Search

With the rapid improvement of equipment integration technology, multi-spectrum detectors are integrated into compact volumes and widely used for object detection. Confront with this challenge, it is essential to propose a strategy to design a single-layer metasurface with multi-spectrum responses in microwave and infrared ranges. In this work, we proposed a method of designing meta-atoms, which is capable of achieving functional electromagnetic response at microwave and infrared individually. As a demonstration, a metasurface with four different occupation ratios and coding permutation features is designed, fabricated, and tested. In the microwave band, the pixel meta-atom is designed to realize highly efficient cross-polarization conversion between 5.0 and 10.0 GHz, which shows the metasurface can behave as ultra-low Radar Cross Section (RCS) reflectors in the working band; In the infrared band, different occupation ratio of meta-atoms are designed to realize the infrared emissivity from 0.60 to 0.80 in 3–14 μm, which can be used to exhibit digital infrared camouflage pattern. This work promotes the ability to use single-layer design to achieve digital infrared camouflage and microwave RCS reduction simultaneously. The one-layer design is simple in geometry, simplified in process, low cost in economy, and large scale in fabrication, which can promote practical use in compatible microwave stealth and infrared camouflage.

ObjectiveTo Investigate the cause of a food poisoning incident in a city in Dehong Prefecture， determine the scope of the incident， and to formulate effective prevention and control measures.MethodsField epidemiology and case-control study methods were used to formulate case definition； carry out case search； find suspicious food combined with clinical manifestations， dining history and other information； and collect samples from the suspicious food， cases and environment for laboratory testing.ResultsA total of 160 cases were found and the incidence rate was 26.02% （160/615）. The main clinical manifestations were diarrhea， leukocytosis， vomiting， nausea and abdominal pain. The average incubation period was 10.89±5.09 h， with 2 h as the shortest and 28 h as the longest. The epidemiological curve suggested the point source exposure mode. The results of case-control study showed that eating roast pork with green shoots was an independent risk factor （OR=13.09， 95%CI： 3.26‒52.54）.16 samples were tested by the local CDC laboratory. Proteus mirabilis was detected in two the anal swabs of two patients He and Chen. Both proteus pani and proteus mirabilis were detected in anal swab of patient Zhou and Proteus pani was detected in roast meat. There was no detection of pathogenic bacteria in other samples.ConclusionBased on the field epidemiological investigation and laboratory test results， we conclude that the food poisoning incident is caused by suspected proteus bacteria. We suggest that the market supervision department should strengthen the supervision of local food hygiene； clarify the sampling rights， responsibilities and technical procedures when medical institutions treat patients with foodborne diseases； ensure finding the causes in time； and take effective prevention and control measures to avoid similar food poisoning events.

V79 cells were exposed to whole cigarette smoke for 1 hour with 4 cigarettes per hour, 6 cigarettes per hour and 8 cigarettes per hour respectively. ROS, SOD, GSH-Px, CAT and T-AOC were taken as index,and the effects of cigarette smoke on the antioxidant capacity of V79 cells were studied. The results showed that the whole smoke environment will consume and inhibit the antioxidant substance in the cell, which leads to the increase of the content of active oxygen free radical in cells.

As two groups of bases in fibers, cylindrical vector (CV) modes and the orbital angular momentum (OAM) modes can be transformed into each other. Several transformation relations have been studied in previous works, such as σ^+OAM+l=HEl+1,meven+iHEl+1,modd.${\hat \sigma ^ + }OA{M_{ + l}} = HE_{l + 1,m}^{even} + iHE_{l + 1,m}^{odd}.$ However, these relations are discussed in the limitation of equal amplitude, limited phase difference (kπ2, k∈Z)$\left( {{{k\pi } \over 2},{\rm{ }}k \in Z} \right)$ and finite (generally two) mode bases. Complete connection between the CV and OAM modes has not been found. In this paper, a four-dimensional complex space model is constructed to describe arbitrary CV and OAM modes. The reliability of the model is verified by previously reported results and our experiment results. The complete transformation relation between the CV modes and OAM modes is well described in the model. Furthermore, two common kinds of relations have been researched, that is, a single arbitrary polarized OAM mode and two arbitrary orthogonal polarized OAM modes and their corresponding CV modes. These two kinds of states include most of previously reported states, and some new states have not been reported.

Mode-division multiplexing (MDM) is a promising technology for increasing the data-carrying capacity of a single few-mode optical fiber. The flexible mode manipulation would be highly desired in a robust MDM network. Recently, orbital angular momentum (OAM) modes have received wide attention as a new spatial mode basis. In this paper, we firstly proposed a long period fiber grating (LPFG) system to realize mode conversions between the higher order LP core modes in four-mode fiber. Based on the proposed system, we, for the first time, demonstrate the controllable all-fiber generation and conversion of the higher order LP core modes to the first and second order circularly polarized OAM beams with all the combinations of spin and OAM. Therefore, the proposed LPFG system can be potentially used as a controllable higher order OAM beam switch and a physical layer of the translating protocol from the conventional LP modes communication to the OAM modes communication in the future mode carrier telecommunication system and light calculation protocols.

In view of problems of big flux linkage and torque ripple, imprecise low speed control of conventional direct torque control of induction motors, the paper proposed a new direct torque control method based on sliding mode variable structure on basis of establishment of mathematical model of induction motor under α-β coordinate system. The method uses speed sliding mode variable structure controller to replace PI controller of conventional direct torque control, which can effectively reduce flux linkage and torque ripple of conventional direct torque control, enhance stability of the system. The simulation results proved validity of the method.

Abstract Background Atherosclerosis is considered to be a chronic inflammatory disease. Astragali Radix extract (ARE) is one of the major active ingredients extracted from the root of Astragalus membranaceus Bge. Although ARE has an anti-inflammatory function, its anti-atherosclerotic effects and mechanisms have not yet been elucidated. Methods Murine endothelial SVEC4-10 cells were pretreated with different doses of ARE at different times prior to induction with tumor necrosis factor (TNF)-α. Cell adhesion assays were performed using THP-1 cells and assessed by enzyme-linked immunosorbent assay, western blotting and immunofluorescence analyses to detect the expression of vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), phosphorylated inhibitor of κB (p-iκB) and nuclear factor (NF)-κB. We also examined the effect of ARE on atherosclerosis in the aortic endothelium of apolipoprotein E-deficient (apoE−/−) mice. Results TNF-α strongly increased the expression of VCAM-1 and ICAM-1 accompanied by increased expression of p-iκB and NF-κB proteins. However, the expression levels of VCAM-1 and ICAM-1 were reduced by ARE in dose- and time-dependent manners, with the strongest effect at a dose of 120 μg/ml incubated for 4 h. This was accompanied by significantly decreased expression of p-iκB and inhibited activation of NF-κB. Immunofluorescence analysis also revealed that oral administration of ARE resulted in downregulation of adhesion molecules and decreased expression of macrophages in the aortic endothelium of apoE−/− mice. ARE could suppress the inflammatory reaction and inhibit the progression of atherosclerotic lesions in apoE−/− mice. Conclusion This study demonstrated that ARE might be an effective anti-inflammatory agent for the treatment of atherosclerosis, possibly acting via the decreased expression of adhesion molecules.