• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2001.06a
• /
• pp.3-3
• /
• 2001

Recently TiN, TiAlN, CrN hardcoatings have adapted many industrial application such as die, mold and cutting tools because of good wear resistant and thermal stability. However, in terms of high speed process, general hard coatings have been limited by oxidation and thermal hardness drop. Especially in the case of PCB drill, high speed cutting and without lubricant process condition have not adapted these coatings until now. Therefore more recently, superhard nanocomposite coating which have superhard and good thermal stability have developed. In previous works, WC-TiAlN new nanocomposite film was investigated by cathodic arc ion plating system. Control of AI concentration, WC-TiAlN multi layer composite coating with controlled microstructure was carried out and provides additional enhancement of mechanical properties as well as oxidation resistance at elevated temperature. It is noted that microhardness ofWC-TiA1N multi layer composite coating increased up to 50 Gpa and got thermal stability about $900^{\circ}C$. In this study WC-TiAlN nanocomposite coating was deposited on PCB drill for enhancement of life time. The parameter was A1 concentration and plasma cleaning time for edge sharpness maintaining. The characteristic of WC-TiAlN film formation and wear behaviors are discussed with data from AlES, XRD, EDS and SEM analysis. Through field test, enhancement of life time for PCB drill was measured.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2004.10a
• /
• pp.1236-1239
• /
• 2004

The object of this study is to develop a model of the cardiovascular system capable of simulating the short-term transient and steady-state hemodynamic responses such as hypotention and disequilibrium syndrome during hemodialysis or hemofiltration. The model consists of a closed loop 12 lumped-parameter representation of the cardiovascular circulation connected to set-point models of the arterial and cardiopulmonary baroreflexes and 3 compartmental body fluid and solute kinetic model. The hemodialysis model includes the dynamics of sodium, urea, and potassium in the intracellular and extracellular pools, fluid balance equations for the intracellular, interstitial, and plasma volumes. We have presented the results of many different simulations performed by changing a few model parameters with respect to their basal values.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.02a
• /
• pp.223-223
• /
• 2011

헬리콘 플라즈마는 자기장을 이용하여 높은 전자밀도를 가지게 하는 플라즈마 소스이다. 이러한 장점에도 불구하고, 전자석의 크기 때문에 설치가 어렵고, 전자석을 작동시키기 위해 추가 파워에 대한 비용이 필요하며, 플라즈마의 균일도가 좋지 않아 공정에서는 많이 사용되지 못하였다. 이러한 난점은 UCLA의 Chen이 영구자석을 이용한 새로운 개념의 소스를 개발함으로써 풀릴 수 있다. 이 소스는 헬리콘 플라즈마의 높은 저항을 이용하여 여러 개의 헬리콘 소스를 병렬로 연결이 가능하게끔 한다. 본 연구에서는 우선 Helic Code를 이용하여 floating metal end plate의 위치에 따른 플라즈마의 loading resistance를 계산한 후, 플라즈마의 internal 및 external parameter를 각각 single Langmuir probe와 VI-probe를 이용하여 측정하여 비교해 보았다. 헬리콘 플라즈마의 파장에 따른 보강간섭 조건을 맞췄을 경우, 헬리콘 모드로 전환이 낮은 파워에서 이루워지는 것을 external parameter를 통해 확인해 보았다.

• Proceedings of the KIEE Conference
• /
• 1997.07e
• /
• pp.1830-1833
• /
• 1997

This paper describes the electron transport characteristic in $SiH_4$ gas calculated for range of E/N values from $0.5{\sim}300$(Td) using a set of electron collision cross sections determined by the authors and the values of electron swarm parameters are obtained for TOF method. The results gained that the value of an electron swarm parameter such as the electron drift velocity, longitudinal and transverse diffusion coefficients with the experimental and theoretical for a range of E/N. The electron energy distributions function were analysed in monosilane at E/N : 30, 50(Td) for a case of equilibrium region in the mean electron energy. The validity of the results obtained has been confirmed by a TOF method.

