- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Development of a high strength Al–Zn–Si–Mg–Cu alloy for selective laser melting
摘要： Despite additive manufacturing processes are already widely used in several industrial applications, there are few materials that are specifically designed and optimized for these technologies. Currently, only few Al alloys are available on the market and employed for 3D printing of structural parts. In particular, SieMg bearing alloys are the most common Al alloys for additive manufacturing, featuring high processability but moderate mechanical properties. By this work, we studied the effect of Si addition on the hot cracking susceptibility of a high strength AleZneMgeCu alloy. A preliminary activity has been carried out by blending AleZneMgeCu and AleSieMg powders and analysing their microstructure and properties achieved after selective laser melting. Eventually a new AleZneSieMgeCu alloy has been designed, produced as powder alloy by gas atomization and tested. The microstructure and phase transformations of the new alloy has been investigated by synchrotron X-ray diffraction, differential scanning calorimetry and microscope analysis. The AleZneSieMgeCu alloy processed by selective laser melting featured a relative density of 99.8%, no hot cracks were noticed within the investigated microstructures. The ability of the new alloy to respond to aging starting from both as built and solution annealed conditions has been also evaluated. A good response to direct aging (directly from as built condition) was demonstrated, featuring yield strength and ultimate tensile strength of 402 and 449 MPa, respectively, and hardness of 174 HV after optimized aging at 165 (cid:1)C for 2 h.
关键词： Differential scanning calorimetry,Metal additive manufacturing,Mechanical properties,Synchrotron X-ray diffraction,High strength Al alloy
更新于2025-11-21 11:18:25
-
Physical, Thermal and Spectroscopic Studies on Biofield Treated p-Dichlorobenzene
摘要： Para-dichlorobenzene (p-DCB) is widely used as a chemical intermediate in manufacturing of dyes, pharmaceuticals, polymers and other organic synthesis. The aim of present study was to evaluate the impact of biofield treatment on physical, thermal, and spectroscopic properties of p-dichlorobenzene. The p-dichlorobenzene sample was divided into two groups that served as treated and control. The treated group received Mr. Trivedi’s biofield treatment. Subsequently the control and treated samples were evaluated using X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and UV-Vis spectroscopy. XRD result showed an increase in crystallite size (4.93%) along with alteration in peak intensity of treated sample as compared to control. Furthermore, DSC analysis results showed that the latent heat of fusion of treated p-dichlorobenzene was considerably reduced by 8.66% as compared to control. The reduction in melting point of treated sample (54.99°C) was also observed as compared to control (57.01°C) p-dichlorobenzene. Moreover, TGA/DTG studies showed that Tmax (temperature, at which sample lost maximum of its weight) was increased by 6.26% and weight loss per degree celsius (°C) was decreased by 12.77% in biofield treated p-dichlorobenzene as compared to control sample. It indicates that thermal stability of treated p-dichlorobenzene sample might increase as compared to control sample. However, no change was found in UV-Vis spectroscopic character of treated p-dichlorobenzene as compared to control. These findings suggest that biofield treatment has significantly altered the physical and thermal properties of p-dichlorobenzene, which could make it more useful as a chemical intermediate.
关键词： Differential scanning calorimetry,Para-dichlorobenzene,Thermogravimetric analysis,and UV-Visible spectroscopy,Biofield treatment,X-ray diffraction study
更新于2025-09-23 15:23:52
-
Thioxanthone-functionalized 1,6-heptadiene as monomeric photoinitiator
摘要： The synthesis of the first photoinitiator (PI) based on thioxanthone (TX) with 1,6-heptadiene structure is described. This PI (TXdMA) absorbs in the near UV–vis region (435–439 nm; with absorption redshift≈50 nm and ε values comparable to TX). Photopolymerization results demonstrate that although TXdMA is not an effective one-component polymerizable photoinitiator, it can successfully initiate photopolymerization of poly(ethylene glycol) diacrylate (PEGDA, Mn = 250 D) and trimethylolpropane triacrylate (TMPTA) in the presence of bis-(4-tert-butylphenyl)-iodonium hexafluorophosphate (Iod) similar to TX/Iod. TXdMA exhibits better migration stability than TX. Absorption, fluorescence, steady state photolysis and cyclic voltammetry experiments are carried out to investigate the photochemical mechanisms.
