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Developing environmentally friendly methods to produce hydrogen peroxide (H2O2) has received increasing attention. Photocatalysis has been proved to be a sustainable technology for H2O2 production. Herein, the novel non-metal elements (B, P, and S) doped g-C3N4 tubes (B-CNT, P-CNT, and S-CNT) photocatalysts were obtained via a hydrothermal synthesis followed by thermal polymerization. By adjusting the precursor, the yield of g-C3N4 tubes (CNT) materials has been greatly improved. The as-prepared B-CNT, P-CNT, and S-CNT photocatalysts show an enhanced photocatalytic H2O2 production with the formation rate constants values of 42.31 μM min−1, 24.95 μM min−1, and 24.22 μM min−1, respectively, which is higher than that of bulk CN (16.40 μM min−1). The doped B, P, S elements significantly enhanced the photocatalytic activity by adjusting their electronic structures and promoting the separation of electron-hole carriers. The results have shown great potential for the practical application of CNT photocatalysts.

Oxygen-doped g-C₃N₄ (CN) with carbon vacancies (O–CNC) was synthesized by microwave heating the mixture of melamine–cyanuric acid (MCA) supramolecular aggregates and oxalic acid for only 7 min. The as-synthesized O–CNC shows a mesoporous structure and exhibits a tunable band structure, optimized charge separation, and significantly enhanced two-electron reduction for H₂O₂ production. The photocatalytic H₂O₂ production rate reaches 2008.4 μmol h–¹ g–¹ under simulated sunlight irradiation, which is more than 4 times higher than that of pristine bulk CN. The enhanced photocatalytic performance is attributed to the synergistic effects of the mesoporous structure with a large specific surface area, doped oxygen atoms, and carbon vacancies. These results have provided a facile and efficient way for realizing the practical application of CN in photocatalytic H₂O₂ production.

Graphitic carbon nitride (g-C3N4, CN) has attracted increasing interests in the field of photocatalysis due to its high visible-light-response. However, its photocatalytic activity is still lower for degradation of refractory contaminants such as Cr(VI) and Rhodamine B (RhB) etc. Herein, we report a facile method to synthesize a novel sulfur(S)-doped CN/reduced graphene oxide (rGO) porous nanosheet (S-CN/rGO PNs) via a supramolecular self-assembling followed by a solvothermal treatment. The as-prepared porous S-CN/rGO PNs are stable with high specific surface area ∼188.5 m2g-1 and exhibit a significantly enhanced photocatalytic activity of ∼17-fold and 15-fold higher than that of bulk CN for the degradation of RhB and Cr(VI) under visible light irradiation, respectively. Typically, 50 mL of 15 mg/mL RhB can be degraded within 20 min by 10 mg S-CN/rGO PNs. The mechanism can be explained by the synergistic effect of S doping and porous structure which can effectively reduce the band gap of CN and increase the specific surface area to promote the separation and transfer of photo-generated charge carriers. The results have provided a new way to significantly enhance the photocatalytic activity of g-C3N4 for degradation of refractory contaminants.

Improving the photo-electrochemical water oxidation performance (PEWOP) of pristine TiO2 has been seriously hampered by its poor carrier transport efficiency and sluggish surface water oxidation kinetics. In this work, we prepared a novel IV period transition metal modified carbon layer-coated TiO2 (M-C@TiO2) nanoflower via a facile hydrothermal process followed by annealing at 800 °C. The as-prepared M-C@TiO2 nanoflower is uniform and stable with the size

The flow of cement-based slurry within concentric annular geometry is a major problem of study in the field of engineering, especially regarding the prevention of water ingress in an annulus formed during shaft construction utilizing the artificial freezing technique in China. In this study, an analytical governing equation of motion for the axial flow of an incompressible Newtonian fluid in a long concentric annulus is derived under the condition of high groundwater pressure. A stepwise calculation method is proposed to describe the grouting process based on two injection modes, namely, flow rate control and pressure control. The injection time is divided into a series of time segments; correspondingly, the grouted zone is subdivided into infinitesimal elements. Some key parameters, such as the location, dimension, slurry viscosity, and pressure gradient of each element, can be obtained using the developed MATLAB program. On this basis, the distribution of pressure and slurry viscosity in the grouted zone and the variations in injection pressure at the grouting point and grouting flow rate are determined. Two injection mode cases are investigated to reveal the grout propagation in the concentric annulus. Finally, numerical simulations are conducted and employed to validate and calibrate the calculated results. The results obtained by the present stepwise calculation method show good agreement with the numerical results.

