106 results about "Primary field" patented technology

A method of imaging an object, such as a diseased human heart or bone, in a nontransparent medium, such as the human body, involves placing an array of transmitters and receivers in operational association with the medium. The transmitters generate a harmonic (frequency domain) or pulse (time domain) primary electromagnetic field (EM) which propagates through the medium. The primary field interacts with the object to produce a scattered field, which is recorded by the receivers. The scattered EM field components measured by the receivers are applied as an artificial EM field to generate a backscattering EM field. Cross power spectra of the primary and backscattering fields (in the frequency domain) or cross correlation between these fields (in the time domain) produce a numerical reconstruction of an EM hologram. The desired properties of the medium, such as conductivity or dielectric permittivity, are then derived from this hologram.

The invention relates to an emission current subdivision control circuit based on a magnetic source electromagnetic method. The emission current subdivision control circuit based on a magnetic source electromagnetic method adopts a four-division accurate control mode, and is formed in a way that a primary power supply is connected with loading coils and is connected in parallel with a reverse overshooting control circuit through an H bridge inversion main circuit for outputting flat-top current, and after passing through an auxiliary power supply, the positive end of the primary power supply is respectively connected in parallel with a rising edge control circuit and a falling edge control circuit on the H bridge inversion main circuit. Compared with the prior art, the invention adopts the output current subdivision control, solves the conflict of mutual restriction between the flat-top section control and the rising edge and falling edge control mode, reduces the ripples and the electromagnetic interference of the flat-top current, decreases the turn-off time of the output current, and reduces the effect of the primary field in the shallow detection result interpretation of a large-magnetic moment transient electromagnetic device. Simultaneously, the invention reduces the switching number of the power device, reduces the switching loss of the power device, simplifies the control circuit, saves the cost and improves the efficiency.

The present invention relates to potential difference signal acquiring method and system for distributive parallel intelligent electrodes. In certain area, several groups of intelligent electrodes comprising several work electrodes each are distributed, and each work electrode is connected to signal regulating and measuring circuit. Each intelligent electrode has its every work electrode set in one of four work states, positive supplying electrode, negative supplying electrode, common earth and sampling. Of all the work electrodes in several intelligent electrodes, only three are in positive supplying electrode, negative supplying electrode and common earth state separately while the others being in potential difference signal sampling state. During the powering process, the natural field, primary field and secondary field of all the electrodes are measured and the potential difference signals are A/D converted and fed to computer for saving and processing circularly.

An improved magnetic torque transducer involves a method and apparatus for compensating effects of uniform and/or non-uniform magnetic sources by placing three sets of magnetic field sensors around a shaft with at least one magnetized zone. The set of primary magnetic field sensor or sensors is placed proximate to the magnetized zone, both the second and third sets of secondary magnetic field sensors being placed by pre-determined distances to the primary set of magnetic field sensor or sensors, so that primary field sensors always in a position with higher magnetic field strength arise from applied torque than that of secondary sensors. And a method is developed to use the second and third signals from secondary sensors to adjust the primary signal to compensating for the effects of the uniform and/or non-uniform ambient magnetic field sources.

A system provides guidance to a vehicle on an approach to a position. A guidance transmitter stationed at the position includes light sources arranged in an array and a controller coupled to the light sources. The array defines a primary field-of-view (FOV) from which all light sources are visible. The light sources are divided into a plurality of sections with each section having a portion of the light sources associated therewith. Operation of each section of light sources is governed by the controller in accordance with unique cyclical on/off sequences. A primary waveform of light energy is defined by a composite of the cyclical on/off sequences visible from within the primary FOV. A plurality of secondary waveforms of light energy are defined by the cyclical on/off sequences visible from positions outside of the primary FOV. A guidance receiver mounted on a vehicle traveling towards the position of the guidance transmitter includes (i) sensor(s) for sensing light energy generated by those light sources visible thereto, (ii) a database for storing calibration waveforms indicative of corresponding guidance correction signals, and (iii) a processor for determining which one of the calibration waveforms matches or is closest to the sensed one of the primary waveform and secondary waveforms. The guidance correction signal associated with the matching calibration waveform can be used to control navigation of the vehicle.

