• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.28 no.5
• /
• pp.338-343
• /
• 2015

Dye sensitized solar cells (DSSCs), which is one of the contending renewable energy sources, have the problem of low efficiency. To improve the efficiency, the fast electron transport and long electron lifetime are required. In this study, one-dimensional sodium hexatitanate, which is expected to have an advantageous structure for electron transports, was synthesized and the feasibility of the material on DSSC was tested. Its physical properties were characterized by the SEM, XRD, and BET method. The dye adsorption and solar cell properties were also characterized. In addition to the expectation of fast electron transport, sodium hexatitanate showed longer electron lifetime: This means sodium hexatitanate can improve the DSSC efficiency. However, it showed low current and voltage because of the low surface area leading to the low amount of dye adsorbed. Therefore, it should be mixed with titanium oxide with high surface area for the optimal performance.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.21 no.4
• /
• pp.608-612
• /
• 2012

To reduce these costs and time by finite element analysis program has been much research (3~4). At virtual CAE program as like Abaques, Ansys, Ls-dyna and Nastran, the input data of material is got bellow coupon test. In case of carbon composite, it is also put in lamina/laminate properties. There have big problem. If you want to simulate FW(filament winding or wind blade) how do you input material data. Each area of FW is different stacking conditions. It's too hard that each area is tested for inputting lamina or laminate properties. The composite structure increasing load is applied occurred as the matrix dependence of the crack-induced nonlinearity and nonlinear mobility appears since the initial damage. And uni-direction for this research applies the theory to have been confined to. On this study, we are going to get basically fiber properties and matrix than carbon composite properties for simulating according stacking method by GENOA-MCQ. It is help to simulate easily composite material. Also Calculate the matrix nonlinear for simulating non-linear.

• Journal of Periodontal and Implant Science
• /
• v.44 no.5
• /
• pp.259-264
• /
• 2014

Purpose: The aim of this case report is to present the longitudinal results of sinus grafting using a new demineralized bovine bone material (DBBM) in human cases. Methods: A patient with a resorbed maxilla was treated by maxillary sinus grafting using a new deproteinized bovine bone material. After a healing period of 6.5 months, three implants were placed and restored. The patient was periodically recalled and followed up for 5 years after restoration. Results: Twelve partially edentulous patients (average age, 55.7 years) were followed up. All patients had insufficient residual height in their maxillary posterior area and underwent maxillary sinus graft surgery to increase the height of their maxilla. In all, 27 fixtures were placed in the augmented bone area. On average, 8.6 months later, implants were loaded using provisional or final restorations. The observation period ranged from 27 to 75 months (average, 43.3 months), and the patients did not show any severe resorption of the graft material or any infection during this time. Conclusions: Our results show that the new DBBM is useful for a maxillary sinus graft procedure. Good healing responses as well as reliable results were obtained for an average follow-up period of 43.3 months.

• Korean Journal of Materials Research
• /
• v.26 no.11
• /
• pp.662-669
• /
• 2016

In order to identify changes in the nature of the particles due to changes in the inflow rate of the raw material solution, the present study was intended to prepare nano-sized cobalt oxide ($Co_3O_4$) powder with an average particle size of 50 nm or less by spray pyrolysis reaction using raw cobalt chloride solution. As the inflow rate of the raw material solution increased, droplets formed by the pyrolysis reaction showed more divided form and the particle size distribution was more uneven. As the inflow rate of the solution increased from 2 to 10 ml/min, the average particle size of the formed particles increased from about 25 nm to 40 nm, while the average particle size did not show significant changes when the inflow rate increased from 10 to 50 ml/min. XRD analysis showed that the intensity of the XRD peaks increased remarkably when the inflow rate of the solution increased from 2 to 10 ml/min. On the other hand, the peak intensity stayed almost constant when the inflow rate increased from 10 to 50 ml/min. With the increase in the inflow rate from 2 to 10 ml/min, the specific surface area of the particles decreased by approximately 20 %. On the contrary, the specific surface area stayed constant when the inflow rate increased from 10 to 50 ml/min.

