• Restorative Dentistry and Endodontics
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• v.21 no.1
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• pp.360-365
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• 1996

The purpose of this study was to evaluate the changes in the degree of conversion on a composite resin surface following heat treatment and mylar strip finishing. The effects of the time interval between the light-curing and heat-curing process were also evaluated. The composite resin surface which had been covered with a coverglass showed a lower conversion rate than the surface from which a layer of $500{\mu}m$ was ground away. The composite resin surface was definitely affected by oxygen during the heat curing process when it had not been insulated. When the composite resins were heat cured after 3 days of storage following the light curing process, the increased in the degree of conversion through heatcuring was limited.

• Journal of computational fluids engineering
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• v.12 no.3
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• pp.13-19
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• 2007

A numerical simulation on the heat transfer and flow field was carried out to improve the performance of the shell and tube heat exchanger. The steady incompressible 3-D Navier-Stokes solution is obtained with the actual operational condition and geometry of the heat exchanger. Based on this study, it is noted that the present geometry of the heat exchanger causes poor heat transfer since the air inside shell does not flow through the tube bundle, but around it. The enhancement of the heat transfer can be achieved by the variation of the design factor like the sealing strip located on the top/bottom and middle of the baffle, but it causes the increasement of the pressure drop. In this paper, the effects of the location and size of the sealing strips and flow rate through the heat exchanger on the heat transfer and pressure drop are studied.

• Korean Management Science Review
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• v.27 no.2
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• pp.55-66
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• 2010

In Korea, deap-sea fishing industry plays an important role in a food industry. However, it is in a difficult situation because of the more competitive business environment. Therefore, there is a need to restructure the deap-sea fishing industry by scraping superannuated ships. This paper is designed to present scrap programs for deap-sea fishing industry of Korea. We performed ratio analysis to evaluate financial performance of fishing companies and then applied a mixed integer programming (MIP) model to identify optimal schedule for scraping. The results of the financial ratio analysis indicates that it is legible to provide governmental aid to Atlantic trawl, Northern Pacific trawl, and Indian ocean trawl with minimum required rate of return (MRR) of 3%, and the Atlantic strip fishing industry is qualified to receive the governmental aid with MRR value of 5%. Furthermore, by applying the MIP model to develop scrap planning, we demonstrate how our model can be used to restructure the deap-sea fishing industry of Korea.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.38 no.8
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• pp.650-657
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• 1989

The conversion efficiency of an ozone generator can be significantly improved by modifying the discharge electrode of a helical strip line rod-to-cylinder type ozone generator to a pyramid-project-embossed rod, and by using a pulse corona discharge. Parametric studies have been carried out to obtain optimum values of peak pulse voltage, pulse forming capacitance, feeder cable and ozone generator capacitance, interelectrode spacing and corona tip density of ozone generator, and feed air flow rate and temperature. The generated ozone concentration was very dependent upon the value of pulse forming capacitance, feeder cable and ozone generator capacitance, and corona tip density. Maximum conversion efficiency was obtained with a pulse forming capacitance of about 500pF, 75pF matched feeder cable and ozone generator, and a corona tip density of 16mm. When operated at optimum values, ozone yield of 79, 99, 80 g/KWh for the different interelectrode type ozone generators tested were obtained, which are approximately 30% higher than that of an industrial ozone generator.

• Journal of Welding and Joining
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• v.19 no.3
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• pp.267-273
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• 2001

In this study, welding phenomena involved in formation of penetrators during high frequency electric resistance welding were investigated. High speed cinematography of the process revealer that a molten bridge between neighboring skelp edges forms at apex point and travels along narrow gap toward to welding point at a speed ranging from 100 to 400 m/min. The bridge while moving along the narrow gap swept away oxide containing molten metal from the gap, providing oxide-free surface for a forge-welding at upsetting stand frequency of the budge formation, travel distance and speed of the bridge were affected by the heat input rate into strip. The travel distance and its standard deviation were found to have a strong relationship with the weld defect density. Based on the observation, a new mechanism of the penetrator formation during HF ERW process is proposed.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.10
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• pp.890-896
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• 2008

Sheet metal forming is one of the most useful and important method in manufacturing of the autobody panels because of the excellent production rate. The objectives of sheet metal forming processes are getting a desired geometrical shape of products with good quality, low cost and reasonable lead time. In this paper, we examined the validity of finite element method analysis on the automobile FRT-PLR-L/R stamping process by using the lancing engineering method. Lancing is a press operation in which a single-line cut or slit is made on part way across the strip stock, without removing any metal. As a result, it has shown that the proper lancing engineering method could prevent fracturing by improving sheet metal flow.

