The research of propagation characteristics of air-to-water sound transmission is of great importance to the detection of aerial targets from underwater.In order to study the propagation characteristics of air-to-wate...The research of propagation characteristics of air-to-water sound transmission is of great importance to the detection of aerial targets from underwater.In order to study the propagation characteristics of air-to-water sound transmission in shallow water,State Key Laboratory of Acoustics,Institute of Acoustics,conducted an experiment in the South China Sea in March,2013.During the experiment,multi-frequency signals transmitted by a hooter hung on a research ship were received by an underwater hydrophone,and the distance between the hooter and the hydrophone was from 2.4 km to 9.8 km approximately.Through analyzing experimental data in this work,the experimental air-to-water transmission loss at frequencies128 Hz and 256 Hz is estimated up to 9.8 km in range,and its oscillation structure is evident.The wave-number integration approach is used to simulate theoretical air-to-water transmission losses,which are in good agreement with experimental values and to explain the experimental air-to-water sound transmission characteristics.展开更多
Pyrolysis of Shenmu coal was performed in fixed-bed reactors indirectly heated by reducing operating pressure and mounting internals in the reactor to explore their synergetic effects on coal pyrolysis. Mounting inter...Pyrolysis of Shenmu coal was performed in fixed-bed reactors indirectly heated by reducing operating pressure and mounting internals in the reactor to explore their synergetic effects on coal pyrolysis. Mounting internals particularly designed greatly improved the heat transfer inside coal bed and raised the yield of tar production.Reducing pressure further facilitated the production of tar through its suppression of secondary reactions occurring in the reactor. The absolute increase in tar yield reached 3.33 wt% in comparison with the pyrolysis in the reactor without internals under atmospheric pressure. The obtained tar yield in the reactor with internals under reduced pressure was even higher than the yield of Gray–King assay. Through experiments in a laboratory fixed bed reactor, it was also clarified that the effect of reducing pressure is related to volatile release rate in pyrolysis. It did not obviously vary tar yield at pyrolysis temperatures below 600 ℃, while the effect was evident at 650 and 700 ℃ but became limited again above 800 ℃. Under reduced pressure the produced tar contained more aliphatics and phenols but less aromatics.展开更多
Neural networks(NNs)often assign high confidence to their predictions,even for points far out of distribution,making uncertainty quantification(UQ)a challenge.When they are employed to model interatomic potentials in ...Neural networks(NNs)often assign high confidence to their predictions,even for points far out of distribution,making uncertainty quantification(UQ)a challenge.When they are employed to model interatomic potentials in materials systems,this problem leads to unphysical structures that disrupt simulations,or to biased statistics and dynamics that do not reflect the true physics.Differentiable UQ techniques can find new informative data and drive active learning loops for robust potentials.However,a variety of UQ techniques,including newly developed ones,exist for atomistic simulations and there are no clear guidelines for which are most effective or suitable for a given case.In this work,we examine multiple UQ schemes for improving the robustness of NN interatomic potentials(NNIPs)through active learning.In particular,we compare incumbent ensemble-based methods against strategies that use single,deterministic NNs:mean-variance estimation(MVE),deep evidential regression,and Gaussian mixture models(GMM).We explore three datasets ranging from in-domain interpolative learning to more extrapolative out-of-domain generalization challenges:rMD17,ammonia inversion,and bulk silica glass.Performance is measured across multiple metrics relating model error to uncertainty.Our experiments show that none of the methods consistently outperformed each other across the various metrics.Ensembling remained better at generalization and for NNIP robustness;MVE only proved effective for in-domain interpolation,while GMM was better out-of-domain;and evidential regression,despite its promise,was not the preferable alternative in any of the cases.More broadly,cost-effective,single deterministic models cannot yet consistently match or outperform ensembling for uncertainty quantification in NNIPs.展开更多
An international team of astronomers discovered delays in radio and optical fluxes from a black hole(BH)binary-about 8 and 17 days respectively-compared with the X-ray outburst from the same object.These delays,as exp...An international team of astronomers discovered delays in radio and optical fluxes from a black hole(BH)binary-about 8 and 17 days respectively-compared with the X-ray outburst from the same object.These delays,as explained by the authors,can be interpreted as evident formation of a magnetically arrested disk(MAD),a scenario predicted by a theoretical model that has long sought observational evidence for support.展开更多
The polar sea-ice plays a striking role in the interaction of sea-air in high latitudes. Recently, meteorologists investigated the influence of polar ice on the atmospheric circulation and weather in some regions. The...The polar sea-ice plays a striking role in the interaction of sea-air in high latitudes. Recently, meteorologists investigated the influence of polar ice on the atmospheric circulation and weather in some regions. The results show that the polar ice has evident local action and affects the atmospheric circulation and weather in mid-latitudes and even in the other hemisphere. However, the polar ice itself results from the variation of the展开更多
The extremely high temperatures this summer left many with lingering fear.Adequate power is the foundation for national economic and social development,and the importance of green power development is evident.
