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971.
Oxide dispersion strengthened nickel (ODS-Ni) electrodeposits were fabricated to net shape using the lithography, electroforming, and molding (LIGA) process in a nickel sulfamate bath containing a suspension of 10 nm diameter Al2O3 particulates. Mechanical properties were compared to baseline specimens fabricated using an identical sulfamate bath chemistry without the particulates. Results revealed that the as-deposited ODS-Ni exhibited significantly higher yield strength and ultimate tensile strength (∼50 pct) than the baseline material. This increase in as-deposited strength was attributed to Orowan strengthening. The ODS-Ni also showed improved retention of room-temperature strength after annealing over a range of temperatures up to 600 °C. Nanoindentation measurements revealed that the properties of the dispersion-strengthened deposit were uniform through its thickness, even in narrow, high aspect ratio structures. Microscopy revealed that this resistance to anneal softening was due to an inhibition of grain growth in the presence of the oxide dispersion. At elevated temperatures, the strength of the ODS-Ni was approximately 3 times greater than that of the baseline material although with a significant reduction in hot ductility.  相似文献   
972.
Mutilated chessboard problem is exponentially hard for resolution   总被引:1,自引:0,他引:1  
Mutilated chessboard principle CBn says that it is impossible to cover by domino tiles the chessboard 2n×2n with two diagonally opposite corners removed. We prove lower bound on the size of minimal resolution refutation of CBn.  相似文献   
973.
974.
We have developed an easy-to-use and cost-effective system to construct textured 3D animated face models from videos with minimal user interaction. This is a particularly challenging task for faces due to a lack of prominent textures. We develop a robust system by following a model-based approach: we make full use of generic knowledge of faces in head motion determination, head tracking, model fitting, and multiple-view bundle adjustment. Our system first takes, with an ordinary video camera, images of a face of a person sitting in front of the camera turning their head from one side to the other. After five manual clicks on two images to indicate the position of the eye corners, nose tip and mouth corners, the system automatically generates a realistic looking 3D human head model that can be animated immediately (different poses, facial expressions and talking). A user, with a PC and a video camera, can use our system to generate his/her face model in a few minutes. The face model can then be imported in his/her favorite game, and the user sees themselves and their friends take part in the game they are playing. We have demonstrated the system on a laptop computer live at many events, and constructed face models for hundreds of people. It works robustly under various environment settings.  相似文献   
975.
According to C. L. Dym and P. Little, the complete design process includes identifying a need or problem, recognizing constraints, identifying and developing courses of action, testing potential courses of action, selecting optimum courses of action, preparing the documents required for the design, managing the overall process, communicating the design, construction, and testing. We have addressed these design considerations by linking design projects in our introductory physicochemical treatment processes course (EV401, taken by second-semester juniors) and our senior capstone design course (EV490, taken by second-semester seniors). The process developed and implemented addresses the integration of professional practice into design inexperience. We require our cadet students to communicate with their customers, an illustrator, and tradesmen, three forms of communication that are necessarily quite different from traditional student-professor exchanges. Also, students must design under constraints, this time not because of the closed nature of the project but rather because of “real world” resource constraints: time to complete the project, a limited budget to purchase materials and labor, availability of materials, ease of construction, and balancing competing projects (in other courses). The first attempt at implementing this engineering design learning model occurred during the spring of 2001 in EV401. Herein we assess the design and construction of one of two projects, oriented toward modification of a surface-water treatment plant model. Results suggest that iterative growth can occur and a more complete appreciation of the design process can result.  相似文献   
976.
Ratings of patient efficacy to manage illness, made by 191 congestive heart failure patients and their spouses, were examined as predictors of patients' survival over the next 4 years. When considered alone, both the patient's self-efficacy and the spouse's confidence ratings predicted survival, but only spouse confidence remained significant when both partners" efficacy ratings were included in the same Cox regression model. The overlapping prognostic significance of spouse confidence and a global, multicomponent measure of marital quality positioned the former as a proxy for the latter, reflecting a fundamentally social protective factor in patient survival. Successful adaptation to heart failure appears to involve more than the patient's personal agency, and psychosocial data from spouses can improve prediction of patient outcomes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
977.
Cancer patients experience positive as well as adverse consequences from diagnosis and treatment. The study reported here examined longer term reverberations of such experiences. A set of benefit-finding items along with measures of well-being were completed by 230 early-stage breast cancer patients in the year postsurgery. Four to 7 years later, 96 of them again completed measures of well-being. Controlling for initial distress and depression, initial benefit finding in this sample predicted lower distress and depression at follow-up. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
978.
To identify the psychological impact of receipt of an abnormal yet benign screening test result, the authors examined the response to a transvaginal ultrasound screening (TVS) test for ovarian cancer (OC) in asymptomatic women (N=540) undergoing an initial TVS screening test. Interviews were conducted prior to undergoing TVS screening and at 2 weeks and 4 months following this baseline. Women receiving an abnormal yet benign TVS test result (n=33) reported elevated OC-specific, but not general, distress at 2-week follow-up. Distress returned to baseline levels at 4-month follow-up. Consistent with the monitoring process and cognitive-social health information processing models, response to an abnormal TVS result was moderated by a monitoring coping style, low optimism, and a family history of OC. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
979.
Significant insight into the response of granular materials can be gained by coupling accurately controlled physical tests with complementary discrete element simulations. This paper discusses a series of triaxial and plane strain laboratory compression tests on steel spheres with face-centered-cubic and rhombic packings, as well as discrete element simulations of these tests. The tests were performed on specimens of uniform-sized steel balls and on specimens of steel balls with specified distributions of ball diameters. The packing configurations are ideal and differ considerably from real sand specimens, however, studies of such idealized granular materials can yield considerable insight into the response of granular materials and the capability of discrete element simulations to capture the response. The differences in response for the two packing configurations considered illustrate the importance of fabric. The numerical simulations captured the observed laboratory response well if the particle configurations, particle sizes, and boundary conditions were accurately represented. However, the postpeak response is more difficult to capture, and it is shown to be sensitive to the coefficient of friction assumed along the specimen boundaries. The simulations of the tests on the nonuniform-sized specimens demonstrated a clear correlation between strength and coordination number.  相似文献   
980.
The authors developed and tested the prediction that the relationship hetween coworkers' organizational citizenship behaviors (OCBs) and fellow employees' attitudes depends on the supervisors' abusiveness. Results of a longitudinal study using data collected from 173 supervised employees at 2 points in time (separated by 7 months) suggested that coworkers' OCB was positively related to fellow employees' job satisfaction and affective commitment when abusive supervision was low. However, when abusive supervision was high, coworkers' OCB was negatively related to job satisfaction and was unrelated to organizational commitment. The results of a 2nd study were consistent with the idea that the attributions employees make for their coworkers' OCB explains the moderating effect of abusive supervision on the relationship between coworkers' OCB and job satisfaction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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