This study investigates the hourglass–spindle-shaped trajectory of electron motion based on a model of electron and circularly polarized chirped laser pulse coaxial collision. The velocity, acceleration, and radiation distribution of the electron in this state of motion are systematically analyzed. The formation process of the hourglass–spindle-shaped trajectory is examined in detail. Four distinct stages of the electron–laser pulse collision process are proposed, with an in-depth analysis of the interaction dynamics and underlying mechanisms in each stage. The critical conditions for the formation of the hourglass–spindle-shaped trajectory are identified, along with the conditions for the emergence of two other possible trajectories resulting from the collision: the spiral-shaped and spindle-shaped trajectories. Additionally, a general model for analyzing electron–laser pulse collisions is proposed.

• Book : 15(6)
• Pub. Date : 2025
• Page : pp.3013-3013
• Keyword :

The environment in Tokamak fusion reactor is hostile to remote handling (RH) equipment that maintains invessel components. Many maintenance tasks include transferring components, pipe cutting, and welding in the vacuum vessel (VV). To fulfill these maintenance works, a 7- degree-of-freedom (DOF) heavy load manipulator and a 3-DOF end-effector are designed and connected together to form a 10-DOF redundant robot. The inverse kinematics for such a high redundancy robot, considering obstacle avoidance in the complex space of VV, is a challenge. To solve this problem, the Jacobian method is adopted, and a method specially designed for obstacle avoidance of redundant robots working in the VV is integrated to simplify algorithm calculation and improve inverse solution efficiency. The algorithm is applied to solve the inverse kinematics of the redundant robot for the maintenance of the divertor plasma facing components (PFC) in VV. The results show that the inverse kinematics of the redundant robot can be solved quickly with high positioning accuracy. The method can also be used for other fusion reactor maintenance robots with some adjustments. The maintenance efficiency of redundant robot can be improved with the method which can be valuable for the whole remote handling process

• Book : 57(4)
• Pub. Date : 2025
• Page : pp.3-30
• Keyword :

AbstractFruits and vegetables suffer severe moisture loss during cold storage. To explore the mechanism of water transfer, this study investigated the properties of konjac glucomannan (KGM)/curdlan (KC) composite films after cold storage treatment, the preservation of KC‐coated cucumbers, and the water transfer. The results showed that the weight, thickness, free water content, and enthalpy (ΔH) of endothermic peak of the film increased after cold storage, mainly because of the water adsorption and diffusion. K6C4 (the KGM/curdlan mass ratio in 6:4) maintained uniform and dense and showed the lowest dissolution loss of 21.92%. Moreover, the water content of K6C4 film changed by 1.1% on day 15, and K6C4 exhibited excellent gas barrier and mechanical properties. These were attributed to the optimal matrix formed by the assembly of KGM and curdlan in K6C4, contributing to the stability of structure and performance. K6C4 coating significantly maintained the quality of cucumbers. At the end of storage, the firmness and weight loss of the coating group were 19.3% and 24.4% higher than the control group, respectively. The color, total solid content, acid, and VC were maintained for coating group. The low‐field nuclear magnetic resonance revealed that K6C4 coating inhibited the water transfer from the center to the epidermis of cucumbers by blocking the water produced by respiration and the free water in the tissues. The storage stability and water transfer analysis will contribute to the understanding of the mechanism of coating inhibiting moisture loss of fruits and vegetables.

• Book : 90(3)
• Pub. Date : 2025
• Page :
• Keyword :

Time-of-flight (TOF) is a method to boost reconstructed image signal-to-noise ratio in positron emission tomography (PET); the SNR gain increases as detector coincidence time resolution (CTR) improves. It is also desirable to control detector costs, especially when developing long axial field of view PET systems. With these two goals in mind, it has been proposed to exploit the prompt luminescence, predominantly Cherenkov light, in the scintillation crystal BGO, to estimate the annihilation photon arrival time for PET detectors. However, properly identifying the relatively low number of Cherenkov photons generated per interaction event in BGO is not easy, requires low noise photodetectors, fast readout electronics, and accurate signal processing techniques.Since Cherenkov photons are produced in the ultra-violet (UV) realm, photosensor technology with enhanced performance in the UV region is essential for best performance. In this work we have evaluated and compared the performance of three different UV-enhanced silicon photomultiplier (SiPMs) coupled to 3 × 3 mm2 BGO scintillators ranging from 3 mm to 15 mm length, and two different readout circuits. State-of-the-art data postprocessing methods have been employed for CTR estimation, consistently yielding CTR values < 300 ps fullwidth- at-half-maximum (FWHM) for all crystal lengths studied. To our knowledge, this is the first work comparing these UV-SiPM models under the same conditions

