自组装纳米Au电极及其对H2O2催化氧化的研究

 研究了纳米粒子-金溶胶在铂金电极表面的单分子层自组装,并探讨了K₃Fe(CN)₆在金溶胶表面的电化学吸附性质;同时,以金溶胶修饰电极为工作电极,铂金电极为对电极,Ag/AgCl电极为参比电极组成的三电极系统对H₂O₂有良好的催化氧化作用,在1.0×10^-6～1.0×10^-3mol/L的浓度范围内与氧化峰峰电流呈良好的线性关系,为纳米自组装修饰电极在电化学及生物催化反应等方面的应用开辟了新的途径.     

金属离子对钢在没食子酸/硫酸介质中的腐蚀行为研究

 用失重法研究了4种金属离子(Na⁺,Zn²⁺,Cu²⁺,Fe³⁺)在0.5 mol/L H₂SO₄以及500 mg/L没食子酸+0.5 mol/L H₂SO₄介质中在20℃对冷轧钢腐蚀行为的影响.结果表明:Cu²⁺对钢的腐蚀起抑制作用;而其余3种金属离子(Na⁺,Zn²⁺,Fe³⁺)对钢的腐蚀起加速作用.在相同条件下,冷轧钢在0.5 mol/L H₂SO₄溶液中的腐蚀速率顺序为:Cu²⁺2++3+;而在500 mg/L没食子酸+0.5 mol/L H₂SO₄介质中,腐蚀速率顺序为:Cu²⁺2+3++.     

聚谷氨酸修饰碳糊电极的制备及其对铜离子的测定

 制备了聚谷氨酸修饰碳糊电极,通过循环伏安法和交流阻抗法研究了K₄Fe(CN)₆/K₃Fe(CN)₆在修饰电极上的电化学行为,结果显示碳糊电极修饰聚谷氨酸后,K₄Fe(CN)₆/K₃Fe(CN)₆的氧化还原峰电流变大、交流阻抗变小.采用阳极溶出伏安法将所修饰碳糊电极用于铜离子的检测,在pH=4.50的醋酸-醋酸钠缓冲液中,于-0.20 V 电位下将Cu²⁺还原富集后再进行阳极氧化扫描,在0.14 V处获得一灵敏的铜的溶出峰,峰电流与铜浓度在1.57×10^-8~1.57×10^-5 mol/L的范围内呈良好的线性关系,最低检测限为5.00×10^-9 mol/L.制备的聚谷氨酸修饰碳糊电极成功用于铜离子的测定.     

4A和13X分子筛去除水中重金属Cd2+及其吸附性能研究

以4A和13X分子筛为吸附材料,考察废水pH值和Cd²⁺初始浓度等对Cd²⁺去除率的影响,并研究了分子筛对Cd²⁺的吸附性能。结果表明,4A和13X分子筛投加量为0.16g/L、废水pH值为5、Cd²⁺浓度为20mg/L时,Cd²⁺去除率达到95%以上;分子筛对Cd²⁺的去除机理以离子交换吸附为主,交换出来的Na⁺与分子筛吸附的Cd²⁺摩尔浓度比为2;在吸附热力学和动力学方面,4A和13X分子筛均符合Langmuir吸附等温模型和Lagergren二级速率方程,计算的饱和吸附容量Q₀分别为150.15、163.67mg/g,二级反应速率常数K₂分别为2.45×10-3、3.96×10-4 g/(mg·s)。该吸附反应是一种单分子层反应速度较快的化学吸附过程。     

BLim1/2+(m=6、7)团簇的结构及储氢性能的研究

为开发新型储氢材料提供更为丰富的理论基础,采用B3LYP泛函在6-311++G(d,p)基组水平上对BLi₆⁺超碱团簇和BLi₇²⁺超碱土团簇的稳定性结构、电荷分布等方面进行理论研究,进而研究团簇的储氢性能。结果表明：两个离子团簇均比它们所对应的中性团簇均具有较高的动力学稳定性。两个离子团簇中的每个Li原子同时有效吸附2个氢分子,BLi₆⁺团簇中氢分子在团簇表面平均吸附能为0.969~2.162kCal/mol,储氢质量分数达31.56wt%。而BLi₇⁺团簇中氢分子在团簇表面平均吸附能为1.764~3.714kCal/mol,储氢质量分数达32.21wt%。它们的储氢性能表明BLi₆⁺团簇和BLi₇²⁺团簇均有望成为良好的储氢媒介。     

