• Nuclear Engineering and Technology
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• v.39 no.5
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• pp.603-616
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• 2007

Roy Huddle, having invented the coated particle in Harwell 1957, stated in the early 1970s that we know now everything about particles and coatings and should be going over to deal with other problems. This was on the occasion of the Dragon fuel performance information meeting London 1973: How wrong a genius be! It took until 1978 that really good particles were made in Germany, then during the Japanese HTTR production in the 1990s and finally the Chinese 2000-2001 campaign for HTR-10. Here, we present a review of history and present status. Today, good fuel is measured by different standards from the seventies: where $9*10^{-4}$ initial free heavy metal fraction was typical for early AVR carbide fuel and $3*10^{-4}$ initial free heavy metal fraction was acceptable for oxide fuel in THTR, we insist on values more than an order of magnitude below this value today. Half a percent of particle failure at the end-of-irradiation, another ancient standard, is not even acceptable today, even for the most severe accidents. While legislation and licensing has not changed, one of the reasons we insist on these improvements is the preference for passive systems rather than active controls of earlier times. After renewed HTGR interest, we are reporting about the start of new or reactivated coated particle work in several parts of the world, considering the aspects of designs/ traditional and new materials, manufacturing technologies/ quality control quality assurance, irradiation and accident performance, modeling and performance predictions, and fuel cycle aspects and spent fuel treatment. In very general terms, the coated particle should be strong, reliable, retentive, and affordable. These properties have to be quantified and will be eventually optimized for a specific application system. Results obtained so far indicate that the same particle can be used for steam cycle applications with $700-750^{\circ}C$ helium coolant gas exit, for gas turbine applications at $850-900^{\circ}C$ and for process heat/hydrogen generation applications with $950^{\circ}C$ outlet temperatures. There is a clear set of standards for modem high quality fuel in terms of low levels of heavy metal contamination, manufacture-induced particle defects during fuel body and fuel element making, irradiation/accident induced particle failures and limits on fission product release from intact particles. While gas-cooled reactor design is still open-ended with blocks for the prismatic and spherical fuel elements for the pebble-bed design, there is near worldwide agreement on high quality fuel: a $500{\mu}m$ diameter $UO_2$ kernel of 10% enrichment is surrounded by a $100{\mu}m$ thick sacrificial buffer layer to be followed by a dense inner pyrocarbon layer, a high quality silicon carbide layer of $35{\mu}m$ thickness and theoretical density and another outer pyrocarbon layer. Good performance has been demonstrated both under operational and under accident conditions, i.e. to 10% FIMA and maximum $1600^{\circ}C$ afterwards. And it is the wide-ranging demonstration experience that makes this particle superior. Recommendations are made for further work: 1. Generation of data for presently manufactured materials, e.g. SiC strength and strength distribution, PyC creep and shrinkage and many more material data sets. 2. Renewed start of irradiation and accident testing of modem coated particle fuel. 3. Analysis of existing and newly created data with a view to demonstrate satisfactory performance at burnups beyond 10% FIMA and complete fission product retention even in accidents that go beyond $1600^{\circ}C$ for a short period of time. This work should proceed at both national and international level.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.7
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• pp.445-453
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• 2012

An investigation for removal of 1-indanone (1-ID), which were commonly produced from the biological and/or chemical treatment and natural weathering of the PAHs-contaminated soils, via oxidative transformation mediated by birnessite in the presence of various phenolic mediators is described. This study also examines the potential effect of the natural occurring substance humic acid (HA) on the oxidative transformation. The experiment was carried out in aqueous phase as a batch test (10 mg/L 1-ID, 0.3 mM phenolic mediators, $1.0g/L\;{\delta}-MnO_2$, at pH 5). All of the 11 tested phenoilic mediators belong to the group of natural occurring phenols and are widely used as model constituents of humic substances. From the results of HPLC analysis, it is demonstrated that 1-ID was not reactive to birnessite itself, but it can be effectively removed in birnessite-mediated cross coupling reactions in the presence of the phenolic mediators. The percent removals of 1-ID after 2 day incubation were ranged from 9.2 to 71.2% depending on the phenolic mediators applied. The initial rate constant ($K_{int}$, $hr^{-1}$) values for the 1-ID removals obtained from the pseudo-first-order kinetic plots also widely ranged from 0.18 to 15.0. Results of the correlative analysis between the removal efficiencies and structural characteristics of phenolic mediators indicate that the transformation of the 1-ID was considerably enhanced by the addition of electron-donating substituents (e.g., -OH, $-OCH_3$) at the benzne ring, and much less enhanced by the addition of electron-withdrawing substituents (e.g., -COOH, -CHO). The presence of HA showed that removal efficiencies of 1-ID in the birnessite-phenolic mediator systems decreased with increasing HA concentrations. However at low concentration of HA (< 2 mg/L), it caused some enhancement in the removals of 1-ID as compared to the control.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.3
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• pp.426-434
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• 2011

