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In this work, a novel and simple optical fiber hot-wire anemometer based on single-walled carbon nanotubes (SWCNTs) coated tilted fiber Bragg grating (TFBG) is proposed and demonstrated. For the hot-wire wind speed sensor design, TFBG is an ideal in-fiber sensing structure due to its unique features. It is utilized as both light coupling and temperature sensing element without using any geometry-modified or uncommon fiber, which simplifies the sensor structure. To further enhance the thermal conversion capability, SWCNTs are coated on the surface of the TFBG instead of traditional metallic materials, which have excellent thermal characteristics. When a laser light is pumped into the sensor, the pump light propagating in the core will be easily coupled into cladding of the fiber via the TFBG and strongly absorbed by the SWCNTs thin film. This absorption acts like a hot-wire raising the local temperature of the fiber, which is accurately detected by the TFBG resonance shift. In the experiments, the sensor's performances were investigated and controlled by adjusting the inherent angle of the TFBG, the thickness of SWCNTs film, and the input power of the pump laser. It was demonstrated that the developed anemometer exhibited significant light absorption efficiency up to 93%, and the maximum temperature of the local area on the fiber was heated up to 146.1°C under the relatively low pump power of 97.76 mW. The sensitivity of -0.3667 nm/(m/s) at wind speed of 1.0 m/s was measured with the selected 12° TFBG and 1.6 μm film.

Nanog, a unique homeobox transcription factor, maintains self-renewal and pluripotency of embryonic stem cells by binding to nuclear factor κB proteins in order to inhibit their transcriptional and prodifferentiation activities. We previously reported that Nanog attenuated inflammatory responses in rat primary microglia cells stimulated by lipopolysaccharide. However, the effects of Nanog on another microglia cell type, BV-2 cells, are still unknown. In this study, we investigated whether Nanog attenuated inflammatory responses in lipopolysaccharide-stimulated BV-2 cells and found that Nanog significantly decreased the release of nitric oxide and the expression of inducible nitric oxide synthase at the mRNA and protein levels. The production of proinflammatory cytokines including tumor necrosis factor-α and interleukin-1β was also significantly inhibited by Nanog. Further, we observed that the transcriptional activity of nuclear factor κB was dramatically reduced by Nanog. These results suggest that Nanog may be a potential anti-inflammatory therapy for neurological diseases caused by persistent microglia activation.

on-line program download of in-vehicle ECU required to be implemented according to diagnostic protocol ISO15765. Now, it's short of convenient and flexible download tool, which is low-cost. For this problem, on-line downloader based on ISO15765 is designed in this paper. Strategy of downloader system is designed, three main function modules are illustrated in detail. Test and application results show that the designed downloader based on ISO15765 is effective and reliable.

The influence of tilted surfaces on the measurement of shape by spatial coherence profilometry is investigated. Based on theoretical analysis and experimental results, the systematic measurement error caused by surface tilt is determined. The systematic measurement error depends not only on the tilt angle but also on the parameters of the experimental setup. The theoretical analysis and the experiments show the similarities and differences between spatial coherence profilometry and white-light interferometry. We also suggest the conditions to obtain correct measurements by use of spatial coherence profilometry.

As an alternative to the conventional optical frequency comb technique, a spatial frequency comb technique is proposed for dispersion-free optical coherence depth sensing. Instead of generating an optical frequency comb over a wide range of time spectrum, we generate a spatial frequency comb by modulating the incident angle of a monochromatic plane wave with a spatial light modulator (SLM). The use of monochromatic light combined with the SLM enables dispersion-free depth sensing that is free from mechanical moving components.

The principle of unconventional holography, called coherence holography, is proposed and experimentally demonstrated for the first time. An object recorded in a hologram is reconstructed as the three-dimensional distribution of a complex spatial coherence function, rather than as the complex amplitude distribution of the optical field itself that usually represents the reconstructed image in conventional holography. A simple optical geometry for the direct visualization of the reconstructed coherence image is proposed, along with the experimental results validating the proposed principle. Coherence holography is shown to be applicable to optical coherence tomography and profilometry.

As an alternative to the conventional optical frequency scanning technique, an angular spectrum scanning technique is proposed for absolute interferometry. Instead of sweeping the optical frequency over a wide range of spectrum, we sweep the angular spectrum by changing the incident angle of a monochromatic plane wave with a spatial light modulator (SLM). The use of monochromatic light combined with the SLM enables dispersion-free absolute interferometry that is free from mechanical moving components.

Spatial coherence profilometry is a method for measurement of the geometrical form of objects. In addition to the two lateral coordinates x and y, it measures the longitudinal coordinate z. In this way the complete 3D description of the object's surface is acquired. The main piece of the presented method is a Michelson interferometer illuminated by a monochromatic spatially extended light source. The surface of the object whose geometrical form should be measured is used as one mirror of the Michelson interferometer. By moving of the measured object along the optical axis, the intereference is observable only if the object's surface occurs in the vicinity of the so-called reference plane. The reference plane is given by the position of the object mirror when the Michelson interferometer is balanced. The described effect follows from the form of the spatial coherence function originated by the spatially extended light source. If the intensity at the output of the interferometer is recorded as a function of the position of the measured object, a typical correlogram arises. This correlogram is similar to that known with white-light interferometry. From the maximum of the correlogram, the z coordinate of the object's surface can be determined. Usually a CCD camera is used as the detector at the output of the Michelson interferometer. Then z coordinates of many surface points are parallel measured in the course of one measurement procedure and the 3D description of the object's surface is acquired. The scanning in the lateral direction is not necessary. Thus the described method provides a spatial coherence analogy to white-light interferometry which is based on temporal coherence. Unlike white-light interferometry, the described method does not require a broadband light source, the interferometer is illuminated by a monochromatic light source, usually a laser.

