木材原料中金属离子的测定及分布的研究

利用原子吸收光谱测定了有代表性的几种针叶木和阔叶木原料中金属元素分布及含量,并利用扫描电镜—能谱仪分析了原料的不同部位中金属离子的分布规律。结果发现在实验范围内,各种木材原料中都存在由多种金属离子构成的复杂体系;不同种原料中金属离子的含量和成分存在着很大差异;针叶木Ｆｅ、Ｍｎ 含量显著,高于阔叶木;同种原料中,边材金属离子含量一般高于心材;不同生长环境会导致木材金属离子分布出现差异。纸浆中的金属离子主要来源于原料本身,因此对金属离子含量不同的原料,纸浆漂前的除过渡金属离子预处理条件应该不同。     

心材比例对亮果桉硫酸盐浆性能的影响

把亮果桉的心材和边材分离,分别测量了每种材的物理性质和化学性质。心材和边材的密度相似,但边材平均纤维长度比心材长12.6%,其纤维壁比心材的厚。在化学成分上最重要的差异是,心材木素比边材多15%,半纤维素多20%。把心材和边材的木片按一定比例混合进行硫酸盐法制浆,评价了黑液和纸浆的性能。研究发现,与纯边材浆相比,纯心材浆的抗张指数、耐破指数更高,而撕裂指数和松厚度较低。心材比例超过50%会带来更高的卡伯值,并使浆渣含量增加。     

落叶松木素的特性

用红外、紫外光谱仪,元素分析仪、~1H-NMR、~(13)C-NMR和化学分析方法,对落叶松心材木素特性进行了研究,与边材和云杉相比,心材MWL含有更多的酚羟基、醌、共轭羰基和缩合芳环结构,它们与苯环形成了复杂的共轭发色体系。心材木素中含有不可抽提的双氢黄酮类多酚物质。文中还介绍了落叶松木素在磺化和漂白过程中的一些特性。     

白腐菌预处理对杨木心材双螺杆APMP制浆特性的研究

对杨木心材进行了白腐菌预处理双螺杆APMP制浆的研究,探讨了杨木心材经白腐菌预处理前后双螺杆APMP浆料纤维形态和物理性能。结果表明,杨木心材在经白腐菌预处理后,木片中的Klason木质素和酸溶木质素的含量均减少。通过用双螺杆挤碾处理后进行APMP法制浆,所得浆料的纤维平均长度显著提高,细小纤维含量下降,扭结指数有所增大。成纸的紧度、环压指数、耐破指数、抗张指数、撕裂指数分别提高了15.6%、5.8%、15.8%、37.3%以及8.4%。研究结果进一步表明,白腐菌预处理杨木心材双螺杆APMP浆经两段H2O2漂白后,浆料白度达74.4%,但与未用白腐菌处理时的浆料白度（76.9%）相比,白度有小幅下降。经过白腐菌预处理之后,杨木心材双螺杆APMP浆的纤维长度整体提高,说明白腐菌预处理后的纤维形态更利于提高成纸的强度性能。     

木材原料中金属离子的测定及分布的研究

利用原子吸收光谱测定了有代表性的几种针叶木和阔叶木原料中金属元素分布及含量并利用扫描电镜一能谱仪分析了原料的不同部位中金属离子的分布规律。结果发现在人,各种木材原料中都存在由多种金属离子构成的复杂体系;不同种原料中金属离子的含量和成分存在着很大差异;     

2016年我国木材与木制品市场概述

据中国木材与木制品流通协会信息中心对全国木制品制造业重点企业采购经理人调查问卷显示,2016年我国木制品产业生产增速平稳,国内市场需求较稳定,国际市场需求疲软,出口下滑,主要木材原料及木制产品价格较年初有所下降,下半年开始回升,行业经济效益明显改善。     

山地杨边材和心材差异性分析

分析了山地杨原料边材和心材的物理性能、纤维形态、化学组成、解剖结构等方面的差异性,探讨了这些差异性对其制浆造纸性能及流体传输性能的影响。结果表明:原料边材具有孔隙度大、纤维较长、长宽比大、壁腔比小、抽出物含量少、木素含量低、综纤维素含量高、毛细管通道清洁、沉积物少等特点,其制浆造纸性能明显优于心材。同时,研究表明边材的流体传输性能明显优于心材。     

桦木小木制品的加工

桦木小木制品的加工桦木原是一种经济价值不高的树种，随着对以桦木为原料小水制品的开发，桦木一跃而成为经济价值较高的树种，以桦木为原料的小木制品也因其畅销国外，经济效益高、上得快而成为出口创汇的理想产品。卫生筷子卫生筷子主要以白桦木为原料，也有用杨木的。...     

