氯氧化锆的放射性分析

氯氧化锆的放射性由主要生产原料锆英砂带入。产地不同,锆英砂放射性相差较大。通过统计分析,对几个主要产地的锆英砂和其制品氯氧化锆的放射性进行比较研究。锆英砂比活度控制在一定范围内时,不同产地的锆砂所产出氯氧化锆,其放射性基本相似,没有明显的差异。     

我国锆砂生产贸易点评

报告和点评了我国锆砂进出口、生产、消费、价格和应用等方面的情况和问题。我国锆砂进口的多,出口的少。2005年进口锆砂达34.99×104t,创历史新高,出口仅万吨以下。进口的国家主要有澳大利亚、南非、印度尼西亚和越南等。我国锆砂主要应用于钢铁、玻壳、化学制品和耐火材料等。我国锆砂总消费量超过40×104t,取代欧洲成为世界最大的锆砂消费国。2004年国内锆砂价格飞涨至12500元/t;2005年回落到8500元/t。建议制定锆砂的钍、铀含量和放射性的安全标准。随着经济快速发展,我国对锆砂的需求仍将以3%的速度增长。     

近两年我国锆英砂及其精矿进口情况分析

介绍了2005年、2006年及2007年1￣4月我国锆英砂及其精矿的进口情况。2006年,我国累计进口锆英砂374649t,与2005年的340995t相比增长了9.9%,主要从澳大利亚、南非、越南和印尼等国家进口。2006年,我国从印尼进口锆英砂的量急剧增加,达到124855t,进口量仅次于澳大利亚。进口的港口主要集中在上海、海口、南宁、湛江等口岸。从2007年1￣4月的进口情况看,进口量呈上升趋势,增幅达到22.8%。预计2007年我国锆英砂的进口量(折合成精矿量)将比2006年增加(3.0￣3.5)×10~4t。     

用碱分解锆英砂制备ZrO2工艺中放射性的分布、处理和回收研究

研究和检测用氢氧化钠分解锆英砂制备ZrO2工艺过程的放射性的走向分布。结果表明，在工业ZrO2的生产工艺中，U和Th主要富集于废酸和ZrOCl2的母液中，也分散于硅渣和水洗液中；两者放射性超标，经转化和处理之后达到排放和堆放要求，并可利用做建筑材料；废酸和母液可以通过TBP萃取分离和回收U和Th，具有工业和经济价值；处理工艺是可行和有效的；废液经沉淀处理之后，沉渣和上清液都达到国家排放和堆放的标准。     

镁—钇—锌—锆系铸造合金热强性能的研究

镁-钍系合金以适于300℃高温下长期使用的抗蠕变合金著称。但钍具有放射性,故该合金并不令人满意。 近年来,曾有钇对镁合金热强性能具有良好作用的报导。笔者在分析有关文献,探索镁-钇-锆、镁-钇-锌-锆和镁-钇-钕-锌-锆等系的热强性能后,确定对镁-钇-锌-锆系合金在300℃下的性能进行详细研究。本文主要目的是讨论钇和锌在一较宽范围内,其含量变化对合金性能及其组织结构之间的相互关系。     

用磁选机分选铝土矿的冶炼残渣

铝工业用拜耳法生产氧化铝,产出具有一定价值的铝土矿残渣(赤泥和砂)。表1中列出了这种残渣中元素含量的大致范围。各种元素按含量多寡排列。这类残渣的可能用途之一是制砖。但是铀和钍的衰变产物能级相当高,以致于成为引人注目的难题。另外,残渣虽含有大量的铁,但钠和硅酸盐的污染程度却妨碍其产出物直接焙烧。因此,要研究确定有前途的处理残渣的经济办法:1)除去硅酸盐部分中放射性成分的污染,使之能安全地用作建筑材料;     

南方离子型稀土中铀和钍的放射性调查及萃取分离

针对南方离子型稀土中铀、钍的放射性水平开展了调查,并根据南方离子型稀土生产过程中放射性元素铀、钍的分布、走向规律特点,首次提出采用环烷酸萃取剂预先萃取分离浸矿原液中的铀、钍。考察料液酸度、萃取相比、萃取时间、萃取剂皂化度及萃取级数对萃取的影响规律,并对反萃实验进行研究。实验表明:REO=1.75mol/L的稀土料液,采用15%环烷酸+15%异辛醇+70%磺化煤油(体积分数)萃取剂体系,在最佳萃取条件下:料液酸度pH为1.0~3.5,萃取时间10 min,萃取相比O/A=2:1,采用边萃取边皂化方式,按6 mL/min速度加入0.6 mol/L NaOH溶液(V_(NaOH):V_(extractant)=1:100)单级铀萃取率达98.6%,钍萃取率达33.3%,负载有机相采用5 mol/L盐酸按相比(O/A)20:1三级逆流反萃,铀、钍反萃取率均达100%。     

美国、日本生产五个“9”的超纯铝和超纯钛

美国铝业分司采用已获得专利的一项提纯新工艺开始工业规模地生产集成电路广泛使用的五个“9”以上的超高纯铝,成为美国第一家超纯铝生产和供应厂商。该公司所生产的超纯铝,其成分不同于欧洲和远东一些铝生产厂商供应的铝,其铀和钍的含量极抵。采用结晶提纯的新技术将铀、钍和其它有害杂质去除到集成电路制造厂家可以接受的水平。美国铝业     

锆英砂供求平衡预测

2004年世界锆英砂需求,当初预测有7.4×104t 的供应不足,但实际数字为5×104 t。目前锆英砂的需求主要是亚洲,特别是中国,但受生产不足以及包括流通在内的库存见底的影响,使得2004年世界锆英砂需求量达114.2×104t,比前一年增长0.8%;且在生产方面,澳大利亚、南非的减产部分由于被美国等其它地域的增产部分所弥补,锆英砂存在的供求间隙在逐渐减小。     

滴定量热法研究协萃反应热力学

摘要微量量热技术结合计算机自动控制及数据处理程序,为研究多元络合反应及协同萃取机理提供了新的精确、快速方法.滴定量热法通过测量反应计算反应的热力学函数.本文用量热滴定比较了中性配体TBP、TOPO、N503与铀、钍的TTA络合物在甲苯溶液中协萃能力大小;同种配体与铀、钍不同的β二酮TTA与PMBP配合物的反应能力;并将铀、钍、钕、钇在PMBP-TOPC体系的萃取平衡数据与滴定量热结果作了比较和讨论     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

THERMODYNAMICS STUDY ON THE DECOMPOSITION OF CHROMITE WITH KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

INFLUENCE OF HEAT TREATMENT ON DAMPING BEHAVIOUR OF THE MAGNESIUM WROUGHT ALLOY AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

An Easy Way to Quantify the Adhesion Energy of Nanostructured Cu/X(X=Cr,Ta,Mo,Nb,Zr) Multilayer Films Adherent to Polyimide Substrates

An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quantitatively estimate the interfacial energy of the nanostructured multilayer films(NMFs) adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be *5.0 J/m2 for Cu/Cr, *4.1 J/m2 for Cu/Ta,*2.8 J/m2 for Cu/Mo, *1.1 J/m2 for Cu/Nb, and *1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.     

High-Speed Friction Stir Welding of SiC_p/Al–Mg–Si–Cu Composite

A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.