JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE
·
2020
·Vol. 29
·期 12
·7971-7980
·
IF 1.652
Wang Bin,Du Jinjing,Gao Shoukun,Zhou Meng,Li Erhu,Li Linbo
NiFe 2 O 4 /nano-TiN ceramics were synthesized by a two-step cold-pressing sintering process. Sintering behavior, fracture morphology, mechanical performance and high-temperature conductivity were investigated. The results indicated that besides NiO and NiFe 2 O 4 , new Ni 3 TiO 5 and metallic phases (iron and nickel) formed in the sintered samples. TiN accelerated the grain growth along with considerable quantity of micro-pores in the sintered samples. Compared to the un-doped samples, the temperature for the onset of sintering of the NiO-Fe 2 O 3 -2.0 wt.% TiN system decreased from 1093 to 985 °C. TiN addition changed the sintering mechanism of the NiO-Fe 2 O 3 from grain boundary diffusion to volume diffusion. TiN additions reduce the apparent sintering activation energy and porosities and improve the density, bending strength, and pyroconductivity. Three-dimensional fracture morphology of the composite ceramics synthesized under argon atmosphere, exhibits self-similarity characteristics and the fractal dimension for NiFe 2 O 4 -1.0 wt.% TiN ceramics is 2.0813.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
DOI
高影响因子
FUEL PROCESSING TECHNOLOGY
·
2016
·
IF 3.847
Yan-Na Han,Zong-Qing Bai,Jun-Jie Liao,Jin Bai,Xin Dai,Xiao Li,Jun-Li Xu,Wen Li
Oxygen functional groups as primary adsorption site of water are one of key factors controlling water re-adsorption and drying behaviors of brown coal . The dewatering energy of brown coal because of different oxygen functional groups is still unclear. Thus, two kinds of oxidized brown coal samples carrying more phenolic hydroxyl or carboxyl groups with similar pore structures were chosen. The concentrations of different water forms of the samples were determined from the moisture holding capacity at constant humidity and temperature and from the results of dewatering experiments analyzed by thermogravimetry coupled with differential scanning calorimetry . The results showed that the concentrations of three forms of water, i.e. free water, capillary water , and molecular water, showed good correlations with concentration of carboxyl groups. Comparison of 1 H NMR analysis of dried and moisturized samples showed that the types of oxygen functional groups predominantly affected the water environment in coal. IR spectra of dried and adsorbed D 2 O samples showed that OH–π hydrogen bond due to carboxyl groups was easier broken than that due to phenolic hydroxyl groups . The water desorption energy of primary site and dewatering energy of samples with more carboxyl groups were lower than that of samples with more phenolic hydroxyl groups, because hydrogen bonding energy of water bonded to hydroxyl oxygen of carboxyl groups was lower than that of water bonded to hydroxyl oxygen of phenolic hydroxyl groups.
研究领域:
能源科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
AICHE JOURNAL
·
2021
·Vol. 67
·期 7
·e17298
·
IF 3.993
Xueyan Sun,Zhigang Wang,Chong Li,Lijing Zhang,Wenbo Yang,Shengyang Tao
Holistic catalytic reactors with fractal structures have attracted growing attention in heterogeneous reactions because of their advantages of improved mass transfer and easy separation. Herein, a cost-efficient and straightforward design strategy that combined three-dimensional printing and electroless deposition was presented to construct dynamic, holistic stirred reactors with the fractal structure. The conversion factor α of the fractal impeller is 65.01 mmol m −2 h −1 with a large volume of reactant (80 ml), which is 1.7 times that of the normal impeller with the same loading of Ag catalysts. Experimental results and simulation analysis demonstrate that the fractal impeller significantly improves the catalytic performance by enhancing mass transfer and spatial dispersion in the reaction. Moreover, the holistic impeller could be reused 10 times without obvious loss of catalytic performance, and easily separated from the reaction system. The structural design of fractal reactors will open the way for high-efficiency dynamic heterogeneous catalytic reactors.
