878 research outputs found
sj-docx-1-tam-10.1177_17588359241229661 – Supplemental material for Efficacy and safety of raltitrexed-eluting CalliSpheres® bead transarterial chemoembolization in patients with intermediate-stage hepatocellular carcinoma: a single-arm, prospective study
No full textSupplemental material, sj-docx-1-tam-10.1177_17588359241229661 for Efficacy and safety of raltitrexed-eluting CalliSpheres® bead transarterial chemoembolization in patients with intermediate-stage hepatocellular carcinoma: a single-arm, prospective study by Zhanguo Sun, Dechao Jiao, Yi Fang, Yiming Liu, Kaihao Xu, Chengzhi Zhang, Yuanhao Huang and Xinwei Han in Therapeutic Advances in Medical Oncology</p
Micro-embossing formability of a superlight dual-phase Mg-Li alloy processed by high-pressure torsion
No full textMicro‐embossing tests are performed on a coarse‐grained (CG) and an ultrafine‐grained (UFG) dual‐phase Mg–Li alloy processed by high‐pressure torsion (HPT) using different widths of the female die at ambient temperature under a force of 9 kN. The surface topography, rib profiles, and microstructures of the cross‐sections are measured by scanning electron microscopy, confocal scanning laser microscopy, and optical microscopy, respectively. The interactive effects of the cavity widths of the female die and dual phases on the formability of micro‐embossing are analyzed. Numerical simulations are performed to study the effects of the dual‐phases on the filling behavior of the CG and UFG alloys. The results show that a UFG Mg–Li alloy reduces the adverse effects of dual phases on the formability of micro‐embossing. Micro‐channel arrays with channel widths ranging from 50 to 200 µm are fabricated with good geometrical accuracy using a UFG dual‐phase alloy at ambient temperature, thereby establishing the excellent potential for using UFG dual‐phase Mg–Li alloys processed by HPT for applications in micro‐forming
Microhardness, microstructure and tensile behavior of an AZ31 magnesium alloy processed by high-pressure torsion
No full textAn AZ31 magnesium alloy was processed by high-pressure torsion (HPT) at room temperature under an imposed pressure of 6.0 GPa. Microstructural analysis showed that the HPT processing introduced significant grain refinement with a reduction in grain size from ~35 ?m in the initial annealed condition to ~110 nm after ten turns of HPT. Microhardness measurements showed that a reasonable level of hardness homogeneity was achieved across the disk processed through ten turns. The results from tensile testing demonstrated that the ultrafine-grained (UFG) AZ31 alloy processed by HPT exhibits high ductility with a maximum elongation of ~400 % at the relatively low testing temperature of 423 K. The results confirm that the UFG AZ31 magnesium alloy processed by HPT through ten turns has a strong potential for use in micro-forming applications
Dry sliding wear of an AZ31 magnesium alloy processed by equal-channel angular pressing
No full textA magnesium AZ31 alloy was processed by equal-channel angular pressing (ECAP) for up to 8 passes to reduce the grain size to ~1.0 ?m. Following ECAP, microhardness measurements were taken to evaluate the mechanical properties of the material. Ball-on-disc dry sliding tests were conducted to compare the wear behaviour of the as-received alloy and the alloy processed by ECAP. The surface topography and volume loss were recorded for all samples. The results show that the fluctuations and average values of the coefficient of friction are improved after processing by ECAP. In addition, there is a decrease in the wear depth and volume loss with increasing numbers of ECAP passes. The ECAP-processed alloy has a higher wear resistance than the unprocessed alloy and it is a suitable candidate material for use in industrial application
AccidentBlip: Agent of Accident Warning Based on MA-Former
No full textIn complex transportation systems, accurately sensing the surrounding environment and predicting the risk of potential accidents is crucial. Most existing accident prediction methods are based on temporal neural networks, such as RNN and LSTM. Recent multimodal fusion approaches improve vehicle localization through 3D target detection and assess potential risks by calculating inter-vehicle distances. However, these temporal networks and multimodal fusion methods suffer from limited detection robustness and high economic costs. To address these challenges, we propose AccidentBlip, a vision-only framework that employs our self-designed Motion Accident Transformer (MA-former) to process each frame of video. Unlike conventional self-attention mechanisms, MA-former replaces Q-former's self-attention with temporal attention, allowing the query corresponding to the previous frame to generate the query input for the next frame. Additionally, we introduce a residual module connection between queries of consecutive frames to enhance the model's temporal processing capabilities. For complex V2V and V2X scenarios, AccidentBlip adapts by concatenating queries from multiple cameras, effectively capturing spatial and temporal relationships. In particular, AccidentBlip achieves SOTA performance in both accident detection and prediction tasks on the DeepAccident dataset. It also outperforms current SOTA methods in V2V and V2X scenarios, demonstrating a superior capability to understand complex real-world environments
