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Exploring the Venusian lower atmosphere is crucial for studying the atmospheric circulation, surface‐atmosphere interactions, and origin and evolution of the Venusian atmosphere and climate. In this study, we investigate the theoretical capabilities of a downward‐looking passive microwave sounder placed in low Venus orbit to measure the temperature, sulfur dioxide (SO2) and gaseous sulfuric acid (H2SO4(g)) profiles. A nonlinear iterative retrieval algorithm combining a radiative transfer (RT) model and an optimal‐estimation‐based inversion algorithm is established. With the RT model adapted to the Venusian atmosphere, simulations under different atmospheric conditions are performed to optimize the selection of frequency channels. The achievable altitude coverage, vertical resolution and corresponding expected precision of the temperature, SO2 and H2SO4(g) retrievals from the multi‐channel brightness temperature measurements are quantified via retrieval simulations. The temperature can be retrieved from the surface of Venus to an altitude of ∼61 km with a precision of 1–3.5 K and a vertical resolution of 6–15 km. A precision of 10%–35% is expected for SO2 in the ∼12–64 km altitude range and with a vertical resolution of 8–19 km. H2SO4(g) can be retrieved in the ∼36–54 km altitude range with a precision of 10%–30% and a vertical resolution of 6–13 km. Plain Language Summary: The hostile environment and thick sulfuric acid clouds make it difficult to measure the lower atmosphere of Venus. Although many attempts have been made, the existing measurements of the lower atmosphere have provided little information about the spatiotemporal distribution and variation in the temperature and sulfur compound profiles. This limits our understanding of the atmospheric circulation, surface‐atmosphere interactions, and origin and evolution of the Venusian atmosphere and climate. In this study, we investigate the theoretical capabilities of a passive microwave sounder placed in low Venus orbit to measure the temperature, sulfur dioxide (SO2) and gaseous sulfuric acid (H2SO4(g)) profiles. By model simulations, the frequency channel selection and performance simulation for the sounder are completed. Simulation results demonstrate that the sounder could provide the required high‐precision, high‐resolution and vertically resolved observations of the temperature, SO2 and H2SO4(g) in the Venusian lower atmosphere. Key Points: The ability of a microwave radiometer to measure the temperature, SO2 and H2SO4(g) profiles in the Venusian lower atmosphere is verifiedThe measurement channels of the radiometer are determined based on radiative transfer simulationsThe expected precision, vertical resolution and achievable altitude coverage are quantified via retrieval simulations [ABSTRACT FROM AUTHOR]

The high cost of noble metals is one of the key factors hindering the large‐scale application of proton exchange membrane (PEM) water electrolyzer for hydrogen production. Recently, single‐atom catalysts (SACs) with a potential of maximum atom utilization efficiency enable lowering the metal amount as much as possible; unfortunately, their durability remains a challenge under PEM water electrolyzer working conditions. Herein, a highly‐stable alloyed Pt SAC is demonstrated through a plasma‐assisted alloying strategy and applies to a PEM water electrolyzer. In this catalyst, single Pt atoms are firmly anchored onto a Ru support via a robust metal–metal bonding strength, as evidenced by these complementary characterizations. This SAC is used in a PEM water electrolyzer system to achieve a cell voltage as low as 1.8 V at 1000 mA cm−2. Impressively, it can operate over 1000 h without obvious decay, and the catalyst is present in the form of individual Pt atoms. To the knowledge, this will be the first SAC attempt at a cell level toward long‐term PEM. This work paves the way for designing durable SACs employed in the actual working condition in the PEM water electrolyzer. [ABSTRACT FROM AUTHOR]

