• Korean Journal of Environmental Agriculture
• /
• v.15 no.1
• /
• pp.91-104
• /
• 1996

The viability loss or death of weed seeds buried in soil can be induced by infrared irradiation which has good penetration in moist soil. By using this principle of pre-emergence soil-treatment, the study was carried out to obtain basic information needed to develop the effective weed control method for the production of less polluted agricultural products. An apparatus for irradiating infrared was constructed by using ceramic material with high emissivity. The LPG was used as fuel for producing infrared by heating ceramic material. The soil heated in this study was loam with four levels of moisture contents (0.6, 5.7, 10.7, 15.1 % wb). The temperature distribution was measured at various soil depths when soil with different moisture content was irradiated with infrared for three different times (30, 60, 90 sec). The soil depths with duration time of minimum 3 minutes over $80^{\circ}C$, temperature inducing viability loss of weed seeds, were investigated. When the moisture content of soil was 0.6 and 5.7 % wb, the soil depths which can induce viability loss of weed seeds was greatly increased with increasing irradiation time. However, any depths of soil tested in this study was not reached to the temperature of $80^{\circ}C$ when 30 seconds of irradiation time was applied on soil with moisture content of 10.7 or 15.1 % wb. Generally, the soil depth needed for viability loss of weed seeds was decreased with increasing moisture content of soil. Also, longer irradiation time was required to induce viability loss of weed seeds with increasing moisture content of soil.

• Korean journal of food and cookery science
• /
• v.17 no.6
• /
• pp.542-548
• /
• 2001

Hazard Analysis Critical Control Point(HACCP) is becoming an important component of food safety worldwide. The aim of this study was to investigate comprehensively the education and knowledge level of food service managers on HACCP as well as applying HACCP system to industrial foodservice. Total 247 foodservice managers participated in the survey and 159 responses were used for analysis. The results were as follows: 1) 89% of foodservice managers were educated about HACCP, and 40.9% felt they did fully understand HACCP and 47.8% did half. 2) The score for the implementation of HACCP was in the order of apparatus and facility sanitation, personal sanitation, and time-temperature/etc. sanitation. 3) Foodservice managers who were taught HACCP kept a deep attention to food and personal sanitation, compared with those without education(p＜0.05). However, the education time on HACCP affected conducting safety management. The results suggest that education and understanding of HACCP are positively related, and understanding of HACCP has a positive influence on conducting safety management.

• Korean Journal of Childcare and Education
• /
• v.2 no.1
• /
• pp.65-88
• /
• 2006

This study intended to activate public education, researched and analyzed real conditions of preschool education to know desirable directions of public education and help parents recognize public education. The final purpose is to offer basic materials to reestablish preschool education in the public education system. First, parents' recognition concerning preschool education in the public education system was much different from that of teachers. As for definitions of preschool education as a public education, parents understood that it means 'the nation and self-governing bodies manage aid both the public and private kindergartens', and teachers recognized that it means that 'the nation and self-governing bodies not only found operate public kindergartens but also aid manage educational funds of private kindergartens. Second, the examination of educational environments of kindergartens told that teachers and parents thought that opportunity to enter the kindergarten is not equal for all children in our country, and quality of kindergarten teachers is satisfactory. Also, they thought that curriculums of preschool educational organs have been set well according to children's developmental stages, education quality is different according to preschool education organs' foundation-types. They recognized that facilities and apparatus of preschools are satisfactory, security and neatness of preschools are satisfactory, too. Third, the examination of developmental directions of preschool education as a public education proved following facts; as for foundation-types of kindergartens in the future when promoting preschool education as a public education, parents answered financial support and supervision by the government, teachers answered aid and management of operational fees as well as support for teacher personnel expenses.

