• 한국재료학회지
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• 제15권6호
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• pp.361-369
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• 2005

InP(100) crystal surface was irradiated by ion beams with low energy $(180\~225\;eV)$ and high flux $(\~10^{15}/cm^2/s)$, Self-organization process induced by ion beam was investigated by examining nano structures formed during ion beam sputtering. As an ion source, an electrostatic closed electron Hall drift thruster with a broad beam size was used. While the incident angle $(\theta)$, ion flux (J), and ion fluence $(\phi)$ were changed and InP crystal was rotated, cone-like, ripple, and anistropic nanostrucuture formed on the surface were analyzed by an atomic force microscope. The wavelength of the ripple is about 40 nm smaller than ever reported values and depends on the ion flux as $\lambda{\propto}J^{-1/2}$, which is coincident with the B-H model. As the incident angle is varied, the root mean square of the surface roughness slightly increases up to the critical angle but suddenly decreases due to the decrease of sputtering yield. By the rotation of the sample, the formation of nano dots with the size of $95\~260\;nm$ is clearly observed.

• 한국정보통신학회논문지
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• 제15권10호
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• pp.2217-2222
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• 2011

본 연구에서는 이중게이트(Double Gate; DG)MOSFET의 채널내 전위와 전하분포의 관계를 가우스 함수를 이용한 포아송방정식으로부터 유도하고자 한다. 즉, 도핑분포는 가우스 함수를 이용하였으며 변수인 이온주입범위 및 분포편차에 대하여 문턱전압이하 스윙과 산화막 두께의 관계를 관찰하고자 한다. 포아송방정식으로부터 해석학적 전위분포 모델을 구하였으며 이를 이용하여 산화막 두께에 대한 문턱전압이하 스윙값의 변화를 구하였다. 문턱전압이하 스윙은 게이트전압에 대한 드레인전류의 변화를 나타내고 이론적으론 최소값 60 mV/dec을 나타내며 디지털소자응용에 매우 중요한 요소이다. 본 연구의 모델이 타당하다는 것을 입증하기 위하여 포텐셜 분포값을 수치해석학적 값과 비교하였다. 결과적으로 본 연구에서 제시한 포텐셜모델이 수치해석학적 시뮬레이션모델과 매우 잘 일치하였으며 도핑분포에 따라 문턱전압이하 스윙과 산화막두께의 관계를 분석하였다.

• 한국표면공학회지
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• 제53권3호
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• pp.116-123
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• 2020

Ion beam irradiation induces self-organization of nanostructure on the surface of polymer film. We show that the incident angle of Ar ions on polyethylene naphthalate(PEN) film changes self-organized nanostructure. PEN film was irradiated by argon ion beams with the ion incident angle of 0°, 30°, 45°, 60°, and 80°. Nanostructure was altered from dimple to ripple structure as the angle increases. The ripple structure changed to pillar structure after 60°due to that the shallow incident angle increased the ion energy transfer per depth up to 50 eV/Å, which value could induce excessive surface heating and oligomer formation reacting as a physical mask for anisotropic etching. And quantitative analysis of the nanostructures was adapted by using ABC model and fractal dimension theory.

• 한국축산식품학회지
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• 제40권6호
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• pp.1055-1065
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• 2020

This study investigated the effects of brine injection and high hydrostatic pressure (HHP) on the quality characteristics of pork loin. Brine with ionic strength conditions (0.7% vs 1.5% NaCl, w/v) were injected into pork loins, and the meat was pressurized up to 500 MPa for 3 min. As a quality indicator, moisture content, color, cooking loss and texture profile analysis (TPA) of pork loins were estimated. Based on the results, brine with low ionic strength (0.7% NaCl) resulted in low injection efficiency and high cooking loss, although, it improved tenderness of pork loin at moderate pressure level (~200 MPa). While high ionic strength condition (1.5% NaCl injection) lowered the hardness of pork loins at relatively high HHP level (400-500 MPa), it also caused high cooking loss. To commercialize the brine injected pork loins, it was necessary to regulate brine compositions, which was not evaluated in this study. Nevertheless, the present study demonstrated that brine injection followed by moderate pressure (200 MPa) could improve the tenderness of pork loins without causing other major quality losses.

