• 한국재료학회지
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• 제10권1호
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• pp.7-14
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• 2000

본 연구는 무금속프탈로시아닌 색소계를 이용한 전자사진 감광체의 개발에 관한 것이다. 전하발생물질로서는 각종 형태의 무금속프탈로시아닌을 사용했고, 결합제로서는 각종 폴리머를 사용했으며, 전하이동물질로서는 히드라존유도체나 아연착화합물을 사용했다. 전하발생물질로서 사용한 ${\alpha}-$, ${\beta}-$, x형의 프탈로시아닌중에서는 x형의 무금속프탈로시아닌($x-H_2Pc$)의 경우가 가장 좋은 감도를 보였다. 전하발생물질로서는 $x-H_2Pc$를, 전하수송물질로서는 히드라존유도체를 사용했을 때, 다른 감광체들과 비교하여 73.1%의 높은 $1.50lux{\cdot}sec$의 좋은 감도를 보였다.

• EDISON SW 활용 경진대회 논문집
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• 제5회(2016년)
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• pp.163-166
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• 2016

Hydrophobicity is the key concept to understand the water plays in protein folding, protein aggregation, and protein-protein interaction. Traditionally, the hydrophobicity of protein is defined based on the scales of the hydrophobicity of residue, assuming that the hydrophobicity of free amino acids is maintained. Here, we explore how the hydrophobicity of constituting amino acids in protein rely on the protein context, in particular, on the total charge and secondary structures of a protein. To this end, we calculate and investigate the hydration free energy of three short proteins based on the integral-equation theory of liquids. We find that the hydration free energy of charged amino acids is significantly affected by the protein total charge and exhibits contrasting behavior depending on the protein total charge being positive or negative. We also observe that amino acids in the ${\beta}-sheets$ display more enhanced the hydrophobicity than amino acids in the loop, whereas those in the ${\alpha}-helix$ do not clearly show such a tendency. And the salt-bridge forming amino acids also exhibit increase of the hydrophobicity than that with no salt bridge. Our results provide novel insights into the hydrophobicity of amino acids, and will be valuable for rationalizing and predicting the strength of water-mediated interaction involved in the biological activity of proteins.

• 대한토목학회논문집
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• 제37권6호
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• pp.1009-1015
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• 2017

대부분의 도시철도 운영기관은 지방자치단체가 설립하고 운영함에 따라 공공성이 우선시 되고 있으므로 개별 법령에 근거하여 무임승차를 시행하고 있다. 우리나라의 경우 인구 고령화 사회에 접어들면서 도시철도 노인 승객의 증가에 따른 도시철도 운영기관의 재정 적자의 큰 부분으로 경로우대 무임승차가 대두하고 있다. 그러나 현재 경로우대 무임승차에 관한 선행연구가 많이 이뤄지지 않은 실정이며, 특히 민간 투자사업에 대한 무임승차 연구가 필요한 실정이다. 신분당선 무임수송 개선 대안으로 전액 유료화, 70세 미만(65세~69세)유료화, 별도운임 유료화(900원)로 대안을 설정하였다. 별도운임만 유료화(900원)하는 대안이 신분당선(주)의 자체 별도운임으로 연락운임 정산이 필요 없고 정부에서 손실보전을 할 수준이 아니므로 최적의 대안으로 분석되었다.

• Transactions on Electrical and Electronic Materials
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• 제7권5호
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• pp.235-239
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• 2006

Charge dynamics in polymeric materials after aged under ac electric field using the pulsed electroacoustic (PEA) technique is reported. The emphasis is placed on charge decay. The charge dynamics of the ac aged additive free low density polyethylene (LDPE) samples under dc bias differ from the sample without ac ageing, indicating changes brought in by ac ageing. It is believed that a slow decay rate of charge in the ac aged sample is related to the formation of deep traps in the material. However, chemical analysis by infrared spectroscope (FTIR) and Raman microscope reveals no significant chemical changes taken place in the bulk of the material after ac ageing. Further experiments on irradiated LDPE have revealed a similar behaviour, i.e. the charge decay is slower in irradiated samples than that of fresh sample. The findings presented clearly indicate that space charge measurement can be used as a diagnostic tool to monitor ageing in polymeric materials.

• E2M - 전기 전자와 첨단 소재
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• 제7권5호
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• pp.409-416
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• 1994

A double layered photoreceptor using phthalocyanine dye was made by dip-coating method. The under cutting layer(UCL) was coated with A1$\_$2/O$\_$3/ or polyamide, and the charge generation layer(CGL) was formed by .tau.-type metal-free phthalocyanine. The oxadiazole was used as a charge transport layer(CTL) and polycarbonate and poly(vinyl butyral) was employed as a host polymer. The .tau.-H$\_$2/Pc had an absorption peak around 780nm, which coincided with the emitting wavelengths of GaAlAs diode lasers. Maximum charge acceptance of CTL that gives thickness of 12.mu.m was -900V by corona charge of -6.0kV. In photo-induced discharge measurements, residual potential was less than -20V and sufficient for ordinary use, and sample films using of poly(vinyl butyral) was showed good charge retention. In printing test, drum that was employed polycarbonate as a host polymer showed the good print quality.

