Structural and optical properties of nitrogen‐iron co‐doped titanium dioxide films prepared via sol‐gel dip‐coating: Effect of urea and iron nitrate concentration in the sol

In this study, nitrogen‐iron co‐doped titanium dioxide films were prepared via sol‐gel dip‐coating method using urea and iron nitrate as nitrogen and iron source, respectively. Nonmetal doping of TiO₂ have some disadvantages such as massive charge carrier recombination and losing the photo‐catalytic capability. Three different nitrogen‐iron co‐doped titanium dioxide sols with different urea and iron nitrate concentration were prepared. The resulting sols were homogeneous and transparent, and no precipitation was observed in any of them. It was observed that the film prepared with middle urea‐iron nitrate concentration sol got opaque in a short time after the dip‐coating process. All prepared films were characterized by X‐ray diffraction, X‐ray photoelectron spectroscopy, scanning electron microscopy, confocal microscopy and ultraviolet–visible (UV‐Vis) spectroscopy. It was found that the concentration of the urea and iron nitrate in the sol had an effect on the crystal structure, microstructure, surface morphology and optical properties of the resulting films. Samples with middle concentrations had amorphous structure and bigger particle size. It was seen that sample with higher iron amount has lower band‐gap. It is concluded that we can prepare transparent anatase, transparent amorphous and opaque amorphous titanium dioxide films by changing the urea and iron nitrate concentration in the sol.     

High pressure nitrogen gas alloying of Fe-Cr-Ni alloys

The concentration of nitrogen in molten Fe-Cr-Ni alloys has been substantially increased by melting under nitrogen overpressures. Total nitrogen concentrations exceeding 26 at % were obtained when melted under 200 MPa. Nitrogen is present in solidified alloys as interstitial nitrogen and as metal nitrides. The nitrogen concentration depends upon the alloy composition; nickel decreases the nitrogen concentration, whereas chromium increases the concentration. When iron and Fe-Ni alloys were melted under high nitrogen pressures they produced iron nitrides and when Fe-Cr-Ni alloys were melted they produced ON dendrites and precipitates.     

Nitrogen Addition to an O-1 Tool Steel

A new processing technique makes nitrogen alloying possible by adding nitrogen under elevated nitrogen pressure to prealloyed Fe-C ingots during continuous casting, producing a whole new class of precipitation-free, iron–carbon–nitrogen alloys. When both carbon and nitrogen bulk concentration levels exceeded 0.5 wt%, a duplex fcc-/(bcc-bct-) Fe microstructure resulted that is iron carbide- and nitride-free. With increasing carbon and nitrogen concentrations, there was an increase in the retained fcc-Fe phase. In cooling rate studies, increasing carbon and nitrogen concentrations shifted the knee of the fcc-Fe-to-bcc-Fe phase time–temperature–transformation (T–T–T) curve to longer times. Hardness, compression strength, and wear resistance increased with increasing carbon and nitrogen concentrations and were superior to iron–carbon alloys without the nitrogen addition.     

Erythropoietic agents, iron and hemoglobin—What happens beyond the trial setting: Observational data from the ANZDATA Registry

Background: The issues surrounding anemia management in patients receiving dialysis therapy are complex and widely debated. Although numerous trials have been published, clinical practice patterns may differ, particularly in the presence of uncertainty about the optimal management of anemia in this setting. Methods: We examined data from the Australia and New Zealand Dialysis and Transplant Registry (ANZDATA) regarding use of erythropoietic agents (EA), hemoglobin, and ferritin concentrations and transferrin saturation in 8476 prevalent dialysis patients in Australia and New Zealand during the 6 months preceding March 31, 2001. From this cross‐sectional survey, we examined the distribution of reported hemoglobin concentration, transferrin saturation, and ferritin concentration. Among hemodialysis patients, other predictors of hemoglobin examined included urea reduction ratio (URR), age, sex, and the presence of comorbidities. Results: In Australia, 87% of dialysis patients received an EA; in contrast, only 42% of New Zealand patients received an EA. Hemoglobin concentrations were significantly higher in Australia, where 16% of reported values were <100 g/L, compared to New Zealand where 37% reported values were <100 g/L. Transferrin saturation and serum ferritin concentrations were significantly correlated, but less strongly among those receiving EA than those not receiving these agents. Both transferrin saturation and serum ferritin were significantly and independently associated with hemoglobin concentration, as were age and sex. The association with ferritin was inverse: higher serum ferritin concentrations were associated with lower hemoglobin concentrations. There was poor agreement (κ = 0.15) between categories of low transferrin saturation (<20%) and low ferritin concentrations (<200 ng/mL). Among the Australian hemodialysis patients, there was no significant variation in Hb between categories where reported URR was ≥65%, whereas the group with a reported URR <65% had a significantly lower hemoglobin concentration. Conclusions: There was a wide variation in reported hemoglobin concentrations in this population. Potential contributing factors include variable patient responsiveness to EA and iron, differing regulations in Australia and New Zealand regarding government subsidy of EA, and the lack of consensus among physicians regarding hemoglobin target values. Although a cross‐sectional study cannot directly address the predictive value of iron indices for iron deficiency, it appears likely that transferrin and ferritin have different relationships with hemoglobin, and measurement of both may have greater clinical utility than either parameter alone.     

