The research on the resonant characteristics of graphene is essential due to its excellence and vital significance for the future development and application of resonant sensors. Currently, the resonant characteristics of graphene are studied by experimental measurements and theoretical analysis, and the theoretical analysis is composed of the methods based on nano-scale mechanic and on classical mechanics. And the related theoretical researches on graphene are urgent because it is difficult to obtain the resonant characteristics of graphene accurately with experiments. In this paper, research methods, achievements and controversial problems are reviewed, including progress and consensus of the researches on the resonant characteristic of graphene e.g., the experiments of the resonant graphene sensor, the theoretical research methods and its classification, present situation, advantages, disadvantages, as well as the developing trend.

Al₂O₃ buffer layer and Fe₂O₃ catalyst film were deposited on Si wafer successively by atomic layer deposition (ALD). The coated Si wafer was used to grow vertically aligned carbon nanotubes (VACNTs) by water-assisted chemical vapor deposition (WACVD). Results show that catalytically active nanoparticles form in the ALD deposited Fe₂O₃ film after heat-treatment in reduced atmosphere, and the thickness of Fe₂O₃ film is closely related to the size of catalytic nanoparticles and the structure of VACNTs grown. For 1.2 nm-thick Fe₂O₃ film as catalyst layer, the VACNTs have an outer diameter of ~10 nm, wall numbers of ~ 5 and height of ~ 400 μm. Increasing the thickness of Fe₂O₃ film leads to outer diameter and wall number of VACNTs increasing, but the height of which decreasing. It is also observed that VACNTs grows on the side face of Si wafer, which indicates that ALD technique can be useful for VACNTs growth on three-dimensional substrate.

High-efficiency supersonic atmospheric plasma spraying was used to fabricate Ni-C and NiCrAl-BN abradable seal coatings. The erosion wear, corrosion resistance and wear resistance of plasma-sprayed coatings were comparatively studied．Experimental results showed that the libricating phases were homogeneously distributed in the as-sprayed coatings while their average size of the coating was much fine compared with Ni-C coating, and the former also showed higher surface hardness than the latter. Meanwhile, it was found that the erosive mass loss increased with the increase of impingement angle from 30° to 90° and the relative erosion rate of NiCrAl-BN coating was only a half of that of Ni-C coating. Due to the formation of corrosion product around the flake graphite, the corrosion resistance of NiCrAl-BN coating was better than Ni-C coating in dilute hydrochloric acid (1vol%). However, the hydrochloric acid could permeate the NiCrAl-BN coating through the pores, which resulted in the localized corrosion of metal phases. In addition, we also observed that the friction coefficient of NiCrAl-BN coating significantly decreased from room temperature to 400℃ owing to the formation of large-scale self-lubricating film that resulted from the improvement of plasticity and fluidity of BN.

RT base wastewater has high colority, complex components and troubles to recover the TMAOH catalyst in the process of RT base production by nitrobenzene method. Selectively adsorption and separation of by-product from RT base wastewater with magnetic MCM-41 adsorbent was proposed to recover the TMAOH. The magnetic MCM-41 samples prepared were characterized by transmission electron microscopy (TEM), scanning electron microscope (SEM), X-ray diffraction (XRD), N₂ adsorption-desorption vibrating sample magnetometer (VSM). The results showed that the samples had an obvious core-shell structure with an average size of about 200~300 nm in diameter. The N₂ adsorption-desorption results showed that the magnetic MCM-41 exhibited micro-mesoporous structure with specific area of 655 m²/g and pore size distribution of 0.5-4 nm. The as-prepared magnetic MCM-41 displayed typical super paramagnetic property due to the inside component of NiFe₂O₄. The adsorption experiments showed that magnetic MCM-41 selectively adsorbed phenazine, azobenzene and aniline from RT base wastewater. TMAOH aqueous solution could be reused after 5 times adsorptive separation. The synthesized magnetic MCM-41 exhibits high adsorption efficiency and potential applications for the recover for TMAOH catalyst from RT base wastewater with the help of magnetic separation.

