Search

In the present work, the sub-micrometer containers were prepared using mesoporous silica particles (SBA-15) with parallel channels as reservoir and 8-hydroxyquinoline as corrosion inhibitor. Layer-by-layer assembling was used to construct a shell of polyelectrolytes around the silica particles. Release of 8-hydroxyquinoline from sub-micrometer containers was studied in response to acidic or alkaline pH values. The results of electrochemical impedance spectroscopy (EIS) show the improvement of corrosion resistance of epoxy coatings containing sub-micrometer containers. Self-healing ability of the epoxy coatings was provided by sub-micrometer containers, as evidenced by the results of scanning vibrating electrode technique (SVET).

In a previous article, it was reported that a rather amount of sulfate end-groups as initiator fragment were buried in the inside of polystyrene (PS) particles, which were synthesized by emulsion polymerization with potassium persulfate initiator and nonionic emulsifier and operated to absorb water from the aqueous medium, resulting in hollow particles, when the PS emulsion was treated at higher temperature than the glass transition temperature of PS. In this article, it was clarified that the water absorption is based on the osmotic pressure between the outside (aqueous medium) and inside of the PS particles due to the buried sulfate end-groups.

Determining the structural chirality of biomolecules is of vital importance in bioscience and biomedicine. Conventional methods for characterizing molecular chirality, e.g., circular dichroism (CD) spectroscopy, require high-concentration specimens due to the weak electronic CD signals of biomolecules such as amino acids. Artificially designed chiral plasmonic metastructures exhibit strong intrinsic chirality. However, the significant size mismatch between metastructures and biomolecules makes the former unsuitable for chirality-recognition-based molecular discrimination. Fortunately, constructing metallic architectures through molecular self-assembly allows chirality transfer from sub-nanometer biomolecules to sub-micrometer, intrinsically achiral plasmonic metastructures by means of either near-field interaction or chirality inheritance, resulting in hybrid systems with CD signals orders of magnitude larger than that of pristine biomolecules. This exotic property provides a new means to determine molecular chirality at extremely low concentrations (ideally at the single-molecule level). Herein, three strategies of chirality transfer from sub-nanometer biomolecules to sub-micrometer metallic metastructures are analyzed. The physiochemical mechanisms responsible for chirality transfer are elaborated and new fascinating opportunities for employing plasmonic metastructures in chirality-based biosensing and bioimaging are outlined.

Resolving the heterogeneity of particle populations by size is important when the particle size is a signature of abnormal biological properties leading to disease. Accessing size heterogeneity in the sub-micrometer regime is particularly important to resolve populations of subcellular species or diagnostically relevant bioparticles. Here, we demonstrate a ratchet migration mechanism capable of separating sub-micrometer sized species by size and apply it to biological particles. The phenomenon is based on a deterministic ratchet effect, is realized in a microfluidic device, and exhibits fast migration allowing separation in tens of seconds. We characterize this phenomenon extensively with the aid of a numerical model allowing one to predict the speed and resolution of this method. We further demonstrate the deterministic ratchet migration with two sub-micrometer sized beads as model system experimentally as well as size-heterogeneous mouse liver mitochondria and liposomes as model system for other organelles. We demonstrate excellent agreement between experimentally observed migration and the numerical model.

Colloidal coordination compounds in the sub-micrometer range were synthesized from a chloro gold(I) carbene complex via the anti-solvent procedure and stabilized by a surfactant shell of Tween 20. This compound was successfully applied as model system to monitor heterogeneous multiphase ligand substitution reactions at the solid-liquid interface.

In this work, photoanodes with sub-micrometer cavities of different sizes and ratios were easily fabricated by burning off the polystyrene sub-micrometer spheres (PSSs) embedded in TiO 2 paste. When the original PSS in the anode was 500 nm in diameter and the ratio was 100 μl (5 vol%) PSSs solution mixed with 0.1 g TiO 2 nanoparticles, the optimized performance of the fabricated dye-sensitized solar cells (DSSCs) was remarkably ∼48% higher than that of pristine TiO 2 DSSCs without sub-micrometer cavities in control group. This great performance improvement was attributed to the ability of enhancing light scattering and maintaining low resistance with the introduction of optimized amount of sub-micrometer cavities. This general strategy should help to design and develop the future DSSCs with better performance.

