Exploring HONO formation and its role in driving secondary pollutants formation during winter in the North China Plain.

Daytime HONO photolysis is an important source of atmospheric hydroxyl radicals (OH). Knowledge of HONO formation chemistry under typical haze conditions, however, is still limited. In the Multiphase chemistry experiment in Fogs and Aerosols in the North China Plain in 2018, we investigated the wintertime HONO formation and its atmospheric implications at a rural site Gucheng.

A dynamic perspective on the evolution of perceived stress levels in Switzerland: drivers before and during the COVID-19 pandemic.

As a major socio-historical event affecting different aspects of life, the COVID-19 pandemic presents a unique opportunity to study how different population groups adapt. We investigate the impact of this crisis on the evolution of perceived stress in the short and medium term in Switzerland, using data of the Swiss Household Panel from 2016 to early 2021, which include annual measures of perceived stress and a study between waves, conducted in May and June 2020 at the end of the first semi-lockdown. Using the longitudinal structure of the data with pre-crisis measurements, we estimate pooled OLS, fixed effects and first difference models, which include socio-demographic variables, life events, socio-economic status, work-related variables, stress-reducing resources and restrictions in place.

A Newly Designed High-Strength Tool Steel with High Wear and Corrosion Resistance.

In this study, a newly developed high-strength cast Fe81Cr15V3C1 (wt%) steel with a high resistance against dry abrasion and chloride-induced pitting corrosion is presented. The alloy was synthesized through a special casting process that yielded high solidification rates. The resulting fine, multiphase microstructure is composed of martensite, retained austenite and a network of complex carbides.

Approach to Estimate the Phase Formation and the Mechanical Properties of Alloys Processed by Laser Powder Bed Fusion via Casting.

A high-performance tool steel with the nominal composition Fe85Cr4Mo8V2C1 (wt%) was processed by three different manufacturing techniques with rising cooling rates: conventional gravity casting, centrifugal casting and an additive manufacturing process, using laser powder bed fusion (LPBF). The resulting material of all processing routes reveals a microstructure, which is composed of martensite, austenite and carbides. However, comparing the size, the morphology and the weight fraction of the present phases, a significant difference of the gravity cast samples is evident, whereas the centrifugal cast material and the LPBF samples show certain commonalities leading finally to similar mechanical properties.

Aerosol pH and Ion Activities of HSO and SO in Supersaturated Single Droplets.

Accurate determination of acidity (pH) and ion activities in aqueous droplets is a major experimental and theoretical challenge for understanding and simulating atmospheric multiphase chemistry. Here, we develop a ratiometric Raman spectroscopy method to measure the equilibrium concentration of sulfate (SO) and bisulfate (HSO) in single microdroplets levitated by aerosol optical tweezers. This approach enables determination of ion activities and pH in aqueous sodium bisulfate droplets under highly supersaturated conditions.