Direct measurement of thermal conductivity of gold nanowires and nanoribbons at ambient room temperature and 100 °C

2021 ◽  
Vol 129 (24) ◽  
pp. 245108
Author(s):  
Joyce H. Anderson ◽  
Sanjeeva Maithripala ◽  
Mark W. Holtz
Keyword(s):  
Thermal Conductivity ◽  
Direct Measurement ◽  
Room Temperature ◽  
Gold Nanowires ◽  
Ambient Room Temperature

High thermal conductivity of pure dense SiC ceramics prepared via HTPVT

2019 ◽  
Vol 12 (03) ◽  
pp. 1950032 ◽  
Author(s):  
Yuchen Deng ◽  
Yaming Zhang ◽  
Nanlong Zhang ◽  
Qiang Zhi ◽  
Bo Wang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Silicon Carbide ◽  
Grain Size ◽  
Phase Composition ◽  
Room Temperature ◽  
Vapor Transport ◽  
Physical Vapor Transport ◽  
Growth Substrate ◽  
Sic Ceramics ◽  
Evolution Of Microstructure

Pure dense silicon carbide (SiC) ceramics were obtained via the high-temperature physical vapor transport (HTPVT) method using graphite paper as the growth substrate. The phase composition, the evolution of microstructure, the thermal diffusivity and thermal conductivity at RT to 200∘C were investigated. The obtained samples had a relative density of higher than 98.7% and a large grain size of 1[Formula: see text]mm, the samples also had a room-temperature thermal conductivity of [Formula: see text] and with the temperature increased to 200∘C, the thermal conductivity still maintained at [Formula: see text].

scholarly journals Local ferroelectric polarization switching driven by nanoscale distortions in thermoelectric $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aastha Vasdev ◽  
Moinak Dutta ◽  
Shivam Mishra ◽  
Veerpal Kaur ◽  
Harleen Kaur ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Lattice Thermal Conductivity ◽  
Direct Evidence ◽  
Temperature Dependent ◽  
Force Microscopy ◽  
Ferroelectric Domains ◽  
Pdf Analysis ◽  
Ferroelectric Transition Temperature

AbstractA remarkable decrease in the lattice thermal conductivity and enhancement of thermoelectric figure of merit were recently observed in rock-salt cubic SnTe, when doped with germanium (Ge). Primarily, based on theoretical analysis, the decrease in lattice thermal conductivity was attributed to local ferroelectric fluctuations induced softening of the optical phonons which may strongly scatter the heat carrying acoustic phonons. Although the previous structural analysis indicated that the local ferroelectric transition temperature would be near room temperature in $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$ Sn 0.7 Ge 0.3 Te , a direct evidence of local ferroelectricity remained elusive. Here we report a direct evidence of local nanoscale ferroelectric domains and their switching in $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$ Sn 0.7 Ge 0.3 Te using piezoeresponse force microscopy(PFM) and switching spectroscopy over a range of temperatures near the room temperature. From temperature dependent (250–300 K) synchrotron X-ray pair distribution function (PDF) analysis, we show the presence of local off-centering distortion of Ge along the rhombohedral direction in global cubic $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$ Sn 0.7 Ge 0.3 Te . The length scale of the $${\text {Ge}}^{2+}$$ Ge 2 + off-centering is 0.25–0.10 Å near the room temperatures (250–300 K). This local emphatic behaviour of cation is the cause for the observed local ferroelectric instability, thereby low lattice thermal conductivity in $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$ Sn 0.7 Ge 0.3 Te .