However, one shortcoming is that it requiresrather long reaction time, namely 3 d, to achieve narrow sizedistribution, which hampered the practical use of the syn-thetic method. Therefore, we have been seeking for morefacile methods that can shorten the reaction time of theabove-mentioned synthetic method. One of the possibleways to achieve the goal might be the use of surfactants tonarrow the size distribution. Among many candidates,Pluronic

Although manufactured nanomaterials have a great many of fantastic functions，the adverse impacts about them have been observed. As a kind of nanomaterial, biomedical films obtained from electrospinning are valued greatly, and the sizes of the diameters in electrospun films plays a fundamental role in enhancing the safety of films. When the diameter of fibers increased to hundreds of nanometers, it will become difficult for fibers to diffuse and infiltrate into human’s body, and then the security of the biomedical films is enhanced greatly. In our work, high viscosity polymer and high viscosity solution are electrospun to increase the diameter of fibers. Besides, melt-eletrospinning is introduced as an alternative candidate for improving the security of biomedical films, especially no poisonous solvent exists.

Microscopic X-ray fluorescence (micro-XRF) is a versatile tool in environmental analysis. We review work done in this field from 2008 to 2010 and highlight new aspects. Overall, there is a strong trend to combine fluorescence data with other data like diffraction or absorption spectroscopy. Also, the use of laboratory based instrumentation has become wide spread as more commercial instruments are available. At laboratories and synchrotron sites the trend towards higher spatial resolution is still persistent hitting sub micrometer values in case of synchrotron set ups.

The bottom-up filling of electroless copper usually depends on inhibiting the Cu deposition at the surface or accelerating the Cu deposition in the bottom of trenches to achieve a relative high deposition rate of electroless copper in the bottom of trenches. In this paper, a complete bottom-up filling of electroless copper, in which the deposition rates of the electroless copper were not only inhibited at the surface of the substrate, but also were accelerated in the bottom of the trenched, was designed and achieved in the plating bath with an addition of bis (3-sulfopropyl) disulfide (SPS) and polyethylene glycol (PEG). The cross-sectional SEM observation of trenches indicated that all trenches with different widths ranging from 100 to 290 nm were filled completely by electroless copper, and no void was found. This was attributed to three factors, the electroless Cu deposition was accelerated markedly by an addition SPS only; but it was suppressed sharply by a combination addition SPS and PEG-4000; the large molecular weight and lower diffusion coefficient of PEG-4000 resulted in concentration gradient of PEG-4000 in the trenches. The effects of PEG-4000 and SPS on the polarization behaviors of the electroless copper plating bath were investigated by the linear sweep voltammetry method and mixed potential theory.

Fine-structured ZnO patterns with sub-micrometer based on a replication method was fabricated. A replication method was used mixtures of polyvinyl alcohol (PVA) and ZnO nanosized particles in water. The mixtures were then filled in a quartz mold with different pattern sizes and dried at room temperature. After the drying, the PVA and ZnO dried film was detached from the mold. Through burn-out at various sintering temperatures, ZnO patterns with line and space patterns as smalls as sub-micrometer in size were successfully fabricated. The results demonstrated possibilities to produce inorganic materials with various compositions and structures with a facile approach and a simple method.

Sub-micrometer-sized tungsten-whisker arrays are synthesized by a catalyst- and template-free vapor-deposition process. The resultant whiskers have a hexagonal cross-section, sharp pyramidal tip, and large aspect ratio. The excellent field-emission properties of the whisker arrays, which can be tuned varying the diameters of the synthesized whiskers, are demonstrated.

