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This article proposes the combination of filament-heating and cavity-driven circuit with gain-frequency regulation control for magnetrons. This article is motivated because some existent magnetron-driven systems often adopted two resonant circuits individually for filament heating and cavity driving, resulting in limited flexibility of power delivery and modulation. Therefore, this article develops an integrated resonant power circuit that excels at the capability improvement of filament heating and cavity driving in the same time such that the design process and power conversion can be simplified while the output power is effectively induced. Meanwhile, by considering that the microwave source emission in the magnetron is often affected by the variation of internal impedance, this article includes a gain-frequency tracking control. Through this way of controller design, both heating power and cavity power are found to be well regulated and the constant-power operation can be better achieved. To confirm the effectiveness of this magnetron-driven design, both circuit simulation and hardware realization are accomplished. Analysis results and experimental outcome support the practicality of the approach, benefiting the realization of microwave energy applications.

Live video streaming has become one of the key applications in mobile wireless networks. To offload the bandwidth requirement in both backhaul and radio access networks, the integration of Mobile Edge Computing (MEC) and multicasting have become a natural candidate. However, less attention has been paid to the user Quality of Experience-driven (QoE-driven) approach to optimize the radio resource management of multicasting in mobile wireless networks. In this work, we study the optimal radio resource management, including modulation and coding scheme (MCS) selection, radio resource blocks allocation, and Forward Error Correction (FEC), for multicasting in LTE networks with the assistance of MEC. We formulate it as a convex optimization problem and propose a weighted sub-gradient (WSG) method to find the near-optimal solution. In addition, we also propose a heuristic algorithm based on the concept of Maximizing marginal Gain and Minimizing marginal Loss (MGML). Our simulation results show that both approaches are able to achieve near-optimal solutions and outperform previous work, including MSML [11] and OLM [14] . Our simulation results also show that WSG yields the best QoE fairness index while MGML yields the best system utility in most scenarios.

Background: Healthcare-associated infections (HAIs) cause increases in length of stay, mortality, and healthcare costs. A previous study conducted in Taiwan obtained similar results to those reported in Korea and Japan in 2015. Changes in microorganisms have been noted in recent years. Understanding the recent condition of HAIs in intensive care units (ICUs) can enable healthcare providers to develop effective infection control protocols to reduce HAIs. Methods: We used the Taiwan Nosocomial Infection Surveillance System to evaluate the incidence densities of HAIs, the proportions of causative pathogens, and the proportions of antimicrobial resistance (AMR). The Poisson regression model was constructed to incidence density, and the chi-square test was used to assess proportion. Results: The incidence density of HAIs decreased 5.7 to 5.4 per 1000 person-days. However, the proportions of Klebsiella pneumoniae and Enterococcus faecium significantly increased. In addition, the proportions of carbapenem-resistant K. pneumoniae and vancomycin-resistant Enterococcus faecium significantly increased over time. Conclusion: Analysis of the microorganisms involved in HAIs in ICUs showed elevated proportions of K. pneumoniae and E. faecium with AMR. Infection control protocols have been implemented for several years and require improvements regarding environmental cleanliness and medical staff prevention.

Using molecular beam epitaxy, we prepared seven p-type AlGaN samples of ~25% in Al content, including six samples with Mg-doped/un-doped AlGaN alternating-layer structures of different layer-thickness combinations, for comparing their p-type performances. Lower sheet resistance and higher effective hole mobility are obtained in a layer-structured sample, when compared with the reference sample of uniform Mg doping. The improved p-type performance in a layer-structured sample is attributed to the diffusion of holes generated in an Mg-doped layer into the neighboring un-doped layers, in which hole mobility is significantly higher because of weak ionized impurity scattering. Among the layer-structured samples, that of 6/4 nm in Mg-doped/un-doped thickness results in the lowest sheet resistance (the highest effective hole mobility), which is 4.83 times lower (4.57 times higher) when compared with the sample of uniform doping. The effects of the Mg-doped/un-doped layer structure on p-type performance in AlGaN and GaN are compared.

