Abstract:In order to study the influence of coated sand thickness on casting residual stress and solidification cooling process，the casting residual stress of ZL205A aluminum alloy cylinder with different sand thickness was measured by drilling method，and the solidification curves were collected.The paper has carried out finite element simulation of coated sand casting processes for ZL205A aluminum alloy specimen by adopting Von Mises mold and Mohr-Coulomb mold.The results show that the residual stress of castings can be reduced by about 62%,when the sand thickness reaches 7 mm.The residual stress changes a little with the sustained increasing of sand thickness.To provide a reliable process reference，the relationship between sand thickness and solidification cooling rate，grain size and eutectic temperature was established by analyzing and comparing the temperature curve measured in coated sand casting process.The simulation results show that the calculated results of the two models are basically consistent with the experimental trend.But we also need to take into account the applicability of the two models under different sand thickness.

Abstract:With micro diamond powder and silica sol as raw materials，the diamond and vitrified grinding wheel were prepared by sol-gel in-situ method.The effect of dispersant and defoamer on the properties of mixed slurry and abrasives was studied.The results show that with 0.4% naphthalene based super plasticizer added，the dispersity and the fluidity of mixed slurry are good，and the viscosity reaches the minimum value.When the addition of silicone defoamer DD is 0.2%，the microstructure of the composite sintered body is uniform with the minimum porosity and the maximum bend strength.Compared with the grinding wheel without additives，the microstructure of grinding wheel with dispersant and defoamer is dense and uniform.The surface quality of cemented carbide grinded by the new designed wheel is better.No deep scratches were observed，and the surface roughness was 0.04 μm.

Abstract:The effect of extrusion temperatures on the microstructures and mechanical properties of Mg-3Zn-2.5Al-2.5Ca(ZAC333) alloy was investigated by metallograph,SEM,XRD and tensile tests.The results show that the average grain size of the as-cast alloy is 185 μm. Due to the dynamic recrystallization,the grain size of as-extruded alloys was reduced from 6.32 μm to 3.36 μm with the extrusion temperature decreasing from 623 K to 523 K.The second phase of semi-continuous Al2Ca and continuous Ca2Mg6Zn3 was broken,which distributed along the grain boundary in the as-cast ZAC333 alloy. Compared with as-cast alloy,the mechanical properties of as-extruded ZAC333 alloy were improved. The tensile and yield strength of as-extruded alloy increased from 176 to 292 MPa,264 to 334 MPa,respectively,while elongation decreased from 20% to 9%. The improvement of mechanical properties for ZAC333 alloy can be attributed to the couple effects of refined crystalline strengthening caused by dynamic recrystallization and dispersion strengthening for the refined second phases during hot extrusion.

Abstract:6N01 alloy and 7N01 alloy are two important lightweight structural materials for the application of high-speed railway body. The microstructure,hardness distribution and corrosion characteristics in a typical T-joint between T5-treated 6N01 alloy and T5-treated 7N01 alloy dissimilarly welded by metal-inert gas welding (MIG) was investigated by electron back-scattering diffraction (EBSD),optical microscopy,Vickers hardness test and accelerated corrosion test. The results showed that there were significant differences in the grain structures between the weld seam,fusion zone and heat-affected zones. The weld seam had an equiaxed grain structure and the fusion zone consisted of equiaxed grains and columnar grains. In the region near the weld seam,abnormal grain growth was observed in the 6N01 part,while in the 7N01 part only recovery and partial recrystallization happened. In the heat-affected zones of the 6N01 part,there was a hardness groove,namely softening zone,the hardness of which was lower than that of the weld seam. The softening zone is attributed to obvious coarsening of precipitates affected by the heat input during welding. An obvious decrease in hardness occurred only in the weld seam after corrosion. In addition,the corrosion attacks mainly happened in the weld seam and heat-affected zones.

