CN104713913A - Underground pipeline testing method based on strain membranes - Google Patents
Underground pipeline testing method based on strain membranes Download PDFInfo
- Publication number
- CN104713913A CN104713913A CN201510154766.XA CN201510154766A CN104713913A CN 104713913 A CN104713913 A CN 104713913A CN 201510154766 A CN201510154766 A CN 201510154766A CN 104713913 A CN104713913 A CN 104713913A
- Authority
- CN
- China
- Prior art keywords
- resistance
- strain
- strain film
- ring
- data acquisition
- 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
- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
Abstract
The invention relates to the technical field of underground pipeline survey and provides an underground pipeline testing method based on strain membranes. The method comprises the following steps: adhering N-numbered ring-shaped strain membranes to the surface of a pipeline uniformly, and adhering a waterproof membrane to the surface of each ring-shaped strain membrane, wherein N is not less than 2; arranging an insulating membrane isolator between two adjacent ring-shaped strain membranes; connecting every n-numbered ring-shaped strain membranes by conductors in series or in parallel to form strain membrane groups, wherein n is not less than 1 and not more than N; arranging n-numbered dynamic strain gauges, data acquisition systems, central processing units and wireless communication modules, which are connected with each other in sequence, to form operational circuits; connecting each strain membrane group with resistors R2, R3 and R4 end to end in sequence to form bridge circuits, wherein each bridge circuit is connected with each operational circuit; all the operational circuits communicate with a background database and a monitoring center via a wireless communication network. The method is accurate in positioning.
Description
Technical field
The present invention relates to underground pipeline survey technical field, particularly relate to a kind of earth mat test pipeline method based on strain film.
Background technology
Along with the development of urban construction, scale and the kind of underground utilities distribution increase severely day by day.Underground utilities comprise cable, heat supply pipeline, water supply line, gas pipeline etc., because it is embedded in underground, even if once break etc. and cannot locate at once, make troubles to the maintenance of managerial personnel.More or even after cannot locating at once cause more serious danger, cause the loss of personnel's property.Buried pipe line length occupy dark unglazed underground, mostly according to sensor, the measurement of the leakage scale of construction is responded to even if leakage etc. occurs for it, and be in the consideration of cost, arranging of sensor all keeps at a certain distance away, whole pipeline cannot be spread all over, its induction speed and inductive effects reduce greatly, even and if crack tiny on some pipelines just cannot sense, and need rear just likely the responding to of the situation generations such as leakage, and often tiny crack repairing is easily simple, and once after causing leakage, then probably cause the heavy losses of property, even cause casualties.Therefore, the how accurately small fault position of positioningly underground pipelines, and the feedback that is accurately out of order, even if line losses was just avoided in the flaw stage, minimizing property and personal casualty loss substantially.
Summary of the invention
Solve the problems of the technologies described above, the invention provides a kind of earth mat test pipeline system based on strain film, coordinating is sticked at the strain film of pipe surface, and design an equivalent electrical circuit, detect strain film to the change of circuitous resistance, thus detect the position of trouble spot, even if even if the most small loss located exactly, for pipeline maintenance provides detection and location function the most timely.
Present invention also offers a kind of earth mat test pipeline method based on strain film, by the strain film that is sticked at pipe surface, and coordinate related circuit to respond to the crack on pipeline and miniature deformation, thus accurate targeted duct surface crack and miniature deformation, there is provided the maximized time to ensure to pipeline maintenance, and greatly reduce pipeline maintenance cost.
In order to achieve the above object, the technical solution adopted in the present invention is, a kind of earth mat test pipeline system based on strain film, comprise the strain film be sticked in pipeline appearance, and be arranged on the waterproofing membrane of strain film appearance, described strain film is N number of ring-type strain film, wherein N >=2, each ring-type strain film is close to and is located at pipeline circumferential hoop outer wall, there is between adjacent two ring-type strain films dielectric film isolation, also comprise dynamic strain indicator, data acquisition system (DAS), central processing unit and wireless communication module, strain film group is become by wired in series or parallel connection between every n ring-type strain film, wherein 1≤n≤N, strain film group and resistance R2, R3, R4 is sequentially end-to-end formation bridge circuit, and connect dynamic strain indicator successively, data acquisition system (DAS) and central processing unit, described wireless communication module and central processing unit are electrically connected, wireless communication module is communicated with background data base and Surveillance center by cordless communication network.
