• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.05d
• /
• pp.61-64
• /
• 2003

This paper presents Bi thin films have been fabricated by atomic layer-by-layer deposition and co-deposition at an IBS method. The growth rates of the films was set in the region from 0.17 to 0.27 nm/min. Mg(100) was used as a substrate. In order to appreciate stable existing region of Bi 2212 phase with temperature and ozone pressure, the substrate temperature was varied between 655 and $820^{\circ}C$ and the highly condensed ozone gas pressure$(PO_3)$ in vacuum chamber was varied between $2.0{\times}10^{-6}$ and $2.3{\times}10^{-5}$ Torr. Bi 2212 phase appeared in the temperature range of 750 and $795^{\circ}C$ and single phase of Bi 2201 existed in the lower region than $785^{\circ}C$. Whereas, $O_3$ dependance on structural formation was scarcely observed regardless of the pressure variation. And high quality of c-axis oriented Bi 2212 thin film with $T_c$(onset) of about 90 K and $T_c$(zero) of about 45 K is obtained. Only a small amount of CuO in some films was observed as impurity, and no impurity phase such as $CaCuO_2$ was observed in all of the obtained films.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.24 no.5
• /
• pp.190-195
• /
• 2014

Because of the temperature gradient occurring during the growth of the ingot with directional solidification method, defects are generated and the residual stress is produced in the ingot. Changing the growth and cooling rate during the crystal growth process will be helpful for us to understand the defects and residual stress generation. The defects and residual stress can affect the properties of wafer. Generally, it was found that the size of grains and twin boundaries are smaller at the top area than at the bottom of the ingot regardless of growth and cooling condition. In addition to that, in the top area of silicon ingot, higher density of dislocation is observed to be present than in the bottom area of the silicon ingot. This observation implies that higher stress is imposed to the top area due to the faster cooling of silicon ingot after solidification process. In the ingot with slower growth rate, dislocation density was reduced and the TTV (Total Thickness Variation), saw mark, warp, and bow of wafer became lower. Therefore, optimum growth condition will help us to obtain high quality silicon ingot with low defect density and low residual stress.

• Journal of the Korean housing association
• /
• v.13 no.5
• /
• pp.77-88
• /
• 2002

This article deals the investigations how to solve the social deficiencies of deteriorate apartments, which is a half cycle of a building and it goes slum clearance and redevelopment. And this proposes an active remodeling and design strategy, management, and housing policies for extending the usage of the resource. Most of apartment housing in Korea is built by the panel wall and slab structure system fur economic price. To remake is possible, even though not designed in flexibility and variation. The remodeling strategies are dwelling unification, transformation of two units to one or three units, addition of a room, changing into commercial and community required spaces, and reshaping of a envelop and facade by addition of a dwelling or dwellings, roof floors, change of materials and colors, and so on. And, all activities in structural aspect are proposed removal in upper part and addition in lower part of an apartment housing. Active remodeling cost a great deal compare to new construction, so any remodeling activities should be based on a minimal interfere and budgets to enhancing the quality in existing building. The final aim of an active remodeling is to enhance the quality in economic values, and to keep original state and to put on the new one in a small part. To promote the active and careful management and rehabilitation, it is necessary to give the positive incentive in terms of architectural law, bank loan, and any redevelopment project should get the remodeling record in national resources.

• Journal of the Korean earth science society
• /
• v.31 no.1
• /
• pp.36-50
• /
• 2010

The purpose of this study is to investigate the aspect of variation of the texts in elementary and secondary school science textbooks at each grade level in terms of linguistic features. Data included some of the written texts related to 'Volcano and Earthquake' in Korean elementary and secondary school science textbooks in the seventh National Curriculum. The written texts were comparatively analyzed in terms of textual meaning, interpersonal meaning, and ideational meaning. Results revealed that there were different structures and linguistic features of the texts in school science textbooks depending on the grade level. Therefore, we argue that the differences in this study may make students feel difficult and strange when they read and understand science textbooks. We suggest that science teachers need to play the role of a mediator between students' understanding and the structural features of the scientific language in science learning.

• The KSFM Journal of Fluid Machinery
• /
• v.10 no.2 s.41
• /
• pp.41-45
• /
• 2007

The shutoff unit was designed to provide rapid insertion of neutron absorbing material into the reactor core to shutdown the reactor quickly and also to withdraw the absorber slowly to avoid a log-rate trip. Four shutoff units were installed on the HANARO reactor but the half-core test facility was equipped with one shutoff unit. The reactor trip or shutdown is accomplished by four shutoff units by insertion of the shutoff rods. The shutoff rod(SOR) is actuated by a directly linked hydraulic cylinder on the reactor chimney, which is pressurized by a hydraulic pump. The rod is released to drop by gravity, when triplicate solenoid valves are de-energized to vent the cylinder. The hydraulic pump, pipe and air supply system are provided to be similar with the HANARO reactor. The shutoff rod drops for 647mm stroke within 1.13 seconds to shut down the reactor and it is slowly inserted to the full down position, 700mm, with a damping. We have conducted the drop test of the shutoff rod in order to show the performance and the structural integrity of operating system of the shutoff unit. The present paper deals with the 647mm drop time and the withdrawal time according to variation of the pool water temperature, the water level and the core flow.

