• Asian-Australasian Journal of Animal Sciences
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• 제10권6호
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• pp.571-574
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• 1997

Attempts were made in the laboratory to produce bypass fat using acid oil by precipitation and fusion methods. The degree of saponification by both of these methods was above 80 percent. Where heating facilities are not available, precipitation method could be used, otherwise, fusion method of bypass fat production is found to be more convenient, especially for commercial scale operations as handling of large volume of solutions is eliminated. Bypass fat thus produced was tested in vitro for rumen fermentation. Incorporation of acid oil in the incubation medium reduced TVFA conc. from 127.06 to 124.09 mM/l SRL and increased ammonia-N levels from 210.50 to 223 mg/l SRL indicating that the microbial activity was affected on incorporation of acid oil in the incubation medium. However, incorporation of bypass fat in the incubation medium did not significantly affect TVFA conc. as well as ammonia-N levels. In another experiment, nine rumen fistulated sheep in three groups of three each were fed bypass fat at two different levels. Dry matter disappearance in 24 h from the nylon bags suspended in the rumen of animals under different groups was found to be $47.74{\pm}1.10$, $47.55{\pm}0.21$ and $50.74{\pm}1.11$ in group I (control), group II (fed bypass fat 50 g/day) and group III (fed bypass fat 100 g/day), respectively. These studies indicated that it is possible to produce bypass fat from acid oils, a by-product of oil refining process, and its feeding did not affect rumen fermentation.

• 대한조선학회논문집
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• 제50권5호
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• pp.334-342
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• 2013

In this paper, we analyze the procedure of the design manager for the enhancement of the hull production design process by use of the simulation method. Normally, design manager assigns design jobs according to various methods and estimates the corresponding results. When the construction drawing which is the output of the detail design where a design is dealt by zones, the design manager identifies blocks and analyzes their work difficulties, and assigns jobs to design engineers who are different in capabilities. These processes including the design engineer who can be modeled with man-hours evaluation model are represented in detail as a simulation model. As the high-level modeling for the discrete-event system, we use Event Graph model. And we implemented the simulation using Simkit which is open simulation engine for the discrete-event system. We made the simulation scenario to be written by a user in the scenario generator which is separated from the simulation model, and made the simulation result to be visualized in the form of Gantt chart in a Web. In the scenario of the irregular issuance for various construction drawings which contain different numbers of blocks, we performed the Monte-Carlo simulation according to various assignment methods to find the assignment result that satisfies the mid-term schedule.

• 한국세라믹학회지
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• 제47권2호
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• pp.169-176
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• 2010

The Fe-treated CNT/$TiO_2$ photocatalysts mixed with anatase and rutile phase have been developed for the decomposition of non-biodegradable different organic dyes like methylene blue (MB), rhodamine B (Rh.B), and methyl orange (MO) in two conditions as ultraviolet and visible light respectively. The results indicate that all the Fe-CNT/$TiO_2$ composites proved to be more efficient photocatalysts since degradation of MB at higher reaction rates, tthe decomposition rate of different dyes increases with an increase of $Fe^{3+}$ concentration in composites the highest rate of decomposition of different dyes was noted under UV irradiation. These results can indicate that the large CNT network is facilitate the electron transfer and strongly adsorb dye molecules on the texted photocatalysts, iron is reactive in the photo-Fenton process resulting in high production of OH radicals and also high activity of the photocatalyst. And Fe particles can generate more photoinduced electrons to conduction band of $TiO_2$ under visible light irradiation. The composites of Fe-CNT/$TiO_2$ photocatalysts synthesized by a sol-gel method were characterized by BET, TEM, SEM, XRD and EDX.

• 한국축산식품학회지
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• 제40권3호
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• pp.323-337
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• 2020

This study was conducted to investigate whether adding different levels of raw or differently processed chickpea into different diets of laying quails affected live weight, feed intake, feed efficiency, egg weight and internal and external egg quality. Chickpea was used as raw, autoclaved or microwave-processed, and it was involved in the diets on two different levels (20% and 40%). The sample was divided into 7 groups including the control, 20% and 40% raw, 20% and 40% autoclaved, and 20% and 40% microwave-processed groups. 336 ten-week-old female laying quails were used in the study, and the experiment continued for 19 weeks. In the study, the differences among the groups were insignificant in terms of live weight, feed intake, feed efficiency, egg weight and egg quality characteristics such as shell thickness, shell weight, yolk weight, yolk color and albumin index. The differences were significant in terms of the shape index, Haugh unit (p<0.05) and yolk index (p<0.01). Consequently, it was observed that different thermal processes on chickpeas did not usually have a significant effect on the yield performance of the quails, and the results that were obtained were similar to the other groups. However, it was determined that some egg quality characteristics were affected by the autoclaving and microwaving processes. Between the thermal processes, it may be stated that autoclaving provided better results.