Further, described strain film equivalent resistance is ri, resistance ri and resistance R2, R3, R4 are sequentially end-to-end formation bridge circuit, wherein the common connection end of resistance ri and resistance R2 is a end, the common connection end of resistance ri and resistance R3 is b end, the common connection end of resistance R3 and resistance R2 is c end, and the common connection end of resistance R2 and resistance R4 is d end, and b end is connected AC power U with d end
i, a end and c end are voltage output end U
oand be connected with dynamic strain indicator input end, dynamic strain indicator output terminal is connected with data acquisition system (DAS) input end, and data acquisition system (DAS) output terminal is connected with central processing unit.
Further, also comprise power circuit, described power circuit input end connects AC power U
i, described power circuit exports direct supply and is respectively dynamic strain indicator, data acquisition system (DAS) and central processing unit and wireless communication module power supply.
Based on an earth mat test pipeline method for strain film, comprise the following steps:
Evenly to be sticked N number of ring-type strain film in pipeline appearance, wherein N >=2, and to be sticked waterproofing membrane in each ring-type strain film appearance,
And dielectric film isolation is set between adjacent two ring-type strain films,
Strain film group is become by wired in series or parallel connection, wherein 1≤n≤N between every n ring-type strain film,
N dynamic strain indicator, data acquisition system (DAS), central processing unit and the wireless communication module sequentially connected is set and forms computing circuit,
And formation bridge circuit that each strain film group and resistance R2, R3, R4 are sequentially end-to-end, each bridge circuit is connected with each computing circuit, and all computing circuits are all communicated with background data base and Surveillance center by cordless communication network.
Further, described strain film equivalent resistance is ri, resistance ri and resistance R2, R3, R4 are sequentially end-to-end formation bridge circuit, wherein the common connection end of resistance ri and resistance R2 is a end, the common connection end of resistance ri and resistance R3 is b end, the common connection end of resistance R3 and resistance R2 is c end, and the common connection end of resistance R2 and resistance R4 is d end, and b end is connected AC power U with d end
i, a end and c end are voltage output end U
oand be connected with dynamic strain indicator input end, dynamic strain indicator output terminal is connected with data acquisition system (DAS) input end, and data acquisition system (DAS) output terminal is connected with central processing unit.
Further, be also provided with power circuit, described power circuit input end connects AC power U
i, described power circuit exports direct supply and is respectively dynamic strain indicator, data acquisition system (DAS) and central processing unit and wireless communication module power supply.
The present invention is by adopting technique scheme, and compared with prior art, tool has the following advantages:
Earth mat test pipeline system based on strain film of the present invention, coordinating is sticked at the strain film of pipe surface, and design an equivalent electrical circuit, detect strain film to the change of circuitous resistance, thus detect the position of trouble spot, even if even if the most small loss is located exactly, for pipeline maintenance provides detection and location function the most timely.
A kind of earth mat test pipeline method based on strain film of the present invention, by the strain film that is sticked at pipe surface, and coordinate related circuit to respond to the crack on pipeline and miniature deformation, thus accurate targeted duct surface crack and miniature deformation, there is provided the maximized time to ensure to pipeline maintenance, and greatly reduce pipeline maintenance cost.
Accompanying drawing explanation
Fig. 1 is the structural representation of embodiments of the invention 1.
Fig. 2 is the A portion enlarged diagram of Fig. 1.
Fig. 3 is the circuit equivalent schematic diagram of embodiments of the invention 1.
Fig. 4 is the structural representation of embodiments of the invention 2.
Embodiment
Now the present invention is further described with embodiment by reference to the accompanying drawings.
