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The performance and operation stability of proton exchange membrane fuel cells (PEMFCs) are closely related to the transportation of reactants and water management in the membrane electrode assembly (MEA) and flow field. In this paper, a new three-dimensional wave parallel flow field (WPFF) in cathode was designed and analyzed throughout simulation studies and an experimental method. The experimental results show that the performance of PEMFC with WPFF outperforms that of PEMFC with straight parallel flow field (SPFF). Specifically, the peak power density increased by 13.45% for the PEMFC with WPFF as opposed to PEMFC with SPFF. In addition, the flow field with area of 11.56 cm2 was formed by the assembly of transparent end plate used for cathode and the traditional graphite plate used for anode. To understand the mechanism of the novel flow field improving the performance of PEMFC, a model of PEMFC was proposed based on the geometry, operating conditions and MEA parameters. The thickness of gas diffusion layers (GDL), catalytic layers (CL) and proton exchange membrane were measured by scanning electron microscope. The simulation result shows that compared with SPFF, the WPFF based PEMFC promote the oxygen transfer from flow channel to the surface of CL through GDL, and it was beneficial to remove the liquid water in the flow channel and the MEA.

Coal-to-methanol enterprises in China face many risk factors that pose a serious threat to the safety of the company's production. Therefore, it is imperative to conduct risk assessments of coal-to-methanol plants. A failure mode and effects analysis (FMEA) is a significant analysis method in risk evaluation. However, due to the uncertainty in the risk analysis process, the assessment results may not be sufficiently accurate. To reduce the uncertainty, especially randomness and fuzziness in the evaluation process, a cloud model (CM) is utilized to improve the FMEA, and the FMEA-CM approach is proposed. First, the qualitative language terms are converted into the quantitative numerical characteristics of the cloud model, enabling the fuzziness and randomness in the evaluation process to be comprehensively considered. Second, the cloud weights of S, O and D are calculated by using the interval analytic hierarchy process (IAHP) and the CM. Moreover, the cloud risk priority number (CRPN) is put forward to improve the accuracy of the traditional RPN, and the CRPN algorithm is given. Finally, to rank risk events, the technique for order preference by similarity to an ideal solution (TOPSIS) method, improved by cloud distance based on Hamming distance, is put forward. A coal-to-methanol plant in Yinchuan, China, is introduced to demonstrate the applicability of the proposed FMEA-CM approach. Compared with the results obtained from the traditional FMEA and fuzzy TOPSIS method, the results obtained from the adoption of the FMEA-CM approach show that the FMEA-CM is a more accurate and effective method for the risk assessment of a coal-to-methanol plant.

Water management is crucial to achieve both high-performance and durability of proton exchange membrane fuel cell (PEMFC). Therefore, it is necessary to investigate the dynamic behavior of droplets in PEMFC channel for water management. In this paper, we explore the kinetics of droplets in a 3D flow field by experimental and theoretical analysis. More specifically, we examine the following four perspectives: 1) the movement and falling of droplets, and their force and deformation, 2) the superiority of 3D flow field drainage, 3) the pressure and viscous force under different scenarios including varying droplet sizes and velocities, and 4) the expression describing the shape change of droplets. The results show that the 3D flow field has a greater driving force on droplets and that their deformation affects the discharge of liquid water. Throughout the study, we provide better understanding of droplet dynamic in PEMFC gas channels. It enables to optimize the design and working conditions of these channels.

Groundwater is a very important natural resource for humanity, however, the degradation of groundwater quality caused by anthropogenic activities may pose a serious hazard to human health and ecosystem. In this study, 143 groundwater samples were analyzed to investigate the spatiotemporal variations of hydrochemistry, groundwater quality and potential human health risk of groundwater in Jinghe River Basin, Chinese Loess Plateau. Based on the mean concentrations value (MCV) and over-standard rate (OSR), the groundwater in Jinghe River Basin were divided into three groups: Group Ⅰ (high MCV: greater than standard values and high OSR: ≥ 10 %) contains TDS (total dissolved solids), TH (total harness), SO