A novel MoS2/TiO2/reduced graphene oxide (MoS2/TiO2/rGO) hybrid photocatalyst was prepared via a two-step hydrothermal process. Where this raspberry-like TiO2 microsphere (300–400 nm) was covered by network-like MoS2 multilayer on the rGO nanosheets. The resulting MoS2/TiO2/rGO hybrid is uniform, chemically stable which can remove 100% Cr(VI) from a 10 mg/L solution within the pH range of 2–5 under simulated sunlight irradiation. Furthermore, it demonstrates excellent reproducibility and stability with a removal rate of 66.7% after seven recycling of Cr(VI) photoreduction which shows a great potential for practical application. The highly efficient photocatalytic activities of this novel hybrid is believed to be ascribed to the enhanced light absorption and photogenerated charge carriers transfer rate of TiO2 due to the hybridization of network-like multilayer MoS2 and rGO nanosheets.

Window operation is an important occupant behavior, and has significant impacts on building energy consumption. Recently, various stochastic and non-stochastic models have been proposed, aiming to describe occupant window behavior based on several influencing factors. However, most of the employed methods are logit regression and Markov chain techniques, and the application of machine learning to model occupants' window behavior is rarely investigated. In addition, most published studies referring to occupants' window behavior have been carried out within European countries, where the influence of outdoor air quality is rarely considered. This study compares different models of occupants’ window behavior, including models based on logistic regression, Markov processes, and an artificial neural network. An artificial neural network model is proposed to explore the application and optimization of an artificial neural network algorithm under a condition of having less samples. Moreover, the outdoor fine inhalable particles ( PM 2.5 ) concentration is considered as an influencing factor for building a window opening model for office buildings during the transition season in China. From this work, it is generally concluded that the PM 2.5 concentration and outdoor humidity should be considered in the modeling of occupant window behavior in Beijing, China. In addition, more true estimations can be obtained from artificial neural network models than from logistic regression models and Markov models. This result demonstrates that the proposed artificial neural network yields a prediction model of office window states with higher accuracy and better interpretability of highly correlated factors as compared to logistic regression models and Markov models. The proposed approaches provide a new and detailed way for engineers and building operators to better understand occupant window behaviors and their impacts on energy use in office buildings.

Ultraflexible, wearable, transparent, and conductive films have recently attracted increasing interest due to their applicability in various electronic devices. In this work, we report a facile, green, and inexpensive approach to preparing flexible hybrid films from graphene nanowalls (GNWs) and ethylene vinyl acetate (EVA) copolymer based on plasma-enhanced chemical vapor deposition (PECVD). PECVD at low temperature (~700 °C) on electrochemically polished Cu foil was found to be an effective method of preparing highly conductive and highly transparent GNWs. The resulting GNWs/EVA hybrid films can be randomly folded, bent, and tailored; they also have a low sheet resistance of ~2.09 kΩ sq−1, a high optical transparency of 67.58% in the UV region, and high wear resistance and ductility, all of which imply that these are highly promising films for use in flexible electronic applications.

In this paper, a novel graphene/Ag nanowires/graphene (G/Ag NWs/G) sandwich film was directly grown on a conventional glass substrate by use of a technique of low temperature (600 °C) plasma-enhanced chemical vapor deposition (PECVD) combined with solvothermal and modified Hummers methods. The as-grown G/Ag NWs/G/glass sandwich film is uniform, smooth, touchable, transparent and conductive with an optical transmission 77.6% and a low sheet resistance ∼10.8 Ω/sq. The top graphene layer exhibits an effective role for improving the touchable and antioxidant properties of Ag NWs, while the bottom graphene layer enhances the binding stability of Ag NWs with substrate. The sheets resistance of G/Ag NWs/G/glass film exposed to the air for 72 h at 95 °C increases from 10.8Ω/sq to 14.6Ω/sq. These indicate a great promising in replacing the expensive and fragile indium tin oxide (ITO) glass and ITO film for touchable transparent electrode applications.

