Search

Coal gangue, which accumulates in the open air, is modified by immersion in rain, and exhibits different tendencies to spontaneous combustion in different areas of precipitation. To study the role and influence of moisture on the oxidation and spontaneous combustion of coal gangue, we used high-sulfur coal gangue prone to spontaneous combustion in the Qipanjing area of Inner Mongolia. First, the coal gangue is soaked with different moisture content (moisture content: 0, 15%, 30%, 50%, 100%). After soaking for 45 days, the coal gangue is naturally air dried. The dried gangue samples were put into the self-made programmed temperature experiment furnace to conduct experiments on the pre-treated coal gangue samples (the temperature rise rate was set at 3℃/min, and the temperature rise range was set at 30−390 ℃). The gas the temperature points of the coal gangue in each stage was collected by air collecting bag (each rise of 15 ℃ was a stage). Finally, the collected gas was passed into the GC-4000A gas chromatograph. By comparing the O2 consumption、the volume fraction of CO, CH4, C2H4, C2H6 and other index gases produced by coal gangue treated with different moisture content, the results show that: The low temperature oxidation of coal gangue is the best when the moisture content is 15%, the initial formation temperature of CO, CH4, C2H4, C2H6 and other indicator gases is the lowest, and the concentration of various indicator gases is the highest when the temperature is 390℃. When the moisture content exceeds 50%, under the action of moisture dissolution, a large number of combustible substances in the coal gangue are carried and dispersed by moisture, resulting in a significant decrease in the concentration of various indicator gases generated when the moisture content of the coal gangue rises to 390 ℃, even lower than that of the control experimental group without moisture immersion and redrying treatment. When the coal gangue is immersed in water, the initial temperature points of the various index gases are reduced by about 15 ℃.

Background: the feasibility of the capacitance method for detecting the water content in standing tree trunks was investigated using capacitance-based equipment that was designed for measuring the water content of standing tree trunks. Methods: In laboratory experiments, the best insertion depth of the probe for standing wood was determined by measurement experiments conducted at various depths. The bark was to be peeled when specimens and standing wood were being measured. The actual water content of the test object was obtained by specimens being weighed and the standing wood being weighed after the wood core was extracted. Results: A forecast of the moisture content of standing wood within a range of 0 to 180% was achieved by the measuring instrument. The feasibility of the device for basswood and fir trees is preliminarily studied. When compared to the drying method, the average error of the test results was found to be less than 8%, with basswood at 7.75%, and fir at 7.35%. Conclusions: It was concluded that the measuring instrument has a wide measuring range and is suitable for measuring wood with low moisture content, as well as standing timber with high moisture content. The measuring instrument, being small in size, easy to carry, and capable of switching modes, is considered to have a good application prospect in the field of forest precision monitoring and quality improvement.

Although growth arrest‐specific protein 2 (GAS2) promotes the growth of T‐cell acute lymphoblastic leukemia (T‐ALL) cells in culture, the effect of GAS2 on T‐cell leukemogenesis has not been studied, and the mechanism remains unclear. In the present study, xenograft studies showed that GAS2 silencing impaired T‐cell leukemogenesis and decreased leukemic cell infiltration. Mechanistically, GAS2 regulated the protein expression of C‐X‐C chemokine receptor type 4 (CXCR4) rather than its transcript expression. Immunoprecipitation revealed that GAS2 interacted with CXCR4, and confocal analysis showed that GAS2 was partially co‐expressed with CXCR4, which provided a strong molecular basis for GAS2 to regulate CXCR4 expression. Importantly, CXCR4 overexpression alleviated the inhibitory effect of GAS2 silencing on the growth and migration of T‐ALL cells. Moreover, GAS2 or CXCR4 silencing inhibited the expression of NOTCH1 and c‐MYC. Forced expression of c‐MYC rescued the growth suppression induced by GAS2 or CXCR4 silencing. Meanwhile, GAS2 deficiency, specifically in blood cells, had a mild effect on normal hematopoiesis, including T‐cell development, and GAS2 silencing did not affect the growth of normal human CD3+ or CD34+ cells. Overall, our data indicate that GAS2 promotes T‐cell leukemogenesis through its interaction with CXCR4 to activate NOTCH1/c‐MYC, whereas impaired GAS2 expression has a mild effect on normal hematopoiesis. Therefore, our study suggests that targeting the GAS2/CXCR4 axis is a potential therapeutic strategy for T‐ALL.

