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Ferritin heavy chain (FerHCH) is a major component of ferritin and plays an important role in maintaining iron homeostasis and redox equilibrium. Our previous studies have demonstrated that the Bombyx mori ferritin heavy chain homolog (BmFerHCH) could respond to B. mori nucleopolyhedrovirus (BmNPV) infection. However, the mechanism by which BmNPV regulates the expression of BmFerHCH remains unclear. In this study, BmFerHCH increased after BmNPV infection and BmNPV infection enhanced nuclear factor kappa B (NF-κB) activity in BmN cells. An NF-κB inhibitor (PDTC) reduced the expression of the virus-induced BmFerHCH in BmN cells, and overexpression of BmRelish (NF-κB) increased the expression of virus-induced BmFerHCH in BmN cells. Furthermore, BmNPV infection enhanced BmFerHCH promoter activity. The potential NF-κB cis-regulatory elements (CREs) in the BmFerHCH promoter were screened by using the JASPAR CORE database, and two effective NF-κB CREs were identified using a dual luciferase reporting system and electrophoretic mobility shift assay (EMSA). BmRelish (NF-κB) bound to NF-κB CREs and promoted the transcription of BmFerHCH. Taken together, BmNPV promotes activation of BmRelish (NF-κB), and activated BmRelish (NF-κB) binds to NF-κB CREs of BmFerHCH promoter to enhance BmFerHCH expression. Our study provides a foundation for future research on the function of BmFerHCH in BmNPV infection.

795 nm vertical-cavity surface-emitting lasers (VCSELs) with in-phase surface gratings are fabricated and investigated theoretically and experimentally. The polarization characteristics of 795 nm VCSELs with various grating periods and depths are analyzed using the rigorous coupled-wave analysis (RCWA) method; the dependence of polarization stability on the profile of gratings demonstrates that the trapezoid grating ridge slightly enhances the orthogonal polarization suppression ratio (OPSR), but increases the threshold current. The fabricated VCSELs with a sub-wavelength in-phase surface grating of a duty cycle of 0.5 show stabilized output polarization at the cost of increasing the threshold current which is in agreement with the calculations. The grating VCSELs with a period of 200 nm and an oxide aperture of3.43µm×4.39µmproduce a single-mode output with an OPSR of 16.6 dB and a slope efficiency of 0.42 W/A at 85°C.

Currently, most explanations of nanotube growth are limited to chemical or field-assisted dissolution, in the belief that an increase in water content will increase the corrosive effect of the electrolyte and accelerate the rate of growth of the nanotubes. Here, titanium foils were anodized at a constant voltage (50 V) in 0.5 wt% NH4F ethylene glycol electrolyte containing 2 wt% H2O or 10 wt% H2O. It was found that the growth rate of nanotubes in electrolyte with 2 wt% H2O was significantly faster than that in electrolyte with 10 wt% H2O, contradicting the traditional dissolution theory. A detailed explanation is given using electronic current theory and the oxygen bubble model. We believe that electronic currents, rather than chemical dissolution, play the key role in nanotube growth. This conclusion was validated by the matched lengths of an interesting two-layer nanotube array obtained by a novel two-step anodization process.

Fourier transform near-infrared spectroscopy (FT-NIRS), coupled with chemometrics techniques, was performed as a fast analysis technique to assess the quality of various components in black tea. Four PLS models, namely partial least square (PLS), synergy interval PLS (Si-PLS), genetic algorithm PLS (GA-PLS) and backward interval PLS (Bi-PLS), were established as calibration models for the quantitative prediction of amino acids, caffeine, theaflavins and water extract. The results are reported based on the lower root mean square error of cross prediction (RMSEP) and the root mean square error of cross-validation (RMSECV) as well as their correlation coefficient (R2) in the prediction set (RP) and the calibration set (RC). In addition, on the basis of fewer frequency variables, GA-PLS was found to be the best technique for the quantification of amino acids and water extract and Bi-PLS was found to be the best technique for the quantitative analysis of caffeine and theaflavins in this study. It was observed that NIR spectroscopy can be successfully combined with various chemometric techniques for the rapid identification of the chemical composition of black tea. This study demonstrates that FT-NIR spectroscopy, combined with chemometrics (GA-PLS and Bi-PLS), has the best stability and generalization performance for black tea analysis.

At present, the use of DC convergence and DC transmission (abbreviated as all DC) is recognized as the most effective technical solution and inevitable trend to solve the flexible access of large-scale new energy generation. However, the high-voltage and large-capacity DC-DC converters used in the DC convergence of the full DC system are still in the preliminary research stage. This paper presents a high voltage and large capacity isolated DC-DC converter topology, which is composed of three-stage boost circuit. The simulation results show that the topology can increase the output voltage of wind turbine from 1kV to 320kV, effectively improve the boost ratio of converter, and provide a theoretical basis for the realization of full DC offshore wind power system.

We report a new strategy for the facile synthesis of TiO2 nanopetal-like film on a titanium substrate, which includes anodization of titanium and subsequent H3PO4 immersion treatment. The formation mechanism of TiO2 nanopetals originated from anodic TiO2 nanotube arrays was suggested. The present technique is not only low-energy, well-controlled and cost-effective, but also obtains P-doped TiO2.

