漆树漆汁道的形态学研究(简报)

<正> 漆树(Rhus verniciflua Stokes)的漆汁道是分泌贮存生漆的场所,与割漆技术的改进,生漆的产量和质量关系密切。七十年代以来国内有关单位十分重视漆树的研究,但对漆树树皮内漆汁道的形态结构看法不一。近几年我们做了部分工作,现简要报道如下。研究用树皮主要采自贵州14个农家品种,并参考了国内生漆主产省标本、图片和资料。取用了不同树龄的胸径或主干树皮。鲜皮用FAA同定,石蜡法制片,整块树皮以氢氧化钾或氢氧化钾、甘油、水合氯醛混合透明,再以双氧水、草酸退色,甘油再透明临时封藏供观测摄影。     

漆树透明标本纵观漆汁道

漆树是我国特有的经济林木之一 ,生漆产量居于世界首位。漆汁道是累积、贮藏生漆的内分泌结构 ,由一层分泌细胞和 2～ 3层鞘细胞围成的腔道 ,遍布于漆树的各个器官。制作漆树透明标本 ,可观察到漆树体内完整的漆汁道形态结构、数量和立体分布规律。1　漆树透明标本的制作原理和方法1 1　制作原理生漆在一定条件 (温度 2 0～ 30℃相对湿度 80～ 90℃ )下 ,由于漆酶的作用 ,漆酚发生氧化 ,凝结成棕红色的漆膜 ,漆膜具有坚固性 ,耐酸碱及各种化学溶剂的特性。根据上述原理 ,人工控制温湿度条件 ,使漆汁道内的生漆凝固成漆膜 ,采取相应的技术措…     

漆树漆汁道的超微结构研究

<正> 生漆是一种优良的天然涂料,是漆树代谢过程的次生产物,由漆汁道分泌和贮芷。近年来,国内外对于漆树及其同科植物漆汁道的显微结构方面已有许多研究报道,但对我国盛产生漆的漆树(Rhus verniciflua)漆汁道的超显微结构至今尚未见报道。为此,我们以漆树树皮为材料,对其次生韧皮部中漆汁道的超微结构进行了观察,并进一步探讨生漆的形成与漆汁道细胞超微结构的关系。现将研究结果报道于后。     

漆树树皮内漆汁道堵塞现象的观察

<正> 生漆是优良的天然涂料,它是漆谢(Rhus vernicifua Stokes)代谢过程中的次生产物,由漆树体内的漆汁道分泌和贮存的。关于漆汁道在树皮内的结构、分布、长度和分枝等方面的规律,西北大学胡正海副教授等人已作了全面系统的研究。但是有关漆树树皮内漆汁道堵塞现象的观察研究,至今未见报道。现将我们的观察研究结果报道如后。     

漆树漆汁道形态结构和特征研究(初报)

本文报道了利用透明和蜗牛酶提取液分离法研究漆树(Rhus verniciflua Stokes)树皮中漆汁道的形态结构和特征,提出了两种排列不同的分泌细胞;描述了盲管网状联接、多次分枝和并联等不同形态特征的漆汁道。     

漆汁道名释与命名

<正> 漆汁道是贮藏、累积生漆的分泌结构。属于裂生形成的分泌道(Secretory Canal)。横切面上观察由1～2层分泌细胞(Secretory Cell)和2～3层小型薄壁细胞组成的鞘围成的道(Canal)或腔(Cavity);弦切面上稀见分枝。分枝状况及道的长短不一,大多数是沿着茎的长轴方向近乎平行伸展的。近年来生漆生产的发展促进了生漆科学研究领域不断扩大,成果不断增加。但是也     

漆树与两种野漆树之间过氧化物酶同工酶及其活性的比较研究

<正> 漆树(R.verniciflua)早在多年前就用于生产生漆,是我国分布最广的经济林树种之一。野漆(R.succedaneum)和木蜡树(R.sylvestre)(在福建分别俗称“福清漆”和“黄毛漆”)的树液中虽然都含有漆汁,但产漆量低且漆质差,都处于野生状态。     

