铁矿石中水溶性氯化物含量测定不确定度的评定

本文对铁矿石中水溶性氯化物含量测定的不确定度进行评定,分析了不确定度的来源,找出影响测量的各种因素,计算出不确定度分量并提出了该法的合并成不确定度。评定结果显示,测量重复性对测量不确定度影响最大,相比之下,样品称量引入的不确定度分量较小。     

测定铁矿石中全铁含量的三种氧化还原法的对比研究

对测定铁矿石中全铁含量的三种方法;氯化亚锡—氯化高汞重铬酸钾容量法,三氯化钛—重铬酸钾容量法,高氯酸代替氯化高汞重铬酸钾容量法进行了对比研究,三种方法各有其优劣,分析人员在工作中应根据实际情况灵活运用。     

滴定法测定食用油中过氧化值含量

食用油中过氧化值含量过高,即油脂氧化过程中产生的中间产物（过氧化物）含量过高,将致使油的质量品质降低,且对身体非常有害。我国食品卫生标准规定食用植物油过氧化值不得超过0.15%,因此食用油中过氧化物的含量高低直接影响油的品质。     

浅谈滴定法测定食用油中过氧化值含量

食用油中过氧化值含量过高,即油脂氧化过程中产生的中间产物含量过高,将致使油的质量品质降低,且对身体非常有害。我国食品卫生标准规定食用植物油过氧化值不得超过0．15％,因此食用油中过氧化物的含量高低直接影响油的品质。     

电导滴定法测定显影液中亚硫酸钠含量

电导滴定法测定显影液中亚硫酸钠含量北京首都师范大学高静娴亚硫酸钠是显影液中不可缺少的成份，对显影剂起着保护作用，能防止显影液氧化。使用过程中的显影液，随着Ｎａ２ＳＯ３含量的减少，显影剂会加速氧化，显影能力则下降。监测显影液中的Ｎａ２ＳＯ３含量，对分析...     

滴定法测定食品中亚硝酸盐含量的研究

亚硝酸盐含量的测定是食品检测中重要的检测指标之一,现行的检测方法很多。文中采用了滴定法测定食品中亚硝酸盐含量,利用亚硝酸根在酸性条件下跟碘离子反应,生成碘单质,再用硫代硫酸钠滴定法碘单质,间接测定食品中亚硝酸盐的含量。实验中还研究了淀粉用量、不同酸性物质和不同pH等反应条件对回收率的影响。最后研究了此方法测定亚硝酸盐含量的时,食品中其他物质对结果的影响。该方法测亚硝酸盐含量相对偏差为2.4%,限检量为0.30mg/kg。     

重铬酸钾滴定法测定矿石中的铁

在盐酸溶液中,用二氯化锡将Fe（Ⅲ）还原为Fe（Ⅱ）,然后加入氯化汞氧化过量的二氯化锡,以二苯胺磺酸钠为指示剂,用重铬酸钾标准溶液滴定,根据重铬酸钾标准溶液用量计算铁含量。其反应式如下：     

铁矿石总铁量测量不确定度的评估

通过对铁矿石总铁量测量不确定度的评估，对在化学分析中如何进行测量不确定度评估做了探讨。应用因果图分析不确定度分量来源，以全面分析各分量。在按技术规范评估不确定度的同时使用了一种表格计算法。文中讨论了不确定度评估对提高测量水平的指导意义。     

卡尔费休容量滴定法测定饲料中水分含量

建立卡尔费休容量滴定法测定饲料中水分含量方法,该法具有较高精密度和准确度,且操作简单、检测时间短,与国标法(GB6435-1986)相比,无显著性差异,可广泛应用于饲料中水分含量的测定。     

铁矿石中硫的不确定度评定

介绍了不确定度的评定程序及在红外吸收法测定铁矿样品中硫的应用,借助相对不确定度的概念,准确得出了铁矿石中硫的不确定度的评定方法.     

