114 results about "Stability study" patented technology

A system and method for accomplishing power swing blocking and unstable power swing tripping schemes during disturbances of electrical networks is disclosed. The disclosed system and method eliminates the requirement of stability studies. The no-setting scheme utilizes the swing center voltage of the electrical network to carry out its functions.

The invention belongs to the technical field of cosmetics, and particularly relates to acne treatment essence cream and a preparing method thereof. The essence cream contains aluminum starch octenylsuccinate, salicylic acid, PCA zinc, zinc gluconate, nicotinamide, tangerine orange pericarp extract, amur corktree bark extract and retinyl palmitate. The acne treatment constituents in the essence cream are obtained through screening. The new acne treatment constituents in the essence cream can effectively restrain propionibacterium acnes. Experimental studies prove that a good acne treatment effect can be realized by adding the acne treatment constituents to the essence cream. Stability studies show that the essence cream has higher stability.

The invention belongs to the technical field of slope stability measurement and discloses a rock high slope stability analysis three-dimensional geomechanical model test method and the application thereof. The stability of the rock high slope is evaluated through a geomechanical model test method based on temperature rise, intensity reduction and lifting overload. The disclosed method comprises the whole test process, namely, the process of model design, model material test, model manufacturing, measurement system installation and model test. According to the method, the slope deformation distribution characteristics, the damage process and the damage mechanism can be obtained, the overall stability safety coefficient of the slope is obtained. Therefore, the overall stability of the high slope is evaluated. Finally, the method is applied to stability research of the high slope of the left bank dam abutment of the crane beach hydropower station. The initial cracking safety coefficient Kof the high slope is obtained. The initial cracking safety coefficient K ranges from 1.030 to 1.058. The limit safety factor k limit is equal to 1.417-1.579, and the overall stability of the slope isevaluated.

The invention discloses a multi-point displacement meter installation and automatic data collection method of a steeply inclined seam roadway. The method includes the steps of 1 hole drilling, 2 multi-point displacement meter installation and 3 automatic anchoring data collection. The hole drilling includes the steps that according to lithology deformation of the steeply inclined seam roadway, the direction along a dip angle is selected to be drilled for laying multi-point displacement meters. The multi-point displacement meter installation includes the steps that firstly measuring rods with anchor heads, protection pipes, exhaust pipes and grouting pipes are poked into drilled holes, the exhaust pipes and the grouting pipes are placed according to the direction of the drilled holes, then bases are fixed through a cement mortar accelerating agent, grouting is conducted for hole sealing, and finally displacement sensors are installed. The automatic anchoring data collection includes the steps that a data line of each displacement sensor is led into an intelligent data collection device, half-bridge connection is adopted, sampling is conducted once every day, and the frequency data of the multi-point displacement meters are collected and received automatically and stored in a USB flash disk memory. The method is simple and easy to implement, simple to operate, safe and reliable and lays the foundation for further steeply inclined seam roadway supporting stability study.

The invention provides an acid sensitivity lactobacillus bulgaricus strain and the usage thereof, belonging to the biological engineering technology field. An acid sensitivity strain L.B-FM-6 which is a lactobacillus delbrueckii subsp. bulgaricus is separated and screened in the research of the natural dairy ferment-tibet kefir. The research on the storage stability of the fermented dairy product, fermented juice and the fermented vegetable juice which are fermented by the combination of the strain L.B-FM-6 and other microbial strains solves the defects of short shelf life of the active lactobacillus drink and displays the superiority of the strains in fermenting the dairy product and the juice.

The invention discloses a high- purity of osthol, structure proof with spectral analysis, method for preparation, stability study, acute toxicity study, the drug compositions containing osthol, and new drug utilities of the natural product. By the technique steps of extracted Chinese pharmacy conidium fruit with alcohol, decolorizing and enriching by large-hole adsorption resin, and separating and purifying, it can prepare osthol with a purity of above 98%. The study expresses that the osthol has a clear utility of anti-cancer, anti-auto lymphoma, and so on.

The invention provides a calculation method for judging a strong or weak alternating current and direct current hybrid system in an ultra high voltage direct current hierarchical access mode. The method comprises the following steps: establishing a characteristic equation of the system according to an equivalent model of the alternating current and direct current system in the ultra high voltage direct current hierarchical access mode; providing the definitions of a hierarchical critical short circuit ratio and a hierarchical boundary short circuit ratio; calculating the critical short circuit ratio and the boundary short circuit ratio of the alternating current and direct current system; and judging that the hybrid system is strong or weak according to the relative magnitudes of the short circuit ratio, the critical short circuit ratio and the boundary short circuit ratio. The quantitative calculation method provides a good theoretical basis for stability research of the hybrid system in the ultra high voltage direct current hierarchical access mode, and has certain guiding significance for construction and operation of ultra high voltage direct current hierarchical access engineering.

