氧化铁对石灰中温烟气脱硫活化机理的流化床实验分析

运用小型热态流化床对石灰与氧化铁混合物的中温烟气脱硫反应特性再次进行了分析。研究表明:在石灰中掺入一定比例的氧化铁可以显著提高钙利用率,氧化钙晶粒以氧化铁颗粒为核心进行固硫反应,破坏了形成表层致密产物层的条件,改变了石灰表层孔隙结构,使更多的内部孔隙暴露,为同硫反应向纵深发展创造了条件。     

氧化铁浆液脱硫的实验研究与理论分析

本文实验研究了氧化铁浆液在酸性环境下脱除烟气中的二氧化硫气体。实验在一自制的脱硫塔中进行。通过燃烧液化石油气来产生烟气,将氧化铁的超细粉加入水中作为脱硫介质。实验中研究了二氧化硫初始浓度、水气比对脱硫效率的影响。从实验结果可以看出,脱硫率随着水气比的增加而增大;随二氧化硫的初始浓度的增加,其脱硫率呈降低趋势。在文中同时分析了氧化铁浆液的脱硫机理和此方法脱硫的优点以及目前存在的问题。     

高温燃气脱硫的Mossbauer谱研究：氧化铁脱硫,失活与再生机理探讨

本文采用＾５＾７ＦｅＭｏｓｓｂａｕｅｒ谱学方法，跟踪考察氧化铁在高温（９７３Ｋ）燃气脱硫过程中的转化演变，取得有关其脱硫，失活与再生机理的明确信息。     

湿法液柱喷射烟气脱硫反应的实验研究

湿法液柱烟气脱硫技术是基于简易湿法石灰-石膏烟气法开发的新型湿法脱硫技术,本套设备在2000-2001年问进行了工业级示范实验运行,得到了湿法液柱脱硫反应的一些基本数据与规律。本文主要探讨了湿法液柱脱硫系统中液气比、吸收塔浆液pH值、烟气温度和烟气中SO2含量等工艺参数对系统脱硫效率的影响规律,并进行了初步的机理分析,为进一步的改进湿法液柱烟气脱硫系统的工艺奠定了基础。     

氧化铁薄膜制备方法的改进

氧化铁薄膜具有很高的极限磁记录密度．然而，单相四氧化三铁薄膜的制备却对工艺条件十分敏感，并且成膜的饱和磁化强度也远低于块状样品．在溅射过程中引入水蒸气、氧气和氩气的混合气体，一方面可以大大拓宽单相四氧化三铁薄膜的制备条件，另一方面也使得饱和磁化强度增加到４５０ ｅｍｕ／ｃｍ~３以上．本文对不同的氧化铁薄膜制备方法及磁性等进行了比较．     

中温烟气脱硫过程中CO2对脱硫剂钙利用率的影响

本文在300～600℃的中温区段,实验研究了CO2在烟气脱硫过程中与钙基脱硫剂发生碳酸盐还原反应,削弱脱硫效果的规律,发现石灰钙利用率随温度升高呈跳跃式变化,并因碳酸盐反应程度的迅速增加而在500℃附近出现低谷.由此明确了减小碳酸盐反应效应,提高脱硫剂钙利用率的途径,为进一步发展中温烟气脱硫工艺提供了重要依据.     

NO2对中温干法脱硫反应影响的实验研究

利用鼓泡床反应器对NO2对中温干法脱硫反应的影响开展了实验研究.分别采用分析纯CaO和工业级石灰两种物质作为吸收剂,在250℃和350℃两个反应温度下研究NO2对吸收剂转化率的影响.结果表明,NO2的存在可以提高吸收剂转化率;250℃下NO2的作用显著高于350℃;250℃下NO2浓度的增加对吸收剂转化率基本没有影响;在350℃时,对于分析纯CaO,NO2浓度的增加降低了吸收剂转化率,这主要是由于SO2与NO2的竞争反应引起的;工业级石灰内含杂质较多,对一些反应有催化作用,因而其反应现象与分析纯CaO略有不同.     

