61 results match your criteria: "Beijing University of Technology Beijing 100124 China.[Affiliation]"

Biomass holds significant potential for large-scale synthesis of hard carbon (HC), and HC is seen as the most promising anode material for sodium-ion batteries (SIBs). However, designing a HC anode with a rich pore structure, moderate graphitization and synthesis through a simple process using a cost-effective precursor to advance SIBs has long been a formidable challenge. This is primarily because high temperatures necessary for pore regulation invariably lead to excessive graphitization.

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  • This text discusses how activating chemical bonds at less negative voltages can enhance functional group tolerance and selectivity in organic electrosynthesis.
  • Researchers developed a method that combines electro-reduction with hydrogen bonding to make chemical reactions more efficient.
  • A specific example showed that they could improve the reduction potential of a compound and perform a complex reaction without needing extra radical sources or prep steps, using a special ionic liquid for the process.
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  • Glass microfluidic chips are advantageous for mass spectrometry due to their design and resistance to chemicals, but creating a nanospray ionization emitter in glass is challenging.
  • A new method using continuous fluid-assisted etching has been developed to produce sharp 3D nESI emitters within the chips, allowing for efficient integration.
  • The system successfully detects neurochemicals in tiny droplets and shows promise for future applications in neurochemical monitoring and single-cell analysis.
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Ultrafiltration (UF) is a high-potential technology for purifying natural surface water; however, the problem of membrane fouling has limited its widespread application. Herein, ultraviolet (UV)-activated ferrate (Fe(vi)) was used to purify natural surface water and improve the performance of the UF membrane. The combination of UV and Fe(vi) could generate active species (Fe(v), Fe(iv), ˙OH and O˙) to degrade pollutants, while the produced Fe(iii) had the effect of coagulation.

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In experiments, printing paper is imprinted with three different ink micropatterns (square, grid, and stripe). The wetting contact angle of water droplets on a heterogeneous surface is then investigated using a proportionate scaling molecular dynamics (MD) simulation, where the water droplets and the ink-patterned printing paper are both shrunk by a factor of 200 000 collectively. The errors from the theoretical values are always less than 1°, which is much less than the bias of experimental measurement data, according to the modeling contact angles.

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A two-terminal (2T) perovskite/silicon heterojunction tandem solar cell (PVSK/SHJ) is considered one of the most promising candidates for next-generation photovoltaics with the possibility of achieving a power conversion efficiency (PCE) exceeding 30% at low production cost. However, the current mismatch and voltage loss have seriously decreased the performance of 2T PVSK/SHJ tandem solar cells. Here, we report the composition engineering for perovskite top cells to prepare a high performance 2T tandem cell by tuning CsBr co-evaporating rates and increasing concentrations of FAI/FABr solutions.

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Fe-N-C has a high number of FeN active sites and has thus been regarded as a high-performance oxygen reduction reaction (ORR) catalyst, and combining FeC with Fe-N-C typically boosts ORR activity. However, the catalytic mechanism remains unknown, limiting further research and development. In this study, a precipitation-solvothermal process was used in conjunction with pyrolysis to produce a series of Fe-N-C catalysts derived from a zeolitic imidazolate framework (ZIF) that was composited with FeC.

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Dielectrics of the polymer-matrix composite are considered to present combined advantages from both the polymer matrix and inorganic fillers. However, the breakdown strength, as well as energy density, is not effectively enhanced due to the poor compatibility between the organic and inorganic components. Herein, polymer composites derived from polystyrene (PS) and barium titanate (BTO) are proposed and beneficial interface modification by poly(styrene--maleic anhydride) (PS--mah) is conducted to improve compatibility between the inorganic filler and polymer matrix.

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When the power conversion efficiency (PCE) of perovskite solar cells (PSCs) rapidly approaches that of commercial solar cells, the stability becomes the most important obstacle for the commercialization of PSCs. Aside from the widely studied slow PCE degradation, the PSCs also show a unique rapid PCE degradation. Although the degradation due to oxygen and humidity can be avoided by encapsulation, that due to bias voltage, light and heat could not be effective suppressed and will lead to considerable degradation.

