稀土铕荧光聚合物的制备及与DNA的相互作用

含稀土金属的聚合物既保留了稀土金属的独特性质,又具有聚合物的优点,成为材料科学领域研究的热门之一。文中用含铕稀土配合物单体Eu(AA)3Phen、2-甲基丙烯酰氧乙基-三甲基氯化铵、N-异丙基丙烯酰胺成功合成出阳离子型稀土荧光聚合物,并用核磁共振谱、凝胶渗透色谱、荧光光谱、琼脂糖凝胶电泳、Zeta电位及粒径分析、透射电镜等对其结构、性能进行了表征。结果表明,产物结构明确,在594 nm和618 nm处的具有特征荧光发射,与DNA能够通过静电作用相互结合,特征荧光发射强度不断增强,形成的复合物粒径从246.8 nm逐渐增大到579.7 nm;而Zeta电位逐渐从41.2 mV降低到-12.8 mV,并能使DNA在琼脂糖凝胶电泳中的运动受到阻滞。     

异相膜NIMTE在空气能量回收装置中使用效果试验研究

通过对国产纸膜和日本滤纸膜材料的分析研究,研制出NIMTE异相膜,并在空气能量回收装置使用过程中对风压、空气流量、热流方向与热交换效率、回收能量、能效及安全性的关系进行分析,设计出能够更好发挥异相膜使用效果的传热膜机芯,有效提高空气能量回收装置的综合性能。     

空调系统能效指标探讨

针对目前空调系统中各种能效指标表示符号不一致的现象,分析能效比理论极限,并对各种能效指标进行比较,进而使不同能效指标的概念及应用逐渐清晰化。     

Enhanced and Differential Capture of Circulating Tumor Cells from Lung Cancer Patients by Microfluidic Assays Using Aptamer Cocktail

Collecting circulating tumor cells (CTCs) shed from solid tumor through a minimally invasive approach provides an opportunity to solve a long‐standing oncology problem, the real‐time monitoring of tumor state and analysis of tumor heterogeneity. However, efficient capture and detection of CTCs with diverse phenotypes is still challenging. In this work, a microfluidic assay is developed using the rationally‐designed aptamer cocktails with synergistic effect. Enhanced and differential capture of CTCs for nonsmall cell lung cancer (NSCLC) patients is achieved. It is also demonstrated that the overall consideration of CTC counts obtained by multiple aptamer combinations can provide more comprehensive information in treatment monitoring.     

石墨烯表面改性及其在聚合物导电复合材料中的应用研究

石墨烯作为一种新型的二维碳纳米材料,引起了科学家们极大的兴趣。其中石墨烯/聚合物复合材料具有优异的导电性能,广泛应用于电子、电气等领域。石墨烯片层易于团聚,在聚合物基体中分散不均匀,严重影响了石墨烯/聚合物复合材料的导电性能,需要对石墨烯及其衍生物进行表面改性。表面改性能有效地提高石墨烯在聚合物基体中的分散性,改善石墨烯与聚合物基体的相容性。文中介绍了石墨烯的共价改性(亲核取代反应、亲电取代反应、缩聚反应)和非共价改性(表面活性剂吸附、杂化修饰)的方法,以及对石墨烯/聚合物复合材料导电性的影响,总结了2种改性法的优缺点,最后展望了石墨烯改性及其在聚合物导电复合材料应用方面的研究方向。     

氟化铵-盐酸法提纯隐晶质石墨工艺研究

为了提高隐晶质石墨的固定碳含量,扩大隐晶质石墨的应用范围,采用湖南郴州地区的隐晶质石墨为原料,用氟化铵-盐酸法对其进行纯化处理。研究了氟化铵的用量、反应温度、液固比以及反应次数对隐晶质石墨固定碳含量的影响,确定了氟化铵-盐酸法提纯隐晶质石墨的最佳工艺条件。结果表明:在氟化铵的含量为45%,液固比为3∶1,恒温70℃反应2h,重复5次的条件下能够将隐晶质石墨的固定碳含量从83.08%提高到99.47%。研究表明氟化铵-盐酸法可以有效提高隐晶质石墨的固定碳含量。     

Calibration method for a photoelastic modulator with a peak retardation of less than a half-wavelength

A new calibration method for a photoelastic modulator is proposed. The calibration includes a coarse calibration and a fine calibration. In the coarse calibration, the peak retardation of the photoelastic modulator is set near 1.841 rad. In the fine calibration, the value of the zeroth Bessel function is obtained. The zeroth Bessel function is approximated as a linear equation to directly calculate the peak retardation. In experiments, the usefulness of the calibration method is verified and the calibration error is less than 0.014 rad. The calibration is immune to the intensity fluctuation of the light source and independent of the circuit parameters. The method specially suits the calibration of a photoelastic modulator with a peak retardation of less than a half-wavelength.     

Facile synthesis of carbon coated LiFePO4 nanocomposite with excellent electrochemical performance through in situ formed lithium stearate pyrolysis route

Carbon coated LiFePO₄ (LiFePO₄/C) nanocomposite is successfully synthesized at a comparatively low temperature (400 °C) via a pyrolysis process of in situ formed lithium stearate. The obtained products are characterized by X-ray diffraction, electron microscopy, thermogravimetry, infrared and X-ray photoelectron spectroscopy. Experimental results indicate that the in situ formed lithium stearate can decompose at ∼290 °C, which is beneficial for the formation of carbon coating and reduction of Fe³⁺ species, and then the crystallized LiFePO₄/C nanocomposite can be formed at 400 °C without other intermediate products. As cathode material of Li-ion battery, the obtained LiFePO₄/C nanocomposite exhibits a good rate and cycling performance with a high discharge capacity of ∼160 mAh g⁻¹ (>94% theoretical capacity of LiFePO₄) at a current density of 1 C (170 mA g⁻¹), and ∼96% of its initial capacity can be retained after 200 charging/discharging cycles. Even at a high current density (10 C), the LiFePO₄/C nanocomposite still presents a discharge capacity as high as ∼100 mAh g⁻¹. The excellent electrochemical performances of the present LiFePO₄/C nanocomposite mainly originate from the good crystallinity, small particles and enhanced electronic conductivity of the materials coated and linked by carbon layers.