过量Fe2+对水稻生长和某些生理性状的影响

通过溶液培养研究了不同浓度氧化亚铁 (Fe2+)胁迫对水稻的生长、叶绿素含量及抗氧化酶活性的影响。结果表明 ,高浓度的Fe2+ 胁迫明显抑制水稻地上部和根系的生长、降低下位叶片叶绿素含量。当介质中Fe2+浓度过高时 ,水稻植株体内过氧化物酶 (POD)、过氧化氢酶 (CAT)和硝酸还原酶 (NR)活性明显受抑。然而 ,低浓度Fe2+胁迫时 ,上述酶活性反而提高 ,这可能是水稻抵御亚铁毒害的一种适应性机制。     

Rate Constants for Charge Transfer Across Semiconductor-Liquid Interfaces

Interfacial charge-transfer rate constants have been measured for n-type Si electrodes in contact with a series of viologen-based redox couples in methanol through analyses of the behavior of these junctions with respect to their current density versus potential and differential capacitance versus potential properties. The data allow evaluation of the maximum rate constant (and therefore the electronic coupling) for majority carriers in the solid as well as of the dependence of the rate constant on the driving force for transfer of delocalized electrons from the n-Si semiconducting electrode into the localized molecular redox species in the solution phase. The data are in good agreement with existing models of this interfacial electron transfer process and provide insight into the fundamental kinetic events underlying the use of semiconducting photoelectrodes in applications such as solar energy conversion.     

用偏振荧光法研究棉纤维细胞壁非晶区物质的分子取向

将荧光分子导入棉纤维细胞壁的非晶区,用偏振荧光分光光度计测量其荧光强度偏振分量的角分布,据此求出细胞壁非晶区物质的取向度.结果表明:非晶区物质中的分子取向不是随意的.用偏振荧光法测定陆地棉纤维中非晶区物质的取向度f为0.2左右.在荧光剂浓度为0.01％条件下,浸渍时间至少需要48h.     

Vorticity analysis associated with drafting cylinders for pneumatic spinning

Traditional spinning systems have reached profitability limits in developed countries due to high production costs and low system productivity. Pneumatic spinning is seen as a developing system, because productivity is much higher than conventional systems. This study evaluates one of the main problems to increase productivity in pneumatic spinning, where air mass-flow is dragged by the drafting cylinders. This flow interacts with the incoming fibres deviating them from their expected path. Via laser anemometry, airflow velocity distribution around drafting cylinders has been measured and it has been found that vorticity is created at the cylinder’s inlet. Extensive CFD simulation on the air flow dragged by the cylinders has given a clear insight into the vortex created, producing valuable information on how cylinder design affects the vorticity created. Several drafting cylinder designs have been tested without giving any improvement in productivity. However, the use of a drafting cylinder with holes in it produced good results to the problem of air currents, strongly reducing them and therefore allowing a sharp increase in yarn quality, as well as an increase in productivity. An extensive study on vortex kinematics has been undertaken, bringing with it a better understanding of vortex creation, development and breakdown.     

Estimating energy balance fluxes above a boreal forest from radiometric temperature observations

The great areal extent of boreal forests confers these ecosystems potential to impact on the global surface-atmosphere energy exchange. A modelling approach, based on a simplified two-source energy balance model, was proposed to estimate energy balance fluxes above boreal forests using thermal infrared measurements. Half-hourly data from the Solar-Induced Fluorescence Experiment, carried out in a Finnish boreal forest, was used to evaluate the performance of the model. Energy balance closure, determined by linear regression, found all fluxes to underestimate available energy by 9% (r² = 0.94). Significance in the energy balance of the heat storage in the air and in the soil terms was also analyzed. Canopy temperatures, measured by a CIMEL Electronique CE 312 radiometer, together with ancillary meteorological variables and vegetation characteristics, were used to run the model. Comparison with ground measurements showed errors lower than ±15 W m^?2 for the retrieval of net radiation, soil heat flux and storage heat flux, and about ±50 W m^?2 for the sensible and latent heat fluxes. A sensitivity analysis of the approach to typical operational uncertainties in the required inputs was conducted showing the necessity of accurate measurements of the target radiometric surface temperature.     

小麦根系发生规律的研究

1984～1987年对小麦不同品种、密度和施氮水平下根系发生规律进行观察.结果表明:主茎叶片出生与各叶节次生根开始发生存在(n-3)的同伸关系.各叶节发根力随节位提高而增强.芽鞘节、分蘖鞘节、主茎的1～4叶节和分蘖的1～2叶节一般发根1～2条,其余各叶节可发根2～6条,抱茎叶节最多可发根6～8条.不同密度和施氮量主要影响最上3个叶节的发根力.     

几个含源守恒律方程的精确孤波解

从KdV方程、MKdV方程的孤波解出发,获得了带非均匀项的KdV方程和带非均匀项的MKdV方程的精确孤波解。     

各向异性恒定磁场的广义变分原理

用传统的Lagrange乘子法建立了一类新的线性与非线性各向异性恒定磁场的广义变分原理。     

用萤光抗体试验筛选能表达鸡马立克病病毒pp38基因的重组昆虫杆状病毒

用抗鸡马立克病病毒(MDV)的38Kd磷蛋白的单克隆抗体作萤光抗体试验,直接从用可转染性野生型杆状病毒AcMNPV株DNA与含MDVpp38基因的重组转基因质粒载体DNA共同转染的Sf 9单层细胞培养中筛选到能表达pp38基因产物的重组杆状病毒感染斑,并从保存于琼脂醣凝胶上的复印斑中收复并进一步克隆了该基因重组病毒.该法易于实施,即使未能熟练掌握根据杆状病毒多角体来区别野生型杆状病毒斑与基因重组病毒斑的技术,也可顺利地筛选到能表达目的基因的重组合病毒。     

苏新棕壳蛋鸡自别雌雄配套系的研究——雏鸡羽色自别雌雄准确率的测定

对苏新A、B(均带有金色基因)、C、D(均带有银色基因)4个纯系按A■×B■A■×C■、A■×D■、B■×D■、AB■×CD■等5个组合进行测定。结果表明雏鸡羽色自别雌雄准确率均在98.2％以上,证明纯系的羽色基因已高度纯合。同时观察确定了商品代雏鸡羽色自别标准型。公雏羽色:全白色或白头身有棕色斑点;白头、淡黄身;白头、背部有浅灰色到深灰色条纹。母雏羽色:全棕色;棕头、白身;棕头、棕条背、白身。