138 results about "Particle transport" patented technology

Nanocrystals, compositions, and methods that aid particle transport in mucus are provided. In some embodiments, the compositions and methods involve making mucus-penetrating particles (MPP) without any polymeric carriers, or with minimal use of polymeric carriers. The compositions and methods may include, in some embodiments, modifying the surface coatings of particles formed of pharmaceutical agents that have a low water solubility. Such methods and compositions can be used to achieve efficient transport of particles of pharmaceutical agents though mucus barriers in the body for a wide spectrum of applications, including drug delivery, imaging, and diagnostic applications. In certain embodiments, a pharmaceutical composition including such particles is well-suited for administration routes involving the particles passing through a mucosal barrier.

Particles, compositions, and methods that aid particle transport in mucus are provided. The compositions and methods may include, in some embodiments, modifying the surface coatings of particles including pharmaceutical agents that have a low water/aqueous solubility. In some embodiments, a surface coating includes a synthetic polymer having pendant hydroxyl groups on the backbone of the polymer, such as poly(vinyl alcohol) (PVA). Such compositions and methods can be used to achieve efficient transport of particles of pharmaceutical agents though mucus barriers in the body for a wide spectrum of applications, including drug delivery, imaging, and diagnostic applications. In certain embodiments, a pharmaceutical composition including such particles is well-suited for administration routes involving the particles passing through a mucosal barrier.

Particles, compositions, and methods that aid particle transport in mucus are provided. The particles, compositions, and methods may be used, in some instances, for ophthalmic and/or other applications. In some embodiments, the compositions and methods may involve modifying the surface coatings of particles, such as particles of pharmaceutical agents that have a low aqueous solubility. Such compositions and methods can be used to achieve efficient transport of particles of pharmaceutical agents though mucus barriers in the body for a wide spectrum of applications, including drug delivery, imaging, and diagnostic applications. In certain embodiments, a pharmaceutical composition including such particles is well-suited for ophthalmic applications, and may be used for delivering pharmaceutical agents to the front of the eye and/or the back of the eye.

The invention discloses a method for establishing a measurement data-based simple and convenient irradiation source model of a medical linear accelerator. The method is characterized by comprising the following steps of: supposing that an irradiation source of the medical linear accelerator is on the part of the bottommost end of an MLC (Multi-leaf Collimator); measuring a flux pattern of data inversion from the accelerator through adjustment; and realizing simulation of the irradiation source of the medical linear accelerator by using a method of combining weight of outgoing particles and flux strength by combining the position of the outgaining particles with the flux distribution. Dose distribution in a template is obtained by using geometric description of a particle transport model of classic monte carlo program EGSnrc and a model of DOSXYZnrc. The method is established based on measurement data of the medical linear accelerator, so that the dependence of the conventional full accelerator simulation on the technical detail of the structure of the accelerator and heavy calculation task brought by need of sectional re-simulation in each modification process of the simulation parameter are avoided. The model can be used as an irradiation source model for an accurate monte carlo dosage calculation tool in a human body and can also be used for providing a source model for a dosage verification tool in a treatment planning system and an analytical dosage calculation tool of a treatment scheme optimization algorithm.

The invention discloses a ship reactor shielding design optimization method based on a neural network and a genetic algorithm. A Monte Carlo method is used for simulating and calculating the reactor neutron and photon transport process; an MCNP (Monte Carlo N Particle Transport Code) program is used for carrying out simulation and calculation on a ship reactor layered shielding model; a neutron and photon flux after the reactor shielding is obtained; the total equivalent dose is worked out; a topological structure of a BP (Back Propagation) neural network is determined according to the input parameter number n1 and the output parameter number n2 of a sample; an adaptation degree function of the genetic algorithm is determined according to a reactor shielding problem objective; the recommended adaptation degree function is selected; and the strong optimization capacity of the genetic algorithm is used and is mutually coupled with the neural network to find the optimum shielding parameter. The ship reactor shielding design optimization method has the advantages that the high fitting capability of the neural network is used; the time consumption of the MCNP program in the particle transport process is reduced; the good optimization capacity of the genetic algorithm is used; and the optimum shielding parameter can be found in few iteration steps.

