bluuebunny/crossref_metadata_2025_split huggingface dataset:
Room Temperature Ferromagnetism in Powder Form of Sn1-xCrxO2 (x = 0.01, 0.02, 0.03, 0.04 and 0.05) Solid Solution
Authors: Xu Kun , Izumi Mitsuru , Yanagisawa Osami , Ida Tetsuya 
Published: January 2010

AbstractStructural and magnetic properties were investigated in the mixed powders of Sn1-xCrxO2 (x = 0.01, 0.02, 0.03, 0.04 and 0.05) in nominal composition. The lattice parameter observed in (110) x-ray diffraction indicates two step changes with increasing Cr content. The occupation of Cr ion at the interstitial position leads to elongation of the lattice parameter for x = 0.01 to x =0.03. Then, the Cr3+ ions are remarkably substituted into the Sn4+ ion site for x = 0.04 to x = 0.05, which results in shortening of the lattice. The lattice parameters for x = 0.01 and 0.02 are larger than x = 0.03 to 0.05. The room temperature ferromagnetism appeared in the sample with x = 0.01 and reaches maximum at the doping rate of x = 0.02; while the magnetization decreases for x > 0.02 was observed. Present study clearly shows the existence of correlation between appearance of ferromagnetism and the structural change.
Kinetics and Mechanism of Formation of GaN from β-Ga2O3 by NH3
Authors: Sakai Toshiki , Kiyono Hajime , Shimada Shiro 
Published: January 2010

AbstractNitridation of β-Ga2O3 to GaN in an atmosphere of NH3/Ar was investigated from the view points of kinetic results by thermogravimetric analysis (TGA) and microstructural observation. TGA and X-ray powder diffraction results showed that the nitridation of Ga2O3 to GaN starts at about 650°C and decomposition of GaN formed occurs from 870°C. Isothermal TGA results showed that the nitridation proceeds linearly with time at 800 – 1000°C. Microstructural observation of the samples nitrided at 800°C showed that fine GaN particles (∼50 nm size) deposit on surfaces of Ga2O3 particles at an early stage, and the deposits grow with progress of the nitridation.
Low-resistance Ohmic Contacts to N-face p-GaN for the Fabrication of Functional Devices
Authors: Han Seung-Cheol , Kim Jae-Kwan , Kim jun Young , Kwak Joon Seop , Kim Kangho , Kim Jong Kyo , Schubert E. , Kim Kyoung-Kook , Lee Ji-Myon 
Published: January 2010

AbstractThe electrical properties of Ni-based ohmic contacts N-face p-type GaN are presented. The specific contact resistance of N-face p-GaN exhibits a liner decrease from 1.01 × cm2 to 9.05 × 10-3 Ω cm2 for the as-deposited and the annealed Ni/Au contacts, respectively, with increasing annealing temperature Furthermore, the specific contact resistance could be decreased by four orders of magnitude to 1.03 × 10-4 Ω cm2 as a result of surface treatment using an alcohol-based (NH4)2S solution. The depth profile data measured by the intensity of O1s core peak in the x-ray photoemission spectra showed that the alcohol-based (NH4)2S treatment was effective in removing of the surface oxide layer of GaN. In addition, a Ga 2p core-level peak showed a red-shift of binding energy by 0.3 eV by alcohol-based (NH4)2S treatment, indicating that the surface Fermi level was shifted toward the valence-band edge. Thus, the low ohmic contact behavior observed in our treated sample might be explained in terms of the removal of the oxide layer and reducing the barrier heights by reduced band-bending effect.
Recent Advances in Wide Bandgap Semiconductor Biological and Gas Sensors
Authors: Pearton S.J. , Ren F. , Wang Yu-Lin , Chu B. H. , Chen K. H. , Chang C. Y. , Lim Wantae , Lin Jenshan 
Published: January 2010

