镧对镉胁迫下豌豆幼苗根部细胞内离子平衡及膜质子泵的影响

以水培豌豆(PisumsativumL)幼苗为材料,研究了La3+对Cd2+胁迫下豌豆幼苗生长、叶部与根部细胞对Cd2+的吸收、根部细胞内无机离子平衡体系及膜H+-ATPase,H+-PPase活性的影响。结果表明:Cd2+胁迫下喷施适宜浓度的La3+(0.50mg·L-1)可使豌豆幼苗相对生物量、苗长、叶绿素含量以及光合速率受到的毒害明显缓解,有效减少叶部与根部细胞对Cd2+的吸收,显著减轻了Cd2+胁迫导致的离子平衡系统的紊乱,明显缓解Cd2+对质膜及液泡膜H+-ATPase,H+-PPase活性的抑制作用。10mg·L-1Cd2+胁迫下La3+的保护效应比30mg·L-1Cd2+胁迫下更为显著。样品中La3+的测定和分析结果还表明,外源La3+处理后,La3+主要结合于细胞膜外,进入原生质体的仅占很小部分,但30mg·L-1Cd2+处理样品中La3+进入细胞的量则明显多于10mg·L-1Cd2+处理的样品。     

Fabrication of ultrathin films with large third-order nonlinear optical properties.

An ultrathin composite film containing anionic Ag-His complexes (His: L-Histidine) and oppositely charged BH-PPV was fabricated by means of the electrostatic layer-by-layer self-assembly technique. UV/Vis spectra showed a continuous deposition process of Ag-His complexes and BH-PPV. The film structure was characterized by using small-angle X-ray diffraction, AFM, and SEM. The nonlinear optical properties of the ultrathin film were studied by using the Z-scan technique with a laser duration of 8 ns at a wavelength of 532 nm. The film sample exhibited a strong nonlinear saturated absorption, with an alpha2 value of -3.9 x 10(-5) mW(-1) and a self-defocusing effect with an n2 value of -4.78 x 10 (-12) m2W(-1).     

Synthesis of isoxazoline-fused chlorins and bacteriochlorins by 1,3-dipolar cycloaddition reaction of porphyrin with nitrile oxide

The 1,3-dipolar cycloaddition reaction of meso-tetraaryl porphyrin with 2,6-dichlorobenzonitrile oxide yielded novel isoxazoline-fused chlorins and two stereoisometric bacteriochlorins. The crystal structure of bacteriochlorin was characterized by X-ray diffraction.     

Molar conductivity calculation of Li-ion battery electrolyte based on mode coupling theory

A method is proposed to calculate molar conductivity based on mode coupling theory in which the ion transference number is introduced into the theory. The molar conductivities of LiPF6, LiClO4, LiBF4, LiAsF6 in PC (propylene carbonate) are calculated based on this method. The results fit well to the literature data. This presents a potential way to calculate the conductivities of Li-ion battery electrolytes.     

Characterization and complementation of a Pichia stipitis mutant unable to grow on d-xylose or l-arabinose

Pichia stipitis CBS 6054 will grow on d-xylose, d-arabinose, and l-arabinose. d-Xylose and l-arabinose are abundant in seed hulls of maize, and their utilization is important in processing grain residues. To elucidate the degradation pathway for l-arabinose, we obtained a mutant, FPL-MY30, that was unable to grow on d-xylose and l-arabinose but that could grow on d-arabinitol. Activity assays of oxidoreductase and pentulokinase enzymes involved in d-xylose, d-arabinose, and l-arabinose pathways indicated that FPL-MY30 is deficient in d-xylitol dehydrogenase (D-XDH), d- and l-arabinitol dehydrogenases, and d-ribitol dehydrogenase. Transforming FPL-MY30 with a gene for xylitol dehydrogenase (PsXYL2), which was cloned from CBS 6054 (Gen Bank AF127801), restored the D-XDH activity and the capacity for FPL-MY30 to grow on l-arabinose. This suggested that FPL-MY30 is critically deficient in XYL2 and that the d-xylose and l-arabinose metabolic pathways have xylitolas a common intermediate. The capacity for FPL-MY30 to grow on d-arabinitol could proceed through d-ribulose.     

2,8,9-三氧杂-5-氮杂-1-硼杂双环[3,3,3]十一碳烷的合成

本文报导了具有N→B配位键的2,8,9-三氧杂-5-氮杂-1-硼杂双环[3,3,3]十一碳烷的合成及性质。化合物(1)的制备已有报导,而化合物(2),(3)则为新的化合物。我们研究了它们的成环条件,制备的最佳条件及化学稳定性。     

镍氢动力电池用AB5型贮氢合金热处理工艺的研究

本文对镍氢动力电池用AB5型纳米晶贮氢合金热处理工艺进行了研究.分别采用X射线衍射、金相、PCI测试手段分析热处理后贮氢合金的微观结构与吸放氢动力学性能.贮氢合金的电性能测试结果表明,经过950℃×6 h热处理的贮氢合金,10C放电比容量可以达到241mAh/g,循环寿命大于500次,分别以7C,10C放电,高倍率放电率(HRD)为92.5%,85.2%.将贮氢合金粉组装成电池进行测试,2min后,放电平台电压为1.143V,以10C放电,300次循环后,电池容量衰减率较小.     

分数导数结合傅里叶最小二乘拟合处理含噪音的重迭信号

提出了一种含噪音重迭信号的综合处理方法 :先用傅里叶最小二乘法拟合噪音数据 ,然后对拟合后的信号求 2 .5次导数 ,在对模拟数据研究的基础上 ,讨论了求导后峰位漂移及其影响因素 ,给出了一个用于矫正峰位值的经验公式。用该方法对模拟和实际的紫外含噪音重迭信号进行处理 ,结果良好     

A new type of two-dimensional packed + capillary column GC system. I. Theory

Summary To match the need of high efficiency capillary column (plate number N₂, Plate height H₂ and carrier gas linear velocity U₂), a new high efficiency packed column (N₁, H₁ and U₁) at high carrier gas velocity with small capacity factor has been developed in the light of theoretical discussion of factors effecting the column efficiency utilization ratio.