• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1368-1372
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• 2003

PMMA which is used as the bone cement for vertebroplasty is able to be a supporter, as a fixing supporter role, for broken trabecular structure, caused by the compressed fracture of spine on aged osteoporosis. In this thesis, as experimenting apparent density of bone pieces, we have figured out support extent of Young's modulus as classifying the bone pieces injected PMMA and the others which are not. In case of low apparent density of PMMA in some bone, Young's modulus seems to be more supportable to bone. On the other hand, if apparent density of bones is normal, injection of PMMA is not very effective on improvement in Young's modulus of bone cement injection.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.494-504
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• 2008

Successful design, construction and maintenance of NATM tunnel demands prediction, control, stability estimation and monitoring of surface settlement, gradient and ground displacement with high accuracy. Back analysis using measured data and forward analysis have been and are indispensable tools to achieve this goal. Sakurai provided the hazard warning levels for assessing the stability of tunnels using the relation of critical strain and apparent Young's modulus. This paper performed the estimation of tunnel stability on construction. Firstly, the apparent Young's modulus concept and back analysis method is introduced for the assessment of tunnel safety during excavation a brief framework. Secondly, this paper deals with case study using "Apparent Young's modulus" and "Back analysis" for the purpose of estimating the stability of NATM tunnel in Korea. Finally, a general method that can be estimated the tunnel stability discussed by a flow chart.

• Journal of Biomedical Engineering Research
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• v.22 no.5
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• pp.419-424
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• 2001

We intended to evaluate the Young's modulus of trabecular bone of a human distal femur by spherical Indentation test and CT images and to quantify relationships between the direction of load, density. and Young's modulus. The specimens were scanned at 1 mm intervals on CT scanner After scanning the bones were sectioned with diamond saw. producing 8mm cubes of trabecular bone. The tubes were mechanically tested in inferior-superior(IS), anterior-posterior(AP). and medial-lateral(ML) direction with custom-made device. After testing, the real apparent density of specimens were measured. The results of this study showed that the IS modulus was significant1y greater than both the AP and ML modulus and the AP modulus was also greater than ML modulus significantly(p〈0.01) A significant Power relationship between the apparent density and the modulus was also found.

• Journal of Biomedical Engineering Research
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• v.24 no.4
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• pp.369-373
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• 2003

The compressed fracture of spine caused by osteoporosis is one of the most frequent diseases in bone fracture. Recently the vertebroplasty has drawn much attention as a medical treatment for the compressed fracture of spine, which strengthens the vertebral body and corrects deformity, and relieves pain in patients by injecting bone cement. But because there were no research about strengthening of mechanical properties of verbral body in bone cement injection, in this study, based on the properties of PMMA, we had measured the Young's modulus for different apparent densities of intact trabecular bone and PMMA injected one from a porcine and a cadaver. Young's modulus to apparent density had a form of a power series in intact trabecular bone and had a linear relation in PMMA injected bone.

• Journal of Sericultural and Entomological Science
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• v.14 no.1
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• pp.43-47
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• 1972

The tensile properties of cocoon filament obtained from the dried cocoon were studied by deniroscope and tensilon with special attachments. The strength and dried elongation at break feint with dry and swollen samples were observed. The apparent young's modulus was also calculated with the dry samples. The results obtained are as follows. 1) The breaking strength of dry and swollen samples decreased in parallel with denier decreasing ratio in the whole length of a cocoon filament. 2) Tensile strength of inner-layer filament, when treated at the temperature of 95$^{\circ}C$ for 15 min., was 37 per cent of outer-layer filament. 3) By swelling treatment, the breaking strength of the filament was decreased but the elongation was increased. 4) Apparent young's modulus and tensile strength per denier of inner-layer filament were higher than those of the rest cocoon layer.