AbstractThere has been significant recent interest in the use of surface-functionalized thin film and nanowire wide bandgap semiconductors, principally GaN, InN, ZnO and SiC, for sensing of gases, heavy metals, UV photons and biological molecules. For the detection of gases such as hydrogen, the semiconductors are typically coated with a catalyst metal such as Pd or Pt to increase the detection sensitivity at room temperature. Functionalizing the surface with oxides, polymers and nitrides is also useful in enhancing the detection sensitivity for gases and ionic solutions. The wide energy bandgap of these materials make them ideal for solar-blind UV detection, which can be of use for detecting fluorescence from biotoxins. The use of enzymes or adsorbed antibody layers on the semiconductor surface leads to highly specific detection of a broad range of antigens of interest in the medical and homeland security fields. We give examples of recent work showing sensitive detection of glucose, lactic acid, prostate cancer and breast cancer markers and the integration of the sensors with wireless data transmission systems to achieve robust, portable sensors.
A novel functionalization of AlGaN/GaN-pH-Sensors for DNA-sensors
Authors: Linkohr Stefanie , Schwarz S. U. , Krischok S. , Lorenz P. , Nakamura T. , Polyakov V. , Cimalla V. , Nebell C. , Ambacher O. 
Published: January 2010

AbstractAlGaN/GaN pH sensitive devices were functionalized and passivated for the use as selective bio-sensors. For the passivation, a multilayer of SiO2 and SiNx is proposed, which stabilizes the pH-sensor, is biocompatible and has no negative impact on the following bio-functionalization. The functionalization of the GaN-surface was achieved by covalent bonding of 10-amino-dec-1-ene molecules by a photochemical process. After two different surface preparations islands of TFAAD are growing on the sensor surface by exposure with UV-light. In dependence on the surface pre-treatment and the illumination wavelength the first monolayer is completed after 3 h or 7 h exposure time dependent on the pre-treatment and illumination wavelength. Further exposure results in thicker films as a consequence of cross polymerization. The bonding to the sensor surface was analyzed by X-ray photoelectron spectroscopy, while the thickness of the functionalization was determined by atomic force microscopy scratching experiments. These functionalized devices based on the pH-sensitive AlGaN/GaN ISFET will establish a new family of adaptive, selective biomolecular sensors such as selective, reusable DNA sensors.
Short-Wavelength Intersubband Light Emission from Optically Pumped GaN/AlN Quantum Wells
Authors: Paiella Roberto , Driscoll Kristina , Liao Yitao , Bhattacharyya Anirban , Zhou Lin , Smith David J. , Moustakas Theodore D. 
Published: January 2010

AbstractDue to their large conduction-band offsets, GaN/Al(Ga)N quantum wells are currently the subject of extensive research efforts aimed at extending the spectral range of intersubband optoelectronic devices towards shorter and shorter wavelengths. Here we report our recent measurement of optically pumped intersubband light emission from GaN/AlN quantum wells at the record short wavelength of about 2 μm. Nanosecond-scale optical pulses are used to resonantly pump electrons from the ground states to the second excited subbands, followed by radiative relaxation into the first excited subbands. The intersubband origin of the measured photoluminescence is confirmed via an extensive study of its polarization properties and pump wavelength dependence.
CH2 group migration between the H-terminated 2×1 reconstructed {100} and {111} surfaces of diamond
Authors: Richley James C. , Harvey Jeremy N. , Ashfold Mike N.R. 
Published: January 2010

AbstractVarious possible routes for the migration of a CH2 group between the H-terminated 2×1 reconstructed {100} surface and the H-terminated {111} surface of diamond have been explored using a hybrid quantum mechanical/molecular mechanical method. The calculated energies suggest that movement of such surface bound species across step edges should be a facile process under typical diamond growth conditions, and that such migrations are significant contributors to the observed morphologies of diamond grown by chemical vapor deposition methods.
Pressure-induced Structural Phase Transition of Carbon Nanotubes into New Nanostructured Carbon Solids
Authors: Sakurai Masahiro , Saito Susumu 
Published: January 2010

AbstractWe study pressure-induced structural phase transition of carbon nanotubes using the constant-pressure tight-binding molecular-dynamics simulation. The systems studied are nanotube bundles composed of (6,6) armchair nanotube and/or (7,4) chiral nanotube, which are reported to be the nanotubes relatively abundant in experimentally purified sample. We find that the nanotube bundles transforms into a new phase that consist of graphitic ribbons and diamond blocks, “graphitic nanoribbon solid”. It is also found that sp3-rich phases obtained from the armchair nanotubes possess an anisotropic network and have high hardness which is comparable to that of cubic diamond. In the case of the bundles containing chiral nanotubes, on the other hand, amorphous diamond phase is obtained. Based on the local-density approximation in the density-functional theory, we also investigate the energetics and electronic structure of some of new carbon phases obtained in the molecular-dynamics study.
Flexible and Transparent SWCNT Electrodes for Alternating Current Electroluminescence (ACEL) Devices
Authors: Schrage Christian , Kaskel Stefan 
Published: January 2010

