bluuebunny/crossref_metadata_2025_split huggingface dataset:
Erbium‐doped nanocrystalline silicon thin films produced by RF sputtering ‐ annealing effect on the Er emission
Authors: Cerqueira M. F. , Monteiro T. , Soares M. J. , Kozanecki A. , Alpuim P. , Alves E. 
Published: January 2010

AbstractIn the present work, erbium doped nanocrystalline silicon thin films were produced by reactive magnetron sputtering on glass substrates under different conditions (substrate temperature and Er content). The film structure was studied using Raman spectroscopy. The chemical composition was determined using the RBS technique. All the samples show sharp 4I13/2 → 4I15/2 intra‐4f11 emission of Er3+ related centres with its maximum positioned at the1.54 μm. However, the intensity of this transition (strongly dependent on the chemical composition of the matrix where the nanocrystals are embedded in and also on the structure of the matrix) changes after thermal annealing treatment. For the less crystalline samples our results show an increase of the Er3+ PL intensity and for the highly crystalline ones the Er emission vanishes even at low temperature. This behaviour was studied and explained in this work, on the basis of energy transfer between Si and Er ions (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Lifetime distribution of photoluminescence and radiative recombination rate of electron‐hole pairs in a‐Si:H
Authors: Ogihara Chisato , Morigaki Kazuo 
Published: January 2010

AbstractTemperature variations of radiative recombination rates of electron‐hole pairs responsible for photoluminescence in a‐Si:H films have been analysed from the intensity, I, and the characteristic value of the lifetime, τ, obtained from frequency resolved spectroscopy. In a defective a‐Si:H film, the radiative recombinationrate increases with increasing temperature because of thermal excitation of the electrons and holes from the tail states to more ex‐tended tail states. In the case of a high‐quality a‐Si:H film, the temperature variation of Iτ–1 is explained by contributions from regions in the vicinity of the defects and the regions not affected by the defects (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The annealing temperature effect on the electrical properties of boron‐doped hydrogenated amorphous silicon a‐Si:H(B)
Authors: Khelifati N. , Tata S. , Rahal A. , Cherfi R. , Fedala A. , Kechouane M. , Mohammed‐Brahim T. 
Published: January 2010

AbstractThe effects of the boron incorporation on the physico‐chemical, optical and electric properties of hydrogenated amorphous silicon (a‐Si:H) films are presented. Boron‐doped hydrogenated amorphous silicon (a‐Si:H(B)) thin films were deposited by DC magnetron sputtering where silicon and boron are co‐pulverized. They are characterized by infrared, optical absorption and electrical conductivity measurements. The boron concentration varies between 1.3 1017 cm‐3 and 1.6 1022 cm‐3. The boron incorporation induced an increase in the refractive index and a decrease in the optical gap. This incorporation is followed by a decrease of the hydrogen film content, an improvement of the electrical conductivity under darkness (σd) with a decrease of its activation energy. These results can be related to the shift of the Fermi level towards the valence band due to boron doping, but then to a significant change of structural properties. The electrical measurements under white light showed that the incorporated boron conducts to a degradation of the light sensitivity of the films. Effect of annealing temperature on electrical conductivity also shows that boron atoms passivated by hydrogen can be activated from the annealing temperature through bridging Si‐H‐‐‐B bonds dissociation (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Performance and stability of low temperature hydrogenated amorphous silicon thin film transistors fabricated on stainless steel substrate
Authors: Kim Sung Hwan , Kim Sung Ki , Lee Jong‐Kwon , Lee Seok‐Woo , Lee Hong Koo , Peak Seung Han , Park Yong‐In , Kim Chang‐Dong , Hwang Yong Kee , Chung In‐Jae 
Published: January 2010

