1236results about How to "Reduce temperature gradient" patented technology

Provided are: a working medium for heat cycles which has a low impact on global warming, a low temperature gradient, and a sufficiently low discharge temperature, and which exhibits excellent cycle performance (i.e. refrigeration capacity and coefficient of performance); a composition for heat-cycle systems; and a heat-cycle system. The working medium for heat cycles includes trifluoroethylene and 1, 2-difluoroethylene. Also provided are: a composition for heat-cycle systems; and a heat-cycle system which uses the working medium and the composition. It is prefereable that, in the working medium for heat cycles, the ratio of the total amount of trifluoroethylene and 1, 2-difluoroethylene be at least 20 mass%, and equal to or less than 100 mass%.

The invention discloses a high polymer material ultraviolet laser 3D (three-dimensional) printing method and device for precise temperature control. The device comprises a thermostat, a laser head, a non-contact type temperature monitoring device, a scanning galvanometer, a machining platform, a powder paving device, a machining material and a computer control system. The laser head adopts a dual-tube core structure, an inner tube and an outer tube are coaxially fixed, one or more than one gradual-change neutral filter piece is arranged between the two tubes, and the laser transmittance of the filter piece(s) is radially reduced from the inner tube to the outer tube. The method comprises the following steps: presetting the machining temperature by the control system, in the process of machining, monitoring the temperature rise condition of an object to be machined in real time under the irradiation of laser by the non-contact type temperature monitoring device, feeding back to the control system, recording the increased value of the temperature within a certain time, and obtaining the absorption capability of the material to be machined to the laser and the temperature rise degree by the system, so that according to the preset machining temperature value, the laser output power can be calculated, the laser power can be timely adjusted, and the machining temperature can be precisely controlled.

The present invention discloses a fast forming method of three-beam laser compound scanning. The method comprises the following steps of: firstly utilizing long-wavelength laser (CO2 laser) for preheating the metal powder, then utilizing short-wavelength laser (YAG or optical fiber laser) for fusing the metal powder and finally utilizing long-wavelength laser (CO2 laser) to carry out heat treatment to the frozen metal. The fast manufacturing method uses the three beams of laser to carry out compound scanning, namely uses long-wavelength laser to preheat, short-wavelength laser to fuse and then long-wavelength laser to carry out heat treatment, can realize the compound process of preheating, fusion and heat treatment of the metal powder. The three beams of laser compound scanning mode has the advantages of reducing internal stress of the metal part, avoiding warping and cracking, and improving organization and performance.