As a specific embodiment, as shown in Figure 1 to Figure 3, a kind of earth mat test pipeline system based on strain film of the present invention, comprises the strain film be sticked in pipeline 1 appearance, and be arranged on the waterproofing membrane 3 of strain film appearance, described strain film is N number of ring-type strain film 2, and namely waterproofing membrane 3 can be set to N number of, is separately positioned on N number of ring-type strain film 2 surface, also one can be arranged, be coated on all ring-type strain films 2 surface, wherein N >=2, and N is positive integer.Each ring-type strain film 2 is close to and is located at pipeline circumferential hoop outer wall, between adjacent two ring-type strain films 2, there is dielectric film 4 to isolate, become strain film group B by wire 10 series connection between every n ring-type strain film 2, wherein 1≤n≤N, in the present embodiment, n gets 16.Strain film group and resistance R2, R3, R4 are sequentially end-to-end formation bridge circuit, and connect dynamic strain indicator, data acquisition system (DAS) and central processing unit successively, described wireless communication module and central processing unit are electrically connected, and wireless communication module is communicated with background data base and Surveillance center by cordless communication network.Described central processing unit 8 comprises dsp chip and auxiliary circuit thereof.
Shown in concrete reference diagram 3, described strain film equivalent resistance is ri, resistance ri and resistance R2, R3, R4 are sequentially end-to-end formation bridge circuit, wherein the common connection end of resistance ri and resistance R2 is a end, the common connection end of resistance ri and resistance R3 is b end, the common connection end of resistance R3 and resistance R2 is c end, and the common connection end of resistance R2 and resistance R4 is d end, and b end is connected AC power U with d end
i, a end and c end are voltage output end U
oand be connected with dynamic strain indicator input end, dynamic strain indicator output terminal is connected with data acquisition system (DAS) input end, and data acquisition system (DAS) output terminal is connected with central processing unit.
Also comprise power circuit 11, described power circuit input end connects AC power U
i, described power circuit output direct supply is respectively dynamic strain indicator 6, data acquisition system (DAS) 7 and central processing unit 8 and wireless communication module 9 is powered.
The equivalent resistance of strain film group B is ri, a part for this equivalent electrical circuit access bridge circuit, when there is fracture or miniature deformation in pipeline 1, there is miniature deformation or fracture etc. in corresponding ring-type strain film 2, the equivalent resistance ri of strain film group is changed, bridge circuit is by ri(i=1 ~ 3) the change in resistance amount of strain film group converts voltage variety to, voltage variety amplifies through dynamic strain indicator 6, filtering obtains signal original shape, signal original shape flows to data acquisition system (DAS) and carries out data storage, be sent to central processing unit 8, monitored by corresponding resistance, the equivalent resistance that then can obtain which strain film group B there occurs change, and result of calculation is sent to background data base and Surveillance center's communication by wireless communication module 9, conveniently overhaul location.
In the present embodiment, the structure of described strain film comprises silicon base, described silicon base is formed with raceway groove, described raceway groove is covered with a plurality of voltage dependent resistor (VDR), a plurality of voltage dependent resistor (VDR) is divided into two row's arrangements, and form Wheatstone bridge brachium pontis, described raceway groove seals by described a plurality of voltage dependent resistor (VDR), form vacuum channel, the part that described a plurality of voltage dependent resistor (VDR) corresponds to described vacuum channel is area of stress concentration, described silicon base is also formed with source region, drain region and drift region, described raceway groove is arranged between source region and drift region, and raceway groove and being isolated by protective seam between source region and drift region.
The Making programme of strain film is as follows:
A, form raceway groove on a silicon substrate, and cover a plurality of voltage dependent resistor (VDR) on this raceway groove,
B, a plurality of voltage dependent resistor (VDR) are divided into two row's arrangements, and form Wheatstone bridge brachium pontis,
Described raceway groove seals by C, described a plurality of voltage dependent resistor (VDR), forms vacuum channel,
The part that D, described a plurality of voltage dependent resistor (VDR) correspond to described vacuum channel is area of stress concentration,
F, form drain region on a silicon substrate,
G, on a silicon substrate raceway groove both sides formation source region and drift region, and raceway groove and protective seam is set between source region and drift region isolates.
Described strain film is of a size of width: 1-10cm, and the distance between adjacent two strain films is 10-20cm.
