排序方式: 共有19条查询结果,搜索用时 15 毫秒
1.
Xi Du Liaolin Zhang Guoping Dong Kaniyarakkal Sharafudeen Jian Wen Dongdan Chen Qi Qian Jianrong Qiu 《Journal of the American Ceramic Society》2014,97(1):185-188
ZnO–TeO2–P2O5 glasses were prepared by melt‐quenching method. The color of the glass samples changed from colorless to pale red and dark red with increasing TeO2 content. Coloration mechanism and nonlinear optical properties of ZnO–TeO2–P2O5 glasses have been investigated. Raman spectra and transmission electron microscope measurements indicated the precipitation of ZnTe quantum dots in the glasses and ZnTe quantum dots are the origin of coloration. Z‐scan technique was used to examine the nonlinear optical properties of the glasses. The glass sample with 30 mol% TeO2 exhibits large third‐order nonlinear optical susceptibility of 10?11 esu. 相似文献
2.
Employing the single beam Z-scan technique with nanosecond laser pulses at 532 nm, the refractive and absorptive nonlinearities of donor and acceptor substituted (2E)-1-(3,4-dimethoxyphenyl)-3-phenylprop-2-en-1-one have been studied. The sign of the nonlinear index of refraction (n 2) is found to be negative and the magnitude of n 2 is in the order of 10?11 esu. The second-order molecular hyperpolarizability (γh) is calculated to be in the order of 10?32 esu. The variation of nonlinear absorption coefficient (βeff) with input intensity (I 0) is studied and the nonlinear absorption mechanism is found to be reverse saturable absorption (RSA). The enhancement of nonlinearity due to the donor and acceptor substitution is in accordance with the variation in π electron delocalization in the molecules. The compounds exhibit good optical limiting as well. 相似文献
3.
Huiwang Lian Yang Li Kaniyarakkal Sharafudeen Weiren Zhao Gopi R. Krishnan Shaoan Zhang Jianrong Qiu Kai Huang Gang Han 《Advanced materials (Deerfield Beach, Fla.)》2020,32(28):2002495
By virtue of their narrow emission bands, near-unity quantum yield, and low fabrication cost, metal halide perovskites hold great promise in numerous aspects of optoelectronic applications, including solid-state lighting, lasing, and displays. Despite such promise, the poor temperature tolerance and suboptimal quantum yield of the existing metal halide perovskites in their solid state have severely limited their practical applications. Here, a straightforward heterogeneous interfacial method to develop superior thermotolerant and highly emissive solid-state metal halide perovskites is reported and their use as long-lasting high-temperature and high-input-power durable solid-state light-emitting diodes is illustrated. It is found that the resultant materials can well maintain their superior quantum efficiency after heating at a temperature over 150 °C for up to 22 h. A white light-emitting diode (w-LED) constructed from the metal halide perovskite solid exhibits superior temperature sustainable lifetime over 1100 h. The w-LED also displays a highly durable high-power-driving capability, and its working current can go up to 300 mA. It is believed that such highly thermotolerant metal halide perovskites will unleash the possibility of a wide variety of high-power and high-temperature solid-state lighting, lasing, and display devices that have been limited by existing methods. 相似文献
4.
Riyas Sharafudeen 《Color research and application》2019,44(1):44-49
Titanium dioxide (TiO2) manufacturing industries measure optical properties such as brightness, colour, tint strength, tint tone, gloss, scatter coefficient, and others to ensure the quality of the product. Product characterization and process control generally focus on the optical properties, which determine its quality. In this work, titania rutile pigment with varying tint strength and tint tone is analyzed and a correlation is established between particle size and the optical properties such as tint strength and tint tone. It is observed that optical properties of titania pigment depends on the particle size as well as particle size distribution. A relatively faster evaluation of tint strength and tint tone can be made using the reflectance and particle size measurements. Analytical samples were prepared by ultrasonic dispersion of pigment in water containing calgon as dispersing agent. To verify the accuracy of the method, pigment tint strength and tint tone obtained from this study are compared with those resulting from traditional analysis. The results showed that the new method is viable. 相似文献
5.
Petr Kovaricek Peter Nadazdy Eva Pluharova Alica Brunova Riyas Subair Karol Vegso Valentino Libero Pio Guerra Oleksandr Volochanskyi Martin Kalbac Alexander Krasnansky Pallavi Pandit Stephan Volker Roth Alexander Hinderhofer Eva Majkova Matej Jergel Jianjun Tian Frank Schreiber Peter Siffalovic 《Advanced functional materials》2021,31(13):2009007
2D hybrid organic–inorganic perovskites are valued in optoelectronic applications for their tunable bandgap and excellent moisture and irradiation stability. These properties stem from both the chemical composition and crystallinity of the layer formed. Defects in the lattice, impurities, and crystal grain boundaries generally introduce trap states and surface energy pinning, limiting the ultimate performance of the perovskite; hence, an in-depth understanding of the crystallization process is indispensable. Here, a kinetic and thermodynamic study of 2D perovskite layer crystallization on transparent conductive substrates are provided—fluorine-doped tin oxide and graphene. Due to markedly different surface structure and chemistry, the two substrates interact differently with the perovskite layer. A time-resolved grazing-incidence wide-angle X-ray scattering (GIWAXS) is used to monitor the crystallization on the two substrates. Molecular dynamics simulations are employed to explain the experimental data and to rationalize the perovskite layer formation. The findings assist substrate selection based on the required film morphology, revealing the structural dynamics during the crystallization process, thus helping to tackle the technological challenges of structure formation of 2D perovskites for optoelectronic devices. 相似文献
6.
