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61.
文章介绍了宝钢自备电厂在改善锅炉燃烧工况,控制锅炉水冷壁结焦所采取的技术措施,分析了锅炉水冷壁结焦量与锅炉二次再热器烟气出口平均温度的关系,为解决锅炉水冷壁结焦所引发的二次再热器超温爆漏问题提供了依据。  相似文献   
62.
63.
Lightly p-doped (3×1017 cm-3) GaN grown on GaAs substrates by metal organic molecular beam epitaxy (MOMBE) shows deactivation of the residual acceptors on exposure to a microwave (2.45 GHz) hydrogen plasma at 250°C. Subsequent annealing to 350°C produces further dopant passivation, while higher temperatures (450°C) restore the initial conductivity. These results suggest that hydrogen carrier gases should be avoided during vapour phase growth of III-V nitrides  相似文献   
64.
BACKGROUND: Tissue plasminogen activator (tPA) is elevated in cancer patients and is thought to promote tumor angiogenesis by facilitating endothelial cell migration through plasmin-mediated degradation of extracellular matrix. Due to the presence of an epidermal growth factor (EGF)-finger domain in the tPA A-chain and the existence of an endothelial cell (EC) receptor that binds this domain, it was hypothesized that tPA has a direct receptor-mediated effect on EC proliferation, independent of plasmin. METHODS AND RESULTS: Using cultured canine ECs, tPA (7.25 microg/ml, approximately 107 nM) increased proliferation as much as 50 and 170% in the absence and presence of growth factors, respectively. tPA-induced increases in EC proliferation occurred independent of plasmin generation, as the plasmin inhibitor, aprotinin (10 microg/ml) did not inhibit tPA-induced proliferation. However, tPA-induced proliferation was inhibited dose-dependently to a maximum of 78% using a monoclonal antibody against the tPA EGF-finger domain. This antibody, known to inhibit tPA binding to its receptor, did not inhibit tPA-induced plasmin generation. To investigate the role of potential signal transduction pathways, ECs were exposed to lavendustin A, a tyrosine kinase inhibitor, at 33.5 microM (IC50 for basic fibroblast growth factor). Lavendustin A did not inhibit tPA-induced EC proliferation. However, Rp-cAMP, an inhibitor of cAMP-dependent kinases, specifically inhibited tPA-induced EC proliferation in a dose-dependent manner (IC50 = 50.5 microM). Pertussis toxin at maximal concentrations for this system (0.5 ng/ml) did not inhibit tPA-induced EC proliferation. CONCLUSION: These results lend support to the hypothesis that tPA may have a direct receptor-mediated effect on EC proliferation and that this effect occurs independent of plasmin and may be dependent upon protein kinase A activity.  相似文献   
65.
Thirty six patients of pulmonary or nasopharyngeal carcinoma were treated with Xilixin granule (XLXG) combined with radiotherapy and compared their efficacy with that of 31 patients treated by Zhenqi Fuzheng granule combined with radiotherapy for control. Results showed that the symptoms of Yin Deficiency syndrome in treated group were obviously improved, the leucocyte decreased by 5.6%, while in control group it reached 25.8%, the 3 year survival rate was significantly higher in treated group (75.0%) than that in control group (51.6%). Animal experiment revealed that XLXG had the effects of tumor inhibition, it could increase white blood cells, platelets and hemoglobin of patients, especially in using large dosage. These results suggested that XLXG have some protective effect against radiotherapeutic damage in patients with malignant tumor.  相似文献   
66.
介绍了用于薄板残余应力测量的新方法——孔径法,该方法是通过测量冲孔直径的变化来间接求出各方向的残余应力;文中详细阐述了残余应力的标定方法;由于可针对不同材料建立了被测材料的平均应力(σ_l)与被测板材宽度(B)、厚度(H)以及冲孔后直径变化率(△D_i/D)之间的数学模型,因而使薄板残余应力测量变得简便而经济;此外还对该方法的分辨率与测量精度进行了实验、计算与分析。  相似文献   
67.
Silver has been previously added to the melt-textured YBa2Cu3O7?x in order to increase the critical current density (J c ) of these materials. However, the effect of this addition on theJ c is presently unclear. The purpose of this study is to investigate the effect of silver on both critical current density and the microstructure of the melt-textured YBa2Cu3O7?x superconductors by means of X-ray diffraction, optical polarized microscopy, and transmission electron microscopy (TEM). TheJ c of the MTG YBCO/Ag samples is more than 104A/cm2 under the 5 kOe magnetic field. It has been shown that as the concentration of silver increases, the fraction of the 211 phase dispersed within the 123 matrix decreases. Therefore, theJ c slightly decreases. These results, together with the effect of the 211 phase, dislocations, and other structure defects on flux pinning, are described in this paper.  相似文献   
68.
The ion energy during electron cyclotron resonance (ECR) plasma hydrogenation is found to have a strong effect on both the effective diffusivity and solubility of hydrogen in n+ and p+ GaAs. For fixed plasma exposure conditions (30 min, 250°C) the diffusion depths for -150 V acceleration voltage are ~50 and ~100% larger, respectively, in p+- and n+-GaAs compared to 0 V acceleration voltage. The smaller incorporation depths at lower ion energy coincide with much larger peak hydrogen concentrations and higher apparent thermal stability of passivated dopants  相似文献   
69.
关于生物系统超微弱发光的实验研究   总被引:3,自引:0,他引:3  
刘颂豪  张有 《激光与红外》1992,22(2):12-16,25
生物系统存在超微弱光子辐射现象。通过一系列实验研究,我们认为,这种光子辐射既有低水平化学发光的性质,又有受激辐射的性质,是受激的低水平化学发光。  相似文献   
70.
The use of rapid isothermal processing (RIP) is detailed for each of the three annealing steps in the fabrication of heterostructure-based devices such as heterojunction bipolar transistors (HBTs). RIP can be used for the alloying of ohmic metal contacts, annealing of ion-bombarded regions for device isolation or parasitic capacitance reduction, and for conventional implant activation annealing. High-speed (fT=65 GHz) HBTs were achieved using RIP for all of the required heating steps. The authors compare the use of several types of silicon carbide-coated graphite susceptors for eliminating slip formation on 2- and 3-in-diameter GaAs wafers during high-temperature implant activation annealing  相似文献   
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