275 results about "Stability assessment" patented technology

This invention relates to a strain monitor system for slope distributed fibers, which lays out several parallel special optical cables along the slope or at least lays out one close to the slope top and the corner separately, adheres symmetrically two fibers on the outer surface of a tilt testing tube to get the distortion of deep soil helped by the strain of the tube, the special optical cables are melted orderly to constitute a sensor circuit to be connected to BOTDR, which links with remote computers via local computer and internet to constitute distributed fiber strain monitor system and gets the distortion or displacement of the slope by integrating and summing the measured strain distribution further to evaluate and preset to the side slope.

The invention provides a method for transient stability assessment and real-time control of an electric system. According to the method, technologies concerning knowledge discovery are introduced to realize the stability assessment and the control of the electric system; and on the basis of establishing a transient stability assessment model, the corresponding relation between the system running condition and the overall stability of the electric system is found out, the inherent running discipline of the electric system are grasped, and the fast assessment of the stable running state of the electric system is realized, therefore, the actual running management of the electric system can be guided. The method has the advantages that timely and effective stability control scheme can be established for the running state which loses stability after great disturbance, and the safe and the stable running of the system can be ensured at lowest price.

The invention belongs to the technical field of the analysis of power systems, and provides a method which is suitable for screening expected fault in online transient safety and stability assessment. The transient safety and stability of a certain expected fault in the power system are closely related to the running state of the power system. In the invention, influences of other factors in the running state of the power system on a transient safety and stability margin are calculated based on a quantitative analysis method of the transient safety and stability by adopting a margin-time function in which the transient safety and stability margin decreases as time increases after key influence factors such as a clustering mode, the change of an output force, the change of a load, the charging and discharging of an element and the like of a generator are taken into comprehensive consideration; an estimation and mode determination method of the transient safety and stability after the running state of the power system is changed is put forward; and time domain simulation is not carried out any more for the expected fault of which an estimated value is larger than a threshold, so that the calculation speed of the online transient safety and stability assessment is increased.

Based on the definition and classification of the power system stability both at home and abroad in combination with an appraisal procedure of the power system reliability, the invention provides a concept of voltage stability in case of large disturbance probability, based on the concept a reliability index of voltage stability in case of large disturbance probability is established, the reliability index can comprehensively take into account temporary and long-term voltage stability, and a comprehensive evaluation principle of probability voltage stability is formulated. Based on the reliability index and the comprehensive evaluation principle, a method for appraising voltage stability in case of large disturbance probability based on power system reliability appraisal is invented, and an applied algorithm process for the probability voltage stability appraisal established by the method can provide a quantitative appraisal result on the security feature of the system voltage stability.

A novel method for real-time small-signal stability analysis for power electronic-based components in a power system. The method is based on impedance measurement techniques and Generalized Nyquist Criterion. The method is capable of real-time application. The method may be used to monitor a system in real-time by perturbing the system persistently and utilizing the system's responses to calculate source/load impedance in time-domain and based on d-q impedance measurement theory. Time-domain results may be transferred to frequency-domain results by taking advantage of a fast Fourier transform algorithm (or optionally discrete Fourier transformer for discrete systems) and monitoring the system's stability by obtaining a Nyquist contour and employing Generalized Nyquist Criterion or unit circle criterion.

The invention discloses a river critical levee section washing safety analysis and bank slope stability judgment method. The method comprises the steps of 1, generating a data set used for constructing a two-dimensional river channel water/sand model; 2, setting model calculation parameters and definite solution conditions according to river reach parameters in the research area, and constructing a two-dimensional water/sand numerical simulation model of the research area; step 3, setting various working conditions according to sand coming conditions under different flood conditions, simulating river water/sand transportation and river bed silt flushing of a research area by utilizing a two-dimensional water/sand numerical model, analyzing dangerous river beds before and after flood based on a simulation result, and respectively calculating river dangerous bank slope river bed depth flushing distance and river lateral erosion distance; and step 4, constructing a finite element model for seepage-stability analysis of the bank slope of the critical levee section, and quantitatively researching the relationship between each factor and the bank slope stability safety coefficient. According to the method, the stability of the riverway dangerous work bank slope under the action of water flow flushing is studied, and a quantitative means is provided for critical levee section stability evaluation.

