14 research outputs found
Synthesis of Quinolines through Three-Component Cascade Annulation of Aryl Diazonium Salts, Nitriles, and Alkynes
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
Although
blackbody radiation described by Planckās 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
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
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
ā¼190 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
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
Brain regions with abnormal ReHo in patients with ESRD compared with control subjects.
<p>Lā=āleft, Rā=āright, MNIā=āMontreal Neurological Institute.</p
Ultracompliant Heterogeneous CopperāTin Nanowire Arrays Making a Supersolder
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 copperātin
nanowire array, which we term āsupersolderā to emulate
the role of conventional solders in bonding various surfaces. The
supersolder is ultracompliant with a shear modulus 2ā3 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.
<p>Unless otherwise indicated, data are meanĀ±standard deviations.</p><p>NAā=ānot applicable. MMSE ā=ā 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=ā0.000 and Ī½ā=ā1.</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
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
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 āRectifierā
state, we observe up to 28% thermal rectification. In the āResistorā
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