• Architectural research
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• 제23권1호
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• pp.11-17
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• 2021

A concrete-filled circular steel tube beam was fabricated, and a bending test was performed to analyze its failure modes, displacement ductility, bending-shear strength, and load-central deflection relationship. For the bending test, the installation position of the shape memory alloy (SMA) inside and outside the double-skin steel tube was used, and the rebar installation position, the concrete strength, the mixing of fibers, and the inner-outer diameter ratio as the main parameters. The test results showed that the installation positions of the reinforcements inside and outside the double-skin steel tube and the inner-outer diameter ratio of the steel tube affected the ductility, maximum load, and failure mode. In general, the specimen made of general concrete with SMA installed outside and inside (OI) the double-skin steel tube showed the best results.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.707-710
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• 2009

As the inner diameter of CCFL is increased in the range of outer diameters 3~5 mm, the luminance efficiency is increased by the low power consumption. For the outer diameter 5 mm, the efficiency is linearly increased even at the range of a high current.

• Asian Journal of Atmospheric Environment
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• 제11권2호
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• pp.131-137
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• 2017

A cyclone is an effective tool to facilitate the collection of aerosol particles without using filters, and in cell exposure studies is able to collect a sufficient amount of aerosol particles to evaluate their adverse health effect. In this study, we examined two different methods to improve the aerosol particle collection efficiency of a cyclone. The individual and combined effects of reducing the surface roughness of the inner wall of the cyclone and of using a circular cone attachment were tested. The collection efficiency of particles of diameter $0.2{\mu}m$ was improved by approximately 10% when using a cyclone with a smoothened inner wall (average roughness $Ra=0.08{\mu}m$) compared with the original cyclone ($Ra=5.1{\mu}m$). A circular cone attachment placed between the bottom section of the cyclone and the top section of a collection bottle, resulted in improved collection of smaller particles without the attachment. The 50% cutoff diameter of the modified cyclone (combined use of smoothened inner wall and attachment) was $0.23{\mu}m$ compared to $0.28{\mu}m$ in the original model. The combined use of these two techniques resulted in improved collection efficiency of aerosol particles.

• 전기학회논문지
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• 제61권7호
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• pp.988-991
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• 2012

The computer simulation was performed to confirm distribution of current and power density according to inner diameter of graphite mold of SPS(Spark Plasma Sintering). When the inner diameters of a graphite mold are varied $10mm{\Phi}$, $20mm{\Phi}$, $30mm{\Phi}$ and $40mm{\Phi}$, the more the inner diameter of graphite mold is decreased, the more the current density of punch section is increased. Because the electrical resistivity of the SiC-$ZrB_2$ specimen section($7.77{\times}10^{-4}{\Omega}{\cdot}cm$) was lower than the electrical resistivity($6.00{\times}10^{-3}{\Omega}{\cdot}cm$) of graphite section, the current density and power density of specimen section was higher than those of graphite section. It is considered that a SiC-$ZrB_2$ composite is sintered by more Joule heat of specimen section than that of mold and punch section. The current and power density distribution of a SiC-$ZrB_2$ composite can be predicted through computer simulation when SPS is conducted, and an electrical resistivity of the SiC-$ZrB_2$ composite is main element of SPS.

• Structural Engineering and Mechanics
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• 제87권2호
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• pp.137-149
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• 2023

In this study, to explore the working performance of the CFST split spherical node wind power tower, two groups of CFST split spherical joint plane towers with different web wall thicknesses and a set of space systems were analyzed. The tower was subjected to a low-cycle repeated load test, and the hysteresis and skeleton curves were analyzed. ABAQUS finite element simulation was used for verification and comparison, and on this basis parameter expansion analysis was carried out. The results show that the failure mode of the wind power tower was divided into weld tear damage between belly bar, high strength bolt thread damage and belly rod flexion damage. In addition, increasing the wall thickness of the web member could render the hysteresis curve fuller. Finally, the bearing capacity of the separated spherical node wind power tower was high, but its plastic deformation ability was poor. The ultimate bearing capacity and ductility coefficient of the simulated specimens are positively correlated with web diameter ratio and web column stiffness ratio. When the diameter ratio of the web member was greater than 0.13, or the stiffness ratio γ of the web member to the column was greater than 0.022, the increase of the ultimate bearing capacity and ductility coefficient decreased significantly. In order to maximize the overall mechanical performance of the tower and improve its economy, it was suggested that the diameter ratio of the ventral rod be 0.11-0.13, while the stiffness ratio γ should be 0.02-0.022.

