Undoubtedly,the enormous progress observed in recent years in the Ni-rich layered cathode materials has been crucial in terms of pushing boundaries of the Li-ion battery(LIB)technology.The achieved improvements in the...Undoubtedly,the enormous progress observed in recent years in the Ni-rich layered cathode materials has been crucial in terms of pushing boundaries of the Li-ion battery(LIB)technology.The achieved improvements in the energy density,cyclability,charging speed,reduced costs,as well as safety and stability,already contribute to the wider adoption of LIBs,which extends nowadays beyond mobile electronics,power tools,and electric vehicles,to the new range of applications,including grid storage solutions.With numerous published papers and broad reviews already available on the subject of Ni-rich oxides,this review focuses more on the most recent progress and new ideas presented in the literature references.The covered topics include doping and composition optimization,advanced coating,concentration gradient and single crystal materials,as well as innovations concerning new electrolytes and their modification,with the application of Ni-rich cathodes in solid-state batteries also discussed.Related cathode materials are briefly mentioned,with the high-entropy approach and zero-strain concept presented as well.A critical overview of the still unresolved issues is given,with perspectives on the further directions of studies and the expected gains provided.展开更多
Atmospheric chemistry research has been growing rapidly in China in the last 25 years since the concept of the“air pollution complex”was first proposed by Professor Xiaoyan TANG in 1997.For papers published in 2021 ...Atmospheric chemistry research has been growing rapidly in China in the last 25 years since the concept of the“air pollution complex”was first proposed by Professor Xiaoyan TANG in 1997.For papers published in 2021 on air pollution(only papers included in the Web of Science Core Collection database were considered),more than 24000 papers were authored or co-authored by scientists working in China.In this paper,we review a limited number of representative and significant studies on atmospheric chemistry in China in the last few years,including studies on(1)sources and emission inventories,(2)atmospheric chemical processes,(3)interactions of air pollution with meteorology,weather and climate,(4)interactions between the biosphere and atmosphere,and(5)data assimilation.The intention was not to provide a complete review of all progress made in the last few years,but rather to serve as a starting point for learning more about atmospheric chemistry research in China.The advances reviewed in this paper have enabled a theoretical framework for the air pollution complex to be established,provided robust scientific support to highly successful air pollution control policies in China,and created great opportunities in education,training,and career development for many graduate students and young scientists.This paper further highlights that developing and low-income countries that are heavily affected by air pollution can benefit from these research advances,whilst at the same time acknowledging that many challenges and opportunities still remain in atmospheric chemistry research in China,to hopefully be addressed over the next few decades.展开更多
Owing to the largely improved facilities and working conditions, solar physics research in China has recently shown marked development. This paper reports on the recent progress of solar physics research in China'...Owing to the largely improved facilities and working conditions, solar physics research in China has recently shown marked development. This paper reports on the recent progress of solar physics research in China's Mainland, mainly focusing on several hot issues, including instrumentations, magnetic field observations and research, solar flares, filaments and their eruptions, coronal mass ejections and related processes, as well as active regions and the corona, small-scale phenomena, solar activity and its predictions. A vision of the future is also described.展开更多
Serious hearing and balance impairments can occur as a result of loss of hair cells related to aging, environmental stresses(such as noises exposure) or exposure to chemotherapeutic drugs(such as cisplatin and aminogl...Serious hearing and balance impairments can occur as a result of loss of hair cells related to aging, environmental stresses(such as noises exposure) or exposure to chemotherapeutic drugs(such as cisplatin and aminoglycoside antibiotics). Because a large portion of hearing impairment involves loss of hair cells, regeneration or replacement of these cells is a possible alternative to prosthetic devices1. Researchers have paid hot attention to the study of inner ear hair cell regeneration for hearing restoration for many years. Besides the important function of hair cells, there are many other contributors essential for normal hearing. Hair cell regeneration is one of the essential steps for total hearing recovery, but not the only one. In this article, we will review the progresses in research on hearing loss, stem cell application and hearing restoration.展开更多
