[en] In this paper, we propose an elastic groundsill beam model with piezoelectric effect considered to assess the interfacial adhesion of ferroelectrics thin films, complemented and validated by nano-indentation fracture test on Pb(Zr_0.52Ti_0.48)O₃ (PZT) thin films. It was observed that the hardness and elastic modulus of thin films depend on the indentation depth. It was also observed from the load-indentation depth curves and atomic force microscopy (AFM) images that the fracture failure of PZT thin films induced by nano-indentations can be divided into three typical stages: no damage, bulging and spallation. The delamination of thin film systems was modeled as an interfacial crack propagation problem, with the energy release rate determined from the elastic groundsill beam model. Good agreement was observed between the indentation load and the radius of the largest imprint. For PZT thin films deposited on single Si substrate with thickness of 350 nm and 450 nm, the energy release rates per unit new crack area are in the range of 3.4∼52.4 J/m² and the phase angles are constant of 13.4 deg. The corresponding mode I and mode II stress intensity factors are in the range of K_I=0.4-1.6MPa·m^1/2 and K_II=0.6-2.2MPa·m^1/2

[en] A highly fluorescent compound, 2,5-di-p-anisyl-isobenzofuran (DABF), was synthesized and used as a dopant to fabricate efficient green electroluminescence (EL) devices. The highest occupied molecular orbital level of DABF suggests that it can be excited either by energy transfer or by direct charge trapping mechanism in the EL devices. Three kinds of devices were fabricated based on different emission mechanisms. A double-layer-doped device with DABF doped in both the hole-transporting layer and the electron-transporting layer of the ITO/NPB/TPBI/Mg:Ag device, where ITO is indium-tin-oxide, NPB is (4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl), and TPBI is (2,2',2''-(1,3,5-benzenetriyl)tris[1-phenyl-1H-benzimidazole]), exhibited greatly enhanced brightness and efficiency comparing to the single-layer-doped devices. The brightness and efficiency enhancements are attributed to a combined contribution of energy transfer and direct charge trapping mechanisms in the double-layer-doped device

No abstract available

[en] Probabilistic Safety Assessments (PSAs) have been performed during the design process for GE Hitachi Nuclear Energy (GEH) advanced nuclear power plant designs, including the ABWR and ESBWR advanced LWRs and the advanced sodium-cooled PRISM fast reactor. As part of the process for each plant, PSA results and risk insights have been developed and provisions were included to ensure that PSA modeling assumptions remain valid for future plants referencing the certified designs. The paper discusses the approach followed to analyze, summarize and leverage the PSA results. The PSA results encompass the entire quantified risk profile which includes internal and external severe accident progression analysis and the offsite consequence for at-power and shutdown operating conditions. Risk-informed performance-based programs, especially when applied to advanced reactors with passive design features, can help both licensees and regulators reduce regulatory burdens on safety classified systems and identify opportunities to reclassify/eliminate some safety-related Structures, Systems and Components (SSCs). These programs can relax/eliminate some technical specification requirements with potential to provide significant cost savings during reactor design, construction, and operation phases and can achieve more operational flexibility and optimize maintenance while maintaining the same safety and reliability levels. The US NRC and nuclear industry have conducted public workshops to quantify the benefits of risk-informed performance-based programs, such as the Risk-Informed Completion Time (RICT) and 10 CFR 50.69 program as applied to new reactors. GEH is developing and implementing additional risk-informed performance-based programs for advanced reactors which will make these reactors more viable options in the ever-increasing, competitive global power generation market. (author)

[en] A simple, rapid, cost-efficient, and robust method for separation of ²³⁷Np with an extraction chromatographic column (TOA: tri-n-octylamine on Teflon powder) is outlined in detail and further improved for direct ICP-MS analysis. The column efficiently retained ²³⁷Np in 2 mol L^-1 HNO₃ medium and all of the ²³⁷Np was easily eluted with 0.02 mol L^-1 oxalic acid in 0.16 mol L^-1 HNO₃ at 95 C. The separated solutions were free from most matrix elements and were aspirated into the ICP-MS directly. The decontamination factor for ²³⁸U is more than 10⁴. The instrumental detection limit for ²³⁷Np was 0.46 pg mL^-1, which corresponds to 1.2 x 10^-5 Bq mL^-1. The method is more rapid than traditional radiometric techniques. It is also considered to be more suitable for environmental monitoring than existing methods based on TOA. (orig.)