Groundwater resources are increasingly exploited for industrial and agricultural purposes in many arid/semi-arid regions globally. In order to gain a harmonious development among groundwater resources and economic benefits, urgent investigation of the impacts of anthropogenic activities on the groundwater chemistry is required. Understanding hydrochemical mechanism of groundwater in Yinchuan Plain, arid and semi-arid area in Northwestern China, plays a significant role in water resources planning in this ecologically sensitive area. In this paper, a total of 460 phreatic water samples were collected, including 58 water samples containing isotopic data (D and 2 H). Results demonstrate that water chemistry type and isotopic data of phreatic water presents a zonation characteristic from west to east and from south to north. In the eastern part of the Helan Mountain (A 1 zone), the type of hydrochemistry is mainly HCO 3 ·SO 4 -Ca·Mg, SO 4 ·HCO 3 -Ca·Mg, which is mainly recharged by the bedrock fissure water of Helan Mountain. However, in the southern Qingtongxia (A 2 zone) are HCO 3 -Na HCO 3 -Ca·Mg, which receives irrigation and spring water recharge. Phreatic aquifer in Multi-layered structure zone (A 3 zone) reflect multiple recharge sources to the aquifer, the water chemistry demonstrates diverse variations. The anion was dominated by the HCO 3 , while the cation is dominated by sodium. The predominant controlling factors of phreatic water hydrochemistry are divided into anthropogenic activities and natural conditions. Natural conditions mainly include the existence form and lithology of the aquifer, sources of groundwater recharge, soil salinity, and evaporation, mineral dissolution, ion exchange and adsorption and mixing effect. Meanwhile, among natural factors, minerals dissolution in groundwater is the main process dominating the hydrochemical evolution of the groundwater. The other is anthropogenic activities which can be classified as groundwater pollution, excessive exploitation or excretion of groundwater, and excessive groundwater recharge.

Anammox is a distinctive bacterium that is extremely sensitive to and inhibited by organic matter. This weakness becomes a limiting factor for the application of anammox to treat wastewater especially that the underlying mechanisms in the inhibition of phenol remain unclear. In this study, phenol was chosen to determine the possible factors leading to the inhibition of anammox through community variation and molecular simulations. Results of the short-time batch experiment showed that 400 mg L−1 or 1000 mg L−1 of phenol immediately inhibited the anammox activity. Profiles from 16S rRNA sequences showed that the community structures remained unchanged during the first four hours. Molecular simulation between phenol and the key enzyme hydrazine synthase (HZS) showed that phenol combined with HZS and even had the ability to competitively bind with HZSα-haem αI and HZSγ-haem γI sites.

Datong basin is one of the most important agriculture zone of Shanxi Province, China, where intensive fertilizer and pesticide applications cause the groundwater contamination. Hence, it is necessary to carry out groundwater specific vulnerability assessment of nitrate. The prediction accuracy of conventional DRASTIC model for groundwater vulnerability assessment is severely limited by the inherent subjectivity in determining main parameters, rating scales and weighting coefficients. This paper attempts to overcome these problems by changing the evaluation parameters, parameters rating and weight calculation method. Based on the hydrogeological conditions and nitrate pollution characteristics of Datong Basin, the traditional groundwater vulnerability model DRASTIC was improved, called DRSTIC-LE model to assess the specific vulnerability of nitrate, which involves Depth of water table (D), Net recharge (R), Soil media (S), Topography (T), Impact of the vadose zone (I), hydraulic Conductivity (C), land use type (L), and groundwater exploitation (E) as evaluation parameters. And the theoretical weight of each parameter were determined with the aid of the improved weights determination method by the effective combination of the entropy weight method and analytic hierarchy process. Moreover, single-parameter sensitivity analysis was performed to evaluate the effect of each parameter on the groundwater specific vulnerability. According to the results of groundwater specific vulnerability map, very high and high vulnerability mainly situated in central, northern and northeastern portion of study area, with 6.25%, 17.93% of total area, respectively. Also, single-parameter sensitivity analysis represented that I and D are the main parameter which impacts groundwater to pollution while C contributes least to pollution in the Datong basin. The model is validated with the measured nitrate concentration and results have shown better correlation between SVI and nitrate concentration. Additionally, by comparing the correlation between the effective weights and the theoretical weights calculated by the three methods (EW, AHP and EW-AHP method), we can see that prediction accuracy of the EW-AHP method is higher than other methods. The research established the efficacy of EW-AHP method as a method of determining weights and provided a basis for regional control of groundwater nitrate pollution.

