In order to compare the different eco-toxicological effects of lead nitrate and lead acetate on forest tree seed, a biological incubation experiment was conducted to testify the inhibition effects of two lead compounds on rates of seed germination, root and stem elongation, and seedling fresh weight for six plants (Amaorpha fruticosa L., Robinia psedoacacia L., Pinus tabuliformis Carr., Platycladus orientalis L., Koelreuteria paniculata Laxm., Hippophae rhamnoides L.) in soil. The results indicate that the inhibition effects of the two lead compounds on the rates of root elongation of plants were greater than other indices; root elongation can possibly be used as indices to investigate the relationship between lead toxicity and plant response. The response of trees to lead toxicity varied significantly, and the order of tolerance to lead pollution was as follows: Amaorpha fruticosa L. > Platycladus orientalis L. > Koelreuteria paniculata Laxm. > Robinia psedoacacia L. > Pinus tabuliformis Carr. > Hippophae rhamnoides L. Therefore, we suggest that Amaorpha fruticosa L. and Platycladus orientalis L. be used as tolerant plants for soil phytoremediation and Hippophae rhamnoides L. as an indicative plant to diagnose the toxicity of lead pollution on soil quality. Lead nitrate and lead acetate differentially restrain seeds, with seeds being more sensitive to lead nitrate than lead acetate in the soil. Thus, the characteristics of lead compounds should be taken into full consideration to appraise its impact on the environment.

The effects of lead were investigated in forest trees (Sophora japonica and Platycladus orientalis) grown in soil and exposed to Pb(CH3COO)2·3H2O (0, 300, 500, 1,000 mg kg−1) with different levels of water stress (100, 80, 60, 40 % soil relative water content, SRW). The results showed that, in the presence of Pb, the ground diameter, height and dry weight were greater than the control for S. japonica and P. orientalis. The proportions of biomass allocation of S. japonica were root > stem > leaf, and of P. orientalis leaf > stem > root except for 40 % SRW. SOD (superoxide dismutase) and POD (peroxidase) activities in leaves were activated by soil Pb for P. orientalis, while SOD activities increased but POD activities decreased compared with control under Pb stress for S. japonica. Water stress increased SOD and POD activities under different Pb concentrations, also increased MDA (malondialdehyde) content significantly. For S. japonica, the Pb concentration in the root was up to 91.9 mg kg−1, while the Pb concentration in the aboveground part was 37.5 mg kg−1. The Translocation Factor (TF value) increased with the increase of water stress intensity, under the same Pb concentration. For P. orientalis, the Pb accumulation in the roots was significantly higher than that in the aboveground part (TF < 1.0). And the total amount of Pb accumulated in P. orientalis was higher than S. japonica. On the basis of this study, it could be concluded that P. orientalis was more suitable for usage in the mining areas of northwest China to accumulate heavy metals, compared with S. japonica.

为探讨土壤重金属污染酶指示的可行性,通过对加入外源铅的填土进行控水培养,研究填土中脲酶和碱性磷酸酶活性的变化及其与土壤铅含量、土壤含水量和理化性质之间的关系.结果表明,土壤相对含水量为80％、60％时,土壤中的脲酶和碱性磷酸酶活性均增加;脲酶和碱性磷酸酶活性随铅含量增加而呈下降趋势,当铅含量为2000 mg/kg时,2种酶活性分别仅为对照的43.7％、61.9％.通径分析表明:各因子对脲酶活性的直接作用顺序为:速效钾＞有机质＞铅＞全氮＞速效磷＞pH＞水分,对碱性磷酸酶活性的直接作用顺序为:铅＞有机质＞全氮＞水分＞pH＞速效钾＞速效磷.土壤速效钾对脲酶活性的直接影响较大,铅、有机质是影响碱性磷酸酶活性的主要因素.2种酶活性变化是铅、水分和土壤理化性质共同作用的结果,且碱性磷酸酶活性较脲酶活性更易受影响.

Objective of this paper was to study changes in growth and antioxidant enzyme activity of Platycladus orientalis seedlings under drought and Pb stress. A potting experiment was conducted with four soil water regimes (40%, 60%,80%, 100% of soil relative water content) and five Pb concentrations(0, 300, 500, 1 000, 2 000 mg·kg-1). The results showed that drought stress restrained growth and antioxidase activities of P. orientalis seedlings, and the effects were more significant with the drought aggravated. The distribution pattern of biomass changed under drought stress, manifested as root> stem> leaf. Pb promoted the growth of P. orientalis seedlings within 2 000 mg·kg-1. The drought stress imposed with 60%, 80% water regimes to P. orientalis seedlings was alleviated within 2 000 mg·kg-1 Pb. Growth index and antioxidase activities of P. orientalis seedlings under treatments with 1 000 mg·kg-1 Pb and 80% of soil relative water content were higher than control, however growth index under other treatments were lower than control. With the soil relative water content decreasing, MDA concentrations increased continually, but with Pb concentration increasing, MDA concentrations increased first, then decreased, and reached the maxmum at 2 000 mg·kg-1. When Pb concentration was 1 000 mg·kg-1, regardless of the water content, MDA content was significantly lower than control. In summary, the resistances of P. orientalis to drought stress could be strengthened under proper drought and Pb interaction.

