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排序方式: 共有520条查询结果,搜索用时 15 毫秒
81.
Annabel Braem Tina Mattheys Bram Neirinck Miran Čeh Saša Novak Jan Schrooten Omer Van der Biest Jef Vleugels 《Materials science & engineering. C, Materials for biological applications》2012,32(8):2267-2273
Surface modification of Ti alloys towards an improved osteoinductive behaviour is one of the major challenges in orthopaedic implant technology nowadays. One way to achieve this is by applying a bioactive coating which can increase the rate of osseointegration and chemical bonding of surrounding bone to the implant. In the present work, the production of a bioactive glass–ceramic coating on flat Ti alloys by electrophoretic deposition is demonstrated. The coatings are applied by cathodic deposition from non-aqueous suspensions followed by sintering in vacuum, avoiding uncontrolled oxidation of the Ti substrates. The use of non-aqueous suspensions both allowed to reduce the deposition time and yielded homogeneous coatings with a uniform thickness of 8 μm. Evaluation of the coating adhesion confirmed the good mechanical performance of the coatings with a tensile bond strength of 41.0 ± 11.1 MPa. Additionally, a feasibility study demonstrated the potential of electrophoretic deposition as a coating technique for commercial complex implants. 相似文献
82.
Accumulative roll bonding (ARB) as a method of severe plastic deformation is a well-established process to produce ultrafine-grained
(UFG) sheet materials with extraordinary mechanical properties. In this work ARB is applied to combine different sheet materials
in order to tailor the materials properties by producing sandwich-like structures. The high strength aluminium alloy AA5754,
after 4 ARB cycles (N4), is used as a core material. To achieve high corrosion resistance and good visual properties, it is
cladded with commercially pure aluminium AA1050A (N4) at room temperature and alternatively with AA6014 (N4) at 230 °C. All
materials are UFG and satisfactory bonding between the different layers of aluminium alloys is achieved. Nanoindentation measurements
reveal that there is a sharp transition in hardness at the interface. The yield and tensile strength of the core material
are fully retained in the case of the AA6014/AA5754 sandwich. The strength of the AA1050A/AA5754 sandwich is slightly lower
compared to the core material but still twice as high as the clad material. The serrated yielding effect which is strongly
visible in tensile tests on the pure AA5754 alloy completely disappears in the sandwich sheets, which means the surface quality
is strongly enhanced. 相似文献
83.
84.
Du Rocher Schudlich Tina D.; Papp Lauren M.; Cummings E. Mark 《Canadian Metallurgical Quarterly》2011,25(4):531
This study investigated longitudinal relations between spouses' depressive symptoms and styles of conflict resolution displayed by husbands and wives in marital conflict, including angry, depressive, and constructive patterns of expression. Behavioral observations were made from a community sample of 276 couples during marital conflict resolution tasks once a year for 3 years. Couples were observed engaging in a major and minor conflict resolution task. Constructive, angry, and depressive conflict resolution styles were derived from the behavioral observation coding. Couples self-reported on depressive symptoms and marital dissatisfaction. Path analyses provided support for an extension of the marital discord model of depression (Beach, Sandeen, & O'Leary, 1990). Specifically, angry, depressive, and constructive styles of conflict each mediated the link between marital dissatisfaction and depressive symptoms. Significant cross-spouse effects were found. Implications for the treatment of depressed and/or relationally discordant couples are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
85.
Headquarters’ Attention and Its Effect on Subsidiary Performance 总被引:2,自引:0,他引:2
• |
Drawing on a sample of 283 subsidiaries in three countries, we investigate how headquarters’ attention affects subsidiary
performance. 相似文献
86.
Jennifer Neville Brian Gallagher Tina Eliassi-Rad Tao Wang 《Knowledge and Information Systems》2012,30(1):31-55
Recently, a number of modeling techniques have been developed for data mining and machine learning in relational and network domains where the instances are not independent and identically distributed (i.i.d.). These methods specifically exploit the statistical dependencies among instances in order to improve classification accuracy. However, there has been little focus on how these same dependencies affect our ability to draw accurate conclusions about the performance of the models. More specifically, the complex link structure and attribute dependencies in relational data violate the assumptions of many conventional statistical tests and make it difficult to use these tests to assess the models in an unbiased manner. In this work, we examine the task of within-network classification and the question of whether two algorithms will learn models that will result in significantly different levels of performance. We show that the commonly used form of evaluation (paired t-test on overlapping network samples) can result in an unacceptable level of Type I error. Furthermore, we show that Type I error increases as (1) the correlation among instances increases and (2) the size of the evaluation set increases (i.e., the proportion of labeled nodes in the network decreases). We propose a method for network cross-validation that combined with paired t-tests produces more acceptable levels of Type I error while still providing reasonable levels of statistical power (i.e., 1−Type II error). 相似文献
87.
