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71.
The purpose of this paper is to show that, within experimental uncertainty, the change in volume with stress obtained by quasi-static uniaxial-strain tests matches that obtained by hugoniot experiments over the same pressure range for quartz phenolic. The result of these tests shows that comparing the data by both techniques is meaningful. In addition, the use of the relatively simple and inexpensive quasi-static uniaxial-strain test (strain rates of 10?4/sec) may provide designers and materials engineers a method for rapid surveying of materials for their hugoniot properties. 相似文献
72.
73.
This paper presents the design of a unique materials-testing system capable of medium strain rates of from 10?4 to 102/s. The design incorporates both closed-loop hydraulic operation with that of open-loop pneumatic operation. A novel design permits accurate specimen alignment and a stiff frame which exceeds 17×106 lb/in. (11.7×104 MPa). The mechanine is able to perform conventional tension/compression tests, fatigue tests and, with slight modification, biaxial-stress-tube tests and triaxial-stress tests. The accurate alignment capability coupled with high frame stiffness and the pneumatic operation enables the testing of brittle materials with rigid grips. Titanium 6-6-2 was tested in both tension and compression at strain rates from 10?4 to about 10/s at four selected temperatures. The material showed a slight strain-rate sensitivity. Yield stress was shown to increase with strain rate while ductility decreased at each test temperature. 相似文献
74.
The rainbow schlieren deflectometry technique was used to measure oxygen concentrations in a laminar, isothermal helium jet
discharged vertically into ambient air. The concentration distributions were inferred from the color schlieren image by taking
into consideration the sampling interval and noise in measurements, especially near the jet center. Excellent quantitative
agreement was reached between measurements from schlieren and a continuous sampling probe. This work demonstrates the capability
of the schlieren technique for providing accurate, spatially-resolved, nonintrusive, full-field of view measurements of species
concentration in an isothermal binary system. Because the basic quantity measured is the refractive index, the present schlieren
technique can be extended for quantitative measurements of other scalar flow properties related to the refractive index.
Received: 21 April 1997 / Accepted: 14 November 1997 相似文献
75.
Anton-Culver H Ziogas A Bowen D Finkelstein D Griffin C Hanson J Isaacs C Kasten-Sportes C Mineau G Nadkarni P Rimer B Schildkraut J Strong L Weber B Winn D Hiatt R Nayfield S 《Community genetics》2003,6(3):171-177
OBJECTIVE: The National Cancer Institute established the Cancer Genetics Network (CGN) to support collaborative investigations into the genetic basis of cancer susceptibility, explore mechanisms to integrate this new knowledge into medical practice, and identify ways of addressing the associated psychosocial, ethical, legal, and public health issues. SUBJECTS AND METHODS: The CGN has developed the complex infrastructure required to support the projects, including the establishment of guidelines and policies, uniform methods, standard questionnaires to be used by all of the centers, and a standard format for submission of data to the Informatics Center. Cancer patients and their family members have been invited to enroll and be included in a pool of potential study participants. The Information Technology Group is responsible for support of the design, implementation, and maintenance of the multicenter Network-wide research protocols. RESULTS: As of January 2004, the CGN contained data on 23,995 probands (participants) and 425,798 family members. As a resource for cancer genetic studies, the CGN has a large number of probands and first-degree relatives with and without cancer and with multiple ethnicities. Different study designs can be used including case-control, case-case, and family studies. CONCLUSIONS: The unique resources of the CGN are available for studies on cancer genetic susceptibility, translational research, and behavioral research. The CGN is now at a point where approved collaborators may have access to enrolled patients and their families for special studies, as well as to the clinical, environmental and family cancer history data banked in the Informatics Center. 相似文献
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77.
W. Hempel C. Paal W. Hartmann G. A. Burrell G. G. Oberfell O. Brunck Mathers J. E. Lee J. W. Robertson F. M. Seibert P. Lebeau A. Damiens O. Brunck L. A. Levy F. St. Sinnatt B. J. Cramer E. H. Weiskopf J. I. Graham Th. F. Winmill F. Haber F. Löwe O. Mohr R. L. von Klemperer O. Wolft E. Müller E. Reinhardt J. N. Pring Juan Calafat y Leon M. Guichard R. Nowicki John J. Griffin A. Sons L. Hamburger H. Filippo Izn Ch. Moureau G. Lunge und A. Rittener 《Fresenius' Journal of Analytical Chemistry》1915,54(10):504-509
Ohne Zusammenfassung 相似文献
78.
The concentrations of D-glucose and D-galactose in plasma of galactosemic rats were quantitatively measured by a liquid chromatographic method, based on retention of the weakly ionized monosaccharides by an anion exchange column under alkaline conditions, elution with 9 mmol/L NaOH, and electrochemical detection. This method is both simple and sensitive, since very dilute plasma samples can be directly analysed. 相似文献
79.
Kent Griffin 《Linear algebra and its applications》2006,419(1):107-124
An order O(2n) algorithm for computing all the principal minors of an arbitrary n × n complex matrix is motivated and presented, offering an improvement by a factor of n3 over direct computation. The algorithm uses recursive Schur complementation and submatrix extraction, storing the answer in a binary order. An implementation of the algorithm in MATLAB® is also given and practical considerations are discussed and treated accordingly. 相似文献
80.