局部紧Vilenkin群上加权Herz空间中的向量值极大函数不等式

建立了局部紧Vilenkin群上加权Herz空间上向量值极大函数的Fefferman-Stein型加权不等式.     

Lignin biodegradation by the ascomyceteChrysonilia sitophila

The lignin biodegradation process has an important role in the carbon cycle of the biosphere. The study of this natural process has developed mainly with the use of basidiomycetes in laboratory investigations. This has been a logical approach since most of the microorganisms involved in lignocellulosic degradation belong to this class of fungi. However, other microorganisms such as ascomycetes and also some bacteria, are involved in the lignin decaying process. This work focuses on lignin biodegradation by a microorganism belonging to the ascomycete class,Chrysonilia sitophila. Lignin peroxidase production and characterization, mechanisms of lignin degradation (lignin model compounds and lignin in wood matrix) and biosynthesis of veratryl alcohol are outstanding. Applications of C.sitophila for effluent treatment, wood biodegradation and single-cell protein production are also discussed.     

聚氯乙烯/木纤维复合材料的研究Ⅰ.硬脂酸和ABS改性木纤维对复合材料力学性能的影响

为改善聚氯乙烯（PVC）和木纤维两者的界面亲合性，提高PVC／木纤维复合材料的机械力学性能，分别用硬脂酸和ABS来改性木纤维的表面，研究发现用硬脂酸处理木纤维可提高复合材料的拉伸强度，但对复合材料的冲击强度影响不大．ABS处理木纤维可同时提高复合材料的拉伸强度和冲击强度。本文也研究了改性剂用量和木纤维含量对复合材料力学性能的影响。     

Surface wave propagation in wood: prospective method for the determination of wood off-diagonal terms of stiffness matrix

Overall elastic properties of wood can be studied by ultrasonic methods. Orthotropic symmetry is assumed (nine constants). This article describes two methods developed for the determination of three off-diagonal terms of the stiffness matrix. The first method deals with bulk waves (BAW), and the second with surface wave (SAW) measurements. The BAW method requires repeated off-axis measurements and an optimization criterion for selecting the C_ij-terms. The SAW method gives the value of the C_ij-term corresponding to a specific plane of symmetry, from only one on-axis measurement. The six diagonal terms of the stiffness matrix can be obtained easily from on-axis bulk wave measurements. From the nine terms of the matrix, the compliance terms (S_ij) and corresponding technical terms are calculated. Technical constants determined from ultrasonic measurements are in agreement with those obtained by classical statistical methods. The experiments were performed on beech and spruce. The SAW technique is expected to be of more interest for further investigations of wood mechanical properties.     

Wood identification using pressure DSC data

This work addresses the problem of supervised classification of industrial wood species (seven different types in the present study) through their thermo‐oxidative stability. This is evaluated by pressure differential scanning calorimetry (PDSC) using the ASTM E2009. The maximization of the ratio of correct classification and the reduction of the costs of this activity are intended. This supervised classification problem was carried out using two different proposals: applying novel nonparametric functional data analysis techniques, based on kernel estimation, to the original PDSC curves, and using machine learning classification approaches applied to different multivariate data sets. The multivariate data sets were obtained, on the one hand, by estimating the fractal (Hausdorff) dimension of the PDSC curves by several methods, jointly with selecting the parameters from fitting a nonlinear model to the PDSC curves and, on the other hand, applying principal component analysis or partial linear squares to the thermograms. The results obtained show that the PDSC curves can be used to discriminate wood samples when these innovative and traditional statistical techniques are applied. In the best of the cases, a probability of correct classification that equals to 0.92 was obtained. PDSC represents a new alternative to the use of images, spectra, and other thermal signals as thermogravimetric analysis for classification purposes.Copyright © 2013 John Wiley & Sons, Ltd.     

OTR渡越辐射束流测量中的CCD相机系统设计

本文针对OTR束流测量中用到的CCD相机系统,介绍了OTR束流测量的基本原理以及利用专用CCD芯片ICX208CL和AD9929在束测系统中关键部分相机系统设计中的应用,并对ICX208CL和AD9929进行了较为详细的介绍。     

The interfacial adhesion of wood fiber–reinforced UHMWPE composite filled with acid‐treated clay

Wood fiber–reinforced ultrahigh molecular weight polyethylene (wood fiber/UHMWPE) composites have been filled with acid‐treated clay to enhance the adhesion. According to the modification, the interlaminar shear strength of composites has been greatly improved. X‐ray photoelectron spectroscopy and scanning electron microscopy are used to examine the microscopic properties of resultant composites. The enhanced interlaminar shear strength is attributed to the clay interlock, which improves the wetting between wood fibers and resins.     

Pretreatment Characteristics of Waste Oak Wood by Ammonia Percolation

A log of waste oak wood collected from a Korean mushroom farm has been tested for ammonia percolation pretreatment. The waste log has different physical characteristics from that of virgin oak wood. The density of the waste wood was 30% lower than that of virgin oak wood. However, there is little difference in the chemical compositions between the woods. Due to the difference in physical characteristics, the optimal pretreatment conditions were also quite different. While for waste oak the optimum temperature was determined to be 130°C, for virgin oak wood the optimum pretreatment was only achieved at 170°C. Presoaking for 12 h with ammonia solution before pretreatment was helpful to increase the delignification efficiency. Presented at the 29th Symposium on Biotechnology for Fuels and Chemicals     

Analysis of lignin from archaeological waterlogged wood by direct exposure mass spectrometry (DE-MS) and PCA evaluation of mass spectral data

The chemical characterisation of waterlogged archaeological wood is of fundamental importance to understand the degradation processes undergone by wooden objects and consequently to develop suitable consolidation and conservation procedures. Lignin extracted from archaeological waterlogged wood samples was characterized using direct exposure electron ionisation mass spectrometry (DE-MS). DE-MS achieves a mass spectral fingerprint of the sample in a few minutes, avoiding any chemical pre-treatment and requiring only few micrograms of material.Mass spectral data were put in relation to the chemical composition of lignin and evaluated by means of principal component analysis (PCA). The preliminary results, presented in this study, demonstrate the feasibility and the potential of DE-MS as a reproducible and rapid screening method for archaeological waterlogged wood samples.     

MODELING THE EFFECTS OF WOOD AND NON‐WOOD BASED INDUSTRIES ON FORESTRY RESOURCES

Pollution due to the wood and non‐wood based industries is one of the main reasons for the depletion of forestry resources. On the onset of industrial era, the number of industries was less but now it has increased much due to rapid pace of development. Industrialization affects forestry resources in two ways: (i) using raw materials by wood based industries and cut down by non‐wood based industries and (ii) emitting pollutants by wood and non‐wood based industries. In view of this, in this paper, we have proposed and analyzed a mathematical model to assess the effects of wood and non‐wood based industries on the depletion of forestry resources. In the modeling process, it is assumed that wood and non‐wood based industries deplete the forestry resources directly, whereas pollutants emitted by both types of industries decrease the growth rate of forestry resources indirectly. The equilibria are obtained and their stability is discussed. The model analysis reveals that forestry resources decrease due to the growth in wood based industries but the overgrowth in non‐wood based industries and pollutants emitted by them in the environment adversely affect the forestry resources. Numerical simulation is provided to support analytical findings.