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排序方式: 共有1181条查询结果,搜索用时 187 毫秒
31.
Raymond Brennan Carli Moorehead Victoria Blair Krista Limmer 《Materials and Manufacturing Processes》2018,33(1):93-98
Energy coupled to matter (ECM) concepts such as magnetic field–assisted processing were used to align rare earth–doped alumina ceramics in the presence of applied fields. The addition of gadolinium and ytterbium dopants to alumina increased the magnetic susceptibility anisotropies, and induced magnetic torques that led to significant alignment of ceramic particles under the application of magnetic fields as low as 1.8?T. In comparison, undoped alumina materials showed minimal alignment under applied field strengths as high as 9?T. Density function theory modeling indicated that the specific dopant type dictated changes in the magnetic properties of different rare earth–doped alumina systems by directly affecting the magnetic moment localization and magnetocrystalline anisotropy. 相似文献
32.
IS Balakhovski? 《Canadian Metallurgical Quarterly》1998,(5):33-38
Traditionally, the term "precision" denotes the quality of work, uniting the correctness and reproducibility of results. However, it can have another sense: the minimal difference between the specimens, detectable by this or that device or method. In order to rule out misunderstanding, we propose to use the term "measuring precision", if the term is used in its second meaning. It is easy to assess the measuring precision by statistical processing of large scope of data: if the histogram shows waves which disappear after the histogram step is increased, this means that the device and method used in this study permit biochemical analysis only at measuring precision corresponding to the histogram step at which the waves disappear. A table of measuring precision values is offered for 19 methods realized using the Labsystems FP-900 device (Finland) In many cases it is obviously low. 相似文献
33.
Barrett CP Blair P Buller GS Neilson DT Robertson B Smith EC Taghizadeh MR Walker AC 《Applied optics》1996,35(35):6934-6944
We describe an optical system developed to form the basis of a 64 × 64 free-space optical matrix-matrix crossbar switch. The design and performance of each of the main optical components is discussed: lenses, diffractive optical elements, and polarizing beamsplitters, together with the optomechanical hardware design. For these components, throughput levels of -6.9 dB have been achieved, which is compatible with full system operation at 10(-12) bit error rates at ≥270 Mbits s(-1). 相似文献
34.
JD Reveille GS Alarcón SE Fowler SR Pillemer R Neuner DO Clegg IS Mikhail DE Trentham JC Leisen G Bluhm SM Cooper H Duncan M Tuttleman SP Heyse JT Sharp B Tilley 《Canadian Metallurgical Quarterly》1996,39(11):1802-1807
OBJECTIVE: To examine the effect of alleles encoding the "shared"/"rheumatoid" epitope on rheumatoid arthritis (RA) disease severity in patients who participated in the minocycline in RA (MIRA) trial. METHODS: Of 205 patients with a week-48 visit, blood was available for typing of HLA-DRB1 and HLA-DQB1 in 174 (85%) and successfully completed in 169 (82%). Baseline erosions were used to assess disease severity and new erosions at the last visit served as a proxy for progression. RESULTS: At baseline, there was no association between the presence of erosive disease or rheumatoid factor status and the dose of rheumatoid epitope (homozygous, heterozygous, none) or the specific alleles identified. At the final visit, a gradient was observed for the 3 allelic subgroups (and their gene doses) in the occurrence of new erosions among the Caucasian placebo-treated, but not the minocycline-treated, patients. A treatment group/HLA-DR4 epitope interaction was demonstrated in multivariate analyses. Approximately two-thirds of African-American patients did not have the rheumatoid epitope. CONCLUSION: HLA-DRB1 oligotyping may be useful in predicting the progression of disease in some Caucasian patients. Our study corroborates the infrequency of the epitope among African-American patients with RA. 相似文献
35.
Models@ run.time 总被引:2,自引:0,他引:2
Runtime adaptation mechanisms that leverage software models extend the applicability of model-driven engineering techniques to the runtime environment. Contemporary mission-critical software systems are often expected to safely adapt to changes in their execution environment. Given the critical roles these systems play, it is often inconvenient to take them offline to adapt their functionality. Consequently, these systems are required, when feasible, to adapt their behavior at runtime with little or no human intervention. A promising approach to managing complexity in runtime environments is to develop adaptation mechanisms that leverage software models, referred to as models@run. time. Work on models@run.time seeks to extend the applicability of models produced in model-driven engineering (MDE) approaches to the runtime environment. Models@run. time is a causally connected self-representation of the associated system that emphasizes the structure, behavior, or goals of the system from a problem space perspective. 相似文献
36.
