Hump Phenomenon Research Articles

Oxygen reduction mechanism on copper in a 0.5 M H 2SO 4

The mechanism of the oxygen reduction reaction (ORR) in a naturally aerated stagnant 0.5 M H 2SO 4 was studied using electrochemical methods. The cathodic polarization curve showed three different regions; electrochemical impedance spectroscopy (EIS) measurement was used accordingly. The EIS data were analyzed, and the mechanism for the ORR was proposed consequently. The three regions include a limiting current density region with the main transfer of 4e − controlled by diffusion (−0.50 V < E < −0.40 V), a combined kinetic-diffusion region (−0.40 V < E < −0.20 V) with an additional 2e − transfer due to the adsorption of the anions, and a hump phenomenon region (−0.20 V < E < −0.05 V), in which the chemical redox between the anodic intermediate Cu ( I ) ads * and the cathodic intermediate ( H O x ) ads * , together with the electrochemical reaction, synergistically results in the acceleration of the ORR. Therefore, a coupled electrochemical/chemical process (the EC mechanism) in the hump phenomenon region was proposed, and a good agreement was found between the experimental and fitted results. The EC mechanism was confirmed by the deaerated experiments.

Simulation of the electrical characteristics of MOS capacitors on strained‐silicon substrates

AbstractIn this work, we analyze the electrical characteristics of MOS capacitors fabricated on strained silicon substrates using the commercial software Taurus/Synopsis. The effect of various parameters such as Germanium concentration in the Si1–xGex virtual substrate, thickness of the strained‐Silicon layer, oxide thickness, fixed charge and interface trapped charge on capacitance – voltage characteristics is examined. Experimental data are compared with simulation results. A strong influence of the s‐Si/SiGe heterostructure and its proximity to the s‐Si/SiO2 on the electrical characteristics of the system exists. Oxide charge inserted into simulation in order to fit experimental data shows an increase of charge with decreasing s‐Si thickness. The effect of interface traps on simulated C‐V characteristics is identical when traps are situated in the s‐Si/SiO2 or the s‐Si/SiGe interface. When increasing the thermal budget by increasing the post oxidation annealing time, the decrease of the hump phenomenon on the C‐V curves can be attributed to the Germanium diffusion, according to simulation. (© 2008 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

Hump phenomenon on resistivity–temperature curve in liquid Bi, Sb and their alloys

The electrical resistivities of liquid Bi, Sb, and some of their alloys Pb–Bi, Pb–Sb have been investigated as a function of temperature, and the effect of heating-rate on the turning points of liquid Bi has also been investigated. Obvious and interesting hump phenomena are observed on resistivity–temperature curves of liquid Bi, Sb, and Pb–Bi, Pb–Sb alloys on heating at the temperature far above their liquidus. Moreover, the transition temperature of liquid Bi increases with heating-rate increasing, which shows that this kind of transition is in accordance with kinetic characteristics. However, comparing the heating curve with the cooling one, we found that the anomalous hump phenomenon is irreversible in liquid Bi, Sb, and Pb–Bi, Pb–Sb alloys.

Trough and hump phenomenon in a kind of random system

A kind of random system applied simultaneously by the polarizing electric field and microwave field was investigated. The trough and hump phenomenon occurs simultaneously in the transmission spectra at frequency range of 8–12 GHz while microwave scanning the samples. The solid/fluid complex fluid samples are composed of BaTiO 3/silicon oil and microcapsule composite particle/silicon oil. It is seen that the troughs and humps are very similar with photonic band gaps and left-handed metamaterial transmission peaks, which respectively appear in the photonic crystal and left-handed metamaterial. Moreover, the high of troughs and humps also exhibit adjustable characteristics with respect to the external electric field. We think that the trough and hump phenomenon in random system may be originated from the interactions between local oscillation of systems and microwaves field.

Characterization of Low-Temperature Stress Hump in Relation to Phase Formation Sequence of Nickel Silicide

The stress hump phenomenon observed at a low temperature of approximately 140°C during in situ stress-temperature measurement of sputtered Ni thin film on a (001) Si substrate has been investigated. We found that the stress hump was not related to the formation of NiSi2, but originated from the thickening of an amorphous Ni–Si intermixing layer in the temperature range of 100–140°C followed by the formation of the Ni2Si phase at temperatures above 140°C.

H 2 and NH 3 Plasma Passivation on Poly-Si TFTs with Bottom-Sub-Gate Induced Electrical Junctions

The effects of and plasma passivation on the characteristics of poly-Si thin-film transistors (TFTs) with source/drain extensions induced by a bottom sub-gate were studied. Our results show that although significant improvements in device performance can be obtained by either passivation method, the -plasma-treatment appears to be more effective in reducing the off-state leakage, subthreshold swing, and in improving mobility compared to plasma passivation. Furthermore, plasma treatment is also found to be more effective in reducing the anomalous subthreshold hump phenomenon observed in nonplasma-treated short-channel devices. Detailed analysis suggests that all these improvements can be explained by the more effective passivation of traps distributed in both the front and back sides of the channel by plasma treatment. © 2003 The Electrochemical Society. All rights reserved.

