40 research outputs found
Effects of Dynamic Properties of Rockfill Materials on Seismic Response of Concrete-Faced Rockfill Dams
In this paper, the equivalent-linear method is used for three-dimensional seismic response analyses of concrete-faced rockfill dams (CFRDs). Different combinations of various parameters such as small-strain shear modulus, strain-dependent patterns of modulus and hysteretic damping, are considered to systematically investigate the effects of dynamic properties of rockfill-type coarse-grained materials on seismic dynamic response of CFRDs. It is concluded that the nonlinearity of embankment material has a significant effect on both vibration characteristics and seismic response behavior of CFRDs. Numerical results presented are instructive to gain a better understanding on earthquake-resistant behavior of CFRDs and the effects of dynamic properties of rockfills
On the Generation of Medical Question-Answer Pairs
Question answering (QA) has achieved promising progress recently. However,
answering a question in real-world scenarios like the medical domain is still
challenging, due to the requirement of external knowledge and the insufficient
quantity of high-quality training data. In the light of these challenges, we
study the task of generating medical QA pairs in this paper. With the insight
that each medical question can be considered as a sample from the latent
distribution of questions given answers, we propose an automated medical QA
pair generation framework, consisting of an unsupervised key phrase detector
that explores unstructured material for validity, and a generator that involves
a multi-pass decoder to integrate structural knowledge for diversity. A series
of experiments have been conducted on a real-world dataset collected from the
National Medical Licensing Examination of China. Both automatic evaluation and
human annotation demonstrate the effectiveness of the proposed method. Further
investigation shows that, by incorporating the generated QA pairs for training,
significant improvement in terms of accuracy can be achieved for the
examination QA system.Comment: AAAI 202
Graphical analysis-based calculation method of concrete strength
This study established a three-dimensional random spherical aggregate model of concrete. Models with various volume contents of coarse aggregate were sliced, and slice areas were statistically analyzed. To study the effects of the coarse aggregate volume content and the interfacial transition zone (ITZ) strength on concreteâs compressive strength, a concrete strength calculation method based on graphical analysis was proposed. The ratio of crown area B to sectional area A of the spherical aggregate model was found to be close to 1.5. At the ITZ strength below 70% of the mortar strength, the increased volume content of coarse aggregate reduced the compressive strength of concrete, with the opposite trend observed at the ITZ strength exceeding 70% of the mortar strength
Controlling Nucleation and Fabricating Nanoparticulate Formulation of Sorafenib Using a High-Gravity Rotating Packed Bed
Nucleation
is the initial step of the crystallization process and
is the significant step to prepare nanometer-sized crystalline materials.
In this work, we systematically investigated the nucleation kinetics
of poorly water-soluble drug sorafenib when precipitated by liquid
antisolvent precipitation in high-gravity rotating packed bed. We
found that high-gravity field tremendously promoted the nucleation
rate, and the nucleation rate was increased by 2â3 orders of
magnitude over that in the stirred tank reactor. Moreover, polymer
excipients have a significant impact on nucleation; especially, polyÂ(vinylpyrrolidone)
(PVP) could increase the nucleation rate by 3 orders of magnitude
over that without excipient. Finally, stable amorphous sorafenib nanoparticulate
formulation with a particle size of 80 nm was obtained by controlling
nucleation in RPB. Compared to the coarse drug, the nanoparticulate
formulation performed faster drug release and had much better cytotoxicity.
