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71.
Properties of the angular gap in a one-dimensional photonic band gap structure containing single negative materials are investigated. This gap forms at oblique incidence due to the total internal reflection into air when the Snell's law breaks down. Its lower edge occurs at the frequency where the refractive index of one or both layers of the structure approaches zero. This gap is found to be highly sensitive to the incident angle and the polarization of the incident light, but is not affected by the thickness ratio of the layers. It is also shown that the electric field gets extremely enhanced at the lower edge of this gap for transverse magnetic polarization. This highly enhanced electric field can be utilized for certain applications. 相似文献
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74.
Abdullah M. Asiri Tariq R. Sobahi Mona Mohammad Al-Amari Mohammad Asad Mohie E. M. Zayed Salman A. Khan 《Journal of solution chemistry》2018,47(11):1711-1724
4-[(2-Hydroxy-naphthalen-1-ylmethylene)-amino]-1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazol-3-one (HDDP) was synthesized by the reaction of 4-amino-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one with 2-hydroxy-l-naphthaldehyde. The structure was confirmed by the IR, 1H-NMR, 13C-NMR, and EI-MS spectra and elemental analysis. Physicochemical parameters of the HDDP such as extinction coefficient, oscillator strength, transition dipole moment, Stokes shift, and fluorescence quantum yield in different solvents were studied on the basis of polarities. The interactions of various metal ions with HDDP were also studied using steady state fluorescence measurements. The emission profile reveals that it acts as off–on type fluorescent chemosensor for selective and sensitive detection of Al3+ ions. Complexation stoichiometry and mechanism of enhancement were determined from a Benesi–Hildebrand plot. 相似文献
75.
Bartoli S Mahmood T Malik A Dixon S Kilburn JD 《Organic & biomolecular chemistry》2008,6(13):2340-2345
A chiral bisguanidinium macrocycle binds N-Boc-L-glutamate in a 1 : 1 stoichiometry with significant selectivity in competitive solvent (DMSO-H(2)O). 相似文献
76.
Muhammad Saeed Aswa Firdous Muhammad Saleh Zaman Fatima Izhar Mubeshar Riaz Sabah Haider Muzamil Majeed Shahzaib Tariq 《中国化学会会志》2023,70(4):789-824
Nowadays, desulfurization of fuel oil has raised concern globally because of strict industrial and environmental legislations. Albeit hydrodesulfurization (HDS) has been extensively used in oil refineries to produce low sulfur oil (< 10 ppm) but not been proven as effective method for the removal of dibenzothiophene (DBT), benzothiophene (TH) and their derivatives. Subsequently, adsorptive desulfurization (ADS) and oxidative desulfurization (ODS) methods have been developed to achieve high removal efficiency. In the past decade, metal–organic frameworks (MOFs) and its composites as oxidative catalysts, as well as adsorbents, have attracted the researchers owing to high surface area, tunable properties, and reusable. The present review comprises use of MOFs and their composites for the removal of sulfur from fuel oil via ODS and ADS processes. Additionally, physicochemical properties of MOFs, mechanism, pros and cons of both process, regeneration, and future challenges have been discussed briefly. Moreover, current limitations and future prospective are also discussed. 相似文献
77.
Seyyed Hossein Miraghaie Ashkan Zandi Zahra Davari Mohamad Sadegh Mousavi-kiasary Zohre Saghafi Ali Gilani Yasin Kordehlachin Fatemeh Shojaeian Amir Mamdouh Zahra Heydari Farid Abedin Dorkoosh Babak Kaffashi Mohammad Abdolahad 《Macromolecular bioscience》2023,23(9):2300181
Pure positive electrostatic charges (PPECs) show suppressive effect on the proliferation and metabolism of invasive cancer cells without affecting normal tissues. PPECs are used for the delivery of drug-loaded polymeric nanoparticles (DLNs) capped with negatively charged poly(lactide-co-glycolide) (PLGA) and Poly(vinyl-alcohol) PVA into the tumor site of mouse models. The charged patch is installed on top of the skin in the mouse models' tumor region, and the controlled selective release of the drug is assayed by biochemical, radiological, and histological experiments on both tumorized models and normal rats' livers. It is found that DLNs synthesized by PLGA show great attraction to PPECs due to their stable negative charges, which would not degrade immediately in blood. The burst and drug release after less than 48h of this synthesized DLNs are 10% and 50%, respectively. These compounds can deliver the loaded-drug into the tumor site with the assistance of PPECs, and the targeted-retarded release will take place. Hence, local therapy can be achieved with much lower drug concentration (conventional chemotherapy [2 mg kg−1] versus DLNs-based chemotherapy [0.75 mg kg−1]) with negligible side effects in non-targeted organs. PPECs have many potential clinical applications for advanced-targeted chemotherapy with the lowest discernible side effects. 相似文献
78.
A Photoferroelectric Perovskite‐Type Organometallic Halide with Exceptional Anisotropy of Bulk Photovoltaic Effects
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Dr. Zhihua Sun Dr. Xitao Liu Tariq Khan Chengmin Ji Muhammad Adnan Asghar Dr. Sangen Zhao Dr. Lina Li Prof. Maochun Hong Prof. Junhua Luo 《Angewandte Chemie (International ed. in English)》2016,55(22):6545-6550
Perovskite‐type ferroelectrics composed of organometallic halides are emerging as a promising alternative to conventional photovoltaic devices because of their unique photovoltaic effects (PVEs). A new layered perovskite‐type photoferroelectric, bis(cyclohexylaminium) tetrabromo lead ( 1 ), is presented. The material exhibits an exceptional anisotropy of bulk PVEs. Upon photoexcitation, superior photovoltaic behaviors are created along its inorganic layers, which are composed of corner‐sharing PbBr6 octahedra. Semiconducting activity with remarkable photoconductivity is achieved in the vertical direction, showing sizeable on/off current ratios (>104), which compete with the most active photovoltaic material CH3NH3PbI3. In 1 the temperature‐dependence of photovoltage coincides fairly well with that of polarization, confirming the dominant role of ferroelectricity in such highly anisotropic PVEs. This finding sheds light on bulk PVEs in ferroelectric materials, and promotes their application in optoelectronic devices. 相似文献
79.
Two new unbridged zirconocenes, bis(2,4,7-trimethyl indenyl)zirconium dichloride (Met-Ⅰ) andbis(2-methyl-4,7-diethyl indenyl)zirconium dichloride (Met-Ⅱ) were prepared in order to investigate thesteric effects of substituents on the nature of the catalysts for the polymerization of propylene. A mixture ofmethyl aluminoxane (MAO) and triisobutylaluminum [Al(iBu)_3] was used as cocatalyst to activate thesecatalysts. The decrease in steric bulkiness of substituents at 4 and 7 positions of the indenyl ring resulted inan increase of both activity and molecular weight as well as the isotacticity. 相似文献
80.
Bahri Sahin Huseyin Yilmaz Yasin Ust Ali Fuat Guneri Bahadır Gulsun 《European Journal of Operational Research》2009
One of the important parameters in the determination of optimal transportation system is economy. Therefore, a realistic method based on the technical, economical and operational parameters of various transportation modes, namely, road, railway, and sea routes is required in the analysis of costs. This method will take into consideration the probable price escalations during the lifetime of a certain transportation system. The cost of a unit of cargo or passenger per route length should be considered since it is an indicator of economics. In this paper, an approach for transportation cost analysis based on the economic analysis of the alternative modes of cargo or passenger transportation, is presented. 相似文献