Terbium-161 (161Tb) is regarded as a highly promising radionuclide for therapeutic applications due to its emission of not only β− particles but also conversion electrons and Auger electrons. This unique decay characteristic makes it particularly effective for eliminating micrometastases. To fully exploit the therapeutic potential of 161Tb while addressing issues such as severe off-target toxicity and low tumor-to-non-tumor uptake ratios caused by the large molecular weight and slow clearance of antibodies in traditional radioimmunotherapy (RIT), this study innovatively employs the pretargeting radioimmunotherapy (PRIT) strategy combined with 161Tb. By decoupling the targeting and radionuclide delivery processes, this approach effectively reduces the radiation background in the blood and normal organs. In this study, cetuximab was selected as the primary antibody targeting the epidermal growth factor receptor (EGFR), and peptide nucleic acid (PNA)—a DNA analog with excellent in vivo stability and high hybridization affinity—was employed for the first time as a 161Tb labelled pretargeting agent. We successfully designed and synthesized a 161Tb-labeled PNA-mediated pretargeting radiopharmaceutical, and subsequently conducted a comprehensive evaluation of its in vivo biodistribution, SPECT/CT imaging, and antitumor effects in the HCC827 xenograft mouse model. The experimental results showed that group A (Cetuximab-PNA-1 + [161Tb]Tb-PNA-2) exhibited significantly reduced radioactive accumulation in the blood and a significantly increased tumor-to-background ratio compared with group B ([161Tb]Tb-DOTA-Cetuximab). After 4 weeks of treatment, compared to the control group, a significant tumor growth inhibition was observed in group A (Cetuximab-PNA-1 + [161Tb]Tb-PNA-2). Construction of PNA mediated pretargeting strategy platform and in vivo mechanism.

Laser polishing technology can significantly improve the laser-induced damage threshold of optics. However, large residual stress induced by surface densification and material modification seriously affects surface accuracy and service life. To avoid these negative effects, this work proposes an in-situ and efficient inhibition strategies of residual stress. A 3D multi-physics coupling model considering temperature evolution, plastic deformation, stress-strain formation and structural relaxation is innovatively established. The formation process of residual stress including stress initiation, stress increases as the structure transitions into non-equilibrium state, and volume shrinkage after solidification is analyzed. The 3D distribution of residual stress induced by laser polishing is first explored. The maximum stress position and stress-induced optical path difference are obtained through crack experiments and birefringence measurement system, thereby verifying the accuracy of the model established. The results show that large residual tensile stress around the polishing boundary, where the fictive temperature (Tf) gradient is maximum, is the reason for crack formation after polishing. Then, the effect of laser process parameters on residual stress distribution is investigated systematically. Using slow speed and high substrate temperature can reduce the cooling rate of the material, then achieve low residual stress. Additionally, the inhibition mechanism of residual stress through laser in-situ annealing is innovatively revealed. Three annealing stress states following laser annealing are proposed based on the Tf distribution inside the optic. The residual stress can be effectively inhibited by reducing Tf inside the heat-affected zones (HAZ) with no depth increment of HAZ, which is defined as full annealing state. After that, the critical factors required to achieve optimal annealing results are identified. By measuring the molecular vibration states through Raman spectrometer, the residual stress and Tf after parameter optimization and laser in-situ annealing are characterized. The increment of Tf is reduced by 43 %, residual stress is reduced by 46 %, and critical crack size for material fracture induced by stress is increased by 245 %, which means that laser damage will be very difficult to induce cracks and destroy the optics. Finally, the measured result of surface profile shows that the inhibition strategies customized in this work also helps mitigate the surface densification induced by laser polishing. This work reveals the mechanism of residual stress formation involved in laser polishing and provides effective and efficient inhibition strategies of residual stress, laying a theoretical foundation for the high-performance manufacturing of optics.

In this work, we systematically studied the roughness development in plasma etching under shadowing effect based on (2 + 1) dimensional Monte Carlo system. Previous works on such subject focus on the cases of ion-driven etching, other types of plasma etching have not been clearly elucidated. In this work, we propose a more general model that employs all the reactive species, which allows us to study the roughness development in all types of plasma etching. First, the individual effects of shadowing growth by etching inhibitor, shadowing etching by radical and random etching by ion on roughness development are investigated. Then, the combined effects of these mechanisms in each type of plasma etching are further studied. This study contributes to the understanding and controll of roughness development for both smooth etching and nano-texturing.

