查找使用阿拉丁产品的科研文献

Bioactive Constituents of F. esculentum Bee Pollen and Quantitative Analysis of Samples Collected from Seven Areas by HPLC

Feng Li,Sen Guo,Shanshan Zhang,Sainan Peng,Wei Cao,Chi-Tang Ho,Naisheng Bai

Bee pollen contains all the essential amino acids needed by humans. China is the largest producer of bee pollen in the world. In the present study, we identified 11 fatty acids inF. esculentumbee pollen oil by GC-MS analysis, and 16 compounds were isolated fromF. esculentumbee pollen by column chromatography and identified. A high-performance liquid chromatography-diode array detector (HPLC-DAD) method was established for the quality control ofF. esculentumbee pollen. A validated HPLC-DAD method was successfully applied to the simultaneous characterization and quantification of nine main constituents in seven samples collected from seven different areas in China. The results showed that all standard calibration curves exhibited good linearity (R2> 0.999) in HPLC-DAD analysis with excellent precision, repeatability and stability. The total amount in the samples from the seven regions ranged from 23.50 to 46.05 mg/g. In addition, seven compounds were studied for their bioactivity using enzymic methods, whereby kaempferol (3) showed high α-glucosidase inhibitory activity (IC50: 80.35 μg/mL), ergosterol peroxide (8) showed high tyrosinase inhibitory activity (IC50: 202.37 μg/mL), and luteolin (1) had strong acetylcholinesterase inhibitory activity (IC50: 476.25 μg/mL). All results indicated thatF. esculentumbee pollen could be a nutritious health food.Keywords:bee pollen;enzyme inhibitory activity;HPLC-DAD;GC-MS;quality analysis

High-performance piezo-damping materials based on CNTs/BaTiO3/F-PAEK-b-PDMS under high temperature steam conditions

Xiang Yu,Yu Zhang,Lan Jin,Jingyu Chen,Zhenhua Jiang,Yunhe Zhang

Polymeric piezo-damping composites with robust piezo-damping performance under high temperature steam conditions are highly desirable. In this study, we demonstrate a novel piezo-damping material, consisting of fluorinated (polyaryletherketone)-(polydimethylsiloxane) block copolymers (F-PAEK-b-PDMS) as matrix, multi-walled carbon nanotubes (CNTs) as conductive filler, and barium titanate (BT) as piezoelectric phase. Taking the advantages of hydrophobic property of PDMS and good thermal stability of F-PAEK, piezo-damping materials exhibit good stability under high temperature steam conditions. Furthermore, for the incompatibility between F-PAEK and PDMS, microphase separation appears, which can greatly increase the friction between molecules for better damping capability. Good damping performances that loss factor > 0.3 over a broad temperature range of 55–115 °C (≈60 °C) can be achieved. Those outstanding performances can effectively broaden the practical application of piezo-damping composites under harsh conditions.

A synergistic anti-corrosion system based on durable superhydrophobic F-SiO2/epoxy coatings and self-powered cathodic protection

Xiukun Liu,Xu Xu,Fangjia Zhang,Xiangchao Ge,Haifeng Ji,Yuqi Li,Shaorong Lu,Zhen Wen

A sustainable, reliable and self-powered anti-corrosion method for metallic structures is key to improving the operation stability and service life of equipment. In this work, a series of durable superhydrophobic fluorinated silica (F-SiO2)/epoxy resin (FE) coatings with good corrosion resistance were prepared via a simple spraying method, which were further used to fabricate a FE based triboelectric nanogenerator (FE-TENG). A synergistic anti-corrosion system for self-powered cathodic protection constructed using the superhydrophobic FE coating and a water wave-driven FE-TENG was then proposed. In a 3.5 wt% NaCl solution, the corrosion potential (Ecorr) of an aluminum (Al) sheet protected by the FE-TENG self-powered cathodic protection was slightly decreased by 80 mV. However, when the Al sheet was coated with a FE superhydrophobic coating, the Ecorr was significantly reduced by 460 mV under FE-TENG protection. Notably, the Ecorr of 304 stainless steel protected by the synergistic anti-corrosion system was dramatically decreased by ∼745 mV. Furthermore, an application in marine corrosion protection was demonstrated by using a float-like spherical FE-TENG. This work demonstrates a cost-effective and large-scale strategy for preparing a superhydrophobic FE coating, using which a self-powered synergistic anti-corrosion system is built for effectively protecting metals from corrosion.

