The rapid development of the tourism industry has been accompanied by an increase in CO₂ emissions and has a certain degree of impact on climate change. This study adopted the bottom-up approach to estimate the spatiotemporal change of CO₂ emissions of the tourism industry in China and its 31 provinces over the period 2000–2015. In addition, the decoupling index was applied to analyze the decoupling effects between tourism-related CO₂ emissions and tourism economy from 2000 to 2015. The results showed that the total CO₂ emissions of the tourism industry rose from 37.95 Mt in 2000 to 100.98 Mt in 2015 with an average annual growth rate of 7.1%. The highest CO₂ emissions from the tourism industry occurred in eastern coastal China, whereas the least CO₂ emissions were in the west of China. Additionally, the decoupling of CO₂ emissions from economic growth in China’s tourism industry had mainly gone through the alternations of negative decoupling and weak decoupling. The decoupling states in most of the Chinese provinces were desirable during the study period. This study may serve as a scientific reference regarding decision-making in the sustainable development of the tourism industry in China.

The calculation of tourism carbon footprint is of great significance to low-carbon tourism. This study estimates the tourism carbon footprint in Heilongjiang Province from 2009 to 2018 by using tourism carbon footprint and tourism carbon capacity models. The results show that the total tourism carbon footprint of Heilongjiang Province increased fast to 2.97 times from 5.926million tons in 2009 to 21.13million tons in 2018, while its per capita tourism carbon footprint increased from 53.9 kg to 116.0 kg. During the same period, tourism carbon capacity continued to grow steadily from 15.18billion tons to 21.96billion tons, and the growth rate was 50% of the growth rate of tourism carbon footprint. Tourism carbon emissions can be absorbed by environmental capacity, and the risk of carbon deficit is relatively small.

Organic dye molecules of styryl 7 were introduced into the channels of ${\mathrm{AlPO}}_4\text{-5}$ single crystals. Polarized absorption and photoluminescence spectra of the dye molecules were investigated. The polarization angle dependence of the absorption and photoluminescence intensity indicates that the dye molecules are highly oriented in the channels. The hexagonal-shaped ${\mathrm{AlPO}}_4\text{-5}$ single crystal serves as a natural microcavity for lasing action of the dye molecules. The microcavity modes of the lasing action were also demonstrated.

This study analyses the composition and evolution of carbon dioxide emissions from the tourism industry in Heilongjiang Province and its 12 regions by the tourism consumption stripping coefficient method and calculates the decoupling relationship between the carbon dioxide emissions and economic growth of tourism from 2010 to 2019. The empirical results are as follows. (1) From 2010 to 2019, carbon dioxide emissions from Heilongjiang Province’s tourism industry and its subsector increased steadily, of which the tourism industry accounted for a relatively large amount of carbon dioxide emissions in “Transport, Storage, and Post.” (2) Time series analysis reveals that the carbon dioxide emissions of tourism basically show an increasing trend and there are still multiple decoupling relationships with economic growth. Expansive decoupling and weak decoupling have occurred more frequently. (3) Spatial analysis reveals that the carbon dioxide emissions of the regional tourism industry show a fluctuating upward trend. The tourism industry in Harbin has significantly higher carbon dioxide emissions than in other regions. In addition, this study provides feasible suggestions and countermeasures for low-carbon tourism development in Heilongjiang Province. The findings are considered useful in future planning of energy conservation and emission reduction in Heilongjiang Province and the regional tourism industry.

The thermal adsorption/desorption process of selenium species in the channels of AlPO4-5 (AFI) single crystals is studied by simultaneous thermogravimetry (TG) and differential scanning calorimetry (DSC). There exist two peaks in the TG and DSC curves, indicating that two different structures of Se species, helical chain and 8-member ring, coexist in the AFI channels. Polarized Raman and optical absorption spectra show that the helical chains are highly aligned along the channel direction, while the Se8 rings are randomly oriented in the channels. The helical chains have a lowest optical absorption band at 2.6 eV, which is strongly polarization dependent, while the 8-member rings have a lowest absorption band at 3.0 eV that varies slowly with the light polarization.