gebhart/patrepeval huggingface dataset:
A novel quasi-optical monopulse-tracking system for millimeter-wave application (1996)

A novel, low-loss, polarization-independent quasi-optical monopulse comparator (QOMC) has been developed as an alternative to the commonly used waveguide comparator. It has been implemented as an experimental model with an aperture of 23/spl times/23 wavelengths for a 140-GHz monopulse tracking antenna fed by a beam waveguide. The QOMC consists of two cascaded identical stages (sections) to perform azimuth and elevation angle measurements. Each comparator stage is composed of only two plane-parallel reflectors and a low-loss quasi-optical 3-dB beam splitter symmetrically positioned in between them. Extensive model calculations of a single QOMC stage with square aperture dimensions between 10 and 25 wavelengths, and experimental investigations of the realized two-stage QOMC in a beam-waveguide field were performed. Owing to its sufficient high dynamic range at bandwidths of up to about 300 MHz, and particularly, its low absorptive loss of less than 3.5% per stage at 140 GHz, this QOMC is suited ideally for millimeter-wave applications.
Noise propagation in SPECT images reconstructed using an iterative maximum-likelihood algorithm (1993)

The effects of photon noise in the emission projection data and uncertainty in the attenuation map on the image noise in attenuation-corrected SPECT images reconstructed using a maximum-likelihood expectation-maximization algorithm were investigated. Emission projection data of a physical Hoffman brain phantom and a thorax-like phantom were acquired from a prototype emission-transmission computed tomography (ETCT) scanner being developed at UCSF. Computer-simulated emission projection data from a head-like phantom and a thorax-like phantom were also obtained using a fan-beam geometry consistent with the ETCT system. The simulation assumed a 99Tcm source, included collimator blurring but ignored photon scatter. For each phantom, a region of interest (ROI) at the centre of the reconstructed image was chosen for the purpose of noise analysis. In all cases, the mean value (m) in the ROI approached a constant value after approximately 20 iterations. The standard deviation (sigma) generally increased with the number of iterations. The ratio (sigma/m) was found to be inversely proportional to the square root of the total detected counts and proportional to the relative uncertainty in the attenuation maps. These two noise components contributed independently towards the noise in the reconstructed image. In the ETCT system employing an x-ray tube for attenuation map acquisition, the uncertainty in the reconstructed radionuclide distribution is limited mainly by photon noise in the emission projection data. Our results are expected to be generally applicable to other emission-transmission systems, including those using external radionuclide sources for the acquisition of attenuation maps.
The Buckling of Thin Spherical Shells (1961)

Precise numerical solutions are obtained for the energy and equilibrium equations given by Th. von Karman and H. S. Tsien for thin spherical shells under uniform external pressure. The method of solution employs a power series expansion to move away from the singularity at the initial boundary, and a stepby-step integration procedure throughout the desired open­ ing of the shell. The small angle assumption is eliminated without introducing trigonometric computation. For fixed ra­ dius and thickness, the various equilibrium configurations of the shell are obtained as a function of two parameters, one corre­ sponding to external pressure and the other corresponding to the curvature of the shell at the central point. The solutions indicate clearly the behavior of the shell in both the pre-buckled and post-buckled states, and yield distinct values for the upper and lower buckling loads. These critical loads are determined on the basis of the load-deflection char­ acteristics. The results obtained depend critically on terms which are neglected in the classical theory by the process of linearization. The same computing procedures were applied to the mathe­ matical formulation of Keller, Greenberg, and Reiss and yield an improved resolution of the phenomena associated with buckling. The calculations were performed on the IBM 650 Electronic Data Processing Machine.
Cinnolines. II : On the Reaction of 4-(Methylsulfonyl)-cinnoline with Nucleophiles (1968)

