• 제목/요약/키워드: critical means

검색결과 975건 처리시간 0.046초

RPF의 열적 안정성과 한계발화온도 (Thermal Stability and Critical Ignition Temperature of RPF)

  • 임우섭;최재욱
    • 한국화재소방학회논문지
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    • 제22권1호
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    • pp.99-104
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    • 2008
  • 재생연료 중에서 고체물질에 해당하는 RPF(Refuse Paper & Plastic Fuel)는 친환경적인 요소와 한정된 지하자원에 대한 대체에너지로서 세계적으로 그 사용량이 증가하는 추세에 있으며, 제조 또는 저장과정에서 종종 화재가 발생하기도 한다. 따라서 RPF에 대한 열적안정성과 임계발화온도에 대한 연구가 필요하며, 이러한 연구를 수행하기 위하여 봄베 열량계, TG-DTA, MS80, SIT-II, Wire Basket를 이용하여 실험을 하였다. 그 결과 RPF는 26.4-28.3 MJ/kg의 발열량을 지니고 있었으며, TG-DTA로 초기 열분해 온도를 측정한 결과 승온속도 2 K/min에서 $192^{\circ}C$로 나타났으며, 미소열량 측정 장치인 MS80으로 분석한 결과 수분이 함유되지 않은 순수한 RPF가 수분이 20%함유된 RPF보다 발열량이 더 큰 것으로 나타났다. 또한 단열자연발화 실험장치인 SIT-II가 Wire Basket Test 보다 낮은 온도인 $118.5^{\circ}C$까지 발화하였으며, Frank-Kamenetskii의 식으로부터 계산되어진 한계발화온도는 무한평판을 기준으로 약 10 m 높이로 저장되어 있을 때, $80^{\circ}C$에서도 발화가 가능한 것으로 나타났다.

노인이 경험한 대체요법의 양상에 관한 연구 1 (A Study on the Patterns of Alternative Therapy Experienced by the Aged)

  • 이강이;김순이
    • 대한간호학회지
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    • 제29권2호
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    • pp.336-345
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    • 1999
  • This study looks at the various alternative therapy methods used in day to day life by elderly, over 60 years of age. The elderly have come to know and practice these methods for the following reasons it is good for the health ; it is the method used in the of fen days when there wesn't modern medicine ; it has been passed down from generations ; it can be done at home without having the need to go to the hospital ; acupuncture or poulticing can be used ; it can be done at home, which was an important factor in rural areas where hospitals are few and far between ; and 〔herbal〕 medicine could be prepared at home at no cost ; it derives from experience ; it is impossible to ignore tradition passed down through the generations. Diet control and plants (herbs) are methods most often used. as they are easy to find and can be readily used in critical situations. Other methods include oriental medicine practices of moxibustion with moxa cone, negative therapy, hand and finger acupunture, finger press method. ordinary acupunture, manual healing methods of massage. diaphoretic therapy and meditation to reach a state of calm, and qigong dirigation. The reasons for its use are as follows ; it has been used before ; it is effective ; there is some improvement after the treatment ; it is not harmful to the body ; medicine cannot be obtained and it is the only thing available ; it is not good for an old person to go to the hospital everyday. the symptoms are not serious enough to go to a hospital : and acupuncture is for these things. The means that the elderly have come to practice these methods are : it has been used since the past ; it has been told by the elders ; they have been told by friends ; it was part of their knowledge ; and they have come to know by watching their mother. Further, to regain vitality lost through old age, the elderly have relied on hot soup. a hearty meal. brewed honey water, pumpkin, or ginseng. Humans, by instinct. would rub or massage the areas that caused pain. These actions, combined with a breathing technique have been recognized in Tong-Eui-Bo-Gam(the essential of eastern medicine), the complete work of early modern medicine, are a useful means to revive chi(기). This knowledge is thought to have greatly affected our heathy lifestyle. Furthermore, though the demand for medical services would increase with age, the elderly have not always been able to tend to their needs at the hospital for reasons economic or other. Hence, these alternative therapy methods seem to have been practiced as a temporary means of relief. The excellence of our traditional therapeutic custom has not received full recognition due to the argument relating to its scientific merits. As a result, it has become vital to prove their effectiveness through scientific and other experimental means. The potency of moxibustion with moxa cone and hand and finger acupunture have been proven scientifically. but diet and herbal methods appear to be practiced as a result of customs passed down from generations. In addition, it is submitted that the effectiveness of the traditional methods of disease control and our heathy lifestyle that are easily found in the nursing field must be verified.

