jens jensen - Academia.edu (original) (raw)
Papers by jens jensen
Australasian Conference On Interactive Entertainment, Nov 23, 2005
ABSTRACT The aim of this paper is to discuss some of the main issues associated with interactive ... more ABSTRACT The aim of this paper is to discuss some of the main issues associated with interactive genres, formats and content in the context of interactive television (ITV). First, a set of new forms or categorizations of ITV will be presented. Second, the suite of interactive genres, ...
Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 2015
The potential of different magnetron sputtering techniques for the synthesis of low friction and ... more The potential of different magnetron sputtering techniques for the synthesis of low friction and wear resistant amorphous carbon nitride (a-CN x) thin films onto temperature-sensitive AISI52100 bearing steel, but also Si(001) substrates was studied. Hence, a substrate temperature of 150 C was chosen for the film synthesis. The a-CN x films were deposited using mid-frequency magnetron sputtering (MFMS) with an MF bias voltage, high power impulse magnetron sputtering (HiPIMS) with a synchronized HiPIMS bias voltage, and direct current magnetron sputtering (DCMS) with a DC bias voltage. The films were deposited using a N 2 /Ar flow ratio of 0.16 at the total pressure of 400 mPa. The negative bias voltage, V s , was varied from 20 to 120 V in each of the three deposition modes. The microstructure of the films was characterized by high-resolution transmission electron microscopy and selected area electron diffraction, while the film morphology was investigated by scanning electron microscopy. All films possessed an amorphous microstructure, while the film morphology changed with the bias voltage. Layers grown applying the lowest substrate bias of 20 V exhibited pronounced intercolumnar porosity, independent of the sputter technique. Voids closed and dense films are formed at V s ! 60 V, V s ! 100 V, and V s ¼ 120 V for MFMS, DCMS, and HiPIMS, respectively. X-ray photoelectron spectroscopy revealed that the nitrogen-to-carbon ratio, N/C, of the films ranged between 0.2 and 0.24. Elastic recoil detection analysis showed that Ar content varied between 0 and 0.8 at. % and increased as a function of V s for all deposition techniques. All films exhibited compressive residual stress, r, which depends on the growth method; HiPIMS produces the least stressed films with values ranging between À0.4 and À1.2 GPa for all V s , while CN x films deposited by MFMS showed residual stresses up to À4.2 GPa. Nanoindentation showed a significant increase in film hardness and reduced elastic modulus with increasing V s for all techniques. The harder films were produced by MFMS with hardness as high as 25 GPa. Low friction coefficients, between 0.05 and 0.06, were recorded for all films. Furthermore, CN x films produced by MFMS and DCMS at V s ¼ 100 and 120 V presented a high wear resistance with wear coefficients of k 2.3 Â 10 À5 mm 3 /Nm. While all CN x films exhibit low friction, wear depends strongly on the structural and mechanical characteristics of the films. The MFMS mode is best suited for the production of hard CN x films, although high compressive stresses challenge the application on steel substrates. Films grown in HiPIMS mode provide adequate adhesion due to low residual stress values, at the expense of lower film hardness. Thus, a relatively wide mechanical property envelope is presented for CN x films, which is relevant for the optimization of CN x film properties intended to be applied as low friction and wear resistant coatings. V
Plant Foods for Human Nutrition, 1995
Four new high-lysine barley mutants, the variety 'Lysimax', with the high-lysine ... more Four new high-lysine barley mutants, the variety 'Lysimax', with the high-lysine gene lys3a and the mutants mother variety 'Sultan' were grown in a field trial in 1993 at Risø, Denmark. Mutants 609, 1242, 1385 and 1405 yielded in the range of 89 to 98 percent and cv 'Lysimax' yielded 102 percent of cv 'Sultan' (100 percent). One-thousand kernel weights for the mutants were in the range of 87 to 97 percent and cv 'Lysimax' 83 percent of cv 'Sultan' (100 percent). Protein contents of the mutants were slightly higher, in the range of 13.2 to 13.6 percent, than of cv 'Sultan' (13.1 percent) and 'Lysimax' which had a protein content of 12.6 percent. Fat content was higher in 'Lysimax' and in the mutants except for mutant 1385 than in cv 'Sultan' while dietary fibre contents of the barleys were similar. The levels of beta-glucans and starch were usually lower in 'Lysimax' and in the mutants. The highest lysine levels: 4.6, 4.0 and 3.7 g/16 g N occurred in cv 'Lysimax' and mutants 609 and 1405 compared to 3.3, 3.3 and 3.2 for cv 'Sultan' and mutants 1242 and 1385, respectively. Mutants 609 and 1405 and cv 'Lysimax' also had higher levels of threonine, histidine and valine. The increased lysine contents resulted in large, at most 20 percent, increases in biological value; 88.8, 81.7 and 78.3 percent for cv 'Lysimax' and mutants 609 and 1405 compared to 74.2 percent for cv 'Sultan'. True protein digestibilities and energy digestibilities were slightly lower in 'Lysimax' than in 'Sultan', 5.3 and 4.3 percentage units, respectively. It is concluded that the development of high-lysine barley varieties is very beneficial for meeting the requirements of indispensable amino acids for humans and monogastric animals. In addition, nitrogen excretion into the environment is drastically reduced due to the higher biological values of the mutants.
