In seasonal frozen regions,shallow landslide hazards in soil slopes usually happen.The failure surface is always in the freezing and thawing surface of the soil slope because the direct factor of soil slope failure is the shear strength of the soil between the freezing and thawing surfaces,which is determined by the two parameters of Cohesioncand Friction angleφ.In this research a simulation experiment of freeze-thaw soil interface with different aggregate materials is designed by alternating the freeze-thaw cycle times and the water content of soil,then the c and theφare obtained.Finally the deterioration model of the two shear strength parameters is put forward.The results show that the parameter of shear strength will be deteriorated due to the two above influential factors.
Photocatalytic H 2 O 2 production is significantly accelerated in microdroplets, benefiting from O 2 availability improvement, interfacial electric field, and reaction energy decrease.
Abstract Carbonate radical anion () is generally overlooked in atmospheric chemistry. Our recent work emphasizes the important role of carbonate radicals produced on mineral dust surfaces in fast sulfate production under solar irradiation in the presence of CO 2 at specifically low RH and light intensity. Yet so far how involves and affects secondary sulfate production under diverse RH, light intensity, and complex constituent matrix remains unknown, which essentially limits our comprehensive knowledge of initiated SO 2 oxidation scheme in the atmosphere. Herein, we explored the heterogeneous SO 2 oxidation over both model and authentic dust and clays in the presence of CO 2 at atmospheric relevant RHs and light intensities. Interestingly, we observe that CO 2 promotes sulfate yield over authentic dust and clays at atmospheric‐relevant RH and light intensity. This observation relates to the favorable kinetic between SO 2 oxidation and while auto‐quenching of these radical ions is largely minimized due to the sufficient sites of crustal constituents. Furthermore, employing a suite of authentic dust and machine learning strategies, we evaluated the relative importance of each constituent within airborne minerals or clays as well as environmental conditions including relative humidity, light intensity, and CO 2 concentration in affecting SO 2 uptake capability. On this basis, sulfate formation mediated by dust‐driven pathway, accounting for nearly ∼20.9% of overall contribution by the end of this century during some pollution episodes, even higher than gas‐phase (∼16.9%), will be increased by 163% if CO 2 ‐initiated SO 2 oxidation scheme is incorporated.
Heterogeneous SO 2 conversion over FeOOH minerals leads to the considerable formation of atmospheric sulfate aerosols, influenced by crystal structure, light irradiance and oxalate coating.
The multiphase oxidation of sulfur dioxide (SO2) to form sulfate is a complex and important process in the atmosphere. While the conventional photosensitized reaction mainly explored in the bulk medium is reported to be one of the drivers to trigger atmospheric sulfate production, how this scheme functionalizes at the air–water interface (AWI) of aerosol remains an open question. Herein, employing an advanced size-controllable microdroplet-printing device, surface-enhanced Raman scattering (SERS) analysis, nanosecond transient adsorption spectrometer, and molecular level theoretical calculations, we revealed the previously overlooked interfacial role in photosensitized oxidation of SO2 in humic-like substance (HULIS) aerosol, where a 3–4 orders of magnitude increase in sulfate formation rate was speculated in cloud and aerosol relevant-sized particles relative to the conventional bulk-phase medium. The rapid formation of a battery of reactive oxygen species (ROS) comes from the accelerated electron transfer process at the AWI, where the excited triplet state of HULIS (3HULIS*) of the incomplete solvent cage can readily capture electrons from HSO3– in a way that is more efficient than that in the bulk medium fully blocked by water molecules. This phenomenon could be explained by the significantly reduced desolvation energy barrier required for reagents residing in the AWI region with an open solvent shell.
Chemodynamic therapy as an emerging therapeutic strategy has been implemented for oncotherapy. However, the reactive oxygen species can be counteracted by the exorbitant glutathione (GSH) produced by the tumor cells before exerting the antitumor effect. Herein, borneol (NB) serving as a monoterpenoid sensitizer, and copper sulfide (CuS NPs) as an NIR-II photothermal agent were loaded in a thermo-responsive vehicle (NB/CuS@PCM NPs). Under 1,060-nm laser irradiation, the hyperthermia produced by CuS NPs can be used for photothermal therapy and melt the phase change material for drug delivery. In the acidity microenvironment, the CuS NPs released from NB/CuS@PCM NPs could degrade to Cu 2+ , then Cu 2+ was reduced to Cu + during the depletion of GSH. As Fenton-like catalyst, the copper ion could convert hydrogen peroxide into hydroxyl radicals for chemodynamic therapy. Moreover, the NB originated from NB/CuS@PCM NPs could increase the intracellular ROS content to improve the treatment outcome of chemodynamic therapy. The animal experimental results indicated that the NB/CuS@PCM NPs could accumulate at the tumor site and exhibit an excellent antitumor effect. This work confirmed that the combination of oxidative stress–induced damage and photothermal therapy is a potential therapeutic strategy for cancer treatment.
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)