• Title/Summary/Keyword: 최종속도

Search Result 1,216, Processing Time 0.025 seconds

Comparison of Cleaning Performance of CFC 113 and the Alternatives (CFC 113과 대체세정제의 세정성능 비교)

  • Row, Kyung Ho;Choi, Dai-Ki;Lee, Youn Yong
    • Analytical Science and Technology
    • /
    • v.6 no.5
    • /
    • pp.521-530
    • /
    • 1993
  • According to the Montreal Protocol, CFC 113, one of the ozone-depleting substances, will be prohibited to use as a cleaning solvent essentially in the electronic industry. Therefore, the development of the alternative cleaning solvents to CFC 113 is being accelerated. A number of the alternative cleaning solvents are avialable on the market. The alternatives of Axarel 32(DuPont), Cleanthru 750H(KAO Chemical), and EC-Ultra(Petroferm) are chosen for the comparison of cleaning performance with CFC 113. The test methods for measuring the cleaning performance were composed of the measurement of the physical properties, the experiments on the material compatibility with cleaning solvents, the measurement of the evaporation rate, and finally the experiments of the removal efficiency. Normally the basic physical properties of the alternatives had higher boiling points, viscosity and surface tension, which were quite different to those of CFC 113. In terms of solubility of rosin-based flux, the solubilities of abietic acid (nonpolar organic) were similar, but those of the activator (polar organic) in the alternatives were better than CFC 113. The evaporation of the alternatives was very slow, compared to CFC 113, which had much lower boiling point. All the cleaning solvents showed the good material compatibility with FR4 and Cu-coated PCB. The better removal efficiencies of abietic acid were obtained when using the ultrasonic mechanical energy over the dipping method. The experiments also indicated the very slow-eavaporating solvent was not desirable with the dipping cleaning method, and the differences in the removal efficiency of the alternatives with the ultrasonic cleaning method were negligible. Among the alternatives, the overall cleaning performances were obsorved as almost similar. Before selecting the ultimate cleaning solvent, the application of cleaning machine, environmental issues, and economics are simultaneously considered with the cleaning performance.

  • PDF

Effect on Digestion Efficiency by Adding Microbial Agent in Mesophilic Two-stage Anaerobic Digester (중온2단혐기성소화조에 미생물제재 주입시 소화효율에 미치는 영향)

  • Jung, Byung-Gil;Kim, Seok-Soon;Kang, Dong-Hyo;Sung, Nak-Chang;Choi, Seung-Ho;Lee, Hee-Pom
    • Journal of the Korea Organic Resources Recycling Association
    • /
    • v.11 no.3
    • /
    • pp.75-86
    • /
    • 2003
  • In the near future, the capacity of conventional anaerobic digester is thought to be insufficient because of the increase of the total solids from expansion of intercepting sewer, sewage quantity and direct input of night soil from near apartment districts. The objectives of this study was to investigate the improvement of digestion efficiency using microbial agent(Bio-dh). The system was a pilot-scale, two-staged, anaerobic sludge digestion system. The first-stage digester was heated and mixed. The agitation velocity of the first-stage digester was 120rpm. The second-stage digester was neither heated nor mixed. The Digestion temperature was kept at $35{\pm}1^{\circ}C$ The detention time of digester was 19 days. The dosage of sewage sludge and microbial agent were $0.65m^3/day$ and $0.5{\ell}/day$, respectively. The experiments was run for 25days. Three times a week, $COD_{Mn}$ and SS of effluent, TS, VS, and biogas production rate were measured. Temperature, pH, and alkalinity were measured daily. The results were as follows ; Without microbial agent, digestion efficiencies ranged 46.0%~50.9%(mean=48.6%), with microbial agent(Bio-dh), digestion efficiencies ranged 52.8%~57.3%(mean=54.2%). Consequently, microbial agent(Bio-dh) increased the sludge digestion efficiency about 12%. Also, Without microbial agent, the mean concentration of $COD_{Mn}$ and SS of second-stage digester effluent were 1,639mg/L, 4,888mg/L respectively. With microbial agent, the mean concentration of $COD_{Mn}$ and SS of second-stage digester effluent were 859mg/L, 2,405mg/L respectively. Consequently, microbial agent(Bio-dh) increased the removal efficiency of $COD_{Mn}$ and SS about 47.6% and 50.8%, respectively.