4-(Methylsufonyl)cinnoline (I) gradually undergoes decomposition when left in air and changes into 4-cinnolinol (IV). I easily undergoes decomposition into IV when heated with water and the decomposition is further facilitated when heated with a dilute acid. When I is heated in aqueous solution of sodium hydroxide or in methanolic solution of sodium methoxide, IV or 4-methoxycinnoline (V) is formed. Application of aniline, hydrazine, or hydroxylamine to I respectively gives 4-anilino-(VI), 4-hydrazino-(VII), or 4-hydroxyamino-cinnoline (VIII) (Chart 2). The methylsulfonyl group in I is substituted also with active methylene (methine) carbanion. For example, reaction of I, in the presence of sodium amide, with ethyl acetoacetate (IXa), ethyl malonate (IXb), ethyl cyanoacetate(IXc), malononitrile(IXd), phenylacetonitrile(IXe), or ethynylbenzene (IXf) respectively affords ethyl 4-cinnolineacetate (Xa'), ethyl 4-cinnolinemalonate (Xb), ethyl α-cyano-4-cinnolineacetate (Xc), 4-cinnolinemalononitrile (Xd), α-phenyl-4-cinnolineacetonitrile (Xe), or 4-(phenylethynyl)cinnoline (Xf) (Chart 3 and Table I).
Vacuum-Ultraviolet Absorption Spectrum of Polyethylene (1966)

The absorption spectrum of polyethylene is reported from onset of absorption, at about 1780, to 1050 Å. The spectrum and probably also the solid-phase ionization potential, is shown to be similar to those of short chain n-alkanes in the vapor phase. No evidence is found of ``dissociative excitons'' or of an intramolecular band structure in polyethylene, while the probable ionization potential seems higher than suggested by some theoretical calculations.
Synthetic Nucleosides and Nucleotides. VIII. Direct Synthesis of the 5'-Phosphate of 4-Thiouridine, 6-Thioinosine and 6-Thioguanosine from the Corresponding Oxy Nucleotide via Thiation Procedure (1971)

Direct and simple methods for the preparations of 4-thiouridine 5'-phosphate (IVa), 6-thioinosine 5'-phosphate (IVb) and 6-thioguanosine 5'-phosphate (IVc) from the corresponding oxy-nucleotides are described. The 5'-ribonucleotides are converted to their 2', 3'-di-O-acetylated derivatives by a conventional acetylation procedure, followed by thiation with phosphorus pentasulfide to give crude thiated products. For the selective desulfurization, the crude products are treated with dicyclohexylcarbodiimide, followed by alkaline deacylation to give the desired "thio" nucleotides.
Temperature distribution in semiconductor wafers heated in a vertical diffusion furnace (2003)

The transient temperature distribution in a row of wafers heating in a vertical diffusion furnace was calculated as the heating power of the furnace was PID (proportional plus integral plus derivative) controlled. Radiative heat transfer was combined with axisymmetric unsteady conduction in wafers and the furnace. With feedforward control of the heating power (which means that when wafers are inserted into the furnace, the heater temperature is set higher than the desired heating temperature), the temperature of the wafers reached the heating temperature rapidly. The radiative properties of silicon wafers changed from semitransparent to opaque at 500 degrees C, and the effect of this change on the temperature distribution in the wafers was calculated. Thermoplastic deformation of the wafers is more likely to occur during withdrawal than during insertion.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>
Wireless bidirectional relaying and Latin Squares (2012)

The design of modulation schemes for the physical layer network-coded two way relaying scenario is considered with the protocol which employs two phases: Multiple access (MA) Phase and Broadcast (BC) Phase. It was observed by Koike-Akino et al. that adaptively changing the network coding map used at the relay according to the channel conditions greatly reduces the impact of multiple access interference which occurs at the relay during the MA Phase and all these network coding maps should satisfy a requirement called the exclusive law. We show that every network coding map that satisfies the exclusive law is representable by a Latin Square and conversely, and this relationship can be used to get the network coding maps satisfying the exclusive law. Using the structural properties of the Latin Squares for a given set of parameters, the problem of finding all the required maps is reduced to finding a small set of maps for M-PSK constellations. This is achieved using the notions of isotopic and transposed Latin Squares. Furthermore, the channel conditions for which the bit-wise XOR will perform well is analytically obtained which holds for all values of M (for M any power of 2). We illustrate these results for the case where both the end users use QPSK constellation.
Effect of Continuous Glucose Monitoring on Glycemic Control in Patients With Type 2 Diabetes Treated With Basal Insulin (2021)