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2024
·Vol. 34
·期 29
·2401490
·
IF 18.5
Bolong Wang,Bo Ma,Ke Wang,Huijie Zhang,Zeqi Zhang,Tao Song,Shuyan Wang,Mingzhu Chen,Shiji Li,Qiang Wang,Hao-Li Zhang
The compelling demand for laser protection both for civil and defense use calls for new-generation nonlinear optical materials. Chemical vapor deposition (CVD) techniques provide extra tricks to modulate crystal optical nonlinearity through fractal growth. The synthesized 2D NbSe 2 and its fractal structures exhibit giant, broadband laser attenuation behaviors extending into the near Infrared (NIR) range. Particularly, the optical limiting performance generally correlates with the fractal dimension, where Fractal NbSe 2 demonstrates enhanced third-order optical nonlinearity at a huge nonlinear absorption coefficient of 9.7 × 10 −4 m W −1 and an ultralow starting threshold of 5 mJ cm −2 at 532 nm. Various techniques include femtosecond spectroscopy, Density functional theory (DFT) calculation and Kelvin probe force microscopy disclose the origin of the strong nonlinearity of the 2D NbSe 2 crystals, and suggest the formation of edge states and overall faster carrier dynamics, larger surface contact potential difference NbSe 2 fractals contribute to their even augmented nonlinear responses. Fractal engineering thus opens new avenues to fabricate highly efficient laser protection materials, and the blocking of intense beam (a large attenuation factor over 13.3 dB at 532 nm) while allowing transmission of weak one (a high linear optical transmittance over 80%) fulfills the much desired “smart” defense.
研究领域:
材料科学
·
光学
·
凝聚态物理
✓ 已验证
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2025
·
IF 19
Ningfei Sun,Shuolei Zhang,Xingyu Liu,Peng Zhao,Xiaobo Xue,Nyachieo Kennedy Momanyi,Jianyu Sun,Limin Liu,Xiaoguang Wei,Ling Li,Yong Xie
Fractal plasmonic nanoantennas are widely used in plasmon-enhanced infrared spectroscopy and multiband sensing applications due to their inherent broadband and multispectral characteristics. However, conventional fractal antennas are typically fabricated by high-cost, unscalable, and complicated lithography processes. The inevitable diffraction limit restricts the fabrication of higher-order fractals and the improvement of multiband infrared response. In this study, a lithography-free Au fractal nanoantenna platform is developed via film dewetting. The antennas can support multiple resonances over a broad spectral range spanning from near-infrared to mid-infrared. The fractal orders can be controlled by adjusting dewetting times. Moreover, due to the spontaneous fractal growth mechanism, the iteration number is theoretically unlimited. Through electromagnetic field simulation and infrared spectroscopy, the fractal order-dependent multiband resonance mode and dense “hot spots” enabled electric-field enhancement are revealed. Based on the infrared-enhanced antenna, a minimum detection limit of 6 nm for the thickness of poly(methyl methacrylate) nanolayers is achieved. Additionally, a noninvasive sensor concept for glucose molecules in aqueous solution is demonstrated. This study presents a lithography-free approach for constructing high-generation and large-area fractal nanoantennas with multiband resonance capabilities, which holds great promise for trace detection and high-sensitivity biochemical sensing of various analytes in the near- to mid-infrared spectral region.
研究领域:
纳米光子学
·
等离激元学
·
红外传感
·
纳米天线
·
薄膜技术
·
生化传感
·
光学材料
✓ 已验证
产品关联
DOI
高影响因子
iScience
·
2024
·
IF 4.6
Yan Liu,Xiaojing Liu,Hui He,Tengfei Zhang,Xiang Chai
Fouling deposit on nuclear fuel cladding causes wick boiling and boron hideout, resulting in localized corrosion and power shift with great potential security and economic risks. Herein, a cost-effective time-saving adjustable reproduction method combining sol-gel with ceramic sintering is presented to enable wide coverage of fouling’s morphologies and microstructures. Based on fractal analysis, structurally self-similar fouling deposits from different reactors conform to proposed porosity-fractal dimension law under 3% relative error. Wick boiling and boron hideout numerical simulation based on fractal dimension is implemented to treat different morphologies and structures in a unified way. Cladding surface underneath fouling deposit has a maximum 9.243 K temperature increasement due to thermal resistance, and H 3 BO 3 is concentrated 11.274 times by mean of wick boiling, causing Li 2 B 4 O 7 precipitation under extreme conditions with low porosity and high heat flux. The insights in this study provide a precise approach for quantitative evaluation of localized corrosion and power shift.
研究领域:
核能工程
·
材料科学
·
热物理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Nano
·
2023
·
IF 17.1
Shuo Yang,Chenxi Zhao,Yunhao Yang,Jing Ren,Shengjie Ling
Animal silk is usually considered to exist as a solid fiber with a highly ordered structure, formed by the hierarchical assembly starting from a single silk fibroin (SF) chain. However, this study showed that silk protein molecules existed in the form of a fractal network structure in aqueous solution, rather than as a single chain. This type of network was relatively rigid with low fractal dimension. Finite element analysis revealed that this network structure significantly helped in the stable storage of SF prior to the spinning process and in the rapid formation of a β-sheeted nanocrystalline and nematic texture during spinning. Further, the strong but brittle mechanical properties of Bombyx mori silk could also be well-explained through the fractal network model of silk fibroin. The strength was mainly derived from the dual network structure, consisting of nodes and β-sheet cross-links, whereas the brittleness could be attributed to the rigidity of the SF chains between these nodes and cross-links. In summary, this study presents insights from network topology for understanding the spinning process of natural silk and the structure–property relationship in silk materials.
