不同土壤水分条件对长白山阔叶红松林5种树种的生理生态特性的影响(英文)

水分亏缺影响植物的整个生长过程,不论是外部形态还是内部结构以及各种代谢过程均受到影响。不同植物对其不同程度水分亏缺的响应是不同的,这主要是由于不同植物在不同水分条件下碳同化与水分利用机制间存在差异的结果。本研究以组成长白山阔叶红松林主要树种红松、水曲柳、胡桃楸、椴树和蒙古柞的幼苗为研究对象,盆栽于模拟干旱条件下,其土壤含水量分别为田间持水量(37.2%)的85%~100%(CK)、65%~85%、(MW)和45%~65%(LW)。讨论了不同模拟干旱强度对树木耐旱特征、净光合速率、蒸腾速率和水分利用率等参数的影响。结果表明,所有供试树种经模拟干旱处理后叶片耐旱特征增加:叶片厚度、自由水含量和肉质度增加,比叶面积减小。不同树种的光合速率对不同土壤水分条件反映趋势基本相似,除水曲柳在轻度土壤水分亏缺下光合速率和水分利用率比对照组有所提高外,其它4个树种光合速率和水分利用率均下降,但蒸腾速率对土壤水分含量反应不一,反映出幼树对对土壤水分含量适应的复杂性。表3参15。

细辛精油对5种木本花卉病害的离体抑菌效果比较

采用生长速率法和孢子萌发法测定了细辛精油对引起木本花卉叶部病害的5种病原菌(牡丹炭疽病、牡丹拟盘多毛孢叶斑病、月季黑斑病、肉桂链格孢叶斑病和龙血树镰孢叶斑病)的菌丝生长和孢子萌发的抑制作用。结果表明:细辛精油对牡丹拟盘多毛孢叶斑病菌菌丝生长和孢子萌发的抑制效果均为最好,EC50分别为120.43 mg/L和110.66 mg/L;对于同一种病原菌来说,细辛精油对牡丹炭疽病菌和肉桂链格孢叶斑病菌菌丝生长的抑制作用强于对其孢子萌发的抑制作用,对牡丹拟盘多毛孢叶斑病菌和龙血树镰孢叶斑病菌孢子萌发的抑制作用强于对其菌丝生长的抑制作用。

多晶富镉Hg_(1-x)Cd_xTe的电沉积及Hg_(0.09)Cd_(0.91)Te薄膜的光电化学行为

本文研究了在酸性CdSO_4+HTeO_2~+6HgCl_2 电解液中多晶富镉Hg_(1-x),Cd_(?),Te(x>0.5)的电沉积过程,实现了三种离子在同一电位下共沉积的技术。对在钛基底上沉积出的薄膜进行XRD,SEM和EDAX分析,结果表明薄膜为闪锌矿型的多晶结构,分布均匀连续。考察了(1—x)=0.09时多晶薄膜在多硫氧化还原电对液中的光电化学行为,光强为100mW/cm~2时,短路光电流I_(sc)=1.88mA/cm~2,开路光电压V_(oc)=0.25V,填充因子F·F=0.22。由光电化学光谱所确定出的禁带宽度E_g=1.26eV,Mott-schottky曲线给出了电极的平带电位φfb为—1.26V(vs.SCE),从而得到开路光电压V_(oc)可能达到的最大值为0.49V。因此,多晶富镉Hg_(1-x)Cd_xTe薄膜是一种很有潜力的光活性电极材料。

牦牛放牧率和放牧季节对小嵩草高寒草甸土壤养分的影响

经过两年牦牛放牧试验表明,夏季草场不同土壤层有机质、有机碳、全磷、全氮和速效磷的含量及0～20cm土壤层营养因子的平均含量与放牧率呈线性回归关系,速效氮含量与放牧率呈二次回归关系;冬季草场不同土壤层有机质、有机碳和全氮与放牧率呈线性回归关系,全磷、速效磷和速效氮的含量及0～20cm土壤层营养因子的平均含量与放牧率呈二次回归关系。随着放牧率的逐渐增加,夏季草场不同土壤深度速效氮含量也逐渐减小,当放牧率达到1.07、1.08和1.22头·hm-2时,0～5、5～10、10～20cm土壤速效氮含量依此达到最小;冬季草场不同土壤层全磷、速效磷和速效氮含量逐渐增加,当放牧率达到0.81、0.78和1.00头·hm-2,1.03、1.09和1.03头·hm-2,1.36、1.35和1.30头·hm-2时,0～5、5～10、10～20cm土壤层全磷、速效磷和速效氮含量分别依此达到最大。在夏季草场,0～20cm土壤层速效氮平均含量达到最小放牧率是1.07头·hm-2;冬季草场0～20cm土壤层全磷、速效磷和速效氮含量达到最大放牧率分别是0.90、0.83和1.21头·hm-2。

