Search

The purpose of this study was to explore a new algorithm model capable of leverage deep learning to screen and diagnose specific types of left-to-right shunt congenital heart disease (CHD) in children.Using deep learning, screening models were constructed to identify 884 heart sound recordings from children with left-to-right shunt CHD. The most suitable model for each type was summarized and compared with expert auscultation. An exploratory analysis was conducted to assess whether there were correlations between heart sounds and left ventricular ejection fraction (LVEF), pulmonary artery pressure, and malformation size.The residual convolution recurrent neural network (RCRnet) classification model had higher accuracy than other models with respect to atrial septal defect (ASD), ventricular septum defect (VSD), patent ductus arteriosus (PDA) and combined CHD, and the best auscultation sites were determined to be the 4th, 5th, 2nd and 3rd auscultation areas, respectively. The diagnostic results of this model were better than those derived from expert auscultation, with sensitivity values of 0.932-1.000, specificity values of 0.944-0.997, precision values of 0.888-0.997 and accuracy values of 0.940-0.994. Absolute Pearson correlation coefficient values between heart sounds of the four types of CHD and LVEF, right ventricular systolic pressure (RVSP) and malformation size were all less than 0.3.The RCRnet model can preliminarily determine types of left-to-right shunt CHD and improve diagnostic efficiency, which may provide a new choice algorithmic CHD screening in children.

The magnitude of soil erosion and sediment load reduction efficiency of check dams under extreme rainstorms is a long-standing concern. The current paper aims to use check dams to deduce the amount of soil erosion under extreme rainstorms in a watershed and to identify the difference in sediment interception efficiency of different types of check dams. Based on the sediment deposition at 12 check dams with 100% sediment interception efficiency and sub-catchment clustering by taking 12 dam-controlled catchments as clustering criteria, the amount of soil erosion resulting from an extreme rainstorm event on July 26, 2017 (named “7·26” extreme rainstorm) was estimated in the Chabagou watershed in the hill and gully region of the Loess Plateau. The differences in the sediment interception efficiency among the check dams in the watershed were analyzed according to field observations at 17 check dams. The results show that the average erosion intensity under the “7–26” extreme rainstorm was approximately 2.03 × 104 t/km2, which was 5 times that in the second largest erosive rainfall in 2017 (4.15 × 103 t/km2) and 11–384 times that for storms in 2018 (0.53 × 102 t/km2 - 1.81 × 103 t/km2). Under the “7–26” extreme rainstorm, the amount of soil erosion in the Chabagou watershed above the Caoping hydrological station was 4.20 × 106 t. The sediment interception efficiency of the check dams with drainage canals (including the destroyed check dams) and with drainage culverts was 6.48 and 39.49%, respectively. The total actual sediment amount trapped by the check dams was 1.11 × 106 t, accounting for 26.36% of the total amount of soil erosion. In contrast, 3.09 × 106 t of sediment were input to the downstream channel, and the sediment deposition in the channel was 2.23 × 106 t, accounting for 53.15% of the total amount of soil erosion. The amount of sediment transport at the hydrological station was 8.60 × 105 t. The Sediment Delivery Ratio (SDR) under the “7·26” extreme rainstorm was 0.21. The results indicated that the amount of soil erosion was huge, and the sediment interception efficiency of the check dams was greatly reduced under extreme rainstorms. It is necessary to strengthen the management and construction technology standards of check dams to improve the sediment interception efficiency and flood safety in the watershed.

