cu and Cr) as changing pH of artificial wastewater and stirring time. As a result, pH 7 showed the highest heavy metal decontamination ratio and in terms of stirring time, it revealed balance adsorption after 10 minutes. This result can be particularly applied as basic data for recyclability of high concentration organic waste, by-products of food waste treatment facility, as an food waste charcoal.

• The Journal of Korean Physical Therapy
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• 제25권6호
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• pp.393-398
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• 2013

Purpose: The purpose of this study was to compare muscle activation patterns of lower extremities in stroke patients during stepper climbing, stair-up, and level-ground gait conditions by surface electromyography (EMG). Methods: Subjects included 19 hemiplegic patients comprehensive rehabilitation center for inpatients with stroke. Surface EMG was used to measure the subjects' medial gastrocnemius (GCM), tibialis anterior (TA), biceps femoris (BF), and rectus femoris (RF) activity as they took six steps during stepper climbing, stair-up, and level-ground gait conditions. Results: There was no significant difference in the BF or RF muscle activity for the stepper climbing, stair-up, and level-ground gait conditions. However, there were significant differences in the medial GCM and TA muscle activity between each condition on the patients' hemiplegic side(p<0.05). There was significant difference in the medial GCM, TA, RF, and BF muscle activity between each condition on the patients' non-hemiplegic side (p<0.05). Conclusion: As a result, the overall muscle activity during the level-ground gait was higher than the stair-up condition, and the muscle activity during the stair-up condition was higher than the muscle activity during the stepper climbing condition. As one of the many methods used for gait training, we suggest that the stepper exercise could be applied at an earlier stage in the gait training process.

• Preventive Nutrition and Food Science
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• 제12권4호
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• pp.251-258
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• 2007

Thermal resistance and heat activation characteristics of Clostridium botulinum ATCC 25763 spores were evaluated. The effects of nisin and pH on the activation and subsequent germination were also investigated. Spores of C. botulinum were not inactivated by heat treatments up to $92^{\circ}C$ for 2 hr. Heat treatment at $85^{\circ}C$ for 90 min was selected as the optimal activation condition based on monitoring subsequent germination. L-alanine alone or in combination with L-cysteine was not sufficient to germinate the spores of this strain. Tryptone-Peptone- Glucose-Yeast extract (TPGY) broth supplemented with L-alanine was used as a suitable germination medium. Decreasing pH of activation suspension increased the degree of phase darkening, i.e., germination. In addition, the presence of nisin during activation increased the degree of phase darkening. The majority of spore populations were dormant at a pH of less than 2.8, and these populations required heat activation to increase the culturability on TPGY agar medium. However, extended heating in the presence of nisin at pH 2.8 decreased the spore count; however, heat activation was less necessary at pH 3.4, compared at pH 2.8.

• 대한의용생체공학회:의공학회지
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• 제43권1호
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• pp.52-60
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• 2022

Purpose: For now, cognitive load is assessed based on survey-based methods, which can be difficult to track the amount of cognitive load in real-time. In this study, we investigated the difference in electrophysiological activation due to different levels of cognitive load not only at sensor-level but also at source-level using electroencephalogram that might be potentially used for quantitative cognitive load evaluation. Materials and Methods: In this study, ten healthy subjects (mean age 24.3 ± 2.1, three female) participated the experiment. All participants performed 4 sessions of n-back task in different difficulties: 0-, 1-, 2-, and 3-back during electroencephalogram recording. For sensor-level analysis, we calculated the event-related potential and event-related spectral perturbation while low resolution brain electromagnetic tomography (LORETA) to estimate the source activation. Each result was compared between different workload conditions using statistical analysis. Results: Statistical results revealed that the accuracy of the task performance was significantly different between different cognitive loads (p = 0.018). The post-hoc analysis confirmed that the accuracy of the 3-back task was significantly decreased compared to 1-back condition (p = 0.018), but not with 2-back condition (p = 0.180). ERP results showed that P300 target amplitude between 1-back and 3-back had a marginal difference in Cz (p = 0.059) and Pz(p = 0.093). A significant inhibition in Cz high-beta activation (p = 0.017) and decrease in source activation of right parahippocampal gyrus was found in 3-back condition compared to 1-back condition (p < 0.05). Conclusion: In this study, we compared the sensor- and source-level differences in electroencephalogram between different levels of cognitive load, that were found to be in line with the previous reports related to cognitive load evaluation. We expect that the outcome of the current study can be used as a feature to establish a quantitative cognitive load assessment system.

• Korea-Australia Rheology Journal
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• 제21권2호
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• pp.135-141
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• 2009

Effect of activation energy and crystallization kinetics of polyethylenes (PEs) on the dynamics and stability has been investigated by changing rheological properties and crystallization rate in film casting process. The effect of changes of these properties has been shown using a typical example of short-chain branching (SCB) in linear polyethylenes. SCBs in linear polymers generally lead to the increase of the flow activation energy, and to the decrease of the crystallization rate, making polymer viscosity lower in the case of equivalent molecular weight. In general, the increment of the crystallinity of polymers under partially crystallized state helps to enhance the process stability by increasing tension, and lower fluid viscoelasticity possesses the stabilizing effect for linear polymers. It has been found that the fluid viscoelasticity plays a key role in the control of process stability than crystallization kinetics which critically depends on the cooling to stabilize the film casting process of short-chain branched polymers operated under the low aspect ratio condition.

• 한국세라믹학회지
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• 제36권6호
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• pp.577-582
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• 1999

Activated carbon fibers were prepared from stabilized PAN fibers by chemical activation using hydroxide. The variations in specific surface area amount of iodine adsorption micro-structure and pore size distribution in the activated carbon fibers after the activation process were discussed. In the chemical activation using potassium hydroxide specific surface area of about 2545m2/g and amount of iodine adsorption of 2049 mg/g were obtained at the condition of KOH/fiber ratio of 1 and 800$^{\circ}C$ Nitrogen adsorption isotherms for PAN based activated carbon fibers showed the type I in the Brunauer-Deming-Deming-Teller classification indicating the micro-pores consisting the activated fibers.