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An all-optical tunable whispering gallery mode (WGM) laser pumped by a laser diode is proposed. The laser is fabricated by filling a silica capillary with a light-emitting conjugated polymer solution. Based on the thermo-optic effect of the hydroxyl groups in the polymer and capillary, the effective refractive index of the WGM cavity changes by the auxiliary irradiation of the laser, and the wavelength of the WGM mode shifts correspondingly.

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Article Synopsis
  • Surface-enhanced Raman scattering (SERS) technology is highly effective for detecting small amounts of molecules in liquids, especially when using 3D SERS-active platforms.
  • A new platform involving a silver-coated capillary was developed for enhanced SERS detection, utilizing a silver mirror reaction for coating and PDMS for film protection.
  • The system demonstrated a significant enhancement factor and a low detection limit for rhodamine 6G, showing high SERS intensity uniformity and potential for future optofluidic systems.
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From the perspective of crystallography, there exist crystals as well as boundary planes in NdFeB permanent magnets and accordingly, there should exist orientation textures of NdFeB crystals and orientation texture of boundary planes. This work therefore aims to study the misorientations across boundary planes in a sintered NdFeB permanent magnet. As an interdisciplinary study, serial stereological methods are developed to extract more structural information from the material and as the result, spreading wetting and penetration of Nd-Rich phases to the NdFeB phase are quantificationally characterized.

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Flexible perovskite solar cells (PSCs) have attracted tremendous attention due to their potential application in portable and wearable electronics. However, the photoelectric conversion efficiency (PCE) of flexible PSCs is still far lower than that of usual rigid PSCs. Moreover, the mechanical stability of flexible PSCs cannot meet the needs of commercial applications because of the cracking of perovskite grains caused by bending stress.

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A novel and amplifying anaerobic electrochemical membrane bioreactor (AnEMBR, R2) was constructed and operated for a long time (204 days) with synthetic glucose solution having an average chemical oxygen demand (COD) of 315 mg L, at different applied voltages and room temperatures. More than twice sodium bicarbonate was added for maintaining a pH of around 6.7 in the supernatant of the reactor R2, close to that of a control reactor called anaerobic membrane bioreactor (AnMBR, R1), after 138 days.

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The separation of molybdenum (Mo) from tungstate solution is a bottleneck problem in tungsten (W) metallurgy, and it hinders the development of high-purity tungsten materials. In this research, a modified D301 resin was used to adsorb and separate molybdenum from tungstate solution. The maximum sorption capacity ( ) of modified D301 for MoS was found to be 428 mg g and the separation coefficient () was 108.

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Methylamine (CHNH, MA) gas-induced fabrication of organometal CHNHPbI based perovskite thin films are promising photovoltaic materials that transform the energy from absorbed sunlight into electrical power. Unfortunately, the low stability of the perovskites poses a serious hindrance for further development, compared to conventional inorganic materials. The solid-state perovskites are liquefied and recrystallized from CHNH.

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Nanoprecursors used as a structural promoter (SP) were prepared by a hydrothermal method and named sol-SP. After centrifugation, the supernatant and precipitate were denoted as solution-SP and solid-SP, respectively. The effect of the additive amount on the structures and properties of the synthesized clinoptilolite was investigated using various characterization techniques.

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In the past few years, metal-organic frameworks (MOFs) have emerged as a class of fascinating materials for photocatalysis. Herein, a new MOF formulated as [Zn(bpe)(fdc)]·2DMF (BUT-206, bpe = 1,2-bis(4-pyridyl) ethylene, Hfdc = 2,5-furan dicarboxylic acid, DMF = ,-dimethylformamide) is reported, which was synthesized under solvothermal conditions and applied for photocatalytic degradation of dyes (crystal violet and rhodamine B). Noteworthily, BUT-206 exhibited high photocatalytic activity toward the degradation of crystal violet without using any photosensitizer or cocatalyst under UV-irradiation.

