• Journal of the Korean Ceramic Society
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• v.40 no.4
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• pp.350-353
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• 2003

Millimeter-wave dielectric ceramics have been used like applications for ultrahigh speed wireless LAN because it reduces the resources of electromagnetic wave, and Intelligent Transport System (ITS) because of straight propagation wave. For millimeterwave, the dielectric ceramics with high quality factor (Q$.$f), low dielectric constant($\varepsilon$), and nearly zero temperature coefficient of resonant frequency ($\tau$) are needed. No microwave dielectric ceramics with these three properties exist except Ba(Mg$\_$1/3/Ta/sub1/3/)O$_3$ (BMT), which has a little high s: In this paper, alumina (Al$_2$O$_3$) and fosterite (Mg$_2$SiO$_4$), candidates for millimeter-wave applications, were studied with an objective to get high q$.$f and nearly zero $\tau$$\_$f/ For alumina ceramics, q$.$f more than 680,000 GHz was obtained but it was difficult to obtain nearly zero Qf. On the other hand, for forsterite ceramics, q$.$f was achieved from 10,000 GHz of commercial for sterite to 240,000 GHz of highly purified MgO and SiO$_2$ raw materials, and $\tau$$\_$f/ was reduced a few by adding TiO$_2$ with high positive $\tau$$\_$f/.

• Journal of Ocean Engineering and Technology
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• v.25 no.6
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• pp.91-96
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• 2011

In this paper, friction welded joints were constructed to investigate the mechanical properties of welded 15-mm diameter solid bars of Mg alloy (AZ31B). The main friction welding parameters were selected to endure reliable quality welds on the basis of visual examination, tensile tests, impact energy test, Vickers hardness surveys of the bonds in the area and heat affected zone (HAZ), and macrostructure investigations. The study reached the following conclusions. The tensile strength of the friction welded materials (271 MPa) was increased to about 100% of the AZ31B base metal (274 MPa) under the condition of a heating time of 1 s. The metal loss increased lineally with an increase in the heating time. The following optimal friction welding conditions were determined: rotating speed (n) = 2000 rpm, heating pressure (HP) = 35 MPa, upsetting pressure (UP) = 70 MPa, heating time (HT) = 1 s, and upsetting time (UT) = 5 s, for a metal loss (Mo) of 10.2 mm. The hardness distribution of the base metal (BM) showed HV55. All of the BM parts showed levels of hardness that were approximately similar to friction welded materials. The weld interface of the friction welded parts was strongly mixed, which showed a well-combined structure of macro-particles without particle growth or any defects. In addition, an acoustic emission (AE) technique was applied to derive the optimum condition for friction welding the Mg alloy nondestructively. The AE count and energy parameters were useful for evaluating the relationship between the tensile strength and AE parameters based on the friction welding conditions.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.2
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• pp.263-268
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• 2003

In this paper, we have investigated double gate (DG) MOSFET structure, which has main gate (NG) and two side gates (SG). We know that optimum side gate voltage for each side gate length is about 3V in the main gate 50nm. Also, we know that optimum side gate length for each for main gate length is about 70nm. DG MOSFET shows a small threshold voltage roll-off. From the I-V characteristics, we obtained IDsat=550$mutextrm{A}$/${\mu}{\textrm}{m}$ at VMG=VDS=1.5V and VSG=3.0V for DG MOSFET with the main gate length of 50nm and the side gate length of 70nm. The subthreshold slope is 86.2㎷/decade, transconductance is 114$mutextrm{A}$/${\mu}{\textrm}{m}$ and DIBL (Drain Induced Barrier Lowering) is 43.37㎷. Then, we have investigated the advantage of this structure for the application to multi-input NAND gate logic. Then, we have obtained very high cut-off frequency of 41.4GHz in the DG MOSFET.

