Jiecai Han

Harbin Institute of Technology, Charbin, Heilongjiang Sheng, China

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Publications (204)517.11 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The coupling effect between nitrogen-vacancies (VN) and aluminum-interstitial sites (Ali) is investigated theoretically and experimentally in AlN helices. First-principles calculations predict a photoluminescence emission peak at approximately 600 nm in AlN doped with complex-defect (VNAli). A typical long afterglow (persistent luminescence) was observed in unintentionally doped AlN helices by introducing the complex-defect of (VNAli). An analysis of the luminescent characteristics indicated that the mechanism behind this afterglow is the complex-defect level and complex-defect density. These findings may further enrich the thoughts of defects in the wide band gap semiconductor of AlN.
    Nano Letters 09/2015; DOI:10.1021/acs.nanolett.5b02300 · 13.59 Impact Factor
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    ABSTRACT: Carbon-based nanomaterials provide an attractive perspective to replace precious Pt-based electrocatalysts for oxygen reduction reaction (ORR) to enhance the practical applications of fuel cells. Herein, we demonstrate a one-pot direct transformation from graphitic-phase C3N4 (g-C3N4) to nitrogen-doped graphene. g-C3N4, containing only C and N elements, acts as a self-sacrificing template to construct the framework of nitrogen-doped graphene. The relative contents of graphitic and pyridinic-N can be well-tuned by the controlled annealing process. The resulting nitrogen-doped graphene materials show excellent electrocatalytic activity toward ORR, and much enhanced durability and tolerance to methanol in contrast to the conventional Pt/C electrocatalyst in alkaline medium. It is determined that a higher content of N does not necessarily lead to enhanced electrocatalytic activity; rather, at a relatively low N content and a high ratio of graphitic-N/pyridinic-N, the nitrogen-doped graphene obtained by annealing at 900 °C (NGA900) provides the most promising activity for ORR. This study may provide further useful insights on the nature of ORR catalysis of carbon-based materials.
    ACS Applied Materials & Interfaces 08/2015; 7(35). DOI:10.1021/acsami.5b03845 · 6.72 Impact Factor
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    ABSTRACT: An original catalytic method has been proposed to synthesize carbon nanotubes (CNTs)–ZrB2–ZrO2 heterostructures using ZrB2 polymeric precursor. The pyrolysized gases from the ZrB2 polymeric precursor are identified to be the carbon sources for CNTs growth. A parametric study is conducted to control the CNTs growth by optimizing parameters such as synthesis temperature and catalyst content. Observations show that the in situ grown CNTs are homogeneously dispersed in the powders, and the structure and the amount of CNTs are significantly dependent on the synthesis parameters. There are two kinds of grown CNTs existed in the produced hybrid heterostructures: (i) the kinking structured CNTs that are disordered and incomplete graphitization; (ii) the improved and graphitized CNTs. The ZrB2 polymeric precursor during thermal pyrolysis provides capable of supplying substantial carbon source for CNTs nucleation and growth by homogeneous vapor–liquid–solid reactions.
    Journal of the American Ceramic Society 08/2015; DOI:10.1111/jace.13813 · 2.61 Impact Factor
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    ABSTRACT: Developing a simple and efficient method to organize nanoscale building blocks into ordered superstructures, understanding the mechanism for self-assembly and revealing the essential collective properties are crucial steps toward the practical use of nanostructures in nanotechnology-based applications. In this study, we showed that the high-yield formation of ZnO nanoparticle chains with micrometer length can be readily achieved by the variation of solvents from methanol to water. Spectroscopic studies confirmed the solvent effect on the surface properties of ZnO nanoparticles, which were found to be critical for the formation of anisotropic assemblies. Quantum mechanical calculations and all atom molecular dynamic simulations indicated the contribution of hydrogen bonding for stabilizing the structure in water. Dissipative particle dynamics further revealed the importance of solvent-nanoparticle interactions for promoting one-dimensional self-assembly. The branching of chains was found upon aging, resulting in the size increase of the ensembles and network formation. Steady-state and time-resolved luminescent spectroscopes, which probed the variation of defect-related emission, revealed stronger Forster resonance energy transfer (FRET) between nanoparticles when the chain networks were formed. The high efficiency of FRET quenching can be ascribed to the presence of multiple energy transfer channels, as well as the short internanoparticle distances and the dipole alignment.
