• Title/Summary/Keyword: research process

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Reactive Ion Etching Process Integration on Monocrystalline Silicon Solar Cell for Industrial Production

  • Yoo, Chang Youn;Meemongkolkiat, Vichai;Hong, Keunkee;Kim, Jisun;Lee, Eunjoo;Kim, Dong Seop
    • Current Photovoltaic Research
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    • v.5 no.4
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    • pp.105-108
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    • 2017
  • The reactive ion etching (RIE) technology which enables nano-texturatization of surface is applied on monocrystalline silicon solar cell. The additional RIE process on alkalized textured surface further improves the blue response and short circuit current. Such parameter is characterized by surface reflectance and quantum efficiency measurement. By varying the RIE process time and matching the subsequent processes, the absolute efficiency gain of 0.13% is achieved. However, the result indicates potential efficiency gain could be higher due to process integration. The critical etch process time is discussed which minimizes both front surface reflectance and etching damage, considering the challenges of required system throughput in industry.

Interactive graphic simulation of research nuclear reactor dismantling process (연구용원자로 원격해체공정의 그래픽 전산모사)

  • 박영수;윤지섭;오원진;홍순혁
    • 제어로봇시스템학회:학술대회논문집
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    • 1997.10a
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    • pp.848-851
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    • 1997
  • A graphic simulation program is developed to assimilate the remote dismantling process of research nuclear reactors. This program makes extensive use of a commercial robot graphic instruction program. Firstly, a realistic graphic model of research reactors are built along with various dismantling equipments. Using the graphic instruction languages provided by IGRIP, then, a graphic process simulation program is developed that operates interactively with the user. Consequently, it is made possible for a process designer to visualize an arbitrary dismantling sequence and interactively modify the process. It is expected that the developed system will be utilized as an effective operator aid in both design and execution phases of remote dismantling of research reactor.

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Carbon Nanofibers with Controlled Size and Morphology Synthesized with Ni-MgO Catalyst Treated by Mechanochemical Process

  • Fangli Yuan;Ryu, Ho-Jin;Kang, Yong-Ku;Park, Soo-Jin;Lee, Jae-Rock
    • Journal of the Semiconductor & Display Technology
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    • v.3 no.1
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    • pp.9-13
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    • 2004
  • Carbon nanofibers (CNFs) with uniform diameter and controlled size were prepared from catalytic decomposition of $\textrm{C}_{2}\textrm{H}_{2}$ with Ni-MgO catalyst treated by mechanochemical (MC) process. The properties of Ni catalyst, such as size, distribution and morphology, can be governed by tuning grinding time in MC process. As a result, size and structure of CNFs can be tailored. The effect of grinding time to the as-grown CNFs was studied. CNFs with diameter from 10-70 nm were synthesized. CNFs with bundle formation sharing one tip and twisted CNFs were also synthesized with catalyst treated by MC process.

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A Study of 3-Dimension Graphic Monitoring System for Spent Fuel Dismantling Process

  • Kim, Sung-Hyun;Song, Tae-Gil;Lee, Jong-Youl;Yoon, Ji-Sup
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.73.1-73
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    • 2001
  • To utilize the uranium resources contained in the spent nuclear fuel generated from the nuclear power plants, the remote handling and dismantling technology is required. The dismantling process of the sport fuel is the most common process involved in the spent fuel recycling, the rod consolidation and the disposal processes. Since the machine used in the dismantling process are located and operated in isolated space, so called a hot cell, the reliability of machines is very important. To enhance the reliability of the process, in this research, the graphical monitoring system is developed for the fuel dismantling process. The graphic model of each machine is composed of many parts and every parts of the graphic model are given their own kinematics. Using the kinematics and simulating the graphic model in the virtual environment, the validity of the conceptual design can be verified before ...

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A Study on Effects of Software Process Improvement for Competitive Advantage (소프트웨어 프로세스 개선 노력이 국내 SI 업체의 경쟁우위에 미치는 영향에 관한 연구)

  • 김성희;이경아;이주헌
    • Journal of Information Technology Applications and Management
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    • v.9 no.3
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    • pp.113-127
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    • 2002
  • The effort for software process improvement is lately surging its interest though it does not satisfy both developer and receiver In terms of low productivity, quality, delay and increasing cost. According to current research, software process improvement contributes to improvement of productivity, its Duality, reduction of development time and cost, and the prediction of the time limit for delivery, which means software process improvement affects competitive advantage among developers. The latest research is whether the investment for information technology substantially had effect on improvement of productivity. That is, software process improvement and maturity of software industries has influence upon economic efficiency and as a result, it plays an important role in whole industries. This research is that how does software process improvement using CMM (Capability Maturity Model) and SPICE (Software Process Improvement and Capability dEtermination) have a effect on factors of software engineering, and how does it have influence upon competitive advantage among SI firms. For this research, reusability, customizability, participation, and review & inspection are set to independent variable and process flexibility and process predictability are set to mediate Variable. Finally, competitive advantage among SI firms Is set to dependent variable. The targets for survey are laborers who work for SI firms. The result of this research is as follows: 1 ) Reusability, Customizability and participation is not rejected but review and Inspection is rejected in process flexibility which has significant level 0.05. 2) Reusability, Customizability and participation is not rejected but review and inspection Is rejected in process predictability which has significant level 0.05. 3) Process flexibility is not rejected and process predictability Is rejected in the competitive advantage of 51 industries which has significant level 0.05

