Graphene has attracted much interest in recent years due to its unique and outstanding properties. Different routes to prepare graphene have been developed and achieved. Preparation methods of graphene used in recent years are intensively introduced, including micromechanical cleavage, chemical vapor deposition, liquid/gas- phase-based exfoliation of graphite, epitaxial growth on an insulator, chemical reduction of exfoliated graphene oxide, etc. And their advantages and shortcomings are further discussed in detail. The preparations of graphene are also prospected.

CaZr_1-xIn_xO_3-α(x=0, 0.05, 0.10, 0.15) ceramics were synthesized by using solid state reaction method at 1400℃, and then sintered at 1550℃ for 10 h in air. The XRD results show that there exist CaZrO₃ and infinitesimal CaIn₂O₄ phases. The AC impedance spectra of the sintered CaZr_1-xIn_xO_3-α were measured in the temperature range from 600℃ to 850℃ in argon atmosphere containing water vapor. The relation between conductivity and temperature was obtained, as well as the activation energy. At 800℃, the conductivity of CaZr_1-xIn_xO_3-α is 4.64×10^-7 S/cm (x=0), 3.06×10^-4 S/cm (x=0.05), 3.89×10^-4 S/cm (x=0.1), 3.93×10^-4 S/cm (x=0.15), respectively. The results show that the conductivities of the samples improves remarkably, the activation energy decreases rapidly with In doping contents increasing. The conductivities slightly increase with the increase of In doping contents (x>0.1), they increases greatly with the increase of temperature. The relationship between In doping contents and conductivity are deduced.

A novel type of SiO₂@TiO₂ core-shell particles were fabricated as pigments for high-temperature thermal insulation coatings using a Sol-Gel method. TEM images of SiO₂@TiO₂ core-shell particles indicated that TiO₂ shell with a thickness about 50 nm was deposited well on the surface of SiO₂ particles. The thermal insulation properties of the products obtained were characterized by a developed apparatus in the temperature range from 1300℃ to 1500℃. The results show that, using SiO₂@TiO₂ particles as a radiant barrier, the heat flux from radiation sources is successfully reduced by about 50% and the temperature difference reaches 260℃ when radiation heater temperature is 1500℃. The effectiveness of SiO₂@TiO₂ core-shell particles on high-temperature thermal insulation is obvious. The work suggests that SiO₂@TiO₂ core-shell particles are very promising pigments for high-temperature thermal insulation coatings.

Zinc ion battery, a new type of aqueous secondary batteries proposed in recent years, can deliver high energy and high power density. Meanwhile, safe and efficient discharge processes, cheap and nontoxic electrode materials, and easy fabrication are the advantage of Zinc ion battery, showing great practical value and developmental prospects in the field of scale energy storage. In this paper, the development and exploration of aqueous zinc ion battery are reviewed. Also the advantages and challenges of the zinc anode are summarized. Moreover, this paper analyzed the electrochemical properties and reaction mechanism specifically. In addition, the development of cathode materials is predicted by analyzing the insertion and extraction of multivalent ions.

The Wolframite ZnWO₄ nanocrystallites were prepared by a facile, template-free microwave hydrothermal method using Na₂WO₄·2H₂O and Zn(COOCH₃)2·2H₂O as starting materials. The phase, morphology and optical properties of as-prepared samples were characterized by X-ray Diffraction (XRD), Transmission Electron Microscope (TEM), UV-Vis absorption spectra (UV-Vis) and photoluminescence spectroscopy (PL). Results indicate that ZnWO4 nanocrystallites have a preferential orientation growth along the (100) planes, and the morphology of ZnWO₄ nanocrystallites change into rodlike structure with the increase of microwave hydrothermal time. An intense blue PL emission with a 460 nm wavelength is observed when the as-prepared ZnWO₄ nanocrystallites are excited by a 295 nm wavelength, and they show a strong absorption in the ultraviolet region. The ZnWO₄ nanocrystallites whose orientation degree of (100) planes is 0.24 with the particle sizes of 50–60 nm show the best photocatalytic properties.

