• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.07b
• /
• pp.785-787
• /
• 2002

Conductivity and transmittancy of ZnO is very excellent and the price is low. So the study of transparent electrode materials and electromagnetic wave shielding wall is actively in progress. We add $Al_2O_3$(0.0, 2.0, 3.0, 5.0wt%) to ZnO and observe microscopic structure and conductivity. For XRD observation, Al peak of AZO is increased by increasing the amount of $Al_2O_3$. We observe that the size of grain is reduced by increasing the liquid phase of grain boundary to SEM observation. Conductivity of AZO is increased by increasing the amount of $Al_2O_3$. We confirm the application possibility of the materials for electromagnetic wave reflection materials.

• East Asian mathematical journal
• /
• v.36 no.1
• /
• pp.73-79
• /
• 2020

A ring R is called generalized regular if for every nonzero x in R there exists y in R such that xy is a nonzero idempotent. In this paper, we observe some equivalent conditions for the generalized regular rings that are abelian in terms of idempotents, and we also investigate the primitivity of an idempotent for such a ring. By using the investigation, we characterize such a kind of rings that are noetherian by showing that an abelian generalized regular ring R is noetherian if and only if R is isomorphic to a direct product of finitely many division rings. We also observe some interesting consequences of our results.

• Publications of The Korean Astronomical Society
• /
• v.16 no.1
• /
• pp.43-47
• /
• 2001

We developed a CCD camera that can observe wide fields on the sky. We tested the field of views using various lenses. For cooling the CCD chip, we used a thermoelectric cooling device and tested the cooling efficiency. This camera will continuously observe a part of the sky. The data from the camera will be used to decide the current weather condition by the real-time star counting program (SCount) which will be developed later.

• International Journal of Human Ecology
• /
• v.8 no.1
• /
• pp.19-26
• /
• 2007

The object of this research was to observe the female college 220 students of aged 19-24 for four years and to examine somatotypes distribution; this research intends to contribute to the fitness of clothes by studying the body distribution that affects the clothing structure. The measurement and wearing experiment for somatotypes are done years annually. The average, standard deviation and coefficient of variation was calculated by the SAS program. The research results are as follows: The three somatotypes of side view silhouette (straight type, bend-forward type, lean-back type) showed fairly even distribution. As a result of dressing experiment with the basic bodice pattern, the most influential factor on its suitability was found to be the neck area, shoulder and ease of bodice respectively. The partial body types to observe were categorized as: shoulder(normal, slope, squared), bust(A cup, B cup, C cup), hips (normal, droop, projecting). As for the result for full body type by BMI, normal type was most dominant, and for the categorization by drop, the type A which is with small breasts and large hips was most prevalent.

• KSBB Journal
• /
• v.28 no.5
• /
• pp.327-331
• /
• 2013

This study aimed to observe the effects of Sea Buckthorn seed extracts (SEB) on anti-oxidation and antiinflammation. SEB were found to strongly depress ROS production depending on concentration, and 46.5% anti-oxidation effects were found in the top concentration of 100 ${\mu}g/mL$. Histamine and arachidonic acid release were measured to observe the effects of SEB on anti-inflammation. SEB inhibited histamine release and arachidonic acid release on dose dependent manner. Based on the results above, the conclusion is drawn that SEB have the potential to be used as natural materials that are effective for anti-oxidation and antiinflammation.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2003.10a
• /
• pp.99-102
• /
• 2003

This paper aims to observe the micro-mechanical behaviour of tow geometry during deformation of dry woven carbon-fiber fabric. With the increment of shear angle fabric experiences 'lock-up'phenomenon. In this paper, deformation of micro-mechanical parameters such as tow interval, change in tow amplitude and wavelength are investigated. To observe the micro-deformation of the fabric structure, appropriate specimens from bias extension and biaxial tests are sectioned and observed under the microscope. It was found that different loading conditions cause geometric deferences in the tow architecture.

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.1234-1235
• /
• 2008

To add Nanofiller in the epoxy which is used with the solid insulation material of existing and is a research which observes the improvement of the structural quality to produce the Nanocomposite. Montmorillonite uses with Nanofiller, MMT of the content expense (wt%) which is various and mixed an epoxide and produced sample. According to content of the sample result MMT according to respectively content expense to measure SEM photographing which is the possibility of knowing the minute structure of section with sample where is produced and the tensile strength will be able to observe the change of quality. MMT silicate layer uniformly more in the result and within epoxy matrix, being dispersed, will be able to observe.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.31 no.3 s.258
• /
• pp.373-379
• /
• 2007

In this study, we observe the application of shape memory alloy(SMA) into smart structures for repeatable actuation, because SMA changes its material properties and characteristics progressively under cyclic loading conditions and finally reaches stable path(state) after a certain number of stress/temperature loading-unloading cycles, so called 'training'. In this paper, SMA wires that have been in a stable state through the training are used. Stress-strain curve of the SMA wire at different temperature levels are measured. In addition, we observe other important effects such as the rate effect according to strain rates for rapid actuation response. The current work presents the experimental test using SMA wire after training completion by mechanical cycling. Through these tests, we measure the characteristics of SMA. With the estimated SMA properties and effects, we compare the experimental results with the simulation results based on the SMA constitutive equations.

• Proceedings of the KSME Conference
• /
• 2001.06a
• /
• pp.96-101
• /
• 2001

The development of a new experimental method is required to easily observe the growth behavior of fatigue cracks. To satisfy the requirement, an image processing technique was introduced to fatigue testing. The length of surface fatigue crack could be successfully measured by the image processing system. At first, the image data of cracks were stored into the computer while the cyclic loading was interrupted. After testing, crack length was determined using image processing software which was developed by ourselves. Block matching method was applied to the detection of surface fatigue cracks. By comparing the data measured by image processing system with the data measured by manual measurement with a microscope, the effectiveness of the image processing system was established. If the proposed method is used to monitor and observe the crack growth behavior automatically, the time and efforts for fatigue test could be dramatically reduced.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.51 no.3
• /
• pp.133-141
• /
• 2002

Most maximum power point tracking(MPPT) control algorithm is based on Perturb and Observe(P&O) and Incremental Conductance(IncCond). In comparison with P&O and IncCond algorithm, the dynamic and tracking characteristic of IncCond algorithm is better than P&O algorithm in condition of rapidly changing solar radiation. But in the case of digital implementation, the InCond algorithm has error en decision of maximum power operation point(MPOP). To solve this problem, this paper proposes a improved IncCond algorithm, which can determine the MPOP correctly by inserting the test signal in control input. This paper proposes a novel MPPT control algorithm for the digitally implemented photovoltaic system in condition of rapidly changing solar radiation. To verify the validity of the proposed control algorithm. the computer simulation and experiment are carried out.