• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2000.04a
• /
• pp.205-206
• /
• 2000

In this paper, we consider variable sized bin packing problem, where the objective is not to minimize the total space used in the packing but to minimize the total cost of the packing when the cost of unit size of each bin does not increase as the bin size increases. A heuristic algorithm is described, and analyzed in two special cases: 1) b$\sub$m/｜…｜b$_1$and w$\sub$n/｜…｜w$_1$, and 2) b$\sub$m/｜…｜b$_1$, where b$\sub$i/ denotes the size of i-th type of bin and w$\sub$j/ denotes the size of j-th item. In the case 1), the algorithm guarantees optimality, and in the case 2), it guarantees asymptotic worst-case performance bounds of l1/9.

• 제어로봇시스템학회:학술대회논문집
• /
• 1987.10b
• /
• pp.370-375
• /
• 1987

Damping piston with an orifice in the piston head is utilized to improve the damping characteristics of a pneumatic push-push type rotary actuator. Through linearized analysis, the optimum size of orifice, which gives maximum damping effect at the frequency where damping is desired. most, is predicted. The frequency response test of teal system were carried out to see the effects of damping piston and to obtain true optimum size of orifice by trying orifices of various size near the predicted value. During the tests, both air and helium were tried as working fluid, and a lag-lead compensation circuit was incorporated to improve system dynamics. The finally chosen orifice size is a little bigger than that predicted from analysis, however it gives high damping effects for the finally designed pneumatic system enough to have wide frequency response bandwidth.

• Proceedings of the KIEE Conference
• /
• 1996.07c
• /
• pp.1816-1818
• /
• 1996

A micro-size nonthermal plasma generator, using a $SiO_2$ film as a dielectric barrier, has been studied experimentally for a high frequency ac voltage in 2LPM oxygen gas fed. The $SiO_2$ film as a micro-size dielectric barrier was made by the wet oxidation of n-type Si wafer($220[{\mu}mt]$). It can be generated ozone, as a nonthermal plasma intensity parameter, at very low level of applied voltage about 1[kV] by using the micro-size dielectric barrier. As a result, in case that have no air gap spacing i.e. surface discharge case shows relatively higher ozone concentration rather than that case of the micro-airgap spacing.

• Journal of the Korean Applied Science and Technology
• /
• v.17 no.4
• /
• pp.257-261
• /
• 2000

Monodisperse polymer particles have many industrial applications such as surface coatings for metal panels, chromatographic media, spacers for liquid crystal display panel, and fillers for cosmetics, etc.. Micron-size monodispersed poly(methyl methacrylate) particles were prepared by dispersion polymerization in methanol medium in the presence of poly(vinyl pyrrolidone) and 2,2'-azobis(isobutyronitrile) as steric stabilizer and initiator, respectively. Effects of polymerization parameters, such as monomer and initiator concentration, stabilizer type and concentration, solvent composition on average particle size and size distribution were studied.

• Elastomers and Composites
• /
• v.33 no.2
• /
• pp.110-116
• /
• 1998

A new technology was introduced to the emulsion polymerization. It is the ultrasonic activation method which replaced a chemical initiator and the environmentally benign process. In this study, free radicals were produced by a pulse type ultrasound energy irradiation, then polystyrene latex was polymerized without chemical initiator. With ultrasonic energy density, the degree of polymerization, average molecular weight, and particle size were increased, but the polydispersity index for the molecular weight and the particle size were decreased. The optimum condition of emulsifier concentration and temperature was found to be 1.0 wt.% SDS and $40^{\circ}C$, respectively. As a result, the emulsion polymerization process without chemical initiator was proved to be comparable to common latex properties such as average molecular weight, molecular weight distribution, particle size, etc.

