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排序方式: 共有1308条查询结果,搜索用时 15 毫秒
161.
M Motomura T Hoshino G Tomonaga S Morioka Y Shimono 《Canadian Metallurgical Quarterly》1977,41(9):983-989
Thirteen patients with aortic regurgitation (AR) and 13 with mitral regurgitation (MR) were compared quantitatively from the standpoint of their vector-cardiograms (VCG). Vectorcardiographic parameters were also compared with left ventricular angiographic parameters. The QR time interval was longer and the magnitude of the spatial maximum QRS vector was larger in the AR group, but these differences were thought to be attributed to the differences in length of the left ventricular long axis and the left ventricular end diastolic volume (LVEDV). In the AR group, the ratio of the width to the long axis of the QRS loop in the horizontal plane correlated well with the length of the left ventricular long axis and the angle made by the axis from the middle of the aortic valve to the left ventricular apex and the horizontal axis in the lateral view of the angiogram. In the MR group, these correlations were poor. 相似文献
162.
J Guzowski MM Paparella K Nageswara T Hoshino 《Canadian Metallurgical Quarterly》1976,86(8):1141-1146
Meningiomas should be considered in the differential diagnosis of otologic tumors arising from the middle ear and mastoid. It is generally recognized that meningiomas may invade the temporal bone via direct extension from the intracranial space (secondary). It is not generally recognized that meningiomas can develop initially in the middle ear cleft (primary). Representative cases of primary and secondary meningiomas of the temporal bone are described and clinical aspects of diagnosis surgical management are discussed. In order to assess the pathogenesis of meningiomas of the temporal bone, histological studies were done on 200 temporal bone specimens. In certain specimens, ectopic arachnoid granulations, from which primary meningiomas may originate, were identified and described, according to location. One specimen was most unusual in that it contained ectopic glial as well as arachnoidal tissue. 相似文献
163.
Kazutomo Hoshino Yoshiaki IIjima Ken-Ichi Hirano 《Metallurgical and Materials Transactions A》1982,13(7):1135-1139
Interdiffusion coefficients in copper-rich copper-zinc solid solutions containing up to 8 at. pct of Zn at 1168 K have been
determined by Matano's analysis using semi-infinite diffusion couples consisting of pure copper and Cu-Zn alloys with Kirkendall
markers. From the marker shift and Darken's relation, intrinsic diffusion coefficients, DZn and DCu, in the alloys containing 3.2 and 4.7 at. pct of Zn have been determined. Further, using thin plate couples, DZn and DCu in Cu alloys containing 0.9, 2.3, 3.5, and 4.6 at. pct of Zn at 1168 K have been determined by Heumann's method. The ratio
of the intrinsic diffusion coefficients, DZn/DCu, has been found to be about two for all the compositions examined. Using the values of the intrinsic diffusion coefficient
of copper at infinite dilution of zinc obtained by extrapolating the concentration dependence of DCu, and the self- and impurity diffusion coefficients in pure copper, the vacancy flow factor has been estimated to be - 0.22-0.15
+0.06 at 1168 K. By combining this value of the vacancy flow factor with the solute enhancement factor of solvent diffusion determined
by Peterson and Rothman, the correlation factor for impurity diffusion of Zn in Cu at 1168 K has been evaluated to be 0.5,
which is in good agreement with the value of 0.47 determined by Peterson and Rothman based on the isotope effect measurement.
KAZUTOMO HOSHINO, formerly Graduate Student, Tohoku University is now with Materials Science Division, Argonne National Laboratory,
Argonne, IL 60439. YOSHIAKI IIJIMA, Instructor, and KENICHI HIRANO, Professor, are both with the Department of Materials Science,
Faculty of Engineering, Tohoku University, Sendai 980, Japan. 相似文献
164.
Extraction of a plasma time-activity curve from dynamic brain PET images based on independent component analysis 总被引:1,自引:0,他引:1
Naganawa M Kimura Y Ishii K Oda K Ishiwata K Matani A 《IEEE transactions on bio-medical engineering》2005,52(2):201-210
A compartment model has been used for kinetic analysis of dynamic positron emission tomography (PET) data [e.g., 2-deoxy-2-18F-fluoro-D-glucose (FDG)]. The input function of the model [the plasma time-activity curve (pTAC)] was obtained by serial arterial blood sampling. It is of clinical interest to develop a method for PET studies that estimates the pTAC without needing serial arterial blood sampling. For this purpose, we propose a new method to extract the pTAC from the dynamic brain PET images using a modified independent component analysis [extraction of the pTAC using independent component analysis (EPICA). Source codes of EPICA are freely available at http://www5f.biglobe.ne.jp/?kimura/Software/top.html]. EPICA performs the appropriate preprocessing and independent component analysis (ICA) using an objective function that takes the various properties of the pTAC into account. After validation of EPICA by computer simulation, EPICA was applied to human brain FDG-PET studies. The results imply that the EPICA-estimated pTAC was similar to the actual measured pTAC, and that the estimated blood volume image was highly correlated with the blood volume image measured using 15O-CO inhalation. These results demonstrated that EPICA is useful for extracting the pTAC from dynamic PET images without the necessity of serial arterial blood sampling. 相似文献
165.
Microscopic observation of carbons obtained from pure aromatic hydrocarbons by the aid of carbonization catalysts was carried out to clarify the microstructure of these carbons of different features. Reflected polarized-light microscopy distinguished needle, mosaic and isotropic cokes, former two of which were produced with aluminum chloride and the last with potassium. High resolution microscopy revealed that these carbons calcined at 1250° had different degree of layered structure, corresponding to the crystallographic parameters of these samples graphitized at 2500°C. The reasons for the carbons produced with potassium to be non-graphitizable are discussed from the macro- and micro-features of the carbons. 相似文献
166.
167.
168.
The following well-known equation permits the ready determination of M n from a single osmotic pressure measurement at a known concentration, if the second virial coefficient is previously given: On this basis, the one-point method was investigated to determine the number-average molecular weight. It was found that this method was applicable to commercial polymers. However, in this application, the dependence of Γ2 on molecular weight distribution has to be kept in mind. 相似文献
169.
170.
An enzyme which participated in the oxidation of hydroxylamine to nitrite from was partially purified Alcaligenes faecalis, and some of its properties were studied. The enzyme oxidized aerobically pyruvic oxime to nitrite in the presence of hydroxylamine or ascorbate. As molecular oxygen equimolar to nitrite formed was consumed in the enzymatic oxidation of pyruvic oxime to nitrite, the enzyme was thought to be a dioxygenase. It was an iron protein, and a reducing reagent was required to keep the iron in the ferrous state for the action of the enzyme. 相似文献