一次多层云系云物理垂直结构探测研究

利用飞机PMS探测数据、雷达回波资料和FY-2卫星云图,分析了2009年6月四川盆地上空一次未形成地面降水的多层云系。结果表明,云系为Cs-As2-As1-Sc2-Sc1结构,夹有干层。云系中暖层厚,过冷层很薄。液态含水量随高度分布很不均匀,出现多个峰值。云系中液态含水量主要由小云粒子浓度决定,并且存在大量的小云滴、一...     

利用Ka波段毫米波雷达功率谱反演云降水大气垂直速度和雨滴谱分布研究

利用中国气象科学研究院2016年华南云降水试验中Ka波段毫米波雷达探测一次层状云降水过程,开展了云内大气垂直速度和雨滴谱的反演研究,并与地面激光雨滴谱仪和微降水雷达的测量雨滴谱结果进行对比分析。首先,采用小粒子示踪法从功率谱密度中反演大气垂直速度以得到静止空气条件下的功率谱密度,进而利用粒子下落末速度-粒子直径关系反演出雨滴谱,最后进行标准化的Gamma分布拟合。研究表明:(1)云降水从零度层到地面1 km,主要由下沉气流主导,近地面大气浮游粒子和直流干扰造成的晴空杂波会影响雷达的功率谱分布;受动态范围限制,回波强度过饱和现象会影响近地面大气垂直速度的反演结果;(2)毫米波雷达CR、微雨雷达MRR和地面雨滴谱仪测量回波强度存在一定差异,MRR相较于CR与地面雨滴谱仪测量偏差较小;在稳定降水时CR和MRR功率谱密度对比较为一致;(3) CR和MRR反演雨滴谱对比实验中,雨滴谱反演对大气垂直速度十分敏感,大气垂直速度的变化,会使CR反演雨滴谱随着高度增加数浓度量级变大、粒子平均半径变小。CR反演的雨滴谱与M RR反演结果基本一致,验证了CR功率谱反演雨滴谱方法的可靠性;(4) CR与地面雨滴谱仪雨滴谱拟合参数的对比表明,CR大气垂直反演的雨滴谱与地面雨滴谱相比粒子平均直径Dm较小,数浓度则较为一致。     

超高效液相色谱-串联质谱法直接进样测定水样中8种有机污染物

2011年我国实施了新的生活饮用水卫生标准,卫生指标扩展至106项,并配套了相关的检测方法,其中微囊藻毒素、莠去津采用液相色谱紫外检测器的检测方法;丙烯酰胺、灭草松、2,4-D采用气相色谱-电子捕获检测器的检测方法;呋喃丹、草甘膦采用液相色谱荧光检测器的检测方法。这些检测方法均有前处理程序繁琐、工作量大、可操作性差的缺点,在实际工作中应用较为困难。本文采用超高效液相色谱-串联质谱技术（UPLC-MS/MS）,建立了水样过0.22 μm滤膜,直接进样测定自来水、地下水及地表水中8种有机污染物（草甘膦、呋喃丹、灭草松、莠去津、2,4-滴、丙烯酰胺、微囊藻毒素-RR和微囊藻毒素-LR）的分析方法。8种化合物在各自的线性范围内线性关系良好,相关系数均不低于0.993,定量下限为0.07~5 μg/L,低、中、高三个加标水平的回收率为94.2%~103.7%,相对标准偏差为1.1%~7.8%。本文建立的方法操作简便,可以实现在6 min内一次性分析8种目标化合物,与国家标准方法相比,显著提高了分析效率;与文献报道的均是单一类化合物检测方法相比,本检测方法具有相似的灵敏度和检测限,但是目标化合物覆盖更全面,分析时间更短。     

福建地震地下流体工作的现状与展望

福建地下流体工作主要存在观测水点监测能力退化、监测队伍建设有待加强 ,学科管理相对滞后三方面问题。“十五”期间福建地震地下流体观测技术的发展方向 :1 井网布局以优化为主 ,注意控制台网的整体规模 ;2 提高现有骨干台站的综合观测能力 ;3 加强流体“气”、“热”及物理意义较明确的测项方面的实验研究观测。     

