• Journal of Mechanical Science and Technology
• /
• v.16 no.12
• /
• pp.1693-1701
• /
• 2002

The intermittent spray characteristics of a multi-hole and a single-hole diesel nozzle were experimentally investigated. The hole number of the multi-hole nozzle was 5, and the hole diameter of the 5-hole and the single-hole nozzle was the same as d$\_$n/=0.32 ㎜ with the constant hole length to diameter ratio(l$\_$n//d$\_$n/=2.81). The droplet diameters of the spray, including the time-resolved droplet diameter, SMD (Sauter mean diameter) and AMD (arithmetic mean diameter) , injected intermittently from the two nozzles into the still ambient were measured by using a 2-D PDPA (phase Doppler particle analyzer). Through the time-resolved evolutions of the droplet diameter, it was found that the structure of the multi-hole and the single-hole nozzle spray consisted of the three main parts : (a) the leading edge affected by surrounding air. and composed of small droplets; (b) the central part surrounded by the leading edge and mixing flow region and scarcely affected by the resistance of air, (c) the trailing edge formed by the passage of the central part. The SMD decreases gradually with the increase in the radial distance, and the constant value is obtained at the outer region of the radial distance (normalized by hole diameter) of 7-8 and 6 for the 5-hole and single-hole nozzle, respectively. The SMD along the centerline of the spray decrease shapely with the increase in the axial distance after showing the maximum value near the nozzle tip. The SMD remains the constant value near the axial distance(normalized by hole diameter) of 150 and 180 for the 5-hole and the single-hole nozzle, respectively.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.8 no.2
• /
• pp.289-295
• /
• 1998

Used gasoline engine oils(UGEO) are carcinogenic in long term studies and capable of increasing the number of carcinogen-DNA adducts in short term studies when dermally applied to mice. The carcinogenic risk of UGEO has been attributed to the concentration of polycyclic aromatic hydrocarbons(PAH) which accumulate in the lubricating system during the combustion of gasoline. When dermally exposed to UGEO, the use of hand cleanser was commonly recommended for removing it. But generally workers who dermally exposed oils, use kerosene as cleaner which make skin trouble. During this study, female mice aged 4-6 weeks were utilized to evaluate the efficiency of kerosene, as solvent-based cleanser, following dermal exposure to UGEO. DNA adduct were detected at skin and lung tissues by using the $^{32}P$-postlabeling method. Washing with cleansers were done at two different interval times following dermal application of UGEO. The total DNA adducts in skin and lung tissues were statistically significantly increased in positive control groups, and of which the total adduct level in skin tissues was statistically significant higher than those in lung tissues(p=0.005). When washing kerosene, the DNA adduct level in skin tissues was statistically significantly decreased(p=0.0001). But DNA adducts in lung tissue was statistically increased(p=0.0039), and that washed at 8hr post exposure was more severly increase(p<0.05). The slope of regression between DNA adducts of lung between skin tissues was 1.0802. In conclusion, skin cleaning with kerosene facilitates passage of carcinogens to the lungs of animals dermally treated with used gasoline engine oils(UGEO).

• Journal of Korean Elementary Science Education
• /
• v.28 no.1
• /
• pp.55-66
• /
• 2009

The purpose of this study is to assist understanding the integrated subjects and to obtain implications required on the actual operation of curriculum by analyzing content elements and basic inquiry activities in the revised "wise lift" curriculum 2007. The result of this study is as follows. First, the formation of elements in contents of "wise life" deals with the passage of time based on changing seasons, myself and family in the 1st grade and the concept of space based on home and a village in the 2nd grade. Six main subjects and twelve activity subjects are presented per each grade. Second, number of activity subjects and content elements are reduced as compared with 7th curriculum so that the responsibility of operating classes based on activities is reduced and the purpose of rationalizing contents is somewhat fulfilled. Third, eliminating a relevant domains decisively when presenting the activity subjects assures the identification and purpose as the integrated subject focused on inquiry activities. Fourth, the result of analyzing the course-relevance on content elements shows that the allotment per each domain and course is less considered but the relevance of social studies is higher regardless of non-course characteristics as the integrated subject. Fifth, according to the component ratio of basic inquiry activities, 'Observing' and 'Debating' were presented as the most essential activities, and 'Measuring' and 'Making' were relatively low. By considering characteristics of course requiring balanced and various experiences of inquiry activities, additional discussions are required on appropriateness of the component ratio. Sixth, 'Observing' was increased and 'Debating' and 'Making' were decreased on the main activities in this revised curriculum as compared with 7th curriculum.

