• Asian Journal of Turfgrass Science
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• v.9 no.3
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• pp.235-252
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• 1995

Turfgrass Rhizoctonia blight is a severe disease in golf courses in Korea. Attempts were made in 1989 to 1994 to identify the Rhizoctonia species associated with turfgrass blights and also to examine their epidemiology. A total of 120 Rhizoctonia isolates collected were identified as R. solani AG1, R. solani AG2-2, R. cerealis(AG-D) and R. oryzas from brown patch, large patch, yellow patch and white patch, re-spectively. R. solani AG1 was mostly associated with brown patch of cool-season grasses. and most frequently isolated in June through July and also in September. R. solani AG2-2 was isolated exclusively from zoysiagrasses from April to November, most frequently in June through July and October through November. R. cerealis was isolated frequently from both creeping hentgrass in March through April and in November, and zoysiagrass in April and July. Thermophilic R. oryzae was isolated only from creeping bentgrass in August, although with very low frequency. R. solani AG2-2 was strongly pathogenic specifically to Korean lawngrasses(Zoysia japonica, Z.matrella, Z. tenuifolia), but non-pathogenic to creeping bentgrass(Agrostis palustris), bermudagrass (Cynodon dactylon), Kentucky bluegrass(Poa pratensis), perennial ryegrass(Lolium prenne), and creeping red fescue(Festuca rubra subsp. ruhra L.). R. cerealis was strongly pathogenic to zoysiagrass and bentgrass only, but was isolate-specific i.e., from non-pathogenic to pathogenic, for other turfgrasses. The mycelial growth was optimum at relatively high temperature ranges of 25~30$^{\circ}C$ for R.solani AG1, AG2-2 and R. oryzae, while the mycelial growth of R. cerealis was initiated at $^{\circ}C$ and almost ceased at or above $^{\circ}C$.

• International Journal of Industrial Entomology and Biomaterials
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• v.22 no.2
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• pp.39-44
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• 2011

To evaluate the growth rate of larval and pupal parameters of silkworm Bombyx mori fed with Silver Nanoparticles (AgNps) treated $MR_2$ mulberry leaves, the following works have been considered. The AgNp was synthesized by chemical reduction method, it was diluted by different concentrations such as 25%, 50%, 75% and 100% (without dilution). Fresh mulberry leaves (Morus alba L.) were sprayed by each concentration and were fed to silkworms, from $3^{rd}$, $4^{th}$ and $5^{th}$ instar, five feedings/day. Group $T_1$ larvae received $MR_2$ mulberry leaves sprayed with distilled water and served as control, group $T_2$, $T_3$, $T_4$ and $T_5$ larvae received 25%, 50%, 75% and 100% AgNps sprayed mulberry leaves, respectively. Silkworm larvae fed on M. alba ($MR_2$) leaves sprayed with 25% concentration of AgNps (group $T_2$) was significantly increased the larvae and cocoon length, width and weight as compared to those fed on control (group $T_1$) $MR_2$ mulberry leaves and other groups ($T_3$, $T_4$ and $T_5$). Hence, 25% AgNps dose was fixed as an effective dose. It has been observed from the present study that 25% AgNps treated (group $T_2$) leaves fed by silkworms have enhanced the larval and pupal growth and quantity of silk production than control.

• Korean Journal of Materials Research
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• v.17 no.8
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• pp.402-407
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• 2007

In electronics manufacturing processes, soldering process has generally been used in surface mounting technology. Because of environmental restriction, lead free solders as like a SnAgCu ternary system are being used widely. After soldering process, the formation and growth of intermetalic compounds(IMCs) are formed in the interface between solder and Cu substrate as follows isothermal temperature and time. In this studies, therefore, we investigated the effects of the Cu substrate thickness on the IMC formation and growth of Sn-40Pb/Cu and Sn-3.0Ag-0.5Cu/Cu solder joints, respectively. The effect of the Cu thickness in PCB Cu pad and pure Cu plate was analyzed as measuring of thickness of each IMC. After solder was soldered on PCB and Cu plate which have different Cu thickness, we measured the IMC thickness in solder joints respectively. Also we compared with the effectiveness of Cu thickness on the IMC growth. From these results, we calculated the activation energy.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.6
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• pp.493-501
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• 1998

