• 멤브레인
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• 제11권3호
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• pp.109-115
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• 2001

Polypropylene(PP)을 지지막으로 하여 in-situ 가교결합(cross-linking)방식을 이용한 pore-filled 이온교환막을 제조하였다. 다공성 PP막의 기공에 poly(vinylbenzyl chloride)(PVBCI)과 piperazine(PIP), 또는 1,4-diaminobicyclo [2,2,2]octane(DABCO)을 dimethylforamid(DMF)에 녹인 용액을 채워서 겔화시킨 후, 남아있는 chloromethyl 그룹에 trimethylamine을 이용하여 양이온인 암모니움 site를 형성시키면 pore-filled 음이온교환막이 형성된다. 이와 같은 2단계의 제조방식으로 제조된 pore-filled 분리막은 크기의 변화가 없이 안정되며, PVBCI의 농도와 가교제의 농도로써 고분자-겔의 함량(mass gain, MG)과 가교도가 간단하게 조절되는 것을 보여주었다. 특히 아주 낮은 압력(100 kPa)에서의 높은 수투과도(7.9kg/$m^2$hr, 지지막은 PP3, 73%의 MG, 10%의 가교도, PIP 가교제사용)는 연수용 분리막으로 충분히 활용될 수 있음을 보여준다.

• 한국항해항만학회지
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• 제37권4호
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• pp.383-390
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• 2013

해상교통안전진단제도가 해사안전법(구. 해상교통안전법)에 명시(2009. 5. 27)되어 제도적 기반을 구축한 이후 개선을 위한 지속적인 노력은 계속되어 왔으나 아직까지 제도의 고도화를 위한 종합적이고 체계적인 검토가 이루어지지 못하고 있는 실정이다. 이에, 본 연구는 메타평가에 관한 이론을 토대로 설계된 해상교통안전진단제도의 메타평가 분석틀, 즉 'PIP'OU 메타평가 모형'을 적용, 진단활동 전반에 대한 메타평가를 실시하여 현황 및 문제점을 분석하고 개선방안을 제시하였다. 그 결과, 진단 관련자들은 진단활동 자체가 제도의 목적에 부합하고 있으나 운영 측면은 미흡하여 '진단계획' 영역을 중심으로 개선이 필요하고 특히, 관련 이해당사자간 시각차를 최소화 할 수 있는 방안을 함께 고려하여야 하는 것으로 분석되었다. 본 연구는 제도 개선사항의 시급성을 정량화하여 우선순위를 제안함으로써 향후 관련 정책의 체계적인 개선에 활용될 수 있을 것으로 기대한다.

• Journal of Electrochemical Science and Technology
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• 제13권4호
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• pp.431-437
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• 2022

As one of the most hazardous and deadliest pathogens, Listeria monocytogenes (LM) posed various serious diseases to the human being, thus designing effective strategy for its detection is of great significance. In this work, by preparing Ti₃C₂T_x MXenes nanoribbon (Ti₃C₂T_xR) as carrier and selecting thionine (Th) acted simultaneously as signal probe and functional monomer, a LM pathogen-imprinted polymers (PIP) integrated probe electrochemical sensor was design to monitor LM for the first time, that was carried out through the electropolymerization of Th on the Ti₃C₂T_xR/GCE surface in the existence of LM. Upon eluting the templates from the LM imprinted cavities, the fabricated PIP/Ti₃C₂T_xR/GCE sensor can rebound LM cells effectively. By recording the peak current of Th as the response signal, it can be weakened when LM cell was re-bound to the LM imprinted cavity on PIP/Ti₃C₂T_xR/GCE, and the absolute values of peak current change increase with the increasement of LM concentrations. After optimizing three key parameters, a considerable low analytical limit (2 CFU mL^-1) and wide linearity (10-10⁸ CFU mL^-1) for LM were achieved. In addition, the experiments demonstrated that the PIP/Ti₃C₂T_xR sensor offers satisfactory selectivity, reproducibility and stability.

• Journal of electromagnetic engineering and science
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• 제11권2호
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• pp.128-132
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• 2011

In interference tolerance based spectrum sharing systems, primary receivers (PRs) are protected by a predefined peak or average interference power constraint. To implement such systems, cognitive radio (CR) transmitters are required to adjust their transmit power so that the interference power received at the PR receivers is kept below the threshold value. Hence, a CR-transmitter requires knowledge of its channel and the primary receiver in order to allocate the transmit power. In practice, it is impossible or very difficult for a CR transmitter to have perfect knowledge of this channel state information (CSI). In this paper, we investigate the impact of imperfect knowledge of this CSI on the performances of both a primary and cognitive radio network. For fixed transmit power, average interference power (AIP) constraint can be maintained through knowledge of the channel distribution information. To maintain the peak interference power (PIP) constraint, on the other hand, the CR-transmitter requires the instantaneous CSI of its channel with the primary receiver. First, we show that, compared to the PIP constraint with perfect CSI, the AIP constraint is advantageous for primary users but not for CR users. Then, we consider a PIP constraint with imperfect CSI at the CR-transmitter. We show that inaccuracy in CSI reduces the interference at the PR-receivers that is caused by the CR-transmitter. Consequently the proposed schemes improve the capacity of the primary links. Contrarily, the capacities of the CR links significantly degrade due to the inaccuracy in CSI.

