Apparent quantum yield of photosynthesis of winter wheat and its response to temperature and intercellular CO2 concentration under low atmospheric pressure on Tibetan Plateau     

SHI Peili  ZHANG Xianzhou  ZHONG Zhiming 《中国科学D辑(英文版)》2005,48(Z1)

The Tibetan Plateau is characterized by lower atmospheric pressure, lower air temperature and high daily and seasonal variation due to high elevation. The photosynthesis of plants is significantly influenced by these alpine environmental factors. Apparent quantum yield (αA) is one of the basic parameters of photosynthesis and mass production. Its accuracy determination is of significance to model photosynthesis of C3 plants and global change on the plateau. In the Lhasa Plateau Ecological Station with 65.4 kPa of atmospheric pressure at an elevation of 3688 m, Li-Cor 6400 portable photosynthesis system was used to measure light response curves of winter wheat in different temperatures and intercellular CO2 concentration (Ci).The slope of light response curve in weak light area of PFD from 0 to 150 μmol m-2 S-1 was used to evaluate the value of αA. The dependence of αA on temperature and intercellular concentration was analyzed. In 30℃, the average value of αAWaS 0.0476 ± 0.0038. It is not quite different from the values in low elevation areas. αA is influenced both by temperature and by the ratio of CO2and O2 partial pressure ([CO2]/[O2]). The measured values in the previous study were much lower.This might be due to systematic errors from instrument and data processing methods. The values of αA decreased linearly with temperature. It decreased 0.0007 in every 1℃ increase of temperature. The decrease slope is similar to those of C3 plants in the previous researches. While [O2] is constant, αA increases with Ciwith a hyperbolic relationship. In comparison with low elevation areas, the αA on the Tibetan Plateau is more sensitive to increase of CO2.  相似文献   

量子共振检测仪在南极医学研究中的应用初探   总被引：1，自引：0，他引：1       下载免费PDF全文

恽君惕  朱广瑾  刘燕  谢琏湖  宋秀风 《极地研究》2002,14(1):57-61

本研究应用量子共振检测仪 (QRS)一种基于量子分析技术的灵敏能量分析器 ,测定了 1 0名南极考察队员的生理和心理改变。在出发前 (BD)、南极居留 6月时 (AR)和居留一年返回后次日 (RE)分别采取头发进行磁场分析。测定生理和心理指标 :三碘甲状腺胺酸 (T3)、四碘甲状腺胺酸 (T4)、促甲状腺激素 (TSH)、抑郁、孤独、不容忍、压力 ,评分以正负数值表示。结果表明 ,AR和RE各项指标的量化值与BD基础值相比都明显下降 (p <0 .0 1 )。例如 ,抑郁 (平均值±标准误 , X±S X)为 :1 .1 0± 0 .80 (BD) ,- 8.3± 0 .30 (AR) ,- 7.7± 0 .36(RE) ;TSH为 :- 2 .2± 0 .92 (BD) , 9.4± 0 .45(AR) ,- 8.4± 0 .40 (RE)。QRS量化值的负向改变反映了功能的异常 ,这一初步结果证实了文献报道的在南极长期居留可引起甲状腺活动改变和心境失调。  相似文献   

CCD蓝敏技术     

季凯帆 《天文研究与技术》1999,(3):11

Ｃ Ｃ Ｄ 用于天文领域已经有近２０ａ （ 年） 的历史, 随着 Ｃ Ｃ Ｄ 技术的发展, 作为重要参数之一的量子效率也得到极大提高, 已经有许多效率在蓝端超过９０ ％ 的芯片应用于天文观测。本文介绍了提高 Ｃ Ｃ Ｄ 蓝端量子效率的多种方法, 包括电极减薄、 Ｌｕｍｏｇｅｎ 镀膜、 Ｃ Ｃ Ｄ 减薄、紫外预照、电子预注入和增透膜等技术等等。可以看到, 采用 Ｃ Ｃ Ｄ 减薄、电荷注入和选择合适的增透膜可以使量子效率接近１００ ％  相似文献   

M2SiO4型矿物与炉渣性质的CNDO／2法研究     

尹周澜  邹祖荣 《矿物学报》1990,10(3):259-265

通过CNDO/2量子化学计算,得到了M_2SiO_4型矿物的结构特征。根据不同阳离子对硅氧四面体骨架的影响程度,对M_2SiO_4型矿物的类质同象现象、熔点、深成岩浆作用中的结晶次序,熔融状态的导电性及M_2SiO_4型炉渣的热力学性质作了系统研究。  相似文献   