• 한국식품저장유통학회지
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• 제11권2호
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• pp.207-213
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• 2004

다양한 기능성을 갖는 생약재 32종을 대상으로 천연보존료 개발의 일환으로 메탄올로 추출한 항균활성 물질을 몇 종의 병원균과 식중독균, 식품과 관련이 있는 세균, 젖산균 및 효모 등 12종의 균주 B. subtilis, M. luteus, Sta aureus, Sta. epidermidis, Strep. mutans, E. coli, Pse. aeruginosa, Sal. typhimurium, V. vulnificus, Lac. brevis, Leu. mesenteroides, Sacch. cerevisiae에 대하여 항균활성을 검색하였으며, 항균력이 강한 생약재 추출물은 최소저해농도(MIC)를 측정하였다. 검색한 결과 계피, 목단, 적양, 정향, 팔각향 등의 메탄올 추출물은 12균주 중 세균에 대하여 항균활성이 강하였으나, 젖산균 및 효모에 대해서는 낮은 항균활성을 보였다. 최소저해농도는 B. subtilis에 대해 강한 증식억제효과를 보였고, Sta. epidermidis나 Pse. aeruginosa에 대해서도 거의 모든 추출물이 저해활성을 나타내었다. 하지만 항균활성 측정시 거의 저해가 없었던 Lue. mesenteroides도 대부분의 추출물에서 억제 효과를 나타내 항균성과는 약간 다른 결과를 보였다. 생약재 중 강한 항균력을 보인 녹차, 정향, 적양, 인진호 등은 폴리페놀 함량이 약 7 mg/g 이상으로 높아 이들 페놀성 물질들이 항균활성에 많은 영향을 준 것으로 사료된다. 따라서 여러 미생물에 의해 변패될 수 있는 식품에서 천연보존료로의 이용이 가능할 것으로 생각된다.

• 한국재료학회지
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• 제15권8호
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• pp.491-495
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• 2005

(Zn,Mg)O (ZMO) thin films doped with Ga $(0\~0.03mol\%)$ in the target source were prepared by pulsed laser deposition on c-plane sapphire substrates at $500^{\circ}C$, and the effect of Ga contents on the properties of the electrical, optical and crystal properties of the deposited films was investigated. From X-ray diffraction patterns, ZMO film doped with $0.02 mol\%$ Ga showed crystal structure with c-axis preferred orientation, showing only the (0002) and (0004) diffraction peaks. In contrast, ZMO film doped with $Ga=0.03 mol\%$ showed a randomly oriented crystal structure. All the samples were highly transparent, showing the transmittance values of above $85\%$ in the visible region. For all the Ga doped ZMO films, the value of energy band gap was found to be about 3.5 eV, regardless of their Ga contents. From the Hall measurements, the resistivity and the carrier density for the ZMO film doped with $0.01 mol\%$ Ga were about $5\times10^{-4}\Omega-cm$ and $2\times10^{21}cm^{-3}$, respectively.

• Radiation Oncology Journal
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• 제13권2호
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• pp.121-128
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• 1995

Purpose: The enhanced cytotoxic effect of combined treatment of hyper-thermia and chemotherapy by increasing intracellular acidity with HMA was investigated. Materials and Methods: FSall tumor cells were injected on the hindlegs of female $C_3H$ mice. When the tumor volume reached about 200mm3, experiments were performed on the groups classified as follows: Group I :Control, Group II : Melphalan alone (2.5mg/kg, 5mg/kg, 10mg/kg, 15mg/kg), Group III : Heat alone $(42.5^{\cdot}C$ for 1 hour) Group IV : Melphalan + Heat $(42.5^{\cdot}C$ for 1 hour), Group V : HMA(10mg/kg) + Melphalan(5.0mg/kg) + Heat$(42.5^{\cdot}C$ for 1hour). Each group included 8-12 mice on each experiment HMA (3-amino-6-chloro-5-(1-homopiperidyl )-N-(diaminomethylene) -c-pyrazinecarboxamide), an analog of amiloride which increases intracellular pH(pHi) was dissolved in dimethyl sulfoxide (DMS) and injected into the tumor-bearing mice through the tail vein. 10mg/kg of HMA and each dose of melphalan were injected into peritoneum of the tumor-bearing mice 30 minutes before heating. Tumor growth delay was calculated when the tumor volme reached at $1500mm^3$ Excision assay was performed on each group and repeated 2-4 times. Results : Tumor growth delay of each experimental groups at $1500mm^3$ were 9, 10, 13 and 19 days respectively. In vivo-in vitro excision assay using FSall tumor cells, the cytotoxicity of each experimental groups was $1.2{\times}10^7,\;1{\times}10^7,\;6{\times}10^6,\;1.7{\times}10^6\;and\;1{\times}10^5$ clonogenic cells/gm respectively When HMA was added to the combined treatment of heat and .chemotherapy, the tumor growth was delayed more than combined treatment without HMA i.e., 6 days tumor growth delay at $1500mm^3$ of tumor volume. Conclusion: The combined effect of cytotoxicity by heat and chemotherapy can be much more enhanced by HMA.

