Electrical resistivity change of saturated sand during reliquefaction under hammering loading

The electrical resistivity method was verified as an optional technique to monitor the change of mesostructure of saturated soils.To investigate the change laws of resistivity and analyze the reliquefaction meso-mechanism during the consecutive liquefaction process,five successive impact liquefaction tests were performed in a one-dimensional cubical chamber.The resistivity variation and excess pore water pressure(EPWP)were measured.The results indicate that the excess pore water pressure experienced four stages:quick increase stage,slow dissipation stage,rapid dissipation stage,and stability stage.Meanwhile,a swift decrease of resistivity emerged before the start of the rapid dissipation stage of EPWP,and then an increasing trend of resistivity is demonstrated with the densification of soil.It is proved that the vertical pore connectivity of liquefied sand is better than its random deposit state,based on a comparative study of porosity calculated from the settlement and resistivity of sand after each test.

Ionic Liquids Mediated Ionothermal Process for the One-Step Synthesis of High Surface Area Alumina Supported Noble Metals

Aluminas supported noble metal nanoparticles have been synthesized by a new ionothermal process. The method used is easy to implement and allows obtaining catalysts in one step with high specific surface area. In addition, the metallic phase in the composites is highly dispersed and exhibits homogeneous size.

Synthesis and characterization of mesostructured ceria-zirconia solid solution

Mesostructured Ce0.6Zr0.4O2 solid solutions were synthesized by coprecipitation combined with evaporation-induced self-assembly process. The obtained materials were characterized by X-ray diffractometer （XRD）, Raman, transmission electron microscopy （TEM）, N2 sorption, and hydrogen temperature programmed reduction （H2-TPR）. The results showed that the solid solutions consisted of uniform nanocrystals, which piled homogeneous mesopores of about 4 nm. Furthermore, different surfactants had little influence on the mesoporous structures. All these samples exhibited high thermal stability.

Effects of pore size,mesostructure and aluminum modification on FDU-12 supported NiMo catalysts for hydrodesulfurization

A series of NiMo/FDU-12 catalysts with tunable pore diameters and mesostructures have been controllably synthesized by adjusting the synthetic hydrothermal temperature and applied for the hydrodesulfurization of dibenzothiophene and its derivative.The state-of-the-art electron tomography revealed that the pore sizes of FDU-12 supports were enlarged with the increase in the hydrothermal temperature and the mesostructures were transformed from ordered cage-type pores to locally disordered channels.Meanwhile,the MoS2 morphology altered from small straight bar to semibending arc to spherical shape and finally to larger straight bar with the change of support structures.Among them,FDU-12 hydrothermally treated at 150℃possessed appropriate pore diameter and connected pore structure and was favorable for the formation of highly active MoS2 with curved morphology;thus,its corresponding catalyst exhibited the best HDS activity.Furthermore,it was indicated that the isomerization pathway could be significantly improved for HDS of 4,6-dimethyldibenzothiophene after the addition of aluminum,which was expected to be applied to the removal of the macromolecular sulfur compounds.Our study sheds lights on the relationship between support effect,active sites morphology and HDS performance,and also provides a guidance for the development of highly active HDS catalysts.

Recent progress of morphable 3D mesostructures in advanced materials

Soft robots complement the existing efforts of miniaturizing conventional,rigid robots,and have the potential to revolutionize areas such as military equipment and biomedical devices.This type of system can accomplish tasks in complex and time-varying environments through geometric reconfiguration induced by diverse external stimuli,such as heat,solvent,light,electric field,magnetic field,and mechanical field.Approaches to achieve reconfigurable mesostructures are essential to the design and fabrication of soft robots.Existing studies mainly focus on four key aspects:reconfiguration mechanisms,fabrication schemes,deformation control principles,and practical applications.This review presents a detailed survey of methodologies for morphable mesostructures triggered by a wide range of stimuli,with a number of impressive examples,demonstrating high degrees of deformation complexities and varied multi-functionalities.The latest progress based on the development of new materials and unique design concepts is highlighted.An outlook on the remaining challenges and open opportunities is provided.

