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Research universities can be more than centers of research and education; in the best cases, they can also be hotbeds of innovation and entrepreneurship. We have examined successful innovators and noted similarities and differences. This article describes results from a preliminary investigation that supports a vibrant innovation ecosystem in the fields of materials, energy, and environment at Stanford University. The results are drawn from interviews of a small number of successful innovators in these fields. All of the interview subjects were similar in that they operated within a gap between the present state of the art and a vision of how a particular innovation could reshape the world around them. Important differences were also observed. We found that successful models can be grouped into three successful classes of inquiry: basic research, the search for new solutions to well-known problems, and exploiting the evolutionary arc of technology. Each class of inquiry appears to be matched to definite approaches, and we believe that distinct factors can be used to drive cultural change and enhance the effectiveness of researchers and organizations. Future research in this area may carefully examine these factors and the broader applicability of these findings to other innovation contexts.
The integration of synchrotron and high-pressure techniques has significantly advanced research in materials science, giving rise to many important discoveries in physics, chemistry, environmental science, and many other fields of physical and engineering sciences. The relevant frontier work in multiple disciplines is reviewed. The selected studies include high-pressure superconductivity, lattice dynamics of materials, plastic deformation of nanomaterials, polyamorphic transitions and devitrification in metallic glass, rheology of minerals, and high-pressure chemistry probing.
In this study, the ternary Ge–Sb–Se chalcogenide glass was fabricated by a standard melt-quenching technique for flexible infrared lenses. Chalcogenide glass should have unique thermal and mechanical properties to be applied to precision glass molding (PGM) process. Therefore, the relations between thermal properties and the moldability were investigated for (35–20)Ge–(5–20)Sb–60Se glass systems. The thermal and thermos-mechanical properties were characterized by the differential scanning calorimeter and thermos-mechanical analysis, respectively. Preceding experiments using a pressing tester were conducted before PGM process to evaluate the moldability. The surface condition of both chalcogenide glass disks and Tungsten Carbide (WC) molds were characterized by using an optical microscopy and an interferometer. The preferential compositions in (35–20)Ge–(5–20)Sb–60Se glass systems were selected to produce molded lenses. Finally, the molded chalcogenide lens was successfully fabricated using the preferential compositions and the processing conditions from the preceding experiments using a pressing tester.
To study the hot deformation behavior of the Ti–22Al–25Nb alloy, isothermal compression tests were conducted at the temperature range of 930–1080 °C with strain rates of 0.001–1.0 s−1. Both the strain rate and the deformation temperature have a significant influence on the stress–strain behavior of the Ti–22Al–25Nb alloy. A hyperbolic–sine constitutive equation is established to quantitatively demonstrate the relationship between the parameters involved, and the hot deformation activation energy Q is determined as 621 kJ/mol. To optimize the processing window, a hot processing map is established, which is related to the microstructure evolution in hot working. The lamellar globularization as well as the dynamic recrystallization (DRX) would contribute to the stable regions with high power dissipation, while the adiabatic shear bands would lead to unstable regions. Moreover, an Avrami-type kinetics model is applied to examine the evolution of DRX during isothermal deformation process.
With the advent of flexible, wearable and portable electronic products, flexible lithium-ion batteries (LIBs) and electrochemical capacitors (ECs), which are able to withstand repeated deformation or bending, have attracted considerable attention as one type of energy-storage device. However, the fabrication of these flexible electrodes is the main bottleneck in the practical utilization and application of these energy-storage devices. Up to now, enormous efforts have been made in addressing the shortcomings and remarkable improvements have also been achieved. So a systematic review of the status and progresses is highly required. In this review, we first make a short introduction about the challenges faced in the conventional batteries and capacitors. Then, we summarize the recent improvements in flexible and wearable LIBs and ECs with a focus on the flexible active materials and substrates. Finally, we discuss the prospects and challenges towards the practical applications of the flexible electrodes in the future.
Red-emitting (La,Eu)2O2SO4 phosphors have been successfully prepared using the layered hydroxide of (La,Eu)2(OH)4SO4·2H2O as the precursor. The precursor compound was firstly crystallized via hydrothermal reaction (100 °C and pH = 9.0) as well-dispersed nanoplates, followed by dehydration and dehydroxylation in the 400–1200 °C temperature range in ambient air to yield (La,Eu)2O2SO4. The phosphors show intense red emissions originated from the f–f transitions of Eu3+, dominantly peaking at 617 nm, under O–Eu charge transfer excitation at 284 nm. The optimal Eu3+ content was experimentally determined to be 5 at.%, agreeing well with theoretical analysis, and the concentration quenching of luminescence was suggested to be due to exchange interactions. Fluorescence decay analysis indicates that a higher calcination temperature or Eu3+ content would decrease the lifetime of the 617 nm emission.
Thermoluminescence (TL) and radioluminescence (RL) spectra of the long-lasting phosphorescence of SrA12O4:Eu2+,Dy3+ with A1N addition and commercially used SrA12O4:Eu2+,Dy3+ were compared. Their spectra were slowly recorded over the temperature range from 25 to 673 K (400 °C). A1N offers a higher temperature TL peak, which should lengthen the phosphor lifetime. However, both TL and RL, especially that below room temperature, reveal that there are additional decay paths for the samples of SrA12O4:Eu2+,Dy3+ with A1N additions. These new defect sites reduce the phosphor efficiency. Some speculative models of potential sites are proposed and discussed. In addition, discontinuous intensity changes have been observed for both sample types in TL and RL spectra, which are assigned to the transitions of embedded impurity phases. The justification for this model is explained. Suggestions for future experimentation are also considered.