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The myocardial kinetic energy (KE) and its association with pulmonary regurgitation (PR) have yet to be investigated in repaired tetralogy of Fallot (rTOF) patients.To evaluate the adaptation of myocardial KE in rTOF patients by tissue phase mapping (TPM).Prospective.A total of 49 rTOF patients (23 ± 5 years old; male = 32), 47 normal controls (22 ± 1 year old; male = 29).3-T/2D dark-blood three-directional velocity-encoded gradient-echo sequence.Left and right ventricle (LV, RV) myocardial KE in radial (KEStudent's t test, multivariable regression. Statistical significance: P 0.05.In rTOF group, LV KEIn rTOF patients, the adaptation of the KE proportion occurred earlier than that of the KE amplitude, and the biventricular balance of %KE was disrupted. PR may cause differential KE adaptation in RV and LV. TPM-derived KE may be useful in investigation of myocardial adaptation in rTOF patients.2 TECHNICAL EFFICACY: Stage 3.

10.1119/10.0002764.1We investigate acoustic levitation in a vertical standing wave in an attempt to understand the basic physical mechanism responsible for this phenomenon. We find that a description in terms of a simple pressure force leads to the prediction of stable equilibria that occur slightly below the anti-nodes of the standing pressure wave. We then demonstrate that such a prediction is at odds with experimental data, which show that levitating particles come to rest slightly below the nodes of the standing pressure wave. Finally, we outline a theoretical approach based on fluid dynamics that correctly predicts the locations of the levitating particles, which leads to a simple qualitative description for this fascinating phenomenon.

Collaborative simulations was found more flexible and enhance students’ motivation. Although it is an effective way to implement science inquiry in classroom, the orchestration is complex and how the pedagogy influence students’ inquiry is still not clear. Therefore, this study address a light-weighted collaborative experiment pedagogy, which consists of computer simulations, teacher’s guidance and the whole-class reflection. To investigate the impact of such pedagogy on students’ inquiry performance and the science knowledge change, 33 8th grade students participated in this study. Results show that although the students design the experiment properly, their concept improvement is not significant which is not aligned with our expectation. Their inquiry process of the first time participating in light-weighted experiment demonstrated their inadequate ability of analyzing the experiment data, which led to obstacles of constructing knowledge by using computer simulation. Therefore, more de-briefing on data processing while conducting light-weighted experiment is suggested. Besides, whether a series of light-weighted experiment implementation enhance students’ performance is valuable to further investigate.

This study investigated students’ modeling progress and strategies in a problem-solving simulation game through content analysis, and through supervised and unsupervised lag sequential analysis (LSA). Multiple data sources, including self-report models and activity logs, were collected from 25 senior high school students. The results of the content analysis found that the problem-solving simulation game helped most of the students to reflectively play with the science problem and build a workable model to solve it. By using the supervised LSA, it was found that the students who successful solved the game frequently linked the game contexts with the physics terminologies, while those who did not solve the problem simply relied on the intuitive knowledge provided in the reference materials. Furthermore, the unsupervised LSA identified four activity patterns that were not noticed in the supervised LSA: the fragmented, reference material centered, reference material aided modeling, and modeling centered patterns. Each pattern has certain associations with certain problem-solving outcomes. The results of this study also shed light on the use of different analytics techniques. While the supervised LSA is particularly helpful for depicting a contrast of activity patterns between two specific student groups, the unsupervised LSA is able to identify hidden significant patterns which were not clearly distinguished in the pre-defined student groups. Researchers may find these analytics techniques useful for analyzing students’ learning processes.

