默默奉献的珠坛耕耘者——记珠算专家张福汉

历史如镜,传统如河。珠算事业本是一条长河,珠算工作者犹如那相守不弃的桥,河水长流不息,真正热爱并奉献那河的,莫过这坚守始终的桥了。生活中,"缘"经常被用来解释人与人、人与事的某种说不清、道不明的必然联系。而这种必然性又常常带有很大的偶然性,令人匪夷所思。解答张福汉先生与珠算事业的关系又一次用到了这个字。可是,张福汉四十余年与珠算教育、珠算研究的关系,又怎是一个"缘"字了得。     

Preparation of high performance thin-film polarizers

<正>The optical performance of thin film polarizers is highly sensitive to the layer thicknesses of thin film.The thicknesses of the sensitive layers are optimized in order to gain broader polarizing zone in such case when the total layer thickness does not increase.An automatic layer thickness control system is established,and errors caused by different monitoring methods are analyzed.With this thickness control system,thin-film polarizers with T_p higher than 98%and T_p/T_s higher than 200:1(T_p and T_s are transmissions for p- and s-polarizations,respectively) with the bandwidth of 11 nm are prepared.Using the system allows for optimum repeatability of three successive runs.     

Teleportation Capability of Six-Qubit Cluster State

Recently Wei-Bo Gao et al. [Phys. Rev. Lett. 104 （2010） 020501]; reported on the creation of a 4-photon 6-qubit cluster state. It is shown this states can be utilized for perfect teleportation of arbitrary three qubit systems and controlled teleportation of an arbitrary two-qubit state. Therefore, the six-qubit cluster state as quantum channels is equivalent to that of maximally six-qubit entangled state.     

气相色谱-质谱法分析树苔浸膏的成分

采用分子蒸馏法对树苔浸膏进行分级分离,用气相色谱-质谱法对各级馏分进行定性和定量分析。结果表明:三级馏分共鉴定出55种成分,主要成分是苔黑酚单甲醚、分歧扁枝衣素单甲醚、扁枝衣酸乙酯、柔扁枝衣酸甲酯、β-苔黑酚羧酸甲酯、赤星衣酸乙酯、苔黑酚羧酸乙酯、柔扁枝衣酸乙酯、棕榈酸乙酯、油酸乙酯、亚麻酸乙酯和亚油酸乙酯。     

Air-breathing mode laser propulsion with a long-pulse TE CO_2 laser

Air-breathing mode laser propulsion experiment with a long-pulse transversely excited(TE) CO2 laser is carried out,and its ignition problem is solved with the ignition needle of lightcraft.Owing to the ignition needle,an order of magnitude reduction in the ignition threshold is demonstrated.The result is compared with previous study.The momentum coupling coefficient is also measured in the experiment and its dependence upon laser pulse energy(6-14 J) and pulse width(20,32,and 40μs) is discussed.     

Fabrication of high-quality submicron Nb/Al--AlOx/Nb tunnel junctions

Nb/Al-AlOx/Nb tunnel junctions are often used in the studies of macroscopic quantum phenomena and superconducting qubit applications of the Josephson devices. In this work, we describe a convenient and reliable process using electron beam lithography for the fabrication of high-quality, submicron-sized Nb/Al-AlOx/Nb Josephson junctions. The technique follows the well-known selective Nb etching process and produces high-quality junctions with Vm=100 mV at 2.3 K for the typical critical current density of 2.2 kA/cm^2, which can be adjusted by controlling the oxygen pressure and oxidation time during the formation of the tunnelling barrier. We present the results of the temperature dependence of the sub-gap current and in-plane magnetic-field dependence of the critical current, and compare them with the theoretical predictions.     

一类捕食-被食系统的全局渐近稳定性

本文对如下形式的具分布时滞的捕食－被食系统：通过构造Ｌｉａｐｕｎｏｖ泛函,得到了该系统正平衡解全局渐近稳定的充分条件,所得结果包括了一些相关的已有结果为其特例。     

Gd掺杂对Bi2Sr2Ca1-xGdxCu2Oy单晶载流子浓度和各向异性电阻率的影响

系统地研究了Gd掺杂对Bi2Sr2Ca1-xGdxCu2Oy单晶超导电性及各向异性电阻率的影响.Tc满足Tc/Tc,max=1-82.6(ax+b)2,并随Gd含量的增加而下降,这是由于Gd掺杂引起载流子浓度减小所导致.在x≥0.19时,ρab(T)在Tc附近有类半导体行为,dρab/dT随Gd含量增大而增大.ρc(T)呈半导体行为,并可用唯象公式ρc(T)=(a/T)exp(Δ/T)+bT+c加以描述.电阻率各向异性ρc/ρab随掺杂浓度增大而增大.     

用雷诺应力模型计算旋风分离器中气-固两相流动

针对分离器内部的复杂的三维强旋转、气-固两相湍流运动,采用雷诺应力模型(SSG),利用贴体网格技术,模拟计算了分离器内部流动,并将计算结果与实验数据进行分析、比较。分离器内的固体颗粒运动采用涉及湍流扩散影响的随机轨道模型和确定轨道模型,在流场计算的基础上,模拟了不同直径的颗粒在分离器内的运动规律及颗粒分离效率,并同理论和实验得到的数据进行了比较。     

高斯过程上确界的大偏差概率及其在经验过程中的应用

设P为无原子的球对称d维分布(d≥1),为服从P的i.i.d.样本,p_n是由这个样本所确定的经验测度,记S_(d-1)={∈R~d,=1}, 这里记号‖·‖表示欧氏模,对每一个∈S_(d-1),t∈R~1,记H=为R~d中的开空半间,I_(H(,t))关于H(,t)的示性函数,为方便起见,以下总记Pf∫fdP.又记