阅读说明：本技术 一种人工影响天气催化作业装置及其控制系统和控制方法 (Weather modification catalytic operation device and control system and control method thereof ) 是由 王天宝 郑郁正 杨雄 文斌 赵斌 魏华 陈昌明 韦巍 贺南 袁正国 姜小云 康 于 2020-07-20 设计创作，主要内容包括：本发明公开了一种人工影响天气催化作业装置及其控制系统和控制方法,属于人工影响天气安全作业技术领域；该作业装置包括在箭体内依次设置的降落伞仓、仪表仓、控制仓、电池仓、旋翼仓、催化剂播撒仓和发动机仓,及设置在箭体尾部的尾翼,控制仓内置控制电路、导航电路和安全发射电路,其中控制电路控制火箭点火、装置飞行以及催化剂播撒。本发明通过将旋翼无人机与火箭有机结合,改进设计了新型催化剂播撒作业装置,并且通过改进后的发射控制器进行作业装置安全发射；与现有技术相比,本发明提高了人工影响天气作业催化作业的准确性、有效性和安全性,实现了可重复使用,同时大大地降低了人工影响天气作业的成本。(The invention discloses a weather modification catalysis operation device and a control system and a control method thereof, belonging to the technical field of weather modification safety operation; the operation device comprises a parachute cabin, an instrument cabin, a control cabin, a battery cabin, a rotor cabin, a catalyst scattering cabin and an engine cabin which are sequentially arranged in an rocket body, and an empennage arranged at the tail part of the rocket body, wherein a control circuit, a navigation circuit and a safe launching circuit are arranged in the control cabin, and the control circuit controls rocket ignition, device flight and catalyst scattering. According to the invention, the rotor unmanned aerial vehicle and the rocket are organically combined, a novel catalyst scattering operation device is improved and designed, and the operation device is safely launched through the improved launch controller; compared with the prior art, the invention improves the accuracy, effectiveness and safety of the artificial weather modification operation catalytic operation, realizes the repeated use and greatly reduces the cost of the artificial weather modification operation.)

1. A weather modification catalysis operation device is characterized by comprising a parachute bin, an instrument bin, a control bin, a battery bin, a rotor bin, a catalyst scattering bin, an engine bin and a tail wing arranged at the tail part of an arrow body, wherein the parachute bin, the instrument bin, the control bin, the battery bin, the rotor bin, the catalyst scattering bin and the engine bin are sequentially arranged in the arrow body; the parachute cabin is used for opening a parachute in an emergency so as to safely descend the operation device to the ground; the instrument bin is used for detecting operation data by using a detection instrument; the control bin is used for controlling the operation of the operation device and controlling the catalyst to be spread according to the detected operation data; the battery bin is used for supplying power to a circuit in the operation device; the rotor cabin is used for performing flight movement of the operation device by utilizing the plurality of deployable rotors; the catalyst scattering bin is used for filling and scattering a catalyst; the engine bin is used for transmitting the operation device to a specified operation cloud layer height; the empennage is used for keeping the working device in a stable state during flying and supporting the whole working device during landing.

2. The weather modification catalytic working apparatus as claimed in claim 1, wherein a parachute and a parachute release control mechanism are built in the parachute bay, and the parachute release control mechanism is configured to open the parachute to safely land the working apparatus to the ground when the rotor is opened or the flight control circuit is failed.

3. The weather modification catalysis work device of claim 1, wherein a temperature detector, a cloud particle detector, a micro radar detector, and a high-speed optical and infrared camera are disposed in the instrument chamber, and are configured to detect a temperature suitable for work, a size of cloud particles in a cloud layer, and video information of the particles in the cloud layer.

4. The weather modification catalysis work device of claim 1, wherein the control cabin is internally provided with a communication circuit, a Beidou navigation circuit, an ADS-B broadcasting circuit, a flight control circuit and a scattering control circuit, and the communication circuit, the Beidou navigation circuit, the ADS-B broadcasting circuit, the flight control circuit and the scattering control circuit are respectively used for communication, navigation, ADS-B information broadcasting, flight control and catalyst scattering control according to detected work data.

5. The weather modification catalytic working apparatus as claimed in claim 1, wherein the rotor housing has a plurality of deployable rotors disposed therein for performing ascending, descending, hovering, forward flying, backward flying, and descending operations of the working apparatus according to a control command from the flight control circuit.

