基于近红外光谱技术预测木材纤维长度

介绍了近红外光谱分析技术应用于测量木材纤维长度的基本原理及流程.采用化学计量学中的偏最小二乘和完全交互验证法,通过建立了我国人工林造纸针叶材湿地松和阔叶材滩地72杨木材样品近红外光谱与纤维长度实验值之间的校正模型,来预测相就树种木材的纤维长度.模型的相关指标表明,近红外光谱分析技术可以快速准确地对这两种木材的纤维长度进行预测.     

近红外光谱分析技术的应用研究

简要介绍了近红外光谱的原理、特点,综述了近红外光谱在农业、食品、制药、石油化工、木材工业等领域快速分析上的研究及应用现状,并对近红外光谱的应用前景进行了展望。     

近红外光谱法测定欧美杨纤维形态和结晶度

以北京顺义、山东菏泽及河北廊坊地区不同立地条件的5个品系欧美杨为原料,进行纤维长度和结晶度的分析,采集样品的近红外谱图,结合样品X射线衍射测量值和谱图,运用OPUS软件建立近红外光谱模型,为纤维长度和结晶度的测定提供一个新的方法。对欧美杨纤维长度和结晶度进行了建模,通过预测模型对未参与建模试样进行预测,纤维长度校正模型相关系数为0.969,预测值与X射线衍射测定值的相关系数可以达到0.900。说明该模型相关性很强,可以较准确地预测未知欧美杨样品的纤维结晶度;结晶度校正模型相关系数为0.944,预测值与X射线衍射测定值的相关系数可以达到0.860,该模型相关性较强,通用性较好,能预测未知欧美杨样品的纤维结晶度。     

Silviscan：木材及纤维性能分析测试仪

木材及其纤维的物理化学性能是决定纸的质量及生产成本的重要因素.将木材及纤维的性能与最终产品的生产性能联系起来,可以使木材获得最大程度的应用.但传统的纤维性能检测方法需要花费大量时间,Silviscan可以快速测量很多重要的木材及纤维的性能,对于林业及制浆造纸工业有重要意义.文章主要介绍了silviscan的发展历程及其测量原理,以及在林业及制浆造纸工业中的应用.实际的应用表明,Silviscan是一种快速有效的木材纤维性能测试仪器,与近红外光谱相结合,还可以对大量的样品进行快速、准确的性能预测.     

近红外光谱分析技术在制浆过程中的应用

近红外光谱分析技术是一种高效、无损的快速分析方法,作为实时成分分析和过程控制的先导技术,正逐渐成为制浆过程分析测量领域的研究热点。文中介绍了近红外光谱分析技术的测量原理、技术特点、建模方法等,并对近红外光谱分析技术在制浆过程中的原料分类筛选、材性分析、纸浆性能评估等方面的应用进行了综述。     

近红外光谱技术(NIR)在制浆造纸工业中的应用

介绍了近红外光谱(NIR)的发展历史及其工作原理、技术特点以及应用现状,并着重介绍了其在制浆造纸应用领域,如预测新闻纸厂脱墨浆中胶黏物含量、预测木材冷水、热水、1.0%NaOH和苯醇抽出物含量、纸浆中木素含量的测定方法等,展示了近红外光谱分析技术在制浆造纸领域巨大的应用前景.     

火炬松树龄和材性对纸浆得率及成纸性能的影响

为了用火炬松生产箱纸板浆,探讨了火炬松的树龄和材性与制浆得率及成纸性能的关系。选择树龄为13年和22年、密度及木素含量不同的火炬松,采用化学分析、近红外光谱分析、SilviScan分析等方法对木材纤维特性进行表征。对两种树龄木材进行硫酸盐法制浆并检测其成纸性能。采用多重回归分析确定影响纸张性能的主要木材特性,并推导出纸张性能与树龄、木材相对密度和化学成分之间的相关关系。实验结果表明。树龄13年和22年的木材成浆性能的主要差异是由木材基本特性差异造成的。从木材的近红外光谱分析可预测纸浆的性能,并能预估其成纸的主要性能。     

光谱分辨率的选取对食用油近红外模型性能影响分析

近红外光谱仪的类型和工作参数的设定对测量过程和分析结果均有一定影响.重点讨论了在傅立叶变换型光谱仪上设定不同的光谱分辨率对食用油近红外定量模型性能的影响.实验采用Vertex 70光谱仪,在3种光谱分辨率(4,8,16 cm-1)条件下,采用透射式液体光纤探头采集60份食用油样品近红外谱图.针对3组近红外光谱样品集,分...     

