988 resultados para 312.27
Resumo:
土壤微生物(Soil microbes)是生态系统的重要组成部分,它参与土壤中复杂有机物质的分解和再合成,也参与C、N、S、P等的循环。土壤酶(Soil enzyme)是土壤中具有生物活性的蛋白质,它与微生物一起推动着土壤的生物化学过程,并在树木营养物质的转化中起着重要的作用。鉴于土壤微生物和土壤酶对环境变化的敏感性,它们在CO2浓度和温度升高时的反应将在很大程度上影响森林生态系统的结构和功能。因此,要全面评价大气CO2浓度和温度升高对整个生态系统的影响,有必要对CO2浓度和温度升高条件下的土壤微生物的反应进行深入的研究与探讨。本文应用自控、封闭、独立的生长室系统,研究了川西亚高山岷江冷杉(Abies faxoniana)根际、非根际土壤微生物数量,红桦(Betula albosinensis)根际微生物数量以及根际、非根际土壤酶活性对大气CO2浓度(环境CO2浓度+350±25μmol·mol-1,EC)和温度(环境温度+2.0±0.5℃,ET)升高及两者同时升高(ECT)的响应。结果表明: 1) EC和ET显著增加岷江冷杉根际微生物数量,但不同微生物种类对EC和ET的反应有所差异。6、8和10月,岷江冷杉根际微生物数量与对照(CK)相比,EC处理的根际细菌数量分别增加了35%、164%和312%,ET处理增加了30%、115%和209%;EC和ET处理对根际放线菌和根际真菌数量影响不显著。ECT处理的根际放线菌数量分别增加了49%、50%和96%,根际真菌数量增加了151%、57%和48%;而ECT对根际细菌数量影响不显著。EC、ET和ECT处理对岷江冷杉土壤微生物总数的根际效应明显,其R/S值分别为1.93、1.37和1.46(CK的R/S值为0.81)。 2) 红桦根际微生物数量对EC、ET和ECT的响应不同。生长季节(5~10月),高密度的红桦根际细菌数量与CK 相比,EC的根际细菌数量分别增加28%、33%、423%、65%、43%和79%,而低密度的红桦根际细菌数量增加不显著。ET能显著增加根际细菌数量(7~10月),其中高密度的根际细菌数量分别增加了377%、107%、35%、22%,而低密度的根际细菌数量分别增加了27%、27%、64%、48%;ECT对两个密度水平下根际细菌数量均未产生有显著的影响。高、低密度的红桦根际放线菌和根际真菌数量与 CK 相比,EC显著增加了低密度的红桦根际放线菌数量,而对高密度的根际放线菌数量无显著影响;ET和ECT对高低密度的红桦根际放线菌数量均未产生显著影响。EC和ET对高低密度的根际真菌数量也无显著影响,而ECT却显著增加了高低密度的根际真菌数量。 3) EC、ET和ECT处理的低密度红桦根际微生物(细菌、放线菌和真菌)数量没有显著高于或低于高密度根际微生物数量,表明短期内密度对红桦根际微生物数量不产生影响。 4) 不同种类的氧化还原酶对EC、ET和ECT的响应不同。5~10月,EC的红桦根际过氧化氢酶活性是CK 的1.44、1.06、1.11、1.10、1.12和1.24倍,差异显著(6月除外);ET和ECT处理根际过氧化氢酶活性无显著增加。EC的红桦根际多酚氧化酶活性比CK显著增加;ET的根际多酚氧化酶活性显著高于CK(8月除外)。ECT的根际多酚氧化酶活性高于CK,差异不显著。EC的根际脱氢酶活性分别增加了46%、40%、133%、48%、17%和26%,差异显著。5~7月,ET和ECT的根际脱氢酶活性高于CK的脱氢酶活性,而8~9月则相反,差异性均不显著。 5) EC、ET和ECT对不同种类的水解酶的影响不同。EC能显著增加红桦根际脲酶活性,5~10月分别增加了29%、42%,、70%、67%、59%和57%。ET和ECT 对根际脲酶活性未产生显著影响。EC显著提高根际转化酶活性,5、6和9月EC的根际转化酶活性分别比CK高51%、42%和40%。5和10月,ET的根际转化酶活性低于CK,而其余月份却高于CK,但均具有显著性差异。ECT的根际转化酶活性与CK的根际转化酶活性有显著性差异(9月除外),5、6和7月的根际转化酶活性分别提高了94%、198%和67%。 6) 与CK相比,EC、ET和ECT的非根际土壤微生物数量以及非根际土壤酶活性均无显著提高。EC、ET和ECT的过氧化氢酶、脲酶的根际效应明显,而多酚氧化酶和脱氢酶根际效应不明显。EC和ECT的转化酶根际效应明显,而ET的转化酶根际效应不明显。 It is well known that atmospheric CO2 concentration and temperature are increasing as a consequence of human activities. In past decades, considerable efforts had been put into investigating the effects of climate change on processes of forest ecological system. In general, studies had been mainly focused on the effects of elevated atmospheric CO2 on plant physiology and development, litter quality, and soil microorganisms. Studies showed that there was variation in the responses of root development and below-ground processes to climate between different plant communities. Since the concentration of CO2 in soil was much higher (10~50 times) than in the atmosphere, increasing levels of atmospheric CO2 may not directly in fluence below ground processes. Betula albosinensis and Abies faxoniana, as the dominated tree species of subalpine dark coniferous forest in the western Sichuan province, which play an important role in the structure and function of this kind of forest ecosystem. In our study, effects of elevated atmospheric CO2 concentration (350±25μmol·mol-1), increased temperature (2.0±0.5℃) and both of the two on the number of rhizospheric microbe and rhizospheric enzyme activity were studied by the independent and enclosed-top chamber’ system under high-frigid conditions. Responses of rhizospheric bacteria, actinomycetes and fungi number of Betula albosinensis and Abies faxoniana under different densities(high density with 84 stems·m-2, low density with 28 stems·m-2 ), and rhizospheric enzyme activity of Betula albo-sinensis to elevated CO2 concentration and increased temperature were analyzed and discussed. The results are as the following, 1) In comparion with the control, the numbers of rhizospheric bacteria of Abies faxoniana were increased by 35%, 164% and 312% significantly in June, August and October respectively of EC, and were increased by 30%, 115% and 209% respectively of ET.However the effect of EC and ET on rhizospheric actinomycetes and fungi was not significant. The number of rhizospheric actinomycetes of ECT were increased significantly by 49%, 50% and 96% respectively, and the increment of rhizospheric fungi were 151%, 57% and 48% respectively .The effect of ECT on rhizospheric bacteria was not significant. Rhizospheric effect of soil microbe for all treatments was significant, with the R/S of 1.93, 1.27 and 1.46 for EC, ET and ECT, respectively. 