• ETRI Journal
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• 제27권3호
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• pp.319-325
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• 2005

In this paper the effect of temperature on the electrical properties of organic semiconductor disperse orange dye 25 (OD) have been examined. Thin films of OD have been deposited on $In_{2}O_{3}$ substrates using a centrifugal machine. DC current-voltage (I-V) characteristics of the fabricated devices $(Al/OD/In_{2}O_{3)$ have been evaluated at varying temperatures ranging from 40 to $60^{\circ}C$. A rectification behavior in these devices has been observed such that the rectifying ratio increases as a function of temperature. I-V characteristics observed in $Al/OD/In_{2}O_{3)$ devices have been classified as low temperature $({\leq} 50^{\circ}C)$ and high temperature characteristics (approximately $60^{\circ}C$). Low temperature characteristics have been explained on the basis of the charge transport mechanism associated with free carriers available in OD, whereas high temperature characteristics have been explained on the basis of the trapped space-charge-limited current. Different electrical parameters such as traps factor, free carrier density, trapped carrier density, trap density of states, and effective mobility have been determined from the observed temperature dependent I-V characteristics. It has been shown that the traps factor, effective mobility, and free carrier density increase with increasing values of temperature, whilst no significant change has been observed in the trap density of states.

• Mass Spectrometry Letters
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• 제4권4호
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• pp.71-74
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• 2013

In the present study, we report that the charge-directed (assisted) peptide dissociation products, such as b- and y-type peptide backbone fragments, were the major products in MS/MS and $MS^3$ applications of some o-TEMPO-Bz-C(O)-peptide ions, while radical-driven dissociation products, such as a/x and c/z-type fragments, were previously shown to be the major products in the free radical initiated peptide sequencing mass spectrometry (FRIPS MS). Those o-TEMPO-Bz-C(O)-peptides share a common feature in their sequences, that is, the peptides do not include an arginine residue that has the highest proton affinity among free amino acids. The appearance of b- and y-type fragments as major products in FRIPS MS can be understood in terms of the so-called "mobile-proton model". When the proton is highly mobilized by the absence of arginine, the chare-directed peptide dissociation pathways appear to be more competitive than the radical-driven dissociation pathways, in our FRIPS experiments.

• 전자공학회논문지SC
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• 제48권2호
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• pp.86-90
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• 2011

전계효과 트랜지스터(FETs)를 이용한 전하 검출형 DNA센서는 DNA가 가지고 있는 음전하를 중성화 시키는 양이온의 영향은 매우 중요하다. 본 논문에서는 양이온 농도에 의존하는 Debye length에 관한 연구를 통해 DNA 검출감도를 평가하였다. Debye length는 낮은 농도의 NaCl 용액에서 긴 거리를 유지하며, Debye length가 높은 용액에서 DNA가 가지고 있은 음전하는 게이트 채널에 보다 많은 영향을 미친다. 용액내 NaCl농도가 1 mM인 버퍼 용액에서 상보적 DNA의 hybridization에 의한 전계효과 트랜지스터의 게이전압은 21 mV 시프트 했으며, NaCl 농도가 10 mM인 버퍼 용액에서는 7.2 mV, NaCl농도가 100 mM인 버퍼 용액에서는 전계효과 트랜지스터의 게이트 전압이 5.1 mV 각각 시프트 하였다. 이러한 결과를 바탕으로 전계효과 트랜지스터를 이용한 전하 검출형 DNA센서의 검출 감도는 Debye length에 의존하는 것을 규명하였다.

• 화약ㆍ발파
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• 제34권1호
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• pp.11-18
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• 2016

도심지나 보안건물과 근접한 곳에서 폭약을 사용하는 발파작업이 수행되는 경우 지반진동 및 소음의 영향을 최소화 시킬 필요가 있다. 이러한 지반진동과 소음은 암반의 천공내에 장전된 폭약이 기폭되며 주변 암반을 파괴하고 남은 일부 충격에너지에 의하여 발생된다. 최근 천공 내 U형 철재장약홀더를 삽입하여 충격파의 전파방향을 제어하여 자유면방향으로 파쇄효과를 유지하며 암반 내로 전파하는 충격진동을 감쇄시키는 발파 공법이 제안되었다. 본 연구에서는 U형 철재장약홀더를 적용한 암반발파에서 충격파의 전파특성을 파악하기 위하여, AUTODYN 소프트웨어를 이용하여 장약홀더 내 장전된 폭약의 폭굉을 모사하고 주변암반에 전달된 충격파를 측정하였다. 또한 장약홀더 발파의 암파쇄 효과를 파악하기 위하여 동적파괴과정해석코드인 DFPA(Dynamic Fracture Process Analysis)를 적용하여 장약홀더를 이용한 장약조건을 고려한 2자유면 발파를 모사하였다. 일반발파의 장약조건을 고려한 충격파 발생 및 파괴과정해석을 추가적으로 수행하여 장약홀더의 암파쇄효과를 비교하였다.

• Bulletin of the Korean Chemical Society
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• 제30권1호
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• pp.97-101
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• 2009

A new approach was applied to examine the charge generation and transport in organic photoconductive devices by Monte‐Carlo simulation utilizing multiple site interactions of carriers with all other charges within Coulomb radius. Stepwise generation frame was considered first by a charge separation process that was counted in two separate transactions, i.e., hopping against physical decay and dissociation against recombination. Thereafter, diffusion/ drifting process of free carriers was counted to follow. This method enables to examine readily the photocurrent generated alongside the charge generation efficiency. The field and temperature dependences of the efficiency and photocurrent were obtained comparable to Onsager’s and experimental data.