gebhart/patrepeval huggingface dataset:
Monolithic single-shot dispersion-scan: A new tool for real-time measurement and optimization of femtosecond pulses (2017)

Summary form only given. The precise characterization of femtosecond laser pulses is as challenging as their generation and a topic of intense research. Dispersion-scan (d-scan) [1] is a recently established technique where the spectrum of a nonlinear signal, e.g., second-harmonic generation (SHG), is measured as a function of dispersion applied to the pulse. The spectral phase of the pulse can then be retrieved from the resulting 2D trace using an iterative algorithm. An important implementation of d-scan, based on a chirped mirror and wedge compressor, involves progressively moving one of the wedges around the maximum compression point and acquiring the resulting SHG spectrum for each insertion with a standard spectrometer. This robust and fully inline approach, which does not require any beamsplitting or temporal delays, has enabled the simultaneous compression and measurement of pulses down to single-cycle durations [2-4], but its scanning nature precludes single-shot operation. A single-shot d-scan variant that explores the spatially dependent dispersion of a glass prism was successfully demonstrated with 3.2 fs pulses [5], but the relatively small amount of dispersion that can be introduced by a single prism limits its use to few-cycle pulses.Here we present a novel single-shot d-scan architecture, based on automatically phase-matched transverse SHG (TSHG) [6] in a random nonlinear crystal. The crystal itself serves as a highly dispersive and ultra-broadband nonlinear medium simultaneously, enabling the live single-shot measurement of a two-dimensional SHG d-scan trace with an imaging spectrometer placed perpendicularly to the propagation direction. The setup is fully inline and extremely compact, without any moving parts. Owing to the large transparency range of the crystal and the ultra-broadband phase-matching characteristics of TSHG, one is in principle able to measure pulses with Fourierlimited durations down to 4 fs and longer than 100 fs, with spectra from 400 to 2200 nm, as long as the central wavelength is higher than 750 nm. Figure 1 shows a measurement example of pulses from a sub-30-fs 1 kHz Ti:Sapphire CPA laser system equipped with an acousto-optic programmable dispersive filter (AOPDF). Imparting a given amount of third-order dispersion (TOD) on the pulse results in a clearly tilted d-scan trace, as expected [1]. For example, by feeding back the d-scan measured phase into the AOPDF, Fourier-limited pulses trace are obtained. We should point out that the repetition rate of the measurement is only limited by the speed of the 2D detector and available laser energy, and is in principle scalable to higher repetition rates. In summary, this new monolithic single-shot d-scan architecture based on TSHG in a nonlinear random crystal provides a compact but scalable tool for convenient and intuitive real-time visualization, measurement and control of ultrashort light pulses over a broad wavelength range.
Polymer containing pendant vinyl ether groups useful in enhanced oil recovery using (1990)

This patent describes an improvement in a method for recovering oil from an underground oil-bearing earth formation penetrated by an injection well and a producing well, in which method carbon dioxide is injected into the formation to displace oil towards the producing well from which oil is produced to the surface. It comprises: injecting into the formation carbon dioxide, the viscosity of which is increased at least three-fold by the presence of a sufficient amount of polymer containing pendant vinyl ether groups and a sufficient amount of a cosolvent to form a solution of the polymer in the carbon dioxide, wherein the minimum solubility parameter of the polymer is reduced to 6.85(cal/cc)1/1/2 or less by control of the number of pendant vinyl ether groups and by the selection of the vinyl ether groups.
Formation of Single-Wall Carbon Nanotubes:  Comparison of CO<sub>2</sub> Laser Ablation and Nd:YAG Laser Ablation (1999)