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Three kinds of the bipyridine-proline chiral ligands as highly active species were successfully introduced on Zn-modified mesoporous silica nanomaterials (BMMs, MCM-41, and SBA-15) the covalent attachment and coordination methods. Their microstructural features and physicochemical properties were extensively characterized XRD patterns, SEM/TEM images, TGA profiles, FT-IR and UV-Vis spectra. In particular, their fractal features, the pair distance distribution function, and the Porod plots were evaluated thoroughly on the basis of the SAXS data.

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Understanding the active sites of Fe-N-C materials and their properties in the ORR catalysis system.

RSC Adv

March 2022

Beijing Key Laboratory for Catalysis and Separation, Department of Environment and Chemical Engineering, Beijing University of Technology Beijing 100124 China

Metal-N-C-based catalysts prepared by pyrolysis are frequently used in the oxygen reduction reaction (ORR). Zeolitic imidazolate frameworks (ZIFs), a type of metal organic framework (MOF), are selected as precursors due to their special structure and proper pore sizes. A series of Fe-N-C catalysts with different concentrations of 2-methylimidazole were prepared with a simple solvothermal-pyrolysis method, and the transformation productivity, morphology and ORR activity were investigated.

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Visually precise, low-damage, single-cell spatial manipulation with single-pixel resolution.

Chem Sci

February 2021

Center of Excellence for Environmental Safety and Biological Effects, Beijing Key Laboratory for Green Catalysis and Separation, Department of Chemistry and Biology, Beijing University of Technology Beijing 100124 China

The analysis of single living cells, including intracellular delivery and extraction, is essential for monitoring their dynamic biochemical processes and exploring intracellular heterogeneity. However, owing to the 2D view in bright-field microscopy and optical distortions caused by the cell shape and the variation in the refractive index both inside and around the cells, achieving spatially undistorted imaging for high-precision manipulation within a cell is challenging. Here, an accurate and visual system is developed for single-cell spatial manipulation by correcting the aberration for simultaneous bright-field triple-view imaging.

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We report a set of electrochemically regulated protocols for the divergent synthesis of ketones and β-keto esters from the same β-hydroxycarboxylic acid starting materials. Enabled by electrochemical control, the anodic oxidation of carboxylic acids proceeded in either a one-electron or a two-electron pathway, leading to a 1,4-aryl transfer or a semipinacol-type 1,2-group transfer product with excellent chemoselectivity. The 1,4-aryl transfer represents an unprecedented example of carbon-to-oxygen group transfer proceeding a radical mechanism.

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Ultrafast optical switch based on plasmonic nanostructures has large application potentials in optical logic circuits and optical communication systems. Integration of plasmonic optical switching devices with optical fibers is a breakthrough for realizing practical applications in long-range optical data transmission or communication techniques. Here, the incorporation of plasmonic optical switch devices onto the end facets of optical fibers is reported, so that the switched optical signals are generated by interaction between femtosecond laser pulses and plasmonic nanostructures on one end of the fiber, and are delivered via the fiber waveguide to the other end for detection or decoding.

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The development of Surface Enhanced Raman Scattering (SERS) promotes the wide application of Raman spectroscopy in chemical and biomolecular detection. SERS detection relies on analytes in close contact with the metallic surface, and therefore direct molecular trace detection in the liquid phase is difficult. In this paper, static liquid phase SERS detection was performed simply using a capillary without pre-functionalization.

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Electric field-assisted fused deposition modeling (E-FDM) is a promising technique in the field of 3D printing. This paper studies the start-up stage of the printing, which is a process of liquid gradually deforming and making an initial contact with the substrate under the action of electric stress. Polycaprolactone, a popular material for biomedicine, is selected as the printing material.

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