• 한국분말재료학회지
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• 제24권4호
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• pp.275-278
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• 2017

In the present work, we apply a technique that has been used for the expansion of graphite to multiwall carbon nanotubes (MWCNT). The nanotubes are rapidly heated for a short duration, followed by immersion in acid solution, so that they undergo expansion. The diameter of the expanded CNTs is 5-10 times larger than that of the as-received nanotubes. This results in considerable swelling of the CNTs and opening of the tube tips, which may facilitate the accessibility of lithium ions into the inner holes and the interstices between the nanotube walls. The Li-ion storage capacity of the expanded nanotubes is measured by using the material as an anode in Li-ion cells. The result show that the discharge capacity of the expanded nanotubes in the first cycle is as high as 2,160 mAh/g, which is about 28% higher than that of the un-treated MWCNT anode. However, the charge/discharge capacity quickly drops in subsequent cycles and finally reaches equilibrium values of ~370 mAh/g. This is possibly due to the destruction of the lattice structures by repeated intercalation of Li ions.

• 생약학회지
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• 제6권1호
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• pp.43-47
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• 1975

Attempts were made to determine the characteristics of the morphology of Codonopsis lanceolata $T_{RAUT's}$ root. Its saponin and crude powder were examined by foaming and hemolytic tests and by observing transverse sections: 1) The cork-layer was consisted of multiple cells, and some of the cork cells contained monoclinic prism crystals of calcium oxalates. 2) The vascular bundle was formed of radial arrangement by the preminentic bursting pith and the irregular cambium ring with the abnormal growth. 3) The latex vessel and latex of the cortex were brown-gray or yellowish-brown. The latex vessel and sieve tube were consisted of the independent aggregates which had a number of layers. It had much more independent aggregates than Platycodi Radix. 4) The xylem was less than the phloem portion. The thick-walled vessels which had one to five lines ware more distributed than in Platycodi Radix. 5) The inulin distribution on a piece of section which is dipped in alcohol was observed through out the tissues, but starch grain was not found in it. 6) The duration time of foaming reaction of the crude powder in test tubes was shorter than that of Platycodi Radix. Foaming index of the foaming test of five percent decoctions was 3.33, 7) In the hemolytic test which used 10 percent decoction and one percent saponin solution, hemolytic action was very weak.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.163-164
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• 2005

Round shape Bi2212/Ag is isotropic and can be fabricated Rutherford cable to transport high current. Bi2212/Ag round wires with various Ag ratio were fabricated using powder-in-tube process. Double stacked 385 (55\times$7) filamentary wire of various wire diameter was heat-treated at various melting temperature. Wires which have Ag ratio of 0.3 and 0.42 of Ag tube for monofilament show similar critical current density. As average filament diameter decreases from 33 to 16 \mu$m, critical current density of wires increase, and in case of 16 ${\mu}m$ and $T_m$ 890$^{\circ}C$, critical current density was 2,062 $A/mm^2$ at 4.2 K, 0 T.

• 한국대기환경학회지
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• 제20권3호
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• pp.411-419
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• 2004

Titania particles are widely used as a photocatalyst to treat various contaminants in air and water. Titania particles were formed by vapor-phase oxidation of titanium tetraisopropoxide (TTIP) in a tube furnace between 773 and 1,273 K. The effect of process variables such as furnace temperature, flow rate of carrier air, and flow rate of sheath air on powder size and phase characteristics was investigated using a scanning mobility particle sizer (SMPS), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The size distribution of synthesized titania particles was characterized with mode diameter and peak concentration. The mode diameter ranging from 20 to 80 nm decreased with increasing flow rates of sheath air and carrier air, and increased with increasing furnace temperature. The peak concentration increased with increasing flow rates of sheath air and carrier air The best synthetic condition for high production rate can be derived from the experimental data set represented by mode diameter and peak concentration. The crystal structure of synthesized titania particles was found to be anatase phase, ensuring high photocatalytic potential.

• Journal of Chest Surgery
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• 제24권6호
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• pp.570-578
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• 1991

The spontaneous pneumothorax is the sudden collapse of the lung usually by air leakage from the ruptured sub-pleural bleb and has high recurrence rate. For prevention against recurrence, many drugs such as tetracycline, talcum powder, quinacrine, etc. have been used but the effects are not satisfactory. We reduced the recurrence rate successfully by the fibrin glue instillation through the chest tube. From the January 1989 to September 1990, we have managed 65 patients of spontaneous pneumothorax with closed thoracostomy and fibrin glue[fibrinogen 1gm/50ml with approtinin 3, 000kIU /ml, thrombin 5, 000IU /ml in 3% each 10ml] instillation through the chest tube. And we compared the results with those of 106 patients of spontaneous pneumothorax who were managed only by the closed thoracostomy from January 1985 to December 1988. Only the patients who visited our hospital with recurrence were considered as the recurred cases but the others were considered as not recurred. And the removal of chest tubes usually done 3 days after cessation of air leakage or 2 days after fibrin glue instillation Statistical analysis was done by X2-test. The results were as followings: 1. The recurrence rate of fibrin glue instillation group was lower than that of non-instillation group[1st attack: 15.1% versus 27.6% p<0, 05, the 2nd attack: 33.3% versus 73.7% p<0.01, the total 18.5% versus 35.8% p<0.01]. 2. The mean duration of chest tube drainage in the fibrin glue instillation group was shorter than non-instillation group[4.24$\pm$1.36 days versus 4.48$\pm$1.73 days p<0.05]. 3. The mean duration of hospitalization was shorter in the instillation group [8.12$\pm$3.5 days versus 10.8$\pm$3.8 days p<0.05] The complications were transient mild fever, chest pain, pleural effusion in 46 cases of 65 patients, but those didn`t make any problem. We concluded that the fibrin glue is effective in the reduction of recurrence rate, obliteration of air leakage and duration of hospitalization.

