高温合金GH4169与GH4202在富氧气氛中的燃烧行为

采用富氧燃烧实验方法,通过光学显微镜、扫描电子显微镜和能谱仪等手段对GH4169和GH4202高温合金燃烧试样进行分析,建立合金燃烧质量、热量和氧传输模型,探究两种合金的富氧燃烧机理并提出提高新型高温合金抗燃烧性能的措施.结果表明:GH4202与GH4169合金在富氧条件下均发生燃烧,GH4202抗燃烧性能优于GH4169;两种合金以液相进行燃烧,在合金燃烧前沿存在由未完全燃烧的金属颗粒和氧化物组成\     

GH dependence and GH withdrawal syndrome in GH treatment of short normal children: evidence from growth and cardiac output

BACKGROUND: Cytokines and cytokine receptors are involved in the systemic and local inflammatory response in patients with urinary tract infections. METHODS: We examined urine and serum concentrations of soluble IL-6 receptor (sIL-6R), IL-10 and granulocyte colony-stimulating factor (G-CSF) in 29 women with acute pyelonephritis caused by Escherichia coli 2 weeks after the infection, during the subsequent episode of cystitis or asymptomatic bacteriuria and also later when the same patients were free from bacteriuria. Concentrations of sIL-6R, IL-10 and G-CSF were related to the expression of five virulence markers of E. coli and to glomerular filtration rate (GFR) after pyelonephritis. RESULTS: On admission because of acute pyelonephritis the serum concentration of sIL-6R was similar to that of 12 healthy controls. Two weeks after the infection when all patients had received antibiotic treatment, the serum concentration of sIL-6R was significantly higher compared to that on admission (p < 0.001) and also higher compared to healthy controls (p = 0.001). Patients with increased concentrations of sIL-6R in serum 2 weeks after infection had significantly lower GFR at follow-up (p < 0.05). Patients with acute pyelonephritis had higher concentrations of G-CSF and IL-10 in serum compared to healthy subjects (p < 0.001 and p = 0.06, respectively). G-CSF in serum was higher in patients infected by E. coli producing cytotoxic necrotizing factor (p < 0.05). Patients infected by strains producing hemolysin had lower concentrations of sIL-6R (p < 0.001). Patients with detectable levels of the anti-inflammatory cytokine IL-10 in serum had significantly higher concentrations of IL-6 and the soluble tumor necrosis factor receptors I and II in serum as compared to patients in whom IL-10 was not detectable (p < 0.001, p = 0.001 and p < 0.05, respectively. CONCLUSION: These investigations, together with our previous findings summarized in this paper, contribute to an increased understanding of the local and systemic inflammatory response arising in response to acute pyelonephritis.     

火箭发动机用合金GH202和GH586燃烧事故分析

对GH202、GH586合金部件在高温富氧工况下极短时间内就发生燃烧事故的原因进行了分析。结果表明：合金燃烧的主要原因是环境温度超过了合金的燃烧温度门槛值，而并非材料自身的问题；同时，对如何提高合金的抗燃烧性能及减少燃烧事故提出了建议和措施。     

GH4098合金工艺研究

通过对GH4098合金的柯利布尔实验及不同温度的固溶处理,研究了合金的高温塑性及晶粒长大倾向.探讨了固溶处理温度对合金室温性能的影响.确定了合金的晶粒长大突变温度及理想热变形温度.     