AbstractThe key development issues in the flexible displays are TFT backplane technology, which requires competitive device performance and low temperature process compatible with flexible substrate. Here, we have fabricated low temperature hydrogenated amorphous silicon thin film transistor on a stainless steel substrate coated with organic barrier layer. Then, we have studied initial device performance by varying plasma gas and pressure conditions at a low power and a low temperature during amorphous silicon and silicon nitride deposition steps. Also, we discuss the stability characteristics of this low temperature processed thin film transistor, which reveals enough possibility for use in flexible display applications. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Aged garlic extract inhibits CD36 expression in human macrophages via modulation of the PPARγ pathway
Authors: Morihara Naoaki , Ide Nagatoshi , Weiss Norbert 
Published: January 2010

AbstractExpression of CD36 scavenger receptors on macrophages is involved in oxidized low‐density lipoprotein uptake and foam cell formation during atherosclerotic lesion development. We examined the effects of aged garlic extract (AGE), a garlic preparation enriched in water‐soluble cysteinyl moieties that increases cellular total thiols and glutathione concentrations, on CD36 expression in human monocytes/macrophages (THP‐1 cells and primary human monocytes). Compared to control, AGE (1–5 mg/mL) dose‐dependently and significantly suppressed CD36 expression up to by 61.8 ± 7.4% in THP‐1‐derived macrophages and up to 50.5 ± 7.1% in primary human macrophages, respectively. Furthermore, AGE prevented induction of CD36 expression by the peroxisome proliferator activator receptor (PPAR) γ agonist troglitazone, and decreased binding of nuclear proteins to a PPARγ response element. AGE showed a stronger inhibitory effect on CD36 expression in THP‐1 cells during simultaneous incubation with phorbol 12‐myristate 13‐acetate (PMA) compared to cells that had been pre‐incubated with PMA. Furthermore, AGE decreased CD11b expression in a dose‐dependent manner. These data indicate that AGE inhibits CD36 expression by modulating the PPARγ pathway in human macrophages and monocytes differentiation into macrophages, and suggests that the extract could be useful for the prevention of atherosclerotic lesions. Copyright © 2010 John Wiley & Sons, Ltd.
Ab initio calculations of surface electronic states in indium oxide
Authors: Fuks David , Shapiro Dina , Kiv Arnold , Golovanov Vyacheslav , Liu Chung‐Chiun 
Published: January 2010

AbstractA slab approach in the framework of ab initio calculations was applied to study surface electronic states in In2O3 crystal. Density functional theory (DFT) calculations were carried out employing the WIEN 2k code and using the full potential method with Augmented Plane Waves + local orbitals (APW+lo) formalism. Total and partial DOS (Density of States) were calculated for In and O atoms in two upper (110) surface layers. Comparison of total and partial DOS allowed determining a contribution of electronic states of different In and O surface atoms into formation of surface electronic spectra and corresponding chemical bonds. A dominant ionic character of chemical bonds in In2O3 is found. Calculations were performed for three slab models with different geometry parameters. It was shown that an optimal ratio between the whole vertical size of a supercell and the vertical size of atomic cluster has to be chosen. The size of vacuum region in the slab model influences significantly on the reliability of calculated characteristics of the surface electronic structure. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Structure and optical spectra of bis(pyrrol‐2‐ylmethyleneamine) complexes: A DFT and TDDFT study of the self‐assembly complexes of bis(pyrrol‐2‐ylmethyleneamine) ligands linked by alkyl spacers with Cu(II)
Authors: Li Wei , Yang Feng , Wang Zhengdong 
Published: January 2010

