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Two kinds of Fe/amorphous carbon (a-C) submicron fibers were prepared by electrospinning using polyvinylpyrrolidone (PVP) and polyacrylonitrile (PAN) as precursor polymer, followed by carbonization under the same conditions. Contributed to the different reaction mechanisms during the annealing process, different phases namely graphite carbon (g-C) and Fe4N formed at the interface between the Fe nanoparticles and the a-C matrix. Electromagnetic absorption properties have shown that the Fe@Fe4N submicron fibers have superior absorption performance than the Fe@g-C ones. The minimal reflection loss (RL) value of the former is − 39.8 dB at 5.4 GHz with the absorber thickness of 5.0 mm, and the effective absorption bandwidth (RL ≤ − 10 dB) can reach 5.0 GHz when the absorber thickness is 2.5 mm. By contrast, the Fe@g-C submicron fibers have little absorption. The attenuation constant, impedance matching coefficient, complex permittivity and complex permeability were investigated in detail. The microstructure and composition were explored various superior tools. The results revealed that the interface Fe4N has a critical role in affecting the magnetic loss and dielectric loss, which brings better impedance matching and relatively low dielectric loss. Therefore, the Fe@Fe4N submicron fibers have excellent microwave absorbing properties.

A temperature control curtain can effectively mitigate the negative effect of outflow temperature on the river eco-environment downstream. To investigate the response of outflow temperature to influence factors (i.e., installation position of temperature control curtain, submerged depth, temperature distribution, and outflow discharge), experiments were conducted in a nonlinearly stratified fluid. The important degree of influence factors was determined by entropy weight method. The results indicated that the effect extent of influence factors on the outflow temperature was temperature distribution, submerged depth, outflow discharge, and installation position in turn. The installation position had little effect on the outflow temperature. Increasing the outflow discharge could withdraw more warm water near the surface and increase the outflow temperature. The outflow temperature also rose with decreasing submerged depth, and more warm water above the temperature control curtain level tended to be extracted when the submerged depth was enough. Although the outflow temperature increased, its variation amplitude depended on the temperature gradient of temperature distribution and was not affected by the structural form of selective withdrawal. From the point of operation management, the minimum submerged depth was determined using sensitivity analysis to obtain maximum improvement of outflow temperature.

Alanine aminotransferase (ALT) levels between 1 and 2 times the upper limit of normal (ULN) are common in patients with chronic hepatitis B (CHB) infection. There are few clinical studies focused on this group of patients because of the poorer treatment outcomes compared to those with more than 2 × ULN ALT level. However, treatments are necessary to reduce liver damage for patients with minimally elevated ALT levels. And biomarkers are needed in predicting the treatment response. In this study, a total of 106 patients with CHB were enrolled and treated with entecavir, telbivudine or tenofovir disoproxil fumarate. Liver stiffness was measured by transient elastography, and quantitative levels of hepatitis B core antibody (HBcAb) were detected by ELISA. At week 96, 31 (29.25%) patients achieved hepatitis B e antigen (HBeAg) seroconversion. Notably, baseline HBcAb levels and liver stiffness measurements (LSM) were higher in patients who achieved HBeAg seroconversion. The multivariate analysis showed that the baseline HBcAb levels and LSM were independent predictors for HBeAg seroconversion. The area under receiver operating characteristic curve of baseline HBcAb, LSM and the combination of them for HBeAg seroconversion was 0.714, 0.720 and 0.717, respectively. In addition, we discovered that the patients with baseline HBcAb levels ≥ 4.15 log10 IU/mL and LSM ≥ 9.85 kPa had higher rates of HBeAg seroconversion. Therefore, the measurement of HBcAb and liver stiffness might be good approaches for the optimization of antiviral therapy for HBeAg-positive CHB patients with minimally elevated ALT levels.

Carbon films prepared by polyimide (PI) films treated under 1500°C exhibit favorable thermal conductivity. However, the bonds of carbon films will fracture and recombine which will cause shrinking and forming defects. The flexibility of the carbon films will be greatly reduced, and then affect the application of the carbon films in the field of thermal conduction. When the films prepared by the graphene oxide/polyimide (GO/PI) composite films and the reduced graphene oxide/polyimide (rGO/PI) composite films, respectively, rGO and GO can fill the defects, then increasing the flexibility of the carbon films and inducing the carbonation process. Because of the high thermal conductivity and the six-membered ring structure of rGO and GO, the carbonization temperature will decrease and save costs. When the composite films treated under 1500°C, the thermal conductivity increases with the content of rGO and GO. There are connections between PI and graphene. As the amount of rGO and GO increases, the strong interactions between the rGO or GO and PI lead to contact that enhances its thermal conductivity. However, the rGO and GO have different effects on the films flexibility and thermal conductivity and the differences will be described in the article.