• Journal of the Korean Electrochemical Society
• /
• v.24 no.1
• /
• pp.1-6
• /
• 2021

In this study, new morphology of NCA cathode material for lithium ion batteries was obtained through the electrospinning method. The prepared NCA nanofibers formed a nano-bush structure, and the primary particles were formed on the surface of the nanofibers. The embossing primary particles increased the surface area thus increasing the reactivity of lithium ions. The nano-bush structure could shorten the Li+ diffusion path and improve the Li+ diffusion coefficient. Scanning electron microscopy (SEM) revealed that the synthesized material consisted of nanofibers. The surface area of the nanofibers increased by primary particles was measured using atomic force microscopy (AFM). X-ray diffraction (XRD) analysis was carried out to determine the structure of the NCA nanofibers.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2008.10a
• /
• pp.842-853
• /
• 2008

In the construction of dam, the key factor which decides the type of dam is security of materials resource. Because of the large scale earth work, the ability to supply the materials is essential part about economical efficiency. The research is the case study about controlling the plan to secure the material resources in the design of Buhang multipurpose dam. In case of Buhang multipurpose dam, at that time of basic design, it was planned to use a rock fill material. From the detail investigation about the river bed accumulative layer widely spread on the submerged district on the basic design, the research is accomplished to replace rock material with gravel material. After the investigation of whole reserves of gravel material, estimation of conformity as dam construction material from analysis of grain size distribution, the case study of oversea construction, and the material property comparison between rock fill material and gravel fill material, it is verified th possibility of using the gravel fill. Thereafter, the analysis of dam stability using a gravel fill material is accomplished. Finally, A gravel fill material can be used as the main construction material of CFRD, therefore the efficiency of resource recycling in the submerged area is maximized, and the established plan is more advantageous to stability, constructibility, environmentibility than the case of using a rock fill.

• KIPS Transactions on Software and Data Engineering
• /
• v.9 no.1
• /
• pp.33-38
• /
• 2020

This paper proposes a technique for counting construction materials by analyzing an image acquired by a Drone. The proposed technique use drone log which includes drone and camera information, RCNN for predicting construction material type, dummy area and Photogrammetry for counting the number of construction material. The existing research has large error ranges for predicting construction material detection and material dummy area, because of a lack of training data. To reduce the error ranges and improve prediction stability, this paper increases the training data with a method of data augmentation, but only uses rotated training data for data augmentation to prevent overfitting of the training model. For the quantity calculation, we use a drone log containing drones and camera information such as Yaw and FOV, RCNN model to find the pile of building materials in the image and to predict the type. And we synthesize all the information and apply it to the formula suggested in the paper to calculate the actual quantity of material pile. The superiority of the proposed method is demonstrated through experiments.

• Cement Symposium
• /
• no.30
• /
• pp.125-131
• /
• 2003

As the material for Out-let(exit area), which is applied at the rotary kiln of cement factory, the castable of high density, with the chemical composition of above 90$\%$ of Alumina and the CCS (Cold Crushing Strength) of above 1000kg/$cm^

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2010.05a
• /
• pp.1289-1290
• /
• 2010

• Journal of the Korean BIBLIA Society for library and Information Science
• /
• v.17 no.2
• /
• pp.137-155
• /
• 2006

Objects which has been used for administration is a part of archives that holding merit of history, merit of evidence and merit of administration. But it does not be treated carefully as archival material also, it can not be found a study for the archival objects. Thus this study aims to suggest a description of the objects for management the objects appropriately. To derive a conclusion, this paper made a comparative by using the archival description of other nations such as General International Standard for Archival Description, Rules for Archival Description also refer to the cataloging rules which used for a long time to management materials at library such as Anglo-American Cataloging Rules, Korean Cataloging Rules. We divided the section into 7 area such as identity statement area, context area, content and structure area, condition of access and use area, allied material area, note area, and description control area for suggest a description for archival objects.