• The korean journal of orthodontics
• /
• v.34 no.3 s.104
• /
• pp.253-260
• /
• 2004

Frictional force between the orthodontic bracket and arch wire during sliding tooth movement is related to many factors, such as the size, shape and material of both the bracket and wire, ligation method and the angle formed between the bracket and wire. There have been clear conclusions drawn in regard to most of these factors, but as to the effect of bracket width on frictional force there are only conflicting studies. This study was designed to investigate the effect of bracket width on the amount of frictional forces generated during clinically simulated tooth movement. Three different widths of brackets $(0.018{\times}0.025'\;standard)$ narrow (2.40mm), medium (3.00mm) and wide (4.25mm) were used in tandem with $0.016{\times}0.022'$ stainless steel wire. Three bracket-arch wire combinations were drawn on for 4 minutes on a testing apparatus with a head speed of 0.5mm/min and tested 7 times each. To reproduce biological conditions, dentoalveolar models were designed with indirect technique using a material with similar elastic properties as periodontal ligament (PDL). In addition, to minimize the effect of ligation force, elastomer was used with added resin, which was attached to the bracket to make up for the discrepancies of bracket width. The results were as follows: 1. Maximum frictional force for each bracket-arch wire combination was: Narrow (2.40mm): $68.09\pm4.69gmf$ Medium (3.00mm): $72.75\pm4.98 gmf$ Wide (4.25mm): $72.59\pm4.54gmf$ 2. Frictional force was increased with more displacement of wire through the bracket slot. 3. The ANOVA psot-hoc test showed that the bracker width had no significant effect on frictional force when tested under clinically simulated conditions(p>0.05).

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.58 no.2
• /
• pp.149-160
• /
• 2013

The objective of present study was to simultaneously isolate of isoflavone and soyasaponin compounds from the germ of soybean seeds. Soy germ flours were defatted with hexane for 48h at room temperature, and methanolic extracts were prepared using reflux apparatus at $90^{\circ}C$ for 6h, two times. After extraction, extracts were separated with preparative RP-$C_{18}$ packing column ($125{\AA}$, $55-105{\mu}m$, $40{\times}150mm$), and collected 52 fractions were identified with TLC plate (Kieselgel 60 F-254) and HPLC, respectively. Among the identified isoflavone and soyasaponin fractions, isoflavone fractions were re-separated using a recycling HPLC with gel permeation column (Jaigel-W252, $20{\times}500mm$). Final fractions were air-dried, and the purified compounds of two isoflavones (ISF-1-1, ISF-1-2) and four soyasaponins (SAP-1, SAP-2, SAP-3, SAP-4) were obtained. Two isoflavone compounds (ISF-1-1, ISF-1-2) were acid-hydrolyzed for the identification of their aglycones, and confirmed by comparing with 12 types of isoflavone isomers. While the four kinds of soyasaponins were identified by using a micro Q-TOF mass spectrometer in the ESI positive mode with capillary voltage of 4.5kV, and dry temperature of $200^{\circ}C$. Base on the obtained results, it was conclude that ISF-1-1 is the mixture isomers of daidzin (43.4%), glycitin (47.0%), and genistin (9.6%), but ISF-1-2 is the single compound of genistin (99.8% <). On the other hand, soyasaponin SAP-1 is the mixture compounds of soyasaponin A-group (Aa, Ab, Ac, Ae, Af); SAP-2 is soyasaponin B-group (Ba, Bb, Bc) and E-group (Bd, Be); SAP-3 is soyasaponin B-group (Ba, Bb, Bc), E-group (Bd, Be), and DDMP-group (${\beta}g$); SAP-4 is soyasaponin B-group (Ba, Bb, Bc), E-group (Bd, Be), and DDMP-group (${\beta}g$, ${\beta}a$), respectively.

• Korean Journal of Agricultural Science
• /
• v.5 no.1
• /
• pp.15-28
• /
• 1978

It has been known that the shear strength of soil is an important design parameter for the foundation of structures, the retaining walls, the slope failures and so forth. In this study, the shear test was performed by using the direct shear apparatus under various degree of the moisture content and the density of the sample soils. The results of the study were summarized as follows; 1. The shear strength of soil increased with increase in the dry density of soil, and at the same level of density of the sample the shear strength of soil showed large values on a good grading of the sample. 2. The cohesion of the soil varied directly with the dry density of it, however the internal friction angle of soil was not affected by the dry density of tile sample. 3. The shear strength of sample varied inversly with the moisture content of it, and this phenomenon was apparent on a good grad ing of sample. 4. The cohesion of soil showed maximum value when the moisture content of the soil reached optimum level and the internal friction angle decreased with increase in the moisture content of it. These phenomena were very obvious on a good grading sample, SDC-1. 5. The cohesion of the soil decreased with increase in void ratio of the sample, but the internal friction angle of the sample didn't show such tendency.

