• Title/Summary/Keyword: Open Cell

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Performance of the Small PEMFC according to Cathode (Cathode에 따른 소형 PEM 연료전지의 성능 변화)

  • Lee, Se-Won;Lee, Kang-In;Park, Min-Soo;Chu, Chong-Nam
    • Transactions of the Korean hydrogen and new energy society
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    • v.19 no.4
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    • pp.283-290
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    • 2008
  • In this paper, experiments with an air-breathing proton exchange membrane fuel cell (PEMFC) for mobile devices were carried out according to cathode conditions. These conditions are defined by the cathode flow field plate type (the channel type, the open type) and the cathode surface direction. Single-cell and 6-cell stack were used in the experiments. The experimental results showed that the open-type cathode flow field plate gave a better performance than the small channel type. In the experiments related to the direction of the slits on the cathode flow field plate, the horizontal slit cell was better than the vertical one. With respect to the cathode surface direction, when the cathode surface is placed in the direction normal to the ground, the PEMFC generated more stable power in the mass transport loss region. Since stable power in the mass transport region is closely related to the air supply, computational fluid dynamics (CFD) analysis for air-breathing PEMFC of different cathode surface directions was performed.

CFD CODE DEVELOPMENT FOR THE PREDICTION OF THE SHIP RESISTANCE USING OPEN SOURCE LIBRARIES (소스공개 라이브러리를 활용한 선박 저항계산 CFD 코드 개발)

  • Park, Sun-Ho;Park, Se-Wan;Rhee, Shin-Hyung;Lee, Sang-Bong;Choi, Jung-Eun;Kang, Seon-Hyung
    • Journal of computational fluids engineering
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    • v.17 no.2
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    • pp.21-27
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    • 2012
  • Reynolds-averaged Navier-Stokes equations solver based on a pressure-based cell-centered finite volume method was developed using OpenFOAM libraries, which was an open source and providing computational continuum mechanics libraries. For the reasonable development of the turbulent boundary layer on the bow of the ship, specified library was developed. Grid sensitivities, such as skewness and aspect ratio of a cell, were tested for the solution convergence. Pressure, turbulent kinetic energy, turbulent dissipation rate contours on the ship surface computed by the developed CFD code were compared with those computed by the commercial CFD code, Fluent.

Time-optimal multistage controllers from the theory of dynamical cell-to-cell mappings

  • Yoon, Joong-Sun
    • 제어로봇시스템학회:학술대회논문집
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    • 1989.10a
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    • pp.118-123
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    • 1989
  • This work deals with fast-to-compute global control laws for time-optimal motion of strongly nonlinear dynamic systems like resolute robots. the theory of cell-to-cell mappings for dynamical systems offer the possibility of doing the vast majority of the control law computation offline in case of time optimization with constrained inputs. These cells result from a coarse discretization of likely swaths of state space into a set of nonuniform, contiguous volumes of relatively simple shapes. Once the cells have been designed, the bang-bang schedules for the inputs are determined for all likely starting cells and terminating cells. the resulting control law is an open-loop optimal control law with feedback monitoring and correction.

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Annealing Effect on the Electrical Characteristics for Oxide Semiconductor ITO_{(n)}/Si_{(p)}$ Solar Cell (산화물 반도체 ITO_{(n)}/Si_{(p)}$ 태양전지의 전기적 특성에 미치는 열처리 효과)

  • 김용운
    • Journal of the Korean Society of Safety
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    • v.18 no.3
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    • pp.64-68
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    • 2003
  • ITO_{(n)}/Si_{(p)}$ solar cell is fabricated by vaccum deposition method under the resistance heating with substrate temperature kept about 200[$^{\circ}C$] and than their properties are investigated. The maximum output of fabricated solar cell is obtained when the composition of the thin film is consisted of indium oxide 91[mole %] and tin oxide 9(mole %). The solar cell electrical charateristics can be improved by annealing but are deteriorated at temperature above 600[$^{\circ}C$] for longer than 15[min].

