仿生定向液体输送的功能材料表面设计与应用

无外界能量输入及设备辅助的情况下,在基底表面上控制液体自发输送在微流控和流体低能耗运输中具有重要意义。然而,液体的自发输送会被接触角滞后效应及摩擦阻力所阻碍。自然界中的生物(如蝴蝶翅膀、仙人掌、猪笼草、蜘蛛丝和沙漠甲虫)特殊的表面形貌结构能够将收集到的水分自发输送。受此启发,通过表面调控等方法人工合成材料的仿生表界面也可以自发运输液体。近十余年,仿生表面的液体定向输送得到了广泛关注和深入研究,预期在定向集水、宏观液体输送、油水分离、微流控系统等领域具有广泛的应用前景。本综述系统地介绍了定向运输液体功能材料的原理、合成方法及其应用,深入解析了制约其应用的主要因素,并总结和展望了定向运输液体的功能材料在未来发展中所面对的机遇与挑战。     

古尔班通古特沙漠生物土壤结皮反射光谱特征分析

通过对野外采样取得的新疆古尔班通古特沙漠中的生物土壤结皮、裸沙和干枯植被进行反射光谱测定,揭示出在干燥条件下各类地物的反射光谱特征。进一步对经过均匀喷洒0.5和1.0 mm水后的生物土壤结皮分别进行反射光谱测定,并对比分析了原始的和经水化实验后的生物土壤结皮光谱特征。依据生物土壤结皮的光谱特征,提出利用连续统去除技术估算生物土壤结皮覆盖度的方法,结果表明连续统去除光谱的负对数与生物土壤结皮盖度有很好的相关关系(r2=0.990 7)。     

δ13C and δD Values of Opuntia Atacamensis Depending on Different Environmental Conditions in the Atacama Desert of Northern Chile

Abstract

We analysed ¹³carbon and deuterium discrimination in Opuntia atacamensis Phil, at three different sites in the Atacama desert in Northern Chile: At the western Andean slopes, influenced by summer rainfall, in the very arid Chilean central valley, and at coastal fog mountains.

At the most arid site, the central valley, discrimination of ¹³C and D was less (δ-values less negative) and also discrimination more against deuterium. This is an aridity, not an altitude effect.

The differences in ¹³C content may be due to some carbon fixation via the C3 photosynthetic pathway at the more humid sites. Deuterium enrichment at the arid sites might be due to greater discrimination of HDO against H₂O during transpirational water loss.     

新疆古尔班通古特沙漠南缘土壤生物结皮中地衣植物物种组成和分布

本文对新疆古尔班通古特沙漠南缘土壤生物结皮中地衣植物种类及分布特征进行了初步研究.结果表明,该地区参与土壤生物结皮的有13种地衣植物,即藓生双缘衣、拟橙衣、丽石黄衣、准葛尔橙衣、磷网衣、胶衣珊瑚变种、坚韧胶衣、金黄茶渍、碎茶渍、鳞饼衣、网衣、糙伏毛微孢衣、鳞核衣,分别属于5个目,10科.并分析了其分布特征,发现地衣植物的分布与苔藓植物有负相关关系,地衣的分布受到环境温度、太阳辐射强度、降水量等因素的影响.同时我们计算了三个组间的地衣多样性和相似性,发现组1的多样性最高,次为组3,组2的多样性最低.     

Thermal characterization of lacustrine dolomites from the Sambhar Lake playa,Thar desert,India

The Sambhar Lake playa sediments in Thar desert, western India, host a variety of evaporite minerals. Carbonates form a major proportion of the evaporites in a 23 m deep core and several dolomite-rich horizons are recorded. Our XRD and DTA based investigations show that these dolomites are non-stoichiometric and disordered (proto-dolomites) except at one level (4.08 m) from where a well-ordered dolomite is reported. We also record frequent variation in the characteristics of dolomites with depth in terms of structural ordering, Ca/Mg ratio and Fe content. Dolomites reported form the Sambhar Lake playa are interpreted to be authigenic due to the absence of any carbonate rock in the catchment and seem to be derived from a precursor calcite under (sub-) evaporitic conditions. This revised version was published online in July 2006 with corrections to the Cover Date.     

荒漠植物中总脱氧核糖核酸分子的提取方法

建立了荒漠植物总脱氧核糖核酸分子（DNA）的提取方法.荒漠植物叶片加少量交联聚乙烯吡咯烷酮（PVPP粉末）研磨三次以上，得到样品超细粉末.样品粉末迅速加入前处理缓冲液，混匀后低速离心，弃上清留下沉淀物，在沉淀物中加入等体积预热的提取裂解液，混匀后60~70℃温浴1 h.高速离心提取上清液加入纯化液混匀、抽提、离心.再次提取混合液上清，加入预冷的异丙醇，-18℃沉淀DNA 0.5 h以上，异丙醇溶液高速离心，取沉淀用75%乙醇清洗两遍，晾干，加入超纯水溶解.方法具有操作简单和耗时少等优点，操作过程大约2~3 h.DNA损失少，产量高于500 ng/μL.方法提取主要荒漠植物叶片DNA纯度高、完整性好，具有广泛适用性.     

