强化吸收过程的吸收稳定节能流程关键参数辨识与分析

针对一种吸收塔带有侧线抽出的节能流程,通过比较各参数在一定范围内的变化对系统总费用的影响程度,辨识了影响吸收稳定系统效益的关键参数,还考察了烯烃以及能源市场价格变化对参数辨识的影响。结果表明,凝缩油罐温度和补充吸收剂流量是两个关键操作参数,解吸塔压力、吸收塔侧线抽出量和抽出位置、稳定塔进料温度对系统总费用有着较大的影响,稳定塔进料位置、解吸塔热进料比例则对系统总费用的影响较弱。     

位阻胺选择性配方溶剂尾气处理装置工业应用

为了解决常规甲基二乙醇胺(MDEA)脱硫溶剂在低压下脱硫效果不理想,导致排放尾气中SO_2浓度升高的问题,利用位阻胺与H_2S反应具有良好活性、同时能较好抑制位阻胺与CO_2反应的特点,研究开发出了位阻胺选择性脱硫配方溶剂,并在处理量为1×10~4m~3/d的装置上进行中间放大试验的基础上,在中国石油西南油气田公司川中油气矿龙岗天然气净化厂硫磺回收加氢尾气脱硫装置上进行了工业应用。在工业应用期间,考察了溶剂在不同吸收塔板数、不同贫液入塔温度、不同溶液循环量等条件下的吸收性能,还考察了脱硫溶液的再生性能,确定了较适宜的工艺操作参数。应用1年后的考核结果表明:(1)该位阻胺选择性脱硫配方溶剂在进尾气脱硫吸收塔气体中H_2S含量为0.77%～3.96%、CO_2含量为23.91%～32.79%的气质条件下,可使净化尾气中H_2S含量低于30 mg/m~3;(2)与装置原用的常规MDEA相比,净化尾气中H_2S含量降低58.45%;(3)该位阻胺选择性脱硫配方溶剂的再生性能良好,再生后贫液中H_2S和CO_2含量均小于0.12 g/L。     

Prediction of mechanical dough development,water absorption and baking performance from farinograph parameters

Two systems for measuring flour water absorption (WA), the farinograph (FAR) and the Wheat Research Institute, 125 g mechanical dough development (MDD) standard bake test system, were compared using a representative sample of 20 commercial flours. A highly significant correlation (r = 0.93) was found which yielded the predictive equation: WA_MDD = 0.66 × WA_FAR + 181 The 95% prediction limits for 125 g MDD water absorptions from this equation were ± 15 g kg^?1. This degree of accuracy was largely due to excellent farinograph reproducibility. Other farinograph parameters (development time, stability and breakdown) were highly correlated with the work input required for 125 g mechanical dough development, but only development time was significantly correlated with the volume of loaves baked on the 125 g standard bake system. This lack of prediction of baking quality for the farinograph could partly be because it simulates bulk fermentation mixing, rather than the more intensive mixing of the mechanical dough development process used for the loaves in this experiment. However, the loaf volume range was diminished since sample preparation involved bulking flours by water absorption.     

Content of various elements in different parts of the tea plant and in infusions of black tea from Southern India

Contents of various elements in dyferent parts of the tea plant (shoot, mature leaf, small stem, thick wood and root), black tea manufactured by the crush-tear-curl and orthodox processes, and tea brew after 1 and 5 min of infusion were determined by inductively coupled plasma atomic emission spectrometry. From these, the amount of each element assimilated in the production of 1000 kg of marketable tea, as well as the quantity of each element brought into infusion and thus possib f y taken up through drinking tea, were calculated and discussed. Among the various elements assimilated by the tea plant, the shoot jraction (economically important for manufacturing commercial tea) contained high concentrations of N, P, K and Mg while the mature leaf accumulated Al, Bu, Ca, Cd, Mn, Pb and Sr. Of the dgerent elements brought into infusion while brewing black tea, the amount of K was found to be the largest (> 10000 μg g⁻¹ tea) followed by P (700–1200 μg g⁻¹), Mg (300–700 μg g⁻¹), Ca and A1 (each 150–300 μg⁻¹), Mn (60–150 μg g⁻¹), Cu, Na, Si and Z n (each 6–50 μg g⁻¹), B, Ba, Cr, Fe, Ni and Pb (each Id μg g⁻¹), and Sr, Co and Gd (each <1μg g⁻¹). The proportion of the totalamount of an element brought into infusion showed that the elements Ba, Ca, Fe and Sr were less soluble (<10 % of total amount), Al, B, Cd, Co, Cr, Cu, Mg, Mn, P, Pb, Si and Zn were moderately soluble (10–50 %), and K, Nu and Ni were highly soluble (>50%). The overall mean of the extent of solubility of all elements in 1 and 5 min showed that, out of the amount soluble in 5 min, about 68% was dissolved within 1 min.     

