463results about How to "Improve the induction effect" patented technology

A chip-type sensor against ESD and stress damages and contamination interference includes a substrate structure and a protection layer covering over the substrate structure. The protection layer includes, from bottom to top, a first layer for providing a first stress against the substrate structure, a second layer for providing a second stress against the substrate structure, and a third layer for providing a third stress against the substrate structure. The first stress and the third stress belong to one of a tensile stress and a compressive stress, and the second stress belongs to the other of the tensile stress and the compressive stress.

The embodiment of the invention provides a voice recognition method based on a mobile terminal. The method comprises the following steps: collecting environmental sound signals; indentifying the environmental sound signals according to preset identification information; when the environmental sound signals contain special sound signals matching the preset identification information, judging whether the loudness of the special sound signals reach the preset threshold; and if so, controlling to output the special sound signals. Correspondingly, the embodiment of the invention also provides a mobile terminal. The mobile terminal of the invention utilizes the voice recognition technology, overcomes the application defects of the headset of the existing mobile terminal, eliminates the hidden danger caused by the reduced induction to the external environment sound when the user uses the headset of a mobile terminal and promotes the user experience.

The invention relates to an urban intersection traffic signal control method, relates to a multi-phase-jump and vehicle full-dynamic induction traffic control method, and aims to flexibly control traffic signals at intersections by using a traffic signal instrument so as to improve the traffic pass property of vehicles at the intersections and reduce the total delay time of vehicles. The method comprises the following steps: 1) setting an upstream vehicle detector and a parking line vehicle detector at each lane of a traffic intersection, and detecting dissipating vehicle and information of vehicles entering the intersection in real time; 2) according to the numbers of vehicles waiting in different lanes and vehicles running into the intersections, automatically transmitting passing signals to busy lanes by using a busy lane priority pass method through a traffic signal instrument control system so as to induce the vehicles in the lanes to pass prior; 3) by using a method that compatible lanes adopt one same phase and non-compatible lanes are subjected to phase-jump induction control, providing the priority pass right for lanes with a plenty of waiting vehicles or a lane into which a plenty of vehicles run. Due to the adoption of the method, a relatively good induction effect can be achieved at intersections with unsaturated traffic vehicles.

A stray-light-coupled biometrics sensing module includes a light-transparent body, a display unit and an optical module. The light-transparent body has a front side and a backside. The front side is configured to support an organic object thereon. The display unit attached to the backside of the light-transparent body displays a frame. The optical module is attached to the backside of the light-transparent body through an adhesive, and is disposed adjacent to the display unit. First light rays of the frame emitted from an eye-viewing screen couple into the organic object through the light-transparent body. After travelling a short distance in the organic object, the first light rays couple out of the organic object and re-enter the light-transparent body as second light rays entering the optical module. The optical module senses the second light rays to generate a biometrics image signal. An electronic apparatus is also disclosed.

A fan includes a motor and an impeller. The motor drives the impeller to rotate and includes a base, a bearing, a stator, a rotor and a magnetic element. The central portion of the base is extended to form a bushing for accommodating the bearing therein. The stator telescopes around the bushing. The rotor is disposed corresponding to the stator and has a shaft passing through the bearing. The magnetic element is disposed at the bottom of the bushing and located adjacent to one end of the shaft.

The invention relates to a system and a method for monitoring the sand production rate of an oil-gas well. The system comprises a high-frequency signal sensing device and a control device, wherein the high-frequency signal sensing device comprises an oil stream introducing pipeline and an oil stream returning pipeline which are arranged in parallel on an oil-gas production pipeline of the oil-gaswell; the oil stream introducing pipeline is provided with a fixed displacement pump; the oil stream returning pipeline is provided with a pressure sensor; an oil stream monitoring pipeline is arranged between the oil stream introducing pipeline and the oil stream returning pipeline; a signal sensing drum is arranged between the oil stream monitoring pipeline and the oil stream returning pipelineand bonded with a high-frequency signal sensor; the control device comprises a data acquisition system which acquires pressure and impact signals monitored by the pressure sensor and the high-frequency signal sensor, transmits the acquired signals to a filter amplifier for filtering and signal amplifying and transmits the filtered and amplified signals to a signal processing unit; and the signal processing unit analyzes and judges the impact signals monitored by the high-frequency signal sensor so as to monitor the sand production rate of oil-gas stream in real time. The system and the methodare suitable for the field of oil-gas well development engineering.

