• Nuclear Engineering and Technology
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• v.53 no.10
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• pp.3217-3228
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• 2021

Flow blockage of the fuel assembly in the lead-based fast reactor (LFR) may produce critical local spots, which will result in cladding failure and threaten reactor safety. In this study, the flow blockage characteristics were analyzed with the sub-channel analysis method, and the circumferentially-varied method was employed for considering the non-uniform distribution of circumferential temperature. The developed sub-channel analysis code SACOS-PB was validated by a heat transfer experiment in a blocked 19-rod bundle cooled by lead-bismuth eutectic. The deviations between the predicted coolant temperature and experimental values are within ±5%, including small and large flow blockage scenarios. And the temperature distributions of the fuel rod could be better simulated by the circumferentially-varied method for the small blockage scenario. Based on the validated code, the analysis of blockage characteristics was conducted. It could be seen from the temperature and flow distributions that a large blockage accident is more destructive compared with a small one. The sensitivity analysis shows that the closer the blockage location is to the exit, the more dangerous the accident is. Similarly, a larger blockage length will lead to a more serious case. And a higher exit temperature will be generated resulting from a higher peak coolant temperature of the blocked region. This work could provide a reference for the future design and development of the LFR.

• Journal of Food Hygiene and Safety
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• v.29 no.4
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• pp.322-326
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• 2014

According to Centers for Disease Control and Prevention (CDC, USA) recently it was reported that the children (< 5 year-old children) were more susceptible to Foodborne-illness. Confectionery products should be strictly controlled because they are children-preferred foods. Ministry of Food and Drug Safety (MFDS, South of Korea) tried to monitor contamination of organisms in confectionery products (such as biscuits, candies, chewing gums and ice candies) distributed in South Korea. MFDS evaluated the levels of indicator organisms: total aerobic bacteria, coliforms, Escherichia coli as well as the levels of food-borne illness organisms: Staphylococcus aureus, Bacillus cereus, Clostridium perfringens. Experimental plans for microbiological test were in accordance with the International Commission on Microbiological Specifications for Food (ICMSF). For this study, 1,005 samples were collected and from Seoul and Gyeongin region, South Korea. The average level of total aerobic bacteria in 1,005 samples was 1.7 log Colony Forming Unit(CFU)/g and the detection rate was 26.8%. The average level of Bacillus cereus was detected in 1.7 log CFU/g and the rate was 0.9%. There was no detection of coliforms, Escherichia coli, Staphylococcus aureus and Clostridium perfringens. The results of this study will be provided as the basic data to set the reasonable microbiological criteria of Korea Food Code.

• Journal of Food Hygiene and Safety
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• v.23 no.2
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• pp.108-112
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• 2008

A survey of total aflatoxin levels was conducted on 158 samples (nuts, fermented foods and their processed products) collected in local markets in Gyeonggi-do and Domestic Internet Site. The total aflatoxins were quantified by the immunoaffinity column clean-up method followed by high performance liquid chromatography (HPLC)-fluorescence detector (FLD). Aflatoxins were found in 45(28.5%) samples including 34 nuts and nut products, 7 soybean pastes, 1 meju, 1 bean product and 2 corn snacks with a range of $0.02{\sim}3.96\;{\mu}g/kg$. These results show that the contamination level of aflatoxin in foods consumed in Korea is low compared with the standard in Korea Food Code($10\;{\mu}g/kg$ as aflatoxin $B_1$). Aflatoxin $B_1$ content was increased in peanuts and com snacks during storage but it was decreased in doenjang (soybean paste).

• KSBB Journal
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• v.8 no.5
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• pp.431-437
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• 1993

Active carbon which has the smallest bulk and wet density was found as the best support media among 4 different kinds of materials(celite, natural zeolite, Pusuk stone, active carbon) to make a proper fluidized-bed with small energy consumption. Its minimum and optimum fluidization velocity were found as 0.03cm/sec and 0.25cm/sec, respectively. As organic loading rate for methane fermentation was increased, CODcr removal efficiencies of all the media were decreased. But, CODcr, removal efficiencies of active carbon was maintained more than 90% in this experimental range of the organic loading rate. Larger amount of microorganism was adsorbed on the active carbon which has very high specific surface area. At the organic loading rate of 16g CODcr,/l day, its adsorbed cell mass was 157mg/g. Comparing natural zeolite with roast celite, adsorbed cell mass did not increase in proportion to specific surface area of the media. Even though roast celite has the same specific surface area as the Pusuk stone, its organic removal ability was superior to that of the Pusuk stone, which explains that the relatively great surface roughness and the positive surface charge are important for cell adsorption. It was concluded that the support media for anaerobic fluidized reactor should have small wet density and small fuidization velocity, if possible, in order to increase cell adsorption by reducing the fluid shear stress.