AbstractThe UV‐Vis absorption spectra of self‐assembly Cu (II) complexes for bis(pyrrol‐2‐ylmethyleneamine) linked by alkyl(CH2)n(n = 2,3,4,6) spacers were recorded. The ground‐state geometries and electronic structures were investigated by density functional theory employing generalized‐gradient approximation Perdew‐Burke‐Ernzerhof (PBE) and hybrid B3LYP (20% Ex,HF)and PBE0 (25% Ex,HF) functional, in conjugation with four basis set combinations.[BS1:6‐31G(d); BS2:Lanl2dz for Cu and 6‐31G(d) for C,H,N; BS3:6‐31+G(d); BS4:6‐311+G(d,p) for C,H,N and Lanl2dz for Cu]. Compared the optimized geometries with XRD structures, it was found that the choice of methods appeared to have a more pronounced effect on structure than that of the basis set. PBE0/BS4 optimized geometries provide the best agreement with XRD experimental results and the mean absolute errors for bond length is 0.018 Å and for bond angle is 2.1°. Transition excited states of complexes 1–4 in the gas phase and in CH2ClCH2Cl solution have been studied by the time‐dependent density functional theory in conjugated with the Polarizable Continuum Model. Pure PBE and hybrid B3LYP, PBE0 functionals, as well as BS1, BS2, and BS5 [6‐311++G (d,p)] were selected. Calculations indicate that PBE functional provides more accurate descriptions on main UV‐vis absorptions than B3LYP and PBE0 functionals. The strongest absorption bands located at 338–356 nm are due to intraligand charge transfer (ILCT) transitions, a mixed‐character ILCT + metal‐ligand charge transfer (MLCT) absorptions are calculated at 280–291 nm, the shoulder bands located at 250–257 nm mainly arise from MLCT or ligand‐metal charge transfer transitions. Alkyl spacer does not play a crucial role on the main electron transitions. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Determination of some descriptors of the real world working on the fundamental identity of the basic concept and the origin of the electronegativity and the global hardness of atoms, part 1: Evaluation of internuclear bond distance of some heteronuclear diatomics
Authors: Ghosh Dulal C. , Islam Nazmul 
Published: January 2010

AbstractIn our previous report, we have posited that there is much conceptual commonality between the two fundamental theoretical descriptors of chemistry and physics—the electronegativity and the hardness and both the fundamental descriptors originate from the same source—the electron attracting power of the screened nucleus upon the valence electrons. We have discovered the surprising result that if one measures hardness, the electronegativity is simultaneously measured and vice versa. In the present report, we have calculated the internuclear bond distances of a series of diatomic molecules invoking the ansatz for computing such bond distances in terms of the electronegativities (χ) of the atoms. We have just substituted the electronegativities (χ) by the global hardness (η) in the well established ansatz for computing bond distances of Ray et al. We have found that the computed internuclear distances are very close to the experimental bond distances. This is one validity test of our hypothesis that the electronegativity and global hardness are two different labels or legends of one and the same fundamental property of the atoms. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Kernel energy method applied to an energetic nitrate ester
Authors: Huang Lulu , Massa Lou 
Published: January 2010

AbstractA recent synthesis results in a nitrate ester explosive C6N6O16H8 (Hisk75), composed of four nitrate ester groups (ONO2) and two nitro groups (NO2), with the property of being solid at room temperature with a low‐melting point allowing the convenience of poured mold casting (Chavez et al., Angew Chem Int Ed 2008, 47, 8307). Using the crystal geometry, we have calculated the quantum chemical interaction energies, including basis set superposition errors between nearest neighboring molecules. Using quantum mechanics and the computer program CHEETA, we have calculated the explosive parameters of this new molecule, comparing to those of HMX, corroborating previous estimates of these same parameters. Calculations confirm this compound to be one of the best performing high‐energy/high‐density explosives. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Whether there is a hardness equalization principle analogous to the electronegativity equalization principle—A quest
Authors: Ghosh Dulal C. , Islam Nazmul 
Published: January 2010

