最新色差公式:CIEDE2000

分析了印刷行业常用的颜色空间CIELAB的不足，然后详细介绍了CIEDE2000色差公式．最后给出了使用CIEDE-2000计算的实例。     

零距拉伸技术及其在木材工业中的应用

零距拉伸是评价微尺度木材纵向力学强度的有效手段之一。本文阐述了零距拉伸的原理和应用,着重介绍了零距拉伸在木材纤维强度评价,物理化学处理对微尺度木材强度的影响,和在古建筑强度评价中的应用前景。     

人工林桉树木材材色处理研究

试验用漂白剂、酸性染料和其它化学药剂,采用单纯漂白、单纯染色、先漂白再染色和化学着色等不同方案对人工林桉树木材进行了材色改良处理研究.结果发现:单纯漂白可获得一定的材色改良效果:硫化物类药剂配方,效果不明显;双氧水类、次氯酸钠类药剂配方,效果明显,可得到很好的漂白效果.单纯染色,比较难获得好的效果.采用先漂白后染色,获得的材色过于鲜艳.草酸类药剂配方,效果明显,可消除材色缺陷;根据不同配方和处理工艺,可获得从浅粉红色到红棕色的色调.用双氧水做活性剂,引入带发色团的化学药剂,材色改良效果明显,通过调整配方药品的浓度和处理工艺可获得从浅黄色到橙黄色的不同色调和较佳的材质.     

人工神经网络技术在木材科学中的应用

主要从缺陷分类、预测建模、ANN改进与应用三个方面阐述了人工神经网络在木材科学与技术专业方面的应用.其中,BP神经网络是应用最为普遍的一种神经网络,通常与分形、小波等信号分析技术结合使用,达到有效处理信息的目的.此外,采用TD、MSM等技术优化神经网络参数,提高网络处理能力是ANN在本专业应用具有创新意义的尝试.ANN在木材科学与技术中的应用将会越来越广泛而深入.     

Exploring the potential of milkweed stalk in wood plastic manufacture

The physical and mechanical properties of milkweed composites based on different loads of milkweed flour and maleic anhydride grafted polypropylene (MAPP) using polypropylene as matrix are investigated in this study. There levels of milkweed fibers (30, 40, and 50 wt.%), one level of mixed milkweed flour (20:20 wt.% fiber:bark), and two levels of MAPP (4 and 6 wt.%) were used to prepare natural fiber-reinforced composites. Physical and mechanical properties including flexural, tension, impact, and thickness swelling were evaluated according to ASTM standards. The result demonstrated that addition of milkweed flour fluctuates mechanical properties of reinforced composite. However, the optimum load of milkweed flour was different in each test. Generally, 40 wt.% mixed flour composite in comparison with 40 wt.% milkweed composite showed lower mechanical results and higher thickness swelling. MAPP as a coupling agent improved physical and mechanical properties of milkweed-filled composites in most properties. The results of this study depicted positive effects of lignocellulose fibers and coupling gent and also negative effect of bark flour as a function of lower cellulose and higher extractive contents on physical and mechanical properties of milkweed-reinforced composites.     

Improving color stabilization in thermally modified wood by pretreatment with aluminum sulfate vacuum impregnation

The poor anti-weathering performance of thermally modified wood often influences the appearance and service life of wood exposed to an outdoor environment. In this study, wood samples exhibiting ultraviolet (UV) resistance were successfully fabricated by joint aluminum sulfate (Al₂(SO₄)₃) impregnation and thermal modification, and the samples were subjected to accelerated weathering reaching 144 h. Time–dependent changes in the surface color of the control samples and treated samples during weathering were evaluated. Chemical and morphological alterations were analyzed by UV spectrophotometry, attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The results showed that incorporating Al₂(SO₄)₃ into the specimens helped prevent both the photooxidative degradation of lignin and the formation of degradation products. The anti-weathering performance of thermally modified wood pretreated by Al₂(SO₄)₃ impregnation improved because the negative effects of ultraviolet light and water on the wood surface were controlled by the high temperature resistance and encapsulation of the hydrolyzed aluminum flocs. The thermal stability also improved in the impregnated–thermally modified samples, as confirmed by the TG results.

     

Analysis of water adsorption by wood using the Guggenheim-Anderson-de Boer equation

The Guggenheim-Anderson-de Boer (GAB) three-parameter sorption equation has been used to interpret the adsorption and desorption isotherms of water vapour measured for 21 important cultural heritage wood species used in the past for panel paintings and woodcarving. The equation is capable of describing the full shape of the isotherms and yields meaningful physical parameters, especially the monolayer capacity from which the water accessible specific surface area can be obtained. It is demonstrated that average sorption isotherms can be derived using the GAB equation for the sorption data available for sets of specimens and that moisture properties of various wood specimens or chemically modified wood can be more easily compared.     