关键词： Photopolymerization,Monomeric photoinitiators,Fluorescence,Photo differential scanning calorimetry
更新于2025-09-23 15:23:52
-
Esters of 4-nitrocinnamic acids and 4-halogene-4’-hydroxyazobenzenes – synthesis, mesogenic and optical studies
摘要： Six new compounds were synthesized that have no alkyl chains in their structure: 4-nitrocinnonates of 4-hydroxyazobenzene, 4-nitro-4'-hydroxyazobenzene, 4-fluoro-4'-hydroxyazobenzene, 4-chloro-4'-hydroxyazobenzene, 4-bromo-4'-hydroxyazobenzene, and 4-iodo-4'-hydroxyazobenzene. Using the polarizing microscopy and differential scanning calorimetry, enthalpies and temperatures of phase transitions were determined. All investigated compounds have an enantiotropic nematic phase. These compounds proved to be extremely thermally stable. Thermal decomposition was observed in temperatures above 300°C. Investigated compounds contain two different chromophore groups (i.e. azo and ethene moieties), which influenced the complex trans–cis isomerization processes of both groups (three time-separated processes were observed). It was shown that the presence of the ethene group significantly shifts the π-π* band towards higher energies. The substituent polarity in the azo group also affected the energy of this absorption band. A weak luminescence effect was observed in the 4-nitrocinnonates of 4-hydroxyazobenzene compound.
关键词： nematic,luminescence,Azobenzenes,trans–cis isomerization,polarizing microscopy,DSC calorimetry
更新于2025-09-23 15:23:52
-
Thermal Characterization of a PPy/PLA Composite by Photoacoustic Calorimetry and Photopyroelectric Techniques
摘要： Recently, conductive polymers have attracted attention in the field of advanced materials. Conducting polymers include polypyrrole (PPy), which is a material with commercial applications due to its stability and electrical conductivity. As technology demands increasingly flexible devices, PPy was mixed with a biodegradable and flexible polymer, polylactic acid, in order to create a composite possessing of newer properties. As it is a new material, thermal properties of this composite such as thermal diffusivity, thermal effusivity, specific heat capacity, and thermal conductivity have been investigated through the application of photoacoustic calorimetry and photopyroelectric techniques.
关键词： PPy/PLA composite,Photoacoustic calorimetry,Polymer,Photopyroelectric technique
更新于2025-09-23 15:22:29
-
[IEEE 2017 International Renewable and Sustainable Energy Conference (IRSEC) - Tangier (2017.12.4-2017.12.7)] 2017 International Renewable and Sustainable Energy Conference (IRSEC) - Mapping of the Composition of Soils Naturally Deposited on PV Modules Anywhere in Morocco
摘要： This article constitutes a preliminary phase for the performance of a national cartography of the composition of soils naturally deposited on photovoltaic modules installed in sites of different climates. To do this, a climatic zoning of Morocco according to the De Martonne index was adopted in order to select representative sites concerned with the collection of samples. For the moment, four samples have been collected in Rabat, Errachidia, Agadir and Oujda. These samples were prepared and analyzed. Several analyzes were carried out to determine the physical, chemical and mineralogical composition of these samples. The mineralogical composition was determined via X-Ray Diffraction (XRD) and X-Ray Fluorescence analysis (XF), while characterization of the physical and chemical composition was identified using Differential Scanning Calorimetry (DSC) and Spectroscopy Infrared (IR). The results show the existence of the same abundant constituents namely: Quartz, Calcite, Dolomite, Kaolinite whose percentages differ from a climate to another.
关键词： Soils,Quartz,Calcite,Differential Scanning Calorimetry (DSC),Kaolinite,Climatic zoning,Infrared spectroscopy (IR),X-Ray Diffraction,Photovoltaic modules,Dolomite,Cartography,X-Ray Fluorescence
更新于2025-09-23 15:22:29
-
Scintillation Detectors in Modern High Energy Physics Experiments and Prospect of Their use in Future Experiments
摘要： The scintillation detector (SD) based on organic plastic scintillator (OPS) is one of the basic detectors in HEP experiments. Technologies for production of OPSs as strips and tiles, their optical and physical properties, light collection based on wavelength shifting (WLS) fibers coupled to multipixel vacuum and silicon PMs are presented. SDs are multifunctional: calorimeters, triggers, tracking, time-of-flight and veto systems are the examples of their applications. The use of SDs in many HEP experiments on the search for quarks, new particles and H bosons (D0, ATLAS, CMS), quark-gluon plasma (ALICE), CP violation (LHCb, KLOE), ν-oscillation (MINOS, OPERA), cosmic particles (AMS-02) are discussed. SDs hold great promise for future HEP experiments due to their ability of high segmentation, WLS fiber light collection and multipixel silicon PM readout.
