• Journal of the Korea Concrete Institute
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• v.11 no.6
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• pp.13-24
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• 1999

The external, unbonded prestressed concrete(PSC) members exhibit very different structural behavior from that of internal bonded PSC members because of eccentricity change and slip occurrence during loading process. The purpose of the present study is to propose the ultimate failure stresses of prestressing (PS) steels for those external unbonded PSC members. To this end, a comprehensive analysis has been made using the nonlinear finite element analysis program developed recently for external unbonded PSC members by authors. A series of major influencing variables have been included in the analysis. It was found that the span-depth ratio, neutral axis depth-effective depth ratio, load geometry, amount of ordinary steel, and prestressing steel ration have great influence for the ultimate failue stress of PS steel is preposed and is compared with experimental dat as well as existing formulas for internal unbonded members. The Comparison indicates that the proposed equation agrees relatively well with experimental data and that existing formulas including ACI and AASHTO equations show some discrepancies from experimental ones. The present study allows more realistic analysis and design of prestressed concrete structures with external unbonded tendons.

• Anatomy and Cell Biology
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• v.56 no.3
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• pp.328-333
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• 2023

The first extensor compartment of the wrist is a distinctly variable anatomical area. Anatomical variations in this region contribute to the pathophysiology and treatment failure of de Quervain's disease, which is a kind of tenosynovitis that develops in the first extensor compartment of the wrist. We aim to describe the first extensor compartment morphology, to evaluate the septum frequency, location of the septum, and the number of tendons of abductor pollicis longus (APL) and extensor pollicis brevis muscles (EPB). First extensor compartment of 87 wrists of 45 cadavers were dissected. The presence or absence of septum and number of tendon slips of APL and EPB revealed. The proximal and distal widths of the compartments were measured. Septums were detected in 60.9% (n=53) of the wrists. Incomplete (distal) and complete (proximal) septa were present in 35.6% (n=31) and 25.3% (n=22) of the cases. Only 26.4% of the wrists had a single slip of APL tendon. The Remaining had multiple slips. The median inner width of the proximal and distal compartments in all wrists were calculated as in the order of 9.11±1.14 mm and 8.55±1.12 mm. We believe that understanding the anatomy of the first extensor compartment in the Turkish population would be helpful to surgeons, radiologists, and physiotherapists to diagnose and manage de Quervain's disease.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.4A
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• pp.279-286
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• 2011

FRP (Fiber Reinforced Polymer) tendons can be used as an alternative to solve the corrosion problem of steel tendons. Material properties of FRP tendons-bond strength, transfer length, development length-must be determined in order to apply to concrete structures. First of all, in case of application for pretension concrete members with CFRP tendons, transfer length is an important characteristic. The bond of the material characteristics should be demanded clearly to apply to PSC structures prestressed with FRP tendons. This paper investigated on the bond characteristics of FRP reinforcements with various surface-type. To determine the bond characteristics of FRP materials used in place of steel reinforcement or prestressing tendon in concrete, pull-out testing suggested by CAN/CSA S806-02 was performed. A total of 40 specimens were made of concrete cube with steel strands, deformed steel bar and 6 different surface shape FRP materials like carbon or E-glass. Results of the bonding tests presented that each specimen showed various behaviors as the bond stress-slip curve and compared with the bond characteristic of CFRP tendon developed in Korea.

• Journal of the Korea institute for structural maintenance and inspection
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• v.6 no.3
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• pp.151-158
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• 2002

Recently, the externally prestressed unbonded steel I-beam bridges have been increasingly built. The mechanical behavior of prestressed steel I-beams which are with external unbonded tendon is different from that of normal bonded PSC beams in a point of that the slip of tendons at deviators and the change of tendon eccentricity occurs, when external loads are applied in external unbonded steel I-beams. The concept of prestressing steel structures has not been widely considered, in spite of long and successful history of prestressing concrete members. In this study, The field experiment on prestressed steel I-beams has been performed in the various aspects of prestressed I-beam including the tend on type and profile.

• Anatomy and Cell Biology
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• v.56 no.3
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• pp.398-400
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• 2023

The current case report describes an uncommon insertion of the levator scapulae (LS), which broadly attaches to multiple structures, including the serratus posterior superior, ligamentum nuchae, and the 6th and 7th spinous processes of the cervical vertebrae. The most superior portion of this aponeurosis merged with the ligamentum nuchae at the C7 level. The middle and inferior portions of the head were inserted (or fused) into the tendon of the rhomboid minor as well as the fibers of the serratus posterior superior muscle. Consequently, recognizing this anatomical variation, characterized by an additional slip of the LS attaching to the 7th vertebra and other muscular structures, is crucial not only for anatomists but also for surgeons performing procedures on the posterior neck related to cervical or shoulder pain and cervical dystonia.

