PdNPs/MWNTs修饰玻碳电极的制备及其对六价铬的电化学测定

用钯纳米粒子多壁碳纳米管修饰玻碳电极,并用于对六价铬(Cr(VI))的电化学测定.采用场发射扫描电子显微镜、循环伏安法、交流阻抗法、差分脉冲伏安法等方法对修饰电极进行了表征.研究发现多种其他金属离子如Cr3+、Pd2+、Zn2+、Pb2+、Cu2+、Al3+、Ba2+、Ca2+、Mg2+等对六价铬离子的测定没有明显干扰,且六价铬的还原峰电流与Cr(VI)的浓度在8×10-7~5×10-8mol/L范围内呈良好线性关系,检测限达2.7×10-8mol/L.该法具有简便快速,选择性好,灵敏度高等特点.     

聚苏木精/氧化石墨烯修饰玻碳电极测定水样中痕量铅和镉

将玻碳电极用氧化石墨烯修饰后电聚合上苏木精聚合膜,利用该修饰电极差分脉冲溶出伏安法同时测定铅和镉.对支持电解质及其缓冲溶液、富集电位及富集时间测定条件进行了优化.在0.1 mol/L pH 3.5的NaAc-HAc缓冲液中,以此修饰电极为工作电极,在-1.1 V处搅拌富集220 s,用差分脉冲伏安法分别测定-0.58 V和-0.8V处的氧化峰电流.结果表明,该电极显著提高了铅和镉的电化学响应信号.在优化条件下,峰电流与铅和镉的浓度在0.01~1μmol/L范围内呈良好的线性关系,相关系数为0.991~0.995.检出限分别为8 nmol/L(Pb2+)和1 nmol/L(Cd2+)(S/N=3).将该法用于实际水样中痕量铅和镉的测定,回收率为92.2%~105.8%.     

聚苯胺/氯化银复合材料修饰电极测定铅(Ⅱ)

制备了聚苯胺/氯化银修饰的玻碳电极(PANI/Ag Cl/GCE),并用于检测铅离子。结果表明:铅离子在修饰电极上具有良好的电化学响应,用差分脉冲溶出伏安法可对Pb2+进行灵敏检测。研究了p H值、沉积电位和时间等因素对铅离子响应信号的影响。在最佳测定条件下,在0.5~70 nmol/L范围内,铅离子浓度与电化学信号呈线性变化关系,检出限为0.1 nmol/L,回收率在97.9%~100.7%之间,RSD为2.7%~5.4%。本方法简捷、快速灵敏,适于痕量铅含量测定。     

谷胱甘肽自组装膜修饰电极用于Cr(VI)离子的测定

将谷胱甘肽(GSH)自组装膜修饰电极用于Cr(Ⅵ)的测定.实验表明,在0 02mol/LH2SO4 0 1mol/LNaNO3溶液中,在 1 00～-0 40V电位范围内进行循环伏安扫描,于 0 29V(Vs.SCE)处获得铬的还原峰信号、 0 65V(Vs,SCE)处获得铬的氧化峰信号.Cr(VI)在GSH/Au修饰电极上的电化学行为比裸金电极有明显的改善,峰电流更为灵敏,且还原峰电流随着Cr(VI)浓度的增加而增大,因此选择 0 29V的还原峰作为分析信号,运用1 5次微分线性扫描伏安法对铬进行了定量分析,线性范围为1 0×10-8～1 0×10-6mol/L,检测限为1 0×10-9mol/L.将所建立的方法应用于湖水样品中铬含量的测定,以ICP进行对照实验,结果满意.     