AbstractThe application of transparent single-walled carbon nanotube (SWCNT) electrodes in rigid and flexible alternating current electroluminescence (ACEL) devices is demonstrated. SWCNT thin film electrodes (50 – 160 nm) were made using a spray-coating process suitable for adjusting transparency and sheet resistance. The emission intensity was as high as for indium tin oxide (ITO) based ACEL devices with transparencies comparable to ITO coated polymer slides.
The Effect of Ion Delivery on Polypyrrole Strain and Strain Rate under Elevated Temperature
Authors: Keng Yenmei , Pillai Priam Vasudevan , Hunter Ian W 
Published: January 2010

AbstractConducting polymers can act as actuators when an electrochemical stimulus causes the materials to undergo volumetric changes. Ion flux into the polymer causes volumetric expansion and ion outflow causes contraction. Polypyrrole is an attractive actuator material due to its ability to generate up to 30 MPa active stress and 10% to 26% maximum strain with voltage supply lower than 2 V. The polymer’s mechanical performance depends upon the solvent used and the dominating ion species. In this study, we used 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF6) to characterize the effect of temperature increase on ion flow and how it contributes to strain and maximum strain rate of polypyrrole. In this solvent, the cation BMIM+ diffuses in and out of the polymer under applied voltage to cause strain changes. For approximately each increment of 10°C from 27°C to 83°C, isotonic tests were done with +/-0.8 V square pulses, using a custom built device that is capable of performing temperature controlled dynamic mechanical analyses and electrochemistry simultaneously. Results showed that, independent of voltage polarity, from 27 to 83°C the strain increased from 0.4% to 2.0%. Both the maximum charge and strain rate rates increased with temperature, and were higher at positive voltage than at negative voltage throughout the same temperature range. Positive voltage caused the maximum strain rate to increase exponentially from 0.1 %/s to 0.67 %/s, while negative voltage caused it to increase more linearly from 0.06 %/s to 0.23 %/s. The results suggest that the increase in strain resulted from the charge delivered to the polymer in higher quantities at higher temperature. Furthermore, BMIM+ ions are expelled faster than those being attracted in to the polymer, perhaps due to the ions preferentially remaining in the bulk solution. As the temperature increased, the ionic mobility increased and as a result, BMIM+ ions are expelled back into the solvent even faster.
Thin Film Bulk Acoustic Wave Resonators for Continuous Monitoring in the Physical, Chemical and Biological Realms
Authors: Ashley Greg , Luo Jack , Kirby Paul , Butler Timothy , Cullen David 
Published: January 2010

AbstractA transducer that can act as a highly sensitive and reliable universal sensor capable of detecting and continuously monitoring changes in the physical, chemical and biological domains is a potentially useful scientific tool. The Thin Film Bulk Acoustic Wave Resonator (FBAR) is a microwave device that is becoming increasingly recognised as a universal transduction platform with the added advantage of potential integration into CMOS architecture and array-like formats. This work shows preliminary results on FBAR where a continuous monitoring arrangement demonstrated the capability of FBAR to respond to changes in physical parameters such as temperature and light levels, the work goes on further to show the ability of FBAR to respond to changes in humidity in a gas flow and can have sensitivity increased with the addition of hygroscopic polymers on its surface and finally how FBAR can be adapted to act as a biosensor in the form of an immunosensor with sensitivity some orders of magnitude greater than traditional lower frequency bulk acoustic wave platforms.
Thickness-Dependant Electrical Characteristics of Nitrogen-Doped Polycrystalline 3C-SiC Thin Films Deposited by LPCVD
Authors: Lei Man I , Lee Te-Hao , Mehregany Mehran 
Published: January 2010

