光突发交换网中一种新的有优先权的冲突解决方案

提出了一种解决不同优先级突发包之间资源竞争的方案,分析了该方案下不同优先级的性能(时延和丢包率) .研究结果表明：高优先级突发包的平均时延和丢包率都远小于低优先级突发包,因此该方案能为高优先级突发包提供很好的QoS保障.     

All-optical format conversion of NRZ-OOK to QPSK and 16QAM signals via XPM in a SOA-MZI

This letter proposes a scheme for the format conversion of on-off keying (OOK) signal to quadrature phase-shift keying (QPSK) and 16-ary quadrature amplitude modulation (16QAM) signals via cross-phase modulation (XPM) in a semiconductor optical amplifier (SOA). Theoretical and experimental analyses of the format conversion scheme are conducted to validate its feasibility. The phase changing is obtained because of the XPM in the SOA. The QPSK and 16QAM signals are converted from the OOK signal. The performance of the 10 Gb/s format conversion system is evaluated and discussed. The receiver sensitivities of the converted QPSK and 16QAM signals after detection are -27.25 and -23.5 dBm, respectively, at a bit error rate (BER) of 109 .     

Remotely pumped EDFA-based 40-Gb/s downstream and 10-Gb/s upstream long-reach WDM PON employing RSOA and FBG equalizer

We propose a remotely pumped Er-doped fiber amplifier （EDFA）-based 40-Gb/s downstream and 10- Gb/s upstream transmission long-reach wavelength division multiplexing passive optical network （WDM- PON） scheme with downstream and upstream transmission implemented by quadrature phase-shift keying （QPSK） transceiver and reflective semiconductor optical amplifier （RSOA）-based intensity modulation direct detection （IM-DD）. Transmissions of the 40-Gb/s QPSK downstream, using a Mach-Zehnder mod- ulator, and the 10-Gb/s non-return-to-zero on-off keying （NRZ-OOK） upstream, using a 1.2-GHz RSOA equalized by fiber Bragg grating （FBG）, are demonstrated with 40-km fiber transmission.     

Experimental and theoretical analyses of RSOA-based colorless-ONUs with 4PAM signal in the up-link

A scheme that utilizes the 4-level pulse-amplitude-modulated (4PAM) signal as the re-modulated signal of colorless optical network units (ONUs) based on reflection semiconductor optical amplifiers (RSOAs) is proposed. The system with 10-Gb/s non-return-to-zero (NRZ) downstream and 5-Gb/s 4PAM upstream signals is theoretically analyzed and experimentally verified. Simulation and experimental results reveal that the 4PAM re-modulated signal yields better performance than the NRZ signal in the upstream. A receiver power penalty of 1.6 dB is also improved by the 4PAM signal at back-to-back (BtB) transmission, whereas another receiver power penalty of 1.5 dB improved after 30-km single mode fiber transmission, where 4PAM signals are used as upstream signal.     

气相色谱法在苯甲酸乙酯合成实验中的应用

苯甲酸乙酯合成实验是有机化学实验的重要内容,传统的判断反应终点的方法是依靠观察反应的水珠挂壁现象和反应时间来确定,只能定性判断,不能定量、准确地描述反应进行的程度。利用气相色谱仪分别采用内标法和外标法对反应进行监测,定量地判断终点,使学生借助现代的科学仪器加深对反应原理的理解。     

三维椭球隐身条件的严格推导及其隐身特性验证

基于坐标变换理论,提出并推导了任意轴比下三维椭球的隐身条件,得到了相应隐身罩材料本构参数张量的通解表达式.根据导出的本构参数张量,利用电磁仿真软件分别对不同轴比的三个典型算例进行仿真验证.仿真结果证实了所导出的本构参数张量的正确性.这些分析结果为隐身物理机理的进一步理解,以及三维隐身罩的设计奠定了更充分的理论基础.     

特高综合磁性能晶界扩散磁体的研究

采用Tb4O7,TbHx和Nd2O3+Tb4O7三种扩散源,通过晶界扩散技术制备出特高综合磁性能的钕铁硼磁体,对不同扩散源的扩散效果及扩散机制进行研究.采用TbHx进行晶界扩散,获得综合磁性能(BH)max+Hcj=84.26,矫顽力温度系数为-0.361％·℃-1的最佳钕铁硼磁体,SEM微观结构分析表明TbHx扩散源...     

直线的包络在几何光学中的一个应用

直线的包络在几何光学中的一个应用张民（内蒙古电力学校呼和浩特０１００１０）１问题的提出几何光学中，对平行于主光轴的光束照射在球面反光镜上，其反射光线会聚于一点的前题条件是平行光束必须具有“近轴性”，否则，不能会聚在球面反光镜半径的一半处．在几何光学中...     

三组分相图测绘中多个绿色化实验体系的确立

针对大学化学三组分体系液-液平衡相图测绘实验中乙酸正丁酯腐蚀滴定管聚四氟乙烯旋塞问题进行了实验方法改进，将原来的体积量取法更改为体积量取与质量量取相配合的实验操作方法。并在此基础上，考察了几种新的绿色化实验体系——醋酸丙酯/正己醇/醋酸异丙酯-乙醇-水体系在该实验中的操作可行性，最后对它们的实验效果进行了比较。     

Electromagnetic scattering of the carbon nanotubes excited by an electric line source

An analytical solution is presented for the electromagnetic scattering from an infinite-length metallic carbon nanotube and a carbon nanotube bundle.The scattering field and scattering cross section are predicted using a modal technique based on a Bessel and Hankel function for the electric line source and a quantum conductance function for the carbon nanotube.For the particular case of an isolated armchair (10,10) carbon nanotube,the scattered field predicted from this technique is in excellent agreement with the measured result.Furthermore,the analysis indicates that the scattering pattern of an isolated carbon nanotube differs from that of the carbon nanotube bundle of identical index (m,n) metallic carbon nanotubes.