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91.
A secure optical storage based on a configuration of a joint transform correlator by use of a photorefractive material is presented. A key code designed through the use of an optimized algorithm so that its Fourier transform has a uniform amplitude distribution and a uniformly random phase distribution is introduced. Original two-dimensional data and the key code are placed side-by-side at the input plane. Both of them are stored in a photorefractive material as a joint power spectrum. The retrieval of the original data can be achieved with the same key code. We can record multiple two-dimensional data in the same crystal by angular multiplexing and/or key code multiplexing.  相似文献   
92.
Compressive creep characteristics at 1773, 1873, and 1973 K, oxidation resistance over 1000 h at a temperature of 1973 K in ambient air, and the thermal stability characteristics at 1973 K in ambient air of a unidirectionally solidified Al2O3/YAG eutectic composite were evaluated. At a test temperature of 1873 K and a strain rate of 10–4/s, the compressive creep strength of a eutectic composite manufactured by the unidirectional solidification method is approximately 13 times higher than that of a sintered composite with the same chemical composition. The insite eutectic composite also showed greater thermal stability, with no change in mass after an exposure of 1000 hours at 1973 K in ambient air. The superior high-temperature characteristics are closely related to such factors as (1) the in-situ eutectic composite having a microstructure, in which single crystal Al2O3 and single crystal YAG are three-dimensionally and continuously connected and finely entangled without grain boundaries and (2) no amorphous phase is formed at the interface between the Al2O3 and the YAG phases.  相似文献   
93.
To assess the frictional properties at the wedge of a toroidal field coil of a tokamak fusion reactor, friction tests were conducted using structural steel, JN2, against various materials in a vacuum at low temperatures under a normal load of 10 N and a peak-to-peak sliding amplitude of 100 μm. The temperature was mainly ≈ 5 K and the ambient pressure ≈ 10−3 Pa. The relationship between the frictional characteristics and the number of cycles depends on both the material combination and temperature. Two typical patterns of behaviour were observed at 5 K depending on the combination; fairly constant friction and very high and fluctuating friction. The high friction was caused by severe adhesion between surfaces. Temperature dependence of friction was also observed for JN2-copper.  相似文献   
94.
Metallurgical and Materials Transactions A - This study examines strain distribution occurring in the high-pressure sliding (HPS) processing for rods of pure Al and an AZ61 alloy. The strain...  相似文献   
95.
2-Carboxybenzaldehyde dehydrogenase from the phenanthrene-degrading bacterium Nocardioides sp. strain KP7 was purified and characterized. The purified enzyme had a molecular mass of 53 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and 205 kDa by gel filtration chromatography. Thus, the homotetramer of the 53-kDa subunit constituted an active enzyme. The apparent Km and kcat values of this enzyme for 2-carboxybenzaldehyde were 100 microM and 39 s(-1), respectively, and those for NAD+ were 83 microM and 32 s(-1), respectively. The structural gene for this enzyme was cloned and sequenced. The length of the gene was 1,455 bp. The nucleotide sequence of the 10,279 bp of DNA around the gene for 2-carboxybenzaldehyde dehydrogenase was also determined, and seven open reading frames were found in this DNA region. These were the genes for 1-hydroxy-2-naphthoate dioxygenase (phdI) and trans-2'-carboxybenzalpyruvate aldolase (phdJ), orf1, the gene for 2-carboxybenzaldehyde dehydrogenase (phdK), orf2/orf3, and orf4. The amino acid sequence of the orf1 product was similar to that of the aromatic hydrocarbon transporter gene (pcaK) in Pseudomonas putida PRS2000. The amino acid sequence of the orf4 product revealed a similarity to cytochrome P-450 proteins. The region between phdK and orf4 encoded orf2 and orf3 on different strands. The amino acid sequences of the orf2 and orf3 products exhibited no significant similarity to the reported sequences in protein databases.  相似文献   
96.