During the recent four decades since 1980,a series of modern climate satellites were launched,allowing for the measurement and record-keeping of multiple climate parameters,especially over the polar regions where trad...During the recent four decades since 1980,a series of modern climate satellites were launched,allowing for the measurement and record-keeping of multiple climate parameters,especially over the polar regions where traditional observations are difficult to obtain.China has been actively engaging in polar expeditions.Many observations were conducted during this period,accompanied by improved Earth climate models,leading to a series of insightful understandings concerning Arctic and Antarctic climate changes.Here,we review the recent progress China has made concerning Arctic and Antarctic climate change research over the past decade.The Arctic temperature increase is much higher than the global-mean warming rate,associated with a rapid decline in sea ice,a phenomenon called the Arctic Amplification.The Antarctic climate changes showed a zonally asymmetric pattern over the past four decades,with most of the fastest changes occurring over West Antarctica and the Antarctic Peninsula.The Arctic and Antarctic climate changes were driven by anthropogenic greenhouse gas emissions and ozone loss,while tropical-polar teleconnections play important roles in driving the regional climate changes and extreme events over the polar regions.Polar climate changes may also feedback to the entire Earth climate system.The adjustment of the circulation in both the troposphere and the stratosphere contributed to the interactions between the polar climate changes and lower latitudes.Climate change has also driven rapid Arctic and Southern ocean acidification.Chinese researchers have made a series of advances in understanding these processes,as reviewed in this paper.展开更多
Na-ion batteries(NIBs) have been attracting growing interests in recent years with the increasing demand of energy storage owing to their dependence on more abundant Na than Li. The exploration of the industrializatio...Na-ion batteries(NIBs) have been attracting growing interests in recent years with the increasing demand of energy storage owing to their dependence on more abundant Na than Li. The exploration of the industrialization of NIBs is also on the march, where some challenges are still limiting its step. For instance, the relatively low initial Coulombic efficiency(ICE) of anode can cause undesired energy density loss in the full cell. In addition to the strategies from the sight of materials design that to improve the capacity and ICE of electrodes, presodiation technique is another important method to efficiently offset the irreversible capacity and enhance the energy density. Meanwhile, the slow release of the extra Na during the cycling is able to improve the cycling stability.In this review, we would like to provide a general insight of presodiation technique for high-performance NIBs.The recent research progress including the principles and strategies of presodiation will be introduced, and some remaining challenges as well as our perspectives will be discussed. This review aims to exhibit the basic knowledge of presodiation to inspire the researchers for future studies.展开更多
Five catalytic processes and their catalysts will be introduced in my talk. Firstly,the demonstration test(3000 ton/a)results using a novel catalyst Co/SiO2 with egg-shell structure and the strategies for this catalys...Five catalytic processes and their catalysts will be introduced in my talk. Firstly,the demonstration test(3000 ton/a)results using a novel catalyst Co/SiO2 with egg-shell structure and the strategies for this catalyst preparation based on the issues from the mass transfer of produced wax from F-T synthesis will be discussed. Recent progresses on C2-oxygenate synthesis from syngas over a Rh/SiO2 catalyst and a 10 thousands ton/a demonstration test facility in China will be built in 2010 will be reported in the second section. A naphtha and diesel distillate which cut off the heavier end of S-F-A distribution direct synthesis with low methane selectivity from syngas over a Co/AC1 catalyst and a 10000 ton/a demonstration test with a bubble column slurry reactor will be talked about in this speech. A high α-alcohols of C2-C18 direct synthesis with more than 50 wt% selectivity and low methane and methanol selectivities from syngas over a Co2C/AC2 catalyst,a 3000 ton/a demonstration test with a bubble column slurry reactor and the primary fundamental understandings will be detailedly discussed in the forth section. In situ formation of homogeneous active sites on the surface of supported Rh heterogeneous catalysts and their application in hydroformylation of olefins will be introduced in fifth section.展开更多
