1,721 research outputs found
A narrative-based collaborative writing tool for coherent technical documents
No full textOne important feature of an effective document that makes it easy to read and understand is known as coherence. Technical documents produced collaboratively are often incoherent due to a lack of group consensus and misaligned contributions by the individual authors. However, current document planning techniques and writing tools do not provide explicit support for improving coherence. The goal of this research, therefore, is to develop and evaluate a new technique and tool that helps teams of authors to structure coherent technical documents. The coherence of a document can be attributed to the story (or narrative) it conveys to the reader. If this story is consistent and coherent, the same can be said about the document. A discourse theory such as Rhetorical Structure Theory (RST) that has been developed by linguists helps further to analyse and improve a narrative. RST explains the coherence of a text by virtue of relationships (such as “paragraph A justifies paragraph B”) between parts of the text. This research has combined the ideas from these parallel strands of research to develop a new document planning technique called narrative-based writing. The method involves writing down an explicit précis of the story (called a document narrative or DN) and then analysing it using RST. The DN and RST analysis are then used to structure the eventual document. To extend the usability of narrative-based writing to geographically-dispersed authors, I have designed and implemented a collaborative tool that allows co-authors to edit, analyse and review DNs. The thorough design for the tool uses a combination of three models (conceptual, business process and functional) culminating in a set of functions that enable collaborative narrative-based writing. This dissertation discusses how, in the future, these functions could be incorporated in existing collaborative writing tools. Implementing this tool, albeit in its current prototypic state, has been invaluable in understanding the complexities of modelling and manipulating DNs and RST structures. Initial investigations using the new technique and tool have been positive, encouraging me to continue the research and evaluation in this field
Evaluatie suppleties Noord-Holland en Texel
No full textNote: NH-93.ANV002a.pdf bevat het hoofdrapport en NH-93.ANV002b.pdf bevat alle bijlagen. ----- De minister van Verkeer en Waterstaat heeft de kamer een interim-nota kustverdediging in 1993 toegezegd, waarin het kustverdedigingsbeleid wordt geëvalueerd. Een onderdeel van deze evaluatie is de evaluatie van de zandsuppleties. Om deze evaluatie uit te voeren is de werkgroep EVAZAND, onder leiding van de Dienst Getijdewateren, ingesteld. De evaluatie beperkt zich in principe tot de morfologische aspecten en is hoofdzakelijk gericht op het bepalen van de doelmatigheid of de effectiviteit van zandsuppleties. Omdat suppleties van 1990 of later zich vanwege de korte levensduur nauwelijks lenen voor evaluatie is een selectie gemaakt uit de suppleties van vóór 1990. Deze nota dient als de bijdrage van de Directie Noord-Holland aan het project EVAZAND en bevat de evaluatie van alle grote zandsuppleties van Noord-Holland en Texel van vóór 1990.EVAZAN
Dehydrogenation of the NH−NH Bond Triggered by Potassium tert-Butoxide in Liquid Ammonia
No full textA novel strategy for the dehydrogenation of NH-NH bond is disclosed using potassium t-butoxide (tBuOK) in liquid NH3 under air (O2) at room temperature. Its synthetic values are well demonstrated via highly efficient synthesis of aromatic azo compounds (up to 100% yield, 3 min), heterocyclic azo compounds, and dehydrazination of phenylhydrazine. The broad application of this strategy and its benefit to chemical biology is proved by a novel, convenient, one-pot and efficient synthesis of aliphatic diazirines, which are important photoreactive agents for photoaffinity labeling
cage by symmetric ligand architecture modification: insights into the ammonia gas sensing mechanism
