查找使用阿拉丁产品的科研文献

N-Doped Mesoporous Carbon Sheets/Hollow Carbon Spheres Composite for Supercapacitors

Lili Zhang,Lei Liu,Xiaolin Hu,Yifeng Yu,Haijun Lv,Aibing Chen

Composite carbon materials with multiple morphologies (such as spheres/sheets and spheres/tubes) that combine the merits of both structures have a wide range of applications in electrochemistry, catalysis, energy storage, and so on. Therefore, the development of an efficient and simple method for preparing carbonaceous composite materials is a research hot spot. On the basis of the inhomogeneity of 3-aminophenol/formaldehyde (3-AF) polymerization spheres, the hollow 3-AF spheres were obtained after the dissolution of the internal 3-AF oligomer. The dispersed 3-AF oligomer was reassembled with silicate oligomers on the hard template of Mg(OH)2 sheets and hollow 3-AF spheres linked by CTAB through electrostatic force. The obtained N-MCS/HCS possessed both sheet and sphere structure, with a high specific surface area and uniform mesoporous distribution. As an electrode material, N-MCS/HCS exhibited a good specific capacity (270 F g–1 at the current density of 1 A g–1) and outstanding cycling life stability (96.3% after 5000 cycles) at a current density of 5 A g–1 and could be used as a new electrode material.

Novel antibacterial fibers of amphiphilic N-halamine polymer prepared by electrospinning

Chongyi Zhu,Dan Chang,Xiao Wang,Danxia Chai,Lili Chen,Alideertu Dong,Ge Gao

As a significant role in subcategory of halogen antibacterial field, amphiphilic N -halamine polymers show a promise as potential antimicrobials having a broad spectrum of microorganisms, long-term stability, and renewal of their antibacterial properties. By controlling the process parameters, electrospinning has been well recognized as a versatile and effective method being capable of making fibers and could be easily engineered with desired pore size and porosity to enhance the antimicrobial properties. The amphiphilic N -halamine P (ADMH-MMA-HEMA) terpolymer fibers showed efficient antimicrobial properties against both Gram-positive and Gram-negative bacteria within brief contact time. The result meant that the polymer fibers of macromolecular architecture with control of structural parameters such as hydrophobicity/hydrophilicity balance achievement improved antimicrobial activities via electrospinning technique. In vitro cytotoxicity study demonstrated that the polymer was biocompatible. As a result, the integration of amphiphilic antibacterial materials and the electrospinning technique provided us a feasible method to fabricate biocompatible antimicrobial products easily with low manufacturing cost and would be applied in many promising application areas.

Electrospun CoSe@N-doped carbon nanofibers with highly capacitive Li storage

Jiandong Liu,Jiaojiao Liang,Caiyun Wang,Jianmin Ma

One-dimensional nano-structured materials have attracted attention due to its unique properties afforded such as the across-linked structures and large aspect ratios. In this work, one-dimensional CoSe@N-doped carbon nanofibers (CoSe@NC NFs) are successfully by combining the techniques of electrospinning and annealing. Selenium powder are directly dispersed in the polyacrylonitrile /N,N-Dimethylformamide (DMF) solution containing cobalt salt to form the product. The performance of these materials was investigated in Li-ion batteries after the annealing at different temperatures. The CoSe@NC nanofibers annealed at 550 °C (CoSe@NC-550) and displayed excellent storage properties, affording a high capacity of 796 mAh·g −1 at a current density of 1 A·g −1 for 100 cycles. Moreover, it is confirmed that the pseudocapacitive contribution of CoSe@NC-550 is up to 72.8% at the scan rate of 1 mV/s through the cyclic voltammetry analysis.

Analysis of N-glycans from Raphanus sativus Cultivars Using PNGase H+

Ya-Min Du,Shen-Li Zheng,Li Liu,Josef Voglmeir,Gabriel Yedid

In recent years, the carbohydrate moieties of plants have received considerable attention, as they are a potential source of cross-reactive, allergy-provoking immune responses. In addition, carbohydrate structures also play a critical role in plant metabolism. Here, we present a simple and rapid method for preparing and analyzing N-glycans from different cultivars of radish (Raphanus sativus) using an N-glycanase specific for the release of plant-derived carbohydrate structures. To achieve this, crude trichloroacetic acid precipitates of radish homogenates were treated with PNGase H+, and labeled using 2-aminobenzamide as a fluorescent tag. The labeled N-glycan samples were subsequently analyzed by ultra performance liquid chromatography (UPLC) separation and matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry for a detailed structural evaluation and to quantify relative abundancies of the radish-derived N-glycan structures. This protocol can also be used for the analysis of N-glycans from various other plant species, and may be useful for further investigation of the function and effects of N-glycans on human health.