Investigating the formation of single-wall carbon nanotubes (SWNTs) from a target composed of graphite, Ni, and Co, we compared the use of a pulsed CO2 laser (pulse width of 20 ms, laser-power density of 0.1 MW/cm2) with the use of a pulsed Nd:YAG laser (pulse width of 5−7 ns, laser-power density of 4 GW/cm2). When the total irradiation energy was 2 kW/cm2 for the CO2 laser ablation and 2.4 kW/cm2 for the Nd:YAG laser ablation, SWNTs could be formed at 300 K by CO2 laser ablation, whereas the lowest temperature at which they could be formed by Nd:YAG laser ablation was about 1170 K. The lowest pressure allowing SWNT formation was 50 Torr for CO2 laser ablation and 200 Torr for Nd:YAG laser ablation. The structures of carbonaceous deposits and of the target surfaces indicated that CO2 laser ablation resulted in carbon being emitted from the edges of or defects in the graphite particles and most of the Ni and Co being emitted from the target. Pulsed Nd:YAG laser ablation, on the other hand, has been reported to result in graphite melting and mixing with Ni and Co on the target surface, the mixture being expelled from the target surface, and clumps of Ni and Co remaining on the target surface after the laser ablation. We think these differences are due to the different laser-power densities and pulse widths.
A test system for automated characterization of performance relevant storage media defects (2002)

Defects in magnetic hard disk media reduce the performance of hard disk drives. A consequence of the increasing storage density is that submicrometer defects in the magnetic storage media become more relevant. However, finding and visual inspection of these defects under an optical microscope is problematic. Therefore, a spin test stand technique was used to reliably map the performance of relevant storage media defect positions, and a computer controlled technique was developed which positions those defects relative to a local analysis tool within 45 s. The accuracy and repeatability was measured to be /spl plusmn/0.05/spl deg/ in angular (approximately /spl plusmn/30 /spl mu/m of a circular arc) and /spl plusmn/5 /spl mu/m in radial direction, respectively. Here, surface analysis of defects has been performed using scanning force microscopy. Defect and disk features with heights < 1 nm have been measured routinely while defect diameters were in the range of 1 /spl mu/m to 250 nm. In particular, nontopographic defects are visualized by means of magnetic force microscopy.
Identification and characterization of the lantibiotic nisin Z, a natural nisin variant (1991)

Lactococcus lactis strain NIZO 22186 produces an extracellular, lanthionine-containing 3.5-kDa polypeptide with antimicrobial activity. Its retention time on reversed-phase (RP) HPLC and its amino acid composition showed high similarities but no complete identity to nisin. The gene for this lantibiotic, designated nisZ, has been cloned and its nucleotide sequence was found to be identical to that of the precursor nisin gene apart from a single mutation resulting in the substitution His27Asn in the mature polypeptide. NMR studies of the natural nisin variant, which has been designated nisin Z, confirmed the His27Asn substitution and indicated that it has a similar structure to nisin.
Mode Spectrum and Temporal Soliton Formation in Optical Microresonators (2014)

The formation of temporal dissipative solitons in optical microresonators enables compact, high-repetition rate sources of ultrashort pulses as well as low noise, broadband optical frequency combs with smooth spectral envelopes. Here we study the influence of the microresonator mode spectrum on temporal soliton formation in a crystalline MgF2 microresonator. While an overall anomalous group velocity dispersion is required, it is found that higher order dispersion can be tolerated as long as it does not dominate the resonator's mode structure. Avoided mode crossings induced by linear mode coupling in the resonator mode spectrum are found to prevent soliton formation when affecting resonator modes close to the pump laser frequency. The experimental observations are in excellent agreement with numerical simulations based on the nonlinear coupled mode equations. The presented results provide for the first time design criteria for the generation of temporal solitons in optical microresonators.
Regeneration of metallic catalysts (1980)

