CN111673269A - Focal spot rapid movement regulation and control system based on surface type reflector set and regulation and control method thereof - Google Patents
Focal spot rapid movement regulation and control system based on surface type reflector set and regulation and control method thereof Download PDFInfo
- Publication number
- CN111673269A CN111673269A CN202010626584.9A CN202010626584A CN111673269A CN 111673269 A CN111673269 A CN 111673269A CN 202010626584 A CN202010626584 A CN 202010626584A CN 111673269 A CN111673269 A CN 111673269A
- Authority
- CN
- China
- Prior art keywords
- focal spot
- reflector
- function
- surface type
- wavefront
- 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.)
- Granted
Links
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
- B23K26/04—Automatically aligning, aiming or focusing the laser beam, e.g. using the back-scattered light
- B23K26/046—Automatically focusing the laser beam
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
- B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
- B23K26/064—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms
- B23K26/0643—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms comprising mirrors
Landscapes
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- Mechanical Engineering (AREA)
- Optical Elements Other Than Lenses (AREA)
Abstract
The invention discloses a focal spot fast moving regulation and control system based on a surface type reflector set. The frequency components of the fast moving focal spot which can be generated by the invention are not changed at different positions, and the moving speed of the focal spot has no internal relation with the pulse width of the laser. Therefore, the method has important application prospect in the field of strong fields such as interaction of high-power laser and substances.
Description
Technical Field
The invention relates to the technical field of laser focusing, in particular to a focal spot rapid movement regulating and controlling system based on a surface type reflector set and a regulating and controlling method thereof.
Background
The strong field physics is a new discipline developed in recent decades, mainly studies new physical phenomena generated in the interaction process of strong laser and substances, and is one of the most active leading research fields in the world at present. The generation of the strong laser field is a basic condition for carrying out strong field physical research, and the strong laser field benefits from a chirped pulse amplification technology and a large-caliber optical element focusing technology to realize the convergence of laser energy in time and space respectively.
At present, focal spots used in the strong field physical experiment in the prior art are all fixed in spatial position and do not change with time. With the continuous development of the science and technology, the dynamic motion characteristics of the focal spot are added, the focal spot with high peak power density capable of moving rapidly in a centimeter range is generated, a new degree of freedom is added for the strong field physical research, and the method has wide application prospects in the aspects of photon acceleration, laser plasma amplification, wake field acceleration, higher harmonic generation, novel X-ray sources and the like.
Fast moving focal spots (sliding or flying focus) are a relatively new concept that was independently proposed by the a.saint-Marie team in france and the Dustin h.froula team in the us in 2017 and 2018, respectively, and published in the Optica and Nature Photonics journal. The A.Saint-Marie team develops theoretical analysis and numerical simulation research of the focal spot with controllable moving speed, and proves that through properly adjusting chirp parameters, the super-light speed and sub-light speed movement of the focal spot can be realized, and the acceleration movement, the deceleration movement, the oscillation movement and the like of the focal spot can also be realized; froula's team developed a verification experiment study of the focal spot with controllable moving speed, and through the verification experiment, the focal spot moving speeds of-0.09 c (sub-beam speed) and 39c (super-beam speed) with the peak power tending to be constant (1 × 1018W/cm2) in the range of 4.5mm were obtained. As shown in fig. 1, the working principle of the prior art for generating a fast moving focal spot is: the chromatic aberration focusing system is adopted to focus the chirped laser pulse, different frequency components of the laser are converged at different spatial positions, and the same-direction (or reverse direction) and sub-light speed (or super-light speed) movement of a focusing light spot is realized by adjusting the laser pulse width, the chirp parameter and the like.
The core idea of the technology is as follows: (1) the chirp pulse technology is adopted to spatially separate the frequency components of the short laser pulse, and the moving speed of the focal spot is regulated and controlled by regulating the spatial separation degree (namely chirp parameters); (2) and focusing different frequency components on different focal lengths by adopting a chromatic aberration focusing system, and setting chirp parameters matched with the chromatic aberration focusing system to realize the macroscopic movement of the focal spot. The technology proposed for the first time realizes the fast movement of the high peak power density focal spot (light speed level), and causes no small fluctuation internationally, however, the technology has the following disadvantages: macroscopically, the focal spot has different frequency components (or wavelengths) at different positions in the moving process, and cannot be applied to some physical processes which are sensitive to laser wavelength; due to the spatial separation of frequency components, the peak power density of the focal spot generated by adopting the technology is one to three orders of magnitude weaker than that of the traditional focusing technology; the focal spot moving speed generated by the technology is in internal relation with the laser pulse width, and the focal spot moving at a specific speed under any pulse width condition cannot be realized.