Collaborative problem solving (CPS) is considered as one of the core competencies of the 21st century. Collaborative simulations which allow multiple students to participate in CPS activities in a shared simulation session are now increasingly applied to better facilitate these activities. However, the literature has shown that students' collaboration often does not lead to an effective solution to problems. Guided by the PISA CPS framework, this study thus aimed to analyze students collaboration patterns and problem solving strategies in solving a physics problem, and to identify significant patterns which may lead to a successful or unsuccessful outcome. Multiple data sources including group discussions, problem solving activities in a collaborative simulation, and open-ended questionnaire feedback from 30 high school students were analyzed using the lag sequential analysis technique. It was found that collaborative simulation has the potential to help students situate their discussion in a joint concrete problem space, facilitating their formation of a path to solve the problem. More importantly, the results showed significant differences between the successful and unsuccessful groups in terms of their collaboration patterns and problem solving strategies. A considerable portion of the students could only apply an intuitive trial-and-error strategy, and failed to solve the problem in the end. These students showed an inability to monitor and analyze the problem solving process, and were unable to transform their discussion into an executable plan to solve the problem. Those students who applied analytical reasoning strategies were more likely to achieve a successful problem solving outcome. The implications for educational practice are discussed, and the directions for future studies addressed. This study analyzed collaborative problem solving activities in a collaborative simulation context with LSA techniques.Significant differences in collaboration problem solving patterns were detected between successful and unsuccessful groups.A considerable portion of the students showed an inability to monitor and analyze the problem solving process.These students were unable to transform their discussion into an executable plan to solve the problem.Those students who applied analytical reasoning strategies were more likely to achieve a successful problem solving outcome.

We examine theoretically and experimentally the localized %and extended electrical modes existing in a bi-inductive electrical lattice containing a bulk or a surface capacitive impurity. By means of the formalism of lattice Green's functions, we are able to obtain closed-form expressions for the frequencies of the impurity (bound-state) eigenmodes and for their associated spatial profiles. This affords us a systematic understanding of how these mode properties change as a function of the system parameters. We test these analytical results against experimental measurements, in both the bulk and surface cases, and find very good agreement. Lastly, we turn to a series of quench experiments, where either a parameter of the lattice or the lattice geometry itself is rapidly switched between two values or configurations. In all cases, we are able to naturally explain the results of such quench experiments from the larger analytical picture that emerges as a result of the detailed characterization of the impurity-mode solution branches., Comment: 9 pages, 11 figures

Collaborative problem solving is a core ability that has been highly valued in recent years. Collaborative problem solving activities allow learners develop collaboration skills. In science education, collaborative learning with simulations enables learners to manipulate a science problem to explore scientific concepts. However, the collaboration during such a learning context is a complicated process and researchers face difficulties in understanding learners’ mental effort in using the simulations. The use of dual eye-tracking techniques is helpful to uncover learners’ visual attention, and thus to better analyze student collaboration in activities. In this paper, the research focus on learners’ difficulties when they learn together with the simulation in different places. The results show that the techniques are helpful to identify the subtle interaction problem including the problem of lacking coordination, the process misunderstanding problem, and misunderstanding in partners’ attention. Educators may need to address these problems when simulations are applied to support remote collaborative science learning.

Recent advancements in Web and HTML5 techniques have made collaborative simulations able to support a shared workspace and more synchronous collaboration in a single simulation. However, previous studies show divergent findings regarding the effects of the new features of collaborative simulations. To better understand the affordances and limitations of collaborative simulations, this study analyzed how 64 students learned in two different collaborative learning settings: individual-based simulation and collaborative simulation. To better reveal how students attended to different parts of the simulation, the researchers collected eye movement data and analyzed students’ discourse, perceptions of collaboration and learning performance. The findings revealed that the two groups demonstrated similar levels of learning gains. However, the students who used the collaborative simulation displayed lower levels and less frequency of individual attention to the simulation than those using the individual-based simulation. However, the joint attention and discourse analysis suggests that students learning with the collaborative simulation are more likely to engage in effective collaborative learning while demonstrating more constructive discourse threads than those using the individual-based simulation. The findings support that the collaborative simulations transformed the learning experience into a cohesive collaborative learning process. This study also found that the relationship between the joint attention and the discourse features as well as the perceived collaborative experience are not decisive but are influenced by the features of the collaborative learning environment. This article discusses the implications of the use of collaborative simulations and eye movement for supporting collaborative learning, and addresses the direction for future studies.

