44results about How to "Short relaxation time" patented technology

A dielectric element is formed of a dielectric material exhibiting a magnetic resonance relaxation time, with a relaxation agent incorporated in the dielectric material that reduces the relaxation time of the dielectric material. The dielectric element is adapted for placement on a subject while magnetic resonance data are acquired from the subject, and locally influences the B₁ field distribution in the subject during the acquisition of magnetic resonance data.

A contrast agent for magnetic resonance imaging comprising a complex of a paramagnetic cation, preferably Gd⁺³, Dy⁺³, and Fe⁺³ with three equivalents of a charge neutralizing chelator that provides a lipid soluble complex of the paramagnetic cation is described. The complex is retained intracellularly when introduced into a mammalian cell. A method of providing an image of an internal pathology of a patient by magnetic resonance imaging (MRI) by administering the MRI contrast agent or tagged cells to the patient and scanning the patient using magnetic resonance imaging to obtain visible images of the internal pathology of the patient is also set forth.

In a magnetic resonance method and apparatus for acquisition of an image for examination of a vessel wall variation, a vessel wall section of a patient to be examined is positioned in an imaging volume of the magnetic resonance apparatus, image data of the vessel wall section are acquired with an ultrashort echo time sequence, and an image is generated from the acquired image data.

A method for determining the spatial distribution of magnetic resonance signals from an imaging area, wherein nuclear spins are excited in a spatially encoded fashion through multi-dimensional RF pulses, is characterized in that in a definition step, a resolution grid with resolution grid cells is predetermined, and in accordance with a predetermined phase encoding scheme, an excitation pattern is defined for each phase encoding step, in which the amplitudes within the imaging area are set in accordance with a predetermined distribution identically for each phase encoding step. In a preparatory step, the amplitude and phase behavior of the RF pulses to be irradiated is calculated in accordance with a predetermined k-space trajectory for each defined complex excitation pattern.

A dielectric element for positioning on an examination subject for locally influencing the B1 field distribution during magnetic resonance data acquisition contains a relaxation agent bound to mutually separated particles. The relaxation agent incorporates a paramagnetic substance. In a corresponding method for acquiring magnetic resonance data from an examination subject, such a dielectric element is positioned on the examination subject for locally influencing the B₁ field distribution, by homogenizing the B₁ field of a magnetic resonance apparatus.

An ethylene-α-olefin copolymer wherein the copolymer has a monomer unit based on ethylene and a monomer unit based on an α-olefin having 3 to 20 carbon atoms, the density (d) is 860 to 950 kg/m³, the melt flow rate (MFR) is 1 to 100 g/10 min, the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 4 to 30, the ratio (Mz/Mw) of the Z average molecular weight (Mz) to the weight average molecular weight (Mw) is 2 to 5, the swell ratio (SR) is 1.8 or more, and the characteristic relaxation time (τ) obtained by linear viscoelasticity measurement is 0.01 to 10 seconds.

The invention relates to a preparation method of self-repair thermosetting epoxy resin based on disulfide bond exchange. The method is characterized in that a disulfide bond-containing epoxy monomer is prepared through a two-step reaction, and the disulfide bond-containing epoxy monomer and a multi-amine monomer are subjected to a ring-opening crosslinking reaction under solvent-free condition toobtain the thermosetting epoxy resin containing the disulfide bond. The disulfide bond is subjected to an exchange reaction while being heated, so that the cured epoxy resin has certain plasticity while being heated, realizes self restoration and repeated processing, and solves the disadvantages of difficult restoration and one-time moulding. The epoxy resin has good degradation characteristic ina mercaptan system due to an exchange reaction of the disulfide bond and a sulfhydryl group, and solves the problem of environment pollution due to excessive usage of the thermosetting epoxy resin.

The invention provides the structure of a quantum cascade detector, which comprises a substrate, a lower ohmic contact layer, a barrier isolation layer, a multi-cycle active region structure layer, an upper ohmic contact layer, an upper electrode and a lower electrode, wherein the lower ohmic contact layer is arranged on the substrate and is used for carrying out the high-concentration doping process to achieve the ohmic contact with electrode materials; the barrier isolation layer is arranged at the middle part of the lower ohmic contact layer to form a table top all around the lower ohmic contact layer, wherein the barrier isolation layer is not doped; the multi-cycle active region structure layer is arranged on the barrier isolation layer and constitutes the core part of the detector for detecting light current; the upper ohmic contact layer is arranged on the multi-cycle active region structure layer and is used for carrying out the high-concentration doping process to achieve the ohmic contact with the electrode materials; the upper electrode is prepared on the upper ohmic contact layer; and the lower electrode is prepared on the table top all around the lower ohmic contact layer.

