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Corrosion is one of the key technical challenges affecting the large-scale application of magnesium and its alloys.Superhydrophobic surfaces are an effective way to improve the corrosion resistance of magnesium alloys，as they can effectively isolate direct contact between the metal substrate from the corrosive medium，thereby reducing the corrosion rate.A superhydrophobic film composed of Copper-Metal Organic Framework-Stearic Acid (Cu-MOF-SA) was successfully fabricated on an AZ31 magnesium alloy substrate using a one-step electrodeposition method.Comprehensive studies were conducted on the corrosion resistance，chemical stability and thermal stability of the superhydrophobic film.Results showed that the water contact angle of the superhydrophobic film surface reached up to 158°；the sample coated by superhydrophobic film exhibited good corrosion resistance in a 3.5%NaCl solution.Compared with the AZ31 magnesium substrate，the corrosion potential of the superhydrophobic film increased by 0.24 V，and the corrosion current density was reduced by one order of magnitude.The water contact angle of the superhydrophobic film remained larger than 135° after being immersed in solutions with a pH of 1～14 for 24 h.The corrosion potential of superhydrophobic film after being immersed in solution with a pH of 1 for 24 h was 0.21 V higher than that of the AZ31 magnesium substrate.After being insulated in air at 20 ～90 ℃for 24 h，the water contact angle of the Cu-MOF-SA superhydrophobic film’s surface remained above 154°.Additionally，after being insulated in air at 80 ℃for 24 h，the corrosion potential of the superhydrophobic film was 0.22 V higher than that of the AZ31 magnesium substrate.The corrosion current density of the superhydrophobic film was one order of magnitude smaller than that of AZ31 magnesium alloy substrate.In brief，the Cu-MOF-SA superhydrophobic film fabricated in this study demonstrated excellent superhydrophobicity and corrosion resistance.

Trilobatin is a flavonoid that has wide application prospects due to its various pharmacological effects, such as anti-inflammation and anti-oxidation. In this work, a novel electrochemical sensor based on gold nanobipyramids (AuNBs) and L -cysteine (L -cys) was constructed for the sensitive and selective determination of trilobatin. The AuNBs, which were prepared by a seed-mediated growth method, had large specific surface areas and excellent electrical conductivity. A layer of L -cys film, which provided more active sites through the amino and hydroxyl groups, was modified on the surface of the AuNBs by electropolymerization. Significantly, the Au–S bond between the L -cys film and AuNBs could improve the stability of the sensor and it exhibited satisfactory electrocatalytic oxidation activity for trilobatin. Under optimized conditions, the sensor based on poly- L -cys/AuNBs/GCE was used to determine trilobatin by differential pulse voltammetry (DPV). Two wide linear ranges between the current peak and the concentration of trilobatin were obtained in the range from 5 to 100 μM and 100 to 1000 μM, and the low detection limit (LOD) was up to 2.55 μM (S/N = 3). The sensor demonstrated desirable reproducibility, stability, and selectivity and was applied to detect real trilobatin samples extracted from Lithocarpus polystachyus Rehd.'s leaves, showing recoveries of 98.36%–104.96%, with satisfactory results. [ABSTRACT FROM AUTHOR]

In a spectroholographic storage system the defocusing method is often used to obtain spectrum uniformity and improve the quality of the recorded information. However, defocusing introduces vignette and stronger interpixel cross talk in the marginal field of view. We report a method that defocuses the aperture and medium together. Based on the pixel spread function, two inequalities are introduced to estimate the upper and lower bounds of the energy received at the CCD. We balance the spectrum uniformity with interpixel cross talk and vignette and then allow the designer to select optimal structure values of the defocusing spectroholographic storage system, i.e., the defocusing value, aperture size, and fill factors for the spatial light modulator and CCD. OCIS codes: 210.2860, 110.0110.

In spectroholographic storage systems the defocusing method is often used for spectrum uniformity and quality improvement of recorded information. The same purpose is served by the fractional Fourier transform (FRFT) storage system. To simplify the numerical analysis, we derive the expressions of the Fraunhofer spectrum and the reconstructed image at the detected plane (CCD) for both cases instead of using the Fresnel spectrum and the FRFT spectrum. The recording aperture, spectrum uniformity, and reconstructed information of both systems are investigated. A numerical comparison is also presented. OCIS codes: 210.2860, 070.0070, 210.0210.

A nonuniform photovoltaic field is created in Fe:LiNb[O.sub.3] during hologram recording exposures. Experimental results and analysis show the degradation of the volume holograms in the presence of the quality. Experimental results to demonstrate the effectiveness of the proposed method are presented. OCIS codes: 090.4220, 090.7330.

A spatial-encoding scheme for the one-step implementation of the optical hit-miss transform (HMT) is presented. The rank-order HMT, which yields better performance in the presence of noise and clutter, can also be carried out by the use of this scheme. Numerical simulations and experimental results have proved the scheme to be feasible. Key words: Hit-miss transform, optical pattern recognition, optical correlation.