This paper summarizes main progresses made in tropical cyclone research field in China in the past few years after the 8th five year program of China. New achievements have been made on tropical cyclone (hereafter ref...This paper summarizes main progresses made in tropical cyclone research field in China in the past few years after the 8th five year program of China. New achievements have been made on tropical cyclone (hereafter referred as TC) structure, numerical prediction, evaluation of operational numerical model, TC–caused heavy rain, TC climate features and disasters, etc.展开更多
With the emergence and development of wearable devices,the novel ene rgy storage systems with flexible feature and high energy density are urgently needed.As we all know,for next generation high energystorage systems,...With the emergence and development of wearable devices,the novel ene rgy storage systems with flexible feature and high energy density are urgently needed.As we all know,for next generation high energystorage systems,lithium-sulfur(Li-S) batteries with a high theoretical capacity are regarded as one of the most promising candidates.In addition,the flexible Li-S batteries have received more and more attention.The determined factor in the flexible Li-S batteries is how to design the foldable electrodes including both anode and cathode.As for the flexible sulfur cathode,it could be obtained by integrating the electroactive sulfur with a flexible substrate,generally.In recent years,the flexible cathode of Li-S batteries have made considerable progress,however there are also many huge challenges needing to overcome,such as low content of sulfur,fast decrease of capacity and short cycle life.In this paper,the current develop status of flexible cathodes of Li-S batteries have been summarized,and the future trend also be pointed out.展开更多
Photonic crystal fibers are attractive since we can realize a wide variety of unique features in the PCFs, which cannot be realized in conventional single-mode fibers. We describe recent progress in the PCF.
In 2012, we published the first special issue on mechanisms of pain and itch in Neuroscience Bulletin, which covered the peripheral, central, and glial mechanisms of pain and itch [1-5]. In the last 5 years, the field...In 2012, we published the first special issue on mechanisms of pain and itch in Neuroscience Bulletin, which covered the peripheral, central, and glial mechanisms of pain and itch [1-5]. In the last 5 years, the field has seen tremendous progress in the molecular and functional characterization of primary sensory neurons [6, 7], neurocircuits of pain and itch [8-10], immune and glial modulation of pain and itch [11-15], molecular mechanisms of pain [16, 17], and identification of brain signatures of pain [18]. Thus, it is timely to highlight the recent progress in a second special issue. I invited the previous authors and new authors from China, the USA, and Japan, and they have contributed 20 mini-reviews and original articles to this special issue.展开更多
Severe brain injury can lead to disorders of consciousness (DOCs). Since DOC patients cannot communicate functionally or behave purposefully, most remain bedridden and require laborious care. The medical community i...Severe brain injury can lead to disorders of consciousness (DOCs). Since DOC patients cannot communicate functionally or behave purposefully, most remain bedridden and require laborious care. The medical community is often confronted with the expectations of the families of chronic DOC patients, and the social, economic, and ethical consequences are tremendous. Research on DOCs is attracting increasing attention from scientists and physicians in various fields. With the development of modern neuroimaging and neuromodulation techniques, much progress has been made in the diagnosis, prognosis, treatment, and rehabilitation of DOCs in the last decade.展开更多
The progress achieved on power scaling and compact and portable THz sources is reviewed.By reversely stacking the GaP plates,the photon conversion efficiency is improved from 25% to 40% which corresponds to the maximu...The progress achieved on power scaling and compact and portable THz sources is reviewed.By reversely stacking the GaP plates,the photon conversion efficiency is improved from 25% to 40% which corresponds to the maximum value.When the number of the plates is increased from four to five,the output power decreases because of back conversion.The THz generation is also investigated by mixing the two frequencies generated by a single Nd:YLF solid-state laser.The average output power reaches 1 μW.The introduction of two Nd:YLF crystals significantly improves the output power to 4.5 μW.This configuration facilitates the generation of different output frequencies.展开更多
1 Introduction As environmental pollution continues to worsen,governments are increasing their efforts to develop green transport vehicles,such as electric vehicles and hybrid cars.
The trends of fiber-based optical component technologies are reviewed focusing on fused-taper couplers and fiber Bragg gratings for high bit-rate DWDM transmission systems.
