HIERARCHY Hierarchy, originated from an ancient Greek word'εραρχα', is a property characterized by the arrangement of a set of individual items [1] that are placed 'above','below'or'a...
HIERARCHY Hierarchy, originated from an ancient Greek word'εραρχα', is a property characterized by the arrangement of a set of individual items [1] that are placed 'above','below'or'at the same level as' one another in different *** items can be physical matter such as atoms, molecules, particles, objects, etc., or can be abstract and intangible entities such as names, values, categories, ***, although we are not consciously aware of its existence, is an essential concept in a wide variety of fields, such as life science, materials science, computer science, philosophy, mathematics, physics,chemistry, biology, geography, topography, organizational theory, systems theory, architecture, urban construction, industrial processes and the social sciences.
On the basis of experiments, the ZrO2 grain boundaries are classified into three types: the ''clean'' grain boundaries, the grain boundaries with amorphous phases and the grain boundaries with crystal ...
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On the basis of experiments, the ZrO2 grain boundaries are classified into three types: the ''clean'' grain boundaries, the grain boundaries with amorphous phases and the grain boundaries with crystal phases. The structure and property of the three types of grain boundaries were analyzed from the aspects of microstructure and lattice defects, and the conductivity of the crystal grain boundary phases was calculated with the effective-medium theory to be as three times higher as that of the matrix, an idea of further enhancing the ionic conduction of ZrO2 by modifying grain boundaries was thus proposed. The effect of the ZrO2 grain boundaries on the EMF of the oxygen sensor was discussed with simplified models.
Ti3SiC2/TiB2 composite was successfully obtained by hot pressing Ti/TiC/Si/B4C power *** fraction of TiB2 in Ti3SiC2/TiB2 composite can not exceed 10%.Incorporation of excessive TiB2 will affect the reactions *** and ...
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Ti3SiC2/TiB2 composite was successfully obtained by hot pressing Ti/TiC/Si/B4C power *** fraction of TiB2 in Ti3SiC2/TiB2 composite can not exceed 10%.Incorporation of excessive TiB2 will affect the reactions *** and Ti5Si3 were two important intermediate phases during the whole *** microstructure characteristics of the Ti3SiC2/TiB2 composites were analyzed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM).The experimental results show that the grains of Ti3SiC2/TiB2 composite are structured in a layered form,and the formation of TiB2 particles as reinforcements with elongated or equiaxed shape distributes in Ti3SiC2 matrix.
Silver powder was fabricated by spray pyrolysis, using 2%-20% AgNO3 solution, 336-500 mL/h flux of AgNO3 solution, 0.28-0.32 MPa flux of carrier gas and in the 620-820 ℃ temperature range. The effects of furnace set ...
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Silver powder was fabricated by spray pyrolysis, using 2%-20% AgNO3 solution, 336-500 mL/h flux of AgNO3 solution, 0.28-0.32 MPa flux of carrier gas and in the 620-820 ℃ temperature range. The effects of furnace set temperature, concentration of AgNO3 aqueous solution, flux of AgNO3 aqueous solution as well as carrier gas on the morphology and particle size distribution of silver powder, were investigated. The experimental results showed that with the high concentration of AgNO3 aqueous solution, the average grain size of silver decreased with the increasing of furnace set temperature. But the gain size distribution was not homogenous, the discontinuous grain growth occurred. With the low concentration of AgNO3 aqueous solution, the higher furnace set temperature made the nano sliver grains sintered together to grow. Nano silver powder about 100 nm was fabricated by spray pyrolysis, using 2wt% AgNO3 solutions, 336 mL/h flux of AgNO3 aqueous solution, 0.32 MPa flux of carrier gas at 720 ℃ furnace set temperature.
In this study,a hierarchical Bi2O3/TiO2 fibrous composite was in-situ fabricated on an electrospun TiO2 nanofiber at ambient *** the Bi2O3/TiO2 composite,S-scheme electron migration occurred between Bi2O3 and *** the ...
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In this study,a hierarchical Bi2O3/TiO2 fibrous composite was in-situ fabricated on an electrospun TiO2 nanofiber at ambient *** the Bi2O3/TiO2 composite,S-scheme electron migration occurred between Bi2O3 and *** the photocatalytic degradation of phenol under simulated sunlight,the asprepared Bi2O3/TiO2 nanofibers considerably outperformed Bi2O3 nanoparticles and TiO2 *** improvement is contributed by maintaining and effectively utilizing the useful carriers and consuming the useless holes and electrons,realized by the S-scheme heterojunction and hierarchical *** study also provides an alternative design fashion for photocatalysts.
A series of new polyamides 3a-d containing aryl-azo, ether and sulfone groups in the main chain were synthesized from bis[4-(4-aminophenoxy)phenyl sulfone] 1 and several azo aromatic diacyl chlorides 2a-d by the low...