• Korean Journal of Community Nutrition
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• v.14 no.2
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• pp.147-157
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• 2009

The purpose of this study was to find out the information on nutrition labeling and how many calories and nutrients the high school students consumed for 1 day from cookies. A total of 74 male and female high school students in Suwon were surveyed and 56 cookies that they consumed were examined. Background data were collected by questionnaire, cookie intake by 24-hr recall, and the calories and nutrients content in cookies and the amount of intake by nutrition information on the wrapping paper of cookie. The statistical analysis for the data was done by SPSS 12.0. Energy contents in 1 serving size of cookie were $90{\sim}315\;kcal$, average of 170 kcal. The protein contents were $0{\sim}7\;g$, fat $2{\sim}20\;g$, cholesterol $0{\sim}55\;mg$, and sodium $30{\sim}390\;mg$ in 1 serving size of cookie. Most of the cookies(80%) examined contained no trans fat at all, which is desirable. Among the types of cookies, snacks contained higher quantities of calories and sodium, the pie contained more sugar and cholesterol, and the biscuit had more trans fat. One fourth of the cookies examined belonged to 'high calorie, low nutritious food' according to the criteria proposed by The Ministry for Health, Welfare and Family Affairs. Thus the excessive intake of cookies might result in nutritional imbalance. There were large differences in calorie intake among students, from zero who did not intake any cookies at all to maximum 818 kcal/day, an average of 75 kcal/day. When the students who did not intake cookies were excluded, energy 205 kcal. fat 10 g, sodium 177 mg were consumed from the cookie for a 1 day on average.

• Korean Journal of Food Science and Technology
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• v.10 no.2
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• pp.194-202
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• 1978

In order to evaluate the utility of the anthocyanin pigments in Ganges Amaranth as an edible pigment, this study was designed to isolate and identify the anthocyanins. The anthocyanins present in leaves of Ganges Amaranth were extracted with 0.1% HCl in methanol. The extracted pigments were purified by organic solvent treatment and Amberlite CG-400 Type cation exchanger, and then separated into individual pigments by paper chromatography with n-butanol-formic acid-water(100:25:60, v/v) as a solvent system. The separated pigments were identified by their Rf values, sugar moieties, complete hydrolysis and spectral characteristics in the visible and ultraviolet regions. The amounts of individual anthocyanins were also determined. The results obtained from these experiments were as follows. 1. Chromatograms of the Ganges Amaranth extract developed with BFW yielded three anthocyanin bands. The two of the anothocyanin bands were tentatively identified as malvidin-3-glucoside(acylated with caffeic acid) in band 1 and peonidin-3-glucoside (acylated with caffeic acid) in band 2. But the anthocyanin in band 3 was not identified due to extremly low concentration. 2. The amount of total anthocyanins was 101.57 mg/100g fresh weight of leaves in which 82.15 mg of malvidin-3-glucoside (acylated with caffeic acid) and 27.20 mg of peonidin-3-glucoside(acylated with caffeic acid) were contained per 100g fresh weight. Maividin-3-glucoside acylated with the acid was, therefore, the most abundant pigment in the Ganges Amaranth.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.263-268
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• 2017

A hot forming process is required for Mg alloys to enhance the formability and plastic workability due to the insufficient formability at room temperature. Mg alloy undergoes dynamic recrystallization (DRX) during the hot working process, which is a restoration or softening mechanism that reduces the dislocation density and releases the accumulated energy to facilitate plastic deformation. The flow stress curve shows three stages of complicated strain hardening and softening phenomena. As the strain increases, the stress also increases due to work hardening, and it abruptly decreases work softening by dynamic recrystallization. It then maintains a steady-state region due to the equilibrium between the work hardening and softening. In this paper, an efficient optimization process is proposed for the material model of the dynamic recrystallization to improve the accuracy of the flow curve. A total of 18 variables of the constitutive equation of AZ80 alloy were systematically optimized at an elevated forming temperature($300^{\circ}C$) with various strain rates(0.001, 0.1, 1, 10/sec). The proposed method was validated by applying it to the constitutive equation of AZ61 alloy.

• The Korean Journal of Pharmacology
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• v.18 no.2
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• pp.45-50
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• 1982

Yeum et al. formulated a new hot-plate method using the threshold temperature, and there are some controversies on the effects of naloxone and diazepam on the antinociceptive action. In this paper, the comparison of three methods registering analgesic activity and the application of the new hot-plate method formulated by Yeum et al. on the study of the influences of naloxone and diazepam on the analgesic effect of morphine were tried in male mice. The results obtained were summarized as follows; 1) The least-square regression lines of the morphine analgesia plotted against log-dose showed the correlation coefficient of above 0.90, but the competitive antagonism produced by naloxone (0.1 mg/kg) against the analgesia was more prominently demonstated by the new hot-plate method than the other methods: original hot-plate method and electrical stimulation method. 2) In the experiment using the new hot-plate method, the log dose-response curve of morphine (y=7.30 x+49.80, r=0.998) was shifted to the right by the pretreatment of naloxone (0.1 mg/kg), but was slightly shifted to the left by the pretreatment of diazepam (2.5 mg/kg). This study suggests that for the analgesia experiment, the new hot-plate method is superior to the original hot-plate method or the electrical stimulation method, and that the potentiative effect of diazepam on the morphine anagesia is not significant.

