碳制氢过程的比较及直接制氢分析

本文对不同碳制氢过程进行了热力学分析,比较了相同进料条件下,采用不同过程进行碳制氢时,过程的冷煤气效率以及最终产物组成,并分析了“一步制氢”中温度、压力、不同进料比对最终产物组成的影响。结果表明,直接制氧适宜的气化温度为923-973 K;增加水蒸气分压力(气化压力随之增加),气体产物的量增加;吸收剂有一最佳的量。     

电解水制氢的实验研究

搭建了电解水制氢的实验装置,并利用该装置研究了氢气与氧气的产生率与电流及时间的关系,同时测定电解装置的能效因数.     

铜修饰铁矿石的化学链制氢特性实验研究

化学链制氢是一种耦合CO_2捕集的高效制氢技术,铁基载氧体常应用于化学链制氢技术。赤铁矿的反应活性低且易发生析碳导致氢气纯度低,本文通过浸渍法添加铜修饰铁矿石,提高反应活性和制氢纯度.实验在小型流化床上进行,考察了850℃下化学链制氢过程中铜修饰对载氧体的反应活性、制氢性能、循环反应性质和析碳现象的影响。结果表明,与铁矿石比较,添加铜修饰可以显著提高载氧体反应活性和氢气产量,并且铜的添加可以有效抑制析碳,获得高纯度的氢气。在循环过程中,铜修饰铁矿石展现出更好的循环稳定性。     

叠层扩散层对质子交换膜电解池性能影响的实验研究

质子交换膜电解水制氢技术的发展受到成本的约束。通过提高电流密度以提高单位质子交换膜电解池的氢产量可以降低单位应用成本，但高电流密度下电解池内部传质过电势的升高会导致制氢效率的下降。本文从降低质子交换膜电解池在高电流密度下的传质过电势入手，设计了有利于传质的“钛毡–钛网”式叠层扩散层结构，并进行对照实验分析了不同扩散层结构对电解池性能的影响规律。实验证明，钛毡叠加30目钛网的叠层扩散层结构可以使高电流密度(5 A/cm²)下的传质过电势降低至0.25 V(与钛毡或30目钛网作为扩散层相比，传质过电势分别降低了0.24 V与0.55 V)，本项工作也为后续扩散层结构的优化提供了思路。     

电站中液化天然气可用冷能的回收利用

液化天然气（ＬＮＧ）具有大量可用冷能。本文提出一种高效回收ＬＮＧ可用冷能的方法,即以蒸汽动力循环中气轮机排出的乏气为热源,结合天然气直接膨胀和二次冷媒动力循环。并对该循环进行了详细分析,对其参数进行了优化。利用这种方法,ＬＮＧ可用冷能的回收效率可达５５％左右。     

维持LNG冷能空分装置连续运行的方案研究

LNG(液化天然气)蕴含的冷能应用于空气分离,既节约了传统空分大量的压缩制冷功耗,同时也满足了日益增长的气体需求。由于接收站LNG的气化量在不同时段和不同季节因用户的用气波动而频繁变化,致使LNG冷能空分装置因冷量中断而被迫频繁停车,冷能空分项目的连续稳定运行受到了一定的制约。针对此问题,提出了利用液氮冷媒补冷,维持空分装置连续运行的方案,研究结果表明:LNG冷能供应中断时,通过利用液氮冷媒补冷可维持空分装置连续运行,相比较空分装置直接停车再冷开车,该方案经济上切实可行。     

基于临界区传热特性的LNG冷能与空分系统集成与优化

本文提出了一种利用LNG冷能的新型空分流程,利用LNG冷能冷却进入氮压机的下塔顶部氮气并使其节流液化,部分液体作为产品输出,部分液体流入过冷器后进入上塔顶部完成回流,节流产生的高压氮返回LNG冷能换热器补充冷能。本文采用MATLAB编程对该流程进行计算,并考虑冷热流体在临界区比定压热容随温度剧烈变化的特性,分析氮气压缩机入口温度与总压比对系统能耗、LNG冷能利用率的影响。计算结果表明:氮气压缩机入口温度的降低会同时降低氮压机耗功和LNG冷能利用率,系统等效能耗随其先降低后升高;氮气压缩机总压比的升高会增加氮压机耗功与LNG冷能利用率,但系统等效能耗随之降低;将氮气压缩机入口温度选定为准临界温度时冷能利用系统的等效能耗最低,LNG冷能的利用最高效,相较于已有文献研究结果,本研究所设计新流程的单位液体产品能耗与LNG冷能利用率等指标均有大幅度提高。     

LNG冷能利用的液体空分流程形式比较

通过对利用LNG将空气液化或氮气液化,两种不同的冷量传递方式的模拟计算,比较了利用LNG冷能的液体空分装置的两种流程组织形式的特点,并对装置的安全性进行分析。     

微生物电解池制氢研究进展（英文）

微生物电解池(MECs)是一种以微生物为电解制氢电池的阴极或阳极催化剂,将有机物间接转化为氢气的新型高效节能制氢技术.此类可再生制氢技术的开发,仍面临如何提高制氢速率、降低能耗以及成本等方面的挑战.本综述着重介绍MECs制氢的最新研究进展,首先扼要介绍了MECs技术制氢的工作原理和反应机理,总结并讨论了近几年电极材料、以及用于制氢的代表性电催化剂的研究进展,并且总结了不同有机物基底对MECs制氢性能的影响,最后提出了MECs制氢技术研究面临的几个关键挑战,展望提高MECs制氢性能的潜在方法.     

微生物电解池制氢研究进展

微生物电解池(MECs)是一种以微生物为电解制氢电池的阴极或阳极催化剂，将有机物间接转化为氢气的新型高效节能制氢技术. 此类可再生制氢技术的开发，仍面临如何提高制氢速率、降低能耗以及成本等方面的挑战. 本综述着重介绍MECs制氢的最新研究进展，首先扼要介绍了MECs技术制氢的工作原理和反应机理，总结并讨论了近几年电极材料、以及用于制氢的代表性电催化剂的研究进展，并且总结了不同有机物基底对MECs制氢性能的影响，最后提出了MECs制氢技术研究面临的几个关键挑战，展望提高MECs制氢性能的潜在方法.     

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.     

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.     

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.