转炉钢渣的胶凝性能和活性激发

分析了转炉钢渣的矿物组成和胶凝性能,研究了Na_2SO_4、CaCl_2、NaCl和海水对钢渣浆体和钢渣水泥浆体强度的影响。结果表明,钢渣粉3d的水化放热量仅为P·O 42.5水泥的7.5%,钢渣浆体7d和90d抗压强度只有0MPa和15.1MPa,所以钢渣粉自身水化能力很低,胶凝性很差。Na2SO_4和CaCl_2对于钢渣浆体有一定的激发效果,掺0.9%Na_2SO_4时激发效果最好,浆体3d和90d抗压强度比不掺激发剂的空白组提高了19.1%和8.2%。对于钢渣水泥浆体,掺1.2%CaCl_2的浆体强度最高,浆体3d和90d抗压强度分别比空白组提高了53.6%和16.9%。NaCl和海水对钢渣浆体和钢渣水泥浆体3d强度有明显的激发作用,但会使90d强度出现较明显的倒缩。     

钢纤维纳米矿粉混凝土劈拉及抗折性能试验研究

在混凝土中同时加入钢纤维和纳米矿粉,对比研究了钢纤维和纳米矿粉掺量以及基体强度对钢纤维纳米混凝土劈拉性能和抗折性能的影响规律。结果表明,钢纤维的加入及增大掺量,改善了试件的破坏特征,劈拉和抗折强度均显著增长;基体强度提高的同时,拉压强度比和折压强度比降低;纳米Si O2和纳米Ca CO3掺量的增大,可小幅度提高劈拉和抗折强度,但脆性也相应提高。钢纤维增强增韧作用、纳米矿粉微填充及促进水化作用共同改善了混凝土的力学性能。     

掺不同纤维的活性粉末混凝土力学性能研究

通过对16组分别掺入钢纤维和聚丙烯纤维的活性粉末混凝土试件进行抗压、抗折强度试验,并且对每组试件采用了三种不同的养护方案。试验结果表明:热水养护对活性粉末混凝土的抗压和抗折强度有较大幅度的提升,当温度达75℃时,提升幅度10%~30%;相比单掺聚丙烯纤维单掺钢纤维对活性粉末混凝土试块的抗压、抗折强度提升幅度更大,钢纤维含量为4%时活性粉末混凝土的抗压和抗折强度分别提高21%和53%;钢纤维掺量为2%和聚丙烯纤维掺量为0.3%并且经过75℃高温养护的活性粉末混凝土试块其抗压、抗折力学性能达到最优,其抗压强度达到168.4MPa,抗折强度达到31.57MPa。     

OVM250钢绞线拉索锚具水密性试验研究

本文主要介绍了OVM250拉索体系产品的水密性试验研究情况,通过对国际三大斜拉索规范PTI2007、fib2005和CIP2002对斜拉索体系产品水密性的试验要求的对比,结合钢绞线斜拉索的实际使用工况,综合考虑了fib2005和CIP2002两大规范对拉索产品水密性试验要求,各种试验参数取两大规范中的高要求,试验水压参数按fib2005要求的3m水压,试验装置按倾斜30度安装和试验周期6个星期按CIP2002规范。因国内外有资质的实验室没有相应的试验设备,OVM公司按确定的试验参数及CIP2002规范试验安装要求设计加工了试验装置并配套试验设备,在国家建筑工程质量监督检验中心及美国CTL实验室的双重见证下进行了水密性试验,并圆满成功,该水密性试验充分验证了OVM250钢绞线拉索锚具的密封可靠性。     

LED电视在2D模式下的视觉健康舒适度测试研究

通过客观量测人眼观视时的各项视觉生理指标,并将各项指标嵌入人眼健康舒适度评价模型进行分析运算。经由583人次的人因实验,从视觉健康舒适度、电视屏幕人眼色觉客观量化反馈以及操控可用性3个方面对12款主流品牌的LED电视样机的视觉健康舒适度与人机交互设计进行了测试与评价。     

Durability studies on steelmaking slag concretes

Electric-arc furnace slag is proposed as a substitute for the conventional aggregate used in classical structural concrete. In the present research is studied the durability of these slag aggregate concretes and their resistance to both physical (freeze–thaw, high temperature and relative humidity) and chemical degradation (sulfate attack, alkali–aggregate reaction and marine environment), as well as their resistance to the corrosion of steel reinforcement bars (an assessment of the risks of corrosion) embedded in the concrete matrix. This approach requires laboratory studies. The main objective of this work focuses on evaluating the durability of slag concrete under the conditions specified in the Spanish structural concrete code. In general terms, the behavior of the concrete with slag aggregate was similar to or better than the reference concrete (natural aggregate), except in case of exposure to marine environments and seawater, which resulted in quicker chloride penetration. The study confirms the viability of producing steel-reinforced concrete with slag aggregate.     

High-temperature corrosion behavior of Ni–50Cr coating deposited by high velocity oxygen–fuel technique on low alloy ferritic steel

Ni–50Cr coatings were deposited using the HVOF technique on low alloy ferritic steel (2.25Cr–1Mo) substrates to improve their performance in high temperature steam environments. Different thermal spray parameters were studied in order to optimize the corrosion resistance of the coatings. High temperature thermal tests at 650 °C in different CO₂ atmospheres (air with 0, 15 and 25 vol.% CO₂) and thermal cycling tests in air at 550 °C and 650 °C were conducted to study the effectiveness of the coating protection system. The uncoated specimens were severely corroded but no oxidation in the coated substrates was detected. A reduction of 10 times in terms of weight change per area unit in the coated steel was obtained after 360 h of testing respect to that of the uncoated steel.     

53例下肢静脉血栓超声临床诊断价值

目的：探讨下肢静脉血栓超声征象特点。方法：回顾性分析超声诊断下肢静脉血栓53例。结果：急性21例,亚急性和慢性共32例;完全栓塞18例,不完全栓塞35例;肌肉内静脉1例、浅静脉血栓9例、深静脉血栓43例;左侧39例、右侧10例、双侧4例;或有低、中等回声团,或有点状、束状血流信号。结论：超声运用二维与彩色多普勒血流信号检测,配合乏氏试验等方法,诊断效用高。     

热浸镀锌大型天线钢结构件的应用研究

热浸镀锌为大型天线的防腐蚀提供了解决方法,本文探讨了天线热浸镀锌存在的问题,并从修改天线结构形式等方面提出了改进的方案,实现了大型天线的热浸镀锌。