• Restorative Dentistry and Endodontics
• /
• v.34 no.5
• /
• pp.406-414
• /
• 2009

The purpose of this study was to examine the effect of hydrogen peroxide at different application time and concentrations on the microtensile bond strength of resin restorations to the deep and the pulp chamber dentin. A conventional endodontic access cavity was prepared in each tooth, and then the teeth were randomly divided into 1 control group and 4 experimental groups as follows: Group 1, non treated; Group 2, with 20% Hydrogen peroxide ($H_2O_2$); Group 3, with 10% $H_2O_2$; Group 4, with 5% $H_2O_2$; Group 5, with 2.5% $H_2O_2$; the teeth of all groups except group 1 were treated for 20, 10, and 5min. The treated teeth were filled using a Superbond C&B (Sun medical Co., Shiga, Japan). Thereafter, the specimens were stored in distilled water at $37^{\circ}C$ for 24-hours and then sectioned into the deep and the chamber dentin. The microtensile bond strength values of each group were analyzed by 3-way ANOVA and Tukey post hoc test(p < 0.05). In this study, the microtensile bond strength of the deep dentin (D1) was significantly greater than that of the pulp chamber dentin (D2) in the all groups tested. The average of microtensile bond strength was decreased as the concentration and the application time of $H_2O_2$ were increased. Analysis showed significant correlation effect not only between the depth of the dentin and the concentration of $H_2O_2$ but also between the concentration of H202 and the application time(p < 0.05), while no significant difference existed among these three variables(p > 0.05). The higher $H_2O_2$ concentration, the more opened dentinal tubules under a scanning electron microscope(SEM) examination.

• Current Research on Agriculture and Life Sciences
• /
• v.4
• /
• pp.87-94
• /
• 1986

This study was performed in order to contemplate their correlations between physical and mechanical properties of the marine clays which were collected from main harbors in Korea. The results obtained are as follows: 1. Most of the soils in experimental districts consist of CH. CL. and ML. and they are considered to be still proceeding. 2. The equations of the relationship between compression index and liquid limit are as, follows: CH : $C_c=0.0137$ (LL-22.60) CL : $C_c=0.0123$ (LL-14.64) 3. The relationship between compression index and initial void ratio appears that the higher the plasticity, the easier the slope of the regression line. The equations are as follows : CH : $C_c=0.431$ ($e_o-0.504$) CH : $C_c=0.471$ ($e_o-0.235$) ML : $C_c=0.641$ ($e_o-0.393$) 4. The equations of the relationship between compression index and natural water content are as follows: CH : $C_c=0.0133$ ($W_n-28.27$) CL : $C_c=0.0225$ ($W_n-23.56$) ML : $C_c=0.0106$ ($W_n-16.42$) 5. The relationship between initial void ratio and natural water content, and compression index is highly positive correlation and the equations are as follows : CH : $C_c=0.301$ ($e_o+0.017W_n-1.05$) CL : $C_c=0.141$ ($e_o+0.0567W_n-1.054$) ML : $C_c=0.421$ ($e_o+0.0214W_n-1.121$) 6. The equations of the relationship between initial void ratio and liquid limit, and compression index are as follows : CH : $C_c=0.36$ ($e_o+0.08LL-0.819$) CL : $C_c=0.269$ ($e_o+0.026LL-0.929$) 7. The cohesion of marine clays is no concerned with the increment of depth. The equations of relationship between cohesion and unconfined compression strength are as follows. CH : qu=1.896C+0.0107 CL : qu=1.849C+0.04.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.14 no.2
• /
• pp.102-117
• /
• 2009