Shape memory materials with controllable property for harsh condition like high temperature are strongly required. Here, three novel shape memory polyimides (SMPIs) have been realized by bearing various side-chain groups (-H, –CH3 or –OCH3) to study their relationship between structures and shape memory performances. These PIs possess excellent shape memory behaviors in both fixity ratio (Rf > 99.1%) and recovery ratio (Rr > 86.8%). The rheological information revealed different creep and stress relaxation accompanied with the different SMPIs. Meanwhile, fractional free volume (FFV) and simulating of geometry optimized molecule chain via Materials Studio were referred to reveal the inner relationship between shape memory performance and polymer structure. This work provides a design metric to guiding significance to the structure design of shape memory polyimides.

PEEK is being used increasingly often in seals, bushings, bearings, and other moving parts due to its excellent mechanical and tribological properties. Herein, PEEK-based composites were prepared using PI as the organic filler and h-BN and nano-SiO2 particles as the inorganic fillers. There was significant improvement in the tribological properties of PEEK at conditions above the glass transition temperature; the coefficient of friction of +20P/4B/4Si was stabilized at 0.06 at 200 °C and the wear rate was reduced by 60% compared to PEEK. The role played by the thermal conductivity of h-BN and the promotion of friction transfer film by nano-SiO2 in improving the tribological properties of PEEK is illustrated. The modified composites exhibited stable mechanical and tribological properties over a wide temperature range, which is instructive for instrumentation and testing applications in harsh environments.

As the adhesive for composites, the resin matrix directly impacts the molding process and product performance of thermoplastic composites (TPCs). Carbon fiber-reinforced polyetherimide (CF/PEI) and polyaryletherketone (CF/PAEK) composites were prepared by a compression molding process. The interface, interlaminar, and low-speed impact properties of TPCs were studied. The results show that the interfacial shear strength of the CF/PEI composite is ~116 MPa, while the CF/PAEK composite is ~78 MPa. However, the interlaminar and low-speed impact performance of CF/PAEK is better than CF/PEI. Type I fracture toughness (GIC) and type II fracture toughness (GIIC) of CF/PEI are ~1051 MPa and ~1060 MPa. But those of CF/PAEK are ~1786 MPa and ~2584 MPa, respectively. The compressive strength after the impact of CF/PAEK (~321 MPa) is 40% higher than CF/PEI (~230 MPa).

Most field scientific observation and research stations are located at the end of power grids which are usually not extended to such areas. Consequently, the power supply of equipment in field observation stations cannot be guaranteed. Meanwhile, regions with poor ecosystem stability are relatively sensitive to environmental changes and thus prone to degradation and succession due to external interference. In this paper, the photovoltaic (PV) power generation system of a grassland ecohydrological field scientific observation and research station was taken as the research object. Two kinds of distributed PV power generation systems were simulated and analyzed by use of PVsyst software. The total power of laboratory equipment, PV power generation efficiency, and system cost of the field observation station were calculated and analyzed. The design scheme and scale of PV power generation systems suitable for field observation stations were determined. Finally, a PV power generation test system was set up, and PV power generation data were sorted out. The feasibility of the design scheme of PV power generation systems was verified by analyzing the relationship between the simulated and actual power generation of systems and that between the daily energy use proportions of field observation stations. Besides, the environmental benefits of PV systems were analyzed, and their amount of energy saving and emission reduction was calculated. This study can solve the issue of the low power supply guarantee rate of field observation stations, provide a design basis and beneficial reference for the construction of environment-friendly field laboratory stations, and realize green energy saving and the sustainable use of energy while protecting the ecosystem from being destroyed.

Laccase (LAC) is the key enzyme responsible for lignin biosynthesis. Here, 57 PgLACs from pomegranate were identified and distributed on eight chromosomes and one unplaced scaffold. They were divided into six groups containing three typical Cu-oxidase domains. Totally, 51 cis-acting elements in the promoter region of PgLACs are involved in response to ABA, GA, light, stress, etc., indicating diverse functions of PgLACs. The expression profiles of 13 PgLACs during the seed development stage showed that most PgLACs expressed at a higher level earlier than at the later seed development stage in two pomegranate cultivars except PgLAC4. Also, PgLAC1/6/7/16 expressed at a significantly higher level in soft-seed ‘Tunisia’; on the contrary, PgLAC37 and PgLAC50 with a significantly higher expression in hard-seed ‘Taishanhong’. Combined with their distinguishing cis-acting elements, it was concluded that PgLAC1/6/7 may respond to GA via TATC-box and GARE-motif, and PgLAC16 repressed the promotor activity of embryo mid-maturation genes via RY-element so as to contribute to softer seed formation, whereas PgLAC37/50 may participate in seed formation and accelerate seed maturity via ABRE and G-box elements. Collectively, the dramatic gene expressions of PgLAC1/6/7/16/37/50 will provide valuable information to explore the formation of soft- and hard-seed in pomegranate.