6. The weather modification catalytic operation apparatus as claimed in claim 1, wherein the catalyst scattering bin is provided with a replaceable catalyst and a catalyst scattering mechanism, the catalyst is replaced and filled at each operation, and the catalyst scattering mechanism is used for scattering the catalyst.

7. The weather modification catalytic working apparatus as claimed in claim 1, wherein the engine compartment is provided with an engine ignition controller, a rocket engine and a propellant grain, the propellant grain is used for providing a power source for the rocket engine, and the rocket engine is used for transmitting the working apparatus to a specified working cloud level according to a control command of the engine ignition controller.

8. A control system for an artificial weather modification catalytic working apparatus, comprising the artificial weather modification catalytic working apparatus according to any one of claims 1 to 7, a launch controller mounted on a launch rack, and a command center;

the transmitting controller is used for acquiring the unique code of the engine ignition controller and the unique code of the operating device, sending the codes and the longitude and latitude position data of the operating device to a command center for code verification and airspace application, acquiring a transmitting password from the command center after the code verification and the airspace application are finished, and sending the transmitting password to the engine ignition controller;

and the command center is used for inquiring the transmission password according to the codes, applying for an airspace according to the cloud layer position and the longitude and latitude position data of the operation device, and sending the transmission password to the transmission controller after the application is finished.

9. The control system of weather modification catalysis work device of claim 8, wherein the launch controller is embedded with a central control unit, a Beidou positioning device, a satellite communication device, a device communication circuit communicating with an ignition controller in the work device, a launch controller operator biometric identification device, an encryption/decryption module, and an Ethernet interface circuit.

10. A control method of a weather modification catalytic operation device is characterized by comprising the following steps:

s1, carrying out self-test after the weather modification catalytic operation device as claimed in any one of claims 1 to 7 is powered on, and connecting the weather modification catalytic operation device with a launch controller after the self-test is finished;

s2, the transmitting controller acquires the unique code of the engine ignition controller and the unique code of the operating device, and sends the codes and the longitude and latitude position data of the operating device to a command center;

s3, the command center inquires the transmission password according to the codes, applies for airspace according to the cloud layer position and the longitude and latitude position data of the operation device, and sends the transmission password to the transmission controller after the application is finished;

s4, the transmitting controller sends the transmitting password to the engine ignition controller, and the engine ignition controller carries out the transmitting password comparison and then carries out the ignition transmitting operation device;

s5, detecting temperature, height and speed data by the operation device in the transmitting process, and broadcasting longitude and latitude, height and speed information of the operation device;

s6, the operation device controls the rotor wing to be opened after the propellant grains are burnt, and flies to a cloud layer for catalytic operation to scatter the catalyst;

and S7, after the sowing is finished, the working device descends to a set height and flies to a launching place to land.

Technical Field

The invention relates to the technical field of artificial weather modification operation, in particular to an artificial weather modification catalysis operation device, a control system and a control method thereof.

Background

At present, the main means of artificially influencing weather is to use an antiaircraft gun and a rocket launcher to launch a catalytic bomb for catalysis on the ground, and use a manned aircraft to implement modes of silver iodide flare combustion and scattering and the like to artificially influence weather operation in the air.

The manner of launching a catalytic projectile or rocket projectile using an antiaircraft gun or rocket launcher has the following problems: the antiaircraft gun catalytic bomb uses a delay fuse, and can explode after the time is up to complete the scattering of the carried catalyst, but the temperature and the time for scattering are not necessarily optimal; the catalytic scattering time of the rocket projectile is fixed or the scattering time is fixed on site according to radar detection data, so that the rocket projectile does not accord with the actual situation of a cloud layer, and the rocket projectile is linearly scattered consistent with a trajectory after being launched, so that the rocket projectile cannot be scattered according to requirements and in a variable mode. The high fixed and all belong to disposable product of present antiaircraft gun catalysis shell and rocket catalysis shell shooting, use the completion after or explode out, or fall to ground through the umbrella, unable used repeatedly, shoot high also unable adjustment, lead to catalysis operation cost height, catalytic effect is unsatisfactory. The manned aircraft can be catalyzed according to the actual conditions of cloud layers, but the manned aircraft belongs to a fixed-wing aircraft, is inflexible, has very high operation cost and is suitable for large-area operation.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a weather modification catalysis operation device, a control system and a control method thereof.

