Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 13 de 13
Filter
Add more filters










Publication year range
1.
Data Brief ; 32: 106042, 2020 Oct.
Article in English | MEDLINE | ID: mdl-32775562

ABSTRACT

Patent bibliometrics data are the most reliable business performance metric for applied research and development activities when investigating the knowledge domains or the technological evolution of vehicle powertrain technologies in the automotive industry. Our paper describes a global patents dataset for the internal combustion engine vehicles (ICEV), hybrid electric vehicles (HEV) and battery electric vehicles (BEV) over 1985-2016. We extracted the patents granted in each powertrain field from Thomson Reuters' Derwent Innovations Index (DII). We applied a combined search strategy of international patent classifications (IPCs) and keywords as well as 'patent families' and 'priority dates' to construct our global patents dataset. This strategy returned a total of 78,732 patents, within which we identified 49,154 ICEV patents; 10,888 HEV patents; and 18,690 BEV patents. Our database includes numerous descriptive features of each patent such as title, abstract, claim, priority, application and publication dates, IPCs, assignees/applicants, inventors, and cited references. These data are associated with the research article 'The evolution of dynamic interactions between the knowledge development of powertrain systems' [1]. The full dataset, which is attached to this article, may be useful to both researchers and practitioners interested in investigating, modelling or forecasting the complexity and evolution of the technical and knowledge domains of the vehicle powertrains, across a variety of instruments such as social network analysis and regression models.

2.
Data Brief ; 28: 105017, 2020 Feb.
Article in English | MEDLINE | ID: mdl-31909116

ABSTRACT

The emergence of networks is a crucial channel for automotive organisations to build and diffuse the required environmental innovations in the transportation sector and accelerate the transition to the green mobility economy. This article contains the dataset regarding the global patents networks shaped both within and between the three vehicle powertrains of internal combustion engine vehicle (ICEV), hybrid electric vehicle (HEV) and battery electric vehicle (BEV) for the period of 1985-2016. The data was acquired from Thomson Reuters' Derwent Innovations Index (DII) platform using the elements of 'patent families' and 'priority dates'. We describe the dataset for the three major automotive periods of 'towards sustainable mobility' (1985-1996), 'towards hybridisation' (1997-2007), and 'towards mass commercialisation' (2008-2016). The dataset bears on two levels, individual and mutual, and we used a separate combined search strategy of keywords and IPCs codes (international patent classification) for each level. At individual level, we explored the internal network features of each powertrain individually (i.e. ICEV, HEV, and BEV). Monitoring a total of 78,732 patents in the three individual powertrain networks, we discovered a total of 1856 unique parent organisations connecting vis-à-vis 5849 bilateral relationships and operating around 4450 joint patents. At mutual level, we explored the mutually common network features of the powertrains (i.e. ICEV-HEV, HEV-BEV, and BEV-ICEV). Monitoring a total of 4702 patents in the three mutual powertrain networks, we discovered a total of 102 unique parent organisations connecting vis-à-vis 384 bilateral relationships and operating around 303 joint patents. These organisations were found specialised around 435 unique subgroup-level IPC codes, of which 134 codes were related to environmentally friendly innovations. The dataset presented in this article is used in [1] and allows researchers not only to map and model the network dynamics and structures within and between the powertrains at global level, but also to analyse and forecast their knowledge flows, technical domains and environmental innovations aspect, using a wide range of models such as social network analysis or regression.

