Meteorological Change and Impacts on Air Pollution: Results From North China

There have been speculations that the severe air pollution experienced in North China was the act of meteorological change in general and a decreasing northerly wind in particular. We conduct a retrospective analysis on 1979–2016 reanalysis data from ERA‐Interim of European Centre for Medium‐Range Weather Forecasts over a region in North China to detect meteorological changes over the 38 years. No significant reduction in the northerly wind within the mixing layer is detected. Statistically significant increases are detected in the surface temperature, boundary layer height and dissipation, and significant decreases in relative humidity in the region between the first and second 19‐year periods from 1979 to 2016. We build regression models of PM2.5 on the meteorological variables using data in 2014, 2015, and 2016 to quantify effects of the meteorological changes between the two 19‐year periods on PM2.5 under the emission scenarios of 2014–2016. It is found that despite the warming, dew point temperature had been largely kept under control as the region had gotten dryer. This made the effects of temperature warming largely favorable to PM2.5 reduction as it enhances boundary layer height and dissipation. It is found that the meteorological changes would lead to 1.29% to 2.76% reduction in annual PM2.5 averages with January, March, and December having more than 4% reduction in the 3 years. Thus, the meteorological change in North China had helped alleviate PM2.5 to certain extent and should not be held responsible for the regional air pollution problem.Key PointsMeteorological changes led to 1.9% to 2.7 percent% reduction in annual PM2.5 averages over North China 2014 to 2016 driven by temperature warmingSignificant increases are detected in the surface temperature, boundary layer height, and dissipation and decreases in relative humidityThe meteorological change should not be held responsible for the regional air pollution problem in North ChinaPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156450/3/jgrd56226_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156450/2/jgrd56226.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156450/1/jgrd56226-sup-0001-Figure_SI-S01.pd

YOLO-FaceV2: A Scale and Occlusion Aware Face Detector

In recent years, face detection algorithms based on deep learning have made great progress. These algorithms can be generally divided into two categories, i.e. two-stage detector like Faster R-CNN and one-stage detector like YOLO. Because of the better balance between accuracy and speed, one-stage detectors have been widely used in many applications. In this paper, we propose a real-time face detector based on the one-stage detector YOLOv5, named YOLO-FaceV2. We design a Receptive Field Enhancement module called RFE to enhance receptive field of small face, and use NWD Loss to make up for the sensitivity of IoU to the location deviation of tiny objects. For face occlusion, we present an attention module named SEAM and introduce Repulsion Loss to solve it. Moreover, we use a weight function Slide to solve the imbalance between easy and hard samples and use the information of the effective receptive field to design the anchor. The experimental results on WiderFace dataset show that our face detector outperforms YOLO and its variants can be find in all easy, medium and hard subsets. Source code in https://github.com/Krasjet-Yu/YOLO-FaceV

Thermal management performances of PCM/water cooling-plate using for lithium-ion battery module based on non-uniform internal heat source

In order to improve the working performance of the lithium-ion battery, the battery module with Phase change material/water cooling-plate was designed and numerically analyzed based on the energy conservation and fluid dynamics. The non-uniform internal heat source based on 2D electro-thermal model for battery LiFePO4/C was used to simulate the heat generation of each battery. Then factors such as height of water cooling-plate, space between adjacent batteries, inlet mass flow rate, flow direction, thermal conductivity and melting point of PCM were discussed to research their influences on the cooling performance of module. And the 5 continuous charge-discharge cycles was used to research the effect of PCM/water cooling plate on preventing thermal runaway. The results showed that the water cooling plate set close to the near-electrode area of battery removed the majority of heat generated during discharging and decreased the maximum temperature efficiently. The PCM between the adjacent batteries could improve the uniformity of temperature field. In addition, the PCM/water cooling plate could limit the maximum temperature effectively and improve the uniformity of temperature field during the 5 continuous charge-discharge cycles. As a result, it prevented the emergence of thermal runaway and increased the safety of module. (C) 2017 Elsevier Ltd. All rights reserved

Investigation of thermal management for lithium-ion pouch battery module based on phase change slurry and mini channel cooling plate

In this paper, the thermal management based on phase change slurry (PCS) and mini channel cooling plate for the lithium-ion pouch battery module was proposed. The three-dimensional thermal model was established and the optimum structure of the cooling plate with mini channel was designed with the orthogonal matrix experimental method to balance the cooling performance and energy consumption. The simulation results showed that the cooling performance of PCS consisting of 20% n-octadecane microcapsules and 80% water was better than that of pure water, glycol solution and mineral oil, when the mass flow rate was less than 3 x 10(-4) kg s(-1). For different concentrations of PCS, if the mass flow rate exceeded the critical value, its cooling performance was worse than that of pure water. When the cooling target for battery maximum temperature was higher than 309 K, the PCS cooling with appropriate microcapsule concentration had the edge over in energy consumption compared with water cooling. At last, the dimensionless empirical formula was obtained to predict the effect of the PCS's physical parameters and flow characteristics on the heat transfer and cooling performance. The simulation results will be useful for the design of PCS based battery thermal management systems. (C) 2018 Elsevier Ltd. All rights reserved

