Application of Mine Micro-Seismic Monitoring System on Preventing Against Illegal Mining

AbstractThe establishment and application of the Mine Micro-seismic Monitoring System (MMS), provides a powerful method not only to monitor and predict the mine geological hazard, but also to monitor and prevent against the illegal mining. While there was illegal mining, the system can give you the information including the 3-dimensional spatial coordinates in real time.. The monitoring against the illegal mining was aimed at the blast events, so the blast events should be collected and analyzed specially. On the other hand, the energy of the blast events are larger enough to be easily recognized and be 3-d located and then be analyzed by the MMS, and then the satisfied information can be given by the MMS. This kind of usage of the system has been analyzed and confirmed by a practical example

Direct measurement of the Raman enhancement factor of rhodamine 6G on graphene under resonant excitation

Graphene substrates have recently been found to generate Raman enhancement. Systematic studies using different Raman probes have been implemented, but one of the most commonly used Raman probes, rhodamine 6G (R6G), has yielded controversial results for the enhancement effect on graphene. Indeed, the Raman enhancement factor of R6G induced by graphene has never been measured directly under resonant excitation because of the presence of intense fluorescence backgrounds. In this study, a polarization-difference technique is used to suppress the fluorescence background by subtracting two spectra collected using different excitation laser polarizations. As a result, enhancement factors are obtained ranging between 1.7 and 5.6 for the four Raman modes of R6G at 611, 1,183, 1,361, and 1,647 cm[superscript −1] under resonant excitation by a 514.5 nm laser. By comparing these results with the results obtained under non-resonant excitation (632.8 nm) and pre-resonant excitation (593 nm), the enhancement can be attributed to static chemical enhancement (CHEM) and tuning of the molecular resonance. Density functional theory simulations reveal that the orbital energies and densities for R6G are modified by graphene dots.National Natural Science Foundation (China) (Nos. 21233001, 50972001, and 21129001)China. Ministry of Science and Technology (Nos. 2011YQ0301240201 and 2011CB932601)Beijing Natural Science Foundation (No. 2132056

Experimental Study on Failure Mode of Concrete Beams Strengthened with FRP Sheet

The failure mode of the FRP reinforced concrete beam with different sheet length was investigated by experiments. The results indicate that, more cracks distributed on the bottom of the beam in the failure process of the FRP reinforced concrete structure. The effect of the FRP sheet length is considered to be an important factor not only to significantly influence the loading capacity but also to control the maximum deflection of the concrete beam. In addition, the loading capacity is increased and maximum deflection of the concrete beam is also increased with the increasing of the FRP sheet length. It showed that FRP strengthened beams failed prematurely in a brittle and sudden manner due to debonding between FRP and concrete substrate and therefore the full strength of the FRP sheet cannot be sufficiently utilized

Experimental Study on Failure Mode of Concrete Beams Strengthened with FRP Sheet

The failure mode of the FRP reinforced concrete beam with different sheet length was investigated by experiments. The results indicate that, more cracks distributed on the bottom of the beam in the failure process of the FRP reinforced concrete structure. The effect of the FRP sheet length is considered to be an important factor not only to significantly influence the loading capacity but also to control the maximum deflection of the concrete beam. In addition, the loading capacity is increased and maximum deflection of the concrete beam is also increased with the increasing of the FRP sheet length. It showed that FRP strengthened beams failed prematurely in a brittle and sudden manner due to debonding between FRP and concrete substrate and therefore the full strength of the FRP sheet cannot be sufficiently utilized

In-plane uniaxial strain in black phosphorus enables the identification of crystalline orientation

