用碱煮法测定青橡胶草中橡胶之含量(续)——部分Ⅱ:一二年生鲜草根

为了进一步试用碱煮法测定含胶量的方法,我们在五三年进行一二年生橡胶草溶剂法的同时,又进行了碱煮法的试验。由结果证明在一定条件下,此法用于一二年生草根是可以的。我们本次所用的原料是这样的:将草根分为大中小碎根四部分,即B_1B_2B_3B_4,其中B_1B_2多系草根头部,带叶子很多,因而我们做了不去杂(草     

用气相色谱法与高效液相色谱法分析橡胶中物质含量之比较

用气相色谱法和高效液相色谱法分析橡胶配方时，两种方法各有利弊，但使用两种方法可以优势互补，洗出液的组分及pH值对Jian定和分离胶料中的成分有很大作用。     

用WL-15型微处理机离子计——以固体样加入法快速测定钾肥中钾含量

由WL-15型微处理机离子计具有自动计算Cx=(10△S/E-1)Cs的功能,在已知电极的响应斜率后,先测定标准含钾溶液的电位E_1,再在此溶液中加入50毫克钾肥产品,经溶解搅匀测得电位E_2,将这数据输入后即能自动算出50毫克样品中钾的含量。本方法适用于含钾量大于25％的钾肥样品,由于所用的钾电极对钠的选择性系数为4.4×10~3,对钙和镁的选择性系数分别为3.0     

硬木中流体移动的双尺度多孔机理的依据(Ⅰ)用多色X光束测定榉木浸润中湿含量的演变

An experimental device able to determine the moisture content of wood using X-ray attenuation is usedto study the imbibition of beech samples (Fagus silvatica). The apparatus includes an X-ray generator, a protectivetube, collimating plates and a 50 mm detector. Detected particles can be categorised by energy (accuracy of theorder of 20%) or by position (accuracy 100μm). The independent choice of both the energy spectrum (throughthe voltage) and the counting rate (through the current intensity) makes the installation very flexible. However,a rigorous treatment is necessary to deal with the attenuation of a polychromatic spectrum. The appropriatecalculations are presented and validated with homogeneous samples made of wood and water. In addition, someresults are presented with samples heterogeneous in density and moisture content. Finally, the experimental deviceis used to study the evolution of moisture content during saturation experiments, for which the moisture migrationis mainly due to capillary forces. The geometrical configuration was so arranged that the transfer can be studied intwo directions simultaneously.     

国际标准ISO 19822:2018肥料与土壤调理剂 ——肥料物质中腐植酸和疏水性黄腐酸含量的测定

腐植酸类物质(或译为"腐殖物质")存在于海洋、河流、湖泊和土壤表层等所有生态系统中.这些系统中存在的腐植酸类物质的量化处理,对于学术研究和商业运作,特别是对农业土壤和作物管理来说都是至关重要的. 农业中腐植酸类物质使用量的增加,促使生产者、消费者和监管机构对采用一种可靠的方法来定量腐植酸类物质原矿和商业肥料产品中的活性...