The Sichuan Basin (SCB) of China is known for excessive ozone (O

The complete, high-efficiency removal of cationic dyes in industrial wastewater before discharge becomes particularly urgent due to their biological toxicity. The membranes have emerged for removal of dyes benefiting from free separation, cheap component and easy operation, and thus aroused increasing research interest. Herein, the negatively charged hollow crosslinked aromatic polystyrene (PS) fiber (HPF-C) membrane has been successfully synthesized by a rapid room-temperature crosslinking of linear PS in HPF membrane, followed by deep sulfonation. The sulfonated HPF-C (HPF-C-S) membrane showed high experimental equilibrium adsorption capacity of 443.6 mg·g-1 for basic red 46 (BR46) with initial concentration of 50 mg·L-1. Its maximum adsorption capacity (346.0 mg·g-1) of methylene blue (MB) calculated by Langmuir model was about 5 times that of carboxylated cellulose fabrics (CCFs) membrane and higher than that of the most reported or commercially available nanofiber/nanoparticle adsorbents. Without external driven pressure, a flow rate of cationic dye solution through HPF-C-S membrane was up to 530 L·m-2·h-1 which was about 90 times that (6 L·m-2·h-1) of the CCFs membrane. The solution concentration through the HPF-C-S membrane always remained 0 mg L-1 (lower than the LODs of UV) before the permeation volume reached 4000 mL for 2 mg L-1 BR46 solution (In other words, 20 L of clean water could be obtained through per gram of membrane) and 1500 mL for 2 mg L-1 MB solution, respectively. The rejection ratio of 100% fully met the environmental criterion for wastewater disposal, indicating absolute superiority to the reported CCFs membrane that could not completely purify dyes. Moreover, the HPF-C-S membranes indicated excellent sustainability and stability. Besides, the kinetics, thermodynamics and mechanism behind these phenomena were studied.

Determining the soil quality of alluvial fans and its influencing factors is essential for understanding, utilizing, and protecting alluvial fans. In this study, a soil quality index (SQI) was constructed, and the soil of river terrace farmland was used as a control to evaluate the soil quality of alluvial fans in the Lhasa River Basin of the Qinghai-Tibet Plateau. Meanwhile, the influencing factors of soil quality of the alluvial fan were studied using correlation analysis. The results demonstrated that: 1) There is no significant difference in physicochemical indicators between the soil of the alluvial fan and river terrace farmland, namely the total nitrogen, total phosphorus, total potassium, available nitrogen, available phosphorus, available potassium, soil organic matter, pH, electrical conductivity, and soil erodibility; however, the coefficient of variation of each physicochemical indicator of the alluvial fan is greater than that of river terrace farmland. 2) The mean SQI value of alluvial fans and river terrace farmlands are 0.37 and 0.38, respectively. There is no significant difference between the values, demonstrating that the soil quality of alluvial fans is not lower than that of river terrace farmland. 3) The soil quality of alluvial fans has a highly significant positive correlation with vegetation coverage, land use, annual precipitation, altitude, and geomorphic divisions; a significant positive correlation with geomorphic location; and a highly significant negative correlation with annual temperature. Therefore, from the perspective of soil quality, the alluvial fan in the Lhasa River Basin can be used as a reserve arable land resource.

The catalytic amplification signal of polystyrene nanosphere (PN) is used to conveniently fabricate the resonance Rayleigh scattering (RRS)/surface-enhanced Raman scattering (SERS) dual-mode method to sensitively and selectively detect urea in food. PN has strong catalysis of the slow nanoreaction of citrate-Ag(I) to produce yellow silver nanoparticles (AgNP), which exhibit strong RRS effect and SERS effect with molecular probes. When aptamer (Apt) is present, the Apt is adsorbed on the PN surface, the catalysis is weakened, the AgNP is reduced, and the SERS/RRS signal is weakened. After adding urea to exhibit specific Aptamer reaction, the Apt is desorbed from the PN surface and the catalysis is restored. As urea increase, the desorbed PNs increase to produce more AgNPs indicator to increase SERS/RRS signal. The increase value △I of SERS/RRS is linearly to urea concentration. Therefore, a sensitive and selective SERS/RRS dual-mode method for urea is established based on aptamers-regulated the catalysis of PNs. This method is applied to the detection of urea in milk with satisfactory results. The relative standard deviation is 3.9–6.8% and the recovery rate is 94.5–102%.

