探测对流层底部CO2廓线振动拉曼激光雷达定标实验

基于振动拉曼散射原理,研制了可探测对流层底部大气CO₂浓度分布的激光雷达系统,结合三维光学扫描系统的使用,该激光雷达具备了三维扫描功能,能够实现大气CO₂浓度的空间分布监测. 结合该激光雷达能够实现三维扫描的特点,提出了振动拉曼激光雷达新的定标方法,开展了激光雷达定标实验,实现了该雷达系统的准确定标,从而获得了合肥地区CO₂廓线结果. 对提出的定标实验结果的不确定性进行分析,得出该方法的不确定度为1%,证明了该定标实验方法的可靠性.      

高精度F-P干涉具在CO2浓度反演中的研究

为了对大气中CO₂浓度的分布进行高精度的实时监测,并与被测区域2维图像构成光谱数据立方,设计了一种基于高精度数字控制的F-P干涉系统.通过对F-P两镜间微位移的高精度数字控制,实现光程差的周期性扫描,从而得到光谱数据立方.通过仿真分析了控制命令与压电信号的时序逻辑,并对光谱抽样进行了模拟计算.实验中系统的光谱调制带宽为761.52～762.56 nm,光谱分辨率为0.01 nm,测试CO₂浓度范围为10～400 ppm,由TSI-7575型高精度CO₂检测器标定.结果显示:该系统相对误差的平均值为1.04%,绝对误差平均值为1.52 ppm,符合设计要求.     

基于光谱吸收的CO2气体检测系统

针对CO₂气体实时在线监测的应用需求,以比尔-朗伯定律为理论基础,基于可调谐半导体激光吸收光谱技术搭建一套CO₂气体在线检测系统。选择吸收谱线波长为1 609.583 nm,并在系统中搭建两路参考光路用于消除光源信号波动和实现自动寻峰,以提高检测系统的稳定性与准确性。通过对系统的标定与校准,系统测量相对误差小于0.8%,系统重复性小于0.06%,响应时间不超过18 s,对空气中CO₂的体积分数进行连续4 h监测,其值的波动范围为360×10^-6 ~ 400×10^-6。试验结果表明该系统具有较好的稳定性与可靠性,可满足CO₂气体实时在线监测的应用需求。     

南海碳循环：通量、调控机理及其全球意义

 基于多年观测研究,南海CO₂源汇及其时空格局的总体特征是：南海海盆是大气CO₂的弱源区,年均海-气CO₂通量为2.1±0.3 mmol·m^-2·d^-1;而南海北部陆架是碳汇区,年均CO₂通量为-2.2±3.5 mmol·m^-2·d^-1;南海总体上每年向大气释放的碳量为1330万±1880万t。由于南海位于陆地-大洋交界带,存在多个界面过程,根据物质交换发生的不同界面,可将南海海盆和北部陆架视为大洋主控型边缘海（OceMar）和河流主控型陆架海（RiOMar）。这两类系统分别接受大洋和河流输入的外源无机碳和营养盐,经由一系列动力过程进入真光层后同时被生物消耗,无机碳和营养盐之间的“竞争”最终决定CO₂源汇格局。在南海海盆,无机碳相对过剩,部分以CO₂形式向大气释放,即为源;而在南海北部陆架,无机碳相对不足,系统需从大气补充CO₂,即为汇。南海碳循环机理及其框架对于更好地理解全球其他陆架边缘海系统具有重要的借鉴意义。     

CO2/HCs混合物宽区域黏度模型的热力学研究

 基于Vesovic-Wakeham理论,建立CO₂/HCs二元混合物黏度预测模型,对CO₂/CH₄,CO₂/C₂H₆,CO₂/C₃H₈,CO₂/n-C₄H₁₀和CO₂/iso-C₄H₁₀这5种重要CO₂/HCs二元体系的黏度进行了预测,温度范围为273.15～973.15 K,压力范围为0.1～200 MPa,最大黏度预测值达140 μPa·s。与大量文献实验数据的比较表明,所预测的黏度计算值具有较高的精度,可以满足工程应用的实际要求。     

基于碱法机理减少船舶CO2排放研究

提出了利用NaOH溶液吸收船舶CO₂的方法,分析了船舶CO₂回收机理,依据6135G128ZCa型船舶柴油机的特点,设计了船舶CO₂吸收系统,推导出船舶CO₂吸收效率数学模型.通过实例分析了NaOH溶液浓度变化、反应温度变化对船舶尾气中CO₂吸收效率的影响.验证了利用NaOH溶液吸收船舶尾气中的CO₂,能够有效降低船舶CO₂排放量20%以上,为未来船舶CO₂的减排技术奠定基础.      

