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101.
在从化石燃料向可再生能源转变以及避免气候变化失控的竞赛中,风能已经大大领先于太阳能和地热能.世界各地太阳能电池板发电能力为70,000兆瓦,地热发电能力约11,000兆瓦.当前全球约有80个国家有风电场,总发电容量近24万兆瓦,中国和美国都处于领先地位.
在过去的十年中,世界风力发电能力每年增长近30%,其增长既是自身的特点所驱动,也是政策支持的扩张.风是丰富、无碳、永不枯竭的资源.它不耗水、不用燃油、用地少且容易大规模开发,可以快速联网,没有其他能源可与风能具有的优势相匹敌. 相似文献
102.
103.
环境监测是由于环境的污染而产生形成的,并伴随着环境保护事业的发展而不断前进。环境监测作为环境保护工作的要点.也是其环境决策的最重要依据.其水平高低的强弱反映了环境管理能力。离开了环境监测就等于失去了环境管理的奠基石。因此,为了加强环境保护,提高其环境管理的效率,我们必须依靠其环境监测。因此本文从多个方面阐述了如何提高环境监测的能力。 相似文献
104.
研究了UV/H2O2/草酸高铁铵体系下孔雀绿(Malachite green,MG)光降解过程中的影响因素,包括MG的初始浓度、初始pH值、投加H2O2浓度和草酸高铁铵浓度等。结果表明:MG初始浓度越低光降解越快,碱性条件有利于MG的降解,其最佳降解pH为11.0;随H2O2浓度的增加,MG降解率先增加后减少,在100mmol/L时,降解率最高;MG降解率随草酸高铁铵浓度增加而增加,于10.0mmol/L时MG降解率最高;UV/H2O2/草酸高铁铵体系的降解效果较强,交叉实验结果表明H2O2:草酸高铁铵浓度比在1~20:1时降解率均高于。因此该体系具有快速、简单、经济并高效率等特点,可应用于染料废水的降解和脱色工艺中。 相似文献
105.
Settlement decisions in blue tits: difference in the use of social information according to age and individual success 总被引:1,自引:0,他引:1
Dispersers are expected to assess breeding habitat quality before settlement. Although cues reflecting habitat quality are
well studied, social cues have not been as well evaluated. In this paper, we studied breeding habitat selection during 3 years
in a natural population of blue tits, Cyanistes caeruleus, breeding in nest-boxes. Our aim was to investigate if this species used conspecific density and/or reproductive success
of con- and heterospecifics (i.e., social cues) in settlement decisions. The patterns observed were consistent with the idea
that juveniles, when dispersing from their natal patches, did not react to any of the cues that we tested. In contrast, breeders
that dispersed seemed to respond to both conspecific mean patch reproductive success (PRS) and breeding density of the settlement
patch in the year of dispersal, their response differing according to their own reproductive success. Indeed, failed breeders
moved to areas with high PRS and low density relative to source patches, while successful breeders behaved the opposite. The
comparison between juveniles and adults might be modulated by the limited time available to juveniles to gather information
on PRS and density at the end of the dispersing year. Adults lacking these time constraints, however, seemed to rely on these
conspecific cues although limited by their own quality. Additionally, breeders were more likely to be immigrants in patches
with relatively low breeding success and density the previous year, suggesting that settlement is influenced by multiple cues,
which may reveal information on different aspects of habitat and be available at different moments. Collectively, our results
support the importance of social cues for blue tits’ settlement. 相似文献
106.
The fate of Norse farming settlements in southwest Greenland has often been seen as one of the great mysteries of North Atlantic colonization and expansion. Preservation of organic remains in the permafrost of the area of the Western Settlement, inland from the modern capital Nuuk, allowed very detailed study of the phases of occupation. Samples were taken from house floors and middens during the process of archaeological excavations and from insect remains were abstracted and identified in the laboratory. In this study, we present a new paleoecological approach principally examining the fossil fly faunas from house floors. The results of our study provide contrasting detailed pictures of the demise of two neighboring farms, Gården under Sandet and Nipaatsoq, one where abandonment appears as part of a normal process of site selection and desertion, and the other where the end was more traumatic. The level of detail, which was obtained by analysis of the dipterous (true fly) remains, exceeds all previous work and provides insights otherwise unobtainable. 相似文献
107.
