Pollution characteristics and potential sources of Peroxyacetyl Nitrate in a petrochemical industrialized City, Northwest China.

Peroxyacetyl Nitrate (CHC(O)ONO, PAN), a typical secondary product of photochemical reactions, is well known to be a better photochemical indicator due to the only secondary photochemical source in the troposphere. Studies on PAN pollution are sparse in northwest China, resulting in a limited understanding of photochemical pollution in recent years. Herein, the measurement of PAN, O, volatile organic compounds (VOCs), NO, other related species, and meteorological parameters were conducted from May 1 to August 31, 2022, at an urban site in Lanzhou.

Synthesis and characterization of potential polycyclic energetic materials using bicyclic triazole and azetidine structures as building blocks.

Exploring the design strategy of new energetic materials is crucial to promote the development of energetic materials. In this study, a method for designing polycyclic energetic materials is proposed by combining the azetidine structure with azobis-1,2,4-triazole or bi-1,2,4-triazole. A series of typical triazolyl polycyclic compounds were designed and synthesized by simple nucleophilic reaction, which included 5,5'-dichloro-3,3'-bis(3,3'-difluoroazetidine)-4,4'-azobis-1,2,4-triazole (1), 5,5'-dichloro-3,3'-bis(3,3'-difluoroazetidine)-4,4'-bi-1,2,4-triazole (2), 5,5'-dichloro-3-(,-dimethyl)-3'-(3,3'-difluoroazetidine)-4,4'-bi-1,2,4-triazole (3) 5,5'-dichloro-3,3'-bis(3,3'-dinitroazetidine)-4,4'-bi-1,2,4-triazole (4), 5,5'-dichloro-3-(,-dimethyl)-3'-(3,3'-dinitroazetidine)-4,4'-bi-1,2,4-triazole (5), and 5,5'-diazido-3,3'-bis(3,3'-difluoroazetidine)-4,4'-azo-1,2,4-triazole (6).

[Reoperation treatment of persistent postoperative secondary hyperparathyroidism].

To evaluate the clinical effect of reoperation in persistent hyperparathyroidism （PHPT） patients after operation of parathyroidectomy combined with autotransplantation（PTX+AT） on secondary hyperparathyroidism （SHPT） . 18 PHPT patients who treated with reoperation after PTX+AT were enrolled in this study during the period from Aug 2012 to Dec 2021 in the Department of Otolaryngology Head and Neck Surgery of Peking University Civil Aviation School of Clinical Medicine, Civil Aviation General Hospital. The remaining parathyroid glands were located by preoperative colour Doppler ultrasonography, radionuclide imaging, enhanced CT and MR imaging in the neck region .

Atmospheric oxidizing capacity in autumn Beijing: Analysis of the O and PM episodes based on observation-based model.

Atmospheric oxidizing capacity (AOC) is the fundamental driving factors of chemistry process (e.g., the formation of ozone (O) and secondary organic aerosols (SOA)) in the troposphere.

A Structural Design Method of 3D Electromagnetic Wave-Absorbing Woven Fabrics.

Based on the wave absorption model of 3D woven fabric and the zero-reflection equations, a new structural design method of 3D electromagnetic (EM) wave-absorbing woven fabrics was obtained. The 3D woven fabrics fabricated by the proposed method had the structure of a bidirectional angle interlock. Continuous S-2 glass fibers were used as the matching layer of this 3D woven fabric, and continuous carbon fibers were used as the absorbing layer.

Sources of ambient non-methane hydrocarbon compounds and their impacts on O formation during autumn, Beijing.

The field observation of 54 non-methane hydrocarbon compounds (NMHCs) was conducted from September 1 to October 20 in 2020 during autumn in Haidian District, Beijing. The mean concentration of total NMHCs was 29.81 ± 11.

Formation mechanisms of nitrous acid (HONO) during the haze and non-haze periods in Beijing, China.

As an important precursor of hydroxyl radical (OH), nitrous acid (HONO) plays a significant role in atmospheric chemistry. Here, an observation of HONO and relevant air pollutants in an urban site of Beijing from 14 to 28 April, 2017 was performed. Two distinct peaks of HONO concentrations occurred during the observation.

Effect of Different Combustion Processes on Atmospheric Nitrous Acid Formation Mechanisms: A Winter Comparative Observation in Urban, Suburban and Rural Areas of the North China Plain.

Atmospheric nitrous acid (HONO) is a dominant precursor of hydroxyl (OH) radicals, and its formation mechanisms are still controversial. Few studies have simultaneously explored effects of different combustion processes on HONO sources. Hereby, synchronous HONO measurement in urban (BJ), suburban (XH) and rural (DBT) areas with different combustion processes is performed in the North China Plain in winter.

A Review of Electromagnetic Shielding Fabric, Wave-Absorbing Fabric and Wave-Transparent Fabric.

As the basic materials with specific properties, fabrics have been widely applied in electromagnetic (EM) wave protection and control due to their characteristics of low density, excellent mechanical properties as well as designability. According to the different mechanisms and application scenarios on EM waves, fabrics can be divided into three types: EM shielding fabric, wave-absorbing fabric and wave-transparent fabric, which have been summarized and prospected from the aspects of mechanisms and research status, and it is believed that the current research on EM wave fabrics are imperfect in theory. Therefore, in order to meet the needs of different EM properties and application conditions, the structure of fabrics will be diversified, and more and more attentions should be paid to the research on structure of fabrics that meets EM properties, which will be conductive to guiding the development and optimization of fabrics.

Different HONO Sources for Three Layers at the Urban Area of Beijing.

