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21.
Using a flatbed scanner as a stereoscopic near-field camera   总被引:1,自引:0,他引:1  
It is shown that flatbed scanners are inherently high quality 3D scanners. Currently developed first prototypes have many applications in industry and multimedia. Because of their big depth of focus, they can be used not only for scanning printed paper, but also for scanning small objects. The nonparallel optics also make it possible to create stereoscopic images of small objects with flatbed scanners, as first described elsewhere (R. Schubert, 1998). The author describes the method for doing this. He also shows examples of stereoscopic images made in this way so that you can judge for yourself their quality and particular properties. Finally, he describes possible accessories that will let you use flatbed scanners routinely in a lot of areas, including hobbies and professional applications. Combining dedicated 3D imaging and evaluation software as well as 3D output devices results in a high quality, low cost 3D scanner. Currently work is under way to specify, design, and build the first prototypes  相似文献   
22.
Two or more parties typically establish a business relationship using a contract, but a large gap still exists between the provisions of contracts produced by lawyers and the details of computer security and performance addressed by technologists. Some contractual clauses address legal issues that technology can manage as well - the TrustCoM framework offers a paradigm for automating these clauses as technical operations. If a business relationship forms across a service-oriented architecture, the parties involved often manage their collaboration as a virtual organization (VO). In TrustCoM, agreements are the key means of steering VO collaborations and mitigating the risks inherent in integrating processes and resources across organizational boundaries.  相似文献   
23.
Measurements have been made of the relative superfluid density sp/ and the critical mass current I sc for the onset of dissipation in the superfluid flow of pure 4He and 3He/4He mixtures in the circular cylindrical pores of Nuclepore near the transition, using a double-ended Helmholtz resonator. Pore diameters of 0.03, 0.1, and 0.4 m were studied using 3He mole fractions of 0.0,0.2, and 0.4. For each pore diameter d p and mole fraction x our results for sp / were fitted relatively well by the form C(tt 01)0.675 and those for I sc by the form I sc0(tt 0c ) g , where t [T T]/T . For each combination of d p and x the reduced onset temperatures t 01 and t 0c are in rough agreement with each other but somewhat larger than values found by others for Nuclepore. For the smaller two pore diameters, these onset temperatures are consistent with the universality hypothesis that near T, 2 sb /m 4 2 k B T should be a constant independent of T and x. Here is the reduced Planck constant, sb is the bulk superfluid density, is the coherence length, m 4 is the 4He atom mass, k B is Boltzmann's constant, and T is the absolute temperature. At each value of x the amplitudes C agree well with the corresponding amplitude for sb /, and g equals 1.17 ± 0.04 for all cases. Measurements of the velocity of second sound at x = 0.000, 0.190, 0.401, and 0.450 are also reported.Work supported by U.S. Department of Energy contract EY-76-S-02-1569.  相似文献   
24.
C-axis oriented ZnO thin films were grown on silicon (100) and (111) substrates by pulsed laser deposition. Low temperature photoluminescence spectra show besides the peaks of free excitons, of defect bound excitons, and of a donor-acceptor pair transition a new doublet at 3.328/3.332 eV. The doublet seems to originate from the columnar textured ZnO film structure. A corresponding structural dependence of the broadening parameter of the infrared dielectric functions was derived from spectroscopic ellipsometry in the spectral range from 380 to 1200 cm− 1. The wave numbers of the E1 transverse optical and A1 longitudinal optical phonon modes of the ZnO films on silicon are determined to be 406 and 573 cm− 1, respectively. These values are slightly smaller than those of single-crystalline ZnO thin films on sapphire.  相似文献   
25.
