41 results on '"R H Yu"'
Search Results
2. [The thromboembolism risk of low-risk atrial fibrillation patients with different clinical characteristics]
- Author
-
X B, Liu, Z X, Jia, S J, Xia, L, He, S X, Lu, X Y, Guo, S N, Li, N, Liu, C X, Jiang, C H, Sang, R B, Tang, D Y, Long, R H, Yu, R, Bai, J H, Wu, X, Du, J Z, Dong, and C S, Ma
- Subjects
Adult ,Male ,Stroke ,China ,Risk Factors ,Thromboembolism ,Atrial Fibrillation ,Anticoagulants ,Humans ,Female ,Middle Aged ,Risk Assessment ,Aged - Published
- 2020
3. [Transseptal puncture: anatomy, instruments and methods]
- Author
-
R H, Yu, Q, Qiao, and J, Li
- Subjects
Cardiac Catheterization ,Catheter Ablation ,Heart Septum ,Punctures - Abstract
房间隔穿刺术是介入心脏病学最常用的技术之一,近年来随着三维电学的发展,临床上对房间隔穿刺术有了新的认识。解剖方面,卵圆窝电位的发现体现了电学方法对解剖学的重建,有助于将“房间隔识别并穿刺”转化为“卵圆窝识别并穿刺”。器械方面,新近出现的射频针和穿刺导丝可以易化穿刺过程。方法学上,三维电解剖标测方法和X线方法相比,前者呈现三维化视角,通过电位标测能够精确定位卵圆窝,提升了穿刺成功率;后者不需配备电解剖标测系统,不需要预先标测,操作较为简洁。三维电解剖标测方法和超声方法相比,前者能够标测卵圆窝最中心位置,定位精准,同时也能实时追踪穿刺针尖;后者解剖层次清晰,但只能展现二维界面,由于需要增加超声设备,花费也较多。虽然大多数情况下X线指导的房间隔穿刺术是安全有效的,而超声的辅助定位作用能够提高安全性,但新近出现的三维电解剖标测技术是更适用的无射线房间隔穿刺方法。.
- Published
- 2020
4. Lipoxin A4 alleviates lung injury in sepsis rats through p38/MAPK signaling pathway
- Author
-
X H, Hu, H L, Situ, J P, Chen, and R H, Yu
- Subjects
Lipoxins ,Rats, Sprague-Dawley ,Sepsis ,Animals ,Lung ,Rats ,Signal Transduction - Abstract
The aim of the study was to explore the effect of lipoxin A4 (LXA4) on lung injury in sepsis rats through the p38/mitogen-activated protein kinase (MAPK) signaling pathway. Sprague-Dawley rats were used for the study. The rat model of sepsis-induced acute lung injury was established via cecal ligation (Sepsis group, n=20). LXA4 (0.1 mg/kg) was injected at 6 h after modeling (Treatment group, n=20), and a The Control group (n=20) was also set up. The 7-day survival rate was 100% in The Control group, and LXA4 raised the survival rate of rats in the Sepsis group from 40% to 60% (P0.01). Alveolar fluid clearance (AFC) significantly declined and the wet/dry weight (W/D) ratio of lung tissues rose remarkably in the Sepsis group compared with those in the Control group, while LXA4 restored AFC and reduced the W/D ratio of lung tissues (P0.05), suggesting that LXA4 treatment reduces lung fluids and partially enhances AFC, thus lowering the W/D ratio of lung. The total cell count, polymorphonuclear neutrophils (PMN) percentage and concentration of tumor necrosis factor-α (TNF-α) and interleukin (IL)-6 in bronchoalveolar lavage fluid (BALF) were obviously increased in the Sepsis group compared with those in the Control group, while they were markedly decreased in the Treatment group (P0.05). The activity of myeloperoxidase (MPO) in lung tissue homogenate was evidently higher in the Sepsis group than that in The Control group, while it was notably lower in the Treatment group than that in the Sepsis group after LXA4 treatment (P0.05). Moreover, it was observed microscopically that the morphology of lung tissues was intact in the Control group. Finally, the results of Western blotting manifested that the p-p38/ MAPK protein expression was remarkably increased in the Sepsis group, indicating the activation of the p38/MAPK pathway, while it was remarkably decreased in the Treatment group, indicating the inhibited activity of the pathway (P0.05). LXA4 has an anti-inflammatory effect on sepsis rats with lung injury, and such effect is related to the p38/MAPK signaling pathway.
- Published
- 2020
5. MiR-135a inhibitor alleviates pulmonary arterial hypertension through β-Catenin/GSK-3β signaling pathway
- Author
-
R-H, Yu, L-M, Wang, and X-H, Hu
- Subjects
Rats, Sprague-Dawley ,Disease Models, Animal ,MicroRNAs ,Pulmonary Arterial Hypertension ,Glycogen Synthase Kinase 3 beta ,Monocrotaline ,Animals ,Injections, Intraperitoneal ,beta Catenin ,Rats ,Signal Transduction - Abstract
The aim of this study was to investigate the regulatory role of micro-ribonucleic acid (miR)-135a in monocrotaline (MCT)-induced pulmonary arterial hypertension (PAH) in rats, and to analyze the possible regulatory mechanism.A total of 30 Sprague-Dawley rats were randomly divided into three groups, including the blank control group, model group and miR-135a inhibitor intervention group. The right ventricular systolic pressure (RVSP) and right ventricle hypertrophy index (RVHI) were measured in rats of each group. Hematoxylin and eosin (HE) staining was adopted to detect the pathological changes in lung tissues of rats. Enzyme-linked immunosorbent assay (ELISA) was performed to measure the levels of interleukin-6 (IL-6) and IL-1β in lung tissues. Meanwhile, the messenger RNA (mRNA) and protein levels of β-catenin and glycogen synthase kinase-3β (GSK-3β) in lung tissues of rats were determined via Reverse Transcription-Polymerase Chain Reaction (RT-PCR) and Western blotting assay, respectively.Compared with the blank control group, RVSP and RVHI increased significantly in the model group. The pathological morphology of the lung tissues was poor, and the content of IL-6 and IL-1β was markedly up-regulated in the model group. Meanwhile, the mRNA and protein levels of β-catenin and GSK-3β were notably elevated in the model group than the blank control group. In the miR-135a inhibitor intervention group, RVSP and RVHI decreased significantly, and the pathological morphology of lung tissues was evidently improved when compared with the blank control group. Furthermore, the content of IL-6 and IL-1β was remarkably reduced, and the mRNA and protein levels of β-catenin and GSK-3β were significantly declined in the miR-135a inhibitor intervention group.MiR-135a inhibitor significantly alleviates inflammatory response in the lung tissues and ameliorates damage to the pathological morphology. The possible underlying mechanism may be associated with the β-catenin/GSK-3β signaling pathway.
