枣中糖测定的研究进展

综述了枣中糖的分离、提纯和测定的研究进展，并对目前研究存在的问题及以后的发展前景进行了讨论。     

工业废水新型混凝剂的研制

聚合硫酸铁是一种新型无机高分子混凝剂。它是以硫酸酸洗废液和废铁屑为原料,以废治废,成本低,制造和使用简单。在处理工业废水的效果上优于其它混凝剂,有广阔的应用前景.     

木材纤维与回收聚丙烯的热压复合工艺研究

研究了热压时间、热压温度、聚丙烯和偶联剂加入量等工艺因子对木材纤维和回收聚丙烯复合材料性能的影响。确定了压制密度为0．80g／cm3、10mm厚的木塑复合材料的最佳工艺条件为:热压温度175℃、热压时间8min、塑料加入量40％、偶联剂的加入量4％。在此条件下压制的木塑复合板材,物理力学性能中的内结合强度和吸水厚度膨胀率与中密度板的国家标准相比达到优等水平,静曲强度和弹性模量基本满足中密度板的国家标准要求。     

Variation in infiltration with landscape position: Implications for forest productivity and surface water quality

Variation of infiltration rates with landscape position influences the amount, distribution, and routing of overland flow. Knowledge of runoff patterns gives land managers the opportunity to affect changes that optimize water use efficiency and reduce the risk of water quality impacts. The objective of this study was to assess the effect of landscape position and associated soil properties on infiltration in a small (147 ha) forest/pasture watershed in the Ozark Highlands. Three previously reported studies measured infiltration rates using double ring, sprinkling, single ring, and tension infiltrometers on soils at varying landscape positions. Although large variation in infiltration rates was observed among measurement techniques, upland and side slope soils (Nixa and Clarksville) had consistently lower infiltration rates compared to the soil in the valley bottom (Razort). A conceptual understanding of watershed runoff is developed from these data that includes infiltration excess runoff from the Nixa and Clarksville soils and saturation excess runoff on the Razort soil. Management of the soil water regime based on this understanding would focus on increasing infiltration in upland soils and maintaining the Razort soil areas in forest. Forest productivity would be enhanced by increasing plant-available water in upland soils and decreasing flooding on the Razort soil. Surface water quality would be improved by reducing the transport of potential water contaminants from animal manure applied to upland pastures.     

竹笋象危害对竹材物理力学性质的影响

对受笋万纹象(Otidognathus rubriceps Chevrolot)、一字竹笋象(O.davidis Fairmaire)、大竹笋象(Cyrtatrachelus longimanus Fabricius)危害后断梢毛竹、竹腔注药防治后毛竹、正常毛竹3种竹材进行竹材抗弯强度、抗弯弹性模量和顺纹抗拉强度测定结果表明,与正常毛竹相比较,受竹笋象危害断梢毛竹差异显著,3个竹材物理力学性质指标分别下降了43.79%、39.01%、29.28%,竹腔注药防治后毛竹3个指标下降了13.87%、10.95%、9.01%,但差异不显著,不影响竹材的使用价值.     

抚育间伐对落叶松云冷杉混交林的影响

以15块人工落叶松纯林演化后形成的落叶松云冷杉混交林为对象,间伐后12年观测结果,研究间伐对林分和树木生长、树种组成、物种多样性及土壤等因子的影响。间伐强度分为2级:中度(平均为20%)和强度(平均为30%)。结果表明:间伐促进了保留木生长的显著增加,但不同间伐强度间无显著差异。林分及单木的直径、断面积和蓄积生长率均表现相同的趋势即随间伐强度的增加而增加。但间伐没有显著地增加12年间的总收获量。伐后对照样地表现为较高的枯损,枯死木主要是落叶松和阔叶树。林分进界株数严重不足,进界的主要树种是云冷杉、阔叶树和红松,以耐荫树种为主。从枯损和进界看,如果能对红松和阔叶树进行保护,这种林分很可能逐渐演化为阔叶红松林。建议对红松和阔叶树进行保护,使林分向阔叶红松林方向发展。各林分的树种组成在12年间基本没有发生变化,即间伐没有显著地改变林分的树种组成,目前的树种组成即落叶松、其他针叶树(云杉、冷杉和红松)和阔叶树组成比约为6∶3∶1可能是相对稳定的群落。20%和30%的间伐强度没有显著地改变林分的物种多样性、灌草生物量和土壤物理性质,间伐样地的物种多样性略有提高;间伐样地的土壤物理性质有所改善,总孔隙度和毛管孔隙度都大于对照;林下灌草生物量有所增加。     

