High rate capabilities and remarkably cycle-stable flexible pseudocapacitors based on nano-coralloid arrays with sulfide vacancies enhanced Ni-Co-S nanoparticle covering.

Both poor electron conductivity and low ion diffusion of electrode materials are two main issues limiting the rate performance of pseudocapacitors. The present work reports the design and fabrication of hierarchically nano-architectured electrodes consisting of sulfide vacancies enhanced Ni-Co-S nanoparticle covering bent nickel nano-forest (BNNF). We propose new insight into vastly increased ion-accessible active sites and fast charge storage/delivery enhanced the reaction kinetics. The Ni-Co-S@BNNF electrode exhibits extremely high rate performance with 90.1% capacity retention from 1 to 20 A g-1, and even still remains 83.6% capacity at 40 A g-1, much superior to reported NiCo2S4-based electrodes. The high rate performance is attributed to the unique nano-architecture providing increased ion availability of electrochemically active sites and high conductivity for fast electron transport. Especially the electrode achieves remarkable long-term cycle stability with more than 100% initial capacity value after 5000 cycles at 5 A g-1and exhibits excellent cycle reversibility even at 20 A g-1. Goog cycle stability should be attributed to the sulfide vacancies in Ni-Co-S nano-branches and the electrode architecture sustaining structural strain during fast redox reactions. An asymmetric pseudocapacitor applying such electrode achieves a high energy density of 99.9 W h kg-1and exhibits superior cycling stability at a high current density of 20 A g-1. This study underscores the potential importance of developing nanoarrays covered with highly redox-active materials with increasing ions/charge kinetics for energy storage.

Relative Entropy Method Applied for the Fatigue Life Distribution of Carbon Fiber/Epoxy Composites.

This paper verifies the feasibility of the relative entropy method in selecting the most suitable statistical distribution for the experimental data, which do not follow an exponential distribution. The efficiency of the relative entropy method is tested through the fractional order moment and the logarithmic moment in terms of the experimental data of carbon fiber/epoxy composites with different stress amplitudes. For better usage of the relative entropy method, the efficient range of its application is also studied. The application results show that the relative entropy method is not very fit for choosing the proper distribution for non-exponential random data when the heavy tail trait of the experimental data is emphasized. It is not consistent with the Kolmogorov-Smirnov test but is consistent with the residual sum of squares in the least squares method whenever it is calculated by the fractional moment or the logarithmic moment. Under different stress amplitudes, the relative entropy method has different performances.

Phase Separation of Silicon-Containing Polymer/Polystyrene Blends in Spin-Coated Films.

In this Article, two readily available polymers that contain silicon and have different surface tensions, polydimethylsiloxane (PDMS) and polyphenylsilsequioxane (PPSQ), were used to produce polymer blends with polystyrene (PS). Spin-coated thin films of the polymer blends were treated by O2 reactive-ion etching (RIE). The PS constituent was selectively removed by O2 RIE, whereas the silicon-containing phase remained because of the high etching resistance of silicon. This selective removal of PS substantially enhanced the contrast of the phase separation morphologies for better scanning electron microscope (SEM) and atomic force microscope (AFM) measurements. We investigated the effects of the silicon-containing constituents, polymer blend composition, concentration of the polymer blend solution, surface tension of the substrate, and the spin-coating speed on the ultimate morphologies of phase separation. The average domain size, ranging from 100 nm to 10 µm, was tuned through an interplay of these factors. In addition, the polymer blend film was formed on a pure organic layer, through which the aspect ratio of the phase separation morphologies was further amplified by a selective etching process. The formed nanostructures are compatible with existing nanofabrication techniques for pattern transfer onto substrates.

An oxygen-insensitive degradable resist for fabricating metallic patterns on highly curved surfaces by UV-nanoimprint lithography.

In this paper, an oxygen-insensitive degradable resist for UV-nanoimprint is designed, com-prising a polycyclic degradable acrylate monomer, 2,10-diacryloyloxymethyl-1,4,9,12-tetraoxa-spiro [4.2.4.2] tetradecane (DAMTT), and a multifunctional thiol monomer pentaerythritol tetra(3-mercaptopropionate) (PETMP). The resist can be quickly UV-cured in the air atmosphere and achieve a high monomer conversion of over 98%, which greatly reduce the adhesion force between the resist and the soft mold. High conversion, in company with an adequate Young's modulus (about 1 GPa) and an extremely low shrinkage (1.34%), promises high nanoimprint resolution of sub-50 nm. The cross-linked resist is able to break into linear molecules in a hot acid solvent. As a result, metallic patterns are fabricated on highly curved surfaces via the lift off process without the assistance of a thermoplastic polymer layer.

An evaluation of Astragali Radix with different growth patterns and years, based on a new multidimensional comparison method.

