基本物理常数最新推荐值评述

简明地评述了由国际科学技术数据委员会（CODATA）1998年推荐的基本物理常数中得到的一些结论,按CODATA两次推荐的数值,对1998年和1986年的常数值及相应的不确定度进行了比较,并讨论常烽值的变化对物理学和计量学的影响。     

阿伏伽德罗常数的测量及物质的量的新定义

自1971年以来,物质的量摩尔(mol)确定为国际单位制(SI)的7个基本单位之一,由0.012千克碳-12的原子数目定义为1摩尔,由此它与千克的定义具有相关的特性。在千克采用普朗克常数重新定义后,摩尔将采用阿伏伽德罗常数重新定义。文章介绍了重新定义所做的工作及新定义使用的原理和实验测定。这些结果对物理学、化学和计量学均有重要的意义。     

风信子外植体直接再分化花芽的研究——Ⅰ.花芽和营养芽形态发生的控制

本文研究外源激素和外植体对风信子花芽和营养芽再分化的控制。其结果为:(1)对花瓣外植体来说,培养基中附加2,4-D只能诱导形成愈伤组织;附加6-BA能诱导营养芽;附加玉米素能诱导直接再分化花芽。(2)在附加玉米素的培养基上,花瓣和花茎外植体能直接再分化花芽;幼叶和鳞片只能诱导再分化营养芽。(3)在附加玉米素的培养基上,从花瓣外植体再分化的花芽上分离的花瓣可以继续再分化花芽;从花瓣外植体再分化的营养芽上分离的叶切段只能诱导再分化营养芽。结果表明,对于诱导风信子外植体直接再分化花芽来说,培养基中附加玉米素和外植体必须取自花器官是两个关键因素。     

HORMONAL REGULATION OF CALLUS FORMATION IN RELATION TO NUCLEIC ACIDS AND AMINO ACIDS METABOLISM

The cotyledon segments of mung bean were cultured On Miller's medium with or without auxins and cytokinins. It was found that NAA and kinetiu were both required for callus formation and the growth rate increased proportionally to their concentrations. RNA and protein synthesis increased in the early stage of callus formation and the increase of the total RNA was mainly due to the increase of 25S and 18S RNA. In addition, it has been shown that the total amount of free amino acids in the control segments obviously increased after incubation and was larger than that in the callus-forming segments. On the other hand, the amount of protein amino acids in the callus-forming segments was larger than that in the control. Both proline and hydroxyproline existed in the control and callus-forming segments were increased, but the ratio of hydroxyprolinc and proline in the callus-forming segments was tfigher than that in the control.     

生物综合工業(微生物工業)(中)

第二、培養基的條件培養基的功用,一方面是供给菌種生长的需要,另一方面是供给菌種综合产品的原料。其成分可分为两類:第一類为炭水化物,如糖飴,玉黍粉,麥粉,馬鈴薯,紙漿废液,葡萄糖等。這些是酒精,丙酮戊醇,构椽酸,酵母等工業的重要原料。其功用是供给微生物生长的能(Energy)。第二類成分是蛋白性的材料如酪素,玉黍浆(Corn steep)粟米,蛋清,鱼肉,肉膏,蛋白脒,     

基本物理常数的1986年国际推荐值改正情况的说明

本刊1987年第1期发表的基本物理常数的数值是很据1986年7月国际科学技术数据委员会(CO-DATA)成立二十周年会议上发表的数据(由B.N.Taylor和E.R.Cohen编辑).原编者将这些数据在1986年11月的CODATA Bulletin,No.63中发表时,对原来发表的数值和不确定度作了部分修改.现根据其修正情况作如下更正(见表1,表中“页行”栏的数字表示1987年第1期《物理》的页数和行数).基本物理常数的1986年国际推荐值改正情况的说明@沈乃澂     

In vitro TRANSFORMATION OF SUSPENSION CULTURED CELLS FROM Daucus carota BY Agrobacterium tumefaciens STRAIN C58

In vitro transformation of suspension cultured single cells of carrot by Agrobacterium tumefaciens strain C58 was reported here. The results indicate that plant cells with intact cell walls can be directly transformed by A. tumefaciens. At 25℃,and at a ratio of 100 bacteria per plant cell, the transformation frequency was about 10~(-4).The transformed cells had the ability to grow in the absence of plant hormones and very easily regenerated into plants, although nopaline was not detected in the tissues and plants from transformed cells.The differences in the growth rate and regeneration ability between tumors induced by A.tumefaciens strain C58 and hairy roots induced by A. rhizogenes strain A4 on carrot disks were compared.     

燃油燃料含硫化合物形态分布剖析技术研究进展

介绍了目前用于燃油、燃料(如汽油、柴油、煤油、喷气燃料)的硫化物形态分布剖析的多种分析技术,包括电化学方法和气相色谱与多种选择性检测器联用的方法(如GC - FPD、GC - AED、GC - SCD、GC - MS等),并对各种分析技术的研究现状进行了概述.