Characterization of sp<Superscript>2</Superscript>- and sp<Superscript>3</Superscript>-bonded carbon in wood charcoal

Japanese cedar (Cryptomeria japonica) preheated at 700°C was subsequently heated to 1800°C and characterized by electron microscopy, X-ray diffraction, and micro-Raman spectroscopy. The degree of disorder of carbon crystallites and the amount of amorphous phase decreased considerably with an increase in heat treatment temperature to 1400°C, while carbon crystallites clearly developed above this temperature, showing that the microstructure of carbonized wood undergoes drastic changes around 1400°C. Besides showing the bands for sp²-bonded carbon, the Raman spectra showed a shoulder near 1100 cm⁻¹ assigned to sp³-bonded carbon. With an increase of heat treatment temperature, the peak position of the Raman sp³ band shifted to a lower frequency from 1190 to 1120 cm⁻¹, which is due to the transformation of sp³-bonded carbon from an amorphous phase to a nanocrystalline phase. These data showed that the microstructure of carbonized wood from 700° to 1800°C consisted of the combination of sp²- and sp³-bonded carbon, which is probably due to the disordered microstructure of carbonized wood. It is suggested that the sp³-bonded carbon is transformed from an amorphous structure to a nanocrystalline structure with the growth of polyaromatic stacks at temperatures above 1400°C.     

Distribution of (1-3)(1-4)-β-d-glucans in kernels of selected cultivars of naked and hulled barley

The objective of this study was to determine the distribution of (1-3)(1-4)-β-d-glucans in the kernels of three high-glucan lines of naked barley (STH 4561, STH 4671 and STH 4676), a low-glucan line (STH 4572), and two low-glucan comparative cultivars (naked – Rastik, and hulled – Stratus). The content of (1-3)(1-4)-β-d-glucans assayed with the enzymatic method varied within the range from 4.04 to 5.71% dry matter basis. Microspectrophotometric analysis revealed significant differentiation in the structure of the kernels and in the distribution of (1-3)(1-4)-β-d-glucans; it also indicated a necessity of applying such processing methods as are appropriate to the distribution of functional components. The distribution of functional components in the high-glucan lines of naked barley makes them ideal for utilization both in the milling technology and in the production of grits and flakes.     

刺五加不同叶位叶片光合特性及显微结构研究

研究了全光照和遮阳条件下刺五加5年生树不同叶位叶片光合特性及显微结构。结果表明,全光处理上部叶（1-3片）和下部叶（8～10片）的光饱和点均高于遮阳处理上部叶（1-3片）和下部叶（8～10片）,而光补偿点却均低于遮阳处理。不同处理和不同叶位叶片显微结构也存在区别,遮阳处理叶片厚度低于全光处理,上部叶的栅,海比高于下部叶的栅／海比。说明叶片结构的改变可能是光诱导的结果,并引起了光合特性的不同。     

Microscopy techniques and image analysis for evaluation of some chemical and physical properties and morphological features for seeds of the castor oil plant (Ricinus communis)

Ricinus communis seed is a source of protein and oil with a high potential to use as animal's feedstock and biodiesel production. However, the oil yield and the extraction efficiency depend on the process conditions applied, as well as on the physical, chemical and structural properties of the seed, which have not been fully investigated. Hence, the objective of this study was to evaluate some chemical and physical properties of R. communis seed as well as to describe and quantify the macro and microstructure of this raw material by microscopy techniques and image analysis. Chemical analysis confirmed the seeds’ high contents of protein (28.48 ± 0.25%) and fat (51 ± 0.31%). On the other hand, the values of geometric mean diameter (8.95 ± 0.05 mm), bulk density (538 ± 11 kg/m³), and true density (1458 ± 27 kg/m³), among others, were higher than the ones reported about similar oils seeds. Microstructural studies showed that the endosperm cells presented an ovoid shape, as obtained from the aspect ratio results (AR = 1.28 ± 0.17), and a cell density of 570 ± 10 cell/mm², resulting in a porous structure, while the embryo cells had a cell density of 4903 ± 2 cell/mm², and an AR of 2.41 ± 0.48, related to a more compact structure (rectangular form) in this part of the seed. Regarding to lipids bodies (lb), they were only visible in the endosperm cells, showing a circular shape (AR = 1.16 ± 0.1), and a mean cell density of 9.57 ± 2.40 lipid bodies/μm², associated to protein as observed by the mineral presence (K, P, Mg and S) as determined by the energy dispersive X-ray analysis. Microscopy techniques and images analysis were efficient tools for the characterization of macro and microstructure of seeds and the data obtained integrate numerical information that could be useful for thermal and mechanical processing of R. communis seed, as well as for the design process equipment.     

