Rapid technological advancements drive miniaturization and high energy density in devices,thereby increasing nanoscale thermal management demands and urging development of higher spatial resolution technologies for th...Rapid technological advancements drive miniaturization and high energy density in devices,thereby increasing nanoscale thermal management demands and urging development of higher spatial resolution technologies for thermal imaging and transport research.Here,we introduce an approach to measure nanoscale thermal resistance using in situ inelastic scanning transmission electron microscopy.By constructing unidirectional heating flux with controlled temperature gradients and analyzing electron energy-loss/gain signals under optimized acquisition conditions,nanometer-resolution in mapping phonon apparent temperature is achieved.Thus,interfacial thermal resistance is determined by calculating the ratio of interfacial temperature difference to bulk temperature gradient.This methodology enables direct measurement of thermal transport properties for atomic-scale structural features(e.g.,defects and heterointerfaces),resolving critical structure-performance relationships,providing a useful tool for investigating thermal phenomena at the(sub-)nanoscale.展开更多
The construction of advanced laboratories for precision instruments, such as electron microscopes, involves unique challenges that are influenced by the specific environmental conditions required for optimal functiona...The construction of advanced laboratories for precision instruments, such as electron microscopes, involves unique challenges that are influenced by the specific environmental conditions required for optimal functionality. These include mitigating interference from magnetic fields and vibrations, which are critical for maintaining the precision and accuracy of the instruments used. This study aims to offer enhanced project management strategies and detailed construction solutions that address the environmental and technical needs specific to electron microscopy labs, thereby facilitating effective lab operations and extending the lifecycle of high-end precision instruments. Case studies of existing laboratory constructions, onsite investigations, and comprehensive reviews of the technical and environmental requirements provide the basis for a best practice for constructing sophisticated electron microscopy labs. The approach integrates both pre-construction planning and post-construction adjustments to create optimal operational environments. The findings suggest that successful lab constructions are those that incorporate thorough onsite assessments, strategic location choices, and the use of advanced construction materials and techniques specifically designed to counteract environmental challenges like magnetic and vibration interferences. Actionable guidelines for both planning and executing the construction of electron microscope labs highlighted in this tutorial are intended as an important resource to troubleshoot or upgrade existing lab facilities and to consult in preparation of future lab construction projects.展开更多
Changes of calmodulin (CaM) distribution in the embryo sac of rice (Oryza sativa subsp. Japonica) at various stages before and after fertilization have been investigated by using immunogold electron microscopy. Before...Changes of calmodulin (CaM) distribution in the embryo sac of rice (Oryza sativa subsp. Japonica) at various stages before and after fertilization have been investigated by using immunogold electron microscopy. Before pollination, both cytoplasm and vacuoles of the egg cell, synergids and central cell were labeled by gold particles. A small amount of gold particles were localized in the nucleus, endoplasmic reticulum, mitochondria and dictyosomes. From pollination to fertilization, CaM amount increased in these cells, especially rich in the starch of amyloplasts. Increase of gold particles in the central cell began about 2 h earlier than that in the egg cell. There was no distinct difference of CaM amount between the degenerated and the persistent synergids. It is interesting to observe an obvious change of CaM distribution form during pollination and fertilization from scattered single particles to clustered particles, and back again to single particles after the fertilization finished. CaM was also localized extracellularly in the embryo sac wall as well as in the wall and intercellular space of nucellus cells. The extracellular CaM also changes in its amount and form after pollination. These results suggest that CaM, either intra- or extra-cellular, may play important roles in fertilization and zygote formation.展开更多
To gain further understanding of the luminescence properties of multiquantum wells and the factors affecting them on a microscopic level,cathodoluminescence combined with scanning transmission electron microscopy and ...To gain further understanding of the luminescence properties of multiquantum wells and the factors affecting them on a microscopic level,cathodoluminescence combined with scanning transmission electron microscopy and spectroscopy was used to measure the luminescence of In_(0.15)Ga_(0.85)N five-period multiquantum wells.The lattice-composition-energy relationship was established with the help of energy-dispersive x-ray spectroscopy,and the bandgaps of In_(0.15)Ga_(0.85)N and GaN in multiple quantum wells were extracted by electron energy loss spectroscopy to understand the features of cathodoluminescence spectra.The luminescence differences between different periods of multiquantum wells and the effects of defects such as composition fluctuation and dislocations on the luminescence of multiple quantum wells were revealed.Our study establishing the direct relationship between the atomic structure of In_(x)Ga_(1-x)N multiquantum wells and photoelectric properties provides useful information for nitride applications.展开更多