B, F Co-doping flexible carbon nanofibers as a fast and stable anode for potassium-ion hybrid capacitor

Zuocheng Luo,Qingfeng Zhang,Wei Xie,Tong Yuan,Qisheng Zang,Ning Wang,Hanxiao Fan,Shuhong Xie,Xiaoping Ouyang

Potassium ion hybrid capacitors (PIHCs) have attracted widespread attention as combining the advantages of potassium ion batteries (PIBs) with supercapacitors . However, the sluggish kinetics caused by the large radius of K + hinder the practical application of PIHCs. Herein, we synthesized a boron and fluorine co-doping interlaced network porous carbon nanofibers (BF-PCNFs), which was used as the freestanding anode of PIHCs the freestanding anode of PIHCs to alleviate large volume expansion and increase conductivity. Benefiting from the B, F co-doping and porous interlace nanostructure of BF-PCNFs, the anode shows 185 mA h g −1 under a load of 12.6 mg cm −2 , a reversible capacity of 176 mA h g −1 at 1000 mA g −1 after 6000 cycles, and the capacity retention from 100 mA g −1 to 5000 mA g −1 is 62%. Furthermore, the PIHCs based on BF-PCNFs as anode and activated carbon as cathode exhibit an energy density of 87 Wh kg −1 and a power density of 393 W kg −1 . The capacity retention is as high as 78% over 4000 cycles. Considering the exceptional rate performance, long cyclability and high-mass-loading, our work may supply a new strategy for designing novel energy storage devices with outstanding performance.

Ni and F co-modification to enhance the electrochemical properties of Li4Ti5O12 anode materials for lithium-ion batteries

Zhai Huanhuan,Shuai Yi,Wang Yu,Chen Kanghua

As a negative electrode material, the main drawbacks of Li 4 Ti 5 O 12 (LTO) are its low electric conductivity and poor Li-ion diffusion coefficient. Fortunately, elements modification to address these problems is an effective method. Herein, we firstly report Ni and F co-modified LTO material which is synthesized via a solid-state reaction. Powder X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy were conducted to investigate the structure and morphology. Afterwards, we surprisingly find that Ni and F co-modification can reduce the overall charge transfer resistance of LTO for part of Ti 4+ converts into Ti 3+ and Ni 2+ ions supply the charge carriers. When test in battery, a superior discharge capacity of 236.1 mAh g −1 at 0.036 A g −1 is obtained, much higher than that of pristine LTO (196.9 mAh g −1 ). Furthermore, it still retains a discharge capacity of 174.6 mAh g −1 after 200 cycles at 0.18 A g −1 and exhibits an excellent rate performance.

Relation of thickness and luminescence in F-modified silicate based remote phosphor coating for white light emitting diodes

Li Rui,Wang Yan-ze,Mao Zhi-yong,Wang Da-Jian

A remote phosphor coating by using Sr 3 (Al,Si)(O, F) 5 :Ce 3+ (SASF:Ce 3+ ) on glass substrate was prepared by a simple and convenient screen printing method. The crystalline phase and the distribution of SASF:Ce 3+ crystals in coating were investigated by XRD and SEM, respectively. The scattering light and absorption light properties of remote phosphor coating with different thicknesses were discussed through Lambert–Beer’s law. The relationship between luminous efficiency and absorption coefficient was demonstrated. White light emitting diode prototype fabricated with blue chip and the prepared patterned SASF:Ce 3+ remote phosphor in this work showed excellent performances, opening a cost-effective process to generate planar white light.

From Pb(H2C3N3O3)(OH) to Pb(H2C3N3O3)F: Homovalent Anion Substitution-Induced Band Gap Enlargement and Birefringence Enhancement

Yan Chen,Chunli Hu,Zhi Fang,Yilin Li,Jianggao Mao

Birefringent materials capable of modulating the polarization of light have attracted intensive studies because of their wide utilization in optical communication and the laser industry. Herein, two new lead(II)-based cyanurates, namely, Pb(H2C3N3O3)X (X = OH, F), were synthesized by hydrothermal methods, and the first halogen-containing metal cyanurate Pb(H2C3N3O3)F was successfully obtained by the rational substitution of a homovalent anion. Pb(H2C3N3O3)X (X = OH, F) belong to space group P1̅, and their structures display a neutral [Pb(H2C3N3O3)X] (X = OH, F) layer. The Pb2+ ions in Pb(H2C3N3O3)(OH) are interconnected by hydroxyl groups and oxygen atoms of cyanurate anions into a 1D [PbO(OH)]− chain, whereas the Pb2+ ions in Pb(H2C3N3O3)F are interconnected by F– anions and oxygen atoms of cyanurate anions into a 2D [PbOF]− layer. The π–π interactions between adjacent hydroisocyanurate rings and the hydrogen bonds between neighboring neutral layers provide additional stability to the structures. Luminescent studies show that Pb(H2C3N3O3)(OH) and Pb(H2C3N3O3)F emit yellow-green and blue light, respectively. Theoretical calculations unveiled their birefringences of 0.079 and 0.203@1064 nm and their band gaps of 3.96 and 4.96 eV, respectively, for OH– and F– containing materials. Obviously, the substitution of OH– by F– with the largest electronegativity can simultaneously improve both the birefringence and band gap.