Immunomodulatory effects of chemicals adsorbed to particles with aerodynamic diameter below 0.49 microm (PM(0.5)) collected in winter 2001 at three sampling points (industrial area [LPIn], traffic-influenced urban area [LPCi], and control area [LPCo]) of La Plata, Argentina, were investigated. The sampling of particulate matter was carried out with high-volume collectors using cascade impactors. PM(0.5)-adsorbed compounds were hexane-extracted by accelerated solvent extraction. For immunological investigations, human peripheral blood lymphocytes were activated by phytohemagglutinin and exposed to dimethyl-sulfoxide dilutions of PM(0.5)-extracts for 24h. Vitality/proliferation was quantified using MTT, released interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) by ELISA. Cytokine production but not vitality/proliferation was significantly suppressed by all of the highest extract concentrations. Generally, suppression of IFN-gamma by PM(0.5)-extracts was stronger than those of IL-4. Based on administered mass of PM(0.5), all extracts suppressed IFN-gamma production nearly uniform. Contrary, LPCi-extracts exerted maximum IFN-gamma suppression based either on air volume or regarding PM(0.5)-adsorbed PAH. Also the ranking of PM(0.5)-associated effects on IL-4 production differs in dependence of the chosen reference points, either mass or [microg/ml] or air volume [m(3)/ml] related dust quantities in cell culture. Based on the corresponding air volume, LPCi-extracts inhibited IL-4 production to the maximum extend, whereas suppression of IL-4 was comparable based on concentrations. This indicates that not only the disparate PM(0.5)-masses in air cause varying impacts, but also that disparities in PM(0.5)-adsorbed chemicals provoke different effects on immune responses and shifts in the regulatory balance that might have implications for allergy and cancer development.

We report on mobilities up to 3.6 cm 2 /V s in organic field-effect transistors (OFETs) with solution-processed dithiophene- and dibenzo-tetrathiafulvalene (DT- and DB-TTF) single crystals as active materials. In the devices, the channel length varies from 100 lm down to sub 100 nm, and the SiO2 thickness is either 100 nm, 50 nm, or 20 nm. The devices exhibit excellent operation characteristics with an on/off-ratio exceeding 10

Scanning electrochemical microscopy (SECM) is a powerful surface characterisation technique that allows for the electrochemical profiling of surfaces with sub micrometer resolution. While SECM has been most widely used to electrochemically study and profile non-biological surfaces and processes, the technique has in recent years, been increasingly used for the study of biological systems - and this is the focus of this review. An overview of SECM and how the technique may be applied to the study of biological systems will first be given. SECM and its application to the study of cells, enzymes and DNA will each be considered in detail. The review will conclude with a discussion of future directions and scope for further developments and applications.

We show that shot noise is a useful tool in studies of electron transport in hopping and resonant tunnelling between localised states. In resonant tunnelling through a single impurity we observe an enhancement of shot noise caused by Coulomb interaction between two resonant channels. In hopping along chains of localised states, shot noise is shown to be sensitive to the distribution of the barriers between the states and the Coulomb interaction between hopping electrons. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

In-situ heating in a transmission electron microscope was used to investigate the stress-relief mechanisms occurring in the 3–4 nm thick aluminum-oxide films present on the surfaces of submicron Al–11.6% Si powder particles during melting. Experimental observations show that the aluminum-oxide shell undergoes creep to relieve the high stress generated by the expanding liquid during melting. Surface oxides that contain defects do not undergo uniform creep and are prone to cracking, which causes ejection of some of the pressurized liquid inside the particles through the crack. Calculations were performed to estimate the stresses generated on the aluminum-oxide shell by the expanding liquid and the possible effect of the stress generated by the confining oxide shell on the melting temperature of the Al–Si alloy. The calculations show that the oxide film creeps to avoid the high tangential stress (on the order of 15 GPa) produced by the expanding liquid and that this creep mechanism prevents the oxide from markedly changing the melting behavior of the Al–Si particles.

A new type of tensile tester for sub-micrometer-thick films has been developed. The tester is has a grip that allows chucking one end of a thin-film specimen by electrostatic force while the other end is fixed to a silicon substrate. It uses a servo-controlled balance for small-force measurement. Sub-micrometer-thick single-crystal-silicon specimens were fabricated using bulk micromachining starting with a SIMOX wafer. The specimens were 0 to 300 µm long, 20 or 50 µm wide and 0.14 µm thick. The tensile strength ranged from 1.4 to 4.3 GPa for six samples; the longer the specimen the lower strength.