GH150合金棒材的热处理制度

通过组织观察、室温和600℃拉伸试验以及600℃持久性能试验，研究了不同热处理制度对GH150合金棒材组织和性能的影响。研究结果表明，固溶温度对合金组织和性能的作用较为明显。当固溶处理温度较低时，合金的晶粒较小，拉伸性能好，而持久性能较差；而固溶处理温度较高时则与之相反。一次及二次时效处理温度的变化对合金的拉伸性能影响不大，但对持久性能有一些影响。时效处理温度较低时，合金中析出的γ’相、碳化物等较细小、弥散。     

GH169合金的DA处理

用热变形后的直接时效(DA处理)和标准热处理对比试验的方法,对DA处理在GH169合金中的实际应用进行了探讨。结果表明,DA处理确可提高合金的拉伸强度,并大幅度提高光滑持久寿命。但由于塑性指标的降低而导致缺口持久和周期持久寿命的降低,并使疲劳、蠕变交互作用的蠕变损伤加剧。其原因是可能DA处理过程中晶界δ相析出过少,晶界晶内强度配合不良,达不到强韧化的作用。同时指出晶粒细化,并在变形工艺中对位错组态进行控制,使δ相以合理的数量和形态析出,才能获得真正应用的DA GH169合金。     

GH690镍基高温合金的脱硫

在工业化大生产中,从原材料精选到真空感应熔炼加电渣重熔冶炼工艺过程中,采用造渣及加入脱硫剂的方法,将GH690合金中的硫降到12 ppm,提高了合金的加工塑性,并获得了较高的成材率.     

GH4698合金的热处理制度

 在现有GH4698合金热处理制度研究的基础上,提出了两种新型的热处理制度：①去除原有热处理制度中的二次固溶;②采用先低温时效,后高温时效的倒双级时效方法。研究了这两种热处理制度对GH4698合金棒材组织和性能的影响。最终得到了一种新型的适合于GH4698合金的热处理制度：1 000 ℃×8 h,AC(空冷)+650 ℃×20 h,AC+775 ℃×16 h,AC。     

GH4199合金的组织稳定性

采用金相、TEM、相分析等实验手段对GH4199合金长期时效后的组织及其稳定性等进行了研究.结果表明,合金经长期时效处理后,γ'相在700～800℃的析出比较充分,800℃以后开始溶解.在长期时效过程中其长大规律符合Ostwald的成熟理论,同时在700～800℃长期时效有微量σ相析出,700～900℃长期时效以后有微量μ相析出.并且随时效温度的升高μ相的析出时间缩短.     

GH901合金的碳化物偏聚

通过对强碳化物形成元素Ti和Mo在GH901合金中偏析、扩散过程的探讨,得出对GH901合金锻坯进行1200℃均匀化退火,改善锻件中碳化物偏聚的方法.     

Secretion of GH and diabetic retinopathy

Recently it has been studied a possible pathogenetic role of GH in diabetic angiopathy. The purpose of the present study was to verify whether the diabetic retinopathy is associated or not with a high plasma GH level. In an attempt to answer this question we did the dosage of plasma GH after a oral glucose load (110 g), Insulin (0,1 U/Kg) i.v., and arginin i.v. (25 g/30'). The plasma GH measurements were approximately the same as in normal patients. The Authors underline the importance of GH in pathophysiology of diabetic angiopathy and report all recent literature on this argument.     

GH98 合金的热加工性能

通过在Gleeble 1500热模拟试验机上进行的压缩和拉伸试验，研究了GH98合金的热加工-性能，并对其变形组织进行了金相观察。试验结果表明，GH98合金的热加工变形抗力很高，欲改善其热加工性能，加热温度的选择及控制尤为关键。从本试验结果来看，GH98合金的加热温度应严格控制在1000～1200℃，这一点已在实际的锻造和轧制过程中得到验证。     

