• 한국안전학회지
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• 제29권4호
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• pp.61-72
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• 2014

The aim of this study is to define the condition of optimal pre-treatment for preferable activated carbon fibers (ACFs), which are based on rayon fibers. This paper shows the ideal path of ACFs preparation process; implies that rayon fibers are pre-treated by various solvents with different times before the heating process. The pre-treated rayon fibers finally turned into desirable rayon fiber-based ACFs through optimal pre-treatment condition by heating processes. The thermal analysis method of pre-treated rayon fibers by thermo-gravimetry analyser (TGA) is an idealized tool, which analyzes the best thermal condition of pre-treatment process. Surface morphologies of resulting rayon fibers based ACFs were examined by scanning electron microscope(SEM). The results of TGA and SEM analyses show that the optimal pre-treatment condition for preparing ACFs was clearly defined, in terms of thermal stability and surface morphology.

• 한국초등과학교육학회지:초등과학교육
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• 제35권2호
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• pp.216-228
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• 2016

The purpose of this study was to analyze pre-school teachers' observation experience and their pre and post degrees of preferences in observing underground and water living things, fungus, insects, flowerless plants and sea lives. Based on the analysis, their pre-observation experience in living things were insects, ocean creatures, underground living things, flowerless plants, fungus and water living things in order. The degree of preferences in flowerless plans based on their gender, the female pre-service teachers showed higher scores than the average in both pre and post test. The male, however, responded higher scores in underground living things in both tests. Their background such as liberal arts or science or arts and physical major affected their preferences scores in water living things, insects and flowerless plans in the post test, and the science major pre-service teachers showed the highest degree of preferences in insects among the liberal arts, science or arts and physical major pre-teachers in the post test. In conclusion, there were different degree of their preferences affected by the pre observation experience, gender difference, their present majors such as the liberal arts, science or arts and physical major, the categories of living things but not in their high school background such as liberal arts or science.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2003년도 학술대회지
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• pp.481-484
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• 2003

최근의 건설사업에서는 전체 건설공사 수행과정 중 특히 Pre-con 단계의 중요성이 점차 커지고 있으며 Project 성패에도 큰 영향을 미치고 있다. 그러나 현재 우리나라 건설사업은 Pre-con 단계에 대한 정확한 개념 및 체계화가 이루어지지 않고 있으며 대부분 현장소장의 경험에 의존하고 있기 때문에 체계적인 공사수행에 차질을 빚는 등 많은 문제점이 나타나고 있다. 이에 본 연구를 통해 전체 Pre-con 단계 중 종합건설회사내에서 시공계획서작성이전 Pre-con 단계의 업무흐름을 분석하고 업무부서간의 도식화된 업무체계를 제시하고자 한다. 이를 통해 불필요한 업무론 배제하고 더 나아가 향상된 업무 흐름을 통해 체계적인 공사계획을 수립하여 본 공사에서의 효율성 향상을 기대할 수 있을 것이다.

• Environmental Engineering Research
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• 제19권1호
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• pp.59-66
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• 2014

The aim of this study was to assess the effect of pre-aeration on sludge solubilization and the behaviors of nitrogen, dissolved sulfide, sulfate, and siloxane. The results of this study showed that soluble chemical oxygen demand in sewage sludge could be increased through pre-aeration. The pre-aeration process resulted in a higher methane yield compared to the anaerobic condition (blank). The pre-aeration of sewage sludge, therefore, was shown to be an effective method for enhancing the digestibility of the sewage sludge. In addition, this result confirms that the pre-aeration of sewage sludge prior to its anaerobic digestion accelerates the growth of methanogenic bacteria. Removal rates for $NH_3$-N and T-N increased simultaneously during pre-aeration, indicating simultaneous nitrification and denitrification. The siloxane concentration in sewage sludge decreased by 40% after 96 hr of pre-aeration; in contrast, the sulfide concentration in sewage sludge did not change. Therefore, pre-aeration can be employed as an efficient treatment option to achieve higher methane yield and lower siloxane concentration in sewage sludge. In addition, reduction of nitrogen loading by pre-aeration can reduce operating costs to achieve better effluent water quality in wastewater treatment plant and benefit the anaerobic process by minimizing the toxic effect of ammonia.

