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Sc-based nanomaterials have attracted considerable attention due to their unique optical properties different from those of Ln/Y-based nanomaterials. However, studies on Sc-based nanomaterials are far from comprehensive. Particularly, nanoscale alkaline (Ca, Sr and Ba) scandium fluorides were almost ignored for their stringent synthetic conditions. Herein, we synthesize high-quality tetragonal phase Ba3Sc2F12 nanocrystals with uniform morphology and good dispersibility by carefully tailoring the reaction conditions, such as the molar ratio of reactants, temperature and reaction time. Then, the upconversion (UC) luminescence property of Ba3Sc2F12:Yb/Er (Ho) samples is investigated in detail. The doping concentrations of sensitizer (Yb3+) and activator (Er3+ and Ho3+) are optimized for the strongest UC luminescence, of which the corresponding energy transfer processes are also discussed. Moreover, tetragonal Ba3Sc2F12 nanocrystals can gradually transform into hexagonal Ba4Yb3F17 nanocrystals with the increase in Yb3+ doping content. This work provides a novel type of Sc-based nanomaterials with strong red UC emissions which are promising in high-resolution 3-dimensional color displays, laser, bioimaging and biolabels.

Y-based fluorides have been recognized as most efficient host materials for upconversion photoluminescence (UC-PL). Herein, we have produced a series of Yb/Er doped Y-based fluorides with specific crystal structures, shapes and sizes. The selective growth process is governed by our pre-designed surfactant 4, 4′-((2,5-bi’s (2-(diethylamino) ethoxy) −1,4-phenylene) bis (ethyne-2,1-diyl)) dibenzoic acid (DBA) and selective solvents. It is shown that highly pure hexagonal microprisms and cubic microspheres of NaYF4: Yb/Er could be selectively grown in water at low and high content of DBA, respectively, while only orthorhombic nanowires and microflowers of YF3: Yb/Er could be obtained in ethanol. Finally, all these materials obtained exhibit strong UC-PL signal while the UC emission intensity of the NaYF4: Yb/Er hexagonal microprisms is much higher than those of the cubic microspheres and orthorhombic YF3 nanowires and microflowers. This work provides a novel method for selective crystal growth of Y-based fluorides with specific shape, size, crystal phase and highly UC-PL efficiency by breaking the intrinsic limitation of crystal growth habit, which could be possibly extended to the controlled synthesis of other related materials.

The morphology evolution and hygroscopicity reduction of Y2Mo3O12 crystal are investigated by introducing (LiMg)3+. With increasing the content of (LiMg)3+, the hygroscopicity of Y2Mo3O12 is reduced obviously depending on the XRD, Raman and DSC/TG results, and the morphology of Y2Mo3O12 transforms remarkably from amorphous crystal to octahedra and then rod. The results suggest the effects of (LiMg)3+ on repelling water molecules and improving the growth of Y2Mo3O12 crystal, which could be a reflection of the decrease of micro-channels in the structure. Some (LiMg)3+ substitute Y3+ in Y2Mo3O12 to form solid solutions of (LiMg)2−xYxMo3O12 with octahedra and then rod, and excess (LiMg)3+ leads to the formation of (LiMg)2Mo3O12 due to the difficulty in substituting Y3+ with (LiMg)3+. The substitution of Y3+ for (LiMg)3+ reduces the thermal expansion coefficient of Li-ion battery material of (LiMg)2Mo3O12.

In negative thermal expansion (NTE) materials, rhombohedral TiF3 as a new member is predicted from first-principles calculation. The NTE behavior of rhombohedral TiF3 occurs at low temperatures. In our work, the NTE mechanism is elaborated in accordance with vibrational modes. It is confirmed that the rigid unit mode (RUM) of internal TiF6 octahedra in low-frequency optical range is most responsible for the NTE properties.

