• 한국항만경제학회지
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• 제23권3호
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• pp.103-126
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• 2007

우리나라와 일본정부는 해운정책의 일환으로써 계획조선정책을 실시하였다. 한국의 경우, 선복의 확보, 자국화자국선의 실시, 국내조선산업과 해운을 연계하여 육성하기 위하여 계획조선제도의 도입을 실시하였다. 일본도 마찬가지로 제2차세계대전중에 파괴된 상선대의 회복 및 자국조선산업의 활성화를 위하여 계획조선제도를 실시하였다. 우리나라의 계획조선정책은 선박자본측면에서 해운회사의 부담을 경감시킴으로써 우리나라 해운회사들이 저렴한 선원비와 화물유보정책 등의 지원하에서 급속한 성장을 이룩하는데 일조를 담당하였음은 인정되나 문제점도 발견된다. 첫째, 조달재원의 금리적인 측면에서 선진 해운국의 조달금리와 비교하여 볼 때 열위에 있었다는 점이다. 둘째, 계획조선을 위한 조달재원이 부족하여 수요를 충족시키지 못한 점이다. 셋째, 한국정부는 시장환경변화에 따른 신속한 정책의 반영이 결여되어 있었다. 오늘날 세계해운시장이 개방화, 국제화되고 있는 시점에서 경쟁력 있는 선박의 확보는 해운기업의 중요한 경영요소의 하나이며 우리나라도 이를 지원할 수 있는 방향으로 해운정책이 수립되어야 한다.

• 대한인간공학회지
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• 제29권2호
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• pp.225-239
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• 2010

A high prevalence of farmer's work-related musculo-skeletal disorders (MSDs) have been reported in precedent studies. Risk factors - physical, chemical, biological, ergonomic risk factor etc. - in farm-work were identified by previous studies. To prevent farmers from exposing to them and reduce, Agricultural Safety Technology were introduced and used on farm. The purpose of this study is to review and summarize the agricultural safety technology on farm in Korea. According to strategy principles, this technology is classified as four criteria - workload reduction by reducing awkward posture, workload reduction by using manual material handling aids, Comfort improvement by protecting worker from hot, cold environment and work efficiency improvement by workplace redesign and cultivation modification. This technology includes transporting tools, working cloth, personal protective equipment, and pesticide-proof Clothing. Anthropometric study of Korean farmers was also carried out to support the development of equipment and clothes. In long terms, it needs to precaution activity from risk factors by using cultivation modification and working improvement. Although working condition gets better and workload reduce by this technology, it required customized safety technology in each crops - rice cultivation, horticulture and livestock farming. And farmers should use the assistive technology and participate voluntarily in ergonomic intervention program.

• Design & Manufacturing
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• 제14권1호
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• pp.42-48
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• 2020

Titanium alloy has been in the spotlight as a core material in high-tech industries that require high strength and light weight because it has excellent strength and corrosion resistance and strength is higher than that of steel. Therefore, in various industries, existing steel products are intended to be replaced with titanium alloys. Titanium alloys can cause cutting tool breakage during cutting, and heat generated during cutting does not dissipate, accumulates in tools and workpieces, resulting in large wear and tear on thin workpieces. In addition, since titanium alloy is a metal with high chemical activity, the wear of the tool becomes more severe when the cutting speed is high, so machining of titanium bolt through cutting is very disadvantageous in terms of productivity. Therefore, the production of bolts using titanium alloys is being produced through a forging process to improve productivity and product quality. In this paper, hot forging molding analysis was performed on bolts used for fastening automobile parts using Ti-6Al-4V alloy, which is the most commonly used titanium alloy.

• 대한기계학회논문집A
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• 제39권6호
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• pp.639-644
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• 2015

원형 리튬 전지는 노트북, 파워툴이나 전기 자동차와 같이 고용량/고율 방전이 필요한 분야에서 널리 사용되는 이차전지 중의 하나로 저장된 화학 에너지를 전기화학적 반응을 통해 전기 에너지로 변환하는 장치이다. 센터 핀은 원형 리튬 전지 내에 가스 분출 채널 확보를 위해 젤리-롤 중심홀이 충/방전 중 좁혀지는 것을 방지하고, 낙하 충격 시 완충 작용으로 분리막 손상을 방지하여 내부 단락을 막아주는 역할을 담당하는 부품이다. 본 연구에서는 센터 핀의 중요한 역할들에 대해 실험적으로 검증하기 위해서 센터 핀 유/무에 따른 2 가지 실험을 진행하였다. 하나는 연속 50 회 충/방전 싸이클 후의 젤리-롤 중심홀의 변화이고, 다른 하나는 UL 표준 기준에 의한 자유 낙하 충격 실험을 통한 젤리-롤 내 분리막 손상에 의한 내부 단락 여부이다. 이러한 실험적 결과를 바탕으로 원형 전지의 센터핀이 안전성 측면에서 반드시 필요한 부품임을 확인할 수 있었다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2010년도 춘계학술발표대회
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• pp.37.2-37.2
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• 2010

