A5019324933- Astrophysics and Cosmic Phenomena
- Dark Matter and Cosmic Phenomena
- Atmospheric chemistry and aerosols
- Mass Spectrometry Techniques and Applications
- Gamma-ray bursts and supernovae
- Air Quality and Health Impacts
- Atmospheric Ozone and Climate
- Particle Detector Development and Performance
- Neutrino Physics Research
- Atmospheric aerosols and clouds
- Air Quality Monitoring and Forecasting
- Analytical Chemistry and Chromatography
- Advanced Chemical Sensor Technologies
- Radiation Detection and Scintillator Technologies
- Analytical chemistry methods development
- Particle physics theoretical and experimental studies
- Solar and Space Plasma Dynamics
- Atmospheric and Environmental Gas Dynamics
- Nuclear Physics and Applications
- Atomic and Subatomic Physics Research
- Radio Astronomy Observations and Technology
- Earthquake Detection and Analysis
- Lightning and Electromagnetic Phenomena
- Pulsars and Gravitational Waves Research
- Isotope Analysis in Ecology
Institute of High Energy Physics
2017-2025
University of Chinese Academy of Sciences
2007-2025
Chinese Academy of Sciences
2007-2025
Qilu Hospital of Shandong University
2022-2025
Gansu Great Wall Electrical and Electronics Engineering Research Institute
2023-2024
Shanghai Meteorological Bureau
2011-2024
Jinan University
2015-2024
Institute for Nuclear Research
2023
Institute of Physics and Technology
2023
Hebei Normal University
2015-2023
High-energy photons from the Crab Nebula The contains a pulsar that excites surrounding gas to emit high-energy radiation. combination of pulsar's youth and nearby location makes nebula brightest gamma-ray source in sky. LHAASO Collaboration report observations this at energies tera– peta–electron volts, extending spectrum prototypical object. They combine these data with lower model physics emission process. multiwave-length can be explained by synchrotron radiation inverse Compton...
Some gamma-ray bursts (GRBs) have a tera-electron volt (TeV) afterglow, but the early onset of this has not been observed. We report observations with Large High Altitude Air Shower Observatory (LHAASO) bright GRB 221009A, which serendipitously occurred within instrument's field view. More than 64,000 photons >0.2 TeV were detected first 3000 seconds. The flux began several minutes after trigger and then rose to peak ~10 seconds later. This was followed by decay phase, became more rapid ~650...
Abstract We present the first catalog of very-high-energy and ultra-high-energy gamma-ray sources detected by Large High Altitude Air Shower Observatory. The was compiled using 508 days data collected Water Cherenkov Detector Array from 2021 March to 2022 September 933 recorded Kilometer Squared 2020 January September. This represents main result most sensitive large coverage survey sky above 1 TeV, covering decl. −20° 80°. In total, contains 90 with an extended size smaller than 2° a...
The diffuse Galactic γ-ray emission, mainly produced via interactions between cosmic rays and the interstellar medium and/or radiation field, is a very important probe of distribution, propagation, interaction in Milky Way. In this Letter, we report measurements γ from plane 10 TeV 1 PeV energies, with square kilometer array Large High Altitude Air Shower Observatory (LHAASO). Diffuse emissions inner (15°<l<125°, |b|<5°) outer (125°<l<235°, are detected 29.1σ 12.7σ significance,...
Six coker gas oils (CGOs) and three basic fractions extracted from one of the CGOs by 0.1, 0.4, 1 M HCl hydrochloric acid were characterized positive-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) compared to those analyzed chromatography (GC-MS). The ultra high resolving power accuracy MS allow assignment a unique elemental composition each peak in spectrum. Basic nitrogen species class, type, carbon number. spectra at 200−500 Da...
A haze episode occurred on 12 September 2009 in Shanghai, when the mass ratio of PM1.0/PM2.5 (PM: particulate matter) reached 0.8. similar variation hygroscopic growth factor distribution was observed for Aitken mode particles and accumulation particles, implying that enhancement fine caused by local atmospheric processing. The hygroscopicity measurements combination with chemical analysis provided strong support significant contribution (NH4)2SO4 NH4NO3 to episode. molar [NH4 + ]/([NO3 − ]...
This paper reports on the measurement of large-scale anisotropy in distribution cosmic-ray arrival directions using data collected by air shower detector ARGO-YBJ from 2008 January to 2009 December, during minimum solar activity between cycles 23 and 24. In this period, more than 2 × 1011 showers were recorded with energies ∼1 30 TeV. The observed two-dimensional cosmic rays is characterized two wide regions excess deficit, respectively, both relative intensity ∼10−3 respect a uniform flux,...