  • PDF

Physiochemical and Microbiological Changes of the Fermented Dandelion (Taraxacum officinale) Extracts with Raw Sugar (당 첨가 민들레(Taraxacum officinale) 발효 추출물의 발효과정 중 이화학적 및 미생물학적 변화)

  • Kim, Kyung-Min;Kim, Young-Nam;Choi, Byoung-Kon;Oh, Deog-Hwan
    • Food Science and Preservation
    • /
    • v.19 no.1
    • /
    • pp.131-137
    • /
    • 2012
  • This study was carried out to investigate the physiochemical and microbiological changes of dandelion during fermentation. Thirty and fifty percentage raw sugar groups (SFE30 and SFE50) were introduced into dandelions and fermented for 120 days at $15-20^{\circ}C$. This study was conducted to investigate the utilization of sucrose on lactic acid bacteria from dandelions and their effect on the pH, titratable acidity, microorganism and formation of organic acids in dandelions during fermentation. The number of lactic acid bacteria increased remarkably up to 15 days of fermentation and then decreased rapidly thereafter. The maximum number of lactic acid bacteria, 7.9 log CFU/mL was reached at pH 4.17 and the pH of dandelion showed a slight decrease during fermentation and decreased steadily up to 90 days to reach an optimum pH of 4.0. The titratable acidity of dandelions fermented increased during fermentation. The concentration of organic acid, amino acid and free sugar in SFE30 was higher than both SFE50 and DWE. The results of dandelions fermented were remarkably retarded in the 50% raw sugar group compared to the 30% raw sugar group.

Investigation into influence of sound absorption block on interior noise of high speed train in tunnel (터널 내부 도상 블록형 흡음재의 고속철도차량 내부 소음에 미치는 영향에 대한 고찰)

  • Lee, Sang-heon;Cheong, Cheolung;Lee, Song-June;Kim, Jae-Hwan;Son, Dong-Gi;Sim, Gyu-Cheol
    • The Journal of the Acoustical Society of Korea
    • /
    • v.37 no.4
    • /
    • pp.223-231
    • /
    • 2018
  • Recently, due to various environmental problems, blast tracks in tunnel are replaced with concrete tracks, but they have more adverse effects on noise than blast tracks so that additional noise measures are needed. Among these measures, sound-absorbing blocks start to be used due to its easy and quick installation. However, the performance of sound absorption blocks need to be verified under real environmental and operational conditions. In this paper, interior noise levels in KTX train cruising in Dalseong tunnel are measured before and after the installation of sound-absorbing blocks and the measured data are analyzed and compared. Additionally, noise reduction are estimated by modeling the high speed train, the tunnel and absorption blocks. Measurement devices and methods are used according to ISO 3381 and the equivalent sound pressure levels during the cruising time inside the tunnel are computed. In addition to overall SPLs(Sound Pressure Levels), 1/3-octave-band levels are also analyzed to account for the frequency characteristics of sound absorption and equipment noise in a cabin. In addition, to consider the effects of train cruising speeds and environmental conditions on the measurements, the measured data are corrected by using those measured during the train-passing through the tunnels located before and behind the Dalseong tunnel. Analysis of measured results showed that the maximum noise reduction of 6.8 dB (A) can be achieved for the local region where the sound-absorbing blocks are installed. Finally, through the comparison of predicted 1/3-octave band SPLs for the KTX interior noise with the measurements, the understanding of noise reduction mechanism due to sound-absorbing blocks is enhanced.

