Time-resolved chirp evaluations of Gbit/s NRZ and gain-switched DFB laser pulses using narrowband Fabry-Perot spectrometer

A compact, easy-to-use, low-cost spectrometer for solving the chirped spectrum of DFB lasers is demonstrated using narrowband Fabry-Perot etalons with resolutions comparable to grating spectrometers. Time-resolved chirp measurements of Gbit/s NRZ and gain-switched DFB laser pulses are presented.<>     

粗苯放散气体回收系统的开工调试经验

介绍了焦化厂粗苯放散气体回收系统开工调试的经验。     

碱聚二元体系黏度稳定性研究

活性碱NPS2是白色或无色粒状商品,1%溶液pH值为10.考察了由NpS-2和HPAM HTP(分子量2.85×107,水解度22.0%)组成的碱聚二元体系63℃、7.34 s-1下的黏度性能.8.0 g/L NPS-2 1.5 g/L HTP蒸馏水溶液,在63℃、曝气或无氧条件下老化印天,黏度损失分别为91%和25%.在很宽的加量范围考察外加各种阳离子对该二元溶液曝气3小时的黏度的影响,50 mg/L的Ca22 、Mg2 、Ca2 Mg2 (11)和10 mg/L的Fe2 使黏度分别下降66.9%、73.4%、76.3%和87.4%;Ca2 、Mg2 可与NPS-2反应生成沉淀;Fe2 在较低浓度时使黏度升高,较高浓度时使黏度下降.该二元溶液剪切后的黏度,随3000 1/S剪切时间延长(0.5～9.0 min)而下降,静置(4 h)后黏度恢复幅度则大体相同,剪切5 min后黏度随剪切速率增加(1000～5000 1/s)而下降,≥4000 1/s时黏度不再能恢复.含1.5g/L HTP)的二元溶液的黏度随NPS-2浓度的增加(0～15 g/L)而持续下降,不同NPS-2浓度(6.0～12.5 g/L)的二元溶液的黏度随温度升高(30～80℃)大体上呈直线下降.图8参5.     

Air-Oxidation Behavior of a Cu60Hf25Ti15 Bulk Metallic Glass at 375–520 °C

The oxidation behavior of a Cu₆₀Hf₂₅Ti₁₅ bulk metallic glass was studied over the temperature range of 375–520 °C in dry air. The oxidation kinetics of the amorphous alloy generally followed the parabolic law at all temperatures, with an oxidation rate increasing with temperature. The oxidation rates of the amorphous alloy were much higher than those of polycrystalline pure-Cu, implying that the additions of Hf and Ti accelerated the oxidation reaction. The composition of the scales formed on the amorphous alloy was strongly temperature-dependent, since they consisted mostly of Cu₄O₃ and CuO with minor amounts of HfO₂ at T ≤ 450 °C, while mostly CuO with minor amounts of HfO₂ and Cu₂TiO₃ were detected at higher temperatures. In addition, nanocrystalline Cu₅₁Hf₁₄ and Cu₃Ti₂ phases were detected on the substrate after oxidation at T ≥ 450 °C, indicating the occurrence of phase transformation.     

河北涞水、易县、涞源、涉县等地历史建筑遗存考察纪略:刘敦桢、莫宗江、陈明达等前辈留下的启示和思考

自1934年秋开始．中国营造学社刘敦桢先生偕研究生莫宗江、陈明达、赵正之等先生．曾以平汉铁路为中心，先后三次踏查河北省西部的古建筑。其中第一次踏查自1934年九月下旬出发．先至定兴县，调查城内元大德十年所建的慈云阁：次赴县西二十五里同里镇．测绘调查石柱村北齐标异乡义慈石柱；再由同里往易县．经过燕故都北部．于易县逗留近半月．先调查测绘城内开元寺．     

In situ preparation of N,N-dimethyl-n-butylamine for 2,6-dimethylphenol polymerization

2,6-Dimethylphenol (2,6-DMP) polymerization with a catalytic complex of Cu₂O/HBr/N,N'-di-tert-butylethylene diamine (DBEDA)/N,N-dimethyl-n-butylamine (DMBA)/dibutylamine (DBA) was studied, in which DMBA was prepared in situ from the methylation of n-butylamine over four different solid acid catalysts (two different γ-alumina, one silica-alumina, and one zeolite). The effectiveness of the unpurified methylation product solutions for promoting the 2,6-DMP polymerization was strongly dependent on the type of solid acid catalysts used. The performance of the best one (untreated product solution from the methylation reactor with Condea γ-alumina catalyst) was very similiar to that of the reagent grade DMBA. Infrared spectrum studies showed that DMBA acted as the external base for the 2,6-DMP polymerization catalyst system to neutralize the excess hydrobromic acid and to increase the polymerization rate. © 1995 John Wiley & Sons, Inc.     

Thermal conductivities of powder-filled epoxy resins

Effective thermal conductivities of powder-filled epoxy composites were experimentally obtained using a transient method. Fillers used were aluminum and cupric oxide. Comparisons of these data with published correlations indicate that Agari's model can give better fits. Nielsen's model may also give a good prediction of the shape of particles can be determined and values of parameters A and ?m are available. An alternative method of dealing with parameter C₂ in Agari's model is suggested. © 1993 John Wiley & Sons, Inc.     

激光引信及其在海防导弹上的应用前景

简述了 GaAs 激光器、光电探测器及激光引信的基本特点。说明了激光引信在海防导弹上应用的可行性。提出了为满足掠海导弹的需求所必须解决的关键技术和实施途径。展望了激光引信在导弹控制和导引等方面的应用前景。     

Biological Effects of Flammulina Velutipes Richin RE on Chinese Kunming Mice

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