The present embodiment additionally provides a kind of earth mat test pipeline method based on strain film, comprises the following steps:
Evenly to be sticked N number of ring-type strain film in pipeline appearance, wherein N >=2, and to be sticked waterproofing membrane in each ring-type strain film appearance,
And dielectric film isolation is set between adjacent two ring-type strain films,
Strain film group is become by wired in series or parallel connection, wherein 1≤n≤N between every n ring-type strain film,
N dynamic strain indicator, data acquisition system (DAS), central processing unit and the wireless communication module sequentially connected is set and forms computing circuit,
And formation bridge circuit that each strain film group and resistance R2, R3, R4 are sequentially end-to-end, each bridge circuit is connected with each computing circuit, and all computing circuits are all communicated with background data base and Surveillance center by cordless communication network.
Described strain film equivalent resistance is ri, resistance ri and resistance R2, R3, R4 are sequentially end-to-end formation bridge circuit, wherein the common connection end of resistance ri and resistance R2 is a end, the common connection end of resistance ri and resistance R3 is b end, the common connection end of resistance R3 and resistance R2 is c end, the common connection end of resistance R2 and resistance R4 is d end, and b end is connected AC power U with d end
i, a end and c end are voltage output end U
oand be connected with dynamic strain indicator input end, dynamic strain indicator output terminal is connected with data acquisition system (DAS) input end, and data acquisition system (DAS) output terminal is connected with central processing unit.
Also be provided with power circuit 11, described power circuit 11 input end connects AC power U
i, described power circuit output direct supply is respectively dynamic strain indicator 6, data acquisition system (DAS) 7 and central processing unit 8 and wireless communication module 9 is powered.
The equivalent resistance of strain film group B is ri, a part for this equivalent electrical circuit access bridge circuit, when there is fracture or miniature deformation in pipeline 1, there is miniature deformation or fracture etc. in corresponding ring-type strain film 2, the equivalent resistance ri of strain film group is changed, bridge circuit is by ri(i=1 ~ 3) the change in resistance amount of strain film group converts voltage variety to, voltage variety amplifies through dynamic strain indicator 6, filtering obtains signal original shape, signal original shape flows to data acquisition system (DAS) and carries out data storage, be sent to central processing unit 8, monitored by corresponding resistance, the equivalent resistance that then can obtain which strain film group B there occurs change, and result of calculation is sent to background data base and Surveillance center's communication by wireless communication module 9, conveniently overhaul location.
In the present embodiment, the structure of described strain film comprises silicon base, described silicon base is formed with raceway groove, described raceway groove is covered with a plurality of voltage dependent resistor (VDR), a plurality of voltage dependent resistor (VDR) is divided into two row's arrangements, and form Wheatstone bridge brachium pontis, described raceway groove seals by described a plurality of voltage dependent resistor (VDR), form vacuum channel, the part that described a plurality of voltage dependent resistor (VDR) corresponds to described vacuum channel is area of stress concentration, described silicon base is also formed with source region, drain region and drift region, described raceway groove is arranged between source region and drift region, and raceway groove and being isolated by protective seam between source region and drift region.
The Making programme of strain film is as follows:
A, form raceway groove on a silicon substrate, and cover a plurality of voltage dependent resistor (VDR) on this raceway groove,
B, a plurality of voltage dependent resistor (VDR) are divided into two row's arrangements, and form Wheatstone bridge brachium pontis,
Described raceway groove seals by C, described a plurality of voltage dependent resistor (VDR), forms vacuum channel,
The part that D, described a plurality of voltage dependent resistor (VDR) correspond to described vacuum channel is area of stress concentration,
F, form drain region on a silicon substrate,
G, on a silicon substrate raceway groove both sides formation source region and drift region, and raceway groove and protective seam is set between source region and drift region isolates.
Described strain film is of a size of width: 1-10cm, and the distance between adjacent two strain films is 10-20cm.
