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Iris segmentation is one of the most important steps in iris recognition. The current iris segmentation network is based on convolutional neural network (CNN). Among these methods, there are still problems with the segmentation networks such as high complexity, insufficient accuracy, etc. To solve these problems, an improved low complexity DenseUnet is proposed to this paper based on U-net for acquiring a high-accuracy iris segmentation network. In this network, the improvements are as follows: (1) Design a dense block module that contains five convolutional layers and all convolutions are dilated convolutions aimed at enhancing feature extraction; (2) Except for the last convolutional layer, all convolutional layers output feature maps are set to the number 64, and this operation is to reduce the amounts of parameters without affecting the segmentation accuracy; (3) The solution proposed to this paper has low complexity and provides the possibility for the deployment of portable mobile devices. DenseUnet is used on the dataset of IITD, CASIA V4.0 and UBIRIS V2.0 during the experimental stage. The results of the experiments have shown that the iris segmentation network proposed in this paper has a better performance than existing algorithms.

Visibility observed at different altitudes is favorable to understand the causes of air pollution. We conducted 4-years of observations of visibility at 2.8 and 60 m and particulate matter (PM) concentrations from 2015 to 2018 in Shenyang, a provincial city in Northeast China. The results indicated that visibility increased with the increasing height in winter (especially at night), and decreased with height in summer (especially at the daytime). PM concentration exhibited opposite vertical variation to visibility, reflecting that visibility degrades with the increase of aerosol concentration in the air. The radiosonde meteorological data showed that weak turbulence in the planetary boundary layer (PBL) in winter favored aerosols’ accumulation near the surface. Whereas in summer, unstable atmospheric conditions, upper-level moister environment, and regional transport of air pollutants resulted in the deterioration of upper-level visibility. Inter-annual variation in the two-level visibility indicated that the upper-level visibility improved more significantly than low-level visibility, much likely due to the reduction in emission of elevated point sources in Shenyang. Our study suggested that strengthening the control of surface non-point emissions is a promising control strategy to improve Shenyang air quality.

The major constituents of sand are silica and silicates. The facile and low-cost purification technology of silica from natural sand is of magnificent importance to the industrial applications of silicon-based materials. Herein, we report a green, low-cost, and universal method to purify silica from natural sand. Sand from deserts, rivers, and seas is selected as the representative of natural sand. The initial purity of silica is 52.1 wt% for desert sand, 39.3 wt% for river sand, and 35.8 wt% for sea sand. High-purity silica has been successfully separated and purified from natural sand via ball milling, reacting with 30 bar CO2 and hydrochloric acid. The purity of silica derived from natural sand reaches >96 wt%. In this work, the mechanism for the purification of silica from natural sand is discussed. This study provides a new method to separate high-purity silica from natural sand without the generation of toxic and harmful substances.

Fluid catalytic cracking (FCC) is an important process in petroleum processing. Effective monitoring of the status and quality of FCC is vital. Accurate description of the relationship between process and quality variables is the basis of quality-driven monitoring. Many process variables affect the quality of FCC; some of these effects are linear, and others are nonlinear. We propose a combination method from the perspective of linearity and nonlinearity to improve the monitoring performance of FCC quality. Partial least squares (PLS) is initially used to extract linear features, and its residual space is saved as the input of the deep feedforward neural network (DFNN). DFNN is then used to extract nonlinear features for the further decomposition of subspaces. The PLS-DFNN method accurately describes processes involving linearity and nonlinearity. We construct three monitoring statistics to characterize the types of faults. The proposed method proves its excellent effect on a numerical simulation data set. It effectively distinguishes the types of faults on the Tennessee Eastman process data set, and the fault detection rate is superior to other related methods. Finally, we apply this method to the actual FCC and verify the superiority of this combination.

Northeastern China (NEC) has experienced serious environmental problems by energy consumption and domestic emission. This paper reviews an extreme haze event occurred in Shenyang, NEC, on 5–9 January 2017. The meteorological data, extinction coefficients from ground-based Lidar and aerosol optical products from Moderate Resolution Imaging Spectroradiometer (MODIS) were used to study this pollution evolution. The deterioration of visibility lasted for 57 h with a minimum value reached to 0.2 km. The SO2 decreased slightly to approximately 150 μg/m3 while the NO2 mass concentration increased to approximately 100 μg/m3. The northeastern wind (1–2 m/s) and higher relative humidity (RH) (90%) as well as increased pressure (1020 hPa) were conducive to particulate matter (PM) accumulation and degraded visibility. An inversion layer began to appear at 0.2 km and developed upward to 2.0 km with the development of heavy pollution, and the RH in the ground and upper air both increased significantly to 80%–90% to conducive larger aerosol extinction. The aerosol extinction coefficient increased to 1.7–1.8 km−1 during the serious pollution, and the average aerosol optical depth (AOD) increased to 1.5 with a larger Angstrom exponent (AE) increasing to 1.5 on 7 January. Five main clusters of air trajectories indicated that pollutants from the northwest, southwest, and local emissions affected Shenyang. These findings elucidate the coordinated variation in visibility, PM, and meteorology elements in the near and upper surfaces as well as the spatial distribution in aerosols from satellites during the special pollution episode in NEC.

