CN104237934A - Differential piezoelectric digital geophone - Google Patents
Differential piezoelectric digital geophone Download PDFInfo
- Publication number
- CN104237934A CN104237934A CN201410515341.2A CN201410515341A CN104237934A CN 104237934 A CN104237934 A CN 104237934A CN 201410515341 A CN201410515341 A CN 201410515341A CN 104237934 A CN104237934 A CN 104237934A
- Authority
- CN
- China
- Prior art keywords
- differential
- signal
- shielding case
- digital
- piesoelectric
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Geophysics And Detection Of Objects (AREA)
Abstract
The invention discloses a differential piezoelectric digital geophone. The differential piezoelectric digital geophone comprises a geophone core which comprises a cylindrical shielding case, a base, piezoelectric elements, mass blocks, a signal conditioning unit, a signal preprocessing unit, feed-through capacitors and outgoing cables. The base is arranged in the center of the shielding case and in rigid connection with the shielding case; the two groups of piezoelectric elements are symmetrically attached to two sides of the base, and the two mass blocks are symmetrically attached to the outer sides of one group of piezoelectric elements; the two groups of piezoelectric elements are connected with an input end of the signal conditioning unit through outgaining electrodes at two ends of the piezoelectric elements, an output end of the signal conditioning unit is connected with an input end of the signal processing unit, and an output end of the signal processing unit is connected with the outgaining cables through the feed-through capacitors. By means of the geophone core in the symmetrical structure, differential signal output and direct digital processing of signals, the differential piezoelectric digital geophone has the advantages of high flexibility, high antijamming capability, wide dynamic range, portability, durability and the like.
Description
Technical field
The invention belongs to field of seismic exploration, be specifically related to a kind of differential piesoelectric digital seismometer.
Background technology
Method of seismic exploration has very important Research Significance exploring for oil, in rock gas and other mineral resources and engineering detecting, geological hazards prediction etc.The key technical indexes of seismic prospecting instrument is determined by seismoreceiver.The wave detector of moving-coil structure is still the most widely used seismoreceiver in domestic and international seismic prospecting at present.But due to the mechanical features that it is intrinsic, for the precision that can reach relative to existing seismic instrument and dynamic range, the shortcomings such as it has that sensitivity is low, dynamic range is little, quality and volume is comparatively large, poor anti jamming capability, and to spring material require high, manufacturing process is complicated.The wave detector of piezoelectric type structure is also applied to some extent in water-land seismic exploration, achieves good effect, but also there is the parts that have much room for improvement such as quality and volume are comparatively large, insufficient sensitivity is high, poor anti jamming capability.
Seismoreceiver is by land in seismic prospecting, when geophone offset is larger, signal overall magnitude diminishes, the radio-frequency component particularly wherein comprised will decay to tiny signal, in order to prevent signal to noise ratio (S/N ratio) from worsening further in picking up signal transmitting procedure, solution of should starting with from the sensitivity and antijamming capability aspect improving seismoreceiver.
Summary of the invention
The technical problem to be solved in the present invention is, for overcoming existing seismoreceiver above shortcomings, a kind of differential piesoelectric digital seismometer is provided, adopts the detector core body of symmetrical structure, in the finite space, increase sensitivity and the antijamming capability of wave detector.
The present invention for solving the problems of the technologies described above adopted technical scheme is:
Differential piesoelectric digital seismometer, comprise detector core body, detector core body is made up of drum type shielding case, pedestal, piezoelectric element, mass, signal condition unit, Signal Pretreatment unit, feedthrough capacitor, outgoing cable, described pedestal is arranged at shielding case inside center, and pedestal and shielding case are rigidly connected; Described piezoelectric element is provided with two groups, and two groups of piezoelectric element symmetries are close to and are arranged on pedestal both sides, and described mass is provided with two, and two masses respectively symmetry are close to and are arranged on outside one group of piezoelectric element; Described two groups of piezoelectric elements are connected with the input end of signal condition unit respectively by the extraction electrode at respective two ends, the output terminal of signal condition unit is connected with the input end of Signal Pretreatment unit, and the output terminal of Signal Pretreatment unit is connected with outgoing cable by feedthrough capacitor.