喷雾干燥法制备生姜微胶囊的研究

以生姜为原料,经乙醇提取而得的姜油树脂为心材,以阿拉伯胶和麦芽糊精为壁材,用喷雾干燥法来制取姜油树脂微胶囊。通过正交试验分析,以油树脂包埋率为指标,确定了生姜喷雾干燥法微胶囊化的最佳工艺条件:心材与壁材比为1∶5、进风温度190℃、阿拉伯胶与麦芽糊精比为1∶7。     

微胶囊化粉末猪油壁材的研究

<正> 所谓微胶囊技术是指利用胶囊或膜将核心物质如油脂、香料或调味料等食品成分或食品添加剂包埋,使之与外界环境隔绝,在适当时候再释放出来。其中,被包埋的物质称为心材,实现微胶囊化的物质称为壁材。一般通过微胶囊技术生产出来的壁材,能发挥各种不同的功能,如减轻外界环境如光、氧、温度、pH值等对敏感心材的影响,提高储存性能;改善心材的可操作性能如防止结块,提高与其他物料的混合性,实现由液态向固态的转化,提高其流动性等;控制心材的释放;掩盖心材的异味。     

速生杨芯材与枝桠材木片P-RC APMP法制浆性能对比

通过对杨木芯材和枝桠材P-RCAPMP法制浆生产使用性能对比,得出在木材原料紧张的情况下,芯材和枝桠材同样可以用于生产,并通过相应的处理,可以很好地提高产品质量,达到节能降耗的效果。     

烘烤强度和木纹理对橡木（Quercus petraea）心材多酚和香气的影响

考察不同烘烤程度对不同纹理橡木心材试样中低分子质量酚酸和挥发性物质含量的影响,结果表明烘烤过程将会改变橡木心材的物质组成,并通过相应的化学反应增加挥发性物质的含量。同时,在不考虑烘烤强度条件下,供试的细纹理橡木心材试样含有较高的挥发性物质含量,例如顺/反橡木内脂、顺/反异丁子香酚、呋喃醛、紫丁香醇,以及芥子醛、松柏醛、香草醛和丁香醛等低分子质量酚类化合物,而中纹理和粗纹理的样品则表现出较高的总酚、总单宁水平,以及较高的鞣花酸和没食子酸含量。此外,主成分分析显示,中纹理和细纹理样品的中度和重度烘烤处理与橡木心材试样的挥发性物质含量有较大的正相关性,而粗纹理的未烘烤和轻度烘烤样品则与试样中总单宁和阿魏酸含量呈正相关。     

Artocarpus lakoocha heartwood extract as a novel cosmetic ingredient: evaluation of the in vitro anti-tyrosinase and in vivo skin whitening activities

The heartwood extract of Artocarpus lakoocha Roxb. was evaluated for the in vitro tyrosinase inhibitory activity and the in vivo melanin-reducing efficacy in human volunteers. The IC(50) of the extract and oxyresveratrol, its major active ingredient, against mushroom tyrosinase was determined to be 0.76 and 0.83 mug mL(-1), respectively. The extract dissolved in propylene glycol was subsequently tested in female volunteers using a parallel clinical trial with self-control (n = 20 per group). The first group received the 0.25% w/v A. lakoocha solution as the test solution, whereas the second and the third group, respectively, received 0.25% licorice extract and 3% kojic acid as the reference solutions in the same solvent. The subjects in each group twice daily applied the test (or reference) solution in one of her upper arm, whereas the remaining arm was treated with only propylene glycol (self-control) for 12 weeks. The melanin content of each application site was measured using Mexameter every week and calculated as % reduction in melanin content relative to the initial melanin value (% whitening). The value of % whitening was then compared between the product-treated and the propylene glycol-treated arms within the same subject using paired t-test (alpha = 0.05). The A. lakoocha extract was the most effective agent, giving the shortest onset of significant whitening effect after only 4 weeks of application (P < 0.05), followed by 3% kojic acid (6 weeks) and 0.25% licorice extract (10 weeks). The effect also increased with time with maximum whitening observed at week 12 for A. lakoocha extract. When the extract was formulated as an oil-in-water emulsion, its whitening efficacy was further enhanced. Daily application of 0.1% w/w A. lakoocha lotion to the upper arms (n = 25) and cheeks (n = 15) of volunteers produced significant whitening over the lotion base after 2 and 3 weeks, respectively (P < 0.05). Thus, the preliminary study suggested that the heartwood extract of A. lakoocha may have a promising potential for use as an effective and economical skin-whitening agent.     

