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Many real-world optimization problems belong to constrained multi-objective optimization problems (CMOPs). Handling constraints and optimizing objectives are two equally important goals. With effective and efficient population-based meta-heuristics in mind, how to generate the offspring with good convergence and diversity properties is a problem to be solved. Competitive algorithms based on different evolution (DE) metaphors have been proposed to solve CMOPs over years as the performance of the DE is attractive. The creative idea of the proposed algorithm is to design a novel mutation mechanism for handling infeasible solutions and feasible solutions respectively. The mechanism can produce well distributed Pareto optimal front while satisfying all concerning constraints. The performance of the algorithm is evaluated on nineteen benchmark functions. Compared with three representative constraint handling techniques and latest optimization algorithms, experimental results have indicated that the proposed algorithm is an effective candidate for real-world problems. At last, the proposed method is used to solve combined economic emission dispatch (CEED) problem. The experiment results have further validated the efficiency of the method. [ABSTRACT FROM AUTHOR]

• Ambient AHs were measured in eastern China using a mobile platform. • PAHs accounted for 9% of AHs concentration but contributed 23% to SOAP. • Industrial processes were the largest source (44%) of AHs. • Coal combustion was the major source to ambient PAHs. Monocyclic aromatic hydrocarbons (MAHs) and polycyclic aromatic hydrocarbons (PAHs) are both well known as hazardous air pollutants and also important anthropogenic precursors of tropospheric ozone (O 3) and secondary organic aerosols (SOA). In recent years, there have been intensive studies covering MAHs emission from various sources and their behavior under stimulated photochemical conditions. Yet in-situ measurements of PAHs presence and variations in ambient air are sparse. Herein we conducted large geometrical scale mobile measurements for 16 aromatic hydrocarbons (AHs, including 7 MAHs and 9 PAHs) in eastern China between October 27 and November 8, 2019. This unique dataset has allowed for some insights in terms of AHs concentration variations, accompanying chemical composition, source contributions and spatial distributions in eastern China. In general, AHs showed a clear concentration variability between the south and the north of the Yangtze River Delta (YRD). The concentrations of PAHs were approximately 9% of AHs, but contributed 23% of SOA formation potential. Source apportionment via positive matrix factorization (PMF) model revealed that industrial processes as the largest source (44%) of observed AHs, followed by solvent usage (21%), vehicle exhaust (19%), coal combustion (11%) and coking processes (6%). In the perspective of PAHs sources, coal combustion emissions were identified as the dominating factor of a share of 41%–52% in eastern China. Our findings complemented the simultaneously monitoring information of PAHs and MAHs in eastern China, revealed the importance of PAHs to SOA formation and highlighted the necessity of formulating strategies to reduce emissions from anthropogenic sources and reduce risks to human health. [ABSTRACT FROM AUTHOR]

To study atmospheric aerosols, it is essential to build networks that are continuously monitoring particle number size distribution (PNSD). PNSDs are often measured using electrical mobility spectrometers such as scanning mobility particle sizer (SMPS) which includes a neutralizer that conditions the charge state of particles to the pre-assumed distributions. During long-term atmospheric measurement, the charge state can deviate from these assumed values. Measuring both positively and negatively charged particles using a bipolar SMPS helps to capture the variations in aerosol charge state. In this study, we set up a network of bipolar SMPSs at three urban sites and three suburban sites in six Chinese cities. Removing the conventional neutralizer, the bipolar SMPS utilizes the natural aerosol charging process by atmospheric ions. Newly developed aerosol classifiers and detectors were used. Harmonized quality assurance procedures were adopted to assure the performance and the data quality, including laboratory calibrations and intercomparisons, maintenance and monitoring during field measurements, and data inversion and validation. PNSDs are effectively measured by bipolar SMPSs using natural charging process at all six sites. During six months of field measurement in these sites, ion mobility ratios fluctuate significantly while the daily averaged values are stable around 1.0. Particle number concentrations integrated from PNSDs are consistent with those directly measured by the detectors (within a variation of 10%). [Display omitted] • An atmospheric PNSD monitoring network is set up in six Chinese sites. • New instruments and QA procedures are developed and deployed in the network. • Measuring PNSD using natural charging process is verified in various environments. [ABSTRACT FROM AUTHOR]

