167 results about "Field uniformity" patented technology

The invention provides a microwave anechoic chamber performance measuring method, which comprises the following steps of: adopting a microwave anechoic chamber performance measuring system, and setting a dead zone parameter, a measuring frequency, a signal source power, a scanning trace and a kinematic velocity of a receiving antenna, and a rotation direction and a rotation velocity of a transceiving antenna according to the requirements of a microwave anechoic chamber performance analysis test; driving a signal source according to the signal source power; driving each stepping motor to control each moving part to move according to the scanning trace and the kinematic velocity of the receiving antenna, and the rotation direction and the rotation velocity of the transceiving antenna; and controlling a signal receiver to receive a signal of the receiving antenna according to the measuring frequency, and storing the signal. The method can be adopted to be applied in a microwave anechoic chamber flexibly so as to measure along different scanning traces; and a computer is adopted to realize automatic measurement of microwave anechoic chamber dead zone reflectivity level, cross polarization character, multi-path loss uniformity, and field uniformity performance indexes, so that the measuring efficiency is improved.

The invention provides an anechoic chamber performance measurement system which comprises testing racks and control devices. The testing racks comprise a transmitting antenna rack used for lifting and rotating a transmitting antenna, a receiving antenna rack used for moving and rotating the receiving antenna in a three-dimensional space. The control devices comprise a processor, a laser distance measuring sensor, a steeping motor which controls movement of all parts in the testing racks, a signal source and a signal reception device. The anechoic chamber performance measurement system can be applied to measurement of the anechoic chamber along different scanning traces. Automatic measurement of anechoic chamber dead zone reflectivity level, cross polarization character, multipath loss uniformity and field uniformity performance index are achieved by using automatic control, automatic measurement and automatic storage measuring data of a computer. Measurement efficiency is improved, and measurement accuracy is high.

A method for accessing aircraft interference path loss in an aircraft. A plurality of radio frequency signals that are stepped through a plurality of frequencies in a frequency range is transmitted from a plurality of locations within an interior of the aircraft. Radio frequency signals present at a receive antenna are received in response to transmitting the plurality of radio frequency signals to form a plurality of measurements. An average of averages curve is generated from the plurality of measurements. A peak to average ratio is identified. Field uniformity is identified. A standard error for the average of averages curve is determined. An upper bound for the aircraft interference path loss in the aircraft is predicted using the average of averages curve, the peak to average ration, the field uniformity, and the standard error.

Simplicity of design is achieved for an electrohydrodynamic microfluidic mixer by applying an electric field substantially transverse to the flow direction and substantially orthogonal or normal to the interfacial plane between the fluids being mixed in the main channel. The electric field is wide enough to encompass substantially the entire depth of the main channel in the microfluidic mixer. In one exemplary embodiment, the electrohydrodynamic microfluidic mixer comprises a substrate, one main channel disposed on the substrate, first and second inlet channels disposed on the substrate and individually coupled to the main channel, and first and second electrodes disposed on opposite sides of the main channel for applying an electric field across the main channel substantially transverse to the flow direction in the main channel. Field uniformity across the desired cross-section of the main channel is achieved by having the electrode thickness be substantially equal to the main channel depth. Disposition of the electrodes is judiciously controlled to generate the electric field in a direction substantially orthogonal or normal to the interfacial plane between the fluids in the main channel.

Interlaced-to-progressive conversion with (1) 3-2 pulldown detection, (2) pre-filtering for field motion detection, (3) field motion detection with feedback, (4) field edge detection including direction angle detection by comparison of pixel differences with sets of more than pairs of pixels and a lateral edge detection probability by a lack of non-lateral angle detection, and (5) blending moving pixel interpolation and still pixel interpolation using field uniformity.

