同步时序电路的波形图分析

本文通过实例提出同步时序电路的波形图分析方法,并且用实验观察波形加以验证。     

维持阻塞触发器设计原理新解

本文分析了由门级组成的两类锁存器, 并证明了传统的维持阻塞触发器即为由其中单轨输入锁存器设计的主从触发器.由于两个由时钟控制的与非门被主从两部分公用, 因此它的结构特别简单     

广州西村窑彩绘瓷无损分析检测

利用微聚焦X射线荧光探针与拉曼光谱仪2种方法,对西村窑彩绘瓷进行了系统的分析测试,结果表明西村窑彩绘瓷胎料选择了一种高质量的高岭土,瓷釉中氧化磷的含量远高于相应的瓷胎,暗示瓷釉中添加了草木灰作为助熔剂;瓷器彩绘的显色物相为赤铁矿(α-Fe2O3),彩绘的不同颜色主要与其中氧化铁含量有关,彩绘表面条状物经鉴定为钙长石(CaAl2Si2O8)。     

Vibrational characterization of L‐valine phosphonate dipeptides: FT‐IR,FT‐RS,and SERS spectroscopy studies and DFT calculations

Four L ‐valine (L ‐Val) phosphonate dipeptides that are potent inhibitors of zinc metalloproteases, namely, L ‐Val‐C(Me)₂‐PO₃H₂ (V1), L ‐Val‐CH(iP)‐PO₃H₂ (V2), L ‐Val‐CH(iB)‐PO₃H₂ (V3), and L ‐Val‐C(Me)(iP)‐PO₃H₂ (V4), are studied by Fourier‐transform infrared (FT‐IR) spectroscopy, Fourier‐transform Raman spectroscopy (FT‐RS), and surface‐enhanced Raman scattering (SERS). The band assignment (wavenumbers and intensities) is made based on (B3LYP/6‐311 + + G**) calculations. Comparison of theoretical FT‐IR and FT‐RS spectra with those of SERS allows to obtain information on the orientation of these dipeptides as well as specific‐competitive interactions of their functionalities with the silver substrate. More specifically, V1 and V4 appear to interact with the silver substrate mainly via a  C_sgCH₃ moiety localized at the  N_amideC_sg(CH₃)P molecular fragment. In addition, the  POH and isopropyl units of V4 assist in the adsorption process of this molecule. In contrast, the  C_αNH₂ and  PO₃H⁻ groups of V2 and V3 interact with the silver nanoparticles, whereas their isopropyl and isobutyl fragments seem to be repelled by the silver substrate (except for the  CH₂  of V3), similar to the  C_β(CH₃)₂ fragment of L ‐Val for all L ‐Val phosphonate dipeptides investigated in this work. The adsorption mechanism of these molecules onto the colloidal silver surface is also affected by amide bond behavior. Copyright © 2010 John Wiley & Sons, Ltd.     

Analysis of the influence of backscattered optical power over bidirectional PON links

Our aim is to describe the behavior of non-linear scattering effects that arise in standard single mode fiber (SMF), specifically scattering effects that propagate optical power in the reverse direction of the source signal such as Rayleigh Scattering (RS) and Brillouin Scattering (BS). For this purpose, the effects of backscattering phenomena over a bidirectional data transmission in a passive optical network (PON) scheme have been assessed. The impact of these high optical power components over reception at the optical line terminal (OLT) side has been determined when both links use the same wavelength. Bit Error Rate (BER) measurements have been performed with different transmission rates, using several techniques to mitigate the influence of backscattering over the received signal and considering cases with filtered and unfiltered BS.     

