• Membrane and Water Treatment
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• 제9권5호
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• pp.293-300
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• 2018

The removal of volatile organic compounds (VOCs) from water using KOH-activated pine tree needle leaves biochar is considered a cost effective and efficient process. In this study, pine tree needle leaves were mixed with 0, 50, 100 and 200% (KOH weight/feedstock weight) of KOH, respectively. Then, the mixture was pyrolyzed at $500^{\circ}C$ for 6 hrs. The adsorption characteristics of 10 VOCs to the biochar were tested. The results indicated that the removal efficiency of the KOH activated biochar was highest in 100% KOH-biochar. The VOC removal efficiencies of 50% and 200% KOH activated biochar were similar and the 0% KOH activated biochar showed the lowest VOC removal. The FTIR results showed that increasing the amount of KOH seemed to enhance the formation of various functional groups, such as -OH, -C=C, -O. The adsorption strength of 10 VOCs to the KOH activated biochar seemed to be increasing by the increase of the solubility of VOCs. This may suggest that the adsorption is taking place in hydrophilic sites of the biochar surface. The KOH activated pine tree needle leaves biochar can be an effective sorbent for VOCs removal in water and 100% KOH mixing seemed to provide better sorption capacity.

• 대한기관식도과학회지
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• 제7권1호
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• pp.14-18
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• 2001

Background and Objectives： Vegetable Foreign bodies (VFB) in the bronchial tree may be complicated by fragmentation, slippage and impaction during the removal with forceps. This study is to evaluate the safety and efficacy for the technique of removing VFB from the bronchial tree in infants and early childhood using Fogarty balloon catheter. Materials and methods : The subjects consisted of 18 infants and early childhood (7-22 months old) with VFB in the bronchial tree from January 1991 through October 1998. The authors first attempted removal of VFB with forceps and if that failed, removed VFB with Fogarty arterial embolectomy catheter under the ventilating bronchoscopy and general anesthesia. Results: We removed 6 VFB with forceps. could not remove anymore, and so removed 12 VFB with Fogarty catheter. In 8 VFB of less than 24 hours, we could remove 6 VFB with forceps and 2 VFB which could not be removed with forceps were removed with Fogarty catheter. In 10 VFB of more than 24 hours, we could not remove with forceps and removed with Fogarty catheter. Conclusions : VFB in the bronchial tree of infants and early childhood can usually be removed with forceps. But we think that Fogarty balloon catheter technique is a easy, safe method for the removal of bronchial VFB of more than 24 hours, fragmentation, impaction, lower bronchus and too round or slippery to remove with forceps in infants and early childhood.

• Environmental Engineering Research
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• 제21권2호
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• pp.152-163
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• 2016

Present study investigates the potential of cassava peel and rubber tree bark for the removal of Cr (VI) from aqueous solution. Removal efficiency of more than 99% was obtained during the kinetic adsorption experiments with dosage of 3.5 g/L for cassava peel and 8 g/L for rubber tree bark. By comparing popular isotherm models and kinetic models for evaluating the kinetics of mass transfer, it was observed that Redlich-Peterson model and Langmuir model fitted well ($R^2$ > 0.99) resulting in maximum adsorption capacity as 79.37 mg/g and 43.86 mg/g for cassava peel and rubber tree bark respectively. Validation of pseudo-second order model and Elovich model indicated the possibility of chemisorption being the rate limiting step. The multi-linearity in the diffusion model was further addressed using multi-sites models (two-site series interface (TSSI) and two-site parallel interface (TSPI) models). Considering the influence of interface properties on the kinetic nature of sorption, TSSI model resulted in low mass transfer rate (5% for cassava peel and 10% for rubber tree bark) compared to TSPI model. The study highlights the employability of two-site sorption model for simultaneous representation of different stages of kinetic sorption for finding the rate-limiting process, compared to the separate equilibrium and kinetic modeling attempts.

• 원예과학기술지
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• 제33권1호
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• pp.106-113
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• 2015

Effects of mineral salts (N, P, K, $Ca^{2+}$, $Mg^{2+}$, and $Fe^{3+}$) on the shoot growth and metabolite production of tea tree were studied using in vitro culture techniques. Among mineral s alts, ${H_2PO_4}^-$ was the most important for enhanced growth rate of tea tree, while $Mg^{2+}$ and $Ca^{2+}$ did not affect plant growth. Removal of ${NH_4}^+$ and $NO_3$ from the culture medium enhanced shoot multiplication compared to other treatments. Metabolite production was variable depending on mineral types and concentration. Removal of $Ca^{2+}$ decreased the production of caffeine; however, other treatments did not influence its production. $Ca^{2+}$, ${NH_4}^+$ and $Fe^{3+}$ were important factors for catechin production in tea tree. These results can be used as the basis for development of technical soil controls suitable for tea tree cultivation in the future.