近红外光谱分析技术在蔬菜农药残留检测中的初步探索

本文介绍了近红外光谱分析技术的原理和特点,基于近红外光谱分析技术对蔬菜中农药残留的检测方法进行了实验研究.选取菠菜作为叶菜代表,将其经过化学前处理配制成样品溶液,进行光谱扫描,用偏最小二乘(PLS)建立分析模型.实验表明,预测结果比较理想.     

近红外光谱技术在稻米品质分析中的应用

介绍了近红外光谱分析技术的原理、特点和分析程序,综述了近红外光谱分析技术在稻米品质分析中的应用,对近红外光谱分析技术的应用前景进行了展望.     

近红外光纤光谱法快速检测葡萄酒中酒精度

目的 构建近红外光纤传感检测系统,结合近红外光谱分析技术和化学计量学,对葡萄酒中酒精度进行快速检测.方法 以葡萄酒为研究对象,构建近红外光纤传感检测系统,分别使用偏最小二乘法和主成分回归对葡萄酒中酒精度进行近红外光谱分析,进行模型参数的比较.采用国标GB/T 15038-2006《葡萄酒、果酒通用分析方法》中气相色谱法...     

Investigation of the interrelations between defibration conditions,fiber size and medium-density fiberboard (MDF) properties

Defibration conditions and raw material properties affect wood fiber characteristics, and thereby the properties of fiber-based panels such as high-density fiberboard (HDF), medium-density fiberboard (MDF) and wood fiber insulation board. This study investigates the influence of steaming conditions (time and temperature), grinding disc distance, wood species (pine, beech, birch and poplar), method of refiner discharging (radial and tangential stock outlet) and wood chip size on fiber length and fiber length distribution, and further the influence of fiber size on MDF properties. Fiber lengths were determined applying the recently developed image analysis-based fiber size measuring system FibreCube. This system enables an automated and nearly complete mechanical separation of woolly-felted fiber samples prior to image acquisition, software-supported post-separation of overlapped-lying fibers at the beginning of image analysis, and flow line tracing-based length measurement. It was found that grinding disc distance and wood species are the most influential parameters on fiber length characteristics. Especially the content of undefibrated fiber bundles (shives) was found to strongly correlate with the grinding disc distance. Wood anatomical differences between hardwood and softwood were reflected clearly by the fiber length characteristics. Fiber size was found to be one of the parameters influencing panel properties. However, other fiber characteristics—in particular the chemical nature of the fiber, which is responsible for its wettability with water (thickness swelling) and glue (mechanical properties)—have to be considered as important influencing parameters on panel properties.     

Discrimination of “Louros” wood from the Brazilian Amazon by near-infrared spectroscopy and machine learning techniques

European Journal of Wood and Wood Products - The integration of near infrared spectroscopy (NIR) with machine learning techniques can be an adequate method for discrimination of wood...     

近红外光谱法快速测定木材纤维素、戊聚糖和木质素含量的研究

探讨了近红外光谱法快速测定木材纤维素、戊聚糖和Klason木质素含量的可行性。用常规实验室方法测定106种木材样品的纤维素、戊聚糖和Klason木质素含量,用近红外光谱仪采集相应样品的光谱。利用偏最小二乘法（PLS）和完全交叉验证方式,对原始光谱进行一阶导数＋矢量归一化（SNV）和一阶导数＋多元散射校正（MSC）预处理后,选择7502-5446 cm^-1、4601-4247cm^-1和6102-4597 cm^-1区间建立样品纤维素、戊聚糖、Klason木质素含量和光谱数据之间的相关性模型。模型的决定系数（R2）高,分别为0.9705、0.9927和0.9827;交叉验证均方根偏差（RMSECV）低,分别为0.40%、0.38%和0.49%;残留预测偏差（RPD）分别为5.83、11.7和7.61。采用3个模型分别对样品进行预测,预测偏差分别为-0.36%-0.34%、-0.40%-0.32%和-0.36%-0.39%。结果表明,可以利用近红外光谱法快速测定木材纤维素、戊聚糖和Klason木质素含量。     