A newly structured tandem dye-sensitized solar cell (tandem DSC) based on stainless mesh was introduced, in which the electrode constituted a first TiO₂ film on TCO and a second TiO₂ film on stainless mesh. Negative interaction between different dyes in this structure is less than that by normal method of cocktail-dyes dipping. The application of stainless mesh here reduces the loss of incident light, solves the problem of electronic connection between two different TiO₂ films, as well as improves electron transport and collection. This tandem cell achieved a power conversion efficiency of 1.96% with short circuit current density of 8.4mA/cm². Compared with normal mono-layer DSC with similar cell thickness, efficiency was improved about 62% by this tandem structure. Electrochemical impedance spectroscope (EIS) was used to analyze the electron transport in tandem DSC, and an equivalent circuit for tandem DSC was also proposed here. Meanwhile, the increased cell thickness and electron recombination on the surface of the stainless mesh have obvious influence on the photovoltaic performance.

High quality iron-based superconductors of Sm_0.85Nd_0.15FeAsO_0.85F_0.15 were reproducibly synthesized from highly reactive powders prepared by mechanical alloying method. The samples show T_c around 51 K, with an upper critical field (H_c2) up to 377 T determined from WHH formula, which is much higher than those found in the samples prepared from conventional solid state reactions (< 200 T). The high H_c2 is closely correlated with its microstructure. It is proposed that the mechanically alloyed raw materials contained high densities of lattice distortions, which were partially maintained during rapid heating and low temperature sintering, thus contributing to flux pinning in the final fine-grain ceramics.

Microstructure engineering is an effective avenue for tuning the thermal and electrical transports to op-timize thermoelectric (TE) properties. Thermoelectric composites with nano-particle dispersion have been success-fully developed by using extrinsic or in-situ formation methods. The lattice thermal conductivity can be depressed by the scattering effects of nano particles to the medium-long-wavelength phonons. The enhanced electron density of states at the Fermi level and the carrier filtering effects caused by the nano-sized grain boundary are also positive for enhancing Seebeck coefficients. The mixing, in-situ oxidation and phase-separation precipitation process supply possibility to realize the nano-particle dispersed structure for different material systems. This paper reviews the re-cent progress of the research on nano-structured and nano-composite thermoelectric materials. The effects of the nano-dispersion on the electrical and thermal transports will be also discussed.

Sodium-montmorillonite (Na⁺-MMT) was intercalation modified with octadecyl trimethyl ammonium chloride (OTAC) in aqueous suspension via an ion exchange mechanism. Fourier transform infrared spectroscopy (FTIR) study indicates that OTAC is successfully intercalated into Na⁺-MMT layers and/or adsorbed on the surface of Na⁺-MMT. X-ray diffraction (XRD) analysis revealed that the interlayer spacing of the Na⁺-MMT was extended with the content of OTAC increasing, and the maximum spacing can reach about 3.80 nm. Results of scanning electron microscopy (SEM) analysis reveals the morphologies change from soherical-like particles to high-aspect ratio flakes after modification. Different configurations of OTA⁺ chains within MMT interlayer are proposed based on the above analysis. The results of contact angle and the dispersion analysis show that the surface wettability of Na⁺-MMT is converted from hydrophilic to organophilic.

Lead magnesium niobate-lead titanate (PMN-PT) ferroelectric thin films with composition near the morphotropic phase boundary (MPB) were deposited on Si substrate by oxygen plasma assisted pulsed laser deposition (PLD). Highly (001)-oriented PMN-PT thin films with lower oxygen defect and higher crystalline property were obtained. The results show that the microstructure and electrical properties of PMN-PT thin films strongly depend on the partial pressure and the activity of oxygen in the deposition process. With the use of oxygen plasma, the dielectric constant of the PMN-PT thin film is increased from 1484 to 3012, the remnant polarization (2P_r) changes from 18 μC/cm2 to 38 μC/cm².

Grain oriented K_0.45Na_0.55NbO₃ (KNN) lead-free piezoceramics with sintering aid K₄CuNb₈O₂₃ (KCN) were fabricated by screen-printing technique, using plate-like NaNbO₃ as templates. The plate-like NaNbO₃ template particles were synthesized from bismuth layer-structured Bi_2.5Na_3.5Nb₅O₁₈ precursors by the topochemical micro-crystal conversion method. The textured KNN ceramics showed brick-wall-like grains which aligned parallel to the screen-printing direction. The screen-printed KNN ceramics possessed both a high grain orientation (Lotgering factor f=95%) and a relative high density (92% of theoretical density). The orientation degree and electrical properties of textured (K_0.45Na_0.55)NbO₃ ceramics exhibited anisotropic feature in the parallel (sp//) and perpendicular (sp?) plane. Compared with the random oriented ceramics with same composition, the dielectric constant ε_r, piezoelectric constant d₃₃, and electromechanical coupling coefficient k_p were increased by about 75%, 44% and 42% in sp// plane, respectively, and about 35%, 30% and 35% in sp? plane, respectively. Screen-printing is a simple and effective method for the fabrication of grain oriented lead-free piezoelectric ceramics.