• 한국위성정보통신학회논문지
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• 제12권2호
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• pp.104-111
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• 2017

복수의 안테나를 사용하는 Pre-Rake CDMA 시스템은 복잡한 RAKE 합성기를 수신기에서 사용하지 않아도 좋은 수신 성능을 얻을 수 있는 장점이 있다. 그러나 Pre-Rake 시스템은 채널 추정오류에 크게 영향을 받기 때문에 시스템 성능 평가에 있어서 채널추정 오류는 반드시 고려되어야 한다고 볼 수 있다. 본 논문에서는 채널추정오류를 가지는 MISO Pre-Rake CDMA 시스템을 이론적인 해석을 통하여 분석한 후 도출된 결과를 컴퓨터 시뮬레이션을 이용해 얻은 결과와 비교한다. 이론적인 해석결과로 볼 때, Pre-Rake 시스템의 성능은 진폭오류 보다는 위상오류에 의한 영향을 크게 받는 것으로 확인되었다.

• Animal cells and systems
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• 제11권2호
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• pp.129-134
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• 2007

The initiation of eukaryotic DNA replication requires assembly of the pre-replicative complex (Pre-RC) through the concerted action of Orc, Cdc6, Cdt1 and Mcm2-7 complex during G1 phase. The pre-RC assembly licenses individual replication origins for the initiation of DNA replication and sufficient number of the pre-RC is essential for proper progression of S phase. However, it is not well known how cells recognize the completion of the pre-RC assembly before G1-S transition. In order to understand the cellular responses to the defects in pre-RC assembly, we depleted the known components of pre-RC proteins using the small interference RNAs in HeLa cells. Although the defects of pre-RC assembly by the depletion of the pre-RC proteins such as Orc2, Cdt1, Mcm2 & Mcm10 did not elicit the activation of Chk1- or Chk2-dependent checkpoint pathways, these cells still showed significant decrease in the cellular level of Cdc25A proteins. These results suggests that a novel checkpoint pathway exist in HeLa cells, which is not dependent upon Chk1 or Chk2 proteins and play essential roles in the cellular responses to the defects in the pre-RC assembly. Also, among those four proteins tested in this study, the depletion of Mcm10 and Cdt1 proteins significantly increased the apoptotic cell death in HeLa cells, suggesting that these proteins not only play roles in the pre-RC assembly, but also are involved in the checkpoint responses to the defects in the pre-RC assembly.

• The Plant Pathology Journal
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• 제23권3호
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• pp.203-209
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• 2007

Infection structures were observed using a fluorescence microscope at the penetration sites on the leaves of potato plants pre-inoculated with the bacterial strains Pseudomonas putida TRL2-3, Micrococcus luteus TRK2-2, and Flexibacteraceae bacterium MRL412, which mediated an induced systemic resistance on potato plants against late blight disease caused by Phytophthora infestans. In order to compare the infection structures on the leaves expressing systemic acquired resistance, the leaves of potato plants pre-treated with DL-3-amino butyric acid (BABA) were also observed after challenge inoculation with the same pathogen. The infection structures were investigated. The total number of germination and appressorium formation of P. infestans were counted. Furthermore, the frequencies of fluorescent epidermal cells at the penetration sites, which indicate a defense response of plant cell, were estimated. There were no differences on the germination rates of the fungal cysts among the untreated control, BABA pre-treated, and bacterial strains pre-inoculated plants. However, appressorium formation was slightly decreased on the leaves of BABA pre-treated plants compared to those of untreated as well as bacterial strains pre-inoculated plants. Furthermore, the frequencies of fluorescent cells of BABA pre-treated and bacterial strains pre-inoculated were higher than that of untreated plants, indicating an active defense reaction of the host cells against the fungal attack. On the other hand, the pre-treatment with BABA caused a stronger fluorescent of epidermal cells at the penetration sites compared to the pre-inoculation with the bacterial strains. Interestingly, the frequency of fluorescent cells by BABA, however, was lower than that by the bacterial strains. Based on the results it is suggested that the infection structures showing resistance reaction on the leaves of potato plants were different between by pre-inoculation with bacterial strains and by pre-treatment with BABA against the late blight pathogen.

