自清洁材料的研究进展

针对自清洁材料的构筑方法进行系统整理和归纳,围绕自清洁表面亲疏水性不同(分为超疏水、超亲水、超疏水/超亲水可转变)、表面构筑机制不同进行分类阐述和总结,并对自清洁材料目前面对的困境提出发展设想。

The extreme dry/wet events in northern China during recent 100 years

Using monthly precipitation and monthly mean temperature, a surface humid index was proposed. According to the index, the distributed characteristics of extreme dryness has been fully analyzed. The results indicated that there is an obvious increasing trend of extreme dryness in the central part of northern China and northeastern China in the last 10 years, which shows a high frequency period of extreme dryness; while a low frequency period in the regions during the last 100 years. Compared with variation trend of the temperature in these regions, the region of high frequent extreme dryness is consistent with the warming trend in the same region.

Laser surface functionalization to achieve extreme surface wetting conditions and resultant surface functionalities

Wetting condition of micro/nanostructured surface has received tremendous attention due to the potential applications in commercial,industrial,and military areas.Surfaces with extreme wetting properties,e.g.,superhydrophobic or superhydrophilic,are extensively employed due to their superior anti-icing,drag reduction,enhanced boiling heat transfer,self-cleaning,and anti-bacterial properties depending on solid-liquid interfacial interactions.Laser-based techniques have gained popularity in recent years to create micro/nano-structured surface owing to their high flexibility,system precision,and ease for automation.These techniques create laser induced periodic surface structures(LIPSS)or hierarchical structures on substrate material.However,micro/nanostructures alone cannot attain the desired wettability.Subsequent modification of surface chemistry is essentially needed to achieve target extreme wettability.This review paper aims to provide a comprehensive review for both laser texturing techniques and the following chemistry modification methods.Recent research progress and fundamental mechanisms of surface structure generation via different types of lasers and various chemistry modification methods are discussed.The complex combination between the laser texturing and surface chemistry modification methods to decide the final wetting condition is presented.More importantly,surface functionalities of these surfaces with extreme wetting properties are discussed.Lastly,prospects for future research are proposed and discussed.

Extreme Adaptation to Extreme Environments in Hot Dry, Hot Sub-humid and Hot Humid Climates in Mexico

The paper discusses the results of a field study carried out in four cities in Mexico： Hermosillo, Mexicali, Merida and Colima, during the warmest seasons of 2006-2007. The survey is according to the adaptive approach of thermal comfort. The cities＇ climates are hot dry, hot sub-humid and hot humid. The respondents were inhabitants of low cost housings without air conditioning. The research was performed during warm seasons and according to ISO 10551. The measurements were processed by the common method of linear regression and also by alternative methods, useful for asymmetric climates. Individuals declared comfort at very high temperatures, either high or low humidity, therefore, the resulting neutral temperatures are higher than 30 ℃, except in Colima （28.8 ℃）. The upper limits of comfort ranges achieved temperatures up to 35 ℃. The results suggest how great is the capacity of humans to adapt to conditions as extreme as those measured in the study.

荒漠灌丛碳通量对极端水分和温度的响应研究

利用位于中国北方半干旱区的两个观测站(陕西榆林站和内蒙古通辽站)的碳通量及气象数据,获得荒漠灌丛生态系统碳通量的季节动态特征,并定量估算环境因子的极端状况对该生态系统各碳通量的影响。结果表明:(1)榆林站2011—2012年和通辽站2015年的净碳交换量(NEE)分别为-132.8 gC/m^2/yr和-59.6 gC/m^2/yr,表明榆林站碳汇功能更明显;(2)极端水分状况对NEE的影响大于极端温度状况的影响。以生长季平均而言(4—10月),水分和温度的极端状况对榆林站(和通辽站)的NEE的影响最大值分别为0.51 gC/m^2/s(0.26 gC/m^2/s)和0.17 gC/m^2/s(0.20 gC/m^2/s);(3)生长旺盛期(6—8月),高温(榆林站>27℃;通辽站>29℃)状况会抑制植被的光合作用能力,导致榆林站和通辽站的总初级生产量(GPP)相较于正常温度状况分别减少0.37 gC/m^2/s和0.53 gC/m^2/s。