Effects of Vitamin B12 on the Reductive Transformation of PFOS and F-53B by Nanoscale Zero-Valent Zinc

Perfluorooctane sulfonate (PFOS) and 6:2 chlorinated polyfluoroalkyl ether sulfonate (F-53B) are persistent per- and polyfluoroalkyl substances of concern in aquatic environments. This study compared their anaerobic reductive transformation by nanoscale zero-valent zinc (nZn0), with and without vitamin B12 (VB12). Solutions containing 1 mg/L PFOS or F-53B were treated with nZn0(278 mg/L) and, where indicated, 0.05 mmol/L VB12 (67.8 mg/L) at pH 8.5 and 30 °C for 20 days. After correction for losses observed in reagent-free blanks, PFOS loss was negligible with nZn0alone but reached approximately 34% with nZn0+ VB12, and the corresponding defluorination rate was 33.9%. In contrast, F-53B showed approximately 85% blank-corrected loss by day 6 with either nZn0alone or nZn0+ VB12, while defluorination rates reached 38.0% and 30.7%, respectively, indicating no enhancing benefit of VB12 for F-53B under the studied conditions. Nominal-mass LC-MS/MS features consistent with partially defluorinated and hydrogen-substituted products were observed, and tentative transformation pathways were proposed. These results demonstrated compound-specific effects of VB12 and emphasized the distinction among loss, transformation and defluorination when evaluating PFAS destruction.

TiH2 content-tuning strategy for synergistic enhancement of safety and combustion performance in HMX/TiH2/F composite microspheres

Penglin Kang,Jinbo Guo,Xiaojuan Fu,Yuan Lai,Xiangru Li,Leixin Hou,Wenjie Liu,Xiaodong Li

To achieve high-energy composites with both high energy density and enhanced safety, TiH 2 /HMX/F energetic microspheres were fabricated using a coaxial flow-focusing microdroplet technique. The effects of varying TiH 2 contents on the chemical structure, thermal decomposition, mechanical sensitivity, combustion characteristics, and combustion products were systematically examined. The results show that the microspheres exhibit a dense structure, narrow particle-size distribution, and uniform component dispersion, while retaining the crystalline form and chemical structure of the raw HMX and TiH 2 . With increasing TiH 2 content (5, 10, 15, and 20 wt%), the apparent activation energy rises by 21.58, 66.35, 98.33, and 146.09 kJ mol −1 , respectively, compared with the H/F sample, indicating reduced reactivity but significantly improved thermal stability. At 10 wt% TiH 2 , the critical impact energy and friction force increase by 4.0 J and 164.0 N, respectively, demonstrating enhanced mechanical safety. Combustion tests reveal that TiH 2 not only strengthens combustion intensity but also prolongs the reaction duration. When the TiH 2 content exceeds 5 wt%, oxidation becomes more complete, with TiO 2 and TiN identified as the main products. In addition, the combustion mechanism was clarified, highlighting the role of TiH 2 in promoting high-temperature oxidation and improving combustion completeness. These findings provide both theoretical insights and process guidance for optimizing the performance and safety of high-energy composite materials.

Synergistic Removal of Bromate and Ibuprofen by Graphene Oxide and TiO2 Heterostructure Doped with F: Performance and Mechanism