Several midbrain nuclei degenerate in Parkinson's Disease (PD). Many of these nuclei share the common characteristics that are thought to contribute to their selective vulnerability, including pacemaking activity and high levels of calcium influx. In addition to the well-characterized dopaminergic neurons of the substantia nigra pars compacta (SNc), the cholinergic neurons of the pedunculopontine nucleus (PPN) also degenerate in PD. It is well established that the low-threshold L-type calcium current is a main contributor to tonic calcium in SNc dopaminergic neurons and is hypothesized to contribute to their selective vulnerability. However, it is not yet clear whether the vulnerable PPN cholinergic neurons share this property. Therefore, we used two-photon dendritic calcium imaging and whole-cell electrophysiology to evaluate the role of L-type calcium channels in the tonic and phasic activity of PPN neurons and the corresponding dendritic calcium signal and directly compare these characteristics to SNc neurons. We found that blocking L-type channels reduces tonic firing rate and dendritic calcium levels in SNc neurons. By contrast, the calcium load in PPN neurons during pacemaking did not depend on L-type channels. However, we find that blocking L-type channels reduces phasic calcium influx in PPN dendrites. Together, these findings show that L-type calcium channels play different roles in the activity of SNc and PPN neurons, and suggest that low-threshold L-type channels are not responsible for tonic calcium levels in PPN cholinergic neurons and are therefore not likely to be a source of selective vulnerability in these cells.
Detection of Toxic Chemicals for Homeland Security Using Polyaniline Nanofibers (2007)

The electrical properties of the conducting polymer polyaniline change greatly upon exposure to various chemicals. Specifically, polyaniline undergoes doping and dedoping chemistry with acids and bases that result in conductivity changes of over eight orders of magnitude. This large range in conductivity can be utilized to make polyaniline chemical sensors. Polyaniline nanofibers are chemically synthesized using a simple, template-free method that produces nanofibers with narrow size distributions. They are easily cast on microelectrode arrays and are shown to respond significantly better than conventional films to a number of different gases, such as acids, bases, hydrazine, and organic vapors. This is explained through their high surface area, small diameter, and porous nature of the nanofiber films that appear to allow better diffusion of vapors into the films. Polyaniline nanofibers disperse well in water and, as a result, have been used to make new composite materials with water soluble compounds, such as metal salts. These composite films can then be used to enhance sensing to gases that unmodified polyaniline would otherwise not be able to detect. For example, metal salt/polyaniline nanofiber composite films are used to enhance polyaniline's ability to sense hydrogen sulfide due to a reaction of the metal salt with hydrogen sulfide that releases a strong acid that then dopes the polyaniline, resulting in a significant increase in conductivity. The wide range in gas detection capabilities and the use of composite films makes polyaniline nanofibers versatile chemical sensor materials that have good potential for many chemical detection applications, including homeland security.
C-arm based cone-beam CT using a two-concentric-arc source trajectory: system evaluation (2008)

The current x-ray source trajectory for C-arm based cone-beam CT is a single arc. Reconstruction from data acquired with this trajectory yields cone-beam artifacts for regions other than the central slice. In this work we present the preliminary evaluation of reconstruction from a source trajectory of two concentric arcs using a flat-panel detector equipped C-arm gantry (GE Healthcare Innova 4100 system, Waukesha, Wisconsin). The reconstruction method employed is a summation of FDK-type reconstructions from the two individual arcs. For the angle between arcs studied here, 30°, this method offers a significant reduction in the visibility of cone-beam artifacts, with the additional advantages of simplicity and ease of implementation due to the fact that it is a direct extension of the reconstruction method currently implemented on commercial systems. Reconstructed images from data acquired from the two arc trajectory are compared to those reconstructed from a single arc trajectory and evaluated in terms of spatial resolution, low contrast resolution, noise, and artifact level.
The endocrine response to acute ghrelin administration is blunted in patients with anorexia nervosa, a ghrelin hypersecretory state (2004)

This study demonstrates that anorexia nervosa, a clinical condition of ghrelin hypersecretion, shows a specific reduction in the GH response to ghrelin, despite the hyper-responsiveness to GHRH administration. The impaired GH response to ghrelin in anorexia nervosa agrees with previous evidence of blunted GH response to synthetic GH secretagogues and could reflect desensitization of the GHS receptor induced by the chronic elevation of ghrelin levels in this pathological state.
Photonic integrated-circuit elements for phased-array steering systems (1992)

