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21.
Yonghui Liu Huaying Gao Xiaoli Sheng Yuming Zhou Beibei Wang Xiao Sha Maolu Jin Jie Zhao Wenqi Liu 《应用有机金属化学》2019,33(11)
In this work, a series of novel acidic polymerized ionic liquids were used as heterogeneous catalyst for alkylation of o‐Xylene with styrene. And the effect of the amount of initiator and the type of acid used for ion exchange on catalyst structure and the catalytic performance of catalysts for alkylation were studied thoroughly. The experiment results show: when the percentage of the amount of initiator in the total material is 3%, the polymerized ionic liquid catalyst MPM‐SO3H‐[C3V][SO3CF3] has the most uniform with a specific surface area of 97.30 m2/g and a pore volume of 0.35 cm3/g. Benefiting from the unique structure features, MPM‐SO3H‐[C3V][SO3CF3] manifested an excellent catalytic performance for alkylation of o‐Xylene with styrene, along with the conversion of styrene was 96.8% and the yield of 1‐Phenyl‐1‐ortho‐xylene ethane was 94.7%. Therefore, this work provides a novel reference to the synthesis of polymerized ionic liquids and clearly explains the advantage of novel acidic polymerized ionic liquids on alkylation. 相似文献
22.
《Current Applied Physics》2020,20(2):337-343
Radiotherapy for cancer patients requires accurate measurement of the absorbed dose of radiation in a treatment planning step. Various types of radiation detectors are currently utilized for dose measurement. Among them, calorimeters are known to be the most precise detector for measuring absorbed dose, but their on-site application is limited by the large size of the equipment. We developed a miniaturized chip calorimeter for application as a radiation detector. The calorimetric radiation detector was built using micro/nano fabrication techniques, and consists of an SU-8 photoresist absorber and high-sensitivity vanadium oxide (VOx) thermistors. The thermistors had a temperature resolution of 135 μK, and the calorimeter showed a thermal conductance of 11 μW/K. The detector was irradiated with various X-ray dose rates from a linear accelerator, and the absorbed dose to SU-8 was measured. The detector responses showed high linearity with dose rates, demonstrating the feasibility of the radiation detector for practical uses. 相似文献
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铌酸锂晶体具有非线性效应、电光效应、声光效应、光折变效应、压电效应与热释电效应等多种物理特性,在表面声波器件、光电器件、声光器件等方面获得广泛的应用。经历了六十多年的发展,铌酸锂晶体历久弥新,随着材料特性的不断开发,新功能、新器件、新应用层出不穷,尤其是铌酸锂单晶薄膜在薄膜滤波器、集成光电器件等领域的性能具有明显优势,被称为新一代信息和通信技术的关键材料。应用器件的发展正迫切要求基质晶体材料的发展,本文通过简述近年来铌酸锂的新发现、新应用,相应地探讨了铌酸锂晶体未来发展方向。 相似文献
26.
In this study, a new filter algorithm is presented for solving the nonlinear semidefinite programming. This algorithm is inspired by the classical sequential quadratic programming method. Unlike the traditional filter methods, the sufficient descent is ensured by changing the step size instead of the trust region radius. Under some suitable conditions, the global convergence is obtained. In the end, some numerical experiments are given to show that the algorithm is effective. 相似文献
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Researchers in actuarial sciences have investigated the tail behavior of the LCR and ECOMOR reinsurance treaties separately for managing extreme risks in reinsurance business. In practice, a reinsurance company may possess these two treaties simultaneously. Therefore, investigating the joint tail behavior of these two treaties is practically useful in risk management. This paper derives the asymptotic limit of the joint tail of these two reinsurance treaties under the setup of Jiang and Tang (2008). 相似文献
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The sonochemical synthesis of gold nanoparticles (GNPs) with different shapes and size distributions by using high‐intensity focused ultrasound (HIFU) operating at 463 kHz is reported. GNP formation proceeds through the reduction of Au3+ to Au0 by radicals generated by acoustic cavitation. TEM images reveal that GNPs show irregular shapes at 30 W, are primarily icosahedral at 50 W and form a significant amount of nanorods at 70 W. The size of GNPs decreases with increasing acoustic power with a narrower size distribution. Sonochemiluminescence images help in the understanding of the effect of HIFU in controlling the size and shapes of GNPs. The number of radicals that form and the mechanical forces that are generated control the shape and size of the GNPs. UV/Vis spectra and TEM images are used to propose a possible mechanism for the observed effects. The results presented demonstrate, for the first time, that the HIFU system can be used to synthesise size‐ and shape‐controlled metal nanoparticles. 相似文献
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Dr. Arik Kar Sumanta Sain Dr. Simanta Kundu Arka Bhattacharyya Dr. Swapan Kumar Pradhan Prof. Amitava Patra 《Chemphyschem》2015,16(5):1017-1025
Tuning the functional properties of nanocrystals is an important issue in nanoscience. Here, we are able to tune the photocatalytic properties of SnO2 nanocrystals by controlling their size and shape. A structural analysis was carried out by using X‐ray diffraction (XRD)/Rietveld and transmission electron microscopy (TEM). The results reveal that the number of oxygen‐related defects varies upon changing the size and shape of the nanocrystals, which eventually influences their photocatalytic properties. Time‐resolved spectroscopic studies of the carrier relaxation dynamics of the SnO2 nanocrystals further confirm that the electron–hole recombination process is controlled by oxygen/defect states, which can be tuned by changing the shape and size of the materials. The degradation of dyes (90 %) in the presence of SnO2 nanoparticles under UV light is comparable to that (88 %) in the presence of standard TiO2 Degussa P‐25 (P25) powders. The photocatalytic activity of the nanoparticles is significantly higher than those of nanorods and nanospheres because the effective charge separation in the SnO2 nanoparticles is controlled by defect states leading to enhanced photocatalytic properties. The size‐ and shape‐dependent photocatalytic properties of SnO2 nanocrystals make these materials interesting candidates for photocatalytic applications. 相似文献