• Journal of Veterinary Clinics
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• v.24 no.3
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• pp.384-391
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• 2007

This study was conducted to clarify the effects of the Korean raisin (Hovenia dulcis Thunb) extracts and polyherbal extracts consisted of 6 types herbal extracts including HDT (HDTmix) on $CCl_4$ induced organ damages. Extracts were prepared by autoclave ($121^{\circ}C$, 15 psi, 3 hours) and filtered with nylon cloth and filter paper then freezing dried. Male Sprague-Dawley rats $(200^{\circ}{\ae}20g)$ were used as experimental groups, which were divided into 5 groups; intact control group (100 mg/kg), $CCl_4$ dosing group (100 mg/kg), $CCl_4$ dosing after HDT extract dosing group (100 mg/kg), $CCl_4$ dosing after HDTmix dosing group (100 mg/kg), Silymarin dosing group (5 mg/kg) after all test articles were orally dosed once a day for 28 days. They were sacrifiled under ether anesthesia. HDT extracts and HDTmix dramatically inhibits the $CCl_4$ intoxicated hepato/nephropathies with immuno-suppress changes on the spleen. They showed more dramatical protective effects on most of specific organs compared to that of Silymarin 5 mg/kg except for hepatoprotective effects in which, quite similar effects were detected. In addition, HDT extracts showed synergic effects with other types of herbal extracts because HDTmix showed more favorable protective effects on the all specific organs showing $CCl_4-related$ histopathological changes compared to HDT extracts.

• Proceedings of the KIEE Conference
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• 1998.07e
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• pp.1852-1854
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• 1998

In this paper, we design an effective and secure optical subscriber loop to offer multimedia service to apartment residents. The designed subscriber loop has the following properties. First, a proxy is connected to HDT(Host Digital Termination) which is a switching device, in order to effectively support multimedia services. Second, a scheduler of HDT dynamically manages bandwidth allocation and reallocation to a subscriber considering the situation of communication traffic. Finally, three alternations are used for safety.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.5595-5600
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• 2012

This paper is to review and study about the crystallization nucleating agent to improve the heat-resistance properties of poly(lactic acid). Four sub-micron sized nucleating agents, metallic salts of 2,2'-methylene bis(4,6-di-tert-butylphenol), were prepared and used as a crystallization nucleating agent. Thermal and mechanical properties of polymer compounds were investigated by DSC, HDT and UTM. As the results, While the heat-resistance properties of the polymer compound samples were increased linearly with the contents of nucleating agent as well as their smaller size. Among them, the highest heat-resistance property of compound was observed with 2 wt% of MPZ2. HDT values of PL98Z2 compound was $116^{\circ}C$ at 0.455Mpa.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.3
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• pp.1671-1676
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• 2015

A unique crystallization behavior of poly(L-lactide)(PLLA)/poly(D-lactide)(PDLA) stereocomplex(SC) was observed when a PLLA/PDLA blend was subjected to the specific melting conditions. Therefore, we tried to blend PLLA and PDLA at overall composition to form PLA stereocomplexes. Moreover, impact modifier and reinforcement materials such as talc and glass fiber added to enhance the mechanical and thermal properties such as impact strength and heat distortion temperature(HDT). As a result, we got one representative result, one composite recipe with HDT $115^{\circ}C$. For more economic technology, we tried to blend PLLA and Polypropylene at overall composition and we got another representative result which could be applied to current PP/talc composites and ABS materials. The core technology of this might be the well dispersion of glass fibers into the matrix resin such as PP, PLLA and impact strength modifier.

• Journal of Adhesion and Interface
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• v.9 no.2
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• pp.16-23
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• 2008

In this study, novel waste wool/polypropylene NFRPs (natural fiber reinforced polymer composites), which are constituted with waste wool discarded as industrial scrap during manufacturing processes of woven fabrics and general purpose thermoplastic polypropylene (PP), were fabricated by means of compressionmolding and their mechanical and thermal properties were characterized. The mechanical properties of PP resin were significantly improved by an introduction of waste wool to PP. In particular, as the loading of waste wool was 50 vol% in the NFRP, the flexural strength of the NFRP was increased about 20%, the flexural modulus about 143%, the tensile strength about 76%, and the tensile modulus about 90% in comparison with each of PP control. In addition, the maximum value of the heat deflection temperature (HDT) obtained with the NFRP was $138^{\circ}C$ at a 50 vol% loading of waste wool. This is $21^{\circ}C$ higher than the HDT of PP control. The result here suggests that waste wool be a potential candidate for a reinforcing material of thermoplastic matrix resins.

• Korean Chemical Engineering Research
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• v.46 no.6
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• pp.1081-1086
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• 2008

QDs-LEDs(quantum dot light emitting device) should contain well-organized arrays of QDs on an electron transport layer. Thin films of CdSe/ZnS core-shell QDs were successfully fabricated on $TiO_2$ substrates by using PDMS stamp and micro contact printing method. 2-Carboxyethylphosphonic acid(CAPO) and 1,6-hexanedithiol(HDT) were employed as molecular linkers in assembling CdSe/ZnS core-shell QDs with high-density and uniform array. The CAPO increased the binding strength between the QDs and the substrates, and the HDT induced the strong inter-particle attractions of assembled QDs. The assembling properties of QDs thin films were characterized by SEM, AFM, optical microscope and photoluminescence spectroscope(PL).