High-Pressure Processing and Characterization of Fe–High-C/N Alloys

A new process has been developed that results in (i) enhanced nitrogen addition to ferritic iron–carbon alloys and (ii) melt-casting in a single operation. This new processing technique enables Fe–C alloys to retain high nitrogen interstitial concentrations and to reduce significantly, and possibly eliminate, carbide formation. In this study two commercial-grade, steel alloys were cast under elevated nitrogen pressures, resulting in solid solution (austenite, ferrite, and martensite) high-carbon and high-nitrogen iron alloys that were, within detection limits, carbide- and nitride-free. These alloys were subsequently thermally processed to transform part of the retained austenite to martensite. The microstructure and mechanical properties of the alloys were studied as a function of carbon and nitrogen composition and as a function of thermal processing. The retain high nitrogen concentrations in these cast and processed iron–carbon alloys resulted in a substantial improvement in compression strengths.     

机械合金化Fe-Ni粉末的相结构

使用XRD和Moessbauer等方法，研究了在Ar气氛下机械合金化Fe—Ni粉末相结构的变化．结果表明，在机械合金化Fe64-Ni36粉末过程中，fcc相的数量随着球磨时间的增加先增加然后减少，与加乙醇球磨Fe64-Ni36的情形相同．当Ni的含量(原子分数)大于50％时，有fcc相、顺磁相和FeNi3形成，当Ni的含量低于50％时，bcc相的数量随着Ni含量减少而增加．Moessbauer谱的结果表明，因球磨时间或Fe、Ni比例的不同，Fe—Ni球磨粉末固溶体具有不同结构的原子配比。     

Partition of nitrogen in solidifying iron-carbon-silicon alloys

The partition of nitrogen between austenite and liquid iron was examined from the measurement of solubilities of nitrogen in these phases. On primary austenite crystallization, nitrogen was rejected into liquid iron at high temperatures and the partition behaviour was reversed at low temperatures. Silicon lowered the critical temperature where the partition behaviour of nitrogen changed. The partition of nitrogen between cementite and austenite was investigated by analysis of nitrogen in iron-carbon-silicon alloys, which were quenched in ice-water from an equilibrium state at subeutectic temperatures, and in the cementite extracted from them. Nitrogen was enriched in cementite for Fe-C-0.5 wt% Si alloy, similar to the case of pure Fe-C alloy. However, silicon reduced the degree of enrichment of nitrogen in cementite. By the use of the partition coefficients, the variations of nitrogen concentrations in the coexisting phases were evaluated during the solidification of cast irons. In the irons with lower carbon concentrations, the supersaturation of nitrogen in liquid iron attained during solidification increased with increasing silicon content, and silicon had a detrimental effect to promote the formation of nitrogen gas blowholes in low-carbon cast irons.     

Effect of experimentally induced reducing conditions on the mobility of arsenic from a mining soil

A method for estimating the release of contaminants from contaminated sites under reducing conditions is proposed. The ability of two chemical reducing agents, sodium ascorbate and sodium borohydride, to produce different redox environments in a gold mining soil contaminated with arsenic was investigated. Liquid-solid partitioning experiments were carried out in the presence of each of the reducing agents at different pH conditions. Both the effect of varying concentrations of the reducing agent and the effect of varying pH in the presence of a constant concentration of the reducing agent were studied. Concentrations of sodium ascorbate ranging from 0.0075 to 0.046 mol L(-1) and concentrations of sodium borohydride ranging from 0.0075 to 0.075 mol L(-1) were examined. The addition of varying concentrations of sodium borohydride provided greater reducing conditions (ranging from -500 to +140 mV versus NHE) than that obtained using sodium ascorbate (ranging from -7 to +345 mV versus NHE). The solubilization of arsenic and iron was significantly increased by the addition of sodium ascorbate for all concentrations examined and pH tested, compared to that obtained under oxidizing conditions (as much as three orders of magnitude and four orders of magnitude, respectively, for the addition of 0.046 mol L(-1) of sodium ascorbate). In contrast, the alkaline and highly reduced soil conditions obtained with sodium borohydride lead to a lower effect on arsenic solubilization (as much as one order of magnitude for pH values between ca. 7 and 10 and no effect for pH values between ca. 10 and 12) and no effect on iron solubilization for all concentrations examined and pH tested. At similar ORP-pH conditions the results of extraction for arsenic and iron were different for the two reagents used.     

