埋入水中旋转薄壳谐耦振分析的传递矩阵法

基于一般线弹性薄壳和势流理论,导出了旋转壳状态向量的一阶常微分矩阵方程和水动压力表达式,再借助齐次扩容技术和精细积分法,应用推广的传递矩阵法对埋入水中旋转薄壳的流固耦振进行了数值求解,并研究了一些因素对精度的影响.算例表明传递矩阵法和有限元方法相比不仅精度良好,而且有较高的计算效率.     

Bifunctional imidodiphosphoric acid‐catalyzed controlled/living ring‐opening polymerization of trimethylene carbonate resulting block, α,ω‐dihydroxy telechelic,and star‐shaped polycarbonates

The ring‐opening polymerization (ROP) of trimethylene carbonate (TMC) using imidodiphosphoric acid (IDPA) as the organocatalyst and benzyl alcohol (BnOH) as the initiator has been investigated. The polymerization proceeded without decarboxylation to afford poly(trimethylene carbonate) (PTMiC) with controlled molecular weight and narrow polydispersity. ¹H NMR, SEC, and MALDI‐TOF MS measurements of the obtained PTMC clearly indicated the quantitative incorporation of the initiator at the chain end. The controlled/living nature for the IDPA‐catalyzed ROP of TMC was confirmed by the kinetic and chain extension experiments. A bifunctional activation mechanism was proposed for IDPA catalysis based on NMR and FTIR studies. Additionally, 1,3‐propanediol, 1,1,1‐trimethylolpropane, and pentaerythritol were used as di‐ol, tri‐, and tetra‐ol initiators, producing the telechelic or star‐shaped polycarbonates with narrow polydispersity indices. The well‐defined diblock copolymers, poly(trimethylene carbonate)‐block‐poly(δ‐valerolactone) and poly(trimethylene carbonate)‐block‐poly(ε‐caprolactone), have been successfully synthesized by using the IDPA catalysis system. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1009–1019     

N‐heterocyclic carbenes as organocatalysts in controlled/living ring‐opening polymerization of O‐carboxyanhydrides derived from l‐lactic acid and l‐mandelic acid

An organocatalytic approach to controlled/living ring‐opening polymerizations (ROPs) of O‐carboxyanhydrides (OCAs) using N‐heterocyclic carbenes (NHCs) as nucleophilic catalysts has been investigated. NHCs with different structures were used in order to compare the catalytic performances in the ROP of OCA of l ‐lactic acid. ¹H NMR, SEC, and MALDI‐TOF MS measurements of the products clearly indicated a controlled/living manner of the polymerization. The controlled/living nature was further confirmed by kinetic and chain extension experiments. Additionally, polylol initiators were used to produce α,ω‐dihydroxy telechelic, 3‐, and 4‐armed star‐shaped polymers. Moreover, star‐shaped diblock copolymer, bearing methyl and phenyl side groups, has been successfully synthesized with OCA/NHC system. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 . 52, 2306–2315     

A general low-temperature route for large-scale fabrication of highly oriented ZnO nanorod/nanotube arrays

Large-scale arrays of highly oriented hexagonal ZnO nanorods and nanotubes were fabricated on arbitrary ZnO-film-coated substrates using a low-temperature chemical-liquid-phase deposition method. The obtained nanoproducts were characterized, and the growth mechanism is proposed.     

Synthesis and characterization of multifunctional propenyl‐endcapped aromatic co‐monomers and their use as bismaleimide modifiers

A series of novel modifiers for bismaleimide, bearing propenyl and phenoxy functional groups has been synthesized. Structural information of the monomers was obtained through Fourier transform infrared spectroscopy (FT‐IR), nuclear magnetic resonance (NMR) spectroscopy and elemental analysis. Polymerization characteristics demonstrate that all four systems prepared have a cure temperature below 210°C. This remarkably lower cure temperature compared to that of other polymerization reactions involving diallyl bisphenol A and bismaleimide (DBMI) originates from propenyl groups being present in the structures as well as their larger free volume. The rheological behaviors leading to low melt viscosities and the wide process window of the prepolymer are particularly suitable characteristics for the production of performance resin‐based composite materials via resin transfer molding processes. The dynamic mechanical analysis of the materials reveals glass transition temperatures in a range between 260°C and 293°C. Thermal stabilities show a 5% weight loss at temperatures ranging from 363°C to 428°C with the production of char ranging from 38.5% to 57.6% at 800°C under nitrogen. The latter is a clear indication for the excellent thermal stabilities featured by the cured resins. Furthermore, the dielectric properties exhibit a significantly lower dielectric constant and dissipation factors of the propenyl‐modified cured systems compared to those of DBMI resins at 10 GHz. Copyright © 2015 John Wiley & Sons, Ltd.     

A Membrane Tension-Responsive Mechanosensitive DNA Nanomachine

Membrane curvature reflects physical forces operating on the lipid membrane, which plays important roles in cellular processes. Here, we design a mechanosensitive DNA (MSD) nanomachine that mimics natural mechanosensitive PIEZO channels to convert the membrane tension changes of lipid vesicles with different sizes into fluorescence signals in real time. The MSD nanomachine consists of an archetypical six-helix-bundle DNA nanopore, cholesterol-based membrane anchors, and a solvatochromic fluorophore, spiropyran (SP). We find that the DNA nanopore effectively amplifies subtle variations of the membrane tension, which effectively induces the isomerization of weakly emissive SP into highly emissive merocyanine isomers for visualizing membrane tension changes. By measuring the membrane tension via the fluorescence of MSD nanomachine, we establish the correlation between the membrane tension and the curvature that follows the Young-Laplace equation. This DNA nanotechnology-enabled strategy opens new routes to studying membrane mechanics in physiological and pathological settings.     

Construction of Low-Coordination Cu−C2 Single-Atoms Electrocatalyst Facilitating the Efficient Electrochemical CO2 Reduction to Methane

Constructing Cu single-atoms (SAs) catalysts is considered as one of the most effective strategies to enhance the performance of electrochemical reduction of CO₂ (e-CO₂RR) towards CH₄, however there are challenges with activity, selectivity, and a cumbersome fabrication process. Herein, by virtue of the meta-position structure of alkynyl in 1,3,5-triethynylbenzene and the interaction between Cu and −C≡C−, a Cu SAs electrocatalyst (Cu−SAs/HGDY), containing low-coordination Cu−C₂ active sites, was synthesized through a simple and efficient one-step method. Notably, this represents the first achievement of preparing Cu SAs catalysts with Cu−C₂ coordination structure, which exhibited high CO₂-to-CH₄ selectivity (72.1 %) with a high CH₄ partial current density of 230.7 mA cm⁻², and a turnover frequency as high as 2756 h⁻¹, dramatically outperforming currently reported catalysts. Comprehensive experiments and calculations verified the low-coordination Cu−C₂ structure not only endowed the Cu SAs center more positive electricity but also promoted the formation of H•, which contributed to the outstanding e-CO₂RR to CH₄ electrocatalytic performance of Cu−SAs/HGDY. Our work provides a novel H⋅-transferring mechanism for e-CO₂RR to CH₄ and offers a protocol for the preparation of two-coordinated Cu SAs catalysts.     

Aptamer based fluorescent probe for serum HER2-ECD detection: The clinical utility in breast cancer

HB5 aptamer-based probe has been developed for serum HER2-ECD test in auxiliary clinical diagnosis and treatment for HER2-positive breast cancer patients.     

Biomarker-targeted fluorescent probes for breast cancer imaging

This review summarized fluorescent probes for breast cancer imaging according to different biomarkers probes recognized.