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ABSTRACTFlue gas circulation is an important method for energy conservation and pollutant emission reduction in iron ore sintering. In this paper the effects of flue gas recirculation ratio on sintering of different iron ores including haematite, magnetite and limonite were studied by illustrating the variation of sinter bed temperature, atmosphere and mineralisation characteristics of different types of iron ores induced by the circulation. It shows that the proper flue gas circulation ratios for haematite, magnetite and limonite are 37, 30 and 25%, respectively. For magnetite ore, preheating and high consumption of oxygen in combustion zone caused more silicate minerals and less acicular calcium ferrite, thereby lowering sinter tumbler strength. As for haematite ore, the rapid change of temperatures of combustion, melting and solidification zones leads to elevated combustion efficiency and increased formation of acicular calcium ferrite, which enhances the sinter strength. When using limonite ore as the main raw material, high oxygen consumption, lower maximum temperature of sintering bed, higher cooling rate and larger porosity of sinter are observed.

Flue gas circulation is an important method for energy conservation and pollutant emission reduction in iron ore sintering. In this paper the effects of flue gas recirculation ratio on sintering of different iron ores including haematite, magnetite and limonite were studied by illustrating the variation of sinter bed temperature, atmosphere and mineralisation characteristics of different types of iron ores induced by the circulation. It shows that the proper flue gas circulation ratios for haematite, magnetite and limonite are 37, 30 and 25%, respectively. For magnetite ore, preheating and high consumption of oxygen in combustion zone caused more silicate minerals and less acicular calcium ferrite, thereby lowering sinter tumbler strength. As for haematite ore, the rapid change of temperatures of combustion, melting and solidification zones leads to elevated combustion efficiency and increased formation of acicular calcium ferrite, which enhances the sinter strength. When using limonite ore as the main raw material, high oxygen consumption, lower maximum temperature of sintering bed, higher cooling rate and larger porosity of sinter are observed.

The catalytic reduction behaviours between NOxand CO in sinter zone were studied as using flue gas recirculation (FGR). Minerals in sinter can act as catalysts during NOxreduction. The catalytic activity of minerals has the order of calcium ferrite > kirschsteinite > fayalite. The catalytic procedure includes two steps: iron-bearing minerals are reduced to lower valence oxides by CO, and then NO is reduced to N2by lower valence oxides. Improving the generation amount of calcium ferrite, especially acicular-type silico-ferrite of calcium and aluminium (SFCA), contributes to significantly reinforcing the catalytic performance between NO and CO. As the basicity of sinter increases to 2.2, it enables to generate maximum amount of acicular-type SFCA which has larger specific surface areas, therefore facilitates decreasing NOxemission during FGR sintering.

The catalytic reduction behaviours between NOxand CO in sinter zone were studied as using flue gas recirculation (FGR). Minerals in sinter can act as catalysts during NOxreduction. The catalytic activity of minerals has the order of calcium ferrite?>?kirschsteinite?>?fayalite. The catalytic procedure includes two steps: iron-bearing minerals are reduced to lower valence oxides by CO, and then NO is reduced to N2by lower valence oxides. Improving the generation amount of calcium ferrite, especially acicular-type silico-ferrite of calcium and aluminium (SFCA), contributes to significantly reinforcing the catalytic performance between NO and CO. As the basicity of sinter increases to 2.2, it enables to generate maximum amount of acicular-type SFCA which has larger specific surface areas, therefore facilitates decreasing NOxemission during FGR sintering.

The structure of granules has been investigated and a model of granulation determined. The results show that a granule consists of an adhesive layer and a nucleus. Particles with diameter under 0.5 mm act as adhesive fines, while the remainders act as nuclei. By studying the influencing factors of granulation, two significant particle characteristics assessing granulation performance were determined. One is the relative proportion of adhesive fines and nucleus particles, and the other is the specific surface area of adhesive fines. The method of optimising granulation of sinter mixtures is proposed as follows: the proportion of adhesive fines should be 40–50 and the specific surface area should exceed 1000 cm2g−1, which contributes to achieving a better bed permeability, a faster sintering speed and higher productivity.