Pollution of potentially toxic metals (PTMs) in road dust (RD) is becoming an important threat to the urban environmental quality and human health. The chemical speciation of PTMs is an important index charactering the risks, which may also closely relate to the pollution level and source but it was poorly understood. In this study, the chemical speciation of Cd, Cr, Cu, Ni, Pb and Zn in the RD of a megacity (Nanjing), China was determined following an optimized BCR (proposed by the European Community Bureau of Reference) sequential extraction procedure to assess their pollution and potential eco-risk and to explore the variations of metal chemical speciation with the pollution levels and sources. Total concentrations of the PTMs in the RD were enriched 1.4- to 123-fold relative to the subsoil with median contamination factors (CF) of 6.7 (Pb), 6.0 (Cu), 5.5 (Cd), 4.0 (Zn), 2.0 (Cr) and 1.9 (Ni). Pollution of the PTMs should be mainly from industrial and traffic emissions and showed high CF values in the northern industrial zone. Whereas, the chemical percentages of each metal showed relatively narrow spatial variations and were not statistically correlated with the pollution levels (p = 0.05). Comparing of similar studies indicates that no regular patterns existed in chemical percentages for each metal in RD polluted by the traffic and/or both the industrial and traffic sources. In the RD of Nanjing, Pb was mostly associated with reducible phase, Cd and Zn were mainly present in acid-soluble phase, Cu was mostly concentrated in oxidizable phase, while Cr and Ni were predominantly present in residual phase. As the typical pollutants, anthropogenic Cd, Cu, Pb and Zn were mostly associated with the potential mobile phases but also with the residual phase in the RD of Nanjing, causing 1.4- to 3.0-fold increase in the mobility. Combining the assessments from eco-risk index, risk assessment code and sediment quality guidelines with the pollution levels and chemical speciation, we deduced that Cd, Cu, Pb and Zn may pose certain eco-risk upon transport into the aquatic system and soil, and Cd should be primarily concerned.

The properties of flour from polished rice that had been subjected to various milling conditions were investigated. Waxy, low- and high-amylose rice were milled at different speeds (1050, 950, and 750 r/min) for different durations (20, 40 and 60 s). The swelling power was increased with milling duration and speed compared to brown rice flour. The solubility of milled waxy rice flour was substantially lower than for brown rice flour, but for milled low- and high-amylose rice flour, it was unchanged or slightly reduced. The peak viscosity of low- and high-amylose rice flour was more affected by milling duration, whereas the final viscosity was more affected by milling speed. Total milling revolutions led to greater effect on pasting properties of WRF than LARF and HARF. Milling duration was a greater determinant of thermal properties than was milling speed. Milling conditions had different effects on the digestibility of different rice flours. Milling speed had less effect on digestibility than did milling duration for waxy rice flour, but speed had a greater effect on the digestibility of low- and high-amylose rice flour. This study showed that both milling duration and speed impacted the physicochemical and digestibility properties of different rice flours, but to different extents.