In order to increase the use of rice, ginseng Garaedduks and Topokki were made and the physicochemical and sensory properties were investigated. Topokki and Garaedduks were added with 0, 1, 3 and 5% ginseng powder and stored at $20^{\circ}C$ for 48 hours. The moisture contents were not different to the increasing amount of ginseng powder and increasing storage time for 48 hours. The moisture content of Garaedduks for control and 5% added ginseng powder were 48.08% and 49.62%, respectively. The L value in color of uncooked ginseng Garaedduk decreased according to the added amount of ginseng powder, and the b value in color increased significantly according to the added amount of ginseng powder and during 48 hours storage at $20^{\circ}C$. Textural analysis, measured using a texture analyzer, of Garaedduk revealed that hardness, cohesiveness, chewiness decreased significantly and adhesiveness increased according to the added amount of ginseng powder. In sensory evaluation, 5% ginseng Garaedduk (uncooked, cooked) scored higher in overall acceptability than those of the other samples. In cooking properties, water absorption and solid contents increased according to the added amount of ginseng powder. Therefore, Garaedduk containing 5% ginseng powder was the most preferable. These results implied that the degree of retrogradation of ginseng Garaedduk might be low due to its high dietary fiber content.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.1
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• pp.135-140
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• 2014

Pre-storage ultra-violet (UV) light treatment on fresh produce is known to inactivate the contaminated microorganisms, activate the defense system, and delay ripening extending the shelf life. As UV light emitting diode (LED) becomes available at a relatively low price, continuous or intermittent UV treatment during chilled storage is possible in a container or package. This study attempted an in situ UV LED treatment on fresh produce stored under a refrigerated container in order to see its potential in the fresh produce storage and further optimize its application conditions. The effect of in-container UV LED irradiation on the quality preservation of shredded carrots was investigated in the air and modified atmosphere (MA) conditions. Two sets of experiment with Escherichia coli inoculation and with natural microbial flora in the air (two 30 minute on-off cycles of 1 $diode/dm^2$ per day at a location above 2 cm) showed a clear and significant effect of the UV LED irradiation on the suppression of microbial growth: 280 nm was the most effective by maintaining a lower microbial count by at least 0.5 log (CFU/g) throughout the 6 day storage period. The carotenoids content of shredded carrots subjected to UV LED treatment at 365 and 405 nm in the air was higher than that of the control shredded carrots. In MA condition of $O_2$ of 1.2~4.3% and $CO_2$ of 8.4~10.6% being indifferent with LED wavelengths, 280 nm UV LED irradiation was also effective in inhibiting the microbial growth. While there was no observed difference in the carotenoids content between untreated and UV LED-treated shredded carrots in MA, UV LED irradiation at 365 and 405 nm was slightly better in DPPH radical scavenging activity. The use of UV LED in storage container or package seems to give the benefits of preserving the microbial and nutritional qualities of minimally processed fruits and vegetables.

