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蟹、鱼网围混养对草型湖泊氮磷平衡的影响 总被引:8,自引:4,他引:4
研究了草型湖泊(东太湖)蟹、鱼网围混养对水域中氮、磷平衡的影响对养殖过程 中氮、磷的输入输出测算表明:利用该养殖模式进行生产,不仅不会加重水域中的氮、磷负荷量,相 反还可以从水域环境中吸收一部分氮、磷在整个养殖过程中,由于投放蟹、鱼种和饲料形成的氮、磷输入分别为27.889kg·hm~(-2)‘和4.381kg·hm~(-2),而起捕蟹、鱼导致的氮、磷输出分别为41.177kg·hm~(-2)‘和5.801kg·hm~(-2),可以从湖泊中吸氮、磷量分别为13.288kg·hm~(-2)‘和1.420kg·hm~(-2)该养殖 模式还具有理想的经济效益,对水生生物群落的影响亦较小,符合可持续发展的要求 相似文献
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Ge湖氮,磷平衡研究 总被引:2,自引:3,他引:2
Ge湖位于江苏省常州市西南13km处,水面面积164km^2,平均水深1.26m,是太湖湖洋的重要组成部分。其氮、磷平衡研究结果表明:①入湖氮、磷总量分别为4120.29t/a和270.03t/a;其中以河道入湖量最大,分别占入湖总量的71.9%和57.1%,其次是养殖投饵,分别占入湖总量的12.4%和29.9%;氮、磷的滞留系数分别为0.36和0.35,年滞留量分别为1481.6t和94.82t 相似文献
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绍兴鉴湖水域环境功能区区划 总被引:47,自引:6,他引:41
研究了25C条件上太湖北部湖区水-沉积界面的物质交换.结果表明:五里湖沉积物中的氮,磷和CODmn的释放程度明显高于梅梁湖,其NH4+-N、DTP和DCOD的平均溶出速率分别人158.2,2.05和27.8mg/(m2.d);梅梁湖北部湖区形态氮处于“负释放”状态,DTP和DCOD溶出速率分别为0.584mg/(m2.d)和8.9mg/(m2.d),此外,形态氮,磷和DCODR的水-沉积物界面物质交换量与底泥中氮,总 相似文献
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按照地球膨胀学说进行全球构造动力物理模拟的相似性研究,得到了膨胀地球岩石层弹性球壳力学模型的方程分析相似准则和地幔物质沿膨胀裂谷通道上涌流动的方程分析相似准则.按照各相似准则的约束,计算得到了满足与膨胀地球原型相似的模型参数:膨胀初始半径为0.46m;原始岩石层的厚度、密度分别为3×10-3m和(1.2-1.8)×10kg/m3,其强度为104Pa;原始地球膨胀内压为4.25×104Pa;原始地表重力为-1.25×10-2N/kg;上涌物质密度、粘度分别为1.2×102kg/m3和2×102Pa·s;原始地幔物质上涌厚度、速度和加速度分别为2.5×10-2m,2.0×10-3m/s和3×102m/s2.由此表明材料物性等条件能够较好地满足原型要求的模型条件. 相似文献
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好氧和厌氧条件对霞浦湖沉积物-水界面氮磷交换的影响 总被引:59,自引:4,他引:55
在实验室控制条件下,研究了日本霞浦湾和湖心区底泥中形态氮磷,在好氧和厌氧条件下水土界面交换量变化及差异,结果表明;好氧条件下,NO^-3-N,NO^-2-N,NH^+4,-N,和PO^3-4-P均有释放作用产生,量值多数较小,DTN和DTP则净释放作用接近零;厌氧条件下,NO^-3-N和NO^-2-N呈负释放状态,NH^+4-N和PO^3-4-P的释放速率是好氧条件下的2-8倍。 相似文献
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本文将迄今的新中国地震应急工作划分为4个发展阶段。本着“厚今薄古”并面向未来发展以古鉴今的指导思想,对地震应急事业发展进行了较为系统地回顾。对于各个阶段中若干重要的应急工作事件或者发展成就,作者做了适当的评述。 相似文献
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自1970年四川大邑6.2级地震后,我省开展了水化城震预报的探索。经过20多年的实践和研究,积累了大量的水化观测资料和几十闪中强以上地震的成功与失败的预报经验和教训。水化地震预报思路经过了单个异常对应及预报地震、中多项异常对应及预报地震和“八五”攻关的从异常群体的演变过程提取前兆信息对应及预报地震几个阶段。本文简要回顾了水化地震预报思路的发展过程,列举了各阶段水化异常对应及预报地震的典型震例。针对 相似文献
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Ulrich A. Corti 《Aquatic Sciences - Research Across Boundaries》1950,12(2):288-299
Summary The growth of body and organs and the chemical composition, concerning water-, ash-, fat-, amino acid- and total nitrogen
content, have been investigated of eggs and postembryonic development phases of rainbow trouts,Salmo irideus. The fry was hatched artificially and nourished exclusively with fresh beef liver.
