聚合氯化铝净水剂

聚合氯化铝是一种絮凝剂，在国内外已被广泛地用来净化生活用水、工业用水以及处理工业废水。我单位研制的新聚合氯化铝是用一种新型的生产工艺──“铝矿石硫酸法”，并引入Ａ、Ｂ两种物质，对聚合氯化铝的结构加以改型而成。 该产品与其它絮凝剂相比，具有沉降速度快、絮凝性能好、适应性强、投加剂量少、净水成本低等优点，尤其对高浊度和低温、低浊度水处理效果更显著。产品质量达到国内外同类产品先进水平。该产品可取代硫酸铝净水剂，用于自来水厂，也可替代明矾用于家家户户，同时可用于工业用水、处理工业废水和生活污水，还可用于…     

基于近红外光谱的油茶种子含油量定标模型构建

利用瑞典波通DA7200型固定光栅连续光谱近红外分析仪,对来自不同产地的150份油茶种子样品进行含油量测定.依据其吸收光谱与化学特征分析数据,建立2个种仁含油率模型,并对模型的准确性进行预测评价.结果表明:用整颗油茶种仁建立的模型与常规方法测量结果之间的相关系数为0.88,预测标准偏差为0.91,该模型可用于测定准度要求相对不高而比较珍贵和量少的样品.而用粉碎油茶种仁建立的模型测定效果最好,与常规方法测量结果之间的相关系数为0.98,预测标准偏差为0.33,因此该模型可代替常规测试方法使用.检验结果表明定标模型预测精度高、稳定性较好.近红外光谱技术可用于快速测定油茶种仁含油量,具有很好的应用前景.     

饮用水净水工艺自动控制工艺流程中关键部分设计探讨

原始水处理工艺过程一般都是由人工进行调节和控制的,这种情况下,由于操作人员的经验程度不同的影响,至使水处理过程中,某些因素不同程度地偏离合理的区域,造成处理后水的指标达不到要求或净化成本过高。为降低水处理成本和稳定出水质量,采用自动化控制净水工艺流程是一项克服以上问题的有效措施。下面将整个控制过程中几个关键部分的设计实现思想简要介绍一下。(由于篇幅所限,各部分控制流程图均省略) 一、净水剂投加自动控制部分 投加净水剂是对源水进行净化的第一步工作,这部分采用的是开环数学模型给定和沉淀池出水浊度反馈相     

文冠果

文冠果是我省一种重要的木本油料树。它具有适应性强、用途广、经济价值高等特点,大力发展文冠果,对于贯彻“备战、备荒、为人民”的战略方针,促进工农业生产的发展,壮大集体经济和改善群众生活,都有很重要的意义。一、经济价值文冠果的经济价值很高,被群众称为“一年种,百年收的铁杆庄稼”。其种子含油率为30.8%,种仁含油率52—66%,土法榨油出油率达25%。文冠果油呈橙黄色,似芝麻油,是一种很好的食用油,还可作为高级润滑油、增塑剂、油漆和肥皂等工业用油。油渣含有丰富的蛋白质(种仁含蛋白质26—29.7%)和淀粉(种仁含     

锯末蔗渣不同配比栽培基质对辣木产量的影响

以多油辣木改良品种PKM1为试验材料,以锯末和蔗渣不同配比的7种栽培基质进行大棚辣木栽培试验,结果表明:7种栽培基质的辣木生物产量均高于园土栽培的对照,锯末∶蔗渣=1∶1处理的辣木产量最高,极显著高于对照,显著和极显著高于其它处理,可推荐作为辣木大棚栽培基质。     

湿地松、马尾松幼林化学除草技术的研究

为了改变松类幼林的抚育方式 ,1999年起我们选用了国内、外生产的新型林用除草剂 ,如 74.7%农民乐可溶性粒剂、70 %森草净可湿性粉剂、10 %草灌净水悬剂、6 .8%林草净水剂、75 %金锄可湿性粉剂等 6种 8个剂型 ,在湿地松、马尾松幼林中进行化学除草试验 ,优选出74.7%农民乐可溶性粒剂 ,每公顷商品量3 0 0 0～ 3 75 0g于杂草、灌木生长旺盛期作茎、叶处理 ,除草效果达 90 %以上 ,且对松类幼林安全 ,经济效益和社会效益显著     

