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71.
Yixing Tian Huiling Liu Brian W.Sheldon Thomas J.Webster Sichen Yang Huilin Yang Lei Yang 《材料科学技术学报》2019,35(5):817-823
Nanostructured diamond have potential applications in many biomedical related fields and demonstrated extraordinary capacity to influence cellular responses. Studying the surface property of nanodiamond and its influence to protein adsorption and subsequent cellular responses along with the mechanism behind such capacity becomes more important. Here the role of surface energy associated with nanostructured diamond in modulating fibronectin and osteoblast(OB, bone forming cells) responses was investigated. Nanocrystalline diamond(NCD) and submicron crystalline diamond(SMCD) films with controllable surface energy were prepared by microwave-enhanced plasma chemical vapor deposition(MPCVD) techniques. Fibronectin adsorption on the diamond films with varied surface energy values was measured via the enzyme-linked immunosorbent assay(ELISA) and the relationship between the surface energy and fibronectin adsorption was studied. The result indicated that fibronectin adsorption on nanostructured surfaces was closely related to both surface energy and material microstructures. The spreading and migration of OB aggregates(each containing 30–50 cells) on the NCD with varied surface energy values were also studied. The result indicates a correlation between the cell spreading and migration on nanodiamond and the surface energy of nanostructured surface. 相似文献
72.
73.
Wang B Summa B Pascucci V Vejdemo-Johansson M 《IEEE transactions on visualization and computer graphics》2011,17(12):1902-1911
Large observations and simulations in scientific research give rise to high-dimensional data sets that present many challenges and opportunities in data analysis and visualization. Researchers in application domains such as engineering, computational biology, climate study, imaging and motion capture are faced with the problem of how to discover compact representations of high-dimensional data while preserving their intrinsic structure. In many applications, the original data is projected onto low-dimensional space via dimensionality reduction techniques prior to modeling. One problem with this approach is that the projection step in the process can fail to preserve structure in the data that is only apparent in high dimensions. Conversely, such techniques may create structural illusions in the projection, implying structure not present in the original high-dimensional data. Our solution is to utilize topological techniques to recover important structures in high-dimensional data that contains non-trivial topology. Specifically, we are interested in high-dimensional branching structures. We construct local circle-valued coordinate functions to represent such features. Subsequently, we perform dimensionality reduction on the data while ensuring such structures are visually preserved. Additionally, we study the effects of global circular structures on visualizations. Our results reveal never-before-seen structures on real-world data sets from a variety of applications. 相似文献
74.
In this paper, we propose a reversible data hiding method for ordered dithered halftone images. To achieve reversibility and high capacity, the proposed method decomposes an ordered dithered halftone into a maximal number of subimage pairs with the same characteristic, and then hides data with a subimage-swapping operation, which converts a subimage pair into a subimage pair with opposite characteristic. Besides, this method maintains good visual quality by exchanging neighboring pixels instead of flipping individual pixels. Experimental results show that this method has the highest capacity among the existing reversible data hiding methods. A reversible authentication watermarking system is also proposed using this reversible watermarking method and it shows better visual quality compared to an existing method. 相似文献
75.
76.
Smoke animations are hard to art‐direct because simple changes in parameters such as simulation resolution often lead to unpredictable changes in the final result. Previous work has addressed this problem with a guiding approach which couples low‐resolution simulations – that exhibit the desired flow and behaviour – to the final, high‐resolution simulation. This is done in such a way that the desired low frequency features are to some extent preserved in the high‐resolution simulation. However, the steady (i.e. constant) guiding used often leads to a lack of sufficiently high detail, and employing time‐dependent guiding is expensive because the matrix of the resulting set of equations needs to be recomputed at every iteration. We propose an improved mathematical model for Eulerian‐based simulations which is better suited for dynamic, time‐dependent guiding of smoke animations through a novel variational coupling of the low‐ and high‐resolution simulations. Our model results in a matrix that does not require re‐computation when the guiding changes over time, and hence we can employ time‐dependent guiding more efficiently both in terms of storage and computational requirements. We demonstrate that time‐dependent guiding allows for more high frequency detail to develop without losing correspondence to the low resolution simulation. Furthermore, we explore various artistic effects made possible by time‐dependent guiding. 相似文献
77.
