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601.
602.
Recent Industrial Applications of Lignin: A Sustainable Alternative to Nonrenewable Materials 总被引:10,自引:0,他引:10
Lignin represents a vastly under-utilized natural polymer co-generated during papermaking and biomass fractionation. Different types of lignin exist, and these differ with regard to isolation protocol and plant resource (i.e., wood type or agricultural harvesting residue). The incorporation of lignin into polymeric systems has been demonstrated, and this depends on solubility and reactivity characteristics. Several industrial utilization examples are presented for sulfur-free, water-insoluble lignins. These include materials for automotive brakes, wood panel products, biodispersants, polyurethane foams, and epoxy resins for printed circuit boards. 相似文献
603.
Wolfgang Fennel Thomas Neumann 《Ambio-人类环境杂志》2001,30(4):232-236
海洋生态系统的动力问题,如可观测的化学-生物量的时空变化是由于生物和物理过程决定的.预报海洋系统的未来发展需要有一个理论框架.如模型,而这个模型是根据对相关的各个不同过程的研究和了解而发展的.从理论上描述海洋系统的自然方法似乎是把化学生物模型与环境模型结合在一起.但是,环境模型相对比较先进,而化学-生物过程的定量理论描述比较落后.本文讨论了一些关于发展相容理论的方法和问题,指出了海洋生物学模型和海洋学模型耦合的潜在盖处. 相似文献
604.
As CO2 emission trading in Europe has been established it is of essential importance to distinguish between biogenic and fossil emissions. Emissions resulting from bio-fuels and biogenous fractions are categorized as climate-neutral. Determination of plants using only fossil or bio-fuels is simple but categorization becomes more difficult for plants using a mix of fossil and bio-fuel such as solid recovered fuels. In the meantime, different methods for solving this problem have been developed. Using different approaches and technologies, all of these methods have the same goal: determining the biomass content (biogenic fraction), for example, in solid recovered fuels or in the off-gas of a mono- or co-incineration plant in order to calculate the biogenic carbon dioxide emissions. In the following article, the most common methods for determining the biogenic fraction of fuels, namely the Selective Dissolution Method, the Balance Method and the 14C-Method will be explained in detail. 相似文献
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The results of a discrete choice experiment (DCE) as a part of a survey among the urban riverbank residents on the Red River in Winnipeg, Manitoba, Canada, indicated that the risk of over-dike flooding, set at 2ft above the 1997 flood water level, was a significant determinant of both voluntary and mandatory evacuation, compared to those set at the 1996 or 1997 levels. Mandatory evacuation was more preferred over voluntary evacuation when the likelihood of flooding was at its most severe, and the opposite relationship was the case when the likelihood was low. The notification time for evacuation, suggested as 1, 2, and 4 days, proved to be an insignificant attribute, whereas the respondents indicated significant preference for full flood compensation over an offer of either 80% or 90% flood relief, irrespective of the alternatives of voluntary or mandatory evacuation. 相似文献
608.
Nicole Geberzahn Wolfgang Goymann Christina Muck Carel ten Cate 《Behavioral ecology and sociobiology》2009,64(2):193-204
Birdsong serves to attract mates and to deter territorial rivals. Even though song is not restricted to males, this dual function
has almost exclusively been demonstrated for male song. To test the generality of hypotheses on birdsong, we investigated
female song in the sex-role reversed, classically polyandrous African black coucal (Centropus grillii) in the context of female–female competition. We compared spontaneously vocalizing females with females vocally responding
to a playback simulating a conspecific intruder. Females changed vocal parameters in response to playbacks: They lowered the
pitch of their vocalizations and enhanced the duration of song elements when being challenged. Also, the composition of the
vocalizations was altered. There was no significant correlation between pitch and body size parameters in spontaneous song,
but there was for response songs, with larger females having a lower pitch. These changes in vocal properties suggest that
the vocalizations are important for mutual assessment of competitive abilities in females. Our findings confirm the general
role of intrasexual competition in vocal communication of birds. 相似文献
609.
Wolfgang H. Höll 《Environmental geochemistry and health》2010,32(4):287-290
In this review paper, various methods for arsenic removal from water have been described by explaining the related mechanisms
of each methods. Advantages and drawbacks were discussed. Membrane methods were suggested as reliable methods for elimination
of arsenic from water in addition to other conventional separation methods. 相似文献
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