Studies on the Physiological Chemistry of the Spring Growth Habits in Naked Barley V. Changes in the Isozyme Patterns and Activities of Peroxidase During the Differentiation (과맥의 파성에 대한 생리화학적 연구 V. 유수의 분화, 발육과정중 Peroxidase의 활성 및 Isozyme Pattern)

  • 최선영;이강수;박기훈
    • KOREAN JOURNAL OF CROP SCIENCE
    • /
    • v.31 no.3
    • /
    • pp.375-382
    • /
    • 1986
  • This study was carried out to obtain the basic information for the clarification of spring growth habits mechanism of naked barleys. The isozyme patterns and activities of peroxidase in the young spike and leaf blade were analyzed during the differentiation and development of young spike. The characteristic differences between the normal and rosetted type were in c and g isozymes in young spike, and in i isozyme in the leaf blade. In the normal type, c and i isozymes disappeared at the stage of spi-kelet differentiation, g isozyme at the stage of flolet differentiation. But, in the rosetted type, those three isozymes remained in dark stained condition until the time of final sampling. Especially, those three isozymes were higher in the rosetted type than those in the normal type even at the stage of bract differentiation(BDS), just prior to the reproductive stage. The activities of peroxidase decreased slowly after BDS in the young spike and leaf blade in the normal type, While, in the rosetted type, increased linearly, and the degree of increasing was remarkable in the young spike. It was interesting that the degree of activities in young spike was higher in the rosetted type than that in the normal type even at BDS. From the above results, the remarkable differences of the isozyme patterns and activities at BDS between the normal and rosetted type were considered to be the physiological expression of the varieties concerned with the degree of spring growth habits.

  • PDF

Physicochemical Characteristics of the Sorghum(Sorghum bicolor L. Moench) Powder following Low Temperature-Microparticulation (저온초미분쇄에 따른 수수가루의 이화학적 특성)

  • Kim, Hyun-Young;Seo, Hye-In;Ko, Jee-Yeon;Kim, Jung-In;Lee, Jae-Saeng;Song, Seuk-Bo;Jung, Tae-Wook;Kim, Ki-Young;Kwak, Do-Yeon;Oh, In-Seok;Jeong, Heon-Sang;Woo, Koan-Sik
    • The Korean Journal of Food And Nutrition
    • /
    • v.25 no.3
    • /
    • pp.656-663
    • /
    • 2012
  • Two sorghum(Sorghum bicolor L. Moench cv. Hwanggeumchal-susu and Miryang 3) samples were milled using different milling methods, and their physicochemical properties were tested. Particle size was classified into five groups such as pin mill and low temperature-microparticulation(LTM; 10,000, 20,000, 30,000, and 40,000 rpm). The water absorption index (WAI), water solubility index(WSI), and a rapid Visco analyzer(RVA) were used to examine particle size distribution and color differences. Particle size of sorghum flour prepared using LTM was lower than that prepared using a pin mill. Particle size was further reduced by successive dry milling of the LTM flour. Lightness of colored pigments increased when particle size decreased. The WAI of Miryang 3 pin milling(M1) flour was the lowest after LTM, and WSI was higher in the order of M2, M3, M4, and M5. LTM sorghum flour had significantly higher pasting viscosity, as determined using a rapid Visco analyzer. LTM Miryang 3 sorghum flour(M2~M5) flour showed lower breakdown viscosity and higher final viscosity compared to those of M1 flour, resulting in an increased setback value.

Design Evaluation Model Based on Consumer Values: Three-step Approach from Product Attributes, Perceived Attributes, to Consumer Values (소비자 가치기반 디자인 평가 모형: 제품 속성, 인지 속성, 소비자 가치의 3단계 접근)

