• Journal of Electrical Engineering and Technology
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• v.6 no.6
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• pp.842-848
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• 2011

The current study proposes the design of a hybrid series-parallel resonant converter (SPRC) and a three-stage Cockcroft-Walton voltage multiplier for precisely adjusting the power generated by a continuous wave (CW) $CO_2$ laser. The design of a hybrid SPRC, called LCC resonant converter, is described, and the fundamental approximation of a high-voltage and high-frequency (HVHF) transformer with a resonant tank is discussed. The results of the current study show that the voltage drop and ripple of a three-stage Cockcroft-Walton voltage multiplier depend on frequency. The power generated by a CW $CO_2$ laser can be precisely adjusted by a variable-frequency controller using a DSP (TMS320F2812) microprocessor. The proposed LCC converter could be used to obtain a maximum laser output power of 23 W. Moreover, it could precisely adjust the laser output power within 4.3 to 23 W at an operating frequency range of 187.5 to 370 kHz. The maximum efficiency of the $CO_2$ laser system is approximately 16.5%, and the minimum ripple of output voltage is about 1.62%.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.1
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• pp.55-61
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• 1984

A Korean local maize line, MET, which has multi-ears and tillers has been proved as a potential source for silage production. However, no fundamental genetic nature for the line has been investigated. Therefore, this study was done to find genetic information on the multi-earing and -tillering habits of MET line. MET line and a hybrid. (Mo 17 ${\times}$ B68), with monoculm and single ear per plant were used for production of F$_1$(F$\_$1-12/ and F$\_$1-21/), F$\_$2-12/, F$\_$2-21/, BC$\_$1-12/ and BC$\_$1-21/ generations. From the comparison of reciprocal crosses, it was found that the tillering and earing habits of the MET line are controlled by cytoplasmic factors. The tiller and ear numbers, and barren ears were all characters associated with the MET cytoplasm. The cytoplasmic effect of MET on tiller and ear numb en was not evident in F$_1$ generation, probably because of suppressing effect of heterosis on appearance of tillers or ears. Genetic parameters for the gene action for both tiller and ear number also indicated a lack of mono- or digenic-chromosomal gene effects. The heritability (broad) was very low for both characters. Therefore, it is strongly concluded that the tillering and earing characters of MET line are due to cytoplasmic reasons.

• Journal of the Korean Applied Science and Technology
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• v.31 no.2
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• pp.296-304
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• 2014

For this research, prepared polyurethane dispersion of hard segment type and polyethylene emulsion wax. Use these resin, this article has been analyzed about mechanical properties variation by increasing amount of polyethylene emulsion wax on Lam skin leather and dried film. According to measure data for solvent resistance, PUD had good property. As known in the results, increase of polyethylene wax constant did not influence to big variation of hybrid resin properties. As test of tensile strength, PUD had good tensile characteristic($1.235kg_f/mm^2$) and PUD-EW4 had lowest tensile characteristic($1.022kg_f/mm^2$). As same as tensile characteristic, abrasion test determined PUD(52.225 mg.loss) had highest properties. In elongation case, PUD showed 698 % modulus which was best properties in this experiment.

• The Korean Journal of Ceramics
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• v.1 no.2
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• pp.96-100
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• 1995

Recently, alumina/glass composites have been applied as a substrate material for hybrid IC and LSI multi-chip packaging. In this study, the characterization of sodium borosilicate glasses containing NaF and $AlF_3$ and the preparation of the resulted glass/alumina composites have been examined and the effect of the addition of fluorides on the thermal. and dielectric properties of the sintered composites have been studied. The sintering temperature of specimens was lowered by about 100-$150^{\circ}C$ by the addition of fluorine compared with the specimens without fluorine. The specimens containing fluorine showed slightly lower dielectric constants than those of the specimens without fluorine.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.251-256
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• 2005

This study was performed the heat transportation ratio of three types of the following sandwich panel by KS F 2278(2003) ; Type ${\sharp}1$ : Carbon/epoxy Aluminum Honeycomb and Balsa Core Sandwich Panel(Thickness : 37mm), Type ${\sharp}2$ : Carbon/epoxy Aluminum Honeycomb Core Sandwich Panel(Thickness : 57mm), and Type ${\sharp}3$ : Carbon/epoxy Aluminum Honeycomb Core Sandwich Panel(Thickness : 37mm). Also was performed the heat transportation of next three types of the following sandwich panel by KS F2277(2002) ; Type ${\sharp}4$ and ${\sharp}5$ : 27mm, and 35mm thick-Aluminum Honeycomb Sandwich Panels, and Type ${\sharp}6$ : 27mm thick-Foaming Aluminum Sandwich Panel. It is the larger area between the skin and core, the heat transportation ratio is the higher, and when it is composed of the hybrid composite structure, good insulation property was shown.

• Proceedings of the Turfgrass Society of Korea Conference
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• 2005.04a
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• pp.31-38
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• 2005

본 실험은 한국잔디 신품종 '세녹'(특허출원:10-2003-0072018) 개발에 관한 것이다. 한국에서 수집한 유전자원 중 갯잔디와 금잔디간에 인공교배를 수행해서 F1계통을 얻었다. 작성한 F1계통을 포장상태에서 방임수분을 통해 변이확대를 하였으며, 이들 방임수분 후대에서 선발한 것이 '세녹'이다. '세녹'은 유전적으로 잔디의 녹색도가 진하며, 낮게 자라는 특성이 있고 품질이 우수하며 잎의 강직성이 높다. 엽폭이 3.1mm로 중엽형이며, 초장이 14cm로 낮고, 잎각도가 67.3도로 넓다. 지면으로부터 최하위 엽의 잎 몸 기부까지의 길이가 2cm로 낮은 형태적 특성을 갖고 있어 낮은 잔디깍기에 적응할 수 있는 영양번식형 잔디이다. 또한 RAPD 밴드 특성에서 한국잔디 신품종 세녹(Senock)이 특이 밴드를 갖고있어 식별성이 높다.