不同施肥方式对设施红地球葡萄生长及品质的影响

在设施红地球葡萄施入油渣、钙肥、绿肥和氮磷钾混合肥等4种肥料后,测定了其生长进程和果实品质.结果表明:尿素15 g+磷酸二铵20 g+硫酸钾15 g的氮磷钾混合肥配方能最大幅度促进果粒生长,最高可提升9.83个百分点;施绿肥,最大可提升果粒增长83％;施入过多氮磷钾混合肥与油渣,会导致营养生长过旺而抑制了生殖生长,不利于葡萄果粒的膨大;不同施肥方式中,钙肥对葡萄果粒的硬度提升较其他施肥方式有显著差异;绿肥和油渣对葡萄含糖量的提升较其他施肥方式有显著差异,但不能施入过多,以5.0kg/株和0.5kg/株为宜,较不施肥状态下葡萄含糖量可增加36.9％.     

湿地松、马尾松幼林化学除草技术的研究

为了改变松类幼林的抚育方式,１９９９年起我们选用了国际、外生产的新型林用除草剂,如７４．７％农民乐可溶性粒剂、７０％森草净可湿性粉剂、１０％草灌净水悬剂、６．８％林草净水剂、７５％金锄可湿性粉剂等６种８个剂型,在湿地松、马尾松幼林中进行化学除草试验,优选出７４．７％农民乐可溶性粒线公顷商品量３０００～３７５０ｇ于杂草、灌木生长旺盛期作茎、叶处理,除草效果达９０％以上,且对松类幼林安全,经济效益和效益显著。     

核磁共振法测定高州油茶种仁含油率试验

探讨了种仁含水量、颗粒大小和样品量对核磁共振法测定高州油茶种仁含油率结果的影响,并与索氏抽提法进行比较,同时讨论了核磁共振法的测定精密度和稳定性.试验结果表明:种仁含水量、颗粒大小和样品量对高州油茶种仁含油率测定有一定影响,测定时样品需烘至质量恒定,如无特殊要求,样品不需粉碎,样品量范围为6～11 g;同一样品,核磁共振法测定高于索氏抽提法,但两种方法间的绝对偏差小于2％;核磁共振法的测定精密度和稳定性好,可用于高州油茶种仁含油率的快速测定.     

辣木叶粉片剂制备工艺研究

以辣木叶粉为主要原料,采用湿法制粒压片法制备片剂,通过预实验、单因素和正交试验,确定了辣木叶粉片剂主料和辅料用量分别为辣木叶粉96.3%,木糖醇2%、硬脂酸镁0.56%、微粉硅胶0.14%,再加入主料总重50%的浓度为2%PVP水溶液,此条件下可制得呈天然淡绿色,表面光洁,色泽均匀一致,有辣木清香味的片剂。经对辣木叶粉片剂进行质量检查,辣木叶粉片剂制备工艺稳定,质量可控。     

Growth of Phlebiopsis gigantea in wood of seven conifer species

Heterobasidion parviporum and Heterobasidion annosum are widely distributed root‐rot fungi that infect conifers throughout Europe. Infection of conifer stumps by spores of these pathogens can be controlled by treating fresh stumps with a competing non‐pathogenic fungus, Phlebiopsis gigantea. In this study, growth of three Latvian strains of P. gigantea and the biological control agent ‘Rotstop’ strain was evaluated in stem pieces of Norway spruce, Scots pine, lodgepole pine, Douglas‐fir, Weymouth pine, Siberian larch and Sitka spruce. The growth rates of one H. parviporum and one H. annosum isolate were also measured in the same stem pieces. The growth rate of P. gigantea varied greatly in wood of different conifer species. It was higher in the three pine species, lower in Norway spruce and lowest in Sitka spruce and Siberian larch, and in Douglas‐fir, this fungus did not grow. The largest area of wood occupied by P. gigantea was in lodgepole pine. Growth of Latvian isolates of P. gigantea in the wood of Pinus and Picea species was comparable to that of the Rotstop isolate. Consequently, stump treatment with local P. gigantea isolates should be recommended. However, our results suggest that Douglas‐fir stump treatment against Heterobasidion by P. gigantea may be ineffective and other stump treatment methods should be considered.     