Abstract:Effects of Ca addition (0.3％，0.6％ and 0.9mass%) on microstructure,mechanical properties and bio-corrosion resistance of the Mg-4Zn based alloys prepared by high strain-rate rolling were investigated by OM,SEM,tensile testing and etc. Ca can refine the dynamic recrystallization grains of the as-rolled alloys,increase the content and the size of the residual second phases,and thus improve the ultimate tensile strength and yield strength. The ultimate tensile strength and the yield strength of Mg-4Zn-0.9Ca are 300MPa and 278MPa respectively,about 12.4% and 68.5% higher than Mg-4Zn. However,corrosion resistance and residual tensile strength decrease with the increasing Ca content,resulting from the higher content and the bigger size of the residual second phases. The bio-corrosion of the Mg-4Zn alloy is uniform since the second phase particles are fine and homogenously distributed. The average corrosion rate immersed in 0.9% NaCl for 7 days is 0.80 mg/（cm2·d）and the residual tensile strength immersed in 0.9% NaCl for 7 and 15 days are 217 MPa and 205 MPa,respectively.

Abstract:Cemented carbide wires YG8 and ultrahigh-strength steel strips D6A were welded on the band saw blade by using CO2 laser.The typical microstructure of welding joints,the distribution of element,and influence of different bonding technologies on welding joints microstructure and mechanical properties were studied by using metalloscope,electron microscope(SEM),microhardness meter and electron(EPMA).The results showed that isometric increased,dendrite decreased in the weld center and isometric near the side of YG8 fusion boundary area became more fine with the increase of welding speed .The hardness of the welding joints every bonding technology was higher than parent metal.Moreover,the hardness of the bond area near the side of YG8 was higher than the welded zones.When the welding power was 3 960 W and the welding speed was 9 m/min,the property of the wedded joints was good,and the value of bending strength reached 349 MPa,which reached the requirements of double metal band saw blade welding.

Abstract:ZnO/g-C3N4 composite was prepared by one-step calcining.The microstructure and absorption property of the as-prepared samples were characterized by XRD，SEM，TEM，FT-TR，and UV-vis DRS.The results showed that ZnO particles distributed uniformly on the surface of g-C3N4，and the light absorption edge of the composite had an obvious red shift compared with pure ZnO.Photocatalytic degradation of methyl orange solution experiments was conducted to evaluate photocatalytic activities of the as-prepared samples.The results indicated that ZnO/g-C3N4 exhibited higher photocatalytic activity than pure ZnO and pure g-C3N4.The photocatalytic efficiency was 14 and 9 times as high as that of ZnO and g-C3N4，respectively.The photocatalytic performance of the composite got promoted mainly due to the formation of heterogeneous structure between ZnO and g-C3N4，which decreased recombination rate of photo-induced electron-hole pairs.Furthermore，the composite had wider photoabsorption region compared with pure ZnO，which increased utilization rate of solar energy.

Abstract:In order to study the effect of cementite morphology on the structure and properties of sub-structure of pearlite in SWRS82B steel,related heat treatment process was established:The sample was cooled to 300 ℃ at the cooling rate of 70,100,200 ℃/s and isothermal to 3~15 s after austenitized at 880 ℃ for 15 min.Then heated to isothermal at 550 ℃ for 1 min,the last was the rapid cooling to room temperature. The results of SEM and TEM observation and MTS tensile testing machine show that,when the supercooling time was 3 s,the cementite was fragmented by different degree from the whole lamellar with the increase of cooling rates. When the cooling rate was 200 ℃/s,the cementite was broken down in large area,and nanoscale cementite was found.The tensile strength decreased firstly and then increased,but the elongation increased continuously.When the cooling rate was 70 ℃/s,the tensile strength and elongation decreased with the increase of the supercooling time. The nanoscale cementite decrease with the extension of the supercooling time;while reached to 15 s,the low bainite began to appear.

Abstract:A powder injection moulding-like process for producing carbon nanotubes reinforced copper matrix composites was developed.The process is a promising low-cost and large scale technique for production of complex copper metal matrix nanometer composite.The result reveals that uniform dispersion of carbon nanotubes in copper matrix can be achieved by using polymer-based binder.It is found that debinding，sintering，hot rolling temperature and content of carbon nanotubes have significant effect on the microstructure and properties of composites.The composite with 1 w.t% carbon nanotubes exhibited the best mechanical performance.Furthermore，hot rolling approach plays important role not only for work-hardening effect，but also for uniform distribution of carbon nanotubes in matrix，resulting in significant improvement in density and hardness for composite.