• 한국안전학회지
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• 제35권1호
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• pp.97-106
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• 2020

The objective of this paper is to suggest a new quantification method for multi-unit probabilistic safety assessment (PSA) that removes the overestimation error caused by the existing delete-term approximation (DTA) based quantification method. So far, for the actual plant PSA model quantification, a fault tree with negates have been solved by the DTA method. It is well known that the DTA method induces overestimated core damage frequency (CDF) of nuclear power plant (NPP). If a PSA fault tree has negates and non-rare events, the overestimation in CDF drastically increases. Since multi-unit seismic PSA model has plant level negates and many non-rare events in the fault tree, it should be very carefully quantified in order to avoid CDF overestimation. Multi-unit PSA fault tree has normal gates and negates that represent each NPP status. The NPP status means core damage or non-core damage state of individual NPPs. The non-core damage state of a NPP is modeled in the fault tree by using a negate (a NOT gate). Authors reviewed and compared (1) quantification methods that generate exact or approximate Boolean solutions from a fault tree, (2) DTA method generating approximate Boolean solution by solving negates in a fault tree, and (3) probability calculation methods from the Boolean solutions generated by exact quantification methods or DTA method. Based on the review and comparison, a new intersection removal by probability (IRBP) method is suggested in this study for the multi-unit PSA. If the IRBP method is adopted, multi-unit PSA fault tree can be quantified without the overestimation error that is caused by the direct application of DTA method. That is, the extremely overestimated CDF can be avoided and accurate CDF can be calculated by using the IRBP method. The accuracy of the IRBP method was validated by simple multi-unit PSA models. The necessity of the IRBP method was demonstrated by the actual plant multi-unit seismic PSA models.

• 한국전통조경학회지
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• 제29권4호
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• pp.78-86
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• 2011

산성의 복원과정에서 조망 확보를 위해 산림경관에 대한 정비가 요구된다. 본 연구에서 산성에 대한 조망 확보를 위한 산림경관 관리방안이 제시되었다. 관리방안의 검증을 위해 GIS를 이용한 시곡면과 누적가시도 분석이 이용되었다. 경주 명활산성에 대해 경관 분석과 산림정비계획 수립, 수목 제거사업 등의 결과가 비교되었다. 연구결과는 다음과 같다. 첫째, 외부의 주요 조망점에서 명활산성에 대한 누적가시도 분석을 시행하였다. 분석결과를 활용하여 산성에서 우수가시구간의 선정이 가능하였다. 6개의 우수가시구간은 총 길이가 1,937m(전체 구간의 41.2%)이다. 둘째, 우수가 시구간에 대해 수목의 평균높이와 우점종인 소나무의 최대 성장높이를 반영한 시곡면 분석을 비교하였다. 비교결과, 수목의 평균높이를 반영하는 것이 최대 성장높이를 반영한 것보다 식생에 대한 훼손을 최소화하면서 산성의 가시성을 확보하는데 효과가 있을 것으로 판단되었다. 셋째, 도출된 정비구역 중에서 가시빈도가 높은 A구역이 타당성 검토를 위해 선정되었다. 주요 조망점에서의 가시 여부를 검토하면서 A구역에 대한 수목 제거작업이 수행되었다. 비교결과, 정비계획($10,935m^2$)과 제거지역($11,296m^2$)은 미미한 차이(3.3%)가 발생하였다. 이를 통해 산성 주변의 산림경관 정비를 위한 누적가시도와 시곡면 분석법의 효용성이 검증되었다.