Malathion is an organophosphorus pesticide which could remain in agricultural products and exert irreversible harmful effects on human health. Hence, strict monitoring of malathion contents is very significant. Here, a highly sensitive fluorescent aptasensor was developed for the determination of malathion, the system was based on a cationic polymer-mediated fluorescence ‘turn-off’. In this system, malathion-specific aptamers were bound to cationic polymer through electrostatic interactions. To produce fluorescence resonance energy transfer (FRET), negatively charged upconversion fluorescent nanoparticles (UCNPs) and cationic-polymer encapsulated gold nanoparticles (GNPs) were combined. This combination resulted in fluorescence quenching, and the degree of quenching was correlated with the concentration of malathion. Under optimum conditions, the fluorescence intensities were observed to decrease linearly with the rising concentration of the malathion from 0.01 to 1 μM with a detection limit of 1.42 nM. Furthermore, the developed sensor possessed good selective recognition ability for malathion and was successfully used to detect malathion in adulterated tap water and matcha samples with high accuracy.

In this study, we have design a new biosensor for E. coli, based on the fluorescence resonance energy transfer (FRET) between aptamer modified upconversion nanoparticles (UCNPs) as donors and layered tungsten disulfide (WS2) nanosheets as the effective acceptor. The aptamer modified-UCNPs can be fetched nearest to the WS2 surface, because of the potent van der Waals force between the nucleobases of aptamer and the basal plane of WS2. The spectral overlap between UCNPs fluorescence emission and WS2 absorption permits the occurrence of FRET, resulted in quenching of upconversion fluorescence. In the presence of E. coli, the specific aptamer preferentially bind to E. coli, causing changes in the conformation of aptamer, a phenomenon directs the dissociation of mixing probe away from the surface of WS2 nanosheets and therefore parts of the quenched fluorescence of UCNPs was retrieved. The fluorescence intensity increased with the raised concentration of E. coli. The aptasensor exhibited limitary over the concentration range 85 to 85 × 107 cfu mL−1 for E. coli and the detection limit (LOD) was 17 cfu mL−1. In addition, the proposed biosensing method comprehended huge advantages including the facile operation procedure, high sensitivity and selectivity, which confer a great potential for the quantification of E. coli in medical diagnostics, food and environmental analysis.

In the traditional public area pedestrian flow monitoring, a lot of manpower and material resources are needed. Only relying on people’s eyes to identify and count the number of people in the video under monitoring is not only inefficient, but also has errors in accuracy and wastes a certain amount of energy and financial resources. In the rapid development trend of artificial intelligence, this system starts from the perspective of real-time monitoring, with the maturity and development of machine vision technology, and creates a cloud monitoring platform based on JavaWeb technology. The pedestrian detection technology is applied to the pedestrian flow monitoring, which provides a feasible scheme for accurate and fast pedestrian flow monitoring and warning, and develops a system to help public area managers and government departments to deal with the crowd gathering situation, analyze and monitor the crowd density, and give a quick warning to the crowd outbreak and gathering place.

This paper demonstrates the application of surface-enhanced Raman scattering (SERS) using positive charged gold nanorods (Au NRs) as an enhancement substrate to classify Pseudomonas spp. coupled with multivariate methods. Four species of Pseudomonas as dominant spoilage bacteria of food were isolated from rotten chicken, namely, Pseudomonas gessardii (P9), Pseudomonas psychrophila (P8), Pseudomonas psychrophila (S2) and Pseudomonas fluorescens (T3). Au NRs were synthesized with positive charge by seed-mediated growth method which can be adsorbed onto the surface of the bacteria by electrostatic adsorption. SERS spectra were collected individually for four types of Pseudomonas and pretreated by mean centering (MC), then principal component analysis (PCA) and hierarchical clustering analysis (LDA) were used to achieve data dimensionality reduction and visualize the result of differentiation for the species of Pseudomonas. Particularly, the classification accuracy of LDA was reached to 100%. Following we applied hierarchical clustering analysis (HCA) to cluster each species of Pseudomonas and the results of HCA consistent with the results of 16S rRNA. This study has shown that SERS combined with LDA and HCA can be used as a reliable method to classify Pseudomonas.

When using photogrammetric method to measure axial forgings, it is impossible to measure the points' coordinates of the same section or spiral line, so the conventional method to evaluate the cylindricity error can't be used. In this paper, a cylindricity error evaluation algorithm based on mechanical thinking is proposed. The measurement points which are near the same shaft parts are divided into a group and projected onto the fitting surface of the bottom of shaft parts. Each group of projected points can do ellipse fitting to obtained the center coordinates. The initial axis equation is obtained through two sets of point coordinates which are the mean value of the coordinates obtained on the bottom surface. Different from grid method and genetic algorithm, the optimal axis equation is obtained by adjusting the axis equation in the corresponding direction based on the mechanical thought and the operation speed is accelerated by changing step length. Experimental results show that this method is equivalent to the traditional measurement method, besides it's simple and efficient without tedious process on measuring the points.