Mg-MOF-74对CO2/CH4吸附分离的分子动力学模拟及气体吸附性能研究

天然气是一种环保型能源并且可被广泛用做化工原料，但是其中的CO₂会严重影响天然气的热值与输送性能，因此对天然气中的CO₂进行有效脱除尤为重要。选用Mg-MOF-74作为吸附剂，采用分子动力学模拟计算方法分析Mg-MOF-74对CO₂/CH₄吸附分离性能的影响。模拟计算结果显示，在一定的温度、压强条件下，CO₂比CH₄更容易与Mg-MOF-74的金属位点相结合，Mg-MOF-74对CO₂气体的相互作用力更强，从而证明Mg-MOF-74对CO₂的吸附能力也更好。为验证模拟结果的准确性，制备了Mg-MOF-74并测试了其CO₂/CH₄吸附性能，实验结果与模拟结果一致，证明Mg-MOF-74对CO₂有很高的选择性。     

森林土壤温室气体通量对森林管理和全球大气变化的响应

森林土壤是温室气体重要的源和汇。探讨不同森林管理和全球大气变化下土壤温室气体通量特征,为有效减少温室气体排放及森林可持续管理等提供参考。笔者从森林土壤温室气体(forest soil green house gases)、森林管理(forest mangement)和全球大气变化(global atmospheric change)3个关键研究点,查阅近年来相关研究成果,归纳森林管理和全球大气变化下土壤温室气体通量的一般性模式。CO₂、CH₄和N₂O是3种重要温室气体,其通量间存在协同、消长和随机型耦合关系。森林管理如火烧、采伐和造林等显著影响土壤温室气体通量。一般情况下,火烧导致土壤N₂O通量降低,CH₄吸收量增加,CO₂通量因火烧类型、火烧强度、生态系统类型不同出现增加、减低和无影响3种结果; 采伐通常导致土壤CO₂、CH₄和N₂O排放增加; 造林可使土壤CO₂排放减少,对N₂O和CH₄通量的影响随生态系统类型、造林树种等而改变。全球大气变化如CO₂浓度升高、氮沉降和气温升高影响森林土壤温室气体通量。通常,CO₂浓度升高导致土壤CO₂和N₂O排放量增加,CH₄吸收量降低; 氮沉降促进土壤N₂O排放、抑制CH₄吸收。气温升高导致土壤CO₂和N₂O排放增加。森林管理和全球大气变化对土壤温室气体通量的综合影响是非叠加的,有效的森林管理可能改变土壤温室气体通量对全球大气变化的响应。     

锆酸锂的合成及其吸收CO2性能研究

以纳米级四方相ZrO₂(t)为反应物,采用高温固相法合成了在高温下可直接吸收CO₂的Li₂ZrO₃材料。用扫描电子显微镜（SEM）、X-射线粉末衍射仪（XRD）分别分析了所合成材料的表面与结构特征,使用热重分析仪（TG）研究了Li₂ZrO₃材料吸收CO₂的性能。实验结果表明,吸收温度影响材料吸收CO₂的性能,500℃下Li₂ZrO₃材料具有最佳的CO₂吸收性能。此外,CO₂气体流量、Li₂ZrO₃材料样品重量以及升温速率均影响材料吸收CO₂的性能。     

小型米散射激光雷达系统设计

为了探测对流层内大气气溶胶和卷云的光学特性以及大气水平能见度等,在阐述了大气气溶胶探测原理及信号处理方法的基础上,利用二极管激光泵浦的Nd:YAG固体激光器的二倍频波长(532 nm)激光为光源,设计了一台小型微脉冲米散射激光雷达,并利用标准大气模型对系统进行了仿真计算。仿真结果表明,在探测误差小于10%条件下,系统在白天和夜晚的探测高度分别为6 km和13 km。该系统还具有对人眼安全、能全方位扫描探测等特点,可应用于城市及特定场合(如厂区,大型公共场所)的大气环境监测,也可用于沙尘暴探测及其预警预报技术的研究。     

