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Commercial polypropylene microfiltration membranes (PPMM) and biaxial oriented polypropylene (BOPP) films were ozonated in aqueous and gaseous media, respectively, followed by graft polymerization of acryl amide (AAm), hydroxyethyl methacrylate (HEMA), and polyethylene glycol (PEG) to improve their surface hydrophilicity. The efficiency of ozonation conducted in the gaseous and aqueous phases was compared, the gaseous phase ozonation was found slightly more effective in generating peroxide groups, while the aqueous phase ozonation was found more effective in grafting polymerization. Scavengers were added to the aqueous phase ozonation, results indicated that both the radical groups and the molecule ozone contributed to the peroxide generation. The free radical groups contributed maximum 25% and 32% for ozonation of PPMM and BOPP, respectively, and the molecule ozone contributed the percentage remaining. Results also showed that the concentration of peroxides generated on the surfaces of PPMM or BOPP increased with the applied ozone dose and ozonation time in both phases. Copper sulfate hydrate (CuSO4·5H2O) and ferric chloride hydrate (FeCl3·6H2O) were added in the aqueous phase ozonation as homogenous catalysts, results showed that the peroxide generation rate of PPMM and BOPP was improved comparing to that of ozonation without catalyst. The peroxide generation of PPMM showed 17% increase by adding copper catalyst, and 16% increase in peroxide generation was observed in ferric catalyzed ozonation of BOPP. The mechanism of the aqueous phase ozonation was investigated, along with that of catalytic ozonation. An enhanced radical process was found for catalytic ozonation in this study. The hydrophilicity of PPMM and BOPP was improved by graft polymerization of AAm, HEMA and PEG initiated by the peroxides. The aqueous phase ozonation was found more effective in grafting. A washing test was conducted using distilled water blending with 10% isopropyl alcohol. When the ozonated membranes and films were washed and compared to the non-washed ones, it was found that the gaseous phase ozonated PPMM or BOPP lost more peroxides than their aqueous phase counterpart after washing. The washing tests showed that the aqueous phase ozonation could induce a better graft polymerization, because part of the tested peroxides from the gaseous ozonation was washed away in the cleaning and grafting process. The improved hydrophilicity of PPMM was indicated by the contact angle reduction from 129° to 91° for AAm grafting; from 126° to 74° for HEMA grafting; and from 126° to 88° for PEG grafting; Fourier Transform Infrared (FTIR) measurements showed additional peaks of functional groups, such as amine (N-H) and amide (–N-C=O) functional groups from the grafted AAm (CH2=CH-CO-NH2); and the Scanning Electron Microscope (SEM) images confirmed amorphicity changes of the graft polymerization. X-ray Diffraction (XRD) diffractogram revealed the crystallinity changes of ozonated and grafted PPMM. Bovine serum albumin (BSA) was used to test the filtration performance of virgin and grafted membranes, the filtration tests demonstrated the improvement in anti-fouling effect of the modified PPMM; and the SEM images of the fouled and washed membranes revealed the pore blockage and recovering on the surface. The hydrophilicity of the grafted BOPP was also improved, indicated by the contact angle reduction of AAm grafted film from 80° to 56°. The FTIR showed additional peaks of N-H and –N-C=O functional groups of grafted AAm. SEM images indicated amorphicity changes of the graft polymerization. The film modified by the aqueous phase ozonation showed its advantages of better graft polymerization, hydrophilicity, and protein adsorption. The results of this study positively impacted the industrial using of PPMM to elongate its duration time of filtration, and improved the applications of BOPP in biomedical areas

Aircraft basic performance is the foundation of the research on aircraft, which is characterized by many parameters. According to the example of the shortest rising time spent on flying from an altitude to another arbitrary one, and the example of matching control of joystick and throttle lever, it is demonstrated that the visualization in scientific computing method is useful for promoting engineering research.

Low altitude microburst wind shear would do harm to aircrafts’ takeoff and landing. In order to analyze flight safety and advise better escape strategies, a mathematical model was built with high fidelity by a vortex ring based microburst model and a flight dynamics model with wind effects. A human pilot model which can describe characteristics of pilots such as skills, experiences, emotion, etc was embedded into the dynamics model. Since the key parameters of the microburst wind shear model and pilot model were set to be stochastic, the Monte Carlo method was adopted to obtain a numerical approximation of the probability density function of the minimum altitude and the F-factors for flight safety analysis.

Pilot should control the aircraft manually when encountering low altitude wind shear during takeoff and landing. For wind shear escape and flight safety research, an effective human pilot model together with wind shear and flight dynamics model should be built with high fidelity. A skill-based human pilot model was built which can describe pilots’ characteristics such as experiences, skills, emotions, reaction abilities, etc. A fuzzy controller was designed for lateral and longitudinal escape control in pilot model. Since single pilot could not represent a group of pilots’ control behavior, some of the model parameters were set to be stochastic, then the Monte Carlo method was adopted to obtain a numerical approximation of safety analysis results. With the probabilistic pilot model, escape strategies and safety analysis can be studied by simulation with high fidelity.