This paper reviews recent progress of advanced optical fibers that are expected to be as candidates for the future trunk-line systems, metropolitan networks and access lines for subscribers.
Various optical fiber connectors have been developed during the 20 years since optical fiber communications systems were first put into practical use. This paper describes the technical background and recent issues re...Various optical fiber connectors have been developed during the 20 years since optical fiber communications systems were first put into practical use. This paper describes the technical background and recent issues related to photonic connection technologies.展开更多
The Drought, Flood and Waterlogging Damage (DFWD) study is related to many subjects such as meteorology and climatology, hydrology, geography, and agricultural science In the aforementioned subjects, substantial work ...The Drought, Flood and Waterlogging Damage (DFWD) study is related to many subjects such as meteorology and climatology, hydrology, geography, and agricultural science In the aforementioned subjects, substantial work has been done on DFWD study by a lot of researchers from the views of their specialities This paper tries to introduce the recent progress on the field Four main problems are referred to the DFWD study, they are as following: (1) The change sequence in historical period The historical data must be quantatitively processed For this purpose, many schemes were suggested in the past years Studies of the historical DFWD have been emphasized in the last fivehundred years as well as the other time scales (2) The mechanism and trigger event Natural disasters are related to factors disastrous to human activities in the evolution of physical environment, and they can reflect natural features of constitution of the physical environment The factors include the monsoon circulation, the sea tempereature effects, the ENSO, and the others (3) The loss estimation The DFWD is not a pure meteorological damage, and it is also a complex ecological damage The ecological effects, crop influences and other socialenvironment features will be considered on the estimation of DFWD loss (4) The measures of prevention and control Many forecast models are developed, and the measures of prevention and control are suggested, ie, the adoption of measures combining engineering techniques with biological measurres In the past years, advances have been made in those four aspects展开更多
基金supported by the program“Excellence Initiative-Research University”for the AGH University of Krakow(IDUB AGH,No.501.696.7996,Action 4,ID 6354)partially supported by the AGH University of Krakow under No.16.16.210.476.
文摘Undoubtedly,the enormous progress observed in recent years in the Ni-rich layered cathode materials has been crucial in terms of pushing boundaries of the Li-ion battery(LIB)technology.The achieved improvements in the energy density,cyclability,charging speed,reduced costs,as well as safety and stability,already contribute to the wider adoption of LIBs,which extends nowadays beyond mobile electronics,power tools,and electric vehicles,to the new range of applications,including grid storage solutions.With numerous published papers and broad reviews already available on the subject of Ni-rich oxides,this review focuses more on the most recent progress and new ideas presented in the literature references.The covered topics include doping and composition optimization,advanced coating,concentration gradient and single crystal materials,as well as innovations concerning new electrolytes and their modification,with the application of Ni-rich cathodes in solid-state batteries also discussed.Related cathode materials are briefly mentioned,with the high-entropy approach and zero-strain concept presented as well.A critical overview of the still unresolved issues is given,with perspectives on the further directions of studies and the expected gains provided.
基金funded by the National Natural Science Foundation of China(Grant No.91844000)。
文摘Atmospheric chemistry research has been growing rapidly in China in the last 25 years since the concept of the“air pollution complex”was first proposed by Professor Xiaoyan TANG in 1997.For papers published in 2021 on air pollution(only papers included in the Web of Science Core Collection database were considered),more than 24000 papers were authored or co-authored by scientists working in China.In this paper,we review a limited number of representative and significant studies on atmospheric chemistry in China in the last few years,including studies on(1)sources and emission inventories,(2)atmospheric chemical processes,(3)interactions of air pollution with meteorology,weather and climate,(4)interactions between the biosphere and atmosphere,and(5)data assimilation.The intention was not to provide a complete review of all progress made in the last few years,but rather to serve as a starting point for learning more about atmospheric chemistry research in China.The advances reviewed in this paper have enabled a theoretical framework for the air pollution complex to be established,provided robust scientific support to highly successful air pollution control policies in China,and created great opportunities in education,training,and career development for many graduate students and young scientists.This paper further highlights that developing and low-income countries that are heavily affected by air pollution can benefit from these research advances,whilst at the same time acknowledging that many challenges and opportunities still remain in atmospheric chemistry research in China,to hopefully be addressed over the next few decades.
