Morphology and Composition of Insoluble Brown Carbon from Biomass Burning

Biomass burning (BB) is a primary source of brown carbon (BrC) in the atmosphere. In the present work, for the first time, the application of an impinger for BrC collection was investigated by conducting BB in a home-built setup. UV–vis, fluorescence, and IR measurements indicated that BrC samples collected by the impinger method have the same properties as those collected by the quartz filter method. In addition to exhibiting good BrC collection performance, the impinger was proven to be effective in concentrating methanol-insoluble substances from the smoke plume. Although elemental analysis and IR spectroscopy revealed that the insoluble substances were mainly composed of plant fibers, the fluorescence emission results showed the presence of BrC, and STEM analysis revealed that BrC was characterized by particles strung on wire-like plant fibers

Volatility of Cl-Initiated C₁₂–C₁₄ <i>n</i>‑Alkylcyclohexane Secondary Organic Aerosol: Effects of NO_<i>x</i> and Photoaging

Long-chain alkanes are important components of intermediate-volatility organic compounds, especially for C12–C14 cyclic compounds. In this study, we focus on the volatilities of C12–C14 n-alkylcyclohexane secondary organic aerosol (SOA) initiated by Cl atoms and investigate the influence of NOx, aging time, precursors, and SOA mass loading. Dilution and precursors seem to have little effect on the SOA volatility. Low-volatility organic compounds (LVOCs) account for a dominant part of SOA volatility distribution. Due to the presence of NOx, more fractions of extremely low-volatility OCs (ELVOCs) and a higher carbon oxidation state (OS̅C) result in a decrease in the SOA volatility. During the aging period, the fraction of ELVOCs increased, and semi-volatile organic compounds (SVOCs) decreased simultaneously. Even after 9 h of photoaging, the particle fractions of ELVOCs exceeded those of SVOCs to be the second largest part following LVOCs under high-NOx conditions. The particle-phase oligomerization is the dominant way that influenced the SOA volatility during the photoaging period, according to the product analysis. This study emphasizes the importance of Cl-initiated alkane SOA in the polluted region with high NOx levels

Gas-Phase Generation and Electronic Structure Investigation of Chlorosulfanyl Thiocyanate, ClSSCN

The chlorosulfanyl thiocyanate molecule, ClSSCN, was generated in the gas phase through heterogeneous reaction of SCl2 on the surface of finely powdered AgSCN for the first time. The reaction products were detected and characterized in situ by ultraviolet photoelectron and photoionization mass spectrometry. The molecular geometry and electronic structures of ClSSCN were investigated by a combination of PES experiment and theoretical calculations with the density functional theory and ab initio methods. It was found that the outermost electrons of ClSSCN reside in the Cl−S antibonding π orbital, predominantly localized on the sulfur atom, and the experimental first vertical ionization potential of ClSSCN is 10.20 eV. The dominant fragment SSCN+ in the mass spectrum indicates that the ClSSCN cation prefers the dissociation of the Cl−S bond

Image_2_OPO-CVI: design and implementation of an ocean profiling observation system for wave-powered vertical profiler following an ISO standard.jpeg

This paper presents the design and implementation of an ISO-compliant ocean profiling observation system for wave-powered vertical profiler. This system aims to provide a comprehensive, scalable, and interoperable solution for high-resolution, real-time oceanic observation. As a part of this system, we introduce a wave-powered vertical profiler, known as “Wave Master,” designed to offer enhanced stability and reliability for long-term oceanic data collection. The core of the paper focuses on the Ocean Profiling Observation Complex Virtual Instrument (OPO-CVI), a comprehensive system developed in alignment with ISO 21851 standard. OPO-CVI seamlessly integrates data collection, transmission, storage, and visualization. Specifically, OPO-CVI addresses the challenges of information isolation, system rigidity, and lack of modularity in traditional ocean profiling methods by standardizing data formats and transmission protocols, allowing for seamless integration of new observation elements, and employing a modular architecture for enhanced scalability and reusability. By offering detailed technical insights into the OPO-CVI architecture and its compliance with ISO 21851 standard, this paper aims to contribute significantly to the advancement of standardized, efficient, and reliable oceanic observation systems.</p

