• Journal of Magnetics
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• v.5 no.1
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• pp.16-18
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• 2000

The garnets $Nd_{1-x}Bi_xY_2Fe_5O_{12}$ ($\chi$=0.0, 0.25, 0.5, 0.75 and 1.0) have been studied by x-rays, electron microscopy, ferromagnetic resonance, vibrating sample magnetometer and Mossbauer spectroscopy, Ultra-fine polycrystalline cubic samples have been prepared by a melt-salt routed sol-gel method. The Mossbauer spectra consist of two sets of six-line patterns corresponding to $Fe^{3+}$ at the tetrahedral 24(d) and octahedral 16(a) sites. Magnetic hyperfine fields of $Nd_{0.5}Bi_{0.5}Y_2Fe_5O_{12}$ at 12 K are found to be 548 kOe (octahedral site) and 475 kOe (tetrahedral site), respectively, It is found that Debye temperatures for the tetrahedral and octahedral sites of $Nd_{0.75}Bi_{0.25}Y_2Fe_5O_{12}$ are $\theta_{tet}=436$ K and $\theta_{oct}=285$ K, respectively, The iron ions at both sites are highly covalent ferric. The Nel temperature decreases linearly with Bi concentration, from 630 K fur $\chi$=0.0 to 600 K for $\chi$=1.0, suggesting that the superexchange interaction for the Nd-O-Fe link is stronger than that for the Bi-O-Fe link. As a consequence, the coercivity of $Nd_{1-x}Bi_xY_2Fe_5O_{12}$ drastically decreases and the magnetization remains almost constant as x increases.

• Journal of Magnetics
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• v.16 no.3
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• pp.229-233
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• 2011

Phase evolution during the hydrogen-assisted disproportionation of $Nd_{12.5}Fe_{80.6}B_{6.4}Ga_{0.3}Nb_{0.2}$ alloy was investigated mainly by using a magnetic balance-type thermomagnetic analyser (TMA). In order to avoid any undesirable phase change in the course of heating for TMA, a swift TMA technique with very high heating rate (around 2 min to reach $800^{\circ}C$ from room temperature) was adopted. The hydrided $Nd_{12.5}Fe_{80.6}B_{6.4}Ga_{0.3}Nb_{0.2}$ alloy started to be disproportionated in hydrogen from around $600^{\circ}C$, and the alloy after the early disproportionation (from 600 to $660^{\circ}C$) has been partially disproportionated. The partially disproportionated alloy consisted of a mixture of $NdH_x$, $Fe_3B$, ${\alpha}$-Fe, and the remaining undisproportionated $Nd_2Fe_{14}BH_x$-phase. During the subsequent heating to $800^{\circ}C$ in hydrogen, two additional phases of $Fe_{23}B_6$ and $Fe_2B$ were formed, and the material consisted of a mixture of $NdH_x$, $Fe_{23}B_6$, $Fe_3B$, $Fe_2B$, and ${\alpha}$-Fe phases. During the subsequent isothermal holding at $800^{\circ}C$ for 1 hour, the phase constitution was further changed, and one additional unknown magnetic phase was formed. Eventually, the fully disproportionated $Nd_{12.5}Fe_{80.6}B_{6.4}Ga_{0.3}Nb_{0.2}$ alloy consisted of $NdH_x$, $Fe_{23}B_6$, $Fe_3B$, $Fe_2B$, ${\alpha}$-Fe, and one additional unknown magnetic phase.

• Journal of the Korean Magnetics Society
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• v.2 no.3
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• pp.233-238
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• 1992

Melt-spun $Nd_{14}Fe_{76}Co_4B_6$ and $Nd_{10.5}Fe_{79}Co_2Zr_{1.5}B_7$ ribbons were prepared under an externally applied magnetic field. Magnetic properties in terms of anisotropy were evaluated by discussing the effect of textured structure of the ribbon samples as well as its powders. About 32 % increase in $(B{\cdot}H)_{max}$ and 18.8 % increase in $B_r$ were observed along the perpendicular direction of the ribbon plane which is more prominent for the Nd-Fe-Co-Zr-B than for the Nd-Fe-Co-B alloy. The enhancement of magnetic anisotropy was monitored by measuring the anisotropy constant of each alloy as a function of quenching rate of the ribbon. It was found that for the melt-spun ribbon quenched at slow rate(less than 7 m/s) the magnetic field effect was overwhelmed by the heat gradient effect through the ribbon thickness while the field effect was prominent at intermediate quenching rate (more than 7~11 m/s). The reproducible maximum energy product, $(B{\cdot}H)_{max}$=16.4 MGOe can be obtained from the Nd-Fe-Co-Zr-B alloy.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.31 no.5
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• pp.401-407
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• 2009

