Element distribution and difusion behavior in Q&P steel during partitioning

Carbon, manganese, and silicon distribution in quenching and partitioning （Q＆P） steel during partitioning process was investigated to reveal the diffusion behavior. The microstructure and chemical composition were analyzed by means of scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, and three-dimensional atom probe. It is shown that the studied Q＆P steel consisted of martensite laths and thin, film-like retained austenite showing extraordinary phase transformation stability. Carbon atoms mostly diffused to the retained austenite from martensite at a higher partitioning temperature. In the experimental steel partitioned at 400℃ for 10-60 s, carbides or cementite formed through carbon segregation along martensite boundaries or within the martensite matrix. As a result of carbon atom diffusion from martensite to austenite, the carbon content in martensite could be ignored. When the partitioning process completed, the constrained carbon equilibrium （CCE） could be simplified. Results calculated by the simplified CCE model were similar to those of CCE, and the difference between the two optimum quenching temperatures, where the maximum volume fraction of the retained austenite can be obtained by the Q＆P process, was little.

Effect of chemical composition on the element distribution,phase composition and calcification roasting process of vanadium slag

The chemical composition of vanadium slag significantly affects its element distribution and phase composition,which affect the subsequent calcification roasting process and vanadium recovery.In this work,seven kinds of vanadium slags derived from different regions in China were used as the raw materials to study the effects of different components on the vanadium slag’s elements distribution,phase composition,calcification roasting,and leaching rate of major elements using scanning electron microscope,X-ray diffraction analysis,and inductively coupled plasma-optical emission spectroscopy.The results show that the spinel phase is wrapped with silicate phase in all vanadium slag samples.The main elements in the spinel phase are Cr,V,and Ti from the interior to the exterior.The size of spinel phase in low chromium vanadium slag is larger than the other vanadium slags with higher chromium contents.The spinel phase of high-calcium and high-phosphorus vanadium slag is more dispersed.The strongest diffraction peak of vanadium spinel phase in the vanadium slag migrates to a higher diffraction angle,and(Fe_(0.6)Cr_(0.4))_(2)O_(3)is formed after calcification roasting as the chromium content increased.A large amount of Ca_(2)SiO_(4)is produced because excess Ca reacts with Si in high-calcium and high-phosphorus vanadium slag.The vanadium leaching rate reaches 88%in some vanadium slags.The chromium leaching rate is less than 5%in all vanadium slags.The silicon leaching rate of high-calcium and high-phosphorus vanadium slag is much higher than that of the other slags.The leaching rate of manganese is higher than 10%,and the leaching rates of iron and titanium are negligible.

Influence of Anthracite-to-Ilmenite-Ratio on Element Distribution in Titanium Slag Smelting in Large DC Furnaces

The distribution of titanium,carbon and associated elements(calcium,magnesium,silicon and aluminum)in a smelting process is studied by means of a chemical equilibrium calculation method for multiphase and multicomponent systems,and verified through comparison with production results.In particular,using the coexistence theory for titanium slag structures,the influence of the AIR(anthracite to ilmenite ratio)on the distribution of such elements is analyzed.The results show that the AIR can be adjusted to achieve a selective reduction of oxides in the melt.

Response of Element Distribution of Various Organs of Maize to Fertilizer Application

The effect of fertilizer application on biomass dry weight and element distribution of various organs of maize was investigated from the aspect of microscopic view to disclose the internal mechanism of fertilizer effect on crop. Five fertilizer treatments： no fertilizer （CK）, nitrogen phosphorus fertilizer （NP）, nitrogen potassium fertilizer （NK）, phosphorus potassium （PK）, and nitrogen phosphorus potassium fertilizer （NPK） were designed. Field experiment on the response of biomass dry weight and N, P, K, Cu, Zn, Fe, and Mn element distribution of stem, leaf and seed of maize （Zea mays L.） to different fertilizer treatments application was carried out. The results showed that dry weight and element content of various organs of maize were different. N content of various organs followed this order leaf〉 seed 〉 stem; P content of various organs was seed 〉 leaf〉 stem; K content was stem 〉 leaf〉 seed; and Fe content was leaf〉 stem 〉 seed. Fertilizer application reduced the differences of N, P, K, and Fe contents of various organs, and changed the size order of the dry weight and the Cu and Zn contents of leaf, seed and stem. Except for individual treatment, the response direction of N, P and Fe elements to fertilizer application was similar to Cu and Zn. The response of element content of various organs of maize to different fertilizer combinations was also different. The response extent of N, P and K major elements to fertilizer application was larger than microelement of Cu, Zn, Fe, and Mn; the response extent of stem and leaf was larger than seed; the response to NPK fertilizer treatment was bigger than NP, NK and PK. In the whole, response differences of element distribution to various fertilizer treatments were not remarkable. Besides, element distribution of various organs of maize was also influenced by the mutual effect of fertilizer varieties. The response direction and extent of various element distributions to different fertilizer treatments had both similarities and differences. Adjusting fertilizer application could change the biomass dry weight and element distribution of various organs of maize, thus promote the uptake and cycle of nutrient. This investigation could provide useful information for high production.

