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钢铁中的氮元素,按鞍钢冶金研究院编的《实用冶金分析》及原机械工业部编的二级理化人员学习教材中的方法均无法测定,能否提供氮的测定方法?
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作者 陈景南 《理化检验(化学分册)》 CAS CSCD 北大核心 2001年第6期270-271,274,共3页
关键词 钢铁 分析方 光度法测定法
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MnSO_4-CuSO_4复合催化剂快速测定COD的研究 被引量:2
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作者 杨洋 金振兴 《辽宁工学院学报》 2007年第5期316-318,321,共4页
探讨了以MnSO4-CuSO4复合催化剂代替标准重铬酸钾法中的Ag2SO4,用H2SO4-H3PO4混酸代替标准重铬酸钾法中的硫酸,测定化学需氧量的最佳条件为:氧化剂K2Cr2O7浓度为0.25 mol/L,混酸H2SO4-H3PO4体积比为4∶1,催化剂MnSO4-CuSO4配比为1∶2,Mn... 探讨了以MnSO4-CuSO4复合催化剂代替标准重铬酸钾法中的Ag2SO4,用H2SO4-H3PO4混酸代替标准重铬酸钾法中的硫酸,测定化学需氧量的最佳条件为:氧化剂K2Cr2O7浓度为0.25 mol/L,混酸H2SO4-H3PO4体积比为4∶1,催化剂MnSO4-CuSO4配比为1∶2,MnSO4与CuSO4的总量为0.03 g,消解温度为165℃,消解时间为15 min,实验相对误差≤5%. 展开更多
关键词 化学需氧量 分光光度法:重铬酸钾:快速测定
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Simultaneous Determination of Iron and Manganese in Water Using Artificial Neural Network Catalytic Spectrophotometric Method 被引量:4
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作者 JI Hongwei XU Yan +2 位作者 LI Shuang XIN Huizhen CAO Hengxia 《Journal of Ocean University of China》 SCIE CAS 2012年第3期323-330,共8页
A new analytical method using Back-Propagation (BP) artificial neural network and kinetic spectrophotometry for simultaneous determination of iron and magnesium in tap water, the Yellow River water and seawater is est... A new analytical method using Back-Propagation (BP) artificial neural network and kinetic spectrophotometry for simultaneous determination of iron and magnesium in tap water, the Yellow River water and seawater is established. By conditional experiments, the optimum analytical conditions and parameters are obtained. Levenberg-Marquart (L-M) algorithm is used for calculation in BP neural network. The topological structure of three-layer BP ANN network architecture is chosen as 15-16-2 (nodes). The initial value of gradient coefficient μ is fixed at 0.001 and the increase factor and reduction factor of μ take the default values of the system. The data are processed by computers with our own programs written in MATLAB 7.0. The relative standard deviation of the calculated results for iron and manganese is 2.30% and 2.67% respectively. The results of standard addition method show that for the tap water, the recoveries of iron and manganese are in the ranges of 98.0%-104.3% and 96.5%-104.5%, and the RSD is in the range of 0.23%-0.98%; for the Yellow River water (Lijin district of Shandong Province), the recoveries of iron and manganese are in the ranges of 96.0%-101.0% and 98.7%-104.2%, and the RSD is in the range of 0.13%-2.52%; for the seawater in Qingdao offshore, the recoveries of iron and manganese are in the ranges of 95.3%-104.8% and 95.3%-104.7%, and the RSD is in the range of 0.14%-2.66%. It is found that 21 common cations and anions do not interfere with the determination of iron and manganese under the optimum experimental conditions. This method exhibits good reproducibility and high accuracy in the determination of iron and manganese and can be used for the simultaneous determination of iron and manganese in tap water and natural water. By using the established ANN- catalytic spectrophotometric method, the iron and manganese concentrations of the surface seawater at 11 sites in Qingdao offshore are determined and the level distribution maps of iron and manganese are drawn. 展开更多
