Data-based systematic error extraction and compensation methods based on wavelet transform in ultra-precision optical polishing.

Sub-aperture polishing is a key technique for fabricating ultra-precision optics. However, the existence of the polishing errors that are difficult to be compensated by physical modeling seriously affects the manufacturing accuracy and efficiency of optical components. To address this problem, a data-based systematic error extraction and compensation (DSEC) method was proposed to enhance the polishing accuracy on optics.

Densi-melting effect for ultra-precision laser beam figuring with clustered overlapping technology at full-spatial-frequency.

Laser beam figuring (LBF), as a processing technology for ultra-precision figuring, is expected to be a key technology for further improving optics performance. To the best of our knowledge, we firstly demonstrated CO LBF for full-spatial-frequency error convergence at negligible stress. We found that controlling the subsidence and surface smoothing caused by material densification and melt under specific parameters range is an effective way to ensure both form error and roughness.

Fourier convolution-parallel neural network framework with library matching for multi-tool processing decision-making in optical fabrication.

Intelligent manufacturing of ultra-precision optical surfaces is urgently desired but rather difficult to achieve due to the complex physical interactions involved. The development of data-oriented neural networks provides a new pathway, but existing networks cannot be adapted for optical fabrication with a high number of feature dimensions and a small specific dataset. In this Letter, for the first time to the best of our knowledge, a novel Fourier convolution-parallel neural network (FCPNN) framework with library matching was proposed to realize multi-tool processing decision-making, including basically all combination processing parameters (tool size and material, slurry type and removal rate).

Transcription factors in the development of inner ear hair cells.

Inner ear hair cells are the sensory receptors that detect and convert sound vibrations and head movements into neural signals. However, in humans, these cells are unable to regenerate if they are damaged or lost. Over thepast decade,there has been an exponential increase in interest and progress in understanding of the development of the inner ear and of hair cells, aiming to gain insights into hair cell repair or even regeneration.

Pharyngeal wall floppiness: a novel technique to detect upper airway collapsibility in patients with OSAS.

Objective: To measure pharyngeal wall floppiness (PWF) under different pressures, a novel method and technique were introduced in the present study.

Study Design: A prospective clinical study.

Subjects And Methods: Forty-seven healthy subjects (32 male; mean age, 37.

[Hyperfine structure study of binary sodium phosphates by Raman spectroscopy].

Quantum chemistry ab initio calculation was applied to study the hyperfine structure of binary sodium phosphates. A series of phosphate model clusters were designed to simulate the microstructure of phosphates with different components. Closed-shell Hatree-Fock method (RHF) and the basis sets of 6-31G (d, p) were employed to optimize structures and calculate Raman frequencies of these phosphate model clusters.

[Raman spectroscopic study of binary PbO-TeO2 glasses].

Raman spectra of lead tellurite glasses and their melts were measured. Results show that four coordinate tellurite units convert into three coordinate units with increasing the concentration of PbO, and the number of non-bridging oxygen bonds (NBO) increases accordingly in this system. Three spectral peaks in the high frequency range were assigned to stretching vibration of bridging oxygen in four coordinate tellurite units (Q(b)), stretching vibration of non-bridging oxygen in four coordinate tellurite units (Q(nb)) and in three coordinate tellurite units (T(nb)).

[High temperature Raman spectroscopy techniques and its applications].

Based on the frequency and time domain characters of heat radiation, high temperature Raman spectroscopy techniques were aralyzed and summarized. Thereby, two high temperature Raman systems were set up. One is an accumulated time-resolved macro-Raman spectroscopy system, and the other is an accumulated time-resolved and confocal coupled micro-Raman spectroscopy system.

[Analysis of different methods for denoising of high temperature Raman spectra].

Combined with time accumulated resolution and space resolution the SU-HTRS(T/S) set has been realized at Shanghai University. It is impossible to avoid noise at high temperature, so different mathematic methods, such as Savitzky-Golay method, FFT and wavelet methods have been adopted for denoising. For various noise levels, the effects of three methods on the peak location, intensity and covering area as well as the smoothing degree of the reduced spectra were analyzed.

[Ab initio calculation of hyperfine structure and Raman spectra of binary alkali metal silicates].

Ab initio calculation method of quantum chemistry was used to optimize several typical binary alkali metals silicates model clusters under restricted Hartree-Fock method with 6-31G(d) basis sets. The symmetric stretching vibrational frequency of non-bridging oxygen in the high frequency range, its Raman optical activity (ROA) and the influence of different cations of those model clusters were also calculated and evaluated with the concept of hyperfine micro-structure. It was shown that the symmetric stretching vibrational frequency of non-bridging oxygen in the high frequency range is related closely to the environmental hyperfine micro-structure, and ROA enhancement of Q3 species occurs as Q4 species is its nearest neighbor.

[Structure and Raman spectra of titanium oxides].

Under the first-principle density functional theory, structures of several titanium oxides (TiO, Ti2O3, Ti3O5, anatase and rutile) were optimized, and the obtained the structure parameter that coincides with the X-ray crystal diffraction result. The optimized structure parameters coincide well with those obtained by X-ray diffraction method. Molecular vibrational modes were also studied and assigned.

[Raman active vibrations of aluminosilicates].

Raman spectra of aluminosilicate minerals, namely kyanite, andalusite, and sillimanite and K2O-Al2O3-SiO2 glasses were recorded. Four alumino-silicon tetrahedral model clusters were calculated by self-consistent (SCF) molecular orbital ab-ini-tio calculation of the quantum chem (QC) method. The result shows a decrease tendency in Raman frequencies in the 800-1200 cm(-1) frequency region with increase in four-coordinated Al content, which is assigned to the Si--Onb symmetry stretching vibrations.

[Raman spectra study of tellurium dioxide (TeO2) crystal].

The room temperature and high temperature Raman spectra of solid/melt growth boundary layers of TeO2 grown from melt were measured by high-temperature laser-micro-Raman spectrum. By analyzing, vibrational modes of the room temperature Raman spectra peaks of TeO2 crystal from band 200-800 cm-1 were confirmed, the expansion and frequency shift of each peak of the high temperature Raman spectra were interpreted and the possible structure group of the melt was proposed. So, certain foundation for studying the growth theory of functional crystal materials was provided.

[Raman spectroscopic study of silicon-oxygen tetrahedrons microstructure in x CaSiO3.LiBO2 solid solutions].

Raman spectra of xCaSiO3.LiBO2 (by weight ratio, x = 0, 0.25, 0.