We propose a design of tunable double-band perfect absorbers based on the resonance absorption in acoustic metasurfaces with nesting helical tracks and deep-subwavelength thicknesses(<λ/30 withλbeing the operatio...We propose a design of tunable double-band perfect absorbers based on the resonance absorption in acoustic metasurfaces with nesting helical tracks and deep-subwavelength thicknesses(<λ/30 withλbeing the operation wavelength).By rotating the cover cap with an open aperture on the nesting helical tracks,we can tailor the effective lengths of resonant tubular cavities in the absorber at will,while the absorption peak frequency is flexibly shifted in spectrum and the acoustic impedance is roughly matched with air.The simulated particle velocity fields at different configurations reveal that sound absorption mainly occurs at the open aperture.Our experiment measurements agree well with the theoretical analysis and simulation,demonstrating the wide-spectrum and tunable absorption performance of the designed flat acoustic device.展开更多
In quantum mechanics,a norm-squared wave function can be interpreted as the probability density that describes the likelihood of a particle to be measured in a given position or momentum.This statistical property is a...In quantum mechanics,a norm-squared wave function can be interpreted as the probability density that describes the likelihood of a particle to be measured in a given position or momentum.This statistical property is at the core of the fuzzy structure of microcosmos.Recently,hybrid neural structures raised intense attention,resulting in various intelligent systems with farreaching influence.Here,we propose a probability-density-based deep learning paradigm for the fuzzy design of functional metastructures.In contrast to other inverse design methods,our probability-density-based neural network can efficiently evaluate and accurately capture all plausible metastructures in a high-dimensional parameter space.Local maxima in probability density distribution correspond to the most likely candidates to meet the desired performances.We verify this universally adaptive approach in but not limited to acoustics by designing multiple metastructures for each targeted transmission spectrum,with experiments unequivocally demonstrating the effectiveness and generalization of the inverse design.展开更多
To the Editor： Here we report a craniotomy under general anesthesia successfully performed at a 4350-m altitude and the patient＇s follow-up results. To the best of our knowledge, this is one craniotomy carried out a...To the Editor： Here we report a craniotomy under general anesthesia successfully performed at a 4350-m altitude and the patient＇s follow-up results. To the best of our knowledge, this is one craniotomy carried out at the highest altitude in the world to date.A 21-year-old man occurred spontaneous light headache in the Ali area at a 4350-m altitude in the Tibet autonomous region of China on October 23,2011, and his headache became severe gradually. Three days later, the patient was in a coma with 5 scores （E1V1M3） on the Glasgow Coma Scale （GCS）; his left pupil diameter was 5.0 mm and right pupil diameter was 3.0 ram, both direct and indirect light reflex of the bilateral pupils disappeared. Craniocerebral computed tomography （CT） scan indicated a large acute subdural hematoma located in the left fronto-temporo-parietal region, widespread subarachnoid hemorrhage and brain herniation [Figure l a-c]. Emergency treatment was given for the patient in time, including continuous mask oxygen inhalation, strong dehydration （20% mannitol 250 ml ＋ furosemide 10 mg ＋ dexamethasone 5 rag, fast intravenous drip, once per 5 h）, and medical hemostasis.展开更多
基金National Natural Science Foundation of China(Grant Nos.1167434611704284+2 种基金11690030and 11690032)Bird Nest Plan of HUST。
文摘We propose a design of tunable double-band perfect absorbers based on the resonance absorption in acoustic metasurfaces with nesting helical tracks and deep-subwavelength thicknesses(<λ/30 withλbeing the operation wavelength).By rotating the cover cap with an open aperture on the nesting helical tracks,we can tailor the effective lengths of resonant tubular cavities in the absorber at will,while the absorption peak frequency is flexibly shifted in spectrum and the acoustic impedance is roughly matched with air.The simulated particle velocity fields at different configurations reveal that sound absorption mainly occurs at the open aperture.Our experiment measurements agree well with the theoretical analysis and simulation,demonstrating the wide-spectrum and tunable absorption performance of the designed flat acoustic device.
基金This work is financially supported by the National Natural Science Foundation of China(Grant Nos.11674119,11704284,11774297,11690030,and 11690032)J.Z.acknowledges the financial support from the General Research Fund of Hong Kong Research Grants Council(Grant No.15205219)Y.G.P.and A.A.acknowledge the support of the National Science Foundation and the Simons Foundation.X.-F.Z.acknowledges the Bird Nest Plan of HUST.
文摘In quantum mechanics,a norm-squared wave function can be interpreted as the probability density that describes the likelihood of a particle to be measured in a given position or momentum.This statistical property is at the core of the fuzzy structure of microcosmos.Recently,hybrid neural structures raised intense attention,resulting in various intelligent systems with farreaching influence.Here,we propose a probability-density-based deep learning paradigm for the fuzzy design of functional metastructures.In contrast to other inverse design methods,our probability-density-based neural network can efficiently evaluate and accurately capture all plausible metastructures in a high-dimensional parameter space.Local maxima in probability density distribution correspond to the most likely candidates to meet the desired performances.We verify this universally adaptive approach in but not limited to acoustics by designing multiple metastructures for each targeted transmission spectrum,with experiments unequivocally demonstrating the effectiveness and generalization of the inverse design.
基金supported by the National Natural Science Foundation of China (11674119, 11774297, 11690030, 11690032)the support from the General Research Fund (GRF) scheme of Research Grants Council of Hong Kong (Poly U 152119/18E)。
基金This study was supported by a grant from the National Natural Science Foundation of China
文摘To the Editor： Here we report a craniotomy under general anesthesia successfully performed at a 4350-m altitude and the patient＇s follow-up results. To the best of our knowledge, this is one craniotomy carried out at the highest altitude in the world to date.A 21-year-old man occurred spontaneous light headache in the Ali area at a 4350-m altitude in the Tibet autonomous region of China on October 23,2011, and his headache became severe gradually. Three days later, the patient was in a coma with 5 scores （E1V1M3） on the Glasgow Coma Scale （GCS）; his left pupil diameter was 5.0 mm and right pupil diameter was 3.0 ram, both direct and indirect light reflex of the bilateral pupils disappeared. Craniocerebral computed tomography （CT） scan indicated a large acute subdural hematoma located in the left fronto-temporo-parietal region, widespread subarachnoid hemorrhage and brain herniation [Figure l a-c]. Emergency treatment was given for the patient in time, including continuous mask oxygen inhalation, strong dehydration （20% mannitol 250 ml ＋ furosemide 10 mg ＋ dexamethasone 5 rag, fast intravenous drip, once per 5 h）, and medical hemostasis.