Therefore, a focal spot fast moving regulation method and system based on a surface type reflector group, which have the advantages of simple structure, no chromatic aberration and high damage threshold, are urgently needed to be provided.
Disclosure of Invention
In view of the above problems, the present invention provides a focal spot fast moving control system based on a planar mirror set and a control method thereof, and the technical scheme adopted by the present invention is as follows:
the focal spot fast moving regulation and control system based on the surface type reflector group comprises a long focal depth reflector and a multi-step reflector which are arranged on the same central axis; the surface shapes of the long-focus deep reflecting mirror and the multi-step reflecting mirror and the moving speed of the focal spot satisfy the following relational expression:
wherein g (r) represents the wave front function of the laser, f (r) represents the curved function of the long-focus depth reflector, vf(r) represents the moving speed of the focal spot, r represents the radial coordinate; the above-mentioned
The surface type function of the multi-step reflector is as follows:
fm(r)＝gm(r)/2 (2)
wherein, gm(r) represents a stepped wavefront function;
said stepped wavefront function gmThe expression of (r) is:
gm(r)＝[g(r)/ΔH]·ΔH (3)
where Δ H represents a height difference between adjacent steps.
Preferably, the wave front height H of the multi-step reflector is provided with N steps; n is a natural number more than 8; the wavefront height H is calculated from a wavefront function g (R) obtained in formula (1) by H ═ g (0) -g (R), where R is the radius of the surface mirror; g (0) denotes the laser wavefront at the origin of the coordinates, and g (R) denotes the laser wavefront at the mirror radius R.
Preferably, the long focal depth reflector is one of a cone reflector, a logarithmic function reflector and a parabolic reflector with an aperture smaller than or equal to 0.2 mm.
A regulating method of a focal spot rapid movement regulating system based on a surface type reflector set is characterized in that a long-focus depth reflector and a multi-step reflector are adopted to carry out focal spot rapid movement regulation.
Compared with the prior art, the invention has the following beneficial effects:
(1) the invention skillfully arranges the long focal depth reflector and the multi-step reflector, and obtains focal spots with specific moving speeds such as super light speed, sub light speed or negative light speed in a focal depth area; in addition, the invention can generate fast moving focal spots, the frequency components of the focal spots are not changed at different positions in the focal depth area, and the moving speed of the focal spots has no internal relation with the laser pulse width;
(2) the invention adopts an aspheric reflector with the characteristic of uniform long focal depth, which mainly focuses the incident laser ring spot at different radius positions on different focal point space positions; in addition, the invention adopts a multi-step reflector with a surface type, which mainly forms a required mesa wave front structure. Because the reflector has the advantages of no color difference, high damage threshold and the like, the frequency components of the rapidly moving focal spot at different positions are unchanged, the moving speed of the focal spot is unrelated to the laser pulse width, and another feasible implementation way is provided for the generation of the rapidly moving focal spot.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention, and therefore should not be considered as limiting the scope of protection, and for those skilled in the art, other related drawings may be obtained from these drawings without inventive effort.
FIG. 1 is a schematic diagram of the focusing of different zones to different spatial positions in the focal depth region according to the present invention.
FIG. 2 is a schematic diagram of the operation of the multi-step mirror of the present invention to obtain a desired stepped wavefront.
FIG. 3 is a curve diagram of the logarithmic function mirror according to the present invention.
FIG. 4 is a test chart of the stepped wavefront function of the present invention.
FIG. 5 is a graph showing the test curves of the present invention in which the moving speed is 0.5c, 2c and-c.
Detailed Description
To further clarify the objects, technical solutions and advantages of the present application, the present invention will be further described with reference to the accompanying drawings and examples, and embodiments of the present invention include, but are not limited to, the following examples. All other embodiments that can be derived by a person skilled in the art from the embodiments given in the present application without making any creative effort fall within the protection scope of the present application.
Examples
As shown in fig. 1 to 5, the present embodiment provides a focal spot fast moving adjustment system based on a surface-type mirror group and an adjustment method thereof, which perform focal spot fast moving adjustment by using a long focal depth mirror and a multi-step mirror which are arranged in the same central axis. In the embodiment, by designing the surface type structures of the two reflectors, focal spots with specific moving speeds such as super light speed, sub light speed or negative light speed are obtained in the focal depth region. The design methods of two mirror surface type structures are as follows:
firstly, assume that the wave front function of the laser is g (r), the curved function of the long-focus depth reflector is f (r), and the moving speed of the focal spot is v (r)f(r) the following relationship exists between the two mirror surface types and the moving speed of the focal spot:
wherein r is a radial coordinate,
according to equation (1), at a given focal spot moving speed vf(r) and the long-focus depth reflector surface function f (r), the required wave front function g (r) can be obtained by calculation.