[Objective]The experiment aimed to explore a new way for observing surface structure of Nostoc sphaeroides Kutzing. [Method] The scanning electron microscope was used to observe the epidermal ultrastructure of wild an...[Objective]The experiment aimed to explore a new way for observing surface structure of Nostoc sphaeroides Kutzing. [Method] The scanning electron microscope was used to observe the epidermal ultrastructure of wild and cultured Nostoc sphaeroides Kutzing. [ Result] The epidermis of wild and cultured Nostoc sphaeroides Kutzing showed mixture structure of fibril colloid which was reticular arranged. The difference between wild and cultured Nostoc sphaeroides Kutzing was that the outer epidermis of cultured Nostoc sphaeroides Kutzing had trichome distribution but the wild Nostoc sphaeroides Kutzing did not has such distribution. The obsevation results of under smaller than 10 μm by scanning electron microscope was touched thick and showed many folds and distortions. [ Conclusion] The scanning electron microscope was an effective way to study development of Nostoc sphaeroides Kutzing colony and it was worth popularizing.展开更多
Li–CO_(2)/O_(2)batteries,a promising energy storage technology,not only provide ultrahigh discharge capacity but also capture CO_(2)and turn it into renewable energy.Their electrochemical reaction pathways'ambigu...Li–CO_(2)/O_(2)batteries,a promising energy storage technology,not only provide ultrahigh discharge capacity but also capture CO_(2)and turn it into renewable energy.Their electrochemical reaction pathways'ambiguity,however,creates a hurdle for their practical application.This study used copper selenide(CuSe)nanosheets as the air cathode medium in an environmental transmission electron microscope to in situ study Li–CO_(2)/O_(2)(mix CO_(2)as well as O_(2)at a volume ratio of 1:1)and Li–O_(2)batteries as well as Li–CO_(2)batteries.Primary discharge reactions take place successively in the Li–CO_(2)/O_(2)–CuSe nanobattery:(I)4Li^(+)+O_(2)+4e^(−)→2Li_(2)O;(II)Li_(2)O+CO_(2)→Li_(2)CO_(3).The charge reaction proceeded via(III)2Li_(2)CO_(3)→4Li^(+)+2CO_(2)+O_(2)+4e^(−).However,Li–O_(2)and Li–CO_(2)nanobatteries showed poor cycling stability,suggesting the difficulty in the direct decomposition of the discharge product.The fluctuations of the Li–CO_(2)/O_(2)battery's electrochemistry were also shown to depend heavily on O_(2).The CuSe‐based Li–CO_(2)/O_(2)battery showed exceptional electrochemical performance.The Li^–CO_(2)/O_(2)battery offered a discharge capacity apex of 15,492 mAh g^(−1) and stable cycling 60 times at 100 mA g^(−1).Our research offers crucial insight into the electrochemical behavior of Li–CO_(2)/O_(2),Li–O_(2),and Li–CO_(2)nanobatteries,which may help the creation of high‐performance Li–CO_(2)/O_(2)batteries for energy storage applications.展开更多
[ Objective] The paper was to observe Helicotylenchus digonicus by scanning electron microscope （SEM）. [ Method ] H. digonicus collected from Changxing of Zhejiang Province was observed under scanning electron micro...[ Objective] The paper was to observe Helicotylenchus digonicus by scanning electron microscope （SEM）. [ Method ] H. digonicus collected from Changxing of Zhejiang Province was observed under scanning electron microscope, and its morphological structure was confmned under optical microscope. [ Resuit]The nematode specimens fixed by glutaraldehyde and osmium tetroxide and prepared by critical point drying were unmodified and unshrinkable with clear mor- phological structure, which could be scanned very well by scanning electron microscope. [ Conclusion ] The study provided reference for study and control of H. digonicus.展开更多
[Objective] The research aimed to provide reference for classification of pomegranate cultivars and studies of genetic relationship among pomegranate cultivars.[Method] The electron microscope scanning was used to com...[Objective] The research aimed to provide reference for classification of pomegranate cultivars and studies of genetic relationship among pomegranate cultivars.[Method] The electron microscope scanning was used to comparatively observe leaf epidermal structures of 4 pomegranate cultivars.[Result] The upper epidermal structures of 4 pomegranate cultivars were similar and showed reticular structure .However, the differences existed in lower epidermis,such as cell shape,cell size and arrangement mode of cell as well as stomatal density,while the structures of leaf vein in lower epidermis of 4 pomegranate cultivars were similar.[Conclusion] The research provided morphological references for studying heterosis of pomegranate to some extent.展开更多
Chalkiness characters affect not only the grain appearance,milling,eating and cooking qualities but also the grain nutritional quality in rice,thus it is one of the most important traits in rice. It is very important ...Chalkiness characters affect not only the grain appearance,milling,eating and cooking qualities but also the grain nutritional quality in rice,thus it is one of the most important traits in rice. It is very important for us to investigate the relation of the chalkiness formation and the development of endosperm structure and starch granule of different rice varieties. Here,we have investigated the chalkiness characters such as chalkiness rate,chalkiness degree and chalkiness area in 15 japonica rice varieties from southern Henan. Furthermore,the endosperm structure and starch granules of rice grain were also observed with scanning electron microscope. The results showed that the 15 japonica varieties have a significantly linear relationship between the chalkiness rate and chalkiness degree. Among the varieties,the biggest difference is the chalkiness rate,the second is the chalkiness area,and the last is the chalkiness degree. Moreover,there is a certain correlation between the distribution of starch granules,the arrangement of endosperm cells and the occurrence of grain chalkiness in the different rice varieties. For the same variety,the starch granules of chalky and non-chalky grains have obvious difference,while the starch granules from the transparent part of chalky rice and non-chalky rice do not have significant difference. The results would provide useful references for the improvement of grain quality in rice.展开更多
