• Korean Journal of Veterinary Service
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• v.28 no.2
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• pp.99-106
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• 2005

This survey was carried out to investigate the seroprevalence of antibodies to Neospora caninum in Korean indigenous cattle that was representative livestock raised in Jeongeup province Jeonbuk Korea. A total of 1,162 sera were tested for N caninum antibodies using ELISA (Herdcheck anti-Neospora. IDEXX Laboratories Inc., Westbrook, Maine USA). $15(1.3\%)$ sera were positive by ELISA. A total of 290 farms were tested. $11(3.8\%)$ farms were positive. Among the seroprevalence of cattle according to the areas, 8 of 44 counties were infected N caninum. Sero-positive 11 farms of N caninum antibodies using ELISA test and 62 of 301 sera $(20.6\%)$ were infected to N caninum. We found that cattle be raised in Jeongeup province was slightly infected to N caninum. It seems to be infected of N caninum an early stage. but the positive rates was variable that it was $6\%\~62\%$. It was supposed to the highest positive rate of 3 farms had some factors to be infected. The factors were supposed to keep dogs yearly, located the base of hills, and almost feed with imported dried grass. Farmers suppose to the cause of abortion was not the neosporosis but also broke out an accident or was infected Brucella spp. The results of Brucella Rose Bengal Test (RBT) were all negative.

• Korean Journal of Materials Research
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• v.14 no.8
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• pp.558-564
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• 2004

In order to improve the low hardness and low wear resistance of Ti-6Al-4V alloy, plasma carburization treatment and CrN film coating were carried out. Effects of the plasma carburization and CrN coating were analyzed and compared with the non-treated alloy by mechanical and creep tests. After plasma carburization and CrN coating treatments, the carburized layer was about 150 ${\mu}m$ in depth and CrN coated layer was about 7.5 ${\mu}m$ in thickness. Hardness value of about $H_{v}$ 402 of the non-treated alloy was improved to $H_{v}$ 1600 and 1390 by plasma carburization and CrN thin film coating, respectively. Stress exponent(n) was decreased from 9.10 in CrN coating specimen to 8.95 in carburized specimen. However, the activation energy(Q) was increased from 242 to 250 kJ/mol. It can be concluded that the static creep deformation for Ti-6Al-4V alloy is controlled by the dislocation climb over the ranges of the experimental conditions.

• The Korean Journal of Applied Statistics
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• v.13 no.2
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• pp.343-352
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• 2000

In this study. the author proposes a nonhierarchical clustering method. called the "Double K-Means Clustering", which performs clustering of multivariate observations with the following algorithm: Step I: Carry out the ordinary K-means clmitering and obtain k temporary clusters with sizes $n_1$,... , $n_k$, centroids $c_$1,..., $c_k$ and pooled covariance matrix S. $\bullet$ Step II-I: Allocate the observation x, to the cluster F if it satisfies ..... where N is the total number of observations, for -i = 1, . ,N. $\bullet$ Step II-2: Update cluster sizes $n_1$,... , $n_k$, centroids $c_$1,..., $c_k$ and pooled covariance matrix S. $\bullet$ Step II-3: Repeat Steps II-I and II-2 until the change becomes negligible. The double K-means clustering is nearly "optimal" under the mixture of k multivariate normal distributions with the common covariance matrix. Also, it is nearly affine invariant, with the data-analytic implication that variable standardizations are not that required. The method is numerically demonstrated on Fisher's iris data.

• Honam Mathematical Journal
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• v.35 no.4
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• pp.707-716
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• 2013

The present paper consists of two parts. Since the recent paper [4] proved that an Alexandroff $T_0$-space is a semi-$T_{\frac{1}{2}}$-space, the first part studies semi-open and semi-closed structures of the Khalimsky nD space. The second one focuses on the study of a relation between the LS-property of ($SC^{n_1,l_1}_{k_1}{\times}SC^{n_2,l_2}_{k_2}$, k) relative to the simple closed $k_i$-curves $SC^{n_i,l_i}_{k_i}$, $i{\in}\{1,2\}$ and its normal k-adjacency. In addition, the present paper points out that the main theorems of Boxer and Karaca's paper [3] such as Theorems 4.4 and 4.7 of [3] cannot be new assertions. Indeed, instead they should be attributed to Theorems 4.3 and 4.5, and Example 4.6 of [10].

• Korean Journal of Materials Research
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• v.9 no.6
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• pp.599-603
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• 1999

We have investigated the growth characteristics of thick GaN on Sim substrate with AlN and low temperature GaN buffer layer. The vertical hydride vapor phase epitaxy system with $GaCl_3$ precursor was used for growth of GaN. AlN and GaN buffer layer were deposited on Si substrate to reduce the lattice mismatch and the thermal expansion coefficient mismatch between si and GaN. Optimization of deposition condition for AlN and low temperature GaN buffer layers were carried out. We studied the effects of growth temperature, V/III ratio on the properties of thick GaN. Surface morphology, growth rate and crystallinity of thick GaN were measured using Atomic Force Microscopy (AFM), $\alpha-step$-, Scanning Electron Microscopy (SEM) and X-Ray Diffractometer(XRD).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.14-14
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• 2006

Homoepitaxial growth of GaN on n-type GaN substrates was carried out by hydride vapor phase epitaxy (HVPE) method. This enables us to reduce or to eliminate the bowing of the GaN substrate caused by thermal mismatch. As a result, the two opposite crystal surfaces have been found to possess low dislocation density. The surface polarity of the homoepitaxially grown GaN was confirmed by both etching of the surface and conversion beam electron diffraction(CBED). The surface morphology and the photoluminescencemeasurement indicated that the surface properties of N-polar face of the homoepitaxlally grown GaN are quite different from the initial N-polar face of the heteroepitaxially grown GaN substrate Also, both surfaces of the GaN substrate were characterized by room temperature Double crystal X-ray diffraction (DCXRD) and photoluminescence measurement.

