112 research outputs found
A Central Consciousness at Work Beneath the Surface Artlessness: Narrative Strategies in “Tristram Shandy”
Get PDF‘The Life and Opinions of Tristram Shandy, Gentleman’ (hereafter shortened to “Tristram Shandy”) is a unique novel written by British author Laurence Sterne in the eighteenth century. While Sterne’s contemporary readers may have conflicting viewpoints about the artistic value of “Tristram Shandy” because of its surface artlessness and chaos, readers today in the contexts of such twentieth-century critical theories as postmodernism, existentialism, and deconstruction, find it congenial and more intriguing. I argue that despite the apparent chaos of this novel, the author-narrator Tristram is a central consciousness that holds the whole work together. And I believe Sterne narrates his story in such a peculiar way in conformity to his own perception of the outside world. Specifically, this paper aims to explore the inventive narrative strategies employed in Sterne’s “Tristram Shandy” in the three aspects of narrative structure, time-shifting technique and self-conscious narrator. Amazingly, “Tristram Shandy” presents a wholly new notion of creative writing, one that goes beyond its time, and has unbreakable connection with twentieth-century literature.</jats:p
Characteristics and Mechanism of Upper Airway Collapse Revealed by Dynamic MRI During Natural Sleep in Patients with Severe Obstructive Sleep Apnea
No full textYuqi Li,1,2,* Changjin Ji,1,2,* Weiao Sun,1,2 Huahui Xiong,1,2 Zheng Li,3 Xiaoqing Huang,1,2 Tingting Fan,1,2 Junfang Xian,3 Yaqi Huang1,2 1School of Biomedical Engineering, Capital Medical University, Beijing, People’s Republic of China; 2Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing, People’s Republic of China; 3Department of Radiology, Beijing Tongren Hospital, Capital Medical University, Beijing, People’s Republic of China*These authors contributed equally to this workCorrespondence: Yaqi Huang, School of Biomedical Engineering, Capital Medical University, Beijing, People’s Republic of China, Tel +86-10-83911809, Email [email protected] Junfang Xian, Department of Radiology, Beijing Tongren Hospital, Capital Medical University, Beijing, People’s Republic of China, Email [email protected]: Upper airway collapse during sleep in patients with obstructive sleep apnea (OSA) is a complex and dynamic phenomenon. By observing and analyzing the dynamic changes in the upper airway and its surrounding tissues during airway obstruction, we aim to reveal dynamic characteristics in different obstruction patterns, and the relationship between anatomical features during normal breathing and dynamic characteristics of airway obstruction.Patients and Methods: Dynamic MRI was performed in 23 male patients (age range 26– 63) with severe OSA diagnosed by overnight polysomnography, and obstruction events were identified from their images. Dynamic changes in parameters of the upper airway and surrounding tissues were measured to assess the key characteristics in different obstruction patterns.Results: We categorized airway obstruction into four types based on the obstruction location and motion characteristics of tissues during collapse, and detailed the alterations in the airway and surrounding tissues under each obstruction pattern. In all 112 obstruction events extracted from the dynamic images of 23 patients, type A (retropalatal obstruction caused by the soft palate separated from the tongue), BI, BII (both retropalatal obstructions caused by the soft palate attached to the tongue, and C (retropalatal and retroglossal obstruction caused by the soft palate and the tongue), accounted for 28.6%, 44.6%, 12.5%, and 14.3% respectively. In severe OSA patients with tongue and palatal obstruction related to type B or C, the more posterior hyoid position, shorter distance between tongue and uvula, and wider retropalatal space, the larger the tongue displacement and deformation during collapse, and the greater the reduction in airway space.Conclusion: There are multiple airway obstruction patterns, each with its own anatomical characteristics and behaviors during collapse. Hyoid position, tongue and uvula distance, and retropalatal space play an important role in airway collapse and should be paid more attention in the treatment of OSA.Keywords: airway obstruction patterns, obstruction location, tissue motion characteristics, hyoid position, retropalatal spac
Impact-Angle Constraint Guidance and Control Strategies Based on Deep Reinforcement Learning
No full textIn this study, two different impact-angle-constrained guidance and control strategies using deep reinforcement learning (DRL) are proposed. The proposed strategies are based on the dual-loop and integrated guidance and control types. To address comprehensive flying object dynamics and the control mechanism, a Markov decision process is used to solve the guidance and control problem, and a real-time impact-angle error in the state vector is used to improve the model applicability. In addition, a reasonable reward mechanism is designed based on the state component which reduces both the miss distance and the impact-angle error and solves the problem of sparse rewards in DRL. Further, to overcome the negative effects of unbounded distributions on bounded action spaces, a Beta distribution is used instead of a Gaussian distribution in the proximal policy optimization algorithm for policy sampling. The state initialization is then realized using a sampling method adjusted to engineering backgrounds, and the control strategy is adapted to a wide range of operational scenarios with different impact angles. Simulation and Monte Carlo experiments in various scenarios show that, compared with other methods mentioned in the experiment in this paper, the proposed DRL strategy has smaller impact-angle errors and miss distance, which demonstrates the method’s effectiveness, applicability, and robustness
Notice of Retraction: Empirical research of talent growth platform based on science of personnel
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Aerobic oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran on supported vanadium oxide catalysts: Structural effect and reaction mechanism
No full textThe structure-activity relationship and reaction mechanism for selective oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF) in toluene were studied on vanadium oxide domains on TiO2, Al2O3, Nb2O5, ZrO2, and MgO and with a wide range of VOx surface densities. The structures of these catalysts were characterized by X-ray diffraction (XRD), diffuse reflectance UV-vis spectroscopy (UV-vis DRS), and Raman spectroscopy, and their reducibility was probed by H-2-temperature programmed reduction. The structures of the VOx domains evolved from monovanadate to polyvanadate structures with increasing the VOx surface densities, and finally to crystalline V2O5 clusters at surface densities above one-monolayer capacity. Within one-monolayer capacity, higher VOx surface densities and more reducible supports led to higher reducibility and reactivity of the VOx domains. The support surfaces covered with polyvanadates and V2O5 clusters and the supports with acidity favored the formation of DFF. The correlation between the reducibility and reactivity, together with the kinetic studies, suggests that the HMF oxidation to DFF proceeds via the redox mechanism involving the V5+/V4+ redox cycles and the reoxidation of V4+ to V5+ by O-2 as the rate-determining step. These results may provide guidance for the design of more efficient catalysts for the HMF oxidation to synthesize DFF.Chemistry, MultidisciplinarySCI(E)18ARTICLE3765-7778
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