The study investigates the effect of an interactive simulation with embedded inquiry support, which was seamlessly embedded within the simulation, on students' scientific literacy and school science achievement, and explores the relationships among prior school science achievement, inquiry processes and scientific literacy. A total of 49 eighth-grade students at a public junior high school in northern Taiwan participated. Data collected include the students' pre- and post-scores for school science achievement, logging data that indicate their inquiry processes, and pretest, posttest, and delayed-test data that measure their scientific literacy. The results provide evidence that the designed simulation and inquiry support had a long-term effect on the students' scientific literacy. Replacing conventional teaching with inquiry activities did not harm the students' school science achievement performances. Moreover, compared to school science achievement, students' scientific literacy seems a better predictor of their inquiry behavior, especially in the aspect of making conclusions. Analyses of the students’ inquiry processes indicate that the so-called low science achieving students conducted more data analyses than the other students, and demonstrated adequate inquiry engagement. The students with middle level school science achievement demonstrated the most active engagement in inquiry and showed good gains of scientific literacy after the learning. These results indicate that a guided inquiry learning environment can support students with different levels of school science achievement to highly engage in science inquiry. Implications and future studies are discussed.

Pedagogical design for science learning in classrooms often involves tension between the scientific community expectations and traditional curricular expectations. To address this issue, this study proposed a light-weight inquiry activity that can be pragmatically implemented in regular classrooms based on the minimalism principle and the teacher-led collaboration principle. Data gathered from 49 middle school students indicated that after learning in the light-weight inquiry condition, students demonstrated significant enhancements in the target science knowledge. In particular, the students in the light-weight inquiry condition displayed significantly higher levels of enhancement in scientific literacy than those who learned in the traditional lecturing condition. Furthermore, the students perceived a higher level of deep motivation and strategy but a lower level of memorizing science facts and calculating and practicing when they learned in the light-weight inquiry condition. The proposed pedagogical design demonstrated a positive impact on the learning of science knowledge, scientific literacy, and conceptions of learning and approaches to learning science. However, an unexpected effect was also observed, showing that the light-weight inquiry activity might also trigger surface motivation reflecting students' fear of failure in tests and the orientation to meet external expectations. The implications of the educational practice are discussed, and directions for future studies are also addressed.

Control of the polymorphism of organic semiconductor films is very important in optoelectronic devices, such as organic thin-film transistors, solar cells, and organic light-emitting diodes. Here, we show the use of polyimide nanogratings (PI-NGs) patterned by nanoimprint lithography to control the polymorphism of deposited pentacene films. Interestingly, a new crystalline phase is first found in the pentacene thin-film formed on the PI-NGs. This new phase, with a d-spacing of 1.35 nm, is more stable than the bulk and thin-film phases in the pentacene film, discussed in terms of X-ray diffraction (XRD) measurements and quantum theory calculations. The response mechanism of the formation of this new phase is characterized by XRD and atomic force microscopy; the polymorphism and surface morphology show a strong dependence on the width of PI-NGs. The size-dependent PI-NG responses of the pentacene film can also control the phase transition from the thin-film to the bulk phase.

This study focuses on the microstructural modifications of regioregular poly(3-hexylthiophene) (rr-P3HT) in the small active channel of thin-film transistors (TFTs) during operations. Polarized abs...