In this work,an old scanning electron microscope(SEM)is refurbished to enhance its image processing capability.How to digitally sample and process an analog image is also presented.An NI PCI-6259 multiple input/output...In this work,an old scanning electron microscope(SEM)is refurbished to enhance its image processing capability.How to digitally sample and process an analog image is also presented.An NI PCI-6259 multiple input/output data acquisition(DAQ)board is used to acquire signals originally being sent to an analog display,and then convert the signals into a digital image.Two output channels are used for raster scan of the horizontal and verticle axes of the image buffer,while one input channel is used to read the brightness signals at various coordinate points.Synchronous method is used to maximize the DAQ speed.Finally,the digitally buffered images are read out to display and saved in a hard drive.The hardware and software designs of this work are explained in great detail,which can serve as a very good example for fast synchronous DAQ,advanced virtual instrument design and structural driver programming with LabVIEW.展开更多
Lithium-rich layered oxides(LrLOs) deliver extremely high specific capacities and are considered to be promising candidates for electric vehicle and smart grid applications. However, the application of LrLOs needs fur...Lithium-rich layered oxides(LrLOs) deliver extremely high specific capacities and are considered to be promising candidates for electric vehicle and smart grid applications. However, the application of LrLOs needs further understanding of the structural complexity and dynamic evolution of monoclinic and rhombohedral phases, in order to overcome the issues including voltage decay, poor rate capability, initial irreversible capacity loss and etc. The development of aberration correction for the transmission electron microscope and concurrent progress in electron spectroscopy, have fueled rapid progress in the understanding of the mechanism of such issues. New techniques based on the transmission electron microscope are first surveyed, and the applications of these techniques for the study of the structure, migration of transition metal, and the activation of oxygen of LrLOs are then explored in detail, with a particular focus on the mechanism of voltage decay.展开更多
Specimens of Mugil soiuy were collected from the coastal waters of Bohai Sea in Tianjin. The gillfilaments were cut with fine scissors and soaked for 24h in a fixative consisting of 2.5% glutaralde-hyde in 0.1 mol lph...Specimens of Mugil soiuy were collected from the coastal waters of Bohai Sea in Tianjin. The gillfilaments were cut with fine scissors and soaked for 24h in a fixative consisting of 2.5% glutaralde-hyde in 0.1 mol lphosporic acid buffer. After three washes in a buffer solution the tissue was fixedin a mixture of 1% osmium tetraoxide at 4℃ for 1h. The tissue was dehydrated in graded ethandethanols and dried. The tissue was examined and photographed with an SEM at an accelerating voltage展开更多
A novel instrument that integrates reflection high energy electron diffraction(RHEED),electron energy loss spectroscopy(EELS),and imaging is designed and simulated.Since it can correlate the structural,elemental,and s...A novel instrument that integrates reflection high energy electron diffraction(RHEED),electron energy loss spectroscopy(EELS),and imaging is designed and simulated.Since it can correlate the structural,elemental,and spatial information of the same surface region via the simultaneously acquired patterns of RHEED,EELS,and energy-filtered electron microscopy,it is named correlative reflection electron microscopy(c-REM).Our simulation demonstrates that the spatial resolution of this c-REM is lower than 50 nm,which meets the requirements for in-situ monitoring the structural and chemical evolution of surface in advanced material.展开更多
The low-energy electron point source （LEEPS） microscope, which creates enlarged projection images with lowenergy field emission electron beams, can be used to observe the projection image of nano-scale samples and t...The low-energy electron point source （LEEPS） microscope, which creates enlarged projection images with lowenergy field emission electron beams, can be used to observe the projection image of nano-scale samples and to characterize the coherence of the field emission beam. In this paper we report the design and test operation performance of a home-made LEEPS microscope. Multi-walled carbon nanotubes （MWCNTs） synthesized by the CVD method were observed by LEEPS microscope using a conventional tungsten tip, and projection images with the magnification of up to 10^4 was obtained. The resolution of the acquired images is -10 nm. A higher resolution and a larger magnification can be expected when the AC magnetic field inside the equipment is shielded and the vibration of the instrument reduced.展开更多
The description and function characterization of a flange-on type low energy electron mi- croscope are given. In this microscope a magnetic beam separator with 10° deflection angle is used in order to facilitate ...The description and function characterization of a flange-on type low energy electron mi- croscope are given. In this microscope a magnetic beam separator with 10° deflection angle is used in order to facilitate compacting the instrument on a single 10 in. flange. Mean- while some correcting elements in the electron optical system are simplified to reduce the complexities of construction and operation. The sample is set close to ground potential, so that all the electrostatic lenses are easily to float at high voltages. The performance of the microscope in typical low energy electron microscopy, low energy electron diffraction and photoemission electron microscopy modes is demonstrated through several experiments. A lateral resolution of 51 nm is estimated for low energy electron microscopy imaging. With femtosecond laser as light source, the consequent nonlinear photoemission makes this micro-scope also suitable for the observation of optical near field phenomena and a lateral resolution of 110 nm is obtained.展开更多