The reaction pathways for the synthesis of Ca 1− x Sr x Zr 4 P 6 O 24 (0 x 3 , ZrO 2 and P 2 O 5 by solid state method are studied. It is found that there are two reaction pathways: one is through an intermediate phase to final products while another is direct reaction from starting materials to destination ones, depending on experimental procedures and drying and sintering temperatures. By well controlling the reaction along the latter pathway, the sintering time of Ca 1− x Sr x Zr 4 P 6 O 24 (0 x 1− x Sr x Zr 4 P 6 O 24 and related refractory compounds.

The internal polyhedral distortions have been reported experimentally in orthorhombic Y2Mo3O12 as a negative thermal expansion (NTE) material. To reveal the relationship between NTE and polyhedral movements, distortions, the vibrational properties of Y2Mo3O12 have been studied using first-principles calculations. The lowest optical branch corresponding to translational mode of the O bridge atom in Y O Mo linkage has the largest negative Gruneisen parameter and therefore contributes most to the NTE behavior. The different vibrational eigenvectors of oxygen atoms relative to Y or Mo atoms can cause internal polyhedral to distort unevenly. Herein, an extended 3D model of the connected unit YO6 MoO4 based on the Y O Mo linkage presents a simultaneous dynamic process, i.e. the YO6 octahedra and MoO4 tetrahedra distort unevenly, along with both polyhedra being closer which makes the volumetric contraction. This model is helpful to improve the mechanisms of NTE and may be applied in the whole A2M3O12 family.

The effective dielectric constant of the graded composites was calculated with three different methods, namely, the nonlinear differential effective dipole approximation method (NDEDA), the Maxwell-Garnette method (MGT) and the sum rule method (Sum). In each layer of the graded composites, the distribution of the dielectric constant follows a Drude form. Our numerical results show that when the number of layers N inside the graded composites increases, a gradual transition from sharp peaks to an emerging broad continuous band is clearly obtained. Moreover, the results obtained by the MGT and sum rule methods achieve a good agreement with that by the NDEDA method when N is approaching infinity.

We review the recent theoretical study on the optical properties of one-dimensional soft photonic crystals (1D SPCs) with ferrofluids. The proposed structure is composed of alternating ferrofluid layers and dielectric layers. For the ferrofluid, single domain ferromagnetic nanoparticles can align to a chain under the stimuli of an external magnetic field, thus changing the microstructure of the system. Meanwhile, nonlinear optical responses in ferrofluids are also briefly reviewed.

A rapid synthesis method is introduced for the synthesis of low thermal expansion materials of Ca 1− x Sr x Zr 4 P 6 O 24 ( x = 0, 0.5 and 1) and optimum synthesizing conditions are obtained. It is shown that these materials can be synthesized by one-step sintering by putting the preheated mixture of CaCO 3 , SrCO 3 and NH 4 H 2 PO 4 directly into a pipe furnace at the sintering temperature (1673–1873 K). With this method, the sintering procedure is much simplified and sintering time and energy exhausts are considerably reduced with respect to the conventional solid state reactions which usually require multiple-step and longer time sintering at different temperatures with intermediate grindings for the synthesis of these materials. By putting the samples directly at the sintering temperature, the formation of the secondary phase ZrP 2 O 7 can be largely avoided. This insures the rapid synthesis of Ca 1− x Sr x Zr 4 P 6 O 24 . MgO is introduced to increase the density of Ca 0.5 Sr 0.5 Zr 4 P 6 O 24 ceramics. A sintered density of 3.10 g cm −3 , relative density of 96.2% for Ca 0.5 Sr 0.5 Zr 4 P 6 O 24 is obtained with 1.0 wt.% MgO. The coefficients of thermal expansion are about 0.27 × 10 −6 K −1 . Raman spectroscopic and differential scanning calorimetry (DSC) analyses reveal that there are no phase transitions of all the samples from 113 K to 1423 K.