The invention relates to an electromagnetic prospecting sending-receiving integration method and a device. The invention is suitable for the fields of geophysical prospecting, engineering geological prospecting, underground military target detection, nondestructive inspection and the like. The technical scheme of the invention is as follows: arranging an inner receiving coil 1 in a sending coil 3; arranging an outer receiving coil 2 outside the sending coil 3; ensuring that magnetic flux passing through the inner receiving coil 1 and the outer receiving coil 2 is equivalent and is in opposite sign under the action of primary field; mutually offsetting primary field induced voltage; and only outputting a secondary field signal. The device comprises a transmitter 4, a sending coil 3, an inner receiving coil 1, an outer receiving coil 2, a signal conditioning circuit 5 and a receiver 6, wherein the inner receiving coil 1 is connected with the outer receiving coil 2, and the coil 1 and the coil 2 are connected with the signal conditioning circuit 5. The invention has the advantages of eliminating primary field influence, reducing signal dynamic range, expanding the practicability of small-wireframe same-point device and realizing integration of the sending coil and the receiving coil.

The present invention relates to the field of x-ray imaging. More particularly, embodiments of the invention relate to methods, systems, and apparatus for imaging, which can be used in a wide range of applications, including medical imaging, security screening, and industrial non-destructive testing to name a few. Specifically provided as embodiments of the invention are systems for x-ray imaging comprising: a) a first collimator-and-detector assembly having a first operable configuration to provide at least one first dataset comprising primary x-ray signals as a majority component of its data capable of being presented as a first image of an object subjected to x-ray imaging; b) a second collimator-and-detector assembly having a second operable configuration or wherein the first collimator-and-detector assembly is adjustable to a second configuration to provide at least one second dataset comprising primary and dark-field x-ray signals as a majority component of its data capable of being presented as a second image of the object; and c) a computer operably coupled with the collimator-and-detector assemblies comprising a computer readable medium embedded with processing means for combining the first dataset and the second dataset to extract the dark-field x-ray signals and produce a target image having higher contrast quality than the images based on the first or second dataset alone. Such systems can be configured to comprise at least two collimator-and-detector assemblies or configurations differing with respect to collimator height, collimator aperture, imaging geometry, or distance between an object subjected to the imaging and the collimator-and-detector assembly.

The invention relates to a device for positioning and detecting an accident well on the basis of a transient electromagnetic method. The device comprises a relief well and the accident well, an emitting electrode and a micro inertial measurement unit combination are arranged on a drill collar in the relief well at an interval, the micro inertial measurement unit combination comprises a three-axis flux-gate sensor, a gravity accelerometer and an underground receiving unit, the emitting electrode is connected with a high-power pulse generation circuit through a cable, the micro inertial measurement unit combination is sequentially connected with a ground receiving unit and a high-power power supply through cables, the high-power power supply can provide power for the high-power pulse generation circuit and the ground receiving unit, the emitting electrode receives current signals and generates a primary field, the primary field motivates an accident well sleeve to generate a secondary field, and signals received by the three-axis flux-gate sensor and the gravity accelerometer are transmitted to and processed in the underground receiving unit and are uploaded to the ground receiving unit. The device can be widely used in the processes of rescuing and detecting in the accident well, grade assessing of an accident and formulating of rescue schemes.

An implantable pump includes a base plate and a can that are parts of the pump housing. The base plate bottom divides the housing into a first electronics chamber and a second chamber. A bellows mechanism is connected to the base plate and is disposed within the second chamber. The bellow mechanism has an expandable sidewall and a bottom plate. The bellow mechanism divides the second chamber into a medicament receiving portion and a non-medicament-receiving portion. The bellow mechanism has an intermediate plate disposed within the medicament-receiving portion. A coil is disposed in a recess on the lower surface of the base plate, and the coil is spaced from an internal wall of the recess. The amount of fluid remaining in the implantable pump can be monitored by energizing the coil. A primary magnetic field is generated by the energized coil. A secondary magnetic field, which is dependant on the position of the bottom and intermediate plate of the bellow mechanism, couples back to the primary field affecting the electrical characteristics of the coil. The amount of fluid remaining in the reservoir is determined based on the resulting changes in the electrical characteristics of the coil.

The invention relates to a transient electromagnetic quick three-dimensional human-machine interaction inversion method. The transient electromagnetic quick three-dimensional human-machine interaction inversion method includes that gathering geological information, physical geography information and physical logging information; using the information to analyze comprehensively to build a geo-electric model of a surrounding rock; using the model to forwardly calculate the TEM response of the surrounding rock, and calculating a pure anomaly field (three-component) according to the actual TEM response; using an electric current loop to be equivalent to the vortex of a target geological body generated by the excitation of a primary field at a time, enabling the field generated by the equivalent current loop to gradually get close to the three-component field value observed at the earth surface, and inverting to obtain the position, size, inclination angle, inclination direction and the other geometrical parameters of the current loop so as to obtain the information of the target geological body; judging whether the information is reasonable according to the known information, if so, obtaining the information of the target geological body to realize three-dimensional TEM human-machine interaction inversion, otherwise, comprehensively analyzing again to construct the geo-electric model of the surrounding rock, entering the next circulation, and stopping till the information is reasonable.

