http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
상온에서의 기계적-화학적 전처리가 셀룰로오스 및 용액 특성에 미치는 영향
오세영,서풍,조병욱 한국펄프·종이공학회 2024 펄프.종이기술 Vol.56 No.2
. The high degree of polymerization (DP) of cellulose makes it difficult to dissolve the cellulose fibers and increases the viscosity of the dissolved cellulose solution, which limits the ability to produce small particles of beads by using small needles or nozzles by dropping or spraying methods. This study explores the development of a technology to control the DP of cellulose of a chemical pulp through a mechanochemical pretreatment at room temperature. The chemical pulp was pretreated by three methods (ethanol-hydrochloric acid pretreatment, ball milling pretreatment, or acid-ball milling pretreatment), and the effects on fiber and cellulose properties, cellulose solution properties, and bead size were explored. Our findings reveal that wet ball milling pretreatment with acid is more effective in reducing DP of cellulose than acid treatment or ball milling treatment alone. The DP of cellulose of chemical pulp was reduced from 1400 to 400 after 1 h of acid-ball milling treatment at room temperature. The reduction in the DP of cellulose decreased the viscosity and surface tension of the cellulose solution, which affected the size of cellulose beads. In addition, the acid-ball milling pretreatment resulted shortening of fiber length and external fibrillation, and did not affect the crystal structure of cellulose-I, unlike the ball milling treatment, which destroyed the fiber morphology and the cellulose crystal structure.
오세영 한국해운물류학회 2002 해운물류:이론과실천 Vol.- No.4
택배서비스업은 운송서비스에 대한 소비자 주도형의 사회적 요청에 부응하는 것이고, 언제, 어디서든지 전화 한 통화로서 집하에서 배송ㆍ확인까지 해주는 편리성 및 정확ㆍ신속성에 주안점을 둔 일관서비스를 제공하는 혁신적인 운송체계라고 할 수 있다. 이러한 택배서비스업에 대한 소비자의 욕구는 경제ㆍ사회문화의 발전과 더불어 더욱더 가속화될 것이므로 택배시장의 장래는 매우 밝을 것으로 전망된다. 그러나 대부분의 택배서비스 업체들은 물동량 증가에도 불구하고 거점시설의 부족, 도심지에서의 영업활동 제한, 인력부족, 고객서비스관리의 미흡 등으로 운영의 효율성이 떨어지고 있어 국가적 물류산업의 육성차원에서 적극적인 지원책과 업계의 개선방안에 관하여 고찰하고자 한다. Courier service has been developed in accordance with changes of social needs. It is a revolutionary inter-modal transportation system which has the focus on convenient, correct and quick services and a door-to-door carrying system. Consumers will continually demand the better courier service and their purchasing of the services will be greatly increased in the near future. However, it is known that management performances of most courier service providers in Korea are not good in spite of an increasing number of cargoes. The reasons were shortage of logistics facilities, regulations of business in the city, insufficient supply of manpower, and deficit of customer service. They caused forfeiture of competitivness and increase of logistics cost of courier business, and also caused the couriers not to fill up diversified needs of customers. Therefore, in order to develope continually courier service industry, most of all, an efficient management systems of courier business firms and the policies of promotion of courier industry have to be constructed.