Template Conversion Research Articles

Thermally Annealed High-Aspect-Ratio ZIF-8 Nanoplates-Incorporated Mixed Matrix Membranes for Improved H2/CO2 Selectivity.

The main challenge in the preparation of MOF-based mixed matrix membranes is to construct a good interface morphology to improve the gas separation performance and stability of the membranes. Herein, high-aspect-ratio ZIF-8 nanoplates for H2/CO2 separation membranes were synthesized by direct template conversion. The ZIF-8 nanoplates were prepared with the commercial Matrimid polymer to form MMMs by the flat scraping method. The homogeneous dispersion of high-aspect-ratio nanoplates in the membrane and the good compatibility between the filler and the matrix caused by the thermal annealing operation improve the gas separation performance and mechanical properties of MMMs. The H2/CO2 selectivity of MMMs loaded with 30 wt % ZIF-8 nanoplates increased to 10.3, and the H2 permeability was 330.1 Barrer. This synthesis method can be extended to prepare various ZIF nanoplates with elevated aspect ratios to obtain excellent performance fillers for gas separation of MMMs. In addition, the thermal annealing operation allows more efficient gas separation in polymer membranes and is a feasible way to design excellent and stable MMMs.

Intelligent System of Art Design Based on Cloud Sharing Internet New Media System

Through the real-time template conversion mechanism, the system will automatically collect and filter the Internet site content in a way that conforms to the user experience of the TV screen. Virtualization and cloud computing technology take Internet technology as the main operating platform and are closely linked with Internet technology in the development. It focuses on the construction strategy of higher art and design education system in the new media era, covering the current situation of art and design education system, information technology and art design In-depth integration, development of each student's own advantages and specialties, broadening the contact surface of new media art design with the outside world, so that the discipline develops towards a richer and more diversified trend.

Two-dimensional basic cobalt carbonate supported ZIF-67 composites towards mixed matrix membranes for efficient CO2/N2 separation

Two-dimensional (2D) porous materials have great potential in high-performance gas separation membranes. Herein, we demonstrate a facile synthesis of basic cobalt carbonate supported zeolitic imidazolate framework-67 (BCoC-ZIF) nanoplates via a template conversion method in aqueous solutions. Basic cobalt carbonate nanosheets were used as the metal source and BCoC-ZIF composites with various ZIF-67 loadings were obtained through adjusting the reaction time in an aqueous solution of 2-methylimidazole. Numerous mixed matrix membranes (MMMs) are prepared with different loadings of BCoC-ZIF composite nanoplates in the polymer of intrinsic porosity-1 (PIM-1), ranging from 1 to 20 wt% of filler loadings. The typical MMM with 10 wt% loading shows a CO2 permeability of 7326 Barrer and CO2/N2 separation factor of 32.5, exceeding the latest 2019 upper bound. The improved separation performance greatly relies on the multiply synergistic effect of high CO2 adsorption capacity, alignment of 2D morphology and molecular sieving ability of BCoC-ZIF. This study may offer a new direction for the rational design of MMMs for gas separation applications.

Morphology-controllable synthesis of hierarchical hollow GaFeO3 microcubes with selective triethylamine gas-sensing properties

Hierarchical multi-metal oxide-based gas sensors with high surface area and abundant active sites have attracted intensely research interests for their highly sensitive and fast gas detection performance. Developing synthetic strategies for obtaining novel hierarchical metal oxides with high sensing performance remains eminently challenging. Herein, hierarchial hollow GaFeO3 microcubes were successfully prepared via a Ga3+-modified Fe-based Prussian Blue (PB) mediated template conversion strategy. The microsized morphologies and hollow interior structures of GaFeO3 microcubes can be feasibly modulated by controlling the thermolysis temperatures. The ultrasmall nanoparticle-assembly of GaFeO3 architecture obtained at 500 °C exhibited an optimum response value (Ra/Rg) of 7.4, and rapid response/recovery times (9 s/49 s) toward 200 ppm triethylamine (TEA) at a working temperature of 200 °C, as well as remarkable selectivity and excellent long-term stability (for at least 31 days), which are intrinsically beneficial from the unique interior loose structure with good permeability for diffusion of target gases. This work provides a promising approach for synthesizing various hierarchical multimetal oxides with intriguing nanoparticle-assembled hollow structure and broad prospects for practical gas sensing applications.

High-aspect ratio zeolitic imidazolate framework (ZIF) nanoplates for hydrocarbon separation membranes.