Magnetic Resonance Imaging, 1996
Thin Solid Films, 2014
ZrB2 thin films have been synthesized using direct current magnetron sputtering from a ZrB2 compo... more ZrB2 thin films have been synthesized using direct current magnetron sputtering from a ZrB2 compound target onto 4H-SiC(0001) and Si(100) substrates kept at different temperatures (no heating, 400 °C, and 550 °C), and substrate bias voltage (-20 V to-80 V). Time-of-flight energy elastic recoil detection analysis shows that all the films are near stoichiometric and have a low degree of contaminants, with O being the most abundant (< 1 at.%). The films are crystalline, and their crystallographic orientation changes from 0001 to a more random orientation with increased deposition temperature. X-ray diffraction pole figures and selected area electron diffraction patterns of the films deposited without heating reveal a fiber-texture growth. Four point probe measurements show typical resistivity values of the films ranging from ~95 to 200 µΩcm, decreasing with increased growth temperature and substrate bias.
Surface & Coatings Technology, 2012
A novel plasma enhanced CVD (PECVD) technique has been developed in order to combine energetic pa... more A novel plasma enhanced CVD (PECVD) technique has been developed in order to combine energetic particle bombardment and high plasma densities found in ionized PVD with the advantages from PECVD such as a high deposition rate and the capability to coat complex and porous surfaces. In this PECVD method, an ionized plasma is generated above the substrate by means of a hollow cathode discharge. The hollow cathode is known to generate a highly ionized plasma and the discharge can be sustained in direct current (DC) mode, or in high-power pulsed (HiPP) mode using short pulses of a few tens of µs. The latter option is similar to the power scheme used in high power impulse magnetron sputtering (HiPIMS), which is known to generate a high degree of ionization of the sputtered material, and thus providing new and added means for the synthesis of tailor-made thin films. In this work amorphous carbon coatings containing copper, have been deposited using both HiPP and DC operating conditions. Investigations of the bulk plasma using optical emission spectroscopy verify the presence of Ar + , C + as well as Cu + when running in pulsed mode. Deposition rates in the range 30 μm/h have been obtained and the amorphous, copper containing carbon films have a low hydrogen content of 4-5 at%. Furthermore, the results presented here suggest that a more efficient PECVD process is obtained by using a superposition of HiPP and DC mode, compared to using only DC mode at the same average input power.
Surface and Coatings Technology, 2010
The influence on thin film density using high power impulse magnetron sputtering (HiPIMS) has bee... more The influence on thin film density using high power impulse magnetron sputtering (HiPIMS) has been investigated for eight different target materials (Al, Ti, Cr, Cu, Zr, Ag, Ta, and Pt). The density values as well as deposition rates have been compared to results obtained from thin films grown by direct current magnetron sputtering (DCMS) under the same experimental conditions. Overall, it was found that the HiPIMS deposited coatings were approximately 5-15 % denser compared to the DCMS deposited coatings. This could be attributed to the increased metal ion bombardment commonly seen in HiPIMS discharges, which also was verified using a global plasma model to assess the degree of ionization of 2 sputtered metal. One key feature is that the momentum transfer between the growing film and the incoming metal ions is very efficient due to the equal mass of film and bombarding species, leading to a less pronounced columnar microstructure. As expected the deposition rates were found to be lower for HiPIMS compared to DCMS. For several materials this decrease is not as pronounced as previously reported in the literature, which is shown in the case of Ta, Pt, and Ag with rate HiPIMS /rate DCMS ~ 70-85 %, while still achieving denser coatings.
