A copula can characterize the complete dependence of multi-variables separately from the univariate marginals. The purpose of this paper is to provide a Bayesian nonparametric methodology to estimate a copula. We show that any bivariate copula density can be approximated by an infinite mixture of the Gaussian copula densities that are the dependence structures of the pairs with standard normal marginals. A slice sampling idea is introduced for this infinite structure that can estimate the number of occupied clusters in a sampler. The estimation procedure is proposed by the Gibbs sampling algorithm. Simulation and real data application illustrate the rational of the proposed approach.
Ulcerative colitis (UC) is an incurable chronic inflammation of the enteric tract. The aim of this study was to investigate the protective effects of arabinogalactan from Lycium barbarum on DSS-induced...
Near-infrared (NIR) light is an ideal source for initiating polymerization because of the lower energy of NIR photons and considering that NIR light usually has deeper penetration depth in materials than UV light. Recently, lanthanide-doped upconverting nanoparticles (UCNPs) were used for NIR photopolymerization. UCNPs convert NIR light to UV or visible light, which can subsequently be absorbed by photosensitizers or photo-initiators. Subsequently, the excited photosensitizers/photoinitiators trigger polymerization. This process is referred to UCNP-assisted photopolymerization. Herein, recent progress in UCNP-assisted photopolymerization is introduced, applications of materials prepared via this type of reaction are highlighted, and the associated challenges are discussed.[a] Prof.
A flexible symmetric thread‐like supercapacitor (TSC) with high operating voltage window and good electrochemical performance is manufactured, that fulfills the requirements of wearable electronics. First, iron oxide (Fe2O3) nanosheets are directly grown in situ on the surface of stainless steel yarn (SSY) by an acid corrosion and self‐oxidation process, and then a polypyrrole (PPy) coating is covered on the surface of Fe2O3 nanosheets via chemical oxide method to obtain the thread‐like PPy@Fe2O3@SSY composite electrode. The electrode achieves a wide potential range of −1.0–0.8 V (versus Ag/AgCl) and a high areal specific capacitance of 667.8 mF cm−2 with outstanding galvanostatic charge/discharge cycling stability of 87.5% capacitance retention after 10 000 cycles in 1 m lithium sulfate (Li2SO4) aqueous solution. The symmetric TSC based on the PPy@Fe2O3@SSY electrode and carboxymethyl cellulose sodium salt/Li2SO4 gel electrolyte exhibits a wide operating voltage window of 1.8 V, and its maximum energy density can reach 39.3 μWh cm−2. Additionally, the TSC demonstrates excellent electrochemical performance under various bending states and a bending cycling test. The preparation method and raw materials are low‐cost and scalable, and the overall performance of the TSC is excellent, which makes this device a promising energy storage device for wearable electronics.
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