We developed a Multinomial Nave Bayes Classifier to categorize the microblog posts into five types according to the text content of posts.Different types of information had significantly different propagation patterns in terms of scale and topological features.Social media users exhibited significantly different interaction patterns for different types of information at different stages. Social media has been playing an increasingly important role in information publishing and event monitoring in emergencies like natural disasters. The propagation of different types of information on social media is critical in understanding the reaction and mobility of social media users during natural disasters. In this research, we analyzed the dynamic social networks formed by the reposting (retweeting) behaviors in Weibo.com (the major microblog service in China) during Yiliang Earthquake. We developed a Multinomial Nave Bayes Classifier to categorize the microblog posts into five types based on the content, and then characterized the information propagation patterns of the five types of information at different stages after the earthquake occurred. We found that the type of information has significant influence on the propagation patterns in terms of scale and topological features. This research revealed the important role of information type in the publicity and propagation of disaster-related information, thus generated data-driven insights for timely and efficient emergency management using the publicly available social media data.

The physiological disorders in humans resulting from the excess dietary intake of manganese (Mn) via whole-grain food has attracted considerable attention. However, the speciation and bioavailability of Mn in wheat grains and their response to different phosphorus (P) fertilization rates are still unclear. In the current study, using a long-term field trial with P application rates of 0, 21.8, 43.6, 65.5 and 87.3 kg/ha, we examined changes in the concentration, distribution, and speciation of Mn of wheat grains using synchrotron-based X-ray fluorescence microscopy and X-ray absorption spectroscopy. The total Mn concentration in grains was found to be increased by phosphorus fertilization, especially in embryo in the form of Mn(II), but this phosphorus fertilization also decreased Mn concentrations in the nucellar projection. In this study, the speciation of Mn in different wheat grain tissues was examined, and results indicate that in calcareous soils, high rates of P fertilizers can increase Mn concentrations in wheat grain, including Mn which is likely to be of high bioavailability, and thus may increase the risk for human to expose to high Mn intake via whole-grain food.

Ozone (O3) is a typical photochemical product, generally with a maximum value in the late afternoon and a minimum value at night. This study aimed to investigate the variation characteristics of nocturnal O3 in a subtropical urban city (Shaoguan, Guangdong Province, China). The measurement campaigns were conducted from 23 July to July 28, 2020. O3 lidar, aerosol lidar, and wind profile lidar were utilised to detect the vertical distributions of the O3 concentrations, aerosol extinction coefficient, and wind velocity. The topographic features, pollutant data (PM10, PM2.5, O3, SO2, NO2, and CO), and meteorological parameters (temperature, humidity, wind speed, and wind direction) were also analysed. The results showed that the concentration of nocturnal O3 over Shaoguan peaked at midnight. The horizontal wind was dominated by southwest and south winds, and the vertical wind was dominated by downdrafts during the fixed-point observations in Shaoguan. Horizontal transport might have a high impact on the increase in the nocturnal O3 because of high pollutant emissions in upwind cities. This was further justified by the 24-h back trajectories of the air mass generated by the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model. Vertical transport of O3 in the lower or middle troposphere might be induced by the subtropical high and nocturnal mountain-valley breezes. Thus, the vertical mixing of O3 affects the O3 concentration at night.

The Sichuan Basin (SCB) located in southwestern China has long been considered the most polluted city cluster with exposure to unhealthy levels of ozone (O3) at times. However, the features of O3 regional transport and source contributions in SCB are poorly understood. In this study, ambient measurements, ERA5 reanalysis dataset, IASI O3 column, and the Weather Research and Forecasting-Community Multiscale Air Quality (WRF-CMAQ) modeling system coupled with the Integrated Source Apportionment Method (ISAM) module were used to investigate the formation mechanism and sources of a severe O3 episode in spring 2020 over the SCB. In the first stage of the O3 episode, a high-pressure system persisted over the western SCB and caused northeasterly wind fields, leading to enhanced regional transport from the northern boundary with the O3 contribution from the boundary exceeding 50% across the SCB. As the synoptic pattern evolved, southeasterly winds dominated the SCB and the stagnant zone over the Chengdu Plain confined O3 originating from the southern SCB and Chongqing city, leading to the accumulation of precursors and elevated O3 levels. During the O3 episode, transportation and industrial sources were major contributors to O3 formation especially for the Chengdu Plain and Chongqing city. In addition, the O3-rich air mass in the nocturnal residual layer that formed over Chongqing city was transported to the Chengdu Plain through southeastern corridor at 400-1600m above ground-level under the prevailing southeasterly winds. With sunrise and the development of the atmospheric boundary layer, the O3-rich air mass in the residual layer (RL) was entrained to the ground-level via vertical mixing, which further enhanced O3 pollution across the Chengdu Plain. Our results revealed the mechanism of regional transport via northeastern and southeastern corridors during an O3 episode and demonstrated the need for joint emission regulation across the SCB to mitigate O3 pollution.

