Organic-Inorganic Rare-Earth Double Perovskite Ferroelectric with Large Piezoelectric Response and Ferroelasticity for Flexible Composite Energy Harvesters.

Hybrid organic-inorganic perovskite (HOIP) ferroelectric materials have great potential for developing self-powered electronic transducers owing to their impressive piezoelectric performance, structural tunability and low processing temperatures. Nevertheless, their inherent brittle and low elastic moduli limit their application in electromechanical conversion. Integration of HOIP ferroelectrics and soft polymers is a promising solution. In this work, a hybrid organic-inorganic rare-earth double perovskite ferroelectric, [RM3HQ]2RbPr(NO3)6 (RM3HQ = (R)-N-methyl-3-hydroxylquinuclidinium) is presented, which possesses multiaxial nature, ferroelasticity and satisfactory piezoelectric properties, including piezoelectric charge coefficient (d33) of 102.3 pC N-1 and piezoelectric voltage coefficient (g33) of 680 × 10-3 V m N-1. The piezoelectric generators (PEG) based on composite films of [RM3HQ]2RbPr(NO3)6@polyurethane (PU) can generate an open-circuit voltage (Voc) of 30 V and short-circuit current (Isc) of 18 µA, representing one of the state-of-the-art PEGs to date. This work has promoted the exploration of new HOIP ferroelectrics and their development of applications in electromechanical conversion devices.

Stereo-Active Lone Pairs Induced Second Harmonic Generation Responses and Electrocatalytic Activity in Hybrid Material.

The lone pair electrons in the electronic structure of molecules have been a prominent research focus in chemistry for more than a century. Stable s2lone pair electrons significantly influence material properties, including thermoelectric properties, nonlinear optical properties, ferroelectricity, and electro(photo)catalysis.While major advances have been achieved in understanding the influence of lone pair electrons on material characteristics, research on this effect in organic-inorganic hybrid materials is in its initial stage. In this work, we successfully obtained a novel organic-inorganic hybrid material incorporating Ge with 4s2 lone pair electrons, (MeHDabco)2[GeBr3]4-H2O (MeHDabco = N-methyl-1,4-diazabicyclo[2.2.2]octane) (1). Driven by the stereochemically active lone pair electrons on the Ge2+, 1 crystallizes in the noncentrosymmetric space group P21 at room temperature and exhibits good second harmonic generation (SHG) responses. Interestingly, 1 also shows electrocatalytic activity for the hydrogen evolution reaction due to the existence of lone pair electrons on Ge2+ cations. The electrochemical experiment combined with the DFT calculations revealed the lone pair electrons act as both an active site for proton adsorption and facilitate the ionization of water. This work not only emphasizes the important role of lone pair electrons in material properties and functions but also provides new insight for designing novel Ge-based hybrid materials.

Introducing Ferroelasticity into 1D Hybrid Lead Halide Semiconductor by Halogen Substitution Strategy.

Organic-inorganic hybrid lead halide perovskites (OLHPs), represented by (CH3 NH3 )PbI3 , are one of the research focus due to their exceptional performance in optoelectronic applications, and ferroelastic domain walls are benign to their charge carrier transport that is confirmed recently. Among them, the 1D OLHPs feature better stability against desorption and moisture, but related 1D ones possessing ferroelasticity are rarely investigated and reported so far. In this work, the 1D ferroelastic semiconductor (N-iodomethyl-N-methyl-morpholinium)PbI3 ((IDMML)PbI3 ) is prepared successfully by introducing successively halogenate atoms from Cl, Br to I into the organic cation of the prototype (N,N-dimethylmorpholinium)PbI3 ((DMML)PbI3 ). Notably, (IDMML)PbI3 shows the narrow bandgap energy (≈2.34 eV) according to the ultraviolet-visible absorption spectrum and the theoretical calculation, and possesses the evident photoconductive characteristic with the on/off ratio of current of ≈50 under the 405 nm light irradiation. This work provides a new case for the ferroelastic OLHPs and will inspire intriguing research in the field of optoelectronic.