漆酚金属盐聚合物修饰电极伏安法测定水样中痕量铜的研究

用漆酚金属盐聚合物修饰碳糊电极能高灵敏度测定水样中痕量的Cu~(2+)。在pH6.0的HAc+NaAc缓冲溶液中,在电极表面Cu~(2+)通过化学和物理吸附而富集,在溶出过程中,于-0.04V(vs.SCE)处有一灵敏的氧化峰。该修饰电极测定Cu~(2+)的线性范围为4×10~(-9)～2.5×10~(-7) mol/L,富集20min后检测限为8×10~(-11)mol/L。用该修饰电极测定了环境水样中的铜离子,平均回收率为99.10％。     

碳纳米管和离子液体修饰电极对鸟嘌呤的电催化性能研究

以多壁碳纳米管(MWNTs)和疏水性离子液体1-丁基-3-甲基咪唑六氟磷酸盐(BMIMPF6)按一定比例制备成胶体,修饰在电极表面制备成MWNTs-BMIMPF6/GCE修饰电极,以铁氰化钾为电化学探针,用循环伏安法和交流阻抗法对修饰电极进行表征,考察鸟嘌呤在修饰电极上的电催化行为。结果表明,该修饰电极显著的增强了对鸟嘌呤的电催化性能,氧化峰电位负移,峰电流提高约7～8倍;以差分脉冲伏安法对溶液中的鸟嘌呤进行测定,其检测线性范围为1.5×10-6～2×10-4mol/L,检出限为2×10-7mol/L。     

钯纳米粒子修饰的玻碳电极对Cu~(2+)的电化学检测

文章用一步法合成N-N-二甲基甲酰胺(DMF)保护的钯纳米粒子(DMF-Pd NPs),通过紫外可见光谱、透射电镜(TEM)和循环伏安法对钯纳米粒子及其修饰的玻碳电极进行了表征,并将此电极用于铜离子(Cu~(2+))的电化学检测。结果表明:氧化峰电流与Cu~(2+)浓度在4×10-7~5×10-4 mol/L范围内呈良好的线性关系,相关系数为0.999 0,检出限(S/N=3)为5×10-8 mol/L。该方法具有简便、选择性好,对于环境水样中Cu~(2+)的检测具有潜在的应用价值。     

聚结晶紫膜传感器测定槲皮素

利用电化学聚合法制备聚结晶紫膜修饰玻碳电极传感器.在磷酸盐缓冲溶液中,采用循环伏安法和差分脉冲伏安法研究槲皮素在该修饰电极上的电化学行为.结果表明,此修饰电极对槲皮素氧化和还原能力具有明显的增强作用.实验条件经优化后,槲皮素在聚结晶紫膜修饰电极上的氧化峰电流与其浓度在5.0×10~(-6)~1.5×10~(-4)mol/L范围内呈良好线性关系,相关系数为0.997,检出限为8.0×10~(-7)mol/L.用于芦丁水解产物中槲皮素的测定,回收率为102.8%~104.3%,RSD2.5%.     

PEI/SiO_2纳米粒子自组装修饰电极及六价铬离子的电化学发光分析方法研究

利用反相微乳液方法合成了PEI/SiO2复合纳米粒子,通过透射电子显微镜(TEM)、Zeta电位对该复合纳米粒子进行了表征。该复合纳米粒子可以基于超分子作用自组装于Nafion/CNT修饰电极表面,并基于该修饰电极对铬酸根(CrO2-4)的富集效应及CrO2-4的电还原产物Cr(Ⅲ)对鲁米诺-H2O2化学发光体系强烈的催化作用,建立了一种高选择性的测定六价铬离子Cr(Ⅵ)的电化学发光新方法。     

木犀草素在钯-石墨烯复合材料修饰电极上的电化学测定

用正己基吡啶六氟磷酸盐作为粘合剂制备了离子液体修饰碳糊电极(CILE),将钯-石墨烯(Pd-GR)复合材料修饰于CILE表面制得修饰电极(Pd-GR/CILE),并利用循环伏安法和示差脉冲伏安法(DPV)对木犀草素在该修饰电极上的电化学行为进行研究.结果表明在pH 1.5的磷酸盐缓冲溶液中木犀草素在该电极上循环伏安扫描得一对峰形良好的氧化还原峰,说明木犀草素的电化学反应得以实现.在优化条件下木犀草素的氧化峰电流与其浓度在1.0×10~(-9)~1.0×10~(-6)mol/L内存在线性关系,检测限为3.3×10~(-10)mol/L(3σ).利用本方法测定独一味胶囊中木犀草素的含量,回收率在95.6%~104.8%范围内,相对标准偏差(RSD)低于3.43%.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.