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High-dose ascorbate confers tubular mitophagy responsible for septic acute kidney injury (AKI) amelioration, yet its biological roles in immune regulation remain poorly understood.

Background : Platelet distribution width (PDW) and PDW-to-platelet ratio (PPR) have been proven to be good prognostic indicators for many diseases. However, their prognostic values in severe burns have not been reported. Objective : To investigate the early time course of PDW and PPR in severe burn patients and investigate their prognostic values. Methods : This is a 16-year, single-center retrospective study of 590 severe burn patients. The complete blood count parameters on day 1, day 3 and day 7 postburn, including PDW and PPR, were collected. Receiver operating characteristic curves (ROC) analysis, multiple logistic regression analysis and Kaplan-Meier survival analysis were performed to evaluate the prognostic values of PDW and PPR in severe burn patients. Results : According to 120-day follow-up records, 96 patients were non-survivors and 494 patients were survivors. ROC and area under the curve (AUC) analysis showed that, for predicting 120-day prognosis, the AUC of PDW (0.782) and PPR (0.816) on day 3 was the highest, followed by the AUC of PDW (0.764) and PPR (0.750) on day 7. The ROC-AUC of PPR (0.816) on day 3 was very close to that of the ABSI score (0.818). Multiple logistic regression analysis showed that the PDW (P = 0.033 and P = 0.009) and PPR (P = 0.052 and P = 0.046) on day 3 and day 7 were all significantly independently positively associated with 120-day mortality. Kaplan-Meier survival analysis showed that high PDW and PPR were both significantly associated with a high 120-day mortality rate on day 3 and day 7. Conclusion : PDW and PPR on day 3 and day 7 were independent risk factors for 120-day mortality in severe burn patients. These objective and readily available prognostic indicators may be more clinically favored.

The microstructure, mechanical properties and flame resistance behavior of the AZ91−1Ce alloys with different Ca additions were firstly investigated. Then, the effect of processing parameters, including applied pressures and rotation speeds, on the microstructure and mechanical properties of the rheo-squeeze casting AZ91−1Ce−2Ca alloy was studied. The results indicate that with the increase of Ca content, the microstructure is refined and the flame resistance of the AZ91−1Ce−xCa alloys increases. But when the Ca content exceeds 1 wt.%, with the Ca content increasing, the mechanical properties of the AZ91−1Ce−xCa alloys reduce rapidly. For rheo-squeeze casting process, the increase of applied pressure and rotation speed can both bring about significant refinement in the microstructure of the AZ91−1Ce−2Ca alloy and reduction of the porosity, so the mechanical properties increase. Compared to conventional casting, the AZ91−1Ce alloy with the addition of 2 wt.% Ca by rheo-squeeze casting not only guarantees the oxidation resistance (801 °C), but also improves mechanical properties.

Influences of Sn and Y on the microstructure, mechanical properties, and corrosion behavior of as-cast Mg-5Li-3Al-2Zn (LAZ532) alloy were investigated. The addition of Sn and Y refines grains and results in the formation of Mg2Sn and Al2Y phases, thus improving the mechanical properties of alloy by second phase strengthening and grain refinement strengthening. As-cast LAZ532 alloy shows typical filiform corrosion morphology, and the addition of Sn and Y does not change the corrosion mode of alloy. As-cast LAZ532−0.8Sn-1.2Y alloy shows excellent mechanical properties with yield strength of 166.2 MPa, ultimate tensile strength of 228.6 MPa and elongation of 14.8 %, and exhibits the best corrosion resistance with the smallest corrosion current density and the lowest anodic dissolution rate.

