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A Study on Development of Alternative Non-aqueous Cleaning Agents to Ozone Depletion Substances and its Field Application (오존파괴물질 대체 비수계세정제 개발 및 현장 적용 연구)

  • Park, Yong-Bae;Bae, Jae-Heum;Lee, Min-Jae;Lee, Jong-Gi;Lee, Ho-Yeoul;Bae, Soo-Jung;Lee, Dong-Kee
    • Clean Technology
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    • v.17 no.4
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    • pp.306-313
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    • 2011
  • Flux or solder is used in soldering process for manufacturing electronic parts such as printed circuit boards (PCB). After soldering process, residual flux and solder paste on the parts should be removed since their residuals could cause performance degradation or failure of parts due to their corrosion and electric leakage. Ozone depletion substances such as 1,1,1- trichloroethane (TCE) and HCFC-141b have widely been using for removal of residual flux and solder paste after soldering process In manufacturing of electronic parts until now. In this study, non-aqueous cleaning agents without flash point were developed and applied to industrial field for replacement of cleaning agents with ozone depletion. In order to develop non-aqueous cleaning agents without ethers, esters, fluoride- type solvents. And their physical properties and cleaning abilities were evaluated, and they were applied to industrial fields for cleaning of flux and solder on the PCB. And vacuum distillation apparatus were operated to determine their operating conditions and recycling yields for recycling of used cleaning agents formulated in this study. As a result of physical properties measurement of our formulated cleaning agents, they were expected to have good wetting and penetrating power since their surface tensions were relatively low as 18.0~20.4 dyne/$cm^2$ and their wetting indices are relatively large. And some cleaning agents holding fluoride-type solvents as their components did not have any flash point and they seemed to be safe in their handling and storage. The cleaning experimental results showed that some cleaning agents were better in their cleaning of flux and solder paste than 1,1,1-TCE and HCFC-141b. And industrial application results of the formulated cleaning agents for cleaning PCB indicated that they can be applicable to industry due to their good cleaning capability in comparison with HCFC-141b. The recycling experiments of the used formulated cleaning agents through a vacuum distillation apparatus also showed that their 91.9~97.5% could be recycled with its proper operating conditions.

Factors which Influence Customers' Intention to Switch from Call-Based Driver-for-hire Services to App-Based Driver-for-hire Services Based on Online to Offline (O2O) Business Model: Focusing on Kakao Driver service (콜 대리업체 서비스에서 O2O 방식이 적용된 대리운전 사업 모델로의 소비자 전환 의도에 관한 연구: 카카오 드라이버를 중심으로)

  • Kim, Daewon;Jeong, Hye Seung
    • The Journal of Society for e-Business Studies
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    • v.21 no.3
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    • pp.51-78
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    • 2016
  • Online-to-offline (O2O) commerce is the new trend that merges online commerce with traditional industries in various fields. The primary purpose of this paper is to find out which factors influence customers' intention to switch from call-based driver-for-hire services to O2O app-based services. This study used variables and factors based on Theory of Switching Intention, and Extended Unified Theory of Acceptance and Use of Technology in order to design research questions. We surveyed 500 users of call-based driver-for-hire services. According to the result of this study, dissatisfaction with the current call-based driver-for-hire services is estimated to be a significant factor that strengthens customers' intention to switch from the call-based driver-for-hire services to the app-based services. Loyalty to the previous call-based driver-for-hire services was not seen as a crucial motivator that causes customers to switch to the new O2O driver service. Switching cost also did not play a key role in explaining the relationship between dissatisfaction with the current call-based service and the intention to use the new app-based service. Performance expectancy, easiness in use, the level of user's knowledge or available assistance in relation to the use of app-based services, and expectancy for reasonable price was found to have meaningful impacts on customers' intention to switch from the call-based driver-for-hire services to the app-based services. Age, gender and user experience on the new service were found incapable of moderating the relationship between aforementioned factors which influence customers' choice of the app-based driver-for-hire service, and customers' intent to switch to the app-based service.

