There are two types of negative refractive index material phenomenon. A class of materials is due to resonance mechanisms leading local permittivity and negative permeability at the same time, both have an effective negative refractive index material. Seam ring resonator arrays of such materials is also known as metamaterials (Metamaterials) .Smith, who belong to a specific material. However, the slit-ring resonator array structure having a large loss and a narrower bandwidth negative refraction, in the application will be subject to many restrictions. Another type of photonic crystal material is propylene glycol, which itself does not have an effective negative refractive index, but the complexity of the dispersion relation in certain special circumstances photonic band will lead to negative refraction. Propylene glycol manufacturers offer in the photonic crystal, electromagnetic waves in periodic structures in Bragg scattering mechanism plays a major role. Although local and nonlocal resonance mechanism of Bragg scattering mechanism will produce negative refraction, but two mechanisms have their own characteristics. For Bragg mechanism, people have a clearer understanding of propylene glycol-shelf, through appropriate selection photonic crystals and photonic band structure design, you can get the desired negative refraction passband. But Bragg mechanism requires periodic structure to the lattice constant compared to the wavelength of electromagnetic energy gap intends wholesale high quality glycol, microwave band structure is too large will cause the device to limit the application of Abbe refractometer optical system shown in Figure 4. On the dial marked in accordance with the formula for a series of values ??of n, when the crosshair reticle center alignment and dark boundaries, can be read directly from the dial a test sample of n values, very easy to use. Amici prism for eliminating chromatic dispersion on the boundary line, and therefore, although the use of white light instead of monochromatic light, still obtain a colorless and clear dividing line between light and dark. Abbe refractometer to measure the refractive index in the range of 1.3 to 1.7, the accuracy Δn = ± 3 × 10-4. Xiang dry chemical (Figure) _ _ Heilongjiang factory direct propylene glycol provided by the Jinan Chemical Co., Ltd., Cheung dry. Jinan Cheung Dry Chemical Co. (www.xiangqianhuagong.com) (www.dilunyierchun.com) adhere to the "people-oriented" business philosophy, has a professional staff, and strive to provide the best products and services to contribute to the community, and welcome to new and old customers to visit us and sincere cooperation for a better future. Xiang dry chemical - your trusted friend, Company Address: Industrial Road chemical market, Contact: Mr. You can also access (www.dilunyierchun.com/supply_details_39988415.html), for more information about the company.