• Advances in concrete construction
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• v.7 no.3
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• pp.191-201
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• 2019

Bamboo concrete bond behaviour is investigated through pullout test in this work. The bamboo strip to be used as reinforcement inside concrete is first treated with chemical adhesive to make the bamboo surface impermeable. Various surface coatings are explored to understand their water repellant properties. The chemical action at the bamboo concrete interface is studied through different chemical coatings, sand blasting, and steel wire wrapping treatment. Whereas mechanical action at the bamboo concrete interface is studied by developing mechanical interlock. The result of pullout tests revealed a unique combination of surface treatment and grooved bamboo profile. This combination of surface treatment and a grooved bamboo profile together enhances the strength of bond. Performance of a newly developed grooved bamboo strip is verified against equivalent plain rectangular bamboo strip. The test results show that the proposed grooved bamboo reinforcement, when treated, shows highest bond strength compared to treated plain, untreated plain and untreated grooved bamboo reinforcement. Also, it is observed that bond strength is majorly influenced by the type of surface treatment, size and spacing of groove. The changes in bamboo-concrete bond behavior are observed during the experimentation.

• Journal of Radiation Protection and Research
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• v.41 no.3
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• pp.216-221
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• 2016

Background: Very fine radiation-induced aerosol particles are produced in intense radiation fields, such as high-intensity accelerator rooms and containment vessels such as those in the Fukushima Daiichi nuclear power plant (FDNPP). Size measurement of the aerosol particles is very important for understanding the behavior of radioactive aerosols released in the FDNPP accident and radiation safety in high-energy accelerators. Materials and Methods: A combined technique using wire screens and imaging plates was developed for size measurement of fine radioactive aerosol particles smaller than 100 nm in diameter. This technique was applied to the radiation field of a proton accelerator room, in which radioactive atoms produced in air during machine operation are incorporated into radiation-induced aerosol particles. The size of $^{11}C$-bearing aerosol particles was analyzed using the wire screen technique in distinction from other positron emitters in combination with a radioactive decay analysis. Results and Discussion: The size distribution for $^{11}C$-bearing aerosol particles was found to be ca. $70{\mu}m$ in geometric mean diameter. The size was similar to that for $^7Be$-bearing particles obtained by a Ge detector measurement, and was slightly larger than the number-based size distribution measured with a scanning mobility particle sizer. Conclusion: The particle size measuring method using wire screens and imaging plates was successfully applied to the fine aerosol particles produced in an intense radiation field of a proton accelerator. This technique is applicable to size measurement of radioactive aerosol particles produced in the intense radiation fields of radiation facilities.

• Journal of the Korean Society of Clothing and Textiles
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• v.26 no.6
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• pp.821-832
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• 2002

The purpose of this study was to develop grading method of the basic brassiere patterns therewith, provide for 12 size's brassiere patterns and prove fitness of their's and shape. The collected data were statistically processed using the SAS 6.12 for Means, Standard Deviation, etc. The results of this study can be summarized as follows; 1. The basic sizes adopted at the first design stage (see fig.1-2) were 75AA, 75A and 75B each of which was designed as upper foundation basic pattern in reference to the cup size. At the second stage, each of the upper body foundation basic pattern was used to design lower cup, upper up, front panel and wing in their order(see fig.3-6). At the third stage, the other sizes were graded in reference to the three brassiere patterns (75AA, 75A and 75B) to produce 12 brassiere sizes(see Tab. 7-8). In order to develop the basic patterns of adult women's brassieres, 33 women were selected per 11 size combination(3 women per size combination), and then, their brassiere fitting was teated. As a result, the fronts of the basic patterns were found to have such problems as undone front center, poor levelling of upper cup's bottom line or lower cup's top line, poor shape of upper cup's outside top line and shoulder strip position. On the other hand, on the rear side of the basic patterns, the central part of the wing was slightly lifted, while the wing width and straps'interval did not befit the ful1-cup brassiere. The result of this first brassiere fitting test showed that the functionality and aesthetics of the basic pattern brassieres were more or less satisfactory, and thus, the problems were addressed for the second teat. In the second test, the aesthetics, breast-shaping effect and functionality of the basic pattern brassieres were much improved. 2. We were to present the final brassiere sizing system to extend the interior length of breast and the exterior length of breast on the basis of fitting test. Thereby, 75B$.$80A$.$80B$.$85A$.$85B's the interior lengths of breast were enlarged to 0.7cm, the rest size was enlarged to 0.5cm and the exterior length of breast was enlarged to 0.5cm regardless of sizes. 3. The upper foundation basic patterns of 75AA and 75B were presented and and the basic brassiere pattern and grading pattern were presented through to.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.3
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• pp.251-258
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• 2011

