In robot inertial navigation systems, to deal with the problems of drift and noise in the gyroscope and accelerometer and the high computational cost when using extended Kalman filter (EKF) and particle filter (PF), a complementary filtering algorithm is utilized. By combining the Inertial Measurement Unit (IMU) multi-sensor signals, the attitude data are corrected, and the high-precision attitude angles are obtained. In this paper, the quaternion algorithm is used to describe the attitude motion, and the process of attitude estimation is analyzed in detail. Moreover, the models of the sensor and system are given. Ultimately, the attitude angles are estimated by using the quaternion extended Kalman filter, linear complementary filter, and Mahony complementary filter, respectively. The experimental results show that the Mahony complementary filtering algorithm has less computational cost than the extended Kalman filtering algorithm, while the attitude estimation accuracy of these two algorithms is similar, which reveals that Mahony complementary filtering is more suitable for low-cost embedded systems.
Background: To explore the contribution of type 2 diabetes mellitus (T2DM) to hypothalamic inflammation and depressive disorders in young patients with obesity.Methods: According to the diagnostic criteria for T2DM, all of patients with obesity were divided into the diabetic and the non-diabetic groups. The severity of depressive disorders was assessed by self-rating depression scale (SDS). The signal intensity (SI) ratio of the T2-weighted phase of the superior hypothalamus/ amygdala (H/A) was measured using a quantitative magnetic resonance imaging (MRI) technique to evaluate hypothalamic inflammation. Univariate and multivariate logistic regression analysis was used to find the influencing factors of depressive disorder. The prediction equation's sensitivity and specificity for the depressive disorder were calculated based on the receiver operating characteristic (ROC) curve.
Results:In young patients with obesity and diabetes, the incidence of depression is 79.49%, which was much higher than that in patients without diabetes (P<0.001). The SI of the left H/A in young patients with obesity and diabetes is significantly higher than that in non-diabetic patients (P<0.001). The relative risks of depression are fasting blood glucose (FBG) (
The discovery of
specific matter phases with abnormal physical
properties in low-dimensional systems and/or on particular substrates,
such as the hexagonal phase of ice and two-dimensional (2D) CaCl with
an abnormal valence state, continuously reveals more fundamental mechanisms
of the nature. Alkali halides, represented by NaCl, are one of the
most common compounds and usually thought to be well-understood. In
the past decades, many theoretical studies suggested the existence
of one particular phase, that is, the graphitic-like hexagonal phase
of alkali halides at high pressure or in low-dimension states, with
the expectation of improved properties of this matter phase but lacking
experimental evidence due to severe technical challenges. Here, by
optimized cryo-electron microscopy, we report the direct atomic-resolution
observation and in situ characterization of the prevalent and stable
graphitic-like alkali halide hexagonal phases, which were spontaneously
formed by unsaturated NaCl and LiCl solution, respectively, in the
quasi-2D confined space between reduced graphene oxide layers under
ambient conditions. Combined with a control experiment, density functional
theory calculations, and previous theoretical studies, we believe
that a delicate balance among the cation−π interaction
of the solute and substrate, electrostatic interactions of anions
and cations, solute–solvent interactions, and thermodynamics
under confinement synergistically results in the formation of such
hexagonal crystalline phases. These findings highlight the effects
of the substrate and the confined space on the formation of specific
matter phases and provide a universal scheme for the preparation of
special graphitic-like hexagonal phases of alkali halides.
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