Thin Solid Films, 2012
Growth studies of sp 2-hybridized boron nitride (BN) phases by thermal chemical vapor deposition ... more Growth studies of sp 2-hybridized boron nitride (BN) phases by thermal chemical vapor deposition (CVD) are presented; of particular interest is the presence of oxygen and water during growth. While Fourier transform infrared spectroscopy reveals the presence of B-N bonds and elemental analysis by elastic recoil detection analysis shows that the films are close to stoichiometric, although containing a few atomic percent oxygen and hydrogen, Xray diffraction measurements show no indications for nucleation of any crystalline BN phases, despite change in N/B-ratio and/or process temperature. Thermodynamic modeling suggests that this is due to formation of strong B-O bonds already in the gas phase in the presence of water or oxygen during growth. This growth behavior is believed to be caused by an uncontrolled release of water and/or oxygen in the deposition chamber and highlights the sensitivity of the BN CVD process towards oxygen and water.
Surface and Coatings Technology, 2012
ABSTRACT Face centered cubic (Al0.32Cr0.68)2O3 thin films have been annealed in the temperature r... more ABSTRACT Face centered cubic (Al0.32Cr0.68)2O3 thin films have been annealed in the temperature range of 500–1000 °C during 2–8 h. The fcc structure of the film remains intact when annealed at temperatures up to 700 °C for 8 h. X-ray diffraction and transmission electron microscopy show the onset of phase transformation to corundum phase alloys in the sample annealed at 900 °C for 2 h, where annealing at 1000 °C for 2 h results in complete phase transformation to α-(Al0.32Cr0.68)2O3. In-plane and out-of-plane line scans performed in EDX TEM and θ/2θ XRD patterns did not show any phase separation into α-Cr2O3 and Al2O3 prior and after the annealing. The apparent activation energy of this process is 380–480 kJ/mol as determined by the Johnson–Mehl–Avrami model.
Scripta Materialia, 2011
Epitaxial Ti 3 SiC 2 (0001) films were deposited on 4° off-cut 4H-SiC(0001) wafers using magnetro... more Epitaxial Ti 3 SiC 2 (0001) films were deposited on 4° off-cut 4H-SiC(0001) wafers using magnetron sputtering. A lateral step-flow growth mechanism of the Ti 3 SiC 2 was discovered by X-ray diffraction, elastic recoil detection analysis, atomic force microscopy, and electron microscopy. Helium ion microscopy revealed contrast variations on the Ti 3 SiC 2 terraces, suggesting a mixed Si and Ti(C) termination. Sirich growth conditions results in Ti 3 SiC 2 layers with pronounced {11 2 0} faceting and off-oriented TiSi 2 crystallites, while stoichiometric growth yields truncated {1 1 0 0} terrace edges.
Radiology, 2006
Alzheimer disease (AD) is the most common type of dementia. It currently affects approximately 4 ... more Alzheimer disease (AD) is the most common type of dementia. It currently affects approximately 4 million people in the United States. AD is a progressive neurodegenerative disorder characterized by the gradual deposition of neuritic plaques and neurofibrillary tangles in the brain, which is thought to occur decades before the onset of clinical symptoms. Identification of people at risk before the clinical appearance of dementia has become a priority due to the potential benefits of therapeutic intervention. Although atrophy of medial temporal lobe structures has been shown to correlate with progression of AD, a growing number of recent reports have indicated that such atrophy may not be specific to AD. To improve diagnostic specificity, new quantitative magnetic resonance (MR) imaging methods are being developed that exploit known pathogenic mechanisms exclusive to AD. This article reviews the MR techniques that are currently available for the diagnostic assessment of AD.