Variation of certain chemical properties within the stemwood of black locust (Robinia pseudoacacia L.)

From the bottom, middle, and top of three mature 35 to 37-year old black locust tree discs were cut and analysed to determine the variation within the stem of certain chemical properties. Hot-water extractive content was greater in heartwood than in sapwood, while the reverse occurred for the dichloromethane extractive content. Vertical stem analysis of hot-water extractives showed that they increased in heartwood but decreasedin sapwood from the bottom to the top of the stems while the reversal occurred for dichloromethane extractive content of sapwood. At the bottom and the middle of the stems, ash content was greater in sapwood than in heartwood, but at the top no difference was found between heartwood and sapwood. Ash content of both heartwood and sapwood was found to increase in the axial direction with respective values of 0.36% (bottom) and 0.76% (top) for heartwood and of 0.65% (bottom) and 0.76% (top) for sapwood. Ash analysis showed that considerable variations were found for the inorganic elements K and P being greater in sapwood than in heartwood. Heartwood was more acid than sapwood except for the top of the stems. Acidity mean values were found to increase from the bottom to the top of the stems in heartwood while they slightly decreased in sapwood. Total buffering capacity of heartwood was greater than that of sapwood and total buffering capacity of sapwood exhibited an inverse relationship to height. Very small acid equivalent values were determined only in sapwood. At the bottom, lignin content in heartwood (25.73%) was greater than in sapwood (18.13%). Lignin content of heartwood decreased from 25.73% at the bottom to 18.33% at the top, while that of sapwood was 18.13% at the bottom, 21.42% at the middle and 19.64% at the top.     

不同品质桉木的制浆造纸性能分析

本文对几种不同产地的实心和空心桉木的制浆造纸性能进行分析.就纤维形态而言,总体上实心材的纤维长度和宽度均大于空心材,而长宽比小于空心材.化学成分分析表明,实心材的木素含量较少,碳水化合物含量较高.实心材的高锰酸钾值较低,得率稍低.经过漂白和打浆后,不同产地原料间的差别更加明显.     

Primer cure and adhesion after light organic solvent preservative treatment of Radiata pine

This study examined the effect of preservative treatment and wood drying history on paint primer cure and adhesion for New Zealand radiata pine (Pinus radiata D. Don). Double Vacuum LOSP treatments resulted in a significantly lower LOSP uptake than did Lowry treatments, for both sapwood and heartwood. Wood drying history had no effect on uptake by sapwood, but did affect uptake by heartwood; high-temperature-kiln-dried heartwood retained more solvent than air-dried or conventionally dried heartwood. For sapwood, LOSP treatment method and wood drying history did not significantly affect either primer cure or primer adhesion. For heartwood, primer adhesion in the early stage of cure was better with Double Vacuum treatments. Double Vacuum treatments also resulted in a higher cure of primer, two days after priming, than did Lowry treatment when either conventionally or high-temperature-kiln-dried heartwood was used, but no significant difference was found with air-dried heartwood. It was concluded that, for radiata pine heartwood, Double Vacuum treatment, combined with either air-drying or conventional drying, will reduce LOSP uptake and give better primer performance, so long as effective ventilated solvent removal is achieved before priming.     

