Modeling of temperature sensor built on thin silicon on insulator using advanced carrier-mobility model

An analytical device model to study the characteristics of the temperature sensor built on thin silicon film was developed. The device had higher maximum operating temperature due to larger minority-carrier exclusion length. The carrier-concentration distribution in the minority-exclusion region, exclusion length and the temperature dependence of the sensor resistance of the model was verified by device simulation. The model can be used to study the principle of the minority-carrier exclusion effect and also to guide the design of temperature sensors built on thin silicon film for high-temperature applications.published_or_final_versio

Characterization of volatile organic compounds at a roadside environment in Hong Kong: An investigation of influences after air pollution control strategies

Vehicular emission is one of the important anthropogenic pollution sources for volatile organic compounds (VOCs). Four characterization campaigns were conducted at a representative urban roadside environment in Hong Kong between May 2011 and February 2012. Carbon monoxide (CO) and VOCs including methane (CH4), non-methane hydrocarbons (NMHCs), halocarbons, and alkyl nitrates were quantified. Both mixing ratios and compositions of the target VOCs show ignorable seasonal variations. Except CO, liquefied petroleum gas (LPG) tracers of propane, i-butane and n-butane are the three most abundant VOCs, which increased significantly as compared with the data measured at the same location in 2003. Meanwhile, the mixing ratios of diesel- and gasoline tracers such as ethyne, alkenes, aromatics, halogenated, and nitrated hydrocarbons decreased by at least of 37%. The application of advanced multivariate receptor modeling technique of positive matrix factorization (PMF) evidenced that the LPG fuel consumption is the largest pollution source, accounting for 60 ± 5% of the total quantified VOCs at the roadside location. The sum of ozone formation potential (OFP) for the target VOCs was 300.9 μg-O3 m-3, which was 47% lower than the value of 567.3 μg-O3 m-3 measured in 2003. The utilization of LPG as fuel in public transport (i.e., taxis and mini-buses) contributed 51% of the sum of OFP, significantly higher than the contributions from gasoline- (16%) and diesel-fueled (12%) engine emissions. Our results demonstrated the effectiveness of the switch from diesel to LPG-fueled engine for taxis and mini-buses implemented by the Hong Kong Special Administrative Region (HKSAR) Government between the recent ten years, in additional to the execution of substitution to LPG-fueled engine and restrictions of the vehicular emissions in compliance with the updated European emission standards

Classification of migraine stages based on resting-state EEG power

© 2015 IEEE. Migraine is a chronic neurological disease characterized by recurrent moderate to severe headaches during a period like one month often in association with symptoms in human brain and autonomic nervous system. Normally, migraine symptoms can be categorized into four different stages: inter-ictal, pre-ictal, ictal, and post-ictal stages. Since migraine patients are difficulty knowing when they will suffer migraine attacks, therefore, early detection becomes an important issue, especially for low-frequency migraine patients who have less than 5 times attacks per month. The main goal of this study is to develop a migraine-stage classification system based on migraineurs' resting-state EEG power. We collect migraineurs' O1 and O2 EEG activities during closing eyes from occipital lobe to identify pre-ictal and non-pre-ictal stages. Self-Constructing Neural Fuzzy Inference Network (SONFIN) is adopted as the classifier in the migraine stages classification which can reach the better classification accuracy (66%) in comparison with other classifiers. The proposed system is helpful for migraineurs to obtain better treatment at the right time

Effects of Transduction of the bcl-2 Gene and of Nerve Growth Factor on Apoptosis of Cultured PC12 Cells