Recently, an increasing number of tunnels were constructed in high-geotemperature regions and threatened with heat hazards, leading to an urgent required to analyze heat exchange characteristics and manage underground environment in these tunnels. To obtain the actual airflow and temperature field of high-temperature tunnel, a full coupled three-dimensional model incorporated with buoyancy flow was established describing the dynamic heat transfer process. The influence of buoyancy flow on temperature field in the radial and longitudinal direction of tunnel has been investigated respectively. Accounting for the buoyant effect is crucial to heat conduction and convection within tunnel, and it cannot be ignored in predicting air temperature with a large temperature difference tunnel. Additionally, this study highlights the significant effect of the presence and magnitude of groundwater flow on temperature variations and heat transfer of tunnel. When the magnitude of groundwater flow is larger than 0.01 m/d, the groundwater condition will significantly influence the temperature distribution of surrounding rock and airflow. The groundwater flow increases the temperature difference of tunnel and induces a clearer buoyancy effect inside the tunnel. As the groundwater flow direction angle increases from 0° to 90°, the influence of groundwater on heat transfer of tunnel increases first and then stabilizes. The longer the length of the seepage region is, the larger the average temperature at tunnel exit is, and the slower the temperature decreases with time. Furthermore, an orthogonal test was performed to investigate the influence degree of major factors on heat exchange of tunnel through range analysis. This study supplements the existing numerical model and research, making it more accurate to predict the thermal environment of tunnel, and guides optimization of tunnel design.

Meta-learning aims to train a classifier on collections of tasks, such that it can recognize new classes given few samples from each. However, current approaches encounter overfitting and poor generalization since the internal representation learning is obstructed by backgrounds and noises in limited samples. To alleviate those issues, we propose the Unsupervised Descriptor Selection (UDS) to tackle few-shot learning tasks. Specifically, a descriptor selection module is proposed to localize and select semantic meaningful regions in feature maps without supervision. The selected features are then mapped into novel vectors by a task-related aggregation module to enhance internal representations. With a simple network structure, UDS makes adaptation between tasks more efficient, and improves the performance in few-shot learning. Extensive experiments with various backbones are conducted on Caltech-UCSD Bird and miniImageNet, indicate that UDS achieves the comparable performance to state-of-the-art methods, and improves the performance of prior meta-learning methods.

Removal of excessive nutrients (N and P) is one of the most concerned issues for wastewater treatment. This study presents a paired electrolytic system consisting of Al cathode and RuO2/Ti anode for the simultaneous removal of phosphate and ammonia in wastewaters. The comparative study on the dissolving behaviors of Al cathode and Al anode showed that Al cathode could achieve a continuous and stable dissolution of aluminum, thereby forming flocs and small amounts of water soluble aluminum species for decontamination. The electrogenerated OH– in the vicinity of cathode raised the local alkalinity and caused the chemical dissolution of aluminum. According to the experiment of non-electrolytic dissolution of aluminum in alkaline solution, the local pH resulting in the cathodic dissolution of Al was estimated. The paired electrolytic system showed the capability to simultaneously remove ammonia and phosphate in simulated wastewater, and the pH neutralizing effect in association with the formation of Al species could promote the electrochemical oxidation of ammonia. When the paired electrolytic system was applied to the treatment of landfill leachate, 96.9% of ammonia nitrogen, 87.4% of total phosphorous and 89.9% of COD could be eliminated after three hours of electrolysis at 80 mA/cm2. The results shown in study reveal that the dissolution process of Al cathode enables a convenient control on the dissolving-out amounts of aluminum via regulating the applied current density, and the paired electrolytic system can be developed as an energy-efficient electrochemical wastewater treating method.

The use of cooling garments is emerging as an effective, convenient, and energy-efficient way to maintain thermal comfort, which is crucial for conserving physical and psychological health and for avoiding potentially life-threatening situations. Current cooling garments are generally bulky and have short operating periods, uncontrollable cooling capacity, and low effectiveness. Here, a novel man-portable cooling garment based on thermoelectric refrigeration was designed, and the heat generated by body is absorbed by capillary tube and dissipated in semiconductor refrigeration system. The coolant is circulated in the pipeline to recover residual cold energy and improve the thermal stability of the system. Several performance tests were conducted in a simulated hot environment to evaluate and to optimize refrigeration efficiency and cooling effectiveness. The results indicated that the system was capable of providing a water temperature of 15.7 °C and cooling power of 340.4 W, with a coefficient of performance of 3.40 at 100 W of electrical power and a climatic chamber at 30 °C. Additionally, the operating environment of the system significantly influenced the cooling capacity of the garment; and the cooling power of the system was significantly improved by increasing the heat dissipation capacity. The increase in electrical power was limited by constant heat dissipation capacity restrictions. The wearing trial confirmed the effectiveness of the thermoelectric cooling garment. Furthermore, our study improved the understanding of performance characteristics for the thermoelectric cooling garment, and a road map for the further development of thermoelectric cooling garments was suggested.