Yttria stabilized zirconia coatings were deposited using two different sets of parameters (N1, N2 coating). The microstructure features, such as total porosity and large porosity, were quantified by means of scanning electron microscope and image analysis. The three-dimensional distribution of microcracks and segmentation cracks was successfully revealed by the X-ray microscopy in the scanning electron microscope with three-dimensional microtomography capability. So the relationship between microstructure and thermal conductivity was found. At room temperature, thermal conductivity of N2 was lower than that of N1 due to larger pores and microcracks. At 1000℃ thermal conductivity of N1 was lower for the sintering of microcracks. The segmentation cracks formed by the propagation of microcracks could effectively reduce the thermal conductivity at high temperature.

Dielectric materials based on short carbon fiber (Csf) dispersed inside epoxy resin (EP) matrix composites were prepared. The complex permittivity of two types of distributions over the frequency range from 2.6 GHz to 8.2 GHz was reported. The effects of orientation with different content and length of carbon fibers on dielectric properties were investigated. It is found that axial permittivity of carbon fibers is several times larger than their radial permittivity. The real and imaginary parts of complex permittivity increase gradually with increasing the Csf contents in the composites, and the fiber length also affects the anisotropic property greatly. The two layered transmission line model is used to explain the phenomena.

Porous SnO₂ agglomerates with crystalline pore walls were obtained by employing CTAB and trimethyl phosphate (TMP) as molecular co-templates via hydrothermal method. Tin (IV) chloride dihydrate was used as the inorganic precursor at high molar ratio of surfactant/Sn⁴⁺. The resulting samples were characterized by SEM, (HR)TEM, XRD, thermal analysis and nitrogen adsorption-desorption to examine the structural and morphological characters. The results indicate that the addition of small co-template TMP can facilitate the assembling of tin ions near the CTAB micelles, which can increase the specific surface area and improve the thermal stability of the resulted sample. The electrochemical properties of porous SnO₂ as the anode materials of lithium-ion battery (LIB) are further investigated by using galvanostatic method. The porous SnO₂ calcined at 300℃ displays a much higher reversible capacity of 962.4 mAh/g, which can be ascribed to the incomplete combustion of the organic materials and the unique nanostructure itself. The addition of bigger counter ions with large electric negativity might give an alternative approach to improve the properties of porous metal oxides synthesized by soft template method.

Graphene has recently attracted much interest in material field due to its unique two-dimensional structure and outstanding properties. Various preparation methods of graphene are briefly compared. The physical and mechanical properties of graphene are then introduced. Graphene-based composite becomes one of the most important research frontiers in the application of graphene. A comprehensive review is presented to introduce the latest progress of the graphene related composites, including graphene-polymer composites and graphene-based inorganic nanocomposites, especially introducing the fabrication methods and outstanding performances of the bulk metal-matrix/ graphene composites.

ZnO nanorod arrays (ZNRs) were prepared on the tin-doped indium oxide polyethylene terephthalate (ITO-PET) by hydrothermal method under different conditions. Morphology of ZNRs was characterized by some quantitative parameters such as the diameter and length of nanorod and the density of rods. All these parameters were adjusted by changing the reaction conditions. Two important reaction conditions including reaction time and precursor concentration are discussed separately. It is demonstrated that the precursor concentration has great influence on the aspect ratio of nanorod. Flexible substrates with ZNRs are used as the novel photoanode of flexible dye-sensitized solar cells (DSCs). The aspect ratio of nanorod has major influence on the performance of flexible DSCs. The performance of flexible DSCs is improved by controlling the reaction conditions.

Eu³⁺-doped Bi₄Si₃O₁₂ phosphors were synthesized by the conventional solid state reaction. X-ray diffraction analysis confirmed the formation of Bi₄Si₃O₁₂: Eu3+. The excitation spectra of Eu3+-doped Bi₄Si₃O₁₂ show an intense broad band with maximum at 265 nm related to Eu³⁺→O^2- charge transfer transition. Photoluminescence spectra indicate that the phosphor emits strong red light centered at 614 nm under UV light excitation. Due to high emission intensity and a good excitation profile, the Eu³⁺-doped Bi₄Si₃O₁₂ phosphor may be a promising candidate in solid state lighting applications.