Optical based thermal probing and characterization
Full text linkOptical methods are promising tools for small-scale thermal probing and characterization. A lab-developed photothermal (PT) technique provides a noncontact method to characterize the thermal transport along the thickness direction of a multilayered film by analyzing the phase shift of the thermal radiation from the sample’s surface. Aiming to reduce the calibration in the phase shift method, a new amplitude method is developed on the basis of the amplitude of the thermal radiation signal. The new method successfully performs the thermal measurements for chemical vapor deposited SiC films, thermally oxidized SiO2 film on silicon substrates, and spider silk films. Furthermore, weak-sensitivity to the thermal contact resistance enables the amplitude method to lower the effect of thermal contact resistance on thermal conductivity determination. The normalized amplitude ratio of a high frequency to a low frequency provides a reliable way to evaluate the effusivity ratio of the film to that of the substrate. For spider silk films, the contribution to the thermal conductivity from -helices and antiparallel -sheets in silk proteins against the temperature has been studied.
Raman spectroscopy is better than PT since its scatterings involve not only the structure information of a sample but also physical properties, like temperature and stress. The edge area of a mechanically cleaved Si wafer is studied using Raman spectroscopy. The appearance of nanocrystals there is proved and it accounts for the abnormal increase in Raman intensity when the grain size of nanocrystals varies from 20 to 10 nm. For transient thermal probing and characterization, a time-domain differential Raman technique is developed using a square-wave modulated laser. The varying duty cycle of the modulation signal realizes controlled heating and transient thermal probing based on Raman thermometry and transient electrothermal technique. A validation experiment is conducted on a tipless Si cantilever. Physical models are later constructed to simulate the variation of the cumulative Raman spectra over one excitation period and to determine the thermal diffusivity of the cantilever. The resulting thermal diffusivity is well agreed with the theoretically determined reference value.</p
Author's personal copy Cross-plane thermal transport in micrometer-thick spider silk films
No full textThis article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. a b s t r a c t This work reports on the first study of thermal transport capacity in the thickness direction (wmm scale) for spider silk films. Fresh (minimally processed) and hexafluoroisopropanol (HFIP) films of Nephila clavipes and Latrodectus hesperus major ampullate silk are studied. Detailed Raman spectroscopy reveals that the fresh films have more crystalline secondary protein structures such as antiparallel b-sheets than the HFIP films for N. clavipes. For N. clavipes, the randomly distributed antiparallel b-sheets in fresh films have nearly no effect in improving thermal conductivity in comparison with HFIP films. For L. hesperus, the films mainly consist of a-helices and random coils while the fresh film has a higher concentration of a-helices. The higher concentration of a-helices in fresh films gives rise to a higher heat capacity than HFIP films, while the thermal conductivity shows little effect from the a-helices concentration. Thickened HFIP films are heated at different temperatures to study the effect of heat treatment on structure and thermal transport capacity. These experiments demonstrate that a-helices are formed by thermal treatment and that thermal effusivity increases with the appearance of a-helices in films
Thermal transport in DNA
Full text linkThermal transport in DNA is systematically studied to facilitate the development of DNA-based nanoelectronics in thermal management aspect. Synthesis of crystalline DNA-composited microfiber and microfilm, DNA nanofiber and DNA nanofiber array are developed in sequence to enable the thermal transport study in them. Thermo-physical properties, including thermal conductivity, thermal diffusivity, and volumetric heat capacity, for all of the DNA samples are reported. The thermal conductivity of DNA microfiber is evaluated to be 0.33 W/m·K at room temperature. With the formation of crystalline DNA-NaCl complexes, DNA molecules are speculated to be aligned with the crystal structure of NaCl during crystallization, which results in a significant enhancement of thermal transport. The thermal conduction can also be improved by eliminating structural defects in DNA samples based on the newly-established thermal reffusivity theory. Thermal reffusivity is the inverse of thermal diffusivity and is introduced to quantitatively evaluate phonon scattering induced by structural defects. The structural size for defect-induced phonon scattering is determined to be 0.8 nm for