云南热带山地三种阔叶人工林群落林下植物生活型谱比较

通过样地法比较了高阿丁枫、马尖相思、马尖相思 + 西南桦三种人工林群落林下植物的生活型谱。结果发现,三种类型都以高位芽植物为主,其次为地面芽植物;在高位芽植物中又都以小高位芽植物比例较高;其叶型谱以中型叶为主。生活型谱和叶型谱都与热带南亚热带的群落相似。

山桂花人工纯林与混交林群落学特征比较

通过样地法比较了山桂花的山地人工纯林及山桂花+西南桦混交林群落的生活型谱、叶型谱、植物种类的重要值以及物种多样性等特征,结果发现:山桂花纯林和山桂花混交林都以高位芽植物为主,其次为地面芽植物;在高位芽植物中又都以小高位芽植物的比例为高;山桂花纯林的中、矮高位芽植物比例比混交林高,而混交林的大高位芽植物、藤本高位芽植物比例比纯林高 山桂花纯林和混交林的叶级都以中型叶为主,大型叶次之,2种森林类型各叶级的比例分配基本一致,但两者叶级谱还是略有差异,2种林型的生活型特征符合热带植被的群落学特征 山桂花纯林的物种丰富度要比山桂花+西南桦混交林高,山桂花纯林和山桂花+西南桦混交林的Shannon Wiener指数(H′)值相差不大,而混交林的均匀度要比纯林高 根据群落中各植物重要值的大小,纯林的物种组成主要有:山桂花、鸡血树、黄毛榕、棕叶芦、山菅兰、竹叶草等;混交林的植物种有:山桂花、西南桦、苦竹、短刺栲、西南凤尾蕨、山菅兰、棕叶芦等 纯林和混交林群落层次都分为3层,其中纯林的乔木层树种单一,灌木和幼树层种类较多,多达71个植物种,占总种数的51 82%;而混交林的灌木和幼树层有44种,占总种数的32 12%

四川瓦屋山原生和次生常绿阔叶林的群落学特征

利用野外调查资料 ,比较分析了瓦屋山中山段 (halt15 0 0～ 190 0m)自然恢复的次生和原生常绿阔叶林的群落外貌、群落主要乔木物种组成、高度和径阶结构等特征 .结果表明 :( 1)恢复 42a的次生常绿阔叶林已基本形成中亚热带湿性常绿阔叶的生活型外貌和以中小型单叶为主、草质叶明显的特征 .但与原生的中亚热带湿性常绿阔叶林相比 ,落叶的中小矮高位芽植物明显较多、地面芽和地下芽植物偏少 ;( 2 )次生常绿阔叶林乔木层树种有 6 7种 ,而原生林仅 5 7种 .次生和原生常绿阔叶林乔木层主要优势物种组成相似 ,但次生林优势种更明显 ,并存在较多的处于伴生状态(局部地段还居于优势地位 )的落叶乔木种类 ;( 3)次生林较相同面积上的原生林乔木层的平均胸径DBH<2 .9cm .次生林具有小径阶个体多、大径阶个体少的明显特点 .但两类森林乔木大小结构分布与其它地区的异龄林基本一致 ,均遵从指数分布关系 ;( 4 )次生林 6 40 0m2 内h≥ 3m的乔木有 1199株 .垂直高度h分化不明显 ,hmax=2 2 .8m ,hav仅 9.7m ,而原生林 6 40 0m2 内h≥ 3m的乔木有 10 45株 ,平均高度 12 .8m .次生林缺失VII高度级 ( >2 5m) ,而VI高度级仅 8株 (原生林有 5 5株 ) ,低高度级 (II～IV级 )株数的比例大 ,占总株数的 87.12 % .说明次生林乔木拥?

西南桦人工林与次生林群落学特征比较

通过样地法比较了西南桦人工林与西南桦次生林群落的生活型谱、叶型谱、植物种类的重要值以及物种多样性等特征,结果表明,西南桦人工林与次生林都以高位芽植物为主,其次为地面芽植物;在高位芽植物中又都以小高位芽植物的比例为高;西南桦人工林和次生林的叶级都以中型叶为主,大型叶次之,但在人工林中出现了巨型叶植物,而在次生林中却没有出现,2种林型的生活型特征符合热带植被的群落学特征。西南桦人工林的物种丰富度要比次生林高,西南桦人工林和次生林的Shannon-Wiener指数(H′)值相差不大,而次生林的均匀度要比人工林高。根据群落中各植物重要值的大小,人工林物种组成主要有西南桦、披针叶楠、短刺栲、滇姜花、山菅兰、红果莎、西南凤尾蕨、大叶仙茅、棕叶芦、窄序崖豆藤;次生林物种组成主要有西南桦、中平树、黄牛木、水锦树、棕叶芦、大芒萁、紫茎泽兰、金刚藤、悬钩子、酸藤子等。人工林和次生林群落层次都分为3层,其中人工林的乔木层树种单一,灌木及幼树层种类较多,达62种,占总种数的56.36%;而次生林的灌木和幼树层有28种,占总种数的50.91%。

