荷叶表面纳米结构与浸润性的关系

通过烘烤、化学萃取及物理剥除等方法改变荷叶表面的纳米结构和化学组成, 在环境扫描电镜(ESEM)和全反射红外光谱(ATR)对样品的微观形貌和化学组成进行表征的基础上, 为消除其它外界因素影响样品的真实微观形貌, 进一步采用原子力显微镜(AFM)进行了表征. 通过测量不同处理方法所得样品的表观接触角表征了样品的浸润性质. 结果表明, 荷叶表面的蜡质是产生表面疏水性的根本原因, 其微米级结构放大了其疏水性, 而纳米结构是导致其表面高接触角、低滚动角, 即“荷叶效应”的关键原因.     

Superhydrophobic nanostructures based on porous alumina

Superhydrophobic polytetrafluoroethylene (Teflon®, DuPont) sub-micro and nanostructures were fabricated by the dipping method, based on anodization process in oxalic acid. The polymer sticking phenomenon during the replication creates the sub-microstructures on the negative polytetrafluoroethylene nanostructure replica. This process gives a hierarchical structure with nanostructures on sub-microstructures, which looks like the same structures as lotus leaf and enables commercialization. The diameter and the height of the replicated nano pillars were 40 nm and 40 μm respectively. The aspect ratio is approximately 1000. The fabricated surface has a semi-permanent superhydrophobicity, the apparent contact angle of the polytetrafluoroethylene sub-micro and nanostructures is about 160°, and the sliding angle is less than 1°.     

大豆叶片呼吸与植被指数和叶片性状的关系

为研究大豆叶片呼吸与植被指数和叶片性状的关系,设置田间试验,观测不同生长阶段的大豆顶1叶、顶2叶、顶3叶叶片呼吸及呼吸系数,并观测归一化植被指数(NDVI)、差值植被指数(DVI)、比值植被指数(RVI)、增强植被指数(EVI)、光化学植被指数(PRI)、红边叶绿素指数(RECI)6种高光谱植被指数以及叶绿素相对含量(...     

Monitoring of heavy metals in topsoils, atmospheric particles and plant leaves to identify possible contamination sources

The research reveals results of metal pollution on urban topsoil in relation to the metal content in leaves of two plant species and atmospheric particles. The content of pollutants (Ba, Cd, Cu, Fe, Mn, Ni, Pb, V and Ti) was determined by ICP-OES. Twenty-two samples of soil were collected over a six-month period from two different urban sites and one from a rural zone. Regarding the pollution level, the studied soils were found to be low. Results for enrichment (EF) and concentration (CF) factors showed that soils were enriched in Pb, Ba, Cu and Ni. However, both species of plants showed a common behavior for all elements acting as excluders. ANOVA and different multivariate statistical analyses confirmed that the main pollution source of soil was traffic and fertilizers. Cd, Fe, Mn, Ti and V elements were attributed to natural sources. Also, it was suggested that N. oleander leaf is useful as a bio-monitors of soil pollution by Cu. Similarly, a direct relationship was found between the content of Cu in soils with the Cu level in PM₁₀ atmospheric particles. The origin was attributed to dry and wet atmospheric deposition processes.     

21种桉叶微量元素含量测定及其意义

首次报道广东海康金星农场栽培的21种桉叶的微量元素含量和测定方法。结果认为：桉叶中含有Zn、Cu、Fe、Ca、Mn、Mg等人体必需的微量元素，其中Fe和Mn的含0量比其它微量元素高出3～4个热量级，而Fe和Mn是人体需要的微量元素，桉叶是富Fe、Mn的植物资源，它作为中药和动物鰕料添加剂是适合的。     

Investigation of element distributions between the symplasm and apoplasm of cucumber plants by TXRF spectrometry

The lead, iron and manganese distribution between the symplasm and apoplasm of cucumber plant parts (root and leaves) was determined by total reflection X-ray fluorescence spectrometry (TXRF). Plants were grown in control or in lead-contaminated (10⁻⁵M Pb) nutrient solutions containing iron in the chemical form of Fe(III)–EDTA or Fe(III)–citrate. The total concentrations of metals in the dried plant parts were measured after their microwave-assisted digestion. For the determination of the distribution of the elements investigated between the apoplasm and symplasm, the dried root and leaf samples were infiltrated and washed with a solution containing 10 mmol/dm³ Na₂EDTA and 0.5 mmol/dm³ CaSO₄. Elements in the washing solutions and in the washed plant parts were characteristic of the apoplasm and symplasm, respectively. It was established that lead accumulated mainly in the root apoplasm. Going up towards the shoot, in the leaves, there was approximately 50–60% of lead in the symplasm. The iron — similarly to lead — was found mainly in the apoplasm in the root, while in the leaves the symplasm/apoplasm ratio was 55:45%. The distribution of manganese between the symplasm and apoplasm did not show any significant change under the different treatments. In contrast with lead and iron, there was 70% and 60% of manganese in the symplasm of the root and of the leaves, respectively.     

