• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.1
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• pp.81-86
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• 1997

Spray dried powdered juice was processed from concentrated extract of jujube(Zizyphus jujuba MILLER). Spray drying of the extract solution could not be operated to have powder product by itself over whole concentration range and required addition of some carrier or support material. The concentrated extract of 26$^{\circ}$Bx was combined with carrier material solution to have a final concentration of 30$^{\circ}$Bx, and then spray dried. Proper addition level of carrier solid for physical and flavor quality of the powder product was determined to be 1 : 1 ratio to jujube solid. Combined use of maltose and gum arabic produced the best quality product among the studied carrier materials, which were maltose, dextrin, condensed milk and gum arabic. Enzymatic treatment in extraction process could increase the yield by 13~39%, but hurt the sensory quality of powdered juice. Treatment by 0.5% pectinase(0.05 unit/ml) may be used with lesser quality change for improved yield.

• Resources Recycling
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• v.12 no.3
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• pp.46-53
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• 2003

Recycling of aluminum dross is an important issue in the secondary aluminum industries. In this study, aluminum dross generated in the domestic secondary aluminum industry was processed to use it as raw material for producing alumina refractories. Sample dross was classified according to its size. The dross smaller than 1 mm was leached with sodium hydroxide solution to extract the remained aluminum from the dross into the solution. and then aluminum hydroxide precipitate was recovered from the leach liquor. The waste residue in the leaching was washed, dried and roasted. Most remained metallic components in the residue was changed into oxide through the processes. The roasted dross was made into alumina castable refractories by mixing with aggregates and a binder. Bending strength of the tested castable specimen was over $25\;kg/\textrm{m}^2$ and compressive strength over $80\;kg/\textrm{cm}^2$, which satisfied the Korean Standard value respectively. From the results, it was suggested that this process could be applicable to recycling of aluminum dross.

• Korean Journal of Metals and Materials
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• v.56 no.11
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• pp.835-843
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• 2018

In this work, we report a delta rosette strain sensor based on highly stretchable silver nanowire (AgNW) percolation piezoresistors. The proposed rosette strain sensors were easily prepared by a facile two-step fabrication route. First, three identical AgNW piezoresistive electrodes were patterned in a simple and precise manner on a donor film using a solution-processed drop-coating of the AgNWs in conjunction with a tape-type shadow mask. The patterned AgNW electrodes were then entirely transferred to an elastomeric substrate while embedding them in the polymer matrix. The fabricated stretchable AgNW piezoresistors could be operated at up to 20% strain without electrical or mechanical failure, showing a maximum gauge factor as high as 5.3, low hysteresis, and high linearity ($r^2{\approx}0.996$). Moreover, the sensor responses were also found to be highly stable and reversible even under repeated strain loading/unloading for up to 1000 cycles at a maximum tensile strain of 20%, mainly due to the mechanical stability of the AgNW/elastomer composites. In addition, both the magnitude and direction of the principal strain could be precisely characterized by configuring three identical AgNW piezoresistors in a delta rosette form, representing the potential for employing the devices as a multidimensional strain sensor in various practical applications.

• Korean Journal of Materials Research
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• v.29 no.3
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• pp.155-159
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• 2019

Surface plasmon resonance is the resonant oscillation of conduction electrons at the interface between negative and positive permittivity material stimulated by incident light. In particular, when light transmits through the metallic microhole structures, it shows an increased intensity of light. Thus, it is used to increase the efficiency of devices such as LEDs, solar cells, and sensors. There are various methods to make micro-hole structures. In this experiment, micro holes are formed using a wet chemical etching method, which is inexpensive and can be mass processed. The shape of the holes depends on crystal facets, temperature, the concentration of the etchant solution, and etching time. We select a GaAs(100) single crystal wafer in this experiment and satisfactory results are obtained under the ratio of etchant solution with $H_2SO_4:H_2O_2:H_2O=1:5:5$. The morphology of micro holes according to the temperature and time is observed using field emission - scanning electron microscopy (FE-SEM). The etching mechanism at the corners and sidewalls is explained through the configuration of atoms.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.28 no.1
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• pp.23-30
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• 2022

This study investigated the characteristics for rice husk pulverization and surface modification of biomass byproducts composed of rice husk, corn extract gourd, wheat bran, and soybean curd. The size of particles of rice husk was at 6.44 ㎛ and represented the most affordable material for preparing the bio-degradable film among the tested byproducts. The silane treatment and adding 2% of ESO (Epoxidized soybean oil) and 3-aminopropyl triethoxysilane solution mixed in a 1:1 ratio were best to the surface modification and SEM-based particle shape. Above the results, adding 2% of mixed solution after silane treatment of rice husks processed through an air classifying mill (ACM) allows for its use as a raw material of bio-degradable plastic film.

