Papers by Keyword: N₂

Abstract: The gate insulator process for SiC-MOSFET was examined and high-quality interface was realized by employing the pre-annealing process before high-temperature N₂ annealing. The pre-annealing evidently activated the interface to introduce nitrogen, and then field-effect mobility exceeded 50 cm²/Vs. The fabricated sample also demonstrated superior bias temperature instability (BTI) and excellent breakdown electric field of 11.7 MV/cm.

Abstract: Titanosilicate ETS-4 with the Sr and Ni cations modification were prepared by hydrotherrmal method using titanium trichloride and tetraethoxysilane as raw materials. The properties and morphology of the materials were characterized by XRD, SEM techniques, Sr and Ni introduced to the molecular sieve affected the frame contraction when they were heated, and did little effect on the crystallization and morphology. N₂ and CH₄ isotherms of each sample were measured at room temperature. The Sr and Ni doping could improve the N₂ and CH₄ adsorption capacities of ETS-4. The capacities of the two gases increased in the pressurization process for ETS-4-Sr and ETS-4-Ni, with the pressure increasing, no significant change in capacities of N₂ and CH₄ was observed over the ETS-4 sample. Compared to ETS-4 molecular sieves, the capacity for N₂ of ETS-4-Sr and ETS-4-Ni at the pressure of 1200 mmHg increased 4.2 and 3.9 times, respectively. At last, the results indicated that the cations doping (Sr²⁺ and Ni²⁺) can improve the adsorption performance of ETS-4 greatly.

Abstract: Based on the systematic analysis of the data of 46 coalbed gas samples, this paper discusses the coal metamorphism’s influence on coaled N2 concentration in Mining Area . The results show that:Yanshanian magma’s "baking" is the main reason for the high N2 concentration; The coal metamorphic degree enhanced, ratios of N2/CH4 present the changing rule of "increase-decrease-increase"; In coking coal stage, the liberation rate of N2 by thermal ammonization is faster than the liberation rate of CH4, so ratios of N2/CH4 increase; In meager coal stage, NH3 generated by thermal ammonization participates in the formation of ammonium illite in the form of NH4+, thus the liberation rate of N2 decreases relatively, so ratios of N2/CH4 decrease; In the lean coal stage, organic nitrogen liberates N2 by thermal cracking effect, N2 concentration increases relatively again, so ratios of N2/CH4 increase.

Abstract: Electrospinning combined with nonsolvent-induced phase separation is a simple and novel method to produce porous nanofibers. In the study, Poly (vinylpyrrolidone) (PVP) nanofibers were fabricated using an electrospinning approach complemented by compressed nitrogen (N). N2 was used as the nonsolvent of choice. Besides, the tun₂ning of N₂ pressure and temperature can impact the nanofibers’ morphologies by altering phase behavior and mass transfer. Also, the other parameters affecting electrospinning of polymer solution were discussed. The results were demonstrated by extending the technique to PVP/dichloromethane (DCM) and PVP/ethanol (EtOH) systems. And the binary phase equilibrium of solvents (dichloromethane or ethanol) and N simulated by ASPEN PLUS 2006 demonstrates that N is not a ₂good choice for producing hollow or po₂rous polymer nanofibers.

Abstract: In this paper, SAF2507 duplex stainless steel (DSS) was welded by GTAW with ER2594 as filler wire, and Ar + N₂ as shielding gas. The results show that, with increasing the content of N₂ in the shielding gas, the amount of austenite in weld metal increase, the micro-hardness drops and impact energy increases; the use of Ar +2 ~ 3% N₂ welding parameters, the microstructure and mechanical properties of welded joints are the best, the austenitic rates and impact energy of weld metals are 51%~53% and 75~88 J, respectively, and the welding process is easy to control; when the content of N₂ reach 5%, the impact energy of weld metal decreases obviously and the welding arc is unstable.