Organic acids are important contributors to the acidity of atmospheric precipitation, but their existence in the Chinese atmosphere is largely unclear. In this study, twelve atmospheric gaseous organic acids, including C 1 -C 9 alkanoic acids, methacrylic acid, pyruvic acid, and benzoic acid, were observed in the suburb of Wangdu, Hebei Province, a typical rural site in the northern China plain from 16th December, 2018 to 22nd January, 2019, using a Vocus® Proton-Transfer-Reaction time-of-flight mass spectrometer (Vocus PTR-ToF). The quantification of C 2 -C 4 alkanoic acids by the Vocus PTR-ToF was calibrated according to the titration of a NaOH solution by C 2 -C 4 alkanoic acids from home-made permeation sources, and the other organic acids except for formic acid were quantified based on the k cap -sensitivity linearity in the Vocus PTR-ToF, whereas formic acid was not quantified because our instrument setting led to a significant underestimation in its concentration. The average total concentration of eleven gaseous organic acids was 6.96 ± 5.20 ppbv (parts per billion by volume). The average concentration of acetic acid was the highest (3.86 ± 3.00 ppbv), followed by propanoic acid, butyric acid, and methacrylic acid. Domestic straw burning was likely the dominant source of the observed gaseous organic acids according to the good correlations between acetonitrile and organic acids and between particulate K+ and organic acids, and traffic emissions could also have contributed. During episodes with continuously high concentrations of organic acids, short-distance transport dominated in Wangdu according to the backward trajectory analysis. Baoding, Shijiazhuang, and Hengshui areas were the main source areas based on potential source contribution function and concentration weighing track analysis. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: The tectonic setting on both the northern and southern sides of the Dabie Mountains reveals that low-grade metamorphic rocks are important constituents produced by the subduction of the oceanic crust prior to collision between the Sino-Korean and Yangtze cratons. The Zhangbaling Group/Mulanshan schist is a pre-Ordovician oceanic crust. The Sujiahe and Xinyang/Foziling Groups are trench sediments of the Ordovician-Devonian age, and constitute an accretionary prism associated with subduction. The Yangshan coal measures/Meishan Group was a forearc basin sediment of Carboniferous age, and was overthrust by the accretionary prism during collision. The Susong Group is composed of passive continental margin sediments of the Yangtze craton. Backarc basin sediments are postulated to be concealed by Mesozoic–Cenozoic sediments to the north of the Dabie Mountains. High-ultrahigh pressure terrains are exotic tectonic slices exhumed from depths, located between low-grade metamorphic rocks, and disturb the integrity of the earlier subduction orogen. Subduction occurred during the Ordovician to Devonian periods, and collision initiated at the beginning of the Permian. [Copyright &y& Elsevier]

The newly developed Vocus proton-transfer-reaction time-of-flight mass spectrometer (Vocus PTR-TOF) is able to simultaneously detect hundreds of gaseous compounds including a big fraction of volatile organic compounds (VOCs) with outstanding mass resolution and sensitivity. Here, we present an application of Vocus PTR-TOF to monitor gaseous dimethylamine (DMA). The sensitivity towards DMA was improved by tuning the voltage settings of the segmented quadrupole following the molecular ion reactor to obtain a suitable ion transmission window. With the assistance of a permeation tube calibration method, the sensitivity of Vocus PTR-TOF for DMA detection was 2.68 cps pptv−1 at a TOF extraction frequency of 16 kHz and the detection limit was 1.44 pptv at 3σ of the background signal for a 1 min integration time. Laboratory experiments at a series of controlled relative humidity (RH) show that RH of the sample had little influences on the measurement of DMA. Vocus PTR-TOF with this hardware setup was deployed from December 2018 to January 2019 at Wangdu, Hebei Province, China. The temporal profile of C 2 -amines with a high time resolution was obtained, while the detection of VOCs remained successful. Such simultaneous measurements of these compounds are meaningful as these compounds are all relevant to aerosol nucleation and growth. Our results indicate that Vocus PTR-TOF can be a powerful tool in both field and laboratory studies for new particle formation research. [ABSTRACT FROM AUTHOR]

