DSM (United States)

We recently reported that a targeted, brightly fluorescent gallium corrole (HerGa) is highly effective for breast tumor detection and treatment. Unlike structurally similar porphryins, HerGa exhibits tumor-targeted toxicity without the need for photoexcitation. We have now examined whether photoexcitation further modulates HerGa toxicity, using multimode optical imaging of live cells, including two-photon excited fluorescence, differential interference contrast (DIC), spectral, and lifetime imaging. Using two-photon excited fluorescence imaging, we observed that light at specific wavelengths augments the HerGa-mediated mitochondrial membrane potential disruption of breast cancer cells in situ. In addition, DIC, spectral, and fluorescence lifetime imaging enabled us to both validate cell damage by HerGa photoexcitation and investigate HerGa internalization, thus allowing optimization of light dose and timing. Our demonstration of HerGa phototoxicity opens the way for development of new methods of cancer intervention using tumor-targeted corroles.

Integration of THz quantum cascade lasers (QCLs) with single-mode 75 μm x 37 μm rectangular waveguide components, including horn antennas, couplers, and bends, for operation at 3 THz has been designed and fabricated using thick gold micromachining. Measurements on the isolated waveguide components exhibit fairly low loss and integration with THz QCLs has been demonstrated. This technology offers the potential for realizing miniature integrated systems operating in the 3 THz frequency range.

The design and optimization of realistically extended multi-quantum-well GaN-based light emitting diodes requires a quantitative understanding of the quantum mechanics-dominated carrier flow. Typical devices can be characterized by spatial regions of extremely high carrier densities such as n-GaN/p-GaN layers and quantum wells coupled to each other by tunneling and thermionic emission-based quantum transport. This work develops a multi-scale model that partitions the device into different spatial regions where the high carrier domains are treated as reservoirs in local equilibrium and serve as injectors and receptors of carriers into the neighboring reservoirs through tunneling and thermionic emission. The nonequilibrium Green's function (NEGF) formalism is used to compute the dynamics (states) and the kinetics (filling of states) in the entire extended complex device. The local density of states in the whole device is computed quantum mechanically within a multi-band tight binding Hamiltonian. The model results agree with experimental I-V curves quantitatively. Our results indicate tunneling to be a major contributor to the total charge current in LEDs.

A detailed understanding of noise characteristics is essential for the design of a high signal-to-noise ratio (SNR) reader sensor. We intend to correlate the microstructure to the source of magnetic noises for improving the magnetic stability of the recording heads. A dynamic magnetic sensitivity mapping (MSM) system is designed to image the magnetic noise sources in sub-micrometer sized recording heads. A nanometer sized magnetic force microscopy (MFM) tip was used to apply a well-defined, localized magnetic field on the air bearing surface (ABS) of the head. For a certain area position of the free layer with incoherent rotation of the magnetic moment, this localized magnetic field will cause magnetic instability in the head, and this instability will show up as electrical noise on the output signal. Because most of the noise related to magnetic domain fluctuation is dominated at the low frequency region, our study concentrates on the spatial characterization of the noise source in a frequency range of 20 kHz to 60 kHz. Recording the average amplitude of the noise spectrum due to the excitation in the measured frequency range as a function of the tip's position, the location of the magnetic noise source can be identified. Magnetic noise images have been obtained by our system for some recording giant magnetoresistance (GMR) and tunnel magnetoresistance (TMR) recording heads. Noise MSM images of some unstable recording heads clearly show the spatially uneven noise.

We briefly review the main stylized facts observed in financial markets and show how a multifractal process naturally captures those effects. In particular we generalize the construction of the multifractal random walk (MRW) due to Bacry, Delour and Muzy to take into account the asymmetric character of the financial returns. We show how one can include in this class of models the observed correlation between past returns and future volatilities, in such a way that the scale invariance properties of the MRW are preserved. Explicit scaling exponents are computes and are shown to behave differently for even and odd moments. We illustrate the usefulness of this "skewed" MRW by computing the resulting shape of the volatility smiles generated by such a process. A large variety of smile surfaces can be reproduced.

