• Title/Summary/Keyword: rods

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Growth Conditions and Maintenance of Natural Monument Old Big Trees in Gangwondo (강원도 내 천연기념물 노거수의 생육환경 및 관리현황)

  • Heo, Bok Soo;Kim, Hyo Jeong;Lee, Won Ho;Kang, Hee Jin
    • Korean Journal of Heritage: History & Science
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    • v.44 no.1
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    • pp.182-195
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    • 2011
  • Old big tree transcends the simple meaning of trees as they are the natural monuments that embody the people's history and culture of this land. The Cultural Heritage Administration of Korea (CHA) defines and protects old big tree based not only on the size of the tree but also on its definitive cultural and natural factors such as value, implications, and originality. This research aims to identify and analyze the habitation and measurements, the soil conditions, as well as the protective facilities of 14 old big tree spread throughout the Gangwondo. The research examined the soundness of the arboreal form, the degree of damage on the bark, as well as the quantity of leafs levels to evaluate the overall condition of growth and development. Then, the tree height, the eastwest and south-north width of the crown, the sternum circumference, and the root circumference were recorded to identify the measurements of the selected old big tree. Also, the research analyzed 9 elements such as soil texture, pH levels, and organic contents in order to determine the scientific characteristics of soil upon which the trees draw nutrition. Finally, the research evaluated supporting pillars, lightning rods, iron pulling-facilities, as well as notice boards to study the protective facilities of old big tree. The research procedures revealed that 78.57% of the old big tree identified as natural monuments in the Gangwondo have average to above average habitation conditions. Also, the average tree height reaches 18.80m above ground while the average root circumference measures 7.34m. Moreover, the results of the scientific analyses conducted on the soil elements determined that most chemical values were within the defined levels, with the exception of phosphoric acid levels falling within the hyper-nutritious range. Finally, although most of the protective facilities did support the habitation of the Old big tree, there were some supporting pillars and iron pulling-facilities that actually damaged the trees. This research means to provide foundational reference data for the analysis of the habitation and management conditions of natural monument old big tree within the Gangwondo. A follow-up topic led by the results of this research is the identification and analysis of correlating environmental elements that affect the habitation of the old big tree.

Preliminary Result of Revision Fusion Surgery for Thoracolumbar Spine Using Revision Rod (Revision Rod를 이용한 흉요추 유합 재수술 예비 결과)

  • Youn, Yung-Hun;Cho, Kyu-Jung;Park, Ye-Su;Park, Jae-Woo;Park, Jin-Sung;Kwon, Won-Hwan
    • Journal of the Korean Orthopaedic Association
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    • v.55 no.6
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    • pp.520-526
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    • 2020
  • Purpose: The need for revision fusion surgery after spinal fusion has increased. A revision rod that connects to the previous rod was newly developed for revision surgery. The purpose of this study was to analyze the clinical and radiological results after spinal fusion revision surgery using revision rods. Materials and Methods: Twenty-one patients who underwent revision fusion surgery after spinal fusion in two university hospitals with minimum 1 year follow-up were reviewed. This study assessed 16 cases of adjacent-segment disease, four cases of thoracolumbar fracture, and one case of ossification of ligament flavum. The Oswestry Disability Index (ODI) and numerical rating scale (NRS) were evaluated as clinical outcomes, and the union rate, lordosis or kyphosis of the revision level, lumbar lordosis, T5-12 kyphosis, and proximal junctional kyphosis angle were evaluated as the radiological outcomes. Results: The average ODI was 54.6±12.5 before surgery and improved to 29.8±16.5 at the final follow-up. The NRS for back pain and leg pain was 5.0±1.7 and 6.4±2.0 before surgery, which changed to 2.9±1.6 and 2.9±2.2 at the final follow-up. Lumbar lordosis was 18.1°±11.9° before surgery and 21.1°±10.3° at the final follow-up. Proximal junctional kyphosis was 10.8°±10.1° before surgery, and 9.2°±10.5° at the final follow-up. These angles were not changed significantly after surgery. Bony union was successful in all cases except for one case who underwent posterolateral fusion. Conclusion: Revision surgery using a newly developed revision rod on the thoracolumbar spine achieved good clinical outcomes with successful bony union. No problems with the newly developed revision rod were encountered.