The invention discloses a test system and method for studying gravity type anchorage stability under a seismic load. The system comprises an anchorage system, a load system and a measuring system; theanchorage system is composed of a test chamber, a similar rock-soil layer, an anchorage body and a steel strand; the load system comprises a static load system and a dynamic load system; the static load system is composed of a weight, a gate-type loading frame, a pulley and the steel strand; the dynamic load system is composed of a vibrating table, a wood board and a sponge; and the measuring system comprises a precise dynamometer, an angle measurer, a micro pressure box, a laser range finder and a sound wave vibration measurer. The specific operations of the system comprise the following steps: producing a test module, arranging a monitoring system, loading the test module, debugging the monitoring system, model test testing and data recording. According to the test system for studying the gravity type anchorage stability under the seismic load provided by the invention, the simulation of different anchorage test prototypes can be realized, the dynamic response change of the anchorage body under the action of the seismic load is simulated simply and effectively, and the dynamic measurement of dynamic response data such as internal force, displacement, vibration speed and the likeof the anchorage body and surrounding rock and soil bodies in the loading process of dynamic loads is realized.

The invention discloses a deep anhydrite cavern group stability evaluation and layout optimization method in an oil storage environment. The evaluation method involved in the invention comprises four parts, i.e. deep anhydrite surrounding rock engineering geology characteristic analysis, deep anhydrite surrounding rock mechanical parameter analysis, reservoir cavern group stability study and cavern layout optimization design respectively. The method provided by the invention applies Hoek-Brwon empirical criterion and geological strength index to clarify the reduction rule of anhydrite surrounding rocks and rock mass mechanical parameters, and provides a parameter basis for cavern group surrounding rock stability numerical simulation. The invention puts forward an element safety factor method, and combines surrounding rock stress field, displacement field and plastic zone to comprehensively evaluate the cavern group surrounding rock stability. The method provided by the invention can be used for optimizing the layout scheme of deep anhydrite cavern groups in an oil storage environment, improving the oil storage efficiency of anhydrite caverns, and evaluating the stability of deep anhydrite cavern groups in an oil storage environment, and provides a reference method for scientific verification of deep anhydrite forewinning oil storage adaptability.

The invention provides a flexible ac transmission system (FACTS) interactive influence degree evaluation method based on a modal series method, which comprises the following steps: a step A of providing system running conditions in a power system containing a FACTS device; a step B of inputting basic data of the system under each system running condition; a step C of performing load flow calculation to obtain a stable equilibrium point of the system; a step D of calculating nonlinear degree indexes; a step E of performing a step F if the calculation of the nonlinear degree indexes of all the system running conditions are finished, or else returning to the step B; and a step F of comparing the sizes of all the nonlinear degree indexes. The FACTS interactive influence degree evaluation method based on the modal series method has the advantages of being strong in application and definite in physical significance, can provide accurate guide for coordinated running of a plurality of FACTS, and can serve as measuring indexes for the nonlinear degree of the system to provide research methods for the work of power system analysis, stability study and the like.

Stable non-alcoholic transdermal hydrogel of dexibuprofen was prepared by using a simple manufacturing process, and the experimental trials showed that the pH modifying agent, antioxidant and water miscible solvent are the essential excipients to obtain stable non-alcoholic transdermal hydrogel of dexibuprofen. The dexibuprofen hydrogel prepared using carbopol as a gelling polymer produced an opaque gel, whereas hydrogel prepared using hyroxypropyl methylcellulose (HPMC) as a gelling polymer produced a transparent gel. There was no significant changes observed with respect to physical description, pH, assay and particularly to the related substance values when the hydrogels were subjected to the stability study at accelerated condition (40 DEG C / 75% RH) for 3 months in laminated tubes.

The invention provides a novel crystal form of a tenofovir maleate, a preparation method and a pharmaceutical application thereof. The novel crystal form in a salt form facilitates the more stable presence of the tenofovir ester. A study on the stability of the crystal form shows that the novel crystal form of the tenofovir ester maleate is more stable than that reported in previous documents and is excellent in flowability. The novel crystal form tremendously improves the stability during industrial production and flowability and compressibility during preparation, and greatly meets the needs of industrial production.

The invention discloses a stability study experiment table for rock ecological side slope new soil. The stability study experiment table comprises a side slope grade adjustment system, a parameter measuring system and a new soil spray-seeding system, wherein the side slope grade adjustment system comprises a base, a containing groove, an oil cylinder, a rotating shaft, a bearing pedestal, a dial and a pointer; wherein the containing groove and the rotating shaft are fixed into a whole, a bearing is installed at the end of the rotating shaft and assembled into the bearing pedestal, the bearing pedestal is fixed to the base, the two ends of the oil cylinder are connected with the base and the containing groove respectively, the dial and the pointer are fixed to the base and the containing groove respectively, and rock is laid inside the containing groove. The stability study experiment table has the advantages that on the condition of changing a side slope grade value, replacing rock and adjusting the new soil ratio and the spray-seeding thickness, the displacement, temperature, humidity and other parameters of new soil can be monitored in real time, and the influences caused by factors such as the side slope grade, the rock lithology, the roughness, the new soil ratio and thickness on the stability of the new soil can be researched.

