• Journal of the Institute of Electronics Engineers of Korea SC
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• v.46 no.2
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• pp.72-77
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• 2009

In this paper, a 3.2Gb/s clock and data recovery (CDR) circuit for a high-speed serial data communication without the reference clock is described This CDR circuit consists of 5 parts as Phase and frequency detector(PD and FD), multi-phase Voltage Controlled-Oscillator(VCO), Charge-pumps (CP) and external Loop-Filter(KF). It is adapted the PD and FD, which incorporates a half-rate bang-bang type oversampling PD and a half-rate FD that can improve pull-in range. The VCO consists of four fully differential delay cells with rail-to-rail current bias scheme that can increase the tuning range and tuning linearity. Each delay cell has output buffers as a full-swing generator and a duty-cycle mismatch compensation. This materialized CDR can achieve wide pull-in range without an extra reference clock and it can be also reduced chip area and power consumption effectively because there is no additional Phase Locked- Loop(PLL) for generating reference clock. The CDR circuit was designed for fabrication using 0.18um 1P6M CMOS process and total chip area excepted LF is $1{\times}1mm^2$. The pk-pk jitter of recovered clock is 26ps at 3.2Gb/s input data rate and total power consumes 63mW from 1.8V supply voltage according to simulation results. According to test result, the pk-pk jitter of recovered clock is 55ps at the same input data-rate and the reliable range of input data-rate is about from 2.4Gb/s to 3.4Gb/s.

• Journal of Environmental Science International
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• v.12 no.2
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• pp.201-205
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• 2003

The dechlorination of chlorinated methanes by iron powder and palladium coated iron (Pd/Fe) was studied in batch experiments. Iron powder dechlorinated carbon tetrachloride (CT) with a half-life of 4 days. Three chloromethane was found as major product and less chlorinated daughters. Mass balance found was to be about 93-99%. Pd/Fe showed very enhanced reactivity for CT in comparing with plain iron. The major dechlorination products of CT were also less chlorinated methanes with Pd/Fe. Pd/Fe also degrade the produced less chlorinated compounds. Sequential reactions were occurred on Pd/Fe. As the Pd/Fe content increased, the reaction rate was increased linearly.

• Journal of the Korean Mathematical Society
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• v.47 no.4
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• pp.789-804
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• 2010

We here investigate an existence and uniqueness of the nontrivial, nonnegative solution of a nonlinear ordinary differential equation: $$[\mid(w^m)]'\mid^{p-2}(w^m)']'\;+\;{\beta}rw'\;+\;{\alpha}w\;+\;(w^q)'\;=\;0$$ satisfying a specific decay rate: $lim_{r\rightarrow\infty}\;r^{\alpha/\beta}w(r)$ = 0 with $\alpha$ := (p - 1)/[pd-(m+1)(p-1)] and $\beta$:= [q-m(p-1)]/[pd-(m+1)(p-1)]. Here m(p-1) > 1 and m(p - 1) < q < (m+1)(p-1). Such a solution arises naturally when we study a very singular solution for a doubly degenerate equation with nonlinear convection: $$u_t\;=\;[\mid(u^m)_x\mid^{p-2}(u^m)_x]_x\;+\;(u^q)x$$ defined on the half line.

• Journal of IKEEE
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• v.10 no.1 s.18
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• pp.10-15
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• 2006

In this paper, a clock and data recovery (CDR) circuit for a serial link with a half rate 4x oversampling phase and frequency detector structure without a reference clock is described. The phase detector (PD) and frequency detector (FD)are designed by 4X oversampling method. The PD, which uses bang-bang method, finds the phase error by generating four up/down signal and the FD, which uses the rotational method, finds the frequency error by generating up/down signal made by the PD output. And the six signals of the PD and the FD control an amount of current that flows through the charge pump. The VCO composed of four differential buffer stages generates eight differential clocks. Proposed circuit is designed using the 0.18um CMOS technology and operating voltage is 1.8V. With a 4X oversampling PD and FD technique, tracking range of 24% at 3.125Gbps is achieved.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.2
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• pp.19-24
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• 2007

With recent advancement of high-speed, multi-gigabit data transmission capabilities, serial links have been more widely adopted in industry than parallel links. Since the parallel link design forces its transmitter to transmit both the data and the clock to the receiver at the same time, it leads to hardware's intricacy during high-speed data transmission, large power consumption, and high cost. Meanwhile, the serial links allows the transmitter to transmit data only with no synchronized clock information. For the purpose, clock and data recovery circuit becomes a very crucial key block. In this paper, a 5.4Gbps half-rate bang-bang CDR is designed for the applications of high-speed graphic DRAM interface. The CDR consists of a half-rate bang-bang phase detector, a current-mirror charge-pump, a 2nd-order loop filter, and a 4-stage differential ring-type VCO. The PD automatically retimes and demultiplexes the data, generating two 2.7Gb/s sequences. The proposed circuit is realized in 66㎚ CMOS process. With input pseudo-random bit sequences (PRBS) of $2^{13}-1$, the post-layout simulations show 10psRMS clock jitter and $40ps_{p-p}$ retimed data jitter characteristics, and also the power dissipation of 80mW from a single 1.8V supply.

