• JSTS:Journal of Semiconductor Technology and Science
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• 제14권1호
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• pp.131-137
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• 2014

A 120 GHz voltage controlled oscillator (VCO) with a divider chain including an injection locked frequency divider (ILFD) and six static frequency dividers is demonstrated using 65-nm CMOS technology. The VCO is designed based on the LC cross-coupled push-push structure and operates around 120 GHz. The 60 GHz ILFD at the first stage of the frequency divider chain is based on a similar topology as the core of the VCO to ensure the frequency alignment between the two circuit blocks. The static divider chain is composed of D-flip flops, providing a 64 division ratio. The entire circuit consumes a DC power of 68.5 mW with the chip size of $1385{\times}835{\mu}m^2$.

• Archives of Pharmacal Research
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• 제23권3호
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• pp.206-210
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• 2000

A new series of phosphonate side chain analogues of 1$\alpha$,25-dihydroxyvitamin $D_3$ (1) have been synthesized. Antiproliferative activities of theses analogues (8a,b and 9a,b) using human keratinocyte cell shows that analogues which have natural A-ring show higher activity than unnatural A-ring series and almost equally active to 1 $\alpha$,25-Dihydroxyvitamin $D_3$(1) at 1 $\mu$M level.

• ETRI Journal
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• 제41권4호
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• pp.536-548
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• 2019

In this study, an electronically steerable parasitic array radiator (ESPAR) antenna via analog radio frequency (RF) switches for a single RF chain MIMO system is presented. The proposed antenna elements are spaced at ${\lambda}/64$, and the antenna size is miniaturized via a dielectric radome. The optimum reactance load value is calculated via the beamforming load search algorithm. A switch simplifies the design and implementation of the reactance loads and does not require additional complex antenna matching circuits. The measured impedance bandwidth of the proposed ESPAR antenna is 1,500 MHz (1.75 GHz-3.25 GHz). The proposed antenna exhibits a beam pattern that is reconfigurable at 2.48 GHz due to changes in the reactance value, and the measured peak antenna gain is 4.8 dBi. The reception performance is measured by using a $4{\times}4$ BPSK signal. The measured average SNR is 17 dB when using the proposed ESPAR antenna as a transmitter, and the average SNR is 16.7 dB when using a four-conventional monopole antenna.

• Elastomers and Composites
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• 제57권1호
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• pp.13-19
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• 2022

Polycarbonate diol-based waterborne polyurethane (WPU) was prepared by prepolymer mixing process. The prepolymer mixture contained the polycarbonate diol, isophorone diisocyanate (IPDI), dimethylol propionic acid, triethylamine, and ethylenediamine (EDA). The NCO/OH ratio in the prepolymer was adjusted by controlling the molar ratio of IPDI, and its effects on the properties of WPU were studied. The structure of WPU was characterized by fourier transform infrared spectroscopy. The average particle size increased and viscosity decreased with increasing NCO/OH ratio and EDA content in WPU. The reduced phase separation between soft and hard segments increased glass transition temperature. The reduction in the thermal decomposition temperature could be attributed to the low bond energy of urethane and urea groups, which constituted the hard segment. Additionally, the polyurethane chain mobility was restricted, elongation decreased, and tensile strength increased. The hydrogen bond between the hard segments formed a dense structure that hindered water absorption.

• 약학회지
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• 제38권2호
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• pp.202-210
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• 1994

To investigate the feasibility of mucosal delivery of $[D-Ala^6]$ LHRH, a potent analogue of LHRH, enzymatic proteolysis of $[D-Ala^6]$ LHRH and inhibitory effect of medium chain fatty acid salts(MFA) were studied using rabbit mucosal homogenate. $[D-Ala^6]$ LHRH incubated in homogenates of rectal(RE), nasal(NA) and vaginal(VA) mucosa were assayed by HPLC. The degradation of $[D-Ala^6]$ LHRH followed the first order kinetics. The degradation products were found as $[D-Ala^6]$ $LHRH^{1-7}$(m-i), to a lesser extent, $[D-Ala^6]$ $LHRH^{1-9}$(m-ii) and $[D-Ala^6]$ $LHRH^{1-3}$(m-iii) by the method of amino acid analysis(PITC method). The formation of$[D-Ala^6]$ $LHRH^{1-7}$ was not inhibited by the addition of disodium ethylenediaminetetraacetic acid but inhibited by sodium tauro-24,25-dihydrofusidate, suggesting that endopeptidase 24.11(EP 24.11) cleaves the $Leu^7-Arg^8$ bond of $[D-Ala^6]$ LHRH and is the primary $[D-Ala^6]$ LHRH degrading enzyme. The patterns of $[D-Ala^6]$ LHRH degradation indicated that EP 24.11 exists in each mucosal homogenate with the order of RE>NA>VA. MFA significantly inhibited the proteolysis of $[D-Ala^6]$ LHRH. The addition of sodium caprate(1.0%) or sodium laurate(0.5%) to the each mucosal homogenate completely protected $[D-Ala^6]$ LHRH from the degradation.