K. Devan Abhitab Bachchan A. Riyas T. Sathiyasheela P. Mohanakrishnan S.C. Chetal 《Nuclear Engineering and Design》2011,241(8):3058-3067
Fast breeder reactors based on metal fuel are planned to be in operation for the year beyond 2025 to meet the growing energy demand in India. A road map is laid towards the development of technologies required for launching 1000 MWe commercial metal breeder reactors with closed fuel cycle. Construction of a test reactor with metallic fuel is also envisaged to provide full-scale testing of fuel sub-assemblies planned for a commercial power reactor. Physics design studies have been carried out to arrive at a core configuration for this experimental facility. The aim of this study is to find out minimum power of the core to meet the requirements of safety as well as full-scale demonstration. In addition, fuel sustainability is also a consideration in the design. Two types of metallic fuel pins, viz. a sodium bonded ternary (U-Pu-6% Zr) alloy and a mechanically bonded binary (U-Pu) alloy with 125 μm thickness zirconium liner, are considered for this study. Using the European fast reactor neutronics code system, ERANOS 2.1, four metallic fast reactor cores are optimized and estimated their important steady state parameters. The ABBN-93 system is also used for estimating the important safety parameters. Minimum achievable power from the converter metallic core is 220 MWt. A 320 MWt self-sustaining breeder metal core is recommended for the test facility. 相似文献
7.
Chenxing Liao Renping Cao Zhijun Ma Yang Li Guoping Dong Kaniyarakkal N. Sharafudeen Jianrong Qiu 《Journal of the American Ceramic Society》2013,96(11):3552-3556
In this article, we propose a facile method for synthesis of K2SiF6:Mn4+ phosphor and discuss its promising application in warm‐white light emitting diodes (LED). The K2SiF6:Mn4+ was synthesized from SiO2 powders through redox reaction in HF/KMnO4 solution. The optical properties of LEDs containing different ratios of K2SiF6:Mn4+ phosphor and commercial Ce3+‐doped garnets (YAG‐40) yellow–green phosphor were studied. A warm‐white LED, with color temperature of 3510 K and color rendering index of 90.9 and efficacy of 81.56 lm/W was demonstrated. 相似文献
8.
Riyas Sharafudeen Jihad Mohammed Al-Hashim Mohammed Olian Al-Harbi Ahmed Ibrahim Al-Ajwad Ali Abdulaziz Al-Waheed 《SILICON》2017,9(6):917-922
The present study reveals a cost benefit process in an open system for utilizing desert sand for preparing sodium silicate or precipitated silica. A simple alkali fusion method has been developed to prepare sodium silicate directly from sand and finally pure precipitated silica by acid precipitation. The reaction weight ratio of alkali to sand reaction parameters are studied for optimizing the silica yield. About 80% pure precipitated silica has been prepared in an open system at 150 °C within 45 min. Wet chemical methods, FTIR, TG-DTA, XRD and SEM techniques are used to characterize the silica prepared from sand available in Saudi Arabian deserts. In the XRD pattern, the peak corresponding to silica was obtained at the diffraction angle of 21.8 ° and it was found to be amorphous in nature. 相似文献
9.
For faster growth of nuclear power in India, it is essential to shift to the use of metal-fuels in fast breeder reactors (FBR), which gives a higher breeding ratio (BR) and lower doubling time (DT). Also, future commercialization of the FBR fuel cycle necessitates the use of metallic fuel along with the pyro-process recycling, which can be less costly than oxide fuel reprocessing. Two-dimensional diffusion calculations have been performed to investigate the various physics parameters of metal (U–Pu–Zr) fuelled FBR cores as a function of reactor parameters like reactor power, smear density, zirconium content in the fuel and the number of rows in radial blankets. A 1000 MWe fast reactor with U–Pu fuel (i.e. metal-fuel with no zirconium – which is a theoretical possibility now, due to the lack of irradiation experience) can attain a breeding ratio of 1.61 and a reactor fuel doubling time of 6.6 yrs. Two methods to reduce the sodium void reactivity, which is high and positive in metal-fuelled FBR cores, are suggested. 相似文献
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