- Published
- 2019
6. Mechanical and magnetic characterisation of Al2O3 reinforced Fe–Co alloy composites
- Author
-
J. Zhu, R. H. Yu, L. N. Huang, and X. B. Ma
- Subjects
Diffraction ,Materials science ,Mechanical Engineering ,Metallurgy ,Alloy ,Nanoparticle ,engineering.material ,Condensed Matter Physics ,Magnetization ,Mechanics of Materials ,Ultimate tensile strength ,Vickers hardness test ,engineering ,Curie temperature ,General Materials Science ,Composite material ,Saturation (magnetic) - Abstract
Fe–Co based alloys were strengthened through Al2O3 homogenous dispersion within the matrix, using mechanical alloying method (MA). The structure and properties of alloys were investigated by X-ray diffraction (XRD), field emission scanning electron microscopy, Vickers hardness, tensile, compression and soft magnetic test. By Al2O3 nanoparticle reinforcing, the Fe–Co alloys have shown outstanding mechanical properties besides the high saturation magnetisation and high curie temperature, which can benefit their industrial application.
- Published
- 2015
7. Microstructure and electrical properties of praseodymium oxide doped Bi2O3based ZnO varistor films
- Author
-
Hongming Yuan, K. He, R. H. Yu, Y. T. Yang, H. X. Xu, Y. Tong, J. P. Qi, D. Xu, J. Ma, and Xiujuan Sun
- Subjects
Materials science ,Praseodymium ,Mechanical Engineering ,Doping ,Oxide ,chemistry.chemical_element ,Varistor ,Dielectric ,Condensed Matter Physics ,Microstructure ,chemistry.chemical_compound ,chemistry ,Mechanics of Materials ,Electronic engineering ,General Materials Science ,Dielectric loss ,Thin film ,Composite material - Abstract
Pr2O3 and Pr6O11 doped ZnO thin films were prepared by the sol–gel method respectively. The microstructure and electrical characteristics of the samples were investigated by X-ray diffraction (XRD), atomic force microscopy (AFM), varistor dc parameter analyser and impedance analyser. Two kinds of Pr-oxide doped ZnO thin film with similar phase which contain well crystallised ZnO. The grains of Pr2O3 doped ZnO thin films and Pr6O11 doped ZnO thin films are uniform and closely packed, and all samples have lower surface roughness. When the doping content of Pr2O3 is 0·90 mol.-%, the varistor properties of ZnO thin film are optimum, the leakage current is 487 μA, the potential gradient is 232 V mm−1 and the nonlinear coefficient is 2·5. The dielectric constant of ZnO thin films increases in a certain degree with different contents of Pr2O3 and Pr6O11 doping. The Pr2O3 doping reduces the dielectric loss effectively, but the Pr6O11 doping has the opposite effect. These results provide favourable theoret...
- Published
- 2014
8. Effect of Al2O3 doping on electric and dielectric properties of ZnO linear resistor
- Author
-
J. P. Qi, Y. Luo, K. He, R. H. Yu, D. Xu, J. Xie, and Hongming Yuan
- Subjects
Range (particle radiation) ,Materials science ,Condensed Matter::Other ,Mechanical Engineering ,Doping ,chemistry.chemical_element ,Sintering ,Zinc ,Dielectric ,Condensed Matter Physics ,Microstructure ,Computer Science::Other ,law.invention ,Condensed Matter::Materials Science ,chemistry ,Mechanics of Materials ,law ,Condensed Matter::Superconductivity ,General Materials Science ,Resistor ,Composite material ,Ball mill - Abstract
Al doped ZnO linear resistors were prepared by the high energy ball milling. The effects of content of Al2O3 on the electrical properties of the linear resistors were investigated. Al doped ZnO reduces the non-linear coefficient to some extent at the sintering temperature of 1350°C. When the content of Al2O3 was 3·5 mol-%, the best performance of linear resistor of the non-linear coefficient 1·0 was obtained. The dielectric constant of ZnO linear resistors was the most stable over the frequency range of 1 00 000–10 000 000 Hz when the content of Al2O3 was 4·5 mol-%.
- Published
- 2014
9. Preparation and magnetic properties of novel hybrid magnetic powder cores
- Author
-
Y. Cao, R. H. Yu, B. Yang, and Liqun Zhang
- Subjects
Materials science ,Magnetic composite ,Silicon ,Mechanical Engineering ,Metallurgy ,Mixing (process engineering) ,chemistry.chemical_element ,Core (manufacturing) ,Condensed Matter Physics ,Magnetic powder ,Electromagnetic induction ,Iron powder ,chemistry ,Mechanics of Materials ,General Materials Science ,Composite material - Abstract
Magnetic powder cores are an important kind of soft magnetic materials that are widely used in various electrical and magnetic devices. In this work, high performance hybrid magnetic powder cores have been prepared by compacting silicon resin coated soft magnetic composite (SMC) powders. The SMC powders are obtained from mixing suitable proportions of FeSi and FeNi powders uniformly with pure iron powders. A high density of over 7·27 g cm−3 can be obtained in hybrid magnetic powder cores. The core loss of the magnetic cores prepared from mixing 90 wt-%Fe and 10 wt-%FeSi powders measured at a frequency of 50 Hz and an induction level of 1 T is 7·5 W kg−1, which is much lower than that of pure iron powder cores (8·4 W kg−1), and their magnetic induction measured at an induction level of 10 kA m−1 is 1·38 T, which is higher than that of pure iron powder cores (1·34 T).
- Published
- 2014
10. [Role of hypoxia-inducible factor in the pathogenesis of rheumatoid arthritis]
- Author
-
R H, Yu, J X, Zhao, and X Y, Liu
- Subjects
Inflammation ,Neovascularization, Pathologic ,Aryl Hydrocarbon Receptor Nuclear Translocator ,Synovial Membrane ,Apoptosis ,Arthritis, Rheumatoid ,Repressor Proteins ,Cartilage ,Cell Movement ,Basic Helix-Loop-Helix Transcription Factors ,Humans ,Hypoxia-Inducible Factor 1 ,Apoptosis Regulatory Proteins ,Hypoxia - Abstract
Rheumatoid arthritis (RA) is a destructive chronic autoimmune disease characterized by synovium inflammation, cartilage destruction, bone erosion and the presence of autoantibodies. Hypoxia is a prominent micro-environmental feature in a range of disorders including RA. A combination of increased oxygen consumptionby inflamed resident cells and infiltrating immune cells along with a disrupted blood supply due to vascular dysfunction contribute to tissue hypoxia in RA. Hypoxia in turn regulates a number of key signaling pathways that help adaptation. The primary signaling pathway activated by hypoxia is the hypoxia-inducible factor (HIF) pathway. It has been shown that HIFs are highly expressed in the synovium of RA. HIFs mediate the pathogenesis of RA through inducing inflammation, angiogenesis, cell migration, and cartilage destruction, and inhibiting the apoptosis of synovial cells and inflammatory cells. HIF expressed in RA can be regulated in both oxygen-dependent and independent fashions, like inflammatory cytokines, leading to the aggravation of this disease. Considering the vital role of HIF in the pathogenesis of RA, we reviewed the new advances about hypoxia and RA. In this review, we firstly discussed the hypoxia-inducible factor and its regulation, and then, the pathologic role of hypoxia in RA, mainly elucidating the role of hypoxia in synovitis and cartilage destruction and immune cells. Finally, we provided evidence about the potential therapeutic target for treating RA.
