川西平原岷江流域冲积性水稻土中Be和V的背景值研究

本文在文献［１］和［２］的基础上，首次对川西平原岷江流域冲积性水稻土中Ｂｅ和Ｖ的背景值进行了研究，并对Ｂｅ和Ｖ在不同土层的分布情况亦进行了一定的研究     

德化县景观格局及空间差异性分析

景观格局是景观生态学的基本研究内容,数量化分析景观组分的空间分布特征,是进一步研究景观功能和动态的基础,它可为景观的合理管理提供有价值的资料.本课题以福建省德化县作为研究区域,使用G1S技术和景观格局分析软件FRAGSTATS,分析了德化地区的景观格局和空间差异性,并从物种多样性保护角度出发,对当前地类分布的优势和不足进行了分析,并提出了改进措施.     

Role of Ppt1 in multiple stress responses in Candida albicans

To study the function of CaPptl, we deleted PPT1 gene from the Candida albicans genome by sequentially replacing the entire coding region with the selectable markers ARG4 and HIS1. The results showed that the deletion of Pptl did not affect the hyphal formation of C. albicans under serum induction and caused enhanced sensitivity to DNA damage, Calcofluor white and salt- induced stress. We also found that Pptl was not required for the phenotypic response of cells treated with the genotoxins, methylmethane sulfonate and hydroxyurea. Flow cytometric analyses indicated that pptlA cells and wild-type cells showed similar G2/M arrest profiles when exposed to DNA damage stress. Pptl was not required for the activation of the DNA damage response pathway, as indicated by normal phosphorylation of Rad53 and Rfa2 in pptlA cells under DNA damage stress. We suggest that Pptl plays important roles in response to various stress conditions in C. albicans.     

异丙烯膦酸的合成及表征

本文以三氯化磷（ＰＴ），丙酮（ＡＬ）和冰醋酸（ＡＡ）为原料合成了异丙烯膦酸（ＩＰＰＡ），详细探讨了原料配比、反应温度和反应时间对产物收率的影响，并用红外光谱、３１ＰＮＭＲ、１ＨＮＭＲ和１３ＣＮＭＲ证实了产物的结构。     

Study on the viscoelastic behavior of SEEPS block copolymer based on a modified BSW model

Studies on the viscoelastic behavior of styrene[ethylene-（ethylene-propylene）] -styrene block copolymer （SEEPS） were carried out, and some characteristic viscoelastic parameters were calculated. The longest relaxation time was obtained through simulating the relaxation spectrum on the basis of a modified Baumgaertel-SchausbergerWinter （mBSW） model. The results revealed that there exists a “second plateau” in the low frequency region of the master curves. The reason for this phenomenon is attributed to the entanglement of macromolecular chains. It is suggested that the hard blocks, polystyrene, act as entanglement points, resulting in a topology restraint to the movement of macromolecular chains. Meanwhile, it is found that the horizontal shift factors （aT） vs temperature in the master curve could be fitted to the WiUiams-Landel-Ferry （WLF） equation and Arrhenius equation respectively and the flow activation energy （Ea） is 127.88 kJ/mol. In addition, the plateau modulus （GN） and entanglement molecule weight （Me） were calculated.     

N_2O—C_2H_2火焰原子吸收法测定土壤中痕量铍和钒

本文在文献［１］、［２］的基础上，进一步研究了用Ｎ＿２Ｏ—Ｃ＿２Ｈ＿２火焰原子吸收法测定土壤样品中痕量Ｂｅ和Ｖ时，样品的消解方法及消除共存组分干扰的方法，从而建立了Ｎ＿２Ｏ—Ｃ＿２Ｈ＿２火焰原子吸收法测定土壤样品中痕量Ｂｅ和Ｖ的方法。该法具有抗干扰能力强、准确可靠、简便易行、线性范围较宽的特点。测定Ｂｅ的线性范围为０—１μｇＢｅ／ｍＬ试液；测定Ｖ的线性范围为０—２５μｇＶ／ｍＬ试液。测定Ｂｅ和Ｖ的灵敏度（１％吸收）分别为０．０１４μｇ／ｍＬ和０．５１μｇ／ｍＬ，检测限分别为０．００７μｇ／ｍＬ和０．２５μｇ／ｍＬ。     

N_2O－C_2H_2火焰原子吸收法（FAAS）测定土壤中痕量钒—有关干扰作用

本文采用一种新的思路，较详尽地研究了用Ｎ＿２Ｏ－Ｃ＿２Ｈ＿２ＦＡＡＳ法测定土壤中痕量钒时，共存组合对Ｖ的干扰作用，并在此基础上探讨了主要干扰组合对Ｖ的原子吸收信号产生干扰的作用机理。为消除干扰提供了依据，同时，为研究土壤中Ｖ的背景奠定了必要的基础。     

北魏以来的浑善达克沙地和科尔沁沙地

通过史料考证，提出以下观点：1）北魏时浑善达克、科尔沁两个地区已有沙漠存在，当时称石漠、松漠或大漠；2）辽初至辽末科尔沁沙地沙化程度及分布情况与现代相似；3）元代浑善达克沙地之南北宽度及景观与现代相同；4）20世纪50年代以来沙漠化正过程的主因是草原过度放牧；5）治沙的最佳选项是建设人工草场及围封天然草场，退牧还草．     

丙烯酰胺－丙烯酸共聚合反应的研究

本文采用氧化还原引发体系，以丙烯酰胺（ＡＭ）和丙烯酸（ＡＡ）为单体进行水溶液自由基共聚合。研究了引发剂用量，温度，时间，ｐＨ值，单体配比等对共聚合反应的影响，并考察了共聚物的红外光谱特征。     

GdFeCo磁光薄膜飞秒激光感应反常磁滞回线研究*

该文使用飞秒时间分辨泵浦-探测磁光克尔光谱技术,研究了飞秒激光加热GdFeCo磁光薄膜跨越铁磁补偿温度时,净磁矩方向发生转变而引起磁化反转的反常克尔磁滞回线。通过测量不同激发功率下以及不同泵浦脉冲数下的反常克尔回线,揭示反常回线包含连续脉冲激发产生的积累效应以及外场磁化史的记忆效应,对反常回线的形成起源做了深入探索和详细研究。研究结果对于深入理解GdFeCo合金薄膜中稀土-过渡金属间的反铁磁耦合特性以及磁化反转的机理具有重要意义。