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61.
The flexure and compressive strengths of sapphire are dependent on crystal orientation and temperature. Most notably, the c -axis compressive strength decreases below the tensile strength at temperatures >400°C and falls to 2% of the room-temperature compressive strength at 800°C. Loss of compressive strength complicates the interpretation of flexure tests. Four-point flexure specimens with no component of c -axis compression increase in strength at temperatures >500°C; however, specimens that have c -axis compression decrease in strength. It has been observed that c -axis compression causes twinning on rhombohedral crystal planes. Intersection of twins on different rhombohedral planes causes fracture that leads to mechanical failure. 相似文献
62.
李效良 《石油石化物资采购》2010,(8):15-15
据工信部日前最新消息:今年上半年,我国西部地区水泥产量为2.3亿吨,同比增长25.9%,增速远高于东部和中部地区。但西部地区水泥出厂价格则呈持续下降态势。 相似文献
63.
Prof. Dr.-Ing. H. Weh Dipl.-Ing. H. May Dipl.-Math. W. Schmid 《Electrical Engineering (Archiv fur Elektrotechnik)》1986,69(5):307-320
Übersicht Zur Berechnung von Magnetfeldern mit beliebigen Materialverteilungen und beliebigen Anregungen wird die Differentialgleichung für das Vektorpotential angegeben und mit Hilfe der finiten Elemente Methode in ein algebraisches Gleichungssystem umgewandelt. Die Anwendung des Durchflutungsgesetzes führt wesentlich einfacher zu identischen Bestimmungsgleichungen. Eine Berücksichtigung der Nichtlinearitäten geschieht mit dem Newton Raphson Verfahren. Für den Sonderfall von anisotropen Stoffeigenschaften werden die Transformationsmatrizen angegeben. Zum Schluß wird ein Lösungsverfahren für schwach besetzte Gleichungssysteme beschrieben.
Verzeichnis der verwendeten Symbole A,A Vektorpotential - a, b, c Koeffizienten - B,B magnetische Induktion - b Anregungsvektor - f Formfunktion - G, F Gebiet - H,H magnetische Feldstärke - J Dreiecksfläche - K Integrationsweg - K Koeffizientenmatrix - L Dreieckskoordinaten - M,M Magnetische Polarisation - S Stromdichte - t Zeitkoordinate - v,v Geschwindigkeit - x, y, z Ortskoordinaten - elektrische Leitfähigkeit - =1/ Permeabilität - Reluktivität 相似文献
Numerical magnetic field calculations using discretization methods
Contents To calculate magnetic fields with arbitrary material distributions and excitations the given vector potential differential equation is transformed into an algebraic system of equations (Finite Element Method). The application of the ampere turns rule leads (considerably more simply) to identical equations. Allowance for non-linearities is provided by the Newton-Raphson method. The transformation matrices are given for anisotropic material properties. Finally, a solver for sparsely populated matrices is deseribed.
Verzeichnis der verwendeten Symbole A,A Vektorpotential - a, b, c Koeffizienten - B,B magnetische Induktion - b Anregungsvektor - f Formfunktion - G, F Gebiet - H,H magnetische Feldstärke - J Dreiecksfläche - K Integrationsweg - K Koeffizientenmatrix - L Dreieckskoordinaten - M,M Magnetische Polarisation - S Stromdichte - t Zeitkoordinate - v,v Geschwindigkeit - x, y, z Ortskoordinaten - elektrische Leitfähigkeit - =1/ Permeabilität - Reluktivität 相似文献
64.
Immunohistochemistry is used to demonstrate histamine-immunoreactivity in the CNS of spiders. We found histamine-immunoreactivity in the photoreceptors of different spiders. Therefore, we suggest that histamine is a neurotransmitter of photoreceptors in all arthropods, since it is also known to occur in the photoreceptors of the other main arthropod taxa (Merostomata, Crustacea, and Insecta). We also describe a system of only six omnisegmental histamine-immunoreactive neurons within the central nervous system. These histamine-immunoreactive neurons can be divided into two subgroups: a dorsal system with two cells per hemisphere and a ventral system with only one cell per hemisphere. All six cells have extended arborizations in both the motor and the sensory areas of all neuromeres in the suboesophageal ganglionic mass. In contrast to araneomorph spiders, two additional sets of histamine-immunoreactive neurons were detected in mygalomorph spiders. The first set consists of seventeen cells with their cell bodies located in the cheliceral ganglion and projecting to central areas of the protocerebrum. The second set contains many if not all sensory projections from the tarsal organs on all eight legs and the pedipalps to the Blumenthal neuropil. 相似文献
65.