A strongly confined light field necessarily exhibits a local polarization that varies on a subwavelength scale. We demonstrate that a single optical mode of such kind can be used to selectively and simultaneously manipulate atomic ensembles that are less than a micron away from each other and equally coupled to the light field. The technique is implemented with an optical nanofiber that provides an evanescent field interface between a strongly guided optical mode and two diametric linear arrays of cesium atoms. Using this single optical mode, the two atomic ensembles can simultaneously be optically pumped to opposite Zeeman states. Moreover, the state-dependent light shifts can be made locally distinct, thereby enabling an independent coherent manipulation of the two ensembles. Our results open the route towards advanced manipulation of atomic samples in nanoscale quantum optics systems.

This paper describes a quick and simple method for the determination of the refractive index (RI) of very small particles by measuring the light intensity passing through a suspension of particles. Any commercial spectrophotometer and regular capillaries can be used. Since the RI of the liquid in which the particles are suspended can be prepared as requested, there are almost no limitations with respect to the range of the RI. The only limitations arise from the liquids that are available as well as their properties (e.g., viscosity, health risks). A Gauss-function describes the measured data that simplifies the determination of the RI of the mineral. Because the refractive index depends on the wavelength applied, the use of spectrophotometers allows for the determination of the variation of the RI at different wavelengths.

The historical development and present state of the art of scanning thermal microscopy (SThM) – temperature profiling, thermography and other measurements of thermal parameters – in the sub-μm range and the relevant thermal sensors are reviewed. The paper proposes a classification scheme for the various experimental arrangements of STM and AFM based SThM's. Limitations of the SThM technique and future prospects are briefly discussed.

Sub-micrometer length copper fibers are obtained via polymer supported electrospinning and subsequent thermal treatment. The copper nature of the fibers is confirmed by using energy- dispersive X-ray analysis and wide- angle X-ray analysis (see figure). The copper fibers show metallic conductivity as confirmed by conductance measurements in a low-energy electron point source microscope.

Measured output characteristics of our prepared short-channel organic transistor show the well known effect of a nonlinear increase of the drain current with positive curvature at low drain voltages. We investigated this peculiarity by means of 2D simulations considering the bilayer contact for source or drain, respectively. The simulations show that the low work function of the chromium adhesion layer causes the nonlinearity. Another important aspect demonstrated by the simulations is the estimation of the mobility applying the simple Shockley equation. The influence of the contact properties on the rise of the drain current results in erroneous values for the mobility as estimated directly from the current-voltage characteristics.

In this paper, the I-V characteristics of silicon n/sup +/-n/sup -/-n/sup +/ diode are investigated as a parameter of the length of the n/sup -/ region. This diode with shorter n/sup -/ region than 1 /spl mu/m has the ohmic characteristics until reaching high electric field in spite of the existence of numerous space-charges in the n/sup -/ region, for the first time in this report. This conductance of the diode is inversely proportional to the third power of the length of the n/sup -/ region. The experimental results are in good agreement with an analytical calculation including the diffusion term of carriers injected from the n+ regions to the n/sup -/ region. However, the diode with longer n/sup -/ region than 2 /spl mu/m shows the space-charge-limited conduction which is the same as earlier reports.

In this paper, a gas-liquid synthetic method has been used to prepare the carbonates for decreasing the size of the carbonate grain, optimizing the shape of the grain, lowering the complexity of preparing technology and improving the emission characteristics of the cathode. Fig.2 is the SEM of the carbonates which is synthesized under the condition of 0.125 mol/1 concentration, 2.51/min gas rate and 70°C temperature. The mole ratio of the carbonates' ingredient BaCO3:SrCO3:CaCO3 is (50%-58%): (38%-45%): (4%-8%). It can be seen that the grain of the carbonates is filamentous shape with less than 1μm diameter and 5~ 7μm length.

This article presents the ion beam etching technology for photonic crystal structures in lithium niobate. This new fabrication technique is able to create sub micrometer size elements in lithium niobate with a depth of up to 500 nm.

Evaporation of a spherically symmetric sub-micrometer size liquid droplet is studied using a diffuse interface hydrodynamic model supplemented by the van der Waals equation of state with parameters characteristic for argon. The droplet, surrounded by saturated vapor, is held in a container with the temperature of the walls kept fixed. The evaporation is triggered by a sudden rise of the temperature of the walls. Time and space evolution of the basic thermodynamic quantities is presented. The time and space scales studied range from picoseconds to microseconds and from nanometers to micrometers, respectively. We find that the temperature and chemical potential are both continuous at the interface on the scale larger than the interfacial width. We find that at long times the radius R of the droplet changes with time t as R(2)(t) = R(2)(0) - 2tkappa(v)(T(w) - T(l))/ln(l), where kappa(v) is the heat conductivity of the vapor, n(l) and T(l) are the density and the temperature of liquid inside the droplet, respectively, l is the latent heat of transition per molecule, and T(w) is the temperature of the ambient vapor.

