All-inorganic CsPbI_(3) perovskite has attracted wide attention due to its desirable optical bandgap(Eg:∼1.7 eV)as well as high chemical stability.Nevertheless,the photovoltaic performance of CsPbI_(3) perovskite sol...All-inorganic CsPbI_(3) perovskite has attracted wide attention due to its desirable optical bandgap(Eg:∼1.7 eV)as well as high chemical stability.Nevertheless,the photovoltaic performance of CsPbI_(3) perovskite solar cells(PSCs)was limited by severe nonradiative charge recombination due to high defect density at the grain boundary and surface of perovskitefilms.To address this issue,a pyrrolidinium iodide(PyI)molecule was introduced to modify the surface and grain boundary of CsPbI_(3) perovskitefilms to passivate defects,which improves the quality of CsPbI_(3) perovskitefilms as well as induces the generation of a quasi-2D Py_(2)CsPb_(2)I_(7) capping layer between per-ovskite layer and hole transport layer.Such quasi-2D Py_(2)CsPb_(2)I_(7) capping layer optimizes interface contact between CsPbI_(3) perovskite layer and hole transport layer and blocks the electron transfer from CsPbI_(3) perovskite photoactive layer to the hole transport layer.As a result,the performance of CsPbI_(3) PSCs is well improved to 17.87%for power conversion efficiency(PCE)with an ultra-high fill factor(FF)of 0.84.In addition,the PyI mole-cule modified CsPbI_(3) perovskite devices exhibit excellent stability,which remains its initial PCE almost unchanged after aging for 35 days under the dry air atmosphere(temperature:20℃–30℃,control relative humid-ity(RH):<10%).展开更多
In recent years, a growing number of math contents are available on the Web. When conventional search engines deal with mathematical expressions, the two-dimen- sion-al structure of mathematical expressions is lost, w...In recent years, a growing number of math contents are available on the Web. When conventional search engines deal with mathematical expressions, the two-dimen- sion-al structure of mathematical expressions is lost, which results in a low performance of math retrieval. While the retrieval technology specifically designed for mathematical expressions is not mature currently. Aiming at these problems, an improved mathematical expression indexing and matching method was proposed through employing full text index method to deal with the two-dimensional structure of mathematical expressions. Firstly, through the fully consideration of LaTeX formulae’ characteristics, a feature representation method of mathematical expressions and a clustering method of feature keywords were put forward. Then, an improved inter-relevant successive trees index model was applied to the construction of the mathematical expression index, in which the cluster algorithm of mathematical expression features was employed to solve the problem of the quantity growth of the trees in processing large amount of formulae. Finally, the matching algorithms of mathematical expressions were given which provide four query modes called exact matching, compatible matching, sub-expression matching and fuzzy matching. In browser/server mode, 110027 formulae were used as experimental samples. The index file size was 29.02 Mb. The average time of retrieval was 1.092 seconds. The experimental result shows the effectiveness of the method.展开更多
Defects formed at the surface,buried interface and grain boundaries(GB)of CsPbI_(3)perovskite films considerably limit photovoltaic performance.Such defects could be passivated effectively by the most prevalent post m...Defects formed at the surface,buried interface and grain boundaries(GB)of CsPbI_(3)perovskite films considerably limit photovoltaic performance.Such defects could be passivated effectively by the most prevalent post modification strategy without compromising the photoelectric properties of perovskite films,but it is still a great challenge to make this strategy comprehensive to different defects spatially distributed throughout the films.Herein,a spatially selective defect management(SSDM)strategy is developed to roundly passivate various defects at different locations within the perovskite film by a facile one-step treatment procedure using a piperazine-1,4-diium tetrafluoroborate(PZD(BF_(4))_(2))solution.The small-size PZD^(2+)cations could penetrate into the film interior