职业院校高水平“双师型”教师队伍建设研究——以“双向流动”机制为背景

“双师型”教师队伍一直以来是职业教育师资队伍的核心。随着“职教20条”“双高计划”的陆续颁布,国家对职业教育的发展提出新的目标和要求,提升职业院校“双师型”教师队伍的整体质量迫在眉睫。为此,项目团队通过多方调研,对我国“双师型”教师队伍的现状进行分析,并重新定义“双师型”教师概念,丰富“双师型”教师内涵。结合校企合作“双向流动”机制,尝试从职业院校师德师风、师资来源、保障机制和培养机制等方面找到高水平“双师型”教师队伍建设的路径。

校企人员“双向流动”的内涵、困境与实践路径

当前,我国校企人员“双向流动”面临诸多现实困境,如流动机制的缺失导致人员流动意愿低迷、企事业人事制度的分离导致低水平流动、先前工作成果的割裂导致流动人员生涯发展的“断层”等。实现校企人员高水平“双向流动”需要教育系统内外部力量通力合作,不断推动顶层制度设计,构建“双向流动”常态运行机制,以用人机制为抓手推动校企人事制度改革,积极探索校企流动人员工作成果互认,逐步破除校企人员低水平流动的障碍。

Osmotic concentration of succinic acid by forward osmosis:Influence of feed solution pH and evaluation of seawater as draw solution

In this study, we investigated the essential role of feed solution pH so as to gain insights into the transport mechanisms of succinic acid concentration by osmotically-driven forward osmosis （FO） process. FO performances including water flux and bidirectional transport of succinate and chloride anions were systematically examined using cellulose triacetate-based FO membrane. Additionally, real seawater was explored as draw solution. Experimental results revealed that the pH-dependent speciation of succinic acid can affect the FO performances. Ionization of succinic acid at higher solution pH enhanced the osmotic pressure of feed solution, thus leading to lower water flux performance. A strong effect was pointed out on the succinate rejection for which nearly 100% rejections were achieved at pH above its pKa2 value. The rejection of succinate increased in the following order of chemical form： C2H4C2O4H2 〈 C2H4C2OH- 〈 C2H4C2O24-. With real seawater as the draw solution, low to moderate water fluxes （〈4 L. m- 2. h- 1 ） were observed. The divalent succinate anion was highly retained in the feed side despite differences in the succinic acid feed concentration at pH of approximately 6.90.

Smart Solar Charging： Bi-Directional AC Charging （V2G） in the Netherlands

It is to be expected that the number of electric vehicles will be growing in the near future. This trend comes together with the development of smaller decentralized generation units, like PV （photo voltaic）. Together with the change on demand side that comes with the global ＂electrification＂, this can lead to serious grid congestion in low voltage grids and massive grid investments in solving this congestion. Smart charging can partly solve this issue, but with using a connected EV （electric vehicle） as a small distribution unit, combined with bi-directional charging or V2G （vehicle-to-grid） technology, these investments can be reduced to a minimum. In Lombok, Utrecht, the Netherlands, an innovative pilot was initiated with smart solar charging stations, shared electric vehicles and AC （alternating current） V2G technology. This unique combination proves that EVs are an opportunity for the grid rather than a threat. A unique partnership with OEM Renault was established to develop an AC V2G vehicle product line and work on open standardized communication between the EV, the charging station and the grid.

对城市“民工荒”与农村劳动力过剩并存现象的探讨——以A庄调查为例

中国2004—2008年出现的"民工荒"使人们对中国农村到底还剩余多少劳动力产生了兴趣。本文通过调查一个具有典型劳动力输出特征的村庄从微观角度回答了该问题。调查发现中国出现了农村劳动力剩余与城市用工紧张并存的矛盾现象。文章提出了一个基于家庭决策的"双向"流动的劳动力转移模型,并用此模型解释了上述现象。文章建议逐步放开户籍制度,鼓励有条件农民工全部转移到城市,给回乡的农民工提供更多培训与资金支持,鼓励他们进行创业。

Effect of Elastic Constitutive Laws on the Deformation of Two-dimensional Red Blood Cell

Deformation of two-dimensional red blood cell in linear shear flow is simulated using the immersed boundary method,in which the cell is modeled as a force source instead of a real body.The effect of three constitutive laws,i.e.Hookean,Neo-Hookean and Skalak elasticity,on the deformation is studied by simulating the cell movement in two linear shear flows.The results show that the effect of the constitutive laws gets more obvious as the shear rate increases.Both the aspect ratio and the inclination of the steady shapes get bigger, and the differences between the periods of the cell tank-treading motion become larger.For the same shear flow, the period with Hookean elasticity is less than the period with Neo-Hookean elasticity and bigger than the period with Skalak elasticity.

Investigation of performances and flow characteristics of two bi-directional pumps with different airfoil blades

Today, the most commonly used bi-directional airfoil in hydraulic machinery is the S-shaped airfoil(SA). A new bi-directional airfoil, obtained by lowering the bent airfoil camber and thickening the bone line bi-directionally, is proposed. Two bi-directional axial flow pumps, with the SA blades and the arc airfoil(AA) blades, respectively, were designed to verify the applicability of this airfoil. By comparing the hydraulic performances of the two pumps obtained from the experiments, and the cavitation performance and flow field of the two pumps obtained from numerical simulations, it was found that AA blades can improve both the hydraulic and cavitation performances under a low flow rate and near the best efficiency flow point(BEP), whether in forward or reverse operation for the bi-directional axial-flow pump. Furthermore, the hydraulic performance of the AA blade pump declines sharply in a large flow rate compared to that of the SA blade pump. The location and composition of the inhomogeneous flows inside the impellers of the two pumps are similar. However, the SA blades work on fluid, mainly at the front half of the blades, which is a distinctive feature from the AA blades and may be a universal phenomenon in all SA-type blades.

On the hyperbolicity of flows

Let X be a C1 vector field on a compact boundaryless Riemannian manifold M（dim M≥2）,and A a compact invariant set of X.Suppose that A has a hyperbolic splitting,i.e.,T∧M = Es Eu with Es uniformly contracting and Eu uniformly expanding.We prove that if,in addition,A is chain transitive,then the hyperbolic splitting is continuous,i.e.,A is a hyperbolic set.In general,when A is not necessarily chain transitive,the chain recurrent part is a hyperbolic set.Furthermore,we show that if the whole manifold M admits a hyperbolic splitting,then X has no singularity,and the flow is Anosov.