Changes in the in vitro Antioxidant and Antithrombosis Activities of Salicornia europaea According to Harvest Time (수확시기에 따른 함초의 항산화 및 항혈전 활성의 변화)

  • Kim, Mi-Sun;Lee, Jung-Nam;Seong, Ha-Jung;Kim, Deuk Hoi;Sohn, Ho-Yong
    • Journal of Life Science
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    • v.26 no.9
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    • pp.1033-1040
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    • 2016
  • In Korea, the aerial parts of the halophyte Salicornia europaea, known as hamcho, are used in salads in April–June and in oriental medicine in September–October In this study, with the aim of developing functional foods to aid blood circulation, hot water extract (HWE) and ethanol extract (EE) were prepared using hamcho harvested from the fields of Shinan, Jeonnam, Korea on 5th April (HWE-04, EE-04), 5th July (HWE-06, EE-06), 5th August (HWE-08, EE-08), 5th September (HWE-09, EE-09), and 5th October (HWE-10, EE-10), and their antioxidant and antithrombosis activities were evaluated. Among the HWEs, HWE-10 showed the highest concentration of total polyphenols and total flavonoids (22.4 and 17.6 mg/ml, respectively), and EE-09 had the highest concentration among the EEs (20.1 and 19.3 mg/ml, respectively). Among the HWEs and EEs, HWE-08 and EE-08 had the highest total sugar and reducing sugar content. In the antioxidation assay, HWE-10 and EE-09 showed strong reducing power, as well as DPPH, ABTS, and nitrite scavenging activities. The calculated RC50s of EE-09 against DPPH, ABTS, and nitrite were 578, 277, and 68.8 μg/ml, respectively. The antithrombosis activity assay revealed that HWE-04, HWE-06, EE-04, and EE-06 had anticoagulation activity against coagulation factors and that HWE-08, HWE-09, EE-08, and EE-09 expressed strong thrombin inhibitory activity, which was comparable to the antithrombosis activity of aspirin. In addition, EE-06 and HWE-08 exhibited strong aggregation inhibitory activities against human platelets. The results suggest that extract from hamcho harvested in particular periods and prepared using a defined solvent has strong potential as a novel food ingredient and an antioxidant and antithrombosis agent.

A Case Study of Angular Momentum of Trunk and Lower extremity when Performing Uchimata by Posture and Voluntary Resistance Levels of Uke in Korean Judo Olympian[III] (유도 올림피언 허벅다리걸기 기술발휘 시 받기의 자세와 저항수준에 따른 몸통과 하지의 각운동량 분석 사례연구[III])

  • Kim, Eui-hwan;Kim, Sung-sup;Chung, Chae-Wook
    • Korean Journal of Applied Biomechanics
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    • v.15 no.4
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    • pp.191-203
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    • 2005
  • It was to study a following research of "A Kinematical Traits Analysis when Performing Uchimata(inner thigh reaping throw) by Posture and Voluntary Resistance Levels(VRL) of Uke in Judo[1]" and. "A Case Study of Center of Gravity(COG) when Performing Uchimata(inner thigh reaping throw) by Posture and Voluntary Resistance Levels(VRL) of Uke in Judo[II]". The purpose of this study was to analyze an angular momentum of trunk and lower extremity when performing uchimata by two postures and voluntary resistance levels(VRL) of uke(reciver) in Judo. The subjects, who were one male judoka(YH) for 1992 Barcelona Olympic Games Olympian(silver medalist), was filmed on two S-VHS 16mm video cameras(60fields/sec.) through 3-dimensional motion analysis methods, that postures of uke were shizenhontai (straight natural posture:NP) and jigohontai (straight defensive posture:DP), VRL of uke were 0% and 100%, respectively. The variables were angular momentum of trunk, lower extremity of attacking leg and supporting leg of tori(the thrower). The data of this study collection were digitized by SIMI Motion Program computed the mean values and the standard deviation calculated for each variables. When performing uchimata according to each posture and VRL of uke and classifying. From the data analysis and discussion, the conclusions were as follows : Angular momentum of trunk when performing uchimata was showed the largest among another angular momenta, and the posture displayed more different than resistant of uke(reciver), but the pattern similar in judo. Angular momentum of trunk of X axis was the largest and Y, Z axis order. Angular momentum of attacking the thigh-leg when performing uchimata was showed the largest among another angular momenta, and the posture displayed more different than resistant of uke(reciver), X axis and Y axis similar, but angular momentum of Z axis of thigh-leg the largest, in kake(application) event in 0% resistance of DP than other variables. Angular momentum in X,Y axis of attacking the lower-leg when performing uchimata was showed that the resistance level displayed more different than posture, but Z axis the largest, in kake(E3) phase in 0% resistance of DP than other variables as same thigh-leg, and the largest from tsukuri(set-up:E2) to kake(E3) phase. X and Z axis Angular momentum of supporting the thigh-leg were similar, regardless of posture and resistance of uke, but Y axis was resistance level. Angular momentum of supporting the thigh-leg was showed the largest in X axis, increased from EO event to E2, and decreased in E3, and angular momenta of Y, X axis were showed the largest in kuzushi(balance breaking) phase when performing uchimata. Angular momentum of supporting the lower leg were similar pattern, regardless of posture and resistance of uke, in Y axis, resistance displayed more difficult the position in NP, and showed opposite angular momentum in tsukuri phase. In conclusion, angular momentum of trunk when performing uchimata was showed the largest, and pattern was similar, regardless of posture than resistant of uke(reciver), magnitude and direction were different each other, and uchimata was Ashi -waza(foot and leg techniques) division but important of trunk action.