UV-curable organic/inorganic hybrid nanocomposites have been successfully synthesized with polymer monomers (tetramethoxysilane (TMOS)/3-glycidoxypropyl-trimethoxysilane (GPTMS)) nano-fillers (silica/alumina), curing agents (bisphenol A (BPA)), and photoinitiators (triaryl sulfonium hexafluoroantimonate (TSH)) by in situ polymerization. Their thermal stability, coefficient of thermal expansion (CTE), adhesion strength, and gas barrier capability have also been investigated with thermogravimetry analysis (TGA), thermomechanical analysis (TMA), micro-computer universal testing machine and moisture penetration tests. Experimental results indicate that nano-fillers are completely homogeneously dispersed in the polymer matrices and the increase of nano-fillers in the nanocomposites causes the raise of decomposition temperature (Td) as well as gas resistance and the reduction of CTE as well as adhesion strength. Because lab-made organic/inorganic hybrid nanocomposites have been discovered to exhibit excellent gas barrier properties, we have also applied them for the encapsulation of organic light-emitting diodes (OLEDs) and flexible OLEDs. With lab-made nanocomposite d, the lifetimes of OLEDs and flexible OLEDs can be successfully lengthened to 92 and 36 h, respectively, whereas those of OLEDs and flexible OLEDs without encapsulation are 11 and 7 h, respectively. © 2008 Elsevier B.V. All rights reserved.

This work demonstrates the use of lithium fluoride (LiF) as a passivation layer and a newly developed UV glue for encapsulation on the LiF passivation layer to enhance the stability of organic light-emitting devices (OLEDs). Devices with double protective layers showed a 25-fold increase in operational lifetime compared to those without any packaging layers. LiF has a low melting point and insulating characteristics and it can be adapted as both a protective layer and pre-encapsulation film. The newly developed UV glue has a fast curing time of only 6 s and can be directly spin-coated onto the surface of the LiF passivation layer. The LiF thin film plus spin-coated UV glue is a simple packaging method that reduces the fabrication costs of OLEDs.

This study presents a partition decoding algorithm for an (mN, mK) binary image of an (N, K) Reed Solomon code over GF(2 m ). A proposed partition decoding algorithm includes several steps. Firstly we compute m's segmental reliability values of a received subvector of length N and determine which one with the least segmental reliability value. A permutation is performed on a binary generator matrix of an RS code and a received vector, which are then partitioned into two submatrices and two subvectors. The first subvector of length N(m - 1) associate with the first submatrix and the second subvector with the least segmental reliability value relates to the second submatrix. Secondly, an MLD algorithm based on the first submatrix is employed to decode the first subvector. Thirdly, an MLD algorithm based on a BCH generator matrix is employed to decode the second subvector. A codeword is finally outputted after performing the inverse permutation on a concatenation of code vectors decoded from these two decoding. The error coefficient and minimum Hamming distance of the code sequences generated in the first submatrix are fewer than those of a corresponding binary image. Simulation results show that at low and medium SNRs, the effect of error coefficient becomes more significant than that of minimum Hamming distance. Minimum Hamming distances and error coefficients of code sequences generated in the first submatrices and their corresponding binary images have been explored in this work. For (60,36,7)RS (b) , (155,125,7)RS (b) , (155,105,11)RS (b) and (889, 847,7))RS (b) being binary images of (15,9,7)RS, (31,25,7)RS, (31,21,11)RS and (127,121,7)RS codes respectively, with BPSK signaling over AWGN channels, the decoding performances of proposed partition decoding algorithm are a little poorer than those of MLD [10] by 1.0 to 1.4dB at BER 10 -5 , but better than those of GMD decoding [1] by 0.8 to 1.1 dB. For SNR of 5 dB, proposed partition decoding algorithm only takes 50% to 60% amount of bit operations of an MLD [10]. Under a constraint of decoding complexity, proposed partition decoding algorithm may be a solution to decode binary images of long RS codes, which provides superior performance to GMD decoding with much lower complexity than an MLD.

