36results about How to "Measurement has no effect" patented technology

This invention discloses a low-cost device performing online real-time detection and management on a DC system bus and the insulation state of by-passes, which is widely applicable to the detection and management for the insulation states of the power operation power supply systems, solar photovoltaic grid-connected systems, DC power supply systems, and HVDC high voltage DC power supply which have various specifications. The DC insulation monitor consist of a resistance bridge among the DC positive electrode, the DC negative electrode and the ground, a leakage current sensor on each DC by-pass, a voltage measurement circuit group and a master controller. The DC insulation monitor greatly reduces requirement for the leakage current sensor and can be realized through the traditional Hall current sensor without the expensive magnetic modulation current sensor, so that the system cost is greatly reduced.

The invention relates to a differential anti-jamming current amplifying circuit with two channels, wherein a first and a second input ends of an electric current-voltage convertor are used as a first and a second input ends of the invention, and reference voltage ends of the first and the second input ends are used as a first and a second reference input ends, the output ends of the first and the second electric current-voltage convertors are respectively connected with positive input ends of a first and a second differential amplifiers, the first and the second reference input ends are respectively connected with negative input ends of the first and the second differential amplifiers, the output ends of the first and the second differential amplifiers are respectively connected with a positive-negative input end or a negative-positive input end of a secondary differential amplifier, and the output end of the secondary differential amplifier is the output end of the invention. The invention successfully measures weak signal of pien grade under the condition without a screen, measuring signal-to-noise ratio can be further improved under the condition with the screen, and non-electric common mode interference signal of vibration, thermal drift and the like can be inhibited.

The invention discloses a SRAM timing sequence test circuit and a test method. The test circuit comprises a SRAM memory cell and a test circuit unit. The test circuit unit comprises a first mode switching circuit connected with the SRAM memory cell, an edge signal trigger circuit connected with the first mode switching circuit and a second mode switching circuit connected with the edge signal trigger circuit. The first mode switching circuit has a first enable pin. The second mode switching circuit has a second enable pin. According to signal control difference of the first and second enable pins, a first annular oscillating circuit and a second annular oscillating circuit are respectively formed in the test circuit; and output oscillation periods of the two annular oscillating circuits are measured so as to accurately obtain time value of reading data of the SRAM memory cell. The test circuit provided by the invention can be completed by an automatic wiring tool, and has advantages of small measuring error, high precision and simple measurement.

The invention relates to a method for separating and purifying a chemical element by use of an oxidation extraction-reduction back-extraction method. In order to solve the problems that the existing oxidation extraction-reduction back-extraction method can not give consideration to the needs for decontamination effect and mass-spectrometer measurement when in separation and purification of ruthenium and the like, the invention provides a separation and purification method of ruthenium in an irradiation uranium target. With an oxidation extraction-reduction back-extraction method, the separation and purification method comprises the following steps of: (1) dissolving the irradiation uranium target with hot nitric acid, and extracting to remove uranium and plutonium; (2) evaporating the raffinate to dryness, dissolving the obtained substrate with dilute sulphuric acid, and adding dilute sulphuric acid containing Ce(SO4)2 to oxidize ruthenium into RuO4; (3) adding carbon tetrachloride to extract RuO4; (4) washing the organic phase with dilute sulphuric acid twice; and (5) performing back extraction of ruthenium by taking the aqueous solution of dilute ascorbic acid as an aqueous phase to obtain ruthenium back-extraction liquid. The separation and purification method provided by the invention realizes a good decontamination effect and a high yield of ruthenium; the selected oxidation and reduction back-extraction conditions are reasonable and appropriate; and the ruthenium back-extraction liquid can be directly subjected to mass-spectrometer measurement.

The invention discloses a α-Fe 2 o 3 Nano microsphere hydrogen sulfide gas sensitive material and the preparation method of gas sensitive element, with FeCl 3 ·6H 2 O is the raw material, [C 12 -2-C 12 im]Br 2 As an auxiliary reagent, it was reacted in a stainless steel self-pressurized reactor at 150-210°C for 8-12 h by hydrothermal method, cooled naturally to room temperature and then centrifuged. The product was washed several times with ethanol and ultrapure water, and vacuum-dried to obtain α ‑Fe 2 o 3 nanospheres. α‑Fe 2 o 3 The precursor was calcined at 250 °C for 2 h to obtain α‑Fe with a porous structure 2 o 3 Nano microsphere hydrogen sulfide gas sensitive material. The beneficial effect of the present invention is to adopt ionic liquid type Gemini imidazole surfactant ([C] for the first time 12 -2-C 12 im]Br 2 ) assisted in the synthesis of α-Fe with self-assembled porous structure 2 o 3 The nano-microsphere hydrogen sulfide gas-sensing material has opened up a new way for the development and real-time detection of harmful gas gas-sensing new materials.

The invention relates to a method for measuring parallel grid line zero-sequence capacitance. The zero-sequence capacitance is measured through a single-phase power, a distributed power generator and a mutual inductance measuring device, one end of the mutual inductance measuring device is connected with three-phase guide lines through three connecting branch lines, and the other end of the mutual inductance measuring device is connected to the ground; the single-phase power is connected at one connecting point of the three connecting branch lines through a line, and the distributed power generator is connected to a line connected to the grounding end of the mutual inductance measuring device through a line and is connected with the single-phase power. Compared with the prior art, the method is convenient to use and easy to measure, by means of test, the adjacent parallel lines are on different grounding conditions, measuring results of the zero-sequence capacitance are consistent, so that the measuring results are accurate.