Fine structure of the isoscalar giant quadrupole resonance inSi28andAl27

Usman, I. T.,Buthelezi, Z.,Carter, J.,Cooper, G. R. J.,Fearick, R. W.,Fö,rtsch, S. V.,Fujita, H.,Fujita, Y.,von Neumann-Cosel, P.,Neveling, R.,Papakonstantinou, P.,Pysmenetska, I.,Richter, A.,Roth American Physical Society 2016 Physical Review C Vol.94 No.2

<P>The isoscalar giant quadrupole resonance in Si-28 and Al-27 has been investigated with high-energy-resolution proton inelastic scattering at E-p = 200 MeV and at scattering angles close to the maximum of Delta L = 2 angular distributions with the K600 magnetic spectrometer of iThemba LABS, South Africa. Characteristic scales are extracted from the observed fine structure with a wavelet analysis and compared for Si-28 with random-phase approximation and second random phase approximation calculations with an interaction derived from the Argonne V18 potential by a unitary transformation. A recent extension of the method to deformed nuclei provides the best description of the data, suggesting the significance of Landau damping.</P>

Near-Band-Edge Photoluminescence Spectroscopy of ZnO Nanowires Embedded in Polymers

J.-P. Richters,T. Voss,L. Wischmeier,I. Ruckmann,J. Gutowski 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.5

We report on studies of the low-temperature photoluminescence of ZnO nanowires embedded in different polymers. The spectra of as-grown and embedded ZnO nanowires are compared. We observe a decrease of the deep-level emission and an increase of the near band-edge emission after the embedding process. The near-band-edge emission of the embedded ZnO nanowires is dominated by a surface exciton band. To explain the spectral changes, we propose a model. We report on studies of the low-temperature photoluminescence of ZnO nanowires embedded in different polymers. The spectra of as-grown and embedded ZnO nanowires are compared. We observe a decrease of the deep-level emission and an increase of the near band-edge emission after the embedding process. The near-band-edge emission of the embedded ZnO nanowires is dominated by a surface exciton band. To explain the spectral changes, we propose a model.

Investigation of NOx emissions and NOx-related chemistry in East Asia using CMAQ-predicted and GOME-derived NO2 columns

Han, K. M.,Song, C. H.,Ahn, H. J.,Park, R. S.,Woo, J. H.,Lee, C. K.,Richter, A.,Burrows, J. P.,Kim, J. Y.,Hong, J. H. Copernicus GmbH 2009 Atmospheric chemistry and physics Vol.9 No.3

<P>Abstract. In this study, NO2 columns from the US EPA Models-3/CMAQ model simulations carried out using the 2001 ACE-ASIA (Asia Pacific Regional Aerosol Characterization Experiment) emission inventory over East Asia were compared with the GOME-derived NO2 columns. There were large discrepancies between the CMAQ-predicted and GOME-derived NO2 columns in the fall and winter seasons. In particular, while the CMAQ-predicted NO2 columns produced larger values than the GOME-derived NO2 columns over South Korea for all four seasons, the CMAQ-predicted NO2 columns produced smaller values than the GOME-derived NO2 columns over North China for all seasons with the exception of summer (summer anomaly). It is believed that there might be some error in the NOx emission estimates as well as uncertainty in the NOx chemical loss rates over North China and South Korea. Regarding the latter, this study further focused on the biogenic VOC (BVOC) emissions that were strongly coupled with NOx chemistry during summer in East Asia. This study also investigated whether the CMAQ-modeled NO2/NOx ratios with the possibly overestimated isoprene emissions were higher than those with reduced isoprene emissions. Although changes in both the NOx chemical loss rates and NO2/NOx ratios from CMAQ-modeling with the different isoprene emissions affected the CMAQ-modeled NO2 levels, the effects were found to be limited, mainly due to the low absolute levels of NO2 in summer. Seasonal variations of the NOx emission fluxes over East Asia were further investigated by a set of sensitivity runs of the CMAQ model. Although the results still exhibited the summer anomaly possibly due to the uncertainties in both NOx-related chemistry in the CMAQ model and the GOME measurements, it is believed that consideration of both the seasonal variations in NOx emissions and the correct BVOC emissions in East Asia are critical. Overall, it is estimated that the NOx emissions are underestimated by ~57.3% in North China and overestimated by ~46.1% in South Korea over an entire year. In order to confirm the uncertainty in NOx emissions, the NOx emissions over South Korea and China were further investigated using the ACE-ASIA, REAS (Regional Emission inventory in ASia), and CAPSS (Clean Air Policy Support System) emission inventories. The comparison between the CMAQ-calculated and GOME-derived NO2 columns indicated that both the ACE-ASIA and REAS inventories have some uncertainty in NOx emissions over North China and South Korea, which can also lead to some errors in modeling the formation of ozone and secondary aerosols in South Korea and North China. </P>

