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This study was conducted to provide reference for plant landscaping, optimization of planting structure and rational allocation of species in Cedrus deodcua gardens. [Methods] With three common garden plants in northern China, Trifolium repens L, Poa pralensis L and Trifolium pralense L, as receptors, the effects of four concentrations ( 0.025, 0. 05, 0.075 and 0.10 g/ml) of C. deodara needle extract on seed germination and early seedling growth of the three turf grasses were studied by the Petri dish filter paper method, using a clear water treatment ( 0 g/ml) as control check (CK). Data were subjected to analysis of variance ( ANOVA) and multiple comparisons (Duncan) using SPSS16. 0. [Results] Different concentrations of C. deodcua needle extract had significant inhibitory effects on seed germination, radicle and seedling height growth of T. repens, T. pratense and P. pratensis ( P < 0.05 ), and the inhibitory effects increased with the increase of concentration. When the concentration reached 0. 075 g/ ml, seed germination and seedling growth of T. repens stopped, and radicle and seedling growth of T. pratense and P. pralensis also stopped. When the concentration was equal to 0.10 g/ ml, germination of T. pralense and P. pralensis seeds was inhibited, and the absolute values of allelopathic index was the largest, that is, the inhibitory effects were the largest. And with the increase of concentration, the absolute value of synthetical allelopathic index also increased. The extract of C. deodcua needles contained main allelochemicals leading to the scarcity of understory vegetation. [Conclusions] This study provides a theoretical basis for reasonable garden plant configuration during C. deodara greening and garden landscaping. [ABSTRACT FROM AUTHOR]

Strengthening environmental regulation (Reg) is an important measure to solve energy and environmental problems, then to realize the profit sustainable growth (Gro). Taking 116 listed renewable energy enterprises in China from 2010 to 2019 as samples, this paper uses FE and SYS-GMM models to examine the moderating effect of three types of Reg in the relationship of factor market distortions (Dist) and the Gro. The conclusions are as follows: For the direct impact, capital and labor market distortions (DistK and DistL) hinder the Gro. Specifically, the absolute value of the coefficient of DistK in state-owned enterprises (SOEs) is greater than that of the DistL, which indicates that the inhibitory effect of DistK in SOEs is more significant. For the indirect impact, the coefficients of economic and supervised environmental regulation (RegE and RegS) are positive and significant, and promote the Gro of SOEs and non-SOEs, while legal environmental regulation (RegL) is the opposite, which shows that Reg has significant "cost effect" and "rebound effect". Moreover, Reg has a positive moderating effect, which is mainly reflected in SOEs, and alleviates the inhibitory effect of DistK and DistL on Gro to a certain extent. Finally, this paper puts forward some targeted policy suggestions. [ABSTRACT FROM AUTHOR]

Long-term erosion and repeated scouring of water significantly affect the technical properties of coals, which are the essential elements that must be considered in evaluating an underground reservoir coal column dam's standing sustainability. In the paper, the coal pillar dam body of the 22 layers of coal in the Shangwan Coal Mine is studied (22 represents No. 2 coal seam), and the water content of this coal pillar dam body is simplified into two types of different water content and dry–wet cycle. Through acoustic emission detection technology and energy dissipation analysis method, the internal failure mechanism of coal water action is analyzed. This study revealed three findings. (1) The crest pressure, strain, and resilient modulus in the coal sample were inversely related to the water content along with the dry–wet cycle number, while the drying–wetting cycle process had a certain time effect on the failure to the sample. (2) As the moisture content and the dry–wet cycle times incremented, three features were shown: first, the breakage pattern is the mainly stretching fracture for the coal specimen; second, the number and absolute value of acoustic emission count peaks decrease; third, the RA-AF probability density plot (RA is the ratio of AE Risetime and Amplitude, and AF is the ratio of AE Count and Duration) corresponds more closely to the large-scale destruction characteristics for the coal samples. (3) A higher quantity of wet and dry cycles results in a smoother energy dissipation curve in the compacted and flexible phases of the crack, indicating that this energy is released earlier. The research results can be applied to the long-term sustainability assessment of the dams of coal columns for underground reservoirs and can also serve as valuable content to the excogitation of water-bearing coal column dams under similar engineering conditions. [ABSTRACT FROM AUTHOR]

