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Kolchugina Tatyana P. Vinson Ted S. 《Mitigation and Adaptation Strategies for Global Change》1996,1(2):197-218
Several management practices are available to conserve and sequester C in the agricultural sector of the former Soviet Union (FSU). The highest rate of C accumulation would result from the implementation of a no-till management option which will only continue during the first ten years until new C equilibrium is reached. Agroforestry management options provide a longer period for C accumulation, but at a lower rate. It is possible that the longest period of C conservation may be achieved by increasing the area under perennial grasses in the crop rotation. During the first decade of implementation of the management practices, the amount of C conserved or sequestered would be approximately equal to the current rate of net C sequestration in FSU forest sector. At present, agricultural soils and vegetation of the FSU store approximately 120 Pg C; the accumulation of soil organic matter is 0.032 Pg C yr-1. The annual C loss in the FSU agricultural sector was estimated at 0.21 Pg C yr-1. 相似文献
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循环经济与上海可持续发展 总被引:16,自引:1,他引:16
介绍了近年来循环经济在德国等国家的崛起,勾勒了循环经济的基本理论和行原则,指出循环经济该成为上海实施可持发展战略的突破口提出了上海发展循环经济的必然性,目标,领域和行动举措。 相似文献
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利用镜下实测法和线性规划法统计了云南镇沅金矿区煌斑岩中矿物的实际含量。据此划分出该区煌斑岩岩石类型;总结出蚀变煌斑岩和矿化煌斑岩的过程中选岩矿物的变化规律;结合质量平衡计算,探讨了煌斑岩蚀交流体和矿化流体的性质。 相似文献
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详细研究了祁连—柴达木盆地北缘地区石炭系泥岩的微量元素和稀土元素地球化学特征。各微量元素在各剖面及不同层位变化相当复杂 ,但仍有一定规律 ,这种变化与其物源供应和沉积成岩环境有关。各样品稀土总量变化较大 ,以甘肃永昌煤山子剖面总量最高 ;各泥岩样品轻稀土富集 ,Eu负异常 ,δEu介于 0 .4 4~0 .90之间。微量、稀土元素组合及比值的变化 ,显示物源区母岩为花岗岩和玄武岩的混合 ,稀土分布模式显示源岩为粘土岩、花岗岩和中性岩的混合 ,两者示物源一致。元素的丰度及其比值 ,反映当时水介质环境大部分为海相 ,亦有部分为陆相 ,与其它相标志所表征的结果是一致的。 相似文献
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V. Sivakumar V. Ravi Verma P.G. Rao G. Swaminathan 《Journal of Cleaner Production》2007,15(18):1813-1818
Focus on eco-friendly processing techniques makes vegetable tanning a viable option in leather processing and establishes the subsequent need for the more efficient methods of extraction in tannin manufacture. Application of ultrasound has been tried in the extraction of tannins from myrobalan nuts in order to improve the extraction efficiency, to perform the extraction under milder process conditions and to reduce the process time. The influence of process parameters such as ultrasonic output power, time and temperature has been studied. Scale-up trials and the use of ultrasound in pulse mode have also been attempted. The results show that a three- to fivefold improvement is possible with ultrasonic output from 20 to 100 W. Extraction efficiency has been calculated from the maximum extractable materials from myrobalan nuts. Extraction efficiency is found to be 90% for ultrasound, 100 W without external heating as compared to 77% for control process at 70 °C for 4 h. Therefore, ultrasound could be employed even dispensing with provision for temperature controls. The use of ultrasound in pulse mode offered 70% extraction efficiency of continuous mode. Scale-up trials indicate that there exists an optimum ultrasonic output power depending on the amount of nuts used, to achieve better extraction efficiency. The effectiveness of ultrasonically extracted tannin solution has also been tested in the tanning process for its applicability. The degree of tanning efficacy has been assessed by shrinkage temperature measurement. The results indicate that ultrasonically extracted tannin solution is suitable for tanning process. Therefore, application of ultrasound in tannin extract manufacture is a viable option with added advantages. 相似文献
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