Carbide precipitation and element distribution in high Co-Ni secondary hardening steel

As the increasing need of the steels with both high strength and hydrogen embrittlement resistance ability, carbide precipitation and element distribution in high Co-Ni secondary hardening steel were concerned. Carbide precipitation and element distribution in M54 were observed using carbon replicas method. Both simulation and observation results showed that MC and M2C formed in the steel. MC was round particle, which would act as grain refiners. And MzC was needle-like phase, which would be remarkable strengthening phases. Nb and V were main metallic elements in MC phase. Mo and Cr were main metallic elements in MzC phase. W, Co, and Ni were probably mainly dissolved in the matrix. As the carbide precipitation in AerMetl00 was M2C, which had similar size and shape with M2C in M54, the tensile strength and yield strength of AerMetl00 and M54 were similar. Compared with traditional high Co-Ni secondary hardening steel, M54 had higher hydrogen embrittlement resistance ability, probably because of element W in the matrix.

Effects of Electromagnetic Continuous Casting on Structures,Element Distributions and Mechanical Properties of Cu-Mg-Te-Y Alloys

New Cu-Mg-Te-Y alloys with high strength and high conductivity were prepared by electromagnetic continuous casting（EMCC）and direct chill casting（DC）.The structures,patterns of elements distributions and mechanical properties of the alloys were investigated.It was found that the equiaxed crystal zone was enlarged and the element Mg and Cu;Te phase were well-distributed by medium-frequency electromagnetic field during continuous casting method.Moreover,the defects and casting impurities were significantly reduced with the addition of electromagnetic,leading to the improvement of the mechanical properties.

Effects of Cerium on Alloy Elements Distribution in Ferrous Matrix Material

The effect of the addition of rare earths in Fe-based high chromium alloy powders on elements distribution in matrix materials and mechanical properties were studied. The results show that the addition of cerium can increase the chromium amount in carbonides and increase the micro-hardness after carbonization and the wear-resistant property of materials.

Alterations in Low-Z Elements Distribution in Heart Tissue after Treatments to Breast Cancer Using LEXRF Technique

Data from Global Cancer Statistics show that breast cancer (BC) is the most common type of cancer among women, leading the number of deaths caused by cancer. The developments in diagnosis and treatment techniques for the BC, including chemotherapy and/or radiotherapy, increased the survival rates for this type of cancer. One late complication induced by BC treatment is the cardiotoxicity. This term comprises different cardiotoxic side effects, which include blood pressure alterations, myocardial ischemia, congestive heart failure and other damages. This study aimed to evaluate the cardiac alterations induced by radiotherapy and chemotherapy, simulating a treatment for BC in Wistar rats. It is, therefore, important to understand the mechanisms involved in the cardiotoxicity, in order to prevent women from this late effect, when they undergo BC treatments. The major interests in this work are in Low atomic weight elements as Sodium, because it is strongly related to cardiomyocyte contraction;Magnesium, because it is important in the cardiac metabolism;and Iron, because BC treatment induced cardiotoxicity can be associated to the oxidative stress. Changes that occur in unhealthy tissues in case to cardiovascular damages can be better understood when elemental compounds and structures of healthy tissues are known. Low Energy X-ray Fluorescence (LEXRF) technique was used to obtain elemental maps of low Z-elements providing a semi-quantitative analysis of the tissues evaluated under different conditions. Through the technique LEXRF we obtained elemental and absorption maps. The results showed more damages when associating chemotherapy and radiotherapy in comparison to myocardium healthy. Those images taken together with light microscopy, X-ray absorption and phase contrast images, satisfactorily characterize the cardiac tissue for the first time in the literature, from the structural and morphological points of view. LEXRF was carried out at TwinMic beamline in the ELETTRA Synchrotron Fa-cility, at the beamline TwinMic, in Trieste, Italy.

