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Low-cost porous ceramics with controllable pore size were prepared by using natural clay and silica as starting materials and organic polymer sponge as template. The properties of the resulting ceramic material, such as pore size, porosity and mechanical strength, were characterized using different techniques. The results show that this novel preparation procedure provides an easy pathway to produce porous ceramics according to specification for a range of applications.

Recently Lacey extended Chanillo's boundedness result of commutators with fractional integrals to a higher parameter setting. In this paper, we extend Lacey's result to higher dimensional spaces by a different method. Our method is in terms of the dual relationship between product BMO and product Hardy space and the maximal function characterization of product Hardy spaces obtained by S.-Y.Chang and R. Fefferman. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

A new targeted delivery system was developed in this paper by depositing magnetic NPs on protein containers which were prepared by sonicating oil in a protein solution. The deposition was conducted by layer-by-layer technique and monitored by zeta potential measurement. Such prepared samples can be targeted delivery in an external magnetic field. The hydrophobic dye TPP, as a model of drug, was loaded in the containers by dissolution in the oil phase before sonication. The containers loaded with dye are stable and can sustain the deposition treatment without loss of dye due to the protection of protein nanoshells.

This paper presents an automatic approach for the evaluation of isochromatics and isoclinics in photoelasticity using complementary phase shifting. First, the phase values of the isoclinics are obtained from four images in the plane polarizer arrangement by rotating the polarizer and analyzer simultaneously. Then, through use of the isoclinics, a full-field description of the first principal stress orientation with respect to the horizontal axis is determined. Phase maps for the isochromatics are then achieved at eight discrete orientations through sequential analyzer rotations. With the first principal stress orientation known from the isoclinic phase map, a whole-field description of the phase values of the isochromatics is then constructed. The proposed method was validated for the problem of a ring under diametrical load.

NiAl2O4-metal composite material is an effective candidate for anodes used in industrial production of aluminium as a substitute for graphite anodes. NiAl2O4-Cu-Ni anode was prepared by spark plasma sintering in present paper. According to the density and electrical conductivity of the anodes, the optimal process parameters were given and the result showed that sintering temperature had the most significant influence on the properties of the inert anodes. Moreover, NiO was added to the inert anodes. The results showed that adding NiO will highly increase electrical conductivity of the inert anodes. SEM and optical microscope were applied to study the mechanism of the effect of NiO on the inert anodes.

Here we report a study on controllable synthesis of hierarchical silver structures via regulating reaction kinetics. Silver particles with various morphologies are synthesized by a solution-based reduction approach at the addition of amino acids. The amino acid is used to coordinate with silver ions to slow down the reduction of silver ions. With the increase of glycine concentration, the morphologies of silver particles switch from dendrites, to flowers and to compacted spheres, which is attributed to the decrease of reaction rate as a result of the coordination. Three more amino acids are examined and confirms the role of reaction kinetic in shaping silver particles. Furthermore, by increasing the concentration of the reductant, the silver morphologies change from compact spheres to loose flowers as a result of the increase of reaction rate. Therefore the silver hierarchical structure can be reversibly switched by reaction kinetics. The silver particles synthesized are tested for surface enhanced Raman scattering (SERS) property and the dendritic particles present a remarkable SERS activity. This study shows that reaction kinetics is a powerful tool to tune hierarchical structures of silver particles, which is expected to be transferable to other material systems.

Let (, d,μ) be a space of homogeneous type in the sense of Coifman and Weiss. Assuming that μ satisfies certain estimates from below and there exists a suitable Calderon reproducing formula in L2(), the authors establish a Lusin-area characterization for the atomic Hardy spaces Hpat() of Coifman and Weiss for p ∈ (p0, 1], where p0 = n /(n + e1) depends on the “dimension” n of and the “regularity” e1 of the Calderon reproducing formula. Using this characterization, the authors further obtain a Littlewood–Paley g*λ-function characterization for Hp () when λ > n + 2n /p and the boundedness of Calderon–Zygmund operators on Hp (). The results apply, for instance, to Ahlfors n -regular metric measure spaces, Lie groups of polynomial volume growth and boundaries of some unbounded model domains of polynomial type in ℂN. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

By use of special wavelet bases associated to accretive or pseudo-accretive functions, it was proved that all Calderon-Zygmund operators satisfying certain conditions form an algebra. In this article, a similar result is proved for more general para-accretive functions. Since wavelet bases are not available for this general setting, the new idea used here is to apply the discrete Calderon-type reproducing formula associated to para-accretive functions developed in [14]. This new method can be applied to many other problems, where wavelet bases are not available.

