利用动态反射法对手性液晶Bragg反射的分析

利用动态反射法对手性液晶材料的选择性反射特性进行了分析。根据理论分析结果，利用MATLAB程序计算了手性液晶膜层的反射光谱，得到了反射光谱随手性液晶的螺距和折射率变化的关系；利用动态反射法可以较为方便、快速地对手性液晶膜的Bragg反射特性进行数值求解分析，分析和计算结果可以为反射式液晶显示的设计和计算提供理论参考。由于在数值求解中引入了简化条件，因此该计算方法只能应用于△n值较小的情况，当Δn值较大时，应该用其他求解方法来完成计算分析工作。     

No negative semantic priming from unconscious flanker words in sight.

In replicating 1 of the within-language conditions of E. Fox's (1996) Experiment 1, the authors confirmed that unattended words presented 2.4° above and below fixation are mostly unavailable to awareness. However, no negative semantic priming was observed in a lexical decision on a probe letter string appearing about 1 s later, which does not replicate Fox's finding. These results are compatible with the hypothesis underlying the present study, according to which positive semantic priming, if any, rather than negative semantic priming is expected in Fox's situation. The reason is that unavailability to awareness of the parafoveal words is not achieved by means of an act of selective inhibition combined with attentional diversion through masking but is achieved simply by means of perceptual degradation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Total internal reflection microscopy for live imaging of cellular uptake of sub-micron non-fluorescent particles

This paper presents a simple, high-resolution, non-fluorescent imaging technique called total internal reflection microscopy (TIRM) and demonstrates its potential application to real-time imaging of live cellular events. In addition, a novel instrument is introduced that combines the simplicity of TIRM with the specificity afforded by dual-colour total internal reflection fluorescence (TIRF) microscopy and allows sequential imaging with the two modalities. The key design considerations necessary to apply these imaging modes in a single instrument are discussed. The application of TIRM alone yielded high-resolution live images of cell adherence to a poly- l -lysine modified substrate, whereby fine cellular structures are imaged. Non-fluorescent imaging of the uptake of sub-micron–sized polymeric particles by live cells is also demonstrated. Finally, images of fluorescently labelled cells were obtained in TIRF mode, sequentially to images obtained of the same cell in TIRM mode. Visual information gained using TIRF is compared with TIRM to demonstrate that the level of cell structure information obtainable with our total internal reflection microscope is comparable with the TIRF technique.     

甲醇精馏系统常压塔负压问题的研究

介绍了400 kt/a煤制甲醇装置甲醇精馏系统的工艺流程,分析了常压塔出现负压问题的危害。从工艺和设备上分析了常压塔出现负压的原因,并提出合理有效的解决方案,保证了甲醇装置的安全稳定运行。     

一种能抑制HBT Kink效应的新型复合管

介绍了GaAs异质结双极型晶体管(HBT)的Kink效应及其对宽带匹配的影响,并根据负反馈原理,提出了一种新型的HBT复合管结构.通过对该结构进行小信号分析和计算机软件仿真,该复合晶体管在整个测试频段内输出阻抗接近于一个简单的RC串联电路,并且输出电阻在很宽的频率范围内保持稳定.采用2 μm InGaP/GaAs HBT半导体工艺技术流片测试,结果表明,在0.1～20 GHz(接近该HBT的截止频率)的频率范围内所提出的新型HBT复合管抑制了Kink效应并与理论分析结果及计算机仿真结果相吻合.采用该复合管作为宽带放大器的有源器件可以在很大程度上简化匹配电路的设计并且不会显著增加芯片面积和功耗.     

电流激励蔡氏电路混沌的解析预测

考虑到蔡氏电路受周围电路的影响,故将受周围影响的蔡氏电路做了等效处理,并将其等效为电流激励蔡氏电路。这里首次用解析的方法对三阶非线性微分方程能够产生混沌的参数范围进行预测,利用该方法得出电流激励蔡氏电路产生混沌的必要参数条件。通过数值仿真证明了该等效电路具有极其丰富的混沌动力学行为,仿真结果与解析预测结果有较好的吻合性。     

一种无运放电流模式带隙基准设计

为满足集成电路中低功耗／低温度系数的要求,基于负反馈钳位原理,采用分段线性补偿技术,通过在高低温度段分别插入非线性电流修正项对基准进行了曲率补偿,得到一种新型的无需运放的曲率补偿电流模式带隙电压基准源。仿真得到典型工艺下电路在室温27℃,工作电压4．5V下输出电压1．25062V,工作电流小于38pA,功耗小于170μW。在-40～＋150℃。宽温度范围内,基准电压在1．25018～1．25086V之间变化,温度系数约为2．86ppm／℃。     

1.9GHz0.18μm CMOS低噪声放大器的设计

针对1.9GHzPHS和DECT无线接入系统的应用,提出了一种可工作于1.2V电压的基于源级电感负反馈共源共栅结构而改进的CMOS低噪声放大器,并对其电路结构、噪声及线性特性等主要性能进行分析。并与传统的低噪声放大器进行对比,该电路采用两级放大结构,通过加入电容和电感负反馈可以分别实现低功耗约束下的噪声优化和高的线性度。采用TSMC0.18μm CMOS工艺模型设计与验证,实验结果表明：该低噪声放大器能很好满足要求,且具有1.4dB的噪声系数和好的线性度,输入1dB压缩点-7.8dBm,增益11dB,功耗11mW。     

FBG反射谱展宽效应在轨道传感器中的应用研究

实验验证了光纤Bragg光栅(FBG)在非均匀应力下的反射谱展宽效应,并将这种展宽效应应用于轨道列车轮重、位置和轴数的监测。将FBG传感器置于铁轨特定位置,当受非均匀应力时,列车轮重的增加会引起FBG反射谱展宽,反映为检测光强增大。利用模型验证了FBG反射谱分别在温度、均匀应力及非均匀应力下的变化,根据有限元分析模拟铁轨模型的应变分布,进而通过模型实验和实际测试验证了这种方案的可行性。     

红外光谱鉴定混合树脂的结构

红外光谱是高分子聚合物鉴定最常用的方法之一。通过单点衰减全反射及透射方法对比分析,鉴定了3种混合树脂的结构。