Stress Variation Characteristics of Temporary Fixed Steel Rod in FCM Bridge Construction Method (FCM 교량 가설 공법에서 임시 고정 강봉의 응력 변화 특성 )

  • Hyun-Euk Kang;Wan-Shin Park;Young-Il Jang;Sun-Woo Kim;Hyun-Do Yun
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.27 no.3
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    • pp.21-29
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    • 2023
  • In this study, the stress characteristics of temporary fixed steel rods were analyzed in the "temporary fixing system using internal prestressing tension", which is mainly applied to the construction of superstructures by FCM. It was difficult to confirm the changes in initial tensile force in this system because the steel rod was internally connected to the pier and the PSC BOX. Therefore, measurement was performed before and after the completion of each segment using an FBG sensor to measure the change in the micro length of the steel rod. The results of the analysis showed that 75% to 90% of the maximum vertical contraction of the steel rod that occurred until the completion of the cantilever segment occurred in the fixing ~ 1segment, and the maximum loss of initial prestressing force was 39%. Such excessive loss of tension force to 1 segment means that tension is needed to improve the precision of construction during the fixation, and re-tension is needed to secure stability for conduction of cantilever segments after the completion of 1segment. In the 2 ~ last segment, the stress of the steel rod decreased gradually, and in the summer, the decrease in stress tended to partially recover due to the increase in the length of the steel rod corresponding to the increase in the vertical volume of PSC BOX. The dominant factor in the stress change in 2~ last segment in this phenomenon is judged to be the change in the length of the steel rod according to the temperature. Unlike the change in length, the relaxation was 1.2-2.7%, which was mostly offset by the opposite stress corresponding to the temperature stress. Therefore, a plan was proposed to improve the internal stress, such as adjusting the fixation time.

Rare-Earth Metal Complex-Functionalized Mesoporous Silica for a Potential UV Sensor (잠재적인 UV 센서를 위한 희토류 금속착물이 기능화된 메조다공성 실리카)

  • Sung Soo Park;Mi-Ra Kim;Weontae Oh;Yedam Kim;Yeeun Lee;Youngeon Lee;Kangbeom Ha;Dojun Jung
    • Journal of Adhesion and Interface
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    • v.24 no.4
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    • pp.136-142
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    • 2023
  • In this study, TEOS was used as a silica source, and a triblock copolymer (P123) was used as a template to produce mesoporous silica with a well-ordered hexagonal mesopore array through a self-assembly method and hydrothermal process under acidic condition. (Surfactant-extracted SBA-15). Surfactant-extracted SBA-15 showed the particle shape of a short rod with a size of approximately 980 nm. The surface area and pore diameter were 730 m2g-1 and 70.8 Å, respectively. Meanwhile, aminosilane (3-aminopropyltriethoxysilane, APTES) was grafted into the mesopores using a post-synthesis method. Mesoporous silica (APTES-SBA-15) modified with aminosilane had a well-ordered pore structure (p6mm) and well-maintained the particle shape of short rods. The surface area and pore diameter of APTES-SBA-15 decreased to 350 m2g-1 and 60.7 Å, respectively. APTES-modified mesoporous silica was treated with a solution of rare earth metal ions (Eu3+, Tb3+) to synthesize a mesoporous silica material in which rare earth metal complexes were introduced into the mesopores. (Eu/APTES-SBA-15, Tb/APTES-SBA-15) These materials exhibited characteristic photoluminescence spectra by λex=250 nm. (5D47F5 (543.5 nm), 5D47F4 (583.5 nm), 5D47F3 (620.2 nm) transitions for Tb/APTES-SBA-15; 5D07F0 (577.7 nm), 5D07F1 (592.0 nm), 5D07F2 (614.9 nm), 5D07F3 (650.3 nm) and 5D07F4 (698.5 nm) transitions for Eu/APTES-SBA-15)