• Korean Journal of Veterinary Research
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• v.59 no.4
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• pp.175-180
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• 2019

This study was conducted to evaluate and analyze fractures types in wild mammals in Korea. Wild mammals treated at 3 wildlife centers in Korea were included. Of the 63 cases included in this study, water deer was the most common species encountered with fractures. We determined 85 different fracture sites, with maximum lumber vertebral fractures followed by femoral, tibial and pelvic fractures. External skeletal fixator (ESF)-intramedullary (IM) pin (IM+ESF tie-in fixation) was the most common method applied for the surgical treatment of mammals. Lumbar vertebrae and femur were the most common bones involved. The findings of this study are expected to provide information for veterinarians regarding the frequency and characteristics of fractures in wild mammals and serve as a basic database for the types and outcomes of fractures in wild mammals.

• New & Renewable Energy
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• v.2 no.3
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• pp.31-36
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• 2006

Superstrate pin amorphous silicon thin-film(a-Si:H) solar cells are prepared on $SnO_2:F$ and ZnO:Al transparent conducting oxides(TCO) in order to see the effect of TCO/p-layers on a-Si:H solar cell operation. The solar cells prepared on textured ZnO:Al have higher open circuit voltage VOC than cells prepared on $SnO_2:F$. Presence of thin microcrystalline p-type silicon layer(${\mu}c-Si:H$) between ZnO:Al and p a-SiC:H plays a major role by causing improvement in fill factor as well as $V_{OC}$ of a-Si:H solar cells prepared on ZnO:Al TCO. Without any treatment of pi interface, we could obtain high $V_{OC}$ of 994mV while keeping fill factor(72.7%) and short circuit current density $J_{SC}$ at the same level as for the cells on $SnO_2:F$ TCO. This high $V_{OC}$ value can be attributed to modification in the current transport in this region due to creation of a potential barrier.

• Journal of the Korean Ceramic Society
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• v.34 no.10
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• pp.1021-1026
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• 1997

RuO2 thin film has reasonably good conductivity and stiffness and it is thought to substitute for the cantilever beam made up of Pt and Si3N4 double layers in microactuators. Therefore, anisotopic Si etching was performed using RuO2 thin film as a mask layer in 25 wt. % TMAH water solution. In the etching temperature ranging from 6$0^{\circ}C$ to 75$^{\circ}C$, the etch rates of all the crystallographic directions increased linearly as the etching temperature increased. The etch rate ratio(selectivity) of [111]/[100] which varied from 0.08 to 0.14, was not sensitive to temperature. The activation energies for [110] direction, [100] direction and [111] direction were 0.50, 0.66 and 1.04eV, respectively. RuO2 cantilever beam with a clean surface was formed at the etching temperatures of 6$0^{\circ}C$ and $65^{\circ}C$. But the damages due to formation of pin holes on RuO2 surface were observed beyond 7$0^{\circ}C$. The tensile stress of RuO2 thin films caused the cantilever bending upward. As a result, it was demonstrated that the formation of conducting oxide RuO2 cantilever beam which can replace the role of an electrode and supporting layer could be possible by TMAH solution.

• Journal of Welding and Joining
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• v.16 no.4
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• pp.92-97
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• 1998

Because of the low melting temperature of solder, each temperature cycle initiates an irrecoverable creep deformation at the solder interconnection which connects the package body with the PCB. The crack starts and propagates from the position where the creep deformation is maximized. This work has tried to compare and analyze the thermal fatigue life of solder interconnection which is affected by the lead material, the size of die pad, chip thickness, and interface delamination of 48-Pin TSOP under the temperature cycle ($0^{\circ}C$~1$25^{\circ}C$). The crack initiation position and thermal fatigue life which are calculated by using FEA method are well matched with the results of experiments. The thermal Fatigue life of copper lead frame is extended around 3.6 times longer than that of alloy 42 lead frame. It is maximized when the chip size is matched with the length of the lead. It tends to be extended as the thickness of chip got thinner. As the interfacial delamination between die pad and EMC is increased, the thermal fatigue life tends to decrease in the beginning of delamination, and increase after the delamination grew after 45% of the length of die pad.

• Korean Journal of Materials Research
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• v.25 no.7
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• pp.322-329
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• 2015

The magnitude of wear should be at a minimum for numerous automobile and aeronautical components. In the current work, composites were prepared by varying the cenosphere content using the conventional stir casting method. A uniform distribution of particles was ensured with the help of scanning electron microscopy (SEM). Three major parameters were chosen from various factors that affect the wear. A wear test was conducted with a pin-on-disc apparatus; the controlling parameters were volume percentages of reinforcement of 5, 10, 15, and 20%, applied loads of 9.8, 29.42, and 49.03 N, and sliding speeds of 1.26, 2.51, and 3.77 m/s. The design of the experiments (DOE) was performed by varying the different influencing parameters using the full factorial method. An analysis of variance (ANOVA) was used to analyze the effects of the parameters on the wear rate. Using regression analysis, a response curve was obtained based on the experimental results. The parameters in the resulting curve were optimized using the Genetic Algorithm (GA). The GA results were compared with those of an alternate efficient algorithm called Neural Networks (NNs).

