微波水解衍生高效液相色谱法测定饲料中的氨基酸

建立了一种微波水解衍生高效液相色谱同时测定饲料中17种氨基酸含量的方法。采用2,4-二硝基氯苯作为柱前衍生试剂,利用C_(18)色谱柱分离。二极管阵列检测器进行检测,检测波长为360 nm,并对微波水解时间及温度进行优化。17种氨基酸在2.5~50 mg/L范围内呈良好线性关系,相关系数为0.990 7~0.999 9;相对标准偏差为0.88%~4.2%;加标回收率为90.6%~107.2%;检出限为0.15~2.37 mg/L。研究结果表明,150℃下微波水解16 min的结果与传统加热水解(110℃,24 h)的效果基本相同。该方法分析时间较短,灵敏度较高,可用于饲料中氨基酸含量的检测。     

单模光纤激光极限功率的数值研究

对光纤激光极限功率的探索和其受限因素的分析, 有利于为大功率光纤激光器的发展提供理论依据和实验指导. 本文考虑热效应、光效应、非线性效应和抽运亮度等因素对光纤激光极限功率的影响, 分析了掺镱和掺铥光纤的极限功率和受限因素. 在此基础上, 结合激光在光纤中单模传输的条件, 计算了单模掺镱和掺铥光纤激光的极限功率. 计算结果表明, 在现有技术条件下, 使用常规的976 nm和793 nm激光二极管抽运, 单模掺镱和掺铥光纤激光的极限功率分别为4.2 kW和7.8 kW, 其中单模掺铥光纤激光的功率水平还远低于它的极限功率的原因是受抽运亮度的限制. 最后分析指出减小纤芯的数值孔径和改进少模光束的光束质量是提升单模光纤激光极限功率的重要途径.     

光纤放大器受激布里渊散射效应抑制

提出了一种多波长窄线宽光纤放大器,其种子光由多个单频激光耦合而成,所有单频激光波长几乎相等（波长间隔小于1 nm）,频率间隔大于两倍布里渊频移。建立了此类多波长窄线宽光纤放大器的完整理论模型,分析了放大器中受激布里渊散射（SBS）与种子数目的关系。搭建了双波长和三波长窄线宽光纤放大器,进行SBS阈值输出功率测定实验。实验结果与理论模拟结果基本一致,验证了理论模型的合理性;双波长和三波长放大可以有效抑制SBS效应,大幅提高放大器输出功率。     

钆对Mg-2Al-1Zn合金高温力学性能的影响

研究了Gd的添加对AZ21基体合金高温（200℃）力学性能和抗蠕变性能的影响。结果表明：AZ21-xGd合金由-αMg和Al2Gd两相组成,中间相Al2Gd使合金高温拉伸性能和抗蠕变性能得到显著提高,但降低了合金的延伸率。在Gd添加量为2%（质量分数）时,200℃下合金的抗拉强度和屈服强度分别达到148和90 MPa,但随着Gd含量的增加,高温拉伸强度有所下降;当Gd添加量为3.5%时,在200℃/50MPa蠕变条件下,合金70 h的蠕变量为1.2%,第二阶段蠕变率比AZ21基体合金下降了1个数量级。晶界上的Al2Gd中间相数量逐渐增多是提高合金的抗蠕变性能的主要原因,但在晶界上过多的Al2Gd中间相不利于提高合金的高温强度。     

Effects of Inertia on Evolutionary Prisoner's Dilemma Game

Considering the inertia of individuals in real life,we propose a modified Fermi updating rule,where the inertia of players is introduced into evolutionary prisoner's dilemma game(PDG) on square lattices.We mainly focus on how the inertia affects the cooperative behavior of the system.Interestingly,we find that the cooperation level has a nonmonotonic dependence on the inertia:with small inertia,cooperators will soon be invaded by defectors;with large inertia,players are unwilling to change their strategies and the cooperation level remains the same as the initial state;while a moderate inertia can induce the highest cooperation level.Moreover,effects of environmental noise and individual inertia are studied.Our work may be helpful in understanding the emergence and persistence of cooperation in nature and society.     

主振荡功率放大结构窄线宽全光纤激光器334 W高功率输出

 搭建了一台全光纤结构的窄线宽高功率掺镱光纤激光器。种子激光的输出功率大于40 mW,线宽窄于100 MHz。采用主振荡功率放大结构三级放大,主放泵浦功率为405 W时得到了334 W的窄线宽高功率激光输出,光光转换效率为82.4%。目前,激光器输出功率仅受限于泵浦功率,增加有效泵浦功率即有望进一步提高输出功率。     

A 330-W single-frequency retrievable multi-tone monolithic fiber amplifier

A single-frequency retrievable phase modulated multi-tone fiber amplifier is presented in theory and demonstrated in experiment. A multi-tone seed laser generated by a sine wave phase modulated single-frequency laser is employed for stimulated Brillouin scattering suppression in an all-fiber amplifier. A demodulation signal which is π phase shifted with respect to the modulation signal is used to retrieve the single-frequency laser from the multi-tone laser. In experiment, we first optimize the all-fiber master-oscillator power-amplifier. With this amplifier, we demonstrate a single-frequency retrievable multi-tone laser with 330-W output when driven by the multi-tone seed, while the ultimate output power is only 130 W when driven by the single-frequency laser. Then, we carry out an experiment for retrieving the single-frequency laser from the amplified multi-tone laser. Results indicate that the single-frequency laser can be retrieved with a sideband suppression of more than 20 dB. Retrieving an even higher power single-frequency laser is possible if a high power demodulator is available.     

Analysis of the Chinese air route network as a complex network

The air route network, which supports all the flight activities of the civil aviation, is the most fundamental infrastructure of air traffic management system. In this paper, we study the Chinese air route network (CARN) within the framework of complex networks. We find that CARN is a geographical network possessing exponential degree distribution, low clustering coefficient, large shortest path length and exponential spatial distance distribution that is obviously different from that of the Chinese airport network (CAN). Besides, via investigating the flight data from 2002 to 2010, we demonstrate that the topology structure of CARN is homogeneous, howbeit the distribution of flight flow on CARN is rather heterogeneous. In addition, the traffic on CARN keeps growing in an exponential form and the increasing speed of west China is remarkably larger than that of east China. Our work will be helpful to better understand Chinese air traffic systems.     

基于广义协调技术的剪力墙超单元

基于广义协调概念构造了可开洞的子结构式剪力墙超单元.该单元通过广义协调条件来实现墙与墙之间的协调性,这就导致墙元网格剖分的局部化,从而可在分析中容易地兼顾协调性、良态的单元以及粗细适度的网格尺寸.另外特别讨论了墙梁交接问题,并给出了正确的处理方法.该单元在复杂空间结构分析软件PMSAP中实现并在大量实际工程计算中应用,显示了良好的精度和适应性.