ClinicalTrials.gov Identifier: NCT03566693.
Human thymus retrovirus. Is human thymus retrovirus a pathogenic virus for human autoimmune diseases? (1985)

The involvement of retroviruses has been shown in the pathogenesis of autoimmunity in animal models of autoimmune diseases. Changes in the thymus gland are frequently found in a variety of human autoimmune diseases. Abnormal B cell proliferation are observed in such autoimmune thymuses. We cultured thymus cells of autoimmune patients with B cells and observed the appearance of retrovirus particles in the cultured thymus cells. Antibodies to the retrovirus-related antigens were detected in sera of patients with autoimmune diseases. The findings suggest the possibility that activated retroviruses in thymus cells of autoimmune patients may be involved in the pathogenesis of human autoimmune diseases.
Die Entdeckung einiger biologischer Wirkungen von Stickstoffmonoxid und seiner Rolle für die Zellkommunikation (Nobel-Vortrag) (1999)

Ein einzigartig einfaches Molekül mit einer Vielzahl von Signalfunktionen: NO. Das freie Radikal Stickstoffmonoxid vermittelt nicht nur viele biologische Wirkungen, indem es die Guanylat-Cyclase aktiviert und so die Synthese von cyclischem GMP aus GTP verstärkt, sondern es kann auch mit Übergangsmetallen wie Eisen, mit Thiolgruppen, anderen freien Radikalen, Sauerstoff, dem Superoxid-Anion, ungesättigten Fettsäuren und anderen Molekülen reagieren. Außer als intrazellulärer Botenstoff kann NO auch als Autocoid, parakrine Substanz oder Neurotransmitter fungieren oder als ein Hormon, das an entfernte Wirkorte transportiert werden kann, um dort seine Funktion auszuüben.
A PERSPECTIVE ON MEXICAN ETHNOBOTANY (1990)

The following commentary represents a personal view of some aspects of ethnobotanical research in Mexico that may help to better understand its present orientation.In addition, C. Earle Smith Jr.'s contribution to Mexican ethnobotany is considered.The current focus of Mexican ethnobotanical research is seen as the result of increasing politization and developing social consciousness among investigators, and is largely directed towards applied research which seeks to directly benefit needy sectors of society as well as the scientific community.
Low-noise operation of a diode-pumped intracavity-doubled Nd:YAG laser using a Brewster plate (1992)

The authors demonstrate noise reduction which has been attained in a diode-pumped intracavity-doubled Nd:YAG laser by using a novel birefringent filter formed by a Brewster plate and a birefringent KTP crystal. It is confirmed that single longitudinal mode operation is obtained by the birefringent filter. As a result, the relative intensity noise obtained is less than -135 dB Hz. This noise reduction technique should play an important role for application of laser-diode pumped intracavity-doubled solid-state lasers.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>
On the Efficient Design of Neural Networks in Communication Systems (2019)

Various types of neural networks (NNs) have shown promising performance in communication systems. However, the low-latency implementation of these tasks is currently impractical due to the high computational complexity and large model size of NNs. In this paper, we propose an iterative optimization framework with retraining process to adaptively find the quantization scheme for different NNs. Moreover, the efficient design of convolutional neural networks is presented to reduce the required parameters and computational complexity. Experiment results for modulation classification, channel decoder and equalizer are presented. Compared to the original full-precision models, the quantized NN models achieve comparable performance with only 4 to 5 weight bits and 8-bit activation. The size of optimized models is significantly compressed and the hardware complexity of the NN inference is also reduced.
Cyberbullying and Cyberthreats: Responding to the Challenge of Online Social Aggression, Threats, and Distress (2006)

Online communications can be cruel and vicious. They take place 24/7. Damaging text and images can be widely disseminated and impossible to fully remove. There are emerging reports of youth suicide, violence, and abduction related to cyberbullying and cyberthreats. In this book,the author provides school counselors, administrators, teachers and parents with cutting-edge information on how to prevent and respond to cyberbullying and cyberthreats. It covers challenging issues that occur as students embrace the Internet and other digital technologies such as: *Sending offensive, harassing messages *dissing someone or spreading nasty rumors online *Disclosing someone's intimate personal information *Breaking into someone's e-mail account and sending damaging messages under that person's name *Excluding someone from an online group *Using the Internet to intimidate The book includes detailed guidelines for managing in-school use of the Internet and personal devices, including cell phones. Appendices contain reproducible assessment and program forms, as well as parent and student handouts.
Attacks and improvements to chaotic map‐based RFID authentication protocol (2015)