The potential of colour measurement for strength prediction of thermally treated wood

This paper investigates the effects of thermal treatment of birch with respect to colour and strength. Birch wood was treated at 175 °C and 200 °C for 0 h, 1 h, 3 h and 10 h. In bending-strength experiments, treatment was also performed at 185 °C for 2 h. Both static bending strength and impact bending strength were investigated using multivariate statistics (PLS) for correlation to process parameters, density, EMC, position in board, modulus of elasticity (only in static bending), colour and dimensions of samples. In static bending, two PLS models were designed, one based on process parameters and the other based on colour and EMC. From these models it was concluded that colour is not a useful parameter for prediction of strength. In impacted bending, the correlation was too small to give useful results. One test of static bending strength with matched samples was performed, and it showed a strength reduction of 43% when treatment was conducted at 200 °C for 3 h. Measurement of colour homogeneity of the treated boards showed that the colour is not homogeneous.     

大豆油生产加工中色泽控制措施

一些大豆油含特殊杂质和色素,在脱色过程中白土用量过高,成品油氧化稳定性差。为了防控大豆油制取和精炼过程中色泽加深,降低白土用量,可采取不同的措施:预处理过程中调整参数让部分色素固化,浸出过程中采取多级过滤,降低蒸发和汽提温度,改造汽提塔结构以减少加工色素;精炼过程依据小样实验取得毛油品质数据调整操作参数,对部分脱色设备进行改造。生产精炼包装油按酸价(KOH) 0. 05 mg/g,色泽Y5～6/R0. 5～0. 6;散装油酸价(KOH) 0. 07～0. 08 mg/g,色泽Y7/R0. 7。储备大豆油和酸价(KOH) 2～3 mg/g毛油的脱色白土消耗量在原17～24 kg/t的基础上平均降低30%,包装油的货架期也明显延长。     

The potential of partial substitution of the wood fibre in hardboards by reject fibres from the paper recycling industry

This study evaluates the feasibility of incorporating reject fibres from paper recycling into wet process fibreboards as a partial replacement for virgin wood fibres. The rejects were obtained from newspaper and magazine paper recycling in the form of sludges. Three sludges were obtained from the process steps: coarse screening, fine screening, and flotation. Fibre size and inorganic contents of these fibres are presented. Incorporating rejects into a single layer panel has a negative impact on the visual appearance of the panels. Therefore, a method of making multi-layer fibreboards which permits the inclusion of rejects in the core layer was developed. The board performances were assessed according to EN 310, EN 317 and EN 319. The results indicate that the quantity of rejects incorporated into the panels must be limited. The maximum amount of the rejects, which do not significantly affect board performance, is estimated to be 10 %.     

The compatibility of structural adhesives with wood

An evaluation procedure, based on simple test methods, was developed in order to assess the compatibility with wood adherents of some new types of structural adhesives.Zusammenfassung Ein Bewertungsprozess wurde aufgrund einfacher Testmethoden entwickelt, um die Kompatibilität einiger neuer Typen von Klebern für Bauholz einzuschätzen.

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Die Kompatibilität von Klebern für Bauholz

     

Starch-sugar synergy in wood adhesion science: basic studies and particleboard production

Synergic properties between starch and sugar were discovered. 100% crop-based starch and sugar formulations were studied. Classical preliminary tests such as curing temperature and gel time were measured for different starch-sucrose water suspensions. More significant information was deducted with applied tests such as plywood gluing tests and particleboard production. Wood-to-wood bonding properties were analysed applying NaOH and high temperature (180°C) as catalysts for starch gelification. Comparable strength to commercial urea-formaldehyde and polyvinyl acetate adhesives was achieved in plywood tests. Consequently, the knowledge acquired in wood bonding of flat surfaces was applied to particleboard production. These derived particleboards showed that it is possible to obtain a panel with only carbohydrates as gluing agent. Starch-sugar synergy in alkaline environment increases the internal bond (IB) of the natural panels up to 0.25 N/mm². Possible mechanisms of synergy between these saccharides were proposed. Finally, a blended formulation with Mimosa tannin allows for achieving an internal bond of 0.40 N/mm², which is the required value for interior grade particleboards (DIN EN 312). Starch-sugar-tannin adhesives are 100% environmentally-friendly formulations.     

The compatibility of structural adhesives with wood

An evaluation procedure, based on simple test methods, was developed in order to assess the compatibility with wood adherents of some new types of structural adhesives.     

含葡萄糖培养基高温灭菌变色及其防范措施的研究

研究了葡萄糖浓度、pH值、硫酸铵及氨基酸对葡萄糖溶液高温变色的影响，结果表明pH值是葡萄糖溶液高温变色的主要因素；pH值低于5.5，并且避免与含氨离子化合物共同灭菌，可以有效防止色素的产生。     

互补色在服装色彩设计中的应用分析

互补色在纯艺术领域的绘画中已有较多的探讨和应用,而在服装领域还没有比较具有针对性的理论指导。通过互补色在自然色彩中的表现和美学渊源,得出了互补色服装配色是一种天然的、满足人类大脑视觉平衡系统的色彩设计方法,并接着对互补色服装调和方法以及在品牌服装中的应用进行了分析和探讨,为互补色彩在服装设计中更好地被采用提供一定的理论基础。     

Toward the Re-appraisal of the influence of basic wood characteristics on sawblade potential

A mathematical expression covering the cumulative influence of all basic wood parameters on sawblade behaviour has been established. Theoretically analysed and supported by statistical examination of practical mill production data, this empirical formula provides a simple method of assessing the conversion properties of different timber species. It also forms the basis for further analysis of individual wood parameters and their specific effects on the behaviour of tools.