A validated co-simulation of grab and moist iron ore cargo: Replicating the cohesive and stress-history dependent behaviour of bulk solids

The traditional design approach of grabs and other bulk handling equipment consists of manufacturing and testing physical prototypes. A novel design approach is to use a co-simulation of MultiBody Dynamics (MBD) and Discrete Element Method (DEM), in which the virtual prototype of a new concept interacts with bulk solids. Therefore, this study develops and validates a full-scale co-simulation that models the grabbing process of cohesive and stress-history dependent iron ore. First, by executing in-situ measurements during the unloading of a vessel, grab-relevant bulk properties of the cargo, such as penetration resistance, are determined. Second, full-scale grabbing experiments are conducted in the cargo hold, which allows the process to be recorded in realistic operational conditions. Third, full-scale co-simulation is set up using the material model that has been calibrated based on an elasto-plastic adhesive contact model. Fourth, the co-simulation is validated by comparing its predictions to experimental data from various aspects, such as the force in cables and the torque in winches. The validated co-simulation proves that the stress-dependent behaviour of cohesive cargo as it interacts with the grab could be captured successfully. Valuable information such as a grab’s kinematics and dynamics, as well as the porosity distribution of collected bulk solids, can be extracted from the simulation, supporting engineers to enhance the design and operation of equipment.     

分光光度法测定芦荟中铁含量的研究

本文研究了Fe(Ⅱ)—phen—CTMAB—酒石酸氢钾体系测定铁离子含量分光光度法,最大吸收波长515nm,Fe(Ⅲ)含量在0.5～8μg/ml内符合比耳定律,相关系数r=0.9995,摩尔吸光数ε=1.23×10~4L·mol~(-1)·cm~(-1).利用该方法测定库拉索芦荟含铁量,RSD小于0.54％(n=6),回收率98.1％～101.5％。     

Mechanochemical activation of iron ore-based catalysts for the hydrogenation of brown coal

Genesis of pyrrhotite catalysts from different iron ore concentrates and pure iron oxides was investigated using the method of mechanochemical treatment in a planetary mill. The dispersion and fine crystalline structure of oxide and pyrrhotite particles were studied as the function of mechanical load, sulfiding temperature and mode of preparation. Methods for the preparation of high performance iron ore-based catalysts for brown coal hydrogenation have been developed. Received 16 May 2000 / Reviewed and accepted: 8 June 2000     

Computer model simulation study of nanocrystalline iron

This paper provides a computer modelling technique, associated with the molecular statics relaxation method, for the study of nanostructured crystals. Atomistic simulations have been carried out to study the structural features of nanocrystals, such as the reduced mass density, the boundary component proportion, the excess lattice parameter, the excess atomic volume and the radial distribution function. The energy and elastic properties also have been investigated. The simulated results have shown considerable agreement with the experimental results, which implies that the present modelling method is suitable to be used to study the structures and properties of nanocrystals.     

利用X荧光仪测定铁矿中的S，Pb，Zn，As的含量

本文介绍利用X荧光光谱仪测定铁矿中的S,Pb,Zn,As的含量。具有简便、快速、准确、环保等优点,对节省劳力,加强对进厂铁矿质量把关,提高理化检验水平和产品质量都有重大的意义。     

Multifunctional iron and iron oxide nanoparticles in silica

Iron and iron oxide nanoparticles in silica layers deposited by sol–gel techniques on Si wafers were formed and studied. It was shown that multifunctional nanoparticles of different iron oxides possessing various physical properties can be fabricated by means of post-growth annealing of (SiO₂:Fe)/SiO₂/Si samples in various atmospheres. The hematite, maghemite, and iron nanoparticles were found to be dominant upon annealing the samples in air, argon, and hydrogen atmosphere, respectively. The physical properties of produced hybrid structures were studied by Raman and FT-IR spectroscopy, spectroscopic ellipsometry, AFM, and magnetic measurements. The sol–gel technique with subsequent annealing procedure is demonstrated to be an effective method for the formation of multifunctional hybrid structures composed of iron or iron oxide nanoparticles in silica matrix.     

