The use of fluorescence spectroscopy for plaque detection is a fast and effective way to monitor oral health. At present, there is no uniform specification for the design of the excitation light source of related products for generating fluorescence. To carry out experiments on dental plaque, the fluorescence spectra of three different bacterial species (Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, and Streptococcus mutans) were measured by hyperspectral imaging microscopy (HIM). Three critical issues were found in the experiments. One issue was the unwanted spectrum generated from a mercury line source; two four-order low-pass filters were evaluated for eliminating the unwanted spectrum and meet the experimental requirements. The second issue was the red fluorescence generated from the microscope slide made of borosilicate glass; this could affect the observation of the red fluorescence from the bacteria; quartz microscope slides were found to reduce the fluorescence intensity by about 2 dB compared with the borosilicate slide. The third issue of photobleaching in the fluorescence of the Porphyromonas gingivalis was studied. This study proposes a method of classifying three bacteria based on the spectral intensity ratios (510/635 and 500/635 nm) under the 405 nm excitation light was proposed in this study. The sensitivity and specificity of the classification were approximately 99% and 99%, respectively.
The magnetostriction and dynamic characteristics of Tb0.27Dy0.73Fe2 polycrystals with <110> axial alignment were investigated by standard strain gauge, two coil induction and lock-in amplifier techniques. It is found that the magnetostriction of the sample quickly increases with increasing magnetic fields when H≤80 kA/m under a pressure of 5 or 10 MPa and a “jump” effect occurs during the magnetization process. The dynamic strain coefficient, d33, dynamic incremental permeability,μ33, and magneto-mechanical coupling coefficient, k33, for the Tb0.3Dy0.7Fe2 rod polycrystal sample with <110> axial alignment were measured and discussed. The Tb0.27Dy0.73Fe2 polycrystals with <110> axial alignment possesses excellent magnetostrictive properties along the <110> rod direction in low magnetic fields and it is very useful in application of industry.
The Tb0.3Dy0.7Fe2 <110> oriented alloy was grown by zone melting directional solidification technique. The strain-stress loops of the alloy in different magnetic fields have been measured, and the effect of stress and magnetic field on strain difference Dε has been confirmed. It is found that the strain difference Dε quickly increases with increasing the stress when the stress is less than 10 MPa and decreases in the range of 10-40 MPa when the magnetic field is in the range of 30-40 kA/m. The result indicates that the magnetic field and stress have a marked effect on the strain hysteresis of the Tb0.3Dy0.7Fe2 <110> oriented alloy and the hysteresis property of stress-strain relation should be considered during the design of magnetostrictive sensors.
The structure, magnetization and magnetostriction of Sm(Zn1-xTx) (T=Fe, Co)
polycrystalline alloys were investigated by X-ray diffraction, vibrating sample magnetometer and
standard strain gauge techniques. It is found that annealed SmZn1-xFex alloys show a single
Sm(Zn,Fe) phase with the CsCl-type cubic structure when x≤0.2. SmZn1-xCox alloys are a single
Sm(Zn,Co) phase when x≤0.15 and the Sm-rich phase appears when x>0.15. The Curie temperature
for SmZn1-xFex alloys increases with increasing Fe content in the range of 0≤x≤0.2 and that of
SmZn1-xCox alloys slowly does in the same composition range. When Fe is substituted for Zn in
SmZn compound, the magnetization and magnetostriction increase with increasing the Fe content
when x≤0.2 and when x≤0.1, respectively. The magnetostriction of Sm(Zn1-xCox) alloys increases
with increasing the Co content under the magnetic field of 320 kA/m in the range of 0< x≤0.1.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.