Second, a multi-step mirror surface structure f according to the wave front function g (r)m(r) the determination method is as follows:
(1) assuming that the wavefront height is H ═ g (0) -g (r), and the number of steps to be divided is N, the height difference between adjacent steps is Δ H ═ H/N; where g (0) represents the laser wavefront at the origin of the coordinates, and g (R) represents the laser wavefront at the mirror radius R.
(2) By the formula gm(r)＝[g(r)/ΔH]Δ H calculates a stepped wavefront function, where [ g (r)/Δ H]Represents the rounding of the function g (r)/Δ H; (3) final determinationThe surface type function of the multi-step mirror can be expressed as fm(r)＝gm(r)/2。
The working principle of this embodiment is shown in fig. 1 to fig. 2, and the laser with a specific spatial wave front is vertically incident on the long focal depth reflector to focus different zones to different spatial positions in the focal depth region, and the working principle is shown in fig. 1. For a specific focal spot moving speed, the required space wave front is calculated by a relational expression between the surface shapes of the long-focus depth reflector and the multi-step reflector and the moving speed of the focal spot. In the technical implementation layer, the required stepped wavefront is obtained by a multi-step mirror, and the schematic diagram of the working principle is shown in fig. 2.
In this embodiment, only the long-focus depth mirror is taken as a logarithmic function mirror for illustration, and other types of mirrors have the same principle, and are not described herein again. The specific parameters are as follows: the radius is 50mm, the central focal length is 510mm, and the focal depth range is 20 mm. At this time, the curved surface structure of the logarithmic function mirror is as shown in fig. 3. If the required focal spot movement speed in the depth of focus region is 0.5c, 2c and-c. The required wavefront function is calculated according to the relational expression between the surface types of the long-focus depth mirror and the multi-step mirror and the moving speed of the focal spot, and the stepped wavefront function can be given through the stepped calculation of this embodiment, and the result is shown in fig. 4.
In this embodiment, through time-scale diffraction theory numerical simulation calculation, the evolution rule of the focal spot in the focal depth region can be obtained under the three conditions that the focal spot moving speed is 0.5c, 2c, and-c, and the result is shown in fig. 5. In these numerical simulations, it was assumed that the time waveform of the incident laser light satisfies the gaussian function and the full width at half maximum was 6.66 ps. In fig. 5(a), it can be seen that one complete focal spot moves rapidly from left at a speed of 0.5 c. In fig. 5(b), the focal spot moves rapidly from left to right at a speed of 2c, but there is a large amount of fluctuation in the light intensity of the focal spot. Here, it is caused by the insufficient number of steps selected in this embodiment. In fig. 5(c), it is successfully achieved that the focal spot moves rapidly from right to left at the velocity-c, but there is also a large amount of fluctuation in the focal spot light intensity. It follows that the complete focal spot can be obtained in a further step by further increasing the number of steps of the wavefront structure, but when the size of the step ring is too small, diffraction effects occur, which cause a change in the transmission direction of the laser light and damage a portion of the laser energy. The present embodiment verifies through a large number of experiments that the number of steps N in the present embodiment is a natural number greater than 8, and the wavefront height H is calculated from the wavefront function g (r) obtained by the formula (1) by H ═ g (0) -g (r).
In summary, the invention adopts the long-focus deep reflector and the multi-step reflector to generate the fast moving focal spot, the frequency components of the focal spot at different positions are not changed, and the moving speed of the focal spot has no internal relation with the laser pulse width; compared with the prior art, the laser focusing device has outstanding substantive characteristics and remarkable progress, and has very high practical value and popularization value in the technical field of laser focusing.
The above-mentioned embodiments are only preferred embodiments of the present invention, and should not be construed as limiting the scope of the present invention, but all the modifications made by the principles of the present invention and the non-inventive efforts based thereon should fall within the scope of the present invention.
