Leaky Cable Fixture Detection in Railway Tunnel Based on RW DCGAN and Compressed GS-YOLOv5

The communication system of high-speed trains in railway tunnels needs to be built with leaky cables fixed on the tunnel wall with special fixtures.To ensure safety,checking the regular leaky cable fixture is necessary to elimi-nate the potential danger.At present,the existing fixture detection algorithms are difficult to take into account detection accuracy and speed at the same time.The faulty fixture is also insufficient and difficult to obtain,seriously affecting the model detection effect.To solve these problems,an innovative detection method is proposed in this paper.Firstly,we presented the Res-Net and Wasserstein-Deep Convolution GAN(RW-DCGAN)to implement data augmentation,which can enable the faulty fixture to export more high-quality and irregular images.Secondly,we proposed the Ghost SENet-YOLOv5(GS-YOLOv5)to enhance the expression of fixture feature,and further improve the detection accuracy and speed.Finally,we adopted the model compression strategy to prune redundant channels,and visualized training details with Grad-CAM to verify the reliability of our model.Experimental results show that the algorithm model is 69.06%smaller than the original YOLOv5 model,with 70.07%fewer parameters,2.1%higher accuracy and 14.82 fps faster speed,meeting the needs of tunnel fixture detection.

高拉伸自黏附导电P(AAS-VPA)/P(EA-MAA)复合水凝胶的传感应用

以丙烯酸钠(AAS)、丙烯酸乙酯-甲基丙烯酸共聚物P(EA-MAA)和乙烯磷酸(VPA)为原料,制备了具有高拉伸性(>2000%的断裂伸长率)、良好的电导率(~0.0343 S/cm)及优异的表面自适应性黏附力(黏附金属、玻璃、木材、橡胶等多种基材,其中对橡胶的黏附强度高达250 N/m)的复合水凝胶P(AAS-VPA)/P(EA-MAA)。该水凝胶不仅能够随皮肤适时变形,而且具有高的灵敏度(GF=4.40)、宽的应变范围(0%~200%)及良好的稳定性,能够动态监测身体的各类运动(诸如手指弯曲、胳膊弯曲等)。这种集高拉伸性、导电性及自黏性于一体的多功能水凝胶能够适应多种应用场景,为水凝胶在柔性电子领域的应用提供了材料范例。

A Fault Current Limiting Hybrid DC Circuit Breaker

Due to the low impedance characteristic of the high voltage direct current(HVDC)grid,the fault current rises extremely fast after a DC-side fault occurs,and this phenomenon seriously endangers the safety of the HVDC grid.In order to suppress the rising speed of the fault current and reduce the current interruption requirements of the main breaker(MB),a fault current limiting hybrid DC circuit breaker(FCL-HCB)has been proposed in this paper,and it has the capability of bidirectional fault current limiting and fault current interruption.After the occurrence of the overcurrent in the HVDC grid,the current limiting circuit(CLC)of FCL-HCB is put into operation immediately,and whether the protected line is cut off or resumed to normal operation is decided according to the fault detection result.Compared with the traditional hybrid DC circuit breaker(HCB),the required number of semiconductor switches and the peak value of fault current after fault occurs are greatly reduced by adopting the proposed device.Extensive simulations also verify the effectiveness of the proposed FCL-HCB.

Lgr5^+ intestinal stem cell sorting and organoid culture

Intestinal epithelial stem cells (IESCs) are one of the most rapidly self‐renewing and proliferating adult stem cells. The IESCs reside at the bottom of intestinal and colonic crypts, giving rise to all intestinal epithelial lineages and maintaining intestinal epithelial replenishment. The technique of three‐dimensional culture based upon intestinal stem cell biology has been recently developed to study gastrointestinal development and disease pathogenesis. Here, we summarize the techniques used to isolate Lgr5‐ positive IESCs to form the enteroids from intestine or colonoids from colon, and present the means to examine these organoid functions. This study will provide a simple and practical way for producing intestinal tissues in the laboratory.