• Korean Chemical Engineering Research
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• v.50 no.3
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• pp.492-498
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• 2012

In this study, hydrodynamics such as solid circulation rate and voidage in the desulfurizer and the reaction characteristics of Zn-based solid sorbents were investigated using lab-scale high pressure and high temperature desulfurization process. The continuous HGD (Hot Gas Desulfurization) process consist of a fast fluidized bed type desulfurizer (6.2 m tall pipe of 0.015 m i.d), a bubbling fluidized bed type regenerator (1.6 m tall bed of 0.053 m i.d), a loop-seal and the pressure control valves. The solid circulation rate was measured by varying the slide-gate opening positions, the gas velocities and temperatures of the desulfurizer and the voidage in the desulfurizer was derived by the same way. At the same gas velocities and the same opening positions of the slide gate, the solid circulation rate, which was similar at the temperature of $300^{\circ}C$ and $550^{\circ}C$, was low at those temperatures compared with a room temperature. The voidage in the desulfurizer showed a fast fluidized bed type when the opening positions of the slide gate were 10~20% while that showed a turbulent fluidized bed type when those of slide gate were 30~40%. The reaction characteristics of Zn-based solid sorbent were investigated by different desulfurization temperatures at 20 atm in the continuous operation. The $H_2S$ removal efficiency tended to decrease below the desulfurization temperature of $450^{\circ}C$. Thus, the 10 hour continuous operation has been performed at the desulfurization temperature of $500^{\circ}C$ in order to maintain the high $H_2S$ removal efficiency. During 10 hour continuous operation, the $H_2S$ removal efficiency was above 99.99% because the $H_2S$ concentration after desulfurization was not detected at the inlet $H_2S$ concentration of 5,000 ppmv condition using UV analyzers (Radas2) and the detector tube (GASTEC) which lower detection limit is 1 ppmv.

• KSBB Journal
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• v.25 no.6
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• pp.572-576
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• 2010

Biological products, such as live varicella vaccine, are composed of biological substances derived from biological organisms. It is very difficult to identify these biologics' characteristics by analysis of simple physical and chemical methods alone. So the reference material is essential in order to evaluate the quality of bilogics. The 1'st national standard for varicella live vaccine was manufactured, established in 2002 and 2003, and have been used for the manufacturer's quality control and national lot release since then. As the lack of its availability and the decrease of its stability, this study was initiated by National Institute of Food and Drug Safety Evaluation (NiFDS) in 2008 to manufacture and establish the 2nd national standard for varicella live vaccine. The candidate material was manufactured from one of domestic manufacterers and the joint research of the NiFDS and manufacturers of varicella live vaccine was conducted to estimate of the reliable virus content. In the collaborative study, 3 laboratories including NiFDS performed the virus content test more than 7 times and all assay results were statistically analyzed. The mean coefficient of variation (CV) was 1.24%, and the geometric mean titre (GMT) variation range of each laboratory was low. On the basis of the results of this study, the candidate material of 2nd national standard for varicella live vaccine was assigned a potency of 4.26 log10 pfu/0.5 mL, when reconstituted in 0.7 mL.

• Korean Journal of Plant Resources
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• v.21 no.5
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• pp.368-373
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• 2008

In order to investigate the effects of low temperature pretreatment of floral bud and plant growth regulators on anther-derived callus and shoot differentiation, anthers were cultured on 1/2 MS medium supplemented with 2,4-D, NAA, BA and TDZ. This plant depends on the plant growth regulators, for these anthers couldn't respond on 1/2 MS medium without plant growth regulators. 2,4-D was a prerequisite substance in this experiment, especially 52.6% of callus formation on MS medium with 2.0mg/L 2,4-D alone. However, the optimum medium was on 1/2 MS medium with 0.1 mg/L 2,4-D and 1.0mg/L BA for continuous growth and shoot differentiation from the anther. Calli derived from on MS medium with 2.0mg/L 2,4-D transferred to the 1/2MS medium with TDZ and BA. TDZ were less superior to BA, only one anther could produce shoot on MS media with 1.0mg/L TDZ. On the other hand, when the calli transferred to the medium with 3.0mg/L BA, adventitious shoots were proliferated, subsequently, regenerated shoots elongated from the embryogenic calli. After floral buds of one week before anthesis were incubated at $5^{\circ}C$ refrigerator for eight or fifteen days, anthers seperated from floral buds were cultured on 1/2MS medium supplemented with 0.1mg/L 2,4-D and 1.0mg/L BA. Callusing and shoot differentiation on anthers from treated at $5^{\circ}C$ for eight days were more effective than those of fifteen days or control.