Kumar V Rani S Malik S Trivedi AK Schwabl I Helm B Gwinner E 《Die Naturwissenschaften》2007,94(8):693-696
Daytime light intensity can affect the photoperiodic regulation of the reproductive cycle in birds. The actual way by which
light intensity information is transduced is, however, unknown. We postulate that transduction of the light intensity information
is mediated by changes in the pattern of melatonin secretion. This study, therefore, investigated the effects of high and
low daytime light intensities on the daily melatonin rhythm of Afro-tropical stonechats (Saxicola torquata axillaris) in which seasonal changes in daytime light intensity act as a zeitgeber of the circannual rhythms controlling annual reproduction
and molt. Stonechats were subjected to light conditions simulated as closely as possible to native conditions near the equator.
Photoperiod was held constant at 12.25 h of light and 11.75 h of darkness per day. At intervals of 2.5 to 3.5 weeks, daytime
light intensity was changed from bright (12,000 lux at one and 2,000 lux at the other perch) to dim (1,600 lux at one and
250 lux at the other perch) and back to the original bright light. Daily plasma melatonin profiles showed that they were linked
with changes in daytime light intensity: Nighttime peak and total nocturnal levels were altered when transitions between light
conditions were made, and these changes were significant when light intensity was changed from dim to bright. We suggest that
daytime light intensity could affect seasonal timing via changes in melatonin profiles.
Professor Dr. E. Gwinner died on 07 September 2004. 相似文献
108.
109.
INTRODUCTION: This study evaluated the implementation of a second phase training program for novice drivers in Spain, which puts the primary focus of the training on the higher hierarchical levels of driver behavior. METHOD: Two hundred and sixty-three participants took part throughout the study, which was implemented as an experimental design with the test and control groups assessed before and after the one day safety training. Measurement of the impact of the training program focused on the participants' self-evaluation and self-reporting of some driving behavior indicators related to accident risk. RESULTS: Data analysis showed a change in the expected direction in the scale related to the skills for careful driving, but not for the other four scales considered. A feedback survey about the training course offered some important input for evaluating the organization, contents, tuition, and results of the three parts of the training program (discussion group, on-road and track training) as reported by the participants in the test group. CONCLUSIONS AND SUGGESTIONS: The results of the experiment show that using a one day driver safety course, it is possible to change some of the drivers' evaluations connected to safe driving style into safe direction. The follow-up period was exceptionally long (9 months) and the design (randomly divided experimental and control groups with before and after measurements) was reliable. More effort should be devoted to improving the on-road part of the training, which was often perceived as a typical driving lesson rather than a feedback drive. IMPACT ON INDUSTRY: The findings suggest consideration of a mandatory 2nd phase driver training programme as a means to raise awareness of the full range of risks encountered by novice drivers, and as already introduced in 5 EU countries: Austria, Estonia, Finland, Luxembourg and Switzerland. 相似文献
110.
A new mass estimate for the dodo (Raphus cucullatus), based on the lengths of the femur, tibiotarsus and tarsometatarsus, is attempted. The obtained mean mass is 10.2 kg, which
is less than previous estimates based on other methods, which ranged from 10.6 to 21.1 kg, and much lower than the 50 lbs
reported by a seventeenth-century eyewitness. The new estimated mass, which is similar to that of a large wild turkey, seems
more realistic than previous ones and supports the hypothesis that contemporary illustrations of extremely fat dodos were
either exaggerations, or based on overfed specimens. Pictures of “fat” dodos may also have been based on individuals exhibiting
a display behaviour with puffed out feathers. 相似文献