The structure of granules has been investigated and a model of granulation determined. The results show that a granule consists of an adhesive layer and a nucleus. Particles with diameter under 0.5 mm act as adhesive fines, while the remainders act as nuclei. By studying the influencing factors of granulation, two significant particle characteristics assessing granulation performance were determined. One is the relative proportion of adhesive fines and nucleus particles, and the other is the specific surface area of adhesive fines. The method of optimising granulation of sinter mixtures is proposed as follows: the proportion of adhesive fines should be 40–50% and the specific surface area should exceed 1000 cm2g-1, which contributes to achieving a better bed permeability, a faster sintering speed and higher productivity.

ß-SiAlON whiskers with uniform morphology were prepared using reaction sintering method under different conditions. The effect of preparing conditions on the morphology of ß-SiAlON whiskers was systematically studied by SEM, XRD, TEM and HRTEM. The results showed that single crystalline ß-SiAlON whiskers with uniform morphology were successfully fabricated at 1773 K for 6 h under flowing nitrogen atmosphere. The well synthesised whiskers were of several hundreds of nanometres in diameter and a few hundreds of micrometres in length. Although the morphology and its size distribution are mainly determined by the reaction temperature and holding time, they can also be tailored by controlling the reaction atmosphere. The ratio of staring materials has no significant influence on the morphology of ß-SiAlON whiskers. The growth of ß-SiAlON whiskers follows a vapour–solid mechanism, and the formation of the belt-like whiskers is attributed to an anisotropic growth at the early nucleation/growth stage.

We study the exciton polariton contribution to the Stokes shift in colloidal quantum dots (QDs). By detailed quantum mechanical description of light−matter interaction and temporal analysis of incident electromagnetic field across the QD using the finite-difference time-domain method, we have shown that the optical excitation of an exciton in the QD and its coupling with the excitation radiation (i.e., exciton polariton) induce strong variations in the dielectric constant of the QD which contribute significantly to the Stokes shift and cause modifications in the absorption spectrum that agrees well with experiments.

A first-principles study has been performed to evaluate the electronic and magnetic properties of the Zn1-xMnxO1-yNysystem. Doping Mn atoms introduces local magnetic moments, while doping N atoms introduces carriers. It is worth noting that intrinsic Mn-doped ZnO favors antiferromagnetic (AFM) ordering, and this cannot be changed by raising Mn ions concentration continuously. However, by the codoping N and Mn, it is possible to change the ground state from no-metallic AFM to half-metallic ferromagnetic (FM) and make ZnO as a dilute magnetic semiconductor. We have succeeded in describing the change (from AFM to FM) by using the magnetic interaction that is hole-mediated FM due to the hybridization between N 2pand Mn 3dstates. Furthermore, the most stable configurations are found to be -O-Mn-N-Mn-O-.Our results are in good agreement with other theoretical results that are additional holes carriers is one of the possible mechanisms.

Background: Steroidal saponins have long attracted scientific attention, due to their structural diversity and significant biological activities. For example, total steroidal saponins extracted from the rhizome of Paris polyphyllaSm. var. yunnanensis(TSSPs) constitute an effective treatment for abnormal uterine bleeding. Objective: To determine the active constituents in TSSPs and elucidate the mechanisms that underlie their in vivopharmacologic actions on hemostasis. Methods: Steroidal saponins were purified by chromatography, and their effects upon hemostasis and platelet function were evaluated by tail bleeding time in mice and rats, aggregometry, flow cytometry and Western blotting. Results: TSSPs promoted hemostasis in vivoand dose-dependently induced rat or human platelet aggregation in vitro. Using bioassay-guided separation, four known pennogenin glycosides with a spirostanol structure were identified as the active ingredients of TSSPs. A structure–activity assay showed that the aglycone and sugar moieties of pennogenin glycosides are both essential for their aggregatory activity. Their synergistic actions on platelet aggregation were observed with pennogenin glycosides and with other known platelet agonists, suggesting that these glycosides are platelet agonists. Aggregation in response to the pennogenin glycosides involved αIIbβ3activation, was inhibited by cAMP, was dependent upon extracellular calcium, secreted ADP and thromboxane synthesis, and was mediated by phosphatidylinositol-3-kinase. Conclusion: We identified pennogenin glycosides with a spirostanol structure as the active ingredients of Paris polyphyllaSm. var. yunnanensisin promoting hemostasis in vivo. Their mode of their action on platelets suggests that they represent a new type of platelet agonist.