This paper used poly (aryl ether ketone) (PAEK) resin with a low melting temperature to prepare laminate via the compression-molding process for continuous-carbon-fiber-reinforced composites (CCF-PAEK). Then, poly (ether ether ketone) (PEEK), or a short-carbon-fiber-reinforced poly (ether ether ketone) (SCF-PEEK) with a high melting temperature, was injected to prepare the overmolding composites. The shear strength of short beams was used to characterize the interface bonding strength of composites. The results showed that the interface properties of the composite were affected by the interface temperature, which was adjusted by mold temperature. PAEK and PEEK formed a better interfacial bonding at higher interface temperatures. The shear strength of the SCF-PEEK/CCF-PAEK short beam was 77 MPa when the mold temperature was 220 °C and 85 MPa when the mold temperature was raised to 260 °C. The melting temperature did not significantly affect the shear strength of SCF-PEEK/CCF-PAEK short beams. For the melting temperature increasing from 380 °C to 420 °C, the shear strength of the SCF-PEEK/CCF-PAEK short beam ranged from 83 MPa to 87 MPa. The microstructure and failure morphology of the composite was observed using an optical microscope. A molecular dynamics model was established to simulate the adhesion of PAEK and PEEK at different mold temperatures. The interfacial bonding energy and diffusion coefficient agreed with the experimental results.

Cold stress limits plant growth, development and yields, and the C-repeat binding factors (CBFs) function in the cold resistance in plants. However, how pomegranate CBF transcription factors respond to cold signal remains unclear. Considering the significantly up-regulated expression of PgCBF3 and PgCBF7 in cold-tolerant Punica granatum ‘Yudazi’ in comparison with cold-sensitive ‘Tunisia’ under 4 °C, the present study focused on the two CBF genes. PgCBF3 was localized in the nucleus, while PgCBF7 was localized in the cell membrane, cytoplasm, and nucleus, both owning transcriptional activation activity in yeast. Yeast one-hybrid and dual-luciferase reporter assay further confirmed that PgICE1 could specifically bind to and significantly enhance the activation activity of the promoters of PgCBF3 and PgCBF7. Compared with the wild-type plants, the PgCBF3 and PgCBF7 transgenic Arabidopsis thaliana lines had the higher survival rate after cold treatment; exhibited increased the contents of soluble sugar and proline, while lower electrolyte leakage, malondialdehyde content, and reactive oxygen species production, accompanying with elevated enzyme activity of catalase, peroxidase, and superoxide dismutase; and upregulated the expression of AtCOR15A, AtCOR47, AtRD29A, and AtKIN1. Collectively, PgCBFs were positively regulated by the upstream PgICE1 and mediated the downstream COR genes expression, thereby enhancing freezing tolerance.

The ablation mechanism and performance of carbon fiber (CF)-reinforced poly aryl ether ketone (PAEK) thermoplastic composites were studied in this paper. The results show that the ablation damaged area is controlled by the irradiation energy, while the mass loss rate is controlled by the irradiation power density. In the ablation center, the PAEK resin and CFs underwent decomposition and sublimation in an anaerobic environment. In the transition zone, the resin experienced decomposition and remelting in an aerobic environment, and massive char leaves were present in the cross section. In the heat-affected zone, only remelting of the resin was observed. The fusion and decomposition of the resin caused delamination and pores in the composites. Moreover, oxygen appeared crucial to the ablation morphology of CFs. In an aerobic environment, a regular cross section formed, while in an anaerobic environment, a cortex–core structure formed. The cortex–core structure of CF inside the ablation pit was caused by the inhomogeneity of fibers along the radial direction and the residual carbon layer generated by resin decomposition in an anoxic environment. The description of the ablation mechanism presented in this study broadens our understanding of damage evolution in thermoplastic composites subjected to high-energy CW laser irradiation.