CdS/Ru（bpy）32+电致化学发光传感器的构建及邻苯二酚的检测

基于硫化镉量子点（CdS QDs）对三联吡啶钌（Ru（bpy）₃²⁺）电致化学发光（ECL）信号的增敏作用,在电极表面滴涂CdS QDs,然后引入含有多壁碳纳米管（MWCNTs）和金纳米粒子（Au NPs）的（Ru（bpy）₃²⁺）复合物（MWCNTs-Au NPs-Ru（bpy）₃²⁺）,得到了自增强CdS/Ru（bpy）₃²⁺ECL传感器.该传感器同时包含了ECL物质Ru（bpy）₃²⁺和共反应剂CdS QDs,具有自增强特点,MWCNTs和Au NPs的存在可进一步放大传感器的信号.邻苯二酚的电极氧化产物与Ru（bpy）₃²⁺之间存在能量转移,导致ECL信号淬灭,从而实现了邻苯二酚的灵敏检测,线性响应范围为5.0×10^-9~1.0×10^-5 mol·L^-1,检出限为1.5×10^-9 mol·L^-1.该传感器用于河水中邻苯二酚的检测,结果令人满意.同时,传感器也表现出良好的重现性和稳定性.     

分级纳米多孔铋电化学传感器用于镉离子的检测

采用电化学方法实现对水溶液中重金属离子的超灵敏检测是分子生物学、环境学和医学等领域长期研究的课题，而如何制备具有高比表面积和快速响应特性的电极则是电化学痕量检测的关键。以双相合金Mg₇₉Bi₂₁条带为前驱体，通过一步脱合金法制备了分级纳米多孔铋（hierarchical nanoporous bismuth, HNBi）电极，结合方波阳极溶出伏安法，实现了对水溶液中Cd²⁺的快速检测，检测极限低于10⁻⁹ mol/L，线性动态响应范围介于10⁻⁸ mol/L和10⁻⁶ mol/L之间。HNBi电极绿色环保，在电化学检测领域显示出巨大的应用潜力。     

镍渣表面理化特性及对Pb2+、Cu2+的吸附研究

利用多种表征手段对镍渣的组成和表面特性进行分析,证实了镍渣具备吸附废水中重金属的能力。本实验所采用的水淬二次镍渣中含有含量较高的SiO₂、Al₂O₃、CaO、MgO等活性成分,且具备由不同聚合度的Si-O四面体、Al-O四面体或Al-O八面体组成的岛状、链状或网状骨架结构,能够通过离子交换和专性吸附去除溶液中的重金属离子。此外,镍渣粉体表面的碱中心可以为金属阳离子提供有效的吸附位点,且表面在pH=4~12的范围内均带负电,这些都有利于金属阳离子的吸附。镍渣粉体对模拟废液中的Pb²⁺、Cu²⁺吸附实验结果显示,其对废液中的Pb²⁺、Cu²⁺均表现出较好的吸附效果,且对Pb²⁺表现出更好的选择性吸附效果。     

循环伏安法对邻苯二酚的测定

将氧化石墨烯分散液及谷氨酸的混合液用循环伏安法修饰在玻碳电极上,制备出聚L-谷氨酸/石墨烯修饰电极。通过循环伏安法,对邻苯二酚在此修饰电极上的电化学行为进行研究。结果表明,在最佳优化的实验条件下,邻苯二酚在0.507 V处出现一对氧化还原峰,且浓度在2.00×10^-6mol/L~4.00×10^-4mol/L范围内表现出良好的线性关系,检出限为6.7×10^-7mol/L。利用该方法测定样品中的邻苯二酚,结果令人满意。     

中东孔隙型低渗灰岩储层酸液体系缓速性

酸液的缓速性是影响酸液有效作用距离的关键因素,是优选酸压工作液的重要依据。采用旋转岩盘进行了普通盐酸、胶凝酸和乳化酸与伊朗雅达油田Sarvak储层灰岩岩心的酸岩反应实验,构建了反应动力学方程和变温动力学方程。结果表明,普通盐酸的反应速率明显快于胶凝酸和乳化酸,温度对反应速率影响显著,温度越高,反应速率越快。95 ℃下,普通盐酸、胶凝酸和乳化酸的反应速率常数分别为6.1745×10_^-5 (mol/L)_^-0.8543/(cm_².s)、7.8397×10_^-6 (mol/L)_^-0.6260/(cm_².s)、7.6348×10_^-7 (mol/L)_^-1.3931/(cm_².s),反应级数分别为0.8543、0.6260、1.3931;酸液浓度为20 %时,反应活化能分别为19.31 kJ/mol、25.34 kJ/mol、31.53 kJ/mol;乳化酸的缓速性相对最好,其次为胶凝酸,预测乳化酸和胶凝酸的有效作用距离更大;同时乳化酸反应级数较大,现场配液时需要考虑浓度对反应速率的影响。     

Na+-K+-ATP酶的π-演算语义及验证

给出了Na⁺-K⁺-ATP酶跨越细胞膜同时主动向胞内运转钾离子和向胞外运转钠离子这一生化过程的π-演算模型及该模型的Spin验证. 证明了用过程代数的方法表示以“相互通讯”和“可移动”为主要特征的生物系统并模拟其行为的可行性.      