• Journal of The Korean Society of Grassland and Forage Science
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• v.24 no.1
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• pp.11-20
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• 2004

This pot experiment was conducted to investigate the effects of combined micronutrient application($T_1$;control, $T_2$; Fe, $T_3$; Fe＋Mn, $T_4$: Fe＋Mn＋Cu, $T_5$ ; Fe＋Mn＋Cu＋Zn, $T_6$ ; Fe＋Mn＋Cu＋Zn＋Mo, $T_7$ ;Fe＋Mn＋Cu＋Zn＋Mo＋B) on forage performance of pure and mixed cultures of orchardgrass and white clover. This 4th part was related to the changes in the contents of micronutrients(Fe, Mn, Cu, Zn, Mo, and B) in forages. The results obtained are summarized as follows: 1. General differences have been showed in the contents of micronutrients based on the treatments, forage species, pure/mixed culture, cutting order, and additional fertilization, especially N. Compared to pure culture, orchardgrass showed relatively high contents of Mn and Zn, and low contents of B and Fe in mixed culture. White clover, however, tended to be exactly opposed to the above trends. The contents of Cu and Mo did not show any differences between pure and mixed cultures. 2. In relative comparison, the $T_7$ influenced negatively on the contents of Cu, Zn, and Mo in orchardgrass. The $T_7$ also influenced negatively on the contents of Mo in white clover. However, the $T_7$ influenced positively on the contents of Mn in orchardgrass, and also influenced positively on the contents of Fe, Mn, and Cu in white clover. Because of the antagonism between Fe and Mn, the Fe contents in both forages were significantly decreased by the $T_3$. Under the various conditions, the differences among Fe contents tended to be more significant in white clover than in orchardgrass. 3. At the $T_6$ and $T_7$, the Mo contents in both forages tended to be relatively high. The Mo contents, however, were somewhat decreased by the $T_7$ 7/. The Mo-toxicity, which was caused by the high Mo-contents, tended to be diminished, and was likely to be prevented by the optimum B/Mo ratio and B application($T_7$ ).

• Korean Journal of Health Education and Promotion
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• v.18 no.1
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• pp.109-125
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• 2001

The purpose of this study was to provide the basic data for establishing school education environment protection measures, on the basis of comparing and analyzing the realities and students' recognition degree of the environment and hygiene around the middle and high schools located in the rural areas. These study data were investigated by the self-administered questionnaires, taking as subject the 805 students in the middle and high schools located rural areas. And the results were as follows: First, as the result of having investigated the distribution degree of harmful environment within the purification zone around schools, it was found out that students responded: within the purification zone around the middle school, there were cartoon rooms (46.2％), electronic game rooms (45.9％), and singing rooms (45.0％). within the purification zone around the high school, there were electronic game rooms (46.3％), singing rooms (42.3％), billiard halls (41.4％), PC rooms (40.1 ％), and Soju-room (35.2％). Secondly, as having analyzed student's recognition degree of the harmful environment around the school, it was found out that middle school students responded that sexual utensils-treating shops (3.74 points) were most harmful, and next corrupted bathhouses (3.52 points), and Soju-room (3.47 points), and high school students also responded relating to harmfulness in a similar sequence. Thirdly, in case of students' recognition degree of the harmful environment around the school according to general characteristics, 1) girl students had a higher ratio of recognition that the environment around the school was harmful than boy students (p〈0.001). 2) groups of students whose living standard was high had a higher ratio of recognition that the environment around the school was harmful than groups of students whose living standard was low (p〈0.05). 3) groups of students whose school was located near the park or the residential street had a higher degree of recognition that the environment around the school was harmful than groups of students whose school was located near the factory or the shopping area (p〈0.01). 4) groups of students whose school was located near the park or the residential street had a higher degree of recognition that the environment around the school was harmful than groups of students whose school was located near the amusement area or the shopping area (p〈0.05). Fourthly, 1) relating to the harmful shops where they experienced most highly the behavior of drinking and smoking, middle school students responded that they did so in the electronic game room (22.5％) and high school students did so in the singing room (31.4％), and high school students had a very high experience ratio of drinking and smoking, compared with middle school students (p〈0.001). 2) relating to the harmful shops where they could get in contact with lewd articles, both of middle school students (5.3％) and high school students (8.3％) responded that they could do so in the video room. 3) relating to the harmful shops where they experienced unsound opposite sex acquaintance, both of middle school students (5.8％) and high school students (16.6％) responded that they did so most highly in hotels, and high school students had a remarkably high experience ratio of unsound opposite sex acquaintance, compared with middle school students (p〈0.05). 4) relating to the harmful shops where they experienced violence, middle school students responded that they did so in the electronic game room (14.0％) and then in the singing room (3.7％), and high school students responded that they did so in the electronic game room (9.3％), the nightclub (4.6％), Soju-room (4.1 ％), and high school students had a remarkably high experience ratio of violence, compared with middle school students (p〈0.05). 5) relating to the harmful places where they experienced drugs both of middle school students (0.8％) and high school students (2.4％) responded that they did so in the hotels. Fifthly, when going to the harmful shops, students had the experience of being guided and regulated roughly 1 time - 2 times, and middle school students (16.4％) and high school students (16.7％) had almost similar experience ratios of being guided and regulated. Conclusively, there was a limit in controlling the environment and purification zone only by legal regulations and institutional controls, the self-control purification effort for the school and the surrounding environment was required greatly, in order to protect students from harmful environment. In addition, the constant study to establish the educational environment purification measures must be carried out.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.10
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• pp.1378-1387
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• 2012

