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91.
The application of digital photogrammetry to measure distribution of tree positions with stereo image couple is introduced in detail, and the procedure of stereo vision applied in forestry environment is explored. Nonlinear error in measure model is adopted in the camera calibration; the interactive correlation matching is used under constraint of epipolar line and edge of tree detected by Canny operator. Results prove that application of digital photogrammetry technology to measure distribution of tree positions can meet demand of precision in experimental conditions.  相似文献   
92.
风对林木的影响   总被引:7,自引:0,他引:7  
风除对森林造成了危害外,还对树木的生长、形态以及森林生态等产生影响。随着全球气候变化的发展,更多和更强的暴风出现的危险性日益增加。为了更好地理解风害对树木、林分和森林生态系统的影响,为森林经营管理提供依据,本文对近10年来国际上有关风对林木影响内容进行归纳总结。结果表明,风对林木影响的研究主要在以下几个方面取得了重要的进展:1)风与林木的空气动力学关系;2)树木在风力荷载下其适应性的生长机理;3)树木对风的生理响应:4)森林风害的危险评估。所有这些研究大都在人工用材林中进行的。此外,本文还介绍了该研究领域需要开展的其它研究,如1)天然林或天然次生林的风害研究;2)风害形成的林窗和森林动态研究;3)风害对森林生态主要过程的影响研究;4).风害与森林管理研究。图3参61。  相似文献   
93.
随着大气CO2浓度的升高,主要由其引起的温室效应与对生物新陈代谢的影响变得越来越显著。森林生态系统在全球碳循环中扮演着重要的角色。为了评估和理解森林土壤CO2通量及其随空气和土壤温度的季节和昼夜变化规律,我们在长白山北坡典型阔叶红松林内利用静态箱技术进行了原位观测。实验在整个生长季(6月初至9月末)昼夜进行,利用气相色谱进行气体分析。结果表明: 长白山阔叶红松林土壤是大气二氧化碳源,其CO2通量具有明显的季节和昼夜变化规律。通量的变化范围是(0.30-2.42)μmol穖-2穝-1,平均值为0.98μmol穖-2穝-1。土壤CO2排放的季节规律表明,土壤CO2通量的变化与气温和土壤温度的变化有关。CO2平均通量的最大值出现在7月((1.27±23%)μmol穖-2穝-1),最小值出现在9月((0.5±28%)μmol穖-2穝-1)。土壤CO2的昼夜波动与土壤温度变化有关,而在时间上滞后于温度的变化。森林下垫面土壤CO2通量与土壤温度显著相关,与6cm深度土层温度相关系数最大。基于气温和土壤温度计算的Q10值范围为2.09-3.40。图2表3参37。  相似文献   
94.
The impacts of elevated atmospheric CO2 concentrations (500 μmol·mol−1 and 700 μmol·mol−1) on total soil respiration and the contribution of root respiration ofPinus koraiensis seedlings were investigated from May to October in 2003 at the Research Station of Changbai Mountain Forest Ecosystems, Chinese Academy of Sciences, Jilin Province, China. After four growing seasons in top-open chambers exposed to elevated CO2, the total soil respiration and roots respiration ofPinus koraiensis seedlings were measured by a Li-6400-09 soil CO2 flux chamber. Three PVC cylinders in each chamber were inserted about 30 cm into the soil instantaneously to terminate the supply of current photosynthates from the tree canopy to roots for separating the root respiration from total soil respiration. Soil respirations both inside and outside of the cylinders were measured on June 16, August 20 and October 8, respectively. The results indicated that: there was a marked diurnal change in air temperature and soil temperature at depth of 5 cm on June 16, the maximum of soil temperature at depth of 5 cm lagged behind that of air temperature, no differences in temperature between treatments were found (P>0.05). The total soil respiration and soil respiration with roots severed showed strong diurnal and seasonal patterns. There was marked difference in total soil respiration and soil respiration with roots severed between treatments (P<0.01); Mean total soil respiration and contribution of root under different treatments were 3.26, 4.78 and 1.47 μmol·m−2·s−1, 11.5%, 43.1% and 27.9% on June 16, August 20 and October 8, respectively. Foundation item: This study was supported by the Knowledge Innovation Project of the Chinese Academy of Sciences (KZCX1-SW-01) and the National Natural Science Foundation of China (30070158). Biography: LIU Ying (1976-), female, Ph. D. Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, P. R. China. Responsible editor: Song Funan  相似文献   
95.
Based on the results of the atmospheric deposition classification of the year 1989, a methodical approach should be introduced, which—based on the modelled total deposition rates—enables us to characterise the input situation of forest monitoring plots and to delimit load areas in Germany. In 1989, the deposition situation in nearly 1,800 forest monitoring sites (BZE/extensive Soil Condition Inventory) in Germany could be explained by four factors (or three, excluding sea salt impact) with the help of a factor analysis. The factor values were grouped into six deposition types with typical compounds and regional patterns. The classified input rates of the soil inventory plots adequately represent the stress situation and deposition changes in Germany. The application of the statistical approach on the level of Brandenburg clarifies the special local input situation. Due to the special combination of deposed elements, the sources of emissions can be characterised as well. When the soil inventory is repeated, a project planned for 2006, this approach can be used in order to determine homogenous areas for stratified data evaluation.  相似文献   
96.