• Journal of Food Hygiene and Safety
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• v.12 no.1
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• pp.26-38
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• 1997

The quality changes of hams and sausages in refrigerated storage were investigated. Seven types of hams and six types of sausages produced in Korea were collected from markets and stored at 1$0^{\circ}C$ according to the Food Code of Korea, and then chemical, microbiological, textural and sensory characteristics were evaluated at 30, 40 and 50 days. The proximal analysis showed considerable variation in fat with less variation in moisture and protein. The pH values of hams and sausages slightly changed with no consistent difference. Water activity values of all samples except one type of sausage were consistent over time in refrigerated storage. No purge losses of hams were observed except two types of samples in the intial stage. Several types of sausages showed purge losses with no consistency and one type of sausage showed consistent purge losses (0.44~11.29%) during the storage. The volatile basic nitrogen (VBN) content of hams and sausages was still within 20 mg% (Standard and Specification of Korea) on the 50th day, although the VBN of all samples significantly increased over time (p<0.05). The thiobarbituric acid (TBA) values of hams and sausages were well below 1.0 during the storage, although the TBA values of all samples significantly increased (p<0.05). However it was noticed that one type of ham and two types of sausages showed TBA values of 0.945, 0.928 and 0.978, respectively. All the standard plate counts (SPCs) of hams during the storage period showed a level below 30 CFU/g except one type of sample with 103 CFU/g at 50 days. All the SPCs of sausages showed a level below 50 CFU/g except one type of sample with 102 CFU/g and two types of samples with 104 CFU/g on the 50th day. Coliform groups were not counted in all samples during the storage. Instrumental texture analysis showed that springiness, cohesiveness, chewiness, gumminess and adhesiveness slightly changed with no consistent difference. The hardness of the hams showed a decreasing tendency, and the hardness of the sausages an increasing tendency with no significant difference. Sensory evaluation for color, flavor, taste, texture and overall acceptability showed decreasing tendencies over time (p<0.05). The scores of the five sensory characteristics maintained the medium level of quality at the termination of the experiment. Although the results indicated that the ham and sausage samples were acceptable after the 50 days' storage at 1$0^{\circ}C$, the shelf-life of the samples should be determined considering the rapid growth of bacteria and the high TBA values at 50 days.

• Journal of Food Hygiene and Safety
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• v.24 no.2
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• pp.169-173
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• 2009

A survey of total aflatoxin levels was conducted on 145 samples(carthamiflos, thujae semen, giycyrrhizae radix et rhizoma) collected in Yakyeang markets in Seoul. Aflatoxin levels were quantified by the immunoaffinity column clean-up method followed by performance liguid chromatography(HPLC)-fluorescence detector(FLD). Aflatoxins were found in 10(6.9%)samples including 5 Arecae semen, 4 Thujae semen, 1 Zizyphi semen with a range of $0.45{\sim}79.15\;{\mu}g/kg$. Generally These results show that the contamination level of aflatoxins in Herb Medicines consumed in Korea is high compared with the standard in Korea Herb Medicine Code($10\;{\mu}g/kg$ as aflatoxin B1). It is considered that aflatoxin concentration was increased in herb medicines during a storage and drying in herb medicines examined

• Journal of radiological science and technology
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• v.40 no.4
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• pp.605-611
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• 2017

The structure of the actual detector was computed using the code of the PENELOPE. Using the standard mixed sources (450, 1,000 ml), compare the effectiveness of each energy according to various densities and height of the PENELOPE computer simulation, and calculate the effectiveness of the various environmental specimens and apply them to various environmental specimens to determine the lower limit. The values obtained by the obtained value were obtained by applying the obtained efficiency to the actual environmental specimens and obtaining the lower limit values. The density correction factor is 1.155 g of the density correction factor of $0.4g/cm^3$ (59.54keV), 1.153 (661 keV), $1.06g/cm^3$ 1.064 (1,836.04keV), 1.03, and 1.033. It was confirmed that the radioactivity concentration of environmental samples decreased as the amount of specimen was measured increases, and the MDA value decreased as time measured increases.

