The dissemination of the secondary standard is performed via calibration of gamma-ray measuring instruments using gamma-ray irradiator sources.  The main gamma-ray exposure unit contains three 137Cs and two 60Co sources of different activity....

The design of the IOL standard for dioptric power is based on the definition described in ISO 11979. Two structure forms are chosen to realize the calibration of corresponding instruments. One is convex-plane and the other is concave-plane form....

A high-accuracy equipment for radius of curvature (ROC) measurement was developed by the project group with Beijing Institute of Technology. It is based on laser differential confocal technique, which can measure the ROC of various optical...

Ophthalmometer is an important ophthalmic instrument widely used in the field of contact lens fitting and refractive surgery for the measurement of human corneal radius of curvature and corneal refractive power of front surface. Measurement...

The traceability of key parameters of Raman spectrometry was researched by theoretical analysis and experimental measurement. The method of tracing the peak position and relative response to wavelength primary standard and photometric lightness...

NIM developed and established Primary Standard for Vertex Power in 2002， which is the highest standard established for eyeglass industry in China. It includes five sets of primary standard test lenses and one primary standard measurement device...