• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.257.2-257.2
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• 2015

In this paper, we report on the 10.33% efficient thin film/bulk tandem solar cells with the top cell made of amorphous silicon thin film and p-type bulk crystalline silicon bottom cell. The tunneling junction layers were used the doped nanocrystalline Si layers. It has to allow an ohmic and low resistive connection. For player and n-layer, crystalline volume fraction is ~86%, ~88% and dark conductivity is $3.28{\times}10-2S/cm$, $3.03{\times}10-1S/cm$, respectively. Optimization of the tunneling junction results in fill factor of 66.16 % and open circuit voltage of 1.39 V. The open circuit voltage was closed to the sum of those of the sub-cells. This tandem structure could enable the effective development of a new concept of high-efficiency and low cost cells.

• Journal of the Korean Mathematical Society
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• v.33 no.3
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• pp.625-639
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• 1996

A convex $RP^n$-structure on a smooth anifold M is a representation of M as a quotient of a convex domain $\Omega \subset RP^n$ by a discrete group $\Gamma$ of collineations of $RP^n$ acting properly on $\Omega$. When M is a closed surface of genus g > 1, then the equivalence classes of such structures form a moduli space $B(M)$ homeomorphic to an open cell of dimension 16(g-1) (Goldman [2]). This cell contains the Teichmuller space $T(M)$ of M and it is of interest to know what of the rich geometric structure extends to $B(M)$. In [3], a symplectic structure on $B(M)$ is defined, which extends the symplectic structure on $T(M)$ defined by the Weil-Petersson Kahler form.

• Journal of Chest Surgery
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• v.25 no.10
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• pp.1102-1106
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• 1992

A 66-year-old male patient was admitted due to chest pain and dyspnea of 1 year duration, He had history of treatment for tuberculosis and pleurisy, about 40 years ago. At another hospital the patient underwnt closed thoracostomy drainage for six months, and thereafter the symptom gradually aggrevated. Under the diagnosis of chronic tuberculous empyema, decortication was performed. The peel attached to the posterolateral aspect of chest wall, there was an area of soft tissues with pale-brown discoloration, extending to intercostal muscles, but sparing overlying muscles. The biopsy specimen of the lesion was pathologically diagnosed as diffuse, large T-cell non-Hodgkin`s lymphoma. A review of the literature showed that malignant lymphoma of this type have been reported exclusively from Japan but never from other countries including Korea. After 1 year of followup period, the patient is well and stable.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.705-708
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• 2003

To observe a hydrated biological specimen, an environmental chamber was necessary to keep the specimen in a wet state under vacuum surroundings. The specimen holder is as follows designed consequently. The specimen holder consisted of two Si wafers, the centers of which were Si$_3$N$_4$(100nm thickness) windows of a 0.3mm square. The windows were made by a photo-lithographic method. The transmission of a window at 400eV is about 70%. A hydrated biological specimen was put between the two windows. When the chamber was closed, two wafers were contact at the metal mesh by the pressure of O-rings, and the specimen holder moved by the three micrometers.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.5
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• pp.241-246
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• 2015

Cellular foamed insulation such as polyurethane foam ages and degrades the thermal conductivity. Aging of foam is a result from the diffusion of gases, initially consisting of $CO_2$ but eventually replaced by air from the environment. The variation of the cell gas content with time is primarily influenced by the increase of thermal conductivity of the cellular foam. The weight of foam also changes as the gas diffuses and exchanges. In this study, a weight measurement method has been proposed to evaluate the effective diffusion coefficients of $CO_2$ and Air, $D_{CO2}=7.08504E-11$ and $D_{air}=4.86086E-12$, respectively and are compared with the gas analysis method.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.10
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• pp.2646-2653
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• 1993

A rotational torque calibration system is developed to measure rotational torque of power generating systems and to calibrate non-contact rotational torque measurement systems. The maximum capacity of the developed system is 4.5 N-m. It is composed of a DC motor, a DC generator, a control system, a master torque cell, a slip ling/brush set, supporters, a bed etc. The control system is characterized by the closed-loop control with differential intergrator. Rotational torque measurement test and unit response test are conducted to estimate the accuracy of the developed system. It is found that system maintain high consistency and accuracy with the maximum error of 0.25%, Therefore the developed system can be used to measure the rotational torque of power generating systems and to calibrate non-contact rotational torque measurement systems.

• ETRI Journal
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• v.19 no.3
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• pp.98-115
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• 1997

The architecture of the CDMA mobile system (CMS) is developed based on three function groups - service resource, service control, and service management groups. In this paper, the CMS architecture is discussed from the point of view of implementing these functions. The variable length packets are used for transmission. The synchronization clock signals are derived form the GPS receiver. The open loop and closed loop techniques are used for the power control. The internationally accepted signaling and network protocols are employed. The call control for the primary services in designed to provide efficient mobile telecommunication services. The softer handoff is implemented in one card. The mobile assisted handoff and the network assisted handoff are employed in the soft and hard handoffs. The authentication is based on the secret data which includes random numbers. The management functions, which include the location management, resource management, cell boundary management and OAM management, are implemented to warrant the system efficiency, maximum capacity and high reliability. The architecture ensures that the CMS is flexible and expandable to provide subscribers with economic and efficient system configuration. The dynamic power control, adaptive channel allocation. and dynamic cell boundary management are recommended for future work.

• Archives of Craniofacial Surgery
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• v.15 no.1
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• pp.32-35
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• 2014

Sebaceous carcinoma is a rare malignant tumor differentiated from the adnexal epithelium of sebaceous glands and forms less than 1% of all cutaneous malignancies. We present a case of a 93-year-old woman with a rapidly growing mass on the right cheek. Initial histiopathologic finding was basal cell carcinoma. The mass was widely excised and superficial parotidectomy was performed while preserving the facial nerve branches. The resulting defect was covered with a transposition flap from the ipsilateral posterior auricular area and the donor site was closed primarily. However, histopathologic examination of the excised mass showed a poorly differentiated sebaceous carcinoma with a clear resection margin. The diagnosis of sebaceous carcinoma can be difficult to make at initial presentation. This report describes a rare case of a rapidly growing extraocular sebaceous carcinoma, which resulted in a good treatment outcome, and provides a review of relevant literature.

• KSBB Journal
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• v.16 no.4
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• pp.356-359
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• 2001

The ability of Pseudomonas putida to degrade toluene was studied in toluene-containing vials. The strain grows anaerobically in toluene as a sole source of carbon. When the initial toluene concentrations injected in the vial are varied, the changes of headspace toluene concentration and cell density are observed. We set a model for this vial and simulated the vial reactor using Matlab. With a variation of model parameters, simulated results were compared with the experiment.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.2
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• pp.383-388
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• 2011

In this paper, we consider Hammerstein-Wiener nonlinear model for solid oxide fuel cell (SOFC). A nonlinear model predictive control (MPC) is proposed to trace the constant stack terminal power by Hydrogen flow as control input. After the stability of the closed-loop system with static output feedback controller is analysed by Lyapunov method, a nonlinear model predictive control based on the Hammerstein-Wiener model is developed to control the stack terminal power of the SOFC system. Simulation results verify the effectiveness of the proposed control method based on the Hammerstein-Wiener model for SOFC system.