氢氧化铝分解技术

引言自从1911年原拜耳法专利权消失以后,世界绝大多数氧化铝都是用拜耳法生产的。但直到50年代末,由于所用铝土矿的组成,能源价格和所用电解槽设计的不同,拜耳法一直用两种不同的工艺条件生产。“欧洲”拜耳法在用高温、高苛性碱浓度溶出和氢氧化铝分解的产出率高达60克/升以上的条件下,生产细粒、高温焙烧的粉状氧化铝。“美国”拜耳法     

用爆炸法消除残余应力的机理

本文着重分析用表面线状药包爆炸消除残余应力后的金属焊接接头结构变化的物理过程。     

还原方法对粉末冶金钼性能的影响

钼粉的形态取决于是由升华的三氧化物MoO_3还是由二钼酸铵(NH_4)_2Mo_2O_7制得的金属,还取决于还原过程使用的还原剂。由于粉末形态不同,使烧结产品的密度不同,同时影响再结晶溫度、强度和延性。     

ATOMISTIC SIMULATIONS FOR Ni/Al INTERMETALLICS

ＡＴＯＭＩＳＴＩＣＳＩＭＵＬＡＴＩＯＮＳＦＯＲＮｉ／ＡｌＩＮＴＥＲＭＥＴＡＬＬＩＣＳＢＡＳＫＥＳＭ．Ｉ．（ＳａｎｄｉａＮａｔｉｏｎａｌＬａｂｏｒａｔｏｒｉｅｓ，Ｌｉｖｅｒｍｏｒｅ，Ｃａｌｉｆｏｒｍｉａ）Ａｂｓｔｒａｃｔ：ＡｌａｒｇｅｎｕｍｂｅｒｏｆＥ...     

时效硬化铝合金2036的深冲性能

众所周知,时效硬化铝合金是具有高的强度/比重之比的材料,它们有希望取代钢作为汽车车身用薄板材料。用于汽车成形部件的材料,要求有极好的成形性能,以及足够的强度、刚度和抗压痕性能。然而,现在对时效硬化铝合金薄板的成形性能知道得太少。本文研究了时效对2036铝合金薄板深冲性能的影响;用不同状态的时效硬化材料试样,鉴定了深冲性     

STUDY ON THE STABILITY OF T’PHASE IN THE Al-Zn-Cu TERNARY SYSTEM

The phase constitutes and phase compositions in the eight alloys designed with dif-ferent compositions of Al--Zn--Cu system have been determined after the homogenoustreatment and then equilibrium cooling to 20℃ by use of optical microscope, electronprobe microanalysis and X--ray diffraction. It has been found that there existed the T'phase in the seven alloys. Consequently, it was testified that the T' phase was stableat room temperature. At the same time, the phase relationship was not locally rightfor the isothermal section of 20℃ of Al--Zn--Cu system of the ASM published in 1997.     

用人工神经网络方法预测鼓泡塔气含率

A new correlation for the prediction of gas hod up in bubble columns was proposed based on an extensive experimental database set up from the literature published over last 30 years .The updated estimation method relying on artificial neural network,dimensional analysis and phenomenological approaches was used and the model prediction agreed with the experimental data with average relative error less than 10%.     

Significance of Wood Terpenoids in the Resistance of Scots Pine Provenances Against the Old House Borer, Hylotrupes bajulus, and Brown-Rot Fungus, Coniophora puteana

We tested how terpenoid (i.e., monoterpenes and resin acids) composition and concentration in wood affects resistance against wood-borers and decaying fungi. Scots pine (Pinus sylvestris) wood from nine provenances having variable terpenoid profiles was studied against the old house borer, Hylotrupes bajulus, and the decay fungus, Coniophora puteana. Provenances represented a 1200-km N-S transect from Estonia to northern Finland, but they were all cultivated for 7 years in the same nursery field, in central Finland. Mean relative growth rate (MRGR) of small H. hajulus larvae positively correlated with the total monoterpene concentration of wood, and feeding was associated with high proportion of levopimaric+palustric acid in wood. Provenance did not affect the MRGR of small or big larvae, but big larvae consumed more wood and produced more frass on the northern Ylitornio trees than on the southern Rakvere and Ruokolahti trees. Low beta-pinene and total monoterpene concentration and low beta: alpha-pinene ratio in wood were all associated with a high number of eggs. The most northern Muonio provenance was the most favored as an oviposition site, differing significantly from Saaremaa, Tenhola, and Suomussalmi. Wood from Saaremaa, Tenhola, Ruokolahti, and Suomussalmi provenance was most resistant against decay fungus, differing significantly from that of Kinnula provenance. However, decay resistance was not clearly associated with the concentrations of wood terpenoids. These results suggest that monoterpene composition of wood affects resistance against wood-boring Cerambycid beetles, but resistance against wood-decaying fungi is not as clearly associated with wood terpenoids.     

Comparing the Variation of Needle and Wood Terpenoids in Scots Pine Provenances

We determined variation in both the concentration and composition of terpenoids in needles and wood within nine Scots pine (Pinus sylvestris) provenances. Seedlings of different provenances representing a 1200-km N–S transect from Estonia to northern Finland were cultivated in Suonenjoki nursery field, central Finland, for seven years. Growth of seedlings and the number of vertical resin ducts in wood were also determined. -Pinene and 3-carene were the major monoterpenes both in the needles and wood. The total monoterpene concentration was about five times higher in the needles than in the wood. A strong positive correlation was found between proportional quantities of several terpenes of the needles and wood, particularly for 3-carene, sabinene, and terpinolene. The needles contained both labdane-type and tricyclic resin acids, whereas the wood contained only tricyclic ones. The wood had a four times higher tricyclic resin acid concentration than the needles. The highest total monoterpene concentration in the needles and in the wood occurred in the most northern Muonio provenance and in the most southern Saaremaa provenance plants, respectively. The amount of high 3-carene genotype trees decreased among the northern provenances. The wood of the most northern Muonio provenance showed the lowest total resin acid concentration, but provenance did not affect total tricyclic resin acids in the needles. Korpilahti provenance trees from central Finland had the best growth in height. In addition, Korpilahti and Ruokolahti provenance trees showed largest radial growth of stem and smallest number of vertical resin ducts. The results suggest that especially the proportional quantity of 3-carene in the needles could be used in estimating the amount of this compound in the wood and vice versa.