This study was carried out to investigate the extent to which benthic environment of Ulsan Bay was disturbed by organic materials and trace metals from the megacity and industrial complex. Field survey for benthic environment and macroinvertebrate community was seasonally conducted from February to November 2006 at nine stations covering the inside and outside of the bay. TOC was on average 1.7% while four (As, Cu, Pb, Zn) out of seven trace metals measured exceeded the Effects Range Low (ERL) in most of the stations. Total number of species sampled was 199 and mean density was 4,578 ind./$m^2$, both of which were greatly dominated by the polychaetes. Dominant species were Aphelochaeta monilaris (22.6%), Ruditapes philippinarum (17.1%), Magelona japonica (12.2%), Lumbrineris longifolia (9.9%) and their distribution was ruled by the difference in the benthic environmental condition of each station. From the multivariate analyses, four stational groups were identified: northern part of the bay, middle and lower part of the bay, the intersection of Taewha River and Gosa stream and outside of the bay. As a result, the community heterogeneity of inner bay was much more greater than that of outer bay. SIMPER analysis showed that four groups were represented by R. philippinarum-Capitella capitata, A. monilaris-Balanoglossus carnosus, Sinocorophium sinensis-Cyathura higoensis and M. japonica-Ampharete arctica, respectively. Spatio-temporal changes of macroinvertebrate communities in Ulsan Bay were closely related to those of depth, mean grain size and organic content, and Zn was also a meaningful factor in that context.

• Explosives and Blasting
• /
• v.9 no.1
• /
• pp.3-13
• /
• 1991

The cautious blasting works had been used with emulsion explosion electric M/S delay caps. Drill depth was from 3m to 6m with Crawler Drill ${\phi}70mm$ on the calcalious sand stone (soft -modelate -semi hard Rock). The total numbers of test blast were 88. Scale distance were induced 15.52-60.32. It was applied to propagation Law in blasting vibration as follows. Propagtion Law in Blasting Vibration $V=K(\frac{D}{W^b})^n$ were V : Peak partical velocity(cm/sec) D : Distance between explosion and recording sites(m) W : Maximum charge per delay-period of eight milliseconds or more (kg) K : Ground transmission constant, empirically determind on the Rocks, Explosive and drilling pattern ets. b : Charge exponents n : Reduced exponents where the quantity $\frac{D}{W^b}$ is known as the scale distance. Above equation is worked by the U.S Bureau of Mines to determine peak particle velocity. The propagation Law can be catagorized in three groups. Cubic root Scaling charge per delay Square root Scaling of charge per delay Site-specific Scaling of charge Per delay Plots of peak particle velocity versus distoance were made on log-log coordinates. The data are grouped by test and P.P.V. The linear grouping of the data permits their representation by an equation of the form ; $V=K(\frac{D}{W^{\frac{1}{3}})^{-n}$ The value of K(41 or 124) and n(1.41 or 1.66) were determined for each set of data by the method of least squores. Statistical tests showed that a common slope, n, could be used for all data of a given components. Charge and reduction exponents carried out by multiple regressional analysis. It's divided into under loom over loom distance because the frequency is verified by the distance from blast site. Empirical equation of cautious blasting vibration is as follows. Over 30m ------- under l00m ${\cdots\cdots\cdots}{\;}41(D/sqrt[2]{W})^{-1.41}{\;}{\cdots\cdots\cdots\cdots\cdots}{\;}A$ Over 100m ${\cdots\cdots\cdots\cdots\cdots}{\;}121(D/sqrt[3]{W})^{-1.66}{\;}{\cdots\cdots\cdots\cdots\cdots}{\;}B$ where ; V is peak particle velocity In cm / sec D is distance in m and W, maximLlm charge weight per day in kg K value on the above equation has to be more specified for further understaring about the effect of explosives, Rock strength. And Drilling pattern on the vibration levels, it is necessary to carry out more tests.