AbstractIn this report, we have attempted to explore whether the hardness equalization principle can be conceived analogous to the well‐established electronegativity equalization principle. We have relied upon the fact that the hardness, like the electronegativity, is a qualitative property, and there is commonality in the basic philosophy of the origin and the operational significance of these two fundamental descriptors—the electronegativity and the hardness of atoms in physics and chemistry. Starting from the empirical radial dependent formula of computing the hardness of atoms suggested by us, we have derived an ansatz of the molecular hardness assuming that hardness equalization principle is operative and justifiably valid. For a validity test, we have applied the suggested ansatz to compute the hardness of as many as four sets of compounds with widely divergent physical and chemical nature. As hardness is not an experimentally measurable property, there is no benchmark to perform any validity test of our computed data. We have, therefore, computed the hardness data of these four different sets of the compound invoking the approximate and operational formula of Parr and Pearson, (I − A)/2, to evaluate hardness values and to compute I and A, we have invoked Koopmans' theorem and an ab initio quantum chemical method. We have observed that there is a close correlation between the four sets of hardness data computed through the semi‐empirical ansatz of this work and the quantum mechanical method. Thus, it appears that the ansatz of computing molecular hardness derived on the basis of the hardness equalization principle is efficacious in computing molecular hardness. The detailed comparative study suggests that the paradigm of the hardness equalization principle may be another law of nature like the established electronegativity equalization principle. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Modeling, experimenting, and improving skid steering on a 6 × 6 all‐terrain mobile platform
Authors: Fauroux J.‐C. , Vaslin P. 
Published: January 2010

AbstractMultiple‐wheel all‐terrain vehicles without a steering system must use great amounts of power when skid steering. Skid steering is modeled with emphasis put on the ground contact forces of the wheels according to the mass distribution of the vehicle. To increase steering efficiency, it is possible to modify the distribution of the normal contact forces on the wheels. This paper focuses on two aspects: first, it provides a model and an experimental study of skid steering on an all‐road 6 × 6 electric wheelchair, the Kokoon mobile platform. Second, it studies two configurations of the distribution of the normal forces on the six wheels, obtained via suspension adjustments. This was both modeled and experimented. Contact forces were measured with a six‐component force plate. The first results show that skid steering can be substantially improved by only minor adjustments to the suspensions. This setting decreases the required longitudinal forces applied by the engines and improves the steering ability of the vehicle or robot. Skid‐steering characteristic parameters, such as the position of the center of rotation and absorbed skid power, are also dealt with in this paper. © 2010 Wiley Periodicals, Inc.
Error minimization in the envelope method for the determination of optical constants of a thin film
Authors: Kar Meenakshi 
Published: January 2010

AbstractThe algorithm for the determination of optical constants of a weakly absorbing thin film from the envelope method has been modified to minimize the error in the estimated values of extinction coefficient (k) as a function of wavelength. The refinement procedure is based on an extension of interference order adjustment method used for improving the estimated values of film thickness d and wavelength‐dependent refractive index n from the envelope method. The proposed modification when applied to a hypothetical as well as an experimental film is found to work well over a wide spectral region. Copyright © 2010 John Wiley & Sons, Ltd.
Effect of cyanoguanidine‐metal and urea‐metal complexes on the thermal degradation of poly(vinyl chloride)
Authors: Abdel‐Naby Abir S. , Al‐Ghamdi Refaa F. , Al‐Ghamdi Azza A. 
Published: January 2010

AbstractTin, nickel, cobalt, zinc, and copper complexes of cyanoguanidine and urea were synthesized and investigated as thermal stabilizers for rigid poly(vinyl chloride) at 180°C in air. Their stabilizing efficiencies were evaluated by measuring the induction period (the period during which no evolved hydrogen chloride could be detected) and the rate of dehydrochlorination as determined by continuous potentiometric measurements, in addition to the extent of discoloration. The results clearly revealed the greater efficiency of all of the investigated metal complexes as compared to those of well‐recognized reference stabilizers. The tin complex always exhibited the highest efficiency irrespective of the type of ligand used. The nickel and cobalt complexes also possessed high stabilizing efficiencies. The order of the stabilizing potency of the various metal complexes was Sn ⋙ Co, Ni ≫ Zn, Cu. Combining the ligand itself with dimethyltin‐s,s′‐bis (isooctyl thioglycolate), as a reference stabilizer containing a tin atom, led to a true synergism. This synergistic effect might be attributed to the formation in situ of a complex between the ligand and the tin atom. J. VINYL ADDIT. TECHNOL., 2010. © 2010 Society of Plastics Engineers
Opportunistic delay‐margin‐based resource allocation for next‐generation wireless networks
Authors: Ho Quang‐Dung , Ashour Mohamed , Le‐Ngoc Tho 
Published: January 2010