The invention discloses a fingerprint identification module group and a preparation method therefor as well as electronic equipment provided with the fingerprint identification module group. The fingerprint identification module comprises a laminated structure, a supporting piece, a fingerprint identification chip, a flexible circuit board and a reinforcement plate, wherein the supporting piece covers the laminated structure, and the laminated structure comprises a cove plate; the fingerprint identification chip is arranged under the cover plate; the flexible circuit board is arranged under the fingerprint identification chip, and is electrically connected with the fingerprint identification chip; and the reinforcement plate is arranged under the flexible circuit board. A fitting surface of the fingerprint identification module group is very flat, and has a good smooth and flat touch feel; and induction effect of the fingerprint identification chip is better.

The invention discloses a phellinus igniarius mycelium liquid fermentation method by utilizing a fungal elicitor for improving the yield of flavone of phellinus igniarius, which comprises the steps of: inoculating a fungal elicitor strain for activated culture, and then inoculating and culturing a fungal block to obtain a fungal elicitor mycelium through filtration; then drying, grinding and crushing the fungal elicitor mycelium, adding the crushed fungal elicitor mycelium into ethanol for soaking, filtering the obtained solution, collecting filter residue, orderly adding a mixed solution of chloroform and normal butanol, acetone and water into the filter residue for washing, adding trifluoroacetic acid into a dry substance after the air-drying, performing boiling water bath for 0.5 to 2 hours, then filtering the obtained solution, taking a filtrate for neutralization, standing the filtrate, using a microporous filtering film with the pore diameter between 0.4 and 5mu m to filter the filtrate for sterilization to obtain the fungal elicitor, and cryopreserving the fungal elicitor at the temperature of between 10 and 20 DEG C below zero; inoculating a phellinus igniarius strain for activated culture, and then inoculating a fungal block for fermentation culture; and adding the fungal elicitor into the phellinus igniarius to continue culturing to obtain a phellinus igniarius mycelium within 1 to 5 days of liquid fermentation culture of the phellinus igniarius. The method has simple process, low cost and remarkable effect, can greatly improve the content of the flavone of phellinus igniarius cells, and is a production method with industrialization prospect.

The invention relates to a novel biological scaffold material for bone repair and a preparation method thereof. PLGA and PLA with a mass ratio of 1: 1-10: 1 are dissolved into chloroform, dimethyl sulfoxide, 1, 4-dioxane or a mixed liquid of the 1, 4-dioxane and ultrapure water, and then pearl powder which is subjected to partial or complete deproteinization treatment is added into the obtained product according to the proportion of the PLGA / a PLA mixture to the pearl powder (mass ratio) is 1: 1-10: 1 to obtain forming slurry. A three-dimensional scaffold with high porosity and connectivity rate is designed through a 3D software, and then a low-temperature rapid forming system is utilized to ensure that the three-dimensional scaffold is formed to obtain a scaffold with a microporous structure. An artificial bone biological scaffold material prepared by the method has a three-dimensional scaffold structure that a macroscopic structure has aperture channels with diameters of between 100 and 500mu m and a microstructure has micropores with diameters of between 10 and 20mu m, wherein micron pearl powder is dispersedly distributed on walls of the micropores. The porosity is between 60 and 90 percent, and a macroporous structure is perforated in three directions of X axis, Y axis and Z axis, and has 100 percent of connectivity.

The invention provides a multi-light position multi-dimensional tunnel lighting mode which is composed of a plurality of dimensional lighting components, which are respectively the low-light position reverse lighting component, the homodromous lighting component, the transverse lighting component and the high-light position reverse lighting component. All the lighting components are independent on lighting functions, light color scope, lighting direction and lighting space, and can be individually adjusted. Each component is provided with a special light source and a light which are installed at low position and independently run based on the task characteristics, and the special demands on pavement lighting, space lighting and tunnel lighting can be met. The efficiency can be maximized in each task, so that the total lighting can be comprehensively optimized. With the adoption of the multi-light position multi-dimensional tunnel lighting mode, the shortcomings of the traditional tunnel lighting mode can be overcome; the light source and the light which have different functions perform relevant functions, so that a series of problems of tunnel lighting can be effectively solved, and the lighting efficiency can be greatly improved. The multi-light position multi-dimensional tunnel lighting mode is independently applied and developed based on the property of the low power and high light efficiency light source; the lighting mode of traditional tunnel light is completely removed; and the mode of simply replacing HPS (High Pressure Sodium) and MH (Metal Halide) lights with the LED lights can be changed.

