scholarly journals Technical Note: Real-Time Diagnosis of the Hygroscopic Growth Micro-Dynamics of Nanoparticles with Two-Dimensional Correlation Infrared Spectroscopy

2021 ◽  
Author(s):  
Xiuli Wei ◽  
Haosheng Dai ◽  
Huaqiao Gui ◽  
Jiaoshi Zhang ◽  
Yin Cheng ◽  
...  
Keyword(s):  
Phase Transition ◽  
Water Content ◽  
Real Time ◽  
Liquid Water ◽  
Spectroscopic Techniques ◽  
Two Dimensional ◽  
Hygroscopic Growth ◽  
2D Ir ◽  
The Difference ◽  
Ir Spectroscopic

Abstract. Nanoparticles can absorb water to grow up and this will affect the light scattering behavior, cloud condensation nuclei properties, lifetime, and chemical reactivity of these particles. Current techniques usually assume the shapes of nanoparticles to be spherical in calculation of aerosol liquid water content (ALWC), which may result in large uncertainties when the shapes of nanoparticles show large deviations to the spherical assumptions. Furthermore, current techniques are also difficult to identify the intermolecular chemical interactions of phase transition micro-dynamics during nanoparticle deliquescence process because their limited temporal resolutions are unable to capture the complex femtosecond-level intermediate states. In this study, the hygroscopic growth properties of nanoparticles with electrical mobility diameter of approximately 100 nm and their phase transition interaction dynamics on molecular scale are characterized on real time by using the Fourier transform infrared (FTIR) and the two-dimensional correlation infrared (2D-IR) spectroscopic techniques. With the FTIR spectroscopy, we develop a novel real-time method for ALWC by constructing the absorption spectra of liquid water, and realized real-time measurements of water content and dry nanoparticle mass to characterize the hygroscopic growth factors (GF) which show discrepancies to the extended aerosol inorganics model (E-AIM). We further explore the difference that the deliquescence points of sodium nitrate (SN) and oxalic acid (OA) compounds are lower than that of AS by using the 2D-IR spectroscopic analysis technique. We also identify the occurrence sequential order of the hydration interactions and investigate the dynamic deliquescence process of the functional groups for AS and its mixture compounds. Both SN and OA compounds lower the deliquescence point of AS, but only AN can change the hydrolysis reaction mechanism for AS in AS/AN and AS/OA mixtures. This study can not only provide important information with respect to the difference in phase transition point under different conditions, but also improve current understanding of the chemical interaction mechanism between nanoparticles (particularly for organic particles) and medium, which is of great significance for haze control across China.

Quantitative Two-Dimensional Infrared (2D IR) Spectroscopy: Theoretical Development for General and Specific Cases

1995 ◽  
Vol 49 (9) ◽  
pp. 1243-1253 ◽  
Author(s):  
Sanong Ekgasit ◽  
Hatsuo Ishida
Keyword(s):  
Ir Spectroscopy ◽  
Chemical Species ◽  
Quantitative Relationship ◽  
Theoretical Development ◽  
Spectroscopic Techniques ◽  
Two Dimensional ◽  
2D Ir ◽  
Correlation Strength ◽  
The Relationship ◽  
Spectral Intensities

A quantitative two-dimensional correlation analysis for various spectroscopic techniques is introduced. Normalization of the spectral intensities enables two-dimensional infrared (2D IR) spectroscopy to be used for quantitative purposes. As a result of the normalization, the correlation strengths are characterized by the dynamic parameters of the correlated spectral intensities. Relationships between the chemical species associated with peak positions in 2D IR spectra are characterized by both the magnitude and the sign of the correlation strength. The magnitude describes the degree of harmonization, while the sign shows the relationship between the dynamic behaviors of the correlated spectral intensities. The phase spectrum, which indicates the quantitative relationship among the dynamic behavior of the spectral intensities, is also introduced.

scholarly journals Assessment of Deterioration Risk of Maijishan Grotto under the Radiation Difference Based on Heat and Moisture Transfer Model