The effects of Al/Zn ratio (mass ratio) on microstructure and mechanical properties of the Mg−8Li alloy were investigated. The results indicate that in the as-cast Mg−8Li−xAl−yZn (x+y=5) alloys (LAZ alloys), when the Al/Zn ratio is 1:4 and 2:3, the secondary phases are mainly AlLi and MgLiZn phases; when the Al/Zn ratio is 3:2 and 4:1, the secondary phases are mainly AlLi and MgLi2Al phases. The decomposition temperature of MgLiZn phase is about 300 °C and the decomposition temperatures of AlLi phase and MgLi2Al phase are higher (∼350 °C). Solid solution strengthening is the main factor for the improvement of strength of Mg−8Li−xAl−yZn alloys. The Mg−8Li−3Al−2Zn alloy after solution treatment at 350 °C for 4 h has the best comprehensive mechanical properties (yield strength of 272.5 MPa, ultimate tensile strength of 315.0 MPa and elongation of 3.4%) among the studied as-cast and solid solution treated Mg−8Li−xAl−yZn alloys.

Ceramic coating was prepared on cast Al−Cu−Li alloy by micro-arc oxidation (MAO) in a silicate electrolyte solution with additives including NaWO and NaOH. The effect of NaOH addition varying from 1 to 9 g/L on the microstructure and corrosion behavior of the coatings was investigated. The coating was characterized by XRD, XPS and SEM with respect to the composition and microstructures. The results show that NaOH promoted the formation of oxides in the reaction of MAO and contributed to the increase of layer thickness. Electrochemical tests (polarization curve and EIS) and mass loss test indicate that the corrosion resistance of the coated Al−Cu−Li alloy was improved with the increased addition of NaOH. Moreover, the results prove that the alumina coating formed in the electrolyte with 7 g/L NaOH showed the best corrosion resistance. The examination of the full immersion corrosion test presents the same result of corrosion resistance.

Many studies show a "obesity paradox", which seems to protect against death. Whether an obesity paradox space is present in severe burn patients remains a matter of great debate. Most research on the obesity paradox of burn injuries is classified by body mass index (BMI) rather than by age.To investigate whether the obesity paradox exists in severe burn patients stratified by age.Retrospective analysis was performed on 490 patients with severe burns who were ≥ 18 years of age and were admitted to Fujian Medical University Union Hospital from January 2005 to December 2020. Demographic and clinical characteristics were collected, including age, BMI, total body surface area (TBSA), presence of inhalation injury, abbreviated burn severity index (ABSI) score, diabetes comorbidities, hypertension comorbidities, and in-hospital mortality. The patients were divided into the younger group (18 ≤ age65 years) and the older group (age ≥ 65 years). The important variables of the two groups were compared. The predictive value of BMI stratified by age on in-hospital mortality was evaluated by binary logistic regression analysis and the Cochran's and Mantel-Haenszel statistics.A total of 490 patients were selected for this study, and were divided into the younger group (413) and the elderly group (77) according to their ages. In the younger group, logistic regression analyses indicated that high BMI remained significantly and independently associated with decreased in-hospital mortality (P = 0.021). That is, in-hospital mortality decreased by 17.8% when BMI increased by 1 kg/mIn this study of patients with severe burns, overweight and obesity had protective effect on burn injury in the younger group (18 ≤ age65 years), but not in the older group (age ≥ 65 years). Investigating the obesity paradox in burn patients needs to consider age differences. However, multicentre clinical trials are needed to verify the results.

Two new compounds, namely, arteordosin A (1) and arteordosin B (2), were isolated from the CHCl3 extract of Artemisia ordosica. This is the first report on the structure elucidation of arteordosin A (1) and arteordosin B (2) based on spectroscopic methods including electrospray ionization mass spectrometry, one-dimensional (1D) nuclear magnetic resonance spectroscopy (NMR) and 2D NMR techniques. Antioxidant activities of the compounds were measured for their radical scavenging capacity using 2,2-diphenyl-1-picrylhydrazyl. Compound 1 (IC50 of 1.01 mg mL−1) showed antioxidant activity similar to the standard reference ascorbic acid (IC50 of 0.98 mg mL−1) and is more active than compound 2 (IC50 of 1.87 mg mL−1). In conclusion, arteordosin A (1) and arteordosin B (2) may be used as potential antihyperlipidemic agent in routine clinical practice.