The invention belongs to the technical field of biosensors, and in particular discloses an electrochemical sensor based on a metal organic framework-vertical graphene composite structure and a preparation method thereof. The preparation method specifically comprises the following steps: (1) growing vertical graphene on a stainless steel substrate; (2) synthesizing various different metal organic framework (MOF for short) materials such as ZIF-8, KAUST-1 and Ni-MIL-77 by taking the vertical graphene on the stainless steel substrate as a template; and (4) constructing the electrochemical sensorby taking the MOF-vertical graphene composite nanostructure as an electrode material. The electrochemical sensor has higher electric conductivity, larger specific surface area and more types of responsive substance surfaces, and the preparation method is relatively clear, different MOFs can be made by selecting materials according to performance of chemical reactions directly, and the spatial structure of the MOF material can be altered according to performance demand, so that the electrochemical sensor which further meets the demand can be manufactured more easily, and is wide in applicationrange.

The invention discloses an ionic induction type artificial skin array structure and a preparation method thereof. The array structure is characterized in that the array structure is an array structure formed by distributing composite electrode fibers in a crossed mode, or an array structure formed by distributing composite electrode fibers and flexible fiber electrodes made of conductive materials in a crossed mode, or a fabric structure formed by weaving composite electrode fibers, or a fabric structure formed by blending and weaving composite electrode fibers and flexible fiber electrodes made of conductive materials, wherein the composite electrode fibers are composed of core layers and sheaths, the core layers are flexible fiber electrodes made of the conductive materials, the sheaths are wrapping layers of the flexible fiber electrodes made of polyelectrolyte, the outer surfaces of the core layers are wrapped by the sheaths, and the two ends of the core layers are exposed. The ionic induction type artificial skin array is based on ionic migration, and can simulate the biological skin tactile sense biological electric induction principle. Compared with artificial skin materials of other types, the induction ability higher, and response is more sensitive.

The invention relates to a rapid propagation method for culturing Rieger begonias tissue, which comprises the following steps that: explant material is treated, that is, the explant material is selected for treatment to prepare the explant meeting the requirement; then inducement is carried out, that is, the explant prepared in the first step gets vaccinated to culture medium to induce bud on inducing conditions; the inducing condition that the light intensity with illuminance is less than 1500lx is met. As the lighting condition during the fast propagation of Rieger begonias tissue is further optimized, the application of the rapid propagation method for culturing Rieger begonias tissue causes the inducement time to be shorter and ensures the inducement rate to be higher and reach 100 percent.

The invention discloses a method for inducing and producing dalbergia substances on a dalbergia odorifera tree. An artificial wound is formed in the xylem of the dalbergia odorifera tree, an inducer is applied around the wound, the wound is wrapped and treated by using a preservative film or a plastic film for 6 to 12 months, purple brown oily substances and purple brown discolored xylem formed around the wound are cut off and collected, and the dalbergia substances are obtained after drying and crushing such purple brown oily substances and purple brown discolored xylem. The invention has simple technique and convenient operation and greatly shortens the production cycle of the dalbergia substances by using the artificial induction manner, with outstanding induction effect, thus being applicable to mass production of standardized commodities, effectively relieving contradiction between supply and demand of dalbergia, providing effective approaches for protecting, developing and utilizing dalbergia odorifera tree resources and having significant economic, social and ecological effect.