This paper proposed an improved stepwise algorithm to simulate the grout diffusion in a single fracture considering the dynamic grouting parameter boundary condition and the spatial- and t...

Karstic water damage is one of the main disasters that threatens safe production in coal mines. As coal mining in China moves toward deeper strata, deep karst water disasters caused by mining are increasingly common. This paper studies the Jiyang coal mine in Shandong Province, China; conducts an in-depth analysis of the water charging conditions of the Ordovician limestone karst aquifer; determines four evaluation indices of the Ordovician limestone water inrush risk (water yield, water pressure, geological structure complexity and effective aquifuge thickness); and establishes a multifactor model to evaluate the water inrush risk of the Ordovician limestone using multisource information fusion, the water resistance coefficient and the equivalent coefficient. In addition, the floor water inrush risk of the Ordovician limestone during caving mining, strip mining and backfilling mining of the No. 13 coal seam is evaluated in the study area, which is then divided into different zones: a safe zone, a relatively safe zone and a danger zone. According to the evaluation results, the full backfilling mining method with the minimum risk range of water inrush is selected for future mining. Using this method, most of the research area is classified as a safe zone or relatively safe zone, and only a very small area in the south is classified as a danger zone. The threat of Ordovician limestone inrush caused by coal mining is low. The evaluation results of the water inrush risk and optimization of the mining method provide a reference for the prevention and control of mine water damage and can provide guidance for safe coal mining.

Many technical problems are being encountered in roadway tunneling processes, especially at fault bundles and fault-dense zones and in vicinity of the Ordovician carbonate confined aquifers. These complicated tectonic conditions increase the difficulty of water inrush prediction and prevention. This paper takes the roadways tunneling at Jiangzhuang Coal Mine of Shandong Province, China, as a case study. The presence of fault bundles and fault-dense zones reduces the distance between roadway tunneling and the Ordovician carbonate confined aquifer and thus increases the potential risk of water inrush. Based on characteristics of the structure and water bearing formation and hydraulic conductivity in the fault zones, a trinity technique consisting of exploration, grouting, and supporting was proposed to ensure roadway safety tunneling. Underground mine seismic prediction (MSP), underground transient electromagnetic (TEM), underground drilling, numerical simulation evaluations and roadway grouting and supporting were used to understand, reduce, and mitigate the risk of poor stability and water inrush in the roadway tunneling process. Site construction has verified that the fault position was basically consistent with the results from MSP and TEM and drilling. Conclusions from risk evaluation and numerical simulation contributed to the grouting reinforcement and road supporting. Grouting reinforcement of the fracture zone reduced hydraulic conductivity, whereas the reasonable supporting was implemented for the weak part of the surrounding rock, which effectively controlled the roadway deformations. The comprehensive application of the trinity technique provided accurate and defensible geological data for roadway tunneling in this mining area, created favorable conditions for safe and efficient construction, and provided an important reference for research on similar type of roadway construction.

Mine water damage is one of the main disasters threatening mine safety during production. The key to mine water hazard prevention and control is determining the main aquifer characteristics that threaten the mine and the hydraulic connections between aquifers and water diversion channels and proposing appropriate preventive measures. This paper focuses on the 16104 working face of the lower coal group in the Luxi coal mine of Shandong Province. The main water-filled aquifer that threatens the no. 16 coal mine is the Carboniferous no. 14 limestone thin-karst aquifer. Before adopting hydrophobic pressure-lowering measures, it is necessary to determine the water yield characteristics of the no. 14 limestone aquifer, the strength of recharging, and the hydraulic connection with the Ordovician limestone aquifer and to analyze and evaluate the feasibility of dredging. First, various geophysical exploration methods were utilized to comprehensively identify the anomalous water yield areas of the aquifer, which were verified by drilling methods. By combining these results with drilling and geophysical results, appropriate drainage and observation holes were selected. Second, a special water discharge stage and sequence were designed to carry out water discharge testing. By analyzing the change of water discharge and water pressure in dewatering test and the change of conventional ion concentration in water samples, the hydrogeological parameters were obtained, the hydrogeological situation was ascertained and the hydraulic connection with the Ordovician limestone aquifer was determined. The drainage time required for the aquifer to attain a safe water pressure and the amount of hydrophobicity were calculated. Through combination with the obtained hydrogeological parameters, the feasibility of depressurization was analyzed. The results show that the water yield property of the no. 14 limestone aquifer is not high, but the connectivity is good. There is a hydraulic connection between the no. 14 and the Ordovician limestone aquifers, but the connection is weak. The no. 14 limestone aquifer of the entire working surface was drained at a rate of 240 m3/h, indicating that the aquifer has good depressurization properties.