关键词： Fibers,Energy,Calorimetry,Scintillation detectors
更新于2025-09-23 15:21:01
-
[IEEE 2019 21st International Conference on Transparent Optical Networks (ICTON) - Angers, France (2019.7.9-2019.7.13)] 2019 21st International Conference on Transparent Optical Networks (ICTON) - Polarization Modulation Instability in All-Normal Dispersion Microstructured Optical Fibers with sub-ns Pumping
摘要： The CMS lead tungstate (PbWO4) electromagnetic calorimeter (ECAL) has successfully achieved its first goal: the discovery of the Higgs boson in 2012. However, longevity studies show that part of the PbWO4 ECAL will not maintain the required performance due to radiation damage incurred at the HL-LHC. The forward region of the detector will suffer the most from radiation damage, and the ECAL Endcaps (EE) will need to be replaced. A scintillator-based option for the EE replacement, Shashlik EE, is presented in the paper. The Shashlik EE is a sampling calorimeter. Tungsten absorber plates are interleaved with scintillator plates (LYSO or CeF3), with quartz and wavelength-shifting (WLS) capillaries optically coupled to the scintillator plates for light output. The Shashlik EE maintains an excellent energy resolution, but compared to the current PbWO4 EE, it is at least five times greater in radiation hardness and has a module size four times smaller allowing four times higher granularity laterally for pileup mitigation and particle identification. Irradiation tests and beam tests results have confirmed the high performance of the Shashlik EE.
关键词： photondetectors,Calorimetry,solid scintillation detectors
更新于2025-09-23 15:19:57
-
Glass formation in amorphous ZnO films revealed by chip calorimetry
摘要： In this work, we utilize the high heating/cooling rates of chip calorimetry to perform in situ annealing of an inkjet-printed zinc oxide solgel ink consisting of zinc acetate, 2-methoxyethanol, and monoethanolamine and directly observe the thermodynamic signatures of its corresponding structural phase transformations. We find that rapid solvent removal achieved by annealing above the boiling point of the solvent, similar to an industrial drying technique known as flash drying, induces the formation of (cid:1) 98% amorphous zinc oxide films having an unprecedented, largely pronounced glass transition while retaining its semiconductor properties evidenced by field-effect transistor measurements. Thin-films produced at comparable heating rates to those used for calorimetry experiments are used to corroborate these findings using independent measurements. Prepared films exhibit a clear amorphous halo centered about the three most prominent Bragg positions of the wurtzite phase of ZnO and remain thermally stable against crystallization until 250 (cid:3)C have a room temperature thermal conductivity of (cid:1) 1:03–1:4 W m(cid:4)1 K(cid:4)1 (consistent with recent ab initio estimates) with supporting evidence of a structural relaxation near TG consistently observed in both electronic and thermal conductivity.
关键词： semiconductor properties,amorphous ZnO films,glass formation,chip calorimetry,flash drying
更新于2025-09-23 15:19:57
-
[IEEE 2019 IEEE 13th International Conference on ASIC (ASICON) - Chongqing, China (2019.10.29-2019.11.1)] 2019 IEEE 13th International Conference on ASIC (ASICON) - Design of High-Speed Drivers for 56Gb/s PAM4 Optical Communications in CMOS
摘要： We investigate the feasibility of estimating the total energy expenditure (TEE) of a human for walking/running activities with micro-Doppler signatures. Doppler radar can capture micro-Doppler signatures produced from limb motions when a human moves. As the micro-Doppler signatures contain information regarding limb movement, TEE can be estimated by analyzing the Doppler spectrogram. To understand the relationship between the TEE and micro-Doppler signatures, basic arm and leg motions are measured by the Doppler radar, whereas a respiratory gas analyzer measures the volume of exchanged respiratory gas (O2 and CO2) to obtain a reference TEE. The area of micro-Doppler signatures in a spectrogram has been suggested to serve as key information to estimate TEE. For the verification of the suggested approach, TEE was measured for seven human subjects, who performed walking and running activities on a treadmill at five different speeds using both the Doppler radar and the respiratory gas analyzer. We confirm that strong correlations exist between the micro-Doppler area and the TEE. Finally, a regression model for walking and running activities is developed for a person. Then, the model calculates the TEE under two scenarios, and we find that the estimation errors are 13.2% and 12.3%.
关键词： total energy expenditure,regression model,Human activity monitoring,micro-Doppler,indirect calorimetry
更新于2025-09-23 15:19:57