The present study investigated the influence of two factors, namely, argumentation approach and students’ prior knowledge on the learning of scientific concept and argumentation in descriptive and ...

The purpose of this study was to compare the influence of a single-player game with that of a collaborative game on students' motivation, attention levels, and relaxation levels in a motion-sensing learning environment. Participants were 20 college students in a higher education institution in southern Taiwan. A Kinect-based game with motion-sensing technology was incorporated to help the students enhance their attention levels and reduce their anxiety. Results showed that when the students worked collaboratively, they achieved higher learning motivation. In addition, brainwave data revealed that during the gaming activities, the students' attention levels in both conditions increased. It is suggested that instructors can incorporate collaborative learning environments with a Kinect motion-sensing platform to enhance students' learning motivation.

Argumentation is an important aspect of the scientific education. The purpose of the present studies was to explore the influences of two variables termed "the argumentation strategy" and "the kind of science concept" on student's argumentation in the web-based learning environment. There were two types of argumentation strategies (individual or collaborative) and two kinds of science concepts (descriptive or theoretical) identified for our experimental investigations. The quasi-experimental method was applied in which 138 7th grade students were invited and then assigned into either individual group (N=68) or collaborative group (N=70) randomly. They then participated into a web-based learning pro-gram we developed for six science topics, including three descriptive and three theoretical topics. Several scaffoldings were embedded into the program explicitly and systematically, such as multi-media, a discussion block, and scripts in order to promote students' learning engagement. The students' arguments pro-posed during the web-based learning, including claims, warrants, backings and rebuttals were clarified, coded, and then analyzed. The results showed the argumentation strategy has a significant effect on students' argumentation only in the theoretical topics. The post-hoc analysis showed the students in the collaborative group outperformed their peers significantly in the individual group. In theoretical science topic, the students needed more scaffoldings to acquire an in-depth understanding which supports them to construct multiple types of arguments. Moreover, the students in both groups made significant improvements no matter for the descriptive or the theoretical topics, implying the web-based learning pro-gram was effective for argumentation learning.

The present study investigated the guidance provided by science teachers to resolve conflicts during socioscientific issue-based argumentation activities. A graphical representation (GR) was developed as a tool to code and analyze the dialogue interaction process. Through the GR and qualitative analysis, we identified three types of dialogue reconciling strategies. The first one consists of teacher management, in which the teacher temporarily maintains the right to speak when students get mired in an emotional rebuttal situation. The second strategy involves the use of qualifiers to identify the strengths and weaknesses of an opposing argument. The third strategy consists of providing students with guidance to keep both parties (i.e. the students taking, respectively, the affirmative and negative positions) on the same discussion topic and can be used to assist teachers with forming broad questions that prompt students to conduct deeper discussions. These reconciling strategies were beneficial in ...

This study examines the effects of different simulation interface designs on students' conceptual understanding of optical imaging and mental model development, and clarifies these design implications on students' behavioral performance and average residence time. We developed simulations of two different interfaces—gesture- and mouse-based simulations—to collect and compare data from two respective student groups. We utilized a quasi-experimental design, and selected and assigned 64 sixth-grade students to the gesture-and mouse-based simulation groups. The results showed a significant difference between the mental model tests (MMT) of the two groups. Specifically, among the three aspects of a mental model, answer (phenomenon) and explanations (which explain the phenomenon) showed more significant differences with the use of gesture-based than mouse-based simulations. The multivariate analysis of variance results indicated that students using gesture-based simulations demonstrated a longer average residence time than those using mouse-based simulations. Further, the study results suggest that compared to a traditional mouse-based interface, the application of multi-touch gestures in optical imaging concept learning enabled not only the development of a more complete mental model but also the improvement of students’ science explanation skills.