• Journal of the Korean Society of Radiology
• /
• v.11 no.5
• /
• pp.335-341
• /
• 2017

Cyclotron is a device that accelerates positrons or neutrons, and is used as a facility for making radioactive drugs having short half-lives. Such radioactive drugs are used for positron emission tomography (PET), which is a medical apparatus. In order to make radioactive drugs from a cyclotron, a nuclear reaction must occur between accelerated positrons and a target. After the reaction, unncessary neutrons are produced. In the present study, radioactivation generated from the collisions between the concrete shielding wall and the positrons and neutrons produced from the cyclotron is investigated. We tracked radioactivated radioactive isotopes by conducting experiments using FLUKA, a type of Monte Carlo simulation. The properties of the concrete shielding wall were comparatively analyzed using materials containing impurities at ppm level and materials that do not contain impurities. The generated radioactivated nuclear species were comparatively analyzed based on the exposure dose affecting human body as a criterion, through RESRAD-Build. The results of experiments showed that the material containing impurities produced a total of 14 radioactive isotopes, and $^{60}Co$(72.50%), $^{134}Cs$(16.75%), $^{54}Mn$(5.60%), $^{152}Eu$(4.08%), $^{154}Eu$(1.07%) accounted for 99.9% of the total dose according to the analysis having the exposure dose affecting human body as criterion. The $^{60}Co$ nuclear species showed the greatest risk of radiation exposure. The material that did not contain impurities produced a total of five nuclear species. Among the five nuclear species, 54Mn accounted for 99.9% of the exposure dose. There is a possibility that Cobalt can be generated by inducive nuclear reaction of positrons through the radioactivation process of $^{56}Fe$ instead of impurities. However, there was no radioactivation because only few positrons reached the concrete wall. The results of comparative analysis on exposure dose with respect to the presence of impurities indicated that the presence of impurities caused approximately 98% higher exposure dose. From this result, the main cause of radioactivation was identified as the small ppm-level amount of impurities.

• Analytical Science and Technology
• /
• v.28 no.6
• /
• pp.436-445
• /
• 2015

Amomi Fructus with anti-oxidative activity was chosen and essential oil was obtained by SDE (simultaneous distillation extraction), and 39 constituents were determined by GC-MS (gas chromatography-mass spectrometry). Major components were camphor, borneol acetate, borneol, D-limonene and camphene. Three solvent extracts such as hexanes, diethyl ether and methylene chloride from Amomi Fructus were obtained. These were analyzed by GC-MS and 4 more constituents were identified in addition to 39 components discovered in essential oil. Five major components such as camphor, borneol acetate, borneol, D-limonene and camphene were also detected, however the relative peak percents of those components were different from those of constituents in essential oil. To estimate the kind and the amount of materials evaporated at certain temperature and conditions from essential oil and solvent extracts, dynamic headspace apparatus was used and materials evaporated and trapped at certain conditions were analyzed by GC-MS. Recovery yield of SDE method from Amomi Fructus was measured by using camphor and standard calibration solution of camphor methanol solution and, the yield was 82.0%. Content of Hg was measured by mercury analyzer and contents of Cd, Pb, Cr, Mn, Co, Ni, Cu and Zn in Amomi Fructus, essential oils and solvent extracts were determined by ICP-MS (Inductively coupled plasma-mass spectrometer). Pb, Cd and Hg were measured in the concentration of 0.72 mg/kg, <0.10 mg/kg and 0.0023 mg/kg, respectively and these were below permission level of purity test. Contents of Mn, Cu and Zn in Amomi Fructus were 213 mg/kg, 8.29 mg/kg and 31.0 mg/kg, respectively and which were relatively higher than other metals such as Cr, Co and Ni. Metals such as Mn (0.65 ~ 9.08 mg/kg), Cu (1.16 ~ 4.40 mg/kg) and Zn (1.10 ~ 3.80 mg/kg) in essential oil and solvent extracts were detected. At this point it is not clear that the metals were cross-contaminated in the course of treating Amomi Fructus or metals were contained in Amomi Fructus. The influence evaluation toward biological model study of these metals in essential oil and solvent extracts will be needed.