To investigate the pharmacological activity of chaga mushroom (Inonotus obliquus) on extraction conditions, chaga was extracted using water (reflux at $50^{\circ}C$, decoction over $90^{\circ}C$, pressure at $121^{\circ}C$) or ethanol (reflux at 50, 70, or $90^{\circ}C$). When water extract was further fractionated into crude polysaccharide (IO-CP), yields of IO-CP (4.8~16.8%) were higher than those of ethanolic extracts (IO-E, 1.9~2.7%) at increased temperature. For antioxidant activity, crude polysaccharide (IO-CP-121) obtained by pressurized extraction showed the highest polyphenolic and flavonoid contents (35.10 mg TAE/g and 18.48 mg QE/g, respectively) as well as DPPH and ABTS free radical scavenging activities (26.08 and 27.99 mg AEAC/100 mg, respectively). Meanwhile, IO-CP-D (decoction) and IO-CP-50 (reflux) had more potent mitogenic effects (2.10- and 1.95-fold of saline control at 100 ${\mu}g/mL$) as well as intestinal immune system modulating activities (6.30- and 5.74-fold) compared to IO-CP-121, whereas ethanolic extracts showed no activity. Although no IO-CP showed cytotoxicity against RAW 264.7 cells at 0.1 mg/mL, IO-CP-121 significantly inhibited TNF-${\alpha}$ and NO production as pro-inflammatory factors in LPS-stimulated RAW 264.7 cells (29.2 and 63.5%, respectively). Ethanolic extracts also showed no cytotoxicity at 0.1 mg/mL, whereas inhibition of TNF-${\alpha}$ and NO production was significantly low compared to that of IO-CP-121. In addition, active IO-CP-D was further fractionated into an unadsorbed (IO-CP-I) and seven adsorbed fractions (IO-CP-II~VIII) by DEAE-Sepharose CL-6B column chromatography in order to isolate immunostimulating polysaccharide. IO-CP-II showed the most potent mitogenic effect and macrophage stimulating activity (4.51- and 1.64-fold, respectively). IO-CP-II mainly contained neutral sugars (61.86%) in addition to a small amount of uronic acid (2.96%), and component sugar analysis showed that IO-CP-II consisted mainly of Glc, Gal, and Man (molar ratio of 1.00:0.55:0.31). Therefore, extraction conditions affect the physiological activity of chaga, and immunostimulating polysaccharide fractionated from chaga by decoction is composed mainly of neutral sugars.