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141.
142.
Sulfur in coal causes problems in coal processing and utilization, therefore the chemical beneficiation of coal has gained widespread attention. Using three coal samples with high sulfur content the effect of desulfurization has been studied. For Nantong coal containing 4.25% total sulfur under the condition sulfur reduction increased from 38.8% upto 62.4% the released sulfur was generally sulfate and pyrite, but the organic sulfur almost remained constant. When alkali treatment was performed at 370°C, organic sulfur removal of Donglin and Yanzhou coal was to 50.6% and 57.3% respectively. 相似文献
143.
Increased use of titanium alloys as biomaterials is occurring due to their lower modulus, superior biocompatibility and enhanced corrosion resistance when compared to more conventional stainless steels and cobalt-based alloys. These attractive properties were a driving force for the early introduction of alpha (cpTi) and alpha + beta (Ti-6A1-4V) alloys as well as for the more recent development of new Ti-alloy compositions and orthopaedic metastable beta titanium alloys. The later possess enhanced biocompatibility, reduced elastic modulus, and superior strain-controlled and notch fatigue resistance. However, the poor shear strength and wear resistance of titanium alloys have nevertheless limited their biomedical use. Although the wear resistance of beta-Ti alloys has shown some improvement when compared to alpha + beta alloys, the ultimate utility of orthopaedic titanium alloys as wear components will require a more complete fundamental understanding of the wear mechanisms involved. This review examines current information on the physical and mechanical characteristics of titanium alloys used in artifical joint replacement prostheses, with a special focus on those issues associated with the long-term prosthetic requirements, e.g., fatigue and wear. 相似文献
144.
We examined the effects of different cytokine combinations and culture conditions on the expansion and modulation of cell surface antigens of CD34+ derived dendritic cells (DCs), the most efficient antigen-presenting cells capable of stimulating resting T cells in the primary immune response. Cells with a dendritic morphology and expressing HLA-DR, CD1a, S100 and CD83 were maximally expanded under serum-free conditions with the addition of SCF, GM-CSF, TNF-alpha, TGF-beta and Flt-3 ligand (fold increase of CD1a+ cells = 102 +/- 32 after 2 weeks of culture). CD34+ cells were also grown under continuous flow conditions in an artificial capillary system: after 14d of culture, the expansion in the total cell number was lower than that of the static cultures (3.3 +/- 2 v 18.9 +/- 4) but the percentage of CD1a+/CD83+/ CD80+ cells was considerably higher, whereas the CD14+ cells were significantly reduced (8.9 +/- 2 v 26 +/- 13). In continuous perfusion cultures, low levels of DC precursors and of LTC-IC were still present up to day 14. The DCs generated under flow conditions stimulated the mixed leucocyte reaction (MLR) more than the cells grown in static cultures. By electron microscopy, cells grown in the continuous flow system showed an increased number of large cells with numerous dendritic processes and abundant multilamellar complexes. The cells expanded under these conditions were sorted on the basis of their light-scatter properties into two fractions: one containing a predominance of CD1a+/S100+/ CD8 3+/CD80+/CD14- 'large cells' with great internal complexity (mature DCs); the second including 'small cells' either CD33+/CD14+, CD33+/CD15+ or CD33+/CD13-/CD14. The DCs generated and selected with this method are therefore particularly well suited for immunotherapeutic protocols. 相似文献
145.
陶瓷模用α半水石膏的研究 总被引:1,自引:0,他引:1
理论上提出了影响陶瓷模用半水石膏常,高温性能的主要因素,即结晶形态.标准稠水度,初凝时间,抗折强度,进行了实验验证,确定了相应的制作技术,获得了性能优良的陶瓷模用α半水石膏。 相似文献
146.
147.
Waveguide stacks of GeSiO2-based glass deposited on Si exhibit a permanent second-order nonlinearity following temperature electric-field poling. High temperature hydrogen loading increases the second harmonic signal under certain conditions 相似文献
148.
149.
分析聚酯固相装置原料温度在工艺系统过程中存在的问题,介绍6820反应器的温度控制优化方案,给出为改善系统反应温度控制的方案设计和组态内容。 相似文献
150.