Impact of cirrhosis-related complications on posttransplant survival in patients with acute-on-chronic liver failure.

BACKGROUND: Acute-on-chronic liver failure (ACLF) is a life-threatening syndrome defined as acute decompensation in patients with chronic liver disease. Liver transplantation (LT) is the most effective treatment. We aimed to assess the impact of cirrhosis-related complications pre-LT on the posttransplant prognosis of patients with ACLF. METHODS: This was an observational cohort study conducted between January 2018 and December 2020. Clinical characteristics, cirrhosis-related complications at LT and patient survival post-LT were collected. All liver recipients with ACLF were followed for 1 year post-LT. RESULTS: A total of 212 LT recipients with ACLF were enrolled, including 75 (35.4%) patients with ACLF-1, 64 (30.2%) with ACLF-2, and 73 (34.4%) with ACLF-3. The median waiting time for LT was 11 (4-24) days. The most prevalent cirrhosis-related complication was ascites (78.8%), followed by hepatic encephalopathy (57.1%), bacterial infections (48.1%), hepatorenal syndrome (22.2%) and gastrointestinal bleeding (11.3%). Survival analyses showed that patients with complications at LT had a significantly lower survival probability at both 3 months and 1 year after LT than those without complications (all P < 0.05). A simplified model was developed by assigning one point to each complication: transplantation for ACLF with cirrhosis-related complication (TACC) model. Risk stratification of TACC model identified 3 strata (≥ 4, = 3, and ≤ 2) with high, median and low risk of death after LT (P < 0.001). Moreover, the TACC model showed a comparable ability for predicting the outcome post-LT to the other four prognostic models (chronic liver failure-consortium ACLF score, Chinese Group on the Study of Severe Hepatitis B-ACLF score, model for end-stage liver disease score and Child-Turcotte-Pugh score). CONCLUSIONS: The presence of cirrhosis-related complications pre-LT increases the risk of death post-LT in patients with ACLF. The TACC model based on the number of cirrhosis-related complications pre-LT could stratify posttransplant survival, which might help to determine transplant timing for ACLF.

Two-Step Dielectric Responsive Organic-Inorganic Hybrid Material with Mid-Band Light Emission.

Hybrid organic-inorganic perovskite (HOIP) have received tremendous scientific attention because of the phase transition and photovoltaic properties. However, achieving the special perovskite structure with both two-step dielectric response and luminescence characteristics is rarely reported. Herein, we report an organic-inorganic hybrid perovskite, [(BA)2 ⋅ PbI4 ] (Compound 1, BA=n-butylamine) by introducing flexible organic cations (HBA+ ), with direct mid-band gap as 2.28 eV. Interestingly, this material exhibits two-step reversible dielectric response at 350 K and 460 K (in heating process), respectively. Besides, the photoluminescence was found: it emits charming green light under 365 nm lamp (Photoluminescence quantum yield is 9.52 %). The outstanding two-step dielectric response and luminescence characteristics of this compound might pave the way for the application of dielectric and ferroelectric functional materials in temperature sensors and mechanical switches.

Ferroelasticity in Organic-Inorganic Hybrid Perovskites.

Molecular ferroelastics have received particular attention for potential applications in mechanical switches, shape memory, energy conversion, information processing, and solar cells, by taking advantages of their low-cost, light-weight, easy preparation, and mechanical flexibility. The unique structures of organic-inorganic hybrid perovskites have been considered to be a design platform for symmetry-breaking-associated order-disorder in lattice, thereby possessing great potential for ferroelastic phase transition. Herein, we review the research progress of organic-inorganic hybrid perovskite ferroelastics in recent years, focusing on the crystal structures, dimensions, phase transitions and ferroelastic properties. In view of the few reports on molecular-based hybrid ferroelastics, we look forward to the structural design strategies of molecular ferroelastic materials, as well as the opportunities and challenges faced by molecular-based hybrid ferroelastic materials in the future. This review will have positive guiding significance for the synthesis and future exploration of organic-inorganic hybrid molecular ferroelastics.