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Pilot Scale Production of Poly (3-Hydroxybutyrate-co-3-hydroxy-valerate) by Fed-batch Culture of Recombinant Escherichia coli

  • Park, Jong-il;Lee, Sang-Yup;Kyungsup Shin;Lee, Woo-Gi;Park, Si-Jae;Chang, Ho-Nam;Chang, Yong-Keun
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.7 no.6
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    • pp.371-374
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    • 2002
  • Production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate)[P(3HB/V)], by fed-batch culture of recombinant Escherichia coli harboring a plasmid containing the Alcaligenes latus polyhy-droxyalkanoate (PHA) biosynthesis genes, was examined in two pilot-scale fermentors with air supply only, In a 30 L fermentor having a XLa value of 0.11 S­$^1$, the final P(3HB/V) concentration and the P(3HB/V) content obtained were 29.6 g/L and 70.1 wt%, respectively giving a productivity of 1.37 g P(3HB/V)/L-h. In a 300 L fermentor having a XLa of 0.03 S­$^1$, the P(3HB/V) concentration and the P(3HB/V) content were 20.4 g/L and 69 wt%, respectively giving a productivity of 1.06g P(3HB/V)/L-h. These results suggest that economical production of P(3HB/V) is possible by fed-batch culture of recombinant E. coli in a large-scale fermentor having low KLa value.

A DYNAMIC SIMULATION OF THE SULFURIC ACID DECOMPOSITION PROCESS IN A SULFUR-IODINE NUCLEAR HYDROGEN PRODUCTION PLANT

  • Shin, Young-Joon;Chang, Ji-Woon;Kim, Ji-Hwan;Park, Byung-Heung;Lee, Ki-Young;Lee, Won-Jae;Chang, Jong-Hwa
    • Nuclear Engineering and Technology
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    • v.41 no.6
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    • pp.831-840
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    • 2009
  • In order to evaluate the start-up behavior and to identify, through abnormal operation occurrences, the transient behaviors of the Sulfur Iodine(SI) process, which is a nuclear hydrogen process that is coupled to a Very High Temperature Gas Cooled Reactor (VHTR) through an Intermediate Heat Exchanger (IHX), a dynamic simulation of the process is necessary. Perturbation of the flow rate or temperature in the inlet streams may result in various transient states. An understanding of the dynamic behavior due to these factors is able to support the conceptual design of the secondary helium loop system associated with a hydrogen production plant. Based on the mass and energy balance sheets of an electrodialysis-embedded SI process equivalent to a 200 $MW_{th}$ VHTR and a considerable thermal pathway between the SI process and the VHTR system, a dynamic simulation of the SI process was carried out for a sulfuric acid decomposition process (Second Section) that is composed of a sulfuric acid vaporizer, a sulfuric acid decomposer, and a sulfur trioxide decomposer. The dynamic behaviors of these integrated reactors according to several anticipated scenarios are evaluated and the dominant and mild factors are observed. As for the results of the simulation, all the reactors in the sulfuric acid decomposition process approach a steady state at the same time. Temperature control of the inlet helium is strictly required rather than the flow rate control of the inlet helium to keep the steady state condition in the Second Section. On the other hand, it was revealed that the changes of the inlet helium operation conditions make a great impact on the performances of $SO_3$ and $H_2SO_4$ decomposers, but no effect on the performance of the $H_2SO_4$ vaporizer.

Use of Nisin as an Aid in Reduction of Thermal Process of Bottled Sikhae (Rice Beverage)

  • Yoo, Jin-Young;Kwon, Dong-Jin;Park, Jong-Hyun;Koo, Young-Jo
    • Journal of Microbiology and Biotechnology
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    • v.4 no.2
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    • pp.141-145
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    • 1994
  • Conventional commercial thermal process for preparing Sikhae (Rice beverage) in a hermetically sealed container was evaluated to solve the nutritional deterioration and organoleptic inferiority problem caused by severe heat treatment. A milder thermal process with an aid of Nisin, a GRAS-grade, selectively germicidal compound, was introduced to destroy the putrefactive microorganisms. In this experiment, hot-filling method with Nisin, and thermal processing (at 110$^{\circ}C$ for 15 minutes with Nisin, at 121$^{\circ}C$ for 25 minutes without Nisin) were compared. The quality of Sikhae could be enhanced and over 90% of the thermal process could be conserved by this process in terms of sterilizing value without quality deterioration when processing the bottled Sikhae at 110$^{\circ}$ for 15 minutes $\{(F^{10}{_{121})_{process}=1.54\}$.

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Waiting Times in Polling Systems with Markov-Modulated Poisson Process Arrival

  • Kim, D. W.;W. Ryu;K. P. Jun;Park, B. U.;H. D. Bae
    • Journal of the Korean Statistical Society
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    • v.26 no.3
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    • pp.355-363
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    • 1997
  • In queueing theory, polling systems have been widely studied as a way of serving several stations in cyclic order. In this paper we consider Markov-modulated Poisson process which is useful for approximating a superposition of heterogeneous arrivals. We derive the mean waiting time of each station in a polling system where the arrival process is modeled by a Markov-modulated Poisson process.

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