2) Treatment EC improved the number of rhizospheric bacteria of Betula albosinensis under high density significantly in comparison with the control, over the growing season, the greatest increment of rhizospheric bacteria was from July. However, EC had no effect on the number of rhizospheric bacteria under low density. Except May and June, treatment ET improved the number of rhizospheric signifcantly. The effect of treatment ECT on the number of rhizospheric bacteria under different densities was not significant. Of treatment EC, the number of rhizospheric actinomycetes of Betula albosinensis under low density were increased significantly, however, treatment EC did not stimulate the number of rhizospheric actinomycetes under high density. Simultaneously, treatment ET and ECT did not stimulate the number of rhizospheric actinomycetes. Finally, in treatment ECT, the number of rhizospheric fungi under high density were increased significantly, however treatment EC and ET did not stimulate the number of rhizospheric fungi under different densities. 3) Of treatment EC, ET and ECT, the number of rhizospheric microbe of Betula albosinensis under low density were not more or fewer than that of microbe under hign density along the growing season, which showed that plant density had no effect on the nmber of microbe. 4) From May to October, 2004,rhizospheric catalase activity of Betula albosinensis of treatment EC was 1.44, 1.06, 1.11, 1.10, 1.12 and 1.24 times as treatment CK respectively, and the difference was statistically significant(except June). Treatment ET and ECT did not increase rhizospheric catalase activity significantly. In treatment EC, the rhizospheric pohyphenol oxidase activity was higher than treatment CK significantly. The rhizospheric pohyphenol oxidase activity of treatment ET was higher than CK significantly (except August). The rhizospheric pohyphenol oxidase activity of treatment ECT was higher than CK, but the difference was not statistically significant. Over the growing period, the rhizospheric dehydrogenase activity were increased 46%, 40%, 133%, 48%, 17% and 26% respectively by treatment EC, and the difference was statistically significant. From May to July, the rhizospheric dehydrogenase activity in treatment ET and ECT was higher than CK, but from August to October, the rhizospheric dehydrogenase activity was lower than CK, the difference was not significant. 5) Treatment EC increased rhizospheric urease activity significantly, from May to October, rhizospheric urease activity were increased 29%, 42%, 70%, 67%, 59% and 57% respectively by EC. Treatment ET and ECT had no effect on rhizospheric urease activity. Treatment EC improved rhizospheric invertase activity significantly, in May, June and September, the rhizospheric invertase activity of treatment EC were increased 51%, 42% and 40% in comparison with the control. Except May and October, the rhizospheric invertase activity of treatment ET was markly higher than CK. The rhizospheric invertase activity of treatment ECT was significantly different from CK (except September), in May, June and July treatment ECT increased rhizospheric invertase activity by 94%, 198% and 67% respectively. 6) In comparison with the control, treatment EC, ET, and ECT had no effect on the number of non-rhizospheric microbe and non-rhizospheric enzyme activity. Rhizospheric effect of catalase and urease for all treatments was significant, but rhizospheric effect of pohyphenol oxidase and dehydrogenase was not significant. Rhizospheric effect of invertase of EC and ECT was significant, but rhizospheric effect of invertase of ET was not significant.