The invention provides a capacitive magnetic field intensity sensor based on magnetic liquid drips. The capacitive magnetic field intensity sensor is applicable to precise measurement on a high-frequency tiny magnetic field. The capacitive magnetic field intensity sensor comprises a positive electrode wiring port (1), a negative electrode wring port (2), a capacitive positive electrode plate (3),a capacitive negative electrode plate (4), magnetic liquid drips (5), sealed air (6) and a sealed cavity (7). The magnetic liquid drips (5) are soft magnetic materials, have superparamagnetism, and have ultrashort relaxation time; when an external magnetic field exists, the magnetic liquid drips (5) instantly form the peak, so that the dielectric constant of media between the capacitive positive electrode plate (3) and the capacitive negative electrode plate (4) changes; the capacitance change is further caused; after the magnetic field is eliminated, the magnetic liquid drips (5) return to the bottom of the sealed cavity (7); capacitance also returns to an initial value; and the relaxation time of the magnetic liquid drips (5) is very short, and residual magnetism and coercive force do not exist, so that the precise measurement on the high-frequency tiny magnetic field is realized.

The invention provides a multifunctional sensing integrated flexible fabric-based sensor and application thereof. The multifunctional sensing integrated flexible fabric-based sensor is obtained by interweaving and integrating three sets of mutually independent warp yarn and weft yarn systems through a weaving technology, wherein the three sets of mutually independent warp yarn and weft yarn systems are respectively formed by three kinds of yarns with different sensing functions; the three sets of mutually independent warp and weft systems are respectively a warp and weft system formed by yarns with a pressure sensing function, a warp and weft system formed by yarns with a temperature sensing function and a warp and weft system formed by yarns with a humidity sensing function. The multifunctional sensor is constructed from three structural dimensions of fiber, yarn and fabric, is used for realizing a large-area accurate sensing function of pressure, temperature and humidity, has excellent flexibility and anti-interference performance, and can accurately and independently sense different signals and integrate the signals through anti-interference processing. The sensor has a huge application prospect in the fields of wearable flexible electronic devices and the like.

The invention discloses an overmoded high power pulse detector. A hot carrier effect of a strong electric field in a semiconductor is taken as a basic working principle, and measurement is realized according to resistance variation of the semiconductor. The detector comprises a WR2.8 standard waveguide with a smaller outlet surface, a WR2.8-WR8.0 transition waveguide with an outlet surface changing from small to large, a WR8.0 standard waveguide with a relatively larger outlet surface, a semiconductor detection chip and a matching load at the rear end. The peak power which can bear a pulse can reach 100 W, the response speed is smaller than 1 ns, and the difficulty in detection chip processing and detector integration is relatively smaller. The detector is suitable for high power pulse measurement in a frequency range of 0.3-0.4 THz.

The invention relates generally to the treatment of skin using laser light, and more particularly to a non-invasive device and method for such treatment. During skin treatments, heating of the epidermis is undesired because it may cause discomfort for the person being treated, adverse skin reactions and unwanted changes in skin pigment. The invention provides a laser treatment beam having a first 22a and a second 22b beam region of non-zero light intensity disposed at a periphery of a transverse cross-section of the beam, and a third beam region 22c, arranged between the first 22a and the second 22b beam region, of lower light intensity than said non-zero light intensity. The treatment beam 22 exits the device 10 along its optical treatment axis 13. As the treatment beam 22 passes through an outer layer of the skin to the focal spot 25 along the optical treatment axis (13), the extent of the third beam region 22c is predetermined and/or controlled so as to provide a corresponding third skin region 23c in the outer skin layer 16, arranged between the first 23a and the second skin region 23b, and the lower light intensity of the third beam region is predetermined and/or controlled to provide a maximum temperature during a pulse of the laser treatment beam with in the third skin region 23c which is lower than the maximum temperatures during said pulse of the laser treatment beam within the first 23a and the second 23b skin region. The light source 20 is configured and arranged to provide, in use, a pulse duration of the pulse of the laser treatment beam which is longer than the thermal relaxation time of the first 23a and the second 23b skin region. By predetermining and/or controlling the dimensions of the third skin region 23c, a suitably dimensioned heat sink is created, centrally located within the region being heated by the laser treatment beam, and used to avoid temperature hot spots in the outer layers of the skin.