Schmid P 《IEEE transactions on medical imaging》1999,18(2):164-171
In this paper a color-based segmentation scheme applied to dermatoscopic images is proposed. The RGB image is processed in the L* u* v* color space. A two-dimensional (2-D) histogram is computed with the two principal components and then smoothed with a Gaussian low-pass filter. The maxima location and a set of features are computed from the histogram contour lines. These features are the number of enclosed pixels, the surface of the base, and the height of the maximum. They allow for the selection of valid clusters which determine the number of classes. The image is then segmented using a modified version of the fuzzy c-means (FCM) clustering technique that takes into account the cluster orientation. Finally, the segmented image is cleaned using mathematical morphology, the region borders are smoothed, and small components are removed. 相似文献
66.
W Weder RA Schmid H Bruchhaus S Hillinger GK von Schulthess HC Steinert 《Canadian Metallurgical Quarterly》1998,66(3):886-92; discussion 892-3
BACKGROUND: Accurate staging of non-small cell lung cancer is essential for treatment planning. We evaluated in a prospective study the role of whole-body 2-[18F]fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) in mediastinal nodal staging with a positive predictive value of 96%. The study was continued to further evaluate the value of whole-body FDG PET in detecting unexpected extrathoracic metastases (ETMs) in patients qualifying for surgical treatment by conventional staging. METHODS: One hundred patients underwent clinical evaluation, chest and upper abdominal computed tomography scan, mediastinoscopy (lymph nodes greater than 1 cm on computed tomography), and routine laboratory tests. In 94 patients with stage IIIa or less and 6 with suspected N3 a whole-body FDG PET was performed. If clinical signs of ETMs were present additional diagnostic methods were applied. All findings in the FDG PET were confirmed histologically or radiologically. RESULTS: Unexpected ETMs were detected in 13 (14%) of 94 patients (stage IIIa or less) at 14 sites. In addition 6 of 94 patients were restaged up to N3 after PET. The suspected N3 disease (stage IIIb) on computed tomography was confirmed by PET in all 6 patients. There was no false positive finding of ETM. Weight loss was correlated with the occurrence of ETM: more than 5 kg, 5 of 13 patients (38%); more than 10 kg, 4 of 6 patients (67%). Pathologic laboratory findings were not predictive for ETM. CONCLUSIONS: Whole-body FDG PET improves detection of ETMs in patients with non-small cell lung cancer otherwise elegible for operation. In 14% of patients (stage IIIa or less), ETMs were detected, and in total, 20% of the patients were understaged. 相似文献
67.
M Schmid 《Canadian Metallurgical Quarterly》1998,87(42):1397-1401
The importance of a liver biopsy is summarized as follows: 1. A diagnostic liver biopsy may be helpful in otherwise unexplained liver disease, especially in cases with controversial or unexplicable patterns of laboratory findings or in chronic hepatitis without positive serological markers. 2. Liver histology is necessary for the assessment of the necroinflammatory activity of chronic hepatitis in order to decide on an eventual therapy. Liver biopsy is an important tool as well for the evaluation of liver transplantation in the end stage of several liver diseases as for the diagnosis of transplant-complications. 3. Follow-up biopsies are necessary for supervision of therapy of chronic hepatitis. Histology is the only reliable method for assessment of necroinflammatory activity. 相似文献
68.