• 한국식품영양학회지
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• 제29권5호
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• pp.692-697
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• 2016

This study was aimed to develop a gruel using rice extrudates and to evaluate physicochemical properties of Tarakjuk (milk porridge; MP) prepared with milk (M) and rice powder (RP, control), rice extrudate (RE), or enzyme treated rice extrudates (ETR). Pasting property of ETR was significantly different from those of RP or RE with significantly low peak viscosity, breakdown and setback values in the ETR sample. Viscosity of MP prepared with ETR was also significantly low, as compared to that of control (> 900 cP). The total solids and spreadability of MP with ETR was higher than those with RP or RE. Hunter color values varied significantly depending on enzyme treatment levels in ETR samples with enzyme dose-dependent increase in b-value. Average starch digestibility of ETR sample was higher by 10.2% than that of control sample. DPPH radical scavenging activities of ETR samples were greater than those of RE or RP. These results indicated that ETR could be beneficial for preparing easy-drink and diet food with higher starch digestibility and fluidity, especially for gastric tube-fed patients.

• 한국분말재료학회지
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• 제23권2호
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• pp.102-107
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• 2016

We demonstrate the electrochromic properties of $TiO_2$ nanotubes prepared by an anodization process and investigate the effects of heat treatment and viologen incorporation on them. The morphology and crystal structure of anodized $TiO_2$ nanotubes are investigated by scanning electron microscopy and X-ray diffraction. As-formed $TiO_2$ nanotubes have straight tubular layers with an amorphous structure. As the annealing temperature increases, the anodized $TiO_2$ nanotubes are converted to the anatase and rutile phases with some cracks on the tube surface and irregular morphology. Electrochemical results reveal that amorphous $TiO_2$ nanotubes annealed at $150^{\circ}C$ have the largest oxidation/reduction current, which leads to the best electrochromic performance during the coloring/bleaching process. Viologen-anchored $TiO_2$ nanotubes show superior electrochromic properties compared to pristine $TiO_2$ nanotubes, which indicates that the incorporation of a viologen can be an effective way to enhance the electrochromic properties of $TiO_2$ nanotubes.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.179-179
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• 2016

A radio-frequency (RF) Inductively Coupled Plasma (ICP) torch system was used for boron-nitride nano-tube (BNNT) synthesis. Because of electrodeless plasma generation, no electrode pollution and effective heating transfer during nano-material synthesis can be realized. For stable plasma generation, argon and nitrogen gases were injected with 60 kW grid power in the difference pressure from 200 Torr to 630 Torr. Varying hydrogen gas flow rate from 0 to 20 slpm, the electrical and optical plasma properties were investigated. Through the spectroscopic analysis of atomic argon line, hydrogen line and nitrogen molecular band, we investigated the plasma electron excitation temperature, gas temperature and electron density. Based on the plasma characterization, we performed the synthesis of BNNT by inserting 0.5~1 um hexagonal-boron nitride (h-BN) powder into the plasma. We analysis the structure characterization of BNNT by SEM (Scanning Electron Microscopy) and TEM (Transmission Electron Microscopy), also grasp the ingredient of BNNT by EELS (Electron Energy Loss Spectroscopy) and Raman spectroscopy. We treated bundles of BNNT with the atmospheric pressure plasma, so that we grow the surface morphology in the water attachment of BNNT. We reduce the advancing contact angle to purity bundles of BNNT.

• 한국기계가공학회지
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• 제9권3호
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• pp.42-48
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• 2010

The aim of this study is to investigate the influence of driving atomizing nozzle position, the slope of sludge entering tube and supplying air flow rate on the performance of sludge air dryer. This paper deals with optimization of the geometry of the atomizing nozzle for sludge drying using computational fluid dynamics and drying performance test using pilot air dryer. The air drying system was composed of the atomizing nozzle which made high-speed fluid field. dewatered cake was crushed at the high-speed zone as the first step and formed intto dried powder of sphere shape by the collision between particles at the circling zone. The CFD analysis results show when the slope of entering sludge tube is smaller, suction air amount is increased. It is shown that the developed atomizing nozzle is very excellent in the drying performance through pilot test.

• 한국세라믹학회지
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• 제43권12호
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• pp.768-774
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• 2006

The microstructure of Ni-YSZ cermets was controlled with fine and coarse starting powders (NiO and YSZ) to obtain a optimum strong and conductive tubular anode support for SOFCs. Three types of cermets with different microstructures, i.e., coarse Ni-fine YSZ, fine Ni-coarse YSZ, and fine Ni-fine YSZ, were fabricated to investigate their electrical and mechanical properties. The cermets from fine NiO powder showed high electrical conductivity due to the enhanced percolation of Ni particles. The cermet by foe Ni and coarse YSZ showed excellent electrical conductivity (>1000 S/cm) despite its high porosity $(\sim40%)$ but it showed poor mechanical strength due to the lack of percolation by YSZ particles and due to large pores. Thus fine NiO and YSZ powders were used to make strong and conductive Ni-YSZ support tube by extrusion. The microstructure of the anode tube was modified by the amount of polymeric additives and carbon black, a pore former. Ni-YSZ tube (porosity $\sim34%$) with the finer microstructure showed better performance both in electrical conductivity (>1000 S/cm) and fracture strength $(\sim140\;MPa)$. Either flat or circular NiO-YSZ tubes with the length from 20 to 40cm were successfully fabricated with the optimized composition of materials and polymeric additives.