2021 ◽  
Vol 2069 (1) ◽  
pp. 012082
Author(s):  
R B Wu ◽  
Y Ma ◽  
H R Xie ◽  
S Hokoi ◽  
Y Q Yue ◽  
...  
Keyword(s):  
Thermal Stress ◽  
Water Content ◽  
Moisture Transfer ◽  
Transfer Model ◽  
Two Dimensional ◽  
Architectural Heritage ◽  
Direct Sunlight ◽  
The Difference ◽  
The Buddha ◽  
Heat And Moisture

Abstract The ambient environment of architectural heritage is an important factor affecting its conservation. Two adjacent rows of Buddha statues in Grottoes No. 3 (semi-open) of Maijishan Grotto in Gansu, China, show apparent differences in the degree of deterioration. This study made a monitoring scheme of grottoes microenvironments such as air temperature, relative humidity, radiation, and surface temperature to explore the cause of the difference. A two-dimensional heat and moisture (HAM) transfer model was established and verified to simulate the temperature and humidity on the surface and inside of the Buddha statues. Then, temperature and water content fluctuation and the risks of thermal stress destruction on the surface and near the surface of the Buddha statues were evaluated. The results show that the radiation difference causes thermal stress and water content differences both in heights and in depths. This impact brought by the direct sunlight may contribute to the different deterioration on the two rows of Buddha statues. The eaves shaded the upper row of the Buddha statues much longer than the lower ones. Less severe fluctuation and differences in temperature and water content occur at the middle and upper points. This study evaluates the degradation of Grottoes No. 3 and has guiding significance for its preservation methods.

scholarly journals Stratocumulus Liquid Water Content from Dual-Wavelength Radar

2005 ◽  
Vol 22 (8) ◽  
pp. 1207-1218 ◽  
Author(s):  
Robin J. Hogan ◽  
Nicolas Gaussiat ◽  
Anthony J. Illingworth
Keyword(s):  
Water Content ◽  
Liquid Water ◽  
Wave Attenuation ◽  
Droplet Size Distribution ◽  
Liquid Water Content ◽  
Radar Signal ◽  
Cloud Base ◽  
Liquid Water Path ◽  
Atmospheric Radiation Measurement ◽  
The Difference

Abstract A technique is described to retrieve stratocumulus liquid water content (LWC) using the differential attenuation measured by vertically pointing radars at 35 and 94 GHz. Millimeter-wave attenuation is proportional to LWC and increases with frequency, so LWC can be derived without the need to make any assumptions on the nature of the droplet size distribution. There is also no need for the radars to be well calibrated. A significant advantage over many radar techniques in stratocumulus is that the presence of drizzle drops (those with a diameter larger than around 50 μm) does not affect the retrieval, even though such drops may dominate the radar signal. It is important, however, that there are not significant numbers of drops larger than 600 μm, which scatter outside of the Rayleigh regime at 94 GHz. A lidar ceilometer is used to locate the cloud base in the presence of drizzle falling below the cloud. An accuracy of around 0.04 g m−3 is achievable with averaging over 1 min and 150 m (two range gates), but for the previously suggested frequency pair of 10 and 35 GHz, the corresponding accuracy would be considerably worse at 0.34 g m−3. First, the retrieval of LWC is simulated using aircraft-measured size spectra taken from a profile through marine stratocumulus. Results are then presented from two case studies—one using two cloud radars at Chilbolton in southern United Kingdom, and another using the Cloud Profiling Radar System at the Atmospheric Radiation Measurement site in Oklahoma. The liquid water path from the technique was found to be in good agreement with the values that were obtained from microwave radiometers, with the difference between the two being close to the accuracy of the radiometer retrieval. In the case of well-mixed stratocumulus, the profiles were close to adiabatic.

Distinction of four Dalbergia species by FTIR, 2nd derivative IR, and 2D-IR spectroscopy of their ethanol-benzene extractives

Holzforschung ◽  
2016 ◽  
Vol 70 (6) ◽  
pp. 503-510 ◽  
Author(s):  
Shen-Nan Wang ◽  
Fang-Da Zhang ◽  
An-Min Huang ◽  
Qun Zhou
Keyword(s):  
Ir Spectroscopy ◽  
Common Species ◽  
Gas Chromatography Mass Spectrometry ◽  
Spectroscopic Methods ◽  
Two Dimensional ◽  
2D Ir ◽  
East And Southeast Asia ◽  
Reliable Differentiation ◽  
Spectral Ranges ◽  
Ir Spectroscopic