Introduction: With the depletion of wild Astragali Radix (WA) resources, imitated-wild Astragali Radix (IWA) and cultivated Astragali Radix (CA) have become the main products of Astragali Radix. However, the quality differences of three growth patterns (WA, IWA, CA) and different growth years of Astragali Radix have not been fully characterized, leading to a lack of necessary scientific evidence for their use as substitutes for WA. Methods: We innovatively proposed a multidimensional evaluation method that encompassed traits, microstructure, cell wall components, saccharides, and pharmacodynamic compounds, to comprehensively explain the quality variances among different growth patterns and years of Astragali Radix. Results and discussion: Our study showed that the quality of IWA and WA was comparatively similar, including evaluation indicators such as apparent color, sectional structure and odor, thickness of phellem, diameter and number of vessels, morphology of phloem and xylem, and the levels and ratios of cellulose, hemicellulose, lignin, sucrose, starch, water-soluble polysaccharides, total-saponins. However, the content of sucrose, starch and sorbose in CA was significantly higher than WA, and the diameter and number of vessels, total-flavonoids content were lower than WA, indicating significant quality differences between CA and WA. Hence, we suggest that IWA should be used as a substitute for WA instead of CA. As for the planting years of IWA, our results indicated that IWA aged 1-32 years could be divided into three stages according to their quality change: rapid growth period (1-5 years), stable growth period (6-20 years), and elderly growth period (25-32 years). Among these, 6-20 years old IWA exhibited consistent multidimensional comparative results, showcasing elevated levels of key active components such as water-soluble polysaccharides, flavonoids, and saponins. Considering both the quality and cultivation expenses of IWA, we recommend a cultivation duration of 6-8 years for growers. In conclusion, we established a novel multidimensional evaluation method to systematically characterize the quality of Astragali Radix, and provided a new scientific perspective for the artificial cultivation and quality assurance of Astragali Radix.

Nonreciprocal resonant transmission/reflection based on a one-dimensional photonic crystal adjacent to the magneto-optical metal film.

We study the nonreciprocal Tamm plasmon polaritons (TPPs) inside the light cone, which can be directly excited at the interface between the one-dimensional photonic crystal (1DPC) and magneto-optical (MO) metal film. Applying an external magnetic field on the MO metal, the broken time-reversal symmetry gives rise to such nonreciprocal electrons oscillation mediated plasmon mode. Separately exciting the forward and backward TPPs, light can be transmitted and reflected in one-way. An analytic dispersion relation based on admittance-matching approach is obtained. This design offers promising potential in realizing the optical diode.

Double transfer UV-curing nanoimprint lithography.

A challenge in the fabrication of nanostructures into non-planar substrates is to form a thin, uniform resist film on non-planar surfaces. This is critical to the fabrication of nanostructures via a lithographic technique due to the subsequent pattern transfer process. Here we report a new double transfer UV-curing nanoimprint technique that can create a nanopatterned thin film with a uniform residual layer not only on flat substrates but also on highly curved surfaces. Surface relief gratings with pitches down to 200 nm are successfully imprinted on the cylindrical surface of optical fibers, and further transferred into a SiO2 matrix using reactive ion etching (RIE), demonstrating that our technique is applicable for fabricating high-resolution nanostructures on non-planar substrates.

Non-Iridescent Metal Nanomesh with Disordered Nanoapertures Fabricated by Phase Separation Lithography of Polymer Blend as Transparent Conductive Film.

Metallic nanomesh, one of the emerging transparent conductive film (TCF) materials with both high electrical conductivity and optical transmittance, shows great potential to replace indium tin oxide (ITO) in optoelectronic devices. However, lithography-fabricated metallic nanomeshes suffer from an iridescence problem caused by the optical diffraction of periodic nanostructures, which has negative effects on display performance. In this work, we propose a novel approach to fabricate large-scale metallic nanomesh as TCFs on flexible polyethylene terephthalate (PET) sheets by maskless phase separation lithography of polymer blends in a low-cost and facile process. Polystyrene (PS)/polyphenylsilsequioxane (PPSQ) polymer blend was chosen as resist material for phase separation lithography due to their different etching selectivity under O2 reactive ion etching (RIE). The PS constituent was selectively removed by O2 RIE and the remained PPSQ nanopillars with varying sizes in random distribution were used as masks for further pattern transfer and metal deposition process. Gold (Au) nanomeshes with adjustable nanostructures were achieved after the lift-off step. Au nanomesh exhibited good optoelectronic properties (RS = 41 Ω/sq, T = 71.9%) and non-iridescence, without angle dependence owing to the aperiodic structures of disordered apertures. The results indicate that this Au nanomesh has high potential application in high-performance and broad-viewing-angle optoelectronic devices.

