• Journal of the Korean Crystal Growth and Crystal Technology
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• v.14 no.4
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• pp.135-139
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• 2004

The layered organic-inorganic hybrid compounds($C_6H_5CH_2NH_3)_2CuCl_4$ and ($NH_3C_6/H_4C_2H_4_6/H_4NH_3)CuCl_4$ have been directly synthesized. From the X-ray diffraction data and the organic guest size, the orientation of the intercalated organic amine was determined. The inorganic sheets consist of $CuCl_4^{2-}$layers of comer-sharing octahedra copper chloride. The protonated organic amine was intercalated into the $CuCl_4^{2-}$layers with bilayer structure for ($C_6H_5CH_2NH_3)_2CuCl_4$ and monolayer structure for ($NH_3C_6/H_4C_2H_4_6/H_4NH_3)CuCl_4$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.3
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• pp.257-264
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• 1986

The Chromosomes of five cobitid fishes, Cobitis taenia taenia, C. taenia lutheri, C. taenia striata, C. longicorpus and C. koreensis were studied. The karyotypic studies were based on the observations from the flame-drying preparations. The results obtained such as the number of somatic chromosomes, the type of chromosomes according to the centromeric loci and the number of chromosomal arm(AN) were as follows: C. longicorpus, 2n=50, 12m-8sm-30a, AN=70; C. koreensis, 2n=50, 10m-12sm-28a, AN=72; C. taenia taenia, 2n=48, 14m-4sm-30a, AN=66: C. taenia lutheri, 2n=50, 10m-6sm-34a, AN=66; and C. taenia striata, 2n=50, 10m-6sm-34a, AN=66. Peculiarly, in the case of C. taenia lutheri the chromosome number of somatic diploid was found to be 48-51, however, the number of chromosomal arm was 66, irrespective of the difference in the numbers of each somatic genome. It was confirmed there exists the Robertsonian event, one of the chromosomal polymorphism in C.t. lutheri. It was remarked taxonomically that the karyotype of C. taenia taenia of Korea having 48 diploid chromosomes was not identical with that of Europe and Japan with 50 chromosomes. Based on the karyotype analysis the Korean cobitid fishes can be classified roughly into three species groups according to arm numbers and diploid numbers; 1) C. taenia taenia, C. taenia lutheri, C. taenia striata 2) C. koreensis, C. longicor pus, C. rotundicaudata and 3) C. granoei.

• Korean Journal of Materials Research
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• v.7 no.11
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• pp.934-941
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• 1997

C $r_{3}$ $C_{2}$-20wt% NiCr 이 크래드된 분말을 이용하여 HVOF 용사층의 특성(미세조직, 결정상, 경도 그리고 erosion rate)에 미치는 연료/산소 비(=3.2,3.0,2.8,2.6)의 영향을 조사했다. 실험범위 내에서 F/O=3.0의 경우가 C $r_{3}$ $C_{2}$-20wt%(NiCr)크래드 분말의 최적용사조건 이었다. XRD분석결과 F/O비에 관계없이 카바이드분해는 일어 났다. C $r_{3}$ $C_{2}$에서C $r_{7}$ $C_{3}$로의 상변화는 F/O비가 감소함에 따라 증가했다. 열처리 온도가 높아짐에 따라 C $r_{7}$ $C_{3}$분율은 증가 하였으며, 100$0^{\circ}C$에서 50시간 열처리후 용사층의 주된상은 C $r_{7}$ $C_{3}$이였다. 용사상태에서 경도값은 F/O=3.0조건으로 용사된 코팅층이 $H_{v300}$-1040으로 가장 높았으며, 공기중에서 $600^{\circ}C$, 50시간 열처리한 후, 경도값은 1340으로 증가하였다. 그리고 80$0^{\circ}C$열처리 후 경도값은 약간 감소하였다. 그러나 100$0^{\circ}C$ 열처리 후에도 1060정도로 용사상태의 경우 보다는 높은 경도값을 유지하였다. 이와같이 경도값이 증가하는 이유는 열처리에 따라 용사층이 치밀하게 되고 또한 C $r_{2}$ $O_{3}$의 산화물이 C $r_{3}$ $C_{2}$/C $r_{7}$ $C_{3}$ 내에 생성되어 탄화물/산화물 복합체를 이루기 때문으로 생각된다. 용사상태에서 drosion rate는 F/O비에 따라 2.6-3.05x$10^{-4}$mg/g까지 변화하였다. 또한 $600^{\circ}C$열처리 후에는 2.15-2.3 x $10^{-4}$mg/g이였으며, 80$0^{\circ}C$에서 열처리한 후에는 2.3-2.4x$10^{-4}$mg/g으로 $600^{\circ}C$열처리후 보다 약간 높은 결과를 보였다.결과를 보였다.

