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Additive passivation can be an effective strategy to regulate and control the properties of organic–inorganic halide perovskite film. In this article, carbon quantum dots (CQDs), fabricated by non-focused laser irradiation of carbon nanomaterial diluted in anti-solvent ethyl acetate, denoted as EACQDs, were adopted for perovskite film defect passivation and modification of carbon-based CH3NH3PbI3 perovskite solar cells (PSCs). The size of EACQDs can be tuned by manipulating the laser fluence. The morphology of perovskite film was uncovered through scanning electron microscopy and atomic force microscopy. After embedding of EACQDs, the defect in perovskite crystal was reduced, resulting in the decreased carrier recombination and accelerated carrier transportation, which were demonstrated by electrochemical impedance spectroscopy, photoluminescence and time-resolved photoluminescence. As a consequence, with the optimization of 0.01 mg/mL EACQDs (1064 nm–300 mJ·pulse−1·cm−2–10 min), the power conversion efficiency (PCE) of carbon-based PSCs achieved a maximum value of 16.43%, which improved 23.81% when compared with the pristine PSCs of 13.27%. Furthermore, the EACQDs optimized PSCs also exhibited an excellent stability and still retained 86% of its initial PCE after 50-day storage at the room atmosphere with a humidity of 30–50%.

Bilge water is a significant source of pollution in the marine environment and has captured widespread international attention. In this study, a sequencing batch reactor (SBR) combined with strain S2 identified as Bacillus licheniformis was employed to assess the biodegradation of Chemical Oxygen Demand (COD) from bilge water. The influencing variables such as temperature, pH level and inoculum concentration on the performance SBR system were optimized by utilizing response surface methodology (RSM). The experimental results showed that the maximum COD removal of 77.81% was reached at the optimal SBR operation conditions of temperature 35.44 °C pH 8.13, and inoculum concentration 31.47 mL. In the practical application of SBR, it was found that the decrease in hydraulic retention time (HRT) was accompanied by a decrease in COD degradation rate. The biodegradation kinetics of COD in bilge water were well fitted with the first-order equation with a higher R

The efficient development of selective adsorbents for uranium extraction from seawater is necessary for their potential application in nuclear power generation. The amidoxime-based adsorbents have been recognized as the potential candidates, whereas they still suffer from a much higher affinity towards V(V) present in the seawater over U(VI), leading to the extremely limited commercial use. In this work, we develop a novel mussel-inspired photothermal polyamidoxime (PAO) hydrogel adsorbent, in which polydopamine (PDA) chains are linked to PAO (PDA-PAO) via Michael addition. Dual-crosslinked Fe@PDA-PAO hydrogel structure is constructed by noncovalent bonds between the catechol of PDA chains (e.g. π-π stacking and hydrogen bonds) as well as ionic coordination of Fe3+. PDA contributes to the improved hydrophilicity and high photothermal conversion efficiency. As a result, after immersing in real seawater for 6 weeks, light-irradiated Fe@PDA-PAO hydrogel delivers high uranium sorption capacity (12.67 mg-U/g-Ads) together with high U/V mass ratios (1.17), which are superior to currently available hydrogel adsorbents. Meanwhile, Fe3+ coordination endows Fe@PDA-PAO hydrogel with excellent tensile strength and self-recovery ability, which are of great significance to withstand the harsh conditions of ocean environment for practical applications. The results presented here reveal that Fe@PDA-PAO hydrogel holds tremendous potential for practical applications in the uranium-selective extraction from seawater.

Additive modification can be a meritorious method for performance enhancement of perovskite solar cells (PSCs). In this work, as a superior charge carrier transportation material, WS2 quantum dots in anti-solvent are generated by pulsed laser irradiation and subsequently embedded in perovskite film to reduce the grain boundary barriers and accelerate charge transport via favorable band alignment, as can be proved by ultraviolet photoelectron spectroscopy (UPS). Besides, X-ray photoelectron spectroscopy (XPS) tests reveal the interaction of WS2 quantum dots with Pb2+ via Pb–S bonds, indicating the suppressed uncoordinated Pb2+ trap states. Thus, the reduced defects and superior band alignment in PSCs will lead to the decreased charge recombination and excellent charge transport, which can improve the efficiency of PSCs. As a result, the highest power conversion efficiency (PCE) of 16.85% is obtained through WS2 quantum dots modification with an optimum concentration of 0.1 mg/mL in anti-solvent, which is substantially promoted when compared with the pristine PSCs (13.27%). Moreover, the modified device sample can still keep 71% of the original PCE after 50-day conservation indoor with a humidity of 30–50%. This work can provide a novel fast and convenient method for WS2 quantum dots fabrication and the potential applications in PSCs.