Claims (4)
1. The focal spot fast moving regulation and control system based on the surface type reflector group is characterized by comprising a long-focus deep reflector and a multi-step reflector which are arranged on the same central axis; the surface shapes of the long-focus deep reflecting mirror and the multi-step reflecting mirror and the moving speed of the focal spot satisfy the following relational expression:
wherein g (r) represents the wave front function of the laser, f (r) represents the curved function of the long-focus depth reflector, vf(r) represents the moving speed of the focal spot, r represents the radial coordinate; the above-mentioned
The surface type function of the multi-step reflector is as follows:
fm(r)＝gm(r)/2 (2)
wherein, gm(r) represents a stepped wavefront function;
said stepped wavefront function gmThe expression of (r) is:
gm(r)＝[g(r)/ΔH]·ΔH (3)
where Δ H represents a height difference between adjacent steps.
2. The focal spot fast moving and regulating system based on the surface type reflector set as claimed in claim 1, wherein the multi-step reflector has a wave front height H and is provided with N steps; n is a natural number more than 8; the wavefront height H is calculated from a wavefront function g (R) obtained in formula (1) by H ═ g (0) -g (R), where R is the radius of the surface mirror; g (0) denotes the laser wavefront at the origin of the coordinates, and g (R) denotes the laser wavefront at the mirror radius R.
3. The focal spot fast moving and adjusting system based on the surface type reflecting mirror set of claim 1, wherein the long focal depth reflecting mirror is one of a cone-shaped reflecting mirror, a logarithmic function reflecting mirror, and a parabolic reflecting mirror with an aperture of 0.2mm or less.
4. A regulating method of a focal spot rapid movement regulating system based on a surface type reflector set according to any one of claims 1 to 3 is characterized in that a long-focus depth reflector and a multi-step reflector are adopted for rapid focal spot movement regulation.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010626584.9A CN111673269B (en) | 2020-07-01 | 2020-07-01 | Focal spot rapid movement regulation and control system based on surface type reflector set and regulation and control method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010626584.9A CN111673269B (en) | 2020-07-01 | 2020-07-01 | Focal spot rapid movement regulation and control system based on surface type reflector set and regulation and control method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111673269A true CN111673269A (en) | 2020-09-18 |
| CN111673269B CN111673269B (en) | 2022-05-31 |
Family
ID=72437550
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010626584.9A Active CN111673269B (en) | 2020-07-01 | 2020-07-01 | Focal spot rapid movement regulation and control system based on surface type reflector set and regulation and control method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111673269B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114001820A (en) * | 2021-11-02 | 2022-02-01 | 中国工程物理研究院激光聚变研究中心 | Single shot measurement method and device for flight focal spot evolution process based on Tyndall effect |
Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU1834001A (en) * | 2000-02-08 | 2001-08-09 | Boeing Company, The | Focus control for search lights |
| CN101369044A (en) * | 2001-08-10 | 2009-02-18 | 佳能株式会社 | Zoom lens control apparatus |
| WO2011044361A1 (en) * | 2009-10-08 | 2011-04-14 | Pinebrook Imaging Systems Corporation | An optical imaging writer system |
| CN105537760A (en) * | 2016-01-12 | 2016-05-04 | 上海理工大学 | Controllable laser processing device based on wavefront modulation |
| CN108873322A (en) * | 2018-07-02 | 2018-11-23 | 中国工程物理研究院激光聚变研究中心 | A kind of Diode laser non-spherical reflector curved-surface structure determines method and system |
| CN109031682A (en) * | 2018-07-10 | 2018-12-18 | 北京润和微光科技有限公司 | The generation system and method for Diode laser, small spot based on diffraction optical element |
| CN109507792A (en) * | 2018-12-27 | 2019-03-22 | 湖南品信生物工程有限公司 | A kind of optical microscopy auto focusing method based on machine learning |
| CN109581558A (en) * | 2018-12-26 | 2019-04-05 | 中国科学院长春光学精密机械与物理研究所 | A kind of preparation method and multifocal diffractive element of multifocal diffractive element |
| WO2020027855A1 (en) * | 2018-08-02 | 2020-02-06 | Oculus Vr, Llc | Wearable display with coherent replication |
| CN110837215A (en) * | 2019-11-05 | 2020-02-25 | 中国科学院光电技术研究所 | High-efficiency laser direct-writing photoetching method capable of realizing long-focal-depth and small-focal-spot structure |
