Abstract: Disclosed herein are several organic compounds having electron-transporting and/or hole-blocking performance and their preparation method and use and the OLEDs comprising the organic compound. The organic compounds exhibit high ionization potential (IP), electron affinity (Ea), glass transition temperature (Tg) and high electron mobility, and are a kind of good electron-transporting material with good hole-blocking ability. The devices comprising these compounds as one of the emitting layer, electron-transporting layer (ETL) and hole-blocking layer (HBL) show improved efficiency and better color purity.

Abstract: Refrigerant mixtures used in the lower temperature stage of two-stage cascade refrigeration systems and obtained by physical mixing of ethane, hexafluoroethane, or/and trifluoromethane. One of the refrigerant mixtures comprises ethane and hexafluoroethane. Another refrigerant mixture comprises ethane and trifluoromethane. Yet another one of the refrigerant mixtures comprises ethane, hexafluoroethane, and trifluoromethane.

Abstract: The present invention provides a cesium-rubidium-borate nonlinear optical crystal, which is represented by the chemical formula CsxRb1-xB3O5 (0<x<1), and belongs to the P212121 space group with the unit cell parameters in the following range: a=8.202-8.514 ?, b=10.075-9.140 ?, c=5.375-6.207 ? and Z=4. A preparation method of the crystal is as follows: a cesium salt, a rubidium salt and a boron-containing compound are mixed pro rata, heated, kept at a temperature, and then cooled down to obtain the cesium-rubidium-borate. The cesium-rubidium-borate and a flux are mixed and heated to form a melt to obtain a mixing melt. Then a seed crystal attached to a seed rod is dipped into the mixing melt and the seed rod is rotated simultaneously. The melt is kept at 620-780° C., and then cooled down slowly at a rate of 0-5° C. per day. The obtained crystal is drawn out of the melt surface and cooled down to room temperature. Thereby, the cesium-rubidium-borate nonlinear optical crystal is obtained.