Number Of Elementary Charges Research Articles

On the Relationship between Quarks and Electrons

In this study, the relationship between the elementary masses and elementary charges of quarks and electrons is considered in connection to the strong nuclear force and the color charge. The relationship is further considered in connection with the matter-antimatter asymmetry problem, and the decay times for different particles. The results strongly suggest that the quarks can be expressed as charge equalization of the electron, and that the coincidence of the charges has no alternative way to be unified with the elementary masses. To solve these problems, a new standard model with a second group of antiparticles is proposed, and the strong nuclear force is considered as an interaction between equalized electric charges instead of being a fundamental force, which also explains its short-ranged high strength. A new periodic table of elements is proposed to unfold the overall number of elementary charges that make up the atomic nucleus of different elements.

Bipolar Charge Analyzer (BOLAR): A new aerosol instrument for bipolar charge measurements

The Bipolar Charge Analyzer (BOLAR, Dekati Ltd.) is a new commercial instrument developed to characterize bipolar charge and charge-to-mass ratio of powders and inhaled aerosols as a function of particle size. The instrument combines aerodynamic size classification with electrostatic precipitator based bipolar charge measurement. As a result bipolar charge and charge-to-mass ratios are obtained for 5 size fractions between zero and 11.6µm. In this study we present the operation concept, design and the performance characteristics of the BOLAR. The instrument was calibrated using monodisperse particles in laboratory conditions. The performance of the instrument in inhaler measurement was tested by measuring aerosol produced by a dry powder inhaler (DPI). The DPI was found to produce noticeable levels of positively and negatively charged particles. For a single size fraction the largest observed positive and negative values were +300pC and −200pC, respectively, although the net charge was close to zero. By analyzing the mass of the particles collected by the individual parts of the BOLAR the size fractioned charge-to-mass ratios were calculated for the tested inhaler. The largest values were approximately ±20pC/µg which was obtained for particles having a mean diameter of 1.8μm. The number of elementary charges per particle ranged from ±500 up to ±8000 depending on the particle size.

Multiple mechanisms underlying rectification in retinal cyclic nucleotide-gated (CNGA1) channels

In cyclic nucleotide-gated (CNGA1) channels, in the presence of symmetrical ionic conditions, current–voltage (I-V) relationship depends, in a complex way, on the radius of permeating ion. It has been suggested that both the pore and S4 helix contribute to the observed rectification. In the present manuscript, using tail and gating current measurements from homotetrameric CNGA1 channels expressed in Xenopus oocytes, we clarify and quantify the role of the pore and of the S4 helix. We show that in symmetrical Rb+ and Cs+ single-channel current rectification dominates macroscopic currents while voltage-dependent gating becomes larger in symmetrical ethylammonium and dimethylammonium, where the open probability strongly depends on voltage. Isochronal tail currents analysis in dimethylammonium shows that at least two voltage-dependent transitions underlie the observed rectification. Only the first voltage-dependent transition is sensible to mutation of charge residues in the S4 helix. Moreover, analysis of tail and gating currents indicates that the number of elementary charges per channel moving across the membrane is less than 2, when they are about 12 in K+ channels. These results indicate the existence of distinct mechanisms underlying rectification in CNG channels. A restricted motion of the S4 helix together with an inefficient coupling to the channel gate render CNGA1 channels poorly sensitive to voltage in the presence of physiological Na+ and K+.

Approximate relationship between voltage and mobility for Brownian particles in cylindrical DMAs

This work presents the results of a theoretical investigation aimed at the determination of the relationship between applied voltage V and mobility Z for highly diffusive particles classified in a concentric cylindrical differential mobility analyzer (DMA). Based on knowledge of the mean of the first passage time probability distribution, the expression V/Vnd=1−2πkTLZ/peQsh has been obtained (Vnd=classification voltage for non-diffusing particles; k=Boltzmann's constant; T=absolute temperature; L=DMA length; p=number of elementary charges on the particle; e=electron's charge; Qsh=sheath air flow rate). Numerical simulations of particle trajectories have shown that the above expression is only approximate and that the last term, accounting for the effect of diffusion, has to be multiplied by a geometrical factor which is approximately given by the fitting expression 2.49ln−0.66(R2/R1), where R1 and R2 are the inner and outer electrode radii, respectively. The V/Vnd ratio departs from one only in extreme cases, namely, classification of particles with very high mobility in a quite long DMA operated at relatively low flow rates. For other situations the difference between V and Vnd is negligible.

