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Effect of Application of Organic Fertilizer on the Growth of Korea Lawngrass(Zoysia matrella L. Merr.) by base-dressing and top-dressing application (기비 및 추비에 의한 유기질비료의 사용이 금잔디(Zoysia matrella L. Merr.)의 생육에 미치는 영향(影響))

  • Ham, Suon-Gyu;Lee, Jyung-Jae;Kim, In-Seob
    • Journal of the Korea Organic Resources Recycling Association
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    • v.2 no.1
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    • pp.41-49
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    • 1994
  • This experiment was carried out in order to study the effect of organic fertilizer on the growth of Korean lawngrass (Zoysia matrella L. Merr.) and the change of soil chemical characteristics. The results obtained are summarized as follows : 1. Organic fertilizer was appropriate for base-dressing in the sod establishment of Korean lawngrass(Z. matrella L. Merr.) 2. Chlorophyll contents in mixed application plot of complex fertilizer(21-17-17) and organic fertilizer were more abundant than that in single application plot of organic fertilizer. 3. Application of organic fertilizer promotes the contents of available phosphorous in soil. 4. Dry weights of base-dressing and top-dressing plot had more weight about 40%, 12% than that of control plot, respectively. So base-dressing was more effective than top-dressing in the application of organic fertilizer.

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Study on the Effective Stiffness of Base Isolation System for Reducing Acceleration and Displacement Responses

  • Kim, Young-Sang
    • Nuclear Engineering and Technology
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    • v.31 no.6
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    • pp.586-594
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    • 1999
  • To limit both the large displacement and acceleration response of the structure efficiently, the relationships between acceleration and displacement responses of the structure under several earthquakes are investigated for various horizontal stiffness of the base isolation system to determine the effective stiffness of the base isolation system in this paper. An example structure is a five-storey steel frame building as the primary structure and the secondary structures are assumed to be located on the fifth floor of the primary structure. Input motions used in the structural analysis are El Centre 1940, Taft 1952, Mexico 1985, San Fernando 1971 Pacoima Dam, and artificially generated earthquakes. The relationships of the absolute peak acceleration and the displacement at the top of the structure are calculated for various natural periods of base isolators under various earthquakes. The peak acceleration response of the fifth floor in the base isolated structure is significantly reduced by a factor of 2.1 through 6.25. Also, the relative displacement response of the floor to the base of the superstructure is very small. The results of this study can be utilized to determine the effective stiffness of the base isolation system.

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Environmentally Friendly Moisture-proof Paper with Superior Moisture Proof Property (I) -Properties of Moisture Proof Chemicals- (방습 효과가 우수한 환경친화적 방습지(제1보) -방습제의 특성-)

  • 유재국;조욱기;이명구
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.33 no.4
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    • pp.15-20
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    • 2001
  • The function of the moisture-proof paper is to prevent moisture from adsorbing into the packed goods. Water-vapor transmission rate of the moisture-proof paper should be less than 100g/$m^2$.24hr and the optimum rate would be less than 50g/$m^2$.24hr. In general the moisture-proof paper has been made by laminating polyethylene or polypropylene on top of the base paper. However this kind of moisture-proof paper has a problem in recycling so that it brings about environmental pollution. In general the moisture-proof paper has been made by laminating polyethylene or polypropylene on top of the base paper. However this kind of moisture-proof paper has a problem in recycling so that it brings about environmental pollution. The purpose of this paper was to make moisture-proof paper using the mixture of SB latex and wax emulsion which was recyclable and environmentally friendly. Water vapor transmission rate showed less than 50g/$m^2$.24hr in mixture ratio of 85:15, 87:13, 90:10. Especially the mixture ratio of 87:13 showed the most favorable water-vapor transmission rate. However, the moisture-proof layer was destroyed slightly by folding in packing. It has been observed that there was no close relationship between water-vapor transmission rate of the moisture-proof paper and grammage of the base paper, but the density of base paper had influenced on water vapor transmission rate. It was also observed that the moisture-proof paper could be recycled. The moisture-proof paper was similar to base paper in degree of the pulping, and there was no significant difference in dispersion between moisture-proof paper and base paper. Most of wax particles which caused the spots during drying process could be removed by flotation process. Tensile strength and tear strength of both moisture-proof paper and base paper after pulping were measured to examine the fiber bonding, and no significant difference in physical properties was observed.

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The Discourse for Academic Generation of 'School library Education Science' (문헌정보교육학의 학문적 생성 담론)

  • Hahm, Myung-Sik
    • Journal of the Korean Society for Library and Information Science
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    • v.42 no.4
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    • pp.223-241
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    • 2008
  • This study presents the discourse for academic generation of 'School Library Education Science' based on integrative research between library & information science and education science. The study discusses research fields and themes of 'School Library Education Science' as the base to define the roles of the school library and of teacher-librarians. It contributes to upgrading the research level of the school library. The research field in the school library analyzes and integrates both aspects of library & information science and of education science. The developed theories of 'School Library Education Science' present Library-Based Education and Library-Based Learning, Base Connectionism, Base Integrationism, Top456 Approach, Curriculum-Based Approach, Viewpoint Approach, and Education of Information and the Library as a Subject Matter. The trends in research of the school library analyze the thesis numbers of academic journals. The future research challenges of 'School Library Education Science' discuss the educational basics of the school library, operational management, electronic school libraries, and educational activities. Conclusively, this study analyzes the current situation of the school library & of teacher-librarians in Korea, and provides its solution by the aspects of 'School Library Education Science'.