• YAKHAK HOEJI
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• v.39 no.5
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• pp.471-479
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• 1995

The recombinant human epidermal growth factor(DWP 401) was investigated on the pharrnacological actions. DWP 401 had no effects on the hexobarbital-induced sleeping time, locomotor activity, rotarod test, body temperature, analgesic action and anticonvulsant action in mice. It also had no influences on the isolated tracheal muscle and ileum of guinea-pig, isolated uterus and fundus strip of rats. Slight hypotensive action with effect on respiration was revealed at a dose of 8 g/kg i.v. of DWP 401 in rabbits. DWP 401 exhibited a weak inhibitory action of glucose tolerance in normal rats, significantly lowered the blood glucose contents in adrenalectomized rats at .a concentration of 160 g,/kg, and produced a significant inhibitory effect on leucocyte migration in CMC-pouch of rats at a concentration of 32 g/rat. Furthermore, DWP 401 showed a significant decrease on gastric juice volume and acidity. However. DWP 401 had no intestinal propulsion rate and influence on urine excretion.

• The Korean Journal of Pharmacology
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• v.11 no.2
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• pp.19-27
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• 1975

Haloperidol, a butyrophenone, was synthetized by Janssen and introduced for the treatment of psychosis. Although structurally different from the phenothiazines, the butyrophenones share many of their pharmacological properties, such as inhibition of conditioned avoidance response, blocking effect of amphetamine reaction, producing catalepsy, antishock effect and protection against the lethal effects of catecholalmines. Chlorpromazine can lower the arterial blood pressure through its adrenergic blocking activity, its direct effect in relaxing vascular smooth muscle, its direct effect in depressing the myocardium and its action in a complex manner on the central nervous system. In the case of haloperidol, however, was not clarified the mechanism of lowering the blood pressure. The present paper describes the effects of haloperidol on cardiovascular system to investigate the mechanisms of its actions on the arterial blood pressure. The results are followings; 1. In anesthetized cats, intravenous administration of haloperidol and chlorpromazine in the dose of 0.1mg/kg produced a slight decrease in the blood pressure, which followed by complete recovery within $30{\sim}60$ minutes. In the dose of 3mg/kg, however, both produced an abrupt and marked decrease of the blood pressure, which followed by delayed recovery. 2. Haloperidol in the dose ranges of 0.1mg to 3.0mg/kg tended to produce the heart rate slowing in the cats, while chlorpromazine has no effect on the rate. 3. Following administration of haloperidol or chlorpromazine, epinephrine reversal in the arterial blood pressure was observed in the cat, however the responses of norepinephrine and acetylcholine were little affected. 4. In the isolated rabbit atrium the contractility was depressed by haloperidol in the doses over 0.5mg per 100ml, but the rate was not affected. In contrast, the epinephrine-induced contractility was not depressed after haloperidol treatment. However, the increased rate of atrium by epinephrine was partially blocked after haloperidol. 5. In the isolated rabbit aortic strip, epinephrine-induced contraction was blocked by haloperidol. With the above results, it may be concluded that the hypotensive effect of haloperidol was largely due to ${\alpha}$-adrenergic blocking properties and the direct effect in depressing the myocardium as well as its action on central nervous system.

• Journal of Korean Society of Forest Science
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• v.97 no.5
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• pp.540-546
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• 2008

Enrichment planting has been used as one of the promising restoration techniques to accelerate the natural restoration process of secondary forests or logged-over forests in Myanmar, The objectives of this study were to examine the growth performances of two commercial species such as Teak (Tectona grandis Linn f.) and Padauk (Pterocarpus macrocarpus Kurz) in response to different canopy opening treatments and to examine the suitability of these species in enrichment planting activities for the restoration of degraded tropical forests in Myanmar. In this study, split plot design was applied, and three levels of canopy openings were experimented. The survival rate and height growth of two species were measured four times with 6 month interval. The root collar diameter (RCD) was also measured in the last assessment. Although the survival rate of seedlings was not significantly different among the three treatments (p>0.05) as well as between two species (p>0.05) for all consecutive measurements, height (p<0.05) and RCD were significantly different (p<0.001) among the treatments, T. grandis seedlings thrived best under complete canopy opening (i.e., 5 m width canopy opening with strip-clear cutting) while P. macrocarpus seedlings under partial canopy opening (without felling of marketable tree species). Because this study is concerned with only for young stage of seedlings, continuous assessment and follow-up tending activities are needed to verify the species suitability and optimum width of canopy opening for enrichment planting activities in restoration of degraded forests of Myanmar.

• Korean Journal of Environment and Ecology
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• v.8 no.1
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• pp.74-77
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• 1994

To examine the effects of gibberelin treatment on seed germination of five Viola species - Viola variegata, Viola dissecta var, chaerophylloides, Viola collina, Viola hirtipes and Viola manshrica - in Wonju district, pretreated seeds of five species were sowed on Jiffy strips with mixed soil(sand： peat moss： perlite： vermiculite, 1:1:1:1, v/v) in 25, May 1994. Seeds were soaked in 5, 25, 50ppm gibberelin solution and ground water during 24 hours. Seed germination rate was measured and compared among species and treatments. Seed germination rate of Viola hirtipes was differed higly significant among pretreatments, but those of other species did not significant at 5of level. In general GA$_3$pretreatment raised seed germination rate of 5 Viola species, and proper concentration of GA$_3$was 25~50ppm.