将"物理思想"融入物理实验教学改革的探索与实践

从当前物理实验教学改革、培养有创新能力工程技术人才的角度,论述了理解物理实验中的物理思想和认识它的重要性。     

Insights into the surface property and blood compatibility of polyethersulfone/polyvinylpyrrolidone composite membranes: toward high‐performance hemodialyzer

Applications of blood purification membranes are fuelled by diverse clinical needs, such as hemodialysis, hemodiafiltration, hemofiltration, plasmapheresis, and plasma collection. For clinical usage, the adding of polyvinylpyrrolidone (PVP) is the general protocol for the design of antifouling and antithrombotic properties integrated artificial membranes. In the present work, to insight into the detailed surface properties and blood compatibilities of the PVP blended composite membranes, we synthesized a series of PVP polymers with different molecular weights using reversible addition fragmentation chain transfer polymerization and designed a series of polyethersulfone (PES)/PVP composite membranes by a physically blending method. The effects of PVP molecular weights and blending ratios on the surface properties and the blood compatibilities of the composite membranes were investigated in detail. The surface attenuated total reflection Fourier transform infrared spectra and scanning electron microscopy pictures indicated that the PVP was successfully immobilized into the membranes, and the composite membranes exhibited morphology transformation from finger‐like structure to sponge‐like structure, which indicated that the composite membrane had tunable porosity and permeability by adding PVP. The blood compatible tests revealed that the composite membranes showed increased hydrophilicity, decreased plasma protein adsorption, suppressed platelet adhesion, and prolonged blood clotting time compared with pristine PES membrane. These results indicated that the PES/PVP composite membranes exhibited enhanced antifouling and antithrombotic properties than the pristine PES membrane. Meanwhile, the results also suggested that the composite membranes with larger molecular weight PVP and higher blending ratios might show better blood compatibility. Copyright © 2014 John Wiley & Sons, Ltd.     

The study of ZnAl and ZnFe layered double hydroxide on the catalytic dechlorination and fire safety of polyvinyl chloride

Journal of Thermal Analysis and Calorimetry - The effect of OZnAl-LDH and OZnFe-LDH on the catalytic dechlorination, thermal decomposition and smoke suppression of polyvinyl chloride (PVC) during...     

Gd, N-codoped trititanate nanotubes: Preparation, characterization and photocatalytic activity

Trititanate nanotubes were prepared using hydrothermal method and then co-doped with Gd³⁺ and N through ion-exchanging with H⁺. They were characterized by X-ray photoelectron spectra (XPS), high-resolution transmission electronmicroscopy (HRTEM), X-ray diffraction (XRD), UV-vis diffusion reflection spectra (UV-vis DRS) and photoluminescence (PL) spectra. The photocatalytic activities were investigated with Rhodamine B as the model pollutant. The results indicated that synergistic reaction occurred when codoping with Gd³⁺ and N and the photocatalytic activities of TiO₂ were enhanced significantly under visible light irradiation.     

聚紫精-脂肪酸盐表面活性剂复合物的组装合成及相行为研究

通过Menshutkin反应合成聚(对亚二甲苯基-4,4'-联吡啶二溴)(PXV)半刚性链聚紫精,采用等量混合法将聚紫精与系列不同碳链长度的阴离子表面活性剂脂肪酸钠Cn-1COONa(n=10,12,14,16,18)组装制备聚电解质-表面活性剂(PXV-Cn)复合物,运用DSC,TGA,XRD,FTIR等表征手段初步考察复合物的超分子结构及相行为.基于FTIR谱学分析特征、小角与广角变温XRD数据以及DSC热分析焓变的定量计算结果,表明半刚性主链聚紫精和脂肪酸盐极性头基组成的极性层与侧链烷烃非极性层交替排列形成层状超分子结构,其中烷烃链靠近极性端约8个亚甲基处于无定型态,其余碳链则形成结晶相.最短的PXV-C10形成少量规整度较低的三斜晶βT,n≥16以上的长碳链复合物则以六方相αH为主,其它中等长度侧链脂肪酸盐复合物则为多种结晶形式共存.随着碳链长度n的增加,侧链结晶熔点Tm升高,n≥16的长碳链复合物表现出随温度变化的可逆结晶相态变化.且这类聚紫精-表面活性剂复合物表现出高于200℃的热稳定性.     