Dependences of Structural Parameters on the Characteristics of Poly-Si Thin-Film Transistors after Plasma Passivation

AbstractThe effects of NH3 and H2 plasma passivation on the characteristics of poly-Si thin-film transistors with source/drain extensions induced by a bottom sub-gate were studied. Our results show that significant improvements in device performance can be obtained by both passivation methods. Moreover, NH3-plasma-treatment appears to be more effective in reducing the off-state leakage, subthreshold swing, compared to H2 plasma passivation. NH3 plasma treatment is also found to be more effective in reducing the anomalous subthrehold hump phenomenon observed in non-plasma-treated short-channel devices. Detailed analysis suggests that all these improvements can be explained by the more effective passivation of the traps distributed in both the front and back sides of the channel by NH3 plasma treatment.

Anomalous Subthreshold Characteristics of Shallow Trench-Isolated Submicron NMOSFET with Capped p-TEOS/SiN

In sub-l/4 NMOSFET with STI (Shallow Trench Isolation), the anomalous hump phenomenon of subthreshold region, due to capped p-TEOS/SiN induced defect, is reported. The hump effect was significantly observed as channel length is reduced, which is completely different from previous reports. Channel boron dopant redistribution due to the defect should be considered to improve hump characteristics besides considerations of STI comer and recess. 130

Gate-Oxide-Integrity Characteristics of Vacancy-rich Wafer Compared with Crystal-Originated-Pits-free Wafer as a Function of Oxide Thickness

The dielectric breakdown of oxides with various thickness between 5–70 nm on Czochralski (CZ)-grown silicon wafer had been investigated. To observe the effects of crystal-originated-particle (COP), vacancy-rich wafers and COP-free wafers were compared. In breakdown voltage (BV) measurement, breakdown fractions of vacancy-rich wafers were increased with the increase of oxide thickness (tOX) and showed a maximum value at the tOX range of 10–20 nm. On the other hand, COP-free wafers showed few breakdowns over all the range of tOX. Furthermore, time dependent dielectric breakdown (TDDB) of the vacancy-rich wafers showed higher extrinsic breakdowns than that of the COP-free wafers in the tOX below 20 nm. For the intrinsic breakdown, two groups showed the same charge-to-breakdown (QBD) along the strength of injection current over all the range of tOX. Especially, only in case of vacancy-rich wafer, abnormal increase of current, i.e., hump phenomena, was observed in the range of electric field below the Fowler-Nordheim (F-N) tunneling.

Manometric Components of the Lower Esophageal Double Hump

Background/Aims: The lower esophageal sphincter manometry of patients with hiatal hernia often displays a double hump configuration. It seems that this is due to gastric herniation above the high-pressure zone of the crura. This study examines this manometric phenomenon in patients with hiatal hernia and relates it to the lower esophageal antireflux barrier. Methods: Manometric and 24-hour pH studies of 68 consecutive patients with suspected gastroesophageal reflux disease were analyzed to obtain information regarding the double hump and acid reflux. Results: The findings of a manometric double hump correlated well with the presence of a hiatal hernia of >5 cm. The overall length of the sphincter complex was greater in patients with a double hump, but the length below the respiratory inversion point was constant. Resting pressures at the respiratory inversion point were significantly lower than those measured at either high-pressure zone. The location of the respiratory inversion point was seen most commonly at the superior margin of the distal high-pressure zone. Double hump patients with a negative acid reflux score were found to have higher pressures in the distal high-pressure zone than those patients with acid reflux. Conclusions: The two high-pressure zones comprising the manometric double hump represent the crural and muscular components of the lower esophageal sphincter. Descriptive information regarding the double hump phenomenon is given, and the importance of the crural component of the lower esophageal sphincter in preventing acid reflux is stressed.

Analytical subthreshold current hump model for deep-submicron shallow-trench-isolated CMOS devices

This paper reports an analytical subthreshold current hump model for deep-submicron shallow-trench-isolated CMOS devices. As verified by the experimental data, this subthreshold current hump model can provide a prediction of the back gate bias related subthreshold current hump phenomenon. According to the analytical model, with a more heavily doped substrate, the current hump phenomenon occurs at a more negative back gate bias.

Torque Amplification Phenomenon in Viscous Couplings. Effects of Camber of Inner Disk Blade.

