- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Investigation on Near-Infrared Quantitative Detection based on Heteromorphic Sample Pool
摘要： To enhance the detection precision of samples with scattering characteristics by near infrared spectroscopy (NIRS), this study developed a heteromorphic sample pool and established the related 2D light intensity acquisition system, which can simultaneously acquire multi-path exit light adsorption and scattering information of the samples under test. The Intralipid-20% phantom solutions in 34 samples with different concentrations were detected, while one-dimensional (1D) exit light intensity distributions and two-dimensional (2D) exit light intensity distributions on the surface of the samples were analyzed and modeled using partial least squares. In contrast with the prediction results based on the modeling method of 1D exit light intensity distribution, the modeling method of 2D exit light intensity distribution exhibits more favorable results; specifically, correlation coefficient enhanced by 2.48%, while root mean square error reduced by 6.89%. The experimental results demonstrate that using heteromorphic sample pool can effectively achieve NIRS-based detection precision and speed of chemical components in the solutions with scattering characteristics, which can provide important references for high-throughput and high-precision detection of turbid media in analytical chemistry.
关键词： two-dimensional (2D) light intensity distribution,heteromorphic sample pool,near-infrared spectrum
更新于2025-09-23 15:22:29
-
The Infrared spectrum of very large (periodic) systems: global versus fragment strategies—the case of three defects in diamond
摘要： The calculation of the full vibrational spectrum (Infrared or Raman) of very large systems (say larger than one thousand atoms) is not only very expensive, but also of relatively low interest, as in many (most of the) cases only a subset of modes, well separated from the large, diffuse bands resulting from the superposition of thousands of peaks, is used for the spectroscopic characterization of the specific system under study. Here, a fragment strategy, consisting in computing and diagonalizing a reduced (in size) Hessian matrix centered around the zone of interest, is illustrated, and its accuracy and efficiency documented, by comparison with the full Hessian diagonalization (FHD) scheme. Three test cases are considered, showing different vibrational features. They are defects in diamond: the VN3 H defect (V stands for the vacancy), where the interesting point is the characterization of the bending and stretching modes of H, well separated from the large band resulting from the perturbation of the diamond manifold; the VH4 defect (four H atoms in the vacancy, with vibrational modes related to H appearing both at high and low wave numbers); and the I2N interstitial defect, with modes in which the N atoms are involved, appearing at wave numbers not far from the manifold of the perfect diamond modes. So the three cases, apparently similar, explore three different situations of interest for the fragment strategy: (1) localized modes very well separated from the large diamond continuous band ( VN3H); (2) modes at upper border of the large diamond continuous band ( I2N ): a case in which the modes of interest appear both as separated from and merged with the large continuous band ( VH4 ). It turns out that in all cases relatively small fragments, containing from 2 to 40 atoms, permit to reproduce with high accuracy (the difference with respect to the FHD being always smaller than 5 cm?1 for the wave numbers, and a few percent for the IR intensity) the spectral feature(s) of interest, at a computational cost that is only a small fraction of the one required by the FHD.
关键词： fragment strategy,vibrational modes,large systems,Infrared spectrum,diamond defects
更新于2025-09-23 15:21:21
-
Photovoltaic organic interface for neuronal stimulation in the near-infrared
摘要： Organic materials, such as conjugated polymers, are attractive building blocks for bioelectronic interfaces. In particular, organic semiconductors show excellent performance in light-mediated excitation and silencing of neuronal cells and tissues. However, the main challenges of these organic photovoltaic interfaces compared to inorganic prostheses are the limited adhesion of conjugated polymers in aqueous environments and the exploitation of materials responsive in the visible spectrum. Here, we show a photovoltaic organic interface optimized for neuronal stimulation in the near-infrared spectrum. We adjusted the organic materials by chemical modification in order to improve the adhesion in an aqueous environment and to modulate the photoelectrical stimulation efficiency. As proof-of-principle, we tested this interface on explanted degenerated mice retinas, thus providing results on the efficiency and reliability of the device as an implant for neural stimulation.