• Nuclear Engineering and Technology
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• v.30 no.4
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• pp.342-352
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• 1998

A nuclear design feasibility of soluble boron free(SBF core for the medium-sized(600MWe) PWR was investigated. The result conformed that soluble boron free operation could be performed by using current PWR proven technologies. Westinghouse advanced reactor, AP-600 was chosen as a design prototype. Design modification was applied for the assembly design with burnable poison and control rod absorber material. In order to control excess reactivity, large amount of gadolinia integral burnable poison rods were used and B4C was used as a control rod absorber material. For control of bottom shift axial power shape due to high temperature feedback in SBF core, axial zoning of burnable poison was applied to the fuel assemblies design. The combination of enrichment and rod number zoning for burnable poison could make an excess reactivity swing flat within around 1% and these also led effective control on axial power offset and peak pin power, The safety assessment of the designed core was peformed by the calculation of MTC, FTC and shutdown margin. MTC in designed SBF core was greater around 6 times than one of Ulchin unit 3&4. Utilization of enriched BIO(up to 50w1o) in B4C shutdown control rods provided enough shutdown margin as well as subcriticality at cold refueling condition.

• Journal of Korea Foundry Society
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• v.26 no.4
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• pp.174-179
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• 2006

This study aims to investigate the microstructures and mechanical properties of DCI manufactured by sand and metal mold casting. To prohibit the formation of the chill, carbon, silicon and rare earth($0{\sim}0.2\;wt%$) were controlled and temperature of metal mold was constantly kept at $160^{\circ}C$. The sizes, counts and nodularity ratios of nodules were analyzed by image analysis device. Wear test using pin-on-disc wear tester was carried out under the conditions of load 47.2N, velocity 0.4 m/s and distance 2000 m. Tensile test using Instron type testing machine was performed with velocity of 0.1 mm/min according to the KS B 0802. The formation of the chill was not observed when percentage of the carbon and silicon were 3.8 and 2.5. Mechanical properties of GCD manufactured by metal mold were better than sand casting.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.2 s.257
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• pp.197-204
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• 2007

Fretting is a contact damage process that occurs between two contact surfaces. Fretting fatigue reduces fatigue strength of the material due to low amplitude oscillatory sliding and changes in the contact surfaces of strongly connected machine and structure such as bolt, key, pin, fixed rivet and connected shaft, which have relative slip of repeatedly extreme low frequency amplitude. In this research, the fretting fatigue behavior of 2024-T3511 and 7050-T7451 aluminum alloys used mainly in aircraft and automobile industry were experimentally estimated. Based on this experimental wort the following results were obtained: (1) A significant decrease of fatigue lift was observed in the fretting fatigue compared to the plain fatigue. The fatigue limit of 2024-T3511 aluminum alloy decreased about 59% while 7050-T7451 aluminum alloy decreased about 75%. (2) In 7050-T7451 specimen using ATSI4030 contact pad, crack was initiated more early stage than using 2024-T3511 contact pad. (3) In all specimens, oblique cracks were initiated at contact edge. (4) Tire tracks and rubbed scars were observed in the oblique crack region of fracture surface.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2002.11a
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• pp.21-26
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• 2002

Solder flip chip bumping and subsequent coining processes on PCB were investigated to solve the warpage problem of organic substrates for high pin count flip chip assembly by providing good co-planarity. Coining of solder bumps on PCB has been successfully demonstrated using a modified tension/compression tester with height, coining rate and coining temperature variables. It was observed that applied loads as a function of coined height showed three stages as coining deformation : (1) elastic deformation at early stage, (2) linear increase of applied load, and (3) rapid increase of applied load. In order to reduce applied loads for coining solder bumps on PCB, effects of coining process parameters were investigated. Coining loads for solder bump deformation strongly depended on coining rates and coining temperatures. As coining rates decreased and process temperature increased, coining loads decreased. Among the effect of two factors on coining loads, it was found that process temperature had more significant effect to reduce applied coining loads during the coining process. Lower coining loads were needed to prevent substrate damages such as micro-via failure and build-up dielectric layer thickness change during applying loads. For flip chip assembly, 97Pb/Sn flip chip bumped devices were successfully assembled on organic substrates with 37Pb/Sn coined flip chip bumps.

• Journal of Veterinary Clinics
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• v.25 no.6
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• pp.545-548
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• 2008

A 3-year-old castrated male Siberian husky was presented for evaluation after being hit by a car. On physical examination, the dog showed open-mouth, displacement of mandible and hypersalivation with blood ting. The base of tongue was transected almost 80% on the bias from right dorsal side to the left ventral side. Radiography demonstrated separation of mandible symphysis, and fracture of right condyle and vertical ramus. After debridement of the necrotic tissue, tongue apposition with simple interrupted suture was performed. Mandibular symphysis, condyle and mandibular vertical ramus fractures were fixed using pin, cerclage wire, T-plate, and K-wires. The mouth was irrigated daily using chlorhexidine after surgery. The sutures that were loose here or untied at tongue were re-sutured under sedation. The transected tongue was healed and recovered its normal movement after 6 weeks.