Hybrid energy storage system (HESS) consisted of battery and supercapacitor plays an essential role in supporting the normal operation of pulse load in vessel integrated power system (IPS) as well as improving power quality. However, due to the unique properties of the pulse load and diversified operations of the vessel, such advanced power system architectures tend to face greater challenges in optimal power allocation. In order to address the power allocation challenges, a novel optimized state-of-charge (SOC) feedback based energy management strategy is proposed for HESS in IPS to restrain the DC bus voltage fluctuation in this paper. Firstly, considering the operating characteristics of the pulse load in IPS, the optimized SOC of the HESS is introduced to the low-pass filter (LPF) with variable time constant to split the power in the HESS. Secondly, SOC recovery control of the supercapacitor is introduced to the LPF to optimize the size of the HESS as well as prolong the lifetime of the battery. Also, the enforced intervention is introduced to avoid the opposite state of the HESS. The proposed strategy can make full use of the HESS complementary characteristics to compensate the pulse load and optimize the HESS. Finally, the simulation conducted in PSCAD demonstrates the effectiveness of the strategy proposed in pulse load compensation as well as HESS optimization.

Efficient inverted (p-i-n) type CsPbI

Cardioembolic stroke (CS) is the most common type of ischemic stroke in the clinic, leading to high morbidity and mortality worldwide. Although many studies have been conducted, the molecular mechanism underlying CS has not been fully grasped. This study was aimed at exploring the molecular mechanism of CS using comprehensive bioinformatics analysis and providing new insights into the pathophysiology of CS. We downloaded the public datasets GSE58294 and GSE16561. Differentially expressed genes (DEGs) were screened via the limma package using R software. CIBERSORT was used to estimate the proportions of 22 immune cells based on the gene expression profiling of CS patients. Using weighted gene correlation network analysis (WGCNA) to cluster the genes into different modules and detect relationships between modules and immune cell types, hub genes were identified based on the intersection of the protein-protein interaction (PPI) network analysis and WGCNA, and their clinical significance was then verified using another independent dataset GSE16561. Totally, 319 genes were identified as DEGs and 5413 genes were clustered into nine modules using WGCNA. The blue module, with the highest correlation coefficient, was identified as the key module associated with stroke, neutrophils, and B cells naïve. Based on the PPI analysis and WGCNA, five genes (MCEMP1, CLEC4D, GPR97, TSPAN14, and FPR2) were identified as hub genes. Correlation analysis indicated that hub genes had general association with infiltration-related immune cells. ROC analysis also showed they had potential clinical significance. The results were verified using another dataset, which were consistent with our analysis. Five crucial genes determined using integrative bioinformatics analysis might play significant roles in the pathophysiological mechanism in CS and be potential targets for pharmaceutic therapies.

School bullying has attracted worldwide attention for its adverse outcomes; however, there is still a lack of research among college students. The aim of this study was to investigate the prevalence of school bullying victimization and the associated factors among Chinese college students.8098 Chinese college students from two universities in Hunan province were recruited in this cross-sectional study, and data on participants' demographic information, bullying history, suicidal behaviors, anxiety (Self-Rating Anxiety Scale) and depression (Self-reporting Depression Scale) were collected. Binary logistic regression was used to analyze the independent correlates of school bullying.The prevalence of school bullying was 8.03% in our study. Gender (OR,0.792;95%CI[0.660,0.950]; p = 0.012); depression (OR,1.979; 95%CI[1.359,2.883]; p 0.001); anxiety (OR,1.996; 95%CI[1.388, 2.869]; p 0.001); suicidal ideation (OR,1.353;95%CI[1.087,1.684]; p = 0.007); suicide attempts (OR,1.772;95%CI[1.306,2.403]; p 0.001); family income between 30,000 and 70,000/year (yuan) (OR,0.763;95% CI[0.627,0.929]; p = 0.007) and family income more than 70,000/year (yuan) (OR,0.578;95%CI[0.461,0.725]; p 0.001) were independent correlates of school bullying. The bullying score was positively correlated with physical or mental disorder history, family history of mental disorder, suicidal ideation, suicide plans, suicide attempts, anxiety, depression, smoking and drinking alcohol (all p 0.05), and negatively correlated with right-handedness, good relationship with parents and family income (all p 0.05).No causal relationship could be drawn due to the cross-sectional design.School bullying is quite common among college students. In order to improve students' mental health and prevent suicide, we should pay attention to the negative effects of bullying victimization such as depression, anxiety, suicidal behaviors and so on, apart from putting in place anti-bullying interventions.