Metal-organic frameworks with high aspect ratios have the potential to yield high-performance gas separation membranes. We demonstrate the scalable synthesis of high–aspect ratio zeolitic imidazolate framework (ZIF)–8 nanoplates via a direct template conversion method in which high aspect ratio–layered Zn hydroxide sheets [Zn5(NO3)2(OH)8] were used as the sacrificial precursor. Successful phase conversion occurs as a result of the collaboration of low template stability and delayed delivery of 2-methylimidazole in weakly interacting solvents, particularly using acetone. When the ZIF-8 nanoplates with an average aspect ratio of 20 were shear aligned in the 6FDA-DAM polymer matrix by bar coating, the separation performance for propylene/propane far surpassed that of the previously reported mixed matrix and polymeric membranes, showing a propylene permeability of 164 Barrer and selectivity of 33.4 at 40 weight % loadings.

Nanosheet-assembled, hollowed-out hierarchical γ-Fe2O3 microrods for high-performance gas sensing

Nanosheet-assembled, hollowed-out hierarchical γ-Fe2O3 microrods for ultrahigh-sensitive and fast response acetone detection were constructed through a MgO-mediated template conversion strategy.

Template synthesis of cobalt molybdenum sulfide hollow nanoboxes as enhanced bifunctional Pt-free electrocatalysts for dye-sensitized solar cells and alkaline hydrogen evolution

Due to the unique features including well-defined void space and high surface-to-volume ratio, non-noble metal catalysts with hollow structures have received intensive researches in dye-sensitized solar cells (DSSCs) and electrochemical water splitting. Herein, we prepare a series of cobalt-incorporated molybdenum sulfide hollow nanoboxes (denoted as Co-MoSx NBs) via a one-step fleet template conversion from cube-shaped Co-based zeolitic imidazolate framework-67 which precipitated without prolonged aged process. During above transformation, it is notable that the surface morphologies of nanobox can be effectively tailored by the proportion of MoS42−. The as-obtained Co-MoSx NBs with well-defined boxed structure and the appropriate doped ratio are developed as bifunctional catalysts for accelerating both reduction of I3− in DSSCs and hydrogen evolution reaction (HER). As expected, a high power conversion efficiency (9.64%) is achieved by Co-MoSx-1/3 NBs based DSSC under AM 1.5G irradiation, which is much preceded to that of Pt (8.39%). Meanwhile, the practical utilization of Co-MoSx-1/3 NBs for HER yields a low onset overpotential (35 mV) and a small Tafel slope (61.4 mV decade−1) in alkaline medium.

Template Conversion of Covalent Organic Frameworks into 2D Conducting Nanocarbons for Catalyzing Oxygen Reduction Reaction.

Progress over the past decades in porous materials has exerted great effect on the design of metal-free carbon electrochemical catalysts in fuel cells. The carbon material must combine three functions, i.e., electrical conductivity for electron transport, optimal pores for ion motion, and abundant heteroatom sites for catalysis. Here, an ideal carbon catalyst is achieved by combining two strategies-the use of a 2D covalent organic framework (COF) and the development of a suitable template to guide the pyrolysis. The COF produces nanosized carbon sheets that combine high conductivity, hierarchical porosity, and abundant heteroatom catalytic edges. The catalysts achieve superior performance to authentic Pt/C with exceptional onset potential (0 V vs -0.03 V), half-wave potentials (-0.11 V vs -0.16 V), high limit current density (7.2 mA cm-2 vs 6.0 mA cm-2 ), low Tafel slope (110 mV decade-1 vs 121 mV decade-1 ), long-time stability, and methanol tolerance. These results reveal a novel material platform based on 2D COFs for designing novel 2D carbon materials.

Development of lead iodide perovskite solar cells using three-dimensional titanium dioxide nanowire architectures.

Three-dimensional (3D) nanowire (NW) architectures are considered as superior electrode design for photovoltaic devices compared to NWs or nanoparticle systems in terms of improved large surface area and charge transport properties. In this paper, we report development of lead iodide perovskite solar cells based on a novel 3D TiO2 NW architectures. The 3D TiO2 nanostructure was synthesized via surface-reaction-limited pulsed chemical vapor deposition (SPCVD) technique that also implemented the Kirkendall effect for complete ZnO NW template conversion. It was found that the film thickness of 3D TiO2 can significantly influence the photovoltaic performance. Short-circuit current increased with the TiO2 length, while open-circuit voltage and fill factor decreased with the length. The highest power conversion efficiency (PCE) of 9.0% was achieved with ∼ 600 nm long 3D TiO2 NW structures. Compared to other 1D nanostructure arrays (TiO2 nanotubes, TiO2-coated ZnO NWs and ZnO NWs), 3D TiO2 NW architecture was able to achieve larger amounts of perovskite loading, enhanced light harvesting efficiency, and increased electron-transport property. Therefore, its PCE is 1.5, 2.3, and 2.8 times higher than those of TiO2 nanotubes, TiO2-coated ZnO NWs, and ZnO NWs, respectively. The unique morphological advantages, together with the largely suppressed hysteresis effect, make 3D hierarchical TiO2 a promising electrode selection in designing high-performance perovskite solar cells.