• Steel and Composite Structures
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• v.45 no.6
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• pp.877-894
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• 2022

Geopolymer concrete (GPC) has emerged as a feasible choice for construction materials as a result of the environmental issues associated with the production of cement. The findings of this study contribute to the development of machine learning methods for estimating the properties of eco-friendly concrete to help reduce CO₂ emissions in the construction industry. The compressive strength (f_c) of GPC is predicted using artificial intelligence approaches in the present study when ground granulated blast-furnace slag (GGBS) is substituted with natural zeolite (NZ), silica fume (SF), and varying NaOH concentrations. For this purpose, two machine learning methods multi-layer perceptron (MLP) and radial basis function (RBF) were considered and hybridized with arithmetic optimization algorithm (AOA), and grey wolf optimization algorithm (GWO). According to the results, all methods performed very well in predicting the f_c of GPC. The proposed AOA - MLP might be identified as the outperformed framework, although other methodologies (AOA - RBF, GWO - RBF, and GWO - MLP) were also reliable in the fc of GPC forecasting process.

• Korean Journal of Optics and Photonics
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• v.5 no.2
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• pp.333-339
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• 1994

We fabricated a single mode fiber pigtailed PIN-preamplifier front-end receiver module for the high speed optical receiver. Hybrid method was used to integrate GaInAs PIN photodiode and transimpedance type GaAs preamplifier. The capacitance and the diameter of light receiving area of PIN photodiode were 0.35 pF and $20{\mu}m$ respectively. The -3 dB cut-off frequency of PIN-preamplifier module was above 2 GHz, and the sensitivity of the module at 2.5 Gbps NRZ $(PRBS=2^{23}-1)$ signal was -25.2 dBm at $10^{-9}$ BER. > BER.

• Journal of Crop Science and Biotechnology
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• v.11 no.1
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• pp.75-82
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• 2008

Functional stay-green is a beneficial trait that may increase grain yield through the sustained photosynthetic competence during monocarpic senescence in cereal crops. The temporal changes of photosynthesis and related characteristics throughout the grain filling period of a stay-green japonica rice "SNU-SG1" was compared in growth chamber conditions with three high-yielding cultivars(HYVs) and their $F_1$ hybrids with SNU-SG1. SNU-SG1 exhibited a typical characteristic of functional stay-green in terms of chlorophyll degradation and photosynthetic competence during grain filling. According to the photosynthesis-light response curve measured at 10 and 35 d after heading for the flag leaf, SNU-SG1 exhibited higher initial light conversion efficiency and thus higher gross photosynthetic rate at light saturation compared to HYVs. Light saturation point was not different among genotypes, ranging from 1000 to 1500 ${\mu}mol$ photon $m^{-2}s^{-1}$. Net photosynthetic rate at light saturation($P_{max}$) of the upper four leaves in SNU-SG1 was much higher and sustained longer throughout grain-filling than HYVs and $F_1$ hybrids. The sustained high photosynthetic competence of SNU-SG1 during grain filling was ascribed to the longer maintenance of high mesophyll conductance that resulted from not only high chlorophyll content and its delayed degradation but also the slow degeneration of photosystem II(PS II) as judged by chlorophyll fluorescence($F_v/F_m$) of flag leaves. $F_1$ hybrids showed slow degeneration of photosystem II similar to the male parent SNU-SG1 while chlorophyll degradation pattern close to female parents, thus exhibiting a little higher $P_{max}$ than female parents. These results suggest that SNU-SG1 has a typical functional stay-green trait that can be utilized for increasing rice yield potential through the improved dry matter production during grain filling.

• Journal of Microbiology
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• v.39 no.4
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• pp.286-292
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• 2001

During mitosis. the proper segregation of duplicated chromosomes is corrdinated by a spindle check-point. The bifurcated spindle checkpoint blocks cell cycle progression at metaphase by monitoring unattached kinetochores and inhibits mitotic exit in response to the misorientation of the mitotic spin- dle Ibd1p/Bfa1p is a spindle checkpoint regulator of budding yeast in the Bub2p checkpoint pathway for mitotic exit and its disruption abolishes mitotic arrest when proper organization of the mitotic spin-dls inhibited. Ibd1p/Bfa1p localizes to the spindle pole body, a microtublue-organizing center in yeast, and its overexpression arrests the cell cycle in 80% of cells with an enlarged budy at mitosis and in 20 % of cells with multiple buds. In this study, we found that the C-terminus of Ibd1p/Bfa1p phys-ically interacts with Skp1p, a key component of SCF (Skp1/cullin/F-box) complex for ubiquition-medi-ated proteolysis of cel cycle regulatores as well as an evolutionally conserved kinetochore protein for cell cycle progression. A putative F-box motif was found in the C-terminus of Ibd1p/Bfa1p and its function was investigated by making mutants of conserved residues in the motif. These Ibd1p/Bfa1p mutants of a putative F-box interacted with SKp1p in vitro by two-hybrid assays as wild type Ibd1p/Bfa1p. Also these Ibd1p/Bfa1p utants displayed the overexpression phenotypes of wild type Ibd1p, when over-expressed under inducible promoters . These results suggest that a putative F-box motif of Ibd1p/Bfa1p is not essential for the interaction with SKp1p and its function in mitotic exit and cytokinesis.