Static Bending Performances of Cross-Laminated Wood Panels Made with Tropical and Temperate Woods

  • Byeon, Jin-Woong;Kim, Tae-Ho;Yang, Jae-Kyung;Byeon, Hee-Seop;Park, Han-Min
    • Journal of the Korean Wood Science and Technology
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    • v.46 no.6
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    • pp.726-734
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    • 2018
  • In this study, for using effectively domestic (temperate) small and medium diameter logs as a wooden floorboard, cross-laminated wood panels were manufactured using domestic larch and tulip woods as a base material for teak and merbau wood flooring, and static bending strength performances were measured to investigate the applicability as the base materials of wooden flooring in place of plywood. Static bending MOE was much influenced by the strength performances of the top layer lamina than that of the laminae for base materials. Bending MOR showed the higher values in tulip wood that was hardwoods than in larch wood that was softwoods regardless of the strength performances of the top layer laminae, and it was found that the values were much influenced by the strength performances of the base materials used in the core and bottom layers. However these values were 1.4-2.5 times higher values than the bending strength of the wooden floorboards specified in KS, it was found that it can be sufficiently applied to the base materials of wooden floorboards in place of plywood.

Shaking Table Test of the Model of Five-story Stone Pagoda of Sang-Gye-Sa Mounted on Base Isolation Systems (쌍계사 오층석탑모델에 대한 지진격리효과 진동대실험)

  • 김재관;이원주;김영중;김병현
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2001.09a
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    • pp.331-338
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    • 2001
  • Seismic performances of the base isolated model of Five Story Stone Pagoda were studied through shaking table tests. Friction pendulum system (FPS), Pure-friction system with laminated rubber bearing (LRB) and Ball with rubber bearing were selected fur the comparison of performances. Performances of specially designed isolation systems were tested dynamically using shaking table. The test results of isolated model are compared with those of fixed base model. Compared with fixed base model, the isolated model showed that it could withstand much higer intensity of earthquake motion. The Effective Peak Ground Acceleration (EPGA) value of isolated model when the top component tipped over was above twice of that value in case of fixed base model. According to the additional test results, the lower value of coefficient of friction than that of common frictional base isolation systems is more effective to protect the piled multi-block system of Pagoda against moderate intesity of ground motion.

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2.5 Inch HDD Spindle Vibration with Flexible Base Plate

  • Heo, Bae-Kho
    • 정보저장시스템학회:학술대회논문집
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    • 2005.10a
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    • pp.210-214
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    • 2005
  • The purpose of this paper is to study the effects of the flexibility of HDD base plates on spindle vibration via theoretical predictions and experimental measurements. The flexibility of the base plate can significantly affect HDD spindle vibration. This is the most prominent feature in 2.5 inch HDD. Nevertheless, theoretical analysis of the spindle vibration often neglects the flexibility of the non-rotating part including spindle, base plate, and top cover. Our theoretical model developed in University of Washington can include the flexibilities of spindle and base plate. As a result, our theoretical prediction generally agrees well with our experimental measurements in vibration analysis. Moreover, Because of its small form factor, industrial practice is to use flanged disks instead of regular disks in vibration testing of prototypes. Our experimental measurements indicate that flanged disks and regular disks have very different behavior when the frequency is above 1 KHz.

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2.5 Inch HDD Spindle Vibration with a Flexible Base Plate

  • Heo, Baek-Ho
    • Transactions of the Society of Information Storage Systems
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    • v.2 no.2
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    • pp.111-116
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    • 2006
  • The purpose of this paper is to study the effects of the flexibility of HDD base plates on spindle vibration via theoretical predictions and experimental measurements. The flexibility of the base plate can significantly affect HDD spindle vibration. This is the most prominent feature in 2.5 inch HDD. Nevertheless, theoretical analysis of the spindle vibration often neglects the flexibility of the non-rotating part including spindle, base plate, and top cover. Our theoretical model developed in University of Washington can include the flexibilities of spindle and base plate. As a result, our theoretical prediction generally agrees well with our experimental measurements in vibration analysis. Moreover, because of its small form factor, industrial practice is to use flanged disks instead of regular disks in vibration testing of prototypes. Our experimental measurements indicate that flanged disks and regular disks have very different behavior when the frequency is above 1 KHz.

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The Pumping Characteristics of the Valveless Peristaltic Micropump by the Variation of Design Parameters

  • Chang, In-Bae;Park, Dae-Seob;Kim, Byeng-Hee;Kim, Heon-Young
    • KSTLE International Journal
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    • v.3 no.2
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    • pp.101-109
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    • 2002
  • This paper presents the fabrication and performance inspection of a peristaltic micropump by flow simulation. The valve-less micropump using the diffuser/nozzle is consists of base plate, mid plate, top plate and connection tubes fur inlet and outlet. In detail, the base plate is composed of two diffuser nozzles and three chambers, the mid plate consists of a glass diaphragm for the volumetric change of the pumping chamber. The inlet and outlet tubes are connected at the top plate and the actuator fur pressing the diaphragm is located beneath the top plate. The micropump is fabricated on the silicon wafer by DRIE (Deep Reactive ion Etching) process. The pumping performances are tested by the pneumatic test rig and compared with the simulated results fur various dimensions of diffuser nozzles. The pumping characteristics of the micropump by the volumetric change at the pumping chamber is modeled and simulated by the commercial software of FLOW-3D. The simulated results shows that reverse flow is the inherent phenomena in the diffuser nozzle type micropump, but it can be reduced at the dual pumping chamber model.