Effect of Crop Yield and Soil Physical Properties to Application of Organic Resources in Upland (밭 토양에서 유기물 자원의 시용이 작물 수량 및 토양 물리성에 미치는 영향)

  • Han, Kyunghwa;Jung, Kangho;Cho, Heerae;Lee, Hyubsung;Ok, Junghun;Zhang, Yongseon;Kim, Gisun;Seo, Youngho
    • Journal of the Korea Organic Resources Recycling Association
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    • v.25 no.4
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    • pp.15-22
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    • 2017
  • Application of organic resources to agricultural land can increase crop yield by improving soil characteristics. The objective of this study was to evaluate effect of crop yield and soil physical properties including aggregate stability to application of organic resources in upland. The soybean was cultivated in a sandy loam field and a clay loam field located at Suwon and a sandy loam field located at Pyeongchang. The organic resources used in this study were rice straw compost (RSC), composted pig manure with sawdust (CPIG), composted poultry manure with sawdust (CPM), and cocopeat applied before sowing crop. Application rate of organic resources was determined based on carbon content and water content. The inorganic fertilizers were applied based on soil testing. In addition, the decomposition of RSC, CPIG, and cocopeat was characterized by isothermal incubation with sandy loam soil. The decomposition rate was highest for RSC followed by CPIG and cocopeat. Organic resource application increased yield of soybean, which effect was greater in clay loam than in sandy loam. In addition, increase in gas phase proportion by organic resource application was distinct in clay loam soil compared with sandy loam soil. In terms of aggregate stability, increasing effect was more obvious in sandy loam soils than in a clay loam soil. The highest yield was observed in RSC treatment plots for all the fields. Improvement of soybean yield and soil physical characteristics by cocopeat was not as much as that of the other organic resources. The results implied that RSC could be recommended for promoting aggregate stability and crop yield in upland cultivation.

Seed Potato Certification in Korea (한국의 씨감자 검역)

  • La Yong-Joon;Franckowiak J. D.;Brown W. M.
    • Korean journal of applied entomology
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    • v.16 no.3 s.32
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    • pp.163-170
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    • 1977
  • Potato diseases, especially mosaics and leaf roll, appear to reduce potato yield in Korea more than any other factor. A seed potato certification program was established at the Alpine Experiment Station (AES) in 1961 to produce high quality seed potatoes for distribution to Korean farmers. The present program for production of certified seed of Namjak (Irish Cobbler), the only variety recommended for spring plantings, is outlined. In 1976, approximately 10,000 MT of certified grade Namjak seed was produced by members of two Seed Producers Cooperatives in the Daekwanryeong area for distribution by the Office of Seed Production and Distribution (OSPD). The seed was inspected and certified by officers of the National Agricultural Products Inspection Office (NAPIO). Although the quality of the certified seed is far superior to that used by many farmers, the supply planted less than 1/5 of the 1977 potato crop. Certified seed of Shimabara, the variety recommended for autumn plantings, is not produced in Korea. The yield response of virus infected seed to improved cultural practices is poor. Therefore, an increase in potato acreage and yields appears to be possible only if more good quality seed is used by Korean farmers. A two or three fold increase in seed supply would be desirable. The volume of seed could be increased by expanding the production area and by improving yield in seed fields. More land is available in the alpine area and good seed potatoes could be grown in other parts of Korea. Planting better quality seeds and using better cultural pracitces would improve seed yields. Several techniques could be used to improve the quality of elite seed produced at AES. Changes in seed potato certification program should be made so that healthy seed stocks of new varieties can be released rapidly.