A hematite/amorphous sulfur composite was prepared via simple heating hematite and α-sulfur in Teflon-lined autoclave at low temperature. The composite was characterized by X-ray diffraction (XRD), Raman spectrum, Thermal Gravity Analysis (TGA), Transmission Electron Microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The results revealed that an allotrope sulfur at 5–37% weight percent was found in the composite. After sulfuration, Sn2- or S22- was doped in the lattice of hematite, large amounts of OH and SO4 were adsorbed on the surface of hematite. Hematite/amorphous sulfur composite had superior photo-Fenton activities than pure hematite. This work also demonstrated that amorphous sulfur also had the activity of photo-Fenton catalysis. OH- and SO4 radicals facilitated dye adsorption and acted as a bridge to link H2O2. Moreover, SO4 radicals on hematite served as electron trapping center that can receive photo-induced electron from conduction band of hematite and transfer it to the adsorbed H2O2, increasing the rate of photo-Fenton reaction eventually.

This study presents the use of Cinnamic Hydroxamic Acid (CHA) as a novel collector of malachite. The flotation performance was evaluated by microflotation experiments. The mechanism of CHA adsorption at malachite surfaces was studied by contact angle measurements, zeta potential measurements, infrared spectroscopy (FTIR), and X-ray Photoelectron Spectroscopy (XPS). The microflotation experiments demonstrated that the CHA improved selectivity in comparison to benzohydroxamic acid (BA) during malachite flotation. Artificial mixed mineral flotation experiments verified that malachite could be separated from calcite effectively with the CHA collector. The results from contact angle measurements indicated that the hydrophobicity of the malachite surface was increased after CHA treatment. Zeta potential and infrared spectroscopy measurements implied that the adsorption of CHA at malachite. XPS analysis demonstrated that the C and N concentration on the malachite surface increased, with a concomitant decrease in Cu concentration.

A method used to create products by forming an extruded shape or forcing material through a die or orifice that uses an extruder to produce a semi-finished or finished product. The Spiral 3D model of screw extruder causes unstable production in cable insulation. This productivity instability is caused by the pulsating pressure gradient of the molten polymer in the melding tool at the extruder. The frequency of the pressure pulsation of the molten polymer in the dosing zone is based on the boundaries of statistical processing and the screw speed. This system provides instant production stability between insulation applications, increases the regularity of insulation core diameter, and ensures the performance of the final manufactured cable's predefined service quality parameters.

Due to the non-degradability of lead, it in food poses a huge threat to human health. Therefore, it is very important to establish a sensitive and rapid detection method for Pb2+ in food. In this paper, a new palladium-doped covalent organic framework (COFPd, TpPaPd) was prepared using CO as the reducing agent, and it was characterized in details. Experiments show that TpPaPd strongly catalyze the reduction of Ni(II) by sodium hypophosphite to form Ni-P alloys, and the system has a surface plasmon resonance (SPR) absorption peak at 395 nm. Combing the nanocatalytic reaction with the DNAzyme reaction of the aptamer (Apt)-Pb2+-hemin (HM), a new SPR spectrophotometric method was established to detect 0.001−0.1 nmol/L Pb2+ in food sample, with a detection limit of 0.0004 nmol/L.