Relationships between femoral strength evaluated by nonlinear finite element analysis and BMD,material distribution and geometric morphology

Precisely quantifying the strength of the proximal femur and accurately assessing hip fracture risk would enable those at high risk to be identified so that preventive interventions could be taken.Development of better measures of femoral strength using the clinically

An investigation of cellular distribution of manganese in hyperaccumlator plant Phytolacca acinosa Roxb. using SRXRF analysis

Phytolacca acinosa Roxb. （P acinosa） is a recently discovered manganese hyperaccumulator plant from southern China. It is a good candidate for phytoremediation of manganese（Mn） polluted soil for its high biomass and fast growth. Knowledge of the tissue localization and identification of heavy metals can provide essential information on metal toxicity and bioaccumulation mechanisms. Synchrotron radiation X-ray fluorescence spectroscopy （SRXRF） microprobe was used in this study to investigate the cellular distributions of Mn and other elements in root, stem, leaf, petiole and midrib of P. acinosa. The highest Mn content was found in the vascular tissues of root, stem, petiole and midrib. Cortex in root played a key role in Mn absorption and Mn was limited in the vascular bundle during the process of transportation in stem. Moreover, Mn content in leaf epidermis was higher than that in mesophyll, which suggested that the sequestration of Mn in leaf epidermis might be one of the detoxification mechanisms of P. acinosa. The significance of other elemental （such as P, S, K, Ca, Fe, Zn and Cu） distribution patterns and the correlation with Mn were also discussed.

Late Paleozoic Element Migration and Accumulation under Intracontinental Sinistral Strike-slip Faulting in the West Junggar Orogenic Belt, NW China

The migration,accumulation and dispersion of elements caused by tectonic dynamics have always been a focus of attention,and become the basis of tectono-geochemistry.However,the effects of faulting,especially strike-slip faulting,on the adjustment of geochemical element distribution,are still not clear.In this paper,we select the West Junggar Orogenic Belt(WJOB),NW China,as a case study to test the migration behavior of elements under tectonic dynamics.The WJOB is dominated by NE-trending large-scale sinistral strike-slip faults such as the Darabut Fault,the Mayile Fault,and the Baerluke Fault,which formed during the intracontinental adjustment under N-S compression during ocean-continental conversion in the Late Paleozoic.Geochemical maps of 13 elements,Al,W,Sn,Mo,Cu,Pb,Zn,As,Sb,Hg,Fe,Ni,and Au,are analyzed for the effects of faulting and folding on element distribution at the regional scale.The results show that the element distribution in the WJOB is controlled mainly by two mechanisms during tectonic deformation:first is the material transporting mechanism,where the movement of geological units is consistent with the direction of tectonic movement;second is the diffusion mechanism,especially by tectonic pressure dissolution driven by tectonic dynamics,where the migration of elements is approximately perpendicular or opposite to the direction of tectonic movement.We conclude that the adjustment of element distributions has been determined by the combined actions of transporting and diffusion mechanisms,and that the diffusion mechanism plays an important role in the formation of geochemical Au blocks in the WJOB.

Carbon,Nitrogen,and Sulfur Contents in Marine Phytoplankton Cells and Biomass Conversion

In this study,we isolated and cultured phytoplankton along the coast of China and measured the cellular carbon,nitrogen,and sulfur contents under four temperatures.The results showed that the contents of the cellular elements varied widely among different phytoplankton.We found that temperature is one of the important factors affecting the carbon,nitrogen,and sulfur contents in phytoplankton cells;however,the degree of influence of temperature is different for different kinds of phytoplankton.By measuring the nitrogen content in cells,we found that the C:N ratio indirectly measured in the experiment fluctuated in the range of 3.50-8.97,and the average C:N ratio was 5.52.In this experiment,we accurately measured the cell elemental contents at different temperatures and transformed the cell count results into carbon,nitrogen,and sulfur contents to express the biomass.This method ensures that the contribution of species that are small in number but with a large cell volume in biomass is considered.Moreover,this method comprehensively considers the interspecific differences of species and the uneven distribution of elements in phytoplankton cells,which is of significance in the estimation of marine carbon and nitrogen budget.The distribution of nitrogen content in marine phytoplankton can well indicate the marine eutrophication caused by human activities.Climate change can affect the community structure and element composition of marine phytoplankton,meanwhile marine carbon and nitrogen element can regulate the climate to a certain extent.