Tectonic Imprints of the Hazara Kashmir Syntaxis on the Mesozoic Rocks Exposed in Munda, Mohmand Agency, Northwest Pakistan

Two well-developed mesoscopic folds, D_2 and D_3, which postdate the middle amphibolite metamorphism, were recognized in the western hinterland zone of Pakistan. NW–SE trending D_2 folds developed during NE–SW horizontal bulk shortening followed by NE–SW trending D_3 folds, which developed during SE–NW shortening. Micro- to mesoscopically the NW–SE trending S2 crenulation cleavage, boudins and mineral stretching lineations are overprinted by D_3. The newly established NW–SE trending micro- to mesoscopic structures in Munda termed D_2, which postdated F_1/F_2, is synchronously developed with F3 structures in the western hinterland zone of Pakistan. We interpret that D2 and D3 folds are counterclockwise rotated in the tectonic event that has evolved the Hazara Kashmir Syntaxis after the main phase Indian plate and Kohistan Island Arc collision. Chlorite replacement by biotite in the main matrix crenulation cleavages indicates prograde metamorphism related with D2. The inclusion of muscovite and biotite in garnet porphyroblasts and the presence of staurolite in these rocks indicate that the Barrovian metamorphic conditions predate D2 and D3. We interpret that garnet, staurolite and calcite porphyroblasts grew before D2 because the well developed S2 crenulation cleavage wraps around these porphyroblasts.

Molecular pore-wall engineering of mesozeolitic conjugated polymers for photoredox hydrogen production with visible light

A chemical protocol based on molecular engineering of polymeric matrix is developed for the chemical optimization of ordered mesoporous carbon nitride (OMCN) in this study to address the concerns on the serious nanostructure-induced semiconductive defects, in particular the remarkable hypsochromic shift of absorption threshold and the increased excition dissociation energy. Physical characterizations demonstrate that the successful incorporation of 3-aminothiophene-2-carbonitrile (ATCN) aromatic donor in OMCN matrix can efficiently extend the pi-conjugated system, red-shift the optical absorption toward longer wavelengths and promote exciton splitting, thus well overcoming the serious semiconductive defects. In addition, the unique structural benefits of OMCN, such as the well-orientated nanoarchitectures with large specific surface area and uniform nanosized pore, have been well remained in ATCN-modified sample (OMCNA) via adjusting the ATCN/cyanamide molar ratio to minimize the unavoidable matrix disturbance. Hence, an obviously enhanced photocatalytic activity toward H-2 evolution and selective oxidation of alcohols are obtained on optimized OMCNA samples, greatly underlining the advantage of molecular engineering in supporting nanostructured photocatalysts. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.

Cationic and Anionic Antimicrobial Agents Co‑Templated Mesostructured Silica Nanocomposites with a Spiky Nanotopology and Enhanced Biofilm Inhibition Performance

Silica-based materials are usually used as delivery systems for antibacterial applications.In rare cases,bactericidal cationic surfactant templated silica composites have been reported as antimicrobial agents.However,their antibacterial efficacy is limited due to limited control in content and structure.Herein,we report a“dual active templating”strategy in the design of nanostructured silica composites with intrinsic antibacterial performance.This strategy uses cationic and anionic structural directing agents as dual templates,both with active antibacterial property.The cationic-anionic dual active templating strategy further contributes to antibacterial nanocomposites with a spiky surface.With controllable release of dual active antibacterial agents,the spiky nanocomposite displays enhanced anti-microbial and anti-biofilm properties toward Staphylococcus epidermidis.These findings pave a new avenue toward the designed synthesis of novel antibacterial nanocomposites with improved performance for diverse antibacterial applications.

The Material Deformation and Internal Structure Development of Granular Materials under Different Cyclic Loadings

Common structures in engineering such as slopes,roadbeds,ballasts,etc.,are closely related to granular materials.They are usually subjected to long-term cyclic loads.This study mainly focused on the mechanical behaviors of randomly arranged granular materials before they reach a stable state under different cyclic loads.The variation of the maximum axial strain and the influence of CSR(cyclic stress ratio)were analyzed.The energy consumed in each cycle under constant confining stress loading condition is significantly greater than that of the fixed wall loading condition.The internal deformation evolution of granular materials is studied in detail.The deformation mode of granular material under cyclic loading at different positions inside the material is different according to the strain variation.In addition,the strain,force chain structure and contact force magnitude are combined to explore their effects on local deformation of granular materials under cyclic loading.From the perspective of the deformation form,the material sample can be divided into several regions,and the ability to adjust particle positions determines the deformation mode of different regions.The changes of local strain with the cyclic loading also reflect the contribution of particle displacements to the evolution ofmicrostructure.This research will provide insights into the understanding of granular materials behaviors under cyclic loading.

Cubic Mesoporous Aluminosilicate with Primary Structure Units of Zeolite Beta in the Pore Wall

Mesoporous aluminosilicate with cubic ordered structure was synthesized by two-step crystallization, which showed stronger acid sites and more effective activity for catalytic alkylation of 2, 4-ditert-butylphenol with tert-butanol than conventional H-AlMCM-48 materials.