The invention discloses an impedance calculation method of a double-fed fan rectifier based on double closed loop control, comprising establishing a relationship expression between electrical quantityand control quantity according to circuit topology and control block diagram, deriving an expression of the closed-loop impedance and verifying the expression of the closed-loop impedance. Establisha relational expression between the electrical quantity according to the circuit topology, comprising a duty ratio signal, a direct current side voltage, a grid-side voltage and a grid-side current, establish a mathematical model of current inner loop control and voltage outer loop control parts according to the control block diagram, then establish a mathematical model of phase-locked loop part according to relationship between the circuit and the control, and jointly derive an expression of the closed-loop impedance expression; finally, verify the correctness of the impedance calculation method by inputting the disturbance at different frequencies and calculating the impedance value. According to the impedance calculation method of the double-fed fan rectifier based on double closed loopcontrol, a foundation for the stability study of the double-fed fan rectifier is laid, and parameters can be adjusted by impedance analysis to avoid phenomena that harm the power system such as harmonic instability and the like.

The invention belongs to the technical field of pharmaceutical analysis, and particularly relates to an HPLC analytic method for Nicorandil-related substances. The HPLC analytic method is characterized in that a stationary phase is a reversed-phase column of carbon octadecyl silane, and a moving phase is a mixed solution of a buffer solution, methyl alcohol and tetrahydrofuran. The HPLC analytic method is quick, simple and accurate, is good in repeatability and suitable for control and stability study of the related substances, lays a foundation for formulating quality standards of the related substances, and makes drug quality control and medication safety possible. Through scaling down organic solvents and volatile salt, which have high toxicity, the acquisition time is shortened, the economic cost is lowered, the HPLC analytic method is suitable for large-scale production, and meanwhile, harms to experimenters and environments are reduced.

The invention discloses an impedance analyzing method for sub-synchronous oscillation of a thermal power unit. The method comprises the following steps: partitioning a system to be researched into a power supply and a power grid, building state space models in sequence for the power supply and the power grid, and calculating admittance function matrixes of the power supply and the power grid; then, drawing Bode diagrams of the admittance function matrixes of the power supply and the power grid on the same graph; and lastly, picking up apparent resonance points on the bode diagrams, and calculating system series connection resonance frequency and an excited axis modal according to the apparent resonance points. Based on the basic principle of the impedance analyzing method, the power supply of the thermal power unit is modeled uniformly in a state space form, and the dynamic features of a mechanical control system of the unit are included in the state space of the power supply and modeled finally in the form of electric quantity. Compared with a conventional method, the method has the advantages that sufficient calculation accuracy can be obtained, and the dynamic features of continuous frequencies can be analyzed, so that beneficial conditions are created for the stable research of an electric-electronic power system.

The invention relates to a complete plane strain similar test system capable of applying gradient strain. The whole system comprises a plurality of combined modules, a detachable combined module, a horizontal gradient strain servo control system, a vertical strain servo control system, a connecting lifting control system and a data acquisition control system. Due to the adoption of the system, a more practical test condition is provided for an urban underground construction and a mining engineering; the test system can slide freely along with a rock via the modules of two sides and limits the movement in the direction vertical to a model, so as to realize the plane strain similar test. The upper pressure under a deep geological condition can be compensated by the vertical strain servo control system, and the horizontal gradient strain is applied by the horizontal gradient strain servo control system. The test condition of the test system can be well consistent with the actual engineering condition, the results of the test are more real and more reliable, and can guide the design and construction scientifically and reasonably, and therefore a scientific test condition is provided for the stability research of geotechnical engineering.

The invention provides an R-lansoprazole crystal form and a preparation method therefor and relates to the field of medicinal chemical industry. 2[theta] values of characteristic peaks of an X-ray powder diffractogram of the R-lansoprazole crystal form are 6.01, 6.82, 8.80, 12.23, 13.33, 14.54, 17.96, 18.86, 19.91, 20.32, 20.75, 22.10, 23.08, 23.75, 26.09, 29.68 and 32.45. The preparation method for the R-lansoprazole crystal form provided by the invention is simple and is mild in conditions and stable and controllable in preparation process; and shown by stability research, the crystal form product prepared by the method has better physicochemical properties and higher stability, is suitable for being applied to pharmaceuticals and can be used for preventing and treating gastric acid related diseases when the product is applied to pharmaceutical compositions.