Abstract:The dispersion of multi-wall carbon nanotubes (MWNTs) in epoxy resin was facilitated with the assistance of high shear dispersing emulsifier. The MWNTs/EP composites was manufactured using vacuum assisted resin transfer molding (VARTM) technology,and the conductive properties affected by the speed and time were studied. The results showed that the conductive properties of the composite increased at first and then decreased with the increasing high shear dispersing time or speed. A threshold was captured when the high shear dispersing was 30 min and speed was 22 000 r/min. The addition of 1.5% MWNTs (wt. %) can decrease the surface resistance of epoxy resin within 5 orders of magnitude. The effect of dispersion of MWNTs in EP was also verified by scanning electron microscopy (SEM).

Abstract:In this paper，super-hydrophobic polyaniline with hierarchical structure has been synthesized via a “soft template chemical oxidation” method with aniline as monomer，ammonium persulfate as oxidant in the solution of perfluorocaprylic acid (PFOA).The morphologies and structures of the polyaniline were further proved by SEM，FT-IR，XRD and UV-vis.When ［PFOA］ = 0.002 4 mol/L，［ANI］ = 0.022 mol/L，T =25 ℃，［APS］ = ［ANI］，the synthesized PANI was a sheet structure about tens of micrometers in length and 2~5 μm in width，in which the surface of sheet structure was composed of PANI fiber (about 1 μm in length with a diameter ca.100 nm).When ［ANI］= 0.044 mol/L，the synthesized PANI was a sheet structure of about 20 μm in length and 2~3 μm in width，in which the surface was covered with short thick irregular fibers.The water contact angles of both structures were 149° and 151°，respectively.These results demonstrate that the as-prepared PANIs exhibit excellent hydrophobic properties.

Abstract:This paper aims to evaluate the influence of surfactants on the property of binding chloride in cement paste. Three surfactants,i.e.,TEA-Lauryl sulfate (TD),sodium dodecyl benzene sulfonate (LAS) and dodecyl polyglucoside (APG) are chosen to represent as cationic,anionic and nonionic surfactants,respectively. The chloride binding was determined by using the isothermal adsorption. Meanwhile,the mechanism of the influence of surfactants on the property of binding chloride in cement paste was discussed through the results from X-ray powder diffractometer (XRD) and thermal gravity analysis (TG-DTG). It is found that TD increases the chloride binding,but LAS and APG reduce the chloride binding. Compared with LAS,DPG has a weaker influence on the chloride binding. Besides,the different additions of surfactants have the similar effect on the chloride binding. Microscopic test results showed that all the surfactants mainly affected the physical absorption of chloride ions onto the cement hydrates,and exerted a minor influence on the chemical combination of chloride ions. In addition,modified stern double-layer model on cement surface was established.

Abstract:Azo dye is a common pollutant，and many researchers focus on its treatment. In this study，the ultrasonic assisted ball milling technology was used to degradate the Congo red. With the combination of ultrasonic cavitation，effect of zero valence iron and mechanical chemistry，the hydroxyl radical concentration increased significantly in solution. Then，reaction speed was apparently accelerated under the oxidation of hydroxyl radical and the reaction of nano iron. Eventually，the removal rate of Congo red reached 99% within 2 minutes. Most of the organic matters were mineralized，and the removal rate of total carbon (TOC) reached 80% with 10 min. The degradation efficiency increased significantly and the degradation effect was more thorough under high concentration. It is a cost-effective，simple and environmental method. All these indicated the ultrasonic assisted ball milling process is valuable to be applied to the degradation of azo dye wastewater.

Abstract:Carbon thermal reduction reactions of manganese ore powder by microwave heating and conventional heating were investigated. The effects of temperature,particle size and carbon-oxygen ratio on the reduction rates by microwave heating were studied by thermogravimetric analyzer. Afterwards,the dynamic equation of the carbothermal reduction process was obtained by fitting regression,and the rate-increasing factor Q which characterized the rate increase of microwave heating with respect to conventional heating was obtained. The results showed that the material heating rate augmented with the increase of carbon-oxygen ratio,and the heating rate was performed rapidly at the initial stage and then gradually decreased by microwave heating. The increase of both temperature and carbon-oxygen ratio could accelerate the reaction rate. The reaction rate was also significantly increased with the reduction of ore particle diameter till 150 mesh. Moreover,the weight loss of reduction reaction by microwave heating was much larger than that by conventional heating under the same temperature and heat preservation time. It indicated that microwave heating performed evident effect on speeding up the reaction rate at the low temperature and late stage.