• 기술경영경제학회:학술대회논문집
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• 기술경영경제학회 1999년도 제16회 동계학술발표회 논문집
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• pp.123-158
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• 1999

This study examines the differences in the various characteristics of the firms along their growth stage based on the survey data of 2,515 Korean ventures. Venture characteristics include KSFs(Key Success Factors), environment attributes of their product markets, CEO roles, the use of OPR(Other Peoples Resource). Growth stage of the ventures are classified by their dominant management problems: foundation, the market launch of the first proprietary product or service, The Outset of second generation product or service, and the Initial Public Offering (IPO) and stabilization. The results of this study show substantial differences in many aspects among firms at different growth stages. Although common KSFs exist, KSFs are changing as the venture evolves. Differences in KSFs and environmental attributes along growth stage require CEO to do different role in business process. Different kinds and amounts of external resources are needed according to their growth stage. However, almost all of external resources are offered to ventures in later stage. Entrepreneurs need to change their role, as their firms grow, from visioning and strategic role to marketing and production emphasized role. Based on the results, this study suggests a number of new government policies and future research ideas. Other implications and limitations of this study are also noted.

• Korean Chemical Engineering Research
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• 제59권3호
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• pp.345-358
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• 2021

본 연구에서는 액화천연가스(LNG; liquefied natural gas) 재기화 과정에서 버려지는 냉열을 회수하는 방법으로 액화 공기를 생산하는 공정을 개발하였다. 액화 공기는 LNG 수출국으로 운송하여 천연가스 액화를 위한 냉매를 부분적으로 대체하는 용도로 활용될 수 있다. 이를 위하여, 액화 공기는 LNG 운반선에 저장 가능한 압력을 만족하여야 한다. 따라서, 가장 널리 사용되는 멤브레인 탱크로 액화 공기를 운송하기 위해 약 1.3 bar에서 공기가 액체 상태로 존재할 수 있도록 설계하였다. 제안한 공정에서, 공기는 LNG와의 열교환 이후 추가적인 질소 냉매 사이클과의 열교환을 통해 과냉된다. LNG 운반선의 최대 용량만큼 액화 공기를 생산할 때 운송비용 측면에서 가장 경제적일 수 있으며, 천연가스 액화공정에서 활용할 수 있는 냉열이 많아지게 된다. 이를 비교하기 위하여, 동일한 1 kg/s의 LNG 공급 조건 하에서 기존 공정을 이용한 Base case와 제안공정 내 유입 공기 유량을 각각 0.50 kg/s, 0.75 kg/s, 1.00 kg/s으로 하는 Case1, Case2, Case3를 구성하고 열역학적 및 경제적 측면에서 분석하였다. 액화 공기 생산량이 많을수록 1kg의 생산량 당 더 많은 에너지가 요구되는 경향을 보였으며 Case3는 Base case 대비 0.18 kWh 높게 나타났다. 그 결과 Case3의 액화 공기 1 kg 당 생산 비용이 $0.0172 더 높게 나타났다. 그러나 액화 공기의 생산량이 증가함에 따라 1 kg 당 운송 비용이 $0.0395 감소하여 전체 비용 측면에서 Case3는 Base case에 비해 1 kg 당 $0.0223 적은 비용으로 액화 공기를 생산 및 운송할 수 있음을 확인하였다.

• 사물인터넷융복합논문지
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• 제6권3호
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• pp.75-80
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• 2020

최근의 IoT 센서의 소형화와 센서의 소형화로 인하여 다른 센서 및 구조물들과의 간섭 및 견고성을 고려하여 더욱 복잡해 지고 있다. 최근 3D 프린팅 기술은 센서 직접 제작이나, 센서 소자를 포함하는 기구를 만드는 분야에 다양하게 적용이 되고 있다. 그 중에서, fused deposition modeling(FDM) 기술은 장비 및 소재의 가격이 상당히 저렴하며, IoT 기기의 제작이 활용이 가능한 가장 유력한 기술중에 하나이다. 그런 FDM 프린팅 기술은 플라스틱 소재 기반의 필라멘트를 녹여서 적층하여 3D 형상을 만들어 내는 기술이며, 최근에 특허 종료와 아울러 오픈 소스 기반의 저가형 프린터가 개발됨으로 일반인들에게도 널리 사용되고 있다. 이런 FDM 기술을 이용하여 출력된 출력물에 있어서 기계적 물성치는 소재의 종류와 다양한 공정 변수들에 의해서 영향을 받는다. 그 중에서도 내부 채움(infill)은 기계적 물성치에도 큰 영향을 주면, 출력 시간에도 영향을 준다. 따라서 본 논문에서 내부 채움과 기계적 물성치 및 출력 시간 사이의 관계를 규명하여, 기계 기구물을 제작할 때 출력 시간과 기계적 물성치를 고려한 최적의 내부 채움 조건 선정 방법을 제시하고자 한다. 제시된 방법을 증명하고자, 다른 공정은 모두 고정하고, 내부 채움 조건만을 변경한 인장 시편을 제작하고, 제작된 시편을 인장 실험을 통하여 내부 채움에 따른 출력물의 기계적 물성치를 비교 분석하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.86.1-86.1
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• 2015