The as-cast Mg−8Li− x Zn− y Gd ( x =1, 2, 3, 4; y =1, 2; wt.%) alloys were prepared in a vacuum induction furnace and their microstructure and mechanical properties were investigated. The results show that the increase of Zn content results in the volume fraction of W -phase (Mg 3 Zn 3 Gd 2 ) increasing while that of Mg 3 Gd phase decreasing. The strength of Mg−8Li− x Zn−1Gd alloys is improved with the increase of Zn content, which is ascribed to the second phase strengthening of fine strip-like W -phase and the solid solution strengthening of Zn element. For Mg−8Li−4Zn− y Gd alloys, the increase of Gd content leads to the appearance of coarse and discontinuous net-like W -phase, which decreases the strength. The Mg−8Li−4Zn−1Gd alloy exhibits an optimum comprehensive performance with the yield strength, ultimate tensile strength and elongation of 154.7 MPa, 197.0 MPa and 12.4%, respectively. In addition, the aging behavior of the typical alloys was also investigated.

The effect of different refining processes on inclusions and mechanical properties of cast Al-2Li-2Cu-0.2Zr alloy was investigated, including two-stage hexachloroethane (C2Cl6) refining process, two-stage rotating gas bubbling refining process and two-stage composite refining process. It was found that the two-stage composite refining process, which combined C2Cl6 and rotating gas bubbling, can significantly improve the melt purity and mechanical properties of cast Al-2Li-2Cu-0.2Zr alloy. Compared to the unrefined alloy, the volume fraction of gas porosity defects and slag inclusions decreased from 1.47% to 0.12%, and the yield strength, ultimate tensile strength and elongation of as-quenched alloy increased from 113 MPa,179 MPa and 3.9% to 142 MPa, 293 MPa and 18.1%, respectively. C2Cl6 was first utilized to degas and remove large size slag inclusions before lithium addition, and then the rotating gas bubbling was utilized to do the further degassing and remove the suspended fine inclusions after lithium addition. The two-stage composite refining process can take advantage of two methods and get the remarkable refining effect.

Rapamycin is known to inhibit the mammalian target of rapamycin complex (mTORC)1 signaling pathway, but it is unable to effectively inhibit mTORC2, resulting in activation of protein kinase B in multiple myeloma (MM) cell lines. Additionally, certain studies have suggested that resveratrol has an effect on human MM cells, and that rapamycin in combination with resveratrol may be useful in cancer therapy. The present study aimed to investigate the combined treatment effect of resveratrol and rapamycin on the MM MM1.S cell line. The results demonstrated that combined treatment with rapamycin and resveratrol effectively inhibited cell viability in the MM1.S cell line through inhibition of the mTORC1 and mTORC2 signaling pathways, compared with resveratrol or rapamycin monotherapy. In addition, cyclin D1 levels were decreased and the activation of caspase-3 and poly (ADP-ribose) polymerase was increased. These results suggested that downregulation of the mTOR signaling cascades is likely to be a crucial mediator in the impairment of viability and the induction of apoptosis resulting from combined therapy with resveratrol and rapamycin in MM1.S cells.

Microstructure evolution and mechanical properties of the rheo-processed ADC12 alloy were investigated by means of optical microscopy, X-ray diffraction and scanning electron microscopy. Primary dendritic Al of rheo-casting (RC) and rheo-diecasting (RDC) ADC12 alloys are sheared off. The average size, as well as solid fraction of the primary Al increase with descending pouring temperature. The mechanical properties of alloys are strengthened by rheo-processing. Ultimate tensile strengths of RC samples increase with the decrease of the pouring temperature, and reach the maximum in the range from 580 to 600 °C. At pouring temperature of 595 °C, the RDC sample obtains the best ultimate tensile strength and elongation. Great reductions on porosity and primary Al globularization are crucial to the mechanical properties. Relationships of the primary Al size and yield stress are depicted with Hall–Petch equation.

