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171.
过渡金属氧化物(MO)可以显著影响聚磷酸铵(APP)的热分解过程,进而改善APP复配膨胀阻燃聚合物材料的阻燃效率。将ZnO、Fe2O3、TiO2掺入到APP中,采用热失重分析(TGA)、X射线光电子能谱(XPS)和X射线衍射分析(XRD),考察了3种MO对APP热分解行为的影响,分析了相互作用过程中金属原子和磷原子化学结合状态的变化以及高温热分解产物的物相结构。TGA和XPS图谱分析结果表明,MO可降低APP的起始热分解温度,并催化APP释放NH3和H2O,而在热分解后期由于金属磷酸盐的形成可显著增加APP的高温残留量。3种MO催化APP热分解脱NH3和H2O的活性由大到小的顺序是:ZnO>Fe2O3>TiO2,而对APP凝聚相热分解P-O产物的交联能力从大到小的顺序为:Fe2O3>ZnO>TiO2。XRD结果显示,ZnO在高温下与APP反应生成了Zn(PO3)2晶体,而Fe2O3和TiO2与APP反应分别生成了Fe4(P2O7)3和TiP2O7晶体。 相似文献
172.
为实现对循环水水质的远程监测,设计并开发了一种基于嵌入式技术的热力站远程水质监测系统的监测终端。监测终端由水质传感器、GPRS模块、通信转换模块及嵌入式开发板组成。嵌入式开发板以ARM11系列的Tiny6410为硬件基础,并嵌入WinCE系统作为软件平台,同时加入SQLite数据库以实现将水质传感器采集到的氯离子、PH值、溶解氧等参数的本地存储、查询及图表显示。最后监测终端通过GPRS模块与数据中心建立无线连接,接收数据中心的配置命令,并将现场测得数据发送到远端数据中心。调试结果表明:远程监测终端实现了循环水水质远程监测的功能要求,对于实现水质自动化监测具有一定的理论意义和实用价值。 相似文献
173.
Pseudo almost periodic dynamics of delay Nicholson's blowflies model with a linear harvesting term 下载免费PDF全文
In this paper, we investigate a class of delay Nicholson's blowflies model with a linear harvesting term, new criteria for the existence and convergence dynamics of positive pseudo almost periodic solutions are established by using the fixed point method and the properties of pseudo almost periodic function, together with constructing suitable Lyapunov functionals. The obtained results extend previously known results, and they also partially answer an open problem proposed by L. Berezansky et al. Finally, an example with simulation is presented to demonstrate the effectiveness of theoretical results. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
174.
An asymmetric 1,6-addition of diphenylphosphine to (4-aryl-1,3-butadienylidene)bis(phosphonates) catalyzed by a PCP pincer–Pd complex has been developed for the synthesis of chiral allylic phosphines with up to 91% ee under mild conditions. 相似文献
175.
Long Tang Liang Bai Yaping Duan Wei Xia Wenwen Dong Dongsheng Li 《无机化学与普通化学杂志》2014,640(11):2268-2273
Three ZnII and CdII complexes with Y‐shaped dicarboxylate ligands, namely [Zn(L1)(2,2′‐bpy)2(H2O)] · 2H2O ( 1 ), [Zn(L1)(bpp)(H2O)] ( 2 ), and [Cd(L1)(H2O)] · H2O ( 3 ) [H2L1 = N‐phenyliminodiacetic acid, 2,2′‐bpy = 2,2′‐bipyridine, bpp = 1,3‐bis(4‐pyridyl)propane] were synthesized and characterized by elemental analysis, IR spectroscopy single‐crystal X‐ray diffraction, and thermogravimetric analyses. Compound 1 shows an hydrogen‐bonded 2D network, whereas compound 2 is an infinite 1D wavy chain structure, though O–H ··· O hydrogen‐bonded to form a 2D network. Compound 3 displays a 2D uninodal 3‐connected Shubnikov plane net with the point symbol of (4.82). Moreover, the solid‐state such as thermal stabilities and fluorescence properties of 1 – 3 were also investigated. 相似文献
176.
177.
