International Journal of Minerals Metallurgy and Materials
·
2021
·Vol. 28
·期 2
·305-316
·
IF 2.232
Wang Hao-yang,Cheng Xue,Li Xiao-feng,Pan Ji-min,Hu Jun-hua
To probe the coupling effect of the electron and Li ion conductivities in Ni-rich layered materials (LiNi 0.8 Co 0.15 Al 0.05 O 2 , NCA), lithium lanthanum titanate (LLTO) nanofiber and carbon-coated LLTO fiber (LLTO@C) materials were introduced to polyvinylidene difluoride in a cathode. The enhancement of the conductivity was indicated by the suppressed impedance and polarization. At 1 and 5 C, the cathodes with coupling conductive paths had a more stable cycling performance. The coupling mechanism was analyzed based on the chemical state and structure evolution of NCA after cycling for 200 cycles at 5 C. In the pristine cathode, the propagation of lattice damaged regions, which consist of high-density edge-dislocation walls, destroyed the bulk integrity of NCA. In addition, the formation of a rock-salt phase on the surface of NCA caused a capacity loss. In contrast, in the LLTO@C modified cathode, although the formation of dislocation-driven atomic lattice broken regions and cation mixing occurred, they were limited to a scale of several atoms, which retarded the generation of the rock-salt phase and resulted in a pre-eminent capacity retention. Only NiO phase “pitting” occurred. A mechanism based on the synergistic transport of Li ions and electrons was proposed.
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高影响因子
MICROCHIMICA ACTA
·
2018
·Vol. 185
·期 3
·1-9
·
IF 5.705
Li Yuemei,Li Yongmei,Wang Rui,Zheng Wei
Optical sensing of temperature by measurement of the ratio of the intensities of the 700 nm emission and the 800 nm emission of Ga(III)-doped ZnO (GZO) nanoparticles (NPs) and of GZO NPs coated with a silica shell are demonstrated at 980 nm excitation. It is found that the relative sensitivity of SiO 2 @Yb/Tm/GZO is 6.2% K −1 at a temperature of 693 K. This is ~3.4 times higher than that of Yb/Tm/GZO NPs. Obviously, the SiO 2 shell structure decreases the rate of the nonradiative decay. The decay time of the 800 nm emission of the Yb/Tm/GZO NPs (15 mol% Ga; 7 mol% Yb; 0.5 mol% Tm) displays a biexponential decay with a dominant decay time of 148 μs and a second decay time of ~412 μs. The lifetime of the Yb/Tm/GZO NPs at 293 K, and of the SiO 2 @Yb/Tm/GZO NPs are ~412 μs. Both the Yb/Tm/GZO and SiO 2 @Yb/Tm/GZO can be used up to 693 K. These results indicate that the SiO 2 shell on the Yb/Tm/GZO is beneficial in terms of sensitivity and resolution.
The enhancement the decay time and thermal sensitivity in the SiO 2 @Yb/Tm/GZO shell@core structure have been studied compared to the Ga(III)-doped Yb/Tm-doped ZnO (Yb/Tm/GZO). The SiO 2 @Yb/Tm/GZO have good thermal accuracy up to 693 °C.
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JOURNAL OF SOLID STATE ELECTROCHEMISTRY
·
2023
·Vol. 27
·期 12
·3315-3324
·
IF 2.5
Kuang Juner,Li Xiang,Li Yisa,Zhong Yu,Gu Changdong,Xia Xinhui,Wang Xiuli,Tu Jiangping
Polyethylene oxide (PEO)-based solid electrolytes, which exhibit ideal extensibility and wide electrochemical window, are considered as one of the most promising candidates for all solid-state sodium batteries (ASSSBs). However, the low mechanical strength and low ionic conductivity hinder their application. Herein, electrospun MgAl 2 O 4 nanofibers are complexed with PEO/NaClO 4 to enhance the mechanical and thermal stability. Determined by 23 Na solid-state nuclear magnetic resonance spectroscopy combined with first-principle calculations, the adsorption energy of ClO 4 − on the MgAl 2 O 4 surface is far higher than that on PEO, which facilitates the dissociation of Na + and ClO 4 − , thereby enabling a fast transport of Na + by the introduction of MgAl 2 O 4 in the polymer electrolyte. The ionic conductivity is enhanced to 1.89 × 10 −4 S cm −1 from 8.46 × 10 −5 S cm −1 at 55 °C, and the Na + transfer number is improved to 0.55 from 0.26 in the composite electrolyte. The Na//(PEO/MgAl 2 O 4 /NaClO 4 )//Na symmetric cell can cycle for over 400 h at a current density of 0.05 mA cm −2 and a cut-off capacity of 0.05 mAh cm −2 while the ASSSBs incorporating the polymer composite electrolyte also exhibit notable rate and cycle performances.