• Ocean and Polar Research
• /
• v.30 no.4
• /
• pp.497-507
• /
• 2008

With the reduction of tidal currents by the closing of the Saemangeun 4th dyke, sedimentary environments on the Gunsan tidal flat, the nearest inner flat from the 4th dyke, has been severely changed, which might affect macrobenthic assemblages on the habitats. In order to investigate changes in macrobenthic community structure on Gunsan tidal flat, field surveys were seasonally conducted at seven stations from April 2002 to November, 2005. Sedimentary facies on the study area were shifted into muddominant facies. The fine sediment has been greatly deposited on the tidal flat with accumulation of organic materials after closing the water passage of 4th dyke section. These drastic variations in environments gave rise to change in macrobenthic community structure. Since the closure of the 4th dyke, the number of species of macrobenthos has gradually decreased. And the filter feeders and sand-favored species such as Urothoe convexa, Macrophthalmus dilatatus, Umbonium thomasi, and Mactra veneriformis have been replaced by the deposit feeders such as Macrophthalmus japonicus and Ilyoplax pingi. MDS ordination based on Bray-Curtis similarity from forth-root transformed species abundance data showed that the macrobenthic communities have passed through three succession stages from 2002 to 2005. During the third stage of 2005 opportunistic species such as Prionospio japonica, Heteromastus filiformis and Sinocorophium sinensis increased in population on the tidal flat.

• Journal of the Korean Society for information Management
• /
• v.32 no.3
• /
• pp.317-340
• /
• 2015

This study clarified the knowledge structure of international collaboration in psychiatry based on analyzing networks in order to construct cooperation networks for international collaboration in psychiatry in South Korea. The result of analysis of knowledge structure at a state-level is as follows. First, this study found that the rate of collaboration for five years is high as 89.97%. Moreover, this study investigated the change of rate of collaboration and international collaboration according to the passage of time, and ascertained that while the rate of international collaboration has increased, Second, this study examined the trend of research on collaboration between Asian countries, and found that collaboration between Asian countries is on a low level. Third, the country (or group) that the number of papers of international collaboration and the value of centrality are the highest is EU-28. The result of analysis of knowledge structure at a research output-level is as follows. this study analyzed the correlation of centrality with research output, and found that positive correlation exists in the three indicators of centrality, and a country with high centrality has good research output.

• Asian Journal of Atmospheric Environment
• /
• v.6 no.1
• /
• pp.41-52
• /
• 2012

Particulate sulfate in $PM_{2.5}$, sulfur dioxide ($SO_2$) and size-segregated aerosol particle number concentrations were measured at a site ($32^{\circ}19'N$, $129^{\circ}59'E$) on the southwestern Japan coast from 5 March to 10 April, 2010. Results show frequent episodic increases of sulfate and $SO_2$. Compared to the average concentration of sulfate $4.4{\pm}2.7\;{\mu}g\;m^{-3}$ in the whole observation period, episodic sulfate reached $10.5-20.1\;{\mu}g\;m^{-3}$. The variation of sulfate always synchronized with aerosol particles in the size range of $0.1-0.5 {\mu}m$, indicating the episodic sulfate was a consequence of the increase of the sub-micron particles. $SO_2$ did not have remarkable increase in any episodes of sulfate increase. During the passage of low pressure systems which loaded Asian dust in postfrontal air, concentrated sulfate appeared right behind the front but before dust arrival, suggesting the dominance of dust-free particulate sulfate. Weather and backward trajectory analyses revealed that air parcels with high sulfate passed eastern and northeastern China or Korean peninsula before arriving at the site. In contrast, those with high $SO_2$ passed an active volcano, Mt. Sakurajima, about 100 km in the south, suggesting the $SO_2$ was more likely from the volcanic emission. The ratio of sulfate to total sulfur compounds $({SO_4}^{2-})/({SO_4}^{2-}+SO_2)$ was 0.31-0.89 in continentally originated air while was 0.25-0.43 in the air having passed the volcano, showing more efficient conversions of $SO_2$ to sulfate in the air from the continent. The close dependence of the conversion on humidity in the continentally originated air was confirmed.

• Journal of Astronomy and Space Sciences
• /
• v.22 no.3
• /
• pp.293-310
• /
• 2005

We made a revised catalogue for reliable records of meteor outbursts that were recorded in Korean, Japanese, and Chinese chronicles. In order to avoid the effects of both Earth's precession and perihelion shift, we introduced a new time-coordinate of records, or the number of days elapsed within the sidereal year of the record for a given origin of time or the perihelion passage time of the you 2000. We added nineteen new records of meteor showers that are wrongly classified i, individual meteors in a Chinese archive. We found that the ${\eta}-Aquarids,$ the Perseids, the Orionids, and the Leonids have been active during the last two millennia. Due to the change of time-coordinate, the oldest record of each long-lasting meteor shower has been slightly corrected. We discuss that these long-lasting meteor showers belong to the Halley-type comets.

