5 results about "Polar crystal" patented technology

The application discloses a kind of polyvinylidene fluoride high crystallinity orientation polar crystal phase, its preparation method and application.The preparation method is by polyvinylidene fluoride particle raw material is placed in mould, first temperature is raised to above melting point and is maintained to eliminate thermal history, temperature is reduced to forming temperature 150~260 DEG C, the pressure of 50MPa~600MPa is applied immediately after being applied above shear flow field, shear flow field is applied for more than 10s, then constant pressure is reduced to sample crystallization is completed, temperature is reduced to room temperature after waiting, unloading pressure, obtain the polyvinylidene fluoride sample containing high crystallinity orientation polar crystal phase.The polyvinylidene fluoride product prepared by the method, polar crystal phase crystallinity is as high as 63%, and presents good orientation, crystalline morphology is shish-kebab structure, and related polyvinylidene fluoride sample shows excellent piezoelectric performance.The preparation method of the PVDF high crystallinity orientation polar crystal phase provided by the application is helpful to promote the application of PVDF product in piezoelectric flexible sensor field.

The invention discloses an organic-inorganic hybrid malonate polar crystal material as well as a preparation method and application thereof, and belongs to the technical field of optical crystal materials. The chemical formula of the organic and inorganic hybrid malonate polar crystal material is RbLi (C3H2O4). H2O. The invention further discloses a preparation method of the organic and inorganic hybrid malonate polar crystal material. The invention also discloses a preparation method and application of the organic-inorganic hybrid malonate polar crystal material. According to the crystal material, flexible malonic acid radical anions are used as polar functional elements, the malonic acid radical is effectively induced to generate moderate structural distortion by utilizing a synergistic cation regulation strategy of Rb < + > and Li < + >, so that the crystal is stably crystallized in a polar space group, and meanwhile, the crystal material shows excellent nonlinear optical performance and is wide in application prospect.

This invention provides a method for preparing PVDF-based piezoelectric products using a micro-injection molding process based on anti-chain relaxation. The method involves melt-blending 94–98.5 parts by weight of PVDF, 1–5 parts by weight of ionic liquid, and 0.5–1 parts by weight of one-dimensional / two-dimensional carbon-based conductive filler to obtain a polyvinylidene fluoride composite material. This material is then injected into a mold for the desired piezoelectric product using a micro-injection molding machine, resulting in the PVDF-based piezoelectric product. This method utilizes the strong shear field involved in the micro-injection molding process to promote the orientation of PVDF molecular chains. Combined with the introduction of ionic liquid to induce the formation of polar crystals in the PVDF piezoelectric material and suppress the local thermal relaxation behavior of the PVDF molecular chains, this significantly reduces PVDF chain relaxation, facilitating the formation of a highly oriented β-polar phase and substantially improving the piezoelectric performance of PVDF-based piezoelectric devices.

The application belongs to the technical field of middle infrared thermal emission control, and more particularly relates to a method and device for electrically driving narrow-band middle infrared thermal emission controlled by a polar substrate. The method provided by the application completely abandons the dependence on the design and processing of complex micro-nano structures, and only uses the intrinsic phonon properties of the polar crystal substrate and the electro-thermal effect of the low-dimensional material to achieve narrow-band and polarized emission, thereby greatly simplifying the implementation path, reducing the process cost and being conducive to large-scale preparation. In addition, the method creatively applies an electric signal as a core driving step, instead of traditional overall thermal heating, so that the intensity of thermal emission can be modulated in real time, quickly and programmably. While obtaining structural simplicity, the method first gives high-speed dynamic electric control capability to the thermal emission source without micro-nano structures, and solves the long-standing technical contradiction.

The application relates to the technical field of strong laser nonlinear frequency conversion, in particular to a method for generating ultra-wideband mid-infrared laser in a single piece of polarized crystal. The method uses laser with a wavelength of 800 nm as pump light, laser with a wavelength of 0.95-1.6 microns as signal light, and a difference frequency conversion process occurs in the polarized crystal, thereby generating mid-infrared laser with a wavelength of 1.6-5 microns. In the method, a polarized crystal with a chirped period structure is used, that is, the polarization period of the crystal continuously changes with the position in the crystal. The polarized crystal is a 5% magnesium oxide doped chirped period lithium niobate crystal. The application utilizes quasi-phase matching technology, can use the maximum effective nonlinear coefficient of the chirped period lithium niobate crystal, and does not need to change the crystal angle or the polarization of the laser when the pump light is at different wavelengths. The application overcomes the shortcoming that the wavelength of the current mid-infrared band laser is difficult to expand due to the limitation of the gain medium.