The electronic band structures, partial and total spin density of states of Cr, Fe, Mn and Ni doped β-Ga2O3 are studied. It is shown that there exists only one spin polarized state around the Fermi level for all doped β-Ga2O3. Ferromagnetism is predicted for Mn and Ni doped while spin-glass ground states are predicted for Cr and Fe doped β-Ga2O3. All doped β-Ga2O3 exhibits intermediate bands which are filled with only one spin state electrons and isolated from valence and conduction bands due to the splitting of the 3d orbitals by the potential of crystal and spin interaction

ZrO2-ZrW2O8 diphasic composites with controllable coefficients of thermal expansion (CTEs) are synthesized by rapid in-situ reactive sintering with ZrO2 and WO3 as reactants. High density of ZrO2-ZrW2O8 composites without decomposition of ZrW2O8 is obtained with Y2O3 sintering additive. The CTEs of specimen with ZrO2 to ZrW2O8 mass ratio 1:1.0, 1:1.3, 1:1.5 and 1:2.0 are measured to be about 1.20×10−6, 0.31×10−6, -0.78×10−6 and -1.13×10−6 K−1, respectively. Raman mappings demonstrate homogenous dispersions of ZrO2 and ZrW2O8 in the ZrO2-ZrW2O8 composites. In addition to the role as sintering additive, some Y3+ cations enter the lattice to substitute Zr4+ in ZrW2O8, leading to an increase in disorder and a decrease in phase transition temperature of ZrW2O8 in the composites.

Field emission property of Ga-doped carbon nanotube (CNT) film has been studied and compared with those of un-doped, N-doped as well as B and N co-doped CNT films. It is found that the Ga-doped CNT film exhibits superior field emission property to the other films. The turn-on field for Ga-doped CNT film is well below 1.0 V/μm, lower than those for un-doped (2.22 V/μm), N-doped (1.1 V/μm), B and N co-doped (4.4 V/μm) CNT films. Its current density reaches 5000 μA/cm2at 2.6 V/μm which is well above those for un-doped (1400 μA/cm2), N-doped (3000 μA/cm2) as well as B and N co-doped (2) CNT films at applied electric field of 5.7 V/μm. First principles calculations were carried out to obtain the binding energy and electronic nature altering of a CNT by Ga doping. It is shown that Ga-doped CNT (8,0) alters from semiconductor to intrinsic metal and a binding energy of 2.7527 eV is obtained. The field emission property can not simply be explained by the defect concentration, but can be understood by significant altering in the local density of states near the Fermi level introduced by dopants.

Cracking is a serious problem in laser-clad hardfacing layers due to inhomogeneous distribution of coarse brittle phases and stress induced during rapid solidification. Tantalum carbides and borides which can form and precipitate at much higher temperatures are tentatively designed to inhibit the formation of the coarse brittle phases of chromium carbides and borides. It is found by XRD analysis that TaC, Ta4C3, TaB and Ta5B6 were formed in-situ and the coarse brittle phases were largely avoided in laser-clad Ni-based layers. It is also found that the formation sequence of these species is governed by their precipitation temperature instead of the rule determined by the standard free energy of formation. The formation of the chromium carbides and borides is inhibited due to the priority of formation of tantalum carbides and borides during rapid solidification. SEM and penetration visualization examinations show that the microstructure is markedly refined and the cracking susceptibility is significantly reduced by this method. The microhardness of the layers maintains at about 800 Hv.

A simplified method with much lower time and energy costs is presented for the rapid synthesis of low thermal expansion materials of CaZr4P6O24, SrZr4P6O24 and their solid solution Ca0.5Sr0.5Zr4P6O24. The coefficients of thermal expansion of CaZr4P6O24, SrZr4P6O24 and Ca0.5Sr0.5Zr4P6O24 are measured to be -1.45×10-6, 2.1×10-6 and 0.26×10-6, respectively. Raman spectroscopic study confirms the formation of the solid solution of Ca0.5Sr0.5Zr4P6O24 though its symmetric and asymmetric stretching modes are obviously broadened with respect to those of CaZr4P6O24 and SrZr4P6O24 due to the lattice deformation by incorporation of Ca2+ and Sr2+ with different cation size. The shifts of the asymmetric stretching Raman modes and the librational/translational modes with temperature in Ca0.5Sr0.5Zr4P6O24 are between those in CaZr4P6O24 and SrZr4P6O24, suggesting a cancelling effect of Ca2+ and Sr2+ cations in the thermal expansion of Ca0.5Sr0.5Zr4P6O24.