AbstractThe effect of film thickness on the electrical resistivity of heavily-nitrogen-doped polycrystalline SiC (poly-SiC) thin films is investigated. The resistivity of poly-SiC thin films decreases by a factor of ˜7 for thickness increasing from 100 nm-thick to 1.78 μm-thick; the resistivity begins to stabilize as thickness approaches 1 μm. The increased resistivity for the thinner films is shown to be related to the grain boundary effect. Secondary ion mass spectrometry indicates a nitrogen concentration of 9×1020 atoms/cm3 in the films. However, Hall measurements reveal that only 45% of the dopants are electrically active in the 100 nm-thick film. The percentage of active dopants rises to 80% when film thickness increases to 680 nm. From the studies of surface roughness and microstructure, it is seen that small grains are formed at the initial stage of deposition, which then grow into larger columnar grains as film thickness increases. The presence of a large density of grain boundaries and limited grain growth for the very thin films contribute to increased electrical resistivity from increased trapped mobile carriers and reduced carrier mobility. The free carrier trapping phenomenon can further be observed in the temperature-dependence of resistance measurement.
Polycrystalline Silicon-Germanium Electrode Contact Technology Improvement for MEMS Applications
Authors: Claes Gert , Severi Simone , Decoutere Stefaan , Celis Jean-Pierre , Witvrouw Ann 
Published: January 2010

AbstractPoly-SiGe has quite some potential as structural MEMS layer for CMOS-MEMS integration. However, the contact resistance between SiGe MEMS and top CMOS metal should be low to avoid parasitic effects that would reduce the system performance. In this paper, a new and simple approach is proposed to achieve a low contact resistance between a top CMOS interconnect and a boron doped poly-SiGe MEMS layer deposited at 450 °C. The use of a 20 nm soft sputter etch in combination with a Ti-TiN (5-10 nm) interlayer results in a contact resistivity of 6.2 ± 0.4 × 10-7Ωcm2that is lower than previously reported. The uniformity of the contact resistivity across the wafer is also better than the state-of-the-art value.
Densely-Packed Microbowl Array with Balanced Dielectrophoretic Forces for Single-Cell Microarray
Authors: Im Maesoon , Kim Dong-Haan , Lee Joo-Hyung , Yoon Jun-Bo , Choi Yang-Kyu 
Published: January 2010

AbstractIn this paper, we demonstrate a perfectly-ordered microbowl array with balanced dielectrophoresis (DEP) for a high-throughput single-cell analysis. In order to fabricate well-ordered microbowl array in a large area, we utilized three-dimensional diffuser lithography for photoresist mold and nickel electroplating technique for final microbowl structures on a silicon substrate. Single microbowl has six sharp apexes surrounding the microbowl perimeter. Each microbowl has a diameter of 10 μm, and a height of 9 μm, which can be controllable by patterns on mask and lithography conditions. To investigate feasibility for application to the microbowl array as a single-cell microarray, we used latex beads of 6.4 μm in an average diameter to be captured by dielectrophoretic force. The nickel microbowl array densely packed with a hexagonal geometry played as a bottom electrode, and an ITO-coated glass covered the nickel microbowl array as a top electrode while keeping a uniform gap between two electrodes. After injecting solution containing latex beads through the gap, we applied an AC signal (2 VPP, 1 MHz) between two electrodes to induce high electric field near the sharp apexes of the single microbowl. A negative DEP trap is formed at the center of the single microbowl with balanced DEP force from the six apexes. The experimental result shows that injected latex beads had been successfully and uniformly aligned and trapped at the microbowl array sustained by negative DEP.
Migration of Marrow Stromal Cells in Response to Sustained Release of Stromal-Derived Factor-1α from Poly(lactide ethylene oxide fumarate) Hydrogels
Authors: He Xuezhong , Ma Junyu , Jabbari Esmaiel 
Published: January 2010

AbstractStromal derived factor-1α (SDF-1α) is an important chemokine in stem cell trafficking and plays a critical role in the homing, osteogenesis as well as angiogenesis of bone marrow stromal (BMS) cells. The objective of this work was to investigate the release characteristics of SDF-1α from the degradable poly(lactide ethylene oxide fumarate) (PLEOF) hydrogels and to determine the effect of sustained release of SDF-1α on migration of BMS cells. Three PLEOF macromers with PLA content of 6, 9, and 24 by weight were synthesized by condensation polymerization. The cumulative amount of biologically-active SDF-1α released from the PLEOF hydrogels after 3 weeks was between 20-25% of the initial loading and was independent of PLA/PEG ratio in the hydrogel. The migration of BMS cells in response to the time-release SDF-1α from PLEOF hydrogels closely followed the release kinetics of SDF-1α from the hydrogels. Results demonstrate that migration of BMS cells was significantly increased by the sustained release of SDF-1α from PLEOF hydrogels.
Functionalization of Nanofibrous Spiral Structured Scaffolds for Bone Tissue Engineering
Authors: Wang Junping , Yu Xiaojun 
Published: January 2010