The current standard in China does not specify the standard test method for determining Poisson's ratio, and the Poisson's ratio used in pavement design is often roughly fixed, which can result in large errors in the calculations and analysis of road structure. In this paper, the research on different test methods for Poisson's ratio is carried out and the non-linear characteristics of tensile and compressive Poisson's ratio on pavement materials under different influencing factors are analyzed. The results indicate that the absolute value of the ratio between transverse rebound strain and longitudinal rebound strain under 50% of the maximum destructive load can objectively characterize the mechanical properties of Poisson's ratio, and it is the optimal measurement method for Poisson's ratio in asphalt pavement materials. The Poisson's ratio of two pavement materials both decreases with the increase of loading rate and gradually tends to a constant value. Cement dosage and temperature are the most significant factors affecting the tensile and compressive Poisson's ratio of cement stabilized crushed stone and asphalt mixture, respectively. Specifically, when cement dosage increases by 1%, the Poisson's ratio of cement stabilized crushed stone decreases by approximately 10%, and the temperature has a significant influence on the difference in tension and compression for Poisson's ratio of asphalt mixture (up to 40%). The asphalt content corresponding to the minimum Poisson's ratio is basically consistent with the optimal asphalt content obtained by the Marshall volume method. Based on these, a quantification value-taking model is established of the tensile and compressive Poisson's ratios of typical asphalt pavement materials varying with multiple factors. The research results can serve as a reference for the scientific value-taking of pavement structural design parameters considering the different mechanical characteristics of materials in tension and compression. • The scientific and reasonable measuring method of Poisson's ratio was established. • The quantitative model of Poisson's ratio affected by many factors was established. • The Poisson's ratio increases with loading speed and gradually tends to stabilize. • The optimum asphalt content mixture by Marshall method has minimum Poisson's ratio [ABSTRACT FROM AUTHOR]

[Display omitted] • The land surface area of the mainland China was calculated based on 30 m resolution DEM. • Absolute difference and relative difference of ESV based on surface area and plane area was conducted at country, provincial and county levels. • The characteristics of temporal-spatial variation of ESV of various ecosystems based on surface area in China were revealed. • The total ESV based on surface area was compared with other studies. • The importance of the surface area in land resource survey, natural asset estimation and ecological protection was emphasized. The assessment of ecological assets is of great significance for protecting and using ecological resources. Traditional methods of ecological assets assessment, which adopt the planar area as the standard, often ignore the impact of the surface area, resulting in a large difference between the evaluation and the actual result. To fill this gap, this paper conducted research on ecological assets assessment based on surface area. Taking mainland China into consideration, this paper constructed a triangulation network based on 30 m resolution DEM data to simulate the real land surface form and calculate its surface area. Then, land use/cover data from 1995, 2000, 2005, 2010, and 2015 were used to estimate the ecosystem service value (ESV) and analyze its spatial variation. This paper found that: (1) The surface area of mainland China is 1.04 × 107 km2, which is 8.2 × 105 km2 larger than the planar area; (2) A huge difference was found between the total ESV based on the surface and planar area, with an absolute difference of ∼$141.66-$144.14 billion and a relative difference of ∼ 10%. For different ecosystem types, the largest difference was found in the forest ecosystem, followed by the grassland ecosystem, while the wetland ecosystem showed the smallest difference; (3) The high value of absolute difference between the ESV based on the surface and planar area was concentrated in Tibet and Northeast China. The high value of relative difference was mainly distributed in Central and Southern China. On the provincial level, the absolute difference in Tibet ranked in the first place. There was a total of 14 provinces showing a relative difference above 10%; (4) The total ESV based on surface area was basically unchanged, while various ecosystems underwent significant changes. The ESV of wetland increased by nearly 50%, while the ESV of grassland decreased by more than 10%; and (5) Change in the ESV based on surface area showed obvious spatial heterogeneity. High-High cluster was located in Tibet and the Northeast China while the Low-Low cluster was distributed in the North China Plain and Xinjiang. This paper emphasized the importance of the surface area in resource survey and asset estimation and gave more effective suggestions for ecological protection. [ABSTRACT FROM AUTHOR]

The latest gravity survey of the gravity base network in Qinghai Province, China, was conducted with six Scintrex CG gravimeters and this gravity survey was tied to existed gravity reference stations. In this gravity network with long segments and very rugged topography, the calibration of scale factors is a time-consuming progress and its accuracy may be affected by many uncertainties, and the change in drift rates of the relative gravimeters are complex over time in this long-term survey. The reasonable calculation of scale factors and drift rates plays an important role in improving the gravity estimation accuracy. In this paper, based on the least squares, robust least squares, and Bayesian methods, various parameter calculation methods were employed to process this gravity network. The performance and practicality of each method were analyzed in terms of internal and external accuracy. The results indicated that the scale factors calibrated in the baseline field had poor applicability due to insufficient gravity difference, in this case, the scale factors estimated by the adjustment models were more accurate, which weakened the correlation between gravity differences and mutual differences. The drift rates estimated by the Bayesian method were relatively smooth over time, while drift rates estimated using symmetric observations were more practical for the gravimeter with highly variable drift. The weight constraints of observations can be optimized by the robust least squares method, the gravity values obtained by it were more consistent with absolute gravity values than those obtained by the least squares method, and the robust least squares method was recommended to process gravity data in plateau areas. [ABSTRACT FROM AUTHOR]