基金supported by the National Natural Science Foundation of China (NSFC, Grant Nos. 10878002, 10610099, 10933003 and 10673004)the National Basic Research Program of China (973 program, 2011CB811402)
文摘Owing to the largely improved facilities and working conditions, solar physics research in China has recently shown marked development. This paper reports on the recent progress of solar physics research in China's Mainland, mainly focusing on several hot issues, including instrumentations, magnetic field observations and research, solar flares, filaments and their eruptions, coronal mass ejections and related processes, as well as active regions and the corona, small-scale phenomena, solar activity and its predictions. A vision of the future is also described.
基金the Beijing Scienceand Technology NOVA program Grant (No.2006B53)the Peking Union Medical CollegeHospital Junior Researcher Grant.
文摘Serious hearing and balance impairments can occur as a result of loss of hair cells related to aging, environmental stresses(such as noises exposure) or exposure to chemotherapeutic drugs(such as cisplatin and aminoglycoside antibiotics). Because a large portion of hearing impairment involves loss of hair cells, regeneration or replacement of these cells is a possible alternative to prosthetic devices1. Researchers have paid hot attention to the study of inner ear hair cell regeneration for hearing restoration for many years. Besides the important function of hair cells, there are many other contributors essential for normal hearing. Hair cell regeneration is one of the essential steps for total hearing recovery, but not the only one. In this article, we will review the progresses in research on hearing loss, stem cell application and hearing restoration.
基金supported by the National Key Research and Development Program of China(2018YFA 0605703)the National Natural Science Foundation of China(No.41976193 and No.42176243)+8 种基金X.CHEN was supported by the National Key Research and Development Program of China(2019YFC1509100)the National Science Foundation of China(No.41825012)B.WU was supported by the Major Program of the National Natural Science Foundation of China(41790472)the National Key Basic Research Project of China(2019YFA0607002)the National Natural Science Foundation of China(41730959)X.CHENG was funded by the Innovation Group Project of Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(Grant No.311021008)M.DING was supported by the National Natural Science Foundation of China(42122047 and 42105036)the Basic Research Fund of the Chinese Academy of Meteorological Sciences(2021Y021 and 2021Z006)Q.SUN was supported by the National Key R&D Program of China(No.2022YFE0106300).
文摘During the recent four decades since 1980,a series of modern climate satellites were launched,allowing for the measurement and record-keeping of multiple climate parameters,especially over the polar regions where traditional observations are difficult to obtain.China has been actively engaging in polar expeditions.Many observations were conducted during this period,accompanied by improved Earth climate models,leading to a series of insightful understandings concerning Arctic and Antarctic climate changes.Here,we review the recent progress China has made concerning Arctic and Antarctic climate change research over the past decade.The Arctic temperature increase is much higher than the global-mean warming rate,associated with a rapid decline in sea ice,a phenomenon called the Arctic Amplification.The Antarctic climate changes showed a zonally asymmetric pattern over the past four decades,with most of the fastest changes occurring over West Antarctica and the Antarctic Peninsula.The Arctic and Antarctic climate changes were driven by anthropogenic greenhouse gas emissions and ozone loss,while tropical-polar teleconnections play important roles in driving the regional climate changes and extreme events over the polar regions.Polar climate changes may also feedback to the entire Earth climate system.The adjustment of the circulation in both the troposphere and the stratosphere contributed to the interactions between the polar climate changes and lower latitudes.Climate change has also driven rapid Arctic and Southern ocean acidification.Chinese researchers have made a series of advances in understanding these processes,as reviewed in this paper.