研究领域:
生物材料学
·
分子生物学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF CHEMICAL EDUCATION
·
2024
·
IF 2.5
Haibo Zhang,Qiong Ding,Ruohan Li,Weihong Chen,Peng Wang
Liquid metals are widely applied in various fields, including chemistry, catalysis, energy storage, chemical sensing, and stretchable electronics, due to their unique deformabilities. However, their behavior under a rod or ring electrode has never been analyzed. Furthermore, research on the deformation behavior of eutectic Ga–In (EGaIn), the most commonly used Ga-based liquid metal, under electric fields of varying intensities and shapes is lacking. Therefore, investigating the deformation behavior of liquid metals under electric fields is expected to contribute to the accurate regulation of their morphologies. To this end, herein, an electrochemical device was fabricated using EGaIn, and experiments were conducted by adjusting the potential and the cathode shape. Further, the mechanism of the deformation was analyzed in detail. When a potential was applied, EGaIn droplets deformed into fractal dendrites under circular, polygonal, and nonpolygonal electric fields. Dendrite symmetry was influenced by the cathode shape, as the resulting electric fields varied in shape. The results of this study will aid in precisely controlling the behaviors of LMs and their alloys using electric fields. This topic is suitable for upper-division undergraduates who possess a basic understanding of electrochemistry. Through these experiments, students may explore the effects of potential on the morphology of EGaIn and analyze experimental phenomena such as electrowetting, dendrite formation, and surface oxidation, thereby developing a preliminary understanding of interfacial tension and electrocapillarity. Additionally, these experiments encourage undergraduates to actively participate in laboratory work, which helps foster their enthusiasm for chemistry.
研究领域:
材料科学
·
电化学
·
物理学
✓ 已验证
DOI
高影响因子
PHYSICS OF FLUIDS
·
2024
·Vol. 36
·期 11
·
IF 4.1
Chen Xinkun,Zhai Junlong,Chen Xueye
The traditional lipid preparation methods are complex, time-consuming, and consume a large amount of reagents, increasing costs and difficulties. Although microfluidic technology is considered a promising solution, achieving controllable liposome production with a simple and inexpensive microfluidic mixing device remains an important problem. This paper presents a wall-type micro-mixer based on coastal zone fractals. Four parameters related to the geometric shape of the coastline fractal in the microchannel are used as design variables, and the mixing index is the objective function. Single-objective optimization numerical analysis of the primary wall-type fractal baffle micromixer under four Reynolds numbers conditions yields the optimal structural configuration. Visualization experiments verify the correctness and accuracy of the numerical simulation, and the optimized mixer is used to produce liposomes. The results show that the micro-mixer with the optimal double-sidewall cross arrangement enhances chaotic convection and improves mixing efficiency. At Re = 0.1 and Re = 100, the mixing efficiency reaches 99%, 50.44% higher than the reference design. By changing the relative flow rates of lipid and aqueous solutions, microfluidic blank liposomes with a particle size of 165.12 ± 11.6 nm and a polydispersity index of 0.35± are obtained. This wall-type fractal micro-mixer has broad application prospects due to its high mixing efficiency.
