Abstract:
Provided is a frequency-tunable terahertz light source device. The frequency-tunable terahertz light source device satisfies a Littrow diffraction condition at a wavelength and simultaneously satisfies a Littman-Metcalf diffraction condition at another wavelength using a double diffraction grating having two grating periods. Thus, oscillations simultaneously occur at the two different wavelengths, such that a terahertz wave can be stably generated by beating of the two oscillation wavelengths. In addition, the frequency-tunable terahertz light source device can readily change a frequency up to several terahertz and can be fabricated in a small size.
Abstract:
An electronic business transaction system is provided. The electronic business transaction system requests an ordering party to select an electronic business and input order information for the electronic business through a terminal of the ordering party, receives the order information for the electronic business from the ordering party, announces a bid for the electronic business, requests bidders to select the electronic business, input bid information for the electronic business, and organize execution groups for the electronic business through a terminal of the bidders, receives the bid information and information for the execution groups from the bidders, analyzes the bid information and the information for the execution groups, selects an order-taking party from among the bidders according to the results of the analysis, concludes an electronic contract for the electronic business between the order-taking party and the ordering party, and provides an application for processing the electronic business regarding the electronic contract to terminals of execution group members belonging to an execution group of the order-taking party so that the execution group members process the electronic business through the terminals of the execution group
Abstract:
A driving system that can allow a vehicle to go over or ascend obstacles or stairs through a step driving manner is provided. The driving system includes a power transmission unit connected to a main shaft connected to a power generation unit installed on the wheel frame, a plurality of driven units engaged with the power transmission unit and supporting wheels rotating by rotational force of the power transmission unit, and a carrier to which the power transmission unit and each of the driven units are operationally fixed and which goes over the obstacles by rotating when the driven units stop due to the obstacles.
Abstract:
Provided are a superluminescent diode with a high optical power and a broad wavelength band, and a method of fabricating the same. The superluminescent diode includes: at least one high optical confinement factor (HOCF) region; and at least one low optical confinement factor (LOCF) region having a lower optical confinement factor than the HOCF region. The method includes obtaining a difference of optical confinement factors in the HOCF region and the LOCF region through a selective area growth method, the selective area growth method using a deposition thicknesses difference of thin layers according to a width difference of openings that expose a substrate.
Abstract:
Articles are disclosed, comprising a polymer foam layer having a first surface and an opposite second surface; a plurality of cells between the first surface and the opposite second surface of the polymer foam layer, wherein the thickness of the polymer foam layer between the first surface and the opposite second surface is 1.0 to 1.5 times the average height of the plurality of cells; and a plurality of magnetic, electrically conductive particles aligned into a plurality of mutually isolated chains that essentially continuously span the foam between the first surface and the opposite second surface of the polymer foam layer. The foams are useful as gaskets for electromagnetic shielding, grounding pads, battery contact conductive spring elements, and the like.
Abstract:
Provided is a bi-directional optical module including: a transmission optical element including an SOA (semiconductor optical amplifier) aligned on an optical axis of an LD (laser diode) formed on a substrate; and a reception optical element comprising a PD (photodiode) including a light receiving surface perpendicular to the optical axis of the LD of the transmission optical element.
Abstract:
An antenna configured for low frequency applications on a mobile device includes an antenna element coupled to a conductive structure which, in turn, is coupled to the user of the mobile device such that the user of the mobile device effectively becomes part of the antenna. The conductive structure can include, for example, the device housing being made from a conductive material, a conductive structure embedded inside the device housing, or conductive pads exposed in the device housing. The antenna element is electrically connected to the conductive structure and the user can be coupled to the conductive structure either through direct contact or through capacitive coupling. In addition, the antenna can include an active element configured to boost free space operation efficiency. The active element can include, for example, a low noise amplifier integrated onto a low noise amplifier board. The active element can be at least partially surrounded by a hollow support structure around which an antenna coil is wrapped, where the antenna coil is coupled to the active element. Furthermore, one or more antenna coils can be utilized either separately or in conjunction with the antenna for low frequency applications, where the one or more antenna coils can have integrated therein inductive components and/or active/switching elements that allow the one or more antenna coils to be tuned to a desired frequency.
Abstract:
Provided is a semiconductor laser including a substrate etched into a mesa structure, an active layer, clad layers, a current blocking layer, an etch-stop, an ohmic contact layer, and electrodes, and a method for manufacturing the same, whereby it is possible to improve a ratio of light output to input current by blocking a leakage current flowing outside an active waveguide in a BH laser.
Abstract:
Disclosed is a wheel chair capable of going over an obstacle or ascending or descending a stair. The wheel chair comprises a wheel frame; an actuator coupled to the wheel frame; a power generating unit coupled to the actuator; a first transmission having a sun gear fixed to the power generating unit, a plurality of planet gears meshed with the sun gear, a ring gear meshed with the respective planet gears, and carriers coupled to the respective planet gears; a second transmission having a driving shaft meshed with the ring gear, a key frame rotatably installed on the driving shaft, and a casing fixed to the key frame; a plurality of front wheels each coupled to the driving shaft; a follower drivingly coupled to the driving shaft and having a follower shaft; and a rear wheel fixed to the follower shaft.