1,393 research outputs found

    Efficient Volumetric Method of Moments for Modeling Plasmonic Thin-Film Solar Cells with Periodic Structures

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    Metallic nanoparticles (NPs) support localized surface plasmon resonances (LSPRs), which enable to concentrate sunlight at the active layer of solar cells. However, full-wave modeling of the plasmonic solar cells faces great challenges in terms of huge computational workload and bad matrix condition. It is tremendously difficult to accurately and efficiently simulate near-field multiple scattering effects from plasmonic NPs embedded into solar cells. In this work, a preconditioned volume integral equation (VIE) is proposed to model plasmonic organic solar cells (OSCs). The diagonal block preconditioner is applied to different material domains of the device structure. As a result, better convergence and higher computing efficiency are achieved. Moreover, the calculation is further accelerated by two-dimensional periodic Green's functions. Using the proposed method, the dependences of optical absorption on the wavelengths and incident angles are investigated. Angular responses of the plasmonic OSCs show the super-Lambertian absorption on the plasmon resonance but near-Lambertian absorption off the plasmon resonance. The volumetric method of moments and explored physical understanding are of great help to investigate the optical responses of OSCs.Comment: 11 pages, 6 figure

    The Value Orientation of Entrepreneurial University Curriculum Design

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    According to the essential characteristics and personnel training characteristics of entrepreneurial university, in accordance with the characteristics and objectives of curriculum, and combined with the latest theoretical research of entrepreneurship curriculums at home and abroad, this essay adopts literature data and logic analysis method to explore entrepreneurial universities on the real value of curriculum design. The results are that entrepreneurial universities in the curriculum design mainly treated social standard as the main, ignored the value of the individual, in addition, curriculums’ goal is single, as well as rigid in terms of creative personnel training. We should establish a wide range of educational values in Entrepreneurial universities’ curriculum reform: realizing effective integration between educational localization and educational internationalization; taking into account the main educational values; achieving an effective balance between scientific world and the world of life; focusing on the development of personality and building the harmonious development of human beings

    Preparation and Numerical Modelling of Ceramic Foam Insulation for Energy Saving in Buildings

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    For the purpose of energy saving in buildings, a foam ceramic insulation (FCI) was prepared by using fly ash (FA) and ceramic waste (CW) as the main raw materials for its matrix part and foam part, respectively. The effects of the sintering temperature and the additive agent on the macroscopic performances were systematically measured and investigated. The experiment results indicate that for the matrix sample 5% quartz addition makes the rupture modulus at 1200°C reach high to 34.28 MPa, while the corresponding water absorption capacity is only 0.83%. In addition, for the foam sample with 1 wt% silicon carbide, the lowest measured bulk density and thermal conductivity at 1200°C are 0.471 g/cm3 and 0.1184 W/(m•K), respectively. Furthermore, the proposed simulation model predicts that the effective thermal conductivity of FCI decreases with the decrease of the bulk density. Moreover, the simulation results calculated by EnergyPlus software indicate that the synthetic FCI can efficiently reduce the building’s heating and cooling loads and exerts excellent energy conservation effect

    Finding False Assurance in Formal Verification of Software Systems

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    Formal verification plays a crucial role in enhancing the reliability of computing systems by mathematically checking the correctness of a program. Although recent years have witnessed lots of research and applications that optimize the formal verification process, the issue of false assurance persists in certain stages of the formal verification pipeline. The false assurance problem is critical as it can easily undermine months if not years of verification efforts. In this thesis, we first generalized the formal verification process. We then identified and analyzed specific stages susceptible to false assurance. Subsequently, a systematization of knowledge pertaining to the false assurance issues observed at these stages is provided, accompanied by a discussion on the existing defense mechanisms that are currently available. Specifically, we focused on the problem of formal specification incompleteness. We presented FAST in this thesis, which is short for underlineFuzzing-underlineAssisted underlineSpecification underlineTesting. FAST examines the spec for incompleteness issues in an automated way: it first locates spec gaps via mutation testing, i.e., by checking whether a code variant conforms to the original spec. If so, FAST further leverages the test suites to infer whether the gap is introduced by intention or by mistake. Depending on the codebase size, FAST may choose to generate code variants in either an enumerative or evolutionary way. FAST is applied to two open-source codebases that feature formal verification and helps to confirm 13 and 21 blind spots in their spec respectively. This highlights the prevalence of spec incompleteness in real-world applications

    Slip distribution and tectonic implication of the 1999 Chi‐Chi, Taiwan, Earthquake

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    We report on the fault complexity of the large (M_w = 7.6) Chi‐Chi earthquake obtained by inverting densely and well‐distributed static measurements consisting of 119 GPS and 23 doubly integrated strong motion records. We show that the slip of the Chi-Chi earthquake was concentrated on the surface of a ”wedge shaped” block. The inferred geometric complexity explains the difference between the strike of the fault plane determined by long period seismic data and surface break observations. When combined with other geophysical and geological observations, the result provides a unique snapshot of tectonic deformation taking place in the form of very large (>10m) displacements of a massive wedge‐shaped crustal block which may relate to the changeover from over‐thrusting to subducting motion between the Philippine Sea and the Eurasian plates

    Premedication with dexmedetomidine in pediatric patients: a systematic review and meta-analysis

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    Premedication is important in pediatric anesthesia. This meta-analysis aimed to investigate the role of dexmedetomidine as a premedicant for pediatric patients. A systematic literature search was conducted to identify randomized controlled trials comparing dexmedetomidine premedication with midazolam or ketamine premedication or placebo in children. Two reviewers independently performed the study selection, quality assessment and data extraction. The original data were pooled for the meta-analysis with Review Manager 5. The main parameters investigated included satisfactory separation from parents, satisfactory mask induction, postoperative rescue analgesia, emergence agitation and postoperative nausea and vomiting. Thirteen randomized controlled trials involving 1190 patients were included. When compared with midazolam, premedication with dexmedetomidine resulted in an increase in satisfactory separation from parents (RD = 0.18, 95% CI: 0.06 to 0.30, p = 0.003) and a decrease in the use of postoperative rescue analgesia (RD = -0.19, 95% CI: -0.29 to -0.09, p = 0.0003). Children treated with dexmedetomidine had a lower heart rate before induction. The incidence of satisfactory mask induction, emergence agitation and PONV did not differ between the groups. Dexmedetomidine was superior in providing satisfactory intravenous cannulation compared to placebo. This meta-analysis suggests that dexmedetomidine is superior to midazolam premedication because it resulted in enhanced preoperative sedation and decreased postoperative pain. Additional studies are needed to evaluate the dosing schemes and long-term outcomes of dexmedetomidine premedication in pediatric anesthesia
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