智能交通系统研究综述

分析了智能交通系统研究的知识经济背景和发展历程，并提出我国智能交通系统的研究方向和发展对策。     

Towards the sustainable intensification of agriculture—a systems approach to policy formulation

The sustainable intensification of agriculture involves providing sufficient food and other ecosystem services without going beyond the limits of the earth’s system. Here a project management approach is suggested to help guide agricultural policy to deliver these objectives. The first step is to agree measurable outcomes, integrating formal policy goals with the often much less formal and much more diverse goals of individual farmers. The second step is to assess current performance. Ideally, this will involve the use of farm-scale metrics that can feed into process models that address social and environmental domains as well as production issues that can be benchmarked and upscaled to landscape and country. Some policy goals can be delivered by supporting ad hoc interventions, while others require the redesign of the farming system. A pipeline of research, knowledge and capacity building is needed to ensure the continuous increase in farm performance. System models can help prioritise policy interventions. Formal optimization of land use is only appropriate if the policy goals are clear, and the constraints understood. In practice, the best approach may depend on the scale of action that is required, and on the amount of resource and infrastructure available to generate, implement and manage policy.     

地方性知识与民族地区生态的可持续发展

指出了地方性知识由于其独特的作用在民族地区生态的可持续发展方面扮演着重要角色,是解决民族地区生态与发展问题的手段之一。通过对民族地区地方性知识在生态保护上的独特优势进行分析,提出了挖掘地方性知识,发挥其生态保护作用的措施。     

水分和热胁迫处理对4种针叶树苗木气体交换和水分利用效率的影响

以杉木、马尾松、花旗松和北美乔柏为研究对象 ,研究了水分和热胁迫对生长期间苗木的气体交换、瞬间水分利用效率和稳定碳同位素组成 (δ1 3C值 )等生理生态指标的影响 ,结果如下 :(1 )水分胁迫使杉木、马尾松、花旗松和北美乔柏 4个树种的净光合速率显著下降。但热胁迫只影响杉木和北美乔柏的净光合速率 ,对马尾松的净光合速率影响不大。 (2 )对针叶气孔导度的研究发现 ,水分和热胁迫均对马尾松苗木针叶气孔导度有显著影响 ,但对杉木和北美乔柏苗木针叶的气孔导度只有轻微影响。 (3)水分和热胁迫处理对马尾松苗木的瞬间水分利用效率有显著影响 ,但对杉木和北美乔柏的瞬间水分利用效率无显著影响。 (4 )水分胁迫处理对杉木、马尾松、花旗松和北美乔柏 4个树种的稳定碳同位素组成 (δ1 3C值 )均有显著影响 ,随着水分胁迫程度的加深 ,4个树种苗木针叶的δ1 3C值增大 (负值绝对值变小 ) ,说明其永久水分利用效率更高。 (5 )热胁迫对杉木和北美乔柏苗木针叶的δ1 3C值有显著影响 ,且在热胁迫下 ,两树种苗木针叶的δ1 3C值减小 (负值绝对值增大 ) ,即永久水分利用效率下降。但热胁迫对马尾松和花旗松苗木的δ1 3C值没有显著影响     

干旱对6种野生花卉光合色素含量与气体交换的影响

为给野生耐旱花卉在城市绿化中的应用提供理论依据,在温室内用盆栽法测定了燕山地区6种野生耐旱花卉苗木干旱胁迫进程中的对照、干旱胁迫5d、暂时萎蔫和永久萎蔫4点的光合色素含量与气体交换变化。结果表明:在土壤干旱进程的对照、干旱5d、暂时萎蔫和永久萎蔫各时间的总叶绿素、类胡萝卜素和叶绿素a与叶绿素b比值,除栓翅卫矛、孩儿拳头和木半夏各自的总叶绿素含量没有明显差别外,其余各自的总叶绿素含量、类胡萝卜素含量和叶绿素a与叶绿素b比值等指标的差异均显著或极显著;随土壤含水量降低,6种苗木蒸腾速率、净光合速率和气孔导度总体呈下降趋势,在永久萎蔫点三项指标降低幅度排序:蒸腾速率为木半夏>蚂蚱腿子>南蛇藤>孩儿拳头>叶底珠>栓翅卫矛;净光合速率为孩儿拳头>叶底珠>蚂蚱腿子>南蛇藤>木半夏>栓翅卫矛;气孔导度为蚂蚱腿子>叶底珠>孩儿拳头>南蛇藤>木半夏>栓翅卫矛;不同苗木的光合色素含量和三个指标对干旱胁迫的反应不同预示各苗木具有不同适应干旱的机理。     

