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SiC-ZrC composite powders were synthesized by carbothermal reduction method using starch as carbon source, zirconium dioxide as zirconium source, and silica sol as silicon source. The effects of reaction temperature on the phase composition and microstructure of SiC-ZrC composite powders were investigated. The reaction process was thermodynamically analyzed and calculated, and the synthesis mechanism of SiC-ZrC composite powder was analyzed. The synthesized powder samples were characterized and analyzed by X-ray diffraction, scanning electron microscopy, and other testing methods. Results show that the optimum reaction condition for the synthesis of SiC-ZrC composite powders is at 1550 ̊C-1600 ̊C for 1.5 h. High temperature and low pressure are beneficial in conducting the synthesis reaction. The SiC-ZrC composite powders synthesized by calcining at 1550 ̊C and holding for 1.5 h are mainly composed of a certain amount of whiskers, spherical particles, floc particles, and other structures. Moreover, their grain size is small (100-200 nm). The powder samples synthesized at 1600 ̊C produced a larger number of whiskers. The length of the whiskers was mostly 10 μm, the arrangement was complex and irregular, and a diverse microstructure was formed.

SiC-TiC composite powders were synthesised through carbothermal reduction under an argon atmosphere by using silica sol, starch, and TiO₂ as the raw materials. The influences of the starch dosage and holding time on the synthesis of SiC-TiC composite powder are discussed in detail. The samples were characterised using an X-ray diffractometer (XRD), an integrated thermal analyser (TG-DTA), a scanning electron microscope (SEM), and an energy spectrometer (EDS). The results showed that the SiC-TiC composite powders were completely synthesised after holding at 1550 °C for 3 h when the amount of excess starch was 5 wt% and after holding at 1550 °C for 2 h when the amount of excess starch was 10 wt%-20 wt%. The morphological characteristics of the powder samples with 5 wt%-15 wt% excess starch calcined at 1550 °C for 2 h were mainly flake particles, spherical particles, irregularly shaped particles and elongated whiskers. Conversely, no whiskers were found in the powder samples calcined at 1550 °C for 2 h when the amount of excess starch was 20 wt%.

Using aluminum hydroxide (Al(OH)₃) and aluminum nitrate (Al(NO₃)₃.9H₂O) as aluminum sources and highly active glucose (C₆H12O₆) as a carbon source, we synthesized ultrafine AlN powder through carbothermal reduction-nitridation. Then, we explored the effects of aluminum sources, reaction temperature, holding time and other reaction conditions on the phase composition and micromorphology of the synthesized AlN powder. Result showed that AlN powder and different proportions of Al₂O₃-AlN composite powder can be prepared by controlling reaction temperature or holding time. Under the conditions of this experiment, Al(OH)₃ more beneficial as an aluminum source for carbothermal reduction-nitridation than Al(NO₃)₃.9H₂O. The optimum reaction conditions for the synthesis of single-phase AlN powder with Al(OH)₃ as aluminum source were holding time of 3 h and temperature of 1450 °C. The powder sample synthesized under this reaction condition is mainly composed of flaky, short-rod, and irregularly shaped fine particles with sizes ranging from 50 nm to 100 nm.

This paper takes the ultra-low permeability sandstone reservoir of Jingbian oilfield in Ordos Basin as the research object, analyzes the petrological characteristics, diagenesis, physical characteristics and pore structure characteristics of the reservoir, and carries out reservoir sensitivity evaluation by using rock casting thin sections, X-ray diffraction, and sensitive flow experiments. The research results show that the ultra-low permeability Chang 6 sandstone reservoir has weak velocity sensitivity, medium-weak water sensitivity, weak salt sensitivity, weak alkali sensitivity and strong acid sensitivity; the damage mechanism of reservoir sensitivity mainly depends on the composition of clay minerals and pore structure after diagenesis. The clay mineral content from high to low is chlorite, illite, a small amount of illite / smectite layer, and kaolinite, of which the chlorite content is as high as 75 %; the reservoir has poor physical properties, the types of small hole-thin throat and small hole-fine throat. The reservoir is prone to blockage such as bridge plugging. Therefore, ultra-low permeability sandstone reservoirs are prone to different degrees of sensitivity. The reservoir characteristics are consistent with the reservoir sensitivity evaluation results.