Pure (K_0.5Na_0.5)NbO₃ and 0.98(K_0.5Na_0.5)NbO₃-0.02LaFeO₃ ceramics (abbreviated as KNN and 0.98KNN-0.02LF, respectively) were prepared by a solid state reaction approach, and their crystal structure, dielectric and ferroelectric properties were investigated. Pure KNN and 0.98KNN-0.02LF ceramics are the orthorhombic structure and pseudo-cubic perovskite structure, respectively. Dielectric measurements revealed that the dielectric permittivity curves of 0.98KNN-0.02LF ceramics present two anomalies compared with pure KNN: (i) The orthorhombic- tetragonal transition (T_O-T) and the tetragonal-cubic transition (T_T-C) shifts to lower temperatures. (ii) The phase transition temperature range around the temperature of the maximum dielectric permittivity (T_m) becomes more and more broad. In addition, 0.98KNN-0.02LF ceramics exhibited a very stable temperature dependence of dielectric permittivity with permittivity maximum near 2000 and dielectric loss less than 4% in the temperature range of 0–400℃. The relaxation behavior of the 0.98KNN-0.02LF ceramics is interpreted in terms of polar nanoregions (PNRs) caused by cations disorder. The P-E hysteresis loops further confirms the relaxor behavior in 0.98KNN-0.02LF ceramics.

Sr₄Al₁₄O₂₅:(Eu,Dy) phosphor materials were prepared by solid state reaction. The dependence of long persistent luminescence from Sr₄Al₁₄O₂₅:(Eu²⁺, Dy³⁺) on the amounts of H₃BO₃, the solid state reaction temperature, and the contents of Eu were studied. It was found that the addition of H₃BO₃ as the flux agent was critical for the formation of the blue-green emitting Sr₄Al₁₄O₂₅ phase. Sr₄Al₁₄O₂₅ phosphors with persistent luminescence of 490 nm and afterglow time more than 24 h was obtained for the sample prepared at 1400℃ with the doping amounts of H₃BO₃ of 10at% and Eu/Al atomic ratio of 0.03, respectively. Furthermore, the dependence of persistent luminescence intensity on Eu content indicates that the persistent luminescence process is mainly controlled by the electron transition rate from deep traps to Eu²⁺ levels.

Highly dispersed gold nanoparticles incorporated mesoporous zirconia thin films were synthesized through an easy deposition-precipitation method using urea as precipitator. The resultant composite thin films presented an enhanced off-resonant third-order optical nonlinear susceptibility of 10^-10 esu measured by Z-scan technique at 1064 nm. The enhanced optical nonlinearity of the composite thin films was attributed to the high dispersion of the gold nanoparticles and the high linear refractive index of the zirconia matrix.

3D meshes of TiO₂ were fabricated by direct writing and subsequently sintered at 1150℃ for 2 h in an air atmosphere for photocatalytic degradation (PCD) of methylene blue(MB) solution. The crystal structure and morphology of the samples were determined by X-ray diffraction(XRD) and scanning electron microscope(SEM). PCD properties of the sintered meshes were obtained in an ultraviolet-visible light spectrophotometer, and were found to be better than that of cylindrical samples with the same weight. Three kinds of mesh structures were designed, sintered and measured. The results show that reasonable design could cause significant enhancement in the PCD activity by more than 60%. This enhancement could be attributed to irradiation absorption increment, which was caused by structure design of photocatalyst.

Mesoporous carbon CMK-3 was synthesized by using SBA-15 silica mesoporous as hard template and characterized through nitrogen adsorption/desorption and low angle X-ray diffraction. As-prepared material with large pores and high surface area was used to remove Orange G dye from aqueous solution. Adsorption experiments were carried out as batch studies at variety of contact times, pH, initial dye concentrations, temperatures and salt concentrations. Langmuir and Freundlich isotherm models were employed to simulate the equilibrium data of anionic dye. It was found that the equilibrium data were well represented by the Langmuir isotherm, yielding maximum monolayer adsorption capacity of 189 mg/g. Experimental data were analyzed using pseudo-first order and pseudo-second order kinetic models and obtained results indicated that kinetics followed a pseudo-second order equation.