• Proceedings of the KIEE Conference
• /
• 2005.10a
• /
• pp.89-92
• /
• 2005

Using quantitative simulations of weakly ionized plasma, we can analyze gas characteristic. In this paper, the electron transport characteristic in $CH_4$ has been analysed over the E/N range 0.1${\sim}$ 300(Td), at the 300($_{\circ}$ K) by the two term approximation Boltzmann equation method and Monte Carlo Simulation. The electron energy distribution function has been analysed in $CH_4$ at E/N=10, 100 for a case of the equilibrium region in the mean energy. The result of Boltzmann equation and Monte Carlo Simulation has been compared with experimental data by Ohmori, $Lucas^{[18]}$ and Carter. The swarm parameter from the swarm study are expected to sever as a critical test of current theories of low energy scattering by atoms and molecules.

• Journal of Biomedical Engineering Research
• /
• v.17 no.4
• /
• pp.545-552
• /
• 1996

Researches on chromosome are very significant in cytogenetics since a gene of the chromosome controls revelation of the inheritance plasma The human chromosome analysis is widely used to diagnose genetic disease and various congenital anomalies. Many researches on automated chromosome karyotype analysis has been carried out, some of which produced commercial systems. However, there still remains much room for improving the accuracy of chromosome classification. In this paper, we propose an algorithm for reconstruction of the chromosDme image to improve the chromosome classification accuracy. Morphological feature parameters are extracted from the reconstructed chromosome images. The reconstruction method from chromosome image is the 32 direction line algorithm. We extract three morphological feature parameters, centromeric index(C.I.), relative length ratio(R.L.), and relative area ratio(R.A.), by preprocessing ten human chromosDme images. The experimental results show that proposed algorithm is better than that of other researchers'comparing by feature parameter errors.

• Applied Chemistry for Engineering
• /
• v.26 no.4
• /
• pp.495-504
• /
• 2015

This work investigated the characteristics of a packed-bed plasma reactor system and the performances of the plasma reactors connected in series or in parallel for the decomposition of ethylene. Before the discharge ignition, the effective capacitance of the ${\gamma}$-alumina packed-bed plasma reactor was larger than that of the reactor without any packing, but after the ignition the effective capacitance was similar to each other, regardless of the packing. The energy of electrons created by plasma depends mainly on the electric field intensity, and was not significantly affected by the gas composition in the range of 0~20% (v/v) oxygen (nitrogen : 80~100% (v/v)). Among the various reactive species generated by plasma, ground-state atomic oxygen and ozone are understood to be primarily involved in oxidation reactions, and as the electric field intensity increases, the amount of ground-state atomic oxygen relatively decreases while that of nitrogen atom increases. Even though there are many parameters affecting the performance of the plasma reactor such as a voltage, discharge power, gas flow rate and residence time, all parameters can be integrated into a single parameter, namely, specific input energy (SIE). It was experimentally confirmed that the performances of the plasma reactors connected in series or in parallel could be treated as a function of SIE alone, which simplifies the scale-up design procedure. Besides, the ethylene decomposition results can be predicted by the calculation using the rate constant expressed as a function of SIE.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.11a
• /
• pp.363-363
• /
• 2008