• Geomechanics and Engineering
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• v.22 no.4
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• pp.277-290
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• 2020

This paper presents an elastic-plastic solution for the circular tunnel of elastic-strain softening behavior considering the pressure-dependent Young's modulus and the nonlinear dilatancy. The proposed solution is verified by the results of the field measuring and numerical simulation from a practical project, and a published closed-form analysis solution. The influence of each factor is discussed in detail, and the ability of Young's modulus and dilatancy characterizing the mechanical response of surrounding rock is investigated. It is found that, in low levels of support pressure, adopting the constant Young's modulus model will seriously misestimate the surrounding rock deformation. Using the constant dilatancy model will underestimate the surrounding rock deformation. When adopting the constant dilatancy model, as the dilation angle increases, the range of the plastic region increases, and the surrounding rock deformation weakens. When adopting the nonlinear dilatancy, the plastic region range and the surrounding rock deformation are the largest. The surrounding rock deformation using pressure-dependent Young's modulus model is between those resulted from two constant Young's modulus models. The constant α of pressuredependent Young's modulus model is the main factor affecting the tunnel displacement. The influence of α using a constant dilatancy model is much more apparent than that using a nonlinear dilatancy model.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1336-1340
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• 2003

The compressed fracture of spine caused by osteoporosis is one of the most frequent diseases in bone fracture. Recently the vertebroplasty has drawn much attention as a medical treatment for the compressed fracture of spine, which strengthens the vertebral body and corrects deformity, and relieves pain in patients by injecting bone cement. The purpose of this research is to provide the theoretical background for the vertebroplasty by employing scientific methods and thus to find out the improvements of the conventional surgical method. By applying the engineering analysis tools to clinical study, new application fields can also be obtained

• Journal of the Korean Wood Science and Technology
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• v.43 no.2
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• pp.177-185
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• 2015

The goal of this study is to evaluate the limitation of ASTM D 198 bending and ASTM D 3044 in determination of elastic modulus and shear modulus. Different material properties and span to depth ratios were used to analyze the effects of material property and testing conditions. The ratio of true elastic modulus to apparent elastic modulus evaluated from ASTM D 198 bending sharply decreased with increment of span to depth ratio. Shear modulus evaluated from ASTM D 198 bending decreased with increment of depth, whereas shear modulus evaluated from ASTM D 3044 was hardly influenced by increment of depth. Poisson's ratio influenced shear modulus from ASTM D 198 bending but did not influence shear modulus from ASTM D 3044. Different shearing factor was obtained for different depths of beams to correct shear modulus obtained from ASTM D 198 bending equivalent to shear modulus from theory of elasticity. Equivalent shear modulus of materials could be obtained by applying different shearing factors associated with beam depth for ASTM D 198 bending and correction factor for ASTM D 3044.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.170-180
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• 2008

Successful design, construction and maintenance of NATM tunnel demands prediction, control, stability guidelines, the estimation pre-improvement support system and monitoring of surface settlement, gradient and ground displacement with high accuracy. Moreover, urban NATM tunnel under difficult geotechnical conditions is important the estimation and necessary of pre-improvement support system. Various strategies have been proposed for the quantitative estimation of pre-improvement support system. This paper was investigated and analysed an assessment technique for the quantitative estimation of pre-improvement support system on underground space, as mountain and urban tunnel, in detail. The analysis performed on design and construction stage with field database using the proposed stability estimation index by many researcher including the critical strain and the apparent Young's modulus concept.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.2
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• pp.349-356
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• 2002

For two kinds of 25Cr-20Ni stainless steels, STS310J1TB and STS310S with and without a small amount of Nb and N, creep behavior has been studied in a stress and temperature range from 147 to 392 MPa and from 923 to 773 K with a special reference to tertiary creep. The average creep life of STS310J1TB was about 100 times longer than that of the STS310S. The apparent activation energy for the initial creep rate was 330 kJ/mol in STS310J1TB, while that of the STS310S was 274kJ/mol in a power law creep region and 478 kJ/mol in a region of power law breakdown (PLB). The activation energy for STS310S below PLB is close to the for self-diffusion. When compensating for the temperature dependence of the Young's modulus and the omega value, it was found that the apparent activation energy for STS310J1TB was reduced to the activation energy for diffusion of chromium atom in gamma steel. The stress exponent of STS310S was about 12.3 above PLB and 5.1 in a power law creep region. Notwithstanding that the creep condition for STS310J1TB was in a power law creep region, its stress exponent was 7.9 larger than that of STS310S corresponding to the same creep conditions. This was ascribed to the presence of fine precipitates in STS310J1TB.