• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.434-434
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• 2012

Despite recent efforts for fabricating flexible transparent conducting films (TCFs) with low resistance and high transmittance, several obstacles to meet the requirement of flexible displays still remain. Indium tin oxide (ITO) thin films, which have been traditionally used as the TCFs, have a serious obstacle in TCFs applications. SWNTs are the most appropriate materials for conductive films for displays due to their excellent high mechanical strength and electrical conductivity. Recently, it has been demonstrated that acid treatment is an efficient method for surfactant removal. However, the treatment has been reported to destroy most SWNT. In this work, the fabrication by the spraying process of transparent SWNT films and reduction of its sheet resistance by Au-ionic doping treatment on PET substrates is researched. Arc-discharge SWNTs were dispersed in deionized water by adding sodium dodecyl sulfate (SDS) as surfactant and sonicated, followed by the centrifugation. The dispersed SWNT was spray-coated on PET substrate and dried on a hotplate. When the spray process was terminated, the TCF was immersed into deionized water to remove the surfactant and then it was dried on hotplate. The TCF film was then was doped with Au-ionic doping treatment, rinsed with deionized water and dried. The surface morphology of TCF was characterized by field emission scanning electron microscopy. The sheet resistance and optical transmission properties of the TCF were measured with a four-point probe method and a UV-visible spectrometry, respectively. This was confirmed and discussed on the XPS and UPS studies. We show that 87 ${\Omega}/{\Box}$ sheet resistances with 81% transmittance at the wavelength of 550 nm. The changes in electrical and optical conductivity of SWNT film before and after Au-ionic doping treatments were discussed. The effects of hole transport interface layer using Au-ionic doping SWNT on the performance of organic solar cells were investigated.

• Journal of the Korean Society of Clothing and Textiles
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• v.33 no.6
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• pp.980-989
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• 2009

Amur cork tree was extracted in methanol with the purpose of investigating the most effective extraction procedure for detecting the chromophore using the GC-MS analysis. Different procedures of waterbath and hotplate extractions were carried out and five different GC-MS instrument parameters including the operating temperatures in the GC capillary column and the MSD scan range were tested for their efficiencies. Berberine was determined by the detection of dihydroberberine at 15.0 min r.t. Hotplate was a better device for extracting amur cork tree than waterbath shaker either with or without presoaking in the room temperature. Water was not an adequate extraction medium for the berberine detection. The most effective GC-MS parameter was Method 4; the initial temperature at $50^{\circ}C$ followed by the temperature increase of $23^{\circ}C$/min until $210^{\circ}C$, then increase of $30^{\circ}C$/min until the final temperature reach at $305^{\circ}C$, then hold for 14 minutes to maintain the total run time 24.12 minutes. The MSD scan range for Method 4 was $35\sim400$m/z.

• Analytical Science and Technology
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• v.15 no.4
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• pp.381-387
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• 2002

In this study, we introduced experience participated in ELPAT (Environmental Lead for Proficiency Analytical Testing) program that is administered by the American Industrial Hygiene Association and EPA. The 126 sample results of total 128 samples met reference value, as a result accepted 'proficient'. The concentration of Pb in air, paint chips, soils and dust wipes are $0.0089{\sim}0.3956mg/m^3$, 0.0500~8.9149%, 29.0${\sim}$1697 mg/kg and $18.00{\sim}900.3{\mu}g/sample$, respectively. The lead in environmental matrix prepared adequate techniques and analysed by flame atomic absorption spectrometry. The lead in air was extracted hydrochloric acid, in paint chips and soils were digested with microwave and hotplate and in dust wipes were prepared microwave digestion. No differences of each preparation techniques was found and all methods were to be proper.

• Korean Journal of Pharmacognosy
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• v.51 no.3
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• pp.186-191
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• 2020

In this study, we evaluated the anti-nociceptive activities of Sorbus alnifolia. To investigate the anti-nociceptive properties of the methanolic extract of Sorbus alnifolia (MSA), we conducted several tests using various experimental mouse pain models. Herein, MSA significantly delayed the latency time and writhing motion in the hotplate test and acetic acid test, respectively. These result indicated that MSA has an ability to manage both peripheral and central nociception. We could further confirm the analgesic effects of MSA by performing formalin test. In combination test using naloxone, a non-selective opioid receptor antagonist, analgesic activity of MSA was partly antagonized by naloxone, but not completely, indicating that the MSA acts as a partial opioid receptor agonist. Out results suggest that the S. alnifolia may be possibly used as valuable anti-nociceptive agent.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.380-381
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• 2012