AbstractThis paper studies and develops efficient traffic management techniques for downlink transmission at the base station (BS) of multi‐service IP‐based networks by combining quality‐of‐service (QoS) provision and opportunistic wireless resource allocation. A delay‐margin‐based scheduling (DMS) for downlink traffic flows based on the delays that each packet has experienced up to the BS is proposed. The instantaneous delay margin, represented by the difference between the required and instantaneous delays, quantifies how urgent the packet is, and thus it can determine the queuing priority that should be given to the packet. The proposed DMS is further integrated with the opportunistic scheduling (OPS) to develop various queueing architectures to increase the wireless channel bandwidth efficiency. Different proposed integration approaches are investigated and compared in terms of delay outage probability and wireless channel bandwidth efficiency by simulation. Copyright © 2010 John Wiley & Sons, Ltd.
Stability of a gradient elastic beam compressed by non‐conservative forces
Authors: Lazopoulos K.A. , Lazopoulos A.K. 
Published: January 2010

AbstractThe critical loads for five non‐conservative problems are defined under the context of gradient elasticity theory of a beam. The first problem deals with the stability of a gradient elastic beam compressed by a follower force (Beck's problem) and the second deals with the stability of a gradient elastic beam compressed by a force with a fixed line of action (Rent's problem). The governing dynamic equation with the boundary conditions is formulated on the bases of simple linear elasticity theory with the beam mass concentrated on the moving end. Also the case with uniform distribution of the mass along the beam will be considered. Further the effect of an additional conservative force acting on the moving end of the beam will also be discussed. Numerical applications indicate that although the surface energy term does not have a substantial effect, the intrinsic length due to gradient elasticity is of major importance. In fact, it increases of the critical load.
Pain and clinical findings in the low back: A study of industrial employees with 5‐, 10‐, and 28‐year follow‐ups
Authors: Kääriä Sanna‐Mari , Mälkiä Esko A. , Luukkonen Ritva A. , Leino‐Arjas Päivi I. 
Published: January 2010

AbstractLittle is known about the relationships of clinical findings in the low back with low back pain (LBP) in the normal working population. We studied whether physiotherapist's findings in the low back were associated with local and radiating LBP among a cohort (n = 902) of employees in the engineering industry. A systematic non‐proportional sample was drawn in strata by age, gender, and occupational class. The non‐proportionality aimed at increasing sample size in smaller strata. Physiotherapists performed the straight‐leg raising test (SRL), and made assessments of the fingertip‐to‐floor distance and pain in palpation of the lumbar interspinous spaces. The variables on pain at the interspinous spaces and the SRL tests were entered in cluster analysis. Three clusters emerged: no, minor, and severe clinical findings. In logistic regression analysis at baseline, limited forward flexion and the clinical findings cluster variable were associated with local and, particularly, radiating LBP. Follow‐ups of the occurrence of local and radiating LBP at 5, 10, and 28 years from baseline were made. At the 5‐year follow‐up among subjects with no radiating LBP at baseline, the OR of radiating LBP for the clusters of minor and severe clinical findings compared to no findings were 2.7 (95% CI 1.4–5.1) and 3.8 (2.0–6.9), respectively, adjusted for age, gender, and occupational class. At the 10‐year follow‐up, the latter cluster predicted new reports of radiating LBP (1.9; 1.0–3.1) and of local LBP (4.1; 1.9–9.0, among subjects with no local LBP at baseline), similarly adjusted. No associations between limited forward flexion and new cases of LBP were observed. Thus, membership in clusters with different levels of findings in simple clinical measurements predicted new reports of radiating LBP, in particular, among employees. The generalizability of the results may be limited due to the characteristics of the sampling.