• Title/Summary/Keyword: working mechanism

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Development of the Efficiency-Evaluation Model for the Mechanism of CO2 Sequestration in a Deep Saline Aquifer (심부 대염수층 CO2 격리 메커니즘에 관한 효율성 평가 모델 개발)

  • Kim, Jung-Gyun;Lee, Young-Soo;Lee, Jeong-Hwan
    • Journal of the Korean Institute of Gas
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    • v.16 no.6
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    • pp.55-66
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    • 2012
  • The practical way to minimize the greenhouse gas is to reduce the emission of carbon dioxide. For this reason, CCS(Carbon Capture and Storage) technology, which could reduce carbon dioxide emission, has risen as a realistic alternative in recent years. In addition, the researcher is recently working into ways of applying CCS technologies with deep saline aquifer. In this study, the evaluation model on the feasibility of $CO_2$ sequestration in the deep saline aquifer using ANN(Artificial Neural Network) was developed. In order to develop the efficiency-evaluation model, basic model was created in the deep saline aquifer and sensitivity analysis was performed for the aquifer characteristics by utilizing the commercial simulator of GEM. Based on the sensitivity analysis, the factors and ranges affecting $CO_2$ sequestration in the deep saline aquifer were chosen. The result from ANN training scenario were confirmed $CO_2$ sequestration by solubility trapping and residual trapping mechanism. The result from ANN model evaluation indicated there is the increase of correlation coefficient up to 0.99. It has been confirmed that the developed model can be utilized in feasibility of $CO_2$ sequestration at deep saline aquifer.

Altered Expression of RANKL/OPG after Alendronate Administration in the Developing Teeth of Postnatal Rats

  • Kim, Min-Ju;Jun, Yun-Jeong;Yu, Hong-Il;Yang, So-Yeong;Oh, Won-Man;Kim, Sun-Hun;Kim, Min-Seok
    • International Journal of Oral Biology
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    • v.36 no.1
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    • pp.37-42
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    • 2011
  • The working mechanism of bisphosphonate on bone cells is unclear despite its powerful inhibitory activity on bone resorption. The differentiation and activation of osteoclasts are essential for bone resorption and are controlled by the stimulatory RANKL and inhibitory OPG molecules. Teeth exhibit a range of movement patterns during their eruption to establish their form and function, which inevitably accompanies peripheral bone resorption. Hence, the mandible, which contains the teeth during their eruption processes, is a good model for revealing the inhibitory mechanism of bisphosphonate upon bone resorption. In the present study, RANKL and OPG expression were examined immunohistochemically in the mandible of rats with developing teeth after alendronate administration (2.5 mg/kg). The preeruptive mandibular first molars at postnatal days 3 to 10 showed the developing stages from bell to crown. No morphological changes in tooth formation were observed after alendronate administration. The number of osteoclasts in the alveolar bone around the developing teeth decreased markedly at postnatal days 3, 7 and 10 compared with the control group. RANKL induced strong positive immunohistochemical reactions in the dental follicles and stromal cells around the mandibular first molar. In particular, many osteoclasts with strongly positive reactions to RANKL appeared above the developing mandibular first molars at postnatal days 3 and 10. Immunohistochemical reactions with RANKL after alendronate administration were weaker than the control groups. However, the immunohistochemical reactivity to OPG was stronger after alendronate administration, at postnatal days 3 and 10. These results suggest that alendronate may decrease bone resorption by regulating the RANKL/OPG pathway in the process of osteoclast formation, resulting in a delay in tooth eruption.

Study on the Anchovy Boat Seine-IV An Experiment to Mechanize the Hauling Operation of Bag Net (기선권현 강의 연구 -IV)

  • 이병기
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.15 no.2
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    • pp.95-100
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    • 1979
  • In fishing with the anchovy boat seine, it is required to haul up the bag net without injuring anchovy body. Not to injure anchovy body, the bag net is operated with 30 to 34 crews in the traditional method. With a view point of decreasing crews, the authors tried to operate the bag net with side drum winch and derrick boom. Side drum winch was installed beside the engine casing and it was operated by the main engine through the belt, pulley and bevel gear. The derrick boom, 7 meters long, was installed above the working deck which is located in the stern of the common boat seiner. Three single blocks are attached to the boom, each 2 meters apart from the top. A hook was attached to the free end of the block line for hooking up the bolch line which attached inside the bag net especially prepared for the purpose. The hauling end of the block line was induced to the side drum winch for hauling up the bag net. By using this mechanism, the bag net was hauled up with peeling the bag net just like in the traditional method. So the following results are found. (1) No injury of anchovy body was found in the process of hauling up. (2) The bag net can be operated by mere 14 crews. (3) Duration, spent in hauling up the bag net, was almost the same when the catch are a little amount, and less duration was needed by the experimented method than the traditional one when the catch are a large amount. the bag net. By using this mechanism, the bag net was hauled up with peeling the bag net just like in the traditional method. So the following results are found. (1) No injury of anchovy body was found in the process of hauling up. (2) The bag net can be operated by mere 14 crews. (3) Duration, spent in hauling up the bag net, was almost the same when the catch are a little amount, and less duration was needed by the experimented method than the traditional one when the catch are a large amount.

