Abstract: The present invention relates to a communications system (1) for making multimedia calls. The system comprises two multimedia terminals (10,12) and communication means for making a multimedia call over a shared communications network (20), including a firewall (26) through which the multimedia call must pass, and which restricts certain types of communication. Each terminal (10,12) has a number of logical communication ports for the multimedia call, including at least one dynamically assigned port. In the course of setting up the multimedia call, at least one of the terminals (10,12) is adapted to send a request to the other of the terminals to open up one or more of the dynamic ports in the other terminal. The system includes a proxy server (40) between the terminals (10,12) that acts for each terminal as a proxy for the other terminal during the course of the call. The proxy server (40) has logical communication ports for communication with the terminals including one or more pre-assigned ports.

Abstract: The present invention relates to a communications system (1) for handling communications sessions, for example multimedia calls or voice calls. The communications system (1) comprises a local terminal (10), an external server (40), a proxy interface agent (PIA) (11) between the terminal (10) and a shared network (20). The communication means includes a NAT function (32) through which the communications session must pass. The communications session is carried over the network (20) over one or more logical channels between the terminal (10) and the external server (40), during which the first NAT function (32) applies network address mappings on the terminal's transport addresses (14). The PIA (11) acts on behalf of the terminal (10) in communications with the external server (40), and establishes a logical channel on an outbound connection to the server that serves as a control channel between the PIA (11) and the server (40).

Abstract: A method for calibrating thermal resistance and thermal capacitance parameters characterizing a DSC cell, and then calculating the heat flow to the sample based upon the results of the calibration. The method is applied in a conventional heat flux calorimeter, to obtain thermal analysis data having improved baseline and resolution. A first embodiment is based upon a model of a calorimeter in which there is no cross-talk between the sample and reference sides of a DSC cell. The thermal resistance and thermal capacitance parameters are calculated by carrying out a sequential series of calibration measurements with an empty DSC cell, materials on the reference side and materials on both the sample and reference sides. Another embodiment takes the existence of cross-talk between the sample and reference sides of the calorimeter into account.

Abstract: A method for using a neural network to deconvolute the effects due to surface topography from the effects due to the other physical property being measured in a scanning probe microscopy (SPM) or atomic force microscopy (AFM) image. In the case of a thermal SPM, the SPM probe is scanned across the surface of a sample having known uniform thermal properties, measuring both the surface topography and thermal properties of the sample. The data thus collected forms a training data set. Several training data sets can be collected, preferably on samples having different surface topographies. A neural network is applied to the training data sets, such that the neural network learns how to deconvolute the effects dues to surface topography from the effects dues to the variations in thermal properties of a sample.

Abstract: A platinum/Rhodium resistance thermal probe is used as an active device which acts both as a highly localized heat source and as a detector to perform localized differential calorimetry, by thermally inducing and detecting events such as glass transitions, meltings, recystallizations and thermal decomposition within volumes of material estimated at a few &mgr;m3. Furthermore, the probe is used to image variations in thermal conductivity and diffusivity, to perform depth profiling and sub-surface imaging. The maximum depth of the sample that is imaged is controlled by generating and detecting evanescent temperature waves in the sample.

Abstract: Sub-micron chemical analysis of the surface and sub-surface of a sample material is performed at, above or under atmospheric pressure, or on for a sample material submerged in a substance. A thermal and/or topographic image of the surface of the sample material is obtained. A location for study is selected using the image. The activation device is positioned over the selected location and surface and/or sub-surface products are ablated, desorbed or decomposed from the sample material to a chemical analyzer for analysis.

