The corrosion characteristic and mechanism of Mg-5Y-1.5Nd-xZn-0.5Zr(x=0,2,4,6 wt.%)alloys in marine atmospheric environment

The microstructure and precipitated phases of as-cast Mg-5Y-1.5Nd-x Zn-0.5Zr(x=0,2,4,6 wt.%)alloys were investigated by optical microscopy,scanning electron microscopy,energy-dispersive spectrometry and X-ray Diffraction.The exposure corrosion experiment of these magnesium alloys was tested in South China Sea and KEXUE vessel atmospheric environment.The corrosion characteristic and mechanism of magnesium alloys of Mg-5Y-1.5Nd-x Zn-0.5Zr(x=0,2,4,6 wt.%)alloys were analyzed by weight loss rate,corrosion depth,corrosion products and corrosion morphologies.The electrochemical corrosion tests were also measured in the natural seawater.The comprehensive results showed that Mg-5Y-1.5Nd-4Zn-0.5Zr magnesium alloy existed the best corrosion resistance whether in the marine atmospheric environment and natural seawater environment.That depended on the microstructure,type and distribution of precipitated phases in Mg-5Y-1.5Nd-4Zn-0.5Zr magnesium alloy.Sufficient quantity anodic precipitated phases in the microstructure of Mg-5Y-1.5Nd-4Zn-0.5Zr alloy played the key role in the corrosion resistance.

Developing an atmospheric aging evaluation model of acrylic coatings:A semi-supervised machine learning algorithm

To study the atmospheric aging of acrylic coatings,a two-year aging exposure experiment was conducted in 13 representative climatic environments in China.An atmospheric aging evaluation model of acrylic coatings was developed based on aging data including11 environmental factors from 567 cities.A hybrid method of random forest and Spearman correlation analysis was used to reduce the redundancy and multicollinearity of the data set by dimensionality reduction.A semi-supervised collaborative trained regression model was developed with the environmental factors as input and the low-frequency impedance modulus values of the electrochemical impedance spectra of acrylic coatings in 3.5wt%NaCl solution as output.The model improves accuracy compared to supervised learning algorithms model(support vector machines model).The model provides a new method for the rapid evaluation of the aging performance of acrylic coatings,and may also serve as a reference to evaluate the aging performance of other organic coatings.

Atmospheric Environmental Capacity of S_2 in Winter over Lanzhou in China:A Case Study

The total emission control method based on atmospheric environmental capacity is the most effective in air pollution mitigation. The atmospheric environmental capacities of SO2 on representative days over Lanzhou are estimated using the numerical models RAMS, HYPACT and a linear programming model, according to the national ambient air quality standard of China （NAAQSCHN）. The results show that the fields of meteorological elements and SO2 simulated by the models agree reasonably well with observations. The atmospheric environmental capacity of SO2 over Lanzhou is around 111.7 × 10^3 kg d^-1, and in order to meet the air quality level Ⅱ of the NAAQSCHN, SO2 emissions need to be reduced by 20%.

Radar-based Characteristics and Formation Environment of Supercells in the Landfalling Typhoon Mujigae in 2015

This study presents the radar-based characteristics and formation environment of supercells spawned by the tornadic landfalling Typhoon Mujigae(2015)in October 2015.More than 100 supercells were identified within a 24-hour period around the time of the typhoon’s landfall,of which three were tornadic with a rotational intensity clearly stronger than those of non-tornadic supercells.The identified supercells were concentrated within a relatively small area in the northeast quadrant beyond 140 km from the typhoon center.These supercells were found more likely to form over flat topography and were difficult to maintain in mountainous regions.During the study period,more supercells formed offshore than onshore.The mesocyclones of the identified supercells were characterized by a small diameter generally less than 5 km and a shallow depth generally less than 4 km above ground level.An environmental analysis revealed that the northeast quadrant had the most favorable conditions for the genesis of supercell in this typhoon case.The nondimensional supercell composite parameter(SCP)and entraining-SCP(E-SCP)were effective in separating supercell from non-supercell environment.Even though the atmosphere in the typhoon’s northeast quadrant was characterized by an E-SCP/SCP value supportive of supercell organization,orography was an impeditive factor for the supercell development.These findings support the use of traditional parameters obtained from midlatitude supercells to assess the supercell potential in a tropical cyclone envelope.

On the influence of sand-wind on atmospheric environment

The authors seek, through tests on simulated sand samples in a wind tunnel and analysis of minerals combination and trace elements, to discover the environmental implications of flying-up, falling-down and concentration variation as a function of natural wind speed and direction, distance of movement, range and extent of influence on the atmospheric environment, of micro-granular components on the ground surface in the Keerqin desert area in northwest Liaoning Province of China.

