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排序方式: 共有595条查询结果,搜索用时 218 毫秒
91.
92.
Bernd M. Linke Thomas Gerber Ansgar Hatscher Ilaria Salvatori Iñigo Aranguren Maribel Arribas 《Metallurgical and Materials Transactions A》2018,49(1):54-65
Based on 22MnB5 hot stamping steel, three model alloys containing 0.5, 0.8, and 1.5 wt pct Si were produced, heat treated by quenching and partitioning (Q&P), and characterized. Aided by DICTRA calculations, the thermal Q&P cycles were designed to fit into industrial hot stamping by keeping partitioning times ≤ 30 seconds. As expected, Si increased the amount of retained austenite (RA) stabilized after final cooling. However, for the intermediate Si alloy the heat treatment exerted a particularly pronounced influence with an RA content three times as high for the one-step process compared to the two-step process. It appeared that 0.8 wt pct Si sufficed to suppress direct cementite formation from within martensite laths but did not sufficiently stabilize carbon-soaked RA at higher temperatures. Tensile and bending tests showed strongly diverging effects of austenite on ductility. Total elongation improved consistently with increasing RA content independently from its carbon content. In contrast, the bending angle was not impacted by high-carbon RA but deteriorated almost linearly with the amount of low-carbon RA. 相似文献
93.
94.
Hyang Lan Eum Dae Keun Hwang Manfred Linke Seung Koo Lee Manuela Zude 《European Food Research and Technology》2009,229(3):427-434
Edible coating may enhance the boundary layer resistance resulting in enhanced shelf life of fruits. Plums (Prunus salicina Lindl. cv. ‘Sapphire’) were treated with coating material based on carbohydrate (Versasheen) with sorbitol as plasticizer
and stored at 20 °C and 85% RH. The influence of coating on the gas transmission rates was estimated using a carrier of 100%
cellulose paper. Coating treatment reduced the transmission rate of CO2, O2, and H2O. Changes in fruit weight, fruit flesh firmness, color parameters (L*, a*, and hue angle), soluble solids content, pH, titratable
acidity, ethylene, CO2, malondialdehyde (MDA), and VIS/NIR fruit reflectance spectrum were recorded in 2-day interval. Edible coating was effective
in delaying the increase of pH and the loss of firmness, titratable acidity, L*, hue angle, and MDA. The incorporation of
sorbitol showed beneficial effects on decreasing the weight loss, CO2, and ethylene exchange. In the room temperature storage period, not only fruit ripening was measurable in the VIS (350–750 nm)
and NIR (750–1,400 nm) wavelength ranges due to the decrease in the fruit chlorophyll absorption but also water loss, respectively.
After 5-day room temperature storage the chlorophyll absorption peak in the spectra was already beyond the detection limit
in all treatments, while after 3-day storage, the coating effect on the spectral intensities was feasible to separate control
from coated plums. 相似文献
95.
Hemantha Kumar Yeddu Vsevolod I. Razumovskiy Annika Borgenstam Pavel A. Korzhavyi Andrei V. Ruban John Ågren 《Acta Materialia》2012,60(19):6508-6517
In the present work a multi-length scale model is developed to study both the athermal and stress-assisted martensitic transformations in a single crystal of 301 type stainless steel. The microstructure evolution is simulated using elastoplastic phase-field simulations in three dimensions. The input data for the simulations is acquired from a combination of computational techniques and experimental works. The driving force for the transformation is calculated by using the CALPHAD technique and the elastic constants of the body-centered cubic phase are calculated by using ab initio method. The other input data is acquired from experimental works. The simulated microstructures resemble a lath-type martensitic microstructure, which is in good agreement with the experimental results obtained for a stainless steel of similar composition. The martensite habit plane predicted by the model is in accordance with experimental results. The Magee effect, i.e. formation of favorable martensite variants depending on the loading conditions, is observed in the simulations. The results also indicate that anisotropic loading conditions give rise to a significant anisotropy in the martensitic microstructure. 相似文献
96.
Gutrath BS Beckmann MF Buchkremer A Eckert T Timper J Leifert A Richtering W Schmitz G Simon U 《Nanotechnology》2012,23(22):225707
Photoacoustic (PA) imaging attracts a great deal of attention as an innovative modality for longitudinal, non-invasive, functional and molecular imaging in oncology. Gold nanoparticles (AuNPs) are identified as superior, NIR-absorbing PA contrast agents for biomedical applications. Until now, no systematic comparison of the optical extinction and PA efficiency of water-soluble AuNPs of various geometries and small sizes has been performed.Here spherical AuNPs with core diameters of 1.0, 1.4 and 11.2?nm, nanorods with longitudinal/transversal elongation of 38/9 and 44/12?nm and hollow nanospheres with outer/inner diameters of 33/19, 57/30, 68/45 and 85/56?nm were synthesized. The diode laser set-up with excitations at 650, 808, 850 and 905?nm allowed us to correlate the molar PA signal intensity with the molar extinction of the respective AuNPs. Deviations were explained by differences in heat transfer from the particle to the medium and, for larger particles, by the scattering of light. The molar PA intensity of 1.0?nm AuNPs was comparable to the commonly used organic dye methylene blue, and rapidly increased with the lateral size of AuNPs. 相似文献
97.