• Journal of Pharmacopuncture
• /
• v.11 no.1
• /
• pp.201-209
• /
• 2008

Objectives : This study was designed to make beneficial proposal for clinical application on some of the most common disorders treated by Oriental medicine by analyzing treatment process and prognosis. Methods : Number of peculiar attributes pertaining to a specific disorder were analyzed and based on those attributes, patterns associated with process and prognosis were interpreted in reference with classical literatures. Results : 1. Factors which can influence the progression and prognosis include time of onset, intensity of symptoms, course of passage, effects of risk factors, condition of the patient's righteous qi(正氣), accuracy of differential diagnosis made by the practitioner, accuracy of treatment methods, and other unexpected external influences. 2. Correlation between the condition of disorders and treatment progression is closely associated with proper treatment procedures and performances. The time of onset and intensity play critical roles in the treatment process and prognosis and showed pattern tendency with mutual interactions. 3. When there is complication of various disorders, it is ideal to give priority to more urgent illness and take care of moderate illness later. If there isn't any correlation between disorders, treat them in the order of acute to chronic disorders. The approach is reversed when disorders are related, treating in the order of most chronic to most acute. 4. In a case of complication of various disorders, depending on the disorder being acute or chronic, intensity, and accuracy of treatments, either a domino effect or gradual fade out of symptoms were witnessed. 5. The concept of "Five Evils Theory" according to Nan Jing(Difficult Classic) is essential in grasping disease progression due to interrelationships between zangfu organs. Conclusions : Predicting of disease process and prognosis for vast array of disorders treated by Oriental medicine is a very difficult task, yet evaluating the disorder's peculiar properties and influential factors resulted in few principles which can be effectively applied into clinical applications.

• Korean Journal of Veterinary Research
• /
• v.38 no.2
• /
• pp.386-393
• /
• 1998

The study was performed to investigate the histological findings and the appearances of positive cells by immunohistochemical methods using proliferating cell nuclear antigen (PCNA) antibody and apoptotic kit in diethylnitrosamine (DEN) -induced rat liver cancer model. Forty four male rats (Sprague Dawley), initially 5 to 6 weeks of age and 120 to 150gm in body weight were continuously were given with water containing 0.01% DEN for 13 weeks and 3~6 rats per week were randomly sacrified at intervals of a week from 8 weeks to 17 weeks. The interlobular connective tissues in the rat livers were proliferated at early 8 weeks. The vaccuolated or fatty degenerated liver cells were focally distributed and then widely distributed with the passage of weeks and the liver cells with large vacuoles tended to be crowded in focal areas, and the liver cells in some lobules were transformed into small or eosinophilic polyhedral large cells. The hepatocellular carcinoma and the cholangiocarcinoma were simultaneously developed in same liver and tended to be markedly developed after 12 weeks but the development of carcinoma in some livers at same week were less or more advanced as 3~5 week intervals. The regions with more number of positive cells by PCNA antibody or apoptotic kits in livers were ranked as following order ; small hepatocellular carcinoma regions, cholangiocarcinoma regions, trabecular or acinar type carcinoma regions, and large liver cell regions. The numbers of the positive cells by PCNA antibody were more numerous than those by apoptotic kit. So these findings suggested that the volumes and weights of the livers were increasing by more many proliferating of carcinoma cells on the above ordered regions.

• Journal of Oral Medicine and Pain
• /
• v.40 no.3
• /
• pp.89-95
• /
• 2015

All living organisms have a biological clock that orchestrates every biological process and function, and this internal clock operates following a circadian rhythm. This biological clock is known to influence various clinical indicators such as blood pressure and body temperature. Also, the fluctuation of signs and symptoms of diseases including pain disorders are affected by circadian rhythm. It has been reported that the pain intensity of various somatic and neuropathic pain disorders show unique pain patterns that depend on the passage of time. The generation of pain patterns could be explained by extrinsic (e.g., physical activity, tactile stimulation, ambient temperature) and also intrinsic factors (neural and neuroendocrine modulation) that are related to the circadian rhythm. It is important to recognize and identify the individual pain pattern in pain therapy to approve treatment outcome. Moreover, chronotherapeutics which considers pain patterns and pharmacokinetics in context of the circadian rhythm could produce greater analgesia in response to medication. However, only a limited number of studies handle the issue of pain patterns according to circadian rhythm and chronotherapeutics in the orofacial region. The present review intends to reflect on the most recent and relevant data concerning the bidirectional relation between pain disorders of the orofacial region and circadian patterns.