Abstract: A sample and a scanning probe microscope system are used as the detector for an infrared spectrometer to circumvent the diffraction limit of conventional infrared microscopy, and to provide spectroscopic images with a greatly improved spatial resolution, potentially as low as a few tens of nanometers. The beam from an infrared spectrometer is directed at the sample. The sample is heated to the extent that it absorbs infrared radiation. Thus the resulting temperature rise of an individual region depends upon the particular molecular species present, as well as the range of wavelengths of the infrared beam. These individual temperature differences are detected by a miniature thermal probe. The thermal probe is mounted in a scanning thermal microscope. The scanning thermal microscope is then operated used to produce multiple surface and sub-surface images of the sample, such that the image contrast corresponds to variations in either thermal diffusivity, surface topography or chemical composition.

Abstract: A system and method for performing localized mechanothermal analysis with scanning probe microscopy (“MASM”) is disclosed. In a preferred embodiment an image of the surface or subsurface of a sample is created. A localized region of the sample is selected from the image. Using a scanning microscope, an active or passive thermal probe is positioned at the selected region. A temperature ramp is applied to the localized region. In addition, a dynamic or modulated stress or strain is applied to the localized region. Force data resulting from the applied temperature and stress or strain is collected and processed to produce a graph or fingerprint of the dynamic mechanical and/or calorimetric properties of the selected localized region.

Abstract: A platinum/Rhodium resistance thermal probe is used as an active device which acts both as a highly localized heat source and as a detector to perform localized differential calorimetry, by thermally inducing and detecting events such as glass transitions, meltings, recystallizations and thermal decomposition within volumes of material estimated at a few .mu.m.sup.3. Furthermore, the probe is used to image variations in thermal conductivity and diffusivity, to perform depth profiling and sub-surface imaging. The maximum depth of the sample that is imaged is controlled by generating and detecting evanescent temperature waves in the sample.

Abstract: A temperature alarm system includes a temperature sensing module and an alarm circuit that are powered by a photocell and a battery that is charged by the photocell. The photocell normally provides enough power to operate the system and charge the battery. When the temperature sensing module senses a temperature that exceeds a predetermined alarm limit, it generates an alarm signal which activates an alarm circuit that generates a visual and/or audible alarm either immediately after the alarm signal is generated, or after the alarm signal has been generated for a period of time. The generation of the alarm signal and/or the alarm causes the system power consumption to increase, so the system begins to draw power from the battery. After the alarm condition is corrected, the system returns to normal power consumption, and the photocell provides enough power to operate the system and charge the battery.

Abstract: A modulated differential scanning calorimeter ("MDSC") wherein the temperature of the sample and/or the reference is modulated by modulating the characteristics of a gas in thermal contact with the sample and or a reference. In a first embodiment, the major heat flow path between the sample/reference and the furnace is the purge gas in the furnace chamber. The composition of the purge gas in the furnace chamber of the DSC cell is modulated by alternately purging the DSC cell with a high thermal conductivity gas (e.g., helium) and with a low thermal conductivity gas (e.g., nitrogen), thus modulating the flow of heat to and from the cell. In a second embodiment, the sample and reference are heated (or cooled) by a temperature-controlling gas flowing around the sample and reference holders. The gas is heated by being passed through a furnace before it flows around the sample and the reference.

Abstract: A resilient snap fitting retainer provides a desired retention force despite tolerance variations. A pair of parallel resilient legs extends from a base. The legs are separated by a gap. A deformable rib is provided on at least one of the legs to partially crush when the legs are compressed with sufficient force. The partial crushing compensates for tolerance variations in the size of an opening into which the retainer is inserted or in the size of the retainer itself. The legs are elongated and terminate in wedge shaped feet at their distal end. The feet form a generally arrowhead-like shape for insertion into an opening. The structure of the feet and legs enables the legs to deflect toward each other (i.e., buckle) after the interior surfaces of the legs have made contact at their distal ends as the feet are pushed through the opening.

