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This paper presents a nonlocal energy-informed neural network to address the inherent zero-energy mode instability in peridynamic correspondence material models. Starting from the principle of virtual work, the task of solving peridynamic equilibrium equation is reformulated as a variational minimum problem of total potential energy, serving as the natural loss function for neural network. By minimizing the potential energy of the peridynamic body, the proposed neural network effectively eliminates the zero-energy modes. Importantly, this approach preserves the original peridynamic formulation without introducing a supplementary force vector state or modifying the nonlocal deformation gradient tensor. Additionally, there is no need for an artificial damping coefficient in adaptive dynamic relaxation, and the high memory consumption in implicit schemes is avoided. To improve the prediction accuracy near boundaries and to impose boundary conditions consistently with the local continuum theory, variable horizon method is introduced. Comparative studies of the proposed neural network with analytical solutions, finite element analyses or other control methods are conducted to verify the feasibility and accuracy of the proposed neural network in suppressing zero-energy mode oscillations. Furthermore, the convergence of the proposed approach and the influence of different activation functions on the prediction accuracy and convergence rate are investigated. [ABSTRACT FROM AUTHOR]

Pore scale variables (e.g., porosity, grain size) are important indexes to predict the hydraulic properties of porous geomaterials. X-ray images from ten types of intact sandstones and another type of sandstone samples subjected to triaxial compression are used to investigate the permeability and fracture characteristics. A novel double threshold segmentation algorithm is proposed to segment cracks, pores and grains, and pore scale variables are defined and extracted from these X-ray CT images to study the geometric characteristics of microstructures of porous geomaterials. Moreover, novel relations among these pore scale variables for permeability prediction are established, and the evolution process of cracks is investigated. The results indicate that the pore-scale permeability is prominently improved by cracks. In addition, excellent agreements are found between the measured and the estimated pore scale variables and permeability. The established correlations can be employed to effectively identify the hydraulic properties of porous geomaterials.

C25H22O3, orthorhombic, P212121(no. 19), a= 6.1768(2) Å, b= 11.2198(5) Å, c= 27.5938(11) Å, V= 1912.32(13) Å3, Z= 4, Rgt(F) = 0.0319, wRref(F2) = 0.0872, T= 100(2) K.

In this paper, a chemo-mechanical coupling bond-based peridynamic model considering stress-chemical corrosion (SCC) is first proposed to simulate chemical corrosion. The proposed model can also investigate the damage and cracking behaviors of materials under chemo-mechanical coupling condition, which is different from the previous electrochemical corrosion PD model only considering chemical corrosion condition. Furthermore, two examples of electrochemical corrosion and stress chemical corrosion are employed to illustrate the ability of the chemo-mechanical coupling bond-based peridynamic model. The present numerical results are in good agreement with the previous results obtained by the phase field method and the analytical solution, which further verifies the accuracy and ability of the proposed model. Finally, it is concluded that the more severe the chemical corrosion, the faster the crack growth rate and the deeper the chemical corrosion pits. [ABSTRACT FROM AUTHOR]

The Drucker-Prager (D-P) model is a representative elastoplastic model for geomaterials because hydrostatic pressure is considered. This paper proposes an ordinary state-based peridynamic (OSB-PD) model with shear deformation based on D-P model and the associated flow rule to study the plastic and damage behaviors of geomaterials. By considering the second invariant of the stress deviator J2and the first invariant function of stress tensor I1as the function of peridynamic energy density, the D-P yield function in nonlocal form can be used in peridynamics. In addition, the equivalent stress and equivalent plastic strain in this PD model with shear deformation are determined. Several examples are used to verify the validity of the proposed PD model. The PD results are compared with those obtained by the finite element method (FEM). It implies that the proposed method is effective and accurate.

Herein we report two tubular metal–organic cages (MOCs), synthesized by the self-assembly of bidentate metalloligands with different lengths and PdII. These two MOCs feature Pd4L8-type square tubular and Pd3L6-type triangular cage structures, respectively. Both MOCs have been fully characterized by NMR spectroscopy, mass spectrometry, and theoretical calculation. Both cages can be employed for encapsulating polycyclic aromatic hydrocarbons and show high binding affinity toward coronene.

The prediction of fracturing behaviors of heterogeneous geomaterials remains a challenge. In the framework of bond-based peridynamics with shear deformation, a criterion is derived by the mixed mode I/II fracture energy to simulate complex compression/shear failure of rocks subjected to uniaxial compression. Combined with CT technology, heterogeneity is introduced to predict the mechanical response and fracturing behaviors of granite. The 2D dimensional and 3D dimensional numerical simulations are carried out, and the effects of kernel functions on the mechanical responses and fracturing behaviors are investigated. The numerical results are in good agreement with the experimental data, implying the proposed method can effectively simulate effects of heterogeneity on the mechanical responses and fracturing behaviors.