This study was initiated to examine the feasibility of providing multimedia mail, in particular video mail, on the existing World Wide Web platform. In this instance, the Web browser will act as the user agent of the mailing system. With this, users will be able to compose, send and read video mail directly on the Web. This paper examines a number of possible system architectures that can be employed for the development of video mail. Based on the following key issues: portability of system, flexibility of system, Internet standard support, security and authentication, and message compression and storage, a final architecture was selected to build video mail. The approach taken is that the system will be interfaced to the Web using a standard HyperText Transfer Protocol (HTTP) server and a standard Web browser. This is achieved through the use of Common Gateway Interface (CGI) programs and forms which reside in a standard HTTP server to provide the functionality of video mail, and a separate mail server for the storage and management of messages. This will cause the HTTP server to behave as if it is an electronic mail (E-mail) system. Video mail has been successfully implemented at the School of Applied Science, Nanyang Technological University, Singapore. The development work has been carried out on a Sun SPARC5 workstation and the Typhoon relational database system was used to construct the mail server. All software codes were written in C or C++. A video capturing application used in conjunction with a SunVideo card has been developed for video and audio recording. The paper also addresses implementation issues pertaining to the use of CGI programs, mail server development, and video and audio management.  相似文献   
26.
New inorganic–organic hybrid structures based on metal complexes have become of increasing interest over the last few decades in the search for new materials. Many different polypyridyl metal complexes have been investigated. Recently, a strong increase in interest regarding 2,2′:6′,2″‐terpyridine has been observed. In particular, octahedral bis‐2,2′:6′,2″‐terpyridine metal complexes offer the advantages of increased symmetry and, in the case of ruthenium(III )/ruthenium(II ) complexation, an entrance to a directed complexation technique. Apart from the combination with polymeric systems, ordered inorganic–organic structures on surfaces are becoming better understood concurrently with the development of sophisticated nanotechnology characterization techniques. There are many ongoing efforts that include terpyridine complex structures, especially concerning photophysical processes such as solar light to energy conversion. This review deals with the incorporation of terpyridine complexes into polymeric structures such as poly(ethylene glycol), poly(styrene), dendrimers, biomacromolecules, micelles, and resins, as well as the combination of terpyridine complexes with surfaces for electrocatalytic, photophysical, and self‐assembly purposes.  相似文献   
27.
Imaging of edges to nanometer resolution using a novel non-contact technique is presented. This technique relies on positioning an optical beam to the edge, and simultaneously scanning, and measuring differential changes in off-specular scatter. Data may be used to calculate the radius at the edge to high accuracy. The experimental apparatus is capable of producing diffraction images of features on surfaces arising from processes used in sample preparation. Images of the cleaved edge of an optical fiber, an Au pad on Si, and cleaved quartz measured on this apparatus are presented. This technique could also be utilized to analyze cleaved laser diodes, micro-optics, MEMS devices, and diamond cutting tools.  相似文献   
28.
Outlier detection research has been seeing many new algorithms every year that often appear to be only slightly different from existing methods along with some experiments that show them to “clearly outperform” the others. However, few approaches come along with a clear analysis of existing methods and a solid theoretical differentiation. Here, we provide a formalized method of analysis to allow for a theoretical comparison and generalization of many existing methods. Our unified view improves understanding of the shared properties and of the differences of outlier detection models. By abstracting the notion of locality from the classic distance-based notion, our framework facilitates the construction of abstract methods for many special data types that are usually handled with specialized algorithms. In particular, spatial neighborhood can be seen as a special case of locality. Here we therefore compare and generalize approaches to spatial outlier detection in a detailed manner. We also discuss temporal data like video streams, or graph data such as community networks. Since we reproduce results of specialized approaches with our general framework, and even improve upon them, our framework provides reasonable baselines to evaluate the true merits of specialized approaches. At the same time, seeing spatial outlier detection as a special case of local outlier detection, opens up new potentials for analysis and advancement of methods.  相似文献   
29.
This review summarizes the results obtained in a research programme sponsored by the Ministry of Interior of the FRG on fundamental principles of a structural design code for heat exchanging components in nuclear process heat plants. Materials selection and design data, methods for dimensioning and the limitation of stress, strain, creep fatigue and buckling as well as environmental effects are discussed.  相似文献   
30.
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