In order to study the semi-active control of landing gear shimmy, expressions of MR damper equivalent damping coefficient with voltage and amplitude was set up firstly. And then, the mathematical model for semi-active control of landing gear shimmy was constructed and maximum energy dissipation approach based on MR was proposed to suppress shimmy. Finally, the critical shimmy velocity varying with the vertical force during taxiing was investigated in different caster lengths. The simulation results show that the performance of MR to suppress shimmy is greatly superior to hydraulic shimmy damper during taxiing, and MR not only suppresses shimmy completely but also exhibits good robustness about some system parameters.

In this paper, we introduce a classification approach to identify definitions of all terms from a aviation professional corpus. The corpora of aviation domain are firstly segmented by LTP platform from HIT. Then four feature selection methods and two classifiers are applied to extract definitions. First of all, we summarize the correct proportion of feature subset used in classification of term definitions, and secondly argue that the naive bayes classifier combined with CHI or ODDS for feature selection achieve the best score in the F1-measure and F2-measure. In the end, we recognize that the use of SVM classifier with linear kernel could achieve very high precision, but the worst recall.

To evaluate the clinical efficacy and safety of acute hypervolemic hemodilution (AHH) in posterior spinal fusion surgery in children.36 children with scoliosis ASA I approximately II, receive of posterior spinal fusion, were randomly divided into 2 equal groups: AHH group, transfused with hydroxyethyl starch 130/0.4 and sodium chloride (Voluven) 12 ml/kg at the speed of 0.3 approximately 0.4 mlxkg(-1)xmin(-1) (for 30 approximately 40 min) through internal jugular vein before operation so as to keep the hemodilution (Hb) status during operation, and control (CNT) group. During operation when the Hb was80 g/L or the hematocrit was25% blood transfusion was conducted to maintain the Hct25%.There was no significant difference in intra-operative blood loss between these 2 groups. The Hb one day after operation of the AHH group was (89 +/- 12) g/L, significantly lower than that immediately after operation [(98 +/- 10) g/L, P0.05]. The Hb one day after operation of the CNT group was (92 +/- 22) g/L, significantly lower than that immediately after operation [(94 +/- 13) g/L, P0.05]. However, there were not significant differences in the Hb values between the AHH and CNT groups (all P0.05). Both groups received intra-operative transfusion during operation. The amount of transfused red blood cells and fresh frozen plasma of the AHH group were (18 +/- 4) ml/kg and (3.5 +/- 1.1) ml/kg respectively, both significantly lower than those of the CNT group [(28 +/- 11) and (5.8 +/- 1.8) ml/kg respectively, both P0.05].Able to reduce intra-operative blood transfusion and medical expense, AHH can be used safely and effectively in posterior spine fusion in children.

Background The target-controlled infusion-III (SLOG/TCI-III) system was derived from a model set up by the local pediatric population for target control infusion of propofol. Methods The current study aimed at evaluating the difference between target concentrations of propofol and performance, which was measured using the SLOG/TCI-III system in children. Thirty children fulfilling the I-II criteria according to American Society of Anesthesiology were enrolled in the study. The target plasma concentration of propofol was fed into the SLOG/TCI-III system and compared with the measured concentrations of propofol. Blood samples were collected and analyzed by high performance liquid chromatography with fluorescence detector. The performance error (PE) was determined for each measured blood propofol concentration. The performances of the TCI-III system were determined by the median performance error (MDPE), the median absolute performance error (MDAPE), and Wobble (the median absolute deviation of each PE from the MDPE), respectively. Results Concentration against target concentration showed good linear correlation: concentration = 1.3428 target concentration - 0.2633 (r = 0.8667). The MDPE and MDAPE of the pediatric system were 10 and 22%, respectively, and the median value for Wobble was 24%. MDPE and MDAPE were less than 15 and 30%, respectively. Conclusions The performance of TCI-III system seems to be in the accepted limits for clinical practice in children.

Semi-active landing gear can provide good performance of both landing impact and taxi situation, and has the ability for adapting to various ground conditions and operational conditions. A kind of Nonlinear Model Predictive Control algorithm (NMPC) for semi-active landing gears is developed in this paper. The NMPC algorithm uses Genetic Algorithm (GA) as the optimization technique and chooses damping performance of landing gear at touch down to be the optimization object. The valve's rate and magnitude limitations are also considered in the controller's design. A simulation model is built for the semi-active landing gear's damping process at touchdown. Drop tests are carried out on an experimental passive landing gear systerm to validate the parameters of the simulation model. The result of numerical simulation shows that the isolation of impact load at touchdown can be significantly improved compared to other control algorithms. The strongly nonlinear dynamics of semi-active landing gear coupled with control valve's rate and magnitude limitations are handled well with the proposed controller.