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981.
Forecasting is one of the crucial factors in applications because it ensures the effective allocation of capacity and proper amount of inventory. Because Box–Jenkins models using linear forecasting have their constraint to predict complexity in the real world, other nonlinear approaches are developed to conquer the challenge of nonlinear forecasting. With the same goal, we are proposing a hybrid of genetic algorithm and artificial immune system (HGAI) algorithm with radial basis function neural network learning for function approximation and further applying it to conduct an industrial personal computer sales forecasting exercise. In addition, five well‐known benchmark problems were used to evaluate the results in the experiment, and the newly proposed HGAI algorithm has returned better results than the Box–Jenkins models and other algorithms.  相似文献   
982.
Tungsten ditelluride (WTe2) is a semimetal with orthorhombic Td phase that possesses some unique properties such as Weyl semimetal states, pressure‐induced superconductivity, and giant magnetoresistance. Here, the high‐pressure properties of WTe2 single crystals are investigated by Raman microspectroscopy and ab initio calculations. WTe2 shows strong plane‐parallel/plane‐vertical vibrational anisotropy, stemming from its intrinsic Raman tensor. Under pressure, the Raman peaks at ≈120 cm?1 exhibit redshift, indicating structural instability of the orthorhombic Td phase. WTe2 undergoes a phase transition to a monoclinic T′ phase at 8 GPa, where the Weyl states vanish in the new T′ phase due to the presence of inversion symmetry. Such Td to T′ phase transition provides a feasible method to achieve Weyl state switching in a single material without doping. The new T′ phase also coincides with the appearance of superconductivity reported in the literature.  相似文献   
983.
B2O3/SiO2 substitution in 55S4.3 bioactive glasses with 5 mol% of SrO has been synthesized and characterized to understand their structure and bioactivity as a function of composition by combining experimental and computer simulation techniques. Raman spectrometry, X-ray diffraction (XRD) and Fourier transform infrared spectrometry (FTIR) were utilized to characterize the structural changes induced by boron content and to identify the formation of hydroxyapatite (HAp). In vitro bioactivity tests were performed in simulated body fluid with a fixed glass mass to solution volume ratio and a particle size range. Needle-like HAp was found to form on the surface of the 55S4.3 with SrO sample from scanning electron microscopy and confirmed from XRD and FTIR. In addition to the experimental efforts, these glasses were also simulated using classical molecular dynamics simulations with partial charge potentials and recently developed parameters for boron oxide to understand their short- and medium-range structures. The glasses from simulations were analyzed in terms of the local structure around the glass network formers, especially the boron coordination number, and found to agree well with theoretical models. The medium-range structural information such as Q n distribution and network connectivity was also obtained and used to understand the compositional dependence of property and bioactivity. The results show that additional boron oxide increased the network connectivity of the 55S4.3 glass and inhibited or delayed the formation of HAp in vitro.  相似文献   
984.
Hard corona (HC) protein, i.e., the environmental proteins of the biological medium that are bound to a nanosurface, is known to affect the biological fate of a nanomedicine. Due to the size, curvature, and specific surface area (SSA) 3‐factor interactions inherited in the traditional 3D nanoparticle, HC‐dependent bio–nano interactions are often poorly probed and interpreted. Here, the first HC‐by‐design case study in 2D is demonstrated that sequentially and linearly changes the HC quantity using functionalized graphene oxide (GO) nanosheets. The HC quantity and HC quality are analyzed using NanoDrop and label‐free liquid chromatography–mass spectrometry (LC‐MS) followed by principal component analysis (PCA). Cellular responses (uptake and cytotoxicity in J774 cell model) are compared using imaging cytometry and the modified lactate dehydrogenase assays, respectively. Cellular uptake linearly and solely correlates with HC quantity (R2 = 0.99634). The nanotoxicity, analyzed by retrospective design of experiment (DoE), is found to be dependent on the nanomaterial uptake (primary), HC composition (secondary), and nanomaterial exposure dose (tertiary). This unique 2D design eliminates the size–curvature–SSA multifactor interactions and can serve as a reliable screening platform to uncover HC‐dependent bio–nano interactions to enable the next‐generation quality‐by‐design (QbD) nanomedicines for better clinical translation.  相似文献   
985.