• ETRI Journal
• /
• v.28 no.5
• /
• pp.607-614
• /
• 2006

This paper presents a new class of microstrip slow-wave open-loop resonator filters with reduced size and improved stopband characteristics. A comprehensive treatment of both ends loaded with triangular and rectangular ends is described, leading to the invention of a microstrip slow-wave open-loop resonator. Two-resonator and four-resonator bandpass filters are designed at the operating frequency of about 2 GHz, and a bandwidth of 60 MHz. The size of the slow-wave open-loop resonator is optimized from the standpoint of the unloaded Q-factor. The filters are not only compact in size due to the slow-wave effect, but also have a wider upper stopband resulting from the dispersion effect. The filter designs of this type are described in details. The experimental results are demonstrated and discussed.

• Bulletin of the Korean Chemical Society
• /
• v.32 no.1
• /
• pp.117-121
• /
• 2011

Size-controlled Ag nanoparticles (NPs) were prepared from the decomposition of Ag(I) carboxylates using ethanolamine derivatives as a reducing agent without an additional stabilizing agent. The size of the Ag NPs with a narrow size distribution (sub-10 nm to ca. 40 nm) was controlled precisely by varying the processing parameters, such as the type of reducing agent and the chain length of the carboxylate in the Ag(I) carboxylate. The optical properties, surface composition and crystallinity of the Ag NPs were characterized by ultraviolet-visible spectroscopy, gas chromatography-mass spectrometry, thermal gravimetric analysis, transmission electron microscopy and X-ray diffraction.

• The Bulletin of The Korean Astronomical Society
• /
• v.41 no.1
• /
• pp.69.2-69.2
• /
• 2016

We study the environmental dependence of the mass-size relation for the most massive early type galaxies (M>$10^{10.7}M_{\odot}$) in the redshift range 0.10~0.15. The sizes of galaxies are measured by non-parametric method. We find that galaxies more massive than $10^{11.1}M_{\odot}$ show the environmental dependence in the mass-size relation. The galaxies with M>$10^{11.1}M_{\odot}$ located in the densest, cluster like environment have larger sizes and extended surface brightness profiles than their counterparts located in a low dense environment. We also find that the environmental dependence of the mass-size relation is more significant for the brightest cluster galaxies (BCGs) than non-BCGs. We use the semi analytic galaxy formation simulation based on the Millennium 1 Simulation for interpretation. Our result can be explained with a hierarchical growth of the most massive galaxies through dissipation-less merger in dense environment.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2022.04a
• /
• pp.251-252
• /
• 2022

The microfluidic controlled droplet manufacturing system is one of the most powerful methods for capsule manufacturing. The microfluidic control method can control the type and size of the capsule by changing the size and configuration of the channel. In addition, by increasing the number of channels, capsules of uniform size can be mass-produced. In this paper, a capsule manufacturing system including flow-focusing and T junction method was designed. In addition, the effectiveness of this system was verified by manufacturing multi-emulsion capsules with a size of 2.2 to 3 mm.

• The Journal of Internal Korean Medicine
• /
• v.33 no.4
• /
• pp.429-437
• /
• 2012

Objectives : Obesity is an important cause of diabetes, and lipotoxicity causes insulin resistance. In this study, we investigated the effects of Salvia miltiorrhiza on high fat diet-induced obese type 2 diabetic mouse models. Methods : Diabetes was induced in ICR male mouse (23~25 g) with Surwit's high fat, high sucrose diet. Mice were divided into 4 groups (n=10) of normal, control, Salvia miltiorrhiza, and metformin. After 8 weeks, body weight, OGTT, fructosamine, lipid profile, serum level of adiponectin and leptin, epididymal fat pad, liver weight and epididymal adipocyte size were measured. Results : Salvia miltiorrhiza significantly reduced oral glucose tolerance levels, fructosamine serum level, epididymal fat weight, and epididymal adipocyte size. Salvia miltiorrhiza also increased HDL-cholesterol, adiponectin and leptin serum levels. Conclusions : These results show that Salvia miltiorrhiza improves insulin resistance. Therefore we suggest that Salvia miltiorrhiza would be an effective treatment for obese type 2 diabetic patients.