In order to achieve the purpose of the invention, the invention adopts the technical scheme that:

a weather modification catalysis operation device comprises a parachute bin, an instrument bin, a control bin, a battery bin, a rotor bin, a catalyst spreading bin and an engine bin which are sequentially arranged in an arrow body, and a tail wing arranged at the tail part of the arrow body; the parachute cabin is used for opening a parachute in an emergency so as to safely descend the operation device to the ground; the instrument bin is used for detecting operation data by using a detection instrument; the control bin is used for controlling the operation of the operation device and controlling the catalyst to be spread according to the detected operation data; the battery bin is used for supplying power to a circuit in the operation device; the rotor cabin is used for performing flight movement of the operation device by utilizing the plurality of deployable rotors; the catalyst scattering bin is used for filling and scattering a catalyst; the engine bin is used for transmitting the operation device to a specified operation cloud layer height; the empennage is used for keeping the working device in a stable state during flying and supporting the whole working device during landing.

Furthermore, the parachute cabin is internally provided with a parachute and a parachute release control mechanism, and the parachute release control mechanism is used for opening the parachute to safely land the operation device to the ground when the rotor wing is opened and loses efficacy or the flight control circuit loses efficacy.

Furthermore, a temperature detecting instrument, a cloud particle detecting instrument, a micro radar detecting instrument and a high-speed optical and infrared camera are arranged in the instrument bin and used for detecting the temperature suitable for operation, the size of cloud particles in a cloud layer and the video information of the particles in the cloud layer.

Furthermore, a communication circuit, a Beidou navigation circuit, an ADS-B broadcasting circuit, a flight control circuit and a scattering control circuit are arranged in the control bin and are respectively used for communication, navigation, ADS-B information broadcasting, flight control and catalyst scattering control according to detected operation data.

Furthermore, a plurality of deployable rotor wings are arranged in the rotor cabin and are used for carrying out ascending, descending, hovering, forward flying, backward flying and landing operation actions of the operation device according to a control command of the flight control circuit.

Furthermore, a replaceable catalyst and a catalyst scattering mechanism are arranged in the catalyst scattering bin, the catalyst is replaced and filled during each operation, and the catalyst scattering mechanism is used for scattering the catalyst.

Further, an engine ignition controller, a rocket engine and a propellant grain are arranged in the engine bin, the propellant grain is used for providing a power source for the rocket engine, and the rocket engine is used for transmitting the operation device to the designated operation cloud layer height according to a control command of the engine ignition controller.

The invention also provides a control system of the artificial weather modification catalytic operation device, which comprises the artificial weather modification catalytic operation device, a launching controller arranged on the launching frame and a command center;

the transmitting controller is used for acquiring the unique code of the engine ignition controller and the unique code of the operating device, sending the codes and the longitude and latitude position data of the operating device to a command center for code verification and airspace application, acquiring a transmitting password from the command center after the code verification and the airspace application are finished, and sending the transmitting password to the engine ignition controller;

and the command center is used for inquiring the transmission password according to the codes, applying for an airspace according to the cloud layer position and the longitude and latitude position data of the operation device, and sending the transmission password to the transmission controller after the application is finished.

Furthermore, a central control unit, a Beidou positioning device, a satellite communication device, a device communication circuit communicated with an ignition controller in the operation device, a transmission controller operator biological characteristic identification device, an encryption and decryption module and an Ethernet interface circuit are arranged in the transmission controller.

The invention also provides a control method of the weather modification catalysis operation device, which comprises the following steps:

s1, the weather modification catalysis operation device is self-checked after being powered on, and is connected with a transmission controller after the self-check is completed;

s2, the transmitting controller acquires the unique code of the engine ignition controller and the unique code of the operating device, and sends the codes and the longitude and latitude position data of the operating device to a command center;

s3, the command center inquires the transmission password according to the codes, applies for airspace according to the cloud layer position and the longitude and latitude position data of the operation device, and sends the transmission password to the transmission controller after the application is finished;

s4, the transmitting controller sends the transmitting password to the engine ignition controller, and the engine ignition controller carries out the transmitting password comparison and then carries out the ignition transmitting operation device;

s5, detecting temperature, height and speed data by the operation device in the transmitting process, and broadcasting longitude and latitude, height and speed information of the operation device;

s6, the operation device controls the rotor wing to be opened after the propellant grains are burnt, and flies to a cloud layer for catalytic operation to scatter the catalyst;

and S7, after the sowing is finished, the working device descends to a set height and flies to a launching place to land.

