• Title/Summary/Keyword: Instability

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Interpretation of Deformation History and Paleostress Based on Fracture Analysis Exposed in a Trench (트렌치에서의 단열분석을 통해 도출한 단열발달사 및 고응력 해석: 울산 신암리의 예)

  • Gwon, Sehyeon;Kim, Young-Seog
    • The Journal of Engineering Geology
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    • v.26 no.1
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    • pp.33-49
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    • 2016
  • The study area, located in Sinam-ri, Ulsan, in the southeastern part of the Korean Peninsula, is mainly composed of hornblende granite (ca. 65 Ma). Fracturing and reactivation of a fault striking ENE-WSW was strongly controlled by the intrusion of a mafic dyke (ca. 44 Ma), which behaves as a discontinuity in the mechanically homogeneous pluton, increasing the instability of the basement in this area. A geometric and kinematic study undertaken to interpret the faults and fractures was performed in a trench excavated almost perpendicular to the orientation of the dyke. The analysis of structural elements, such as dykes, veins, and faults, is used to infer the deformation history and to determine the paleostress orientations at the time of formation of the structures. The deformation history established based on this analysis is as follows: (1) NNE-SSW, E-W, ENE-WSW, and NE-SW trending fractures had already developed in the pluton before dyke intrusion; (2) felsic dykes intruded under conditions of σHmax oriented N-S and σHmin oriented E-W; (3) mafic dykes intruded under conditions of σHmax oriented E-W and σHmin oriented N-S; (4) dextral reactivation of the main fault associated with the development of hydrothermal quartz veins under conditions of σHmax oriented E-W and σHmin oriented N-S; (5) sinistral reactivation of the main fault and high-angle normal faults under conditions of σHmax oriented NE-SW and σHmin oriented NW-SE; and (6) dextral reactivation of the main fault and NE-SW low-angle reverse faults under conditions of σHmax oriented NW-SE and σHmin oriented NE-SW. These results are consistent with the tectonic history of the Pohang-Ulsan block in the southeastern part of the Korean Peninsula, and indicates the tectonic deformation of the southern area of the Ulsan fault bounded by Yangsan fault was analogous to that of the Pohang-Ulsan area from the Cenozoic. This work greatly aids the selection of sites for critical facilities to prevent potential earthquake hazards in this area.

Internal Waves and Surface Mixing Observed by CTD and Echo Sounder in the mid-eastern Yellow Sea (황해 중동부해역에서 CTD와 음향탐지기로 관측한 내부파와 표층 혼합)

  • Lee, Sang-Ho;Choi, Byoung-Ju;Jeong, Woo Jin
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.18 no.1
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    • pp.1-12
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    • 2013
  • Acoustic backscatter profiles were measured by Eco-sounder along an east-west section in the mid-eastern Yellow Sea and at an anchoring station in the low salinity region off the Keum River estuary in September 2012, with observing physical water property structure by CTD. Tidal front was established around the sand ridge developed in 50 m depth region. Internal waves measured by Eco-sounder during low tide period in the eastern side of the sand ridge were nonlinear depression waves with wave height of 15 m and mean wavelength of 500 m. These waves were interpreted into tidal internal waves that were produced by tidal current flowing over the sand ridge to the southeast. When weakly non-linear soliton model was applied, propagation speed and period of these internal depression wave were 50 m/s and 16~18 min. Red tides by Dinoflagelates Cochlodinium were observed in the sea surface where strong acoustic scattering layer was raised up to 7 m. Hourly CTD profiles taken at the anchoring station off the Keum River estuary showed the halocline depth change by tidal current and land-sea breeze. When tidal current flowed strongly to the northeast during flood period and land-breeze of 7 m/s blew to the west, the halocline was temporally raised up as much as 2 m and acoustic profile images showed a complex structure in the surface layer within 5-m depth: in tens of seconds the declined acoustic structure of strong and weak scattering signals alternatively appeared with entrainment and intrusion shape. These acoustic profile structures in the surface mixed layer were observed for the first time in the coastal sea of the mid-eastern Yellow Sea. The acoustic profile images and turbidity data suggest that relatively transparent low-layer water be intruded or entrained into the turbid upper-layer water by vertical shear between flood current and land breeze-induced surface current.