Embodiment 2:
Shown in figure 4, the present embodiment is substantially the same manner as Example 1, and difference is to become strain film group B by wire 10 parallel connection between every n ring-type strain film 2.Its equivalent electrical circuit is also consistent with the equivalent electrical circuit of embodiment 1.The equivalent resistance of strain film group B is Ri, the b end of this equivalent electrical circuit access bridge circuit 5, when there is fracture or miniature deformation in pipeline 1, there is miniature deformation or fracture etc. in corresponding ring-type strain film 2, the equivalent resistance ri of strain film group is changed, bridge circuit is by ri(i=1 ~ 3) the change in resistance amount of strain film group converts voltage variety to, voltage variety amplifies through dynamic strain indicator 6, filtering obtains signal original shape, signal original shape flows to data acquisition system (DAS) and carries out data storage, be sent to central processing unit 8, monitored by corresponding resistance, the equivalent resistance that then can obtain which strain film group B there occurs change, and result of calculation is sent to background data base and Surveillance center's communication by wireless communication module 9, conveniently overhaul location.
Although specifically show in conjunction with preferred embodiment and describe the present invention; but those skilled in the art should be understood that; not departing from the spirit and scope of the present invention that appended claims limits; can make a variety of changes the present invention in the form and details, be protection scope of the present invention.
Claims (3)
1., based on an earth mat test pipeline method for strain film, it is characterized in that: comprise the following steps:
Evenly to be sticked N number of ring-type strain film in pipeline appearance, wherein N >=2, and to be sticked waterproofing membrane in each ring-type strain film appearance,
And dielectric film isolation is set between adjacent two ring-type strain films,
Strain film group is become by wired in series or parallel connection, wherein 1≤n≤N between every n ring-type strain film,
N dynamic strain indicator, data acquisition system (DAS), central processing unit and the wireless communication module sequentially connected is set and forms computing circuit,
And formation bridge circuit that each strain film group and resistance R2, R3, R4 are sequentially end-to-end, each bridge circuit is connected with each computing circuit, and all computing circuits are all communicated with background data base and Surveillance center by cordless communication network.
2. a kind of earth mat test pipeline method based on strain film according to claim 1, it is characterized in that: described strain film equivalent resistance is ri, resistance ri and resistance R2, R3, R4 are sequentially end-to-end formation bridge circuit, wherein the common connection end of resistance ri and resistance R2 is a end, the common connection end of resistance ri and resistance R3 is b end, the common connection end of resistance R3 and resistance R2 is c end, and the common connection end of resistance R2 and resistance R4 is d end, and b end is connected AC power U with d end
i, a end and c end are voltage output end U
oand be connected with dynamic strain indicator input end, dynamic strain indicator output terminal is connected with data acquisition system (DAS) input end, and data acquisition system (DAS) output terminal is connected with central processing unit.
3. a kind of earth mat test pipeline method based on strain film according to claim 2, is characterized in that: be also provided with power circuit, and described power circuit input end connects AC power U
i, described power circuit exports direct supply and is respectively dynamic strain indicator, data acquisition system (DAS) and central processing unit and wireless communication module power supply.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510154766.XA CN104713913A (en) | 2015-04-03 | 2015-04-03 | Underground pipeline testing method based on strain membranes |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510154766.XA CN104713913A (en) | 2015-04-03 | 2015-04-03 | Underground pipeline testing method based on strain membranes |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN104713913A true CN104713913A (en) | 2015-06-17 |
Family
ID=53413426
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201510154766.XA Pending CN104713913A (en) | 2015-04-03 | 2015-04-03 | Underground pipeline testing method based on strain membranes |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN104713913A (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0049501A2 (en) * | 1980-10-06 | 1982-04-14 | Siemens Aktiengesellschaft | Arrangement for measuring the pressure evolution inside cylindrical hollow objects |
