• Weed & Turfgrass Science
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• v.2 no.1
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• pp.88-94
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• 2013

Brown patch caused by Rhizoctonia solani AG-1 IB occurred on Kentucky bluegrass during late May through early October 2010 at golf course in Gyeongbuk Province, Korea. Disease symptoms on the turfgrass for spring season were leaf blights dying from the leaf tip, which appeared patches of brown color in the field. However, it appeared patches of dark brown color or gray brown color in fall. The fungus (B-7 isolate) of brown patch was isolated from the diseased leaf tissue and cultured on potato-dextrose agar (PDA) for identification. The young hyphae had acute angular branching and few septa and mature hyphal branches showed about 90-degree angles and development of monilioid cells, which were morphologically identical to Rhizoctonia solani AG-1 IB reported previously. DNA sequences of ribosomal RNA gene (internal transcribed spacer) of the fungus were homologous with similarity of 99% to those of Rhizoctonia solani AG-1 IB isolates in GenBank database, confirming the identity of the causal agent of the disease. Pathogenicity of the fungus was also confirmed on the creeping bentgrass and Kentucky bluegrass by Koch's postulates. This is the first report of brown patch on Kentucky bluegrass caused by Rhizoctonia solani AG-1 IB in Korea.

• Journal of the Korean Chemical Society
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• v.47 no.2
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• pp.121-126
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• 2003

Tris(2-cyclohexylaminoethyl)amine (L) was synthesized by the Schiff base condensation reaction of tris(2-aminoethyl)amine with cyclohexanone, followed by reduction. The thermodynamic characteristics, mole ratio and formation constant of [Zn(II)-L] complex were measured by the cyclic voltammetry and isothermal titration. In the case of Zn(II), well-defined cathodic and anodic peak were obtained at -1.02V and -0.48V vs Ag/AgCl , respectively. For the [Zn(II)-L] complex, both peaks were obtained at -1.19V and -0.45V vs Ag/AgCl, respectively. In addition, the peak height gradually increases as the scan rate increases, suggesting that the currents obtained were diffusion - controlled. The mole ratio and stability constant of the complex measured cyclic voltammerty were 1:1 and logK$_f$= 5.8, respectively. And the mole ratio and stability constant of the complexe calculated by isothermal titration method was 1:1 and logK =5.4, respectively. ${\Delta}$H, ${\Delta}$G and T${\Delta}$S for the complex formation were -53.0 kJ/mol, -31.1 kJ/mol, and -21.9 J/K at 25 ${\circ}$C, respectively.

• Journal of the Korean Vacuum Society
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• v.16 no.5
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• pp.311-321
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• 2007

We have researched the chemical defects of NiO ultrathin films grown on Ag(001) by x-ray photoelectron spectroscopy. In particular, O 1s and Ni 2p spectra were analyzed consistently with control film thickness, $O_2\;and\;H_2O$ partial pressure and substrate temperature. As a result, we could identify each chemical defect. In addition, we suggest the optimum growth condition to minimize the defect density.

• Journal of Preventive Medicine and Public Health
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• v.48 no.2
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• pp.74-83
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• 2015

Objectives: To examine the sex-specific factors associated with being unaware of one's hepatitis B virus surface antigen (HBsAg) seropositivity status in a large, HBsAg-positive population of Koreans. Methods: In total, 1197 subjects aged 19 years or older who were HBsAg-positive according to data from the 2007-2012 Korea National Health and Nutrition Examination Survey were included. Subjects were considered unaware of their HBsAg seropositivity status if they answered that they had no knowledge of being previously infected by the hepatitis B virus (HBV) or diagnosed with HBV hepatitis. Multivariate Poisson regression models with robust variance estimate were used to assess the significance of the variables using weighted frequencies. Results: The majority (77.8%) of HbsAg-positive Korean adults (females, 81.9%; males, 74.6%) were unaware of their HBsAg seropositivity status. We found that sex (female: prevalence ratio [PR] 1.19), household income (low: PR, 1.15), marital status (never married: PR, 1.18), self-rated health (moderate: PR, 1.14; good: PR, 1.12), and alcohol use (at least 2-3 times/wk: PR, 1.21) were associated with being unaware. In females, age (50 to 59 years: PR, 1.29; ${\geq}70$ years: PR, 1.30), household income (low: PR, 1.37; middle-low: PR, 1.24), and marital status (never married: PR, 1.33) were associated with being unaware. In males, self-rated health (moderate: PR, 1.14; good: PR, 1.21) and alcohol use (at least 2-3 times/wk: PR, 1.21) were associated with being unaware. Conclusions: Factors related to the socioeconomic status of females and the health-related behaviors of males were found to be associated with being unaware of one's HBsAg seropositivity status.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.9
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• pp.835-843
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• 2008