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在中国原子能科学研究院的HI-13串列静电加速器上完成了19F+27Al耗散反应产物的激发函数测量。束流19F的入射能量从110.25MeV到118.75MeV,步长250keV,测量了实验室系+57°,+31°,-15°和-29°出射的类弹产物B,C,N,O,F和Ne的激发函数。观测到激发函数具有耗散反应的特征涨落结构,分析了激发函数之间的长程角度关联以及强烈的电荷数关联。
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利用高能离子研究了110keV的He+注入Al2O3单晶及随后230MeV的208Pb27+辐照并在不同温度条件下退火样品的光致发光的特性.从测试结果可以清楚地看到在375nm,390nm,413nm和450nm出现了强烈的发光峰.经过600K退火2h后测试结果显示,390nm发光峰增强剧烈,而别的发光峰显示不明显.在900K退火条件下,390nm的发光峰开始减弱相反在510nm出现了较强的发光峰,到1100K退火完毕后390nm的发光峰完全消失,而510nm的发光峰相对增强.从辐照样品的FTIR谱中看到,波数在460—510cm-1间的吸收是振动模式,经过离子辐照后,吸收带展宽,随着辐照量的增大,Al2O3振动吸收峰消失,说明Al2O3振动模式被完全破坏.1000—1300cm-1之间为Al-O-Al桥氧的伸缩振动模式,辐照后吸收带向高波数方向移动.退火后的FTIR谱变化不大.
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测量了19F+27Al耗散反应产物B,C,N,O,F和Ne的激发函数,入射束流的能量从110.25MeV 到118.75MeV,能量步长为250keV.从产物的能量自关联函数中提取了反应中所形成的中间双核系统的转动惯量,与相粘模型计算的刚体转动惯量相比较,结果表明形成的双核系统有大的形变.
Resumo:
在中国原子能科学研究院的HI-13串列静电加速器上完成了114MeV和118.75MeV的19F+27Al 耗散反应产物B,C,N,O,F,Ne,Na和Mg的微分截面测量.条形27Al同位素靶的大小尺寸为 10mm×50mm,平均厚度约67μg/cm2.固定入射束流19F的能量,通过移动靶位,先后轰击了靶上20个不同的位置.实验结果表明,在弹靶系统、入射能量以及探测系统都相同的多次独立的微分截面测量中,截面的涨落不呈现高斯型几率分布.截面测量的这种不重复现象难以用有限计数率的统计性质来解释.
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测量了19F+27Al耗散反应产物B,C,N,O,F和Ne的激发函数,入射束流的能量从110.25MeV 到118.75MeV,能量步长为250keV.用能量自关联函数方法从激发函数中提取了各反应产物的平均衰变宽度,利用同时考虑反应中所形成的中间双核系统的转动特性和衰变特性而发展了的Ericson核反应统计理论,讨论了19F+27Al耗散反应中双核系统随时间的演化过程.
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主要研究了110keV的He~+高温注入Al_2O_3单晶及1.1MeV/u的~(208)Pb~(27+)辐照注氦Al_2O_3样品的光致发光的特性。从测试结果可以清楚地看到在375nm,413nm和450nm处出现了强烈的发光峰。并且在600K,5×10~(16) ions/cm~2剂量点,样品的发光峰是最强的。这表明He~+注入Al_2O_3后使带隙中深的辐射中心复合的效率大幅度提高,极大的增强了其发光强度,而且发光伴随着蓝移现象。而经过高能~(208)Pb~(27+)辐照后的样品,在390nm出现了新的发光峰,从FTIR谱中我们能够看到,可能是~(208)Pb~(27+)辐照相对沉积膜出现一定的晶化,其中含有许多纳米尺寸的Al_2O_3晶粒所致。
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完成了114MeV19F+27Al深部非弹性碰撞产物的角分布测量.分析了反应产物B,C,N,O,F,Ne,Na,Mg和Al的实验室系角分布,讨论了反应形成的中间双核系统随时间演化过程中角分布所表现出的耗散特点.从实验上提取了反应产物各元素的角分散参数并作了角分散参数的理论拟合,讨论了角分散参数的物理意义以及角分散参数与耗散反应产物的电荷数Z之间的依赖关系.