Dusty plasma is a four-component plasma system with fine particles suspended in a gaseous background with electrons, ions, and neutrals. The dust particles are usually negatively charged. The capability of forming fine particles in discharges opens a new window for various applications. The large mass and charges drastically alter the nature of the background plasma and generate many interesting collective behaviors. In this paper, we briefly review the recent researches on the fine particles in dusty plasmas, including the forces on the single particles, particle formation mechanisms, particle manipulation and removal, dust plasma crystals and liquids, and collective waves in dusty plasmas.

The derivative of C60, i.e., PCBM, and P3HT (3-hexylthiophene) were dissolved in chloroform:dichlorobenzene mixed solvent, then spin-coated as the active layer for organic solar cells (OSC). The experimental parameters were studied carefully to obtain the optimum power conversion efficiency (PCE), including the solvent mixing ratio, spin-coating speed, annealing conditions for the active layer, etc. The OSC devices were packaged with glass and a newly developed UV-glue to improve the lifetime and PCE. Dichlorobenzene solvent has great effect upon the PCE. Changing the spin-coating speed and increasing the number of steps increased the PCE apparently to 1.4%.

In this work, we prepared an organic phosphor and investigated its thermal as well as fluorescent properties. The experimental results reveal that lab-made organic phosphor exhibits excellent thermal stability (Decomposition temperature (Td) = 374 °C) and good fluorescent quantum yield (Φ = 0.88). The organic phosphor was then coated onto the blue LED chip to form a white light-emitting diode. The size of blue LED die used throughout this work was 15 mil square and the dominated wavelength was 460 nm. For the package process, the organic phosphor was firstly mixed with the epoxy and dipped it into the LED bowl of lead frame. Secondly, the pure epoxy resin was full-filled within the lamp model. For the measurement of spectrum and the C.I.E. value, it was found that the near white weight proportional of the epoxy resin A, B and the organic phosphor were 1 : 1 : 0.1.

The system complexity, as calculated from correlation dimension, embedded in each layer and its modulation by specific inputs and general excitatory state are not yet known. The aims of present study were to estimate the system complexity across the cortical layers by analyzing intracortical EEG signals using a nonlinear analytical method, and to identify how layer-related complexity varies with the alteration of thalamic input and brain state. Male Sprague–Dawley rats were anesthetized under l% halothane. Sixteen channels of evoked or spontaneous EEG signals were recorded simultaneously across the six cortical layers in the somatosensory cortex with a single Michigan probe. The system complexity was assessed by computing correlation dimension, D2, based on the Nonlinear Time Series Analysis data analysis program. Cortical layer IV exhibited a D2 value, 3.24, that was significantly higher than that of the other cortical layers. The D2 values in layers IV and II/III were significantly reduced after reversible deactivation of the ventral posterior lateral thalamic nucleus. D2 decreased with increases in administered halothane concentration from 0.75% to 2.0%, particularly in layer IV. The present findings suggest that cortical layer IV maintains a higher complexity than the other layers and that the complexity of the mid-cortical layers is subject to regulation from specific thalamic inputs and more sensitive to changes in the general state of brain excitation.

The performance of bilayer heterojunction, pentacene and perylene tetracarboxylic diimide organic solar cells (OSC) is dramatically enhanced by performing nanoimprinting on the hole transport layer in which poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) nanogratings are built. A standard OSC embeded with PEDOT:PSS gratings enables photocarriers to move toward electrodes. In particular, the visualization of morphologies for these heterojunction layers reveals pillar-like grains that are induced by the geometric effect of PEDOT:PSS gratings. Toghther with analyzing absorption and time-resolved photoluminescence spectra, a consistent correlation between OSC performance, photophysical data, and pillar-like morphology has been obtained for the device with imprinted PEDOT:PSS nanogratings.

