Strong Negative Electric Field Research Articles

Molecular simulations of lysozyme adsorption on an electrically responsive mixed self-assembled monolayer

Lysozyme adsorption on electrically responsive carboxyl/hydroxyl (SC10COOH/SC3OH) self-assembled monolayer (SAM) was investigated by molecular simulation. Results show that applied positive electric fields help to increase the surface hydrophilicity by aligning the chains parallel to the surface normal and exposing their carboxyl groups, whereas applied negative electric fields increase the surface hydrophobicity by bending the SC10COOH chains to expose their alkyl moieties. Accordingly, lysozyme behavior on the SAM was affected. Protein-surface interactions are significantly weakened by a strong negative electric field because of the decreased electrostatic interactions. However, the applied positive electric fields do not strengthen the protein-surface interactions probably because the hydrogen bonds formed within the surface chains, the binding of water molecules to form a water layer and the competitive adsorption from counterions can all decrease the interactions of the SAM with lysozyme. Adsorbed orientations of lysozyme could be regulated among “back-on”, “bottom-leaning” and “side-on” by applying a strong positive electric field or negative electric fields. Analysis of the conformational changes of lysozyme reveals that there is no direct relation between the protein deformation and the strength or direction of electric fields. This work may help to design and fabricate efficient electrically responsive surface in experiments for biotechnological applications.

HCFL Lamp Only Lights Up under Coexistence of Cathode and Anode in Ar Gas Space for Half Cycle of AC Driving Circuit

Vacuum space between Ar atoms in unlighted HCFL lamps is an electric insulator, because vacuum fills up with strong negative electric field from orbital electrons in 3p6 electron shell of Ar atoms. Vacuum space in lighted FL lamps changes to the neutral vacuum that provides a superconductive vacuum for moving electrons at above room temperature. The complications of lighting mechanisms of HCFL lamps for more than 80 years have clearly solved with coexistence of disparate external and internal electric circuits for each half cycle. External electric circuit acts as two roles. One helps for formation of internal electric circuit in Ar gas space by electric field. Other picks up induced voltages from capacitor CFL. HCFL lamp only lights up with moving electrons in internal DC driving circuit. Electrons in HCFL lamp only move from cathode to anode, which respectively have negative and positive potentials against grand (V = 0), and which are formed with volumes of heated corona light (4G) at around W-filament metal electrodes with a help of heated BaO particles. The HCFL lamp that emits thermoelectrons is a false story. Here we have totally revised the fundamentals of the lighting mechanism of the established HCFL lamps for last 80 years.

Corona discharges from a windmill and its lightning protection tower in winter thunderstorms

AbstractThis paper presents lightning mapping array (LMA) observations of corona discharges from a windmill and its lightning protection tower in winter thunderstorms in Japan. Corona discharges from the windmill, called windmill coronas, and those from the tower, called tower coronas, are distinctly different. Windmill coronas occur with periodic bursts, generally radiate larger power, and possibly develop to higher altitudes than tower coronas do. A strong negative electric field is necessary for the frequent production of tower coronas but is not apparently related with windmill coronas. These differences are due to the periodic rotation of the windmill and the moving blades which can escape space charges produced by corona discharges and sustain a large local electric field. The production period of windmill coronas is related with the rotation period of the windmill. Surprisingly, for one rotation of the windmill, only two out of the three blades produce detectable discharges and source powers of discharges from these two blades are different. The reason for this phenomenon is still unclear. For tower coronas, the source rate can get very high only when there is a strong negative electric field, and the source power can get very high only when the source rate is very low. The relationship between corona discharges and lightning flashes is investigated. There is no direct evidence that corona discharges can increase the chance of upward leader initiation, but nearby lightning flashes can increase the source rate of corona discharges right after the flashes. The peak of the source height distribution of corona discharges is about 100 m higher than the top of the windmill and the top of the tower. Possible reasons for this result are discussed.

Electro-osmotic flow in nanochannels with voltage-controlled polyelectrolyte brushes: Dependence on grafting density and normal electric field

Molecular dynamics simulations were performed for electro-osmotic flow (EOF) confined in a polyelectrolyte- grafted nanochannel under variable grafting density and nor- mal electric field. With decreasing the value of the normal elec- tric field, the brush undergoes a collapse transition, and the ion distribution is changed significantly. The brush thickness increases on increasing the grafting density at positive and weak negative electric fields, whereas a reduced brush thick- ness is observed at strong negative electric field. Our results further reveal that the flow velocity is not only dependent on conformational transition of the brush but also related to the cation and anion distributions. At low grafting density, the EOF is almost completely quenched at high electric field strength due to strong surface friction between ions and walls. For the case of very dense grafting, the flow velocity is influenced weakly within the brush when varying the grafting density. Additionally, a bidirectional flow occurs at an intermediate electric field. The investigation on fluid flux indicates that the fluid flux is insensitive to the grafting density, when the normal electric field is removed. For nonzero normal electric fields, a significant change in the fluid flux is observed at low grafting densities. V C 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 50: 805-811, 2012

Crack energy density in arbitrary direction for piezoelectrics and its characteristic features in electromechanical mixed mode crack

The concepts of crack energy density (CED) and its derivatives in arbitrary direction were established for piezoelectric material and, keeping their application to mixed mode fracture in mind, the characteristic features of them as fracture parameters were investigated based on the approximate equations for CED and its derivatives. That is, CED and its derivatives in arbitrary direction are defined first and separation into their each mode contribution is made. Subsequently, path independent integral expressions of them are derived, and then using them, approximate equations of each mode contribution of CED are obtained concretely for the case where linear singular solution is known. The resulting equations are then used to investigate the effects of electric field and electrical boundary condition on CED and its derivatives. An infinite piezoelectric plane with a crack inclined with respect to the poling direction is considered as a numerical example. Mode I contribution of mechanical CED is mainly employed as a possible fracture parameter for the study and it was shown that applied electric field significantly influences on fracture parameters especially for the impermeable crack perpendicular to the poling direction. The effect of electric field has the tendency to decrease as crack inclination angle increases. It was also found that, even for the impermeable crack perpendicular to the poling direction, crack propagation could be deviated from self-similar direction under a strong negative electric field, and this fact is qualitatively consistent with an existing experimental observation. For the ideally sharp crack with no width, impermeable and Hao and Shen type boundary conditions are admissible showing qualitative agreement with experimental results, but exact boundary condition is not suitable and finally consistent with permeable boundary condition.

Theory of energetic ion transport induced by waves of ion cyclotron range of frequencies in a tokamak plasma

A theoretical description of radial energetic-ion transport induced by electromagnetic waves of ion cyclotron range of frequencies (ICRF) is presented in a tokamak with general flux surface geometry. A known form of quasilinear operator is used to represent the ICRF wave-induced particle scattering in velocity space. The theory is applied to both nonflowing and flowing groups of energetic ions, represented by alpha particles born from deuterium–tritium reactions, and energetic ions born from unbalanced neutral beam injection, respectively. It is found that ICRF waves with reasonable power can be used for manipulation of the local radial energetic ion flow at practical level. A simple integral representation of the radial fluxes is suggested for implementation into a transport code. A brief discussion on the possibility of the strong negative electric field generation by ICRH at the plasma edge is also presented.