Development of Ferromagnetic Superspins in Bare Cu Nanoparticles by Electronic Charge Redistribution

We report on the results of investigating the ferromagnetic properties of bare Cu nanoparticles. Three sets of bare Cu nanoparticle assemblies with mean particle diameters of 6.6, 8.1, and 11.1 nm were fabricated, employing the gas condensation method. Curie-Weiss paramagnetic responses to a weak driving magnetic field were detected, showing the appearance of particle superspins that overcomes the diamagnetic responses from the inner core. The isothermal magnetization displays a Langevin field profile together with magnetic hysteresis appearing even at 300 K, demonstrating the existence of ferromagnetic superspins in the Cu nanoparticles. Shifting of a noticeable amount of electronic charge from being distributed near the lattice sites in bulk form toward their neighboring ions in nanoparticles was found. The extended 3d and 4s band mixture are the main sources for the development of localized 3d holes for the development of ferromagnetic particle superspins in Cu nanoparticles.     

荷移-紫外分光光度法测定硫酸庆大霉素含量

利用硫酸庆大霉素与四氯苯醌在水溶液中发生电荷转移反应,建立了简单快速测定硫酸庆大霉素含量的荷移紫外分光光度法。荷移络合物在波长342 nm处有最大吸收,该荷移衍生物的吸光度与硫酸庆大霉素浓度在0.1~3 mg/m 范围内吸光度和浓度呈现良好线性关系y=0.1652x+0.3054,R~2=0.9996,平均加样回收率为100.81%,RSD为2.55%。该方法简便、准确、重现性好,适用于硫酸庆大霉素的快速测定。     

分子内电荷转移荧光传感器的研究进展

荧光传感器提供了方便,快捷,廉价的分析检测重金属离子的方法,并且有很高的灵敏度和选择性.它在环境科学,分析化学以及生命科学等领域有着广泛的应用前景.综述了分子内电荷转移(intramolecular charge transfer)荧光传感器的最新研究进展,并展望了该领域的发展趋势.     

可逆加成-断裂链转移(RAFT)聚合的研究进展

自可逆加成-断裂链转移自由基聚合技术在1998年发明以来,就逐渐成为聚合研究者的一种非常强大的合成工具,并在研究与应用领域得到很快的发展。文章综述了可逆加成-断裂链转移聚合的RAFT试剂的分类、聚合机理及聚合中的阻滞现象,简要说明了RAFT技术应用的研究进展。     

线性聚能装药切割岩石的数值模拟

运用改进的MOCL程序,数值模拟了线性聚能装药金属射流的形成以及射流侵彻岩石的全过程,得到了锥角为60°的聚能装药结构爆轰产物膨胀、药型罩变形、射流形成过程及锥角为60°和90°时的射流速度梯变分布。不同时刻射流的分布显示,在拉伸过程中,锥角为60°的聚能射流速度变小,速度梯度较大,头部速度为4500m·s-1;锥角为90°的聚能射流,头部速度为3500m·s-1速度梯度较小,与实际物理过程相一致。结果表明,模拟结果基本符合聚能射流的物理现象和规律,说明采用的物理模型和数值算法是合理的。     

氮杂开链冠醚类似物

从分类,合成及应用等方面概述了近年来氮杂冠醚及其类假物的研究进展。     

Adsorption Isotherms for Intermediates Formed in Charge Transfer Processes

The adsorption of phenol in the form of phenoxy radicals on the surface of a bright Pt electrode is discussed. Two main features of the adsorption isotherm are brought out. The fractional coverage Θ changes suddenly at a characteristic potential, in a manner reminiscent of two dimensional phase formation. This is attributed to the existence of an isotherm with strong lateral attraction interaction forces. The corresponding two-dimensional equation of state resembles qualitatively the Van der Waals equation of state at temperatures below the critical temperature. For the potential dependence of adsorption a new type of isotherm is used which combines the effects of potential on charge-transfer equilibrium and on the solvent-solute replacement equilibrium on the surface of the electrode. The resulting function, describing the variation of Θ with E fits the observed inhibition effects of phenol on the rate of oxidation of Γ, and should also be taken into consideration in deriving Tafel slopes for different mechanisms.     

