RATIONALE FOR A UNIVERSAL GENETIC CODE

A mutation in the genetic code would place new amino acids in certain loci and entirely eliminate amino acids from other loci of practically all proteins in an organism. It is reasonable to postulate that mutations of this kind cannot supplant the original code. The genetic code, once established, would therefore remain invariant.     

玉米叶面积指数的普适增长模型

建立了1个模拟叶面积指数动态变化的扩充的Logistic模型,利用禹城、沈阳的玉米叶面积指数(LAI)实测资料进行了拟合,结果表明,此模式是模拟叶面积指数随地理位置、品种、播期、密度变化的统一模型．对叶面积指数与积温间关系的分析,综合了不同地理位置、不同品种、不同播期、不同密度的叶面积指数资料,得到1条相对叶面积指数变化曲线,可反映特定区域作物叶面积指数的动态变化,也可用于区域作物产量模拟和遥感估产的研究。     

玉米叶面积指数的普适增长模型

建立了1个模拟叶面积指数动态变化的扩充的Logistic模型,利用禹城、沈阳的玉米叶面积指数(LAI)实测资料进行了拟合,结果表明,此模式是模拟叶面积指数随地理位置、品种、播期、密度变化的统一模型,对叶面积指数与积温间关系的分析,综合了不同地理位置、不同品种、不同播期、不同密度的叶面积指数资料,得到1条相对叶面积指数变化曲线,可反映特定区域作物叶面积指数的动态变化,也可用于区域作物产量模拟和遥感估产的研究.     

A SYSTEM OF "DEFINITIVE UNITS" PROPOSED FOR UNIVERSAL USE

It is proposed that physicists discard the CGS and Heaviside units, which are responsible for much confusion and needless mental effort, and employ exclusively a single system of "definitive units." The units suggested include the international meter, the international kilogram, the second, the mechanical watt, the international mercury ohm and they conform with the other international units as closely as is compatible with self-consistency. The system is not only definite and absolute, but also comprehensive, readily visualized and, in large part, already employed under well-established names. The system was proposed in 1901 by Giorgi and in 1904 by Robertson but received scant attention on account of the artificial prestige of the CGS system. A single universal system of units should be the ultimate goal, and the "definitive units" are chosen with a view to their adoption not only by all scientists but also by the butcher, the baker and the candlestick-maker. The definitive system of units makes it perfectly feasible to employ a single system much more generally than has ever been the case in the past; the natural ultimate goal is the universal use of these units for all purposes. In the attempt to extend the application of metric units in the United States the meter-stere-kilogram, rather than the meter-liter-gram, should form the basis for legislation, in order to give definitive units their proper legalized status and to secure to the full the advantages of a comprehensive system consistently interrelated with the legalized international electrical units. The gradual discarding of CGS and other redundant units would inevitably follow. Even in the absence of official recognition of definitive units, individuals may advantageously employ the system. This would cause confusion neither to authors nor readers, since these units, in the main, have already acquired vital existence through world-wide, daily use under familiar, well-established names.     

变质量力学系统相对运动的万有Kane方程

本文给出变质量力学系统相对运动的万有 Kane 方程,并由此导出变质量高阶非完整系统相对运动的若干运动微分方程。