    ACS Nano 05/2015; 9(6):5807-5817. DOI:10.1021/acsnano.5b00344 · 12.88 Impact Factor
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    ABSTRACT: Macroporous SiOC ceramics have been prepared by the pyrolysis of the preceramic precursor obtained from methyltrimethoxysilane and dimethyldimethoxysilane. The structural evolution of the sol-gel derived SiOC ceramics at high temperatures was investigated using SEM, TG, FTIR, XRD and Raman spectra. The SiOC xerogel exhibited a porous structure consisting of cross-linked spherical gel particles. The structural rearrangement appeared and the SiOC ceramic particles changed from spherical to irregular shape after thermal pyrolysis. The ceramic yield was found to be approximately 70% until 1400 °C, and decreased to 38% at 1600 °C owing to carbothermal reduction. The SiC nanorods were in situ formed from macroporous SiOC ceramic wall at 1600 °C. The β-SiC nanocrystals precipitated from the SiOC matrix at 1400 °C and grew up to 4.6 nm at 1600 °C. The graphitization degree of free carbon increased with the increase of pyrolysis temperature.
    Ceramics International 05/2015; DOI:10.1016/j.ceramint.2015.05.056 · 2.61 Impact Factor
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    ABSTRACT: Interface engineering has emerged as a fertile and efficacious approach to turn functional properties in the field of film systems. In this work, the interfacial properties of sputtered yttrium oxide films on zinc sulfide substrate (Y2O3/ZnS) were analyzed by transmission electron microscopy (TEM), X-ray photoelectron spectrum (XPS) depth profile and nano-scratch measurement. An interface layer with the depth of 20 nm between Y2O3 film and ZnS substrate was directly observed by TEM. Under different film growth conditions, although the interfacial features including interfacial width and composition distribution exhibit similar behavior, it is found that higher cohesive strength is obtained under a special substrate bias voltage of -160 V at low substrate temperature. Such an enhanced mechanical property can be understood by the role of physisorbed oxygen in the interfacial region, in which less physisorbed oxygen with van der Waals bonds leads to a strong adhesion. Our results provide a favorable strategy to achieve strong adhesion between oxide and sulfide at low temperature, which are urgent in future micro-electric applications.
    Applied Surface Science 05/2015; 351. DOI:10.1016/j.apsusc.2015.05.109 · 2.71 Impact Factor
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    ABSTRACT: In order to understand the growth behavior of yttrium oxide films driven by thermodynamics and kinetics, two fundamental growth parameters, substrate heating and biasing, were investigated to control film structure and properties comprehensively. We observed two distinct areas, normal deposition area (area 1) and abnormal deposition area (etching area, area 2) at different substrate bias voltages regardless of the substrate temperature. X-ray diffraction (XRD) results show that heating promotes cubic phase formation, whereas ion bombardment induces monoclinic phase growth. Atomic force microscopy (AFM) measurements exhibit that the ions slightly enlarge the surface islands in area 1, whereas they flatten and smoothen the surface in area 2. X-ray photoelectron spectroscopy (XPS) results demonstrate that high temperature suppresses the physisorbed oxygen, and the ion bombardment favorably selects oxygen etching in area 1, causing excess oxygen vacancies. This selectivity almost disappears in area 2. Furthermore, the refractive index and band gap can be enhanced by both substrate temperature and bias voltage. The surface wettability of films can be modulated by the surface chemical composition.
