• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2002년도 ITC-CSCC -3
• /
• pp.1984-1987
• /
• 2002

This paper describes the design and implementation of a single-chip digitally synthesized 0-35MHz agile function generator. The chip comprises an integrated direct digital synthesizer (DDS) with a 10-bit on- chip digital-to-analog converter (DAC) using an n-well single-poly triple-metal 0.5-$\mu\textrm{m}$ CMOS technology. The main features of the chip include maximum clock frequency of 100 MHz at 3.3-V supply voltage, 32-bit frequency tuning word resolution, 12-bit phase tuning word resolution, and an on-chip 10-bit DAC. The chip provides sinusoidal, ramp, saw-tooth, and random waveforms with phase and frequency modulation, and power-down function. At 100-MHz clock frequency, the chip covers a bandwidth from dc to 35 MHz in 0.0233-Hz frequency steps with 190-ns frequency switching speed. The complete chip occupies 12-mm$^2$die area and dissipates 0.4 W at 100-MHz clock frequency.

• 천문학회보
• /
• 제44권2호
• /
• pp.52.3-52.3
• /
• 2019

We present our first attempt at understanding the dual impact of the large-scale density and velocity environment on the formation of very first astrophysical objects in the Universe. Following the recently developed quasi-linear perturbation theory on this effect, we introduce the publicly available initial condition generator of ours, BCCOMICS (Baryon Cold dark matter COsMological Inital Condition generator for Small scales), which provides so far the most self-consistent treatment of this physics beyond the usual linear perturbation theory. From a suite of uniform-grid simulations of N-body+hydro+BCCOMICS, we find that the formation of first astrophysical objects is strongly affected by both the density and velocity environment. Overdensity and streming-velocity (of baryon against cold dark matter) are found to give positive and negative impact on the formation of astrophysical objects, which we quantify in terms of various physical variables.

• 한국대기환경학회지
• /
• 제10권1호
• /
• pp.24-31
• /
• 1994

Hourly variation of gaseous nitrous acid( HNO$_2$) concentration in Seoul air was monitored from Jan. 11 to SeP. 12, Nitrous acid concentration was determined by DS/IC over nine months of observation, HNO$_2$ range from 0.04 ppb to 5.5 ppb. Gor-tex tube as gaseous HNO$_2$generator in this study is thought to be more convenient and reproducible device than previous generator. As a result of NaOH instead of Na$_2$ CO$_3$/NaHCO$_3$ solution as the IC eluent, we could obtain more stable baseline. The concentration of the NaOH eluent was 15 mM . The limit of detection(3$\sigma$) of the liquid- Phase and gas phase nitrous acid of this method are 1.1ng/$m\ell$ , 0.04 n $\ell$ / $\ell$, respectively. The precisions evaluated by 10 replicate analysis of standard solution and standard gas generated are $\pm$1.59, $\pm$2. 89% RSD, respectively. Due to the lack of standard material for air, direct assessment of the accuracy was not possible. This study was applied to the analysis of Seoul ambient air and their results are reported herein.

• 응용통계연구
• /
• 제2권1호
• /
• pp.48-53
• /
• 1989

본 연구에서는 t 분포 백분위점을 구하는 방법으로 표준정규분포의 백분위점을 이용하는 간접근사공식들과는 달리 p와 n만의 직접근사공식을 찾았다. Hoaglin이 $\chi^2$분포에 적용했던 탐색적분석과정을 거쳐서 찾아낸 이 공식은 그 형태가 간단하여 일상적인 자료분석에서 손쉽게 이용될 수 있을 뿐만 아니라 최대 상대오차가 1.2%밖에 되지않는 좋은 공식이다.

• 대한수학회지
• /
• 제35권4호
• /
• pp.903-931
• /
• 1998

Since the modular curves X(N) = $\Gamma$(N)\(equation omitted)＊ (N =1,2,3) have genus 0, we have field isomorphisms K(X(l))(equation omitted)C(J), K(X(2))(equation omitted)(λ) and K(X(3))(equation omitted)( $j_3$) where J, λ are the classical modular functions of level 1 and 2, and $j_3$ can be represented as the quotient of reduced Eisenstein series. When N = 4, we see from the genus formula that the curve X(4) is of genus 0 too. Thus the field K(X(4)) is a rational function field over C. We find such a field generator $j_4$(z) = x(z)/y(z) (x(z) = $\theta$$_3$((equation omitted)), y(z) = $\theta$$_4$((equation omitted)) Jacobi theta functions). We also investigate the structures of the spaces $M_{k}$($\Gamma$(4)), $S_{k}$($\Gamma$(4)), M(equation omitted)((equation omitted)(4)) and S(equation omitted)((equation omitted)(4)) in terms of x(z) and y(z). As its application, we apply the above results to quadratic forms.rms.

