gebhart/patrepeval huggingface dataset:
On-line determination of alloy composition during ternary III/V molecular beam epitaxy (1989)

We describe a simple, new method for deducing surface alloy composition during ternary III/V molecular beam epitaxy. The method is based on on-line reflection mass spectrometry of the group V flux ‘‘reflected’’ from the surface during momentary terminations of individual group III fluxes.
All-Optical Modulation in a Silicon Waveguide Based on a Single-Photon Process (2008)

All-optical, low-power modulation is a major goal in photonics. Because of their high mode-field concentration and ease of manufacturing, nanoscale silicon waveguides offer an intriguing platform for photonics. So far, all-optical modulators built with silicon photonic circuits have relied on either two-photon absorption or the Kerr effect. Both effects are weak in silicon, and require extremely high (~5 W) peak optical power levels to achieve modulation. Here, we describe an all-optical Mach-Zehnder modulator based on a single-photon absorption (SPA) process, fabricated entirely in silicon. Our SPA modulator is based on a process by which a single photon at 1.55 mum is absorbed and an apparently free-carrier-mediated process causes an index shift in silicon, even though the photon energy does not exceed that of silicon's bandgap. We demonstrate all-optical modulation with a gate response of 1deg/mW at 0.5 Gb/s. This is over an order of magnitude more responsive than typical previously demonstrated devices. Even without resonant enhancement, further engineering may enable all optical modulation with less than 10 mW of gate power required for complete extinction, and speeds of 5 Gb/s or higher.
A Study on Vehicle to Vehicle Communication Requirements for Safety Driving Support Systems (2005)

We are studying safety driving support systems that are attained by exchanging each vehicle's movement data through vehicle to vehicle (V-V) communication. This paper describes a study on the communication protocol. First, the design methodology for the physical and data link layer (L1 and L2) is described under an ideal condition, without restrictions in other words, because the basic specification of the communication system depends on these lower layer protocols. Next, points for applying it to a practical system are described.
Directional microphones for teleconferencing (1997)

Directional microphones are spatial filters that can be designed to improve the sound quality of speech in audio telecommunication. At present, the most common type of directional microphone utilized in audio telecommunication is a simple first-order differential microphone having a hypercardioid directivity pattern. The directivity index (microphone gain in isotropic noise) for the hypercardioid microphone is 6 dB. For very noisy and reverberant environments more directional gain will be necessary. This talk will describe and discuss some of the microphone array systems that have been proposed in the last decade that address this problem.
Design and Modeling of a Microscale Selective Laser Sintering System (2016)

The development of micro and nanoscale additive manufacturing methods in metals and ceramics is important for many applications in the aerospace, medical device, and electronics industries. Unfortunately, most commercially available metal additive manufacturing tools have feature-size resolutions of greater than 100 μm, which is too large to precisely control the microstructure of the parts they produce. A few research-grade metal additive manufacturing tools do exist, but their build rate is generally too slow for commercial applications. Therefore, this paper presents a new microscale selective laser sintering (μ-SLS) that can be used to improve the minimum feature-size resolution of metal additively manufactured parts by up to two orders of magnitude, while still maintaining the throughput of traditional additive manufacturing processes. In order to achieve this goal, several innovative design features like the use of (1) ultra-fast lasers, (2) a micro-mirror based optical system, (3) nanoscale powders, and (4) a precision spreader mechanism, have been implemented. The micro-SLS system is capable of achieving build rates of approximately 1 cm3/hr while achieving a feature-size resolution of approximately 1 μm. This paper will also present new molecular scale models that have been developed for the micro-SLS to quantify and certify the micro-SLS build process. Modeling of the micro-SLS process is challenging, because most macroscale models of the SLS process contain assumptions that are no longer valid when the size of the particles that are being sintered is smaller than the wavelength of the laser being used to sinter them. Therefore, in modeling the micro-SLS process we must account for the wave nature of light and can no longer rely on the ray tracing models commonly used to model the SLS process. Also, heat transfer in the micro-SLS process is dominated by near-field radiation due to the diffraction of the light off the nanoparticles in the powder bed and the ultrafast lasers that are used in the micro-SLS system. This means that the assumptions of heat transfer by conduction and far-field radiation in the macroscale SLS systems are no longer valid for the micro-SLS system. Finally, the agglomeration of nanoparticles in the powder bed must be accurately modeled in order to precisely predict the formation of defects in the final parts produced. Overall, the goal of this modeling effort is to be able to predict the quality of a part produced using any given processing conditions, in order to produce parts that are “born certified” and do not need to be tested post fabrication.
A complex role for the γ‐butyrolactone SCB1 in regulating antibiotic production in <i>Streptomyces coelicolor</i> A3(2) (2001)