Advances in Synthesis of Mesostructured Aluminophosphates

More and more attention has been paid to the synthesis of mesostructuredaluminophosphates for many years. A lot of valuable research results, including various syntheticapproaches and structural materials, have been obtained. This paper reviews the progress in thesynthesis of mesostructured aluminophosphates over the past few years, with the hope of revealingopportunities for future work.

An efficient approach for mesoscale fracture modeling of fully-graded hydraulic concrete

Large coarse aggregates used in fully-graded hydraulic concrete necessitate large specimens for numerical modeling.This leads to a high computational cost for mesoscale modeling and thus slows the development of multiscale modeling of hydraulic mass concrete structures.To overcome this obstacle,an efficient approach for mesoscale fracture modeling of fully-graded hydraulic concrete was developed based on the concept of the governing mesostructure.The mesostructure was characterized by a critical aggregate size.Coarse aggregates smaller than the critical size were homogenized into mortar matrices.Key issues in mesostructure generation of fully-graded hydraulic concrete are discussed,as is the development of mesoscale finite element modeling methodology.The basic concept and implementation procedures of the proposed approach are also described in detail.The numerical results indicated that the proposed approach not only significantly improves the compu-tational efficiency of mesoscale modeling but also captures the dominant fracturing mechanism at the mesoscale and reproduces reasonable fracture properties at the macroscale.Therefore,the proposed approach can serve as a basis for multiscale fracture modeling of hydraulic mass concrete structures.

Synthesis of Mesostructured Iron Oxides with Potential As(V) Adsorption Application

Mesostructured iron oxides（MIOs） were nanocasted from a plugged hexagonal templated silica（PHTS） with a Brunauer-Emmett-Teller（BET） surface area of 694 m 2 /g.Results of X-ray diffraction（XRD）,transmission electron microscopy（TEM） and N 2 adsorption-desorption suggest that the nanocasted MIOs are synthetic hematite（α-Fe2O3） with a wormhole-like mesoporous network.As（V） adsorption test shows that the selected MIO—MIO-500（calcinated at 500 °C） with a BET surface area of 82 m^ 2 /g has a maximum adsorption capacity of 5.39 mg/g for As（V）,which is 2.5 times as large as that of natural hematite adsorbent.The study suggests that MIOs could be potentially used as the adsorbent of As（V） in wastewater.

Status and prospects of frozen soil studies using CT technology

This paper introduces the characteristics of Computed Tomography （CT） technology and reviews its history, current situation, representative achievements, and use of using CT technology on frozen soil study, including auxiliary equipment specially de- signed for frozen soil studies. CT numbers are used to analyze frozen soil internal structure change, defining and exploring dam- age evolution, and use of CT images on observing soil mesostructure. Finally, this paper presents existing problems confronted by using CT in frozen soil studies, possible solutions and challenges, among which, we introduce high quality CT image processing for frozen soils, and relations between CT number change and each component change on frozen soil samples within the region of interest. It is shown that present CT technology is one of the most ideal and effective technology to study frozen soil mesostructure using non-desmactive testing. CT technology will play a key role in the study and development in the field of frozen soil by means of auxiliary equipment and the digital imaging processing.

Mechanical Properties of Soil-Rock Mixture Filling in Fault Zone Based on Mesostructure

Soil-rock mixture(SRM)filling in fault zone is an inhomogeneous geomaterial,which is composed of soil and rock block.It controls the deformation and stability of the abutment and dam foundation,and threatens the long-term safety of high arch dams.To study the macroscopic and mesoscopic mechanical properties of SRM,the development of a viable mesoscopic numerical simulation method with a mesoscopic model generation technology,and a reasonable parametric model is crucially desired to overcome the limitations of experimental conditions,specimen dimensions,and experiment fund.To this end,this study presents a mesoscopic numerical method for simulating the mechanical behavior of SRM by proposing mesoscopic model generation technology based on its mesostructure features,and a rock parameter model considering size effect.The validity and rationality of the presented mesoscopic numerical method is experimentally verified by the triaxial compression tests with different rock block contents(RBC).The results indicate that the rock block can increase the strength of SRM,and it is proved that the random generation technique and the rock parameter model considering size effect are validated.Furthermore,there are multiple failure surfaces for inhomogeneous geomaterial of SRM,and the angle of the failure zone is no longer 45◦.The yielding zones of the specimen are more likely to occur in thin sections of soil matrix isolated by blocks with the failure path avoiding the rock block.The proposed numerical method is effective to investigate the meso-damage mechanism of SRM.