溶液结构的同步辐射反射法研究——径向分布函数解析

报道由硫酸钠水溶液实验径向分布函数通过理论模型计算,解析溶液结构参数的方法。其中包括建立理论结构模型的基本依据,专用KURLVR程序使用和结构参数最小二乘精修,以及高斯多峰拟合等实用方法,最终给出能够阐述溶液本质的微观结构参数。结果表明,硫酸钠溶液中水合Na+有2个水合层,第一水合层Na+-OH2(I)距离为0.243 nm,配位数6.0;第二水合层距离为0.448 nm,配位数为13.3;SO2-4存在第一水合层,SO2-4-H2O距离为0.374 nm,配位数为9.1;水合硫酸根原子团中氧原子与水分子的作用距离和配位数按OS-W(1)、OS-W(2)、OS-W(3)、OS-W(4),距离依次为0.283、0.322、0.375和0.486 nm,配位数除OS-W(2)为12.9,其余都在8左右;除此之外溶液中还存在NaOSO-3接触离子对,Na-S距离为0.348 nm,配位数0.20,与晶体结构比较证实SO2-4以单齿形式配位到Na+;水共享离子对Na+-W-SO2-4中Na-S距离精修为0.491 nm,配位数0.62。精修的R因子为0.16,表明获得了很好的精修结果。     

Aqueous mineral carbonation of serpentinite on a pilot scale: The effect of liquid recirculation on CO2 sequestration and carbonate precipitation

Following the promising results obtained on the laboratory scale, an aqueous mineral carbonation process was tested under industrial conditions as part of a pilot project conducted in a cement plant in Quebec. Experiments were conducted using a Parr 18.7 L reactor with cement plant flue gas (14–18 vol.%CO₂) and serpentinite tailings as a source of magnesium. The gas was not concentrated or separated before use. The reactions occurred at a solid/liquid ratio of 150 g/L, 22 ± 3 °C and a total pressure between 2 and 10 bar. To decrease water consumption, the effect of liquid recirculation on the rates of CO₂ sequestration, Mg leaching and carbonate precipitation were studied. The solid reacted with 6 successive batches of gas (15 min each), and the liquid was recovered for the carbonate precipitation after every two batches. For the recirculation assays, after carbonate filtration, the liquid was reused with subsequent batches.The results showed that the dissolution of CO₂ was not affected by the liquid recirculation since 72.5% of the CO₂ introduced was dissolved; in comparison to 77% when fresh liquid was used. The captured CO₂ resulted in 0.215 and 0.211 g CO₂/g of residue in the experiments with and without liquid recirculation, respectively. This result corresponds to approximately 45% of serpentinite's total capacity for CO₂ sequestration, which is 0.47 g CO₂/g of residue. The carbonate precipitation experiments were conducted in a separate system at low temperatures (32–40 °C) and included 2 h of stirring. When the liquid was recirculated, supersaturation was reached more quickly because of the accumulation of Mg²⁺ and HCO₃⁻/CO²⁻₃ ions. Therefore, the rate of precipitation and the amount of carbonate formed were significantly more important when the liquid was recirculated. However, the overall efficiency corresponding to the captured CO₂ under carbonate form does not exceed 9% even with liquid recirculation.     

液氯运输过程中的环境风险评价

从液氯运输过程中的风险因子和环境因素的识别出发,对液氯运输过程中可能存在的风险进行了分析,并采用L.E.C模式对存在的环境风险进行评价,提出了相应的预防措施。     

Latitudinal distribution of temporary liquid cryobrines on Mars

Simulations of the surface temperature and atmospheric humidity with a modern Mars climate model (MCD) and with Phoenix data are used to study the conditions for a liquefaction of brines as a function of latitude and season. The results show that, in the presence of appropriate salts, liquid cryobrines can in course of the diurnal cycle temporarily evolve at high latitudes on Mars’ current climate. The conditions for the liquefaction of “Mars-relevant” cryobrines and time and duration of their stability during the diurnal cycle are calculated for northern spring and for the Phoenix landing site.     

Axisymmetric liquid block impact on a solid surface

The hydrodynamic problem of collision of an axisymmetric water block and solid boundary has been analyzed based on the velocity potential theory. The three dimensional axisymmetric hydrodynamic problem is converted to a quasi two dimensional one and is solved in axisymmetric coordinate system using the boundary element method. Numerical simulations are made for collision of a solid cone with a liquid cone or a spheroidal liquid block. The results in the former are compared with those obtained from similarity solution and excellent agreement is found. Numerical results are then presented for the collision between different solid cones and various spheroidal liquid blocks.