• Book : 57(4)
• Pub. Date : 2025
• Page : pp.265-274
• Keyword :

This study explores the corrosion protection characteristics of nickel (Ni) cladding on Type 316H stainless steel in molten chloride salt environments, relevant to molten salt reactors (MSRs) which are gaining interest as advanced and sustainable nuclear energy sources. Type 316H stainless steel, while noted for its high-temperature strength and corrosion resistance, faces significant challenges when exposed to corrosive molten salts. To address this, Ni cladding was applied using gas tungsten arc (GTA) welding and directed energy deposition (DED) laser cladding. Characterization of the cladding layers was performed using field-emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectroscopy (EDS), identifying precipitates such as Ti(C,N) and Cr₂O₃. Mechanical integrity was verified through bending tests in accordance with ASTM E190-21, which revealed no cracks in the cladding layers. Corrosion resistance was assessed through immersion tests in a 57 mol % NaCl - 43 mol% MgCl₂ mixture at 650 ◦C for 502 h. Results demonstrated superior corrosion resistance of Niclad specimens compared to uncoated Type 316H stainless steel and Incoloy 800H, with the Ni cladding exhibiting a weight increase due to Fe deposition from the Fe-base alloys. The study concludes that Ni cladding, irrespective of the application method, enhances the durability and longevity of Type 316H stainless steel in the harsh environments typical of MSRs, suggesting a promising approach to improving the performance of structural materials in these systems

• Book : 57(4)
• Pub. Date : 2025
• Page : pp.3-30
• Keyword :

Abstract This paper calculates the stochastic gravitational wave background from dark binaries with finite-range attractive dark forces, complementing previous works which consider long-range dark forces. The finiteness of the dark force range can dramatically modify both the initial distributions and evolution histories of the binaries. The generated gravitational wave spectrum is enhanced in the intermediate frequency regime and exhibits interesting “knee” and “ankle” features, the most common of which is related to the turn on of the dark force mediator radiation. Other such spectral features are related to changes in the binary merger lifetime and the probability distribution for the initial binary separation. The stochastic gravitational wave background from sub-solar-mass dark binaries is detectable by both space- and ground-based gravitational wave observatories.

• Book : 2025(03)
• Pub. Date : 2025
• Page : pp.010-010
• Keyword :

Melioidosis is an endemic tropical disease caused by Burkholderia pseudomallei. It typically causes pulmonary disease and bacteraemia but can disseminate to cause multi-organ disease. 18-F FDG PET/CT has an evolving role in diagnosing other infectious diseases, especially where the pathogen or extent of infection is challenging to elucidate clinically and with conventional imaging (CT, US and MRI). We present a case series of patients diagnosed with melioidosis who also underwent 18-F FDG PET/CT from December 18th 2018 to September 30th 2022. Indications for imaging were categorised and analysed as to whether 18-F FDG PET/CT changed management over conventional imaging. Twenty-one 18-F FDG PET/CT scans were performed for sixteen patients. Two scans (9.5%) performed for pyrexia of unknown origin changed management in both cases. Twelve scans (57.1%) performed to ascertain the extent of dissemination of melioidosis changed management in only three (25%) cases. Five scans (23.8%) performed to monitor the response to treatment of known foci changed management in all five cases. Five scans (23.8%) performed for suspected or known malignancy changed management in three (60%) cases. 18-F FDG PET/CT is an emerging tool which improves diagnosis and changes the management of melioidosis when applied judiciously and for well-selected indications.