Dry wear behavior of the rheo-casting Al–16Si–4Cu–0.5Mg alloy was investigated by micro-scratch and dry sliding wear tests. Analyses of the microstructure, scratch grooves, wear tracks, worn surfaces and wear debris of the alloy were carried out by optical microscope and scanning electron microscope. The microstructural analysis showed that via rheo-processing, the primary Si was refined and rounded, eutectics dispersed more homogenously, and even the skeleton AlFeMnSi phase was fragmented into facet shape. Micro-scratch test showed that the microstructural refinement resulted in better wear resistance. Dry sliding wear test revealed that the rheo-processed sample exhibit obviously superior wear resistance because of the microstructure improvement. The dominant mechanism in mild wear condition is abrasion, but it turned to adhesion and oxidation in high applied load and fast sliding velocity conditions.

Human milk fat-style structured triacylglycerols were produced from microalgal oil in a continuous microfluidic reactor packed with immobilized lipase for the first time. A remarkably high conversion efficiency was demonstrated in the microreactor with reaction time being reduced by 8 times, Michaelis constant decreased 10 times, the lipase reuse times increased 2.25-fold compared to those in a batch reactor. In addition, the content of palmitic acid at sn-2 position (89.0%) and polyunsaturated fatty acids at sn-1, 3 positions (81.3%) are slightly improved compared to the product in a batch reactor. The increase of melting points (1.7°C) and decrease of crystallizing point (3°C) implied higher quality product was produced using the microfluidic technology. The main cost can be reduced from $212.3 to $14.6 per batch with the microreactor. Overall, the microfluidic bioconversion technology is promising for modified functional lipids production allowing for cost-effective approach to produce high-value microalgal coproducts.

The primary phase evolution of ADC12 aluminum alloy rheo-processed by mechanical rotational barrel system was studied by differential scanning calorimetry (DSC), optical microscopy (OM) and scanning electron microscopy (SEM). The semisolid slurry analyses show that the solid fraction of ADC12 aluminum alloy increases from 0.38 to 0.43 while the roundness decreases from 0.45 to 0.38 with increasing the rotational speed from 30 to 120 r/min. When the pouring temperature decreases from 620 to 580 °C, the primary α (Al) morphology changes from spheroidal to rosette-like. Besides, the average particle size of primary phase and solid fraction increase with the decrease of pouring temperature. By rheo-diecasting process, the components with fine, spherical and uniformly distributed primary α (Al) particles were obtained, and the best microstructure was contained at the pouring temperature ranging from 595 to 605 °C. The rheo-processing feasibility of ADC12 aluminum alloy can be explained by the grains controlled growth theory, and the semisolid slurry obeys the Mullins–Sekerka criterion when solidifying in the high pressure die casting machine.

A dynamic model was developed using two back-propagation neural networks of the same structure, one for online training and the other for prediction, and proposed for continuous dynamic prediction of the time series of NPP operating parameters. The proposed prediction model was validated by predicting such time series of NPP operating parameters as coolant void fraction, water level in SG and pressurizer. Validation results indicated the proposed model could be used to achieve a stable prediction effect with high prediction accuracy for the prediction of fluctuating data.

The semi-solid slurry of AZ91D magnesium alloy was prepared by gas bubbling process. The effect of processing parameters, including gas flow rate, cooling rate and stirring end temperature, on microstructure of AZ91D semi-solid slurry was investigated. With increasing the gas flow rate from 0 to 5 L/min, the average size of primary α-Mg particles decreases from 119.1 to 77.2 μm and the average shape factor increases continuously from 0.1 to 0.596. The formation of non-dendritic primary α-Mg particles during gas bubbling is the result of combined effects of dendrite fragmentation and copious nucleation. With increasing the cooling rate from 3.6 to 14.6 °C/min, the average particle size of primary α-Mg phase decreases from 105.0 to 68.1 μm while the average shape factor peaks at 9.1 °C/min. Both high and low cooling rates can induce dendritic growth of primary α-Mg particles. Changing the stirring end temperature from 590 to 595 °C has little effect on the average size and shape factor of primary α-Mg particles in AZ91D semi-solid slurry. The insensitivity of semi-solid microstructures to the stirring end temperature is attributed to the sufficient quantity of primary particles formed in the melt.