基于植酸锆/普鲁士蓝复合膜的电催化行为研究

通过层层自组装技术,构建植酸锆/普鲁士蓝(Zr-IP_6/PB)多层结构膜.基于普鲁士蓝(PB)对双氧水(H_2O_2)有很高的电催化性能,加之5层植酸锆/普鲁士蓝膜多孔结构有利于传质过程,该H_2O_2传感器具有高灵敏度和高选择性.实验结果显示:修饰电极对H_2O_2响应的物质的量浓度范围为2.00×10~(-5)～1.76×10~(-3) mol·L~(-1),线性相关系数R=0.998 9.     

Frequency stabilization of Nd: YVO4 mini-laser using the third-harmonic detection

Via saturated absorption spectroscopy and the third-harmonic detection technique, the hyperfine spectra of ¹²⁷I₂ near 532 nm have been observed within the tuning range of a mini Nd︰YVO₄-KTP laser. The laser is frequency stabilized against one hyperfine structure (hfs) component of ¹²⁷I₂. The analysis of error signal shows that it is possible to realize a frequency stability of 3.0×10^-13 at 1 s average time.     

CuFe2O4纳米粒子增敏Luminol-EDTA化学发光体系研究及应用

基于CuFe_2O_4纳米粒子能显著增强Luminol-EDTA体系的发光,首次建立了Luminol-EDTA-CuFe_2O_4 NPs化学发光新体系。紫外吸收光谱和化学发光光谱表明纳米CuFe_2O_4注入Luminol-EDTA体系后,未生成新发光物质,结合纳米CuFe_2O_4的特性,提出了CuFe_2O_4 NPs参与Luminol-EDTA体系可能的发光机理。研究发现芦丁能抑制Luminol-EDTACuFe_2O_4 NPs体系的化学发光,结合流动注射技术,将此化学发光体系应用于芦丁片中芦丁含量的测定。在优化实验条件下,芦丁浓度在2×10~(-8)~2×10~(-5) mol/L范围内芦丁浓度的对数和相对化学发光值呈线性,芦丁浓度检出限(LOD)为1.21×10~(-9) mol/L。将本方法应用于芦丁片中的芦丁含量测定,回收率为97%~102%,RSD为2.54%(c=1×10~(-7) mol/L,n=11)。     

Changes of photosynthetic capacity of some plant species under very high CO2 concentrations in Biosphere 2

Conclusions The initial slope of A/ light curve became steep under high CO₂ (700 μmol · mol^-1) compared with that under low CO₂ (350 μmol · mol^-1) for the C₃ species growing in very high CO₂(>2 200 μmol · mol^-1) for a long period. The light compensation points remained unchanged, but the light saturation points were found increased. The ϕ_m,_app and A_max of the C₃ species increased respectively by 79 % and 80 %, while those of C₄ species decreased by 10% and 14%, respectively. The shape of A/light curve of C₄ species did not change. Such results indicated that C₃ species increased the capacity of photosynthesis, while C₄ did not change, otherwise it decreased a little. This work only compared the changes of capacity in photosynthesis of some species under different CO₂ levels in Biosphere 2. We need further investigation on the effects of high CO₂ on the same species outside Biosphere 2, in order to fully undertand the effects and mechanism of response of plants to the elevated CO₂.     

流动注射分析法测定水样中的NO2--N和NO3--N

采用流动注射技术测定水样中的NO-/2-N和NO-/3-N.以N-(1-萘基)乙烯二胺盐酸盐和对氨基苯磺酸为显色剂,在540nm下比色测定NO-/2-N的含量.水样中的NO-/3-N,在稀醋酸条件下用锌粉将其预还原成NO-/2-N后,也在上述相同的条件下测定其含量.NO-/2-N的检出限为0.005×10-/6,NO-/3-N的检出限为0.05×10-/6,分析速度为65次/小时.     

CO2的温室效应饱和度分析及其大气体积分数预测模型

通过精确的LBLRTM逐线积分模式建立CO_2体积分数变化模型,分析了CO_2的温室效应饱和度,并对未来地表温升的变化趋势进行了预测.结果表明,目前CO_2的持续排放只能使其在680cm~(-1)强吸收带中心达到饱和,而在未来相当长一段时间内,其仍将通过该吸收带的翼区以及1 000cm~(-1),1 350cm~(-1)与1 900cm~(-1)等弱吸收带对地表红外辐射表现出强烈的吸收,CO_2的温室效应还远未达到饱和;如果按照当前CO_22.2(mL/·m~(-3))/a的年排放速率,CO_2的大气体积分数将会持续增加,从而造成地表温度不断升高,到2056年,地表温升将会达到2K.     