Revealing the Uncertainty and Absolute Certainty Principles in the Kinetics of Objects Formation

The paper presents some examples revealing the uncertainty and absolute certainty principles in kinetics of objects formation that are different in their physical nature and in space scales: sub-stances of microcosm, nanoparticles and mesostructures, astrophysical and cosmological objects. Under the proposed kinetic approach, the uncertainty principle covers a wider spectrum of processes of approaching to equilibrium and object formation, than the absolute certainty principle. It refers, in particular, to nano-range-of-problems and mesoscopics as well as to cosmology. Both principles predict formation of objects that are not well-known or, at least, well-described so far. Among these are neutron-rich super-heavy and giant nuclei, biologic and organic-silicon mesoobjects, cosmological objects with the sizes considerably exceeding the size of a light sphere.

Synthesis and Characterization of Mesostructured Cellular Foam (MCF) Silica Loaded with Nickel Nanoparticles as a Novel Catalyst

This work investigated the possibility of incorporation of nickel into several mesostructured cellular foam (MCF) silica supports prepared at various aging times (1, 2, and 3 days) by using deposition-precipitation method followed by reducetion process and to look for the best support to obtain supported nickel catalyst with highest nickel loading and smallest size of nickel nanoparticles. Analyses using nitrogen adsorption-desorption, transmission electron microscopy (TEM), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) showed that MCF silica prepared at aging time of 3 days was the best support as the corresponding nickel functionalized MCF catalyst had the highest nickel content (17.57 wt%) and the smallest size of nickel nanoparticles (1 - 2 nm) together with high porosity (window pore size of 90A). The result was attributed to the highest window pore size in the MCF support which allowed more nickel nanoparticles to be incorporated.

Synthesis of Si-and Ti-MCM-41 Mesostructures via a Novel S^+X^-I^+ Assembly

Well-defined Si- and Ti-MCM-41 mesoporous molecular sieves were synthesized in high yields through the halogen anion mediated S(+)X(-)I(+) assembly in the presence of cetylpyridinium bromide as template. The spectroscopy characterization of the as-synthesized samples confirmed that Ti (IV) could be isolated in the lattice positions of the MCM-41 mesostructure by this method.

Chiral mesostructured hematite with temperature-independent magnetism due to spin confinement

Hematite(α-Fe_(2)O_(3))is known to undergo conversion from weak ferromagnetic to antiferromagnetic as the temperature decreases below the Morin temperature(TM=250 K)due to spin moment rotation occurring during the Morin transition(MT).Herein,we endowed hematite with mesostructured chirality to maintain weak ferromagnetism without MT.Chiral mesostructured hematite(CMH)nanoparticles were prepared by a hydrothermal method with glutamic acid(Glu)as the symmetry-breaking agent.The triangular bipyramidal CMH nanoparticles were composed of helically cleaved nanoflakes with twisted crystal lattice.Field-cooled(FC)magnetization measurements showed that the magnetic moments of CMH were stabilized without MT within the temperature range of 10–300 K.Hysteresis loop measurements confirmed the weak ferromagnetism of CMH.The enhanced Dzyaloshinskii–Moriya interaction(DMI)was speculated to be responsible for the temperature-independent weak ferromagnetism,in which the spin configuration would be confined with canted antiferromagnetic coupling due to the mesostructured chirality of CMH.

One-step fabrication of mesoporous sulfur-doped carbon nitride for highly selective photocatalytic transformation of native lignin to monophenolic compounds

Photocatalytic selective transform native lignin into valuable chemicals is an attractive but challenging task.Herein,we report a mesoporous sulfur-doped carbon nitride(MSCN-0.5)which is prepared by a facile one-step thermal condensation strategy.It is highly active and selective for the cleavage Cα-Cβbond inβ-O-4 lignin model compound under visible light radiation at room temperature,achieving 99%substrate conversion and 98%Cα-Cβbond cleavage selectivity.Mechanistic studies revealed that the Cβ-H bond of lignin model compounds activated by holes and generate key Cβradical intermediates,further induced the Cα-Cβbond cleavage by superoxide anion radicals(·O2-)to produce aromatic oxygenates.Waste Camellia oleifera shell(WCOS)was taken as a representative to further understand the reaction mechanisms on native lignin.33.2 mg of monophenolic compounds(Vanillin accounted for 22%and Syringaldehyde for 34%)can be obtained by each gram of WCOS lignin,which is 2.5 times as that of the pristine carbon nitride.The present work offers useful guidance for designing metal-free heterogeneous photocatalysts for Cα-Cβbond cleavage to harvest monophenolic compounds.