生漆开潮的鉴别及处理

<正> 生漆开潮,也称开潮生漆。主要是生漆中水分超标。漆酚含量低,干燥性差,涂膜硬度减弱,影响了生漆的特性。开潮生漆一般是漆农在采割进程中遇上了降雨,雨水从漆茧直接渗入漆汁中。其次还有些人为的因素造成人为的开潮。一、开潮生漆的感观鉴别生漆开潮后的鉴别,主要从漆质的色、香、味来鉴定,开潮的生漆,漆膜的表面有较多的块状黄迹,皱纹较大不成蜂房状,膜色黄嫩;味淡无酸香,转艳较块,但火红不黑;漆液呆板活力差,丝头无回缩力,不成钩状。开潮生漆除上述感观鉴别外,还可采取与正品漆对比     

生漆中三烯漆酚的加氢反应动力学分析法

<正> 生漆中的主要成份漆酚,是由饱和漆酚、单烯漆酚、双烯漆酚和三烯漆酚组成的混合物。生漆氧化聚合成膜过程同三烯漆酚有密切关系。因此,测定生漆中三烯漆酚的含量是很必要的。由于生漆在空气中易氧化,故在测定漆酚时,一般先将生漆进行化学处理。如用醚化或酯化的方法把苯环上的羟基保护起来,使其成为较稳定的化合物。然后,再进行柱层析分离或气相色谱法、质谱法测定。在化学处理过程中,操作繁杂、费时,特别是在醚化时样品损失较多,不能定量醚化,使色谱法测定     

中国的高级天然树脂——生漆

生漆又名大漆、国漆等。生漆和白油(未加催干剂的熟桐油 )可制成金漆 (也叫广漆或明漆 ,温州地区习惯叫金漆 ,因为它能漆成透明鲜艳的金黄色而得名 ) ,再加松香可制成明光漆 ,还有用生漆制成推光漆 ,以及其它由生漆精制和改性的品种。我国各地城乡人民群众 ,一贯很喜欢采用生漆     

漆树花器官中漆汁道的分布和发育

本文报道了漆树花器官中漆汁道的发生和发育方式。研究结果表明,萼片、花瓣和子房中漆汁道是以裂生方式产生的。但发育到一定阶段,漆汁道腔周围的分泌细胞有与漆汁道中分泌物相似的染色反应。随后,这些细胞脱入腔道,逐渐解体。与此同时,暴露在腔道周围的薄壁细胞逐渐变成分泌细胞。因此,在漆树花器官(雄蕊除外)中,漆汁道的发育是裂溶生的。     

Densification Mechanisms in Hot–Pressing of Magnesia with a Fugitive Liquid

Densification of MgO with LiF additions depends on the formation of a liquid that is initially a lubricant for rearrangement of particles and later a material transport medium for pressure–enhanced liquid–phase sintering. The rate–controlling process in the latter stage is viscous flow of the liquid through grain–boundary channels. After the liquid is distributed as a uniformly thin film between the MgO grains, it can be removed by evaporation, and transparent polycrystalline specimens are produced.     

银盐法制备透明导电膜的研究与应用

本文研究了银盐法制备透明导电膜的方法。该方法是通过对特制的银盐感光胶片进行曝光和显影加工,在聚酯片基上形成由金属银构成的网格图案,再经化学镀处理,制得透明导电膜。该透明导电膜的透光率可达80%,根据不同用途,其表面电阻在0.1~1000Ω/□宽广范围内可调控。该方法可用于制造PDP电视的透明电磁波屏蔽(EMI)膜;也可用于制造触摸屏的导电膜、聚合物和染料敏化太阳能电池的阳极,以替代ITO膜。此外,该方法还可延伸到制作RFID电子标签超高频天线等,具有广泛的应用前景。     

Super-aligned carbon nanotube films as aligning layers and transparent electrodes for liquid crystal displays

Super-aligned carbon nanotube (CNT) film is a transparent conductive film composed of numerous parallel CNTs connected to each other by the van der Waals force. We have found that such films, attached to glass, can readily align liquid crystal molecules. A prototype liquid crystal display (LCD) using the film as the aligning layer has been fabricated. The on-off ratio of the as-prepared display cell is 85 when 24 V is the applied voltage. Because of its high transparency, the film can simultaneously be used as a transparent electrode material, in place of expensive indium tin oxide. The resistance of the film makes it a suitable built-in heating layer, extending the working temperature range of LCDs.     