With the rapid development of economy and urbanization acceleration, ozone (O3) pollution has become the main factor of urban air pollution in China after particulate matter. In this study, 90th percentile of maximum daily average (MDA) 8 h O3 (O3-8h-90per) and PM2.5 data from the Tracking Air Pollution in China (TAP) dataset were used to determine the mean annual, seasonal, monthly, and interannual distribution of O3-8h-90per and PM2.5 concentrations in Northeast China (NEC). The O3-8h-90per concentration was highest in Liaoning (>100 μg/m3), whereas the highest PM2.5 concentration was observed mainly in urban areas of central Liaoning and the Harbin–Changchun urban agglomeration (approximately 60 μg/m3). The O3-8h-90per concentrations were highest in spring and summer due to more intense solar radiation. On the contrary, the PM2.5 concentration increased considerably in winter influenced by anthropogenic activities. In May and June, the highest monthly mean O3-8h-90per concentrations were observed in central and western Liaoning, about 170–180 μg/m3, while the PM2.5 concentrations were the highest in January, February, and December, approximately 100 μg/m3. The annual mean O3-8h-90per concentration in NEC showed an increasing trend, while the PM2.5 concentration exhibited an annual decline. By 2020, the annual mean O3-8h-90per concentration in southern Liaoning had increased considerably, reaching 120–130 μg/m3. From the perspective of city levels, PM2.5 and O3-8h-90per also showed an opposite variation trend in the 35 cities of NEC. The reduced tropospheric NO2 column is consistent with the decreasing trend of the interannual PM2.5, while the increased surface temperature could be the main meteorological factor affecting the O3-8h-90per concentration in NEC. The results of this study enable a comprehensive understanding of the regional and climatological O3-8h-90per and PM2.5 distribution at distinct spatial and temporal scales in NEC.

Purpose miR-497-5p can inhibit cervical cancer cell proliferation. However, the underlying mechanism remains to be elucidated. Methods Bioinformatics was used to analyze the target genes of miR-497-5p. qRT-PCR and Western blot were used to analyze mRNA and protein expression, respectively. Dual-luciferase reporter assay was used to analyze the direct binding between miR-497-5p and 3'-untranslated region of CBX4. Cell viability was measured with MTT assay. Flow cytometry was performed to detect cell cycle distribution. Results Here, using bioinformatics methods we firstly found that miR-497-5p regulated cervical carcinoma proliferation by targeting polycomb chromobox4 (CBX4). Expression of miR-497-5p in cervical carcinoma tissues was negatively correlated with CBX4. A binding region of miR-497-5p in 3'-untranslated region of CBX4 was predicted. Further experiments confirmed that miR-497-5p directly targeted CBX4. Besides, RNA interference of CBX4 inhibited cervical cancer cell proliferation, arrested cells at S phase and reduced the expression of CDK2 and Cyclin A2 proteins. The use of miR-497-5p inhibitor compromised CBX4 interference RNAs induced cycle arrest of cervical cancer cells. Cells co-transfected with miR-497-5p inhibitors and CBX4 interference RNAs had a higher proliferation rate than CBX4 inference RNA-transfected cells. Conclusion All together, the present study demonstrates that miR-497-5p inhibits cervical cancer cells proliferation by directly targeting CBX4.

Based on the simultaneous observation of fine particulate matter (PM2.5) and its chemical components in four heavy haze pollution episodes at 14 sampling sites in northeast China from 2017 to 2019, the formation and existence of sulfate (SO42-) and nitrate (NO3-) secondary contaminants under different stages of the pollution episodes, and different meteorological and emission conditions were compared. The results yielded three main findings. (1) Organic carbon (OC) was the most important component of PM2.5, followed by NO3-,SO42-,and ammonium (NH4+). Nitrate surpassed sulfate as the most important secondary inorganic component over the study period. (2) The significant increase in atmospheric OC, SO42-, and NO3-concentrations was an important reason for haze formation. Meteorological factors such as wind direction, wind speed, temperature (T), relative humidity (RH), and atmospheric oxidability played an important role in secondary pollutant formation. (3) There were two potential SO42- formation mechanisms. The first was the gas-phase reaction of the hydroxyl radical(OH·) leading to the oxidation of nitrogen dioxide (NO2) and sulfur dioxide (SO2),and high ozone (O3) concentrations. A high atmospheric oxidability and high winter Ts were very important for SO42- formation. The second mechanism occurred under neutral or weakly alkaline conditions when large amounts of SO2 could enter aerosol droplets, and NO2 was more likely to react in the aqueous phase with SO2 to increase the output of SO42-. Nitrate formation was may be mainly due to the homogeneous gas-phase reaction of OH· with NO2, SO2, and ammonia(NH3). The highest NO3 concentration was observed under mild winter Ts, high RH, high atmospheric oxidability (O3 and nitrous acid (HONO)), high NH3 concentrations, and suitable light conditions. The differences in SO42- formation between northeast China and other regions were mainly a result of the suppression of the aqueous reaction of SO42- due to the low T in winter and low-sulfur coal emissions, which resulted in the gas-phase oxidation process with the highest SO42- production capacity becoming an important process. However, the aqueous reaction process was the most common mechanism of SO42- production in northeast China.