The invention discloses a method for cultivating, rapidly propagating and regenerating tissues of seedlings of radix aconiti lateralis preparata. Stem fragments with auxiliary buds, stem fragments, sterile leaves and seeds of the radix aconiti lateralis preparata are used as explants, rapid propagation systems and seed sterile cultivation and regeneration systems for optimizing the radix aconiti lateralis preparata are built by the aid of links of disinfection conditions, bud induction, bud multiplication, rooting and transplanting, callus induction, multiplication and differentiation and the like, and technical support can be provided for industrializing seedling growing. The method includes a process for rapidly propagating the radix aconiti lateralis preparata, a process for regenerating and propagating the radix aconiti lateralis preparata and a process for rapidly growing the seedlings of the radix aconiti lateralis preparata. The process for rapidly propagating the radix aconiti lateralis preparata includes a technology for rapidly propagating the stem fragments of the radix aconiti lateralis preparata and a technology for rapidly propagating the seeds; the process for regenerating and propagating the radix aconiti lateralis preparata includes a technology for regenerating and propagating the stem fragments and adventitious roots of the radix aconiti lateralis preparata and a technology for regenerating and propagating the sterile leaves of the radix aconiti lateralis preparata. The stem fragments and the adventitious roots of the radix aconiti lateralis preparata are used as explants in the technology for regenerating and propagating the stem fragments and adventitious roots of the radix aconiti lateralis preparata. The sterile leaves of the radix aconiti lateralis preparata are used as explants in the technology for regenerating and propagating the sterile leaves of the radix aconiti lateralis preparata. The method has the advantages that the radix aconiti lateralis preparata seedling rapid propagation and growing efficiency can be obviously improved, the seedling growing periods can be obviously shortened, technical support can be provided for production application of radix aconiti lateralis preparata seedling rapid propagation and growing, and problems in the aspect of seedling propagation and growing on current markets can be effectively solved.

The invention discloses a compound inducer for improving the capacity of a microorganism strain for producing a laccase, which comprises bagasse, ethanol and a bluestone liquid; and a comparison research carried out on a whiterot fungi strain XG8 by utilizing the compound inducer shows the laccase capacity in a fermentation liquid is improved by 10 times than that of the strain not added with thecompound inducer. The inducer of the invention is quite suitable for being applied to the large-scale production of industrialized laccases.

The invention discloses a rotor position detection device for a permanent magnet motor. The rotor position detection device comprises a Hall position sensor, a permanent magnet, a rotor core and a stator core, wherein the permanent magnet, the rotor core and the stator core form the permanent magnet motor; the permanent magnet is positioned between the rotor core and the stator core, and is connected with the rotor core; the Hall position sensor is arranged above the upper surface of the permanent magnet; a certain space is reserved between the Hall position sensor and the upper surface of the permanent magnet; the axis of the Hall position sensor forms an included angle Theta with the upper surface of the permanent magnet; the detection surface of the Hall position sensor faces the upper surface of the permanent magnet; a magnetization lining plate is arranged on the back surface of the Hall position sensor; the Hall position sensor is connected with a printed circuit board (PCB) through a non-magnetization bracket; the PCB is connected with the stator core through a PCB bracket; and a signal wire and a power cord of the Hall position sensor are electrically connected with a preposed processing circuit on the PCB. The device has the characteristics of simple and rational structure, high sensing capability and wide application range.

The invention discloses a manufacturing method and a structure of a long-distance radio frequency identification metal product. Ultrahigh-frequency radio frequency identification (UHF RFID) can be applied to various metal products without interference; electromagnetic waves emitted by an emitter are received by a metal primary antenna on the metal product; by utilizing a resonant cavity in the metal primary antenna and a secondary antenna of an electronic tag module patch, resonance and sensing are generated to transmit a signal to a radio frequency identification (RFID) wafer so as to achieve a long-distance reading and sending effect; when fragment cutting lines at the position of the secondary antenna are disassembled, the secondary antenna is damaged and loses efficacy; the electronic tag module patch is bound by an adhesive and sealed in the metal primary antenna; if the electronic tag module patch is disassembled, the effect that the secondary antenna is damaged and loses efficacy can also be caused, so that the metal product has an RFID function and also has an anti-copy efficacy.

A sensing fiber adapted to transmit a sensing light along a path and sense an object is provided. The fiber includes a core, a plurality of photonic crystal structures surrounding the core, a sensing surface and a metal sensing layer. The core is located at the center of the fiber. The photonic crystal structures extend along the path. The sensing surface extends along part of the path and adjacent to the core, and the metal sensing layer having a plurality of metal grating structure is disposed on the sensing surface. When the fiber is sensing the object, the metal sensing layer is located between the sensing surface and the object, and part of the sensing light will be converted into a signal light by the object on the metal sensor layer. A sensing device is also provided.