计算机网络通信中实时差错控制技术

在研究差错控制技术的基础上，使用查找表方法实现RS(里德索洛蒙)纠错码的编码和解码，并且模拟实现了FEC(前向纠错)和FEC／ARQ(重传反馈)两种实时差错控制系统．基于查找表方法的RS编解码方法能够提高编码／解码效率，减少通信中的延时；实验结果也验证了基于RS纠错码的FEC和FEC／ARQ实时差错控制方式能有效地恢复丢失的数据包，其丢包率可降低5％以上，从而提高了数据传输的可靠性，具有很好的实时性．     

Investigation of RS spectra of crystalline potassium perchlorate

The processes of molecular relaxation in crystalline potassium perchlorate are investigated by the method of RS spectroscopy in the field of totally symmetrical oscillation v₁(A) of the amen ClO ₄ ⁻ . The parameters of reorientation in relation to the polarized RS lines are evaluated from the temperature dependences of line widths. It is established that in KClO₄ the reorientation represents the activation process. Time correlation functions are obtained and the times of vibrational and orientational relaxation are determined, which show that with an increase in temperature the contribution of homogeneous broadening increases while that of the inhomogeneous one remains practically unchanged. Kh. I. Amirkhanov Institute of Physics at the Dagestan Center of the Russian National Academy of Sciences, 26 Bakinskikh Komissarov St., 94, Makhach-Kala, 367003. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 6, pp. 932–935, November–December, 1998.     

Vibrational and reorientational dynamics,crystal structure and solid–solid phase transition studies in [Ca(H2O)6]Cl2 supported by theoretical (DFT) calculations

[Ca(H₂O)₆]Cl₂ between 93 and 300 K possesses two solid phases. One phase transition (PT) of the first‐order type at = 218.0 K (on heating) and = 208.0 K (on cooling) was determined by differential scanning calorimetry. Thermal hysteresis of this PT (10 K), as well as the heat flow anomaly sharpness, suggests that the detected PT is a first‐order one. The entropy change value [ΔS ≈ 8.5 J mol⁻¹ K⁻¹ ≈ Rln(2.8)] associated with the observed PT suggests a moderate degree of molecular dynamical disorder of the high‐temperature phase. The temperature dependencies of the full width at half maximum values of the infrared band are due to ρ(H₂O)A₂ mode (at 205 cm⁻¹), and two Raman bands are arising from τ(H₂O)E and τ(H₂O)A₁ modes (at ca. 410 and 682 cm⁻¹, respectively), suggesting that the observed PT is associated with a sudden change of speed of the H₂O reorientational motions. The estimated mean value of activation energy for the reorientation of the H₂O ligands in the high‐temperature phase is ca. 11.4 kJ mol⁻¹ from Raman spectroscopy and 11.9 kJ mol⁻¹ from infrared spectroscopy. X‐ray single‐crystal diffraction measurement and spectroscopic studies (infrared, Raman and inelastic neutron scattering) also confirm that [Ca(H₂O)₆]Cl₂ includes two sets of differently bonded H₂O molecules. Ab initio calculations of the complete unit cell of one molecule of calcium chloride with a different number of water molecules (2, 4 and 6) have also been carried out. A comparison of Fourier Transform Infrared (FT‐IR), Fourier Transform Raman Scattering (FT‐RS) and inelastic neutron scattering spectroscopies results with periodic density functional theory calculations was used to provide a complete assignment of the vibrational spectra of [Ca(H₂O)₆]Cl₂. Copyright © 2016 John Wiley & Sons, Ltd.     

Evaluation of drug-polymer interaction in polymeric microspheres containing diltiazem hydrochloride

The aim of this study was to evaluate the drug-polymer interaction in polymeric microsphere formulations containing diltiazem hydrochloride (DH). The microspheres were successfully prepared by solvent evaporation technique using two different polymer types, Eudragit®RS 100 and ethylcellulose. The existence of a possible interaction between DH and the polymers was investigated by using DSC and XRD. The DSC curves and XRD patterns indicated that there was no interaction between DH and the polymers. The peak area calculations in the DSC curves of F1- and F2-coded microsphere formulations showed that DH was dispersed, not dissolved, in the ethylcellulose polymer matrix, while it partly dissolved in the Eudragit®RS 100 polymer matrix.     

含氨基酸席夫碱的5-氟尿嘧啶类衍生物的合成及Raman光谱分析

以N1-(2-四氢呋喃烷基)-5-氟尿嘧啶为原料,合成了三种含氨基酸席夫碱的5-氟尿嘧啶类衍生物,用元素分析,1HNMR表征了它们的结构。用拉曼光谱(RS)和表面增强拉曼光谱(SERS)分析了目标化合物的分子振动形式,比较它们在RS和SERS中的异同点。