Hybrid nanoimprint-soft lithography with sub-15 nm resolution.

We developed a hybrid nanoimprint-soft lithography technique with sub-15 nm resolution. It is capable of patterning both flat and curved substrates. The key component of the technology is the mold, which consists of rigid features on an elastic poly(dimethylsiloxane) (PDMS) support. The mold was fabricated by imprinting a reverse image onto the PDMS substrate using a UV-curable low-viscosity prepolymer film. Patterns with sub-15-nm resolution were faithfully duplicated on a flat substrate without applying external pressure. Gratings at 200 nm pitch were also successfully imprinted onto the cylindrical surface of a single mode optical fiber with a 125 microm diameter.

A Rapid Thermal Nanoimprint Apparatus through Induction Heating of Nickel Mold.

Thermal nanoimprint lithography is playing a vital role in fabricating micro/nanostructures on polymer materials by the advantages of low cost, high throughput, and high resolution. However, a typical thermal nanoimprint process usually takes tens of minutes due to the relatively low heating and cooling rate in the thermal imprint cycle. In this study, we developed an induction heating apparatus for the thermal imprint with a mold made of ferromagnetic material, nickel. By applying an external high-frequency alternating magnetic field, heat was generated by the eddy currents and magnetic hysteresis losses of the ferromagnetic nickel mold at high speed. Once the external alternating magnetic field was cut off, the system would cool down fast owe to the small thermal capacity of the nickel mold; thus, providing a high heating and cooling rate for the thermal nanoimprint process. In this paper, nanostructures were successfully replicated onto polymer sheets with the scale of 4-inch diameter within 5 min.

Precision Imprinted Nanostructural Wood.

Wood is a ubiquitous material, widely used in human society, that features naturally abundant, aligned longitudinal cells (e.g., tracheids in softwood and fibers/vessels in hardwood) with diameters of ≈50-1000 µm. Here, the realization of, fine patterns on a wood surface ranging in size from 40 nm to 50 µm by precision imprinting is described. The precision imprinting is enabled by releasing cellulose fibril aggregates from the bondage of lignin through the delignification process, then imprinting in wet condition and fixing the designed configuration in the dry state. Various precision structures on a wood surface using imprinting technology, including dot arrays, lines, triangular features, and other complex patterns, are successfully demonstrated. Even multiscale structures with nanosized lines on the surface of micrometer hemiballs can be acquired. As a proof of concept, the use of surface-imprinted wood as a microlens array (MLA), which exhibits superior imaging ability and thermal stability even at a high temperature up to 150 °C compared with traditional polystyrene MLA, is demonstrated. This precision imprinted wood may open new possibilities toward environmentally friendly devices and applications in optics, biology, electronics, etc.

Wafer Scale Fabrication of Dense and High Aspect Ratio Sub-50 nm Nanopillars from Phase Separation of Cross-Linkable Polysiloxane/Polystyrene Blend.

We demonstrated a simple and effective approach to fabricate dense and high aspect ratio sub-50 nm pillars based on phase separation of a polymer blend composed of a cross-linkable polysiloxane and polystyrene (PS). In order to obtain the phase-separated domains with nanoscale size, a liquid prepolymer of cross-linkable polysiloxane was employed as one moiety for increasing the miscibility of the polymer blend. After phase separation via spin-coating, the dispersed domains of liquid polysiloxane with sub-50 nm size could be solidified by UV exposure. The solidified polysiloxane domains took the role of etching mask for formation of high aspect ratio nanopillars by O2 reactive ion etching (RIE). The aspect ratio of the nanopillars could be further amplified by introduction of a polymer transfer layer underneath the polymer blend film. The effects of spin speeds, the weight ratio of the polysiloxane/PS blend, and the concentration of polysiloxane/PS blend in toluene on the characters of the nanopillars were investigated. The gold-coated nanopillar arrays exhibited a high Raman scattering enhancement factor in the range of 108-109 with high uniformity across over the wafer scale sample. A superhydrophobic surface could be realized by coating a self-assembled monolayers (SAM) of fluoroalkyltrichlorosilane on the nanopillar arrays. Sub-50 nm silicon nanowires (SiNWs) with high aspect ratio of about 1000 were achieved by using the nanopillars as etching mask through a metal-assisted chemical etching process. They showed an ultralow reflectance of approximately 0.1% for wavelengths ranging from 200 to 800 nm.

Total flavonoid extract from Coreopsis tinctoria Nutt. protects rats against myocardial ischemia/reperfusion injury.