- Published
- 2016
11. Role of hydroxyl (OH) on structural and ferrimagnetism of annealed CoFe2O4nanoparticles
- Author
-
P L Niu, R H Yu, Haibo Zeng, and P Wang
- Subjects
Materials science ,Magnetic moment ,Condensed matter physics ,Annealing (metallurgy) ,Mechanical Engineering ,Spinel ,chemistry.chemical_element ,engineering.material ,Coercivity ,Condensed Matter Physics ,Magnetization ,Nuclear magnetic resonance ,chemistry ,Nanocrystal ,Mechanics of Materials ,Ferrimagnetism ,engineering ,General Materials Science ,Cobalt - Abstract
Cobalt ferrites (CoFe2O4) with high magnetic moments and coercivity are proposed for the fabrication of media recording devices; however, their very high coercivity, which produces noise, is big hurdle in the practical form of these devices. Cobalt ferrites with high magnetic moment and moderate coercivity, and the role of hydroxyls on the structural and ferrimagnetic properties, have been investigated in detail. The proposed research investigates the following aspects that are important in understanding the role of hydroxyls: (1) the average particle size and presence of hydroxyls are correlated to the annealing temperatures, and (2) the hydroxyls have considerably influenced the structure and magnetic ordering in the nanocrystal. The prepared single spinel structure of cobalt ferrites exhibits good saturated hysteresis loops with ferrimagnetic behaviour and annealing at high temperature observed to play a significant role for the tuning of particle size, saturation magnetisation, coercivity and ...
- Published
- 2013
12. Analysis of genetic distance by SSR in waxy maize
- Author
-
Yingxian Sun, R H Yu, Y L Wang, and B Liu
- Subjects
Genetic Markers ,Genetics ,Genetic diversity ,DNA, Plant ,Heterosis ,Genetic Variation ,General Medicine ,Biology ,Zea mays ,chemistry.chemical_compound ,Phenotype ,chemistry ,Genetic distance ,Inbred strain ,Genetic marker ,Molecular marker ,Genetic variation ,Hybrid Vigor ,Inbreeding ,Molecular Biology ,Microsatellite Repeats - Abstract
We examined the genetic diversity of 80 inbred waxy maize lines using 22 SSR molecular markers that could be used to achieve heterosis in waxy maize. Eighty inbred waxy maize lines with different phenotypes, 40 yellow, 25 white, 13 black, and two red lines were analyzed by SSR molecular marker fingerprint and cluster analysis. Using a standard genetic distance of 0.55, the 80 waxy maize inbred lines were clustered into nine groups. Among them, group II, group V, groups VII and VIII, and group IX were divided into three subgroups at a genetic distance of 0.46, into two subgroups at 0.49, into two subgroups at 0.46, and into four subgroups at 0.493, respectively. All but one of the yellow waxy maize inbred lines were clustered in groups VI, VII, VIII, and IX. Group IX (30 lines) contained 28 yellow lines; the other 11 yellow lines were distributed among groups VI, VII and VIII. Among the 25 white lines, 21 were clustered in groups III, V, VI and the third subgroup of group II. The black line N72 was in a group of its own. The black lines N75, N76 and N78 were distributed in groups VII, VIII and IX, respectively. The other nine black lines were clustered in group II. The red lines were distributed in the second subgroup of group II and there was no difference in genetic distance between them. In conclusion, there were considerable genetic differences among waxy maize inbred lines of different colors. The mean genetic distance of inbred lines of the same color was significantly less than that of lines of different colors. Therefore, we concluded that it was more accurate to determine the difference between the populations using the highly stable DNA genetic markers.
- Published
- 2012
13. Scaling law of anomalous Hall effect in Fe/Cu bilayers
- Author
-
W. J. Xu, B. Zhang, Z. Wang, S. S. Chu, W. Li, Z. B. Wu, R. H. Yu, and X. X. Zhang
- Subjects
Scaling law ,Materials science ,Condensed matter physics ,Electrical resistivity and conductivity ,Scattering ,Hall effect ,Skew ,Condensed Matter Physics ,Scaling ,Electron scattering ,Electronic, Optical and Magnetic Materials - Abstract
The scaling of anomalous Hall resistivity on the longitudinal resistivity has been intensively studied in the different magnetic systems, including multilayers and granular films, to examine which mechanism, skew scattering or side-jump, dominates. The basis of the scaling law is that both the resistivities are due to the electron scattering at the imperfections in the materials. By studying of anomalous Hall effect (AHE) in the simple Fe/Cu bilayers, we demonstrate that the measured anomalous Hall effect should not follow the scaling laws derived from skew scattering or side-jump mechanism due to the short-circuit and shunting effects of the non-magnetic layers.
- Published
- 2008
14. An interactive visual simulation framework for radar network detection coverage in a complicated environment
- Author
-
L. D. Wu, C. Yang, and R. H. Yu
- Subjects
business.industry ,Computer science ,Real-time computing ,Computer vision ,Artificial intelligence ,Radar network ,business - Published
- 2015
15. High temperature soft magnetic materials: FeCo alloys and composites
- Author
-
Yong Zhang, L. Ren, John Q. Xiao, R. H. Yu, A. Parvizi-Majidi, S. Basu, and K.M. Unruh
- Subjects
Magnetic anisotropy ,Materials science ,Ferromagnetism ,Magnetic shape-memory alloy ,Creep ,Precipitation (chemistry) ,Vickers hardness test ,Electrical and Electronic Engineering ,Composite material ,Coercivity ,Grain size ,Electronic, Optical and Magnetic Materials - Abstract
We have systematically investigated the microstructural effects including grain size, precipitation, and structural order parameter on the high temperature magnetic and mechanical properties of FeCo-based commercial alloys. At high temperatures the equilibrium nonmagnetic precipitates significantly deteriorate the soft magnetic properties. Poor mechanical properties are mainly due to the nature of the ordered structure of FeCo alloys. Based on this understanding we have designed new magnetic composites by reinforcing FeCo alloys with high strength fibers. The magnetic and mechanical properties can thus be improved independently through optimizing the magnetic matrix and fiber network, respectively. These new magnetic composites show excellent soft magnetic and mechanical properties. In particularly, negligible creep has been observed at 600/spl deg/C.