新型空气取水复合吸附剂在沙漠气候下的吸附性能实验研究

提出了一种由粗孔球形硅胶和氯化钙组成的新型复合吸附剂SiO2穢H2O穣CaCl2。介绍了这种吸附剂的配制方法,分析了它吸附湿空气中水蒸气的原理。模拟我国塔克拉玛干沙漠地区高温干燥的气候特点:在空气温度恒为35℃、相对湿度为30%的条件下,对不同CaCl2含量的复合吸附剂和粗孔球形硅胶、细孔球形硅胶、分子筛13X进行了吸附解吸对比实验。实验表明,这种复合吸附剂的平衡吸附量we最大可达0.263kg H2O/kg干吸附剂,是粗孔球形硅胶的5.6倍、细孔球形硅胶的3.4倍、分子筛13X的1.17倍。通过对比分析它们的吸附解吸速度曲线表明,这种复合吸附剂的吸附量大、吸附速度快、解吸速度快。这种复合吸附剂在解吸温度80℃,可解吸97%以上的吸附量。因此,可用太阳能加热解吸,是一种理想的取水用吸附剂。     

荒漠-绿洲交错地带典型植被光谱特征研究

植被对区域生态环境保护具有重要意义,尤其是在荒漠-绿洲交错地带,植被对土壤保持、提高土地的抗剪切性能有重要意义,对土壤风蚀和荒漠化防治的影响作用较大,利用高光谱技术测定并分析荒漠-绿洲交错带典型植被的光谱特性,不仅能够指导区域的植被遥感分类,还能够对植被实行远程监控提供依据。研究借助美国Field Spec 4高分辨率地物光谱仪,在研究区采集棉花、柽柳、梭梭和盐穗木等四种典型植被不同条件下的光谱数据,在对数据进行归类、筛选及综合处理后,分别对原始数据进行FDR(一阶导数反射率)和RLR(倒数取对数反射率)变换。利用原始数据、FDR和RLR分别分析不同植物的光谱敏感波段和表达方式。结果表明：植物的光谱曲线具有类似的变化特征,植被种类不同在“红边”区和近红外780～1 260 nm波段的表达方式区别较大;植物对可见光的吸收非常强烈,对不同波长的光吸收强弱变化会形成波峰和波谷;植物红边特征具有特殊性,蕴含植物自身的特有信息,三种方式的处理结果显示,光谱特征在经FDR计算后,植物光谱红边特征区差异性非常明显;利用三种不同方式处理后的光谱数据,分别来计算改进的植物NDVI值,经RLR变换后重新计算得到的NDVI值在植物不同种之间表现出较大差别,用于植物种类区分的效果明显。     

Polyketides with different post-modifications from desert endophytic fungus Paraphoma sp.

Three new polyketides 4,6,8-trihydroxy-5-methyl-3,4-dihydronaphthalen-1(2H)-one (1), 5,7-dihydroxy-3-(1-hydroxyethyl)-3,4-dimethylisobenzofuran-1(3H)-one (2) and 1-(4-hydroxy-6-methoxy-1,7-dimethyl-3-oxo-1,3-dihydroisobenzofuran-1-yl) ethyl acetate (3) together with seven known analogues (4–10) were isolated from desert endophytic fungus Paraphoma sp. The structures of these compounds were elucidated by analysis of NMR data. The absolute configuration of (1–3) was established on the basis of CD experiments. The possible biosynthetic pathway of compounds (1–10) was suggested, which implied that these secondary metabolites might be originated from polyketide biosynthesis with different post-modification reactions. Compounds 2, and 5–8 were evaluated for bioactivities against plant pathogen A. solani, whereas none of them displayed any biological effects. In addition, compounds 1, 2 and 5–10 were also tested for cytotoxic activities against three human cancer cell lines (HepG2 cells, MCF-7 cells and Hela cells) without biological effects.     

Microstructural analysis of the cementation process during soiling on glass surfaces in arid and semi‐arid climates

To investigate the soiling behavior of solar energy systems like photovoltaics or concentrated solar power, glass samples were exposed to outdoor conditions in Doha, Qatar for one month. Soil formation on the glass was characterized at microstructural level using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Further, elemental analysis of the crust was done with energy‐dispersive X‐ray spectroscopy (EDX). Small fibrous structures were found on the glass surface and dust particles, providing evidence of a cementation process leading to a strong adhesion of airborne dust particles. In contrast to the common perception, that cementation occurs via the precipitation of salt (sodium chloride) these needle structures were found to be mainly composed of oxides of Si, Mg and Al. This indicates that cementation processes in desert regions are enhanced by the growth of fibrous clay minerals.

Cross section of cemented dust particle, connected via small needles to the glass surface.