OBJECTIVES: This study aimed to evaluate the protective effects of total flavonoid extract from Coreopsis tinctoria Nutt. (CTF) against myocardial ischemia/reperfusion injury (MIRI) using an isolated Langendorff rat heart model. MATERIALS AND METHODS: Left ventricular developed pressure (LVDP) and the maximum rate of rise and fall of LV pressure (±dp/dtmax) were recorded. Cardiac injury was assessed by analyzing lactate dehydrogenase (LDH) and creatine kinase (CK) released in the coronary effluent. Superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) levels were determined. Myocardial inflammation was assessed by monitoring tumor necrosis factor-alpha (TNF-α), C-reactive protein (CRP), interleukin-8 (IL-8), and interleukin-6 (IL-6) levels. Myocardial infarct size was estimated. Cell morphology was assessed by 2,3,5-triphenyltetrazolium chloride and hematoxylin and eosin (HE) staining. Cardiomyocyte apoptosis was determined by terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining. RESULTS: Pretreatment with CTF significantly increased the heart rate and increased LVDP, as well as SOD and GSH-Px levels. In addition, CTF pretreatment decreased the TUNEL-positive cell ratio, infarct size, and levels of CK, LDH, MDA, TNF-α, CRP, IL-6, and IL-8. CONCLUSION: These results suggest that CTF exerts cardio-protective effects against MIRI via anti-oxidant, anti-inflammatory, and anti-apoptotic activities.

Cardioprotective Effects of Total Flavonoids Extracted from Xinjiang Sprig Rosa rugosa against Acute Ischemia/Reperfusion-Induced Myocardial Injury in Isolated Rat Heart.

This study evaluated the antioxidative and cardioprotective effects of total flavonoids extracted from Xinjiang sprig Rosa rugosa on ischemia/reperfusion (I/R) injury using an isolated Langendorff rat heart model. The possible mechanism of Xinjiang sprig rose total flavonoid (XSRTF) against I/R injury was also studied. XSRTF (5, 10, and 20 µg/mL) dissolved in Krebs-Henseleit buffer was administered to isolated rat heart. The XSRTF showed remarkable scavenging effects against 1,1-diphenyl-2-picrylhydrazyl, hydroxyl, and superoxide anion radicals in vitro. XSRTF pretreatment improved the heart rate, increased LVDP, and decreased CK and LDH levels in coronary flow. This pretreatment also increased SOD activity and GSH/GSSG ratio but decreased MDA, TNF-α, and CRP levels and IL-8 and IL-6 activities. The infarct size and cell apoptosis in the hearts from the XSRTF-treated group were lower than those in the hearts from the I/R group. Therefore, the cardioprotective effects of XSRTF may be attributed to its antioxidant, antiapoptotic, and anti-inflammatory activities.

A New Strategy of Lithography Based on Phase Separation of Polymer Blends.

Herein, we propose a new strategy of maskless lithographic approach to fabricate micro/nano-porous structures by phase separation of polystyrene (PS)/Polyethylene glycol (PEG) immiscible polymer blend. Its simple process only involves a spin coating of polymer blend followed by a development with deionized water rinse to remove PEG moiety, which provides an extremely facile, low-cost, easily accessible nanofabrication method to obtain the porous structures with wafer-scale. By controlling the weight ratio of PS/PEG polymer blend, its concentration and the spin-coating speed, the structural parameters of the porous nanostructure could be effectively tuned. These micro/nano porous structures could be converted into versatile functional nanostructures in combination with follow-up conventional chemical and physical nanofabrication techniques. As demonstrations of perceived potential applications using our developed phase separation lithography, we fabricate wafer-scale pure dielectric (silicon)-based two-dimensional nanostructures with high broadband absorption on silicon wafers due to their great light trapping ability, which could be expected for promising applications in the fields of photovoltaic devices and thermal emitters with very good performances, and Ag nanodot arrays which possess a surface enhanced Raman scattering (SERS) enhancement factor up to 1.64 × 10(8) with high uniformity across over an entire wafer.

A fast thermal-curing nanoimprint resist based on cationic polymerizable epoxysiloxane.

We synthesized a series of epoxysiloxane oligomers with controllable viscosity and polarity and developed upon them a thermal-curable nanoimprint resist that was cross-linked in air at 110°C within 30 s if preexposed to UV light. The oligomers were designed and synthesized via hydrosilylation of 4-vinyl-cyclohexane-1,2-epoxide with poly(methylhydrosiloxane) with tunable viscosity, polarity, and cross-linking density. The resist exhibits excellent chemical and physical properties such as insensitivity toward oxygen, strong mechanical strength, and high etching resistance. Using this resist, nanoscale patterns of different geometries with feature sizes as small as 30 nm were fabricated via a nanoimprint process based on UV-assisted thermal curing. The curing time for the resist was on the order of 10 s at a moderate temperature with the help of UV light preexposure. This fast thermal curing speed was attributed to the large number of active cations generated upon UV exposure that facilitated the thermal polymerization process.