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JOURNAL OF POROUS MATERIALS
·
2019
·Vol. 26
·期 5
·1369-1375
·
IF 1.947
Guo Tan,Chen Rong,Wu Shimin,Zhang Lijing,Yun Shan,Zhang Jiadong,Li Yanxing,Li Huaju,Huang Aibing
In this work, melamine sponge (MS) reinforced methyltrimethoxysilane (MTMS)-based silica aerogels were fabricated via a sol–gel method followed by fast microwave drying. The aerogel composites with large size (20 × 20 × 2 cm) can be dried within 30 min. The MS/MTMS-based silica aerogel composites exhibit macro-pore structure, low density (95–178 kg m −3 ), excellent integrity and bending flexibility, together with high mechanical strength (Young’s modulus up to 4.787 MPa). Moreover, the superhydrophobicity with a contact angle as high as 164° and a low thermal conductivity of 0.033 W m −1 K −1 are demonstrated. Our work offers an effective method to fabricate high-quality aerogel composites as promising candidates for energy-saving applications.
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JOURNAL OF NANOPARTICLE RESEARCH
·
2012
·Vol. 15
·期 1
·1-12
·
IF 3.287
Yang Jintao,Yan Xiaohui,Chen Feng,Fan Ping,Zhong Mingqiang
In this paper, graphite oxide (GO) platelets functionalized by poly(ionic liquid) brushes were prepared by surface-initiated atom transfer radical polymerization (SI-ATRP). The chemical reduction of these functionalized platelets was also investigated. The functionalized platelets and their reduced products were characterized and confirmed by Fourier transform infrared spectroscopy, thermogravimetric analysis, ζ potential measurements, four-probe electrical measurements, and high-resolution transmission electron microscopy. Results demonstrated that the poly(ionic liquid) brushes could be grafted from the GO surface by SI-ATRP. The surface charges of the GO platelets surface transformed from negative to positive. Upon reduction by hydrazine, the functionalized platelets were partially reduced, as suggested by the observation that reduced GO exhibits electrical conductivity three magnitudes higher than that of original GO. Although partially reduced GO platelets were not as conductive as reduced GO without functionalization, they can be homogenously dispersed in water due to the presence of poly(ionic liquids) brushes.
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JOURNAL OF ELECTRONIC MATERIALS
·
2019
·Vol. 48
·期 5
·2745-2753
·
IF 1.676
Zhan Haijiao,Guo Jiayu,Shen Jiali,Wang Xiaorong,Fan Zhonghua,Guo Bing,Liu Wei,Shen Hangyan
Silver microparticles have inspired much research interest due to their enhanced properties for use in optical, electric, catalytic, and magnetic applications. One such use is as electrically conductive filler for printed electronics. A manufacturing approach has been developed to prepare low-curing-temperature silver pastes. Firstly, silver flakes were synthesized directly by a one-step aqueous-phase reduction reaction, using silver nitrate as silver salt precursor and iron(II) sulfate heptahydrate as reducing agent. Various silver flake samples were synthesized by controlling experimental parameters such as the reaction temperature, surfactant concentration, and reducing agent concentration. The obtained silver powders were characterized by x-ray diffraction analysis, scanning electron microscopy, and dynamic light scattering measurements. The results revealed that the morphology of the silver powders was a plate-like structure with diameter of 1 μ m to 1.5 μ m and thickness of 30 nm. The prepared silver flakes were then used directly without ball milling to prepare low-curing-temperature silver pastes. The bulk resistivity of a line screen-printed using silver paste containing 48 wt.% (34 ± 5 vol.%) silver flakes and cured at 140°C for 30 min in air was about (1.773 ± 0.118) × 10 −6 Ω m. More importantly, the prepared screen-printed patterns exhibited excellent durability in terms of peel strength and folding endurance.
