Shu-feng Pang

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The in situ infrared spectra of sodium nitrate (NaNO3) and mixed NaNO3/glycerol droplets with organic to inorganic molar ratio (OIR) of 1:8, 1:4, 1:2, 1:1, and 2:1 on the ZnSe substrate were collected using the Fourier transform infrared attenuated total reflection (FTIR-ATR) technique in the RH linearly decreasing process. When the efflorescence process(More)
The efflorescence of an individual KH(2)PO(4) droplet on Teflon substrate was investigated by micro-Raman spectroscopy. With the decrease of relative humidity (RH) from 98.0% to 73.0%, the KH(2)PO(4) droplet lost water gradually and entered into supersaturated state, which was reflected by the area ratio between the water stretching band to the sum of(More)
Tropospheric aerosols are usually complex mixtures of inorganic and organic components, which can influence the hygroscopicities of each other. In this research, we applied confocal Raman technology combined with optical microscopy to investigate the relationship between the hygroscopic behavior and the molecular interactions of mixed(More)
The confocal Raman spectra of mixed phthalic acid/ammonium sulfate (AS) droplets deposited on a polytetrafluoroethylene (PTFE) substrate and a hydrophilic glass substrate are collected. The evolution of the physical state of the mixed droplet deposited on the PTFE substrate at various relative humidities consists of three states: well-mixed liquid state,(More)
In this research, we applied a pulsed RH controlling system and a rapid scan vacuum FTIR spectrometer (PRHCS-RSVFTIR) to investigate hygroscopicity of internally mixed (NH4)2SO4(AS)/citric acid (CA) particles. The water content and efflorescence ratio of AS in the particles and ambient relative humidity (RH) as a function of time were obtained with a(More)
Secondary organic aerosols (SOA) can exist in a glassy or semisolid state under low relative humidity (RH) conditions, in which the particles show nonequilibrium kinetic characteristics with changing ambient RH. Here, we selected internally mixed sucrose/NaNO3 droplets with organic to inorganic molar ratios (OIRs) of 1:8, 1:4, 1:2, and 1:1 as a proxy for(More)
In Poria cocos, triterpene compound and polysaccharides are the main compositions. The heteropolysaccharide was identified as a linear chain of β-(1→3)-d-glucan, which has the strong water absorbing capacity. In order to investigate the effect of water on the structure of Poria cocos, which belongs to a kind of Polyporaceae, the Micro-Fourier transform(More)
The conformational change of poly(vinyl alcohol) has been studied by Fourier transform infrared spectroscopy at various temperatures in the 4000-400 cm(-1) region. The molecular motion and the trans/gauche content are sensitive to the C-H, C-C stretching modes. FTIR spectra show that the I2920/I2849 decreases from 1.84 to 1.0 with increasing temperature,(More)
We report a new method to investigate water transport kinetics in aerosol particles by using rapid scan FTIR spectroscopy combined with a custom-built pulse relative humidity (RH) control system. From real time in situ measurements of RH and composition using high time resolution infrared spectroscopy (0.12 s for one spectrum), and through achieving a high(More)
A novel approach based on a combination of a pulse RH controlling system and a rapid scan vacuum FTIR spectrometer (PRHCS-RSVFTIR) was utilized to investigate dynamic hygroscopicity of two atmospheric aerosols: ammonium sulfate ((NH4)2SO4) and magnesium sulfate (MgSO4). In this approach, rapid-scan infrared spectra of water vapor and aerosols were obtained(More)