The mining of stratigraphically low coal seams in North China-type coalfields is subject to water inrush from the underlying Ordovician limestone aquifer. The water-inrush coefficient method that is currently used for the evaluation of the water-inrush risk has inherent shortcomings, because it takes into account only the aquifer head pressure and the aquiclude thickness. Therefore, an improved water-inrush coefficient (IWIC) model is proposed. Based on the normalized water-inrush parameter, water-resisting parameter and structural parameter, the IWIC model is established using a linear weighting method. The first-order weights of each parameter are determined by the analytic hierarchy process, and the second-order weights are determined by the trapezoidal fuzzy number technique. Contour maps of the water-inrush risk calculated with the IWIC model are then obtained. The water-inrush risk grades are classified by thresholds derived via the Jenks natural breaks technique. The IWIC model is applied to the Longgu coal mine, as a typical coal mine in China, to evaluate the water-inrush risk of the lower four coal seams (L4CS). The evaluation results show that the risk of water inrush in the L4CS can be divided into five grades: safe, slightly safe, slightly dangerous, dangerous, and extremely dangerous. Overall, the L4CS mining in the Longgu coal mine is seriously threatened by the underlying Ordovician limestone aquifer. As the depth increases, the risk of water inrush increases from the No. 151 to No. 182 coal seams. Among the L4CS, No. 17 and No. 182 have the highest grade of water-inrush risk, and it is proposed that these two coal seams should not be mined to prevent water-inrush accidents.

Grouting techniques have been extensively and effectively implemented to prevent water bursts originating from limestone aquifers in underground mining. Using widely employed grout with time-varying viscosity, promoting the effective propagation of slurry in fractures, especially fractures with narrow apertures, and improving the grouting efficiency (GE) are critical issues that remain unsolved. In this study, an experimental investigation of the fracture GE was conducted considering the dynamically changing injection pressure for viscosity--time-dependent grout using a fracture model constructed from acrylic glass. Three grouting pressure adjustment schemes (periodic-increasing pressure, constant pressure and periodic-reducing pressure) and two narrow hydraulic apertures (200 and 250 μm) were selected for testing. Each trial utilizing the fracture replica was filmed, allowing the advancing slurry to be analyzed versus the propagation distance over time. The measured penetration lengths and fracture GE were then compared with the simulation data. The measured penetration length versus time curves agreed well with the theoretical data. Moreover, the pressure adjustment mode and grout rheology significantly impacted the GE. In general, the periodic increases in pressure reduced the GE, which decreased by 4.16% and 10.19% for the slow- and rapid-growth viscosity grouts (G1 and G2), respectively. However, phase reduction of the pressure considerably enhanced the GE. Relative grouting efficiency (RGE) was increased by 3.18% and 10.08% for G1 and G2, respectively, indicating that a step-by-step reduction in the injection pressure can effectively improve the GE for the remarkable rheological grout during the grouting process. Additionally, the tests suggested that the hydraulic aperture width has an unclear effect on the GE of microfissures.

A new method to directly grow graphene on quartz glass substrate by atmospheric-pressure chemical vapor deposition (CVD) without using any catalyst was developed. The prime feature of this method is to build a vertical-glass model in the quartz tube to significantly increase the collision probability of the carbon precursors and reactive fragments between each other with the glass surface. The growth rate of high-quality graphene on glass remarkably increases compared with the conventional gas flow CVD technique. The optical transmittance and sheet resistance of the graphene glass can be readily adjusted by regulating growth time. When growth time is 35 min, the graphene glass presents an intriguing sheet resistance of about 1.48 kΩ sq−1 at a transmittance of 93.08% and exhibits an excellent hydrophobic performance. The method is simple and scalable, and might stimulate various potential applications of transparent and conductive graphene glass in practical fields.