• 대한전자공학회논문지TC
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• 제42권12호
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• pp.53-62
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• 2005

본 논문은 휴대인터넷시스템의 수동피코셀 제안과 엑세스포인트와 수동형 피코셀간의 Radio over Fiber(ROF)접속 구도에 대한 것이다. 휴대인터넷시스템(Wibro)은 시속 60km의 중속도의 이동 단말에 50Mbps의 IP 기반 데이터서비스를 제공하는 것이다. 따라서, 서비스를 제공하기 위하여 초기에 셀의 구축비용을 최소화 하는 것이 요구된다. 본 논문은 이러한 요구사항을 만족하는 수동형 피코셀을 제안하고 이의 접속구도에 대하여 제안한 것이다. 기존의 Fabry-Perot(FP) 레이저를 채용하는 ROF 링크의 특성과 수동형Electro-absorption Modulator(EAM)를 이용한 수동형 피코셀의 특성을 측정하여 Wibro시스템에 이의 접속 가능성을 보이고 수동형피코셀의 RF 커버리지를 해석하여 가능성을 검증하였다.

• 한국군사과학기술학회지
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• 제17권2호
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• pp.265-274
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• 2014

A recent air defense missile system(ADMS) is required to have a capability to intercept super-high speed targets such as tactical ballistic missiles(TBMs) by performing engagement control efficiently. The air defense missile system should be ready to engage the TBMs as soon as the ADMS detects TBMs because falling velocity of TBM is very high and remaining time interval to engage TBM is very short. As a result, the ADMS has to predict the trajectories of TBMs accurately with estimated states of dynamics to generate predicted intercept point(PIP). In addition, it is needed to engage TBMs accurately via transmitting the obtained PIP data to the corresponding intercept missiles. In this paper, an analysis about the relationship between ballistic coefficient and PIP accuracy which is depending on geodetic height of the first detection of TBM is included and an issue about effective engagement control for the TBM is considered.

• Korean Journal of Chemical Engineering
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• 제35권12호
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• pp.2487-2495
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• 2018

Inspired by the specific amino acid sequence Asn-Pro-Ala (NPA) of water channel aquaporins (AQPs), we fabricated polyamide (PA) nanofiltration (NF) membranes by introducing reduced glutathione (GSH) in interfacial polymerization (IP) method. Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectrometry (XPS), scanning electron microscope (SEM), atomic force microscopy (AFM), zeta potential and static water contact angle measurement were employed to characterize the chemical composition, morphology, electronegativity and hydrophilicity of the NF membranes. The water flux of GSH/PIP-TMC NF membrane reached $32.00L\;m^{-2}h^{-1}$ at 0.2 MPa, which was approximately twice than that of pristine PIP-TMC NF membrane when the ratio of GHS to piperazidine (PIP) was 40% during IP process. More water channels were built as GSH was embedded into PA layer. The fabricated NF membranes also took on potent rejection for dyes and $Na_2SO_4$. This study presents a simple and facile method to simulate water channels-based biological materials which may find potential application in water treatment.

• 유통과학연구
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• 제20권4호
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• pp.51-63
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• 2022

Purposes: The purpose of this study is to develop and test a possible model that investigates the relationships between green investment, CSR disclosure, social collaboration initiatives, and firm distribution performance to deal with environmental change because it's become the major stakeholder since it affects increasingly global company performance index. Research methodology: In this study a quantitative method was adopted. The 220 respondents were owners and managers of manufacturing enterprises from Indonesia. The structural equation model (SEM) was used to test the hypotheses, and the Partial Least Square (SmartPLS) was used as the data analysis tool. Findings: The study's finding shows that green investment has a significant effect on CSR disclosure, and CSR disclosure has a positive relationship with social collaborative initiatives and the firm's distribution performance. Similarly, social collaborative initiatives also significantly impact a firm's distribution performance. Limitations: This study uses variables that are still abstract and have not been able to regress the dimensions contained there into conclusion variables for each antecedent variable. In addition, this study only used a sample with a small scope, namely Central Java Province, Indonesia. Contribution: The findings of this study contribute to the body of literature in the field of organizational management and support the agency and stakeholder theories. For the practical contribution, this study provides the way to build and implement green-based investment strategies as a competitive edge and improve firm's distribution performance.

