Abstract
Electrospinning has received a lot of attention in recent years because it can create nonwoven nanofiber webs with high surface area and porosity. However, the typical needle and ...syringe‐based electrospinning systems feature poor productivity that has limited their usefulness in the industrial field. Here, current developments in the creation of nanofibers employing nonconventional electrospinning methods, such as needleless electrospinning and syringeless electrospinning, are examined. These alternate electrospinning techniques, which are dependent on numerous polymer droplets of varied shapes, have the potential to match the productivity required for industry‐scale manufacturing of nanofibers. Additionally, they make it possible to produce nanofibers that are difficult to spin using traditional techniques, like electrospinning of colloidal suspensions.
Fourth-generation storage rings (4GSRs) that exploit the multi-bend achromat lattice concept may be able to surpass the brightness and coherence that are attained using the present third-generation ...storage rings. This paper presents the characteristics of photon beams and an analysis of their coherence properties in Korea-4GSR to represent 4GSRs.
Colloidal electrospinning is identified as a powerful tool for the fabrication of nonwoven nanofiber webs with increased functionality by the introduction of functional fillers into the webs. ...However, the use of this method is still limited due to minimal material diversity, low concentration of fillers, difficulty in mass production, and process difficulties. In this paper, syringeless electrospinning is suggested as an excellent method for colloidal electrospinning. Since the polymeric solution is supplied from the container through rotating drums, this method is relatively free from the precipitation of fillers present in the polymeric solution. Syringeless electrospinning provides a higher production rate than needle‐based electrospinning with simple process control. The syringeless technique makes it possible to expand the scope of the method to various polymers and inorganic fillers with sufficiently high filler concentrations. Herein, nonwoven nanofiber webs with a diverse combination of polymers (polyacrylonitrile (PAN), thermoplastic polyurethane (TPU), and polyvinylpyrrolidone (PVP)) and fillers (silica, titania, zirconia, activated carbons, and metal‐organic framework (MOF) crystals) are presented. Nonwoven nanofiber webs comprising PAN and UiO‐66‐NH2 MOF crystal are prepared for detoxification of a nerve agent simulant, diisopropyl fluorophosphate (DFP), as a representative example of applications.
Colloid syringeless electrospinning has advantages for improving the production rate compared to conventional needle‐based electrospinning. Various kinds of polymer nanofiber nonwoven webs are produced with large amount of fillers via colloid syringeless electrospinning. Depending on the polymer and filler used, the function of nonwoven web can be changed and applied to various fields.
A multi‐objective genetic algorithm (MOGA) is a powerful global optimization tool, but its results are considerably affected by the crossover parameter ηc. Finding an appropriate ηc demands too much ...computing time because MOGA needs be run several times in order to find a good ηc. In this paper, a self‐adaptive crossover parameter is introduced in a strategy to adopt a new ηc for every generation while running MOGA. This new scheme has also been adopted for a multi‐generation Gaussian process optimization (MGGPO) when producing trial solutions. Compared with the existing MGGPO and MOGA, the MGGPO and MOGA with the new strategy show better performance in nonlinear optimization for the design of low‐emittance storage rings.
A self‐adaptive crossover parameter is introduced in a strategy to adopt a new ηc for every generation while running a multi‐objective genetic algorithm.
Anisotropic microstructures are utilized in various fields owing to their unique properties, such as reversible shape transitions or on‐demand and sequential release of drug combinations. In this ...study, anisotropic multicompartmental microfibers composed of different polymers are prepared via charge reversal electrohydrodynamic (EHD) co‐jetting. The combination of various polymers, such as thermoplastic polyurethane, poly(D,L‐lactide‐co‐glycolide), poly(vinyl cinnamate), and poly(methyl methacrylate), results in microfibers with distinct compositional boundaries. Charge reversal during EHD co‐jetting enables facile fabrication of multicompartmental microfibers with the desired composition and tunable inner architecture, broadening their spectrum of potential applications, such as functional microfibers and cell scaffolds with multiple physical and chemical properties.
Multicompartmental microfibers composed of diverse polymer combinations are fabricated using charge reversal electrohydrodynamic co‐jetting method. Adjusting parameters such as applied voltage, flow rate, and polymer solution concentration, allows each polymer to stably constitute each compartment of a single microfiber. The anisotropic microfibers can offer distinct chemical and mechanical properties in a single structure.
Storage rings that use the hybrid multi-bend achromat (MBA) lattice concept 1 have been realized. The main characteristics of hybrid MBA as a typical lattice for a 4th generation storage ring are to ...adopt two large dispersion bumps in cell, and to make a -I-transformation between two dispersion bumps to cancel nonlinear effects. To increase the effectiveness of nonlinear control, analytical investigation of nonlinear phenomenon is essential. In this paper, we describe analytical investigation with a nonlinear driving term and simple model. We obtained similar results to the existing time-consuming MOGA optimization, but use a simplex optimizer with fewer nonlinear control knobs.
The need for high-precision microprinting processes that are controllable, scalable, and compatible with different materials persists throughout a range of biomedical fields. Electrospinning ...techniques offer scalability and compatibility with a wide arsenal of polymers, but typically lack precise three-dimensional (3D) control. We found that charge reversal during 3D jet writing can enable the high-throughput production of precisely engineered 3D structures. The trajectory of the jet is governed by a balance of destabilizing charge-charge repulsion and restorative viscoelastic forces. The reversal of the voltage polarity lowers the net surface potential carried by the jet and thus dampens the occurrence of bending instabilities typically observed during conventional electrospinning. In the absence of bending instabilities, precise deposition of polymer fibers becomes attainable. The same principles can be applied to 3D jet writing using an array of needles resulting in complex composite materials that undergo reversible shape transitions due to their unprecedented structural control.
This paper describes solutions to calibrate the photon beam from the gradient bending magnet and to minimize the cross-talk between blades in the photon-beam position monitors in beamlines at Pohang ...Light Source II. The cross-talk was reduced by 99% applying the sensitivity normalization for each electrodes. The precise calibration was also achieved by considering additional kicks in the gradient bending magnet. The focusing force by quadrupole component in the bending magnet gives rise to an effect that simultaneously changes the vertical displacement of the source point and the emission angle. Experimental results agreed well with the transfer matrix calculations.
A description of the upgraded bunch‐by‐bunch feedback system for time‐resolved experiments at Pohang Light Source II (PLS‐II) is provided. The bunch‐by‐bunch feedback system has been upgraded to ...increase the single‐bunch current in the hybrid fill pattern of the PLS‐II facility. The project is part of the SPring‐8 and PLS‐II collaboration. The main features of the upgrade are to employ a single 500 MHz analog‐to‐digital converter (ADC) instead of the previous four 125 MHz interleaved ADCs for 500 MHz rate, to replace a single‐loop two‐dimensional feedback with two independent one‐dimensional feedback loops, to implement the tune measurement function with a single bunch, and mainly to implement single‐bunch and stretcher control. The realization of a 400 mA hybrid fill pattern including a 10 mA single bunch demonstrates the precision of the upgraded bunch‐by‐bunch feedback system.
A description of the upgraded bunch‐by‐bunch feedback system for time‐resolved experiments at Pohang Light Source II (PLS‐II) is provided. The project is part of the SPring‐8 and PLS‐II collaboration.
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