Integrated Reversible Thermochromism, High Tc , Dielectric Switch and Narrow Band Gap in One Multifunctional Ferroic.

Organic-inorganic Hybrid (OIH) materials for multifunctional switchable applications have attracted enormous attention in recent years due to their excellent optoelectronic properties and good structural tunability. However, it still remains challenging to fabricate one simple OIH compound with multi-functionals properties, such as dielectric switching, thermochromic properties, semiconductor characteristics and ferroelasticity. Under this context, we successfully synthesized [2-(2-fluorophenyl)ethan-1- ammonium]2 SnBr6 (compound 1), which has a higher phase transition temperature of 427.7 K. Additionally, it exhibits a semiconducting property with an indirect band gap of 2.36 eV. Combining ferroelastic, narrow band gap, thermochromic, and dielectric properties, compound 1 can be considered as a rarely reported multi-functional ferroelastic material, which is expected to give inspiration for broadening the applications in the smart devices field.

Thermographic follow-up of postherpetic neuralgia (PHN) subsequent to Ramsay Hunt syndrome with multicranial nerve (V, VII, VIII and IX) involvement: a case report.

BACKGROUND: Ramsay Hunt syndrome (RHS) is caused by a reactivation of varicella-zoster virus (VZV) infection, and it is characterized by the symptoms of facial paralysis, otalgia, auricular rash, and/or an oral lesion. Elderly patients or immunocompromised patients, deep pain at the initial visit and no prompt treatment are significant predictors of postherpetic neuralgia (PHN). When PHN occurs, especially involved cranial polyneuropathy, multiple modalities should be administered for patients with the intractable PHN. The use of thermography in the follow-up of PHN secondary to RHS with multicranial nerve involvement has not yet been described yet in the literature. CASE PRESENTATION: The patient was a 78-year-old man with the chief complaint of a 3-month history of PHN secondary to RHS with polycranial nerve (V, VII, VIII, and IX) involvement. Multimodality therapy with oral gabapentin, pulsed radiofrequency (PRF) application to the Gasserian ganglion for pain in the trigeminal nerve region, linear-polarized near-infrared light irradiation for pain in the facial nerve region, and 2% lidocaine spray for pain in the glossopharyngeal nerve region was used to the treat patient, and follow-up evaluations included thermography. This comprehensive treatment obviously improved the quality of life, resulting in considerable pain relief, as indicated by a decrease in the numerical rating scale (NRS) score from 9 to 3 and a decrease in thermal imaging temperature from higher to average temperature on the ipsilateral side compared with the contralateral side. Lidocaine spray on the tonsillar branches of the glossopharyngeal nerve resulted in an improvement in odynophagia, and the NRS score decreased from 9 to 0 for glossopharyngeal neuralgia after three applications. CONCLUSION: Although the use of thermography in the follow-up of RHS with multiple cranial nerve (V, VII, VIII, and IX) involvement is very rare, in this patient, thermal imaging showed the efficacy of combination therapy (oral gabapentin, 2% lidocaine sprayed, PRF application and linear-polarized near-infrared light irradiation) and that is a good option for treatment.

Noncentrosymmetric Weyl phase and topological phase transition in bulk MoTe.