Through simulative methods,the influences of water and lead on the soil urease,glucose,phosphatase activity of soil were studied.A certain extent water stress had a remarkably activated effect on soil urease,glucose,phosphatase activity.Glucose was the most sensitive to the change of soil water content.The effect of lead on glucose showed activation at low concentration and inhibition at high concentration,while the inhibiting effects on urease and phosphatase increased with the aggravation of lead.The inhibition rate achieved 56.31%,53.21% and 38.11% respectively when 2000 mg·kg-1lead concentration.There existed generally mutual action between soil water content and lead.Under mild water stress,the joint of water and lead stress had antagonism to urease;while had synergism at low lead concentration and had antagonism when lead concentration was higher than 1000 mg·kg-1 to glucose;and had synergism to phosphatase as lead concentration was 300 mg·kg-1.Light water stress interacting with lead demonstrated synergism to urease,glucose,antagonism to phosphatase.Under sever water stress,net varying amounts(ΔU) was lower than zero only at 2000 mg·kg-1 of lead concentration.The joint stress of water and lead induced the greatest ΔU of soil enzyme were 88.4%,50.7% and 25.5% of control.

This research is aimed at exploring the theory of the changes of antioxidant enzyme system activity and MDA content in one year seedlings of Platycladus orientalis treated by different levels of water(40%,60%,80%,and 100%) and lead(0,300,500,1 000,and 2 000mg·kg-1) and cultivated in pots.The results showed that POD,SOD activities of Platycladus orientalis seedlings increased at first and then decreased under interactive stress,POD,SOD activities of Platycladus orientalis seedlings treated by different levels of water reach maximum in the lead content of 500mg·kg-1,under lead less than 500mg·kg-1,POD,SOD activities of Platycladus orientalis seedlings increased in different water stress conditions,under lead more than 500mg·kg-1,POD,SOD activities of Platycladus orientalis seedlings decreased in different water stress conditions.MDA content of Platycladus orientalis seedlings increased gradually under interactive stress,under lead less than 1000mg·kg-1,MDA content of Platycladus orientalis seedlings showed no obvious change in different water stress conditions,under lead more than 1000mg·kg-1,MDA content of Platycladus orientalis seedlings increased gradually under interactive stress.Platycladus orientalis showed stronger resistance in the interaction stress of drought and lead(500mg·kg-1 lead stress and 60% water stress).

Lead is one of the most frequently encountered heavy metals in polluted environment, and it can induce the inhibitory effects on seed germination and seedling growth. PEG is a non-penetrating inert osmoticum, many investigations found that priming with PEG could increase the germination, chilling and salt tolerance of seedlings. In order to determine whether priming with polyethylene glycol (PEG) could increase the resistance to lead stress, seeds of Amorpha fruticosa were primed by soaking in solutions containing 0, 10, 20, or 30% (w/v) PEG-6000, and half of them were re-dried. The seeds of pretreatment were then germinated on filter paper moistened with solutions containing 0, 300, 500, or 1000 mg/L Pb. Results revealed that lead concentrations ≥500 mg/L delayed mean germination time and decreased germination of A. fruticosa. Lead stress had greater inhibitory effect on root growth than on germination, and root growth was more sensitive than shoot growth to lead stress. Priming with PEG could increase the resistance of A. fruticosa to lead stress. Seeds primed in PEG-6000 but not re-dried showed shorter mean germination time, higher germination, and seedlings growth index, dehydration meant the decrease of PEG priming effect in some instances. Seeds primed in 10% PEG-6000 had the highest germination rates when lead concentrations were ≤500 mg/L, while primed in 20% PEG-6000 had the highest germination when lead concentrations were 1000 mg/ L. Root length, shoot length, and fresh weight of A. fruticosa seedlings were greatest in the 20% PEG-6000 treatment. Lead reduced the fresh weight of A. fruticosa seedlings regardless of the PEG pretreatment.