A stray-light-coupled biometrics sensing module includes a light-transparent body, a display unit and an optical module. The light-transparent body has a front side and a backside. The front side is configured to support an organic object thereon. The display unit attached to the backside of the light-transparent body displays a frame. The optical module is attached to the backside of the light-transparent body through an adhesive, and is disposed adjacent to the display unit. First light rays of the frame emitted from an eye-viewing screen couple into the organic object through the light-transparent body. After travelling a short distance in the organic object, the first light rays couple out of the organic object and re-enter the light-transparent body as second light rays entering the optical module. The optical module senses the second light rays to generate a biometrics image signal. An electronic apparatus is also disclosed.

The invention discloses a distance detection induction device, which comprises a shell, focusing lenses, a circuit board which is provided with a plurality of electronic components, an emitting device for emitting infrared light rays and a receiving device for receiving and inducing reflected infrared light rays, wherein the shell comprises a main body part and two circular openings which are positioned on the top surface of the main body part; the lenses comprise an emitting lens and a receiving lens which are arranged on the two openings of the shell; the circuit board is arranged in the main body part of the shell; the emitting device is an infrared light emitting diode for emitting the infrared light rays to the emitting lens; and the receiving device is a distance detection induction module for inducing the reflected light rays focused by the receiving lens. The distance detection induction device also comprises an emitting light ray guiding device which is arranged between the emitting lens and the emitting device and comprises a small circular hole arranged at the position of a transmitting tube core of the emitting device. The distance detection induction device has the advantages of higher detection precision and improvement of the induction performance of the whole machine.

The invention discloses a low-lighting-position and multidimensional lighting street lamp. The street lamp is lighting equipment designed according to 'a low-lighting-position and multidimensional road lighting mode' invented by the inventor. The low-lighting-position and multidimensional lighting street lamp comprises a lamp body, a light source, a fixing device and a pipeline. Lighting light sources for different purposes and the lamp are integrated, and the light sources and circuits are placed in a hollow lamp body to form the integrated street lamp. Problems of glare and invalid lighting are solved, and energy consumption is greatly reduced. The conventional mainstream snake-head lamp lighting mode is eliminated, and a simple replacement mode of replacing other light sources by using light-emitting diode (LED) lamps is also eliminated. Because the low-power LED light source is used for lighting in a dispersion manner, longitudinal uniformity degree is increased, and the problem that the conventional high-power LED street lamp is poor in heat dissipation is solved. Compared with the traditional street lamp, the low-lighting-position and multidimensional lighting street lamp has the advantages that integration level is high, the lamp is convenient to assemble and disassemble in fields, daily maintenance is facilitated, and a lamp pole is not required; and the one-time investment and the running cost of the low-lighting-position and multidimensional lighting street lamp are greatly reduced compared with those of the conventional mainstream road lighting system.

A chip-type sensor against ESD and stress damages and contamination interference includes a substrate structure and a protection layer covering over the substrate structure. The protection layer includes, from bottom to top, a first layer for providing a first stress against the substrate structure, a second layer for providing a second stress against the substrate structure, and a third layer for providing a third stress against the substrate structure. The first stress and the third stress belong to one of a tensile stress and a compressive stress, and the second stress belongs to the other of the tensile stress and the compressive stress.

The invention relates to pelteobagrus fulvdraco sperm ultralow temperature freezing storage and recovery method. Parent pelteobagrus fulvdraco which is in good shape and good growth, has no disease and is sexually mature is selected, 30Mug / kg LHRH-A2 intraperitoneal injection is carried out to induce sperm increasing, after 36 hours, dissection is carried out to obtain spermary, and the spermary is cut into pieces in a clean mortar cooled in a refrigerator at 4 DEG C in advance, the pieces are diluted by Ringers solution in the proportion of 1:6, balancing is carried out for 30min at 4 DEG C, 10% methyl alcohol is added, and mixing to be uniform is carried out, packaging is carried out, balancing is carried out for 10min 6cm above liquid nitrogen surface, and balancing is carried out for 5min on the liquid nitrogen surface, and then the product is thrown into liquid nitrogen to be stored. Water bath ate 37 DEG C is carried out, activation solution SM is used for activation, pelteobagrus fulvdraco roe is extruded into a container, frozen sperm is added in drops in the sperm roe quantity ratio of 105:1, stirring to be uniform is carried out, then appropriate activation solution SM is added in drops, and stirring to be uniform is carried out, so that fertilization of roe is carried out. The sperm stored by the invention has high quality, has insemination capability and has important theoretical significance and application value on seed quality saving, inheritance breeding, sustainable culture and disease control of pelteobagrus fulvdraco.

