• Venture DIGEST
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• no.2 s.127
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• pp.21-23
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• 2009

태극마크 물결무늬 USB, 큐빅이 박힌 쥬얼리 USB, 교통카드 USB, 스폰지밥 캐릭터 USB, 자물쇠 USB${\dots}$. (주)메모렛월드(대표 최백수, www.memorette.co.kr)의 USB메모리를 소개하자면 일단 숨이 벅차다. 다양한 종류에 독특한 디자인이 한 달이 멀다하고 쏟아져 나오고 있다. 고객의 다양한 니즈를 겨냥한 만큼 '충성고객층'도 두텁다. 국내 USB메모리 시장을 선도하고 있는 (주)메모렛월드를 찾아가봤다.

• Venture DIGEST
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• no.2 s.127
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• pp.48-49
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• 2009

국내 최초 아이디어 경매쇼'를 표방하며 벤처기업인들의 반짝이는 아이디어와 제품을 선보이는 TV프로그램이 화제다. 매주 목요일 저녁 6시 30분부터 SBS에서 방송되는 '아이디어 하우머치(tv.sbs.co.kr/howmuch)'가 바로 그것. 경매라는 역동적인 포맷을 통해 참신한 제품에 투자자를 연결해주는 아이디어 하우머치를 제작 연출하고 있는 '필름잇다우' 최희성 대표를 만나봤다. 세계 1위의 중소벤처기업 기술이 대한민국 경제의 유일한 희망이라는 믿음을 갖고, 벤처기술 홍보와 이미지제고를 위해 뛰고 있는 그에게 몇 가지 질문을 던져본다.

• Publications of The Korean Astronomical Society
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• v.16 no.1
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• pp.25-29
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• 2001

We obtained three-color composite. images of 78 celestial objects most of which are listed in Messier catalogue. In order to make color images, 118 raw image sets were taken with B, V, R, I and H-alpha filters. We used the 2k CCD camera attached to the 1.8 m telescope of Bohyunsan Optical Astronomy Observatory. These composite images are to be used for educational purposes or public releases. The images are presented on the website, http://www.boao.re.kr/-ybjeon/boao_images.htrnl.

• 연구논문집
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• s.25
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• pp.115-120
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• 1995

The aim of this project is the development of technology of production of micro mechanical parts. Materials are Cr, pt or film (thickness $1000-3000\AA$) on glass substrate. Method of manufacturing is resistless direct laser ablation based on the projection technology. A source of radiation is KrF excimer laser(248nm), Experiments of threshold energy are carried out and the results are analyzed by SEM.

• Korean Journal of Mathematics
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• v.27 no.2
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• pp.487-503
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• 2019

In this study, the author provided a discussion on one dimensional Laplace and Fourier transforms with their applications. It is shown that the combined use of exponential operators and integral transforms provides a powerful tool to solve space fractional partial differential equation with non - constant coefficients. The object of the present article is to extend the application of the joint Fourier - Laplace transform to derive an analytical solution for a variety of time fractional non - homogeneous KdV. Numerous exercises and examples presented throughout the paper.

• Korean Journal of Metals and Materials
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• v.50 no.5
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• pp.395-400
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• 2012

In this study, we have investigated the surface morphology of hydroxyapatite (HA) coated Ti alloy surface using pulsed laser plating. The HA (tooth ash) films were grown by pulsed KrF excimer laser, film surfaces were analyzed for topology, chemical composition, crystal structure and electrochemical behavior. The Ti-6Al-4V alloy showed ${\alpha}$ and ${\beta}$ phase, Cp-Ti showed ${\alpha}$ phase and the HA coated surface showed HA and Ti alloy peaks. The HA coating layer was formed with $1-2{\mu}m$ droplets and grain-like particles, particles which were smaller than the HA target particle, and the composition of the HA coatings were composed of Ca and P. From the electrochemical test, the pitting potential (1580 mV) of HA coated Ti-6Al-4V alloy was higher than those of Cp-Ti (1060 mV) and HA coated Cp-Ti (1350 mV). The HA coated samples showed a lower current density than non-HA coated samples, whereas, the polarization resistance of HA coated samples showed a high value compared to non-HA coated samples.

• The Korean Journal of Physiology and Pharmacology
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• v.14 no.5
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• pp.305-310
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• 2010

