• International Journal of Concrete Structures and Materials
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• v.10 no.1
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• pp.75-85
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• 2016

Fire ranks high among the potential risks faced by most buildings and structures. A full understanding of temperature effects on fiber reinforced concrete is still lacking. This investigation focuses on the study of the residual compressive strength, stress strain behavior and surface cracking of structural polypropylene fiber-reinforced concrete subjected to temperatures up to $300^{\circ}C$. A total of 48 cubes was cast with different fiber dosages and tested under compression after exposing to different temperatures. Concrete cubes with varying macro (structural) fiber dosages were exposed to different temperatures and tested to observe the stress-strain behavior. Digital image correlation, an advanced non-contacting method was used for measuring the strain. Trends in the relative residual strengths with respect to different fiber dosages indicate an improvement up to 15 % in the ultimate compressive strengths at all exposure temperatures. The stress-strain curves show an improvement in post peak behavior with increasing fiber dosage at all exposure temperatures considered in this study.

• Transactions of Materials Processing
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• v.25 no.2
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• pp.91-95
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• 2016

This paper is concerned with modeling of a ductile fracture criterion for sheet metal considering anisotropy to predict the sudden fracture of advanced high strength steel (AHSS) sheets during complicated forming processes. The Lou−Huh ductile fracture criterion is modified using the Hill’s 48 anisotropic plastic potential instead of the von Mises isotropic plastic potential to take account of the influence of anisotropy on the equivalent plastic strain at the onset of fracture. To determine the coefficients of the model proposed, a two dimensional digital image correlation (2D-DIC) method is utilized to measure the strain histories on the surface of three different types of specimens during deformation. For the derivation of an anisotropic ductile fracture model, principal stresses (𝜎₁,𝜎₂, 𝜎₃) are expressed in terms of the stress triaxiality, the Lode parameter, and the equivalent stress (𝜂_𝐻, 𝐿,) based on the Hill’s 48 anisotropic plastic potential. The proposed anisotropic ductile fracture criterion was quantitatively evaluated according to various directions of the maximum principal stress. Fracture forming limit diagrams were also constructed to evaluate the forming limit in sheet metal forming of AHSS sheets over a wide range of loading conditions.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.435-437
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• 2003

In order to investigate processes and factors controlling the chemical and isotopic compositions of the Han River, seasonal studies were carried out. The North Han River was much lower in the concentrations of total dissolved solids (TDS), dissolved inorganic carbon (DIC) and major ions than the South Han River, but higher in $SiO_2$ concentration, $\delta$$^{34}$ $S_{so4}$ value and $^{87}$ Sr/$^{86}$ Sr ratio. This indicates that the chemical and isotopic compositions of the Han River were strongly controlled by the geology of their drainage basins: silicate rocks in the North Han River and carbonate rocks in the South Han River. The $\delta$$^{34}$ $S_{so4}$ values were relatively higher in the North Han River (5.90$\pm$1.46$\textperthousand$)) than in the South Han River (3.48$\pm$0.73$\textperthousand$). This implies that dissolved S $O_{4}$$^{2-}$ in the North Han River might be mostly derived from deposition of atmospheric sulfates, whereas in the South Han River from oxidation of sulfide minerals in the abandoned poly-metallic deposits and the coal-bearing sedimentary rocks distributed over the upstream as well as deposition of atmospheric sulfates. The $^{87}$ S $r^{86}$ Sr ratios in the North Han River were distinctly higher than those in the South Han River, reflecting water-rock interaction with different rock types.pes.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.45-48
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• 2008

The mechanical behavior of small-sized materials has been investigated for many industrial applications, including MEMS and semiconductors. It is challenging to obtain accurate mechanical properties measurements for thin films due to several technical difficulties, including measurement of strain, specimen alignment, and fabrication. In this work, we used the micro-tensile testing unit with the real-time DIC (Digital Image Correlation) strain measurement system. This system has advantages of real time strain monitoring up to 50 nm resolution during the micro-tensile test, and ability to measure the young's modulus and Poisson's ratio at the same time. The mechanical properties of SCS (Single Crystal Silicon) are measured by uniaxial tension test from freestanding SCS which are $2.5{\mu}m$ thick, $200-500{\mu}m$ wide specimens on the (100) plane. Young's modulus, Poisson's ratio and tensile strength in the <110> direction are measured by micro-tensile testing system.

• Journal of Computing Science and Engineering
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• v.11 no.3
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• pp.79-91
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• 2017

In this paper, the abdominal-deformation measurement scheme is conducted on a shape-flexible mannequin using the DIC technique in a stereo-vision system. Firstly, during the integer-pixel displacement search, a novel fractal dimension based on an adaptive-ellipse subset area is developed to track an integer pixel between the reference and deformed images. Secondly, at the subpixel registration, a new mutual-learning adaptive particle swarm optimization (MLADPSO) algorithm is employed to locate the subpixel precisely. Dynamic adjustments of the particle flight velocities that are according to the deformation extent of each interest point are utilized for enhancing the accuracy of the subpixel registration. A test is performed on the abdominal-deformation measurement of the shape-flexible mannequin. The experiment results indicate that under the guarantee of its measurement accuracy without the cause of any loss, the time-consumption of the proposed scheme is significantly more efficient than that of the conventional method, particularly in the case of a large number of interest points.