  • Kim, Keon-Woo;Park, Do-Hyung
    • Journal of Intelligence and Information Systems
    • /
    • v.23 no.4
    • /
    • pp.57-76
    • /
    • 2017
  • Recently, consumer needs are diversifying as information technologies are evolving rapidly. A lot of IT devices such as smart phones and tablet PCs are launching following the trend of information technology. While IT devices focused on the technical advance and improvement a few years ago, the situation is changed now. There is no difference in functional aspects, so companies are trying to differentiate IT devices in terms of appearance design. Consumers also consider design as being a more important factor in the decision-making of smart phones. Smart phones have become a fashion items, revealing consumers' own characteristics and personality. As the design and appearance of the smartphone become important things, it is necessary to examine consumer values from the design and appearance of IT devices. Furthermore, it is crucial to clarify the mechanisms of consumers' design evaluation and develop the design evaluation model based on the mechanism. Since the influence of design gets continuously strong, various and many studies related to design were carried out. These studies can classify three main streams. The first stream focuses on the role of design from the perspective of marketing and communication. The second one is the studies to find out an effective and appealing design from the perspective of industrial design. The last one is to examine the consumer values created by a product design, which means consumers' perception or feeling when they look and feel it. These numerous studies somewhat have dealt with consumer values, but they do not include product attributes, or do not cover the whole process and mechanism from product attributes to consumer values. In this study, we try to develop the holistic design evaluation model based on consumer values based on three-step approach from product attributes, perceived attributes, to consumer values. Product attributes means the real and physical characteristics each smart phone has. They consist of bezel, length, width, thickness, weight and curvature. Perceived attributes are derived from consumers' perception on product attributes. We consider perceived size of device, perceived size of display, perceived thickness, perceived weight, perceived bezel (top - bottom / left - right side), perceived curvature of edge, perceived curvature of back side, gap of each part, perceived gloss and perceived screen ratio. They are factorized into six clusters named as 'Size,' 'Slimness,' 'No-Frame,' 'Roundness,' 'Screen Ratio,' and 'Looseness.' We conducted qualitative research to find out consumer values, which are categorized into two: look and feel values. We identified the values named as 'Silhouette,' 'Neatness,' 'Attractiveness,' 'Polishing,' 'Innovativeness,' 'Professionalism,' 'Intellectualness,' 'Individuality,' and 'Distinctiveness' in terms of look values. Also, we identifies 'Stability,' 'Comfortableness,' 'Grip,' 'Solidity,' 'Non-fragility,' and 'Smoothness' in terms of feel values. They are factorized into five key values: 'Sleek Value,' 'Professional Value,' 'Unique Value,' 'Comfortable Value,' and 'Solid Value.' Finally, we developed the holistic design evaluation model by analyzing each relationship from product attributes, perceived attributes, to consumer values. This study has several theoretical and practical contributions. First, we found consumer values in terms of design evaluation and implicit chain relationship from the objective and physical characteristics to the subjective and mental evaluation. That is, the model explains the mechanism of design evaluation in consumer minds. Second, we suggest a general design evaluation process from product attributes, perceived attributes to consumer values. It is an adaptable methodology not only smart phone but also other IT products. Practically, this model can support the decision-making when companies initiative new product development. It can help product designers focus on their capacities with limited resources. Moreover, if its model combined with machine learning collecting consumers' purchasing data, most preferred values, sales data, etc., it will be able to evolve intelligent design decision support system.