关键词 artificial neural network simultaneous determination kinetic spectrophotometric method iron MANGANESE
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Determination of Cholesterol Content in Waste Fat by Dual-wavelength Spectrophotometry
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作者 LIU Jia-di XU Shu-jun +1 位作者 XU Chun-xiang QIN Jin-ping 《Chinese Food Science》 2012年第2期40-42,共3页
[Objective]The aim was to find a way to measure the cholesterol content in deserted oil.[Method]Dual-wavelength spectrophotometry method was used for the determination of cholesterol in edible oil.630 nm and 720 nm we... [Objective]The aim was to find a way to measure the cholesterol content in deserted oil.[Method]Dual-wavelength spectrophotometry method was used for the determination of cholesterol in edible oil.630 nm and 720 nm were set as target band and reference band in this method,respectively.The result was compared to liquid chromatography method.[Result]The relative standard deviation(RSD)was at 1.26% and recovery was between 101.9% and 110.7%.Linear range was 8.0-40.0 μg/ml.The tested result was close to the result of liquid chromatography.[Conclusion]It was proved that this method was easy,fast and accurate.The disturbance of sitosterol was eliminated without isolation.It can be used for fast identification of the authenticity of waste fat. 展开更多
关键词 Dual-wavelength Spectrophotometry Waste fat CHOLESTEROL SITOSTEROL China
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STUDY ON THE DETERMINATION OF TRACE Fe(Ⅲ) BY THIN LAYER RESIN PHASE SPECTROPHOTOMETRY
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作者 HOU Yanmin YANG Yongsheng +1 位作者 XIE Jimin HUANG Weihong 《Chinese Journal of Reactive Polymers》 2007年第1期80-84,共5页
A method to determine Fe(Ⅲ) by thin layer resin phase spectrophotometry has been developed in this paper. The colored complex formed by Fe(Ⅲ) and 1,2-benzendiol is concentrated on the 717^# resin, then Fe(Ⅲ) ... A method to determine Fe(Ⅲ) by thin layer resin phase spectrophotometry has been developed in this paper. The colored complex formed by Fe(Ⅲ) and 1,2-benzendiol is concentrated on the 717^# resin, then Fe(Ⅲ) can be determined directly by making thin layer. The method is sensitive with a apparent molar absorption of 4.8×10^4L/mol.cm, which is 16 times higher than that of liquid phase spectrophotornetry, most coexisting ions do not influence the determination. The detection limit for Fe(Ⅲ) is 1.47μg/L with the precision of 3.3% [n=6, 7μg/50mL Fe(Ⅲ)]. The calibration curve is linear in the range of 0-25μg/50mL. The preposed method was applied to the determination of Fe(Ⅲ) in water sample with satisfactory results. 展开更多
关键词 1 2-benzendiol Thin layer resin phase spectrophotometry Fe(Ⅲ).