Dual-functional imprinted magnetic nanoprobes for fluorescence detection of N-nitrosodiphenylamine

Yufeng Hu,Jie Liu,Junyu Li,Tao Chen,Minghuo Wu

Fluorescent magnetic molecularly imprinted polymers (FMMIPs) were prepared in a one-pot sol–gel polymerization process using Mn-doped ZnS quantum dots (QDs) as a fluorescent core, N-nitrosodiphenylamine (NDPhA) as a template, (3-aminopropyl) triethoxysilane (APTES) as a functional monomer, and tetraethylorthosilicate (TEOS) as a cross-linker. These FMMIPs could be used for sensing NDPhA based on their fluorescence quenching. The fluorescence intensity of the FMMIPs decreased as the concentration of NDPhA increased in the range of 0–120 μM, with a detection limit of 0.69 μM. The FMMIPs exhibited selectivity towards NDPhA over their structural analogs N-nitrosodiethylamine and sulfanilamide. Finally, the FMMIPs were successfully applied to detect NDPhA in tap water and seawater samples, and the average recoveries of NDPhA at different spiking levels ranged from 93.1% to 105.2% with relative standard deviations below 8.4%. This work provides a simple fabrication method for fluorescent magnetic MIP sensors, which can be used for the rapid determination and separation of nitrosamines from complex matrices.

VO2@SiO2/Poly(N-isopropylacrylamide) Hybrid Nanothermochromic Microgels for Smart Window

Yu Wang,Fang Zhao,Jie Wang,Ali Raza Khan,Yulin Shi,Zhang Chen,Kaiqiang Zhang,Li Li,Yanfeng Gao,Xuhong Guo

VO2/PNIPAm hybrid thermochromic material has been verified as promising to improve optical performance of smart windows. However, VO2 can be easily oxidized especially when being dispersed in the hydrogel matrix, and also the nonuniform dispersion of VO2 in a host will worsen the material’s optical performance. Herein, pure VO2(M)@SiO2 nanoparticles (NPs) were first prepared using a surfactant-free method. Then VO2(M)@SiO2/PNIPAm hybrid microgels were synthesized through suspension polymerization. The VO2(M)@SiO2 NPs in the hydrogel matrix exhibited obviously improved resistance to oxidation. Monodispersed hybrid microgel with uniformly distributed VO2(M)@SiO2 NPs (Sample I) was obtained. Meanwhile, compared with the best VO2 film reported, our composite microgel (Sample III) demonstrated a 164% increase in the solar modulating ability at a relatively high average luminous transmittance (38.4%). All these remarkable features of VO2(M)@SiO2/PNIPAm microgel synthesized in our work will help a lot in the practical application of the inorganic–organic hybrid nanothermochromic materials.

Synthesis, surface and interface tension of N-lauroyl-L-Valine sodium

Cong Luo,Bo Yang,Jian Yang,Yawen Zhou,Changyao Liu,Baocai Xu

Preparation, characterization and antibacterial properties of cellulose membrane containing N-halamine

Zhang Shengli,Kai Chengcheng,Liu Bofang,Zhang Silue,Wei Wei,Xu Xiaoling,Zhou Zuowan

Abstract Polyethylenimine (PEI), a type of water-soluble chain polymer containing a great number of primary, secondary and tertiary amine groups in the molecule, was used as an N-halamine precursor. It was grafted onto dialdehyde cellulose membrane (DCM) followed by chlorination to prepare a novel N-halamine antibacterial cellulose membrane (Cl–PEI–DCM). The appropriate conditions affecting the aldehyde content of DCM and the active chlorine (Cl + ) content of Cl–PEI–DCM were systematically studied at oxidation, grafting and chlorination stages, respectively. The structure and properties of the samples were investigated by SEM, ATR–FTIR, XRD, XPS, light transmittance measurements and tensile tests. The stability and rechargeability of the Cl–PEI–DCM were evaluated, and its antibacterial activity was tested against S. aureus and E. coli . Results showed that the Cl + content of the chlorinated samples was strongly dependent on the aldehyde content of DCM and PEI concentration. Under the optimum testing condition, the Cl + content of the Cl–PEI–DCM reached 1.30 wt%. The hydroxyl groups on the cellulose membrane were changed to aldehyde groups and the successful introduction of PEI and N–Cl bond were confirmed. The 1.30 wt% Cl–PEI–DCM exhibited high antibacterial activity against both S. aureus and E. coli , which can completely inactivate two bacterial pathogens within 5 min even after 15 days of storage. Moreover, the Cl–PEI–DCM membrane displayed good stability, rechargeability, transparency and high mechanical strength. These results demonstrated that the Cl–PEI–DCM can be considered as a visualized wound dressing material or antibacterial shoe insole. Graphical abstract

Rechargeable Antibacterial Polysulfonamide-Based N-Halamine Nanofibrous Membranes for Bioprotective Applications

