分类： 天文学 >> 天文仪器与技术 提交时间： 2024-09-30 合作期刊: 《天文技术与仪器（英文）》
摘要： A time and frequency system is a critical component of Very Long Baseline Interferometry (VLBI) stations, providing stable and reliable standards that directly impact data processing quality. At the Tianma 65 m radio telescope(TMRT), this system has been meticulously designed to ensure long-term reliability and high performance. It incorporates high-performance hydrogen atomic clocks, high-precision time standards, automatic signal switching, and robust system software. This comprehensive approach has enabled the system to achieve long-term reliable operation, successfully supporting both major national engineering tasks and daily scientific observations. The effectiveness of the system is evidenced by its consistent delivery of the precision and stability required for radio astronomy. This article provides an in-depth exploration of the design and operation of the time and frequency system at the Tianma 65 m telescope, examining various aspects of its architecture, implementation, and performance. By sharing these insights, we aim to contribute knowledge that could benefit similar systems at other VLBI stations, greatly advancing radio astronomy infrastructure.
分类： 心理学 >> 发展心理学 提交时间： 2024-01-16
摘要： Objective: To test the reliability and validity of the short version of the Child Abuse Self Report Scale (CASRS‑12) in Chinese college students. Methods: A total of 980 college students were investigated, of whom 418 were investigated for the first time, and only filled in the CASRS‑12. In the second survey, 514 subjects filled in the CASRS‑12, general anxiety scale, self-esteem scale and subjective well-being scale. Results: Each item of the CASRS‑12 had a good discrimination. Both exploratory and confirmatory factor analysis confirmed the four-factor model of the scale, and the fitness indicators were 2/df=4.18，RMSEA=0.079，CFI=0.95，TLI=0.94，IFI=0.95，NFI=0.94. The cumulative explained variance is 76.05%. The internal consistency reliability and test-retest reliability of the scale were 0.86 and 0.74 respectively. The CASRS‑12 was positively correlated with depression scale (r=0.42, p
分类： 物理学 >> 核物理学 提交时间： 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要： The reliability of radiotherapy was evaluated and effective approaches were obtained in order to improve radiotherapy quality by using the Probabilistic Safety Assessment (PSA) method. This study investigated the feasibility of the PSA method being applied to radiotherapy through Image-guided Radiotherapy (IGRT) and chest tumor irradiation. A fault tree has been constructed after analyzing causal relationship of the events. After calculating RiskA, a total inaccuracy radiotherapy probability and the importance of all base events were obtained. The probability of inaccurate radiotherapy was 2.87%. Under the condition that the target delineation was perfectly right, the accuracy of radiotherapy significantly improved. With the calculation without Cone-beam Computed Tomography (CBCT) being corrected before irradiation, the accuracy significantly decreased. The most important events were connected with the human factor. Improving human technical level could enhance radiotherapy quality control efficiently.
分类： 心理学 >> 心理统计 提交时间： 2018-12-07
摘要： Human brain mapping (HBM) is increasingly becoming a multi-disciplinary field where some scientific issues are fundamental for all scientists and applications of using the technology to investigate individual differences. Reliability represents a significant issue for all scientific fields and has particularly been overlooked for decades by the HBM field [1]. Meanwhile, recent advances in open science have offered the field big data for developing novel methodological frameworks as well as performing large-scale investigations of the brain-mind associations based upon the individual differences assessed with HBM [2]. A systematic investigation of reliability seems still far behind these HBM developments. It is critical that reliability is evaluated ahead of these applications, motivating the current commentary on delineation of the anatomy of reliability for future HBM.
分类： 心理学 >> 应用心理学 提交时间： 2017-11-06
Lei Gao
Lijun Bai
Yuchen Zhang
Xi-jian Dai
Rana Netra
Youjiang Min
Fuqing燴hou
Honghan Gong
Ming Zhang
Yijun Liu
摘要： Recent studies have indicated that sleep deprivation (SD) alters intrinsic low-frequency connectivity in the resting brain, mainly focusing on the default mode network (DMN) and its anticorrelated network (ACN). These networks hold key functions in segregating internally and externally directed awareness. However, far less attention has been paid to investigation of the altered amplitude of these low-frequency fluctuations (ALFF) at the whole-brain level and more importantly by what extent the sleep-deprived resting brain pattern can be reproducible and predict individual behavioral performance. The aim of this study was to characterize more clearly the influence of sleep on the whole brain level of ALFF changes and its relation with the performance of a lexical decision task in the sleep deprivation. Sixteen healthy participants underwent fMRI three times: once after a normal night of sleep in the rested wakefulness (RW) state and two following approximately 24 h of total SD separated by an interval of two weeks (SD1 and SD2). Our behavioral results showed that sleep stabilizes performance whereas two sleep deprivation even at an interval of two weeks consistently deteriorates it. Sleep deprivation attenuated the ALFF mainly in the bilateral orbitofrontal cortex (OFC), bilateral dorsolateral prefrontal cortex (DLPFC) and right inferior parietal lobule (IPL). By contrast, the enhanced ALFF emerged in the left sensorimotor cortex (SMA), visual cortex and left fusiform gyrus. Conjunction analysis of SD1 and SD2 versus the control maps and voxel-wise ICC analysis revealed that these SD induced ALFF changes showed a significantly high reliability (ICC＞0.5). Particularly, the attenuation of the right IPL presents a significant negative relation with the behavior performance and can be reproducible for two SD at an interval of two weeks. Our results suggest that ALFF is a stable measure in study of SD, and the right IPL may represent a stable biomarker that responds to sleep loss.
