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The equilibrium adsorption characteristics of nitrogen adsorbents were tested and a suitable nitrogen adsorbent was selected for producing oxygen by rapid vacuum pressure swing adsorption. Due to low oxygen concentration in the product obtained by traditional rapid pressure swing adsorption,an improved pressurization step with raffinate was developed and experimentally studied in a rapid vacuum pressure swing adsorption system for producing oxygen. The results show that combined pressurization with raffinate and feed gas can effectively improve the oxygen concentration in the product during the rapid vacuum pressure swing adsorption process. The pressure and oxygen concentration of raffinate for pressurizing are key parameters to influence the oxygen concentration in the product,and a higher concentration oxygen product can be obtained by taking an appropriate pressure and a higher oxygen concentration of raffinate. The 90% oxygen can be generated by combined pressurization with raffinate and feed gas during the rapid vacuum pressure swing adsorption process with an adsorption pressure of 240 k Pa and a desorption pressure of 60 k Pa,and the adsorbent productivity is 325. 08 L·h-1·kg-1.

A 2D axisymmetric mathematical model was developed for an O2 generator and the protective performance of the O2 generator was simulated. The model's rationality was verified by experiments under typical operational conditions. Then, the influ-ences of labor intensity, inlet CO2 volume faction, equivalent diameter of oxygen-generating particles, and pipe diameter at the entrance on the protective performance of the O2 generator were studied by the model. The simulated results show that both labor inten-sity and inlet CO2 volume faction have significant effect on the protective performance of the O2 generator. A higher labor intensity and a higher inlet CO2 volume faction share the same trend, which means a much shorter protective time and a much higher outlet peak temperature. The protective time decreases with increasing equivalent diameter of oxygen-generating particles, exhibiting an approxi-mately negative liner relationship. The protective time for 12 mm particles is 32.15 min shorter than that for 6 mm particles. However, larger particles will lead to a lower outlet peak temperature. Different from the front three factors, pipe diameter at the entrance has limited effect on both the protective time and outlet temperature.

Objective: To observe the effect of intranasal acupuncture on allergic rhinitis (AR), and expression of substance P (SP), vasoactive intestinal peptide (VIP) and neuropeptide Y (NPY) proteins in the nasal mucosa and contents of serum immunoglobulin E (IgE), interleukin 4 (IL-4) and interferon-γ (IFN-γ) in AR rabbits, so as to explore its mechanisms underlying improvement of AR., Methods: New Zealand rabbits were randomly divided into normal control, AR model, non-acupuoint acupuncture (NAA) and intranasal acupuncture (INA) groups, with 8 rabbits in each group. The AR model was established by intra-peritoneal injection of egg protein and nasal mucosal stimulation. In the INA group, bilateral "Neiyingxiang" (EX-HN9) within the nasal cavity (the anterior attachment area of the inferior turbinate, about 1 cm away from the nasal limen) were acupunctured by mani-pulating the filiform needles for a while with uniform reinforcing and reducing methods, followed by keeping the needles for 20 min. In the NAA group, shallow acupuncture was applied to the skin of the outer margin of the cheeks, followed by keeping the needle for 20 min. The acupuncture treatment was conducted once every other day for 7 days. The symptoms of sneezing frequency, nasal secretion amount and nasal itching were scored. The expression levels of SP, VIP and NPY in the nasal mucosa tissue were detected by immunohistochemistry, and the serum IgE, IL-4, and IFN-γ contents were detected by ELISA., Results: After modelling, the symptom score, expression of SP and VIP, and serum IgE and IL-4 contents were significantly higher (P<0.01,P<0.05), NPY expression and serum IFN-γ content significantly lower (P<0.05, P<0.01) in the model group than in the normal control group. Following the intervention, the symptom scores, expressions of SP and VIP, and serum IgE and IL-4 contents were remarkably decreased (P<0.05, P<0.01), while the NPY expression and serum IFN-γ content were significantly up-regulated (P<0.05, P<0.01) in the INA group than in the model group. The effects of INA group were significantly superior to those of NAA group in reducing symptom score, SP and VIP expression, and serum IgE and IL-4 contents and up-regulating NPY expression and IFN-γcontent (P<0.05, P<0.01). There were a positive correlation between the expressions of SP and VIP and contents of serum IgE and IL-4 (P<0.05), and a negative correlation between the expressions of SP and VIP and IFN-γ content (P<0.05)., Conclusion: INA treatment can relieve symptoms of AR in AR rabbits, which may be associated with its effects in regulating the expression of SP, VIP and NPY of the nasal mucosa, and contents of serum IgE, IL-4 and IFN-γ to improve neurogenic inflammation.