For phase-shaping optical elements with random continuous surface structures, conventional fabrication techniques are inherently limited by tool dimensions, typically achieving minimum feature sizes on the order of millimeters. When addressing beam-shaping requirements for optical apertures several millimeters in scale, this limitation results in an insufficient number of control units within the aperture. Consequently, key beam quality indicators, such as uniformity, are adversely impacted. In this study, a new manufacturing technology for random continuous surface structures has been proposed. This technology employs a two-step process. Firstly, a CO2 laser irradiates the fused silica to selectively alter the fictive temperature distribution within the material's surface and subsurface. Secondly, this fictive-temperature modified region undergoes chemical etching to reveal random continuous surface structures due to the different etching rates with different fictive temperatures. Previous studies have shown that after CO2 laser irradiation, the fictive temperature in the subsurface of fused silica exhibits a spherical cap distribution. Based on this characteristic, uniformly distributed micro-lens arrays have been fabricated. However, the formation of random continuous surface structures has not been reported. Focuses on the formation of random continuous surface structures, this paper established, for the first time, that within a specific parameter range, the laser irradiation parameters exhibit a linear relationship with the final etched contour. Experimental results demonstrate that the minimum lateral feature size achievable with this new method is approximately 20 mu m, while the maximum equivalent gradient exceeds 40 mu m/mm. Based on these findings, this study proposes a novel approach to beam smoothing and shaping through the integration of multiple fabricated surfaces. Numerical simulations indicate that combining randomly structured surfaces generated by both linear and circular laser scanning paths can effectively achieve uniform beam smoothing.

Abstract We propose an evaluation approach based on spatial-frequency power spectral density of focal-spot-intensity relative deviation (PSDFRD), which corresponds to the spatial frequency distribution of squared focal-spot-intensity contrast, to quantify the effectiveness of beam smoothing techniques in laser-driven inertial confinement fusion (ICF). This approach enables assessment of smoothing effects that cannot be adequately distinguished by conventional metrics like contrast and fractional power above intensity (FOPAI). Beam smoothing techniques employed in this work include continuous phase plate (CPP), smoothing by spectral dispersion (SSD), and polarization smoothing (PS) with two implementations: birefringent wedge (BW) and spatially-random polarization control plate (SRPCP)). Focal spot intensity distributions were characterized for six beam smoothing configurations (CPP only, CPP+BW, CPP+SRPCP, CPP+SSD, CPP+BW+SSD, and CPP+SRPCP+SSD), with uniformity analyzed using the proposed method. CPP+PS (BW or SRPCP) configurations enhance intensity distribution and improve uniformity in the low-frequency range (0-0.002 μm -1 ), but introduce increased intensity and non-uniformity at high frequencies (0.050-0.070 μm -1 ). Compared to the one-dimensionally periodic smoothing characteristics of CPP+BW across spatial frequencies, CPP+SRPCP demonstrates superior smoothing uniformity across all spatial frequency domains. CPP+SSD reduces intensity distribution and improves uniformity across most frequencies, but it significantly increases both intensity and non-uniformity in the low-frequency region (0-0.001 μm -1 ). The CPP+PS (BW or SRPCP) +SSD not only mitigates elevated high-frequency intensity and non-uniformity inherent to the CPP+PS (BW or SRPCP) but also reduces low-frequency non-uniformity characteristic of CPP+SSD. Therefore, the combination of CPP, PS, and SSD exhibits a complementary smoothing effect.

The therapeutic radionuclide terbium-161 (161Tb) is a promising alternative to lutetium-177 (177Lu) for targeted radionuclide therapy, particularly for treating micrometastases. However, its clinical development is constrained by limited production capacity and the need for efficient separation from irradiated targets. This study developed a scalable, two-stage chromatographic process for producing no-carrier-added (n.c.a.) 161Tb, aiming to provide high-activity, high-purity material suitable for radiopharmaceutical development. High-purity n.c.a. [161Tb]TbCl₃ was obtained via sequential chromatography using a self-synthesized lanthanide (LN) resin and a commercial diglycolamide (DGA) resin. A single production batch yielded 42.38 ± 0.05