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A series of new polyamides 3a-d containing aryl-azo, ether and sulfone groups in the main chain were synthesized from bis[4-(4-aminophenoxy)phenyl sulfone] 1 and several azo aromatic diacyl chlorides 2a-d by the low temperature solution polycondensation technique. FTIR spectroscopy, nuclear magnetic resonance (NMR) and elemental analyses confirmed the structure of these polymers. Owing to the aryl and amide groups in the main chain, these polymers exhibit photochromic properties as well as excellent thermal stabilities. The transition temperatures (Tg) are between 242 and 265℃, and the char yields at 800 ℃ in nitrogen atmosphere were above 39%. Based on incorporation of flexible ether linkages and polar sulfone groups, the polyamides show desirable solubility in organic solvents such as DMAc, N,N-dimethylformamide (DMF), N-methyl-2-pyrroidinone (NMP) and dimethylsulfoxide (DMSO). And it is exemplified that polyamide containing 2 and 2' substitutes performed better solubility.
Compounds Sr4Eu2Ti4Nb6O30 and Sr5EuTi3Nb7O30 with filled tetragonal tungsten bronze structure were prepared,and the dielectric characteristics and ferroelectric transition were *** ceramics displayed weak frequency de...
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Compounds Sr4Eu2Ti4Nb6O30 and Sr5EuTi3Nb7O30 with filled tetragonal tungsten bronze structure were prepared,and the dielectric characteristics and ferroelectric transition were *** ceramics displayed weak frequency dependence in room temperature dielectric constant,which decreased from 125 to 118 for Sr4Eu2Ti4Nb6O30,from 206 to 195 for Sr5EuTi3Nb7O30 in the frequency range of 10 kHz to 1 *** present ceramics showed a diffuse ferroelectric phase *** frequency independent transition temperature (Tm) indicated the above compounds had no relaxor *** diffuseness (γ) was 1.45 and 1.64 for Sr4Eu2Ti4Nb6O30 and Sr5EuTi3Nb7O30 *** weak ferroelectric of the present materials are indicated from the P-E hysteresis loops,and a small 2Pr of 0.596 μC/cm2 and 0.068 μC/cm2 were observed for Sr4Eu2Ti4Nb6O30 and Sr5EuTi3Nb7O30 respectively.
A high-quality tin oxide electron transport layer(ETL) is a key common factor to achieve high-performance perovskite solar cells(PSCs). However, the conventional annealing technique to prepare high-quality ETLs by con...
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A high-quality tin oxide electron transport layer(ETL) is a key common factor to achieve high-performance perovskite solar cells(PSCs). However, the conventional annealing technique to prepare high-quality ETLs by continuous heating under near-equilibrium conditions requires high temperatures and a long fabrication time. Alternatively, we present a non-equilibrium, photoexcitation-induced passivation technique that uses multiple ultrashort laser pulses. The ultrafast photoexcitation and following electron–electron and electron–phonon scattering processes induce ultrafast annealing to efficiently passivate surface and bulk defects, and improve the crystallinity of Sn O2, resulting in suppressing the carrier recombination and facilitating the charge transport between the ETL and perovskite interface. By rapidly scanning the laser beam, the annealing time is reduced to several minutes, which is much more efficient compared with conventional thermal annealing. To demonstrate the university and scalability of this technique, typical antisolvent and antisolvent-free processed hybrid organic–inorganic metal halide PSCs have been fabricated and achieved the power conversion efficiency(PCE) of 24.14% and 22.75% respectively, and a12-square-centimeter module antisolvent-free processed perovskite solar module achieves a PCE of 20.26%,with significantly enhanced performance both in PCE and stability. This study establishes a new approach towards the commercialization of efficient low-temperature manufacturing of PSCs.
A systematic research was performed about diffusion kinetics of adsorbing F^- dissolved in water for carbonate hydroxyapatite (CHAP) from the natural hydroxyapatite which was modified by adulterating with CO3^2-. Th...
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A systematic research was performed about diffusion kinetics of adsorbing F^- dissolved in water for carbonate hydroxyapatite (CHAP) from the natural hydroxyapatite which was modified by adulterating with CO3^2-. The result shows that the speed of F^- adsorption is controlled by membrane diffusion when F^- concentration is relatively low, which is expressed by the kinetic equation of diffusion Q=0.0005(Ci-C)(t-ti)+0.3967, or by vacancy diffusion when F^- concentration is relatively high, which is expressed by the kinetic equation of diffusion In[C(o, t)]=8.4718-0.5048Int. Based on the feature of CHAP for adsorbing F^- dissolved in water and its special channel of the structure of CO3^3- modified hydroxyapatite, models of vacancy diffusion and membrane diffusion were established.
Using chitin as the templating material,we obtained layered nanocomposites like shrimp or crab shells via a sol-gel self-assembly *** images show a layered structure and XRD patterns present a typical peak of chitin,w...
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Using chitin as the templating material,we obtained layered nanocomposites like shrimp or crab shells via a sol-gel self-assembly *** images show a layered structure and XRD patterns present a typical peak of chitin,which indicates the templating role of chitin in the as-received hybrid ***,the layer spacing of chitin/silica hybrid materials is reduced with increasing content of *** the heat treatment for carbonization,layered SiOC nanocomposites with mesoporous structures were obtained and showed good dye adsorption *** present study demonstrates a reliable and self-assembly synthesis technique for the development of advanced high-performance nanocomposites with biomimetic nanostructures.
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