基于激光光谱法的尿素水溶液液膜多参数测量

在选择性催化还原（SCR）系统中，对尿素水溶液液膜多个参数（厚度、浓度及温度）进行高精度的定量分析，对减少液膜形成、提高SCR系统的催化反应效率、降低NO_x对环境的污染至关重要。基于比尔-朗伯定律，通过结合1420 nm和1488 nm两个波长的半导体激光器，提出一种恒温度条件下尿素水溶液液膜厚度和浓度同步测量，以及恒浓度条件下尿素水溶液液膜厚度和温度同步测量的新方法。并在此基础上，利用标准具验证了该方法的测量精度。结果表明恒温度条件下，该方法同步测量尿素水溶液液膜厚度和浓度的平均测量误差分别为0.82%和3.93%；恒浓度条件下，同步测量尿素水溶液液膜厚度和温度的平均测量误差分别为0.79%和2.58%。     

基于激光光谱法的尿素水溶液液膜多参数测量

在选择性催化还原(SCR)系统中,对尿素水溶液液膜多个参数(厚度、浓度及温度)进行高精度的定量分析,对减少液膜形成、提高SCR系统的催化反应效率、降低NO_x对环境的污染至关重要。基于比尔-朗伯定律,通过结合1420 nm和1488 nm两个波长的半导体激光器,提出一种恒温度条件下尿素水溶液液膜厚度和浓度同步测量,以及恒浓度条件下尿素水溶液液膜厚度和温度同步测量的新方法。并在此基础上,利用标准具验证了该方法的测量精度。结果表明恒温度条件下,该方法同步测量尿素水溶液液膜厚度和浓度的平均测量误差分别为0.82%和3.93%;恒浓度条件下,同步测量尿素水溶液液膜厚度和温度的平均测量误差分别为0.79%和2.58%。     

管内垂直下降液膜速度与厚度分布特性

对洗涤冷却管内垂直降膜的流动特性进行研究,采用超声波多普勒测速仪对管内不同周向以及轴向位置的液膜厚度和速度进行了无接触式的测量,液膜Reynolds数范围为1.0×10⁴~3.1×10⁴。结果表明:在0°周向位置上液膜厚度与速度均达到最大值,导致该位置局部液膜厚度过大而不能保持稳定,部分液体脱离液膜表面,此外还造成了8°和16°位置的液膜厚度激增。在轴向上,当Reynolds数小于2.0×10⁴时,液膜速度在重力作用下随流动距离增加而增加,反之,液膜速度因为流动阻力会随距离增加而减小。随着Reynolds数的增大,液膜平均厚度和速度呈增大趋势。此外,Reynolds数的增大还会使得液膜更加不稳定。     

超声脉冲反射法和激光吸收光谱法同步测量流动液膜厚度

液膜流动现象在工业过程中广泛存在,对流动液膜厚度测量方法的测量研究至关重要。首先利用已知液膜厚度的标准具（100～1000 μm）对超声脉冲反射法和激光吸收光谱法精度进行验证;结果表明,超声脉冲反射法测量液膜厚度的平均测量误差为1.07%,激光吸收光谱法测量液膜厚度的平均测量误差为1.29%。同时结合两种方法对流动液膜进行研究,结果表明,当液膜在低速/中速/高速流动时,两种方法测量流动液膜的平均厚度吻合良好,平均厚度差值分别为16.59、16.26、13.36 μm,流动液膜厚度的标准方差的相对偏差分别为0.29%、7.71%、25.37%,且在三种不同速度下两种方法测得在1s的周期内液膜波动次数一致。     

超声脉冲反射法和激光吸收光谱法同步测量流动液膜厚度

液膜流动现象在工业过程中广泛存在,对流动液膜厚度测量方法的测量研究至关重要。首先利用已知液膜厚度的标准具(100~1000μm)对超声脉冲反射法和激光吸收光谱法精度进行验证;结果表明,超声脉冲反射法测量液膜厚度的平均测量误差为1.07%,激光吸收光谱法测量液膜厚度的平均测量误差为1.29%。同时结合两种方法对流动液膜进行研究,结果表明,当液膜在低速/中速/高速流动时,两种方法测量流动液膜的平均厚度吻合良好,平均厚度差值分别为16.59、16.26、13.36μm,流动液膜厚度的标准方差的相对偏差分别为0.29%、7.71%、25.37%,且在三种不同速度下两种方法测得在1s的周期内液膜波动次数一致。     