Environmental effects in iron aluminides

Iron aluminides based on the stoichiometric compositions of Fe₃Al and FeAl exhibit poor room temperature ductilities due to hydrogen embrittlement (HE). The presence of surface passive films reduces HE. The reduction is due to the lower rate of hydrogen liberation on the surface of iron aluminides with a passive layer. Theoretical and experimental verification for this idea are provided. The effect of addition of passivity-inducing elements Ti, Zr, V, Nb, Ta, Cr, Mo, W, Si and Ni to Fe₃Al on the thermomechanical and electrochemical behaviour has been outlined. The Cr- and Ti-alloyed intermetallics exhibited significant room temperature ductilities. Microstructural studies of the alloyed intermetallics revealed that when the addition of passivity-inducing element results in the precipitation of brittle phases with Fe and Al, they crack during the processing operation. The addition of oxygen-active elements on the embrittlement behaviour is also discussed. The effect of these additions on the potentiodynamic polarization behaviour and high temperature oxidation behaviour is also briefly addressed. Methods to minimize HE by the addition of elements that irreversibly trap hydrogen and that prevent recrystallization have also been discussed.     

井下硐室大爆破实践

酒钢镜铁山矿运用硐室大爆破处理山头岩体，以便为２号（中）矿体的开采形成良好的覆盖层。由于爆破设计合理，工程质量较好，达到了预期的目的。     

A bond-order potential for atomistic simulations in iron

A new semi-empirical potential for Fe based on the quantum chemistry concept of bond order has been developed. The potential consists of two parts: the repulsive short-range exponential potential, and the attractive potential, also of the exponential form, with a bond-order prefactor. The latter depends on angles between the Fe-Fe bonds, and uses the environmental parameter similar to that of the Tersoff bond-order potential for tetrahedrally bonded semiconductors. The bond order function (depending on the above environmental parameter), however, is of a more general form than that of the Tersoff potential. The new potential was calibrated using the traditional fitting to the Universal Scaling and the equilibrium volume and cohesive energy of BCC Fe. The introduced 'punishment functions' also directed the multi-variate minimization process towards minimizing the deviations between the calculated and experimental values of the elastic moduli C′ and C₄₄, the energies of FCC and HCP Fe modifications, and the (111) free surface energy. With the total of 15 fitted parameters, the potential reproduces with only minor deviations the elastic moduli, the volume–pressure equation of states in BCC phase, the energies in FCC and HCP modifications, the BCC-HCP phase transformation under pressure, and the energy of the (111) free surface. Other tests of the new potential are being currently performed. The potential will be used in atomistic simulations of lattice stability, and deformation and chemisorption processes in Fe. This revised version was published online in July 2006 with corrections to the Cover Date.     

在氧化铁表面沉积热解炭及其气化与还原

采用流动反应器研究了丙烯热解和在铁黄颗粒表面生成热解炭的化学热力学以及化学气相沉积（CVD）过程。发现在600oC之前丙烯热解发生的化学气相沉积基本为表面反应过程；在热解炭沉积过程中铁黄颗粒的比表面积迅速减少，同时由于脱去水分而发生失重；随着温度的升高，Fe2O3逐渐被还原为Fe3O4和FeO，在800℃以上Fe2O3完全被还原为Fe3C。在化学气相沉积过程中，500℃以前铁黄可以保持大长径比形貌，在600℃～700℃之间则生成长径比较小的哑铃型颗粒。非球形氧化铁颗粒在氢气还原过程中能够保持原有形状，同时被还原成为单质铁。上述化学气相沉积和气化过程可以用于制备热解炭包覆的或者纯净的非球形铁颗粒材料。