Search

Due to technology and safety limitations, the amount of coal resources overlying slopes in open pit coal mines is immense. In recent years, this problem has gradually attracted the attention of researchers. How to realize the efficient recovery of the side overburden resources with the premise of ensuring the stability and safety of the slope has become an important topic for the development of opencast mining technology in China. To study the yield failure characteristics of coal pillars and the rock mass migration law of the end slope mining field under the mining condition of the end slope shearer, 2D/3D, integrated, simulation experimental equipment is developed based on similarity theory and efficient region theory. This equipment overcomes the technical problem that the internal failure of the rock mass is invisible and that deformation data are not easily obtained during the simulation of end slope coal mining on an existing experimental platform. Based on the engineering geological conditions of the Ordos mining area in China, a typical engineering geological model of the slope near the horizontal condition is constructed to simulate the process “formation of mining cave group -failure of support coal pillars - instability of slope rock mass”. Based on laser positioning technology and multiangle, oblique photography technology, a panoramic phase 3D laser scanner, high-resolution digital camera and deep space micromonitoring system are comprehensively employed to carry out the whole process tracking monitoring and analysis of the deformation and failure of the supporting coal pillars and slope rock mass. The experiment is verified by numerical simulation. The results show that under the experimental conditions, with an increase in mining cave depth, the vertical stress of the supporting coal pillar increases linearly. At a certain distance before reaching the end of the mining cave, the peak value is reached. At this time, the depth continues to increase, and the stress value decreases sharply. The vertical stress gradually decreases to the original rock stress after a certain distance beyond the end of the mining cave. A certain length of supporting coal pillar from the end of the mining cave will never collapse, which is approximately 2.5~3 times the width of the mining cave. The triggering condition of slope deformation and failure is under the combined action of dynamic and static loads. The actual stress of the supporting coal pillar in the deep part of the geometric centre along the slope of the mining cave group is greater than the ultimate stress, and then large discontinuous deformation of multiple adjacent coal pillars around the central coal pillar is caused by compressive shear failure. The boundary of the final collapse plane range of the roadway group is approximately a closed curve formed by two paraboloids, which are axisymmetric with the No. Ⅳ coal pillar and open opposite. The parabola opening in the shallow part of the slope area is small, and the parabola opening in the deep part of the slope area is large. There is a significant space-time correspondence between the failure of supporting coal pillars and the deformation of the slope surface. According to the failure process of the rock mass structure and the movement and deformation characteristics of the slope surface, the slope after failure can be divided into three areas, and the upper part of the slope is the key area of deformation and instability of the overlying rock mass in the end-slope mining field. The research results provide a theoretical basis for scientific monitoring and stability control of slope deformation coal mining conditions in open-pit mines.

Objective: This study proposed an innovative approach to simplify the multiple psychological scales for children and adolescents by integrating statistical methods and item reflection theory into a structural equation model. Methods: First, a psychological scale for adolescents to replace the existing scales optimized for adults with the Delphi method has been developed. Second, the number of items in the current group of scales has been reduced. Result and Conclusion: A psychological scale for adolescents has been built up that comprehensively reflects their psychological characteristics in terms of mental state, behavioral status, emotion & feeling, relationship, and environmental adaptation. This psychological scale has been simplified and improved its reliability and validity.

Composites have been widely used in the field of acoustics due to their extraordinary ability of sound insulation. To date, the design of acoustic composites relies primarily on the expertise of engineers and experimental tests. This preliminary study outlines a deep learning (DL) based approach to optimize the microstructure of the composite bars to achieve the best performance in sound insulation. This approach first trains DL networks using data generated using finite element simulation to predict the pressure amplitude and energy of the output waves, then a genetic algorithm (GA) uses the DL model as its evaluation function and generates new designs. The results indicate that a combination of DL and GA can generate Pareto-optimal designs to satisfy the specific needs of engineering projects. We demonstrate that starting with a quite small data set (less than of all possible designs) and applying a DL approach is an efficient and robust method to obtain optimal designs. The DL model is accurate in its predictions which enables the GA to find unique composite designs that are optimal for sound insulation.

Epidural spinal cord stimulation (ESCS) is widely used for chronic pain treatment, and is also a promising tool for restoring motor function after spinal cord injury. Despite significant positive impact of ESCS, currently available protocols provide limited specificity and efficiency partially due to the limited number of contacts of the leads and to the limited flexibility to vary the spatial distribution of the stimulation field in respect to the spinal cord. Recently, we introduced Orientation Selective (OS) stimulation strategies for deep brain stimulation, and demonstrated their selectivity in rats using functional MRI (fMRI). The method achieves orientation selectivity by controlling the main direction of the electric field gradients using individually driven channels. Here, we introduced a similar OS approach for ESCS, and demonstrated orientation dependent brain activations as detected by brain fMRI. The fMRI activation patterns during spinal cord stimulation demonstrated the complexity of brain networks stimulated by OS-ESCS paradigms, involving brain areas responsible for the transmission of the motor and sensory information. The OS approach may allow targeting ESCS to spinal fibers of different orientations, ultimately making stimulation less dependent on the precision of the electrode implantation.