The formation and evolution of sulfate (SO

The technologies of two-dimensional sound source localization based on diaphragm extrinsic Fabry–Perot interferometer (EFPI) fiber microphone array have been studied in this paper. The fiber microphone array consists of three EFPI. Self-calibrated intensity demodulation technology with simple structure and low cost is adopted to demodulate the sound signals. Using effective sound signal extraction technology to find the starting point and end point of sound signal, combining with time differences of arrival (TDOA) positioning technology, high-precision sound source location is successfully realized. The average positioning error of this system is no larger than 4.82%. The system has the advantages of low cost, high practicability and wide application scenarios.

Atmospheric aerosol levels are high in different regions of China. Changes in atmospheric stability and mixing layer height (MLH) may affect the vertical aerosol distribution during pollution events. Here, we continuous studied the spatiotemporal distribution of MLH in China over 2000–2013 to characterize the regional-scale properties of atmospheric boundary layers. MLH was larger in the Southern Coastal and Southeastern China (1241.5 ± 73.5 and 632.7 ± 61.8 m, respectively), but lower in Eastern and Southwestern China (518.1 ± 63.6 and 462.7 ± 88.5 m, respectively). We divided the monitoring stations into 11 regions; these regions could be classified into three types with an increasing linear trend (95% confidence level), with a decreasing linear trend (95% confidence level), and with fluctuation changes. In all regions, MLH was higher in spring and summer than in autumn and winter. The spatial distribution of the diurnal MLH increased significantly at 1400 BJT (Beijing time) in all regions, with the strongest radiation being noted during the daytime. Higher levels of PM2.5 with corresponding lower MLH were noted during winter, indicating that lower MLH could confine the pollutant diffusion to near the surface. By contrast, in spring, higher MLH could be potentially due to the dynamic condition. In general, the poor air quality days occurred more frequently in winter than in other seasons. As the air quality worsened, most MLH showed a decreasing trend in almost all regions. This work provides information that aids in further understanding not only MLH distribution in China but also specific PM–MLH interaction to facilitate regional atmospheric environment monitoring and prediction.

From January 1 to April 22, 2014, an online analyzer for monitoring aerosols and gases (MARGA) was used to measure and analyze water-soluble ions in inhalable particulate matter with a diameter less than 10 μm (PM10) during winter-spring in Shenyang city, China. The results yielded three main findings. (1) During the entire observation period and in seven pollution episodes, SO42−, NO3−, and NH4+ (SNA) accounted for 84.4–93.1% of the total water-soluble ions (TWSIs). TWSIs accounted for 32% of PM10 mass during the entire observation period, and the contribution of TWSIs in PM10 ranged from 33.4–43.1% in the seven pollution episodes. The contribution of TWSIs components increased during the pollution episodes, but certain differences were observed in different pollution episodes. In terms of ionic equilibrium, the total concentration of negative ions was slightly greater than that of positive ions and the difference was 3.1% of the total ion load on average, indicating that local aerosols are mainly neutral. The water-soluble ions show clear diurnal variation with the high concentration around 09:00 for SO42−, NH4+, and Cl− which is consistent with the high heating grade index. (2) Pollution episodes often occur in Northeast China, especially during the winter period. Due to the low temperature in the winter, the local coal burning for heating is one of the main sources of pollution besides vehicle exhaust and industrial pollution, which is supported by the higher NO3−/SO42− ratio in April than that in January to March. Sometimes, under the prevailing wind directions of W and SSW, the long-distance transport of pollutants from the Beijing-Tianjin-Hebei region and Shandong province superimposed on local pollution leads to the most severe pollution, such as Ep3 and Ep5. (3) SO42− concentration is closely related to ambient water vapor pressure (e*), with increase as e* increased depending on the temperature. NO3− concentration showed a linear relationship of excess NH4+, which suggests homogeneous gas-phase reaction of ammonia and nitric acid is possibly an important pathways of nitrate formation in the haze pollution process in Shenyang City. In addition, our results also suggest the nighttime liquid-phase reaction may cause large increases of nitrate in the haze pollution process.