-
2020
- 2020-07-01 CN CN202010626584.9A patent/CN111673269B/en active Active
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU1834001A (en) * | 2000-02-08 | 2001-08-09 | Boeing Company, The | Focus control for search lights |
| CN101369044A (en) * | 2001-08-10 | 2009-02-18 | 佳能株式会社 | Zoom lens control apparatus |
| WO2011044361A1 (en) * | 2009-10-08 | 2011-04-14 | Pinebrook Imaging Systems Corporation | An optical imaging writer system |
| CN105537760A (en) * | 2016-01-12 | 2016-05-04 | 上海理工大学 | Controllable laser processing device based on wavefront modulation |
| CN108873322A (en) * | 2018-07-02 | 2018-11-23 | 中国工程物理研究院激光聚变研究中心 | A kind of Diode laser non-spherical reflector curved-surface structure determines method and system |
| CN109031682A (en) * | 2018-07-10 | 2018-12-18 | 北京润和微光科技有限公司 | The generation system and method for Diode laser, small spot based on diffraction optical element |
| WO2020027855A1 (en) * | 2018-08-02 | 2020-02-06 | Oculus Vr, Llc | Wearable display with coherent replication |
| CN109581558A (en) * | 2018-12-26 | 2019-04-05 | 中国科学院长春光学精密机械与物理研究所 | A kind of preparation method and multifocal diffractive element of multifocal diffractive element |
| CN109507792A (en) * | 2018-12-27 | 2019-03-22 | 湖南品信生物工程有限公司 | A kind of optical microscopy auto focusing method based on machine learning |
| CN110837215A (en) * | 2019-11-05 | 2020-02-25 | 中国科学院光电技术研究所 | High-efficiency laser direct-writing photoetching method capable of realizing long-focal-depth and small-focal-spot structure |
Non-Patent Citations (3)
| Title |
|---|
| 杨祖华: "《椭圆反射式波带片光线追迹算法》", 《光学学报》 * |
| 林勇等: "激光光束的整形技术", 《激光杂志》 * |
| 陈明等: "一种用于曲面快速测量的激光片光源的研究", 《中国机械工程》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114001820A (en) * | 2021-11-02 | 2022-02-01 | 中国工程物理研究院激光聚变研究中心 | Single shot measurement method and device for flight focal spot evolution process based on Tyndall effect |
| CN114001820B (en) * | 2021-11-02 | 2023-06-06 | 中国工程物理研究院激光聚变研究中心 | Single shot measurement method and device for flying focal spot evolution process based on Tyndall effect |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111673269B (en) | 2022-05-31 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101794962B (en) | Self-adaptive high-order transverse mode laser coherent synthesis device | |
| CN108919483A (en) | A kind of hollow beam preparation facilities based on free-form surface lens array | |
| CN108445641A (en) | A kind of tunable semiconductor laser optical optical tweezers system | |
| CN111673269B (en) | Focal spot rapid movement regulation and control system based on surface type reflector set and regulation and control method thereof | |
| CN110554510A (en) | Optical imaging system of transmission type diffraction optical element | |
| CN111965832A (en) | Variable-power laser beam shaping optical system | |
| CN216462460U (en) | Multi-light path structure for additive manufacturing equipment | |
| Shealy | History of beam shaping | |
| CN112987321B (en) | Method and device for generating high-power vortex laser | |
| Gill et al. | Relativistic and ponderomotive effects on evolution of laser beam in a non-uniform plasma channel | |
| CN204154997U (en) | A kind of laser homogenizing system | |
| CN109683327B (en) | Light beam focal spot shaping and dynamic control system and method based on plasma regulation | |
| CN114355616B (en) | Shape-preserving sharp edge flat top femtosecond laser shaping method and device for deep groove micromachining | |
| CN215729157U (en) | System for generating and regulating symmetrical dovetail light beams | |
| CN111474708B (en) | Design method of vortex array mask plate in abnormal annular connection | |
| CN110018565B (en) | Method and device for improving focusing capacity of ultrafast laser beam | |
| CN102819109A (en) | Optical system for generating bottle beam by LED (Light-Emitting Diode) light source | |
| CN105182543A (en) | Method for generating Pearcey beam cluster | |
| CN113866866A (en) | Fiber grating writing device and fiber grating writing method | |
| CN117192786A (en) | Method for generating self-focusing light beam with adjustable focusing times and focal length | |
| CN118169878A (en) | Method for generating multiple solid focuses by self-focusing light beam carrying vortex | |
| CN204269927U (en) | A kind of laser aid producing multiple focus | |
| CN221281339U (en) | Beam expander capable of improving quality of laser beam | |
| Trela-McDonald et al. | Laser-written freeform optics for in-and out-of-focus beam shaping | |
| CN115113390B (en) | Beam shaping method based on improved particle swarm optimization |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |