다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Abstract A two-dimensional version of the Pennsylvania State University mesoscale model has been applied to Winter Monsoon Experiment data in order to simulate the diurnally occurring convection observed over the South China Sea. The domain includes a representation of part of Borneo as well as the sea so that the model can simulate the initiation of convection. Also included in the model are parameterizations of mesoscale ice phase and moisture processes and longwave and shortwave radiation with a diurnal cycle. This allows use of the model to test the relative importance of various heating mechanisms to the stratiform cloud deck, which typically occupies several hundred kilometers of the domain. Frank and Cohen's cumulus parameterization scheme is employed to represent vital unresolved vertical transports in the convective area. The major conclusions are: Ice phase processes are important in determining the level of maximum large-scale heating and vertical motion because there is a strong anvil componen...

Numerical study of convection observed during the Winter Monsoon Experiment using a mesoscale two-dimensional model [presentation]

The boundary layer equations for plane, incompressible, and steady flow are 

$$\matrix{ {u{{\partial u} \over {\partial x}} + v{{\partial u} \over {\partial y}} = - {1 \over \varrho }{{\partial p} \over {\partial x}} + v{{{\partial ^2}u} \over {\partial {y^2}}},} \cr {0 = {{\partial p} \over {\partial y}},} \cr {{{\partial u} \over {\partial x}} + {{\partial v} \over {\partial y}} = 0.} \cr }$$

Boundary Layer Theory

This chapter introduces the finite element method (FEM) as a tool for solution of classical electromagnetic problems. Although we discuss the main points in the application of the finite element method to electromagnetic design, including formulation and implementation, those who seek deeper understanding of the finite element method should consult some of the works listed in the bibliography section.

Introduction to the Finite Element Method

The application of mass spectrometric techniques to the realtime measurement and characterization of aerosols represents a significant advance in the field of atmospheric science. This review focuses on the aerosol mass spectrometer (AMS), an instrument designed and developed at Aerodyne Research, Inc. (ARI) that is the most widely used thermal vaporization AMS. The AMS uses aerodynamic lens inlet technology together with thermal vaporization and electron-impact mass spectrometry to measure the real-time non-refractory (NR) chemical speciation and mass loading as a function of particle size of fine aerosol particles with aerodynamic diameters between similar to 50 and 1,000 nm. The original AMS utilizes a quadrupole mass spectrometer (Q) with electron impact (EI) ionization and produces ensemble average data of particle properties. Later versions employ time-of-flight (ToF) mass spectrometers and can produce full mass spectral data for single particles. This manuscript presents a detailed discussion of the strengths and limitations of the AMS measurement approach and reviews how the measurements are used to characterize particle properties. Results from selected laboratory experiments and field measurement campaigns are also presented to highlight the different applications of this instrument. Recent instrumental developments, such as the incorporation of softer ionization techniques (vacuum ultraviolet (VUV) photo-ionization, Li(+) ion, and electron attachment) and high-resolution ToF mass spectrometers, that yield more detailed information about the organic aerosol component are also described. (c) 2007 Wiley Periodicals, Inc.

/pdf/chemical-and-microphysical-characterization-of-ambient-3fnm4sju9e.pdf

Chemical and microphysical characterization of ambient aerosols with the aerodyne aerosol mass spectrometer

Corrigendum to <’Linking indoor particulate matter and black carbon with sick building syndrome symptoms in a public office building’> <[Atmospheric Pollution Research 13 (2022) 101292]>

Temperature and pressure effects on the performance of the portable TSI 3007 condensation particle counter: Implications on ground and aerial observations

Atmospheric pollutants pose a high risk to human health, and therefore it is necessary to capture and preferably remove them from ambient air. In this work, we investigate the intermolecular interaction between the pollutants such as CO, CO2, H2S, NH3, NO, NO2, and SO2 gases with the Zn24 and Zn12O12 atomic clusters, using the density functional theory (DFT) at the meta-hybrid functional TPSSh and LANl2Dz basis set. The adsorption energy of these gas molecules on the outer surfaces of both types of clusters has been calculated and found to have a negative value, indicating a strong molecular-cluster interaction. The largest adsorption energy has been observed between SO2 and the Zn24 cluster. In general, the Zn24 cluster appears to be more effective for adsorbing SO2, NO2, and NO than Zn12O12, whereas the latter is preferable for the adsorption of CO, CO2, H2S, and NH3. Frontier molecular orbital (FMO) analysis showed that Zn24 exhibits higher stability upon adsorption of NH3, NO, NO2, and SO2, with the adsorption energy falling within the chemisorption range. The Zn12O12 cluster shows a characteristic decrease in band gap upon adsorption of CO, H2S, NO, and NO2, suggesting an increase in electrical conductivity. Natural bond orbital (NBO) analysis also suggests the presence of strong intermolecular interactions between atomic clusters and the gases. This interaction was recognized to be strong and noncovalent, as determined by noncovalent interaction (NCI) and quantum theory of atoms in molecules (QTAIM) analyses. Overall, our results suggest that both Zn24 and Zn12O12 clusters are good candidate species for promoting adsorption and, thus, can be employed in different materials and/or systems for enhancing interaction with CO, H2S, NO, or NO2.

