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Quickly determining the metal content in plants and subsequently identifying geochemical anomalies can provide clues and guidance for predicting the location and scale of concealed ore bodies in vegetation-covered areas. Although visible, near-infrared and shortwave infrared (VNIR–SWIR) reflectance spectroscopy at wavelengths ranging from 400 to 2500 nm has been proven by many researchers to be a fast, accurate and nondestructive approach for estimating the contents of copper (Cu), lead (Pb), zinc (Zn) and other metal elements in plants, relatively few studies have been conducted on the estimation of lithium (Li) in plants. Therefore, the potential of applying VNIR–SWIR spectroscopy techniques for estimating the Li content in plants was explored in this study. The Jingerquan Li mining area in Hami, Xinjiang, China, was chosen. Three sampling lines were established near a pegmatite deposit and in a background region, canopy reflectance spectra were obtained for desert plants and Li contents were determined in the laboratory; then, quantitative relationships were established between nine different transformed spectra (including both integer and fractional orders) and the Li content was estimated using partial least squares regression (PLSR). The results showed that models constructed using high-order derivative spectra (with an order greater than or equal to 1) significantly outperformed those based on original and low-order derivative spectra (with an order less than 1). Notably, the model based on a 1.1-order derivative spectrum displayed the best performance. Furthermore, the performance of the model based on the two-layer wavelet coefficients of the 1.1-order derivative spectrum was further improved compared with that of the model based on only the 1.1-order derivative spectrum. The coefficient of determination (Rpre2) and the ratio of performance to deviation (RPD) for the validation set increased from 0.6977 and 1.7656 to 0.7044 and 1.8446, respectively, and the root mean square error (RMSEpre) decreased from 2.5735 to 2.4633 mg/kg. These results indicate that quickly and accurately estimating the Li content in plants via the proposed spectroscopic analysis technique is feasible and effective; however, appropriate spectral preprocessing methods should be selected before hyperspectral estimation models are constructed. Overall, the developed hybrid spectral transformation approach, which combines wavelet coefficients and derivative spectra, displayed excellent application potential for estimating the Li content in plants.

This article presents the numerical solutions of nonlinear stochastic It o^–Volterra integral equations by using the basis function method under the global Lipschitz condition. Integral operator matrixes of triangular functions are used to convert the nonlinear stochastic integral equations into a system of algebraic equations. Meanwhile, we gain the error of the current method, and it is demonstrated that the error accuracy of this method is higher than that of the BPFs. In the end, the feasibility, accuracy, and validity of the current method are demonstrated by numerical results.

Rock geochemical methods are effective for geological surveys, but typical sampling and laboratory-based analytical methods are time-consuming and costly. However, using visible–near-infrared spectroscopy to estimate the metal element content of rock is an alternative method. This study discussed the potential of hyperspectral estimation of Cu and its significant associated elemental content. Ninety-five rock samples were collected from the Kalatage Yudai copper–nickel deposit in Hami, Xinjiang. The effects of different spectral resolutions, spectral preprocessing, band indices, and characteristic band selection on the estimation of the element contents of Fe, Cu, Co, and Ti were investigated. The results show that when the spectral resolution is 5 nm, good results are obtained for all four metal elements, Fe, Cu, Co, and Ti, with the coefficients of determination R2 reaching 0.54, 0.59, 0.41, and 0.78, respectively. The best results are obtained for all transformed spectra with continuum removal, inverse transformation, continuum removal, and logarithmic transformation, respectively. In addition, the accuracy of the estimation models constructed by combining band indices and feature band selection was superior compared with full-band spectra for Fe (R2 = 0.654, MAE = 1.27%, and RPD = 1.498), Cu (R2 = 0.694, MAE = 20.509, and RPD = 1.711), Co (R2 = 0.805, MAE = 2.573, and RPD = 2.199), and Ti (R2 = 0.501, MAE = 0.04%, and RPD = 1.412). The results indicate that using band indices can provide a more accurate estimation of metal element content, providing a new technical method for the efficient acquisition of regional mineralization indicator element content distribution.

Abstract In this paper, an efficient numerical method is presented for solving nonlinear stochastic Itô–Volterra integral equations based on Haar wavelets. By the properties of Haar wavelets and stochastic integration operational matrixes, the approximate solution of nonlinear stochastic Itô–Volterra integral equations can be found. At the same time, the error analysis is established. Finally, two numerical examples are offered to testify the validity and precision of the presented method.

This paper presents a valid numerical method to solve nonlinear stochastic Itô–Volterra integral equations (SIVIEs) driven by fractional Brownian motion (FBM) with Hurst parameter H∈1/2,1. On the basis of FBM and block pulse functions (BPFs), a new stochastic operational matrix is proposed. The nonlinear stochastic integral equation is converted into a nonlinear algebraic equation by this method. Furthermore, error analysis is given by the pathwise approach. Finally, two numerical examples exhibit the validity and accuracy of the approach.