Mitteilung aus der Eidg. Anstalt für Wasserversorgung, Abwasserreinigung und Gew?sserschutz an der Eidg. Technischen Hochschule, Zürich
Mitteilung siche diese Zeitschrift,12, 105–108 (1950). 相似文献
Mitteilung aus der Eidg. Anstalt für Wasserversorgung, Abwasserreinigung und Gew?sserschutz an der Eidg. Technischen Hochschule, Zürich
Mitteilung siche diese Zeitschrift,12, 105–108 (1950). 相似文献
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The widely exposed Chinese Neogene terrestrial deposits provide the best circumstance for the establishment of an accurate chronostratigraphic system of Eurasia, and the rapidly evolved mammalian fossils contribute efficiently to the division and correlation of Asian Neogene strata. A uniform Neogene biostratigraphic framework for China has already been established,with seven mammalian ages named. With a developed stratigraphic basis for the geochronologic "ages", seven chronostratigraphic "stage" have been established for the Chinese Neogene terrestrial strata, namely the Miocene Xiejian, Shanwangian,Tunggurian, Bahean, and Baodean stages, and the Pliocene Gaozhuangian and Mazegouan stages. Based on a series of research achievements, refined biostratigraphic, paleomagnetic and isotopic methods were combined and applied to continuous sections,and a Chinese Neogene chronostratigraphic sequence with accurate geological ages was established and improved in recent years. The lower boundaries of most of the stages could be correlated with those of the marine stages in the International Chronostratigraphic Chart, except the Tunggurian Stage, which is correlated with the European land mammal age. The biostratigraphic markers of the Chinese Neogene stages are usually first appearance of a single taxon, some representing regional species replacement, others indicating intercontinental migration of certain taxa. Candidate stratotype sections have been proposed for all the Chinese Neogene stages according to the principle and rule of modern stratigraphy, and other Chinese Neogene strata in different regions are comprehensively correlated. 相似文献
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位于四川省甘孜藏族自治州康定市内大渡河干流的长河坝-黄金坪水电站,为大渡河流域开发中,以长河坝、大岗山、瀑布沟等形成主要梯级格局开发方案中,"三库22级"水电站中的第10和11级电站,其地震监测台网也采用梯级设计方式,长河坝-黄金坪上下游水库地震监测台网统一设计、建设及监测,共享同一地震监测能力。通过对监测设备的技术指标、台基地噪声水平和震级-频度对数关系的分析,结果表明,长河坝-黄金坪水库区域地震固定台站建成后,地震监测能力达到并优于设计的理论监测能力,地震监测震级达到下限为ML 0.5的设计要求。 相似文献
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The effects of DDT on the regeneration of cutaneous wounds has been studied in Mystus (mystus) vittatus. The fishes were locally collected, they were inflicted incised wounds surgically and kept in 0.01 and 0.15 ppm concentrations of DDT. The regenerating skin at different stages of development ranging from 15 min to 25 d after the injury was studied through microtomy sections. The following toxic effects were studied:
- A small amount of DDT accumulated in the subcutis at the 25 days stage,
- the regeneration of wounds under DDT stress has been slower, delayed or irregular,
- the secretion of fibrinous exudate has been copious,
- epithelization and fibroblastic activities have been slower,
- the higher concentration of 0.15 ppm of DDT produced more toxic effects than the lower concentration of 0.01 ppm,
- the earlier stages of wound healing up to 3 d have been more adversely affected than later stages.