We examined what effects are exerted by expression of the bcl-2 gene and by treatment with nerve growth factor (NGF) on the intensity of apoptosis in cultured pheochromocytoma cells (PC12 cells). Half of these cells were transduced with the bcl-2 gene using lentiviral plasmids, and the respective two groups were denoted as bcl-2-PC12 and control (c) PC12. Then the cells were incubated in a serum-free medium in six different modes. One group of c-PC12 cells was incubated in this medium with no additional agents added, another group was incubated with 1.0 mM H₂O₂ , and the third group was incubated with both 1 mM H₂O₂ and 20 ng/ml NGF (groups 1-3). Cells of the another triad were incubated under the same conditions, respectively, but these were bcl-2-PC12 cells (groups 4-6). The apoptosis rate in each group after 1-h-long incubation was measured using a flow cytometry method. A bicinchoninic acid (BCA) technique was used for estimation of expression of Bcl-2 protein in the cultures. As was observed, the action of H₂O₂ significantly increased the apoptosis rate in both c-PC12 and bcl-2-PC12 samplings, while simultaneous action of NGF considerably attenuated such increases. At the same time, values of the apoptosis rate for bcl-2-PC12 cells were much smaller than the respective values for c-PC12 cells under all the three modes of incubation. In H₂O₂ -treated cultures, the amount of Bcl-2 protein dropped, while the treatment with NGF counteracted such shifts. The content of this protein in the bcl-2-PC12 groups was much higher than in the c-PC12 groups. Thus, transduction with the bcl-2 gene significantly inhibits apoptosis in cultured PC12 cells, and a combined influence of expression of this gene and treatment with NGF produces a synergistic effect.Ми досліджували впливи експресії гена bcl-2 та дії нервового фактора росту (NGF) на інтенсивність апоптозу культивованих клітин феохромоцитоми (PC12). У половину таких клітин був трансдукований ген bcl-2; відповідні дві групи зразків були позначені як bcl-2-PC12 та контрольні (с-PC12). Потім шість груп клітин інкубували в безсироватковому середовищі в різних умовах. Перша група клітин с-PC12 інкубувалася без дії будь-яких додаткових агентів, друга група – з додаванням 1 мМ H₂O₂ , а третя – в присутності як 1 мМ H₂O₂ , так і 20 нг/мл NGF. Клітини трьох інших груп (4–6) інкубували в тих самих умовах, але це були клітини bcl-2-PC12. Ступінь апоптозу в кожній групі після одногодинної інкубації вимірювали з використанням методу флоуцитометрії. Методику з використанням біцинхонінової кислоти застосовували для оцінки експресії білка Bcl-2 в культурах. Як було виявлено, дія H₂O₂ істотно збільшувала ступінь апоптозу в зразках як c-PC12, так і bcl-2-PC12, але одночасна дія NGF помітно зменшувала таке зростання. В той же час інтенсивності апоптозу клітин bcl-2-PC12 були значно меншими, ніж відповідні значення у клітин c-PC12 при всіх трьох режимах інкубації. В культурах, підданих впливу H₂O₂ , кількість протеїну Bcl-2 була зменшеною, тоді як вплив NGF протидіяв таким зрушенням. Вміст згаданого протеїну в групах bcl-2-PC12 був значно вищим, ніж у групах c-PC12. Отже, трансдукція гена bcl2 істотно гальмує апоптоз культивованих клітин PC12, а комбінований вплив експресії цього гена та аплікації NGF забезпечує сінергічні ефекти

Chemical abundances of 1111 FGK stars from the HARPS GTO planet search program.Galactic stellar populations and planets

We performed a uniform and detailed abundance analysis of 12 refractory elements (Na, Mg, Al, Si, Ca, Ti, Cr, Ni, Co, Sc, Mn and V) for a sample of 1111 FGK dwarf stars from the HARPS GTO planet search program. 109 of these stars are known to harbour giant planetary companions and 26 stars are hosting exclusively Neptunians and super-Earths. The main goals of this paper are i) to investigate whether there are any differences between the elemental abundance trends for stars of different stellar populations; ii) to characterise the planet host and non-host samples in term of their [X/H]. The extensive study of this sample, focused on the abundance differences between stars with and without planets will be presented in a parallel paper. The equivalent widths of spectral lines are automatically measured from HARPS spectra with the ARES code. The abundances of the chemical elements are determined using a LTE abundance analysis relative to the Sun, with the 2010 revised version of the spectral synthesis code MOOG and a grid of Kurucz ATLAS9 atmospheres. To separate the Galactic stellar populations we applied both a purely kinematical approach and a chemical method. We found that the chemically separated (based on the Mg, Si, and Ti abundances) thin and thick discs are also chemically disjunct for Al, Sc, Co and Ca. Some bifurcation might also exist for Na, V, Ni, and Mn, but there is no clear boundary of their [X/Fe] ratios. We confirm that an overabundance in giant-planet host stars is clear for all the studied elements.We also confirm that stars hosting only Neptunian-like planets may be easier to detect around stars with similar metallicities as non-planet hosts, although for some elements (particulary alpha-elements) the lower limit of [X/H] are very abrupt.Comment: 14 pages, 12 figures, 6 tables. accepted for publication in Astronomy & Astrophysic

