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本文对用硫法锂渣制取白炭黑的基本原理及工艺流程作了较为详细的阐述,对该工艺的各种影响因素进行了探讨,并制得了合格的白炭黑,为锂渣的综合利用开辟了新的途径。 相似文献
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陕晋蒙三角区自然环境面临的主要灾害及对策 总被引:1,自引:0,他引:1
陕晋蒙三角区是我国未来一个新能源基地,在全国具有重要的地位。本文从该区的特点出发,论述了自然环境的主要灾害及成因,进而提出了减灾的相应措施与建议。 相似文献
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Edward M. Sykes Tabitha M. Innocent Ido Pen David M. Shuker Stuart A. West 《Behavioral ecology and sociobiology》2007,61(11):1751-1758
Sex allocation theory offers excellent opportunities for testing how animals adjust their behaviour in response to environmental
conditions. A major focus has been on instances of local mate competition (LMC), where female-biased broods are produced to
maximise mating opportunities for sons. However, the predictions of LMC theory can be altered if there is both local competition
for resources during development and an asymmetry between the competitive abilities of the sexes, as has been seen in animals
ranging from wasps to birds. In this paper, we test the extent to which asymmetric larval competition alters the predictions
of LMC theory in the parasitoid wasp Nasonia vitripennis. We found that the body size of both sexes was negatively correlated with the number of offspring developing within the host.
Further, we found that when faced with high levels of competition, the body size of females, but not males, was influenced
by the sex ratio of the competing offspring; females were smaller when a higher proportion of the brood was female. This asymmetric
competition should favour less biased sex ratios than are predicted by standard LMC theory. We then develop a theoretical
model that can be parameterised with our data, allowing us to determine the quantitative consequences of the observed level
of asymmetric larval competition for sex allocation. We found that although asymmetric competition selects for less biased
sex ratios, this effect is negligible compared to LMC. Furthermore, a similar conclusion is reached when we re-analyse existing
data from another parasitoid species where asymmetric larval competition has been observed; Bracon hebetor. Consequently, we suspect that asymmetric larval competition will have its greatest influence on sex ratio evolution in species
that have smaller clutches and where local mate competition is not an issue, such as birds and mammals. 相似文献
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Marieke C. Verweij Ivan Nagelkerken Suzanne L. J. Wartenbergh Ido R. Pen Gerard van der Velde 《Marine Biology》2006,149(6):1291-1299
Caribbean seagrass beds are important feeding habitats for so-called nocturnally active zoobenthivorous fish, but the extent to which these fishes use mangroves and seagrass beds as feeding habitats during daytime remains unclear. We hypothesised three feeding strategies: (1) fishes feed opportunistically in mangroves or seagrass beds throughout the day and feed predominantly in seagrass beds during night-time; (2) fishes start feeding in mangroves or seagrass beds during daytime just prior to nocturnal feeding in seagrass beds; (3) after nocturnal feeding in seagrass beds, fishes complete feeding in mangroves or seagrass beds during the morning. We studied the effect of habitat type, fish size, social mode and time of day on resting and feeding behaviour of large juvenile (5–10 cm) and sub-adult (10–15 cm) Haemulon flavolineatum in mangroves and seagrass beds during daytime. Sub-adults occurred in mangroves only, spent most time on resting, and showed rare opportunistic feeding events (concordant with strategy 1), regardless of their social mode (solitary or schooling). In contrast, large juveniles were present in both habitat types and solitary fishes mainly foraged, while schooling fishes mainly rested. Exceptions were small juveniles (±5 cm) in seagrass beds which foraged intensively while schooling. Large juveniles showed more feeding activity in seagrass beds than in mangroves. In both habitat types, they showed benthic feeding, whereas pelagic feeding was observed almost exclusively in the seagrass beds. In both habitat types, their feeding activity was highest during 8:00–10:30 hours (concordant with strategy 3), and for seagrass fishes, it was also high during 17:30–18:30 hours (concordant with strategy 2). The study shows that both mangroves and seagrass beds provide daytime feeding habitats for some life-stages of H. flavolineatum, which is generally considered a nocturnal feeder. 相似文献
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人口是人口,资源与环境系统中最根本的主导因素,人口增长过快,将直接加大对资源与环境的压力,并影响人口素质的提高,根据我国人口庞大的基数,过快的增长速度,独特的人口结构和较低的文化素质现状,对生态环境造成的压力进行了系统分析,进而提出了控制人口增长,改善生态环境和全面发展国发经济的对策,以保证跨世纪人口,资源,环境呈现协调,持续,健康的发展趋势。 相似文献
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曲面效应法优化辅酶Q10发酵条件 总被引:1,自引:0,他引:1
以根癌土壤杆菌(Agrobacterium tum efaciens)1.1416的突变株AGR 0610为出发菌株,采用P lackett-Burm an设计法(P lackett-Burm an design,P-B)对影响AGR 0610发酵产辅酶Q10的相关因素进行了研究,选取到4种有显著效应的因素:糖蜜、大豆蛋白胨、玉米浆和蛋氨酸.再采用响应曲面法(response surface m ethodology,RSM)对这4种因素的最佳水平范围进一步探讨,得到二次回归方程,优化了培养基组成.当这4种因素分别取值为1.02%、0.49%、0.29%和0.34%时,辅酶Q10产量有最大预测值38.88 mg/L,并被实验所证实.图6表4参8 相似文献
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为探讨曹妃甸近岸海区表层沉积物粒度和粘土矿物组成和分布特征,利用激光粒度仪和X-射线衍射(XRD)分析的方法对曹妃甸近岸海区15个表层沉积物样品进行分析。结果表明:曹妃甸近岸海区沉积物以粉砂为主(45.2%),其次是砂(30.2%)和粘土(24.6%);研究区内四种粘土矿物含量依次为伊利石(55.8%)蒙皂石(24.9%)绿泥石(9.9%)高岭石(6.7%)。研究表明曹妃甸近岸表层沉积物含量和分布特征受物源、水动力等自然因素和围填海工程等人为因素共同影响;其中,围填海工程的长期实施对研究区表层沉积物中较细颗粒(粉砂和粘土)的分布影响较为明显;伊利石、高岭石和绿泥石分布特征与围填海导致的水动力改变密切相关。研究结果对曹妃甸近岸海区的沉积特征及沉积物物源、了解围填海工程对海洋沉积环境的影响有着一定的科学意义。 相似文献