基金Supported by the National Natural Science Foundation of China (NSFC)(Grant Nos. 51725206 and 52072403)the NSFCUK-RI EPSRC (Grant No. 51861165201)+4 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA21070500)the Youth Innovation Promotion Association of the Chinese Academy of Sciences (Grant No. 2020006)the Beijing Municipal Natural Science Foundation (Grant No. 2212022)the Youth Innovation Promotion Association,Chinese Academy of Sciences (Grant No. 2020006)China Postdoctoral Science Foundation founded Project (Grant No. 2021M693367)。
文摘Na-ion batteries(NIBs) have been attracting growing interests in recent years with the increasing demand of energy storage owing to their dependence on more abundant Na than Li. The exploration of the industrialization of NIBs is also on the march, where some challenges are still limiting its step. For instance, the relatively low initial Coulombic efficiency(ICE) of anode can cause undesired energy density loss in the full cell. In addition to the strategies from the sight of materials design that to improve the capacity and ICE of electrodes, presodiation technique is another important method to efficiently offset the irreversible capacity and enhance the energy density. Meanwhile, the slow release of the extra Na during the cycling is able to improve the cycling stability.In this review, we would like to provide a general insight of presodiation technique for high-performance NIBs.The recent research progress including the principles and strategies of presodiation will be introduced, and some remaining challenges as well as our perspectives will be discussed. This review aims to exhibit the basic knowledge of presodiation to inspire the researchers for future studies.
文摘Five catalytic processes and their catalysts will be introduced in my talk. Firstly,the demonstration test(3000 ton/a)results using a novel catalyst Co/SiO2 with egg-shell structure and the strategies for this catalyst preparation based on the issues from the mass transfer of produced wax from F-T synthesis will be discussed. Recent progresses on C2-oxygenate synthesis from syngas over a Rh/SiO2 catalyst and a 10 thousands ton/a demonstration test facility in China will be built in 2010 will be reported in the second section. A naphtha and diesel distillate which cut off the heavier end of S-F-A distribution direct synthesis with low methane selectivity from syngas over a Co/AC1 catalyst and a 10000 ton/a demonstration test with a bubble column slurry reactor will be talked about in this speech. A high α-alcohols of C2-C18 direct synthesis with more than 50 wt% selectivity and low methane and methanol selectivities from syngas over a Co2C/AC2 catalyst,a 3000 ton/a demonstration test with a bubble column slurry reactor and the primary fundamental understandings will be detailedly discussed in the forth section. In situ formation of homogeneous active sites on the surface of supported Rh heterogeneous catalysts and their application in hydroformylation of olefins will be introduced in fifth section.
基金This work is supported by National Natural Science Foundation of China under Grant Nos. 49975013 and 40175019.
文摘This paper summarizes main progresses made in tropical cyclone research field in China in the past few years after the 8th five year program of China. New achievements have been made on tropical cyclone (hereafter referred as TC) structure, numerical prediction, evaluation of operational numerical model, TC–caused heavy rain, TC climate features and disasters, etc.
基金This work was financially supported by the National Natural Science Foundation of China(No.51771076)the Innovative Research Groups of the National Natural Science Foundation of China(No.NSFC51621001)+2 种基金the“1000 plan”from Chinese Governmentthe Guangdong“Pearl River Talents Plan”(No.2017GC010218)the Guangzhou Science and Technology Plan Projects(No.201804010104)。
文摘With the emergence and development of wearable devices,the novel ene rgy storage systems with flexible feature and high energy density are urgently needed.As we all know,for next generation high energystorage systems,lithium-sulfur(Li-S) batteries with a high theoretical capacity are regarded as one of the most promising candidates.In addition,the flexible Li-S batteries have received more and more attention.The determined factor in the flexible Li-S batteries is how to design the foldable electrodes including both anode and cathode.As for the flexible sulfur cathode,it could be obtained by integrating the electroactive sulfur with a flexible substrate,generally.In recent years,the flexible cathode of Li-S batteries have made considerable progress,however there are also many huge challenges needing to overcome,such as low content of sulfur,fast decrease of capacity and short cycle life.In this paper,the current develop status of flexible cathodes of Li-S batteries have been summarized,and the future trend also be pointed out.
