gebhart/patrepeval huggingface dataset:
Structural characterization of GaN and GaAs<i>x</i>N1−<i>x</i> grown by electron cyclotron resonance-metalorganic molecular beam epitaxy (1994)

Electron cyclotron resonance-metalorganic molecular beam epitaxy has been used to deposit GaN and GaAsxN1−x layers on various substrates. This paper will report on the structural characterization of this material, as measured by x-ray diffraction and cross-sectional transmission electron microscopy. GaAsxN1−x layers grown on GaAs appear to be cubic while those grown on GaP are surprisingly hexagonal. The hexagonal phase is also observed under some growth conditions in material grown on GaAs, however, the cubic phase can be obtained by optimizing the parameters which affect the initial nucleation. Conditions such as pre-deposition annealing and growth temperature are critical in determining the phase and crystallinity of the resulting layers. Because of the reduced mismatch between GaN and GaP, the cubic phase of GaN can be more easily nucleated on GaP substrates than on GaAs wafers using similar growth conditions. However, the films under all growth conditions are fine-grained polycrystalline. The impact on film quality of various strain dissipation schemes, such as grading the group V species across the As (or P)–N interface, will also be discussed.
Variable-Temperature Microcrystal X-ray Diffraction Studies of Negative Thermal Expansion in the Pure Silica Zeolite IFR (2001)

Variable-temperature single-crystal X-ray diffraction using a synchrotron X-ray source has allowed the mechanism of negative thermal expansion in the pure silica zeolite IFR to be studied in greater detail than was previously possible over the temperature range 30-557 K. The results have allowed the changes in average atomic position with temperature to be measured and the structural features that are important in negative thermal expansion to be identified. The structure of zeolite IFR can be split into two regions: columns of fused rings that expand with temperature and the intercolumn regions, which tend to contract on heating. These competing changes combine to produce a material that contracts parallel to the crystallographic a and b axes and expands in the c-direction. Correlations between zeolite structure and thermal expansivity are also reported.
Acid‐catalyzed condensation of oleic acid into estolides and polyestolides (1994)

Abstract Oleic acid, when treated with 1.0 equivalent of perchloric acid at 50°C, produced a 76% yield of polyestolide. The concentration of mineral acid greatly affected the rate of estolide formation, with increased rates under high acid concentrations. Over a range of temperatures from room temperature to 100°C, reaction rates increased at higher temperatures. However, high acid concentrations and temperatures produced undesirable side products, primarily lactones. Other acids catalyze the condensation of oleic acid to form estolide with the following relative rates: HClO 4 >H 2 SO 4 > p ‐toluenesulfonic>BF 3 ·Et 2 O> montmorillonite K‐10>HCl>H 3 PO 4 , HNO 3 . Addition of water impedes the formation of estolide.
Upconversion Lasers (1992)

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 WILFRIED LENTH and ROGER M. MACFARLANE, "Upconversion Lasers," Optics & Photonics News 3(3), 8-15 (1992) Export Citation BibTex Endnote (RIS) HTML Plain Text Citation alert Save article
OSDF: An Intent-based Software Defined Network Programming Framework (2018)

Software Defined Networking (SDN) offers flexibility to program a network based on a set of network requirements. Programming the networks using SDN is not completely straightforward because a programmer must deal with low level details. To solve the problem, researchers proposed a set of network programming languages that provide a set of high level abstractions to hide low level hardware details. Most of the proposed languages provide abstractions related to packet processing and flows, and still require a programmer to specify low-level match-action fields to configure and monitor a network. Recently, in an attempt to raise the level at which programmers work, researchers have begun to investigate Intent-based, descriptive northbound interfaces. The work is still in early stages, and further investigation is required before intent-based systems will be adopted by enterprise networks. To help achieve the goal of moving to an intent-based design, we propose an SDN-based network programming framework, the Open Software Defined Framework (OSDF). OSDF provides a high level Application Programming Interface (API) that can be used by managers and network administrators to express network requirements for applications and policies for multiple domains. OSDF also provides a set of high level network operation services that handle common network configuration, monitoring, and Quality of Service (QoS) provisioning. OSDF is equipped with a policy conflict management module to help a network administrator detect and resolve policy conflicts. The paper shows how OSDF can be used and explains application-based policies. Finally, the paper reports the results of both testbed measurements and simulations that are used to evaluate the framework from multiple perspectives, including functionality and performance.
RNA regulatory element BLE1 directs the early steps of <i>bicoid</i> mRNA localization (1993)