https://pubs.acs.org/doi/pdf/10.1021/acsomega.3c01177

Gas-Phase Interaction of CO, CO2, H2S, NH3, NO, NO2, and SO2 with Zn12O12 and Zn24 Atomic Clusters

Abstract. Modern electrochemical gas sensors hold great potential for improving practices in air quality (AQ) monitoring as their low cost, ease
of operation and compact design can enable dense observational networks and
mobile measurements. Despite that, however, numerous studies have shown that
the performance of these sensors depends on a number of factors (e.g.
environmental conditions, sensor quality, maintenance and calibration), thereby adding significant uncertainties in the reported measurements
and large discrepancies from those recorded by reference-grade instruments.
In this work we investigate the performance of electrochemical sensors,
provided by two manufacturers (namely Alphasense and Winsen), for measuring
the concentrations of CO, NO2, O3 and SO2. To achieve that we carried out collocated yearlong measurements with reference-grade
instruments at a traffic AQ monitoring station in Nicosia, Cyprus, where
temperatures ranged from ca. 0 ∘C in the winter to almost 45 ∘C in the summer. The CO sensors exhibit the best performance
among all the ones we tested, having minimal mean relative error (MRE)
compared to reference instruments (ca. −5 %), although a significant
difference in their response was observed before and after the summer
period. At the other end of the spectrum, the SO2 sensors reported
concentration values that were at least 1 order of magnitude higher than
the respective reference measurements (with MREs being more than 1000 %
for Alphasense and almost 400 % for Winsen throughout the entire
measurement period), which can be justified by the fact that the
concentrations of SO2 at our measuring site were below their limit of
detection. In general, variabilities in the environmental conditions (i.e.
temperature and relative humidity) appear to significantly affect the
performance of the sensors. When compared with reference instruments, the CO and NO2 electrochemical sensors provide measurements that exhibit
increasing errors and decreasing correlations as temperature increases (from below 10 to above 30 ∘C) and RH decreases (from >75 %
to below 30 %). Interestingly, the performance of the sensors was affected irreversibly during the hot summer period, exhibiting different responses before and after that, resulting in a signal deterioration that was more than twice that reported by the manufacturers. With the exception of the Alphasense NO2 sensor, all low-cost sensors (LCSs) exhibited measurement uncertainties that were much higher, even at the beginning of our measurement period, compared to those required for qualifying the sensors for indicative air quality measurements according to the respective European Commission (EC) Directive. Overall, our results show that the response of all LCSs is strongly affected by the environmental conditions, warranting further investigations on how they are manufactured, calibrated and employed in the field.


Field evaluation of low-cost electrochemical air quality gas sensors under extreme temperature and relative humidity conditions

(1) The Cyprus Institute, EEWRC, Cyprus (k.neitola@cyi.ac.cy), (2) NOAA Earth System Research Laboratory, Boulder, CO, USA, (3) Institute for Atmospheric and Environmental Sciences, Goethe University, Frankfurt, Germany, (4) Aerosol do.o.o., Ljubljana, Slovenia, (5) Josef Stefan Institute, Ljubliana, Slovenia, (6) 6 Institute of Environmental Physics and Remote Sensing (IUP), University of Bremen, Germany, (7) Center of Marine Environmental Sciences (MARUM), University of Bremen, Germany

George Biskos

Papers

Corrigendum to <’Linking indoor particulate matter and black carbon with sick building syndrome symptoms in a public office building’> <[Atmospheric Pollution Research 13 (2022) 101292]>

Temperature and pressure effects on the performance of the portable TSI 3007 condensation particle counter: Implications on ground and aerial observations

Gas-Phase Interaction of CO, CO2, H2S, NH3, NO, NO2, and SO2 with Zn12O12 and Zn24 Atomic Clusters

Field evaluation of low-cost electrochemical air quality gas sensors under extreme temperature and relative humidity conditions

UAV measurements of aerosol properties at the Cyprus institute