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131.
132.
Red mud was investigated in triglyceride transesterification with a view to determine its viability as a basic catalyst for use in biodiesel synthesis.The effect of calcination temperature on the structure and activity of red mud catalysts was investigated.It was found that highly active catalyst was obtained by simply drying red mud at 200°C.Utilization of red mud as a catalyst for biodiesel production not only provides a cost-effective and environmentally friendly way of recycling this solid red mud waste,significantly reducing its environmental effects,but also reduces the price of biodiesel to make biodiesel competitive with petroleum diesel. 相似文献
133.
赤潮灾害经济损失评估技术方法 总被引:3,自引:0,他引:3
为有效应对赤潮灾害防灾减灾、灾后救援及管理的需求,在综合分析前人提出的赤潮灾害损失评估技术方法的基础上,参考赤潮灾害对受灾体的危害特点,结合实际工作的需求及在实际中可获取的业务数据,提出了赤潮灾害经济损失评估指标体系;根据灾害经济学理论,借鉴其他自然灾害经济损失评估的先进思想,采用市场价格法,分别建立了包括海水养殖业经济损失、滨海旅游业经济损失、赤潮灾害业务与应急监测费用和赤潮灾害处置费用的赤潮灾害经济损失评估模型;最后,提出了赤潮灾害损失评估的技术流程。 相似文献
134.
丘陵红壤开发的水土资源保护及农业产业化经营模式 总被引:1,自引:1,他引:1
以湖南省桃源县为例,针对目前丘陵红壤开发存在的主要问题,在探明季节性干旱成因和发生规律、水资源合理调蓄利用依据的基础上,提出了红壤丘陵区抗御季节性干旱的水分管理对策和主要措施;通过不同经营模式的水土资源动态观测、分析,提出了红壤丘陵区土壤允许流失值应≤200 t·km-2·a-1、相应的降水径流系数<0.25 等水土资源协调发展的关键技术指标,并在丘陵红壤坡地上建立了土壤侵蚀模数<100 t·km-2·a-1 的“土壤-水分-生物”资源互利型的高效利用模式。同时,以市场为导向,优化产业结构为中心,应用上述研究成果,建立了茶叶、苎麻、果业、庭园高效生态农业等四大科技先导型的产业化规模经营体系,为我国红壤丘陵区的农业产业化开发提供实用模式与示范样板。 相似文献
135.
Changes in the survival parameters of the red fox were analyzed at different phases of the population cycle. It was found that the survival rate in all age classes, including newborns, drastically increased at the phase of population growth. The relationship between the general mortality rate and population size was determined. A hypothesis concerning the mechanism of these changes in the general mortality rate is suggested. 相似文献
136.
催化荧光法测定痕量亚硝酸根 总被引:12,自引:0,他引:12
本文研究了在稀磷酸介质中,亚硝酸根对溴酸钾氧化中笥红的反应,建立了催化荧光法测定痕量亚硝酸根的方法,实验表明,亚硝酸根在0.05-0.40μg.25ml^-1范围内与ΔF成线性关系,大多数常见的共存离子不影响其测定。本法用于水样中亚硝酸根的测定,结果比较满意。 相似文献
137.