Impact of transport of sulfur dioxide from the Asian continent on the air quality over Korea during May 2005

Lee, C.,Richter, A.,Lee, H.,Kim, Y.J.,Burrows, J.P.,Lee, Y.G.,Choi, B.C. Pergamon Press ; Elsevier [distribution] 2008 Atmospheric environment Vol.42 No.7

The East Asian countries have been affected by atmospheric gaseous pollutants (in particular SO<SUB>2</SUB>) transported from the Asian continent as well as Asian dust storms. For investigation of the impact of these anthropogenic trace gases on local air quality in Korea, ground-based measurements using a Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) system and in situ gas analyzers as well as synoptic meteorological data and scattered sunlight spectra obtained by the satellite-borne instrument, Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) launched on board of Environmental Satellite (ENVISAT) in March 2002, were utilized to retrieve SO<SUB>2</SUB> and trace its transport from the Asian continent to Korea in May 2005. The ground-based measurements were carried out in the region of interest, at Korea Global Watch Observatory (KGAWO) in Korea. Plumes of high SO<SUB>2</SUB> over Chinese industrial areas and their transport to the Korean peninsula were observed in SCIAMACHY data in the period of 21-26 May 2005. Highly increased SO<SUB>2</SUB> was measured by the MAX-DOAS system and in situ gas analyzer in the period of 27-29 May 2005 at KGAWO. These observations are supported by the meteorological results that the air-masses picking up these high SO<SUB>2</SUB> plumes while passing over the Chinese industrial and metropolitan areas were transported to the Korean peninsula. The tropospheric SO<SUB>2</SUB> VCDs over these Chinese industrial and metropolitan areas ranged up to 1.4x10<SUP>17</SUP>molcm<SUP>-2</SUP> in SCIAMACHY data. These SO<SUB>2</SUB> plumes resulted in increased SO<SUB>2</SUB> surface levels of up to 7.8ppbv (measured by an in situ gas analyzer) at KGAWO.

인공위성(SCIAMACHY) 데이터를 이용한 대류권 SO₂, NO₂ 측정

이철규(Chulkyu Lee),Andreas Richter,John P. Burrows,김영준(Young J. Kim) 한국대기환경학회 2008 한국대기환경학회지 Vol.24 No.2

Anthropogenic emissions of nitrogen oxides and sulfur dioxide in Northeast Asia are of great concern because of their impact on air quality and atmospheric chemistry on regional and intercontinental scales. Satellite remote sensing based on DOAS (Differential Optical Absorption Spectroscopy) technique has been preferred to measure atmospheric trace species and to investigate their emission characteristics on regional and global scales. Absorption spectra obtained by the satellite-born instrument, SCIAMACHY (Scanning Imaging Absorption Spectrometer for Atmospheric Chartography) have been utilized to retrieve the information of SO₂ and NO₂ over Northeast Asia. SO₂ levels over Northeast Asia were in order of East China, Yellow Sea, South Sea and Korean Peninsula with mean vertical columns of 1.78(±1.0)×10<SUP>16</SUP>, 1.11(±0.67)×10<SUP>16</SUP>, 0.60(±0.63)×10<SUP>16</SUP>, 0.71(±0.65)×10<SUP>16</SUP> molecules/㎠, respectively. NO₂ levels were in order of East China, Yellow Sea, Korean Peninsula, and South Sea with mean vertical columns of 1.2(±0.56)×10<SUP>16</SUP>, 0.38(±0.19)×10<SUP>16</SUP>, 0.48(±0.28)×10<SUP>16</SUP>, 0.26(±0.16)×10<SUP>16</SUP> molecules/㎠, respectively. High levels of SO₂ and NO₂ were observed over East China, in particular in winter by the contribution of heating fuel combustion exhausts. The SO₂ and NO₂ levels over East China were the highest in January with 34% and 42% higher over the annual means. Low levels of SO₂ ranged over Korean peninsula, while NO₂ levels were relatively high, in particular in winter. The SO₂ and NO₂ levels over Yellow Sea were relatively higher compared to those over Korean peninsula and South Sea, which could be mainly attributed to their transport from East China.

GOME 및 CMAQ NO₂ column 농도의 상호 비교를 통한 동아시아 NO<SUB>x</SUB> 배출량 평가 및 화학반응 연구

한경만,송철한,안현주,박래설,우정헌,이철규,A. Richter,J.P. Burrows,김진영,홍지형 한국대기환경학회 2009 한국대기환경학회 학술대회논문집 Vol.2009 No.5월

GOME 및 CMAQ으로부터 산출된 NO₂ 층적분 농도를 통한 동아시아 NO<SUB>x</SUB> 배출량 평가 및 반응에 관한 연구

한경만,송철한,안현주,이철규,A. Richter,J.P. Burrows,김진영,우정헌,홍지형 한국대기환경학회 2008 한국대기환경학회 학술대회논문집 Vol.- No.-