Bioinspired sea urchin-like structures were fabricated on silicon by inductively coupled plasma (ICP) etching using lens-like shape hexagonally patterned photoresist (PR) patterns and subsequent metal-assisted chemical etching (MaCE) [1]. The lens-like shape PR patterns with a diameter of 2 ${\mu}m$ were formed by conventional lithography method followed by thermal reflow process of PR patterns on a hotplate at $170^{\circ}C$ for 40 s. ICP etching process was carried out in an SF6 plasma ambient using an optimum etching conditions such as radio-frequency power of 50 W, ICP power of 25 W, SF6 flow rate of 30 sccm, process pressure of 10 mTorr, and etching time of 150 s in order to produce micron structure with tapered etch profile. 15 nm thick Ag film was evaporated on the samples using e-beam evaporator with a deposition rate of 0.05 nm/s. To form Ag nanoparticles (NPs), the samples were thermally treated (thermally dewetted) in a rapid thermal annealing system at $500^{\circ}C$ for 1 min in a nitrogen environment. The Ag thickness and thermal dewetting conditions were carefully chosen to obtain isolated Ag NPs. To fabricate needle-like nanostructures on both the micron structure (i.e., sea urchin-like structures) and flat surface of silicon, MaCE process, which is based on the strong catalytic activity of metal, was performed in a chemical etchant (HNO3: HF: H2O = 4: 1: 20) using Ag NPs at room temperature for 1 min. Finally, the residual Ag NPs were removed by immersion in a HNO3 solution. The fabricated structures after each process steps are shown in figure 1. It is well-known that the hierarchical micro- and nanostructures have efficient light harvesting properties [2-3]. Therefore, this fabrication technique for production of sea urchin-like structures is applicable to improve the performance of light harvesting devices.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.316-316
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• 2010

Thin films spin-coated from solvent solutions are characterized by solution parameters and spin-coating process. In this study, performance characteristics of polymer solar cells were investigated with changing solution parameters such as solvent and additives. The phase-separation between polymer and fullerene is needed to make the percolation pathway for better transportation of hole and electron in polymer solar cells. For this reason, cooperative effects of solvent mixtures adding additives with distinct solubility have been studied recently. In this study, chlorobezene, 1, 2-dichlorbenzene, and chloroform were used as solvent. 1, 8-diiodoctaned and 1, 8-octanedithiol were used as additives and were added into poly(3-hexylthiophene-2, 5-diyl)/[6, 6]-phenyl C61 butyric acid methyl ester (P3HT/PCBM) blends. Pre-patterned ITO glass was cleaned using ultrasonication in mixed solvent with ethyl alcohol, isopropyl alcohol and acetone. PEDOT:PSS was spin-coated on to the ITO substrate at 3000rpm and was baked at $120^{\circ}C$ for 10min on the hotplate. The prepared solution was spin-coated at 1000rpm and the spin-coated thin film was dried in the Petri dishes. Al electrode was deposited on the thin film by thermal evaporation. The devices were annealed at $120^{\circ}C$ for 30min. By adding 2.5 volume percent of additives into the chlorobenzene from that bulk heterojunction films consisting of P3HT/PCBM, the power efficiency (AM 1.5G conditions) was increased from 2.16% to 2.69% and 3.12% respectively. We have investigated the effect of additives in P3HT/PCBM blends and the film characteristics and the film characteristics including J-V characteristics, absorption, photoluminescence, X-ray diffraction, and atomic force microscopy to mainly depict the morphology control by doping additives.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.341-341
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• 2012

Recently, oxide semi-conductor materials have been investigated as promising candidates replacing a-Si:H and poly-Si semiconductor because they have some advantages of a room-temperature process, low-cost, high performance and various applications in flexible and transparent electronics. Particularly, amorphous indium-gallium-zinc-oxide (a-IGZO) is an interesting semiconductor material for use in flexible thin film transistor (TFT) fabrication due to the high carrier mobility and low deposition temperatures. In this work, we demonstrated improvement of flexibility in IGZO TFTs, which were fabricated on polyimide (PI) substrate. At first, a thin poly-4vinyl phenol (PVP) layer was spin coated on PI substrate for making a smooth surface up to 0.3 nm, which was required to form high quality active layer. Then, Ni gate electrode of 100 nm was deposited on the bare PVP layer by e-beam evaporator using a shadow mask. The PVP and $Al_2O_3$ layers with different thicknesses were used for organic/inorganic multi gate dielectric, which were formed by spin coater and atomic layer deposition (ALD), respectively, at $200^{\circ}C$. 70 nm IGZO semiconductor layer and 70 nm Al source/drain electrodes were respectively deposited by RF magnetron sputter and thermal evaporator using shadow masks. Then, IGZO layer was annealed on a hotplate at $200^{\circ}C$ for 1 hour. Standard electrical characteristics of transistors were measured by a semiconductor parameter analyzer at room temperature in the dark and performance of devices then was also evaluated under static and dynamic mechanical deformation. The IGZO TFTs incorporating hybrid gate dielectrics showed a high flexibility compared to the device with single structural gate dielectrics. The effects of mechanical deformation on the TFT characteristics will be discussed in detail.