DNA microfiber, in the same order of magnitude as the characteristic size of DNA. As the structural size for defect-induced phonon scattering approaches infinity, the thermal transport potential in defect-free material can be reached. By estimation, the thermal conductivity/diffusivity will be promoted by 36~61% without structural defects in DNA microfiber. Compared to microfiber, DNA nanofiber possesses a higher thermal conductivity due to more condensed and oriented structures, as well as less structural defects. The structural size for defect-induced phonon scattering is 1.6 nm in DNA nanofiber, twice of that in DNA microfiber. The thermal conductivity of DNA nanofiber with perfect structure is predicted to reach 2.3 W/m·K. In addition, nanoscale Ir thin film on DNA microfiber shows a similar intrinsic electrical resistivity as bulk Ir, which is proposed to be preserved by coherent quantum tunneling and diffusive thermal hopping for electron transport in DNA.</p
Thermal and thermomechanical phenomena in laser material interaction
No full textIn recent years, laser technology has been widely used in materials processing, non-destructive detecting and characterizing. Knowledge of thermal and thermomechanical phenomena in laser material interaction is of great importance in terms of understanding and optimizing these processes. In this thesis, several aspects of these thermal and thermomechanical phenomena are studied. First, the photoacoustic (PA) wave induced by periodical laser heating is studied considering thermal and optical properties and geometry of the multilayer structure. An apparatus is developed to measure thermal conductivities up to a frequency of 20 kHz. Thermal conductivities of thin films and bulk materials with mirror-like or rough surfaces are successfully measured. Second, a generalized solution for the temperature and the thermoelastic wave induced by pulsed laser heating is formulated considering the non-Fourier effect and the coupling effect between temperature and strain rate. Calculation results reveal that with the same maximum surface temperature increase, a shorter pulsed laser induces a much stronger stress wave. The non-Fourier effect results in a higher surface temperature increase, but a weaker stress wave. The coupling effect attenuates the thermoelastic wave and extends its duration. Third, the temperature and the thermoelastic wave in a metal subjected to ultrashort pulsed laser heating are investigated implementing two-step heat transfer and coupling between lattice temperature and strain rate. Two-step heat transfer results in a lower peak surface temperature, a slower temperature variation, and a weaker stress. Moreover, the thermoelastic wave experiences a weaker attenuation and pulse width expansion. With the same surface temperature increase in lattice, the shorter the laser pulse, the stronger the stress wave and its attenuation. Finally, laser material interaction is studied using molecular dynamics simulations when phase change takes place. During the melting process, the solid-liquid interface moves much slower than the local sound, while the liquid-vapor interface moves as fast as the local equilibrium atoms. Superheating is observed at the melting interface. The laser-ablated material is found to burst out of the target as fast as a thousand meters per second. Displacement and stress waves, as well as formation of nanoparticles are clearly observed during laser material interaction
NMR relaxation in synthetic porous media
No full textDue to their central importance in interpreting NMR logs, the NMR relaxation mechanisms in rocks are being thoroughly investigated by the industry. The bulk fluid response and the surface relaxivity are currently better characterized than is the diffusional relaxation. This latter T2 relaxation mechanism is due to the diffusion of the molecules across the strong internal field gradients generated by the susceptibility contrast between rock and pore fluid when the rock is placed in a magnetic field. The CPMG T2 measurement sequence is unable to refocus the spins effectively, since they see a time-varying internal field. This contributes an additional signal loss mechanism that is not present in a simple Ti measurement.
To better characterize this diffusional loss mechanism, the T2 relaxation in synthetic mono-disperse porous media were measured in the lab at room temperature as a function of pore size at 2 MHz. Since the samples were oil-wet, decane was used as the pore fluid. The results are compared to higher field data (85 MHz) and to the relaxation of brine in Berea sandstone at low field.
The author observed diffusional relaxation for these samples. As expected, the mono-disperse samples could be characterized by a single exponential decay constant. For small values of the refocusing time T (the inter-echo CPMG pulse spacing or interpulse spacing time), the T2 rate was proportional to t. For large values of x, the T2 relaxation was independent of the refocusing time x. Over the entire x regime, this T2 loss mechanism had a very well-characterized simple inverse dependence on pore radius
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