Gaseous nitrous acid (HONO) is a crucial precursor of the hydroxyl (OH) radical, which is a "detergent" in the atmosphere. Nowadays, HONO formation mechanisms at polluted urban areas are controversial, which restricts the understanding of atmospheric oxidative capacity and radical cycling. Herein, multiday vertical observation of HONO and NO was simultaneously performed at three heights at the urban area of Beijing for the first time.

Pollution characteristics and potential sources of nitrous acid (HONO) in early autumn 2018 of Beijing.

Nitrous Acid (HONO) is an important precursor of hydroxyl radical (OH) and has significant impacts on the formation of Ozone (O) and Secondary Organic Aerosol (SOA). The atmospheric concentrations of HONO were measured during early autumn in downtown, Beijing (China). This study investigated HONO pollution characteristics and potential sources during day and night.

Tagged sources of short-chain chlorinated paraffins in China's marine environment and fish.

Most emitters of short chain chlorinated paraffins (SCCPs) in China are located in eastern China, posing potential risks to the marine environment and food web. Here we employed a comprehensive atmospheric transport model combined with multiple environmental compartment exchange modules and a marine food web model to simulate levels and risks of SCCPs in the marine environment and fish in the Yellow Sea (YS), East China Sea (ECS), and South China Sea (SCS). Results unveiled a decreasing SCCP level in seawaters and sediments towards offshore.

Spatiotemporal variation of atmospheric nitrated polycyclic aromatic hydrocarbons in semi-arid and petrochemical industrialized Lanzhou City, Northwest China.

Polyurethane foam-based passive air sampler (PUF-PAS) and passive dry deposition sampler (PAS-DD) were adopted, for the first time ever in China, to investigate the atmospheric levels and spatial-temporal distributions of air burdens and dry deposition fluxes of 12 nitrated polycyclic aromatic hydrocarbons (NPAHs) during winter and summer seasons in a multiple site field campaign in a petrochemical industrialized capital city in Northwest China. The results showed that the highest air concentration and dry deposition fluxes of ∑NPAHs occurred at a heavy traffic site among 18 sampling sites in both winter and summer season. The lowest air concentration and dry deposition fluxes were observed at the background site.

Thermogravimetric analysis, kinetic study, and pyrolysis-GC/MS analysis of 1,1'-azobis-1,2,3-triazole and 4,4'-azobis-1,2,4-triazole.

Background: In general, the greater the number of directly linked nitrogen atoms in a molecule, the better its energetic performance, while the stability will be accordingly lower. But 1,1'-azobis-1,2,3-triazole (1) and 4,4'-azobis-1,2,4-triazole (2) show remarkable properties, such as high enthalpies of formation, high melting points, and relatively high stabilities. In order to rationalize this unexpected behavior of the two compounds, it is necessary to study their thermal decompositions and pyrolyses.

Contamination of short-chain chlorinated paraffins to the biotic and abiotic environments in the Bohai Sea.

Short-chain chlorinated paraffins (SCCPs) have been produced and emitted intensively around the Bohai Sea, potentially causing risks to this unique ecosystem and one of primary fishery resources in China and busiest seaways in the world. Little is known about fate, cycling, and sources of SCCPs in the Bohai Sea biotic and abiotic environment. In this study, we combined a marine food web model with a comprehensive atmospheric transport-multiple phase exchange model to quantify SCCPs in the biotic and abiotic environment in the Bohai Sea.

Gridded emission inventory of short-chain chlorinated paraffins and its validation in China.

China produces approximately 20%-30% of the total global chlorinated paraffins (CPs). The establishment of a short-chain CP (SCCP) emission inventory is a significant step toward risk assessment and regulation of SCCPs in China and throughout the globe. This study developed a gridded SCCPs emission inventory with a 1/4° longitude by 1/4° latitude resolution from 2008 to 2012 for China, which was based on the total annual CPs emissions for the nation.

Chemical characterization and source apportionment of PM in a semi-arid and petrochemical-industrialized city, Northwest China.

Daily PM samples were collected in 2014 at a suburban petrochemical industrial site and a downtown site in Lanzhou city, Northwest China. Major chemical components in PM, including water-soluble ions, metal elements, and organic and elemental carbon (OC and EC) were determined. The chemical mass closure method and the ISORROPIA II thermodynamic equilibrium model were used to reconstruct PM mass and quantify the combinations of NH, SO and NO to PM.

The estimation of neurotransmitter release probability in feedforward neuronal network based on adaptive synchronization.

In this paper, we proposed a new approach to estimate unknown parameters and topology of a neuronal network based on the adaptive synchronization control scheme. A virtual neuronal network is constructed as an observer to track the membrane potential of the corresponding neurons in the original network. When they achieve synchronization, the unknown parameters and topology of the original network are obtained.

[Influence of acupuncture of Zusanli (ST 36) on connectivity of brain functional network in healthy subjects].

Objective: To observe the effect of acupuncture of Zusanli (ST 36) on electroencephalogram (EEG) so as to probe into its law in regulating the interconnectivity of brain functional network.

Methods: A total of 9 healthy young volunteer students (6 male, 3 female) participated in the present study. They were asked to take a dorsal position on a test-bed.

Estimating and adjusting abnormal networks with unknown parameters and topology.

The changes of parameters and topology in a complex network often lead to unexpected accidents in complex systems, such as diseases in neural systems and unexpected current in circuit system, so the methods of adjusting the abnormal network back to its normal conditions are necessary to avoid these problems. However, it is not easy to detect the structures and information of each network, even if we can find a network which has the same function as the abnormal network, it is still hard to use it as a reference to adjust the abnormal network because a lot of network information is unknown. In this paper, we design a "bridging network" as an information bridge between a normal network and an abnormal network to estimate and control the abnormal network.