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991.
马银华  党平  崔晓波 《鞍钢技术》2021,(1):33-35,39
介绍了鞍钢股份有限公司鲅鱼圈钢铁分公司炼焦部7m焦炉烟气排放现状,阐述了焦炉烟气脱硫脱硝技术的工艺选择、工艺原理和技术特点.通过应用SDS干法脱硫+布袋除尘+中低温SCR脱硝技术,焦炉烟气SO2和NOX排放浓度分别达到了8~10 mg/m3和100~120 mg/m3,颗粒物排放浓度<10 mg/m3,均符合国家超低排放标准要求,具有推广和借鉴意义.  相似文献   
992.
The microscopic fracture behaviors of a C-Mn steel plate and of two types of weld metal in Charpy V, crack tip opening displacement (COD), and precracked impact specimens have been studied by observations of the size distribution of the cleavage-initiating particles, the morphology of the fibrous crack zones, the microstructure in the region initiating the cleavage crack, and the size distribution of microcracks remaining in the specimens. It has been found that the different values of the microscopic cleavage fracture stress, σf, measured in notched and precracked specimens of the same metal result from the change in the critical event (critical length) in the fracture processes. The critical event in the Charpy V-notched specimens at —45 °C to —65 °C is the propagation of a ferrite grain-sized microcrack into the ferrite matrix; however, in the precracked COD specimens at —110 °C, it is the propagation of a second-phase particle-sized microcrack into the neighboring ferrite grain. The change of the critical event is considered to be related to the difference of effective shear stress ahead of a notch root or a crack tip. The different sensitivities to the notch acuity of the base and weld metal result from their micro-structures. Finally, the prerequisite for establishing a correlation between Charpy V and COD tests is analyzed.  相似文献   
993.
The increasingly widespread use of mammographic screening for breast cancer has induced a considerable increase in the number of surgical biopsies. Fine-needle aspiration and microbiopsies can allow to reduce this number. 1) In patients with nodular densities of benign or indeterminate appearance, a negative fine-needle aspiration indicates that no further investigations are needed. In contrast, complete surgical excision is indicated in cases of stellate images. 2) In patients with potentially malignant microcalcifications, fine-needle aspiration is to little value, and microbiopsies should be performed. Indeterminate (type II or III) calcifications are the best indication, since negative microbiopsies may obviate the need for lumpectomy, if the negative predictive value of microbiopsies is sufficiently high in this indication. Focal suspicious microcalcifications (type IV or V) should be removed surgically for both diagnostic and therapeutic purposes. Type IV or V microcalcifications involving a large area of the breast can be investigated by initial microbiopsy; a positive result allows to recommend immediate mastectomy without prior lumpectomy. Fine-needle aspiration and microbiopsies should be performed as part of a multidisciplinary diagnostic strategy involving radiologists, surgeons, cytopathologists, and pathologists. This approach is the only means of improving the management of non palpable mammographic lesions and of reducing the number of unnecessary operation.  相似文献   
994.
Eight adolescents (ages 13-18 years) who sustained traumatic brain injury (TBI) and eight gender- and age-matched typically developing (TD) adolescents underwent event-related functional MRI (fMRI) while performing a Sternberg letter recognition task. Encoding, maintenance, and retrieval were examined with memory loads of one or four items during imaging. Both groups performed above a 70% accuracy criterion and did not differ in performance. TD adolescents showed greater increase in frontal and parietal activation during high-load relative to low-load maintenance than the TBI group. The TBI patients showed greater increase in activation during high-load relative to low-load encoding and retrieval than the TD group. Results from this preliminary study suggest that the capability to differentially allocate neural resources according to memory load is disrupted by TBI for the maintenance subcomponent of working memory. The overrecruitment of frontal and extrafrontal regions during encoding and retrieval following TBI may represent a compensatory process. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
995.
996.