The method of visual positioning can be mainly divided into fixed camera system and mobile camera system. In this paper, we propose a dynamic target positioning method based on ROI (regions of interest), which utilizes the deep learning method to detect targets and employs the fixed camera system to locate the targets. The ROI method proposed only process the region of target, which can reduce the time-consuming, and it can solve the problem that none or less feature points of the target is detected in 3D reconstruction. We make a dataset of the experimental car and use YOLOv2 to train the dataset, by which the training model of the experimental car is obtained; then the trained model is used to detect the experimental car in the video data which acquired by two USB cameras and get the ROI of the moving target. According to the triangulation method, only the ROI of the image data at the same time is reconstructed, and the average of the obtained coordinates as the position of the car at that moment. In the experiment, we use the positions obtained by optitrack system as the true values, and compare the positions got by the method of this paper (ROI method) with the true value. The experimental results show that the ROI method proposed can be used to locate the dynamic target with the positioning accuracy at the cm level.

UWB (Ultra-wideband) technology is a very promising indoor positioning method because of the advantages of anti-multipath and high precision. For UWB positioning, at least three distance measurements between the base station and a mobile station are required. In practical applications, the signal loss of base stations often occurs due to occlusion and other factors, then resulting in the failure of positioning. To solve this problem, a tightly-coupled method which combines UWB range and measurements of MIMU (Micro Inertial Measurement Unit) is proposed in this paper. The integration positioning system can work continuously during the loss of UWB signals with advantages of INS (Inertial Navigation System) technology’s autonomy and high precision in a short time. A tightly-coupled filter based on EKF (Extended Kalman Filter) is designed, and the integration system is implemented. The simulation based on Matlab and experiments in the indoor testing scene based on the Optitrack system are carried out respectively. The results show that the UWB/MIMU tightly-coupled system can solve the problem of positioning discontinuity caused by signal loss of UWB base stations, and the precision of dynamic positioning is better than 0.3 meters in complex indoor environments.

This paper investigates and proposes a low-precision Micro Inertial Measurement Unit (MIMU)/Ultra-Wideband (UWB) integrated positioning scheme, which aims at realizing indoor high-precision and high-stability localization. A loosely-coupled MIMU/UWB integrated positioning system based on position measurements is designed. Considering three possible cases in practical uses—normally working, UWB signal blockage and UWB gross error occurring, we establishes the simulation platform and the experimental environment to analyze and verify the performance of the integrated system. Simulation and indoor kinematic experimental results show that the MIMU/UWB integrated positioning system produces continuous and accurate position within an error of 2 m. It is also proved to have better continuity and robustness than both independent subsystems.

Measurement and control software of super-station is the core part of super-station and it is also the important part of realizing super-station function. Aiming at the functional characteristics of the super-station, this paper designs the measurement and control software of the super-station and implements it by programming, focusing on the three aspects of the design requirements of the super-station. The interface connection between the measurement and control software and each unit of the super-station is solved in the design. In the aspect of the realization of measurement and control function, the design scheme and flow chart are defined, and the control instruction analysis and interface design are carried out. In the database module, by transplanting FATFS file system, the operation of adding, deleting, modifying and checking measurement data can be realized in the form of files. Finally, we summarize the main work and shortcomings of the design.

This paper introduces in detail methods about calibration length baseline based on μ-base distance meter, and errors in the calculation of oblique distance model; the measurement of meteorological parameters and the correction of height difference are analyzed quantitatively by means of equation derivation. Through the calibration results of μ-base and invar tape, systematic differences between the two measurement methods were found out at the Yellow River Embankment Length Baseline in Zhengzhou. Based on a TS30 total station instrument with stable performance, according to the calculation results of "analytical method" and "comparative method", the accuracy of the two calibration results between μ-base and invar tape is compared and evaluated. In the end, some suggestions to improve the accuracy of using μ-base to calibrate length baseline are given.

It's generally agreed that using a PLL-based frequency control loop for a silicon micromechanical gyroscope the drive frequency can track the natural frequency precisely in any condition. To verify it, an analysis of its frequency tracking ability in varying temperature condition is presented. Firstly the dynamical analysis of the drive mode is presented and its phase-frequency relation is obtained. By analyzing the PLL-based frequency control loop the phase condition for frequency tracking is established. Then the simulation for the relation between the phase drift with temperature of the displacement readout circuit and the drive frequency of the gyroscope is carried out under the fixed phase condition. It shows that the frequency error will increase when the phase drift of the displacement readout circuit is increasing. Finally an experiment is carried out with a digital-analog mixed PCB based on FPGA, which is designed to simultaneously measure the drive frequency, natural frequency and phase drift of displacement readout circuit in temperature ranging from 5°C to 50°C. The results show that the phase of the displacement readout circuit drifts with temperature, and the error between natural frequency and drive frequency is proportional with the phase drift. Thus in order to keep the frequency tracking accuracy in different temperature the compensation for the phase condition must be employed.