Heat hazard is major challenge for the safe and efficient exploitation of deep resources. Understanding the heat transfer behaviors in roadway is the premise of temperature prediction and ventilation design. A fully coupled model incorporated with a moving mesh method was developed, which considers the convective heat transfer between surrounding rock and airflow, unsteady-state heat transfer in rock, and non-isothermal flow in roadway. The characteristics of thermal performance and its evolution law in an excavating roadway were obtained. The numerical model was validated against previous experimental data with a deviation of less than 3%. Analysis of the airflow and temperature field revealed the characteristic of convection heat transfer in the wall and local heat accumulation in roadway. The air temperature in roadway is associated with the airflow characteristics, and a local high temperature zone is presented in the vortex zone. By comparing the heat flux of the surrounding rock and excavation condition, it is found that the heat released from the working face poses a crucial effect on the airflow temperature in roadway. The present study provided a robust theoretical basis for improving cooling efficiency and thermal comfort in roadway construction.

Objective: To investigate the relationship between Dental Porphyromonas Concentration and Esophageal Cancer in Guangdong, China. Methods: Research objects divided into two groups: disease group and health control group. There were 43 cases in the disease group and 43 cases in the control group, on a 1 to 1 ration matching. Two groups of individuals were retrieved from the Guangdong Provincial Hospital database between year 2016 June to 2018 June. Age, gender, race and region are strictly matched. Both of the Cases and the Controls are processing through: a. Specimen collection, b. DNA extraction, c. High-throughput sequencing (screening stage), d. Quantitative determination of target bacteria in the samples of the experimental group by Q-PCR, e. Statistical analysis of experimental data. Two sample t-test are using to detect whether have difference on concentration of Dental Porphyromonas between cases and control group. SAS 15 windows version is used as analytic tools. Results: We found the mean of concentration on Dental Porphyromonas in Esophageal Cancer Group (Cases) are statistically higher than Healthy Group (Controls), with a mean of 0.0157 in cases versus 0.0025 in controls, which is 6.54 times higher in Esophageal Group, compare with control group, with P

The Construction of mega-dams has attracted worldwide attention due to their impacts on channel scouring from downstream regions to estuaries. However, the impacts of dams and near-end engineering on the evolution of large alluvial estuarine channels are unknown. In this study, the morphological evolutionary process and response regime of the North Channel (NC) in the Yangtze estuary was examined between 1986 and 2016 by using hydrology, multibeam echo sounding and historical bathymetry datasets. The results showed that the NC exhibited overall erosion with a total volume of 9.09 × 108 m3 over the past 30 years. We concluded that sediment load reduction in the river basin was the main reason for channel scouring. However, the short-term influence of near-end engineering on the local channel evolution process could not be ignored. For example, the construction of the north-south channel bifurcation project resulted in slight siltation of the NC with a total volume of 0.12 × 108 m3 from 2002 to 2007 despite the sediment load decreasing from 3.4 × 108 t to 1.8 × 108 t since the closure of the Three Gorges Dam (TGD). Furthermore, after construction (2007–2016) of the Qingcaosha Reservoir, the largest reservoir in the Yangtze estuary, the NC experienced extensive scouring near the reservoir and limited morphologic changes to the margin channel far from the reservoir. The maximum scouring depth near the reservoir reached ~13.5 m. In terms of the scour rate, the value of the average annual scour depth was 23–24 times the riverbed erosion rate caused by sediment load reduction. Therefore, a re-evaluation of the unexpected impacts of near-end engineering on the local Yangtze estuarine channels is urgently needed.

