• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.181-181
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• 2012

Direct synthesis of graphene using a chemical vapor deposition (CVD) has been considered a facile way to produce large-area and uniform graphene film, which is an accessible method from an application standpoint. Hence, their fundamental understanding is highly required. Unfortunately, the CVD growth mechanism of graphene on Cu remains elusive and controversial. Here, we present the evidences for two different growth modes of graphene on Cu investigated by varying carbon feedstock (C2H2 and CH4) and working pressure. The number of uniform graphene layer grown by C2H2 increased with increasing its injection time. A combined secondary ion mass spectrometry (SIMS) and X-ray diffraction (XRD) study revealed a carbon-diffused Cu layer created below surface region of Cu substrate with the expansion of Cu lattice. The graphene on Cu was grown by the diffusion and precipitation mode not by the surface adsorption mode, because similar results were observed in graphene/Ni system. The carbon-diffused Cu layer was also observed after graphene growth under high CH4 pressure. Based on various previous results and ours, we have successfully found that there are two selective growth modes for graphene on Cu substrate, and a desired mode can be chosen by tuning working pressure corresponding to the kind of carbon feedstock. We believe that this finding will shed light on high quality graphene growth and its multifaceted applications.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.1
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• pp.664-675
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• 2016

The purpose of the study was to explore the nurses' perception of flexible working and present an operational guideline for implementation. The data were collected from a survey of 532 nurses conducted from 10 February to 24 February, 2015, using simple random sampling. SPSS 21.0 was used to analyze the data. This study found that the demanding for shorter hour shifts was highest ($M=3.89{\pm}0.87$) and 242 participants (46.2%) intended to apply the shift, followed by a fixed night shift, fixed weekend shift, and 12 hour shift. The common reasons identified were the poor environment of shift work and the challenges of child care. The increased time for personal development, relaxation activity to improve the quality of life and child care was highlighted and work-life balance was noted as a positive impact of flexible working. The negative impacts of flexible working were being likely to become temporary workers. These results can help establish uniform working conditions of nurses in the future by providing a standardized operational guideline as a precondition for reasonable compensation and working environment according to a flexible working pattern.

• International Commerce and Information Review
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• v.4 no.2
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• pp.1-12
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• 2002

The purpose of this paper is to examine the scope of the application of Preliminary Draft Convention, which will be fixed as international uniform rules soon, in relation to the CISG. First, this Draft Convention will cover service contracts as well as sales contract of goods, but the license agreement will be excepted because it does not transfer the complete property. Second, this will cover the commercial contracts(sales or services) concluded by data message fully or partially. Third, this will be applied in international contract regardless of contracting states or non-contracting states. As it is very difficult to confirm the places of business of contracting parties in on-line contracts, the first criterion to confirm them is the indication by the party in each contract. This presumption may be supplemented, if they are not indicated in the contract, by the location of the equipment and technology supporting an information system used by a legal entity for the conclusion of a contract. It is essential to establish an international uniform rules as soon as possible in order to activate the international businesses with on-line basis. Thus this author hopes that this paper will contribute to the clear understanding to the scope of application of Preliminary Draft Convention for which the UNCITRAL is under working.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.3
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• pp.340-348
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• 2013

In Projection Stereolithography Apparatus (PSLA), Digital Micromirror Device (DMD) and Liquid Crystal Display (LCD) are used as a beam pattern generator. The DMD shows high resolution, but it is mostly applied in micro stereolithography due to high cost and fabricable area. In LCD, the size of pattern beam is freely controlled due to various panel sizes. The LCD, however, has some limitations such as short life time by the high power light source, non-uniform light intensity of pattern beam and low transmittance of UV-light. To solve these problems in LCD-based PSLA, a Scanbeam-SLA with LCD of 19 inches and visible LED-array is developed. In this system, the light module works like a scanner for uniform illumination. The system configuration, working principle and fabrication examples are addressed in this study.

• Journal of Powder Materials
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• v.25 no.1
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• pp.1-6
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• 2018

Uniform $TiO_2$ blocking layers (BLs) are fabricated using ultrasonic spray pyrolysis deposition (USPD) method. To improve the photovoltaic performance of dye-sensitized solar cells (DSSCs), the BL thickness is controlled by using USPD times of 0, 20, 60, and 100 min, creating $TiO_2$ BLs of 0, 40, 70, and 100 nm, respectively, in average thickness on fluorine-doped tin oxide (FTO) glass. Compared to the other samples, the DSSC containing the uniform $TiO_2$ BL of 70 nm in thickness shows a superior power conversion efficiency of $7.58{\pm}0.20%$ because of the suppression of electron recombination by the effect of the optimized thickness. The performance improvement is mainly attributed to the increased open-circuit voltage ($0.77{\pm}0.02V$) achieved by the increased Fermi energy levels of the working electrodes and the improved short-circuit current density ($15.67{\pm}0.43mA/cm^2$) by efficient electron transfer pathways. Therefore, optimized $TiO_2$ BLs fabricated by USPD may allow performance improvements in DSSCs.