The identification of the crystalline axis of anisotropic black phosphorus (BP) is key for the study of its physical properties and for its optical and electronic applications. Herein, we show that by applying an in-plane uniaxial strain and measuring the changes of Raman shifts, the crystalline axis of BP can be reliably determined. The strain effects on Raman shifts are angle-dependent, which can be expressed as a combination of Raman responses under zigzag and armchair strains. Different from previous polarized optical spectroscopic means, the proposed method does not rely on the laser polarization, the excitation wavelength, the sample thickness and the material of the stretchable substrate. Besides, the effective strain applied on BP from the stretched substrate is estimated, showing that only 20% to 40% of the strain can be effectively transferred to BP flakes from polyethylene terephthalate substrates. Our method provides not only an effective and universal approach to identify the crystalline orientation of layered BP, but also a model to extract additional information in strain-related studies, and can be extended to other 2D anisotropic materials.Comment: 28 pages, 10 figures. There are some incorrect description would cause misunderstandin

Graphene-Thickness-Dependent Graphene-Enhanced Raman Scattering

Graphene-enhanced Raman scattering (GERS), enhancing Raman signals on graphene surface, is an excellent approach to investigate the properties of graphene via the Raman enhancement effect. In the present study, we studied the graphene-thickness dependent GERS in detail. First, by keeping molecule density on few-layer graphene using vacuum thermal deposition method, GERS enhancement was found to be the same for all graphene layers (one to six layers). While adsorbing probe molecules by solution soaking, the GERS enhancing factor was different on monolayer and bilayer graphene. By soaking in low concentration solutions, the GERS intensity on bilayer graphene was stronger than that on monolayer graphene, whereas by soaking under high concentration solutions, the GERS intensity difference was much less for that on monolayer and on bilayer. Molecule density, molecular configuration, and GERS enhancing factor are further discussed for molecules on monolayer and bilayer graphene. It was finally concluded that the abnormal graphene-thickness dependence of GERS between monolayer and bilayer graphene was attributed to the different enhancement for GERS on monolayer and bilayer graphene. Monolayer and bilayer graphene have different electronic structure and then doping effect of probe molecules, which shifts the Fermi level of graphenes differently. As a result, monolayer and bilayer graphene have different energy band matching with the probe molecules, yielding different chemical enhancement

Anomalous Polarized Raman Scattering and Large Circular Intensity Differential in Layered Triclinic ReS₂

The Raman tensor of a crystal is the derivative of its polarizability tensor and is dependent on the symmetries of the crystal and the Raman-active vibrational mode. The intensity of a particular mode is determined by the Raman selection rule, which involves the Raman tensor and the polarization configurations. For anisotropic two-dimensional (2D) layered crystals, polarized Raman scattering has been used to reveal the crystalline orientations. However, due to its complicated Raman tensors and optical birefringence, the polarized Raman scattering of triclinic 2D crystals has not been well studied yet. Herein, we report the anomalous polarized Raman scattering of 2D layered triclinic rhenium disulfide (ReS₂) and show a large circular intensity differential (CID) of Raman scattering in ReS₂ of different thicknesses. The origin of CID and the anomalous behavior in polarized Raman scattering were attributed to the appearance of nonzero off-diagonal Raman tensor elements and the phase factor owing to optical birefringence. This can provide a method to identify the vertical orientation of triclinic layered materials. These findings may help to further understand the Raman scattering process in 2D materials of low symmetry and may indicate important applications in chiral recognition by using 2D materials

Selective Scission of C–O and C–C Bonds in Ethanol Using Bimetal Catalysts for the Preferential Growth of Semiconducting SWNT Arrays

