Highly rectified ion transport through 2D WSe2/MoS2 bi-layered membranes

Through a two-step vacuum-filtration process, WSe₂ and MoS₂ nanosheets were sequentially deposited onto a polymeric nanoporous support, forming WSe₂/MoS₂ bi-layered heterostructure. Highly rectified ion transport phenomenon is observed through the heterogeneous 2D layered membranes.     

蒙特卡罗计算中颗粒型燃料的随机分布模型比较

高温气冷堆是新一代反应堆系统的热门候选堆型，已经受到国际上越来越多的关注。为设计和分析这种堆型，因其特有的包覆颗粒燃料引入了双重非均匀性，需要应用随机分布模型。对粗网格模型、细网格随机(FLS)模型、随机顺序添加(RSA)模型、子网格随机(Sub-FLS)模型和Metropolis模型等进行了研究，通过计算分析比较给出了各种模型的优缺点。结果表明:子网格随机模型和连续的RSA模型非常接近参考值，但是连续RSA模型的建模时间随着燃料体积份额的增加连续快速上升。 Key words: coated particle fuels; stochastic transport model; Monte Carlo; random distribution     

Studies on the Electronic Transport Properties of some New Chelate Compounds Containing Siloxane

The temperature dependence of the electrical conductivity and the Seebeck coefficient of some new complex polymeric structures containing metal chelate sequences alternating with silane units were studied. The measurements were performed using thin films deposited from solution. The investigated polymers have interesting semiconducting characteristics. The correlations between these characteristics and the molecular structure of the respective polymers are discussed.     

Synthesis and characterization of phenol‐based biaryl proton conducting polymers

Biaryl hydroxy polymers with orthogonal disposition of proton transporting ? OH moieties have been synthesized via conventional free radical polymerization. The polymers are characterized for their thermal stability and proton conductivity, and the results are compared with the corresponding styrenic hydroxy polymers. The orthogonal disposition of ? OH moieties in biaryl polymers does result in lower E_a for proton transport. However, the lower E_a values in biaryl polymers did not translate into a net increase in proton conductivity. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Benzodifuran‐containing well‐defined π‐conjugated polymers for photovoltaic cells

Two well‐defined alternating π‐conjugated polymers containing a soluble electroactive benzo[1,2‐b:4,5‐b′]difuran (BDF) chromophore, poly(BDF‐(9‐phenylcarbazole)) (PBDFC), and poly(BDF‐benzothiadiazole) (PBDFBTD) were synthesized via Sonogashira copolymerizations. Their optical, electrochemical, and field‐effect charge transport properties were characterized and compared with those of the corresponding homopolymer PBDF and random copolymers of the same overall composition. All these polymers cover broad optical absorption ranges from 250 to 750 nm with narrow optical band gaps of 1.78–2.35 eV. Both PBDF and PBDFBTD show ambipolar redox properties with HOMO levels of ?5.38 and ?5.09 eV, respectively. The field‐effect mobility of holes varies from 2.9 × 10^?8 cm² V^?1 s^?1 in PBDF to 1.0 × 10^?5 cm² V^?1 s^?1 in PBDFBTD. Bulk heterojunction solar cell devices were fabricated using the polymers as the electron donor and [6,6]‐phenyl‐C₆₁‐butyric acid methyl ester as the electron acceptor, leading to power conversion efficiencies of 0.24–0.57% under air mass 1.5 illumination (100 mW cm^?2). These results indicate that their band gaps, molecular electronic energy levels, charge mobilities, and molecular weights are readily tuned by copolymerizing the BDF core with different π‐conjugated units. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Optimal Transport for the System of Isentropic Euler Equations

We introduce a new variational time discretization for the system of isentropic Euler equations. In each timestep the internal energy is reduced as much as possible, subject to a constraint imposed by a new cost functional that measures the deviation of particles from their characteristic paths.     

Electronic transport study of PbSe pellets prepared from self-assembled 2D-PbSe nanostructures

This work presents a study of the electronic transport properties of PbSe pellets fabricated starting of PbSe nanostructures that exhibited a flake-like 2D morphology, which were synthesized by the co-precipitation method. Seebeck coefficient measurements revealed that the PbSe sample displays n-type conductivity, a maximum Seebeck coefficient of −512.6 μV/K around 380 K, and that the carriers scattering is dominated by acoustic and optical phonons. The Fermi level dependence on the temperature and the band gap energy are also reported. Interestingly, size-dependent confinement effects due probably to the reminiscent PbSe 2D character could be evidenced.     

Poly(2-hydroxyethyl acrylate) hydrogels containing hyper-branched poly(amidoamine) for sustained drug release

Hydrogels containing hyper-branched poly(amidoamine) (hb-PAMAM) microenvironments were suggested for the sustained release of ionizable drugs. For this purpose, a series of poly(2-hydroxyethyl acrylate) (PHEA) hydrogels containing hb-PAMAM (PHEA-hb-PAMAM) were prepared by copolymerization of 2-hydroxyethyl acrylate with acryl-terminated hb-PAMAM. The hb-PAMAM was synthesized by the Michael addition reaction of triacryloylhexahydro-1,3,5-triazine (TT) and piperzaine (PZ). By using nonionic Tegafur and ionizable salicylic acid (SA) as model drugs, the release mechanisms of drugs from PHEA-hb-PAMAM hydrogels were investigated. Compared with the release kinetic of Tegafur, the release rate of SA from the hydrogels was evidently slowed down. Moreover, the release rate of SA can be modulated by the addition of salt. This can be attributed to the ionic interaction of SA with hb-PAMAM microenvironments. By analyzing the release kinetics of SA from the hydrogels, it was found that the release of SA followed non-Fickian diffusion.