    Ceramics International 04/2015; 41(7). DOI:10.1016/j.ceramint.2015.03.165 · 2.61 Impact Factor
  • Yurong He · Yuanchun Liu · Xing Liu · Jiaqi Zhu · Jiecai Han
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    ABSTRACT: Materials for infrared domes are required to maintain good properties in harsh environments including mechanical strength, optical transmittance over a wide range of wavelengths and low emissivity. The purpose of this work is to sputter Y2O3 film onto a sapphire substrate by a radio frequency magnetron sputtering method and investigate the structural and thermal radiation properties of the films. In addition, the apparent emissivity of the coated sapphire is simulated for different film thicknesses at different temperatures. The experimental results show that the surface of the Y2O3 film is homogeneous, has a dense morphology and is totally polycrystalline. After being coated with the Y2O3 film, the transmission of the sapphire substrate is improved and the emissivity is decreased with increasing film thickness, especially at high temperatures. Simulation results show that apparent emissivity of a sapphire substrate at high temperatures can be reduced effectively by the Y2O3 film when the ratio of the thickness of Y2O3 film and sapphire substrate is larger than 0.01.
    Journal of Alloys and Compounds 04/2015; 627:438-445. DOI:10.1016/j.jallcom.2014.11.233 · 3.00 Impact Factor
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    ABSTRACT: In order to improve the oxidation-resistance of carbon-bonded carbon fiber composites, a multi-composition coating consisting of multi-layer ZrB2-SiC whiskers(SiCw)-Borosilicate/ZrB2-MoSi2-SiCw-Borosilicate, was prepared on the surface of ZrB2-modified carbon-bonded carbon fiber composites (M-CBCF) by a rapid sintering method in trace amounts of oxygen environment. The inner-layer ZrB2-SiCw -Borosilicate was first prepared by instantaneous vacuum-impregnation to seal the surface pores of M-CBCF, and the outer-layer ZrB2-MoSi2-SiCw -Borosilicate was obtained by slurry spraying. The multi-layer coated composites were embedded in graphite powders and sintered at 1723K for 10 min in atmosphere. The results showed that the prepared ZrB2-SiCw-Borosilicate/ZrB2-MoSi2-SiCw -Borosilicate coating had remarkable oxidation resistance and could protect M-CBCF from high- temperature erosion. The weight loss rate of the double-layer coated composites was only 0.44% after oxidation for 100min at 1773 K, while the weight loss rate of inner-layer coated composites reached 25.35%. The oxidation-resistance of multi-layer coating was mainly attributed to the high viscosity of glass phase, matched thermal expansion coefficient and the toughening effect of SiCw.
    Surface and Coatings Technology 03/2015; 270. DOI:10.1016/j.surfcoat.2015.03.014 · 2.00 Impact Factor
  • Jiaqi Zhu · Wenxin Cao · Mingli Yue · Ying Hou · Jiecai Han · Ming Yang
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    ABSTRACT: Small but strong carbon nanotubes (CNTs) are fillers of choice for composite reinforcement owing to their extraordinary modulus and strength. However, the mechanical properties of the nanocomposites are still much below those for mechanical parameters of individual nanotubes. The gap between the expectation and experimental results not only arises from imperfect dispersion and poor load transfer but also from the unavailability of strong polymers that can be effectively utilized within the composites of nanotubes. Aramid nanofibers (ANFs) with analogous morphological features to nanotubes represent a potential choice to complement nanotubes given their intrinsic high mechanical performance and the dispersible nature which enables solvent-based processing methods. In this work, we showed that composite films made from ANFs and multi-walled CNTs (MWCNTs) by vacuum-assisted flocculation (VAF) and vacuum-assisted layer-by-layer (LBL) assembly exhibited high ultimate strength of up to 383 MPa and Young's modulus (stiffness) of up to 35 GPa, which represent the highest values among all the reported random CNT nanocomposites. Detailed studies using different imaging and spectroscopic characterizations suggested that the multiple interfacial interactions between nanotubes and ANFs including hydrogen bonding and pi-pi stacking are likely the key parameters responsible for the observed mechanical improvement. Importantly, our studies further revealed the attractive thermo-mechanical characteristics of these nanocomposites with high thermal stability (up to 520 oC) and ultralow coefficients of thermal expansion (2-6 ppm•K-1). Our results indicated that ANFs are promising nanoscale building blocks for functional ultra-strong and stiff materials potentially extendable to nanocomposites based on other nanoscale fillers.
