gebhart/patrepeval huggingface dataset:
Logic circuits using resonant-tunneling hot-electron transistors (RHETs) (1992)

A full adder and a 1/2 frequency divider using resonant-tunneling hot-electron transistors (RHETs) are proposed. These circuits make the best use of negative differential conductance, a feature of RHETs, and contain much fewer transistors than used in conventional circuits. They were fabricated using self-aligned InGaAs RHETs and WSiN thin film resistors on a single chip. The RHETs have an i-InGaAlAs/i-InGaAs collector barrier that improves the current gain at low collector-based voltages. Circuit operation was confirmed at 77 K with a supply voltage of 3 V.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>
Isolation and structure of halistatin 3 from the Western Pacific (Chuuk) marine sponge Phakellia sp (1995)

G. R. Pettit, Y. Ichihara, G. Wurzel, M. D. Williams, J. M. Schmidt and J. Chapuis, J. Chem. Soc., Chem. Commun., 1995, 383 DOI: 10.1039/C39950000383
Inverse scattering theory applied to the design of single-mode planar optical waveguides (1989)

An inverse scattering theory is used to design single-mode planar optical waveguides that have wider inhomogeneous cores than those obtained by direct scattering methods. The wave equation for the electric field in the core is transformed into a Schrödinger-type equation whose potential function q(x) is related to the refractive-index profile. The modal structure of the waveguide is characterized by the transverse reflection coefficient r(k); a single discrete propagating mode and continuous radiating modes are considered. The Gel’fand–Levitan–Marchenko inverse scattering theory is used to obtain the unique solution of q(x) from a rational-function representation of r(k).
Facile synthesis of quinine and related cinchona alkaloids (1972)

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFacile synthesis of quinine and related cinchona alkaloidsEdward C. Taylor and Stephen F. MartinCite this: J. Am. Chem. Soc. 1972, 94, 17, 6218–6220Publication Date (Print):August 1, 1972Publication History Published online1 May 2002Published inissue 1 August 1972https://pubs.acs.org/doi/10.1021/ja00772a062https://doi.org/10.1021/ja00772a062research-articleACS PublicationsRequest reuse permissionsArticle Views451Altmetric-Citations28LEARN 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
Polarimetric image processing: an important new tool for remote sensing (1990)

Whenever electromagnetic radiation is reflected from a surface, it becomes polarised to a degree, dependent upon surface structure, texture and angle of incidence. If the polarisation information from the reflected radiation is extracted from conventional intensity information by an imaging polarimeter it is possible to reveal detail about the surface that cannot be obtained by any other imaging technique. Hence, polarimetric images provide the means of observing objects and phenomena that are invisible to conventional imaging systems. An imaging polarimeter produces images representing the spatial variation in polarisation over the scene, which can be related to true texture, surface structure and material type. To date, polarimetric imagery has been completely neglected as a powerful, nonintrusive visual probing tool. Therefore, to provide an adequate perspective on the remote sensing capability of an imaging polarimeter, and how polarimetry could become an important technique for visual probing, the relevant theoretical basis for the processing of polarimetric images is presented.
Polymeric Capsules Prepared by in Situ Synthesis and Cross-Linking of Amphiphilic Copolymer by Atom Transfer Radical Polymerization (2003)

A technique for encapsulation of polar organic solvents using atom transfer radical polymerization (ATRP) by suspension polymerization was developed to encapsulate diphenyl ether (solubility parameter δ = 20.9 MPa1/2) for the first time. An amphiphilic terpolymer was prepared by suspension polymerization, by first preparing poly(methyl methacrylate-co-poly(ethylene glycol) methacrylate), P(MMA-co-PegMA), oligomers in solution conditions, followed by addition of a cross-linking monomer, diethylene glycol dimethacrylate, to the polymerization solution, and then transfer of this oil phase to a stirred aqueous phase. The thermodynamic requirement for encapsulation of polar core oils is that the polymer has low interfacial tensions with both the oil phase and the water phase. Therefore, increasing the polarity of the copolymer by increasing its PegMA content (0−31 mol %) led to a transition in suspension particle morphology from matrix to multihollow and hollow particles. Furthermore, particles prepared with similar monomer feed ratios by conventional free radical polymerization (CFRP) did not exhibit a multihollow structure. We attribute this difference in ATRP and CFRP suspension particle morphology to the slow rate of the ATRP reaction which allows sufficient time for diffusion of the forming polymer chains to the oil−water interface, resulting in the thermodynamically favored hollow particle morphology.
A Novel OFDMA-PON Architecture With Source-Free ONUs for Next-Generation Optical Access Networks (2009)