With the aim to improve the accuracy of laser triangulation measurements, this paper proposes to analyze the error caused by different colors of a measurand surface and proposes a compensation method. By investigating the fundamentals of laser triangulation, the color error is obtained via the Phong model, while the relationship between the measurement error and color is obtained through experiments. Based on the above results, a color error compensation method is proposed, which produces a color-error library according to the error of the different colors. Thus, the correlation between the error and color of the measurand surface is also calculated. The experimental data demonstrates that this method can reduce the error to 10% and maintain the color measurement error to within 90 μm. Moreover, this technique is of great significance to measure a measurand surface with different colors.

Fiber-shaped supercapacitors with remarkable flexibility and considerable energy-storage capacity have become the promising candidates in the field of wearable and portable electronic devices. In fact, both of the mechanical properties and electrochemical performance are in need of significant improvement to satisfy the practical applications of fiber-shaped supercapacitors. In this paper, a high-performance cellulose nanofibers reinforced graphene/polypyrrole microfiber is fabricated by a convenient wet-spinning strategy. The cellulose nanofibers act as both “enhancer” and “spacer”, which not only provide substantial hydrogen bonds to strengthen the interlaminar force but also prevent the restacking of the graphene sheets. This microfiber exhibits excellent tensile strength (364.3 MPa), which is superior to most of the reported fibers for supercapacitors. Meanwhile, the assembled fiber-shaped supercapacitors possess high specific capacitances of 334 mF cm−2 in liquid electrolyte and 218 mF cm−2 in solid electrolyte at the current density of 0.1 mA cm−2, which are also at the top level of fiber-shaped supercapacitors. The presented strategy combines the industrially viable wet-spinning technology and the well-designed structure for the fabrication of high-performance ternary fiber-shaped supercapacitors, providing a good reference for the development of wearable and portable energy storage devices.

In this study, anti-solvent carbon quantum dots (ASCQDs), generated via pulsed laser irradiation in chlorobenzene (CB), were adopted as an additive for defect passivation of the grain boundaries of CH3NH3PbI3 in hole-conductor-free, carbon-counter-electrode perovskite solar cells (PSCs). The size of the ASCQDs can be easily regulated by different laser fluence. The improvement of perovskite films’ morphology was revealed by scanning electron microscopy (SEM) and atomic force microscopy (AFM), which was beneficial for carrier transport. Higher photoluminescence (PL) intensity as well as prolonged carrier lifetime were proved in the ASCQDs optimized perovskite film, confirmed the laser induced ASCQDs can decrease nonradiative recombination via defect passivation, which can be further verified by the decreased defect density. As a result, the introduction of ASCQDs (1064 nm-50 mJ pulse−1 cm−1-10 min) led to a champion efficiency of 14.95%, which improved 14.04% when compared with pure CB treated PSCs (13.11%). Furthermore, the ASCQDs treated PSCs can still retain 93% and 81% of the initial power conversion efficiency after 600 h in the glovebox and in the atmosphere with humidity of 50–70%, respectively.

Metal particles with excellent conductivity can be used as additives to ameliorate the performance of perovskite solar cells (PSCs). However, it is formidable to generate stable liquid metal particles especially quantum dots because of the room-temperature fluidity. Herein, in this work, eutectic gallium-indium liquid metal quantum dots (GIQDs) were prepared via pulsed laser irradiation in anti-solvent and incorporated in perovskite film to accelerate electron transport due to the superior conductivity. As a result, the charge transport resistance was decreased, leading to the fast quenching effect and short carrier lifetime at the surface of perovskite film, which were verified by steady-state and time-resolved photoluminescence. Besides, the reduced charge recombination contributed to the enhancement of current density. Moreover, after the optimization of 0.1 mg/mL GIQDs incorporated in perovskite film, the power conversion efficiency of PSCs obtained a champion value of 15.55%, which improved 17.18% when compared with pristine samples of 13.27%. This article will pave the way for binary liquid metal synthesizing and optoelectronic applications.

In this study, NaGdF4:Yb3+, Er3+@NaGdF4:Eu3+ (NGEY@NGE) core-shell rare earth nanoparticles are prepared by a simple hydrothermal method. After testing, the emission peaks are observed at 415, 525, 540 and 660 nm with an excitation light of 980 nm due to the up-conversion luminescence from rare-earth nanoparticles. Under light excitation at 395 nm, the rare-earth nanoparticles undergo down-conversion luminescence with emission peaks at 590, 610 and 695 nm. The resulting nanoparticles are introduced into the TiO2 mesoporous layer of hole-conductor-free perovskite solar cells (PSCs) based on carbon counter electrodes to broaden the spectral response of the cells from the visible range to the near-infrared and near-ultraviolet regions, which can guarantee a high light absorption efficiency and corresponding accelerated generation of electron-hole pairs. The results suggest that the mixing of NGEY@NGE nanoparticles into mesoporous TiO2 layer improves the power conversion efficiency of PSCs to 14.21%, which is 10.6% higher than that of the control cells, which can pave an effective way to improve the performance of PSCs with a broadened response range.