- Published
- 2000
16. Pinning effect of the grain boundaries on magnetic domain wall in FeCo-based magnetic alloys
- Author
-
Azar Parvizi-Majidi, R. H. Yu, John Q. Xiao, S. Basu, and Yong Zhang
- Subjects
Grain growth ,Materials science ,Magnetic domain ,Ferromagnetism ,Zener pinning ,Condensed matter physics ,General Physics and Astronomy ,Grain boundary ,Coercivity ,Grain size ,Grain boundary strengthening - Abstract
We have studied the dynamics of grain growth and the pinning effect of grain boundaries on magnetic domain walls in FeCo soft magnetic alloys. It has been found that grain growth takes place at temperatures above 600 °C. The activation energy for grain growth in a disordered state at 820 °C is about 57.4±0.5 kcal/mole. The effect of grain size on magnetic properties has been singled out by keeping the same ordering parameter (S=0 and 0.88) for all samples studied. Microstructural characterization and magnetic measurements indicate that the grain size significantly affects the magnetic coercivity. A linear relationship between the coercivity and the reciprocal of the grain size has been universally found regardless of the heat-treatment histories. Lorenz microscopic observation demonstrates that grain boundaries act as pinning sites for the magnetic domain wall movement.
- Published
- 1999
17. Temperature dependence of the magnetic and transport properties of Co15Cu85 magnetic granular alloys
- Author
-
R. H. Yu, J. Zhu, X. X. Zhang, and Javier Tejada
- Subjects
Condensed Matter::Materials Science ,Materials science ,Magnetic shape-memory alloy ,Magnetoresistance ,Condensed matter physics ,Electrical resistivity and conductivity ,General Physics and Astronomy ,Magnetic nanoparticles ,Giant magnetoresistance ,Electron ,Granular material - Abstract
The temperature dependence of magnetic and transport properties of annealed Co15Cu85 alloys has been studied from 2 to 300 K. It was found that the magnetic property and resistivity significantly change with the temperature. Based on the two-current resistance model, we have calculated the electron spin-mixing parameter Q(T), which explains the magnetoresistance change with the temperature for granular Co15Cu85 alloys.
- Published
- 1998
18. Mediating distribution of magnetic Co ions by surfactant in Co-doped SnO2 nanorods
- Author
-
H, Jiang, X F, Liu, Z Y, Zou, R H, Tang, W, Liu, and R H, Yu
- Abstract
We demonstrate a method to control the distribution of magnetic Co ions in Co-doped SnO2 nanorods by the surfactant. The nanorods with nanoflower morphology have been synthesized by surfactant-assisted hydrothermal method. The X-ray absorption fine structure spectra at Co K-edge reveal that Co ions substitute for Sn site in SnO2 lattice. The X-ray absorption fine structure spectra at O K-edge with its simulated spectra have been performed to investigate the local environment of Co ions. In the experimental spectra, the pre-edge peak continues to decline with the addition of the surfactant. It shows the same trend when the number of clustered Co ions in the simulated spectra is reduced, which indicates that the surfactant suppresses the formation of Co clusters. The effect of surfactant in mediating Co distribution arises from the strong interactions between the Co2+ ions and the CTA+ ions. In the Co K-edge experimental spectra, the weakened pre-edge peak reflects the electron transfer from the CTA+ ions to Co 3d band. Such electron transfer changes the charge state of Co ions and modifies the electrostatic interactions among dopant ions, leading to the uniform distribution of substitutional Co dopants. These results provide experimental guidance in the synthesis of the homogeneous-doped metal oxide semiconductors.
- Published
- 2013
19. Cobalt rich phase formation in metastable Cu–Co alloys by means of melt spinning
- Author
-
Marcelo Knobel, R. H. Yu, X. X. Zhang, and J. Zhu
- Subjects
Materials science ,Mechanical Engineering ,Nucleation ,chemistry.chemical_element ,Condensed Matter Physics ,Copper ,Crystallography ,chemistry ,Chemical engineering ,Mechanics of Materials ,Phase (matter) ,Volume fraction ,General Materials Science ,Particle size ,Melt spinning ,Solubility ,Cobalt - Abstract
Metastable COxCU100−x alloys with extended cobalt solubility (5≤x≤20), which can not be obtained by equilibrium methods, were prepared by melt spinning. The separation of the cobalt rich phase upon heating was monitored by X-ray diffraction and calorimetric measurements. The volume fraction of cobalt rich particles can not be determined using X-ray diffraction if the cobalt rich particle size is below a critical value. The separation of the cobalt rich phase seems to be a three step process including nucleation, growth, and coarsening. The non-isothermal kinetics of nucleation and growth of the cobalt rich phase were analysed in terms of a modified Kissinger model. The heat release during phase separation is closely related to the amount of cobalt dissolved in the copper matrix.MST/3258
- Published
- 1996
20. The magnetic behaviour in heterogeneous f.c.c. Co10Cu90melt-spun ribbons
- Author
-
X. X. Zhang, R. H. Yu, M. Knobel, and G. Sardin
- Subjects
Materials science ,Magnetometer ,Annealing (metallurgy) ,Metallurgy ,Alloy ,Coercivity ,engineering.material ,Condensed Matter Physics ,law.invention ,law ,Metastability ,engineering ,Magnetic alloy ,Composite material ,Joule heating ,Superparamagnetism - Abstract
The metastable magnetic alloy Co10Cu90 has been prepared by the conventional melt-spinning technique. The rapid solidification process results in an extended solubility of Co in Cu although some Co particles already have precipitated during quenching. In comparison with conventional ageing methods, Joule heating could also be adopted to fabricate granular Co-Cu alloys with even finer Co particles. The finest size of 4.0nm has been achieved for Co10Cu90 alloy after annealing with a current I = 4 A for 1 rnin. Single-domain behaviour results in a value of coercivity in excess of 40.0 kAm−1 for the sample annealed with I = 9.5 A. Below the size of 6.0 nm, Co particles exhibit superparamagnetic behaviour at room temperature, which has been investigated using a superconducting quantum interference device magnetometer. A unique change in M s with annealing current or temperature was discovered.