• 상하수도학회지
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• 제30권5호
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• pp.501-509
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• 2016

In this study, a flat-type photocatalytic reactor is applied under solar irradiation for simultaneous treatment of target pollutants: reduction of Cr(VI) to Cr(III) and oxidation of EDCs (BPA, EE2, E2). An immobilized type of photocatalyst was fabricated to have self-grown nanotubes on its surface in order to overcome limitations of powdery photocatalyst. Moreover, Ti mesh form was chosen as substrate and modified to have both larger surface area and photocatalyst content. Ti mesh was anodized at 50V and $25^{\circ}C$ for 30min in the mixed electrolytes ($NH_4F-H_2O-C_2H_6O_2$) and annealed at $450^{\circ}C$ for 2 hours in ambient oxygen to have anatase structure. Surface characterization was done with SEM and XRD methodologies. Fabricated NTT was applied to water treatment, and coexisting Cr(VI) and organics (EDCs) enhanced each other's reactions by scavenging holes and electrons and thus impeding recombination. Also, several experiments were conducted outdoor under direct sunlight and it was observed that both solar-tracking and applying modified photocatalyst were proven to enhance reaction efficiency.

• The Korean Journal of Physiology
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• 제19권2호
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• pp.101-111
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• 1985

Transient inward current (TI) was studied by the two micro-electrode voltage clamp technique in the sinoatrial node of the rabbit. The author confirmed that in $10^{-6}$ M ouabain TI was found in the SA node and investigated the effects of ions, $(Na^+,\;K^+,\;Ca^{2+})$, $\beta-agonist$ (isoprenaline), local anesthetics (quinidine, lidocaine) and Ca-blockers ($Co^{2+}$, verapamil, diltiazem) on the TI recorded during depolarizing voltage clamp pulses to -40 and -20 mV. The results obtained were as follows ; 1) $10^{-6}M$ ouabain increased the frequency of sinus action potential and decreased the amplitude, especially overshoot of action potential. TI was induced by the depolarizing voltage clamp Pulses and the magnitude of the slow inward current (isi) decreased and the time course was slowed by the same depolarizing pulses. 2) 30% $Na^{+}$ and 24mM $K^+$ decreased by $10^{-6}M$ ouabain and 6 mM $Ca^{2+}$ and $10^{-7}M$ isoprenaline increased TI, $i_{si}$ and current oscillations. 3) Quinidine $(5\times10^{-7}M)$ reduced TI and $i_{si}$ but lidocaine $(10^6\;-10^5M)$ didn't reduced or increase TI. Current oscillations increased and isi decreased by lidocaine. 4) Ca-blockers decreased the amplitude and the frequency of sinus action potential. TI and $i_{si}$ decreased significantly but were not abolished completely at the concentrations used in this experiment. Verapamil and diltiazem had inhibitory action on TI in $2\times10^{-7}M$ concentration and showed very slow recovery after wasting out with normal Tyrode solution.

• 동아시아식생활학회지
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• 제9권4호
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• pp.442-451
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• 1999

본 연구는 매실을 천연 항균물질로서의 이용 가능성을 검색하였다. 먼저 매실을 물과 methanol로 추출한 extracts를 paper disc법으로 항균활성을 확인한 후 MeOH extract를 용매별로 분획한 각각의 fractions으로 paper disc법과 그 결과를 토대로 활성이 높은 fractions을 비탁법을 이용하여 농도별로 액체 배지상에서 저해활성을 확인하였다. 변패균인 M leteus는 매실의 EtOAc 획분과 BuOH 획분에 의해서 저해되었고 또한 $H_2O$ 획분과 CHCㅣ$_3$ 획분도 저해활성을 보였다. 한편 저해농도 시템에서는 BuOH 획분 100ppm 첨가 시 전혀 생육을 하지 못했다. 매실의 EtOAc 획분과 BuOH 획분은 B. cereus, B. subtilis와 S. epidrimidis에 대해서 강한 저해 활성을 보였다. 저해농도 시험에서는 B. cereus는 BuOH 획분 100ppm, cB. subtilis는 EtOAc 획분 100ppm, S. epidrimidis는 EtOAc 획분 100ppm에서 생육을 하지 못했다. G(-)세균은 매실성분에 의해서 저해를 받지만 G(+)세균에 비하여 저항성이 켰다. E. coli는 EtOAc 획분 500ppm에서 미약한 生育을 하였으며 S. typhimurium는 EtOAc 획분, BuOH 획분 모두 1,000ppm에서 생육을 전혀 하지 못했으며 P. vulgaris는 BuOH 획분 100ppm, V. parahaemolyticus는 BuOH 획분, EtOAc 획분 100ppm에서 전혀 생육을 하지 못하는 결과를 얻었다. 한편, 효모중 S. cerevisiae IF01950은 EtOAc 획분 500ppm에서 50%의 저해를 받았으며 S. cerevisiae ATCC4105는 1,000ppm의 EtOAc fr. 에서 50%의 저해를 하였다. 항곰팡이 실험에서는 A. niger에서만이 아주 미약한 저해를 보였다.