Optimal Microwave Radiation Field Parameters for Mercury Ion Microwave Frequency Standards

We propose a method to determine the optimal power of the microwave resonance transition that simultaneously improves the signal-to-noise ratio and reduces line width based on saturation broadening theory and experiment. Saturation broadening spectra of the ground state hyperfine transition of trapped 199Hg＋ ions are measured and analyzed. The value of the optimal microwave power is obtained by using the proposed method and is verified. Rabi oscillations decay spectra of trapped 199Hg＋ ions are observed and the optimal microwave irradiation time for the maximum transition signal intensity is determined. This work will help to improve the short-term frequency stability of the mercury ion microwave frequency standard.

Low frequency noise and radiation response in the partially depleted SOI MOSFETs with ion implanted buried oxide

Low frequency noise behaviors of partially depleted silicon-on-insulator(PDSOI) n-channel metal-oxide semiconductors(MOS) transistors with and without ion implantation into the buried oxide are investigated in this paper. Owing to ion implantation-induced electron traps in the buried oxide and back interface states, back gate threshold voltage increases from44.48 V to 51.47 V and sub-threshold swing increases from 2.47 V/dec to 3.37 V/dec, while electron field effect mobility decreases from 475.44 cm2/V·s to 363.65 cm2/V·s. In addition, the magnitude of normalized low frequency noise also greatly increases, which indicates that the intrinsic electronic performances are degenerated after ion implantation processing. According to carrier number fluctuation theory, the extracted flat-band voltage noise power spectral densities in the PDSOI devices with and without ion implantation are equal to 7×10-10V2·Hz-1and 2.7×10-8V2·Hz-1, respectively, while the extracted average trap density in the buried oxide increases from 1.42×1017cm-3·e V-1to 6.16×1018cm-3·e V-1. Based on carrier mobility fluctuation theory, the extracted average Hooge’s parameter in these devices increases from 3.92×10-5to 1.34×10-2after ion implantation processing. Finally, radiation responses in the PDSOI devices are investigated. Owing to radiation-induced positive buried oxide trapped charges, back gate threshold voltage decreases with the increase of the total dose. After radiation reaches up to a total dose of 1 M·rad(si), the shifts of back gate threshold voltage in the SOI devices with and without ion implantation are-10.82 V and-31.84 V, respectively. The low frequency noise behaviors in these devices before and after radiation are also compared and discussed.

Effect of external magnetic field on the instability of THz plasma waves in nanoscale graphene field-effect transistors

The instability of plasma waves in the channel of field-effect transistors will cause the electromagnetic waves with THz frequency.Based on a self-consistent quantum hydrodynamic model,the instability of THz plasmas waves in the channel of graphene field-effect transistors has been investigated with external magnetic field and quantum effects.We analyzed the influence of weak magnetic fields,quantum effects,device size,and temperature on the instability of plasma waves under asymmetric boundary conditions numerically.The results show that the magnetic fields,quantum effects,and the thickness of the dielectric layer between the gate and the channel can increase the radiation frequency.Additionally,we observed that increase in temperature leads to a decrease in both oscillation frequency and instability increment.The numerical results and accompanying images obtained from our simulations provide support for the above conclusions.

Radiating frequency of three-loop mesoscopic LC circuit with mutual inductance obtained by IEO method

Instead of normally tackling electric circuits by virtue oI the Klrctllaott＇s theorem wnose aim is to uerlvc voxt^gc, electric current, and electric impedence, our aim in this paper is to derive the characteristic frequency of a three-loop mesoscopic LC circuit with three mutual inductances, e.g., for the radiating frequency of the three-loop LC oscillator, we adopt the invariant eigen-operator （lEO） method to realize our aim.

An investigation into natural vibrations of fluid-structure interaction systems subject to Sommerfeld radiation condition

A fluid-structure interaction system subject to Sommerfeld＇s condition is defined as a Sommerfeld system which is divided into three categories： Fluid Sommerfeld （FS） System, Solid Sommerfeld （SS） System and Fluid Solid Sommerfeld （FSS） System of which Sommerfeld conditions are imposed on a fluid boundary only, a solid boundary only and both fluid and solid boundaries, respectively. This paper follows the previous initial results claimed by simple examples to further mathematically investigate the natural vibrations of generalized Sommerfeld systems. A new parameter representing the speed of radiation wave for generalized 3-D problems with more complicated boundary conditions is introduced into the Sommerfeld condition which allows investigation of the natural vibrations of a Sommerfeld system involving both free surface and compressible waves. The mathematical demonstrations and selected examples confirm and reveal the natural behaviour of generalized Sommerfeld systems defined above. These generalized conclusions can be used in theoretical or engineering analysis of the vibrations of various Sommerfeld systems in engineering.

Effect of acoustic pulses and EHF radiation on multipotent marrow stromal cells in tissue engineering constructs

In this paper,we studied the effects of physical factors,such as,acoustic pulses of laser-induced hydrodynamics(ALIH)and extremely-high frequencies(EHF)radiation,on the formation of heterotopic bone marrow organs.A suspension of precipitated bone marrow cells from CBA mice were exposed to ALIH pulses and EHF radiation separately and in their com bination tissue engineering constructs,presenting gelatin sponges 2 by 2 by 2 mm in size containing 10^(7)nucleated bone marrow cells,were exposed to physical factors and were implanted under the renal capsules of syngeneic mice.The newly formed hematopoietic organs were examined in three and five months later after treatment.The five months old transplants were bigger in size than the three months old transplants.The number of hematopoietic cells in the rest of the groups increased during this period by a factor from 3 to 10,the increase being as high as 20-fold in the:ALH+EHF group.Maximal concentration of multipotent stromal cells(MSCs)was in the EHF+ALIH,and minimal concentration was in the ALIH+EHF.The accumulation rate of bone capsule weight was highest for the transplants of EHF+ALIH and ALIH-sponge groups during the first three months.These data showed that the combined impact of the EHF+ALIH on MSCs is the most effective for the formation of bone marrow transplantation.