关键词： organic semiconductors,bioelectronic interfaces,neuronal stimulation,near-infrared spectrum,photovoltaic interfaces
更新于2025-09-23 15:21:01
-
Optical properties of diamond-like carbon films prepared by pulsed laser deposition onto 3D surface substrate
摘要： It is difficult to grow uniform film by pulsed laser deposition because the spatial distribution of the laser-induced plume is a forward-directed cone-shape. A 3D-motional deposition setup was founded, and the correlative mathematical model of the film thickness on the 3D curved surface was deduced. Based on simulation and optimization, the diamond-like carbon (DLC) film was grown onto the large curved silicon substrate. According to the infrared transmittance spectra, the optical constants of the DLC film samples at different regions on the curved substrate were similar, indicating that the DLC film prepared onto the curved surface was homogeneous. Meanwhile, the deviation of average transmittance in the medium infrared band was below 2.3%, which could improve the imaging performance of the infrared detection. This research is useful to expand the application of the pulsed laser deposition in the optical field.
关键词： uniform transmittance,Raman spectroscopy,3D curved surface,Pulsed laser deposition,DLC film,infrared spectrum
更新于2025-09-23 15:21:01
-
1 kHz dual sub-pulse train picosecond radially polarized beam KGW Raman generator capable of achieving multiple optical communication wavelength
摘要： A dual sub-pulse train 1064 nm picosecond radially polarized beam pump KGW single-pass Raman generator was designed. The Stokes lines of both the 768 cm?1 and 901 cm?1 vibrational modes of the KGW Raman-active crystal were excited simultaneously. The Raman generator radiated up to seven Stokes lines in the infrared spectrum, which covered multiple optical communication channels. The overall Stokes average power reached 1.01 W, and the maximum Raman overall conversion efficiency was 23.1%. The interaction between the optical field and the Raman crystal was discussed from two perspectives of line width compression and beam quality.
关键词： Multi-wavelength KGW Raman laser,Nonlinear optics,Dual sub-pulse train picosecond laser,Infrared spectrum,Radially polarized beam
更新于2025-09-12 10:27:22
-
Photoinduced reversible isomerization of 9H-fluorene into 1H-fluorene by means of hydrogen-atom migration and the lowest electronically excited triplet state studied by matrix-isolation FTIR spectroscopy
摘要： Photoinduced reversible intramolecular hydrogen-atom migration between 9H-?uorene and 1H-?uorene isolated in an Ar matrix is found by FTIR spectroscopy with an aid of DFT calculation. The forward isomerization from 9H-?uorene to 1H-?uorene occurs upon UV irradiation (λ ≥ 295 nm), while the backward isomerization occurs upon λ ≥ 320 nm light irradiation. The less stable isomer, 1H-?uorene, is identi?ed by comparison of the measured IR spectrum with the corresponding simulated spectral pattern obtained at the B3LYP/6-31++G(d,p) level. In addition, an IR spectrum of 9H-?uorene in the T1 state is measured during UV irradiation (λ ≥ 275 nm).
关键词： Electronically excited T1 state,Fluorene,Matrix-isolation infrared spectrum,Photoinduced hydrogen-atom migration
更新于2025-09-11 14:15:04
-
Near-infrared spectra quantitative analysis for flue gas of thermal power plant based on wavelength selection
摘要： This paper proposed a near-infrared (NIR) spectra quantitative analysis method for flue gas of thermal power plant based on wavelength selection. For the proposed method, the self-adaptive accelerated particle swarm optimization is presented for determining the most representative wavelengths of NIR spectral signals and is combined with partial least square for predicting the various contents of the real flue gas dataset. The proposed method chooses the current own optimal or the current global optimal as the reference state randomly and accelerated updates of the flight velocity by the reference state, then the particle state is updated based on the new velocity self-adaptively. The experimental results of a real flue gas dataset verified that the proposed method has higher predictive ability and could overcome the premature convergence.
关键词： near-infrared spectrum,wavelength selection,fuel gas,Thermal power plant,self-adaptive accelerated discrete particle swarm optimization
更新于2025-09-09 09:28:46