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6TALK : Implementation of NAT-PT/SIIT and enhanced ALG

  • 이주철;호용근;신명기;김형준
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2002.11a
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    • pp.701-705
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    • 2002
  • This paper describes implementation of IPv6-IPv4 transition toolbox named as 6TALK(IPv6 TrAansLator of Krv6) and some scenarios using 6TALK which enables IPv6 island to connect other IPv6 island or IPv4 island seamlessly. 6TALK implements some transition mechanisms suggested in NGTrans Working Group of IETF. Those mechanisms are composed of basic mechanism, tunneling, and applied mechanism such as DSTM. 6TALK provides functions which enable IPv6 network at the edge of existing network to communicate with IPv4 network by using these transition mechanisms. As major transition mechanisms in 6TALK we adopt NAT-PT/SIIT and DSTM/DSTM options and as implementation environment we use Linux Kernel 2.4.18 and Netfilter framework. Software modules implemented in Linux kernel was ported to hardware box using Motorola MPC 8260 processor. The transition mechanisms used in 6TALK are the ones predicted to be used in initial transition step to IPv6.

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THE EFFECT OF THE SUPERSATURATED SOLUTIONS CONTAINING HIGH CONCENTRATIONS OF FLUORIDE ON SEEDED CRYSTAL GROWTH (고농도의 불소를 포함하는 과포화용액이 apatitic crystal growth에 미치는 영향)

  • Kwun, Jung-Won;Kum, Kee-Yeon;Lee, Seung-Jong;Jung, Il-Young;Lee, Chan-Young
    • Restorative Dentistry and Endodontics
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    • v.24 no.2
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    • pp.330-336
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    • 1999
  • In biological systems, the mineral that forms hard tissue is of an apatitic nature, and hydroxyapatite($Ca_5OH(PO_4)_3$: HA) is generally considered as the prototype for such a mineral. Thus, the precipitation of HA, having biological implications, has been the subject of several investigations. Crystal growth studies using HA seeds in supersaturated solutions have enhanced our understanding of the process and mechanism involved in seeded crystal growth. From these studies, it has become apparent that the precipitation rate of HA onto the seed crystals depends on the various conditions, especially on the additives. The relation between the supersaturated solution containing fluoride and the process of HA crystal growth enhances the understanding of mechanism of HA crystal growth. Until recently, the studies have been on the crystal growth of enamel minerals and synthetic HA seeds in the supersaturated solution containing 1~2 ppm fluoride. The purpose of the present investigation is to study the effect that fluoride of high concentration has on the crystal growth kinetics of HA. In order to produce the composition found in the secretory enamel fluid, experimental solutions of 1mM Ca, 3mM P, and 100mM Tris as background electrolyte were used. Then this experimental solutions were added to 0, 2, 4, 6, 8, 10 ppm fluoride. The effect of fluoride at high concentrations on the precipitation was examined in a bench-top crystal growth model adopting a miniaturized reaction column. Chemical analysis was employed for characterization of working solutions before and after the experimentation. Remarkable findings were : 1) the amount of crystal growth was gradually accelerated as the fluoride concentration increased until 6 ppm, but decreased in 8 and 10 ppm fluoride; 2) the amount of fluoride ion consumed in crystal formation was constant despite the increase in fluoride concentration.

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Electrical mechanism analysis of $Al_2O_3$ doped zinc oxide thin films deposited by rotating cylindrical DC magnetron sputtering (원통형 타겟 형태의 DC 마그네트론 스퍼터링을 이용한 산화 아연 박막의 전기적 기제에 대한 분석)

  • Jang, Juyeon;Park, Hyeongsik;Ahn, Sihyun;Jo, Jaehyun;Jang, Kyungsoo;Yi, Junsin
    • 한국신재생에너지학회:학술대회논문집
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    • 2010.11a
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    • pp.55.1-55.1
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    • 2010
  • Cost efficient and large area deposition of superior quality $Al_2O_3$ doped zinc oxide (AZO) films is instrumental in many of its applications including solar cell fabrication due to its numerous advantages over ITO films. In this study, AZO films were prepared by a highly efficient rotating cylindrical dc magnetron sputtering system using AZO target, which has a target material utilization above 80%, on glass substrates in argon ambient. A detailed analysis on the electrical, optical and structural characteristics of AZO thin films was carried out for solar cell application. The properties of films were found to critically depend on deposition parameters such as sputtering power, substrate temperature, working pressure, and thickness of the films. A low resistivity of ${\sim}5.5{\times}10-4{\Omega}-cm$ was obtained for films deposited at 2kW, keeping the pressure and substrate temperature constant at 3 mtorr and $230^{\circ}C$ respectively, mainly due to an increase in carrier mobility and large grain size which would reduce the grain boundary scattering. The increase in carrier mobility with power can be attributed to the columnar growth of AZO film with (002) preferred orientation as revealed by XRD analysis. The AZO films showed a high transparency of>87% in the visible wavelength region irrespective of deposition conditions. Our results offers a cost-efficient AZO film deposition method which can fabricate films with significant low resistivity and high transmittance that can find application in thin-film solar cells.