Ludwig von Bernus Werner Rathgeb Rudi Schmid Friedrich Mohr Michael Krning 《Nuclear Engineering and Design》1994,151(2-3)
A tendency towards growing requirements for the inspection of austenitic piping can be observed in several countries. In Germany the revised KTA rule demands the UT inspection of austenitic and dissimilar metal welds in piping with diameters of 200 mm or more.On the basis of experience gained from austenitic piping with integranular stress corrosion cracking (IGSCC), longitudinal waves and mode conversion techniques are used. Depending on the geometry, material and grain orientation, spurious signals can be observed which require additional evaluation or analysis measurements.A promising new technique is based on horizontally polarized shear (SH) waves generated by electromagnetic acoustic transducers (EMATs). Investigations in the laboratory and field inspections showed that SH waves are well suited for the detection of longitudinal flaws, especially where the weld can be examined from one side only.For the complete solution of a given inspection problem SH waves can be combined with well-known standard techniques in order to provide redundant information for the characterization and sizing of indications.The investigation of possibilities of SH waves showed that the problem of cast austenitic steel inspection might not be solved using this technique. However, measurements using low frequency UT transducers showed promising results. 相似文献
69.
The conjugative plasmid pRSD2 carries a raf operon that encodes a peripheral raffinose metabolic pathway in enterobacteria. In addition to the previously known raf genes, we identified another gene, rafY, which in Escherichia coli codes for an outer membrane protein (molecular mass, 53 kDa) similar in function to the known glycoporins LamB (maltoporin) and ScrY (sucrose porin). Sequence comparisons with LamB and ScrY revealed no significant similarities; however, both lamB and scrY mutants are functionally complemented by RafY. Expressed from the tac promoter, RafY significantly increases the uptake rates for maltose, sucrose, and raffinose at low substrate concentrations; in particular it shifts the apparent K(m) for raffinose transport from 2 mM to 130 microM. Moreover, RafY permits diffusion of the tetrasaccharide stachyose and of maltodextrins up to maltoheptaose through the outer membrane of E. coli. A comparison of all three glycoporins in regard to their substrate selectivity revealed that both ScrY and RafY have a broad substrate range which includes alpha-galactosides while LamB seems to be restricted to malto-oligosaccharides. It supports growth only on maltodextrins but not, like the others, on raffinose and stachyose. 相似文献
70.
JL Harousseau JY Cahn B Pignon F Witz N Milpied M Delain B Lioure T Lamy B Desablens F Guilhot D Caillot JF Abgrall S Francois J Briere D Guyotat P Casassus B Audhuy Z Tellier P Hurteloup P Herve 《Canadian Metallurgical Quarterly》1997,90(8):2978-2986
Three intensive consolidation strategies are currently proposed to younger adults with acute myeloid leukemia (AML) in first complete remission (CR): allogeneic or autologous bone marrow transplantation (BMT) and intensive consolidation chemotherapy (ICC). Patients aged 15 to 50 years with de novo AML received an induction treatment with 7 days of cytarabine and either idarubicin or rubidazone. After achievement of a CR, patients up to the age of 40 and having an HLA-identical sibling were assigned to undergo an allogeneic BMT. All the other patients received a first course of ICC with high-dose cytarabine and the same anthracycline as for induction. They were then randomly assigned to either receive a second course of ICC with amsacrine and etoposide or a combination of busulfan and cyclosphosphamide followed by an unpurged autologous BMT. Of 517 eligible patients, 367 had a CR, but only 219 (59.5%) actually received the planned intensive postremission treatment (73 allogeneic BMT, 75 autologous BMT, and 71 ICC). With a median follow-up of 62 months, the 4-year disease-free survival (DFS) of the 367 patients in CR was 39.5%. The 4-year overall survival (OS) of the 517 eligible patients was 40.5%. In multivariate analysis, DFS and OS were influenced only by the initial white blood cell count and by the French-American-British classification. The type of postremission therapy had no significant impact on the outcome. There was no difference in the 4-year DFS and OS between 88 patients for whom an allogeneic BMT was scheduled (respectively, 44% and 53%) and 134 patients of the same age category and without an HLA-identical sibling (respectively, 38% and 53%). Similarly, there was no difference in the outcome between autologous BMT and ICC. The 4-year DFS was 44% for the 86 patients randomly assigned to autologous BMT and 40% for the 78 patients assigned to ICC (P = .41). The 4-year OS was similar in the two groups (50% v 54.5%, P = .72). The median duration of hospitalization and thrombocytopenia were longer after autologous BMT (39 v 32 days, P = .006, and 109.5 v 18.5 days, P = .0001, respectively). After a first course of ICC, a second course of chemotherapy is less myelotoxic than an unpurged autologous BMT but yields comparable DFS and OS rates. 相似文献