Experimental learning is one kind of contextual learning, which places learners in a variety of virtual or real contexts to acquire knowledge, gain ability and experience, and generates emotion through experiencing and perceiving, communicating and exploring, and self-reflecting. Applying VR technology to experiential learning involves both technology and teaching. Based on the Learning Pyramid, Constructivist Learning Theory, and the characteristics of virtual technology, this study proposes a theoretical model of virtual reality experiential learning, which takes the international business negotiation scene as an example and employs such software as 3Ds Max and VR-platform to implement an experiential learning context. It is found that, compared with traditional teaching, this learning context has effectively increased the learners' memorization and understanding ability, their interest and motivation in learning, enhanced their learning experience and improved the learning effects. This study not only provides a theoretical framework for and verifies the promotion effect of virtual technology on learners but also enriches the research examples of virtual reality experiential learning, which has certain theoretical value and practical significance.

Detritus geochemical information has been proven through research to be an effective prospecting method in mineral exploration. However, the traditional detritus metal content monitoring methods based on field sampling and laboratory chemical analysis are time-consuming and may not meet the requirements of large-scale metal content monitoring. In this study, we obtained 95 detritus samples and seven HySpex hyperspectral imagery scenes with a spatial resolution of 1 m from Karatag Gobi area, Xinjiang, China, and used partial least squares and wavebands selection methods to explore the usefulness of super-low-altitude HySpex hyperspectral images in estimating detritus feasibility and effectiveness of Cu element content. The results show that: (1) among all the inversion models of transformed spectra, power-logarithm transformation spectrum was the optimal prediction model (coefficient of determination(R2) = 0.586, mean absolute error(MAE) = 21.405); (2) compared to the genetic algorithm (GA) and continuous projection algorithm (SPA), the competitive weighted resampling algorithm (CARS) was the optimal feature band-screening method. The R2 of the inversion model was constructed based on the characteristic bands selected by CARS reaching 0.734, which was higher than that of GA (0.519) and SPA (0.691), and the MAE (19.926) was the lowest. Only 20 bands were used in the model construction, which is lower than that of GA (105) and SPA (42); (3) The power-logarithm transforms, and CARS combined with the model of HySpex hyperspectral images and the Cu content distribution in the study area were obtained, consistent with the actual survey results on the ground. Our results prove that the method incorporating the HySpex hyperspectral data to invert copper content in detritus is feasible and effective, and provides data and a reference method for obtaining geochemical element distribution in a large area and for reducing key areas of geological exploration in the future.

For characteristics that power supplys in coal mine underground has multi input voltage grades and are susceptible to disturbed when big equipments are starting or stopping, the paper put forward a design scheme of adaptive wide-voltage power supply with explosion-proof and intrinsic safety. The power supply uses intelligent phase shift voltage regulating technology and wide-voltage switching power supply technology, and adopts single-chip microcomputer to realize automatic identification of high and low voltage section, automatic switch, intelligent phase shift voltage regulating of 85-825 V wide input voltage, and uses PWM to convert fluctuant voltage to a stable DC voltage. The experiment results show that the scheme solves problems of multi voltage grades and wide-voltage fluctuation of mine-used power supply.

The aim of this study was to investigate whether Huisheng Oral Solution has an anticoagulant effect in a rat model of thrombosis. Forty male SD rats were equally and randomly divided into four groups: blank group, model group, and two treatment groups (A and B). Rats were subcutaneously injected with carrageenan to induce thrombosis. Rats in treatment group A were intragastrically administered with Huisheng Oral Solution in a dose of 2 mL/100 g body weight (once per 8 h) 72 h after carrageenan injection, and those in treatment group B both 72 h before and after the induction of thrombosis. Blood samples were collected 24, 48, and 72 h after carrageenan injection for measurements of prothrombin time (PT), activated partial thromboplastin time (APTT), international normalized ratio (INR), fibrinogen (FIB), prothrombin activity (PTA), platelets (PLT), fibrin degradation products (FDPs), and D-dimer. Lung, liver and mesentery samples were taken 72 h after carrageenan injection for histopathological analysis. The number of microthrombi in sections of different tissue samples were counted under a microscope. Blood parameters among each group were compared using the Welch test, Kruskal-Wallis test or SNK test after testing for normality, while the number of microthrombi was compared using the Bonferroni test. Compared to the model group, PT, APTT, INR, and FIB levels at the majority of time points were significantly shorter or lower in the two treatment groups (P

A multi-user broadcast authentication scheme was proposed in wireless sensor networks with defending against DoS attacks（DDA-MBAS） based on vBNN-IBS signature,the bogus messages could be filtered using hash op-eration and user information.Compared with existing multi-user broadcast authentication schemes,except defending against node compromise attack and active attack,the bogus messages can be filtered with low energy consumption and the threat of DoS attack and collusion attack launched by compromised user can be limited effectively.

For normal use of water supply rescue system, the paper designed a monitoring system of mine water supply pipeline. The system can real-timely monitor parameters of pipeline flow, pressure, temperature and others through sensor, and transmit collected data to monitoring substation. Meanwhile, the monitoring substation can real-timely upload monitoring data to main and standby monitoring computer which makes analysis of received data to determine whether pipeline is abnormal, and saves the finished form data, forms reports and curve analysis for decision makers. The practical application showed that the system is stable in running and reliable in operation and can reflect true underground hydrology, which provides reliable basis for water supply rescue system.

The paper analyzed characteristics of images of obstacle in front of running locomotive obtained by camera of anti-collision system of mine locomotive, and proposed recognition methods of obstacle away from the locomotive with short, middle and long distances and their realization flows. The testing result showed the method can obtain characteristics of obstacles validly and recognize the obstacles quickly.