Abstract: A composition, such as a catalyst precursor or a catalyst comprising a Cr coated silica support with particularly defined levels of Na and Al, such that the resulting Cr/Silica catalyst has an increased MI potential is disclosed. In an embodiment, the disclosed catalyst composition comprises a silica-containing substrate made using a base-set gel and comprising a catalytically active metal consisting of Cr, with Al impurities of less than 50 ppm and Na in an amount of less than 800 ppm of the catalyst composition. The disclosed composition has an increased MI potential over a catalyst having higher Al content, a lower Na:Al ratio, or both. Methods of making the disclosed composition, and methods of using it to prepare a polyethylene are also disclosed.

Abstract: A composition, such as a catalyst precursor or a catalyst comprising a Cr coated silica support with particularly defined levels of Na and Al, such that the resulting Cr/Silica catalyst has an increased MI potential is disclosed. In an embodiment, the disclosed catalyst composition comprises a silica-containing substrate made using a base-set gel and comprising a catalytically active metal consisting of Cr, with Al impurities of less than 50 ppm and Na in an amount of less than 800 ppm of the catalyst composition. The disclosed composition has an increased MI potential over a catalyst having higher Al content, a lower Na:Al ratio, or both. Methods of making the disclosed composition, and methods of using it to prepare a polyethylene are also disclosed.

Abstract: A composition, such as a catalyst precursor or a catalyst comprising a Cr coated silica support with particularly defined levels of Na and Al, such that the resulting Cr/Silica catalyst has an increased MI potential is disclosed. In an embodiment, the disclosed catalyst composition comprises a silica-containing substrate made using a base-set gel and comprising a catalytically active metal consisting of Cr, with Al impurities of less than 50 ppm and Na in an amount of less than 800 ppm of the catalyst composition. The disclosed composition has an increased MI potential over a catalyst having higher Al content, a lower Na:Al ratio, or both. Methods of making the disclosed composition, and methods of using it to prepare a polyethylene are also disclosed.

Abstract: A process for preparation of silica xerogel catalyst support particles having high surface areas involves ageing a silica hydrogel at a pH from 3 to 5 and at a temperature of 45° C. or more. The ageing at low pH leads to a silica gel which may be converted to a xerogel having a pore volume of 1.5 cm3/g or more and a surface area of 600 m2/g or more by removal of liquid from the pore structure by solvent exchange with a liquid solvent having a surface tension of 35 mN/m or less. The resulting particles are useful for carrying catalyst metal compounds, such as a chromium compounds, in the pore structure to act as catalyst precursors. These catalyst precursors may be activated into porous catalyst particles suitable for use for olefin polymerization to provide high activity and for forming high molecular weight polymers (low MI polymers) with good crack resistance.

Abstract: A process for preparation of silica xerogel catalyst support particles having high surface areas involves ageing a silica hydrogel at a pH from 3 to 5 and at a temperature of 45° C. or more. The ageing at low pH leads to a silica gel which may be converted to a xerogel having a pore volume of 1.5 cm3/g or more and a surface area of 600 m2/g or more by removal of liquid from the pore structure by solvent exchange with a liquid solvent having a surface tension of 35 mN/m or less. The resulting particles are useful for carrying catalyst metal compounds, such as a chromium compounds, in the pore structure to act as catalyst precursors. These catalyst precursors may be activated into porous catalyst particles suitable for use for olefin polymerization to provide high activity and for forming high molecular weight polymers (low MI polymers) with good crack resistance.

Abstract: A process for preparation of silica xerogel catalyst support particles having high surface areas involves ageing a silica hydrogel at a pH from 3 to 5 and at a temperature of 45° C. or more. The ageing at low pH leads to a silica gel which may be converted to a xerogel having a pore volume of 1.5 cm3/g or more and a surface area of 600 m2/g or more by removal of liquid from the pore structure by solvent exchange with a liquid solvent having a surface tension of 35 mN/m or less. The resulting particles are useful for carrying catalyst metal compounds, such as a chromium compounds, in the pore structure to act as catalyst precursors. These catalyst precursors may be activated into porous catalyst particles suitable for use for olefin polymerisation to provide high activity and for forming high molecular weight polymers (low MI polymers) with good crack resistance.

Abstract: Disclosed is a surface-emitting type light-emitting diode including a substrate, a p-n junction layer elevated on a portion of the substrate to emit light, and a first isolator layer formed on a sidewall of the p-n junction layer as well as a periphery portion of a top surface of the p-n junction layer except for a central region of the top surface.

Abstract: A time division duplexing (TDD) transmission/reception apparatus and method are provided. The TDD transmission/reception apparatus includes: a transmitter which generates a transmitted signal; an antenna which transmits the transmitted signal to an external device and receives a received signal from an external device; a receiver which restores source data by demodulating the received signal; and a polarized duplexer which has a first end connected to the transmitter and the receiver and a second end connected to the antenna and comprises an inclined surface, the inclined surface polarizing the transmitted signal and the received signal such that the directivity of the transmitted signal and the directivity of the received signal are perpendicular to each other.

Abstract: A dielectric ceramic filter with a metal guide can is provided. The dielectric ceramic filter includes a metal guide can coupled to and projecting from both input/output ends of the dielectric ceramic filter. Alternatively, the dielectric ceramic filter includes: a dielectric block having a plurality of vertical grooves formed in its side surfaces, wherein a conductive material is coated on all surfaces of the dielectric block except its ends; and a metal guide can covering both ends of the dielectric block, wherein the metal guide can is a conductive metal plate projecting from both ends of the dielectric block.

Abstract: Provided is a near-field microscope using a dielectric resonator, which makes it possible to minimize influences by external environments, and to enhance its sensitivity, resolution and function by adjusting the distance between a sample and an apex of a probe. The near-field microscope includes a wave source, a dielectric resonator, a probe, a distance adjusting unit, and a detector. The wave source generates a wave, and a frequency of the wave is adjustable by the wave source. The dielectric resonator propagates the wave from the wave source, and a resonance frequency, impedance, a Q factor and an electromagnetic wave mode of the wave is freely adjustable. The probe scans the wave output from the dielectric resonator on a sample. The distance adjusting unit measures a distance between the probe and the sample and maintains the distance to a predetermined value.