Accurately evaluating soil water-erosion dynamics and drivers is crucial for mitigating soil and water loss. To simulate the potential or net soil erosion process in China’s Hexi region (a 2.3 × 105 km2 area including three river basins), this study attempted to integrate the transport limited sediment delivery (TLSD) function within the revised universal soil loss equation (RUSLE) model (the spatial resolution of the maps was 90 × 90 m). A geographically weighted regression model was used to evaluate the contribution of influencing factors to the net water-erosion rate and the soil and water conservation benefits of the “Grain to Green Program” (GTGP) (The area proportion of land types in 2015: 6.84% (cultivated land), 3.48% (forest land), 21.68% (grassland), 66.69% (unused land), 0.75% (water), and 0.56% (construction land). The results revealed that the RUSLE-TLSD model could reliably simulate the soil erosion process in Hexi (the Nash-Sutcliffe model efficiency coefficient exceeded 0.602). The potential water erosion rate was between 6.24 and 31.01 t/ha/a from 1982 to 2015, and the net water erosion rate declined slightly, with a slope of −0.0029. Water erosion was severe in high-altitude areas (altitude > 3306 m) with slopes of more than 21° and annual precipitation above 235 mm and weak in low-altitude areas (altitude

Insufficient understanding of the hydrogeochemistry of aquifers makes it necessary to conduct a preliminary water quality assessment in the southern region of Ordos Basin, an arid area in the world. In this paper, the major ions of groundwater have been studied aiming at evaluating the hydrogeochemical processes that probably affect the groundwater quality using 150 samples collected in 2015. The two prevalent hydrochemical facies, HCO3Mg·Na·Ca and HCO3Mg·Ca·Na type water, have been identified based on the hydrochemical analysis from Piper trilinear diagram. Compositional relations have been used to assess the origin of solutes and confirm the predominant hydrogeochemical processes responsible for the various ions in the groundwater. The results show that the ions are derived from leaching effect, evaporation and condensation, cation exchange, mixing effect and human activities. Finally groundwater quality was assessed with single factor and set pair methods, the results indicate that groundwater quality in the study region is generally poor in terms of standard of national groundwater quality. The results obtained in this study will be useful to understand the groundwater quality status for effective management and utilization of the groundwater resource.

In recent years, the spontaneous combustion of coal has led to numerous gas explosions in mines that have resulted in hundreds of fatalities and very substantial damage to facilities. The present work developed a fully coupled model capable of simulating spontaneous coal combustion and carbon monoxide (CO) release together with methane (CH4) desorption rates, concentration distributions and migration. The aim was to evaluate the combined hazard posed by spontaneous coal combustion and CH4 build-up in mine as a result of the heat release generated by coal oxidation. The results show that the zone representing the highest degree of compound hazard is in the shape of an inclined strip located between 75 and 115 m from the working face on the inlet airway side but closer to the working face on the return airway side. Increases in the CH4 concentration in the return corner decrease as the ventilation flux increases, while the potential danger zone moves deeper into the gob. A greater initial CH4 release rate from the coal increases the size of the danger zone and moves this zone closer to the working face. The danger zone also moves away from the working face with decreases in the residual coal thickness and in the coal oxidation rate. Multivariate functions were developed to predict the positions of the gas explosive zone and the oxidation zone in the gob, and a model for assessing the risk of the compound hazard was established based on evaluating the index gas concentrations in the return corner.

In this study, 95 accessions of proso millet (Panicum miliaceum L.) were characterized for starch physicochemical properties, including apparent amylose content (AAC), gel textural properties, Rapid Visco Analyzer (RVA) pasting viscosity properties, thermal and retrogradation properties. Based on genotypic data, the genetic diversity and inter-relationship of these starch traits were analyzed. Diverse starch quality was found, for example, AAC ranged from 0 to 32.3%, gelatinization temperature (GT) varied from 71.5 to 79.0 ℃, and RVA profile showed distinct patterns among proso millet of different AAC types. Interestingly, high AAC proso millet usually had GT lower than that of low AAC proso millet, which is different from the findings in rice starch. Many starch traits were significantly correlated and most of the 18 tested traits could be classified as either AAC-related traits or GT-related traits. In summary, the information presented here will be useful for further development of proso millet products.

