Directional solidification of metal-gas eutectic and fabrication of regular porous metals

Directional solidification of metal-gas eutectic (Gasar) is a novel process for making regular porous metals.This process is based on a solid-gas eutectic reaction involving a gaseous medium and a metal or a ceramic phase, andallows an easy control of the porosity, such as its pore size, pore orientation and morphology in a wide range by properlyadjusting its melting and solidification conditions. The latest progress and our research work in this field are reviewed inthis paper.

Refinement of primary Si grains of A390 alloy slurry through serpentine channel pouring process

In this paper, the serpentine channel pouring process for preparing a semi-solid A390 alloy slurry and refining the primary Si grains of the A390 alloy, was used. The effects of the pouring temperature, the cooling water flow and the number of the curves on the size of the primary Si grains in the semi-solid A390 alloy slurry were investigated. The results show that the pouring temperature, the cooling water flow and the number of the curves have a major effect on the size and the distribution of primary Si grains. Under the experimental condition of the four-curve copper channel whose cooling water flow was 500 L·h-1 and the pouring temperature was 690 oC, the primary Si grains of the semi-solid A390 alloy slurry were refined to the greatest extent and the lath-like grains were changed into granular ones. Additionally, the equivalent grain diameter and the average shape factor of the primary Si grains of the satisfactory semi-solid A390 alloy slurry are 18.6 μm and 0.8, respectively. Further, the refinement mechanism of the primary Si grains through the serpentine channel pouring process was analyzed and discussed. In summary, the primary Si nuclei could be easily precipitated due to the chilling effect of the channel inner wall, thus the primary Si grains were greatly refined. Meanwhile, the subsequent alloy melt fluid also promoted the separation of primary Si grains from the inner wall, further refining the primary Si grains.

Analysis of Key Technologies and Equipments Development of Largescale Melted Extrusion Manufacturing Systems

To develop large-scale RP systems used to producing functional parts and large-sized models has become an urgentcall now. In this paper, a large-scale RP system, MEM600-l, based on the melted extrusion manufacturing (MEM)process has been developed successfully. And the key issues to develop such a system are discussed. Based on theactual forming experiment, it is concluded that the MEM600-l works reliably and the forming efficiency is muchhigher than its parallel equipments.

Effects of Cold Working and Annealing on the Microstructure and Critical Current Density of Ag-sheathed BiPbSrCaCuO Superconducting Tapes

Ag-sheathed BiPbSrCaO(2223)superconducting tapes prepared by the powder-in-tube technique were inVeSgated. The Mswt of M layCr and the Jc at 77 K are spengly dspendent on the amouDt of cold wotheg and annchg condition. The Jc bo by uhahal tw aha drawing and rolling. The OPbown annwtg theperawt, boe and coohag de tO madrihe Jc vaiueS were in the range 84()-- 850t, 1bo^2bo h and 50-- loot / h, nyhvejy. The mndum tuSPOrt Jt at 77 K under zero mopetic field was l.33 x l04 A / cm2.

Welding sequences optimization of box structure based on genetic algorithm method

In this article, The genetic algorithm method was proposed, that is, to establish the box structure＇s nonlinear three-dimension optimization numerical model based on thermo-mechanical coupling algorithm, and the objective function of welding distortion has been utilized to determine an optimum welding sequence by optimization simulation. The validity of genetic algorithm method combining with the thermo-mechanical nonlinear finite element model is verified by comparison with the experimental data where available. By choosing the appropriate objective function for the considered case, an optimum weldiing.sequence is determined by a genetic algorithm. All done in this study indicates that the new method presented in this article will have important practical application for designing the welding technical parameters in the future.

3D magnetic field guided sunflower-like nanocatalytic active swarm targeting patients-derived organoids

Nanocatalytic medicine triggering in situ catalytic reactions has been considered as a promising strategy for tumor-selective therapeutics.However,the targeted distribution of nanocatalysts was still low,considering the absence of targeting propulsion capability.Here,encouraged by the fast-developing controllable microrobotics for targeting delivery,a sunflower-like nanocatalytic active swarm(SNCAS)controlled by a three-dimensional(3D)magnetic field was proposed for synergistic tumorselective and magnetic-actively tumor-targeting therapeutics.Furthermore,a patient-derived renal cancer cell 3D organoid was utilized for the verification of the effective tumor therapeutic outcomes.Under the targeted control of 3D magnetic field,the multiple cascade catalytic efficiency of SNCAS based on Fenton reaction was evaluated,resulting in efficient tumor cell apoptosis and death.For the patient-derived organoid treatment,the SNCAS presented significant lethality toward 3D organoid structure to induce cell apoptosis with the collapse of organoid morphology.The targeting efficiency was further enhanced under the magnetic-controllable of SNCAS.Overall,empowered by the magnetic control technology,the synergistic therapeutic strategy based on controllable swarm combined active targeting and tumor-specific catalytic nanomedicine has provided a novel way for advanced cancer therapy.Meanwhile,3D patient-derived organoids were proved as a powerful tool for the effectiveness verification of nanocatalytic medicine.