This study aims to understand the effect of Domestic Emission Control Area (DECA) policy on ambient SO2 and particle components in Shanghai. Online single analysis measurements from 2015 2017 were compared analyze long-term variations before after DECA policy. Our showed that there was a significant decrease by 27-55% implementation The number fraction ship-emitted particles increased along with increase ship traffic activity, but tended contain lower-vanadium content. elemental carbon...
Abstract. The formation of oxalic acid and its mixing state in atmospheric particulate matter (PM) were studied using a single-particle aerosol mass spectrometer (SPAMS) the summer winter 2014 Heshan, supersite rural area Pearl River Delta (PRD) region China. Oxalic-acid-containing particles accounted for 2.5 2.7 % total detected ambient winter, respectively. Oxalic was measured classified as elemental carbon (EC), organic (OC), (ECOC), biomass burning (BB), heavy metal (HM), secondary...
Abstract The first Water Cherenkov detector of the LHAASO experiment (WCDA-1) has been operating since April 2019. data for year have analyzed to test its performance by observing Crab Nebula as a standard candle. WCDA-1 achieves sensitivity 65 mCU per year, with statistical threshold 5 . To accomplish this, 97.7% cosmic-ray background rejection rate around 1 TeV and 99.8% 6 an approximate photon acceptance 50% is achieved after applying algorithm separate gamma-induced showers. angular...
We report the discovery of a UHE gamma-ray source, LHAASO J2108+5157, by analyzing LHAASO-KM2A data 308.33 live days. Significant excess induced showers is observed in both energy bands 25-100 TeV and $\gt$100 with 9.5 sigma 8.5 sigma, respectively. This source not significantly favored as an extensive angular extension smaller than point-spread function KM2A. The measured spectrum from 20 to 200 can be approximately described power-law index -2.83$\pm$ 0.18stat. A harder demanded at lower...
Recently, the LHAASO Collaboration published detection of 12 ultrahigh-energy γ-ray sources above 100 TeV, with highest energy photon reaching 1.4 PeV. The first PeV γ rays from astrophysical may provide a very sensitive probe effect Lorentz invariance violation (LIV), which results in decay high-energy superluminal scenario and hence sharp cutoff spectrum. Two are studied this work. No signature existence LIV is found their spectra, lower limits on scale derived. Our show that first-order...
Abstract. Particulate amines play an important role for the particle acidity and hygroscopicity also contribute to secondary organic aerosol mass. We investigated sources mixing states of particulate using a single-particle mass spectrometer (SPAMS) during summer winter 2014 at rural site in Pearl River Delta, China. Amine-containing particles accounted 11.1 9.4 % total detected individual winter, respectively. Although increase amine-containing counts mostly occurred night, no obvious...
Very recently, the Large High Altitude Air Shower Observatory (LHAASO) reported observation of very early TeV afterglow brightest-of-all-time GRB 221009A, recording highest photon statistics in band ever from a gamma-ray burst. We use this unique to place stringent constraints on an energy dependence speed light vacuum, manifestation Lorentz invariance violation (LIV) predicted by some quantum gravity (QG) theories. Our results show that 95% confidence level lower limits QG scales are...
Abstract. This study describes a high-performance single-particle mass spectrometry (HP-SPAMS) design in detail. The comprehensive improvements the injection system, optical sizing spectrometry, and data acquisition system have improved particle detection efficiency chemical analysis. combination of an aerodynamic concentrator (APC) wide range lenses (ADLs) enables concentration particles 100–5000 nm range. Using APC increases instrument inlet flow by factor 3–5. ion delayed-exaction...
A specific delayed ion extraction (DIE) technique, which combines a standard rectangular pulse with an exponential pulse, was introduced for single particle mass spectrometry (SPMS) instrument, and it can focus ions in wide range results resolution improvement the of studied ions. The experimental indicate that average positive is about 1000 when mass-to-charge ratio (m/z) greater than 70, negative ions, m/z reach 2000. highest resolutions achieved so far are 1260 2400 SPMS, very beneficial...
Abstract This paper reports on the observation of sidereal large-scale anisotropy cosmic rays using data collected by ARGO-YBJ experiment over 5 years (2008–2012). analysis extends previous work limited to period from 2008 January 2009 December, near minimum solar activity between cycles 23 and 24. With new sample, cycle 24 maximum is investigated. A method used improve energy reconstruction, allowing us cover a much wider range, 4 520 TeV. Below 100 TeV, dominated two wide regions,...