In this paper, a TiO2 nanowire film synthesized via a hydrothermal method was prepared as a photoanode for dye-sensitized solar cells (DSSCs). The synthesized TiO2 nanowires were characterized by t ...

Extraction of radioactive uranium from the natural seawater is regarded as one of the most promising ways to address the shortage of uranium resources. As a kind of potential uranium adsorbent, more attention has been paid to metal–organic framework materials (MOFs) due to large specific surface area and high ion selectivity. Currently, however, MOF adsorbents are hardly applied to the real seawater in view of the relatively low uranium adsorption capacity and recyclable issues. Herein, we present the monolithic MOF adsorbent with photothermally enhancing uranium adsorption capacity. Carbon sponge (CS) substrate with macroporous open cell structure was used as excellent photothermal conversion material. Zr-MOF (UiO-66-NH2) crystals were in situ grown on the fibrils network of polydopamine (PDA) pre-coated CS to obtain UiO-66-NH2@CS-PDA adsorbent. It is found that UiO-66-NH2 coating with perfect coverage and good adhesion has a high mass loading (>85 wt%). As a result, UiO-66-NH2@CS-PDA adsorbents exhibited the advantage of high-selectivity, high-affinity and cycling stability. Compared with the dark condition, the uranium adsorption amount was increased by 32.37% after 4 weeks in the natural seawater under simulated solar irradiation, which was mainly ascribed to the endothermic behavior of uranium adsorption process. Moreover, the elasticity attribute of CS was essential for sustenance of volume variation buffering during seawater flow. As a recyclable and favorable elastic large-scale monolithic MOF adsorbent, UiO-66-NH2@CS-PDA holds great promise for extracting uranium from the natural seawater.

The social and economic growth as result of promoting the rapid development of tourism in China has brought tremendous pressure on the urban transportation systems. Research of travel behavior concerning the characteristics of tourists has provided effective information for transportation planning. Due to different city plans, public transportation system design, car parking design and management, etc., the local situation in developed countries differs from the counterpart in China. However, little research has studied the factors influencing the choice of travel destinations in tourism. The research aims to study the tourism destination and mode choice behavior of tourists and provides suggestions to improve tourism transportation service system. An online questionnaire survey is used to collect data including the travel characteristics and personal attributes of local tourists in different holidays in Hangzhou, China. A multinomial logit model is constructed with the trip destination set as the dependent variable. Results show that age, residential type, car ownership, companion type and holiday length have a significant impact on destination choice. To determine what influences modal choice for such trips, a second logit model is established with travel mode set as the dependent variable with the explanatory variables of age, gender, companion type, car ownership, holiday length and travel destination found to be significant. The results demonstrated that people aged 26 to 44 prefer suburban areas, and they are the main group driving to their travel destination. Public transport use frequency decreases when the destination is located outside of the main tourist area. Finally, suggestions have been proposed to mitigate the congestion and parking problem based on model analysis from the perspective of the bus line setting, transfer improvements, and the policy to limit cars, respectively.

Based on the extended Huygens–Fresnel integral, the analytical formulae for the cross-spectral density matrix of the partially coherent radially polarized beams diffracted at a circular aperture in turbulent atmosphere are derived. The unapertured and free-space cases can be viewed as the special cases of our general result. By using the degree of coherence formula, the spatial correlation properties of the apertured partially coherent radially polarized beams in turbulent atmosphere are studied. The analyses indicate that the spatial correlation of the apertured partially coherent radially polarized beams are more affected by the atmospheric turbulence with the larger structure constant, the smaller truncation parameter, the larger coherence length, and the farther propagation distance.

The paper studied the relationship between the light spot position and the output voltage in the case of laser spot which is in the four-quadrant (4Q) detector whose shape is circle or elliptic, energy distribution uniform or Gaussian. The study is based on add–subtract algorithm, diagonal algorithm and difference over sum (Δ/∑) algorithm. By using methods of polynomial fitting it can get a simple polynomial expression to enhance measuring speed and the simulation error is given. A method of using Binary Optics Elements (BOE) to shape the laser beam in the 4Q detector to square light spot with uniform intensity distribution is proposed to expand linear measurement range. The simulation result is verified for a circular spot with Gaussian energy distribution.