The invention has the following beneficial effects:

the invention organically combines the rotor unmanned aerial vehicle and the rocket, improves and designs a novel catalyst spreading operation device, can be repeatedly used after refilling the catalyst and the solid propellant fuel, and carries out the launching of the operation device through the improved launching controller; compared with the prior art, the invention improves the accuracy, effectiveness and safety of the artificial weather modification operation catalytic operation, realizes the repeated use and greatly reduces the cost of the artificial weather modification operation.

Drawings

FIG. 1 is a schematic structural diagram of an artificial weather modification catalytic operation device of the present invention;

FIG. 2 is a schematic structural diagram of a control system of the weather modification catalytic operation device of the present invention;

FIG. 3 is a schematic flow chart of a control method of the weather modification catalytic operation device of the present invention.

Detailed Description

The following description of the embodiments of the present invention is provided to facilitate the understanding of the present invention by those skilled in the art, but it should be understood that the present invention is not limited to the scope of the embodiments, and it will be apparent to those skilled in the art that various changes may be made without departing from the spirit and scope of the invention as defined and defined in the appended claims, and all matters produced by the invention using the inventive concept are protected.

As shown in fig. 1, an embodiment of the present invention provides a weather modification catalytic operation device, which includes a parachute cabin, an instrument cabin, a control cabin, a battery cabin, a rotor cabin, a catalyst spreading cabin and an engine cabin, which are sequentially arranged in an arrow body, and a tail wing arranged at the tail of the arrow body; the parachute cabin is used for opening a parachute in an emergency so as to safely descend the operation device to the ground; the instrument bin is used for detecting operation data by using a detection instrument; the control bin is used for controlling the operation of the operation device and controlling the catalyst to be spread according to the detected operation data; the battery bin is used for supplying power to a circuit in the operation device; the rotor cabin is used for performing flight movement of the operation device by utilizing the plurality of deployable rotors; the catalyst scattering bin is used for filling and scattering a catalyst; the engine bin is used for transmitting the operation device to a specified operation cloud layer height; the empennage is used for keeping the working device in a stable state during flying and supporting the whole working device during landing.

The invention solves the problems of the prior antiaircraft gun, rocket catalytic bomb and airplane catalytic method, can be repeatedly used and realizes accurate low-cost catalytic operation according to requirements.

The parachute cabin is arranged at the top of the rocket body, a parachute and a parachute release control mechanism are arranged in the parachute cabin, and the parachute release control mechanism is used for opening the parachute to safely land the operation device to the ground in case of emergency. The emergency situation includes, but is not limited to, the safe landing of the working device by opening the parachute in case of rotor opening failure or flight control circuit failure.

The instrument bin is arranged behind the parachute bin, and is internally provided with a temperature detection instrument, a cloud particle detection instrument, a micro radar detection instrument, a high-speed optical camera, an infrared camera and other detection devices for protecting and storing the detection instruments and detecting the temperature, the size of cloud particles in a cloud layer, the video information of the particles in the cloud layer and other functions which are suitable for operation. According to the invention, the detecting and researching instrument is carried on the instrument bin, so that the condition in the cloud layer is detected in all directions, and a new way is provided for evaluating the effect of human-image operation and researching cloud physics.

The instrument bin wall is provided with high temperature resistant glass windows which respectively form an included angle of 90 degrees and are used for installing cameras. The instrument in the instrument cabin is connected with the control cabin control circuit through a high-speed bus or an Ethernet.

The control cabin is arranged behind the instrument cabin, and a communication module, a Beidou navigation module, an ADS-B broadcasting module, a flight control module and a scattering control module are arranged in the control cabin and are respectively used for performing communication, navigation, ADS-B information broadcasting, flight control, catalyst scattering control according to operation data detected by an instrument cabin detection instrument and other functions. The antenna used for navigation communication adopts a conformal antenna, and is conformal with the wall of the control cabin.