The core-shell hierarchical mesoporous titanium dioxides with situ nitrogen dopen carbon and the stable architecture are synthesized by a feasible route, basing on the sol-gel, freeze-drying and calcination process. Nitrogen doped carbon is synergistically compounded with nano-TiO2 to fabricate the hybrid composite (C-N@MP-TiO2), which has high surface area of 318 m2 g−1 and large average pore size of 6.8 nm. This corresponding anode consisted of the hybrid composite exhibits superior specific capacity, rate capability, and long cycling stability. Also, the initial discharge capacity is up to 360 mAh g−1 at the current density of 0.1 A g−1 with the good capacity retention of 97% after 350 circles. The excellent rate performance presents the capacity of 173.6 mAh g−1 at the current density of 5 A g−1. Moreover, the large current reversible capacity (20 A g−1) can reach 172.2 mAh g−1 with long-term cycling stability over 500 cycles. Therefore, the superior electrochemical performances are attributed to the stable core-shell mesoporous structure and in-situ nitrogen doped carbon, which is not only improve the electron transport and lithium ion diffusion, but also facilitate the immersion of electrolyte.

In order to investigate how to enhance the teeth fracture resistance after the post and core treatment, an in vitro study was conducted to measure the fracture resistance of endodontically treated teeth restored with cast post and core with two kinds of surface treatment technology and acid etching preparation on the dentinal surface. Sixty-four recently extracted human single-rooted first premolars were endodontically treated and sectioned approximately 1.5 mm above the cementoenamel junction to remove the coronal portion. Each specimen received a cast post, core build-up and a metal alloy crown restoration. All teeth were randomly divided into the smooth surface post, core repair group, the sand blasting surface post, and core repair group, each group was divided into 10 s, 30 s, 60 s acid corrosion treatment group and control group. In acid test groups, an acid etching solution was applied for 10, 30 and 60 seconds, respectively, to the root canal wall surface. Each specimen was embedded in acrylic resin block and tested in an electronic universal testing machine. Fracture loads results showed that canal acid etching could increase teeth fracture resistance strength both in smooth groups and sandblasting group, and achieved the best effect when acid etching for 30 s. Sand spray treatment on the surface of the cast metal post can improve the flexural strength of the teeth after postcrown restoration. Acid etching on the root canal wall surfaces and sand spray treatment on the surface of the cast metal post can improve the flexural strength of the root after post-crown restoration. Therefore, these two methods could be used to strengthen the tooth fracture resistance, and maintain the long-term therapeutic effect of cast post and core restoration.

The metabolism of starch, the major resource of carbohydrates and an essential determinant of plant fitness in plants, often exhibits plasticity in response to challenging environmental conditions. Previous study of leaf starch turnover under abiotic stresses documented conflicting patterns. To understand this discrepancy and examine the process in more detail, we grew Arabidopsis seedlings under a series of typical stress conditions, observed and quantified leaf starch content at different time. By electron microscope, iodine staining and starch quantification, we confirm that short-term (8 h) stress treatments, such as osmotic stress, high salinity, caused rapid starch decrease during the night while long-term (56 h) stresses increased starch content significantly. Exogenous abscisic acid (ABA) induced similar effects to the abiotic stresses. Comparison of the starch content in wild type (WT) and the ABA receptor quadruple mutant pyr1;pyl1;pyl2;pyl4 suggests that the stress-induced starch turnover change is also mediated by ABA-independent pathways. In addition, more energy supply caused severer growth defect under stress conditions. And the transcription levels of both starch biosynthesis enzymes (APL1 and APL3) and starch degradation enzymes (SEX1, SEX4, BAM1 and BAM3) exhibited differential increase under long-term stresses. Taken together, our data strongly suggest that young seedlings adapt to stress by retaining starch and retarding growth through both ABA-dependent and -independent pathways.