By such scheme, described shielding case adopts certain thickness aluminium alloy or alumina based material to make.
By such scheme, described piezoelectric element is formed by stacking by multi-layer piezoelectric sheet.
By such scheme, described two groups of piezoelectric element structures identical (ensureing that its performance is identical).
By such scheme, described feedthrough capacitor is directly installed on shielding case.
By such scheme, described signal condition unit is made up of the differential amplifier be connected successively, wave filter and A/D converter.
By such scheme, described Signal Pretreatment unit is made up of the complex programmable logic device (CPLD) be connected successively and digital signal processor DSP.
By such scheme, described signal condition unit, Signal Pretreatment unit are all encapsulated in shielding case.
Principle of work of the present invention: two groups of piezoelectric elements for generation of the alternating voltage reflecting surface seismic vibration characteristics, and form pair of differential signal, and two masses are used for the motion of perception seismic event.In practical work process, when extraneous vibration, as knocked detector core body with little steel ball, due to the piezoelectric effect of piezoelectric patches, its two ends extraction electrode will export the voltage signal be directly proportional to vibration signal.Because two groups of piezoelectric element symmetries are arranged on pedestal both sides, the AC portion of the voltage signal of two groups of piezoelectric element generations will form pair of differential signal, the alternating voltage waveform almost symmetry exported by oscillograph, phase is about 180 degree, constitutes pair of differential signal preferably.The detector core body design of this symmetrical structure, can increase the sensitivity of wave detector in limited space, and its differential wave exported has stronger antijamming capability relative to single-ended signal simultaneously.Improve dynamic range and the antijamming capability of wave detector.The differential wave exported directly is admitted in the inner integrated signal condition unit of wave detector, digital signal is converted into through differential amplification, filtering and A/D, this digital signal is admitted to Signal Pretreatment unit further, after digital filtering, FFT conversion process, carry out long range propagation by the feedthrough capacitor be arranged on shielding case through outgoing cable.
Tool of the present invention has the following advantages:
1, the feature of seismic exploration in combination, piezoelectric element symmetry is arranged on pedestal two ends, adopt the detector core body of symmetrical structure, the sensitivity of wave detector is increased and output difference dynamic formula voltage signal in limited space, the differential wave amplitude after follow-up difference processing exported doubles, and the identical all kinds of neighbourhood noises of aliasing, common mode interference signal are then cancelled out each other in two differential waves, the single-ended signal exported relative to traditional seismoreceiver has stronger antijamming capability, improves the antijamming capability of detector core body self;
2, shielding case adopts certain thickness aluminium alloy or alumina based material to make, Portable durable, can shield the interference of most of electric field, magnetic field and electromagnetic field; Piezoelectric element adopts multi-layer piezoelectric sheet to be formed by stacking, and adds the amplitude of output voltage signal; Feedthrough capacitor is high frequency interference on filtering wire, improves the signal fidelity of wave detector;
3, signal condition unit, Signal Pretreatment unit are all encapsulated in shielding case, the seismic signal (differential type simulating signal) detected exports carry out the process such as signal condition, analog/digital conversion, digital filtering in wave detector after again, digitized process is directly directly processed in detector core body, avoid seismic signal and introduce interference distortion in long range propagation, remain the effective constituent of weak signal, improve dynamic range and the antijamming capability of wave detector;
4, this seismoreceiver has the advantages such as highly sensitive, antijamming capability is strong, wide dynamic range, Portable durable, and seismoreceiver is more reliable and extensive in field application such as down-hole seam seismic exploration, land seismic explorations.
Accompanying drawing explanation
Fig. 1 is the one-piece construction schematic diagram of differential piesoelectric digital seismometer of the present invention;
Fig. 2 is the pair of differential signal schematic representation that wave detector two ends of the present invention piezoelectric exports;
Fig. 3 is the structural representation of the inner integrated signal condition unit of wave detector of the present invention and Signal Pretreatment unit;
Fig. 4 is the structural representation of the shielding case of differential piesoelectric digital seismometer of the present invention;
In figure, 1-shielding case, 2-pedestal, 3-piezoelectric element, 4-mass, 5-signal condition unit, 6-Signal Pretreatment unit, 7-feedthrough capacitor, 8-outgoing cable.