Based on the examples in modern Mongolian dialects and vernaculars,this article explores the semantic forms of clear and non-clear factual modality and compares their corresponding semantic forms of the evidential cat...Based on the examples in modern Mongolian dialects and vernaculars,this article explores the semantic forms of clear and non-clear factual modality and compares their corresponding semantic forms of the evidential category,thus putting forward the view that in the practical application of Mongolian dialects and vernaculars,factual modality and evidential modality overlap in terms of their abstract meanings and some formal conditions of expression.展开更多
Simple preparation of stimuli-responsive hydrogels with good mechanical properties and mild stimuliresponsiveness is essential for their applications as smart soft robots. Mechanically strong Janus poly（Nisopropylacr...Simple preparation of stimuli-responsive hydrogels with good mechanical properties and mild stimuliresponsiveness is essential for their applications as smart soft robots. Mechanically strong Janus poly（Nisopropylacrylamide）/graphene oxide（PNIPAM/GO） nanocomposite hydrogels with stimuli-responsive bending behaviors are prepared through a simple one-step method by using molds made of a Teflon plate and a glass plate. Residual oxygen in the air bubbles on the Teflon plate surface affects the polymerization and hence the cross-linking density, leading to the different swelling/deswelling rates of the two sides of the gels. Therefore, the hydrogels exhibit bending/unbending behaviors upon heating/cooling in water. The incorporation of GO nanosheets dramatically enhances the mechanical properties of Janus hydrogels. Meanwhile, the photo-responsive property of the GO nanosheets also imparts the hydrogels with remotecontrollable deformation under IR irradiation. The application of the Janus PNIPAM/GO hydrogels as thermo-responsive grippers is demonstrated.展开更多
Ⅰ. INTRODUCTION C. C. Me Mullen et al. determined the 11B/10B ratios of boron in samples from Searles Lake, California, and found that the absolute 11B/10B ratios were 4.046—4.072, and pointed out that the high valu...Ⅰ. INTRODUCTION C. C. Me Mullen et al. determined the 11B/10B ratios of boron in samples from Searles Lake, California, and found that the absolute 11B/10B ratios were 4.046—4.072, and pointed out that the high values given previously might be due to erroneous measurements. Schwarez et al. pointed out that the 11B/10B ratios in展开更多
The composition and structure of polymers may be tailor-made to give them various functions and specific characters. Recently, uses of functional polymers in chemical reactions have become increasingly widespread and ...The composition and structure of polymers may be tailor-made to give them various functions and specific characters. Recently, uses of functional polymers in chemical reactions have become increasingly widespread and are one of the important and rapidly developing fields of polymer science. Polymer catalysts are an important kind of functionalized polymers, and have been receiving more and more attention. The polymer catalysts consisting of polystyrene with AlCl3 and BF3 have been made by Neckers展开更多
The immediate,short-term and long-term depressor effects,the immediate effects on cardiacfunctions in grade Ⅱ and grade Ⅲ vascular hypertension,and the effects on angiotensin Ⅱ ingrade Ⅲ vascular hypertension by a...The immediate,short-term and long-term depressor effects,the immediate effects on cardiacfunctions in grade Ⅱ and grade Ⅲ vascular hypertension,and the effects on angiotensin Ⅱ ingrade Ⅲ vascular hypertension by acupuncture at otoacupoint Heart were studied in 30 cases ofvascular hypertensive patients.The immediate depressor effect of acupuncture at otoacupointStomach was also recorded for comparison.It was found that acupuncture at otoacupoint Heartproduced marked immediate depressor effect,and the short-term effective rate was 100%,thelong-term effective rate was 63.3%,as well as evident immediate effects on cardiac functionalactivities in grade Ⅱ and grade Ⅲ hypertension and marked effects on angiotensin Ⅱ in grade Ⅲhypertension.Acupuncture at otoacupoint Stomach produced no depressor effect on vascularhypertension.展开更多
We wish to report the discovery of a probable noetidiurnal growth rhythm of filamentous cyanophytes from black cherts of the e. 1400—1500 m.y. old Gaoyuzhuang Formation (Changchengian System) of Pangjiabu, Xuanhua, H...We wish to report the discovery of a probable noetidiurnal growth rhythm of filamentous cyanophytes from black cherts of the e. 1400—1500 m.y. old Gaoyuzhuang Formation (Changchengian System) of Pangjiabu, Xuanhua, Hebei Province, North China. Light microscopic obser-展开更多
