苯二酚在PTh/NTiO2/GCE上的电化学行为的研究

该文利用循环伏安法(CV)和线性扫描溶出伏安法(LSSV)研究了对苯二酚(HQ)和间苯二酚(RS)在聚噻吩/纳米二氧化钛修饰玻碳电极(PTh/NTiO2/GCE)上的电化学行为。该修饰电极作为两种苯二酚传感器表现出极好的灵敏度和选择性。在0.2mol/L柠檬酸-磷酸氢二钠缓冲溶液(pH 4.6),RS和HQ的氧化峰电位相距508 mV,且在PTh/NTiO2/GCE上的峰比在裸GCE上的高出6.5倍。在最佳条件下,PTh/NTiO2/GCE对HQ和RS在1.0×10-7～8.0×10-6范围内都有较好的线性关系,混合物中的检出限(S/N=3)分别为3.3×10-8 mol/L和3.7×10-8 mol/L。通过计算得出了一些动力学参数如电子转移数(n),质子转移数(m)。该法被用来同时测定废水中的RS和HQ结果满意。     

基于古诺模型的斯密悖论探究——兼评心理主义与反心理主义

＂斯密悖论＂指斯密在《国富论》中以利己心为核心的经济人和《道德情操论》中以同情心为核心的道德人之间的矛盾。一个半世纪以来,国内外学界围绕着这一＂悖论＂的研究持续不断。借助古诺模型的方法对＂斯密悖论＂中的经济人与道德人进行博弈分析,试图提出利己与利他的有机统一体——经济道德人。     

滨海新区现代物流基础岗位人才需求与教育衔接的研究

近年来,滨海新区经济一直保持稳步上涨趋势。通过调查研究发现企业人才需求,与现在高职教育不能实现完全对接。通过分析企业对人才的能力要求,找出目前高职教学计划、教学方法的不当之处,建议构建"一体两翼"式的课程体系、推进"2+1"教学模式等措施,强化高职生能力素质,进而培养出适应滨海新区经济发展需要的实用型人才。     

A new principle and device for large aircraft components gaining accurate support by ball joint

How to obtain an accurate support for large components by ball joint is a key process in aircraft digital assembly. A novel principle and device is developed to solve the problem. Firstly, the working principle of the device is introduced. When three or four displacement sensors installed in the localizer are touched by the ball-head, the spatial relation is calculated between the large aircraft component’s ball-head and the localizer’s ball-socket. The localizer is driven to achieve a new position by compensation. Relatively, a support revising algorithm is proposed. The localizer’s ball-socket approaches the ball-head based on the displacement sensors. According to the points selected from its spherical surface, the coordinates of ball-head spherical center are computed by geometry. Finally, as a typical application, the device is used to conduct a test-fuselage’s ball-head into a localizer’s ball-socket. Positional deviations of the spherical centers between the ball-head and the ball-socket in the x, y, and z directions are all controlled within ±0.05 mm under various working conditions. The results of the experiments show that the device has the characteristics of high precision, excellent stability, strong operability, and great potential to be applied widely in the modern aircraft industry.     

Comparison of different techniques for time-frequency analysis of internal combustion engine vibration signals

In this study, we report an analysis of cylinder head vibration signals at a steady engine speed using short-time Fourier transform (STFT). Three popular time-frequency analysis techniques, i.e., STFT, analytic wavelet transform (AWT) and S transform (ST), have been examined. AWT and ST are often applied in engine signal analyses. In particular, an AWT expression in terms of the quality factor Q and an analytical relationship between ST and AWT have been derived. The time-frequency resolution of a Gaussian function windowed STFT was studied via numerical simulation. Based on the simulation, the empirical limits for the lowest distinguishable frequency as well as the time and frequency resolutions were determined. These can provide insights for window width selection, spectrogram interpretation and artifact identification. Gaussian function windowed STFTs were applied to some cylinder head vibration signals. The spectrograms of the same signals from ST and AWT were also determined for comparison. The results indicate that the uniform resolution feature of STFT is not necessarily a disadvantage for time-frequency analysis of vibration signals when the engine is in stationary state because it can more accurately localize the frequency components excited by transient excitations without much loss of time resolution.     

