失效农药的鉴别

粉剂型农药:如药粉已明显结块或用手能捏成团块,说明已经失效或即将失效. 乳剂型农药:这类农药是乳油状态,在正常条件下贮存不分层,不沉淀,表明未失效.如有分层式沉淀现象,可取净水1杯,徐徐将农药注入1～2mL,搅拌沉淀物,如果底部有沉淀,油与水分层明显,并有漂浮物,说明乳化性不良,部分已失效.     

油脂酸败及对健康的影响

油脂在加工、贮藏条件不当或时间太久，就会引起酸败。感观鉴别会有刺激性气味和异昧，检测得知，这种油脂中的游离脂肪酸含量和过氧化值增高，其它指标沉淀物、透明度、色泽气味都与原来不同。油脂的这种劣变现象称为酸败。引起油脂酸败的因素很多，例如加工时的原料及贮藏当中徽生物、光、热、水、金属、空气等的影响。     

春养仔猪保安全 科学补铁是关键

仔猪的春季死亡率较高,其中一个很关键因素就是缺铁。科学补铁是提高仔猪存活率的重要手段。铁元素是猪体中重要的微量元素之一,是合成血红蛋白、肌红蛋白和多种氧化酶的重要原料。如果猪体中缺乏这种原料,仔猪就会发生缺铁性贫血。据资料表明,初生仔猪体内储     

真假化肥的简易鉴别

一、硝酸钾的鉴别 1.取少许样品放在烧红的铁片或木炭上,既不熔化,也不燃烧,又不释放出特别的气味,并能溶于水的为真品.2.在其水溶液中加入氯化钡溶液,立即产生白色沉淀物的为真品,反之则为伪劣产品.     

排泥水沉淀物与废弃果渣制备生物肥料的pH值试验

[目的]以排泥水泥淀物和废弃果渣为原料制取生物肥料。[方法]以水厂排泥水沉淀物、废弃果渣为培养基的主要原料,接入酵素菌,通过固体发酵,使其转化为生物肥料。[结果]试验表明,pH值在整个菌种生长繁殖过程中起决定性作用,pH值在6.8以上时,菌种无法生存和繁殖。[结论]排泥水沉淀物、废弃果渣用量对培养基的pH值影响很大。     

沉积物供给对互花米草盐沼的影响

During the past century, natural and human modifications of environmental systems have greatly accelerated coastal salt marsh deterioration and shoreline retreat in many regions worldwide. Field investigation, profile analysis, geographical information analysis, and remote sensing were employed in combination to study the effect of sediment on Spartina alterniflora salt marshes of the coast in Jiangsu Province, East China. The results indicated that the propagation of Spartina alterniflora salt marshes was closely related to regional sediment conditions, especially the supply of fine-grained materials. Additionally, because of the dense and high grass in Spartina alterniflora salt marshes, wave energy and tidal currents were baffled and weaker than those of the adjacent, unvegetated mud flats. Fine sediment was hardly resuspended under the low energy conditions in the Spartina alterniflora salt marshes.     

底泥疏浚对磷形态和磷释放的影响

A laboratory experiment was carried out through a six-month incubation of undredged （control） and dredged cores to study the effect of sediment dredging on phosphorus （P） release from the sediment in the Taihu Lake. During the experiment, dredging the upper 30 cm layer could efficiently reduce the interstitial PO4^3-P concentration and different P forms in the sediment. The P fluxes of the undredged and dredged cores ranged from -5.1 to 3047.6 and -60.7 to 14.4μg·m^-2·d^-1, respectively. The fluxes of the dredged cores were generally lower than those of the control. Differences in the fluxes between the dredged and undredged cores were statistically significant （P 〈 0.05） from March to June 2006. The sediment P in the dredged cores had a lower release potential than that in the control. Dredging can be considered as a useful measure for rehabilitating the aquatic ecosystem after the external P loading in the Talhu Lake catchment was efficiently reduced.     

饲料中甲基紫,沉淀物和粗蛋白变异系数间相互关系的研究

本试验先后用国标（ＧＢ５９１８－８６）规定的甲基紫法和沉淀法对立式混合机不同混合时间８组９６个配合饲料样品进行了混合均匀度的测定，并对其粗蛋白的变异系数进行了分析。结果表明：三者变异系数（ＣＶ％）间差异极显著（Ｐ〈０．０１），不能等同。因此，国标两法所测的饲料混合均匀度不代表饲料中营养成分粗蛋白的混事均匀度。研究还发现，沉淀物的ＣＶ％（ｘ）与粗蛋白的ＣＶ％（ｙ）间呈显著相关，二者回归公式为：ｙ＝１     

如何鉴别黄芪多糖原粉

<正>(上接09年第2期)3、黄芪多糖中是否掺入葡萄糖的鉴别:虽然目前常用的检测方法无法分别检测黄芪多糖中不同分子量的糖的含量,但通过80%酒精醇沉法可鉴别黄芪多糖中是否加入了葡萄糖。检测方法:取黄芪多糖10克,用60毫升水稀释,再加入240毫升纯酒精,搅匀静置,观察沉     

流沙一样的声音

2009年12月10日，记者在一瓶印有“河南省平舆天方永乐酒业有限公司”的“小方瓶酒”里，发现了一些沉淀物和一只小飞虫，查看同箱其他酒，有的瓶里面也有杂质。