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The influence of magnet on tissue healing after immediate implantation in fresh extraction sites in dogs (성견에서 발치 후 즉시 식립 임플란트에 설치한 자석이 주위 조직에 미치는 영향)

  • Yu, Seok-Min;Cho, In-Ho;Shin, Soo-Yeon
    • The Journal of Korean Academy of Prosthodontics
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    • v.47 no.4
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    • pp.435-444
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    • 2009
  • Statement of problem: The clinical use of electric and electomagnetic fields for fracture healing applications began in the early 1970s. Since then, several technologies have been developed and shown to promote healing of fractures. Developments of these devices have been aided in recent years by basic research and several well controlled clinical trials not only in the medical field but in dentistry. Purpose: The purpose of this study was to compare alveolar bone reduction following immediate implantation using implants onto which magnets were attached in fresh extracted sockets. Material and methods: Four mongrel dogs were involved. Full buccal and lingual mucoperiosteal flaps were elevated and third and fourth premolars of the mandible were removed. Implants with magnets and implants without magnets were installed in the fresh extracted sockets and after 3 months of healing the animals were sacrificed. The mandibles were dissected and each implant sites were sampled and processed for histological examination. Results: The marginal gaps that were present between the implant and walls of the sockets at the implantation stage disappeared in both groups as a result of bone fill and resorption of the bone crest. The buccal bone crests were located apical of its lingual counterparts. At the 12 week interval the mean of marginal bone resorption in the control group was significantly higher than that of the magnet group. The majority of specimens in magnet group presented early bone formation and less resorption of the buccal marginal bone compared to the control group. Conclusion: Within the limitations of this study, it could be concluded that implants with magnets attached in the early stages of implantation may provide more favorable conditions for early bone formation and reduce resorption and remodeling of marginal bone.

Physicochemical Characteristics and Antioxidative Effects of Barley Soybean Paste (Doenjang) Containing Kelp Extracts (다시마 추출물을 첨가한 보리된장의 일반적 특성과 항산화 효과)

  • Oh, Se In;Sung, Jung Min;Lee, Kun Jong
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.43 no.12
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    • pp.1843-1851
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    • 2014
  • This study evaluated the quality characteristics and antioxidant activities of barley Doenjang (soybean paste) containing various contents (4, 12, and 20%) of kelp extracts. After 60 days of fermentation, pH, acidity, and viscosity of Doenjang were 5.80~6.86, 0.57~1.87%, and 4,913.3~9,333.3 cps, respectively, showing significant differences according to content of kelp extracts. Amino-type nitrogen contents was 902.60~921.90 mg%. For color values, L and b values increased significantly (P<0.001), whereas a value decreased slightly according to kelp extracts. DPPH radical scavenging effect ($IC_{50}$) for butylated hydroxyanisole ranged from 10.28 mg/mL to 23.23 mg/mL. DPPH radical scavenging effects of control was highest among the samples. The total polyphenol and flavonoid contents were 12.72~6.37 mg tannic acid equivalence/g, and $0.98{\sim}1.56{\mu}g$ rutin equivalence/g, respectively. Initial counts of total bacteria and lactic acid bacteria were 7.20~7.57 log CFU/g, and 4.20~4.71 log CFU/g respectively, showing significant difference according treatment and fermentation (P<0.05). In the sensory evaluation, 20% kelp extract Doenjang (5.6) showed higher overall acceptability than other samples (6.5) (P<0.01). Especially, umami taste (6.1) and texture (6.4) of 20% kelp extract Doenjang were higher than those of control (P<0.05). These results suggest that Doenjang containing kelp extracts, will be good for industrial fields.

Transmission Dose Estimation Algorithm for in vivo Dosimertry (투과선량을 이용한 생체내 (in vivo) 선량측정을 위한 알고리즘)

  • Yun, Hyong-Geun;Chie, Eui-Kyu;Huh, Soon-Nyung;Lee, Hyoung-Koo;Woo, Hong-Gyun;Shin, Kyo-Chul;Kim, Si-Yong;Ha, Sung-Whan
    • Journal of Radiation Protection and Research
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    • v.27 no.3
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    • pp.147-154
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    • 2002
  • Purpose : Measurement of transmission dose is useful for in vivo dosimetry of QA purpose. The objective of this study is to develope an algorithm for estimation of tumor dose using measured transmission dose for open radiation field. Materials and Methods : Transmission dose was measured with various field size (FS), phantom thickness (Tp), and phantom chamber distance (PCD) with a acrylic phantom for 6 MV and 10 MV X-ray. Source to chamber distance (SCD) was set to 150 cm. Measurement was conducted with a 0.6 co Farmer type ion chamber. Using measured data and regression analysis, an algorithm was developed lot estimation of expected reading of transmission dose. Accuracy of the algorithm was tested with flat solid phantom with various settings. Results : The algorithm consisted of quadratic function of log(A/P) (where A/P is area-perimeter ratio) and tertiary function of PCD. The algorithm could estimate dose with very high accuracy for open square field, with errors within ${\pm}0.5%$. For elongated radiation field, the errors were limited to ${\pm}1.0%$. Conclusion : The developed algorithm can accurately estimate the transmission dose in open radiation fields with various treatment settings.

