• 대한전자공학회논문지TC
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• 제39권12호
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• pp.539-546
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• 2002

본 논문에서의 패킷 스케줄러는 무선 채널 환경에서 실시간 비디오 트래픽과 비실시간 인터넷 트래픽을 동시에 서비스한다. 그리고 실시간 트래픽에 대한 지연을 감소 시기키 위하여 누적카운터와 SIR값을 동시에 고려하는 새로운 패킷 스케줄링 알고리즘을 제안한다. 본 알고리즘에서는 실시간 트래픽을 비실시간 트래픽에 비하여 우선적으로 처리한다. 시뮬레이션 결과를 고찰할 때, 실시간 비디오 트래픽과 같이 지연성능에 민감한 서비스의 경우에는 AC(Accumulation Counter) 방식이 기존의 M-LWDF방식보다 더 적합한 알고리즘으로 관찰되었다. 본 논문에서는 HSDPA 시스템과 유사한 구조를 채택하여 시간 축으로는 프레임 주기를 가지며 동시에 코드 축으로는 OVSF 코드를 사용할 수 있는 구조를 채택하여 모의 실험을 수행하였다.

• 수산해양기술연구
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• 제29권3호
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• pp.214-219
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• 1993

Counter balance valve is used as one part of hydraulic motor brake system. The function of this valve is to protect over-run or free falling of inertia load. But occasionally the brake system with counter balance valve makes some undesirable problems such as pressure surges or vibrations. These problems may hurt system safety and driver's conformability. Nevertheless, studies on dynamic characteristics of hydraulic system including counter balance valve are very rare, so further accumulation of research results are required. In this study, for the purpose of easy estimation about dynamic characteristics of hydraulic system including counter balance valve, precise formulation describing fluid dynamics and valve dynamics under various boundary conditions were made. The equations obtained in the preceding process include some parameters that must be got experimentally. Flow coefficients of valve and choke are the most significant ones among the parameters. So these parameters are obtained experimentally in this study, and experimental equations obtained from the experimental data were used for numerical calculation. The equations were analysed by numerical integration using Runge-Kutta method, because the equations contain various nonlinear terms. From the numerical analysis, it was verified that the dynamic response of counter balance valve and pressure variation at each elements can be estimated very easily. So the analysing method developed in this study enabled very easy estimating the relation between the performances of counter balance valve and various physical parameters related to the valve. Conclusively, it is said that the results obtained in this study can be used very usefully to develop a new type counter balance valve or to apply the valve to actual hydraulic system for various industrial equipments.

• Nuclear Engineering and Technology
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• 제34권4호
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• pp.396-405
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• 2002

An experimental study on counter-current flow limitation phenomena in narrow annular passages was carried out The gap sizes tested were 1, 2 and 3 mm. This is very small compared with the outer diameter of the annular passage, 500 mm. It was visually observed that a CCFL might occur in some part of the periphery while the other part is remained in a counter current flow pattern. That is, non-uniform behaviour of fluids due 4o a 2-dimensional effect appear in a large diameter facility. Because of this non-uniformity, a CCFL is defined in the present work as the situation where net water accumulation is sustained. That is, some amount of water should not be allowed to penetrate the gap and accumulate over the gap at CCFL criterion. The measured data are presented in the form of Wallis＇type correlation with characteristic length of gap size. It was found that the present correlation is in good agreement with other empirical correlation based on measurements whose test section diameter is close and the gap size is much larger than that of the present test section.

• 한국대기환경학회지
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• 제21권3호
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• pp.295-301
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• 2005

The fine particles in the range of $30\~500nm$ are monitored at Hanyang University campus in Ansan using house made DMA (differential mobility analyzer) and commercial CPC (condensation particle counter, TSI inc.) in SMPS mode. The monitoring period is March 16th 2004 through May 7th, 2004. During the monitoring period, Aitken nuclei mode $(30\~100nm)$ particle concentration has a tendency of increase in the morning and evening hours. However, the accumulation mode $(100\~500nm)$ particle concentration stays rather stable than that of Aitken mode.

• Toxicological Research
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• 제29권3호
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• pp.211-215
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• 2013

The trace toxic metal copper was assayed using mercury immobilized on a carbon nanotube electrode (MCW), with a graphite counter and a reference electrode. In this study, a macro-scale convection motor was interfaced with a MCW three-electrode system, in which a handmade MCW was optimized using cyclic- and square-wave stripping voltammetry. An analytical electrolyte for tap water was used instead of an expensive acid or base ionic solution. Under these conditions, optimum parameters were 0.09 V amplitude, 40 Hz frequency, 0.01 V incremental potential, and a 60-s accumulation time. A diagnostic working curve was obtained from 50.0 to 350 ${\mu}g/L$. At a constant Cu(II) concentration of 10.0 ${\mu}g/L$, the statistical relative standard deviation was 1.78% (RSD, n = 15), the analytical accumulation time was only 60 s, and the analytical detection limit approached 4.6 ${\mu}g/L$ (signal/noise = 3). The results were applied to non-treated drinking water. The content of the analyzed copper using 9.0 and 4.0 ${\mu}g/L$ standards were 8.68 ${\mu}g/L$ and 3.96 ${\mu}g/L$; statistical values $R^2$ = 0.9987 and $R^2$ = 0.9534, respectively. This method is applicable to biological diagnostics or food surveys.