• Journal of Veterinary Clinics
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• v.24 no.3
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• pp.400-405
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• 2007

This study was performed to investigate the therapeutic effects of Hovenia dulcis Thunberg (HDT) and HDTmix extracts on the biochemical analysis, histopathology and histomorphometry of liver and kidney in carbon tetrachloride $(CCl_4)$ administrated rats. Extract was prepared by autoclave ($121^{\circ}C$, 15 psi, 3 hours) and filtered with nylon cloth and filter paper then freezing dried. In blood chemistry analysis, HDTmix group, aspartate aminotransferase and alanine aminotransferase were significantly (p<0.01) decreased compared to the $CCl_4$ group, on 3rd day, respectively. In histologic and histomorphometry analysis, the $CCl_4-related$ hepatopathies and nephropathies were dramatically decreased (3rd, 5th day), and well corresponded to the histopathological changes significantly (p<0.01) decreases of degenerative regions, degenerative cells and glomeruli were detected in liver and kidney with significantly decreases of $CCl_4$ group. HDTmix group, quite similar effects on the liver and kidney were observed compared to that of HDT extracts group but more favorable efficacies were detected especially HDTmix also inhibit the hepatopathies (1 day), in which HDT extract does not showed any inhibit effects.

• The Korean Journal of Physiology
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• v.24 no.1
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• pp.51-65
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• 1990

The purpose of the present study was to examine the hemodynamic responses, especially in arterial and skin blood flows, in conjunction with the changes of plasma catecholamine levels as an indirect marker of adrenergic tone during the early stage of head-down tilt (HDT), and to evaluate the early physiological regulatory mechanism in simulated weightlessness. Ten mongrel dogs, weighing8\;{\sim}\;14\;kg, were intravenously anesthetized with nembutal, and postural changes were performed by using the tilting table. The postural changes were performed in the following order: supine, prone, HDT $(-6^{\circ}C)$ and lastly recovery prone position. The duration of each position was 30 minutes. The measurements were made before, during and after each postural change. The arterial blood flow $({\.{Q}})$ at the left common carotid and right brachial arteries was measured by the electromagnetic flowmeter. Blood pressure (BP) was directly measured by pressure transducer in the left brachial artery. To evaluate the peripheral blood flow, skin blood flow $({\.{Q}})$ was calculated by the percent changes of photoelectric pulse amplitude on the forepaw, and skin temperature was recorded. The peripheral vascular resistance (PR) was calculated by dividing respective mean BP values by ${\.{Q}}$ of both sides of common carotid and brachial arteries. Heart rate (HR), respiratory rate (f) and PH, $Po_{2},\;Pco_{2}$ and hematocrit of arterial and venous blood were also measured. The concentration of plasma epinephrine and norepinephrine was measured by radioenzymatic method. The results are summarized as follows: Tilting to head-down position from prone position, HR was initially increased (p<0.05) and BP was not significantly changed. While ${\.{Q}}$ of the common carotid artery was decreased (p<0.05) and PR through the head was increased, ${\.{Q}}$ of the brachial artery was increased (p<0.05) and PR through forelimbs was decreased. ${\.{Q}}$ of the forepaw was initially increased (p<0.05) and then slightly decreased, on the whole revealing an increasing trend. Plasma norepinephrine was slightly decreased and the epinephrine was slightly increased. f was increased and arterial pH was increased (p<0.05). In conclusion, the central blood pooling during HDT shows an increased HR via Bainbridge reflex and an increased ${\.{Q}}$ of the forepaw and brachial ${\.{Q}}$, due to decreased PR which may be originated from the depressor reflex of cardiopulmonary baroreceptors. It is suggested that the blood flow to the brain was adequately regulated throughout HDT $(-6^{\circ}C)$ in spite of central blood pooling. And it is apparent that the changes of plasma norepinephrine level are inversely proportional to those of ${\.{Q}}$ of the forepaw, and the changes of epinephrine level are paralleled with those of the brachial ${\.{Q}}$.

• The Journal of the Korea Contents Association
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• v.9 no.1
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• pp.81-88
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• 2009

In the previous work, we presented HDTS for locating logical errors in Java programs. The HDTS locates an erroneous method at an execution tree using an algorithmic program debugging technique and locates a statement with errors in the erroneous method using a step-wise program debugging. The technique can remove the unnecessary statements and nodes in debugging using a program slicing technique at the execution tree. So HDTS reduces the number of program debugging. In this paper, we design HDTS system for debugging java programs. We define small subset of Java language and design the translator that translates java source codes and the virtual machine that runs java programs. We design GUI(Graphical User Interface) for debugging.

• Polymer(Korea)
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• v.34 no.6
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• pp.574-578
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• 2010

In this study, the caprolactone modified hydroxy acrylates (CHAs) were synthesized by ring-opening reaction of caprolactone and 2-hydroxyethyl acrylate (2-HEA) as initiator. Also, the caprolactone modified urethane acrylate (UA) oligomers were synthesized by condensation reaction of previously synthesized CHAs, 2-hydroxyethyl acrylate (2-HEA) and hexamethylene diisocyanate trimer (HDT). Using the hydroxy number of CHAs, the molecular weights of the CHAs were calculated easily and their molecular weight was similar to the theoretical molecular weight of them. The viscosity of UA oligomers decreased as increasing a content of CHA in the UA oligomer. Cure films were prepared from UA oligomer, reactive diluents, and UV initiator to investigate their physical properties. The thermal stability and color difference on high temperature for the cured film were improved as increasing the crosslinking density. Their surface hardness was also increased as increasing crosslinking density of the cured films, but their elongation at break was decreased.