纳米氧化铁吸附脱除单质汞的实验研究

在固定床反应器上研究了N_2气氛下纳米氧化铁对单质汞的吸附脱除特性,探讨了吸附剂颗粒尺寸,反应床温度,停留时间及表面羟基基团对纳米氧化铁除汞性能的影响。研究表明,与普通氧化铁颗粒瞬间到达穿透相比,纳米氧化铁具有更强的汞吸附能力,相同条件下其80%穿透时间达到45 min,XPS分析表明,纳米氧化铁表面85%以上均为氧化态的汞。汞在纳米氧化铁上的吸附过程中化学反应起重要作用。在试验温度范围内,随着反应床温度增加,纳米氧化铁对汞的吸附性能提高幅度显著。反应前后样品的红外光谱分析结果表明,纳米氧化铁表面主要是游离态的羟基参与了汞吸附反应。     

水溶液中Ca(OH)2粒径分布研究

本文利用激光粒度分析仪研究了石灰产地、石灰尺寸和液固质量百分比对石灰水合所得浆液中Ca(OH)2粒径的影响.结果显示,石灰尺寸和液固质量百分比对浆液中Ca(OH)2粒径分布影响较小,而产地对粒径有一定影响.将平均粒径为5μm的分析纯Ca(OH)2粉末制备成浆液,其粒径增大到13μm,表明Ca(OH)2在水中发生团聚.因此,单纯依靠改变制备条件或石灰来源,对于减小Ca(OH)2的粒径作用不大,必须采用其它措施如添加分散剂来减轻团聚并减小粒径.     

蒸汽活化对钙基脱硫剂孔结构及固硫能力影响的实验研究

本文用实验方法研究了在电站锅炉排烟温度条件下，水蒸汽对钙基脱硫剂的活化作用．实验结果表明，蒸汽活化使得脱硫剂孔结构发生了显著变化并明显改善了脱硫剂的固硫能力．这为进一步了解活化机理及开发省水，经济的排烟脱硫技术提供了依据．     

Theoretical analysis and simulation of conjugate heights for dual-conjugate AO system in lidar

A multi-conjugate adaptive optics （MCAO） can offer a possibility of widening field of view （FOV） characterized by the isoplanatic angle, and the choose of conjugate height becomes a basic problem for MCAO, which influences the size of iosplanatic angle. Considering the application of lidar, the isoplanatic angle＇s expressions of two deformable mirrors （DMs） MCAO for uplink and downlink are deduced. The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed, and the isoplanatic angles are further analyzed. The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude. Moreover, the optimal conjugate height changes with the propagation distance.     

Quick single-photon detector with many avalanche photo diodes working on the time division

Due to the limit of response speed of the present single-photon detector, the code rate is still too low to come into practical use for the present quantum key distribution (QKD) system.A new idea is put up to design a quick single-photon detector.This quick single-photon detector is composed of a multi-port optic-fiber splitter and many avalanche photo diodes (APDs).Au of the ports with APDs work on the time division and cooperate with a logic discriminating and deciding unit driven by the clock signal.The operation frequency lies on the number N of ports, and can reach N times of the conventional single-photon detector.The single-photon prompt detection can come true for high repetition-rate pulses.The applying of this detector will largely raise the code rate of the QKD, and boost the commercial use.     

Characterization of PolyA and PolyC mismatches by Raman spectroscopy

A.C mismatches are studied by Raman spectral characterization of PolyA, PolyC, and their equimolar complex in solution of 0.14 mol/L Na ,pH7.0.Experimental results show that A·C mismatches occur to be A/B (mainly A) conformers, and unlike Watson-Crick base pairing, this kind of mismatches is stabilized by only one hydrogen bond involving cytosine N4H2 and adenine N7.The formation of A·C complex makes the base stacking interactions much stronger, and conformation of the backbone more ordered, which leads to obvious Raman hypochromic effect with some shifts in corresponding bands.     