The invention discloses a proficiency testing sample for measuring the color fastness to perspiration of a textile and a preparation method of the sample. The proficiency testing sample is formed by dyeing a piece of pure cotton weaving tabby bleaching grey cloth by adopting an active dye or a direct dye, the detection result of the color fastness to acidic perspiration (which comprises an original sample discoloration level number, a cotton lining staining level number and a wool lining staining level number) is within 2 level-5 level and contains the daily detection range of the color fastness to acidic perspiration in the field of existing textile clothing, and the proficiency assessment of the detection items of different laboratories or the quality control usage of the laboratories can be realized. The preparation method of the proficiency testing sample has the advantages of easiness and convenience for operation, high success rate and high practicability; the prepared proficiency testing sample can be stored and transported at normal temperature and meets the uniformity and stability assessment guide requirement of a CNAS0GL03 proficiency testing sample in the aspects of uniformity and stability.

A micro-implantable apparatus and method for the stability assessment of a two-stage dental implant during Osseo integration processes, whose detection device is based on a transmission of a pulse wave signal from an upper opening of an implant and a subsequent analysis of the reflection waves that measure the changes in mechanical interlock between the bone and the implant resulted from the wound healing processes happened at the gap between bone-implant interface. The incorporation of RF coils in the detection device provides a mean to transmit and to receive the detection waves, which makes it possible for such a device to be operated in a wireless setting. This device also includes an energy storage, which serve as a temporary power supply unit to effectively eliminate the need for signal wires and power cores, which in turn further increases the applicability and safety of such a device as a passive, implant able apparatus.

The invention discloses a voltage stability assessment method for a multi-infeed AC/DC hybrid power system. On the basis of a multi-infeed effective short circuit ratio considering shunt capacitor compensation, a reactive power conversion factor is adopted for describing an influence degree on voltage of a DC system by a shunt capacitor compensation point in an AC system, a conversion method is adopted for acquiring reactive power influence quantity on the DC system by a shunt capacitor connected with each compensation point in the AC system, reactive power influence quantities on the DC system by all shunt capacitor compensation points in the system are accumulated, and bad influences on voltage stability of the DC system by whole system shunt compensation are acquired. According to the whole system reactive power influence quantities, the effective short circuit ratio is acquired, influences included in shunt capacitor compensation are further acquired, and stability of the power system is assessed according to the effective short circuit ratio. Compared with the current AC/DC hybrid power system voltage stability assessment method on the basis of the multi-infeed effective short circuit ratio, the method provided by the invention has high accuracy, and provides a basis for planning and operation of a multi-DC infeed power grid system.

An implantable cardiac stimulation system provides capture threshold stability assessment. The system includes an implantable pulse generator that provides pacing stimulation pulses, an implantable lead system that couples the pulse generator to a patient's heart, and a capture threshold test circuit that performs capture threshold tests with the pulse generator and provides capture thresholds at spaced apart times. A capture threshold processor responsive to the capture thresholds provides capture threshold stability indicia. The capture threshold stability indicia may be a threshold stability index equal to the ratio of the peak-to-peak threshold fluctuation and the mean capture threshold. The threshold stability index may be compared to a given standard to determine if the capture thresholds are unstable.

The present invention discloses a multi-attribute decision tree power grid stability margin assessment method based on linear discrimination analysis. a key variable discovery model is established based on the offline simulation data and the real-time monitoring data of a power grid to perform effective screening of historical sample data to reduce the data dimensions, a combination relation model among key variables is established to discover the association relation among the variables, extract combination features capable of reflecting important degree contrast of each variable, establish the association relation between the power grid operation state and the transient stability margin, determine the main reasons of system stability level changing, form a concise and accurate knowledge rule base and regulate the decision reference so as to rapidly assess the current stability level according to the system operation state, provide quantification information support for operators' auxiliary decisions and improve the standardization, the rapidity and the adaptive capability of the power grid stability assessment, and therefore the multi-attribute decision tree power grid stability margin assessment method based on the linear discrimination analysis has wide application prospects.

A method for evaluating confidence of measuring parameters of a strap-down air-borne gravimeter includes: (1) evaluating accuracy and stability of a sensor of the strap-down air-borne gravimeter; (2) evaluating initial alignment accuracy of the strap-down air-borne gravimeter; (3) evaluating integrated navigation accuracy of the strap-down air-borne gravimeter; (4) evaluating carrier acceleration calculating accuracy; and (5) integrating evaluation parameters by reflecting confidence of a measuring data source through the accuracy and the stability of the sensor, reflecting confidence of data acquisition and calculation in measuring process through performance parameters in the measuring process, accordingly calculating final measuring results, namely, calculating confidence indexes of gravity anomalies, respectively calculating confidence of an acceleration meter, a gyroscope, initial alignment, integrated navigation and carrier acceleration calculating accuracy, and finally distributing corresponding weight of the calculated confidence to evaluate the confidence of the sensor of the strap-down air-borne gravimeter. The method has the advantages of simple principle, fine operability, high practicability, easiness in popularization and the like.