Hollow calcium carbonate (CaCO3) particles were synthesized by bubbling CO2 in the solution of calcium chloride (CaCl2) with the presence of ammonia at room temperature. In this method, CO2 bubble, besides as reactant, has an important role as a template for forming hollow particles. The precipitation was carried out by controlling the precipitation condition, such as pH, flow rate and additives. Hollow calcium carbonate particles were precipitated with the major crystal phase of vaterite. An interesting finding is that magnesium ion (Mg2+) can suppress the transformation of vaterite to calcite by inhibiting the growth of the calcite.

Calcium carbonate particles were prepared by bubbling the mixed gas CO2/N2 into CaCl2 solution. The effect of initial CaCl2 concentration on the morphology and phase of CaCO3 was discussed with the help of XRD and SEM measurements. The samples prepared at low CaCl2 concentration composed mainly of spherical vaterite. With the increase of CaCl2 concentration, more and more rhombic particles were formed and mixed with spherical particles. When the initial CaCl2 concentration increased to 0.3 mol/L, only rhombic calcite was formed in the final product. The change of CaCO3 morphology with the increase of CaCl2 concentration was attributed to the excess of Ca2+, which speeded the transformation of vaterite to calcite, thus more rhombic calcite was formed at higher CaCl2 concentration.

Precipitated calcium carbonate particles were prepared by passing CO 2 /N 2 mixed gases into CaCl 2 solution. The nucleation, crystallization and transformation of vaterite at controlled pH were investigated in this paper. The control of pH was conducted by the addition of ammonia. The results showed that addition of ammonia induced a local high supersaturation and continuous nuclei formation, which is in favor of the growth and agglomeration of vaterite nuclei while inhibiting the transformation of vaterite to calcite. The nearly pure vaterite is ready to form at the control of pH.

Hollow calcium carbonate (CaCO3) particles were synthesized by bubbling CO2 in the solution of calcium chloride (CaCl2) with the presence of ammonia at room temperature. Hollow calcium carbonate is a potential component to be used as pharmaceuticals, agrochemicals, and catalysis. This paper investigated the effect of additive on the hollow structure. In this study was used vanadate ion as additive agent. Physical characteristics of precipitate were evaluated using scanning electron microscopy (SEM) and X-ray diffraction (XRD).

The feasibility of bubble templating method to prepare hollow particles was tested in this paper by passing a bubble into a silica sol. The silica sol was prepared by mixing TEOS, water, alcohol and hydrochloric acid. To control the gel point, the reactants and their concentrations were varied in each experiment. After the sol was prepared, an ammonia bubble was introduced into the prepared sol through a capillary tube. With the catalysis of ammonia, the silica sol gelled on the surface of bubble and formed a hollow gel particle. The nucleation of silica gel on the surface of bubble was discussed in this paper.

Precipitated calcium carbonate (PCC) was prepared by bubbling a CO 2 /N 2 mixed gas into a CaCl 2 solution. The influence of preparation conditions on the phase and morphology of PCC was discussed with the help of XRD and SEM measurements. The results showed that the initial CaCl 2 concentration, flow rate and temperature play an important role on the morphology of PCC. At low initial CaCl 2 concentration or high flow rate, spherical vaterite was preferably formed. Otherwise, the rhombic calcite was ready to form. Temperature is a determining factor on the formation of aragonite. Needle-like aragonite was precipitated at 60 °C. The results also indicated that both the bubbling time and stirring rate have a minor effect on the phase and morphology of PCC.

We extend the well known factorization theorems on the unit disk to prod- uct Hardy spaces, which generalizes the previous results obtained by Coifman, Rochberg and Weiss. The basic tools are the boundedness of a certain bilinear form on R2 + × R2 + and the characterization of BMO(R2 + × R2 +) recently obtained by Ferguson, Lacey and Sadosky.