Behavior of Walls of Open-cell Caissons Using Filler under Abnormally High Waves (고파랑 대비 채움재를 이용한 오픈 셀 케이슨의 전단 벽체 거동 분석)

  • Seo, Jihye;Won, Deokhee;Park, Woo-Sun
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.29 no.2
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    • pp.83-91
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    • 2017
  • In order to cope with the abnormally high waves during the storm surge due to climate change, various methods have been proposed for interlocking adjacent caissons to enhance stability of harbor structures. Among the methods, it was studied the method based on an open-cell caisson having reduction effect increasing the cohesion with adjunction caissons by filling materials such as crushed rocks in an inter-cell formed by two facing open-cells which consist of transverse walls. It is necessary to investigate the shear behaviors of an inter-cell to secure the stability using calculating shear forces on inter-cell under oblique wave loadings. It was analyzed the shear force share ratio with the length of internal and external wall and the number of internal walls. Numerical results show that 60~70% of the shear load is transmitted to adjacent caisson through the internal walls, more than 30% is through the external wall. It was applicable in the assumption that filling materials was uniformly distributed in inter-cells, and further studies were worth consideration on other conditions under construction.

Effect of Laser Ablation on Rear Passivation Stack for N-type Bifacial Solar Cell Application (N형 양면 수광 태양전지를 위한 레이저 공정의 후면 패시베이션 적층 구조 영향성)

  • Kim, Kiryun;Chang, Hyo Sik
    • Korean Journal of Materials Research
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    • v.30 no.5
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    • pp.262-266
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    • 2020
  • In this paper, we investigated the effect of the passivation stack with Al2O3, hydrogenated silicon nitride (SiNx:H) stack and Al2O3, silicon oxynitride (SiONx) stack in the n type bifacial solar cell on monocrystalline silicon. SiNx:H and SiONx films were deposited by plasma enhanced chemical vapor deposition on the Al2O3 thin film deposited by thermal atomic layer deposition. We focus on passivation properties of the two stack structure after laser ablation process in order to improve bifaciality of the cell. Our results showed SiNx:H with Al2O3 stack is 10 mV higher in implied open circuit voltage and 60 ㎲ higher in minority carrier lifetime than SiONx with Al2O3 stack at Ni silicide formation temperature for 1.8% open area ratio. This can be explained by hydrogen passivation at the Al2O3/Si interface and Al2O3 layer of laser damaged area during annealing.

Immunohistochemical Studv on the Gastrin, Somatostatin and Serotonin Cells in the Gastric and Small Intestinal Mucosa of Rat during Development (발생기 흰쥐 위와 소장점막의 gastrin, somatostatin 및 serotonin세포에 대한 면역조직화학적연구)

  • 최병태;조운복
    • The Korean Journal of Zoology
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    • v.37 no.4
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    • pp.478-487
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    • 1994
  • The developmental changes of three enteroendocrine cells, i.e. gastrln, somatostatin and serotonin, of gastric and small intestinal mucosa in pre- and postnatal rat were examined by peroxidase-antiperoxidase (PAP) method. In the course of development, gastrin cells were obsenred in the pyloric gland region and the whole part of small intestine, while somstostatin and serotonin cells in the whole gastric gland region and small intestine. More entroendocrine cells were detected in the pyloric gland region and duodenum than in the other portion. In the stomach, gastrin, somatostatin and serotonin ceils were first obsenred in the pyloric Bland region on 17, 19 and 19 days of gestation respectively. The small intestinal gastrin and serotonin cells were first appeared in the duodenum and iriunum on 17 and 15 days of gestation respectively, and somatostBtin cells in duodenum on 17 days of gestation. The number of cells examined from the stomach were increased from fetal to weanling period and showed a decrease during adult period: the notable increase was shown at the end of suckling period or at early weanling period. The cells of the small intestine increased from fetal to suckling period, especially, these cells markedly increased at the end of fetal period or at early suckling period, and decreased from weanling period. The shape of these cells was oval or fusiform during fetal period. In the stomach, most of gastrin cells turned out to be oval and open-type from suckling period, while the remaining two tripes of cells were oval and open- or closed-type. In the small intestine, 311%Ves of cells examined were changed to fusiform and open-type from the end of fetal period. Three types of cell were distributed over the stratified epithelium on 15 and 17 days of gestation. In the stomach, these cells were distributed lower gastric pit and gland from the following fetal period, and were detected mainly on the upper part of gland from suckling period, and then obsenred on the whole part of gland. In the small intestine, most of cells distributed over only between epithelium of villi on 19 days of gestation, increased in number on the crypt from following fetal period, and also observed abundantly in the crypt at adult period.