We review the principle and the applications of unconventional holography, called coherence holography 1,2 , which we recently proposed as a general technique for the synthesis and the control of 3-D spatial coherence function. An object recorded in a hologram is reconstructed as the three-dimensional distribution of a complex spatial coherence function, rather than as the complex amplitude distribution of the optical field itself that usually represents the reconstructed image in conventional holography. We introduce a newly proposed simple optical geometry for the direct visualization of the reconstructed coherence image, along with the experimental results validating the proposed principle. We also show that coherence holography has potential applications in optical coherence tomography and profilometry 3 as well as in basic science of coherence vortices 4 .

Based on the fringe formation in the k-vector space, we proposed an angular spectrum scanning technique for absolute interferometry. Instead of sweeping the optical frequency over a wide range of spectrum, we tune the angular spectrum by changing the incident angle of a monochromatic plane wave with a spatial light modulator (SLM). In the experiment, we built an equivalent spatially incoherent "ring source" to realize the angular spectrum scanning, and applied an algorithm to compensate the offset fluctuation of the fringe intensity.

A technique of imaging with a spatial coherence function, referred to as coherence holography, is proposed. A hologram of a three-dimensional object is recorded with coherent light in the same manner as in conventional holography, but the hologram is illuminated with spatially incoherent light to reconstruct the object as the three-dimensional distribution of a spatial coherence function, rather than as the amplitude or the intensity distribution of the optical field. A simple optical geometry for direct visualization of the reconstructed coherence image is proposed, and the results of preliminary experiments of a computer-generated coherence hologram (CGCH) are presented, which demonstrate the potential of CGCH as a means for optical coherence tomography and profilometry.

In summary, we have presented evidence of coherence vortices for the first time and experimentally investigated the properties of phase singularities in the coherence function. Unlike for conventional optical vortices, the intensity for coherence vortices does not vanish, but their contrasts become zero. Furthermore, the proposed method for synthesizing coherence vortices faciliates direct observation of the detailed local properties of an coherence vortex, and introduces new opportunities to explore other topological phenomena for the coherence function.

A simple technique for the direct full field observation of 3-D spatial coherence function with the capability of variable scale adjustment is proposed. Experimental results are presented to demonstrate the validity of the proposed method.

By controlling the irradiance of an extended quasi-monochromatic, spatially incoherent source, the evolution of the coherence vortices with the fractional topological phase variations has been investigated theoretically and experimentally. Article not available.

By controlling the irradiance of an extended quasimonochromatic, spatially incoherent source, an optical field is generated that exhibits spatial coherence with phase singularities, called coherence vortices. A simple optical geometry for direct visualization of coherence vortices is proposed, and the local properties and the spatial evolution of coherence vortex are experimentally investigated. To our knowledge, this is the first direct and quantitative experimental measurement of a generic coherence vortex.

By controlling the irradiance of an extended quasi-monochromatic, spatially incoherent source with a spatial light modulator, we generated a special optical field that exhibits a high degree of coherence with phase singularities for a specific pair of points at specified locations along the axis of beam propagation. Some local properties associated with coherence vortices, such as the Berry anisotropy ellipse describing the anisotropic degree of coherence close to a vortex core and the Dennis angular momentum rule for its associated phase, are also investigated experimentally.

An interferometer based on the spatial coherence detection has been developed for absolute height measurement. The location of a coherence peak resulting from the illumination of an extended quasi-monochromatic spatially incoherent light source with zone-plate-like spatial structure gives the longitudinal depth information. Besides simplifying the control of the light source structure, LCD-SLM eliminates the mechanical movement. Experiments of step height detection and profilometry of an object with a rough surface are presented that demonstrate the validity of the principle.

We address the basic issue of the observation condition in a synthetic coherence function applied to optical tomography and profilometry, which has not been made clear in previous papers. We present a more general theory for interference fringe formation for spatial coherence control with a synthetic source. The generalized theory predicts the existence of the observation condition that can make the measurement insensitive to the tilt of the object, which will open the new possibility of measuring objects with rough surfaces. We present experimental results that quantitatively verify the validity of the principle and the prediction.

A new scheme for synthesizing three-dimensional longitudinal spatial coherence function is proposed. By manipulating the irradiance of an extended quasi-monochromatic spatially incoherent source with a spatial light modulator, we generated a special optical field that exhibits high coherence selectively for the specified location along the optical axis of propagation and for the specified inclination between the two mirrors in the interferometer. The feasibility of the proposed principle is demonstrated by measuring a step height made by standard gauge blocks. The proposed scheme permits one to perform phase shift without recourse to mechanical movement. The quantitative experimental proof of the principle is presented.

A new method of spatial coherence profilometry is demon- strated. The surface profile is measured by shifting the spatial degree of coherence gradually in its own space of existence, and modulating its phase angle. In each point of the sample we analyze the change of light intensity versus the phase of a Fresnel zone pattern used as the intensity distribution of an incoherent quasimonochromatic source. The tilt of the surface is measured by gradually shifting the Fresnel zone plate on its transverse plane. This shift of the light source rotates the spatial degree of coherence around the coordinate origin until the condition of maximum interference visibility is fulfilled. The method works without any mechani- cal movement and a quasimonochromatic light illuminates the interfero- metric system. Experimental demonstration of the new method is pre- sented. © 2003 Society of Photo-Optical Instrumentation Engineers.

The principle and the applications of a recently proposed unconventional holography technique, coherence holography, applied for coherence vortex generation, and a related technique for dispersion-free 3-D coherence imaging based on a spatial frequency comb will be reviewed. (Digital Holography and Three-Dimensional Imaging, 2008)

2006