Detection of Elementary Charges on Colloidal Particles

We have succeeded in determining the charge of individual colloidal particles with resolution higher than the elementary charge. The number of elementary charges on a particle is obtained from the analysis of optical tracking data of weakly charged silica spheres in an electric field in a nonpolar medium. The analysis also yields an accurate value of the particle size. Measurement of the charge as a function of time reveals events in which the particle loses or gains an elementary charge due to ionization or recombination processes at the surface.

Control of nanoparticle charge via condensation magnification

Previously, we reported a method for preparing highly charged nanoparticles via condensation magnification [Suh, J., Han, B., Kim, D. S., & Choi, M. (2005). A method for enhanced charging of nanoparticles via condensation magnification. Journal of Aerosol Science, 36, 1183–1193]. In the present work, we attempt to control the charge level of nanoparticles by varying the droplet size in the condensation magnification method. We also investigate whether both metallic and dielectric nanoparticles could be highly charged and their charge level can be controlled. Three different cases of 12 and 25 nm gold particles and 22 nm polystyrene polymer (PSP) particles were examined and for all three cases, the number of elementary charges could be successfully controlled by varying droplet sizes. The maximum charges of 12 and 25 nm gold nanoparticles were about 15 and 57 units, respectively, and that of 22 nm polystyrene polymer (PSP) particles was 43 units. Surface electric field strength corresponding to these maximum charges was found to be approximately independent of particle sizes indicating that ion evaporation model could be valid in our charging process.

Measurements of particle size distribution and average particle charge in operating a hard disk drive

As the flying height of a slider in a hard disk drive decreases, the slider and disk are more likely to come into contact and generate contamination particles. Since particle contamination can cause serious problems including thermal asperity, it must be prevented to increase storage capacity. In this work, first we measured the size distribution of the particles according to the disk rotational speed by using an APS (aerodynamic particle sizer) and DMA (differential mobility analyzer)–CPC (condensation particle counter). The results showed that mainly submicron particles were generated and particle generation rate increased as the disk rotational speed increased. Then, the electrical current due to particle charge was measured by a Faraday cup. Calculated from experimental data, the average number of elementary charges per particle was from 1.9 to 5.2, and it decreased as the disk rotational speed increased. Finally, SEM (scanning electron microscopy) images of particles were obtained by using a particle sampler designed in our laboratory. With these images, we were able to verify the relation between particle generation rate and disk rotational speed.

Effect of coagulation on the asymmetric charging of aerosols

The asymmetric charge distribution on submicron aerosols has been examined by solving the ion–aerosol balance equations including the effects of both the ion–aerosol attachment mechanism and the coagulation of charged aerosols. Our results for the case of asymmetric charging show a decrease in the charging asymmetry as compared to Hoppel and Frick's [Aerosol Sci. Technol. 5 (1986) 1] results where the effect of coagulation is not included. Further, the results show an excess of negative aerosols when the number of elementary charges on the aerosols p≤3 and an excess of positive aerosols when p≥4. As in the case of symmetric charging, in asymmetric charging, the particle charge distribution is found to depend on the aerosol concentration and the rate of ionization. The contribution of the coagulation process becomes significant when the aerosol concentration exceeds ∼10 5 particles cm −3. Moreover, the charging asymmetry increases with increasing aerosol concentrations but decreases with the increasing ionization rate.

Charge Distribution of Submicron Particles Charged by Spray Electrification or Corona Discharge

This paper reports on the charge distribution measurements of submicron particles for three different charging mechanisms, which are spray electrification, bipolar ionization and corona discharge process, respectively. The number of elementary charges per particle was investigated by classifying and counting of a discrete mobility class. Charge distribution measurements were performed with NaCl particles generated from a collision atomizer for 0.01, 0.1, 1% NaCl solutions. Experimental results show than charge level of atomized NaCl particles is high and decreases with increasing the dissolved ion concentration. The charge level of the atomized NaCl particles can be reduced to that o Boltzmann equilibrium conditions by the bipolar ionization(Po(sup)210 bipolar ionizer). The charge level on NaCl particles passing through the corona discharge reactor is much higher than those of atomized or bipolar ionized NaCl particles. The evaluation of these measurements results in charge distribution of the submicron particles.