$YBa_2Cu_3O_X$ samples were fabricated by MPMG(Melt Powdered Melt Growth). Intitial composition of the mixed powders were prepared as follow ; $YBa_2Cu_3O_X$ : $Y_2BaCuO_5$ = 1:0, 1:0.2, 1:0.3, 1:0.4. After the first melt and cooling, 5wt% to 20wt% fo Ag power was added to the powder. Effects of the different initial $Y_2BaCuO_5$ and Ag addition amount on $J_c$ and magnetization of $YBa_2Cu_3O_X$ fabricated by MPMG method were investigated. The critical current density increased with the amount of $Y_2BaCuO_5$ and Ag. It was also observed that the difference between negative and positive magnetization in the magnetization hysteresis measurement at 77K was larger than the case where $Y_2BaCuO_5$and Ag were not added to the $YBa_2Cu_3O_X$ powders. It is concluded that $Y_2BaCuO_5$ sample with 40wt% amount of $Y_2BaCuO_5$ and 20wt% amount of Ag has not only the largest $J_c$ but also the improved pinning effect.

• Korean Journal Plant Pathology
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• v.14 no.3
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• pp.260-267
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• 1998

This study was undertaken to find a new formulation of soil amendment, and selection of antogonists and to effectively control brown and large patch of turfgrasses caused by Rhizoctoniz solani AG1-1 and AG 2-2. Fourteen inorgainc chemicals (1%, w/w) were added individually in vitro, and some chemicals showed suppressiveness to R. solani. Alum suppressed effectively mycelial growth of R. solani in the range of 17 to 77% as compared with control. The four chemicals such as Al2(SO4)3, alum, CaO, and NH4NO3 were finally selected. Out of three organic compounds, composted pine bark (CPB) showed prominent suppressive effect as compared with milled alfalfa and pine leaves. After inoculation of R. solani isolates AG-1 and AG2-2 on the turf seedlings, water soaked lesions and blight symptoms were developed on the whole seedlings. According to inhibition zone method, mycelial growth of the fungus were greatly suppressed by culture filterates of the antagonists, Gliocladium virens (Gl1-) and Pseudomonas sp. (P713). CPB soil amendment mixed with antagonists (1% w/w) controlled not only brown and large patch of turfgrasses, but also promote the good growth of the seedlings. In addition, the controlling effect was maintained more than 30 days. Especially, the controlling effect of two antagonists was similar to Cㅖㅠ soil amendment with the antagonists and also stimulated a favorable growth of the seedlings. Therefore, its is expected that continuous control of Rhizoctonia blight of turfgrasses can be obtained in field by subsequent applications of the antagonists.

• Journal of the Microelectronics and Packaging Society
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• v.17 no.1
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• pp.81-88
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• 2010

Thermal annealing and electromigration test were performed at $150^{\circ}C$ and $4{\times}10^3\;A/cm^2$ conditions in order to investigate the effect of PCB surface finishs on the growth kinetics of intermetallic compound (IMC) in Sn-3.0Ag-0.5Cu solder bump. The surface finishes of the electrodes of printed circuit board (PCB) were organic solderability preservation (OSP), immersion Sn, and electroless Ni/immersion gold (ENIG). During thermal annealing, the OSP and immersion Sn show similar IMC growth velocity, while ENIG surface finish had much slower IMC growth velocity. Applying electric current accelerated IMC growth velocity and showed polarity effect due to directional electron flow.

