6M32(51)氮氢气压缩机系统的技术改造

1 机组简介 6M32(51)-190/320-BX型氮氢气压缩机的基础件采用德国博尔格公司的专有技术,具体参数如下: 压缩介质:氮氢气,压缩级数:6级;转速:375rpm;行程:320mm,轴功率:2920kW,容积流量:190m~3/min;气量调节:回路调节,冷却填料润滑油:1.95 kg/h;重量:主机69.45t,     

FINITE ELEMENT ANALYSIS OF THE FLOW INDUCED BY ROTATING BLADES IN AN INCOMPRESSIBLE VISCOUS FLUID

Aerodynamic loads on a multi-bladed helicopter rotor in hovering flight were calculated by solving the three-dimensional incompressible Navier-Stokes equations. The rotor wake effects were accounted by the correction of local geometric angle of attack according to a free-wake modeling in addition to an empirical modification for the tip flow effect. The validity and efficiency of the present method were verified by the comparisons between numerical results and experimental data.     

白石窑水电厂自动运行协联曲线的修正

协联运行曲线是双调机组自动运行时导叶与桨叶的关系曲线,它对机组安全稳定和经济运行起着重要的作用。通过实际运行发现,原协联曲线与实际运行工况存在较大差异,提出了对原协联曲线的修正意见和修正方法,并取得了良好的效果。     

Synthesis of Nearly Monodisperse Iron Oxide and Oxyhydroxide Nanocrystals

Uniform magnetite, hematite, and goethite nanocrystals were prepared through an attractive method based on an oleic acid/alcohol/water system. By adjusting the synthetic parameters (base concentration, alcohol content, categories of alcohols, etc.), the controlled synthesis of uniform magnetite, hematite, and goethite nanocrystals can be easily achieved. Detailed investigations on the effect of the experimental parameters on the morphology of the final products and the phase transitions among the magnetite, hematite, and goethite phases were carried out. Finally, a method of doping other metal ions into magnetite was developed and the magnetic properties of magnetite doped with different metal elements were studied.     

低价态原子簇化合物的紫外-可见光谱研究

对一系列低价态双核原子簇化合物的UV-Vis光谱进行了定性研究，尤其是λ＞300nm处，发现过渡金属的d-d电子跃迁行为，并对个别化合物进行初步量子化学处理．     

井下设备的密封设计应考虑的性能因素

介绍了地层测试器密封设计中常用的材料、影响密封性能的主要因素；定性地论述了井下工具密封设计中应遵循的原则及注意事项。     

高压氮气中自蔓延燃烧合成氮化钛

利用钛粉在高压氮气中的自蔓延燃烧合成（ＳＨＳ），制备了含氮量较高的ＴｉＮ，研究了反应物的松装密度、氮气压的改变与稀释剂的加入对燃烧波蔓延速率和产物转化率的影响，还观察到燃烧方式的改变。     

Arterial oxygen saturation in Tibetan and Han infants born in Lhasa, Tibet

BACKGROUND: Reduced oxygen availability at high altitude is associated with increased neonatal and infant mortality. We hypothesized that native Tibetan infants, whose ancestors have inhabited the Himalayan Plateau for approximately 25,000 years, are better able to maintain adequate oxygenation at high altitude than Han infants, whose ancestors moved to Tibet from lowland areas of China after the Chinese military entered Tibet in 1951. METHODS: We compared arterial oxygen saturation, signs of hypoxemia, and other indexes of neonatal wellbeing at birth and during the first four months of life in 15 Tibetan infants and 15 Han infants at 3658 m above sea level in Lhasa, Tibet. The Han mothers had migrated from lowland China about two years previously. A pulse oximeter was placed on each infant's foot to provide measurements of arterial oxygen saturation distal to the ductus arteriosus. RESULTS: The two groups had similar gestational ages (about 38.9 weeks) and Apgar scores. The Han infants had lower birth weights (2773 +/- 92 g) than the Tibetan infants (3067 +/- 107 g), higher concentrations of cord-blood hemoglobin (18.6 +/- 0.8 g per deciliter, vs. 16.7 +/- 0.4 in the Tibetans), and higher hematocrit values (58.5 +/- 2.4 percent, vs. 51.4 +/- 1.2 percent in the Tibetans). In both groups, arterial oxygen saturation was highest in the first two days after birth and was lower when the infants were asleep than when they were awake. Oxygen saturation values were lower in the Han than in the Tibetan infants at all times and under all conditions during all activities. The values declined in the Han infants from 92 +/- 3 percent while they were awake and 90 +/- 5 percent during quiet sleep at birth to 85 +/- 4 percent while awake and 76 +/- 5 percent during quiet sleep at four months of age. In the Tibetan infants, oxygen saturation values averaged 94 +/- 2 percent while they were awake and 94 +/- 3 percent during quiet sleep at birth and 88 +/- 2 percent while awake and 86 +/- 5 percent during quiet sleep at four months. Han infants had clinical signs of hypoxemia--such as cyanosis during sleep and while feeding--more frequently than Tibetans. CONCLUSIONS: In Lhasa, Tibet, we found that Tibetan newborns had higher arterial oxygen saturation at birth and during the first four months of life than Han newborns. Genetic adaptations may permit adequate oxygenation and confer resistance to the syndrome of pulmonary hypertension and right-heart failure (subacute infantile mountain sickness).     

布正伟新作八人谈——思想与创作共舞：读《创作视界论》谈布正伟先生

作为在高等院校设计院工作的一名建筑师．除埋头设计外，我对理论问题有相当的偏好．这种偏好又带有很强的实用主义色彩。尤其对那些既有精妙设计．又有睿智思想的建筑师很是崇拜．这当然包括设计作品和理论专著文章。而且每每喜欢将作品与理论文章对照着来读，字里行间仿佛看到一个个作品跃然纸上．而实际工程又仿佛在叙述着作者的思想．这种读法令我了解了许多建筑师。然而不难发现．