Photoinduced Construction of Thieno[3,4-c]quinolin-4(5H)-ones/Selenopheno[3,4-c]quinolin-4(5H)-ones Using Diphenyl Disulfide or Diphenyl Diselenide as Sulfur or Selenium Sources.

A photocatalytic synthesis of thieno[3,4-c]quinolin-4(5H)-ones/selenopheno[3,4-c]quinolin-4(5H)-ones using diphenyl disulfide or diphenyl diselenide as sulfur or selenium sources was developed. Two C-S/Se bonds and one C-C bond were constructed simultaneously without transition metals and other additives.

Automatic acquisition method for evaluating the on-orbit modulation transfer function based on lunar targets.

In view of the existing method having a great subjectivity for the lunar edge selection, we propose an automatic knife-edge detection method based on the Hough transform to evaluate the on-orbit modulation transfer function (MTF) of the satellite remote sensor. This novel method avoids the dependence of the on-orbit MTF measurement on the edge selection location, overcoming the limitation of the traditional method needing to identify the lunar shape and fix its edge area. On basis of two different edge detection algorithms (Sobel operator and Prewitt operator), the binary edge images of the moon are acquired, thus obtaining a series of edges satisfying the determination requirement by the Hough transform, and the MTFs corresponding to each knife-edge are calculated to obtain the optimal MTF. The automatic knife-edge detection method greatly improves the accuracy of the lunar edge selection, and the MTF obtained by the novel method is obviously better than that of the traditional method. In order to verify the effectiveness of the novel method, the long time series of the on-orbit MTFs for the FY-2G and FY-2E satellite measurements are given, indicating that the FY-2E observation has higher stability and better performance compared with that of the FY-2G satellite. This study has an important practical significance for evaluating the on-orbit stability of the satellite its optical imaging quality.

Four-quadrant retarder array imaging spectropolarimeter for the full Stokes vector spectrum.

Aiming at the major demand for polarization information gap in earth observation and space exploration, we proposed a four-quadrant retarder array imaging spectropolarimeter (FQRAISP) in view of the existing technical problem of the spectral resolution degradation along with spectral aliasing crosstalk. The optical schematic diagram of the FQRAISP together with its interference model was conceptually described, and the effectiveness of the scheme was validated through the experimental simulation, which demonstrated the competitive efficiency and accuracy in the proposed FQRAISP. The FQRAISP could restore the incident Stokes vector spectrum without any errors, and the inversion accuracy was increased by seven times, avoiding the spectrum aliasing and channel filtering in the channel modulation. In order to evaluate the influences of the alignment deviation of four-partition phase retarder component, together with its thickness deviation on the reconstructed Stokes parameters, the numerical simulations were carried out, and the results showed that the alignment deviations had a relatively weak effect on the reconstructed Stokes spectra, while the thickness deviations had an obvious influence. Therefore, the alignment deviations controlled in a range of [-0.43∘,+0.43∘] and [-0.22∘, + 0.22∘] together with the thickness deviations in a range of [ - 0.03µm, + 0.03µm] were an optimal choice for the engineering implementation of the FQRAISP. This research provided a novel method for the hardware realization of the accurate acquisition of all-optical information, having broad application prospects in remote sensing (deep space exploration), biomedicine and other fields.

Fe-S Catalyst Generated In Situ from Fe(III)- and S3•--Promoted Aerobic Oxidation of Terminal Alkenes.

An iron-sulfur complex formed by the simple mixture of FeCl3 with S3•- generated in situ from K2S is developed and applied to selective aerobic oxidation of terminal alkenes. The reaction was carried out under an atmosphere of O2 (balloon) and could proceed on a gram scale, expanding the application of S3•- in organic synthesis. This study also encourages us to explore the application of an Fe-S catalyst in organic reactions.

Transition-Metal-Free Decarboxylative Cyclization of N-Arylacrylamides with 2,2-Difluoro-2-(phenylthio)acetic Acid: Synthesis of Thiodifluorooxindole Derivatives.

An efficient transition-metal-free decarboxylative cyclization of N-arylacrylamides with 2,2-difluoro-2-(phenylthio)acetic acid for the construction of thiodifluoroindoleone derivatives is described. This strategy features stable and readily available substrates, mild reaction conditions, and transition-metal-free catalysts. Notably, this protocol has successfully applied to synthesis of gem-difluoroalkenes, which exist in numerous biologically active compounds.

Visible-Light-Promoted Cross-Coupling Reactions of Aryldiazonium Salts with S-Methyl-d3 Sulfonothioate or Se-Methyl-d3 Selenium Sulfonate: Synthesis of Trideuteromethylated Sulfides, Sulfoxides, and Selenides.

