Dye-sensitized solar cells based on electrospun poly(vinylidenefluoride-co-hexafluoropropylene) nanofibers

Poly(vinylidenefluoride-co-hexafluoropropylene) (PVDF-HFP) nanofibers were prepared by the electrospinning method and used as polymer electrolytes in dye-sensitized solar cells (DSSCs). The electrolyte uptake and ionic conductivity of electrospun PVDF-HFP nanofibers with different diameters changed significantly, regardless of the nanofiber thickness. The PVDF-HFP nanofibers prepared from a 15 wt% spinning solution showed high ionic conductivity (1.295 S/cm) and electrolyte uptake (947 %). DSSCs based on the 15 wt% PVDF-HFP nanofiber electrolyte showed an electron transit time of 6.34 × 10^?3 s, electronic recombination time of 5.88 × 10^?2 s, and conversion efficiency of 3.13 %. Thus, we concluded that the electrospun PVDF-HFP nanofibers can be used as polymer electrolytes in flexible DSSCs as well.     

The β-nucleating effect of wollastonite-filled isotactic polypropylene composites

Wollastonite (W) with β-nucleating effect (β-W₁₀₀) for iPP crystallization was obtained through reaction between Ca²⁺ in wollastonite and pimelic acid (PA) and the β-iPP composites filled by different content of β-W₁₀₀ were prepared. The effect of PA and wollastonite contents on β-nucleation, crystallization and melting behavior, and crystalline morphology of W and β-W₁₀₀-filled iPP composites was investigated by differential scanning calorimetry (DSC), wide-angle X-ray diffraction, and polarizing optical microscopy. The results indicated that incorporation of W and β-W₁₀₀ increase the crystallization peak temperature of iPP due to its heterogeneous nucleating ability. And iPP/W composites predominantly crystallize in the α-phase iPP and iPP/β-W₁₀₀ composites in the β-phase iPP. The results of DSC multi-scanning in same and different melting temperatures showed that β-W₁₀₀ not only has strong heterogeneous β-nucleating effect but also DSC multi-scanning in same and different melting temperatures has no influence on the heterogeneous β-nucleating effect of β-W₁₀₀. The β-iPP containing high wollastonite content with high β-phase content can be easily prepared.     

Low-Temperature Sintering of (K0.5Na0.5)NbO3 Piezoelectric Ceramics

(K_0.5Na_0.5)NbO₃ piezoelectric ceramics can be sintered at a temperature as low as 750 °C for 5 h by incorporating Li₂CO₃ + Bi₂O₃ + ZnO as the sintering aid, whereas the conventional sintering temperature is around 1,100 °C. The optimal “soft” piezoelectric properties are obtained for ceramics sintered at 850 °C for 5 h. The dielectric permittivity (ε), piezoelectric coefficient (d ₃₃), electromechanical coupling (k _p) and mechanical quality factors (Q _m) of (K, Na)NbO₃ modified with 5.5 wt% sintering aids are 1,436, 90 pC/N, 0.3 and 10, respectively. These values are similar to the values obtained for (K_0.5Na_0.5)NbO₃ ceramics sintered above 1,100 °C. The underlying mechanism for abrupt change of dielectric permittivity is explained.     

紫外荧光法测定复合肥中总硫含量

建立了紫外荧光法检测复合肥中总硫含量的方法,样品前处理中使用无机酸一盐酸溶解试样。标准工作曲线相关线性良好,相关系数r=0．9994,测得两批试样的相对标准偏差分别为0．013％、0．016％,该方法能快速准确检测复合肥中总硫含量。     

Modeling and experimental verification of radiative transfer of a flat‐plate photoreactor with immobilized photocatalyst

A cost‐effective design of photocatalytic reactor needs efficient contact of the polluted substance with the solid catalyst while uniformly irradiating the solid catalyst with light. In the present paper, an immobilized photocatalyst comprising TiO₂ coated on Pyrex‐glass‐coils (abbreviated hereafter as TGC) was developed, and a flat‐plate photocatalytic reactor packed with TGC was designed. The reactor has some advantages such as low pressure drop, intensification of mass transfer; relatively uniform distribution of light radiation; high ratio of illuminated catalyst surface area to volume, and is flexible enough for large‐scale application. The radiation intensity distribution and the two‐flux model parameters were measured, and the two‐flux model was solved numerically. The experimental values were compared with the theoretical predictions. Good agreement was obtained with a maximum deviation about 10%. Finally, the two‐flux model described the radiation intensity distribution and local volumetric rate of energy absorption in the flat‐plate reactor packed with TGC. © 2002 Society of Chemical Industry     