Annular phase-matched dual-pump coherent anti-stokes Raman spectroscopy system for the simultaneous detection of nitrogen and methane

The concentration and pressure dependence of dual-pump coherent anti-Stokes Raman spectroscopy (CARS) signals from nitrogen and methane was investigated. CARS spectra were acquired from a gas cell at pressures of 0.007 to 2.24 MPa and methane concentrations of 0.5 to 50%. The square root of the methane signal intensity divided by the nitrogen signal intensity was found to have a near-linear dependence on methane concentration at all pressures investigated. The pressure dependence of this integrated intensity ratio decreased with increasing pressure and became negligible at the highest pressures tested. The shot-to-shot variation at concentrations determined from single-laser-shot measurements was less than 7%. Single-laser-shot CARS spectra of nitrogen and methane were obtained from the cylinder of a firing direct-injection natural gas engine.     

Fabrication of Lotus‐Structured Porous Iron by Unidirectional Solidification under Nitrogen Gas

A novel technique has been developed to fabricate lotus‐structured porous iron in which long cylindrical pores are aligned in one direction. The iron is melted and unidirectionally solidified in a pressurized gas mixture of nitrogen and argon. The process involves the dissolution of nitrogen in molten iron and the evolution of nitrogen pores due to the decrease in solubility of nitrogen during solidification. The porosity is controlled by adjusting the partial pressures of nitrogen and argon during melting and solidification. The nitrogen concentration in solid iron increases with increasing partial pressure of nitrogen at a given total pressure, leading to improvement of the mechanical properties of the porous iron.     

海洋鱼类弧菌病疫苗的制备--新型简易鳗弧菌(Vibrio anguillarum)培养基优化①

以一株从我国山东海域爆发弧菌病鲈鱼体内分离得到的病原菌鳗弧菌（Vibrio anguillarum MV425 O1型）为研究对象,对其实现高密度生产海洋鱼类弧菌病疫苗的培养基进行了优化研究。研究表明,碳源的NaCl造成的渗透压以及由发酵碳源和氮源导致的pH值变化是影响细胞正常生长的重要因素。海水中微量元素（除铁元素）对菌体生长的作用可被酵母浸出物补偿,高铁浓度有助于菌体生长。在确定显著影响因子的基础上,采用可旋转中心复合设计方案和响应面法进行了统计模型优化,优化设计有效地提高了细胞培养密度,实现在摇瓶条件下细胞干重5．8g/L和30L规模反应器中26．2g/L的较好的初步放大结果,并可替代海水培养基。     

High carbon–nitrogen iron alloys

A new processing technique produces high carbon–high nitrogen iron alloys by melting iron-carbon steels in a hot isostatic pressing (HIP) furnace with nitrogen as the pressurizing gas. Furnace cooling O-1 tool steel with enhanced nitrogen concentrations resulted in the retention of the austenite phase without formation of carbide and nitride precipitates. The duplex austenite/ferrite structure has enhanced hardness, strength, and wear resistance.     

The effect of particle size of iron powder on α to γ transformation in the nanostructured high nitrogen Fe-Cr-Mn-Mo stainless steel produced by mechanical alloying

In this study, the effect of particle size of iron powder on α to γ transformation in the nanostructured high nitrogen Fe-18Cr-10Mn-4Mo stainless steel, produced by mechanical alloying (MA) was investigated. For this purpose iron powders with two different particle sizes were used. MA was performed under nitrogen atmosphere, using a high-energy planetary ball mill. X-ray diffraction (XRD) patterns and nitrogen analysis revealed that by decreasing the iron mean particle size, a higher transformation rate is obtained due to increase in the rate of nitrogen absorption. Moreover, nitrogen solubility in both milled samples was increased noticeably by increasing the milling time. This is believed to be due to the increase of lattice defects and development of nanostructure through MA. Variations of grain size and internal lattice strain versus milling time, for both iron particle sizes, showed that the critical ferrite grain size for austenite nucleation is less than 10 nm.     