As the feature size of Si-based semiconductor shrinks to nanometer scale, we are facing to the problems such as short channel effect and leakage current. One of the solutions to cope with those issues is to bring III-V compound semiconductors to the semiconductor structures, because III-V compound semiconductors have much higher carrier mobility than Si. However, introduction of III-V semiconductors to the current Si-based manufacturing process requires great challenge in the development of process integration, since they exhibit totally different physical and chemical properties from Si. For example, epitaxial growth, surface preparation and wet etching of III-V semiconductors have to be optimized for production. In addition, oxidation mechanisms of III-V semiconductors should be elucidated and re-growth of native oxide should be controlled. In this study, surface preparation methods of various III-V compound semiconductors such as GaAs, InAs, and GaSb are introduced in terms of i) how their surfaces are modified after different chemical treatments, ii) how they will be re-oxidized after chemical treatments, and iii) is there any effect of surface orientation on the surface preparation and re-growth of oxide. Surface termination and behaviors on those semiconductors were observed by MIR-FTIR, XPS, ellipsometer, and contact angle measurements. In addition, photoresist stripping process on III-V semiconductor is also studied, because there is a chance that a conventional photoresist stripping process can attack III-V semiconductor surfaces. Based on the Hansen theory various organic solvents such as 1-methyl-2-pyrrolydone, dimethyl sulfoxide, benzyl alcohol, and propylene carbonate, were selected to remove photoresists with and without ion implantation. Although SPM and DIO3 caused etching and/or surface roughening of III-V semiconductor surface, organic solvents could remove I-line photoresist without attack of III-V semiconductor surface. The behavior of photoresist removal depends on the solvent temperature and ion implantation dose.

• 한국대기환경학회지
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• 제23권1호
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• pp.110-124
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• 2007

In this study, the control efficiency of odorous compounds was measured from diverse control process units of 14 individual companies located within the Ban-Wall industrial complex of Ansan city, Korea (January to July 2005), To quantify the control efficiency levels of major odorous compounds, we collected odor samples from both the front and rear side of 17 control process units ($N=17{\times}2=34$). If the control efficiency is compared for each of 32 compounds between different process units, wet scrubber (WS) was found to be the most effective unit in terms of the sum of pollutants showing the positive control signals. Although the WS system shows generally a good control pattern for VOC, it is not the case for most index odorous pollutants; only 3 out of 12 index compounds were found to show positive control efficiencies. The results of the study also indicated that the control efficiency differ greatly between different industrial sectors and/or control process types. In the case of leather industry, carbonyl compounds were found to exhibit the highest control efficiency with its values varying from 19 to 90%. On the other hand, in the case of metal production sector, VOC recorded the maximum control efficiency with values varying from 18 to 79%. According to this study, most air pollution control facilities operated in most companies show fairly poor control efficiencies for most malodor compounds. Hence, to obtain best control efficiency of odorous pollutant emission, acquisition of better information on source characteristics and establishment of effective control technologies are highly demanding.

• Plant Biotechnology Reports
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• 제5권3호
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• pp.265-271
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• 2011

The cultivated potato as well as its tuber-bearing relatives are considered model plants for cell and tissue culture, and therefore for exploiting the genetic variation induced by in vitro culture. The association between molecular stability and tissue culture in different genetic backgrounds and ploidy levels has already been explored. However, it still remains to be ascertained whether somaclonal variation differs between callus-derived chromosome-doubled and undoubled regenerants. Our research aimed at investigating, through amplified fragment length polymorphism (AFLP) markers, the genetic changes in marker-banding patterns of diploid and tetraploid regenerants obtained from one clone each of Solanum bulbocastanum Dunal and S. cardiophyllum Lindl (both 2n = 2x = 24) and tetraploids from cultivated S. tuberosum L. (2n = 4x = 48). Pairwise comparisons between the banding patterns of regenerants and parents allowed detecting considerable changes associated to in vitro culture both at diploid and tetraploid level. The percentages of polymorphic bands between diploid and tetraploid regenerants were, respectively, 57 and 69% in S. bulbocastanum and 58 and 63% in S. cardiophyllum. On average, the frequencies of lost parental fragments in regenerants were significantly higher than novel bands both in S. bulbocastanum (48 vs. 22%) and S. tuberosum (36 vs. 18%) regenerants. By contrast, in S. cardiophyllum, a similar incidence of the two events was detected (32 vs. 29%). Our results revealed that structural changes after tissue culture process strongly affected the genome of the species studied, but diploid and tetraploids regenerated plants responded equally.