A physical simulation was carried out to investigate the realistic experiment of bulk solidifying the Zn-Bi hyper-monotectic alloy under various compound electric-magnetic fields(CEMF).For this experiment,two crucial parameters determinate the cast microstructure,the one is electric-magnetic force(EMF)and the other is the frequency of AC current.Results show that the minor phase could be mixed in the other phase from the initial layered structure when the EMF above a specific value under fixed frequency,and the average diameter of minor phase droplet decreases with increasing EMF.The evolution of the liquid phases structure is reasonable agree with the realistic experiment of Zn-Bi hyper-monotectic alloy,which suggests that the mechanism revealed by the physical simulation could represent the one in the realistic experiment. 相似文献
Sarcomatoid carcinoma of head and neck mucosal sites is a rare high-grade malignancy that may cause diagnostic and therapeutic controversies. A characteristic of this entity consistently reported but not entirely validated is its relative radioresistance and the general belief is that surgery is the treatment of choice. The objective of this retrospective study was to determine if patients treated with radiation for early glottic sarcomatoid carcinoma had worse outcomes than those achieved with irradiation for the more typical squamous cell carcinoma. Twenty-eight cases of early stage (T1-T2) sarcomatoid carcinoma of the larynx treated with definitive doses of megavoltage irradiation between 1969 and 1995 at The University of Texas M. D. Anderson Cancer Center form the cohort for this analysis. All pathologic material was reviewed to confirm the diagnosis. All tumors manifested spindle cell features with marked cytomorphologic abnormalities characteristic of this entity. Sixteen tumors (57%) had the more typical polypoid gross morphology of sarcomatoid carcinoma. Twenty-one patients (75%) were staged T1 and seven patients (25%) had stage T2 disease. All patients were treated with small laryngeal fields, median size 20 cm2, and to a median dose of 65 Gy. Follow-up ranged from 1.5 to 24 years (median, 10 years). Four patients (14%) had local disease recurrence, and all had salvage total laryngectomies and remained free of local disease. The 5-year actuarial local control rates for patients with T1 and T2 lesions were 94% and 54%, respectively. Only one patient developed regional and distant disease. The 10-year actuarial disease-specific and overall survival rates were 92% and 63%, respectively. Patients with early stage sarcomatoid carcinoma of the glottis treated with radiation had similar control rates to irradiated patients with similar volume disease with the more typical squamous cell carcinoma. The authors contend that the histologic diagnosis of sarcomatoid carcinoma by itself should not influence the decision to treat a patient with early stage glottic disease with irradiation. 相似文献
We show that in a free F-algebra endowed with a strict order we can associate with a complete rewriting system in the sense of Knuth-Bendix an equivalent proper (minimal) complete system. Furthermore, if the complete system is compatible with a strict order, then the equivalent proper complete system is unique. 相似文献
In this paper, we derive time-minimal systolic arrays for Gaussian elimination and the Algebraic Path Problem (APP) that use a minimal number of processors. For a problem of size n, we obtain an execution time T(n) = 3n −1 using A(n) = n2/4+O(n) processors for Gaussian elimination, and T(n) = 5n −2 and A(n) = n3/+O(n) for the APP. 相似文献
In this paper, we define the notion of biRFSA which is a residual finate stateautomaton (RFSA) whose the reverse is also an RFSA. The languages recognized bysuch automata are called biRFSA languages. We prove that the canonical RFSA of abiRFSA language is a minimal NFA for this language and that each minimalNFA for this language is a sub-automaton of the canonical RFSA. This leadsto a characterization of the family of biRFSA languages.In the second part of this paper, we define the family of biseparable automata. We prove that every biseparable NFA is uniquely minimal among all NFAs recognizinga same language, improving the result of H. Tamm and E.Ukkonen for bideterministic automata. https://doi.org/10.1051/ita:2008022 相似文献
Previous functional MRI findings have indicated that a premotor-parietal network is involved in the perceptual processing of sequential information. Given that premotor functions have traditionally been restricted to behaviors requiring motor or sensorimotor computations, the goal of the present patient study was to further investigate whether the lateral premotor cortex is critical in purely perceptual sequencing. Patients with either ventral premotor or inferior parietal lesions, in addition to patients with prefrontal lesions and age- and gender-matched healthy controls, were tested during the processing of temporal, object-specific, and spatial sequences. Results revealed that premotor patients as well as parietal patients showed significantly higher error rates than did healthy controls on all sequence tasks. In contrast, prefrontal patients showed no behavioral deficits. These findings support the significance of the ventrolateral premotor cortex, in addition to parietal areas, in nonmotor (attentional) functions. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
A two-dimensional mathematical model developed for vacuum-contact drying of wood was adapted to simulate superheated steam vacuum drying. The moisture and heat equations are based on the water potential concept whereas the pressure equation is formulated considering unsteady-state mass conservation of dry air. A drying test conducted on sugar maple sapwood in a laboratory vacuum kiln was used to infer the convective mass and heat transfer coefficients through a curve fitting technique. The average air velocity was 2.5 m s-1 and the dry-bulb temperature varied between 60 and 66°C. The ambient pressure varied from 15 to 11 kPa. Simulation results indicate that heat and mass transfer coefficients are moisture content dependent. The simulated drying curve based on transfer coefficients calculated from boundary layer theory poorly fits experimental results. The functional relation for the relative permeability of wood to air is a key parameter in predicting the pressure evolution in wood in the course of drying. In the case of small vacuum kilns, radiant heat can contribute substantially to the total heat transfer to the evaporative surface at the early stages of drying. As for conventional drying, the air velocity could be reduced at the latter stage of drying with little or no change to the drying rate. 相似文献
The main objective of this study is to investigate cutting parameter effects of surface roughness in a lathe dry boring operation. A full factorial design was used to evaluate the effect of six (6) independent variables (cutting speed, feed rate, depth of cut, tool nose radius, tool length and type of boring bar) and their corresponding two-level interactions. In this experiment, the dependant variable was the resulting fast cut surface roughness (R,). In order to perform all possible variable combinations, a total of 216 cuts were.
The results revealed that using short tool length always provide good surface roughness and that only slight improvement on surface roughness can be achieved by properly controlling the cutting parameters and/or the type of boring bar used. The results also revealed that using a long tool length may results in vibration that could be efficiently controlled by the use of a damped boring bar. With such a long tool length, the cutting variables become important factors to control in order to significantly improve surface roughness results with both types of boring bars. A prediction model is proposed for each types of boring bar. Both models are highly significant, p<0.00001, with coefficients of determination of 0.56 and 0.57 for a standard boring bar and a damped boring bar, respectively. 相似文献
The chemical oxidation of sucrose, isomaltulose and methyl isomaltuloside is described, with special focus on the use of the NaOCl–TEMPO oxidizing system. 相似文献