Growth of Mixed Birch-Coniferous Stands in Relation to Pure Coniferous Stands at Similar Sites in South-eastern Norway

Mean age, mean and top heights and yield were studied in 20 mixed stands of birch ( Betula pubescens Ehrh. and B. pendula Roth) and Picea abies (L.) Karst. and nine mixed stands of birch and Pinus sylvestris L. in south-eastern Norway. Each mixed stand and the adjacent pure coniferous stand (control) were growing under the same site conditions and had not been commercially thinned. There were no significant differences in mean age at breast height or in top heights between birch and conifers in the mixed stands, while mean height was significantly higher for birch than for spruce. A growth index was calculated based on total volume and age at breast height. For the spruce sites the growth in young mixed stands (birch < 17 m) was superior to that of pure spruce, while the difference was insignificant in older stands. The growth index correlated positively with the ratio between generatively and vegetatively regenerated birch trees, and negatively with the age of the oldest species in the mixture and with site quality. For the pine sites there was no significant difference in the growth index between mixed birch-pine and pure pine stands. A mixture effect of birch on the volume yield of spruce or pine could not be demonstrated.     

Defoliation by the Needle-shortening Pine Gall Midge,Thecodiplosis brachyntera,on Pines in Central Sweden

An outbreak of the needle-shortening pine gall midge, Thecodiplosis brachyntera , occurred on Scots pine, Pinus sylvestris (L.) and lodgepole pine, P. contorta (Dougl.) in central Sweden during 1995-1998. The larval feeding of T. brachyntera kills current-year needles and heavy infestation causes severe defoliation. A pattern of fluctuating defoliation among years and sites was found on both pine species. Defoliation was evenly distributed in the crown of P. sylvestris during years of high as well as low infestation; apical whorls had as much defoliation as basal whorls. In P. contorta , however, there was a tendency for defoliation to be concentrated on branches in the most apical whorls. Growth ring increments on P. sylvestris with high levels of defoliation (71%) did not differ from trees with moderate levels (26%) of defoliation. Shoot lengths were significantly shorter, however, on heavily infested trees the year after defoliation.     

Boron in forest trees and forest ecosystems

This review critically examines the role of boron (B) in forests in view of recent findings on B nutrition and the continuing occurrence of B deficiency. Many perceptions about the role of B in plants and its uptake and mobility have been altered since the last review on B in forest trees in 1990. Now there is evidence for a fundamental role of B in the formation of the pectic structure in primary cell walls in plants, and further roles in membrane function are being explored. In plants, channel-mediated B uptake, active B uptake and B uptake by mycorrhizas have been shown, B transporters have been identified, and B retranslocation has been shown. We explore these findings and their consequences on forest trees and on ecosystems that they dominate. Particular emphasis is placed on B retranslocation and B in mycorrhizal symbiosis, given their importance in trees.     

Survival and Growth of Picea abies Regeneration after Shelterwood Removal with Single- and Double-grip Harvester Systems

Three stands in Sweden were followed for 7 yrs to study the survival and growth of Norway spruce [Picea abies (L.) Karst.] regeneration after shelterwood removal with single- and double-grip harvester systems. The height of all seedlings within circular plots was recorded before and after final cutting. The tallest seedling and one randomly selected seedling on each circular plot were permanently marked and their annual height growth was measured each year during the period 1993-1999. No significant differences between single- and double-grip harvester systems were found with respect to their effects on regeneration density, survival or annual height growth. The annual height growth of the individual seedlings after shelterwood removal was significantly correlated with seedling height before shelterwood removal. Significant differences were found in annual height growth between seedlings with high and low vitality. Logging damage did not affect the annual height growth. Several practical conclusions were drawn. First, the choice of harvester system does not affect seedling height growth or survival after shelterwood removal. Secondly, the removal of a 200 m³ shelterwood with 200 stems ha^-1 does not seem to constitute a serious problem for seedling survival and growth. Finally, estimated vitality and seedling height both seem to be fairly good predictors of postrelease survival and growth.     