A photorefractive optical processor that uses complementary encoding is presented for the real-time implementation of truth-table lookup. Recording a multiexposure hologram in a photorefractive crystal permits different truth-table patterns to be stored. The processor is capable of performing the functions of fall addition, half-addition, subtraction, multiplication, and the calculation of complex multinominal with any number system. Key words: Optical computing, truth-table lookup, photorefractive crystal.

We describe a joint wavelet-transform correlator in which the wavelet function is combined with the input image as the input joint image to realize the wavelet transform of the objective image. The Haar wavelet and the Roberts filter are chosen as the wavelet functions to extract the features of the objective image. The relationship of the Haar wavelet and the Roberts filter is analyzed mathematically based on admissible condition of the wavelet. Computer simulations are provided to verify the theory and to illustrate the performance of this correlator. Key words: Wavelet transform, joint transform correlator, feature extraction.

Formaldehyde is one of the mostly used reductants in electroless copper. Silver ions were introduced into the plating bath to improve the plating rates and the film ductility. The linear scan voltammetry was used to study the influence of silver ions on the reduction behavior of copper, which indicates that the silver ions were co‐reduced with copper. The incorporation of silver increased copper deposition rate. The plating rate increased from 17 μm h−1 in the silver‐free solution to 29 μm h−1 as 25 mg L−1 Ag2SO4 was added. Folding tests were performed to illustrate the effect of silver on film ductility. The addition of silver ions in the plating baths improved the folding endurance of copper layers. The stability of the plating bath containing 20 mg L−1 Ag2SO4 was investigated using UV/Vis absorption spectroscopy. The bath was stable for at least 2 weeks. [ABSTRACT FROM AUTHOR]

A chemical cleaving method to improve the resolution of relief modulation in dichromated gelatin is presented. The process (which uses hydroxylamine) yields higher relief resolution and better profile fidelity than a process that uses the enzyme trypsin because it has many fewer cleaving sites. Experiments prove that relief modulation can produce a resolution of as much as 500 lines/mm. With a projection exposure system, a microprism array with a 30-[micro]m-wide, 0.8-[micro]m-high cell is fabricated by this method. A method for forming a continuous relief on dichromated gelatin is also discussed. [C] 2000 Optical Society of America OCIS codes: 000.1570, 050.1970, 160.4670, 220.3740, 230.4000.

The copper films that electroless plated from the formaldehyde‐based solutions frequently suffer from the internal stress. The internal stress leads to a poor ductility of the plated films. To lower internal stress and improve ductility of copper films, sodium hydroxyethyl sulfonate was used as a surfactant to promote the detachment of hydrogen bubbles. The folding tests showed that the copper film deposited from the solution containing 3 mL L−1 25% sodium hydroxyethyl sulfonate (EHS) had the best ductility. The internal stresses of the copper films were measured using X‐ray diffraction technique and the stress decreased from 100 MPa to 30 MPa as the EHS concentration increased from 0 to 3 mL L−1. Sodium hydroxyethyl sulfonate had little influence on the film morphology and crystal size. High plating rates (> 8 μm h−1) were obtained from the solution containing sodium hydroxyethyl sulfonate. [ABSTRACT FROM AUTHOR]

Manganese oxide was deposited from a non-aqueous solution, dimethyl sulfoxide (DMSO), via the reduction of dissolved oxygen. The formed superoxide radical ion (O2−Ṗ) reacts rapidly with the manganese ions forming a smooth and thin film (80 nm) of manganese oxide. From an in situ EQCM study, it could be concluded that MnO2 was the most probable oxide which was deposited at an average growth rate of 0.049 μg s−1 or 0.077 nm s−1. Since the direct deposition of a phase pure MnO2 layer was not confirmed by XRD, it is more likely that a variety of manganese oxides has been deposited during the electro-precipitation reaction and thus further optimization or post-treatments are required to obtain an active manganese oxide layer for thin film deposits. The key property of this new deposition technique is the self-limiting behavior, proven by rotating ring-disk electrode experiments. This is crucial to electrodeposit thin films conformally on high aspect ratio structures for 3D all-solid-state lithium-ion batteries or supercapacitors. [ABSTRACT FROM AUTHOR]