This letter proposes a novel architecture for next-generation passive optical networks based on the employment of orthogonal frequency-division multiple access. The key new feature of the proposed approach is source-free single-wavelength upstream transmission enabled by carrier suppression, which has been experimentally verified to achieve 10-Gb/s upstream throughput.
Molecular Pathophysiology of Myelodysplastic Syndromes (2011)

The clinicopathologic heterogeneity of myelodysplastic syndromes (MDS) is driven by diverse, somatically acquired genetic abnormalities. Recent technological advances have enabled the identification of many new mutations, which have implicated novel pathways in MDS pathogenesis, including RNA splicing and epigenetic regulation of gene expression. Molecular abnormalities, either somatic point mutations or chromosomal lesions, can be identified in the vast majority of MDS cases and underlie specific disease phenotypes. As the full array of molecular abnormalities is characterized, genetic variables are likely to complement standard morphologic evaluation in future MDS classification schemes and risk models.
Design of a Thermally-Actuated Gas Lift Safety Valve (2011)

Gas-lifted oil wells are susceptible to failure through malfunction of gas lift valve assemblies (GLV). One failure mode occurs when the GLV check valve fails and product passes into the well annulus, potentially reaching the wellhead. This is a growing concern as offshore wells are drilled thousands of meters below the ocean floor in extreme temperature and pressure conditions, and repair and monitoring become difficult. Currently no safeguard exists in the GLV to prevent product passage in the event of check valve failure. In this paper a design and operational procedures are proposed for a thermally-actuated positive-locking safety valve to seal the GLV in the event of check valve failure. A thermal model of the well and GLV system is developed and compared to well data to verify feasibility of a thermally-actuated safety valve. A 3× scale prototype safety valve is built and tested under simulated failure scenarios and well start-up scenarios. Realistic well temperatures in the range of 20C to 70C are used. Results demonstrate valve closure in response to simulated check valve failure and valve opening during simulated well start-up.
The Spectacle Lens Image Quality Mapper (1999)

Get PDF Email Share Share with Facebook Tweet This Post on reddit Share with LinkedIn Add to CiteULike Add to Mendeley Add to BibSonomy Get Citation Copy Citation Text J. B. Hadaway, R. A. Chipman, J. Drewes, and T. Hargrove, "The Spectacle Lens Image Quality Mapper," in Vision Science and its Applications, 1999 OSA Technical Digest Series (Optica Publishing Group, 1999), paper SuB3. Export Citation BibTex Endnote (RIS) HTML Plain Text Citation alert Save article
User Interaction Models for Disambiguation in Programming by Example (2015)

Programming by Examples (PBE) has the potential to revolutionize end-user programming by enabling end users, most of whom are non-programmers, to create small scripts for automating repetitive tasks. However, examples, though often easy to provide, are an ambiguous specification of the user's intent. Because of that, a key impedance in adoption of PBE systems is the lack of user confidence in the correctness of the program that was synthesized by the system. We present two novel user interaction models that communicate actionable information to the user to help resolve ambiguity in the examples. One of these models allows the user to effectively navigate between the huge set of programs that are consistent with the examples provided by the user. The other model uses active learning to ask directed example-based questions to the user on the test input data over which the user intends to run the synthesized program. Our user studies show that each of these models significantly reduces the number of errors in the performed task without any difference in completion time. Moreover, both models are perceived as useful, and the proactive active-learning based model has a slightly higher preference regarding the users' confidence in the result.
Generation and Control of Oblique Shocks Using Microjets (2011)

Jets in a supersonic crossflow are known to produce a three-dimensional bow-shock structure due to the blockage of the flow. In the present study, streamwise linear arrays of high-momentum microjets are used to generate either single or multiple oblique shocks in a supersonic crossflow. The shocks generated using microjets can be tailored in terms of their strength and be made either parallel or coalescing, depending on the application. Flow visualization
using shadowgraph and density field measurements using background-oriented schlieren (BOS) technique were
carried out for a range of microjet operating conditions. The results obtained using the two methods are consistent
and complementary and show a linear variation of oblique shock angles with a microjet pressure ratio over the range
of conditions tested. The density field obtained using BOS clearly shows the oblique shocks generated using these
microjet arrays, the jump in density across the shock, the extent of the high-density field, the expansion fan, and the
associated decrease in density. The results suggest that microjet arrays can be successfully used to develop techniques for sonic boom mitigation and high-performance supersonic inlets.
The leukotriene B<sub>4</sub>receptor functions as a novel type of coreceptor mediating entry of primary HIV-1 isolates into CD4-positive cells (1998)