Residual stress constitutes an essential parameter for evaluating the operational reliability of welded components. While oscillating laser welding demonstrates notable benefits, including superior weld morphology, diminished porosity, optimized grain refinement, and augmented mechanical characteristics, its influence on residual stress distribution remains insufficiently characterized. This study develops a stress numerical model specifically for oscillating laser welding processes, demonstrating a coefficient of fitting degree greater than 90 %. Additionally, an equivalent fluid-structure interactions model is introduced, accounting for the convective heat transfer of the molten material caused by the laser beam's stirring effect. This model improves the fusion depth fitting to 97.1 %. Using this model, the evolution and distribution of residual stresses in oscillating laser welding are analyzed. The findings reveal that residual stresses are primarily concentrated at the top of the weld, with transverse and longitudinal residual stresses being predominant. Transverse stresses are mostly tensile, while longitudinal stresses are mainly compressive. Furthermore, the oscillating laser beam was found to be effective in reducing the area of high residual tensile stress distribution in the centre of the weld, where the longitudinal area of distribution was reduced by 3.3 %, and the transverse area of distribution was reduced by 7.3 %.

Surface and subsurface defects introduced in traditional mechanical polishing seriously influence the laser damage threshold of fused silica. As a non-contact processing technology, CO2 laser melt polishing could obtain smooth surface by healing surface defects and cracks. However, due to the non-uniformity of the thermal interaction, the mid- and high-spatial frequency errors of the polished optic are pretty high, which seriously reduces the surface quality and even causes light field modulation. In this work, the formation mechanism of the mid- and high-spatial frequency errors of fused silica polished by lasers was explored through temperature and fluid fields multi-physics coupling simulation. Then, the factors influencing the mid-and high-spatial frequency errors were explored. The results showed that the errors of the optic were greatly influenced by the laser scanning speed and track pitch. Then, an innovative polishing strategy was proposed by combining multi-layer high-speed polishing with single-layer low-speed polishing. The mid- and high-spatial frequency error was reduced from 47nm to 17.7nm and the high-spatial frequency error was reduced from 8.4nm to 1.5nm compared with the previous results. This work revealed the formation mechanism of the mid- and high-spatial frequency errors through multi-physics coupling simulation and effectively controlled the errors by using an innovative polishing strategy. It can offer both theoretical and experimental advice for the ultra-precision machining technique employed on fused silica.

We demonstrate a new polarization smoothing(PS)approach utilizing residual stress birefringence in fused silica to create a spatially random polarization control plate(SRPCP),thereby improving target illumination uniformity in inertial confinement fusion(ICF)laser systems.The fundamental operating mechanism and key fabrication techniques for the SRPCP are systematically developed and experimentally validated.The SRPCP converts a linearly polarized 3ω incident laser beam into an output beam with a spatially randomized polarization distribution.When combined with a continuous phase plate,the SRPCP effectively suppresses high-intensity speckles at all spatial frequencies in the focal spot.The proposed PS technique is specifically designed for high-fluence large-aperture laser systems,enabling novel polarization control regimes in laser-driven ICF.

Despite the widespread use of Ce-doped glass in laser systems within the radiation environment, its transient laser-induced damage dynamics are still not well understood. This study utilizes a dual perspective pump-probe technique to observe the transient damage progression of Ce-doped glasses under high-power UV laser irradiation. Glass composites containing 0.5 and 1.0 mol% CeO2 doping were tested for the high visible-light transparency, strong radiation resistance, and high laser damage thresholds. Three stages of damage were identified: (1) radial crack propagation, (2) transition to circumferential crack formation, and (3) expansion dominated by circumferential cracks. Furthermore, the plasma dynamics and shock waves resulting from air compression were analyzed. The influence of Ce-doping concentration on the damage dynamics was also discussed.

Fused silica optics (e.g., wedged focus lenses, continuous phase plate) with high-performance and accuracy are key components in laser-driven inertial confinement fusion (LD-ICF) facilities which deliver megajoule and petawatt lasers for fusion ignition. The LD-ICF necessitates the use of high-quality, large-aperture fused silica optics to control laser beams temporally, spatially, and spectrally, posing significant ultra-precision manufacturing challenges. When these fused silica optics are exposed to intense laser pulses, laser-induced surface damage (LISD) might generate and then escalate rapidly during subsequent laser shots. This has been a limiting factor in the promotion of output energy in LD-ICF. The root cause of LISD is surface/subsurface defects (SSD). Therefore, eradicating SSD is essential to reduce LISD initiations and repair them. In response to this issue, various techniques have been developed to enhance the laser damage resistance (LDR) of fused silica optics by inhibiting SSD and repairing LISD. Nevertheless, the actual LDR of these optics in practical applications is still significantly below the intrinsic thresholds of their raw materials. A comprehensive and in-depth review of LDR improvement techniques is necessary to provide references for manufacturing high-performance fused silica optics. This paper summarizes the development of cutting-edge manufacturing techniques used to enhance the LDR of fused silica optics. These techniques might introduce new damage precursors (such as redepositions and chemical structure defects), constraining further enhancements in the LDR of fused silica optics. These challenges and their solutions are discussed and analyzed emphatically, and the future trends of LDR improvement techniques are explored. This study aims to provide a foundation and guidance for manufacturing high-performance fused silica optics as well as other hard-brittle optics, thereby propelling the advancement of LD-ICF.