Image_1_OPO-CVI: design and implementation of an ocean profiling observation system for wave-powered vertical profiler following an ISO standard.jpeg

This paper presents the design and implementation of an ISO-compliant ocean profiling observation system for wave-powered vertical profiler. This system aims to provide a comprehensive, scalable, and interoperable solution for high-resolution, real-time oceanic observation. As a part of this system, we introduce a wave-powered vertical profiler, known as “Wave Master,” designed to offer enhanced stability and reliability for long-term oceanic data collection. The core of the paper focuses on the Ocean Profiling Observation Complex Virtual Instrument (OPO-CVI), a comprehensive system developed in alignment with ISO 21851 standard. OPO-CVI seamlessly integrates data collection, transmission, storage, and visualization. Specifically, OPO-CVI addresses the challenges of information isolation, system rigidity, and lack of modularity in traditional ocean profiling methods by standardizing data formats and transmission protocols, allowing for seamless integration of new observation elements, and employing a modular architecture for enhanced scalability and reusability. By offering detailed technical insights into the OPO-CVI architecture and its compliance with ISO 21851 standard, this paper aims to contribute significantly to the advancement of standardized, efficient, and reliable oceanic observation systems.</p

Realizing an Excellent Cycle and Rate Performance of LiCoO₂ at 4.55 V by Li Ionic Conductor Surface Modification

As the cathode material of commercial lithium-ion batteries (LIBs) with the highest volumetric energy density, LiCoO2 is still widely used in the field of consumer electronics products. Although LiCoO2 can theoretically deliver 273 mA h g–1, the practical specific capacity is about 185 mA h g–1 (corresponding to the charging voltage of 4.5 V) due to the structural instability of LiCoO2 in the deeply delithiated state. Here, surface modification with the lithium ionic conductor LiAlSiO4 is proposed to improve the electrochemical performance of LiCoO2 at the high cutoff voltage of 4.55 V. The LiAlSiO4-coated LiCoO2 (LAS-LCO) delivers a reversible specific capacity of 209.3 mA h g–1, and the capacity loss is only 10.7% after 100 cycles at the cutoff voltage of 4.55 V. Moreover, LAS-LCO also exhibits an excellent rate capability (specific capacity of 160.0 mA h g–1 at 8C). This superior electrochemical performance results from the effective surface modification with LiAlSiO4, which not only stabilizes the surface structure in the deeply delithiated state as a physical protective layer, but also improves the stability of the bulk structure by forming a solid-solution phase LiAlxCo1–xO2. The functional coating of the lithium ionic conductor LiAlSiO4 is an effective strategy to improve the electrochemical performance of high-voltage (4.55 V) LiCoO2

DataSheet_1_OPO-CVI: design and implementation of an ocean profiling observation system for wave-powered vertical profiler following an ISO standard.csv

This paper presents the design and implementation of an ISO-compliant ocean profiling observation system for wave-powered vertical profiler. This system aims to provide a comprehensive, scalable, and interoperable solution for high-resolution, real-time oceanic observation. As a part of this system, we introduce a wave-powered vertical profiler, known as “Wave Master,” designed to offer enhanced stability and reliability for long-term oceanic data collection. The core of the paper focuses on the Ocean Profiling Observation Complex Virtual Instrument (OPO-CVI), a comprehensive system developed in alignment with ISO 21851 standard. OPO-CVI seamlessly integrates data collection, transmission, storage, and visualization. Specifically, OPO-CVI addresses the challenges of information isolation, system rigidity, and lack of modularity in traditional ocean profiling methods by standardizing data formats and transmission protocols, allowing for seamless integration of new observation elements, and employing a modular architecture for enhanced scalability and reusability. By offering detailed technical insights into the OPO-CVI architecture and its compliance with ISO 21851 standard, this paper aims to contribute significantly to the advancement of standardized, efficient, and reliable oceanic observation systems.</p