Graphical abstract, Traditional Chinese Medicine (TCM) is a medical science and cultural heritage empirically applied and reserved by Chinese people for thousands of years. With comprehensive prosperity of China and rapid elaboration of technology, healthcare status of Chinese people has become one of the most crucial concerns of the country. Nearly 30 policies and measures regarding TCM development have been issued since the 18th National Congress of the Communist Party of People’s Republic of China in 2012. This review introduced a detailed evolutionary course of TCM in China with an emphasis on understanding the roadmap of TCM related policies and measures in China.

Due to its multiple applications, elastic metamaterial is of great interest for researchers today. In this article, in-plane wave propagation in 2-D anisotropic metamateials with anisotropic density and anisotropic Young’s modulus is comprehensively studied. Characteristics of wave propagation in 2-D metamaterial with different combinations of negative properties are provided, and the unnatural phenomenon is also explained. Based on Snell’s law and weld boundary condition, analysis of wave propagation from conventional isotropic material into anisotropic metamaterial is performed. This paper can serve as a foundation for future study of massive modeling and simulation of both isotropic and anisotropic metamaterials.

In this paper, a design of active elastic metamaterial that possesses negative density and tunable bulk modulus is presented for the negative refraction of in-plane elastic waves at deep subwavelength scale. The metamaterial is fabricated in an aluminum plate, and the resonant structure in a unit cell of the metamaterial composes of a coated steel that functions as a translational resonator and a radially polarized piezoelectric transducer shunted with negative capacitance. Based on effective continuum theory, the effective mass density and bulk modulus are numerically determined. The passive and active elements work together to generate broad band double-negative material properties. Simulation results verified and demonstrated the negative refraction of elastic waves at the interface between proposed elastic metamaterials and natural solids. The proposed elastic metamaterial may thus be used as a flat lens with broad working frequency regime for in-plane elastic wave focusing.

This article presents a comprehensive study of two-dimensional acoustic metamaterial based on mass-in-mass lattice model with both one resonator and multi-resonators. We demonstrate the dynamic anisotropic property of a two-dimensional lattice system and the existence of multiple stop bands of mass-in-mass lattice systems with more than one resonator. A two-dimensional stable lattice plate structure, composed of unit mass-in-mass cells is proposed, and been studied by adapting both an exact model and a continuum model. The dispersion surfaces and stop band obtained by the exact model show that the stop band of this metamaterial exists, and it can be shifted and operated upon. In contrast, the dispersion surface obtained through the continuum model describes the acoustic mode well, but is only accurate at low frequencies for the optical mode. By attaching a secondary resonator to the primary resonator, an additional stop band is achieved. Finally, an acoustic metamaterial plate which has more than one stop band is proposed and studied numerically. Good agreement has been achieved between theoretical and numerical analyses.

In this paper, an elastic metamaterial is proposed by integrating a two-dimensionally periodic honeycomb lattice and tetrachiral metamaterial inclusions for low-frequency wave applications. Plane wave propagation in infinite periodic cells is investigated through using Floquet–Bloch principles and the finite element method. Two separate negative pass bands induced by different mechanisms appear in the band structures of wave propagation in the proposed elastic metamaterial. The working mechanisms of those two negative pass bands are revealed though analyzing the eigenmodes of the unit cell and the dynamic effective material properties. Numerical examples validate the proposed model and show that negative refraction of elastic waves in the elastic metamaterial has been obtained. The design concept of this type of elastic may be of use for the design of broadband flat lenses for elastic wave focusing.

In this paper, we propose and study a single-phase elastic metamaterial with periodic chiral local resonator, which is composed of cylindrical central core surrounded by evenly distributed ligaments and embedded in the matrix in a square lattice. Based on the analytical and numerical analysis, we prove that the translational resonance of the unit cell can lead to negative effective mass density, and the rotational resonance of it can produce negative effective modulus. They can also work together to generate double-negative effective material properties. The wave attenuation of elastic waves in this elastic metamaterial is also demonstrated, which is owing to the negative effective mass density. In addition, the damping of the base material is also considered in the simulation. We finally examine the existence of negative band, and this leads to the physics of negative refraction, which is induced by simultaneous translational and rotational resonance of the unit cell. Our work can serve as the theoretical foundation for the design of single-phase elastic metamaterials.

GuangZao and RouDouKou (Fructus Choerospondiatis and Nutmeg, FCN) are one of the most common herb pairs in traditional Mongolian medicine for the treatment of coronary heart disease (CHD). However, evidence for the protective effect of FCN is limited, and its underlying mechanism of action remains unclear. The present study employed a network pharmacology approach to identify the potentially active ingredients and synergistic effects of the herb pair FCN as traditional Mongolian medicine. We predicted the targets of all available FCN ingredients with PharmMapper, SWISS, and SuperPred Server and clustered CHD-related targets from the DrugBank and the OMIM database. We also evaluated the links between herbal ingredients and pharmacological actions to explore the potential mechanism of action of FCN. We found that FCN targets a network of CHD-related key processes, including stress responses, cell adhesion and connections, angiogenesis, cell apoptosis and necrosis, the endocrine system, inflammatory and immune responses, and other biological processes. To confirm the predicted results, we investigated the protective effect of FCN on isoproterenol- (ISO-) induced myocardial ischemia in rats. Pathological assessment indicated that FCN inhibits apoptosis and inflammatory responses involving the myocardium. Quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting analyses demonstrated the therapeutic effects of FCN on ISO-induced myocardial ischemia rats, possibly via regulating stress and inflammatory responses and inhibiting cardiomyocyte apoptosis. The findings of the present study indicate that bioinformatics combined with experimental verification provide a credible and objective method to elucidate the complex multitarget mechanism of action of FCN.