Preliminary Study on Spectra Diagnosis Model for Nitrogen Nutrition in Rice Leaf

[Objective] The aim was to build spectral diagnosis model for nitrogen nutrition in rice leaf.[Method] Through determination of transmission,absorption spectra and nitrogen content on rice leaves of different rice varieties（Xiangyou 109 and Shanyou 98）,different growth periods and different nitrogen levels,we analyzed the correlation between leaf spectra and their nitrogen contents,and built prediction model of spectral index for nitrogen content in rice leaf.[Result] The detection precision of this model was above 80% that can be used on diagnosing of rice nitrogen nutrition.[Conclusion] The study provided evidence for monitoring nitrogen nutrition status of rice.

An overview of the thermography-based experimental studies on roadway excavation in stratified rock masses at CUMTB

This paper presents an overview of experimental investigations conducted at China University of Mining and Technology Beijing(CUMTB) on roadway excavation using large-scale geomechanical model tests.The simulated sedimentary rocks are composed by alternating layers of sandstone, mudstone and coal seam inclined at varied angles with respect to the horizontal including 0°, 45°, 60°, and 90°. During the excavation, infrared thermography was employed to detect the thermal response of the surrounding rocks under excavation. The obtained raw thermograms were processed using denoising algorithm, data reduction procedure and Fourier analysis. The infrared temperature(IRT) characterizes the overall rock response; the processed thermal images represent the structural behavior, and the Fourier spectrum describes damage development in the frequency domain. Deeper understanding was achieved by the comparative analyses of excavation in differently inclined rock masses using the image features of IRTs, thermal images and Fourier spectra.

Rapid biosorption and reduction removal of Cr(Ⅵ) from aqueous solution by dried seaweeds

Four types of common seaweeds(Laminaria japonica,Undaria pinnatifida,Porphyra haitanensis,and Gracilaria lemaneiformis) were examined to remove Cr(Ⅵ) ions from aqueous solution.The experimental parameters that affected the biosorption process including pH,biomass dosage,contact time and temperature were investigated via batch experiments.The surface characteristics of seaweeds before and after Cr(Ⅵ) adsorption were studied with scanning electron microscopy and Fourier transform infrared spectroscopy.The results show that an initial solution with the pH of 1.0 is most favorable for Cr(Ⅵ) adsorption.Rapid adsorption is observed in the initial stage and adsorption equilibrium state is reached within 1 h.The adsorption efficiency by Porphyra haitanensis is the maximum among four types of seaweed powders,followed by Laminaria japonica and Undaria pinnatifida with biosorption efficiency up to 90%.The removal rate of Gracilaria lemaneiformis is less than 60%.The kinetic data obtained using the seaweeds are found to follow pseudo-second order kinetic model.Experimental sorption data adequately correlate with the Langmuir model.FTIR indicates that amino and carboxyl groups play an important role in the process of Cr(Ⅵ) adsorption and a large percentage of Cr(Ⅵ) ions are reduced by reductive groups on the surface of seaweeds.

Preparation and Characterization of Tungsten-substituted Molybdophosphoric Acids and Catalytic Cyclodehydration of 1,4-Butanediol to Tetrahydrofuran

A series of tungsten-substituted molybdophosphoric acids(H3PMo12-nWnO40·xH2O) were synthesized and characterized by inductive coupled plasma atomic emission spectroscopy(ICPAES),thermal gravimetry and differential scanning calorimetry(TG-DSC),Fourier transform infrared spectroscopy(FTIR),X-ray diffraction(XRD),and FTIR pyridine adsorption.The as-prepared heteropoly acids have a Keggin type structure.The synthesis of tetrahydrofuran by reactive distillation and cyclodehydration of 1,4-butanediol was studied using the tungsten-substituted molybdophosphoric acids as catalysts.The results of catalytic test indicated that the catalytic activity increased with the increase in the substitution number(n) of tungsten atom in H3PMo12-nWnO40·xH2O and was constant as the substitution number(n) was more than 8.The catalytic activity increased with the increase in the catalyst loading and the selectivity of tetrahydrofuran was nearly 100%.