Physical Review Letters, 1976
The importance of anisotropic two-ion couplings in the rare-earth metals, Er and Tb, as deduced f... more The importance of anisotropic two-ion couplings in the rare-earth metals, Er and Tb, as deduced from measurements of the spin-wave energies, has recently been questioned by Lindgard. I find that this objection is based on an improper expansion of the excitation energies, and that the q-dependent single-ion contributions to the spin-wave energies are unimportant within a self-consistent Hartree-Fock approximation. (AIP)
physica status solidi (RRL) - Rapid Research Letters, 2010
Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 2014
Journal of Physics D: Applied Physics, 2009
Journal of Electrocardiology, 2010
The ventricular repolarization (VR) response to short-lasting coronary occlusion has been charact... more The ventricular repolarization (VR) response to short-lasting coronary occlusion has been characterized by 3-dimensional vectorcardiography (VCG) in humans; the T vector loop becomes distorted and more circular. The purpose of this study was to relate these changes to the size of the myocardium at risk (MAR) and its location. Continuous VCG was applied during transient coronary occlusion in 35 elective angioplasty patients, and the size of the MAR was estimated by single-photon emission computed tomography. Three VR aspects were assessed at baseline vs maximum ischemia: the ST segment, the T vector angles, and the T vector loop morphology. The T loop morphology changes were significantly associated with MAR size, but also dependent of its location. In contrast, the early phase of VR reflected by the ST segment responded to acute ischemia in relation to the MAR size independent of location. The VR changes were related both to the size and the location of the MAR and most pronounced during occlusion of the left anterior descending artery.
Journal of Electrocardiology, 2010
Reliable cardiovascular (CV) risk assessment by a noninvasive tool would be of great value for CV... more Reliable cardiovascular (CV) risk assessment by a noninvasive tool would be of great value for CV event prevention. The present study consists of 187 coronary artery disease patients with 8 years of follow-up. Eight vectorcardiographic parameters characterizing different aspects of ventricular repolarization were analyzed at baseline: (1) the ST-segment (ST-VM), (2) the T vector angles (QRS-T angle, Televation, and Tazimuth), (3) the T vector loop morphology (Tavplan and Teigenvalue), and (4) Tarea and Tpeak-end. Cardiovascular death, myocardial infarction (MI), and repeated revascularization were traced via national registries. There were 16 CV deaths and 19 MIs; 89 patients remained free from CV events and revascularization. Ventricular repolarization parameters independently predicted CV death (widened QRS-T angle) and new MI (increased Tavplan) during follow-up. CV mortality was associated with increased divergence between depolarization and repolarization waves (widened QRS-T angle). Increased Tavplan, presumably reflecting heterogeneous repolarization, predicted future MI, which is a novel finding.
Australasian Conference On Interactive Entertainment, Nov 23, 2005
ABSTRACT The aim of this paper is to discuss some of the main issues associated with interactive ... more ABSTRACT The aim of this paper is to discuss some of the main issues associated with interactive genres, formats and content in the context of interactive television (ITV). First, a set of new forms or categorizations of ITV will be presented. Second, the suite of interactive genres, ...
Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 2015
The potential of different magnetron sputtering techniques for the synthesis of low friction and ... more The potential of different magnetron sputtering techniques for the synthesis of low friction and wear resistant amorphous carbon nitride (a-CN x) thin films onto temperature-sensitive AISI52100 bearing steel, but also Si(001) substrates was studied. Hence, a substrate temperature of 150 C was chosen for the film synthesis. The a-CN x films were deposited using mid-frequency magnetron sputtering (MFMS) with an MF bias voltage, high power impulse magnetron sputtering (HiPIMS) with a synchronized HiPIMS bias voltage, and direct current magnetron sputtering (DCMS) with a DC bias voltage. The films were deposited using a N 2 /Ar flow ratio of 0.16 at the total pressure of 400 mPa. The negative bias voltage, V s , was varied from 20 to 120 V in each of the three deposition modes. The microstructure of the films was characterized by high-resolution transmission electron microscopy and selected area electron diffraction, while the film morphology was investigated by scanning electron microscopy. All films possessed an amorphous microstructure, while the film morphology changed with the bias voltage. Layers grown applying the lowest substrate bias of 20 V exhibited pronounced intercolumnar porosity, independent of the sputter technique. Voids closed and dense films are formed at V s ! 