• 전기전자학회논문지
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• 제26권4호
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• pp.705-709
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• 2022

Poly(vinylidene fluoride-trifluoroethylene)(P(VDF-TrFE)) 고체 전해질 층의 어닐링 온도가 고분자 멤리스터의 전기적 특성에 미치는 영향을 분석하였다. 형태적 분석에서 100℃ 어닐링 온도를 갖는 P(VDF-TrFE) (100P(VDF-TrFE)) 박막 대비 200℃ 어닐링 온도를 갖는 P(VDF-TrFE) (200P(VDF-TrFE)) 박막의 표면 거칠기가 약 5배 크고 두께는 약 20% 작은 것으로 나타났다. 100P(VDF-TrFE)를 갖는 멤리스터 (M100) 대비 200P(VDF-TrFE) 멤리스터 (M200)의 set voltage는 약 50% 감소하였고, reset voltage의 크기는 약 30% 증가하였다. 또한, M200이 M100보다 더 나은 메모리 유지 특성을 갖는 것으로 나타났다. 이러한 차이는 M100 대비 M200 내부의 강한 국소 전기장 때문인 것으로 판단된다. 본 연구는 고분자 멤리스터의 어닐링 온도의 중요성을 제시함에 의의가 있다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2010년도 춘계학술발표대회
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• pp.30.2-30.2
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• 2010

Nano-scale p-n junction can generate various nano-scale functional devices such as nanowire light emitting diode, nanowire solar cell, and nanowire sensor. The core shell type nanowire p-n junction has been considered for the high efficient devices in many previous reports. On the other hand, although device efficiency is relatively lower, the cross bar type p-n junction has simple topological structure, suggested by C.M. Lieber group, to integrate easily many p-n junction devices in one board. In this study, for the integration of the cross bar nanowire p-n junction device, a simple fabrication route, employed dielectrophoretic array and direct printing techniques, was demonstrated by the successful fabrication and programmable integration of the nanowire cross bar p-n junction solar cell. This direct printing process will give the single nanowire solar cell the opportunity of the integration on the circuit board with other nanowire functional devices.

• 한국표면공학회지
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• 제19권4호
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• pp.140-148
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• 1986

Using sodium pyrophoshate as complexing agent, the characteristics and the magnetic properties of the films deposited from electroless cobalt plating bath have been studied. The result obtained are as following; 1. It was found that the optimum bath compositions consisted of 0.1M cobalt sulfate, 0.2M sodium hypophosphite as reducing agent, 0.4M sodium pyrophosphate as complexing agent and 0.5M ammonium sulfate as buffer agent, whereas good operating conditions were the bath of pH 10.5 adjusted with ammonia and 70$^{\circ}C$ of bath temperature, respectively. 2. The coercive force and the squareness of magnetic films were increased with deposition from the low temperature bath. 3. The phosphorous content in Co-P films deposited from these bath was relatively higher than that from Brenner bath. It was assumed to be due to codeposition of phosphorous from the pyrophosphate anion in the solution.

• 대한의용생체공학회:의공학회지
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• 제17권3호
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• pp.291-296
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• 1996

Poly(ethylene glycol)(PEG) macromers terminated with diacrylate Iyoups and interpenetrating poly- mer networks(IPN) composed of poly(hydroxyethyl methacrylate)(PHEMA) or poly(hydroxyethyl methacrylate-co-hydronypropyl methacrylate-co- N-vinyl pyrrolidone ) [ P( HEM A-co- HPM A-co- NVP) ] and PEG macromer were synthesized with the aim of obtaining protein adsorption resistant soft contact lens. Polymerization of PEC macromer resulted in the formation of cross-linked gels due to the multifunctionality of macromer. Crosslinked P(HEMA) or P(HEMA-co-HPMA-co-WVP) chains were interpenetrated into the cross-linked three-dimensional networks of PEG. It was found that albumin adsorption onto the contact lens prepared by P(HEMA-co-HPMA-co-NVP) /PEG IPW decreases with an increase of molecular weight of PEG. Also, it was found that albumin adsorption onto the both contact lens decreases with an increase of concentration of PEC macromer in the IPN preparation. There are also more adequate in the bioinertnen for the contact lens by P(HEMA)/PEG IPN or P (HEMA-co-HPMA-co-NVP)/PEG IPN than that by P(HEMA) or P(HEMA-co-HPMA-co-NVP)

• 한국표면공학회지
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• 제34권5호
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• pp.475-480
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• 2001

Diffusion of Cu into the low-k para-xylene based plasma polymer (pXPP) thin films deposited by plasma-enhanced chemical vapor deposition using the para-xylene precursor was comparatively measured using various methods. Cu layer was deposited on the surfaces of pXPPs treated by $N_2$ plasma generated in a magnetically enhanced inductively coupled plasma reactor. Diffusion characteristics of Cu into pXPPs were measured using Rutherford backscattering spectroscopy (RBS), secondary ion mass spectroscopy (SIMS), cross-sectional transmission electron microscopy (XTEM), and current-voltage (I-V) measurements for the vacuum-annealed Cu/pXPPs for 1 hour at $450^{\circ}C$ and were compared. The results showed a correlation between the I-V measurement and SIMS data are correlated and have a sensitivity enough to evaluate the dielectric properties but the RBS or XTEM measurements are not sufficient to conclude the electrical properties of low-k dielectrics with Cu in the film bulk. The additional results indicate that the pXPP layers are quite resistant to Cu diffusion at the annealing temperature of $450^{\circ}C$ compared to the other previously reported organic low-k materials.