Ⅰ. INTRODUCTION Let us first consider the process in which N hadrons are produced such as a+b→1+2…+m+…+N. (1) KNO-Kendall type distribution derived from the renormalization group (abbreviated as RG) equation was s...Ⅰ. INTRODUCTION Let us first consider the process in which N hadrons are produced such as a+b→1+2…+m+…+N. (1) KNO-Kendall type distribution derived from the renormalization group (abbreviated as RG) equation was supported by experiments. It is shown that the RG is appropriate for describing the properties of the quantum field of short distance in展开更多
Kvankam al mi ■ajnis ke la konsento inter la■evalo kaj mi estis definitiva, poste evidenti■is ke labesto estis pli malpardonema ol mi pensis.Postduonhora rajdado ni atingis riveron kiun oni devistransvadi. ■io est...Kvankam al mi ■ajnis ke la konsento inter la■evalo kaj mi estis definitiva, poste evidenti■is ke labesto estis pli malpardonema ol mi pensis.Postduonhora rajdado ni atingis riveron kiun oni devistransvadi. ■io estis en ordo ■is kiam ni alvenis al lamezo de la rivero, kie mi devis levi la piedojn al laalteco de la selo, por ne malsekigi la botojn. Tie la■evalo subite ekskuis sin tiel forte, ke展开更多
We shall prove the following Theorem. Let V be an n-dimensional convex compact region, g be its centre of gravity, and it a hyperplane through g. If x divides V into two parts: V1 and V2, then we
It is very important both for the general circulation modeling and for climate modeling to accurately compute the infrared cooling rates due to the atmospheric thermal, radiation. Because of the complexity of the prob...It is very important both for the general circulation modeling and for climate modeling to accurately compute the infrared cooling rates due to the atmospheric thermal, radiation. Because of the complexity of the problem, however, an exact calculation of the atmospheric infrared cooling rate is difficult. In general, some simplifications and approximations have been used in the calculation of the infrared cooling rate. One is the use of a展开更多
As COVID-19 spread around the world, it became clear that all economies would be affected by it. However, it was also evident that all economies would not be affected to the same extent. Some were better prepared for ...As COVID-19 spread around the world, it became clear that all economies would be affected by it. However, it was also evident that all economies would not be affected to the same extent. Some were better prepared for the combination of risks and challenges that the pandemic presented. One method that enabled economies to avert some of the damage that the pandemic wrought was through broad-based, active adoption of technology.展开更多
Based on the data collected from the 325-m meteorological tower and reports of precipitant radar and conventional observation, we give in this paper, a structural analysis of the characteristic of the density current ...Based on the data collected from the 325-m meteorological tower and reports of precipitant radar and conventional observation, we give in this paper, a structural analysis of the characteristic of the density current coming from thunderstorm in the lower level during the frontogenesis process of the summer sub-cold front of the Beijing region. Following the passage of the thunderstorm, the multiple gust surges ap-展开更多
基金supported by the National Natural Science Foundation of China(11434012,41561144006)Public Science and Technology Research Funds Projects of Ocean(201405032)
文摘The research of propagation characteristics of air-to-water sound transmission is of great importance to the detection of aerial targets from underwater.In order to study the propagation characteristics of air-to-water sound transmission in shallow water,State Key Laboratory of Acoustics,Institute of Acoustics,conducted an experiment in the South China Sea in March,2013.During the experiment,multi-frequency signals transmitted by a hooter hung on a research ship were received by an underwater hydrophone,and the distance between the hooter and the hydrophone was from 2.4 km to 9.8 km approximately.Through analyzing experimental data in this work,the experimental air-to-water transmission loss at frequencies128 Hz and 256 Hz is estimated up to 9.8 km in range,and its oscillation structure is evident.The wave-number integration approach is used to simulate theoretical air-to-water transmission losses,which are in good agreement with experimental values and to explain the experimental air-to-water sound transmission characteristics.