• 대한수의학회지
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• 제37권2호
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• pp.445-450
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• 1997

The purpose of this study is to determine the changes of ultrasonographic appearance of stomach, pylorus and duodenum in relation to food intake and administration of contrast medium in dogs. Ultrasonograms were obtained with 5.0MHz sector transducer. After placing the dogs in dorsal recumbency, scanning was performed at the 8th intercostal space. The mean inner diameter of stomach immediately after food intake, 2, 4 and 6 hours was 47.9, 51.5, 46.8 and 40.6mm, respectively. The diameter of pylorus immediately after food intake, 2, 4 and 6 hours was 7.4, 9.7, 8.9 and 6.0mm, respectively(p<0.01). The diameter of duodenum immediately after food intake 2, 4 and 6 hours was 12.5, 7.9, 11.9 and 11.8mm, respectively(p<0.01). Before administration of contrast medium, the mean inner diameter of stomach, pylorus and duodenum was 38.6, 7.2 and 9.5mm, respectively. After administration of contrast medium, the diameters of stomach, pylorus and duodenum was 42.8, 7.7 and 9.9mm, respectively. It may be concluded that the ultrasonographic values determined in this study can be used as references for the diagnosis of gastrointestinal disease in dogs.

• 한국음향학회지
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• 제19권2호
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• pp.3-7
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• 2000

본 논문은 air cavity가 삽입된 중공 층상복합체 맨드릴형 광-음향센서의 감도특성에 관한 것이다. 유한요소법으로 air cavity의 두께, 포밍(foaming)층의 두께 및 맨드릴의 내경/외경비 등의 형상변수에 따른 광-음향센서의 감도특성을 분석하였다. 그 결과, 두꺼운 air cavity 및 얇은 포밍층이 설치되고, 상대적으로 높은 내경/외경 비를 갖는 맨드릴을 사용하는 것이 음향감도의 향상을 위하여 바람직하다. Air cavity를 삽입한 중공 층상복합체 맨드릴을 사용할 경우, 음향감도는 air cavity가 없는 중공 층상복합체 맨드릴형 센서에 비해 약 0.8dB 정도 향상되는 것으로 나타났다.

• 한국환경보건학회지
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• 제30권5호
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• pp.358-365
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• 2004

The photocatalytic oxidation of Rhodamine B(RhB) was studied using photocatalytic reactor filled with module of quartz tube. Module of quartz tube consisted of small quartz tube (inner diameter, 1.5 mm; outer diameter, 3 mm) bundle coated with powder $TiO_2$ and uncoated large quartz tube (inner diameter, 20 mm; outer diameter, 22 mm). Two 30 W germicidal lamp was used as the light source and the reactor volume was 0.5 l. The effects of parameters such as the coating materials and numbers, initial concentration, $H_{2}O_2$ dose and metal deposition (Ag, Pt and Fe) and simultaneous application of $H_{2}O_2$ and metal deposition. The results showed that the initial reaction constant of quartz module coated with powder $TiO_2$ was higher 1.4 time than that of the $TiO_2$ sol and optimum coating number is twice. In order to increase reaction rate, simultaneous application of photocatalytic and photo-fenton reaction using Fe coating and dose $H_{2}O_2$ dose increased reaction rate largely.

• 소성∙가공
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• 제18권8호
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• pp.607-616
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• 2009

There are three sub-processes associated with the assembly of the valve seat and cylinder head; heat fitting, cold fitting, and shrink fitting. In the heat fitting stage, the cylinder head is heated to a specified temperature and then squeezed toward the outer diameter of the valve seat. The cold fitting process cools the valve seat and safely squeezes it toward the inner diameter of cylinder head. However, these methods increased the installations & running cost and curtailed productivity. To address these problems, we analyzed the shrink fitting process using the contact pressure caused by fitting interference between the outer diameter of the valve seat and the inner diameter of the cylinder head. In this study, a closed form equation for predicting the contact pressure and fitting load is proposed. For quality control of the assembly line, principal factors of the shrink fitting process influenced in contact pressure were simulated by the FEM. Actual loads measured in the field showed good agreement with the results obtained by theoretical and finite element analysis.

• 한국임상수의학회지
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• 제14권2호
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• pp.287-296
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• 1997

Serial ultrasonographic examinations were daily performed on 8 bitches (5 Maltese and 3 Yorkshire terrier) from day 15 until parturition to determine the size of gestational structures. Gestational age was timed from the day of ovulation (day 0), which was estimated to occur when plasma progesterone concentration was first increased above 4.0 ng/ml. When the size of fetal and extra-fetal structures according to gestational age was measured, there was a difference between Maltese and Yorkshire terrier in extra-fetal structures (P<0.001), and no difference in fetal structrures (P<0.001). The correlations between the gestational age and the growth in fetal and extra-fetal structures were examined by regression analysis. The extra-fetal structure which showed high correlation from day 20 to 35 was inner chorionic cavity diameter in two breeds. The fetal structures which showed high correlation from day 36 until parturition was fetal head diameter in two breeds. In conclusions inner chorionic cavity diameter was the most accurate for estimation of gestational age and prediction of whelping day from day 20 to 35, and fetal head diameter from day 36 to parturitions respectively. Ultrasonography is very useful tool to evaluate the gestational age and to predict the whelping day in pet dogs.