A novel gel tape casting process has been developed by introducing sodium alginate into a conventional aqueous tape casting slurry. The process makes use of a binder system consisting of 1 wt-% sodium alginate and 20 vol.-% styrene acrylic latex to prepare the tape casting slurry. Sodium alginate can react with calcium iodate to form a three-dimensional network at room temperature, and with the ceramic particles held in this three-dimensional network, the slurry can be consolidated to form green tapes. This allows the need for the special drying procedure that is usually a critical step in tape casting to be avoided. Styrene acrylic latex was used to improve the flexibility of the green tapes. Compared with tapes obtained by conventional aqueous tape casting, more homogeneous microstructure was obtained by this process.

On the basis of an elasto-plastic analytical solution for laminating structure, making use of automatic dynamic increment nonlinear finite element analysis software ADINA [1], the self-strengthening research of a FRP (fiber reinforced pressure) vessel with metallic liner is presented in this paper. A self-strengthening pressure is determined to make the aluminum inner layer elastic deformation under hydrostatic pressure and to obtain the best ratio of the vessel’s volume and weight. Thus, the gas-tightness and fatigue strength of FRP vessel were improved. In addition, the influence of thermal load on the vessel was also calculated.

Numerous epidemiological studies, together with mounting evidence from studies in animals, point to a correlation between an adverse intrauterine environment and the early onset of cardiovascular and metabolic diseases later in life. We were the first to show that sheep exposed to dexamethasone (0.28 mg⋅kg-1⋅day-1 for only 2 days) at the end of the first month of pregnancy (PTG1), but not those exposed at the end of the second month of pregnancy (PTG2), had a higher basal mean arterial pressure (MAP) 19 months after birth. In the present study we report the MAP, cardiovascular haemodynamics and baroreflex sensitivity in these animals at 40 months of age. MAP in the PTG1 group was significantly higher than in the control group (91±1 mmHg and 81±1 mmHg respectively; P< 0.001) and also when compared with the PTG2 group (82±1 mmHg; P< 0.001). There was a significant increase in cardiac output in the PTG1 group compared with the control group (108±2 and 96±4 ml⋅min-1⋅kg-1 respectively; P< 0.05). The increase in cardiac output in the PTG1 group was due to an increase in stroke volume (1.82±0.08 ml⋅kg-1⋅beat-1, compared with 1.46±0.06 ml⋅kg-1⋅beat-1 in the control group; P< 0.05), but not in heart rate. In the hypertensive group of animals (PTG1), there was a rightward shift of the baroreflex curve. In group PTG2 (the normotensive group of animals), a lower gain was found before and during propranolol treatment. The decrease in gain of the baroreflex was not associated with changes in heart rate range, suggesting an impairment in the central processing of the baroreceptor signals. Thus sheep fetuses exposed to dexamethasone for only 2 days at the end of the first month of gestation have high blood pressure (dependent upon the increase in cardiac output) and a reset of the baroreflex at 40 months of age. Animals that have received prenatal dexamethasone closer to mid-gestation, although normotensive with normal cardiac output, showed an altered baroreceptor-heart rate response.

Glucocorticoid receptors were measured in the surgical specimens of 19 intracranial tumors and one brain contusion. None of the patients had received any steroid treatment prior to the operation. Preoperative computed tomography (CT) scans of these patients were evaluated with respect to attenuation values, contrast enhancement, volume of the tumor and edema, and the other characteristics. These various findings were plotted against the amount of glucocorticoid receptors. There was some correlation between the amount of receptor and attenuation as well as contrast enhancement of the tumor. No definite correlation between the volume of edema and/or size of the tumor and the amount of receptor was found in the material taken in its entirety. However, in two tumor groups, namely meningiomas with marked edema and circumscribed, discrete gliomas, a tendency toward a high amount of glucocorticoid receptors was observed. The positive correlation with contrast enhancement, reinforced by reports in the literature that contrast enhancement is affected by steroids, corroborates the theory that the steroid–receptor interaction plays an important role in the vascular permeability of tumors.

We report the comprehensive results obtained in our group and last few years for the shallow impurities in ultrapure silicon by use of photothermal ionization spectroscopy. The new results reported here include the discovery and investigation of new shallow impurity centers in Si, the detection for the compensation of different types of impurities, the accurate determination for the spin-orbit splitting ?. of valence band for Si, and the phonon duplicates and Fano resonance for the transitions of shallow impurities in Si. In addition it is also shown experimentally that the sensitivity of the photothermal ionization spectroscopy as used for detecting the concentration of shallow donors in Si can reach as high as 108 cm-3, much higher than that reported in the literatures up to date, and line width for the sharpest spectral lines in the spectrum is about 0.08 cm-1, that is, 10 µeV.