Effect of MTEC1 on the functional expression of TCRaβ+ 3G11− 6C10− CD4+ CD8− thymocyte subset

A murine CD4⁺ thymocyte subset with phenotype of TCRαβ⁺ 3G11⁻ 6C10⁻ CD4⁺ CD8⁻ CD69^+/- HSA^med/lo contains the cells in relatively functional matured status. The functional property of the cells in this subset is characterized by the unique pattern of cytokine production at transitional stage from Th0 to Th2 type with the latter being the dominant type. After being co-cultured with murine thymic medullary epithelial cell line (MTEC1) cells, a murine thymic medullary type epithelial cell line, the TCRαβ⁺ 3G11⁻ 6C10⁻ CD4⁺ CD8⁻ CD69^+/- HSA^med/lo thymocytes, has exhibited significantly higher levels of proliferation capability and IL-6 production, whereas the production of IL-4 and IL-10 is suppressed after co-culturing with MTECl. By contrast, MTECl could not induce thymocytes to secrete Thl type of cytokines. The results suggest that MTECl can regulate functional status of this thymocyte subset and induce them to develop into a specialized Th2 subset.     

Effects of La3+ and Gd3+ on Ca2+ influx in rat hepatoma H-35 cells

Effects of La³⁺ and Gd³⁺ on Ca²⁺ influx were investigated in rat hepatoma H-35 cells by measuring the initial rate of⁴⁵Ca²⁺ uptake. It was found that the maximum initial rate of Ca²⁺ uptake was increased six-to ten-fold at low concentrations of La³⁺ and Gd³⁺. Kinetic analyses by measuring the initial rate of Ca²⁺ influx at different external Ca²⁺ concentrations indicated the existence of two intracellular exchangeable components in the basal Ca²⁺ system, with low and high affinities for Ca²⁺, and only one class of Ca²⁺ binding sites was observed in the La³⁺-or Gd³⁺-treated cells. For high affinity, La³⁺ and Gd³⁺ increased both kinetic parametersK _m andV _max of basai Ca²⁺ influx. La³⁺ and Gd³⁺ compete directly with Ca²⁺ for Ca²⁺ binding site for low affinity. The kinetics is competitive.     

Functional maturation of two murine medullary-type CD8SP thymocytes

TCRαβCD4-CD8+ thymocytes are heterogeneity. They may undergo phenotypic and functional maturation within thymic medulla. Medullary-type CD8SP thymocytes were divided into seven subsets based on phenotypic analysis, and their precursor-progeny relationship along with the differential pathway was also delineated. To further testify the validity of the maturation pathway, we purified 6C10-CD69+ cells representing the early stage and 6C10-Qa-2+ cells representing the later stage among medullary-type CD8SP thymocytes and compared their functional maturation levels. CD8+ T cells of spleen were used as the control. It is shown that there is no obvious difference of proliferation ability among these three subsets; however, intracytoplasmic cytokine assay shows that there is a hier archy of IFN-γ and TNFα secretion among these subsets, strikingly comparable to their phenotypic status among medullary type CD8SP thymocytes. The bioassays of IL-2 and IFN-γ in culture supernatant give the similar results.     

Export of particulate organic carbon estimated from234Th-238U disequilibria and its temporal variation in the South China Sea

Activities of²³⁴Th and nutrient concentrations in the upper 500 m water column were measured at a time-series station in the South China Sea over a time span of 12.3 d. Results showed a reduction of dissolved²³⁴Th and an overall increase of particulate²³⁴Th during the period. Meanwhile, activities of total²³⁴Th kept fairly constant, implying rapid transformation of²³⁴Th between the dissolved and particulate forms. Vertical profiles of total²³⁴Th showed evident deficit of²³⁴Th relative to²³⁸U in the upper 500 m water column. Using an irreversible steady-state model of thorium scavenging, export fluxes of particulate organic carbon (POC) corresponding to time pointsT ₁ andT ₂ were estimated to be 46.5 and 13.1 mmolC · m⁻² · d⁻¹. It was demonstrated that the estimation of POC export was greatly dependent on the POC/²³⁴Th_P ratios and the bias caused by the different models of²³⁴Th scavenging, however, was considered to be of minor importance.     