• Journal of IKEEE
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• v.14 no.1
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• pp.40-46
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• 2010

This paper describes a clock and data recovery (CDR) circuit that supports dual data rates of 2.7Gbps and 1.62Gbps for DisplayPort standard. The proposed CDR has a dual mode voltage-controlled oscillator (VCO) that changes the operating frequency with a "Mode" switch control. The chip has been implemented using $0.18{\mu}m$ CMOS process. Measured results show the circuit exhibits peak-to-peak jitters of 37ps(@2.7Gbps) and 27ps(@1.62Gbps) in the recovered data. The power dissipation is 80mW at 2.7Gbps rate from a 1.8V supply.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.509-510
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• 2008

본 논문은 $0.18{\mu}m$ CMOS 공정을 사용하여 2.5Gb/s CMOS CDR을 설계하였다. CML type의 논리게이트를 이용하여 보다 높은 주파수의 대역의 데이터를 복원하기 위한 위상비교기(PD)와 PD의 up과 down신호를 지연없이 루프필터(LF)에 공급하기 위한 전하점프(CP) 그리고 외부 스위치를 통해 VCO이득을 조절할 수 있는 링 타입의 VCO로 구성되었다. 또한 VCO의 부담을 줄이기 위하여 half-rate 클럭 테크닉을 사용하였다. Cadence tool을 사용하여 모의실험 및 layout을 하였다. VCO이득은 100MHz/V이고, 클릭 jitter는 rising일 때 27ps, falling일 때 32ps로 우수한 결과를 얻을 수 있었다. 테스트칩 제작은 매그나침 $0.18{\um}$ CMOS 공정을 이용하였다. 칩 사이즈는 PAD를 포함하여 $850um{\times}750um$이다.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.7
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• pp.992-997
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• 2002

Two in vivo experiments were conducted to evaluate the effect of novel urease inhibitor hydroquinone (HQ) on ammonia release rate from urea hydrolysis, nitrogen balance, nutrient digestibility and efficiency of microbial protein synthesis. In Exp. 1, twelve crossbred cannulated lambs were randomly assigned within initial body weight block to one of four HQ treatments, which included 0 (control), 30, 60 or 80 mg HQ/kg DM intake. Ammonia concentration and pH of ruminal fluid were immediately measured at 0, 2, 4, 6 and 8 h after feeding. Increasing the dose of HQ tended (p<0.15) to linearly decrease NH3 formation. The ammonia peak concentration (2 h post-feeding) in animals receiving HQ was approximately one-half of that in animals not receiving HQ (p<0.01), and a relatively sustained ammonia release could be obtained at the dose of 30 or 60 mg HQ/kg DM. In Exp. 2, sixteen intact crossbred lambs (weight $40{\pm}0.8kg$) were used in a $2{\times}2$ factorial design experiment. The four rations consisting of soybean meal-based (SBM) or urea-based (Urea) nitrogen source with or without HQ (S1, S0, U1 and U0) were fed in digestion and N balance trials. Apparent digestibility of major nutrients except that of ADF was not affected by either nitrogen source or addition of HQ. Regardless of nitrogen source, supplementation of HQ significantly improved ADF digestibility (p<0.05). The various ration had no effects on N metabolism in the presence of HQ. There was significant difference between total purine derivatives (PD), estimated efficiency of microbial N synthesis (p<0.05) and urea-N excretion (p<0.01) in the urine for the SBM ration and for the Urea ration. However, HQ had little influence on efficiency of microbial N synthesis as proportion of daily intake of total tract digestible OM (p>0.05). No interactions between main nitrogen source and HQ were measured throughout the trial. Results of this study suggest that addition of HQ to ration may improve ADF digestion with having no negative effect on N metabolism and microbial protein production.

• The Korean Journal of Pharmacology
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• v.31 no.2
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• pp.251-259
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• 1995

Pharmacokinetics and pharmacodynamics of metoprolol, a selective beta-l blocker, were examined for 360 minutes after intravenous bolus administration of metoprolol to 6 dogs. Plasma concentration and excreted amount in the urine metoprolol were measured by liquid chromatography with fluorescence detection. PR interval and heart rate were measured by ECG monitoring. Blood pressure was monitored through intraarterial catheter in femoral artery and cardiac output by thermodilution method using Swan-Ganz catheter. To analyze the effect site concentration-response relationship, plasma concentration and pharmacological effects were simultaneously fitted to a two pharmacokinetic compartment linked to pharmacodynamic model with NONLIN program. Results are as follows. 1) The plasma concentration of metoprolol after intrvenous injection decreased biexponentially. The terminal half-life estimated was $1.33{\pm}0.40$ hours and the volume of distribution at steady state (Vdss) and the total body clearance were $1.04{\pm}0.4\;L/kg,\;6.55{\pm}2.21\;L/hr$, respectively. The central compartment volume of distribution and peripheral compartment volume of distribution were $0.35{\pm}0.14L/kg\;and\;0.69{\pm}0.34L/kg$. The renal clearance and intercompartment clearance were $0.53{\pm}0.25\;L/min\;and\;0.35{\pm}0.19\;L/min$. 2) Simulated biophase concentration-response curve shows hyperbolic relationship and the estimated concentration-effect relationship was best explained by Emax model when the prolongation of PR interval and the reduction of the heart rate were used as pharmacodynamic parameters. Emax and EC50 were estimated to be $26.3{\pm}4.7\;msec\;and\;88.8{\pm}82.3\;g/ml$ for PR interval, and $48.7{\pm}18.8\;beats/min\;and\;113.5{\pm}78.7\;ng/ml$ for heart rate, respectively. 3) The changes of cardiac output-effect site concentration relationship was best fitted by a linear model and the slope of the relationship was $0.005{\pm}0.003$. Diastolic blood pressure-effect site concentration relationship was also explained by the linear model and the slope of the relationship was $0.038{\pm}0.034$.