A monoclonal antibody against the rat liver glucocorticoid receptor was used in combination with rabbit antibodies against tyrosine hydroxylase, phenylethanolamine N-methyltransferase, and 5-hydroxytryptamine to demonstrate strong glucocorticoid receptor immunoreactivity in large numbers of central monoaminergic nerve cell bodies of the male rat. The receptor immunoreactivity was predominantly located in the nucleus, whereas the tyrosine hydroxylase, phenylethanolamine N-methyltransferase, and 5-hydroxytryptamine were detected mainly in the cytoplasm. The vast majority of the noradrenergic nerve cell bodies of groups A1-A7 and of the 5-hydroxytryptaminergic cell bodies of groups B1-B9 were found to contain strong glucocorticoid receptor immunoreactivity. The majority of the phenylethanolamine N-methyltransferase-immunoreactive nerve cells of the adrenergic cell groups C1-C3 and of the dorsal subnuclei of the nucleus tractus solitarius in the medulla oblongata were also strongly immunoreactive for glucocorticoid receptor. In the midbrain dopaminergic groups A8-A10, moderately (A8, A9) to strongly (A10) glucocorticoid receptor-immunoreactive cells were found, ranging from 40 to 75% of the total population. In the hypothalamic dopaminergic cell groups, all the cells of groups A12 and A14, as well as the majority of the dopaminergic cells of the zona incerta (A13), were found to contain moderate to strong glucocorticoid receptor immunoreactivity, but none of the large dopaminergic cells of the posterior hypothalamus (A11) showed such immunoreactivity.

To explore the pressure fluctuation characteristics of a low speed specific speed mixed flow pump caused by rotor-stator interaction, the unsteady flow was simulated with CFX for the whole flow passage of a mixed flow pump with a specific speed of 148.8. The structured mesh of the computation domain was generated with ICEM CFD and TurboGrid, and mesh-independent analysis was done in the design condition. Through the comparison with the experiment data, the reliability of the simulation was verified. In different locations of the impeller passage, monitoring points were set. With Fast Fourier Transform (FFT), the characteristic analysis on the pressure fluctuation in the impeller passage was done for three flow rate conditions (0.75Qd, Qd, 1.25Qd). The results show that the pressure fluctuation amplitude increases from the inlet to the outlet. And the maximum values in different flow rates exist near the hub of the outlet; The pressure fluctuation is small in the design condition, but the largest in the small flow rate condition, accompanied by the secondary dominant frequencies with large amplitudes; In the small flow rate condition and design condition, the dominant frequency varies from the inlet to the outlet because the combine action of the impeller and guide vane; while in the large flow rate condition, the pressure fluctuation in the whole impeller passage is affected significantly by the guide vane, and the domain frequency is 8 times the rotational frequency of impeller. In addition, the change of pressure fluctuation from the pressure surface to the suction surface in the off-design conditions is investigated, and the results demonstrates that the intensity of the pressure fluctuation in the impeller passage is closely related with the impeller as well as the distribution of the vorticity and the pressure.

Based on the assumption of tiny bubbly flow, the gas-liquid two-phase unsteady flow in a multiphase rotodynamic pump was numerically simulated with two-fluid model. The two-phase transport process and the evolution characteristic of the pump head were analyzed. In the working conditions, the liquid flow rate was constant, and the IGVF (inlet gas volume fraction) was 0.05, 0.15 and 0.25, respectively. The k o[?] based SST model was used for turbulence; the drag force and the added mass force were accounted for in the interfacial momentum transfer terms. Because the wrap angle of the blade was large, the hybrid mesh was adopted to guarantee high mesh quality. The simulation results demonstrate that two-fluid model can more reasonably capture the transport process than the homogeneous model; and the drag law should be corrected based on the mixture viscosity in high gas volume fraction conditions. If the liquid flow rate is constant, the increase of IGVF can raise the pressure in the inlet extended region, while the pressure in the outlet extended region will not be affected much, thus the pump head will go down. In addition, due to the fluctuation of gas volume fraction field, the pump head will also fluctuate around a stable value in the transport process.