Dynamic responses of cable-stayed bridges to vehicular loading including the effects of the local vibration of cables

Stay cables, the primary load carrying components of cable-stayed bridges (CSBs), are characterised by high flexibility which increases with the span of the bridge. This makes stay cables vulnerable to local vibrations which may have significant effects on the dynamic responses of long-span CSBs. Hence, it is essential to account for these effects in the assessment of the dynamics CSBs. In this paper, the dynamic responses of CSBs under vehicular loads are studied using the finite element method (FEM), while the local vibration of stay cables is analyzed using the substructure method. A case study of a cable-stayed steel bridge with a center span of 448 m demonstrates that stay cables undergo large displacements in the primary mode of the whole bridge although, in general, a cable’s local vibrations are not obvious. The road surface roughness has significant effects on the interaction force between the deck and vehicle but little effect on the global response of the bridge. Load impact factors of the main girder and tower are small, and the impact factors of the tension of cables are larger than those of the displacements of girders and towers.     

高职教育实践教学体系要素构建研究

文章探讨了高职教育实践教学体系的特征,构建高职实践教学体系的原则,阐述了高职实践教学体系的构成要素,构建实践教学体系应注意的几个环节。     

中韩两国教师在职教育政策的比较

教师是教育事业发展的第一资源。在一定意义上说,教师的质量就是教育的质量,教育的差距归根结底是教师的差距。这已经成为世界各国的共识。而教师队伍整体素质的提高很大程度上取决于那些己经成为教师或是意愿成为教师的人的教育水平的提高。新中国成立之后,我国在不断摸索中制定教师在职教育政策,旨在提高教师素质和专业发展水平,从而提升国家的教育水平。光复之后,韩国国内百废待兴,国家也开始重视对教师的教育,并制定了一系列政策促进、鼓励教师参加职后培训。本文将按照历史沿革,对1949年以后,中韩两国中小学教师在职教育政策制定的内容和实际效果、影响等展开比较,分析不同国家政策制定的价值取向和特点,并在比较中思考和借鉴。     

Exploring the cosmopolitanism in China: examining mosheng ren (“the stranger”) communication through Momo

This paper discusses a phenomenon that has become popular in mainland China in recent years, “mosheng ren communication,” focusing specifically on an application known as Momo, a social discovery and dating platform that is widely used in China. It first outlines the context of post-Mao China, which has produced urbanism, individualization, and a sexual revolution. Thereafter, it turns to the theories of the stranger and cosmopolitanism, which are used to analyze mosheng ren communication. This paper adopts cultural discourse analysis as the analytical procedure to present the findings of online and offline interviews conducted in both Beijing and Shanghai to examine how Momo users in urban metropolises make use of this app in order to analyze the cultural radiants in their communication practices. Based on the data obtained, this paper analyzes mosheng ren communication in the Chinese context and describes how Momo is designed to facilitate it. Momo users can enter into sexual relations based on the use of authentic photos on their profiles; alternatively, they can communicate anonymously. They are also “in-between” traditional Chinese values and new values. Momo users contribute a Chinese form of cosmopolitanism through cultivation of insensitivity to mosheng ren, while their engagement in mosheng ren communication implies that the members of are more open to others.     

土荆芥浸提液对几种种子萌发的化感作用

采用室内生物测定法,以小麦,油菜,上海青等作物为受体,研究了土荆芥的化感作用.结果表明:①土荆芥叶的浸提液对3种作物种子萌发均具有抑制作用,且这种抑制作用随着浸提液浓度的增加而增强;②浓度为0.01g/mL和0.02g/mL的茎的浸提液对上海青、油菜的幼苗生长有促进作用;③相同浓度的土荆芥叶浸提液对供试种子萌发的的抑制作用强于茎浸提液.