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In the present work, the Mg/Al bimetallic composites were successfully prepared by the lost foam casting (LFC) process, and the characteristics and formation mechanism of the interface of the Mg/Al bimetallic composites were investigated. The results show that a uniform and compact metallurgical interface with an average thickness of about 1400 μm was formed between magnesium alloy and aluminum alloy. The interface layer of the Mg/Al bimetallic composites was composed of three different reaction layers, namely the Al12Mg17+δ(Mg) eutectic layer adjacent to the magnesium matrix, the Al12Mg17+Mg2Si interlayer and the Al3Mg2+Mg2Si layer close to the aluminum matrix. The microhardnesses of the interface layer were remarkably higher than those of the magnesium and aluminum matrixes. The stress strength of the Mg/Al bimetallic composites was up to 47.67 MPa. The fractograph of the push out sample mainly showed a brittle fracture nature. The formation of the interface of the Mg/Al bimetallic composites was attributed to the fusion and diffusion bonding. With the variations of the concentrations of the different elements at the interface, the Al3Mg2 intermetallic phase first formed near to the aluminum matrix, and then the Al12Mg17 and Mg2Si successively generated toward the magnesium matrix, finally obtaining the interface layer of the Mg/Al bimetallic composites.

In this study, deep eutectic solvents (DESs) formed by choline chloride (ChCl) and three glycols−ethylene glycol (EG), 1,3-propanediol (PD) and 1,4-butanediol (BD)−were investigated for NH3 absorption. The densities and viscosities of DESs at 298.2~358.2 K and 101.3 kPa were measured first, and fitted to the linear equation and Vogel−Fulcher−Tammann equation respectively. The solubilities of NH3 in DESs at 298.2~353.2 K and 0~250.0 kPa were then measured by a well-established dual-chamber method. The effects of temperatures, pressures and liquid compositions on NH3 solubilities were examined, and the NH3 solubilities of DESs were compared with those of other solvents reported in the literature. Finally, the solubilities of NH3 were fitted to the Krichevsky−Kasarnovsky equation to calculate the Henry's constants and partial molar volumes at infinite dilution of NH3 in DESs, as well as the enthalpy changes, Gibbs free energy changes and entropy changes for NH3 absorption process.

In order to improve the mechanical properties of A356 aluminum alloy in lost form casting (LFC), vibration and pressure were applied to solidification process of LFC, and the microstructures and the mechanical properties of the castings were compared with that of the castings in LFC without vibration and pressure. The results indicated that the grains of A356 alloy with vibration pressure in LFC became finer, and the dendrites decreased, and the equiaxed grains increased. At the same time, the porosities of the castings were significantly reduced. Compared with conventional LFC, the tensile strength, elongation, and hardness of A356 alloy with vibration pressure in LFC were all increased by 10% or above.

The mixture powder of Cr, Ni, Mo and Cu were deposited evenly on a ductile iron with ferrite matrix and treated by plasma transferred arc (PTA). The microstructure and hardness distribution of the PTA-alloyed layers were investigated by using scanning electron microscope (SEM) equipped with energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and microhardness tester, respectively. Results show that the cross-section consists of four regions: alloyed zone, melted zone, heat affected zone and unaffected substrate. The maximum microhardness of PTA-alloyed sample is measured to be as high as 1077 HV0.2, which is approximately 4.4 times higher than that of substrate. The improvement is attributed to the formation of mixed hard-phases such as Cr7C3, C23C6, martensite, cementite under nonequilibrium solidification, and the solution strengthening by the alloying elements as well as grain refining via the rapid cooling.

As cast AZ91D and AZ91D+1·0 wt-%Y magnesium alloy were prepared by the lost foam casting process and then treated by solution and aging treatment. The effects of Y on the microstructure and mechanical properties of heat treated AZ91D magnesium alloy were investigated. The results show that the addition of Y to AZ91D alloy formed the Al2Y phase, which still existed after solution treatment. During the aging treatment process, the rate of β-Mg17Al12 phase precipitating in AZ91D+1·0 wt-%Y alloy was much slower than in AZ91D alloy because the formation of Al2Y phase led to the depletion of Al atoms. The addition of Y was thus claimed to play a key role in delaying the age hardening peak on AZ91D alloy.

In this study, three dimensional structures are fabricated by a self-developed three dimensional printing machine with eight different particle size distribution scrubbed silica sand. In order to evaluate particle size distribution effect on the properties of sand mold, the physical and mechanism properties of printed specimens, including weight, gas evolution, air permeability, tensile strength and compressive strength, were measured. The mechanism of effect was analyzed and studied. The results show that the printed specimens from the 80-140 mesh sand powder have the best comprehensive properties. Both wider and narrower particle size distribution adversely affects the properties of printed specimens.

