Extending the response spectrum of organic photodetectors by quaternary active layer method with complementary absorption spectra

In this work, we report a new method for extending the response spectra of organic photodetectors (OPDs) by incorporating PBDT-TT-C and PBDT-TT-F in the P3HT:PC₆₁BM. The effects of PBDT-TT-C and PBDT-TT-F incorporation on the optical and electrical properties of OPDs were investigated, It was found that when the mass ratio of P3HT:PBDT-TT-F:PBDT-TT-C:PC₆₁BM was 12:2:2:8, the response spectrum of the active layer was extended to 780 nm. The responsivity (R) and external quantum efficiency (EQE) of the OPDs reached 340, 376, 315 mA/W and 67%, 88%, 85% under 630, 530, and 460 nm illumination and −1 V bias, respectively, and the detectivity (D*) reached 10¹² Jones. The results show that the inclusion of an appropriate amount of donor material with similar chemical structure and complementary absorption spectrum can reduce the influence of the doping material on the micro-morphology of the original film while improving the absorption of the spectrum. The interaction between the donor materials promotes the generation of photogenerated carriers and increases the photocurrent of the OPDs. In addition, the incorporation of the different component promotes crystallization of the film, resulting in a reduction in dark current of the OPDs.     

显微拉曼光谱技术对射击残留物的有机颗粒研究

为射击残留物检测提供了一个快速、简便、准确的无损检测方法,通过激光显微拉曼光谱技术对弹药中的发射药及射击残留物中的有机颗粒进行了研究。研究发现,检测射击残留物有机颗粒获得最优拉曼信号的激发波长为473nm,可有效避开荧光干扰。射击残留物有机颗粒主要来自部分燃烧的发射药颗粒,拉曼光谱证明其主要成分与发射药主要成分基本一致,但部分拉曼谱峰强度降低、消失或是线宽变宽,证明其物质结构也在一定程度上受到了破坏。通过微观形态观察,射击残留物有机颗粒表面以铜黄色、灰黑色为主,表面分布熔坑及附着带有金属光泽的球形无机颗粒,这些特有形貌可视为射击残留物的典型特征,成为射击残留物的重要判据。     

Facile synthesis and characterization of novel pseudo-hypercrosslinked resin

A kind of pseudo-hypercrosslinked polymer resin was firstly synthesized via a continuous Friedel-Crafts alkylation poly- merization of benzene, diphenyl and their dichloromethyl derivatives. And the micromorphology and adsorption properties of these resins were investigated. The results demonstrated that the novel resins have high-specific surface area （581.26-974.88 m^2/g）, high- pore volume （0.56-1.65 mL/g）, small average porous radius （1.93-3.67 nm） and excellent adsorption properties for small non-polar organic molecules.     

黄河三角洲土体非均匀性及对底坡微地貌形成影响

通过在潮滩现场 2 0m× 2 0m范围对土体细致的微贯试验和所取样品室内土体粒度分析, 指出黄河三角洲土体的物理及工程力学性质在小尺度空间上具有非均匀性, 这种非均匀性对黄河口底坡微地貌形成会产生控制性的影响作用。     

Are the evidences of forensic entomology preserved in ethanol suitable for SEM studies?

In forensic practice, the use of arthropod evidences to estimate the postmortem interval is a very good approach when the elapsed time from death is long, but it requires the correct identification of the specimens. This is a crucial step, not always easy to achieve, in particular when dealing with immature specimens. In this case, scanning electronic microscopy (SEM) can be useful, but the techniques used to preserve specimens in forensic practice are usually different from those used to prepare specimens for SEM studies. To determine whether forensic evidences preserving techniques are also compatible with SEM analysis, we have compared specimens of all the immature stages of Calliphora vicina Robineau-Desvoidy, 1830 (Diptera, Calliphoridae) preserved in 70% ethanol, with others prepared with aldehydic fixative techniques that are more appropriate for SEM studies. At the same time, two drying techniques have also been compared with both fixative techniques, the critical point drying and air-drying following with hexamethyldisilizane treatment (HMDS). Our results indicate that there are not basis against recommending the use of ethanol to preserve forensic entomological evidences and that both drying methods appear to offer good results for second and third instar larvae, although HMDS behaves better with eggs and pupae.     

室温交联型硅丙微胶乳的合成研究II.改性微胶乳的粒径控制及其微观形态表征

采用种子微乳液聚合法和单体预乳化法分别合成了室温交联型有机硅改性聚丙烯酸酯微胶乳,研究了硅烷单体的添加和氨化反应对改性微胶乳粒子大小及分布的影响。结果表明:采用种子微乳液聚合法得到的硅丙微胶乳粒子大小与硅烷单体的种类、用量和添加顺序无关,平均粒径约为40~60nm。TEM照片显示出,采用种子微乳液聚合法合成的硅丙微胶乳粒子由于内部存在交联结构而导致表面形状不规则,有“乳突”现象;而采用预乳化法合成的硅丙微胶乳粒径粗大,呈规则的球形,氨化后粒径从100nm以上减小到80nm左右,粒子表面出现“绒毛”现象,这是由于硅烷组分的水解反应受到抑制而使粒子内部的交联密度降低的缘故。