The impact of the planetary boundary layer (PBL) structure on the vertical distribution of aerosols in Northeast China, which experiences air pollution frequently in autumn and winter, is not well understood. We investigated the characteristics of the vertical distribution of particulate matter (PM1, PM2.5, and PM10) mass concentrations and their relationships with PBL structures in Shenyang, a provincial capital city in Northeast China, using balloon sounding data collected during an intensive observation period in November 2018. Aerosols typically decreased with increases in height and were mostly distributed below 400 m at night and reached higher altitudes (~800 m) in the daytime due to convective turbulence. The concentration ratios of PM1/PM2.5 and PM2.5/PM10 measured about 0.6 and 0.8, respectively, below 0.6–1.0 km during the daytime, and below 0.5 km at nighttime. On average, stronger atmospheric stability resulted in greater vertical gradients and higher PM concentrations near the surface. During four air pollution episodes (November 1–4, 7–10, 14–15, and 25–27), when atmospheric stability was strong at night, aerosols tended to remain in a shallow stable surface layer (< 300 m) and at the bottom of a residual layer (250–500 m) due to weak vertical mixing. After sunrise, these aerosols were mixed uniformly in the PBL (the depth increasing from 200 m to more than 1 km), subsequently affecting surface air quality. In addition, strong wind speeds and wind shears caused by nocturnal low-level jets and cold front systems influenced the formation and evolution of air pollution episodes. These processes controlled aerosol transport/dispersion processes and can modify atmospheric stability and PBL height. These results have important implications for understanding the vertical distribution of aerosols, and the crucial roles that PBL structures play in modulating aerosol pollution in Shenyang.

The size-resolved hygroscopic properties of submicron particles were observed by a Hygroscopicity Tandem Differential Mobility Analyzer (HTDMA) at an urban site in Beijing in December 2016. HTDMA was operated at the relative humidity (RH) of 30–90% with the particle size range of 30–200 nm. The probability distribution of the hygroscopic growth factor (HGF-PDF) during the measurement usually showed a bimodal pattern, namely, hydrophobic mode (HGF

Objective: This study was conducted to evaluate the acute and subchronic toxicity of gardenia yellow, a natural colorant widely used in China and other Asian countries. An acute toxicity test was performed in S-D rats of both genders and the lethal dose (LD50) of per oral gardenia yellow was estimated to be more than 15.0 g/kg&middot, bw. In the subchronic study, gardenia yellow was orally administered to rats by gavage at doses of 0, 0.50, 1.50 and 4.50 g/kg&middot, bw/day for 90 days followed by a recovery period of 28 days. No appreciable toxic-related changes were observed in the 0.50 g/kg&middot, bw/day group. When the animals received gardenia yellow at 1.50 g/kg&middot, bw/day or more, body weight loss was observed, and pigments began to deposit in several vital organs, resulting in significant changes of several hematological and biochemical indicators related to the nutritional status of the body, liver and kidney function, more severe in the high dose group. In the recovery period, the alterations of the clinical symptoms and parameters were relieved a lot. Based on the results of the current study, the no observed adverse effect level (NOAEL) of gardenia yellow E500 in rats was set to be 0.50 g/kg&middot, bw/day.

This study analyzes and compares aerosol properties and meteorological conditions during two air pollution episodes in 19–22 (E1) and 25–26 (E2) December 2016 in Northeast China. The visibility, particulate matter (PM) mass concentration, and surface meteorological observations were examined, together with the planetary boundary layer (PBL) properties and vertical profiles of aerosol extinction coefficient and volume depolarization ratio that were measured by a ground-based lidar in Shenyang of Liaoning Province, China during December 2016–January 2017. Results suggest that the low PBL height led to poor pollution dilution in E1, while the high PBL accompanied by low visibility in E2 might have been due to cross-regional and vertical air transmission. The PM mass concentration decreased as the PBL height increased in E1 while these two variables were positively correlated in E2. The enhanced winds in E2 diffused the pollutants and contributed largely to the aerosol transport. Strong temperature inversion in E1 resulted in increased PM2.5 and PM10 concentrations, and the winds in E2 favoured the southwesterly transport of aerosols from the North China Plain into the region surrounding Shenyang. The large extinction coefficient was partially attributed to the local pollution under the low PBL with high ground-surface PM mass concentrations in E1, whereas the cross-regional transport of aerosols within a high PBL and the low PM mass concentration near the ground in E2 were associated with severe aerosol extinction at high altitudes. These results may facilitate better understanding of the vertical distribution of aerosol properties during winter pollution events in Northeast China.

