- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Polarization Dependence in the Carbon K-edge Photofragmentation of MAPDST Photoresist: an Experimental and Theoretical Study
摘要： The use of tunable soft X-rays from synchrotron radiation (SR) opens the possibility of inducing selective chemical bond scission due to its high localization in a chemical bond. The selective fragmentation of a potential extreme ultraviolet (EUV) resist, poly(4-(methacryloyloxy) phenyldimethylsulfoniumtriflate (MAPDST), was examined using inner shell polarized SR excitation. Selective bond dissociation processes were studied using a combination of carbon K-edge excitation, angle-resolved irradiation, and NEXAFS spectroscopy. Detailed theoretical calculations carried out with the FEFF9 modeling program allowed the interpretation of all the observed experimental features. NEXAFS results indicated that the aromatic group of the polymer lies parallel to the substrate surface. FEFF9 theoretical calculations confirmed the origin of the splitting of the main C 1s →π*C=C resonances observed. The transition C1s → πα*C=C (285.3 eV) can be associated with the four internal carbons of the aromatic ring. The transition C1s → πβ*C=C (286.9 eV) was assigned to the carbon atoms attached to the oxygen and sulfur atoms. According to the theoretical calculations, the origin of the splitting is due to the different absolute energy of C1s. The results showed a strong selective dissociation effect when the excitation energy was tuned to C1s → πα*C=C transition and the electric field vector of the photon was perpendicular to the substrate plane (grazing angle). On the contrary, other transitions were in general less affected. When the SR irradiation angle changed from grazing to normal incidence, the intensity of the C1s → π*C=C transitions was almost unaffected by 285.3 eV photons. The experimental results suggest that site-specific core excitation combined with the direction of the electric field vector of the incidence SR, can efficiently control the localization of the photon energy to produce selective bond dissociation in MAPDST thin films. The results presented here can also be useful to guide new processing lithographic methods for EUVL using the polarization properties of light in ordered polymeric thin films.
关键词： NEXAFS spectroscopy,FEFF9 modeling,selective bond dissociation,synchrotron radiation,polarization dependence,MAPDST photoresist
更新于2025-09-23 15:21:21
-
AIP Conference Proceedings [Author(s) SolarPACES 2017: International Conference on Concentrating Solar Power and Chemical Energy Systems - Santiago, Chile (26–29 September 2017)] - Use of ilmenite and boron waste as a radiation shielding panel
摘要： Ilmenite is an important and interesting metallic oxide mineral. It is a titanium-iron oxide mineral with formula FeTiO3. It is the primary ore of iron and titanium metal. The largest boron mineral reserves in the world are located in Turkey. Each year 900,000 tons of boron waste results from boron production. Boron waste is caused big environmental problem in Turkey. In this study, evaluation of ilmenite and boron waste was performed to investigate the potential use in shielding materials. In this study, incorporation of ilmenite-boron waste has been investigated for its effect on the physical, morphological, mechanical and shielding properties. Several mixtures were prepared with different proportions of ilmenite and boron waste ranging from 0% to 50%. Then they dried and sintered at 1000, 1050 and 1100 (cid:113)C for 2 hours. Sintered samples were characterized.
关键词： environmental problem,ilmenite,boron waste,sintering,radiation shielding
更新于2025-09-23 15:21:21
-
[IEEE 2018 IEEE 17th International Conference on Mathematical Methods in Electromagnetic Theory (MMET) - Kiev (2018.7.2-2018.7.5)] 2018 IEEE 17th International Conference on Mathematical Methods in Electromagnetic Theory (MMET) - Coherent X-ray Radiation by an Ultra-relativistic “Half-bare” Electron in Thin Crystal
摘要： The problem of coherent X-ray radiation by an ultra-relativistic electron with non-Coulomb proper ?eld in ultra-thin crystalline target is considered. The electron is assumed to be stripped of its proper ?eld in the result of preliminary penetration through a thick target. It is shown that in the considered case such radiation characteristics as its angular distribution and total yield are not described by the known text-book formulae and depend on the distance between the targets. Expressions de?ning such characteristics are derived.