Oxygen isotopic (17O-18O) heterogeneity in Archaean continental nucleus, North China Craton

The oxygen isotopic data for amphibolites from Archaean continental nucleus, North China Craton indicate that ( i ) the evolving lines structured by the data are parallel to the geoselenic evolving line, which means that the parent materials of these continental nucleus originated from solar matter; ( ii ) different intercepts for these evolving lines manifest that oxygen isotopic compositions of different continental nucleus are heterogeneous, which means that these continental nucleuses originated from different parent resources with different original compositions.     

Determination of specific activity of230Th in uranium ore samples

A new method suitable for determining specific activity of²³⁰Th in uranium ore samples is built. The method is characterized by adding the²³⁰Th/²³²Th standard dilution agent with lower activity ratio (Its²³⁰Th/²³²Th activity ratio and²³⁰Th have been known) to the samples and using isotopic dilution analysis. The method can be applied to analyses of²³⁰Th specific activity in various²³⁰Th/²³²Th activity ratio samples. The precision can also be improved.     

含Sr2+和Bi3+有机杂化体的合成及其光降解罗丹明B

采用溶剂热法在N,N-二甲基甲酰胺溶液中合成了不同摩尔比例的SrCl_2和Bi(NO_3)_3(分别为5%,10%,30%,50%,80%)与对苯二甲酸形成的含Sr~(2+)和Bi~(3+)有机杂化体,并在紫外可见光照射下对其进行了罗丹明B降解活性的评价.结果表明:杂化体在紫外可见光下对RhB降解活性良好,其中SrCl_2摩尔比例10%掺杂的催化剂光降解活性最佳,这归结于其在紫外区域对光有很好的吸收及光生电子和空穴能有效地分离.双金属离子能协同调节有机杂化体的光催化活性.     

Laser probe40Ar/39Ar dating of mica on the deformed rocks from Altyn Fault and its tectonic implications, western China

The samples of Caledonian mylonitized granite and Jurassic meta-sedimentary rocks were collected in the north of Dangjinshan Pass, Qaidam gate fault-valley and Gesi fault-valley. Detailed studies under the microscope and electronic microscope suggest that all the samples contain the syntectonic-growing minerals such as white mica, chlorite, sericite, biotite, etc. By dating these minerals, we got a group of ⁴⁰Ar/³⁹Ar laser probe isochronal ages of 89—92 Ma and apparent ages of (46.6±6.4) Ma. The ages ranging from 97 to 46 Ma were reported for the first time in the isotopic dating researches of the Altyn Fault. The isochronal age group of (98—89) Ma indicates that a ductile strike-slip event, with low-grade metamorphism, began in late Cretaceous. This suggests that the strike-slip movement of the Altyn Fault should be related to the formation of the so-called west tectonic syntaxis in the Nepal-western Kunlun area.     

Effect of fatty acids on polyamine contents and Na+/H+ antiport activity in PM vesicles isolated from roots of barley under salt stress

With 200 mmol/L NaCl treatment on barley cultivar “Jian 4” (Hordeum vulgare L. cv. J4) seedlings for 6 d, the contents of covalently and noncovalently conjugated polyamines (PAs) and activities of H⁺-ATPase in plasma membrane (PM) vesicles isolated from the roots decreased remarkably. Moreover, the activity of Na⁺/H⁺ antiport was detected first in PM vesicles. The results showed that the decrease in the contents of membrane phospholipid, noncovalently conjugated PAs and activity of H⁺-ATPase caused by NaCl could be restored partially by application of 1 mmol/L stearie acid (C_16:0) and linoleic acid (C_18:2), and C_18:2 was more effective than C_16:0 In addition, a reduction in the contents of covalently conjugated PAs was only reversed partially in the presence of C_18:2 Furthermore, Na⁺/H⁺ antiport activity was strengthened by exogenous C_16:0 and C_18:2 and C_18:2 was more effective than C_16:0. The correlative analysis suggested that, after application of C_16:0 and C_18:2 under salt stress, there was a significant positive correlation existing among phospholipid content, noncovalently conjugated PA levels, H⁺-ATPase activities and Na⁺/H⁺ antiport activities, indicating that one of the mitigative mechanisms of exogenous fatty acids on salt injury was to improve membrane phospholipid and PA contents, leading to an enhance in membrane integrity and a change in charge status of PM vesicles, so the activity of membrane-associated enzyme H⁺-ATPase was increased and synthesis of Na⁺/H⁺ antiport protein was activated.