The objective of this experiment is to study changes in the antioxidant enzyme activity and the osmotic solute concentration in Sophora japonica L.seedlings grown under drought and heavy metal(Pb) stress.The pot study used four soil water contents(40%,60%,80%,100% of soil water holding capacity) and five Pb concentrations(0,300,500,1 000,2 000 mg·kg-1).The results showed that peroxidase(POD) and superoxide dismutase(SOD) activity initially increased and then decreased under the combined effects of drought and Pb stress.The combination of drought and Pb stress had less effect than only drought or Pb stress on POD and SOD activity in S.japonica seedlings.The combination of drought and Pb stress had either synergistic or antagonistic effects depending on the conditions.Malondialdehyde(MDA) concentrations gradually increased under the combination of drought and Pb stress,however the MDA concentrations in the drought plus Pb stress(<2 000 mg·kg-1) treatments were still less than those of S.japonica seedlings grown under drought stress alone.This indicated that the interactive effects of drought and Pb caused more membrane damage to S.japonica seedlings than drought stress alone.Drought stress had little effect on soluble sugar concentrations in S.japonica seedlings;however interaction between drought and Pb stress caused soluble sugar contents to increase and then decrease.The soluble sugar concentration of S.japonica seedlings grown under 500 mg·kg-1 Pb stress and 40% of soil water holding capacity was greater than that of S.japonica seedlings in the control treatment(P<0.01).In contrast,the MDA concentration of S.japonica seedlings grown under 500 mg·kg-1 Pb stress and 40% of soil water holding capacity was not significantly different from that of S.japonica seedlings in the control treatment(P>0.05).Proline concentrations gradually increased over time in the 500 mg·kg-1 Pb stress plus 40% of soil water holding capacity treatment,indicating that the combination of drought and Pb stress had synergistic effects.In summary,S.japonica was resistant to the combined effects of drought(40% of soil water holding capacity) and Pb(300,500 mg·kg-1) stress.

建筑是人与自然的中介,建筑与自然的关系是每一个建筑师的永久命题。但在长期的建筑理论和实践的过程中,我们发现当今建筑界人士始终没有认清"建筑是什么"这个根本问题。建筑设计是一个庞大的学科体系并具有丰富的学科内容,需要我们在做设计的时候运用建筑哲学的思想统筹考虑。建筑的哲学思想是以本体论、认识论和方法论来系统阐释宇宙整体物质能量运动和人类认识实践活动的基本规律、具体方法,并将此延伸应用至人类的建筑认识实践活动中去,从而使哲学思想在现在建筑中得到充分的运用。建筑设计作为协调人与自然关系的具体实践活动,其必然要遵循哲学思想。系统观、辩证观和科技观组成了哲学理论体系。

In concrete structure,the concrete powder interface directly determine the binding properties of concrete to build the compression,tensile,shear,such as performance,using advanced technology by means of concrete powder interface node performance testing is to determine the key components of concrete.This article discusses the GEM,XRD,EPMA,EDS,HYMOSTRUC detection technology and other equipment on the concrete powder testing the role of the interface node.

Tungsten carbide (WC) powder has been widely studied because of its catalytic properties in some organic reactions. Nanocrystalline tungsten carbide powders with large surface area can provide a large number of catalytic active centers (situ) to reactions. In this article, a new process of preparing Nanocrystalline tungsten carbide powder by embedment-direct reduction and carburization was studied. The nanocrystalline WC powder with average 40 nm grain size was synthesized by embedment-direct reduction and carburization at 1300°C and 3 hours' heat preservation.

While the Co3O4, transition-metal oxides (V2O5, Ta2O5, MoO3 and TiO2) and carbon black was the raw materials, ultrafine Co-inhibitor composite powders (Co-VC, Co-TaC, CO-Mo2C and Co-TiC), which can be applied in hardmetal industry, were synthesized via direct reduction & carbonization process in vacuum. Phases of the resultants synthesized at different temperatures and in different dwell time were detected by XRD. The morphology of the composite powders was observed by SEM. Results show that ultrafine Co-inhibitor composite powders could be synthesized at low temperatures, which were effectively reduced by the participation Of Co3O4. The mechanism of low-temperature carbonization was studied by comparative experiments and thermodynamic analysis.

Al2O3-ZrO2-YAG powder was prepared by low temperature in situ synthesis method.The results showed that the main phase in Al-Zr-Y-O system at 1100℃ is tetragonal zirconia,while the others are amorphous phases.This indicates that the crystalline growth of Al2O3 and YAG are restrained by ZrO2,and the transformation of ZrO2 from a tetragonal phase to a monoclinic one is inhibited by Al2O3 and YAG.The phase composite in Al-Zr-Y-O system at 1580℃ is (115+90x)Al2O3+54(Y2O3)x·ZrO2+(32-36x)YAG,while 0 ≤x0.88(mol).

WC-10Co nanocomposite powders were produced by continuous spray pyrolysis & carbonization technology and Ti-coated cubic boron nitride(CBN)was prepared by using chemical vapor deposition.Hot-pressing sintering technology was used to prepare CBN-WC-10Co composites at 1380℃under 30 MPa for 60 minutes.The microstructure,density,transverse rupture strength(TRS),and bonding conditions between CBN and ultrafine WC-10Co matrix were studied.The average grain size of WC grains is 400 nm,TRS of CBN-WC-10Co composites is more than 750 MPa and the relative density is 94.2%.CBN-WC-10Co composites with homogeneous microstructure and good mechanical properties are obtained.