• Journal of the Korean Institute of Telematics and Electronics B
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• v.30B no.12
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• pp.67-72
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• 1993

An adaptive block truncation coding(BTC) using human visual system(HVS) is proposed. To reduce visible blocking effect at sensitive area in HVS. a new category classification coefficient is proposed. The categroy classification coefficient was derived by combining the modified HVS and standard deviation. By computer simulations, we showed that the proposed method reduced blocking effect at low bit rate coding more than the conventional Hui's method.

• Korean Journal of Veterinary Research
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• v.33 no.1
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• pp.71-80
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• 1993

The central nervous system depressant effect of xylazine and xylazine-ketamine was studied in chicken and mice. Intraperitoneal injection of xylazine(1~30 mg/kg) and xylazine(1~30 mg/kg)-ketamine(100 mg/kg) induced a loss of the righting reflex in chicken and mice, respectively. These effects of xylazine were dose-dependent. The results obtained were as follows; 1. The effect of xylazine-induced depression was antagonized by adrenergic antagonists having ${\alpha}_2$-blocking activity(yohimbine, tolazoline, piperoxan and phentolamine). 2. Yohimbine was most effective in the reduction of the CNS depression by xylazine. 3. Phenoxybenzamine and prazosin did not reduced CNS depression by xylazine in both species. 4. Labetalol (${\alpha}_1$, ${\beta}_1$-adrenergic antagonist) and propranolol(${\beta}$-adrenergic blocking agent) were not effective in reducing xylazine induced depression. 5. Cholinergic blocking agents (atropine and mecamylamine), a dopaminergic antagonist (Haloperidol), a histamine $H_1$-antagonist(chlorpheniramine), a histamine $H_2$-antagonist(cimetidine), a serotonergic-histamine $H_1$ antagonist(cyproheptadine) were not effective in reducing xylazine-induced depression. 6. Xylazine-induced depression is mediated by ${\alpha}_2$-adrenergic receptors and appears not to be involved in cholinergic, dopaminergic, serotonergic or histaminergic pathways.

• Clinical and Experimental Reproductive Medicine
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• v.20 no.2
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• pp.149-156
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• 1993

Human chorionic gonadotropin(hCG) and intravenous immunoglobulin(IVIG) treatment were attempted as a novel therapeutic approach for unexplained recurrent spontaneous abortion(RSA). Forty-four and 3 women with a history of RSA were treated with hCG and IVIG, respectively, during pregnancy. Of these patients, serum blocking factor assay was performed before and after each treatment, in 15 patients; 12 cases with hCG and 3 cases with IVIG. The results were as follows: 1. Of 44 women who receive hCG during pregnancy, 24 delivered healthy infants at term, 10 patients suffered repeat abortion, and 10 women are still pregnant under 28 weeks. Over all success rate of hCG treatment was 70.6% (24/34). Although there is no statistical significance, absolute serm blocking level was decreased after treatment(N=12). 2. Of 3 women who receive IVIG during pregnancy, all 3 women are still pregnant under 28 weeks. Serum blocking level was increased after treatment, however, this increment was not statistically significant. Although no conclusion could be extracted from the patients who received IVIG, the therapeutic effect of hCG is comparable to that of the other therapeutic regimens, such as allogeneic leukocytes. It was postulated that actual etiology of unknown RSA would be classified as hormonal origin although combined etiologies are common in Korean women.

• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.4
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• pp.261-268
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• 2020

Transformer saturation in full bridge (FB) isolated DC-DC converters is caused by uneven switching speeds and voltage drops in semiconductor devices and mismatched gate signals. In order to prevent transformer saturation, most popular and widely used approach is to insert a capacitor in series with the transformer windings. This study conducts extensive analyses on transformer saturation and the effect of DC blocking capacitors when they are placed in the primary or secondary windings of a transformer. The effect of the DC blocking capacitors is verified in voltage-fed and current-fed FB converters.

• Journal of Biomedical Engineering Research
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• v.11 no.2
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• pp.257-268
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• 1990

A system has been developed for monitoring the effect of neuromuscular blocking frugs and the neuromuscular function during anesthesia and surgery. This system is composed of software and hardware, the latter are nerve stimulator, force transducer, interface board(preamplifier, filter, peripheral input/output) and personal computer (apple ll) , the former are programmed in ASSEMBLY and BASIC language. The nerve stimulator which is controlled by personal computer is capable of delivering single shocks at o.)Hz, train of four at 2Hz and tetanic stimulation at 30, 100, 200Hz. The response, adduction of the thumb, is sensed by the force transducer. The output of the force transducer Is amplified, filtered, converted digital signal and then processed by the per- sonal computer. The personal computer quantia4es twitch and traln of four tesponse and calculates the 74 ratio (Ta/Tl )between the first and fourth response of train of four. This ratio is used to estimate the level of the neuromuscular block. This system has reaserch potential for determining the effect of newer neuromuscular blocking drugs for comparlsion with presently used drugs of alternatively, for delerminig the effects of blocking drugs in altered physilogical states.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.3
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• pp.277-279
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• 2010