The line width(often synonymously used for critical dimension,CD)is a crucial parameter in integrated circuits.To accurately control CD values in manufacturing,a reasonable CD reference material is required to calibra...The line width(often synonymously used for critical dimension,CD)is a crucial parameter in integrated circuits.To accurately control CD values in manufacturing,a reasonable CD reference material is required to calibrate the corresponding instruments.We develop a new reference material with nominal CDs of 160 nm,80 nm,and 40 nm.The line features are investigated based on the metrological scanning electron microscope which is developed by the National Institute of Metrology(NIM)in China.Also,we propose a new characterization method for the precise measurement of CD values.After filtering and leveling the intensity profiles,the line features are characterized by the combination model of the Gaussian and Lorentz functions.The left and right edges of CD are automatically extracted with the profile decomposition and k-means algorithm.Then the width of the two edges at the half intensity position is regarded as the standard CD value.Finally,the measurement results are evaluated in terms of the sample,instrument,algorithm,and repeatability.The experiments indicate efficiency of the proposed method which can be easily applied in practice to accurately characterize CDs.展开更多
Nephroselmis gaoae sp.nov.is described on the basis of light and electron microscope observations ofcultured material originally collected and isolated from seawater of Jiaozhou Bay,Qingdao,China.Theperiplasts on the ...Nephroselmis gaoae sp.nov.is described on the basis of light and electron microscope observations ofcultured material originally collected and isolated from seawater of Jiaozhou Bay,Qingdao,China.Theperiplasts on the cell body and flagella are covered by five types of scales,two types on the flagella andthree on the body.Among these,the morphology and the number of spines of large stellate body scalesdiffer remarkably from those of previously described species of Nephroselmis.Apart from these,the unusualfine structure of the eyespot(stigma)is very characteristic.As in the other species of Nephroselmis,theeyespot lies immediately under the two-membraned chloroplast envelope;unlike the others,however,it isnot composed of a number of osmiophilic globules,but consists of about 14 curved rod-shapedosmiophilic bodies arranged loosely and randomly.This feature distinguishes the present new species notonly from the other species of Nephroselmis but also from the other motile algal species,the eyespots展开更多
Asbestos is widely applied in such sectors as manufacturing automobiles, tractors, chemical industrial equipment, and electric equipment. Asbestos fiber is harmful to human health. Therefore, the technology of testing...Asbestos is widely applied in such sectors as manufacturing automobiles, tractors, chemical industrial equipment, and electric equipment. Asbestos fiber is harmful to human health. Therefore, the technology of testing for asbestos in products is especially important. At present, in our country’s national specifications, there is no determination method or specification that is applicable to the asbestos in electronic and electric products. In this article, the components of asbestos in electronic and electric products are identified using the method of combining polarizing microscope with X-ray diffractometer. This method is simple, fast, highly reliable, and suitable to be widely adopted.展开更多
Object To detect the healing between artificial bladder and tissue. Method:Healing between 4 artificial bladder and surrounding tissue was observed by scanning electronic microscope. Result 4 prosthesis all could heal...Object To detect the healing between artificial bladder and tissue. Method:Healing between 4 artificial bladder and surrounding tissue was observed by scanning electronic microscope. Result 4 prosthesis all could heal with tissue,but healing extent was different during different time. Conclusion:This artificial bladder could perform a good connection with tissue and the structure of nylon, surface area of prosthesis, time and infection maybe influenced the healing.展开更多
Ultrafast electron sources, which enable high spatiotemporal resolution in time-resolved electron microscopy and scanning probe microscopy, are receiving increased attention. The most widely used method for achieving ...Ultrafast electron sources, which enable high spatiotemporal resolution in time-resolved electron microscopy and scanning probe microscopy, are receiving increased attention. The most widely used method for achieving ultrafast electron sources involves irradiating metal tips by ultrashort laser pulses, causing electron beam emission via the photoelectric effect [including photon-driven(quantum) or field-driven(classical) emission]. However, the thermionic electrons emission process due to the heating effect of ultrashort lasers, particularly its dynamic aspects, has rarely been addressed in previous studies. In this paper, we improved the signal-to-noise ratio of a two-pulse correlation measurement on the tip electron emission by nearly two orders of magnitude using a delay time modulation method. This allowed us to obtain information on the temperature evolution of hot electrons and phonons in a non-equilibrium state, and to extract characteristic time scales for electron-phonon and phonon-phonon scattering. Our findings indicate that the thermionic electrons emission, unlike the instantaneous photoelectric effect, causes electron emission to lag behind the laser pulse by tens of picoseconds, thus significantly affecting the detection of ultrafast dynamics of samples. Furthermore, such a lagging effect was found to be sensitive to the local structure of the metal tip, offering new insights into the improved design of ultrafast electron sources.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.52125307)the National Key R&D Program of China(Grant No.2021YFB3501500)the support from the New Cornerstone Science Foundation through the XPLORER PRIZE。
