• Journal of the Optical Society of Korea
• /
• 제19권6호
• /
• pp.673-678
• /
• 2015

Terahertz dual-band frequency selective surface filters made by perforating two different rectangular holes in molybdenum have been designed, fabricated and measured. Physical mechanisms of the dual-band resonant responses are clarified by three differently configured filters and the electric field distribution diagrams. The design process is straightforward and simple according to the physical concept and some formulas. Due to the weak coupling between the two neighboring rectangle holes with different sizes in the unit cell, good dual-band frequency selectivity performance can be easily achieved both in the lower and higher bands by tuning dimensions of the two rectangular holes. Three samples are fabricated, and their dual-band characteristics have been demonstrated by a THz time-domain spectroscopy system. Different from most commonly used metal-dielectric structure or metal-dielectric-metal sandwiched filters, the designed dual-band filters have advantages of easy fabrication and low cost, the encouraging results afforded by these filters could find their applications in dual-band sensors, THz communication systems and other emerging THz technologies.

• Nuclear Engineering and Technology
• /
• 제47권5호
• /
• pp.588-595
• /
• 2015

This study presents an effective method for additional recovery of residual actinides in liquid electrodes after the electrowinning process of pyroprocessing. The major distinctive feature of this method is a reactor with multiple reaction cells separated by partition walls in order to improve the recovery yield, thereby using the interelement difference in diffusion coefficients within the liquid electrode and controlling the selectivity and purity of element recovery. Through an example of numerical simulation of the diffusion scenarios of individual elements, we verified that the proposed method could effectively separate the actinides (U and Pu) and rare-earth elements contained in liquid cadmium. We performed a five-step consecutive recovery process using a simplified conceptual reaction cell and recovered 58% of the initial amount of actinides (U + Pu) in high purity (${\geq}99%$).

• Archives of Pharmacal Research
• /
• 제27권6호
• /
• pp.581-588
• /
• 2004

A series of 2, 5-dihydroxychalcones and related compounds were synthesized, and their cyto-toxicities against tumor cell lines and human umbilical venous endothelial cells (HUVEC） eval-uated. It was found that chalcones, with electron-withdrawing substituents on an A ring, exhibited significant cytotoxicities. Among the synthesized compounds, 2'-chlbro-2, 5-dihydrox-ychalcone (9） was most potent, with an $IC_{50}$ value as low as $0.31{\;}{\mu\textrm{g}}/mL$. This compound also exhibited a significant cytotoxic selectivity toward HUVEC.

• Bulletin of the Korean Chemical Society
• /
• 제33권7호
• /
• pp.2359-2364
• /
• 2012

Two new chemosensors, rhodamine 6G derivative bearing hydroxyethyl group (1) and rhodamine base derivative bearing 15-crown-5 group (2) were synthesized and their sensing behaviors toward various metal ions were investigated by UV/Vis and fluorescence spectroscopies. Addition of $Hg^{2+}$ ion to a $CH_3CN$ solution of 1 and 2 gave visual color changes as well as fluorescent OFF-ON observations. Selectivity and sensitivity of 1 towards $Hg^{2+}$ are excellent enough to detect micromolar level of $Hg^{2+}$ ion, even in equeous media and biological sample (HeLa cell).

• Bulletin of the Korean Chemical Society
• /
• 제34권2호
• /
• pp.495-499
• /
• 2013

A novel series of aryl sulfonylpiperazine derivatives (5-15) were synthesized as 5-$HT_6$ ligands. In vitro assay was evaluated by measuring the 5-HT-induced $Ca^{2+}$ increases using HeLa cell line expressing the cloned human 5-$HT_6$ receptor, and the compound 13 showed potent 5-$HT_6$ receptor antagonistic effect with $IC_{50}$ value of 3.9 ${\mu}M$. Compound 13 also showed good selectivity on the 5-$HT_6$ over 5-$HT_4$ and 5-$HT_7$ receptors.

• 한국동물학회:학술대회논문집
• /
• 한국동물학회 2003년도 한국생물과학협회 학술발표대회
• /
• pp.161.2-161
• /
• 2003

No Abstract, See Full Text

• 한국표면공학회지
• /
• 제29권5호
• /
• pp.314-324
• /
• 1996

Scanning probe microscopes (SPMs) such as the scanning tunneling microscope (STM) and the atomic force microscope (AFM) were used for surface modification tools at the nanometer scale. Material surfaces, i. e., titanium, hydrogen-terminated silicon and trimethylsilyl organosilane monolayer on silicon, were locally oxidized with the best lateral spatial resolution of 20nm. The principle behind this proximal probe oxidation method is scanning probe anodization, that is, the SPM tip-sample junction connected through a water column acting as a minute electrochemical cell. An SPM-nanolithogrphy process was demonstrated using the organosilane monolayer as a resist. Area-selective chemical modifications, i. e., etching, electroless plating with gold, monolayer deposition and immobilization of latex nanoparticles; were achieved in nano-scale resolution. The area-selectivity was based on the differences in chemical properties between the SPM-modified and unmodified regions.

• 한국수소및신에너지학회논문집
• /
• 제32권6호
• /
• pp.534-541
• /
• 2021

In this study, a novel microwave-matrix reformer was proposed to convert CH₄, which is a major component, to a high quality hydrogen energy. And to identify this performance, it was investigated for O₂/C ratio, steam feed amount and reformed gas recirculation which are affected for methane conversion and product gas yield. Through the parametric screening studies, optimal operating conditions were that O₂/C ratio, steam feed amount and recirculation rate were 1.1, 10 mL/min and 30 L/min. In this conditions, CH₄ conversion was 68.1%, H₂ selectivity 77.2 and H₂/CO ratio 2.62 which are possible applying SOFC stack for RPG (residential power generator).

• 대한방사성의약품학회지
• /
• 제6권2호
• /
• pp.139-145
• /
• 2020

Polo-like kinase 1 (Plk1) is a key protein in mitosis and has been validated as a target for tumor therapy. It is well known to highly overexpress in many kinds of tumor, which has been implicated as a potential biomarker for tumor treatment and diagnosis. Plk1 consists of two domains, the N-terminus kinase domain and the C-terminus polo-box domain (PBD). The inhibitors have been developed for PBD of Plk1, which were shown a high level of affinity and selectivity for Plk1 that led to mitotic arrest and apoptotic cell death. This review discusses the inhibitors for PBD of Plk1 that are suitable for in vivo tumor treatment. They can be further extended for developing in vivo imaging probes for early diagnosis of tumor.

• ETRI Journal
• /
• 제44권1호
• /
• pp.125-134
• /
• 2022

Visible light communication (VLC) systems incorporate ambient lighting and wireless data transmission, and the experienced channel in indoor VLC is a major topic that should be examined for reliable communication. In this study, it is realized that multiple transmitters in classical alignment are the forceful factors for channel characteristics. In the frequency band, fluctuations with sudden drops are observed, where the fluctuation shape is related to the source layout and receiver location. These varying frequency-selective channels need solutions, especially for mobile users, because sustained channel estimation and equalization are necessary as the receiver changes its location. It is proven that using light-emitting diodes (LEDs) with highly directional beams as sources or using a detector with a narrow field of view (FOV) in the receiver may help partially alleviate the problem; the frequency selectivity of the channel reduces in some regions of the room. For flat fading channel characteristics all over the room, LEDs should be aligned in hexagonal cellular structure, and detector FOV should be arranged according to the cell dimension outcomes.