OBJECTIVES: This study sought to evaluate the intravascular structure as depicted by intravascular ultrasound after successful primary angioplasty (i.e., without thrombolytic therapy) for acute myocardial infarction and to investigate the related predictors of acute coronary occlusion. BACKGROUND: The usefulness of primary angioplasty for acute myocardial infarction is still limited by early reocclusion. There are few data regarding the intravascular ultrasound findings after primary angioplasty. METHODS: Intravascular ultrasound was performed in 27 patients after successful primary angioplasty. Repeat coronary angiography was performed 15 min later, on the following day and 1 month after angioplasty. RESULTS: Abrupt occlusion occurred in 8 of 27 patients. Angiographic variables in patients with versus those without abrupt occlusion were not significantly different. Intravascular ultrasound disclosed a significantly smaller lumen area ([mean +/- SD] 2.49 +/- 0.72 vs. 5.06 +/- 1.52 mm2, p < 0.001) and a significantly greater percent plaque area (80.5 +/- 9.1% vs. 63.7 +/- 7.8%, p < 0.001) in patients with abrupt occlusion. There was no significant difference in external elastic membrane cross-sectional area. We classified the ultrasound appearance of the intravascular structure as smooth, irregular or filled. Abrupt occlusion occurred in none of 6 patients with a smooth intravascular structure, 24% of 17 patients with an irregular structure and in all 4 with a filled structure (p < 0.05). In the latter group, the lumen was filled with bright speckled or low echogenic material, although angiography revealed excellent coronary dilation in all these arteries. CONCLUSIONS: Intravascular ultrasound revealed a narrow lumen in coronary arteries showing abrupt occlusion after successful primary angioplasty, even though angiography disclosed successful dilation. Arteries with a lumen filled with bright speckled or low echogenic material frequently develop abrupt occlusion.  相似文献   
97.
We describe cystic lymphangiomatosis with intestinal bleeding developing multiple lymphangiomas in the small intestine, mesentery, mesocolon, omentum, retroperitoneum, and spleen. Small intestinal fluorography showed multiple polypoid lesions, mainly in the jejunum. Ultrasonography, computed tomography, and magnetic resonance imaging showed diffuse cystic tumors in the mesentery and spleen. Cystic lymphangiomatosis was proved by histologic findings of the biopsied specimen at laparotomy.  相似文献   
98.
Kiritani et al. encountered a large number of vacancy clusters in heavily deformed thin metal films at room temperature. In the present work, thin films of aluminum and copper were loaded to fracture in liquid nitrogen and transferred directly to the TEM without warming up (Cryo-transfer TEM). In thin films of Al and Cu deformed at 78 K, many defect clusters were observed at 120 K. In thin Al films, small defect clusters disappeared by the 120 keV electron irradiation. Upon isochronal annealing, some of the dislocation loops grew in their size, which is much larger than those observed at 120 K. However, in regions that were not exposed to electron irradiation at 120 K, only a large number of stacking fault tetrahedra were observed after room temperature annealing. In copper, the 200 keV electron beam did not significantly change the defect clusters observed at 120 K.  相似文献   
99.
ABSTRACT

The high-pressure sliding (HPS) process was applied for grain refinement of a pipe form of an Al-3wt%Mg-0.2wt%Sc alloy by developing two types of straining techniques (called in this study anvil sliding and mandrel sliding). To achieve a homogeneous microstructure throughout the cross-section of the pipe, the sample is rotated around the longitudinal axis every after sliding operation by introducing multi-pass technique, named multi-pass HPS (MP-HPS) as developed earlier for rods. The MP-HPS-processed sample shows ultrafine-grained structures with an average grain size of ~260 and ~300?nm after the HPS processing using anvil sliding and mandrel sliding. The samples also exhibit superplasticity with total elongations well more than 400%, respectively. A finite-element method is used to simulate the evolution of strain in the HPS processing and demonstrates that the simulation well represents the experimental results.  相似文献   
100.
Although the majority of patients with pituitary tumor, undergoing transsphenoidal microsurgery, have a low incidence of hormonal deficiency after surgery, the endocrinological evaluations should be carefully done before and after surgery. Glucocorticoid replacement is necessary in patients with Cushing's disease during and after surgery as well as those with adrenal insufficiency. Repeated CRF test is useful to assess the secondary adrenal insufficiency of Cushing's disease after surgery. Patients with impaired secretion of both ACTH and TSH should receive glucocorticoid replacement before thyroid hormone replacement in order to avoid adrenal crisis. A combination of CRF, GRF, TRH and GnRH is a safer and more reliable test to evaluate pituitary function than the conventional triple test consisting of insulin, TRH and GnRH, especially in patients predicted to have pituitary-adrenal insufficiency. Diabetes insipidus(DI), immediately after pituitary surgery, should be treated with subcutaneous injection of Pitressin. Even if patients seem to have recovered from DI several days after surgery, they must be monitored closely because of the incidence of triphasic DI. Less attention has been given to replacement for GH deficiency in adults. Recent reports revealed that GH replacement in adults with GH deficiency decreases visceral fat tissue and increases plasma calcium, phosphorus, osteocalcin and procollagen III levels. GH replacement will become more popular even in adults. Many options and technological advantages in the diagnosis and treatment of pituitary tumors have developed in a decade. In the near future, post-operative patients with pituitary tumors must be cared for in view of the "quality of life".  相似文献   
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