Abstract:Different from the known setting and hardening properties of cementitious materials,this study focuses on the contact-hardening properties of nano- amorphous calcium silicate hydrate （C-S-H）. Two different types of C-S-H powders were used. The powders were compressed under 20~60 MPa for three minutes to produce compacts. Bulk density and compressive strength of the compacts as well as the microstructure of C-S-H before and after compaction were measured.The results show that nano C-S-H presents excellent contact-hardening cementitious properties. Lightweight and high strength compact can be produced by compression in several minutes. When the bulk density of the compact is about 800 kg/m3,compressive strength can be up to 20.0～30.5 MPa. According to the microstructure analysis,the distance of C-S-H particles is reduced during compaction because of the viscoelastic flow. Therefore,the particles become contact to each other,and attractive force between particles is formed. Furthermore,fragmentation and plastic deformation attributes to the compression pressure,leading to the formation of cohesion and adhesion structure. Consequently,the compressive strength of the compacts is greatly improved.

Abstract:The graphene oxide hydrosol was prepared by modification of the Hummer method. The palladium chloride was taken as the raw material to prepare palladium nitrate. By stiring，a uniformity and stable hydrosol was formed by mixing the graphene oxide hydrosol and palladium nitrate. Pd nanoparticles supported on the rGO were successfully synthesized after the process of freezing-drying and reducing by NaBH4. The morphology and structure of Pd/RGO nanohybrids were characterized by SEM and XRD. The electrocatalytic property for methanol oxidation and electrochemical stability was characterized by CV and CA. Compared with the Pd/rGO prepared by co-reduction，Pd/rGO prepared by sol-gel method has better electrocatalytic activity and electrochemical stability. After exploring the reaction conditions，the optimizing reaction conditions of preparation of Pd/rGO composites was：palladium mass fraction of 40%，urea dose of 100 mg.

Abstract:p(nBA/DEAEMA) nanoparticles of emulsion and polymeric cilia-like membranes were prepared. Two monomers of n-butyl acrylate (nBA) and 2-(diethylaminoethyl methacrylate) (DEAEMA) were polymerized by semi continuous emulsion polymerization method，and the cilia-like membranes were prepared by attaching a Velcro-like surface to partially coalesced films. Subsequently，the prepared materials were characterized by FT-IR，1HNMR，GPC，SEM，DSC combined with particle size analysis，static contact angle measurements and mechanical analysis. Finally，BECs from SD rats were used to characterize the biosecurity of the material. Correct structure of copolymer was also confirmed by FT-IR and 1HNMR. The particle size analysis of the copolymer emulsion was PDI 0.385 and Z-average was 46.48 nm，while Tg and Tf for copolymer was 33.2℃ and 47.7℃，respectively. The contact angle of polymeric films was 102.3° with water，and the surface free energy was 13.81 J·m2. Meanwhile，SEM photos showed the size of particles was 40 to 50 nm，and the height of cilia-like layer was about 5 to 10 μm. The biosecurity of this material was eventually verified by cell experiments. The copolymer cilia-like membranes can be used as a surface modification material for artificial trachea.

Abstract:A recombinant protein expression vector pET15b-R9-FOXM1(1-234aa) was constructed and transformed to E. coli in order to generate a strain expressing R9-FOXM1(1-234aa). The recombinant protein R9-FOXM1 (1-234aa) (R9-FOXM1(1-234aa)) was isolated at a large scale through His-tag affinity chromatography. The purity of the purified protein reached 90%. Moreover, MTT assay was used to test the effect of R9-FOXM1(1-234aa) on cells, and the test results showed that R9-FOXM1(1-234aa) caused the cell death of different types of cancer cells with a half lethal dose around 2 mm。 The results also demonstrated that R9-FOXM1(1-234aa) suppressed the proliferation of cancer cells and may be considered as a potential angent for anti-cancer in the future.