The characteristics of boundary layer structure during a persistent regional haze event over the central Liaoning city cluster of Northeast China from 16 to 21 December 2016 were investigated based on the measurements of particulate matter (PM) concentration and the meteorological data within the atmospheric boundary layer (ABL). During the observational period, the maximum hourly mean PM2.5 and PM10 concentrations in Shenyang, Anshan, Fushun, and Benxi ranged from 276 to 355 μg m–3 and from 378 to 442 μg m–3, respectively, and the lowest hourly mean atmospheric visibility (VIS) in different cities ranged from 0.14 to 0.64 km. The central Liaoning city cluster was located in the front of a slowly moving high pressure and was mainly controlled by southerly winds. Wind speed (WS) within the ABL (< 2 km) decreased significantly and WS at 10-m height mostly remained below 2 m s–1 during the hazy episodes, which was favorable for the accumulation of air pollutants. A potential temperature inversion layer existed throughout the entire ABL during the earlier hazy episode from 0500 Local Time (LT) 18 December to 1100 LT 19 December, and then a potential temperature inversion layer developed with the bottom gradually decreased from 900 m to 300 m. Such a stable atmospheric stratification further weakened pollutant dispersion. The atmospheric boundary layer height (ABLH) estimated based on potential temperature profiles was mostly lower than 400 m and varied oppositely with PM2.5 in Shenyang. In summary, weak winds due to calm synoptic conditions, strong thermal inversion layer, and shallow atmospheric boundary layer contributed to the formation and development of this haze event. The backward trajectory analysis revealed the sources of air masses and explained the different characteristics of the haze episodes in the four cities.

Many potential applications are developed towards the new memristive systems. However, these systems are too complicated to produce the real elements, the simplifications of memristive systems are interesting to our future applications. The simplest memristive system is modeled to make the real elements more practical in the electric circuit, which may confirm three fingerprints of memristor. These results verified by Matlab and Multisim simulations indicate that the proposed memristive system produces a pinched hysteresis loop for a periodic input. The voltage-current relation-ships are investigated for two parallel memristor circuits-a parallel memristor and capacitor circuit, and a parallel memristor and inductor circuit. It may be convenient and useful for our future application in the circuit.

The industrial city of Shenyang in northeastern China has undergone a period of rapid development; long-term aerosol vertical properties could be relevant to more clearly understanding local emissions and their regional transportation. Aerosol optical depth (AOD), planetary boundary layer (PBL) height, and the vertical profiles of extinction coefficient, were measured and analyzed with ground-based Lidar during 2016 in Shenyang. Ground-level particulate matter mass concentrations, meteorological parameters, backward trajectories, and Moderate Resolution Imaging Spectroradiometer products were used to study the pollutant sources in four cases using the potential source contribution function and concentration-weighted trajectory methods. The results indicate that the AOD was 0.10 ± 0.10 to 0.23 ± 0.34 from January to May, and approximately 0.49 ± 0.39 in July. The PBL height was highest in March (1318.7 ± 696.5 m) and lowest in winter (877.1 ± 508.1 m to 950.7 ± 762.3 m). The mass concentrations of PM10, PM2.5, and PM1.0 were highest in January at 148.2 ± 77.8 µg m–3, 106.0 ± 58.8 µg m–3, and 33.8 ± 20.5 µg m–3; and lowest in June at 56.2 ± 27.8 µg m–3, 33.7 ± 18.3 µg m–3, and 9.3 ± 6.0 µg m–3, respectively. The concentrations of SO2 and CO were higher in winter and lower in summer, whereas O3 concentrations were higher in summer and lower in winter. The monthly extinction coefficient was affected by dust events in spring and new particle generation in summer, as well as by biomass-burning and coal-burning emissions in autumn and winter. Four pollution sources—from northwestern, eastern, northern, and northeastern China—were selected to analyze the different paths and sources of pollutants affecting Shenyang. The results of this paper will be helpful in the study of continuous year-round aerosol vertical properties and the regional pollution features of northeast China.

Temporal and spatial characteristics of atmospheric particulate matter (PM10 and PM2.5) and its relationship with meteorology over Shenyang, a city in northeast China, were statistically analyzed using hourly and daily averaged PM mass concentrations measured at 11 locations and surface meteorological parameters, from January 2014 to May 2016. Using averaged data from 11 stations in Shenyang, it was found that the monthly mean PM2.5 mass concentrations were higher in winter (97.2 ± 11.2 μg m− 3) and autumn (85.5 ± 42.9 μg m− 3), and lower in spring (62.0 ± 14.0 μg m− 3) and summer (42.5 ± 8.4 μg m− 3), similar to the seasonal variation in PM10 concentrations. The monthly ratios of PM2.5/PM10 ranged from 0.41 to 0.87, and were larger in autumn and winter but lowest in spring due to dust activities. PM pollution was concentrated mainly in the central, northern, and western areas of Shenyang in most seasons mainly due to anthropogenic activities such as traffic and residential emission and construction activity as well as natural dust emission. PM concentrations observed over different areas in all seasons generally exhibited two peaks, at 08:00–10:00 local time (LT) and 21:00–23:00 LT, with the exception of PM2.5 in summer, which showed only one peak during the daytime. In addition, PM10 concentrations peaked around 14:00 LT during spring in the western area of Shenyang because of strong thermal and dynamic turbulence, resulting in elevated dust emissions from adjacent dust sources. The relationship between daily PM concentrations and meteorological parameters showed both seasonal and annual variation. Overall, both PM2.5 and PM10 concentrations were negatively correlated with atmospheric visibility, with correlation coefficients (R) of 0.71 and 0.56, respectively. In most seasons, PM concentrations also exhibited negative correlations with wind speed, but showed positive correlations with air pressure, air temperature, and relative humidity. Strong wind speed favored the dispersion of PM pollution, but also aided the release of coarse dust particles in spring. High air pressure and downdrafts restrained the upward movement of atmospheric PM, resulting in an accumulation of particles in the boundary layer. High air temperature favored the transformation of secondary particles through photochemical processes in summer, but also resulted in efficient vertical dispersion of pollutants in autumn and winter, leading to an inverse relationship between temperature and PM concentrations. Large relative humidity usually caused increases in PM concentrations due to the hygroscopic effect of aerosols, but not for PM10 in spring and summer, mainly due to the suppression of dust emissions under wet air conditions in spring and the effects of wet scavenging under high summer rainfall.