The invention discloses a transient electromagnetic instrument. The transient electromagnetic instrument comprises a transmitter, a transmitting coil, a compensation coil, a receiving coil and a receiver, wherein the transmitting coil, the compensation coil and the receiving coil are coaxial and parallel to one another, and the diameter of the transmitting coil and the diameter of the receiving coil are the same; the compensation coil and the receiving coil are connected in series and opposite in winding direction, and the receiving coil is located over the compensation coil and the transmitting coil, so that the magnetic flux of a primary field generated by the transmitting coil penetrating through a compensation coil and receiving coil combination is equal to 0 or close to 0 all the time. The invention also discloses a compensation algorithm of the transient electromagnetic instrument. The influence of the primary field can be eliminated under the condition that a secondary field isnot weakened, early-stage signals of the secondary field are received, the signal dynamic range of the secondary field is enlarged, and the receiving accuracy is improved.

The invention discloses a helicopter magnetic resonance and transient electromagnetic combined detection device and method. The helicopter magnetic resonance and transient electromagnetic combined detection method comprises the steps that the upper portion of a detected area carries a transmitting coil and a receiving coil through a helicopter; a variable-frequency converting current with the local Larmor frequency as the reference is introduced into the transmitting coil, thus heat-insulation pulses are formed, and a hydrogen nucleus in groundwater is stimulated to generate the magnetic resonance phenomenon; after stimulation is stopped, the hydrogen nucleus self-rotates to generate the relaxation phenomenon, and the receiving coil inducts a magnetic resonance signal generated by macroscopic magnetic moment precession; a main control unit controls a receiving machine to receives the magnetic resonance signal, and the magnetic resonance signal is transmitted to an upper computer to bestored; after magnetic resonance detection is completed, a periodic pulse sequence is introduced into the transmitting coil, and the sequence is quickly turned off to form a primary field; and the primary field is spread in dielectric media with different electrical properties and reflected to generate a secondary field, and the receiving coil inducts a transient electromagnetic signal formed by the secondary field. According to the helicopter magnetic resonance and transient electromagnetic combined detection device and method, the problems that traditional magnetic resonance and transient electromagnetic combined detection is low in efficiency and is limited in application occasion are solved.

The invention relates to a primary field self-counteracting device for a time-domain airborne electromagnetic method. A data acquisition system is mounted on an airplane; a cross-shaped support for supporting an emission coil, a z-component receiving coil, an x-component receiving coil, a y-component receiving coil and a calibration coil is hung on the bottom of an airplane cabin through a sling;and the z-component receiving coil, the x-component receiving coil and the y-component receiving coil are connected with a pre-amplifier through leads, and then connected with a data recording systemthrough signal lines. Compared with the existing similar equipment, the primary field self-counteracting device can effectively suppress the influence of the primary field on the receiving coils, thereby greatly widening the dynamic range of the secondary field signals received by the receiving coil and improving the exploration accuracy and efficiency. In addition, the receiving coils are of a double-damping structure, which can effectively protect the receiving coils so as to obviate the influences of the vibration on the received signals and improve the receiving quality of the late secondary field signals. The calibration coil has a 45-degree angle with the three receiving coils respectively to provide convenience for personnel in checking the system performance, thereby improving thesystem checking efficiency.

A wave-based tomographic imaging method and apparatus based upon one or more rotating radially outward oriented transmitting and receiving elements have been developed for non-destructive evaluation. At successive angular locations at a fixed radius, a predetermined transmitting element can launch a primary field and one or more predetermined receiving elements can collect the backscattered field in a "pitch/catch" operation. A Hilbert space inverse wave (HSIW) algorithm can construct images of the received scattered energy waves using operating modes chosen for a particular application. Applications include, improved intravascular imaging, bore hole tomography, and non-destructive evaluation (NDE) of parts having existing access holes.