Abstract:In order to increase the stability of magnetite nanoparticles (MNPs) in suspensions and enhance their transport in the porous media,carboxymethyl cellulose (CMC) was used to modify MNPs.Batch experiments were conducted to investigate the stability of bare MNPs and CMC-modified MNPs in the artificial groundwater (AGW).Influence of CMC on MNPs transport in the quartz sand was also studied by using 1-D column experiments.The increase of surface charge due to CMC modification inhibited agglomeration of MNPs,and thus increased the stability of MNPs in the CMC solution.Such effects also greatly promoted the transport of MNPs in the quartz sand.

Abstract:The removal efficiency of a Cd-resistant Aspergillus fumigatus under different concentrations of Cd in laboratory flask culture was studied,and the changes of glutathione (GSH) production in the strain were determined. The results showed that the removal rate of Cd was 55.5% when the concentration of Cd was 50 mg/L,and the concentration of GSH was 0.89 μmol/mg. The comparison of Cd removal efficiency by Aspergillus fumigatus under different conditions showed that the optimal condition was 30 ℃,pH value of 5.0,add fluid volume of 120 mL,speed of 100 r/min,and inoculation amount of 0.4 mL (1.0×107 CFU/mL). Under the optimal condition,the removal rate of Cd was 29.8% higher than that under the initial condition,and the GSH content in the culture system was increased by 0.42 μmol/mg. The changes of glutathione peroxidase (GPX) and glutathione reductase (GR) indicated that Aspergillus fumigatus could remove the heavy metal Cd in the culture system under the optimized liquid growth conditions,GSH could promote the removal of cadmium,and its detoxification mechanism could be achieved by removing the oxidative substances produced by stress by GPX and GR in vivo.

Abstract:In order to master the regularities of dust movement with time and space in the screening workshop of asbestos concentrator and obtain the optimized parameters of dust removal by ventilation,screening workshop of No. 1 concentrator in Mangya Asbestos Mine was considered as the research background. Based on the theory of gas-solid two-phase flow,the discrete phase model (DPM) of computational fluid mechanics was used to simulate the dust concentration in screening workshop. By comparing with field measurement of dust concentration distribution,simulation results are essentially coincident with the measured data. The results indicate that the dust concentration near the screening equipment is higher,and the value decreases as the distance from the screening equipment increases. The dust concentration is lower under trap wall condition than the reflect,and the dust trapping effect is better. The dust settling effect is better when the inlet wind speed is about 0.6 m/s. When the exhaust dust cover is installed and the wind speed of main exhaust pipes is maintained at 14 m/s,the average dust-removal efficiency can reach 90%,and the asbestos fiber concentration can be controlled below 2.52 f/mL.

Abstract:Aiming at the characteristics of oil field sewage, the electrocoagualation (EC) process was used for the experimental study on preparation of oily waste water. The effects of electrode distance, initial pH and NaCl content on oil removal rate were analyzed, respectively, and the influence parameters were obtained. The flow field experiment was firstly carried out . Then, the solution was divided into representative of three layers in the vertical direction, while the changes of oil removal rate under different current density with time were examined, and the characteristic curves of the three layers with the oil removal rate were compared. The results showed that oil removal rate of A layer was the fastest and best, while the oil removal effect of B layer was worse than that of C layer. When electrolysis time was 4 min and current density was 150 A/m2, the oil removal effect of A layer accounted for 96.05% of total efficiency. Considering the average cost and oil removal rate of three layers, the overall treatment was the best in EC reactor when electrolysis time was 16 min and current density was 100 A/m2.

Abstract:Making alkaline ionic liquid ［Mmim］ DMP and using it as solvent by microwave heating，the effective removal of lignin in tobacco stems of reconstituted tobacco was studied. A rapid and accurate method for quantitative determination of liquid lignin by using UV spectrometry was established. The optimum technology for the removal of lignin in tobacco stems with the ionic liquids was determined by orthogonal experiment as follows: a maceration temperature of 80℃，a maceration time of 25 min and a solid /liquid ratio of 1∶15. In this process，the removal rate of lignin was 22.60%. The removal rate was about 5 times of that of water extraction. After extraction of tobacco stems by using ionic liquids，the fillers of fiber were removed heavily and the fiber profile was clearer，which were conducive to the pulping of the subsequent raw materials and the control of smoke quality.