初二男生30秒30次蹲起机能测试、研究和评价

我们中学体育的一个重要任务是增强学生体质,而心肺功能是衡量体质强弱的一个重要方面。利用动态机能试验是测量心血管系统机能状况的典型而有效的手段,而近年来有关对男生心肺功能水平的评价,所选用的指标多只是肺活量等,尚未运用动态试验指标,更未有试验的评价标准。测量负荷前后的脉率变化,并通过统计分析,反映男生的心肺功能状况,有广泛应用于中学生进行群体测量的优点,具有很高的实用价值。为此本文通过初二男生心肺功能的测试,经过统计分析相应地制定心功等级评价标准,为中学体育在评价男生的心肺功能方面提供客观依据。同时,教师也可根据评价标准,有目的地组织学生进行身体锻炼,从而提高体育教学工作的针对性与实效性。

产品机能转化需求层级的设计方法研究

目的用一种基于产品机能分析及Kano模型的设计方法来优化产品设计与开发流程。方法通过机能分析,得到产品各机能及次机能,并将次机能转换成为用户需求,通过Kano模型对用户需求进行分类,得到不同层级的用户需求后转化成不同层级的设计特征,以无线路由器的设计为案例,探讨本方法在产品设计流程中的有效性。结论该方法能够直观地体现用户对产品不同层级的需求,有利于优化产品设计流程,制定机能设计规范,明确设计目标,提高用户满意度。

Malware Detection in Smartphones Using Static Detection and Evaluation Model Based on Analytic Hierarchy Process

Mobile malware is rapidly increasing and its detection has become a critical issue. In this study, we summarize the common characteristics of this inalicious software on Android platform. We design a detection engine consisting of six parts： decompile, grammar parsing, control flow and data flow analysis, safety analysis, and comprehensive evaluation. In the comprehensive evaluation, we obtain a weight vector of 29 evaluation indexes using the analytic hierarchy process. During this process, the detection engine exports a list of suspicious API. On the basis of this list, the evaluation part of the engine performs a compre- hensive evaluation of the hazard assessment of software sample. Finally, hazard classification is given for the software. The false positive rate of our approach for detecting rnalware samples is 4. 7% and normal samples is 7.6%. The experimental results show that the accuracy rate of our approach is almost similar to the method based on virus signatures. Compared with the method based on virus signatures, our approach performs well in detecting unknown malware. This approach is promising for the application of malware detection.

Secondary aerosol formation and oxidation capacity in photooxidation in the presence of Al_2O_3 seed particles and SO_2

To investigate the sensitivity of secondary aerosol formation and oxidation capacity to NOx in homogeneous and heterogeneous reactions, a series of irradiated toluene/NOx/air and ?-pinene/NOx/air experiments were conducted in smog chambers in the absence or presence of Al2O3 seed particles. Various concentrations of NOx and volatile organic compounds(VOCs) were designed to simulate secondary aerosol formation under different scenarios for NOx. Under "VOC-limited" conditions, the increasing NOx concentration suppressed secondary aerosol formation, while the increasing toluene concentration not only contributed to the increase in secondary aerosol formation, but also led to the elevated oxidation degree for the organic aerosol. Sulfate formation was suppressed with the increasing NOx due to a decreased oxidation capacity of the photooxidation system. Secondary organic aerosol(SOA) formation also decreased with the presence of high concentration of NOx, because organo-peroxy radicals(RO2) react with NOx instead of with peroxy radicals(RO2 or HO2), resulting in the formation of volatile organic products. The increasing concentration of NOx enhanced the formation of sulfate, nitrate and SOA under "NOx-limited" conditions, in which the heterogeneous reactions played an important role. In the presence of Al2O3 seed particles, a synergetic promoting effect of mineral dust and NOx on secondary aerosol formation in heterogeneous reactions was observed in the photooxidation. This synergetic effect strengthened the positive relationship between NOx and secondary aerosol formation under "NOx-limited" conditions but weakened or even overturned the negative relationship between NOx and secondary aerosol formation under "VOC-limited" conditions. Sensitivity of secondary aerosol formation to NOx seemed different in homogeneous and heterogeneous reactions, and should be both taken into account in the sensitivity study. The sensitivity of secondary aerosol formation to NOx was further investigated under "winter-like" and NH3-rich conditions. No obvious difference for the sensitivity of secondary aerosol formation except nitrate to NOx was observed.

Investigation of modification design of the fan stage in axial compressor

The S2 flow path design method of the transonic compressor is used to design the one stage fan in order to replace the original designed blade cascade which has two-stage transonic fan rotors.In the modification design,the camber line is parameterized by a quartic polynomial curve and the thickness distribution of the blade profile is controlled by the double-thrice polynomial.Therefore,the inlet flow has been pre-compressed and the location and intensity of the shock wave at supersonic area have been controlled in order to let the new blade profiles have better aerodynamic performance.The computational results show that the new single stage fan rotor increases the efficiency by two percent at the design condition and the total pressure ratio is slightly higher than that of the original design.At the same time,it also meets the mass flow rate and the geometrical size requirements for the modification design.