High-performance hybrid supercapacitor is still hampered by lacking of proper electrode materials of desired nanostructures. However, the hybridization of polyaniline (PANI) on functionalized reduced graphene oxide (FrGO) could form such desired nanostructure with uniform graphene distribution, high carriers density and significantly improved cycling stability and rate capability of PANI. Here we report a facile process for the hybridization of polyaniline nanofibers (PANI NFs) on functionalized reduced graphene oxide (FrGO) films by filtering the hybrid suspension of graphene oxide (GO) and in-situ polymerized PANI NFs followed by hydrothermal treatment to reduce GO and sulfur functionalization of rGO. The as-prepared PANI NFs/FrGO composite films were uniform, flexible and stable with a high specific capacitance of 692.0 F/g at 1 A g−1 and an excellent capacitance retention of 53.5% at 40 A g−1. Furthermore, the assembled all-solid-state supercapacitor using the as-prepared composite films as electrodes exhibited a high capacitance of 324.4 F/g at 1 A g−1 and an energy density ∼16.3 Wh kg−1 at a power density of 300 W kg−1, showing a great promising in the applications for portable power and flexible supercapacitor.

Doping and high specific area are essential to the performance of supercapacitor electrode materials. However, the conventional single doping in two dimensional electrode materials is still unable to get high supercapacitive performance. Here we report a facile hydrothermal process using ammonia as a source of nitrogen (N) and thiourea as a sulfur (S) source to prepare N/S co-doped three dimensional (3D) graphene hydrogel (N/S-3DGH) for supercapacitor electrode application. The as-prepared N/S-3DGH is uniform and stable. The N/S co-doped 3DGH electrode material exhibits a high specific capacity of 1063 Cg-1 at a current density of 1 Ag-1. Even at a density of 20 Ag-1, it can still hold an excellent charge and discharge cycling stability, and with 76% of initial capacity retained after 6000 charge and discharge cycles at a density of 10 Ag-1. Moreover, the all-symmetric solid-state supercapacitor fabricated by N/S-3DGH without any binders owned an energy density of 6.25 Wh kg−1 at a power density of 500 W kg−1 showing very promising applications for portable power and flexible energy storage devices.

A morphology-controllable 0D/1D graphitic carbon nitride (g-C3N4, CN) homojunction (MUCN) was constructed by a facile in-situ thermal polymerization process using the melamine-cyanuric acid supramolecular (MCS) and urea as co-precursor. The as-prepare MUCN is stable with controllable and uniform morphology and exhibits significantly enhanced photocatalytic activities for RhB degradation and H2O2 production. The RhB degradation rate and the H2O2 production are ~37 times and 17 times higher than that of pure CN, respectively. The significantly enhanced photocatalytic performance is attributed to the synergetic effect of energy band controlling and structural coupling in MUCN, which can form the internal driving force to improve the separation efficiency of charge carriers. The results have provided a new effective way for promoting the practical photocatalytic application of CN.

Transition metal layered double hydroxides (TM LDHs) nanosheets have stimulated tremendous research enthusiasm, which is gifted with their tunable chemical compositions, large layer distances and superior electrochemical performance. However, the small number of electroactive sites and the low electrical conductivity have restricted their applications in electrode materials. Herein, we construct a hierarchical Ni3S2/CoFe LDH/Ni foam (Ni3S2/CoFe LDH/NF) hybrid by a facile hydrothermal synthesis followed by an electrodeposition without using any chemical binder. The as-constructed Ni3S2/CoFe LDH/NF exhibits an ultrahigh areal capacitance of 5.08 F cm−2 and an excellent rate capability with a capacitance retention of 73.8% at the high current density of 20 mA cm−2. Furthermore, the constructed asymmetric supercapacitor (ASC) based on the Ni3S2/CoFe LDH/NF anode and the activated carbon (AC) cathode shows both a high power density of 986 W kg−1 and a high energy density of 47.31 Wh kg−1 with high cycling stability of 93.4% initial capacitance after 5000 cycles, demonstrating an enormous potential for the practical application in energy storage devices.