The effects of Cu addition on microstructure, mechanical properties and damping capacity of Mg-3%Ni based alloy were investigated by using tensile tests, X-ray diffraction, scanning electron microscope and dynamic mechanical analyzer. The results show that Cu addition could reduce the size of -Mg dendrites and a new binary phase Mg2Cu can be identified, which mostly distributes among the inter-dendrites in the form of typical lamellar-like eutectic microstructure and improve the mechanical properties. In low strain amplitude, with the increase of Cu addition, the damping capacities of Cu contained alloys change little, while in high strain range, the internal friction values decrease gradually with the grain refinement and increasing content of eutectic phase.

The influence of Y on the microstructure and damping capacity of AZ91D based alloys was investigated by optical microscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy and dynamic mechanical analysis. The results show that, with increasing Y content, the grain size of α-Mg matrix decreases tremendously and the distribution of β-Mg17Al12 phase is transformed from discontinuous network to fine particles. Meanwhile, a needle-shaped Al4MgY phase mainly distributing at the grain boundaries is identified. The damping capacity of the studied alloys shows sustained enhancement with increasing temperature. As to the strain dependent damping capacity, with the increase of Y content, the damping value of AZ91D alloy decreases gradually before Y content reaches to 0.5wt.%, and fluctuates when Y addition is between 0.5wt.%~0.9wt.%. G-L dislocation model was employed to explain the effects of parameters on damping capacity of magnesium alloy.

The vibration is superimposed to the filling process of aluminum and magnesium alloy in lost foam casting, and the flow lengths and the molten metal temperatures of the flow front are collected, and they compared with no-vibration. The results show that the vibration can significantly improve the filling capacity of the aluminum alloy, magnesium alloy in lost foam casting. Compared to the samples without vibration, the flow lengths of A356 alloy with vibration in lost foam casting increased by 33% and that of AZ91D alloy increased by 15%.The heat transfer of molten metal on the flow front was analyzed, and it indicates that the vibration energy extends the filling time of the molten metal on the flow front in lost foam casting.

Fluidity of ZL101 aluminium alloys in the low-pressure lost foam casting (LP-LFC) process has been investigated by altering various temperature variables. The experimental results indicate that the LP-LFC process had fine fluidity, and the pouring temperature was lower than conventional lost foam casting. The effect of the metal temperature on the fluidity is marginal in the LP-LFC process. Excessive pouring temperature not only aggrandizes energy consumption but also deteriorates porosity defect. The success of casting cooling fin demonstrates the advantages of LP-EPC process in producing high-complicated castings.

The microstructures and mechanical properties of Mg9AlZnGdY alloy after T6 heat treatment in lost foam casting (LFC) are compared with that of AZ91D magnesium alloy. The results show that the microstructures of Mg9AlZnGdY alloy after T6 heat treatment consist of the α-Mg solid solution, β-Mg17Al12 precipitation phase, a small amount of rod Al2Y and block Al2Gd phases, which are distributed over grain boundaries of the α-Mg phase. The thermal stability of Al2Y and Al2Gd phases offers the pinning effect on the grain boundary under high temperature, and therefore, the grain boundary sliding is eliminated and the high-temperature strength is increased. After the T6 heat treatment, the tensile strength of Mg9AlZnGdY alloy was 235MPa at room temperature, and 156MPa at 200°C. Compared with that of AZ91D alloy, the tensile strength was increased by 19.3% and 38.1% respectively.

A rotating gas bubble stirring technique with specially designed equipment has been developed for the production of light alloy semi-solid slurry. The equipment was specially designed to have temperature, rotation speed and gas flow rate control functions. An Al-Si aluminum alloy was applied as the experimental material. The results showed that large volume of semi-solid slurry could be achieved with the actual stirring temperature of 4 °C to 20 °C below the liquidus temperature of the alloy, and the rotation speed of 195 r/min, and the gas flow rate of 2 L/min. A strong convection and weak stirring effect which was induced by the rotating gas bubbles in the melt was founded responsible for the formation of the semi-solid slurry.