A time-resolved shadowgraphy and stress imaging system is used in this work to study the dynamic characteristics and evolution of the stress/stress waves, damage morphology and crack propagation during 355 nm laser-induced rear-surface damage and damage growth in fused silica. The relationship between the distribution of stress/stress waves and the magnitude of stress intensity and the damage, as well as the effects on the damage, especially on the crack propagation, were analyzed. The results show that the propagation of stress waves has a significant effect on the damage growth. Furthermore, the thermal aggregation effect and crack tip effect at the damage site also make the subsequent crack growth more rapid and intense, thus affecting the crack distribution and evolution. The intensity distribution during stress wave propagation also affects the variation of the length and depth of different types of cracks for damage growth, as well as leading to a change in the direction of propagation of the crack tip. The results provide experimental support for the further study of the physical mechanisms of stress/stress wave on damage.

The influences of Cr3C2 addition on phase formation, microstructures and mechanical properties of (Zr,Ti,Nb,Ta, Hf)C prepared from binary carbides mixtures by spark plasma sintering were studied. The introduction of 4/ 3 mol.% Cr3C2 significantly lowered the minimum temperature for uniform high-entropy phase (Zr,Ti,Nb,Ta,Hf) C from 2200 degrees C for to 1900 degrees C. The lower solubility limit of Cr in (Zr,Ti,Nb,Ta,Hf,Cr)C results in excessive Cr3C2-based carbides, which tends to segregate along grain boundaries at higher sintering temperatures while locate at triple junctions at lower sintering temperatures. High mechanical strength of 599 MPa were obtained when 4/ 3 mol.% Cr2C3 was added and sintered at 1900 degrees C. The fine grain size and Cr3C2-based carbides are responsible for the high mechanical properties. More Cr2C3 addition results in lower mechanical properties due to excessive Cr3C2-based carbides.

A two-dimensional coupled model of phase transition, heat transfer and vaporization ablation of laser-irradiated HgCdTe materials has been developed for the first time using finite element analysis to simulate the behavior and characteristics of melting, phase transition and ablation of HgCdTe materials irradiated by a COQ laser with a wavelength of 10.6 mu m at different laser powers. The results demonstrate that an increase in power density results in an exponential decrease in the time required for HgCdTe to reach the melting and gasification temperatures. The corresponding temperature points can be reached in the order of nanoseconds. During the heating phase, the increase in temperature results in a gradual enlargement of the melt pool in the ablation crater, with the minimum thickness of the melt pool occurring in the central region of the ablation. However, the diameter of the ablation crater tends to stabilize after the spot size is reached. An increase in power density results in a reduction in the size of the molten pool at the center of the ablation crater, while the size of the molten pool at the edges remains relatively constant. Once the laser irradiation ceases, the melt pool near the ablation crater's center is initially dissipated because of heat generated by the material's gasification process. In contrast, the melt pool at the periphery persists until the final stages of dissolution. The simulation results demonstrate that at a power density of 2.6 MW/cm2 , 2 , the ablation crater depth is approximately 12 mu m, which is enough to penetrate the HgCdTe layer of the detector. These results provide a foundation for further research on the damage mechanisms of HgCdTe detectors.

High-entropy (Ti0.2Nb0.2Ta0.2Hf0.2W0.2)Cx with different carbon vacancies were prepared from raw binary carbides in this study. The influences of stoichiometry, particle size of raw powder, and sintering temperature on phase formation, microstructure, and mechanical properties of (Ti0.2Nb0.2Ta0.2Hf0.2W0.2)Cx were systematically investigated. The results indicate that the introduction of carbon vacancies and using finer raw binary carbide powders can both significantly enhance the formation ability of single-phase composition with uniform elemental distributions. The formation of a high-entropy phase could enhance the Vicker’s hardness. The flexural strength is greatly influenced by the content of carbon vacancy, which is greatly detrimental to flexural strength. The fracture toughness is determined by both the content of carbon vacancies and the presence of secondary phases. By optimizing the content of carbon vacancies, particle size of raw powders, and sintering temperature, (Ti0.2Nb0.2Ta0.2Hf0.2W0.2)C shows super high flexural strength of 743 MPa and fracture toughness of 8.6 MPa m-1/2.