Hydroxyl radical production by abiotic oxidation of pyrite under estuarine conditions:The effects of aging,seawater anions and illumination

Pyrite is widely distributed in estuarine sediments as an inexpensive natural Fenton-like reagent,however,the mechanism on the hydroxyl radical(HO^(·))production by pyrite under estuarine environmental conditions is still poorly understood.The batch experiments were performed to investigate the effects of estuarine conditions including aging(in air,in water),seawater anions(Cl^(-),Br^(-)and HCO_(3)^(-))and light on the HO^(·)production by pyrite oxidation.The one-electron transfer dominated the process from O_(2) to HO^(·)induced by oxidation of pyrite.The Fe(oxyhydr)oxide coatings on the surface of pyrite aged in air and water consumed hydrogen peroxide while mediating the electron transfer,and the combined effect of the two resulted in a suppression of HO^(·)production in the early stage of aging and a promotion of HO^(·)production in the later stage of aging.Corrosion of the surface oxide layers by aggressive anions was the main reason for the inhibition of HO^(·)production by Cl^(-)and Br^(-),and the generation of Cl^(·)and Br^(·)may also play a role in the scavenging of HO^(·).HCO_(3)^(-)increased the average rate of HO^(·)production through surface-CO_(2) complexes formed by adsorption on the surface of pyrite.The significant enhancement of HO^(·)production under light was attributed to the formation of photoelectrons induced by photochemical reactions on pyrite and its surface oxide layers.These findings provide new insights into the environmental chemical behavior of pyrite in the estuary and enrich the understanding of natural remediation of estuarine environments.

SARS-CoV-2 crosses the blood-brain barrier accompanied with basement membrane disruption without tight junctions alteration

SARS-CoV-2 has been reported to show a capacity for invading the brains of humans and model animals.However,it remains undear whether and how SARS-CoV-2 crosses the blood-brain barrier(BBB).Herein,SARS-CoV-2 RNA was occasionally detected in the vascular wall and perivascular space,as well as in brain microvascular endothelial cells(BMECs)in the infected K18-hACE2 transgenic mice.Moreover,the permeability of the infected vessel was in creased.Furthermore,disin tegrity of BBB was discovered in the infected hamsters by administration of Evans blue.Interestingly,the expression of claudin5,ZO-1,occludin and the ultrastructure of tight junctions(TJs)showed unchanged,whereas,the basement membrane was disrupted in the infected animals.Using an in vitro BBB model that comprises primary BMECs with astrocytes,SARS-CoV-2 was found to infect and cross through the BMECs.Consistent with in vivo experiments,the expression of MMP9 was increased and collagen IV was decreased while the markers for TJs were not altered in the SARS-CoV-2-infected BMECs.Besides,inflammatory responses including vasculitis,glial activation,and upregulated inflammatory factors occurred after SARS-CoV-2 infection.Overall,our results provide evidence supporting that SARS-CoV-2 can cross the BBB in a transcellular pathway accompanied with basement membrane disrupted without obvious alteration of TJs.

Flood-illuminated adaptive optics ophthalmoscope with a single curved relay mirror

For decreasing light loss and diminishing the aberrations of the optical system,an open-loop adaptive optics(AO)system for retinal imaging in vivo is introduced.Taking advantage of the ability of young human eyes to accommodate,there was only one single curved mirror to make the pupil of the eye conjugate with the wavefront corrector and the wavefront sensor.A liquid crystal spatial light modulator(LC-SLM)was adopted as the wavefront corrector because the LC-SLM can be made in a small size to match the sensor.To reduce a pair of lenses or focusing mirrors,the wavefront corrector and sensor are positioned in the noncommon path.The system adopts open-loop control and the high-precision LC-SLM guarantees the effectiveness of the AO system.The designed field of view is 1°on the retina(about 300μm).The image quality was simulated with different mirror surface types,including circular,parabolic,and hyperbolic.A hyperbolic mirror with conic constant−1.07,which is close to−1,could best eliminate the aberrations.Theoretical analysis showed that the optical throughput of this system was at least 22.4%higher than that of a standard transmission AO system.In a practical experiment,a parabolic mirror was positioned in the optical path.Images of the cone photoreceptors and the capillary vessels were obtained successfully.This system simplifies the optical setup in comparison to the commonly used 4F systems while still guaranteeing the effectiveness of AO to correct the ocular aberrations.