Wilson’s disease (WD) is a disease of copper metabolism characterized by excessive copper deposition in the body. It is reported abnormal copper metabolism has been associated with cardiovascular disease. BNP and MMP2/9 were biomarkers of congestive heart failure (CHF). There is rare study to explore whether serum concentrations of BNP, MMP2, and or MMP9 are altered in patients with WD. In this study we determine whether serum concentrations of brain natriuretic peptide (BNP) and matrix metalloproteinases (MMP) 2 and 9 are increased in patients with WD. Serum BNP, MMP2 and MMP9 were measured by an ELISA in 34 patients with hepatic WD, in 68 patients with neurological WD, and in 33 healthy controls. We found serum BNP levels were higher in patients with neurological WD than in healthy controls (p = 0.033). Serum MMP2 levels were higher in patients with hepatic (p = 0.009) and neurologic (p = 0.0004) WD than in controls. Serum MMP9 levels were higher in patients with neurologic WD than in patients with hepatic WD (p = 0.002) and controls (p = 0.00005), and were higher in patients with hepatic WD than in controls (p = 0.03). Serum BNP levels were negatively correlated with ceruloplasmin (p = 0.017, r = −0.215), while serum (p = 0.019, r = −0.221) and MMP9 (p = 0.011, r = −0.231) in patients with WD were negatively correlated with ceruloplasmin. BNP, MMP2, and MMP9 may reflect the deposition of copper in the heart.

It was well known that Calderon–Zygmund operators T are bounded on H p for n n + e p ⩽ 1 provided T ∗ ( 1 ) = 0 . A new Hardy space H b p , where b is a para-accretive function, was introduced in [Y. Han, M. Lee, C. Lin, Hardy spaces and the Tb-theorem, J. Geom. Anal. 14 (2004) 291–318] and the authors proved that Calderon–Zygmund operators T are bounded from the classical Hardy space H p to the new Hardy space H b p if T ∗ ( b ) = 0 . In this note, we give a simple and direct proof of the H p − H b p boundedness of Calderon–Zygmund operators via the vector-valued singular integral operator theory.

Calcium carbonate particle attracts more and more attention because of its wide application in papermaking, rubbers, plastics and paints. In this paper, the CaCO3 particles were prepared by passing the mixed gas (CO2/N2) into CaCl2 solution. The effect of flow rate and CO2 content on the phase and morphology of precipitated CaCO3 was investigated with the help of SEM and XRD measurements. Both the results of SEM and XRD showed that more vaterite was formed at a high flow rate or high CO2 content, which was attributed to the slowing down of the transformation of vaterite to calcite. The change of pH and reaction time with the flow rate was also studied and the dissolution of carbon dioxide was analyzed.

In this paper, we prove the product H p boundedness of Calderon- Zygmund operators which were considered by Fefferman and Stein. The methods used in this paper are new even for the classical H p boundedness of Calderon- Zygmund operators, namely, using some subtle estimates together with the H p −L p boundedness of product vector valued Calderon-Zygmund operators.

It is well-known that Calderon-Zygmund operators T are bounded on Hp for $$\frac{n}{{n + 1}}< p \leqslant 1$$ provided T*(1) = 0. In this article, it is shown that if T*(b) = 0, where b is a para-accretive function, T is bounded from the classical Hardy space Hp to a new Hardy space H b p . To develop an H b p theory, a discrete Calderon-type reproducing formula and Plancherel-Polya-type inequalities associated to a para-accretive function are established. Moreover, David, Journe, and Semmes’ result [9] about the LP, 1 < p < ∞, boundedness of the Littlewood-Paley g function associated to a para-accretive function is generalized to the case of p ≤ 1. A new characterization of the classical Hardy spaces by using more general cancellation adapted to para-accretive functions is also given. These results complement the celebrated Calderon-Zygmund operator theory.

NiCo 2 O 4 spinel oxide was prepared through the hydroxide coprecipitation method. The NiCo 2 O 4 powders were analyzed by TGA, XRD, BET, SEM, and EDS. And the electrocatalytic properties of NiCo 2 O 4 /Ni electrode for oxygen evolution in alkaline solution were evaluated by cyclic voltammetry, roughness factor, Tafel curves and stability testing. The result shows that the preparation temperature can affect the formation, specific surface area, morphologies, and electrocatalytic properties of NiCo 2 O 4 spinel oxide. It is also found that NiCo 2 O 4 /Ni electrode prepared at 300°C has better electrocatalytic properties in oxygen evolution reaction than those prepared at other temperatures.