In recent years, with the rapid development of the economy, the dangerous chemicals enterprises in Qingyang City have also expanded and developed rapidly. The development of hazardous chemicals enterprises is increasing, the factors of instability are increasing, and the frequency of accidents involving hazardous chemicals is also increasing. While hazardous chemicals companies bring benefits, they also bring a serious threat to human life, health and property security. As a city with more dangerous chemicals companies, Qingyang has many potential safety hazards. In order to cope with many pressures, the Qingyang Municipal Government is vigorously carrying out safety production inspection and emergency mechanism construction in the hazardous chemicals industry. This paper analyzes the problems and deficiencies in the emergency management mechanism of Qingyang City from the aspects of accident prevention and early warning, emergency response, emergency plan preparation and emergency drill, which are mainly reflected in the weak foundation of accident early warning, imperfect laws and regulations, and weak awareness of public participation in emergency management. Finally, through the analysis of the existing problems and deficiencies, the emergency mechanism of Qingyang dangerous chemicals accident is improved.

Brittleness determines the effect of reservoir fracturing and is important for increasing the production of unconventional oil and gas. The reservoir of Yanchang gas field is characterized by low porosity, low permeability and strong heterogeneity, which make it difficult to produce industrial gas flow under natural conditions. Triaxial compression tests in sandstone samples of Shihezi formation in Yanchang gas field show that the main fracturing mode is multiple horizontal splitting, the main cracks are completely fractured, and the brittleness index ranges from 46.1% to 51.4%. After S-wave velocity model in the study area is established, the conversion relation of dynamic and static mechanical parameters could be obtained, that is, Es=0.4142Ed+10.769 (R2=0.8387), and μs=1.1076 μd-0.068 (R2=0.7366), according to which, the dynamic mechanics parameters calculated by well logging can be adjusted, and then the reservoir brittleness could be quantitatively evaluated. Combining with the brittleness index calculated by mineral component method, it can be concluded that the brittleness calculated by well logging is reliable and the brittleness of Shihezi formation in Yanchang gas field is high, which is beneficial for reservoir fracturing.

Rock samples from X-1 and X-2 well of Chang 7 shale in Longdong area in Ordos Basin are studied through triaxial compression test and acoustic wave test in order to obtain accurate data about the mechanical characteristics of the stratum and fracturing parameters.The static Young’s modulus ranges from 2.213 GPa to 4.195 GPa and the static Poisson’s ratio ranges from 0.181 to 0.239 in triaxial compression test. The dynamic Young’s modulus ranges from 2.659 GPa to 5.03 GPa and the dynamic Poisson’s ratio ranges from 0.20 to 0.29 in acoustic wave test. It can be seen that the dynamic Young’s modulus is slightly larger than the static Young’s modulus, and the relation between them is Es=0.8492Ed-0.1349, while the dynamic and static Poisson’s ratios are basically same, that is, μs≈μd.

The thermal stability of the polyethylene (PE) separator is of utmost importance for the safety of lithium-ion batteries. Although the surface coating of PE separator with oxide nanoparticles can improve thermal stability, some serious problems still exist, such as micropore blockage, easy detaching, and introduction of excessive inert substances, which negatively affects the power density, energy density, and safety performance of the battery. In this paper, TiO2 nanorods are used to modify the surface of the PE separator, and multiple analytical techniques (e.g., SEM, DSC, EIS, and LSV) are utilized to investigate the effect of coating amount on the physicochemical properties of the PE separator. The results show that the thermal stability, mechanical properties, and electrochemical properties of the PE separator can be effectively improved via surface coating with TiO2 nanorods, but the degree of improvement is not directly proportional to the coating amount due to the fact that the forces inhibiting micropore deformation (mechanical stretching or thermal contraction) are derived from the interaction of TiO2 nanorods directly "bridging" with the microporous skeleton rather than those indirectly "glued" with the microporous skeleton. Conversely, the introduction of excessive inert coating material could reduce the ionic conductivity, increase the interfacial impedance, and lower the energy density of the battery. The experimental results show that the ceramic separator with a coating amount of ~0.6 mg/cm2 TiO2 nanorods has well-balanced performances: its thermal shrinkage rate is 4.5%, the capacity retention assembled with this separator was 57.1% under 7 C/0.2 C and 82.6% after 100 cycles, respectively. This research may provide a novel approach to overcoming the common disadvantages of current surface-coated separators. [ABSTRACT FROM AUTHOR]