The design and synthesis of artificial molecular containers for the encapsulation of hydrocarbon gases to study their host-guest chemistry are highly important for potential application in gas storage, separation, and understanding of their biological functions. In this work, we report the subcomponent self-assembly of four cubic Zn8L12Br4(HL = N-(4-R)-1-(5-methyl-1H-imidazole-4-yl)methanimine) cages with good solubility in chloroform, which are capable of binding hydrocarbon gases including methane, ethane, and ethene in solution at ambient temperature. Two types of gas binding sites (one is in the cavity, and the other is at the window) are discovered in these cages, which are documented by nuclear magnetic resonance (NMR) spectra and density functional theory (DFT) calculations. Their performance of encapsulation of hydrocarbon gases can be tuned by carefully adjusting substituent groups. These metal-organic cages containing two types of binding sites provide new artificial models to mimic the structures and functions of biological systems in binding and transforming hydrocarbon gases.

The mid-point quadrature rule is often used to solve the nonlocal integral differentiation equations, in which a central material point is used to calculate the integral of the subdomain in the meshless geometry. However, it can only achieve the linear approximation and the first order convergence rate, and it is only accurate enough when the entire cell overlaps with the neighborhood of a material point. In this paper, to achieve the higher precision and the higher rate of convergence speed, a novel coupling method of reproducing kernel particle method and Gaussian-Legendre quadrature scheme is proposed to solve the nonlocal integral differentiation equations in the meshless geometry, in which the mid-point quadrature scheme is replaced with Gauss quadrature scheme to calculate the integral of the subdomain in the meshless geometry, the reproducing kernel particle method is employed to construct the shape functions for material points in the nonlocal model, and to approximate the value of the Gaussian quadrature node. Moreover, the meshless solution for the peridynamic equation is derived detailedly based on the proposed method. Compared with the traditional meshless solution for the nonlocal equations, the proposed solution has higher precision and higher rate of convergence speed in different problems. The numerical results demonstrate improved results in both mathematics and mechanical problems using the proposed method. [ABSTRACT FROM AUTHOR]

Charged metal-organic cages generally produce aggregates with various morphologies and different properties through the multiple supramolecular interactions in solution. Herein, a luminescent hexahedral metal-organic cage containing pyrene chromophores is successfully constructed through coordination-driven subcomponent self-assembly. The cage exhibits novel spontaneous aggregation in a dilute solution and time-dependent luminescence enhancement behavior during the subsequent incubation process. Dynamic light scatter (DLS) and transmission electron microscopy (TEM) results prove that the metal-organic cages can form blackberry-like aggregates in methanol dilute solution. Unexpectedly, the luminescent intensity of this system shows a linear increase with the extension of the incubation time in methanol, and this process is also reflected in the change in the quantum yield of the system (2% to over 80% after 5 days incubation time). Ultraviolet-visible (UV-vis), 1H nuclear magnetic resonance (1H NMR) and mass spectra show that metal-organic cages can stably exist in dilute solution. Time-depended DLS and TEM data reveal that the aggregates of metal-organic cages are gradually changed from the dense state to the loose one, which may involve the transition of the system from an energy unstable state to a stable one, probably leading to the unusual time-dependent luminescent property. This unique time-dependent luminescent cage aggregate can be potentially applied as a “supramolecular time meter”.

Herein we report a discrete heterometallic Pd4Cu8L8cage with a tubular structure, which was synthesized by the assembly of copper metalloligands and PdIIions in a stepwise manner. The Pd4Cu8L8cage has been unequivocally characterized by single-crystal X-ray diffraction, electrospray ionization-mass spectroscopy, and energy dispersive spectroscopy. The cage showed excellent catalytic activity in the epoxidation of styrene and its derivatives under conditions without using additional solvent, providing potential material for catalyzing the oxidation reactions.

Post-synthetic installation strategy is an effective approach to improve the functions of metal-organic frameworks (MOFs). Herein, a pair of chiral MOFs is successfully constructed through solvothermal subcomponent self-assembly and exhibit circularly polarized luminescence (CPL). These MOFs contain coordinatively unsaturated Zn sites and channels, which allow the installation of pyridyl-terminated pillars into the original structure. Such a post-synthetic installation process reinforces the MOFs’ rigidity and increases the photoluminescence quantum yields (PLQYs). Furthermore, the luminescence dissymmetry factors (glum) of these post-modified MOFs are amplified after installing the pillars. This work provides an appealing strategy for boosting the CPL performance of chiral MOFs.