In this paper, the authors establish the inhomogeneous Plancherel–Pôlya inequalities on spaces of homogeneous type by use of the inhomogeneous discrete Calderón reproducing formulas. As an application, the authors prove that the Lebesgue norms of the inhomogeneous Littlewood–Paley g-function and S-function on spaces of homogeneous type are equivalent. All results are new even for ℝn.

Ni–Co spinel oxide was synthesized via the coprecipitation method. Hydroxide, carbonate, and oxalic acid were used as precipitants in order to compare their effect on the physicochemical properties and electrocatalytic properties of oxide. The result shows that hydroxide coprecipitation method can prepare Ni–Co spinel oxide with specific surface area of 67.19 m2/g, and the oxide has the best electrocatalytic behaviors in contrast to the oxide prepared by the other two precipitants.

A porous silica composite was prepared by the resin-impregnated method with natural clay and silica as the starting materials. Its compressive strength is up to 1.59 MPa when the mass-blending ratio of silica and clay is 3/7. The effect of silica addition on product strength was significantly investigated.

By depositing Mg vapor generated via carbothermal reduction on boron powder in the presence of different additives, dumbbell-like MgO nanofibers, NaCl particle-decorated MgO nanofibers and camphor tree stalk-like MgO fibers were produced. SEM, TEM and EDS analysis showed that the additives of Si and NaCl deposited in the sites of stacking faults in fiber, which resulted in the growth of different morphologies of decorated fibers.

An alumina foam with two kinds of pores was prepared by combining the sponge method and the pore-former method. The large pores were provided by the sponge method, and their sizes were in the range of 1–2 mm. The small pores were produced by the pore-former method with size in the micrometer range. The large pores offered a high porosity while the small pores offered a large surface area. The strength of samples sintered at different temperatures was measured, and the effect of sintering temperature on foam strength was analyzed by discussing porosity and grain bonding area. The sample sintered at 1550 °C has a compressive strength of 1.3 MPa and a porosity of 86%.

By depositing Mg vapor generated by carbothermal reduction onto boron powder, dumbbell-shaped MgO nanowhiskers were obtained. The diameters of these whiskers and balls are 50–150 nm and 1.4–2 μm, respectively. EDS analysis results reveals that the compositions of whiskers are Mg, O and small amount of B and Si. While the compositions of balls are Si, O and small amount of Al, B, C, Mg, K, Ca. SEM and TEM observation indicates that interfaces between balls and whiskers are very smooth. Experimental result shows that whiskers should grow in advance, and then balls grew by depositing silicon oxide and other vapor species onto the surface of these whiskers. The presence of silicon oxide was considered to play a key role in the formation of this peculiar morphological product.

The effect of sintering temperature on porous silica composite strength was studied by discussing three factors, namely crystal phase, glassy phase and porosity. The fired products of clay and silica are composed of crystalline phase and glassy phase. The crystalline phases consist of alpha-quartz and mullite and the glassy phase contains a disordered silica network. With the increase of sintering temperature up to 1360°C, the crystalline silica decreased gradually. The disappearing silica dissolved into the glass and became a part of glass network and resulted in the enhancement of glass strength. This change in glass played an important role in the improvement of sample strength. At the same time, the increase of sintering temperature promoted the densification of samples and reduced the porosity of products, which also contribute to the increase of sample strength. When the sintering temperature is up to 1390°C, the silica in glass tended to convert to cristobalite with the expansion of glassy phase. This expansion weakened the connection of atoms in glass network and brought some closed pores into products, which led to the decrease of sample strength.

By using different Mg vapor sources, different diameters of MgO whiskers and sheets were obtained via different growth mechanisms. When the Mg vapor was generated by carbothermal reduction of MgO and C powder, small MgO nanowhiskers (50 nm in diameter) and nanosheets (700 nm in width and 60–80 nm in thickness) were formed via vapor–liquid–solid (VLS) and vapor–solid (VS) processes. When the Mg vapor was generated by thermal evaporation of Mg powder, large MgO whiskers (0.6–2 μm in diameter) and sheets (2.4 μm in width and 1.5 μm in thickness) were formed, and the growth process was dominated by the VS mechanism. Experimental results suggested that the difference of Mg vapor concentration in the reaction tube is possibly responsible for the difference of the size and growth mechanism of the products.