高铌高磷GH4169C和GH4169合金的组织稳定性

为研究高铌高磷GH4169C高温合金在高温长期时效过程中的组织稳定性,通过场发射扫描电镜和数显布氏硬度计对GH4169和GH4169C两合金分别经600、650、704及720℃时效30~10000 h的显微组织和硬度变化进行对比分析。结果表明：在服役温度（650℃）范围内长期时效,GH4169合金和GH4169C合金均表现优异的稳定性;在服役温度以上长期时效,GH4169合金和GH4169C合金稳定性较差,短时间内,合金组织就出现失稳。对比而言,704℃时GH4169C合金组织稳定性较GH4169合金高,而720℃时GH4169C合金组织稳定性劣于GH4169合金。分析认为,GH4169C合金由于提高Nb含量和P含量使的γ＇相稳定性增加,得以在服役温度以上（704℃）表现比GH4169合金更为优异的组织稳定性,但Nb含量的提高也引起啄相含量的增加,导致组织稳定性下降。在超高温（720℃）下,GH4169C合金稳定性劣于GH4169合金。由此推知,相比GH4169合金,改型GH4169C合金在使用温度上有所提高,但提高有限,在超高温下,其稳定性反而降低。     

Co-expression of bovine growth hormone (GH) and human GH antagonist genes in transgenic mice

Bovine growth hormone (bGH) transgenic (Tg) mice have been shown to possess enhanced growth phenotypes and exhibit severe glomerulosclerosis. One amino acid substitution in GH, i.e. G119R in bGH or G120R in human (h) GH, results in GH antagonists (GHAs). GHA-Tg mice exhibit dwarf phenotypes and normal kidneys. In order to investigate the possibility of GHAs as pharmaceutical agents for the treatment of human diseases with excessive GH levels, we cross bred mice that express bGH with those that express hGHA. Double positive Tg mice were identified that express both genes although at different levels. Kidney histological studies revealed that the double positive Tg mice with high GHA/GH expression ratios possessed normal or near normal kidneys, whereas those with low GHA/GH ratios exhibited glomerulosclerosis similar to GH-Tg mice. Thus, co-expression of GH and GHA genes in vivo results in animal phenotypes and kidney histopathologies which are a reflection of the relative expression levels of each gene.     

Progress in the Research and Manufacture of GH4169 Alloy

GH4169 alloy has been widely used in fields such as aviation, aerospace, and petrochemical, because of its excellent combination of mechanical and processing properties. These properties include good high-temperature strength, excellent creep and fatigue resistance, and good processing and welding performance. The requirement for high performance, high reliability, and long service life of modern engines has led to the incentive to develop GH4169 alloys with improved performance, such as increased temperature-bearing capacity, improved creep endurance, and better fatigue resistance. Advances during the past thirty years in basic research and industrial technology related to GH4169 alloy were systematically summarized, including advances in alloy modification, melting process optimization, and hot deformation technology.     

新型预熔渣电渣重熔GH3128和GH2132合金的研究

研究了一种新型预熔渣电渣重熔GH3128、GH2132合金的钢锭表面质量、易烧损元素的烧损规律。对电渣锭的头尾,从表面到中心进行了Al、Ti等元素的化学分析和光谱扫描。实验结果表明,使用此预熔渣电渣熔炼GH3128、GH2132合金,可以有效的改善钢锭表面质量,并很好的控制合金的Al、Ti元素烧损。     

GH99合金锻棒的研制

介绍了宝山钢铁股份有限公司特钢事业部首次生产GH99合金锻棒的研究工作。通过热力学相图计算制定了2000t快锻机生产GH99合金棒材的终锻温度以及相应的钢锭加热温度,研究了不同加热温度和终锻温度对GH99合金Φ250快锻棒材组织和性能的影响。结果表明,锻棒横低倍组织无缺陷,但是,加热温度和终锻温度过低时,棒材表面会因变形温度低于动态再结晶温度而残留部分原始拉长晶粒。加热温度和终锻温度过高时,因原始晶粒在加热过程中过分长大,边缘处在变形过程中残留部分大的原始拉长晶粒。在合适的加热温度和终锻温度下,棒材的心部、R/2处和表面均获得了均匀且较细小的晶粒组织,在此条件下,合金具有良好的室温、高温综合性能。     

GH4586合金的热加工工艺

主要通过合金不同状态的Gleeble试验、碳化物析出规律以及表面保温试验等一系列工作,研究了GH4586合金的热加工塑性,从而确定了该合金的热加工工艺.