When compared to industrially stable zeolites, the instability of metal–organic frameworks (MOFs) has been denounced by researchers. Boosting the stability of existing MOFs is highly important for practical applications. In this report, we develop a new strategy to prepare MOFs/poly(tetrafluoroethylene) (PTFE) composites, which can highly improve the chemical, pressure, and photostabilities of zeolitic imidazolate framework (ZIF)-8. Composite materials were prepared by a physical blending of ZIF-8 and PTFE emulsion with different ratios and annealing at 370 °C. Transmission electron microscopy (TEM) studies reveal that the nanoparticles of ZIF-8 are coated by PTFE to form the composite materials. Upon mixing with 20 or 50 wt % PTFE, the ZIF-8/PTFE materials show a superhydrophobic property with water contact angles of around 156°. Pristine ZIF-8 is not stable in water with stirring under acidic, basic, and irradiation conditions, while the ZIF-8/PTFE materials are stable under the same conditions. The ZIF-8/PTFE materials can also maintain their crystalline structure after being compressed with a 10 MPa pressure, while pristine ZIF-8 changes to an amorphous solid after the same pressure treatment. Using water as a solvent, ZIF-8/PTFE can be used as a highly efficient and recyclable catalyst for Knoevenagel reaction at room temperature. The successful preparation of stable ZIF-8/PTFE composite materials provides a useful method to enhance the chemical, pressure, and photostabilities of MOFs.

Abstract Mutations of the PTEN gene are associated with hamartoma-neoplasia syndromes. While germline mutations at this chromosome 10q22-23 locus have been observed in patients with Cowden syndrome (CS) and Bannayan-Riley-Ruvalcaba [...]

Metal–organic cages, a class of supramolecular containers constructed by the self-assembly of metal ions and organic ligands, show great promise as catalytic agents. In this work, we designed and synthesized a series of rhombic dodecahedral Ni–Cu heterometal imidazolate cages (Ni8Cu6L24) that can act as highly active photo-Fenton-like catalysts. These cages possess a high ability to generate hydroxyl radicals (•OH) under visible light in the presence of H2O2, which can rapidly degrade organic pollutants (e.g., rhodamine B, methylene blue, and methyl orange) into CO2and H2O. Besides, they are robust catalysts, with high catalytic activity and reusability under conditions in high H2O2concentration, providing potentially advanced materials for degrading persistent organic pollutants.

The exploration of highly efficient materials for the degradation of chemical warfare agents has been a longstanding task for preventing human exposure. Herein, we report a series of metal–organic frameworks (MOFs) M-TCPP-La based on metallo-tetra(4-carboxyphenyl)porphyrin and LaIII, which were applied to selectively oxidize 2-chloroethyl ethyl sulfide (CEES, a sulfur mustard simulant) as heterogeneous photocatalysts. After irradiation from a commercial blue light-emitting diode (LED), both superoxide ion and singlet oxygen were generated by M-TCPP-La and involved in selective oxidization of CEES to 2-chloroethyl ethyl sulfoxide (CEESO). Notably, a very short half lifetime (2.5 min) was achieved using Fe-TCPP-La as the photocatalyst. In comparison to currently utilizing singlet oxygen and hydrogen peroxide as oxidizing agents, this work employing both singlet oxygen and superoxide ion represents a new and effective strategy of detoxification of mustard gas.

Water oxidation to molecular oxygen is indispensable but a challenge for splitting H2O. In this work, a series of Co-based metal–organic cages (MOCs) for photoinduced water oxidation were prepared. MOC-1 with both bis(μ-oxo) bridged dicobalt and Co–O (O from H2O) displays catalytic activity with an initial oxygen evolution rate of 80.4 mmol/g/h and a TOF of 7.49 × 10–3s–1in 10 min. In contrast, MOC-2 containing only Co–O (O from H2O) in the structure results in a lower oxygen evolution rate (40.8 mmol/g/h, 4.78 × 10–3s–1), while the amount of oxygen evolved from the solution of MOC-4 without both active sites is undetectable. Isotope experiments with or without H218O as the reactant successfully demonstrate that the molecular oxygen was produced from water oxidation. Photophysical and electrochemical studies reveal that photoinduced water oxidation initializes via electron transfer from the excited [Ru(bpy)3]2+* to Na2S2O8, and then, the cobalt active sites further donate electrons to the oxidized [Ru(bpy)3]3+to drive water oxidation. This proof-of-concept study indicates that MOCs can work as potential efficient catalysts for photoinduced water oxidation.