37.
Charles Weir Ingolf Becker James Noble Lynne Blair M. Angela Sasse Awais Rashid 《Software》2020,50(3):275-298
Though some software development teams are highly effective at delivering security, others either do not care or do not have access to security experts to teach them how. Unfortunately, these latter teams are still responsible for the security of the systems they build: systems that are ever more important to ever more people. We propose that a series of lightweight interventions, six hours of facilitated workshops delivered over three months, can improve a team's motivation to consider security and awareness of assurance techniques, changing its security culture even when no security experts are involved. The interventions were developed after an Appreciative Inquiry and Grounded Theory survey of security professionals to find out what approaches work best. We tested the interventions in a participatory action research field study where we delivered the workshops to three software development organizations and evaluated their effectiveness through interviews beforehand, immediately afterwards, and after twelve months. We found that the interventions can be effective with teams with limited or no security experience and that improvement is long-lasting. This approach and the learning points arising from the work here have the potential to be applied in many development teams, improving the security of software worldwide. 相似文献
38.
Thomas R. Bieler Bite Zhou Lauren Blair Amir Zamiri Payam Darbandi Farhang Pourboghrat Tae-Kyu Lee Kuo-Chuan Liu 《Journal of Electronic Materials》2012,41(2):283-301
Because failures in lead-free solder joints occur at locations other than the most highly shear-strained regions, reliability
prediction is challenging. To gain physical understanding of this phenomenon, physically based understanding of how elastic
and plastic deformation anisotropy affect microstructural evolution during thermomechanical cycling is necessary. Upon solidification,
SAC305 (Sn-3.0Ag-0.5Cu) solder joints are usually single or tricrystals. The evolution of microstructures and properties is
characterized statistically using optical and orientation imaging microscopy. In situ synchrotron x-ray measurements during thermal cycling are used to examine how crystal orientation and thermal cycling history
change strain history. Extensive characterization of a low-stress plastic ball grid array (PBGA) package design at different
stages of cycling history is compared with preliminary experiments using higher-stress package designs. With time and thermal
history, microstructural evolution occurs mostly from continuous recrystallization and particle coarsening that is unique
to each joint, because of the specific interaction between local thermal and displacement boundary conditions and the strong
anisotropic elastic, plastic, expansion, and diffusional properties of Sn crystals. The rate of development of recrystallized
microstructures is a strong function of strain and aging. Cracks form at recrystallized (random) boundaries, and then percolate
through recrystallized regions. Complications arising from electromigration and corrosion are also considered. 相似文献
39.
I.P.L. Coleman J.A. Blair M.E. Hilburn 《The International journal of environmental studies》2013,70(3-4):187-191
The effect of a number of dietary and synthetic chelating agents on the intestinal absorption of lead has been examined using the everted sac preparation and the tracer isotope 203Pb. All the agents examined increased lead transport into the serosal compartment. An explanation of the way in which these agents modify the model to describe lead transport is proposed. 相似文献
40.
Dr. Liam J. Stephens Dr. Aviva Levina Dr. Iman Trinh Dr. Victoria L. Blair Dr. Melissa V. Werrett Prof. Peter A. Lay Prof. Philip C. Andrews 《Chembiochem : a European journal of chemical biology》2020,21(8):1188-1200
RuII-arene complexes provide a versatile scaffold for novel anticancer drugs. Seven new RuII-arene-thiocarboxylato dimers were synthesized and characterized. Three of the complexes ( 2 a , b and 5 ) showed promising antiproliferative activities in MDA-MB-231 (human invasive breast cancer) cells, and were further tested in a panel of fifteen cancerous and noncancerous cell lines. Complex 5 showed moderate but remarkably selective activity in MDA-MB-231 cells (IC50=39±4 μm Ru). Real-time proliferation studies showed that 5 induced apoptosis in MDA-MB-231 cells but had no effect in A549 (human lung cancer, epithelial) cells. By contrast, 2 a and b showed moderate antiproliferative activity, but no apoptosis, in either cell line. Selective cytotoxicity of 5 in aggressive, mesenchymal-like MDA-MB-231 cells over many common epithelial cancer cell lines (including noninvasive breast cancer MCF-7) makes it an attractive lead compound for the development of specifically antimetastatic Ru complexes with low systemic toxicity. 相似文献