咖啡园的混作

<正> 混作的表述很多,如多样化栽培、群作、间作或多层栽培,就是意味着在同一块土地栽培两种和两种以上的一年生作物。从技术上讲,多样化栽培表明与原来种植一种作物的方法不同,而要使其多样化。群作是把两种或两种以上的多年生作物同时种植在同一环境里。间作是在长期作物中间栽培一些短期作物。而多层次栽培,就是在同一土地上栽培不同的作物,以最好地利用土地,获得最好的经济产品。总之,所有上述的耕作方法,都是为了利用好现有的土地和资源,使种植者获得最好的经济收益。     

Electrophysiological and Behavioral Responses of Adult Anoplophom glabripennis (Motschulsky) to Volatile Components of Host-Plant

Electrophysiological and behavioral responses of adult A. glabripennis (Motsch.) to volatiles from ashleaf maple (Acer negundo L.) were investigated to identify semiochemicals involved in host location. Measurable electroantennogram (BAG) responses were elicited to all compounds tested, the most effective antennal stimulants were trans-2-hexen-1-al,decyl aldehyde and trans-2-hexenl-ol.These profiles were similar between males and females. In Y-tube olfactometer bioassays, above three compounds with certain concentration, trans-2-hexen-l-al (1%), trans-2-hexen-l-ol (1%) and decyl aldehyde (10%), were significantly attractive to the adults in laboratory. The results show that either BAG or olfactory responding to a particular volatile compound are markedly influenced by the concentration.     

Decay Detection of Ancient Wood Rafters in Tibet by Stress Wave Testing Method

Visual classification and stress wave non-destructive testing technology were adopted to evaluate the decay status of ancient Populus wood members （rafters） replaced from the Potala Palace. The decay status of wood members was evaluated by stress wave testing and visual observation. For most of the ancient wood members, the evaluation results by two methods were consistent with each other. Also stress wave testing techniques can find the internal wood member decay to eliminate the hidden hazard for ancient wood members, and offer relatively accurate quantitative information for the safety status of ancient wood members. Thus during the maintaining for ancient architectures, visual observation combined with stress wave testing techniques is a good way to evaluate the degradation of ancient wood members.     

榆树种和杂种间的可交配型及形态变异

本文报道了1970、1971、1972和1973年关于榆树的培育研究,主要目的是:(1)测定种和杂种之间潜在的可交配性;(2)对已表现出一个或更多有价值特征的优越性,诸如抗病、生长速度、类型(form)的基因型进行杂交;(3)对由杂交产生的全部后代在遗传性的可靠性上作出估价。许多用于杂交的亲本是荷兰榆树培育计划中得到的无性系,我们将这些无性系用于荷兰培育工作并从 F_3代中选优。     

圆锯纵锯时前斜角对切削精度和切屑形成的影响

1.问题的提出在木材加工工业中,把原木加工成规格材时通常用带锯先锯剖出大方,再用园锯加工。在这加工过程中,产生了大量的无市场价值的锯末。有些锯末用来作纸浆的原料。为了利用锯末中的木材纤维,以给予最后的纸浆产品足够的强度。那么在锯切过程中,我们首先期望能加工出高的精度,满意的加工表面,以使能从一定的原木中获得最大量的锯材,其次期望所产生的锯末有好的纤维性能,以增加锯末对于纸浆工业的市场价值。     

竹子组培苗试管内超早期开花结实

竹子开花很少,而开花后则死亡。因此,很难获得竹种。为此,采用组培法促进竹子开花结实。对刺状箣竹和苏麻竹进行组培,取得了开花结实的结果。这一技术为竹类杂交育种铺平了道路。     

用量纲分析建立生长和收获模型

生长和收获模型的建立始于Mackinney和Chaiken,1939年他们把多元回归技术用于收获预测做了开拓性工作。从此以后,建立了许多基于单株木和林分的预测森林资源生长和收获的模型。由于更精确的统计技术、数据库的发展以及计算机功能和效率的提高,模型的复杂程度也增加了。     

阔叶材(山杨和速生杨)漂白浆和未漂浆水解降解及其产物性质的研究(英文)

本文研究了木素含量为0.2—1.2％的山杨和速生杨漂白浆和未漂浆的水解降解过程。研究结果表明,该过程与先前已研究过的其它种类的木浆具有相类似的特点,即水解过程存在两个明显的阶段(快速降解阶段和缓慢降解阶段),最终纤维素降解至“极限”聚合度。由不同原料用不同方法制成的不同种类的浆,其水解速度以递减的顺序排列为:山杨浆(漂白浆和未漂浆)→白桦浆→速生杨浆(漂白浆和未漂浆)→针叶材硫酸盐浆→针叶材亚硫酸盐浆(3.7×10~(-4)/分,1.7×10~(-4)/分→1.6×10~(-4)/分→1.3×10~(-4)/分,0.9×10~(-4)/分→1.2×10~(-4)/分,0.8×10~(-4)/分) 水解后纤维索达到“极限”聚合度,后者大小取决于原料种类。山杨硫酸未漂浆分别为206和135;氧碱法山杨浆为160;速生杨硫酸盐未漂浆和漂白浆分别为250和240。水解后试样呈白色粉末状,得率82～85％。试样以其吸水能力为显著特征。未经超声波分散作用的试样,其吸水值比原浆低(从未漂浆90～115％和漂白浆75～95％降至70～80％)。反之,于水中经超声波分散作用后,试样的吸水值急剧增大(山杨微晶纤维素为160％,速生杨微晶纤维素为260％),接近于桦木浆和棉浆微晶纤维素的水平。对原浆纤维和微晶纤维颗粒形状和大小进行了显微观测。测得的数量分布微分曲线表明,在酸水解     

Wood Microstructure Effects on Chinese White Poplar Dyeing

In order to study the influence of wood microstructure on wood dyeing, eleven parameters of wood microstructure and 5 parameters of wood dyeing effects for 34 pieces of wood boards from 5 trees of Chinese white poplar (Populus tomentosa) were determined and the multiple regression analysis between the factors of wood microstructures and the parameters of wood dyeing effects were made. The regression results show that each variable of wood dyeing effects has higher relationship with wood microstructures, and multiple correlation coefficients between each variable of wood dyeing effects and wood microstructures are 0.483 6~0.799 8. The main factors of wood microstructures influencing wood dyeing of Chinese white poplar are proportion of wood ray, proportion of vessel and proportion of wood fiber according to comparing the standardized regression coefficients of multiple regression equation.     

Use of Near Infrared Spectroscopy to Measure Mechanical Properties of Solid Wood

The visible and near infrared （NIR） （350-2500 nm） spectra and the MOE of 438 small clear wood samples from Chinese fir, eucalyptus and poplar 72 were measured. Using partial least-square （PLS） modeling, the NIR spectra could be used to predict MOE and MOR of the clear-wood samples from Chinese fir and eucalyptus solid wood. NIR spectra could only be used to Predict MOE but not MOR of poplar clear-wood samples. With the exception of MoR of poplar clear-wood samples, the correlations between NIR and the mechanical properties are very strong, and the calibration and test correlation coefficients are both above 0.80.