• Journal of Welding and Joining
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• v.25 no.2
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• pp.82-88
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• 2007

Sn-3.0Ag-0.5Cu lead fee solder was generally utilized in electronics assemblies. But it is insufficient to research about activation energy(Q) that is applying to evaluate the solder joint reliability of environmental friendly electronics assemblies. Therefore this study investigated Q values which are needed to IMC formation and growth of Sn-3.0Ag-0.5Cu/Cu and Sn-40pb/Cu solder joints during aging treatment. We bonded Sn-3.0Ag-0.5Cu and Sn-40Pb solders on FR-4 PCB with Cu pad$(t=80{\mu}m)$. After reflow soldering, to observe the IMC formation and growth of the solder joints, test specimens were aged at 70, 150 and $170^{\circ}C$ for 1, 2, 5, 20, 60, 240, 960, 15840, 28800 and 43200 min, respectively. SEM and EDS were utilized to analysis the IMCS. From these results, we measured the total IMC$(Cu_6Sn_5+Cu_3Sn)$ thickness of Sn-3.0Ag-0.5Cu/Cu and Sn-40Pb/Cu interface, and then obtained Q values for the IMC$(Cu_6Sn_5,\;Cu_3Sn)$ growth of the solder joints.

• KSBB Journal
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• v.17 no.1
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• pp.63-67
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• 2002

Silver-alginate and copper-alginate were prepared with Na-alginate extracted from marine brown algae(Sargassum fluitans). The antibacterial effect of Ag-alginate or Cu-alginate against Staphylococcus aureus and Escherichia coli was carried out by measuring optical density of liquid culture at 600 nm. The cell growth of Staphylococcus aureus and Escherichia coli was very active at pH 7, and was inhibited by adding Ag-alginate with more than 0.006 wt.% of silver content. The antibacterial effect of Ag-alginate against S. aureus and E. coli was better than that of Cu-alginate at the same metal concentration. The cell growth of S. aureus was less inhibitory than E. coli at the same concentration of Ag-alginate. The cell growth of S. aureus and E. coli was also influenced by the characteristics of counter ion of silver.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.27 no.4
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• pp.162-166
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• 2017

Thermoelectric compounds of $Zn_{1-x}Ag_xSb$ with x = 0~0.2 were prepared by vacuum melting and quenching process and their crystal phases and thermoelectric properties were examined. It was found that free metallic Sb phases were formed in the compound with x = 0.05, leading to increasing the electrical conductivities. The power factors were significantly affected by the electrical conductivity rather than Seebeck coefficient. When x > 0.05, the peak intensities of $Ag_3Sb$ phases in XRD patterns were increased and those of free Sb phases were weakened. These changes of second phases resulted in decreasing the electrical conductivities and the power factors and became more obvious in the compound with x = 0.2.

• Journal of the Korean Vacuum Society
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• v.1 no.1
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• pp.126-133
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• 1992

This study deals with the crystal growth and the optical characteristics of CdS thin films activatedby silver. CdS:Ag thin films were deposited by using an electron beam evaporation(EBE) technique in vacuumof 1.5X 10-'torr, voltage of 4 kV, current of 2.5 mA and substrate temperature of 250$^{\circ}$C CdS:Ag photoconductivefilms prepared by EBE method show high photoconductivity after annealing at about 550"c for 0.5 h in air andAr gas.The grain size of CdS:Ag thin films annealed in Ar atmosphere (1 atm) was grown over 1 ym and the thicknessof the films is 4-5 pm. The analysis of X-ray diffraction patterns shows that the crystal structures are hexagonal.The diffraction line by (00.2) plane can only be observed, indicating that c-axis of hexagonal grows preferentiallyperpendicular to the substrate. The profiles of photoluminescence spectra of CdS:Ag films show Gaussian typecurves at room temperature, the maximum peak spectral sensitivity of CdS:Ag is located at the wavelength of520 nm.We annealed CdS:Ag thin films in air and Ar vapor in order to make the CdS photoconductors having theintensive photocurrent, the broad distribution of the photocurrent spectrum and the large value of the ratioof the photocurrent (pc) to the dark current(dc). We found that CdS:Ag thin films annealed in air atmospherewas the best one.air atmosphere was the best one.