Fei Wang,Mei Liu,Ruida Ding,Mingguang Liang,Liqian Huang,Jianyong Yu,Yang Si

Bioprotective materials with bactericidal activity could largely protect healthcare workers from being infected by emerging infectious diseases; however, creating such materials has turned out to be extremely challenging. Here, we fabricate a novel polysulfonamide (PSA) N-halamine electrospun nanofibrous membrane with rechargeable and rapid bactericidal properties by a Lewis acid-assisted chlorination process. The hydrogen bonds between PSA molecular chains can be weakened through Lewis acid–base complexation during chlorination, enabling more available amide groups to be chlorinated into N-halamine biocidal groups. The resulting nanofibrous membranes render intriguing features such as rechargeable chlorination capability (>4500 ppm), rapid bactericidal activity (6 log reduction of bacteria in 1 min), high particle removal efficiency (>99.8%), long-term durability, and ease of scalable production, which can be perceived as a functional layer of protective equipment that is capable of not only intercepting but also inactivating the pathogens effectively. The successful synthesis of the PSA N-halamine antibacterial nanomaterials opens new ways toward the development of bioprotective materials in a multifunctional and rechargeable form.

Measuring hydroperoxide chain-branching agents during n-pentane low-temperature oxidation

Anne Rodriguez,Olivier Herbinet,Zhandong Wang,Fei Qi,Christa Fittschen,Phillip R. Westmoreland,Frédérique Battin-Leclerc

The reactions of chain-branching agents, such as H 2 O 2 and hydroperoxides, have a decisive role in the occurrence of autoignition . The formation of these agents has been investigated in an atmospheric-pressure jet-stirred reactor during the low-temperature oxidation of n- pentane (initial fuel mole fraction of 0.01, residence time of 2   s) using three different diagnostics: time-of-flight mass spectrometry combined with tunable synchrotron photoionization, time-of-flight mass spectrometry combined with laser photoionization, and cw- cavity ring-down spectroscopy. These three diagnostics enable a combined analysis of H 2 O 2 , C 1 –C 2 , and C 5 alkylhydroperoxides, C 3 –C 5 alkenylhydroperoxides, and C 5 alkylhydroperoxides including a carbonyl function (ketohydroperoxides). Results using both types of mass spectrometry are compared for the stoichiometric mixture. Formation data are presented at equivalence ratios from 0.5 to 2 for these peroxides and of two oxygenated products, ketene and pentanediones, which are not usually analyzed during jet-stirred reactor oxidation. The formation of alkenylhydroperoxides during alkane oxidation is followed for the first time. A recently developed model of n- pentane oxidation aids discussion of the kinetics of these products and of proposed pathways for C 3 –C 5 alkenylhydroperoxides and the pentanediones.

Fluorescent poly(n-hexyl isocyanate) triblock terpolymer and its thermoreversible gels

Cui Yuheng,Kang Xin,Zhang Jie,Zhang Liqun,Yue Dongmei

Abstract Thermoreversible gels were obtained from the well-defined triblock terpolymer poly(n-hexyl isocyanate)-b-polybutadiene-b-poly(n-hexyl isocyanate) (PHIC-b-PB-b-PHIC). PHIC-b-PB-b-PHIC adopted a helical conformation and exhibited florescence in solution. The gels were prepared in both n-heptane and n-octane. The gelation concentration and temperature could be affected by various factors. Hydrogen bonding and intermolecular aggregation were the driving forces to form stable thermoreversible gels. Atomic force microscopy (AFM) showed that the microstructure of the gels consisted of aggregates of fibrous nanoribbons. Because of their thermosensitivity and fluorescence, the thermoreversible gels have potential applications in sensors and temperature-sensitive switches. Graphical Abstract

Enhanced catalytic reduction of N-nitrosodimethylamine over bimetallic Pd-Ni catalysts

Huan Chen,Ting Li,Fang Jiang,Zhe Wang

Catalytic reduction of N -nitrosodimethylamine (NDMA) was investigated over γ-Al 2 O 3 supported bimetallic Pd-Ni catalysts (3%(Pd x Ni 1−x )). NDMA could be reduced to dimethylamine over 3%(Pd 0.8 Ni 0.2 ) with a metal-loading-normalized pseudo-first-order rate constant of 836   ±   21   L   g me −1   h −1 . Characterization results showed that the reducibility of PdO (or NiO) was improved by addition of Ni (or Pd) in 3%(Pd x Ni 1−x ); Pd-Ni ensembles were formed in 3%(Pd x Ni 1−x ) and there was an electronic transfer from Pd to Ni; metal dispersion was affected by the formation of Pd-Ni ensembles and a volcano curve of metal dispersion via Pd/Ni ratio was observed. The activity profiles demonstrated that TOF had a significant positive relationship with metal dispersion of 3%(Pd x Ni 1−x ), indicating high metal dispersion favor NDMA reduction. NDMA reduction over 3%(Pd 0.8 Ni 0.2 ) catalyst could be described by Langmuir-Hinshelwood model, reflecting an adsorption controlled reduction mechanism. The reduction mechanism of NDMA over 3%(Pd 0.8 Ni 0.2 ) catalyst was proposed to be that H 2 was activated by Pd, and H spillover from Pd to Ni/NiO reduced NDMA though N-N cleavage.