A 2D novel non-local lattice bond model (NLBM) is proposed to study the initiation, propagation and coalescence of cracks in rock materials. In the proposed NLBM, multiple neighboring lattices are utilized to solve the crack path preference problems. Furthermore, both the normal bonds and the tangent bonds are considered to overcome the limitation of the fixed Poisson's ratio in the classical lattice model. The stiffness parameters are determined by comparing the strain energy stored in a discrete unit lattice with the classical continuum strain energy. Both the elastic problems and the crack path preference problems are simulated by using the proposed method. Compared with the existing numerical methods and experimental results, the performance of the proposed NLBM is satisfactory for predicting the fracturing behaviors in rock materials and for overcoming the limitation of the fixed Poisson's ratio in the classical lattice model. [ABSTRACT FROM AUTHOR]

The development of circularly polarized luminescence (CPL) materials with high performance is significantly important. Herein, we develop a facial strategy for fabricating a CPL-active system by employing an achiral luminescent metal-organic cage (MOC) and chiral BODIPY molecules. CPL is achieved by taking advantage of the radiative energy transfer process, in which BODIPY molecules act as energy acceptors and MOCs act as donors. The CPL performance (maximum luminescence dissymmetry factor up to ±1.5×10−3) can be tuned by adjusting the ratio between MOCs and BODIPY. White-light emission with the CPL feature is obtained by using a ternary system including MOC, chiral BODIPY, and Rhodamine B. The present work provides a facile and universal strategy to construct a CPL-active system by integrating achiral luminophores and chiral molecules.

Polycyclic aromatic hydrocarbons (PAHs) play an important role in the industry, and the development of new materials for the selective separation of PAHs is of great significance. In this work, we report a hexahedral metal-organic cage with low symmetry by subcomponent self-assembly. In this cage, the eight ZnIIcenters adopt an interesting ΛΛ/ΔΔΔΔΔΔ or ΛΛΛΛΛΛ/ΔΔ configuration. This cage with a cavity volume of 520 Å3can bind anthracene, phenanthrene, and pyrene to form 1:1 host-guest complexes, while the bigger triphenylene, chrysene, perylene, and coronene cannot be encapsulated. The binding constant Kaof pyrene is about 1.110 × 103(mol/L)−1,which is more than an order of magnitude larger than that of anthracene and phenanthrene (111 (mol/L)−1, 277 (mol/L)−1, respectively). X-ray structure studies reveal that the pyrene is located in the cavity and stabilized by multiple CH⋅⋅⋅πinteractions. After separation from a mixture of PAHs, pyrene with >96.1% purity can be obtained. This work provides a useful method for the first time for the selective separation of pyrene from PAHs mixture by utilizing a metal-organic cage as the material, making it a useful tool for purifying and separating specific compounds from complex mixtures.

A unique metal–organic framework (MOF) with tetrazole-padded helical channels has been successfully synthesized in one pot from iron(II) trifluoromethanesulfonate, 4-formylimidazole, hydrazine, and sodium azide under solvothermal conditions and features a rare unhtopology and porous structure for gas adsorption. Transformations of condensation, cycloaddition, and coordination occurred during the synthetic process, in which a 1,5-disubstituted tetrazole ligand was formed in situ.

In this paper, smoothed bond-based peridynamics (SBBPD) is proposed to simulate the large deformation. The governing equation of smoothed bond-based PD is obtained by incorporating the observed changes in the density field and long-range force reaction in Eulerian form. The Hencky stretch is introduced into smoothed bond-based PD to calculate the true strain because of the change in density (volume). The proposed method can achieve a more accurate result in solid mechanics compared with SPH and can well handle extremely large deformation problems compared with traditional bond-based PD. Numerical experiments are launched to test these modifies of smoothed bond-based PD method in solid mechanics.

A triangular prismatic metal–organic cage based on mixed valence copper ions has been designed and synthesized by using metallocycle panels and pillar ligands. The triangular prism will be quickly transformed to a 10-nuclear cage upon an external chemical stimulus, which features a bicapped square antiprism structure. This prismatic cage can act as a catalyst for oxidation of aromatic alcohols to their corresponding aromatic aldehydes with high yields at room temperature under O2atmosphere.

Metalloenzymes are powerful biocatalysts that can catalyze particular chemical reactions with high activity, selectivity, and specificity under mild conditions. Metal–organic frameworks (MOFs) composed of metal ions or metal clusters and organic ligands with defined cavities have the potential to impart enzyme-like catalytic activity and mimic metalloenzymes. Here, a new metal–organic framework implanted with hydroxo iron(III) sites with the structural and reactivity characteristics of iron-containing lipoxygenases is reported. Similar to lipoxygenases, the hydrogen atoms and electrons of the substrate can transfer to the hydroxo iron(III) sites, showing typical proton-coupled electron transfer behavior. In the reactivity mimicking biology system, similar to alcohol oxidase, the material also catalyses the oxidation of alcohol into aldehyde by using O2with a high yield and 100% selectivity under mild conditions, without the use of a radical cocatalyst or photoexcitation. These results provide strong evidence for the high structural fidelity of enzymatically active sites in MOF materials, verifying that MOFs provide an ideal platform for designing biomimetic heterogeneous catalysts with high conversion efficiency and product selectivity.