• Journal of IKEEE
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• v.24 no.3
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• pp.699-705
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• 2020

In this study, a facial way to enhance the electrical properties of organic light-emitting diodes (OLEDs) via the solution process doping method based on the poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl) diphenylamine)] (TFB) as a hole transporting layer (HTL) is demonstrated. In the TFB solution of the hole transport material, 1,4,5,8,9,11-hexaazatriphenylene hexacarbonitrile (HAT-CN) was doped by 3 wt% to improve the electrical properties of the HTL. According, the OLED with HAT-CN doped TFB showed the increased current density and luminance at the same driving voltage on behalf of the improved conductivity of HTL, and the reduced turn-on voltage from 13 V to 9 V. Furthermore, the maximum external quantum efficiency was dramatically increased three times from 3.6 to 10.8 % compared to the reference device without appling doping methode.

• Journal of Periodontal and Implant Science
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• v.36 no.2
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• pp.319-334
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• 2006

Mechanical and chemical methods are the two ways to treat the implant surfaces. By using mechanical method, it is difficult to eliminate bacteria and by-products from the rough implant surface and it can also cause the structural change to the implant surface. Therefore, chemical method is widely used in order to preserve and detoxicate the implant surface more effectively. The purpose of this study is to evaluate the effect of tetracylcline-hydrochloride(TC-HCI) on the change of implant surface microstructure according to application time. Implants with pure titanium machined surface, SLA surface and porous surface were used in this study. Implant surface was rubbed with sponge soaked in 50mg/ml TC-HCI solution for $\frac{1}{2}$ min., 1 min., $1\frac{1}{2}$ min., 2 min., and $2\frac{1}{2}$ min. respectively in the test group and with no treatment in the control group. Then, specimens were processed for scanning electron microscopic observation. 1. Both test and control group showed a few shallow grooves and ridges in pure titanium machined surface implants. There were not significant differences between two groups. 2. In the SLA surfaces, the control specimen showed that the macro roughness was achieved by large-grit sandblasting. Subsequently, the acid-etching process created the micro roughness, which thus was superimposed on the macro roughness. Irrespective of the application time of 50mg/ml TC-HCI solution, in general, test specimens were similar to control. 3. In the porous surfaces, the control specimen showed spherical particles of titanium alloy and its surface have a few shallow ridges. The roughness of surfaces conditioned with tetracycline-HCI was lessened and seen crater-like irregular surfaces relative to the application time. In conclusion, pure titanium machined surfaces and SLA surfaces weren't changed irrespective of the application time of tetracycline-HCI solution. But the porous surfaces conditioned with tetracycline-HCI solution began to be slightly changed from 2 min. This results are expected to be applied to the regenerative procedures for peri-implantitis treatment.

• Natural Product Sciences
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• v.11 no.1
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• pp.27-32
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• 2005

The purpose of this study is to evaluate the inhibitory effects of Resina Pini against Streptococcus mutans (S. mutans) that is one of the major causes of dental caries and oral diseases. Topically applied Resina Pini (RP) would be incorporated in saliva and thus the factor associated with water solubility should be considered. In this paper, therefore, effects of various treatment for RP and activities of water extracts from unprocessed and processed RP were compared. The crude RP (RP1) and the recrystallized RP (RP2) in ethanol solution showed strong antimicrobial activities (d.>15mm) against S. mutans. All RP samples exhibited considerable inhibitory effect against glucosyltransferase produced by S. mutans $(IC_{50}=91.2\;to\;276.2\;{\mu}g/ml)$. The very considerable increase in cellular permeability of S. mutans was observed with RP1, RP2 and their water extracts. These results suggest that RP1 and RP2 may be a potential source for pharmaceutical products used for prevention and/or treatment of dental caries and periodontal disease.

• Journal of Digital Convergence
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• v.12 no.4
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• pp.251-257
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• 2014

In u-Healthcare environment, large amounts of important vital information is processed through M2M(Machine to Machine). M2M is configured by wireless networks and has several problems for limited bandwidth and low reliability. Therefore, in this paper is proposed a method called uHLZW(u-Healthcare LZW) to improve channel efficiency to solve such problem. uHLZW algorithm has high compression ratio for vital data. The results showed that the average compression ratio of uHLZW got from 1.6 times to 4.0 times better than existing methods(Huffman and LZW compression).

• Bulletin of the Korean Chemical Society
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• v.33 no.5
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• pp.1653-1658
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• 2012

A new anthracene-containing conjugated molecule was synthesized through the Sonogashira coupling and reduction reactions. 1-Ethynyl-4-hexylbenzene was coupled to 2,6-bis((4-hexylphenyl) ethynyl)anthracene-9,10-dione through a reduction reaction to generate 2,6,9,10-tetrakis((4-hexylphenyl)ethynyl) anthracene. The semiconducting properties were evaluated in an organic thin film transistor (OTFT) and a single-crystal field-effect transistor (SC-FET). The OTFT showed a mobility of around 0.13 $cm^2\;V^{-1}\;s^{-1}$ ($I_{ON}/I_{OFF}$ > $10^6$), whereas the SC-FET showed a mobility of 1.00-1.35 $cm^2\;V^{-1}\;s^{-1}$, which is much higher than that of the OTFT. Owing to the high photoluminescence quantum yield of 2,6,9,10-tetrakis((4-hexylphenyl)ethynyl) anthracene, we could observe a significant increase in drain current under irradiation with visible light (${\lambda}$ = 538 nm, 12.5 ${\mu}W/cm^2$).