Collapse is the major problem in preparing macroporous ceramics by the polymeric sponge method. The contributions of slurry viscosity, slurry-solid loading and heating rate to collapse are analyzed. The viscosity of slurry should be the highest possible before this parameter prevents slurry entry to all parts of the sponge. Higher viscosity leads to more solid particles of α-Al2O3 being taken into the sponge and this is required to avoid collapse prior to and during sintering. Heating rate is another important factor controlling collapse. To maintain pore structure, a controlled slow heating at the beginning of sintering program is needed.

The cation distribution in the spinel ferrite system Ni x Mn 1− x Fe 2 O 4 (with x =0, 0.25, 0.5, 0.75 and 1) has been calculated analytically for the first time in the closed form as a function of thermodynamic parameters by making reasonable assumption. The manganese and nickel site occupancies show a nearly linear composition dependence. Trivalent iron occupancies reflect the transition from octahedral to tetrahedral sites. The calculated results are consistent with those from X-ray diffraction (XRD).

An idea to improve the strength of ceramic foams by controlling the sintering temperature was proposed in this paper. The effect of sintering temperatures on alumina foams strength was investigated by discussing three factors: shrinkage, porosity and grain size, which changed with sintering temperatures. When the sintering temperature increased from 1400 to 1500 °C, the samples shrunk increasingly and the porosity decreased from 89.5 to 86.75%, which lead to the alumina foams strength increased from 0.27 MPa (at 1400 °C) to 0.627 MPa (at 1500 °C). When the sintering temperature increased from 1500 to 1550 °C, the porosity changed a little but the grains of samples grew up and contacted more tightly which resulted in the improvement of foam strength. When the sintering temperature is up to 1600 °C, a few grains preferentially grew too large compared to other grains, which caused a little decrease of strength. Therefore, to get strong alumina foams, the sintering temperature of 1550 °C was suggested in our work.

Many systems benefit from the ability to autonomously signal the occurrence of damage. The development of smart polymer coatings on metals can address scientific challenges such as nondestructive detection of early corrosion to avoid further destruction of materials. Here, pH- responsive polymer coatings on metals such as steel, aluminum, magnesium, and copper alloys are reported. The defect areas of coatings can gradually exhibit strong fluorescence as the corrosion starts. Based on the fundamental understanding of electrochemical mechanisms in metal corrosion, the designed pH-responsive polymer coating is dormant before crack occurrence. However, the on-demand release of fluorescent molecules from nano-containersin coatings occurs as corrosion proceeds with increasing pH value by transformation into highly active fluorescence indication from the dormant state at the stage of corrosion commencement. The developed smart polymer coatings can report the corrosion caused by a coating failure which provides a new strategy for nondestructive corrosion detection.

Marcinkiewicz multipliers are [math] bounded for [math] on the Heisenberg group [math] , as shown by D. Müller, F. Ricci, and E. M. Stein. This is surprising in that these multipliers are invariant under a two-parameter group of dilations on [math] , while there is no two-parameter group of automorphic dilations on [math] . This lack of automorphic dilations underlies the failure of such multipliers to be in general bounded on the classical Hardy space [math] on the Heisenberg group, and also precludes a pure product Hardy space theory. ¶ We address this deficiency by developing a theory of flag Hardy spaces [math] on the Heisenberg group, [math] , that is in a sense “intermediate” between the classical Hardy spaces [math] and the product Hardy spaces [math] on [math] developed by A. Chang and R. Fefferman. We show that flag singular integral operators, which include the aforementioned Marcinkiewicz multipliers, are bounded on [math] , as well as from [math] to [math] , for [math] . We also characterize the dual spaces of [math] and [math] , and establish a Calderón–Zygmund decomposition that yields standard interpolation theorems for the flag Hardy spaces [math] . In particular, this recovers some [math] results of Müller, Ricci, and Stein (but not their sharp versions) by interpolating between those for [math] and [math] .

In this article a Littlewood-Paley theorem for a new kind of Littlewood-Paley g-functions over spaces of homogeneous type is presented. Based on it the authors establish inhomogeneous discrete Calderon reproducing formulas for spaces of homogeneous type, making use of Calderon-Zygmund operators.

The spinel ferrite system NiMnxFe2−xO4, with x=0, 0.2, 0.4, 0.6, 0.8 and 1, was prepared by the standard double sintering ceramic method. The cation distribution has been calculated analytically for the first time using X-ray diffraction combined with computer technology. The results show, with increasing manganese ion substitution, that both Ni2+ and Mn3+ ions predominately occupy the octahedral sites. This is consistent with their preference for large octahedral site energy. The concentration of Mn3+ ions in octahedral sites increases while that of Fe3+ ions decreases linearly.