The SiF62–anions are in situ formed in the reactions of MF2(M = Cu2+, Zn2+, Ni2+, and Co2+) salts and nitrogen-containing ligands in borosilicate glass tubes under solvothermal conditions and then used to further construct a family of metal–organic frameworks (MOFs). This in situ reaction demonstrates a new and facile strategy for the fabrication of MOFs based on SiF62–.

Natural gas-hydrates are plural clean energy resource with rich deposits, and hydrate behavior significantly affects the exploration, production and utilization of these energy resources. However, technical difficulties for effective production and utilization of these energy sources still exist. Hydrate formation using xenon and NaBr brine and X-ray computed tomography (CT) imaging experiments are conducted to investigate microstructural morphology phase behaviors of hydrates, and a novel multi-phase color difference separation method to segment the pore, hydrate, water and grain phases is proposed. Effects of underground temperature gradient on thermal properties during the phase changes of hydrates are analyzed, and their effects on flow properties are studied. Results indicate that the temperature fraction, hydrate phase fraction, latent-heat thermal energy (LTE) and total enthalpy decrease with increasing temperature gradient. Hydrates rapidly form approximately at time = 250s for temperature gradient of 50 K and time = 500s for temperature gradients of 100 K, 150 K, 200 K and 300 K, and the hydrate phase equals to each other approximately at time = 95s. The stable LTE and total enthalpy approaches to a maximum when the temperature gradient is 150 K. Moreover, the temperature fraction and total enthalpy decrease on average by 4.73%, 4.69% and 76.13%, 75.87%, and the hydrate phase fraction increases by 7.89% and 7.88% with increasing microporosity and micropore size from 34.66% to 41.93% and from 37.53 μm to 43.22 μm, respectively. The temperature fraction and total enthalpy increase on average by 5.29% and 76.67% with increasing pore-scale hydrate saturation from 0.73 to 1.00. The LTE remains constant with an increase in hydrate pore-scale variables of microporosity, micropore size and hydrate saturation from 34.66% to 41.93%, from 37.53 μm to 43.22 μm and from 0.73 to 1.00, respectively. In addition, numerical permeability computed by the proposed relation of microporosity and pore-scale hydrate saturation agrees well with experimental results, with the average errors all less than 5%. The temperature and total enthalpy in phase change heat transfer of hydrates improve the permeability. The LTE in phase change heat transfer of hydrates hardly changes the permeability, and hydrate phase decreases the permeability. This work provides the quantitative and qualitative evaluations of phase change and heat transfer behaviors of gas-hydrates, which are helpful and provide excellent tools to develop the techniques for the exploration, production and utilization of these energy resources to decrease the energy crisis.

Metal–organic cages are potential artificial models for mimicking biological functions due to their capability of selective encapsulation for certain guest molecules. In this work, we designed and synthesized a series of rhombic dodecahedral Ni-imidazolate cages (Ni14L24) with precisely controlled aperture for CO2encapsulation. The aperture of the cages can be tuned by the strategies of ligand decoration and metal-ion hybridization. Similar to the breathing function of alveoli, CO2passes through the dynamic aperture into the cages under a pressure of 2.0–3.0 bar in methanol solution, and slowly move out of the cages when the pressure goes down. In the solid state, CO2is encapsulated and prisoned in the cages under a high pressure of 15.0–30.0 bar or supercritical conditions. By replacing the square-coordinated Ni2+with Cu2+, the resulting Ni–Cu heteronuclear cage lost the capability of physically encapsulating CO2even though the aperture’s size is only slightly changed.

By coupling the phantom node method with the mesh cut technique in the framework of the extended finite element method (XFEM), an enhanced XFEM for the propagation of complex branched cracks is proposed. The proposed method aims to solve the complex branched crack problems. Additionally, instead of the constant crack propagation length, a novel crack propagation scheme is introduced into the XFEM, in which the crack propagation length is a variable which is determined by two trial calculations. The feasibility and the accuracy of the proposed method are validated by numerical tests. The numerical results show that the enhanced XFEM can easily handle the complex branched crack problems, and it has the higher accuracy than the standard XFEM. Meanwhile, a smooth crack path can be obtained using the novel crack propagation scheme. [ABSTRACT FROM AUTHOR]