Geochemical, Sedimentological and Mineralogical Characterization of Surficial Sediments in Eynak Marsh (North of Iran)

A multidisciplinary study of the sedimentology, geochemistry and mineralogy has been conducted to understand the linkage between marsh and alluvial sediments and also their potential sources in Eynak marsh, North of Iran. The influence of the upstream potential sources on recent sediment geochemistry has been discussed based on geochemical, sedimentological and mineralogical results. A spatial grain size distribution study was carried out to investigate the hydrodynamic and deposition system of the marsh. So, the surficial sediment sampling was carried out to describe the sedimentological parameters and elemental geochemistry of sediments in Eynak marsh. Mineralogical complexes are mainly made up of felsic minerals such as quartz, calcite, feldspar, pyrite, mica, and clay minerals (in very low values) indicated by high amounts of Al, Ca, and Ni. As expected, the mineralogy of sediments is controlled mainly by the rock formations. Also sediment textures are controlled by the hydrodynamic condition in the marsh. So its distribution has been influenced by distance from the entrance sediments to Eynak marsh. The results showed that there are no enrichments related to fine grain sediment distributions. An association of Al with the trace elements such as Sc, Y, La, Ce, and Zr indicates that their distributions are mainly controlled by the felsic rocks in the upstream. On the other side, due to the waste water entrance to the marsh, Ni and Pb concentration could be under the effects of anthropogenic activities around the marsh. Results represented high values for Mn concentration (min 462, max 1784 and average 1037 ppm) and it showed a significant correlation with Ca, Sr, and Mg. A redox habitat and constantly calm hydrodynamic circumstance in the study area, likely cause high concentration of Ca, Sr, and Mg, and Mn. And they are representing negative correlations with some elements such as Al, Be, Fe, K, and Na.

Chemical composition of aerosols in winter/spring in Beijing

In 1999 aerosol samples were collected by cascade at Meteorological Tower in Beijing. The 12 group aerosol samples obtained were analyzed using PIXE method, which resulted in 20 elemental concentrations and size distribution of elemental concentrations. From the observation, the elemental concentrations, size distribution of elemental concentrations and their variations are analyzed. It shows that concentrations of the most elements in aerosols increase greatly compared with those in the past except that the concentrations of V, K, Sr, and the source of aerosols has changed greatly in the past decade. Fine mode aerosols increase more rapidly in the past decade, which may be due to the contribution of coal combustion and automobile exhaust. Pb content in aerosol is much higher than that at the beginning of 1980s, and has a decreasing trend in recent years because of using non leaded gasoline.

Size distribution of chemical elements and their source apportionment in ambient coarse, fine, and ultrafine particles in Shanghai urban summer atmosphere

Ambient coarse particles （diameter 1.8-10 μm）, fine particles （diameter 0.1-1.8 μm）, and ultrafine particles （diameter 〈 0.1 μm） in the atmosphere of the city of Shanghai were sampled during the summer of 2008 （from Aug 27 to Sep 08）. Microscopic characterization of the particles was investigated by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy （SEM/EDX）. Mass concentrations of Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Rb, Sr, and Pb in the size-resolved particles were quantified by using synchrotron radiation X-ray fluorescence （SRXRF）. Source apportionment of the chemical elements was analyzed by means of an enrichment factor method. Our results showed that the average mass concentrations of coarse particles, fine particles and ultrafine particles in the summer air were 9.38 ± 2.18, 8.82 ± 3.52, and 2.02 ± 0.41 μg/m3, respectively. The mass percentage of the fine particles accounted for 51.47% in the total mass of PM10, indicating that fine particles are the major component in the Shanghai ambient particles. SEM/EDX results showed that the coarse particles were dominated by minerals, fine particles by soot aggregates and fly ashes, and ultrafine particles by soot particles and unidentified particles. SRXRF results demonstrated that crustal elements were mainly distributed in the coarse particles, while heavy metals were in higher proportions in the fine particles. Source apportionment revealed that Si, K, Ca, Fe, Mn, Rb, and Sr were from crustal sources, and S, Cl, Cu, Zn, As, Se, Br, and Pb from anthropogenic sources. Levels of P, V, Cr, and Ni in particles might be contributed from multi-sources, and need further investigation.