Selective withdrawal is commonly implemented in nonlinearly stratified ambient, which typically has stratified ambient conditions, for purposes of controlling quality. A floating intake is applied as an effective facility of selective withdrawal. However, the outflow dynamics of a floating intake in a nonlinearly stratified ambient have been disregarded, which has a significant effect on the outflow water quality of a reservoir. Experiments were conducted to investigate the effect of thermal stratification on the flow characteristics using particle image velocimetry at three temperature distributions (no stratification, weak stratification and strong stratification). The flow fields upstream of the floating intake showed that the withdrawal layer was formed inhibited by the thermal stratification. And strong stratification produced the thinner withdrawal layer thickness, leading to a larger nonuniform coefficient of the velocity profile. To quantitatively describe the velocity profiles, formulas of dimensionless velocity profiles were proposed. The flow developments were analysed, and the virtual control points located 0.56d above the floating intake (where d is the straight pipe diameter of the floating intake) were obtained. The positions of virtual control points mainly depended on the withdrawal discharge. The decay rate of the velocity along the horizontal line passing through the virtual control point was inversely proportional to the stratification intensity.

Artificial substrates (ASs) and floating treatment wetlands (FTWs) have been widely used in the treatment of polluted surface water. In fact, periphyton on ASs functions in nutrient removal, while the plant-periphyton complex functions in FTWs. However, the nutrient removal performance of the periphyton on ASs and the plant-periphyton complex in FTWs has not been systematically compared. Thus, ASs and FTWs were established in a mesocosm experiment to compare nitrogen and phosphorus removal between the two ecological treatment techniques. The results showed that the total nitrogen removal efficiency was 60.4% in the AS treatments and 65.3% in the FTWs, while the total phosphorus removal efficiency was 83.7% in the AS treatments and 39.45% in the FTWs. Periphyton on the ASs absorbed 2.5 g N m−2 and 0.85 g P m−2, accounting for 20.8% of the N removal and 18.7% of the P removal. Sedimentation contributed to 71.3% of the N removal and 56.1% of the P removal in the AS treatments. For the plant-periphyton complex in the FTWs, 25.1% of the N and 53.0% of the P accumulated in plant tissue. Most of the reduced N (47.1%) was removed by other pathways, which was likely the effect of periphyton attached on plant roots and floating rafts. The nutrient removal efficiencies and pathways of AS and FTW treatments showed different characteristics, providing a reference for the selection of treatment measures for polluted surface water remediation.

Streptococcus suis is a major swine pathogen and an important zoonotic agent worldwide. At least nine serotypes can infect human so far. Although 29 serotypes (1-19, 21, 23-25, 27-31 and 1/2) strains are considered as authentic S. suis, a novel variant serotype Chz and strains carrying 20 novel capsular polysaccharide loci (NCL) have been identified recently. However, information about pathogenic and antimicrobial resistance characteristics of strains carrying NCLs is still unavailable. In this study, we identified six new NCLs (designated as NCL21-26) from 35 non-typeable S. suis strains by agglutination tests and whole genome sequencing analysis. Further analysis of the genetic context of NCL25 and NCL26 showed a mosaic structure of the capsular polysaccharide loci. NCL25 exhibited considerable similarity to that of serotypes 10 and 11, and NCL26 shared similarity to that of serotype 9 and NCL4. Antimicrobial susceptibility testing demonstrated that strains carrying NCL21-26 were all resistant to clindamycin, lincomycin, erythromycin, tilmicosin and tetracycline. Animal infection experiments showed that the virulence of NCL26 strain NJ1112 isolated from a disease pig was similar to that of S. suis serotype 2 virulent strain SC070731 in both zebrafish and mouse infection models, highlighting the necessity for surveillance of strains belonging to NCL26. We also developed a multiplex PCR assay to detect NCL21-26 strains. Our findings expand the views of genetic diversity of S. suis capsular polysaccharide loci and S. suis pathogenic characteristic.

Background Traditional intravesical instillation treatment in bladder cancer has limited efficacy, which results in a high frequency of recurrence. Purpose The aim of this study was to report on an epirubicin (EPI)-loaded magnetic multi-walled carbon nanotube (mMWCNTs-EPI) system for intravesical instillation in place of the current formulation. Methods The mMWCNTs-EPI system was formulated with carboxylated MWCNTs, Fe3O4 magnetic nanoparticles, and EPI. Features and antitumor activity of the system were investigated. Results Under the effect of external magnets, the mMWCNTs-EPI system showed sustained release and prolonged retention behavior and better antitumor activity than free EPI. The mMWCNTs-EPI system had higher efficiency in enhancing cytotoxicity and inhibiting proliferation in vitro and in vivo than free EPI. Our studies also revealed the atoxic nature of mMWCNTs. Conclusion These findings suggested that mMWCNTs are effective intravesical instillation agents with great potential for clinical application.