Effects of Gas-Particle Partitioning on Refractive Index and Chemical Composition of <i>m</i>‑Xylene Secondary Organic Aerosol

The formation of secondary organic aerosols (SOAs) contains partitioning processes of the oxidation products between the gas and particle phases, which could change the particle-phase composition when particles grow. However, the effects of these processes on the optical properties of SOA remain poorly understood. In this study, we performed smog chamber experiments to investigate the effects of gas-particle partitioning (GPP) on the refractive index (RI) and chemical composition of the <i>m</i>-xylene SOA. Here, we show that the GPP processes, as organic mass increases, can increase the proportions of semivolatile and intermediate-volatility organic compounds (SVOCs and IVOCs) in the particle phase and result in the decrease of SOA RI real part for 0.09 ± 0.02 (without seeds) and 0.15 ± 0.02 (with seeds). This indicates that the SOA optical properties are closely related to the total organic mass and molecular-level composition. In addition, the presence of inorganic seeds promotes the GPP to the particle phase and hence further decreases the RI real part for 0.05 ± 0.02. As pre-existing aerosols are ubiquitous in the ambient atmosphere, it is suggested that there should be a certain correction when the SOA RI of previous laboratory studies is applied to air quality and climate models

Enhancing the Structure and Interface Stability of LiNi_0.83Co_0.12Mn_0.05O₂ Cathode Material for Li-Ion Batteries via Facile CeP₂O₇ Coating

High-energy Ni-rich layered cathode materials (LiNixCoyMn1–x–yO2, x ≥ 0.8) for lithium-ion batteries (LIBs) suffer greatly from cation disorder and poor thermal, structure, and interface stability, causing an unsatisfactory cycle and safety performance. Herein, cerium pyrophosphate (CeP2O7, abbreviated as CPPO) was coated on the secondary particle surface of LiNi0.83Co0.12Mn0.05O2 via a facile PEG assisted aqueous deposition method. Compared with the bare material, lower cation disorder occurs in the modified sample due to lower Ni2+ content. A well-ordered CPPO crystalline coating layer could be observed on the particle surface. Suppressed structural deterioration due to more stable interface properties leads to better rate capability. Also, better thermal stability has been achieved after the surface treatment. The modified sample maintains 92.38% of the initial capacity after 100 cycles at a 2C rate and upper cutoff voltage of 4.3 V. After cycling for 200 cycles at a 1C rate and higher cutoff voltage of 4.4 V, 80.54% of the initial capacity is maintained. In addition, the discharge capacity under a higher rate is greatly improved under the upper cutoff voltage of 4.3/4.5 V

Rapid Sulfate Formation via Uncatalyzed Autoxidation of Sulfur Dioxide in Aerosol Microdroplets

Severe winter haze events in Beijing and North China Plain are characterized by rapid production of sulfate aerosols with unresolved mechanisms. Oxidation of SO2 by O2 in the absence of metal catalysts (uncatalyzed autoxidation) represents the most ubiquitous SO2 conversion pathway in the atmosphere. However, this reaction has long been regarded as too slow to be atmospherically meaningful. This traditional view was based on the kinetic studies conducted in bulk dilute solutions that mimic cloudwater but deviate from urban aerosols. Here, we directly measure the sulfate formation rate via uncatalyzed SO2 autoxidation in single (NH4)2SO4 microdroplets, by using an aerosol optical tweezer coupled with a cavity-enhanced Raman spectroscopy technique. We find that the aqueous reaction of uncatalyzed SO2 autoxidation is accelerated by two orders of magnitude at the high ionic strength (∼36 molal) conditions in the supersaturated aerosol water. Furthermore, at acidic conditions (pH 3.5–4.5), uncatalyzed autoxidation predominately occurs on droplet surface, with a reaction rate unconstrained by SO2 solubility. With these rate enhancements, we estimate that the uncatalyzed SO2 autoxidation in aerosols can produce sulfate at a rate up to 0.20 μg m–3 hr–1, under the winter air pollution condition in Beijing