Deployment of the bicoid morphogen gradient in early Drosophila embryos requires the prelocalization of bicoid mRNA to the anterior pole of the egg. This anterior localization is mediated by a cis-acting localization signal contained within the 3' untranslated region of the bicoid mRNA. Here we use a series of bicoid transgenes carrying small deletions in the 3' untranslated region to survey for functional elements that constitute the localization signal. We identify and characterize one essential element, BLE1, which specifically directs the early steps of localization. In addition, we find that many deletions within the bicoid mRNA 3' untranslated region impair but do not prevent localization. One such deletion specifically interferes with a later step in localization. Thus the bicoid mRNA localization signal appears to consist of multiple different elements, each responsible for different steps in the localization process.
Large-Scale Biomedical Image Analysis in Grid Environments (2008)

This paper presents the application of a component-based Grid middleware system for processing extremely large images obtained from digital microscopy devices. We have developed parallel, out-of-core techniques for different classes of data processing operations employed on images from confocal microscopy scanners. These techniques are combined into a data preprocessing and analysis pipeline using the component-based middleware system. The experimental results show that: 1) our implementation achieves good performance and can handle very large datasets on high-performance Grid nodes, consisting of computation and/or storage clusters and 2) it can take advantage of Grid nodes connected over high-bandwidth wide-area networks by combining task and data parallelism.
Optimal Aggregation of Money Supply Forecasts: Accuracy, Profitability and Market Efficiency (1983)

ABSTRACT We present a general procedure for aggregating expert forecasts which exploits regularities in the structure of information within the forecaster population. Specific information structures lead to aggregation methods which adjust for additive bias, differences in individual accuracy, and correlation among forecasts. As an application, we construct composite predictions of the weekly change in the money supply from forecasts made by twenty major securities dealers, for which high positive correlation is found to be a significant characteristic. Due to instability in the information structure, our methods cannot improve on the accuracy of a simple average in this case. However, they do capture information about the correlation among money supply forecasts which is not fully impounded in short‐term interest rates. Forecasts from our models accurately predict the direction of price changes for Treasury bills and Treasury bill futures after a money supply announcement.
Evidence for a transient inhibitory effect of insulin on GLUT2 expression in the liver: studies <i>in vivo</i> and <i>in vitro</i> (1993)

The glucose transporter GLUT2 is expressed predominantly in the liver. Previous studies have shown that glucose increases GLUT2 mRNA concentration in primary cultures of rat hepatocytes. Since insulin controls the glucose metabolism in the liver, it could be involved in the regulation of GLUT2 gene expression. In vivo, hyperinsulinaemia induced a transient inhibitory effect on liver GLUT2 gene expression, the maximal inhibition of GLUT2 mRNA concentration (93 +/- 6%) being observed after 6 h. When hyperglycaemia was associated with hyperinsulinaemia, the decrease in liver GLUT2 mRNA concentration was partially prevented. The respective effects of glucose and insulin were studied in vitro by primary culture of rat hepatocytes. Insulin alone exerted a transient inhibitory effect on GLUT2 mRNA concentration. When insulin and glucose (10-20 mM) were associated, the stimulatory effect of glucose on GLUT2 gene expression was predominant. In conclusion, the present study shows that GLUT2 mRNA concentration was conversely regulated by insulin and glucose, both in vitro and in vivo.
One-Step Nanoscale Assembly of Complex Structures via Harnessing of an Elastic Instability (2008)