Abstract: The interpretation of dynamic differential calorimetry ("DDSC") data is enhanced by parsing the data according to whether it is obtained while the sample is being heated, cooled, or re-heated. Each DDSC scan is split up into three separate components, depending upon whether the sample is undergoing heating, cooling or reheating. Each component can then be analyzed separately to investigate the sample response to temperature change as the sample is being heated, cooled, or re-heated. Each file is deconvoluted separately, using a deconvolution routine that first removes the effect of the phase lag due to the instrument's finite response time.

Abstract: The present invention is a modulated differential thermal analysis technique for determining the composition, phase, structure, identification, or other properties of a material that undergoes a transition as function of temperature or other driving variable. As applied to differential scanning calorimetric analysis (DSC), the preferred embodiment comprises (1) heating a sample of the material with a linear temperature ramp that is modulated with a sinusoidal heating rate oscillation; (2) simultaneously heating a reference at the same linear temperature ramp; (3) measuring the differential temperature of the sample and reference; and (4) deconvoluting the resultant heat flow signal into rapidly and non-rapidly reversible components.

Abstract: The present invention relates to differential analytical techniques for determining the composition, phase, structure, identification or other properties of a material that undergoes a transition as function of a driving variable. As applied to differential scanning calorimetric analysis (DSC), the preferred embodiment comprises: (1) heating a sample of the material with a linear temperature ramp that is modulated with a sinusoidal heating rate oscillation; and (2) deconvoluting the resultant heat flow signal into rapidly reversible and non-rapidly reversible components.

Abstract: A method and apparatus for measuring the thermal conductivity of materials using modulated differential scanning calorimetry (MDSC). Two MDSC heat capacity measurements are made consecutively. One measurement is made under conditions which ensure obtaining a fairly accurate value for the heat capacity of the material ("quasi-ideal conditions"). Another measurement is made under conditions such that the measured effective heat capacity differs from the accurate value of the heat capacity due to thermal conductivity effects. Generally, the non-ideal conditions differ from the ideal conditions by one parameter, such as the size of the sample, the modulation frequency used to measure the heat capacity, or, for thin films, the presence or absence of a specimen on the thin film. The thermal conductivity of the material is then calculated from the difference between the heat capacity measured under quasi-ideal conditions and the effective heat capacity measured under non-ideal conditions.

Abstract: A method of forming a branch-off seal between a heat-shrinkable sleeve and at least two spaced-apart elongate substrates, which comprises the steps of:(a) positioning the substrates within the heat-shrinkable sleeve;(b) positioning between the substrates and within the sleeve at an open end thereof a plug having a larger cross-sectional size at a first position away from said open end and a smaller cross-sectional size at a second position towards said open end;(c) positioning a heat-activatable sealing material at the first position;(d) shrinkable conduits in the sleeve by positioning one or more clips at the open end of the sleeve such that the substrates and the plug are in respective conduits; and(e) while the clip remains on the sleeve, applying heat so as to affect shrinkage of the sleeve to activate the sealant, and form the desired seal.

Abstract: The present invention is a spatially-resolved differential analysis technique. A modulated differential analysis technique is applied using a proximal probe to obtain a spatially resolved characterization of a heterogeneous sample comprising at least two phases. As applied to spatially-resolved modulated differential scanning calorimetry, the present invention comprises a thermocouple probe that is scanned over the sample surface. The differential temperature of the area of the sample just beneath the thermocouple probe is obtained with respect to the temperature of a reference. The temperature of the sample and the reference is modulated above and below a transition temperature for one phase of the sample. The signal from the thermocouple probe is deconvoluted to obtain an image of the sample delineating the regions of the sample having that phase.

Abstract: The present invention relates to differential analytical techniques for determining the composition, phase, structure, identification or other properties of a material that undergoes a transition as function of a driving variable. As applied to differential scanning calorimetric analysis (DSC), the preferred embodiment comprises: (1) heating a sample of the material with a linear temperature ramp that is modulated with a sinusoidal heating rate oscillation; and (2) deconvoluting the resultant heat flow signal into rapidly reversible and non-rapidly reversible components.