• 대한인간공학회지
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• 제23권2호
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• pp.105-120
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• 2004

With the new technology and the popularization of mobile phone. the functions and designs of mobile phone have been varied rapidly. However. based on the user's level of familiarity on mobile phone function and knowledge of information technology. the using behaviors of mobile phone. especially between the young users who are well acquainted with the latest function and technology and the over middle-aged users who are relatively not. would be quite different. A survey was conducted to investigate the various using behaviors of mobile phone in different age groups. The total number of six hundred and sixty-seven people from age seventeen to sixty participated in this study. The participants were divided into young group (age between 17 to 29) and the over middle-aged group (age between 40 to 60) to compare the difference group considered design. price. and function of the mobile phone as three important factors. on the other hand. the over middle-aged group considered quality of communication. price and ease of use as three important factors. All the respondents of the young group know how to use the text messaging function. however for the over middle-aged group. 40% of the respondents knows how to use the text messaging function. The over middle-aged group seemed mainly use the mobile phone for voice communication. however the young group had a tendency to communicate each other with short text message rather than through voice conversation. Twenty percentage of young group responded that they had an experience of pain or discomfort at the thumb. the thenar eminence area. or carpus area during pushing the mobile phone keypad. The excessive frequent use of keypad may cause the risk of repetitive strain injury (RSI). The results of this study could provide important information to understand the way of using mobile phone in different age groups. and also could be used to design and market the mobile phone.

• 대한인간공학회지
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• 제23권3호
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• pp.121-134
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• 2004

A research project was conducted to study work-related musculoskeletal disorders （MSDs） at subway train repair plant in Korea. The project was consisted of 4 main parts; education on the topics of MSDs for all workers, symptom survey, medical check-up, investigation of MSD risk factors. The result of symptom survey showed that 95.2％ of the respondents complained pains on at least one part of the body. After cross-sectional analysis of various information and risk factors, 86.8％ of respondents were considered as active health surveillance level 1 that require continuous monitoring on their symptoms and working conditions. And 57.1％ of the respondents were considered as active health surveillance level 2 that needed medical check-ups for proper medical treatment. The analysis of occupational risk factors revealed that handling of heavy object (46.15％) and repeated awkward postures (46.15％) were two most contributing risk factors for the on-set of MSD at this work site followed by static strain (7.7％), and vibration and impact (3.8％). Medical examination was performed by an industrial medicine MD on 156 workers those considered as active health surveillance level 2. The result showed that 35 workers (20.7％) were considered as MSD patient group at severe level, and 68.6 workers (68.6％) were considered as moderate group and 18 workers (10.6％) were considered minor or normal group those have no symptom.

• 한국항해항만학회지
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• 제29권10호
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• pp.871-876
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• 2005

기존의 기계적인 센서들보다 높은 민감도와 선형성을 가지는 반도체 압력 센서들은 크기가 작고 일괄공정에 의해 제작될 수 있는 반도체 공정 기술로 제작되므로 다양한 산업에서 적용되고 있다. 하지만 열과 반복적인 외부 하중은 센서의 수명에 치명적인 영향을 미치고 있고, 특히 외부에서 가해지는 열은 센서를 구성하는 구조물보다 신호를 전달하는 금속 배선의 피로 수명에 지대한 영향을 미치고 있으므로 이에 대한 영향성을 분석할 수 있는 프로세스를 확립하고, 이후 다양한 재료의 반복적인 열하중에 대한 피로 수명을 Manson & Coffin식에 따라서 평가하였다. 금속 배선의 밑단에서 피로수명이 가장 낮고, 굽힘하중은 피로 수명보다는 응력분포에 큰 영향을 미치고 있다.

• Journal of Microbiology and Biotechnology
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• 제19권2호
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• pp.113-120
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• 2009

