桦木造纸获成功

桦木造纸获成功吉林造纸厂经过多年研究，应用桦木制浆、造纸获得成功，通过了轻工业部的鉴定。该厂用桦木生产出的胶印新闻纸，经《人民日报》、《工人日报》等报社试用，证明印刷性能和质量完全达到高速胶印机的要求。桦木是一种储量丰富的廉价树种，应用桦木造纸，每吨...     

桦木纤维特征及其在纸和板中的应用

桦木与针叶材的纤维持征比较及桦木硫酸盐浆在不同品种的纸和纸板中的应用。     

国外桦木制浆造纸

随着长纤维的针叶材原料的日益短缺,对于短纤维的阔叶材利用已引起世界各国造纸工业界的广泛重视.从原料来源、木材纤维形态和化学组成看,行家们普遍认为桦木是造纸工业中有广阔前景的一种阔叶材原料.因此,开发利用桦木造纸工艺已成为盛产桦木国家的重要研究课题.     

挤压预处理对杨木APMP浆纤维形态及制浆性能的影响

在相同的APMP制浆工艺条件下,以未挤压木片为对照样,考察了双螺杆挤压(TSE)和单螺旋挤压(MSD)对纸浆纤维形态及制浆性能的影响。研究结果表明:在相同制浆工艺下,挤压程度越高,纸浆的长纤维及纤维束含量越低。当加拿大游离度为250 mL时,TSE挤压所得纸浆含纤维束1.78%,相对MSD挤压降低了76.67%。此外,经TSE挤压所得纸浆的耐破强度和抗张强度均高于对照样和MSD挤压;而TSE挤压所得纸浆因长纤维含量较低,使得其撕裂强度低于对照样和MSD挤压。当加拿大游离度为250 mL时,TSE挤压所得纸浆白度为65.48%(ISO),较MSD挤压提高了9.14%(ISO),较对照样提高12.94%(ISO)。由于TSE挤压后木片浸渍时反应更充分,有更多的物质溶出,因此其所得纸浆得率(84.54%)低于MSD挤压(87.20%)和对照样(87.00%),且制浆过程产生废水的COD和SS值均较高。     

造纸的好原料——桉树

欧洲多用桉树制浆,其原因主要是纸的质量和性状好,湿纸强度与桦木生产的纸相同,优于北美的阔叶树。巴西1868年开始用桉树制浆,比智利、阿根廷和鸟拉圭迟好多年,但现在是世界上最大的桉树种植园,约三百万公顷,1961年第一次用100％的桉树生产印刷纸和书写纸。葡萄牙现已栽植30万公顷蓝桉,另有25万公顷准备栽植,总数55万公顷,所产木材足够生产1.7百万吨/年全漂白浆。目前约生产35万吨/年漂白桉树商品浆。生产能力将从目前的     

构树木质部的纤维形态、化学组成及制浆性能

根据构树的纤维形态和化学组成以及制浆性能的摸索性试验,评估构树制浆的可行性,制定出适合构树制浆的硫酸盐-蒽醌法,并对此法设计L9(34)正交试验。得到结论如下:构树的综纤维素含量为82.09%,Klason木素含量为18.57%,纤维平均长度为863μm,长宽比为51.3,壁腔比为0.37,由化学组成和纤维形态来看,构树是比较适宜制浆的;影响构树制浆得率和卡伯值的主要因素是用碱量,其次是保温时间,硫化度影响最小。制浆的最佳工艺条件是:18%的用碱量,90 min的保温时间和24%的硫化度。     

佯黄竹纤维形态及制浆性能分析

以佯黄竹（Bambusa changningensis Yi et B.X.Li）为研究对象,测定分析了佯黄竹的纤维素含量、纤维形态和制浆性能。结果显示：佯黄竹有较高的纤维素含量（52.54%）、较大的纤维长宽比（111.9）和较高的制浆得率（52.6%）。研究结果表明,佯黄竹可用于制浆造纸,制浆性能优于四川大多数造纸竹种。     

欧美杨107的制浆性能

为给欧美杨107应用空间的扩大提供理论依据,对其木材的化学组成成分、纤维形态、制浆性能及纸张的物理指标进行了测定分析.结果表明:欧美杨107的综纤维素含量为81.07%,硝酸-乙醇纤维素含量为48.59%,木质素含量为z1.08%,1%NaOH抽提物含量为19.39%,欧美杨107的纤维平均长度为1171 um,长宽比为57.54,壁腔比为0.56,且纤维长度呈现正态分布趋势;在保温时间60min,硫化度24%,蒽醌用量0.1%的条件下,对于未漂浆而言,欧美杨107硫酸盐-蒽醌法制浆工艺条件为14%的用碱量,最高温度为168℃;对于漂白浆而言,欧美杨107的制浆工艺条件为16%的用碱量,最高温度168℃;在相同的制浆条件下,用碱量为14%时的纸张综合强度指数较用碱量16%时高.     