Graphene paper shows a great promise for the electrical energy storage. However, the high stability, purity and specific surface area have become stringent requirements for supercapacitor applications. Finding methods to tackle these problems is rather challenging. Here, we develop a facile method to prepare porous graphene papers with a thickness 0.5 mm by a thermal shock to the layer-structure graphene paper self-assembled on Cu foil under nitrogen flowing. The as-prepared porous graphene paper exhibits a large specific capacitance of 100 F g −1 at the scan rate of 100 mV s −1 with high stability and purity without any residual chemical reagents, showing a promising potential for supercapacitor applications. The high electrochemical properties are mainly attributed to the high-specific area and the improved conductivity of the porous graphene paper performed by the multieffect of reducing, cleaving and expanding to the layer-structure graphene paper by high-energy thermal heating during the thermal shock process. This work paves a pathway to the facile preparation of porous graphene paper for supercapacitor applications.

Quick-setting grout has been widely used in sealing underground excavations to prevent water ingress. Cement and sodium silicate grout (C–S grout), a typical quick-setting slurry, is becoming increasingly more popular in fracture-sealing grouting operations in China because of its short gel time, high early strength and sufficient sealing efficiency. C–S grout contains a cement slurry and sodium silicate solution. During the process of mixing and pouring these two components into the rock fracture, the viscosity of the grout suspension varies over time, which has a considerable influence on the fracture grouting of the C–S slurry. In this study, analytical expressions were derived by implementing the mass conservation equation and radial grouting flow behavior and considering the time-varying slurry viscosity. These governing equations can be used to evaluate the propagation of C–S grout in a planar fracture. Also, the effects of the main factors on the penetration length were investigated, revealing that the rheology of the C–S grout is inherently related to the influence of other parameters, such as injection pressure, injection rate and fracture aperture width, on the fracture grouting. The validation of the proposed approach is examined by comparing the simulation results with the published experimental data. The simulated grouting pressure and pressure distribution in the grouted zone are consistent with experimental observations.

The groundwater potential prediction of sandstone aquifers is an important pre-requisite for the implementation of reasonable and effective measures to prevent mine water inrush disasters. In this study, an attribute recognition model was combined with entropy weighting to predict the groundwater potential of sandstone aquifers in coal mines. Five evaluation indices were selected to predict groundwater potential, such as sandstone thickness, sandstone lithology coefficient, flushing fluid consumption, fracture fractal dimension and fold fractal dimension. On the basis of data analysis, the groundwater potential was classified into four levels. Confidence and improved score criteria were applied to attribute recognition. The main advantages of this model are that it enables both the prediction and quantification of the groundwater potential of sandstone aquifers. The model’s results were compared with those from a comprehensive geographic information system evaluation. The final model results were in good agreement with the observed results, proving that this attribute recognition model is accurate and effective for groundwater potential prediction.

Bi2O2CO3 and reduced graphene (rGO) are considered as promising electrode materials for the applications of supercapacitor due to their high specific capacitance and high cycle property, respectively. However, the poor conductivity of Bi2O2CO3 and low specific capacitance of rGO have restricted their practical application. In this research, we have prepared a novel Bi2O2CO3/rGO composite electrode with a unique flower-like microstructure by a facile hydrothermal synthesis. The as-prepared Bi2O2CO3/rGO composite electrode exhibits a high capacitance of 667 Fg-1 at 1 Ag-1, which is attributed to the short pathways for rapid ionic diffusion provided by the flower-like microstructure and the addition of high-conductive rGO. Furthermore, the asymmetric solid supercapacitor (ASSC) was assembled by using the Bi2O2CO3/rGO and the N/S co-doped rGO electrode, which shows excellent capacitive performance with the capacitance of 68 Fg-1 at 1 Ag-1 and high energy density of 19.85 Wh kg−1 at power density of 1051 W kg−1. In addition, the device exhibits remarkable cycle stability of about 92.6% after 4000 cycles at a current density of 3 Ag-1. The results have provided an effective way for significant improving the capacitance of Bi2O2CO3 electrode and realizing its practical application in ASSC.