and even make it all the way to the buried interface of CsPbI_(3)perovskite films,while the BF_(4)^(-)anions,with largely different properties from I^(-)anions,mainly anchor on the film surface.Consequently,virtually all the defects at the surface,buried interface and grain boundaries of CsPbI_(3)perovskite films are effectively healed,leading to significantly improved film quality,enhanced phase stability,optimized energy level alignment and promoted carrier transport.With these films,the fabricated CsPbI_(3)PSCs based on carbon electrode(C-PSCs)achieve an efficiency of18.27%,which is among the highest-reported values for inorganic C-PSCs,and stability of 500 h at 85℃with 65%efficiency maintenance.展开更多
Throat cancer treatment involves surgical removal of the tumor,leaving patients with facial disfigurement as well as temporary or permanent loss of voice.Surface electromyography(sEMG)generated from the jaw contains l...Throat cancer treatment involves surgical removal of the tumor,leaving patients with facial disfigurement as well as temporary or permanent loss of voice.Surface electromyography(sEMG)generated from the jaw contains lots of voice information.However,it is difficult to record because of not only the weakness of the signals but also the steep skin curvature.This paper demonstrates the design of an imperceptible,flexible epidermal sEMG tattoo-like patch with the thickness of less than 10μm and peeling strength of larger than 1N cm−1 that exhibits large adhesiveness to complex biological surfaces and is thus capable of sEMG recording for silent speech recognition.When a tester speaks silently,the patch shows excellent performance in recording the sEMG signals from three muscle channels and recognizing those frequently used instructions with high accuracy by using the wavelet decomposition and pattern recognization.The average accuracy of action instructions can reach up to 89.04%,and the average accuracy of emotion instructions is as high as 92.33%.To demonstrate the functionality of tattoo-like patches as a new human–machine interface(HMI)for patients with loss of voice,the intelligent silent speech recognition,voice synthesis,and virtual interaction have been implemented,which are of great importance in helping these patients communicate with people and make life more enjoyable.展开更多
Pulse diagnosis is an irreplaceable part of traditional Chinese medical science.However,application of the traditional pulse monitoring method was restricted in the modernization of Chinese medical science since it wa...Pulse diagnosis is an irreplaceable part of traditional Chinese medical science.However,application of the traditional pulse monitoring method was restricted in the modernization of Chinese medical science since it was difficult to capture real signals and integrate obscure feelings with a modern data platform.Herein,a novel multichannel pulse monitoring platform based on traditional Chinese medical science pulse theory and wearable electronics was proposed.The pulse sensing platform simultaneously detected pulse conditions at three pulse positions(Chi,Cun,and Guan).These signals were fitted to smooth surfaces to enable 3-dimensional pulse mapping,which vividly revealed the shape of the pulse length and width and compensated for the shortcomings of traditional single-point pulse sensors.Moreover,the pulse sensing system could measure the pulse signals from different individuals with different conditions and distinguish the differences in pulse signals.In addition,this system could provide full information on the temporal and spatial dimensions of a person’s pulse waveform,which is similar to the true feelings of doctors’fingertips.This innovative,cost-effective,easily designed pulse monitoring platform based on flexible pressure sensor arrays may provide novel applications in modernization of Chinese medical science or intelligent health care.展开更多