With the rapid development of science and technology, biotechnology has developed rapidly. Among the many biometric technologies, finger vein technology has the characteristics of vitality, portability, and non-replicability, so it is considered to be the most promising biometric technology. However, the accuracy of finger vein recognition is affected by the collection device, the surrounding temperature and the algorithm. The flaws cannot be applied to real life on a large scale. This paper designs a finger vein recognition system based on convolutional neural network and Android, which mainly includes the following three parts. First, the system hardware includes the design of the acquisition device, the selection of the core development board and the display screen. Second, the design of the entire system software architecture is based on the MVVM architecture, which ensures low coupling of the program and is easy for later expansion and maintenance. The software includes collection function, recognition function and administrator function. Finally, a lightweight neural network is proposed for finger vein feature extraction, and proposed a storage method based on MMKV to meet the real-time performance of the system.

Northeast China frequently experiences aerosol pollution episodes in winter. In addition to the pollutant emissions, synoptic pattern and topography can impact the air quality in complex ways, which are still not well understood in Northeast China. Therefore, the impacts of synoptic forcing and topography on aerosol pollution in Shenyang were investigated combining surface observations, sounding measurements, and three-dimensional air quality simulations. The studied pollution episode occurred from January 1 to 5, 2020, along with poor meteorological dispersion conditions characterized by weak winds, strong thermal stabilities, and shallow planetary boundary layers (PBLs). During the formation of pollution, strong elevated thermal inversion layers were observed over Shenyang, induced by the large-scale synoptic pattern, which suppressed the PBL growth and the vertical dispersion of aerosols. Moreover, the blocking effect of mountains to the east of Shenyang further worsened the pollution when northwesterly/westerly flows prevailed in shallow PBLs. Numerical sensitive experiment was conducted to estimate the contribution of blocking effect of mountains to the near-surface PM2.5 concentration in Shenyang, and it was found that around one third of PM2.5 concentration during January 1–4 was relevant to the terrain effect. These findings can facilitate a comprehensive understanding of the physical formation of aerosol pollution in Northeast China and helpful for the pollution controls.

The climatological variations of aerosol optical properties are significant in the study of aerosol effect on regional environment. The MODIS level 2 aerosol optical depth (AOD) products (MOD04/MYD04) at 10 km were used to identify the spatial distribution, interdecadal trends, and aerosol types from 2002 to 2019 in Liaoning province over Northeast China. The highest AOD was distributed in central Liaoning, with a peak value of approximately 0.6 and the fine mode fraction (FMF) was higher in eastern Liaoning about 0.8. The overall AOD for Liaoning in summer was significantly higher than that in other seasons, and the higher AOD values were observed in central Liaoning and the area around Bohai Rim (up to approximately 0.7). The frequency of 0.1 ≤ AOD 0.8, the cities were categorised into those with an increase frequency of 15% to 20%, and those with a decrease frequency of 5% to 10%. During 2014 to 2019, the interannual variation in AOD in Liaoning exhibited a significant downward trend, with a minimum AOD of approximately 0.25 in 2019. The FMF in Liaoning from 2002 to 2019 exhibited a fluctuating trend around 0.5. The AOD in Liaoning showed an increasing trend from 2002 to 2008 with a maximum of approximately 0.02/year and a clear decreasing trend from 2009 to 2019 of approximately −0.02/year. Maritime aerosol mostly occurred in cities in western Liaoning accounted for 20.58% to 36.52%. Dust aerosol had a considerable influence on central Liaoning accounting for 2.95% to 16.18%. In eastern Liaoning, continental background aerosol accounted for 36.69% to 43.30%. These results revealed the influence of AOD and fine particles on aerosol extinction in Northeast China and provided important information for the climate change in Northeast Asia.