Thermal Conductivity of Room Temperature Deep Eutectic Solvents

2021 ◽  
Author(s):  
Noor Albayati ◽  
Mohammed Kadhom ◽  
Ghassan Abdullah ◽  
Suhaib Salih
Keyword(s):  
Thermal Conductivity ◽  
Room Temperature ◽  
Deep Eutectic Solvents

scholarly journals Above-room-temperature giant thermal conductivity switching in spintronic multilayers

2021 ◽  
Vol 118 (4) ◽  
pp. 042409
Author(s):  
Hiroyasu Nakayama ◽  
Bin Xu ◽  
Sotaro Iwamoto ◽  
Kaoru Yamamoto ◽  
Ryo Iguchi ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Room Temperature ◽  
Conductivity Switching

scholarly journals Research on Thermal Stability and Properties of Ca3ZrSi2O9 as Potential T/EBC Materials

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 583
Author(s):  
Yangyang Pan ◽  
Bo Liang ◽  
Yaran Niu ◽  
Dijuan Han ◽  
Dongdong Liu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Stability ◽  
Fracture Toughness ◽  
Room Temperature ◽  
Coefficient Of Thermal Expansion ◽  
Atmospheric Plasma ◽  
Thermal Barrier ◽  
Mechanical And Thermal Properties ◽  
Self Healing ◽  
Barrier Coating

In this study, a new coating material for thermal barrier coating (TBC) or environment barrier coating (EBC) application, Ca3ZrSi2O9 (CZSO), was synthesized and prepared by atmospheric plasma spray (APS) technology. The evolution of the phases and microstructures of the coatings with different thermal-aged were characterized by XRD, XRF, EDS and SEM, respectively. The thermal stability was measured by TG-DTA and DSC. The mechanical and thermal properties, including Vickers hardness (HV), fracture toughness (KIC), thermal conductivity () and coefficient of thermal expansion (CTE) were focused on. It was found that the as-sprayed CZSO coating contained amorphous phase. Crystalline transformation happened at 900–960 ∘C and no mass changes took place from room temperature (RT) to 1300 ∘C. The phenomena of microcrack self-healing and composition uniformity were observed during thermal aging. The of coating was very low at about 0.57–0.80 Wm−1K−1 in 200–1200 ∘C. The combined properties indicated that the CZSO coating might be a potential T/EBC material.

Thermoelectric Properties of Semiconducting Intermetallic Compounds: FeGa3and RuGa3

2003 ◽  
Vol 793 ◽  
Author(s):  
Y. Amagai ◽  
A. Yamamoto ◽  
C. H. Lee ◽  
H. Takazawa ◽  
T. Noguchi ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
High Temperature ◽  
Seebeck Coefficient ◽  
Transport Properties ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
High Seebeck Coefficient

ABSTRACTWe report transport properties of polycrystalline TMGa3(TM = Fe and Ru) compounds in the temperature range 313K<T<973K. These compounds exhibit semiconductorlike behavior with relatively high Seebeck coefficient, electrical resistivity, and Hall carrier concentrations at room temperature in the range of 1017- 1018cm−3. Seebeck coefficient measurements reveal that FeGa3isn-type material, while the Seebeck coefficient of RuGa3changes signs rapidly from large positive values to large negative values around 450K. The thermal conductivity of these compounds is estimated to be 3.5Wm−1K−1at room temperature and decreased to 2.5Wm−1K−1for FeGa3and 2.0Wm−1K−1for RuGa3at high temperature. The resulting thermoelectric figure of merit,ZT, at 945K for RuGa3reaches 0.18.

Abstract P189: Method of Cold Saline Storage for Prehospital Induced Hypothermia

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Mitch Kampmeyer ◽  
Clifton W Callaway
Keyword(s):  
Room Temperature ◽  
Prehospital Care ◽  
Rank Test ◽  
Induced Hypothermia ◽  
Ambient Conditions ◽  
Storage Unit ◽  
Cold Saline ◽  
Kaplan Meier ◽  
Significant Difference ◽  
Ambient Room Temperature