Novel and predominant pathogen responsible for the enterovirus-associated encephalitis in eastern China

Enteroviruses (EV) have been increasingly identified as the causative agent for unknown etiological encephalitis in many parts of the world, but the long period surveillance for enterovirus-associated encephalitis (EAE) was not reported in China. From 2002-2012 in Zhejiang, Coxsackieviruses A9, B1, B2, B3, B4, B5; and echoviruses 3, 4, 6, 9, 14, 25, 30 were detected from the unknown etiological encephalitis cases, with coxsackievirus B4 been identified here for the first time. From 2002-2004 and 2010-2012, echovirus 30 was found to be the periodically predominant serotype for in the EAE. The molecular typing results showed that all the EV isolates from this study belonged to the human EV B (HEV B) family and were distributed in three clusters

Analysis of Aroma Characteristics of Fermented Lingyun Baihao Tea Based on Odor Activity Value

This study aimed to analyze the difference in aroma components and aroma characteristics of different types (white, oolong, yellow and black) of fermented Lingyun Baihao tea. The aroma components were identified by solid phase microextraction (SPME) combined with gas chromatography-mass spectrometry (GC-MS), and odor activity value (OAV) was used to determine the key flavor components. By combined use of principal component analysis (PCA), orthogonal partial least square-discriminant analysis (OPLS-DA), cluster analysis and sensory evaluation, the aroma of fermented Lingyun baihao tea was comprehensively evaluated. The results showed that a total of 48 aroma compounds were identified in the tea samples, including 15 key flavor components and flavor-modifying components (OAV > 0.1). The cumulative interpretation rate R2X (cum) and the cumulative prediction rate Q2 (cum) of the PCA model were 0.984 and 0.846, respectively, and those of the OPLS-DA model were greater than 0.7 and 0.9, respectively. Both models had good fitness. The major differential components were linalool, isoamyl alcohol, 2-methylbutyraldehyde, β-ionone, nonanal and jasmone. The 15 aroma components were classified into three categories by hierarchical cluster analysis (HCA). Class I contained indole and dehydroalinalool, Class II contained linalool, nonanal, phenylacetaldehyde, hexanal, 2-methylbutyraldehyde, isovaleraldehyde, phenylethanol and isobutyraldehyde, and Class III contained jasmone, β-ionone, methyl salicylate, 2-pentylfuran and dimethyl sulfide. Class I was prominent in oolong tea samples, Class II was prominent in black tea samples, Class III was prominent in white tea samples, and Class II and III were prominent in yellow tea samples. These aroma characteristics were consistent with the results of sensory aroma evaluation. GC-MS analysis and OAV calculation combined with PCA, OPLS-DA and HCA can enable the identification and evaluation of Lingyun Baihao fermented tea aroma. The results of this study can provide a reference for the further development of Lingyun Baihao tea

Compounds purified from edible fungi fight against chronic inflammation through oxidative stress regulation

Chronic inflammation is associated with various chronic diseases, including cardiovascular disease, neurodegenerative disease, and cancer, which severely affect the health and quality of life of people. Oxidative stress induced by unbalanced production and elimination of reactive oxygen species (ROS) is one of the essential risk factors for chronic inflammation. Recent studies, including the studies of mushrooms, which have received considerable attention, report that the antioxidant effects of natural compounds have more advantages than synthetic antioxidants. Mushrooms have been consumed by humans as precious nourishment for 3,000 years, and so far, more than 350 types have been identified in China. Mushrooms are rich in polysaccharides, peptides, polyphenols, alkaloids, and terpenoids and are associated with several healthy biological functions, especially antioxidant properties. As such, the extracts purified from mushrooms could activate the expression of antioxidant enzymes through the Keap1/Nrf2/ARE pathway to neutralize excessive ROS and inhibit ROS-induced chronic inflammation through the NF-κB pathway. Recently, the antioxidant properties of mushrooms have been successfully applied to treating cardiovascular disease (CAD), neurodegenerative diseases, diabetes mellitus, and cancer. The present review summarizes the antioxidant properties and the mechanism of compounds purified from mushrooms, emphasizing the oxidative stress regulation of mushrooms to fight against chronic inflammation