• Book : 10(3)
• Pub. Date : 2025
• Page : pp.69-69
• Keyword :

Abstract Merger rate predictions of massive black hole (MBH) seeds from large-scale cosmological simulations differ widely, with recent studies highlighting the challenge of low-mass MBH seeds failing to reach the galactic center, a phenomenon known as the seed sinking problem. In this work, we tackle this issue by integrating cosmological simulations and galaxy merger simulations from the MAGICS-I and MAGICS-II resimulation suites with high-resolution N-body simulations. Building on the findings of MAGICS-II, which showed that only MBH seeds embedded in stellar systems are able to sink to the center, we extend the investigation by incorporating nuclear star clusters (NSCs) into our models. Utilizing N-body resimulations with up to 107 particles, we demonstrate that interactions between NSCs and their surrounding galactic environment, particularly tidal forces triggered by cluster interactions, significantly accelerate the sinking of MBHs to the galactic center. This process leads to the formation of a hard binary in ≲500 Myr after the onset of a galaxy merger. Our results show that in eight out of 12 models, the high stellar density of the surrounding NSCs enhances MBH hardening, facilitating gravitational-wave mergers by redshift z = 4. We conclude that at z > 4, dense NSCs serve as the dominant channel for MBH seed mergers, producing a merger rate of 0.3–0.6 yr−1 at z = 4, which is approximately 300–600 times higher than in non-NSC environments. In contrast, in environments without NSCs, surrounding dark matter plays a more significant role in loss-cone scattering.

• Book : 981(2)
• Pub. Date : 2025
• Page : pp.203-203
• Keyword :

Abstract The Heavy-Ion Research Facility in Lanzhou (HIRFL) and the High Intensity heavy-ion Accelerator Facility (HIAF) are essential platforms for heavy-ion scientific research in Asia. These experimental facilities aim to enhance advanced experimental conditions for research in heavy-ion physics and related interdisciplinary fields. In the context of large-scale scientific experimental facilities, higher demands have been proposed on the radiation resistance and transmission speed of the transmission links. The clock and data recovery (CDR) circuit is one of the core circuits of the high-speed transmission links. It can extract the clock information from high-speed serial data and recover the clock for sampling optimally at the center of a unit interval (UI), improving the quality of data transmission in physical experiments. This paper presents a 20 Gbps CDR ASIC in a 55 nm CMOS technology, aiming for data transmission in physics experiments. It is based on a quarter-rate architecture. The area of the core CDR is 0.226 mm2, and the power efficiency is 13.53 pJ/bit with a supply voltage of 1.2 V. The irradiation tolerance of the CDR is improved through radiation-hardened by design (RHBD) techniques and triple-mode redundancy (TMR) at critical nodes.

• Book : 20(03)
• Pub. Date : 2025
• Page : pp.C03017-C03017
• Keyword :

Abstract We present the detection and characterization of fluctuations in linearly polarized emission from the atmosphere above the South Pole. These measurements make use of data from the SPT-3G receiver on the South Pole Telescope in three frequency bands centered at 95, 150, and 220 GHz. We use the cross-correlation between detectors to produce an unbiased estimate of the power in Stokes I, Q, and U parameters on large angular scales. Our results are consistent with the polarized signal being produced by the combination of Rayleigh scattering of thermal radiation from the ground and thermal emission from a population of horizontally aligned ice crystals with an anisotropic distribution described by Kolmogorov turbulence. The measured spatial scaling, frequency scaling, and elevation dependence of the polarized emission are explained by this model. Polarized atmospheric emission has the potential to significantly impact observations on the large angular scales being targeted by searches for inflationary B-mode CMB polarization. We present the distribution of measured angular power spectrum amplitudes in Stokes Q and I for 4 yr of Austral winter observations, which can be used to simulate the impact of atmospheric polarization and intensity fluctuations at the South Pole on a specified experiment and observation strategy. We present a mitigation strategy that involves both downweighting significantly contaminated observations and subtracting a polarized atmospheric signal from the 150 GHz band maps. In observations with the SPT-3G instrument, the polarized atmospheric signal is a well-understood and subdominant contribution to the measured noise after implementing the mitigation strategies described here.

• Book : 982(1)
• Pub. Date : 2025
• Page : pp.15-15
• Keyword :