The invention discloses a method of quick geometric processing for Monte-Carlo particle transport on basis of spatial grid partitioning and provides a cost function based spatial grid partitioning method on basis of the concept of spatial grid partitioning according to features of geometric processing of Monte-Carlo particle transport. According to the principle of minimum cost, a three-dimensional geometric model is subjected to spatial grid partitioning sequentially according to coordinate axes, geometries included in grids are determined when the cost is minimum, and a spatial grid model finally obtained is an optimal model. When the optimal model is applied to geometric processing of Monte-Carlo particle transport, spatial grid positioning can be performed fast according to particle spatial coordinates, the geometries included in the grids are traversed then, the number of candidate geometries to be searched for is greatly reduced, the geometries where particles locate can be determined fast, analog computation of Monte-Carlo particle transport is accelerated, and efficiency in geometric processing of Monte-Carlo particle transport is improved.

The invention provides a reverse Monte Carlo particle transporting and simulating system. According to a designed object or an external measuring result, and via direct reverse Monte Carlo simulating and particle transporting principle, three-dimensional transporting process and radioactive source information of radioactive intermediate particles are obtained. The reverse Monte Carlo particle transporting and simulating system comprises a state parameter and sequence inputting and processing module, an automatic modeling module, a reverse moving process simulating module, a result recording and error computing module, and a database managing module. Conventional Monte Carlo particle transporting and simulating are performed via a forward simulating method and belong to direct result simulating process according to direct reasons. In actual situation, in order to reproduce inputting or intermediate processes of the particle transportation, above information can be obtained via the reverse Monte Carlo particle transporting and simulating system. The reverse Monte Carlo particle transporting and simulating system has the advantage that intermediate and staring processes of three-dimensional particle transport is reversely simulated according to the target result, and precise simulating data for part designing, computing and optimizing of radiation dosage of a human body, breeding irradiating and the like about a nuclear device are provided.

The invention discloses a GPU-base (Graphics Processing Unit-based) multi-particle transport simulation method, which comprises the following steps that initiation is carried out; the thread number of a GPU is allocated according to the number of particles; the next collision points of the particles are computed in parallel by the GPU, whether the weight splitting or death of the particles takes place is judged, and events which are about to take place at the collision points are given; a computation result is returned to a CPU (central processing unit), and the CPU reallocates the thread number of the GPU according to the number and types of the events; the events are processed in parallel in the GPU, and the new energy, azimuths and other information of the particles and the information of produced secondary particles after the occurrence of the events are given and returned to the CPU; the CPU gathers the information and returns to the start of a program, and the steps are cycled until a simulation result of particle transport is statistically outputted. According to the embodiment of the invention, the GPU-base multi-particle transport simulation method can realize high-efficient experimental particle transport simulation, and while energy consumption is reduced, the efficiency of computation is increased.

The invention provides a medium deep charging potential and internal charging electric field acquisition method and a storage medium. The medium deep charging potential and internal charging electricfield acquisition method includes the steps: converting the orbit parameters into real-time coordinates in a geographic coordinate system by utilizing an MATLAB program according to the orbit parameters of each transfer section of the transfer orbit spacecraft, converting the real-time coordinates into real-time geomagnetic coordinates by utilizing a geomagnetic field mode IGRF, and substituting the real-time geomagnetic coordinates into a radiation band electronic environment model to obtain a real-time electronic environment energy spectrum; and taking the particle energy spectrum as an input condition, calculating the real-time particle deposition dose rate and the injection current density in the medium in particle transport simulation software Geant4, establishing a differential equation set to calculate the real-time electric field intensity and the charging potential in the medium, and identifying the deep discharge risk of the medium during satellite orbit transfer. According to the medium deep charging potential and internal charging electric field acquisition method, the medium deep charging potential and the internal charging electric field in the dynamic operation process of the transfer orbit spacecraft can be calculated, and the deep charging and discharging risk of the spacecraft when the spacecraft passes through the radiation band orbit and performs orbit transfer can be effectively evaluated.

