真空微电子器件发展现状及远景了望

本文论述了真空微电子器件的发展远景,并回答了为什么真空微电子器件在未来必将取代固体器件,以及目前它在工艺上和理论上存在些什么困难。     

Janus Nano-Micro Structure-Enabled Coupling of Photothermal Conversion,Heat Localization and Water Supply for High-Efficiency Solar-Driven Interfacial Evaporation

Photothermal conversion, heat localization and water supply are the keys to achieving efficient solar-driven interfacial evaporation. However, effective coupling between the three aspects at the air/liquid interface remains challenging. Herein, Au@Ag-Pd trimetallic nanostructure/polystyrene (PS) microsphere Janus structures are designed as the solar absorber and thermal insulator. The Janus structures deposited on a water supply layer act as a 2D interfacial solar evaporator. The PS microsphere localizes heat at micrometer scale and enhances plasmonic absorption of the Au@Ag-Pd nanocrystals supported on the microsphere. Meanwhile, the Janus structures divide the surface of water supply layer into multiple regions with sub-micrometer depths, lowering the evaporation enthalpy. Owing to the synergic effects of these components, the evaporator realizes a solar-to-vapor conversion efficiency of 99.1% and an evaporation rate of 3.04 kg m⁻² h⁻¹ in pure water under 1 sun illumination. The efficient solar-driven evaporation can last for over 40 h. Furthermore, the solar evaporator shows high-performance seawater desalination with salt removal ratios of near 100%. This study brings new insights for controlling evaporation thermodynamics and kinetics. The Janus nano-micro structure design can be extended to other systems for various solar-thermal applications.     

PEDOT:PSS-CNT Composite Particles Overcome Contact Resistances in Slurry Electrodes for Flow-Electrode Capacitive Deionization

Activated carbon (AC) particles constitute the current material of choice concerning the preparation of flow electrodes for flow-electrode capacitive deionization (FCDI). They are inexpensive, mass-producible, highly conductive, and exhibit a large specific surface area for ion adsorption. However, despite recent advances concerning the modification of AC slurries, their density, and hydrophobicity still constitute major challenges regarding particle aggregation, sedimentation, and pumpability, restricting their particle load to approximately 25 wt.%. Since the particle volume fraction directly correlates to the chance of particle contact, which dictates the charge transfer and hence the degree of flow electrode utilization, the development of AC-based slurries seems to stagnate. This study addresses these challenges by investigating poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)-based suspensions as an alternative to conventional carbon-based flow electrodes. The corresponding conductive hydrogel particles feature softness, internal porosity, low density, hydrophilicity, and a mass-specific salt adsorption capacity that exceeds AC by up to ten times. FCDI experiments can reveal that, contrary to AC, the inherent properties of PEDOT:PSS-based particles simplify the slurry preparation process and enable flow electrode circulation at significantly higher particle volume fractions. These results suggest that PEDOT:PSS-based hydrogel particles are a promising candidate to overcome the percolation and contact-related challenges of state-of-the-art AC slurries.     

Molecular Dynamics Simulations of High-Performance,Dissipationless Desalination across Self-Assembled Amyloid Beta Nanotubes

Climate change is causing droughts and water shortages. Membrane desalination is one of the most widely employed conventional methods of creating a source of clean water, but is a very energy-intensive process. Membrane separation requires high salt selectivity across nano-channels, yet traditional techniques remain inefficient in this regard. Herein, a bioinspired, chemically robust, amyloid–fibril-based nanotube is designed, exhibiting water permeability and salt rejection properties capable of providing highly efficient desalination. Molecular dynamics simulations show that nano-dewetting facilitates the unidirectional motion of water molecules on the surface of amyloid beta (Aβ) sheets owing to the ratchet structure of the underlying potential surface and the broken detailed balance. The water inside the self-assembled Aβ nanotube (ABNT) overflows, while the passage of salts can be blocked using amphiphilic peptides. The designed nanofilter ABNT shows 100% desalination efficiency with perfect NaCl rejection. The production of ≈2.5 tons of pure water per day without any energy input, which corresponds to a water flux up to 200 times higher than those of existing commercial methods, is assessed by this simulation method. These results provide a detailed fundamental understanding of potential high-performance nanotechnologies for water treatment.     

