Browsing by Author "Zhang, J."
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Item High-Performance Biscrolled MXene/Carbon Nanotube Yarn Supercapacitors(Wiley-VCH Verlag) Wang, Z.; Qin, S.; Seyedin, S.; Zhang, J.; Wang, J.; Levitt, A.; Li, Na; Haines, Carter; Ovalle-Robles, R.; Lei, W.; Gogotsi, Y.; Baughman, Ray H.; Razal, J. M.; 0000 0003 5232 4253 (Baughman, RH); 0000-0001-5845-5137 (Baughman, RH); Li, Na; Haines, Carter; Baughman, Ray H.Yarn-shaped supercapacitors (YSCs) once integrated into fabrics provide promising energy storage solutions to the increasing demand of wearable and portable electronics. In such device format, however, it is a challenge to achieve outstanding electrochemical performance without compromising flexibility. Here, MXene-based YSCs that exhibit both flexibility and superior energy storage performance by employing a biscrolling approach to create flexible yarns from highly delaminated and pseudocapacitive MXene sheets that are trapped within helical yarn corridors are reported. With specific capacitance and energy and power densities values exceeding those reported for any YSCs, this work illustrates that biscrolled MXene yarns can potentially provide the conformal energy solution for powering electronics beyond just the form factor of flexible YSCs.Item Observation of Floquet Bands in Driven Spin-Orbit-Coupled Fermi Gases(American Physical Society) Huang, L.; Peng, P.; Li, D.; Meng, Z.; Chen, L.; Qu, Chunlei; Wang, P.; Zhang, Chuanwei; Zhang, J.; 4042455 (Zhang, C); Qu, Chunlei; Zhang, ChuanweiPeriodic driving of a quantum system can significantly alter its energy bands and even change the band topology, opening a completely new avenue for engineering novel quantum matter. Although important progress has been made recently in measuring topological properties of Floquet bands in different systems, direct experimental measurement of full Floquet band dispersions and their topology change is still demanding. Here we directly measure Floquet band dispersions in a periodically driven spin-orbit-coupled ultracold Fermi gas using spin-injection radio-frequency spectroscopy. We observe that the Dirac point originating from two-dimensional spin-orbit coupling can be manipulated to emerge at the lowest or highest two dressed bands by fast modulating Raman laser frequencies, demonstrating topological change of Floquet bands. Our work will provide a powerful tool for understanding fundamental Floquet physics as well as engineering exotic topological quantum matter.Item Operational Role of Retail Bundling and its Implications in a Supply Chain(Wiley-Blackwell) Cao, Q.; Geng, X.; Stecke, Kathryn E.; Zhang, J.; Stecke, Kathryn E.We study the impacts of retail bundling on a supply chain with a manufacturer and a retailer. The retailer orders a primary product from the manufacturer before demand uncertainty materializes, and can retail it in a bundle with a secondary product afterwards. Our findings reveal three effects of bundling. First, bundling can help a retailer mitigate the adverse consequences of demand uncertainty in the primary product and price-discriminate customers of the secondary product. Second, bundling can lower the retailer’s wholesale-price elasticity and partition the retailer’s ordering decision into bundling and no-bundling regions, between which there is a marked drop in the retailer’s optimal order quantity. Third, bundling affects the manufacturer’s wholesale price decision in an unexpected way: The manufacturer may lower the wholesale price when the retailer bundles. Our analysis shows bundling benefits the manufacturer, but can sometimes hurt the retailer. Further, when uncertainty in retail order is considered, while the manufacturer always benefits from retail bundling in expectation, it might be worse off with bundling depending on the realization of the uncertain market size. This explains why retail bundling has been a concern to some major manufacturers whereas they do not prohibit bundling up front. ©2019 Production and Operations Management SocietyItem Optimizing Data Distribution for Loops on Embedded Multicore with Scratch-Pad Memory(Academy Publisher) Gao, Q.; Zhuge, Q.; Zhang, J.; Zhu, G.; Sha, Edwin Hsing-Mean; 0000 0000 3259 5943 (Sha, EHM); 2003002797 (Sha, EHM)Software-controlled Scratch-Pad Memory (SPM) is a desirable candidate for on-chip memory units in embedded multi-core systems due to its advantages of small die area and low power consumption. In particular, data placement on SPMs can be explicitly controlled by software. Therefore, the technique of data distribution on SPMs for multi-core system becomes critical in exploiting the advantages of SPM. Previous research efforts on data allocation did not consider the placement of array data accessed in loops. Loops are the most time-consuming and energy-consuming part for most of the computationintensive applications. In this paper, we propose a highperformance, low-overhead data distribution technique, the Iterational Optimal Loop Data Distribution Algorithm based on dynamic programming. It optimizes data allocation of both scalar and array data for embedded multi-core systems with SPMs. The experimental results show that the IOLDD algorithm reduces the energy consumption by 30.12% and 14.52% on average compared with random data distribution and greedy stretagy, respectively. It also reduces the memory access time by 18.45% and 18.38% on average compared with the random distribution strategy and the greedy strategy, respectively.Item Subduction Initiation Dynamics along a Transform Fault Control Trench Curvature and Ophiolite Ages(Geological Society of America) Zhou, X.; Li, Z. -H; Gerya, T. V.; Stern, Robert J.; Xu, Z.; Zhang, J.; 284885305 (Stern, RJ); Stern, Robert J.Understanding how new subduction zones form is essential for complete articulation of plate tectonic theory. Formation of new subduction zones by collapse of oceanic transform faults or fracture zones is suggested on the basis of empirical evidence. This process has heretofore been investigated with two-dimensional (2-D) numerical models, which thus ignore its intrinsic three-dimensional (3-D) geometry, lateral propagation, and dynamics. Here, we investigate a 3-D thermomechanical model, in which old and thick oceanic lithosphere (plate) is separated by a transform fault from a thinner and younger oceanic plate containing a transform-orthogonal spreading ridge. The results suggest that the older plate starts to sink spontaneously at the ridge-transform fault junction, and then subduction initiation laterally propagates along the transform away from the ridge. Two key factors control the 3-D subduction initiation (SI) dynamics in nature: (1) the age of the sinking plate, which controls its negative buoyancy; and (2) the thermal structure of the overriding plate, which reflects its spreading history. Our numerical models not only shed new light on the SI dynamics of Cenozoic subduction zones (e.g., the Izu-Bonin-Mariana zone in the Pacific Ocean), but also have implications for fossil convergent plate margins (e.g., the Bitlis-Zagros suture zone, west of the Strait of Hormuz). In the latter case, systematic variations in ages of supra-subduction zone ophiolites may reflect diachronous SI and its lateral propagation. ©2018 Geological Society of America.