We have fabricated the source-drain electrodes for OTFTs by screen printing method and manufactured Ag pastes as conductive paste. To obtain excellent conductivity and screen-printability of Ag pastes, the dispersion characteristics of Ag pastes prepared from two types of acryl resins with different molecular structures and Ag powder treated with caprylic acid, triethanol amine and dodecane thiol as surfactant respectively were investigated. The Ag pastes containing Ag powder treated with dodecane thiol having thiol as anchor group or AA4123 with carboxyl group(COOH) of hydrophilic group as binder resin exhibited excellent dispersity. But, Ag pastes(CA-41, TA-41, DT-41) prepared from AA4123 fabricated the insulating layer since the strong interaction between surface of Ag powder and carboxyl group(COOH) of AA4123 interfered with the formation of conduction path among Ag powders. The viscosity behavior of Ag pastes exhibited shear-thinning flow in the high shear rate range and the pastes with bad dispersion characteristic demonstrated higher shear-thinning index than those with good dispersity due to the weak flocculated network structure. The output curve of OTFT device with a channel length of 107 ${\mu}m$ using screen-printed S-D electrodes from DT-30 showed good saturation behavior and no significant contact resistance. And this device exhibited a saturation mobility of $4.0{\times}10^{-3}$ $cm^2/Vs$, on/off current ratio of about $10^5$ and a threshold voltage of about 0.7 V.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1991.10a
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• pp.56-59
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• 1991

The polyervstalline $Cu_{0.28}Ag_{0.72}InSe_{4.4}S_{0.6}$ thin films are prepared by vacuum heat treatment of laver, which is deposited by direct resisting vacuum evaporation. From optical absorption spetra, the optical hand gap energy is determined to be 1.5[eV] at room temerature. From electrical method. hole concentration, resistivity and mobility are 9.3*$10^{18}$[$cm^{-3}$], 6*$10^{-2}$[$\Omega$$.$cm], 11.2[$\textrm{cm}^2$/V$.$sec] respectively at room temperature.

• Journal of the Microelectronics and Packaging Society
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• v.12 no.4 s.37
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• pp.307-313
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• 2005

Electromigration behavior in the Sn96.5Ag3.0Cu0.5 solder lines was investigated and compared Sn96.5Ag3.0Cu0.5 with eutectic SnPb. Measurements were made for relevant parameters for electromigration of the solder, such as drift velocity, threshold current density, activation energy, as well as the product of diffusivity and effective charge number (DZ$\ast$). The threshold current density were measured to be $2.38{\times}10^4A/cm^2$ at $140^{\circ}C$ and the value represented the maximum current density which the SnAgCu solder can carry without electromigration damage at the stressing temperatures. The electromigration energy was measured to 0.56 eV in the temperature range of $110-160^{\circ}C$. The measured products of diffusivity and the effective charge number, DZ$\ast$ were $3.12{\times}10^{-10} cm^2/s$ at $110^{\circ}C$, $4.66{\times}10^{-10} cm^2/s$ at $125^{\circ}C$, $8.76{\times}10^{-10} cm^2/s$ at $140^{\circ}C$, $2.14{\times}10^{-9}cm^2/s$ at $160^{\circ}C$ SnPb solder existed incubation stage, while SnAgCu did not have incubation stage. It was thought that the diffusion mechanism of SnAgCu was different from that of SnPb.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.2
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• pp.139-144
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• 2001