• Journal of Periodontal and Implant Science
• /
• v.24 no.2
• /
• pp.219-237
• /
• 1994

The ultimate goal of clinical periodontal therapy is to achieve regeneration of a healthy connective tissue reattachment. Conventional therapy including scaling, root planing, gingival curettage, gingivectomy and flap procedures of various types results primarily in repair rather than regeneration of the periodontium. In order for periodontal regeneration to occur, progenitor periodontal ligament cells must migrate to the denuded root surface, attach to it, proliferate and mature into an organized and functional fibrous attachment apparatus. Polypeptide growth factors belong to a class of potent biologic mediators which regulate cell differentiation, proliferation, migration and metabolism. Insulin-like growth factor-I (IGF- I ) of these factors appear to have an important role in periodontal wound healing and bone formation. The purpose of this study is to evaluate the effects of IGF- I on the periodontal ligament cells to use as a regeneration promoting agent of periodontal tissue. Human periodontal ligament cells were obtained from periodontal tissue explants culture of the first premolar tooth extracted for the orthodontic treatment. Cells were cultured in Dulbecco's modified Eagle medium(DMEM) with 10% fetal bovine serum. Fourth to seventh passage cells were plated in 24 well tissue culture plates and medium changed to serum-free medium prior to addition of growth factors. Cell proliferation was measured by the incorporation of $[^3H]-thymidine$ into DNA, Protein synthesis was determined by measurement of $[^3H]-proline$ incorporation into collagenase-digestible protein(CDP) and noncollagenous protein(NCP) according to the method of Peterkofsky and Diegelmann (1971), And alkaline phosphatase activity was measured as one parameter of osteoblastic differentiation. The results were as follows : The DNA synthetic activity was increased in a dose-dependent manner with IGF- I except for 0.1ng/ml concentration of IGF- I At the concentration of 10, 100ng/ml, IGF- I significantly increased the DNA synthetic activity(P<0.05) The total protein, collagen and noncollagen synthesis was increased in a dose-dependent manner with IGF- I except for 0.1ng/ml concentration of IGF- I. At the concentration of 1, 10, 100ng/ml, IGF- I significantly increased the total protein, collagen and noncollagen synthesis activity(P<0.95, P<0.001). The % of collagen was not effected according to the concentration of IGF- I. The alkaline phosphatase activity was increased in a dose-, time-dependent manner with IGF- I (10, 100ng/ml). In conclusions, the present study shows that IGF- I has a potentiality to enhance the DNA synthesis of periodontal ligament cells with including the increase of the total protein and collagen synthetic activity. The use of IGF- I to mediate biological stimulation of periodontal ligament cells shows promise for future therapeutic applications.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.29 no.1
• /
• pp.45-58
• /
• 2013

The purpose of this study was to analyze the area of occlusal contact points using visual method. One subject was selected who had Angle Class I, normal dentition, without dental caries, periodontal disease and temporomandibular disorders. Forty times PVS impressions were taken and 10 pairs casts were fabricated using dental super hard stone. After mounting the casts with customized loading apparatus, 78.9kg/f force was loaded as a maximum biting force. In T-Scan method, occlusal contact points measurement was repeated twice. Then, using Photoshop program (Adobe photoshop CS3, Adobe. San Jose, USA), the pixels which indicated occlusal contact points by color was recognized, and the distribution of recognized pixels were calculated to area. In Add picture method, polyether bite material applied to the occlusal surface of the casts. Then, the image of the translucent areas was recorded and classified $0{\sim}10{\mu}m$, $0{\sim}30{\mu}m$, $0{\sim}60{\mu}m$ area by the amount of transmitted light. To acquire occlusal surface, the numbers of pixels from the photograph of the contact area indicated cast converted to $mm^2$. The mean occlusal contact area by two methods was statistically analyzed (paired t-test). Part of the red and pink area in T-Scan image were almost equivalent to the $0{\sim}10{\mu}m$, $0{\sim}30{\mu}m$, $0{\sim}60{\mu}m$ area in Add picture image. The distribution of occlusal contact points were similar, but the average area of occlusal contact points was wider in T-scan image (P<.05). Pink and red area in T-scan image was wider than $0{\sim}10{\mu}m$, $0{\sim}30{\mu}m$ area in Add picture image (P<.05), but similar to $0{\sim}60{\mu}m$area in Add picture image (P>.05). Occlusal contact points in T-scan image did not indicate real occlusal contact points. Occlusal contact areas in T-scan method were enlarged results comparing with those in Add picture method.