中空纤维空气隙式膜蒸馏海水淡化过程的性能模拟与优化

利用响应曲面法(RSM),以模拟标准海水(质量分数3.5%)为进水对中空纤维空气隙式膜蒸馏(AGMD-HF)海水淡化过程的影响因子和膜通量指标进行了模拟优化。通过面向中心复合设计法(CCD)实现了基于热料液进水温度、冷凝液进水温度和料液流量的实验优化设计,并建立了响应值与影响因子之间的二次多项式回归模型。方差分析(ANOVA)、RSM分析及实验响应值与预测值的对比验证了该模型对影响因子和膜通量模拟优化的可信度。进一步地,通过期望函数的引入确定了各影响因子最佳水平,并利用太阳能加热驱动过程实验进行验证。结果表明,ANOVA的决定系数R²达到0.986,p值则低于0.0001;实验膜通量与预测值平均误差仅为6.95%,产水电导率始终保持在10 μS·cm^-1以下,脱盐率稳定在99.99%以上;最佳影响因子水平分别为83.5℃、13.2℃和60.2 L·h^-1,在此条件下太阳能加热驱动过程膜通量达到6.47 L·m^-2·h^-1。该实验不仅为潜在可行的规模放大过程提供了可参照的操作参数,而且表明将太阳能引入AGMD-HF海水淡化过程具有很强的实际应用潜力。     

动态液膜厚度测试技术的研究

本文介绍了一种灵敏度高、适用性强的动态液膜厚度测试装置;能连续测定动态液膜厚度的波动曲线,液膜厚度与它所对应的记录曲线的振幅高度成正比,利用这一关系使该装置的标定方法简单且测量精度较高,在1mm左右的测量范围内其误差不大于2.2%,利用该装置测量气-液环状两相流的液膜厚度,取得了较好的结果.     

苯乙烯磺酰氯的理论模拟及用于辐照接枝法制备质子交换膜

合成了用于辐照接枝制备质子交换膜的对苯乙烯磺酰氯单体,并采用红外光谱（FTIR）、核磁共振氢谱（¹H NMR）和核磁共振碳谱（¹³C NMR）对其结构进行了表征分析,分析结果表明：成功得到了目标产物对苯乙烯磺酰氯。基于密度泛函的量子化学方法对合成的单体进行了理论模拟,结果表明该单体具有与苯乙烯一致的电荷分布,乙烯基α碳位易发生亲电反应,β碳位易发生亲核反应和自由基反应。采用辐射接枝聚合的方法,将对苯乙烯磺酰氯单体接枝到聚全氟乙丙烯薄膜基材上并通过后处理制备用于燃料电池的质子交换膜,结果表明膜的质子传导率与接枝率正相关,在20 Gy·min^-1和40 Gy·min^-1条件下膜的室温质子传导率分别为45.74 mS·cm^-1和47.46 mS·cm^-1,20 Gy·min^-1条件下制备的质子交换膜其传导率在75℃时可达84.56 mS·cm^-1。     