• 대한방사성의약품학회지
• /
• 제5권1호
• /
• pp.26-35
• /
• 2019

$^{188}Re$ is one of the most readily available generator derived and useful radionuclides for therapy emitting ${\beta}^-$ particles (2.12 MeV, 71.1% and 1.965 MeV, 25.6%) and imageable gammas (155 keV, 15.1%). The $^{188}W/^{188}Re$ generator is an ideal source for the long term (4-6 months) continuous availability of no carrier added (NCA) $^{188}Re$ suitable for the preparation of radiopharmaceuticals for radionuclide therapy. Rhenium-188 has been used for the preparation of therapeutic radiopharmaceuticals for the management of diseases such as bone metastasis, rheumatoid arthritis and primary cancers. Several early phase clinical studies using radiopharmaceuticals based on $^{188}Re$ -labeled phosphonates, antibodies, peptides, lipiodol and particulates have been reported. In this review, we addressed the current development status of $^{188}Re$ radiopharmaceuticals for liver cancer therapy and their applications.

• 대한전자공학회논문지SD
• /
• 제38권4호
• /
• pp.43-43
• /
• 2001

단열회로를 이용한 8-b×8-b 파이프라인 승산기와 4가지 위상을 가지는 전원클럭을 공급하기 위한 개선 된 구조의 전원클럭 발생기를 설계하였다. 전원클럭 신호선의 전하는 복원되어 에너지 소모를 줄인다. 단열회로는 ECRL 형태를 기본으로 하였으며 0.6㎛ CMOS 공정을 사용하여 설계하였다. 개선된 전원클럭 발생기는 기존회로보다 4∼11% 정도 효율이 높았다. 모의실험결과 제안하는 단열회로 승산기는 CMOS 승산기보다 2.6∼3.5배 정도의 에너지를 감소시켰다.

• 한국통신학회논문지
• /
• 제42권5호
• /
• pp.951-958
• /
• 2017

채널 재구성 기법이란 통신시스템에서 의도되지 않은 수신자가 수신 신호로부터 어떤 채널 부호가 사용되었는지, 주요 파라미터는 무엇인지를 알아내는 기법이다. 본 논문은 수신한 신호가 길쌈부호로 부호화된 경우, 사용된 길쌈부호의 주요파라미터인 입출력단의 비트수인 k와 n, 그리고 $k{\times}n$ 생성다항식행렬(Polynomial Generator Matrix, PGM)을 찾아내는 기법에 대해 다룬다. 본 논문은 M. Marazin 등이 제안한, 피버팅을 통한 가우스 조단소거법(Gauss Jordan Elimination Through Pivoting, GJETP)을 사용한 길쌈부호의 채널 재구성 기법에서 채널오류율과 무관하게 임계값을 설정해주던 것과 달리, 수신한 시퀀스로부터 2진 대칭 채널(Bynary Symetric Channel, BSC)의 채널오류확률을 추정하고 이로부터 임계값을 설정하는 방식을 제안하고, S. Shaojing 등의 연판정(soft decision) 값을 이용한 기법을 적용시켜서 채널 재구성 기법의 성공률을 향상시켰다.

• Korean Journal of Mathematics
• /
• 제21권4호
• /
• pp.365-374
• /
• 2013

Let $k=\mathbb{F}_q(T)$ be a rational function field over the finite field $\mathbb{F}_q$, where q is a power of an odd prime number, and $\mathbb{A}=\mathbb{F}_q[T]$. Let ${\gamma}$ be a generator of $\mathbb{F}^*_q$. Let $\mathcal{H}_n$ be the subset of $\mathbb{A}$ consisting of monic square-free polynomials of degree n. In this paper we obtain an asymptotic formula for the mean value of $L(1,{\chi}_{\gamma}{\small{D}})$ and calculate the average value of the ideal class number $h_{\gamma}\small{D}$ when the average is taken over $D{\in}\mathcal{H}_{2g+2}$.

• 한국염색가공학회지
• /
• 제7권2호
• /
• pp.55-62
• /
• 1995

Plasma polymerization of Perfiuoropropene(PFP) and n-Hexane was carried out in a tubular type reactor by means of 13.56MHz radio frequency generator at the fixed RF discharge power of 25W and at the pressures of 100mTorr, 140mTorr and 200mTorr. The thin films were deposited on PAN fabrics in order to improve the dimemsional stability of woven states in hot water laundry. IR spectroscopy was used for the analysis of the structures of the thin films deposited and SEM for examination of surfaces of the fabrics. the PAN fabrics, which were coated by thin films at several experimental conditions, were immersed in boiling water for 2 hours and then the dimension stability of woven states were evaluated. In spite of very thin films, the results of surface modification were satisfactory. In general the performace of thin films by PFP was superior to that of n-Hexane.