• Archives of Pharmacal Research
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• 제5권2호
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• pp.61-70
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• 1982

Sulfisoxazole, a chemotherapeutic agent, was microencapsulated with ethylcellulose by means of phase separation form cyclohexane by temperatture change. The size distribution was determined by use of standard sieves and the effect of core to wall ratio was noted. To examine their shapes and usrface characteristics, the microcapsules were observed with a scanning electron microscope. Release of the drug from microcapsules into pH 7.5 buffer medium was studied. The release pattern was found to have similar properties to the release of a drug from an insoluble porous matrix reported. The apparent diffusion coefficient of sulfisoxazole was measured for the transport of the drug from the core of microcapsules into the surronding sink condition. The apparent diffusion coefficient increased with increasing capsule size.

• Computers and Concrete
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• 제18권5호
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• pp.937-950
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• 2016

This study applied autoclave expansion and heat curing to accelerate the hydration of concrete and investigated how these methods affect the expansion rate, crack pattern, aggregate size effect, and expansion of electric arc furnace oxidizing slag (EOS)-containing concrete. An expansion prediction model was simulated to estimate the expansion behavior over a long period and to establish usage guidelines for EOS aggregates. The results showed that the EOS content in concrete should range between 20% and 30% depending on the construction conditions, and that coarse aggregates with a diameter of ${\geq}4.75-mm$ are not applicable to construction engineering. By comparison, aggregates with a size of 1.18-0.03 mm resulted in higher expansion rates; these aggregates can be used depending on the construction conditions. On Day 21, the prediction model attained a coefficient of determination ($R^2$) of at least 0.9.

• Computers and Concrete
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• 제33권2호
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• pp.147-162
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• 2024

This study presents a random-aggregate mesoscale model integrating the random distribution of the coarse aggerates and the damage mechanics of the mortar and interfacial transition zone (ITZ). This mesoscale model can generate the random distribution of the coarse aggregates according to the prescribed particle size distribution which enables the automation of the current methodology with different coarse aggregates' distribution. The main innovation of this work is to propose the "correction factor" to eliminate the dimensionally dependent mesh sensitivity of the concrete damaged plasticity (CDP) model. After implementing the correction factor through the user-defined subroutine in the randomly meshed mesoscale model, the predicted fracture resistance is in good agreement with the average experimental results of a series of geometrically similar single-edge-notched beams (SENB) concrete specimens. The simulated cracking pattern is also more realistic than the conventional concrete material models. The proposed random-aggregate mesoscale model hence demonstrates its validity in the application of concrete fracture failure and statistical size effect analysis.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
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• pp.473-477
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• 2003

In this paper, a integrated structure of a two-element microstrip patch antenna with two feeds for GPS/PCS dual-band operation is proposed. The radiating element for PCS operation is a novel broad band low-profile cylindrical monopole top-loaded with a shorted meander patch, which gives linearly polarized conical radiation pattern and size reduction of patch due to meander line. The radiating element for GPS operation is a novel square-ring microstrip patch with truncated corners and slits. which provide circularly polarized broadside radiation patterns and size reduction due to slots. using dielectric substrate in GPS antenna of proposed antenna provide to improve isolation between two feeds and reduce size of patch. The proposed antenna achieves the bandwidth and polarization requirements of GPS and PCS systems.

• 복식문화연구
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• 제6권4호
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• pp.238-246
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• 1998

According to several pilot tests, petite women have their own body proportion which is not simply an overall diminutive reflection of the proportion of Misses sizes. Apparel manufacturers and pattern companies do not consider racial differences nor do they consider petite women's own specific body proportions in their size categories to produce petite garments. The primary objectives of this study was to describe the petite women's body proportions especially the differences between Asian and Caucasian petite women and to compare their body proportions to the average body figure. A physical body measurement chart was developed and revised through a pretest. Sixty subjects, thirty for each group of Asian and Caucasian. They were landmarked using an anthropometric instrument and photographed using the method of somatography for analysis of body proportions. Data were analyzed by t-test for a description of the petite subject's body proportion. The results of this study indicated that the Caucasian subjects had generally a longer lower torso than tehAian subjects in their body proportions. both subject groups had differnt body proportions from the aerage body figure.