• Journal of Microbiology and Biotechnology
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• 제17권5호
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• pp.769-773
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• 2007

With the aim to produce ascorbic acid-2-phosphate(AsA-2-P) from L-ascorbic acid(AsA, Vitamin C), nine bacteria conferring the ability to transform AsA to AsA-2-P were isolated from soil samples alongside known strains from culture collections. Most isolates were classified to the genus Brevundimonas by 16S phylogenetic analysis. Among them, Brevundimonas diminuta KACC 10306 was selected as the experimental strain because of its the highest productivity of AsA-2-P. The optimum set of conditions for the AsA-2-P production from AsA using resting cells as the source of the enzyme was also investigated. The optimum cultivation time was 16 h and the cell concentration was 120g/l(wet weight). The optimum concentrations of AsA and pyrophosphate were 550mM and 450mM, respectively. The most effective buffer was 50mM sodium formate. The optimum pH was 4.5 and temperature was $40^{\circ}C$. Under the above conditions, 27.5g/l of AsA-2-P was produced from AsA after 36 h of incubation, which corresponded to a 19.7% conversion efficiency based on the initial concentration of AsA.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XII)
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• pp.403-408
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• 2003

A newly isolated Rhodopseudomonas palustris P4 could decolorize various synthetic dyes containing different chromogenic groups such as azo linkage (Crocein Orange G, New Coccine, Chromotrope FB, Congo Red, Remazol Black B), anthraquinone Reactive blue 2, or indigo Indigo Carmine. Among them, the degradation rate of Black B was studied in detial. Degradation of Black B followed the Arrhenius equation in 25 - $40^{\circ}C$ with an activation energy of 7.79 kcal/mol. Optimum pH was 8. Glucose in the range of 5 - 50g/l did not affect the Black B decolorization. When Black B increased from 25 mg/l to 2000 mg/l, decolorization activity increased almost linearly but the extent of decolorization was constant at about 86% irrespective of dye concentration. Analyses by HPLC revealed that the Black B molecules were partially degraded and some chromogenic intermediates were produced. These results indicate that Rps. palustris P4 has an outstanding capability to degrade various dyes.

• Asian Pacific Journal of Cancer Prevention
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• 제16권8호
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• pp.3493-3498
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• 2015

Objective: To assess associations between codon 72 polymorphisms (Pro or B and Arg or b alleles) of the TP53 gene and lung cancer risk among Bangladeshis. Materials and Methods: The distribution of the BB, Bb, and bb genotypes and the frequencies of the B and b alleles were determined by PCR-RFLP method using DNA extracted from leucocytes of 50 confirmed lung cancer patients and 50 age-matched controls and the data were analysed. Results: The ratio of BB, Bb, and bb genotypes were in Hardy-Weinberg equilibrium except for the male patients (${\chi}2=4.6$). The B allele is overrepresented among all patients (OR=2.0, p=0.02) and the female patients (OR=4.1, $p{\leq}0.01$) compared to the controls. The BB/bb ratio was also higher among the patients (OR=3.0, p=0.03). The relative risk of cancer for having BB over bb genotype was 1.8 (p=0.04) but no effect was observed for the Bb genotype. The B allele was overrepresented among patients with adenocarcinomas (OR=2.4, $p{\leq}0.01$) and squamous cell carcinomas (OR=2.7, $p{\leq}0.01$) over the controls but the difference was not significant for those with small cell lung carcinomas (OR=1.1, p=0.66). The B allele was overrepresented among patients age 50 or younger (OR=2.7, $p{\leq}0.01$), but not for older patients (OR=1.7, p=0.07), and among smokers compared to the controls (OR=1.8-10.0, $p{\leq}0.01-0.03$). However, no correlation between increasing pack-years and lung cancer was observed. Conclusions: The Pro/Pro (BB) genotype and the B allele are risk factors for lung cancer among Bangladeshis, particularly for people under age 50, women and smokers.

• Journal of Applied Biological Chemistry
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• 제56권3호
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• pp.171-177
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• 2013

Efficient extraction of total proteins from soil microorganisms is tedious because of small quantity. In this regard, an improved method for extraction of whole cell proteins is developed from soil microorganisms, Saccharomyces cerevisiae and Pichia pastoris. of which the cell wall are very strong. Pretreatment with NH4OH prior to the final extraction using NaOH/SDS was tried under the basis that ammonium ion was possible to enhance the permeability and/or to weaken the yeast cell walls. The pre-treatment of yeast cells with NH4OH drastically enhanced the protein extraction when it was compared with control (without NH4OH pre-treatment). At the pre-treatment of 0.04 N NH4OH at pH 9.0, about 3 fold of proteins was obtained from p. pastoris. Ammonium hydroxide appears to penetrate into the yeast cell walls more readily at basic pH. The effect of NH4OH pretreatment was pH dependent. The methods developed in this experiment might be applicable for an effective extraction of yeast proteins for the purpose of biochemical studies, especially proteomic analysis.

• Environmental Engineering Research
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• 제13권1호
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• pp.8-13
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• 2008

The extent of solubility enhancement by biosurfactant was examined at various pHs prior to the biodegradation experiments. The molar solubilization ratio (MSR) was calculated from the batch solubilization experiments and the highest MSR was detected at pH 5. The effect of the biosurfactant, rhamnolipids, on the phenanthrene mineralization in soil-water system was investigated. The strain 3Y was selected for the mineralization assay and large amounts of phenanthrene were degraded at neutral pH in soil-water system without the biosurfactant. The addition of 150 mg/L rhamnolipids showed no effect on mineralization of phenanthrene in soil-water system, and total mineralization rates after 6 weeks incubation at each pH showed no differences in presence and absence of rhamnolipids. Our result indicated that the toxic effect of rhamnolipids can disappear when soil particles exist, and also the enhanced solubility of phenanthrene does not work for mineralization enhancement in this soil-water system.