The development of dry etching process for sapphire wafer with plasma has been key issues for the opto-electric devices. The challenges are increasing control and obtaining low plasma induced-damage because an unwanted scattering of radiation is caused by the spatial disorder of pattern and variation of surface roughness. The plasma-induced damages during plasma etching process can be classified as impurity contamination of residual etch products or bonding disruption in lattice due to charged particle bombardment. Therefor, fine pattern technology with low damaged etching process and high etch rate are urgently needed. Until now, there are a lot of reports on the etching of sapphire wafer with using $Cl_2$/Ar, $BCl_3$/Ar, HBr/Ar and so on [1]. However, the etch behavior of sapphire wafer have investigated with variation of only one parameter while other parameters are fixed. In this study, we investigated the effect of pressure and other parameters on the etch rate and the selectivity. We selected $BCl_3$ as an etch ant because $BCl_3$ plasmas are widely used in etching process of oxide materials. In plasma, the $BCl_3$ molecule can be dissociated into B radical, $B^+$ ion, Cl radical and $Cl^+$ ion. However, the $BCl_3$ molecule can be dissociated into B radical or $B^+$ ion easier than Cl radical or $Cl^+$ ion. First, we evaluated the etch behaviors of sapphire wafer in $BCl_3$/additive gases (Ar, $N_2,Cl_2$) gases. The behavior of etch rate of sapphire substrate was monitored as a function of additive gas ratio to $BCl_3$ based plasma, total flow rate, r.f. power, d.c. bias under different pressures of 5 mTorr, 10 mTorr, 20 mTorr and 30 mTorr. The etch rates of sapphire wafer, $SiO_2$ and PR were measured with using alpha step surface profiler. In order to understand the changes of radicals, volume density of Cl, B radical and BCl molecule were investigated with optical emission spectroscopy (OES). The chemical states of $Al_2O_3$ thin films were studied with energy dispersive X-ray (EDX) and depth profile anlysis of auger electron spectroscopy (AES). The enhancement of sapphire substrate can be explained by the reactive ion etching mechanism with the competition of the formation of volatile $AlCl_3$, $Al_2Cl_6$ or $BOCl_3$ and the sputter effect by energetic ions.

• Journal of Food Hygiene and Safety
• /
• v.5 no.1
• /
• pp.7-12
• /
• 1990

The disposition of Brazilin including plasma concentration-time profiles, excretions via urine and bile, and plasma protein binding was investigated after intravenous or oral administration of radio labeled Brazilin ($^3H-Brazilin$) to male Wistar rats. The main pharmac:okinetic parameters were as follows; $t\;_{ 1/2}$, 13.71 hr; AUC, $53.38\;\mu\textrm{g}{\cdot}hr/ml$; AUMC, $1013.4I\;\mu\textrm{g}{\cdot}hr^2/ml$, MRT, 18.95 hr; Vss, 17778 mllkg and CL, 936.77 ml/hr.kg. The 2nd peak was found in the plasma concentration-time profiles indicating potential enterohepatic circulation. The enterohepatic circulation was supported by the bile excretion. After oral administration, about 64.4 % of administered radioactivity was excreted into the bile within 10 hours and its excretion rate reached maximum at 3 hours after administration. The Vss was extremely high, 17.8 l/kg indicating distribution of brazilin in most organs (tissues) with high concentration of brazilin in some organs. Brazilin was distributed into most of organs (spleen, adrenal, pancreas, kidney, thymus, lung, heart, liver, prostate, epididymus, testis, fat, muscle and done) except brain. High concentration of Brazilin was detected especially in liver, kidney, epididymus and testis. Approximately, 62.9% and 44.1% of the dose was excreted for intravenous and oral administration, respectively. About 80% of the dose eventually excreted into urine was excreted within 24 hr after dosing. Plasma protein binding of brazilin resulted in $40\;{\pm}\;4%$ by ultrafiltration method.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.529-529
• /
• 2013

플라즈마를 진단하는 데에는 장비적으로나 현실적으로 많은 제약이 따른다. 따라서 측정 할 수 있는 parameter가 적다. 그리고 진단 장비의 성능에 따라서 측정된 data의 신뢰도가 결정된다. 그래서 플라즈마에 레이저를 쏘아서 생성되는 솔리톤의 RADIATION을 이용하여 플라즈마의 특성을 파악하려고 한다. 본 시뮬레이션은 Particle-In-Cell (PIC) 시뮬레이션을 이용하여 Underdense 플라즈마에 Terahertz 레이저를 쏘았을 경우 발생되는 솔리톤의 특성을 파악하였다. 2D 시뮬레이션으로 수행하였으며 플라즈마는 Underdense 플라즈마를 이용하였다. 레이저 Focusing 점의 위치와 솔리톤의 주파수, 플라즈마의 밀도 gradient 에 따른 솔리톤의 이동 및 특징, 플라즈마 밀도에 따른 솔리톤의 특징을 살펴보았다.