文摘Rapid technological advancements drive miniaturization and high energy density in devices,thereby increasing nanoscale thermal management demands and urging development of higher spatial resolution technologies for thermal imaging and transport research.Here,we introduce an approach to measure nanoscale thermal resistance using in situ inelastic scanning transmission electron microscopy.By constructing unidirectional heating flux with controlled temperature gradients and analyzing electron energy-loss/gain signals under optimized acquisition conditions,nanometer-resolution in mapping phonon apparent temperature is achieved.Thus,interfacial thermal resistance is determined by calculating the ratio of interfacial temperature difference to bulk temperature gradient.This methodology enables direct measurement of thermal transport properties for atomic-scale structural features(e.g.,defects and heterointerfaces),resolving critical structure-performance relationships,providing a useful tool for investigating thermal phenomena at the(sub-)nanoscale.
文摘The construction of advanced laboratories for precision instruments, such as electron microscopes, involves unique challenges that are influenced by the specific environmental conditions required for optimal functionality. These include mitigating interference from magnetic fields and vibrations, which are critical for maintaining the precision and accuracy of the instruments used. This study aims to offer enhanced project management strategies and detailed construction solutions that address the environmental and technical needs specific to electron microscopy labs, thereby facilitating effective lab operations and extending the lifecycle of high-end precision instruments. Case studies of existing laboratory constructions, onsite investigations, and comprehensive reviews of the technical and environmental requirements provide the basis for a best practice for constructing sophisticated electron microscopy labs. The approach integrates both pre-construction planning and post-construction adjustments to create optimal operational environments. The findings suggest that successful lab constructions are those that incorporate thorough onsite assessments, strategic location choices, and the use of advanced construction materials and techniques specifically designed to counteract environmental challenges like magnetic and vibration interferences. Actionable guidelines for both planning and executing the construction of electron microscope labs highlighted in this tutorial are intended as an important resource to troubleshoot or upgrade existing lab facilities and to consult in preparation of future lab construction projects.
文摘Changes of calmodulin (CaM) distribution in the embryo sac of rice (Oryza sativa subsp. Japonica) at various stages before and after fertilization have been investigated by using immunogold electron microscopy. Before pollination, both cytoplasm and vacuoles of the egg cell, synergids and central cell were labeled by gold particles. A small amount of gold particles were localized in the nucleus, endoplasmic reticulum, mitochondria and dictyosomes. From pollination to fertilization, CaM amount increased in these cells, especially rich in the starch of amyloplasts. Increase of gold particles in the central cell began about 2 h earlier than that in the egg cell. There was no distinct difference of CaM amount between the degenerated and the persistent synergids. It is interesting to observe an obvious change of CaM distribution form during pollination and fertilization from scattered single particles to clustered particles, and back again to single particles after the fertilization finished. CaM was also localized extracellularly in the embryo sac wall as well as in the wall and intercellular space of nucellus cells. The extracellular CaM also changes in its amount and form after pollination. These results suggest that CaM, either intra- or extra-cellular, may play important roles in fertilization and zygote formation.
基金Project supported by the National Key R&D Program of China (Grant No. 2019YFA0708202)the National Natural Science Foundation of China (Grant Nos. 11974023, 52021006, 61974139, 12074369, and 12104017)+1 种基金the “2011 Program” from the Peking–Tsinghua–IOP Collaborative Innovation Center of Quantum Matterthe Youth Supporting Program of Institute of Semiconductors
文摘To gain further understanding of the luminescence properties of multiquantum wells and the factors affecting them on a microscopic level,cathodoluminescence combined with scanning transmission electron microscopy and spectroscopy was used to measure the luminescence of In_(0.15)Ga_(0.85)N five-period multiquantum wells.The lattice-composition-energy relationship was established with the help of energy-dispersive x-ray spectroscopy,and the bandgaps of In_(0.15)Ga_(0.85)N and GaN in multiple quantum wells were extracted by electron energy loss spectroscopy to understand the features of cathodoluminescence spectra.The luminescence differences between different periods of multiquantum wells and the effects of defects such as composition fluctuation and dislocations on the luminescence of multiple quantum wells were revealed.Our study establishing the direct relationship between the atomic structure of In_(x)Ga_(1-x)N multiquantum wells and photoelectric properties provides useful information for nitride applications.
