分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： It is a formidable challenge to simultaneously achieve wide gamut, high resolution, high-speed while low-cost manufacturability, long-term stability, and viewing-angle independence in structural colors for practical applications. The conventional nanofabrication techniques fail to match the requirement in low-cost, large-scale and flexible manufacturing. Processing by ultrashort lasers can achieve extremely high throughput while suffering from a narrow gamut of 15% sRGB or angle-dependent colors. Here, we demonstrate an all-in-one solution for ultrafast laser-produced structural colors on ultrathin hybrid films that comprise an absorbent TiAlN layer coating on a metallic TiN layer. Under pulsed laser irradiation, the absorption behaviors of the TiAlN-TiN hybrid films are tailored by photothermal-induced oxidation on the topmost TiAlN. The oxidized films exhibit double-resonance absorption, which is attributed to the non-trivial phase shifts both at the oxide-TiAlN interface, and at the TiAlN-TiN interface. By varying the accumulated laser fluence to modulate the oxidation depth, an unprecedented large gamut of 90% sRGB is obtained. Our highly reproducible printing technique manifests angle-insensitive colors the variation of Hue is <0.14pi when viewing angles changing from 6 to 60. The full-color printing speed reaches to 1.4 cm2/s and the highest printing resolution exceeds 25000 dpi. The durability of the laser-printed colors is confirmed by fastness examination, including salt fog, double-85, light bleaching, and adhesion tests. These features render our technique to be competitive for high-throughput industrial applications.
分类： 物理学 >> 核物理学 提交时间： 2025-03-04
摘要： The rapid development of accelerators has accelerated the clinical application of BNCT. The beam moderation and shaping assembly (BSA) in accelerator-based boron neutron capture therapy (AB-BNCT) device is crucial for the production of epithermal neutrons. Based on the 10 MeV proton beam generated by accelerator, the BSA was designed using the Monte Carlo simulation method, and the BSA design scheme was verified by the dose distribution of the epithermal neutron beam in the human head model. The results show that when the accelerator current intensity reaches 2.2 mA, the designed BSA meets the requirements of the IAEA for BNCT treatment beams. In the clinical dose estimation, the advantage depth can reach 11.2 cm, and the advantage ratio is 5. In addition, the tumor boron physical dose can reach 16 Gy within the treatment time when the normal tissue reaches the tolerance dose. The above results show that the BSA design scheme given for the 10 MeV proton beam is very reliable, and the BNCT device according to this scheme has good clinical treatment effect.
分类： 物理学 >> 核物理学 提交时间： 2025-04-01
摘要： Determining the release source position and quantity is crucial for evaluating the consequences of atmospheric radionuclide release events, with the Bayesian method serving as the primary tool for source inversion. Reducing the impact of input data errors on inversion uncertainty and improving computational efficiency are key to developing robust and efficient inversion algorithms. To address these challenges, a spatiotemporal trajectory prior (STP) distribution was developed to effectively mitigate the influence of measurement and simulation errors on inversion results without increasing computational costs, thereby enhancing the robustness and accuracy of the inversion process. Additionally, a joint adaptive Markov Chain Monte Carlo (MCMC) sampling method was introduced, integrating the traditional parallel tempering (PT) algorithm with a novel joint adaptive transition proposal (JATP) algorithm to accelerate inversion calculations. The proposed methods were optimized and validated using data from the first release of the European Tracer Experiment (ETEX-I). After determining the hyperparameters, the JATP algorithm consistently maintained the sampling process near the theoretically optimal acceptance rate of 0.234. The PT algorithm, utilizing an optimized temperature schedule, achieved a 3.3-fold improvement in sampling efficiency compared to single-chain sampling. Under bootstrap statistical comparison, the method reduced the relative error of position, relative error of release quantity, and combined relative error by 25.9%, 27.7%, and 27.8%, compared to the traditional uniform prior method, respectively. And the deviation of the estimated and true source position is within 0.25˚. The results demonstrate the accuracy and effectiveness of our method.
分类： 物理学 >> 核物理学 提交时间： 2025-01-02
摘要： Determining the release source position and quantity is crucial for evaluating the consequences of atmospheric radionuclide release events, with the Bayesian method serving as the primary tool for source inversion. Reducing the impact of input data errors on inversion uncertainty and improving computational efficiency are key to developing robust and efficient inversion algorithms. To address these challenges, we developed a spatiotemporal trajectory prior (STP) distribution that effectively mitigates the influence of measurement and simulation errors on inversion results without increasing computational costs, thereby enhancing the robustness and accuracy of the inversion process. Additionally, we introduced a joint adaptive Markov Chain Monte Carlo (MCMC) sampling method that integrates the traditional parallel tempering (PT) algorithm with a novel joint adaptive transition proposal (JATP) algorithm to accelerate inversion calculations. The proposed methods were optimized and validated using data from the first release of the European Tracer Experiment (ETEX-I). After determining the hyperparameters, the JATP algorithm consistently maintained the sampling process near the theoretically optimal acceptance rate of 0.234. The PT algorithm, utilizing an optimized temperature schedule, achieved a 2.89-fold improvement in sampling efficiency compared to single-chain sampling. Under bootstrap statistical comparison, the method reduced the relative error of position, relative error of release quantity, and total relative error by 25.9%, 27.7%, and 27.8%, compared to the traditional uniform prior method, respectively. And the deviation of the estimated and true source position is within 0.25˚. The results demonstrate the accuracy and effectiveness of our method.