• Journal of Korean Physical Therapy Science
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• v.10 no.2
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• pp.193-198
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• 2003

Acupuncture has been used as a clinical treatment in Oriental medicine for various diseases. In the present study was carried out to investigate the effects of acupuncture and electrical stimulation on the change neuronal nitric oxide synthase(nNOS) immunoreactive cells in the periaqueductal gray(PAG) area of the male SD rats. Enhanced expression of nNOS was detected in the dorsolateral-PAG(DL-PAG) area of rat with stress by fixed body, and acupuncture and needle electrode electrical stimulation groups at Hapgok like acupoint decreased the stress-induced enhancement in the expression of nNOS. The present results demonstrate that acupuncture and needle electrode electrical stimulation is effective in the modulation of expression of nNOS in the DL-PAG area under stress conditions.

• Clinical and Experimental Reproductive Medicine
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• v.26 no.3
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• pp.467-474
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• 1999

Objectives: Cytogenetic investigations were carried out on 770 women with primary (n=560) and secondary amenorrhea (n=210) to determine the frequency of chromosomal or genetic causes of amenorrhea. Materials and Methods: In 770 women with primary amenorrhea (n=560) and secondary amenorrhea (n=210), chromosomal analysis were performed. Results: 1) The most prevalent age group is 16-20 years of age group with primary amenorrhea and 26-30 years of age group with secondary amenorrhea. 2) Out of 560 cases of primary amenorrhea, 343 cases (61.3%) had the normal chromosome constitution and 217 cases (38.7%) had the abnormal chromosome constitution including 46,XY. 3) In 217 cases of abnormal chromosome of primary amenorrhea, 57 cases (26.3%) had 45,X and 34 cases (15.8%) had the 46,XY, 24 cases (11.0%) had 45,X/46,X,i (Xq), 23 cases (10.6%) had 45,X/46,X,+mar and 14 cases (6.6%) had 45,X/46,XY. 4) Out of 210 cases of secondary amenorrhea, 181 cases (86.2%) had the normal chromosome constitution and 29 cases (13.8%) had the abnormal chromosome. 5) In 29 cases of abnormal chromosome of secondary amenorrhea, 7 cases (24.1%) had 45,X/46, X,i (Xq), 4 cases (13.8%) had 45,X/46,XX. Conclusion: High percentage of chromosomal abnormalities was diagnosed in primary amenorrhea and most of them were sex chromosome anomalies. In secondary amenorrhea, the prevalence was lower than primary amenorrhea, so a preselection of patients with secondary amenorrhea for cytogenetic investigations seems to be necessary.

• YAKHAK HOEJI
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• v.49 no.1
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• pp.56-59
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• 2005

We synthesized new N-substituted 3-amino-6-chloropyridazine derivatives which were expected to retain biological activity. All synthetic process from pyridazine to 3-aminopyridazines could be carried out conveniently in high yield. N-Substituted 3-amino-6-chloropyridazine derivatives were prepared through amination and acylation from 3,6-dichloropyridazine. 3-Amino-6-chloropyridazine was prepared from the reaction of 3,6-dichloropyridazine with liquid ammonia under autoclave for 6 hrs. The refluxing of 3-amino-6-chloropyridazine and the corresponding acid anhydride for $1{\sim}2$ hrs afforded the N-substituted 3-amino-6-chloropyridazines. Alkyl chain of N-substituent was prolonged to six carbon (hexanoic acid).

• The Journal of Korean Society of Virology
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• v.27 no.2
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• pp.257-260
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• 1997

Adenoviruses are icosahedral virions containing double-stranded linea DNA. They are 70 nm to 90 nm in diameter and capsid is composed of 252 capsomeres. Several members of this group, including types commonly associated with respiratory disease in man, are capable of producing malignant tumors in young hamsters and a few types have been shown to be oncogenic in young rat. Previous report involving effect of caffein on transformation induced by Adenovirus type 12 [9] has been carried out. The present report represents a continuation of previous study. To obtain evidence concerning the effect of MNNG (N-methyl-N'-nitro-N-nitroguanidine) on transformation, investigation of adenovirus type 12 of this group was undertaken. For practical consideration it was desirable to investigate the effect of MNNG on the adenovirus type 12 induced transformation in L cell. Results were as following 1. Adeno virus type 12 induced transformation was enhanced in the presence of MNNG. 2. Yields of adeno type 12 virus in L cell were slightly inhibited by treatment of MNNG.