• Journal of the Korean Geotechnical Society
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• v.25 no.10
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• pp.5-15
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• 2009

This paper presents the results of full-scale uplift load tests performed on 24 passive anchors grouted to various lengths at Okchun and Changnyong site. Rock anchors were installed over a wide range of rock types and qualities with a fixed anchored depth of 1~6 m. The majority of installations used D51 mm high grade steel rebar to induce rock failure prior to rod failure. However, a few installations included the use of D32 mm rebar at relatively deeper anchored depth so as to induce rod failure. In many tests, rock failure was reached and the ultimate loads were recorded along with observations of the shape and extent of the failure surface. In addition to field tests, laboratory pullout tests were conducted to determine bond strength and bond stress-shear slip relation at the tendon/grout interface when a corrosion protection sheath is installed in the cement-based grout. The test results show that the ultimate tendon-grout bond strength is measured from 18~25% of unconfined compressive strength of grout. One of the important results from these tests is that the measured strains along the corrosion protection sheath were so small that practically the reduction of bond strength by the presence of sheath would be negligible.

• Structural Engineering and Mechanics
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• v.50 no.5
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• pp.617-633
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• 2014

Because the elevated temperature degrades the mechanical properties of materials used in containments, the global behavior of containments subjected to the internal pressure under high temperature is remarkably different from that subjected to the internal pressure only. This paper concentrates on the nonlinear finite element analyses of the nuclear power plant containment structures, and the importance for the consideration of the elevated temperature effect has been emphasized because severe accident usually accompanies internal high pressure together with a high temperature increase. In addition to the consideration of nonlinear effects in the containment structure such as the tension stiffening and bond-slip effects, the change in material properties under elevated temperature is also taken into account. This paper, accordingly, focuses on the three-dimensional nonlinear analyses with thermal effects. Upon the comparison of experiment data with numerical results for the SNL 1/4 PCCV tested by internal pressure only, three-dimensional analyses for the same structure have been performed by considering internal pressure and temperature loadings designed for two kinds of severe accidents of Saturated Station Condition (SSC) and Station Black-out Scenario (SBO). Through the difference in the structural behavior of containment structures according to the addition of temperature loading, the importance of elevated temperature effect on the ultimate resisting capacity of PCCV has been emphasized.

• Journal of Korean Orthopaedic Sports Medicine
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• v.3 no.2
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• pp.134-140
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• 2004

Purpose: The reconstructive surgery of the anterior oblique ligament has been recommended for patients with unstable carpometacarpal joints. We reviewed retrospectively the functional results of two patients who had been treated by6 using a harvested portion of the tendon of flexor carpi radialis as a substitute for the anterior oblique ligament. Materials and Methods: In two patients with a instability of the trapeziometacarpal joint because of a rupture of the anterior oblique ligament, reconstruction was carried out using a slip of the tendon of flexor carpi radialis and the patients had been followed up for two years. Results: The results after a follow-up of two years that both of them had significant relief from pain and symptoms. The mean grip strength recovered to 90$\%$ of the controlateral side. patients felt that they had subjective improvement and would have undergone the operation again. Conclusion: Increased awareness of this lesion can lead to an early and clear diagnosis, so that the patient may be advised adequately.

• Journal of the Korean Arthroscopy Society
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• v.7 no.1
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• pp.92-95
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• 2003

A 34-year-old man with ACL total rupture due to slip down injury, had received ACL reconstruction using autogenous hamstrings tendon with cross-pin femoral fixation. Postoperative course was as usual. But postoperative 3 months later, he complained posterolateral knee pain, recurrent effusion and mild instability. He was managed repeatitive aspiration and nonsteroid antiinflammatory drugs but was failed to relieve symptoms & signs. In CT scans, perforation of posteromedial femoral cortex of lateral femoral condyle was found. In second look arthroscopy, two pieces of broken femoral cross pin were found in between tibiofemoral Joint which was badly injured cartilage. We considered malposition of pins was the main cause of failure. We propose that femoral tunnel must be made more acute angle and femoral cross-pin guide must be positioned more external rotation 10-20 degree than transepicondylar axis made confirm the cross-pin tunnel position in order to avoid posterior cortex perforation and early failure.