An eductor suitable for use in an assembly for preparing a liquid product comprises a housing having a substantially cylindrical wall. The eductor comprises an injector valve which is displaceably arranged within the cylindrical wall from first position to a second position longitudinally spaced from the first position, and vice versa. On its outer surface the injector valve comprises two annular protrusions which are spaced from each other, each of the annular protrusions engaging the inner surface of the cylindrical wall for forming a seal therewith, said annular protrusions together with the inner surface of the cylindrical wall forming an annular chamber, said protrusions being arranged for isolating the annular chamber from fluid communication with any environment outside the annular protrusions when said injector valve is positioned in the first position or the second position or any position in between.

The invention discloses a piston type internal combustion engine for quickly passing through dead point through magnetic boosting. The piston type internal combustion engine comprises a cylinder, a piston, a connecting rod and a crank, wherein the end, hinged to the crank, of the connecting rod is provided with a magnet I; the connecting line of the N pole and the S pole of the magnet I is perpendicular to the connecting rod and is positioned in the plane of rotation of the crank; the inner wall of the cylinder is also provided with a pair of magnets II; when the connecting rod and the crank are collinear and the connecting rod is positioned at the position of an upper dead center, the pair of magnets II is positioned on the two sides of the magnet I and the connecting line of the pair of magnets II is collinear with the connecting line of the pole N and the pole S of the magnets I; when the polarities of the magnetic poles, on the side opposite to the magnet I, of the magnets II are the same and the crank starts to rotate from the upper dead center, the magnetic pole, on the same side as the linear speed direction of the crank, of the magnet I is reverse to the polarity of the magnetic pole of the oppositely arranged magnet II. The piston type internal combustion engine has a simple structure, and the relaxation time at the dead center is shortened, so that the purpose of improving the efficiency by shortening the energy consumption time as much as possible is achieved.

The invention discloses a high-precision calibration device and method for a thin film type heat flow meter. A direct-current constant-voltage power supply in a heating system ensures that polyimide electric heating films output stable heating power; constant-temperature water cavities in a cooling system are connected with a temperature-adjustable cooling water circulating machine by pipes to ensure a constant cooling temperature; a Keithley multichannel data collector in a data acquisition system realizes thermoelectric signal conversion, and computer software records and stores temperatureand potential data. In the calibration device, the polyimide film is hollowed according to the shape of the heat flow meter to reduce the contact surface air gap and the contact thermal resistance; flexible regulation and control of the working temperature of to-be-calibrated heat flow meters are achieved by adjusting the heating power and cooling circulating water temperature and arranging mica sheets, high-heat-conductivity aluminum foils are pasted on the heat surface of the heat flow meter and the two sides of an electric heating film to promote uniform heat transfer, and heat preservationcotton is arranged around a test piece to reduce experimental errors caused by natural convection. The experimental device is good in matching, simple and convenient to operate and capable of achieving rapid and high-precision calibration of the thin film type heat flow meter.

The present invention provides a scanning electron microscope probe current detection device and a scanning electron microscope. When a scanning unit is in a forward scan stage, a deflection unit controls an electron beam not to deflect, a detection circuit does not carry out the sampling operation of the electron beam, at this time, the electron beam passes a lens cone normally to irradiate to the surface of a sample, thereby realizing the sample imaging. When the scanning unit is in a flyback stage, the deflection unit controls the electron beam to deflect, the detection circuit carries out the sampling operation of the electron beam, so that a numerical value of a probe current is obtained. The whole process does not need to move a sample bench completely. The electron beam does not participate in the imaging in the flyback stage, so that the image acquisition of the scanning electron microscope is not interrupted when the probe current is detected in the flyback stage, the change of the probe current is detected real-timely while the electron microscope images are acquired, and the probe current detection is finished efficiently. Meanwhile, the probe current detection does not need to move the sample bench, so that the precision requirement of the sample bench can be reduced.