Accelerated FoxP2 Evolution in Echolocating Bats

FOXP2 is a transcription factor implicated in the development and neural control of orofacial coordination, particularly with respect to vocalisation. Observations that orthologues show almost no variation across vertebrates yet differ by two amino acids between humans and chimpanzees have led to speculation that recent evolutionary changes might relate to the emergence of language. Echolocating bats face especially challenging sensorimotor demands, using vocal signals for orientation and often for prey capture. To determine whether mutations in the FoxP2 gene could be associated with echolocation, we sequenced FoxP2 from echolocating and non-echolocating bats as well as a range of other mammal species. We found that contrary to previous reports, FoxP2 is not highly conserved across all nonhuman mammals but is extremely diverse in echolocating bats. We detected divergent selection (a change in selective pressure) at FoxP2 between bats with contrasting sonar systems, suggesting the intriguing possibility of a role for FoxP2 in the evolution and development of echolocation. We speculate that observed accelerated evolution of FoxP2 in bats supports a previously proposed function in sensorimotor coordination

New insight into kinetics behavor of the structural formation process in Agar gelation

A time-resolved experimental study on the kinetics and relaxation of the structural formation process in gelling Agar-water solutions was carried out using our custom-built torsion resonator. The study was based on measurements of three naturally cooled solutions with agar concentrations of 0.75%, 1.0% and 2.0% w/w. It was found that the natural-cooling agar gelation process could be divided into three stages, sol stage (Stage I), gelation zone (Stage II) and gel stage (Stage III), based on the time/temperature evolutions of the structural development rate (SDR). An interesting fluctuant decaying behavior of SDR was observed in Stage II and III, indicative of a sum of multiple relaxation processes and well described by a multiple-order Gaussisn-like equation: . More interestingly, the temperature dependences of the fitted values of Wn in Stage II and Stage III were found to follow the different Arrhenius laws, with different activation energies of EaII= 39-74 KJ/mol and EaIII~7.0 KJ/mol. The two different Arrhenius-like behaviors respectively suggest that dispersions in Stage II be attributed to the relaxation of the self-assembly of agar molecules or the growth of junction zones en route to gelation, in which the formation or fission of hydrogen bonding interactions plays an important role; and that dispersions in Stage III be attributed to the relaxation dynamics of water released from various size domains close to the domain of the viscous flow of water during the syneresis process.Comment: 24 pages, 4 figures, 1 tabl

Performance evaluation on an air-cooled heat exchanger for alumina nanofluid under laminar flow

This study analyzes the characteristics of alumina (Al2O3)/water nanofluid to determine the feasibility of its application in an air-cooled heat exchanger for heat dissipation for PEMFC or electronic chip cooling. The experimental sample was Al2O3/water nanofluid produced by the direct synthesis method at three different concentrations (0.5, 1.0, and 1.5 wt.%). The experiments in this study measured the thermal conductivity and viscosity of nanofluid with weight fractions and sample temperatures (20-60°C), and then used the nanofluid in an actual air-cooled heat exchanger to assess its heat exchange capacity and pressure drop under laminar flow. Experimental results show that the nanofluid has a higher heat exchange capacity than water, and a higher concentration of nanoparticles provides an even better ratio of the heat exchange. The maximum enhanced ratio of heat exchange and pressure drop for all the experimental parameters in this study was about 39% and 5.6%, respectively. In addition to nanoparticle concentration, the temperature and mass flow rates of the working fluid can affect the enhanced ratio of heat exchange and pressure drop of nanofluid. The cross-section aspect ratio of tube in the heat exchanger is another important factor to be taken into consideration

Observation of the electromagnetic doubly OZI-suppressed decay J/ψ→ϕπ0J/\psi \rightarrow \phi \pi^{0}

Using a sample of $1.31$ billion $J/\psi$ events accumulated with the BESIII detector at the BEPCII collider, we report the observation of the decay $J/\psi \rightarrow \phi\pi^{0}$, which is the first evidence for a doubly Okubo-Zweig-Iizuka suppressed electromagnetic $J/\psi$ decay. A clear structure is observed in the $K^{+} K^{-}$ mass spectrum around 1.02 GeV/$c^2$, which can be attributed to interference between $J/\psi \rightarrow \phi\pi^{0}$ and $J/\psi \rightarrow K^{+}K^{-}\pi^{0}$ decays. Due to this interference, two possible solutions are found. The corresponding measured values of the branching fraction of $J/\psi \to \phi\pi^{0}$ are $[2.94 \pm 0.16\text{(stat.)} \pm 0.16\text{(syst.)}] \times 10^{-6}$ and $[1.24 \pm 0.33\text{(stat.)} \pm 0.30\text{(syst.)}] \times 10^{-7}$.Comment: 7 pages, 4 figures, published in Phys. Rev.