广西大青山石灰岩山土壤理化性质的演变及其造林绿化

研究得知:该范围的石山(石灰岩山)上,在北热带气候及植被条件相互作用下,演变为一类特别肥沃的土壤——石灰土;该类土壤有机质及氮素丰富,保蓄水性能强;钙、镁、钾、铁、锰、锌等元素含量也十分丰富,故称“热带黑钙土”;石山石多土少,整体环境恶劣,而局部生境却十分优越,又因该区雨量充沛,即使石山中的石缝、石槽内,只保存5％土质,上面就会覆盖较繁茂的草、灌植被,其中不少具有较高的经济价值,同时,也易于栽培喜钙、喜肥的优良或珍贵树种。     

日本龟蜡蚧在枣树上的发生与危害

１９９６年８月￣１９９７年６月，在陕西大荔县八鱼乡西营村和蒲支县平路庙乡直杜村调查了日本龟蜡蚧在枣树上的分布与危害。结果表明，单叶幼虫数随枣树受害程度的增加而增加，单果重随枣树爱害程度的增加而减少，越冬雌虫的危害造成每股的抽吊数减少，吊长显著变短，每吊的刺树数减少，幼虫和雌成虫在树冠上的分布是阳面（南面）大于阴面（北面），其中树冠中部虫量分布的最多。     

Variations in soil chemical properties and microbial biomass in artificial gaps in silver fir stands

Changes in soil chemical and microbiological parameters in small (185 m²) and medium (410 m²) gaps, created in mature silver fir (Abies alba Mill) stands (mean height 30 m) in the Calabrian Apennines (Southern Italy), were studied over 2 years. Medium gaps had high soil temperature and photosynthetically active radiation (PAR) transmittance and low soil moisture. Within small gaps we detected a greater amount of organic matter, with respect to under canopy cover sites and medium gaps. Moreover, a different trend of the organic matter between small and medium gaps was observed. In the medium gaps, with respect to under canopy cover sites and small gaps, we found a relatively low content of organic matter, associated to a lower amount of humic acid, which suggested that the organic substrate undergoes a mineralization rather than a humification process. An opposite trend was observed in small gaps, where the increase of organic matter content, associated to an increase of humic acid and microbial biomass, suggested a better humification process. Moreover, in small gaps the highest level of urease and the greatest fluorescein diacetate (FDA) hydrolysis were observed. The different trend of organic matter observed in small and medium gaps may be related to changes in the environmental conditions. PAR transmittance, significantly higher in medium gaps, contributed to increase soil temperature and decrease soil moisture, affecting soil microbial populations and organic matter trend. These results suggest that the creation of small gaps represents the silvicultural practice with minor environmental impact.     

原料表面碱液处理对稻草碎料板力学性能的影响

在实验室条件下探索了稻草原料表面碱液处理对稻草碎料板力学性能的影响.试验表明,处理后的稻草碎料板的内结合强度比处理前有大幅度提高,弯曲弹性模量和静曲强度比处理前则有所下降,但都达到了相关的国家标准;2h吸水厚度膨胀率升高,超过国家标准.因此稻草表面碱液处理提高了稻草原料表面润湿性和胶合强度,但对稻草碎料板的力学性能有影响.