文摘[Objective]The experiment aimed to explore a new way for observing surface structure of Nostoc sphaeroides Kutzing. [Method] The scanning electron microscope was used to observe the epidermal ultrastructure of wild and cultured Nostoc sphaeroides Kutzing. [ Result] The epidermis of wild and cultured Nostoc sphaeroides Kutzing showed mixture structure of fibril colloid which was reticular arranged. The difference between wild and cultured Nostoc sphaeroides Kutzing was that the outer epidermis of cultured Nostoc sphaeroides Kutzing had trichome distribution but the wild Nostoc sphaeroides Kutzing did not has such distribution. The obsevation results of under smaller than 10 μm by scanning electron microscope was touched thick and showed many folds and distortions. [ Conclusion] The scanning electron microscope was an effective way to study development of Nostoc sphaeroides Kutzing colony and it was worth popularizing.
基金Natural Science Foundation of Hebei Province,Grant/Award Number:F2021203097China Postdoctoral Science Foundation,Grant/Award Numbers:2021M702756,2023T160551National Natural Science Foundation of China,Grant/Award Numbers:51971245,52022088。
文摘Li–CO_(2)/O_(2)batteries,a promising energy storage technology,not only provide ultrahigh discharge capacity but also capture CO_(2)and turn it into renewable energy.Their electrochemical reaction pathways'ambiguity,however,creates a hurdle for their practical application.This study used copper selenide(CuSe)nanosheets as the air cathode medium in an environmental transmission electron microscope to in situ study Li–CO_(2)/O_(2)(mix CO_(2)as well as O_(2)at a volume ratio of 1:1)and Li–O_(2)batteries as well as Li–CO_(2)batteries.Primary discharge reactions take place successively in the Li–CO_(2)/O_(2)–CuSe nanobattery:(I)4Li^(+)+O_(2)+4e^(−)→2Li_(2)O;(II)Li_(2)O+CO_(2)→Li_(2)CO_(3).The charge reaction proceeded via(III)2Li_(2)CO_(3)→4Li^(+)+2CO_(2)+O_(2)+4e^(−).However,Li–O_(2)and Li–CO_(2)nanobatteries showed poor cycling stability,suggesting the difficulty in the direct decomposition of the discharge product.The fluctuations of the Li–CO_(2)/O_(2)battery's electrochemistry were also shown to depend heavily on O_(2).The CuSe‐based Li–CO_(2)/O_(2)battery showed exceptional electrochemical performance.The Li^–CO_(2)/O_(2)battery offered a discharge capacity apex of 15,492 mAh g^(−1) and stable cycling 60 times at 100 mA g^(−1).Our research offers crucial insight into the electrochemical behavior of Li–CO_(2)/O_(2),Li–O_(2),and Li–CO_(2)nanobatteries,which may help the creation of high‐performance Li–CO_(2)/O_(2)batteries for energy storage applications.
文摘[ Objective] The paper was to observe Helicotylenchus digonicus by scanning electron microscope （SEM）. [ Method ] H. digonicus collected from Changxing of Zhejiang Province was observed under scanning electron microscope, and its morphological structure was confmned under optical microscope. [ Resuit]The nematode specimens fixed by glutaraldehyde and osmium tetroxide and prepared by critical point drying were unmodified and unshrinkable with clear mor- phological structure, which could be scanned very well by scanning electron microscope. [ Conclusion ] The study provided reference for study and control of H. digonicus.
文摘[Objective] The research aimed to provide reference for classification of pomegranate cultivars and studies of genetic relationship among pomegranate cultivars.[Method] The electron microscope scanning was used to comparatively observe leaf epidermal structures of 4 pomegranate cultivars.[Result] The upper epidermal structures of 4 pomegranate cultivars were similar and showed reticular structure .However, the differences existed in lower epidermis,such as cell shape,cell size and arrangement mode of cell as well as stomatal density,while the structures of leaf vein in lower epidermis of 4 pomegranate cultivars were similar.[Conclusion] The research provided morphological references for studying heterosis of pomegranate to some extent.