Heartwood detection in Scots pine by means of heat-sensitive infrared images

Automatic heartwood detection will improve the ability to produce timber of prescribed properties and increase sawmill revenues. In fresh crosscuts, evaporation cools the surface more in the moist sapwood than in the drier heartwood areas. In this semi-industrial investigation, infrared exposures of 180 pine sawlogs were analysed. An algorithm was established to determine the heartwood diameter fraction in a digital temperature profile through the crosscut. Top end heartwood diameter could then be computed automatically by multiplying top end diameter (measured by a traditional log scanner) with the heartwood fraction calculated from an infrared exposure taken at an arbitrary end. The temperature gradient between the heart- and sapwood indicated the accuracy of the method. A promising application would be to use the heartwood fraction to estimate mean annual ring width and other related wood properties, and to use the temperature gradient to indicate the log freshness.     

Zum Verhalten des Splint- und Kernholzes der Lärche (Larix decidua) bei der Herstellung von feuchtebeständigen Spanplatten unter Einsatz verschiedener Bindemittel

Chips from sap- and heartwood of 20, 40 and 102-year-old larch (Larix decidua) were prepared and chemically characterized. From the chips one-layer boards of 20 mm thickness were prepared using melamine-urea-phenol-formaldehyde resin (MUPF-resin), phenolformaldehyde resin (PF-resin), polymeric diisocyanate (PMDI), and tannin-formaldehyde resin (TF-resin). The physical and chemical properties of the boards were determined. Moreover, the influence of hot water extractives on the pH-value, viscosity and gelation time of the resins was assessed. Sap- and heartwood chips are different in their chemical properties as well as in bonding behaviour. The age of the tree has also an influence on the bonding characteristics of the chips. Thickness swelling, water absorption and equilibrium moisture content of heartwood boards were always lower than those of sapwood boards. Moreover, bending and internal bond strength of heartwood boards made from 20- and 40-year-old trees are much higher than those produced from sapwood. The strength properties of the boards deteriorate, however, with increasing age of the tree. This applies for both heartwood and sapwood boards. The water extractives of heartwood boards are of lower pH-value and higher buffering capacity than the corresponding boards from sapwood. Moreover, the emanation of acetic acid from heartwood boards is much higher than that of formic acid. In addition, boards from heartwood are in general of lower formaldehyde release compared with boards from sapwood. The addition of heartwood extractives to MUPF-resin increases the viscosity and gelation time of the resin and decreases its pH-value, whereas in case of PF-resin no such increase in the gelation time was registered. The extracts of heartwood increase the viscosity and gelation time of TF-resin.     

Die Verteilung der Extraktstoffe im Stammholz von Pinus sylvestris L.

Yield and composition of extractives from sapwood and heartwood ofP. sylvestris differ greatly. While neutral lipids dominate in sapwood, free resin and fatty acids are the main constituents in heartwood. The extractive content in heartwood decreases with increasing trunk height. Beside the lipophilic components in the petrol ether extracts, carbonhydrates, low molecular lignin precursors and stilbene phenols (from heartwood only) can be obtained with more polar solvents.     

Heartwood of Cupressus lusitanica, C. macrocarpa, Leyland and Ovens cypress and prediction of its durability using near-infrared spectroscopy

The heartwood of plantation-grown Cupressus lusitanica, C. macrocarpa, Leyland and Ovens cypress (×Cuprocyparis leylandii and ×C. ovensii) from trials in New Zealand, was evaluated using breast height increment cores and in vitro decay tests with fungal cultures to determine the variation in the heartwood content and natural durability, and its prediction using near-infrared (NIR) spectroscopy. The increment core measurements showed the length of the cores was strongly influenced by the stocking and site, but the heartwood content and weight loss with decay testing were strongly influenced by species and genotype. The heartwood content was consistently high for C. macrocarpa, but varied widely for C. lusitanica, and the Leyland and Ovens cypress clones. The weight loss was similar for the species and cypress clones, with the heartwood classified as very durable and durable, but there were differences in the distributions of less durable heartwood. The NIR calibration models of mass loss with fungal decay testing had ratios of prediction to deviation (RPD) of 1.0–1.3, which suggests the models could be used to segregate the heartwood for high and low values of natural durability.