Twenty-seven fenitrothion-degrading bacteria were isolated from different soils, and their genetic and phenotypic characteristics were investigated. Analysis of the 16S rDNA sequence showed that the isolates were related to members of the genera Burkholderia, Pseudomonas, Sphingomonas, Cupriavidus, Corynebacterium, and Arthrobacter. Among the 27 isolates, 12 different chromosomal DNA fingerprinting patterns were obtained by polymerase chain reaction(PCR) amplification of repetitive extra genic palindromic(REP) sequences. The isolates were able to utilize fenitrothion as a sole source of carbon and energy, producing 3-methyl-4-nitrophenol as the intermediate metabolite during the complete degradation of fenitrothion. Twenty-two of 27 isolates were able to degrade parathion, methyl-parathion, and p-nitrophenol but only strain BS2 could degrade EPN(O-ethyl-O-p-nitrophenyl phenylphosphorothioate) as a sole source of carbon and energy for growth. Eighteen of the 27 isolates had plasmids. When analyzed with PCR amplification and dot-blotting hybridization using various specific primers targeted to the organophosphorus pesticide hydrolase genes of the previously reported isolates, none of the isolates showed positive signals, suggesting that the corresponding genes of our isolates had no significant sequence homology with those of the previously isolated organophosphate pesticide-degrading bacteria.

• Journal of Microbiology
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• 제45권3호
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• pp.219-226
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• 2007

Insertion sequence IS1112 is a repetitive element with a relatively high number of copies in Xanthomonas oryzae pv. oryzae (Xoo), the causal agent of bacterial blight of rice (Oryza sativa L.). Three new loci of IS1112 were identified in seven Chinese strains of Xoo using a single oligonucleotide primer J3; 5'-GCTCA GGTCAGGTGGCCTGG-3' by insertion-sequence-based polymerase chain reaction (IS-PCR). Among the three new loci of IS1112, two were located in the open-reading frame region of genes fhuA and cirA, which encode TonB-dependent receptors, and the third in ISXo2, another type of insertion sequence in Xoo genome. Three variants of IS1112 were identified in those three loci based on their sequence similarities: two were identical to IS1112a and IS1112b, reported in strain PXO86 from the Philippines, while the third was a new member of IS1112, defined as IS1112d. Inserting IS1112 in gene fhuA caused three bases, GGT, to be duplicated at the target site, but inserting it in gene cirA did not cause any duplication in the target site. The diversity of IS1112 sequence and insertion loci in Xoo genome and their potential effects are discussed.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2005년도 추계학술대회 논문집
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• pp.283-288
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• 2005

기존의 기계적인 센서들보다 높은 민감도와 선형성을 가지는 반도체 센서들은 크기가 작고 일괄공정에 의해 제작될 수 있는 반도체 공정 기술로 제작되므로 다양한 산업에서 적용되고 있다. 하지만 열과 반복적인 외부 하중은 센서의 수명에 치명적인 영향을 미치고 있고, 특히 외부에서 가해지는 열은 센서를 구성하는 구조물보다 신호를 전달하는 배선의 피로 수명에 지대한 영향을 미치고 있으므로 이에 대한 영향성을 분석할 수 있는 프로세스를 확립하고, 이후 다양한 재료의 반복적인 열하중에 대한 피로 수명을 평가하여 사용 온도에 대한 적절한 재료를 선정할 수 있는 자료를 제시하고자 하였다.

• 한국재난정보학회 논문집
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• 제8권4호
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• pp.391-400
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• 2012

최근 건설 산업에서 FRP는 재료적 장점들 때문에 구조물의 보강 재료로서 많이 사용되어지고 있다. FRP 외부부착보강은 중량에 비하여 높은 강도 및 강성, 우수한 내구성과 시공성 등 여러 가지 장점을 가지는 공법이다. 그러나 외부부착보강은 구조물이 투수성이 낮은 보강재로 밀폐되고 수분이 외부로 배출되지 못함으로 인하여, 장기적인 구조물의 손상을 발생시키는 문제점이 있다. 본 연구에서는 인발성형으로 제작되었으며, 기존의 FRP와 재료역학적 성질은 동등하면서 투수성을 지녀 구조물의 내구성, 부착성능에 유리한 유리섬유패널(GP)에 대해서 정적실험을 통해 실험체의 반복하중 하에서의 하중-처짐 선도, 파괴형태, 하중-변형율 관계 등을 조사하였다. 실험결과 2,000,000회 피로실험 후에도 파괴에 도달하지 않았으며, 보의 처짐이나 콘크리트 압축변형률이 기준 콘크리트 시험체보다 현저히 낮은 것으로 측정되어 장기 부착력 및 장기 내구성능이 우수함을 알수 있었다.