• Bulletin of the Korean Chemical Society
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• 제24권11호
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• pp.1590-1598
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• 2003

In this paper we have presented the results for viscosity and self-diffusion constants of model systems for four liquid n-alkanes ($C_{12}, C_{20}, C_{32}, and C_{44}$) in a canonical ensemble at several temperatures using molecular dynamics (MD) simulations. The small chains of these n-alkanes are clearly $<{R_{ee}}^2>/6<{R_g}^2>>1$, which leads to the conclusion that the liquid n-alkanes over the whole temperatures considered are far away from the Rouse regime. Calculated viscosity ${\eta}$ and self-diffusion constants D are comparable with experimental results and the temperature dependence of both ${\eta}$ and D is suitably described by the Arrhenius plot. The behavior of both activation energies, $E_{\eta}$ and $E_D$, with increasing chain length indicates that the activation energies approach asymptotic values as n increases to the higher value, which is experimentally observed. Two calculated monomeric friction constants ${\zeta}$ and ${\zeta}_D$ give a correct qualitative trend: decrease with increasing temperature and increase with increasing chain length n. Comparison of the time auto-correlation functions of the end-to-end vector calculated from the Rouse model for n-dodecane ($C_{12}$) at 273 K and for n-tetratetracontane ($C_{44}$) at 473 K with those extracted directly from our MD simulations confirms that the short chain n-alkanes considered in this study are far away from the Rouse regime.

• 한국축산식품학회지
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• 제21권4호
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• pp.367-373
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• 2001

MFGM 당단백질의 하나인 PAS-7을 GPC 및 affinity chromatography에 의해 정제하여 2-AB로 형광 표식한 후, anion-exchange column 및 reversed-phase column을 이용해 5개의 성분을 분리하였다. 그 중 가장 상대량이 많은 성분 e에 대하여 RAAM2000을 이용한 당쇄구조 해석을 실시하여, 성분 e는 RAAM2000 GPC에 의하여 4개의 성분으로 분리되어 각각 calibration standard 12.10, 8.88, 5.84 및 4.86GU의 용출위치에 검출되었다. 이 용출위치와 당쇄구조는 livrary의 component-7457과 일치하며, 12.2GU의 크기로 분자량은 1788로 판단되며 library의 당쇄와 약 85%의 확률로 일치했다. 그 결과 성분 e의 당쇄구조는 환원말단에 $\alpha$1-6결합된 fucose를 1개 함유하며, core부분의 비환원말단에 N-acetyllactosamine branch를 2개 함유한 전형적인 biantennary 당쇄구조인 것으로 추축되어, 이전 HPLC, acetolysis, sequential exoglycosidase 소화, NMR분석에 의해 보고된 성분 7N1A의 구조와 일치함으로써, OGS RAAM2000을 이용한 PAS-7의 당쇄구조 해석의 유용성이 증명되었다.

• 대한전자공학회논문지
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• 제24권1호
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• pp.10-14
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• 1987

Considering transition gating of the input unipolar NRZ signal, the equivalent linear time-invariant model has been derived for the PLL in the timing clock recovery circuits. The magnitude of the alignment and accumulated jitter has been found along a chain of repeaters. For the timing recovery circuit of 90 Mbps optical communication system, the computer simulation shows that, for the first stage of the chain, the alignment jiter and the accumulated jitter are of -5.1766 dB and for the 7-th stage, the alignment jitter and accumulated jitter have the value of -1.0193dB, 4.9053 dB respectively.