In this research, the effect of carbon dioxide laser irradiation on various properties of raw and bleached cotton fabrics, including fabric weight, bending rigidity, wetting, and air permeability, as well as dyeing, was examined and compared. The experiments were carried out at three different laser powers ranging from 4.5 to 6 W to determine the effect of laser treatment on fabric properties. In particular, the influence of laser irradiation on the dyeing properties of treated fabrics with CI Reactive Blue 198 was studied. The colour change of laser‐treated fabrics was determined by calculation of the K/S values as a function of fabric reflectance. The morphological changes in laser‐treated fabrics were observed by scanning electron microscopy. The effects of laser treatment on the properties of raw and bleached cotton fabrics were varied. For instance, the wettability of raw cotton samples was reduced after laser irradiation, whereas the wettability of bleached cotton fabrics was greater. Possible reasons for the various dyeing behaviours observed with irradiation at different laser powers are discussed. 相似文献
88.
Amruta Manke Sudjit Luanpitpong Chenbo Dong Liying Wang Xiaoqing He Lori Battelli Raymond Derk Todd A. Stueckle Dale W. Porter Tina Sager Honglei Gou Cerasela Zoica Dinu Nianqiang Wu Robert R. Mercer Yon Rojanasakul 《International journal of molecular sciences》2014,15(5):7444-7461
Given their extremely small size and light weight, carbon nanotubes (CNTs) can be readily inhaled by human lungs resulting in increased rates of pulmonary disorders, particularly fibrosis. Although the fibrogenic potential of CNTs is well established, there is a lack of consensus regarding the contribution of physicochemical attributes of CNTs on the underlying fibrotic outcome. We designed an experimentally validated in vitro fibroblast culture model aimed at investigating the effect of fiber length on single-walled CNT (SWCNT)-induced pulmonary fibrosis. The fibrogenic response to short and long SWCNTs was assessed via oxidative stress generation, collagen expression and transforming growth factor-beta (TGF-β) production as potential fibrosis biomarkers. Long SWCNTs were significantly more potent than short SWCNTs in terms of reactive oxygen species (ROS) response, collagen production and TGF-β release. Furthermore, our finding on the length-dependent in vitro fibrogenic response was validated by the in vivo lung fibrosis outcome, thus supporting the predictive value of the in vitro model. Our results also demonstrated the key role of ROS in SWCNT-induced collagen expression and TGF-β activation, indicating the potential mechanisms of length-dependent SWCNT-induced fibrosis. Together, our study provides new evidence for the role of fiber length in SWCNT-induced lung fibrosis and offers a rapid cell-based assay for fibrogenicity testing of nanomaterials with the ability to predict pulmonary fibrogenic response in vivo. 相似文献
89.
Živec Tina Anžur Andreja Verbovšek Timotej 《Bulletin of Engineering Geology and the Environment》2019,78(3):1631-1643
Bulletin of Engineering Geology and the Environment - Terrestrial laser scanning (TLS) was performed in tectonically undisturbed flysch in the Elerji quarry (south-west Slovenia), which represents... 相似文献
90.
Tina Marolt Cebasek Jakob Likar 《土木工程与建筑:英文版》2014,(11):1457-1466
The design procedure is made for a mine shaft where permanent underground facilities are interconnected. The highly faulted grounds were identified using empirical and semi-empirical theories. Furthermore, the behavior types are presented. This paper presents excavation and support methods in such ground conditions and the calculations results show that the installation of the yielding elements have an effect on support elements and prevent shotcrete damage during the curing stage. Different numerical analyses carried out showed that, with the yielding elements installed, the total displacements increase but the final axial force reduces, and therefore, the characteristic compressive strength of shotcrete is not exceeded. The calculation results of ground loads and displacements on the designed support system are presented with a 3D numerical geo-mechanical model adopted for highly faulted ground surrounding deeper complex underground structures. 相似文献
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