Potential toxic metal(loid)s (PTMs) in road dust are a major concern in relation to urban environmental quality. Identifying pollution hotspots and sources of PTMs is an essential prerequisite for pollution control and management. Herein, the concentrations, pollution and potential health risks of 8 PTMs (As, Cd, Co, Cu, Hg, Mo, Pb and Zn) in road dust from the highly urbanized areas of Nanjing were studied. Spatial occurrences and sources of PTMs were explored using geostatistics, principal component analysis (PCA) and local Moran’s index. The contamination factor (CF) results showed that Co was mainly natural in origin, while the other PTMs were polluted, with average CFs ranging from 1.4 to 11.0 as follows: Hg > Mo > Cd > Cu > Pb > Zn > As, indicating moderate to very high contamination. Except for Co and Hg, the other PTMs were heavily loaded on PC1, which explained 44.72% of the total variance. Combining the statistical results and distributions of potential sources, we deduced that industrial emissions dominated the spatial patterns of all polluted PTMs in road dust, which showed high levels in the northern parts of the study region and generally decreasing levels southwards. Moreover, Pb and Zn in the south-central area and Cd in the north-central area displayed hotspots, with maximum CFs of 5.5 (Pb), 4.2 (Zn) and 16.2 (Cd), which were related to additional automotive and railway braking emissions, respectively. The resuspension of legacy pesticides in soil is likely responsible for the As pollution hotspot in the southwestern part. Despite the high anthropogenic contributions (27% for As and 68–88% for the other metals) to the PTMs in road dust, their noncarcinogenic and carcinogenic health risks were rarely found for children and adults based on the values of the hazard index and carcinogenic risk index. However, attention still should be paid to the pollution hotspots in the northern region.

In this study, starch was isolated from 13 genotypes of 12 Lycoris species, and the morphology, granule size distribution and physicochemical properties, including apparent amylose content (AAC), Rapid Visco Analyzer (RVA) pasting properties, textural properties, thermal and retrogradation properties were characterized. The majority of starch granules of the 13 Lycoris genotypes were oval in shape, and granule size followed a normal distribution with a mean diameter of 20–30 μm. Contrary to previously published findings, the XRD results revealed that lycoris starches had either C-type or CA-type crystallinity. All lycoris starches showed high AAC varying from 25.6% to 32.7%, and low gelatinization temperature (GT) ranging from 58.8 to 69.7 ℃. Inter-relationships among 18 starch quality traits were analyzed based on correlation analysis. The present study provides information on lycoris starch characteristics which should serve as a useful guide for later studies on lycoris starch utilization in food and non-food industries.

When the airfoil is working, the geometry of the channel that the fluid flows through changes with the airfoil profile. It makes the magnitude and direction of the velocity change, and resulting in flow separation. The impact produced by flow separation causes the loss of the flow's energy. This paper takes the blade of G4-73No.8D centrifugal fan as the research object. The flow and aerodynamic characteristics of the blades under different incidence angles are analyzed and researched by means of CFD. The slotted technique on centrifugal fan blade with slots cut along the blades pressure side to suction side is adopted. And slotted blade models data are compared with generic models. The results show that the method to create a slot in blade can control the stall of centrifugal fan flow passage availably. And under the appropriate parameters, slotted model can decrease the blade surface resistance and increase lift force effectively. Slotted model also has a role of control and mitigation of boundary layer separation, improving blade aerodynamic performance observably. The slot plays a similar role as the balancing hole, and make the high pressure low speed fluid flow into low-pressure side where the fluid is accelerated and has no extra energy be consumed. The research shows that slotted technique on centrifugal fan blade is useful to improve the characteristics of blade surface flow field, resulting in significant energy saving.

By using statistical analysis on the input and output of agricultural production, the intensity change in cultivated land use in Shandong province is analyzed. The results show that the multiple-cropping index is declining in recent years, and labor intensity is decreasing sharply while capital intensity is rising rapidly. From 1980 to 2010, the average annual growth rate of net income of main crops in Shandong province is 6.4%. The average level of land productivity is higher in economic crops than grain crops while the average level of labor productivity is higher in grain crops than economic crops. Land productivity has an obvious acceleration on farmer labor productivity. This has an important reference value for sustainable utilization of cultivated land in Shandong province.