Elemental Quantitative Distribution and Statistical Analysis on Cross Section of Stainless Steel Sheet by Laser Ablation Inductively Coupled Plasma Mass Spectrometry

An innovative application of laser ablation inductively coupled plasma mass spectrometry （LA-ICP-MS） technique in illustrating elemental distributions on stainless steel sheets was presented. The technique proved to be a systematic and accurate ap- proach in producing visual images or maps of elemental distributions at cross-sectional surface of a stainless steel sheet. Two stain- less steel sheets served as research objects： 3 mm×l 300 mm hot-rolled stainless steel plate and 1 mm×l 260 mm cold-rolled plate. The cross-sectional surfaces of the two samples at 1/4 position along the width direction were scanned （raster area -44 mm2 and 11 mm2） with a focused laser beam （wavelength 213 nm, diameter of laser crater 100 μm, and laser power 1.6 mJ） in a laser abla- tion chamber. The laser ablation system was coupled to a quadrupole ICP-MS, which made the detection of ion intensities of 27A1＋, 44Ca＋, 47Ti-, 55Mn＋ and 56Fe＋ within an area of interest possible. One-dimensional （ID） content line distribution maps and two- dimensional （2D） contour maps for specific positions or areas were plotted to indicate the element distribution of a target area with high accuracy. Statistic method was used to analyze the acquired data by calculating median contents, maximum segregation, sta- tistic segregation and content-frequency distribution.

3D Modeling and Determination of Factors Responsible for Zinc-Lead Mineralization in the Mehdiabad Deposit,Central Iran,based on Statistical Analysis of Geochemical Data

Although the Mehdiabad zinc-lead deposit is one of the most well-known deposits in the central Iran structural zone,the genesis of the deposit remains controversial.The host rock of the ore is a dolomitic limestone of the Lower Cretaceous Taft Formation.In the two main orebodies of the deposit,which includes the Black Hill and East Ridge ore zones,the oxide and sulfide ores are observed at the surface and at depth,respectively.The elements Zn,Fe,Mn and Mg are more abundant in the East Ridge ore zone(in both sulfide and oxide ores),with Ba,Pb,Ag and Cu being more abundant in the Black Hill oxide ore.Based on the distribution of elements and their correlation with each other in these ore zones,the elements are divided into three general groups,that of terrigenous elements,chemically-deposited elements and oreforming(hydrothermally deposited)elements,a division that is supported by the results of factor analyses.The spatial distribution of elements is jointly affected by contact with host rocks,the boundary of oxide-sulfide ores and fault zones.The main factors governing the distribution of elements are the mechanical transfer of detrital sediments,chemical sedimentation,transfer by hydrothermal fluids,oxidation and surface dissolution,all of which affected the spatial distribution of elements.The ore-forming elements are mostly affected by hydrothermal fluids and oxidation.This study not only provides additional information about the genesis of the Mehdiabad deposit,but also could assist in the exploitation of ore and further exploration purposes.The results of this study can aid in the exploration and exploitation of the Mehdiabad deposit and similar deposits in the region.

Discrete element modeling of the effect of particle size distribution on the small strain stiffness of granular soils

Discrete element modeling was used to investigate the effect of particle size distribution on the small strain shear stiffness of granular soils and explore the fundamental mechanism controlling this small strain shear stiffness at the particle level. The results indicate that the mean particle size has a negligible effect on the small strain shear modulus. The observed increase of the shear modulus with increasing particle size is caused by a scale effect. It is suggested that the ratio of sample size to the mean particle size should be larger than 11.5 to avoid this possible scale effect. At the same confining pressure and void ratio, the small strain shear modulus decreases as the coefficient of uniformity of the soil increases. The Poisson＇s ratio decreases with decreasing void ratio and increasing confining pressure instead of being constant as is commonly assumed. Microscopic analyses indicate that the small strain shear stiffness and Poisson＇s ratio depend uniquely on the soil＇s coordination number.

SIMULATION OF THE SPATIAL DISTRIBUTION OF CLIMATIC ELEMENTS IN MOUNTAINOUS REGIONS

In this paper,an effective method of simulating the spatial distribution of climatic elements in mountainous areas by using the semi-empirical theory is presented.As an example,the spatial distributions of temperature, vapor pressure,relative humidity,wind speed and precipitation in the Jianyang region and the Shaxi basin of Fujian Province are computed with this method,and the simulated results are in good agreement with the observations.

Study of the circumstance influence on the elemental distribution in ancient animal bone using μ-XRF

Elemental analysis of archaeological bone plays an important role in the study of the dietary habits of ancient animals. The elemental characteristic of diagenetic skeletons depends on the surrounding circumstance. The study of environmental influence on the elemental concentration of ancient bone is significant. In this paper, the diagenetic influence on archaeological skeletons is analyzed by microbeam X-ray fluorescence （p.-XRF）. The results show that the enamel is an excellent barrier to the diagenesis and the element Sr in bone isn＇t susceptible to contamination from the buried environment.