Embodiment
Below in conjunction with drawings and Examples, the present invention is described in detail.
With reference to shown in Fig. 1, differential piesoelectric digital seismometer of the present invention, comprise detector core body, detector core body by drum type shielding case 1(as detector core body framework), pedestal 2, piezoelectric element 3, mass 4, signal condition unit 5, Signal Pretreatment unit 6, feedthrough capacitor 7, outgoing cable 8 form, described pedestal 2 is arranged at shielding case 1 inside center, pedestal 2 and shielding case 1 are rigidly connected (piezoelectric element 3 changing detector core body inside is convenient in pedestal 2 inspection for convenience detach); Described piezoelectric element 3 is provided with two groups, two groups of piezoelectric element 3 symmetries are close to and are arranged on pedestal 2 both sides, described mass 4 is provided with two, two masses 4 respectively symmetry are close to and are arranged on (a set of piezoelectric element 3 and mass 4 are respectively installed in intermediate base 2 both sides, and the symmetria bilateralis of piezoelectric element 3, mass 4 opposite base 2 is arranged) outside one group of piezoelectric element 3; Described two groups of piezoelectric elements 3 are connected with the input end of signal condition unit 5 respectively by the extraction electrode at respective two ends, the output terminal of signal condition unit 5 is connected with the input end of Signal Pretreatment unit 6, the output terminal of Signal Pretreatment unit 6 is connected with outgoing cable 8 (in Fig. 1, the wire that the extraction electrode that piezoelectric element 3 is connected with signal condition unit 5, signal condition unit 5 are connected with Signal Pretreatment unit 6 is all encapsulated in shielding case 1 and does not mark) by feedthrough capacitor 7.
Described shielding case 1 adopts certain thickness aluminium alloy or alumina based material to make, Portable durable, can shield the interference of most of electric field, magnetic field and electromagnetic field.
Described piezoelectric element 3 is formed by stacking by multi-layer piezoelectric sheet, to increase the amplitude of output signal, two groups of piezoelectric element 3 structures are identical, ensure that its performance is identical.
Described feedthrough capacitor 7 is arranged on shielding case 1, for the high frequency interference on filtering outgoing cable 8, improves the signal fidelity of wave detector.
Described signal condition unit 5 is made up of the differential amplifier be connected successively, wave filter and A/D converter.
Described Signal Pretreatment unit 6 is made up of the complex programmable logic device (CPLD) be connected successively and digital signal processor DSP.
Described signal condition unit 5, Signal Pretreatment unit 6 are all encapsulated in shielding case 1.
Two groups of piezoelectric elements 3 for generation of the alternating voltage of reflection surface seismic vibration characteristics, and form pair of differential signal, and two masses 4 are for the motion of perception seismic event.In practical work process, when extraneous vibration, as knocked detector core body with little steel ball, due to the piezoelectric effect of the piezoelectric patches of piezoelectric element 3, its two ends extraction electrode will export the voltage signal be directly proportional to vibration signal.Because two groups of piezoelectric element 3 symmetries are arranged on pedestal 2 both sides, the AC portion of the voltage signal of two groups of piezoelectric element 3 generations will form pair of differential signal, by the alternating voltage waveform almost symmetry that oscillograph shown in Fig. 2 exports, phase is about 180 degree, constitutes pair of differential signal preferably.The detector core body design of this symmetrical structure, can increase the sensitivity of wave detector in limited space, and its differential wave exported has stronger antijamming capability relative to single-ended signal simultaneously.Improve dynamic range and the antijamming capability of wave detector.The differential wave exported directly is admitted in the inner integrated signal condition unit 5 of wave detector, digital signal is converted into through differential amplification, filtering and A/D, this digital signal is admitted to Signal Pretreatment unit 6 further, after digital filtering, FFT conversion process, carry out long range propagation by the feedthrough capacitor 7 be arranged on shielding case 1 through outgoing cable 8.
The composition of the inner integrated signal condition unit 5 of detector core body of the present invention and Signal Pretreatment unit 6 as shown in Figure 3.