• 한국포장학회지
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• 제30권1호
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• pp.53-62
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• 2024

Molded pulp products has become more attractive than traditional materials such as expanded polystyrene foam (EPS) owing to low-priced recycled paper, environmental benefits such as biodegradability, and low production cost. In this study, various design factors regarding compression and cushioning characteristics of the molded pulp cushion with truncated pyramid-shaped structural units were analyzed using a test specimen with multiple structural units. The adopted structural factors were the geometric shape, wall thickness, and depth of the structural unit. The relative humidity was set at two levels. We derived the cushion curve model of the target molded pulp cushion using the stress-energy methodology. The coefficient of determination was approximately 0.8, which was lower than that for EPS (0.98). The cushioning performance of the molded pulp cushion was affected more by the structural factors of the structural unit than by the material characteristics. Repeated impacts, higher static stress, and drop height decreased the cushioning performance. Its compression behavior was investigated in four stages: elastic, first buckling, sub-buckling, and densification. It had greater rigidity during initial deformation stages; then, during plastic deformation, the rigidity was greatly reduced. The compression behavior was influenced by structural factors such as the geometric shape and depth of the structural unit and environmental conditions, rather than material properties. The biggest difference in the compression and cushioning characteristics of molded pulp cushion compared to EPS is that it is greatly affected by structural factors, and in addition, strength and resilience are expected to decrease due to humidity and repetitive loads, so future research is needed.

• Geomechanics and Engineering
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• 제37권4호
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• pp.341-358
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• 2024

This paper reports several plane-strain trapdoor tests conducted to investigate the effects of reinforcement on soil arching development under localized surface loading with a loading plate width three times the trapdoor width. An analogical soil composed of aluminum rods with three different diameters was used as the backfill and Kraft paper with two different stiffness values was used as the reinforcement material. Four reinforcement arrangements were investigated: (1) no reinforcement, (2) one low stiffness reinforcement R1, (3) one high stiffness reinforcement R2, and (4) two low stiffness reinforcements R1 with a backfill layer in between. The stiffness of R2 was approximately twice that of R1; therefore, two R1 had approximately the same total stiffness as one R2. Test results indicate that the use of reinforcement minimized soil arching degradation under localized surface loading. Soil arching with reinforcement degraded more at unloading stages as compared to that at loading stages. The use of stiffer reinforcement had the advantages of more effectively minimizing soil arching degradation. As compared to one high stiffness reinforcement layer, two low stiffness reinforcement layers with a backfill layer of certain thickness in between promoted soil arching under localized surface loading. Due to different states of soil arching development with and without reinforcement, an analytical multi-stage soil arching model available in the literature was selected in this study to calculate the average vertical pressures acting on the trapdoor or on the deflected reinforcement section under both the backfill self-weight and localized surface loading.

• 한국균학회지
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• 제47권4호
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• pp.385-392
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• 2019

플라스틱 비닐을 이용한 톱밥배지를 기반으로 하는 표고 재배방식은 환경문제를 일으킬 수 있다. 본 연구에서는 비닐 대신 플라스틱 용기를 이용하여 표고의 재배실험을 실시하였다. 참나무 톱밥과 밀기울을 4:1 비율로 혼합하여 함수율을 65%로 맞춘 톱밥배지를 분리가 가능한 플라스틱 용기에 입병하였다. 접종한 배지는 배양일, 명배양 광조건 등을 달리하여 80일 또는 120일간 배양하였다. NIFoS 2464 균주에서는 300 Lux의 광도에서 명배양을 진행하였을 경우 배지의 중량감소율이 더 높았고, 빛의 세기는 배지의 중량감소와 연관이 있는 것으로 나타났다. 버섯 발생시에는 발생실의 공기순환 팬 속도를 달리하였다. NIFoS 2464 균주는 암배양 80일, 명배양 500 Lux에서 40일, 공기순환 팬 속도 30 rpm에서 가장 높은 생산량을 나타내었다. 120일 동안 배양된 병 배지의 경우, 명배양을 40일간 진행한 배지에서 생산량이 더 높았다. 암배양을 80일간 진행한 배지의 경우 배지 상면으로의 반복적인 살수작업 및 배양실 내의 빛 자극으로 인해 자실체가 발생하였다. 첫 수확 후 배지의 수축으로 인해 배지는 병으로부터 분리되었다. 분리된 플라스틱 병은 버섯 재배에 재사용할 수 있으며 이를 이용하면 플라스틱 폐기물의 양을 줄일 수 있을 것으로 기대된다.