Intramolecular Charge Transfer Luminescence of a donorethylsubstituted pyridinium ion

The dimethoxyphenyl-ethyl-substituted pyridinium ion 1 shows a long-wave absorption and fluorescence, which are attributed to an intramolecular electron donor-acceptor complex. In contrast to electrically neutral complexes the fluorescence quantum yield of 1 in polar solvents is comparatively high and the radiative decay time is rather small. The excited complex can also be generated by electrochemical methods.     

长钢轨整体铺换车的研制和应用

长钢轨铺换车（简称换轨车）是长钢轨更换的主要设备,我段从1984年以来,就开始采用分体式换轨车更换长钢轨,为我局铺设无缝线路发挥了重要的作用。但是,分体式换轨车上下拖车,辅助时间较长,影响换轨进度;而且轨条在穿入龙口装置时,用压机顶起轨头,容易碰伤人员;特别是随着更换轨型的逐级增大和淬火轨的出现,在小半径曲线地段上换轨,由于车体自重小,容易掉道,起复难度很大。为此,研制新型的换轨车,改进技术性能,迫切需要。笔者针对分体式换轨车存在的问题,提出了相应的对策,构思出几种新型的换轨车方案,分析各自的优缺点,进行相互的比较,从中选择了桁架式整体换轨车方案进行设计与研制,通过实际应用,取得了良好的效果。     

可逆加成—断裂链转移自由基聚合研究

可逆加成-断裂链转移(Reversible addition-fragmentation chain transfer,RAFT)自由基聚合是最近发展起来的一种活性可控自由基聚合技术。该技术对聚合调控效果好、聚合条件相对温和、适用单体范围广等优点而备受关注,已成为一种有效的聚合物分子设计手段,文章介绍了RAFT聚合的机理、优点及应用。     

Effect of Ferrocene Position on Charge Transfer in ds-DNA Films

Ferrocene-labeled DNA systems where the Fc group is directly attached to deoxyuridine are investigated electrochemically in an effort to elucidate the electron transfer properties of these systems. The rigid linkage between the Fc group and the nucleobase provides control over the position of the Fc group within the ds-DNA and helps to elucidate the effect of the position of the redox label on the electrochemical behaviour of the ds-DNA films. Cyclic voltammetry, electrochemical surface plasmon resonance and scanning electrochemical microscopy measurements show that charge transfer (CT) in such systems is to a large extent controlled by the dynamic properties of surface-bound ds-DNA rather than by the CT through base-pair stacks.     

The Charge Transfer Photochemistry of Coordination Complexes in Aqueous Solution

Irradiation of charge transfer absorption bands of coordination complexes can result in net oxidation reduction or ligand exchange reactions. The photoredox processes generally involve the formation of reactive radicals in the primary photochemical act. The identification of these primary radicals is essential to the specification of the primary photochemical act since radical reactions with substrate, other radicals, etc. can make the net products and yields appear vastly different from the nature of the primary act. For example, in a few documented cases, the metal ion fragment formed in a photoredox process has characteristics of a radical and can couple with ligand radicals giving rise to a net photochemical process which appears to be ligand exchange rather than photoredox. A variety of radicals, organic as well as inorganic, can be generated and studied in aqueous solution. Some information has also been obtained concerning the nature of the photochemical precursors to the radicals formed in photoredox processes.     