分类： 核科学技术 >> 核材料与工艺技术 提交时间： 2023-05-31
摘要： The nuclear fuel assembly is the core component of a nuclear reactor. In a pressurized water reactor fuel assembly, the top-connection structure connects the top nozzle to the guide thimble. Its performance reliability is essential for the stability of the nuclear fuel assembly. In this study, an assembly-oriented reliability analysis method for top-connection structures is presented by establishing an assembly-oriented top-connection structure parameter modeling method and a nonlinear contact gap and penetration correction method. A reliability model of the top-connection assembly structure, including multiple stochastic design variables, was constructed, and the overall reliability of the top-connection assembly structure was obtained via a Kriging model and Monte Carlo simulation. The acquired experimental data were consistent with real-world failure conditions, which verified the practicability and feasibility of the reliability analysis method proposed in this study.
分类： 管理学 >> 管理学其他学科 提交时间： 2022-11-23 合作期刊: 《2022年第三届传播、创新和经济管理国际研讨会》
摘要： This paper focuses on the effect of online comment leader phenomenon on product marketing in the era of new media, explores the influence of multiple information sources and credibility of information sources on consumers' cognition and purchase intention. Through questionnaire survey and data analysis, this study found that online comment leaders generally have high credibility and can exert certain influence on both first-time consumers and non-first-time consumers. In the presence of multiple information sources, the influence of online comment leaders on consumers tends to depend on the quantity rather than the content. This research has certain significance for the development of product marketing means of network platform.
分类： 心理学 >> 认知心理学 提交时间： 2024-05-31
摘要： The development of attentional functions is a fundamental issue of human cognitive development, but the available evidence for its developmental trajectory is inconsistent due to the diversity and low reliability of measurement paradigms. The study examined the development of attentional functions and attentional collaborations in 281 Chinese primary school children (109 girls, 5.98-13.24 years old) using the self-designed High Reliability-Composite Attention Test. Results showed that the executive control continued to develop prior to the age of 10. It further contributed to the linear development of attentional collaborations. Each of these scores exhibited a split-half reliability exceeding 0.82. Therefore, we effectively demonstrated a mechanism for attentional development that revolves around executive control.
分类： 生物学 >> 生物物理学 >> 神经科学 提交时间： 2016-05-11
Zou, Qihong
Gao, Jia-Hong
Miao, Xinyuan
Liu, Dapeng
Zhuo, Yan
Wang, Danny J. J.
Gao, Jia-Hong
Gao, Jia-Hong
摘要： Blood oxygenation level dependent (BOLD) and arterial spin labeling (ASL) are two predominant resting-state fMRI techniques in mapping spontaneous brain activities. At single voxel level, cerebral blood flow (CBF) measured by ASL and amplitude of low frequency fluctuations (ALFF) of BOLD have been recognized as useful indices to characterize brain function in health and disease. However, no study has directly compared the test-retest reliability between BOLD and CBF contrasts on the same group of subjects at single voxel level. Moreover, both eyes-open and eyes-closed conditions have been employed as resting states, but it is still not clear which state is more reliable. Here we collected BOLD and ASL data during eyes-open and eyes-closed states across three scanning visits on twenty-two healthy young subjects. CBF-mean, BOLD-and CBF-ALFF were computed to characterize corresponding brain activities at single voxel level. Seed-based functional connectivity (FC) with the posterior cingulate cortex (PCC) was further calculated for both BOLD and CBF data. Intra-class correlation was used as the index of long-term reliability between visits 1 and 2 (two months apart) and short-term reliability between visits 2 and 3 (on the same day). Both short-and long-term reliabilities for CBF-mean and BOLD-ALFF were high, but were lower for CBF-ALFF, BOLD-and CBF-FC in both eyes-open and eyes-closed states. Direct comparisons showed that brain regions with the highest reliability of CBF-mean were mainly in the gray matter. The reliability of CBF-ALFF and BOLD-FC was lower than that of BOLD-ALFF, and the reliability of CBF-FC was lower than those of both CBF-ALFF and BOLD-FC. Furthermore, we observed that reliabilities of the eyes-open state were higher than those of the eyes-closed state for both imaging contrasts, though the effect size was small. Voxel-wise comparisons demonstrated that the long-term reliability of BOLD-ALFF was significantly higher with eyes open in the visual system, and both the short-and long-term reliability of BOLD-FC was slightly higher with eyes open in the default mode network. Moreover, we showed that denoising decreased the reliability of both ALFF and FC of both BOLD and ASL contrasts. In conclusion, our results indicated that CBF-mean and BOLD-ALFF could both be used as reliable indices for characterizing resting-state brain activities at single voxel level and recommended the eyes-open state for resting-state studies, especially for those targeting the visual system and default mode network. (C) 2015 Elsevier Inc. All rights reserved.
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