Spinel-type transition metal sulfides possess various super physical properties including colossal magnetoresistance (CMR). The research of the mechanism of the CMR effect is of great value for the development of the CMR sulfide materials, whereas the CMR effect of the spinel chrome-based sulfides is unclear up till now. The A_0.05Co_0.95Cr₂S₄ (A=Zn, Ni, Cd, Fe) samples were prepared by solid-state reaction method. Their effects of magnetic and non-magnetic metal elements on crystal structure and magnetic properties of CoCr₂S₄ after doping were studied. XRD measurement shows that the doped A_0.05Co_0.95Cr₂S₄ (A=Zn, Ni, Cd, Fe) samples exhibit pure spinel structure, in which their crystal cell parameters increase proportional to the ionic radius of the doping elements. Magnetoresistance measurement shows that all the samples exhibit giant magnetoresistance effect. Doping weakens the ferromagnetic interaction, which leads to the decrease of T_C of A_0.05Co_0.95Cr₂S₄ (A=Zn, Ni, Cd, Fe). In the low field of 0.01 T, the curves of the zero-field cooling (ZFC) and field cooling (FC) exhibit magnetic irreversible phenomena. All the samples exhibit typical ferrimagnetic hysteresis loops, among which Zn_0.05Co_0.95Cr₂S₄ shows the largest value of coercivity.

T-type zeolite membrances with high permeation performance were successfully synthesized on the low cost macroporous α-Al₂O₃ tubular support by secondary growth from clear solutions. The effects of the concentration of seeds and the membrane crystallization time on the morphology and pervaporation properties of zeolite T membrances. When the molar ration of the synthesis solution was 1SiO₂:0.05Al₂O₃:0.26Na₂O:0.09K₂O: 30H₂O, a high quality T zeolite membrane was obtained at crystallization temperature of 120 ℃ for 16 h, with water flux of 2.96 kg/(m²·h) and separation factor of 6400 for dehydration of IPA aqueous solution by pervaporation at 75℃. XRD pattern and SEM observation suggested that the shortened membrane crystallization time resulted from the secondary nucleation induced by the seeds and the seeds epitaxial growth.

With polyvinyl pyrrolidone (PVP) and sodium dodecyl sulfonate (SDSN) as the template, calcium carbonate hollow microspheres with micro-nano hierarchical structure were successfully synthesized using sodium carbonate and calcium chloride as starting materials through a precipitation reaction method at reaction temperature of 50℃. The products were characterized by scanning electronic microscopy (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD) and other detection methods. The results show that the hollow calcium carbonate microspheres with micro-nano hierarchical structure are about 4-6 μm in diameter. The shell thickness of calcium carbonate hollow microspheres is about 200 nm, which consists of calcium carbonate particles with size about 60 nm. The phase of calcium carbonate hollow microspheres is composed of calcite and vaterite. Excellent dispersibility and spherical morphology of calcium carbonate hollow microspheres can be achieved with addition of 0.1 mol/L SDSN and 0.4 g PVP consequently.

One of the main technical problems in preparation of calcium phosphate/polyurethane (CaP/PU) composite scaffold for bone repair is to obtain a porous structure with uniformly distributed pores. The reason for this is due to the heterogeneous dispersion of the added foaming agents within the composite resulting in the increasing viscosity of polymer precursor during the composite fabrication process. To solve this problem, we report a novel method through incorporation of calcium hydrogen phosphate (DCPD) with polymer phase to achieve a composite system in early period of the synthesis process of CaP/PU composite. The uniformly distributed crystal water from DCPD can be released when temperature reaches above 75 ℃ and serve as foaming agents to react with isocyanate group in the PU and generate CO₂ gas. The generation of gas leads to a self-foaming process and consequently induces CaP/PU composite to form a porous scaffold. Scanning electron microscopy (SEM) observations show that CaP/PU composite scaffolds with uniform porous structure, high porosity and interconnectivity were obtained at 90 ℃. The mechanical strength can be doubled by re-curing treatment for the scaffold at 110 ℃ for 24 h. The resulting CaP/PU composite scaffolds with uniformly porous structure, high porosity and interconnectivity have shown potential applications in bone tissue engineering. Moreover, this simple and efficient method may provide new approaches for the preparation of polyurethane- based porous scaffolds.

