SiC颗粒增强铝基复合材料切削表面分形维数及其与抗磨损性能的关系

做为一种耐磨性能很好的材料 ,SiC颗粒增强铝基复合材料切削加工表面具有分形特征。实际研究表明SiC颗粒增强铝基复合材料切削加工表面分形维数与抗磨损性能有密切关系 ,本文还分析了表面分形维数越大其抗磨损性能越强的机理。     

论体育游戏在高校健康教育中的作用

健康教育是高校育人的任务之一。通过体育游戏进行身心健康教育,趣味性强,容易开展,效果好。     

Synthesis and characterization of poly(siloxane-urethane)s

A series of polyurethane block copolymers based on hydroxy-terminated polydimethylsiloxane and poly(propylene glycol) soft segments of molecular weights 1818 and 2000, respectively, were synthesized. The hard segments consisted of 4,4′-diphenylnethane diisocyanate and 1,4-butanediol as the chain extender. Samples with different molar ratios were prepared. We tried to synthesize polydimethylsiloxane-based polyurethanes (PDMS-PU) containing a hard block as major fraction and a soft block as minor fraction for preparing toughened rigid systems. After a study of the pure polydimethylsiloxane-based polyurethane and poly(propylene glycol)-based polyurethane (PPG-PU), (mixed polyol)-based block copolymers and blends of PDMS-PU and PPG-PU were synthesized, and characterized by means of differential scanning calorimetry, tensile testing and scanning electron microscopy. In (mixed polyol)-based copolymers and lower hard-segment content blends, macro-phase separation occurred, but blends with higher hard-segment contents showed significant reduction in amounts of phase separation.     

“镍”催化酰氯和有机锡试剂交叉偶联反应的研究

镍络合物催化酰氯与有机锡试剂交叉偶联合成有机酮的反应,其反应选择性强,反应彻底,转化率高,工艺简单。在有机锡过量的情况下,对不同催化剂的催化活性和包括投料比,反应温度,反应时间,反应溶剂等反应条件进行了考察。     

The effects of plasma etching induced gate oxide degradation onMOSFET's 1/f noise

The effects of the plasma etching process induced gate oxide damages on device's low frequency noise behavior are investigated on MOSFET's fabricated with different field plate perimeter to gate area ratio antennas. Abnormal 1/f noise spectrum with a shoulder centered in the frequency range of 100 and to 1 kHz was frequently observed in small geometry devices, and it is attributable to a nonuniform distribution of oxide traps induced by plasma etching process     

能量"三环节"理论在原油蒸馏装置扩能改造中的应用

中国石化扬子石化股份有限公司炼油厂在第一套常减压蒸馏装置扩能改造中，使用了多项节能技术以实现能量的优化利用。本文以标定数据为基础，运用能量“三环节”理论对该装置的用能状况进行了计算和分析，从能量利用角度对装置的扩能改造效果进行了评价，并为装置的进一步优化能量利用提出了相应措施。     

RANCIDITY OF WALNUTS AND ALMONDS AFFECTED BY SHORT TIME HEAT TREATMENTS FOR INSECT CONTROL

Short time heat treatments effectively control insect contamination of nuts containing substantial quantities of polyunsaturated fatty acids susceptible to oxidative rancidity. Walnut kernels contain greater concentrations of polyunsaturated fatty acids than almond kernels. The objectives of this research were to investigate the lipid stability of shelled walnuts and almonds as affected by short time heat treatments and accelerated storage temperatures. Heating treatments were at 55C for 2 min, 55C for 10 min, 60C for 2 min or 60C for 10 min to simulate predetermined deinfestation treatments. Untreated control and heat treated shelled walnut and almond kernels were stored at 25C for 5, 15, 30 and 60 days or 35C for 2, 5, 10 and 20 days to simulate the shelf lives of walnut and almond kernels at 4C for 2 years. Oils extracted from untreated and short time heat treated walnut kernels exhibited higher peroxide values than oils extracted from untreated and short time heat treated almond kernels under equivalent conditions. Oils extracted from untreated walnut kernels exhibited significantly (P ± 0.05) higher peroxide values than oils extracted from short time heat treated walnut kernels after 5, 15, 30, and 60 days of storage at 25C, or after 2, 5, 10, or 20 days of storage at 35C. Oils extracted from untreated almond kernels exhibited higher peroxide values than oils extracted from short time heat treated almond kernels after 5, 15, 30, or 60 days of storage at 25C, or after 2, 5, 10 or 20 days of storage at 35C. Oils extracted from untreated walnut kernels and oils extracted from short time heat treated walnut kernels exhibited higher peroxide values than oils extracted from almond kernels after storage at 25C or 35C. Short time heat treatment does not enhance development of rancidity during accelerated storage of walnut or almond kernels.     

混凝土芯砂石桩复合地基加固堤防软基试验研究

介绍了一种新型的地基处理方法——混凝土芯砂石桩复合地基法及其在水利防洪堤软基加固工程中的应用情况。通过现场原位观测和试验,研究了混凝土芯砂石桩复合地基固结变形、孔压消散、桩土应力分担及承载力特性,结果表明混凝土芯砂石桩强度高,排水固结能力强,能迅速提高桩间土强度和承载力,应用于水利堤防工程既能控制堤防深厚软基的工后沉降,又能提高堤防边坡的稳定性,推广应用前景良好。     

砂岩储集层微波加热产生微裂缝的机理及意义

微波加热无需介质传热,具有升温速度快、热惯性小、选择性加热、穿透力强、过程易于控制等优点,已被试验性地应用于石油开采中。但有关微波加热对储集层岩石微观结构影响的研究还很缺乏,限制了该项技术在油气开采领域的广泛应用。通过实验手段研究了微波加热前后砂岩岩样微观结构变化、微裂缝产生机理及特征。结果表明,砂岩在微波加热过程中容易产生微裂缝,且不同岩石的微波加热致裂机理不尽相同,主要包括:矿物失水收缩、颗粒粒间开裂和颗粒内部开裂,低渗透致密砂岩刚性颗粒的粒内开裂作用显著。微波加热产生的微裂缝具非定向特征,即使在应力的作用下有一部分裂缝会发生闭合,但仍有大量微裂缝可以起到增加渗透率的作用。井下微波加热的致裂作用有助于改善近井区域渗流能力,提高低渗透油气藏的开采效率。图4参15