• Journal of the Semiconductor & Display Technology
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• v.22 no.4
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• pp.108-112
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• 2023

Precision manufacturing technology is rapidly developing due to the extreme miniaturization of semiconductor processes to comply with Moore's Law. Accurate and precise alignment, which is one of the key elements of the semiconductor pre-process and post-process, is very important in the semiconductor process. The center detection of wafer align marks plays a key role in improving yield by reducing defects and research on accurate detection methods for this is necessary. Methods for accurate alignment using traditional image sensors can cause problems due to changes in image brightness and noise. To solve this problem, engineers must go directly into the line and perform maintenance work. This paper emphasizes that the development of AI technology can provide innovative solutions in the semiconductor process as high-resolution image and image processing technology also develops. This study proposes a new wafer center detection method through variable thresholding. And this study introduces a method for detecting the center that is less sensitive to the brightness of LEDs by utilizing a high-performance object detection model such as YOLOv8 without relying on existing algorithms. Through this, we aim to enable precise wafer focus detection using artificial intelligence.

• Tribology and Lubricants
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• v.40 no.1
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• pp.24-27
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• 2024

A monotype valve body for a dual clutch transmission has the potential to reduce costs, weight, and manufacturing time by modularizing various parts, including those of existing solenoid packs and valve bodies, into one through the application of super-precision die casting technology. However, this approach may lead to challenges such as reduced rigidity and increased interference due to modularization and compactness, impacting both product performance due to the reduced weight as well as durability and reliability. Unlike existing products, this approach requires a high-precision thin-wall block to avoid more complicated flow line formation, interference between flow lines, and leaks, as well as a strict quality requirement standard and precise inspections including detection of internal defects. To conduct precise inspections, we built an equivalent model corresponding to a driving distance of 300,000 km. Testing involved simulating actual road loads using a real vehicle and a chassis dynamometer in the FTP-75 mode (EPA Federal Test Procedure). The aim of the study was to establish a vehicle load-based part durability model for manufacturing a mono-type valve body and to develop fundamental technology for part weight reduction through preliminary design by introducing analytical weight reduction technology based on the derived results.

• Journal of Embryo Transfer
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• v.18 no.3
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• pp.243-248
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• 2003

Sperrnatogenesis, the process by which the male germ-line stem cells(GSCs; type A spermatogonia) divide and differentiate to produce the mature spermatozoa, occurs in the seminiferous tubules of the testis. The GSCs proliferate actively to produce two types of cells: other GSCs and differentiating spermatogonia. GSCs have unipotentcy, devoted solely to the generation of sperm. The function of GSCs has broad implications for development, disease, and evolution. Spermatogenesis is fundamental for propagation of species and the defects of this system can result in infertility or disease. The ability to identify, isolate, culture, and alter GSCs will allow powerful new approaches in animal transgenesis and human gene therapy relating to infertility. Until recently, research on stem cells in the testis has been limited because of technical difficulties in isolating and identifying these cell populations. Here, we were trying to find out optimal conditions for in vitro culture of GSCs for identifying and isolating GSCs. We collected mouse GSCs from 3-days old mouse by two-step enzyme digestion method. GSCs were plated and grown on mouse embryonic fibroblasts in Dulbecco's modified Eagle's medium (DMEM) containing 15％ fatal bovine serum, 10 mM 2-mercaptoethanol, 1％ non-essential amino acids, 1 ng/$m\ell$ bFGF, 10 $\mu$M forskolin, 1500 U/$m\ell$ human recombinant leukemia inhibitory factor (LIF). Over a period 3∼5 days, GSCs gave rise to large multicellular colonies resembling those of mouse pluripotent stem cells. After 5th passages, cells within the colonies continued to be alkaline phosphatase and Oct-4 positive and tested positive against a panel of two immunological markers(Integrin $\alpha$ 6 and Integrin $\beta$ 1) that have been recognized generally to characterize GSCs. SSEA-1, SSEA-3, and SSEA-4 also showed positive signals. Based on our data, these GSCs-derived cultures meet the criteria for GSCs itself and even other pluripotent stem cells. We reported here the establishment of in vitro cultures from mouse male GSCs.