Hydroxyapatite fiber with high crystallinity was successfully fabricated by hydrothermal homogeneous precipitation synthesis with Ca(NO₃)₂·4H₂O and (NH₄)₂HPO₄ as precursors. Effects of the surfactants include cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS) and polyethylene glycol (PEG), and different amounts of them on the morphology and phase composition of the obtained products were investigated. Results show that the products obtained by using the three surfactants are all hydroxyapatite with minor CaCO₃ in some samples. The addition of both CTAB and SDS inhibits the growth of the fibers, leading to the coexistence of fibers and spherical aggregates. However, the addition of PEG can promote the growth of fibers to some extent.

ZnO/ZnAl₂O₄ nanocomposites were successfully synthetized by a facile one-pot hydrothermal process. CuS, CdS and Bi₂S₃ were loaded on the ZnO/ZnAl₂O₄ by an impregnation process to investigate their photocatalytic activities under simulated sunlight irradiation. The as-prepared samples were characterized by XRD, SEM, TEM, BET and FL techniques. Meanwhile, photocatalytic reduction of CO₂ from water over the samples was explored using NaOH and Na₂SO₃ as sacrificial reagents. The effects of the type and the amount of sulfides on photocatalytic reduction efficiency were investigated. The results indicated that Bi₂S₃-loading lowered down the photocatalytic activity of ZnO/ZnAl₂O₄, while CuS or CdS loading enhanced the photocatalytic activity. After ZnO/ZnAl₂O₄ loaded with 1wt% CuS, the maximum yield of 8.21 mmol/g_cat methanol within 6 h was obtained, which increased by up to 3.2 times as compared to ZnO/ZnAl₂O₄ under the same conditions. The photocatalytic mechanism of the as-prepared CuS/ZnO/ZnAl₂O₄ were preliminarily discussed.

Functional TiO₂ films were prepared by using a facile one-step Pechini Sol-Gel method. The intrinsical contribution mechanism of film thickness to the photo-to-electric performance of DSSC was explored with analysis of interfacial charge recombination effects, on which, the characteristics of DSSC were optimized via film thickness controlling. The influence of TiO₂ film thickness on dye absorption, charge recombination process and photovoltaic performance of DSSC were by UV-Vis, electrochemical impedance spectroscopy and I-V test under dark condition, respectively. The results show that as TiO₂ film thickness increases, the light harvesting efficiency and photocurrent of DSSC increase, which were induced by the enhancement of dye absorption. However, the photovoltage decreases gradually with the increaese of electron recombination probability. As an increase, combination of the positive and negative effects above enables the Pechini-type DSSC efficiency first increase and then decline, with an optimum efficiency of 7.75% at the film thickness of 10.7 μm, in contrast to 6.5% of the routine method.

The nitrogen-doped amorphous indium-zinc-oxide thin film transistors with double channel layers (a-IZO/IZON-TFTs) were fabricated by RF magnetron sputtering of IZO target on the thermal oxidized p-type Si substrate. Influence of the double channel layers on the electrical performance and thermal stability of the devices were investigated. It is found that a-IZO/IZON-TFTs have high field effect mobility of 23.26 cm²/(V•s) and more positively shifted threshold voltage than that of a-IZO-TFTs. This is ascribed to the doped nitrogen which can help reduce oxygen vacancy in the channel layer, suppress carrier concentration and make the devices have a better threshold voltage. Meanwhile, employing a-IZO thin film can avoid the sharp drop of field effect mobility and drain on current caused by nitrogen doping on a-IZON layer, leading to promoting I_on/I_off ratio effectively. Besides, according to the transfer characteristics measured at temperatures from 298 K to 423 K, devices with a-IZO/IZON double layers have superior performance and thermal stability to TFTs of single channel layer, which can be ascribed to the protective effect of a-IZON thin film on the channel layers. The doped nitrogen can reduce the adsorption/desorption reaction of oxygen molecules on the back channel layer, leading to a significant improvement on thermal stability of the devices.