This study investigated the effects of students’ prior science knowledge and online learning approaches (social and individual) on their learning with regard to three topics: science concepts, inquiry, and argumentation. Two science teachers and 118 students from 4 eighth-grade science classes were invited to participate in this research. Students in each class were divided into three groups according to their level of prior science knowledge; they then took either our social- or individual-based online science learning program. The results show that students in the social online argumentation group performed better in argumentation and online argumentation learning. Qualitative analysis indicated that the students’ social interactions benefited the co-construction of sound arguments and the accurate understanding of science concepts. In constructing arguments, students in the individual online argumentation group were limited to knowledge recall and self-reflection. High prior-knowledge students signific...

The present study investigated the effects of online argumentation scaffolding on students’ argumentation involving hypothetical and theoretical biological concepts. Two types of scaffolding were developed in order to improve student argumentation: continuous scaffolding and withdraw scaffolding. A quasi-experimental design was used with four 8th-grade classes comprising a total of 124 students. Two classes (63 students) were assigned into the continuous scaffolding group, while the other two (61 students) were assigned into the withdraw scaffolding group. All the students participated in online argumentation regarding four units, including two hypothetical concepts and two theoretical concepts. Both online learning process and scientific argumentation assessment results indicated that the continuous scaffolding group performed significantly better in terms of the quality and quantity of argumentation than the withdraw scaffolding group with regard to the hypothetical biology concepts, particularly in generating rebuttal arguments. In addition, the results also showed that both the continuous group and withdraw group students had better argumentation performance with regard to the hypothetical biology concepts than the theoretical biology concepts. Taken together, the study results suggest that learning argumentation through theoretical biology concepts is more difficult than doing so through hypothetical biology concepts.

This study investigated two science teachers’ meta-strategic knowledge (MSK) of argumentation teaching by applying the repertory grid technique (RGT). One teacher was a novice, while the other was experienced in teaching argumentation. Using the RGT, we elicited the objectives and strategies of the two teachers regarding their argumentation teaching involving two social scientific issue (SSI) scenarios. The results showed that the experienced teacher had more varied and organised MSK for teaching argumentation than the novice teacher. Meanwhile, the novice teacher indicated a belief that the learning of argumentation should occur in a more student-centred manner, rather than relying on a traditional lecture-based environment. Consequently, she spent a considerable amount of time engaging students with their peers’ ideas through discussion and collaboration. On the other hand, the experienced teacher noticed that most of students had the ability to generate arguments, but that few knew how to argue based on evidence. Therefore, she helped students to collect data from various resources and suggested that they construct their own knowledge framework in order to improve students’ ability to incorporate their understanding of scientific knowledge into scientific argumentation.

Citrate-capped Au nanoparticles have been assembled onto the surface of LaB 6 nanoparticles with silica coating and amino-functionalization to develop the LaB 6 @SiO 2 /Au composite nanoparticles as a novel catalyst with near-infrared (NIR) photothermally enhanced activity. The basic properties including the morphology, size, structure, zeta potential, and optical property were characterized. They also confirmed the formation of LaB 6 -SiO 2 core–shell structure and the successful assembling of highly dispersed Au nanoparticles on the surface. The resulting LaB 6 @SiO 2 /Au composite nanoparticles were demonstrated to possess the excellent NIR absorption and photothermal conversion properties of LaB 6 cores and the catalytic capability of Au nanoparticles for the reduction of 4-nitrophenol to 4-aminophenol with sodium borohydride. Under NIR irradiation, they photothermally induced the heating of reaction medium and the presence of possible hot spots on the catalyst surface, leading to the enhancement in the reduction rate of 4-nitropeheol. This result will be helpful for the development of photothermally driven catalytic systems.

This paper presents a converter design for fuel cell operations enhanced with a cooperation of supercapacitors and lithium batteries. The study is motivated because the properties of connected sources of fuel cell, lithium battery and super-capacitor are mutually different. An integrated converter with the energy control to regulate the power flow hence becomes crucially important. In the study, through the utilization of an improved step-down circuit along with the isolated circuit design, the completed converter is proved effective to supply power from fuel cells along with a backup support of supercapacitors and lithium batteries. By validating this proposed circuit under different load scenarios, test results help confirm the practical values of this design for green energy applications.