The battery compartment is arranged behind the control compartment, and the rechargeable battery is arranged in the battery compartment and used for supplying power to circuits in the whole operation device, such as a detection instrument in the instrument compartment, a functional module in the control compartment, a sowing control module, a rotor motor and the like.

The rotor wing bin is arranged behind the battery bin, is of an expandable and foldable structure, is internally provided with a plurality of expandable rotor wings, and is used for carrying out flight actions such as ascending, descending, hovering, forward flying, backward flying, descending and the like of the operation device according to a control command of the flight control module.

The catalyst scattering bin is arranged behind the rotor wing bin, a replaceable catalyst and a catalyst scattering mechanism are arranged in the catalyst scattering bin, the catalyst is replaced and filled during each operation, and the catalyst scattering mechanism is used for scattering the catalyst.

The engine bin is arranged behind the catalyst scattering bin, the engine ignition controller, the rocket engine and the propellant grain are arranged in the engine bin, the propellant grain is used for providing a power source for the rocket engine, and the rocket engine is used for transmitting the operation device to the specified operation cloud layer height according to the control instruction of the engine ignition controller.

The engine ignition controller comprises a central control unit or a microcontroller or a special chip, a communication circuit for realizing bidirectional communication, a storage circuit for storing a unique code of a module, a unique code of an operation device and a transmission code, a comparison circuit for comparing the transmission code and an ignition circuit for switching on an ignition direct current specific high-voltage waveform, and simultaneously, the engine ignition controller also measures whether the specific waveform meets the requirement of time width combination to prevent artificial generation; combinations of signals that do not meet the time width will not complete the ignition. An ignition passage in the engine ignition controller can be connected only when the unique code of the module and the transmission password acquired from the platform by the unique code of the cartridge case are compared and consistent with the local transmission password, so that a passage is provided for a specific ignition waveform.

The engine ignition controller is connected with the ignition control modules in the plurality of working devices through wires, safe voltage lower than 36V such as 9V is used for power supply, and bipolar differential coding is adopted to realize bidirectional encryption reliable communication.

The unique code comprises a manufacturer code, a production date, a production batch, a product code and a CRC (cyclic redundancy check) field; the factory code can be represented by 8 bits (which can represent 256 factories), the date of manufacture and the batch can be represented by 16 bits for the year, month and day, 8 bits for the batch, 4 bits for the product code, and 2 bits for the CRC field.

The tail wing is arranged behind the engine bin and is used for enabling the operation device to be in a stable state during flying and supporting the whole operation device during landing.

Based on the weather modification catalysis operation device, the invention also provides a control system of the weather modification catalysis operation device, which comprises the weather modification catalysis operation device, an emission controller arranged on an emission frame and a command center, wherein the emission controller is arranged on the emission frame;

the transmitting controller is used for acquiring the unique code of the engine ignition controller and the unique code of the operating device, sending the codes and the longitude and latitude position data of the operating device to a command center for code verification and airspace application, acquiring a transmitting password from the command center after the code verification and the airspace application are finished, and sending the transmitting password to the engine ignition controller;

and the command center is used for inquiring the transmission password according to the codes, carrying out airspace application according to the cloud layer position and the longitude and latitude position data of the operation device, and sending the transmission password to the transmission controller after the application is finished.

The transmitting controller is internally provided with a control CPU or MCU or a special chip, a Beidou positioning device, a mobile communication or satellite communication device, a communication circuit communicated with an ignition controller internally arranged in an operation device, a specific high-voltage waveform generating circuit for generating ignition of the operation device, a biological characteristic identification device of an operator of the transmitting controller, such as a human face, a fingerprint, a palm print and the like, an Ethernet interface and an encryption and decryption module.

Before transmission, the transmission controller needs to encrypt and report longitude and latitude information, launcher information, an ignition controller unique code of a transmitted operation device and an operation device unique code of the transmission controller to a management platform so as to obtain a transmission password; the longitude and latitude information of the launching controller is acquired by a built-in Beidou module, the information of a launcher is acquired by a biological characteristic acquisition device such as a camera or a fingerprint or palm print acquisition module, and the unique code of the built-in ignition controller of the operation device and the unique code of the operation device are acquired by a communication protocol between the launching controller and the built-in ignition controller of the operation device. As a preferred embodiment, the communication content can be encrypted and decrypted by using an AES algorithm or a hash algorithm.