小黑杨幼龄材与成熟材制浆性能的比较

以小黑杨幼龄材和成熟材为研究对象,分析比较其化学组成、纤维形态和制浆性能. 结果表明:幼龄材的苯醇抽出物、纤维素、木质素含量高于成熟材,综纤维素含量低于成熟材;幼龄材的纤维平均长度低于成熟材.分别采用硫酸盐法制浆正交试验,分析得出:保温时间、用碱量对幼龄材的纸浆得率和卡伯值的影响非常显著;用碱量和保温时间对成熟材的纸浆卡伯值影响非常显著;在相同蒸煮条件下,幼龄材比成熟材纸浆得率高,卡伯值和聚合度低.     

杨树新品系超短轮伐条材材性及其生物制浆可行性

以多菌种生物制浆工艺为基础,利用10个新选育的杨树无性系为材料,从基本密度、纤维形态、化学成分等方面探索杨树超短轮伐条材生物制浆可行性,结果表明:品种间条材材性差异明显,杨树超短轮伐条材的纤维形态、化学成分等制浆特性均能满足制浆造纸的需求;用1、2 a条材进行生物制浆完全可行,其得浆率为65.0%～72.0%,浆纸质量达国标阔叶木浆的Bk-C标准.     

白桦树皮中桦木醇超临界二氧化碳萃取的研究(英文)

桦木醇,一种药用五环三萜成分,大量存在于白桦(Betulaplatyphlly)树皮中。白桦树皮于2000年9月采集自黑龙江省塔源林场。超临界流体萃取技术(SFE)是一种新型分离技术,广泛用于药物和天然产物生产。本文研究了利用超临界CO2萃取技术从白桦皮中提取桦木醇的工艺条件,系统分析了携带剂用量、萃取压力和萃取温度等参数对桦木醇提取率的影响。结果表明,最佳的萃取条件为:每克桦树皮粉所用携带剂用量为1.5mL,萃取压力为20Mpa,萃取温度为55C,CO2流量为10kg/h,分离压力和分离温度分别为5.5Mpa和50C。图4参6。     

Application of micromechanical models to tensile properties of wood–plastic composites

Wood–plastic composites (WPC) were produced with white birch pulp fibers of different aspect ratios (length-to-diameter), high-density polyethylene, and using two common processes: extrusion or injection molding. Three additive levels were also used: no additive, compatibility agent, and process lubricant. Fiber size was measured with an optical fiber quality analyzer. Tensile properties of WPC were measured and modeled as a function of fiber aspect ratio. Models were fitted to experimental values using the minimum sum of squared error method. A shift from the oriented fiber case (injection molding) to the randomly oriented fiber case (extrusion) was achieved using a fiber orientation factor. Fiber/matrix stress transfer increased with increasing fiber aspect ratio. Stress transfer was reduced with the use of process lubricant. Unexpectedly, the compatibility agent had the same effect. Fiber strength and stiffness contributions to the composite were lower than those of intrinsic fiber properties.     

日本桦树育种研究概况

桦属在日本有9个种,主要分布在本洲北部,其中日本白桦、日本岳桦和棘皮桦3种桦树最为重要,研究的也较多。自1958年以来主要研究了桦树的抗野兔、野鼠特性,以及桦属种间杂交的后代抗野兔、野鼠性的差异,桦属种间杂交和种内杂交其杂交方式不同对种子产量和成活率等的影响;日本白桦、棘皮桦种源试验;日本白桦无性系的测定与早期选择;棘皮桦材质材性的研究。制定了日本桦树的育种战略。     

Growth and chemical composition of silver birch: Comparative study between Lithuania and Romania