• Asian-Australasian Journal of Animal Sciences
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• v.4 no.1
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• pp.73-78
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• 1991

Sixty-one 5-11 month-old California, Chinchilla and New Zealand White rabbit were employed in this investigation. Thirty-three does were superovulated by injecting FSH/HCG subcutaneously or intravenously and then sacrificed at different hours after mating. The ova were collected from the fallopian tubes with Ham's F-10 medium supplemented with 0.4% bovine serum albumin (BSA) and 1% pregnant rabbit serum (PRS). Embryos were examined under an inverted DIC microscopy for observing the stage of development. We have found that the fertilized ova formed pronuclei at 19 - 20 hr postcoitus. Approximately at 26, 64 - 78 and 84 - 88 hr after mating, the fertilized ova cleaved further to 2-cell, morulae and blastocyst stage respectively. Another 28 does were allocated to the gene transfer study. Fourteen of the 28 does were sacrificed at 19 - 20 hr to donate the pronuclear stage ova for gene injection. The other 14 does were induced to pseudopreganacy by injection of 100 IU HCG intravenous as recipients. Four hundreds and seventeen ova were injected totally and 212 gene injected zygotes were transferred into the recipient oviducts. Five recipients became pregnant and 10 fetuses were obtained. Eight of the 10 fetuses were analysed for gene incorporation, but none of them were transgenic.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.5
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• pp.515-520
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• 2004

We report on the development of a Piezoelectric valvc that is designed to have a high reliability for fluid control systems, such as mass flow control, transportation and chemical analysis. The valve was fabricated using a MCA(multilayer ceramic actuator), which has a low consumption power, high resolution and accurate control. The fabricated valve is composed of MCA, a valve actuator die and an seat die. The design of the actuator dic was done by FEM(finite element method) modeling, respectively. And, the valve seat die with 6 trenches was made. and the actuator die, which possible to optimize control to MCA, was fabricated. After Si-wafer direct bonding between the seat die and the actuator die, MCA was also anodic bonded to the scat/actuator die structure. PDMS(poly dimethylsiloxane) sealing pad was fabricated to minimize a leak-rate. It was also bonded to scat die and stainless steel package. The flow rate was 9.13 sccm at a supplied voltage of 100 V with a 50 % duty ratio and non-linearity was 2.24 % FS. From these results, the fabricated MCA valve is suitable for a variety of flow control equipments, a medical bio-system, semiconductor fabrication process, automobile and air transportation industry with low cost, batch recess and mass production.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.200-201
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• 2017

This paper introduces the SPICE simulation results of 3D sequential inverter considering electrical coupling. TCAD data and the SPICE data are compared to verify that the electrical coupling is well considered by using BSIM-IMG for the upper NMOS and LETI-UTSOI model for the lower PMOS. When inter layer dielectric is small, it is confirmed that electrical coupling is well reflected in the top transistor $I_{ds}-V_{gs}$ characteristics according to the change of the bottom transistor gate voltage.

• Geomechanics and Engineering
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• v.5 no.6
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• pp.499-517
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• 2013

In order to investigate shear behavior of granular materials due to excavation and associated unloading actions, load-controlled plane strain compression tests under decreasing confining pressure were performed under drained conditions and the results were compared with the conventional plane strain compression tests. Four types of granular material consisting of two quartz sands and two glass beads were used to investigate particle shape effects. It is clarified that macro stress-strain behavior is more easily influenced by stress level and stress path in sands than in glass beads. Development of localized deformation was analyzed using photogrammetry method. It was found that shear bands are generated before peak strength and shear band patterns vary during the whole shearing process. Under the same test condition, shear band thickness in the two sands was smaller than that in one type of glass beads even if the materials have almost the same mean particle size. Shear band thickness also decreased with increase of confining pressure regardless of particle shape or size. Local maximum shear strain inside shear band grew approximately linearly with global axial strain from onset of shear band to the end of softening. The growth rate is found related to shear band thickness. The wider shear band, the relatively lower the growth rate. Finally, observed shear band inclination angles were compared with classical Coulomb and Roscoe solutions and different results were found for sands and glass beads.

• Journal of Chest Surgery
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• v.25 no.7
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• pp.769-776
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• 1992

Total 632 cases of open heart surgery were performed in the department of thoracic and cardiovascular surgery, Pusan Paik Hospital, Inje University from october 1985 to december 1990. Among them, there were 503 cases of congenital heart disease and 129 cases of acquired heart disease. In the cases of 503 congenital heart disease surgically corrected, 122 cases over 15 years of age were reviewed and its results were summarized as follows ; l. In total 122 cases 65 were male and 52 female. 2. There were 54 patients under 20 years of age, 31 between 20 & 24 years, 20 between 25 & 29 and 17 over 30 years of age. The eldest was a 46-year-old female of atrial septal defect group. 3. There were 63 cases of VSD[51.7%], 38 of ASD[31.2%], 11 cases of TOF[9%] and so on. 4. In recovery cases, main post-operative complications were as follows; cardiac tamponade, arrhythmia, low cardiac output syndrome, pulmonary, edema pericarditis, mediastinitis, sepsis and DIC. 5. There were 3 cases of post-operative death in this series, so operative mortality rate was 2.5% compairing with 1.8% of pediatric cases below 15 years of age. 6. This reviewed series reveal that aggressive surgical approach in adult congenital heart disease can be justified with low operative mortality like as pediatric age group.