The nanocrystalline and amorphous CeMg₁₂+100wt%Ni+Ywt%TiF₃(Y=0, 3, 5) alloy samples were synthesized by ball milling technology. The infulence of TiF₃ on microstructure and electrochemical properties of milling alloys were investigated. The electrochemical performance of prepared alloy samples was studied through discharge capacity, cycle stability and electrochemical kinetic, meantime. By using electrochemical PCT (pressure-concentration- isotherm) curves the change law of electrochemical performance of ball-milled alloys was further explained from the view of thermodynamics. The result showed that TiF₃ was helpful for enhancing the nanocrytstalline and glass forming ability of milled CeMg₁₂+100wt%Ni+Ywt%TiF₃(Y=0, 3, 5) hydrogen storage alloys, improving the electrochemical and kinetic properties. On the other hand, in milling process, addition of TiF₃ reduced the hot stability of alloy hydride to some degree, accelerating the electrochemical dehydriding reaction.

Bismuth telluride thin films with layered nanostructure have been fabricated by radio frequency (RF) magnetron sputtering. Thin films were deposited at various substrate temperatures and durations with a single Bi₂Te₃ target. The microstructures and chemical compositions of these films were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive spectroscope (EDS). Electrical transport property and Seebeck coefficient were measured on these thin films. The results show that substrate temperature is a key factor on the microstructure and transport property of bismuth telluride thin films. High temperature is beneficial for the formation of layered nanostructure and the enhancement of power factor. The highest power factor was obtained on the thin film deposited at 400℃. However, Te deficiency was observed in these thin films. Thus thermoelectric property would be further enhanced by optimizing composition of these thin films.

Ultra-thin absorbers at low frequency bands composed of two traditional microwave absorbing material (MAM) rubber plates and fractal frequency selective surface (FSS) were designed. The absorbing properties of composite absorbers of different arrangement of MAM and FSS were investigated in detail in L and S bands. Two traditional MAM rubber plates and fractal FSS layers were fabricated for producing the multilayer microwave absorber (MMA) samples by using vulcanizing and laser etching methods, respectively. The reflectivity of MMA samples were measured by the NRL-arch testing systems. It is found that introducing FSS layers into the traditional MAM plates indeed could strengthen the absorbing properties of MMA samples at low frequencies. Moreover, after proposing double FSS layers in a proper arrangement, the MMA sample with the thickness of only 1.8 mm could obtain peak value of –9.35 dB and the reflectivity value of –3.49 dB at 1 GHz, respectively. As a result, the introduction of fractal FSS layers could provide another way to develop the absorbing properties at low frequency bands.

The nanosized fluorhydroxyapatite (FHA) were synthesized by an aqueous precipitation method. The effects of synthesis temperature, molar ratio of NH4F to Ca(NO₃)₂·4H₂O in the initial reagents[n(F^–)/n(Ca²⁺)] and the pH value on the fluoride substitution were investigated. The phase composition and the change of crystal structure were characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscope (FT-IR). The morphology of FHA was observed by Transmission electron microscope (TEM). The results show that crystal lattice parameters and bond energy make changes by incorporation of F– ion in the structure. The size and aspect ratio of FHA crystals increase as the precipitation temperature and fluoride concentration. The phase composition of FHA is mainly controlled by the pH value. Considering the possibility of a competition between OH^– and F^– for occupation of the OH–site, high pH value isn’t conductive to the fluoride substitution.

The spray pyrolysis technique is a wonderful method in material science. It possesses many advantages, such as low processing temperature, high homogeneity and purity of products, and so on. The key challenges of spray pyrolysis are control over the morphology and composition of product particles. It has been widely applied in the past few years. In this paper, the spray pyrolysis technique and the applications in production of ceramic powders, films, and fibers were briefly reviewed.

Ba_0.9175Ca_0.08Nd_0.0025(Zr_0.18Ti_0.8175-xY_xMn_0.0025)O₃(BCZT-Y, x=0, 0.5mol%, 0.75mol%, 1.0mol%, 1.5mol%, 2.0mol%) ferroelectric ceramics was prepared by a solid phase reaction. The influence of Y³⁺ doping on the structure and dielectric properties of BCZT-Y ceramics was investigated. Results showed that with the Y³⁺ contents increasing, Y³⁺ ion substitution can be almost incorporated into the Ti⁴⁺ site, and the density of BCZT-Y ceramics increased from 4.029 g/cm³ to 6.058 g/cm³. The Curie temperature was shifted to lower temperature, and the ε_r-T peak was decreased and broaden. The ferroelectric relaxor characteristics were obtained while Y³⁺ ion content was further increased, which were consistent with the Lorenz-type formula fitting. It was found that the area of ferroelectric hysteresis loop became narrow and slant, the remnant polarization (P_r) and coercive field (E_c) reduced with the increase of Y³⁺ content.