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텍스트성을 활용한 다문화 멘토링 활동에서의 수업비평 탐색 (Exploring class criticism in multicultural mentoring activities using textuality)

  • 오세경;황해영
    • 예술인문사회 융합 멀티미디어 논문지
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    • 제8권9호
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    • pp.563-571
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    • 2018
  • 본 연구의 목적은 대학생인 멘토들의 전문성 신장과 비평적인 성찰을 유도하기 위해 다문화 멘토링 수업활동에 대한 방향을 모색하는 데 그 목적이 있다. 이를 위해 멘토-멘티의 다문화 멘토링에서 이루어지는 전반적인 활동 내용 및 현상을 활동 텍스트로 보고, 일곱 가지의 텍스트성을 적용하여 다문화 멘토링 수업활동에 대한 방향을 탐색하였다. 그 결과, 응결성은 멘토와 멘티가 다문화 멘토링 수업활동을 지속적으로 하기 위한 관계적인 측면을 뜻하고, 응집성은 수업활동 과정에서 파생되는 의미들이 결속되어 멘토와 멘티 모두에게 수업활동에 대한 하나의 주제나 정체성을 이루어 내는 것을 말한다. 의도성은 멘토가 멘토링 수업활동 전에 수업에 대한 의도나 목표를 갖는 것을 의미하고, 용인성은 다문화 멘토링 수업활동 과정에서 멘토가 생산한 텍스트를 멘티에 의해 받아들여질 때 수업활동 텍스트로서 의미를 가지는 것을 말한다. 정보성의 경우 수업활동 과정에서 멘토가 생산한 텍스트를 멘티가 예측가능할 때에는 정보성이 낮으며, 예측가능 정도가 낮을 경우에는 정보적인 가치가 높다는 관점이다. 상황성은 수업활동 과정에서 물리적인 텍스트 상황과 멘티의 상황에 따라 수업활동에 대한 상황성은 달라질 수 있고, 상호텍스트성은 다문화 멘토링 수업활동의 경우 멘토가 수업활동 텍스트를 새롭게 창조하여 생산하는 경우를 제외하고는 멘토의 학습경험, 동료 친구의 자문, 교육 등을 통해 수업활동 텍스트를 생산하는 것과 관련된다.

백서 두개골 결손부에서 키토산의 골조직 재생 유도 효과 (The Bone Regenerative Effects of Chitosan on the Calvarial Critical Size Defectin Sprague Dawley Rats)