正渗透膜污染影响因素的研究与分析

以海藻酸钠（ALG）为典型有机污染物,采用TFC FO膜,以水通量下降率和污染阻力作为膜污染的评价指标,探究了正渗透（FO）过程中的膜摆向（FO模式和PRO模式）、原料液（FS）和驱动液（DS）的浓度、原料液中Ca²⁺浓度和pH对FO膜污染的影响规律,并提出适宜的膜清洗方案。结果表明,在PRO模式下,膜污染阻力为3.38×10¹¹m^-1,而在FO模式下仅为3.88×10¹⁰m^-1,表明FO模式污染轻;FS或者DS浓度的增大均会导致污染阻力增大,使得污染更加严重;当FS中不含Ca²⁺和含Ca²⁺浓度分别为1mmol/L和2mmol/L时,相较于初始通量,其通量降低率分别15.40%、18.49%和24.93%,当Ca²⁺浓度从1mmol/L增大到2mmol/L过程中,膜污染阻力增大1.6倍;当FS的pH为4.2、7.0和10.7时,水通量降低率依次增加,分别为14.56%、14.82%和18.78%。分别采用去离子水、pH为3.0的HCl溶液、pH为11.8的NaOH溶液以及十二烷基硫酸钠（SDS,pH=11.0）溶液对膜进行清洗,得到SDS溶液清洗效果较好,通量恢复率可达90.70%。     

含氟聚芴醚二唑质子交换膜的性能

将十氟二唑和双酚芴作为聚合物单体制备了一种新型的偏氟聚芴醚二唑质子交换膜。通过加入4-羟基磺酸钠进攻十氟二唑邻位的C-F键引入官能基团探究了膜的制备方法。研究了膜的物理、电化学性能并组装了燃料电池单电池。实验结果表明:该膜具有较高的离子传导率、较强的机械性能及低的甲醇渗透率。30℃时,传导率为58 mS·cm^-1,70℃,传导率达到了137 mS·cm^-1。甲醇渗透率是Nafion^® 117膜的1/2,在100℃时,单电池的功率达到85 mW·cm^-2。     

氨缓冲体系强化高纯重质碳酸锰的制备

以碳酸钠和高纯硫酸锰为原料,通过共沉淀法在氨缓冲溶液中制备高纯重质碳酸锰。当硫酸锰和碳酸钠溶液浓度都为1.5 mol·L^-1、碳酸钠过量系数为110%、溶液pH为8.5、温度为50℃、滴加速率为120 ml·h^-1时,得到的碳酸锰视密度达1.67 g·cm^-3,振实密度达2.15 g·cm^-3。氨缓冲体系增加了溶液的稳定性,抑制了溶液中氢氧化锰和偏氢氧化锰的生成,制备出的高密度碳酸锰形貌趋于球形,粒径分布均匀,D₅₀平均大小为30.32 μm。以本研究制备的碳酸锰为锰原料焙烧得到的四氧化三锰松装密度为1.09 g·cm^-3,振实密度为2.18 g·cm^-3,锰的含量可达71.85%。     

Effect of imidazole based polymer blend electrolytes for dye-sensitized solar cells in energy harvesting window glass applications

The exploration of polymer electrolyte in the field of dye sensitized solar cell (DSSC) can contribute to increase the invention of renewable energy applications. In the present work, the influence of imidazole on the poly (vinylidene fluoride) (PVDF)-poly (methyl methacrylate) (PMMA)-Ethylene carbonate (EC)-KI-I₂ polymer blend electrolytes has been evaluated. The different weight percentages of imidazole added into polymer blend electrolytes have been prepared by solution casting. The prepared films were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), UV-visible spectra, photoluminescence spectra and impedance spectroscopy. The surface roughness texture of the film was analyzed by atomic force microscopy (AFM). The ionic conductivity of the optimized polymer blend electrolyte was determined by impedance measurement, which is 1.95×10^-3 S·cm^-1 at room temperature. The polymer electrolyte containing 40 wt% of imidazole content exhibits the highest photo-conversion efficiency of 3.04% under the illumination of 100 mW·cm^-2. Moreover, a considerable enhancement in the stability of the DSSC device was demonstrated.     

QUASI-SOLID-STATE DYE-SENSITIZED SOLAR CELLS BASED ON ZnO PHOTOANODE

ZnO photoanode in dye-sensitized solar cells (DSSCs) has been successfully prepared by the electro-hydrodynamic (EHD) technique. The sandwich solar cells exhibited a short-circuit photocurrent density of 7.0 mA cm^-2 and conversion efficiency of 1.65% with a quasi-solid-state electrolyte under simulated sun illumination (AM-1.5, 100 mW cm^-2). The stability and the influencing factors, such as film thickness and light intensity, on solar cell performance were discussed.     