Ceramic systems of template explains and demonstrates how to prepare your camera-ready Ceramic systems of Bi2O3 and La-doped SrTiO3 (LST) solid mixtures La0.2Sr0.8TiO3–x%Bi2O3 (x = 0, 20, 25, 30, 35) are prepared and explored as possible anode materials for solid oxide fuel cells. It is shown that the conductivity of La0.2Sr0.8TiO3–x%Bi2O3 composites increases from 0.15 to 1.4 S cm−1 in 97%H2 +3%H2O at 800°C with increasing the content of Bi2O3. Electrochemical impedance spectra indicated that the addition of Bi2O3 into LST can significantly reduce the fuel cell’s polarization and refine the grains and increase the triple phase boundary, leading to a better performance of the fuel cells. The results suggest potential applications of LST–x%Bi2O3 composite as SOFC anode materials.

The crystal structure of hafnium tungstate displays unusual property of isotropic negative thermal expansion in a wide temperature range which brings about a number of important potential applications. In this work, densely packed hafnium tungstate blocks are rapid synthesized by CO2 laser. The result of XRD and Raman spectra show that the samples contain single cubic phase of α-HfW2O8 with space group P213. The SEM observations show that the sample is composed of nano-rods which grow horizontally on the surface and in the interior. The nano-threads in the interior are composed of densely packed nano-crystallites.

A laser rapid solidification (LRS) method has been developed for the synthesis of La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 3− δ (LSGM), an excellent electrolyte for solid oxide fuel cells. It is shown that pure perovskite LSGM phase can be produced within a few seconds with this method under optimized synthetic conditions and it solidified in densely packed and relatively ordered ridge-like blocks with a relative density of 98.5%. The unique microstructures are attributed to the oriented crystalline growth in the molten pool dictated by heat transfer directions. It is found that the samples synthesized by LRS exhibit superior electrical properties for fuel cell applications to those by solid state reactions. The conductivities of 0.027, 0.079 and 0.134 S cm −1 measured at 600, 700 and 800 °C, respectively are much higher than those of the samples synthesized by solid state reactions with similar purity and density.

The effect of V2O5 on the refinement of microstructures and the reduction of cracking susceptibility of laser-clad NiCrBSiC hardfacing coatings are investigated. It is shown that high volume fraction and inhomogeneous distribution of the coarse brittle phases of chromium borides and carbides in NiCrBSiC layer are the dominating origins for hot cracks. The addition of V2O5 has an apparent effect on enhancing the toughness, refining the microstructure and reducing the cracking sensitivity of the coating. This is attributed to the generation of vanadium borides and carbides. The vanadium borides generate prior to and consequently inhibit the formation of chromium borides during rapid solidification because of lower standard free energy of formation of the former. They also restrain the growth of chromium carbides and make them distribute homogeneously. The reasons for crack initiation and distribution are discussed based on the microstructures of the cladding layers. It is demonstrated that the generation of cracks is determined by the microstructure of the cladding layers and the occurrence of cracking is governed by heat stress.

Zirconium tungstate was successfully synthesized by rapid solidification with a CO2 laser. Scanning electron microscope observation shows that nano-threads/rods grew horizontally on the surface region and vertically in the interior. The nano-threads in the interior are composed of densely packed nano-crystallites. Raman spectroscopic study shows that the samples solidified in an orthorhombic structure when the laser scan speed was ?2?mm?s?1. This is explained by a compressive stress induced during the rapid solidification process due to a sudden drop of temperature from the molten pool to the ambient. The possibilities for tuning the strength of the compressive stress and controlling the production of different phases of ZrW2O8 are proposed. It is analysed and confirmed that the compressive stress can be effectively reduced by lowering laser scan speed. ZrW2O8 samples with cubic structure are produced with laser scan speed