This study investigated the pathways involved in the effect of green tea epigallocatechin gallate (EGCG) on mitogenesis in BeWo, JEG-3, and JAR placental choriocarcinoma cells. EGCG inhibited cell proliferation in dose-dependent and time-dependent manners, as indicated by the number of cells and incorporation of bromodeoxyuridine (BrdU). A catechin-specific effect of green tea was evident; EGCG was more effective than epicatechin, epicatechin gallate, and epigallocatechin in suppressing cell growth. When all three of the mitogen-activated protein kinase (MAPK) subfamilies, i.e., ERK, p38, and JNK, were examined, EGCG significantly increased levels of phospho-ERK1/2 (pERK1/2) and phospho-p38 (pp38) and did not alter the total protein levels of ERK1/2, p38 MAPK, JNK, and phospho-JNK. EGCG-induced increases in the levels of pERK1/2 and pp38 proteins were prevented by pre-treatment with specific inhibitors of ERK1/2 MAPK and p38 MAPK, respectively. These inhibitors also suppressed EGCG-induced decreases in both cell number and BrdU incorporation. Moreover, pre-treatment with an AMP-activated protein kinase (AMPK) inhibitor prevented the actions of EGCG on proliferation and AMPK phosphorylation. These data suggest that EGCG mediates choriocarcinoma cell growth via the AMPK, ERK, and p38 pathways, but not JNK pathway.

Sn/Ni–8.0 at.%V (Ni–7.0 wt%V) couples are prepared and the interfacial reactions at 210 and 250 °C are examined. In the early stage of reaction at 250 °C, a T phase is formed as a result of fast diffusion of Sn into the Ni–8.0 at.%V substrate. With a longer reaction, the outer region of the T phase transforms to a Ni-depletion layer, which has not been observed previously. Both the T phase and the Ni-depletion layer are analyzed using transmission electronic microscopy. This newly found Ni-depletion layer is composed of Sn and nanosize “VSn2(V2Sn3)” particulates. The solid/solid reaction paths in the Sn/Ni–8.0 at.%V couples evolve from Sn/T/Ni–V, Sn/Ni3Sn4/T/Ni–V to Sn/Ni3Sn4/VSn2(V2Sn3). During the liquid/solid reactions, the paths are liquid/T/Ni–V, liquid/liquid + Ni3Sn4/T/Ni–V, liquid/liquid + Ni3Sn4/liquid + VSn2(V2Sn3)/T/Ni–V, and liquid/liquid + Ni3Sn4/liquid + VSn2(V2Sn3).

The Ni-8.0 at.%V (Ni-7.0 wt.%V) substrate is an important diffusion barrier layer material in flip-chip technology. This study examines interfacial reactions in couples prepared using Ni-8.0 at.%V substrate and Sn-6.0 at.%Pb, Sn-27.6 at.%Pb, and Sn-83.8 at.%Pb solders, at temperatures between 210°C and 450°C. In the Sn-27.6 at.%Pb/Ni-8.0 at.%V and Sn-83.8 at.%Pb/Ni-8.0 at.%V couples, the reaction products are the Ni3Sn4 phase and a T phase with limited Pb solubility, being similar to those in the Sn/Ni-8.0 at.%V couples. However, the Ni3Sn4 phase is formed at an earlier stage and the T phase is formed later. The phase formation sequences are different from those in Sn/Ni-8.0 at.%V couples. In Sn-6.0 at.%Pb/Ni-8.0 at.%V couples, a “Pb-rich” phase is formed, in addition to the T phase and the Ni3Sn4 phase, and the T phase and Ni3Sn4 phase are formed almost simultaneously. Although Pb does not participate actively in the interfacial reactions, the phase formation sequences are changed when Pb alloys in the solder, due to the reduced Sn flux from the solder into the Ni-8.0 at.%V substrate.