Ideal topological materials are those stable materials with less nontrivial band crossing near the Fermi surface and a long Fermi arc. By means of first-principles calculations, here we present that the 3D monochalcogenide molybdenum telluride (Pm-MoTe) without an inversion center shows a type-II Weyl semimetal (WSM) phase which cannot checked by symmetry index method. A total of eight Weyl points (WPs) are found in different quadrants of the Brillouin zone (BZ) of Pm-MoTe, which guarantee a long Fermi arc. The WSM phase is robust against the spin-orbit coupling (SOC) effect because of mirror symmetry and time reversal symmetry. It is also found that a topological phase transition can be tuned by strain. For different types of strain, the number of WPs can be effectively modulated to a minimum number, and their energies could be closer to Fermi level. These findings propose a promising material candidate that partly satisfies the ideal WSM criteria and extends the potential applications of the tunable topological phase.

Activation of AMPK-dependent autophagy in the nucleus accumbens opposes cocaine-induced behaviors of mice.

Cocaine is a strong central nervous system stimulant, which can induce drug addiction. Previous studies have reported that cocaine-induced autophagy is involved in neuroinflammation and cell death. However, the role of autophagy in psychomotor sensitivity to cocaine has not been explored. Here, we reported that D1 receptor -CaMKII-AMPK-FoxO3a signaling pathway was involved in acute cocaine application-induced autophagy in the nucleus accumbens (NAc) both in vitro and in vivo. Furthermore, we found that knockdown of the ATG5 gene in the NAc augmented behavioral response to cocaine, and induction of autophagy in the NAc with rapamycin attenuated cocaine-induced behavioral response, which was coincident with the alterations of dendritic spine density in neurons of NAc. These results suggest that cocaine exposure leads to the induction of autophagy, which is a protective mechanism against behavioral response to cocaine of male mice.

Interpenetrating Liquid-Crystal Polyurethane/Polyacrylate Elastomer with Ultrastrong Mechanical Property.

Liquid-crystal elastomer (LCE) materials, which have been developed and investigated for 4 decades, still lack real industrial applications. The fundamental obstacle is the modest force of LCEs generated in the LC-to-isotropic phase transition process, which is the most important actuation moment. Here, we report an interpenetrating liquid-crystal polyurethane/polyacrylate elastomer material, consisting of one main-chain polyurethane LCE and another liquid-crystal polyacrylate thermoset network, which are simultaneously polymerized. This two-way shape memory material can reversibly shrink/expand under thermal stimulus and show ultrastrong actuation-mechanics properties. With a maximum shrinkage ratio of 86% at 140 °C, which is beyond the LC-to-isotropic phase transition, its actuation blocking stress, actuation work capacity, breaking strength, and elastic modulus reach 2.53 MPa, 1267.7 kJ/m3, 7.9 MPa, and 10.4 MPa, respectively. Such LCE material can lift up a load 30 000 times heavier than its own weight. We hope the outstanding mechanical properties of this interpenetrating polymer network-LCE material would pave the way for real industrial utilizations of LCE-based soft actuators.

Decays of Majorana or Andreev Oscillations Induced by Steplike Spin-Orbit Coupling.

The Majorana zero mode in the semiconductor-superconductor nanowire is one of the promising candidates for topological quantum computing. Recently, in islands of nanowires, subgap-state energies have been experimentally observed to oscillate as a function of the magnetic field, showing a signature of overlapped Majorana bound states. However, the oscillation amplitude either dies away after an overshoot or decays, sharply opposite to the theoretically predicted enhanced oscillations for Majorana bound states. We reveal that a steplike distribution of spin-orbit coupling in realistic devices can induce the decaying Majorana oscillations, resulting from the coupling-induced energy repulsion between the quasiparticle spectra on the two sides of the step. This steplike spin-orbit coupling can also lead to decaying oscillations in the spectrum of the Andreev bound states. For Coulomb-blockade peaks mediated by the Majorana bound states, the peak spacings have been predicted to correlate with peak heights by a π/2 phase shift, which was ambiguous in recent experiments and may be explained by the steplike spin-orbit coupling. Our work will inspire more works to reexamine effects of the nonuniform spin-orbit coupling, which is generally present in experimental devices.

Impact Behavior of Hydrophilic Micron Particles on a Planar Gas-Liquid Interface.

