• Korean Journal of Materials Research
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• v.12 no.9
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• pp.706-711
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• 2002

High-pure tantalum powder was fabricated through Na reduction process and has been produced by using $K_2$TaF$_{7}$, and KCI, KF for raw material and diluent, respectively. A raw material and diluent were charged at the hestalloy bomb by the weight rate of 1:2, 1:1, 1:0.5 and 1:0.25 each other, investigated properties of morphology, chemical composition and yield and particle size after reduced. Ta metal has been achieved by reduction of $K_2$$TaF_{7}$ 500g with 1% sodium in excess of stoichiometric amount in the charge at a reduction temperature of $850^{\circ}C$ for 3hours. According to amount of the diluent, a formation of the powder doesn't have an effect. The diluent prevented the temperature rising caused from the heat of reaction and it maintained the speed of reducing reaction. But in the mixture ratio of raw material and diluent in the 1 : 2 and 1 : 0.25, an oxide and partially not reacted K were detected. As the amount of diluent increased, the size of tantalum powder decreased. According as raw material and the mixture ratio of diluent change from 1:0.25 to 1:2, the size is decreased from 5$\mu\textrm{m}$ to 1$\mu\textrm{m}$, and a particle size distribution which is below 325 mesh in fined powder increases from 71% to 83%. In the case of average size of Tantalum powder which is the mixture ratio (1:0.5), we would get the Ta powder with grain size about 3$\mu\textrm{m}$, which come close to the average size (2~4$\mu\textrm{m}$) of tantalum powder which is used commonly in the present is Ta powder about 3$\mu\textrm{m}$.

• Journal of Sensor Science and Technology
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• v.19 no.5
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• pp.361-368
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• 2010

ACROSS device, which is composed of an implantable microphone, a signal processor, and a vibrating transducer, is a fullyimplantable middle ear hearing device(F-IMEHD) for the recovery of patients with hearing loss. And since a microphone is implanted under skin and tissue at the temporal bones, the amplitude of the sound wave is attenuated by absorption and scattering. And the vibrating transducer attached to the ossicular chain caused also the different displacement from characteristic of the stapes. For the gain control of auditory signals, most of implantable hearing devices with the digital audio signal processor still apply to fitting rules of conventional hearing aid without regard to the effect of the implanted microphone and the vibrating transducer. So it should be taken into account the effect of the implantable microphone and the vibrating transducer to use the conventional audio fitting rule. The aim of this study was to measure gain characteristics caused by the implanted microphone and the vibrating transducer attached to the ossicle chains for the gain compensation of ACROSS device. Differential floating mass transducers (DFMT) of ACROSS device were clipped on four cadaver temporal bones. And after placing the DFMT on them, displacements of the ossicle chain with the DFMT operated by 1 $mA_{peak}$ current was measured using laser Doppler vibrometer. And the sensitivity of microphones under the sampled pig skin and the skin of 3 rat back were measured by stimulus of pure tones in frequency from 0.1 to 8.9 kHz. And we confirmed that the microphone implanted under skin showed poorer frequency response in the acoustic high-frequency band than it in the low- to mid- frequency band, and the resonant frequency of the stapes vibration was changed by attaching the DFMT on the incus, the displacement of the DFMT driven with 1 $mA_{rms}$ was higher by the amount of about 20 dB than that of cadaver's stapes driven by the sound presssure of 94 dB SPL in resonance frequency range.

• Korean Journal of Materials Research
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• v.9 no.12
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• pp.1196-1204
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• 1999

We have carried out copper MOCVD(metalorganic chemical vapor deposition) onto the reactive sputtered PVD-TiN and rapid thermal converted RTP-TiN substrates using direct liquid injection for effective delivery of the (hfac)Cu(vtmos) [$C_{10}H_{13}O_{5}CuF_{6}$Si: 1,1,1,5,5,5-hexafluoro-2,4- pentadionato (vinyltrimethoxysilane) copper (I)] precursor. Especially, the influences of deposition conditions and the substrate type on growth rate, crystal structure, microstructure, and electrical resistivity of copper deposits have been discussed. It is found that the film growth with 0.2ccm precursor flow rate become mass-transfer controlled up to Ar flow rate of 200sccm and pick-up rate controlled at a vaporizer above 1.0Torr reactor pressure. The surface-reaction controlled region from 155 to 225$^{\circ}C$ at 0.6Torr reactor pressure results in the apparent activation energies of 12.7~14.1kcal/mol, and above 224$^{\circ}C$ the growth rate with $H_2$ addition could be improved compared to the pure Ar carrier. The Cu/RTP-TiN structures which have high copper nucleation density in initial stage of growth show more pronounced (111) preferred orientations and lower electrical resistivities than those on PVD-TiN. The variation of electrical resistivity with substrate temperature reflects the three types of film microstructure changes, showing the lowest value for the deposit at 165$^{\circ}C$ with small grains of good contacts.