No full textTwo Fe II complexes constructed through symmetric ligand architecture modification were utilized to systematically investigate the ammonia gas sensing mechanism through 57 Fe Mössbauer spectroscopy.The occurrence of spin crossover usually induces different outputs, one of which is the colour change, an essential parameter for a colorimetric sensor. Herein, by symmetric modification of the ligand architecture, two complexes: a Fe II (L1) 2 mononuclear high-spin (HS) complex (1) and a Fe II 4 (L2) 6 tetranuclear spin crossover cage (2) were constructed as colorimetric NH 3(g) sensors, operating in the solid state. The sensing process is accompanied by a remarkable colour change from reddish brown (1) or light purple (2) to dark grey at room temperature. 2 presents a shorter response time (90 s) to NH 3(g) compared to 1 (8 min) due to its empty cage structure, as revealed by single crystals X-ray diffraction, and large specific surface area increasing the adsorption rate of NH 3(g) . 57 Fe Mössbauer spectroscopy was employed to investigate the sensing mechanism around the metal centre. A conversion of 33% Fe II ions to the low-spin (LS) state was observed in 1@NH 3 , after the substitution of NH 3(g) molecules, leading to FeN 6 sites. The sensing mechanism of 2 also involves a HS to LS transition of Fe II ions induced with a new FeN 6 centre, but non-coordinated BF 4 − anions also react with NH 4 + to form NH 4 BF 4 . These findings provide a foundation for exploring Fe II -based coordination complexes as potential NH 3 gas sensors towards high nuclearity as well as tuneable porosity.Chinese Government Scholarship https://doi.org/10.13039/501100010890Deutsche Forschungsgemeinschaft https://doi.org/10.13039/501100001659Fonds De La Recherche Scientifique - FNRS https://doi.org/10.13039/501100002661Wallonie-Bruxelles International https://doi.org/10.13039/50110001097
Molecular tagging velocimetry of NH fluorescence in a high-enthalpy rarefied gas flow
No full textIn this paper a new type of molecular tagging velocimetry based on NH fluorescence was developed and validated for the velocity measurements of a high-enthalpy rarefied gas wind tunnel where the maximum flow velocity exceeds 6 km/ s near the nozzle exit at 0.2 Pa. The feasibility of this technique using the short-lived NH fluorescence was demonstrated in the hypersonic rarefied gas flow with yielding velocity profiles at multiple downstream locations from the nozzle exit. The total uncertainty of the measured flow velocities was estimated to be less than 6% when the flow velocity is above 2000 m/ s. For the new tagging technique only a single laser and a single time-gated camera are required for velocity measurement due to the existence of NH radicals in the arc-discharged-N2 mixed with a small amount of H-2. Therefore the NH-MTV not only shows great promise for tagging in high-enthalpy rarefied gas of nitrogen or air flows without seeding but also possesses high practicability and facility for velocity measurement
Un lema a revisar en Plinio, NH XXXII 149
No full textAt Plinius, NH XXXII 149, the author conjetures ...lepus... lupus... for ...elepris... lepus....No disponible
INTRAMOLECULAR NH \ldots N HYDROGEN BONDS
No full textAuthor Institution: Department of Chemistry, University of CalgarySpectroscopic evidence for intramolecular NH \ldots N hydrogen bonds in o-phenylenediamines, ethylenediamine, and the monocations of sparteine-and -isosparteine- N-oxides will be presented. Integrated intensity measurements, frequency measurements, and deuteration studies in the fundamental NH stretching region in dilute solution show evidence for intramolecular NH . . . N hydrogen bonds in o-phenylenediamines. Partial deuteration shows that the two NH bonds of a given amino group are nonequivalent, but that the two -NHD groups are identical, suggesting a conformation in which each amino group acts as both a proton donor and a proton acceptor. Similar studies on compounds where , etc., will be discussed with special reference to the conformation of ethylenediamine. In the monocations of sparteine- and -isosparteine-N-oxide the geometry of the system leads to very strong intramolecular hydrogen bonds, which remain unbroken even in dimethylsulphoxide solution
THE VALENCE STATES OF NH
No full textAuthor Institution: LOS Alamos Scientific Laboratory, University of CaliforniaTheoretical results from various levels of configuration interaction calculations are presented for the and states of the NH radical. In addition to spectroscopic constants for each state, dipole moments and transition moments between electronic states are reported
A study of the vacuum pyrolysis of para-substituted diazoacetophenones with He(I) ultraviolet photoelectron spectroscopy
