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In this paper, using concentration data of PM2.5 in 2013 in China and referring to a lot of literature, we preliminary studied the pollution of fine particulate matter and suImnaazed PM2.5 source apportionment in the key cities in China. Our results showed that PM2.5 showed significant spatial and temporal distribution; high surface concentrations of PM2.5 concentrated mainly in the North China Plain, the Sichuan Basin, Yangtze River Delta and other regions; the average annual concentration of PM2.5 was about 80μg/m3 in North China Plain; Seasonal changes in the concentraton of PM2.5 was winter > spring > autumn > summer; fired sources, industrial sources, vehicle exhaust were the major sources of PM2.5 ; motor vehicle exhaust mostly contributed 10% - 30% to PM2.5. This review provides a fundamental undertanding of PM2.5 source apportionment and serves as an important reference for future source apportionment studies to be widely conducted in China. [ABSTRACT FROM AUTHOR]

Umami is essential in food which has garnered attention due to its potential benefits, mainly produced by umami amino acids, nucleotides and peptides. Expanding the mechanism analysis and compiling the available detection information of umami compounds facilitate advance this area. This review initially extracted research focus areas of umami by bibliometric analysis. Then, the specific role of umami contributors in preventing and treating metabolic diseases were introduced. Umami compounds exhibit outstanding performance in various health benefits, including antihypertensive, gut health promotion, enhanced appetite and suppression of obesity, and so on, marking their new perspectives in bioactivity development. Emphasis was placed on elucidating the presentation mechanisms with core metabolism pathways contributing to the umami tastes. The potential umami presentation mechanism and metabolism pathways for key umami compounds were then proposed based on their structural properties. Additionally, current developments in the intelligent detection of umami compounds were reviewed. Intelligent sensors based on umami receptors combined with multivariate statistics provide a more accessible and more intuitive strategy for distinguishing and predicting umami compounds and providing recommendations for further advancements. This review could deepen the understanding of controlling umami taste in food matrices and foster the development of the related industry. [ABSTRACT FROM AUTHOR]

With the intensification of the energy crisis, it is urgent to vigorously develop new environment-friendly energy storage materials. In this work, coexisting ferroelectric and relaxor-ferroelectric phases at a nanoscale were constructed in Sr(Zn 1/3 Nb 2/3 )O 3 (SZN)-modified (Bi 0.5 Na 0.5 ) 0.94 Ba 0.06 TiO 3 (BNBT) ceramics, simultaneously contributing to large polarization and breakdown electric field and giving rise to a superior energy storage performance. Herein, a high recoverable energy density (W rec ) of 5.0 J/cm 3 with a conversion efficiency of 82% at 370 kV/cm, a practical discharged energy density (W d ) of 1.74 J/cm 3 at 230 kV/cm, a large power density (P D ) of 157.84 MW/cm 3 , and an ultrafast discharge speed (t 0.9 ) of 40 ns were achieved in the 0.85BNBT-0.15SZN ceramics characterized by the coexistence of a rhombohedral-tetragonal phase (ferroelectric state) and a pseudo-cubic phase (relaxor-ferroelectric state). Furthermore, the 0.85BNBT-0.15SZN ceramics also exhibited excellent temperature stability (25-120 °C) and cycling stability (10 4 cycles) of their energy storage properties. These results demonstrate the great application potential of 0.85BNBT-0.15SZN ceramics in capacitive pulse energy storage devices.

Context: Conformation generation, also known as molecular unfolding (MU), is a crucial step in structure-based drug design, remaining a challenging combinatorial optimization problem. Quantum annealing (QA) has shown great potential for solving certain combinatorial optimization problems over traditional classical methods such as simulated annealing (SA). However, a recent study showed that a 2000-qubit QA hardware was still unable to outperform SA for the MU problem. Here, we propose the use of quantum-inspired algorithm to solve the MU problem, in order to go beyond traditional SA. We introduce a highly compact phase encoding method which can exponentially reduce the representation space, compared with the previous one-hot encoding method. For benchmarking, we tested this new approach on the public QM9 dataset generated by density functional theory (DFT). The root-mean-square deviation between the conformation determined by our approach and DFT is negligible (less than about 0.5Å), which underpins the validity of our approach. Furthermore, the median time-to-target metric can be reduced by a factor of five compared to SA. Additionally, we demonstrate a simulation experiment by MindQuantum using quantum approximate optimization algorithm (QAOA) to reach optimal results. These results indicate that quantum-inspired algorithms can be applied to solve practical problems even before quantum hardware becomes mature., Methods: The objective function of MU is defined as the sum of all internal distances between atoms in the molecule, which is a high-order unconstrained binary optimization (HUBO) problem. The degree of freedom of variables is discretized and encoded with binary variables by the phase encoding method. We employ the quantum-inspired simulated bifurcation algorithm for optimization. The public QM9 dataset is generated by DFT. The simulation experiment of quantum computation is implemented by MindQuantum using QAOA., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Quantum measurements based on mutually unbiased bases (MUBs) play crucial roles in foundational studies and quantum information processing. It is known that there exist inequivalent MUBs, but little is known about their operational distinctions, not to say experimental demonstration. In this Letter, by virtue of a simple estimation problem, we experimentally demonstrate the operational distinctions between inequivalent triples of MUBs in dimension 4 based on high-precision photonic systems. The experimental estimation fidelities coincide well with the theoretical predictions with only 0.16% average deviation, which is 25 times less than the difference (4.1%) between the maximum estimation fidelity and the minimum estimation fidelity. Our experiments clearly demonstrate that inequivalent MUBs have different information extraction capabilities and different merits for quantum information processing.

To effectively improve air quality during pollution episodes, Beijing released two red alerts in 2015. Here we examined spatio-temporal variations of PM 2.5 concentrations during two alerts based on multiple data sources. Results suggested that PM 2.5 concentrations varied significantly across Beijing. PM 2.5 concentrations in southern parts of Beijing were higher than those in northern areas during both alerts. In addition to unfavorable meteorological conditions, coal combustion, especially incomplete coal combustion contributed significantly to the high PM 2.5 concentrations. Through the CAMx model, we evaluated the effects of emission-reduction measures on PM 2.5 concentrations. Through simulation, emergency measures cut down 10% - 30% of the total emissions and decreased the peaks of PM 2.5 concentrations by about 10-20% during two alerts. We further examined the scenario if emergency measures were implemented several days earlier than the start of red alerts. The results proved that the implementation of emission reduction measures 1-2 days before red alerts could lower the peak of PM 2.5 concentrations significantly. Given the difficulty of precisely predicting the duration of heavy pollution episodes and the fact that successive heavy pollution episodes may return after red alerts, emergency measures should also be implemented one or two days after the red alerts.