摘要:
A method for modeling a reservoir response in a subsurface system is provided. The subsurface system has at least one subsurface feature. Preferably, the subsurface system comprises a hydrocarbon reservoir. The method includes defining physical boundaries for the subsurface system, and locating the at least one subsurface feature within the physical boundaries. The method also includes creating a finite element mesh within the physical boundaries. The finite element mesh may have elements that cross the at least one subsurface feature such that the subsurface feature intersects elements in the mesh. A computer-based numerical simulation is then performed wherein the effects of the subsurface feature are recognized in the response. The reservoir response may be, for example, pore pressure or displacement at a given location within the physical boundaries.
摘要:
A optical Biopsy method and an apparatus are used in the diagnosis of precancerous lesion for locating the place and determining the level of malignant tumor. The apparatus comprises light source (1, 10) a light channel system, an endoscope (21) and a circuit system. The light sources include an excited light (1) and a cold light source (10). The cold light source and the excited light in the light channel system go through the end of the light guide of the endoscope via optical fiber bundle and irradiate the tested living tissue (22). The white light image signal and the intrinsic fluorescence image signal reflected from the tested living tissue (22) are received by a weak fluorescence CCD (6) that tightly connects to the end of the endoscope (21) and then transmit to the circuit system via a signal wire (9) to produce the image in the display (17). The weak fluorescence signal reflected from the tested living tissue (22) is transmitted to the circuit system via the weak fluorescence fiber bundle (4) protruding from the forceps hole of the endoscope to produce the spectrum image (16).
摘要:
An AC-DC converter includes a DC reference voltage generation unit that creates a DC reference voltage waveform based in part on a feedback signal. The AC-DC converter also includes an SCR firing unit that receives a variable frequency power output from the generator and that provides firing signals. The AC-DC converter further includes SCRs arranged as a positive bank of SCRs and a negative bank of SCRs. The AC-DC converter further includes a modulator unit that receives the firing signals and the DC reference voltage waveform, and that respectively outputs SCR gate signals to the SCRs. The AC-DC converter also includes a filter unit provided between the positive and negative banks of SCRs. The AC-DC converter also includes a voltage feedback path for feeding back the DC output voltage as the feedback voltage waveform.
摘要:
A permanent magnet brushless DC motor controller, and method of operation of the controller, provide effective and smooth regulation of the speed of the motor from zero to above base speed (e.g. at least about 100% above base speed). For a three phase motor the controller comprises three Hall sensors, a power amplifier comprising a plurality of power electronic switch connected to the motor, two switches (bottom and top) for each phase, and at least an eight bit microprocessor connected to and controlling the switches, and a frequency to voltage controller. The Hall sensors are connected substantially directly to the microprocessor, and also through the frequency to voltage converter. In response to sensing by the Hall sensors, both directly and through the frequency to voltage converter, the microprocessor is used to control the electronic switches to smoothly speed regulate the motor both below and above base speed. Below base speed the microprocessor utilizes a commutation truth table, and the bottom switches provide pulse width modulation, whereas equal to and above base speed the microprocessor uses first and second jump tables, the first jump table comprising the commutation truth table forward rotated one step, and the second jump table the commutation truth table forward rotated two steps.
摘要:
A brushless transversal-flux permanent magnet motor has a stator construction that forms a virtual bobbin, so that windings may be simply circumferentially wrapped around the stator, eliminating the need for winding insertion. The stator may be constructed of first and second core structures each having an elongated powdered iron pole piece central portion with end terminations, and integral with a tubular element also of powdered iron. Epoxy, or like non-magnetic material, fills in the volume between the pole piece end terminations to form a disc-shaped structure, the windings wrapping around the tubular elements. A discontinuity is provided on each pole piece and termination to allow start-up. The rotor may be a yoke having permanent magnet rings aligned with the pole pieces, and mounted for rotation by a shaft central of the tubular elements engaging bearings in the tubular elements. A circuit board containing motor control circuitry (for switching connection of the windings to a source of electrical power) can be connected to the stator to mechanically mount it while facilitating connection of the windings to the circuitry.
摘要:
Electronic solid state circuitry is provided which takes the place of Hall-effect sensors in brushless DC motors, providing output signals substantially the same as those of Hall-effect sensors. The Hall-effect sensors in existing motors may be deactivated or removed and functionally replaced by the solid state circuit. The circuit may include a number of D flip flops and a NAND gate connected to a voltage controlled oscillator by a switch which is part of a start up circuit. A direction reverse circuit, a sampling logic circuit (to determine which phase is non-energized at a particular point in time), and a commutation error detector circuit are also preferably provided. New motors utilizing the circuitry have increased reliability and precise velocity regulation.
摘要:
A stator core for rotary high power density electro-mechanical transducers formed of multiple segments which have a plurality of radially oriented teeth. The stator core is a composite of two or more segments circumferentially combined to form a cylindrical stator or armature for electric motors or generators. The segments are wound with wire either when the segments are aligned linearly, when arranged circumferentially on the inside surface of a jig or about a cylinder. The wound stator can have teeth extending radially outwardly or inwardly, to accommodate an outside or inside rotor.