• 정보보호학회논문지
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• 제12권2호
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• pp.21-34
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• 2002

본 논문에서는 최근 발표된 멱승방법인 나눗셈 체인을 적용한 새로운 모듈로 멱승기의 하드웨어 구조를 제안하였다. 나눗셈 체인은 제수(divisor) d=2 또는 $d=2^I +1$ 과 그에 따른 나머지(remainder) r을 이용하여 지수 I를 새롭게 변형하는 방법으로 전체 멱승 연산이 평균 약 1.4$log_2$E 번의 곱셈으로 가능한 알고리즘이다. 이것은 Binary Method가 하드웨어 구현 시 항상 worst case인 $2log_2$E의 계산량이 필요한 것과 비교할 때 상당한 성능개선을 의미한다. 전체 구조는 파이프라인 동작이 가능한 선형 시스톨릭 어레이 구조로 설계하였으며, DG(Dependence Graph)를 수평으로 매핑하여 k비트의 키 사이즈에 대해 두 개의 k 비트 프레임이 k/2+3 개의 PE(Processing Element)로 구성된 두 개의 곱셈기 모듈을 통해 병렬로 동시에 처리되어 100% 처리율을 이루게 하였다. 또한, 규칙적인 데이터 패스를 가질 수 있도록 나눗셈체인을 새롭게 코딩하는 방법을 제안하였다. ASIC 구현을 위해 삼성 0.5um CMOS 스탠다드 셀 라이브러리를 이용해 합성한 결과 최장 지연 패스는 4.24ns로 200MHz의 클럭이 가능하며, 1024비트 데이터 프레임에 대해 약 140kbps의 처리속도를 나타낸다. 복호화 시에는 CRT(Chinese Remainder Theorem)를 적용하여 처리속도를 560kbps로 향상시켰다. 전자서명의 검증과정으로 사용되기도 하는 암호화 과정을 수행할 때 공개키 E는 3,17 혹은 $2^{16} +1$의 사용이 권장된다는 점을 이용하여 E를 17 비트로 제한할 경우 7.3Mbps의 빠른 처리속도를 가질 수 있다.

• Bulletin of the Korean Chemical Society
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• 제7권5호
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• pp.367-371
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• 1986

Dynamic and equilibrium properties of n-alkane chains immersed in solvent molecules have been investigated by a molecular dynamics method. The n-alkane chain is assumed to be a chain of elements (CH$_2$) interconnected by bonds having a fixed bond length and bond angle, but each bond of the chain is allowed to execute hindered internal rotation. We studied the effect of the number of the chain elements (N$_c$ = 10, 15 and 20) on the equilibrium properties of the system, e.g., the pair correlation functions between a chain element and solvent molecules, g$_{cs}$(r), and between the chain elements, g$_{cc}$(r), and the configurational properties such as the mean-square end-to-end distance < R$^2$ >, the mean-square radius of gyration < S$^2$ >, and the eigenvalues of the moment-of-inertia tensor < S$_i^2$ > / < S$^2$ > (i = 1, 2 and 3). We also studied the dynamic properties of the system, e.g., the autocorrelation function C(A;t) where A = R$^2$(t), = S$^2$(t), or = ${\vec{V}}(t)({\vec{V}}$ = velocity of the center of mass), and the diffusion coefficient D. The g$_{cs}$(r)'s are almost equal irrespective of the change of Nc while g$_{cc}$(r) becomes larger as N$_c$ increases; The MD computed configurational properties < R$^2$2 > and < S$^2$ > were found to be a little different from the values calculated from the statistical equations of < R$^2$ > and < S$^2$ >, it may be due to the fact that our model for the MD simulations includes a long-range volume effect. From the < S$_i^2$ > / < S$^2$ >, it is found that the chain molecule has a nearly spherical shape irrespective of the variation of N$_c$. For the dynamic properties we found that the C(R$^2$;t) and C(S$^2$;t) of lower N$_c$ decay faster than those of higher N$_c$, while the C($\vec V$;t) of the center of mass in the chain is weakly dependent on the N$_c$. The center of mass diffusion coefficient D$_c$ decreases as N$_c$ increases while the end point diffusion coefficient D$_e$ is nearly equal irrespective of the change of N$_c$.