The properties of rare-earth (RE) monosilicates can be regulated by solid solution engineering based on the mixture rule. The combination and number of RE principals are critical factors for better performances. In the present study, four single-phase equimolar multicomponent RE-monosilicate solid solutions including (Dy1/3Er1/3Yb1/3)2SiO5, (Ho1/3Er1/3Yb1/3)2SiO5, (Y1/4Er1/4Tm1/4Lu1/4)2SiO5 and (Dy1/4Er1/4Tm1/4Yb1/4)2SiO5 were synthesized by solid-state reaction and hot-pressing method. The microstructures, thermal and mechanical properties, and corrosion resistance to high-temperature water vapor were systematically investigated. Compared to the single-principal and ternary RE-monosilicates, the quaternary RE-monosilicates exhibited lower thermal conductivity of 1.32 Wm-1K-1 at 400 oC, matched thermal expansion coefficients (3.3 × 10−6/oC ∼ 5.8 × 10−6/oC from 200 oC to 1000 oC) with SiC, and much lower weight loss during water vapor corrosion. The results indicate that the increase of the RE element number can promote the grain growth, lower the thermal conductivity and thermal expansion coefficient, and enhance corrosion resistance.

CO 2 laser polishing process is a highly effective way for enhancing the surface quality and laser-induced damage threshold of fused silica optics. Nevertheless, due to the thermal history and spatial gradient of the thermodynamic temperature, the heat-affected zones can be formed unevenly on the surface with an increased fictive temperature, which causes the material densification and residual stress. In this work, a 3D model of structural relaxation coupled with temperature and flow fields was innovatively established to explore the role of fictive temperature distribution involved in CO 2 laser polishing of fused silica. The Raman spectrum was applied to verify this model. Subsequently, the impacts of laser beam power, scanning speed, track overlapping, substrate temperature on the fictive temperature were discussed. The results indicate that decreasing the scanning speed and increasing the substrate temperature can decrease the fictive temperature. Additionally, a higher track overlapping can reduce the height of the fictive temperature " tool mark " . Moreover, an optimization strategy based on laser beam scanning speed was proposed based on the uniform distribution of fictive temperature. The depth difference of the heat-affected zones was reduced from 164.26 mu m to 31.74 mu m. This work could be used to quantitatively predict the 3D fictive temperature distribution and proposed an optimization strategy based on scanning speed to suppress the non-uniformity of fictive temperature distribution, which can provide significant theoretical guidance for CO 2 laser polishing technology of fused silica optics.

BACKGROUND:The radionuclide-labeled bevacizumab (BV) is a potential therapeutic approach for vascular endothelial growth factor overexpressed tumors. Because of its large molecular weight, BV is cleared slowly in vivo , which caused damage to healthy tissues and organs. On account of this situation, using the pretargeting strategy with DNA/RNA analogs, such as peptide nucleic acid (PNA), is an effective way of treating solid tumors. METHODS:The BV-PNA conjugate (BV-PNA-1) was injected intravenously as the pretargeted probe, which was specifically accumulated in a solid tumor and gradually metabolically cleared. Then the [ 177 Lu]Lu-labeled complementary PNA strand ([ 177 Lu]Lu-PNA-2) as the second probe was injected, and bound with BV-PNA-1 by the base complementary pairing. In this study, the BV-based PNA-mediated pretargeting strategy was systematically studied, including stability of probes, specific binding ability, biodistribution in animal model, evaluation of single photon emission computed tomography/computed tomography imaging, and therapeutic effect. RESULTS:Compared with group A ([ 177 Lu]Lu-BV), the group B (BV-PNA-1 + [ 177 Lu]Lu-PNA-2) showed lower blood radiotoxicity (22.55 ±1.62 vs. 5.18 ± 0.40%, %ID/g, P < 0.05), and similar accumulation of radioactivity in tumor (5.32 ± 0.66 vs. 6.68 ± 0.79%, %ID/g, P > 0.05). Correspondingly, there was no significant difference in therapeutic effect between groups A and B. CONCLUSION:The PNA-mediated pretargeting strategy could increase the tumor-to-blood ratio, thereby reducing the damage to normal tissues, while having a similar therapeutic effect to solid tumor. All the experiments in this study showed the potential and effectiveness of pretargeting radioimmunotherapy.