Background Minimally invasive facial cosmetic surgery (MIFCS) is becoming more and more popular and acceptable in Chinese young people, and it influences people in many aspects. However, there is little research on the associations between MIFCS and psychopathology in Chinese college students. The purpose of this study was to identify the prevalence of MIFCS and its associated factors among Chinese college students. Methods A cross-sectional design was applied in this study. A total of 8089 students completed an online questionnaire on demographic data, depressive symptoms (Self-Rating Depression Scale), anxiety symptoms (Self-Rating Anxiety Scale) and MIFCS. Logistic regression was used to identify independent factors associated with MIFCS. Results The prevalence of MIFCS in Chinese college students was 2.7% (221/8098). Students with MIFCS were more likely to be from urban areas, from a single child household, experience depression or anxiety and have a history of smoking (all p Conclusions Minimally invasive facial cosmetic surgery (MIFCS) is very common in Chinese college students, indicating the importance of paying attention to MIFCS. This study provides valuable evidence for college counselors and doctors in the cosmetic department to provide better and healthier services to students who undergo MIFCS, especially those with depressive symptoms.

Background: Minimally invasive facial cosmetic surgery (MIFCS) is becoming more and more popular and acceptable in Chinese young people, and it influences people in many aspects. However, there is little research on the associations between MIFCS and psychopathology in Chinese college students. The purpose of this study was to identify the prevalence of MIFCS and its clinical correlates among Chinese college students. Methods: A cross-sectional design was applied in this study. A total of 8089 students completed an online questionnaire on demographic data, depression (Self-Rating Depression Scale), anxiety (Self-Rating Anxiety Scale) and MIFCS. Logistic regression was used to identify independent factors associated with MIFCS. Findings: The prevalence of MIFCS in Chinese college students was 2·7% (221/8098). Students with MIFCS were more likely to be from urban areas, from a single child household, experience depression or anxiety and have a history of smoking (all p

Hybrid battery energy storage system (HBESS) consists of high power density battery and high energy density battery will have a bright future in special isolated DC microgrid conditions such as the all-electric ships and all-electric airplanes, which have strict limitation on storage capacity and size. In this study, a new decentralised control strategy based on mixed droop is proposed to HBESSs with considering the batteries. In decentralised control strategy, conventional V–I droop controller is utilised to high energy density battery to mainly supply the steady power, I–V droop controller is utilised to high power density battery to respond to power change and supply a few steady power. In addition, dynamical state-of-charge (SoC) regulation algorithm is utilised to reassign the battery power according to their own SoC. The power coordination of the high energy density batteries and high discharge rate batteries is achieved by adjusting the values virtual impedance and reference input voltage. Case study shows that the proposed control strategy is flexible and efficient.

Aiming at the problems in positioning accuracy of stereo vision guided robots. Here, we firstly calibrated two cameras separately and calculated the relative position-attitude between the two cameras. A more accurate relative position-attitude and the distortion parameters between the two cameras of each image were obtained by optimizing the projection error of the marks via Bundle Adjustment (BA). Then, we identified the world coordinates of the marker point by using the triangulation principle of the parallel binocular camera. According to the position-and-pose parameters of each image that captured by left camera and the data of corresponding robot end, Tsai hand-eye calibration method was applied to work out the relative position-and-attitude of the end of the robot to the left camera. Hence, the robot could be accurately guided to operate with the precise position of target point. The experimental result suggests that the algorithm in this study is favorably reasonable and can accurately to guide robot positioning.

Frequent changes between inflow and outflow operations pose significant challenges in the design of bidirectional flow passage components with high efficiency and stability. In this study, hydraulic optimization of the inlet/outlet diffusion segment of a pumped storage power station was performed. First, a 3D-optimization platform was established for the inlet/outlet diffusion segment, and consists of parametric modelling, automatic mesh generation, CFD numerical calculation, and an optimization strategy. Three objective functions; the head loss, velocity uneven distribution, and discharge uneven distribution; were adopted to evaluate the overall performance of the inlet/outlet diffusion segment. Both dual- and triple-objective optimizations were adopted to optimize the shape of the inlet/outlet diffusion segment, the response surface methodology (RSM) was used to generate approximate functions relating to the objectives and design parameters, and the non-dominated sorting genetic algorithm (NSGA-II) was selected to conduct the optimizations. The objective of the present study was to use a numerical optimization method to determine the optimal inlet/outlet structure configurations yielding better hydraulic performance with bidirectional flow conditions. The results show that with triple-objective optimization, the head loss decreased by 2.71%, velocity uneven distribution decreased by 21.05%, and discharge uneven distribution decreased by 2.24%.