The University of Sussex In-School Teacher Education Project (InSTEP) uses interactive video technologies to enhance initial teacher education programmes for science trainee teachers. With four Internet Protocol cameras and mounted microphones in both school laboratories and the university teaching room, trainees and their tutors have access to live interaction with schools. This paper presents some of the findings of a 2 year evaluation of InSTEP aimed at identifying the benefits for trainee teachers. There has been an increase in the use of video material for teacher training purposes, however, trainee teachers are often intimidated by carefully selected extracts featuring experienced teachers. InSTEP activities are live and capitalise on all the opportunities associated with normal classroom practice. Literature points to InSTEP-type activities having the potential to enhance the development of trainees’ observation skills, develop reflective thinking, to provide authentic illustrations of classroom practice, enable remote observation and facilitate the coaching of trainees by mentors. A fourth generation model of evaluation was undertaken with data generated by semi-structured interviews with university tutors and mentors supported by a questionnaire and group interviews with the trainees. Our main findings point to InSTEP enhancing and accelerating the growth of trainee teachers’ professional knowledge through enabling reflective practice, facilitating collaborative learning and supporting the development of the language of pedagogy. 相似文献
78.
Weiya Jin Brian H. Dennis Bo Ping Wang 《Structural and Multidisciplinary Optimization》2010,41(3):433-439
The semi-analytical method (SAM) is a computationally efficient and easy to implement approach often used for the sensitivity
analysis of finite element models. However, it is known to exhibit serious inaccuracy for shape sensitivity analysis for structures
modeled by beam, frame, plate, or shell elements. In the present paper, we use a semi-analytical approach based on complex
variables (SACVM) to compute the sensitivity of finite element models composed of beam and plate elements. The SACVM combines
the complex variable method (CVM) with the semi-analytical method (SAM) to obtain the response sensitivity accurately and
efficiently. The current approach maintains the computational efficiency of the semi-analytical method but with higher accuracy.
In addition, the current approach is insensitive to the choice of step size, a feature that simplifies its use in practical
problems. The method is applicable to any structural elements including beam, frame, plate, or shell elements and only requires
minor modifications to existing finite element codes. 相似文献
79.
Srinivasulu?Malagari Brian?J.?DriessenEmail author 《Journal of Intelligent and Robotic Systems》2011,62(1):29-58
In this work, we consider a multiple degree of freedom robotic plant with joint hysteresis and without velocity measurement.
We show, by construction, how a semi-globally exponential hysteresis observer/controller that assumes velocity measurement,
a number of which we point out from the literature, can be combined/modified with a velocity observer to yield a combined
semi-globally exponential tracking observer/controller. The resulting observer/controller estimates both the hysteresis state
and the joint velocity. We prove that the combined estimation error and tracking error converges to zero semi-globally exponentially.
One deemed contribution as compared to previous work for this same type of plant is that the usual requirement of velocity
measurement has been removed; another is the proved semi-globally exponential result. 相似文献
80.
Brian A. EnglishAuthor Vitae Mark G. AllenAuthor Vitae 《Sensors and actuators. A, Physical》2011,172(2):483-490
The presented work studied thermal interactions between laminated, metal-foil, hot-wire igniters and exothermic solid-state, composite chemical systems in order to demonstrate precise timing control of a thermal ignition process. The study includes FEA modeling, device fabrication, and characterization to demonstrate control microthruster ignition delays to within 2 ms. The modeling included studies of total ignition delay as well as the ignition delay variation versus process variations. Microthrusters were then fabricated via printed circuit board lamination, and the ignition performance was characterized. The characterization showed agreement with modeling to within 2-sigma for most cases. And the characterization demonstrated that the ignition delay could be controlled to within 0.36 and 0.84 ms for the best case. Furthermore, this performance was demonstrated with a small battery supply (200-600 mAh) and minimal electronics in the ignition system. This work extends the use of current microthrusters to short-lifetime applications that need high forces delivered in millisecond time intervals. 相似文献