Nano-structured Ni3S2 is regarded as one of the most promising supercapacitor (SC) electrode materials due to its unique heazlewoodite phase and high electronic conductivity. However, preparation of Ni3S2 nanostructures with controllable chemical stoichiometry and morphology is still a challenge issue. Herein, we report a novel Ni3S2/3D graphene/nickel foam (Ni3S2/3D G/NF) composite electrode prepared by a chemical vapor deposition (CVD) followed by an electrodeposition. The as-prepared Ni3S2/3D G/NF composite electrode is stable with good chemical stoichiometry, binder-free and exhibits an excellent specific capacitance up to 2585 F/g with current density of 1 A/g,a high capacitance retention rate ~70.68% as the current density increases to 30 A/g, and a capacitance remaining ~88.9% after 5000 cycles of charge and discharge with the current density of 20 A/g. The perfect Ni3S2 heazlewoodite phase and good contact between Ni3S2 and the surface of 3D G/NF are believed to be responsible for the greatly improved conductivity and specific surface area of the as-prepare composite electrode. Our result has provided an effective way to significantly improve the capacitive property of Ni3S2 and shown a great potential for realizing its practical SC applications.

The impact of CO2-driven ocean acidification(OA) on early development and calcification in the sea urchin Strongylocentrotus intermedius cultured in northern Yellow Sea was investigated by comparing fertilization success, early cleavage rate, hatching rate of blastulae, larvae survival rate at 70h post-fertilization, larval morphology and calcification under present natural seawater condition (pH=8.00±0.03) and three laboratory-controlled acidified conditions (OA1, △pH=-0.3units; OA2, △pH=-0.4units; OA3, △pH=-0.5units) projected by IPCC for 2100. Results showed that pH decline had no effect on the overall fertilization, however, with decreased pH, delayed early embryonic cleavage, reduced hatching rate of blastulae and four-armed larvae survival rate at 70h post-fertilization, impaired larval symmetry, shortened larval spicules, and corrosion spicule structure were observed in all OA-treated groups as compared to control, which indicated that CO2-driven OA affected early development and calcification in S. intermedius negatively.

The NiS/reduced graphene (rGO) hybrid has recently attracted increasing interest due to its synthetic effect to improve the conductivity and volume expansion of NiS during charge-discharge cycles as well as the capacitive performance of graphene. However, the preparation of high-performance NiS/rGO hybrid electrode material is still a challenging issue due to its complex multi-step preparation process, which causes low reproducibility, long-time and large-energy consuming. Herein, we report a one-step microwave-hydrothermal preparation of NiS/rGO hybrid electrode material. Compared to the conventional multi-step preparation process, the new method is green without using any chemical surfactant and the preparation time is significantly reduced from several days to only 6 h. The as-prepared NiS/rGO hybrid exhibits a low resistance of ~0.48 Ω, ultrahigh specific capacitance of 1745.67 F g−1 at 1 A g−1 and a high capacity retention of 451.21 F g−1 at 10 A g−1 after 3000 consecutive cycles with high reproducibility. The assembled symmetric solid-state supercapacitor (SCC) based on NiS/rGO hybrid electrode material shows a specific capacitance of 14.20 F g−1, a high energy density of 7.1 Wh kg−1 and a high power density of 1836 W kg−1, demonstrating a great potential for the application in the field of energy storage devices.

The photocatalytic property of graphitic carbon nitride (g-C3N4, CN) photocatalysts is hindered by its low active sites and low photo-generated electron-hole carriers transport rate. Herein, we report a novel CN nanoribbon (CNNR) assembled seaweed-like architecture by microwave synthesis using the melamine-cyanuric acid supramolecular (MCS) as the precursor. The preparation process is facile, fast (

Bi2WO6 (BWO) has recently received extensive interest for water splitting application due to its attractive properties of non-toxicity, high stability and narrow band gap (~2.7 eV). However, the photoelectrochemical (PEC) performance of pure BWO is limited by the inefficiency visible light absorption, and the low electron transport efficiency. Herein we prepared a novel Cu2O nanoparticles/BWO/reduced graphene oxide (Cu2O NPs/BWO/rGO) hybrid by a facile solvothermal synthesis followed by a chemical reduction. The Cu2O NPs and rGO decorate homogeneously on the surface of hydrangea-like BWO. This novel hybrid exhibits a significantly enhanced PEC performance with a ~14 times high photocurrent density than that of pure BWO under simulated sunlight irradiation. This enhancement of the PEC performance is attributed to the significant improvement of coupling Cu2O NPs and rGO, which proves a direct Z-scheme as the main mechanism in Cu2O NPs/BWO, and rGO as a pivotal charge transmission bridge for the efficient photogenerated charge separation, and the increased visible light absorption. The results have provided a new way for the practical water splitting application of BWO.

