Abstract: Disclosed are systems and methods that include a thermal desorption unit, a chromatographic column, and an interface device between the unit and the column. The interface device controls the fluid flowing into the column, such as by providing additional carrier gas to maintain a substantially constant gas flow or velocity, by proving a controlled temperature increase, or by venting a portion of the gas received from the thermal desorption unit, thereby removing the dependence on the thermal desorption unit for such control. In some embodiments, the interface is a chromatographic injector. In certain embodiments, a transfer line from the desorption unit is coupled to the same port of the interface device as the chromatographic column. In some of these embodiments, this is accomplished by employing a special adaptor.

Abstract: Interferometric system for the simultaneous measurement of the index of refraction and of the thickness of transparent materials with a single measurement operation. In said system is employed an interferometer as a “shear interferometer” with the advantage of varying the wavelength of the luminous source. The index of refraction and the thickness are determined in two phases. Firstly it is determined the optical path analyzing the displacement of interferometric signal obtained by orthogonal incidence; successively, by means of phase recovery techniques and the previously determined optical path value, it is possible to obtain the index of refraction of the material. From the knowledge of the index and of the optical path it is obtained the material thickness. The system is made up of: a laser source (1), with variable emission wavelength, a collimator (4), a sample (5), a precision rotating base (7), aphotodiode (9), an oscilloscope (10), un bus IEEE-488 (12) ed a PC (11).

Abstract: A multiple access communication network is disclosed having a primary station that is coupled via a transmission medium to a plurality of secondary stations. The primary station is arranged for determining a free channel list comprising the channels, which are not used by any of the secondary stations to transmit information to the primary station. The primary station transmits this list of free channels to the secondary stations. The secondary stations are arranged for attempting to seize one of the channels indicated on the free channel list. If the attempt to seize a channel was successful, the secondary stations keeps using the channel it seized until it has all available information transmitted. If the secondary station stops using the channel, the primary station will include the channel again in the free channel list.

Abstract: In a multiple access communication network a primary station (2) is coupled to a plurality of secondary stations (4 . . . 18). The secondary stations (4 . . . 18) transmit packets to the primary station in timeslots in a frame. These timeslots are chosen according to the DECT standard. The problem is that it is not possible to transmit 53 bytes ATM cells in an efficient way in the standard DECT packets. According to the present invention, the guard space to deal with the differing transmission delays between several secondary stations and the primary station is reduced. To prevent problems due to the above mentioned delay differences, the secondary stations (4 . . . 18) comprise compensation means for adjusting the transmission instants of the packets they transmit. By reducing the guard space, it becomes possible to transmit two 53 bytes ATM cells in a double DECT slot, enabling an efficient transmission of ATM cells over a DECT like frame.

Abstract: In a multiple access communication network a primary station (2) is coupled via a transmission medium to a plurality of secondary stations (4 . . . 18). The primary station is arranged for determining a free channel list comprising the channels which are not used by any of the secondary stations to transmit information to the primary station. The primary station is arranged for transmitting this list of free channels to the secondary ststions.

Abstract: The present invention provides for a network interface for wireless communications involving a mobile terminal (28), the interface comprising a layered protocol structure, including an Internet protocol responsive link layer (40, 52) arranged to be matched to the wireless link.

Abstract: The invention provides signal coding, wherein the signal is source coded to obtain a coded data stream, and source significance information (SSI) is included into the coded data stream, the source significance information (SSI) indicating desired protection rates of respective parts of the coded data stream. In this way, a channel encoder may obtain the source significance information (SSI) from the coded data stream, which is advantageous in presence of intermediate network layers. Preferably, the coded data stream comprises respective packets, the being included in respective headers associated with the respective packets, a given header indicating desired protection rates for respective parts (pin) of the associated packet. In order to provide easy detection of the source significance information (SSI), a first header (SSI1) is placed at a beginning of the coded data stream. Alternatively, the first header (SSI1) is provided with an identifier.