No full textAn ultraviolet photoelectron (PE) spectrometer apparatus that utilizes a tuneable 50 W CW CO2 laser as a directed heat source was used to study the vacuum pyrolysis of diazoacetophenone (la) and its p-methyl, p-methoxy, p-chloro, and p-nitro analogues Ib, Ic, Id, and le. Analysis of the pyrolysate with He(I) ultraviolet PE spectroscopy shows that at a laser power Level of 26 W (500 +/- 50 degrees C) la, Ib, Ic, and Id, cleanly yield the corresponding phenylketenes 2a, 2b, 2c, and 2d, respectively, the products of the Wolff rearrangement of the incipient ketocarbenes. Of this group of highly reactive ketenes, which cannot be isolated in the condensed phase at ambient temperature, only 2a has been the subject of a previous PE spectroscopic study. But our work indicates that the sample of 2a prepared in the earlier study was impure. The low volatility of p-nitrodiazoacetophenone (le) thwarted our attempts to generate 2e and obtain its spectrum. Calculations at semiempirical (AMI) and ab inito (WF/G-31G(d)) levels of theory established that the diazoacetophenones prefer to adopt twisted syn conformations. That the calculated ionization potentials (HAM/3 and Becke3LYP/6-31+G(d)//HF/G-31G(d)) of la-ld and the synthesized PE spectra of la, Ib, and Ic correlate well with the PE spectroscopic data supports this finding. Shifts observed in the three low-energy ionizations of ketenes 26, 2c, and 2d induced by the para-substitution can be related to the character of the corresponding occupied molecular orbitals of phenylketene (2a).PT: J; CR: *HYP INC, 1994, HYPERCHEM 4 0 ALLEN AD, 1987, CAN J CHEM, V65, P1719 ANDRAOS J, 1991, J PHOTOCH PHOTOBIO A, V57, P165 ARDUENGO AJ, 1994, J AM CHEM SOC, V116, P6641 ASBRINK L, 1981, QCPE, V13, P393 BACHMANN C, 1990, J AM CHEM SOC, V112, P7488 BECKE AD, 1993, J CHEM PHYS, V98, P5648 CHMIELEWSKI D, 1993, CAN J CHEM, V71, P1741 CHONG DP, 1984, J PHYS CHEM-US, V88, P1479 COLBOURNE D, 1980, J CHEM SOC CHEM COMM, P250 COLBOURNE D, 1985, J CHEM SOC P2, P2049 FRISCH MJ, 1995, GAUSSIAN 94 REVISION HEHRE WJ, AB INITIO MOL ORBITA HOPE H, 1972, ACTA CRYSTALLOGR B, V28, P3632 HOTZEL A, 1980, ANGEW CHEM INT EDIT, V19, P739 KAPLAN F, 1966, J AM CHEM SOC, V88, P950 KIMURA K, 1981, HDB HEI PHOTOELECTRO KIRMSE W, 1994, ADV CARBENE CHEM, V1 KOOPMANS T, 1933, PHYSICA, V1, P104 MCMAHON RJ, 1985, J AM CHEM SOC, V107, P597 MCMAHON RJ, 1987, J AM CHEM SOC, V109, P2456 MODELLI A, 1980, J ELECT SPECTROSC RE, V18, P359 MOHMAND S, 1981, CHEM BER, V114, P2595 MUCHALL HM, IN PRESS TETRAHEDRON MUCHALL HM, 1997, CAN J CHEM, V75, P1851 MUCHALL HM, 1997, J MOL STRUCT, V435, P157 MUCHALL HM, 1998, CAN J CHEM, V76, P221 MUCHALL HM, 1998, CAN J CHEM, V76, P238 PATAI S, 1978, CHEM DIAZONIUM D 1 2 REGITZ M, 1968, CHEM BER, V101, P2622 SAMMYNAIKEN R, 1989, J CHEM SOC P2, P1987 STEWART JJP, 1983, QCPE, P455 STEWART JJP, 1986, AUSTIN MODEL 1 PACKA, P506 TROST BM, 1975, J AM CHEM SOC, V97, P2438 VOROBEV AS, 1993, RUSS CHEM B, V42, P281 WERSTIUK NH, 1992, CAN J CHEM, V70, P1971 WERSTIUK NH, 1994, CAN J CHEM, V72, P2537 WERSTIUK NH, 1994, J CHEM SOC FARADAY T, V90, P3383 WERSTIUK NH, 1995, CAN J CHEM, V73, P146 WERSTIUK NH, 1995, CAN J CHEM, V73, P1738 WERSTIUK NH, 1996, CAN J CHEM, V74, P1903 WERSTIUK NH, 1996, CAN J CHEM, V74, P2536 WERSTIUK NH, 1998, CAN J CHEM, V76, P672 WOLFF L, 1912, LIEBIGS ANN CHEM, V394, P23; NR: 44; TC: 8; J9: CAN J CHEM; PG: 12; GA: 143VNSource type: Electronic(1
FOURIER-TRANSFORM SPECTROSCOPY OF NH AND NH IN THE NEAR-INFRARED
No full textAuthor Institution: Laboratoire Interuniversitaire des Systemes Atmospheriques (LISA), CNRS and Universites Paris-7 et -12, Creteil, France; Laboratorio de Espectroscopia e Laser, Instituto de Fisica, Universidade Federal Fluminense, Niteroi, Rio de Janeiro, BrazilThe near-infrared absorption spectrum of NH is an interesting opportunity for atmospheric {\it in-situ} measurements of this species using tuneable diode-lasers. For this purpose, accurate line positions and intensities are indispensable. In the past, several studies of the absorption spectrum of NH in the near-infrared were carried out, using Fourier-transform and tuneable diode-laser spectroscopy. More recently, high-resolution diode-laser spectra of NH were analyzed for the first time. The lines of NH in this region are also useful for wavenumber calibration of absorption spectra obtained with tuneable lasers. In our group, we have recently investigated the possibility to detect atmospheric NH using photoacoustic laser spectroscopy in the 1.5 m region, and observed several discrepancies between individual line positions and intensities observed in our and previous studies, as already noticed by other groups. In order to solve this problem we have measured new absorption spectra of NH (and also of NH) in the 6300-7500 cm region using a Bruker IFS 120-HR Fourier-transform spectrometer. The length of the absorption cell was 30 cm. The NH pressures employed were around 30 mbar, and the spectral resolution used was 0.02 cm, leading to linewidths (Full-Width at Half-Maximum) of about 0.03 cm. Based on these spectra, we have produced a list of individual line positions and line intensities at 296 K. Comparisons with the previous studies will be presented. }, {\bf 162}, 230-245 (1993).} }, {\bf 40}, 2031-2042 (2004).} }, {\bf 45}, 31-45 (2004).} }, {\bf 28}, 59-66 (2004).} }, in press (2006).
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