Densely packed zirconium tungstate blocks were synthesized by rapid solidification with a CO2 laser. The structure and phase transition properties of the samples were studied by Raman spectroscopy and X-ray diffraction. Raman spectroscopic study reveals that zirconium tungstate solidifies with an orthorhombic structure. This is attributed to the pressure encountered by the samples during rapid solidification. Several Raman bands change discontinuously at about 390 K, indicating a phase transition from the γ- to the α-phase occurring at this temperature. In the β-phase, most of the Raman modes give rise to negative Gruneisen parameters, suggesting contribution of the corresponding optical phonons to the negative thermal expansion coefficient of the material, at least for the β-phase. A recovery of the γ-phase was observed when the samples were cooled to room temperature. This suggests that the cubic structure is metastable only at temperatures above 390 K, and at room temperature the γ-phase is preferred. Copyright © 2007 John Wiley & Sons, Ltd.

The preparation and characteristic of in situ synthesized B4C particulate reinforced nickel composite coatings on A3 steel substrate by laser cladding, especially the microstructure and wear-resistance of this coating have been investigated. Good finish and in situ synthesized B4C particulate reinforced composite coatings can be achieved employing a proper amount of (B2O3 + C)-doping under a suitable laser power and scanning velocity. It is found that a new white particulate phase appears in the coatings. The microstructural and metallographic analyses made by a scanning electron microscopy, energy-dispersive spectrometer and X-ray diffractometer suggest that the new white particulate phase includes the in situ synthesized B4C in laser cladding process. The white particulate, together with the acicular dendrite, presents as the primary reinforcements of the coatings. Because of the generation of these particulates and their homogeneous distribution in the matrix, the composite coating gives very high hardness of Hv0.31400 and excellent wear resistance, which is two times higher than that of pure Ni60 coatings. In addition, the bottom, center and upper region in the composite coatings exhibit the different microstructure. The microstructure in the bottom region consists mainly of acicular dendrites dispersed in the γ(NiFe) matrix. And that the microstructure located at the center and upper regions contains both acicular dendrites and white particulates dispersed in the matrix of the interdendritic lamellar eutectic. Moreover, the number of white particulates in the upper region is more than that in the center region.

The geometric and electronic structures of the PbS, PbSe and PbTe(0 0 1) surfaces were investigated by using the density functional theory. The calculations show that the (0 0 1) surfaces of these semiconductors do not reconstruct but exhibit oscillatory geometric relaxation to some extent. The interlayer distance shift and the intralayer rumpling have some obvious regularity. The calculations also show that the electronic structures of these semiconductors are very similar. The direct surface band gap locates at the X point and there are no new surface states appearing in the fundamental band gap. Some p characters surface resonance states appear mainly in the valence and the conduction band, and the other surface state with the anions s character also appears in the deep band gap below )10.0 eV. � 2003 Elsevier B.V. All rights reserved.

The effects of TiO2-doping on the properties of laser clad nickel-based composite coatings on carbon steel substrates have been studied. It is shown that good finish and crack- and porosity-free coatings can be achieved under a proper amount of TiO2-doping and a suitable laser-scanning speed. Both the cracking sensitivity and the wear resistance are considerably improved at the little expense of a decrease in hardness. This can be attributed to the improvement of the coatings to the refinement of the microstructure both in grain sizes and their homogeneous distribution in the coatings. The microstructural and metallographic analyses by a scanning electron microscopy, energy-dispersive spectrometer and X-ray diffractometer suggest the generation of new phases such as TiB2 and TiC upon the TiO2-doping. Thus, it can be concluded that the refinement in microstructure is due to both an increase in number of nucleation sites by the formation of TiB2 and TiC in the melt pool and an impediment to the growth of larger crystallites by the deposition and insertion of Ti atoms on the grain boundaries.