• Archives of Plastic Surgery
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• v.37 no.5
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• pp.712-716
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• 2010

Purpose: Extensive lumbosacral defects after removal of spinal tumors have a high risk of wound healing problems. Therefore it is an effective reconstructive strategy to provide preemptive soft tissue coverage at the time of initial spinal surgery, especially when there is an instrument exposure. For soft tissue reconstruction of a lumbosacral defect, a variation of the gluteal flap is the first-line choice. However, the musculocutaneous flap or muscle flap that is conventionally used, has many disadvantages. It damages gluteus muscle and causes functional disturbance in ambulation, has a short pedicle which limits areas of coverage, and can damage perforators, limiting further surgery that is usually necessary in spinal tumor patients. In this article, we present the superior gluteal artery perforator turn-over flap that reconstructs complex lumbosacral defects successfully, especially one that has instrument exposure, without damaging the ambulatory function of the patient. Methods: A 67 year old man presented with sacral sarcoma. Sacralectomy with L5 corpectomy was performed and resulted in a $15{\times}8\;cm$ sized complex soft tissue defect in the lumbosacral area. There was no defect in the skin. Sacral stabilization with alloplastic fibular bone graft and reconstruction plate was done and the instruments were exposed through the wound. A $18{\times}8\;cm$ sized superior gluteal artery perforator flap was designed based on the superior gluteal artery perforator and deepithelized. It was turned over 180 degrees into the lumbosacral dead space. Soft tissue from both sides of the wound was approximated over the flap and this provided in double padding over the instrument. Results: No complications such as hematoma, flap necrosis, or infection occurred. Until three months after the resection, functional disturbances in walking were not observed. The postoperative magnetic resonance imaging scan shows the flap volume was well maintained over the instrument. Conclusion: This superior gluteal artery perforator turn-over flap, a modification of the conventional superior gluteal artery perforator flap, is a simple method that enabled the successful reconstruction of a lumbosacral defect with instrument exposure without affecting ambulatory function.

• Journal of Korean Society of Steel Construction
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• v.28 no.5
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• pp.373-382
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• 2016

Painting or thermally sprayed metal coating is often used in corrosion protection of steel structures. In recently, duplex coating system which combines thermally sprayed metals with paint is selected as a new generic type of coatings on steel structures under the highly corrosive environments. In this study, the structural steel specimens were surface treated, thermally sprayed with zinc, zinc-15%aluminum alloy, aluminum and aluminum-5%magnesium alloy, and finally sealing or painted with acrylic urethane. And as a reference specimens, steel specimens were painted with acrylic urethane after surface treatment. Circular defects with 1.0, 3.0 and 5.0 mm in diameters and line defect with 2.0 mm width, which reach the steel substrate were created on all specimens. The specimens were exposed into an environmental testing chamber controlled by the ISO 20340, which is a laboratory cyclic accelerated exposure test condition of spraying/UV/low temperature, for up to 175 days. Based on the corrosion tests, corrosion deterioration from the initial defects were evaluated and weathering performance of the specimens are compared.

• Journal of the Korean earth science society
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• v.31 no.6
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• pp.563-572
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• 2010

Both multi-channel temperature monitoring and geophysical electric survey were performed together for an embankment to assess the leakage zone. Temperature variation according to space and time on the inner parts of engineering constructions (e.g.: dam and slope) can be basic information for diagnosing their safety problem. In general, as constructions become superannuated, structural deformation (e.g.: cracks and defects) could be generated by various factors. Seepage or leakage of water through the cracks or defects in old dams will directly cause temperature anomaly. This study shows that the position of seepage or leakage in dam body can be detected by multi-channel temperature monitoring using thermal line sensor. For that matter, diverse temperature monitoring experiments for a leakage physical model were performed in the laboratory. In field application of an old earth fill dam, temperature variations for water depth and for inner parts of boreholes located at downstream slope were measured. Temperature monitoring results for a long time at the bottom of downstream slope of the dam showed the possibility that temperature monitoring can provide the synthetic information about flowing path and quantity of seepage of leakage in dam body. Geophysical data by electrical method are also added to help interpret data.

• Journal of the Korean Chemical Society
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• v.27 no.4
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• pp.244-254
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• 1983

Single crystals of sodium thiosulfate $(Na_2S_2O_3) have been grown from the saturated solution by the evaporation method at the optimum condition. Radiation damages in the crystal by ${\gamma}$-irradiation of $20{\times}10^6$ Rontgen have given rise to paramagnetic centers. The anisotropic spectra of each paramagnetic species have been obtained with the X-band EPR spectrometer at room temperature. When an isotropic D.P.P.H. at g value of 2.0036 is based on. ESR Spectra of the single crystal are recorded for each rotation about the perpendicular a, b and c axis with intervals of $10^{\circ}$ from $0^{\circ}$to $180^{\circ}$ in order to find out the properties of the crystal for anglar variation of the anisotropic peaks. The g values are calculated from the line position between the anisotropic peaks and the isotropic peaks of D.P.P.H. and then principal g values and their direction cosines of the species is obtained by the diagonalization of 9 matrix elements of the corresponding g values. From the analysis of the characteristic principal g values and direction cosines for ${\gamma}$-irradiated $Na_2S_2O_3$ crystal, anisotropic peaks corresponding to $SO_2^+, SO_2^- $are identified and the existences of unidentified and unstable paramagnetic defects are verified.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.32 no.4
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• pp.360-373
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• 2006