• (The) Research of the performance art and culture
• /
• no.18
• /
• pp.413-444
• /
• 2009

This paper is an analysis of stage and performance elements for the ceremonial procedures and dance featured in bongsudang-jinchan, a feast celebrating the 60th birthday of Hyegyeong-gung Hongssi (Crown Princess Hong of Hyegyeonggung), the mother of King Jeongjo, which took place in Hwaseong haegung palace in 1795. The primary sources used are data on bongsudangjinchan recorded in Wonhaeng-eulmyojeongriuigwe, Jeongjo-sillok, Hongjae-jeonseo, pictorial sources such as Folding Screens of Hwaseong-neunghaeng and Hwaseong Ilgi, which is a journal in Korean by Yi Hui-pyeong. A court ceremony to offer music, dance, flowers, and food, as well as wine and poetry which express the sentiments of chung (fidelity) and hyo (filial piety) was considered a national ceremony and has constituted a unique musical culture during the 500 years of Joseon dynasty. However, after the fall of Joseon dynasty, ceremonial music and dance, which have been organically linked within the overall symbolic system of ye (courtesy), became scattered to become independent 'pieces.' As a result, all of their philosophy, principles, and the time-space interpretation of court music and dance became greatly reduced, leaving only the artistic expression and formal structure of the music and dance to become emphasized. Since the 1990s, there has been many research and events aiming to re-create the court ceremonial tradition, resulting in the increase of the related performance activities. This is especially true with bongsudang-jinchan, which is now being performed on modern stage in various forms. However there are still many problems to be solved, such as the issue of re-creating and restoring the original, and the question of artistic value found in the traditional pieces. Until now, much focus has been paid to the outer re-construction of uiju document as recorded in Wonhaeng-eulmyo-jeongriuigwe. On the other hand, there lacked an in-depth study which analyzes the stage situation and performance elements. Therefore in this paper, after focusing on the stage structure and performance elements, it is concluded that bongsudang-jinchan, the only court feast to be held in Haeng gung, not only consists of the fundamental aspects of court performance principle as 'governing through ye and ak (music),' but also served as an important occasion to bring together the sovereign and the subject. Bongsudang-jinchan had features of both naeyeon (feast for ladies) and oeyeon (feast for gentlemen). It minimized the use of screens and allowed every guest to enjoy food, music, and dance together, but provided a separate tent for foreign guests, maintaining the ideal balance between equality and distinction among different gender and social status. A screen symbolizing the venue for the feast is placed for all of the government officials. The king then pronounces the beginning of the banquet in which the ideal of gunsin-dongyeon (king and officials dining together) is realized. This indicates that bongsudang-jinchan, compared to other court ceremonies that emphasize the principle of yeak (courtesy and music), focuses more on the spirit of harmony and rapprochement. The king played a more active role in bongsudang-jinchan than in any other royal feasts. Examples as recorded in uiju documents are; Jeongjo's conversation with his retainers after the 7th wine, king's bestowing of food and flowers to the officials, writing his own majesty's poems with regard to the festival, and asking the retainers to write replying poems. All these played an important part in making the occasion more rich, extensive, and meaningful. Moreover, as analysis of the structure of orchestral music and court dance featured in bongsudang-jinchan shows, it was like any other court banquet in that it employed minimal use of extravagance in movements and conversation. However, the colors and tonal texture used in the music and dance were more brilliant in this case. Compared to other banquets that took place before king Jeongjo, the dance style was more diverse, which included some of the latest additions. There were past performances arranged anew. Noteworthy are; the incorporation of "Seonyurak (Boat Dance)" and "Geommu (Sword Dance)," traditionally used for local officials and civilians feast, to suit the court taste; and the use of saenghwang (mouth organ), which was a rising instrument in pungnyubang (literati's private salon), for "Hakmu (Cranes Dance)." This especially indicates the nature of the 'open structure' pursued by the court banquets at the time, which strove to break away from the traditional rules and customs and accept something new.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.7
• /
• pp.255-261
• /
• 2020