Terahertz Plasma Waves in Two Dimensional Quantum Electron Gas with Electron Scattering

We investigate the Terahertz （THz） plasma waves in a two-dimensional （2D） electron gas in a nanometer field effect transistor （FET） with quantum effects, the electron scattering, the thermal motion of electrons and electron exchange-correlation. We find that, while the elec- tron scattering, the wave number along y direction and the electron exchange-correlation suppress the radiation power, but the thermal motion of electrons and the quantum effects can amplify the radiation power. The radiation frequency decreases with electron exchange-correlation con- tributions, but increases with quantum effects, motion of electrons. It is worth mentioning that radiation frequency. These properties could be plasma oscillations in nanometer FET. the wave number along y direction and thermal the electron scattering has scarce influence on the of great help to the realization of practical THz

THz plasma wave instability in field effect transistor with electron diffusion current density

The plasma wave instability in rectangle field effect transistors （FETs） is studied with electron diffusion current density by quantum hydrodynamic model in this paper. General dispersion relation including effects of electrical thermal motion, external friction associated with electron scattering effect, electron exchange-correlation contributions and quantum effects were obtained for rectangle FETs. The electron diffusion current density term is considered for further analysis in this paper. It is found that the quantum effects, the electron diffusion current density and electrical thermal motion enhance the radiation power and frequencies. But the electron exchange- correlation effects and the electron scattering effects reduce the radiation power and frequencies. Results showed that a transistor has advantages for the realization of practical terahertz sources.

Antimicrobial Properties of Copper and d-Orbital Capture

The purpose of this note is to stimulate interest in measuring and characterizing the emitted ultraviolet frequencies in antimicrobial copper materials. Antimicrobial sanitizing materials are urgently needed to limit the spread of COVID-19 virus. In the current pandemic, ultraviolet radiation is often used for sterilization. It is shown that 3 d-orbital capture in copper can result in radiation generated by copper materials. Since ultraviolet radiation is known to be effective in antimicrobial sterilization, it is logical to assume that the radiation formed by copper occurs in the ultraviolet region. Electron transitions in 3 d-orbital capture are expected to occur in this region. A description of the 3 d-orbital capture process, and the origin of the associated frequency, is given. It is shown that for Group 1B elements the strength of electron affinity in the d-orbital capture process increases with increasing Periodic Table period number, n. This is the opposite of other electron affinity properties for atoms that decrease wth an increase in n. A brief discussion of the relationship of d-orbital capture to the chemical inertness of gold is given. The same type of d-orbital capture process that occurs in antimicrobial copper occurs in high temperature superconducting cuprates.

The Instability of Terahertz Plasma Waves in Two Dimensional Gated and Ungated Quantum Electron Gas

The instability of terahertz（THz）plasma waves in two-dimensional（2D）quantum electron gas in a nanometer field effect transistor（FET）with asymmetrical boundary conditions has been investigated.We analyze THz plasma waves of two parts of the 2D quantum electron gas：gated and ungated regions.The results show that the radiation frequency and the increment（radiation power）in 2D ungated quantum electron gas are much higher than that in 2D gated quantum electron gas.The quantum effects always enhance the radiation power and enlarge the region of instability in both cases.This allows us to conclude that 2D quantum electron gas in the transistor channel is important for the emission and detection process and both gated and ungated parts take part in that process.

The high frequency acoustic radiation from the boundary layer of an axisymmetric body

The mechanism of acoustic radiation from the boundary layer of an axisymmetric body is analyzed, and its sound pressure spectrum is predicted. It is shown that the acoustic radiation results from the transition region and the turbulent boundary layer; and that the acoustic radiation from transition region is predominant at low frequencies; while the turbulent boundary layer has the decisive effect on acoustic radiation at high frequencies. The calculated values are in good agreement with the experimental data.

Chromosome aberration and micronucleus frequency in peripheral blood lymphocytes in radiation workers

Objective To investigate chromosome aberration and micronucleus frequency in peripheral blood lymphocytes in workers engaged in radiation for a long time,to reduce occupational hazard caused by ionizing radiation and to further strengthen health surveillance.Methods A total of 366 members of medical staff engaged in radiation work who underwent physical examinations in

Measurement of acoustic field radiated by low frequency power ultrasonic transducer with laser-interferometer

Based on the piezo-optic effect of medium, the refractive index of medium is the function of its density, and so it's also the function of acoustic pressure. Therefore, acoustic pressure in the optical path everywhere can be determined absolutely by laser-interferometric technique and relative distribution of pressure in the middle and far acoustic field, which can be obtained from theory or experiment respectively. Theory and experiment of measurement of pressure in acoustic field with laser-interferometer are introduced. Distribution of pressure radiated by a power ultrasonic transducer is determined by laser interferometric technique. The theoretical and experimental results are in good agreement. The receiving sensitivity of a PVDF (Polyvinylidene fluoride) transducer in free field is also calibrated absolutely due to above results and its sensitivity is -118.5 dB.