Abstract: A fuel cell system including a quartz crystal microbalance (QCM) concentration sensor, and in particular, comprising a bypass channel structure useful for installing a QCM concentration sensor to a fuel cell system. The fuel cell system includes a fuel cell stack generating electric energy by an electrochemical reaction of a hydrogen-containing fuel and an oxidant, a fuel cell including a fuel supplying unit supplying the hydrogen-containing fuel to the fuel cell stack, a QCM concentration sensing unit for measuring the concentration of a fluid in the fuel cell, and a drive controlling unit for controlling the operation of the fuel cell according to an output of the QCM concentration sensing unit.

Abstract: A fuel cell system including a correction means capable of accurately correcting a concentration sensing value according to temperature is discussed. The fuel cell system may include an electricity generating unit generating electric energy by means of the electrochemical reaction of fuel and an oxidizer, a fuel supplying unit supplying the fuel to the electricity generating unit, a main concentration sensor for measuring the concentration of the fuel, a reference cell filled with reference solution and including a reference concentration sensor for measuring the concentration of the reference solution, and/or a drive controlling unit controlling the operation of the electricity generating unit based on the concentration values measured in the main concentration sensor and the reference concentration sensor.

Abstract: An apparatus and method adjust an adaptive service bandwidth in a mobile communication system in which differentiated services for guaranteeing QoS are provided. Services are provided by using a bandwidth greater than an accepted reference value when resources of the network have a margin, and by using a weighted value according to a class when the network is in an overload state to efficiently transmit a packet and provide a user with optimal services.

Abstract: Provided is a detector, a gas scrubber comprising the detector for identifying a residual lifetime of an absorbent material contained in a gas scrubber for purifying a harmful exhaust gas, and a method of identifying the residual lifetime of the absorbent material. The detector comprises a solid chemical material, the color of which changes when it comes in contact with the untreated exhaust gas due to loss of absorbing power of the absorbent material, a detection window containing the solid chemical material therein, therethrough the visual identification of the color change of the solid chemical material can be made, and connecting units placed on an upper and lower end of the detection window. The visual identification of the color change of the solid chemical material through the detection window enables the continuous and safe identification of the residual lifetime of the absorbent material and the replacement time, thereby increasing the reliability of the gas scrubber.

Abstract: Disclosed is a method for reselling content. The method comprises receiving sale information for particular content to be resold from a seller terminal in reply to a request by a seller who wishes to resell the content over a communication network, and registering the corresponding content as secondhand content; providing the corresponding secondhand content to a buyer terminal in reply to a request by a buyer who wishes to buy the secondhand content, and transmitting sale information for the secondhand content to the seller terminal; and paying a sale price for the secondhand content to the seller after charging a fee for the secondhand content to the buyer.

Abstract: Disclosed is a method for restricting an additional function of a multifunctional mobile communication terminal according to each terminal in private mobile communication service area. A public/private communication service apparatus stores information of multifunctional mobile communication terminals being provided with the private mobile communication service and information on whether or not each of the terminals is allowed to use the additional function in the public/private shared cell area, and then checks whether or not the located terminal is a terminal being provided with private mobile communication service and whether or not the located terminal is allowed to use an additional function while location registration of a multifunctional mobile communication terminal is proceeding.

Abstract: Disclosed are a method of generating and transmitting a ring back tone and a system thereof. The method of generating a ring back tone in a first terminal based on an internet protocol comprises identifying a type of a network to which a second terminal requesting a call setup belongs, generating ring back tone data to be transmitted to the second terminal according to the type of the network, inserting the ring back tone data into a response message to the call setup, and transmitting the inserted response message to the second terminal.

Abstract: The invention relates to an antenna structure for a portable radio telephone comprising a helical antenna and a rod antenna. The helical antenna is inserted into the portable radio telephone, and the rod antenna is concealed when it is retracted into the telephone. The helical antenna is electrically connected to a Radio Frequency (RF) terminal in the telephone and the rod antenna is electrically connected to a ground terminal in a Printed Circuit Board (PCB) of the telephone to have a dipole structure.

Abstract: The present invention relates to a thermostable enzyme with a 2.1 Å crystal structure of a propeller type comprising six external blades that encompass the outer boundary of the crystal and six internal calcium-binding sites that are embedded inside the above crystal. Each of the six blades comprises 4 or 5 anti-parallel &bgr;-strands, and the six calcium binding sites consist of 3 high-affinity calcium binding sites and 3 low-affinity binding sites, which are involved in the enzyme's thermostability and catalytic activity, respectively. The above-mentioned Ca2+ binding motifs are expected to be utilized in synthesizing highly thermostable proteins and the elucidation of active sites of an enzyme from a three-dimensional structure can help to design new enzymes having those sites with the aid of recent advanced technology of protein engineering.

Abstract: The strain Bacillus sp. DS11 (KCTC 0231BP) is disclosed and a phytase produced by DS11 having the following characteristics: optimum temperature: 65° C.; optimum pH: 7.0; molecular weight: 43,000 dalton; isoelectric point: 5.6; and a specified N-terminal amino acid sequence. The bacterial strain DS11 or the phytase it produces can be used as an animal feed additive.