Recently $Li_{1.2}Ni_{0.2}Mn_{0.6}O_2$ has been consistently examined and investigated by scientists because of its high lithium storage capacity, which exceeds beyond the conventional theoretical capacity based on conventional chemical concepts. Consequently, $Li_{1.2}Ni_{0.2}Mn_{0.6}O_2$ is considered as one of the most promising cathode candidates for next generation in Li rechargeable batteries. Yet the mechanism and the origin of the overcapacity have not been clarified. Previously, many authors have demonstrated simultaneous oxygen evolution during the first delithiation. However, it may only explain the high capacity of the first charge process, and not of the subsequent cycles. In this work, we report a clarified interpretation of the structural evolution of $Li_{1.2}Ni_{0.2}Mn_{0.6}O_2$, which is the key element in understanding its anomalously high capacity. We identify how the structural evolution of $Li_{1.2}Ni_{0.2}Mn_{0.6}O_2$ occurs upon the electrochemical cycling through careful study of electrochemical profiles, ex-situ X-ray diffraction (XRD), HR-TEM, Raman spectroscopy, and first principles calculation. Moreover, we successfully separated the structural change at subsequent cycles (mainly cation rearrangement) from the first charge process (mainly oxygen evolution with Li extraction) by intentionally synthesizing sample with large particle size. Consequently, the intermediate states of structural evolution could be well resolved. All observations made through various tools lead to the result that spinel-like cation arrangement and lithium environment are created and embedded in layered framework during repeated electrochemical cycling.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2006년도 정기학술발표대회 논문집
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• pp.213-220
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• 2006

플랜트건설 산업은 엔지니어링과 기계설비의 조달, 시공이 융합된 복합산업(EPC)으로 건설업체의 수주에 따라 기계 ${\cdot}$ 설비 등 타 분야의 성장을 함께 도모할 수 있는 높은 고부가가치 산업이다. 따라서 플랜트건설 수주의 증대는 향후 건설업체뿐만 아니라 국가경제 전반의 성장에 지대한 영향을 끼치는 중요한 이슈이다. 특히, 근래에 중동지역의 경우 고유가에 자극 받은 국가들의 가스와 석유화학 등의 시설에 대한 지속적인 투자로 플랜트 분야의 수요가 급증하는 등 해외 건설시장에서의 플랜트 분야의 시장이 매우 성장하고 있다. 하지만 국내의 해외플랜트 건설업체들이 미국, 유럽 및 일본의 선진기업들과의 경쟁에서 우의를 점하여, 매출과 이윤을 늘리고 꾸준히 사업을 영위하기 위해서는 플랜트 건설산업의 국제 경쟁력을 조속히 확보하는 것이 필요하다. 따라서 본 연구는 해외 건설시장에서 국내 플랜트 관련 업체들의 프로젝트 수행기술 전반을 향상시켜 지속적인 경쟁력을 확보하기 위하여 플랜트 건설사업의 각종 표준과 프로젝트 관리 및 정보관리체계 등 플랜트 프로젝트 관리의 선진화된 기술을 개발하고자 한다.

• 환경영향평가
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• 제20권5호
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• pp.705-716
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• 2011

For the efficient discovery of knowledge and information from the observed systems, data mining techniques can be an useful tool for the prediction of water quality at intake station in rivers. Deterioration of water quality can be caused at intake station in dry season due to insufficient flow. This demands additional outflow from dam since some extent of deterioration can be attenuated by dam reservoir operation to control outflow considering predicted water quality. A seasonal occurrence of high ammonia nitrogen ($NH_3$-N) concentrations has hampered chemical treatment processes of a water plant in Geum river. Monthly flow allocation from upstream dam is important for downstream $NH_3$-N control. In this study, prediction models of water quality based on multiple regression (MR), artificial neural network and data mining methods were developed to understand water quality variation and to support dam operations through providing predicted $NH_3$-N concentrations at intake station. The models were calibrated with eight years of monthly data and verified with another two years of independent data. In those models, the $NH_3$-N concentration for next time step is dependent on dam outflow, river water quality such as alkalinity, temperature, and $NH_3$-N of previous time step. The model performances are compared and evaluated by error analysis and statistical characteristics like correlation and determination coefficients between the observed and the predicted water quality. It is expected that these data mining techniques can present more efficient data-driven tools in modelling stage and it is found that those models can be applied well to predict water quality in stream river systems.