3.
Auton Neurosci ; 203: 41-50, 2017 Mar.
Article in English | MEDLINE | ID: mdl-28010995

ABSTRACT

Our aim was to expand knowledge of cybersickness - a subtype of motion sickness provoked by immersion into a moving computer-generated virtual reality. Fourteen healthy subjects experienced a 15-min rollercoaster ride presented via a head-mounted display (Oculus Rift), for 3 consecutive days. Heart rate, respiration, finger and forehead skin conductance were measured during the experiment; this was complemented by a subjective nausea rating during the ride and by Motion Sickness Assessment Questionnaire before, immediately after and then 1, 2 and 3h post-ride. Physiological measurements were analysed in three dimensions: ride time, association with subjective nausea rating and experimental day. Forehead, and to a lesser extent finger phasic skin conductance activity showed a correlation with the reported nausea ratings, while alteration in other measured parameters were mostly related to autonomic arousal during the virtual ride onset. A significant habituation was observed in subjective symptom scores and in the duration of tolerated provocation. The latter increased from 7.0±1.3min on the first day to 12.0±2.5min on the third day (p<0.05); this was associated with a reduced slope of nausea rise from 1.3±0.3units/min on the first to 0.7±0.1units/min on the third day (p<0.01). Furthermore, habituation with repetitive exposure was also determined in the total symptom score post-ride: it fell from 1.6±0.1 on the first day to 1.2±0.1 on the third (p<0.001). We conclude that phasic changes of skin conductance on the forehead could be used to objectively quantify nausea; and that repetitive exposure to provocative VR content results in habituation.


Subject(s)
Autonomic Nervous System/physiopathology , Motion Sickness/physiopathology , User-Computer Interface , Adult , Analysis of Variance , Arousal/physiology , Electrocardiography , Female , Fingers/physiopathology , Forehead/physiopathology , Galvanic Skin Response , Habituation, Psychophysiologic , Heart Rate , Humans , Male , Respiration , Severity of Illness Index , Surveys and Questionnaires , Time Factors , Young Adult
4.
Physiol Behav ; 151: 583-90, 2015 Nov 01.
Article in English | MEDLINE | ID: mdl-26340855

ABSTRACT

Evidence from studies of provocative motion indicates that motion sickness is tightly linked to the disturbances of thermoregulation. The major aim of the current study was to determine whether provocative visual stimuli (immersion into the virtual reality simulating rides on a rollercoaster) affect skin temperature that reflects thermoregulatory cutaneous responses, and to test whether such stimuli alter cognitive functions. In 26 healthy young volunteers wearing head-mounted display (Oculus Rift), simulated rides consistently provoked vection and nausea, with a significant difference between the two versions of simulation software (Parrot Coaster and Helix). Basal finger temperature had bimodal distribution, with low-temperature group (n=8) having values of 23-29 °C, and high-temperature group (n=18) having values of 32-36 °C. Effects of cybersickness on finger temperature depended on the basal level of this variable: in subjects from former group it raised by 3-4 °C, while in most subjects from the latter group it either did not change or transiently reduced by 1.5-2 °C. There was no correlation between the magnitude of changes in the finger temperature and nausea score at the end of simulated ride. Provocative visual stimulation caused prolongation of simple reaction time by 20-50 ms; this increase closely correlated with the subjective rating of nausea. Lastly, in subjects who experienced pronounced nausea, heart rate was elevated. We conclude that cybersickness is associated with changes in cutaneous thermoregulatory vascular tone; this further supports the idea of a tight link between motion sickness and thermoregulation. Cybersickness-induced prolongation of reaction time raises obvious concerns regarding the safety of this technology.


Subject(s)
Heart Rate , Motion Sickness/etiology , Motion Sickness/physiopathology , Reaction Time , Skin Temperature , User-Computer Interface , Adolescent , Adult , Female , Fingers/physiopathology , Forearm/physiopathology , Humans , Male , Nausea/etiology , Nausea/physiopathology , Photic Stimulation/adverse effects , Random Allocation , Tachycardia/etiology , Tachycardia/physiopathology , Young Adult
5.
J Am Chem Soc ; 133(51): 20735-7, 2011 Dec 28.
Article in English | MEDLINE | ID: mdl-22126391

ABSTRACT

The synthesis of pure δ-MoN with desired superconducting properties usually requires extreme conditions, such as high temperature and high pressure, which hinders its fundamental studies and applications. Herein, by using a chemical solution method, epitaxial δ-MoN thin films have been grown on c-cut Al(2)O(3) substrates at a temperature lower than 900 °C and an ambient pressure. The films are phase pure and show a T(c) of 13.0 K with a sharp transition. In addition, the films show a high critical field and excellent current carrying capabilities, which further prove the superior quality of these chemically prepared epitaxial thin films.

