a dark brown humic substance that is soluble in water only at pH values greater than 2;

"the half-life of humic acid is measured in centuries"

the humic acid (ha) was used as the precursors of trihalomethanes(thm), the overall reaction order is second - order.

以腐殖酸为三卤甲烷形成的前驱物质，确定thm生成的反应级数为二级。

the changes of the total amount of humic acid, the free humic acid, the humic acid and the fulvic acid were studied by adding inorganic fertilizer during composting.

研究了在有机肥堆制过程中加入一定量的化肥后腐殖酸总量、游离腐殖酸、胡敏酸、富里酸养分形态发生的转化。

effects of application of sesame cake humic acid and ploughing back of alfalfa and rye grass on the growth and quality of tobacco were studied in the field experiment.

通过田间试验研究了施用芝麻饼肥、殖酸和翻压苜蓿、麦草对烤烟生长发育和烟叶品质的影响。

in this paper, the function of each composition of negative expander is reviewed briefly, and the mechanism and application of organic expander lignosulphonate and humic acid are emphasised.

简述了现代负极膨胀剂各组成部分的功能，重点介绍了负极有机膨胀剂木素磺酸钠和腐植酸的作用机理及应用。

t he obtained data show that:the complex of humic acid and sodium-lignosul phonate can elevate the discharge capacity and rechargeable acceptance ability of lead-acid battery;

试验数据表明：当采用木素磺酸钠为膨胀剂时，最好与腐殖酸复合，这样可提高电池的放电容量和充电接受能力；

humic acid constitutes the main part of organic matter in natural water body, which causes many sanitary and safty problems of drinking water.

腐殖酸是天然水体中有机物的主要组成部分，是引起饮用水卫生和安全问题的重要因素。

the effect of grey humic acid is the weakest.

灰色胡敏酸影响最为微弱。

a new type of compound organic expander composed of humic acid and lignosulphonate at the ratio of 1∶1-3 has been tested.

通过对腐殖酸和木素磺酸盐进行复合试验，确定了其复合比例为1∶1～3。

adsorption of chlorpyrifos on humic acid (ha) of neutral purple soil was studied through balance vibration method.

通过平衡振蕩法研究毒死蜱在中性紫色土腐殖酸（ha）上的吸附。

the influence of extracted and commercial humic acid on trihalomethane formation was studied, and the characteristics of humid acid were analyzed.

以提取腐殖酸和商品腐殖酸为对象，研究了不同腐殖酸对加氯消毒后三卤甲烷生成量的影响，并对腐殖酸特性进行了分析。

humic acid extracted from peat was classified into seven fractions by alcohol precipitation technique for the analysis of thermolysis, flocculation limit and some optical properties.

结果表明，酒精沉淀分级法是按分子量大小、缩合程度的高低将胡敏酸分成较均一的级分，而对胡敏酸的性质、结构等无破坏作用。

organic acids have a great effect on phosphorus mobilization with humic acid stronger than simple organic acids.

有机酸对土壤磷的固定有较大影响，其影响作用从大到小依次为腐殖酸、柠檬酸、酒石酸。

the results showed: fertilization could increase the content of humus, decrease e4/e6, and improve the degree of complexity of humic acid molecule.

结果表明：通过施肥提高腐殖质的含量同时能降低胡敏酸e4/e6值，增加了胡敏酸分子的复杂程度。

conclusion:the humic acid is an important precursor substance of disinfection by products.

结论：腐殖酸是饮用水氯化消毒副产物的重要前体物质。

ir spectra showed that h-bonds and charge-transfer bonds between humic acid and fungicides probably operated as mechanisms of adsorption.

红外谱图显示腐殖酸和杀真菌剂之间的氢键和电荷转移键可能是吸附作用产生的机理。

the results showed that humic acid foliar fertilizer could increase tomato yield by3.43%~ 11.95% compared with ck.

结果表明喷施腐植酸液体叶面肥能增加番茄产量，比对照增产3。43%～11。95%。

the poplar growth and soil enzymatic activity was studied as affected by humic acid fertilizer(nha), which was made by activated brown coal.

利用活化后褐煤腐殖酸为吸附基质制成缓效肥料（nha），研究了其对盆栽杨树生长、土壤酶及理化性质的影响。

jar test was conducted to evaluate the effect of humic acid on residual manganese of permanganate pre-oxidation process.

烧杯搅拌试验表明，水中腐殖酸对高锰酸钾预氧化工艺的剩余锰浓度有重要影响。

mutual effects of calcium magnesium phosphate and humic acid enhance residual lead contents in soil.

钙镁磷肥、胡敏酸互作可增加土壤残渣态铅的含量。