Hexavalent chromium reduction with scrap iron in continuous-flow system Part 1: effect of feed solution pH

The reduction of hexavalent chromium by scrap iron was investigated in continuous system, using long-term column experiments, for aqueous Cr(VI) solutions having low buffering capacities, over the pH range of 2.00-7.30. The results showed that the initial pH of Cr(VI) solution significantly affects the reduction capacity of scrap iron. The highest reduction capacity was determined to be 19.2 mg Cr(VI)/g scrap iron, at pH 2.50, and decreased with increasing the initial pH of Cr(VI) solution. A considerable decrease in scrap iron reduction capacity (25%) was also observed at pH 2.00, as compared to pH 2.50, due to the increased contribution of H(+) ions to the corrosion of scrap iron, which leads to a rapid decrease in time of the scrap iron volume. Over the pH range of 2.50-7.30, hexavalent chromium concentration increases slowly in time after its breakthrough in column effluent, until a steady-state concentration was observed; similarly, over the same pH range, the amount of solubilized Cr(III) in treated column effluent decreases in time, until a steady-state concentration was observed. The steady-state concentration in column effluent decreased for Cr(VI) and increased for Cr(III) with decreasing the initial pH of Cr(VI) solution. No steady-state Cr(VI) or Cr(III) concentrations in column effluent were observed at pH 2.00. Over the entire studied pH range, the amount of Fe(total) in treated solution increases as the initial pH of column influent is decreased; the results show also a continuously decrease in time of Fe(total) concentration, for a constant initial pH, due to a decrease in time of iron corrosion rate. Cr(III) concentration in column effluent also continuously decreased in time, for a constant initial pH, over the pH range of 2.50-7.30. This represents an advantage, because the amount of precipitant agent used to remove Fe(total) and Cr(III) from the column effluent will also decrease in time. The optimum pH for Cr(VI) reduction with scrap iron in continuous-flow system was established at the value of 2.50.     

Fabrication of nanostructures with different iron concentration by electron beam induced deposition with a mixture gas of iron carbonyl and ferrocene, and their magnetic properties

Electron beam induced deposition (EBID) with a mixture gas of iron carbonyl and ferrocene was carried out to fabricate nanostructures with different iron concentrations in a chamber of a scanning electron microscope. The iron concentration was controlled by changing the ratio of partial pressure of iron carbonyl and ferrocene. Electron holography observation revealed that the remanent magnetic flux density B _r values of the nanostructures were also changed depending on the iron concentration.     

The removal of arsenic(V) from acidic solutions

The residual concentrations of dissolved arsenic(V) in 1.5% sulphuric acid solutions treated with iron salts and alkaline earth metal compounds have been measured. The results are plotted on triangular composition diagrams covering the composition ranges As 0.2% to 1.2%, Fe 1.0% to 4.0%, alkaline earth metal 3.0% to 6.5%. The results indicate that ferrous iron and lime are the most effective in removing 99.9% of the arsenic over a wide composition range to give residual dissolved arsenic concentrations of ca. 0.5 ppm. Ferric iron is more effective when used in conjunction with mixed calcium and magnesium hydroxides than with lime alone. Ferric iron and dolomite offered the least effective treatment.The effect of lime particle size on the residual dissolved arsenic concentration following ferrous iron-lime treatment was studied. The optimum lime particle size range for arsenic removal was 50–100 μm.Leaching tests were carried out on samples of arsenic bearing sludge from the ferrous iron and lime treatment process mixed with sand chalk and clay soils. The presence of 5,000 ppm of acetic acid in the aqueous leachant did not appear to significantly affect the leaching test results and, after passage through contaminated and uncontaminated soils arsenic concentrations in the leachate were generally below 0.05 ppm. Ferrous iron and lime appeared to be suitable for treating the arsenic solutions and the resulting sludge seemed to be suitable for land disposal.     

Effect of Iron Particle Size and Concentration on Thermal Conductivity of Iron/Polystyrene Composites

The present study deals with the thermal conductivity of iron/polystyrene (PS) composites containing iron particles of different sizes: (5, 50, 150, and 250)  $\upmu \mathrm{m}$ , and with different iron concentrations: (0, 5, 10, 20 and 30) mass%. The effects of iron particle size and concentration on the thermal conductivity of iron/PS composites are investigated in the temperature range: (30 to 120)  $^{\circ }\mathrm{C}$ . It was found that the addition of ultrafine iron particles enhances the thermal conductivity of the composites more than that of larger (coarser) particles. The thermal conductivity also increases with increasing temperature and iron concentration. The glass transition temperature was found to increase with decreasing size of iron particles. A correlation between the observed electrical and thermal conductivities of the iron composites as a function of iron particle size is presented. Fitting of some theoretical models results in predictions of smaller values of the thermal conductivity than are the experimental values.     