In this study, we have investigated the photoinduced birefringence of Ag plarized-photodoping in double-layer of Ag doped chalcognide thin films and dependence of polarization states in chalcogenide thin films. Also, we have investigated the polarization dependence of photoinduced birefringence and the anisotropy of absorption in an amorphous As$\sub$40/Ge$\sub$10/Se$\sub$15/S$\sub$35/ chalcogenide thin films using two 632.8nm He-Ne lasers, which have a smaller energy than the optical energy gap (E$\sub$OP/) of the film, i.e., an exposure of sub-bandgap light (hν$\sub$op/). The photoinduced phenomena of Ag polarized-photodooping increasing the linear dichroism(d), about 84% and birefringence(Δn), about 23%. It will offer lots of information for the photodoping mechanism and analysis of chalcogenide thin films.

• Journal of Preventive Medicine and Public Health
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• v.35 no.2
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• pp.129-135
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• 2002

Objective : The primary objective of this study was to estimate the prevalence of HBsAg-positives in the late 1990's among Korean adults. In addition, we evaluated the association of age, a residential area, a vaccination rate, a family history of chronic liver diseases and a past history of acute liver disease with the seropositivity of HBsAg, and estimated the prevalence of chronic HBV infection by follow-up for 6 month or more. Methods : A total of 10 areas, six metropolitan and four small cities, were selected. In each cities, one health screening center was selected for recruitment of study subjects. The study subjects were enrolled from a general health examination program that is provided by medical insurance companies. Questionnaires on various risk factors were administered to the study subjects. Sera was drawn and tested for HBsAg by radioimmunoassay. HBeAg and ALT were also tested for those of HBsAg positive. The HBsAg positives was retest for HBsAg 6 months later Results : Among the study subjects (n= 1816), the seroprevalence of HBsAg was 5.5% (95% CI=4.5%-6.6%), 7.4% in men (95% CI=5.8-9.4) and 3.6% in women (95% CI=2.5-5.0). A past history of acute liver disease and a family history of chronic liver diseases was shown to be risk factors for HBsAg positivity. Among the 31 HBsAg-positives, negative seroconversion rate was estimated to be 3.2%, Thus, prevalence of chronic HBV infection was estimated to be 5.3% (95% CI=3.7-6.6). Conclusion : In this study, the HBsAg seroprevalence rate was lower than that of the other studies in 1980's, particularly in young adult and women. Considering the public health importance of liver cancer and chronic liver diseases, the further effort is needed to prevent and reduce the HBV infection.

• Korean Journal Plant Pathology
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• v.11 no.3
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• pp.278-281
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• 1995

An isolate of Rhizoctonia solani AG 2-2(IV) from zoysiagrass was examined on development of its teleomorph by the modified soil-on-agar culture method. The most effective growth medium for sporulation was Czapek's 1/2 agar medium added with yeast extract and peptone. The characters of teleomorph of R. solani AG 2-2 (IV) are as follows. Hymenia developed on soil surface after the development of vegetative hyphae. Basidia were barrel-shaped, short clavate or obovate and were 11.4~17.9$\times$7.1~11.4 ${\mu}{\textrm}{m}$ (mean : 15.1$\times$9.0 ${\mu}{\textrm}{m}$) in size. Sterigmata were horn-shaped and slightly bent to the inner side and 4.3~18.6 ${\mu}{\textrm}{m}$ (mean : 10.3 ${\mu}{\textrm}{m}$) in size. Two to four sterigmata developed on each basidium. Basidiospores were obovate, ellipsoid to oblong-ellipsoid, hyaline, smooth, thin walled, with an apiculus, and 3.6~10.4$\times$2.9~5.7 ${\mu}{\textrm}{m}$ (mean : 7.8$\times$4.4 ${\mu}{\textrm}{m}$) in size.