Feasible schemes for preparing all five-photon graph states

We propose feasible experimental schemes for preparing all five-photon graph states. Our schemes require only linear optical elements, photon detectors and post-selection, which are available in current experiment so that these schemes are within the reach of the current technology.     

特征荧光光谱法定量检测水质的研究

讨论了一种可同时检测自然水体中有机物和叶绿素a含量的快速分析方法。以武汉东湖水为样品,采用激光诱导荧光(LIF)的方法测量了水体的总荧光光谱(TLS);并用特征光谱荧光标记(SFS)技术对水体中溶解的有机物(DOM)及叶绿素a (Chl-a)的荧光光谱特征进行了分析和指认。并利用水的拉曼散射信号强度进行归一化的方法,分别得到较低浓度腐殖酸和叶绿素a的特征光谱归一化荧光强度以及它们在水体中浓度的标定曲线和线性关系式。另外, 对于较高浓度的腐殖酸溶液,确定了其特征光谱的荧光强度与浓度之间满足的函数关系。结果表明,在一定的浓度范围内,特征光谱的荧光强度与浓度之间仍然有很好的线性关系。该方法在自然水体质量的检测方面有广泛的应用前景,它能快速识别水体中的污染物,定量测量它们在水体中的含量,实现对自然水体的质量状况进行大范围的实时动态监测。     

壁画空鼓病害的探地雷达正演模拟检测

通常西藏壁画地仗层的厚度不足10cm,有效去除直耦杂波是利用高频探地雷达识别壁画空鼓病害的关键,在此基础上计算空鼓的厚度。模拟制作西藏壁画地仗,在其内部预设深度和厚度各不相同的规则空鼓,通过正演模拟试验确定探地雷达的采集参数,积累数据处理的经验,并比较不同雷达天线的性能。结果表明,针对RAMAC探地雷达和Ground Vision数据采集、后处理软件,时窗深度宜为3ns左右,采样频率应不低于142GHz,效果最明显的两个滤波器是带通滤波和抽取均道。当雷达天线与细泥层地仗耦合较好时,中心频率1.6GHz和2.3GHz的雷达天线均能准确检测出深3cm左右、厚约2cm的空鼓,1.6GHz天线的极限垂直分辨率约0.5 cm。     

柱前衍生高效液相色谱法测定食物中氨基酸含量

采用柱前衍生高效液相色谱法,测定了食物中天冬氨酸、赖氨酸、亮氨酸等１６种氨基酸含量。衍生试剂为６－氨基喹啉基－Ｎ－羟基玻珀酰亚氨基甲酸酯（ＡＱＣ）,流动相为磷酸盐与峰面积呈良好的线性关系,相关系数均在０．９９以上,回收率在８８％～１１０％之间,样品测定结果良好。     

非自治混沌系统的脉冲同步

研究两个非自治混沌系统之间的脉冲同步的实用稳定性,将问题转化为同步误差系统的原点的实用稳定性．利用脉冲微分方程的相关理论,给出了同步误差系统原点实用稳定的相关判据,并给出了误差范围的理论表达式．计算机仿真实验的结果验证了理论结果 关键词：     

Development of 1.3GHz high-T-c rf SQUID

A new high-T_c (HT_c) rf SQUID working at around 1.3GHz has been developed to avoid electromagnetic interference such as growing mobile communication jamming. This new system works in a frequency range from 1.23 to 1.42GHz (centred at 1.3GHz), which is not occupied by commercial communication. The sensor used in the 1.3GHz rf SQUID is made of a HT_c coplanar superconducting resonator and a large-area HT_c superconducting film concentrator. We have achieved in the 1.3GHz HT_c rf SQUID system a minimal flux noise of 2.5×10^{-5}Φ_0/\sqrt{Hz} and a magnetic field sensitivity of 38fT/\sqrt{Hz} in white noise range, respectively. The effective area of the concentrator fabricated on a 15×15mm^2 substrate is 1.35mm^2. It is shown that the 1.3GHz rf SQUID system has a high field sensitivity. Design and implementation of 1.3GHz HT_c rf SQUID offers a promising direction of rf SQUID development for higher working frequency ranges.     

准一维介观铝超导线的电阻振荡

介观铝超导线的特性近来被广泛研究,有关反常微分电阻的实验和理论研究工作都取得了不小的进展。特别是此前报道的在附加射频信号时,介观铝超导线出现的电阻－温度曲线的振荡现象尤为引人注目。我们通过电子束刻蚀法制作了准一维介观铝线。我们在没有附加任何条件下,观测到正常态（N）和超导态（S）转变温度附近电阻－温度曲线在小测量电流时出现振荡。这种振荡的产生可能是由于电压探头之间铝线中的N／S界面的数目随温度变化造成的。     

一种铂网栅薄层光谱电化学池的制作及表征

以铂网栅电极作工作电极,设计制作了一种应用于紫外-可见光谱电化学研究的新型光透薄层电化学池（OTTLE）,并以铁氰化钾-亚铁氰化钾体系对此光谱化学池进行了表征。铁氰化钾-亚铁氰化钾体系在该池中有良好的循环伏安特性,并可获得良好的紫外-可见光谱。测得的克式量电位E^0,电子转移数n与文献结果一致。     

Erratum to “Accurate determination of film thickness by low-angle x-ray reflection”

Equation (6) in Chin. Phys. 09 0833 (2000) is corrected. All subsequent derivations were given based on the correct Eq. (6), so the conclusions in the paper are not affected by the errata.