The invention relates to a method for growing a bulk single crystal, wherein the method comprises the steps of inserting a starting material into a crucible, melting the starting material in the crucible by heating the starting material, arranging a thermal insulation lid at a distance above a melt surface of said melt such that at least a central part of the melt surface is covered by the lid, and growing the bulk single crystal from the melt by controllably cooling the melt with the thermal insulation lid arranged above the melt surface.

The invention relates to a method for growing a bulk single crystal, wherein the method comprises the steps of inserting a starting material into a crucible, melting the starting material in the crucible by heating the starting material, arranging a thermal insulation lid at a distance above a melt surface of said melt such that at least a central part of the melt surface is covered by the lid, and growing the bulk single crystal from the melt by controllably cooling the melt with the thermal insulation lid arranged above the melt surface.

The present invention provides a low-dimensional perovskite-structured metal halide and a preparation method and application thereof. The general formulas of the compositions of the low-dimensional perovskite-structured metal halide are AB.sub.2X.sub.3, A.sub.2BX.sub.3, and A.sub.3B.sub.2X.sub.5; wherein, A is at least one of Li, Na, K, Rb, Cs, In, and Tl; B is at least one of Cu, Ag, and Au; and X is at least one of F, Cl, Br, and I.

The present invention provides a low-dimensional perovskite-structured metal halide and a preparation method and application thereof. The general formulas of the compositions of the low-dimensional perovskite-structured metal halide are AB.sub.2X.sub.3, A.sub.2BX.sub.3, and A.sub.3B.sub.2X.sub.5; wherein, A is at least one of Li, Na, K, Rb, Cs, In, and Tl; B is at least one of Cu, Ag, and Au; and X is at least one of F, Cl, Br, and I.

Disclosed are a Li.sup.+ doped metal halide scintillation crystal with a zero-dimensional perovskite structure, a preparation method and use thereof. The scintillation crystal has a chemical formula of Cs.sub.3-xCu.sub.2I.sub.5:xLi, where x is in a range of 0.003 to 0.3. The method for preparing the scintillation crystal comprises the steps of: weighting and fully mixing a CuI powder, a CsI powder and a LiI powder in a molar ratio of 2:(3-x):x in an inert atmosphere to obtain a mixed powder, and growing into the scintillation crystal from the mixed powder by Bridgman Stockbarger method. After excited, the scintillation crystal could emit a broadband blue light in a range of 350-550 nm, with an intensity much higher than that of the original pure component crystal. The existence of Li.sup.+ further expands the application of the scintillation crystals from X/γ-ray detection to neutron detection.

Disclosed are a Li.sup.+ doped metal halide scintillation crystal with a zero-dimensional perovskite structure, a preparation method and use thereof. The scintillation crystal has a chemical formula of Cs.sub.3-xCu.sub.2I.sub.5:xLi, where x is in a range of 0.003 to 0.3. The method for preparing the scintillation crystal comprises the steps of: weighting and fully mixing a CuI powder, a CsI powder and a LiI powder in a molar ratio of 2:(3-x):x in an inert atmosphere to obtain a mixed powder, and growing into the scintillation crystal from the mixed powder by Bridgman Stockbarger method. After excited, the scintillation crystal could emit a broadband blue light in a range of 350-550 nm, with an intensity much higher than that of the original pure component crystal. The existence of Li.sup.+ further expands the application of the scintillation crystals from X/γ-ray detection to neutron detection.

The present disclosure discloses, in one arrangement, a scintillator material made of a metal halide with one or more additional group-13 elements. An example of such a compound is Ce:LaBr.sub.3 with thallium (Tl) added, either as a codopant or in a stoichiometric admixture and/or solid solution between LaBr.sub.3 and TlBr. In another arrangement, the above single crystalline iodide scintillator material can be made by first synthesizing a compound of the above composition and then forming a single crystal from the synthesized compound by, for example, the Vertical Gradient Freeze method. Applications of the scintillator materials include radiation detectors and their use in medical and security imaging.

The present disclosure discloses, in one arrangement, a scintillator material made of a metal halide with one or more additional group-13 elements. An example of such a compound is Ce:LaBr.sub.3 with thallium (Tl) added, either as a codopant or in a stoichiometric admixture and/or solid solution between LaBr.sub.3 and TlBr. In another arrangement, the above single crystalline iodide scintillator material can be made by first synthesizing a compound of the above composition and then forming a single crystal from the synthesized compound by, for example, the Vertical Gradient Freeze method. Applications of the scintillator materials include radiation detectors and their use in medical and security imaging.

The present invention relates to a substrate-triggered single crystal superalloy directional solidification process, including: (1) preparing a single crystal substrate material having crystallographic characteristics that match crystallographic characteristics of the single crystal superalloy; (2) fabricating a single crystal substrate chilling plate using the obtained single crystal substrate material; and (3) applying the obtained single crystal substrate chilling plate in a directional solidification apparatus, and then preparing a single crystal alloy product by performing superalloy melting and directional solidification. Compared with grain selector method and seeding with grain selector method, in addition to control the crystallographic orientation of the single crystal superalloy precisely, the present invention could reduce the height of block and the whole mold through canceling the spiral grain selector, significantly improve the axial heat dissipation and temperature gradient at the solid-liquid interface, and then reduce the occurrence of freckles and stray grains near platform.

The present invention relates to a substrate-triggered single crystal superalloy directional solidification process, including: (1) preparing a single crystal substrate material having crystallographic characteristics that match crystallographic characteristics of the single crystal superalloy; (2) fabricating a single crystal substrate chilling plate using the obtained single crystal substrate material; and (3) applying the obtained single crystal substrate chilling plate in a directional solidification apparatus, and then preparing a single crystal alloy product by performing superalloy melting and directional solidification. Compared with grain selector method and seeding with grain selector method, in addition to control the crystallographic orientation of the single crystal superalloy precisely, the present invention could reduce the height of block and the whole mold through canceling the spiral grain selector, significantly improve the axial heat dissipation and temperature gradient at the solid-liquid interface, and then reduce the occurrence of freckles and stray grains near platform.