硫酸盐法蒸煮脱木素历程的近红外光谱表征法

利用近红外光谱法对木材硫酸盐法蒸煮过程脱木素历程进行了研究。结果表明,利用红外光谱能较好地表征木材的三段脱木素历程。这为下一步近红外光谱在线测量仪的开发奠定了理论基础。     

Transition characteristics of Brazilian vegetable fibers investigated by heating microscopy

ABSTRACT

Structural studies of three vegetable fibers plus eucalypt wood through heating microscopy, Fourier transform infrared spectroscopy, X-ray diffraction (XRD), and thermal analysis through Thermal Gravimetric Analysis/Differential Thermal Analysis are presented in this work. Morphological and dimensional changes obtained from heating microscopy were observed, showing shrinkage occurrences of vegetable fibers related to their diameter and length, respectively. The thickness decreased by 50% when heated at 450–500°C, this process starting at 300–400°C with an initial percentage length of ≈ 90%, that corresponds to a fast weight loss. These results were compared with simultaneous thermal analysis under the same conditions. Thus, for the first time, it was possible to quantify vegetable fiber dimensional changes and surface aspects under heating that cannot be seen by traditional thermal analysis. We also performed crystallinity calculations from XRD data, observing that cellulose/hemicellulose contents had major contribution in all samples.     

Untersuchungen der Faserlänge der Serbischen Fichte von Mittelgebirgsstandorten

This article describes measurements of fiber length, density, bending and compression strength on wood of 14 trees of Serbian spruce from Saxonian and Thuringian stands. The age of the trees varied between 22 and 54 years. The average fiber length of the wood fibers as well as the average values for late and early wood were determined. As expected latewood fibers are longer then earlywood fibers. Besides the absolute age of the tree also the age of the yearrings is affecting the fiber length. Up to an age of 54 years fiber length increases in parallel with the age. Relationships between fiber length, increases in parallel with the age. Relationships between fiber length, density and strength properties could not be satisfactory evaluated.     

THE APPLICATION OF TRANSMISSION NEAR INFRARED SPECTROSCOPY TO THE ANALYSIS OF WORTS

Transmission near infrared spectroscopy has been evaluated for the analysis of ‘laboratory’ worts. Good agreement between manual and near infrared methods has been obtained for Hot Water Extract and total carbohydrates. Satisfactory calibrations have been developed for fermentable sugars, fermentability and free alpha-amino nitrogen. No sample preparation was required. Hence, this technique provides a rapid and non-destructive method for measuring all these parameters simultaneously.     

竹原纤维和亚麻纤维鉴别分析方法研究

竹原纤维和亚麻纤维理化性质极其相似，常规方法中难以找到合适的鉴别方法，文章采用纤维投影法、密度法、溶解法、傅立叶红外法等多种方法分析研究，根据亚麻和竹原纤维分子结构中-CH、-CH2、-CH3个数（聚合度）的差异，利用红外光谱仪测其光谱图，发现在2900cm^-1和2850cm^-1处存在较为明显的差异，经多次测量完成竹原纤维的标准红外光谱图，利用此光谱图可以定性鉴别亚麻和竹原纤维。     

Determination of fiber length and juvenile and mature wood zones from Hevea brasiliensis trees grown in Brazil

The aim of this study was to verify the average fiber length and the juvenile and mature wood zones from Hevea brasiliensis proveniences from a reforestation area in Sao Paulo, Brazil. For this purpose, five Hevea brasiliensis trees were randomly collected from a 50-year-old plantation, located in Balsamo, Sao Paulo, Brazil. The trees were cut and five flat sawn boards were obtained. The juvenile and mature wood zones were determined by fiber length measurement from the pith to the bark. The results showed that: (a) the juvenile wood of this species occurred approx. between 40 and 55 mm, from the pith, and from this point forward, the mature wood zone was found; (b) there was a significant difference between the average fiber length of juvenile wood (1.26?mm) and mature wood (1.51?mm).