现代大气光学及其应用

简要介绍了现代大气光学的概念和内容,从大气分子吸收、大气气溶胶粒子光散射、大气湍流光学特性等方面阐述了现代大气光学的研究和应用状况。     

M型四能级原子与三模场相互作用系统的动力学特性

采用全量子理论,研究了M型四能级原子与三模场相互作用系统的动力学特性,通过数值计算,分析了光场失谐量、初始光子数和原子初始状态对原子布居概率和光子统计演化规律的影响.     

低截止频率多倍频程高增益对跖Vivaldi天线北大核心CSCD

针对传统对跖Vivaldi天线的最低截止工作频率较高、增益较低和方向性较差的问题,文中设计了一种新型超宽带对跖Vivaldi天线。融合运用辐射极板开矩形斜槽、加载吸收电阻和寄生矩形贴片等一系列电磁调控措施,扩展了天线的低频工作带宽;采取在天线极板间加载椭圆寄生贴片的技术方式大幅提高了天线的方向性和辐射增益。最后给出了天线的设计流程,从电场分布和表面电流分布的角度揭示了天线的微观工作机制。仿真和实测结果表明:天线的工作频带为0.85~16 GHz(近20倍频程),相对带宽达180%,在3 GHz以上频段增益均超过10 dBi,并且具有较好的端射方向性,在超宽带无线通信、雷达探测、电子对抗和遥感遥测等领域具有广泛的应用前景。     

脉冲激光沉积技术沉积温度对PZT/LSAT薄膜生长取向的影响

采用固相法分别制备了标准摩尔配比和铅过垦10%的两种靶材.并利用脉冲激光沉积技术(PLD)在镧锶铝钽(LaSrAlTaO3,LSAT)单晶衬底上成功制备了锆钛酸铅(Pb(Zr0.3Ti0.7)O3,PZT)铁电薄膜,在550～750℃沉积温度范围内研究了PZT薄膜的生长取向和铅含最对薄膜生长取向的影响.利用X射线衍射(XRD)仪和原子力显微镜(AFM)表征了薄膜生长取向和表面形貌.XRD测量表明在标准摩尔配比情况下薄膜牛长从550 C近似c轴取向逐渐过渡到750℃近似a轴取向,而在铅过量情况下薄膜生长取向无明显过渡性变化;AFM测量表明PZT薄膜在近似C轴和a轴生长情况下,表面均方根(RMS)粗糙度分别为16.9 nm和13.7 nm,而在混合生长无择优取向的情况下,薄膜表面均方根粗糙度达到68 nm,这可能是两种取向竞争生长的结果.     

795nm单模垂直腔面发射激光器

针对铷原予能级跃迁对光谱的特殊需求,设计并制备了795 nm单模垂直腔面发射激光器(VCSEL).根据对VCSEL的光场和模式的分析和计算结果,设计了单模VCSEL芯片结构.采用MOCVD技术生长了外延结构,制备了不同有源区直径的氧化限制型VCSEL芯片并进行了测试.当有源区直径从6 μm减小到3μm时,VCSEL芯片的边模抑制比(SMSR)由8.76 dB增加到34.05 dB,阈值电流由0.77 mA减小到0.35 mA.有源区直径为6,5,4和3μm的VCSEL芯片的输出功率分别为0.37,0.46,0.58和0.44 mW,有源区直径为4μm的VCSEL芯片的远场为圆形光束,发散角为15°.85℃时3.5 μm有源区直径的VCSEL芯片输出功率为0.125 mW,激射波长为795.3 nm.室温3 dB带宽大于8 GHz,满足了铷原子传感器对VCSEL单模光谱、输出功率及调制速率的要求.     

基于时域频域分析结合的调谐激光吸收光谱检测参数优化

随着调谐激光吸收光谱(tunable laser absorption spectroscopy, TLAS)技术在气体检测中的应用越来越广泛,二次谐波信号的质量与检测参数紧密相关,因而分析检测参数的优化方法很有意义。本文根据谱线预处理中的滤波参数、系统采样时间、锁相放大器的时间常数对信号的影响以及参数间的联系,总结检测参数的选取规律。根据滤波原理和不同浓度下信号的均方根误差(root mean squared error,RMSE)值选择合适的滤波阶数和窗宽。选择信噪比(signal-to-noise ratio,SNR)、RMSE、信号与噪声频域幅度之比(ratio of amplitude in frequency domain of signal to noise,f_SNR)3种评价指标的曲线变化趋势进行时频分析,得到最佳采样周期数为30,结合实验系统具体参数可计算最佳采样时间。通过信号主频带与截止频率的关系和滤波效果选择合适的时间常数。综合分析3个检测参数并总结选取方法,可提高二次谐波信号的质量。本文提出的参数选取方法对提高二次谐波在实际应用中的准确度有...