The recently cloned human chemoattractant receptor-like (CMKRL)1, which is expressed in vivo in CD4-positive immune cells, has structural homology with the two chemokine receptors C-C chemokine receptor (CCR)5 and C-X-C chemokine receptor (CXCR)4, which serve as the major coreceptors necessary for fusion of the HIV-1 envelope with target cells. In view of the structural similarity, CMKRL1 was tested for its possible function as another HIV-1 coreceptor after stable expression in murine fibroblasts bearing the human CD4 receptor. The cells were infected with 10 primary clinical isolates of HIV-1, and entry was monitored by semiquantitative PCR of viral DNA. The efficiency of the entry was compared with the entry taking place in CD4-positive cells expressing either CCR5 or CXCR4. Seven of the isolates used CMKRL1 for viral entry; they were mainly of the syncytium-inducing phenotype and also used CXCR4. Entry efficiency was higher with CMKRL1 than with CXCR4 for more than half of these isolates. Three of the ten isolates did not use CMKRL1; instead, entry was mediated by both CCR5 and CXCR4. The experiments thus indicate that CMKRL1 functions as a coreceptor for the entry of HIV-1 into CD4-positive cells. In the course of this study, leukotriene B4 was shown to be the natural ligand for this receptor (now designated BLTR), which therefore represents a novel type of HIV-1 coreceptor along with the previously identified chemokine receptors. BLTR belongs to the same general chemoattractant receptor family as the chemokine receptors but is structurally more distant from them than are any of the previously described HIV-1 coreceptors.
Broadband division-of-amplitude polarimeter based on uncoated prisms (1998)

A broadband division-of-amplitude polarimeter (DOAP) is presented. It can provide the real-time measurement of any state of polarization of light, described by its Stokes vector, in large spectral windows. The light is split first into two beams by a prism and then into four beams by means of any polarizer device that will separate the two linear orthogonal states of polarization. Finally, the Stokes vector is directly deduced from the four measured intensities. To avoid interference effects, the splitting of light into four beams is induced only by refractive-index contrast effects between semi-infinite media that are weakly dependent on the wavelength. An experimental setup working from 0.4 to 2 mum is described. It provides similar sensitivities for all the states of polarization, and its characteristics are constant, on a scale of a few percent, within the spectral window. Calibrations performed at 458 and 633 nm display good agreement between theoretical and experimental values. The accuracy of the prism DOAP, evaluated by measurement of the Stokes vector produced by a rotating Glan polarizer, is better than 1%. An infrared extension of this polarimeter is also presented.
Coverage Analysis and Load Balancing in HetNets With Millimeter Wave Multi-RAT Small Cells (2018)

We characterize a two tier heterogeneous network, consisting of classical sub-6 GHz macro cells, and multi radio access technology (RAT) small cells able to operate in sub-6 GHz and millimeter-wave (mm-wave) bands. For optimizing coverage and to balance loads, we propose a two-step mechanism based on two biases for tuning the tier and RAT selection, where the sub-6 GHz band is used to speed-up the initial access procedure in the mm-wave RAT. First, we investigate the effect of the biases in terms of signal-to-interference-plus-noise ratio (SINR) distribution, cell load, and user throughput. More specifically, we obtain the optimal biases that maximize either the SINR coverage or the user downlink throughput. Then, we characterize the cell load using the mean cell approach and derive upper bounds on the overloading probabilities. Finally, for a given traffic density, we provide the small cell density required to satisfy system constraints in terms of overloading and outage probabilities. Our analysis highlights the importance of deploying dual-band small cells, in particular, when small cells are sparsely deployed or in case of heavy traffic.
Visible photoelectrochemical water splitting into H <sub>2</sub> and O <sub>2</sub> in a dye-sensitized photoelectrosynthesis cell (2015)

A hybrid strategy for solar water splitting is exploited here based on a dye-sensitized photoelectrosynthesis cell (DSPEC) with a mesoporous SnO2/TiO2 core/shell nanostructured electrode derivatized with a surface-bound Ru(II) polypyridyl-based chromophore-catalyst assembly. The assembly, [(4,4'-(PO3H2)2bpy)2Ru(4-Mebpy-4'-bimpy)Ru(tpy)(OH2)](4+) ([Ru(a) (II)-Ru(b) (II)-OH2](4+), combines both a light absorber and a water oxidation catalyst in a single molecule. It was attached to the TiO2 shell by phosphonate-surface oxide binding. The oxide-bound assembly was further stabilized on the surface by atomic layer deposition (ALD) of either Al2O3 or TiO2 overlayers. Illumination of the resulting fluorine-doped tin oxide (FTO)|SnO2/TiO2|-[Ru(a) (II)-Ru(b) (II)-OH2](4+)(Al2O3 or TiO2) photoanodes in photoelectrochemical cells with a Pt cathode and a small applied bias resulted in visible-light water splitting as shown by direct measurements of both evolved H2 and O2. The performance of the resulting DSPECs varies with shell thickness and the nature and extent of the oxide overlayer. Use of the SnO2/TiO2 core/shell compared with nanoITO/TiO2 with the same assembly results in photocurrent enhancements of ∼ 5. Systematic variations in shell thickness and ALD overlayer lead to photocurrent densities as high as 1.97 mA/cm(2) with 445-nm, ∼ 90-mW/cm(2) illumination in a phosphate buffer at pH 7.
Air-bridge microcavities (1995)