Development of high-efficiency, low-cost and environmentally friend catalyst for degradation of organic pollutant in water is still a challenge issue. In this research, we prepared a novel Mn-doped Fe3O4 magnetic hollow microsphere/reduced oxide graphene (RGO) hybrid (Mn-Fe3O4/RGO) by a facile solvothermal process followed by a reduction of GO via NaBH4. The as-prepared Mn-Fe3O4/RGO is used as a heterogeneous Photo-Fenton catalyst for degrading Rhodamine B (RhB) and exhibits high efficiency degradation about 96.4% with the low dosage concentration of catalyst 0.2 g L−1 in the presence of H2O2 at the natural pH (~6.5) within 80 min under UV–vis illumination, while the removal efficiency is 91% and 85% at pH 2 and 11, respectively. Furthermore, this novel magnetic Photo-Fenton catalyst remains high degradation efficiency of about 90% after ten cycles and can be easily separated from the solution via an external magnetic field, showing an excellent recyclability, a long-term chemical stability and a great potential for practical wastewater treatment application.

A novel hybrid of Cu nanoparticles/three-dimensional graphene/Ni foam (Cu NPs/3DGr/NiF) was prepared by chemical vapor deposition, followed by a galvanic displacement reaction in Ni- and Cu-ion-containing salt solution through a one-step reaction. The as-prepared Cu NPs/3DGr/NiF hybrid is uniform, stable, recyclable and exhibits an extraordinarily high catalytic efficiency for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) with a reduction rate constant K = 0.056 15 s−1, required time ~30 s and excellent sensing properties for the non-enzymatic amperometric hydrogen peroxide (H2O2) with a linear range ~50 μM–9.65 mM, response time ~3 s, detection limit ~1 μM. The results indicate that the as-prepared Cu NPs/3DGr/NiF hybrid can be used to replace expensive noble metals in catalysis and sensing applications.

High rate of platelet adhesion and limited biocompatibility were regarded as the chief weaknesses of vascular tissue engineering scaffolds. The objective of this research was to overcome these drawbacks by ultilizing coaxial electrospinning to combine CDPS with PLA. CDPS and PLA were located at the inner and external layer respectively so that a “core-sheath” structure was formed. The properties of scaffolds were tested by methods such as mechanical testing, MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay and subcutaneous transplantation. Compared to natural tissues, CDPS/PLA coaxial scaffolds showed excellent biomechanic properties and hemocompatibility so that CDPS owned good potentiality in vascular tissue engineering.

A fine structure inside the canopy of the apple tree determines the light distribution and is one of the important factors affecting the quality and yield of apples. Leaf spatial location (LSL) is the spatial co-ordinates of the petiole–midrib junction point. In this paper, a Trimble TX8 was used to obtain 3D point clouds of the canopy in the flowering, leaf growth stage and stable growth stages of apple tree as the research object. An LSL extraction approach using density-based spatial clustering of applications with noise (DBSCAN) and layers K-mean and median (L-KaM) methods was proposed. Firstly, the DBSCAN clustering method based on adaptive parameters is used to separate single leaves from branches. Secondly, the same point cloud is sliced into layers, and the L-KaM method is used to fit the branch center line. Finally, the Euclidean distance of each point between the single leaf and the center line is determined, and the point with the smallest Euclidean distance is the LSL point. Field experiments show that the DBSCAN-L-KaM method proposed in this study is suitable for LSL extraction during the leaf growth and stable growth stages. The maximum Euclidean distance between the manual measurements’ actual LSL value and the values automatically extracted (ELD_MaA) was less than 9 mm, and the average ELD_MaA was 1.41 mm. The average extraction rate of tall spindle training system apple trees and free spindle training system apple trees were 89.90% and 51.75%, respectively. Using the method in this paper, we obtain the whole apple tree (3-year-old) LSL value in about 2.5–3 h. The method provides theoretical basis and systemic support for the analysis of the light-intensity distribution of apple trees and the internal structure details of fruit trees.