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王晶晶 《国际沙棘研究与开发》2022,8(2):45-48
含氮化合物是水体污染监测中的重要指标,因此需要可靠精确的检测方法作为支撑.本文采用气相分子吸收光谱法对亚硝酸盐氮、硝酸盐氮、总氮进行检测分析,结果表明:标准曲线相关系数均大于0.999,检出限、精密度、准确度、加标回收率均满足方法要求.表明气相分子吸收光谱法具有较高的灵敏度和准确度,稳定性好,可实现样品在线自动稀释和在... 相似文献
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为提高气相色谱法检测食用植物油中残留溶剂(六号溶剂)的准确性,介绍该法的检测原理、所需试剂设备、标准溶液配置步骤、分析条件以及结果计算方法,从温度、进样方法、进样量等方面,探讨检测过程中需要注意的问题和应采取的措施. 相似文献
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比较水质分析中酶底物法、纸片快速法这两种不同方法对总大肠菌群的检测效果。对2个有证标准样品(3 100 MPN/L和3 700 MPN/L)进行检测,考察上述两种方法的准确度;对低(400 MPN/L)、中(1.0×104MPN/L)、高(3.0×106MPN/L)3个细菌总数浓度样品进行检测,考察两种方法的适用性。结果表明:酶底物法的准确度更高;酶底物法适用于低中浓度细菌水样,纸片快速法适用于高浓度细菌水样。可根据实验准确度要求和不同水质污染程度选取合适的方法,以满足水质分析要求。 相似文献
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原子吸收光谱分析仪器几乎能分析所有的金属元素和类金属元素,应用越来越广泛.在概述原子吸收光谱分析法工作原理的基础上,详细介绍了原子吸收光谱分析仪器主要部件(光源、原子化器、分光系统、检测系统和电脑系统)的结构、功能及特点,旨在为分析测定工作者提供相关的理论参考. 相似文献
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在处理电镀废水的时候,常用的方法有中和沉淀法、硫化物沉淀法、离子交换法以及多硫化钙处理法等。本文根据这几种不同沉淀的方法的具体做法以及缺点和优点分别进行探讨,并且提出了出现处理问题时应该选择什么样的方式解决重金属污染问题。 相似文献
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提出了一种基于光纤锥视觉的植物叶片检测方法,通过光纤锥与CCD 传感器耦合成像获取植物叶片图像。由于叶脉复杂多变的特点,因此采用3种叶脉提取的方法,即迭代阈值法、一维信息熵法和传统的自适应阈值分割法,并用这3种方法分别对两种树叶进行叶片脉络图像提取。利用 K-均值算法,针对叶片脉络图像的7个不变矩信息进行聚类,分析这3种阈值方法的优劣。实验结果表明,这3种方法都可以提取出比较理想的叶脉络和叶边缘信息,但迭代阈值法和自适应阈值法更有利于植物物种识别。 相似文献
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车轮平衡度就车检测的方法有三种:低频检测、共振法检测、预加平衡块法检测。在就车检测中对车轮的振动特性进行分析的基础上,对三种检测方法的检测原理,即确定平衡块质量及其位置的方法进行了分析,并对其优缺点进行了评价,为车轮平衡就车检测提供了理论依据。 相似文献
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感官检验棉花的品级,这是农村常见的一种检测手段.它的一个主要特点就是存在不确定性.这是由于检验员的品级检验水平存在一定的差异,其中有很多因素制约着检验的结果.文章对影响感官检验结果的因素进行了系统的分析. 相似文献
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《Journal of Agricultural Engineering Research》1998,69(3):249-254
A model to represent the discolouration of dried powder of carrots as a function of temperature was developed. Two types of carrots, Asian and European, containing large amount of lycopene and β-carotene, respectively, were tested. The dried powder was stored under an atmosphere with O2and at three different temperatures, 5,20 and 35°C. The surface colour of the powder was monitored during storage by a Hunter colour ratioa/b. In the proposed model, the rate of oxidation was assumed to be represented by the product of the fraction of concentration of oxidized pigment at arbitrary time and a specific rate of oxidation of pigment. The rate parameters in the proposed model were calculated by fitting the experimental data with smooth curves by trial and error at the end of the induction period but before discolouration took place. The frequency constant and activation energy, expressing the temperature dependence of the rate parameters, were expressed by the Arrhenius relation. The simulation results of a Hunter colour ratioa/bof dried powder at 25°C showed good agreement with the experimental data, suggesting that the proposed model was effective for the prediction of discolouration of dried powder of both types of carrot. The use of the induction period in the manner described may enable the shelf life of dried powder to be predicted. 相似文献
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从灾害经济学的角度探讨了城镇供水优化调度的必要性和可能性，认为在缺水不可避免的情况下，对供水进行优化调度可以减小缺水带来的损失，产生较好的减灾效益，特别是可以大大减小严重干旱的灾害效应。并根据水资源的特性，提出了缺水损失的计算模式以及优化调度的原则和方法。 相似文献
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The fractional outflow rate of water from the rumen, measured as the rate of disappearance of the chromium complex of ethylenediamine tetra-acetic acid, was related to a number of dietary factors. A multiple regression equation was derived which expressed fractional outflow rate as a function of the intakes of dry matter, ash, acid-detergent fibre and crude protein.The data analysed consisted of 243 observations for sheep on 59 diets, including forage, concentrate and mixed diets. The ranges covered by the data were: fractional outflow rate 0.7–3.6 day?1; dry matter intake 560–1400g/day; ash 4–30%, acid-detergent fibre 7–41%, crude protein 5–26 % of dry matter; there were no observations for sheep of less than 34 kg liveweight.The equation accounted for 56·3 % of the total variance. Between-sheep variance could not be calculated for the whole of the data but was undoubtedly substantial since, for a sixth of the data, it was known to account for 38 % of the total variance. 相似文献