文摘Photonic crystal fibers are attractive since we can realize a wide variety of unique features in the PCFs, which cannot be realized in conventional single-mode fibers. We describe recent progress in the PCF.
文摘In 2012, we published the first special issue on mechanisms of pain and itch in Neuroscience Bulletin, which covered the peripheral, central, and glial mechanisms of pain and itch [1-5]. In the last 5 years, the field has seen tremendous progress in the molecular and functional characterization of primary sensory neurons [6, 7], neurocircuits of pain and itch [8-10], immune and glial modulation of pain and itch [11-15], molecular mechanisms of pain [16, 17], and identification of brain signatures of pain [18]. Thus, it is timely to highlight the recent progress in a second special issue. I invited the previous authors and new authors from China, the USA, and Japan, and they have contributed 20 mini-reviews and original articles to this special issue.
文摘Severe brain injury can lead to disorders of consciousness (DOCs). Since DOC patients cannot communicate functionally or behave purposefully, most remain bedridden and require laborious care. The medical community is often confronted with the expectations of the families of chronic DOC patients, and the social, economic, and ethical consequences are tremendous. Research on DOCs is attracting increasing attention from scientists and physicians in various fields. With the development of modern neuroimaging and neuromodulation techniques, much progress has been made in the diagnosis, prognosis, treatment, and rehabilitation of DOCs in the last decade.
基金supported by the U.S. National Science Foundation
文摘The progress achieved on power scaling and compact and portable THz sources is reviewed.By reversely stacking the GaP plates,the photon conversion efficiency is improved from 25% to 40% which corresponds to the maximum value.When the number of the plates is increased from four to five,the output power decreases because of back conversion.The THz generation is also investigated by mixing the two frequencies generated by a single Nd:YLF solid-state laser.The average output power reaches 1 μW.The introduction of two Nd:YLF crystals significantly improves the output power to 4.5 μW.This configuration facilitates the generation of different output frequencies.
基金supported by the National Science Foundation of China(51502009,51532001,21675109)the National Key Basic Research Program of China(2014CB31802)the Science Foundation of Henan province(162300410209)
文摘1 Introduction As environmental pollution continues to worsen,governments are increasing their efforts to develop green transport vehicles,such as electric vehicles and hybrid cars.
文摘The trends of fiber-based optical component technologies are reviewed focusing on fused-taper couplers and fiber Bragg gratings for high bit-rate DWDM transmission systems.
文摘This paper reviews recent progress of advanced optical fibers that are expected to be as candidates for the future trunk-line systems, metropolitan networks and access lines for subscribers.
文摘Various optical fiber connectors have been developed during the 20 years since optical fiber communications systems were first put into practical use. This paper describes the technical background and recent issues related to photonic connection technologies.
文摘The Drought, Flood and Waterlogging Damage (DFWD) study is related to many subjects such as meteorology and climatology, hydrology, geography, and agricultural science In the aforementioned subjects, substantial work has been done on DFWD study by a lot of researchers from the views of their specialities This paper tries to introduce the recent progress on the field Four main problems are referred to the DFWD study, they are as following: (1) The change sequence in historical period The historical data must be quantatitively processed For this purpose, many schemes were suggested in the past years Studies of the historical DFWD have been emphasized in the last fivehundred years as well as the other time scales (2) The mechanism and trigger event Natural disasters are related to factors disastrous to human activities in the evolution of physical environment, and they can reflect natural features of constitution of the physical environment The factors include the monsoon circulation, the sea tempereature effects, the ENSO, and the others (3) The loss estimation The DFWD is not a pure meteorological damage, and it is also a complex ecological damage The ecological effects, crop influences and other socialenvironment features will be considered on the estimation of DFWD loss (4) The measures of prevention and control Many forecast models are developed, and the measures of prevention and control are suggested, ie, the adoption of measures combining engineering techniques with biological measurres In the past years, advances have been made in those four aspects