The human $ether$-$a$-$go$-$go$-related gene ($hERG$) channel is important for repolarization in human myocardium and is a common target for drugs that prolong the QT interval. We studied the effects of two antipsychotics, tiapride and sulpiride, on hERG channels expressed in $Xenopus$ oocytes and also on delayed rectifier $K^+$ currents in guinea pig cardiomyocytes. Neither the amplitude of the hERG outward currents measured at the end of the voltage pulse, nor the amplitude of hERG tail currents, showed any concentration-dependent changes with either tiapride or sulpiride ($3{\sim}300{\mu}M$). However, our findings did show that tiapride increased the potential for half-maximal activation ($V_{1/2}$) of HERG at $10{\sim}300{\mu}M$, whereas sulpiride increased the maximum conductance ($G_{max}$) at 3, 10 and $100{\mu}M$. In guinea pig ventricular myocytes, bath applications of 100 and $500{\mu}M$ tiapride at $36^{\circ}C$ blocked rapidly activating delayed rectifier $K^+$ current ($I_{Kr}$) by 40.3% and 70.0%, respectively. Also, sulpiride at 100 and $500{\mu}M$ blocked $I_{Kr}$ by 38.9% and 76.5%, respectively. However, neither tiapride nor sulpiride significantly affected the slowly activating delayed rectifier $K^+$ current ($I_{Ks}$) at the same concentrations. Our findings suggest that the concentrations of the antipsychotics required to evoke a 50% inhibition of IKr are well above the reported therapeutic plasma concentrations of free and total compound.

• Journal of Advanced Marine Engineering and Technology
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• v.20 no.5
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• pp.93-102
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• 1996

Laser-induced plume and laser-target interaction during pulsed laser deposition are demonstrated for a lead zirconate titanate (PZT). A KrF excimer laser (wavelength 248nm) was used and the laser was pulsed at 20Hz, with nominal pulse width of 20ns. The laser fluence was~$16J/cm^2,$ with 100mJ per pulse. The laser-induced plasma plume for nanosecond laser irradiation on PZT target has been investigated by optical emission spectra using an optical multichannel analyzer(OMA) and by direct observation of the plume using an ICCD high speed photography. OMA analysis showed two distinct ionic species with different expansion velocities of fast or slow according to their ionization states. The ion velocity of the front surface of the developing plume was about $10^7$cm/sec and corresponding kinetic energy was about 100eV. ICCD photograph showed another kind of even slower moving particles ejected from the target. These particles considered expelled molten parts of the target. SEM morphologies of the laser irradiated targets showed drastic melting and material removal by the laser pulse, and also showed the evidence of the molten particle ejection. The physics of the plasma(plume) formation and particle ejection has been discussed.

• The Korean Journal of Physiology and Pharmacology
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• v.5 no.5
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• pp.367-371
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• 2001

The chromosome 7-linked long QT syndrome (LQT2) is caused by mutations in the human ether-a- go-go-related gene (HERG) that encodes the rapidly activating delayed rectifier $K^+$ current, $I_{Kr},$ in cardiac myocytes. Different types of mutations have been identified in various locations of HERG channel. One of the mechanisms for the loss of normal channel function is due to membrane trafficking of channel protein. The decreased channel function in some deletion mutants appears to be due to loss of coupling with wild type HERG to form the functional channel as the tetramer. Most of missense mutants with few exceptions could interact with wild type HERG to form functional tetramer and caused dominant negative suppression with co-injection with wild type HERG showing variable effects on current amplitude, voltage dependence, and kinetics of activation and inactivation. Two missense mutants at pore regions of HERG found in Japanese LQT2 (A614V and V630L) showed accentuated inward rectification due to a negative shift in steady-state inactivation and fast inactivation. One mutation in S4 region (R534C) produced a negative shift in current activation, indicating the S4 serving as the voltage sensor and accelerated deactivation. The C-terminus mutation, S818L, could not express the current by mutant alone and did not show dominant negative suppression with co-injection of equal amount of wild type cRNA. Co-injection of excess amount of mutant with wild type produced dominant negative suppression with a shift in voltage dependent activation. Therefore, multiple mechanisms are involved in different mutations and functional abnormality in LQT2. Further characterization with the interactions between various mutants in HERG and the regulatory subunits of the channels (MiRP1 and minK) is to be clarified.

• Journal of Microbiology and Biotechnology
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• v.22 no.6
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• pp.818-825
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• 2012

Keratinases are exciting keratin-degrading enzymes; however, there have been relatively few studies on their immobilization. A keratinolytic protease from Chryseobacterium sp. kr6 was purified and its partial sequence determined using mass spectrometry. No significant homology to other microbial peptides in the NCBI database was observed. Certain parameters for immobilization of the purified keratinase on chitosan beads were investigated. The production of the chitosan beads was optimized using factorial design and surface response techniques. The optimum chitosan bead production for protease immobilization was a 20 g/l chitosan solution in acetic acid [1.5% (v/v)], glutaraldehyde ranging from 34 g to 56 g/l, and an activation time between 6 and 10 h. Under these conditions, above 80% of the enzyme was immobilized on the support. The behavior of the keratinase loading on the chitosan beads surface was well described using the Langmuir model. The maximum capacity of the support ($q_m$) and dissociation constant ($K_d$) were estimated as 58.8 U/g and 0.245 U/ml, respectively. The thermal stability of the immobilized enzyme was also improved around 2-fold, when compared with that of the free enzyme, after 30 min at $65^{\circ}C$. In addition, the activity of the immobilized enzyme remained at 63.4% after it was reused five times. Thus, the immobilized enzyme exhibited an improved thermal stability and remained active after several uses.