Mechanical vibration was introduced into the solidification in order to overcome the defects of coarse microstructure and low mechanical properties of the AZ91D magnesium alloy via lost foam casting（LFC）. The microstructure with fine uniform dendrite grains were achieved with mechanical vibration, which was mainly attributed to the cavitation and the melts flow induced by the mechanical vibration. The mechanical vibration has strong influence on the mechanical properties of AZ91D alloy. With application of mechanical vibration, the ultimate tensile strength and elongation of the AZ91D alloy increase 23% and 26%, resepectively.

The remnant binder on the surface of used sodium silicate sands can be dissolved in water. When frozen at low temperature, the hydrous remnant binder in moulding sands can become brittle, which is beneficial to strip remnant binder from the sand surface by means of mechanical force. A study of the 'freezing–mechanical' reclamation of used sodium silicate sands is reported. It is shown that 'freezing–mechanical' reclamation can be more effective than dry mechanical reclamation of used sands. The mechanical properties of remnant binder were found to change under freezing condition, which is propitious to the dry mechanical reclamation processing. The moisture content and freezing temperature of the used sands influenced reclamation effectiveness. The optimum moisture content was ∼10%, and the lower the freezing temperature, the more favourable the reclamation of the used sands.

A new technique of introducing gas bubbles during isothermal period of AZ31 magnesium to prepare semi-solid slurry has been reported. The effect of resting time after stirring on the microstructure of the slurry is discussed. Results show that the dendrites and liquid phase reduced, the non-dendritic grains grew up and became spheroidized. A fully grain-refined structure can be obtained with 60s resting time.

Three-dimensional printing has been used as a rapid freeform fabrication process to fabricate a wider range of green ceramic components with complex structures difficult to obtain using traditional ceramic fabrication process. In this study, calcia-based ceramic core composites were fabricated by three dimensional printing and sintering operation. The green bodies were printed using a CaO/TiO2 powder mixture as a precursor material and ethylene glycol as a binder. They were sintered at 1400-1500 °C for 2 h. The phases and microstructures of these samples were characterized by X-ray diffraction and scanning electron microscopy. The effect of TiO2 content and the sintering temperature on the density, hydration resistance and bending strength of the sintered bodies was investigated. It was found that increment of TiO2 content and sintering temperature would result in an increase of density of the sintered bodies and then increase of hydration resistance and bending strength.

To investigate the relationship between the polymorphism of site rs228648 in urotensin II gene and the genetic susceptibility to gestational diabetes mellitus in northern Chinese women.Genotyping was conducted to investigate the polymorphism of site rs228648 (G-A) in urotensin II gene among 70 unrelated gestational diabetes mellitus (GDM) subjects and 70 normal controls. DNA samples isolated from leucocyte of the control and study groups were analyzed for single-nucleotide polymorphisms of the urotensin II gene at positions rs228648 using polymerase chain reaction and restriction analysis.(1) The distribution of genotype frequencies of site rs228648 accorded with Hardy-Weinberg's equation law, being colony representative. (2) The frequency of G allele of site rs228648 was 70.7% in GDM group, significantly higher than that in the control group (57.9%, P0.05); and the frequency of A allele of site rs228648 was 29.3% in GDM group, significantly lower than that in the control group (42.1%, P0.05). There was no significant difference in the frequency of G/G genotype between GDM group and control group (52.9% vs 41.4%, P0.05). (3) Women in control group were more likely to be homozygous for the allele A of site rs228648 than women with GDM. The frequency of A/A genotype of rs228648 was negatively correlated with GDM group. By the logistic procedure, after adjustment by age and gestational weeks, the odds ratio was 0.312, and Wald Confidence Limites were 0.108 to 0.900 (P = 0.031).Urotensin II gene may contribute to the genetic susceptibility to gestational diabetes mellitus in northern Chinese population. G allele of site rs228648 is related to GDM possibly, and that homozygosis A of site rs228648 is likely to be an important protecting factor for GDM.

In China many women in labor are young primigravidas whose fear of labor pain leads them to request cesarean deliveries. While the rate of cesarean deliveries has reached 50% in many hospitals, less than 1% of women in labor are given neuraxial analgesia. The necessary equipment is seldom available in China and many physicians have misconceptions about the risks associated with neuraxial analgesia, which are low with the ultra-low-dosages used today. However, attitudes have begun to change. Meetings held in China have brought together Chinese physicians and world experts on the various epidural and combined spinal-epidural techniques. Thanks to the information and support provided at these meetings clinical trials were carried out, more than 5000 women benefited from labor analgesia, and publications appeared in Chinese journals. An effective, safe, and cost-effective way to provide analgesia to women in labor may slow the increase in cesarean delivery rates across China and improve women's health in general.