Purpose : This study was designed to evaluate the clinical aspect of cysts which arised in the oral and maxillofacial region. Patients and Methods : We reviewed clinical record, radiograph, histopathologic and operative report of 155 patients who had been diagnosed as cysts and treated at the department of oral and maxillofacial surgery in Chonnam National University Hospital from January 2003 to December 2008. Gender, age, classifiaction, anatomic distribution, clinical sign and symptoms, treatment, complications and recurrence rate were studied. Results : 1. Among 155 patients, the male patients(64.5%) were more than the female(35.5%). 2. The average age ofthe patients was 37.2 years(ranging from 5 to 79 years). 3. In pathologic classification, radicular cyst and dentigerous cyst were most common cysts, irrespective of 73 cases(48.3%) and 35 cases(23.2%). 4. The frequently involved cystic regions were followed as mandibular molars(38.1%), and maxillary incisors(30.2%). 5. The frequent sequence of clinical symptoms was edema(29.9%), no symptom(18.9%), tenderness(13.9%), pain(11.5%) and abscess(9.4%). 6. The most prevalent treatment was the combination operation, such as cyst enucleation with extraction or endodontic treatment of the causative tooth(76.8%) 7. Among 155 cases, 2 cases that were treated using enucleation method were recurred(1.3%).

• The Journal of Korean Academy of Prosthodontics
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• v.37 no.2
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• pp.242-255
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• 1999

The purpose of this study was to estimate the morphology and the size of permanent mandibular molar in Korean Adult. The 100 dental college students with a normal dentition and without any dental prosthesis and severe caries were selected for this study The subjects were taken impression to make study model. On the study model, the 5 dentists measured those sizes and estimated morphological structures with a calipers, a Boley gauge and a protractor. The results were as follows; 1. The clinical crown height, width, thickness and the other anatomical structures had symmetrical relationship between the left and right mandibular molar. 2. In the clinical crown height aspect, the buccal crown heights always were higher than the lingual crown height. The heights of the each surface, the buccal or lingual surface, were gradually decreased from the 1st molar to the 2nd molar and the difference on the buccal surface was higher than that on the lingual surface. 3. In the clinical crown width aspect, the mesiodistal measurement of the mandibular 1st molar was higher than that of the mandibular 2st molar. 4. In the clinical crown thickness aspect, the mesial buccolingual measurement was highest on the mandibular 1st molar and the distal buccolingual distance was lowest on the mandibular 2nd molar. This distal thickness of the mandibular molar always was higher than that of the mesial half. 5. The well-developed mesiobuccal groove of the 1st molar was observed more often than that of the 2nd molar. The buccal pit was also observed more frequently at the 1st molar, but the frequency(35%) was not high. 6. The occlusal type according to the number of cusp was almost 5-cusp(98%) in the 1st molar and was also 5-cusp(63%) in the 2nd molar. The frequency of the 6th cusp was 31% in the 1st molar and was 22% in the 2nd molar. The frequency of the 7th cusp was below 2of in the both teeth. 7. In the buccolingual intercuspal distance aspect of the mesial and distal half, the intercuspal distance of distal half was higher than that of the mesial half on the 1st and 2nd molar, but the difference on the 1st molar was higher than that on the 2nd molar. 8. The difference between the widths of the buccal and lingual half was 1.5mm in the 1st molar and 0.8mm in the 2nd molar. Therefore the lingual convergency of the occlusal surface was more higher in the 1st molar. 9. On the mandibular 1st and 2nd molar, the distobuccal external angle was more acute than the mesiobuccal external angle. But the mesiobuccal internal angle was more acute than the distobuccal internal angle. 10. When the mandibular molar was a 5-cusp type, the development of the distal cusp on the 1st molar was better than that on the 2nd molar. The difference between the cusps was around 0.4mm.

• Journal of Preventive Medicine and Public Health
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• v.23 no.1 s.29
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• pp.57-64
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• 1990

Since the reservoir of leptospires organism is consisted of a broad spectrum of animals, the best method of prevention is vaccination. The clinical trial of leptospires vaccine conducted on human volunteer for its immunogenicity and safety. Summarized results are as following : 1. The Oral temperature among vaccinated group ranged from $36.7{\pm}0.46^{\circ}C\;to\;37.0{\pm}0.34^{\circ}C$, while in placebo injected group it ranged from $36.4{\pm}0.46^{\circ}C\;to\;36.7{\pm}0.53^{\circ}C$. There was no association between vaccination and fever (p>0.05) 2. Mild local reactions revealed in vaccinees were swelling (50-75% ), Redness($75{\sim}90%$), and induration ($25{\sim}40%$). Placebo injected group revealed only redness in 12.5% in 1st injection and 37.5% in second injection. The duration local reactions on injection site for th vaccinees and place groups disappeared within 48 hours. 3. Generalized Symptoms complained by the vaccinees were myalgia (25%), back pain(15%), headache (15%), pruritus(15%), and abdominal pain(10%), whereas placebo group complained of headache (25%), myalgia(12.5%), back pain(12.5%), pain in eyes(12.5%), abdominal pain(12.5%) pruritus (12.5%) and nausea(12.5%). 4. The serological test(MAT) of vaccinees showed geometric mean antibody titer as follows : a. L. icterohemorrhagiae lai 1 week after 1st vaccination : 22.45 1 week after 2nd vaccination : 111.23 3 week after 2nd vaccination : 266.64 b. L. canicola canicola 1 week after 1st vaccination : 24.62 1 week after 2nd vaccination : 123.92 3 week after 2nd vaccination : 276.55 c. L. icterohemorrhagiae copenhageni 1 week after 1st vaccination : 28.28 1 week after 2nd vaccination : 128.55 3 week after 2nd vaccination : 247.88 Whereas all of the place injected group showed below 1:20 titers. The sero-conversion rate of vaccinees were 100 percent.

