2,929 research outputs found

    Period halving of Persistent Currents in Mesoscopic Mobius ladders

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    We investigate the period halving of persistent currents(PCs) of non-interacting electrons in isolated mesoscopic M\"{o}bius ladders without disorder, pierced by Aharonov-Bhom flux. The mechanisms of the period halving effect depend on the parity of the number of electrons as well as on the interchain hopping. Although the data of PCs in mesoscopic systems are sample-specific, some simple rules are found in the canonical ensemble average, such as all the odd harmonics of the PCs disappear, and the signals of even harmonics are non-negative. {PACS number(s): 73.23.Ra, 73.23.-b, 68.65.-k}Comment: 6 Pages with 3 EPS figure

    The relationship between marital adjustment and personality characteristics, medical coping style of infertile patients

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    目的  探讨不孕不育患者婚姻调适状况与人格特征和医学应对方式的关系,为临床开展心理健康干预提供依据。方法  选取2012年8月—2015年1月某三级甲等医院生殖医学中心治疗的156例已婚不孕不育症患者。采用艾森克人格问卷表(EPQ)、Locke-Wollance婚姻调适测定量表和医学应对问卷(MCMQ),对患者进行调查,分别测评患者婚姻调适状况、人格特征和医学应对方式及其相关性。结果  患者婚姻调适状况与EPQ的P、N及MCMQ屈服呈显著负相关,与EPQ 的E和MCMQ面对则呈显著正相关;EPQ的P、N与MCMQ面对呈负相关,与MCMQ的屈服呈正相关;EPQ的E则与MCMQ面对呈显著正相关。EPQ的P、E、N和MCMQ面对、屈服在婚姻调适状况高中低分组中的比较,差异均有统计学意义(均P<0.01)。多元逐步回归分析:面对、回避,屈服及精神质(P)等4个因素共解释了不孕不育症患者婚姻调适总变异的26.4%。结论  人格特征、医学应对方式是影响不孕不育症患者婚姻调适的重要因素。Objective: To explore the relationship between marital adjustment and personality characteristics and coping styles of patients with infertility, and to provide evidence for clinical intervention. Methods: A total of 156 patients with infertility were selected from August 2012 to January 2015 in a grade a hospital of reproductive medicine center. This research is a cross - sectional survey. The Eysenck Personality Questionnaire (EPQ), Locke-Wollance marital adjustment test scale and Medical Coping Questionnaire (MCMQ), were investigated, respectively, to evaluate the patient status, marital adjustment and personality characteristics and coping style and their relationship. Results: Patients marital adjustment status and EPQ P, N and MCMQ yield was significantly negative correlated, and EPQ E and MCMQ was significantly positively related; EPQ P, N and MCMQ showed a negative correlation, and MCMQ yield positively correlated; EPQ E, and MCMQ face was significantly positively related, EPQ P, E, N and MCMQ, yield in the marital adjustment the conditions of grouping, the differences were statistically significant (all P < 0.01). Multiple stepwise regression analysis: 4 factors, such as confrontation, avoidance, yield and psychoticism (P), were used to explain the total variation of the adjustment of marriage in infertile patients (26.4%). Conclusion: Personality characteristics, medical coping styles are the important factors influencing the marital adjustment for infertility patients

    A comparative study of the dynamics of a three-disk dynamo system with and without time delay

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    The disk dynamo plays an important role in studying the geodynamo and much research works have been devoted to the understanding of dynamo dynamics. This paper further investigates an extended disk dynamo system having three coupled conducting disks and incorporates the interaction-induced time delay in the dynamic governing equations. By carrying out a comparative analysis, the dynamic behaviors of the coupled three-disk dynamo system with and without time delay are studied to explore novel and complex nonlinear dynamic phenomena in the coupled delayed dynamo system. It is found that the double Hopf bifurcations can be induced in the time-delayed dynamo system. Three different topological structures of the unfolding are obtained under different time delays. Accordingly, it is shown that the novel dynamic behaviors, including quasi-periodic torus, three-dimensional torus and the coexistence of multiple attractors, can appear in the time-delayed dynamo system. Furthermore, by performing the continuation analysis on the periodic orbit generated from the Hopf bifurcation of equilibrium, some new coexistence patterns, e.g., the coexistence of periodic orbits and chaos, the coexistence of quasi-periodic orbits and chaos, are observed in the dynamo system with time delay. Based on the obtained results, it is believed that the inclusion of time delay in the modelling of the three-disk dynamo system is necessary and meaningful for developing an in-depth understanding of dynamo dynamics. Finally, the results of theoretical analyses are verified by the numerical simulations

    Large Language Models for Information Retrieval: A Survey

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    As a primary means of information acquisition, information retrieval (IR) systems, such as search engines, have integrated themselves into our daily lives. These systems also serve as components of dialogue, question-answering, and recommender systems. The trajectory of IR has evolved dynamically from its origins in term-based methods to its integration with advanced neural models. While the neural models excel at capturing complex contextual signals and semantic nuances, thereby reshaping the IR landscape, they still face challenges such as data scarcity, interpretability, and the generation of contextually plausible yet potentially inaccurate responses. This evolution requires a combination of both traditional methods (such as term-based sparse retrieval methods with rapid response) and modern neural architectures (such as language models with powerful language understanding capacity). Meanwhile, the emergence of large language models (LLMs), typified by ChatGPT and GPT-4, has revolutionized natural language processing due to their remarkable language understanding, generation, generalization, and reasoning abilities. Consequently, recent research has sought to leverage LLMs to improve IR systems. Given the rapid evolution of this research trajectory, it is necessary to consolidate existing methodologies and provide nuanced insights through a comprehensive overview. In this survey, we delve into the confluence of LLMs and IR systems, including crucial aspects such as query rewriters, retrievers, rerankers, and readers. Additionally, we explore promising directions within this expanding field
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