The invention relates to a method for determining the geological information of an underground target body by a transient electromagnetic field B. The method comprises the steps of: by using an earth lead, transmitting a primary field into the ground for the underground target to be detected; after the primary field is closed, by applying an induction coil, measuring the induced electromotive force V which is generated in a horizontal coil by the change of a secondary magnetic field along the vertical direction; converting the induced electromotive force V into a magnetic field differential parameter dB/dt; converting the parameter dB/dt into a parameter of the field B by integration; determining the apparent resistivity of the target body according to the parameter of the field B; determining the geological information of the underground target according to the apparent resistivity of the target body. During data interpretation, whole-process apparent resistivity extraction is carried out on the data of the field B by dichotomy, so that the accurate exploration for the geological target body is completed. Compared with the conventional method for calculating the apparent resistivity by the induced electromotive force V, the method provided by the invention is capable of eliminating the multiplicity of solution of the apparent resistivity, and is more beneficial to the exploration of a deep good-conduction target body; furthermore, after the method is used, the detailed geological information of the geological target body can be obtained.

A delta-relaxation magnetic resonance imaging (DREMR) system is provided. The system includes a main field magnet and field shifting coils. A main magnetic field with a strength B0 can be generated using the main filed magnet and the strength B0 of the main magnetic field can be varied through the use of the field-shifting coils. The DREMR system can be used to perform signal acquisition based on a pulse sequence for acquiring at least one of T2*-weighted signals imaging; MR spectroscopy signals; saturation imaging signals and MR signals for fingerprinting. The MR signal acquisition can be augmented by varying the strength B0 of the main magnetic field for at least a portion of the pulse sequence used to acquire the MR signal.

The invention discloses an electromagnetic-method-prospected primary-field loose-coupling reception device and a method, comprising: a transmitter, a transmission coil, a signal regulating module and a receiver. The two transmission output ends of the transmitter are connected with the two ends of the transmission coil. The device of the invention further comprises n reception coils that form a reception coil module in connection with the signal regulating module. The output end group of the signal regulating module is connected with the receiver. The reception coil module is arranged at the edge part of the transmission coil in such a manner that the two partially intersect, and some orthographic projection of the transmission coil overlaps some orthographic projection of the reception coils. According to the invention, the overlapping phenomenon of the primary field and the secondary field of reception coils is eliminated; the dynamic scope of the reception signal is reduced; the difficult problem with receiving weak secondary field signal is solved. In addition, the device and the method can be applied widely. As an integrated system, the device can be used and operated conveniently and the regulation effect is both precise and reliable.

There is described an MRI system in which the detection of the NMR signal is performed by a resonant input at a median field range above 100 gauss and where the main field is cycled to a low field of below 50% of the resonant frequency after the excitation of the NMR signal for a period sufficient to develop differences in magnetisation (T1). The advantage of this system is that images can be generated at much lower field intensities than prior art systems and is able to detect abnormalities in tissue such as cancerous tissues in a patient.

The invention relates to a transient electromagnetic method (TEM) technology and discloses a detection device based on the TEM. The device comprises a transmitting antenna for generating a transient electromagnetic field and a receiving antenna for receiving a secondary electromagnetic field excited by the transient electromagnetic field, wherein the transmitting antenna consists of a coil array which is composed of at least two coils; and an electromagnetic field generated by the coil array is converged towards a set area. According to the detection device based on the TEM, a single coil of a primary field transmitting antenna of the TEM is modified into the coil array consisting of a plurality of coils, and related parameters of various coils in the array are adjusted, so that the generated electromagnetic field vectors are superposed and converged to the set area, and the divergence of the electromagnetic field generated by the transmitting antenna is greatly improved; and therefore, the coverage range of the primary field is constrained, and the converging performance of the transmitting antenna is improved. The detection device is mainly used for the field of electromagnetic detection, such as prospection, underground pipeline detection, metal detection and the like.

A method of security screening and inspection of people in airlines, ships, or secured buildings, involves placing an array of transmitters and receivers in operational association with the medium. The transmitters generate a broad band harmonic (frequency domain) or pulse (time domain) primary electromagnetic field (EM) field, including the lower frequency portions of the EM spectrum, whose propagation is typically characterized by the diffusion phenomena, or by the combination of the diffusion and wave phenomena. The primary field propagates through and interacts with the examined person and any objects carried by the person to produce a scattered field, which is recorded by the receivers. The scattered EM field components measured by the receivers are applied as an artificial EM field to generate a backscattering EM field. Cross power spectra of the primary and backscattering fields (in the frequency domain) or cross correlation between these fields (in the time domain) produce a numerical reconstruction of an EM hologram. The desired properties of the person, including the properties of any objects carried by the person, such as conductivity or dielectric permittivity, are then derived from this hologram.