Abstract Four common species of Dalbergia genus (D. bariensis, D. oliveri, D. cochinchinensis, and D. retusa), which are traded as “Rosewood” or “Hongmu” commonly throughout East and Southeast Asia, were extracted with ethanol-benzene and the extractives were analyzed by means of three IR spectroscopic methods aiming at their chemotaxonomic differentiation. Conventional FTIR and 2nd derivative IR (SD-IR) showed defined spectral ranges, where the differences are pronounced. Two-dimensional correlation infrared (2D-IR) spectroscopy revealed significant auto-peaks suitable for reliable differentiation of the four Dalbergia species. The gas chromatography-mass spectrometry (GC-MS) evaluation of the extractives was also useful. It can be concluded that the analysis of the extractives is the best chemotaxonomic approach for identification of anatomically similar wood species.

scholarly journals Significant contribution of organics to aerosol liquid water content in winter in Beijing, China

2019 ◽  
Author(s):  
Xiaoai Jin ◽  
Yuying Wang ◽  
Zhanqing Li ◽  
Fang Zhang ◽  
Weiqi Xu ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Diurnal Variation ◽  
Water Content ◽  
Liquid Water ◽  
Significant Contribution ◽  
Liquid Water Content ◽  
Coefficient Of Determination ◽  
Urban Site ◽  
Hygroscopic Growth ◽  
Aerosol Chemical Composition

Abstract. The aerosol liquid water content (ALWC), an important component of atmospheric particles, has a significant effect on atmospheric optical properties, visibility and multiphase chemical reactions. In this study, ALWC is determined from aerosol hygroscopic growth factor and particle number size distribution (PNSD) measurements and also simulated by the ISORROPIA II thermodynamic model with measured aerosol chemical composition data at an urban site in Beijing from 8 November to 15 December 2017. Rich measurements made during the experiment concerning virtually all aerosol properties allow us not only to derive the ALWC but also to study the contributions by various species for which little has been done in this region. The simulated ALWC including the contribution of organics and the calculated ALWC are highly correlated (coefficient of determination R2 = 0.92). The ALWC contributed by organics (ALWCOrg) accounts for 30 % ± 22 % of the total ALWC during the sampling period. These results suggest a significant contribution of organics to ALWC, which is rather different from previous studies that showed negligible contributions by organics. Our results also show that ALWC correlates well with the mass concentrations of sulfate, nitrate, and secondary organic aerosols (SOA) (R2 = 0.66, 0.56, and 0.60, respectively). We further noted that accumulation mode particles play a key role in determining ALWC, dominating among all the aerosol modes. ALWC is an exponential function of ambient relative humidity (RH) whose strong diurnal variation influence the diurnal variation of ALWC. However, there is a three-hour lag between the extremes of ALWC and RH values, due to the diurnal variations in PNSD and aerosol chemical composition. Finally, a case study reveals that ALWCOrg plays an important role in the formation of secondary aerosols through multiphase reactions at the initial stage of a heavy haze episode.

Transient 2D IR Correlation Spectroscopy of the Photopolymerization of Acrylic and Epoxy Monomers

1993 ◽  
Vol 47 (9) ◽  
pp. 1337-1342 ◽  
Author(s):  
Tatsuhiko Nakano ◽  
Shigeru Shimada ◽  
Rieko Saitoh ◽  
Isao Noda
Keyword(s):  
Fourier Transform ◽  
Real Time ◽  
Correlation Spectroscopy ◽  
Spectral Intensity ◽  
Two Dimensional ◽  
2D Ir ◽  
Intensity Changes ◽  
Ft Ir ◽  
Arbitrary Waveform ◽  
Reaction Processes

Transient two-dimensional infrared (2D IR) correlation spectroscopy coupled with real-time Fourier transform infrared (RT FT-IR) measurement was used to analyze the reaction processes of photopolymerization systems. Unlike the previously developed 2D IR methods based on sinusoidally varying IR signals, a newly developed 2D correlation formalism applicable to transient spectroscopic signals having an arbitrary waveform was used. By this method, features associated with spectral intensity changes and peak shifts arising from polymerization reactions were clearly observed.

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