60 V, V s ! 100 V, and V s ¼ 120 V for MFMS, DCMS, and HiPIMS, respectively. X-ray photoelectron spectroscopy revealed that the nitrogen-to-carbon ratio, N/C, of the films ranged between 0.2 and 0.24. Elastic recoil detection analysis showed that Ar content varied between 0 and 0.8 at. % and increased as a function of V s for all deposition techniques. All films exhibited compressive residual stress, r, which depends on the growth method; HiPIMS produces the least stressed films with values ranging between À0.4 and À1.2 GPa for all V s , while CN x films deposited by MFMS showed residual stresses up to À4.2 GPa. Nanoindentation showed a significant increase in film hardness and reduced elastic modulus with increasing V s for all techniques. The harder films were produced by MFMS with hardness as high as 25 GPa. Low friction coefficients, between 0.05 and 0.06, were recorded for all films. Furthermore, CN x films produced by MFMS and DCMS at V s ¼ 100 and 120 V presented a high wear resistance with wear coefficients of k 2.3 Â 10 À5 mm 3 /Nm. While all CN x films exhibit low friction, wear depends strongly on the structural and mechanical characteristics of the films. The MFMS mode is best suited for the production of hard CN x films, although high compressive stresses challenge the application on steel substrates. Films grown in HiPIMS mode provide adequate adhesion due to low residual stress values, at the expense of lower film hardness. Thus, a relatively wide mechanical property envelope is presented for CN x films, which is relevant for the optimization of CN x film properties intended to be applied as low friction and wear resistant coatings. V
Plant Foods for Human Nutrition, 1995
Four new high-lysine barley mutants, the variety 'Lysimax', with the high-lysine ... more Four new high-lysine barley mutants, the variety 'Lysimax', with the high-lysine gene lys3a and the mutants mother variety 'Sultan' were grown in a field trial in 1993 at Risø, Denmark. Mutants 609, 1242, 1385 and 1405 yielded in the range of 89 to 98 percent and cv 'Lysimax' yielded 102 percent of cv 'Sultan' (100 percent). One-thousand kernel weights for the mutants were in the range of 87 to 97 percent and cv 'Lysimax' 83 percent of cv 'Sultan' (100 percent). Protein contents of the mutants were slightly higher, in the range of 13.2 to 13.6 percent, than of cv 'Sultan' (13.1 percent) and 'Lysimax' which had a protein content of 12.6 percent. Fat content was higher in 'Lysimax' and in the mutants except for mutant 1385 than in cv 'Sultan' while dietary fibre contents of the barleys were similar. The levels of beta-glucans and starch were usually lower in 'Lysimax' and in the mutants. The highest lysine levels: 4.6, 4.0 and 3.7 g/16 g N occurred in cv 'Lysimax' and mutants 609 and 1405 compared to 3.3, 3.3 and 3.2 for cv 'Sultan' and mutants 1242 and 1385, respectively. Mutants 609 and 1405 and cv 'Lysimax' also had higher levels of threonine, histidine and valine. The increased lysine contents resulted in large, at most 20 percent, increases in biological value; 88.8, 81.7 and 78.3 percent for cv 'Lysimax' and mutants 609 and 1405 compared to 74.2 percent for cv 'Sultan'. True protein digestibilities and energy digestibilities were slightly lower in 'Lysimax' than in 'Sultan', 5.3 and 4.3 percentage units, respectively. It is concluded that the development of high-lysine barley varieties is very beneficial for meeting the requirements of indispensable amino acids for humans and monogastric animals. In addition, nitrogen excretion into the environment is drastically reduced due to the higher biological values of the mutants.
Magnetic Resonance Imaging, 1996
Thin Solid Films, 2014
ZrB2 thin films have been synthesized using direct current magnetron sputtering from a ZrB2 compo... more ZrB2 thin films have been synthesized using direct current magnetron sputtering from a ZrB2 compound target onto 4H-SiC(0001) and Si(100) substrates kept at different temperatures (no heating, 400 °C, and 550 °C), and substrate bias voltage (-20 V to-80 V). Time-of-flight energy elastic recoil detection analysis shows that all the films are near stoichiometric and have a low degree of contaminants, with O being the most abundant (< 1 at.%). The films are crystalline, and their crystallographic orientation changes from 0001 to a more random orientation with increased deposition temperature. X-ray diffraction pole figures and selected area electron diffraction patterns of the films deposited without heating reveal a fiber-texture growth. Four point probe measurements show typical resistivity values of the films ranging from ~95 to 200 µΩcm, decreasing with increased growth temperature and substrate bias.