关键词： thin crystal,ultra-relativistic electron,non-Coulomb proper ?eld,coherent X-ray radiation
更新于2025-09-23 15:21:21
-
256-Slice Coronary Computed Tomography Angiography Using Low Tube Voltage of 100 KV
摘要： Purpose: To evaluate the image quality and radiation dose of 100 kV with 1000 mAs retrospective electrocardiography (ECG)-gated CCTA protocol, compared to the standard protocol of 120 kV with 800 mAs retrospective ECG-gated CCTA. Material and Methods: We divided 70 patients into two, a reduced dose group with 35 patients (18 M, 17 F; Mean age 56.94 ± 11.51 years) were examined by 100-kV with 1000 mAs retrospective ECG-gated CCTA, and another as a standard group of 35 patients (21, 14 F; Mean age 54.03 ± 9.81 years) were examined by 120-kV with 800 mAs retrospective ECG-gated CCTA. The two blinded radiologists analyzed the image quality of the coronary arteries independently and they accessed subjective and objective image quality. The radiation dose was also measured as effective radiation dose [ED] and was calculated using CT dose volume index [CTDIvol.], dose-length product [DLP] and conversion coefficient for chest (conversion factor k=0.014 mSv mGy-1cm-1). Results: Although the objective image quality of the 100-kV with 1000 mAs was significantly better than the 120-kV with 800 mAs (mean SNR, 36.65 ± 2.95 vs. 33.47 ± 3.86, P<0.0001; mean CNR, 34.27 ± 2.92 vs. 30.62 ± 3.90, P<0.0001). There was no significant variation in the subjective image quality between two groups (mean image score, 4.54 ± 0.37 vs. 4.56 ± 0.25 for radiologist 1, P = 0.781; 4.52 ± 0.25 vs. 4.56 ± 0.25 for radiologist 2, P=0.486). The radiation dose was found to be reduced by 28% with the 100-kV/1000 mAs protocol than with the 120-kV/800 mAs retrospective ECG-gated CCTA (7.87 ± 0.59 vs. 10.95 ± 1.67 mSv, P<0.0001). Conclusion: The protocol of low tube voltage CCTA using 100 kV/1000 mAs retrospective ECG-gated shows significant reduction of the radiation dose without disturbing the subjective image quality of CCTA.
关键词： Coronary CT angiography,Image quality,Radiation dose
更新于2025-09-23 15:21:21
-
[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Validation of Global Land Surface Satellite Phase-2 Surface Broadband Albedo Product
摘要： Surface broadband albedo is a critical parameter in surface radiation budget (SRB), which controls the input, separation, and allocation of the Earth’s surface energy. Recently, a Global LAnd Surface Satellite (GLASS) phase-2 surface broadband albedo product has been generated from the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Advanced Very High Resolution Radiometer (AVHRR) data. In this study, we present a preliminary validation of the GLASS phase-2 surface broadband albedo with the FLUXNET 2015 dataset. The results show that the GLASS phase-2 surface broadband albedo product has a reasonable good accuracy compared with the currently widely used surface albedo dataset, and can provides more reliable estimations of surface albedo at the seasonal snowfall and snowmelt regions. In addition, the GLASS phase-2 surface albedo product is a long-term, global covered (including land and ocean surfaces) dataset, which can be applied in various scenarios of SRB and climate change studies.
关键词： validation,BRDF,FLUXNET,surface radiation budget,Albedo
更新于2025-09-23 15:21:21
-
[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Assessment of two Satellite-Based Land Surface Shortwave Downward Radiation Datasets Over the Tibetan Plateau
摘要： Land surface shortwave downward radiation (SWDR), as one of major components of the surface radiation budget (SRB), plays an important role in the fields of atmospheric, oceanic, and land processes, and ultimately influences the Earth’s climate as well as the matter and energy cycle of the earth system. Currently, regional or global SWDR can be obtained either from reanalysis products or from satellite observations based on statistical or physical-based retrieval models. Although great efforts have been made to assess the applicability and accuracy of those different SWDR datasets, few studies have been conducted to evaluate the performance of the Clouds and the Earth’s Radiant Energy System Synoptic (CERES-SYN) Edition 3a and Himawari-8 SWDR datasets over the Tibetan Plateau. In this study, the both SWDR datasets are validated against in-situ data at 11 ground sites from the China Meteorological Administration (CMA). It is found that the Himawari-8 SWDR product has a slightly higher accuracy in these two SWDR datasets but with a significantly higher spatial resolution (5km). The mean bias is 1.7 W/m2 for CERES-SYN and -1.6 W/m2 for Himawari-8, respectively, the root mean square errors (RMSE) are 31.3 W/m2 for CERES-SYN and 31.2 W/m2 for Himawari-8, respectively. Mean coefficient of determination (R2) of the two datasets are both over 0.8. It is clearly that CERES-SYN tends to overestimate SWDR somewhat while the Himawari-8 has slight underestimation over the Tibetan Plateau. The findings in this paper can be valuable for hydrological, ecological, agrometeorological and biogeochemical applications and researches.
