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991.
A nucleophilic substitution reaction of an α‐ferrocenyl alcohol with various amines, indoles and thiols was successfully developed by using a catalytic amount of Bi(NO3)3.5H2O at room temperature without the aid of phase transfer catalyst. The reactions proceeded in aqueous media, leading to the formation of new C=C, C=N and C=S bonds bearing ferrocenyl substituent with high efficiency. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
992.
Xiao Wang Xinhua Song Minfeng Jiang Pin Li Yang Hu Kai Wang Huixia Liu 《Optics & Laser Technology》2012,44(3):656-663
Laser joining parameters play a very significant role in determining the quality of laser transmission joining between PET films and 316L stainless steel plates. In the present work, Laser power, joining speed and stand-off-distance were considered as joining parameters. The parameters that influence the quality of laser transmission joining were optimized using response methodology for achieving good joint strength and minimal joint width. The central composite second-order Rotational Design (CCRD) has been utilized to plan the experiments and response surface methodology (RSM) is employed to develop mathematical relationships between joining parameters and desired responses. Based on the developed mathematical models, the interaction effects of the process parameters on laser transmission joining were investigated and optimum joining parameters were achieved. The experimental values nearly agree with the predicted values from mathematical models, indicates that the models can predict the responses adequately and optimize the key process parameters quickly. 相似文献
993.
Lijie Zhu Minghan Zhang Xiuying Liu He Liu Yutang He Bo Wang Tao Ma 《Chemical Papers》2017,71(3):653-660
Soyasaponins were shown to have a wide range of biological activities in previous studies; however, the activities of their monomeric compounds are unclear. The aim of this study was to evaluate the in vitro antioxidant activities of soyasaponins in HepG2 cells. Four soyasaponins were isolated from soy hypocotyls and identified as soyasaponin Aa, Ab, Ba, and Bb. The protective effects of these soyasaponins against production of hydrogen peroxide-induced reactive oxygen species in cells were investigated. The cellular antioxidant activity of soyasaponins was found to be in a dose-dependent manner at concentrations ranging between 25 and 400 μg/mL in 24 h. Finally, based on cell morphology observations, group A soyasaponins showed better cellular antioxidant activity and anti-oxidative enzyme activity than group B ones, with an optimal concentration of 100 μg/mL. 相似文献
994.
995.
Effect of Polymerizable Photoinitiators on the UV‐polymerization behaviors of photosensitive polysiloxane
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Bo Jiang Tong Zhang Liwei Zhao Zhiming Xu Yudong Huang 《Journal of polymer science. Part A, Polymer chemistry》2017,55(10):1696-1705
In this contribution, three polymerizable benzophenone photoinitiators containing maleimide group including 4‐maleimidebenzophenone (MBP), 4‐chlorine‐4′‐maleimide benzophenone (CMBP), and 4‐maleimide‐4′‐[(4‐maleimide)thiophenyl]benzophenone (MMTBP) were designed and synthesized to enhance the polymerization degree of photosensitive polysiloxane containing methacryloxy active groups (MAPSO). The polymerization behaviors of the MAPSO cured by different photoinitiators were investigated using Fourier transform infrared (FTIR). It was noted that the MAPSO initiated by MMTBP showed a high carbon–carbon double bond conversion above 80% because of the existence of thiophenyl group which could generate more radicals from the photolysis reaction at the C? S bond. In addition, the thermal stability of the UV‐cured MAPSO were studied by thermogravimetric analysis (TGA), the result showed that the initial 5% mass loss (T 5%) and residual weight percent at 800 °C in nitrogen of the UV‐cured MAPSO initiated by MMTBP systems was 200 °C and 33.8%. Thus, this work provides a new perspective and efficient strategy to improve the polymerization degree of UV‐curable polysiloxanes with carbon–carbon double bonds. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 1696–1705 相似文献
996.
Immobilization of AIEgens into metal‐organic frameworks: Ligand design,emission behavior,and applications
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Bo Gui Na Yu Yi Meng Fang Hu Cheng Wang 《Journal of polymer science. Part A, Polymer chemistry》2017,55(11):1809-1817
Aggregation‐induced emission (AIE), in which the luminophores are highly emissive in aggregate state, is one of the most unique photophysical phenomena and has shown interesting applications in many areas. The immobilization of AIE luminogens (AIEgens) into metal‐organic frameworks (MOFs), which are inorganic‐organic hybrid porous materials with tunable and predictable structures, has been investigated over the past few years. These well‐defined porous frameworks cannot only provide an ideal platform for studying the mechanism of AIE phenomenon in solid state, but also show potential applications from sensing to white light‐emitting diodes. In this highlight, we will summarize the recent progress of AIEgens‐based MOFs, including ligand design, emission behavior, and applications. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 1809–1817 相似文献
997.
Herein we discovered that a Nile Red-based probe with a cinnamoyl unit was highly selective and sensitive to N2H4. Hydrazinolysis by N2H4 would release a hydroxyl substituted Nile Red and result in remarkable fluorescence quench. Importantly, Cys/Hcy would not interrupt the N2H4 recognition. This is because, for this probe, the combination of the π-π conjugate system can stabilize the ethylene union, which results in the nucleophilic addition of the thiol group of Cys/Hcy becomes non-effective. 相似文献
998.
999.
Jian-Cai Huang Hui Xiao Dr. Zhixin Chen Dr. Wenxu Zheng Dr. Chang-Cang Huang Dr. Shu-Ting Wu Zenghong Xie Prof. Naifeng Zhuang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(56):14017-14024
Chiral compounds are known to be important not only because they are the fundamental components of living organisms, but also for their unique chiroptical properties. In recent years, scientists have fabricated several chiral organic supramolecular aggregates by using chiral physical fields, such as vortex flow. Herein, the relationship between dynamic chiroptical properties and rheological nature is discussed, suggesting the shear thinning properties of non-Newtonian fluids might help colloidal particles adopt a chiral arrangement in vortices. Furthermore, the storage modulus of colloids could be increased by adding a linking agent, which successfully kept the dynamic chiroptical properties in the static state. Moreover, the salt effect on the host–guest interaction involved in the colloids was studied, the results suggested a significant enhancement of the transferred dynamic circular dichroism for the achiral guest molecule. 相似文献
1000.
介绍线型光束可燃气体探测器的的校准方法。对线型光束可燃气体探测器的示值误差、报警功能、响应时间、光强衰减性能和抗日光干扰性能等主要计量特性及技术指标进行校准,给出了各主要计量特性的校准条件、试验设备和具体校准方法。对两台线型光束可燃气体探测器进行了校准,其示值误差用相对误差表示分别为–5%和4%,用引用误差表示分别为–4%FS和3%FS。经验证,上述结果均未超出设定指标,响应时间等其它主要计量特性也符合方法要求。该方法校准后的计量特性及技术指标较为合理,校准方法切实可行,可以用于线型光束可燃气体探测器的校准。 相似文献