北京地区棚栽台湾青枣叶片性状对比研究

以北京地区大棚栽植的台湾青枣9个品种的叶片为材料,分别对其表型进行观察对比,对其叶面积、叶绿素含量等指标进行测定分析,并利用石蜡切片技术对显微性状进行观察对比,研究了不同品种间叶片性状差异。结果表明:北京地区棚栽台湾青枣各个品种间叶片性状表现差异显著,但部分品种内指标间表现并不一致,为北京地区台湾青枣的引种栽培提供了一定依据。     

铬胁迫下李氏禾显微结构的变化

[目的]为研究李氏禾的耐铬生理和分子机理提供理论依据。[方法]以李氏禾幼苗为试材,分剐用含O（对照）、5、30、60mg／LCrCl3的1／2Hoagland营养液进行培养,培养45d后收获,分别测定根、茎、叶的生物量,用石蜡切片法观察不同组织显微结构的变化,用火焰原子吸收法测定各组织的铬浓度。[结果]除5mg／LCrCl3处理外,其他处理根、茎、叶的生物量均随CrCl3浓度的增加而减少,但与对照差异不显著。当CrCl3处理浓度≤30mg／L时,根、茎、叶和总生物量分别减少8．2％、11．6％、21．5％和13．2％;受铬污染的李氏禾根、叶组织结构与对照无明显差异。但茎的维管束明显缩小;转移系数（叶中铬含量与根中铬含量之比）随CrCl3处理浓度的增加而减小（从1．07减小到0．09）。[结论]李氏禾对铬有很强的耐性和积累能力。摘要[目的]为研究李氏禾的耐铬生理和分子机理提供理论依据。[方法]以李氏禾幼苗为试材,分剐用含O（对照）、5、30、60mg／LCrCl,的1／2Hoagland营养液进行培养,培养45d后收获,分别测定根、茎、叶的生物量,用石蜡切片法观察不同组织显微结构的变化,用火焰原子吸收法测定各组织的铬浓度。[结果l除5mg／LCrCl,处理外,其他处理根、茎、叶的生物量均随CrCI,浓度的增加而减少,但与对照差异不显著。当CrCl,处理浓度≤30mg／L时,根、茎、叶和总生物量分别减少8．2％、11．6％、21．5％和13．2％;受铬污染的李氏禾根、叶组织结构与对照无明显差异。但茎的维管束明显缩小;转移系数（叶中铬含量与根中铬含量之比）随C以l,处理浓度的增加而减小（从1．07减小到0．09）。I结论I李氏禾对铬有很强的耐性和积累能力。     

Influence of histories on dynamic viscoelastic properties and dimensions of water-swollen wood

The influences of heating history, cooling method, and cooling set on microstructures and the mechanical properties of water-swollen wood were studied by measuring viscoelastic properties and dimensional changes while elevating temperatures between 20°C and 90°C. Both the viscoelastic properties and dimensional changes of waterswollen wood in the first heating process were quite different from those in the other heating processes. The results revealed that the molecular state of green wood around room temperature was stabilized and could not return to this state if drying or heating was carried out. Cooling methods greatly affected the viscoelastic properties, while they hardly affected dimensional changes when the temperature was elevated. Localized stress in the microstructures of water-swollen wood produced by quenching affected the mechanical properties in the heating process, while external stress less than the proportional limit caused by a cooling set had no effect. This revealed that much greater localized stress linked to the instability of waterswollen wood than the external stress in relation to the cooling set occurred. Part of this report was presented at the 53rd Annual Meeting of the Japan Wood Research Society, Fukuoka, March 2003     

生物柴油/柴油发动机排放颗粒电镜分析

利用高分辨率透射电镜研究了三缸直喷式柴油机在两种供油提前角和两个工况时,燃用两种比例的生物柴油/柴油混合燃料时产生的颗粒微观结构和尺寸。结果表明,在所研究的条件下,发动机燃料燃烧产生的颗粒由球形的原始粒子构成,且呈现出不同形状,具有分形结构特性;原始粒子具有多层类石墨微晶结构,且存在无序内核区。B0和B20燃料产生的原始粒子的直径分别在25.6～31.3 nm和28.7～40.0 nm之间,燃用生物柴油时产生的颗粒原始粒子平均直径大于柴油。     

空间飞行对不同紫花苜蓿品种叶片显微结构的影响

利用神舟3号飞船搭载的4个紫花苜蓿(Medicago sativa L.)品种的种子,返回后对搭载组和对照组植株叶片显微结构进行分析。结果表明:4个品种叶片厚度均显著大于对照,叶脉突起度均显著小于对照(P<0.05);栅栏组织厚度显著大于对照(P<0.05);阿尔冈金的海绵组织厚度显著小于对照,其他品种均显著大于对照(P<0.05);与对照相比,德福的细胞结构紧密度、细胞结构疏松度与对照差异均不显著,阿尔冈金的细胞结构疏松度与对照差异不显著,其他品种细胞结构紧密度、疏松度与对照均有显著差异(P<0.05)。这些变异的产生可能影响其抗性表现,故可作为进一步抗性选育的依据。     

竹炭制备SiC陶瓷材料的形态特征研究

以毛竹、麻竹、绿竹和印度莉竹为原料,先经炭化处理制成竹炭,然后于1450℃高温下采用熔融Si渗透技术制得SiC陶瓷材料。借助SEM对竹炭和SiC陶瓷材料的微观构造、形貌特征进行了分析。结果表明:竹基SiC陶瓷材料继承了竹材的各向异性和微观构造特征;竹基SiC陶瓷是一种包含单质Si、C和SiC多相成分的复合材料;由4种竹材制成的SiC材料在微观构造、形貌特征上表现出一定的差异性。