Effects of Soil Aggregate Stability and Wettability on Infiltration and Evaporation (토양입단(土壤粒團)의 안정성(安定性)과 친수성(親水性)이 수분침투(水分浸透) 및 증발(蒸發)에 미치는 영향(影響))

  • Jo, In-Sang;Cho, Seong-Jin;Verplanke, H.;Hartmann, R.;De Boodt, M.
    • Korean Journal of Soil Science and Fertilizer
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    • v.18 no.2
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    • pp.121-127
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    • 1985
  • This study was designed to gain practical data on the use of soil conditioners for more efficient water managements and to establish the optimum levels of structural properties for soil conditioning. A sandy loam and a silt loam soil were each treated with two different soil conditioners, hydrophobic Bitumen or hydrophilic Uresol. The perspex tube 34 cm long were packed homogeneously with air dried soil up to 2 cm below the top, then covered over 2 cm of treated or untreated aggregates. The infiltration rate into the soil columns was measured under simulated rainfall condition. The evaporation study was carried out in the wind tunnel, and the changes of soil moisture distribution of the columns following and during the evaporation were determined by a gamma ray scanner. The infiltration rate of water into the soil column was increased to 18.7-50.8% by the Uresol treatment but it was decreased to less than 25% of control by the Bitumen treatment. Evaporation was decreased to 22.0-68.1% by the Bitumen treatment and to 38.7-68.4% by the Uresol treatment. The water use efficiency of Uresol treated column was increased to more than twice as much as that of untreated soil. Aggregate stability and wetting angle were related to water infiltration and evaporation. A positive and highly significant logarismic relationship was found between the infiltration rate and stability index-wetting angle, evaporation rate and instability index-wetting angle. It was considered that the structural stability is more important than wetting angle. This is true because the structural stability is always positively correlated to water saving, however wettability is positively correlated to the infiltration, and negatively correlated to water saving during the evaporation.

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The Effects of Sex Education on the Primary Schooler's Knowledge and Attitude about Sex (성교육이 국민학생의 성지식과 성태도에 미치는 효과)

  • Kim, Jin-Son
    • Women's Health Nursing
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    • v.1 no.2
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    • pp.200-221
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    • 1995
  • The confusion of the sense of value on sex is increasing because of the rapid change in social-cultural environment. Also due to a rise in the standard of living, the age of adolescence is getting lower, and so the second sexual marks appear to primary schoolers. At this time in the aspect of the education for the whole man, it's very important for primary schoolers to acquire right knowledge and desirable attitude on sex so that can overcome psychological instability caused by physical growth, be responsible for their behaviors and lead happy lives. This study was made to find out the effects of sex education for the primary schoolers' knowledge and attitude about sex. The study was designed as simulated control group pretest-posttest design, which only pretest was practiced to control group and after sex education only posttest was practiced to experimental group. The data was collected for 18 days from March 13, 1995 to March 31, 1995. The subjects of this study were 130 six-graders in a private primary school in seoul. The control group and experimental group were composed of 65 pupils, each. Sex education consisted of lecture and discussion and the materials were this researcher's own made, 'How do I grow? and related OHP film and video. This education was practiced 40 minutes at a time, at intervals of 2-4 days' six times during 3weeks. For sex knowledge tools, 20 item questionaries on the base of related reference books and contents of this study were used. For sex attitude tools, this researcher's own made 13 item questionaries were used which were revised and complemented and laying stress on the reference books. The data was analyzed through pc-SAS program. The homogeneity test in terms of the general characteristics of experimental and control group was analyzed through $x^2$-test and t-test. And the difference in the primary schoolers' score on knowledge and attitude about sex before and after the sex education was analyzed through t-test and ANCOVA. The results of this study are as follows : 1. The result of the homogeneity test in terms of the general characteristics of the experimental and control group showed that there were significant differences in economic standard($x^2$=2.92, P=0.052) and brotherly ties($x^2$=3.78, P=0.052). 2. Hypothesis 'After sex education, the score of primary schoolers' sex knowledge will be higher than before. 'showed statistically significant difference.(t=11.99, P=.0001) Sex education was practiced under control over subjective view of economic standard and brotherly ties which showed significant difference at the homogeneity test in terms of the general characteristics between the two groups. After this education, the results of comparing the score of primary schoolers' sex knowledge also showed significant difference between the two groups. So hypothesis I was supported since primary schoolers to have education showed noticeable results in the sex knowledge score. (F=16.52, P=.0001) 3. Hypothesis 'After sex education, primary schooler's sex attitude score will be higher than before' showed statistically significant(t=5.08, P=.0001) Sex education was practiced, too, under control over subjective view of economic standard and brotherly ties which showed significant difference at the homogeneity test in terms of the general characteristics between the two groups. Bat this time the results of comparing the primary schoolers' sex attitude showed no significant difference between the two groups. So hypothesis II was rejected since for primary schoolers to have sex education showed no noticeable results in sex attitude score. (F=3.52, P=.0628) These results of the study show that sex education gives affirmative change to the primary schooler's sex knowledge, bat short periods' sex education doesn't give any change to the sex attitude. For the establishment of the pupils' desirable sex attitude, systematic and concrete sex education fit for the pupils' developing stage should be practiced over a long period of time.