Structural/Compositional-Tailoring of Nickel Hexacyanoferrate Electrodes for Highly Efficient Capacitive Deionization

Prussian blue analogs (PBAs) represent a crucial class of intercalation electrode materials for electrochemical water desalination. It is shown here that structural/compositional tailoring of PBAs, the nickel hexacyanoferrate (NiHCF) electrodes in particular, can efficiently modulate their capacitive deionization (CDI) performance (e.g., desalination capacity, cyclability, selectivity, etc.). Both the desalination capacity and the cyclability of NiHCF electrodes are highly dependent on their structural/compositional features such as crystallinity, morphology, hierarchy, and coatings. It is demonstrated that the CDI cell with hierarchically structured NiHCF nanoframe (NiHCF-NF) electrode exhibits a superior desalination capacity of 121.38 mg g⁻¹, a high charge efficiency of up to 82%, and a large capacity retention of 88% after 40 cycles intercalation/deintercalation. In addition, it is discovered that coating of carbon (C) film over NiHCF can lower its desalination capacity owing to the partial blockage of diffusion openings by the coated C film. Moreover, the hierarchical NiHCF-NF electrode also demonstrates a superior selectivity toward monovalent sodium ions (Na⁺) over divalent calcium (Ca²⁺) and magnesim (Mg²⁺) ions, allowing it to be a promising platform for preferential capturing Na⁺ ions from brines. Overall, the structural/compositional tailoring strategies would offer a viable option for the rational design of other intercalation electrode materials applied in CDI techniques.     

固定床离子交换树脂复苏方法探讨

为了提高脱盐水水质 ,降低系统的腐蚀和结垢 ,本文通过实验方法对污染较严重的树脂进行复苏 ,从而达到提高树脂的工作交换容量和再生程度     

HNF-130型CTA中空纤维纳滤组件的研制

本文介绍了HNF-130型CTA中空纤维纳滤组件的制备工艺和技术性能,并考察了不同操作条件对组件的产水量、脱除率的影响。     

Effect of inclination of external flat plate reflector of basin type still in winter

This paper presents a theoretical analysis of a basin type solar still with an internal reflector (two sides and back walls) and an inclined flat plate external reflector on a winter solstice day at 30° N latitude. We are proposing a new geometrical method for calculating the solar radiation reflected by the inclined external reflector and then absorbed on the basin liner. Using this method, we performed a numerical analysis of heat and mass transfer in the still in order to determine the effectiveness of the inclination of the external reflector. We found that the benefit of a vertical external reflector would be smaller or even negligible for a still with a larger value for the glass cover angle, while an inclined external reflector can increase the distillate productivity of the still at any glass cover angle, and the external reflector angle should be set at about 15° from vertical on a winter solstice day. The daily amount of distillate of the still with the inclined external reflector would be about 16% greater than that with the vertical external reflector, and about 2.3 times as large as that of the still with neither the internal nor the external reflector on a winter solstice day.     

Some criteria to minimize the impact of brine dischargeinto the sea

On a uniformly sloping beach, high salinity build-up along the coast associated with brine discharge into the sea can be avoided by building a longer outfall. For an existing seawater desalination plant, extending the outfall will affect the design specification of the plant. Using a two-dimensional advection-diffusion equation, model solutions that can minimize the shoreline salinity levels without building a longer sea outfall are presented.     

Saltbush (Atriplex lampa) leaf protein concentrate by ultrafiltration for use in balanced animal feed formulations

The purpose of this study was to evaluate the use of ultrafiltration and discontinuous diafiltration (DD) to obtain a protein concentrate from Atriplex lampa saltbush, improving its palatability by decreasing the salt content (mainly sodium and potassium chloride). The experimental work was done using a Pellicon^® cassette (25 units) system equipped with polyethersulfone organic membranes with a molecular weight cut‐off value of 10 kD. The characteristic of the membranes and the feed material, the parameters and operational conditions were studied in the pretreatment of the sample as well as in the ultrafiltration process to obtain a maximum performance. The product obtained contained 85% protein on aa dry weight basis and a marked decrease in salt content, from 40% in fresh leaves to 2.5% after processing by DD, which is in agreement with the average conductivity values observed, from 18.1 mS cm^?1 in the initial aqueous alkaline extract to a final value of 3.5 mS cm^?1. Measurements of normalized water permeability were determined after each wash cycle in order to verify the flow recovery through the membrane. Analysis of amino acids from the protein concentrate with a chemical score of 85.13 was calculated using a Food Agricultural Organization reference pattern (sulfur amino acids as limiting amino acids). Nitrogen retention was evaluated by means of a biological test and the following values were obtained: net protein utilization = 63.00 ± 4.00, true digestibility = 79.00 ± 5.21, and biological value = 79.80. The presence of oxalic acid, nitrates, saponins, phenolic compounds and condensate tannins is not significant. The results indicate that the concentrate obtained has a high content of lysine, making these products particularly useful as a complement for cereal flour, which is deficient in this amino acid. The determined values suggest that the product can be used in balanced animal feed formulation. Copyright © 2007 Society of Chemical Industry