The effect of spherical aberration on temperature distribution inside glass by irradiation of a high repetition rate femtosecond pulse laser

In this paper, we study the effect of spherical aberrations on the light intensity and the temperature distribution in the focal region in a 250-kHz femtosecond laser irradiated Ag⁺-doped borosilicate glass. When a focused beam goes through an interface between air and glass, spherical aberration will result in the separation of the focal point and then cause a clear change of the light intensity distribution along the incident direction. That phenomenon will further influence the longitudinal cross-section temperature distribution in glass. Here we use Ag nanoparticle formation as a marker for establishing temperature distribution and we find that the formation of nanoparticle shows a strong dependence on the temperature field and the detailed precipitation process is also discussed.     

2,2,6,6-四甲基哌啶氮氧自由基与卤仿形成卤键或氢键的理论研究

利用理论计算化学研究了2,2,6,6-四甲基哌啶-N-氧自由基与卤仿形成卤键和氢键络合物的可能性. 从分子静电势、络合物分子的结构参数、络合物的作用能以及自然键轨道理论的角度着手研究. 结果表明,卤键与氢键络合物的键合能均遵循氯化物<溴化物<碘化物,氢键络合物作用强度大于相应的卤键络合物. 因此,卤仿与2,2,6,6-四甲基哌啶-N-氧自由基之间作用模式氢键为主. 需要注意的是,碘仿形成卤键的作用强度与氢键相当,因此在碘仿中,卤键与氢键两种模式应该竞争性的存在.     

火焰原子吸收光谱法测定不锈钢中高含量镍

镍的火焰原子吸收光谱法的测定已有报道,在测定中大多采用232.0 nm吸收线。光谱分析波长适合于微量镍的测定,但不适于不锈钢中高含量镍的测定。国家标标准GB/T 223.25—1994方法对不锈钢中镍的测量范围为0.030%～2.00%,不适合应用于样品中镍含量大于2%的样品的测定,应选用丁二酮肟重量法和EDTA滴定法测定镍量,操作繁琐,耗时长。针对此问题,本工作采用火焰原子吸收光谱法,采用镍341.5 nm次灵敏线测定不锈钢中高含量镍,样品经盐酸-硝酸-水(3+1+12)溶液溶解后定     

木龙河斜拉跨越结构的静态力学分析

利用有限元法对木龙河斜拉跨越结构进行了力学分析. 结果表明: 安装时索 具有一定的预应变可以提高结构的强度和刚度, 但预应变太大反而降低结构的刚度和强度, 预应变存在一个最优值, 且最优值与结构的形式和载荷有关; 在工作载荷或充水载荷作用下, 结构的强度刚刚满足要求; 在极限载荷作用下, 结构的强度不满足要求; 结构中最大应力出 现在左塔架顶端连接索处、右塔架顶端连接索处和管桥架中间上缘杆.     

Detecting the possibility of a type of photon number splitting attack in decoy-state quantum key distribution

The existing decoy-state quantum key distribution (QKD) beating photon-number-splitting (PNS) attack provides a more accurate method to estimate the secure key rate, while it still considers that only single-photon pulses can generate secure keys in any case. However, multiphoton pulses can also generate secure keys if we can detect the possibility of PNS attack in the channel. The ultimate goal of this line of research is to confirm the absence of all types of PNS attacks. In particular, the PNS attack mentioned and detected in this paper is only the weaker version of PNS attack which significantly changes the observed values of the legitimate users. In this paper, under the null hypothesis of no weaker version of PNS attack, we first determine whether there is an attack or not by retrieving the missing information of the existing decoy-state protocols, extract a Cauchy distribution statistic, and further provide a detection method and the type I error probability. If the result is judged to be an attack, we can use the existing decoy-state method and the GLLP formula to estimate the secure key rate. Otherwise, the pulses with the same basis received including both single-photon pulses and multiphoton pulses, can be used to generate the keys and we give the secure key rate in this case. Finally, the associated experiments we performed (i.e., the significance level is 5%) show the correctness of our method.     

Tl-2212本征约瑟夫森结型负阻器件及负阻放大器

我们利用Tl—2212超导薄膜制作出了的本征约瑟夫森结型负阻器件．对于4μm长3μm宽的微桥型负阻器件，峰值电压为0．09V，峰值电流为1．44mA．谷值电压为0．75V，谷值电流为1．05mA，线性区间内负阻阻值约为-1400Ω利用这种器件．制作了简单的负阻并联式电流放大器．实验证明它确实对信号具有电流放大作用，放大倍数可以通过改变负载电阻的大小来改变．     

激光二极管泵浦Nd∶LMA激光器的连续波输出研究

报道用一个３Ｗ激光二极管端面泵浦Ｎｄ∶ＬＭＡ激光器。实验采用三镜折迭像散补偿腔。在１０５４ｎｍ波长，激光器连续输出功率达６２０ｍＷ，斜率效率为５０％，光－光转换效率２０％。在１０８３ｎｍ波长处，激光器连续输出功率为６４ｍＷ，斜率效率为６％，光－光转换效率２．１％。     

聚丙烯酰胺在油砂上吸附量和吸附

聚丙烯酰胺在油砂上吸附量和吸附焓宋湘杨冠英柯杰韩布兴＊赵扬阎海科（中国科学院化学研究所北京１０００８０）聚合物在固－液界面上的吸附对石油开采和环境治理等方面都很重要。因此，前人在此方面已进行了不少研究［１－３］。然而，聚合物的吸附受温度、盐类、ｐＨ值...     

Surface Tamm states in one-dimensional photonic crystals containing anisotropic indefinite metamaterials

Silica-based Yb 3+-doped glass is prepared by non-chemical vapor deposition.The drawn photonic crystal fiber(PCF) has a strong absorption at 976 nm and emission wavelength of approximately 1 037 nm.The intensity and spectral lineshape of the near infrared(NIR) luminescence of the Yb3+-doped PCF are recorded and discussed in terms of excitation power,excitation wavelength,fiber length,and Yb3+ ion concentration.The emission intensifies as the excitation power and Yb3+ ion concentration increase.The intensity of the shorter wavelength side of the luminescence spectrum decreases as the length of the PCF increases.