The behavior of hydrophilic micron particles impacting on the gas-liquid interface has been further experimentally studied using a high-speed camera at different surface tensions and dynamic viscosities of liquids. The results show that the impact behavior exhibits suspension and submergence modes, whose boundary cannot be clearly identified because the overlap between the impact velocity ranges occurs because of the unstable pinning of the three-phase contact line on the surface of hydrophilic particles. The liquid properties have little effect on the wettability of hydrophilic particles but greatly influence the hydrodynamic and capillary force exerted on the particles, leading to the expansion of the suspension mode range. In addition, the penetration probability changes little with the decrease in surface tension, while it significantly reduces with the increase in dynamic viscosity. A penetration probability model is predicted as an exponential function of the inertial and supporting forces, and the experimental values agree well with the predicted values. The outcomes of this research will be helpful for understanding the mechanism of particle-interface interaction and providing guidance for enhancing the separation of hydrophilic fine ash via a bubble scrubbing system.

Effects of Se substitution and transition metal doping on the electronic and magnetic properties of a MoSxSe2-x/h-BN heterostructure.

The van der Waals heterostructures created by stacking two monolayer semiconductors have been rapidly developed experimentally and exhibit various unique physical properties. In this work, we investigate the effects of Se atom substitution and 3d-TM atom doping on the structural, electronic, and magnetic properties of the MoSe2/h-BN heterostructure, by using first-principles calculations based on density functional theory (DFT). It is found that Se atom substitution could considerably enhance the band gaps of MoSe2/h-BN heterostructures. With an increase in the substitution concentration, the energy band changes from an indirect to a direct band gap when the substitution concentration exceeds a critical value. For 3d-TM atom doping, it is shown that V-, Mn-, Fe-, and Co-doped systems exhibit a half-metallic state and magnetic behavior, while there is no spin polarization in the Ni-doped case. The results provide a theoretical basis for the development of diluted magnetic semiconductors and spin devices based on the MoSxSe2-x/h-BN heterostructure.

[Study on the Design of Explosive (HNS) Content Analysis System Based on THz Spectrum Monomer].

HNS quantitative spectral analysis can not be achieved with the existing infrared Fourier transform spectrometer. As a common monomer explosive concerned, quick identification and quantitative analysis of the substance is important, so it is necessary to research and design a HNS detection system based on THz spectroscopy. Transmissive mode was used in the system to calculate the content of HNS. Electro-optic modulator module was introduced in the system, in order to achieve steady and rapid static scanning optical path. In the experiments HNS characteristic absorption peak positions were acquired. With this basis, combined air absorption characteristics of the wavelength band and spectrum data correlation expression was obtained, thus more characteristic wavelengths selected were determined. According to Beer-Lambert law, the function expression of HNS content and coefficient formula were presented. In the experiment different content of HNS sample powder was obtained with chemical configuration method with the content at the standard level. It made HNS sample powder into HNS Sample slice for all HNS samples, and it carried out HNS content testing with MINI-Z Terahertz spectroscopy and the system. Experimental results show that the results of the two methods are similar in the range of 0.10% to 50.00% for HNS content. Their error is less than 5.0% compared to the standard value, and the system has better linearity.

Interactions between N-ethylmaleimide-sensitive factor and GluR2 in the nucleus accumbens contribute to the expression of locomotor sensitization to cocaine.