986.
We have measured Seebeck coefficient (S) of FeTe0.5Se0.5 superconducting sample from 10 to 300 K. The variation of Seebeck coefficient with temperature of this system was found to be very anomalous, and the overall experimental observation of the S(T) was studied in the outline of a narrow-band model. In high-temperature region, the Seebeck coefficient is almost independent of temperature. Further, from the study of high-temperature magnitude of S, sample undergoes a change in sign in the Seebeck coefficient, wherein, appearance of a negative peak around 22 K and subsequently, its Seebeck coefficient goes to zero in the superconducting transition temperature regime around 11 to 13 K. It is revealed that the bandwidth and a small asymmetry involved in narrow bands give a realistic explanation to the anomalous temperature dependence of Seebeck coefficient of FeTe0.5Se0.5 system.  相似文献   
987.
Traditional post-level opinion classification methods usually fail to capture a person’s overall sentiment orientation toward a topic from his/her microblog posts published for a variety of themes related to that topic. One reason for this is that the sentiments connoted in the textual expressions of microblog posts are often obscure. Moreover, a person’s opinions are often influenced by his/her social network. This study therefore proposes a new method based on integrated information of microblog users’ social interactions and textual opinions to infer the sentiment orientation of a user or the whole group regarding a hot topic. A Social Opinion Graph (SOG) is first constructed as the data model for sentiment analysis of a group of microblog users who share opinions on a topic. This represents their social interactions and opinions. The training phase then uses the SOGs of training sets to construct Sentiment Guiding Matrix (SGM), representing the knowledge about the correlation between users’ sentiments, Textual Sentiment Classifier (TSC), and emotion homophily coefficients of the influence of various types of social interaction on users’ mutual sentiments. All of these support a high-performance social sentiment analysis procedure based on the relaxation labeling scheme. The experimental results show that the proposed method has better sentiment classification accuracy than the textual classification and other integrated classification methods. In addition, IMSA can reduce pre-annotation overheads and the influence from sampling deviation.  相似文献   
988.
Radio resource management to enable user association and resource block (RB) allocation is crucial for enhancing the performance of heterogeneous networks (HetNets), which are required for fifth generation (5G) mobile networks. This paper proposed a resource allocation technique based on a genetic algorithm (GA) for use in HetNets. We aimed to optimize user association and RB allocation simultaneously to fulfill multiple objectives, such as throughput and fairness measure. In addition to the four primary phases used in GA process, namely initialization, crossover, mutation, and selection, a further operator was provided for managing illegal offspring generated during a GA process. We performed a simulation to compare the proposed GA‐based approach with best channel quality indicator (CQI) algorithm and integer linear programming (ILP) approach in terms of total throughput and fairness measure. The simulation results revealed that the total throughput obtained using the proposed approach is 32.7% and 37.6% better than that obtained using the ILP and best CQI approaches, respectively. Moreover, the fairness measure obtained using the proposed GA‐based approach was 31.8% and 33.2% higher than that obtained using ILP and best CQI approaches, respectively.  相似文献   
989.
The opal photonic crystals (PCs) were assembled by vertical deposition of polystyrene microspheres (PS), in which Yb3+, Er3+ co-doped ZnO powders were deposited on the surface of PC films. The phase, structure and morphology of the obtained samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscope (TEM). The performance of up-conversion photoluminescence (UCPL) was investigated by fluorescence spectrophotometer. The up-conversion (UC) emission of ZnO:Yb3+/Er3+on the PC surface is notably enhanced when the UC emission wavelength is overlapped with the photonic bandgaps of opals, which is attributed to Bragg reflection of photonic bandgap. The results show that PCs may have potential applications in the enhancement of UCPL and optoelectronic devices.  相似文献   
990.
International Journal of Control, Automation and Systems - Dissimilar redundant actuation systems (DRAS) are in practice in advanced aircraft in order to increase reliability and to resolve the...  相似文献   
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