We provide methods and apparatus for preparing crystalline-clad and crystalline core optical fibers with minimal or no breakage by minimizing the influence of thermal stress during a liquid phase epitaxy (LPE) process as well as the fiber with precisely controlled number of modes propagated in the crystalline cladding and crystalline core fiber via precisely controlling the diameter of crystalline fiber core with under-saturated LPE flux. The resulting crystalline cladding and crystalline core optical fibers are also reported.

Provided are compounds of the formula M.sup.A.sub.1-xM.sup.B.sub.xX.sup.A.sub.1-yX.sup.B.sub.yQ.sup.A.sub.1-zQ.sup.B.sub.z, wherein M.sup.A and M.sup.B are selected from Si, Ge, Sn, and Pb, X.sup.A and X.sup.B are selected from F, Cl, Br and I, Q.sup.A and Q.sup.B are selected from P, As, Sb and Bi, and x, y and z are 0 to 0.5, as well as doped variants thereof, useful as semiconducting materials. Due a double helix structure formed by the constituting atoms, the compounds are particularly suitable to provide nano-materials, in particular nanowires, for diverse applications.

According to an aspect, a method of preparing quantum dots includes a first operation of preparing a quantum dot seed solution; a second operation of growing a quantum dot by continuously injecting a quantum dot cluster solution into the quantum dot seed solution; a third operation of separating the grown quantum dot and dispersing the quantum dot in a solvent; and a fourth operation of further growing the quantum dot by continuously injecting the quantum dot cluster solution into the dispersed quantum dot.

According to an aspect, a method of preparing quantum dots includes a first operation of preparing a quantum dot seed solution; a second operation of growing a quantum dot by continuously injecting a quantum dot cluster solution into the quantum dot seed solution; a third operation of separating the grown quantum dot and dispersing the quantum dot in a solvent; and a fourth operation of further growing the quantum dot by continuously injecting the quantum dot cluster solution into the dispersed quantum dot.

The present invention is a process for bio synthesis of nano arsenic trioxide defined by its low toxicity, higher bio availability and nano particle size with the aid of buttermilk, goat urine, dolichos biflorous and other plant materials such as ginger, momordica charantia and musa paradisiaca. The invention is carried out in different steps involving purification of crude form of arsenic trioxide by boiling it with buttermilk, goat urine and extract of dolichos biflorous in subsequent steps, followed by the trituration of the bio purified arsenic trioxide with extracts of ginger and momordica charantia in subsequent steps and heating of the dry product obtained after trituration with musa paradisiaca resulting in the production of novel nano arsenic trioxide. The product is effective in the treatment of various diseases including different types of cancer in animals and humans. The product obtained through the process is less toxic with higher bio availability.

An optical thin film includes a support layer and a dielectric layer on the support layer. The dielectric layer has a refractive index greater than that of the support layer. The dielectric layer includes a compound ADX, which includes a Group 3 element A, a Group 5 element D, and an element X having an atomic weight smaller than an atomic weight of A or D. The optical thin film may exhibit light transmission having a high refractive index and low absorptivity.

An optical thin film includes a support layer and a dielectric layer on the support layer. The dielectric layer has a refractive index greater than that of the support layer. The dielectric layer includes a compound ADX, which includes a Group 3 element A, a Group 5 element D, and an element X having an atomic weight smaller than an atomic weight of A or D. The optical thin film may exhibit light transmission having a high refractive index and low absorptivity.

A process for purification of hydrofluoric acid reduces the content of heavy metals, including arsenic, to values lower than five parts per million, without using any chemicals and with an integrated design of hot and cold streams that provide low energy consumption. The process allows extraction of heavy metals, especially arsenic, with minimal waste generation and while maintaining an original oxidation state, which for the case of arsenic is +3, so that the residue can he converted into a product with commercial value, such as arsenious acid. The process includes operation of four systems, namely, a hydrofluoric acid purification system, an arsenic concentration system, a hot water system, and a cold water system. The extraction of heavy metals is performed by synchronized operations of these four systems.

We provide methods and apparatus for preparing crystalline-clad and crystalline core optical fibers with minimal or no breakage by minimizing the influence of thermal stress during a liquid phase epitaxy (LPE) process as well as the fiber with precisely controlled number of modes propagated in the crystalline cladding and crystalline core fiber via precisely controlling the diameter of crystalline fiber core with under-saturated LPE flux. The resulting crystalline cladding and crystalline core optical fibers are also reported.

According to an aspect, a method of preparing quantum dots includes a first operation of preparing a quantum dot seed solution; a second operation of growing a quantum dot by continuously injecting a quantum dot cluster solution into the quantum dot seed solution; a third operation of separating the grown quantum dot and dispersing the quantum dot in a solvent; and a fourth operation of further growing the quantum dot by continuously injecting the quantum dot cluster solution into the dispersed quantum dot.