A fan includes a motor and an impeller. The motor drives the impeller to rotate and includes a base, a bearing, a stator, a rotor and a magnetic element. The central portion of the base is extended to form a bushing for accommodating the bearing therein. The stator telescopes around the bushing. The rotor is disposed corresponding to the stator and has a shaft passing through the bearing. The magnetic element is disposed at the bottom of the bushing and located adjacent to one end of the shaft.

The present invention discloses method of utilizing exogenic chemical matter to induce dragon tree to generate dragon's blood. The method includes drilling holes in dragon tree trunk over three years old and dragon tree branch over two years old and injecting inducing matter, cutting longitudinal slots in the trunk and branch and filling the slots with absorbent cotton soaked with the inducing matter, wrapping the hole and the slot with transparent plastic film, cutting the branch or trunk becoming red completely with generated dragon's blood, drying and crushing, and extracting dragon's blood with methanol. The said method has obvious inducing effect and greatly shortened dragon's blood producing period, and is suitable for large scale dragon's blood production.

A method for inducing the embryonic callus with high inducing effect and its special culture medium are disclosed. Said special culture medium DCR contains proportionally VB1, VB6, nicotinic acid, inositol, glutamine, hydrolytic casein, 2,4-dichlorophenoxyacetic acid, 6-BA, cane sugar and agar.

The invention provides a fiber felt manufacturing device and relates to fiber felt. The fiber manufacturing device comprises a spinning box, a vibration generating device, a vibration transmitting system, a solution supply system, a collecting device, a high-voltage power supply, inducing pieces and fixing pieces. The interior of the spinning box is divided into a vibration transmitting chamber and a solution trough, the vibration transmitting system is arranged in the vibration transmitting chamber, and the vibration transmitting system is provided with a vibration output shaft, a connecting seat and a vibration transmitting block. The solution supply system is provided with a solution storage tank and a metering pump. The vibration output shaft is fixed to the spinning box through the connecting seat, the shaft end of the vibration output shaft is connected with one end of the vibration transmitting block, and the inducing pieces are hinged to the other end face of the vibration transmitting block. Inducing piece protrusions are arranged on the tops of the inducing pieces, and fixing piece protrusions are arranged on the tops of the fixing pieces. A concave fixing block is arranged in the solution trough, and the fixing pieces are fixed in grooves of the concave fixing block. The metering pump is communicated with the solution trough through a solution supply pipe, solution is supplied to the solution trough through the metering pump, the collecting device is arranged over the solution trough, and the collecting device is electrically connected with the output end of the high-voltage power supply.

An integrated container-type torque sensor motor is provided. Disposed on a motor housing along the direction of a motor shaft is a hollow cavity formed by a ring-shaped protrusion; contained in the hollow cavity is a fixed guiding slip ring; the fixed guiding slip ring dynamically matches with a floating sensor ring assembly having ratchet teeth and a magnetic steel piece; the ratchet teeth of a flywheel mating with the cogging distributed in a ring shape in a sensor ring having ratchet teeth; disposed on the motor shaft is a Hall element, the magnetic steel piece cooperating with the Hall element by means of magnetic induction, thereby outputting an electric signal to control a vehicle to enhance the force for rotation. For this motor, all Hall elements are disposed on the motor housing, thereby solving the conflict between function configuration and space occupation, and enabling significant magnetic induction effects.

The invention discloses a radio frequency identification locating device and a method thereof, which can identify and locate at least one radio frequency identification tag. The device comprises an emitting mould train, a capacitor, a plurality of pairs of induction mould trains, an identification mould train and a plurality of pairs of line mould trains. The emitting mould train emits a frequency. The first switch units of the induction mould trains carry out conduction according to the frequency so that a first induction coil forms a flux with the capacitor, and the first induction coil induces the identification signals of the radio frequency identification tags. A second induction coil is used for improving the flux. The identification mould train receives the identification signals for identifying and locating the radio frequency identification tags. Each line mould train is connected with the emitting mould train, the induction mould trains, the capacitor and the identification mould train, and transmits the identification signals. All of the induction coils are matched with each other by virtue of the approximately equal length of each line mould train.