A method and apparatus for determining the stability of dispersions and emulsions accelerates the onset of significant particle agglomeration in a sample by stressing the sample by reducing the height of the interparticle potential energy barrier between the particles. This is achieved by adding one or more of three stress factors: changing the pH of the sample to reduce the surface charge on the particles; adding an adsorbing electrolyte so that ions of the appropriate charge are adsorbed onto the surfaces of the particles to reduce the net charge on the particles; and applying a monovalent, divalent, or trivalent salt to partially screen electrostatic repulsions between the charged particles. In a preferred embodiment, the increase in agglomeration is detected with single particle detection, such as SPOS, to generate a PSD from which a figure of merit is derived. Another embodiment detects turbidity or light scattering to generate a value X indicative of the extent of agglomeration.

The invention relates to a Pin-SVM (Support Vector Machine)-based transient stability evaluation method for a power system. The method comprises the following steps: establishing an original feature set comprising training sample data and test sample data; training a transient stability evaluation model of the power system by the training sample data; carrying out stability evaluation on a power system state simulated by the test sample data by using the transient stability evaluation model of the power system; for the fault type of the actual power system, classifying the faults according to the membership degree of a power system feature subset relative to the stable class and unstable class of the power system, if the power system belongs to the unstable class, then the fault being a serious fault; otherwise, the fault being a nonserious failure; obtaining an evaluation index when the fault screening and stability evaluation are completed. According to the method provided by the invention, the feature set dimension and the redundant information can be reduced, and the feature dimension can be reduced, and the evaluation accuracy is higher. The method can be applied to the online safety and stability evaluation of the regional power system in China, and the safe and stable operation of the complex power system is powerfully ensured.

The invention discloses a parachute unfolding process stability assessment method of a Mars parachute bag combination and relates to a parachute unfolding process stability assessment method and belongs to the technical field of aerospace. The parachute unfolding process stability assessment method adopts six-degree-of-freedom modeling, can conduct simulation analysis on center of mass motion in the parachute unfolding process and can also conduct simulation and assessment on parachute cabin gestures and the stress situations of hanging belts. Due to the fact that the established six-degree-of-freedommodel of the parachute cabin combination is simplified, the flow field analysis and flexible body modeling process can be omitted on the premise that it is ensured that simulationconforms to the actual physical situation, and the assessment and simulation efficiency is improved. The parachute unfolding process stability assessment precision and assessment efficiency of the Mars parachute bag combination can be improved, data support is provided for parachute and cabin parameter configuration, and the times and design costs of physical testing are reduced. In addition, the parachute unfolding process stability assessment method is feasible to different cabin type Mars landing tasks and is high in repeatability and wide in application range.

Disclosed is a thread making technological parameter dynamic quality stability characterization method. The method comprises the steps that stable-state data and unstable-state data of a technological parameter in thread making procedures are collected; the deviation degree and the dispersion degree of the stable-state data and a technology index of the technological parameter are worked out according to the stable-state data; the unqualified time of the technological parameter is calculated according to the unstable-state data; the deviation degree and the dispersion degree of the technological parameter and the unqualified time of the unstable-state data are converted respectively according to a preset dynamic quality stability evaluation function in the stable-state process and a preset dynamic quality stability evaluation function in the unstable state process, and a dynamic quality stability assessed value of the stable-state data and a dynamic quality stability assessed value of the unstable-state data are of the technological parameter are acquired respectively; whether the dynamic quality stability assessed value of the stable-state data and the dynamic quality stability assessed value of the unstable-state data of the technological parameter reach corresponding preset threshold values respectively or not is judged, and if a dynamic quality stability assessed value does not each the preset threshold values, the executing process of the technological parameter is correspondingly adjusted, controlled and optimized. The thread making technological parameter dynamic quality stability characterization method achieves the optimized effect which is more comprehensive and is more in line with reality.

The invention provides a uniaxial bidirectional synchronous control and electromagnetic loading dynamic shear test device and test method. The uniaxial bidirectional synchronous control and electromagnetic loading dynamic shear test device comprises a support platform, a loading rod part system, an electromagnetic pulse transmission system, a normal pressure servo control loading system and a datamonitoring and acquisition system. On the basis of the test device, dynamic shear test study of rock materials can be carried out under constant normal pressure under the conditions close to the actual work conditions, and complete rock samples with different test sizes or joint rock samples with single structure surfaces can be selected according to test demands to carry out study of dynamic shear mechanical characteristics and shear damage rules under the condition that the strain rate is 10<1>-10<3> s<-1>, so that important theoretical basis and technique support are provided for design, construction, protection and safety and stability evaluation of rock engineering, structure engineering and the like.

