Two-dimensional self-assembly and co-assembly of two tetracarboxylic acid derivatives investigated by STM.

In this work, the two-dimensional self-assembly and co-assembly behaviors of two tetracarboxylic acid derivatives (H4BDETP and H4BTB) were investigated by scanning tunneling microscopy (STM). H4BDETP molecules self-assembled into linear nanostructures, and H4BTB molecules formed lamellar and tetragonal nanostructures. The formation of a H4BDETP/H4BTB co-assembly nanostructure was closely related to the deposition sequence of H4BDETP and H4BTB on highly oriented pyrolytic graphite (HOPG). The introduction of H4BTB into the self-assembly system of H4BDETP resulted in the emergence of the H4BDETP/H4BTB nanostructure, while the addition of H4BDETP had no effect on the self-assembly system of H4BTB and a H4BDETP/H4BTB co-assembly nanostructure was not obtained.

Study of 256 fiber array biaxial LiDAR optical assembly measurements.

This paper presents a method for measuring the optical assembly results based on multi-beam biaxial LiDAR. This method analyzes the optical assembly parameters of a LiDAR system affecting the LiDAR operation, and an experimental measurement system is built using a collimator to simulate the infinity imaging field. An InGaAs infrared camera is used to take pictures of the laser spot from the LiDAR transmitter and receiver, and then fit the laser spot images with Gaussian equations to calculate the biaxial LiDAR optical assembly results. Finally, the possible effecting factors of LiDAR alignment results are analyzed. This method is experimentally proven to achieve the measurement of the optical assembly results of a large scale multi-beam LiDAR. The possibility of further optimizing the measurement method by shaping the transmit laser is also reported.

Enhanced Flexible Poly(vinylidene fluoride-trifluorethylene) Piezoelectric Nanogenerators by SnSe Nanosheet Doping and Solvent Treatment.

Organic piezoelectric nanogenerators (PENGs) with light weight, good flexibility, and simple processing are promising in mechanical energy conversion. Here, a high-output polymer PENG composed of a poly(vinylidene fluoride-trifluorethylene)/SnSe nanosheet (NS) nanocomposite film has been fabricated and tested. After a treatment with mixed solvents of N,N-dimethylformamide and 1,1,2,2-tetrachloroethane (TCE), the optimal nanocomposite PENG exhibits high piezoelectric properties with a piezoelectric coefficient (d33) of 25.06 pC·N-1, a prominent open-circuit voltage (Voc) of 15.36 V·cm-2, and a short-circuit current (Isc) of 1.02 µA·cm-2. Moreover, the PENG can generate an output power density of up to 10.72 µW·cm-2 under a vertical force of 50 N. The attractive piezoelectric performance results from the doping of SnSe NSs with a high piezoelectric coefficient and also the increased ß-phase ascribed to the introduction of nucleating agent NSs and the TCE solvent. The PENGs reveal great application potentials in consumer electronics.

A small molecular electron acceptor based on asymmetric hexacyclic core of thieno[1,2-b]indaceno[5,6-b']thienothiophene for efficient fullerene-free polymer solar cells.

A novel A-D-A (acceptor-donor-acceptor) type non-fullerene small molecule, A201, consisting of an asymmetric thieno[1,2-b]indaceno[5,6-b']thienothiophene (TITT) unit as middle D part and 2-(3-oxo-2,3-dihydroinden-1-ylidene) malononitrile (IC) groups as end-capped A parts was designed and synthesized. The asymmetric TITT building block showed a higher dipole moment of 0.85 Debye (1 Debye = 3.33564 × 10-30 cm) compared with the symmetric analogues of indacenodithiophene (IDT) and indacenodithieno[3,2-b]thiophene (IDTT) of 0.098 and 0.13 Debye, respectively. The solution-processed bulk heterojunction solar cells using a benzotriazole (BTA)-based polymer of J71 as donor and A201 as acceptor, showed a power conversion efficiency (PCE) of 9.36% with an open-circuit voltage (Voc) of 0.88 V, a short-circuit current (Jsc) of 13.15 mA cm-2, and a fill factor (FF) of 0.67, under the illumination of AM 1.5G at 100 mW cm-2. The high PCE of this material combination could be attributed to its broad absorption spectrum and the high hole mobility (µh) and electron mobility (µe) of 9.56 × 10-4 and 5.17 × 10-4 cm2 V-1 s-1, respectively. These results indicate that the asymmetric electron-donating segments are promising to construct A-D-A type small molecular acceptors, which could largely enhance the diversity of building blocks to design photovoltaic materials.

