The Wavelength Shifting and Temperature Athermalization of Fiber Bragg Grating

The wavelength shifting properties and the temperature athermalization technology of fiber Bragg grating (FBG) were studied in this paper, and then two different athermalization methods were introduced. The research shows that FBG with athermalization by applying the substrate with negative coefficient of thermal expansion is effective and can be used in many fields.

Isothermal and athermal martensitic transformations of ceria cerla doped zilrconian

Martensitic transformation behavior was studied for zirconia containing 4%～10% CeO2 (in mole fraction) by using a dilatometric method. The Ms (Martensite start temperature) decreased near linearly with increasing CeO2. Different transformation modes were observed depending on the composition and cooling rate. ZrO2 containing 6% CeO2 showed isothermal transformation behavior, whereas ZrO2 containing 9% and 10% CeO2 showed athermal transformation behavior. However, ZrO2 containing 8% CeO2 showed either isothermal or athermal transformations behavior depending on the cooling rate. A TTT (Time-Temperature-Transformation) diagram was proposed for ZrO2 containing 8% CeO2.

Connections between the Specific Absorption Rate and the Local Temperature

The specific absorption rate (SAR) characterises the energy intake from outside energy sources. Dominantly, the dosing of electromagnetic radiation uses the SAR, defining the absorbed power in unit mass, measured in W/kg. Ionisation radiation creates a certain distortion in the DNA, which is the goal of radiation in oncology. The dose in this case counts the time duration of the actual SAR, and uses the absorbed energy instead of the absorbed power, measured by Gy (=J/kg). The ionising rate is the desired result, and the developed temperature is only an unwanted side effect. In the case of non-ionising radiation, the same characterisation is used for completely opposite goals. There, the direct interest is the temperature increase, and the excitation processes other than temperature increasing energy consumptions are neglected. Our objective in this work is to clarify the connections of SAR and developed temperature, and discussing the actual debates about non-ther-mal energy absorption.

EFFECT OF MAGNETIC FIELD ON MARTENSITIC TRANSFORMATION IN Fe-21Ni-4Mn ALLOY

The pulsed magnetic field induced martensitic transformation with isothermal and athermalkinetics in Fe-2Ni-4Mn(wt-%)alloy has been studied by means of magnetizationmeasurements,optical microscopy and thermodymical analyses.It is shown that there exits acritical magnetic intensity for induing martensitic transformation at a given temperatureabove Ms.The critical magnetic field increases linearly with increasing ΔT= T-M_S.Themagnetic field strongly promotes the athermal martensitic transforamtion and restrains theisothermal one.The entropy change ΔS for athermal transformation at Ms is 4.13 J/mol·K.The effect of magnetic field on martensitic transformation in Fe-21Ni-4Mn alloy is main-ly due to Zeeman effect.Lath,plate and butterfly martensities were observed under magneticfield.

The effect of low frequency electromagnetic field on plasma β-endorphin in human brain

The effect of electromagnetic field on plasma β endorphin in 30 patients with migraine were studied in the experiment. All subjects received a 20 minute repetitive transcranial magnetic stimulation (Frequency 10Hz, Average intensity 8mT) per time, and the total experiment lasted 20 times. Before and after the experiment, the EEG and plasma β endorphin were tested. The results show that the level of plasma β endorphin in patients blood increased significantly from (73.486±26.002)mg/ml to (116.934±67.592)mg/ml (p<0.01), and the EEG average magnitude of the migraine patients were improved obviously from 41.77μV to 47.42μV.

Experimental study and mechanism analysis on bioeffects by nanosecond electromagnetic pulses

The athermal bioeffects caused by nanosecond electromagnetic pulses with body cells was studied by using a broad band transverse EM-wave cell (BTEM CELL). The experimental system and preliminary mechanism analysis were presented.

Effect of electropulsing treatment on static recrystallization behavior of cold-rolled magnesium alloy ZK60 with different reductions

Effect of electropulsing treatment(EPT) on recrystallization behavior of cold-rolled Mg alloy ZK60 strips was investigated. It was found that EPT significantly improved nucleation rate and migration ability of grain boundaries, leading to accelerated recrystallization of the deformed metals at relatively low temperature. After the recrystallization induced by EPT, the average grain size of 20% rolling reduction samples decreased from 113 um to around 10 um, meanwhile the typical basal-type texture of the coldrolled sample was weakened. EPT was normally accompanied with a thermal and an athermal effects. The athermal effect played a dominated role in increasing nucleation rate, while the thermal effect promoted grain growth. A fewer recrystallized grains originated along the grain boundaries in the 10% reduction samples, while most of the recrystallization took place inside the twins in the 20% reduction samples.

Study of an athermal infrared dual band optical system design containing harmonic diffractive element

A harmonic diffractive element (HDE) is first successfully introduced to the athermal system of infrared dual band in this paper. In this system, there are only three lens and two materials, silicon and germanium. When the temperature ranges from 70℃ to 100℃ in the dual band, it can simultaneously accomplish the rectification of the longitudinal aberration in the big field of view, as well as the wave front aberration less than 1/4 wavelength. Modulation transfer function of dual band approaches or attains the diffraction limit. The calculation results show that the spec-tral properties of the HDE are between refractive and dif-fractive elements, so we can design a simple dual-band and athermal optical system by selecting the thickness and cen-tral wavelength of the HDE exactly. Compared with a con-ventional refractive optical system, this system not only re-duces the demand for high technical levels, but also has a compact structure, few elements, a high transmittance better aberrations performances and athermal character. At the same time, the use of the HDE also offers a new element for the infrared optics design.