• Korea Journal of Hospital Management
• /
• v.14 no.4
• /
• pp.124-148
• /
• 2009

Objectives : The purpose of this study was to investigate influencing factors on physician's intention to use cyber salesperson(cSP) to promote ethical drugs of pharmaceutical company. We considered influencing factors based on technology acceptance model(TAM) such as usefulness, easy of use, and attitude about cSP, and included trust and joyfulness of cSP. Methods : Measure items were developed from the previous studies. Data were collected from 1,012 physicians by using web-based self-administered structured questionnaire. Results : The major findings were as follows; First, attitude and intention to use cSP were not significantly varied by socio-demographic variables, such as sex, age, location, and Internet surfing time per day. Also, physician's characteristics such as training and professional level and type of employment were not significant to the variation of attitude and intention to use cSP. Second, structural equation modeling(SEM) analysis shows that usefulness and joyfulness were influencing factors of intention to use. Attitude was revealed as significant mediating factor to intention to use. Usefulness has indirect effect on intention to use via attitude. However, trust has not significant effect on intention to use, due to suppression effect. Conclusions : This results implies that cSP will be a useful agent to promote the ethical drugs to physician. Usefulness and joyfulness should be considered as important factors in designing and operating cSP in the Internet.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.32 no.5A
• /
• pp.267-275
• /
• 2012

This paper describes the experimental study on the structural behavior of the joint plane between a RC(Reinforced Concrete) wall and a SC(Steel Plate Concrete) wall under out-of plane flexural loads and in-plane shear loads. The test specimens were produced with L and I shape to assess efficiently flexural and shear behavior of the structures. In order to consider dynamic loads such as earthquake, cyclic loading tests were carried out. As results of the out-of plane flexural tests, ductile failure mode of vertical bars was shown under a push load and the failure load was more than nominal strength of the specimen. And the latter test was performed to verify the variation which was composition presence of horizontal bars in the SC member. The test results showed that capacity of the specimens was more than their nominal strength regardless of composition presence of horizontal bars.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.34 no.1
• /
• pp.1-8
• /
• 2014

This paper deals with monitoring and analysis of temperature measurement data in concrete pylon of long span cable bridges. During the construction of Geoga Bridge in Busan-Geoje Fixed Link Project, temperature sensors were installed in several sections of hollow box type concrete pylon and temperatures along the depth of the four sides of the section have been recorded along with ambient temperature. Effects of temperature distribution on the pylon are analysed using actual measured data and results are compared with the design guideline. It was found that the temperature load model for concrete girder can be applied to box type concrete pylon. Structural analysis of the pylon due to variation of temperature distribution during the construction is performed using 3D modelling and FE program and the maximum displacements of east-west and north-south side were calculated as 0.056m and 0.121m, respectively.

• Journal of Advanced Marine Engineering and Technology
• /
• v.31 no.2
• /
• pp.173-181
• /
• 2007

Recently, galvanizing method is predominantly being used not only a economical point of view but also due to it s stability and long life. For example, guard rail of high way, all kinds of structures for ship etc. were protected with galvanizing and demand of galvanized structural materials was being increased with more and more. However, galvanized structures were inevitably being deteriorated with time eventually because they were corroded with solution of galvanizing film and exfoliation of it s film in the present severe corrosive environment. Therefore, it is necessary to improve the corrosion resistance of the galvanizing film through various methods such as variation of chemical composition of galvanizing bath, chromate treatment and coating treatment. In this study, three test specimens such as pure galvanizing, galvarium, and chromate treatment were submerged at tap water with inhibitor addition. And the effect of their corrosion resistance improvement was comparatively investigated with electrochemical method. Corrosion current density of the galvanized steel was the largest among three specimens, however, the galvarium steel showed the lowest corrosion current density. Futhermore, these three kinds of test specimens indicated considerably excellent corrosion resistance by dipped at tap water with inhibitor addition. Especially, the galvanized steel showed the best effect of corrosion resistance improvement than other test specimens.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.35 no.3
• /
• pp.221-228
• /
• 2011

The large-area crystallization of amorphous silicon thin films on glass backplanes is one of the key technologies in the manufacture of flat-panel displays. Joule-heating induced crystallization (JIC) is a recently introduced crystallization technology. It is considered a highly promising technique for fabricating OLEDs, because the film of amorphous silicon on glass can be crystallized in tens of microseconds, minimizing thermal and structural damage to the glass. In this study, we theoretically and experimentally investigated the temperature variation during the phase transformation. The critical temperatures for crystallization were determined for both solid-solid and solid-liquidsolid transitions, by carrying out in-situ temperature measurements and numerical analysis of the JIC.