Nanocrystalline NiFe₂O₄ powders were synthesized by citrate. Nitrate SolGel auto combustion method at room temperature. Various xerogels were obtained by adding different amounts of ammonia into precursor solution. The corresponding auto combustion powders were prepared through subsequent auto combustion process. The variation regularity of crystallinity of auto combustion powders, properties and thermal decomposition process of xerogel were investigated by XRD, TEM, IR and TG-DTA techniques. The mechanism of auto combustion method was further studied. The results indicate that auto combustion powders are mainly composed of NiFe₂O₄ phase with small amout impurity phase of α-Fe₂O₃ and FeNi3. The crystallinity of auto combustion powders are enhanced with increasing the amount of ammonia. The xerogel contains amorphous phase and NH₄NO₃ crystallization phase. The amount of ammonia exerts appreciable effects on the quantity of NH₄NO₃ and properties of xerogel. The mechanism of auto combustion is a chain reaction which is formed by mutual promotion of NH₄NO₃ decomposition and citric acid combustion.

Graphene has attracted much attention in fields such as physics, chemistry, and materials science, because of its unique properties and potential applications. Interests in graphene applications in solar cells have been motivated to meet the demand of improving the photovoltaic performance. Graphene applications in solar cells, such as graphene based transparent conducting electrodes, photoanodes, and accepter materials, are reviewed systematically. The further prospects and improvement of graphene applications are also discussed.

The title new compound Ce₅AgBi₃ was synthesized by arc melting method followed by annealing. The crystal structure refined using Rietveld method and X-ray powder diffraction data shows that it is similar to Hf₅CuSn₃ with space group p63/mcm (No.193). The unit cell parameters are a=b=9.7163(3)A, c=6.6228(2)A and V=541.47(5)A³. The structure is characterized by layers of Ce-Bi net formed by Ce and Bi at 6g position. Ce at 4f position and Ag at 2d position are separated in those two different kinds of Ce-Bi hexagon tunnels along c axes, respectively. Magnetism and specific heat property of Ce₅AgBi₃ are measured using PPMS. Ce₅AgBi₃ is antiferromagnetism and complies with Curie-Weiss law above T_N=3.8K. The calculated moment is 2.67μ_B, fitted well with μ_eff of Ce^3+，which means that the magnetism of Ce₅AgBi₃ is mainly offered by Ce^3+.

A novel method of microwave irradiation assisted thermal decomposition to prepare metal oxide electrodes was proposed in this paper. The electrodes were prepared by the microwave irradiation and the dip-coating method, respectively. The as-prepared electrodes were characterized with scanning electron microscope (SEM), X-Ray Diffraction (XRD), linear sweep voltammetry and accelerated life test to find out the difference between the novel method and the traditional one. Wastewater degradation experiment was also carried out using the electrodes prepared with the above mentioned approaches, with Acid Red G as target pollutant. In comparison with the traditional dip-coating thermal decomposition method, the microwave irradiation method takes less time (2 h) and less complicated operation procedure. The results demonstrate that the electrode prepared by the novel microwave method is better in surface morphology, crystalline, stability and electro-catalytic property, comparing with that prepared by traditional method.

NaCu₃Ti₃NbO₁₂ and NaCu₃Ti₃SbO₁₂ ceramics were prepared by the conventional solid state reaction method, and their dielectric properties and crystalline structure were investigated. It was found that they were quite similar with the CaCu₃Ti₄O₁₂ ceramics, showing giant dielectric-permittivity properties with ε' larger than 7×10³. Within the measuring frequency range of 40 Hz-100 MHz, a single dielectric relaxation with the characteristic frequency around 1 MHz was detected at room temperature or below whereas an additional one in low frequency region is also observed at high temperatures. Furthermore, the existence of CuO secondary phase was confirmed by X-ray diffraction. In general, the results can be explained by the similar mechanism of internal barrier layer capacitance effect which was formerly proposed for CaCu₃Ti₄O₁₂ ceramics. Here, it is worthy pointing out that the tanδ of NaCu₃Ti₃SbO₁₂ ceramics is lower than 0.05 in a large frequency range from 40 Hz to 7 kHz, and the tanδ at 1 kHz is lower than 0.05 in a large temperature range of -50℃ to 80℃ at 1 kHz, which is a desirable characteristic for practical applications.