Many streptomycetes produce extracellular gamma-butyrolactones. In several cases, these have been shown to act as signals for the onset of antibiotic production. Synthesis of these molecules appears to require a member of the AfsA family of proteins (AfsA is required for A-factor synthesis of the gamma-butyrolactone A-factor and consequently for streptomycin production in Streptomyces griseus). An afsA homologue, scbA, was identified in Streptomyces coelicolor A3(2) and was found to lie adjacent to a divergently transcribed gene, scbR, which encodes a gamma-butyrolactone binding protein. Gel retardation assays and DNase I footprinting studies revealed DNA binding sites for ScbR at - 4 to - 33 nt with respect to the scbA transcriptional start site, and at - 42 to - 68 nt with respect to the scbR transcriptional start site. Addition of the gamma-butyrolactone SCB1 of S. coelicolor resulted in loss of the DNA-binding ability of ScbR. A scbA mutant produced no gamma-butyrolactones, yet overproduced two antibiotics, actinorhodin (Act) and undecylprodigiosin (Red), whereas a deletion mutant of scbR also failed to make gamma-butyrolactones and showed delayed Red production. These phenotypes differ markedly from those expected by analogy with the S. griseus A-factor system. Furthermore, transcription of scbR increased, and that of scbA was abolished, in an scbR mutant, indicating that ScbR represses its own expression while activating that of scbA. In the scbA mutant, expression of both genes was greatly reduced. Addition of SCB1 to the scbA mutant induced transcription of scbR, but did not restore scbA expression, indicating that the deficiency in scbA transcription in the scbA mutant is not solely due to the inability to produce SCB1, and that ScbA is a positive autoregulator in addition to being required for gamma-butyrolactone production. Overall, these results indicate a complex mechanism for gamma-butyrolactone-mediated regulation of antibiotic biosynthesis in S. coelicolor.
Dye‐Modified Nanochannel Materials for Photoelectronic and Optical Devices (2008)

Abstract Artificial photonic antenna systems have been realised by incorporating organic dyes into zeolite L. The size and aspect ratio of the cylindrically shaped zeolite crystals can be tuned over a wide range, adding to the versatility of this host material. A 600 nm sized crystal, for example, consists of about 96 000 one‐dimensional channels oriented parallel to the cylinder axis. Geometrical constraints imposed by the host structure lead to supramolecular organisation of the guests, allowing high concentrations of non‐ or only very weakly interacting dye molecules. A special twist is added to these systems by plugging the channel openings with a second type of fluorescent dye, a so‐called stopcock molecule. The two types of molecules are precisely tuned to each other; the stopcocks are able to accept excitation energy from the dyes in the channels, but cannot pass it back. The supramolecular organisation of dyes in the zeolite channels corresponds to a first stage of organisation, allowing light‐harvesting within the volume of a cylindrical crystal and radiationless energy transport to either the cylinder ends or centre. The second stage of organisation represents the coupling to an external acceptor or donor stopcock fluorophore at the channel entrances, which can then trap or inject electronic excitation energy. The third stage of organisation is realised by interfacing the material to an external device through a stopcock intermediate. We observed that electronic‐excitation‐energy transfer in dye–zeolite L materials occurs mainly along the channel axis and we have shown that macroscopically organised materials can be prepared. The new materials offer unique possibilities as building blocks for optical, electro‐optical and sensing devices.
Multifunctional carbon nanotubes with nanoparticles embedded in their walls (2007)