Viscous couplings, which are mainly used in the power train of four-wheel-drive vehicles, normally operate in the viscous mode, where torque is transmitted by viscous shearing force between sets of disks alternately coupled to the input and output. Under an extreme condition, in which relative speed between the disks is largely increased, two disks come into contact with each other, resulting in a torque amplification called the hump mode. Although some theoretical and experimental studies have been made to explain the hump phenomenon, they seemed to be inadequate. In this paper the effects of the camber of the inner disk blade on the hump phenomenon were examined by means of numerical calculations. A slight camber of the disk was found to cause considerable torsional moment on the blades, resulting in an increase of the attack angle of the blade and axial thrust on the inner disk.

Superconducting and electrical properties of amorphous zirconium-transition metal binary alloys

In order to clarify the compositional effect on the superconductivity of zirconium-transition metal (M) binary amorphous alloys, the superconducting properties and electrical resistance of the alloys were examined as functions of the concentration, group number and periodicity of the M elements.T c for Zr75M25 alloys rises in the order Ru > Rh > Ir > Co > Os > Ni > Pt > Cu > Pd > Fe > Au, i.e. as the group number decreases when the periodicity belongs to the 5th period, and with decreasing M content for Zr100−X M X alloys. The highT c attained in the present work is 4.55 K for Zr80Rh20, 4.38 K for Zr75Rh25 and 4.47 K for Zr75Ru25. The temperature gradient of the upper critical magnetic field (H c2) near the transition temperature (T C) tends to increase with increasing zirconium content, and the resistive state due to the flux flow phenomena appears in a wide sweeping field. Following the sharp and large decrease of the flux flow resistance due to a peak effect, the resistance recovers sharply nearH c2. The peak effect was found to occur more distinctly for the alloys containing a magnetic element of iron or cobalt, probably because of the suppression of the pair-breaking effect due to magnetic scattering by the application of the high field nearH c2. The dominating factor for the compositional effect onT C is inferred to originate from the variation ofλ throughω for Zr100−x M X alloys and from that of λ through N(Ef) for Zr75M25 alloys. Additionally, it has been found for the Zr-M amorphous alloys that the electrical resistivityρ(T) exhibits a maximum value at temperature ranging from 2T C to 3T C, suggesting that the hump phenomenon in ρ(T) appeared through the generation of the superconducting fluctuations. The temperature coefficient of resistivity (tcr) defined by 1/R250(dR/dT) shows negative values ranging from 1.05×10−4 to 1.75×10−4 K −1 andT C was found to rise through the increase inλ with the increase in the negative value of the tcr.

The stochastic process of non-linear random vibration: Reactor-noise analysis of hump phenomena in a time domain

The stochastic process of non-linear random vibration is studied with the use of the single-mass effective-potential model. We relate first hump phenomena and excitations of lower order harmonics. An identification theory for the stochastic process of a hump event in a time domain is developed. The feasibility of the identification with the theory is demonstrated by analysing precisely the time series obtained from the numerical simulation of the model. The anomalous neutron-density oscillation resulting from core-barrel motion, as was observed in the Palisades plant, is discussed in connection with the multiple-well potential models.

A Step-Up Phenomenon of the Thyristor Control Circuit with Series RLC Elements

A circuit controlled by thyristors and having series RLC elements gives rise to a step-up phenomenon. The term step-up is defined with respect to the capacitance voltage on steady state operation, i.e., the ratio of the maximum peak value when controlled by thyristers to the peak amplitude when thyristors are short-circuited exceeds unity. The domain of possible step-up voltage is determined by the angle of displacement between current and voltage and damping factor. The step-up voltages appear across each element, i.e., not only across the capacitance, inductance, and resistance but also across the thyristors. The control characteristic has a distinctive hump phenomenon. The interrupted current results in waveform distortion, phase lag, and improved power factor. The difference of characteristics between the peak and rms values of voltages, particularly of inductance and thyristors, is large. The response time, which is evaluated by numbers of half cycles, is large when the step-up ratio becomes large. The output voltage when the circuit is used as a voltage source has a drooping characteristic.

IMPEDANCE CHARACTERISTICS OF LOADED LECHER SYSTEMS

Simple formulas are developed for the impedance of short lengths of Lecher system terminated by resistances. This impedance is most simply expressible as a multiple of the surge impedance. The variation of impedance with system length is traced and certain simple relationships are found. It is shown that any system of loads across a Lecher system is equivalent to a certain length of system terminated by a certain resistance. The formulas account for Takagishi's double hump phenomenon and this phenomenon is applied to finding the bridge shortening of an actual bridge. A method of calculating resistance from a resonance curve is derived.

On a Double Hump Phenomenon of Current through a Bridge across Parallel Lines

On a Double Hump Phenomenon of Current through a Bridge across Parallel Lines