155 research outputs found
Ji tai 23Na 87Rb fen zi de ji xing chao leng qi ti
No full textPh.D.This thesis describes the creation and collisional investigations of a high density sample of ultracold ground-state dipolar ²³Na⁸⁷Rb molecules. These molecules are produced by transferring weakly-bound Feshbach molecules to the ground state through a two-photon Raman process. To this end, an ultrastable and narrow linewidth Raman laser system is constructed by locking two diode lasers to a dual-wavelength coated high-finesse optical cavity. After identifying the two-photon pathway, a Stimulated Raman adiabatic passage with efficiency up to 93% is achieved, which allows us to produce a sample of absolute ground-state ²³Na⁸⁷Rb molecules with density as high as 6×10¹¹ cm⁻³. An effective electric dipole moment over 1 Debye, the largest ever achieved in ultracold molecules, is also demonstrated by applying a static electric field.Although the absolute ground-state ²³Na⁸⁷Rb molecules are chemically stable, an unexpected fast two-body loss is observed. Thus, collisions of the molecules prepared to different internal states, which is achieved by combining the high-resolution two-photon Raman process with extra microwave pulses, are investigated. Loss rates of the ground-state molecules with different dipolar interaction strength are also measured. These results pave the way toward the investigations of ultracold gases with strong dipolar interactions本論文介紹了高密度基態超冷極性鈉銣分子的製備以及對其碰撞性質的研究。為了把分子從弱束縛費什巴赫態轉移到基態，我們搭建了一套超穩且具備超窄線寬的激光系統。通過合適的雙光子拉曼過程，我們實現了93%的轉移效率，成功製備了密度高達6×10¹¹ cm⁻³的基態超冷鈉銣分子。通過外加靜電場，我們成功誘導基態分子達到1 Debye的等效電偶極矩，這是目前在超冷分子里實現的最大等效電偶極矩。儘管基態鈉銣分子是化學穩定的，我們依然在實驗上觀測到了分子的嚴重損耗。通過對分子內態的超精密操控，我們研究了分子在有化學反應和沒有化學反應發生情況下的損耗行為，並且觀測到了非常相似的動力學過程。此外，我們還研究了在不同偶極相互作用強度下的分子損耗，在超冷溫度下同時觀測到了s分波和d分波的貢獻。雖然這些結果還不足以確定基態分子的損耗機制，我們的成果對極性超冷氣體的研究具有重要意義。Guo, Mingyang = 基態23Na 87Rb分子的極性超冷氣體 / 郭鳴阳."December 2017."23, 87 in title are superscript.Thesis Ph.D. Chinese University of Hong Kong 2018.Includes bibliographical references (leaves 129-156).Abstracts also in Chinese.Title from PDF title page (viewed on 20, April, 2021).Guo, Mingyang = Ji tai 23Na 87Rb fen zi de ji xing chao leng qi ti / Guo Mingyang
Data from: A study on the Influence of submergence ratio on the transportation of suspended sediment in a partially vegetated channel flow
No full textRiparian or aquatic vegetation thrives with seasons. The understanding of canopies' Submergence-Ratio SR (stems' height to water depth) influence on suspended sediments' transportation is still limited. Thus, Large Eddy Simulations (LES) coupled with the Discrete Phase Method (DPM) are used to investigate the particles' 3-dimensional distribution in a partially vegetated straight channel. The spanwise distribution of particles is quantified by the Probability Density Function (PDF), showing a non-uniformity of particles in time as quantified by the PDF variance. The findings and conclusions: (Ⅰ) With SR rising, the particles' depletion effects exerted by the vegetation-side mixing layer are improved along the interface between vegetated and vegetation-side bare channel region. However, the SR has little effect on the variance of the particles' PDF in the spanwise direction when the mixing layer is fully developed. (Ⅱ) During the developing stage of the over-canopy mixing layer, submerged vegetation with higher SR gain a stronger upwards (vertical) entrainment capability. The case (SR=60%) has a higher sediment concentration than other cases in the fully developed vertical mixing layer region above canopy. (III) The vertical suspension of particles in the vegetation-side bare channel region is analysed. Particles migrating from the vegetated region are entrained into the vegetation-side bare channel region by turbulent structures. Nevertheless, the vertical concentration profile is more uniform in the vegetated region than in the vegetation-side bare channel at the same streamwise location. The cases SR=40% and 60% still have higher sediment concentrations than other cases in the vegetation-side bare channel's upper region.The corresponding author is Dr. Eldad Avital. Mingyang Wang is the first author. Funding provided by: Engineering and Physical Sciences Research CouncilCrossref Funder Registry ID: http://dx.doi.org/10.13039/501100000266Award Number:The datasets are produced mainly based on the numerical simulations, some exprimental data is collected from published literatures
An Affect-aware Socially Assistive Robot for Exercise Facilitation
No full textOlder adults generally engage in less physical activities than other age groups, which can increase the risk of developing diseases associated with aging. It is increasingly difficult for caregivers to support older adults due to the global decline in the old-age support ratio. Socially assistive robots have shown success in supporting older adults and extending the capability of healthcare workers. This thesis aims to develop: 1) an affect elicitation and detection methodology using a social robot to directly elicit user affect that occurred during human-robot interactions (HRIs) to train affect detection models; 2) an autonomous socially assistive robot to facilitate upper body exercises. Exploratory experiments with both younger and older adults were conducted to validate the robot’s ability to elicit user affect and facilitate exercises. The results showed that the robot successfully elicited and detected user affect as well as facilitated exercising, and that the participants also reported high acceptance of the robot.M.A.S.2021-11-30 00:00:0
Ferroelectric phase transitions in perovskite-type oxides and their composites studied by synchrotron radiation X-ray diffraction
No full text内容の要約博士(理学)Doctor of Philosophy in Science広島大学Hiroshima Universit
Battery charging and discharging research based on the interactive technology of smart grid and electric vehicle
No full textStudy on key technologies of optimization of big data for thermal power plant performance
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Senataxin Attenuates DNA Damage Response Activation and Suppresses Senescence
No full textOxidative stress, driven by reactive oxygen species (ROS) such as hydrogen peroxide (H2O2), induces DNA double-strand breaks (DSBs) that compromise genomic integrity. The DNA Damage Response (DDR), primarily mediated by ATM and ATR kinases, is crucial for recognizing and repairing DSBs. Senataxin (SETX), a DNA/RNA helicase, is critical in resolving R-loops, with mutations in SETX associated with neurodegenerative diseases. This study uncovers a novel function of senataxin in modulating DDR and its impact on cellular senescence. Senataxin is shown to be crucial not only for DSB repair but also for determining cell fate under oxidative stress. SETX knockout cells show impaired DSB repair and prolonged ATM/ATR signaling detected by Western blotting, leading to increased senescence, as indicated by elevated β-galactosidase activity following H2O2 exposure and I-PpoI-induced DSBs. Wild-type cells exhibit higher apoptosis levels compared to SETX knockout cells under H2O2 treatment, suggesting that senataxin promotes apoptosis over senescence in oxidative stress. This indicates that senataxin plays a protective role against the accumulation of senescent cells, potentially mitigating age-related cellular decline and neurodegenerative disease progression. These findings highlight senataxin as a critical mediator in DDR pathways and a potential therapeutic target for conditions where cellular senescence contributes to disease pathology
Harbin thermal park: transforming an abandoned thermal power plant into green infrastructure
No full textMy research goal was to explore the possibilities of post industrial sites to transform them into green infrastructure by multi-scale approach, making them not only benefit the ecology system in city scale, but also urban environment in local scale, while remaining the industrial beauty of the site
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