基金Supported by the National Natural Science Foundation of China(21376250)National Basic Research Program of China(2014CB744303)the Strategic Priority Research Program of Chinese Academy of Sciences(XDA07010100)
文摘Pyrolysis of Shenmu coal was performed in fixed-bed reactors indirectly heated by reducing operating pressure and mounting internals in the reactor to explore their synergetic effects on coal pyrolysis. Mounting internals particularly designed greatly improved the heat transfer inside coal bed and raised the yield of tar production.Reducing pressure further facilitated the production of tar through its suppression of secondary reactions occurring in the reactor. The absolute increase in tar yield reached 3.33 wt% in comparison with the pyrolysis in the reactor without internals under atmospheric pressure. The obtained tar yield in the reactor with internals under reduced pressure was even higher than the yield of Gray–King assay. Through experiments in a laboratory fixed bed reactor, it was also clarified that the effect of reducing pressure is related to volatile release rate in pyrolysis. It did not obviously vary tar yield at pyrolysis temperatures below 600 ℃, while the effect was evident at 650 and 700 ℃ but became limited again above 800 ℃. Under reduced pressure the produced tar contained more aliphatics and phenols but less aromatics.
文摘Neural networks(NNs)often assign high confidence to their predictions,even for points far out of distribution,making uncertainty quantification(UQ)a challenge.When they are employed to model interatomic potentials in materials systems,this problem leads to unphysical structures that disrupt simulations,or to biased statistics and dynamics that do not reflect the true physics.Differentiable UQ techniques can find new informative data and drive active learning loops for robust potentials.However,a variety of UQ techniques,including newly developed ones,exist for atomistic simulations and there are no clear guidelines for which are most effective or suitable for a given case.In this work,we examine multiple UQ schemes for improving the robustness of NN interatomic potentials(NNIPs)through active learning.In particular,we compare incumbent ensemble-based methods against strategies that use single,deterministic NNs:mean-variance estimation(MVE),deep evidential regression,and Gaussian mixture models(GMM).We explore three datasets ranging from in-domain interpolative learning to more extrapolative out-of-domain generalization challenges:rMD17,ammonia inversion,and bulk silica glass.Performance is measured across multiple metrics relating model error to uncertainty.Our experiments show that none of the methods consistently outperformed each other across the various metrics.Ensembling remained better at generalization and for NNIP robustness;MVE only proved effective for in-domain interpolation,while GMM was better out-of-domain;and evidential regression,despite its promise,was not the preferable alternative in any of the cases.More broadly,cost-effective,single deterministic models cannot yet consistently match or outperform ensembling for uncertainty quantification in NNIPs.
文摘An international team of astronomers discovered delays in radio and optical fluxes from a black hole(BH)binary-about 8 and 17 days respectively-compared with the X-ray outburst from the same object.These delays,as explained by the authors,can be interpreted as evident formation of a magnetically arrested disk(MAD),a scenario predicted by a theoretical model that has long sought observational evidence for support.
文摘The polar sea-ice plays a striking role in the interaction of sea-air in high latitudes. Recently, meteorologists investigated the influence of polar ice on the atmospheric circulation and weather in some regions. The results show that the polar ice has evident local action and affects the atmospheric circulation and weather in mid-latitudes and even in the other hemisphere. However, the polar ice itself results from the variation of the
文摘The extremely high temperatures this summer left many with lingering fear.Adequate power is the foundation for national economic and social development,and the importance of green power development is evident.
文摘Based on the examples in modern Mongolian dialects and vernaculars,this article explores the semantic forms of clear and non-clear factual modality and compares their corresponding semantic forms of the evidential category,thus putting forward the view that in the practical application of Mongolian dialects and vernaculars,factual modality and evidential modality overlap in terms of their abstract meanings and some formal conditions of expression.