• Clinical Pain
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• v.18 no.1
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• pp.8-15
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• 2019

Objective: To determine the relationship between cervical sagittal parameters and the degree of the cervical disc degeneration at each cervical level by using cervical plain radiographs and disc degeneration grading. Method: This study analyzed 110 patients with posterior neck pain. Cervical radiographic measurements included the occipito-cervical (O~C2) angle; sagittal Cobb angles of C1~C2, C2~C7; and sagittal vertical axis (SVA) of C1~C7 and C2~C7. The degenerations of cervical discs at each level were evaluated through Pfirrmann grading system by magnetic resonance images of the cervical spine. The correlations between the cervical sagittal measurements and the disc degeneration at each level were analyzed by Spearman's correlation. Results: A significant correlation was found for the C2~C7 angle with disc degenerations at C2~C6 levels. O~C2 angle was correlated significantly with disc degenerations at C2~C4 and C5~C7 levels. There was significant correlation between C1~C2 angle and disc degeneration at C6~C7 level. No significant relationship was found between the cervical SVA and the cervical disc degeneration at all cervical levels. Conclusion: Cervical sagittal parameters representing cervical angles (C2~C7, O~C2, and C1~C2 angles) were significantly correlated with the degree of the cervical disc degeneration. These findings suggest that the loss of the natural cervical lordosis rather than loss of natural SVA could be correlated with progression of the cervical disc degeneration.

• Journal of the Korean Ceramic Society
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• v.40 no.1
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• pp.87-92
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• 2003

$Ti_3AlC_2$was synthesized from TiCx and Al powder as a starting materials at the temperature range between$800^{circ}C;and;1500^{\circ}C$. The vacuum sintering and hot pressing methods were imployed to synthesize$Ti_3AlC_2$. The high purity$Ti_3AlC_2$was synthesized using TiCx and Al powder as starting materials without formation of Ti-Al intermetallic compound and Al-C compound.$Ti_2$AlC and$Ti_3AlC_2$were preferentially synthesized at$800^{\circ}C$and above$1200^{\circ}C$, respectively.$Ti_2$AlC formed at low temperature was transformed to$Ti_3AlC_2$by further reaction with TiC. In this study, the synthesis mechanism for$Ti_3AlC_2$was proposed. The synthesized$Ti_3AlC_2$showed the nano laminating structure consisting of$Ti_3AlC_2$crystal with the thickness of 45~120 nm.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.13
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• pp.5411-5416
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• 2014

Background: A number of studies have reported relationships of CYP2E1 RsaI/PstI polymorphisms with susceptibility to lung cancer in Chinese population. However, the epidemiologic results have been conflictive rather than conclusive. The purpose of this study was to address the associations of CYP2E1 RsaI/PstI polymorphisms with lung cancer risk in Chinese population comprehensively. Materials and Methods: Systematic searches were conducted in the PubMed, Science Direct, Elsevier, CNKI and Chinese Biomedical Literature Databases. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to estimate the strength of association. Results: Overall, we observed a decreased lung cancer risk among subjects carrying CYP2E1 RsaI/PstI c1/c2 and c1/c2+c2/c2 genotypes (OR=0.76, 95%CI: 0.64-0.90 and OR=0.78, 95%CI: 0.66-0.93, respectively), as compared with subjects carrying the c1/c1 genotype. In subgroup analysis, we observed a decreased lung cancer risk among c1/c2 carriers in hospital-based studies (OR=0.81, 95%CI: 0.68-0.98) and among carriers with c1/c2 and c1/c2+c2/c2 genotypes in population-based studies(OR=0.57, 95%CI: 0.42-0.79 and OR=0.58, 95%CI: 0.43-0.79, respectively), as compared with subjects carrying the c1/c1 genotype. Limiting the analysis to studies with controls in Hardy-Weinberg equilibrium (HWE), we similarly observed a decreased lung cancer risk among c1/c2 and c1/c2+c2/c2 carriers (OR=0.73, 95%CI: 0.60-0.88 and OR=0.73, 95%CI: 0.60-0.88, respectively), as compared with c1/c1. Conclusions: Our results suggested that CYP2E1 RsaI/PstI c1/c2 and c1/c2+c2/c2 variants might be a protective factor for developing lung cancer in Chinese population. Further well-designed studies with larger sample size are required to verify our findings.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1252_1253
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• 2009