Transparent Conducting Electrodes from Conducting Polymer Nanofibers and Their Application as Thin‐Film Heaters

Transparent conducting electrodes attract attention in relation to solar cells, touch panels, displays, e‐readers, and transparent heaters. In many cases, rarefied metal nets with optical transmittance of ≈90% and with minimal sheet resistance are sought after. Here, a mesh of conducting polymer nanofibers is developed as a transparent conducting electrode. A sheet resistance of 8.4 kΩ sq⁻¹ with 84% optical transmittance is achieved with polyethylene oxide/poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEO/PEDOT:PSS) blended polymer nanofibers. This study also demonstrates that such nanofiber being deposited on a glass substrate can be used as a transparent film heater in relevant applications such as window heating or displays at harsh environments. Such a transparent heater is rated at 0.41 W in.⁻² for 120 V. It is also capable of heating a substrate up to ≈70 °C in 4 min at 60 V from room temperature without any degeneration of nanofiber network, rendering itself as a practically useful transparent heater. The performance of the PEO/PEDOT:PSS nanofiber‐coated transparent glass heater is comparable to that of the relatively expensive indium tin oxide thin‐film heaters.     

Quantifying Water at the Organic Film/Hydroxylated Substrate Interface

A method, based on Fourier transform infrared-multiple internal reflection (FTIR-MIR) spectroscopy, for determining the amount and thickness of water at an organic film/hydroxylated substrate interface has been developed. The analysis uses a two-layered model, which takes into account: 1) water at the organic film/hydroxylated substrate interface, 2) water taken up by the organic film within the penetration depth of the evanescent wave and 3) change of the penetration depth as water displaces the organic film from the substrate. Experimentally, the method requires the application of an organic film, transparent or opaque, of sufficient thickness on a hydroxylated internal reflection element, which is used as the substrate. A water chamber is attached to the organic-coated specimen. After adding water to the chamber, FTIR-MIR spectra are taken automatically at specified time intervals without disturbing the specimen or the instrument. Water uptake in the organic films and FTIR-MIR spectra of water on the substrates are also obtained and used for the analysis. Results of examples of three organic films: a clear epoxy, an unmodified asphalt, and a pigmented ester, on a hydroxylated SiO₂-Si substrate were presented to demonstrate the method. The water layer at the interface for the ester and asphalt specimens was found to be much thicker than that for the epoxy, and this was attributed to the presence of a water-sensitive layer accumulated at the interface for the formers. The method should be equally applicable to studies of organic and inorganic compounds at the organic film/hydroxylated substrate interface and their transport rates through films adhered to a substrate.     

An all-graphene based transparent and flexible field emission device

All-graphene based cathode and anode structures were fabricated and their application as a flexible and transparent field emission device is presented. The graphene film was grown on a Cu foil by thermal chemical vapor deposition and later transferred to a polymer substrate through a hot press lamination technique. Multiwall carbon nanotubes (MWCNTs) were spin-coated onto a graphene film on a transparent, flexible substrate to form the cathode of the field emission device. A green-phosphor coated graphene-PET film was used as the anode. The device showed good transparency and flexibility as well as giving an appreciable emission current. The simple processing techniques used can easily be upgraded to a larger scale and be tailored for any transparent and flexible substrate. The device offers exciting applications of carbon nanostructures in foldable electronics.     

Silver nanowire-based transparent,flexible, and conductive thin film

The fabrication of transparent, conductive, and uniform silver nanowire films using the scalable rod-coating technique is described in this study. Properties of the transparent conductive thin films are investigated, as well as the approaches to improve the performance of transparent silver nanowire electrodes. It is found that silver nanowires are oxidized during the coating process. Incubation in hydrogen chloride (HCl) vapor can eliminate oxidized surface, and consequently, reduce largely the resistivity of silver nanowire thin films. After HCl treatment, 175 Ω/sq and approximately 75% transmittance are achieved. The sheet resistivity drops remarkably with the rise of the film thickness or with the decrease of transparency. The thin film electrodes also demonstrated excellent flexible stability, showing < 2% resistance change after over 100 bending cycles.     

Preparation and Photoproperties of a Transparent Alumina Film Doped with Energy-Transfer-Type Laser Dye Pair

Doping of an energy-transfer-type laser dye pair into an alumina film was tried in order to increase the efficiency of its photoproperties. A transparent alumina film was prepared from an aqeous sol solution by the sol—gel process. Changes in the fluorescence of the pyranine were monitored during the process from aqueous sol solution to the dried gel. The undesirable dye aggregation usually observed in aqueous solution was largely reduced in the film. The laser emission of rhodamine B by N₂ laser pumping can be increased by the addition of rhodamine 6G, which enhances pumping efficiency. It indicates that this doped film operates as a compact dye laser film.