• Advances in environmental research
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• 제7권3호
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• pp.225-237
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• 2018

The sorption of metal ions with low-cost adsorbents plays an important role in sustainable development. In the present study, the efficacy of sugarcane bagasse, rain tree fruits (samaneasaman), banana stem and their mixtures, used as bio-sorbents, in the removal of Cu(II) and Pb(II) ions from aqueous solution is evaluated. Batch studies are conducted, and residual ions were measured using Inductively Coupled Plasma (ICP)-atomic spectrometer. Effect of pH, initial metal ion concentration, reaction time and adsorbent dosage are studied. The Pb(II) removal efficiency was observed to be 97.88%, 98.60% and 91.74% for rain tree fruits, banana stem and a mixture of adsorbents respectively. The highest Cu(II) ion removal was observed for sugarcane bagasse sorbent with an efficiency of 82.10% with a pH of 4.5 and a reaction time of 90 min. Finally, desorption studies were carried out to study the leaching potential of adsorbent, and it was found that the adsorbent is stable in water than the other leaching agents such as HCl, ammonium acetate, Sodium EDTA. Hence, these adsorbents can be effectively used for the removal of these heavy metals.

• 전자공학회논문지A
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• 제28A권5호
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• pp.398-406
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• 1991

This paper presents a graphics accelerator for fast image generation. The accelarator has three major functional blocks: linear interpolator, multipliers and Edgee Painting Tree. Linear interpolator with coupled binary tree structure interpolates functional values of two end points. Two multipliers compute input values of interpolator in parallel. Mask pattern which removes out invalid data is generated by Edge Painting Tree. The proposed architecture in this paper is responsible for 64 pixels and can process about 5,900 10x10polygons per second.

• 한국자원식물학회지
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• 제13권1호
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• pp.48-53
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• 2000

옻나무 묘목대량증식법의 하나로 조직배양 방법을 이용하여 기내 유식물체를 다량으로 증식함으로써 옻나무 증식의 효율성을 높이기 위하여 기내 무균묘를 얻고자 실시하였다. 비중 1.0으로 선종한 결과 1차선종은 평균 50.7%의 선종율을 보였고, 98% sulfuric acid에 2시간 교반 후 2차로 선종한 결과 선종율은 20.8%였다. 발근율은 외종피를 함유한 종자(5.4%) 보다는 외종피를 제거하거나(18.3%) 내종피를 제거한 종자(32.4%)가 높았다. 전처리에 따른 종자의 발아율은 생장조절물질 처리에 의한 효과가 인정되지 않았으며, 각 처리별 유의수준도 인정되지 않았으나 sulfuric acid를 처리했을 경우 발아율이 3%로써 생장조절물질 처리보다는 약간 효과적인 것으로 나타났다. 외종피를 제거하면 발아율은 약간 높게 나타났는데, 생장조절물질을 첨가함으로써 약 4%정도 향상되었다. 특히 BA 1.0mg/L와 NAA 0.05mg/L의 혼용처리와 BA 1.0mg/L 단독처리가 10% 내외의 발아율을 보였다. 옻나무 종자는 배지에 치상한 후 약 10일 만에 정상적으로 발아하였고, 치상 후 약 3주만에 본엽이 출현한 정상적인 무균묘를 획득할 수 있었으나 발아율이 10%내외에 불과하여 매우 저조하였다.

• 원예과학기술지
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• 제17권3호
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• pp.329-332
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• 1999

대목재식 후 2년차에 측지가 10개 이상 발생 된 우량묘를 생산하기 위하여 삭아접시기 및 대목 절단시기에 따른 수체생육 특성과 측지발생에 미치는 적엽 및 promalin 처리 효과를 시험한 결과, 대목재식 후 약 90일 정도 경과한 6월중순경에 삭아접을 실시하는 것이 4월 중순에 삭아접을 하는 것보다 재식 1년차의 수체생육은 떨어지지만 접아고사주율이 평균 8% 정도 낮았다. 또한 M.9 대목 절단시기에 있어서는 삭아접전절단(ECCB)을 실시하는 것보다 삭아 접후절단을 할 경우, 접아고사율이 14% 정도 낮아 수체 생장의 균일도가 높으면서 접목효율이 높은 것으로 나타났다. 재식 2년차인 1998 년도에 접목시기 및 M.9 대목 절단시기에 따른 적엽(3회) 및 promalin(3회) 처리효과를 조사한 결과, 6월 중순 삭아접후절단(LCCB) 처리 구에서 측지발생 효과 및 화아형성 정도가 다른 처리에 비하여 가장 좋았다. 묘목 특성으로는 수고 209cm, 측지수 13.8개, 화아형성수 9.0개로 우량한 측지묘 조건에 부합한 묘목이 생산되었다.