Controlled amounts of nanoparticles ranging in size and composition were embedded in the walls of carbon nanotubes during a template-assisted chemical vapour deposition (CVD) process. The encapsulation of gold nanoparticles enabled surface enhanced Raman spectroscopy (SERS) detection of glycine inside the cavity of the nanotubes. Iron oxide particles are partially reduced to metallic iron during the CVD process giving the nanotubes ferromagnetic behaviour. At high nanoparticle concentrations, particle agglomerates can form. These agglomerates or larger particles, which are only partially embedded in the walls of the nanotubes, are covered by additional carbon layers inside the hollow cavity of the tube producing hillocks inside the nanotubes, with sizes comparable to the bore of the tube.
Estimation of Velocity Vectors in Synthetic Aperture Ultrasound Imaging (2006)

A method for determining both velocity magnitude and angle in a synthetic aperture ultrasound system is described. The approach uses directional beamforming along the flow direction and cross correlation to determine velocity magnitude. The angle of the flow is determined from the maximum normalized correlation calculated as a function of angle. This assumes the flow direction is within the imaging plane. Simulations of the angle estimation method show both biases and standard deviations of the flow angle estimates below 3 degrees for flow angles from 20 degrees to 90 degrees (transverse flow). The method is also investigated using data measured by an experimental ultrasound scanner from a flow rig. A commercial 128 element 7-MHz linear array transducer is used, and data are measured for flow angles of 60 degrees and 90 degrees . Data are acquired using the RASMUS experimental ultrasound scanner, which samples 64 channels simultaneously. A 20-micros chirp was used during emission and eight virtual transmit sources were created behind the transducer using 11 transmitting elements. Data from the eight transmissions are beamformed and coherently summed to create high-resolution lines at different angles for a set of points within the region of flow. The velocity magnitude is determined with a precision of 0.36% (60 degrees) and 1.2% (90 degrees), respectively. The 60 degrees angle is estimated with a bias of 0.54 degrees and a standard deviation of 2.1 degrees. For 90 degrees the bias is 0.0003 degrees and standard deviation 1.32 degrees. A parameter study with regard to correlation length and number of emissions is performed to reveal the accuracy of the method. Real time data covering 2.2 s of the carotid artery of a healthy 30-year-old male volunteer is acquired and then processed offline using a computer cluster. The direction of flow is estimated using the above mentioned method. It is compared to the flow angle of 106 degrees with respect to the axial direction, determined visually from the B-mode image. For a point in the center of the common carotid artery, 76% of the flow angle estimates over the 2.2 s were within 10 degrees of the visually determined flow angle. The standard deviation of these estimates was below 2.7 degrees. Full color flow maps from different parts of the cardiac cycle are presented, including vector arrows indicating both estimated flow direction and velocity magnitude.
High-contrast imaging of plastic-embedded tissues by phase contrast electron microscopy (2009)

Phase contrast electron microscopy utilizing phase plates has been considered suitable for high-contrast observation of weak phase objects. This novel technique was newly applied to histochemically stained strong phase objects of osmificated biological specimens. Sections of various thicknesses, specifically stained for the Golgi apparatus by the ZIO technique using the heavy metals Zn and Os, were observed with a phase contrast electron microscope in Zernike and Hilbert imaging modes. Quantitative analysis of image contrast in real space and the power spectrum in Fourier space showed a high-contrast gain even for strong phase objects. This result clearly indicates that phase contrast electron microscopy can be effectively used not only for weak phase objects but also for strong phase objects in biology.
Robust cooperative networking and interference management in next-generation wireless networks (2011)