Characteristics of ice nuclei (IN) number concentrations during three fog-haze weather periods from November 2010 to January 2012 in Shenyang were presented in this paper. A static diffusion chamber was used and sampling of IN aerosols was conducted using a membrane filter method. Sampling membrane filter processing conditions were unified in the activation temperature at − 15 °C under conditions of 20% ice supersaturation and 3% water supersaturation. The variations of natural IN number concentrations in different weather conditions were investigated. The relations between the meteorological factors and the IN number concentrations were analyzed, and relationships between pollutants and IN number concentrations were also studied. The results showed that mean IN number concentration were 38.68 L − 1 at − 20 °C in Shenyang, for all measurements. Mean IN number concentrations are higher during haze days (55.92 L − 1 at − 20 °C) and lower after rain. Of all meteorological factors, wind speed, boundary stability, and airflow direction appeared to influence IN number concentrations. IN number concentrations were positively correlated with particulate matters PM 1 , PM 2.5 , and PM 10 during haze weather.

The aerosol liquid water content (ALWC) of submicron particles (PM1) was calculated in this work by three methods based on the aerosol physical and chemical properties measurement campaigns in winter in Beijing, including (a) the PM1 volume difference between the ambient and dry states by applying the particle number size distribution and particle hygroscopicity measurement; (b) the thermodynamic equilibrium model (ISORROPIA II) based on the chemical composition; and (c) the κ-Kohler theory of chemical composition with a volume mixing scheme. The three methods agreed well with reasonable uncertainties. The ALWC showed an exponential trend depending on the relative humidity (RH), and an abundant ALWC was also favored by the high PM1 mass loading. The contribution of different chemical component to the ALWC was evaluated by the κ-Kohler method, which revealed that during the measurement, the inorganics and organics could contribute to ~80% and ~20%, respectively, under ambient RH conditions, with the largest contributor of ammonium nitrate. When the RH was above 85%, the mass concentration of ALWC was comparable to, or even larger than, that of the dry PM1.

Aerosol generated from the economic development and extensive urbanization in northeast China (NEC) could influence aerosol optical properties and affect the regional air quality. The level 3 aerosol optical depth (AOD) of different particle size and shape (spherical or nonspherical) obtained by Multiangle Imaging Spectroradiometer (MISR) version 23 were used to estimate their seasonal, annual, and decadal distribution and contribution in NEC from 2001 to 2018. The highest AOD of approximately 0.3 was found in the central Liaoning urban agglomeration, and the lowest AOD occurred in the mountainous area of NEC; the proportion of spherical AOD in NEC region was more than 90%. The contribution of large AOD was higher in spring, ranging from 28.8% to 29.8%. In spring and summer, small and medium AODs were concentrated in central Liaoning (approximately 0.2-0.3 and 0.06-0.08, respectively). The annual variation in the AOD of different particle size was significantly higher in Liaoning than in Jilin and Heilongjiang. The annual proportions of small and spherical AODs were approximately 60% and 90%, respectively. The annual occurrence of clean conditions with AOD 0.05 was most common in northern Heilongjiang (approximately 20%). In NEC, the annual occurrence frequencies of 0.05 AOD 0.15 and AOD 0.6 were the highest (approximately 50%) and the lowest (less than 1%), respectively. Interdecadal AOD revealed a positive trend from 2001 to 2008 and a negative trend from 2009 to 2018. The frequency of occurrence trend at different AOD levels also changed from positive to negative between these two periods. The findings in this study are based on the first aerosol retrieval of the newly released MISR in NEC. The results provide a comprehensive understanding of the regional and climatological aerosol extinction with different AOD of size and shape as well as various level bins in NEC.

An in-situ measurement of the particle number size distribution and optical properties (scattering and absorption coefficients) of PM2.5 was conducted at Mt. Tai, a mountain top station in central east China in the spring of 2011. It was found that the particle size distribution, mass concentration, as well as the optical properties have been modified during the dust periods. The mean mass concentration of PM2.5 during the dust periods was nearly twice of that during the non-dust period. The number and volume size distribution showed a higher concentration in the size range of 0.5–2.5 μm during the dust period, which were identified as dust particles. The absorption coefficient increased by ∼40%, while the scattering coefficient did not show much difference. The single scattering albedo of 0.85 during dust period was also comparable with the value of 0.89 during non-dust period. The Mie model was applied to simulate the aerosol optical properties and validated through a closure study for an intensive dust event. This study quantitatively demonstrated that dust particles contributed to nearly 63% of the scattering coefficient, while the remainder was mainly due to anthropogenic particles on dust days. The dust particles took a lower portion to the absorption, about 40%, indicating the anthropogenic particles still played a more dominant role in absorbing. This study also indicated that although there were only a few tens of dust particles during dust period, they could influence in particle optical properties significantly.