Pyropia yezoensis can utilize CO2 in the air during moderate dehydration     

周伟  何林文  杨芳  林阿朋  张宝玉  牛建峰  王广策 《中国海洋湖沼学报》2014,32(2):358-364

Pyropia yezoensis,an intertidal seaweed,experiences regular dehydration and rehydration with the tides.In this study,the responses of P.yezoensis to dehydration and rehydration under high and low CO 2 concentrations((600–700)×10-6 and(40–80)×10-6,named Group I and Group II respectively)were investigated.The thalli of Group I had a signifi cantly higher effective photosystem II quantum yield than the thalli of Group II at 71% absolute water content(AWC).There was little difference between thalli morphology,total Rubisco activity and total protein content at 100% and 71% AWC,which might be the basis for the normal performance of photosynthesis during moderate dehydration.A higher effective photosystem I quantum yield was observed in the thalli subjected to a low CO 2 concentration during moderate dehydration,which might be caused by the enhancement of cyclic electron fl ow.These results suggested that P.yezoensis can directly utilize CO 2 in ambient air during moderate dehydration.  相似文献   

沸石基质中CdS团簇的Raman光谱及量子尺寸效应     

王安平  于洪林  姚杰 《吉林大学学报(地球科学版)》2004,34(1):158-160

采用具有不同孔隙尺寸的沸石为基质约束CdS团簇的大小.通过测定Raman光谱观察到随着CdS团簇尺寸减小,Raman光谱中LO声子振动频率略向低频方向移动.利用二级LO声子的振动强度与一级LO声子的振动强度之比(2LO/LO),研究团簇电-声子耦合强弱的结果表明,随着团簇尺寸减小,电-声子耦合增强.  相似文献   

Quantum reflection as the reflection of subwaves     

袁文  殷澄  王贤平  曹庄琪 《海洋学报(英文版)》2010,29(9)

This paper studies quantum reflection with recent research on reflection coefficient. Based on the analytical transfer matrix method, a novel explanation for this phenomenon is proposed that quantum reflection is the reflection of subwaves, which originate inherently from the inhomogeneity of the fields and is always neglected in the semiclassical regime. Comparison with exact formula and the numerical calculations for different potentials has confirmed the reliability and the validity of the proposed theory.  相似文献   

二维GaAs 基光子晶体微腔的制作与光谱特性分析     

彭银生  叶小玲  徐波  牛洁斌  贾锐  王占国  梁松  杨晓红 《海洋学报》2010,32(10):7073-7077

研究了以InAs量子点为有源区的二维GaAs基光子晶体微腔的设计与制作,测试并分析了室温下微腔的光谱特性.观察到了波长约为1137 nm,谱线半高宽度约为1 nm的尖锐低阶谐振模式发光峰.我们比较了不同刻蚀条件下光子晶体微腔的发光谱线,结果表明空气孔洞截面的垂直度是影响光子晶体微腔发光特性的重要因素之一.通过调节干法刻蚀工艺,改变空气孔半径与晶格常数的比率,可以在较大范围内调节谐振模式发光峰位置,达到谐振模式与量子点发光峰调谐的目的.  相似文献   

Concurrence, tangle and fully entangled fraction     

李明  费少明  李先清 《海洋学报(英文版)》2010,29(9)

We show that although we cannot distil a singlet from many pairs of bound entangled states, the concurrence and the tangle of two entangled quantum states are always strictly larger than those of one of them, even both entangled quantum states are bound entangled. We present a relation between the concurrence and the fidelity of optimal teleportation. We also give new upper and lower bounds for concurrence and tangle.  相似文献   

Entanglement of two atoms interacting with a dissipative coherent cavity field without rotating wave approximation     

康国栋  方卯发  欧阳锡城  邓小娟 《海洋学报(英文版)》2010,29(11)

Considering two identical two-level atoms interacting with a single-model dissipative coherent cavity field without rotating wave approximation, we explore the entanglement dynamics of the two atoms prepared in different states using concurrence. Interestingly, our results show that the entanglement between the two atoms that initially disentangled will come up to a large constant rapidly, and then keeps steady in the following time or always has its maximum when prepared in some special Bell states. The model considered in this study is a good candidate for quantum information processing especially for quantum computation as steady high-degree atomic entanglement resource obtained in dissipative cavity.  相似文献