RESUMO
Most of the existing stretchable strain sensors are based on the contact-resistance mechanism, where the stretchability and resistance variation depend on the change of the contact relationship of the conductive microstructures. These sensors usually exhibit large sensing ranges and gauge factors but unsatisfactory repeatability and linearity of the electrical responses because the contact is unstable. Here, we report a completely different design for stretchable strain sensors based on a contact-resistance-free structure, i.e., the off-axis serpentine sandwich structure (OASSS), with the mechanism of the stretch-bending-stretch transformation (SBST). Neither unstable contact resistance nor nonlinear constitutive and geometric behaviors occur for the OASSS while the sensor undergoes a large applied strain (50%), which guarantees high repeatability (repeatability error = 1.58%) and linearity (goodness-of-fit >0.999). Owing to such performances, the present sensors are not only applied to monitoring human activities and medical surgery but also to the ground tests of Tianwen-1, China's first Mars exploration mission.
Assuntos
Dispositivos Eletrônicos Vestíveis , Humanos , Condutividade ElétricaRESUMO
Foldable and deployable flexible composite thin-walled structures have the characteristics of light weight, excellent mechanical properties and large deformation ability, which means they have good application prospects in the aerospace field. In this paper, a simplified theoretical model for predicting the position of the neutral section of a lenticular deployable composite boom (DCB) in tensile deformation is proposed. The three-dimensional lenticular DCB is simplified as a two-dimensional spring system and a rigid rod, distributed in parallel along the length direction. The position of the neutral cross-section can be determined by solving the balance equations and geometric relations. In order to verify the validity of the theoretical model, a finite element model of the tensile deformation of a lenticular DCB was established. The theoretical prediction results were compared with the finite element calculation results, and the two results were in good agreement.
RESUMO
Objective: This study aimed to identify the clinical features of Kawasaki disease shock syndrome (KDSS) in children. Methods: The case-control studies of KDSS and KD children up until April 30, 2021 were searched in multiple databases. The qualified research were retrieved by manually reviewing the references. Review Manager 5.3 software was used for statistical analysis. Results: The results showed that there was no significant difference in the incidence of male and female in children with KDSS. Children with KDSS compared with non-shocked KD, there were significant difference in age, duration of fever, white blood cell (WBC) count, percentage of neutrophils (NEUT%), platelet count (PLT), c-reactive protein level (CRP), alanine transaminase concentration (ALT), aspartate transaminase concentration (AST), albumin concentration (ALB), sodium concentration (Na), ejection fraction, and length of hospitalization as well as the incidence of coronary artery dilation, coronary artery aneurysm, left ventricular dysfunction, mitral regurgitation, pericardial effusion, initial diagnosis of KD, intravenous immunoglobulin (IVIG) resistance and receiving second dose of IVIG, vasoactive drugs, hormones, and albumin. In contrast, there was no difference in the hemoglobin concentration, erythrocyte sedimentation rate, and the incidence of conjunctival injection, oropharyngeal change, polymorphous rash, extremity change, and incomplete KD. Conclusion: Current evidence suggested that the children with KDSS had more severe indicators of inflammation and more cardiac abnormalities. These patients were resistant to immunoglobulin treatment and required extra anti-inflammatory treatment. Systematic Review Registration: PROSPERO registration number CRD42021241207.
RESUMO
The purpose of this study was to investigate the status of organochlorine pesticide residues in 186 ginseng samples collected in Jilin, People's Republic of China. Based on the Chinese Pharmacopoeia 2015 method for detection of organochlorine pesticide residues in ginseng, 22 organochlorine pesticide residues were identified. Chlordane, aldrin, epichlorohydrin, and dieldrin and their isomers were not detected in ginseng from this region. Heptachlor was detected in only one ginseng sample, and the concentration did not exceed the maximum residual limit (MRL) prescribed in the Pharmacopoeia (0.05 mg/kg). Benzene hexachloride was detected in two samples, one of which was above the MRL. Hexachlorobenzene and pentachloronitrobenzene (quintozene) were found in 11.8 and 52.1% of the samples, respectively, and the residues in these samples exceeded the MRL by 4.3 and 8.6%, respectively.