- Published
- 1995
21. Magnetic properties of (Nd,Pr,Dy)2Fe14B/α-Fe nanocomposite magnets crystallized in a magnetic field
- Author
-
B. Z. Cui, M. Q. Huang, R. H. Yu, A. Kramp, J. Dent, D. D. Miles, and S. Liu
- Subjects
Materials science ,Condensed matter physics ,Magnetic energy ,Magnetic domain ,General Physics and Astronomy ,Coercivity ,Magnetic susceptibility ,Condensed Matter::Materials Science ,Paramagnetism ,Magnetic anisotropy ,Nuclear magnetic resonance ,Magnetic shape-memory alloy ,Remanence ,Condensed Matter::Superconductivity - Abstract
The effect of applying a magnetic field during the crystallization process of a melt-spun Nd2.4Pr5.6Dy1Fe85B6 alloy on the nanostructure, crystallographic texture, exchange coupling, and magnetic properties has been studied. Compared with samples annealed without magnetic field, there was a noticeable improvement in the intrinsic coercivity iHc, the remanence Br, and the maximum magnetic energy product (BH)max for Nd2.4Pr5.6Dy1Fe85B6 alloys annealed in a 12 kOe field. The magnetic performance improved with an increase in the magnetic fields applied up to 9 kOe. Crystallographic alignment and magnetically anisotropic behavior were found in the samples crystallized in the magnetic field. The improvement in magnetic properties after magnetic crystallization is considered to be the result of both magnetic-field-induced crystallite alignment and enhanced exchange coupling due to a reduction of grain size.
- Published
- 2003
22. [Untitled]
- Author
-
R. H. Yu, Xinde Bai, Q. G. Zhou, X. W. Chen, and D. Q. Peng
- Subjects
chemistry.chemical_classification ,Aqueous solution ,Materials science ,Aqueous corrosion ,Metallurgy ,Zirconium alloy ,chemistry.chemical_element ,Sulfuric acid ,Polymer ,Corrosion ,Cerium ,chemistry.chemical_compound ,Ion implantation ,chemistry ,General Materials Science ,Nuclear chemistry - Published
- 2002
23. First‐principles calculations of electronic subband structure and elementary excitations of a quantum wire
- Author
-
R. H. Yu
- Subjects
Physics ,Condensed matter physics ,Quantum wire ,Fermi level ,Surfaces and Interfaces ,Electronic structure ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Condensed Matter Physics ,Surfaces, Coatings and Films ,symbols.namesake ,Quantum mechanics ,Dispersion relation ,Quasiparticle ,symbols ,Fermi gas ,Wave function ,Harmonic oscillator - Abstract
Self‐consistent calculations of the subband electronic structure of semiconductor quantum wires are reported. The Schrodinger and Poisson equations were solved simultaneously in a rectangular waveguide geometry, using Fermi statistics for electrons at finite temperature. Calculated energy levels, wave functions, charge density, and potential differ from the predictions of the simple square well and harmonic oscillator models because of the influence of accumulation and depletion regions. The subband energies depend on the free‐carrier density and the temperature as well as the band bending. Based on the self‐consistently determined subband structure, the dynamical structure factor was evaluated using a nonlocal description of dielectric response theory in the random‐phase approximation at finite temperature. We obtain intersubband as well as intrasubband plasmons and discuss their dispersion relations, localization, and line shapes. The dynamical structure factor of our model quasi‐one‐dimensional electro...
- Published
- 1992
24. Novel soft magnetic composites fabricated by electrodeposition
- Author
-
John Q. Xiao, S. Basu, Libo Ren, Azar Parvizi-Majidi, R. H. Yu, and Karl Unruh
- Subjects
Magnetic measurements ,Materials science ,Ferromagnetism ,Annealing (metallurgy) ,Magnet ,Metallurgy ,Vickers hardness test ,Volume fraction ,Mechanical strength ,Iron alloys ,General Physics and Astronomy ,Composite material - Abstract
Soft magnetic composites have been fabricated by electrodepositing FeNi and FeCo onto W fibers with a diameter of 20 and 100 μm. Structural and compositional characterizations indicate that FeNi and FeCo-based composites are of fcc and bcc structure, respectively. The mechanical strengths are significantly improved depending on the volume fraction of W fibers. To further improve the mechanical properties of these composites, we have codeposited soft magnets and Al2O3 powders, resulting in an increase in Vickers hardness of more than 100%. Magnetic measurements show that as-deposited fibers are not magnetically soft. After proper thermal annealing, the samples exhibit excellent soft magnetic properties.
- Published
- 2000
25. Memory effect in standard spin valve structures
- Author
-
Y. F. Li, D. V. Dimitrov, John Q. Xiao, and R. H. Yu
- Subjects
Magnetization ,Exchange bias ,Domain wall (magnetism) ,Materials science ,Condensed matter physics ,Ferromagnetism ,Magnetoresistance ,Spin valve ,General Physics and Astronomy ,Antiferromagnetism ,Spin-½ - Abstract
Memory effect has been observed in both standard top and bottom spin valves. The change of the magnetization state in the pinned FM layer, below the blocking temperature, reverses the direction of the exchange bias and destroys the magnetoresistance properties. This reversed exchange bias is much weaker, causing severe consequences in SV applications. This behavior can be explained in terms of blocking temperature distribution in the AFM layer perhaps due to the structural randomness. By varying cooling procedures, the exchange coupling in regions with different blocking temperatures can be separated. It is found that the maximum exchange bias is very close to the sum of the exchange biases in different regions. The domain wall energy in the FM layer has to be taken into account in order to explain the behavior of the reversed bias. The insertion of a synthetic antiferromagnetic subsystem (Co/Ru/Co) stabilizes the magnetization state in the pinned layer because of the additional interlayer coupling through the Ru layer. This suppresses the memory effect.
- Published
- 2000
26. Magneto-impedance effect in soft magnetic tubes
- Author
-
R. H. Yu, S. Basu, G. Landry, John Q. Xiao, and Y. F. Li
- Subjects
Materials science ,Metallurgy ,General Physics and Astronomy ,chemistry.chemical_element ,Giant magnetoresistance ,Giant magnetoimpedance ,Tungsten ,Amorphous solid ,Ferromagnetism ,chemistry ,Electrical resistivity and conductivity ,Skin effect ,Tube (fluid conveyance) ,Composite material - Abstract
Soft magnetic crystalline alloys have been fabricated in a tube form by electrodepositing magnetic FeNi and FeNi–Al2O3 onto W fibers with a diameter of 25 μm. Fine Al2O3 particles have also been incorporated into the magnetic matrix to improve mechanical properties. As-prepared materials are not magnetically soft. With heat treatment, the magnetic properties of these composites are similar to commercial bulk soft FeNi alloys. A giant magnetoimpedance value as large as 190% has been found in as-prepared FeNi-W with a magnetic layer thickness of 20 μm. This value is comparable to GMI observed in amorphous magnetic wires. Experiments also show that GMI values decrease when the Al2O3 content increases in a range from 0 to 7.0 at. %. This behavior is due to the increase in electrical resistivity and magnetic permeability of the samples that modifies the skin effect.