There is considerable disagreement among researchers about chemistry learning approach. Some have been said to demonstrate an individual advantage, some a social advantage. While there is a great deal of general literature on this field, however, the specific web-based conductive learning is relatively unexplored. We proposed a Chemistry Online Argumentation Courseware (COAC) for enhancing 10th grade students' learning with website exploring conductive components where senior high school students can easily navigate the embedded website links and create effective scientific arguments. The purpose of this paper is to report on an investigation of learners' online argumentation activity. Answers were sought to the question: how does the website exploring strategy influence students' argumentation performance on our conductive COAC. Qualitative results suggested that both Individual and Social group learners had significant improvements in their argumentation ability with the support of website exploring. This study further suggested that the benefit of website exploring argumentation-strategies instruction to the Individual group learners in the chemistry course, they improved fast enough to attain the same progress as the collaborative learners regarding argumentation-based learning. The findings of this study could serve as some general principles for teachers who would like to improve students' website learning strategy use.

The present study explored the effects of students' prior knowledge of science and online collaborative approaches on their science argumentation learning. Two science teachers and 102 students from four 8th grade science classes were invited to in our study. Students in each class were divided into three groups according to their prior knowledge level on science, they then took either our collaborative - or individual-based online learning program. The results show that high prior-knowledge students significantly outperformed low prior-knowledge students in argumentation. Moreover, students in the collaborative argumentation group performed better than their peers in individual group. This implies that if science teachers create a more collaborative learning environments, it would promote students' communication among peers and facilitate their argumentation learning.

Intelligent Vehicle Safety imaging system using image processing often requires a lot of internal memory register or DDR SDRAM (Double-Data-Rate Synchronous Dynamic Random Access Memory) to temporary video and images. But these processes often increases the complexity of the hardware and software. In this system, we propose a VLSI implementation of image-based lane departure warning system. It is not only the gradient calculation of the lines and discrimination out of the lane line, but also real-time analysis of vehicle tires with the left and right side of the lane markings distance through the image of the video, and then judge whether the car lane offsets phenomenon. This system has been implemented in the Xilinx Spartan6 FPGA platform. It is using total 32% of logic resources, and it doesn't use SRAM or SDRAM. Its average recognition rate is 95%, the image frame rate 30 frames / s, and proceed forthwith back-end design with logic synthesis and Auto Place & Rout (APR) processing. This chip uses 0.18 um standard cell process. This system's core area is 1.47 * 1.47 mm2, and core utilization is 0.8, sequential cell occupy 40% and frequency up to 100 MHz. This chip has advantages of low cost, small size and low power more than DSP or FPGA. It will be also more suitable to use in vehicle applications system, without external memory.

Using vision based solution in intelligent vehicle application often needs large memory to handle video stream and image process which increase complexity of hardware and software. In this paper, we present a FPGA implement of a vision based lane departure warning system. By taking frame of videos, the line gradient of line is estimated and the lane marks are found. By analysis the position of lane mark, departure of vehicle will be detected in time. This idea has been implemented in Xilinx Spartan6 FPGA. The lane departure warning system used 39% logic resources and no memory of the device. The average availability is 92.5%. The frame rate is more than 30 frames per second (fps).

Sn is the base element of all the promising electronic solders, and Ni-7wt.%V is the major diffusion barrier layer material of flip chip technology. Interfacial reactions in the Sn/Ni-7wt.%V couple at 250°C are examined in this study. The Ni 3 Sn 4 phase is observed in the Sn matrix. Two phase layers, Sn-Ni-V ternary phase (T phase) and a mixture of the nano-crystalline V 2 Sn 3 phase and Sn phase (T2 phase), are observed at the Sn/Ni-7wt.%V interface. The micro structures of T phase and T2 phase was analyzed by TEM, T phase has a dense structure and T2 phase has a loose structure. The loose structure of Sn-V phase can not only cause a harmful effect on mechanical properties, but also on electrical properties.