A wavelength conversion member includes: a substrate; a wavelength converter including phosphor particles excited by excitation light and a binder layer that fixes or adheres the adjacent phosphor particles to one another, the wavelength converter being provided on a front surface side of the substrate; and a light reflecting film that reflects fluorescent light radiated by the phosphor particles, the light reflecting film being provided on at least a part of an interface between the substrate and the wavelength converter, wherein a refractive index of the phosphor particles is larger than a refractive index of the binder layer. It is preferable that the binder layer include nanogaps which are voids with an average diameter of 300 nm or less in an inside.

Systems and methods for imaging in the short wave infrared (SWIR), photodetectors with low dark current and associated circuits for reducing dark currents and methods for generating image information based on data of a photodetector array. A SWIR imaging system may include a pulsed illumination source operative to emit radiation pulses in the SWIR band towards a target resulting in reflected radiation from the target; (b) an imaging receiver including a plurality of Ge PDs operative to detect the reflected SWIR radiation and a controller, operative to control activation of the receiver for an integration time during which the accumulated dark current noise does not exceed the time independent readout noise.

To provide powder for thermal spraying, a method of thermal spraying, and a thermally sprayed coating, which can efficiently work supplying of a dry state powder by using a powder supplying apparatus with a thermal spraying apparatus, and which prevent variation and pulsation or lowering of supplied amount of powder and achieve a required film forming rate, and can obtain a denser coating on the surface of the substrate to be thermally sprayed. [Solution] Powder for thermal spraying 1 is a powder mixture obtained by mixing ceramic powder A whose particle diameter is D.sub.1 and ceramic powder B whose particle diameter is D.sub.2, wherein D.sub.1 is 0.5 to 12μπ.Math. as a median diameter, D.sub.2 is 0.003 to 0.100μ.Math.η as an average particle diameter converted from the BET specific surface area, and when, in the powder mixture, the total weight of the ceramic powder A to be used whose prescribed particle diameter D.sub.1 is W.sub.1, and the total weight of the ceramic powder B to be added to the ceramic powder A is W2, an addition ratio Y of the ceramic powder B defined by Y=W.sub.2/(W.sub.1+W.sub.2) satisfies: Y≥0.2066×D.sub.1.sup.−0.751 and Y≤0.505×D.sub.1.sup.−0.163.

To provide powder for thermal spraying, a method of thermal spraying, and a thermally sprayed coating, which can efficiently work supplying of a dry state powder by using a powder supplying apparatus with a thermal spraying apparatus, and which prevent variation and pulsation or lowering of supplied amount of powder and achieve a required film forming rate, and can obtain a denser coating on the surface of the substrate to be thermally sprayed. [Solution] Powder for thermal spraying 1 is a powder mixture obtained by mixing ceramic powder A whose particle diameter is D.sub.1 and ceramic powder B whose particle diameter is D.sub.2, wherein D.sub.1 is 0.5 to 12μπ.Math. as a median diameter, D.sub.2 is 0.003 to 0.100μ.Math.η as an average particle diameter converted from the BET specific surface area, and when, in the powder mixture, the total weight of the ceramic powder A to be used whose prescribed particle diameter D.sub.1 is W.sub.1, and the total weight of the ceramic powder B to be added to the ceramic powder A is W2, an addition ratio Y of the ceramic powder B defined by Y=W.sub.2/(W.sub.1+W.sub.2) satisfies: Y≥0.2066×D.sub.1.sup.−0.751 and Y≤0.505×D.sub.1.sup.−0.163.

A sintered rare earth oxyfluoride compact is composed of Ln.sub.aO.sub.bF.sub.c (wherein Ln is a rare earth element; and a, b, and c each independently represent a positive number, provided that they are not equal to each other) or Ca-stabilized LnOF as a primary phase and LnOF unstabilized with Ca as a secondary phase. The intensity ratio of the XRD peak of the (018) or (110) plane of the unstabilized LnOF to the highest XRD peak of Ln.sub.aO.sub.bF.sub.c is preferably 0.5% to 30%.

A sintered rare earth oxyfluoride compact is composed of Ln.sub.aO.sub.bF.sub.c (wherein Ln is a rare earth element; and a, b, and c each independently represent a positive number, provided that they are not equal to each other) or Ca-stabilized LnOF as a primary phase and LnOF unstabilized with Ca as a secondary phase. The intensity ratio of the XRD peak of the (018) or (110) plane of the unstabilized LnOF to the highest XRD peak of Ln.sub.aO.sub.bF.sub.c is preferably 0.5% to 30%.

An active material for a fluoride ion secondary battery includes a composite fluoride which contains: an alkali metal or NH.sub.4; a transition metal; and fluorine.

A method of removing fluoride ion from waste liquid is provided, which includes providing a calcium source and a plurality of ceramic particles to a waste liquid containing fluoride ion for forming a plurality of calcium fluoride layers wrapping the ceramic particles. The calcium fluoride layers are connected to form a calcium fluoride bulk. The ceramic particles are embedded in the calcium fluoride bulk. The ceramic particles and the calcium fluoride bulk have a weight ratio of 1:4 to 1:20.

A method of removing fluoride ion from waste liquid is provided, which includes providing a calcium source and a plurality of ceramic particles to a waste liquid containing fluoride ion for forming a plurality of calcium fluoride layers wrapping the ceramic particles. The calcium fluoride layers are connected to form a calcium fluoride bulk. The ceramic particles are embedded in the calcium fluoride bulk. The ceramic particles and the calcium fluoride bulk have a weight ratio of 1:4 to 1:20.

Described herein are cold-sintered ceramic polymer composites and processes for making them from ceramic precursor materials and monomers and/or oligomers. The cold sintering process and wide variety of monomers permit the incorporation of diverse polymeric materials into the ceramic.