Particle Size Estimation Based on Edge Density

Given image sequences of closely packed particles, the underlying aim is to estimate diameters without explicit segmentation. In a way, this is similar to the task of counting objects without directly counting them. Such calculations may, for example, be useful）Cast estimation of particle size in different application areas. The topic is that of estimating average size （=average diameter） of packed particles, from formulas involving edge density, and the edges from moment-based thresholding are used. An average shape factor is involved in the calculations, obtained for some frames from crude partial segmentation. Measurement results from about 80frames have been analyzed.

Experimental Investigation of Lower Hybrid Wave Coupling in HT-7

Experiments on lower hybrid wave （LHW） coupling were investigated in the HT- 7 tokamak. Good coupling of LHW plasma has been demonstrated at different conditions in the HT-7 tokamak. Relevant results have proved that LHW-plasma coupling is affected by the phase difference between adjacent waveguides. Furthermore, the edge density around the grill and relevant coupling can be adjusted by changing the plasma line average density or the gap value between the LH grill and the last closed flux surfaces （LCFS）. It is found that the coupling of LHWs becomes poor when the edge density around the LH grill is large enough in the HT-7 tokamak, and that coupling remains good with a proper edge density. With increasing LHW power, it is also found that the reflection coefficients （RCs） increase due to non-linear effects under conditions of low edge recycling, but can decrease under high edge recycling. The edge density depends mainly on the competition between the ponderomotive force （PMF） and the edge recycling intensity in the HT-7 tokamak.

Do green spaces affect the spatiotemporal changes of PM_(2.5) in Nanjing?

Introduction:Among the most dangerous pollutants is PM_(2.5),which can directly pass through human lungs and move into the blood system.The use of nature-based solutions,such as increased vegetation cover in an urban landscape,is one of the possible solutions for reducing PM_(2.5) concentration.Our study objective was to understand the importance of green spaces in pollution reduction.Methods:Daily PM_(2.5) concentrations were manually collected at nine monitoring stations in Nanjing over a 534-day period from the air quality report of the China National Environmental Monitoring Center(CNEMC)to quantify the spatiotemporal change of PM_(2.5) concentration and its empirical relationship with vegetation and landscape structure in Nanjing.Results:The daily average,minimum,and maximum PM_(2.5) concentrations from the nine stations were 74.0,14.2,and 332.0μg m^(−3),respectively.Out of the 534 days,the days recorded as“excellent”and“good”conditions were found mostly in the spring(30.7%),autumn(25.6%),and summer(24.5%),with only 19.2% of the days in the winter.High PM_(2.5) concentrations exceeding the safe standards of the CNEMC were recorded predominately during the winter(39.3-100.0%).Our hypothesis that green vegetation had the potential to reduce PM_(2.5) concentration was accepted at specific seasons and scales.The PM_(2.5) concentration appeared very highly correlated(R2>0.85)with green cover in spring at 1-2 km scales,highly correlated(R2>0.6)in autumn and winter at 4 km scale,and moderately correlated in summer(R2>0.4)at 2-,5-,and 6-km scales.However,a non-significant correlation between green cover and PM_(2.5) concentration was found when its level was>75μg m^(−3).Across the Nanjing urban landscape,the east and southwest parts had high pollution levels.Conclusions:Although the empirical models seemed significant for spring only,one should not devalue the importance of green vegetation in other seasons because the regulations are often complicated by vegetation,meteorological conditions,and human activities.

Effects of landscape heterogeneity and breeding habitat diversity on rice frog abundance and body condition in agricultural landscapes of Yangtze River Delta,China

Amphibia ns play a key role in structuring biological assemblages of agricultural landscapes,but they are threatened by global agricultural intensification.Landscape structure is an important variable in flue ncing biodiversity in agricultural la ndscapes.However,in the Yangtze River Delta,where a"farmland-orchard-fishpond"agricultural pattern is common,the effects of landscape construction on anuran populations are unclear.In this study,we examined the effects of agricultural landscape parameters on the abundance and body condition of the rice frog(Fejervarya multistriata),which is a dominant anuran species in farmland in China.Employing a visual encounter method,we surveyed rice frog abundance for 3years across 20 agricultural landscapes.We also calculated the body condition index(BCD of 188 male frog individuals from these agricultural landscapes.Landscape variables,comprising landscape compositional heterogeneity(using the Shannon diversity in dex of all land cover types except buildings and roads),Ian dscape con figurational heterogeneity(using landscape edge density),breeding habitat diversity(using the number of 5 waterbody types available as breeding habitats),and areas of forest were also measured for each 1-km radius landscape.We found that the amount of forest in each agricultural Iandscape had a sign讦icant positive relationship with rice frog abundance,and breeding habitat diversity was positively related to the BCI of male rice frogs.However,body condition was negatively impacted by landscape configurational heterogeneity.Our results suggested the importance of nonagricultural habitats in agricultural landscapes,such as waterbodies and forest,to benefit rice frog population persistenee.