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La3+-doped BaSnO3 microtubes (La3+–BaSnO3) have been synthesized by electrospinning method, and the influence of La3+ content on the sensing properties of BaSnO3 for detection of formaldehyde vapor has been investigated. The as-prepared materials have been characterized using XRD, SEM, DSC, XPS, and UV-Vis. The La3+–BaSnO3 sample doped with 4 wt% La exhibited a response as high as 220 to formaldehyde vapor (1000 ppm concentration) along with a very low detection limit of 0.1 ppm at 270 °C, whereas at 140 °C, it exhibited a response of 80 and detection limit of 1 ppm. In addition, the sensor showed excellent selectivity of 57 to formaldehyde at 140 °C when compared with other vapors. Further, the sensor also showed good repeatability and stability over a long period of time suggesting its strong potential as a commercial formaldehyde sensor.
Synchrotron X-radiation provides unique opportunities for diffraction experiments and, therefore, for extending our understanding of the structure - property interplay in catalyst systems. The present status of opportunities and applications of synchrotron X-ray diffraction techniques in the structural chemistry and catalysis science areas is overviewed, and illustrated by selected recent results.
An experiment was conducted to determine the effects of supplementing different amounts of daidzein in a diet on the growth performance, blood biochemical parameters and meat quality of finishing beef cattle. Thirty finishing Xianan steers were distributed in three groups equilibrated by weight and fed three different dietary treatments (concentrate ratio = 80%): (1) control; (2) 500 mg/kg daidzein and (3) 1000 mg/kg daidzein, respectively. Steers were slaughtered after an 80-day feeding trial. Results showed that daidzein supplementation had no effect on the final body weight, average daily gain and feed conversion rate of steers. Steers fed with 1000 mg/kg daidzein had greater dry matter intake than those fed with control diets. Compared with the control group, the 1000 mg/kg daidzein group had a higher fat thickness, lower shear force and lightness. The pH, drip loss, cooking loss, redness (a*), yellowness (b*), moisture, ash, crude protein and intramuscular fat of the Longissimus dorsi muscle were unaffected by daidzein supplementation. Compared with the control group, the 1000 mg/kg daidzein group significantly increased the serum concentrations of insulin, free fatty acid and Glutamic-pyruvic transaminase. The 500 mg/kg daidzein group significantly increased the serum concentration of tetraiodothyronine compared with the control group. Supplemental daidzein did not affect the blood antioxidant ability and blood immune parameters in serum. In conclusion, daidzein supplementation above 500 mg/day modifies feed intake and metabolic and hormonal profile, with positive and negative effects on meat quality.
Theoretical investigations on ferroelectric tunnel junctions (FTJs) with asymmetric electrodes and a composite barrier are presented. A large tunneling electroresistance effect exists for the Pt/SrTiO3/BaTiO3/SrRuO3 junction; on the other hand, exchange of the dielectric and ferroelectric layer stacking sequence can seriously degrade the performance. These correlations are rationalized by the proposed concept of an asymmetry factor, defined as the ratio between the average barrier heights of FTJs for two opposite polarization orientations. We show that a large asymmetry factor is beneficial to FTJs. This work may provide a way to enhance the performance of FTJs by structure engineering.
Using time-resolved laser-scanning confocal microscopy and ultrafast optical pump/THz probe spectroscopy, we measure photoluminescence (PL) and THz-conductivity in perovskite micro-crystals and films. PL quenching and lifetime variations occur from local heterogeneity. Ultrafast THz-spectra measure sharp quantum transitions from excitonic Rydberg states, providing weakly bound excitons with a binding energy of ~13.5 meV at low temperatures. Ab-initio electronic structure calculations give a direct band gap of 1.64 eV, a dielectric constant of ~18, heavy electrons, and light holes, resulting in weakly bound excitons, consistent with the binding energies from the experiment. The complementary spectroscopy and simulations reveal fundamental insights into perovskite light-matter interactions.
