Search

In this paper, an evaluation model is presented to assess the utility of probabilistic models in terms of their capacity to successfully oversample policy relevant population subgroups that are subject to transitions. Examples of these applications are drawn from the Medical Expenditure Panel Survey (MEPS). Given the high concentration of health care expenditures in a given year among a relatively small percentage of the population, a prediction model that can accurately identify the persistence of high levels of expenditures is an important analytical tool. This type of modeling effort also enhances the ability to discern the causes of high health care expenses and the characteristics of the individuals who incur them. This feature also applies to prediction models that can accurately identify those individuals with persistently low or average levels of expenditures. The models that are presented have particular relevance as statistical tools to facilitate efficient sampling strategies that permit the selection of an over-sample of individuals likely to incur high levels of medical expenditures in the future. Keywords: Medical expenditure predictions, MEPS

The Medical Expenditure Panel Survey Household Component (MEPS-HC) is designed to provide nationally representative annual estimates of health care use, expenditures, sources of payment, and insurance coverage for the US civilian noninstitutionalized population. The expenditure data from MEPS have been shown to exhibit a marked positive skewness, with a few high expenditure respondents and many low or zero expenditure respondents. As a consequence of this departure from the normal distribution, the frequency with which a conventional confidence interval for a MEPS expenditure estimate will not capture the true population parameter may be higher than the probability stated for the confidence interval. Based on repeated sample simulations using data from the 1996 to 2001 MEPS-HC, this paper evaluates and compares the actual probability achieved for confidence intervals derived from expenditure data by types of expenditure and varying sample sizes. The results are also compared to estimated confidence probabilities obtained from repeated sample simulations for other types of variables that do not exhibit as marked a positive skewness as health care expenditures. Keywords: Skewness of medical expenditures, MEPS

In recent years, high-entropy alloys (HEAs) that contain fine grains of intermetallic compounds (IMCs) have gained increasing attention as they have been shown to exhibit both high mechanical strength and strong corrosion resistance. One such class of HEAs is that of CuFeTiZrNi alloys. In this study, we have investigated the effect of increasing Ni content on the microstructure, hardness, and corrosion resistance of the CuFeTiZrNix alloys (where x = 0.1, 0.3, 0.5, 0.8, 1.0 in a molar ratio). The alloys used in this study were prepared in an arc melting furnace and then annealed at 900 °C. First-principles calculations of the bulk modulus were also performed for each alloy. The results revealed that increasing the Ni content had several effects. Firstly, the microstructure of the CuFeTiZrNix alloys changed from B2_BCC and Laves_C14 in the CuFeTiZrNi0.1 and CuFeTiZrNi0.3 alloys to FCC, B2_BCC, and Laves_C14 in the CuFeTiZrNi0.5 alloys; and to FCC, B2_BCC, Cu51Zr14, and Laves_C14 in the CuFeTiZrNi0.8 and CuFeTiZrNi1.0 alloys. Secondly, IMCs arising from a combination of the refractory elements (Ti and Zr) and atomic size differences were found in the interdendritic region. Thirdly, as the Ni content in the CuFeTiZrNix alloys increased, the hardness decreased, but the corrosion resistance increased. [ABSTRACT FROM AUTHOR]

The dimension is a leading parameter in customization of unique optoelectronic properties of halide perovskite, while it is still challenging to achieve dimension control beyond the well‐developed composition regulation‐based strategy considering their intrinsic feature of ionic crystal. In this paper, ligands‐directed confinement effect is emphasized in rendering the reduced‐dimensional engineering of halide perovskite, and quasi‐2D (OAm)2CsPb2Br7 (n = 2) nanosheets are obtained by introducing a large amount of metal ions. As a representation, with Mg2+ participation, the initial adsorption of organic ligands (i.e., OA and OAm) to inorganic components (i.e., [PbBr6]4−) is promoted, conferring a ligands‐directed surface reconstruction to form the lamellar structure composed of alternate organic and inorganic layers. Namely, the inorganic–organic lamellar ensemble will play as a soft template, which effectively restricts the growth of [PbBr6]4− in the c‐axis direction even after the Cs‐OA injection, thus producing the anisotropic layered perovskite of (OAm)2CsPb2Br7 from CsPbBr3 scenario. Notably, such reduced‐dimensional engineering enables a remarkable luminescence tailoring, of which the deep blue emission centered at 439 nm is achieved. In addition, benefiting from such universal strategy, the luminescence is also dependent on the species of introduced metal ions (e.g., Ca2+, Co2+, Sr2+, and Mn2+). [ABSTRACT FROM AUTHOR]

Although light‐emitting devices (LEDs) based on metal halide perovskite nanocrystals (PNCs) developed rapidly in recent years, the luminance of pure red LEDs with the Rec. 2020 standard Commission Internationale de l'Eclairage 1931 color coordinates of (0.708, 0.292) cannot meet the requirement of outdoor display. Herein, a facile in situ modification strategy is proposed to prepare the efficiently luminescent CsPb(Br/I)3 PNCs, where metal bromides are used to create a halide‐rich environment and inhibit the formation of nonradiative surface defects. Synchronously, appropriately increased surface ligands improved the effective exciton confinement. Hence, the modified CsPb(Br/I)3 PNCs exhibited a high photoluminescence quantum yield of 92.0%. Additionally, the electrical conductivity is improved due to the increased hole mobility, and the Auger process is inhibited caused by balanced carrier mobilities. Consequently, LEDs based on the modified CsPb(Br/I)3 PNCs exhibited a maximum luminance of 11233 cd m−2 with the pure red color coordinate (0.704, 0.292) and a peak external quantum efficiency value of 13.2%. Furthermore, the luminance reached 5198 cd m−2 under the driving voltage of 4.4 V. This is the first study to realize a pure red PNC LED with high luminance under low bias, which can meet the requirement of outdoor display. [ABSTRACT FROM AUTHOR]

Highlights: A reversible Zn2+ insertion in anatase TiO2 nanocrystals is reported for the first time. This is the first report regarding TiO2 for zinc-anode-based electrochromic devices, which will subsequently broaden its applications to zinc-ion electrochemical cells. A prototype device based on the TiO2 nanocrystals delivers a high optical modulation, fast response times, and robust electrochemical stability.Zinc-anode-based electrochromic devices (ZECDs) are emerging as the next-generation energy-efficient transparent electronics. We report anatase W-doped TiO2 nanocrystals (NCs) as a Zn2+ active electrochromic material. It demonstrates that the W doping in TiO2 highly reduces the Zn2+ intercalation energy, thus triggering the electrochromism. The prototype ZECDs based on W-doped TiO2 NCs deliver a high optical modulation (66% at 550 nm), fast spectral response times (9/2.7 s at 550 nm for coloration/bleaching), and good electrochemical stability (8.2% optical modulation loss after 1000 cycles). [ABSTRACT FROM AUTHOR]