The absorbance or emission wavelength of composite materials comprising a transition metal doped shell disposed over a rare earth doped core and a functionalizable group on the surface of the transition metal doped shell can change upon subjection to a carboxylic acid. This method of changing the absorbance or emission wavelength of a composite material can be used to identify counterfeit currency using an ink comprising a composite material.

Concealed mark preparation with core-shell luminosphores for customs security check system and application thereof, to address that infrared luminescent materials have not been used in senseless customs clearance field, absorption cross sections of infrared luminescent materials currently available are not big enough, and upconversion luminescence intensity thereof is low, consequently, the luminescent marks are not clear enough to recognize marked abnormal luggage, and provide a following solution: step 1: preparing TiQ.sub.2; step 2: preparing Ag@TiO.sub.2 composite nanoparticles; step 3: preparing Ag@TiQ.sub.2@NaYF.sub.4:Yb.sup.3+, Er.sup.3+ luminescent nanoparticles; step 4: making concealed luggage marks. Ag@TiQ.sub.2@NaYF.sub.4:Yb.sup.3+, Er.sup.3+ luminescent nanoparticles according to the present invention has superior luminescent intensity than pure NaYF.sub.4:Yb.sup.3+, Er.sup.3+, and luminescent materials prepared in this method can be disseminated in organic solution such as ethanol and methanol for use in preparing concealed marks to mark susceptible luggage and provides a research direction for senseless, intelligent and safe customs clearance.

The invention provides novel biocompatible upconversion nanoparticle (UCNP) that comprises a core of cubic nanocrystals (e.g., comprising α-Na Ln.sub.a, Ln.sub.b Ln.sub.c F.sub.4) and an epitaxial shell (e.g., formed from CaF.sub.2; wherein Ln.sub.b is Yb), and related methods of preparation and uses thereof.

A method of fracturing multiple productive zones of a subterranean formation penetrated by a wellbore is disclosed. The method comprises injecting a fracturing fluid into each of the multiple production zones at a pressure sufficient to enlarge or create fractures in the multiple productive zones, wherein the fracturing fluid comprises an upconverting nanoparticle that has a host material, a dopant, and a surface modification such that the upconverting nanoparticle is soluble or dispersible in water, a hydrocarbon oil, or a combination thereof; recovering a fluid from one or more of the multiple production zones; detecting the upconverting nanoparticle in the recovered fluid by exposing the recovered fluid to an excitation radiation having a monochromatic wavelength; and identifying the zone that produces the recovered fluid or monitoring an amount of water or oil in the produced fluid by measuring an optical property of the upconverting nanoparticle in the recovered fluid.

The present application provides an apparatus for a photo-alignment process. The apparatus for a photo-alignment process includes a reflector, an up-conversion layer, and a polarizer optically coupled together. The reflector is configured to reflect an infrared light and provide a reflected infrared light to the up-conversion layer. The up-conversion layer is configured to convert the reflected infrared light to an ultraviolet light, and provide the ultraviolet light to the polarizer. The polarizer is configured to convert the ultraviolet light to a polarized ultraviolet light for the photo-alignment process.

A scintillation crystal can include Ln.sub.(1-y)RE.sub.yX.sub.3, wherein Ln represents a rare earth element, RE represents a different rare earth element, y has a value in a range of 0 to 1, and X represents a halogen. In an embodiment, the scintillation crystal is doped with a Group 1 element, a Group 2 element, or a mixture thereof, and the scintillation crystal is formed from a melt having a concentration of such elements or mixture thereof of at least approximately 0.02 wt. %. In another embodiment, the scintillation crystal can have unexpectedly improved proportionality and unexpectedly improved energy resolution properties. In a further embodiment, a radiation detection apparatus can include the scintillation crystal, a photosensor, and an electronics device. Such a radiation detection apparatus can be useful in a variety of applications.

The present invention relates, in general terms, to X-ray detecting films and uses thereof. The present invention also relates to methods of fabricating the X-ray detecting films. In particular, the X-ray detecting film comprises persistent luminescent nanoparticles dispersed within a flexible polymer matrix, wherein the persistent luminescent nanoparticles are dispersed in the flexible polymer matrix at a concentration of about 0.1% to about 100%.

Disclosed herein is a material, comprising a first metal halide that is operative to function as a scintillator; where the first metal halide excludes cesium iodide, strontium iodide, and cesium bromide; and a surface layer comprising a second metal halide that is disposed on a surface of the first metal halide; where the second metal halide has a lower water solubility than the first metal halide.

A method of fracturing multiple productive zones of a subterranean formation penetrated by a wellbore is disclosed. The method comprises injecting a fracturing fluid into each of the multiple production zones at a pressure sufficient to enlarge or create fractures in the multiple productive zones, wherein the fracturing fluid comprises an upconverting nanoparticle that has a host material, a dopant, and a surface modification such that the upconverting nanoparticle is soluble or dispersible in water, a hydrocarbon oil, or a combination thereof; recovering a fluid from one or more of the multiple production zones; detecting the upconverting nanoparticle in the recovered fluid by exposing the recovered fluid to an excitation radiation having a monochromatic wavelength; and identifying the zone that produces the recovered fluid or monitoring an amount of water or oil in the produced fluid by measuring an optical property of the upconverting nanoparticle in the recovered fluid.

Methods are presented for tuning the time-domain emissive profile of single upconversion nanoparticles using a number of different techniques so as to increase the coding capacity at the nanoscale. The disclosure also relates to time-resolved wide-field imaging and deep-learning techniques to decode the nanoparticle fingerprints.