For the application of single-walled carbon nanotubes (SWNTs) to electronic and optoelectronic devices, techniques to obtain semiconducting SWNT (s-SWNT) arrays are still in their infancy. We have developed herein a rational approach for the preferential growth of horizontally aligned s-SWNT arrays on a ST-cut quartz surface through the selective scission of C–O and C–C bonds of ethanol using bimetal catalysts, such as Cu/Ru, Cu/Pd, and Au/Pd. For a common carbon source, ethanol, a reforming reaction occurs on Cu or Au upon C–C bond breakage and produces C_ads and CO, while a deoxygenating reaction occurs on Ru or Pd through C–O bond breaking resulting in the production of O_ads and C₂H₄. The produced C₂H₄ by Ru or Pd can weaken the oxidative environment through decomposition and the neutralization of O_ads. When the bimetal catalysts with an appropriate ratio were used, the produced C_ads and C₂H₄ can be used as carbon source for SWNT growth, and O_ads promotes a suitable and durable oxidative environment to inhibit the formation of metallic SWNTs (m-SWNTs). Finally, we successfully obtained horizontally aligned SWNTs on a ST-cut quartz surface with a density of 4–8 tubes/μm and an s-SWNT ratio of about 93% using an Au/Pd (1:1) catalyst. The synergistic effects in bimetallic catalysts provide a new mechanism to control the growth of s-SWNTs

Nodule-specific cysteine-rich peptide 343 is required for symbiotic nitrogen fixation in Medicago truncatula

Symbiotic interactions between legumes and rhizobia lead to the development of root nodules and nitrogen fixation by differentiated bacteroids within nodules. Differentiation of the endosymbionts is reversible or terminal, determined by plant effectors. In inverted repeat lacking clade legumes, nodule-specific cysteine-rich (NCR) peptides control the terminal differentiation of bacteroids. Medicago truncatula contains ∼700 NCR-coding genes. However, the role of few NCR peptides has been demonstrated. Here, we report characterization of fast neutron 2106 (FN2106), a symbiotic nitrogen fixation defective (fix−) mutant of M. truncatula. Using a transcript-based approach, together with linkage and complementation tests, we showed that loss-of-function of NCR343 results in impaired bacteroid differentiation and/or maintenance and premature nodule senescence of the FN2106 mutant. NCR343 was specifically expressed in nodules. Subcellular localization studies showed that the functional NCR343-YFP fusion protein colocalizes with bacteroids in symbiosomes in infected nodule cells. Transcriptomic analyses identified senescence-, but not defense-related genes, as being significantly upregulated in ncr343 (FN2106) nodules. Taken together, results from our phenotypic and transcriptomic analyses of a loss-of-function ncr343 mutant demonstrate an essential role of NCR343 in bacteroid differentiation and/or maintenance required for symbiotic nitrogen fixation

Droxinostat, a Histone Deacetylase Inhibitor, Induces Apoptosis in Hepatocellular Carcinoma Cell Lines via Activation of the Mitochondrial Pathway and Downregulation of FLIP

Background: The current chemotherapeutic outcomes for hepatocellular carcinoma (HCC) are not encouraging, and long-term survival of this patient group remains poor. Recent studies have demonstrated the utility of histone deacetylase inhibitors that can disrupt cell proliferation and survival in HCC management. However, the effects of droxinostat, a type of histone deacetylase inhibitor, on HCC remain to be established. Methods: The effects of droxinostat on HCC cell lines SMMC-7721 and HepG2 were investigated. Histone acetylation and apoptosis-modulating proteins were assessed via Western blot. Proliferation was examined with 3-(4, 5 dimetyl-2-thiazolyl)-2, 5-diphenyl 2H-tetrazolium bromide, cell proliferation, and real-time cell viability assays, and apoptosis with flow cytometry. Results: Droxinostat inhibited proliferation and colony formation of the HCC cell lines examined. Hepatoma cell death was induced through activation of the mitochondrial apoptotic pathway and downregulation of FLIP expression. Droxinostat suppressed histone deacetylase (HDAC) 3 expression and promoted acetylation of histones H3 and H4. Knockdown of HDAC3 induced hepatoma cell apoptosis and histone H3 and H4 acetylation. Conclusions: Droxinostat suppresses HDAC3 expression and induces histone acetylation and HCC cell death through activation of the mitochondrial apoptotic pathway and downregulation of FLIP, supporting its potential application in the treatment of HCC