- Published
- 2000
27. Microstructural Effect of Magnetic Properties of FeCo-based Soft Magnetic Alloys
- Author
-
R. H. Yu, B. E. Lorenz, S. Basu, George C. Hadjipanayis, Y. F. Li, John Q. Xiao, and Y. Zhang
- Subjects
Materials science ,Condensed matter physics ,Precipitation (chemistry) ,Neutron diffraction ,Coercivity ,Condensed Matter Physics ,Microstructure ,Grain size ,Electronic, Optical and Magnetic Materials ,Magnetization ,Magnetic shape-memory alloy ,Phase (matter) ,Electrical and Electronic Engineering ,Instrumentation - Abstract
We have systematically investigated the effect of microstructure on the magnetic properties of FebalCo49V1.9, FebalCo49V1.9Nb0.3, FebalCo27Cr0.6Ni0.6, FebalCo27Cr0.6Ni0.6C0.3 alloys in a temperature range of 20-700 °C. The effects of microstructure, the grain size, second phase precipitation, density of dislocation, and structural ordering parameter have been separated each other and been determined. The second phase precipitation which appears in high temperature aged samples causes the magnetic properties to deteriorate significantly. The increase of the structural ordering parameter, which was determined by neutron diffraction, improves the magnetic properties. The grain size mainly affects the coercivity field.
- Published
- 1999
28. Magnetic properties and giant magnetoresistance in La0.67Ca0.33MnOx bulk material
- Author
-
X. X. Zhang, R. H. Yu, Y. Xin, Javier Tejada, G. F. Sun, and K. W. Wong
- Subjects
Crystal ,Magnetization ,Materials science ,Physics and Astronomy (miscellaneous) ,Magnetoresistance ,Condensed matter physics ,Curie temperature ,Giant magnetoresistance ,Atmospheric temperature range ,Néel temperature ,Magnetic field - Abstract
The magnetic and transport properties of a perovskite‐type crystal sample with a nominal composition La0.67Ca 0.33MnOx have been investigated in the temperature range from 5 to 300 K with applied magnetic fields up to 5 T. Magnetization data obtained in the zero‐field‐cooled process exhibit the magnetic behavior with a Neel temperature, TN∼50 K and Curie temperature, TC∼300 K. The interesting feature in the temperature dependence of magnetoresistance is the appearance of a peak at T∼50 K, with value Δρ/ρ=[ρ(0)−ρ(5 T)]/ρ(5 T)=1300% at the Neel temperature, rather than at Curie temperature.
- Published
- 1996
29. Approach to Synthesizing Bulk, Fully Dense Anisotropic Nanocomposite Rare Earth Permanent Magnets
- Author
-
S. Liu, B. Cui, S. Bauser, R. Leese, J. S. Hilton, R. H. Yu, A. Kramp, J. Dent, and D. Miles
- Subjects
Nanocomposite ,Nuclear magnetic resonance ,Condensed matter physics ,Chemistry ,Magnet ,Rare earth ,General Medicine ,Anisotropy - Published
- 2003
30. Bacterial lactoferrin receptors
- Author
-
A B, Schryvers, R, Bonnah, R H, Yu, H, Wong, and M, Retzer
- Subjects
Lactoferrin ,Bacteria ,Bacterial Proteins ,Mutation ,Operon ,Receptors, Cell Surface ,Carrier Proteins ,Cation Transport Proteins ,Bacterial Outer Membrane Proteins ,Signal Transduction - Abstract
Lactoferrin is thought to play a pivotal role in prevention of infection in the host and its ability to sequester iron from potential pathogens has been considered an important component of its antimicrobial function. A number of bacterial species in the Neisseriaceae have developed a mechanism for acquiring iron directly from this host glycoprotein which involves surface receptors capable of specifically binding lactoferrin. Initial attempts at identifying the receptor proteins in Neisseria and Moraxella species using affinity isolation with immobilized lactoferrin under high stringency conditions presumptively identified a single 100 kDa receptor protein, LbpA (formerly Lbp1). Under modified affinity isolation conditions a second 84 kDa lactoferrin binding protein was isolated and had been presumptively identified as LbpB. This protein was not isolated from a CopB-ve isogenic mutant of Moraxella catarrhalis, indicating that it was in fact CopB. However, another lactoferrin binding protein isolated under high stringency conditions, that comigrated with LbpA in most, but not all, M. catarrhalis strains, was identified by convalescent antisera. Its biochemical properties suggested that it indeed was LbpB. The identity of these proteins was confirmed by preparing isogenic mutants with the lbpA and lbpB genes. Growth studies with isogenic mutants deficient in LbpB, LbpA, CopB or FbpA were performed to evaluate their role in iron acquisition from lactoferrin. LbpA and FbpA were essential for this process, supporting prior models of the iron acquisition pathway. LbpB was not essential which is remniscent of studies with the bacterial transferrin receptors. The isogenic CopB-ve isogenic mutants were deficient in iron acquisition from both transferrin and lactoferrin, suggesting that it is a key component in both pathways. A model providing an alternate explanation of the data is presented. The role and surface accessibility of the lactoferrin receptor proteins suggests that they might be useful vaccine antigens and the preferentially reactivity of convalescent antisera with LbpB suggests that it may be the prime candidate.
- Published
- 1998
31. Structure dependent photoluminescence and magnetic properties of Co:ZnS nanostructures
- Author
-
R H Yu, N Yang, X F Liu, and X B Chen
- Subjects
Materials science ,Photoluminescence ,Nanostructure ,Nanotechnology ,Condensed Matter Physics ,Atomic and Molecular Physics, and Optics ,Crystallinity ,Ferromagnetism ,Chemical engineering ,Nanocrystal ,Nanorod ,Mathematical Physics ,Stoichiometry ,Visible spectrum - Abstract
Co:ZnS nanostructures have been synthesized via the solvothermal method by modifying the stoichiometry of Zn and S sources in the solvothermal process. The structure and morphology analysis demonstrates that the increase of the Zn/S molar ratio leads to changes in the morphology and structure, from Co:ZnS nanorods and hexagonal nanocrystals to core–shell Co:ZnS/ZnO nanocrystals. The photoluminescence spectrum for Co:ZnS/ZnO exhibits strong visible light emissions due to the presence of a large amount of structural defects, whereas the emissions for Co:ZnS nanorods almost disappear because of the high crystallinity. All the samples display obvious room-temperature ferromagnetism. The saturated magnetic moment of the samples strongly depends on the concentration of structural defects in the nanostructures and can be effectively enhanced by the introduction of abundant defects.