基于导向滤波的分频高精度相干断层自动提取技术及应用

在诸多断裂刻画的案例中,往往是利用相干体对断裂进行刻画与描述,但是相干体在一定程度上对断裂的识别不够精细准确。因此本文提出了基于导向滤波的分频相干体的断层自动提取技术(Auto Fault Extraction, AFE),并针对特定工区改进了断裂识别的技术流程。首先在原始地震记录的基础上使用频谱分解技术生成多个分频数据体,再对分频数据体进行构造导向滤波,之后采用高精度相干算法对每个分频数据体求取相应的分频相干体,通过对比不同分频相干体选择出刻画工区内断裂带的优势频段,并使用带通滤波技术进行切除,最后在带通滤波的数据体上再次计算相干体数据,并在该相干体数据上做AFE属性提取。应用此技术在实际地震资料断裂刻画中,与常规相干体技术相比,对断裂带的刻画更加精细准确,与地质认识以及实际钻井勘探结果吻合度更高。     

两种不同脉冲欺骗攻击下随机多智能体系统的均方拟一致性

考虑实际应用中多智能体系统所处环境的复杂性及相关通信网络的开放性,主要研究了一类随机多智能体系统在受到两种不同脉冲欺骗攻击情况下实现均方拟一致性问题.所考虑的两种脉冲欺骗攻击包括替代攻击和虚假数据注入攻击,而攻击发生的概率则是通过引入服从伯努利分布的随机变量加以描述.结合随机过程相关知识和李雅普诺夫稳定性理论,给出系统...     

Different Effects of Androgen on the Expression of Fut1, Fut2, Fut4 and Fut9 in Male Mouse Reproductive Tract

The α-(1,2) fucosyltransferases (Fut1 and Fut2) and α-(1,3) fucosyltransferases (Fut4, Fut9) are responsible for the synthesis of Lewis X (LeX) and Lewis Y (LeY) conjugated to glycoproteins. We recently reported that these fucosyltransferases were differentially expressed in the reproductive tract of male mouse. Here, we studied the effect of androgen on fucosyltransferase expression through the use of mouse castration models. We found that Fut1 mRNA and Fut4 mRNA were upregulated, while Fut2 mRNA and Fut9 mRNA were downregulated by androgen in the caput epididymis. However, in the vas deferens and prostate, only Fut4 mRNA and Fut2 mRNA were respectively upregulated following exposure to androgen. In the seminal vesicle, all fucosyltransferases, with the exception of Fut9, were upregulated. We identified the androgen receptor binding sites (ARBSs) of Fut2, Fut4 and Fut9 in the caput epididymis. Luciferase assay for these ARBSs is able to provide an indication as to why Fut4 and Fut9 are differently expressed and regulated by androgen, although they catalyze the same α-(1,3) fucose linkage. Our study showed that androgen could differentially regulate the expression of these fucosyltransferases and provided an insight into the characteristic distribution of each fucosyltransferase responsible for LeX/LeY biosynthesis in the male reproductive tract.     

Preparation and self-assembly of a dual-functional copolymer for cancer therapy

The pH-responsive amphiphilic copolymer poly(SDMA-co-OEGMA) (PSO) was prepared from the pH-sensitive hydrophobic monomer 2-styryl-1,3-dioxan-5-yl methacrylate (SDMA) and the hydrophilic monomer oligo(ethylene glycol) methyl ether methacrylate (OEGMA) by radical polymerization. Polymeric aggregates with about 130 nm diameter were obtained by the self-assembly of PSO in neutral aqueous solution. The critical aggregation concentration of the copolymer was determined to be 6.5 mg/L (1.2 × 10^?7 M). Cinnamic aldehyde (CA) small molecules are broken away from PSO side chains after the hydrolysis of acid-labile cyclic acetal in cultured A375 human melanoma cells and further suppress the proliferation of this kind of tumor cells. Furthermore, the PSO aggregate was demonstrated to be a drug carrier for encapsulating Nile Red as model drug in in vitro testing. Based on the pH-responsive characteristic, the Nile Red molecules loaded in self-assembly process could be released from the aggregate inside cultured B16 mouse melanoma cells.     

Magnetic-separable robust microbeads using a branched polymer for stable enzyme immobilization

Uniform magnetic separable robust microbeads using a branched polymer were successfully developed for stable enzyme immobilization. The changed morphology of the microbeads was shown by scanning electron microscopy (SEM) analysis. The aldehyde groups on the polymers and imine groups derived from the Schiff base reaction between the aldehyde and amine moiety were found as the evidence of these reactions based on Fourier transform infrared (FT-IR) spectroscopy. The amine groups of the enzyme react with the aldehyde groups on the glutaraldehyde polymer so that the stable conjugations are formed. The specific activity of the conjugated enzyme was found to be retained more than 50%, but the reaction rate constant, K_m value was not changed, compared to the free enzyme. In addition, the enzyme conjugated in the microbeads was found to be highly stable for more than 50 days, pertaining over 60% of its initial activity, even after being reused more than 15 times repeatedly. Furthermore, the magnetic-driven controllability provided facile separable characters for the repeated recycling. It is expected that these microbeads can be utilized as a key tool for successful realization not only in enzymatic conversion processes but also in extended fields; bio-based sensors or analytical devices, bioprocessing, bioremediation, to name only a few of numerous areas.