从1999年8至10月,2000年的4至6月,2002年8月至2003年9月,在平均树高为26米的长白山阔叶红松林内,用红外气体分析仪(2250D,LI-CORInc.和LI-COR,820)测定了不同高度的二氧化碳浓度。根据测定的数据,分析了阔叶红松林二氧化碳廓线的日变化和季节变化动态。结果表明:CO2浓度的垂直分布在白天和夜间是不同的,在接近地面处CO2浓度始终最大。从季节CO2廓线看出,在植物生长季节林冠处CO2浓度有明显的成层现象,不同高度(60~2.5m)的CO2浓度3月份变化较小差值为10mmol穖ol-1,而在7月份变化较大,差值为60mmol穖ol-1。7月份林冠处(22,26,32m)CO2浓度梯度较大,浓度差为8mmol穖ol-1。计算位于涡度相关仪器之下的40米高空气柱中CO2贮存状况表明,年际贮存是负值,但对NEE的贡献很小。图4参11。  相似文献   
97.
[目的]探索葡萄糖酸亚铁固体脂质纳米粒的制备方法。[方法]采用两步W/O/W乳化方式制备葡萄糖酸亚铁固体脂质纳米粒(SLN)。以包埋率为指标,研究内外相、油水相体积比,卵磷脂浓度对SLN包埋率的影响。[结果]试验确定当内相中水相与油相的体积比为0.2,外水相与内相乳状液的体积比为5∶1,卵磷脂浓度为5%时,SLN的包埋率取得最大值,为52.48%。在内水相引入海藻酸钠(1∶2,W/W)的结果表明,SLN的包埋率增大,为59.03%,粒径、Zeta电位和多分散系数发生变化。体外释放试验表明,SLN能起到保护葡萄糖酸亚铁经受胃酸环境的作用,并在模拟肠液中表现为突释的释放效果。[结论]固体脂质纳米粒对葡萄糖酸亚铁有较好的保护及释放效果,可为无机铁补充剂的生产提供新的技术手段。  相似文献   
98.
Staphylococcus aureus and coagulase-negative staphylococci (CNS) isolated from bovine mastitis were examined for their ability to interact with 125I-labelled fibronectin, fibrinogen and type II collagen. Their relative surface hydrophobicity and production of extracellular capsule were also investigated. Almost all S. aureus strains bound fibronectin (mean value 23%), fibrinogen (mean value 12%) and type II collagen (mean value 16%). CNS bound fibronectin (mean value 6%) and type II collagen (mean value 7%), but not fibrinogen (mean value 2%). The specificity of binding of these proteins to S. aureus strain F1440 and to coagulase-negative Staphylococcus chromogenes strain BO52 was studied by adding an excess of unlabelled proteins. Fibronectin and collagen binding were observed to be specific, varying between 50 and 75%, whereas the specificity of fibrinogen binding to S. aureus strain F1440 was lower (26%). Most of the S. aureus strains (63%) showed very high surface hydrophobicity (autoaggregation) or lower hydrophobicity (29% of the strains) and the rest were hydrophilic. None of the CNS strains autoaggregated, 44% were classified as hydrophilic strains. Hydrophilic strains (except the reference strains) did not show extracellular capsule production. However, the encapsulated (reference) strains showed low binding to these proteins as compared to their unencapsulated variants. Pre-treatment of S. aureus strain F1440 and S. chromogenes strain BO52 with trypsin decreased their fibronectin binding capacity and surface hydrophobicity, whereas pre-treatment with bovine milk (except on collagen binding to strain F1440) did not significantly affect binding to these proteins. These data indicate that S. aureus and CNS isolated from bovine udder infection have the ability to bind to tissue matrix and plasma proteins which may be exposed in the traumatized or toxin-damaged udder epithelial lesions.  相似文献   
99.
Japanese farmers manage their irrigation water based on their past experiences and preferences, considering such factors as weather and available water (hereafter defined as empirical water management). They elaborately control the intake and drainage rates of their own paddy fields to maintain optimal ponding depths. But these well-managed systems will drastically change because of the decreasing number of farmers. Therefore, it is necessary to clarify if the optimal ponding depth will be maintained within the limits of traditionally-allowed water intake rate from the main river. The first objective of this study was the quantification of actual water use in the paddy fields, resulting from the farmers water management on the basis of their experience. The significance of the present water intake rate under empirical water management was studied for a paddy field command area of about 230 ha. Water intake rates and the water requirements of the whole area were investigated by measuring the flow rate at 17 points of irrigation and drainage canals. Characteristics of the farmers empirical water management were investigated by measuring the hourly changes in inflow and outflow rates for a sub-area using an automatic measurement system, and an inferential method of determining water management patterns for the paddy fields was proposed. The newly-proposed inferential method was introduced in the tank model, which expresses the characteristics of water management in the command area. The Shuffled Complex Evolution Algorithm (SCE-UA) method was used for optimizing the model parameters. It was proven that the model accuracy improved when the farmers empirical water management was taken into account. The optimal amount of water to be applied to the command area was quantified by the simulation. The second objective was to predict the effect of the decreasing number of farmers on future water use conditions. The simulated result indicates the difficulty of maintaining optimal ponding depth for the whole command area when the farmers empirical water management is not maintained. In other words, results indicated that efficient water use requires an automatic water management system or a new pipeline system to replace the farmers present empirical water management.  相似文献   
100.
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