6.
J Am Chem Soc ; 131(9): 3307-16, 2009 Mar 11.
Article in English | MEDLINE | ID: mdl-19219982

ABSTRACT

A new redox-active, tris(amido) ligand platform, bis(2-isopropylamino-4-methoxyphenylamine [NNN(cat)](3-), has been prepared and used in the preparation of tantalum(V) complexes. The ligand was prepared in its protonated form by a three-step procedure from commercially available 4-methoxy-2-nitroaniline and 1-iodo-4-methoxy-2-nitrobenzene. Direct reaction of [NNN(cat)]H(3) with TaCl(2)Me(3) afforded five-coordinate [NNN(cat)]TaCl(2) (1), which accepted the strong sigma-donor ligand (t)BuNC to form the six-coordinate adduct [NNN(cat)]TaCl(2)(CN(t)Bu) (2). Complex 1 is formally a d(0), Ta(V) complex; however, one- and two-electron reactivity is enabled at the metal center by the redox-activity of the ligand platform. Complex 1 was oxidized by one electron to afford the radical species [NNN(sq*)]TaCl(3) (3), which was characterized by solution EPR spectroscopy. Cyclic voltammetry studies of complex 3 showed clean one-electron oxidation and reduction processes at 0.148 and -0.324 V vs [Cp(2)Fe](+/0), indicating the accessibility of three oxidation states, [NNN(cat)](3-), [NNN(sq*)](2-), and [NNN(q)](-), for the metallated ligand. Complex 1 also can undergo two-electron reactions, as evidenced by the reaction with nitrene transfer reagents to form tantalum imido species. Thus 1 reacted with organic azides, RN(3) (R = Ph, p-C(6)H(4)Me, p-C(6)H(4)(t)Bu), to form [NNN(q)]TaCl(2)(NR) (4). Similarly, the tantalum diphenylmethylidenehydrazido complex, [NNN(q)]TaCl(2)(NNCPh(2)) (5), was formed by reaction of 1 with the diazoalkane, N(2)CPh(2).


Subject(s)
Amines/chemistry , Electrons , Organometallic Compounds/chemical synthesis , Tantalum/chemistry , Ligands , Molecular Structure , Organometallic Compounds/chemistry , Oxidation-Reduction
7.
Inorg Chem ; 47(22): 10522-32, 2008 Nov 17.
Article in English | MEDLINE | ID: mdl-18937444

ABSTRACT

An isostructural series of titanium, zirconium, and hafnium complexes, M[ap] 2L 2 (M = Ti, Zr, Hf; L = THF, pyridine), of the redox-active 4,6-di- tert-butyl-2- tert-butylamidophenolate ligand ([ap] (2-)) have been prepared. The zirconium and hafnium derivatives react readily with halogen oxidants such as XeF 2, PhICl 2, and Br 2, leading to products in which one-electron oxidation of each [ap] (2-) ligand accompanies halide addition to the metal center. Iodine proved to be too weak of an oxidant to yield the corresponding oxidative addition product, and under no conditions could halogen oxidative addition products be obtained for titanium. According to X-ray crystallographic studies, the zirconium and hafnium oxidation products are best formulated as MX 2[isq.] 2 ([isq.] (-) = 4,6-di- tert-butyl-2- tert-butylimino-semiquinonate; M = Zr, Hf; X = F, Cl, Br) species, in which the molecule is symmetric with each redox-active ligand in the semiquinone oxidation state. Temperature-dependent magnetization measurements suggest a singlet ( S = 0) ground-state for the diradical complexes with a thermally accessible triplet ( S = 1) excited state. Solution electron paramagnetic resonance (EPR) spectra are consistent with this assignment, showing both Delta m s = 1 and Delta m s = 2 transitions for the antiferromagnetically coupled electrons.

