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81.
Techniques for enforcing the continuity of solute field in heterogeneous solvent under the conditions of steady temperature-humidity, steady temperature but dynamic humidity, and dynamic temperature are reviewed. The continuity of the wetness technique is justified on the principle of equality of chemical potential. The partial pressure technique is one of the many possible forms of pseudo techniques that can be derived from the wetness technique. The direct concentration technique is fundamentally flaw. The peridynamic technique in its original form is restricted to homogeneous solvent. The saturated concentration of solute in solvents decreases with increasing temperature; the rate of change with temperature differs between solvents and this leads to discontinuity of wetness along the interface of solvents. Continuity of wetness at the interface may be enforced using the intervention technique, the internal source technique, or the explicit finite difference scheme. These three techniques have been mutually validated in a reported study. 相似文献
82.
This paper presents an experimental investigation on the microwave performance of a GaN HEMT subject to UV light exposure. The device, having 0.25 μm gate length and 100 μm gate width, has been characterized by measuring its DC performance, linear scattering parameters, noise parameters in the 2–26 GHz frequency range, either in dark condition and under CW light exposure at 375 nm. Clear variations of the GaN HEMT performance related to the charge generation and the relevant threshold voltage shift within the semiconductor layers are recognizable in the reported results. The scattering parameters and the noise parameters are affected in a similar way as it occurs in GaAs HEMT's under optical irradiation in the visible range. A circuit model extraction has then been performed to analyze more deeply the effects of the UV exposure. The observed changes of the noise parameters might be ascribed to the effects of the increased gate conduction under illumination and have been efficiently modeled by an additional resistor between the internal gate and source terminals with an assigned noise temperature of 3053 °C. 相似文献
83.
Studies on Game Transfer Phenomena (GTP) have demonstrated that experiencing altered sensorial perceptions, automatic thoughts and behaviours after playing video games are relatively common phenomena. The aim of this paper is twofold: (i) to validate the Turkish version of the GTP scale (GTPS), and (ii) to examine the prevalence and the relation between the various dimensions of GTP (e.g., visual perceptions, thoughts, behaviours) and video game players’ individual characteristics (e.g., demographics, gaming habits). A total of 954 frequent players were recruited online. Independently of the different samples used in the original validation of the GTPS and the current study, the findings obtained via confirmatory factor analysis showed that the GTPS-Turkish is reliable and valid and proved to be adequate for measuring GTP. A total of 99% of the players in the sample had experienced some type of GTP. Moreover, the correlational, univariate and multivariate analyses showed associations between various video game player characteristics and GTP. The most remarkable finding was that the prevalence of GTP was higher among minors than adults. 相似文献
84.
Tero Luukkonen Emma-Tuulia Tolonen Hanna Runtti Kimmo Kemppainen Paavo Perämäki Jaakko Rämö Ulla Lassi 《Journal of Materials Science》2017,52(16):9363-9376
Geopolymers are functional materials that can be used in various environmental applications such as adsorbents in pollutant removal from wastewaters. Metakaolin geopolymer (MK-GP) has been proven to be especially suitable for ammonium (NH4 +) removal. In this research, the optimal reagent and raw material ratios in the preparation of MK-GP in terms of NH4 + adsorption capacity were investigated. The response surface methodology based on the face-centered central composite design was used to optimize the levels of three factors: the amounts of hydroxide, silicate, and metakaolin. In addition, the effect of Na or K as the charge-balancing cation was studied. Empirical models were fitted to the experimental data using multiple linear regression. The significance of the models was confirmed by means of analysis of variance. Optimal NH4 + removal efficiency was achieved when the amounts of hydroxide and silicate were maximized, the amount of metakaolin was minimized, and Na-based reagents were used. These trends are most likely a result of optimized conversion of metakaolin into MK-GP. 相似文献
85.
The number of scholarly publications on agile software development has grown significantly in recent years. Several researchers reviewed and attempted to synthesize studies on agile software development. However, no work has ranked the contributions of scholars and institutions to publications using a thorough process. This study presents findings on top publications, institutions, and scholars in the agile software development field from 2001 to 2012 based on the publication of such works in Science Citation Index journals. This paper highlights the key outlets for agile research and summarizes the most influential researchers and institutions as well as the most studied research areas. This study concludes by providing directions for future research. 相似文献
86.
