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项目外源信息的收集对于项目管理来说意义重大，传统的收集方法存在着诸多的不足，本文提出运用现代信息技术来收集项目外源信息的观点，并阐述了该种方法的优势，技术可行性，以及运用该种方法的途径。 相似文献
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《内蒙古科技与经济》2015,(8)
在分析电火花加工原理及电极损耗对工件精度影响的基础上,借助慢走丝电火花线切割电极原理,提出了移动更新式电极的理论依据,并对原有电火花设备进行必要改装,配置了移动电极及辅助部件,以便减少电火花加工电极的损耗。通过分析、实验验证该方法合理适用,能够提高电极损耗对电火花加工精度的影响。 相似文献
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电火花加工是在一定介质中通过工具电极和工件电极间的脉冲放电的电蚀作用,对工件进行加工的方法。因电火花加工具有其他加工方法无可替代的特最,它已成为模具制造中较为先进的加工方法。本文阐述了数控电火花切割加工的基本原理,主要对设备、电极丝及应用范围进行了分析。 相似文献
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原电池电极反应式的书写历来是高考中的热点话题,对于学生来说,电极反应式的书写一直是一大难点,如何较轻松的解决这一难点,关键是掌握电极反应式的书写方法。 相似文献
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提出了基于支持向量机以及量化容差关系的数据补齐模型,针对不同区域数据塑造差异残缺数据的支持向量机预测模型,实现对跨区域差异残缺数据的预测,采用RBF神经网络修补残缺数据,通过基于量化容差关系的残缺数据补齐方法对残缺数据进行深度补齐,实现对跨区域差异残缺数据的进一步优化。实验结果显示了该种方法进行的跨区域差异残缺数据补齐效果优于传统方法。该种方法具有较高的补齐准确率,可获得满意的修补效果。 相似文献
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This paper presents a field-flow method for separating particle populations in a dielectrophoretic (DEP) chip with asymmetric electrodes under continuous flow. The structure of the DEP device (with one thick electrode that defines the walls of the microfluidic channel and one thin electrode), as well as the fabrication and characterization of the device, was previously described. A characteristic of this structure is that it generates an increased gradient of electric field in the vertical plane that can levitate the particles experiencing negative DEP. The separation method consists of trapping one population to the bottom of the microfluidic channel using positive DEP, while the other population that exhibits negative DEP is levitated and flowed out. Viable and nonviable yeast cells were used for testing of the separation method. 相似文献
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Electrorotation is widely used for characterization of biological cells and materials using a rotating electric field. Generally, multiphase AC electric fields and quadrupolar electrode configuration are needed to create a rotating electric field for electrorotation. In this study, we demonstrate a simple method to rotate dielectrophoretically trapped microparticles using a stationary AC electric field. Coplanar interdigitated electrodes are used to create a linearly polarized nonuniform AC electric field. This nonuniform electric field is employed for dielectrophoretic trapping of microparticles as well as for generating electroosmotic flow in the vicinity of the electrodes resulting in rotation of microparticles in a microfluidic device. The rotation of barium titanate microparticles is observed in 2-propanol and methanol solvent at a frequency below 1 kHz. A particle rotation rate as high as 240 revolutions per minute is observed. It is demonstrated that precise manipulation (both rotation rate and equilibrium position) of the particles is possible by controlling the frequency of the applied electric field. At low frequency range, the equilibrium positions of the microparticles are observed between the electrode edge and electrode center. This method of particle manipulation is different from electrorotation as it uses induced AC electroosmosis instead of electric torque as in the case of electrorotation. Moreover, it has been shown that a microparticle can be rotated along its own axis without any translational motion. 相似文献
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Qiuxu Wei Wenliang Yao Le Gu Bolin Fan Yongjia Gao Li Yang Yingying Zhao Chuncheng Che 《Biomicrofluidics》2021,15(1)