We present an automated method for isolating pure bacterial cultures from samples containing multiple species that exploits the cell's own physiology to perform the separation. Cells compete to reach a chamber containing nutrients via a constriction whose cross-sectional area only permits a single cell to enter, thereby blocking the opening and preventing other cells from entering. The winning cell divides across the constriction and its progeny populate the chamber. The devices are passive and require no user interaction to perform their function. Device fabrication begins with the creation of a master mold that contains the desired constriction and chamber features. Replica molding is used to create patterned polymer chips from the master, which are bonded to glass microscope cover slips to create the constrictions. We tested constriction geometries ranging from 500 nanometers to 5 micrometers in width, 600 to 950 nanometers in height, and 10 to 40 micrometers in length. The devices were used to successfully isolate a pure Pseudomonas aeruginosa culture from a mixture that also contained Escherichia coli. We demonstrated that individual strains of the same species can be separated out from mixtures using red and green fluorescently-labeled E. coli. We also used the devices to isolate individual environmental species. Roseobacter sp. was separated from another marine species, Psychroserpens sp.

Fabrication de PMOSFET, de l'ordre du micrometre, par l'utilisation d'une technologie d'implantation double ion. Des PMOSFET avec des longueurs de canaux de 0,6 a 0,95 et des oxydes de grille de 21,5 nm sont fabriques par l'utilisation d'un procede pour MOSFET. Des transconductances maximum de 40 a 45 mS/mm sont obtenues pour l'implantation double en Ga/B et In/B

Spectroscopy in a thin cell of dilute vapour, with a sub-micrometer thickness (varying locally in a 50 nm - I μm range) offers interesting possibilities to probe the atom-surface interaction in an unexplored distance range.

We report on a technology for the fabrication of sub-micrometer sized cross-type Josephson tunnel junctions in niobium technology. We present the fabrication scheme and properties of cross-type junctions with linear dimensions from 10 down to 0.6??m. Sidewall passivation of the junctions is achieved by anodization as well as by planarizing the junctions with SiO in a self-aligned deposition step. The measured ratio of the sub-gap resistance to the normal resistance is about 35. Because of their low sub-gap current and low parasitic capacitance such junctions are well suited for applications like high resolution SQUIDs.

Utilizing the nano-machining technique developed the sub-micrometer oxide powder cathode. Put the sub-micrometer powder at the bottom next to the nickel disc was the best structure. The maximum cathode current ratio (ΔMIK%) is more than 78% after 3000 hrs of testing.

A K -theory urban dispersion model has been used with the St. Louis RAPS data base to calculate super- and sub-micrometer aerosol mass concentrations. The model calculations showed relatively good agreement in phase and magnitude with dichotomous sampler data for the time period studied. The calculated sub-micrometer aerosol mass concentrations gave a much better correlation with observed values of optical extinction than did the observational values from the RAPS dichotomous sampler network. It is found that even on the urban scale, the dry deposition velocity is an important parameter for modelling both the sub- and super-micrometer aerosol mass concentrations.

The use of biomimetic approaches toward the production of nonsolid yet functional architectures holds potential for the emergence of novel device concepts. Gels, in particular those obtained via self-assembly of π-conjugated molecules, are dynamic materials possessing unique (opto)electronic properties. Their adaptive nature imparts unprecedented responsivity to various stimuli. Hitherto, a viable device platform to electrically probe in situ a sol-gel transition is still lacking. Here we describe the fabrication of a sub-micrometer electrodic cavity, which enables low-voltage electrical operation of π-gels. Thanks to the in situ supramolecular self-assembly of the π-gelator occurring within the cavity, we conceived a novel gel-based memristor whose sol-gel transition is reversible and can be controlled via heating and dc bias. This work opens perspectives toward the fabrication of a novel generation of nonsolid multiresponsive devices.