The effect of complex melt-refining treatment (melt flux incorporating with rotating gas bubble stirring) on microstructure and mechanical behavior of the sand-cast Mg–10Gd–3Y–0.5Zr alloy was investigated. In addition, the melt purifying mechanism of the complex melt-refining treatment for the sand-cast alloy was discussed systematically. The results show that the new melt-refining method can significantly improve melt quality and mechanical behavior of the tested alloy, i.e., compared to the reference unpurified alloy, the volume fraction of inclusions decreased from 0.47% to 0.28%, the ultimate tensile strength and elongation for T6-treated alloy increased from 245 MPa and 0.7% to 312 MPa and 4.5%, respectively. Especially, combining 1% flux with rotating gas bubble stirring can get even better purifying effectiveness than conventional sole 2% flux purification; the use of melt flux decreased by 50% and significantly reduced environmental pollution.

Influence of the pouring temperature ranging from 680 to 780 °C on the solidification behavior, the microstructure and mechanical properties of the sand-cast Mg−10Gd−3Y−0.4Zr alloy was investigated. It was found that the nucleation undercooling of the α-Mg phase increased from 2.3 to 6.3 °C. The average α-Mg grain size increased from 44 to 71 μm, but then decreased to 46 μm. The morphology of the eutectic compound transformed from a continuous network into a discontinuous state and then subsequently into an island-like block. The volume fraction of β-Mg 24 RE 5 phase increased and its morphology transformed from particle into rod-like. The increase in pouring temperature increased the solute concentration. YS increased from 138 to 151 MPa, and UTS increased from 186 to 197 MPa. The alloy poured at 750 °C had optimal combining strength and ductility. The fracture surface mode transformed from quasi-cleavage crack into transgranular fracture, all plus the dimple-like fracture, with the micro-porosity and the re-oxidation inclusion as major defects. The average α-Mg grain size played a main role in the YS of sand-cast Mg−10Gd−3Y−0.4Zr alloy, besides other factors, i.e. micro-porosity, morphology of eutectic compounds, re-oxidation inclusion and solute concentration.

The effect of the cooling rate ranging from 1.4 °C/s to 3.5 °C/s on the solidification behavior of the sand-cast Mg–10Gd–3Y–0.4Zr alloy was studied by computer aided cooling curve analysis (CA-CCA). With the increase in cooling rate, the nucleation temperature (Tα,N) increases from 634.8 °C to 636.3 °C, the minimum temperature (Tα,Min) decreases from 631.9 °C to 630.7 °C, the nucleation undercooling (ΔTN) increases from 2.9 °C to 5.6 °C, the beginning temperature of the eutectic reaction (Teut,N) increases, the time of the eutectic reaction shortens, solidus temperature decreases from 546.0 °C to 541.4 °C, and solidification temperature range (ΔTS) increases by 6.1 °C. The increased nucleation rate () is supposed to be the main reason for the increased ΔTN. Increased value (Teut,N–Teut,G) and shortened time of the eutectic reaction cause the change in the volume fraction and morphology of the second phase.

Influence of heat treatment on the microstructures and mechanical properties of sand-cast Mg–4Y–2Nd–1Gd–0.4Zr magnesium alloy was investigated, and the tensile fracture mechanisms of the studied alloys under different conditions were also discussed. The results show that the optimum T4 and T6 heat treatment conditions for the as-cast Mg–4Y–2Nd–1Gd–0.4Zr alloy are 525 °C, 8 h and (525 °C, 8 h)+(225 °C, 16 h), respectively, with regard to the microstructure observation, DSC heating curve and mechanical properties. The hardness, yield strength, ultimate tensile strength and elongation of the Mg–4Y–2Nd–1Gd–0.4Zr alloy treated by optimum T6 heat treatment are HV91, 180 MPa, 297 MPa and 7.4%, respectively. Moreover, the Mg–4Y–2Nd–1Gd–0.4Zr alloys under different heat treatment conditions exhibit different tensile fracture modes.

