• Applied Chemistry for Engineering
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• v.35 no.1
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• pp.61-65
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• 2024

The effectiveness of CuSCN as a hole injection layer in large-area organic light-emitting diodes, organic solar cells, and thin-film transistors has been well demonstrated. Therefore, in this study, the surface, optical, and electrical analyses of CuSCN were carried out according to the solution process conditions in order to propose optimized film conditions. Various CuSCN solution concentrations were prepared to determine the film surface characteristics and to determine whether the film surface affects the electrical performance of the device. When the CuSCN solution concentration was low, the CuSCN film was not formed and coated in the form of islands, and when the solution concentration was increased, the CuSCN film was formed uniformly, which contributed to improving the conductivity of the device. In addition, a hole-only device was fabricated to demonstrate the role of CuSCN as a hole transport layer.

• Journal of Communications and Networks
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• v.16 no.5
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• pp.568-577
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• 2014

We consider a mobile content delivery network (mCDN) in which special mobile devices designated as caching servers (caching-server device: CSD) can provide mobile stations with popular contents on demand via device-to-device (D2D) communication links. On the assumption that mobile CSD's are randomly distributed by a Poisson point process (PPP), an optimization problem is formulated to determine the probability of storing the individual content in each server in a manner that minimizes the average caching failure rate. Further, we present a low-complexity search algorithm, optimum dual-solution searching algorithm (ODSA), for solving this optimization problem. We demonstrate that the proposed ODSA takes fewer iterations, on the order of O(log N) searches, for caching N contents in the system to find the optimal solution, as compared to the number of iterations in the conventional subgradient method, with an acceptable accuracy in practice. Furthermore, we identify the important characteristics of the optimal caching policies in the mobile environment that would serve as a useful aid in designing the mCDN.

• Journal of Pharmaceutical Investigation
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• v.11 no.3
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• pp.14-20
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• 1981

One of the major objectives in the developments of a progesterone I.U.D. is to prepare devices which release drug at a constant rate for extended periods. A constant release rate is achived by maintaining drug concentration at a constant valve via the introduction of rate limiting membrane to solute diffusion at the surface of the devices. In this study, progesterone dispersed at monolithic device were prepared from polyhydroxy ethyl methacrylate. Constant release rate were obtained with device which were soaked in on ethanol-hexan solution. The release rate was dependant upon the concentration of the ethanolic solution in the soaking solution. This devices offer significant potential for futher development of hydrogel in the intrauterine contraception device for controlled release of progesterone.

• Proceedings of the Korean Statistical Society Conference
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• 2005.05a
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• pp.197-201
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• 2005

In this article, we will compare the performance of the mean control chart, the median control chart, the transformed mean control chart, the transformed median control chart, and the precedence control chart by simulation study. For control charts with transformed data, Yeo-Johnson transformation is used. Under the in-control condition, ARL's in all control charts coincide with the designed ARL in the normal distribution, but in the other distributions, only the precedence control chart provides the in-control ARL as designed. Under the out-of-control condition, the mean control chart is preferred in the normal distribution and the median control chart is preferred in the heavy-tailed distribution and the precedence control chart outperforms in the short-tailed distribution.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.537-539
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• 2009

We report the improvement in adhesion of IZO thin films through oxygen ($O_2$) plasma treatment of organic polymer film. In conclusion, the $O_2$ plasma treatment of an organic polymer film was accomplished with improving ca. 1.8 times in adhesion than that of the only general etch treatment on the same organic polymer film.

• Current Photovoltaic Research
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• v.3 no.4
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• pp.116-120
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• 2015

A hybrid transparent conducting layer was applied for Si photodetector. To realize the hybrid transparent conducting layer, a 200 nm-thick ITO layer was deposited onto a Si substrate, following by a solution-processed AgNWs-coating on the ITO. The hybrid transparent conducting layer showed an excellent low electric resistance of $15.9{\Box}/{\Omega}$ with a high optical transparency of 86.89%. Due to these optical and electrical benefits, the hybrid transparent conductor-embedding Si diode provides an extremely high rectifying ratio of 3386. Under light-illumination, the hybrid transparent conductor device provides extremely high photoresponses for broad wavelengths. This implies that a functional design for hybrid transparent conductor is crucial for photoelectric devices and applications.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.26.1-26.1
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• 2009

A simple route of external mechanical force is presented for enhancing the electrical properties of polymer nanocomposite consisted of nanowires. By dispersing ZnO nanowires in polymer solution and drop casting on substrates, nanocomposite transistors containing ZnO nanowires are successfully fabricated. Even though the ZnO nanowires density is properly controlled for device fabrication, as-cast device doesn't show any detectable currents, because nanowires are separated far from each other with the insulating polymer matrix intervening between them. Compared to the device pressed at 300 kPa, the device pressed at 600 kPa currents increased by 50times showing the linear behavior against drain voltage and exhibits promising electrical properties, which operates in the depletion mode with higher mobility and on-current. Such an improved device performance would be realized by the contacts improvement and the increase of the number of electrical path induced by external force. This approach provides a viable solution for serious contact resistance problem of nanocomposite materials and promises for future manufacturing of high-performance devices.

• Advances in aircraft and spacecraft science
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• v.2 no.3
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• pp.329-343
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• 2015

This study aimed to observe the effect of a novel concept (referred to as the flap extension) implemented on the leading edge of the flap of a three element high lift device. The high lift device, consisting of a flap, main element and slat is designed around an Airbus research profile for sufficient take off and landing performance of a large commercial aircraft. The concept is realised on the profile and numerically optimised to achieve an optimum geometry. Two different optimisation approaches based on Genetic Algorithm optimisations are used: a zero order approach which makes simplifying assumptions to achieve an optimised solution: as well as a direct approach which employs an optimisation in ANSYS DesignXplorer using RANS calculations. Both methods converge to different optimised solutions due to simplifying assumptions. The solution to the zero order optimisation showed a decreased stall angle and decreased maximum lift coefficient against angle of attack due to early stall onset at the flap. The DesignXplorer optimised solution matched that of the baseline solution very closely. The concept was seen to increase lift locally at the flap for both optimisation methods.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.7
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• pp.326-331
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• 2005

We obtain analytical expressions the magnetic field of ferrites for DC magnetron sputtering device, which has been widely used for vacuum thin film deposition, and suggested the equation on maximum radius of the magnetic field by analytic solution. Also, the analytic results are compared with some calculations using magnetization elements of right-angled hexahedron.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.791-793
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• 2009

We have developed novel small molecular materials for solution phosphorescent OLEDs having multilayered device structures. These novel materials are applied as an interlayer which is between a buffer layer (or hole injection layer) and an emitting layer to improve the luminance efficiency of solution green phosphorescent OLEDs. In order to form stable double layers by spincoating process, we take the advantage of solubility differences of interlayer materials and emitting materials. Using CIM3 as an interlayer, we have attained the best luminance efficiency, 36 cd/A at a given constant of 2000cd/$m^2$ in the structure of ITO/PEDOT:PSS/CIM3/CIM6:Ir(mppy)$_3$/BAlq/Alq$_3$/LiF/Al.