We report on a simple yet robust method to produce orientationally modulated two-dimensional patterns with sub-100 nm features over cm2 regions via a solvent-induced swelling instability of an elastomeric film with micrometer-scale perforations. The dramatic reduction of feature size ( approximately 10 times) is achieved in a single step, and the process is reversible and repeatable without the requirement of delicate surface preparation or chemistry. By suspending ferrous and other functional nanoparticles in the solvent, we have faithfully printed the emergent patterns onto flat and curved substrates. We model this elastic instability in terms of elastically interacting "dislocation dipoles" and find complete agreement between the theoretical ground-state and the observed pattern. Our understanding allows us to manipulate the structural details of the membrane to tailor the elastic distortions and generate a variety of nanostructures.
Computed Tomography Coronary Artery Calcium Scoring (2012)

Cardiovascular risk factor-scoring algorithms may fall short in identifying asymptomatic individuals who will subsequently suffer a coronary event. It is generally thought that evaluation of the extent of the atherosclerotic plaque and total plaque burden can improve cardiovascular risk stratification. In the last decade, there has been an increasing interest in coronary calcium scoring by computed tomography. By determining the calcium score, an estimate of the total amount of coronary plaque is obtained. Numerous studies have shown that the calcium score predicts coronary heart disease. Recently, the calcium score was shown to improve risk stratification beyond cardiovascular risk factors, especially in those individuals deemed to be at intermediate risk. So far, only limited data exist on the cost-effectiveness of coronary calcium scoring in asymptomatic populations.
주택 전세-매매가격 비율에 반영된 미래자본이득 기대형성 메카니즘 (2011)

Investment, tenure choice, and other decisions related to houses largely depend on expectation on future price movement. However, few studies have investigated the nature of expectation formation since the test on market efficiency usually cannot be separated from the test on expectation formation. Unique quality of Seoul apartment market allows us to assume that the market is efficient. From the market equilibrium condition and employing CAPM, we construct series of expected required rate of returns from the apartment investment for each of 2,458 apartments. Then the part of return due to the expected capital gains is calculated, and compared with actual capital gains. We test whether various expectation hypotheses proposed in the literature can explain the relationship between the expected and the actual capital gains. The result shows that a particular version of the rational expectation hypothesis can explain the relationship for the majority of the apartments. No other hypotheses can be expectation formation mechanism for any meaningful number of apartments.
A reduced graphene oxide sound-emitting device: a new use for Joule heating (2013)

In our living environment, there are a lot of Joule heating sources around such as machines, chips, sunlight, etc. Joule heating has always been considered a useless power except in domestic appliances. Here, we report that Joule heating could be reused by reduced graphene oxide (rGO) to emit sound. Large-area free-standing rGO is demonstrated to emit sound under different radii of curvature. Tunable sound spectrum mappings are obtained by changing the radius of curvature. It was observed that decreasing the curvature radius could provide a better sound directivity. Theoretical simulations suggest that the mechanism is related to the thermoacoustic effect. Due to the excellent characteristics of flexibility and large area, this rGO sound-emitting device will open wide applications in environmental, biomedical and many other fields.
GaAs Solar Cells on Nanopatterned Si Substrates (2018)

Integrating III-Vs onto Si is a promising route toward tandem photovoltaics and cost mitigation of III-V substrates. While many III-V/Si photovoltaic integration approaches have been studied, epitaxial growth on Si allows for fewer processing steps compared to other approaches. However, current epitaxial pathways utilize expensive techniques, such as thermal cycle annealing or thick buffer layers to control defect densities, undermining the low-cost goal of integrating III-Vs with Si. Here, we present single-junction GaAs solar cells grown directly on Si using selective area growth as an alternative low-cost technique to control material quality with a much thinner buffer. We demonstrate a 10.4%-efficient GaAs device grown on a V-grooved Si substrate, which achieved an antiphase domain-free III-V/Si interface and a threading dislocation density of 2 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sup> cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> , despite the lack of a graded buffer. We compare this growth on V-grooved Si to solar cells grown on polished Si with and without a patterned silica buffer layer, which demonstrate efficiencies of 6.5% and 6.8%, respectively; the polished Si was patterned using nanoimprint lithography, which is a low-cost patterning technique compatible with III-V selective area growth. Cracking is found to be a critical challenge that hinders solar cell performance and is exacerbated by the V-grooved Si surface topography. The results in this paper provide a promising pathway toward high-efficiency, low-cost III-V/Si tandem photovoltaics.
Spontaneous development of protective anti-T cell receptor autoimmunity targeted against a natural EAE-regulatory idiotope located within the 39-59 region of the TCR-V beta 8.2 chain (1992)