Cooperative wireless communication techniques provide the spatial diversity gain over wireless channels by recruiting relay stations that overhear other transmissions to jointly forward information to the intended destination, thereby yielding higher reliability and throughput than direct transmission. While conventional single-relay and distributed spacetime coding (DSTC) based multi-relay cooperative schemes have been employed in various wireless networks, they suffer from performance degradation in a mobile environment due to their inability to track relays. A novel DSTC, called randomized distributed space-time coding (R-DSTC), is able to solve the problems introduced by mobility and is superior to the direct transmission scheme as well as other cooperative schemes. As a fully decentralized cooperative scheme, R-DSTC requires simpler relay selection and much less channel information to operate than all cooperative schemes. 
While R-DSTC is well studied in the physical (PHY) layer, in order to realize its performance benefits in upper layers, we developed medium access control (MAC) protocols for the IEEE 802.11WiFi and IEEE 802.16WiMAX networks, called STiCMAC and CoopMAX, respectively. We design a cooperative PHY/MAC cross-layer framework that fully exploits the opportunistic diversity gain of multiple relays. New signaling messages are provided in support of the protocol operation. We developed efficient rate adaptation algorithms that optimize the transmission parameters, such as data rates and space-time code dimension, for these new protocols. Our proposed protocols minimize the signaling cost and maximize the end-to-end throughput for each source/destination pair while maintaining an acceptable end-to-end packet error probability. The system performance of STiCMAC and CoopMAX is evaluated in both a stationary and mobile scenario. These new R-DSTC based protocols are shown to greatly outperform all other direct and cooperative schemes in terms of throughput, delay and interference reduction. In particular, our R-DSTC based cooperative protocols provide robust relaying and undergo the minimal performance loss in a mobile environment. 
In this work, we also study the inter-cell interference management problem in the uplink of a multi-cell orthogonal frequency division multiple access (OFDMA) based wireless cellular network. A fully distributed frequency planning scheme is developed to improve the performance of the edge users at the boundary of a cell. Our scheme splits each cell into seven sectors and minimizes the inter-cell interference to the edge sectors of each cell. The user performance is measured in terms of signal-to-interference-plus-noise ratio (SINR). We compared our scheme with standard interference control schemes, i.e., Fractional Frequency Reuse (FFR), employed in current OFDMA based cellular systems, i.e. WiMAX and LTE, showing that a higher SINR gain can be achieved by our new scheme for the edge users under full frequency reuse.
GREEN: an active queue management algorithm for a self managed Internet (2003)

In this paper we introduce a new active queue management (AQM) algorithm called GREEN. GREEN provides high link utilization whilst maintaining low delay and packet loss. GREEN enables low latency interactive applications such as telephony and network games. GREEN is shown to outperform the current AQM algorithms. Certain performance problems with current AQMs are discussed.
Dental Dynamic Diagnostics Using Simultaneous Frequency-domain PTR and Laser Luminescence (2002)

Frequency-domain infrared photothermal radiometry is introduced as a dynamic dental diagnostic tool complimentary to laser luminescence for quantifying sound and defective enamel or dentin. A high-spatial-resolution dynamic experimental imaging set-up, which can provide simultaneous measurements of laser-induced frequency-domain infrared photothermal radiometric and luminescence signals from defects in teeth, has been developed.. 1 Following optical absorption of laser photons, the new set-up can monitor simultaneously and independently the non-radiative (optical-to-thermal) conversion via infrared photothermal radiometry; and the radiative de-excitation via luminescence emission. In addition, the optical properties of enamel are determined using a three-dimensional luminescence and photothermal model.
Double phase-conjugate fiber-optic gyro (1986)