동서간 중소기업 협력체제 구축 방안

  • Han, Jang-Hui
    • Journal of Global Scholars of Marketing Science
    • /
    • v.2
    • /
    • pp.17-37
    • /
    • 1998
  • 중소기업간 협력 활동은 사업의 전체 혹은 일정 부분에 대하여 분업이나 협업의 관계를 맺는 공동사업의 형태로 나타난다. 기업간 연결의 강도에 따라 기업들간에 형성되는 분업과 협업의 관계를 시장형, 중간조직형, 위계조직형으로 구분할 때, 중소기업간 공동사업은 중간조직형에 속하는 일종의 기업간 네트워크라고 볼 수 있다. 물론 네트워크형의 협력관계를 추진하는 방식도 업무제휴, 지분제휴, 합작투자, 컨소시엄 등으로 다양하다. 그러나 완전한 자본적 통합에 따른 위계적 조직과는 달리 참여기업들이 독립성을 유지하면서, 네트워크 밖의 기업에 대해 경쟁우위를 확보하기 위해 형성한다는 공통점을 가지고 있다. 기업간 협력관계를 통해 참여 기업들이 얻을 수 있는 혜택에 관한 기존연구들은 크게 두 가지로 나누어 볼 수 있다. 하나는 기업의 생산함수를 중심으로 그 이점을 파악하는 것이고 다른 하나는 관계의 종류에 따라 기업간 거래관계를 관리하는 소위 거래비용의 효율성을 중심으로 혜택을 파악하는 접근방법이다. 전자의 접근방법을 따를 때, 기업간 협력의 근본 유인은 규모의 경제(혹은 비경제), 범위의 경제, 집적의 경제, 구도의 경제 등이 협력관계에서 발생하는 혜택의 근본 원천이다. 기술과 제도의 발전, 시장과 경쟁환경의 변화에 따른 기업간 협력의 필요성은 갈수록 증대되고 있다. 소비자들의 요구는 매우 개성화 다양화되고 종합화되는 추세이다. 더불어 기술개발의 비용이 큰 폭으로 증가하고 있으며, 경쟁의 격화로 기술 및 제품의 진부화도 급속도로 이루어지고 있다. 세계화 상품고도화 서비스산업화 정보화 등으로 특징지워지는 새로운 경쟁환경 아래에서 장기적으로 기업의 경쟁력을 향상시키기 위해서는 시장중심적인 관점에서 형성된 기업간 전략적 연계를 바탕으로, 정보의 집적을 통해 다양한 생산성 향상 혹은 관계효율성 향상의 경제를 추구하는 것이 필연적 전제 조건이 되었다. 기업간 경쟁보다는 최종제품의 생산과 판매를 위해 형성된 기업네트워크간의 경쟁이 중시되는 시대인 것이다. 동서간(東西間) 중소기업(中小企業)의 협력(協力)을 새삼스럽게 논의하는 것은 다분히 정치적이라는 느낌을 준다. 경제적인 관점에서 실익이 있음에도 불구하고 동서간 중소기업의 협력이 이루어지지 못하고 있다면, 그 이유는 기업정보의 수집과 유통상의 문제이거나 문화나 기업관행에 대한 잘못된 선입관에서 비롯된 관계 관리비용 계산상의 문제일 것이다. 현실적으로 이 가능성은 매우 낮다. 산업의 발전 정도나 연관성에 있어서 동서축보다는 남북축을 따라 기업간 협력이 이루어질 수 밖에 없는 우리나라의 현재 상황이 동서간보다는 남북간 경제교류를 유도하고 있는 것이다. 동서간 중서기업 협력체제의 구축에 대한 논의가 본질적으로 정치적 관심에서 비롯되었다는 전제 하에, 구축의 방안을 논의하고자 한다. 경제적으로도 타당하면서 정치적으로 관심을 유발할 수 있는 협력체제 구축방안으로, 기업간 네트워크의 조직 주체로서 최근에 논의되고 있는 새로운 형태의 마케팅회사를 동서간에 공동으로 설립할 것을 제안한다. 영구 지속적 공동사업관계보다는 프로젝트별 공동사업을 전제로 기업들 사이의 효과적인 네트워크를 형성함으로써 일종의 가상적 기업을 결성할 필요가 있다. 이러한 기업간 네트워크 형성의 실행주체가 될 수 있는 새로운 마케팅 전문기업의 형태로는 공동회사(空洞會社)(hollow company), 종합상사(綜合商社)(General Trading Company), 거래형 마케팅회사(Marketing Exchange Company), 변환형 마케팅회사(Marketing Coalition Company) 등을 들 수 있다. 양 지역에서는 소비자환경과 기술환경의 특성 및 양 지역의 경제에 대한 파급효과를 고려하여 가장 적합한 마케팅회사의 유형은 선택하여 육성하고, 이를 중심으로 강력한 양 지역 및 다른 지역에 입지한 기업간의 네트워크를 구축하여야 한다. 마케팅회사를 설립하고 완전한 마케팅 서비스를 제공할 수 있도록 육성하기 위해서는 많은 투자가 필요하다. 마케팅회사의 핵심기능 분야인 금융부문, 정보부문, 영업조직 등은 모두 막대한 투자를 필요로하는 기능영역이다. 정보부문은 기술의 발전과 범세계적인 정보관련기관과의 제휴를 통해 독자적인 구축이 어느 정도 가능하나, 영업조직의 구축을 위해서는 기존업체와의 연대가 필수적인 것으로 판단된다. 지속적으로 효과적인 기업간 네트워크를 형성하고 유지하기 위해서는 또한 기업간 관계를 관리하는 방식과 제도 및 수단에 대한 연구가 필요하다. 양 지역 산 학 관의 공동노력을 통해서 새로운 경제 환경에 가장 적합한 기업 형태로 제시된 바 있는 마케팅 전문회사 중심의 기업간 네트워크를 성공적으로 구축한다면, 양 지역 및 국가 경제의 지속적인 동력원이 될 수 있을 것이다

