单分散催化剂成冰机理的实验研究

Seeding agent is the key of weather modification around the world, and the nucleating effectiveness is the most important factor of all the chemical and physical characteristics of the seeding agents. How to output more high effective ice-nuclei from the seeding agents is the major direction of the research about the seeding technology. The spectrum of artificial ice-nuclei aerosols from seeding agents is a very wide spectrum, and it was never been done the experimental investigations on them by the conception of mono-dispersed aerosols before. In our project we plan to do the experimental research about mono-dispersed ice-nuclei aerosol in the useful range from 0.01 to 10.0μm. We will filter several different kinds aerosols from burning seeding agent by the DMA in the range from 0.05 to 0.5μm, and then do the research of their nucleation mechanism and testing in the cloud chamber. At the same time, we will investigate the aerosol physical and chemical properties by the instruments including Environment Scanning Electronic Microscope (ESEM) 6701F, Microcamera system, Infrared Thermometer, and so on. Our research will be most focused on the physical characters of aerosol particles and their nucleating mechanisms, especially for mono-dispersed. Though these experimental investigations, we wish get the optimal range in the useful artificial ice nuclei, and then improve our seeding agent based on our theory from our study. .This research is very important to both the field operation and experiments， and it is one of realistic meaning works to weather modification in our country.

催化剂成冰性能是云物理和人工影响天气研究的重要内容，想方设法产生尽量多有效人工冰核是催化剂配方改进的主要方向。催化剂产生的是一个分布较宽的多分散系气溶胶，对此人们已有所认识，但单分散冰核气溶胶的成冰性能又是如何？由于仪器和设备限制，以前从未开展过系统地实验研究。本项目拟在人工冰核气溶胶范围中，通过DMA等仪器获得不同粒径的单分散冰核气溶胶源，引入过冷云雾环境的云室中开展成冰特性和核化实验。结合环境场扫描电镜、显微摄像、红外测温等仪器开展单分散人工冰核气溶胶的颗粒表征、组分分析以及成冰核化机制机理研究。通过实验以期得到人工冰核的最佳单分散粒径范围。据此，提出催化剂改进的方向，并结合改变催化剂配方组分比例和调整制造加工工艺等手段，研制新型高效催化剂。该项工作将对加深人工冰核成冰核化理论认识和提高人影外场试验及作业水平两方面都具有重要现实意义。

课题针对我国人影作业和外场试验中使用催化剂的成冰机理进行研究。含AgI催化剂目前仍是最主要作业剂型，近年来不同厂家开展了配方改进，但成核率提高不多。本课题就是希望通过单分散催化剂成冰实验研究，深入认识催化剂产生人工冰核粒子的物化特征和成冰原理，为改进催化剂配方，有效提高其成核率提供科学理论依据。确定采用DMA的方式获取不同粒径单分散反应气溶胶，然后引进过冷雾的云室环境中实验，同时结合电镜和能谱仪对反应气溶胶的物化特征进行分析。. 结果表明，新研制配方WMC-IN-001和WMC-IN-002具有较高成核率，在-15℃时达到1015ｇ-1 AgI量级，尤其在-7℃时WMC-IN-001的成核率仍可达到1014ｇ-1 AgI量级有效提高高温段成冰能力。对比节银剂配方和2011年业务检测的5种催化剂的检测结果，WMC-IN-001和WMC-IN-002的成冰速率较慢，不同温度的成冰速率差异较小，均在40-55min。利用冷场发射扫描电镜和能谱仪对WMC-IN-001燃烧产生的气溶胶粒子作了物化特征分析，发现粒子分布在0.02～0.60µm，具有两个典型模态：0.02～0.10µm的较小的粒子和0.20～0.55µm的较大的粒子，均立方直径为0.2472µm。WMC-IN-001气溶胶粒子明显偏大，小粒子相对较少，这可能是其成冰速率偏慢的原因之一。. 爆炸实验：两炮弹成核率检测拟合值量级均为109～1012g-1 AgI（检测温度-6℃至-20℃），样品２成核率明显高于样品１。比较发现，两样品在负温高温段的成核率值均高于历史检测结果，其中在具有指示意义的-10℃下的成核率，两样品均比历史结果要高2～3个量级。实验成核率结果存在较大差异说明，采用同一平台开展统一检测十分必要。另外，不同AgI含量的实验结果表明，改变37人影弹AgI含量可以有效提高成核效率。由于仪器故障返修原因，分段分散催化剂的成核率实验完成较晚，实验数据正在处理中，其结果将整理发表。