用于10Gb／s传输系统的电吸收调制器与分布反馈激光器集成光源

采用超低压（22×10^2Pa）选择区域生长（selective area growth，SAG）金属有机化学气相沉积（metal-organic chemical vapor deposition。MOCVD）技术成功制备了应变型InGaAsP／InGaAsP电吸收调制器（electroabsorption modulator，EAM）与分布反馈激光器（distribute feedback laser，DFB）单片集成光源的新型光电器件．实验结果表明。采用该技术制备的集成器件表现出了良好的性能

~(29)S双质子的同时发射

<正>近年来,双质子发射的现象被广泛研究。~(29)S核最外层两个质子处于2s1/2轨道,可能存在这种奇特的行为。先前的实验表明,~(29)S+~(28)Si的总反应截面有着异常大的值。这意味着~(29)S中最后2

干旱下植物气孔运动的调控

概述了植物气孔对大气干旱和土壤干旱的反应 ,认为植物气孔对大气干旱的反应并不是一种反馈机制 ;并就干旱条件下植物气孔运动的水力学和化学信号调控机制进行了简要论述 ,认为虽然化学信号调控干旱下气孔运动更为广泛 ,但 ABA不是唯一的化学信号 ,水分关系影响了信号的产生、运转和气孔对信号的敏感性 ,干旱条件下水力学和化学信号共同调控着植物的气孔运动

不同生育期干旱对冬小麦产量及水分利用效率的影响

用盆栽对冬小麦不同生育阶段进行不同程度水分调亏试验结果表明 :拔节—孕穗期、抽穗—扬花期和灌浆—成熟 3个阶段内 RW上限为 4 0 %、5 0 %、60 %的水分亏缺均引起了产量的极显著下降 ,而且水分亏缺越严重 ,产量降低越大。在 3个生育阶段内进行 RW上限为 4 0 %的水分调亏减产幅度都很大 ,而且 3个生育阶段之间差异不明显 ;进行 5 0 %、60 %水分调亏 ,其减产程度则与生育期有关。灌浆—成熟期的减产程度大于前二个时期 ,这可能与前二个阶段复水后作物的补偿生长有关。不同生育期水分亏缺对冬小麦产量构成因素的影响也不同 ,拔节—扬花期水分亏缺主要减少了穗粒数 ,灌浆—成熟阶段的水分亏缺主要减少了千粒重

Determination of aliphatic amines from soil and wastewater of a paper mill by pre-column derivatization using HPLC and tandem mass spectrometry (HPLC-MS/MS)

A pre-column derivatization method for the sensitive determination of aliphatic amines using the labeling reagent 1,2-benzo-3,4-dihydrocarbazole-9-ethyl chloroformate (BCEOC) followed by HPLC with fluorescence detection and APCI/NIS identification in positive-ion mode has been developed. The chromophore of 2-(9-carbazole)-ethyl chloroformate (CEOC) reagent was replaced by the 1,2-benzo-3,4-dihydrocarbazole functional group, which resulted in a sensitive fluorescence derivatizing reagent, BCEOC, that could easily and quickly label amines. Derivatives were stable enough to be efficiently analyzed by HPLC and showed an intense protonated molecular ion corresponding m/z [M + H](+) with APCI/MS in positive-ion mode. The collision induced dissociation of the protonated molecular ion formed characteristic fragment ions at m/z 264.1, m/z 246.0 and m/z 218.1, corresponding to the cleavages of CH2CH2O-CO, CH2CH2-OCO, and N-CH2CH2O bonds. Studies on derivatization conditions demonstrated that excellent derivatization yields close to 100% were observed with a 3 to 4-fold molar reagent excess in acetonitrile solvent, in the presence of borate buffer (pH 9.0) at 40 degrees C for 10 min. In addition, the detection responses for BCEOC derivatives were compared with those obtained with CEOC and FMOC as labeling reagents. The ratios I-BCEOC/I-CEOC and I-BCEOC/I-FMOC were, respectively, 1.40-2.76 and 1.36-2.92 for fluorescence responses (here, I was the relative fluorescence intensity). Separation of the amine derivatives had been optimized on an Eclipse XDB-C-8 column. Detection limits calculated from an 0.10 pmol injection, at a signal-to-noise ratio of 3, were 18.65-38.82 fmol (injection volume 10 mu L for fluorescence detection. The relative standard deviations for intraday determination (n = 6) of standard amine derivatives (50 pmol) were 0.0063-0.037% for retention times and 3.36-6.93% for peak areas. The mean intra-and inter-assay precision for all amines were <5.4% and 5.8%, respectively. The recoveries of amines ranged from 96 to 113%. Excellent linear responses were observed with correlation coefficients of >0.9994. The established method provided a simple and highly sensitive technique for the quantitative analysis of trace amounts of aliphatic amines from biological and natural environmental samples.

基于自治及合作的整子制造系统

整子制造系统是智能制造计划中提出的一种未来的制造模式，本文对其概念、理论和研究状况进行了介绍和分析．整子是构造制造系统的一种模块，它具有自治性及合作性，而整子制造系统则追求快速适应环境变化的能力．整子制造系统采用了一种松弛的动态递阶控制结构．目前整子制造系统仍然处于对“下一代制造模式”的研究阶段，离实际应用还有一定的距离。