Optimization of harmonious development on regional energy－economy－atmospheric environment system

The energy,industrial economy and atmospheric environment were taken into account as a whole cornplex system in this study. Based on the application of grey system theory and the analysis of development coefficients about major parameters of the system,the method of grey developrnent decision was approached, and a new concept-integrated development coefficient was put forward. Furthermore,the reasonable ranking of development decision within eight industrial sectors(building materials,coking,food and drink,chemical engineering,paper rnaking,machinery and electrical appliance,textile, mining)has been concluded from the viewpoint of economic growth, energy saving and ambient air quality protection.

ON THE STUDY OF THE RELATIONSHIPS BETWEEN GUANGZHOU ATMOSPHERIC ENVIRONMENT FACTORS AND THE SARS EPIDEMIC

Based on SARS epidemic data and the corresponding atmospheric data, we used the timescale-partitioning technique, spectrum analysis and correlation analysis to investigate the impacts of the atmospheric environmental factors on the SARS epidemic. Results showed that there were close relations between environmental factors and SARS: The daily probable cases of SARS varied in 3-5 day cycles, much the same as the atmospheric elements did. The variations of the epidemics correlated remarkably with atmospheric elements. So conclusions can be drawn that weather changes have influences on the variations of daily SARS cases. In addition, statistical results showed that cold air activities aggravated the SARS epidemic.

Study on the Characteristics of Atmospheric Environmental Pollution in Jining City

[ Objective] The study aimed to discuss the characteristics of atmospheric environmental pollution in Jining City. Methed] Based on the environmental monitoring data and synchronous meteorological data in 2006 -2010 in Jining City, the distribution regularity of main atmospheric pol- lutants in this city was studied by the method of statistical analysis. [ Result] There were obvious spatial and temporal distribution of atmospheric pollutants in Jining City during 2006 -2010 under the comprehensive effects of meteorological conditions and pollution source emission. That is, at- mospheric pollution was serious in winter but slight in summer, and it was severe in the morning and evening. The load coefficients of SO2, NO2 and PM10 in the atmosphere showed an increasing trend from 2006 to 2010, and their concentrations had close relations with wind direction and ve- locity, urban heat island effect, and motor vehicle quantity. [ Conclusion] This research has important practical significance to the control of atmos- pheric pollution in Jining City.

Study on Atmospheric Environmental Capacity of Shennongjia

Through analysis and evaluation on status quo of atmospheric environment in Shennongjia,atmospheric environment capacity in ClassII functional area of Shennongjia was counted by A value method. The results showed that atmospheric environment capacities of SO2,NO2 and PM10in Shennongjia Forest District were respectively 6 268. 8,17 666. 2 and 2 279. 5 t / a,much larger than emissions of air pollutants in Shennongjia in 2012.

The pH value and electrical conductivity of atmospheric environment from ice cores in the Tianshan Mountains

Electrical Conductivity Measurement （ECM） from ice core is a representative index for atmospheric environmental change. The pH value and ECM from three shallow ice cores （each 3.85 m, 231 ice samples total） on Glacier No.1 at the headwater of Urumqi River, Glacier No.48 in Kuitun area, and Miaoergou Glacier in Hami area in the eastern Tianshan Mountains, western China, were measured and analyzed for atmospheric environment records research. Ice core record shows that the changing trend of pH and ECM in three sites in recent years is different： ECM in Kuitun increases with the ice depth change, but ECM in Hami and Urumqi Glacier No.1 ice cores show a decreasing trend. Average ECM value in Hami is much larger than other two sites, just as the dust concentration and ions concentration are also very high in this site. ECM records in all three sites are mainly affected by aerosol mineral dust of Central Asia, and correlative coefficients of ECM and mineral ions such as Ca^2＋, Mg^2＋, Na^2＋ are all significantly high. The pH value and ECM are also significantly high correlative coefficients in the eastern Tianshan Mountains. Comparison between the eastern Tianshan Mountains and other sites in western China, and Polar Regions, shows that the difference of ECM can very well reflect the spatial difference of worldwide atmospheric environment.

Formulation Method and Management Principle for the Safety Base-line of Atmospheric Environmental Quality

The formulation of the safety base-line for atmospheric environmental quality is not only basic needs of mankind maintaining the quality of survival environment but also concrete measures of red line system for national ecological protection. It is urgent to solve the problem in current environmental management how to draft the safety basa-line of atmospheric environmental quality. To solve this problem, the connotation of safety base-line for atmospheric environmental quality is defined firstly, and then the indexes for atmospheric importance, sensitivity and vulnerability are generalized. Moreover, formulation methods for red, yellow and green lines of the safety base-line for atmospheric environmental quality are put forward ,and corresponding division principle and management principle are put forward finally.