In laboratory experiments, infants are sensitive to patterns of visual features that co-occur (e.g., Fiser & Aslin, 2002). Once infants learn the statistical regularities, however, what do they do with that knowledge? Moreover, which patterns do infants learn in the cluttered world outside of the laboratory? Across 4 experiments, we show that 9-month-olds use this sensitivity to make inferences about object properties. In Experiment 1, 9-month-old infants expected co-occurring visual features to remain fused (i.e., infants looked longer when co-occurring features split apart than when they stayed together). Forming such expectations can help identify integral object parts for object individuation, recognition, and categorization. In Experiment 2, we increased the task difficulty by presenting the test stimuli simultaneously with a different spatial layout from the familiarization trials to provide a more ecologically valid condition. Infants did not make similar inferences in this more distracting test condition. However, Experiment 3 showed that a social cue did allow inferences in this more difficult test condition, and Experiment 4 showed that social cues helped infants choose patterns among distractor patterns during learning as well as during test. These findings suggest that infants can use feature co-occurrence to learn about objects and that social cues shape such foundational learning in distraction-filled environments. (PsycINFO Database Record (c) 2011 APA, all rights reserved)  相似文献   
997.
A new approach to secure economic power dispatch   总被引:2,自引:0,他引:2  
This article presents a new nonlinear convex network flow programming model and algorithm for solving the on-line economic power dispatch with N and N−1 security. Based on the load flow equations, a new nonlinear convex network flow model for secure economic power dispatch is set up and then transformed into a quadratic programming model, in which the search direction in the space of the flow variables is to be solved. The concept of maximum basis in a network flow graph was introduced so that the constrained quadratic programming model was changed into an unconstrained quadratic programming model which was then solved by the reduced gradient method. The proposed model and its algorithm were examined numerically with an IEEE 30-bus test system on an ALPHA 400 Model 610 machine. Satisfactory results were obtained.  相似文献   
998.
For high-speed machines, in particular, it is very important to accurately predict natural frequencies of the rotor at the design stage so as to minimize the likelihood of failure. Finite-element analysis and experimental measurements are used to establish the natural frequencies and modes of the rotor of a high-speed permanent-magnet brushless motor, and to assess the influence of leading design parameters, such as the active length, the shaft diameter and extension, the bearings, and the material properties.  相似文献   
999.
Williams syndrome (WS) is a contiguous gene deletion disorder caused by haploinsufficiency of genes at 7q11.23. We have shown that hemizygosity of elastin is responsible for one feature of WS, supravalvular aortic stenosis (SVAS). We have also implicated LIM-kinase 1 hemizygosity as a contributing factor to impaired visual-spatial constructive cognition in WS. However, the common WS deletion region has not been completely characterized, and genes for additional features of WS, including mental retardation, infantile hypercalcemia, and unique personality profile, are yet to be discovered. Here, we present a physical map encompassing 1.5 Mb DNA that is commonly deleted in individuals with WS. Fluorescence in situ hybridization analysis of 200 WS individuals shows that WS individuals have the consistent deletion interval. In addition, we identify three novel genes from the common deletion region: WS-betaTRP, WS-bHLH, and BCL7B. WS-betaTRP has four putative beta-transducin (WD40) repeats, and WS-bHLH is a novel basic helix-loop-helix leucine zipper (bHLHZip) gene. BCL7B belongs to a novel family of highly conserved genes. We describe the expression profile and genomic structure for each of these genes. Hemizygous deletion of one or more of these genes may contribute to developmental defects in WS.  相似文献   
1000.
The five articles that make up the bulk of this special issue collectively illustrate new methods for examining the utility of sub-test and scale-level profile analysis. By necessity they are preliminary, but they illustrate methods that may indeed prove useful and may help resolve this divide between research and practice. This special issue grew out of a symposium conceived and organized by Cecil Reynolds at the American Psychological Association in 1998. The articles and one of the commentaries in this special issue are extensions of that symposium. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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