| CN201561826U (en) * | 2009-10-30 | 2010-08-25 | 中国石油天然气股份有限公司 | High risk area pipeline body stress monitoring system based on meet an emergency |
| CN201615815U (en) * | 2010-02-08 | 2010-10-27 | 中国人民解放军军事交通学院 | Pressure non-disassembly detection device for hydraulic rubber oil tube |
| CN102788068A (en) * | 2011-05-18 | 2012-11-21 | 厦门市宏业工程建设技术有限公司 | Sticking method of strain gauge |
| US20130214771A1 (en) * | 2012-01-25 | 2013-08-22 | Radiation Monitoring Devices, Inc. | Systems and methods for inspecting structures including pipes and reinforced concrete |
| CN104214521A (en) * | 2014-08-27 | 2014-12-17 | 上海云逸能源系统有限公司 | Novel pipeline and fluid conveying pipeline for seabed |
| CN204042452U (en) * | 2014-05-07 | 2014-12-24 | 中联重科股份有限公司 | Pump truck conveying pipeline blockage monitoring equipment, alarm system and engineering machinery |
-
2015
- 2015-04-03 CN CN201510154766.XA patent/CN104713913A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0049501A2 (en) * | 1980-10-06 | 1982-04-14 | Siemens Aktiengesellschaft | Arrangement for measuring the pressure evolution inside cylindrical hollow objects |
| CN201561826U (en) * | 2009-10-30 | 2010-08-25 | 中国石油天然气股份有限公司 | High risk area pipeline body stress monitoring system based on meet an emergency |
| CN201615815U (en) * | 2010-02-08 | 2010-10-27 | 中国人民解放军军事交通学院 | Pressure non-disassembly detection device for hydraulic rubber oil tube |
| CN102788068A (en) * | 2011-05-18 | 2012-11-21 | 厦门市宏业工程建设技术有限公司 | Sticking method of strain gauge |
| US20130214771A1 (en) * | 2012-01-25 | 2013-08-22 | Radiation Monitoring Devices, Inc. | Systems and methods for inspecting structures including pipes and reinforced concrete |
| CN204042452U (en) * | 2014-05-07 | 2014-12-24 | 中联重科股份有限公司 | Pump truck conveying pipeline blockage monitoring equipment, alarm system and engineering machinery |
| CN104214521A (en) * | 2014-08-27 | 2014-12-17 | 上海云逸能源系统有限公司 | Novel pipeline and fluid conveying pipeline for seabed |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101216543B (en) | DC system earth fault detection and calibration method and its special equipment | |
| RU2632989C2 (en) | Method and device for determining location of single-phase-to-ground fault in distributing network based on wavelet transformation of transitional signals | |
| CN104713912A (en) | Underground pipeline testing system based on strain membranes | |
| US9874593B2 (en) | Decision support system for outage management and automated crew dispatch | |
| CN106199292A (en) | A kind of Portable precise conducting slip ring detecting system and detection method thereof | |
| CN104678257B (en) | A kind of pinpoint method of high voltage single-core cable protective layer failure | |
| CN102778631B (en) | Method for detecting and accurately positioning leakage of a sensing cable based on partial pressure compensation | |
| CN104052051A (en) | Direct current transmission and distribution system and method of operating the same | |
| CN103712071A (en) | Nuclear magnetic resonance petroleum transmission pipeline leakage hidden danger detecting instrument and detecting method | |
| CN104749484B (en) | Leakage monitoring device | |
| CN106033104A (en) | Low-temperature-environment high-voltage test device for 10-kV insulators | |
| CN106383259A (en) | Induced current and inducted voltage measurement method of multi-circuit transmission lines on same tower | |
| CN103389462B (en) | The switching synchronization of primary cut-out and separating brake synchronism detection method | |
| CN208059861U (en) | City integrated underground pipe gallery relative settlement monitoring system | |
| CN109490806A (en) | Detection method, system and device of sensor and readable storage medium | |
| CN111157178A (en) | System and method for monitoring seepage of avionic hub diaphragm wall based on BOTDA temperature technology | |
| CN88210103U (en) | Leakage detector for composite insulation pipeline | |
| CN104713913A (en) | Underground pipeline testing method based on strain membranes | |
| CN206074750U (en) | A kind of Power Transformer Faults detecting system | |
| CN205957301U (en) | Pipeline monitoring system | |
| CN101907657A (en) | Detection method for probe resistance | |
| CN102519625A (en) | Method for measuring temperature of porcelain insulators by aid of optical fiber Bragg grating temperature sensors | |
| CN104712911A (en) | Underground net pipeline test system based on big dipper positioning | |
| CN104712910A (en) | Underground net pipeline test method based on big dipper positioning | |
| CN104779249B (en) | The structure and preparation method of a kind of strain film |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20150617 |
|
| WD01 | Invention patent application deemed withdrawn after publication |