New Environmental Friendly Yellow Ceramic Pigments of the Type （Fe^ⅢM^Ⅴ）-TiO2

The family of Cr（Ⅲ） and Fe（Ⅲ）-doped rutile pigments of nominal composition （M^ⅢM^V）xTi1-2xO2, with M^Ⅲ = Cr（Ⅲ） or Fe（Ⅲ） and M＇（V） = Sb, Nb, Ta, with x = 0.03, 0.15 and 0.25 were investigated as ceramic pigments covering the yellow-ochre-brown palette. The formulations containing Fe（Ⅲ） are novel compositions not included in the commercial rutile pigments. The materials were characterized by XRD （X-ray diffraction） analysis and FTIR （Fourier transformed infrared spectroscopy）. The transition temperature from anatase-to-rutile was estimated by the evolution of the spectral patterns. This crystal phase transition is responsible of the color formation. A higher distortion of TiO6 octahedra is observed in the case of （FeSb） containing cells which contribute to the enhancement of the light absorption. The coloring performance of all the formulations were evaluated by enameling the mixtures containing 5% pigments and commercial frits representative of single and double firing industrial processes. The chromatic values obtained are in the yellow to brown domain of the chromatic plot, depending on the composition of the pigment-frit batch. In the case of the Fe-glazes, and particularly the combination （FeNb）, the chromatic values are close to the best yellow tinting. This new FeNb-rutile pigment could be a more benign substitute of Cr-yellow pigments. The homogeneity of the enamels was confirmed by SEM （scanning electron microscopy）-EDAX （energy dispersive X-ray analysis） microscopy.

Synthesis of a sulfur-graphene composite as an enhanced metal-free photocatalyst

A novel metal-free photocatalyst--sulfur/graphene （S/GR） composite--has been synthesized using a facile one-pot, two-step hydrothermal method with thiosulfate and graphene oxide （GO） as precursors. A green reductant--L-ascorbic add--was used to transform GO to GR under mild conditions. The photocatalyst powders were characterized by Fourier transform infrared spectroscop, X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and energy dispersive spectroscopy. Experimental tests were conducted on the photocatalytic decomposition of methyl orange （MO） by different catalysts. Compared to pure oL-S, the as-prepared S/GR composite showed much enhanced photocatalytic activity for the degradation of MO under both UV and solar light. The presence of GR also greatly increased the hydrophilicity and adsorption capacity of the catalyst material. The results indicate that the incorporation of GR with a-S results in a synergistic effect for the S-based photocatalysts offering more effective environmental applications.

Estimating biophysical parameters of rice with remote sensing data using support vector machines

Hyperspectral reflectance (350-2500 nm) measurements were made over two experimental rice fields containing two cultivars treated with three levels of nitrogen application.Four different transformations of the reflectance data were analyzed for their capability to predict rice biophysical parameters,comprising leaf area index (LAI;m-2 green leaf area m-2 soil) and green leaf chlorophyll density (GLCD;mg chlorophyll m 2 soil),using stepwise multiple regression (SMR) models and support vector machines (SVMs).Four transformations of the rice canopy data were made,comprising reflectances (R),first-order derivative reflectances (D1),second-order derivative reflectances (D2),and logarithm transformation of reflectances (LOG).The polynomial kernel (POLY) of the SVM using R was the best model to predict rice LAI,with a root mean square error (RMSE) of 1.0496 LAI units.The analysis of variance kernel of SVM using LOG was the best model to predict rice GLCD,with an RMSE of 523.0741 mg m-2.The SVM approach was not only superior to SMR models for predicting the rice biophysical parameters,but also provided a useful exploratory and predictive tool for analyzing different transformations of reflectance data.

Multiple-dimensional micro/nano structural models for hydrophobicity of butterfly wing surfaces and coupling mechanism

The microstructure, wettability and chemical composition of the butterfly wing surfaces were investigated by a scanning electron microscope, a contact angle meter and a Fourier transform infrared spectrometer. The micro/nano structural models for hydrophobicity of the butterfly wing surfaces were established on the basis of the Cassie equation. The hydrophobicity mechanisms were discussed from the perspective of biological coupling. The butterfly wing surfaces are composed of naturally hydrophobic material and possess micro/nano hierarchical structures, including primary structure （micrometric scales）, secondary structure （nano longitudinal ridges and lateral bridges） and tertiary structure （nano stripes）. The wing surfaces exhibit high hydrophobicity （contact angle 138°-157°） and low adhesion （sliding angle 1°-3°）. The micromorphology and self-cleaning performance of the wing surfaces demonstrate remarkable anisotropism. The special complex wettability ascribes to a coupling effect of the material element and the structure element. In microdimension, the smaller the width and the bigger the spacing of the scale, the stronger the hydrophobicity of the wing surfaces. In nano-dimension, the smaller the height and the smaller the width and the bigger the spacing of the longitudinal ridge, the stronger the hydrophobicity of the wing surfaces. This work promotes our understanding of the hydrophobicity mechanism of bio-surfaces and may bring inspiration for biomimetic design and preparation of smart interfacial materials.