Development of a solid‐phase microextraction fiber by the chemical binding of graphene oxide on a silver‐coated stainless‐steel wire with an ionic liquid as the crosslinking agent 下载免费PDF全文
Min Sun Juanjuan Feng Yanan Bu Huimin Duan Xiaojiao Wang Chuannan Luo 《Journal of separation science》2014,37(24):3691-3698
Graphene oxide was bonded onto a silver‐coated stainless‐steel wire using an ionic liquid as the crosslinking agent by a layer‐by‐layer strategy. The novel solid‐phase microextraction fiber was characterized by scanning electron microscopy, energy‐dispersive X‐ray spectroscopy and Raman microscopy. A multilayer graphene oxide layer was closely coated onto the supporting substrate. The thickness of the coating was about 4 μm. Coupled with gas chromatography, the fiber was evaluated using five polycyclic aromatic hydrocarbons (fluorene, anthracene, fluoranthene, 1,2‐benzophenanthrene, and benzo(a)pyrene) as model analytes in direct‐immersion mode. The main conditions (extraction time, extraction temperature, ionic strength, and desorption time) were optimized by a factor‐by‐factor optimization. The as‐established method exhibited a wide linearity range (0.5–200 μg/L) and low limits of determination (0.05–0.10 μg/L). It was applied to analyze environmental water samples of rain and river water. Three kinds of the model analytes were quantified and the recoveries of samples spiked at 10 μg/L were in the range of 92.3–120 and 93.8–115%, respectively. The obtained results indicated the fiber was efficient for solid‐phase microextraction analysis. 相似文献
178.
Synthesis and Characterization of Aminoporphyrin‐End‐Functionalized Poly(N‐isopropylacrylamide) with Photodynamic and Thermoresponsive Effects 下载免费PDF全文
Yang Yang Yanhui Li Nannan Qiu Guihua Cui Prof. Toshifumi Satoh Prof. Qian Duan 《化学:亚洲杂志》2014,9(5):1379-1387
The novel aminoporphyrin‐end‐functionalized poly(N‐isopropylacrylamide) (PNIPAM) polymer H2N‐TPP‐PNIPAM (TPP=5,10,15,20‐tetraphenyl‐21H,23H‐porphyrin) behaves as a multifunctional platform that displays a photodynamic effect, thermosensitivity, and fluorescence properties. The polymer was designed by using an asymmetrical aminoporphyrin (i.e., H2N‐TPP‐Cl) as the initiator for the atom‐transfer radical polymerization of N‐isopropylacrylamide (NIPAM). The polydispersity index (PDI) obtained by gel‐permeation chromatography indicated that the molecular‐weight distribution was narrow (1.09<PDI<1.27). The lower critical solution temperatures of H2N‐TPP‐PNIPAM showed a decreasing trend as the molecular weight was increased as a result of the incorporation of the porphyrin group at the end of the chain. The fluorescence spectra revealed the luminescent properties of the materials. The results of confocal laser scanning microscopy showed that the polymer could enter the cytoplasm through endocytosis. In addition, the multifunctional platform exhibited low toxicity against normal cells (L929) and cancer cells (Hela) and enhanced photodynamic activity towards HeLa cells, without significant necrocytosis towards L929 cells; as a result this material may be useful in the future for practical photodynamic therapy. 相似文献
179.
Haodi Wang Li Zhang Binyuan Liu Bing Han Zhongyu Duan Cuiyun Qi Dae‐Won Park Il Kim 《Macromolecular rapid communications》2015,36(18):1646-1650
High molecular weight cyclic poly(ε‐caprolactone)s (cPCLs) with variable ring size are synthesized via light‐induced ring closure of α,ω‐anthracene‐terminated PCL (An‐PCL‐An). The ring size of cPCL is tunable simply by adjusting the polymer concentration from 10 to 100 mg mL−1 in THF. The cycloaddition via the bimolecular cyclization of An‐PC‐An is well characterized by a variety of analyses such as 1H NMR and UV–vis spectroscopies, gel‐permeation chromatography, and differential scanning calorimetry. The reversible dimerization of An induced by heating enables the cyclic PCL to have a switchable “on–off” capability. This novel light‐induced ring‐closure technique can be one of the most powerful candidates for producing various well‐defined cyclic polymers in highly concentrated polymer solution.
180.
Chia‐Wei Chu Xiaomin Zhai Chih Jie Lee Po‐Hao Wang Yubo Duan Din Ping Tsai Baile Zhang Yuan Luo 《Laser \u0026amp; Photonics Reviews》2015,9(4):399-404
Transformation optics, a recent geometrical design strategy of light manipulation with both ray trajectories and optical phase controlled simultaneously, promises an invisibility cloaking device that can render a macroscopic object invisible even to a scientific instrument measuring optical phase. Recent “carpet” cloaks have extended their cloaking capability to broadband frequency ranges and macroscopic scales, but they only demonstrated the recovery of ray trajectories after passing through the cloaks, while whether the optical phase would reveal their existence still remains unverified. In this paper, a phase‐preserved macroscopic visible‐light carpet cloak is demonstrated in a geometrical construction beyond two dimensions. As an extension of previous two‐dimensional (2D) macroscopic carpet cloaks, this almost‐three‐dimensional carpet cloak exhibits three‐dimensional (3D) invisibility for illumination near its center (i.e. with a limited field of view), and its ideal wide‐angle invisibility performance is preserved in multiple 2D planes intersecting in the 3D space. Optical path length is measured with a broadband pulsed‐laser interferometer, which provides unique experimental evidence on the geometrical nature of transformation optics.