反气相色谱法与汉森溶解度参数软件测定原煤的三维溶解度参数

采用反气相色谱法（IGC）研究原煤在温度433.15、443.15、453.15、463.15和473.15 K时的三维溶解度参数（HSP）,并使用外推法得到原煤室温（298.15 K）时HSP的色散力分量（δ_d）、极性力分量（δ_p）、氢键力分量（δ_h）以及校正溶解度参数（δ_t）分别为δ_d=20.83（J·cm^-3）^1/2,δ_p=11.95（J·cm^-3）^1/2,δ_h=11.08（J·cm^-3）^1/2,δ_t=26.44（J·cm^-3）^1/2。同时,采用汉森三维溶解度参数软件（HSPiP）模拟原煤在室温下的HSP,得到δ_d=19.92（J·cm^-3）^1/2,δ_p=11.18（J·cm^-3）^1/2,δ_h=11.47（J·cm^-3）^1/2,δ_t=25.56（J·cm^-3）^1/2。IGC与HSPiP得出的数据一致,研究结果为煤的热力学性质研究及其溶胀剂的选择等应用提供了参考。     

Electronic absorption spectrum of Co2 ions doped in lithium caesium sulphate single crystal

Single crystals of Lithium Caesium Sulphate doped with Co²⁺ ions were grown by slow evaporation of an aqueous solution of Lithium Sulphate and Caesium Sulphate to which Cobalt Sulphate is added as dopant. Electronic absorption spectra have been recorded at room and liquid nitrogen temperatures on Cary-17 Spectrophotometer. When the crystal is cooled to liquid nitrogen temperature changes in intensity and band position are observed and some of the bands are splitted. From the nature and position of the bands a successful interpretation of all the observed bands have been made and identified as those belonging to Co²⁺ ion in an octahedral crystal field. The crystal field parameters derived for room temperature are Dq = 870 cm^-1, B = 900 cm^-1 and C = 3150 cm^-1 and for liquid nitrogen temperature are Dq = 880 cm^-1, B = 900 cm^-1, C = 3150 cm^-1 and ζ = 500 cm^-1.     

MEASUREMENT OF LIQUID FILM THICKNESS ON THE SURFACE OF A PARTIALLY IMMERSED VERTICAL ROTATING DISK USING A GAMMA CAMERA

The liquid film thickness on the surface of a partially immersed vertical rotating disk was determined using a gamma camera imaging system to measure the amount and spatial distribution of a dissolved 99m-Technetium pertechneiate radionuclide tracer. The method allows simultaneous measurement of film thickness in individual regions having a projected surface area of less than 1 cm² and distributed over the entire exposed surface of the disk. Measurement accuracy is limited only by counting statistics, and for these studies was better than ±4% of the absolute film thickness.

Experiments were conducted with a 31.5 cm diameter aluminum disk rotating from 18 to 99 revolutions per minute; seven aqueous solutions of glycerol and polyvinylpyrrolidone (PVP) within the viscosity range 1 to 19.7 cp were used. The average film thickness varied between 0.045 and 0.45 mm, and was a function of solution viscosity and disk angular velocity. Local film thickness was dependent on both radial and angular position, and varied from 0.5 to 3.0 times the average thickness. This variation may be important to the characterization of mass transfer when diffusion through the film is a rate limiting step     

Homogeneous Co3O4 film electrode with enhanced oxygen evolution electrocatalysis via surface reduction