• 전기학회논문지
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• 제62권12호
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• pp.1719-1724
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• 2013

In this paper, a size-reduction technique is presented for the RFID reader antenna working at two UHF bands. To tackle the problem of size increase in multi-band applications, two resonance paths are made to occur in one geometry with a single feed. While one resonance path is combined with the other, the entire geometry is determined to guarantee the resonance at the target frequencies through the dual-band input impedance matching. The antenna performance is predicted by the full-wave simulation, and the design method is verified by observing the good agreement between the simulated and measured results. At the two frequencies, the satisfactory return loss as well as the antenna efficiency and peak gain of the far-field pattern is obtained.

• Bulletin of the Korean Chemical Society
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• 제23권8호
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• pp.1127-1134
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• 2002

Fine ceramic particles of zirconia toughened alumina (ZTA), titania toughened alumina (TTA), and zirconia-titania toughened alumina (ZTTA) have been synthesized by ultrasonic spray pyrolysis (USP) at various temperatures from starting salt solutio ns of various compositions aiming for the development of catalytic material. These particles were characterized for properties such as shape, size and size distribution, diffraction pattern, and chemical and phase composition of elements by scanning electron microscopy (SEM), particle size analyzer (PSA), x-ray diffraction (XRD), and inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Chemical compositions and sizes of ceramic composites have been controled by the stoichiometry of salt solutions and the flow rate of spraying solutions. The optimum experimental conditions for the various composite particle syntheses have been proposed.

• International Journal of Automotive Technology
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• 제6권2호
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• pp.87-93
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• 2005

Spray patterns were visualized using the shadowgraph method, and the droplet size and velocity were measured using PDPA for high-pressure injections up to 2,600 bars. The spray pattern and spray characteristics, such as penetration, spray width, spray angle, droplet size, injection duration, and droplet velocity, were investigated to determine the suitable injection pressure. Spray penetration, width, angle, and velocity increased continuously up to 2,600 bars with the injection pressure in a high-pressure region. The rate of improvement of the above spray characteristics, however, declined rapidly, when the injection pressure reached 2,000 bars. The injection duration and droplet size generally decreased with the increase in the injection pressure, while the rate of improvement decreased abruptly after 2,000 bars. Consequently, the improvement rate of the spray characteristics became blunt at over 2,000 bars. This means that the suitable injection pressure is around 2,000 bars.

• 한국분무공학회지
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• 제3권1호
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• pp.27-33
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• 1998

Correlations of drop size and velocity in a spray from the disintegration of liquid jet and liquid film from an internal mixing twin-fluid atomizer, were determined by phase Doppler method. The distribution pattern of Sauter mean diameter(SMD) in a spray was changed by a behavior of liquid flow. As smaller droplets became faster and slower easily by the surrounding conditions, the correlation between drop size and mean velocity was found to be varied as next 3 steps; firstly smaller droplets have a higher mean velocity at the area near atomizer, droplets have almost the same mean velocity and finally larger droplets have a higher mean velocity at the area far from an atomizer.

• 대한가정학회지
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• 제40권11호
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• pp.1-9
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• 2002

Nowadays, the use of apparel CAD system is important to the mass production of ready to wear Especially, computer-based grading is the most important process to improve the fitness of clothes and to reduce the time needed to make patterns of several sizes. The purpose of this study was to suggest a standard sizing system for junior-high school girls' lower clothes and to suggest a grading method according to the sizing systems. The subjects were 402 junior-high school girls of 13 to 15 year's-old. The size intervals of waist girth and hip girth were 3㎝ and 4㎝ respectively. The sizing system, which had frequencies more than 4.5%, was classified 8 cases. For regular grading, two types of group were classified into 58-82/61-86/64-90/67-94 and 61-82/64-86/67-90/70-94. Among them, 61-86 and 64-86 size were adopted the basic size for the development of grading. According to the sizing system, hand-made patterns were manufactured. By measure of the each part of the slacks, new grading rule patterns were developed by each size. A new grading rule was different from the Moonwha grading rule. This result will contribute to clothing fitness of consumer and the amount of production.