蒙卡程序计算临界基准题测试检验ENDF/B-Ⅷ.0核数据库

采用MCNP程序和ENDF/B-Ⅶ.1,ENDF/B-Ⅷ.0核数据库,对119个模型构成的临界基准题进行了临界计算测试检验。此临界基准题模型包含²³³U、高浓铀、中浓铀、低浓铀和钚材料的临界实验系统,中子能量覆盖了快中子、中能中子和热中子能谱。采用ENDF/B-Ⅷ.0核数据库的计算有效增殖因子keff结果与基准实验结果相对偏差的均值和标准差分别为-68.98×10^-5和407.88×10^-5,检验计算keff结果与基准实验结果的偏差与基准实验不确定度比值在1σ（σ为标准不确定度）以内、1σ～3σ区间和大于3σ的数量分别为107,9和3个;将此结果与相同条件下ENDF/B-Ⅶ.1核数据库的计算结果进行了比较,表明ENDF/B-Ⅷ.0核数据库对临界计算更准确,与实验模型结果符合更好。     

Measurement-induced-nonlocality via the Unruh effect

Treated beyond the single-mode approximation, Measurement-Induced-Nonlocality (MIN) is investigated for both Dirac and Bosonic fields in non-inertial frames. Two distinct differences between the Dirac and Bosonic fields are: (i) the MIN for Dirac fields persists for any acceleration, while the quantity for Bosonic fields does decay to zero in the infinite acceleration limit; (ii) the dynamic behaviors of the MIN for Dirac fields is quite different from the Bosonic fields case. Besides, we also study the nonlocality for Dirac fields and find that the MIN is more general than the quantum nonlocality related to violation of Bell’s inequalities. Meanwhile some discussions of geometric discord are presented too.     

Femtosecond laser ablation of silicon in air and vacuum

Femtosecond(fs) pulse laser ablation of silicon targets in air and in vacuum is investigated using a timeresolved shadowgraphic method. The observed dynamic process of the fs laser ablation of silicon in air is significantly different from that in vacuum. Similar to the ablation of metallic targets,while the shock wave front and a series of nearly concentric and semicircular stripes,as well as the contact front,are clearly identifiable in the process of ablation under 1×10 5 Pa,these phenomena are no longer observed when the ablation takes place in vacuum. Although the ambient air around the target strongly affects the evolution of the ablation plume,the three rounds of material ejection clearly observed in the shadowgraphs of fs laser ablation in standard air can also be distinguished in the process of ablation in vacuum. It is proven that the three rounds of material ejection are caused by different ablation mechanisms.     

基于微阵列聚焦电泳的糖尿病血样临床阳离子交换高效液相色谱图中血红蛋白A3峰位置推测

血红蛋白A_1c(HbA_1c)是糖尿病诊断的关键生物标志物,目前其常用的分析方法为阳离子交换高效液相色谱法(CX-HPLC, 5/50 mm分离柱),此方法虽然具有稳定、快捷与自动化等众多优点,但临床CX-HPLC(VARIANT Ⅱ system)谱图中仍存在未知峰,尤其干扰HbA_1c准确测定的谷胱甘肽化血红蛋白A₃(HbA₃)在色谱图中的相对位置仍不清楚。针对这一问题,该文以人新鲜血液为样本,首先利用低分辨CX-HPLC对血样进行分析,提示未知峰P3存在。然后通过微阵列等电聚焦(IEF)电泳和高分辨阳离子交换HPLC(Mono-S 5/50 mm分离柱)对血样的主要血红蛋白(Hb)成分进行分析,提示未知峰P3为HbA₃峰。随后,通过血红蛋白谷胱甘肽化实验,利用HbA_1c峰降低、HbA₃峰明显增强这一信息,进一步推测未知峰P3即是HbA₃峰,其在CX-HPLC中的保留时间在1.50 min左右。最后,结合前期研究讨论了体内应激情况下Hb谷胱甘肽化对HbA_1c检测的影响。该研究丰富了CX-HPLC的未知峰P3的色谱信息,为更精准诊断糖尿病提供了有价值的参考。     

纯水中氧化石墨烯的超声裁剪及机理研究

采用超声在纯水中对氧化石墨烯(GO)进行裁剪, 研究了超声时间对GO片层尺寸、 官能团种类和含量的影响, 探讨了超声裁剪GO的机理. 用原子力显微镜(AFM)和透射电子显微镜(TEM)对产物进行观测, 结果表明, 随着超声时间延长, GO片层平均直径从2000 nm减小至200 nm. 红外光谱(FTIR)、 X射线光电子能谱(XPS)及热分析结果表明, 随着超声时间延长, GO的含氧官能团种类没有变化, 但是GO含氧官能团总量逐渐升高, 其中环氧基团含量逐渐下降, 羧酸基团含量变化不大, 酮基基团含量先下降后升高, 羟基基团含量先升高后下降, 醚氧基团含量逐渐升高. 基于上述结果, 提出了超声裁剪GO的机理: 超声空化现象形成的剪切力使GO的碳碳键、 环氧、 酮基基团断裂, GO片层尺寸变小; 在超声诱导下水分子形成的羟基自由基和氢自由基与片层上断裂形成的碳自由基结合生成羟基或醚氧基团, 未发生水解的碳自由基形成新的碳碳键, 长时间的超声作用还会使羟基基团发生断裂并转化成酮基基团. 利用超声在纯水中裁剪GO的条件温和, 不使用其它化学试剂, 可以有效控制GO片层尺寸, 是一种具有应用前景的二维材料裁剪技术.