研究领域:
药剂学
·
生物工程
·
化学工程
✓ 已验证
DOI
高影响因子
Nanomaterials
·
2023
·Vol. 13
·期 12
·1860
·
IF 5.3
Mingxuan Zhang,Jiawei Zhou,Chunlei Wan,Ming Liu,Xia Wu,Jihong Sun
Clinoptilolite (CP) was successfully synthesized via a hydrothermal route in the presence of polyethylene glycol (PEG), and it was then delaminated by washing using Zn2+containing acid. HKUST-1, as one kind of the Cu-based MOFs, showed a high CO2adsorption capacity owing to its large pore volume and specific surface area. In the present work, we selected one of the most efficient ways for preparing the HKUST-1@CP compounds via coordination between exchanged Cu2+and ligand (trimesic acid). Their structural and textural properties were characterized by XRD, SAXS, N2sorption isotherms, SEM, and TG-DSC profiles. Particularly, the effect of the additive PEG (average molecular weight of 600) on the induction (nucleation) periods and growth behaviors were detailed and investigated in the hydrothermal crystallization procedures of synthetic CPs. The corresponding activation energies of induction (En) and growth (Eg) periods during crystallization intervals were calculated. Meanwhile, the pore size of the inter-particles of HKUST-1@CP was 14.16 nm, and the BET specific area and pore volume were 55.2 m2/g and 0.20 cm3/g, respectively. Their CO2and CH4adsorption capacities and selectivity were preliminarily explored, showing 0.93 mmol/g for HKUST-1@CP at 298 K with the highest selective factor of 5.87 for CO2/CH4, and the dynamic separation performance was evaluated in column breakthrough experiments. These results suggested an efficient way of preparing zeolites and MOFs composites that is conducive to being a promising adsorbent for applications in gas separation.Keywords:clinoptilolite;HKUST-1;composites;fractal structures;delamination;adsorptive separations
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MATERIALS CHEMISTRY AND PHYSICS
·
2017
·
IF 2.084
Qian Wang,Xiao Qi Jin,Ji Hong Sun,Shi Yang Bai,Xia Wu
The polymer/SiO 2 hybrid material (P/SiO 2 -MPS) with core-shell structure were synthesized using the dense nanosilica spheres (DNSS) as core and pH responsive poly(acrylic acid) (PAA) as a shell. Meanwhile, using ibuprofen (IBU) as a model drug, the structure and properties of obtained P/SiO 2 -MPS were characterized by SEM, TEM , FT-IR, TGA , EDS, NMR, XRD , DLS and SAXS . The results elucidated that PAA was successfully incorporated onto the surface of DNSS, and thereafter the thickness of PAA shell could be controlled by adjusting the additive amount of AA. Particularly, SAXS patterns evidently exhibited that P/SiO 2 -MPS before IBU-loading and after releasing possessed the surface fractal feature, which increased from 2.19 for SiO 2 -MPS, to 2.41 for P/SiO 2 -MPS, to 2.54 for IBU-loaded P/SiO 2 -MPS, and to 2.65 for IBU-released P/SiO 2 -MPS. Moreover, the IBU-releasing percentage of three samples (P/SiO 2 -MPS-1, P/SiO 2 -MPS-3 and P/SiO 2 -MPS-5) increased gradually at both pH 3.0 and 7.4 with the enlarged thickness of PAA shells, while for P/SiO 2 -MPS-7 with the thickest PAA layer, its release rate was not more than that of P/SiO 2 -MPS-5. Therefore, IBU molecules were hindered from passing through PAA layer. Furthermore, the IBU loading of P/SiO 2 -MPS was fitted into the pseudo-second-order model, while its drug-release kinetic profile was favorable to Korsmeyer-Peppas model. These observations evidently demonstrated that the surface effects of P/SiO 2 -MPS on its surface fractal feature and the diffusion of IBU delivery were very important, and therefore its mechanism was essentially proposed.
研究领域:
材料科学
·
药物递送
·
生物医学工程
✓ 已验证
DOI
高影响因子
ENERGY
·
2025
·
IF 9.4
Guopeng Chen,Shangzhen Xie,Congji Zhang,Zhiguang Guo
Amidst the growing global emphasis on energy conservation, environmental protection, and climate change mitigation, solar photovoltaic panels have garnered widespread recognition as a sustainable energy solution. However, prolonged exposure to sunlight inevitably raises the temperature of photovoltaic panels, resulting in a reduction in their efficiency and service life. To tackle these challenges, there is a pressing need to develop advanced photovoltaic thermal management technologies. This article introduces a novel bio-inspired fractal vein-like structure integrated with hygroscopic salts for efficient thermal management of photovoltaic (PV) systems. By incorporating hygroscopic salts into the hydrogel, a cyclic process of water molecule adsorption and desorption is realized by mimicking sweat cooling. The 3D-printed aluminum alloy bio-inspired leaf vein serves as heat transfer skeleton, fast transferring the heat to the hydrogel with large enthalpy, effectively reduces the temperature of the photovoltaic cell and enhances its photoelectric conversion efficiency. Experimental results demonstrate that this thermal management system could reduce the maximum temperature of the photovoltaic cell surface by 18.41 °C under laboratory conditions and by 9.02 °C in outdoor applications, increasing the maximum output power by 38.09 %. This thermal management strategy offers a reliable, efficient, and environmentally friendly solution for the photovoltaic cells cooling.
研究领域:
材料科学
·
能源工程
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）