Under microwave conditions, Au-doped carbon dots (CDAu) were prepared using fullerene as a precursor, and characterized in details. It is found that CDAu can strongly catalyze the reaction of HAuCl4-fructose to generate gold nanoparticles (AuNPs). The new nanocatalytic reaction was studied by surface-enhanced Raman scattering (SERS), resonance Rayleigh scattering (RRS) and absorption (Abs) spectrometry. Based on the specific aptamer (AptAs)-As+3 reaction mediated the CDAu-HAuCl4-fructose nanoreaction, and the products of AuNPs as SERS/RRS/Abs trifunctional indicator nanoprobes, a new trimode Apt assay strategy was developed for detection of ultratrace As+3. A 0.07–0.70, 0.10–0.60 and 0.20–0.70 μg L−1 were determined by SERS, RRS and Abs, with detection limits (DL) of 0.04, 0.06, 0.10 μg L−1 respectively. The aptamer-regulation CDAu catalytic amplification platform can be also used to assay 1.7–13.3 nmol L−1 Pb2+ and 2.0–12 μmol L−1 Hg2+, with DL of 0.80 nmol L−1 and 0.90 μmol L−1 respectively.

With the rapid popularization of China’s agricultural mechanization, energy consumption in China’s agricultural activities has been increasing significantly. Based on the agricultural sample data from 2000 to 2017, this study explores the substitution effect and rebound effect of China’s energy consumption in agricultural sector. In order to characterize the asymmetric response, this paper applies asymmetric price decomposition method and seemingly unrelated regression model to conduct the research. Some important results are found as follows. First, own-price elasticity of energy, labor and capital in China’s agricultural sector are −0.25, −0.23, and −0.33 during the study period, showing all the inputs are lacking of price elasticity of demand. Second, the substitution rate of capital for energy is 0.21 while the substitution rate of energy for capital is 0.17, which indicates that reducing capital cost is a more effective way than raising energy price for agricultural energy-saving goal. Second, the rebound rate of energy consumption is 74.78%, meaning that the improvement of energy efficiency relying on technological progress can only achieve 25.22% of energy saving effect. Fourth, the energy rebound rate of China’s agricultural sector is much higher than those of other sectors and presents certain regional characteristics over the study period. Based on these research results, measures such as accelerating market-oriented reform of input factors, increasing agricultural subsidies, optimizing agircultrual energy structure, and weeding out backward agricultural machineries are put forward for the development of China’ agricultural sector.

Characteristics of soil erosion under extreme rainfall conditions are indicators of the ecological restoration measures as well as the rationality of land use patterns in the region. To this end, 12 dam-controlled catchments were selected for investigation after an extreme rainstorm event in the northern Shaanxi Province on 25–26 July 2017 (known as the “7.26” rainstorm). Soil erosion intensities in the 12 catchments were obtained by excavations of sedimentation profiles and sedimentation area measurements. Digital orthophoto maps and digital terrain models by unmanned aerial vehicle were generated to characterise land use types and areas, slope gradients, and the distance from the land to the boundary of dam-land along the flow accumulation path. Stepwise regression analysis was used to determine the main factors affecting catchment erosion intensity. Results showed that the average sedimentation thickness and overall soil erosion intensity across the 12 catchments ranged from 0.16 to 1.67 m and 10295–49227 t km−2, respectively. Soil erosion caused by the extreme rainstorm was 10–50 times of the soil loss tolerance on the Loess Plateau (1000 t km−2 year−1). Stepwise regression analysis revealed that the more similar the shape of a catchment to a circle, the closer the distance between the slope-cropland and dam-land, the larger the erosion modulus within the catchment. Furthermore, the presence of a cement road along the valley shoulder greatly reduced the modulus of soil erosion. These findings indicate that the existing ecological conditions in the dam-controlled catchments were not able to effectively resist erosion under the extreme rainfall conditions of this event. Thus, optimising the distribution of land use types within catchments should be a focus for soil erosion control.