During the Covid-19 outbreak, strict lockdown measures led to notable reductions in transportation-related emissions and significantly altered atmospheric pollution characteristics in urban and suburban areas. In this work, we compare comprehensive online measurements of PM 2.5 major components and organic molecular markers in a suburban location in Shanghai, China before lockdown (Dec. 28, 2019 to Jan. 23, 2020) and during lockdown (Jan. 24 to Feb. 9, 2020). The NO x levels declined sharply by 59% from 44 to 18 ppb during the lockdown, while O 3 rose two times higher to 42 ppb. The PM 2.5 level dropped from 64 to 49 μg m−3 (−24%). The major components all showed reductions, with the reduction of nitrate most prominent at −58%, followed by organics at −19%, and sulfate at −17%. Positive matrix factorization analysis identifies fourteen source factors, including nine primary sources and five secondary sources. The secondary sources consist of sulfate-rich factor, nitrate-rich factor, and three secondary organic aerosol (SOA) factors, with SOA_I being anthropogenic SOA, SOA_II associated with later generation products of organic oxidation, and SOA_III being biogenic SOA. The combined secondary sources contributed to 69% and 63% (40 and 22 μg m−3) of PM 2.5 before and during lockdown, respectively, among which the reductions in the nitrate-rich (−55%) factor was the most prominent. Among primary sources, large reductions (>80%) were observed in contributions from industrial, cooking, and vehicle emissions. Unlike some studies reporting that the restriction during the Covid-19 resulted in enhanced secondary sulfate and SOA formation, we observed decreases in both secondary inorganic and SOA formation despite the overall elevated oxidizing capacity in the suburban site. Our results indicate that the formation change in secondary inorganic and organic compounds in response to substantial reductions in urban primary precursors are different for urban and suburban environments. [Display omitted] • Covid lockdown lowered PM 2.5 and NO x while increased O 3 levels in suburban Shanghai. • Nitrate was the most prominent contributor to PM 2.5 reduction during lockdown. • Lockdown led to reduced PM 2.5 contributions by 8 primary and 5 secondary sources. • Contribution percent drop from industrial and vehicular sources were as high as 87%. • Lockdown effects on SOA formation likely differ in suburban and urban environments. [ABSTRACT FROM AUTHOR]

Abstract: Error reconciliation is a necessary step for quantum key distribution process. In this paper, the correction ability of error reconciliation procedure which is called Winnow protocol is analyzed and estimated, moreover, it gives some expressions about it. The experiment results proved the capability of Winnow protocol are excellent. It is also indicates that the smallest N has the most correction efficiency where from the communication times between the legitimate parties and the data remaining efficiency consideration. [Copyright &y& Elsevier]

Abstract: We present implementation of quantum cryptography with polarization code by wave-guide type phase modulator. At four different low input voltages of the phase modulator, coder encodes pulses into four different polarization states, 45°, 135° linearly polarized or right, left circle polarized, while the decoder serves as the complementary polarizers. [Copyright &y& Elsevier]

Heterogeneous aging of organic aerosols can significantly alter their physicochemical properties and thus their impacts on the radiative balance of the earth system. In this study, kinetics and mechanisms of heterogeneous reactions between suspended squalane particles and hydroxyl (OH) radicals were investigated using a self-made photooxidation flow tube and a high-resolution long time-of-flight chemical ionization mass spectrometer equipped with a Filter Inlet for Gases and AEROsols (FIGAERO-HR-LToF-CIMS). In addition to the measurements of the heterogeneous reaction rate constants for squalane and its multi-generation functionalization products whose carbon backbone are retaining, identification and semi-quantification of functionalization and fragmentation products from OH radical-initiated aging of squalane were carried out, which were utilized to develop a plausible reaction scheme. Our results show that the heterogeneous oxidation mechanism for particulate squalane is similar to those for OH radical initiated-oxidation of gaseous alkanes, but intermolecular hydrogen abstraction, in addition to reactions with O 2 , isomerization, and decomposition, could be an important heterogeneous reaction pathway for alkoxy radicals, leading to the formation of functionalization products of alcohols. The relative abundances of fragmentation products suggest that OH radicals preferably attack the tertiary carbon. The evolution of products indicates that functionalization plays a leading role in the early stage of the reaction and the fragmentation products become more and more important with increased OH exposure. Our study depicts heterogeneous reaction pathways of organic aerosols with OH radicals at the molecular level, and helps to better understand the chemical evolution of complex organic aerosols in the atmosphere. • Hydroxyl radical-initiated aging of particulate squalene was investigated. • A plausible reaction scheme was developed. • Intermolecular hydrogen abstraction is important for particulate alkoxy radicals. • Functionalization plays a leading role in the early stage of the reaction. [ABSTRACT FROM AUTHOR]