基金financially supported by the National Natural Science Foundation of China(No.21274013)
文摘Simple preparation of stimuli-responsive hydrogels with good mechanical properties and mild stimuliresponsiveness is essential for their applications as smart soft robots. Mechanically strong Janus poly（Nisopropylacrylamide）/graphene oxide（PNIPAM/GO） nanocomposite hydrogels with stimuli-responsive bending behaviors are prepared through a simple one-step method by using molds made of a Teflon plate and a glass plate. Residual oxygen in the air bubbles on the Teflon plate surface affects the polymerization and hence the cross-linking density, leading to the different swelling/deswelling rates of the two sides of the gels. Therefore, the hydrogels exhibit bending/unbending behaviors upon heating/cooling in water. The incorporation of GO nanosheets dramatically enhances the mechanical properties of Janus hydrogels. Meanwhile, the photo-responsive property of the GO nanosheets also imparts the hydrogels with remotecontrollable deformation under IR irradiation. The application of the Janus PNIPAM/GO hydrogels as thermo-responsive grippers is demonstrated.
文摘Ⅰ. INTRODUCTION C. C. Me Mullen et al. determined the 11B/10B ratios of boron in samples from Searles Lake, California, and found that the absolute 11B/10B ratios were 4.046—4.072, and pointed out that the high values given previously might be due to erroneous measurements. Schwarez et al. pointed out that the 11B/10B ratios in
文摘The composition and structure of polymers may be tailor-made to give them various functions and specific characters. Recently, uses of functional polymers in chemical reactions have become increasingly widespread and are one of the important and rapidly developing fields of polymer science. Polymer catalysts are an important kind of functionalized polymers, and have been receiving more and more attention. The polymer catalysts consisting of polystyrene with AlCl3 and BF3 have been made by Neckers
文摘The immediate,short-term and long-term depressor effects,the immediate effects on cardiacfunctions in grade Ⅱ and grade Ⅲ vascular hypertension,and the effects on angiotensin Ⅱ ingrade Ⅲ vascular hypertension by acupuncture at otoacupoint Heart were studied in 30 cases ofvascular hypertensive patients.The immediate depressor effect of acupuncture at otoacupointStomach was also recorded for comparison.It was found that acupuncture at otoacupoint Heartproduced marked immediate depressor effect,and the short-term effective rate was 100%,thelong-term effective rate was 63.3%,as well as evident immediate effects on cardiac functionalactivities in grade Ⅱ and grade Ⅲ hypertension and marked effects on angiotensin Ⅱ in grade Ⅲhypertension.Acupuncture at otoacupoint Stomach produced no depressor effect on vascularhypertension.
文摘We wish to report the discovery of a probable noetidiurnal growth rhythm of filamentous cyanophytes from black cherts of the e. 1400—1500 m.y. old Gaoyuzhuang Formation (Changchengian System) of Pangjiabu, Xuanhua, Hebei Province, North China. Light microscopic obser-
文摘Ⅰ. INTRODUCTION Let us first consider the process in which N hadrons are produced such as a+b→1+2…+m+…+N. (1) KNO-Kendall type distribution derived from the renormalization group (abbreviated as RG) equation was supported by experiments. It is shown that the RG is appropriate for describing the properties of the quantum field of short distance in
文摘Kvankam al mi ■ajnis ke la konsento inter la■evalo kaj mi estis definitiva, poste evidenti■is ke labesto estis pli malpardonema ol mi pensis.Postduonhora rajdado ni atingis riveron kiun oni devistransvadi. ■io estis en ordo ■is kiam ni alvenis al lamezo de la rivero, kie mi devis levi la piedojn al laalteco de la selo, por ne malsekigi la botojn. Tie la■evalo subite ekskuis sin tiel forte, ke
文摘We shall prove the following Theorem. Let V be an n-dimensional convex compact region, g be its centre of gravity, and it a hyperplane through g. If x divides V into two parts: V1 and V2, then we
文摘It is very important both for the general circulation modeling and for climate modeling to accurately compute the infrared cooling rates due to the atmospheric thermal, radiation. Because of the complexity of the problem, however, an exact calculation of the atmospheric infrared cooling rate is difficult. In general, some simplifications and approximations have been used in the calculation of the infrared cooling rate. One is the use of a
文摘As COVID-19 spread around the world, it became clear that all economies would be affected by it. However, it was also evident that all economies would not be affected to the same extent. Some were better prepared for the combination of risks and challenges that the pandemic presented. One method that enabled economies to avert some of the damage that the pandemic wrought was through broad-based, active adoption of technology.
文摘Based on the data collected from the 325-m meteorological tower and reports of precipitant radar and conventional observation, we give in this paper, a structural analysis of the characteristic of the density current coming from thunderstorm in the lower level during the frontogenesis process of the summer sub-cold front of the Beijing region. Following the passage of the thunderstorm, the multiple gust surges ap-