8.
J Am Chem Soc ; 130(13): 4364-74, 2008 Apr 02.
Article in English | MEDLINE | ID: mdl-18331029

ABSTRACT

The new complex, [Zr(pda)2]n (1, pda2- = N,N'-bis(neo-pentyl)-ortho-phenylenediamide, n = 1 or 2), prepared by the reaction of 2 equiv of pdaLi2 with ZrCl4, reacts rapidly with halogen oxidants to afford the new product ZrX2(disq)2 (3, X = Cl, Br, I; disq- = N,N'-bis(neo-pentyl)-ortho-diiminosemiquinonate) in which each redox-active ligand has been oxidized by one electron. The oxidation products 3a-c have been structurally characterized and display an unusual parallel stacked arrangement of the disq- ligands in the solid state, with a separation of approximately 3 A. Density functional calculations show a bonding-type interaction between the SOMOs of the disq- ligands to form a unique HOMO while the antibonding linear combination forms a unique LUMO. This orbital configuration leads to a closed-shell-singlet ground-state electron configuration (S = 0). Temperature-dependent magnetism measurements indicate a low-lying triplet excited state at approximately 750 cm-1. In solution, 3a-c show strong disq--based absorption bands that are invariant across the halide series. Taken together these spectroscopic measurements provide experimental values for the one- and two-electron energies that characterize the pi-stacked bonding interaction between the two disq- ligands.


Subject(s)
Halogens/chemistry , Organometallic Compounds/chemistry , Zirconium/chemistry , Crystallography, X-Ray , Ligands , Models, Chemical , Models, Molecular , Molecular Structure , Organometallic Compounds/chemical synthesis , Oxidation-Reduction , Quantum Theory , Temperature
9.
J Am Chem Soc ; 130(9): 2728-9, 2008 Mar 05.
Article in English | MEDLINE | ID: mdl-18266370

ABSTRACT

Two-electron reactivity of [N2O2red]ZrL3 (1a, N2O2(red) = N,N'-bis(3,5-di-tert-butyl-2-phenoxy)-1,2-phenylenediamide, L = THF) was explored with halogens and 1,2-diphenylhydrazine. Despite a formal d0 zirconium(IV) metal center, halogen oxidative addition occurred to form [N2O2(ox)]ZrCl2(THF) (2) with two-electron oxidation of the ligand. This ligand redox activity allows catalytic reactivity with 1,2-diphenylhydrazine resulting in disproportionation to form aniline and azobenzene via a putative zirconium-imide intermediate.

10.
Inorg Chem ; 47(1): 265-73, 2008 Jan 07.
Article in English | MEDLINE | ID: mdl-18052370

ABSTRACT

The synthesis, characterization, and solution behavior of a series of six-coordinate zirconium(IV) dianions [ZrX2(ap)2]2- (ap = 2,4-di-tert-butyl-6-(tert-butylamido)phenolate; X = Ph, 3a; X = p-tolyl, 3b; X = Me, 4; X = NMe2, 5) are described. Complexes 3-5 were prepared by treating the neutral zirconium complex Zr(ap)2(THF)2 (1) with 2 equiv of LiX or by the direct reaction of apLi2 and LiX with ZrCl4. The complexes were isolated as lithium-etherate salts, and they were characterized by NMR spectroscopy and single-crystal X-ray diffraction. In non-coordinating solvents such as benzene-d6, complexes 3-5 are robust in solution, but in coordinating solvents such as THF-d8, dissociation of LiX was observed. The rate of LiX loss was evaluated by exchange reactions; the reaction rate constants span nine orders of magnitude at 298 K, with the slowest reaction being the dissociation of PhLi from 3a (tau1/2 = 4 h) and the fastest reaction being the dissociation of LiNMe2 from 5 (tau1/2 = 53 mus). In the case of LiNMe2 dissociation from 5, activation parameters suggest that the rate-determining step is purely dissociative; however, for diphenyl and dimethyl complexes 3a and 4, respectively, activation parameters suggest a solvent-assisted rate-determining step.