The invention relates to a method for preparing a high-quality large silicon carbide single crystal and a silicon carbide single crystal prepared by the method. The method comprises the following steps: placing a seed crystal on a seed crystal frame coated with a carbon-enriched polymer and heating so that the carbon-enriched polymer is thermocured; heating in an inert atmosphere so that the carbon-enriched polymer is pyrolyzed and carbonized; and growing the silicon carbide crystal on the carbonized and bonded seed crystal by a seed crystal guide gas phase transport technology (PVT). The seed crystal and the seed crystal frame are tightly bonded by the carbon-enriched polymer and pyrolyzed and carbonized after being cured to form a dense middle carbon layer, thereby effectively improving the temperature field uniformity of the silicon carbide seed crystal and solving the problems of polycrystals, multinuclear intergrowth, multiform mixture, and the like caused by uneven temperature distribution; the growing silicon carbide crystal has a single crystal form, the size of the crystal is larger than 2 inches, and the n-type or p-type mixed silicon carbide crystal can be prepared by mixing impurities in the growing process of the seed crystal.

An integrated solid-state lamp comprised of thermally conducting materials such as alumina ceramic or graphite filled polymers may simultaneously perform optical operations on the light emerging from solid-state emitters to enable the creation of a lamp which produces light in both direct and indirect light zones with a near-field uniformity more comparable to that produced by a vertical filament incandescent lamp. The light chamber structures may incorporate optical light path modifiers which push light into additional lighting zones for proximately omnidirectional light. Diffuser structures may incorporate hole patterns to improve thermal flow and light recycling efficiency. The distribution produced fully encompasses 0-180 deg. Light produced by the lamp chambers or atrium serve in like manner to the atrial chambers of the heart to produce light uniformly in all directions for general illumination at high efficiency.

Direct and indirect electron bombardment provide a sufficiently high degree of temperature uniformity across the emitting surface of a large-area electron source for an electron beam projection system such that a broad beam having illumination uniformity within 1% can be achieved. A diode gun is used to obtain extraction field uniformity and maintain uniformity of illumination. Power requirements and power dissipation in beam periphery truncating apertures is reduced by roughening the surface of a monocrystalline cathode or depositing materials having a higher work function thereon.

Disclosed are a source stirring electromagnetic reverberation chamber and a stirring method thereof. The reverberation chamber includes an electromagnetic shielding chamber, a source stirring device installed on the side wall of the electromagnetic shielding chamber, and the source stirring method used for describing installation, motion and control method of an transmitting antenna. Simultaneous change of the position and polarization direction of the transmitting antenna is realized through control of a rotating shaft to rotate. A drive device of the rotating shaft is installed at the outer side of the reverberation chamber and the rotating shaft which is installed on the inner wall of the reverberation chamber is driven to rotate through a changeover mechanism. The reverberation chamber realizes field uniformity in the reverberation chamber through rotation of a single antenna so that space utilization rate in the reverberation chamber is effectively improved and a source stirring reverberation chamber of the same volume can realize a larger test area; relative to an EUT of the same size, a source stirring reverberation chamber which is smaller in volume can be designed so that generation of high field intensity is better facilitated; and the reverberation chamber is also applicable to a condition in which a plurality of transmitting antennae are configured in a reverberation chamber to carry out source stirring.

The invention relates to a device for improving the temperature field uniformity of a crystal growing furnace of a physical vapor transport method. The device comprises the crystal growing furnace. The crystal growing furnace comprises a radio frequency power supply, a contact electrode, a coil, a heat preservation layer and a graphite crucible. The coil is uniformly distributed outside the heat preservation layer in a horizontal axis symmetry mode. In addition, the coil can rotate around the heat preservation layer by rotating the device. The temperature field uniformity of the growing furnace is improved by changing the coil winding mode around the growing furnace, the coil can be formed by winding one or more wires, it is ensured that the coil is distributed around the growing furnace in the horizontal axis symmetry mode, and the large growing furnace axial temperature gradient caused by spiral distribution of the coil can be easily reduced. In addition, the radio frequency power supply is connected with the coil in a free contact mode, the coil can rotate around the growing furnace, the growing furnace is uniformly heated in a three-dimensional mode, and the temperature field uniformity of the growing furnace is improved.