Abstract Because of its low cost and ease of deployment, radio frequency identification (RFID) technology offers great potential for all applications that require identification. Main obstacle for wide adoption of this technology is the concerns about its security and privacy issues. Many RFID authentication protocols have been proposed to provide desired security and privacy level for RFID systems. Recently, Benssalah et al . have proposed a chaotic map‐based RFID security protocol. In this paper, we analyze the security of this protocol and discover its vulnerabilities. We show that message generation arises some weaknesses, and this protocol is vulnerable to tracking, tag impersonation, and de‐synchronization attacks. The success probabilities of the proposed attacks are significant, and their complexities are polynomial. Furthermore, we propose an RFID authentication protocol. Our protocol utilizes the Chebyshev chaotic map hard problem and conforms to the EPCglobal Class 1 Generation 2 (EPC C1‐G2) standard. Our protocol eliminates the weaknesses of the protocol of Benssalah et al . Copyright © 2015 John Wiley & Sons, Ltd.
Multilevel evaluation of electromagnetic fields for the rapid solution of scattering problems (1994)

Abstract A multilevel algorithm is presented for evaluating fields generated by given distributions of electric current. The algorithm can be used to accelerate the solution of scattering problems using the method of moments and/or boundary element methods. The algorithm exploits the limited number of degrees of freedom that characterize a field observed over a domain that is well separated from a source domain. Both the memory requirements and the computational complexity of the algorithm are O(N s log(N s )), where N s is the common number of sources and observation points. The multilevel algorithm can easily be incorporated into existing method‐of‐moments (MoM) programs. A simple physical interpretation of the algorithm is provided. © 1994 John Wiley & Sons, Inc.
Derivatization of Optically Transparent Materials with Diazonium Reagents for Spectroscopy of Buried Interfaces (2009)

This paper presents a method to derivatize a wide variety of substrate materials that are frequently used in spectroscopic characterizations with molecular layers through the reduction of aromatic diazonium reagents. The method relies on an ultrathin (5 nm) layer of a reactive metal (e.g., Ti or Al) deposited as a primer that subsequently mediates the reduction of aromatic diazonium reagents from acetonitrile solution. Following surface modification, the Ti can be oxidized to provide a passivated support surface. Raman, Infrared, UV-vis and X-ray photoelectron spectroscopic techniques are used to characterize the molecular layers on the metal primer surface. When a Ti primer layer is derivatized via diazonium reduction, the molecule is shown to be present on the ultrathin Ti layer on Au, Al, quartz, Si/SiO(x), glass, and polyethylene surfaces. For molecules bound to a Ti primer, the molecular layer was found to be stable to sonication in acetone or acetonitrile, a 1 h exposure to boiling water, and a 30 min exposure to 0.1 M acid or base. The approach also permits spectroscopic characterization of buried thin-film molecular layers on optically transparent substrates after deposition of thick top metal contacts.
Low temperature plasma deposition of silicon nitride from silane and nitrogen plasmas (1998)

The plasma enhanced chemical vapor deposition of silicon nitride films from SiH4 and N2 gases was investigated below 450 K in a helical resonator plasma reactor using in situ spectroscopic ellipsometry and in situ attenuated total reflection Fourier transform infrared spectroscopy. Silicon nitride growth proceeds through nitridation of a thin Si-rich region at the film surface and the effects of the externally controlled parameters, such as plasma power and pressure, on the film composition and structure can be understood in terms of this mechanism. The key factor that affects the film composition and structure is the active nitrogen (N2*) flux arriving at the surface which determines the nitridation rate of Si–Si bonds. Silicon nitride films deposited using low plasma power and high pressure, conditions that produce low N2* flux, contains a relatively high concentration of H in the form of Si–H and a-Si inclusions. Increasing the power or decreasing the pressure results in higher N2* flux and nitridation rate. The films deposited under such conditions have less SiH and a-Si incorporation but higher NHx (x=1,2) which disrupts the interconnectedness of the nitride network resulting in films that contain voids. Film properties can be tailored and optimized between these two extremes by manipulating power and pressure.
Challenges and interesting observations associated with feedback-controlled nanoindentation (2004)