A novel visible-light-photocatalytic deuterated thiomethylation/methylselenation of aryldiazonium salts utilizing S/Se-methyl-d3 sulfonothioate has been developed. The mild conditions and the various functional groups provide a green protocol for the efficient and rapid introduction of the S-CD3 or Se-CD3 group with useful levels of deuterium content (>91% D). Trideuteromethyl sulfoxides have also been successfully chemoselectively observed by simple atmospheric changes under photocatalytic conditions.

Image quality and spectral performance evaluations of a polarization imaging spectrometer based on a Savart polariscope.

The modulation transfer function (MTF) and signal-to-noise ratio (SNR) are the key parameters to evaluate quantitatively the image quality and spectral performance in a polarization imaging spectrometer based on a Savart polariscope. In order to evaluate the image quality and reflect the detecting ability of the imaging spectrometer, calibration experiments on the MTF, SNR, and spectral resolution were carried out and some important conclusions were obtained. For incident radiance values 4.464, 3.119, and 0.523 w/m2·sr, the average SNRs of the interferogram were 500, 400, and 200 dB, respectively, and the MTF is 0.24. During the spectral resolution calibration, the maximum optical path difference was set as 57.08 µm, and the measured value is greater than the theoretical value, which is mainly caused by the structural design of the polarization imaging spectrometer. For the wavelength range of [500 nm, 600 nm], the SNR of the spectrum is lower and about 50 dB, while the SNR is obviously higher in a range of λ∈[600 nm, 960 nm]. This study provides a theoretical and practical guidance for improving the image quality and judging the spectral performance of the polarization imaging spectrometer.

Radiometric calibration of tempospatially modulated polarization interference imaging spectrometer.

The tempospatially modulated polarization interference imaging spectrometer (TSMPIIS) nominated by the Ministry of Scence and Technology, takes part in the "Eleventh Five-Year National Science and Technology Exhibition." In order to improve the detecting precision of the TSMPIIS, its radiometric calibration scheme is proposed on the basis of the solar simulator, integrating sphere, monochromator, and spectroradiometer. Under the conditions of changing the exposure time and radiant brightness, the CCD linear responses for the TSMPIIS were first tested to validate the reliability of the radiometric calibration performed with a linear response model, and the linear errors were less than 0.15% and 1.15%, respectively. A novel method is put forward to calibrate the nonuniformity of CCD pixels, and the least squares method can commendably correct the uneven effect in the spatial direction. Besides, the absolute radiometric calibration establishes a corresponding relation between the dimensionless intensity output from the TSMPIIS and the target radiant brightness. The study lays the foundation for the engineering application of the TSMPIIS, such as remote sensing detection, and has an important significance for the development of our instrument and equipment technology with independent intellectual property rights.

Multiple frequency bands of square split resonant rings and metal wire metamaterial.

This work presents experimental measurements of two square split resonant ring and metal wire (SSRR-MW) samples with different cell sizes at microwave frequencies. The geometrical sizes of the metamaterial cells are found to play an important role in the resonant frequency. Cells with different geometrical sizes are chosen to stack into a two-layer or three-layer metamaterial unit to realize the multiple negative passbands. The effective parameters of three separate SSRR-MW models (a one-layer unit, a two-layer unit, and a three-layer unit) are retrieved from the simulation data. The composed models exhibit two or three negative bands by overlapping the passbands of original cells and broadening the overall bandwidth. The recovered parameters show good agreement with the theoretical analysis.

Modulation depth of static four-phase-divided wind imaging interferometer.

The static four-phase-divided imaging interferometry is a new technology of passive detection for the upper atmospheric wind field. It is featured with real-time detection, no moving parts, stability, and so on. In this paper, its basic theory is discussed, and its characteristics are briefly introduced. Furthermore, its key technical parameter, modulation depth, is analyzed. The relationships of modulation depth with the incident angle and temperature of the working environment are derived by using computer simulation. It is shown that the modulation depth decreases with the increase of the temperature and incident angle. The study provides a theoretical basis to increase the modulation depth of the interferometer, and it is of significance for the development of the upper atmosphere detection technique and theory.

Optical throughput of the Sagnac interferometer with a modified large optical path difference.

The basic principle of Sagnac interferometer with modified large optical path difference is expounded on in this paper. According to the Fresnel formula, electromagnetic field energy, and energy flux, the transmittance and reflectance of each interface of a Sagnac interferometer are calculated, respectively, and then the exact expressions of the optical throughput changing with the incident angle, the angle of the incident plane, and paper plane (the bottom plane of Sagnac interferometer) and Sagnac interferometer acute angles are given. Furthermore, we analyze the effects of various parameters on the optical throughput by computer simulation, and some important conclusions are obtained. This work is of great scientific significance to the static, real-time simultaneous detection of upper atmospheric wind field.