Second-order temporal interference of two independent light beams at an asymmetrical beam splitter

The second-order temporal interference of classical and nonclassical light at an asymmetrical beam splitter is discussed based on two-photon interference in Feynman's path integral theory. The visibility of the second-order interference pattern is determined by the properties of the superposed light beams, the ratio between the intensities of these two light beams, and the reflectivity of the asymmetrical beam splitter. Some requirements about the asymmetrical beam splitter have to be satisfied in order to ensure that the visibility of the second-order interference pattern of nonclassical light beams exceeds the classical limit. The visibility of the second-order interference pattern of photons emitted by two independent single-photon sources is independent of the ratio between the intensities. These conclusions are important for the researches and applications in quantum optics and quantum information when an asymmetrical beam splitter is employed.     

产妇血及其新生儿脐带血中铁、锌、铜、硒含量的研究

选取包头市区正常产妇６８名及其所生新生儿作为研究对象。分娩后抽取产妇肘静脉血及新生儿脐动脉血，分析其血清中铁、锌、铜、硒的含量．研究结果揭示：新生儿脐带血清中铁、铜、硒的含量均高于产妇血清中的含量，铁与铜有显著性差异（Ｐ＜０．０５），硒的差异不显著（Ｐ＞０．０５）；而锌则相反，新生儿脐带血清中的含量低于产妇血清中的含量，二者有高度显著性差异（Ｐ＜０．０１）。产妇血清中Ｆｅ／Ｚｎ、Ｃｕ／Ｚｎ、Ｓｅ／Ｚｎ比值分别为３．８３、２．７８、０．０８；而新生儿脐带血清中Ｆｅ／Ｚｎ、Ｃｕ／Ｚｎ、Ｓｅ／Ｚｎ比值则各为９．５６、６．８０、０．１９，进一步说明新生儿脐带血清中的锌含量降低，其它元素含量增加。     

油漆工头发中铁、锌、铜水平的研究

对８２名苯作业工人和１００名对照组工人的发铁、发锌和发铜含量水平进行了研究。结果揭示，油漆作业工人发铁含量为１０．３×１０－６±２．３×１０－６，明显低于对照组（１４．４×１０－６±３．１×１０－６）．Ｐ＜０．０１，发铜含量为７．４×１０－６±１．２×１０－６，亦低于对照组（９．８×１０－６±１．３×１０－６）．Ｐ＜０．０５；发锌含量为１６９．２×１０－６±２６×１０－６，与对照组（１７２．５×１０－６±２８×１０－６）基本相同，Ｐ＞０．０５．     

Second-order interference of two independent and tunable single-mode continuous-wave lasers

The second-order temporal interference of two independent single-mode continuous-wave lasers is discussed by employing two-photon interference in Feynman's path integral theory. It is concluded that whether the second-order temporal interference pattern can or cannot be retrieved via two-photon coincidence counting rate is dependent on the resolution time of the detection system and the frequency difference between these two lasers. Two identical and tunable single-mode continuous-wave diode lasers are employed to verify the predictions. These studies are helpful to understand the physics of two-photon interference with photons of different spectra.     

急性心肌梗死患者血清中镉铅铍含量的研究

为急性心肌梗死患者的防治提供新的科学依据,对135例急性心肌梗死患者,取其肘静脉血清,用JY－70（Ⅱ）合并型等离子体发射光谱仪 测定微量元素含量,与对照组进行对比分析。结果显示,心肌梗死患者血清铍的含量高于对照组, 而血清镉和铅的含量低于对照组。