  • 정의원;서종진;최성호;조규성;채중규;김종관
    • Journal of Periodontal and Implant Science
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    • 제30권4호
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    • pp.851-870
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    • 2000
  • The major goals of periodontal therapy is the functional regeneration of periodontal supporting structures already destructed by periodontal disease as well as the reduction of signs and symptoms of progressive periodontal disease. There have been many efforts to develop materials and therapeutic methods to promote periodontal wound healing. There have been increasing interest on the chitosan made by chitin. Chitin is second only to cellulose as the most abundant natural biopolymer. It is a structural component of the exoskeleton of invertebrates(e.g., shrimp, crabs, lobsters), of the cell wall of fungi, and of the cuticle of insects. Chitosan is a derivative of chitin made by deacetylation of side chains. Many experiments using chitosan in various animal models have proven its beneficial effects. The aim of this study is to evaluate the osteogenesis of chitosan on the calvarial critical size defect in Sprague Dawley rats. An 8 mm surgical defect was produced with a trephine bur in the area of the midsagittal suture. The rats were divided into two groups: Untreated control group versus experimental group with 50mg of soluble chitosan gel. The animals were sacrificed at 2, 4 and 8 weeks after surgical procedure. The specimens were examined by histologic, histomorphometric and radiodensitometric analyses. The results are as follows: 1. The length of newly formed bone in the defects was $102.91{\pm}25.46{\mu}m$, $219.46{\pm}97.81{\mu}m$ at the 2 weeks, $130.95{\pm}39.24{\mu}m$, $212.39{\pm}89.22{\mu}m$ at the 4 weeks, $181.53{\pm}76.35{\mu}m$ and $257.12{\pm}51.22{\mu}m$ at the 8 weeks in the control group and experimental group respectively. At all periods, the means of experimental group was greater than those of control group. But, there was no statistically significant difference between the two groups. 2. The area of newly formed bone in the defects was $2962.06{\pm}1284.48{\mu}m^2$, $5194.88{\pm}1247.88{\mu}m^2$ at the 2 weeks, $5103.25{\pm}1375.88{\mu}m^2$, $7751.43{\pm}2228.20{\mu}m^2$ at the 4 weeks and $8046.20{\pm}818.99{\mu}m^2$, $15578.57{\pm}5606.55{\mu}m^2$ at the 8 weeks in the control group and experimental group respectively. At all periods, the means of experimental group was greater than those of control group. The experimental group showed statistically significant difference to the control group at the 2 and 8 weeks. 3. The density of newly formed bone in the defects was $14.26{\pm}6.33%$, $27.91{\pm}6.65%$ at the 2 weeks, $20.06{\pm}9.07%$, $27.86{\pm}8.20%$ at the 4 weeks and $22.99{\pm}3.76%$, $32.17{\pm}6.38%$ at the 8 weeks in the control group and experimental group respectively. At all periods, the means of experimental group was greater than those of control group. The experimental group showed statistically significant difference to the control group at the 2 and 8 weeks. These results suggest that the use of chitosan on the calvarial defects in rats has significant effect on the regeneration of bone tissue in itself

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n-부탄올 수용액에서 TTAB/Brij 35 혼합계면활성제의 미셀화에 대한 연구 (Study on the Micellization of TTAB/Brij 35 Mixed Systems in Aqueous Solutions of n-Butanol)

  • 길한내;이병환
    • 공업화학
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    • 제18권3호
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    • pp.267-272
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    • 2007
  • $25^{\circ}C$의 순수 물 및 n-부탄올 수용액(0.1 M, 0.2 M 및 0.3 M)에서 양이온 계면활성제인 trimethyltetradecylammonium bromide (TTAB)와 비이온 계면활성제인 polyoxyethylene (23) lauryl ether (Brij 35)의 혼합계면활성제의 임계미셀농도 (CMC)와 반대이온의 결합상수값(B)을 TTAB의 겉보기 몰분율(${\alpha}_1$)의 함수로서 전도도법과 표면장력계법으로 측정하였다. 이와 같이 측정한 CMC 값에 비이상적 혼합미셀화 모델을 적용함으로써 여러 가지 열역학적 함수값($X_i$, ${\gamma}_i$, $C_i$, ${a_i}^M$, ${\beta}$${\Delta}H_{mix}$)들을 계산하고 분석하였다. 또한 TTAB/Brij 35 혼합계면활성제의 미셀화에 미치는 n-부탄올의 농도에 따른 열역학 함수값들의 변화를 측정하고 분석하였다.