Giardia duodenalis is the most common intestinal parasite of humans in the USA, but the risk factors for sporadic (non-outbreak) giardiasis are not well described. The Centers for Disease Control and Prevention and the Colorado and Minnesota public health departments conducted a case-control study to assess risk factors for sporadic giardiasis in the USA. Cases (N = 199) were patients with non-outbreak-associated laboratory-confirmed Giardia infection in Colorado and Minnesota, and controls (N = 381) were matched by age and site. Identified risk factors included international travel (aOR = 13.9; 95% CI 4.9–39.8), drinking water from a river, lake, stream, or spring (aOR = 6.5; 95% CI 2.0–20.6), swimming in a natural body of water (aOR = 3.3; 95% CI 1.5–7.0), male–male sexual behaviour (aOR = 45.7; 95% CI 5.8–362.0), having contact with children in diapers (aOR = 1.6; 95% CI 1.01–2.6), taking antibiotics (aOR = 2.5; 95% CI 1.2–5.0) and having a chronic gastrointestinal condition (aOR = 1.8; 95% CI 1.1–3.0). Eating raw produce was inversely associated with infection (aOR = 0.2; 95% CI 0.1–0.7). Our results highlight the diversity of risk factors for sporadic giardiasis and the importance of non-international-travel-associated risk factors, particularly those involving person-to-person transmission. Prevention measures should focus on reducing risks associated with diaper handling, sexual contact, swimming in untreated water, and drinking untreated water.
The discovery of the first electromagnetic counterpart to a gravitational wave signal has generated follow-up observations by over 50 facilities world-wide, ushering in the new era of multi-messenger astronomy. In this paper, we present follow-up observations of the gravitational wave event GW170817 and its electromagnetic counterpart SSS17a/DLT17ck (IAU label AT2017gfo) by 14 Australian telescopes and partner observatories as part of Australian-based and Australian-led research programs. We report early- to late-time multi-wavelength observations, including optical imaging and spectroscopy, mid-infrared imaging, radio imaging, and searches for fast radio bursts. Our optical spectra reveal that the transient source emission cooled from approximately 6 400 K to 2 100 K over a 7-d period and produced no significant optical emission lines. The spectral profiles, cooling rate, and photometric light curves are consistent with the expected outburst and subsequent processes of a binary neutron star merger. Star formation in the host galaxy probably ceased at least a Gyr ago, although there is evidence for a galaxy merger. Binary pulsars with short (100 Myr) decay times are therefore unlikely progenitors, but pulsars like PSR B1534+12 with its 2.7 Gyr coalescence time could produce such a merger. The displacement (~2.2 kpc) of the binary star system from the centre of the main galaxy is not unusual for stars in the host galaxy or stars originating in the merging galaxy, and therefore any constraints on the kick velocity imparted to the progenitor are poor.
Population decline among Asian horseshoe crabs in Asia is increasingly reported, but knowledge of their population and ecological status in China is limited. We conducted community interviews in 30 fishing villages around Beibu Gulf in Guangxi, China, to collect distribution information about the potential spawning/nursery grounds of Tachypleus tridentatus and Carcinoscorpius rotundicauda, and any imminent threats to their populations. Based on the results from 400 respondents we identified 45 potential spawning/nursery grounds distributed widely along the shores of Beibu Gulf. We visited 10 of these sites and verified the presence of juvenile horseshoe crabs by field surveys. Nearly all respondents reported an overall depletion in horseshoe crab populations from these 45 sites, which they attributed mainly to unsustainable fishing practices. Respondents who reported having seen horseshoe crab mating pairs on shores were mostly older people, which may suggest a considerable reduction in horseshoe crabs coming to the shores to spawn in recent years. The mean daily harvest of adult T. tridentatus offshore, as indicated by fishers, has declined from c. 50–1,000 in the 1990s to 0–30 individuals during 2011–2016. Our Wisdom of Crowds approach, supported by confirmatory field surveys, is a cost-effective method for assessing the population status of horseshoe crabs, and the level of threat they face. Similar approaches with other species are likely to be particularly valuable in the Asia–Pacific region, where well-structured population monitoring is largely unaffordable.