This study was undertaken to evaluate the growth, body shape and carcass cutting yield traits of Duroc (D) and crossbred (Duroc×Pietrain×Pietrain; DPP) pigs. A total of 147 D and 101 DPP pigs were used for analyzing the growth trait, whereas 16 D and 16 DPP pigs were evaluated for carcass yields. Backfat thickness (BF) and average daily feed intake (ADFI) were significantly higher in D (14.07±0.24 mm, 2,101 g) than in DPP (12.69±3.25 mm, 1,909 g) (p <0.001). Moreover, D exhibited significantly higher body shape traits including body height (BH), chest depth (CD) and chest width (CW), as compared to DPP pigs (p <0.001). No differences were observed for body length (BL) between the two strains. Analysis of the carcass cutting yield traits determined for D and DPP were in the order: ham (HM; 31.17% and 33.43%), belly (BY; 23.40% and 19.55%), and picnic shoulder (PS; 16.54% and 16.87%), respectively. Then, HM showed a difference of 2.26% P with D(31.17%) and DPP(33.43%), while BY showed a difference of 3.85% P with D(23.40%) and DPP(19.55%). Taken together, our results indicate that DPP has a better feed efficiency than D, and therefore has the potential to increase the production of low-fat pork, targeting consumers having a high preference who have opted for a healthy lifestyle. These results can be used as basic data for developing an ideal pig breed.

• Ocean and Polar Research
• /
• v.26 no.4
• /
• pp.581-594
• /
• 2004

CREAHS II carried out an intensive hydrographic survey covering almost entire East Sea in 1999. Hydrographic data from total 203 stations were released to public on the internee. This paper summarized the results of water mass analysis by OHP (Optimum Multiparameter) method that utilizes temperature, salinity, dissolved oxygen, pH, alkalinity, silicate, nitrate, phosphate and location data as an input data-matrix. A total of eight source water types are identified in the East Sea: four in surface waters(North Korea Surface Water, Tatar Surface Cold Water, East Korean Coastal Water, Modified Tsushima Surface Water), two intermediate water types (Tsushima Middle Water, Liman Cold Water), two deep water types (East Sea Intermediate Water, East Sea Proper Water). Of these NKSW, MTSW and TSCW are the newly reported as the source water type. Distribution of each water types reveals several few interesting hydrographic features. A few noteworthy are summarized as follows: The Tsushima Warm Current enter the East Sea as three branches; East Korea Coastal Water propagates north along the coast around $38^{\circ}N$ then turns to northeastward to $42^{\circ}N$ and moves eastward. Cold waters of northern origin move southward along the coast at the subsurface, which existence the existence of a circulation cell at the intermediate depth of the East Sea. The estimated volume of each water types inferred from the OMP results show that the deep waters (ESIW + ESPW) fill up ca. 90% of the East Sea basins. Consequently the formation and circulation of deep waters are the key factors controlling environmental condition of the East Sea.

• Journal of Gastric Cancer
• /
• v.6 no.2
• /
• pp.109-113
• /
• 2006

Purpose: Various minimally invasive surgical techniques, such as an endoscopic mucosal resection and a laparoscopic gastrectomy, are becoming common practice for some cases of early gastric cancer (EGC) defined in terms of the depth of invasion being limited to the mucosa or submucosa. However, there are rare cases of early gastric cancer with massive lymph-node metastasis. Materials and Methods: From 6 university hospitals of Korea, 2,772 EGC cases were resected during the various period of analysis (1,432 cases of mucosal cancer and 1,340 of submucosal cancer). Results: As control data, we used the data from a single institute, CHA University Hospital. There were nine cases of early gastric cancer (9/2,772, 0.32%) with N3 lymph node metastasis defined by more than 15 lymph nodes being metastasized according to the UICC-TNM classification (pT1N3, stage IV). Two cases were mucosal cancer (2/1,432, 0.1 4%), and seven cases were submucosal cancer (7/1,340, 0.52%). Metastasized lymph nodes varied in number from 18 to 52. There were three male and six female patients with a mean age of 57. This is a totally reversed sex ratio compared to the usual gastric cancer or EGC. Among the total of 9 EGC patients, there were 5 who had superficial spreading carcinomas with surface areas larger than $25\;cm^2$. This is a significantly higher proportion compared to the general EGC population. When we compared the tumor size according to the LN status, the N3 group was definitely larger than the other groups. 78% of the pT1N3 cases showed lymphatic invasion, which is very high compared to the 4.7% in general EGC cases. Among the 9 cases, 6 patients had too short a follow-up period to evaluate the correct prognosis, but there was one patient with a non-curative resection and two patients with early recurrence. Although the sample size is small and the follow-up period is short, we can expect a very poor prognosis when we consider the common prognosis of EGC that is widely known and accepted. Conclusion: From these results, we can a conclude that the risk factors for pT1N3 gastric cancer are female patients, submucosal invasion, larger tumor size, and lymphatic invasion. However rare, the existence of pT1N3 gastric cancer needs to be taken into consideration, especially during the diagnosis. Furthermore, minimally invasive treatment for EGC needs to be chosen with great precaution. Since the prognosis of pT1N3 gastric cancer is expected to be poor, aggressive adjuvant chemotherapy may be necessary. (J Korean Gastric Cancer Assoc 2006;6:109-113)