순수 물에서 SDS/Brij 30, DBS/Brij 30 및 SDS/DBS 혼합계면활성제의 미셀화에 대한 비교연구 (Comparative Study on the Micellization of SDS/Brij 30, DBS/Brij 30, and SDS/DBS Mixed Surfactant Systems in Pure Water)

  • 이병환;박인정
    • 대한화학회지
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    • 제55권3호
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    • pp.379-384
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    • 2011
  • [ $25^{\circ}C$ ] 순수 물에서 음이온성 계면활성제인 DBS(sodium dodecyl benzenesulfonate)와 SDS(sodium dodecylsulfate) 그리고 비이온성 계면활성제인 Brij 30(polyoxyethylene(4) lauryl ether) 사이의 혼합미셀화에 대한 임계미셀농도(CMC)와 반대이온의 결합상수값(B)을 전도도법과 표면장력계법으로 측정하였다. 이와 같이 측정한 CMC값에 비이상적 혼합미셀화 모델을 적용함으로써 여러 가지 열역학적 함수값($X_i,\;{\gamma}i,\;C_i,\;a_i^M,\;{\beta}$${\Delta}H_{mix}$)들을 계산하여 상호 비교분석하였다. 그 결과, SDS는 DBS보다 Brij 30과 더욱 강한 상호작용을 이루었으며, SDS/Brij 30 혼합계면활성제가 이상적 혼합미셀화로부터 가장 큰 음의 벗어남을 보였다. 그리고 SDS/DBS 혼합계면활성제는 거의 이상적 혼합미셀화를 이루는 것으로 나타났다.

DBS/Brij 35 혼합계면활성제의 미셀화에 미치는 n-부탄올 효과 (Effect of n-Butanol on the Micellization of DBS/Brij 35 Mixed Surfactant Systems)

  • 이병환;박인정
    • 대한화학회지
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    • 제50권5호
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    • pp.355-361
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    • 2006
  • 순수 물 및 n-부탄올 수용액(0.1M, 0.2M, 0.3M)에서 음이온 계면활성제인 sodium dodecyl benzenesulfonate(DBS)와 비이온 계면활성제인 dodecyl polyoxyethylene(23) lauryl ether(Brij 35)의 혼합계면활성제의 임계미셀농도(CMC)와 반대이온의 결합상수값(B)을 DBS의 겉보기 몰분율(1)의 함수로서 전도도법과 표면장력계법으로 측정하였다. 이와 같이 측정한 CMC값에 비이상적 혼합미셀화모델을 적용함으로써 여러 가지 열역학적 함수값(Xi, i, Ci, aiM, 및 Hmix)들을 계산하고 분석하였다. 그리고 DBS/Brij 35 혼합계면활성제의 미셀화에 미치는 n-부탄올의 농도에 따른 열역학 함수값들의 변화를 측정하고 분석하였다.

RFID기반수산물이력제의 성공요인에 대한 탐색적 연구 -소비자 및 공급자 관점을 중심으로- (Critical Success Factors of REID-based Fisheries Traceability Systems: From the Perspectives of Consumers and Suppliers)

  • 김진백
    • 수산경영론집
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    • 제38권2호
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    • pp.25-40
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    • 2007
  • Recently, fisheries safety has been a matter of primary concern among consumers and suppliers. This phenomenon made them require the introduction of fisheries traceability systems. For traceability systems to be effective, automatic identification means play an important role. Therefore, RFID-based fisheries traceability systems are more required than barcode-based fisheries traceability systems. Unlikely EU and Japan, Korea did not accept mandatory traceability regulations. But Many countries began to accept mandatory traceability regulations to diminish food risks. So Korea is expected to adopt them in the near future. The purpose of this study is to find what benefits are generated from the adoption of RFID-based fisheries traceability systems and are related to their success. To do these, this study investigated primary benefits of RFID-based fisheries traceability systems from the perspectives of consumers and suppliers. Consumers' benefits were derived from the perceived risk dimensions. And suppliers' benefits were derived from operational benefits of RFID systems. To purify the benefits from RFID-based fisheries traceability systems, reliability and factor analysis were used. And the refined benefits of RFID-based fisheries traceability systems were additionally analyzed to find which benefits were significantly related to fisheries traceability systems' success. According to the analysis results, all risk dimensions except social risk were significantly related to their success. But in the benefits of suppliers, only "recalls and counterfeits" factor was significantly related to their success. These results implied that fisheries traceability systems should be based RFID technology instead of barcode and fisheries traceability systems were related to almost food risk dimensions. It's because these significant factors are related all food risks except social risk and the benefits of suppliers can be derived from only RFID technology.