Tailoring the stress-depth profile in thin films; the case of γ’-Fe4N1-x

Homogeneous γ’-Fe₄N_1-x thin films were produced by gas through-nitriding of iron thin films (thickness 800 nm) deposited onto Al₂O₃ substrates by Molecular Beam Epitaxy. The nitriding parameters were chosen such that the nitrogen concentration within the γ’ thin films was considerably lower (x ≈ 0.05) than the stoichiometric value (x = 0). X-ray diffraction stress analysis at constant penetration depths performed after the nitriding step revealed the presence of tensile stress parallel to the surface; the tensile stress was shown to be practically constant over the entire film thickness. For further nitriding treatments, the parameters were adjusted such that nitrogen enrichment occurred near the specimen surface. The depth-dependent nitrogen enrichment could be monitored by evaluating the strain-free lattice parameter of γ’ as a function of X-ray penetration depth and relating it to the nitrogen concentration employing a direct relation between lattice parameter and nitrogen concentration. The small compositional variations led to distinct characteristic stress-depth profiles. The stress changes non-monotonously with depth in the film as could be shown by non-destructive X-ray diffraction stress analysis at constant penetration depths. This work demonstrates that by a specific choice of a first and a subsequent nitriding treatment (employing different nitriding potentials and/or different temperatures for both treatments) controlled development of residual stress profiles is possible in thin iron-nitride surface layers.     

洒水控制对钢铁厂原料堆场逸散扬尘的影响

选定中国钢铁公司厂内3种不同的原料堆场(煤料、石料与铁矿),分别就其洒水控制前后进行逸散扬尘的采样分析并探讨其变化。使用滤纸匣采样器吊挂于不同高程来替代一般地面上的总悬浮颗粒物(TSP)高量采样器进行现场采样。结果显示:就原料堆场风蚀作用所致逸散扬尘量而言,洒水后的扬尘控制效率分别为煤料的34.42%、石料的48.62%以及铁矿的66.81%;得知洒水对于风蚀扬尘的控制以铁矿为最佳,其次为石料,而煤料则最低。而物理成分分析结果显示,洒水后煤料所含的黏土含量及含水量均较铁矿与石料为高。另外,由于其喷洒水源使用的是厂内再生水,有可能因再生水的成分造成洒水后的逸散扬尘组成分起到变化。针对再生水与扬尘进行离子成分分析,结果发现洒水后,煤料中水溶性离子浓度有明显上升趋势;石料除了Mg2+及Ca2+浓度变化不大外,其余亦有明显上升的趋势;铁矿则与煤料有类似的情形。证实了喷洒再生水对扬尘中离子浓度的上升产生一定程度的影响。     

Structural disorder of ball-milled,nanosized, Fe-doped SnO<Subscript>2</Subscript>: X-ray diffraction and Mössbauer spectroscopy characterization

Structural characterization of nanosized Fe-doped semiconducting oxide SnO₂ is reported. Samples of Sn_1?x Fe _x O_2?y (with x ranging from 0.11 to 0.33) were processed in a planetary ball mill, subsequently HCl-washed to eliminate metallic iron impurities introduced by the milling tools, and characterized by X-ray diffraction and Mössbauer spectroscopy. Results showed that Fe enters the host matrix randomly replacing Sn in octahedral sites regardless of iron concentration. It has been found the presence of oxygen deficient iron sites attributed to the stoichiometric unbalance of precursor materials used in the milling process. It is known that structural features like particle size and residual microstrain are highly affected by the milling process. Values of average particle sizes as calculated by Scherrer’s method alone decreased with increasing Fe concentration. This result was shown, by means of the Williamson-Hall correction method, to be misleading as a large degree of microstrain is expected for mechanically milled powders. In fact, corrected values of average particle sizes turned out to be reasonably homogeneous regardless of iron content and milling time with no consistent trend. Residual microstrain, on the other hand, was found to increase with iron content giving way to the conclusion that broadening of diffraction peaks are mostly due to increasing microstrain as a function of iron doping and milling time. Williamson-Hall analysis also showed a large degree of particle size inhomogeneity. Milling of undoped SnO₂ showed that this inhomogeneity is due mostly to doping as opposed to milling.