CNx nanotubes have been synthesized by thermal decomposition of ferrocene/ethylenediamine (Fe(C5H5)2/C2H8N2) mixture at 1053–1353 K. The effect of temperature on the growth and structure has been studied by transmission electron microscopy (TEM) and Raman spectroscopy. With increasing growth temperature, the average diameter of the nanotubes increases and a morphology transition from thinner polymerized ‘pearl-like’ nanobells to thicker ‘bamboo-like’ compartments occurs. The FWHMs of the D, G and D* bands reduce while the normalized intensities of the D and D* bands with respect to G band change conversely with increasing growth temperature. The opposite trends in intensities between the D and D* bands are interpreted by their correlation with K-point phonons in disordered sample. Raman spectroscopic studies showed that the degree of disorder and consequently the nitrogen incorporation decrease with increasing growth temperature. Based on these results, we presented two new parameters to describe the degree of disorder in CNx nanotubes.

The Raman spectrums of hemoglobin from 20 normal persons and 21 esophageal cancer patients were measured and analyzed in the present paper, the results show obvious differences between the Raman spectrums of esophageal cancer patients and normal persons. Compared with normal persons, there are more iron ions in low spin state and less in high spin state in the hemoglobin of esophageal cancer patients. It indicates that some iron ions in high spin state turned to low spin state because of cancerization, and this experimental result coincides with the fact that hemolysis is more likely to occur in cancer patients. Principal component analysis (PCA) was employed to get a three-dimensional scatter plot of PC scores for the health and cancer groups, and it can be learned that they are distributed in separate areas. By using the method of discriminate analysis, it was found that the diagnostic algorithm separates the two groups with sensitivity of 90.5% and diagnostic specificity of 95%, and the overall diagnostic accuracy was 92.7%. The results from this exploratory study demonstrate that Raman spectroscopy combined with multivariate analysis would be an effective method for early diagnosis of esophageal cancer.

The surface-enhanced Raman scattering of fulvic or humic acid adsorbed on copper electrodes demonstrates a unique resolution-enhanced effect. The effect is due to chemical binding of humic substances on copper surfaces. It is deduced that only a few kinds of chemically and geometrically favorable groups or portions such as carboxylic ions and pyridine-substituted rings in the humic aggregates specifically bind onto the copper surfaces while the rest dangles in the solutions. Since the rest are far from the surface and their SERS signals are too weak to be observed, the SERS spectra only characterize the binding groups specifically and therefore they are highly resolved and simple. Such a unique resolution-enhanced effect may be valuable to reveal specific clues regarding the binding groups of humic substances, particularly at low concentrations typically found in aquatic environments.

In the present study, the UV-Vis absorption spectra and resonance Raman spectra of free bilirubin and bilirubin complexes with copper(II), silver(I) and gold(III) excited with different wavelengths were measured. From these results and from the band assignments, it is found that complexes of bilirubin-metal have different structures. This is probably due to the difference of ionic charge and ionic radius between the metal ions.

In order to develop silicon-based modulation or emission materials, silicones covered by porous silicon (ps) thin film were characterized about terahertz transmission and emission properties from 0.5T to 10T frequency by THz Time Domain spectrograph. Ps films were etched different morphologies through hydrothermal method. According to SEM, micro-surface-structures of these ps films were divided into three types: crater, quasi nano-pillar-array and porous. Terahertz wave transmission amplitude of cater samples was decreased largest and its transmission time delay was the least among the three samples. Compare to cater sample, THz transmission intensity of quasi-nano-pillar sample increased 27%, porous one increased 53%. For time delay, quasi-nano-pillar sample was 0.04ps, porous one was 0.3ps. The first two type's samples had low-pass characteristics and porous samples had cascade band-pass characteristic. There were much absorption peaks in the spectrum of quasi nano-pillar-array sample and porous one. Positions of these peaks had very closed relationship to the micro-surface-structures of ps thin films. In addition, samples could generate μW THz emission at 10THz area after excitation by femtosecond laser. Experiments showed that, both shape and size of these ps films appeared to change and control transmission and emission properties of silicon in 0.5T to 10T, such as transmitted intensity, absorption frequency and emission properties, so nano-micro system porous silicon could be considered as a new material for THz modulation, emission and it could be applied to make integration wide-spectral device.