Aging is accompanied by the decline of organismal functions and a series of prominent hallmarks,including genetic and epigenetic alterations.These aging-associated epigenetic changes include DNA methylation,histone mo...Aging is accompanied by the decline of organismal functions and a series of prominent hallmarks,including genetic and epigenetic alterations.These aging-associated epigenetic changes include DNA methylation,histone modification,chromatin remodeling,non-coding RNA(ncRNA)regulation,and RNA modification,all of which participate in the regulation of the aging process,and hence contribute to aging-related diseases.Therefore,understanding the epigenetic mechanisms in aging will provide new avenues to develop strategies to delay aging.Indeed,aging interventions based on manipulating epigenetic mechanisms have led to the alleviation of aging or the extension of the lifespan in animal models.Small molecule-based therapies and reprogramming strategies that enable epigenetic rejuvenation have been developed for ameliorating or reversing aging-related conditions.In addition,adopting health-promoting activities,such as caloric restriction,exercise,and calibrating circadian rhythm,has been demonstrated to delay aging.Furthermore,various clinical trials for aging intervention are ongoing,providing more evidence of the safety and efficacy of these therapies.Here,we review recent work on the epigenetic regulation of aging and outline the advances in intervention strategies for aging and age-associated diseases.A better understanding of the critical roles of epigenetics in the aging process will lead to more clinical advances in the prevention of human aging and therapy of aging-related diseases.展开更多
The internal availability of silent speech serves as a translator for people with aphasia and keeps human–machine/human interactions working under various disturbances.This paper develops a silent speech strategy to ...The internal availability of silent speech serves as a translator for people with aphasia and keeps human–machine/human interactions working under various disturbances.This paper develops a silent speech strategy to achieve all-weather,natural interactions.The strategy requires few usage specialized skills like sign language but accurately transfers high-capacity information in complicated and changeable daily environments.In the strategy,the tattoo-like electronics imperceptibly attached on facial skin record high-quality bio-data of various silent speech,and the machine-learning algorithm deployed on the cloud recognizes accurately the silent speech and reduces the weight of the wireless acquisition module.A series of experiments show that the silent speech recognition system(SSRS)can enduringly comply with large deformation(~45%)of faces by virtue of the electricitypreferred tattoo-like electrodes and recognize up to 110 words covering daily vocabularies with a high average accuracy of 92.64%simply by use of small-sample machine learning.We successfully apply the SSRS to 1-day routine life,including daily greeting,running,dining,manipulating industrial robots in deafening noise,and expressing in darkness,which shows great promotion in real-world applications.展开更多
基金National Natural Science Foundation of China,Grant No.21875013,H.N.ChenBeijing Natural Science Foundation,Grant No.2182031,H.N.Chen.
文摘All-inorganic CsPbI_(3) perovskite has attracted wide attention due to its desirable optical bandgap(Eg:∼1.7 eV)as well as high chemical stability.Nevertheless,the photovoltaic performance of CsPbI_(3) perovskite solar cells(PSCs)was limited by severe nonradiative charge recombination due to high defect density at the grain boundary and surface of perovskitefilms.To address this issue,a pyrrolidinium iodide(PyI)molecule was introduced to modify the surface and grain boundary of CsPbI_(3) perovskitefilms to passivate defects,which improves the quality of CsPbI_(3) perovskitefilms as well as induces the generation of a quasi-2D Py_(2)CsPb_(2)I_(7) capping layer between per-ovskite layer and hole transport layer.Such quasi-2D Py_(2)CsPb_(2)I_(7) capping layer optimizes interface contact between CsPbI_(3) perovskite layer and hole transport layer and blocks the electron transfer from CsPbI_(3) perovskite photoactive layer to the hole transport layer.As a result,the performance of CsPbI_(3) PSCs is well improved to 17.87%for power conversion efficiency(PCE)with an ultra-high fill factor(FF)of 0.84.In addition,the PyI mole-cule modified CsPbI_(3) perovskite devices exhibit excellent stability,which remains its initial PCE almost unchanged after aging for 35 days under the dry air atmosphere(temperature:20℃–30℃,control relative humid-ity(RH):<10%).