Franz Dietrich Christian Löchte Sabina Jeschke Annika Raatz 《Production Engineering》2012,6(4-5):531-539
This article is concerned with the control of the production of aircraft primary structures made of carbon fibre reinforced plastics. To increase the parallelization of the production, a scenario that implies new design paradigms is discussed. In order to realize this parallelization, mobile production entities work concurrently at the same primary structure of the fuselage. The present article proposes a software architecture for the control of such a production system. It is proposed that components are organized hierarchically. In enhancement to previous proposals, two perspectives of hierarchy are used here: grouping by functionality and grouping by timing context. The core of the architecture is a market-based multi-agent system, where the agents may operate in multiple timing contexts. Such a design yields advantages in terms of fast integration of new functionalities and scale-up of the production system. In brief, this article introduces a top-level control architecture for parallelized production of large reliable CFRP structures in a scalable production system. 相似文献
98.
Xianzu GONG Baonian WAN Jiangang LI Jinping QIAN Erzhong LI Fukun LIU Yanping ZHAO Mao WANG Handong XU A M GAROFALO Annika EKEDAH Siye DING Juan HUANG Ling ZHANG Qing ZANG Haiqing LIU Long ZENG Shiyao LIN Biao SHEN Bin ZHANG Linming SHAO Bjngjia XIAO Jiansheng HU Chundong HU Liqun HU Liang WANG Youwen SUN Guosheng XU Yunfeng LIANG Nong XIANG EAST Team 《等离子体科学和技术》2017,19(3):32001
In the 2016 EAST experimental campaign,a steady-state long-pulse H-mode discharge with an ITER-like tungsten divertor lasting longer than one minute has been obtained using only RF heating and current drive,through an integrated control of the wall conditioning,plasma configuration,divertor heat flux,particle exhaust,impurity management,and effective coupling of multiple RF heating and current drive sources at high injected power.The plasma current (Ip ~ 0.45 MA) was fully-noninductively driven (Vloop < 0.0 V) by a combination of ~2.5 MW LHW,~0.4 MW ECH and ~0.8 MW ICRF.This result demonstrates the progress of physics and technology studies on EAST,and will benefit the physics basis for steady state operation of ITER and CFETR. 相似文献
99.
Humidity-Regulating Trays: Moisture Absorption Kinetics and Applications for Fresh Produce Packaging
Guido Rux Pramod V. Mahajan Manfred Linke Astrid Pant Sven Sängerlaub Oluwafemi J. Caleb Martin Geyer 《Food and Bioprocess Technology》2016,9(4):709-716
For packaged fresh produce, inappropriate high relative humidity (RH) levels and condensation of water vapour cause premature spoilage. Humidity-regulating trays were developed to solve this issue. They were made from a thermoformed multilayer structure: polyethylene (outside)/foamed hygroscopic ionomer (active layer) with 0 or 12 wt% NaCl/hygroscopic ionomer (sealing layer, inside). Moisture absorption kinetics of the humidity-regulating trays with 0 and 12 wt% NaCl (T-0 and T-12, respectively) was investigated under different RH conditions (76, 86, 96 and 100 %) at 13 °C for 16 days. Additional trays containing 7 g of distilled water were closed with a high barrier lidding film, and the headspace RH was continuously monitored as a function of time. As control, a polypropylene (control-PP) tray was used. Strawberries and tomatoes were used to test capability of the trays to regulate in-package RH. The amount of water absorbed by the T-0 and T-12 trays was 7.6 and 13.2 g, respectively. Active hygroscopic ionomer layer was effective in water vapour absorption, and the integration of NaCl into this active layer increased the water vapour absorption capacity of the tray. The Weibull model adequately described the moisture sorption kinetics of the individual packaging trays as a function of time. The headspace RH of trays covered with a lidding film was found to be 89.8, 99.6 and 100 % in the T-12, T-0 and control-PP trays, respectively. The T-12 trays containing fresh produce best regulated the in-package RH below 97 % and maintained overall quality, but at the expense of slightly higher product weight loss (2–3 wt% for strawberry, 1 wt% for tomatoes) compared to the control-PP trays (0.3–0.6 wt%). 相似文献
100.
Jiaqing Yin Lindsay Leach Mats Hillert Annika Borgenstam 《Metallurgical and Materials Transactions A》2017,48(9):3997-4005
Widmanstätten ferrite and bainitic ferrite are both acicular and their lengthening rate in binary Fe-C alloys and low-alloyed steels under isothermal conditions is studied by searching the literature and through new measurements. As a function of temperature, the lengthening rate can be represented by a common curve for both kinds of acicular ferrite in contrast to the separate C-curves often presented in time-temperature-transformation (TTT) diagrams. The curves for Fe-C alloys with low carbon content show no obvious decrease in rate at low temperatures down to 623 K (350 °C). For alloys with higher carbon content, the expected decrease of rate as a function of temperature below a nose was observed. An attempt to explain the absence of a nose for low carbon contents by an increasing deviation from local equilibrium at high growth rates is presented. This explanation is based on a simple kinetic model, which predicts that the growth rates for Fe-C alloys with less than 0.3 mass pct carbon are high enough at low temperatures to make the carbon pileup, in front of the advancing tip of a ferrite plate, shrink below atomic dimensions, starting at about 600 K (323 °C). 相似文献