• Polymer(Korea)
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• v.36 no.1
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• pp.22-28
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• 2012

Functionalized graphene/epoxy composites were prepared to miprove thermal conductivities of epoxy composites and to maintain electrical insulating property. Graphene oxide (GO) was prepared using Hummers method, and then GO was reacted with aluminum isopropoxide to functionalize $Al(OH)_3$ layer onto GO surface by a simple sol-gel method (Al-GO). GO and Al-GO were characterized by X-ray photoelectron spectroscopy, field emission scanning electron microscopy and transmission electron microscopy. The analyses confirm that GO was coated with a large and dense coverage of $Al(OH)_3$. GO and Al-GO (1 and 3 wt%) were embedded in bisphenol A (DGEBA) to investigate the effects of electrical insulating property. Electrical resistivity showed that Al-GO had better insulating property than GO. Further, the thermal conductivity of GO and Al-GO/epoxy composites was higher than that of neat epoxy resins. In particular, the thermal conductivity of Al-GO/bisphenol F (DGEBF) improved by 23.3% and Al-GO/DGEBA enhanced by 21.8% compared with pure epoxy resins.

• Korean Journal of Breeding Science
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• v.41 no.3
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• pp.236-243
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• 2009

This study was conducted to develop a japonica-type rice cultivar with brown planthopper (BPH) resistance using DNA markers. A doubled haploid (DH) population consisting of 120 pure-lines was established by anther culture of $F_1$ hybrids between 'Samgang', a Tongil type BPH resistance cultivar, and 'Nagdong', a japonica cultivar. To determine the map position of genes responsible for BPH resistance in rice, a genetic map was constructed based on 120 DH lines. A total of 162 molecular markers were classified into 12 linkage groups, covering 1,884 Kosami centimorgan (cM) with an average of 11.6 cM. Five QTLs (qBPR3, qBPR6, qBPR7, qBPR8, and qBPR12) associated with BPH resistance were identified and mapped on chromosomes 3, 6, 7, 8, and 12, respectively, using the genetic map constructed in this study. To analyze the relationship between BPH resistance and agronomic traits, a total of eight QTLs related to the agronomic traits were detected on 12 rice chromosomes. In an analysis of relationships, three QTLs (qBPR3, qBPR7, and qBPR8) showed a linkage with tested agronomic traits. A QTL (qBPR3) located on chromosome 3 (RM282-3023) was closely linked to culm length (qCL3). The QTL (qBPR8) for BPH resistance on the short arm of chromosome 8 also overlapped the region detected in culm length (qCL8).

• Resources Recycling
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• v.30 no.1
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• pp.66-76
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• 2021

Electric arc furnace dust (EAFD) contains compounds, such as oxides and chlorides, including large quantities of Zn, Pb and Fe. An efficient and stable method for the extraction of metal elements from EAFD is the Rotary Kiln Process. This method is used to recover Zn in the form of crude ZnO (approximately 60%) via the addition of a reducing agent (coke, anthracite) and limestone (for basicity control) to EAFD. This process is commonly used in industry as well as in research and development. Currently, this method is used in many Korean commercial plants, producing approximately 150,000 tons of Crude ZnO per year. The majority of Zn is found in crude ZnO (approximately 76%). In addition components such as Pb, Cd, Sn, In, Fe, Cl, and F are present as oxides, chlorides, and alkaline compounds. This elements have an adverse effect on the zinc smelting process. Therefore, a refining process that eliminates these impurities is essential. In this study, we developed a process technology that efficiently separates Zn and Pb from byproducts (mainly chlorides). A bag filter was used to collect Zn and Pb generated during the dry purification process of crude ZnO. Pure components were recovered as metals or metal carbonate.

• Journal of the Korea Institute of Building Construction
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• v.19 no.4
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• pp.289-297
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• 2019

Epoxy resin adhesives are currently used as adhesives in buildings. Epoxy resin adhesives, which are organic materials, generate harmful substances when producing adhesives, and toxic substances are high in the residential space after installation. In addition, a large amount of carbon monoxide generated from organic materials in the case of a building fire leads to personal injury. This study evaluates the feasibility of inorganic adhesives using pure inorganic materials such as magnesia, phosphate, and borax as inorganic adhesives to replace existing organic adhesives. As a result of the experiment on the selection of adequate phosphate and the characteristics of the addition rate of borax used as a retarder, the potassium phosphate monobasic was obtained as a suitable phosphate and the characteristics according to the borax addition rate were compared with the quality standard of KS F 4923 The hardening shrinkage and heat change rate satisfied the quality standards. The tensile strength was satisfactory when the borax addition rate was 4% or more, but the adhesive strength did not meet the quality standards. Further studies are needed to improve adhesion strength.

