33results about How to "Low detectability" patented technology

The invention teaches a system and method for cooperatively networking digital chaos transmissions. The invention involves using generated digital chaos sequences as spreading sequences at a transmitside, receiving the spreaded signals at a receive side and despreading the signal, recovering signals at the receive side, and comparing a stored replica of the digital chaos spreading codes with thedigital chaos spreading codes used at the transmit side to, determine if the signals belong to predefined groups based on predetermined criteria, and forward the signals to a group member based on itsgroup member assignment.

The invention belongs to the technical field of application of fluorescent carbon nano materials and provides preparation of carbon quantum dots based on coal tar asphalt and a detection method for HCHO. The preparation method includes the steps of adding the coal tar asphalt to deionized water and performing ball milling and ultrasonic dispersion treatments to produce the carbon quantum dot dispersion liquid, wherein the mass ratio of the coal tar asphalt to hydrogen peroxide is 1:30-100; and performing H2O2 oxidization, high-speed centrifugation and vacuum drying to the carbon quantum dot dispersion liquid to produce carbon quantum dot powder. The method employs low-cost raw materials and is simple and green and pollution-free. The carbon quantum dots have good water solubility and have uniform particle size distribution, average size being about 3 nm. Selective detection on HCHO is achieved. The carbon quantum dots are low in detection limit on the HCHO, which is 0-50 [mu]M. Change between fluorescent intensity and concentration of HCHO has excellent linear relationship. The detection limit is lower than 1 ppb and high detection precision is achieved.

The invention relates to a foldable coaxial reverse propeller unmanned aerial vehicle and a striking method. The unmanned aerial vehicle comprises a data chain antenna, an upper rotor wing, an upper rotor wing propeller clamp, a driving module, a lower rotor wing propeller clamp, a lower rotor wing, a power and flight control module, an image load, a terminal-sensitive bullet, and a terminal-sensitive bullet sensor. The upper rotor wing and the lower rotor wing are connected with the driving module through the upper rotor wing propeller clamp and the lower rotor wing propeller clamp respectively, and the upper rotor wing and the lower rotor wing are driven to rotate under the driving of the driving module to produce lift force; the power and flight control module provides power for the driving module, and the data chain antenna is electrically connected to the power and flight control module to realize the data and instruction transmission between the power and flight control module and a ground control station; and the image load is installed on the outer side of the power and flight control module to be used for collecting an image of an attack target, and the terminal-sensitivebullet and the sensor used for sensitive attack targets are installed at the bottom of the unmanned aerial vehicle. According to the unmanned aerial vehicle and the striking method, the terminal-sensitive bullet is adopted for striking, so that the requirement of a flying platform on the bullet throwing precision is reduced, and low cost is realized.

The invention discloses a rotary vertical take-off and landing spray pipe based on a quasi-axisymmetric throat offset type pneumatic vectoring spray pipe and a design method of the rotary vertical take-off and landing spray pipe. The rotary vertical take-off and landing spray pipe comprises a fixed cylinder section, a first rotary cylinder section and a second rotary cylinder section. The front end of the first rotary cylinder section can be rotationally connected relative to the tail portion of the fixed cylinder section, and is connected with the actuating end of a first rotary driving mechanism. The front end of the second rotary cylinder section can be rotationally connected relative to the tail portion of the first rotary cylinder section, and is connected with the actuating end of asecond rotary driving mechanism. In a level flight mode, an inner flow channel of the spray pipe is of a typical double-throat structure of the quasi-axisymmetric throat offset type pneumatic vectoring spray pipe, and active and passive pneumatic disturbance or mechanical disturbance is carried out near a first throat. In a vertical take-off and landing mode, through rotation of the first rotary cylinder section and the second rotary cylinder section, an outlet of the spray pipe is made to incline downwards, and under the application of disturbance near the first throat, airflow at the outletof the spray pipe is steered by 90 degrees or above.

The invention belongs to the technical field of application of fluorescent carbon nano materials and provides preparation of carbon quantum dots based on coal tar asphalt and a detection method for HCHO. The preparation method includes the steps of adding the coal tar asphalt to deionized water and performing ball milling and ultrasonic dispersion treatments to produce the carbon quantum dot dispersion liquid, wherein the mass ratio of the coal tar asphalt to hydrogen peroxide is 1:30-100; and performing H2O2 oxidization, high-speed centrifugation and vacuum drying to the carbon quantum dot dispersion liquid to produce carbon quantum dot powder. The method employs low-cost raw materials and is simple and green and pollution-free. The carbon quantum dots have good water solubility and have uniform particle size distribution, average size being about 3 nm. Selective detection on HCHO is achieved. The carbon quantum dots are low in detection limit on the HCHO, which is 0-50 [mu]M. Change between fluorescent intensity and concentration of HCHO has excellent linear relationship. The detection limit is lower than 1 ppb and high detection precision is achieved.

The invention discloses a magnetic-based metal-organic nano core-shell material with adjustable diameter and a preparation method thereof. The method first adds 4,4'-bipyridine to AgNO 3 In the solution, after stirring evenly, add 1,2,3-benzenetricarboxylic acid, add KOH to adjust the pH, and react at 140°C to 170°C to obtain Ag-based metal-organic nanotube materials, and then surface silane-modified Fe 3 o 4 Add Ag-based metal-organic nanotube material into water, ultrasonically disperse evenly, add 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride and 4-dimethylaminopyridine to prepare Magnetic-based metal-organic nano core-shell materials. The invention regulates the diameter and specific surface area of ​​the material by adjusting the pH, and the maximum specific surface area can reach 177.42m 2 / g, significantly increase the contact area between the adsorbent and trihalomethane pollutants, effectively improve the adsorption effect, the adsorption removal efficiency can reach more than 90%, and the adsorbent can be recycled.

The invention discloses a mechanical-pneumatic composite vectoring nozzle with short-distance / vertical take-off and landing functions, which includes an aerodynamic steering section and a mechanical steering section; Nozzle and transition section; mechanical steering section includes cylinder A, cylinder B, bearing A, bearing B; along the fluid flow direction, cylinder A, bearing A, cylinder B, bearing B, transition section, axisymmetric / quasi The inlets of the axisymmetric throat offset aerodynamic vectoring nozzles are sequentially connected. Through the relative rotation of the two bearing mechanisms and the aerodynamic steering of the throat offset pneumatic vectoring nozzle, the function of airflow deflection exceeding 90° is realized without the mechanical structure deflecting by 90°, and the pneumatic vectoring nozzle can be used in the suspension Attitude control is carried out in the stopped state, which assists the continuous change of key parameters such as lift, thrust and vector angle of the entire exhaust system. It has many characteristics such as simple structure and relatively few motion mechanisms.