A sliding contact arrangement comprises at least one slideway and, running thereon, at least one brush. Furthermore, a collecting vessel is provided through which the air flow caused by the movement of the slideway with respect to the brush flows. At the end of the cover, a collecting vessel for accommodating the particles transported by the air flow is provided. The collecting vessel can have a filter or else additional means for producing turbulence with the result that the air flow discharges the particles in the filter.

The invention discloses a device and a method for approximate simulation of particle transport and permeable pavement blockage under the runoff action. The device comprises a water channel, a support capable of adjusting slope of a permeable pavement model is arranged at the bottom of the water tank, the permeable pavement model is arranged in the water channel, devices used for reducing water flow state change to cause eddies and bubbles are arranged at the head and the tail of the permeable pavement level, and each device is composed of a straw array. A water tank I of a constant water head and a water tank II are arranged at the head and the tail of the water channel respectively, a particle collection device is arranged in the water tank II and disposed on an electronic balance, and a particle adding device is arranged in the upper stream of the permeable pavement. Influences on particle transport and hole blockage due to parameters such as inflow amount, infiltration flow, slope and sediment grain size are analyzed through an experiment and numerical simulation method. Research results provide a solid foundation for optimal permeable pavement design.

The invention discloses a variable stiffness soft robot system comprising a soft robot, a vacuum pumping device and a particle conveying device; the soft robot has a cavity surrounded by an elastic deformation cavity wall, and the elastic deformation cavity wall is provided with a vacuuming passage and a conveying passage; the vacuum pumping device is connected to the vacuuming passage for extracting the air inside the cavity to realize the vacuum or negative pressure inside the cavity; the particle transport device is connected to the transport channel to transport deforming medium of the soft robot into the cavity. The soft robot system of the invention retains the characteristics that the soft robot is easy to realize complex motion and has strong environmental adaptability. At the sametime, it can also enhance the rigidity of the robot in the static state, greatly enhance the carrying capacity of the robot, enhance the practicability of the soft robot, and expand the application range of the soft robot.

A process for increasing hydrogen recovery can include:

• • (a) sending a first gas from a hydrocarbon conversion zone at a first pressure to a hydrogen purification zone;
  • (b) combining a second gas from a particle transport vessel at a second pressure less than the first pressure with a tail gas from the hydrogen purification zone to create a combined stream; and
  • (c) recycling at least a portion of the combined stream to an inlet of the hydrogen purification zone.

The invention discloses a method for obtaining a proton single-particle effect cross section of a device. The method comprises a step of carrying out heavy ion single-particle effect experiment on thedevice to obtain heavy ion single-particle effect cross-section experimental data, a step of fitting the experimental data by using a Weibull function and obtaining a fitted heavy ion single-particleeffect cross-section function, a step of constructing a device structure including a plurality of metal wiring layers, calculating the nuclear reaction of protons with energy E and a material by using Monte Carlo particle transport simulation, generating secondary particle probability p(EP,L) with LET as L at a device silicon region, and further calculating an integral probability function P(EP,L), and a step of integrating a product of the heavy ion single-particle effect cross-section function and a proton integral probability function and calculating the proton single-particle effect crosssection of the device. According to the method, the evaluation of the ability of the device to resist the proton single particle can be achieved, and the method has the characteristics of clear physical concept and high accuracy of a data result.

The invention relates to a method, device and system for simulating particle transport and calculating body dosage in radiotherapy. The method for simulating particle transport includes the steps of recording the transport track of produced input particles; calculating the uncertainty of each lattice cell on the basis of the track of each batch of running particles, and determining that each lattice cell is a lattice cell reaching a standard when the uncertainty of the lattice cell does not exceed a first threshold value; obtaining the standard reaching rate of an area-of-interest, wherein the area-of-interest at least includes one lattice cell, and the standard reaching rate of the area-of-interest is the ratio of the standard reaching lattice cells in the area to all the lattice cells in the area; stopping continuing to input particles and outputting the transport track of the historical input particles if the standard reaching rate of the area-of-interest exceeds a second threshold value. The simulating efficiency of the particle transport process involved in the radiotherapy process can be improved.

