摘要:
An apparatus and method for continuously monitoring the liquid nitrogen level a liquid nitrogen container and automatically refilling liquid nitrogen from a liquid nitrogen reservoir when the liquid nitrogen in the container falls below a predetermined level. The apparatus comprises a liquid nitrogen level sensing element, which contains a superconducting material, such as a YbaCuO type superconductiing material, disposed on a non-conducting substrate, such as magnesium oxide. The superconducting material is selected such that it has a critical temperature approximately equal to the boiling point temperature of liquid nitrogen. The superconducting material is placed near the predetermined level and, under normal conditions, the superconducting material exhibits zero or near zero resistance. When the level of liquid nitrogen falls below the predetermined level due to heat loss or other reasons, the resistance of the superconducting material will increase substantially, thus triggering a control means to open a solenoid valve and allow liquid nitrogen to flow from the reservoir to the container. The liquid nitrogen level sensing element can be prepared by photochemically etching a superconducting layer, which has been deposited on the non-conducting substrate, in accordance with a serpentine design, to thereby increase the sensitivity and reliability thereof.
摘要:
A process for preparing powder of high temperature oxide superconductors of Bi-Pb-Sr-Ca-Cu-O type. In an aqueous solution of nitrate salts of Bi, Pb, Sr, Ca, and Cu metals, an appropriate ratio of triethylamine/oxalic acid was added to form a coprecipitate. Through the process of calcination at a temperature in the range of 750.degree. C. to 800.degree. C. and sintering at a temperature of 860.degree. C., a uniform and fine powder superconductive metal oxide having a critical temperature of 110K is obtained as the final product.
摘要:
A citrate/ethylenediamine gel method for forming oxide superconductors of the Y-Ba-Cu-O, Bi-Ca-Sr-Cu-O, Tl-Ca-Ba-Cu-O system by employing the nitrates of the individual metals and citric acid. Ethylenediamine is then added to form gels. These materials then undergo calcination and sintering processes. The respective superconductors obtained possess a superconducting zero resistance temperature at 93K, 78K and 118K respectively.
摘要:
This invention provides a process for the preparation of the precursor used in the fabrication of Y--Ba--Cu--O superconductors. This process mainly uses solgel technology via the nitrate route by using a dicarboxylic acid. Among the dicarboxylic acids, oxalic acid is the best for preparing the precursor which can be fabricated into a good superconductor.
摘要:
A phosphor comprising an oxynitride compound having a chemical formula of A2-mE3O2N4:Mm, wherein A comprises an alkaline-earth element, E comprises a IVA group element, M is an activator comprising a bivalent rare-earth element, and 0.00001≦m≦1.0, wherein A is at least one element selected from the group consisting of Mg, Ca, Sr and Ba; E is at least one element selected from the group consisting of C, Si, Ge, and Sn; and M is at least one element selected from the group consisting of Lu, Sc, La, Gd, Tb, Eu, and Sm.
摘要:
The present disclosure provides an illuminating system including a light emitting diode (LED); and a tunable luminescent material disposed approximate the light-emitting diode, wherein the tunable luminescent material includes alkaline earth metal (AE) and silicon aluminum nitride doped by a rare earth element (RE), formulated as (AE)Si6−pAlpN8, wherein p is a parameter defining a relative aluminum content in weight and p is greater than zero.
摘要:
The present invention fluorescence material has a particle diameter of the crystal area defined as dc, and the scope of dc is: 150 nm≧dc≧10 nm. The coat of the outside of the fluorescence material has one sheet of coating medium at least. Of course, there is at least a geometrical etching layer on the particle of the fluorescence material. The above-described structures will promote the extraction efficiency of light.
摘要:
The present disclosure provides a radiation device. The radiation device includes a first light emitting diode (LED) operable to emit light having a first central wavelength; a second LED configured adjacent the first LED and operable to emit light having a second central wavelength substantially less than the first central wavelength; and a luminescent material disposed on the first LED and the second LED. The luminescent material includes a strontium silicon nitride (SrSi6N8) doped by one of cerium (Ce3+) and cerium, lithium (Ce3+, Li+).
摘要:
The present invention provides a phosphor composition for AC LEDs, which is represented by the following formula (I): M1−x−ySi2O2−wN2+2w/3:Eux,Ry (I) wherein, M, R, x, y, and w are defined the same as the specification. In addition, the present invention also provides an AC LED manufactured with the same.
摘要:
A phosphor material for producing white light under excitation of UV light and a method for making the same. The phosphor material is an alkaline-earth silicates compound with a chemical formula of (A2-x-yCexEuy)SiO4. A is one or more elements selected from the collection of Ba, Sr and Ca alkaline-earth metals. The range of x and y correspond to 0