Response of gas exchange rates in <Emphasis Type="Italic">Abies firma</Emphasis> seedlings to various additional stresses under chronic acid fog stress

In order to clarify the chronic influence of acid fog on the gas exchange rates of momi fir (Abies firma Sieb. et Zucc.) trees, we exposed them to simulated acid fog (pH 3) for 3 years. The composition of the acid fog was similar to that observed in a region where momi fir trees have been declining, and it contained organic acids. We then treated the firs with various additional stresses, such as drought, low temperature, fine root cutting, ozone exposure, soil acidification, nitrogen load, and rhizosphere aluminum stress. Under chronic exposure to acid fog, the momi fir seedlings exhibited a pattern of stomatal behavior whereby they excessively opened in summer and closed in winter. Furthermore, the stomata of these seedlings tended to open during drought stress, and their needles were visibly injured after ozone exposure. The net photosynthesis rates of the seedlings exposed to acid fog were regulated by their stomatal aperture, rather than directly by acid fog. These results suggest that acid fog exposure disturbs the control of stomatal function in the momi fir seedlings. In addition, we found that chronic acid fog exposure suppressed the decrease in net photosynthesis rate, due to its nitrogen load.     

A Study on Water Exchange in Root Zone of ProtectiveForest Ecosystem in Loess Area

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Assessment of sugar maple tree growth in relation to the partitioning of elements in xylem along a soil acidity gradient

Partitioning of elements in tree xylem is being increasingly studied, as it suggests that elements are potentially mobile within the xylem long after their uptake. A recent study revealed that only the most mobile xylem fraction (water-soluble) of base cations (calcium [Ca], magnesium [Mg], and potassium [K]) increased at higher soil acidity, while the two mobile fractions (water- and acid-soluble) of acidic metals—potentially phytotoxic aluminium (Al), cadmium (Cd) and manganese (Mn)—were significantly enhanced on very acid soils. The current paper presents an investigation of soil-wood chemistry relationships with basal area tree growth. It was hypothesized that the growth of sugar maple would be reduced by low base cation and high acidic metal concentrations in the xylem mobile fractions. Sugar maple trees (n = 55) from six watersheds in southern Quebec, Canada were analysed by sequential chemical extractions for the water-soluble, acid-soluble and residual fractions of base cations (Ca, K, Mg) and acidic metals (Al, Cd, Mn) in xylem. Generally, tree growth was positively correlated to concentrations of base cations in wood (ρ = 0.27-0.50) and soil (ρ = 0.41-0.67), and negatively correlated to concentrations of acidic metals in wood (ρ = −0.33 to −0.52) and soil (ρ = −0.67). However, these relations differed depending on the element fraction considered. Water- and acid-soluble xylem concentrations of base cations and Al were among the best predictors of growth trends (R² = 0.46-0.51). The relationship between acidic metals and tree growth is further discussed.     

用离子交换树脂催化法合成松油醇

探讨了用离子交换树脂催化合成松油醇的工艺条件,考察了溶剂、反应温度和反应时间等对水合反应的影响。     

常规干燥室余热回收装置的研究

分析研究具有强制集中换气木材干燥室的余热回收装置,并对其节能效果进行测试分析。对不同干燥阶段测试结果表明,从干燥室排出的通过余热回收装置后温度下降了13～16.3℃,补充到干燥室中的新鲜空气通过余热回收装置温度可以升高9～11.9℃。此余热回收装置的热回收效率为18.6%～28%,平均效率为22%,理论计算常规干燥每1m3、47mm厚的水曲柳的总排湿能量为1.4×106kJ,用该装置可节省热能为2.88×105kJ,相当于节省标准煤9.84kg。