- Published
- 2013
32. Pacing or ablation: which is better for paroxysmal atrial fibrillation related tachycardia-bradycardia syndrome?
- Author
-
Jian-Zeng Dong, R.-B. Tang, X I N Du, C.-H. Sang, R.-H. Yu, D.-Y. Long, Mohamed Salim, C.S. Ma, Rong Bai, and Y.-W. Chen
- Subjects
medicine.medical_specialty ,business.industry ,Paroxysmal atrial fibrillation ,medicine.medical_treatment ,Cardiac Ablation ,Ablation ,Tachycardia-bradycardia syndrome ,law.invention ,law ,Internal medicine ,medicine ,Cardiology ,Artificial cardiac pacemaker ,Sinus rhythm ,Bradycardia-tachycardia syndrome ,Cardiology and Cardiovascular Medicine ,business ,Anti-Arrhythmia Agents - Published
- 2013
33. First Report of Botrytis Leaf Blight and Fruit Rot on Schisandra chinensis Caused by Botrytis cinerea in China
- Author
-
J. Gao, Jian Wang, Xiangjing Wang, and R. H. Yu
- Subjects
food.ingredient ,biology ,fungi ,food and beverages ,Plant Science ,Botryotinia fuckeliana ,biology.organism_classification ,Conidium ,food ,Botany ,Blight ,Potato dextrose agar ,Chamelaucium uncinatum ,Agronomy and Crop Science ,Botrytis cinerea ,Schisandra ,Botrytis - Abstract
Schisandra (Schisandra chinensis (Turcz.) Baill) is a perennial plant belonging to Magnoliaceae. It is a very important medicinal herb in China and is mainly used for treatment of insomnia and memory decay. From July to September 2008, an unknown leaf blight and fruit rot on schisandra were first observed at Jingyu County, Jilin Province. The same symptoms were detected in other areas of Jilin Province, such as Ji'an City, Baishan City, and Hunchun City. Initially, some small, brown spots appeared on the tip or margin of the leaves. Light brown or brown necrotic lesions developed and eventually covered entire leaves. Seriously affected leaves were rolled or distorted and eventually became completely dry and brittle. Small spots appeared on the surface of mature fruits, coalesced, and the fruits finally dropped. Gray mycelia and conidiophores developed on the diseased leaves and fruits. To isolate the causal agent, conidia and conidiophores were scraped aseptically from the internal tissues, suspended in sterile water, and streaked onto the surface of potato dextrose agar (PDA). Single-hyphal tips were transferred on PDA and the isolated fungus was identified as Botrytis cinerea Pers.: Fr. on the basis of its morphological characteristics and internal transcribed spacer (ITS) sequence. Colonies of B. cinerea on PDA were colorless at first and became gray to brown 20 days later with the mycelium growth and conidia producing in cultures. Conidia are single celled, lemon shaped, colorless to a light color, and 4.4 to 15.0 × 7.0 to 10.0 μm. Sclerotia formed about 1 week later, were black-brown and varied in size (2.0 to 5.0 × 2.0 to 4.0 mm) and shape. The ITS region of rDNA was amplified from DNA extracted from single-spore isolate BC12 of B. cinerea using primers ITS4/ITS5 and sequenced (GenBank Accession No. GU724512), BLAST analysis (1) of the 535-bp segment showed 99% similarity with the sequence of Botryotinia fuckeliana (perfect stage of B. cinerea). Pathogenicity tests were carried out on healthy schisandra plants that were 4 years old. After the surface of the leaves and fruits was disinfected with 5% sodium hypochlorite, a conidial suspension of 105 conidia/ml was sprayed on 10 schisandra leaves, and plugs of the fungus obtained from the colony margins were transferred onto a 3- × 3-mm wound on the surface of disinfected fruit. Ten control schisandra leaves and 10 fruits were inoculated at the same time. Plants were covered with polyethylene bags and incubated at 25°C in a greenhouse with relative humidity of 85% for 3 days. Similar symptoms to those observed on diseased leaves and fruits in the field were observed on inoculated schisandra leaves and fruits 7 days after inoculation, whereas control leaves and fruits showed no symptoms. The pathogen was successfully reisolated. The gray mold disease caused by B. cinerea was reported in many plants, such as Lavandula stoechas and Chamelaucium uncinatum in Italy (2,3). However, to our knowledge, this is the first report of gray mold disease of schisandra caused by B. cinerea in China. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) A. Garibaldi et al. Plant Dis. 94:968, 2009. (3) A. Garibaldi et al. Plant Dis. 94:380, 2010.
- Published
- 2011
34. Growth of mixed phased films of γ-Fe2O3and half metallic Fe3O4using (100) MgO/Fe under layer for spin electronic devices
- Author
-
R H Yu, M L Wang, and S Nakagawa
- Subjects
History ,Materials science ,Analytical chemistry ,Substrate (electronics) ,Partial pressure ,Epitaxy ,Computer Science Applications ,Education ,chemistry.chemical_compound ,Crystallography ,Crystallinity ,chemistry ,Sputtering ,Electrical resistivity and conductivity ,Layer (electronics) ,Magnetite - Abstract
Half metallic magnetite films using (100) MgO/Fe under layer deposited at room temperature were prepared using facing targets sputtering method. X-ray diffractometry and TEM analyses confirmed epitaxial growth of (100) oriented Fe3O4 layer on (100) oriented MgO under layer prepared on 5nm-thick Fe buffer layer on glass substrates. Resistivity analyses clarified that higher oxygen partial pressure caused higher oxidation of Fe ions in the films which tend to result in γ-Fe2O3. Substrate heating is effective to improve crystallinity and magnetic properties of Fe3O4 film. Oxygen partial pressure of 7.5%, substrate temperature of 150 °C and sputtering discharge current of 0.45A was suitable to prepare magnetite Fe3O4 film with (100) preferential orientation and good magnetic properties.
- Published
- 2011
35. Electronic Surface State and Plasmon-Phonon Coupled Excitations at the surface of Modulation-doped GaAs/AlGaAs Multiquantum Wells: A Study of High-Resolution Electron-Energy-Loss Spectroscopy(HREELS)
- Author
-
R. H. Yu
- Abstract
A selfconsistent framework for study of the surface electronic structure of finite superlattices has been proposed. Our emphasis is on the influence of accumulation or depletion layer on the surface states (Tamm states). We have used a modulated doping profile, including an accumulation or a depletion surface layer, in our selfconsistent calculations of potential and carrier density profile. We have found the existence of Tamm states above(depletion layer) or below(accumulation layer) the superlattice miniband. One of the Tamm states found crosses the Fermi energy in the energy gap when the depletion effect, resulting from dangling bonds, defects, impurities, etc, near the surface increases. In our case, near the top layer of the superlattice the depletion region was formed as a result of the pinning of the Fermi level below its position in intrinsic GaAs due to the midgap surface states.