Trend, seasonal and diurnal variations of atmospheric CO2 in Beijing

The concentration of atmospheric CO₂ in Beijing increased rapidly at a mean growth rate of 3.7% · a⁻¹ from 1993 to 1995. After displaying a peak of (409.7±25.9) μmol · mol⁻¹ in 1995, it decreased slowly. Both the almost stable anthropogenic CO₂ source and increasing biotic CO₂ sink contribute to the drop of CO₂ concentration from 1995 to 2000. The seasonal variation of CO₂ concentration exhibits a clear cycle with a maximum in winter, averaging (426.8±20.6) μmol · mol⁻¹, and a minimum in summer, averaging (369.1±6.1) μmol·mol⁻¹. The seasonal variation of CO₂ concentration is mainly controlled by phenology. The mean diurnal variation of atmospheric CO₂ concentration for a year in Beijing is highly clear: daily maximum CO₂ concentration usually occurs at night, but daily minimum CO₂ concentration does in the daytime, with a mean diurnal difference more than 34.7 μmol·mol⁻¹. It has been revealed that the interannual variations of atmospheric CO₂ concentration in winter and autumn regulated the interannual trend of atmospheric CO₂, whereas the interannual variation of CO₂ concentration in summer affected the general tendency of atmospheric CO₂ in a less degree.     

Investigation of the cross-reaction mechanism of C<Subscript>6</Subscript>H<Subscript>5</Subscript>F-HNO<Subscript>2</Subscript> aqueous solution irradiated at 355 nm by transient absorbance spectrum technique

The transient absorption spectrum technique was employed to investigate the cross-reaction mechanism of C6H5F-HNO2 aqueous solution irradiated at 355 nm. The characteristic and the kinetic parameters of transient species were also detected. Hydroxyl radical derived from the photolysis of HNO2 was added to monofluorobenzene with a second-order rate constant of （5.83±0.17）×10^9 L·mol^-1·s^-1 to form an adduct, C6H5F…OH, which was able to react with HNO2 as the main reaction pathway with a rate constant of （8.3±0.1）×10^7 L·mol^-1·s^-1. The C6F6…OH adduct can also be decayed by elimination of H2O to yield monofluorophenyl radical C6H4F-. By GC-MS technique, the final products were identified to be monofluorophenol, nitro-monofluorobenzene, nitro-monofluorophenol and para-fluorobiphenyl.     

Perovskite-type B-site Bi-doped ceramic membranes for oxygen separation

Novel mixed conducting oxides, B-site Bi-doped perovskites were exploited and synthesized.Cubic perovskite structures were formed for BaBi0.2CoyFe0.8-yO3-δ (y≤0.4) and BaBixCo0.2Fe0.8-xO3-δ(x=0.1-0.5).The materials exhibited considerable high oxygen permeability at high temperature.The oxygen permeation flux of BaBi0.2Co0.35Fe0.45O3-δ membrane reached about 0.77×10-6 mol/cm2.s under an air/helium oxygen partial pressure gradient at 900℃, which was much higher than that of other bismuth-contained mixed conducting membranes.The permeation fluxes of the materials increased with the increase of cobalt content, but no apparent simple relationship was found with the bismuth content.The materials also demonstrated excellent reversibility of oxygen adsorption and desorption.Stable time-related oxygen permeation fluxes were found for BaBi0.2Co0.35Fe0.45O3-δ and BaBi0.3Co0.2Fe0.5O3-δ membranes at 875℃.     

Stabilization of mini-Nd: YVO4 laser using I2 hyperfine transition

By using a diode-pumped Nd:YVO₄ / KTP intracavity frequency-doubling mini-laser and frequency modulation optical heterodyne spectroscopy, we have obtained spectrum of¹²⁷I₂ hyperfine structure near 532 nm. The laser frequency is locked to hyperfine transitions of I₂. The analysis of error servo signal demonstrates that the laser frequency stability can reach 10⁻¹² at 1 second average time.