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81.
Let be the angle between a line and a random k-space in Euclidean n-space R
n. Then the random variable cos2 has the beta distribution. This result is applied to show (1) in R
nthere are exponentially many (in n) lines going through the origin so that any two of them are nearly perpendicular, (2) any N-point set of diameter d in R
nlies between two parallel hyperplanes distance 2d{(log N)/(n-1)}1/2 apart and (3) an improved version of a lemma of Johnson and Lindenstrauss (1984, Contemp. Math., 26, 189–206). A simple estimate of the area of a spherical cap, and an area-formula for a neighborhood of a great circle on a sphere are also given. 相似文献
82.
83.
84.
We present a simple proof for the generalizations of a result due to Wallace and a result due to Miquel to higher dimensions. 相似文献
85.
The palladium-catalyzed oxidative coupling of thiophenes and furans with alkenes proceeds in the presence of copper and lithium salts as oxidant and additive, respectively, under weakly basic or almost neutral conditions to afford the corresponding vinylated heteroarenes. Under such conditions, diphenyl(hydroxy)methyl and acetal functions on the heteroarene substrates are tolerable. The former function on a thiophene ring can be substituted by palladium-catalyzed arylation via C-C bond cleavage after the vinylation to produce 2-aryl-5-vinylthiophenes. 相似文献
86.
Y. Maehara 《Surface science》2006,600(18):3575-3580
Phase transitions of K on Mo(1 1 0) have been studied by RHEED technique. As Ba and Cs structures on the bcc(1 1 0) surface, surface structures of K were hexagonal from RT to 250 °C for θ > 0.9 ML. The hexagonal structure successively expanded from α to γ structure with Nishiyama-Wassermamm (N-W) orientation relationship. The nearest neighbor spacing in the α structure at RT was 4.50 Å, which is very closed to the atomic distance of K in metal, and stretched to 5.14 Å in the γ structure at T = 200 °C. At temperatures greater than T = 250 °C, the γ structure oriented in N-W and Kurdjumov-Sachs (K-S) relationships at the same time and stayed up to the temperature of 450 °C. These two orientations of γ structure also appeared in all temperature range for 0.4 < θ < 0.9 ML. 相似文献
87.
H. Maehara 《Annals of the Institute of Statistical Mathematics》2004,56(2):397-402
DropN random caps all of the same angular radius
on a unit sphere. LetU denote the part of the surface covered by these caps. We prove that if
, then the probability thatU is connected tends to 1 asN→∞, while ifc<1, then the probability thatU is connected tends to 0 asN→∞. 相似文献
88.
H. Maehara 《Discrete and Computational Geometry》1995,13(1):585-592
We present a special similarity ofR
4n
which maps lattice points into lattice points. Applying this similarity, we prove that if a (4n−1)-polytope is similar to a lattice polytope (a polytope whose vertices are all lattice points) inR
4n
, then it is similar to a lattice polytope inR
4n−1, generalizing a result of Schoenberg [4]. We also prove that ann-polytope is similar to a lattice polytope in someR
N
if and only if it is similar to a lattice polytope inR
2n+1, and if and only if sin2(<ABC) is rational for any three verticesA, B, C of the polytope. 相似文献
89.
Nakagishi Y Morimoto Y Fujita M Ozeki Y Maehara T Kikuchi M 《Photochemistry and photobiology》2007,83(5):1220-1225
Airway stenosis in childhood is resistant to conventional treatments. Endoscope-assisted photodynamic therapy (PDT) is a potent candidate for the therapeutic modality owing to the easy approach to the tracheal lesion and low degree of invasiveness. The aim of the present study was to examine whether a photosensitizer preferentially accumulates in the lesion of airway stenosis in order to explore the possible applicability of PDT. The tracheal mucosa of rabbits was scraped off, and the rabbits were intravenously administered with Photofrin. The tissue concentration of Photofrin was quantitatively measured by fluorometric analysis. Granulation formation was seen in the mucosa-deprived lesion, causing airway stenosis. Photofrin concentration in the granulation tissue was four-fold higher than that in the intact trachea and 10-fold higher than that in the liver, spleen, skin and muscle. Photofrin preferentially accumulated in the lesion of airway stenosis. A preliminary experiment on PDT using transtracheal illumination showed an amelioration of airway stenosis, resulting in reduction in respiratory stridor. 相似文献
90.
Minoru Maehara Koshi Ikeda Hiroaki Kurokawa Naoto Ohmura Shigeki Ikeda Yuzo Hirokawa Saori Maehara Keita Utsunomiya Noboru Tanigawa Satoshi Sawada 《Magnetic resonance imaging》2014