In order to obtain highly optical transparency polyimides, two novel aromatic diamine monomers containing pyridine and kinky structures, 1,1-bis[4-(5-amino-2-pyridinoxy)phenyl]diphenylmethane (BAPDBP) and 1,1-bis[4-(5-amino-2-pyridinoxy)phenyl]-1-phenylethane (BAPDAP), were designed and synthesized. Polyimides based on BAPDBP, BAPDAP, 2,2-bis[4-(5-amino-2-pyridinoxy)phenyl]propane (BAPDP) with various commercial dianhydrides were prepared for comparison and structure-property relationships study. The structures of the polyimides were characterized by Fourier transform infrared (FT-IR) spectrometer, wide-angle X-ray diffractograms (XRD) and elemental analysis. Film properties including solubility, optical transparency, water uptake, thermal and mechanical properties were also evaluated. The introduction of pyridine and kinky structure into the backbones that polyimides presented good optical properties with 91–97% transparent at 500 nm and a low cut-off wavelength at 353–398 nm. Moreover, phenyl pendant groups of the polyimides showed high glass transition temperatures (Tg) in the range of 257–281 °C. These results suggest that the incorporating pyridine, kinky and bulky substituents to polymer backbone can improve the optical transparency effectively without sacrificing the thermal properties.

Fluorocontaining polymers bearing special properties are unique and important materials in modern society. In this work, we focused on the phase behavior and phase diagram of poly(styrene-block-perfluorooctylethyl acrylate) with a volume fraction varying from 0.2 to 0.8. Small-angle X-ray scattering and transmission electron microscopy showed the phase formation in the sequence of hexagonally packed cylinders (HEX) to lamellar layers (LAM) to inverse hexagonally packed cylinders (iHEX) in this series of block polymers. Wide-angle X-ray diffraction experiments proved that the fluorodomains of the LAM phases and the matrix of iHEX phases contained layered structures formed by the crystallization of fluorosegments. During heating, the self-assembled lattice remained intact even after the melting of fluorodomain, with barely changed lattice parameters. Such hierarchical structural formation was understood by chain conformation and domain interaction, which may provide new insight into the molecular design of advanced materials.

To achieve polyimide-metal complexes with enhanced properties, 5-amine-2-(5-aminopyridin-2-yl)-1-methyl-benzimidazole (PyMePABZ) that contains stiff 2-(2′-pyridyl)benzimidazole (PyBI) was synthesized and exploited to construct the Cu(ΙΙ)-crosslinked polyimides (Cu-PIs). These Cu-PIs exhibited higher dielectric, thermal, and mechanical properties with an increase in Cu2+ content. Among them, their dielectric constants (εrS) were up to 43% superior to that of the neat PI, glass transition temperatures (Tgs) were all over 400 °C, and 5% weight loss temperature (T5%) maintained beyond 500 °C. These data indicate that the metal coordination crosslinking provided a useful guide to develop high performance PIs which possess potential application as useful high temperature capacitors.

Background: In colorectal cancer (CRC), tumor deposits (TD) have been used to guide the N staging only in node-negative patients. It remains unknown about the prognostic value of TD in combination with positive lymph node ratio (LNR) in stage III CRC. Patients and methods: The authors analyzed data from 31 139 eligible patients diagnosed with stage III CRC, including 30 230 from the Surveillance, Epidemiology, and End Results (SEER) database as a training set and 909 from two Chinese hospitals as a validation set. The associations of TD and LNR with cancer-specific survival (CSS) and overall survival (OS) were evaluated using the Kaplan-Meier method and Cox regression models. Results: Both TD-positive and high LNR (value =0.4) were associated with worse CSS in the training [multivariable hazard ratio (HR), 1.50; 95% CI: 1.43-1.58 and HR, 1.74; 95% CI: 1.62-1.86, respectively] and validation sets (HR, 1.90; 95% CI: 1.41-2.54 and HR, 2.01; 95% CI: 1.29-3.15, respectively). Compared to patients with TD-negative and low LNR (value <0.4), those with TDpositive and high LNR had a 4.09-fold risk of CRC-specific death in the training set (HR, 4.09; 95% CI: 3.54-4.72) and 4.60-fold risk in the validation set (HR, 4.60; 95% CI: 2.88-7.35). Patients with TD-positive/H-LNR CRC on the right side had the worst prognosis (P <0.001). The combined variable of TD and LNR contributed the most to CSS prediction in the training (24.26%) and validation (32.31%) sets. A nomogram including TD and LNR showed satisfactory discriminative ability, and calibration curves indicated favorable consistency in both the training and validation sets. Conclusions: TD and LNR represent independent prognostic predictors for stage III CRC. A combination of TD and LNR could be used to identify those at high-risk of CRC deaths. [ABSTRACT FROM AUTHOR]