• 한국응용과학기술학회지
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• 제31권4호
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• pp.663-668
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• 2014

An in-vivo diagnosis of trace Mg(II) ion was performed using a low-cost and environment-friendly voltammetric method, using a graphite counter and reference electrodes and a fluorine-immobilized graphite working electrode, and clean deep seawater was used as an electrolyte solution. Under optimum conditions, the analytical working ranges attained microgram ranges, and a detection limit of $80.6ugL^{-1}$ was obtained using stripping voltammety with 60 sec accumulation time. Ex-vivo application was performed on fish liver and mice droppings. The developed techniques can be applicable to tumor cell analysis.

• 한국응용과학기술학회지
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• 제35권4호
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• pp.1379-1385
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• 2018

The hand held voltammetry systems searched diabetic assay using glucose sensor of fluorine nafion doped carbon nanotube electrode (FCNE). An inexpensive graphite carbon pencil was used as an Ag/AgCl reference and Pt counter electrode. Upon combining and using three electrode systems, optimum square wave (SW) stripping results were attained to 1.0-9.0 ug/L with 8 points. Statistic RSD precision was of 6.02 % with n=15 in 0.1 mg/L glucose. After a total of 200 second accumulation times, analytical detection limit of 0.8 ug/L was obtained. This developed technique was applied to urine samples from diabetic patients urine for fluid analysis, it was determined that the sensor can be used with a diagnostics in the ex vivo of live cells and non treated biological fluid.

• Journal of Electrochemical Science and Technology
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• 제10권2호
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• pp.177-184
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• 2019

An electrochemical detection method for capsaicin has been developed using ionic liquid (IL) doped graphene-titania-Nafion composite-modified electrode. The combination of IL (1-hexyl-3-methylimidazolium with hexafluorophosphate counter ion) in the composite-modified electrode resulted in a significantly increased electrochemical response for capsaicin compared to that obtained at the corresponding electrode without IL. The increased electrochemical signal could be ascribed to the decreased electron transfer resistance through the composite film and also to the effective accumulation of capsaicin on the electrode surface due to ${\pi}-{\pi}$ interaction of the imidazole groups of IL with the aromatic rings of capsaicin. The present IL composite-modified electrode can detect capsaicin with a concentration range from $3.0{\times}10^{-8}M$ to $1.0{\times}10^{-5}M$ with a detection limit of $3.17{\times}10^{-9}M$ (S/N = 3). The present sensor showed good reproducibility (RSD = 3.2%).

• 한국정보통신학회논문지
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• 제20권12호
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• pp.2395-2400
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• 2016

암 환자들을 대상으로 하는 항암치료법은 나노입자, 폴리머 중합체, 지질, 리포솜 등을 치료 전달체로 이용하여 항암치료를 진행하는 방법들이 주로 활발하게 사용되고 있다. 이러한 전달체는 항암 치료제를 직접 암세포로 정확하게 표적 운반하는 정확성, 정확하게 운반한 후 선택적으로 항암치료제를 방출해야하는 유출제어, 다른 일반 세포들을 약물로부터 보호하는 기능 등을 동시에 가지고 있어야 하지만, 대부분 항암약물의 독성에 기인한 부작용이 발생하고 있다. 겸형적혈구는 암세포주변 혈관세포와 멤브레인 표면에 존재하는 리셉터 사이에의 점착성이 존재하며 추가적 생화학처리 없이 암세포 주변에 표적화가 가능함을 보인다. 또한, 암세포 주변의 혈관의 구조적 변화특성은 겸형적혈구의 중합화 반응을 증가시킨다. 따라서 본 논문에서는 겸형적혈구를 이용한 새로운 항암치료법의 효과를 정량적 혈관분석 방법을 통해 제시하고자 한다.

• Bulletin of the Korean Chemical Society
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• 제31권9호
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• pp.2649-2655
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• 2010

$PKC{\delta}$-catalytic V5 Heptapeptide (FEQFLDI, FP7) interacts with heat shock protein 27 (HSP27) and inhibits HSP27-mediated resistance to cell death against various stimuli including radiation therapy. Here, we prepared radio-iodinated heptapeptide and further investigated its uptake properties in HSP27 expression cells. Peptide sequence of FP7 and a negative control peptide (WSLLEKR, QP7) was modified by substituting their C-terminus residue to tyrosine (FP6Y and QP6Y) to label radio-iodine. Iodinated peptides were confirmed by LC mass analysis with cold iodine reaction mixture. Accumulation of [$^{125}I$]iodo-FP6Y and [$^{125}I$]iodo-QP6Y in NCI-H1299 cell line, with higher level of HSP27, and NCI-H460 cell line, with lower level of HSP27, was measured by NaI(Tl) scintillation counter. The modification of substituting C-terminus residue of FP7 to tyrosine (FP6Y) did not affect its interaction with HSP27. Accumulation of [$^{125}I$]iodo-FP6Y in NCI-H1299 cells was 3 fold higher than in NCI-H460 cells. The novel radio-iodinated FP6Y would be used as a tracer for targeting HSP27 protein.