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排序方式: 共有524条查询结果,搜索用时 15 毫秒
71.
par Leïla Dogguy-Smiri Nguyen-Huy Dung Marie-Paule Pardo 《Materials Research Bulletin》1978,13(7):661-666
Twins of were used for crystal structure determination. Twinning is explained by a reticular pseudomerihedry. Axis, plane and obliquity of the twin have been determined. Cell dimensions are: ; ; α = β = γ = 90°; space group 14; Z = 2. The final R value is 0.059. The material is isostructural with CdGa2S4. 相似文献
72.
Walter Kutschera Peter J. Billquist Dieter Frekers Walter Henning Kenneth J. Jensen Ma Xiuzeng Richard Pardo Michael Paul Karl E. Rehm Robert K. Smither Jan L. Yntema Leonard F. Mausner 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》1984,5(2):430-435
The half-life of 60Fe has been measured to be a, significantly longer than the one previous measurement of Roy and Kohman which reported a value of 3 × 105 a uncertain by a factor of 3. The present value was obtained from measurements of specific activity and radioisotope concentration in a material produced by spallation of copper with 191 MeV protons. 60Fe/Fe ratios in the range of 10?8 were measured with the Argonne FN tandem-superconducting linear accelerator system in conjunction with an Enge split-pole spectrograph. The specific activity of 60Fe in Fe was measured through the grow-in of the 1.332 MeV gamma-ray line of the 60Co daughter activity. 相似文献
73.
74.
Prediction of weld pool and reinforcement dimensions of GMA welds using a finite-element model 总被引:5,自引:0,他引:5
Mathematical models of the gas metal arc (GMA) welding process may be used to study the influence of various welding parameters
on weld dimensions, to assist in the development of welding procedures, and to aid in the generation of process control algorithms
for automated applications. In this work, a three-dimensional (3-D), steady-state thermal model of the GMA welding process
has been formulated for a moving coordinate framework and solved using the finite-element method. The model includes temperature-dependent
material properties, a new finite-element formulation for the inclusion of latent heat of fusion, a Gaussian distribution
of heat flux from the arc, plus the effects of mass convection into the weld pool from the melted filler wire. The influence
of weld pool convection on the pool shape was approximated using anisotropically enhanced thermal conductivity for the liquid
phase. Weld bead width and reinforcement height were predicted using a unique iterative technique developed for this purpose.
In this paper, the numerical model is shown to be capable of predicting GMA weld dimensions for individual welds, including
those with finger penetration. Also, good agreement is demonstrated between predicted weld dimensions and experimentally derived
relations that describe the effects of process variables and their influence on average weld dimensions for bead-onplate GMA
welds on steel plate.
E. PARDO, formerly Postdoctoral Fellow, Department of Mechanical Engineering, University of Waterloo, Waterloo, ON, Canada
N2L 3G1, 相似文献
75.
Marìe-Paule Pardo Leïla Dogguy-Smiri Jean Flahaut Nguyen Huy Dung 《Materials Research Bulletin》1981,16(11):1375-1384
The system was studied by DTA, X-ray diffraction and in particular by the Guinier-Lenné method. Eight intermediate phases are described. 1) Three solid solutions in the Ga2S3 region : a) a wurtzite-type solid solution (T > 1000° C ; 0.05 < n < 0.23) (n = Fe at+Ga at), b) a blende-type solid solution (700°C < T < 980°C ; 0.10 < n < 0.20) with many stacking faults, c) a non-stoichiometric hexagonal phase α'Ga2S3 type (T < 700°C, 0.07 < n < 0.12). 2) for n = 0.20 and T = 540°C a superstructure of orthorhombic wurtzite-like array FeGa4S7. 3) From n = 0.20 through n = 0.27, a non stoichiometric superstructure of tetragonal-like array has the CdGa2S4 type (600°C < T < 1030°C). 4) For n = 0.33, the FeGa2S4 has two forms depending from the temperature : a) a low temperature form is trigonal ; b) a high temperature form is orthorhombic type ZnAl2S4. Transition temperature is 1010°C. 5) For n = 0.50, Fe2Ga2S5 polytypes : a) Fe2Ga2S5α 1T type Mn2Ga2S5 ; b) Fe2Ga2S5 2H ; c) Fe2Ga2S5 3R type Mn2Al2Se5. A phase diagram is proposed. 相似文献
76.
