The distribution and spatial variability of soil aggregates and their organic carbon and their responses to environmental factors in Daxing'anling forest region were studied by field investigation and laboratory analysis. In Daxing'anling forest region, 75 sampling points were set up based on kilometer grid, and the sample circle with radius of 17.85m was set at each sampling point. In each circle, three samples of 0-20 cm topsoil were taken to determine soil chemical indexes, soil aggregates and their organic carbon content. The results showed that: (1) the soil aggregate content followed the order as (0.25~2 mm aggregate) > (<0.053 mm aggregate) > (0.053~0.25 mm aggregate). The spatial autocorrelation of each fraction of aggregate were moderate, and they were affected by the structural factors such as climate, vegetation, soil and random factors such as human activities. The content of 0.25~2 mm and <0.053 mm aggregates decreased gradually from north to south, while the content of 0.053~0.25 mm aggregates was opposite to them. (2) The organic carbon content of soil aggregates was mainly concentrated in the 0.25~2 mm large aggregates (19.84 g/kg) with the contribution rate 50.39%; the organic carbon contents of each fraction of aggregate showed high spatial autocorrelation which was mainly affected by structural factors; the spatial difference of soil aggregate content in each particle size was not significant, and the distribution was patchy. There was no significant spatial difference in the organic carbon contents of soil aggregate in different fractions with patch distribution characteristics. (3) Temperature had no significant effect on the formation and stability of soil aggregates, and precipitation is beneficial to the formation of micro-aggregates <0.053 mm; soil organic carbon was conducive to the cementation of small-sized aggregates into large aggregates, which had a positive effect on the stability of soil aggregates. There was a significant positive correlation between SOC and organic carbon of soil aggregates in different fractions, and the correlation degree was gradually weakened with the decrease of particle size; the contents of soil nitrogen, phosphorus, potassium and other nutrients could promote the organic carbon accumulation in soil aggregates. The results can provide the basis for the soil rational use and the carbon fixation capacity improvement of forest in Daxing'anling forest region.

The rapid development of the construction industry since the 21st century has intensified the contradiction between the use of environmental resources and economic development, and sustainable development is facing severe challenges. In order to coordinate the development of the construction industry’s resource consumption and the eco-economic system, this article uses the emergy analysis method and combines the original data of the construction industry in Xining City from 2011 to 2017 to build a comprehensive analysis of the construction industry system in Xining by constructing an emergy index system. The results show that Xining’s construction industry is more and more dependent on various external energy inputs, and the proportion of local environmental resources it is relying on is getting smaller and smaller, indicating that Xining’s construction industry is more open to the outside world and the more economic development and the quality of life of the people Come the better.

(1) Background: The preservation of soil organic carbon (SOC) by soil aggregates (SA) is a key mechanism for the stability of the soil carbon (C) pool. (2) Methods: Soil samples were collected at a 0–20 cm depth from 75 sites across the forest regions of the Greater Khingan Mountains, China, and were fractionated as SA of 0.25–2 mm, 0.053–0.25 mm, and <0.053 mm by a wet-sieving method. The spatial patterns of SA and associated organic C (OC) were investigated, as well as their associations with environmental factors. (3) Results: The predominant SA was the SA fraction (SAF) of 0.25–2 mm. The spatial pattern of SA, with moderate spatial autocorrelation, was found to be associated with aggregate size. SOC was mainly accumulated in the 0.25–2 mm SAF, accounting for 50.39% of the total content of aggregate SOC; the total SOC content in all SAF showed strong spatial autocorrelations without significant differences. No significant correlations were found between temperature and SA variables. Precipitation presented significantly positive and negative correlations with the SAF of <0.053 mm and 0.053–0.25 mm, respectively. SOC was favorably associated with macroaggregate, geometric mean diameter (GMD), and mean weight diameter (MWD); however, the correlation between SOC and aggregate SOC lessened as particle size decreased. The aggregate SOC contents were significantly linked with NH4+-N, AK, and TP, while 0.25–2 mm SA content was negatively related with pH. (4) Conclusions: Precipitation was helpful for the development of clay aggregates (<0.053 mm), i.e., increasing rainfall-induced aggregate disruption. SOC encourages small SA cementing to large SA, which improves SA stability. OC associated with the SAF of 0.25–2 mm and 0.053–0.25 mm was positively correlated with soil nutrients such as nitrogen, phosphorus, and potassium, suggesting that the formation of aggregates was conducive to the preservation of soil nutrients.

Analyzing the literature in the field of prefabricated building and BIM integration is helpful to promote the development of prefabricated building informatization. Using the Web of Science core collection database as the data source, this study screened relevant literatures at home and abroad from 2000 to 2020. CiteSpace and VOSviewer were used to conduct visual analysis on the characteristics of published articles, research hotspots and evolution trends based on bibliometrics. The results show that the related literature heat in this field will continue to increase in China in the future. Design and management have become the focus and trend of current scholars in this field. Exploring all kinds of development obstacles has become a new research hotspot in the past two years.