Raman spectroscopy is a novel method of food analysis and inspection. It is highly accurate, quick, and noninvasive. The investigation and monitoring of food processing is important because most of the foods humans eat today are processed in various ways. In this article, the use of Raman spectroscopy in food processes, such as fermentation, cooking, processed food manufacturing, and so on, are explored. The characteristics and difficulties of the Raman inspection of these processes are also discussed. According to the various research reports, Raman spectroscopy is a very powerful tool for monitoring these food processes in lab environments and is likely to see usage in situ in the future.

Visible and near infrared spectroscopy has long been used to predict fruit internal quality, with portable instrumentation advantageous for in-field use. We developed a handheld spectrometer using a linear variable filter (LVF) and a complementary metal-oxide-semiconductor (CMOS) linear detector array. The LVF is a bandpass filter with a centre wavelength changing linearly in one direction and can replace a grating as the light-dispersion component. An LVF was designed and fabricated specifically to work in the 620–1080 nm region and for the analysis of fruit. The optical design used an improved collimator and an LVF to yield a compact, stable and low-cost optical engine. By using a CMOS detector and other suitable electronics, the spectrometer achieved a low power consumption. The spectrometer can analyse spectral data using an onboard prediction model and can be operated from a remote smartphone, tablet or laptop computer. This paper details the design of the spectrometer and the results of its resolution and stability tests. The spectrometer operated with a resolution of less than 1.5% centre wavelength and a signal-to-noise ratio of up to 5000. The spectrometer was then used to predict the sugar content in pears. The optimised model provided an R²c value of 0.96, standard error of calibration value of 0.29 °Bx and standard error of prediction value of 0.46 °Bx. The results indicated that this LVF-based spectrometer is promising for measuring the internal quality of fruit.

In order to improve the image quality of the aerial optoelectronic sensor over a wide range of temperature changes, high thermal adaptability of the primary mirror as the critical components is considered. Integrated optomechanical analysis and optimization for mounting primary mirrors are carried out. The mirror surface shape error caused by uniform temperature decrease was treated as the objective function, and the fundamental frequency of the mirror assembly and the surface shape error caused by gravity parallel or vertical to the optical axis are taken as the constraints. A detailed size optimization is conducted to optimize its dimension parameters. Sensitivities of the optical system performance with respect to the size parameters are further evaluated. The configuration of the primary mirror and the flexure are obtained. The simulated optimization results show that the size parameters differently affect the optical performance and which factors are the key. The mirror surface shape error under 30 °C uniform temperature decrease effectively decreased from 26.5 nm to 11.6 nm, despite the weight of the primary mirror assembly increases by 0.3 kg. Compared to the initial design, the value of the system’s modulation transfer function (0° field angle) is improved from 0.15 to 0.21. Namely, the optical performance of the camera under thermal load has been enhanced and thermal adaptability of the primary mirror has been obviously reinforced after optimization. Based on the optimized results, a prototype of the primary mirror assembly is manufactured and assembled. A ground thermal test was conducted to verify difference in imaging quality at room and low temperature, respectively. The image quality of the camera meets the requirements of the index despite degrading.

Thin films of manganese-doped indium oxide (IMO) deposited by electron beam evaporation have been investigated as anodes in organic light-emitting diodes (OLEDs). The IMO films have a high work function of 5.35 eV, a desirable surface morphology with an average roughness of 1.1 nm, a high average optical transmittance of 87.2% in the visible region, and a maximum optical transmittance of 92% at 460 nm. It is demonstrated that an IMO anode can effectively improve hole injection at the anode/organic interface, resulting in OLEDs with an increased electroluminescent efficiency.

Double-crystal monochromators (DCMs) are one of the most critical optical devices in beamlines at synchrotron sources, directly affecting the quality of the beam energy and position. As the performance of synchrotron light sources continues to improve, higher demands are placed on the stability of DCMs. This paper proposes a novel adaptive vibration control method combining variational modal decomposition (VMD) and filter-x normalized least mean squares (FxNLMS), ensuring DCM stability under random engineering disturbance. Firstly, the sample entropy of the vibration signal is selected as the fitness function, and the number of modal components k and the penalty factor α are optimized by a genetic algorithm. Subsequently, the vibration signal is decomposed into band frequencies that do not overlap with each other. Eventually, each band signal is individually governed by the FxNLMS controller. Numerical results have demonstrated that the proposed adaptive vibration control method has high convergence accuracy and excellent vibration suppression performance. Furthermore, the effectiveness of the vibration control method has been verified with actual measured vibration signals of the DCM.