The value of PH and conductivity of meat were studied as two indicators of freshness, the relationship between PH and conductivity with freshness were obtained by adopting least squares fitting algorithm, and both these indicators can well characterize the relationship of freshness in the permissible error range. The models to predict the value of PH and conductivity based on near-infrared reflectance spectroscopy were established. The correlation coefficients R2 were 83.43% and 84.79%, RMSECV were 0.215 and 0.0703 for PH and conductivity of calibration model, respectively. Test the external prediction sample set by the optimization models, the prediction mean square error (RMSEP) were 0.271 and 0.0768, the regression coefficient of predicted value and actual value were 87.28% and 86.7% for these two indicators. Combine the relation formulas and the prediction values we can indicate the freshness of meat quickly and non -invasively.

Applying laser–speckle techniques in the material sciences as well as in methods to characterize surface conditions of specimen has become the method of choice especially if a non–contacting principle is sought. This is almost always the case for specimen that are small in at least one dimension as for example in the material testing of foils, fibres or micromaterials and certainly also if elevated test–temperatures are preventing standard gauges.In this paper some widely overlooked sources of errors that — if unavoidable — increase measurement uncertainty beyond the theoretical limit attainable are discussed and the magnitude of their influence is detailed.In particular the following effects are considered: The laser–source wavelength stability as well as its pointing stability, the effects caused by so–called schlieren occuring along the optical path as well as temperature effects causing changes in the systems geometry, thermally influencing the optical parameters of the imaging optics as well as the often overlooked and in most illumination systems unknown radius of curvature of the laser wavefronts used to illuminate the specimen. Small though as these influences seem, they might contribute significant uncertainties especially in material testing applications where the strain ε = ℓ, ℓ is to be determined out of consecutive measurements of usually small changes in overall length ℓ of the specimens geometry parameter. Typical values of ε are bounded by ±2000 ppm (the typical range of Hooke’s law for steel). So values of ℓ on the order of tenth of micrometers for typical gauge lenghts around 50 mm yield ppm resolutions for ε. Analyzing the above mentioned error sources one can quickly see that all of them, if not taken care of appropriately, carry the potential to cause significantly larger deviations than the resolution sought after demands.

The present study is focused on the angle measurement with the combination of coarse and fine gratings to simplify the structure of measuring instruments at the same accuracy. A series of experiments were completed by using the He-Ne laser and the gratings with the periods of 83.37um and 6.325um, which shows that the accuracy of the angle measurement is better than 2′. The experimental results indicate that the proposed method is avail to simplify the instrument and improve the accuracy.

Photobiological safety related to LED products is currently being addressed in IEC 62471-2006 / CIES009/E：2002. High-power LEDs with attached output optics generally have complex beam profiles. The measurements of weighted radiance and irradiance for maximal exposure related to photobiological safety classification of LED optical radiation are very different from those of traditional luminance/illuminance, and are not tractable yet to any national laboratories. The main features include,
a. Photobiological response weighted, e. g. by BLH spectral function
b. Field of view related to the exposure duration
c. Incidence aperture as eye’s pupil
d. Accessible maximal exposure
e. Focusing on the apparent sources, not true sources
The retinal hazard caused by LED optical radiation is a considerable dominant effect, which includes thermal burn and photochemically induced retinal injury. For white LEDs based on blue LED chips and yellow phosphor, the main hazard is the photochemical retinal injury caused by blue radiation of high color temperature, high luminance area of LED products. The hazard functions for both thermal and photochemical hazard assessment and the spectral response V(λ) of photopic vision are entirely different. Thus it is necessary to determine the spectral radiance of LED from 300 nm to 1400 nm, whose spectral range is wider than that of normal commercial instruments, and the measurement shall be in accordance with the optical hazard principle to human eyes.

It was in the microwave frequency range of 8.2 GHz to 12.4 GHz that a polymerhyl methacrylate(PMMA) Double-Prism system has been built. In this system, using a parabolic transmitter antenna and a wave-absorbing slab with a electrically large size slot, the finite-sized quasiparallel Guass beam as light wave can be guarenteed when incident source is sufficiently far. In consequence, discretely sampling from 9.25GHz to 12.25GHz, measured the Goos-Hänchen (GH) effect of total reflection beam for TM polarization at the air gap of width 4mm, where the frustrated internal total reflection(FITR) phenomenon has been realized, and at the air gap of width 20mm.,where the internal total reflection has not been destroyed. However, the observed values are not in agreement with theoretical predictions provided by Artmann. So, the nonideal nature of real world sources must be included for accurate interpretation of experimental results. Eventually, the measurement results have been successfully verified through the Fourier optics method of angular spectrum based on source edge diffraction considerations.