Transforming growth factor type 1 receptor (ALK5) is kinase associated with a wide variety of pathological processes, and inhibition of ALK5 is a good strategy to treat many kinds of cancer and fibrotic diseases. Recently, a series of compounds have been synthesized as ALK5 inhibitors. However, the study of their selectivity against other potential targets remains elusive. In this research, a data-set of ALK5 inhibitors were collected and studied based on the combination of 2D-QSAR, molecular docking and molecular dynamics simulation. The quality of QSAR models were assessed statistically by F, R2, and R2ADJ, proved to be credible. The cross-validations for the models (q2LOO = 0.571 and 0.629, respectively) showed their robustness, while the external validations (r2test = 0.703 and 0.764, respectively) showed their predictive power. Besides, the predicted binding free energy results calculated by MM/GBSA method were in accordance with the experimental data, and the van der Waals energy term was the factor that had the most significant impact on ligand binding. What is more, several important residues were found to significantly affect the binding affinity. Finally, based on our analyses above, a proposed series of molecules were designed.

Using water as the sole solvent, the bifunctional molecule tetrakis(methylthio)-1,4-benzenedicarboxylic acid (TMBD) was reacted with Cu(CH3CN)4BF4to form a robust microporous metal–organic framework (MOF, CityU-7) featuring Cu(I) ions being simultaneously bonded to the carboxyl and thioether donors. The MOF solid is stable in air and can be easily activated by heating, without the need for treatment with organic solvents. The subnanoscopic pores (ca. 0.6 nm) of the host net allow for uptake of CO2and H2O but exhibit lesser sorption for N2at 77 K. The microporous net can also be penetrated by I2molecules.

Three coordination polymers (CPs) with square-planar CuII/NiIIN4subunits were formed in one step by subcomponent self-assembly, giving rise to an unprecedented linking variety of in situ embedded metalloligands and CuIclusters. All CPs exhibit unusual visible-light adsorption. Enhanced photocatalytic activity and high selectivity were observed in the oxidation of benzene under visible-light irradiation.

This paper studies the internal morphology of cracking of two 3-D pre-existing cross-embedded flaws in poly(methyl methacrylate) specimens under uniaxial compression. In this study, observable cracking behaviors include the crack initiation, growth, wrapping and coalescence, and the ultimate fracture of the specimen. The experimental results show six modes of crack initiation and two types of crack wrapping. The initiation of silky cracks in 3-D cracking behaviors is reported first, as well as the closed-mode wrapping of petal cracks. Substantial wrapping of petal cracks, which plays an important role in crack coalescence, appears to be the major difference between the 2-D and 3-D cracking behaviors of pre-existing flaws. Moreover, three modes of crack coalescence, which include the coalescence of petal cracks, antiwing cracks, and oblique secondary cracks, are found. Crack coalescence is predominantly created by the linkage of petal cracks, which is further classified into six categories. Note that only limited vertical growth of petal cracks is observed, and the ultimate failure of specimens is induced by the continued growth of the propagated wing crack. It was found that the ultimate fracture face of the specimens consists of continuous wing cracks and fragmented silky cracks. This paper provides the internal morphology basis for the 3-D fracture mechanism of specimens containing two 3-D pre-existing cross-embedded flaws.

Herein we report a covalent cage TPE-Zn4based on a tetraphenylethylene molecule viasubcomponent self-assembly, which is templated by zinc ions. TPE-Zn4features a quadrangular prismatic cage structure, which is characterized by NMR, mass spectrum, and single-crystal X-ray diffractions. TPE-Zn4emitted orange fluorescence (λem = 620 nm) in DMSO solution under the irradiation of UV light (λex = 395 nm) and can be applied as a fluorescence sensor for selectively detecting Pd2+. The fluorescence of TPE-Zn4was quenched by Pd2+in DMSO solution, and a very low detection limit of 62.3 nM was achieved. Mechanism studies reveal that the Pd2+can replace the Zn2+, and the heavy atom effect and chelation-enhanced quenching effect between the Pd2+and the cage probably cause the fluorescence quenching.

This paper aims at studying spatial variations and voxel scale effects on digital-permeability of sandstone reservoirs at small-scale. X-ray μ-CT imaging is applied to capture various pore-structures. Digital pore-scale analysis is employed to quantitatively analyze voxel scale effects on microstructures with connective pore space and invalid pores. The coupling multipoint statistics-marching cube (MPS-MC) three-dimensional (3D) reconstruction is used to construct 3D virtual micro-channel models with connective seepage channels. Pore network numerical simulations with valid realistic geometries are conducted to deeply understand voxel scale effects on microscopic hydraulic properties of sandstone reservoirs. The results show that digital porosity, micro-pore and micro-grain size gradually become stable with a voxel scale larger than 3003. The spatial variation of permeability and voxel scale effects relates extremely to the seepage index and digital porosity. As digital porosity is less than 30%, the seepage index increases with an exponential manner, and as digital porosity is larger than 30%, it decreases with a logarithm manner. The permeability is easy to evaluate by the established logarithm relation between the permeability and seepage index with relative errors all less than 5%. The proposed permeability-seepage index in the digital analysis framework provides excellent approaches to effectively evaluate the hydraulic properties of rock reservoirs.