Recent Developments in Space Law (우주법(宇宙法)의 최근동향(最近動向))

  • Choi, June-Sun
    • The Korean Journal of Air & Space Law and Policy
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    • v.1
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    • pp.223-243
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    • 1989
  • The practical application of modern space science and technology have resulted in many actual and potential gains of mankind. These successes have conditioned and increased the need for a viable space law regime and the challenge of space has ultimately led to the formation of an international legal regime for space. Space law is no longer a primitive law. It is a modern law. Yet, in its stages of growth, it has not reached the condition of perfection. Therefore, under the existing state of thing, we could carefully say that the space law is one of the most newest fields of jurisprudence despite the fact that no one has so far defined it perfectly. However, if space law can be a true jurisprudential entity, it must be definable. In defining the space law, first of all, the grasp of it's nature iis inevitable. Although space law encompasses many tenets and facets of other legal discriplines, its principal nature is public international law, because space law affects and effects law relating intercourse among nations. Since early 1960s when mankind was first able to flight and stay in outer space, the necessity to control and administrate the space activities of human beings has growingly increased. The leading law-formulating agency to this purpose is the United Nation's ad hoc Committee on Peaceful Uses of Outer Space("COPUOS"). COPUOS gave direction to public international space law by establishing the 1963 Declaration of Legal Principles Governing the Activities of the States in the Exploration and Use of Outer Space("1963 Declaration"). The 1963 Declaration is very foundation of the five international multilateral treaties that were established successively after the 1963 Declaration. The five treaties are as follows: 1) The Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space including Moon and other Celestial Bodies, 1967. 2) The Agreement on the Rescue of Astronauts, the Return of Astronauts, and the Return of Objects Launched into Outer Space, 1968. 3) The Convention on International Liability for Damage Caused by Space Objects, 1972. 4) The Convention on Registration of Objects Launched into Outer Space, 1974. 5) The Agreement Governing Activities of States on the Moon and Other Celestial Bodies: Moon Treaty, 1979. The other face of space law is it's commercial aspect. Space is no longer the sole domination of governments. Many private enterprise have already moved directly or indirectly into space activities in the parts such as telecommunications and space manufacturing. Since space law as the public international law has already advanced in accordance with the developments of space science and technology, there left only a few areas untouched in this field of law. Therefore the possibility of rapid growth of space law is expected in the parts of commerical space law, as it is, at this time, in a nascent state. The resources of the space environment are also commercially both valuable and important since the resources include the tangible natural resources to be found on the moon and other celestial bodies. Other space-based resources are solar energy, geostationary and geosynchronous orbital positions, radio frequencies, area possibly suited to human habitations, all areas and materials lending themselves to scientific research and inquiry. Remote sensing, space manufacturing and space transportation services are also another potential areas in which commercial. endeavors of Mankind can be carried out. In this regard, space insurance is also one of the most important devices allowing mankind to proceed with commercial space venture. Thus, knowlege of how space insurance came into existence and what it covers is necessary to understand the legal issues peculiar to space law. As a conclusion the writer emphasized the international cooperation of all nations in space activities of mankind, because space commerce, by its nature, will give rise many legal issues of international scope and concern. Important national and world-community interests would be served over time through the acceptance of new international agreements relating to remote sencing, direct television broadcasting, the use of nuclear power sources in space, the regularization of the activities of space transportation systems. standards respecting contamination and pollution, and a practical boundary between outer space and air space. If space activity regulation does not move beyond the national level, the peaceful exploration of space for all mankind will not be realized. For the efficient regulation on private and governmental space activities, the creation of an international space agency, similar to the International Civil Aviation Organization but modified to meet the needs of space technology, will be required. But prior to creation of an international organization, it will be necessary to establish, at national level, the Office of Air and Space Bureau, which will administrate liscence liscence application process, safety review and sale of launch equipment, and will carry out launch service.

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