The effects of different climatic conditions on growth and chemical composition of Betula pendula in geographically different European regions,Lithuania and Romania,were compared.Birch species in the entire area have a wide natural distribution,but B.pendula is commercially more important in Lithuania than in Romania.Here we evaluated tree ring width,wood density and foliar chemical composition of mature birch trees in two European regions.Trees at the Lithuanian sites had greater radial growth and wood density with no clear changes in foliar chemistry than those at the Romanian sites.Mean wood density was 600-700 kg m~(-3) at Lithuanian and 350-450 kg m~(-3) at Romanian sites.Mean width of wood ring,earlywood and latewood for Lithuanian birch trees were several times higher than the means for Romanian birch trees.We hypothesized that the main differences in birch radial growth and wood density were due to the different climatic conditions in the studied regions.Ca,K and Mg concentrations were significantly higher and Fe and Mn were lower in the birch foliage at the Lithuanian sites compared those at the Romanian sites.Overall assessment of growth showed that silver birch cultivation is more appropriate for colder climate regions and that birch growth may change in the context of a warming climate.     

Discolouration and deformations of birch parquet boards during conventional drying

As a light coloured and relatively hard species of wood, birch is much in demand for wooden floors in Scandinavia. The problem with birch wood is that it easily becomes discoloured during conventional drying. Visual sorting by colour is impossible before the boards are processed into parquet blocks because the discolouration, except for yellowing of the surface, occurs inside the board. In addition to discolouration, harmful deformations occur in birch boards during drying. Colour changes and deformations were compared in birch parquet boards dried according to three different schedules. Received 16 April 1999     

Extraction of betulin from bark of Betula platyphylla by supercritical carbon dioxide extraction

Betulin, which is a medicinal pentacyclic triterpene, is abundant in the bark of white birch (Betula platyphlly). The bark of birch was collected at Tayuan Forest Farm of Jiagedaqi, Heilongjiang Province in September 2000. Supercritical fluid extraction (SFE) that is a new separation technology has been used for the processing pharmaceutical and natural products. In this paper, the extraction of betulin from the bark of birch by supercritical CO2 extraction was studied. The authors investigated and analyzed a few parameters such as modifier dosage, extraction pressure and extraction temperature. The optimal extraction conditions showed that the modifier dosage used for per gram bark powder was 1.5 mL, the extraction pressure was at 20 Mpa, and the extraction temperature was at 55 ℃. The velocity of flow of liquid CO2 was at 10 kg/h. The pressure and temperature in separation vessel were at 5.5 Mpa and 50 ℃, respectively.     

白桦长纤维性状SCAR标记的分析与鉴定(英文)

以东北林业大学帽儿山实验林场天然白桦为研究群体,通过分析其中有代表性的100株个体的纤维长度与RAPD分子标记间相互关联性,筛选出一条与长纤维长度相关性系统为0.6144、显著性达1%水平的片段"BFLR-16",对此片段进行克隆、测序后,并将其转化成与长纤维性状相关的SCAR标记。此标记对长纤维白桦的鉴定效率高达92%,说明此SCAR标记对长纤维个体具有高度特异性,与控制纤维性状长度的基因高度连锁,它的存在与白桦纤维长度的增加有明显的相关性。图6参16。     

青海湟水河流域不同退耕还林模式水文效应

基于野外采样、定点观测和室内实验,研究青海湟水河流域不同退耕还林模式水文效应,结果表明：不同林分类型枯落物有效持水性大小顺序为云杉桦树混交〉桦树〉云杉〉沙棘,其林下土壤持水性大小顺序为云杉桦树混交〉沙棘〉桦树〉云杉〉农田;森林土壤是森林生态系统水文效应的主体,枯落物和土壤总持水性大小顺序为云杉桦树混交〉沙棘〉桦树〉云杉〉农田。不同林分类型枯落物持水量决定于枯落物蓄积量和自然含水率,其林下土壤持水量决定于土壤非毛细管孔隙度。     

完达山林区杨桦林的森林群落特征及经营措施

根据杨桦林生物群落的特性及不同的杨桦林群落类型,论述了不同类型杨桦林的经营和保护措施。     

Reproductive strategies and seeds behavior of Betula platyphylla Suk. Population

Introduction6Birch(BetulaplatyphyllaSuk.)isaphotophilousandbroad-leaftreespecies,whichisdistributedwidelyinthenortheastofChina,especiallyinclearcuttingorburnedforestareasaftertheoriginalvegetationisdamaged(Zhou1986).Birchisjustapioneertreespeciesthroughsecondary-forestsuccession.Sincebirchpopulationoftengrowsrapidlyinalargearea,itusuallyhasagreatamountofseedstorage.Itstimberisanimportantrawmaterialinbuildingmaterials,suchasplywood,veneer,etc..Itsforesightisbroadlyprospectedonexplorationandap…