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유가공장의 HACCP 적용 (The Application of Hazard Analysis Critical Control Point (HACCP) in Milk Processing Plants)

  • 정동관
    • Journal of Dairy Science and Biotechnology
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    • 제14권1호
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    • pp.1-15
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    • 1996
  • With the starting of Uruguay Round(UR) and World Trade Organization(WTO), the direction of trade in world market has been setting up with the beginning of an opening age. However, world nations has been expressed a deep concern on the marketing and the circulations of unsafe foods, especially in the international trade of food products. Therefore, administration of most countries are taking a firm step on the safety of imported food products. The implementation of hazard analysis critical control point(HACCP) system in food industry is strongly appeared on the world stage at this point. Major international organizations, such as WHO, WTO, and EC have been recognized the importance of HACCP and already documented on their future plan for standardization of food safety in the international trade of food products by means of the this system. Several advanced countries have already developed HACCP system for the food industry and have been producing food products under this system. Now they have proposed rulemakings on a mandatory HACCP program in the production of domestic and imported food products. However, with the lacking of knowledge and information on the HACCP, there has been no actions for applying this system in the food industry of Korea. It is a very clear fact that Korean dairy and food industry will be faced on serious problems in exporting food products without applying HACCP system in the very near future. The objective of this article is to introduce the world trend. necessity, and application of HACCP system in food and dairy industry. Also a HACCP system developed by one dairy processing plant in Europe will be demonstrated as a moldel system.

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Photonic 재로로서 페닐실리카 코팅막의 특성 (Phenyl modified silica sol-gel films for photonics)

  • Ahn, Bok-Yeop;Seok, Sang-Il;Kim, Joo-Hyeun;Lim, Mi-Ae
    • 한국재료학회:학술대회논문집
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    • 한국재료학회 2003년도 추계학술발표강연 및 논문개요집
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    • pp.131-131
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    • 2003
  • The advent of photonic technologies in the field of communications and data transmission has been heavily increasing the demand in integrated optical (IO) circuits capable of accomplishing not only simple tasks like signal, but also more sophisticated functions like all-optical signal routing or active multiplexing/demultiplexing. In the last decade, sol-gel technology has been widely used to prepare optical materials. Sol-gel processes show many promises for the development of low-loss, high-performance glass integrated optical circuits. However, crack formation is likely to occur during heat treatment in thick gel films. In order to overcome the critical thickness limitation, the organic-modified silicate has been widely used. In this case coating matrices have been prepared from the organo-silanes of T structures, acidic catalyst and the as-prepared gel films have been heat-treated below 200$^{\circ}C$ to avoid the crack formation and the degradation of organic components. However, the films prepared in the acidic condition and the low heat temperature make the films contain high OH groups which is the major optical loss function. In this work, C$\sub$6/H$\sub$5/SiO$\sub$1.5/ films were prepared on silicon substrate by sol-gel method using base catalyst in a PTMS/NH$_4$OH/H$_2$O/C$_2$H$\sub$5/OH system. The sol showed spinable viscosity at 50 wt% of solid content, and neglectable viscosity change with time. The films were crack-free and transparent after curing at 450 $^{\circ}C$, and highly condensed to minimize OH content in C$\sub$6/H$\sub$5/SiO$\sub$1.5/ networks. The effects of heat treatment of the films are characterized on the critical thickness, the chemical composition and the refractive indices by means of SEM, FT-IR, TGA, prism coupler, respectively.

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