AbstractIn the previous studies, we have successfully developed a novel spiral structured nanofibrous scaffolds with improved osteoconductivity for bone tissue engineering. The spiral structure design facilitates the nutrient transport and waste removal, and allows uniform cellular growth and distribution within the scaffolds, thus enhanced the bioactivity of the scaffolds. In this chapter, HAP and BMP-2 were incorporated within the nanofibrous spiral scaffolds in order to enhance the osteoinductivity of the established system. The effect of the blending materials was evaluated through cell proliferation, cell differentiation of human osteoblast cells seeded on the scaffolds and cultured for 4 and 8 days. The results has demonstrated that the functionalization of PCL nanofibrous spiral scaffolds leads to higher ALP expression level and increased amount of mineralization level however lower cell proliferation rate.
Removal and successful re-implantation of a customized interpositional knee device following an early postoperative infection: A case report
Authors: Koeck Franz , Rath Bjoern , Springorum Hans-Robert , Tingart Markus , Grifka Joachim , Beckmann Johannes 
Published: January 2010

Abstract
We report the first case of early postoperative infection after a medial hemiarthroplasty of the knee with a customized ConforMIS iForma™ interpositional device. The infection was treated successfully by revision surgery with implant removal and antibiotic therapy. Despite the additional diagnosis of rheumatoid arthritis that did not affect the treated knee, the preservation of bony and ligamentous structures enabled a successful re-implantation of another iForma™ implant 9 months later with good clinical results at follow-up examination 1 year postoperatively. This is very much in contrast to the extensive and complex revision surgery, with significant bone loss, in patients with infected unicompartmental or total knee arthroplasties. The iForma™ device may be an alternative treatment option in early and moderate unicompartmental arthritis of the knee, with easy revision with the same type of implant in the rare case of infection.
Differences in the body composition and biochemistry in women grouped as normal-weight, overweight and obese according to body mass index and their relation with cardiometabolic risk
Authors: Ozenoglu Aliye , Ugurlu Serdal , Can Gunay , Sarkis Cihat , Demirel Yeltekin 
Published: January 2010

Abstract
Morbidity of obesity-related diseases tends to increase due to a rise in the body mass index (BMI). We aimed to investigate how the body composition and biochemical parameters change while BMI increases in adult women were categorized as so: as normal weight, overweight and obese. Our objectives are to study the effects of those changes in the development of metabolic disturbances and to find out which parameters are the most sensitive to predict cardiometabolic risks. Three hundred and twenty two records of adult women (mean age: 38.62±12.71 year) who admitted to our unit concerning about losing or preserving their weights, were analyzed in the study. All patients had undergone anthropometric measurements and body composition analyses as well as some biochemical tests. Body composition analyses were performed by means of the Bioelectrical Impedance Analyzer (BIA). Increase in BMI significantly increased the body fat, blood sugar, insulin, triglyceride and uric acid levels. BMI and circumference of the waist were significantly and negatively correlated with the ratio of body water and lean mass/fat mass. However they were positively correlated with the ratio of fat mass and basal metabolism. Furthermore, it was also found that BMI and circumference of the waist were significantly and positively correlated with level of fasting blood sugar, insulin, triglyceride, homeostasis model assessment insulin resistance (HOMA-IR), uric acid and fibrinogen levels, and negatively correlated with high density lipoprotein (HDL) cholesterol level. In multiple regression analyses, circumference of waist measurements was significantly correlated with insulin, triglyseride and HDL, whereas the correlation between BMI and these parameters was not found significant. Total body fat mass (as %) showed significant correlation only with HDL-C level. It could be said that obesity which is a disorder that causes many health complications and affects the quality of life in the short and long term could be prevented or cured by keeping negative environmental conditions under control. According to our results, visceral adipose tissue (VAT) measurement was thought to be more related for metabolic and cardiovascular disorders rather than BMI. We also propose to test fasting blood glucose, insulin, triglyceride, HDL, fibrinogen, homocystein (HOM) levels along with VAT measurements to predict more truly about not only global cardiometabolic risk but also dementia in later life.