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A Novel 360°3D Profilometry
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作者 SONG Yuanhe,ZHAO Hong,FAN Hua,CHEN Wenyi,TAN Yushan (Research Institute for Laser & Infrared Applications, Xi’an Jiaotong University,Xi’an 710049,CHN) 《Semiconductor Photonics and Technology》 CAS 1998年第1期45-49,共5页
A new method of 360° turning 3D shape measurement in which light sectioning and phase shifting techniques are both used is presented in this paper.A sine light field is applied in the projected light stripe,meanw... A new method of 360° turning 3D shape measurement in which light sectioning and phase shifting techniques are both used is presented in this paper.A sine light field is applied in the projected light stripe,meanwhile phase shifting technique is used to calculate phase of the light slit.Thereafter wrapped phase distribution of the slit is formed and the unwrapping process will be made by means of the height information based on the light sectioning method.Therefore phase measuring results with better precision can be obtained.At last the target 3D shape data can be produced according to geometric relationships between phases and the object heights.The principles of this method are discussed in detail and experimental results are shown in this paper. 展开更多
关键词 Light Sectioning Phase Shifting Phase Unwrapping Algorithm 3D Shape Measurement
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Escamoles Ant Eggs Liometopumapiculatumm Source of Metal Ions for Human Health 被引量:1
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作者 Virginia Melo Concepcion Calvo +2 位作者 Tomas Quirino Susana Macin Ileana Muniz 《Journal of Chemistry and Chemical Engineering》 2013年第6期556-559,共4页
The earth crust is believed to be made of a mass of minerals and is matched by their importance in human life. The human body, depend like other leaving organisms, on several minerals as essential constituents of its ... The earth crust is believed to be made of a mass of minerals and is matched by their importance in human life. The human body, depend like other leaving organisms, on several minerals as essential constituents of its existence. Metal ions in foodstuff are in different chemical forms, as inorganic salts or organic molecules or complexes with other compounds such as proteins, amino acids, enzymes and some vitamins, among others, that play an important role in human health. Entomophagy, insect consumption by several ethnic groups in Mexico as cultural tradition since prehispanic era represent an option for population to obtain the minerals needed by the body to keep a good health. Escamoles ant eggs of the Liometopumapiculatum M genus, much appreciated either at rural communities as well as in urban cities, contain minerals with a favorable effect in human health. The aim of this study was to investigate the mineral composition of Escamoles and the benefits which can provide to the human body. Sampling was at an arid region of the Hidalgo state on April 2012. Minerals in dry basis, determined by atomic absorption spectrophotometry, with the exception of phosphorus content, obtained from a triple acid digested extract and determined colorimetrically. Data of mineral analysis in dry basis of Escamoles were: total minerals 5.92%; Na 0.079%; K 0.075%; Ca 0.097%; P 0.701%; Fe 0.021%; Zn 0.035% Cu 0.009%; Mg 0.998%; Mn 0.002%. Minerals quantify are not equal to total ash contained because not all of them were assess determined. Elements concentration depends not only on the total mineral composition of foodstuff the inorganic or organic form or interaction among metal ions, but also on their availability and avail of them. Minerals in Escamoles ant eggs have a considerable influence in the condition of human health. 展开更多
关键词 Escamoles ant eggs metal ions human health.
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Detection of Total Phenols, Essential and Toxic Elements in Latvian Whole Grain Bread
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作者 Natalia Bobere Anton Podjava Ida Jakobsone 《Journal of Chemistry and Chemical Engineering》 2012年第1期1-6,共6页
A survey was carried out with the aim of assessing the level of the total phenolic compounds (TPC), essential (Na, K, Ca, Mg, Cu, Zn) and toxic (Cd and Pb) elements in 10 Latvian whole grain rye and/or wheat flo... A survey was carried out with the aim of assessing the level of the total phenolic compounds (TPC), essential (Na, K, Ca, Mg, Cu, Zn) and toxic (Cd and Pb) elements in 10 Latvian whole grain rye and/or wheat flour bread samples, obtained from the local market. The quantities of the TPC were determined by spectrophotometry. Mineral content was determined by flame photometry, flame atom absorption spectrometry (FAAS) and electrothermal atomic absorption spectrometry (ETAA) after wet digestion in concentrated HNO3. The values were comparable to the literature data. The average content in all the samples was (on a basis of weight of the product) 547 ± 28 mg/100 g for Na; 280 ±20 mg/100 g for K; 32 ± 2 mg/100 g for Ca; 88 ±5 mg/100 g for Mg; 0.49 ± 0.09 mg/100 g for Cu; 1.6 ±0.2 mg/100 g for Zn. Both Pb and Cd were determined below the limit of detection (LOD 5 0.10 mg/100 g). The LOD values were determined for each element. The TPC content in defatted samples was slightly lower than the non-defatted ones, showing the dependence on the sample preparation. The calculated average levels of the elements were compared with the maximum levels recommended or regulated by the national legislation. 展开更多
关键词 Essential and toxic elements whole grain bread flame photometry FAAS ETAA total phenols spectrophotometry.
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