Focal adhesion kinase (FAK) is a non-receptor tryosine kinase that plays a vital role in tumor cell survival, proliferation and migration. It has been shown that inhibiting the activity of FAK may result in impeding tumor cells invasion and growth. There are several small molecule FAK inhibitors which have been developed with outstanding FAK inhibitory activity. And most of the small molecules are nitrogen-containing aromatic compounds. This review describes the chemical structure characteristics and activity of current small molecule FAK inhibitors that aims to serve as a future reference for the development of potential FAK inhibitors.

A novel bolaamphiphile was synthesized from proline and 1,8-diaminooctane, and its physicochemical properties were investigated.

C21H18O5, monoclinic, P21(no. 4), a= 9.1511(4) Å, b= 5.6679(3) Å, c= 16.7731(9) Å, β= 93.435(2)°, V= 868.42(8) Å3, Z= 2, Rgt(F) = 0.0410, wRref(F2) = 0.1204, T = 296(2) K.

C21H20O4, monoclinic, P21(no. 4), a= 5.7726(10) Å, b= 12.662(2) Å, c= 12.068(3) Å, β= 92.377(11)°, V= 881.3(3) Å3, Z= 2, Rgt(F) = 0.0342, wRref(F2) = 0.0887, T = 296(2) K.

Flame thermal spray Ni-Cr-Al coating layer on Q235 steel modified by friction stir processing(FSP) was studied. FSP function area formed a uniform density composite layer, of which internal coating layer formed superfine crystal structure and crystal structure of substrate changed, improved the mechanical properties. The plastic deformation generated by friction stir processing directly influenced the microstructure and mechanical properties. Dynamic recrystallization occurred within a certain range of plastic deformation, temperature and plastic deformation interlocking effect provided advantageous channel to fast element interdiffusion.

This Four passes processing to the thermal spray aluminum coating on the aluminum alloy surface,based on friction stir processing (FSP). Applications SEM, EDS and micro hardness testing to analysis the coatings that have been processed and haven't been processed. The results show that , after the friction stir processing,dense ultrafine grained aluminum with the sizes less than 200nm is obtain ,and replace original laminated and porous coating . Fusion utilizes between the coating and the substrate, the gap between coating and substrate have disappear. The alloy elements in the substrate diffuse to the coating.

Effect of 10% Ni on synthesis of Al2O3-TiB2 Composite ceramic powder during the mechanical alloy. X-ray diffraction phase analysis (XRD) and scanning electron microscope (SEM) were used to study the phase and morphology of particles which ball milling different time. The results show that: when adding 10%Ni, it generates Al2O3, TiB2 ceramic phase after 20h; In the process of mechanical alloying, the powder particles can agglomerate and then break up. It will accelerate the powder agglomeration for Ni is absorbed on the surface of Al particles, thus shorten the diffusion distance of the atom and accelerate the solid state reaction.

MoO3 was synthesized by thermal decomposition of ammonium molybdate. The structure and surface morphology of the as-prepared MoO3 was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The supercapacitive behaviour of MoO3 in 1 mol L-1 KCl electrolyte was studied by cyclic voltammetry (CV), galvanostatic charge-discharge cycling (CD). The affect of thermal decomposition temperature on the capacitive behaviour of MoO3 was also discussed here. The results indicate that MoO3 show good capacitive behaviour with a specific capacitance of 148.9 F g-1 at 0.7 A g-1. Thermal decomposition temperature has an important influence on the capacitive behaviour and crystallization of MoO3.

A frame is an automobile parts, narrow, thin wall and bending，This paper mainly analyzes its machining technology andthe key, the difficulty of processing；And studies how to save materials, save the auxiliary tools, improve the machining efficiency.

The interface microstructure in the joints of magnesium alloy AZ31 to Ti alloy by the laser welding-brazing (LWB) process have been investigated in this paper. The results indicated that the interface between the solder reaction and TC4 formed net and holes, there was a 1~2 μm intermetallic compound layer. Al-Mg-Zn compounds generated and distributed in the solder reaction zone.