Yan Zhang,Jiarong Li,Hongyuan Liu

The batch experiments of photocatalytic oxidation-reduction of bromate and ibuprofen (IBP) by graphene oxide (GO) and TiO2 heterostructure doped with F (FGT) particles were conducted. The performance and mechanism of synergistic removal of bromate and IBP by FGT were discussed. The results show that a demonstrable synergistic effect and excellent removal rate of bromate and IBP by FGT were exhibited. When pH is 5.2 and the dosage of FGT is 0.1 g/L, the reaction rate constants of bromate and IBP increased from 0.0584 min-1 and 0.4188 min-1 to 0.1353 min-1 and 0.4504 min-1, respectively, compared with the degradation of bromate or IBP alone. The reaction of photocatalytic synergistic degradation is appropriately fitted through Langmuir-Hinshelwood first-order kinetics. The mechanism of synergistic removal of bromate and IBP by FGT was discussed. And electrons (e-), hydroxyl radical (⋅OH), and superoxide radical (⋅O2-) are the main active species. The electrons play a main role in the bromate reduction, and bromine is the only reduction product, while the oxidation of IBP is the result of ⋅OH and ⋅O2-, and ⋅OH plays a key role. The recombination of electrons and holes is inhibited by simultaneous consumption of bromate and IBP, which makes full use of the redox properties of FGT and plays a synergistic role in the removal of pollutants. The results indicate that photocatalytic oxidation-reduction by FGT is a promising, efficient, and environmental-friendly method for synchronous removal of combined pollution in water.

Miniemulsion polymerization-formulated poly(fluorene-alt-6-(2-ethylhexyl)-[1,2,5]thiadiazole[3,4-f]benzotriazole) for cancer cell imaging

Zhiguo He,Xuejiao Han,Hui Xie,Zifeng Yan,Bing Guo,Youwei Yao

Near-infrared (NIR) conjugated polymer nanoparticles (CPNPs) possesses advantages for bioimaging because of their merits in low autofluorescence interference, good biocompatibility, large light extinction coefficient, improved photostability, and facile functionalization capability. Different from conventional post-polymerization methods for fabricating NIR CPNPs, like nanoprecipitation, emulsion and solvent evaporation/miniemulsion, and self-assembly, herein, an efficient one-pot strategy by in-situ miniemulsion polymerization is demonstrated to synthesize CPNPs for NIR fluorescence imaging of cancer cells. Via adjusting the donor-acceptor strength , the new CP, poly(fluorene- alt -6-(2-ethylhexyl)-[1,2,5]thiadiazole[3,4- f ]benzotriazole) ( PFTA ), show absorption and emission maximum at 648 nm and 730 nm, respectively, which is much more red-shifted than its counterpart, poly(fluorene- alt -benzo-2,1,3-thiadiazole) ( PFBT ). DFT calculation demonstrates that the repeating unit of PFTA has a smaller dihedral angel to 33.2° and much reduced energy gap to 2.46 eV, as compared to that of PFBT NPs. Importantly, through controlling surfactant concentrations from 40 g·L −1 to 2.5 g·L −1 during the miniemulsion polymerization, the particles size can be accordingly changed from even 88 to 210 nm. Furthermore, the particles show extinction coefficient of 2.82 × 10 4  M −1 ·cm −1 at 648 nm, photoluminescence quantum yields c.a. 2.4% and fluorescence lifetime c.a. 1.26 ns, respectively. Moreover, the PFTA NPs exhibit biocompatibility, good colloidal stability and bright fluorescence signals to clearly pinpoint breast cancer cells, with a trend that smaller NP size, higher cellular uptake. This work demonstrates the promise of miniemulsion polymerization as a facile method to fabricate NIR CPNPs for bioimaging.

Enabling Sensitive and Stable X-ray Detection in a 2D Trilayered Hybrid Perovskite with Strong F–π Interactions

Peixuan Zhu,Huawei Yang,Lemei Long,Panpan Yu,Chengmin Ji,Zeng-Kui Zhu,Ying Zeng,Shihai You,Junhua Luo

Organic–inorganic hybrid perovskites integrate the advantages of organic and inorganic components, making them promising candidates for high-performance X-ray detection. However, severe ion migration under external voltage makes it a tough challenge to realize high sensitivity and operational stability simultaneously in practical application. Here, we report a two-dimensional (2D) trilayered hybrid perovskite with F-substituted aromatic spacers, (FBZA)2(MA)2Pb3Br10 (1, FBZA = 4-fluorobenzylamine, MA = methylamine). The thick inorganic slabs endow 1 with efficient carrier transport paths, achieving a superior mobility-lifetime product of 1.3 × 10–3 cm2 V–1, much higher than most of 2D perovskites. Indeed, a high sensitivity of 2818.2 μC Gy-1 cm–2 and a low detection of limit (LOD) of 43.7 nGy s–1, as well as a low dark current drift of 1.61 × 10–7 nA cm–1 s–1 V–1 under a bias of 100 V, suggests its great potential on sensitive and stable X-ray detection. The stable and reliable response to long-time X-ray irradiation of high dose rate under large working voltage further verifies its operational stability. This research develops a multilayered 2D perovskite with strong interlayer interactions, successfully achieving high-sensitivity and high-stability X-ray detection, which sheds light on the design and construction of high-performance perovskite-based X-ray detectors in the future.