SnSe material is one of the most promising state-of-art thermoelectric materials. The polycrystalline Ag-doped Sn_1-xAg_xSe (0.005≤x≤0.03) bulks were prepared by mechanical alloying and spark plasma sintering technique, and the composition, microstructure and thermoelectric properties were systematically studied by XRD, SEM and thermoelectric performance measurement. XRD results show that single-phase orthorhombic SnSe-based compounds can be prepared with small amount of Ag-doping (0.005≤x≤0.01), but with Ag doping amount increasing, small quantity of secondary phase, SnAgSe₂, can be detected in the matrix. The carrier concentration and overall electrical properties (power factor) are significantly enhanced as a result of Ag doping. The power factor of Sn_0.98Ag_0.02Se increases up to 0.495×10^-3 W/(m·K²), which is about 36% higher than that of SnSe material. Although the thermal conductivity increases slightly, the dimensionless figure of merit, ZT is still optimized for the Ag-doped samples. Sn_0.98Ag_0.02Se bulk shows optimal ZT value and the highest ZT of 0.82 is obtained at 823 K, which is the highest value reported for the polycrystalline SnSe-based thermoelectric materials.

The cathode with high performance is a key factor to improve the electrochemical properties of SOFC. In order to increase the electrochemical properties and reduce the polarization impedance of the cathode, LSCF (La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ)-GDC(10GDC) porous cathode was dipped by the LSM(La_0.85Sr_0.15MnO₃) sol which was prepared via Pechini method, and then the LSM-LSCF-GDC three-phase composite cathode was constituted after calcinations. To improve the efficiency of impregnation, LSM sol with different pH was used to impregnate. The pH of LSM sol was the most important factor which affected impregnated effect and amount of impregnation. The complex colloid particles was negatively charged when LSM sol appeared weak alkaline. Meanwhile, a large number of negative charges was existing on LSCF-GDC hole inner wall, indicaing the repelling force was the main force between the colloid particles and hole wall, helpful to the LSM colloid particles impregnate into the inside hole of the cathode. The results showed that the generated LSM nano particles could be evenly distributed on the inner wall of the cathode skeleton when the pH of LSM sol was equal to 8.0. Cathode polarization impedance increased firstly and then reduced with the increase of impregnation times. The composite cathode impregnated in LSM sol for 3 times attained the minimum polarization impedance of 0.16 Ω•cm² (700℃in the air). The maximum power densities of impregnated and un-impregnated cells were 0.645 W/cm² and 0.503 W/cm², respectively, at the working temperature of 700℃, using 3% H₂+H₂O as fuel and air as oxidizing gas.

NiFe₂O₄ ceramic inert anode for aluminum electrolysis, strengthened by adding NiFe₂O₄ nanopowder, was prepared via powder metallurgy method. The effects of NiFe₂O₄ nanopowder content on sintering behavior and properties of NiFe₂O₄ ceramic inert anode were studied. Linear shrinkage and scanning electron microscope (SEM) were employed to characterize the sintering property and microstructure. The results show that the sintering shrinkage degree increases gradually as increase of NiFe₂O₄ nanopowder content, while the sintering temperature and apparent activation energy of initial stage of sintering decrease. When nanopowder content is 40%, the sharp sintering shrinkage begins from 900℃ and the apparent activation energy of initial stage of sintering drops to 291.43 kJ/mol. Volume density, bending strength and fracture toughness are enhanced firstly and then decreased with the increase of nanopowder content, while the porosity and static corrosion rate display opposite tendency. The maximum value of fracture toughness is 3.12 MPa•m^1/2 with nanopowder content of 30%, which is 2.14 times that of without adding nanopowder. The toughening effect is realized by the elevated fracture surface energy, which is attributed to the enhanced grain boundary cohesive bond and the reduced porosity with addition of NiFe₂O₄ nanopowder.