Song Fu Osmo Kauppila Matti Mottonen 《The International Journal of Advanced Manufacturing Technology》2011,57(9-12):1079-1086
In 100% inspection, measurement errors are unavoidable. Due to these errors, acceptable products are sometimes rejected (overkill) and defective products are accepted (escape). Overkill increases production costs, while escape is a source of customer dissatisfaction. This study presents a model for calculating overkill and escape rates using process and measurement system performance data. A practical example of applying the model is also presented to calculate gage reproducibility and repeatability requirements for different production settings. Industrial managers and quality engineers can utilize the results of this study to calculate escape and overkill rates of their production systems, and to assess and improve their processes. 相似文献
87.
《Journal of the European Ceramic Society》2022,42(9):3913-3919
Artificially tilted multilayer thermoelectric devices (ATMTDs) have attracted growing attention due to their ease in miniaturization and high flexibility in device design. However, most of these devices are inefficient due to the lack of effective strategy to optimize their material matching and geometrical configurations. Herein, a high-throughput optimization approach is employed to screen high-performance Bi2Te2.7Se0.3-based ATMTDs from a material genome database covering 230 kinds of candidates. 14 kinds of ATMTDs are found to have ZTzx,max values exceeding 0.3 and tilt angles greater than 15°. Bi0.1Sb1.9Te3/Bi2Te2.7Se0.3 ATMTD is screened out and fabricated because of its excellent transverse figure of merit, large tilt angle, and good interface compatibility. Consequently, transverse figure of merit over 0.3, thermal sensitivity greater than 0.11 mV·K?1, and power density up to 1.1 kW·m?2 are recorded in Bi0.1Sb1.9Te3/Bi2Te2.7Se0.3 ATMTD. This indicates that ATMTDs have great potential for application in the fields of temperature detection and power generation. 相似文献
88.
《Journal of the European Ceramic Society》2022,42(1):154-161
A series of high-k Ba4Nd28/3Ti18-yGa4y/3O54 (0≤y≤2, BNTG) ceramics with temperature stable and ultra-low dielectric loss were synthesized via the conventional solid-state reaction. The main phase of all BNTG ceramics demonstrated an orthorhombic tungsten-bronze structure, but the impurity phase (gallium-rich phase) was found in BNTG (y = 2) ceramic. Partial substitution of Ga3+ for Ti4+ in B-site was a valid method to improve the temperature stability and dielectric loss of BNTG ceramics. The variation of εr values of BNTG ceramics was dominated by the ionic polarizability. The ultra-low dielectric loss (ultra-high Q × f values) was associated with grain size, suppression of Ti3+ and impurity phase. The decrease of TCF values was highly dependent on the tilting of Ti-O octahedra and impurity phase. Finally, outstanding combination dielectric characteristics were achieved for BNTG microwave ceramics at y = 1.5 (εr = 72.8, Q × f = 14,600 GHz, TCF=+4.1 ppm/°C) and at y = 2 (εr = 70.3, Q × f = 15,500 GHz, TCF=+3.9 ppm/°C). 相似文献
89.
《Journal of the European Ceramic Society》2022,42(2):448-452
This study used a traditional solid-state reaction method to prepare a series of composite ceramics in the 0.7Mg4Nb2O9-(0.3-x)ZnAl2O4-xTiO2 ternary system. Crystalline phases and microstructure of Mg4Nb2O9-ZnAl2O4-TiO2 dielectric ceramic composites were investigated and correlated with the relevant dielectric properties. It was observed that the addition of Ti4+ substituted Nb5+ in the Mg4Nb2O9 structure, which promoted the decomposition of Mg4Nb2O9 to form the second phase, Mg5Nb4O15, during sintering. The synergistic effect of ZnAl2O4-TiO2 co-doping promoted the Mg4Nb2O9 ceramic densification. The sample (0.7Mg4Nb2O9-(0.3-x)ZnAl2O4-xTiO2) with x = 0.15?0.2 exhibited dielectric constants of 13–14, larger than those of ZnAl2O4, Mg4Nb2O9 and Mg5Nb4O15, due to the NbO6 octahedra distortion resulting from the substitution of Al3+/Ti4+ for Nb5+ in Mg4Nb2O9 and Mg5Nb4O15. The long-range order of the NbO6 octahedra was enhanced by co-doping ZnAl2O4 and TiO2, thereby enhancing the Qxf value. A dielectric constant of 13.1, Qxf value of 366,000 GHz and a τf of ?60.8 ppm/°C were obtained from 1300 °C sintered 0.7Mg4Nb2O9-0.15ZnAl2O4-0.15TiO2. These results show that 0.7Mg4Nb2O9-0.15 ZnAl2O4-0.15TiO2 ceramic is a good candidate for microwave electronic device applications. 相似文献