This study examined the ultraviolet-A blocking effect and antioxidant activity of Gracilariopsis chorda extract for use as sunscreen agents in cosmetics. The maximum absorbance at ultra violet-A320-330 and transmissivity was 20-80%. The 1,1-diphenyl-2-picrylhydrazyl (DPPH)radical scavenging activity of Gracilariopsis chorda extract was 68?96% and increased with the sample concentration. This indicates that Gracilariopsis chorda extract is a promising natural compound that could be useful as a sunscreen.

• Transactions on Electrical and Electronic Materials
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• v.2 no.3
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• pp.33-37
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• 2001

A vertical trench electrode type EST has been proposed in this paper. The proposed device considerably improves snapback which leads to a lot of problems of device applications. In this paper, the vertical dual gate Emitter Switched Thyristor (EST) with trench electrode has been proposed for improving snab-back effect. It is observed that the forward blocking voltage of the proposed device is 745V. The conventional EST of the same size were no more than 633V. Because the proposed device was constructed of trench-type electrodes, the electric field moved toward trench-oxide layer, and the punch through breakdown of the proposed EST is occurred at latest.

• Journal of the Semiconductor & Display Technology
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• v.8 no.3
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• pp.45-50
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• 2009

Recently, block-based transforms, like discrete cosine transform (DCT), have been widely used in image and video coding standards, but block-based transforms have a weak point with blocking effect. However, the integer lapped orthogonal transform (ILOT) is a tool for block-based coding with bases functions that overlap near blocks, so it has a strong point against blocking effect. Although it has slightly higher arithmetic complexity than the DCT, the coding gain is significantly higher with much less blocking artifacts. This paper introduces the integer lapped orthogonal transforms and discrete cosine transform. And we compare the performance of DCT with ILOT which is proposed a new efficient method for image coding applications.

• The Korean Journal of Community Living Science
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• v.18 no.3
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• pp.391-398
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• 2007

Ginkgo leaves, which have been known as medical materials, were selected as new natural dyes in this study, in which it was examined whether they have the function of UV-blocker or not. Cotton, linen & Hanji(Korean traditional paper) were dyed with Ginkgo. Al, Cr, Cu, Fe and Sn were selected as mordants. UV-blocking rate of dyed samples was measured after dyeing and mordant treatment. The results of this study are as follows. First, most surface color of dyed samples was yellow except that Hanji mordanted with Cu was yellowish red. Second, dyeing repetition had positive correlations with K/S values of cotton ($r=.\;758^{**}$), linen ($r=.\;500^*$) and Hanji ($r=.\;819^{**}$), because K/S values were increased according to dyeing repetition. Third, solar UV-blocking rates had positive correlations with dyeing repetitions (p<0.01), because UV-blocking rates had increased according to dyeing repetition. Fourth, UV-blocking ability of Hanji was highest among samples, as UV-blocking rates of cotton and linen dyed after 3 dyeing repetition were up to 93%, Hanji's values were up to 98%. Therefore, it was proven that Ginkgo extracts used in this experiment as dyestuff have excellent dyeing ability and high UV-blocking ability. It is hoped that this work will lead to further research to confirm the physiological effects when human wear the clothes made from Hanji.

• Membrane Journal
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• v.18 no.1
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• pp.53-64
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• 2008

Fouling behavior of polyethylene capillary membranes was examined by measuring the flux of bentonite colloidal suspensions through the cross flow micro filtration. The membrane fouling was due to the three mechanisms: the cake formation on the membrane surface, the standard pore blocking and the complete pore blocking by particles. These mechanisms were simultaneously responsible for the membrane fouling, being significantly governed by the cake filtration. In the total fouling at $1.0kg/cm^2$ TMP condition, the complete blocking was 3.36%, the standard blocking 3.18% and the cake filtration 96.05%. For 1000 ppm feed solution, the complete blocking was 1.71% compared with the standard blocking of 1.90% and the cake filtration of 96.39%. And 96.14% of the total fouling was generated at the initial period of filtration. The cake filtration effect was larger on $0.34{\mu}m$ pore membrane than on $0.24{\mu}m$ pore membrane. With the increase in cross flow velocity, the component fouling decreased by 10.20%, and the ratio of pore blocking to total fouling increased.