The infrared emission in galaxies is strongly connected to star burst processes, while emission from the intergalactic medium results mainly from dust heated by other luminosity sources. The Virgo cluster provides an extensive region in which the properties of such infrared emission can be studied. Galaxies in the Virgo cluster with dust temperatures of 40 K and masses of dust as small as about 5 × 104M⊙ are detectable at the limit of the IRAS survey (Soifer et al., 1987). The IRAS observations of 196 optically selected galaxies in the Virgo cluster have been studied by Helou et al. (Helou et al., 1988; see also Leggett et al., 1988).
The objective of this investigation was to utilize the first-principles molecular dynamics computational approach to investigate the lithiation characteristics of empty silicon clathrates (Si46) for applications as potential anode materials in lithium-ion batteries. The energy of formation, volume expansion, and theoretical capacity were computed for empty silicon clathrates as a function of Li. The theoretical results were compared against experimental data of long-term cyclic tests performed on half-cells using electrodes fabricated from Si46 prepared using a Hofmann-type elimination–oxidation reaction. The comparison revealed that the theoretically predicted capacity (of 791.6 mAh/g) agreed with experimental data (809 mAh/g) that occurred after insertion of 48 Li atoms. The calculations showed that overlithiation beyond 66 Li atoms can cause large volume expansion with a volume strain as high as 120%, which may correlate to experimental observations of decreasing capacities from the maximum at 1030 mAh/g to 553 mA h/g during long-term cycling tests. The finding suggests that overlithiation beyond 66 Li atoms may have caused damage to the cage structure and led to lower reversible capacities.
Presently, physical limitations are restricting the development of the microelectronic industry driven by Moore's law. To achieve high-performance, small form factor, and lightweight applications, new electronic packaging methods have exceeded Moore's law. This research proposes a double-chip stacking structure in an embedded fan-out wafer-level packaging with double-sided interconnections. The overall reliability of the solder joints and redistributed lines is assessed through finite element analysis. The application of soft lamination material and selection of a carrier material whose coefficient of thermal expansion (CTE) is close to that of the printed circuit board can effectively enhance the reliability of solder joints over more than 1,000 cycles. A trace/pad junction whose direction is parallel to the major direction of the CTE mismatch is recommended, and the curved portion of trace lines can absorb the expansion of metal lines and filler material. Design-on-simulation methodology is necessary to develop novel packaging structures in the electronic packaging industry.
As part of a 4-year Cosmology and Particle Astrophysics (CosPA) Research Excellence Initiative in Taiwan, AMiBA - a 19-element dual-channel 85-105 GHz interferometer array is being specifically built to search for high redshift clusters of galaxies via the Sunyaev-Zeldovich Effect (SZE). In addition, AMiBA will have full polarization capabilities, in order to probe the polarization properties of the Cosmic Microwave Background. AMiBA, to be sited on Mauna Kea in Hawaii or in Chile, will reach a sensitivity of ˜ 1 mJy or 7μK in 1 hour. The project involves extensive international scientific and technical collaborations. The construction of AMiBA is scheduled to starting operating in early 2004.
Capacitive power transfer (CPT) technology can achieve wireless power transfer based on electric field coupling. However, practical CPT systems often have cross-coupling between coupling plates of the capacitive-coupling interface, which makes accurate system analysis and compensation design tedious and complicated. In this paper, an accurate steady-state equivalent circuit model of the capacitive-coupling interface with cross-coupling is established. The model includes a parallel input capacitor linked with a series output capacitor by an ideal transformer whose turns ratio reflects the extent of cross-coupling between the plates. Effects of coupling variation on the model are analyzed in detail. The model is used for primary and secondary tuning design to achieve the maximum power transfer of a CPT system with cross-coupling. The effectiveness of the proposed model is demonstrated by both simulations and experimental results.