In situ preparation of Ir/ZSM-5/cordierite honeycombs and their application for NOx abatement

ZSM-5 zeolites were synthesized in situ onto cordierite honeycombs by vapor phase transport (VPT) for the first time. The as-synthesized ZSM-5/cordierite honeycombs were impregnated with IrCl3 and tested for NOx reduction with a simulated exhaust gas as the reducing agent. Under the conditions of excess oxygen, the Ir/ZSM-S/cordierite monolith catalyst exhibited NO reduction of 73% at a temperature of 573 K and a space velocity of 20,000 h(-1).

3-5岁幼儿认知灵活性的发展

To test preschoolers’ development of cognitive flexibility--an ability to solve a problem in one way and to then switch solution strategies, and the mechanism involved in the development, 3-5-year-olds are asked to perform switching tasks in which the experimenter manipulates the way the stimuli are presented: consecutive or simultaneous; the way the switching happens: between dimensions or within a dimension; the conceptual domains involved: shape, color, number and direction; the specific labels used. The main results of this work are presented below: (1) 3-5-year-olds’ cognitive flexibility develops with age, yet its development is not of the same speed in extra-dimensional switch tasks and inter-dimensional reversal tasks. 3-year-olds manifest some cognitive flexibility, but their performance is significantly worse than that of 4- and 5-year-olds. For the 3-year-olds, in reversal tasks, although 80% of the children passed the post-switch phrase in color task; less then 60% children passed the post-switch phrase in shape, number and direction tasks. In extra-dimensional tasks, 3-year-olds performance is worse than that in the reversal tasks. Less than 50% of the children passed the tasks. Children’s cognitive flexibility develops fast from 3-year-olds to 4-year-olds. Both 4-year-olds and 5-year-olds demonstrate high flexibility without significant difference between them. (2) Children’s flexibility in the conceptual domains of shape, color, number and direction follows different developing patterns. In inter-dimensional reversal tasks, 3-year-olds’ performance is not the same in the 4 conceptual domains, but the difference among the domains is insignificant in 4-and-5-year-olds. In extra-dimensional switching tasks, children’s performance on the 4 domain tasks is significantly different from one another in 3-, 4-, and 5-year-olds. (3) The way the stimuli are presented affects children’s development of cognitive flexibility. In inter-dimensional reversal tasks, 3-year-olds’ performance in consecutive presentation is significantly better than that in simultaneous presentation. 4- and 5-year-olds’ performance in the 2 presentations is not significantly different from each other. In extra-dimensional switch tasks, 3-, 4-, and 5-year-olds’ performance in the consecutive presentation is not significantly better than that in the simultaneous presentation (4) 3-, 4-, and 5-year-olds’ self-issued labeling aids their performance on the switching tasks. Children’ performance in the labeling condition is significantly better than that of no labeling. (5) 3-5-year-olds’ cognitive flexibility is highly correlated with their working memory and inhibition. Children’ development of cognitive flexibility is a process that involves activation of working memory and inhibition, in which the complexity of the task also plays a role.

Effect of variations in acid properties of HZSM-5 on the coking behavior and reaction stability in butene aromatization

In order to investigate the effect of acid properties on the coke behavior and stability of butene aromatization, we prepared the AHZSM-5 samples with various acid properties by the methods of hydrothernial treatment and K addition. The reaction of butene aromatization was carried out at 350 degrees C and 0.5 MPa in a continuous flow fixed bed. The characterization of the fresh/coked catalysts with NH3-TPD, N-2 adsorption-desorption measurement, and TG techniques has shown that a large amount of acid sites (high acid density) of the AHZMS-5 catalyst can cause a large quantity of coke deposit and serious channel blockage, and so result in a rapid loss of aromatization activity. On the contrary, after a great reduction in strong acid sites of AHZSM-5 catalyst resulting from some K-modification, the presence of only many weak acid sites also could not lessen the formation of coke nor improve the reaction stability of butene aromatization. Interestingly, the simultaneous reduction in the strong and weak acid sites to a desirable level by hydrothermal treating the AHZSM-5 catalyst at a proper temperature can effectively suppress the coke formation and channel blockage, and thus improve its olefin aromatization stability. (c) 2005 Elsevier B.V. All rights reserved.