33 results about "Conditional stability" patented technology

The invention discloses an annular lower floating body semi-submersible platform. The annular lower floating body semi-submersible platform is provided with a lower floating body (1) and an upper ship body (2) which are connected through stand columns (3), wherein the lower floating body (1) is a regular hexagonal annular column body; the stand columns (3) are pentagonal column bodies and are uniformly distributed on the six corners of the lower floating body (1); the upper ship body (2) is a hexagonal frustum with a flare; and a moon pool (9) is arranged in the center of a box-type deck (8) of the upper ship body (2). The annular lower floating body semi-submersible platform is excellent in motion performance, has the characteristic of unconditional stability, is wide in application range of operation water depth, good in overall structure strength, light in weight, low in manufacturing cost and low in operation energy consumption, and can be applied to deepwater oil and gas exploitation under harsh marine environment conditions.

The invention relates to a method for determining a melting behavior and a melting point of a slag-like material, belonging to the technical field of detection of metallurgical slag-like material. The process comprises slag sample preparation, slag sample formation, high-temperature laser sample filling, experimental parameter setting, melting process observation and data and image processing. The method provided by the invention has the advantages that the defect of low accuracy of the slag column deformation method, i.e. the hemisphere point temperature testing method, in the traditional melting point testing can be overcome, and the limitations of difficulties in control of the stability of testing conditions and high testing costs in the method of slag melting in liquid steel can be eliminated. The initial melting temperature of the slag sample from the solid phase to the liquid phase and the melting temperature of the slag sample to the full liquid phase can be captured promptly so as to accurately determine the melting point of the slag sample; and the liquid phase nucleation, growth and other melting changes and behaviors of the slag sample in the heating process can also be analyzed, the direct theoretical basis and technical support can be provided for the curing of liquid slag and the control of metallurgical reaction in the steel-making and iron-making process, and different characteristics of different slag samples in the melting process can be used as an important means for evaluation of high-temperature properties of different slag samples.

A voltage regulator for digital loads combines a closed loop regulation circuit with an open loop topology. A transistor and a bank of transistors share the same voltage source VDD and gate control current. Each of the bank of transistors is sized to match different current load requirements and one or more may be switched in or out as appropriate when the digital load transitions from one operating mode to another. The regulator has good DC load regulation and unconditional stability regardless of output capacitance.

The invention provides an implementation algorithm for truncating a one dimensional Debye medium Crank-Nicolson perfectly matched layer, belongs to the technical field of numerical simulation, and aims to truncate a Debye dispersive medium by using the perfectly matched layer and simulate a limited memory space of a computer into an infinite space to simulate the propagation characteristic of electromagnetic wave in the Debye dispersive medium. The algorithm is characterized by comprising the following steps: a plurality of stretch coordinate variables are converted from a frequency domain to a z domain by using a bilinear transformation method, then a maxwell equation is dispersed in the time domain by using a Crank-Nicolson finite difference time domain method, an explicit iterative equation of an electric field is induced, and finally a value of an electromagnetic field component is solved. The algorithm has the advantages of unconditional stability and capabilities of improving the electromagnetic field calculation speed and saving memory.

The present invention discloses one kind of heating equipment for cigarette producing cylinder and similar unit and its control method. The heating equipment includes a cylinder, a hot blast filtering screen, a hot blast circulating blower, a temperature detecting unit, a steam jetting pipe, a steam regulating valve, a heat exchanger with frequency variator, and a programmable logic controller, as well as a humidity detecting unit, a wind rate detecting unit and a heat exchanger regulating valve. It has one first control loop formed with the programmable logic controller, the hot blast circulating blower and its frequency variator; one second control loop formed with the programmable logic controller, the humidity detecting unit and the steam regulating valve; and one third control loop formed with the programmable logic controller, the temperature detecting unit and heat exchanger regulating valve. The equipment is controlled through on-line detection, automatic control, feedback and cycling.