The invention provides a mixing stirring device of mechanical stirring and source stirring of an electromagnetic reverberation chamber. The mixing stirring device comprises the electromagnetic reverberation chamber and further comprises a mechanical stirring assembly and a source stirring assembly, wherein the mechanical stirring assembly and the source stirring assembly are arranged on the side wall of the electromagnetic reverberation chamber. The mechanical stirring assembly comprises a first motor and a mechanical stirrer connected with the first motor; the source stirring assembly comprises a second motor, a rotary shaft connected with the second motor and a transmitting antenna disposed on the rotary shaft. By means of combination of a mechanical stirring device, a source stirring device and a method, change of electromagnetic field distribution in the reverberation chamber depends on more variable changes which include changes of the length, the width and the height of an equivalent reverberation chamber and changes of the position of an excitation current source or/and orthogonal coordinate components of current density, and therefore more choices are provided for further improving field uniformity of a testing area in the reverberation chamber so that performance of the reverberation chamber is more likely to be improved.

The invention discloses a calibrating method and a calibrating system for field uniformity of a transient electromagnetic field. The method comprises the steps of: selecting a reference point and a plurality of measuring points in an area to be calibrated, wherein the reference point is different from the measuring points in position; for each measuring point, measuring the electromagnetic field of the measuring point and the reference point simultaneously to respectively obtain the field intensity value of each measuring point and the reference field intensity value corresponding to the measuring point; calculating the normalized field intensity value of the measuring point according to the field intensity value of each measuring point and the reference field intensity value corresponding to the measuring point; and obtaining the field uniformity of the transient electromagnetic field in the area to be calibrated according to the normalized field intensity values of all measuring points. The system comprises an oscilloscope, a first probe and a second probe. The first and second probes are connected electrically with the oscilloscope. The method and the system have low requirements on a transient electromagnetic field generator comprising a pulse signal source and can calibrate the field uniformity of the transient electromagnetic field rapidly and accurately.

The invention provides a flow mixing device, which belongs to the technical field of SCR denitration of a coal-fired boiler of a thermal power plant, The flow mixing device comprises a swing flow deflector, comprising a first flow deflector and a second flow deflector which are arranged on two sides of a flue center line as well as are respectively and rotatably connected with a flue side wall, aflue is divided into several sub-flues by the first flow deflector and the second flow deflector; and an angle adjusting mechanism is respectively connected to the first flow deflector and the secondflow deflector for driving the first flow deflector or the second flow deflector to rotate. The invention also provides a SCR denitration system and a denitration system flue flow field homogenizationmethod. The flow mixing device, the SCR denitration system and the SCR denitration system flue flow field homogenization method solve the technical problem that the installation and fixing of the flow deflectors in the flue flow field cannot guarantee the uniformity of the flow field in the prior art.

The invention provides a packaging system and a packing method for a sealed glass packaging body through a laser. Laser emitted from the laser is projected to a to-be-packaged sealed glass packaging body through a laser scanning unit for heating the to-be-packaged sealed glass packaging body; the laser can rapidly and periodically scan for realizing a quasi-synchronous packaging effect and for fulfilling the purpose of achieving high temperature field uniformity and high productivity; meanwhile, the diversified packaging patterns are realized; further more, a portal frame can be provided with one or more laser scanning units, and the portal frame can drive the laser scanning units to move in a stepping manner for performing regional packaging for the large-sized to-be-packaged sealed glass packaging body, or for packaging multiple to-be-packaged sealed glass packaging bodies at the same time, so that the productivity is greatly improved.

The invention relates to a method for fabricating a gradient coil of a superconducting magnetic resonance imaging device, which comprises the following steps of: (1) cutting a fingerprint-shaped coil from a copper plate by a cutter; (2) taking the coil from the copper plate, washing and air-drying the coil; (3) spraying a resin on the coil surface; and (4) cementing the coil sprayed with the resin to an epoxy plate and pressing the epoxy plate so that the coil is fixedly shaped with the epoxy plate, wherein the coefficient of heat conductivity of the resin is 1W/(m.K). The invention has the beneficial effects that compared with that the traditional coil is manually wound by a copper stranded wire and a flat type copper wire, the fingerprint coil is processed by a water knife cutting machine, the winding precision is more accurate with less error, and thus the field uniformity difference of the fingerprint coil can be correspondingly reduced; meanwhile, under the restriction of the same radial space size, the copper plate cutting method can realize the maximum carrier cross section, thereby increasing the gradient field density, and reducing the strict requirement on the gradient coil cooling in the late period greatly.