The development of experimental autoimmune encephalomyelitis (EAE) in Lewis rats is mediated by V beta 8.2+ T cells specific for myelin basic protein. One consequence of this biased expression of V beta 8.2 is the spontaneous development of regulatory T cells and antibodies against residues 39-59 of the V beta 8.2 sequence. Moreover, a synthetic V beta 8.2-39-59 peptide could induce protection against and speed recovery from EAE. T cells and antibodies specific for V beta 8.2-39-59 could transfer protection from EAE. Recently, we reported that the protective T cell epitope is subsumed within the V beta 8-44-54 sequence. We now report that protection induced by V beta 8-44-54 lasted at least 102 days and produced "split tolerance," enhancing anti-myelin basic protein antibody titers but reducing anti-myelin basic protein T cell frequency. The shorter V beta 8-44-54 peptide induced a distinct set of antibodies that did not cross-react with the longer V beta 8.2-39-59 peptide, although both specificities could stain V beta 8.2+ T cells and were equally protective against EAE. However, the V beta 8.2-39-59 peptide, but not the V beta 8-44-54 peptide, would appear to represent the natural idiotope: antibodies to V beta 8.2-39-59 that develop spontaneously during EAE could be boosted to higher titers only by the V beta 8.2-39-59, but not by other TCR peptides from the V beta 8.2 sequence, including V beta 8-44-54 that contains the functional T cell epitope. These results suggest that natural processing of the TCR V beta-chain favors the formation of a peptide that resembles the V beta 8.2-39-59 sequence. The B cell epitope present on the V beta 8-44-54 sequence was evident only in the absence of residues 39-43 and 55-59, suggesting that the two peptides possess distinct conformations. However, the V beta 8-44-54 B cell epitope is most likely expressed on the V beta 8.2+ T cells, either as a low affinity determinant on the intact TCR alpha/beta heterodimer or as a cryptic epitope bound in the cleft of surface MHC molecules.
Faster algorithms for string matching problems: matching the convolution bound (2002)

In this paper we give a randomized O(nlogn)-time algorithm for the string matching with don't cares problem. This improves the Fischer-Paterson bound from 1974 and answers the open problem posed (among others) by Weiner and Galil. Using the same technique, we give an O(nlogn)-time algorithm for other problems, including subset matching, tree pattern matching, (general) approximate threshold matching and point set matching. As this bound essentially matches the complexity of computing of the fast Fourier transform which is the only known technique for solving problems of this type, it is likely that the algorithms are in fact optimal. Additionally the technique used for the threshold matching problem can be applied to the on-line version of this problem, in which we are allowed to preprocess the text and require to process the pattern in time sublinear in the text length. This result involves an interesting variant of the Karp-Rabin fingerprint method in which hash functions are locality-sensitive, i.e. the probability of collision of two words depends on the distance between them.
Multi-Element Analysis Based on an Automated On-Line Microcolumn Separation/Preconcentration System Using a Novel Sol-Gel Thiocyanatopropyl-Functionalized Silica Sorbent Prior to ICP-AES for Environmental Water Samples (2021)