The oxygen reduction reaction and oxygen evolution reaction (ORR-OER) in DMSO were investigated by cyclic voltammetry and potentiostatic methods. A quartz crystal microbalance (QCM) was used to detect which products are formed during reduction and to evaluate the reversibility of the reactions. The studied parameters include the scan rate and the applied cathodic potential. We confirm by the QCM that LiO2 is soluble: this conclusion comes from the time delay we observed between the deposition of the expected mass (based on Faraday's law) and the measured mass. Ambiguity in reported literature values for the slope of the deposited mass per electron UGRAPHIC DISPLAY="INLINE" ID="UGT1" SRC="UGT1"/ is due to the negligence in considering this time delay. The average UGRAPHIC DISPLAY="INLINE" ID="UGT2" SRC="UGT2"/ value versus cathodic charge indicates that soluble LiO2 is the first product of the ORR which reacts further to form Li2O2, either via a disproportionation reaction or via further electrochemical reduction of LiO2. For strong negative potentials and thus large depths of discharge, Li2O is the main discharge product. The reaction pathways hence strongly depend on the experimental conditions applied; especially the reduction potential. The redox mediator tetrathiafulvalene (TTF) was investigated and its influence on reversibility was confirmed by cycling at moderate depths of discharge, where Li2O2 is the main discharge product. [ABSTRACT FROM AUTHOR]

The electrodeposition of germanium at elevated temperatures up to 180 °C and pressures was studied from the ionic liquids 1-butyl-1-methylpyrrolidinium dicyanamide and 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide containing [GeCl4(BuIm)2] (where BuIm = 1-butylimidazole) or GeCl4. Cyclic voltammetry (CV), electrochemical quartz crystal microbalance (EQCM), rotating ring-disk electrode (RRDE), scanning electron microscope (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), electron backscatter diffraction (EBSD) and Auger electron spectroscopy (AES) were used to investigate the electrochemical behavior and the properties of the electrodeposited germanium. Electrodeposition at elevated temperatures leads to higher deposition rates due to: (1) increase in the diffusion rate of the electroactive germanium compounds; (2) faster electrochemical kinetics in the electrolyte; and (3) higher electrical conductivity of the electrodeposited germanium film. Moreover, the morphology of the germanium film is also of a better quality at higher electrodeposition temperatures due to an increase in adatom mobility. [ABSTRACT FROM AUTHOR]

The general idea of holographic optical data storage (HODS) is briefly introduced. Based on the recent advances of HODS, the key techniques and the challenges of HODS are discussed. Some new techniques are proposed to improve the system. A miniaturized volume holographic data storage and correlation system is presented. It can achieve a density of 10 Gb/cm³ and a fast correlation recognition rate of more than 2000 images per second. It shows the attracting potential advantages over other conventional storage methods in the information storage as well as information processing. [ABSTRACT FROM AUTHOR]

The use of similarity measure techniques on the optical correlation output plane is analysed as a method to improve the discrimination ability of pattern recognition procedures. The study is divided into two parts: one recounts a computer simulated example corresponding to pattern recognition by the use of input images that may be blurred, rotated or corrupted by additive Gaussian noise, and the second part describes a real optical processor for real-time human face recognition, in which the simple similarity measure based postprocessing method plays an important role for improving the discrimination ability while saving much processing time. [ABSTRACT FROM AUTHOR]

It has been widely accepted that spatial beam smoothing is essential in coupling laser energy to inertial confinement fusion targets. In this paper, kinoform phase plate arrays have been proposed to produce spatially homogenized far fields for a broad range of phase and irradiance non-uniformities in the incident beam. A global-local united search algorithm has been presented to design a phase plate element to concentrate more than 95% energy of laser beams on a flat-top super-Gaussian (SG) envelope. A spatial-fining technique has been proposed to control the intermediate-spatial-frequency overlapping intensity modulation generated by various phase plate elements. For a flat incident aperture size of 40 cm, a laser wavelength of 351 nm, and a lens focal length of 1000 mm, 10 × 10 phase plate arrays have been designed to produce sixteenth-order SG profiles with the intensity modulation interval less than 5 μ. More than 96% of the incident energy is homogeneously constrained in the desired region. [ABSTRACT FROM AUTHOR]

Zinc-air batteries (ZABs) and Proton exchange membrane fuel cells (PEMFCs) have attracted wide attention because of their high energy density. However, the oxygen reduction reaction (ORR) occurred at the cathode is 6 orders of magnitude lower than the oxidation reaction occurred at the anode. In recent years, atomically dispersed metal-nitrogen-carbon (M-N-C) catalyst has been widely considered as one of the most promising catalysts to replace platinum-based catalysts. However, the performance of M-N-C catalyst is much lower than that of the most advanced Pt catalysts. The key to improving the catalytic activity of M-N-C ORR catalysts is to increase the intrinsic activity of the catalyst active sites. In this paper, the active sites of atomically dispersed M-N-C ORR catalysts are introduced, and the strategies of enhancing the intrinsic activity of the active sites including heteroatom doping, construction of dual atoms sites and creation rich defects in carbon materials are systematically summarized. Finally, the opportunities and challenges of further development of atomically dispersed M-N-C catalysts are proposed. • A comprehensive overview of atomically dispersed M-N-C catalysts for ORR. • Focus on the enhancement of the intrinsic activity of the active site. • Future directions of developing advanced M-N-C catalysts for ORR are outlined. [ABSTRACT FROM AUTHOR]