    ACS Nano 02/2015; 9(3). DOI:10.1021/nn504927e · 12.88 Impact Factor
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    ABSTRACT: The manipulation of the heat flow in a ceramic matrix composite is of great importance in industrial and academic fields. Energy flow, as a typical behavior of heat motion in ceramic surfaces can be confined within specific sites during thermal shock experiments, which weakens the temperature gradient distribution, and hence suppresses the crack propagation. The heat flow can be rationally controlled by the introduction of a nanostructured surface with a diverse forced convection coefficient and heat transfer resistance. Taking inspiration from a nanofin surface, yttria-stabilized zirconia (YSZ) nanostructures were fabricated using the sol-gel method. This bio-inspired coating exhibits a high forced convection coefficient (2.884 times) and high heat transfer resistance (30 times) because of the existence of irregular nanowires arrays and a porous nanostructure. The introduction of the nanostructured coating resulted in the rapid depression of the thermal gradient and stress concentration, and the crack propagation was also effectively suppressed. This sol-gel coating method effectively enhanced the thermal shock resistance of the ceramic materials, and indicates the potential for the application of ceramics in extreme environments.
    Journal of Materials Chemistry A 02/2015; 3(5):2199-2206. DOI:10.1039/C4TA05589F · 7.44 Impact Factor
  • Mingli Yue · Ming Yang · Dan Zhang · Di Xiang · Ying Hou · Jiecai Han
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    ABSTRACT: Nanoscale materials having the size- and shape- dependent interactions with light provide flexible opportunities for harvesting solar energy. Photocatalysts based on semiconductor nanoparticles (NPs) have been the most effective materials for the conversion of light into chemical energy, the efficiency of which can be further enhanced by the incorporation of metallic NPs forming hybrid nanostructures. The structural parameters of not only constituent components but also the resultant hybrid nanostructures are critical for the optimization of photocatalytic performance of composite catalysts. Here we demonstrated the successful size control over ZnO hexagonal pyramids (HPs) for the first time. The smallest HPs showing the best photocatalytic properties were used for further Au attachment. Interestingly, we found that most of the Au NPs preferred to grow on the apexes of the basal plane. Very occasionally, Au NPs at the tip of ZnO HPs can be observed. The role of light in promoting the reduction of gold salt by sodium citrate was also revealed. Quantum mechanical calculations were used to explain the site-specific growth of Au on the surface of ZnO HPs. Enhanced degradation rate over organic dyes were found for Au/ZnO hybrids under both UV and visible light irradiation.
    The Journal of Physical Chemistry C 02/2015; 119(8):150204152655009. DOI:10.1021/jp512570b · 4.77 Impact Factor
  • Jiecai Han · Xiaona Wang · Yunfeng Qiu · Jiaqi Zhu · PingAn Hu
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    ABSTRACT: Transparency in infrared (IR) light region and high conductivity for electromagnetic (EM) shielding performance are contradictory for conventional window materials. It is challenging to explore new class of materials with both IR transmittance and high electrical conductivity. Herein, middle-IR transmittance and EM shielding performance are realized by graphene network fabrics (GNFs). GNFs are fabricated by chemical vapor deposition (CVD) using copper mesh with different geometric construction as sacrificial substrate. The structure of GNFs endows the as-fabricated material high IR transmittance, good electrical conductivity, and EM shielding efficiency. The grid parameter τ with regard to square aperture and wire width is of paramount importance to affect EM shielding performance. The highest EM shielding efficiency is 12.86 dB at 10 GHz with transmittance of 70.85% at 4500 nm. Meanwhile, the highest IR light transmittance is 87.85% with EM shielding efficiency of 4 dB. Based on the experimental and theoretical analysis, the EM shielding efficiency is prominently dependent on microwave absorption.