With self-assembled monolayer (SAM) as template, cubic cuprous-oxide (Cu₂O) crystals with preferred orientation are obtained via simple and effective electrochemical redox process. Micro-region X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to characterize the as-grown Cu₂O crystals. Besides uniform morphology and crystal size, the micro-crystals take preferred orientation that is strongly influences by the pre-modified SAM on substrate. The experiments indicate that the SAM not only acts as the growing template for the crystals, but also strongly affects the electrochemical redox process. To explore its sensing properties, the Cu₂O crystals were grown onto a micro-cantilever to detect DMMP (dimethyl methylphosphonate) vapor. The sensing mechanism is complexation of phosphonyl group with Cu(I) that generates surface-stress at the cantilever surface. Tens of ppb DMMP vapor is reproducibly detected.

Electromagnetic wave absorbers (EMWAs) (i.e. microwave wave absorbers) are important materials for military equipment. Ideal EMWA should exhibit thin matching thickness, low density, broad bandwidth, and strong EM absorption. The recent advances of EMWA were reviewed in this study, and the shortcomings in current studies and approaches for further researches were suggested. Recent researches on EMWAs are mainly focused on the preparation of nanocomposites, doping or surface modification, and changing the micro-morphology and structures of EMWA. However, these studies concentrated on traditional EMWAs and applied researches, which lack of theoretical guidance and breakthrough innovations. Further investigations should pay more attention on the nanocomposites and nanocomposites with structure designing under the guideline of electromagnetic wave theory. Moreover, smart materials and structures and metamaterials are promising EMWAs with excellent properties.

Diluted magnetic semiconductors (DMSs) are new functional materials formed by doping a few percentages of magnetic ions in nonmagnetic semiconductors. Recently, the ferromagnetism origin and magnetism theory are the research hotspot in the field of DMSs. It is still unclear how the ferromagnetism is induced between the doped magnetic ions and the carriers. In this paper, the recent progress in magnetism theory was reviewed. The typical theories including RKKY, mean field theory, double exchange and bound magnetic polaron were elucidated in detail. The hotspot of experimental, theoretical research and existing problems were evaluated.

TiO₂ nanomaterials are the research hotspots among recent nanotechnologies, and those are demonstrated having the crucial application prospects in the solar light photocatalytic splitting water into hydrogen, the photocatalytic reduction of CO₂, as well as dye-sensitized solar cells. This article mainly reviewed recent research trends of TiO₂-based nanomaterials, the existing problems, and the advances in the clean energy utilization. Especially, the hot research issues such as non-metallic element doping, high energy facets exposed titania, and compact film for dye-sensitized solar cells, were commented and prospected.

Nanosized titania particles consisting of anatase, rutile and brookite phases were synthesized under solvothermal conditions with different alcohols as solvents, hexamethylene tetramine (HMT) as precipitant as well as precursor of titanium trichloride. XRD, TEM, UV-Vis and XPS spectra were employed to characterize these samples. The effect of treatment solvent and HMT amount on the phase composition and photocatalytic activity of titania were investigated. It is found that anatase is easier to form at acidic condition, but rutile and brookite at basic condition, using methanol as solvent. The TiO_2-xN_x with nitrogen doping in TiO₂ is obtained under solvothermal conditions. The results of photocatalytic degradation to methyl orange show that the mixed crystallite of anatase and brookite has the best photocatalytic activity.

By using the hydrothermal method, the ZnO nanorod arrays with different morphologies were synthesized on ZnO nanoparticle-coated transparent conductivity glasses (TCO) at low temperatures by controlling the pH value of precursory solutions. The ZnO nanorod arrays were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), high-resolution transmission electron microscope (HRTEM) and ultraviolet-visible spectrophotometer (UV-Vis). Furthermore, the mechanism was primary discussed. The results show that the ZnO nanorod is a single crystal and it grows along c axis. When the pH value is about 10.5, the array is well-aligned and the diameter of the nanorod is uniform. Optical characterization shows that the optical transmittance of the film is higher than 80% in the visible wavelength and its band gap is about 3.25eV.