Understanding flood event-related risk in an interconnected river–lake system (IRLS) is a prerequisite for developing water resource management strategies and enhancing disaster resilience. Previous flood event-related risk assessments either hardly consider the context in which water diversion encounters flood events or hardly consider the physical process, stochastic analysis and multivariate interactions of flood event characteristics simultaneously, thereby resulting in a less reliable assessment of flood event-related risk. To resolve this limitation, a copula-coupled hydrodynamic risk assessment model (CHRAM) is proposed to characterize the physical, multivariate, and stochastic nature of risk, improving the accuracy of risk assessment. In this study, CHRAM is capable of accurately quantifying flood event-related risks (i.e., flood risk and ecological risk) of the Nansi Lake Basin in the flood season under the operation of the eastern route of the South-to-North Water Diversion Project in China. Our findings revealed that the total flood volume (Rsum) and duration (Td) of flood events were significantly sensitive characteristic indexes for flood risk and ecological risk. In addition, the security domains of flood risk (Rsum

The inlet/outlet is an important part of a water conveyance system in a pumped storage power station (PSPS). Its hydraulic characteristics are directly related to the operation and economic benefit of the PSPS. Frequent changes between inflow and outflow operations pose significant challenges in the design of the inlet/outlet diffusion segment shape. In this study, an effective optimization method, including three-dimensional parametric modelling, computational fluid dynamics and a genetic algorithm, is introduced and coupled to the design of the diffusion segment shape. The hydraulic characteristics of bi-directional flow, including the head loss, velocity uneven distribution and uneven discharge distribution, are selected as the objective function in the optimization method. Using this method, the recommended shape of the inlet/outlet is studied and its hydraulic characteristics are discussed. The results indicate that the optimized inlet/outlet has better performance.

Climate change has an indirect effect on water quality in freshwater ecosystems, but it is difficult to assess the contribution of climate change to the complex system. This study explored to what extent climatic indicators (air temperature, wind speed, and rainfall) influence nutrients and oxygen levels in a shallow reservoir, Yuqiao Reservoir, China. The study comprises three parts—describing the temporal trends of climatic indicators and water quality parameters during the period 1992–2011, analyzing the potential impacts of climate on water quality, and finally developing a quantitative assessment to evaluate how climatic factors govern nutrient levels in the reservoir. Our analyses showed that the reservoir experienced substantial cold periods (1992–2001) followed by a warm period (2002–2011). The results showed that increasing air temperature in spring, autumn, and winter and increasing annual wind speed decrease total phosphorus (TP) concentration in the reservoir in spring, summer, and winter. According to the quantitative assessment, the increase in air temperature in spring and winter had a larger contribution to the decrease in TP concentration (47.2 and 64.1%), compared with the influence from decreased wind speed and rainfall. The field data suggest that nutrients decline due to enhanced uptake by macrophytes in years when spring was warmer and the macrophytes started to grow earlier in the season. The increasing wind speed and air temperature in spring also significantly contribute to the increase in dissolved oxygen concentration. This study helps managers to foresee how potential future climate change might influence water quality in similar lake ecosystems.

In this paper, we designed a facile method to prepare nitrogen doped CNT (N-CNT), boron-doped CNT (B-CNT) and nitrogen, boron co-doped CNT (N,B-CNT) catalysts for oxygen reduction. The microstructures of the catalysts were characterized by Raman spectroscopy, X-ray diffraction (XRD), transmission electron microscope (TEM), and X-ray photoelectron spectroscopy (XPS). The results clearly showed the successful doping of nitrogen or/and boron. The cyclic voltammetry (CV), Tafel, linear scanning voltammetry (LSV) tests confirmed that the onset potentials and peak current intensities of oxygen reduction increased in the sequence of pure CNT

To explore the correlations among water quality parameters, suspended solids (SS) and total dissolved solids (TDS) with meteorological factors in a shallow reservoir in China, the long-term variations of water quality were considered. A non-parametric regression method, generalized additive models (GAM), was used to analyse the correlations among eleven physicochemical and biological parameters as well as three meteorological factors (wind speed, rainfall and solar radiation) which we collected from 2000 to 2011. The results indicate that the three meteorological factors may have positive effects on SS. Moreover, statistically significant correlations between many water quality parameters and SS or TDS were exhibited seasonally. The correlations between electrical conductivity (EC) and SS were opposite to correlations between EC and TDS. This finding reveals that TDS have a positive impact on EC, while EC negatively affects SS. The results indicated that many parameters, such as total nitrogen, total phosphorus, biological oxygen demand (BOD) and chemical oxygen demand (COD), were related to SS due to the adsorption of SS. Moreover, both positive and negative correlations between COD and TDS were observed in this freshwater reservoir. The positive correlation between chlorophyll a and SS suggested that the change of SS concentration in autumn was caused by the growth of algae. Meanwhile, significant correlations between SS and meteorological factors were also observed, indicating that meteorological factors had effects on SS dynamics. This study provides useful information regarding the correlations among water quality parameters, SS and TDS with meteorological factors in a freshwater reservoir.