Application Study of Trajectory Plume Model in Atmospheric Environmental Impact Assessment

[ Objective] The research aimed to study application of the trajectory plume model in atmospheric environmental impact assessment. [ Method] Trajectory plume model was used to retrospectively evaluate regional atmospheric improvement degree by fuel gas desulfurization project in Mawan Power Plant of Shenzhen. On this basis, we analyzed applicability of the model in atmospheric prediction of the construction project. [- Re- sult~ Under the situation of complex flow field and variable weather condition, the trajectory plume model displayed good prediction accuracy, to- gether with the use of flow field diagnosis model. Under complex weather condition, this model could be complementary to atmospheric environmen- tal quality prediction model recommended by new atmosphere guidelines, which had the value of popularization in future atmospheric environmental evaluation and planning. [ Conduslon~ Trajectory plume model had broad application potential in atmospheric environmental impact assessment.

Laboratory studies on the infectivity of human respiratory viruses:Experimental conditions,detections,and resistance to the atmospheric environment

The environmental stability of infectious viruses in the laboratory setting is crucial to the transmission potential of human respiratory viruses.Different experimental techniques or conditions used in studies over the past decades have led to diverse understandings and predictions for the stability of viral infectivity in the atmospheric environment.In this paper,we review the current knowledge on the effect of simulated atmospheric conditions on the infectivity of respiratory viruses,mainly focusing on influenza viruses and coronaviruses,including severe acute respiratory syndrome coronavirus 2 and Middle East respiratory syndrome coronavirus.First,we summarize the impact of the experimental conditions on viral stability;these involve the methods of viral aerosol generation,storage during aging and collection,the virus types and strains,the suspension matrixes,the initial inoculum volumes and concentrations,and the drying process.Second,we summarize and discuss the detection methods of viral infectivity and their disadvantages.Finally,we integrate the results from the reviewed studies to obtain an overall understanding of the effects of atmospheric environmental conditions on the decay of infectious viruses,especially aerosolized viruses.Overall,this review highlights the knowledge gaps in predicting the ability of viruses to maintain infectivity during airborne transmission.

Macro Impact of the Law on Prevention and Control of Atmospheric Pollution on Power Industry Development

The newly revised and enlarged main contents of the Law of Prevention and Control of Atmospheric Pollution are described, The macro impacts of the law on the power industry development are analyzed mainly in respects to power demand and readjustment of power structure and layout. clean production and pollution control level, scientific management of environmental protection, in accordance with law as well as changes of construction and operation costs. And finally, several questions worthy to be noted in course of implementation of the new law are enumerated.

Effect of cushion and cover on moisture distribution in clay embankments in southern China

To achieve durability of the embankment in southern China,a method to control the change of moisture content with the cushion and cover was proposed.A finite element model of cushion and cover considering different materials and thicknesses for a typical embankment was built,and 20 numerical analyses of transient seepage in the embankment were simulated.The results show that the sand cushion effectively blocks the effect of groundwater capillary rise and the minimum thickness of the sand cushion is 75 cm without considering the atmospheric environment.With the combination of sand cushion and clay cover,as the thickness of the clay cover increases,the duration time of the moisture content from the initial to relative equilibrium state increases,but the equilibrium moisture content is the same as that of the original embankment.Besides,with the combination of the sand cushion and sand cover,the moisture content inside the embankment remains the same,which is consistent with the optimum moisture content during construction.The combination of 75 cm sand cushion and 30 cm sand cover is a very effective method to block groundwater and atmospheric environment,and achieve the control of the humidity stability of the embankment in southern China.

Biochar Effectively Reduces Ammonia Volatilization From Nitrogen-Applied Soils in Tea and Bamboo Plantations

Intensive practices in forest soils result in dramatic nitrogen(N)losses,particularly ammonia(NH_(3))volatilization,to adjacent environmental areas.A soil column experiment was conducted to evaluate the effect of bamboo biochar on NH_(3) volatilization from tea garden and bamboo forest soils.The results showed that biochar amendment effectively reduced NH_(3) volatilization from tea garden and bamboo forest soil by 79.2%and 75.5%,respectively.The soil pH values increased by 0.53-0.61 units after biochar application.The NH_(4)^(+)-N and total N of both soils were 13.8-29.7%and 34.0-41.9%higher under the biochar treatments than under the control treatment,respectively.In addition,the soil water contents of the two biochar-amended soils were significantly higher(P<0.05),by 10.7-12.5%,than that of the soils without biochar amendment.Therefore,biochar mitigates NH_(3) volatilization from the tested forest soils,which was due to the increases in soil NH_(4)^(+)-N,total N and water contents after biochar amendment.Our main findings suggest that biochar addition is an effective management option for sustainable forest management.

