Abstract: Disclosed herein is a fan and shroud assembly comprising: a fan having a hub rotating on a shaft and a plurality of blades extending outward from the hub; and a shroud surrounding the fan for controlling air blast by rotation of the fan, wherein the shroud comprises: a guide ring part spaced apart at a predetermined interval from the periphery of the fan which connects ends of the blades; and swirl preventing means formed on the guide ring part for preventing swirling airflow along the periphery of the fan connecting the ends of the blades. The fan and shroud assembly can minimize generation of swirling airflow and backflow and provide improved noise-reduction effect.

Abstract: The present invention relates to an axial flow fan which prevents the deformation of blades even when rotated at high speed, thus promoting the structural stability. The axial flow fan includes a hub and a plurality of blades, which are arranged along a circumferential outer surface of the hub in a radial direction such that the direction of a sweeping angle of each of the blades alternately changes between a blade root and a blade tip. A chord length, which is the length from a leading edge to a trailing edge of the blade, gradually reduces from the blade root to an intermediate portion of the blade, while the chord length gradually increases from a predetermined position on the intermediate portion of the blade to the blade tip.

Abstract: A fan and shroud assembly includes a fan having a hub rotating around one shaft and a plurality of blades extending outwardly from the hub, a shroud encompassing the fan to adjust airflow by rotation of the fan, a guide ring portion located at a position where a predetermined gap exists between the shroud and a circumference connecting end tips of the blades so that the fan is supported by the shroud and rotates, and a plurality of swirl prevention units integrally formed with the guide ring portion to prevent a vortex from proceeding along the circumference in the predetermined gap, each swirl prevention unit having a shape in which the length of a circular arc passing through each of the swirl prevention units with respect to the center of the shroud decreases as the arc is closer to the center of the shroud.

Abstract: A low-noise amplifier for a mobile communication terminal maintains linearity with the least current consumption. A low-noise amplifier controller detects a signal-to-noise ratio (SNR) of a received signal, and outputs a control signal of a preset voltage when the SNR is lower than a predetermined SNR even though AGC AMP controller increases the AGC gain according to field strength. A bias circuit increases a bias current according to the control signal output from the low-noise amplifier controller. A low-noise amplifier amplifies the received signal to a preset level according to the bias current provided from the bias circuit.

Abstract: A fan and shroud assembly includes a fan has a hub rotating around one shaft and a plurality of blades extending outwardly from the hub, a shroud encompassing the fan to adjust airflow by rotation of the fan, a guide ring portion located at a position where a predetermined gap exists between the shroud and a circumference connecting end tips of the blades so that the fan coupled to the shroud rotates, and a plurality of swirl prevention units integrally formed with the guide ring portion to prevent a motion of vortex proceeding along a circumference connecting end tips of the blades between the guide ring portion and the circumference, each swirl prevention unit having a shape in which the length of a circular arc passing each of the swirl prevention units with respect to the center of the shroud decreases as the arc is closer to the center of the shroud.

Abstract: A keyfact-based text retrieval method and a keyfact-based text index method that describes the formalized concept of a document by a pair comprising an object that is the head and a property that is the modifier and uses the information described by the pairs as index information for efficient document retrieval. A keyfact-based text retrieval system includes keyfact extracting, keyfact indexing, and keyfact retrieving. The keyfact extracting analyzes a document collection and a query and extracts keywords and keyfacts. The keywords do not have part-of-speech ambiguity and the keyfacts are extracted from the keywords. The keyfact indexing calculates the frequency of the keyfacts and generates a keyfact list of the document collection for a keyfact index structure. The keyfact retrieving receive a keyfact of the query and keyfacts of the document collection and defines a keyfact-based retrieval model in consideration of a weight factor of the keyfact pattern and generates a retrieval result.

Abstract: A low-noise amplifier for a mobile communication terminal maintains linearity with the least current consumption. A low-noise amplifier controller detects a signal-to-noise ratio (SNR) of a received signal, and outputs a control signal of a preset voltage when the SNR is lower than a predetermined SNR even though AGC AMP controller increases the AGC gain according to field strength. A bias circuit increases a bias current according to the control signal output from the low-noise amplifier controller. A low-noise amplifier amplifies the received signal to a preset level according to the bias current provided from the bias circuit.