166 research outputs found

    An equivalent-effect phenomenon in eddy current non-destructive testing of thin structures

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    The inductance/impedance due to thin metallic structures in non-destructive testing (NDT) is difficult to evaluate. In particular, in Finite Element Method (FEM) eddy current simulation, an extremely fine mesh is required to accurately simulate skin effects especially at high frequencies, and this could cause an extremely large total mesh for the whole problem, i.e. including, for example, other surrounding structures and excitation sources like coils. Consequently, intensive computation requirements are needed. In this paper, an equivalent-effect phenomenon is found, which has revealed that alternative structures can produce the same effect on the sensor response, i.e. mutual impedance/inductance of coupled coils if a relationship (reciprocal relationship) between the electrical conductivity and the thickness of the structure is observed. By using this relationship, the mutual inductance/impedance can be calculated from the equivalent structures with much fewer mesh elements, which can significantly save the computation time. In eddy current NDT, coils inductance/impedance is normally used as a critical parameter for various industrial applications, such as flaw detection, coating and microstructure sensing. Theoretical derivation, measurements and simulations have been presented to verify the feasibility of the proposed phenomenon

    β-Adrenergic system, a backstage manipulator regulating tumour progression and drug target in cancer therapy

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    Abstractβ-Adrenoceptors are broadly distributed in various tissues of the body. Stress hormones regulate a panel of important physiological functions and disease states including cancer. Nicotine and its derivatives could stimulate the release of stress hormones from cancer cells, leading to the promotion of cancer development. β-Blockers have been widely used to control hypertension for decades. Recently, these agents could have significant implications in cancer therapy through blockade of adrenoceptors in tumour tissues. In this review, we summarize recent advancements about the influence of stress hormones, nicotine and β-adrenoceptors on cancer cell proliferation, apoptosis, invasion and metastasis, and also tumour vasculature normalization. Relevant signal pathways and potential value of β-blockers in the treatment of cancer are also discussed in this review

    SRCD: Semantic Reasoning with Compound Domains for Single-Domain Generalized Object Detection

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    This paper provides a novel framework for single-domain generalized object detection (i.e., Single-DGOD), where we are interested in learning and maintaining the semantic structures of self-augmented compound cross-domain samples to enhance the model's generalization ability. Different from DGOD trained on multiple source domains, Single-DGOD is far more challenging to generalize well to multiple target domains with only one single source domain. Existing methods mostly adopt a similar treatment from DGOD to learn domain-invariant features by decoupling or compressing the semantic space. However, there may have two potential limitations: 1) pseudo attribute-label correlation, due to extremely scarce single-domain data; and 2) the semantic structural information is usually ignored, i.e., we found the affinities of instance-level semantic relations in samples are crucial to model generalization. In this paper, we introduce Semantic Reasoning with Compound Domains (SRCD) for Single-DGOD. Specifically, our SRCD contains two main components, namely, the texture-based self-augmentation (TBSA) module, and the local-global semantic reasoning (LGSR) module. TBSA aims to eliminate the effects of irrelevant attributes associated with labels, such as light, shadow, color, etc., at the image level by a light-yet-efficient self-augmentation. Moreover, LGSR is used to further model the semantic relationships on instance features to uncover and maintain the intrinsic semantic structures. Extensive experiments on multiple benchmarks demonstrate the effectiveness of the proposed SRCD.Comment: 10 pages, 5 figure

    On-line detection of spherical sensor for inrush current detection

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    With the exploration and demand for the field of marine, underwater vehicles are used in deep water widely, however, there is a lack of research about underwater vehicles which are applied in shallow wary water. When underwater vehicles working in shallow wary water, they will be affected by the inrush current effect of shallow waters, so the research of underwater vehicles about anti current control becomes a meaningful item. But due to the high cost of underwater work, simulation and analysis to the inrush current online detection mechanism first, to determine the effects of surge phenomenon of underwater vehicles. Electromotor drives propeller to generate the flow, the detection mechanism is subjected to the impact of all directions. For some mechanical analysis of the inrush current online detection mechanism and analyzing the influence on the water inrush current when it moved in this paper, so we can reduce the effects of water inrush current on underwater vehicles in the subsequent experiments

    Research on energy dissipation characteristics and coal burst tendency of fissured coal mass

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    Coal burst tendency is the natural property of whether coal rock mass can have coal burst, and the distribution of fissures has an important influence on it. In order to study the influence mechanism of the original coal fissures on the energy dissipation characteristics and coal burst tendency, the PFC2D numerical simulation method was used to conduct uniaxial compression tests on coal specimens with different fracture types. The results show that: ①With the increase of the inclination angle of the fissure, the compressive strength and elastic modulus of the macroscopic mechanical parameters show a trend of decreasing first and then increasing; when the inclination angle of the fissure is 30, both of them reach the minimum value. The relationship between the macro-mechanical parameters of different fracture types is: non-coplanar parallel double-fissure specimen < single-fissure specimen < co-planar discontinuous double-fissure specimen.②The variation law of elastic strain energy and total strain energy is similar to that of macroscopic mechanical parameters. The parallel and non-coplanar fracture specimens form an energy dissipation structure between the fissures, and the coplanar discontinuous double-fissure specimen forms an energy concentration area between the fissures, revealing the intrinsic reason for the relationship between the elastic energy of different fracture types. ③The coal burst tendency is analyzed from the two perspectives of the ability of coal and rock to store elastic energy and the ability to release elastic energy after failure, and two coal burst tendency indicators, elastic energy storage rate and elastic energy release rate, are proposed. ④With the increase of the fissure inclination angle, both the elastic energy storage rate and the elastic energy release rate showed a trend of first decreasing and then increasing; when the fissure inclination angle was 30, the two coal burst propensity indexes both achieved the minimum value. The relationship between the coal burst tendency of different fracture types is: non-coplanar parallel double-fissure specimen < single-fissure specimen < co-planar discontinuous double-fissure specimen. The distribution of fissures has a significant coal burst on the coal burst tendency of coal mass, and the factor of fissures should be considered in the evaluation of the coal burst tendency of coal and rock mass and the prevention and control of rock burst

    PARK16 rs708730 Polymorphism Decreases Parkinson’s Disease Risk in European Ancestry Population: A Meta-analysis

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    Parkinson’s disease (PD) is a complex fatal chronic neurodegenerative disease most common in elderly people. The early genome-wide association studies (GWAS) found that the minor allele variant of PARK16 rs708730 polymorphism is a significant protective factor for PD in Caucasian populations. However, these results cannot be repeated by the following studies in Caucasian populations and other populations. We considered that the inconsistency of the findings may be caused by the small-scale samples or the heterogeneity among different populations. Therefore, in this study, we synthesized the previous related GWAS studies through three authoritative sources, and used the large-scale samples (10,645 PD cases and 30,499 controls) to reevaluate the association between rs708730 polymorphism and PD. The results showed that there is no association between them in Asian ancestry population. While, in European ancestry population, we found that the minor allele variant (G) of rs708730 polymorphism is significantly associated with a decreased risk of PD. Collectively, our findings further verified the association of rs708730 with PD and show its genetic heterogeneity among different populations, which can help to develop a better understanding of the PD’s pathogenesis
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