The shielding case 1(detector core body framework of differential piesoelectric digital seismometer of the present invention) structure as shown in Figure 4.
Last Signal Pretreatment unit is reserved with control and data-interface, and the output signal of convenient wave detector is in the future docked with advanced mechanics of communication (such as radio sensing network); Detector core body is installed outer protection shell again and is then completed the global design of wave detector after being connected with cable.
Above-describedly be only preferred embodiment of the present invention, certainly can not limit the interest field of the present invention with this, therefore according to the equivalence change that the present patent application the scope of the claims is done, still belong to protection scope of the present invention.
Claims (8)
1. differential piesoelectric digital seismometer, it is characterized in that, comprise detector core body, detector core body is made up of drum type shielding case, pedestal, piezoelectric element, mass, signal condition unit, Signal Pretreatment unit, feedthrough capacitor, outgoing cable, described pedestal is arranged at shielding case inside center, and pedestal and shielding case are rigidly connected; Described piezoelectric element is provided with two groups, and two groups of piezoelectric element symmetries are close to and are arranged on pedestal both sides, and described mass is provided with two, and two masses respectively symmetry are close to and are arranged on outside one group of piezoelectric element; Described two groups of piezoelectric elements are connected with the input end of signal condition unit respectively by the extraction electrode at respective two ends, the output terminal of signal condition unit is connected with the input end of Signal Pretreatment unit, and the output terminal of Signal Pretreatment unit is connected with outgoing cable by feedthrough capacitor.
2. differential piesoelectric digital seismometer according to claim 1, is characterized in that, described shielding case adopts certain thickness aluminium alloy or alumina based material to make.
3. differential piesoelectric digital seismometer according to claim 1, is characterized in that, described piezoelectric element is formed by stacking by multi-layer piezoelectric sheet.
4. the differential piesoelectric digital seismometer according to claim 1 or 3, is characterized in that, described two groups of piezoelectric element structures are identical.
5. differential piesoelectric digital seismometer according to claim 1, is characterized in that, described feedthrough capacitor is directly installed on shielding case.
6. differential piesoelectric digital seismometer according to claim 1, is characterized in that, described signal condition unit is made up of the differential amplifier be connected successively, wave filter and A/D converter.
7. differential piesoelectric digital seismometer according to claim 1, is characterized in that, described Signal Pretreatment unit is made up of the complex programmable logic device (CPLD) be connected successively and digital signal processor DSP.
8. differential piesoelectric digital seismometer according to claim 1, is characterized in that, described signal condition unit, Signal Pretreatment unit are all encapsulated in shielding case.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410515341.2A CN104237934A (en) | 2014-09-29 | 2014-09-29 | Differential piezoelectric digital geophone |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410515341.2A CN104237934A (en) | 2014-09-29 | 2014-09-29 | Differential piezoelectric digital geophone |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN104237934A true CN104237934A (en) | 2014-12-24 |
Family
ID=52226378