The microstructures and mechanical properties of Mg–4.2Zn–1.5RE–0.7Zr alloy were investigated under different heat treatment conditions. The as-cast alloy consisted of α -Mg phase, T -phase and Mg 51 Zn 20 phase. After aging treatment (single-step (325 °C, 10 h) and two-step (325 °C, 4 h)+(175 °C, 14 h)), neither T -phase nor Mg 51 Zn 20 phase dissolved into the matrix and the coarsening of α -Mg phase was not significant. When peak-aged at 325 °C for 10 h, dense short rod-like β′ 1 phase precipitated in the matrix. Further ageing at 325 °C led to coarsening of β′ 1 phase and a decrease in number density. Alloy aged at 325 °C for 10 h achieved the highest yield strength (YS) and ultimate tensile strength (UTS) of 153.9 MPa and 247.0 MPa, which were increased by 48 MPa and 23 MPa from as-cast condition, respectively. While the elongation slightly decreased to 15.6%. Comparatively, the YS and UTS of alloy two-step aged by (325 °C, 4 h)+(175 °C, 14 h) showed little difference from those of single-step aged alloy, but with a lower elongation of 13.4%. In addition, the fracture surfaces of Mg–4.2Zn–1.5RE–0.7Zr alloy under different thermal conditions were mainly characterized by quasi-cleavage feature, but with differences in the details.

in this paper, we attempted to find an effective method to resolve multi-satellite observation scheduling problems. Firstly, an acyclic directed graph model for multi-satellite observation scheduling was constructed. Secondly, based on the graph model, we presented a novel hybrid ant colony optimization mixed with the iteration local search algorithm (ACO-ILS) to produce high quality schedules. At last, extensive experimental simulations demonstrated that the proposed ACO-ILS algorithm is very efficient.

Epstein-Barr virus (EBV) is a ubiquitous human oncovirus. Previous studies by us and others have indicated that pet dogs frequently encounter EBV or EBV-related viral infection. In this study, we explored whether EBV is involved in canine malignancies in dogs. EBV-specific BamHI W sequence was detected by polymerase chain reaction (PCR) in 10 of 12 canine tumor specimens, including 8 of 10 oral tumors. Using reverse transcription-PCR, gene expressions of latent membrane protein 1 (LMP 1) and BamHI H rightward reading frame 1 (BHRF1) were identified in 8 and 7 of 12 specimens, respectively. A novel LMP1 variant, T0905, was predominant in 5 canine tumor specimens and found to exist in EBV positive human BC-2 cells. Another LMP1 variant, T0902, was similar to human tumor variant JB7. The BHRF1 sequence identified from these canine tumors was identical to that of the B95-8 viral strain. LMP1 protein and EBV-encoded RNA (EBER) were detected by immunohistochemistry and fluorescent in situ hybridization, respectively, in several tumors, particularly in tumor nests of oral amelanotic melanomas. Furthermore, EBV-like virions adopting a herpesvirus egress pathway were detected in a canthal fibroblastic osteosarcoma and an oral amelanotic melanoma. In conclusion, we report the expressions of BHRF1 transcript (a viral anti-apoptotic protein), LMP1 (a viral oncoprotein) transcript and protein, EBER (a viral oncogenic RNA), and EBV-like virions in multiple canine tumors. The identity of BHRF1 and the resemblance of LMP1 variants between canine and human tumors indicate either a close evolutionary relationship between canine and human EBV, or the possibility of zoonotic transmission.