关键词： validation,the Tibetan Plateau,land surface shortwave downward radiation,CERES-SYN,Himawari-8
更新于2025-09-23 15:21:21
-
[IEEE 2018 43rd International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz2018) - Nagoya, Japan (2018.9.9-2018.9.14)] 2018 43rd International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) - On the Contribution of Thermally Generated Surface Plasmon-Polaritons to Heat Radiation of Metal Objects
摘要： We present theoretical and experimental evaluations of the thermally generated surface plasmon polaritons (TSPPs) contribution to heat radiation of metal objects. It is found that this contribution is significant only for the edges of such objects flat facets observed at sliding angles to the facets planes and it is p-polarized. The analytical model for calculation the spectrum and the integral intensity of the entire set of TSPPs arriving to the edge of their sources line has been developed. In contrast to thermal radiation, intensity of TSPPs is proportional to the third rather than fourth degree of temperature, while the TSPP spectrum is shifted towards low frequencies relative to the thermal radiation spectrum.
关键词： thermally generated surface plasmon polaritons,metal objects,heat radiation,p-polarized,analytical model
更新于2025-09-23 15:21:21
-
[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Recent progress in development of radiation tolerant image sensor with field emitter array
摘要： A prototype image sensor is developed using cadmium telluride-based photodiode and a volcano-structured FEA. Radiation tolerance of each component was tested by irradiating gamma-ray using cobalt-60 source. Gamma-ray tolerance of up to 1.2 MGy was confirmed for both FEA and photodiode.
关键词： Radiation tolerant,Image sensor,Cadmium telluride (CdTe),Field emitter array (FEA)
更新于2025-09-23 15:21:21
-
[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Operation of field emitter arrays under high dose rate gamma-ray irradiation
摘要： Robustness of field emitter arrays (FEA) against high dose rate gamma-ray irradiation was confirmed. The current-voltage characteristics of the FEA were investigated in a vacuum vessel developed for in situ measurements under the irradiation. Although slight increase of the gate current was observed under the irradiation, the insulating layer kept the electrical insulation. As a result, FEA showed the almost identical current-voltage characteristics under the 1.3 kGy h-1 gamma-ray irradiation.
关键词： gamma-ray,image sensor,field emitter array,radiation tolerance
更新于2025-09-23 15:21:21
-
Reconstruction and analysis of erythemal UV radiation time series from Hradec Králové (Czech Republic) over the past 50 years
摘要： This paper evaluates the variability of erythemal ultraviolet (EUV) radiation from Hradec Králové (Czech Republic) in the period 1964–2013. The EUV radiation time series was reconstructed using a radiative transfer model and 10 additional empirical relationships with the root mean square error of 9.9 %. The reconstructed time series documented the increase in EUV radiation doses in the 1980s and the 1990s (up to 15 % per decade), which is linked to the steep decline in total ozone (10 % per decade). The changes of cloud cover were the major factor affecting the EUV radiation doses especially in the 1960s, 1970s, and at the beginning of the new millennium. The mean annual EUV radiation doses in the decade 2004–2013 declined by 5 %. The factors affecting the EUV radiation doses differed also according to the chosen integration period (daily, monthly, and annually): solar zenith angle was the most important for daily doses, cloud cover for their monthly means, and the annual means of EUV radiation doses were most influenced by total ozone column. The number of days with very high EUV radiation doses increased by 22 % per decade, the increase was statistically significant in all seasons except autumn. The occurrence of the days with very high EUV doses was influenced mostly by low total ozone column (82 % of days), clear-sky or partly cloudy conditions (74 % of days) and by increased surface albedo (19 % of days). The principal component analysis documented that the occurrence of days with very high EUV radiation doses was much affected by the positive phase of North Atlantic Oscillation with an Azores High promontory reaching over central Europe. In the stratosphere, a strong Arctic circumpolar vortex and also the meridional inflow of ozone-poor air from the south-west were favourable for the occurrence of days with very high EUV radiation doses. This is the first analysis of the relationship between the high EUV radiation doses and macro-scale circulation patterns, and therefore more attention should be given also to other dynamical variables that may affect the solar UV radiation on the Earth surface.
关键词： cloud cover,erythemal ultraviolet radiation,atmospheric circulation patterns,total ozone column,surface albedo
更新于2025-09-23 15:21:21