• Korean journal of applied entomology
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• v.59 no.4
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• pp.371-382
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• 2020

The A, C, F colonies of Apis mellifera ligustica Spin. and D, V colony of Apis mellifera caucasia Gorb. bees were collected from 2005-2007. Consequently, inbred lines were derived from the bees of original colonies by matting in the isolated island with due regard for pure breeding. This project helps in the selection of colonies with higher production capacity, aiming to improve honey and royal jelly production and breeding programs. Twenty-three standard morphological traits of honeybee were evaluated, and samples were compared with the data of the two original subspecies. The result suggested that 8 traits partly preserved in bees of inbred lines, and the bees from A. m. ligustica preserved more traits than bees from A. m. caucasia. Among the studied inbred lines, the F line is distinguished by an increase in leg parameters, considered as a favorable phenotypic trait of inbred lines. Importantly, bred of beelines in the same area can be classified as remote and isolated areas. Therefore, we observed differences of inbred lines with the origin subspecies in description acquired with morphometric characteristics as a result of adaptation, breeding, purebred individual lines used as an important resource for breeding novel cross-breeding colonies.

• Journal of Practical Agriculture & Fisheries Research
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• v.23 no.2
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• pp.25-32
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• 2021

There is a need to breed and distribute of domestic varieties for Lilium longiflorum because most of the lily bulbs cultivated in Korea were imported from foreign country. The L. longiflorum 'Ace' and 'Nellie White' collected from 1996 had been self-crossed from 1996 to 2010. In 2012, the L. longiflorum 'Bright LoSong' was developed as a F₁ hybrid crossed between 'L₂-17-4' and 'L₂-16-6' that obtained by 7th self-fertilization. The 'Bright LoSong' was tested for homogeneity, regional adaptability test, consumer preference show from 2014 to 2015, and it was registered in 2017. The flower of 'Bright LoSong' is a trumpet shaped single flower with no spots.It has 5.8 flowers per plant, which is a relatively many number compared control 'Mount Carmel', Its flower diamater is 9.8cm, relatively a bit small size. And the flower inflorescence has umbel or raceme while the attitude of longitudinal axis is horizontal. The plant height is 38.4cm with 30.8 leaves per plant and 1.9cm of the leaf width. 'Bright LoSong' has a longer flowering period because of relatively small diameter or many number of flowers than those of the control 'Mount Carmel'. Thus, the 'Bright LoSong' showed a high consumer preference, and the cultivar has the advantage of being able to reproduce since the parents are pure lines.

• Korean Journal of Radiology
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• v.23 no.1
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• pp.112-123
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• 2022

Objective: To investigate the relationship between ¹⁸F-FDG PET/CT semi-quantitative parameters and the International Association for the Study of Lung Cancer, American Thoracic Society/European Respiratory Society (IASLC/ATS/ERS) histopathologic classification, including histological subtypes, proliferation activity, and somatic mutations. Materials and Methods: This retrospective study included 419 patients (150 males, 269 females; median age, 59.0 years; age range, 23.0-84.0 years) who had undergone surgical removal of stage IA-IIIA lung adenocarcinoma and had preoperative PET/CT data of lung tumors. The maximum standardized uptake values (SUVmax), background-subtracted volume (BSV), and background-subtracted lesion activity (BSL) derived from PET/CT were measured. The IASLC/ATS/ERS subtypes, Ki67 score, and epidermal growth factor/anaplastic lymphoma kinase (EGFR/ALK) mutation status were evaluated. The PET/CT semi-quantitative parameters were compared between the tumor subtypes using the Mann-Whitney U test or the Kruskal-Wallis test. The optimum cutoff values of the PET/CT semi-quantitative parameters for distinguishing the IASLC/ATS/ERS subtypes were calculated using receiver operating characteristic curve analysis. The correlation between the PET/CT semi-quantitative parameters and pathological parameters was analyzed using Spearman's correlation. Statistical significance was set at p < 0.05. Results: SUVmax, BSV, and BSL values were significantly higher in invasive adenocarcinoma (IA) than in minimally IA (MIA), and the values were higher in MIA than in adenocarcinoma in situ (AIS) (all p < 0.05). Remarkably, an SUVmax of 0.90 and a BSL of 3.62 were shown to be the optimal cutoff values for differentiating MIA from AIS, manifesting as pure ground-glass nodules with 100% sensitivity and specificity. Metabolic-volumetric parameters (BSV and BSL) were better potential independent factors than metabolic parameters (SUVmax) in differentiating growth patterns. SUVmax and BSL, rather than BSV, were strongly or moderately correlated with Ki67 in most subtypes, except for the micropapillary and solid predominant groups. PET/CT parameters were not correlated with EGFR/ALK mutation status. Conclusion: As noninvasive surrogates, preoperative PET/CT semi-quantitative parameters could imply IASLC/ATS/ERS subtypes and Ki67 index and thus may contribute to improved management of precise surgery and postoperative adjuvant therapy.