• The Korean Journal of Pesticide Science
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• v.16 no.1
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• pp.54-61
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• 2012

The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), is one of the most important pest species devastating many horticultural and ornamental crops and fruit trees. Difficulty in managing this mite is largely attributed to its ability to develop resistance to many important acaricides. Development of 3,700-folds resistance to etoxazole was found in the population of T. urticae collected from rose greenhouses in Buyeo, Chungnam Province in August 2000. This population has been selected for eleven years with etoxazole (over 500 times), and increased over 5,000,000-folds in resistance as compared with susceptible strain. Also, etoxazole-resistant strain was shown to be maternally inherited. The objective of this study was to determine whether resistance of T. urticae to etoxazole was linked with point mutations in the mitochondrial gene. DNA sequencing of cytochrome c oxidase subunit I (COX1), COX2, COX3, cytochrome b (CYTB), NADH dehydrogenase subunit 1 (ND1), ND2, ND3, ND4, ND5, and ND6 were analyzed by comparing two etoxazole-susceptible and etoxazole-resistant strains. As a result, differences were not detected between the nucleotide sequences of two strains within a mitochondrial gene.

• Analytical Science and Technology
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• v.27 no.5
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• pp.254-260
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• 2014

In this study, heavy metals, PCDD/PCDFs, PAHs in wastes generated from thermal processes were analyzed. Waste from lead thermal metalurgy (EWC 10 04) inorganic metal substances in the regulation were detected in the highest concentrations of Pb. EWC 10 04 seems to be a result of the dust. Waste from zinc thermal metalurgy (EWC 10 05) inorganic metal substances in the regulation were detected in high concentration of Zn. EWC 10 05 seems to be a result of the dust. Waste from copper thermal metalurgy (EWC 10 06) Cu in the 651,77 mg/kg to 651 times higher than regulation standard appeared in the copper thermal metallurgy process seems to be a result of dust. The concentrations of PCDD/PCDFs ranged from 0.0005~11.748 ng-TEQ/g in dust, 0.0027 ng-TEQ/g in fly ash. PCDD/PCDFs content was not detected in excessive value in regulation standard. PAHs concentration was in the range of ND~118.9 mg/kg in Naphthalene, ND~9.6 mg/kg in Phenanthrene, ND~48.4 mg/kg in Benzo[b]fluoranthene, ND~62.6 mg/kg in Benzo[a]pyrene, ND~10.7 mg/kg in Fluoranthene, ND~11.5 mg/kg in Benzo[a]anthracene.

• Journal of Food Hygiene and Safety
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• v.18 no.1
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• pp.30-32
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• 2003

This study was performed to investigate the contents of nitrites in 450 meat products in Seoul from Jan. to Dec. in 2002. Sorbic acid contents of the samples were determined by Gas Chromatography. 67 samples of 450 (14.9%) were detected in sorbic acid contents. In each meat products, 65,6% (21/32) in dried meats, 17.6% (3/17) in bacon, 11.7% (27/231) in hams, 11.7% (13/111) in sausages, and 11.5% (3/26) in meat cu. The concentration range of Sorbic acid and its average content in each of the meat products are as follows: ND-1.21 g/ Kg and 0.34 g/kg in dried meat, ND-0.84 g/Kg and 0.12 g/Kg in bacon, ND-1.27 g/Kg and 0.074 g/Kg in ham, ND- 0.90 g/Kg and 0.077 g/Kg in sausage, and ND-0.20 g/Kg, 0.015 g/Kg in can meat. Together, these results demonstrated that the processed market meat products must be reinforced to supply for the citizens as safe foods.

• Resources Recycling
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• v.20 no.5
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• pp.46-51
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• 2011

An extraction study of neodymium (Nd) was investigated with different individual and mixer of extractants such as PC88A, D2EHPA, Cyanex 272, Versatic acid 10 and D2EHPA+Alamine-304-1, D2EHPA+Alamine-308, D2EHPA+TBP, D2EHPA+TOPO, PC88A+Alamine-336 and PC88A+TBP respectively. In all cases, it was observed that the extraction percentage of Nd increased with increasing equilibrium pH and extractant concentration but rather opposite observation was found that the extraction percentage of Nd decreased with increasing TBP concentration along with D2EHPA. Adding TBP to PC88A had no favorable effect on the extraction of Nd, whereas use of a mixture of PC88A with Alamine336, increased the extraction percentage of Nd under the same condition. Based on our experimental studies, this paper reports the results on the basic approach and extraction of neodymium.