A sol-gel thiocyanatopropyl-functionalized silica sorbent was synthesized and employed for an automated on-line microcolumn preconcentration platform as a front-end to inductively coupled plasma atomic emission spectroscopy (ICP-AES) for the simultaneous determination of Cd(II), Pb(II), Cu(II), Cr(III), Co(II), Ni(II), Zn(II), Mn(II), Hg(II), and V(II). The developed system is based on an easy-to-repack microcolumn construction integrated into a flow injection manifold coupled directly to ICP-AES's nebulizer. After on-line extraction/preconcentration of the target analyte onto the surface of the sorbent, successive elution with 1.0 mol L<sup>-1</sup> HNO<sub>3</sub> was performed. All main chemical and hydrodynamic factors affecting the effectiveness of the system were thoroughly investigated and optimized. Under optimized experimental conditions, for 60 s preconcentration time, the enhancement factor achieved for the target analytes was between 31 to 53. The limits of detection varied in the range of 0.05 to 0.24 μg L<sup>-1</sup>, while the limits of quantification ranged from 0.17 to 0.79 μg L<sup>-1</sup>. The precision of the method was expressed in terms of relative standard deviation (RSD%) and was less than 7.9%. Furthermore, good method accuracy was observed by analyzing three certified reference materials. The proposed method was also successfully employed for the analysis of environmental water samples.
Evaluation participative de la reforme des politiques dans le secteur agricole en Zambie (1998)

Since 1991, radical changes have taken place in the policy and institutional environment governing the agriculture sector in Zambia. Policies of liberalization and privatization have entailed the replacement of previously state-supplied agricultural services (notably credit, inputs supply and agricultural marketing) by private sector provision. The Agricultural Sector Investment Program (ASIP), assisted by the World Bank, provides the context for continuing agricultural policy development, as well as for the integration of previously fragmented projects and programs in the sector. ASIP is predicated upon participation in program design and implementation by the full range of stakeholders in the public, private and non-governmental sectors. As a means both of improving program implementation and of promoting the active participation of beneficiaries and other actors, ASIP has established systematic and regular feedback between policy makers and service providers, and those affected by programs, using methods such as Participatory Rural Appraisal.
An integrated air-gap-capacitor pressure sensor and digital readout with sub-100 attofarad resolution (1992)

The fabrication and characterization of an integrated air-gap-capacitor pressure sensor are presented. The capacitor fabrication process uses standard IC processing to create NMOS circuits, and an added polysilicon layer to create poly-to-n/sup +/ capacitors with a 0.6- mu m-thick dielectric using deposited oxide. Subsequent processing is used to produce deformable, parallel-plate, air-gap capacitors on the front side alongside MOS circuits. Sensor chips are fabricated using 100- mu m*100- mu m, 100-fF air-gap capacitors with on-chip circuitry. The sensor chip is a part of a capacitive measurement system that uses a charge-redistribution sense technique to achieve very high capacitance resolution. The behavior of the pressure sensor chips was studied as a function of applied pressure in the 0-240-kPa (0-35-psi) range. Measurements indicate a sensitivity of 0.93 mV/kPa (6.40 mV/psi) with a deflection of 10 nm/kPa (70 nm/psi) at 0-69 kPa (0-10 psi). Standard deviations indicate a static pressure resolution of 0.54 kPa (0.078 psi), which translates to 30 attofarads at a sampling frequency of 11 kHz.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>
Electrochemical synthesis of metal and semiconductor nano-disks using the STM (1993)

Metal (Cu, Ag, Cd, etc) and semiconductor (e.g., CdSe) nano-disks having diameters of {approx}100-200{angstrom} and heights of 20-40{angstrom} are synthesized in the STM by the reduction of metal ions at graphite and Si(111) surfaces. These structures are produced by confining the electrochemical reduction -- which generates either the semiconductor or metal as an insoluble product -- between the STM tip and sample surface. The spatial selectivity of the synthesis reaction derives from a unique two-step mechanism in which a reactive site (i.e., a defect) is produced at the point of tunneling on the sample surface within 5 {mu}sec of the application of a bias pulse. Nucleation of the semiconductor or metal phase is then observed to occur on the high coordination sites of the defect and the subsequent growth of this structure is diffusion limited. Nano-disks of group II-VI and group I-VII semiconductors are accessible using either of two synthetic approaches.