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On the manufacturing of WPC (Wood Plastic Composites) with Heat-Catalyst Polymerization (I) - On the characteristics of composites made from monomer Methyl MethacryIate and several commercial woods in Korea (가열(加熱)·촉매중합법(觸媒重合法)에 의한 목재(木材)·고분자복합체(高分子複合體) 제조(製造)(I) - MMA에 의한 한국산(韓國産) 주요목재(主要木材)의 복합체특성(複合體特性))

  • Cho, Nam-Seok;Jo, Jae-Myeong;Ahn, Won-Yong
    • Journal of the Korean Wood Science and Technology
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    • v.2 no.3
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    • pp.3-16
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    • 1974
  • One of the disadvantages of. wood and wood products is their hydroscopicity or dimensional instability. This is responsible for the loss of green volume of lumber as seasoning degrade. Dimensional stabilization is needed to substantially reduce seasoning defects and degrades and for increasing the serviceability of wood products. Recently, considerable world-wide attention has been drawn to the so-called Wood-Plastic Composites by irradiation-and heat-catalyst-polymerization methods and many research and developmental works have been reported. Wood-Plastic Composites are the new products having the superior mechanical and physical properties and the combinated characteristics of wood and plastic. The purpose of this experiment was to obtain the basic data for the improvement of wooden materials by manufacturing WPC. The species examined were Mulpurae-Namoo (Fraxinus, rhynchophylla), Sea-Namoo (Carpinus laxiflora), Cheungcheung-Namoo (Cornus controversa), Gorosae-Namoo (Acermono), Karae-Namoo(Juglans mandshurica) and Sanbud-Namoo (Prunus sargentii), used as blocks of type A ($3{\times}3{\times}40cm$) and type B ($5{\times}5{\times}60cm$), and were conditioned to about 10~11% moisture content before impregnation in materials humidity control room. Methyl methacrylate (MMA) as monomer and benzoyl peroxide (BPO) as initiator are used. The monomer containing BPO was impregnated into wood pieces in the vacuum system. After impregnation, the treated samples were polymerized with heat-catalyst methods. The immersed weights of monomer in woods are directly proportionated to the impregnation times. Monomer impregnation properties of Cheungcheung-Namoo, Mulpurae-Namoo and Seo-Namoo are relatively good, but in Karae-Namoo, it is very difficult to impregnate the monomer MMA. Fig. 3 shows the linear relation between polymer retentions in wood and polymerization times; that is, the polymer loadings are increasing with polymerization times. Furthermore species, moisture content, specific gravity and anatomical or conductible structure of wood, bulking solvents and monomers etc have effects on both of impregnation of monomer and polymer retention. Physical properties of treated materials are shown in table 3. Increasing rates of specific gravity are ranged 3 to 24% and volume swelling 3 to 10%. ASE is 20 to 46%, AE 14 to 50% and RWA 18 to 40%. Especially, the ASE in relation to absorption of liquid water increases approximately with increase of polymer content, although the bulking effect of the polymerization of monomer may also be influential. WPCs from Mulpurae-Namoo and Cheungcheung-Namoo have high dimensional stability, while its of Karae-Namoo and Seo-Namoo are-very low. Table 4 shows the mechanical properties of WPCs from 6 species. With its specific gravity and polymer loading increase, all mechanical properties are on the increase. Increasing rate of bending strength is 10 to 40%, compression strength 25 to 70%, ;impact bending absorbed energy 4 to 74% and tensile strength 18 to 56%. Mulpurae-Namoo and Cheungcheung-Namoo with high polymer content have considerable high increasing rate of strengths. But incase of Karae-Namoo with inferior monomer impregnation it is very low. Polymer retention in cell wall is 0.32 to 0.70%. Most of the polymer is accumulated in cell lumen. Effective. of polymer retention is 58.59% for Mulpurae-Namoo, 26.27% for Seo-Namoo, 47.98% for Cheungcheung-Namoo, 25.64% for Korosae-Namoo, 9.96% for Karae-Namoo and 25.84% for Sanbud-Namoo.