• Journal of the Korean Wood Science and Technology
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• v.35 no.5
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• pp.24-37
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• 2007

The Korean Ministry of Environment started controlling indoor air quality (IAQ) in 2004 through the introduction of a law regulating the use of pollutant emitting building materials. The use of materials with formaldehyde emission levels above $1.25 mg/m^2{\cdot}h$ (JIS A 1901, small chamber method) has been prohibited. This level is equivalent to the $E_2$ grade ($>5.0mg/{\ell}$) of the desiccator method (JIS A 1460). However, the $20{\ell}$ small chamber method requires a 7-day test time to obtain the formaldehyde and volatile organic compound (VOC) emission results from solid building interior materials. As a approach to significantly reduce the test time, the field and laboratory emission cell (FLEC) has been proposed in Europe with a total test time less than one hour. This paper assesses the reproducibility of testing formaldehyde and TVOC emissions from wood-based composites such as medium density fiberboard (MDF), laminate flooring, and engineered flooring using three methods: desiccator, perforator and FLEC. According to the desiccator and perforator standards, the formaldehyde emission level of each flooring was ${\le}E_1$ grade. The formaldehyde emission of MDF was $3.48 mg/{\ell}$ by the desiccator method and 8.57 g/100 g by the perforator method. To determine the formaldehyde emission, the peak areas of each wood-based composite were calculated from aldehyde chromatograms obtained using the FLEC method. Formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde and benzaldehyde were detected as aldehyde compounds. The experimental results indicated that MDF emitted chloroform, benzene, trichloroethylene, toluene, ethylbenzene, m,p-xy-lene, styrene, and o-xylene. MDF emitted significantly greater amounts of VOCs than the floorings did.

• Proceedings of the Korean Society of Tobacco Science Conference
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• 1997.10a
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• pp.91-113
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• 1997

One mg tar cigarettes represent a growing segment of the market, in various parts of the world but specially in the Far East. Cigarette design of ultra low tar cigarettes is not easy to manage: a simple extension of the techniques used in the design of the low tar segment will usually lead to tasteless cigarettes. A detailed analysis of the design of commercial ultra low tar cigarettes in different countries shows that no 《dominant design》 has yet been adopted. Blend composition, blend density, filter design, degree of filter ventilation all vary in a large range from cigarette brand to cigarette brand, and will influence the puff number, the tar concentration in each puff and ultimately the taste. We will report and comment on the detailed analysis of 17 commercial brands of ultra low tar cigarettes. We will then review the specific influence of tobacco chemical composition, introduction of reconstituted tobacco, influence of cigarette paper characteristics, selection of filter ventilation components on the burn characteristics and tar delivery; to conclude that the commercial success of an ultra low tar cigarette is linked to a very delicate balance between this techniques and... good marking of course!

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.10
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• pp.1044-1051
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• 2003

In this paper, a compact planar microwave duplexer on the high dielectric substrate is presented. As the Ba(Mg$\sub$1/3/Ta$\sub$2/3/)O$_3$(BMT) has good dielectric performances with a high dielectric constant of $\varepsilon$$\sub$r/=23, it is suitable to apply to a printed circuit board fur reducing its circuit size. The BMT substrate is fabricated by using a tape casting fabrication process, and circuit patterns are screen-printed on it by suing silver paste. The open-loop ring type duplexer is designed and implemented on the BMT substrate, and it achieves the smaller size by 80% than one on a commercial substrate($\varepsilon$$\sub$r/=6.15) without degenerating its performance. Therefore the proposed BMT substrate has provided the miniaturization of the duplexer, moreover it can make a contribution towards reducing the size of microwave passive circuits.