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Based on the building of a kindergarten in Weinan, Shaanxi Province, this paper explores the influence of different envelope structures and heating modes on the indoor thermal environment for the energy saving and thermal comfort of the existing buildings. Using operating temperature as the evaluation index of thermal comfort, the 15 designed schemes were simulated through Energyplus software and actual measurement to obtain the operating temperature change law and annual heating energy consumption value. The envelope structure optimized by choosing energy-saving building materials such as expansion perlite and foam cement is obviously conducive to the improvement of indoor thermal comfort, and the thickness of the insulation layer increases, and the operating temperature increases accordingly; Although the standard effective temperature in intermittent heating mode is slightly lower than that in continuous heating mode, the standard effective temperature rises significantly with the extension of preheating time, which can meet the requirements of thermal comfort.After energy saving transformation, the total heating energy consumption of the kindergarten building is reduced by up to 3644 GJ, and the energy-saving rate reaches 67%.

Clogging is a common and difficult problem in subsurface flow wetlands. In this study, 2-4mm, 4-8mm, 8-10mm lightweight ceramsite were used as suspended media beds and 5-10mm gravel was used as traditional substrate bed as control. The effects of these four substrate beds on the purification of water quality and the change of flow capacity in the clogging process in the non-deformable inorganic particle wastewater, deformable inorganic particle wastewater and organic particle wastewater were studied. After the beds were clogged, using the characteristics of lightweight ceramsite floating up and down with water level, the mitigation effect of clogging with water level fluctuation at different heights (10 cm, 20 cm, 30 cm, 40 cm) was explored. The results showed that four kinds of beds had effect on the removal of turbidity and suspended particles. The beds in the treatment of non-deformable inorganic particle wastewater were more likely to cause wetland gap clogging; In the absence of plants, compared with inorganic particles, the clogging degree of substrate in the treatment of organic suspended particulate wastewater was not obvious. After clogging, lightweight ceramsite floats up and down with the water level, three kinds of wetland clogging have been alleviated to some extent.

Nonsymmorphic symmetries play a significant role in the emergence of topological nontrivial phases in some 2D materials. Herein, a new 2D material P21/m‐MoTe2 with nontrivial topological properties and nonsymmorphic symmetries is proposed. With the help of first‐principles calculations, it is found that it is dynamically stable, and has relatively high energetic stability. When spin–orbit coupling (SOC) is ignored, this material is a semimetal with two intersects appearing on the high‐symmetry line Γ–Y. Detailed symmetry analysis reveal that they are protected by the screw operator C˜2y. After SOC is turned on, it turns into a topological insulator with a global bandgap of 94 meV. The large gap ensures that the topological nontrivial phase is robust to an external perturbation. The discovery of nonsymmorphic P21/m‐MoTe2 expands the family of transition metal dichalcogenides and provides a new platform to study topological phases in 2D nonsymmorphic materials. [ABSTRACT FROM AUTHOR]