Juan S. Vargas Soto Christopher Beirne Andrew Whitworth Juan Carlos Cruz Diaz Eleanor Flatt Ruthmery Pillco-Huarcaya Erik R. Olson Alejandro Azofeifa Guido Saborío-R Roberto Salom-Pérez Deiver Espinoza-Muñoz Leslie Hay Lawrence Whittaker Carmen Roldán Ricardo Bedoya-Arrieta Eben North Broadbent Péter K. Molnár 《Conservation biology》2022,36(2):e13813
Understanding how human modification of the landscape shapes vertebrate community composition is vital to understanding the current status and future trajectory of wildlife. Using a participatory approach, we deployed the largest camera-trap network in Mesoamerica to date to investigate how anthropogenic disturbance shapes the occupancy and co-occurrence of terrestrial vertebrate species in a tropical biodiversity hotspot: the Osa Peninsula, Costa Rica. We estimated species richness in different categories of land protection with rarefaction analysis and estimated the expected occupancy with a joint species distribution model that included covariates for anthropogenic disturbance, land protection, habitat quality, and habitat availability. Areas with the most stringent land-use protections (e.g., Corcovado National Park, 24 species [95% CI 23–25]) harbored significantly more species than unprotected areas (20 species [19.7–20.3]), mainly due to a reduced presence of large-bodied species of conservation concern in unprotected areas (e.g., jaguar Panthera onca and white-lipped peccary Tayassu pecari). Small-bodied generalist species, such as opossums (Didelphidae) and armadillos (Dasypus novemcinctus), in contrast, were more common at disturbed sites, resulting in a significant difference in vertebrate community composition between sites with low and high disturbance. Co-occurrence of species was also mainly associated with response to disturbance. Similar responses to disturbance create two groups of species, those whose site-level occupancy usually increased as anthropogenic disturbance increased and those whose estimated occupancy decreased. The absence of large-bodied species entails an important loss of ecological function in disturbed areas and can hinder forest development and maintenance. Efforts to protect and restore forested landscapes are likely having a positive effect on the abundance of some threatened species. These efforts, however, must be sustained and expanded to increase connectivity and ensure the long-term viability of the wildlife community. 相似文献
138.
徐州红色旅游资源开发探讨 总被引:5,自引:0,他引:5
市场调查与分析显示,红色旅游资源在徐州市旅游资源开发中占据重要地位。徐州红色旅游资源的开发必须坚持高标准与高质量建设、区域合作、政府投资和市场化运作相结合、旅游产品活化四大原则。在徐州红色旅游资源开发战略举措上,建议采取坚持打造精品、加大宣传促销力度和整合徐州文化旅游资源、适时建设“军事文化大观园”三大战略举措。 相似文献
139.
介体厌氧催化活性艳红K-2BP脱色及构效特性研究 总被引:3,自引:1,他引:3
研究了筛选出的4种结构相似的醌类氧化还原介体对活性艳红K-2BP厌氧脱色的促进作用,并分析了介体促进效果与其化学结构活性相关性. 在35℃中温厌氧条件下,采用间歇批量实验法,测定不同体系中介体催化活性艳红K-2BP脱色效果.结果表明,①结构相似的醌类氧化还原介体蒽醌(AQ)、1,5-二氯蒽醌(1,5-AQ)、1,8-二氯蒽醌(1,8-AQ)和1,4,5,8-四氯蒽醌(1,4,5,8-AQ),均促进活性艳红K-2BP脱色,反应速率提高了1.4~3倍;②当醌类介体投加浓度为4 mmol·L-1,活性艳红K-2BP染料浓度为300 mg·L-1时,促进作用由大到小的顺序为:1,8-AQ>1,5-AQ>AQ>1,4,5,8-AQ;③ 当活性艳红K-2BP染料浓度为300 mg·L-1时,1,8-AQ促进效果最佳且脱色速率常数随1,8-AQ浓度的增加而增加呈线性关系;④介体促进效果与介体取代基团数量、位置和电子共轭效应相关.本研究初步建立了氧化还原介体定性/定量构-效关系数学模型,探究和完善非水溶性氧化还原介体催化强化理论体系. 相似文献
140.
The adsorption behaviors of heavy metals onto novel low-cost adsorbent, red loess, were investigated. Red loess was characterized by X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectra. The results indicated that red loess mainly consisted of silicate, ferric and aluminum oxides. Solution pH, adsorbent dosage, initial metal concentration, contact time and temperature significantly influenced the efficiency of heavy metals removal. The adsorption reached equilibrium at 4 hr, and the experimental equilibrium data were fitted to Langmuir monolayer adsorption model. The adsorption of Cu(II) and Zn(II) onto red loess was endothermic, while the adsorption of Pb(II) was exothermic. The maximum adsorption capacities of red loess for Pb(II), Cu(II) and Zn(II) were estimated to be 113.6, 34.2 and 17.5 mg/g, respectively at 25°C and pH 6. The maximum removal efficiencies were 100% for Pb(II) at pH 7, 100% for Cu(II) at pH 8, and 80% for Zn(II) at pH 8. The used adsorbents were readily regenerated using dilute HC1 solution, indicating that red loess has a high reusability. All the above results demonstrated that red loess could be used as a possible alternative low-cost adsorbent for the removal of heavy metals from aqueous solution. 相似文献