To investigate whether the rearing environmental factors (size heterogeneity, rearing density, and feeding frequency) affect the growth and cannibalism of fry in cultured puffer Takifugu obscurus, we conducted three experiments. To examine size effects, we used small (total length [TL] $26.0{\pm}0.5\;mm$, body weight [BW] $0.18{\pm}0.01\;g$), medium (TL $23.1{\pm}0.1\;mm$, BW $0.28{\pm}0.01\;g$), large (TL $26.0{\pm}0.2\;mm$, BW $0.48{\pm}0.01\;g$) and small-large size combination groups. For density, we used size-matched puffers (TL $25.0{\pm}0.5\;mm$, BW $0.53{\pm}0.03\;g$) and five density were examined ranging from 1.43 to 7.14 individuals/L. For the feeding frequency, we also used size-matched fry and feeding frequencies of three times/2 days, one time/day, two times/day, three times/day. We ran each experiment in triplicate and investigated the survival rate, daily food intake (DFI), feed efficiency (FE), and daily growth rate (DGR). The growth of the puffers increased with increasing size, density, and feeding frequency, while cannibalism increased with a greater size gap, density and lower feeding frequency. Therefore, we concluded that size, rearing density, and feeding frequency are major factors influencing growth and cannibalism of the puffer, T. obscurus.

• Journal of radiological science and technology
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• v.29 no.3
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• pp.167-175
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• 2006

With the recent prevalence of helical CT and multi-slice CT, which deliver higher radiation dose than conventional CT due to overbeaming effect in X-ray exposure and interpolation technique in image reconstruction. Although multi-detector and helical CT scanner provide a variety of opportunities for patient dose reduction, the potential risk for high radiation levels in CT examination can't be overemphasized in spite of acquiring more diagnostic information. So much more concerns is necessary about dose characteristics of CT scanner, especially dose efficient design as well as dose modulation software, because dose efficiency built into the scanner's design is probably the most important aspect of successful low dose clinical performance. This study was conducted to evaluate z-axis geometric dose efficiency in single detector CT and each level multi-detector CT, as well as to compare z-axis dose efficiency with change of technical scan parameters such as focal spot size of tube, beam collimation, detector combination, scan mode, pitch size, slice width and interval. The results obtained were as follows ; 1. SDCT was most highest and 4 MDCT was most lowest in z-axis geometric dose efficiency among SDCT, 4, 8, 16, 64 slice MDCT made by GE manufacture. 2. Small focal spot was 0.67-13.62% higher than large focal spot in z-axis geometric dose efficiency at MDCT. 3. Large beam collimation was 3.13-51.52% higher than small beam collimation in z-axis geometric dose efficiency at MDCT. 4. Z-axis geometric dose efficiency was same at 4 slice MDCT in all condition and 8 slice MDCT of large beam collimation with change of detector combination, but was changed irregularly at 8 slice MDCT of small beam collimation and 16 slice MDCT in all condition with change of detector combination. 5. There was no significant difference for z-axis geometric dose efficiency between conventional scan and helical scan, and with change of pitch factor, as well as change of slice width or interval for image reconstruction. As a conclusion, for reduction of patient radiation dose delivered from CT examination we are particularly concerned with dose efficiency of equipment and have to select proper scanning parameters which increase z-axis geometric dose efficiency within the range of preserving optimum clinical information in MDCT examination.

