1,011 research outputs found
Model of a microtoroidal magnetometer
We present a model of a cavity optomechanical magnetic field sensor based on a microtoroidal resonator. The magnetic field induced expansion of a magnetostrictive material is transduced onto the physical structure of a highly compliant optical microresonator. The resulting motion is read out optically with ultra-high sensitivity. According to our theoretical model sensitivities of up to 750 fT/√ Hz may be possible. The simultaneous presence of high-quality mechanical and optical resonances in microtoroids greatly enhances both the response to the magnetic field and the measurement sensitivity
Cavity Optomechanical Magnetometer
A cavity optomechanical magnetometer is demonstrated where the magnetic field
induced expansion of a magnetostrictive material is transduced onto the
physical structure of a highly compliant optical microresonator. The resulting
motion is read out optically with ultra-high sensitivity. Detecting the
magnetostrictive deformation of Terfenol-D with a toroidal whispering gallery
mode (TWGM) resonator a peak sensitivity of 400 nT/Hz^.5 was achieved with
theoretical modelling predicting that sensitivities of up to 500 fT/Hz^.5 may
be possible. This chip-based magnetometer combines high-sensitivity and large
dynamic range with small size and room temperature operation
Sensitivity of cavity optomechanical field sensors
This article presents a technique for modeling cavity optomechanical field sensors. A magnetic or electric field induces a spatially varying strain across the sensor. The effect of this strain is accounted for by separating the mechanical motion of the sensor into eigenmodes, each modeled by a simple harmonic oscillator. The force induced on each oscillator can then be determined from an overlap integral between strain and the corresponding eigenmode, with the optomechanical coupling strength determining the ultimate resolution with which this force can be detected
Fracture properties of CrN hard coatings: Influence of the microstructure, alloying elements, and coating architecture
Transition metal nitrides are well known and applied as protective coating materials based on their unique refractory characteristics, such as high hardness or Young’s modulus. However, for long-term applications, the fracture toughness KIC is an essential factor as the integrity of the coating-substrate interface is impaired by cracking and subsequent environmental attacks.
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Genome-wide association study of borderline personality disorder reveals genetic overlap with bipolar disorder, major depression and schizophrenia
Borderline personality disorder (BOR) is determined by environmental and
genetic factors, and characterized by affective instability and impulsivity,
diagnostic symptoms also observed in manic phases of bipolar disorder (BIP).
Up to 20% of BIP patients show comorbidity with BOR. This report describes the
first case–control genome-wide association study (GWAS) of BOR, performed in
one of the largest BOR patient samples worldwide. The focus of our analysis
was (i) to detect genes and gene sets involved in BOR and (ii) to investigate
the genetic overlap with BIP. As there is considerable genetic overlap between
BIP, major depression (MDD) and schizophrenia (SCZ) and a high comorbidity of
BOR and MDD, we also analyzed the genetic overlap of BOR with SCZ and MDD.
GWAS, gene-based tests and gene-set analyses were performed in 998 BOR
patients and 1545 controls. Linkage disequilibrium score regression was used
to detect the genetic overlap between BOR and these disorders. Single marker
analysis revealed no significant association after correction for multiple
testing. Gene-based analysis yielded two significant genes: DPYD (P=4.42 ×
10−7) and PKP4 (P=8.67 × 10−7); and gene-set analysis yielded a significant
finding for exocytosis (GO:0006887, PFDR=0.019; FDR, false discovery rate).
Prior studies have implicated DPYD, PKP4 and exocytosis in BIP and SCZ. The
most notable finding of the present study was the genetic overlap of BOR with
BIP (rg=0.28 [P=2.99 × 10−3]), SCZ (rg=0.34 [P=4.37 × 10−5]) and MDD (rg=0.57
[P=1.04 × 10−3]). We believe our study is the first to demonstrate that BOR
overlaps with BIP, MDD and SCZ on the genetic level. Whether this is confined
to transdiagnostic clinical symptoms should be examined in future studies
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