O. Gorochov C. Levy-Clément L. Dogguy-Smiri M.-P. Pardo 《Materials Research Bulletin》1981,16(12):1493-1497
FeGa2S4α 1T shows a lamellar crystal structure characterized by an alternative localization in host sulfur framework of Fe,Ga and vacancies planes parallel to the c axis of the unit cell. Single crystals have been obtained by chemical vapor transport reaction with I2 or Cl2 as transporting agent. Magnetic, mössbauer and electrical experiments were performed on single crystals. Magnetic susceptibility deviates from the Curie-Weiss behaviour in explorated temperature range 4.2–300 K but the high temperature asymptote indicates a probable Fe2+ high spin state. At approximately 17 K susceptibility shows a maximum which is corrolated to an antiferromagnetic ordering at low temperature. Magnetic properties are discussed in the view of a two dimensional model. Electrical properties are in agreement with semiconducting state; mobility of the charge carriers is low. 相似文献
77.
Jose Emilio Pardo Enrique Fernández Manuela Rubio Andrés Alvarruiz Gonzalo Luis Alonso 《European Journal of Lipid Science and Technology》2009,111(2):188-193
In this work, oil obtained from seeds of different red grape varieties, grown in the Autonomous Regions of Castilla‐La Mancha and Murcia (Spain), was characterized by determining physicochemical and sensory quality parameters, stability, and the composition in fatty acids and sterols. The physicochemical quality parameters (free acidity, peroxide index, K270 and wax) scored high (meaning low quality) compared with virgin olive oils, while the negative sensory attributes stood out over the positive ones. Therefore, the oil was not considered suitable for table use without undergoing a refining process. The samples showed high linoleic and low linolenic acid contents, while β‐sitosterol was the main sterol found. Drying grape seeds with hot air before extraction gave higher physicochemical quality, total phenolic content and stability, and lower wax content in comparison to air‐drying of seeds. The drying process affected the sterol composition but not the fatty acid composition. 相似文献
78.
Cándida Lorenzo Francisco Pardo Amaya Zalacain Gonzalo L. Alonso M. Rosario Salinas 《European Food Research and Technology》2008,227(3):777-787
Co-winemaked Monastrell wines with Cabernet Sauvignon or Merlot, at different proportions have been studied for first time
in terms of its odor activity value (OAV) in young wines, aging wines (after 9 months in French oak barrels) and bottled aging
wines (aging wines after 6 months in the bottle). The co-winemaking wines showed a different aromatic complexity as they were
fruitier and sweeter than the monovarietal ones, enhancing their aroma characteristics, being more evident at 60:40 proportion
in case of Merlot for young and aging wines and Cabernet Sauvignon for bottled ones. In terms of extractable oak compounds,
Monastrell–Merlot wines showed the highest values suggesting that they may need a shorter period within the barrel than Monastrell–Cabernet
Sauvignon ones. 相似文献
79.
Ignacio Brevis Ángel Rodríguez-Rozas Jaime H. Ortega David Pardo 《Computers & Mathematics with Applications》2019,77(5):1358-1375
We study the problem of source reconstruction for a linear elasticity problem applied to seismicity induced by mining. We assume the source is written as a variable separable function . We first present a simple proof a local decay result for elasticity in the case of homogeneous media. We then extend the source time reversal method, originally developed for acoustic waves, to an elastic system of waves. Additionally, we present a fast reconstruction implementation for large data sets. This is especially useful in the elastic case, in which the numerical cost is higher than in fluid acoustics. We complement this work with several 2D and 3D numerical experiments and an analysis of the results. 相似文献
80.
Kondrashev S Dickerson C Levand A Ostroumov PN Pardo RC Savard G Vondrasek R Alessi J Beebe E Pikin A Kuznetsov GI Batazova MA 《The Review of scientific instruments》2012,83(2):02A902
Recently, the Californium Rare Isotope Breeder Upgrade (CARIBU) to the Argonne Tandem Linac Accelerator System (ATLAS) was commissioned and became available for production of rare isotopes. Currently, an electron cyclotron resonance ion source is used as a charge breeder for CARIBU beams. To further increase the intensity and improve the purity of neutron-rich ion beams accelerated by ATLAS, we are developing a high-efficiency charge breeder for CARIBU based on an electron beam ion source (EBIS). The CARIBU EBIS charge breeder will utilize the state-of-the-art EBIS technology recently developed at Brookhaven National Laboratory (BNL). The electron beam current density in the CARIBU EBIS trap will be significantly higher than that in existing operational charge-state breeders based on the EBIS concept. The design of the CARIBU EBIS charge breeder is nearly complete. Long-lead components of the EBIS such as a 6-T superconducting solenoid and an electron gun have been ordered with the delivery schedule in the fall of 2011. Measurements of expected breeding efficiency using the BNL Test EBIS have been performed using a Cs(+) surface ionization ion source for external injection in pulsed mode. In these experiments we have achieved ~70% injection∕extraction efficiency and breeding efficiency into the most abundant charge state of ~17%. 相似文献