A programmable illuminator for a photolithography system includes a light source, a first optical system having a light uniformizing element, a programmable micro-mirror device, and a second optical system that forms an illumination field that illuminates a reticle. The programmable micro-mirror device can be configured to perform shutter and edge-exposure-blocking functions that have previously required relatively large mechanical devices. Methods of improving illumination field uniformity using the programmable illuminator are also disclosed.

The invention discloses a bletilla seed direct-seeding two-stage seedling culture method. The method is characterized by including two different stages, namely bulblet forming and bulblet graded broadcast sowing, and graded culture is performed on seed seedlings for two times, so that the phenomenon that big, small and medium seedlings are mixed in conventional seed direct-seeding seedling culture is overcome effectively, and seed seedling orderliness and field uniformity after transplanting are improved. The method can be completed by a producer alone and can be undertaken by different producers, thereby being conducive to developing standard production of seed seedlings; no plant growth regulator is added in the culture process, so that aberration rate is lowered effectively; seed seedling production is high in yield and efficiency, more than 500 thousand plants can be produced per mu in each period, it only takes 9-10 months normally from seed broadcast sowing to field transplanting, and field orderliness is improved by 70%, and yield is increased by higher than 18%.

The invention provides a tissue displacement measurement method and a tissue displacement measurement system based on magnetic resonance acoustic radiation force imaging. The tissue displacement measurement method comprises the following steps: acquiring an image obtained by utilizing a two-dimensional spin-echo sequence and applying focused ultrasound; dividing an object tissue in the image into a region of interesting and a reference region; separating to obtain a tissue phase diagram of the reference region; carrying out polynomial model fitting on the tissue phase diagram of the reference region, so as to obtain multinomial coefficients; carrying out interpolation by utilizing the multinomial coefficients, and calculating to obtain a baseline phase diagram of the tissue in the region of interesting; acquiring a tissue phase diagram of the region of interesting from the acquired image; acquiring the phase difference of the tissue of the region of interesting; and acquiring the displacement of the tissue of the region of interesting by utilizing the phase difference of the tissue of the region of interesting. The method and the system are not insensitive to the tissue movement, the errors caused by the eddy and field uniformity can be reduced, the phase difference can be measured only through once of image collection, thus the displacement variation of the tissue can be obtained, and the displacement measurement speed of the tissue is accelerated.

Construction methods and techniques allow for a magnetic field of the field homogeneity required for the use in magnetic resonance imaging (MRI), in the order of 20 parts per million (ppm) in the area of interest (such techniques in the following will be indicated with the word “shimming”). The peculiarity of the constructive method is to obtain a homogeneous field region, usable for the MRI analysis, of linear dimensions equal to about 40% of the linear dimensions of the magnet. The shimming technique involves the use of conditioned magnetic material and allows accurate control of the magnetization of the corrective elements while using a material that inherently has a large spread in the magnetization value. The result is a low weight and small magnet suitable for MRI for dedicated clinical applications such as the analysis of the peripheral joint, the analysis of the ocular region, and veterinary applications.

The invention provides an automatically controlled microwave soil disinfecting device and a soil disinfecting method, relating to a device for preventing the soil from transmitting plant diseases andinsect pests. In order to solve the problems such as microwave leakage to endanger human body health, deficient microwave penetration depth, bad microwave field uniformity, and the like, in the existing microwave soil disinfecting method, the invention provides the automatically controlled and unpiloted microwave soil disinfecting device and the soil disinfecting method. The device comprises an automatic tracking finding and unpiloted trolley, a navigation belt of the trolley, a photoelectric sensor, a microwave generator, a microwave transmitting cover and a heat preservation layer. The method comprises the following steps of: disinfecting the soil before planting crops; piling the soil to be disinfected into ribs with bottom width of 25-60cm and distance of 10cm; slowly driving the trolley over the ribs; heating the temperature of the soil to be more than 70 DEG C with microwave; disinfecting harmful microorganism; and preventing the soil from transmitting the plant diseases and theinsect pests. The soil disinfecting method is high effective and environmentally friendly, and has no electro magnetic radiation, pollution and residue.