Vector space model using bag of phrases plays an important role in modeling Chinese text. However, the conventional way of using fixed gram scanning to identify free-length phrases is costly. To address this problem, we propose a novel approach for key phrase identification which is capable of identify phrases with all lengths and thus improves the coding efficiency and discrimination of the data representation. In the proposed method, we first convert each document into a context graph, a directed graph that encapsulates the statistical and positional information of all the 2-word strings in the document. We treat every transmission path in the graph as a hypothesis for a phrase, and select the corresponding phrase as a candidate phrase if the hypothesis is valid in the original document. Finally, we selectively divide some of the complex candidate phrases into sub-phrases to improve the coding efficiency, resulting in a set of phrases for codebook construction. The experiments on both balanced and unbalanced datasets show that the codebooks generated by our approach are more efficient than those by conventional methods (one syntactical method and three statistical methods are investigated). Furthermore, the data representation created by our approach has demonstrated higher discrimination than those by conventional methods in classification task.

In this paper, we proposed a type of local resonator which works by introducing more than one vibration modes, and thus may provide a new approach to formulate acoustic/elastic metamaterial. Such new concept of resonator is fundamentally different from traditional translational and rotational resonators. The potential application and design of acoustic/elastic metamaterial based on this kind of structures are also illustrated. The acoustic metamaterial filter we developed has unique property that only the waves with specific frequency can pass the material while other waves will be attenuated. We also proposed a kind of plane wave lens which can transfer plane wave with uniformly distributed amplitude profiles into pure plane wave. With these novel resonators, the research and application regarding it are highly anticipated in the near future.

In this paper, we proposed a type of locally resonator which works by introducing more than one vibration modes, and thus can provide a new approach to formulate acoustic or elastic metamaterial. Such new concept of resonator is fundamentally different from traditional translational and rotational resonators. The potential application and design of acoustic metamaterial based on this kind of structures are also studied both analytically and numerically. The acoustic metamaterial filter we developed has proved to have unique property that only allow the waves with specific frequency to pass while other waves will be attenuated. We also proposed a kind of plane wave lens which can transfer plane wave with uniformly distributed amplitude profiles into pure plane wave. With this novel resonator, the research and application regarding it are highly anticipated in the near future.

The processing technology of traditional Mongolian medicine materials is distinctive, and it is one of the main characteristics of Mongolian pharmacy. Most of Mongolian medicines were used in the raw, but a quarter of medicinal materials need to be produced. Since ancient times, the processing of Mongolian medicine have cooperated with the Mongolian medicine clinical, which plays an important role in improving curative effect of Mongolian medicine and ensuring the safety of the drug. At present, the Mongolian medicines are processed still according to the traditional methods of the ancient literature method which has a lot of problems such as lag in technology, method of diversification, ambiguous indicators and unclear mechanism. Standardization of Mongolian medicine processing was based on traditional Mongolian medicine basic theory, which both projecting the characteristic, inheriting the traditional colleagues and reference to modern medicine, pharmacology, toxicology and other disciplines of knowledge. In this article, the processing situation, existing problem and standardization research of Mongolian medicine were described that providing a reference for the modernization and standardization of Mongolian medicine.

The effects of effective part group on hyperlipidemia in animal were studied. The SD rats, hamsters and Kunming mouse were divided into blank group, model group. The positive control group and test group were fed with normal diet, blank and other groups were fed with high fat diet (mouse only a single intraperitoneal injection of egg yolk ). The corresponding concentration of solvent, simvastatin, effective part group of emulsion were given gavage once daily. The animal serum total cholesterol (TC) , triglyceride (TG) , low density lipoprotein (LDL) , high density lipoprotein (HDL) and liver TC, TG contents were determined to observe the effects of the effective fractions on blood lipid regulating function. Comparing with control group, the animial hyperlipidemia models of the SD rat (TC increase), mouse (TC, TG, LDL increase), hamsters ( TC, TG, LDL increase, HDL decrease) (P0. 05, P0. 001) were successfully established. Piper longum effective part group could decrease the serum TC, TG, LDL (P0.05, P0. 001) and liver TC, TG content, and elevate serum HDL levels (P0.05, P0.001). The golden hamster is ideal for hyperlipidemia model.

This article reveals the similarities and differences between the two materia medica systems of traditional Chinese medicine and traditional Mongolian medicine by comparing the medicinal property theories of these two; our expectations are the mutual profits and complementation of the two traditional medicines from each other, a broader clinical use of natural medicinal herbs, and then, a development of traditional medicines.