文摘In recent years, a growing number of math contents are available on the Web. When conventional search engines deal with mathematical expressions, the two-dimen- sion-al structure of mathematical expressions is lost, which results in a low performance of math retrieval. While the retrieval technology specifically designed for mathematical expressions is not mature currently. Aiming at these problems, an improved mathematical expression indexing and matching method was proposed through employing full text index method to deal with the two-dimensional structure of mathematical expressions. Firstly, through the fully consideration of LaTeX formulae’ characteristics, a feature representation method of mathematical expressions and a clustering method of feature keywords were put forward. Then, an improved inter-relevant successive trees index model was applied to the construction of the mathematical expression index, in which the cluster algorithm of mathematical expression features was employed to solve the problem of the quantity growth of the trees in processing large amount of formulae. Finally, the matching algorithms of mathematical expressions were given which provide four query modes called exact matching, compatible matching, sub-expression matching and fuzzy matching. In browser/server mode, 110027 formulae were used as experimental samples. The index file size was 29.02 Mb. The average time of retrieval was 1.092 seconds. The experimental result shows the effectiveness of the method.
基金supported by the National Natural Science Foundation of China(21875013,U2001217)the Beijing Natural Science Foundation(2182031)Shenzhen Basic Research(JCYJ20220818101018038)。
文摘Defects formed at the surface,buried interface and grain boundaries(GB)of CsPbI_(3)perovskite films considerably limit photovoltaic performance.Such defects could be passivated effectively by the most prevalent post modification strategy without compromising the photoelectric properties of perovskite films,but it is still a great challenge to make this strategy comprehensive to different defects spatially distributed throughout the films.Herein,a spatially selective defect management(SSDM)strategy is developed to roundly passivate various defects at different locations within the perovskite film by a facile one-step treatment procedure using a piperazine-1,4-diium tetrafluoroborate(PZD(BF_(4))_(2))solution.The small-size PZD^(2+)cations could penetrate into the film interior and even make it all the way to the buried interface of CsPbI_(3)perovskite films,while the BF_(4)^(-)anions,with largely different properties from I^(-)anions,mainly anchor on the film surface.Consequently,virtually all the defects at the surface,buried interface and grain boundaries of CsPbI_(3)perovskite films are effectively healed,leading to significantly improved film quality,enhanced phase stability,optimized energy level alignment and promoted carrier transport.With these films,the fabricated CsPbI_(3)PSCs based on carbon electrode(C-PSCs)achieve an efficiency of18.27%,which is among the highest-reported values for inorganic C-PSCs,and stability of 500 h at 85℃with 65%efficiency maintenance.
基金This work was partially supported by the National Natural Science Foundation of China(No.U1713218)the National Key R&D Program of China(No.2018YFB1307700).
文摘Throat cancer treatment involves surgical removal of the tumor,leaving patients with facial disfigurement as well as temporary or permanent loss of voice.Surface electromyography(sEMG)generated from the jaw contains lots of voice information.However,it is difficult to record because of not only the weakness of the signals but also the steep skin curvature.This paper demonstrates the design of an imperceptible,flexible epidermal sEMG tattoo-like patch with the thickness of less than 10μm and peeling strength of larger than 1N cm−1 that exhibits large adhesiveness to complex biological surfaces and is thus capable of sEMG recording for silent speech recognition.When a tester speaks silently,the patch shows excellent performance in recording the sEMG signals from three muscle channels and recognizing those frequently used instructions with high accuracy by using the wavelet decomposition and pattern recognization.The average accuracy of action instructions can reach up to 89.04%,and the average accuracy of emotion instructions is as high as 92.33%.To demonstrate the functionality of tattoo-like patches as a new human–machine interface(HMI)for patients with loss of voice,the intelligent silent speech recognition,voice synthesis,and virtual interaction have been implemented,which are of great importance in helping these patients communicate with people and make life more enjoyable.