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高影响因子
IRANIAN POLYMER JOURNAL
·
2012
·Vol. 21
·期 10
·721-730
·
IF 0.936
Yan Zhenlong,Liu Weiqu,Gao Nan,Sun Yue,Chen Haisheng
A novel dicarboxyl-terminated poly(2,2,3,4,4,4-hexafluorobutyl acrylate) oligomer (CTHFA) was synthesized through metal-free anionic polymerization and hydrolysis reaction. Chemical structures of CTHFA were characterized by gel permeation chromatography and 1 H NMR. Two types of CTHFA with different chain lengths were initially used as an efficient surface modifier to improve the surface properties of epoxy resin, at the content of CTHFA ranging between 0 and 8 wt%. We minimized the amounts of the CTHFA used to achieve a high hydrophobic surface that was not obviously affected by the thermal properties of the epoxy resin. Surface properties and surface composition of the designed fluorinated epoxy resin were investigated by the contact angle and X-ray photoelectron spectroscopy (XPS). Modified epoxy resin with 5 wt% CTHFA containing longer chain length showed excellent hydrophobic surface properties (a high water contact angle about 115° and low surface energy 14.12 mN/m 2 ) while the modified epoxy resin with 5 wt% CTHFA containing shorter chain length did not. XPS analyses indicated that the 5 wt% of fluorinated CTHFA epoxy resin with long macromolecular-chain enhanced more fluorinated groups’ migration to the surface than the fluorinated CTHFA-modified epoxy resin with short macromolecular-chain at the same content. Moreover, thermal properties of CTHFA-modified epoxy resin were also investigated.
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FIBERS AND POLYMERS
·
2021
·Vol. 22
·期 1
·141-148
·
IF 2.153
Jia Weini,Li Shirong,Luo Zhengxin,Yu Hainan,Zhu Wenjun,Mao Qinghui,Zhang Xiaoli,Liang Zhijie,Dong Aixue
Due to the damage of scalp because of chemical dyes, increasing attention had been paid to the ecological dyeing of human hair. To address the need for ecological restoration and dyeing of human hair, herein, a novel approach has been proposed via laccase-mediated in situ oxidation of dihydroxy phenylalanine (dopamine). As laccase can catalyze dopamine oxidation and then polymerization to produce strongly colored polymers, different biological coloration processes of human hair based on this process were investigated: (i) Human hair was treated with laccase alone; (ii) The absorption of human hair with dopamine, followed by further catalysis of air; (iii) The absorption of human hair with dopamine, followed by further catalysis of laccase; (iv) Simultaneous laccase-mediated polymerization and dyeing of human hair; and (v) Polymerization of Dopamine with laccase and then dyeing human hair. The surface properties of dyed hair were evaluated in terms of ultraviolet (UV)-protection, color fastness, Fourier transforming infrared spectrum (FT-IR), optical microscope, and scanning electron microscopy (SEM). The results show that best hair dyeing effect was achieved via simultaneous laccase-mediated polymerization and dyeing. The dyed hair obtained K/S values of 28, light fastness of level 5, and UPF of 100 + . The optical microscope and SEM observations show that the surface of colored hair fibers was covered with thin burrs, which can be attributed to polydopamine attached with physical adhesive force and covalent reaction. FT-IR analysis shows that functional groups were present on the surface of the dyed hair which can be considered as introduction of hydroxyl radical groups. This biological stain technique may be widely used in dyeing of hair with black color.
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高影响因子
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
·
2022
·Vol. 128
·期 10
·1-9
·
IF 2.983
Zhang Yawen,Ding Huizhen,Yan Bin,Lin Pei,Wu Di,Shi Zhifeng,Chen Xu,Tian Yongtao,Li Xinjian
Recently, highly flexible strain sensors have been widely studied based on the conductive polymer composites, due to their potential applications in wearable electronics, soft robots, and human–machine interfaces. Herein, we fabricate the flexible MWCNT line/Ecoflex strain sensors by 3D printing technology to investigate the effects of preparation conditions on the performance of sensors, and find that gage factor (GF) of such sensors is effected by concentration of MWCNT/IPA solution and curing time of Ecoflex pre-polymer film. Among the obtained samples, the sensor prepared by 2 wt% MWCNT/IPA solution with curing time of 12 min has the highest gage factor, about ~ 23.87. The sensors can detect or monitor subtle motions of facial muscle, breath and pulse, and possess wide linear range besides good repeatability and excellent durability. Meanwhile, the prepared sensors were designed into a 4 × 4 array, and the array achieved monitoring of spatial distribution of the applied pressure. Our strategy could be used to fabricate flexible strain sensors with wide linear range, which facilitate further integration to achieve potential applications in detection of human activity, electronic skin, and soft robots.