    Carbon 02/2015; 87. DOI:10.1016/j.carbon.2015.01.057 · 6.20 Impact Factor
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    ABSTRACT: A graphene nanosheet reinforced ZrB2-SiC ceramic composite (GNs/ZrB2-SiC) using graphene oxide (GO) was hot pressed at 1950°C and 30 MPa for 1 h. Raman and XPS analysis showed multilayer GNs structures were successfully introduced into the composite by in situ thermal reduction of GO during the hot pressing process. The homogeneous dispersion of GO guaranteed the uniform distribution of GNs structures in the composite. Mechanical properties such as bending strength, fracture toughness and hardness were studied for the ZrB2-SiC composite with different volumes fraction of GO. The addition of approximately 5 vol% graphene nanosheets improved the fracture toughness of ZrB2-SiC up to 7.32 MPa m0.5, and the strength was also raised to 1055 MPa. The toughening mechanisms were graphene crack bridging and pulling out induced crack deflection in the GNs reinforced composite.
    RSC Advances 01/2015; 5(58):47060-47065. DOI:10.1039/C5RA05922D · 3.84 Impact Factor
  • Xinghong Zhang · Ping Hu · Jiecai Han · Songhe Meng · Shanyi Du
    Chinese Journal 01/2015; 60(3):257. DOI:10.1360/N972014-00456
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    ABSTRACT: To improve the oxidation-resistance of carbon bonded carbon fiber composites (CBCFs), the low density and porous CBCFs modified with ZrB2 and SiC ceramics with density of 0.26, 0.40, 0.61 and 0.77g/cm-3 were prepared by precursor infiltration and pyrolysis method. The pyrolysis behavior of the Zr and B-containing hybrid polymeric precursor was studied. The densification behavior was investigated through the analysis of the microstructures of CBCFs-SiC-ZrB2 (denoted as CSZ) composites with different density. The mechanical properties and thermo-physical properties of CSZ composites were studied. The results show that the incorporation of ZrB2 ceramic coating does not change the anisotropic properties of CBCF composites. The CSZ composite with a density of 0.77 g/cm3 has a continuous ZrB2 ceramic coated layer on the surface of the carbon fibers and exhibits better mechanical properties and antioxidant properties. This investigation reveals that the lightweight ZrB2 and SiC-modified CBCFs possess remarkable thermal properties and can serves as thermal insulation applications at high temperature.
    RSC Advances 09/2014; 4(87). DOI:10.1039/C4RA04089A · 3.84 Impact Factor
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    ABSTRACT: High-quality few-layer-thick graphitic carbon nitride (g-C3N4) nanosheets (NSs) were fabricated by a simple, highly efficient, and rapid method namely, liquid ammonia (LA)-assisted lithiation. Li intercalation occurred in less than half an hour, importantly, the degree of Li intercalation was indicated by the color change of LA solution from deep blue to colorless. The obtained products were carefully investigated by field-emission transmission electron microscopy, field-emission scanning electron microscopy, atomic force microscopy, X-ray powder diffraction, X-ray photoelectron spectroscopy, Raman scattering spectrometry, UV-visible absorption spectrometry, photoluminescence, soft X-ray absorption and nonresonant soft X-ray emission spectroscopy, and X-ray absorption near-edge structure analyses. Because of the lack of high-temperature or high-energy treatment, high-yield few-layer-thick g-C3N4 NSs were produced with trace O2 impurity. Interestingly, while maintaining the similar crystal structure and chemical stoichiometric ratio relative to the parent bulk materials, the surface structure, electronic and optical properties were significantly varied. Moreover, compared to the bulk counterparts, the as-prepared g-C3N4 NSs show clearly enhanced photocatalytic redox activity with respect to both photocatalytic H2 evolution and hydroxyl radical generation. LA-assisted lithiation is a general method and could be easily extended to exfoliate diverse other layered materials such as molybdenum and tungsten sulfides.