基金Supported by Key Project of Science and Technology in Henan Province(152102110100,152102110036)National Natural Science Foundation of China(U1604110,U1404319,31270727,31600992)+3 种基金Nanhu Scholars Program for Young Scholars of XYNU(2016056)Major Science and Technology Project in Henan Province(121100110200)Students Scientific Research Fund of Xinyang Normal University(2015-DXS-158)Fund of Institute for Conservation and Utilization of Agro-bioresources in Dabie Mountains(2016020)
文摘Chalkiness characters affect not only the grain appearance,milling,eating and cooking qualities but also the grain nutritional quality in rice,thus it is one of the most important traits in rice. It is very important for us to investigate the relation of the chalkiness formation and the development of endosperm structure and starch granule of different rice varieties. Here,we have investigated the chalkiness characters such as chalkiness rate,chalkiness degree and chalkiness area in 15 japonica rice varieties from southern Henan. Furthermore,the endosperm structure and starch granules of rice grain were also observed with scanning electron microscope. The results showed that the 15 japonica varieties have a significantly linear relationship between the chalkiness rate and chalkiness degree. Among the varieties,the biggest difference is the chalkiness rate,the second is the chalkiness area,and the last is the chalkiness degree. Moreover,there is a certain correlation between the distribution of starch granules,the arrangement of endosperm cells and the occurrence of grain chalkiness in the different rice varieties. For the same variety,the starch granules of chalky and non-chalky grains have obvious difference,while the starch granules from the transparent part of chalky rice and non-chalky rice do not have significant difference. The results would provide useful references for the improvement of grain quality in rice.
文摘In this work,an old scanning electron microscope(SEM)is refurbished to enhance its image processing capability.How to digitally sample and process an analog image is also presented.An NI PCI-6259 multiple input/output data acquisition(DAQ)board is used to acquire signals originally being sent to an analog display,and then convert the signals into a digital image.Two output channels are used for raster scan of the horizontal and verticle axes of the image buffer,while one input channel is used to read the brightness signals at various coordinate points.Synchronous method is used to maximize the DAQ speed.Finally,the digitally buffered images are read out to display and saved in a hard drive.The hardware and software designs of this work are explained in great detail,which can serve as a very good example for fast synchronous DAQ,advanced virtual instrument design and structural driver programming with LabVIEW.
基金finically supported by the National Key Research and Development Program of China (Grant No. 2016YFB0100100)Strategic Priority Research Program of Chinese Academy of Sciences (CAS, Grant No. XDA09010101)Ningbo Key Science and Technology Projects "Industrial Application Development of Graphene" (Grant No. 2014S10008)
文摘Lithium-rich layered oxides(LrLOs) deliver extremely high specific capacities and are considered to be promising candidates for electric vehicle and smart grid applications. However, the application of LrLOs needs further understanding of the structural complexity and dynamic evolution of monoclinic and rhombohedral phases, in order to overcome the issues including voltage decay, poor rate capability, initial irreversible capacity loss and etc. The development of aberration correction for the transmission electron microscope and concurrent progress in electron spectroscopy, have fueled rapid progress in the understanding of the mechanism of such issues. New techniques based on the transmission electron microscope are first surveyed, and the applications of these techniques for the study of the structure, migration of transition metal, and the activation of oxygen of LrLOs are then explored in detail, with a particular focus on the mechanism of voltage decay.
文摘Specimens of Mugil soiuy were collected from the coastal waters of Bohai Sea in Tianjin. The gillfilaments were cut with fine scissors and soaked for 24h in a fixative consisting of 2.5% glutaralde-hyde in 0.1 mol lphosporic acid buffer. After three washes in a buffer solution the tissue was fixedin a mixture of 1% osmium tetraoxide at 4℃ for 1h. The tissue was dehydrated in graded ethandethanols and dried. The tissue was examined and photographed with an SEM at an accelerating voltage
基金Project supported by the Shanghai Tech University and the National Natural Science Foundation of China(Grant No.11774039)。
文摘A novel instrument that integrates reflection high energy electron diffraction(RHEED),electron energy loss spectroscopy(EELS),and imaging is designed and simulated.Since it can correlate the structural,elemental,and spatial information of the same surface region via the simultaneously acquired patterns of RHEED,EELS,and energy-filtered electron microscopy,it is named correlative reflection electron microscopy(c-REM).Our simulation demonstrates that the spatial resolution of this c-REM is lower than 50 nm,which meets the requirements for in-situ monitoring the structural and chemical evolution of surface in advanced material.
基金Project supported by the National Natural Science Foundation of China （Grant Nos. 60231010, 60471008, and 60571003） and the National Center for Nanoscience and Technology of China.
文摘The low-energy electron point source （LEEPS） microscope, which creates enlarged projection images with lowenergy field emission electron beams, can be used to observe the projection image of nano-scale samples and to characterize the coherence of the field emission beam. In this paper we report the design and test operation performance of a home-made LEEPS microscope. Multi-walled carbon nanotubes （MWCNTs） synthesized by the CVD method were observed by LEEPS microscope using a conventional tungsten tip, and projection images with the magnification of up to 10^4 was obtained. The resolution of the acquired images is -10 nm. A higher resolution and a larger magnification can be expected when the AC magnetic field inside the equipment is shielded and the vibration of the instrument reduced.
