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991.
计算思维是STEM问题解决中的一项关键能力,培养学生的计算思维已逐渐成为STEM教育的重要目标。然而当前如何在STEM工程设计教学中培养学生的计算思维,还有待深入探索。面向计算思维培养的STEM工程设计教学模式以计算思维、STEM学科内容知识以及教学法的整合为核心,通过工程设计发挥"系统流程"优势,将科学、技术与数学相关活动整合在一起,让学生在"需要知道"和"需要做"的循环过程中感知情境性问题,解决挑战性任务。该模式在STEM课程"植物工厂"中的教学应用表明:将计算思维的概念与实践融入STEM工程设计的各个环节,能显著提升学生的STEM态度和计算思维能力,并且STEM态度对计算思维具有预测作用。未来,通过STEM教育发展计算思维将成为一种跨学科的思维实践,基于证据的多元评价方式将有利于STEM教育中计算思维的培养。 相似文献
992.
借助家庭抗逆力理论探究寒门大学生家庭抗逆力的建构情况和实现学业逆袭的动态机制。发现寒门学子在学业逆袭过程中并不一定具有一致的家庭正向性支持,相反,这个过程呈现曲折性和多样化的样态:对于始终具有强家庭抗逆力的寒门学子来说,家庭信念、组织以及沟通系统中父母与子女的合力有利于提升个人奋斗力从而实现学业逆袭;弱抗逆力的家庭普遍缺乏正向情绪的积累,部分家庭通过和解与转变也能增强抗逆力,而消极应对的家庭最终在重要他人介入和自身韧性的支撑下达到积极结果。家庭物质支持和对高等教育价值的认可是实现学业逆袭的必要条件;正向沟通和积极情感积累是实现强抗逆力的重要支撑,这是寒门家庭容易忽视却必须重视的。 相似文献
993.
994.
计算机通信节点部署随机性较大,热点周边存在随机的窄带干扰信号。其中,较强的窄带干扰会严重影响计算机正常通信。为解决这一问题,提出了一种基于通信信息模糊一致的计算机优化通信算法,设计了通信中的模糊矩阵,利用矩阵一致性判断方法,在变换域实现对干扰信号的识别与滤除,并且无失真地恢复出原始信号。仿真分析结果表明,该算法下,计算机能够实现识别并滤除窄带干扰,很大程度上降低计算机通信的误码率。 相似文献
995.
996.
Young Sik Kang Jinyoung Min Jeoungkun Kim Heeseok Lee 《International Journal of Information Management》2013
Individuals with a positive evaluation of a target system are likely to continue using the system, and this sustained use is likely to result in continued use. This target-oriented perspective has served as a major conceptual framework for understanding users’ behaviors in online contexts. The primary objective of this paper is to address two additional perspectives—alternative- and self-oriented perspectives—for a firmer understanding of continued use in the context of social network sites (SNS). A research model is built by employing regret and self-image congruity to represent these two perspectives. The model also examines the condition under which habits are formed and how this automatic mechanism influences the dynamics of the nomological network between intentions and behaviors. The analysis results of two rounds of surveys for capturing the actual link between intentions and behaviors indicate that regret and self-image congruity can play crucial roles in post-adoption phenomena in the context of SNS. 相似文献
997.
998.
生态位理论及其对档案馆科学发展的启示 总被引:3,自引:0,他引:3
文章在借鉴生态位理论已有研究成果的基础上,详细阐述了生态位理论对档案馆科学发展的重要启示. 相似文献
999.
The accurate viscosity measurement of complex fluids is essential for characterizing fluidic behaviors in blood vessels and in microfluidic channels of lab-on-a-chip devices. A microfluidic platform that accurately identifies biophysical properties of blood can be used as a promising tool for the early detections of cardiovascular and microcirculation diseases. In this study, a flow-switching phenomenon depending on hydrodynamic balancing in a microfluidic channel was adopted to conduct viscosity measurement of complex fluids with label-free operation. A microfluidic device for demonstrating this proposed method was designed to have two inlets for supplying the test and reference fluids, two side channels in parallel, and a junction channel connected to the midpoint of the two side channels. According to this proposed method, viscosities of various fluids with different phases (aqueous, oil, and blood) in relation to that of reference fluid were accurately determined by measuring the switching flow-rate ratio between the test and reference fluids, when a reverse flow of the test or reference fluid occurs in the junction channel. An analytical viscosity formula was derived to measure the viscosity of a test fluid in relation to that of the corresponding reference fluid using a discrete circuit model for the microfluidic device. The experimental analysis for evaluating the effects of various parameters on the performance of the proposed method revealed that the fluidic resistance ratio (RJL/RL, fluidic resistance in the junction channel (RJL) to fluidic resistance in the side channel (RL)) strongly affects the measurement accuracy. The microfluidic device with smaller RJL/RL values is helpful to measure accurately the viscosity of the test fluid. The proposed method accurately measured the viscosities of various fluids, including single-phase (Glycerin and plasma) and oil-water phase (oil vs. deionized water) fluids, compared with conventional methods. The proposed method was also successfully applied to measure viscosities of blood with varying hematocrits, chemically fixed RBCS, and channel sizes. Based on these experimental results, the proposed method can be effectively used to measure the viscosities of various fluids easily, without any fluorescent labeling and tedious calibration procedures. 相似文献
1000.
Understanding the mechanical properties of optically transparent polydimethylsiloxane (PDMS) microchannels was essential to the design of polymer-based microdevices. In this experiment, PDMS microchannels were filled with a 100 μM solution of rhodamine 6G dye at very low Reynolds numbers (∼10−3). The deformation of PDMS microchannels created by pressure-driven flow was investigated by fluorescence microscopy and quantified the deformation by the linear relationship between dye layer thickness and intensity. A line scan across the channel determined the microchannel deformation at several channel positions. Scaling analysis widely used to justify PDMS bulging approximation was allowed when the applied flow rate was as high as 2.0 μl/min. The three physical parameters (i.e., flow rate, PDMS wall thickness, and mixing ratio) and the design parameter (i.e., channel aspect ratio = channel height/channel width) were considered as critical parameters and provided the different features of pressure distributions within polymer-based microchannel devices. The investigations of the four parameters performed on flexible materials were carried out by comparison of experiment and finite element method (FEM) results. The measured Young''s modulus from PDMS tensile test specimens at various circumstances provided reliable results for the finite element method. A thin channel wall, less cross-linker, high flow rate, and low aspect ratio microchannel were inclined to have a significant PDMS bulging. Among them, various mixing ratios related to material property and aspect ratios were one of the significant factors to determine PDMS bulging properties. The measured deformations were larger than the numerical simulation but were within corresponding values predicted by the finite element method in most cases. 相似文献