Graphene-on-silicon (Gr/Si) Schottky junction solar cells have recently attracted considerable interest as promising candidates for low-cost photovoltaic applications. However, the efficiency of Gr/Si cells is still much lower than that of crystalline Si solar cells, which is mainly attributed to the interface recombination of carriers due to the low Gr/Si Schottky barrier. Herein, a few-layer hexagonal boron nitride (h-BN) is introduced to engineer the Gr/Si interface for improving device performance. The h-BN can act as an effective electron-blocking/hole-transporting layer due to its unique properties and appropriate band alignment with Si, and thus the interface recombination was suppressed and the open circuit voltage was remarkably increased. On the other hand, the series resistance of solar cells decreases due to an improving conductivity of graphene on h-BN, leading to an increased short circuit current density. Furthermore, the interface defects and contamination arising from the layer-by-layer transfer process can be eliminated by using a directly grown Gr/h-BN heterostructure. As a result, a maximum efficiency of 10.93% was achieved by combining h-BN interlayer and co-doping of graphene with Au nanoparticles and HNO 3 , which shows the great potential of the novel Gr/h-BN/Si solar cells.

LaCuOS nanopowder was synthesized by a novel precipitation/reduction route using commercially available La(NO 3 ) 3 ·6H 2 O, CuSO 4 ·5H 2 O and NH 3 ·H 2 O as the starting materials. Detailed characterizations of the synthesized products were obtained by differential thermal analysis and thermogravimetry (DTA–TG), fourier transform infrared spectroscopy (FT-IR), X-ray diffractometry (XRD), transmission electron microscopy (TEM), and UV–vis absorption spectroscopy. The results revealed that the precursor, composed of amorphous lanthanum and copper hydroxide sulfate, could be converted into pure LaCuOS nanopowder by calcination at 800 °C for 5 h in flowing argon and hydrogen atmosphere (90%Ar+10%H 2 ) resulting in quasi-spherical and agglomerated morphology with ~50 nm in size. LaCuOS has been characterized to be a semiconductor with an optical band gap of 3.1 eV by UV–vis absorption spectroscopy.

A new Au nanocluster-doped covalent organic framework (AuCOF) was prepared and characterized by electron microscopy and molecular spectroscopy. Based on aptamer-mediated COF nanocatalytic amplification signal strategy, a dual-mode analytical platform of surface-enhanced Raman scattering/resonance Rayleigh scattering (SERS/RRS) was established to detect ultatrace small molecules. The catalysis of AuCOFs on AgNO3-citrate nanoreaction was investigated. The formed yellow silver nanoparticles (AgNPs) exhibit strong RRS and SERS effect. The aptamer (Apt) suppressed the catalysis of AuCOFs to cause the RRS and SERS signals decreasing. Upon addition of target organic molecule such as adenosine triphosphate (ATP), the specific aptamer reaction occurred to restore the catalysis of AuCOFs, which will generate more AgNPs, and resulting in a linear increase in the signals of RRS and SERS. On this basis, inelastic scattering SERS, elastic scattering RRS and SERS/RRS dual-mode biosensors were established for small organic molecules such as ATP, urea, and estradiol, which is of high sensitivity and good accuracy compared to the single mode scattering method.

Neurotoxicant exposure by the over intake of manganese (Mn) and crop Mn accumulation related with fertilization and other agronomical measures had attracted wide attentions, while information is limited about variations in grain Mn with geographical changes in both soil and precipitation. A total of 438 wheat-grain site samples were therefore collected from two regions that were categorized by soil pH (non-acidic, pH > 7 and acidic, pH

In this work, decanedioic hydroxamic acid (DDHA) was introduced as a novel collector for the flotation separation of bastnӓsite and calcite, and the results were compared with those obtained for the conventional hydroxamic acid collectors benzohydroxamic acid (BHA) and octyl hydroxamic acid (OHA). The microflotation results showed that DDHA had better selectivity than BHA and OHA for the flotation of bastnӓsite from calcite. The flotation of artificially mixed minerals confirmed that the effective separation of bastnӓsite from calcite could be realized in the presence of DDHA. The zeta potentials of mineral surfaces with or without these collectors were measured, and the results indicated that DDHA strongly interacted with the bastnӓsite surface but was not adsorbed on the calcite surface.