Recent research supports the use of cold IV fluid as a method for initiating therapeutic hypothermia in post-cardiac arrest resuscitation. However, prehospital care programs employing this treatment have encountered various difficulties. Barriers to prehospital induced hypothermia protocols include the lack of effective or economically reasonable methods to maintain cold saline in the field. Objective. Determine the time that a standard commercial cooler can maintain two 1-liter normal saline solution (NSS) bags below 4°C in 3 different environments. Methods. Environments simulating an ambulance compartment were created for the experiment. NSS temperatures were continuously recorded inside a standard commercial cooler with or without ice packs (IPs) under one of three scenarios: ambient room temperature (25°C) without (IPs), ambient room temperature with IPs and 50°C ambient temperature with IPs. Four trials under each condition were performed. Time to warm to 4°C was compared using Kaplan-Meier log rank test. Results. In a room temperature environment with IPs, the NSS warmed to 4°C in a mean interval of 29 hrs 53 mins versus in ambient room temperature without IPs (1 hr 21 mins) versus in constant hot environment of 50°C with IPs (10 hrs 50 mins). A significant difference was found between the three environments (log-rank =17.90, dF =2, p =0.0001). Conclusions. Low technology methods in the form of a cooler and IPs can provide cold NSS storage for longer than a full 24 hour shift in a room temperature ambulance. In hot ambient conditions, 4°C NSS can be maintained for nearly 11 hours using this method. This model exhibits an economical, easily deployable cold saline storage unit.

A Facile Room-Temperature Synthesis of Gold Nanowires by Oxalate Reduction Method

2007 ◽  
Vol 111 (38) ◽  
pp. 14150-14156 ◽  
Author(s):  
S. Navaladian ◽  
C. M. Janet ◽  
B. Viswanathan ◽  
T. K. Varadarajan ◽  
R. P. Viswanath
Keyword(s):  
Room Temperature ◽  
Reduction Method ◽  
Gold Nanowires ◽  
Temperature Synthesis ◽  
Room Temperature Synthesis

scholarly journals Diameter and Length Effect on Diffusive-Ballistic Phonon Transport in a Carbon Nanotube

2007 ◽  
Author(s):  
Junichiro Shiomi ◽  
Shigeo Maruyama
Keyword(s):  
Thermal Conductivity ◽  
Room Temperature ◽  
Single Walled Carbon Nanotubes ◽  
Phonon Transport ◽  
Boundary Resistance ◽  
Gradual Transition ◽  
Length Effect ◽  
Control Techniques ◽  
Non Equilibrium Molecular Dynamics ◽  
Walled Carbon Nanotubes

We report a non-equilibrium molecular dynamics (MD) study on heat conduction of finite-length single-walled carbon nanotubes (SWNTs). The length and diameter dependences of the thermal conductivity are quantified for a range of nanotube-lengths up to a micrometer at room temperature using two different temperature control techniques. A thorough investigation was carried out on the influence of intrinsic thermal boundary resistance between the temperature-controlled layers and the rest of the SWNT. The trend of length effect indicates a gradual transition from nearly pure ballistic phonon transport to diffusive-ballistic phonon transport. The nearly pure ballistic phonon transport was also confirmed by the minor diameter-dependence of thermal conductivity for short SWNTs. For longer SWNTs with stronger diffusive effect, the thermal conductivity is larger for SWNTs with smaller diameters.

Long-term Room Temperature Instability in Thermal Conductivity of InGaZnO Thin Films

MRS Advances ◽  
2016 ◽  
Vol 1 (22) ◽  
pp. 1631-1636 ◽  
Author(s):  
Boya Cui ◽  
D. Bruce Buchholz ◽  
Li Zeng ◽  
Michael Bedzyk ◽  
Robert P. H. Chang ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Room Temperature ◽  
Storage Time ◽  
Laser Deposition ◽  
Low Oxygen ◽  
X Ray Diffraction ◽  
3Ω Method ◽  
X Ray

ABSTRACTThe cross-plane thermal conductivities of InGaZnO (IGZO) thin films in different morphologies were measured on three occasions within 19 months, using the 3ω method at room temperature 300 K. Amorphous (a-), semi-crystalline (semi-c-) and crystalline (c-) IGZO films were grown by pulsed laser deposition (PLD), followed by X-ray diffraction (XRD) for evaluation of film quality and crystallinity. Semi-c-IGZO shows the highest thermal conductivity, even higher than the most ordered crystal-like phase. After being stored in dry low-oxygen environment for months, a drastic decrease of semi-c-IGZO thermal conductivity was observed, while the thermal conductivity slightly reduced in c-IGZO and remained unchanged in a-IGZO. This change in thermal conductivity with storage time can be attributed to film structural relaxation and vacancy diffusion to grain boundaries.

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