  • PDF

Evaluation of Performance Based Design Method of Concrete Structures for Various Climate Changes (다양한 기후변화에 따른 콘크리트 구조물의 성능중심형 설계 평가)

  • Kim, Tae-Kyun;Shim, Hyun-Bo;Ahn, Tae-Song;Kim, Jang-Ho Jay
    • Journal of the Korean Recycled Construction Resources Institute
    • /
    • v.1 no.1
    • /
    • pp.8-16
    • /
    • 2013
  • Currently, global warming has advanced by the usage of fossil fuels such as coal and petroleum. and the atmosphere temperature in the world of 100 years(1906~2005) has been risen $0.74^{\circ}C{\pm}0.18^{\circ}C$, IPCC announced that the global warming effect of last decade was nearly doubled compared to the changes($0.07^{\circ}C{\pm}0.02^{\circ}C$/10year) in the past 100 years. Moreover, due to the global warming, heat wave, heavy snow, heavy rain, super typhoon, were caused and are increasing to happen in the world continuously causing damages and destruction of social infrastructures, where concrete structures are suffering deterioration by long-term extreme climate changes. to solve these problems, the new construction technology and codes are necessary. In this study, to solve these problems, experiments on a variety of cases considering the temperature and humidity, the main factors of climate factors, were performed, and the cases are decided by temperature and humidity. The specimens were tested in compressive strength test and split tensile test by the curing age(3,7,28 days) morever, performance based design(PBD) method was applied by using the satisfaction curve developed from the experiment date. PBD is the design method that gathers the current experimental analysis and past experimental analysis and develops the material properties required for the structure, and carries out the design of concrete mix, and it is recently studied actively worldwide. Also, it is the ultimate goal of PBD to design and perform on structures have sufficient performance during usage and to provide the problem solving for various situations, Also, it can achieve maximum effect in terms of functionality and economy.

A Study on Scenario to establish Coastal Inundation Prediction Map due to Storm Surge (폭풍해일에 의한 해안침수예상도 작성 시나리오 연구)

  • Moon, Seung-Rok;Kang, Tae-Soon;Nam, Soo-Yong;Hwang, Joon
    • Journal of Korean Society of Coastal and Ocean Engineers
    • /
    • v.19 no.5
    • /
    • pp.492-501
    • /
    • 2007
  • Coastal disasters have become one of the most important issues in every coastal country. In Korea, coastal disasters such as storm surge, sea level rise and extreme weather have placed many coastal regions in danger of being exposed or damaged during subsequent storms and gradual shoreline retreat. A storm surge is an onshore gush of water associated with a tow pressure weather system, typically in typhoon season. However, it is very difficult to predict storm surge height and inundation due to the irregularity of the course and intensity of a typhoon. To provide a new scheme of typhoon damage prediction model, the scenario which changes the central pressure, the maximum wind radius, the track and the proceeding speed by corresponding previous typhoon database, was composed. The virtual typhoon scenario database was constructed with individual scenario simulation and evaluation, in which it extracted the result from the scenario database of information of the hereafter typhoon and information due to climate change. This virtual typhoon scenario database will apply damage prediction information about a typhoon. This study performed construction and analysis of the simulation system with the storm surge/coastal inundation model at Masan coastal areas, and applied method for predicting using the scenario of the storm surge.