Kawasaki disease (KD) is the leading cause of acquired heart disease in children. Its prompt treatment can effectively lower the risk of severe complications, such as coronary aneurysms. However, accurately diagnosing KD at its early stage is impracticable given its unknown pathogenesis and lack of pathognomonic features. In this study, we investigated data-driven approaches by using a cohort of 10,367 patients extracted from electronic health records for early KD assessment. The incompleteness of clinical data presents group-based missing patterns associated with different clinical assessment measures. To address this problem, we developed a method integrating feature clustering to enable matrix-based representation and convolutional neural networks (CNN) for feature extraction and fusion to explicitly exploit the multi-source data structure. Integrating missing data imputation methods with the proposed method demonstrated superior accuracy (an AUC of 0.97) compared with a number of benchmark methods. The present method shows potential to improve clinical data mining. Our study highlighted the feasible utilization of matrix-based feature representation and CNN-based feature extraction for incomplete clinical data mining to support medical decision-making.

The Sichuan Basin (SCB) has suffered from serious ozone (O3) pollution in recent years, especially in summer. However, the formation and evolution mechanisms of O3 pollution in the SCB remain poorly understood. In this paper, we comprehensively investigated the causes of elevated ozone concentrations in Chengdu in July 2017 with a combination of field measurements and the WRF (Weather Research and Forecasting)-CMAQ (Community Multi-scale Air Quality) model simulations. The ozone formation characteristics of continuous O3 episodes and non-O3 episodes were compared. Higher temperature (T), stronger solar radiation (SR), lower relative humidity (RH) and weaker winds were conducive to O3 formation during ozone episodes. The O3 concentration during O3 episodes (202.6 μg m−3) was significantly higher than that during non-O3 episodes (122.7 μg m−3), attributable to the higher volatile organic compounds (VOCs) concentration (34.0 ppbv compared with 27.5 ppbv) despite comparable NOx concentrations during O3 episodes. The results of positive matrix factorization (PMF) for ambient VOCs showed that gasoline vehicle exhaust and solvent usage were the dominant sources during the month. However, the increasing source attributions from the petrochemical industry and biogenic emissions were responsible for the elevated VOCs concentrations during O3 episodes. The relative contributions of local emission and regional transport to ozone were quantified during two O3 episodes by conducting numerical sensitivity experiments. In the first episode, namely, the “O3-regionally transported” pattern, high ozone concentration in Chengdu was primarily due to the regional transport of ozone and ozone precursors through vertical mixing and horizontal advection from upwind areas (central and eastern SCB) when easterly or southeasterly winds prevailed over the SCB. In contrast, in the second episode, namely, the “O3-locally dominated” pattern, high local emissions under favorable meteorological conditions are the major reason for elevated ozone concentration. The process analysis results from the CMAQ model suggested that the vertical transport of O3 that formed at the upper levels from intense gas-phase chemistry reactions was a dominant contributor to diurnal O3 enhancement in O3 episodes by 45 μg m−3, while horizontal transport contributed more than 80% of the nocturnal O3 concentration. This study provides a better understanding of ozone photochemical formation and regional transport mechanisms in the SCB under complex terrain conditions, and contributes to ozone pollution prevention in other basins around the world.

Well-defined hierarchical hemoglobin-like LiMnPO 4 microspheres were successfully synthesized by a simple hydrothermal method. The hemoglobin-like LiMnPO 4 microstructures are composed of numerous nanorods with the diameter of about 100 nm. Citric acid was chosen as chelating reagent and it was found that its addition played an important role in controlling the hemoglobin-like morphology of the products. The morphological evolution of the products has been studied and a possible formation mechanism of the hemoglobin-like structure was proposed according to the time dependent experimental results and analysis. After carbon coating, the as-prepared LiMnPO 4 cathode demonstrated a flat potential at 4.1 V versus Li/Li + with a specific capacity close to 110 mA h g − 1 at 0.1 C, along with good cycling stability.