The communication architecture for most pointing, tracking, and high order adaptive optics control systems has been based on a centralized point-to-point and bus based approach. With the increased use of larger arrays and multiple sensors, actuators and processing nodes, these evolving systems require decentralized control, modularity, flexibility redundancy, integrated diagnostics, dynamic resource allocation, and ease of maintenance to support a wide range of experiments. Network control systems provide all of these critical functionalities. This paper begins with a quick overview of adaptive optics as a control system and communication architecture. It then provides an introduction to network control systems, identifying the key design areas that impact system performance. The paper then discusses the performance test results of a fielded network control system used to implement an adaptive optics system comprised of: a 10KHz, 32x32 spatial selfreferencing interferometer wave front sensor, a 705 channel "Tweeter" deformable mirror, a 177 channel "Woofer" deformable mirror, ten processing nodes, and six data acquisition nodes. The reconstructor algorithm utilized a modulo-2pi wave front phase measurement and a least-squares phase un-wrapper with branch point correction. The servo control algorithm is a hybrid of exponential and infinite impulse response controllers, with tweeter-to-woofer saturation offloading. This system achieved a first-pixel-out to last-mirror-voltage latency of 86 microseconds, with the network accounting for 4 microseconds of the measured latency. Finally, the extensibility of this architecture will be illustrated, by detailing the integration of a tracking sub-system into the existing network.

We present a system for intelligent machine fault detection and analysis. This system examines the signals in real-time, determines the quality of the signature for the entire set of signals and evaluates the error states of these signal combinations or signatures. This approach of continually evaluating quality of signals allows for predictive maintenance of the manufacturing system. The signals from the manufacturing system are obtained in a standard, optically isolated interface, the signals into this Remote Observation Manufacturing Equipment (ROME) system is processed and evaluated in real-time and history of these signals is stored. This system allows for the monitoring of signals in a continuous manner and these signals are recorded till a fault occurs. The graphical user interface provides user visualization control of the full family of signals at various time instants. These analog and digital signals are synchronized with the color images from two cameras and can be viewed with this GUI. The user can review both error and normal condition state using this interface.

“Geometrical Scaling” of MOS transistors supported the growth of the electronics industry for over 25 years (1975~2000) in accordance with Moore’s Law. The NTRS identified in the mid-90s major upcoming material and structural limitations of the silicon-gate transistor. To solve these problems the ITRS was formed in 1998 and the concepts of strained silicon, high-κ/metal gate, FinFET, and introduction of other semiconductor materials under “Equivalent Scaling” were identified as possible solutions to overcome these limitations. By 2011 all these new innovative technologies had been introduced into manufacturing. This approach has giving the semiconductor industry another 25 years (2000~2025) of growth. Realization of continuously smaller horizontal (2D) features will reach fundamental limits by ~2025. Flash producers have already transformed the realization of transistors from the horizontal dimension to the vertical dimension to solve this problem. Logic producers will follow. IRDS assessed that “3D Power Scaling” will extend Moore’s Law for at least another 15 years (2025~2040). How would implementation of 3D transistor and circuit affect lithographic requirements?

A readily automated procedure for testing and calibrating the wavelength scale of a scanning hyperspectral imaging camera is described. The procedure is a laboratory calibration method and it uses the absorbance features from a commercial didymium oxide filter as a wavelength standard. The procedure was used to accurately determine the pixel positions. An algorithm was developed to determine the center of the wavelength for any given abscissa accurately. During this investigation we determined that the sampled pixels show both trend and serial correlation as a function of the spatial dimensions. The trend is more significant than the serial correlation. In this paper, the trend will be filtered out by modeling the trend using an efficient global linear regression model of different order for different spectral band. The order is selected automatically and different criteria for selecting the order are discussed. Experimental results will be discussed.