The invention provides a simulation method and system for particle transport. The simulation method for particle transport comprises the following steps that a simulation object, an interest area, a beam restriction device and a source are arranged; source particles are generated by sampling, and information of the generated source particles comprises the weight, direction, position and type of the source particles and comprises one of the energy and the speed of the source particles; information of the source particles and secondary particles penetrating through the beam restriction device is acquired; the secondary particles are generated by performing sampling in the interest area, and the transport process of the source particles and the secondary particles is simulated; a transport result is output, wherein a super uniform random number sampling method is adopted as the method for generating the source particles by sampling and generating the secondary particles by sampling in the interest area, and the super uniform random number is a sequence obtained through the steps that an interval is equally divided to obtain multiple numbers and the order of the numbers is disrupted.

Particles, compositions, and methods that aid particle transport in mucus are provided. The particles, compositions, and methods may be used, in some instances, for ophthalmic and/or other applications. In some embodiments, the compositions and methods may involve modifying the surface coatings of particles, such as particles of pharmaceutical agents that have a low aqueous solubility. Such compositions and methods can be used to achieve efficient transport of particles of pharmaceutical agents though mucus barriers in the body for a wide spectrum of applications, including drug delivery, imaging, and diagnostic applications. In certain embodiments, a pharmaceutical composition including such particles is well-suited for ophthalmic applications, and may be used for delivering pharmaceutical agents to the front of the eye and/or the back of the eye.

The invention provides a space neutral atom imaging instrument calibration method. The method includes the following steps that: step 101, a particle transport calculation tool is adopted to calculate energy deposition values of different energy particles in a sensor, and corresponding relationships between particle energy and energy deposition are recorded; step 102, the corresponding relationships between the particle energy and the energy deposition are set according to the energy channel of an neutral atom imaging instrument, the energy deposition of the particles of neutral atoms of different energy in the sensor of the neutral atom imaging instrument is calculated, and the electron energy of the electrons of the neutral atoms is calculated according to the energy deposition which is obtained through calculation, and a plurality of energy-level energy points can be obtained; and step 103, an electronic detector and an instrument to be tested which are carried by a vacuum turntable in a vacuum tank measure electron beams sequentially, and therefore, comparison testing of various indicators of the instrument to be tested can be realized. With the space neutral atom imaging instrument calibration method and device provided by the invention adopted, calibration can be provided for instruments such as neutral atom detection instruments in energy, flux accuracy and resolution, and therefore, the quality of the research and development of the instruments can be ensured.

Particle collection, transport, and detection systems are disclosed. The systems are uniquely adapted for collecting or concentrating particles from a flowing medium and then transporting the collected particles to a desired location or for subsequent analysis. Electrostatic traveling wave grids can be used in conjunction with sample concentrators.

The invention provides a method for finely configuring the thickness of a shielding layer based on grid cutting. According to the method, a shielding layer model is subjected to right-angle grid cutting and the grid thickness is configured for achieving the purpose of finely configuring the thickness of the shielding layer. The method mainly comprises five steps for completing the fine configuration for the thickness of the shielding layer: (1) calculating the dosage field distribution on the inner side of the shielding layer by adopting a Monte Carlo particle transporting program and collecting the maximum value, minimum value and coordinate position of the dosage rate; (2) calculating the initial maximal thickness and minimal thickness of the shielding layer by adopting a half-value layer method; (3) confirming the increasing step length of the grid thickness by adopting a thickness/size adapting principle; (4) confirming the size step length of the grid along the coordinate direction by adopting a constant thickness step length method and calculating the grid cutting quantity; and (5) configuring the grid thickness according to the thickness step length and the grid position. The method provided by the invention is suitable for the occasions with limited volume of design space of the shielding layer and higher demand on the thickness space occupation of the shielding layer.