In vivo pharmacokinetics of the nanoparticulate formulation displayed
the increase in plasma concentration time curve (AUC<sub>0ââ</sub>) and maximum plasma concentration (<i>C</i><sub>max</sub>), which demonstrated nanoparticulate formulation could enhance the
bioavailability and exhibit extensive potential in the pharmaceutical
industry
Effects of exogenous application of salicylic acid on drought performance of medicinal plant, Fritillaria przewalskii Maxim
This study investigated the effects of salicylic acid (SA) foliar application on Fritillariaprzewalskii under drought stress condition. Plants were subjected to three irrigation regimes, 75-80% control (CK), 60-65% medium stress (M) and 40-45% severe stress (S) of the field capacity and three levels of SA, 0.0, 0.5 and 1.0 mM. Relative water content (RWC), proline content, total soluble carbohydrates, chlorophyll âaâ (Chl a), chlorophyll âbâ (Chl b), chlorophyll âa + bâ (Chl a + b), carotenoids contents, malondialdehyde (MDA) contents and activities of several antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), glutathione reductase (GR) and ascorbate peroxidase (APX) activity were measured. RWC, soluble carbohydrates, Chl b, Chl a + b, MDA content and activities of antioxidant enzymes (SOD, POD, CAT, GR and APX) were significantly affected by water deprivation without SA. Exogenous SA significantly increased the content of RWC, total leaf soluble carbohydrates, leaf proline and Chl b at moderate water deficit and severe water deficit. MDA content was decreased significantly by exogenous SA. The activities of antioxidant enzymes (SOD, POD, CAT, GR and APX) were also significantly affected by exogenous SA. However, the content of Chl a, Chl a + b, and carotenoids were not significantly affected by exogenous SA.Cette Ă©tude a examinĂ© les effets de lâapplication foliaire dâacide salicylique (AS) sur Fritillariaprzewalskii en condition de sĂ©cheresse. Les plantes ont Ă©tĂ© soumises Ă trois rĂ©gimes dâirrigation : 75-80 % comme contrĂŽle (CK), 60-65 % de stress moyen (M) et 40-45 % de stress sĂ©vĂšre (S) de la capacitĂ© au champ et trois niveaux dâAS : 0,0, 0,5 et 1,0 mM. Les teneurs en eau relative (RWC), en proline, glucides solubles totaux, chlorophylle « a » (Chl a), chlorophylle « b » (Chl b), chlorophylle « a + b » (Chl a + b), teneurs en carotĂ©noĂŻdes et malondialdĂ©hyde (MDA) ont Ă©tĂ© mesurĂ©es, ainsi que les activitĂ©s de plusieurs enzymes antioxydantes telles que la superoxyde dismutase (SOD), la peroxydase (POD), la catalase (CAT), la glutathion rĂ©ductase (GR) et lâascorbate peroxydase (APX). La RWC, les glucides solubles, Chl  b, Chl a + b, la teneur en MDA et les activitĂ©s des enzymes antioxydantes (SOD, POD, CAT, GR et APX) Ă©taient significativement affectĂ©es par la privation en eau sans AS. LâAS exogĂšne a considĂ©rablement augmentĂ© la teneur en RWC, en glucides solubles dans les feuilles, en proline et en Chl b en dĂ©ficit hydrique modĂ©rĂ© et sĂ©vĂšre. Le contenu en MDA a Ă©tĂ© rĂ©duit de maniĂšre significative par lâAS exogĂšne. Les activitĂ©s des enzymes antioxydantes (SOD, POD, CAT, GR et APX) Ă©taient Ă©galement significativement affectĂ©es par les AS exogĂšnes. Cependant, les teneurs en Chl a, Chl a + b et les carotĂ©noĂŻdes nâĂ©taient pas significativement affectĂ©es par les AS exogĂšnes
A Practical Superconducting DC Dynamo for Charging Conduction-Cooled HTS Magnet