• The Korean Journal of Pain
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• v.33 no.1
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• pp.13-22
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• 2020

Background: The continuous search for a novel neuropathic pain drug with few or no side effects has been a main focus of researchers for decades. This study investigated the antinociceptive and neuroprotective effects of bromelain in sciatic nerve ligation-induced neuropathic pain in Wistar rats. Methods: Forty-eight Wistar rats randomly divided into eight groups comprised of six animals each were used for this study. Peripheral neuropathy was induced via chronic constriction of the common sciatic nerve. Thermal hyperalgesic and mechanical allodynia were assessed using a hotplate and von Frey filaments, respectively. The functional recovery and structural architecture of the ligated sciatic nerve were evaluated using the sciatic functional index test and a histological examination of the transverse section of the sciatic nerve. The neuroprotective effects of bromelain were investigated in the proximal sciatic nerve tissue after 21 days of treatment. Results: Bromelain significantly (P < 0.05) attenuated both the thermal hyperalgesia and mechanical allodynic indices of neuropathic pain. There were improvements in sciatic function and structural integrity in rats treated with bromelain. These rats showed significant (P < 0.05) increases in sciatic nerve nuclear transcription factors (nuclear factor erythroid-derived-2-related factors-1 [NrF-1] and NrF-2), antioxidant enzymes (superoxide dismutase and glutathione), and reduced membranelipid peroxidation compared with the ligated control group. Conclusions: This study suggest that bromelain mitigated neuropathic pain by enhancing the activities of nuclear transcription factors (NrF-1 and NrF-2) which increases the antioxidant defense system that abolish neuronal stress and structural disorganization.

• Journal of Sensor Science and Technology
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• v.5 no.5
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• pp.69-77
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• 1996

In this paper, we fabricated the micro hotplate which consisted of a thin film heater(Pt/Cr bilayers) sandwiched with the thermal oxide and E-beam evaporated oxide. And we studied the electrical and the structural properties of Pt/Cr bilayers due to annealing temperature. When we compared the temperature measured from type k thermocouples with the temperature acquired from I.R. thermo-vision system according to the variations of emissivity, the emissivity of I-beam evaporated oxide was 0.5. The sheet resistance of Pt/Cr bilayers didn't depend on the Cr layer thickness, and it was considered as the existence of CrO between the Pt and the Cr layer. When the annealing temperature was increased from $500^{\circ}C$ to $700^{\circ}C$, the out-diffusions of Cr were increased(which was confirmed by AES depth profile) and the grain size of Pt(220) phase was enlarged also(analyzed by XRD and SEM photographs). From the results of XRD analysis and AES depth profile, the Pt/Cr bilayers annealed at $500^{\circ}C$ were more stable than any other cases in structural properties.

• The Korean Journal of Pain
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• v.34 no.1
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• pp.47-57
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• 2021

Background: Lumbar disc herniation (LDH) is a common cause of radicular pain, but the mechanism is not clear. In this study, we investigated the engagement of toll-like receptor 4 (TLR4) and the nuclear factor-kappa B (NF-κB) in radicular pain and its possible mechanisms. Methods: An LDH model was induced by autologous nucleus pulposus (NP) implantation, which was obtained from coccygeal vertebra, then relocated in the lumbar 4/5 spinal nerve roots of rats. Mechanical and thermal pain behaviors were assessed by using von Frey filaments and hotplate test respectively. The protein level of TLR4 and phosphorylated-p65 (p-p65) was evaluated by western blotting analysis and immunofluorescence staining. Spinal microglia activation was evaluated by immunofluorescence staining of specific relevant markers. The expression of proand anti-inflammatory cytokines in the spinal dorsal horn was measured by enzyme linked immunosorbent assay. Results: Spinal expression of TLR4 and p-NF-κB (p-p65) was significantly increased after NP implantation, lasting up to 14 days. TLR4 was mainly expressed in spinal microglia, but not astrocytes or neurons. TLR4 antagonist TAK242 decreased spinal expression of p-p65. TAK242 or NF-κB inhibitor pyrrolidinedithiocarbamic acid alleviated mechanical and thermal pain behaviors, inhibited spinal microglia activation, moderated spinal inflammatory response manifested by decreasing interleukin (IL)-1β, IL-6, tumor necrosis factor-α expression and increasing IL-10 expression in the spinal dorsal horn. Conclusions: The study revealed that TLR4/NF-κB pathway participated in radicular pain by encouraging spinal microglia activation and inflammatory response.