• Journal of Nutrition and Health
• /
• v.47 no.4
• /
• pp.258-267
• /
• 2014

Purpose: The current study was designed to investigate the relationship of dietary calcium and riboflavin and their main dietary source (milk and dairy products) with the risk of periodontitis using data from 2007 to 2010 Korea National Health and Nutrition Examination Surveys. Methods: A total of 1,690 adults aged ${\geq}40$ years were included. We used results of dental examination regarding all sextant information on probing depth of at least two index teeth, nutritional assessment by a single 24-hour dietary recall, and demographic and medical information. The periodontitis group was defined as those who had 3-4 points, and the normal group was defined as those who had 0 points of Community Periodontal Index at all locations of six examination sites using a probe. Results: Using multiple logistic regression analysis, after adjustment for age, body mass index, energy intake, income, smoking, and alcohol drinking, we found an inverse relationship between consumption of dairy products and risk for periodontitis (OR: 0.465, 95% CI: 0.224-0.964) and between dietary riboflavin intake more than the estimated average requirements and risk for periodontitis (OR: 0.535, 95% CI: 0.300-0.954) in males. Conclusion: Adequate intake of milk dairy products and riboflavin may be recommended for prevention of periodontitis in the Korean male population.

• Journal of dental hygiene science
• /
• v.17 no.6
• /
• pp.487-494
• /
• 2017

There is little evidence on the effects of environmental tobacco smoke (ETS) on prevalence of periodontal disease. The aims of this study were to explore the trends of prevalence of periodontal disease and types of exposure to smoke, including ETS according to the survey year, identify factors affecting periodontal disease, and compare the effect size of periodontal disease between active smokers and secondhand smokers. Data on 11,643 individuals were obtained from the fourth and fifth Korean National Health and Nutritional Examination Surveys. Information on exposure to ETS at home and work was self-reported. Severity of periodontal disease was evaluated using the community periodontal index. A multivariate logistic regression analysis was performed to model periodontal disease using types of smoking and the survey year. Overall, the prevalence of periodontal disease was 26.0% (n=3,029) and about 9% of the study population were secondhand smokers. The prevalence of periodontal disease among smokers was significantly increased according to smoking types by year. Active smokers showed a statistically significant adjusted odds ratio (aOR) for having periodontal disease except in the year 2007, whereas secondhand smokers had significant associations only in 2010 (aOR, 1.68; 95% confidence interval, 1.05 to 2.70) compared to non-smokers. For secondhand smokers, the statistical relationship of predicting periodontal disease was weaker than that of active smokers. However, ETS should separately be considered as an important risk factor for periodontal disease. This study suggested the need for further investigation of the impact of ETS on prevalence of periodontal disease using in-depth research designs and objective measurements for assessing periodontal disease and ETS.