A facile novel approach to synthesize the hexagonal zinc oxide microtubes is demonstrated at low temperature and normal pressure under a kind of soft aqueous solution method. Hexagonal-faceted ZnO tubes with length of 1 μm, diameter of 300 nm and shells thickness of 30 nm on average were synthesized by this new simple method. The SEM results indicate that the drying temperature played an important role on the formation of hexagonal ZnO microtubes. It was interesting to find that ZnO particles exhibited different morphologies on changing the reaction temperature. The growth mechanism is briefly discussed in this paper.

In this paaper we use the Calderon-Zygmund operator theory to prove an inhomogenous Calderon reproducing formula on spaces of homogeneous type with finite or infinite measures. Our formula is new even for classical spaces of homogeneous type such as the surface of the unit ball and then-torus inR n, compact Lie groups,C ∞-compact Riemannian manifolds, and the boundary of any bounded Lipschitz domain inR n.

The single crystal NiAl2O4 was prepared by a solid-state reaction. The change of its cation distribution with temperature was calculated by a modified thermodynamic equation by including a new parameter δ, which is a characteristic of nonconfiguration entropy. The calculated results showed that the degree of inversion for NiAl2O4 decreases with temperature, although the temperature dependence of cation distribution is very weak. This result was supported by X-ray diffraction measurement.

Protein microcapsules have received considerable attention as effective drug delivery carriers for the treatment of deadly diseases, such as cancer, in the biomedical field. Up to now, extensive efforts have been devoted to fabricate the protein microcapsules and several approaches have been developed. Suslick and co-workers used high-intensity ultrasound to make aqueous suspensions of proteinaceous microcapsules filled with water-insoluble liquids and demonstrated the chemical mechanism of their formation. Lu et al. fabricated protein capsules through protein adsorption at the surface of the organic droplets followed by evaporation of the organic solvent. Balabushevich et al. produced stable polyelectrolyte capsules by the layer-by-layer (LbL) assembling of biodegradable polyelectrolytes, dextran sulfate, and protamine on melamine formaldehyde (MF) microcores followed by core decomposition at low pH. Among the various routes, the sonochemical method has proved to be a simple and effective technique for fabricating protein microcapsules due to the convenient processing and experimental setup, significant saving in time, and excellent products. In addition, the hydrophobic drugs could be directly loaded into protein microcapsules by dissolving drugs in the oil phase before sonication. Magnetic nanoparticles (MNPs), especially iron oxide (Fe3O4) MNPs, also have shown great prospect in biomedical application due to their good biocompatibility, strong superparamagnetism, nontoxicity, and easy preparation proACHTUNGTRENNUNGcess.[20–28] Introducing Fe3O4 MNPs into the biocompatible protein microcapsules are of particular interest, because protein microcapsules functionalized with Fe3O4 MNPs would possess several attractive advantages from a pharmaceutical standpoint

Nickel aluminate spinels were prepared by solid-state reaction. Their lattice parameters (a 0 ) changed with preparation temperature, which was explained by cation distribution, vacancies formation, and cation entrance. When the preparation temperature increased from 1100° to 1200°C, a 0 decreased with temperature as the result of the uptake of Al 2 O 3 . After 1200°C, a 0 increased to temperature, which was attributed to some Ni 2+ exchange with tetrahedral sites and some vacancies occupancy by Ni 2+ and Al 3+ .

In this paper we use the Calderon-Zygmund operator theory to prove a Calderon type reproducing formula associated with a para-accretive function. Using our Calderon-type reproducing formula we introduce a new class of the Besov and Triebel-Lizorkin spaces and prove a Tb theorem for these new spaces.

A novel morphology of SiOx (x=1–2) nanowires was fabricated via a thermal evaporation method by heating pure silicon powder at 1373 K followed by depositing silicon vapor on a quartz-glass substrate which was coated with a catalyst precursor from a 0.005 M Fe(NO3)3 aqueous solution. At the deposition temperature, the catalyst particles aggregated and formed quasi-plates, from which a short Si rod grew outward on one side and a great deal of SiOx nanowires projected outward on the other side, forming comet-like objects with long tails. The diameters of the nanowires gradually decreased with an increase in the distance from the catalyst plate.