基金This work was funded by the National Natural Science Foundation of China(Nos.61773372,62173240 and 62073229)the National Key Research and Development Program of China(2018YFB1307700)the Jiangsu Province Outstanding Youth Foundation(No.BK20160058)。
文摘Pulse diagnosis is an irreplaceable part of traditional Chinese medical science.However,application of the traditional pulse monitoring method was restricted in the modernization of Chinese medical science since it was difficult to capture real signals and integrate obscure feelings with a modern data platform.Herein,a novel multichannel pulse monitoring platform based on traditional Chinese medical science pulse theory and wearable electronics was proposed.The pulse sensing platform simultaneously detected pulse conditions at three pulse positions(Chi,Cun,and Guan).These signals were fitted to smooth surfaces to enable 3-dimensional pulse mapping,which vividly revealed the shape of the pulse length and width and compensated for the shortcomings of traditional single-point pulse sensors.Moreover,the pulse sensing system could measure the pulse signals from different individuals with different conditions and distinguish the differences in pulse signals.In addition,this system could provide full information on the temporal and spatial dimensions of a person’s pulse waveform,which is similar to the true feelings of doctors’fingertips.This innovative,cost-effective,easily designed pulse monitoring platform based on flexible pressure sensor arrays may provide novel applications in modernization of Chinese medical science or intelligent health care.
基金National Key Research and Development Program of China(2020YFA0804000)Strategic Priority Research Program of the Chinese Academy of Sciences(XDA16010000)+5 种基金CAS Project for Young Scientists in Basic Research(YSBR-076,YSBR-012)National Natural Science Foundation of China(81921006,92149301,92168201,92049116,32121001,82100140,31970597)National Key Research and Development Program of China(2020YFA08034012019YFA0802202)Program of the Beijing Natural Science Foundation(Z190019)Tencent Foundation(2021–1045),K.C.Wong Education Foundation(GJTD-2019-08),Youth Innovation Promotion Association of CAS(E1CAZW0401)Science&Technology Innovation 2030 of The Ministry of Science and Technology of China(2022ZD0214200).
文摘Aging is accompanied by the decline of organismal functions and a series of prominent hallmarks,including genetic and epigenetic alterations.These aging-associated epigenetic changes include DNA methylation,histone modification,chromatin remodeling,non-coding RNA(ncRNA)regulation,and RNA modification,all of which participate in the regulation of the aging process,and hence contribute to aging-related diseases.Therefore,understanding the epigenetic mechanisms in aging will provide new avenues to develop strategies to delay aging.Indeed,aging interventions based on manipulating epigenetic mechanisms have led to the alleviation of aging or the extension of the lifespan in animal models.Small molecule-based therapies and reprogramming strategies that enable epigenetic rejuvenation have been developed for ameliorating or reversing aging-related conditions.In addition,adopting health-promoting activities,such as caloric restriction,exercise,and calibrating circadian rhythm,has been demonstrated to delay aging.Furthermore,various clinical trials for aging intervention are ongoing,providing more evidence of the safety and efficacy of these therapies.Here,we review recent work on the epigenetic regulation of aging and outline the advances in intervention strategies for aging and age-associated diseases.A better understanding of the critical roles of epigenetics in the aging process will lead to more clinical advances in the prevention of human aging and therapy of aging-related diseases.
基金supported by the National Natural Science Foundation of China(grant nos.51925503,U1713218)the Program for HUST Academic Frontier Youth Team.
文摘The internal availability of silent speech serves as a translator for people with aphasia and keeps human–machine/human interactions working under various disturbances.This paper develops a silent speech strategy to achieve all-weather,natural interactions.The strategy requires few usage specialized skills like sign language but accurately transfers high-capacity information in complicated and changeable daily environments.In the strategy,the tattoo-like electronics imperceptibly attached on facial skin record high-quality bio-data of various silent speech,and the machine-learning algorithm deployed on the cloud recognizes accurately the silent speech and reduces the weight of the wireless acquisition module.A series of experiments show that the silent speech recognition system(SSRS)can enduringly comply with large deformation(~45%)of faces by virtue of the electricitypreferred tattoo-like electrodes and recognize up to 110 words covering daily vocabularies with a high average accuracy of 92.64%simply by use of small-sample machine learning.We successfully apply the SSRS to 1-day routine life,including daily greeting,running,dining,manipulating industrial robots in deafening noise,and expressing in darkness,which shows great promotion in real-world applications.