AOD炉倾动力矩计算及重要构件强度分析

为明确36 t AOD炉在不同转角情况下倾动力矩及其重要结构件的强度,应用solidworks实体建模软件建模并确定在不同转角时炉内的钢液及炉壳体和砖层所构成的结构重心位置,并以此为依据,进行倾动力矩的计算,得到了倾动力矩的变化曲线,得到了在AOD炉转角为45°~75°时具有较大倾动力,最后对AOD炉重要构件托圈的强度...     

石墨烯增强铝基复合材料制备技术研究进展

石墨烯具有独特的结构特点和优异的物理化学性能,是理想的复合材料增强体。本文综述了石墨烯增强铝基复合材料制备方法的现状,着重介绍了石墨烯的分散工艺和复合材料的成型方法,讨论了这些方法对复合材料性能的影响,并从混粉和烧结工艺方面提出了石墨烯增强铝基复合材料制备方法的发展方向。     

Permeability of blood-eye barrier in patients with primary glaucoma combined with lens opacity

The paper focuses on the history and sources of origin of sanology as science, with its brief characterization being given, relating to such items as definition, object and subject of investigation, methodological approaches and tasks, with special emphasis being placed on the significance of sanology in the elaboration of general theory of medicine.     

Thought suppression produces a rebound effect with analogue post-traumatic intrusions

Attempts to suppress traumatic material may be involved in the development and maintenance of post-traumatic stress disorder (PTSD). In order to investigate this possibility, analogue post-traumatic intrusions were induced in normal participants by means of a distressing film. For comparison, a second film was used to induce intrusions about polar bears. It was hypothesized that the suppression of these intrusions would produce an immediate decrease but a delayed increase ("rebound effect") in their frequency. It was also predicted that the rebound effect would be larger for the analogue traumatic intrusions. Each film was followed by two consecutive time periods during which participants' thoughts were recorded. During the first period, the suppression group was instructed to suppress thoughts about the film whilst the control group merely recorded their thoughts. During the second period, both groups merely recorded their thoughts. The results supported the immediate decrease hypothesis for both types of intrusion. As predicted, there was a rebound effect for analogue traumatic intrusions although not for polar bear thoughts. Several methodological issues relating to the findings are highlighted. The possible implications of a rebound effect with trauma-relevant intrusions are discussed with reference to PTSD.     

An alternative route for multistep tumorigenesis in a novel case of hereditary renal cell cancer and a t(2;3)(q35;q21) chromosome translocation

Through allele-segregation and loss-of-heterozygosity analyses, we demonstrated loss of the translocation-derivative chromosome 3 in five independent renal cell tumors of the clear-cell type, obtained from three members of a family in which a constitutional t(2;3)(q35;q21) was encountered. In addition, analysis of the von Hippel-Lindau gene, VHL, revealed distinct insertion, deletion, and substitution mutations in four of the five tumors tested. On the basis of these results, we conclude that, in this familial case, an alternative route for renal cell carcinoma development is implied. In contrast to the first hit in the generally accepted two-hit tumor-suppressor model proposed by Knudson, the familial translocation in this case may act as a primary oncogenic event leading to (nondisjunctional) loss of the der(3) chromosome harboring the VHL tumor-suppressor gene. The risk of developing renal cell cancer may be correlated directly with the extent of somatic (kidney) mosaicism resulting from this loss.     

Prognostic value of alpha 6 beta 4 integrin expression in breast carcinomas is affected by laminin production from tumor cells

Familial erythrocytosis, associated with high haemoglobin levels and low serum erythropoietin (Epo), has been shown to co-segregate with a sequence repeat polymorphism at the 5' region of the erythropoietin receptor (EpoR) in a large Finnish family. We have investigated the cause of erythrocytosis in an English boy. Sequencing of the cytoplasmic region of the EpoR detected a de novo transition mutation of G to A at nucleotide 6002. This mutation resulted in the formation of a stop codon at amino acid 439 with the loss of 70 amino acids from the carboxy terminus. The mutation (G6002A) has arisen independently in a Finnish family and de novo in this English boy. Patients with unexplained erythrocytosis and low serum Epo levels should be investigated for EpoR mutations.     

Smoothness maximization along a predefined path accurately predicts the speed profiles of complex arm movements

The speed profiles of arm movements display a number of regularities, including bell-shaped speed profiles in straight reaching movements and an inverse relationship between speed and curvature in extemporaneous drawing movements (described as a 2/3 power law). Here we propose a new model that simultaneously accounts for both regularities by replacing the 2/3 power law with a smoothness constraint. For a given path of the hand in space, our model assumes that the speed profile will be the one that minimizes the third derivative of position (or "jerk"). Analysis of the mathematical relationship between this smoothness constraint and the 2/3 power law revealed that in both two and three dimensions, the power law is equivalent to setting the jerk along the normal to the path to zero; it generates speed predictions that are similar, but clearly distinguishable from the predictions of our model. We have assessed the accuracy of the model on a number of motor tasks in two and three dimensions, involving discrete movements along arbitrary paths, traced with different limb segments. The new model provides a very close fit to the observed speed profiles in all cases. Its performance is uniformly better compared with all existing versions of the 2/3 power law, suggesting that the correlation between speed and curvature may be a consequence of an underlying motor strategy to produce smooth movements. Our results indicate that the relationship between the path and the speed profile of a complex arm movement is stronger than previously thought, especially within a single trial. The accuracy of the model was quite uniform over movements of different shape, size, and average speed. We did not find evidence for segmentation, yet prediction error increased with movement duration, suggesting a continuous fluctuation of the "tempo" of discrete movements. The implications of these findings for motor planning and on-line control are discussed.     

Blood reinfusion during nephrectomy in patients with kidney neoplasm'

Reinfusion of autologous blood in 22 patients with cancer of the kidney was used during nephrectomy. Intraoperative blood loss made up 1000-4000 ml (20-80% VCB). 800-3600 ml of blood was collected from the operation wound and reinfused. In spite of massive blood loss, 20 patients recovered. Lethal outcomes (2 patients) were not caused by blood reinfusion. In 19 patients of control group with renal cancer massive blood loss was compensated by preserved donor blood transfusion. It is shown that reinfusion of autologous blood promotes more stable hemodynamics during the operation, reduces the quantity of postoperative complications and lethal outcomes, provides qucker restoration of morphologic structure of the blood and results in less substantial changes in filtration of a single kidney. There were no statistically significant differences in 5-year survival rate of patients in the study (40.9%) and control (42.1%) groups, nor in the frequency of hematogenous metastasizing of cancer. Because blood reinfusion does not increase the risk of hematogenous metastases of cancer, it is not contraindicated in massive blood loss during nephrectomy in patients with renal cancer.