We describe and demonstrate a new type of phase-conjugate fiber-optic gyro 1 (PCFOG). PCFOGs use phase conjugation to compensate for reciprocal phase changes due to thermal and mechanical effects on the fiber, while at the same time allowing for the measurement of the nonreciprocal phase shift produced by rotation. Where the best standard fiber-optic gyros require polarization-preserving fibers and couplers to avoid polarization scrambling that is a source of noise and signal fading, PCFOGs can avoid this problem by using polarization-preserving phase conjugation. 2 This has the advantage of allowing for the use of inexpensive nonpolarization preserving and even multimode fibers and components. The double PCFOG is simply an interferometer, in which both arms contain fiber-optic coils terminated by the same self-pumped phase-conjugate mirror. We have recently demonstrated rotation sensing using such an interferometer with a self-pumped crystal of barium titanate as the phase-conjugate mirror. For this demonstration, the entire interferometer was mounted on a rotary table and light was piped to the table using a fiber optic. In addition to the simplicity of the new self-pumped version of the PCFOG, it has the advantage of allowing for the use of fiber-optic coils that are longer than the coherence length of the laser to increase the sensitivity of the gyro.
RETRACTED: Nanoparticle-Assisted Ultrasound for Cancer Therapy (2017)

Short Retraction Notice The authors want to retract the paper for his own reason. This article has been retracted to straighten the academic record. In making this decision the Editorial Board follows COPE's Retraction Guidelines. Aim is to promote the circulation of scientific research by offering an ideal research publication platform with due consideration of internationally accepted standards on publication ethics. The Editorial Board would like to extend its sincere apologies for any inconvenience this retraction may have caused. Editor guiding this retraction: Prof. Hao Lin (EiC of JBiSE) The full retraction notice in PDF is preceding the original paper which is marked "RETRACTED".
APPLICABILITY OF AN AGROBACTERIUM-BASED SYSTEM FOR THE TRANSFORMATION OF MUSA SPECIES WITH DIVERSE GENOMIC CONSTITUTION AND PLOIDY LEVEL (2000)

ISHS I International Symposium on Banana: I International Conference on Banana and Plantain for Africa APPLICABILITY OF AN AGROBACTERIUM-BASED SYSTEM FOR THE TRANSFORMATION OF MUSA SPECIES WITH DIVERSE GENOMIC CONSTITUTION AND PLOIDY LEVEL
A 160 mV, fully differential, robust schmitt trigger based sub-threshold SRAM (2007)

We propose a novel Schmitt Trigger (ST) based fully differential 10 transistor SRAM (Static Random Access Memory) bitcell suitable for sub-threshold operation. The proposed Schmitt trigger based bitcell achieves 1.56X higher read static noise margin (SNM) (VDD = 400mV) compared to the conventional 6T cell. The robust Schmitt trigger based memory cell exhibits built in process variation tolerance that gives tight SNM distribution across the process corners. It utilizes fully differential operation and hence does not require any architectural changes from the present 6T architecture. At iso-area and iso-read-failure probability the proposed memory bitcell operates at a lower (175mV) VDD with 18% reduction in leakage and 50% reduction in read/write power compared to the conventional 6T cell. Simulation results show that the proposed memory bitcell retains data at a supply voltage of 150mV. Functional SRAM with the proposed memory bitcell is demonstrated at 160mV in 0.13μm CMOS technology.
Emergency Release for Winter Sports Equipment (2010)

Abstract Using a pyrotechnical pill, Winter sports equipment can be electrically released and removed, where mechanical opening is impossible because of missing torque between binding and equipment, e.g., at avalanche and tree-well situations or at ski base jumping with a wingsuit. Since the pill driven binding opening is very fast (∼1 ms), it may also be advantageous at a ski downhill racer accident.
Luminescence from defects and impurity centers in yttrium oxide (1989)

High-purity (99.999%) Y{sub 2}O{sub 3} powder is used as a starting material for fabricating high-temperature superconductors (HTS), and is frequently found as an unreacted second phase in the final product. We have found that as-received Y{sub 2}O{sub 3} contains Tb{sup 3+} paramagnetic impurity ions as determined by TSL and emission-spectra measurements. Deep luminescence traps (presumably Tb{sup 4+} ions) are formed in Y{sub 2}O{sub 3} when it is exposed to {gamma}-rays, x rays, or fluorescent lights. These deep traps can only be removed by annealing the material to near 1600{degree}C. Given the short coherence length of HTS it is possible that order-of-magnitude variations in the Tb impurity concentration of starting materials may affect the ultimate value of surface resistance (R{sub s}).