Progress will be presented regarding circuit elements to be eventually incorporated into a Photonic Integrated Circuit (PIC). Data from elements such as phase modulators and couplers will be reviewed. They have been developed employing ridge waveguides in MBE grown GaAs/AlGaAs material structures. A general approach to PICs will be discussed as well as their incorporation into optical frequency translation (OFT) modulation circuits for coherent optical systems. Detailed theoretical discussion of one, two, and four-arm phase-modulator-based OFT circuits is included.
E-Band Multi-Phase <i>LC</i> Oscillators With Rotated-Phase-Tuning Using Implicit Phase Shifters (2018)

A rotated-phase-tuning (RPT) technique is proposed for millimeter-wave (mmW) LC-based oscillators. Without using varactors, the oscillation frequency is tuned by phase interpolation to vary the phase of the current flowing into the LC tank. Interestingly, the intrinsic delay of transistors is leveraged to rotate the phases for interpolation and thus to optimize the oscillator's performance in terms of frequency tuning range and phase noise. Two E-band RPT oscillator prototypes are designed and implemented in a 65-nm CMOS process. The first one with four-phase output measures oscillation frequency from 67.8 to 81.4 GHz and phase noise of -108 to -113 dBc/Hz at 10-MHz offset, while consuming 13 to 25 mW from a 1-V supply. With similar power consumption, the second prototype featuring eight-phase output operates from 74.8 to 79 GHz and achieves phase noise of -116 to -118 dBc/Hz at 10-MHz offset. The four-phase and eight-phase oscillators occupy small core areas of 0.02 and 0.06 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , respectively.
Converting a positive operator-valued measure to a design for a measuring instrument on the laboratory bench (1997)

A known positive operator-valued measure (POVM) describing a desired receiver of quantum light states is converted into a description of parts - including a prism, beam splitters and detectors - arranged to make a laboratory instrument. The conversion is made in two stages. The first is a transparent example of Neumark's theorem, in which a two-dimensional (non-projective) POVM is converted into a Hermitian operator on a space of three dimensions. The second uses a known factorization of the Hermitian operator into a product of simpler operators, each a conventional description of an optical component. If the components behave according to their conventional descriptions, the receiver behaves in accord with the given POVM.
Synthesis of rare‐earth activated AlN and GaN powders via a three‐step conversion process (2008)

Abstract Using a three‐step solution method, we have successfully synthesized rare‐earth (RE) activated AlN, GaN, and pure GaAlN powders. Aluminium and/or gallium nitrates are first dissolved in water. For AlN:RE, rare‐earth nitrates converted from their corresponding oxides of Dy 3+ and Tm 3+ are then added to the precursor nitrate solution. The mixture is subsequently converted into Al(OH) 3 :RE by combining with aqueous NH 4 OH at room temperature. The product is then mixed with aqueous NH 4 F to form (NH 4 ) 3 AlF 6 :RE. The conversion process is complete when the hexafluoride compound is flushed with anhydrous ammonia to produce the final nitride product AlN:Dy 3+ ,Tm 3+ . GaN, GaN:Tb 3+ and GaAlN are synthesized similarly. Single phase, pure GaN and GaAlN formation has been confirmed. Dysprosium oxide has been observed in AlN:Dy 3+ , Tm 3+ . Oxygen concentration of approximately 4 at% has been measured in GaN powders, and is slightly higher in AlN powders. Spectroscopic measurements show clearly observable emission from Dy 3+ and Tm 3+ co‐activated AlN samples. In activated GaN samples, Tb 3+ emission has been observed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
In Vivo Kinematics for Fixed and Mobile-Bearing Posterior Stabilized Knee Prostheses (2004)