Homogeneous NaBH_4-reduced Co_O_4 thin film electrodes with enhanced oxygen evolution electrocatalysis were obtained via a controlled-synthesis route.Firstly CoOx colloids were synthesized via ethylene glycol solvothermal method and cast on conductive glass substrates.The oxygen evolution reaction(OER) electrocatalysis of these asprepared Co_3O_4 thin films were then significantly enhanced via a simple surface reduction by NaBH_4 solution.The OER catalytic performance of the NaBH_4-reduced thin films was strongly dependent on the NaBH_4 concentration.The use of NaBH_4-reduced thin film electrodes for OER in alkaline solution supported higher current density and consequently negative shifts of the onset potential compared to that of the pristine.The optimal B_(12.5,20)-Co_3O_4 thin films exhibited excellent OER catalytic performances:At the current density of 10 mA·cm~(-2),a low overpotential of 365 mV and a small Tafel slope of 59.0 mV·dec~(-1) were observed.In addition,these B_(12.5,20)-Co_3O_4 thin film electrodes possessed good stability that can well recover its OER performance in a 24-h chronoamperometric stability test.     

锑离子添加剂对低共熔溶剂(DES)电解液液流电池的性能改善研究

非水系氧化还原液流电池（NARFB）的广泛应用受制于其较低的性能。在电解液中加入一些金属离子添加剂是一种可能的解决方案。实验研究了Sb³⁺离子对低共熔溶剂（DES）电解液液流电池电化学性能的影响。结果表明,添加Sb³⁺离子可以强化V（Ⅲ）/V（Ⅱ）氧化还原离子对的电化学反应动力学（最高可达22.6％）过程,钒离子在DES中的扩散系数提高了63.3％,并且电荷转移电阻降低了11.9％。场发射扫描电子显微镜表明,Sb³⁺离子电沉积在石墨毡的表面,对电化学反应起催化作用,从而改善了电化学性能。考虑增强的动力学和降低的活性比表面积之间的平衡,确定了Sb³⁺的最佳浓度为15 mmol·L^-1。此外,当使用含有Sb³⁺的负极电解液液流电池时,液流电池的功率密度提高了31.2%,从含原始电解质的3.08 mW·cm^-2到含15 mmol·L^-1 Sb³⁺离子的4.04 mW·cm^-2。这些结果为改善NARFB的电池性能提供了一个便捷而有前景的方法。     

锌-空气电池电解液Zn2+浓度对析氢过程的影响

水溶液体系的二次金属-空气电池通常具有安全环保的特点,但是充电过程中仍然存在析氢副反应的安全隐患。使用线性电势扫描方法、Tafel极化曲线及极限扩散电流密度参数定量分析了二次锌-空气电池体系电解液中Zn²⁺浓度对析氢反应过程的影响。结果表明,随着电解液中Zn²⁺浓度的提高,析氢过电势逐渐增大,Zn²⁺浓度在6 mol·L^-1 KOH溶液中达到0.4 mol·L^-1时,析氢过电势超过2.42 V,析氢过电势比空白溶液提高1.2 V,并且Tafel极化曲线的截距超过1.5 V,析氢电势达到超高过电势范围。此外,由Zn²⁺提供的极限扩散电流密度提高至8.9 A·cm^-2,所对应的过电势提高700 mV。研究结果对于确立二次锌-空气电池极限充电范围提供定量依据,对电池安全平稳运行具有重要价值。     

Electronic absorption spectrum of Co2 ions doped in potassium dihydrogen phosphate single crystal

Single crystals of Potassium dihydrogen phosphate doped with Co²⁺ ions were grown by slow evaporation at room temperature from a saturated solution of Potassium dihydrogen phosphate to which 0.5 mole percent of Cobalt phosphate was added as an impurity, Electronic absorption spectra have been recorded at room and liquid nitrogen temperatures on Cary - 2390 Spectrophotometer. When the crystal is cooled to liquid nitrogen temperature, changes in intensity and band position are observed and some of the bands are splitted. From the nature and position of the bands, a successful interpretation of all the observed bands have been made and identified as those belonging to Co²⁺ ion in an octahedral crystal field. The crystal field parameters derived for room temperature are Dq = 860 cm^-1, B = 920 cm^-l and C = 3680 cm^-1 and for liquid nitrogen temperature are Dq = 870 ^cm-l, B = 920 cm^-1, C = 3680 cm^-l and S = 500 cm^-1.