Aerobic exercise training has been shown to attenuate cognitive decline and reduce brain atrophy with advancing age. The extent to which resistance exercise training improves cognition and prevents brain atrophy is less known, and few studies include long-term follow-up cognitive and neuroimaging assessments. We report data from a randomized controlled trial of 155 older women, who engaged in 52 weeks of resistance training (either once- or twice-weekly) or balance-and-toning (twice-weekly). Executive functioning and memory were assessed at baseline, 1-year follow-up (i.e., immediately post-intervention), and 2-year follow-up. A subset underwent structural magnetic resonance imaging scans at those time points. At 2-year follow-up, both frequencies of resistance training promoted executive function compared to balance-and-toning (standardized difference [d]=.31–.48). Additionally, twice-weekly resistance training promoted memory (d=.45), reduced cortical white matter atrophy (d=.45), and increased peak muscle power (d=.27) at 2-year follow-up relative to balance-and-toning. These effects were independent of one another. These findings suggest resistance training may have a long-term impact on cognition and white matter volume in older women. (JINS, 2015, 21, 745–756)
The purpose of this study was to investigate the effects of maternal gestational diabetes mellitus (GDM) and breast feeding on childhood overweight and obesity in a mainland Chinese population. The incidence of and factors associated with overweight and obesity were compared between children of mothers with (n=1068) and without (n=1756) GDM. The independent roles of the associated factors were examined by multiple logistic regression analysis. The incidence of overweight was higher (16.6 v. 12.6%, P=0.002) in the GDM group, but that of obesity was not different (10.7 v. 12.0%, P=0.315). At age 1–2 and 2–5 years, no difference in overweight (11.0 v. 12.0%, P=0.917, and 15.7 v. 14.6%, P=0.693, respectively) was found, while obesity (8.0 v. 13.6%, P=0.019, and 8.4 v. 13.4%, P=0.014, respectively) was less frequent in the GDM offspring. At age 5–10 years, increased overweight (22.2 v. 12.1%, P<0.001) and obesity (15.9 v. 9.0%, P=0.001) were found in the GDM group, which was associated with maternal obesity, being born large-for-gestational age, male gender and formula feeding. After adjusting for confounding factors, GDM remained an independent determinant of offspring overweight and obesity (aOR 2.28, 95% CI 1.61–3.22), suggesting that the effects of GDM were independent of breast feeding, as well as of maternal obesity and birth size.
Three-dimensional integrated circuit packages with through-silicon vias (TSVs) provide a good solution to the integration of different chips and help achieve high performance. The signals are transmitted to different layers directly through the vias, thereby enabling the high performance of the chips. Plasma-enhanced chemical vapor-deposited SiO2, polyimide, and benzo-cyclo-butene are commonly used as the passivation layer for three-dimensional packages. In the 3D stacked chips, mismatch of the coefficient of thermal expansion between the passivation material and silicon will generate thermal/mechanical stress in the metal trace and the stress affects the behavior of electromigration. However, few studies have examined the relationship among the external mechanical stress and critical product of electromigration. In the present study, external stress is applied to the aluminum thin film by a four-point bending equipment. In order to apply higher external stress in the aluminum thin film, the fracture strength of the silicon substrate should be improved. Reduces the edge chipping of the test sample is a key factor for improving the fracture strength of the silicon substrate and a special cutting approach is employed to obtain higher silicon strength. A two-step cutting method is applied to reduce front side chipping and also a dicing before grinding approachis adopted to reduce backside chipping, the above-mentioned technology can enable more than 275MPa of external stress on the aluminum thin film and can make the critical length effect more visible. The residual stress of the aluminum thin film is at stress-free state after annealing at 300°C for 10h. The critical product is found to be reduced from 1,294A/cm to 1,281A/cm when 120MPa of mechanical tensile stress is applied. It increased to 1,315A/cm under 120MPa of mechanical compressive stress. Clearly, electromigration behavior is enhanced by tensile stress and decreased by compressive stress. In the current research, a modified equation for Blech condition is proposed with a stress-dependent effective charge number, the effective charge number increased when tensile stress was applied and decreased when compressive stress was applied.
We study the asymptotic covariance function of the sample mean and quantile, and derive a new and surprising characterization of the normal distribution: the asymptotic covariance between the sample mean and quantile is constant across all quantiles, if and only if the underlying distribution is normal. This is a powerful result and facilitates statistical inference. Utilizing this result, we develop a new omnibus test for normality based on the quantile-mean covariance process. Compared to existing normality tests, the proposed testing procedure has several important attractive features. Monte Carlo evidence shows that the proposed test possesses good finite sample properties. In addition to the formal test, we suggest a graphical procedure that is easy to implement and visualize in practice. Finally, we illustrate the use of the suggested techniques with an application to stock return datasets.