The Ocean Color Instrument on NASA’s PACE mission is a 322-887nm hyperspectral imager with 1km x 1km nadir spatial resolution and 5nm spectral resolution utilizing charge-coupled devices (CCDs) operating in Time Delay Integration (TDI) mode where each TDI column represents a different wavelength in 0.625nm increments. After TDI, the charge is moved into serial output pixels and read out. The spatial resolution requires an 8.5MHz readout rate. This only allows 59ns for the CCD reset and video to be asserted and settled before sampling. The response exhibits serial pixel-to-pixel readout interference due to the lack of full settling. Each serial pixel value has a dependence on the value of the preceding pixel value. This leads to a spectrally dependent radiometric measurement error of up to 0.3%. We explain the operation of the detection system, the behavior of the interference, and show the resulting measurement error based on data from both ground testing and on-orbit characterization.

At present the Cable Act of 1984 and FCC Rules and policies preclude most telephone conipanies (telcos) from establishing any business or financial relationship (other than that of carrier—user) with a cable contpany serving the telco's franchise area. Exceptions to this proscription are available for rural telcos, i.e. those serving communities of 2,500 persons or less. In addition, waivers may be obtained if it can be demonstrated that independent cable service (service unaffiliated with the telco) is not feasible or for other good cause •

Using a laser with a beamsplitter and a lenseless video camera, the optical axis and true focus of a 16mm camera and lens is determined. The laser is spatially filtered and aimed through the beamsplitter into the camera lens. The return reflection from the film through the lens is observed on a video camera looking into the beamsplitter. The observed return beam converges when the lens is focused. The maximum intensity spot seen by the video camera is the mirror image of the pinhole in the laser spatial filter. Calibration targets can then be placed at the true object plane. The slightly defocused interference pattern can be used to determine the alignment and centering of the lens/camera system. The result is shown to be an improvement in the quality of the analysis results from the camera used for measurement of high speed motion.

Light-Emitting Diodes (LEDs) exhibit a typical Lambertian emission, usually requiring reshaping by means of secondary optics. We review the potential of various integrated photonic architectures to address the demand for system miniaturization and high efficiency in emerging applications. Photonic structures that can be potentially integrated in LED devices include metalenses, photonic crystals and reflective metasurfaces. We embed periodic nanoantennas in InGaN/GaN multi-quantum well (MQW) LEDs to control their far-field emission directionality and enhance collection efficiency. We propose exploiting mechanisms such as surface lattice resonances, which rely on the near-field coupling between the quantum wells and the nanoantenna array. Multiple experimental and modeling studies demonstrate the benefits and challenges of optimized integrated metasurfaces to enable efficient SSL sources without the need of bulky secondary optics for directional beam control.

When a tennis ball strikes a racket the impact causes vibrations which are distracting and undesirable to the player. In this work a passive damping system used to reduce vibration is described. The damping system uses a viscoelastic material along with a stiff composite constraining layer which is molded on the inner surface of the tennis racket frame. When a ball strikes a racket with this damping system the vibration causes shearing strain in the viscoelastic material. This strain energy is partially dissipated by the viscoelastic material, thereby increasing the racket damping. An analysis of the design was performed by creating a solid CAD model of the racket using Pro/Engineer. A finite element mesh was created and the mesh was then exported to ANSYS for the finite element modal analysis. The technique used to determine the damping ratio is the modal strain energy method. Experimental testing using accelerometers was conducted to determine the natural frequency and the damping ratio of rackets with and without the damping system. The natural frequency of the finite element model was benchmarked to the experimental data and damping ratios were compared. The modal strain energy method was found to be a very effective means of determining the damping ratio, and the frequencies and damping ratios correlated well with the experimental data. Using this analysis method, the effectiveness of the damping ratio to the change in key variables can be studied, minimizing the need for prototypes. This method can be used to determine an optimum design by maximizing the damping ratio with minimal weight addition.