• 한국비블리아학회지
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• 제29권1호
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• pp.253-275
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• 2018

이 연구는 예비사서들의 도서관실습 교육을 지원하기 위한 '사전교육 프로그램'을 개발하고 그 운영방안을 제언하는 것을 목적으로 한다. 사전교육 프로그램 내용과 운영방법을 구상하기 위해 관련 선행연구를 종합적으로 분석하고, 실습참가자들의 사전 요구들을 분석하여 최종 사전교육 내용구성과 운영방법을 제안하였다. 5가지 교육주제와 세부항목들로 구성된 사전교육 프로그램을 실제로 도서관실습에 참여하려는 H대학의 문헌정보학과 학생들을 대상으로 교육을 실시하였다. 사전교육 직후 설문지법과 포커스 그룹 인터뷰를 통해 프로그램의 내용과 운영방법에 대한 만족도 조사를 실시하였다. 그 결과, 예비사서들은 교육 중 '커뮤니케이션 스킬 개발'에 대한 내용에 가장 큰 만족도와 선호를 보였고, '이력서 및 자기소개서 작성', '자아성찰 및 자기설계' 순서였다. 교육내용에 대한 사전요구와 만족도는 실습참여자들의 인구학적 특성인, 학업성적, 진로결정 유무 등에 따라 다른 선호도를 표하는 바, 사전교육을 실행함에 있어 일괄적 교육보다는 실습참여자들의 특성을 고려하여 사전교육 내용을 선택적이고도 융통성 있게 조합하여 운영할 것을 제언하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제32권12호
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• pp.1844-1853
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• 2019

Objective: We investigated how pituitary adenylate cyclase-activating polypeptide (PACAP) affects embryonic development during pre-in vitro maturation (pre-IVM) using porcine oocytes isolated from small follicles. Methods: We divided the follicles into the experimental groups by size (SF, small follicles; MF, medium follicles) and treated with and without PACAP and cultured for 18 hours (PreSF[-]PACAP; without PACAP, Pre-SF[+]PACAP; with PACAP) before undergoing IVM. The gene expression related to extracellular matrix formation (amphiregulin, epiregulin, and hyaluronan synthase 2 [HAS2]) and apoptosis (Bcl-2-associated X [BAX], B-cell lymphoma 2, and cysteine-aspartic acid protease 3) was investigated after maturation. The impact on developmental competence was assessed by the cleavage and blastocyst rate and total cell number of blastocysts in embryos generated from parthenogenesis (PA) and in vitro fertilization (IVF). Results: Cleavage rates in the Pre-SF(+)PACAP after PA were significantly higher than SF and Pre-SF(-)PACAP (p<0.05). The cleavage rates between MF and Pre- SF(+)PACAP groups yielded no notable differences after IVF. Pre-SF(+)PACAP displayed the higher rate of blastocyst formation and greater total cell number than SF and Pre-SF(-)PACAP (p<0.05). Cumulus cells showed significant upregulation of HAS2 mRNA in the Pre-SF(+)PACAP compared to the SF (p<0.05). In comparison to other groups, the Pre-SF(+)PACAP group displayed a downregulation in mRNA expression of BAX in matured oocytes (p<0.05). Conclusion: The PACAP treatment during pre-IVM improved the developmental potential of porcine oocytes derived from SF by regulating cumulus expansion and apoptosis of oocytes.

• Steel and Composite Structures
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• 제20권4호
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• pp.833-849
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• 2016

Pre-stressing of existing structures using steel cables, FRP cables or FRP laminates has been successfully tried in the past. Retrofitting of beams using pre-stressed laminates does not utilize the full strength of the FRP due to de-bonding of the laminates before the fibre fracture. In the present study attempt has been made to overcome this problem by replacing the FRP laminates by the FRP sheets. In the present paper the effect of initial damage level and pre-stress level on strength, stiffness, cracking behaviour and failure mode of girders retrofitted using pre-stressed CFRP sheets has been studied. The results indicate that rehabilitation of initially damaged girders by bonding pre-stressed CFRP sheets improves the flexural behaviour of beams appreciably. However, it has been observed that with increase in pre-stressing force the load carrying capacity of the girders increases up to a particular level up to which the mode of failure is fibre fracture. Thereafter, the mode of failure shifts from fibre fracture to de-bonding and there is no appreciable increase in load carrying capacity with further increase in pre-stressing force.