The present invention discloses a large-flow vertical radial flow adsorption device with the characteristic of layered parallel connection design, and a method thereof. The adsorption device comprises a housing, an adsorbent filling layer, an upper unit inner side multi-pore distribution cylinder, an upper unit outer side multi-pore distribution cylinder, an inner side diversion cylinder, a lower unit inner side multi-pore distribution cylinder, a lower unit outer side multi-pore distribution cylinder, an outer side diversion cylinder, a middle baffle, a middle baffle filler cover, a bottom support plate, and a flow finishing shelf. According to the present invention, the internal of the adsorption device is designed into the two separate adsorption unit connected in parallel and comprising the upper adsorption unit and the lower adsorption unit, such that the adverse influence of the height of the adsorption bed on the uniform flow field distribution can be eliminated, and the maximum design height of the vertical radial flow adsorption device can be significantly increased; and the large-flow vertical radial flow adsorption device with the characteristic of layered parallel connection design has advantages of shell housing diameter, small occupation area, high flow field uniformity and the like in the case of the same air treatment amount.

The invention discloses a vertical recycling, drying and calcining furnace for SCR (selective catalytic reduction) denitration catalysts. The vertical recycling, drying and calcining furnace comprises a furnace body, a material transport return system, a fire-resistant heat-insulation system, a drying zone, a calcining zone, a cooling zone, a first electric heating system, a second electric heating system, a first internal hot-air circulation unit, a second internal hot-air circulation unit, a third internal hot-air circulation unit, a moisture removing system, a waste gas exhaust system, a cooling and aerating air system, a waste heat recycling system and a control system. The material transport return system is matched with the furnace body, the fire-resistant heat-insulation system is arranged in the furnace body, the drying zone, the calcining zone and the cooling zone are sequentially arranged in the furnace body, the first electric heating system is arranged in the drying zone, the second electric heating system is arranged in the calcining zone, the first internal hot-air circulation unit is arranged in the drying zone, the second internal hot-air circulation unit is arranged in the calcining zone, the third internal hot-air circulation unit is arranged in the cooling zone, the moisture removing system is matched with the drying zone, the waste gas exhaust system is matched with the calcining zone, the cooling and aerating air system is matched with the cooling zone, the waste heat recycling system is connected between the cooling zone and the calcining zone, and the calcining furnace can work under the control of the control system. The vertical recycling, drying and calcining furnace has the advantages that calcining conditions such as heating rates, product calcining cycles, waste gas contents and product temperature field uniformity can be accurately controlled and guaranteed, and accordingly quality index requirements on products can be assuredly met.

The invention discloses a method and a system for quickly calibrating field uniformity of transient electromagnetic field. The method includes the steps of selecting apexes of a rectangular calibrating plane as measuring points; placing a rotary shaft (2) at the center of the calibrating plane, adjusting a positioning device (4) to limit a test bar (3) in the calibrating plane, and selecting length of the test bar (3) to enable a probe (6) to reach the apexes of the calibrating planes; rotating the test bar (3) in the calibrating plane to enable the probe (6) to locate at the apexes of the calibrating plane respectively, and using the probe (6) to measure values of field intensity of the apexes of the calibrating plane. The method and the system require no frequent movement of a support for supporting and fixing the probe, and after the support is fixed, repeated adjustment of the specific position and angle of the probe on the support is not needed. The method and the system are simple in calibrating process, fast in calibration and short in calibrating time.

A microwave reactor for processing a flow of a mixture, said reactor comprising a reaction chamber having an unpressurized interior and a reaction block disposed within the interior of the reaction chamber, with at least one antenna disposed within the interior of the chamber; and at least one generator of electromagnetic radiation connected to the antenna so that the flow may circulate through said reaction block, and the generator generates a radiation that is uniformly and homogeneously propagated in the chamber and is evenly absorbed by the mixture. The present invention provides embodiments of microwave reactors capable of processing reaction volumes normally found in early stage drug development and pre-clinical studies, as well as embodiments sufficient for commercial production, the designs disclosed incorporate process controls as well as high microwave field uniformity. The reactor may process batches, or may be a flow through design, or a ‘stop flow’ design whereby flow is admitted, a batch is processed and the flow is re-started.