分光光度法测定富马酸比索洛尔

基于药物和显色剂之间荷移反应,建立了一种对富马酸比索洛尔含量检测的分光光度法。在水介质中,富马酸比索洛尔与茜素红在室温中放置15min后形成1∶1型荷移配合物,其λmax为535nm,表观摩尔吸光系数为6.76×103L/(mol·cm),线性范围为10¹00mg/L,线性回归方程为A=0.085+0.00712c,相关系数r=0.99904,相对标准偏差RSD为0.44%(n=6)。将该方法用于富马酸比索洛尔片含量的测定,回收率为在98.3%100mg/L,线性回归方程为A=0.085+0.00712c,相关系数r=0.99904,相对标准偏差RSD为0.44%(n=6)。将该方法用于富马酸比索洛尔片含量的测定,回收率为在98.3%¹02.6%之间。     

荷移分光光度法测定交沙霉素片含量

在乙醇介质中,交沙霉素与百里酚蓝发生荷移反应,以试剂为参比,体系在440 nm处产生一个新的吸收峰。在最佳反应条件下,交沙霉素在0.0032~0.036 mg/m L范围内,A440nm与ρ之间存在较好的线性关系,回归方程为A440nm=19.246ρ(mg/m L)-0.031,相关系数为0.9993,检出限为0.0021 mg/m L。该法用于测定交沙霉素片中交沙霉素的测定,具有简单、快速,准确的特点,适用于交沙霉素片的质量控制。     

线性聚能装药对自锻弹丸干扰的数值模拟

为了研究线性聚能装药以不同角度干扰自锻弹丸的效果,采用有限元软件ANSYS/ls-dyna对线性聚能装药从不同角度(0°、30°、60°、90°)干扰自锻弹丸以及自锻弹丸被干扰后侵彻45号钢板的全过程进行数值模拟,然后运用Lsprepost后处理软件分析了自锻弹丸与聚能装药的射流头部在相遇前、相遇过程以及相遇后侵彻45号钢板过程中3个阶段的物理变化,通过分析对比自锻弹丸被干扰后的偏转距离、破碎程度、侵彻能力等确定了线性聚能装药干扰自锻弹丸的最佳干扰角度。结果表明,线性聚能装药可以对自锻弹丸进行有效的干扰,其干扰角度对干扰效果有较大影响。在0°~90°范围内,干扰角度为60°时干扰效果最佳。     

起爆方式对线性聚能装药射流形成的影响

以工程中常用的柔性切割器为研究对象,在不考虑端部效应的前提下,对3种起爆方式下线性聚能装药射流的形成过程进行了理论分析和数值模拟。结果表明,不同起爆方式下射流头部速度以端部面起爆最大,线起爆次之,端部点起爆在端面附近处形成的最低,但在距端面一定距离处,射流头部速度又能增大到与端部面起爆的速度相近。在射流内部,端部面起爆形成的射流在内部各点处的速度都是3种起爆方式中最大的,而端部点起爆时,则是随着距起爆点距离的增加由处处小于线起爆的射流速度分布转变到与端部面起爆相同的射流速度分布。在此基础上进一步提出3种起爆方式下线性聚能装药切割目标的数值模拟方法。     

Electrical Properties of Polymers Doped with Charge Transfer Complexes Forming Additives

Because of their good mechanical and processing properties as well as their low price, polymers have replaced such traditional materials as metal and wood in many fields of application. However, they lack one important characteristic-they do not conduct electricity. As with practically all organic substances known to date, they are usually good insulators; only a few categories can be classified as semiconductors. Materials which display higher conductivity can be obtained by synthesizing different polymers with a conjugated or aromatic backbone chain [1], but such materials, although classified as macromolecular, do not show the properties that would make polymers attractive from the point of view of application. Being poorly soluble, brittle, and melting at high temperatures, usually with decomposition, they are interesting practically only from the theoretical point of view.     

Kinetics of Light-Induced Intramolecular Charge Transfer and Proton Release in Bacteriorhodopsin

Recent advances in understanding the intramolecular charge transfer and proton release by the light-driven proton pump bacteriorhodopsin (bR) are critically reviewed. The focus is on the time-resolved electrical methods, i.e., photocurrent and photovoltage measurements, and on transient absorption experiments with pH-sensitive dyes. Particular attention is paid to the following topics: charge translocation in the low-pH forms of bR (acid-blue and acid-purple); electrogenicity of the 13-cis cycle; results with bR mutants; surface-bound dyes to detect the proton release at specific sites on either side of the protein; the question of kinetic coupling between the deprotonation of the Schiff base and proton release; and rapid long-range migration of protons along the surface of the purple membrane.