• 펄프종이기술
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• 제45권2호
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• pp.46-55
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• 2013

Recently, there are growing interests on carbon emissions related in climate change which is worldwide emerging important issue. Some research works are now carrying out in order to reduce the carbon emission in pulp and paper industries by the synthesis of precipitated calcium carbonate using the exhaust carbon dioxide from combustion furnace or incinerator. However, for solving the original problems on carbon emission, we need to consider the analysis of basic methodology on $CO_2$ through the process efficiencies. There are two general tools for carbon emissions; one is the greenhouse gas inventory and the other is $LCCO_2$ method which is applied to particular items of raw materials and utilities in unit process. In this study, the carbon emissions in wood-containing printing paper production line were calculated by using $LCCO_2$ method. The general materials and utilities for paper production, such as fibrous materials, chemical additives, electric power, steam, and industrial water were analyzed. As the results, $Na_2SiO_3$ showed the highest loads in carbon emissions, and the total amount of carbon emissions was the highest in electricity. In the production line of printing paper using de-inked pulp and BTMP, as the mixing ratio of DIP was higher, the carbon emissions were decreased because of high use of electric power in TMP process.

• 공업화학
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• 제3권4호
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• pp.579-587
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• 1992

올레핀의 오존화 반응에서 보여지는 통상의 반응경로가 pyridine의 도움으로 modification될 수 있는지 여부가 검토되었다. 먼저, trans-3-hexene의 오존 산화 반응이 aprotic non-participating solvent인 n-pentane과 dichloromethane을 사용하여 시험되었다. 덧붙여, 올레핀의 오존 산화 반응에서 pyridine의 역할과 반응기구를 검토하기 위하여, monomeric과 Polymeric ozonides의 염기성 촉매 분해반응이 시험되었다. 본 연구에서 반응 과정의 고찰뿐만 아니라 생성물의 정량, 정성 분석을 위하여 현대적인 분석 기기들이 사용되었다. 본 연구의 결과로서, Pyridine 무존재하 aprotic solvent에서 올레핀과 오존의 반응으로 주로 과산화물인 monomeric이나 polymeric ozonides가 생성되었으며, pyridine 존재하에서는 과산화물의 생성없이 propionaldehyde와 Criegee zwitterion의 자리옮김 생성물인 propionic acid가 주생성물이었다. 또한, tans-3-hexene의 오존 산화 반응에서 Pyridine의 촉매작용에 의하여 trans-3-hexene의 Criegee zwitterion의 propionic acid로 이성화되는 것으로 사료된다.

• 생약학회지
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• 제40권2호
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• pp.109-117
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• 2009

We examined the purity of six heparin samples by using heparinase, chondroitinase, $^{1}H-NMR$, and polyacrylamide gel electrophoresis. To obtain high molecular weight contaminants from heparin samples, heparinase I - digested samples were subjected to the exhaustive microcon filtration. The filtration process removed heparin-derived di- and oligosaccharides effectively. By combining chondroitinase ABC treatment and strong anion exchange - high performance liquid chromatography, the result showed all six samples contained chondroitin sulfate as a contaminant ranging from 1.3 to 14.9%. Among them, sample S3 showed the highest content of 14.9%, which was further analyzed by chondroitinase AC treatment to confirm chondroitin sulfate B (dermatan sulfate). $^{1}H-NMR$ chemical shifts of N-acetyl groups clearly suggested the existence of chondroitin sulfate B (sample S3) and oversulfated chondroitin sulfate (samples S2 and S4) as contaminants. In addition, polyacrylamide gel electrophoresis was useful for qualitative detection on the sample's purity. These results suggest that the tools of heparinase I and chondroitinase ABC in combination with NMR spectroscopy would give very useful information for investigation of heparin contaminants such as oversulfated chondroitin sulfate and dermatan sulfate in heparin samples.