茶树叶与根表面的XPS表征

利用X射线光电子能谱(XPS)研究了茶树叶与根的表面化学组成与结构。结果表明,茶树表面主要由C, O, N和Al等四种元素组成,在茶树叶远轴面还有少量的P和F。通过查阅标准图谱数据库、参照木材表面XPS分析结果,对茶树表面测得的C1s结合能采用曲线拟合与分峰,得到三种形态：结合能为285 eV的是C1,来自C—C或C—H,代表角质、蜡质等脂类化合物;C2的结合能在286.35 eV（近轴面）和286.61 eV（远轴面）,是能够与氧形成单键的C—O,主要源于表面的纤维素;C3的结合能为288.04 eV（近轴面）和288.09 eV（远轴面）,为CO基团标志,综合N（1s）的结合能（399～401 eV）和O（1s）的分峰情况,为蛋白质的酰基标志。茶树根表面除含有与叶表面相同的C1(结合能285 eV)、C2（结合能286.49 eV）和C3（结合能288.78 eV）所代表的角质、蜡质、纤维素和蛋白质之外,还出现了结合能为283.32 eV的C5。由于其结合能低于C1,推测为茶树根表面的有机金属形态。茶树叶和根表面没有木材表面具有的羧基C4,说明根系分泌的有机酸游离存在于根表面。对茶树表面O（1s）图谱的拟合结果与C（1s）结果相吻合。计算不同C和O形态所占的比例得知,茶树叶面远轴面含氧基团多于近轴面,呈较高的氧化状态,因此远轴面化学性质较活泼;与叶相比,茶树根的角质和蜡质含量显著降低,含氧基团相对增多,因此化学性质较活泼,适于水分子和其他溶质分子通过。由于蛋白质含量为根表面＞远轴面＞近轴面,表明根表面的湿润度高于叶表面,而远轴面湿润度高于近轴面。存在于茶树表面Al的结合能均大于单质铝72.7 eV,在73.50 eV以上,为Al₂O₃形态,这将增大茶树表面的吸附作用。由于根表面Al₂O₃含量高于叶面,显示根具有更强的吸附能力。     

Optimization and numerical investigation of an excavator carrier

The excavator carrier is a device for moving the excavator. There are many operational benefits in using this carrier to transport excavators safely, easily, and efficiently. An earlier model of this carrier is manufactured and in tests showed that the design needs to be improved. In this paper, a finite element method is used to model and analyze this carrier and optimize the design for better performance. The static and dynamic analysis is done to optimizing carrier design for removing the defect that identified in practical test. The goal of optimization is to increase the carrier's life, increase the safety of transportation, decrease the cost, and finally, commercialize the product. The results show that the carrier's weight is decreased by up to 30%. Also, a holder and lock system in the back of the carrier is designed for increasing the transportation safety and the stiffness of the carrier chassis. The effect of increasing a suspension system is studied, the idea is using leaf spring. The numerical results show that using the suspension system increases the carrier's life by up to 30% while adding a suspension system increases manufacturing costs by up to 10%.     

离子色谱-直接电导法测定碱土金属和过渡金属离子

本文报道离子色谱-直接电导法测定碱土金属和过渡金属离子。研究了流动相pH值、乙二胺浓度及柠檬酸和酒石酸浓度对金属离子分离的影响。结果表明,以乙二胺-柠檬酸为流动相可以同时分离碱土金属和过渡金属离子。用乙二胺-酒石酸作为流动相可以分离碱土金属离子。方法检出限为0.09~1.88 mg/L,加标回收率为97.6%~98.7%。该方法用于叶面肥试样的分析,结果良好。     

联合MODIS与MISR遥感数据估算叶面积指数

多光谱传感器MODIS与多角度传感器MISR同时搭载在美国EOS观测计划的Terra卫星上,不同的观测方式使得两个传感器的数据组合后形成互补的多光谱多角度观测数据集,为地表参数的遥感估算提供了更多的对地观测信息.该文通过研究组合MODIS与MISR两种观测数据估算陆地表面植被覆盖区域叶面积指数的方法,发展了在物理模型反演的框架内引入基于伴随模型和信赖域优化的反演模式,改进了叶面积指数的遥感估算效果,提高了模型反演的运算速度.对试验区反演结果的验证说明融合两种数据源可以提高叶而积指数的估算精度.基于伴随模型和信赖域优化的地表参数反演方法,为应用于大范围遥感图像数据的模型反演提供了一种有效的途径.