11.
Optometry ; 77(1): 17-22, 2006 Jan.
Article in English | MEDLINE | ID: mdl-16458242

ABSTRACT

BACKGROUND: The purpose of this study was to survey Diplomates in the Section on Cornea and Contact Lenses of the American Academy of Optometry (AAO) to determine their fitting preferences for astigmatic patients, lens materials used, and their perception of simplicity or complexity of bitoric fitting. METHODS: A total of 180 practitioners, representing all active Diplomates in the Cornea and Contact Lens Section, were sent a survey of 11 questions pertaining to their astigmatic contact lens prescribing habits. Sixty-eight (38%) of those surveyed responded to the questionnaire. RESULTS: The results of this survey included the following: (1) gas permeable (GP) lenses represented 28.7% of all contact lenses fit; (2) a spherical power effect (SPE) bitoric lens was preferred (versus four other options) by 58.8% of respondents for a 3.5 diopter (D) refractive astigmat with no residual astigmatism, whereas a cylinder power effect (CPE) bitoric was preferred by 55.9% for a 3.5 D refractive astigmatic with more than 1 D of residual astigmatism; (3) only 10.4% of responding practitioners consider GP torics to be difficult to fit. CONCLUSIONS: (1) Back surface toric and bitoric GP lenses are considered easy to design and fit by most Diplomates. (2) The Mandell-Moore guide is the preferred empirical method, and the Polycon SPE is the preferred diagnostic fitting method for bitoric lenses for those responding to the survey.


Subject(s)
Astigmatism/therapy , Contact Lenses, Extended-Wear , Health Surveys , Academies and Institutes , Humans , Optometry , Prescriptions , Prosthesis Fitting , Refraction, Ocular , Treatment Outcome , United States
12.
Inorg Chem ; 44(16): 5559-61, 2005 Aug 08.
Article in English | MEDLINE | ID: mdl-16060604

ABSTRACT

A strategy to enable reactivity analogous to oxidative addition is presented for d(0) transition-metal complexes. The reaction of the redox-active ligand 2,4-di-tert-butyl-6-tert-butylamidophenolate (ap) with ZrCl(4)(THF)(2) affords the new complex Zr(IV)(ap)(2)(THF)(2). This compound is formally zirconium(IV) and contains no d electrons; however, exposure of Zr(IV)(ap)(2)(THF)(2) to chlorine gas results in swift chlorine addition at the zirconium metal center via one-electron oxidation of each ap ligand. The diradical product, Zr(IV)Cl(2)(isq)(2) (isq = 2,4-di-tert-butyl-6-tert-butyliminosemiquinone), has been characterized by X-ray crystallography, electron paramagnetic resonance spectroscopy, and SQUID magnetometery.

13.
Inorg Chem ; 44(3): 468-70, 2005 Feb 07.
Article in English | MEDLINE | ID: mdl-15679369

ABSTRACT

Addition of the dilithium salt, ortho-(Me3SiNLi)2C6H4, to ZrCl4 affords a base-free, D2d-symmetric complex Zr(IV)[ortho-(Me3SiN)2C6H4]2 (2), with rigorously planar ortho-phenylenediamine ligands. Lewis acidic 2 readily coordinates donor ligands such as NHEt2 to give the five-coordinate complex, Zr(IV)(NHEt2)[ortho-(Me3SiN)2C6H4]2 (3), which is also accessible by the reaction of Zr(NEt2)4 with 2 equiv of ortho-(Me3SiNH)2C6H4. Aryl azides react with 2 and 3 to give an unusual tetra-azametallacycle complex, 4, via 1,2-addition of a ligand N-Si bond to the organic azide. An X-ray crystal structure of 4 reveals a planar, five-membered metallacycle comprising the zirconium atom, one nitrogen atom of the ortho-(Me3SiN)2C6H4 ligand, and all three nitrogen atoms of the aryl azide.

SELECTION OF CITATIONS
SEARCH DETAIL
...