100 results about "Thermal hysteresis" patented technology

The magnetic material for magnetic refrigeration according to the present invention has an NaZn₁₃-type crystalline structure and comprises iron (Fe) as a principal element (more specifically, Fe is substituted for the position of “Zn”) and hydrogen (H) in an amount of 2 to 18 atomic % based on all constitutional elements. Preferably, the magnetic material for magnetic refrigeration preferably contains 61 to 87 atomic % of Fe, 4 to 18 atomic % of a total amount of Si and Al, 5 to 7 atomic % of La. The magnetic material for magnetic refrigeration exhibits a large entropy change in a room temperature region and no thermal hysteresis in a magnetic phase transition. Therefore, when a magnetic refrigeration cycle is configured using the magnetic material for magnetic refrigeration, a stable operation can be performed.

The invention discloses a temperature controlling method for a satellite-borne rubidium clock temperature-control cabin and belongs to the technical field of spacecraft thermal control. Firstly, the maximum power needed by additional heating of a heater is detached, so that multiple one-way heaters with low power are formed. Secondly, thermal hysteresis time of the one-way heaters is calculated so as to design a control time interval of each one-way heater, after control of all the heaters is finished according to the time intervals, a complete heating and control period is formed. A system is provided with a backup temperature sensor and the heaters, when a main temperature sensor is effective or the main heater incorrectly responds to a controller switch order, primary backup switch is finished. The method for controlling the temperature and automatically dealing with a fault can provide high-precision and high-stability temperature control for the working environment of a rubidium clock. The control method is simple, high-efficiency, reliable and capable of meeting the requirement for long-time orbital continuous and stable work.

The present invention discloses a method for using an open-type rubber soft die for realization of a thin-wall I-beam structure composite material part, by a machine manufacturing method, a metal false part with a boundary dimension which is entirely consistent with the boundary dimension of the composite material part is processed, a rubber soft die molding mold with a baffle is also processed, a rubber soft die is paved and pasted in a cavity formed by the metal false part and upper and lower templates, the external part of the rubber soft die is vacuum-sealed with a vacuum bag, and the rubber soft die is molded in a hot-pressing tank; after the rubber soft die is molded, the vacuum bag is removed, the metal false part is taken out, and filled with a composite material, then the external part of the rubber soft die is vacuum-sealed with the vacuum bag, and thee rubber soft die is molded in the hot-pressing tank to obtain the I-beam structure composite material part. The method can avoid the thickness over-deviation phenomenon of the composite material part, avoids the thermal hysteresis phenomenon, effectively guarantees the molding quality of the part, and improves the passing rate and efficiency of production.

A guide wire that due to its wide elastic region and high Young's modulus, simultaneously has pliability and pushability, and that even when its surface is coated with a plastic material of high melting point, is highly impervious to influences of heat treatment, and that has excellent slidability and excels in weldability between a distal-end-side base material and a proximal-end-side core material. The guide wire has a core material comprising a distal-end-side core material and a proximal-end-side core material. The distal-end-side core material is made of an iron alloy having shape memorycapability and superelasticity, consisting essentially of two phases of gamma-phase and gamma'-phase and exhibiting, in a thermal hysteresis of martensite transformation and reverse transformation, adifference between reverse transformation completion temperature (Af-point) and martensite transformation starting temperature (Ms-point) of 100 DEG C or below. The proximal-end-side core material ismade of an alloy containing iron and has an elastic modulus higher than that of the distal-end-side core material. The distal-end-side core material and the proximal-end-side core material are weldedtogether.

The invention discloses a LaFeSi based magnetic refrigeration composite material and a preparation method and application thereof. The LaFeSi based magnetic refrigeration composite material comprises functional body components such as LaFeSi based alloy particles and matrix components such as low-melting-point metal or alloy, and the LaFeSi based alloy particles are bonded and coated by the matrix components to form a bulk material; and the LaFeSi based alloy particles are of a NaZn13 type structure. According to the LaFeSi based magnetic refrigeration composite material and the preparation method and application thereof, composite hot pressing is conducted between the cheap and easily-obtained low-melting-point metal or alloy and the LaFeSi based alloy particles, the appropriate low-melting-point components are selected, the pressing pressure, the hot pressing temperature, the pressure maintaining time and the like are adjusted, and thus the high-thermal-conductivity LaFeSi based magnetic refrigeration composite material can be obtained; the magnetic entropy change of the LaFeSi based magnetic refrigeration composite material is less reduced compared with that before hot pressing, the magnetic hysteresis loss is low, and thermal hysteresis is avoided; and in addition, the process is simple and easy to operate, the process conditions are relatively mild, energy consumption is little, the cost is low, the repeatability is good, and the preparation method can be widely used in preparation of magnetic refrigeration materials.