Metal-supported solid oxide fuel cells (MS-SOFCs) have many advantages like low materials cost, excellent structural stability and high tolerance toward rapid thermal cycling over the traditional all ceramic SOFCs. To facilitate the commercialization of SOFCs, an all symmetrical MS-SOFC with the structure of Ce_0.8Sm_0.2O_2-δ (SDC)-430L anode/Zr_0.88Sc_0.22Ce_0.01O_2.12(SSZ) electrolyte/SDC-430L cathode was developed by a tape casting- sintering-infiltration method. When measured in humidified hydrogen fuel and air oxidant, the maximum power densities (MPD) of the fuel cell are 220, 250 and 280 mW/cm² at 600, 650 and 700℃, respectively. Electrochemical impedance spectra measurement shows that the cell performances are primarily dominated by polarization resistances derived from the SDC-430L electrodes. The pure ohmic resistances are 0.16, 0.21 and 0.29 Ω•cm² and the polarization resistances are 0.67, 0.90 and 1.22 Ω•cm² at 700, 650 and 600℃, respectively. Compared with that of the anode, polarization resistance of cathode is much higher. When measured at 650℃, polarization resistances of the symmetrical SDC-430L cell are 0.23 and 1.92 Ω•cm² in 3%H₂O-97%H₂ and air, respectively. Further optimizing the cell structure (e.g., applying a finer 430L backbone) and the catalyst materials (e.g., Ag, Pt containing composite materials) may enhance the electrochemical performances of such MS-SOFC.

The effect of washing on electrochemical properties of Ni-rich layered cathode LiNi_0.8Co_0.15Al_0.05O₂ powder is widely known, but few literatures have reported thoroughly. Primitive LiNi_0.8Co_0.15Al_0.05O₂ powders processed by deionized water and heat-treatment at different temperatures in a paralleling time was explored for the first time. Significant changes of structure, morphology and electrochemical charge/discharge property of the LiNi_0.8Co_0.15Al_0.05O₂ cathode were detected comprehensively. Mechanism of washing and heat-treatment on the structure and electrochemical charge/discharge property and the rate performance were studied. XRD patterns show the I₍₀₀₃₎/I₍₁₀₄₎ value of LiNi_0.8Co_0.15Al_0.05O₂ powders decreases and the volume turns smaller after being washed and heat-treated. FT-IR spectra confirm the existence of lithium carbonate, and nickel compounds and their relative changes in the LiNi_0.8Co_0.15Al_0.05O₂ powders. The specific capacity and rate performance of the LiNi_0.8Co_0.15Al_0.05O₂ powders were carried out before and after washing and heat-treatment. The capacities of primitive sample and treated samples remain 88.87%, 87.21%, 85.43% and 87.80% after 30 cycles, respectively.

Al₂O₃ thin films with or without HfO₂ interlayer between Al₂O₃ and substrate were deposited on MgF₂ substrates by electron-beam evaporation technique. The as-deposited thin films were then annealed at 600℃ for 1 h to promote crystallization. The microstructure, IR transmittance and mechanical properties of the as-deposited and annealed samples were investigated by field emission scanning electron microscopy (FE-SEM), grazing incidence X-ray diffraction (GIXRD), Fourier Transform Infrared (FTIR) spectrometer, nanoindentation, and scratch tests, respectively. FE-SEM results show that a new branch-like layer is generated in annealed HfO₂/Al₂O₃ double-layer thin films. The hardness of the newly formed layer is considered to be larger than 17.5 GPa. Because of the high hardness of the new layer, the MgF₂ substrate can be protected from being drown out during scratch test. From GIXRD patterns, Al₂O₃ still remains amorphous while HfO₂ interlayer transforms from amorphous to monoclinic phase after annealing process. It could be deduced that it is the phase transformation of HfO₂ interlayer that promotes the formation of the harder branch-like layer.