分类： 心理学 >> 认知心理学 分类： 心理学 >> 心理学其他学科 提交时间： 2020-03-05
Chen, Li-Zhen
Yuan, Xinru
Zhang, Yuanchao
Zhang, Shu
Zou, Liye
Yang, Lin
Chang, Yu-Kai
Xia, Qixin
Wang, Yiqun
Wei, Gao-Xia
摘要： Objective: To investigate the effect of long-term Tai Chi Chuan (TCC) practice on practitioners’ brain functional specialization compare with the TCC novices. Methods: 22 TCC practitioners (52.4 ± 6.8 years; 7 males; educated years:12.18 ± 3.03 years) and 18 healthy controls (54.8 ± 6.8 years; 8 males; education years:11.78 ± 2.90 years) matched by age, sex, and education were enrolled. Participants underwent functional magnetic resonance imaging (fMRI) scanning and cognitive test to measure the differences in functional specialization and cognitive function. Functional specialization was evaluated by voxel-mirrored homotopic connectivity (VMHC) method. Results: Lower middle frontal gyrus (MFG) VMHC in TCC practitioners compared to controls. For TCC practitioners, the longer they practice, the lower their VMHC in precentral and precuneus. TCC practitioners showed better cognition performance. Limitations: Relatively small sample size. Conclusions: Changed VMHC indicated that TCC practice could enhance functional specialization in the middle frontal cortex of practitioners, which may be associated with higher-order cognitive ability.
分类： 物理学 >> 核物理学 提交时间： 2025-03-18
Gao, Mr. Huaizhong
Zheng, Dr. Xutao
Wen, Dr. Jiaxing
Wang, Mr. Qidong
Ma, Mr. Ge
Zhang, Miss Yuge
Pan, Mr. Xiaofan
Li, Mr. Chen
Zeng, Prof. Ming
Yu, Mr. Minghai
Wu, Mr. Sixin
Yang, Miss Yue
Zhao, Prof. Zongqing
Liu, Prof. Liye
Yi, Prof. Hengguan
Xia, Prof. Sanqiang
摘要： Semiconductor pixel detectors are widely used in various applications, many of which require sustained stability of the detector performance over extended periods of operations. However, the presence of irreversible and temporary degradations can impact the detector performance during prolonged use. Thus, continual monitoring of the detector performance that can be affected by degradation effects become necessary. This paper presents a cost-effective examination procedure for real-time monitoring and regular inspections of pixel detectors during prolonged operations. The real-time monitoring method monitors the charge drifting process without introducing additional background by utilizing the cosmic muons to detect temporary effects caused by shifts in operating conditions such as ambient temperature. On the other hand, the offline inspection regularly evaluates the per-pixel spectral characteristics including baseline and gain using simple radioactive sources to evaluate the level of irreversible degradation. The monitoring procedure is validated on a Timepix3 detector equipped with a CdTe sensor which proves its effectiveness.
分类： 物理学 >> 核物理学 提交时间： 2025-02-11
Gao, Mr. Huaizhong
Zheng, Dr. Xutao
Wen, Dr. Jiaxing
Wang, Mr. Qidong
Ma, Mr. Ge
Zhang, Miss Yuge
Pan, Mr. Xiaofan
Li, Mr. Chen
Zeng, Prof. Ming
Yu, Mr. Minghai
Wu, Mr. Sixin
Yang, Miss Yue
Zhao, Prof. Zongqing
Liu, Prof. Liye
Yi, Prof. Hengguan
Xia, Prof. Sanqiang
摘要： Semiconductor pixel detectors are widely used in various applications, many of which require sustained stability of the detector performance over extended periods of operations. However, the presence of irreversible and temporary degradations can impact the detector performance during prolonged use. Thus, continual monitoring of the detector performance that can be affected by degradation effects become necessary. This paper presents a cost-effective examination procedure for real-time monitoring and regular inspections of pixel detectors during prolonged operations. The real-time monitoring method monitors the charge drifting process without introducing additional background by utilizing the cosmic muons to detect temporary effects caused by shifts in operating conditions such as ambient temperature. On the other hand, the offline inspection regularly evaluates the per-pixel spectral characteristics including baseline and gain using simple radioactive sources to evaluate the level of irreversible degradation. The monitoring procedure is validated on a Timepix3 detector equipped with a CdTe sensor which proves its effectiveness.
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