• Journal of the Korean Ceramic Society
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• v.45 no.9
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• pp.507-511
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• 2008

A "C-sphere" specimen geometry was used to determine the failure strength distributions of a commercially-available bearing-grade silicon nitride ($Si_3N_4$) with ball diameters of 12.7 and 25.4 mm. Strengths for both diameters were determined using the combination of failure load, C-sphere geometry, and finite element analysis and fitted using two-parameter Weibull distributions. Effective areas of both diameters were estimated as a function of Weibull modulus and used to explore whether the strength distributions predictably scaled between each size. They did not. That statistical observation suggested that the same flaw type did not limit the strength of both ball diameters indicating a lack of material homogeneity between the two sizes. Optical fractography confirmed that. It showed there were two distinct strength-limiting flaw types common to both ball diameters, that one flaw type was always associated with lower strength specimens, and that a significantly higher fraction of the 25.4-mm-diameter C-sphere specimens failed from it. Predictable strength-size-scaling would therefore not result as a consequence of this because these flaw types were not homogenously distributed and sampled in both C-sphere geometries.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.993-996
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• 2005

High speed machining(HSM) technique is widely used in the appliance, automobile part and mold industries, which has many advantages such as good quality, low cost and rapid machining time. but it also has problems like tool break, smooth tool path, and so on. In particular, small size end mill is easy to break, so it must be changed before interrupting operation. Generally, the tool life of small size end mill is effected by the milling conditions whose evaluated parameters are spindle, feedrate, and width of cut. The experiments are carried out by full factorial design of experiments using and orthogonal array. This paper shows optimal combination and mathematical model for tool life, and the analysis of variance(ANOVA) is employed to analyze the main effects and the interactions of these milling parameters and the second-order polynomial regression model with three independent variables is estimated to predict tool life by multiple regression analysis.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.734-738
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• 2002

We present spectral characteristics of tidal flat sediments and algal mat that were tested in the Gomso and Saemangum tidal flats, Korea. The objective of this study is to investigate the spectral reflectance and the radar scattering modeling in the tidal flats. Ground truth data obtained in the tidal flats include grain size, soil moisture content and its variation with time, surface roughness, chlorophyll, ground leveling, and field spectral reflectance measurement. The concept of an effective exposed area (EEA) is introduced to accommodate the effect of remnant surface water, and it seriously affects the reflection of short wavelength infrared and microwave. The nin size of 0.0625 mm has been normally used as a critical size of mud and sand discrimination. But we propose here that 0.25 mm is more practical grain size criterion to discriminate by remote sensing. Algal mat is the primary product in tidal flats, and it is found to be very important to understand spectral characteristics for tidal flat remote sensing. We have also conducted radar scattering modeling, and showed L-band HV-polarization would be the most effective combination.

• Carbon letters
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• v.25
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• pp.50-54
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• 2018

Large-size graphene samples are successfully prepared by combining ultrosonic assisted liquid phase exfoliation process with oxidation-deoxidation method. Different from previous works, we used an ultrasound-treated expanded graphite as the raw material and prepared the graphene via a facile oxidation-reduction reaction. Results of X-ray diffraction and Raman spectroscopy confirm the crystal structure of the as-prepared graphene. Scanning electron microscopy images show that this kind of graphene has a large size (with a diameter over $100{\mu}m$), larger than the graphene from graphite powder and flake graphite prepared through single oxidation-deoxidation method. Transmission electron microscopy results also reveal the thin layers of the prepared graphene (number of layers ${\leq}3$). Furthermore, the importance of preprocessing the raw materials is also proven. Therefore, this method is an attractive way for preparing graphene with large size.

• Journal of the Korean Ceramic Society
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• v.40 no.8
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• pp.730-734
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• 2003

This research examined the effect, which it follows in particle size distribution change of CaHPO$_4$ㆍ2$H_{2}O$ (DCPD). We used two kinds of compositions; tetracalcium phosphate (TTCP)/dicalcium phosphate dihydrate (DCPD) composition and $\alpha$-tricalcium phosphate ($\alpha$-TCP)TTCP/DCPD composition. As the result, the mean particle size of the DCPD decreased, the setting tine shortened at all compositions. The reference powder (DR), which did not milling, showed about 2 times strength value compared with other milling sample. Especially, the compressive strength of 60 : 20 : 20 sample (DR(do$_{0.5}$)=12.08 $\mu\textrm{m}$) after curing 7 days in simulated body fluid solution was 40$\pm$0.5 MPa, which was the highest. This resulted from the packing density at $\alpha$-TCP/TTCP/DCPD combination.