The real time and accurate estimation of tropical cyclone (TC) surface pressure fields is highly desired in TC forecasting and analysis. Using satellite passive microwave observations over the oceans, the retrieval of TC surface pressure fields was investigated in this study, and a new retrieval algorithm was developed. This algorithm uses brightness temperatures (TBs) and TB anomalies together to accurately estimate TC surface pressure fields. Considering the relative superiority of 118‐GHz radiometers in spatial resolution, this study not only used the measurements of 60‐GHz radiometer Advanced Technology Microwave Sounder (ATMS) but also the 118‐GHz radiometer Microwave Humidity and Temperature Sounder (MWHTS). The TC measurements from July 2015 to September 2018 and the corresponding Global Data Assimilation System (GDAS) Final (FNL) analysis data were used to develop and test the retrieval algorithm. The testing results show that the proposed method can estimate the surface pressure fields of a TC's core area (within a 2° radius from the center) with an accuracy of better than 4.0, 5.0, and 8.0 hPa for tropical depressions and tropical storms, typhoons or hurricanes, and severe typhoons or major hurricanes, respectively. In addition, an in situ comparison demonstrates that the accuracy of the retrieved central pressure is better than 6.0, 8.0, and 10.0 hPa for tropical depressions and tropical storms, typhoons or hurricanes, and severe typhoons or major hurricanes, respectively. Plain Language Summary: Accurate knowledge of tropical cyclone (TC) surface pressure fields is essential for TC forecasting and analysis. Satellite remote sensing of surface pressure fields is normally accomplished using microwave scatterometers. However, this method cannot provide absolute surface pressure information in real time and the performance is not satisfactory in extremely high wind conditions (wind speed >28 m/s). Here we propose a new method to rapidly and accurately estimate TC surface pressure fields using the observations by spaceborne microwave radiometers. Retrieval experiments for 15 TCs were carried out using data from two satellites. The results were validated against surface pressures from model analyses, yielding close agreement. In addition, the central pressures derived from our new algorithm agree well with in situ data. The performance of the new algorithm suggests that our method can be used operationally to provide real‐time TC surface pressure fields for TC forecasters and analysts. Key Points: A new satellite retrieval algorithm is proposed to accurately estimate surface pressure fields under tropical cyclone conditionsRadiometer‐derived tropical cyclone surface pressure fields agree well with in situ measurementsThe ability of spaceborne microwave radiometers to determine tropical cyclone surface pressure fields is validated [ABSTRACT FROM AUTHOR]

The structure of an alkaline protease from Bacillus subtilis used by a tilapia collagen peptide manufacturer was analyzed, and the technology of the enzyme immobilized by sulfonated polystyrene (SPS) nanoparticles was studied. The particle size distribution, SEM, EDS, TEM, and FT-IR spectroscopy of the carrier before and after immobilization were analyzed. The results showed that the molecular weight of the purified enzyme protein was 31.0 kDa. The amino acid sequence with a consistency of 64.04% and one three-dimensional structure simulation diagram of the purified enzyme protein were obtained by LC-MS-MS, which suggested that the protein might belong to subtilisin. The optimal immobilization conditions were as follows: the volume ratio of the immobilization carrier to the enzyme was 3 : 50 (mL : mL), the immobilized temperature was 25°C, and the system pH was 4.5. Under this condition, the immobilization ratio of collagenase was 73.48%, the specific activity was 274.05 U/μg, and the specific activity of the immobilized enzyme was about 53.74% that of the free enzyme. The average particle size of SPS nanospheres was 155.1 nm. The characterization results of SEM, EDS, TEM, and FT-IR spectroscopy showed that the collagenase was successfully immobilized onto SPS nanospheres. The experimental results also showed that the collagenase could be immobilized effectively under the optimal conditions by using SPS nanospheres, and the operation process was simple, feasible, and of low cost with good prospect of industrial application. [ABSTRACT FROM AUTHOR]

Abstract: Sea surface barometric pressure is one of the few key geophysical variables has not been derived from satellite observations. In this study, we investigate the retrieval of sea surface barometric pressure from passive microwave observations. The direct relationship between surface barometric pressure and upward‐emitted brightness temperature observed by a microwave radiometer is deduced and validated. A statistical retrieval algorithm based on the back‐propagation (BP) neural networks is proposed to estimate sea surface barometric pressure using the observations from the Advanced Technology Microwave Sounder (ATMS) onboard the Suomi‐National Polar‐Orbiting Operational Environmental Satellite System Preparatory Project (SNPP) satellite. In situ buoy measurements and reanalysis data are used to assess the retrieval performance. Experimental results show that the proposed retrieval algorithm can estimate sea surface barometric pressure over mid‐to‐low latitude areas ( 40 ° S − 40 ° N) with the root mean square errors of less than 2.0, 3.0, and 3.5 hPa for clear‐sky, cloudy, and rainy conditions, respectively. Several tropical cyclone retrieval experiments also show that the proposed retrieval algorithm behaves well under high wind conditions (15 m/s < wind speed < 28 m/s). [ABSTRACT FROM AUTHOR]