Characterization of the Charge Distribution of Airborne Dust in Canadian Uranium and Non-Uranium Mines

The levels of charge found on airborne dust from various mining and milling operations were measured. More specifically, uranium and non-uranium operations were surveyed, and definite differences in charge distribution were observed. Charge distributions in both types of mines were noted to be symmetrical (net neutral), and while data from non-uranium mines and mills showed good agreement with data gathered by other investigators, uranium mine and mill results seemed to be abnormally low for the types of operations involved. For example, the number of elementary charges associated with 7.5-µm dust was 24 for uranium mines compared with 197 for non-uranium mines at underground primary crusher operations. Similar differences were noted at surface secondary crushing plants where the numbers of charges measured were 15 and 71, respectively, for uranium and non-uranium mills, again for 7.5-µm dust. In an effort to explain these differences, the effects of the level of mechanization, relative humidity, and the ...

The scavenging of particles by electrified drops: radar echo intensification following lightning

A series of laboratory experiments were performed in an effort to improve our understanding of the physics of the echo-intensification phenomenon, in which the radar reflectivity of a region of a thundercloud increases rapidly immediately following the occurrence of lightning within it. Measurements were made of the charges, q, deposited on falling water drops when they engage in direct interactions with positive corona streamers in a uniform electric field, E, just above the limit for propagation, E0. As the drop radius increased from 12 to 950/μm, q increased from about 10−13 to about 10−10C; and q increased as E was raised above E0. These measurements yielded an estimate of 30μm and 108, respectively, for the radius of, and the number of elementary charges contained in, the tip of a propagating streamer at a pressure of one atmosphere. The collection efficiencies of drops in the radius range 40 to 120 μm carrying charges appropriate to the direct interaction process, for uncharged droplets of radius around 12 μm, were found to be about four times the non-electrical values. It was concluded that this enhancement in collection resulted largely from dipole rather than coulomb forces. A simple analysis indicates that reported echo-intensification observations cannot be explained in terms of these enhanced collection efficiencies, but could possibly be a consequence of the greatly enhanced velocities (and hence growth rates) of drops of radius ∼ 100 μm highly charged by direct interaction with corona streamers in the intense electric fields of a thundercloud.

The scavenging of particles by electrified drops: Radar echo intensification following lightning

AbstractA series of laboratory experiments were performed in an effort to improve our understanding of the physics of the echo‐intensification phenomenon, in which the radar reflectivity of a region of a thundercloud increases rapidly immediately following the occurrence of lightning within it. Measurements were made of the charges, q, deposited on falling water drops when they engage in direct interactions with positive corona streamers in a uniform electric field, E, just above the limit for propagation, E0. As the drop radius increased from 12 to 950/μm, q increased from about 10−13 to about 10−10C; and q increased as E was raised above E0. These measurements yielded an estimate of 30μm and 108, respectively, for the radius of, and the number of elementary charges contained in, the tip of a propagating streamer at a pressure of one atmosphere.The collection efficiencies of drops in the radius range 40 to 120 μm carrying charges appropriate to the direct interaction process, for uncharged droplets of radius around 12 μm, were found to be about four times the non‐electrical values. It was concluded that this enhancement in collection resulted largely from dipole rather than coulomb forces. A simple analysis indicates that reported echo‐intensification observations cannot be explained in terms of these enhanced collection efficiencies, but could possibly be a consequence of the greatly enhanced velocities (and hence growth rates) of drops of radius ∼ 100 μm highly charged by direct interaction with corona streamers in the intense electric fields of a thundercloud.

A New Method of ADC for Improving Resolution

A new method of ADC which reduces noise by the measurement of the signal area is described. The area is evaluated by an integrator which compares it to a number of elementary charges, this number being the digital value proportional to the energy of the detected particle. Further improvements of the method are indicated.