Improvement of four-wave mixing-based wavelength conversion efficiency in dispersion shifted fiber by 40-GHz clock pumping

40-GHz clock modulated signal as a pump to improve the efficiency of four-wave mixing (FWM)-based wavelength conversion in a 26.5-km dispersion shifted fiber (DSF) is investigated. The experimental results demonstrate that the conjugated FWM component has higher intensity with the clock pumping than that with the continuous-wave (CW) light pumping. The improvement of FWM-based wavelength conversion efficiency is negligible when the pump power is less than Brillouin threshold. But when the pump power is greater than Brillouin threshold, the improvement becomes significant and increases with the increment of pump power. The improvement can increase up to 9 dB if pump power reaches 17 dBm.     

Speech enhancement by array crosstalk resistant ANC and spectrum subtraction

Microphone array-based speech enhancement has great importance for speech communications and speech recognition. To reduce the aperture of the microphone array and to increase the effect of the speech enhancement will greatly broaden the application areas of the microphone array. An array crosstalk resistant adaptive noise cancellation method is therefore presented. And then an improved spectral subtraction algorithm is further cascaded to obtain better enhancement results. Theoretic analysis and experiments indicate that the proposed scheme needs only a very small microphone array while it simultaneously achieves a higher SNR improvement. Besides, the proposed scheme can be used in many noisy environments and is easy for real-time implementation.     

Multi-pulse operation of a Kerr-lens mode-locked femtosecond laser

Our experimental results show that the presence of a proper amount of negative group velocity dispersion is essential to multi-pulse operation of a Kerr-lens mode-locked femtosecond laser. We demonstrate that the pulse separations and the number of pulses contained within a cavity round trip are strongly dependent on the initial perturbations. The results allow us to get a better understanding on the influences of the convoluted self-phase modulation and intra-cavity dispersions on the stable multi-pulse oscillation in a Kerr-lens mode-locked femtosecond laser.     

Propagation of Helmholtz-Gauss beams in weak turbulent atmosphere

Based on the Rytov approximation of light propagation in weak turbulent atmosphere,the closed-form expressions of field and average irradiance of each one of the four fundamental families of Helmholtz-Gauss (HzG)beams:cosine-Gauss beams,stationary Mathieu-Gauss beams,stationary parabolic-Gauss beams,and Bessel-Gauss beams,which are propagating in weak turbulent atmosphere,are obtained.The results show that the field and average irradiance can be written as the product of four factors:complex amplitude depending on the z-coordinate only,a Ganssian beam.a factor of complex phase perturbation induced by atmospheric turbulence,and a complex scaled version of the transverse shape of the non-diffracting beam.The effect of weak atmospheric turbulence on irradiance distribution of the HzG beam can be ignored.     

An effective method for reducing speckle noise in digital holography

An effective method for reducing the speckle noise in digital holography is proposed in this paper.Different from the methods based on classical filtering technique,it utilizes the multiple holograms which are generated by rotating the illuminating light continuously.The intensity images reconstructed by a series of holograms generated by rotating the illuminating light possess different speckle patterns.Hence by properly averaging the reconstructed intensity fields,the speckle noises can be reduced greatly.Experimental results show that the proposed method is simple and effective to reduce speckle noise in digital holography.     

Influence of purity of HfO2 on reflectance of ultraviolet multilayer

The impurities in two kinds of HfO2 materials and in their corresponding single layer thin films were determined through glow discharge mass spectrum technology and secondary ion mass spectrometry(SIMS) equipment respectively.It was found that ZrO2 was the main impurity in the two kinds of HfO2 either in the original HfO2 materials or in the electron beam deposited films.In addition,the difference of Zr content in the two kinds of HfO2 single laver films was much laxger than that of the other impurities such as Ti and Fe.which showed that it was just ZrO2 that made the difference between the optical performance of the film products including the two kinds of HfO2.With these two kinds of HfO2 and the same kind of SiO2.we deposited HfO2/SiO2 multilayer reflective coatings at the wavelength of 266 nm.Experimental results showed that the reflectances of these two mirrors were about 99.85% and 99.15% respectively,which agreed well with the designed results what were based on the optical constants obtained from the corresponding single layer thin films.