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Surgical Closure of the Patent Ductus Arteriosus in Premature Infants by Axillary Minithoracotomy (액와 소개흉술에 의한 미숙아 동맥관 개존증의 외과적 치료)

  • Cho, Jung-Soo;Yoon, Yong-Han;Kim, Joung-Taek;Kim, Kwang-Ho;Hong, Yung-Jin;Jun, Yong-Hoon;Shinn, Helen Ki;Baek, Wan-Ki
    • Journal of Chest Surgery
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    • v.40 no.12
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    • pp.837-842
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    • 2007
  • Background: Closure of the ductus arteriosus is often delayed in premature infants, which creates a hemodynamically significant left to right shunt that exerts an adverse effect on the normal development and growth of these babies. We reviewed out experience on surgical closure of patent ductus arteriosus via axillary minithoracotomy in premature infants. Material and Method: From April 2002 to October 2006, 20 premature infants whose gestation was under 37 weeks underwent surgical closure of patent ductus arteriosus as a result of complications or contra-indications for the use of indomethacin. Their mean gestational age was 28.8+3.4 weeks, ranging from 25+3 to 34+6 weeks, and the average age at operation was $15.6{\pm}6.3$ days. The mean body weight at operation was $1,174{\pm}416\;g$, ranging from 680 to 2,100g; 16 infants were under 1,500 and 9 infants were under 1,000 g. The procedures were performed in the newborn intensive care unit via $2{\sim}3\;cm$ long axillary minithoracotomy with the infant in the lateral position with left arm abduction. The mean size of the patent ductus arteriosus was $3.8{\pm}0.3\;mm$. For the most part, the ductus was closed with clips; 2 infants in whom the ductus was ruptured while dissection was being performed underwent ductal division. Result: Ten of twelve infants who had been ventilator dependent preoperatively could be successfully weaned from the ventilator at a mean duration of 9.7 days after the operation. There was no procedure-related complication or death. Two infants eventually died of the conditions not related to the operation; one from sepsis at postoperative 131 days and the other from pneumonia at postoperative 41 days, respectively. Conclusion: Surgical closure of the patent ductus arteriosus improved the hemodynamic instability and so promoted the successful growth and normal development of premature infants. Considering the low surgical risk along with the reduced invasiveness, early and aggressive surgical intervention is highly recommended.

