Exploring response of ecosystem servicing values on land use changes provides references in optimizing human-land relation and promoting regional sustainable development. This paper, based on Sichuan's 2000 to 2020 land use data, studies its land use changes, uses ecosystem servicing valuation and gray correlation method to explore the response of regional ecosystem servicing values on land use changes. In Sichuan province, land categories vary in quantities, structural changes and dynamic changes. Ecosystem servicing values in proportion provided by land categories ranks show a decreasing order, woods land, grass land, waters, farmland, unused land and construction land. Woods land, grass land and farmland are major factors contributing to ecosystem servicing values, while waters, construction land and unused land are minor factors. In order to promote a sustainable land use and regional sustainability, appropriate land use planning and policies play a key role. This paper presents suggestion on maintaining a sound growth of ecosystem for different land categories.

This paper, aiming at the relation between fixed asset investment and carbon emission in oil-gas sector, uses China's 2002 to 2021 oil-gas sector panel data to establish a fixed effect model for exploring the impacts of fixed asset investment on carbon emission, and employs mediating effect model and stepwise regression to study the relation among fixed asset investment, R&D investment per capita and carbon emission in oil-gas sector and the impacting mechanism. Fixed asset investment in oil-gas sector has largely decreased carbon emission ratio with an impact coefficient at -1.913, which means increasing fixed asset investment in oil-gas sector can outstandingly decrease carbon dioxide emission. Regression on replacing explained variables/explaining variables and adding controlling variables confirms the above results. R&D investment per capita plays a mediating role between fixed asset investment and carbon emission ratio with a mediating value at 24.7%, fixed asset investment in the oil-gas sector significantly reduced R&D investment per capita, while R&D investment per capita can effectively limit carbon emission ratio via green technical innovation. The impact of fixed asset investment on carbon emissions in the oil-gas sector is short-term and the impact coefficient is small, while the impact on main business income is long-term and the impact coefficient is large. During stably growing and transforming periods in China's oil-gas sector, fixed asset investment difference impacts carbon emission ratio, heterogeneity test showing that there is no obvious correlation between fixed asset investment and carbon emission ratio during the stably growing period, and that fixed asset investment can largely limit carbon emission ratio during transforming/upgrading period in oil-gas sector.

Based on the observation and study of the samples of 3^#  and 15^#  coal seams in ten coal mines in the south of Qinshui Basin with optical microscope and scan electron microscope, the authors expound the characteristics of coal microfracture and its correlations with coal maceral composition. The study shows that the fractures are commonly present in both 3^# and 15^# coal seams. They are more developed in 15^# coal seam than in 3^# coal seam, but some fractures in 15^#  coal seam are filled. Fractures, including endogenic fracture and exogenous fracture, are mostly developed in vitrinite, among which telocollinite is primary and desmocollinite the second. In inertinite, fractures are primarily developed in fusinite and are mainly of tensional fractures. Endogenic fractures are not developed in inertinite of high rank coal. The fracture is controlled by coal maceral composition in the procedure of coalification through the release of water adopted in paludification, the combined action of composition structure and generated gas, and mechanical behaviors.

Coal mines in Northern China are becoming exhausted in the shallow after a long period of mining, so it is a necessity to look for coal in the deep. This paper summarizes systematically the distribution of coal resources and deep potential in five provinces in the east of northern China, analyzes the change trend of coal beds in the deep, and predicts the prospecting in the existing coal mines. The deep coal resources (-800~-1500m) are of huge potential, 2~4 times the shallow (above-800m) in Hebei, Shandong, Jiangsu and Anhui. Gas coal fields are generally located in the shallow while coking coal fields are in the deep. The future prospecting lies in the deep and outskirts of existing mines, Coal beds under the large thrusts and complicated structures are of economic values. A detailed geological exploration and development planning must be completed due to a complicated geology in the deep, giving priority in developing those of stable and quality coal beds by  verifying the deep structures in order to avoid severe geological disasters.

The global economic downturn trigged by international financial crisis has exerted an impact on the online tourism industry. This industry is now developing slowly. The new vertical search websites, travel agencies, hotels and airlines hamper the development of online tourism industry through direct selling. This paper, based on Industrial Value Chain theory and Porter’s Competition theory of five forces, analyzes the internal and external environments of online tourism industry, evaluates the environmental factors influencing online tourism with a matrix method.