Synthetic prions and other human neurodegenerative proteinopathies

Transmissible spongiform encephalopathies (TSE) are a heterogeneous group of neurodegenerative disorders. The common feature of these diseases is the pathological conversion of the normal cellular prion protein (PrPC) into a β-structure-rich conformer-termed PrPSc. The latter can induce a self-perpetuating process leading to amplification and spreading of pathological protein assemblies. Much evidence suggests that PrPSc itself is able to recruit and misfold PrPC into the pathological conformation. Recent data have shown that recombinant PrPC can be misfolded in vitro and the resulting synthetic conformers are able to induce the conversion of PrPC into PrPScin vivo. In this review we describe the state-of-the-art of the body of literature in this field. In addition, we describe a cell-based assay to test synthetic prions in cells, providing further evidence that synthetic amyloids are able to template conversion of PrP into prion inclusions. Studying prions might help to understand the pathological mechanisms governing other neurodegenerative diseases. Aggregation and deposition of misfolded proteins is a common feature of several neurodegenerative disorders, such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis and other disorders. Although the proteins implicated in each of these diseases differ, they share a common prion mechanism. Recombinant proteins are able to aggregate in vitro into β-rich amyloid fibrils, sharing some features of the aggregates found in the brain. Several studies have reported that intracerebral inoculation of synthetic aggregates lead to unique pathology, which spread progressively to distal brain regions and reduced survival time in animals. Here, we review the prion-like features of different proteins involved in neurodegenerative disorders, such as α-synuclein, superoxide dismutase-1, amyloid-β and tau.

An Efficient Software Clone Detection System based on the Textual Comparison of Dynamic Methods and Metrics Computation

clone is a kind of software recycling that has a greater influence on the maintenance of huge software systems. The business services are provided by web applications that employ a combination of page design and language code scripting. Usually, code redundancy in applications result from copy and paste practices called code clones. Searching for software clones is the key objective of this research. The clone identification procedure which is introduced in this paper is a hybrid approach that depends on template conversion and metrics comparison. There are four phases involved in the proposed scheme, namely, input and pre-processing, template conversion, metrics computation and clone type detection. File integration, elimination of white noise and statement normalization are the steps involved in the pre-processing stage. The metrics that are calculated includes numerous lines of code, arguments, looping statements, return statements and conditional statements. The pairs that have identical characteristics during textual evaluation are termed as the clones. This method of clone detection seems to be less complex with better accuracy and efficiency in contrast to other existing methods. The performance analysis is made against the prevailing systems to show efficiency improvement obtained through this method. The implementations are carried out with the help of JAVA. Keywordsdetection, Template conversion, Metrics computation, File integration, Normalization.

Effect of template conversion from the B to the Z conformation on RNA polymerase activity.

Transition from the right-handed B to the left-handed Z conformation of DNA was studied by circular dichroism in parallel with the ability of the DNA to support RNA synthesis with Escherichia coli RNA polymerase. Since the B to Z transition is generally induced by a chemical agent, a definitive demonstration that a change in activity is due to the conformational change, and not to the agent itself or to other factors, requires the clear-cut correlation of template activity and conformation under a variety of conditions that result in conformational change. Such correlation was achieved by following the [Co(NH3)6]3+-induced transition of poly(dG-dC) X poly(dG-dC) and poly(dG-dm5C) X poly(dG-dm5C) and the Mg2+-induced transition of poly(dG-dm5C) X poly(dG-dm5C). In addition, conditions were chosen to minimize possible aggregation. In each of these three systems, the B to Z conformational transition was accompanied by a substantial decrease in transcription activity. While the conversion from B to Z of poly(dG-dm5C) X poly(dG-dm5C) is induced by a 25-fold lower concentration of [Co(NH3)6]3+ than that required for the conversion of unmethylated polymer, in both cases the RNA polymerase activity is decreased at the same cation concentration as that producing the conformational transition. Neither [Co(NH3)6]3+ nor Mg2+ inhibits RNA synthesis with control templates that are not converted to Z under the same conditions, such as poly(dA-dT) X poly(dA-dT) or calf thymus DNA with [Co(NH3)6]3+ or poly(dG-dC) X poly(dG-dC) with Mg2+.(ABSTRACT TRUNCATED AT 250 WORDS)