An iron-based alloy having shape memory properties and superelasticity, which has a composition comprising 25-35% by mass of Ni, 13-25% by mass of Co, 2-8% by mass of Al, and 1-20% by mass in total of at least one selected from the group consisting of 1-5% by mass of Ti, 2-10% by mass of Nb and 3-20% by mass of Ta, the balance being substantially Fe and inevitable impurities, and a recrystallization texture substantially comprising a γ phase and a γ′ phase, particular crystal orientations of the γ phase being aligned, and the difference between a reverse transformation-finishing temperature and a martensitic transformation-starting temperature being 100° C. or less in the thermal hysteresis of martensitic transformation and reverse transformation.

A digital-to-analog converter is disclosed, comprising an input/output circuit, a bistable circuit connected with the input/output circuit, a clock circuit connected with the input/output circuit and the bistable circuit, and a current generator circuit connected with the clock circuit. The clock circuit acts as a switch, providing current from the current generator either to the input/output circuit or to the bistable circuit. The digital input signal switches when the current generator provides current to the bistable circuit, and switching of the input signal is asserted at the output of the converter when the current generator provides current to the input/output circuit. Therefore, switching of a clock circuit signal, rather than switching of the digital input signal determines switching of the output signal, in order to reduce intersymbol interference of the converter associated with thermal hysteresis of some of the components of the converter.

A wide thermal hysteresis TiNiNb shape memory alloy memory ring and its preparation method and application, characterized in that the alloy components of the memory ring are Ti: 42-47; Ni: 44-49; Nb: 6-14; the preparation method is : 1) Melting: Melting by vacuum ultra-pure smelting technology; 2) Homogenization treatment: 700-1000°C, time 3-6h; 3) Forging at 700-900°C; 4) Hot drawing at 400-750°C Wire is required; 5) The wire is wound into a ring and welded by micro-beam plasma welding technology; 6) The diameter is expanded under the condition of -60°C. The memory ring prepared by the present invention has the characteristics of high connection strength, small space occupation, light weight, and convenient installation. It can be used for storage and transportation at -190°C-+60°C ambient temperature, and can be used at -60°C-+ after fastening. Keep fastening without loosening in the range of 200°C.

A method includes the steps of: introducing insulation film into a trench to provide a trench isolation; planarizing the trench isolation to expose a passivation film; and removing the passivation film and depositing a second silicon layer on a first silicon layer and the trench isolation; and in the step of depositing the first silicon layer the first silicon layer is an undoped silicon layer and in the step of depositing the second silicon layer the second silicon layer is a doped silicon layer or an undoped silicon layer subsequently having an impurity introduced thereinto or the like and thermally diffused through subsequent thermal hysteresis into the first silicon layer.

The invention discloses a room temperature magnetic refrigeration alloy material. The room temperature magnetic refrigeration alloy material is represented by the molecular formula of Mn1-XAlXCoGe; and the alloy material comprises 33.3-34.4% of manganese element, 0.6-2.7% of aluminum element, 32.8-33.3% of cobalt element, and 30.2-32.7% of germanium element in percentage by mass. The invention also provides a preparation method for the room temperature magnetic refrigeration alloy material. The preparation method comprises the steps of adding reactive materials into a vacuum arc furnace, vacuumizing until the pressure is lower than 10<-4>Pa, and pumping argon gas in; smelting the sample repeatedly; and taking out the sample and cooling the sample, putting the sample into a high-temperature-resistant quartz glass tube, vacuumizing, inflating the high-temperature-resistant quartz glass tube with high-purity argon for performing gas washing, then putting the high-temperature-resistant quartz glass tube into a furnace type box, taking the sample out and performing annealing to obtain the room temperature magnetic refrigeration alloy material. According to the preparation method, the Curie temperature of the alloy is obviously reduced to the temperature close to the room temperature, the thermal hysteresis phenomenon occurring close to phase change is effectively avoided, and a relatively wide adjustable temperature range close to the room temperature is obtained.