33 results about "Conditional stability" patented technology

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.

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 at the bottom, some columns with small cross sections, an ring buoyancy tank at the middle part, some columns with large cross sections, and an upper drilling equipment and oil gas processing module. 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 drilling equipment 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.

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 discloses an unconditional stability and conditional stability mixed time domain spectral element electromagnetic analyzing method. In a traditional time domain spectral element method, for complex models, especially under the condition of containing multiscale problems, the sizes of meshes obtained through hexahedral subdivision are not uniform. In the subsequent time iteration, in order to ensure that an algorithm is stable and not diverging, the time step is set according to the size of the minimum subdivision mesh, and therefore the whole solution process wastes a large amount of time. The invention provides the self-adapting unconditional stability and conditional stability mixed time domain spectral element method. Small meshes and large meshes are automatically found out through the self-adapting method, an ordinary central difference format is used for the large mesh area, and a Newmark-beta difference format is used for the small mesh area, so that the unconditionally stable iteration format is obtained, the whole time step can be very large, and the solution time is greatly shortened.

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 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.