Papers by Author: Jing He Liu

Abstract: The 5at.% Yb3+-doped YAG crystal was grown by the Czochraski method, and the crystal growth process was investigated. the optimal process parameters were determined as follows: The crystal growing rate for Shoulder growth and equal-diameter growth were 0.8mm/h and 1mm/h, respectively. The optimal Rotation speed of this crystal was 15rad/min, and the axial temperature gradient was 0.01−0.05°C/mm. The impact factors to crystal growth were analyzed theoretically, such as growth rate, rotation speed, thermal effect and crystal size.

Abstract: The Tm,Ho:BaY₂F₈ single crystal was successfully grown by the Cz method. The optimal technical parameters obtained are as follows: the pulling rate is 0.5—0.6mm/h; the rotation speed is 5—7rpm; the cooling rate is 10°C/h. The result of XRD curve shows that as-grown Tm,Ho:BaY₂F₈ laser crystal belongs to the monoclynicsystem and space group I41/a, the cell parameters calculated are: a = 0.69829 nm, b = 1.0519 nm, c = 0.42644 nm, β=99.676°, Z=2. Absorption spectra of Tm,Ho:BaY₂F₈ laser crystal at room temperature were measured and analysed, the absorption cross-section at 781nm calculated are 7.66×10^-21cm^-2.

Abstract: Hydroxyapatite (HA) has attracted many attentions because it has a similar structure to that of human bones and favorable biocompatibility. However, the antibacterial effect of HA must be improved. In this paper, HA nanoparticles were prepared by a simple method. Then, Ag-carrying HA powder (Ag-HA) was prepared by an ion-solution reaction and its antibacterial property was investigated. The results showed that Ag-HA powder had excellent ability in inhibiting the growth of two species of bacteria, namely E. coli and S. aureus. Ag ion was believed to play a key role in killing bacteria.

Abstract: Three fillers i.e. micro glass bead, nano-montmorillonite and graphite at 8wt% were respectively filled into ultrahigh molecular weight polyethylene (UHMWPE). The microstructure, mechanical properties were investigated. The results indicated that: The performances of three kinds of composites, such as morphology, tensile strength, impact strength, elongation at break and fraction wear, were in great difference. The bonding of interface between glass bead and UHMWPE was not firm, but nano-montmorillonite and graphite as filler dispersed in matrix evenly and coupling tight. Due to filling the filler, the tensile strength, impact strength and elongation at break decreased in varying degree compared with that of simple UHMWPE, but impact strengths reduced only a few; however the wear resistance of composite filled by graphite was improved obviously.