This paper describes a new concept related to the MEMS(Micro Electro Mechanical system) imaging-array sensors with the structure of micro-cantilever-arrays for detecting far IR and THz radiation. The measure principle is based on an improved optical lever and the core component is a set of micro-displacement measuring device with nano-degree displacement measurement. The amplification coefficient of this improved optical cantilever can reach 10 2 ~10 3 times, combined with a high resolving power to 10 -10 m. Compared with focal plane arrays sensors, these tape sensors have the ability to measure deformations of micro-cantilever-arrays caused by far IR or THz radiation directly, which can increase the radiation detector sensitivity. The validity of this method is proved by practical experime nts. Imaging-array sensors, based on this measure principle, can be made into a new-type MEMS Far IR or THz sensors. Keywords: far IR, Terahertz sensor; MOEMS, imaging-arrays sensor, nano- degree displacement

The confocal Raman micro-spectra of breast tumor limbic fat tissues of forty cases after surgery were collected. Substantial differences were found among breast infiltrative ductal carcinoma, hyperplasia and fibroadenoma, which is possibly to be used as a character of breast cancer and other breast tumor and offers the evidence for the breast tumor diagnosis. So, the Raman spectroscopy of the breast limbic fat tissue is of great value.

Raman spectra of boron carbonitride (BCN) nanotubes made by thermal decomposition under different temperatures and with different catalysts were analyzed. The intensity ratio of D to G band, I(D)/I(G), increases and then decreases with the increase of the temperature. It was indicated that there exists an optimal temperature under which B and N incorporation is maximum. The catalysts influence also the Raman spectra of the BCN nanotubes. I(D)/I(G) is higher with cobalt/ferrocene and nickel/ferrocene than with cobalt, nickel and cobalt/nickel as catalysts. This means that better BCN nanotubes with B and N contents can be produced with the former. The results were confirmed by TEM observation.

The authors collected the absorption spectrum of RPMI 1640 and DMEM substrates that cultivated Hela and CNE by UV-3101 spectrophotometer and analysed the absorbability of proteins in the substrate. The absorption peaks of the RPMI 1 640 culture medium that cultivated cells for different times shifted from 227 to 222 or 218 nm and from 278 to 280 nm respectively; while during growing course of cultivated cells, one of the absorption peaks of DMEM culture medium shifted from 224 nm to one near 221 nm, and the absorption peak 278 nm almost had no shift. All of these shifts show that the content of each amino acid such as tryptophan and casein has already changed. That is, during the growing course of cultivating cancer cells, the tryptophan and casein were not depleted equivalently. In the growth period of Hela and CNE, they consumed different amino acid. So they need different component proportion for amino acid.

Porous silicon (PS) with good luminescent stability and homogeneity was fabricated by using a novel titanium-doped stain etching approach. The blue shift and degrading of the photoluminescence (PL) were not observed when stored and annealed in ambient air. The good luminescent stability is attributed to the surface passivation of the PS by both oxygen and titanium during fabrication. The PL position is independent of the etching time. The results indicate that the photon excitation process meets the quantum confinement mechanism since the PL intensity reaches its maximum when the particle size-dependent band gap is in resonance with the exciting photon energy. The photon emission process is, however, not a direct band-band transition, rather through a surface state within the band gap, instead.

This paper designed a perfect optical absorber based on three-tier gate nanostructure, which shows a wide-band perfect absorption in the wavelength range of 200–560 nm as a transverse wave incidents to the nanostructure with the incident angle 35°< θ< 65°. When θ = 45°, a wide absorption band with the absorption rate more than 94% is observed, with the maximum of absorption rate reaching 99.3% at the wavelength of 430 nm. We also analyze the thermal characteristics of the perfect absorber. The band ranging from 560 nm to 1200 nm presents an increasing absorption rate with the increase of temperature. The calculation results of multi-physics analysis indicate that different cooling method causes different temperature distribution for the perfect absorber. This three-tier gate perfect absorber may find applications on broadband visible detectors, microbolometer and thermal imaging.