• Journal of the Korean Society for Heat Treatment
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• v.31 no.2
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• pp.41-48
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• 2018

In this study, microstructural changes due to extrusion, rolling and heat treatment were studied to fabricate Al-4.0wt%Zn-1.5wt%Mg-0.9wt%Cu alloys with homogeneous microstructure suitable for metal cases of smart phones and electronic products fabricated through plastic working. After extrusion microstructure and texture were developed very differently on the surface and inside. Inside, coarse grains were formed and a strong Cube component orientation was developed. On the surface, a weak texture was developed with small grains. After 72% cold rolling the intensity of the Cube component orientation was lower, and uniform texture was developed in all the layers and the R-value was uniformly predicted. After recrystallization, the grain size difference between at the surface and the inside is smaller, when 72% rolling was performed, indicating that a uniform structure is formed. Texture develops almost randomly after recrystallization and exhibits uniform R-values at all layers.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.129-129
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• 2022

The production area of Italian ryegrass feed is gradually increasing and labor-saving technologies are being developed. If sowing and fertilization are carried out agricultural drones, working hours and labor are reduced. The purpose of this study is to suggest an appropriate seedling amount for feed production by drone spreading of Italian ryegrass in spring. In addition, we would like to review the productivity of the drone seeding machine that is being developed by Rural Development Administration(RDA) of Korea. Italian ryegrass was sown by a drone in February at the NICS located in Gyehwa-hwa, Jeollabuk-do, South Korea. In Experiment 1, 50kg/ha, 60, 70, and 80 seeding rates were sown with a horizontal spreader drone. In Experiment 2, uniform spreaders type drone and horizontal spreader type were sown with the same seeding amount and compared. The drone was sown using the AF-52 aircraft. The higher the seeding amount, the higher the emergence rate. As the seeding amount increased, the plant length increased, but the number of tillers per individual decreased. The dry matter weight of the feed was the highest at 1,326kg/10a at the seeding rate of 70kg/ha, and decreased by 20.5% at the seeding rate of 80kg/ha. The coverage ratio was the highest at 96 at the seeding rate of 70kg/ha, which was the most advantageous for spring sowing. In the comparative experiment according to the spreader type, the uniform spreader had a high emergence rate per unit area. When the uniform spreader was used, the dry matter weight of the feed was 17% higher than that of the horizontal one, and the coverage was about 5% higher.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.181.2-181.2
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• 2015

Sputtering is one of the most popular physical deposition methods due to their versatility and reproducibility. Synthesis of Cr thin films by DC magnetron sputtering using glancing angle deposition (GLAD) has been reported. Chromium thin films have been prepared at two different working pressure($2.0{\times}10-2$, 30, $3.3{\times}10-3torr$) on Si-wafer substrate using magnetron sputtering with glancing angle deposition (GLAD) technique. The thickness of Cr thin films on the substrate was adjusted about 1 mm. The electrical property was measured by four-point probe method. For the measurement of density in the films, an X-ray reflectivity (XRR) was carried out. The sheet resistance and column angle increased with the increase of glancing angle. However, nanohardness and density of Cr thin films decreased as the glancing angle increased. The measured density for the Cr thin films decreased from 6.1 to 3.8 g/cc as the glancing angle increased from $0^{\circ}$ to $90^{\circ}$ degree. The low density of Cr thin films is resulted from the isolated columnar structure of samples. The evolution of the isolated columnar structure was enhanced at the conditions of low sputter pressure and high glancing angle. This GLAD technique can be potentially applied to the synthesis of thin films requiring porous and uniform coating such as thin film catalysts or gas sensors.

• Journal of Drive and Control
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• v.16 no.4
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• pp.87-92
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• 2019

Rotary dampers are damping devices which provide high resistance to shaft rotation. Rotary dampers are being used in various areas to enable the gentle opening and closing of the rotation motion relative to home furniture, industry machinery and automotive parts. Rotary dampers can be installed directly at the rotating point of a various part and can achieve uniform, gentle movement which increases quality and value of products. And generally, the silicone fluid is used as the damping medium because of its stable viscous properties. The movement of these little decelerators can be achieved with a high viscosity of working fluid and throttles installed in the body of the rotary damper. The damping force can be achieved clockwise, anti-clockwise or in both directions according to the structure of the orifices or throttles. In this paper, the torque performances of the rotary damper containing air in the working fluid were studied. For this purpose, the torque characteristic of the rotary damper according to the variation of various operating conditions such as clearance of leakage, dimensions of groove orifice, content ratio of air, etc., were simulated with AMEsim software.

• Korean Institute of Interior Design Journal
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• v.22 no.5
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• pp.106-113
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• 2013

Since the 1960's, diverse movements that oppose the uniform design tendency of modernism appears in Italy. Especially, Gaetano Pesce, who opposed uniformity and standardization that are based on mass production system, had interests in making unique product, not an identical product, while accepting modern production technology. Therefore, the purpose of this study is to comprehend Pesce's design, which creates diversity by arranging contingent, non-predictive, and episodic aspects in creative and acceptance processes according to the intension of the designer within mass production system, as a non-representational characteristic, which appears widely in modern thought and the arts, and examine how it is materialized in detailed design work. The study methods are first examining non-representation with theoretical contemplation and dealing with the design philosophy of Pesce based on the examination. Next, in order to discover non-representational characteristics that appear in the work of Pesce, it examines from introducing worker's creativity, user's possibility of choice, openness in the working process, and the aspects of researching materials. And a specific application method will be drawn through case analysis centered on furniture design. Gaetano Pesce's design that denies the world of representation based on the sameness comes to possess non-representational characteristics that acknowledge contingency and ceaselessly create difference by intentionally arranging during the working process.