Posterior Cruciate Ligament and Posterolateral Structure Reconstruction using Bilateral Hamstring Tendons (양측 슬괵건을 이용한 후방 십자 인대 및 후외측 지대 재건술)

  • In, Yong;Kim, Seok-Jung;Lee, Gyu-Yeong
    • Journal of the Korean Arthroscopy Society
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    • v.9 no.2
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    • pp.167-173
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    • 2005
  • Purpose: The purpose of this study is to evaluate the clinical results of posterior cruciate ligament (PCL) and posterolateral structure (PLS) reconstruction using bilateral hamstring tendon autografts. Materials and Methods: From October 2002 to March 2004, ten patients were received PCL and PLS reconstruction simultaneously using bilateral hamstring autografts. PCL was reconstructed using ipsilateral hamstring tendon and fixed with cross pins and Intrafix (Mitek, Norwood, MA). PLS was reconstructed using contralateral hamstring tendon. The mean follow up was 17 months. Clinical assessments consisted of Lysholm knee scores, International Knee Documentation Committee (IKDC) evaluation form and posterior stress radiographs. External rotation of tibia was evaluated at $30^{\circ}\;and\;90^{\circ}$ knee flexion using Noyes and Barber-Westin's classification. Contralateral harvest site morbity was evaluated using IKDC evaluation form and flexion power of the knee. Results: Mean posterior displacement of tibia using stress radiographs was improved from 13.3 mm to 3.7 mm. In tibial external rotation evaluation, 7 patients were functional, 2 patients were partially functional and one failure. The average Lysholm knee score improved from 54 preoperatively to 86 postoperatively. At the final IKDC evaluation, 8 patients were graded as nearly normal, 2 were graded as abnormal. In contralateral harvest site morbidity evaluation, 2 patients complained of numbness around the wound but negligible. Conclusion: PCL and PLS reconstruction using bilateral hamstring autografts was considered as a good treatment method with minimal contralateral harvest site morbidity.

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Geological Structure of Okcheon Metamorphic Zone in the Miwon-Boeun area, Korea (미원-보은지역에서 옥천변성대의 지질구조)

  • 강지훈;이철구
    • The Journal of the Petrological Society of Korea
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    • v.11 no.3_4
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    • pp.234-249
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    • 2002
  • The Miwon-Boeun area in the central and northern part of Okcheon metamorphic zone, Korea, is composed of Okcheon Supergroup and Mesozoic Cheongju and Boeun granitoids which intruded it. The Okcheon Supergroup consists mainly of quartzite (Midongsan Formation), meta-calcareous rocks (Daehyangsan Formation, Hwajeonri Formation), meta-psammitic rocks (Unkyori Formation), meta-politic rocks (Munjuri Formation), meta-conglomeratic rocks (Hwanggangni Formation) in the study area, showing a zonal distribution of NE trend. Its' general trend is locally changed into NS to EW trend in and around high-angle fault of NS or NW trend. This study focused on deformation history of the Okcheon Supergroup, suggesting that the geological structure was formed at least by four phases of deformation. (1) The first phase of deformation occurred under ductile shear deformation of top-to-the southeast movement, forming sheath fold or A-type fold, asymmetric isoclinal fold, NW-SE trending stretching lineation. (2) The second phase of deformation took place under compression of NW-SE direction, forming subhorizontal, tight upright fold of M trend in the earlier phase, and formed semi-brittle thrust fault (Guryongsan Thrust Fault) of top-to-the southeast movement and associated snake-head fold in the later phase. (3) The third phase of deformation formed subhorizontal, open recumbent fold through gravitational or extensional collapses which might be generated from crustal thickening and gravitational instability. (4) The fourth phase of deformation formed moderately plunging, steeply inclined kink fold related to high-angle faulting, being closely connected with the local change of NE-trending regional foliation into NS to EW direction of strike in the vicinity of the high-angle fault.