The embodiment of the invention discloses a method for evaluating the stability of the foundation of a mining infection zone. The method comprises the following steps: selecting a line route direction and a tower position of a transmission circuit passing the mining infection zone; determining motion deformation parameters of ground surface of the mining infection zone close to the tower position and in a preset width range of the line route by the acquired rock parameter of the mining infection zone and mining influence parameters; and obtaining the result of evaluating the stability of the foundation according to the motion deformation parameters. According to the embodiment of the invention, the method can realize the evaluation on the stability of the ground surface close to the tower position and in the preset width range of the transmission circuit route, thereby meeting the evaluation requirement on the stability of the foundation of the ultra-high voltage line passing the mining infection zone. The embodiment of the invention also provides a method for erecting the tower of the mining infection zone, which ensures smooth construction of the ultra-high voltage line in the mining infection zone.

The invention discloses a computer-system-based handwritten signature stability evaluation method. The method comprises the following steps of: acquiring a signature to be tested and a signature sample set of the same writer by using handwriting input equipment or extracting the signature to be tested and the signature sample set of the same writer from the conventional signature database, wherein the signature to be tested is a handwritten signature requiring stability analysis, and the signature sample set is a handwritten signature set for the stability calculation of the signature to be tested; performing signature similarity evaluation on each signature sample in the signature sample set and the signature to be tested by adopting signature segmentation matching calculation and locally-matched segment difference calculation, obtaining the number of signature samples similar to the signature to be tested in the signature sample set according to signature similarity evaluation, and comparing the number with a preset threshold value to judge whether the signature to be tested is stable or not to finally finish the stability evaluation of the signature to be tested. The handwritten signature stability evaluation method is careful and comprehensive, and signature detail information extraction problems which are neglected by the conventional handwritten signature stability evaluation method are effectively solved.

The invention discloses an evaluation method of the stability of lithium-ion battery positive and negative electrode paste. The method comprises the steps that viscosity variation in the process that the rotating speed changes from low to high and viscosity variation in the process that the rotating speed changed from high to low are tested respectively, and two curves of the paste viscosity changing along with the rotating speed are drawn respectively; the repeatability of the curves of the paste viscosity changing along with the rotating speed is analyzed, the stability of the positive and negative electrode paste is judged afterwards, when the repeatability of the two curves is good, it is shown that the stability of the positive electrode paste or the negative electrode paste is good, and when the repeatability of the two curves is poor, it is shown that the stability of the positive electrode paste or the negative electrode paste is poor. By means of the evaluation method of the stability of the lithium-ion battery positive and negative electrode paste, the stability of the paste can be judged very rapidly and easily, the reproducibility of the test is very good, the test is very accurate, the practicability is very good, and a very effective and practical method can be provided for stability evaluation of the lithium-ion battery positive and negative electrode paste.

The invention relates to a method for constructing an underground reservoir in an ancient gully of an ancient underground river channel. The method comprises the following steps: investigating the ancient gully of the ancient underground river channel, designing an underground reservoir dam body, designing an anti-seepage dam body in the reservoir area of the underground reservoir, carrying out stability assessment on the underground reservoir dam body, constructing the underground reservoir dam body, constructing the anti-seepage dam body in the reservoir area of the underground reservoir, surveying and mapping a longitudinal profile of the underground reservoir and calculating the volume of a water-bearing rock-soil layer of the underground reservoir, the water storage capacity of the underground reservoir and the average water separation quantity of an underground water-bearing layer; scientifically utilizing the water storage capacity of the underground reservoir and carrying out recharge and water replenishment on the underground reservoir. The method has the beneficial effect that aiming at the riverbed geology and the landform of the ancient gully of the ancient underground river channel, the characteristics of the water-bearing layer of the ancient gully of the ancient underground river channel as well as the supply conditions of a water source, the anti-seepage problem of various different water-bearing rock-soil layers and problems about the type selection of an underground water dam, the design of dam height and dam crest overflow section elevation, the recharge and the water replenishment of the underground reservoir and the improvement of water supply continuity of the reservoir can be systematically solved.

A non-contact apparatus for a stability assessment of a dental implant is provided. The non-contact apparatus includes a triggering device and a dental implant containing a root body and an impact generating device, wherein the root body has a cavity, the impact generating device is located in the cavity, and the triggering device provides a non-contact impetus for triggering the impact generating device.