This is the first in vivo kinematic study to compare mobile-bearing with fixed-bearing prostheses in patients who had total knee arthroplasties. Femorotibial contact positions for 40 patients implanted with either a fixed-bearing or mobile-bearing prosthesis were analyzed using videofluoroscopy. Femorotibial contact paths were determined using a computer automated model-fitting technique. Nineteen of 20 patients in each group experienced posterior femoral rollback of their lateral condyles, with a mean of 3.6 and 3.7 mm for fixed-bearing and mobile-bearing prostheses respectively. Eighteen patients who had mobile-bearing prostheses and 17 patients with fixed-bearing knee prostheses experienced a normal pattern of axial rotation of 7.3 degrees and 4.1 degrees respectively. Eleven of 20 (55%) patients who had mobile-bearing prostheses implanted and eight of 20 (40%) patients who had fixed-bearing prostheses implanted did not experience femoral condylar lift-off. The remaining knees had condylar lift-off less than 2.4 mm for fixed-bearing prostheses and 1.7 mm for mobile-bearing prostheses, respectively. Patients who had mobile-bearing prostheses implanted experienced greater axial rotation and less condylar lift-off than patients who had fixed-bearing prostheses implanted. Both cruciate ligaments are sacrificed for the mobile and fixed-bearing total knee replacements. The results from the current study showed that, in both groups, the majority of patients experienced kinematics similar to those of a normal knee. However, the extent of lateral femoral condyle posterior rollback and the extent of axial rotation were less.
Identification, cloning, and sequencing of a fragment of Amsacta moorei entomopoxvirus DNA containing the spheroidin gene and three vaccinia virus-related open reading frames (1991)

Entomopoxvirus virions are frequently contained within crystalline occlusion bodies, which are composed of primarily a single protein, spheroidin, which is analogous to the polyhedrin protein of baculovirus. The spheroidin gene of Amsacta moorei entomopoxvirus was identified following the microsequencing of polypeptides generated from cyanogen bromide treatment of spheroidin and the subsequent synthesis of oligonucleotide hybridization probes. DNA sequencing of a 6.8-kb region of DNA containing the spheroidin gene showed that the spheroidin protein is derived from a 3.0-kb open reading frame potentially encoding a protein of 115 kDa. Three copies of the heptanucleotide, TTTTTNT, a sequence associated with early gene transcription in the vertebrate poxviruses, and four in-frame translational termination signals were found within 60 bp upstream of the putative spheroidin gene promoter (TAAATG). The spheroidin gene promoter region contains the sequence TAAATG, which is found in many late promoters of the vertebrate poxviruses and which serves as the site of transcriptional initiation, as shown by primer extension. Primer extension experiments also showed that spheroidin gene transcripts contain 5' poly(A) sequences typical of vertebrate poxvirus late transcripts. The 92 bases upstream of the initiating TAAATG are unusually A + T rich and contain only 7 G or C residues. An analysis of open reading frames around the spheroidin gene suggests that the colinear core of "essential genes" typical of the vertebrate poxviruses is absent in A. moorei entomopoxvirus.
Preparation of some phosphinylguanidine derivatives (1975)

ADVERTISEMENT RETURN TO ISSUEPREVArticlePreparation of some phosphinylguanidine derivativesCletus E. Morris and Leon H. ChanceCite this: J. Chem. Eng. Data 1975, 20, 4, 452–453Publication Date (Print):October 1, 1975Publication History Published online1 May 2002Published inissue 1 October 1975https://pubs.acs.org/doi/10.1021/je60067a023https://doi.org/10.1021/je60067a023research-articleACS PublicationsRequest reuse permissionsArticle Views45Altmetric-Citations2LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts
Context-aware communication (2003)

Describes the Mercury system, whereby a user of an electronic message service receives messages on a device and in a format appropriate to his context (travelling, in a meeting, etc.); and ConChat, whereby besides transmitting his message he automatically transmits contextual information such as his location, the number and identities of other people in the room, the room's ambient temperature, lighting, and sound, other applications and devices running in the room, his mood, his personal status (on the 'phone, out to lunch, etc), and any activity in the room.
Segmentation of arterial vessel wall motion to sub-pixel resolution using M-mode ultrasound (2008)

We describe a method for segmenting arterial vessel wall motion to sub-pixel resolution, using the returns from M-mode ultrasound. The technique involves measuring the spatial offset between all pairs of scans from their cross-correlation, converting the spatial offsets to relative wall motion through a global optimization, and finally translating from relative to absolute wall motion by interpolation over the M-mode image. The resulting detailed wall distension waveform has the potential to enhance existing vascular biomarkers, such as strain and compliance, as well as enable new ones.