• Journal of Korean Philosophical Society
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• v.117
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• pp.355-372
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• 2011

G. Deleuze a $exerc{\acute{e}}$ sa philosophie $cin{\acute{e}}mathographique$ dans ses œuvres essentielles $Cin{\acute{e}}ma$ 1: l'Image-Mouvement(Minuit:1983) et $Cin{\acute{e}}ma$ 2: l'Image-Temps(Minuit:1985) qui n'indiquent pas l'histoire $cin{\acute{e}}mathographique$ mais la taxinomie, et par $cons{\acute{e}}quent$, de l'image et du code. Cette ${\acute{e}}tude$ consiste donc $\grave{a}$ rendre compte la de l'image que G. Deleuze touche dans cette $d{\acute{e}}finition$ et $\grave{a}$ $v{\acute{e}}rifier$ quelles images peuvent ${\hat{e}}tre$ $cat{\acute{e}}goris{\acute{e}}es$: comment. Nous distinguons l'image-mouvement et l'image-temps qui sont les $cat{\acute{e}}gories$ essentielles chez $Cin{\acute{e}}ma$. C'est surtout sur ce point que nous insistons. Dans ce cas, nous discutons aussi de la question des spectateurs du film qui conduit. Cette question permet susciter de la $mani{\grave{e}}re$ $d^{\prime}{\hat{e}}tre$ des spectateurs entre le film qui est $compos{\acute{e}}$ de l'image-mouvement dont G. Deleuze decrit comme 'classique' et le film qui est $trait{\acute{e}}$ de l'lmage-temps dont il $d{\acute{e}}finit$ comme 'moderne': quelle variation. Dans ce point $d^{\prime}{\acute{e}}tude$, G. Deuleuze ecrit cette question $mentionn{\acute{e}}e$ $\grave{a}$ travers son oeuvre $Cin{\acute{e}}ma$($\grave{a}$ voir ch.7, Volume2).

• Journal of Korean Society of Steel Construction
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• v.17 no.3 s.76
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• pp.347-356
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• 2005

Recently, pre-engineering building (P.E.B.) systematic frames are increasingly being used in steel factory buildings, but almost of the related techniques are dependent on the engineering program (e.g, MBS, LTI), which is usually imported from other countries. These are designed under the AISC-ASD because at present there is no Korean design code for P.E.B. frames. Also, there are few studies onbehaviour and we need to develop the element techniques by using H-shaped components.In particular, there is a tendency towards overestimated design because column-rafter connections have been designed with extended end plate type joint, which is treated asrigid joint,so structural examinations are needed. Therefore, this study represents a basic step in ascertaining the application of P.E.B. systematic frames by using H-shaped column-rafter connectionwith flush type end plate. Its structural performance is compared with that of existing extended type joint using a structural performance test. The structural behaviour of specimen was understood qualitatively and the possibility of application (e.g, design aid charts) of semi-connection (flush type) with H-shaped column-rafter was determined.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.4
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• pp.41-46
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• 2016

Recently, many domestic and foreign corporates are concentrating in investment to wearable devices and users are provided with various service based on wearable devices 26% more than compared to last year. It is widely used in previous healthcare, smart work, smart home environment, and it is now introduced to get connection to fused service environment. However, as products of G company are commercialized, the security issue of personal information is causing dispute in society, and the danger of data management and security regarding telecommunication is increasing. Also, because the password system used in previous wireless environment is still in use, there are possible vulnerability considering the new and mutant security threat. This thesis conducted study about protocols that can exercise safe telecommunication in the basis of wearable devices. In the registration and certification process, the signature value is created based on the code value. The telecommunication method is designed to conduct safe telecommunication based on the signature value. As for the attack method occurring in the wearable device environment, the safety was analyzed and conducted performance evaluation of previous password system and proposal system, and verified about 14% of efficiency.