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The use of gas as fuel, particularly liquefied natural gas (LNG), has increased in recent years owing to its lower sulfur and particulate emissions compared to fuel oil or marine diesel oil. LNG is a low temperature, volatile fuel with very low flash point. The major challenges of using LNG are related to fuel bunkering, storing, and handling during ship operation. The main components of an LNG fuel system are the bunkering equipment, fuel tanks, vaporizers/heaters, pressure build-up units (PBUs), and gas controlling units. Low-pressure dual-fuel (DF) engines are predominant in small LNG-powered vessels and have been operating in many small- and medium-sized ferries or LNG-fueled generators.(Tamura, K., 2010; Esoy, V., 2011[1][2]) Small ships sailing at coast or offshore rarely have continuous operation at constant engine load in contrast to large ships sailing in the ocean. This is because ship operators need to change the engine load frequently due to various obstacles and narrow channels. Therefore, controlling the overall system performance of a gas supply system during transient operations and decision of bunkering time under a very poor infrastructure condition is crucial. In this study, we analyzed the fuel consumption, the system stability, and the dynamic characteristics in supplying fuel gas for operating conditions with frequent engine load changes using a commercial analysis program. For the model ship, we selected the ‘Econuri’, Asia’s first LNG-powered vessel, which is now in operation at Incheon Port of South Korea.

The purpose of this study is to offer the raw data for improving the method of landscape planting in apartment complex by objective surveying and analysing the growth ratio by type and ground planted in landscape tree. The results are as follows. In the survival ratio of tree, Pinus densiflora was the highest and Abies koreana was the lowest in evergreen tree. In case of deciduous tree, the species of the highest survival ratio were Diospyros kaki, Zelkova serrata, Prunus mume, Lagerstroemia indica and Ginkgo biloba. There showed that Sorbus commixta and Chaenomeles sinensis had the lowest survial ratio. In case of tree growth by types, Pinus strobus was the highest and Pinus densiflora var. globosa was the lowest among evergreen trees. Among deciduous trees, the growth ratio of Zelkova serrata was the highest, and the trees showed the lowest growth were Lagerstroemia indica, Magnolia denudata and Cornus officinalis. Pinus strobus, Cornus kousa, Ginkgo biloba, Chionanthus retusa and Acer palmatum were good growth in natural ground, and Zelkova serrata and Prunus armeniaca var. ansu were good in artificial ground. In the future, if you study the growth characteristics and shrubs that are excluded from the study of landscape trees in various locations are expected to derive objective data.

―In this article, silk fabric was treated with silver nitrate (A gNO 3 ) as oxidizing agent, with conditions such as concentration, and treating time, and subsequently treated with reducing agents such as sodium boron hydride (NaBH 4 ) and sodium sulfide (Na 2 S) to obtain cathodic coloration. After coloration of silk fabr ic, dyeing properties (K/S value), colorfastnesses such as wash, rubbing and light, and antibacterial activity property we re examined. AgNO 3 treating time and reducing time did not influence K/S value, whereas the pH value at alkaline region showed a hig h K/S value of silk fabric. The cathodic colorations of silk fa bric with both of reducing agents at 30 ℃ have excellent color fastnesses. Also the high antibacterial ac tivities were obtained by the treatment with silver nitrate even at 1% of lower concentration . Keywords: silver nitrate, redox-reaction, dyeing property, colorfastness, antibacterial〈연구논문(학술)〉 질산은 처리된 실크의 환원 발색 정문화․이문철 1† 한국실크연구원 , 1 부산대학교 유기소재시스템공학과