Large shallow reservoirs control flooding, supply water, and protect the ecological environment, which are vital functions for societal development. As the largest artificial plain reservoir in China, Suyahu Reservoir is suffering from significant sedimentation and water quality deterioration in recent years. A three-dimensional (3-D) hydrodynamic and water quality model was developed based on the Environmental Fluid Dynamic Code (EFDC). The model was applied to seven scenarios for evaluating the response of in-reservoir hydrodynamics and water quality to the restoration measures, including expansion and sediment dredging project, external load reduction, and inflow regulation. The results show that: (1) the expansion and sediment dredging project has no notable improvement on the water quality of the reservoir, (2) the external load reduction can significantly improve the water quality of the reservoir, and (3) the optimal inflow condition occurred when the flows of Ru River&rsquo, s two inlets were evenly distributed, and the hydrodynamics and water quality were best improved. Moreover, the increasing water exchange rate could not cause the same water quality improvement, showing that it may be unreliable to evaluate the effects of restoration measures using a single indicator. This study can provide useful information for developing and implementing effective restoration measures in large shallow reservoirs.

The dual active bridge (DAB) DC-DC converter plays an important role in the ship integrated power system energy storage device. To improve its dynamic characteristics in the case of fluctuations at the input and output ends, a new control strategy is proposed. The strategy is based on direct power control (DPC) which obtains the transmission power deduced from the single phase shift control and the virtual current is introduced to amend it. This strategy eliminates the need for device parameters to participate in the control and only samples the input and output voltages which significantly simplifies the controller structure and improves its compatibility. The proposed strategy and traditional PI control are compared and simulated through the simulation model built in PSCAD. The results show that the proposed strategy can effectively improve the dynamic performance of the DAB DC-DC converter.

The energy management system (EMS) is an important part of vessel integrated power system (IPS). Its performance significantly effects the overall performance of the IPS. The EMS usually adopts a hybrid information network structure featured by a hierarchical topology and adoption of multiple network protocols. In this paper, a double-layer hybrid information network consisting of Ethernet and CAN bus is taken as the research object. In OPNET Modeler, node models of CAN bus terminal, CAN subnet controller, Ethernet data module and Ethernet controller are built, and the simulation model of the hybrid EMS network is constructed. Transmission delay of data packets is analyzed under different network topologies and circumstances. The models are validated through simulation results, and the proposed modeling method can provide theoretical basis and simulative method for the design and implementation of future IPS EMS information network.

Modelling is a useful tool for comprehensively describing the processes occurring in floating treatment wetlands (FTWs). However, temperature effects and phosphorus dynamics are not considered in the current FTW models. Therefore, a process-based model comprised of a plant growth submodel, a nitrogen dynamic submodel and a phosphorus dynamic submodel was developed to understand the complicated processes occurring in FTWs. The model was fully calibrated using a mesocosm FTW system operated for 168 days. Global sensitivity analysis revealed that nitrogen removal performance was predominantly sensitive to parameters representing plant characteristics and microbial activity. Because of the high concentration of organic matter, mineralization and sedimentation played important roles in nitrogen and phosphorus removal. In addition, the coprecipitation rate of phosphate also had a significant influence on phosphorus removal performance. When further investigation was applied to understand the behavior of the model, the ratio of nitrogen to phosphorus in plant tissue was found to be an indicator of the nutrient limitation in the water column. Furthermore, the model illustrated that both FTW operating conditions and plant characteristic parameters exerted an important influence on nitrogen removal and plant uptake contribution. Therefore, the selection of appropriate operating conditions and plant species can achieve high nutrients removal and make effective use of plants in FTWs. The model provides a useful tool for assessing the nutrients removal performance of FTWs and for evaluating strategies for them in design and operation.