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410515341.2A Pending CN104237934A (en) | 2014-09-29 | 2014-09-29 | Differential piezoelectric digital geophone |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN104237934A (en) |
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104749615A (en) * | 2015-03-18 | 2015-07-01 | 中南大学 | Radio detector for seismic exploration or vibration test |
| CN105223606A (en) * | 2015-09-06 | 2016-01-06 | 中国科学院地质与地球物理研究所 | Land piezoelectric seismometer core body |
| CN105388514A (en) * | 2015-10-28 | 2016-03-09 | 中国石油天然气股份有限公司 | Seismic omnidirectional vector electrostatic suspension detector |
| CN107091976A (en) * | 2017-05-23 | 2017-08-25 | 北京兴泰学成仪器有限公司 | Ultrasonic sensor |
| CN107870350A (en) * | 2017-12-13 | 2018-04-03 | 中国地质大学（武汉） | A kind of differential type bimorph geophone core body and piezoelectric seismometer |
| CN107884817A (en) * | 2017-12-13 | 2018-04-06 | 中国地质大学（武汉） | A kind of piezoelectric seismometer |
| CN107884816A (en) * | 2017-12-13 | 2018-04-06 | 中国地质大学（武汉） | A kind of piezoelectric seismometer |
| CN107884818A (en) * | 2017-12-13 | 2018-04-06 | 中国地质大学（武汉） | A kind of piezoelectric seismometer |
| CN109283573A (en) * | 2018-09-27 | 2019-01-29 | 西安明天仪器有限公司 | MEMS type Omnibearing earthquake auto wave detector |
| CN110133711A (en) * | 2018-02-08 | 2019-08-16 | 东营市智威石油技术有限责任公司 | A kind of piezoelectric type acceleration type wave detector machine core |
| CN110244348A (en) * | 2019-06-06 | 2019-09-17 | 山东科技大学 | A kind of photoelectric composite geophone and detection system |
| US10578757B2 (en) | 2015-10-28 | 2020-03-03 | Petrochina Company Limited | Omnidirectional vector seismic data processing method and apparatus, computer-readable storage medium and device |
| US10739477B2 (en) | 2015-10-28 | 2020-08-11 | Petrochina Company Limited | Omnidirectional vector geophone |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02309284A (en) * | 1989-05-24 | 1990-12-25 | Fujitsu Ltd | Seismic intensity meter |
| CN2439034Y (en) * | 2000-08-24 | 2001-07-11 | 西安石油勘探仪器总厂 | Terrestrial piezoelectric ceramic seismic detector |
| CN2488068Y (en) * | 2001-03-27 | 2002-04-24 | 南京师范大学 | Differential piezoelectric acceleration sensor |
| CN1418312A (en) * | 2000-02-15 | 2003-05-14 | 尼克斯特法斯公司 | Voltage sensor |
| US20040252585A1 (en) * | 2001-10-10 | 2004-12-16 | Smith Dexter G. | Digital geophone system |
| CN101788684A (en) * | 2010-04-09 | 2010-07-28 | 中国科学院地质与地球物理研究所 | Piezoelectric digital seismometer on land |
-
2014
- 2014-09-29 CN CN201410515341.2A patent/CN104237934A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02309284A (en) * | 1989-05-24 | 1990-12-25 | Fujitsu Ltd | Seismic intensity meter |
| CN1418312A (en) * | 2000-02-15 | 2003-05-14 | 尼克斯特法斯公司 | Voltage sensor |
| CN2439034Y (en) * | 2000-08-24 | 2001-07-11 | 西安石油勘探仪器总厂 | Terrestrial piezoelectric ceramic seismic detector |
| CN2488068Y (en) * | 2001-03-27 | 2002-04-24 | 南京师范大学 | Differential piezoelectric acceleration sensor |
| US20040252585A1 (en) * | 2001-10-10 | 2004-12-16 | Smith Dexter G. | Digital geophone system |
| CN101788684A (en) * | 2010-04-09 | 2010-07-28 | 中国科学院地质与地球物理研究所 | Piezoelectric digital seismometer on land |
Non-Patent Citations (1)
| Title |
|---|
| 吕公河: "地震勘探检波器原理和特性及有关问题分析", 《石油勘探》 * |
Cited By (20)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104749615B (en) * | 2015-03-18 | 2017-06-30 | 中南大学 | A kind of seismic prospecting or vibration test wave detector |
| CN104749615A (en) * | 2015-03-18 | 2015-07-01 | 中南大学 | Radio detector for seismic exploration or vibration test |
| CN105223606A (en) * | 2015-09-06 | 2016-01-06 | 中国科学院地质与地球物理研究所 | Land piezoelectric seismometer core body |
| US10739477B2 (en) | 2015-10-28 | 2020-08-11 | Petrochina Company Limited | Omnidirectional vector geophone |
| CN105388514B (en) * | 2015-10-28 | 2017-12-05 | 中国石油天然气股份有限公司 | Seismic omnidirectional vector electrostatic suspension detector |