An integrative deep draft floating production platform with unconditional stability and an offshore installation method thereof are disclosed. The platform comprises an ring ballast tank (1) at the bottom, some columns with small cross sections (2), an ring buoyancy tank (3) at the middle part, some columns with large cross sections (4), and an upper drilling rig and oil gas processing module (5). The ballast tank adopts a permanently fixed ballast, and the tank is internally filled with weights to ensure that the center of buoyancy of the platform is higher than the center of gravity. The columns with large and small cross sections are uniformly arranged on the buoyancy tank and the ballast tank respectively, and the lower parts thereof are respectively integrated with the buoyancy tank and the ballast tank. Each column with a large cross section is provided with a central pore canal (7) axially, a lower part in the central pore canal is provided with a chopping board connection structure (8) with a groove. After the construction is completed, the columns with small cross sections are inserted into and pass through the central pore canals of the columns with large cross sections correspondingly, and the platform is in a folded state. Each column with a large cross section is provided with a group of mooring lines (15). The drilling rig and oil gas processing module is installed in the construction site, and the platform is transported to the installation site by a dry tow or wet tow as a whole and then is installed. The platform can be applied to deepwater oil and gas exploitation under harsh marine environment.

The invention discloses a fiber reinforced polyvinyl chloride composite floor and a production process thereof, belonging to the technical field of new materials. Through the use of carbon fiber, basalt fiber and glass fiber as additives, the three-layer fiber reinforced polyvinyl chloride composite floor is formed by using co-extrusion process. The upper and lower surface layers are made of fiber reinforced polyvinyl chloride, and the middle layer is polyvinyl chloride flooring. Using of fiber thermal stability and scientific formula, fiber reinforced polyvinyl chloride composite floor is lighter than the stone floor, and compared with ordinary PVC plastic flooring, the fiber reinforced polyvinyl chloride composite floor does not deform after sunlight irradiation for a long time and stability is good at average temperature. Fiber reinforced polyvinyl chloride composite floor is the ideal substitute for wood and machinable wood skin compound high-grade new floor is the most popular product in international market. The application technical problem of plastic flooring is solved by fiber modification, so that the technology application performance and the product technology content are improved and additional value is added.

The invention relates to a piecewise linear cyclic convolution-based one-dimensional left-handed material Crank-Nicolson perfectly matched layer realizing algorithm, belongs to the technical field of numerical simulation, and aims at shortening the left-handed material FDTD computational domain and simulating the finite memory spaces of computers into infinite spaces. The algorithm is technically characterized by comprising the following steps: in the process of transforming plural stretching coordinate variables from a frequency domain to a time domain, eliminating the second-order differential in the stretching variables by utilizing a piecewise linear cyclic convolution method so as to remarkably decrease the number of imported auxiliary variables and optimize the memory; dispersing a time domain Maxwell equation by utilizing a Crank-Nicolson time domain finite difference method so as to derive an explicit iterative equation of an electric field; and finally solving the value of an electromagnetic field component. The algorithm has the advantages of providing unconditional stability, improving the electromagnetic field calculation speed and saving the memory.

A broadband power amplifier using a novel high power feedback structure is disclosed in this patent. Feedback is widely used in amplifier design to broaden the bandwidth of the amplifier. Traditionally, the feedback resistor is either an axial resistor placed over the top of the transistor or a surface mount resistor with a long PCB trace making up the rest of the feedback path. However, each of these methods has it's limitations. The axial resistor doesn't have good heat sinking capability and therefore cannot handle high power. The feedback on PCB makes the feedback path long and becomes positive feedback at high frequency, thus limiting the high end frequency of operation of the amplifier in a stable region. The feedback structure disclosed in this patent has a good heat sinking path, has very short feedback path; allowing for higher frequency operation. We successfully applied the feedback structures to a Gallium Nitride (GaN) transistor, which is a new type of power transistor that has low parasitic capacitance and high optimum load impedance, and demonstrated an amplifier with very high output power over extraordinarily broad bandwidth. Matching networks have been optimized to improve performance and stability. We have demonstrated that unconditional stability is achievable while operating over a broad bandwidth using this feedback structure.