Influence of multi-cycle cryogenic treatment and tensile temperature on microstructure, mechanical properties and fracture mechanism of as-extruded Mg–10Gd–3Y–0.5Zr magnesium alloy was investigated. The results show that there have no significant changes in tensile properties of the tested alloy after 10 d in liquid nitrogen immersion or 10 cycles of high-low temperature treatment at all test temperatures. The room temperature ultimate tensile strength increases from 398 MPa to 417 MPa after 20 cycles of high-low temperature treatments. Compared with the room temperature, the tested alloys exhibit higher tensile properties at low temperatures. At −196 °C, the yield strength and ultimate tensile strength of the as-extruded-T5 Mg–10Gd–3Y–0.5Zr alloy are 349 MPa and 506 MPa, respectively, increasing by about 18% and 27%, respectively. The transgranular cleavage fracture mechanism is observed at room temperature, while at low temperatures both ductile fracture and cleavage fracture behaviors coexist.

The effects of cooling conditions on the microstructure of semi-solid AZ91 slurry produced via ultrasonic vibration process were investigated. AZ91 melts were subjected to ultrasonic vibration in different temperature ranges under different cooling rates. The results show that fine and spherical α-Mg particles are obtained under ultrasonic vibration at the nucleation stage, which is mainly attributed to the cavitation and acoustic streaming induced by the ultrasonic vibration. The reduction of lower limit of ultrasonic vibration temperature between the liquidus and solidus increases the solid volume fraction and average particle size. Increasing cooling rate increases the solid volume fraction and reduces the average shape factor of particles. The appropriate temperature range for ultrasonic vibration is from 605 °C to 595 °C or 590 °C, and the suitable cooling rate is 2-3 °C/min.

It is demonstrated experimentally that by using the mechanical rotational barrel processing system combined with high pressure die casting machine, the near-eutectic ADC12 alloy is possible to be rheo-processed. Microstructural characteristics of the semisolid slurry were investigated in different processing parameters. Microstructural evolution and solidification behavior of the semisolid slurry were discussed. The result shows that, the dendritic primary α-Al was sheared off by the vertical stress supplied by the rotational barrel. With a rotation speed of 30r/min and 40r/min, the semisolid slurry can achieve relatively high solid fraction. When the pouring temperature decreased from 620°C to 580°C, the morphology of the primary α-Al changed from spheroidal to rosette-like. Besides, the average grain size and solid fraction increased with the decreasing of pouring temperature. The solidification of the alloy melt during the rheo-diecasting process is composed of two distinct stages: the primary solidification and the secondary solidification. By using the rheo-diecasting process, the components with fine, spherical and uniformly distributed primary α-Al particles were successfully obtained. As the pouring temperature descended from 605°C to 585°C, the primary α-Al of the rheo-diecasting components had rounder morphology, larger average grain size and higher solid fraction.

The effects of inclusions on microstructure, mechanical property, corrosion behavior of Mg-10Gd-3Y (GW103K) alloys by unrefining, MgO ceramic filtering and JDMJ flux refining were investigated, respectively. The results indicate that with decreasing significantly the number and size grade of inclusions for the alloy refined with JDMJ flux, tensile strength and elongation increase; however, the yield strength is less than that of the alloy refined with MgO ceramic filter and unrefined alloy. With the decrease of the inclusions contents, the corrosion rate of the alloys quickly vary from 2.419 mg/(cm^2•d) to 1.265 mg/(cm^2•d). After inclusion content is reduced to 0. 385%, the corrosion rate has almost no changes. Finally, the relationship between the volume fraction of inclusions and service properties of GW103K alloy under different conditions are established quantitatively.

The effects of non-flux purification techniques on the mechanical properties and microstructure of AZ91 magnesium alloy were investigated by ICP, OM, XRD and SEM. The results show that Ar spraying with high flow rate could remove non-metallic inclusions and improve the mechanical properties of AZ91. The alloy obtains the best properties after argon spraying for 30 min at the melt temperature of 740 °C. The ceramic foam filter (CFF) could effectively improve the ultimate tensile strength and elongation of AZ91 alloy, especially the elongation, which increase with increasing pores per inch (ppi) and the thickness of CFF. Non-flux purification does not change the microstructure of AZ91 alloy. However, filtration has a certain effect on the fracture pattern of AZ91 alloy. To improve the mechanical properties effectively, both filtration and gas spraying should be utilized together.