Surface & Coatings Technology, 2012
A novel plasma enhanced CVD (PECVD) technique has been developed in order to combine energetic pa... more A novel plasma enhanced CVD (PECVD) technique has been developed in order to combine energetic particle bombardment and high plasma densities found in ionized PVD with the advantages from PECVD such as a high deposition rate and the capability to coat complex and porous surfaces. In this PECVD method, an ionized plasma is generated above the substrate by means of a hollow cathode discharge. The hollow cathode is known to generate a highly ionized plasma and the discharge can be sustained in direct current (DC) mode, or in high-power pulsed (HiPP) mode using short pulses of a few tens of µs. The latter option is similar to the power scheme used in high power impulse magnetron sputtering (HiPIMS), which is known to generate a high degree of ionization of the sputtered material, and thus providing new and added means for the synthesis of tailor-made thin films. In this work amorphous carbon coatings containing copper, have been deposited using both HiPP and DC operating conditions. Investigations of the bulk plasma using optical emission spectroscopy verify the presence of Ar + , C + as well as Cu + when running in pulsed mode. Deposition rates in the range 30 μm/h have been obtained and the amorphous, copper containing carbon films have a low hydrogen content of 4-5 at%. Furthermore, the results presented here suggest that a more efficient PECVD process is obtained by using a superposition of HiPP and DC mode, compared to using only DC mode at the same average input power.
Surface and Coatings Technology, 2010
The influence on thin film density using high power impulse magnetron sputtering (HiPIMS) has bee... more The influence on thin film density using high power impulse magnetron sputtering (HiPIMS) has been investigated for eight different target materials (Al, Ti, Cr, Cu, Zr, Ag, Ta, and Pt). The density values as well as deposition rates have been compared to results obtained from thin films grown by direct current magnetron sputtering (DCMS) under the same experimental conditions. Overall, it was found that the HiPIMS deposited coatings were approximately 5-15 % denser compared to the DCMS deposited coatings. This could be attributed to the increased metal ion bombardment commonly seen in HiPIMS discharges, which also was verified using a global plasma model to assess the degree of ionization of 2 sputtered metal. One key feature is that the momentum transfer between the growing film and the incoming metal ions is very efficient due to the equal mass of film and bombarding species, leading to a less pronounced columnar microstructure. As expected the deposition rates were found to be lower for HiPIMS compared to DCMS. For several materials this decrease is not as pronounced as previously reported in the literature, which is shown in the case of Ta, Pt, and Ag with rate HiPIMS /rate DCMS ~ 70-85 %, while still achieving denser coatings.
Thin Solid Films, 2012
Growth studies of sp 2-hybridized boron nitride (BN) phases by thermal chemical vapor deposition ... more Growth studies of sp 2-hybridized boron nitride (BN) phases by thermal chemical vapor deposition (CVD) are presented; of particular interest is the presence of oxygen and water during growth. While Fourier transform infrared spectroscopy reveals the presence of B-N bonds and elemental analysis by elastic recoil detection analysis shows that the films are close to stoichiometric, although containing a few atomic percent oxygen and hydrogen, Xray diffraction measurements show no indications for nucleation of any crystalline BN phases, despite change in N/B-ratio and/or process temperature. Thermodynamic modeling suggests that this is due to formation of strong B-O bonds already in the gas phase in the presence of water or oxygen during growth. This growth behavior is believed to be caused by an uncontrolled release of water and/or oxygen in the deposition chamber and highlights the sensitivity of the BN CVD process towards oxygen and water.
Surface and Coatings Technology, 2012
ABSTRACT Face centered cubic (Al0.32Cr0.68)2O3 thin films have been annealed in the temperature r... more ABSTRACT Face centered cubic (Al0.32Cr0.68)2O3 thin films have been annealed in the temperature range of 500–1000 °C during 2–8 h. The fcc structure of the film remains intact when annealed at temperatures up to 700 °C for 8 h. X-ray diffraction and transmission electron microscopy show the onset of phase transformation to corundum phase alloys in the sample annealed at 900 °C for 2 h, where annealing at 1000 °C for 2 h results in complete phase transformation to α-(Al0.32Cr0.68)2O3. In-plane and out-of-plane line scans performed in EDX TEM and θ/2θ XRD patterns did not show any phase separation into α-Cr2O3 and Al2O3 prior and after the annealing. The apparent activation energy of this process is 380–480 kJ/mol as determined by the Johnson–Mehl–Avrami model.
