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311.
Nanocrystals were prepared by acid hydrolysis of bacterial cellulose microfibrils. These were topochemically trimethylsilylated, in an attempt to reduce their hydrophilicity. Composites were made by dispersing either native or silylated crystals in cellulose acetatebutyrate matrixes and solution casting of the dispersions. Particles were characterized by transmission electron microscopy. The composites were characterized by differential scanning calorimetry and dynamic mechanical analysis. The unmodified cellulose crystals exhibited better reinforcement characteristics than the trimethylsilated crystals. 相似文献
312.
Most ecological generalizations stem from the study of common organisms, but most species are rare. There are a number of reasons to expect that rare and common species may differ consistently in their characteristics, with possible implications for conservation. Past analyses of this issue, however, have generally considered only a single measure of rarity and have not corrected analyses for the lack of independence in the traits of related species. We compared several reproductive characteristics of Mediterranean annual crucifers as a function of their global range, regional abundance, and local population density in Israel, making use of independent contrast methods to correct for the phylogenetic relationships of the species involved. We found plants growing at low local density to be disproportionately likely to be self-compatible. Petal length and floral depth (sepal length) were correlated with breeding system but showed significant interaction effects between breeding system and abundance. Floral longevity was inversely related to abundance and also showed significant interaction effects between breeding system and abundance. Overall, rare species tended to display more extreme values for floral traits than did common plants with the same breeding systems; they had unusually large and deep flowers if self-incompatible and unusually small, shallow ones if self-compatible. 相似文献
313.
Two recent projects involving soils remediation at Superfund sites in southern New Jersey and northeastern Pennsylvania exemplify the power of “real time” field analytical support in reducing time and expense during a project's remedial phase. The remediation efforts at both of these CERCLA sites were supported by ERM-FAST on-site analytical facilities which, in a “real-time” scenario, achieved all data quality objectives (DQOs), met all regulatory agency requirements, and satisfied the client's needs. Both of these sites offer illustrations of the effectiveness of field analysis for vastly differing site contaminants. The client benefited from substantial savings on analytical cost as well as the savings realized through efficient and effective process and schedule management. 相似文献
314.
The reduction of SO2, HCl, and NO(x) concentrations using calcium magnesium acetate (CMA) as a novel sorbent in a simulated municipal waste incinerator flue gas was investigated. The reduction of individual SO2, HCl, and NO(x) concentrations was tested at 850 degrees C and it was found that CMA could reduce the SO2 concentration by 74%, HCl concentration by 64%, or NO(x) concentration by 94%. It was observed that individual SO2 or HCl capture increased with increasing initial oxygen concentration in the reacting gas or increasing sorbent input. NO(x) reduction decreased with increasing initial oxygen concentration in the reacting gas. The simultaneous reduction of SO2, HCl, and NO(x) concentrations by CMA was also investigated. It was found that CMA could simultaneously capture 60% SO2 and 61% HCl and reduce NO(x) concentrations by 26%, when the initial oxygen concentration in the reacting gas was 4%. During the simultaneous reduction of SO2, HCl, and NO(x), it was noted that as the initial oxygen concentration in the reacting gas increased, the efficiency of SO2 capture increased too, but the efficiency of HCl capture and the efficiency of NO(x) destruction decreased. 相似文献
315.
Ortho-substituted, non-planar PCBs reduce dopamine content in both nonhuman primate brain and pheochromocytoma (PC12) cells. Planar, dioxin-like, congeners have no effect on dopamine content in PC12 cells. Additional in-vitro results indicate that dopamine reduction by PCBs is due to inhibition of tyrosine hydroxylase activity. 相似文献
316.
Shengguo Xue Yuzhen Ye Feng Zhu Qiongli Wang Jun Jiang William Hartley 《环境科学学报(英文版)》2019,78(4):276-286
Bauxite residue is a highly alkaline byproduct which is routinely discarded at residue disposal areas. Improving soil formation process to revegetate the special degraded lands is a promising strategy for sustainable management of the refining industry. A laboratory incubation experiment was used to evaluate the effects of gypsum and vermicompost on stable aggregate formation of bauxite residue. Aggregate size distribution was quantified by fractal theory, whilst residue microstructure was determined by scanning electron microscopy and synchrotron-based X-ray micro-computed tomography. Amendments addition increased the content of macro-aggregates( 250 μm) and enhanced aggregate stability of bauxite residue. Following gypsum and vermicompost addition, fractal dimension decreased from 2.84 to 2.77, which indicated a more homogeneous distribution of aggregate particles. Images from scanning electron microscopy and three-dimensional microstructure demonstrated that amendments stimulate the formation of improved structure in residue aggregates. Pore parameters including porosity, pore throat surface area, path length, and path tortuosity increased under amendment additions. Changes in aggregate size distribution and microstructure of bauxite residue indicated that additions of gypsum and vermicompost were beneficial to physical condition of bauxite residue which may enhance the ease of vegetation. 相似文献
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318.
William McDonough Michael Braungart 《生态毒理学报》2004,(3):13-16
从摇篮到摇篮设计是一种建筑学的生态智能设计理念,它涉及到完全健康的、可恢复的居住区的材料、建筑物和模式的相关产业.与从摇篮到坟墓体系不同,从摇篮到摇篮设计把人类系统看作是营养循环系统,其中的每一种物质都能够支撑生命.作为生物养分设计的材料在使用后为大自然提供了营养物;通过生产-恢复-再造的产业闭路系统技术养分得以循环.依据选择安全、健康因素的科学建议,从摇篮到摇篮设计把对材料的利用发挥到了极致.本着对自然、文化、气候负责的精神,在工业化国家和发展中国家,它推出的建筑物与社区规划都创造了多种多样的经济、社会和生态价值. 相似文献
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