• 한국식물생명공학회:학술대회논문집
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• 한국식물생명공학회 2005년도 추계학술대회 및 한일 식물생명공학 심포지엄
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• pp.71-80
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• 2005

Effects of low temperature ($8^{\circ}C$) on the hydraulic conductivity of young roots of a chilling-sensitive (cucumber; Cucumis sativus L.) and a chilling-resistant (figleaf gourd; Cucurbita ficifolia Bouche) crop have been measured at the levels of whole root systems (root hydraulic conductivity, $Lp_r$) and of individual cortical cells (cell hydraulic conductivity, Lp). In figleaf gourd, there was a reduction only in hydrostatic $Lp_r$ but not in osmotic $Lp_r$ suggesting that the activity of water channels was not much affected by low root temperature (LRT)treatment in this species. Changes in cell Lp in response to chilling and recovery were similar asroot level, although they were more intense at the root level. Roots of figleaf gourd recovered better from LRT treatment than those of cucumber. In figleaf gourd, recovery (both at the root and cell level) often resulted in Lp and $Lp_r$ values which were even bigger than the original, i.e. there was an overshoot in hydraulic conductivity. These effects were larger forosmotic (representing the cell-to-cell passage of water) than for hydrostatic $Lp_r$. After a short term (1 d) exposure to $8\;^{\circ}C$ followed by 1 d at $20\;^{\circ}C$, hydrostatic $Lp_r$ of cucumber nearly recovered and that of figleaf gourd still remained higher due to the overshoot. On the contrary, osmotic $Lp_r$ and cell Lp in both species remained high by a factor of 3 as compared to the control, possibly due to an increased activity of water channels. After pre-conditioning of roots at LRT, increased hydraulic conductivitywas completely inhibited by $HgCl_2$ at both the root and cell levels. Different from figleaf gourd, recovery from chilling was not complete in cucumber after longer exposure to LRT. It is concluded that at LRT, both changes in the activity of aquaporins and alterations of root anatomy determine the water uptake in both species. To better understand the aquaporin function in plants under various stress conditions, we examined the transgenic Arabidopsisand tobacco plants that constitutively overexpress ArabidopsisPIP1;4 or PIP2;5 under various abiotic stress conditions. No significant differences in growth rates were found between the transgenic and wild-type plants under favorable growth conditions. By contrast, overexpression of PIP1;4 or PIP2;5 had a negative effect on seed germination and seedling growth under drought stress, whereas it had a positive effect under cold stress and no effect under salt stress. Measurement of water transport by cell pressure probe revealed that these observed phenotypes under different stress conditions were closely correlated with the ability of water transport by each aquaporin in the transgenic plants. Together, our results demonstrate that PIP-type aquaporins play roles in seed germination, seedling growth, and stress response of Arabidopsis and tobacco plants under various stress conditions, and emphasize the importance of a single aquaporin-mediated water transport in these cellular processes.

• 생명과학회지
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• 제32권12호
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• pp.938-946
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• 2022

본 연구는 대풍자 에탄올 추출물에 대한 항산화 활성 및 주름생성 억제 활성을 확인하고자 하였다. 대풍자 에탄올 추출물의 항산화 활성을 확인하기 위하여 DPPH와 ABTS⁺ radical 소거능을 측정하였고 그 결과 추출물 1,000 ㎍/ml 농도에서 각각 73.5%와 74.4%의 높은 소거능을 나타냈다. 주름생성 억제 활성을 확인하기 위하여 collagenase 저해 활성을 실험하였으며, 그 결과 추출물 1,000 ㎍/ml 농도에서 78.8%의 유의할만한 우수한 결과를 보였다. 또한 추출물에 대한 세포의 독성을 확인하기 위해 MTT assay를 수행하였으며, 50 ㎍/ml 이하의 농도에서 약 91.7%의 생존율을 보여, 이후의 세포 실험은 50 ㎍/ml 이하의 농도에서 진행하였다. 섬유아세포인 CCD-986sk에 UVB (20 mJ/cm²)의 자극을 주고 대풍자 에탄올 추출물을 농도별로 처치한 후 procollagen type I과 MMP-1의 발현에 대한 영향을 확인하고자 ELISA 및 RT-PCR 분석을 하였다. 그 결과 대풍자 에탄올 추출물은 PIP의 생합성과 mRNA 발현은 농도의존적으로 증가하였으며, 특히 UVB만 자극한 Cont (각각의 생합성율은 50.3%와 45.8%)과 비교하였을 때 50 ㎍/ml의 농도에서 각각 약 64.2%와 83.4%의 생합성을 보였다. MMP-1의 protein과 mRNA 발현에 대한 결과는 농도의존적으로 감소했음을 확인하였으며, 50 ㎍/ml의 농도에서 각각 약 48.7%와 35.9%의 낮은 발현율을 보였다. 이와 같은 결과를 바탕으로 본 연구는 대풍자 에탄올 추출물이 주름억제 기능성 소재로써의 활용 가능성을 제시해 줄 것으로 사료된다.