The invention discloses a semi-submersible platform with a horizontally downward floating body. The semi-submersible platform comprises a downward floating body, vertical columns 3 and an upper hull 4, wherein the vertical columns 3 are supported on the downward floating body, and the upper hull 4 is supported on the vertical columns 3. The downward floating body comprises the horizontally downward floating body 1 and a vertically downward floating body 2, the floating bodies are of a rectangular box type and are structurally vertically and horizontally crisscross and integrally symmetric, and the vertical columns 3 are arranged at vertically and horizontally crisscross points and are symmetrically arranged on the whole platform. The platform is excellent in movement performance, has unconditional stability, is adaptable to wide operating water depth range, fine in overall structural strength and low in operating energy consumption, and can be applied to production and living material storage and transfer and material supply for short and open seas and island construction and development under coastal environment conditions.

Methods and computer readable media for performing a compositional reservoir simulation of a subterranean hydrocarbon-bearing reservoir is provided. Reduced variables for flash computations are utilized with a methodology of conditional stability testing for achieving optimal efficiency of phase behavior computations in a compositional reservoir simulator. A least abundant phase is selected as primary variables for a primary phase and a secondary phase is selected for a more abundant phase to ensure stability by not dividing by a value near zero due to the selection of the primary phase as being associated with phase which is the least abundant. A bounded interval may be used to limit solution changes in reduced variable algorithms to achieve greater stability of algorithms. Stability tests may be performed during flash computations using reduced variables by employing a direct residual form based on the definition of the reduced variables and the tangent-plane distance condition.

The present invention relates to hair care compositions comprising an oxidizing agent and chelants having ratio calculated at pH 10 of at least 3.20 wherein log KCuL is the common logarithm of the Conditional Stability Constant of said chelant with Cu<2+> and log KCaL is the common logarithm of the Conditional Stability Constant of said chelant with Ca<2+>. Suitable chelants are diamine-N,N'-dipolyacids or monoamine monoamide-N,N'-dipolyacids. The compositions according to the present invention contribute to reducing the oxidative damage sustained by a keratinous fiber such as hair during bleaching, dyeing, perming or other oxidative treatments. Especially preferred diamine dipolyacid is ethylenediamine-N,N'-disuccinic acid (EDDS).

The invention relates to a two-dimensional dispersive medium Crank-Nicolson complete matching layer implementation algorithm based on a DG algorithm and belongs to the technical field of numerical simulation.The method aims at reducing a two-dimensional dispersive medium FDTD computational domain and simulating limited memory space of a computer into infinite space.The implementation algorithm is technically characterized in that in the process that a two-dimensional modified Maxwell equation with plural stretching coordinate variables is converted into the time domain finite difference from the frequency domain, an auxiliary differential equation method is utilized, and based on the Douglas-Gunn (DG) algorithm, an iteration equation with coefficients being block tridiagonal matrixes is approximately decomposed into two iteration equations with coefficients being tridiagonal matrixes, wherein the two iteration equations can be efficiently solved, and therefore computational efficiency is obviously improved.The implementation algorithm has the advantages of achieving unconditional stability, increasing the electromagnetic field computational speed and saving memory.

The invention relates to a one-dimension left-handed material Crank-Nicolson perfectly matched layer realizing algorithm based on an auxiliary differential equation, and belongs to the technical field of numerical simulation. The method aims at reducing the left-handed material FDTD (Finite-Different Time-Domain) computational domain, and simulating a computer finite memory space into an infinite space. The one-dimension left-handed material Crank-Nicolson perfectly matched layer realizing algorithm has the technical characteristics that in a process of converting a plurality of stretched coordinate variables from the frequency domain to the time domain, the second-order differential in the stretched variables is eliminated by an improved auxiliary differential equation method, so that the number of the introduced auxiliary variables is obviously lowered, and a memory is optimized; then, a time domain Maxwell equation is subjected to discretization by a Crank-Nicolson time domain finite differential method; an explicit iteration equation of an electric field is deduced out; and finally, a value of an electromagnetic field component is obtained. The one-dimension left-handed material Crank-Nicolson perfectly matched layer realizing algorithm has the advantages that the unconditional stability is realized; the electromagnetic calculation is accelerated; and the memory is saved.