[en] Human fetal antehypophysis (16 males, 16 females and 4 unknown sex) were cultivated during several weeks. By immunocytochemistry LH gonadotroph cells were determined with anti-hTSH and anti-pLH serum. The release in vitro of LH and FSH was studied by radioimmunoassay. At the first medium change, the quantity of LH and FSH release was related to the gestational age and sex. A rapid decline of both LH and FSH occured over the 10 first days. There after, a basal release of LH was maintained during several months; the release of FSH was generally maintained at the lower limit of the assay. After 1 month in vitro, the level of LH could not be related to the sex. Release of LH was stimulated by synthetic LRF. A significant increase was observed independently of the sex and age of the fetuses studied

[en] The experimental results of microwave FMR studies on ultrathin Fe/GaAs layer structures with various thicknesses of Fe films and GaAs substrates using flip-chip arrangement are reported. First, the major technical aspects of the MBE-grown Fe/GaAs layer structures are summarized. The measured results on the FMR absorption levels versus the thicknesses of the Fe films and the GaAs substrates are then presented. The optimum sample preparation conditions and the thicknesses of Fe film and GaAs substrate for enhancement of the FMR absorption levels in the Fe/GaAs-based bandstop filters are also suggested

[en] Studies of underground miners have consistently shown an increased risk of lung cancer with cumulative exposure to radon-222 and its decay products. Although the deleterious effects of high radon exposure are clear, questions regarding the shape of the exposure-response relationship, and the effects of time factors such as attained age, time since exposure and early age at first exposure, the effect of exposure rate, and the joint association of radon exposure and tobacco use have not yet been fully clarified. This report considers these questions by fitting various models for the relative odds of disease to 74 male lung cancer cases who were diagnosed between 1981 and 1984 and were alive in 1985 and an equal number of controls. All subjects are current or past employees of the Yunnan Tin Corporation, Gejiu City, China, who reside in the local area. Workers were interviewed to obtain information on work history, from which radon exposure in cumulative working level months and arsenic exposure were estimated, and on tobacco use. Results indicate that excess relative risk increases by 1.7% per cumulative working level month [95% confidence interval (0.5, 5.4)]. The linear exposure response relationship significantly declines with year since last radon exposure (P = 0.02). The risk trend also declines with increasing exposure rate (P = 0.001), indicating that long duration of exposure at a low rate may be more deleterious than short duration of exposure at a high rate. A unique aspect of this study population is the very early ages at first radon exposure for many of the workers, about 37% of the radon-exposed workers were first exposed under the age of 13 years. The analysis shows no modification of the radon lung cancer relationship with age at first exposure

[en] Proton exchange membranes (PEMs) are the key components of polymer electrolyte fuel cells (PEFCs). Perfluorinated membranes such as Nafion (DuPont) are used as PEMs predominantly due to their chemical stability, however, the cost of Nafion is still very high. In our previous studies, cost-competitive and high performance PEMs for PEFCs were prepared by radiation induced grafting method. However, it is considered that poor interface properties between the obtained PEM and electrodes induce high interfacial resistance in PEFC. In this study, hybrid PEMs (FNs) were fabricated grafted membrane (s-FEP) with ionomer (Nafion dispersion) which was applied to coat the interface of the PEM and electrodes. The obtained FNs, sulfonated FEP and Nafion 112 were characterized in terms of water uptake, ion exchange capacity (IEC), polarization performance and electrochemical impedance spectroscopy. FNs showed high IEC and water uptake, which would induce the highest ionic conductivity (IC) among tested PEMs. In terms of FNs, the interface between the PEM and electrodes should have been improved because FNs showed the lowest charge transfer resistance among tested PEMs. The high IC and improved interface between the hybrid PEM and electrodes resulted in the best cell performance of FN among tested PEMs. (Author)

[en] We studied the relation of radon exposure and tobacco use to lung cancer among tin miners in Yunnan Province in the People's Republic of China. Interviews were conducted in 1985 with 107 living tin miners with lung cancer and an equal number of age-matched controls from among tin miners without lung cancer to obtain information on lung cancer risk factors including a detailed history of employment and tobacco use. Occupational history was combined with extensive industrial hygiene data to estimate cumulative working level months (WLM) of radon daughter exposure. Similar data were also used to estimate arsenic exposure for control in the analysis. Results indicate an increased risk of lung cancer for water pipe smoking, a traditional form of tobacco use practiced in 91% of cases and 85% of controls. The use of water pipes was associated with a twofold elevation in risk when compared with tobacco abstainers, and a dose-response relation was observed with increasing categories of pipe-year (dose times duration) usage. Estimated WLM of radon exposure varied from 0 to 1,761 among subjects but averaged 515 in cases versus only 244 in controls. Analyses indicated that the persons in the highest quarter of the radon exposure distribution had an odds ratio (OR) = 9.5 (95% confidence interval = 2.7-33.1) compared to persons without radon exposure after controlling for arsenic exposure and other potential confounders. Examination of duration and rate of radon exposure indicated higher risk associated with long duration as opposed to high rate of exposure. Cross-categorizations of radon exposure and tobacco use suggest greater risk associated with radon exposure than tobacco in these workers