With widespread research studies on electrowetting-on-dielectric (EWOD) for droplet manipulation in the field of lab-on-a-chip, how to improve the driving capability of droplets has increasingly attracted enormous interest. Aiming to decrease driving voltages and improve driving effectiveness, this paper studies the modeling, simulation, and optimization of EWOD devices. The theoretical model is refined mainly in consideration of the saturation effect of the contact angle and then verified by both simulation and experiments. As a design guide to decrease the driving voltage, a theoretical criterion of droplet splitting, the most difficult one among four basic droplet manipulations, is developed and then verified by experimental results. Moreover, a novel sigmoid electrode shape is found by the optimization method based on finite element analysis and achieves better driving effectiveness and consistent bidirectional driving capability, compared with the existing electrode shapes. Taken together, this paper provides an EWOD analysis and optimization method featuring a lower voltage and a better effectiveness and opens up opportunities for optimization designs in various EWOD-based applications. 相似文献
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The present study uses the dielectrophoresis (DEP) and electrothermal (ET) forces to develop on-chip micromixers and microconcentrators. A microchannel with rectangular array of microelectrodes, patterned either on its bottom surface only or on both the top and the bottom surfaces, is considered for the analysis. A mathematical model to compute electrical field, temperature field, the fluid velocity, and the concentration distributions is developed. Both analytical and numerical solutions of standing wave DEP (SWDEP), traveling wave DEP (TWDEP), standing wave ET (SWET), and traveling wave ET (TWET) forces along the length and the height of the channel are compared. The effects of electrode size and their placement in the microsystem on micromixing and microconcentrating performance are studied and compared to velocity and concentration profiles. SWDEP forces can be used to collect the particles at different locations in the microchannel. Under positive and negative DEP effect, the particles are collected at electrode edges and away from the electrodes, respectively, irrespective of the position, size, and number of electrodes. The location of the concentration region can be shifted by changing the electrode position. SWET and TWET forces are used for mixing and producing concentration regions by circulating the fluid at a given location. The effect of forces can be changed with the applied voltage. The TWDEP method is the better method for mixing along the length of the channels among the four options explored in the present work. If two layers of particle suspension are placed side by side in the channel, triangular electrode configuration can be used to mix the suspensions. Triangular and rectangular electrode configurations can efficiently mix two layers of particle suspension placed side-by-side and one-atop-the-other, respectively. Hence, SWDEP forces can be successfully used to create microconcentrators, whereas TWDEP, SWET, and TWET can be used to produce efficient micromixers in a microfluidic chip. 相似文献
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以硫脲作为硫源,在瓦特浴体系中通过电沉积方法获得Ni-S合金电极。阐述了电沉积过程中各工艺条件(硫脲浓度、电流密度、pH值及温度)对镀层中S含量的影响,指出硫脲浓度和电流密度为Ni-S合金镀层中S含量的主要影响因素,并用恒流充放电实验研究了电极的电化学性能。 相似文献
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随着我国国民经济的不断发展,焊接技术广泛应用于机械制造、车辆、造船、冶金、矿藏等领域,因此在很多的职业类院校中都开设了手工电弧焊的专业课程.在教学的过程中手工电弧焊的焊接参数的选择是教学重点以及难点.本文在研究手工电弧焊的焊接参数选择的基础之上分析了在手工电弧焊的焊接参数教学中遇到的难题,重点分析了在实训教学过程中手工电弧焊焊接参数的应用. 相似文献
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电芬顿法(Electro-Fenton Process)处理废水 总被引：2，自引：0，他引：2
电芬顿法(electro-Fenton)是在Fenton试剂的基础上,在二价铁离子(Fe2+)和过氧化氢(H2O2)作用下,产生强氧化性的羟基自由基(●OH)并由其氧化难降解废水,其中Fe2+和H2O2分别由电化学过程产生。本文概述了电芬顿过程的基本原理,通过介绍国内外电芬顿的发展情况,详细介绍了电芬顿的影响因素,包括pH、阴极电极、催化剂及其他因素等,并展望了其未来的发展方向。 相似文献