文摘The description and function characterization of a flange-on type low energy electron mi- croscope are given. In this microscope a magnetic beam separator with 10° deflection angle is used in order to facilitate compacting the instrument on a single 10 in. flange. Mean- while some correcting elements in the electron optical system are simplified to reduce the complexities of construction and operation. The sample is set close to ground potential, so that all the electrostatic lenses are easily to float at high voltages. The performance of the microscope in typical low energy electron microscopy, low energy electron diffraction and photoemission electron microscopy modes is demonstrated through several experiments. A lateral resolution of 51 nm is estimated for low energy electron microscopy imaging. With femtosecond laser as light source, the consequent nonlinear photoemission makes this micro-scope also suitable for the observation of optical near field phenomena and a lateral resolution of 110 nm is obtained.
基金supported by the National Key Research and Development Program of China(Grant No.2020YFF0218403)the Basic Scientific Research Operating Fund of NIM(Grant No.AKYZD2007-1)。
文摘The line width(often synonymously used for critical dimension,CD)is a crucial parameter in integrated circuits.To accurately control CD values in manufacturing,a reasonable CD reference material is required to calibrate the corresponding instruments.We develop a new reference material with nominal CDs of 160 nm,80 nm,and 40 nm.The line features are investigated based on the metrological scanning electron microscope which is developed by the National Institute of Metrology(NIM)in China.Also,we propose a new characterization method for the precise measurement of CD values.After filtering and leveling the intensity profiles,the line features are characterized by the combination model of the Gaussian and Lorentz functions.The left and right edges of CD are automatically extracted with the profile decomposition and k-means algorithm.Then the width of the two edges at the half intensity position is regarded as the standard CD value.Finally,the measurement results are evaluated in terms of the sample,instrument,algorithm,and repeatability.The experiments indicate efficiency of the proposed method which can be easily applied in practice to accurately characterize CDs.
文摘Nephroselmis gaoae sp.nov.is described on the basis of light and electron microscope observations ofcultured material originally collected and isolated from seawater of Jiaozhou Bay,Qingdao,China.Theperiplasts on the cell body and flagella are covered by five types of scales,two types on the flagella andthree on the body.Among these,the morphology and the number of spines of large stellate body scalesdiffer remarkably from those of previously described species of Nephroselmis.Apart from these,the unusualfine structure of the eyespot(stigma)is very characteristic.As in the other species of Nephroselmis,theeyespot lies immediately under the two-membraned chloroplast envelope;unlike the others,however,it isnot composed of a number of osmiophilic globules,but consists of about 14 curved rod-shapedosmiophilic bodies arranged loosely and randomly.This feature distinguishes the present new species notonly from the other species of Nephroselmis but also from the other motile algal species,the eyespots
文摘Asbestos is widely applied in such sectors as manufacturing automobiles, tractors, chemical industrial equipment, and electric equipment. Asbestos fiber is harmful to human health. Therefore, the technology of testing for asbestos in products is especially important. At present, in our country’s national specifications, there is no determination method or specification that is applicable to the asbestos in electronic and electric products. In this article, the components of asbestos in electronic and electric products are identified using the method of combining polarizing microscope with X-ray diffractometer. This method is simple, fast, highly reliable, and suitable to be widely adopted.
文摘Object To detect the healing between artificial bladder and tissue. Method:Healing between 4 artificial bladder and surrounding tissue was observed by scanning electronic microscope. Result 4 prosthesis all could heal with tissue,but healing extent was different during different time. Conclusion:This artificial bladder could perform a good connection with tissue and the structure of nylon, surface area of prosthesis, time and infection maybe influenced the healing.
基金supported by the National Key R&D Program under Grant No.2021YFA1400500the National Natural Science Foundation of China under Grant No.22273029+1 种基金the New Cornerstone Science Foundation through the New Cornerstone Investigator Program under Grant No.NCI202303 and the XPLORER PRIZEthe Beijing Outstanding Young Scientist Program under Grant No.JWZQ20240101002。
文摘Ultrafast electron sources, which enable high spatiotemporal resolution in time-resolved electron microscopy and scanning probe microscopy, are receiving increased attention. The most widely used method for achieving ultrafast electron sources involves irradiating metal tips by ultrashort laser pulses, causing electron beam emission via the photoelectric effect [including photon-driven(quantum) or field-driven(classical) emission]. However, the thermionic electrons emission process due to the heating effect of ultrashort lasers, particularly its dynamic aspects, has rarely been addressed in previous studies. In this paper, we improved the signal-to-noise ratio of a two-pulse correlation measurement on the tip electron emission by nearly two orders of magnitude using a delay time modulation method. This allowed us to obtain information on the temperature evolution of hot electrons and phonons in a non-equilibrium state, and to extract characteristic time scales for electron-phonon and phonon-phonon scattering. Our findings indicate that the thermionic electrons emission, unlike the instantaneous photoelectric effect, causes electron emission to lag behind the laser pulse by tens of picoseconds, thus significantly affecting the detection of ultrafast dynamics of samples. Furthermore, such a lagging effect was found to be sensitive to the local structure of the metal tip, offering new insights into the improved design of ultrafast electron sources.
