14 research outputs found

    Synthesis of Quinolines through Three-Component Cascade Annulation of Aryl Diazonium Salts, Nitriles, and Alkynes

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    An efficient and rapid synthesis of multiply substituted quinolines is described. This method is enabled by a three-component cascade annulation of readily available aryl diazonium salts, nitriles, and alkynes. This reaction is catalyst- and additive-free. Various aryl diazonium salts, nitriles, and alkynes can participate in this transformation, and the yields are up to 83%

    Near-Field Energy Extraction with Hyperbolic Metamaterials

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    Although blackbody radiation described by Planckā€™s law is commonly regarded as the maximum of thermal radiation, thermal energy transfer in the near-field can exceed the blackbody limit due to the contribution from evanescent waves. Here, we demonstrate experimentally a broadband thermal energy extraction device based on hyperbolic metamaterials that can significantly enhance near-field thermal energy transfer. The thermal extractor made from hyperbolic metamaterials does not absorb or emit any radiation but serves as a transparent pipe guiding the radiative energy from the emitter. At the same gap between an emitter and an absorber, we observe that near-field thermal energy transfer with thermal extraction can be enhanced by around 1 order of magnitude, compared to the case without thermal extraction. The novel thermal extraction scheme has important practical implications in a variety of technologies, e.g., thermophotovoltaic energy conversion, radiative cooling, thermal infrared imaging, and heat assisted magnetic recording

    Perfect Thermal Emission by Nanoscale Transmission Line Resonators

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    Thermal radiation with a narrow-band emission spectrum is of great importance in a variety of applications such as infrared sensing, thermophotovoltaics, radiation cooling, and thermal circuits. Although resonant nanophotonic structures such as metamaterials and nanocavities have been demonstrated to achieve the narrow-band thermal emission, maximizing their radiation power toward perfect emission still remains challenging. Here, based on the recently developed quasi-normal mode theory, we prove that thermal emission from a nanoscale transmission line resonator can always be maximized by tuning the waveguiding loss of the resonator or bending the structure. By use of nanoscale transmission line resonators as basic building blocks, we experimentally demonstrate a new type of macroscopic perfect and tunable thermal emitters. Our experimental demonstration in conjunction with the general theoretical framework from the quasi-normal mode theory lays the foundation for designing tunable narrow-band thermal emitters with applications in thermal infrared light sources, thermal management, and infrared sensing and imaging

    Observation of Near-Field Thermal Radiation between Coplanar Nanodevices with Subwavelength Dimensions

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    With the continuous advancement of nanotechnology, nanodevices have become crucial components in computing, sensing, and energy conversion applications. The structures of nanodevices typically possess subwavelength dimensions and separations, which pose significant challenges for understanding energy transport phenomena in nanodevices. Here, on the basis of a judiciously designed thermal photonic nanodevice, we report the first measurement of near-field energy transport between two coplanar subwavelength structures over temperature bias up to āˆ¼190 K. Our experimental results demonstrate a 20-fold enhancement in energy transfer beyond blackbody radiation. In contrast with the well-established near-field interactions between two semi-infinite bodies, the subwavelength confinements in nanodevices lead to increased polariton scattering and reduction of supporting photonic modes and, therefore, a lower energy flow at a given separation. Our work unveils exciting opportunities for the rational design of nanodevices, particularly for coplanar near-field energy transport, with important implications for the development of efficient nanodevices for energy harvesting and thermal management

    Folding-Promoted TBACl-Mediated Chemo- and Regioselective Demethylations of Methoxybenzene-Based Macrocyclic Pentamers

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    Tetrabutylammonium chloride (TBACl) salt alone has not been shown previously to be capable of removing methoxy groups. It is demonstrated here that the use of TBACl achieves efficient folding-promoted chemo- and regioselective demethylations, eliminating up to two out of five methyl groups situated in similar macrocyclic chemical microenvironments

    Ultracompliant Heterogeneous Copperā€“Tin Nanowire Arrays Making a Supersolder

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    Due to the substantial increase in power density, thermal interface resistance that can constitute more than 50% of the total thermal resistance has generally become a bottleneck for thermal management in electronics. However, conventional thermal interface materials (TIMs) such as solder, epoxy, gel, and grease cannot fulfill the requirements of electronics for high-power and long-term operation. Here, we demonstrate a high-performance TIM consisting of a heterogeneous copperā€“tin nanowire array, which we term ā€œsupersolderā€ to emulate the role of conventional solders in bonding various surfaces. The supersolder is ultracompliant with a shear modulus 2ā€“3 orders of magnitude lower than traditional solders and can reduce the thermal resistance by two times as compared with the state-of-the-art TIMs. This supersolder also exhibits excellent long-term reliability with >1200 thermal cycles over a wide temperature range. By resolving this critical thermal bottleneck, the supersolder enables electronic systems, ranging from microelectronics and portable electronics to massive data centers, to operate at lower temperatures with higher power density and reliability

    Demographic and clinical characteristics of ESRD and control groups.

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    <p>Unless otherwise indicated, data are meanĀ±standard deviations.</p><p>NAā€Š=ā€Šnot applicable. MMSE ā€Š=ā€Š Mini-mental status examination.</p><p><sup>*</sup><i>P</i> values are two sided.</p>#<p>For sex composition, Ļ‡<sup>2</sup>ā€Š=ā€Š0.000 and Ī½ā€Š=ā€Š1.</p>ā–“<p>There were two patients in the ESRD group and three persons in the control group with a history of smoking.</p>$<p>There were 17 inpatients in the ESRD group.</p

    Additional file 2: of Tumor-infiltrating mast cells predict prognosis and gemcitabine-based adjuvant chemotherapeutic benefit in biliary tract cancer patients

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    Figure S1. Association between CD8+ T cells and overall survival in the discovery set and validation set. (A,C) Kaplan-Meier analysis of overall survival in the discovery set and validation set based on CD8+ T cells infiltration (B,D) Kaplan-Meier analysis of overall survival in the discovery set and validation set based on combination of TIMs and CD8+ T cells infiltration. (TIFF 652 kb

    Temperature-Gated Thermal Rectifier for Active Heat Flow Control

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    Active heat flow control is essential for broad applications of heating, cooling, and energy conversion. Like electronic devices developed for the control of electric power, it is very desirable to develop advanced all-thermal solid-state devices that actively control heat flow without consuming other forms of energy. Here we demonstrate temperature-gated thermal rectification using vanadium dioxide beams in which the environmental temperature actively modulates asymmetric heat flow. In this three terminal device, there are two switchable states, which can be regulated by global heating. In the ā€œRectifierā€ state, we observe up to 28% thermal rectification. In the ā€œResistorā€ state, the thermal rectification is significantly suppressed (<1%). To the best of our knowledge, this is the first demonstration of solid-state active-thermal devices with a large rectification in the Rectifier state. This temperature-gated rectifier can have substantial implications ranging from autonomous thermal management of heating and cooling systems to efficient thermal energy conversion and storage
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