Gas separation performances are usually degraded under humid conditions for many crystalline porous materials because of the lack of water stability and/or the competition of water vapor toward the interaction sites (e.g., open metal sites). Zeolitic imidazolate frameworks (ZIFs) are suitable candidates for practical applications in gas separation because of their excellent physical/chemical stabilities. However, the limitation of substituent positions in common ZIFs has prevented extensive pore engineering to improve their separation performance. In a type of gyroidal ZIFs with gietopology, the Schiff base moiety provides additional substituent positions, making it possible to modify the spatial arrangement of hydrophobic methyl groups. Herein, a new gyroidal ZIF, ZnBAIm (H2BAIm = 1,2-bis(1-(1H-imidazol-4-yl)ethylidene)hydrazine), is designed, synthesized, and characterized. The spatially modified ZnBAIm exhibits improved thermal/chemical/mechanical stabilities compared to ZnBIm (H2BIm = 1,2-bis((5H-imidazol-4-yl)methylene)hydrazine). ZnBAIm can remain intact up to about 480 °C in a N2atmosphere and tolerate harsh treatments (e.g., 5 M NaOH aqueous solution at room temperature for 24 h and 190 MPa high pressure in the presence of water). Moreover, the modified pore and window sizes have improved significantly the ethane/ethylene selectivity and separation performance under humid conditions for ZnBAIm. Breakthrough experiments demonstrate efficient separation of a C2H6/C2H4(50/50, v/v) binary gas mixture under ambient conditions; more importantly, the C2H6/C2H4separation performance is unaffected under highly humid conditions (up to 80% RH). The separation performance is attributed to combined thermodynamic (stronger dispersion interaction with C2H6than with C2H4) and kinetic factors (diffusion), determined by density functional theory calculations and kinetic adsorption study, respectively.

The parallel character of particle swarm algorithm (PSO) and the Graphic Processing Unit (GPU) technology of Compute United Device Architecture (CUDA) from NVIDIA are analyzed. Two methods of the realization of PSO based on GPU are discussed. One method is using the module of open source particle swarm algorithm supporting the GPU, with the application of multiuser detector (MUD). The other method is using the module of MATLAB supporting the GPU with the application of the moving parameter estimation. The test results show that the PSO algorithm based on GPU technology can significantly improve the speed of system capacity, to solve the problem of multi-dimensional global optimization, with the poor real-time performance. It can be widely used in the project of high real-time requirements.

AbstractBoron-doped BaTiO3precurors (BaTi1−xB2xO3+X) were prepared via the glycol-glycerol complexes of boron, titanium (IV), and barium. With optimum composition, ceramics with dielectric properties comparable to those of pristine BaTiO3ceramic sintered at 1300°C can be obtained after sintered at temperature less than 900°C (room-temperature dielectric constant ∼4000, dielectric strength ∼7.0 kV/mm). The appreciable decrease in sintering temperature is attributable to (a) addition of boron dopant as substitute of titamium rather than to stochiometric BaTiO3, and (b) application of glycol-glycerol solvents/ligands in the synthesis of precursors, which guarantees the compositional homogenization of the final ceramics.

The catalytic disproportionation of glycerol was investigated over active carbon (AC) supported catalysts. Typically, 1,2-propanediol, acetic acid, and acetaldehyde were found as the major products of the reaction over catalysts Na2CO3/AC and K2CO3/AC. Other products, such as methanol, ethanol, ethylene glycol, and acetone were also formed as the minor products in the reaction. All of these compounds are defined as oxygenate products (OP). The highest OP yield of 65.3% (carbon mol) was obtained over Na2CO3/AC at 593 K.

A new Eu(III) complex, EuL3(phen), was synthesized, where L is the abbreviation of deprotonated 1-(7-(tert-butyl)-9-ethyl-9H-carbazol-2-yl)-4,4,4-trifluorobutane-1,3-dione(HL), phen is the abbreviation of 1,10-phenanthroline. The Eu(III) complex was characterized by element analysis, IR, 1H NMR, UV-visible absorption spectroscopy, thermogravimetric analysis (TGA), and photoluminescence measurements (PL). TGA shows that thermal stability of the complex is up to 325 °C. PL measurement indicates that the Eu(III) complex exhibits intense red-emission and extends their excitation bands to visible region. LEDs device was successfully fabricated by precoating complex EuL3(phen) onto 460 nm blue-emitting InGaN chip. The emission of device shows that the complex can act as red phosphor in combination with 460 nm blue-emitting chips. This europium complex based on 1-(7-(tert-butyl)-9-ethyl-9H-carbazol-2-yl)-4,4,4-trifluorobutane-1,3-dione is a kind of interesting red-emitting material excited by blue light, which could avoid the damage of excitation by UV light.

The prediction of the indoor radio waves propagation characteristic can be a difficult task because of the indoor environment complexity. Based on the finite difference time domain algorithm, when the monopole antenna is used as the excitation, the indoor radio waves propagation characteristic is researched by using measurment method and simulation method. The effectivity of prediction method is verified by comparing the prediction results with the measurment results. The quantitative research of this paper has certain guiding significance to the confirmation of the wireless digital communication reasonable coverage.