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高影响因子
KOREAN JOURNAL OF CHEMICAL ENGINEERING
·
2021
·Vol. 38
·期 9
·1810-1817
·
IF 3.309
Luan Wenwen,Wang Chunyu,Zeng Zuoxiang,Xue Weilan,He Xuelian,Bai Yu
The hydrolysis kinetics of polyvinyl butyral (PVB) was studied in ethanol/water mixed solvents in the temperature range of 339.15-355.15 K, and a three-step hypothesis was proposed to describe the hydrolysis process. The influences of stirring speed, ethanol content and temperature on the hydrolysis of PVB were investigated, and an induction period (IP) phenomenon was found in the process of PVB hydrolysis. The ethanol content in the mixed solvents has a great influence on IP, which is due to the formation of the two kinds of water-ethanol clusters in the system. Temperature influences the IP by changing the catalytic activity of hydroxylamine hydrochloride (HH) on the hydrolysis of PVB. The shrinking core models with three controlling steps were used to fit the kinetic data, and the results indicate that the model controlled by chemical reaction is suitable to describe the kinetic behavior of PVB hydrolysis.
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高影响因子
CHROMATOGRAPHIA
·
2024
·
IF 1.2
Chen Shaoman,Li Xican,Li Chunhou,Cai Rongxin,Chen Ban,Jiang Guihua,Liang Yongbai,Chen Xu
Violae herba (Zihuadiding) is a common Chinese herbal medicine. The current Chinese Pharmacopeia (ChP) defines Viola yedoensis Makino as the sole plant origin and esculetin as its sole quality-marker (Q-marker). Esculetin, however, occurs in some counterfeits as well. This implies that current ChP criterion actually cannot recognize the counterfeits of V. yedoensis . The study thus created a specialized MS library using ultra-high-performance liquid chromatography with quadrupole-orbitrap tandem mass spectrometry (UHPLC- Q -Orbitrap-MS/MS) analysis. Through library-comparison, 36 compounds were putatively identified from V. yedoensis ; especially, four isomers were successfully distinguished, that is, vitexin vs isovitexin and schaftoside vs isoschaftoside. The subsequent UHPLC- Q -Orbitrap-MS/MS semi-quantification suggested that the chemical contents of 36 compounds varied from 0.001 to 1.958% and the old Q-marker esculetin had high content (0.484 ± 0.028%). According to the relevant principles, flavonoid luteolin was proposed as the new and additional Q-marker. The proposal offers a preliminary evidence to recognize seven adulterations (or counterfeits) of V. yedoensis .
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CHEMICAL PAPERS
·
2021
·Vol. 75
·期 10
·5561-5569
·
IF 2.097
Shao Tantan,Gong Yilu,Chen Xiaolong,Chen Lijun
Novel self-crosslinking long fluorocarbon acrylate polymer latex has been successfully prepared by semi-continuous seeded emulsion polymerization with methyl methacrylate(MMA), butyl acrylate (BA), dodecafluoroheptyl methacrylate (DFMA) and hydroxypropyl methacrylate(HPMA) as main monomers, 10-undecylenic acid (10-UA) and diallyl phthalate (DAP) as functional monomers. During the latex polymerization, the monomers were emulsified by the mixed surfactants of nonionic surfactant alcohol ether glycoside (AEG) and anionic surfactant sodium dodecylbenzene sulfonate (SDBS), and initiated by potassium persulfate (KPS). The resultant latex showed excellent properties. The chemical composition of latex was determined with Fourier transform infrared spectrum (FTIR) and the glass transition temperature (Tg) of polymer was detected by differential scanning calorimetry (DSC) and the water repellency of the prepared film was measured by water contact angle measurement (WCA). The reaction conditions were optimized and obtained as follows: the optimal monomer dosage was MMA: BA: DFMA: HPMA = 12.75:12.75:0.9:1.2, the amount of 10-UA and DAP was both 4% of all monomers, the dosage of AEG: SDBS was 5% (1:1) and KPS was 0.5%, respectively. The result indicated that the conversion of the mixed monomers was more than 98% and the coagulation was less than 1% and the resultant latex also had the outstanding appearance and latex performance.
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高影响因子
危险品化学品经营许可证（带存储）