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The optical properties of columnar structure according to the growth angles of ZnO thin fims (성장각도에 따른 주상구조 ZnO 박막의 광학적 특성)

  • Ko, Ki-Han;Seo, Jae-Keun;Kim, Jae-Kwang;Kang, Eun-Kyu;Park, Mun-Gi;Ju, Jin-Young;Shin, Yong-Deok;Choi, Won-Seok
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.11a
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    • pp.127-127
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    • 2009
  • The most important part of the fabrication solar cells is the anti-reflection coating when excludes the kinds of silicon substrates (crystalline, polycrystalline, or amorphous), patterns and materials of electrodes. Anti-reflection coatings reduce the reflection of sunlight and at last increase the intensity of radiation to inside of solar cells. So, we can obtain increase of solar cell efficiency about 10% using anti-reflection coating. There are many kinds of anti-reflection film for solar cell, such as SiN, $SiO_2$, a-Si, and so on. And, they have two functions, anti-reflection and passivation. However such materials could not perfectly prevent reflection. So, in this work, we investigated the anti-reflection coating with the columnar structure ZnO thin film. We synthesized columnar structure ZnO film on glass substrates. The ZnO films were synthesized using a RF magnetron sputtering system with a pure (99.95%) ZnO target at room temperature. The anti-reflection coating layer was sputtered by argon and oxygen gases. The angle of target and substrate measures 0, 20, 40, 60 degrees, the working pressure 10 mtorr and the 250 W of RF power during 40 minutes. The confirm the growth mechanism of ZnO on columnar structure, the anti-reflection coating layer was observed by field emission scanning electron microscopy (FE-SEM). The optical trends were observed by UV-vis and Elleso meter.

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A Study on the Cleaning Characteristics according to the process gas of Low-Pressure Plasma (저압 플라즈마 세정가스에 따른 세정특성 연구)

  • Koo, H.J.;Ko, K.J.;Chung, C.K.
    • Clean Technology
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    • v.7 no.3
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    • pp.203-214
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    • 2001
  • A silicon oxide cleaning characteristic and its mechanism were studied in RF plasma cleaning system with various gases such as $CHF_3$, $CF_4$, Argon, oxygen and mixing gas. The experimental parameters - working pressure (100 mTorr), RF power (300 W, 500 W), electrode distance (5cm, 8cm, 11.5cm), cleaning time (90, 180 seconds), gas flow (50 sccm) were fixed to compare cleaning efficiency by gas types. The results were as follows. First, the argon plasma is retaining only physical sputtering effect and etch rate was low. Second, the oxygen plasma showed good cleaning efficiency in electrode distace of 5cm, 300W, 180secs, but surface roughness increased. Third, $CF_4$ Plasma could get the best cleaning efficiency. Fourth, $CHF_3$ plasma could know that addition gas that can lower the CFx/F ratio need. We could not get good cleaning efficiency in case of added argon to $CHF_3$. But, we could get good cleaning efficiency in case added oxygen.

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Practical Project Behavior Management Methods for Large-scale IT Projects (대규모 IT 프로젝트를 위한 실용적 행태관리 방안)

  • Kim, Min-Seon;Song, Sung-Hwan;Kim, Yong-Sik
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.7
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    • pp.4897-4911
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    • 2015
  • Technology developments accelerate the change of the society and companies with unparalleled pace, so large scaled projects are in progress urgently. Large scaled projects deal with high technologies and massive tasks, and these need enormous labor force and costs, it is necessary to manage strategic conflicts based on human psychology and complex system theory. However, traditional management plan fails to suggest practical mechanism for successful projects. We study failure cases and key elements, leadership for projects, and suggest project management plan with psychological and behavioral economy approach by focusing on complexity and conflict structure on large scaled projects. Project behavior management plan, suggested in this study, is designed with phased strategy and practice to solve the failure of large scaled IT projects originally and preemptively. We verified the effectiveness of behavior management plan suggested by investigating experts and working groups, and stable projects are to be progressed with introducing this plan on large-scaled projects.

Study on the Development of Working Safety Device for Visually Impaired Person (시각장애인 보행안전장치 개발에 관한 연구)

  • Kim, Hyo-Gwan;Choi, Young-Gyu
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.9 no.4
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    • pp.366-372
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    • 2016
  • This paper advances the software, hardware and mechanical design that the visually impaired can recognize the position and distance of the obstacle while walking. The first software implementation is proposed a method to implement the algorithm graph for the ratio of the distance measuring ultrasonic sensors for voltage. And it was extracted by the precise distance measuring parameter values from simulation to measure the precise distance. Second hardware implementation was designed to be able to detect obstacles in a relatively simple sensor-based walking aid for the visually impaired. In addition, using the switching regulator IC of high performance it was designed to be used to boost the Li-ion battery 3.7V to 5V. The third mechanism was developed by analyzing the sensor angle and the cane angle.