The composites were fabricated by adding 0, 15, 20, 25[vol.%] Zirconium Diboride(hereafter, $ZrB_2$) powders as a second phase to Silicon Carbide(hereafter, SiC) matrix. The physical, mechanical and electrical properties of electroconductive SiC ceramic composites by spark plasma sintering(hereafter, SPS) were examined. Reactions between $\beta$-SiC and $ZrB_2$ were not observed in the XRD analysis The relative density of mono SiC, SiC+15[vol.%]$ZrB_2$, SiC+20[vol.%]$ZrB_2$ and SiC+25[vol.%]$ZrB_2$ composites are 90.97[%], 74.62[%], 77.99[%] and 72.61[%] respectively. The XRD phase analysis of the electroconductive SiC ceramic composites reveals high of SiC and $ZrB_2$ and low of ZrO2 phase. The electrical resistivity of mono SiC, SiC+15[vol.%]$ZrB_2$, SiC+20[vol.%]$ZrB_2$ and SiC+25[vol.%]$ZrB_2$ composites are $4.57{\times}10^{-1}$, $2.13{\times}10^{-1}$, $1.53{\times}10^{-1}$ and $6.37{\times}10^{-2}[{\Omega}{\cdot}cm]$ at room temperature, respectively. The electrical resistivity of mono SiC, SiC+15[vol.%]$ZrB_2$, SiC+20[vol.%]$ZrB_2$ and SiC+25[vol.%]$ZrB_2$ are Negative Temperature Coefficient Resistance(hereafter, NTCR) in temperature ranges from 25[$^{\circ}C$] to 100[$^{\circ}C$]. It is convinced that SiC+20[vol.%]$ZrB_2$ composite by SPS can be applied for heater above 1000[$^{\circ}C$].

• Korean Journal of Food Science and Technology
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• v.15 no.2
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• pp.108-111
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• 1983

High performance liquid chromatography (HPLC) was applied to the analysis of triglycerides of rice bran oil. The triglycerides were clearly separated in five peaks by HPLC on a column packed with ${\mu}-Bondapack$ C18 using methanol-chloroform mixture as a solvent. Compositions of the triglyceride and fatty acid of the fraction was also analyzed by gas liquid chromatography (GLC). Each of these collected fractions gave three to four peaks in the GLC chromatograms according to the carbon number of the triglyceride. The fitty acid compositions of these triglycerides were mainly composed of C16:0, C18:1 and C18:2 fatty acids. The major triglycerides of the rice bran oil were found to be those of (C16:0, C18:1, C18:2;16.64%), $(2{\times}C18:1,\;C18:2;16.18%)$, $(3{\times}C18:1;13.7%)$, $(C16:0,\;2{\times}C18:1;12.77%)$,$(C18:1,\;2{\times}C18:2;9.16%)$ and $(C16:0,\;2{\times}C18:2;6.42%)$

• The Korean Journal of Zoology
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• v.34 no.2
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• pp.228-231
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• 1991

The phenotyping of the sixth complement component (C6) was performed on plasma or serum samples from 383 unrelated Korean, by IEF and immunoblotting using anti-human C6 serum. Three common allotypes, C6 A, C6 B and C6 B2 and two rare allotypes, C6 Ml and C6 Mu were observed. The allele frequencies of C6*A, C6*B and C6*B2 were estimated to be 0.4399, 0.5144, 0.0392, respectively. These frequencies are similar to those of the Eastasian populations.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.1
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• pp.97-105
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• 1998

Antioxidation mechanism of Al metal powders on $Al_2O_3-C$ refractory was investigated in temperature range from 800 to $1400^{\circ}C$. The addition of 5 wt% Al metal powders suppressed the oxidation of carbon in $Al_2O_3$-C sample. The carbons were distributed uniformly on the surface and the interface of the $Al_2O_3$-C-Al. Reaction products of $Al_4C_3$ and AIN were found with a composition of Al-C at temperatures between 800 and $1200^{\circ}C$ and transformed to $Al_2O_3$ above $1400^{\circ}C$. Cavity structures related to the to the formation of $Al_4C_3$ were observed for the AI-C after heating at $1000^{\circ}C$ ofr 1 hour. Thermodynamic mechanism was considered to discuss the formation $Al_4C_3$, AlN and their transformation to $Al_2O_3$, which leads to the effect of oxidation resistance.