- Published
- 1993
36. Purification and some properties of peroxidase isozymes from pineapple stem
- Author
-
H Y, Sung, R H, Yu, and C T, Chang
- Subjects
Isoenzymes ,Kinetics ,Peroxidases ,Ammonium Sulfate ,Fruit ,Hydrogen-Ion Concentration - Abstract
The enzyme peroxidase is widely distributed among the higher plants. Isozymes of peroxidase are known to occur in a variety of tissues in a large number of plant species. In this study, peroxidase isozymes were purified from the extract of pineapple stem through successive steps of ammonium sulfate fractionation, CM-Sepharose CL-6B chromatographies and DEAE-Sepharose CL-6B chromatographies. By these steps, twelve isozymes of peroxidase were obtained. Some properties of the isozymes were studied and compared.
- Published
- 1993
37. Role of oxygen vacancies in tuning magnetic properties of Co-doped SnO2 insulating films
- Author
-
X. F. Liu, Yuanwei Sun, and R. H. Yu
- Subjects
Materials science ,Magnetic moment ,Annealing (metallurgy) ,Band gap ,Analytical chemistry ,General Physics and Astronomy ,chemistry.chemical_element ,Partial pressure ,Sputter deposition ,Oxygen ,Condensed Matter::Materials Science ,Nuclear magnetic resonance ,chemistry ,Ferromagnetism ,Condensed Matter::Superconductivity ,Thin film - Abstract
A series of films deposited under different oxygen partial pressures and annealed under different atmospheres were prepared to investigate the role of oxygen vacancies in tuning magnetic properties of Co-doped SnO2 films. The inclusive Co in SnO2 is in the 2+ state and substitutes for the Sn4+ site. Intrinsic room temperature ferromagnetism is observed in all films, which is not carrier mediated, but coexists with the dielectric behavior. A maximum magnetic moment of 2.37 μB∕Co is achieved by vacuum annealing due to the increase and diffusion of oxygen vacancies rather than the improvement of crystallinity of the film, and the magnetic moment decreases considerably after air annealing or increasing the oxygen partial pressure during deposition. The changes of oxygen vacancy concentration and distribution are indirectly demonstrated by the relative shifts of Co 2p3∕2 peaks in XPS spectra. The band gap of Co-doped SnO2 film is larger than that of pure SnO2 film, suggesting the influence of inclusive Co on t...
- Published
- 2007
38. Precipitation and high temperature magnetic properties of FeCo-based alloys
- Author
-
R. H. Yu and J. Zhu
- Subjects
Crystallography ,Materials science ,Magnetic domain ,Condensed matter physics ,Ferromagnetism ,Magnetic shape-memory alloy ,Volume fraction ,Nucleation ,General Physics and Astronomy ,Coercivity ,Microstructure ,Magnetic hysteresis - Abstract
The microstructure and high temperature magnetic properties of Fe–Co–2V and Fe–Co–2V–0.3Nb alloys have been investigated. Aging at 600 °C, γ2 phases precipitate whose size and volume fraction increase with increasing aging time. A roughly linear relationship between magnetic coercivity Hc and volume fraction of the γ2 precipitates was observed. Addition of Nb facilitates nucleation and growth of the γ2 precipitates, resulting in a dramatic deterioration of soft magnetic properties of the alloys. A pinning effect of the γ2 precipitates on the magnetic domain wall has been observed by Lorenz electron microscopy.
- Published
- 2005
39. Dimensionality Reduction and Generation of Human Motion.
- Author
-
S. Qu, L. D. Wu, Y. M. Wei, and R. H. Yu
- Subjects
NONLINEAR systems ,GAUSSIAN processes ,MACHINE learning ,PROBABILITY theory ,CONSTRAINT satisfaction ,KINEMATICS ,KERNEL functions - Abstract
To reuse existing motion data and generate new motion, a method of human motion nonlinear dimensionality reduction and generation, based on fast adaptive scaled Gaussian process latent variable models, is proposed. Through statistical learning on motion data, the motion data are mapped from high-dimensional observation space to low-dimensional latent space to implement nonlinear dimensionality reduction, and probability distributing of posture space which measures the nature of posture is obtained. The posture which meets constraints and has maximal probability can be computed as the solution of inverse kinematics. This method can avoid cockamamie computation and posture distortion existing in traditional inverse kinematics. The experiments show that our method has higher convergence velocity and precision and extends editing range of motion by adapting motion editing direction. [ABSTRACT FROM AUTHOR]
- Published
- 2013
40. Structure dependent photoluminescence and magnetic properties of Co:ZnS nanostructures.
- Author
-
X. B. Chen, N. Yang, X. F. Liu, and R. H. Yu
- Published
- 2013
- Full Text
- View/download PDF
41. Effect of Zr on the microstructure, magnetic domain structure, microchemistry and magnetic properties in Sm(CobalCu0.08Fe0.10Zrx)8.5 magnets.
- Author
-
W M Gong, R S Gao, H B Feng, R H Yu, Y Zhang, and G C Hadjipanayis
- Subjects
ANALYTICAL chemistry ,MICROMECHANICS ,MAGNETIC properties ,CRYSTAL growth - Abstract
The effect of Zr on the microstructure, microchemistry and coercivity of Sm(CobalCu0.08Fe0. 10Zrx)8.5 (x = 0-0.10) magnets has been systematically investigated. The presence of Zr is responsible for the formation of the lamella structure. With increasing Zr content, a cellular-like structure gradually develops while the density of the lamella phase increases. A proper Zr content (0.015-0.060 at.%) is the key to form a complete and uniform cellular structure. Microchemistry data show that the Cu content in the cell boundaries in the magnet with 0.04 at.% Zr is higher than that with 0.015 at.% Zr, although both samples have similar microstructure morphologies. Higher coercivity is obtained in samples where the domain walls (DWs) are pinned at cell boundaries. For Zr-free or higher Zr samples, DWs nucleated at grain boundaries are responsible for the reduction in coercivity. During isothermal ageing, at a fixed Zr content, the coercivity is developed with increasing ageing time. These results clearly show that Zr plays an important role in the formation of a uniform cellular structure with the right microchemistry and that a critical amount of Zr is needed for the optimum magnetic properties. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.