A piecewise linearized power distribution control strategy of Hybrid Energy Storage System (HESS) for the DC vessel microgrid is proposed in this paper. It not only can stabilize the DC bus voltage well but also can optimize the charge/discharge operation of storage units according to their current state-of-charge (SOC) level. The high power density energy storages (e.g. supercapacitor) response quickly to compensate the instantaneous load variation and keep the bus voltage stabilization, the high energy density energy storages (e.g. lithium battery) supply the continuous energy, moreover, the charge/discharge power of the lithium battery is closely related to the current SOC level of the supercapacitor. Simulation results indicate that the control strategy can automatically adjust the working state and output of the supercapacitor and lithium battery, and maintain the DC bus voltage within a reasonable range when the load demand suddenly change.

The lateral inlet/outlet plays a critical role in the connecting tunnels of a water delivery system in a pumped hydroelectric storage (PHES). Therefore, the shape of the inlet/outlet was improved through computational fluid dynamics (CFD) optimization based on optimal surrogate models. The CFD method applied in this paper was validated by a physical experiment that was carefully designed to meet bidirectional flow requirements. To determine a good compromise between the generation and pump mode, reasonable weights were defined to better evaluate the overall performance. In order to find suitable surrogate models to improve the optimization process, the best suited surrogate models were identified by an optimal model selection method. The optimal configurations of the surrogate model for the head loss and the velocity distribution coefficient were the Kriging model with a Gaussian kernel and the Kriging model with an Exponential kernel, respectively. Finally, a multi-objective surrogate-based optimization method was used to determine the optimum design. The overall head loss coefficient and velocity distribution coefficients were 0.248 and 1.416. Compared with the original shape, the coefficients decrease by 6.42% and 40.28%, respectively. The methods and findings of this work may provide practical guidelines for designers and researchers.

Background Traditional intravesical instillation treatment in bladder cancer has limited efficacy, which results in a high frequency of recurrence. Purpose The aim of this study was to report on an epirubicin (EPI)-loaded magnetic multi-walled carbon nanotube (mMWCNTs-EPI) system for intravesical instillation in place of the current formulation. Methods The mMWCNTs-EPI system was formulated with carboxylated MWCNTs, Fe3O4 magnetic nanoparticles, and EPI. Features and antitumor activity of the system were investigated. Results Under the effect of external magnets, the mMWCNTs-EPI system showed sustained release and prolonged retention behavior and better antitumor activity than free EPI. The mMWCNTs-EPI system had higher efficiency in enhancing cytotoxicity and inhibiting proliferation in vitro and in vivo than free EPI. Our studies also revealed the atoxic nature of mMWCNTs. Conclusion These findings suggested that mMWCNTs are effective intravesical instillation agents with great potential for clinical application.

The network reconfiguration of a vessel power system (VPS) is one of the most important approaches to restore its power supply and improve its survivability. The current research on the reconfiguration mainly focuses on the selection and optimisation of recovery paths, with little consideration of the influence of recovery time series. The limited capacity of the VPS, many loads of the motor load and large starting current have a great impact on the electric-energy quality of the power system. Therefore, the different recovery time series will affect the system performance and the recovery rate. The effect of the different recovery time series on the network reconfiguration and fault control has been analysed through the simulation of target network to determine the corresponding relationship between the residual power-supply capacity, the load recovery time series and the recovery rate, which can provide the basis of studying an optimal recovery strategy.

Benthic oxygen fluxes at the sediment-water interface (SWI) regulate the process and even direction of biochemical interfacial reactions; thus, they are crucial to the water quality. However, many medium- and large-sized reservoirs suffer from thermal stratification and human operations, lead to a significant impact on SWI oxygen exchanges. A 3-month-long noninvasive measurement of SWI oxygen fluxes was conducted in the Daheiting Reservoir using the eddy correlation method. Its result shows that reservoir stratification markedly affects the benthic boundary layer environment factors such as temperature, dissolved oxygen (DO) concentration, and hydrodynamics. In contrast, reservoir operations determine the benthic flow directions and its correlation to velocities in the mixed stage. A further discussion suggests that benthic temperatures mainly participate in the thermal structure rather than directly affecting the benthic fluxes. Conversely, it is DO concentrations coupled with hydrodynamics that control SWI oxygen fluxes. The flux is inhibited by DO shortage in anoxic conditions, but it is mainly controlled by hydrodynamics with redundant DO. Likewise, the hydrodynamics affects the fluxes by changing the diffusive boundary layer thickness, but this effect is also restrained by the DO field. These results indicate that a long-term and in-situ measurement of SWI oxygen fluxes in drinking reservoirs is of considerable significance to forecast water quality disasters, optimize operation plans, and ensure water security.