Dual-mode on-demand droplet routing in multiple microchannels using a magnetic fluid as carrier phase     

Jitae Kim  June Won  Simon Song 《Biomicrofluidics》2014,8(5)

We present dual-mode, on-demand droplet routing in a multiple-outlet microfluidic device using an oil-based magnetic fluid. Magnetite (Fe₃O₄) nanoparticle-contained oleic acid (MNOA) was used as a carrier phase for droplet generation and manipulation. The water-in-MNOA droplets were selectively distributed in a curved microchannel with three branches by utilizing both a hydrodynamic laminar flow pattern and an external magnetic field. Without the applied magnetic field, the droplets travelled along a hydrodynamic centerline that was displaced at each bifurcating junction. However, in the presence of a permanent magnet, they were repelled from the centerline and diverted into the desired channel when the repelled distance exceeded the minimum offset allocated to the channel. The repelled distance, which is proportional to the magnetic field gradient, was manipulated by controlling the magnet''s distance from the device. To evaluate routing performance, three different sizes of droplets with diameters of 63, 88, and 102 μm were directed into designated outlets with the magnet positioned at varying distances. The result demonstrated that the 102-μm droplets were sorted with an accuracy of ∼93%. Our technique enables on-demand droplet routing in multiple outlet channels by simply manipulating magnet positions (active mode) as well as size-based droplet separation with a fixed magnet position (passive mode).  相似文献   

Joseph Chamberlain and Free Education in the Election of 1885     

Alan Simon 《History of education》2013,42(1):56-78

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The Mexico City conference     

Simon Romero-Lozano 《Prospects》1980,10(2):235-240

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The warrants for basic research     

Simon Rottenberg 《Minerva》1966,5(1):30-38

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The Effects of Late Arts Education on Adults with Early Visual Disabilities     

Simon Hayhoe 《Educational Research and Evaluation》2013,19(3):229-249

In this study, non-participant observations of visually disabled adult students in extra mural arts education are analysed through Walter Doyle’s theory of ambiguity and risk in classroom tasks. This study finds these students attempted to avoid activity, or re-negotiate lecturers’ expectations, when their performance became especially threatening to their self-esteem. Additionally, it was found that lecturers were often reluctant to push their students as soon as they realised this risk to them. These results appear to show a phenomenon similar to learned helplessness.  相似文献   

The kite as an instrument of meteorological research     

Chas.F. Marvin 《Journal of The Franklin Institute》1899,148(4):241-259

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The industrial lot and its sampling implications     

Leslie E. Simon 《Journal of The Franklin Institute》1944,237(5):359-370

It is shown that wrong inferences are drawn from samples because of failure to understand what constitutes a lot and because of failure to verify the existence of a lot in the practically useful sense. Time-tried methods of making valid inferences from samples without increased cost are pointed out.  相似文献   

Exploring the Causal Effect of Interpretation Bias on Attachment Expectations          下载免费PDF全文

Simon De Winter  Elske Salemink 《Child development》2017,88(1):131-140

Attachment theory implies that children's inclination to interpret attachment figures behavior as supportive and available causally influences children's trust in their attachment figure's availability. An experiment was conducted to test whether training children (8–12 years old) to interpret ambiguous interactions with their mothers in a more secure way increases their trust in their mother's availability. Participants (N = 49) were randomly assigned to either a secure condition to train children to interpret their mother's behavior as supportive or a neutral placebo condition, where interpretations were unrelated to maternal support. Results supported the hypothesis: After the secure training, children interpreted maternal behavior more securely and trusted more in her availability. This suggests that attachment‐related processing biases causally affect attachment expectations.  相似文献   

Vygotsky’s sociocultural theory in the context of globalization     

Simon Marginson  Thi Kim Anh Dang 《Asia Pacific Journal of Education》2017,37(1):116-129

The article reviews the social-educational theorization of the early Soviet psychologist L. S. Vygotsky (1896–1934) in the light of the impact of communicative globalization in educational practice. Vygotsky proposed four “genetic domains” for investigating higher cognitive processes: the phylogenetic (humans undergoing natural evolution), the cultural-historical (social activity of humans), the ontogenetic (individual lifespan), and the microgenetic (immediate events). Vygotskian sociocultural theory is widely used in educational research, especially Vygotsky’s notion of mediated development via tools and signs. Since Vygotsky, communicative globalization has transformed educational potentials. Nevertheless, provided adjustments are made to Vygotsky’s genetic method to incorporate time-space compression, the mutual presence of the genetic domains, and the glonacal heuristic, Vygotskian theory continues to be useful in socially-situated investigations of educational development and transformation, and opens another way into the global, for example investigation of the role of global mediation in learning.  相似文献   

Student & tutor consensus: a partnership in assessment for learning     

James Thompson  Don Houston  Kathryn Dansie  Timothy Rayner  Timothy Pointon  Simon Pope 《Assessment & Evaluation in Higher Education》2017,42(6):942-952

The mistakes made when attempting tasks often prove to be some of the most invaluable learning experiences. Despite this, outcome and results driven assessment formats largely penalise student performance errors or reward students who succeed by chance. The consequences of this paradigm are visible effects on student relationships with assessment. The student–tutor consensus approach to assessment was introduced to capture student learning achieved ‘from’ assessment to complement the measurement of performance outcomes. This approach parallels student and tutor judgement in a grade negotiation, affording the student an opportunity to share with their assessor what they have learned from the assessment activity. This student self-awareness was then considered alongside the conventional outcome-based score awarded by the tutor to generate a final grade for the assessed activity. Our study evaluated the perceptions of 90 undergraduate students enrolled in the bachelor of paramedic studies, who participated in this novel assessment approach as part of a final-year capstone topic. The results comprehensively indicated value for all aspects of the assessment approach, as well as a recognition that the skills will be useful in their future professional roles.  相似文献