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A Solar Energy Harvesting Circuit with Low-Cost MPPT Control for Low Duty-Cycled Sensor Nodes. (낮은 듀티 동작의 센서 노드를 위한 저비용 MPPT 제어기능을 갖는 빛에너지 하베스팅 회로)

  • Yoon, Eun-Jung;Yang, Min-Jae;Yu, Chong-Gun
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2015.10a
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    • pp.397-400
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    • 2015
  • In this paper a solar energy harvesting system with low-cost MPPT control for low duty-cycled sensor nodes is proposed. The targeted applications are environment, structure monitoring sensor nodes that are not required successively to operate, and MPPT(Maximum Power point Tracking) control using simple circuits is low-cost differently than existing MPPT control. The proposed MPPT control is implemented using linear relationship between the open-circuit voltage of a solar cell. The designed MPPT circuit traces the maximum power point by sampling periodically the open circuit voltage of the solar cell and delivers the maximum available power to the load. The proposed circuit is designed in 0.35um CMOS process. The designed chip area is $975um{\times}1025um$ including pads. Measured results show that the designed system can track the MPP voltage by sampling periodically the open circuit voltage of solar cell.

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Metallization of Buired contact Solar cell (BCSC(Buired contact Solar cell)의 전극형성)

  • 김동섭;조영현;이수홍
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1995.05a
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    • pp.145-149
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    • 1995
  • The metallization is the key to determining cell costs, call performance, and cell and system reliabiltiy. The Burled Contact Solar Cell (BCSC) was specifical1y desinged to be compatible tilth low cost, mass production techniques and avoid the conventional metallization problem. By using electroless plating trchniqeu, we performed this metallization inexpensively and reliabley, This paper presents the details of the optimization procedure of metallization schemes on laser grooved cell surface Commercially available Ni ,Cu, and Ag plating solutions were applied for the cell metallization. The application of those solutions on the buried contact front metalization has resulted in an cell efficiency of 18.5% The cell parameters are an open circuit voltage of 651 mV, short circuit current density of 38.6 mA/$\textrm{cm}^2$, and fill factor of 73.5%.

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OpenVolMesh: Generic and Efficient Data Structure for 3D Volumetric Meshes (OpenVolMesh: 삼차원 볼륨 기반의 메쉬 표현을 위한 범용적이고 효과적인 자료 구조)

  • Kim, Jun-Ho;Seo, Jin-Seok;Oh, Sei-Woong
    • The Journal of the Korea Contents Association
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    • v.8 no.7
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    • pp.85-92
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    • 2008
  • Meshes are the most appropriate data structures for representing 3D geometries. Surface meshes have been frequently used for representing 3D geometries, which only samples data on the surfaces of the given 3D geometries. Thanks to the improvements of computing powers, it is required to develop more complicated contents which utilize the volumetric information of 3D geometries. In this paper, we introduce a novel volumetric mesh libraries based on the half-face data structure, called OpenVolMesh, and describe its designs and implementations. The OpenVolMesh extends the OpenMesh, which is one of the most famous mesh libraries, by supporting volumetric meshes. The OpenVolMesh provides the generic programming, dynamic allocations of primitive properties, efficient array-based data structures, and source-level compatibility with OpenMesh. We show the usefulness of the OpenVolMesh in the developments of 3D volumetric contents with prototypic implementations such as volumetric mesh smoothing and CW-cell decompositions.