Scripta Materialia, 2011
Epitaxial Ti 3 SiC 2 (0001) films were deposited on 4° off-cut 4H-SiC(0001) wafers using magnetro... more Epitaxial Ti 3 SiC 2 (0001) films were deposited on 4° off-cut 4H-SiC(0001) wafers using magnetron sputtering. A lateral step-flow growth mechanism of the Ti 3 SiC 2 was discovered by X-ray diffraction, elastic recoil detection analysis, atomic force microscopy, and electron microscopy. Helium ion microscopy revealed contrast variations on the Ti 3 SiC 2 terraces, suggesting a mixed Si and Ti(C) termination. Sirich growth conditions results in Ti 3 SiC 2 layers with pronounced {11 2 0} faceting and off-oriented TiSi 2 crystallites, while stoichiometric growth yields truncated {1 1 0 0} terrace edges.
Radiology, 2006
Alzheimer disease (AD) is the most common type of dementia. It currently affects approximately 4 ... more Alzheimer disease (AD) is the most common type of dementia. It currently affects approximately 4 million people in the United States. AD is a progressive neurodegenerative disorder characterized by the gradual deposition of neuritic plaques and neurofibrillary tangles in the brain, which is thought to occur decades before the onset of clinical symptoms. Identification of people at risk before the clinical appearance of dementia has become a priority due to the potential benefits of therapeutic intervention. Although atrophy of medial temporal lobe structures has been shown to correlate with progression of AD, a growing number of recent reports have indicated that such atrophy may not be specific to AD. To improve diagnostic specificity, new quantitative magnetic resonance (MR) imaging methods are being developed that exploit known pathogenic mechanisms exclusive to AD. This article reviews the MR techniques that are currently available for the diagnostic assessment of AD.
Physical Review Letters, 1976
The importance of anisotropic two-ion couplings in the rare-earth metals, Er and Tb, as deduced f... more The importance of anisotropic two-ion couplings in the rare-earth metals, Er and Tb, as deduced from measurements of the spin-wave energies, has recently been questioned by Lindgard. I find that this objection is based on an improper expansion of the excitation energies, and that the q-dependent single-ion contributions to the spin-wave energies are unimportant within a self-consistent Hartree-Fock approximation. (AIP)
physica status solidi (RRL) - Rapid Research Letters, 2010
Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 2014
Journal of Physics D: Applied Physics, 2009
Journal of Electrocardiology, 2010
The ventricular repolarization (VR) response to short-lasting coronary occlusion has been charact... more The ventricular repolarization (VR) response to short-lasting coronary occlusion has been characterized by 3-dimensional vectorcardiography (VCG) in humans; the T vector loop becomes distorted and more circular. The purpose of this study was to relate these changes to the size of the myocardium at risk (MAR) and its location. Continuous VCG was applied during transient coronary occlusion in 35 elective angioplasty patients, and the size of the MAR was estimated by single-photon emission computed tomography. Three VR aspects were assessed at baseline vs maximum ischemia: the ST segment, the T vector angles, and the T vector loop morphology. The T loop morphology changes were significantly associated with MAR size, but also dependent of its location. In contrast, the early phase of VR reflected by the ST segment responded to acute ischemia in relation to the MAR size independent of location. The VR changes were related both to the size and the location of the MAR and most pronounced during occlusion of the left anterior descending artery.
Journal of Electrocardiology, 2010
Reliable cardiovascular (CV) risk assessment by a noninvasive tool would be of great value for CV... more Reliable cardiovascular (CV) risk assessment by a noninvasive tool would be of great value for CV event prevention. The present study consists of 187 coronary artery disease patients with 8 years of follow-up. Eight vectorcardiographic parameters characterizing different aspects of ventricular repolarization were analyzed at baseline: (1) the ST-segment (ST-VM), (2) the T vector angles (QRS-T angle, Televation, and Tazimuth), (3) the T vector loop morphology (Tavplan and Teigenvalue), and (4) Tarea and Tpeak-end. Cardiovascular death, myocardial infarction (MI), and repeated revascularization were traced via national registries. There were 16 CV deaths and 19 MIs; 89 patients remained free from CV events and revascularization. Ventricular repolarization parameters independently predicted CV death (widened QRS-T angle) and new MI (increased Tavplan) during follow-up. CV mortality was associated with increased divergence between depolarization and repolarization waves (widened QRS-T angle). Increased Tavplan, presumably reflecting heterogeneous repolarization, predicted future MI, which is a novel finding.