In order to improve the purifying efficiency of RJ6 flux, 5% (mass fraction) GdCl 3 was introduced into the flux for refining Mg-10Gd-3Y-0.5Zr (GW103K) alloy. The results show that the RJ6 flux containing 5% GdCl 3 exhibits better adsorption ability to nonmetallic inclusions than the one without GdCl 3 . Moreover, the mechanical, corrosion properties and fluidity of the alloy refined with RJ6 flux and RJ6 flux containing 5% GdCl 3 were investigated, respectively. It is found that these properties are improved to a certain degree due to the removal of nonmetallic inclusions in the alloy. Thermodynamic analysis and surface tension experiments indicate that the main reason can be ascribed to the decrease of the surface tension of the flux with 5% GdCl 3 , which promotes the combination of flux and nonmetallic inclusions.

The effects of GdCl 3 in flux on the loss of Gd, microstructure, mechanical properties, and corrosion resistance of Mg-Gd-Y-Zr(GW103K) scraps were investigated by ICP, XRD, SEM and EDS. The results show that the loss of Gd in the alloy decreases with increasing GdCl 3 content in the flux, and the mechanism of GdCl 3 suppressing the loss of Gd was analyzed by thermodynamic theory. The optimal average mechanical properties could be obtained when the GdCl 3 content in the flux was 5% (mass fraction). Compared with the alloy only treated by JDMJ flux, the σ b and σ s of GW103K alloy were improved from 160.91 MPa and 133.88 MPa to 224.96 MPa and 157.91 MPa by 39.8% and 17.95%, respectively. Immersion test shows the corrosion rate of Mg-Gd-Y-Zr alloy refined by JDMJ+5.0% GdCl 3 flux was decreased dramatically from 0.762 mg/(cm 2 ·d) to 0.437 mg/(cm 2 ·d) by 42.7%. GdCl 3 has no effect on the fracture pattern of GW103K alloy.

The effects of CeCl3-containing fluxes on RE element loss, the high temperature mechanical properties, microstructure and corrosion properties of magnesium alloy containing RE have been studied. The results showed that a certain amount of CeCl3 in purification fluxes restrained the reaction between the Ce element and fluxes to decrease the loss of Ce in alloys. With the flux containing 9% CeCl3, the loss rate of alloy element Ce can be reduced from 26.9% to 3.4%, and the σb and δ of the alloys at 150°C counld be improved from 160.9MPa and 6.2% to 176.5MPa and 7.9% compared with that of conventional MgCl2-containing flux , respectively. Besides, the coarse β phase and rod-like RE phase were refined effectively by CeCl3-containing fluxes.

Recently application of magnesium alloys is expanded rapidly over the whole industry, especially in automotive and electronic industries. Most of magnesium alloy parts are produced by casting process and the quality control of castings is very important to reliability and durability of parts. Various properties of magnesium alloy castings are deteriorated by defects such as non-metallic inclusion and pore. 1–5) Especially control of non-metallic inclusion remained in magnesium alloy castings is very important because the possibility of entrance of non-metallic inclusion into melt is very high due to high reactivity of magnesium alloy melt with gas species above melt surface. There are various methods for removal of inclusions in melt including addition of flux, gas bubbling and filtration. 6–8) Formerly a method of addition of flux was mainly applied to remove inclusions from magnesium alloy melt. 9–11) But part of flux was entered into melt during pouring when flux could not be entirely removed as dross and/or sludge before pouring and the flux remained in casting degraded the quality of castings as harmful defect. So a method of bubbling of inert gas into melt has been paid attention as new method for removal of inclusions from melt, especially during steelmaking. 12–15) But studies on removal of inclusions from magnesium alloy melt by gas bubbling have not been carried out actively. In this study the effect of Ar gas bubbling on the removal of inclusions from AZ91D magnesium alloy melt is evaluated indirectly by measurement of tensile elongation of gravity mold castings of AZ91D magnesium alloy and analyzed qualitatively.