| CN105388514A (en) * | 2015-10-28 | 2016-03-09 | 中国石油天然气股份有限公司 | Seismic omnidirectional vector electrostatic suspension detector |
| US10718875B2 (en) | 2015-10-28 | 2020-07-21 | Petrochina Company Limited | Omnidirectional vector electrostatic levitation geophone |
| US10578757B2 (en) | 2015-10-28 | 2020-03-03 | Petrochina Company Limited | Omnidirectional vector seismic data processing method and apparatus, computer-readable storage medium and device |
| CN107091976A (en) * | 2017-05-23 | 2017-08-25 | 北京兴泰学成仪器有限公司 | Ultrasonic sensor |
| CN107091976B (en) * | 2017-05-23 | 2024-03-01 | 北京兴泰学成仪器有限公司 | Ultrasonic sensor |
| CN107884817A (en) * | 2017-12-13 | 2018-04-06 | 中国地质大学（武汉） | A kind of piezoelectric seismometer |
| CN107884818A (en) * | 2017-12-13 | 2018-04-06 | 中国地质大学（武汉） | A kind of piezoelectric seismometer |
| CN107884816A (en) * | 2017-12-13 | 2018-04-06 | 中国地质大学（武汉） | A kind of piezoelectric seismometer |
| CN107870350B (en) * | 2017-12-13 | 2023-12-15 | 中国地质大学（武汉） | Differential dual-piezoelectric-patch geophone core and piezoelectric geophone |
| CN107870350A (en) * | 2017-12-13 | 2018-04-03 | 中国地质大学（武汉） | A kind of differential type bimorph geophone core body and piezoelectric seismometer |
| CN107884817B (en) * | 2017-12-13 | 2023-09-26 | 中国地质大学（武汉） | Piezoelectric geophone |
| CN110133711A (en) * | 2018-02-08 | 2019-08-16 | 东营市智威石油技术有限责任公司 | A kind of piezoelectric type acceleration type wave detector machine core |
| CN109283573A (en) * | 2018-09-27 | 2019-01-29 | 西安明天仪器有限公司 | MEMS type Omnibearing earthquake auto wave detector |
| CN110244348A (en) * | 2019-06-06 | 2019-09-17 | 山东科技大学 | A kind of photoelectric composite geophone and detection system |
| WO2020243993A1 (en) * | 2019-06-06 | 2020-12-10 | 山东科技大学 | Photoelectric composite geophone and detection system |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104237934A (en) | Differential piezoelectric digital geophone | |
| CN101788684B (en) | Piezoelectric digital seismometer on land | |
| CN103513273B (en) | The land digital seismoreceivers of four components | |
| CN103969690B (en) | A kind of magnetic field sensor | |
| CN103792568B (en) | MEMS geophone | |
| CN104749615B (en) | A kind of seismic prospecting or vibration test wave detector | |
| EP2630521A2 (en) | Methods and apparatus for geophysical prospecting to detect bodies of fluids in underground formations | |
| CN106199687A (en) | Simple component geophone | |
| CN203465426U (en) | Piezoelectric type universal geophone | |
| CN108089231B (en) | Three-dimensional gradient vector method transient electromagnetic instrument and application thereof | |
| CN200989945Y (en) | Multipurpose acceleration type piezoelectric earthquick detector | |
| CN106656080B (en) | Front-end circuit system of elastic wave CT instrument | |
| CN207780260U (en) | A kind of piezoelectric seismometer | |
| CN207851319U (en) | A kind of both arms piezoelectric seismometer | |
| Li et al. | Analysis of geophone properties effects for land seismic data | |
| CN207817222U (en) | A kind of piezoelectric seismometer | |
| CN207908704U (en) | A kind of differential type bimorph geophone core and piezoelectric seismometer | |
| CN206211953U (en) | A kind of front end circuit system of elastic wave CT instrument | |
| CN212008956U (en) | High-precision detector | |
| CN101930078A (en) | Anti-electromagnetic interference sensor | |
| CN205157039U (en) | Exempt from to insert and exempt from couplant elastic wave wave detector | |
| Xing et al. | Design and research on piezoelectric acceleration geophone | |
| CN111722271B (en) | Annular cantilever piezoelectric detector core | |
| CN104101516B (en) | Miniature magnetoelectricity velometer | |
| CN208140951U (en) | Magnetic suspension reed force balance type geophone |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20141224 |