Many studies have reported a withdrawal-dependent increase in synaptic AMPA receptor (AMPAR) levels in the nucleus accumbens (NAc) of cocaine-sensitized rats; however, the exact relationship between the expression of sensitization and altered AMPAR surface expression in the NAc has not yet been investigated. We demonstrated that the expression of behavioral sensitization was negatively controlled by N-ethylmaleimide-sensitive factor (NSF)-GluR2 interactions in the NAc. The upregulation of NSF-GluR2 interactions, which may be resulted by the increase in NSF S-nitrosylation after withdrawal from cocaine, was associated with the changes in the expression of behavioral sensitization. Disruption of NSF-GluR2 interactions in the NAc with a specific peptide, TAT-pep-R845A, increased the locomotor response of rats to cocaine by decreasing GluR2 surface insertion. In contrast, prevention of GluR2-containing AMPARs removal from synapses with Pep2-EVKI attenuated the expression of behavioral sensitization. Similarly, treatment with the nitric oxide donor, S-Nitroso-N-acetyl-DL-penicillamine (SNAP), attenuated the expression of locomotor sensitization by promoting GluR2 surface expression. This effect was mediated by the binding of S-nitrosylated NSF to GluR2, which promoted the surface expression of AMPARs. Noticeably, exogenous injection of SNAP into NAc also attenuated the expression of cocaine-induced conditioned place preference. Thus, these results indicate that increased NSF-GluR2 interactions in the NAc after withdrawal from cocaine attenuated the expression of behavioral sensitization and serves as a negative regulatory mechanism in drug-exposed individuals.

Regulation of emotional memory by hydrogen sulfide: role of GluN2B-containing NMDA receptor in the amygdala.

As an endogenous gaseous molecule, hydrogen sulfide (H2 S) has attracted extensive attention because of its multiple biological effects. However, the effect of H2 S on amygdala-mediated emotional memory has not been elucidated. Here, by employing Pavlovian fear conditioning, an animal model widely used to explore the neural substrates of emotion, we determined whether H2 S could regulate emotional memory. It was shown that the H2 S levels in the amygdala of rats were significantly elevated after cued fear conditioning. Both intraamygdala and systemic administrations of H2 S markedly enhanced amygdala-dependent cued fear memory in rats. Moreover, it was found that H2 S selectively increased the surface expression and currents of NMDA-type glutamate receptor subunit 2B (GluN2B)-containing NMDA receptors (NMDARs) in lateral amygdala of rats, whereas blockade of GluN2B-containing NMDARs in lateral amygdala eliminated the effects of H2 S to enhance amygdalar long-term potentiation and cued fear memory. These results demonstrate that H2 S can regulate amygdala-dependent emotional memory by promoting the function of GluN2B-containing NMDARs in amygdala, suggesting that H2 S-associated signaling may hold potential as a new target for the treatment of emotional disorders. In our study, the effect of hydrogen sulfide (H2 S) on amygdala-mediated emotional memory was investigated. It was found that H2 S could enhance amygdala-dependent emotional memory and long-term potentiation (LTP) in rats by selectively increasing the function of GluN2B-containing NMDA receptors in the amygdala. These results suggest that H2 S-associated signaling may be a new target for the treatment of emotional disorders.

[Portable High-Precision System for CH4 Concentration Detection in Mines based on the Laser Mode-Hopping].

In order to detect rapid, portable concentration of methane in the mine, meanwhile, the system included a high sensitivity and a long working period, designed differential optical absorption spectroscopy method based on mode-hopping of semiconductor laser, and established wireless detection system for concentration of methane in the mine. Output wavelengths of the semiconductor laser occurred mode-hopping by modulation current of the system, so it obtained the two wavelengths close to the laser, and one is on the characteristic absorption peak of methane, while the other is not substantially absorbed. When the two beams of light were illuminated test chamber, methane concentration of the gas chamber was solved by Bill Lambert law with the difference of the light intensity between the two beams. Light source used DFB single mode semiconductor laser from Japan Anritsu company. Experimental results show that, when the modulation current increased from 20.0 to 60.0 mA, output wavelength occurred mode-hopping when the modulation current reached 48.3 mA, and output wavelength changed to 1 651.020 nm from 1 650.888 nm. By HITRAN spectrum database, it showed that the position of the wavelength 1 650.888 nm can be used for characteristic absorption peaks, while the wavelength 1 651.020 nm was suitable for reference wavelength. On this basis, the standard concentrations of methane gas was tested in the sealed container, test data of the system was compared to the H-BD5GD410-HC portable methane detector. Test results of the system and the H-BD5GD410-HC portable methane detector were similar, but with the constant concentration increased, the detection error of the system is relatively stable, slightly better than the portable methane detector. Detection error of system were less than 0.050%, under the conditions that there were without the use of expensive phase lock or inspection phase circuit, to achieve the accuracy of better than 0.10% concentration of methane detected in the mine.

