Dipolar Microenvironment Engineering Enabled by Electron Beam Irradiation for Boosting Catalytic Performance.

Creating a diverse dipolar microenvironment around the active site is of great significance for the targeted induction of intermediate behaviors to achieve complicated chemical transformations. Herein, an efficient and general strategy is reported to construct hypercross-linked polymers (HCPs) equipped with tunable dipolar microenvironments by knitting arene monomers together with dipolar functional groups into porous network skeletons. Benefiting from the electron beam irradiation modification technique, the catalytic sites are anchored in an efficient way in the vicinity of the microenvironment, which effectively facilitates the processing of the reactants delivered to the catalytic sites. By varying the composition of the microenvironment scaffold structure, the contact and interaction behavior with the reaction participants can be tuned, thereby affecting the catalytic activity and selectivity. As a result, the framework catalysts produced in this way exhibit excellent catalytic performance in the synthesis of glycinate esters and indole derivatives. This manipulation is reminiscent of enzymatic catalysis, which adjusts the internal polarity environment and controls the output of products by altering the scaffold structure.

Skin-Inspired, Highly Sensitive, Broad-Range-Response and Ultra-Strong Gradient Ionogels Prepared by Electron Beam Irradiation.

Skin, characterized by its distinctive gradient structure and interwoven fibers, possesses remarkable mechanical properties and highly sensitive attributes, enabling it to detect an extensive range of stimuli. Inspired by these inherent qualities, a pioneering approach involving the crosslinking of macromolecules through in situ electron beam irradiation (EBI) is proposed to fabricate gradient ionogels. Such a design offers remarkable mechanical properties, including excellent tensile properties (>1000%), exceptional toughness (100 MJ m-3), fatigue resistance, a broad temperature range (-65-200°C), and a distinctive gradient modulus change. Moreover, the ionogel sensor exhibits an ultra-fast response time (60 ms) comparable to skin, an incredibly low detection limit (1 kPa), and an exceptionally wide detection range (1 kPa-1 MPa). The exceptional gradient ionogel material holds tremendous promise for applications in the field of smart sensors, presenting a distinct strategy for fabricating flexible gradient materials.

Power supply for fast-scanning magnet in proton therapy: Design and test.

Proton therapy is one of the most effective radiation methods to combat cancer and offers a substantial advantage over conventional photon therapy. Magnetic scanning systems consisting of a magnet and power supply form an integral part of proton therapy and allow the beam position (x, y) to be controlled during spot scanning. Ensuring that the dose is rapidly and precisely distributed within the contour of the tumor requires a high-precision, fast-ramp-speed, and high-stability power supply with accurate control. The present work uses a three-phase bridge rectifier and multiple series-parallel H-bridge converters to propose a prototype power supply for the scanning magnet of a magnetic scanning system. The power supply is controlled using a proportional integral controller using digital signal processing. A prototype of the scanning power supply is developed and tested, and the results demonstrate an output current of ±500 A, a ramp speed of ±40 kA/s, and a short- and long-term stability of less than 20 ppm.

Design and optimization of scanning magnets for HUST-PTF.

We report scanning magnets manufactured at the Huazhong University of Science and Technology Proton Therapy Facility for use in pencil-beam nozzles in a fixed beamline. Such nozzles allow us to control the trajectory of proton beams to form the requisite radiation field for tumor therapy. Two AC-excited scanning magnets operate at a maximum frequency of 100 and 50 Hz, respectively, generating significant eddy currents that raise the temperature. We use transient electromagnetic analysis and thermal analysis to study the eddy current effect and control the temperature. In this paper, the maximum temperature rise of the scanning magnets is taken as the criterion to find the appropriate depth, shape, and distribution of slits. After the slits are optimized, the temperature rise of the scanning magnet is significantly reduced. Finally, the results of DC performance tests satisfy the requirements of the magnetic field.