STUDY OF THE VERTICAL WIND FIELD STRUCTURE AND ITS RELATIONSHIP WITH PM2.5 AIR POLLUTION OVER THE PEARL RIVER DELTA IN AUTUMN

Meteorological conditions,particularly the vertical wind field structure,have a direct influence on the PM2.5 concentrations over the Pearl River Delta(PRD).In October 2012,an exceptional air pollution event occurred in the PRD,and a high concentration of PM2.5 was registered at some stations.During days with PM2.5 air pollution,the wind speed was less than 3 m s-1 at the surface,and the vertical wind field featured a weak wind layer(WWL)with a thickness of approximately 1000 m.The mean atmospheric boundary layer height was less than 500 m during pollution days,but it was greater than 1400 m during non-pollution days.A strong negative correlation was detected between the PM2.5 concentration and the ventilation index(VI).The VI was less than 2000 m2 s-1 during PM2.5 air pollution days.Because of the weak wind,sea-land breezes occurred frequently,the recirculation factor(RF)values were small at a height of 800 m during pollution days,and the zones with the lowest RF values always occurred between the heights of 300 and 600 m.The RF values during PM2.5 pollution days were approximately 0.4 to 0.6 below a height of 800 m,reducing the transportation capacity of the wind field to only 40%to 60%.The RF and wind profile characteristics indicated that sealand breezes were highly important in the accumulation of PM2.5 air pollution in the PRD.The sea breezes may transport pollutants back inland and may result in the peak PM2.5 concentrations at night.

Research Progress on PM＿(2.5) Pollution in China

For the status quo that haze weather continuously appeared in every area of China,and air quality sharply declined in recent years,we summarized research progress on PM2. 5in China,introduced the concept of PM2. 5,pointed out the adverse effects of PM2. 5on atmospheric environment and human health,and simply summarized monitoring method of PM2. 5. At present,China＇s researches about PM2. 5mainly concentrated in the impact on atmospheric environment,comparative analysis between PM2. 5and PM10,and analysis on various components of PM2. 5. Finally,we put forward some suggestions strengthening technique research and improving atmospheric environment in China.

Development of an Accurate Urban Modeling System Using CAD/GIS Data for Atmosphere Environmental Simulation

This paper presents an urban modeling system using CAD/GIS data for atmosphere environmental simulation, such as wind flow and contaminant spread in urban area. The CAD data is used for the shape modeling for the high-storied buildings and civil structures with complicated shape since the data for that is not included in the 3D-GIS data accurately. The unstructured mesh based on the tetrahedron element is employed in order to express the urban structures with complicated shape accurately. It is difficult to understand the quality of shape model and mesh by the conventional visualization technique. In this paper, the stereoscopic visualization using virtual reality (VR) technology is employed for the verification of the quality of shape model and mesh. The present system is applied to the atmosphere environmental simulation in urban area and is shown to be an useful planning and design tool to investigate the atmosphere environmental problem.

Performance Degradation of the Repeated Recycled Aggregate Concrete with 70% Replacement of Three-generation Recycled Coarse Aggregate

The feasibility of using different generations recycled coarse aggregate（RCA） on structural concrete was fully evaluated by studying the performance of the recycled coarse aggregates and their corresponding concretes, the different generations of RCA were recycled by following the repeated mode of ‘concrete-waste concrete-coarse aggregate-concrete＇. Moreover, the focus was on ‘three generations＇ of repeated RCAs, the RCA was produced by crushing and regenerating the artificial accelerated degraded concrete, the process was designed to follow the nature degradation of the concrete with a coupling action of accelerated carbonation and bending load. The properties of x-generation（x=1, 2 or 3） of repeated RCA were systematically investigated and the compressive and splitting tensile strengths of relating structural concretes（with 70% replacement of x-generation of RCA） were studied accordingly. The results show a competent compressive and splitting tensile strength of 30 MPa at 28 th day of structural concretes with all generations of repeated RAC. And the gradual degraded performance of the repeated RCAs was observed with an increased numbers of repetition（1〉2〉3 generations）, the overall performances of all repeated RCAs fulfill the Class Ⅲ according to Chinese Standards GB25177-2010. Our gained insight demonstrates a feasibility of using at least 3 generations of repeated RCA for the production of normal structural concrete.