Accurate feedback control of the nanoindentation process is particularly challenging from the perspectives of many orders of magnitude change in contact stiffness and the use of the ramp/hold/ramp protocol. The conventional proportional-integral-derivative feedback control algorithm is not well suited for such an application. Here we provide a description and present performance data for a newly developed digital control algorithm that augments the familiar proportional-integral-derivative routine with an adaptive feedforward control having inputs related to open-loop device physics and encountered contact mechanics. This novel approach results in reproducing even a steep demand ramp with minimal feedback error. Additionally, we discuss interesting observations made with respect to the varied displacement-controlled nanoindentation responses of materials. Metals, in particular, are found to expose especially rich nanomechanical phenomena when the force-displacement curves are measured under displacement control. The findings of this study nicely illustrate the decided scientific advantages of displacement control over load control.
Electrochemistry, Stability, and Alkene Complexation Chemistry of Copper(I) Triflate in Aqueous Solution. Potential for Use in Electrochemically Modulated Complexation-Based Separation Processes (1997)

Copper(I) trifluoromethanesulfonate (CuOTf), which is insoluble in water, reacted with vinyl sulfonate anion (VS) to form a water soluble complex (concentrations > 0.1 M). Acidic CuOTf solutions prepared with relatively large VS/Cu(I) ratios were comparable in stability to solutions containing excess chloride ion. Reversible binding of alkenes (ethylene, 1,3-butadiene and 1-butene) to copper(I) in aqueous CuOTf/VS solutions was observed by 1H-NMR. The copper(I) displayed a competitive reaction with VS and the alkenes. This allowed the binding affinity of the alkenes to the copper(I) to be calculated based on the proton chemical shift for VS. The strength of alkene complexation followed the order ethylene > 1-butene ≈ 1,3-butadiene. The electrochemistry for the Cu(II/I) couple showed a quasi-reversible reaction that depended on acidity and the concentration of VS in the solution. Binding to copper(I) caused substantial amounts of the alkenes to be absorbed into CuOTf/VS solutions from the gas phase, especially at low [VS]/[Cu(I)] ratios. Calculations indicated that CuOTf in aqueous solution containing VS is superior to CuCl in chloride media for electrochemically modulated complexation-based separation of alkenes from alkanes.
Surface emitting quantum well lasers (1990)

Vertical cavity surface emitting lasers1-5 are generating much interest due to their geometric suitability for forming 2-D arrays and their potential for achieving ultralow thresholds. Here we report on electrically driven vertical cavity microlasers (μlasers) which have transverse dimensions of a few microns and active material lengths of a few hundred angstroms. The very small volumes are a key factor in achieving low thresholds.
14 GHz bandwidth MSM photodiode AlGaAs/GaAs HEMT monolithic integrated optoelectronic receiver (1993)

A monolithic optoelectronic receiver consisting of an MSM photodiode and a two-stage amplifier has been fabricated using an enhancement/depletion 0.3 μm recessed-gate AIGaAs/GaAs HEMT process. The bandwidth of 14.3 GHz implies suitability for transmission rates of up to 20 Gbit/s. The transimpedance is 670 Ω (into 50 Ω) and the projected sensitivity is −16.4 dBm (BER = 10−9).
Robust frequency shaping sliding mode control (2000)

Frequency shaping, linked with linear quadratic optimal and sliding mode control, is a technique for controlling systems with uncertainties. The authors propose some new methods for designing the sliding surface and sliding mode control when the LQ weighting functions are not constant at all frequencies. Furthermore, they introduce conditions for which the spectrum of the original reduced system is a subset of the spectrum of the augmented system, and develop an iterative optimal construction procedure for the sliding mode.