At present, HTS magnets cannot operate in the real closed-loop persistent current mode due to the existence of joint resistance, flux creep, and AC loss of the HTS tape. Instead of using a current source, HTS flux pumps are capable of injecting flux into closed HTS magnets without electrical contact. This paper presents a practical superconducting DC dynamo for charging a conduction-cooled HTS magnet system based on a flux-pumping technique. To minimize heat losses, the rotor is driven by a servo motor mounted outside the vacuum dewar by utilizing magnetic fluid dynamic sealing. Different parameters, such as air gap and rotating speed, have been tested to investigate the best pumping effect, and finally, it successfully powers a 27.3 mH HTS non-insulated double-pancake coil to the current of 54.2 A within 76 min. As a low-cost and compact substitute for the traditional current source, the realization of a contactless DC power supply can significantly improve the flexibility and mobility of the HTS magnet system and could be of great significance for the technological innovation of future HTS magnets used in offshore wind turbines, biomedical, aerospace, etc
Effets de lâapplication exogĂšne dâacide salicylique sur la rĂ©sistance Ă la sĂ©cheresse dâune plante mĂ©dicinale, Fritillaria przewalskii Maxim
This study investigated the effects of salicylic acid (SA) foliar application on Fritillariaprzewalskii under drought stress condition. Plants were subjected to three irrigation regimes, 75-80% control (CK), 60-65% medium stress (M) and 40-45% severe stress (S) of the field capacity and three levels of SA, 0.0, 0.5 and 1.0 mM. Relative water content (RWC), proline content, total soluble carbohydrates, chlorophyll âaâ (Chl a), chlorophyll âbâ (Chl b), chlorophyll âa + bâ (Chl a + b), carotenoids contents, malondialdehyde (MDA) contents and activities of several antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), glutathione reductase (GR) and ascorbate peroxidase (APX) activity were measured. RWC, soluble carbohydrates, Chl b, Chl a + b, MDA content and activities of antioxidant enzymes (SOD, POD, CAT, GR and APX) were significantly affected by water deprivation without SA. Exogenous SA significantly increased the content of RWC, total leaf soluble carbohydrates, leaf proline and Chl b at moderate water deficit and severe water deficit. MDA content was decreased significantly by exogenous SA. The activities of antioxidant enzymes (SOD, POD, CAT, GR and APX) were also significantly affected by exogenous SA. However, the content of Chl a, Chl a + b, and carotenoids were not significantly affected by exogenous SA.Cette Ă©tude a examinĂ© les effets de lâapplication foliaire dâacide salicylique (AS) sur Fritillariaprzewalskii en condition de sĂ©cheresse. Les plantes ont Ă©tĂ© soumises Ă trois rĂ©gimes dâirrigation : 75-80 % comme contrĂŽle (CK), 60-65 % de stress moyen (M) et 40-45 % de stress sĂ©vĂšre (S) de la capacitĂ© au champ et trois niveaux dâAS : 0,0, 0,5 et 1,0 mM. Les teneurs en eau relative (RWC), en proline, glucides solubles totaux, chlorophylle « a » (Chl a), chlorophylle « b » (Chl b), chlorophylle « a + b » (Chl a + b), teneurs en carotĂ©noĂŻdes et malondialdĂ©hyde (MDA) ont Ă©tĂ© mesurĂ©es, ainsi que les activitĂ©s de plusieurs enzymes antioxydantes telles que la superoxyde dismutase (SOD), la peroxydase (POD), la catalase (CAT), la glutathion rĂ©ductase (GR) et lâascorbate peroxydase (APX). La RWC, les glucides solubles, Chl  b, Chl a + b, la teneur en MDA et les activitĂ©s des enzymes antioxydantes (SOD, POD, CAT, GR et APX) Ă©taient significativement affectĂ©es par la privation en eau sans AS. LâAS exogĂšne a considĂ©rablement augmentĂ© la teneur en RWC, en glucides solubles dans les feuilles, en proline et en Chl b en dĂ©ficit hydrique modĂ©rĂ© et sĂ©vĂšre. Le contenu en MDA a Ă©tĂ© rĂ©duit de maniĂšre significative par lâAS exogĂšne. Les activitĂ©s des enzymes antioxydantes (SOD, POD, CAT, GR et APX) Ă©taient Ă©galement significativement affectĂ©es par les AS exogĂšnes. Cependant, les teneurs en Chl a, Chl a + b et les carotĂ©noĂŻdes nâĂ©taient pas significativement affectĂ©es par les AS exogĂšnes