The purpose of this research was to investigate whether pulsed electromagnetic field (PEMF) stimulation applied to the rabbit cranial defects grafted with ${\beta}$-tricalcium phosphate (${\beta}$-TCP) could affect the new bone formation. With 16 New Zealand white rabbits under the same condition, bilateral calvarial bone defects were formed around the sagittal suture line. The defect on the left side was grafted with ${\beta}$-TCP, while on the right side was grafted by harvested autogenous bone. PEMF was applied to 8 rabbits for 8 hours per day. The bony specimen were divided into 3 groups, the group 1 was autogenous bone grafted specimen, the group 2 was ${\beta}$-TCP grafted with PEMF, and the group 3 was ${\beta}$-TCP grafted without PEMF. We investigated the bone regeneration & growth factor expression at 2, 4, 6, and 8 weeks. As a result, BMP 2 was expressed in the group 1 from 2 weeks, the group 2 from 4 weeks, and the group 3 from 6 weeks. BMP 4 was expressed in the group 1 from 2 weeks, in the group 2 and the group 3 from 4 weeks. 4. There was no significant difference in expression pattern of BMP 7, PDGF, VEGF, and TGF-${\beta}$1 during grafted bone regeneration in group 1, 2, and 3. According to our results, PEMF stimulation could be effective on the new bome formation in animal study, and have a feasibility of clinical use.

• Molecules and Cells
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• v.43 no.3
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• pp.228-235
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• 2020

The Drosophila transmembrane semaphorin Sema-1a mediates forward and reverse signaling that plays an essential role in motor and central nervous system (CNS) axon pathfinding during embryonic neural development. Previous immunohistochemical analysis revealed that Sema-1a is expressed on most commissural and longitudinal axons in the CNS and five motor nerve branches in the peripheral nervous system (PNS). However, Sema-1a-mediated axon guidance function contributes significantly to both intersegmental nerve b (ISNb) and segmental nerve a (SNa), and slightly to ISNd and SNc, but not to ISN motor axon pathfinding. Here, we uncover three cis-regulatory elements (CREs), R34A03, R32H10, and R33F06, that robustly drove reporter expression in a large subset of neurons in the CNS. In the transgenic lines R34A03 and R32H10 reporter expression was consistently observed on both ISNb and SNa nerve branches, whereas in the line R33F06 reporter expression was irregularly detected on ISNb or SNa nerve branches in small subsets of abdominal hemisegments. Through complementation test with a Sema-1a loss-of-function allele, we found that neuronal expression of Sema-1a driven by each of R34A03 and R32H10 restores robustly the CNS and PNS motor axon guidance defects observed in Sema-1a homozygous mutants. However, when wild-type Sema-1a is expressed by R33F06 in Sema-1a mutants, the Sema-1a PNS axon guidance phenotypes are partially rescued while the Sema-1a CNS axon guidance defects are completely rescued. These results suggest that in a redundant manner, the CREs, R34A03, R32H10, and R33F06 govern the Sema-1a expression required for the axon guidance function of Sema-1a during embryonic neural development.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.25 no.1
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• pp.6-11
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• 1989

Some distinctive defects in the conventional stow net were examined and presented in the previous report of this series. To find out the more effective gear by correcting the defects, the authors carried out another experiment by using a newly designed gear. 1. Special features of the newly designed gear are: (1) stretched width of front end on top, bottom and side panel are decreased 20%, on the other hand, the frank of the panels are increased 10% compared with the conventional gear. Front end of top and bottom panels are bias cutten up to 20% of the length of panels. (2) Length of the head rope and ground rope are shortened 6% by changing of the shape of the top and bottom panels. (3) Lacing lines are attached to four longitudinal seaming lines with suitable hanging ratio. (4) Stretched height of the shearing device were shortened 17%, and the buoyancy on top of the device were increased 20%. (5) Length of the biforked pendants were arranged to be shorter on top-most and bottom-most ones, and loner on middle ones. 2. The observed result can be expressed as (1) Wrinkles in the front end of top panels are removed and fringe line of panels become smooth. (2) Opening height of mouth is observed 3% higher than that of the conventional gear. (3) Opening width is 1.5 to 1.6 times wider than that of the conventional gear. (4) Hydrodynamic resistance is decreased 10%-17%.