Visibility, particulate matter (PM) mass concentration, and aerosol optical properties data from June 2009 to December 2011 were obtained at Shenyang in Northeast China. The characteristics and relationships between these parameters were statistically analyzed. The results demonstrate that the monthly averaged visibility over Shenyang was higher in spring and autumn but lower in summer and winter, and had an inverse trend to PM and aerosol optical depth (AOD). Higher AOD at 500 nm was found year by year, with the maximum value (1.31 ± 0.45) occurring in June 2011, and the minimum in June 2010 (0.72 ± 0.31). The mean value of the Angstrom exponent underwent a notable reduction during the period of 2011, with values less than 1.0 from February to September. The single scattering albedo was consistently around 0.90 during 2009–2011, which was higher in summer but lower in winter. The higher absorption aerosol optical depth at 440 nm in 2011 indicates that there were more absorbing aerosol particles in this period compared with the corresponding absorption Angstrom exponent in the same year (about 0.75). The direct radiative forcing at the bottom of the atmosphere increased to − 200 W/m 2 in 2011, compared with − 150 W/m 2 from June 2009 to December 2010, suggesting a stronger cooling effect of aerosols at the surface. The positive radiative forcing at the top of the atmosphere in November and December 2009 could have been due to snow cover, which has a large surface albedo that reflects shortwave radiation to the atmosphere.

Air pollution is a critical urban environmental issue in China, however, the relationships between air pollutants and ecological functional zones in urban areas are poorly understood. Therefore, we analyzed the spatiotemporal characteristics of four major air pollutants (particulate matter less than or equal to 2.5 &micro, m (PM2.5) and 10 &micro, m (PM10) in diameter, SO2, and NO2) concentrations over five ecological functional zones in Shenyang, Liaoning Province, at hourly, seasonal, and annual scales using data collected from 11 monitoring stations over 2 years. We further assessed the relationships between these pollutants and meteorological conditions and land-use types at the local scale. Peaks in PM, SO2, and NO2 concentrations occurred at 08:00&ndash, 09:00 and 23:00 in all five zones. Daytime PM concentrations were highest in the industrial zone, and those of SO2 and NO2 were highest in residential areas. All four air pollutants reached their highest concentrations in winter and lowest in summer. The highest mean seasonal PM concentrations were found in the industrial zone, and the highest SO2 and NO2 concentrations were found in residential areas. The mean annual PM and SO2 concentrations decreased in 2017 in all zones, while that of NO2 increased in all zones excluding the cultural zone. The natural reserve zone had the lowest concentrations of all pollutants at all temporal scales. Pollutant concentrations of PM2.5, PM10, SO2, and NO2 were correlated with visibility, and their correlation coefficients are 0.675, 0.579, 0.475, and 0.477. Land coverage with buildings and natural vegetation negatively and positively influence air pollutant concentrations, respectively.

In the present study, a novel transgenic rice line T1c-19 carrying cry1C* gene was evaluated in Sprague-Dawley (SD) rats by a 52-week feeding study, aiming at determining its unintended effects. The rice T1c-19 and its parental rice were prepared at a level of up to 60.75% in the growth diet and 66.75% in the maintenance diet, respectively. AIN-93 diet was used as a nutritional control. All the diets were nutritionally balanced. Each group, with 48 rats of both genders, was fed the corresponding diet for 52 weeks. The results of clinical signs, body weight and food consumption of the transgenic rice group were comparable to those of the parental rice group. Clinical measurements were made on weeks 13, 26 and 52, and statistical significances were observed in several hematological and serum biochemical indices between the two rice groups and were not considered as treatment-related. The terminal histopathological examination showed some spontaneous lesions in all groups with no significant difference among them. Taken together, the results of the present 52-week chronic toxicity study of transgenic rice T1c-19 exerted no unintended adverse effects on SD rats.

Two planetary boundary layer schemes (YUS and MYJ) in the WRF-CMAQ model, are selected for sensitivity simulation, and the simulation capabilities of different planetary boundary layer schemes to meteorological elements and PM2.5 concentration distribution are analyzed from December 17th to December 20th in 2016. The results show that using the YSU and MYJ schemes can well simulate the spatial distribution and diurnal variation characteristics of temperature, wind speed and PM2.5 concentration on the ground under the background of stable weather in winter. It is sensitive to temperature, wind speed and PM2.5 concentration on the ground using different planetary boundary layer parameterization schemes. The simulated wind speed is relatively large, and the maximum deviation can reach about 2m/s. The deviation of wind speed using the MYJ scheme is relatively small than YSU, which is closer to the real value. There has a lower PM2.5 concentration value using YSU than MYJ at night, however the daytime (mainly from 11:00 to 18: 00) YSU scheme is relatively higher than MYJ. The deviation of PM2.5 concentration on the ground using the MYJ scheme is relatively smaller than YSU, and the characteristics of daily variation is closer to the real situation. Overall, the MYJ scheme is better than YSU in air pollution simulation.