Administration of Lactobacillus salivarius LI01 or Pediococcus pentosaceus LI05 improves acute liver injury induced by D-galactosamine in rats.

This work investigated the effect of the intragastric administration of five lactic acid bacteria from healthy people on acute liver failure in rats. Sprague-Dawley rats were given intragastric supplements of Lactobacillus salivarius LI01, Lactobacillus salivarius LI02, Lactobacillus paracasei LI03, Lactobacillus plantarum LI04, or Pediococcus pentosaceus LI05 for 8 days. Acute liver injury was induced on the eighth day by intraperitoneal injection of 1.1 g/kg body weight D-galactosamine (D-GalN). After 24 h, samples were collected to determine the level of liver enzymes, liver function, histology of the terminal ileum and liver, serum levels of inflammatory cytokines, bacterial translocation, and composition of the gut microbiome. The results indicated that pretreatment with L. salivarius LI01 or P. pentosaceus LI05 significantly reduced elevated alanine aminotransferase and aspartate aminotransferase levels, prevented the increase in total bilirubin, reduced the histological abnormalities of both the liver and the terminal ileum, decreased bacterial translocation, increased the serum level of interleukin 10 and/or interferon-γ, and resulted in a cecal microbiome that differed from that of the liver injury control. Pretreatment with L. plantarum LI04 or L. salivarius LI02 demonstrated no significant effects during this process, and pretreatment with L. paracasei LI03 aggravated liver injury. To the best of our knowledge, the effects of the three species-L. paracasei, L. salivarius, and P. pentosaceus-on D-GalN-induced liver injury have not been previously studied. The excellent characteristics of L. salivarius LI01 and P. pentosaceus LI05 enable them to serve as potential probiotics in the prevention or treatment of acute liver failure.

[Characteristics and Source Apportionment of VOCs Initial Mixing Ratio in Beijing During Summer].

To clarify the characteristics and source apportionment of the VOCs initial mixing ratio in Beijing in summer, continuous monitoring of VOCs was conducted in the Beijing urban area from May to August 2022, and the initial mixing ratio was calculated using the photochemical ratio method. The results showed that:① during the study period, initial φ(TVOCs) in the Beijing urban area were (30.0 ±11.5)×10-9, in which the proportion of VOCs and alkanes containing oxygen reached 34.2% and 33.2%, respectively. The species with high volume fractions were low carbon substances such as acetone, ethane, acetaldehyde, and propane. ② The initial TVOCs mixing ratio in Beijing showed a slightly unimodal trend, reaching the peak at 11:00 and slightly decreasing in the afternoon. ③ Isoprene, acetaldehyde, n-butanal, and ethylene were the major contributors to the generation of O3, whereas toluene, isoprene, m-paraxylene, and ethylbenzene were the major contributors to the generation of secondary organic aerosols. ④ Based on the initial mixing ratio of PMF analysis, it was found that aging background and secondary sources (30%) contributed the most to VOCs in Beijing, and motor vehicle sources (25%) were the main primary human sources. In addition, solvent and fuel volatile sources contributed 16%, combustion sources contributed 11%, industrial process sources contributed 9%, and natural sources contributed 9%. ⑤ The anthropogenic sources of Beijing were mainly from the eastern and southern regions, whereas the natural sources were from the western and northwestern regions. This research showed that vehicle emissions should be further reduced, and regional joint prevention and control to reduce VOCs in the whole region is an effective means to control VOCs in Beijing.