The Relationship between the Anterior Cruciate Ligament Tear and the Posterior Cruciate Ligament Index on MRI Findings (자기공명영상 상 전방십자인대 파열과 후방십자인대 곡선값의 연관성)

  • Kang Jae Do;Kim Kwang Yul;Kim Hyung Cheon;Lee Sung Chun
    • Journal of the Korean Arthroscopy Society
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    • v.6 no.2
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    • pp.109-114
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    • 2002
  • Propose : The purpose of this retrospective study was to test the posterior cruciate ligament (PCL index) for diagnosis of a tear of the anterior cruciate ligament (ACL) by means of MR imaging. Materials and Methods : From Mar. 1997 to Feb. 2001, concomitant magnetic resonance imaging (MRI) and knee joint arthroscopy were performed in 56 patients of either pain or instability of the knee. The shortest distance between the femoral and tibial attachment of PCL (X) and the distance from that line to the tip of the arc marked by the PCL (Y) on the sagittal plane images were measured. The quotient of these two parameters (Y/X) defined the PCL index. Results : Using MRI diagnosis, there were 35 patients diagnosed with ACL rupture and 21 patients were ruled out of ACL injury. Using arthroscopy, 32 of the 35 patients diagnosed by MRI showed ACL rupture, and 20 of the 21 patients were ruled out of ACL injury. The mean PCL index was 0.40 in the 33 patients diagnosed with ACL rupture through arthroscopy. The mean PCL index was 0.23 in 23 patients with an uninjured ACL through arthroscopy. In 33 patients with ruptured ACL, this value exceeds 0.31. The index value was 0.31 in 3 patients with uninjured ACL. The value of the index was not above 0.31 with an uninjured ACL. PCL index on MRI had a sensitivity of $91\%$ and a specificity of $94\%$ for determining the status of the anterior cruciate ligament. Conclusion : Injury to the ACL changes the PCL index markedly. In diagnostically unreliable MR images, amelioration of the PCL index could help in the diagnosis of ACL injury.

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Outcome of Tumor Prosthetic Reconstruction in Osteosarcoma Patient (골육종 환자에서 종양 대치물을 이용한 재건술의 치료결과)

  • Kim, Jae-Do;Kim, Cheung-Kue;Chung, So-Hak
    • The Journal of the Korean bone and joint tumor society
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    • v.17 no.2
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    • pp.79-86
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    • 2011
  • Purpose: Modular tumor prosthesis is the most popular recontructive modality after resection of malignat tumor in extremity. Complications and survival of tumor prosthesis reconstruction are well-known. however, reports on the long-term outcome of tumor prosthesis in osteosarcoma patientss are scarece. Materials and Methods: In 158 cases as diagnosed as osteosarcoma from feburary 1989 to December 2006 in a single cancer center. We retrospectively reviewd 48 osteosarcoma patients who under went tumor prosthetic reconstruction. Mean follow up preiod was 75.6 months (range; 60 to 179 months). There were 28 males, 20 females and mean age was 22.4 years (range; 11-71). Pathologic subtypes were conventional central osteosarcoma in 46 cases and periosteal in 2 cases. The location of the tumor was proximal tibia (26 cases), distal femor (20 cases), femor diaphysis (1 case), and tibia diaphysis (1 case). In 41 cases built-up-type tumor prosthesis have been used and 7 cases expansion-type tumor prosthesis have been used. We used Musculoskeletal tumor society (MSTS) grading system to asses post operation function, and we analyzed survival rate of patient and tumor prosthesis and complication. Results: The overall survival rate was 77.7% and disease free survival rate was 68.9%. The survival rate of tumor prosthesis was 73%, in last follow up tumor prosthesis has been removed in 12 cases. All of them, 17 complications occurred, which included infection in 16 cases, Periprosthetic Fracture and Loosening of tumor prosthesis in 4 cases, articular instability in 4 cases. MSTS functional score was 74.1% in post operation. Conclusion: In long term follow up result, Primary tumor prosthesis -a reconstruction method after a wide extensional resecion of a bone tumor- can be a effective treatment method in asepect of survival rate, functional assesment and complication.