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231.
Jiao Demao Li Xia Huang Xueqing Chi Wei Kuang Tingyun Ku S. B. Maurice 《科学通报(英文版)》2001,46(13):1080-1084
With PEPC, PPDK, NADP-ME and PEPC+ PPDK transgenic and untransformed rice (Orysa sativa L.), the activities of related C4 photosynthesis enzymes, the chlorophyll fluorescence parameters, CO2 exchange and other physiological indexes were compared, in which the physiological characteristics of PEPC transgenic rice were mainly studied. The results were as follows: (ⅰ) The activities of PEPC in PEPC transgenic rice were 20-fold higher than those in untransformed rice; the light-saturation photosynthetic rates and the carboxylation efficiency of PEPC transgenic rice were increased by 55% and 50% more than those of untransformed rice, respectively, while the CO2 compensation point decreased by 27%. (ⅱ) The PSⅡ photochemical efficiency (Fv/Fm) and photochemical quenching (qP) of transgenic PEPC rice decreased less in comparison with those of untransformed rice after the treatment with high light intensity (3 h) or methyl viologen (MV), a photooxidative reagent, which demonstrated that the tolerance of PEPC transgenic rice to photoinhibition and photooxidation was enhanced. (ⅲ) Under the condition of high light intensity, the activity of RuBPCase in PEPC transgenic rice did not obviously vary while the activity induced of carbonic anhydrase (CA) in PEPC transgenic rice increased by 1.8 fold. These results would provide some beneficial enlightment for revealing the mechanism of high photosynthetic efficiency and breeding with high photosynthetic efficiency in rice. 相似文献
232.
本文在对赣方言区普通话水平测试成绩调查的基础上,分析了赣方言区考生常见的语音偏误,以及各等级的偏误特点,指出了调查分析结果对赣方言区普通话水平测试和普通话教学的积极作用。 相似文献
233.
Hezhong Li Haibo Kuang 《系统科学与信息学报》2009,7(1):65-76
In this paper, a model for multi-period bank hedging with interest rate futures is set up. Formulas for the optimal dynamic multi-period bank and static bank hedge ratio are derived. The described model offers the potential benefits of: (1) although these formulas are developed for the case of direct sheet balance multi-period hedging, the framework used is sufficiently flexible so that these formulas can be applied to bank loan or deposit multi-period hedging situations respectively. (2) Periodic modification and updating of the interest rate futures position, as suggested by interest rates, throughout the bank hedging horizons. (3) This paper examines a situation in which the return of loan, the interest rate of deposit and the equity capital of bank, and interest rate futures prices are cointergrated, Multi-period bank hedging formulas are derived under three-dimensional stochastic volatility model. However, empirical research is required for validating this model. 相似文献
234.
Global stability of endemic equilibrium point of basic virus infection model with application to HBV infection 总被引:1,自引:0,他引:1
In this paper, the authors first show that if R
0 ≤ 1, the infection free steady state is globally attractive by using approaches different from those given by Min, et al.(2008).
Then the authors prove that if R
0 > 1, the endemic steady state is also globally attractive. Finally, based on a patient’s clinical HBV DNA data of anti-HBV
infection with drug lamivudine, the authors establish an ABVIM. The numerical simulations of the ABVIM are good in agreement
with the clinical data. 相似文献
235.
利用卫星数据和地面光谱测试数据研究地物光谱特征与地球化学成分之间的关系.利用美国陆地卫星Landsat-7的ETM+数据提取研究区的蚀变异常,与区域地球化学水系沉积物测量结果进行关联分析;利用美国光谱分析设备ASD(ASD:FieldSpec-FR),对矿区岩石样品进行光谱测试,提取特征参数并与其化学成分进行对比分析.研究结果表明:卫星数据提取的蚀变异常和化探近矿指示元素Au和Cu等异常空间分布趋势一致;地面光谱测试数据中特征参数H900与Au,Cu,As,Bi,W,Mo和Fe2O3等矿化指示元素具有二次曲线函数的定量关系,这说明在干扰因素少的实验室环境内岩石光谱特征和矿化指示元素之间可以建立定量关系,这种关系支持遥感地球化学测量的开展;现有遥感数据虽不能和矿化指示元素的地球化学异常建立定量关系,但与部分指示元素有很好的相关性,因此,随着遥感技术的发展,遥感数据波段的增加以及去干扰能力的增强,遥感数据也能更精确地反演地物化学成分信息,实现遥感地球化学测量. 相似文献
236.
Hong Zeng Ying Wu Jiuxing Zhang Chunjiang Kuang Ming Yue Shaoxiong Zhou 《自然科学进展(英文版)》2013,23(1):18-22
The electrical resistivity of the as-consolidated and coarse-grained bulk gadolinium(Gd) metals was studied in the temperature range of 3-315K.The experimental results showed that with decrease in the grain size of Gd grains from micrometer to nanometer range,the room temperature electrical resistivity increased from 209.7 to 333.0 μΩcm,while the electrical resistivity at the low temperature of 3K was found to increase surprisingly from 16.5 to 126.3 μΩcm.The room temperature coefficient resistivity(TCR) values were obtained as 39.2×10-3,5.51×10-3 and 33.7×10-3K-1.The ratios of room temperature to residual resistivity [RRR=ρ(300K)/ρ(3K)] are 2.64,11.0,respectively,for the as-consolidated samples at 280℃ and 700℃ with respect to that of the coarse-grained sample.All results indicate the remarkable influence of the nanostructure on the electrical resistivity of Gd due to the finite size effect and large fraction of grain boundaries. 相似文献
237.
238.
鄂尔多斯盆地长庆气田中区马五14储层分为气层、低产水层、中高产纯水层、气水同层、干层五种产层类型,建立了相对应的测井综合判识标准.剖析了马五14气藏的成藏条件,认为燕山中期的构造运动系天然气运移聚集的转折点,后期天然气由西向东运移而聚集在上倾方向致密遮挡带下的圈闭内.研究了马五14储层气、水分布特征及天然气富集规律. 相似文献
239.
匡继昌 《北京教育学院学报(自然科学版)》2009,4(3):1-7
本文所建立的广义Hardy-Hilbert积分算子不等式,是著名的Hilbert不等式的实质性改进和推广,所求出的该算子的范数统一证明了Hilbert不等式各种参数推广中的最佳常数. 相似文献
240.
新课改在教学内容、教学理念、教学方式等方面都有很大变化。然而,面对这么多的新内容、新理念、新模式,教师能否适应呢?教学效果能否保证?通过问卷调查,同时,结合个别访谈、召开小型座谈会和深入课堂听课等方式进行调研发现新课改推进中还存在不少问题:教师、学生普遍反映负担重;新理念难以接受;新模式难以实施。 相似文献