The invention relates to the improvement on a lens manufacturing process. A manufacturing method of a polarized lens comprises the following steps of: A. cutting: selecting a polarized membrane and cutting the polarized membrane into a membrane size for producing the lens; B. coating: uniformly coating a bonding agent on one surface of the polarized membrane with the cut size; C. bending the membrane: carrying out extending and stretching on the polarized membrane coated with the bonding agent to meet the surface curvature of a lower mould of a mould; D. injecting glue: placing and fixing the bent membrane on the surface of the lower mould; and after an upper mould and the lower mould are combined, ejecting fused liquid from a cavity, wherein the temperature of the fused liquid is 220-260 DEG C; E. de-molding: after cooling, taking out a molded polarized lens semi-finished-product from the mould; and F. hardening: carrying out surface hardening treatment on the polarized lens semi-finished-product. The polarized lens structurally comprises a polarized membrane layer, a glue layer and a lens layer which are overlapped in sequence. The manufacturing method of the polarized lens, disclosed by the invention, can manufacture the polarized lens with excellent optical condition stability and an excellent lens inner stress function.

The invention relates to a two-dimensional vacuum Crank-Nicolson complete matching layer implementation algorithm based on an auxiliary differential equation and belongs to the technical field of numerical simulation.The method aims at reducing a vacuum FDTD computational domain and simulating limited memory space of a computer into infinite space.The implementation algorithm is technically characterized in that in the process that a two-dimensional modified Maxwell equation with plural stretching coordinate variables is converted into the time domain finite difference from the frequency domain, a Douglas-Gunn (DG) algorithm is utilized, an iteration equation with coefficients being block tridiagonal matrixes is approximately decomposed into two iteration equations with coefficients being tridiagonal matrixes, wherein the two iteration equations can be efficiently solved, and computational efficiency is obviously improved.The implementation algorithm has the advantages of achieving unconditional stability, increasing the electromagnetic field computational speed and saving memory.

The present invention discloses a domain decomposition parallel method effective for an unconditional stable time-domain finite difference method. In the present invention, the causal domain decomposition method is used to realize the height parallelization of the frog jump alternating direction implicit scheme time-domain finite difference method, and height parallel calculation can be carried out while the unconditional stability is maintained. According to the method disclosed by the present invention, the simulating calculation time on the time-domain finite difference method can be effectively saved, and the programming is simple and the method has a strong practical engineering application value.

The invention relates to an algorithm for realizing a perfectly matched layer by truncating plasmas based on a CNDG algorithm, and belongs to the technical field of numerical simulation. The algorithm is technically characterized in that a complex frequency offset stretch coordinate variable is substituted into a two-dimensional corrected Maxwell equation set, and an auxiliary differential equation method is used. In a process of deriving a relationship between dielectric flux density D and an electric field E, a piecewise linear recursive convolution method is applied. By applying a CNDG method, the electric field is solved by solving a three-diagonal equation, so that the calculation efficiency is improved and the time is saved. The algorithm has the advantages of unconditional stability and increased electromagnetic field calculation speed.

The invention relates to a two-dimensional Debye medium and Lorentz medium truncation Crank-Nicolson perfectly matched layer implementation algorithm, and belongs to the technical field of numerical simulation.The method aims at reducing a two-dimensional dispersive medium FDTD calculation domain and simulating limited memory space of a computer into infinite space.The method is technically characterized in that in the process of transforming a two-dimensional corrected Maxwell equation with multiple tension coordinate variables into finite difference time domain from a frequency domain, an auxiliary differential equation method and a Crank-Nicolson-Approximate-Decoupling (CNAD) algorithm are utilized, two tridiagonal matrix equations related to an electric field are obtained, and thus the calculation efficiency is obviously improved.The method has the advantages that unconditional stability is achieved, and the electromagnetic field calculation speed is increased.