Development of Pinus sylvestris Main Stems Following Three Different Precommercial Thinning Methods in a Mixed Stand

Reducing competition by point cleaning may be an attractive alternative to conventional precommercial thinning in forestry. In this study, survival and development of main stems of Scots pine (Pinus sylvestris L.) following point cleaning were examined in a mixed stand of mainly Scots pine and birch (Betula pendula Roth and Betula pubescens Ehrh.) in northern Sweden. Treatments studied were: no precommercial thinning, conventional precommercial thinning, point cleaning of all secondary stems, and point cleaning of only the secondary stems that were higher than the main stem, within a radius of 0.8 m from the main stem, respectively. A randomised complete block design with three replicates was used. Measurements taken 13 growing seasons after these treatments showed that conventional precommercial thinning was the best treatment for retaining Scots pines as main stems. However, conventional precommercial thinning resulted in the poorest timber quality of the remaining Scots pines in terms of stem taper, thickest branch diameter and relative live crown height. In conclusion, point cleaning has to be followed by a complementary cleaning operation if the objective is to retain Scots pines as main stems in such mixed stands.     

Tree planting for dryland salinity control in Australia

Dryland salinity is emerging as a major form of land and water degradation in southern Australia, particularly in Western Australia, South Australia and Victoria, and to a lesser extent in New South Wales, Tasmania and Queensland.Tree planting, in combination with other vegetation treatments, is regarded as a leading solution to dryland salinity. Research has now shown that planting trees can significantly lower groundwater tables, and thereby reverse the causal process of salinisation. Substantial progress has been made towards answering the basic questions of which species to grow, how to plant, where to plant, at what density and configuration to plant, and how much area to plant. The economic potential for commercial tree planting has given impetus to partial reforestation in higher rainfall (> 600 mm yr^–1) areas. Even so, serious constraints are apparent, relating primarily to cost, uncertainty and attitude. The future should bring increasing community input and control, technical refinement and gradual adoption, provided all aspects of the issue are well researched, relevant information is well communicated and programmes are well administered. Some specific requirements for future research are identified in this review.     

Effect of Cuttings on the Scenic Beauty of a Tree Stand

The opinions of 207 respondents on the visual effects of seven different cutting types were asked using a nine-point verbal scale ranging from ''worsens very much'' to ''improves very much''. Other estimates were obtained by letting the same respondents evaluate photographs of stands which had been treated with different cuttings. The direct questions gave results quite similar to the evaluations of photographs for all but young respondents, indicating that most respondents were able to imagine the effect of the treatment correctly. The results based on the evaluation of photographs indicated that the effect of regenerative cuttings is negative while the impact of thinnings is positive. After a few years of cutting the stand is already regarded as clearly more pleasant than immediately after the cutting. Natural regeneration with seed trees seems to be a way to avoid the very negative immediate impact of clear-felling, especially in the case of Scots pine. Women, young, urban people and those who do not own forest or have work related to forests tended to experience thinnings less positively and saw regenerative cuttings as more harmful than the other test groups did.     

Pinus contorta growth in northern Sweden as affected by soil scarification

The aim of this study was to quantify the effects of different soil scarification methods on tree growth. Soil scarification influenced stem volume and stem biomass yield of lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) in a 17-year-old field trial in boreal Sweden. Soil scarification (disc trenching, mounding and ploughing) resulted in an average stem volume yield of 3.1 and 34.2 m³ ha^–1 on the poor and intermediate sites, respectively, while corresponding values for no soil scarification were 0.9 and 16.7 m³ ha^–1. In comparison to no scarification, ploughing increased volume yields by 500% on the poor site and by 200% on the intermediate sites. The ranking according to stem volume yield was ploughing > disc trenching = mounding no soil scarification. Averaged over the two sites, the mean annual increment of stem biomass was 219% and 145% higher (in d.w., 0.26 kg and 0.34 kg per sample tree) after ploughing compared with no soil scarification, for the average and dominant sample trees, respectively. Although not significant, the increased growth rate after soil scarification decreased the average stem basic wood density of the sample trees with 1.6% and 5.3%, at the poor and intermediate sites, respectively. In conclusion, soil scarification significantly increased the 17-year stem volume yield compared with no scarification. The results also indicate that the difference in stem biomass yield between ploughing and the other methods, especially no soil scarification, will increase even more in the near future.