We introduce and analyze a new type of high-Q microcavity consisting of a channel waveguide and a one-dimensional photonic crystal. A band gap for the guided modes is opened and a sharp resonant state is created by adding a single defect in the periodic system. An analysis of the eigenstates shows that strong field confinement of the defect state can be achieved with a modal volume less than half of a cubic half-wavelength. We also present a feasibility study for the fabrication of suspended structures with micron-sized features using semiconductor materials.
Minimal realizations of spatial stiffnesses with parallel or serial mechanisms having concurrent axes (2001)

Abstract This article presents a new method for the synthesis of an arbitrary spatial elastic behavior with an elastic mechanism. The mechanisms considered are parallel and serial mechanisms with concurrent axes. We show that any full‐rank spatial stiffness matrix can be realized using a parallel mechanism with all spring axes intersecting at a unique point. It is shown that this intersection point must be the center of stiffness. We also show that any full‐rank spatial compliance matrix can be realized using a serial mechanism with all joint axes intersecting at a unique point. This point is shown to be the center of compliance. Synthesis procedures for mechanisms with these properties are provided. The realizations are shown to be minimal in the sense that both the number of screw components and the total number of components are minimum. © 2001 John Wiley & Sons, Inc.
Dissection of experimental asthma with DNA microarray analysis identifies arginase in asthma pathogenesis (2003)

Asthma is on the rise despite intense, ongoing research underscoring the need for new scientific inquiry. In an effort to provide unbiased insight into disease pathogenesis, we took an approach involving expression profiling of lung tissue from mice with experimental asthma. Employing asthma models induced by different allergens and protocols, we identified 6.5% of the tested genome whose expression was altered in an asthmatic lung. Notably, two phenotypically similar models of experimental asthma were shown to have distinct transcript profiles. Genes related to metabolism of basic amino acids, specifically the cationic amino acid transporter 2, arginase I, and arginase II, were particularly prominent among the asthma signature genes. In situ hybridization demonstrated marked staining of arginase I, predominantly in submucosal inflammatory lesions. Arginase activity was increased in allergen-challenged lungs, as demonstrated by increased enzyme activity, and increased levels of putrescine, a downstream product. Lung arginase activity and mRNA expression were strongly induced by IL-4 and IL-13, and were differentially dependent on signal transducer and activator of transcription 6. Analysis of patients with asthma supported the importance of this pathway in human disease. Based on the ability of arginase to regulate generation of NO, polyamines, and collagen, these results provide a basis for pharmacologically targeting arginine metabolism in allergic disorders.
P‐28: Contrast Enhancement for Imaging System using Electrically Tunable Liquid Crystal Lens (2015)

A method of improving the image quality of an optical system using liquid crystal lens is proposed and demonstrated by experiments. Because image magnification is invariant with liquid crystal lens imaging, an image processing using focused and defocused images can be done to enhance the contrast of the focused image.
An <i>ab initio</i> procedure for deriving atomic polarizability tensors in molecules (2001)

A new method for deriving anisotropic atomic dipole polarizability tensors for predicting molecular polarizabilities is presented. The procedure uses the relationships between atomic and molecular multipoles to rigorously derive the atomic polarizability tensors from quantum mechanically computed molecular dipole–quadrupole polarizabilities and their derivatives with respect to molecular deformations. The resulting atomic polarizabilities have been tested for the water molecule at several ab initio levels of approximation by comparing the summed atomic polarizabilities with the conventional ab initio molecular results and with experiment. Good agreement was found between molecular polarizabilities found using the two methods. The model is also shown to give interaction energies between a water molecule and a point charge that accurately reproduce ab initio results. A similar comparison of the atomic polarizability tensors is shown for the N-methylacetamide molecule. For most atom types, the atomic polarizability tensors were found to be significantly anisotropic, indicating that this method can significantly improve on the isotropic approximation for predicting molecular properties that depend strongly on polarization effects.
Nanocrystal in dendron-box: a versatile solution to the chemical, photochemical, and thermal instability of colloidal nanocrystals (2003)

This account summarizes the recent development of dendron and dendron-box stabilized nanocrystals (dendron-nanocrystals and box-nanocrystals) by Peng’s research group. The rationale, the design of the dendron ligands, and the strategies for the formation of a box-nanocrystal are all discussed. The superior stability of the box-nanocrystal against harsh chemical, photochemical and thermal treatments is discussed. Two examples of the applications of box-nanocrystals are given. A brief perspective is provided for the future development of this emerging research area.