The derivatives of C60, [6,6]-phenyl C61-butyric acid methyl ester (PCBM), and 3-hexylthiophene (P3HT) were dissolved in o-dichlorobenzene (DCB) solvent, and then spin-coated as an active layer for polymer solar cells. The experimental parameters including the spin-coating speed and drying conditions for the active layer, were studied carefully to obtain the optimum power conversion efficiency (PCE). In the active layer drying procedure, the DCB solvent saturated/unsaturated vapor pressure was adjusted by controlling the amount of solvent at a half-open capacity. The DCB solution was used to enhance the self-organization of the active layer of P3HT and to reduce the number of pure PCBM clusters. In the DCB optimum solution, the PCE of a polymer solar cell can be increased from 1.36 to 1.79%. The structure corresponds to a nano-to-micron scale ordering in the unsaturation-treatment films. In the optimum unsaturation procedure, the PCE of a polymer solar cell can be increased from 1.79 to 2.53%. Using two steps with optimum rotation speeds in the active layer spin-coating, the surface uniformity can be improved, with the PCE increased from 2.53 to 3.13%.

Polymorphism control of organic semiconductor films greatly affects optoelectronic device performance. The thin-film phase is always the dominant phase in the early growth of pentacene films; however, the performance of the bulk phase is superior to that of the thin-film phase. In the present study, a nanoimprinted polyimide layer is used to induce the growth of the bulk phase in the early stage. The bulk phase appears in the initial few layers and its dominance of the polymorphisms in the pentacene film increases with increasing thickness. The mechanism of the phase transformation is explained.

The charge carrier transport efficiency and issues of patterning in organic semiconductors limit the potential range of microelectronic and optoelectronic applications of organic devices in nanoscale. We demonstrate high-performance organic field-effect transistors (OFETs) with a mobility of approximately 2.5 cm2/V s using nanogroove gate-dielectrics formed by nanoimprinting. The preferred flow of charge carriers in OFETs parallel to the nanogrooves yields a high mobility anisotropic ratio (above 220), providing a built-in autopattern organic semiconductor function with nanoscale resolution. This nanostructure embedded device has great potential for use in the manufacture and lithography-free patterning of organic semiconductor films in integrated circuits.

A photosensitive polyimide (PSPI) is synthesized to serve as the gate dielectric in organic thin-film transistors (OTFTs). A method to control the charge density within the channel of the OTFT using the PSPI on a silicon dioxide gate dielectric is proposed. The surface energy, surface carriers, and capacitance of gate dielectrics can be tuned by varying irradiation doses of UV light on the PSPI surface to create ultrahigh performance pentacene-based OTFTs with an average field-effect mobility (μ) of above 6.0 cm2/Vs. The correlation between the surface energy of the PSPI films and the μ value of OTFT devices is investigated. Moreover, the impact of gate-dielectric properties on the structural properties of pentacene films is closely related to the electrical characteristics of OTFTs. The results of contact angle, X-ray diffraction, electrostatic force microscopy, and micro-Raman spectroscopy measurements indicate that the surface energy and doping carriers coming from the PSPI film play important roles in the carrier transport of pentacene film for OTFT applications.

The microscopic visco-elastic motion of a quasi-2D dusty plasma liquid confined to a width of about 15 interparticle distances under square stress pulses shorter than thermal relaxation time from a chopped laser beam is investigated experimentally. The stress-enhanced excitations of hopping vortices are responsible for particles in the laser driven zone reaching, after a higher initial velocity, a constant nonzero terminal forward velocity and partial plastic deformation through the loss of the structure memory. The driven particles around domains with caged shear motion still partially keep the structural memory and demonstrate partial elastic backwards motion with exponential relaxation after turning off the laser.

The stress induced microscopic responses of dust particles in strongly coupled dusty plasma liquids suspended in plasma traps are investigated experimentally. Narrow laser beams are used to generate stress on dust particles through optical pressure. Assisted by background thermal fluctuations, chaotic micro-vortices with decaying intensities from the laser beam are generated. The forward transport and transverse diffusion rate are enhanced and show nonlinear reponse to the external stress. Visco-elastic response is observed for an elongated liquid cluster driven by a periodically chopped laser beam. The shear wave is damped.