Fate and removal of various antibiotic resistance genes in typical pharmaceutical wastewater treatment systems.

The high levels of antibiotic residues in pharmaceutical wastewater treatment plants (PWWTPs) make these plants the hotspots for the proliferation of antibiotic resistance genes (ARGs). This study investigated the fate and removal of 11 ARG subtypes for sulfonamide, tetracycline, ß-lactam, and macrolide resistance in each processing stage of two full-scale PWWTPs in northern China. The levels of typical ARG subtypes in the final effluents ranged from (2.56 ± 0.13) × 10(1) to (2.36 ± 0.11) × 10(7) copies/ml. The absolute abundance of ARGs in effluents accounted for only 0.03-78.1 % of influents of the two PWWTPs, while the majority of the ARGs were transported to the dewatered sludge with concentrations from (2.65 ± 0.43) × 10(5) to (4.27 ± 0.03) × 10(10) copies/g dry weight (dw). The total loads of ARGs discharged through dewatered sludge plus effluent was 1.01-14.09-fold higher than that in the raw influents, suggesting the proliferation of ARGs occurred in the wastewater treatment. The proliferation of ARGs mainly occurs in biological treatment process, such as aeration tank, anoxic tank, sequencing batch reactor (SBR), and bio-contact oxidation, facilitates the proliferation of various ARGs, implying significant replication of certain ARG subtypes may be attributable to microbial growth. Chemical oxidation seems promising to remove ARGs, with removal efficiency ranged from 29.3 to 85.7 %, while the partial correlation analysis showed significant correlations between antibiotic concentration and ARG removal. Thus, the high antibiotic residues within the PWWTPs may have an influence on the proliferation, fate, and removal of the associated ARG subtypes.

[Stokes Parameter Detection and Precision Analysis Based on Rotating Quarter-Wave Plate].

The accuracy of the calibration reference source polarization states directly influences the precision of the polarized optical remote sensor calibration, and thus affects the inversion accuracy of the characteristics of targets. In this paper, 870 nm horizontal linear polarized light has been chosen as the tested calibration reference light, modulated by rotating quarter-wave plate(QWP). The intensity as a Fourier series of the rotation angle of the plate and its coefficients were demodulated with the Fourier transform method, Stokes parameters can be calculated with these coefficients. The mean, standard deviation, composite uncertainty and relative deviation of measured data compared with the theoretical value of the ten measurement results were presented. In order to improve the accuracy of the measurement, the correction model for the quarter-wave plate retardance deviation Δδ, fast axis angle deviation Δα and the transmission axis alignment deviation Δß of analyzing polarizer has been constructed. In this model, detection deviation of Stokes parameters is described as a function of Δδ and Δß, Δδ and Δß were determined by the function and magnitude of the deviation. Combined with quarter-wave plate fast axis angle deviation which was the result of simulation to adjust the experiment device, and then detecting the calibration reference source polarization states again. The experimental results show that, the difference between measured value and theoretical value of Stokes parameters reduced to less than 1.41% from 3.77% relative to without correction. The experiment principle, device and deviation correction model of this research can significantly improve the accuracy of detecting the polarization state of the calibration reference light source.

[Automatic Field Calibration and Analysis of Satellite Based on Hyper-Spectral Ratio Radiometer].

With the demand of calibration technology of high frequency and high precision in terms of the optical remote sensing satellite of China, and the deficiency of the artificial work, the automatic system of hyper-spectral ratio radiometer was developed by investigation the calibration situation of domestic and abroad satellite, then the automatic calibration of satellite sensor was carried out. According to the parameters demand of field calibration and the goal of automation, the ratio radiometer was designed to measure global spectral irradiance by integrating sphere, and the diffuse spectral irradiance was measure by the shelter, so the diffuse-global ratio was calculated by these data. Simultaneity the ground radiation was measured with radiometer optical-lens and the automatic observation of atmospheric and surface radiation characteristics was achieved, In addition, the data pre-processing of real-time and remote transmission were integrated in the system. With the field test on the Dunhuang radiometric calibration sites in 2015, the radiometer worked in an ideal way, and the atmospheric optical parameters and surface reflectance data were acquired, which support the calibration of satellite sensor. The comparison with the traditional measurement was carried, the relative deviation of the surface reflectance is less than 5%, and the absolute deviation of the atmospheric parameters is less than 5% and the diffuse ratio is less than 0.015%. According to the measured data and based on irradiance-based method, the field calibration applied to the band 1~5 of Aqua MODIS, the relative deviation of band 1~4 is less than 1% while the band 57.24%, so the requirement of the automatic calibration of the satellite sensor was satisfied preliminarily.