    RSC Advances 07/2014; 4(62). DOI:10.1039/C4RA06036A · 3.84 Impact Factor
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    ABSTRACT: A novel plasma exposure technique has been introduced into conventional magnetron sputtering process to enhance the crystallization of indium oxide (In2O3) films at room temperature. The effect of plasma exposure technique with different pulsed DC voltages on the electrical and mechanical properties of In2O3 films was investigated. It is observed that film crystallization can be significantly enhanced when the pulsed DC voltage (|V p|) is higher than |−500 V| (|V p| > |−500 V|). By applying the plasma exposure process, In2O3 films prepared at room temperature with thickness of 135 nm shows low resistivity of 4.11 × 10−4 Ω cm, mobility of 42.1 cm2/Vs, and transmittance over 80 % in the visible range. Compared with the In2O3 films without plasma exposure process, the In2O3 films with plasma exposure show better crystallization and remarkably higher nanohardness. The plasma exposure technique is a useful candidate technique for enhancing film crystallization at low temperature.
    Journal of Materials Science 06/2014; 49(17). DOI:10.1007/s10853-014-8314-0 · 2.37 Impact Factor
  • Yuanchun Liu · Yurong He · Zigui Yuan · Jiaqi Zhu · Jiecai Han
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    ABSTRACT: Hypersonic aircrafts subjected to strong aerodynamic forces and serious aerodynamic heating require a very stringent design of their infrared window. The purpose of this paper is to investigate the thermal shock damage of chemical vapor deposition zinc sulfide (CVD ZnS) infrared window material through finite element analysis and oxygen propane flame experiments. In this paper, a finite element model is developed to simulate the thermal shock behavior of CVD ZnS ablated by an oxygen propane flame. In addition, thermal shock experiments are performed to investigate the thermal shock damage behavior under different conditions. The results show that good agreement between the numerical solutions and the experimental results is achieved. When the heat fluxes are 409.8 kW/m2 and 493.3 kW/m2, the materials have good thermal shock resistance; when the heat flux is 575.9 kW/m2, cracks appeared during the thermal shock resulting in thermal shock damage to the material.
    Journal of Alloys and Compounds 03/2014; 589:101–108. DOI:10.1016/j.jallcom.2013.11.126 · 3.00 Impact Factor
  • Hong Zhu · Ligang Zhang · Jiecai Han · Yumin Zhang
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    ABSTRACT: The dispersion characteristics of Love wave in an isotropic homogeneous half-space covered with a functionally graded layer is investigated. Governing equations for the anti-plane shear wave in the graded layer are derived, and analytical solutions for the displacement and stress field in the layer are given. Moreover, the general dispersion relations of Love wave in both the half-space and the layer are analyzed. For the layer with shear modulus and mass density varying in a parabolic form, the dispersion equations are solved in terms of iteration method. The obtained dispersion curves reveal that there exists a cut-off frequency in the lowest order vibration mode.
    Applied Mathematics and Computation 03/2014; 231:93–99. DOI:10.1016/j.amc.2013.12.167 · 1.55 Impact Factor

Publication Stats

2k Citations
517.11 Total Impact Points


  • 1995–2015
    • Harbin Institute of Technology
      • • School of Astronautics
      • • Center for Composite Materials and Structures (CCMS)
      • • School of Materials Science and Engineering
      • • Department of Physics
      Charbin, Heilongjiang Sheng, China
  • 2009
    • Harbin Institute of Technology Shenzhen Graduate School
      Charbin, Heilongjiang Sheng, China
    • Heilongjiang Institute of Science and Technology
      Charbin, Heilongjiang Sheng, China
  • 2008
    • University Town of Shenzhen
      Shen-ch’üan-shih, Zhejiang Sheng, China
    • University of Windsor
      • Department of Mechanical, Automotive, and Materials Engineering
      Windsor, Ontario, Canada