The position represented by the longitude and latitude where the transmitting controller is located is reported to the platform and then belongs to a position where the transmitting is not allowed, and the transmitting controller cannot acquire a transmitting password; if the time period for the emission controller of the operation device to apply for emission is reported to the platform, the platform finds that the airspace where the emission controller is located does not allow emission or can not obtain an emission password; if the operator of the transmitter reported by the transmission controller of the operation device does not have the transmission qualification, the transmission controller can not obtain the transmission password, thereby ensuring the safety of the transmission activity.

The invention utilizes the cooperation of the emission controller and the engine ignition controller in the operation device to complete the ignition emission of the operation device, realizes the safe and controllable emission of the operation device and the real-time communication with the operation device through a satellite, and realizes the real-time communication of the data, the information and the video of the whole operation process of the operation device through the ground emission controller.

As shown in fig. 3, the present invention further provides a control method of the weather modification catalytic operation device, including the following steps S1 to S7:

s1, the weather modification catalysis operation device is self-checked after being powered on, and is connected with a transmission controller after the self-check is completed;

when the invention starts to launch the operation device, firstly, after receiving an operation preparation instruction of a command center by an operation point which artificially influences weather, a proper catalyst is added to the operation device according to the operation requirement, and an engine propellant grain is added according to the direction and height of a cloud layer.

And powering up the artificial weather-affecting catalytic operation device, carrying out self-inspection on detection, control, communication and navigation circuits of all parts by the operation device, sending self-inspection normal information to the transmission controller after all the inspection is normal, and carrying out communication connection with the transmission controller.

S2, the transmitting controller acquires the unique code of the engine ignition controller and the unique code of the operating device, and sends the codes and the longitude and latitude position data of the operating device to a command center;

s3, the command center inquires the emission password from the database according to the codes, and applies for an airspace according to the cloud layer position and the longitude and latitude position data of the operation device, and sends the emission password to the emission controller after the airspace application is finished;

the airspace application method comprises the steps of judging whether the position represented by the longitude and the latitude where the emission controller is located belongs to an emission-disallowed position, if so, refusing to issue the emission password to the emission controller, otherwise, judging whether the airspace where the emission time period applied by the emission controller is located does not allow emission, if so, refusing to issue the emission password to the emission controller, otherwise, judging whether an emitter operator reported by the emission controller does not have emission qualification, if so, refusing to issue the emission password to the emission controller, otherwise, the airspace application is completed, and accordingly, the safety of emission activities is guaranteed.

S4, the transmitting controller sends the transmitting password to the engine ignition controller, and the engine ignition controller carries out the transmitting password comparison and then carries out the ignition transmitting operation device;

s5, detecting temperature, height and speed data by the operation device in the transmitting process, and broadcasting longitude and latitude, height and speed information of the operation device;

after the operation device is transmitted, the detection instrument in the instrument bin is utilized to start to detect data such as temperature, height, speed and the like along the way, and longitude and latitude, height and speed information of the operation device is broadcasted through the ADS-B broadcasting module.

S6, the operation device controls the rotor wing to be opened after the propellant grains are burnt, and flies to a cloud layer for catalytic operation to scatter the catalyst;

the invention utilizes the flight control module to control the rotor wing to work and flies to a cloud layer (for example, a cloud layer at the temperature of-4 ℃) suitable for catalysis for catalyst spreading.

And S7, after the sowing is finished, the working device descends to a set height and flies to a launching place to land.

The invention utilizes the flight control module to control the rotor wing to descend to a proper height (such as 300 meters) and then fly to the launching site to descend.

Particularly, if the rotor wing fails to be opened, the parachute release control mechanism is started, the parachute is popped out to enable the operation device to land safely, and longitude and latitude information of the landing area is reported to be convenient to recover.

The operation device also supports cluster operation, realizes cooperative operation through the built-in Beidou navigation module, and quickly completes catalytic operation in a preset area.

It will be appreciated by those of ordinary skill in the art that the embodiments described herein are intended to assist the reader in understanding the principles of the invention and are to be construed as being without limitation to such specifically recited embodiments and examples. Those skilled in the art can make various other specific changes and combinations based on the teachings of the present invention without departing from the spirit of the invention, and these changes and combinations are within the scope of the invention.