大功率机车用轴流冷却风机叶轮的改进设计

大功率电力机车发动机用冷却风机是保证机车运行安全的重要设备,但目前国内该类车用冷却风机主要依赖进口.论文在一维设计基础上,通过三维数值软件 NUMECA 对某大功率8轴机车用轴流冷却风机叶轮进行方案分析并改进设计,获得了性能较好的叶轮模型.在满足外形尺寸不变及限制功率的前提下,降低转速和流量,实现了出口风压相对提高并改善了效率,该冷却风机已装车运行.     

首钢矿业公司烧结厂实施小球烧结技术

该厂和北京钢铁研究总院联合开发的小球烧结新技术,以强化混合制粒、燃料分加、提高混合料温度为主要特征,实现了低温烧结.表面点火温度降低150℃以上,每吨烧结矿点火重油消耗降低0.5 kg以上,烧结过程温度降低100℃左右,燃料消耗降低8 kg/t以上,台车料厚提高到650～ 700 mm左右.经过完善和创新,对于改善成品矿质量,降低消耗发挥了突出作用,收到了显著的经济效益,电耗降低10kW*h/t以上,烧结机利用系数提高10%以上,成品矿运输到北京末子降低5%以上.     

Study on parameters of L-[1-13C]phenylalanine breath test for quantitative assessment of liver function in healthy subjects and patients with hepatitis B virus-related liver disease

1 Introduction Hepatitis B virus-related liver disease is the most common hepatopathy around the world, especially in developing countries like China, which brings more and more increasing healthy and social burden. To measure liver function accurately is critical for moni-toring the progression of liver dysfunction; evaluating the effect of treatment; predicting long term prognosis and risk of surgical interventions and optimal timing of liver transplant. But in clinic, there are few routine…     

L－抗坏血酸棕榈酸酯的合成

以Ｌ－抗坏血酸和棕榈酸为基本原料，通过棕榈酰氯中间产物，在Ｌ－抗坏血酸的第六位碳上酯化。总产率７２．５％，产品红外光谱、￣（１３）Ｃ谱符合文献值，理化测试数据符合美国药典ⅩⅩⅡ版标准。     

Tensile properties and fracture characteristics of spray cast alloy IC6 （Ni-7.8Al-14Mo-0.05B）

Tensile testing results of spray cast Ni3Al-based superalloy indicated that the yield strength and tensile strength increase with the increasing of temperature and reached maximum at around 760℃, then decrease with the increasing of temperature. After high temperature isostatic pressing (HIP), yield strength decreased and ductility and tensile strength increased. Stereographic projection showed that no matter at room temperature, medium temperature or high temperature, cracks extend along (111).     

A UNIVERSAL ANALYTIC POTENTIAL-ENERGY FUNCTION BASED ON A PHASE FACTOR

Using a field equation with a phase factor, a universal analytic potential-energy function applied to the interactions between diatoms or molecules is derived, and five kinds of potential curves of common shapes are obtained adjusting the phase factors. The linear thermal expansion coefficients and Young‘s moduli of eleven kinds of fuce-centered cubic (fcc) metals - Al, Cu, Ag, etc. Are calculated using the potential-energy function; the computational results are quite consistent with experimental values. Moreover, an analytic relation between the linear thermal expansion coefficients and Young‘s moduli of fcc metals is given using the potential-energy function. Finally, the force constants of fifty-five kinds of diatomic moleculars with low excitation state are computed using this theory, and they are quite consistent with RKR (Rydberg-Klein-Rees) experimental values.     

Corrosion of two kinds of cast steels containing chromium in hot concentrated alkaline

A typical hot concentrated alkaline corrosion environment exists in alumina metallurgical industry, so that steel materials with outstanding alkaline corrosion resistance are strongly demanded for its processing equipment. In this paper, the corrosion resistance of two kinds of martensitic cast steels containing chromium in static 303g/L NaOH alkaline solution at 85℃ was studied through polarization and potential-time curves, corrosion weight loss and corrosion morphology analysis. Experimental results showed that protection effect by passive film of cast steel containing Cr was temporary. The low carbon steel without Cr content also exhibited chemical passivity in the same solution. The corrosion mode of the tested Cr-containing cast steel was composed of active dissolving corrosion and caustic embrittlement cracking. Dissolving corrosion was the primary mechanism for the induced weight loss, while severe caustic embrittlement cracking was secondary. With the increase of chromium content in the cast steel, the tendency of the caustic embrittlement cracking decreased, while the active dissolving corrosion increased.     

Microstructure refinement of Sn-Sb Peritectic alloy by power ultrasonic

Sn-Sb peritectic alloy was treated with 400 W, 600 W and 800 W ultrasonic, respectively, to study the effect of power ultrasonic on solidification microstructure. Results show that power ultrasonic can refine α phase and β phase of the alloy, as well as eliminate gravitational segregation. Moreover, 600 W ultrasonic demonstrated the best refining effect, not only homogenous and fine solidification microstructure can be obtained, the cubical β phase crystals can also be spheroidized.     

INFLUENCES OF TRACE ADDITIONS OF STRONTIUM AND PHOSPHORUS ON ELECTRICAL RESISTIVITY AND VISCOSITY OF LIQUID Al-Si ALLOYS

ＩＮＦＬＵＥＮＣＥＳＯＦＴＲＡＣＥＡＤＤＩＴＩＯＮＳＯＦＳＴＲＯＮＴＩＵＭＡＮＤＰＨＯＳＰＨＯＲＵＳＯＮＥＬＥＣＴＲＩＣＡＬＲＥＳＩＳＴＩＶＩＴＹＡＮＤＶＩＳＣＯＳＩＴＹＯＦＬＩＱＵＩＤＡｌＳｉＡＬＬＯＹＳ①ＧｕｉＭａｎｃｈａｎｇ，ＪｉａＪｕｎ，...