配合物[Ni（H2B（pyrazolyl）2）2]的非等温热分解动力学研究

在甲醇溶液中用Ni(CH3COO)2.4H2O和NaH2B(pz)2常温下合成出了配合物[Ni(H2B(pz)2)2](pz=pyrazolyl),并用元素分析、红外光谱和X射线衍射等对配合物的结构进行了表征,对此配合物进行了非等温热分解动力学研究.采用了微分Achar和积分Coats-Redfern法分别拟合出配合物2个热分解阶段的动力学方程及相应的动力学参数.配合物第一热分解阶段可能的机理为三维扩散,球形对称,其动力学方程为dα/dT=3(A/β)e-E/RT[(1-α)-1/3-1]-1/2.配合物第二热分解阶段可能的机理为相边界反应,圆柱形对称(n=1/2),其动力学方程为dα/dT=2(A/β)e-E/RT(1-α)1/2.2个反应阶段的表观活化能平均值分别为260.87和176.27kJ/mol,lnA的平均值分别为65.65和37.11s-1.     

基于电喷雾电离质谱的人肝癌细胞HepG2与正常肝细胞L02的N-糖链的定性定量比较

以培养的原发性肝癌细胞HepG2和正常肝细胞L02为研究对象,采用细胞裂解液提取总蛋白,用PNGase F酶解释放N-糖链,以微晶纤维素柱结合石墨碳柱纯化分离N-糖链,通过电喷雾电离质谱(ESI-MS)和串联质谱(MS/MS)对N-糖链进行序列鉴定,以β-环糊精为内标对2种细胞系的N-糖链进行了定量比较分析.结果表明,在肝癌细胞系HepG2和正常细胞系L02中共检测到26种N-糖链,与L02相比,HepG2的大多数高甘露糖型糖链、唾液酸化糖链和岩藻糖基化糖链的数量都明显升高,其中有15种糖链在数量上具有极显著性差异(p0.01),1种糖链具有显著性差异(p0.05).本研究为进一步探索肝癌中各类N-糖链的表达特点及发现早期肝癌糖链标志物提供了参考.     

碳纤维基PtPb阳极催化剂的制备及其电催化性能

以静电纺丝技术与烧结工艺相结合的方式制备了碳纤维基PtPb纳米催化剂,并采用X射线衍射（XRD）、红外光谱（FT-IR）、扫描电镜（SEM）等分析测试手段对其进行了表征。结果表明,在预氧化温度为300 ℃、碳化温度为800 ℃的条件下,所制备的PtPb阳极纳米催化剂结晶程度好、比表面积大,粒径约为3.05 nm,催化活性颗粒均匀分散在多孔碳纤维骨架上。采用循环伏安法（CV）及交流阻抗（EIS）评价了该催化剂对乙醇氧化反应的电催化性能。结果表明,最大峰电流密度达到125 mA/cm²,电荷转移电阻相较于700 ℃下降了近60%。     

Solvent extraction of U(VI) by trioctylphosphine oxide using a room-temperature ionic liquid

The unique physical and chemical properties of room-temperature ionic liquids(RTILs) have recently received increasing attention as solvent alternatives for possible application in the field of nuclear industry, particularly in liquid-liquid separations of radioactive nuclides. We investigated solvent extraction of U(VI) from aqueous solutions into a commonly used ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide([C4mim][NTf2]) using trioctylphosphine oxide(TOPO) as an extractant. The effects of contact time, TOPO concentration, acidity, and nitrate ions on the U(VI) extraction are discussed in detail. The extraction mechanism was proposed based on slope analysis and UV-Vis measurement. The results clearly show that TOPO/[C4mim][NTf2] provides a highly efficient extraction of U(VI) from aqueous solution under near-neutral conditions. When the TOPO concentration was 10 mmol/L, the extraction of 1 mmol/L U(VI) was almost complete( 97%). Both the extraction efficiency and distribution coefficient were much larger than in conventional organic solvents such as dichloromethane. Slope analysis confirmed that three TOPO molecules in [C4mim][NTf2] bound with one U(VI) ion and one nitrate ion was also involved in the complexation and formed the final extracted species of [UO2(NO3)(TOPO)3]+. Such a complex suggests that extraction occurs by a cation-exchange mode, which was subsequently evidenced by the fact that the concentration of C4mim+ in the aqueous phase increased linearly with the extraction percent of U(VI) recorded by UV-Vis measurement.     

基于思维模型建构的高三化学复习教学*—— 以“平衡原理的应用”为例

以高三复习课“平衡原理的应用”为例,通过真实情境的剖析让学生感知模型,引导学生分析归纳提炼模型,并进行针对练习运用模型,变式训练体会模型,让学生在实践中以模型思维为突破,深入领悟建构模型的实质,有序解决复杂化学问题,提升科学思维能力,发展化学学科核心素养。     

Thermal- and Light-driven Metathesis Reactions Between Different Diselenides

Thermal- and light-driven diselenide metathesis reactions with different types of diselenides are investigated systematically. Their exchange reaction rates and equilibrium conversions are compared in the aspects of the different diselenide structures, activation conditions and solvents. As a result, the metathesis reactions between diselenide small molecules are demonstrated with high dynamic and sensitive features, which can be broadly tuned by varying the electron affinity and aromaticity of the diselenide substituents and external conditions(e.g., solvent, stimulus mode). The current work thus will not only advance our understanding on diselenide metathesis chemistry, but also promote concrete and impactful studies in selenium-containing materials.     

Development of the Self-doping Porous Carbon and Its Application in Supercapacitor Electrode

The massive discharge of biomass wastes not only causes waste of resources, but also pollutes the environment. Therefore, converting biomass wastes into carbon materials is an effective way to solve the above problems. Here, using biomass waste pig nails as raw materials and K₂CO₃ as chemical activators, the N-doped porous carbon(KPNC) is prepared by direct pyrolysis. As an electrode for supercapacitors, the electrochemical tests of KPNCs showed that they exhibited good electrochemical performance and excellent cycling stability. When the current density is 0.2 A/g, the specific capacitance is up to 344.6 F/g. Moreover, it still maintains 97.6% initial capacitance retention after 2000 cycles at a high current density of 5 A/g. Above exceptional electrochemical performances may be ascribed to an appropriate porous structure(S_micro/S_total=80.31%, V_micro/V_total=76.19%), high nitrogen contents(4.44%, atomic fraction), oxygen contents(9.13%, atomic fraction) as well as small internal resistance. The above experimental results show that the conversion of pig nails to porous carbon can reduce the waste of resources and alleviate environmental pollution.     

肿瘤乏氧靶向响应的罗丹明荧光探针及其成像介导手术治疗

基于罗丹明的良好荧光性能, 经化学偶联反应制备并表征了一个偶氮乏氧特异响应的“Off-On”型荧光成像探针(FY-4). 从分子层面证实了其荧光“Off-On”性能和响应机制; 在L02正常细胞及4T1, HeLa和A549肿瘤细胞层面考察了其对受试细胞株的毒性和不同乏氧时间的荧光成像性能; 再利用4T1肿瘤模型, 分别以肿瘤原位注射和尾静脉注射的方式考察了其荧光成像性能, 并探究了其荧光成像介导切除肿瘤性能, 最后还考察了FY-4的生物安全性. 结果表明, FY-4有高的肿瘤乏氧靶向特异“关-开”响应的荧光成像差异显影及荧光成像介导切除肿瘤的潜能, 结合其良好的光物理性能、 生物安全性和明晰的给药时间等特性, 有望为生物医学荧光成像介导肿瘤切除提供新的研究工具.