Precise and reliable presentation of odorants to animals is crucial for olfactory studies.Although odor stimulation systems in anesthetized or awake,head-fixed animals are well established,temporally precise odor prese...Precise and reliable presentation of odorants to animals is crucial for olfactory studies.Although odor stimulation systems in anesthetized or awake,head-fixed animals are well established,temporally precise odor presentation in awake,freely moving animals remains a challenge.Here,we describe a new odor stimulation system which presents odors directly to the nostrils of freely moving mice.The system comprises 3 modules:an odor-delivery module,an odor-generation module,and a control module.The new system is precise and temporally reliable,and odor stimulation can be triggered by specific sniffing phases or other events.Moreover,the system can be combined with neural recordings,such as electrophysiology,and olfactory behavioral tests to investigate how neurons in the brain represent odor information during individual olfactory behaviors.This innovative odor stimulation system may replace traditional stimulation systems:It will enable precise odor presentation in a wide range of olfactory studies in freely moving animals.展开更多
Energy dissipation is one of the most important properties of granular gas, which makes Its behavior dltterent trom that of molecular gas. In this work we report our investigations on the freely-cooling evolution of g...Energy dissipation is one of the most important properties of granular gas, which makes Its behavior dltterent trom that of molecular gas. In this work we report our investigations on the freely-cooling evolution of granular gas under microgravity in a drop tower experiment, and also conduct the molecular dynamics （MD） simulation for comparison. While our experimental and simulation results support Haff＇s law that the kinetic energy dissipates with time t as E（t） （1 ＋ t/v） 2, we modify ~＂ by taking into account the friction dissipation during collisions, and study the effects of number density and particle size on the collision frequency. From the standard deviation of the measured velocity distributions we also verify the energy dissipation law, which is in agreement with Haff＇s kinetic energy dissipation.展开更多
We theoretically design and experimentally realize a broadband ultrasmall microcavity for sensing a varying number of microparticles whose diameter is 2 μm in a freely suspended microfiber. The performance of the mic...We theoretically design and experimentally realize a broadband ultrasmall microcavity for sensing a varying number of microparticles whose diameter is 2 μm in a freely suspended microfiber. The performance of the microcavity is predicted by the theory of one-dimensional photonic crystals and verified by the numerical simulation of finite-difference time domain and the experimental characterization of reflection and transmission spectra. A penetrating length into the reflectors as small as about four periods is demonstrated in the numerical simulation,giving rise to an ultrasmall effective mode volume that can increase the sensitivity and spatial resolution of sensing. Moreover, a reflection band as large as 150 nm from the reflectors of the microcavity has been realized in silica optical microfiber in the experiment, which highly expands the wavelength range of sensing. Our proposed microcavity integrated into a freely suspended optical fiber offers a convenient and stable method for long-distance sensing of microparticles without the need for complicated coupling systems and is free from the influence of substrates.展开更多
Low-density polyethylene(LDPE)has been widely used as a sorbent for passive sampling of hydrophobic organic contaminants(HOCs)in aquatic environments.However,it has seen only limited application in passive sampling fo...Low-density polyethylene(LDPE)has been widely used as a sorbent for passive sampling of hydrophobic organic contaminants(HOCs)in aquatic environments.However,it has seen only limited application in passive sampling for measurement of freely dissolved concentrations of parent and substituted PAHs(SPAHs),which are known to be toxic,mutagenic and carcinogenic.Here,the 16 priority PAHs and some typical PAHs were selected as target compounds and were simultaneously determined by gas chromatography–mass spectrometer(GC–MS).Some batch experiments were conducted in the laboratory to explore the adsorption kinetics of the target compounds in LDPE membranes.The results showed that both PAHs and SPAHs could reach equilibrium status within19–38 days in sorption kinetic experiments.The coefficients of partitioning between LDPE film(50μm thickness)and water(KLDPE)for the 16 priority PAHs were in good agreement with previously reported values,and the values of KLDPEfor the 9 SPAHs are reported in this study for the first time.Significant linear relationships were observed,i.e.,log KLDPE=0.705×log KOW+1.534 for PAHs(R^2=0.8361,p<0.001)and log KLDPE=0.458×log KOW+3.092 for SPAHs(R^2=0.5609,p=0.0077).The selected LDPE film was also proven to meet the condition of"zero sink"for the selected target compounds.These results could provide basic support for the configuration and in situ application of passive samplers.展开更多
The spatial distribution function and second moments of circular freely jointed chain are derived based on an analytical method. The circular Gauss chain, which is simple for long chains, is compared with the circular...The spatial distribution function and second moments of circular freely jointed chain are derived based on an analytical method. The circular Gauss chain, which is simple for long chains, is compared with the circular freely jointed chain, which is exact for short chains. It is shown that the Gauss chain model predicts a more compact configurational distribution than the exact freely jointed chain. The two chain models, however, become closer to each other when the chain length increases. It is found that the difference of the mean square radius of gyration calculated with these two chain models is a constant, independent of the chain length.展开更多
We propose two technologies to extend the number of layers in order to complete the three-dimensional（3D）array diffraction-limited foci, which means there are two-dimensional array foci at multi-focal planes. One te...We propose two technologies to extend the number of layers in order to complete the three-dimensional（3D）array diffraction-limited foci, which means there are two-dimensional array foci at multi-focal planes. One technology is the diffractive optical lever; the other is multi-hybrid Fibonacci structures. Based on the aperiodic Fibonacci structures and binary phase modulation, various kinds of devices can be designed to produce 3D array foci whose focusing properties approximately satisfy the mathematical characteristics of the Fibonacci sequences. With those technologies, the diffraction-limited array foci are freely designed or distributed as required at the desired multiple focal planes.展开更多
For designer,most interior designs of modern times are finished on the settled interface of decoration.Having experiencing so many designs,we can image audaciously why we don't try to change the interior interface...For designer,most interior designs of modern times are finished on the settled interface of decoration.Having experiencing so many designs,we can image audaciously why we don't try to change the interior interface of decoration to that with stronger flexibility after we have tried so many about seeking beauty? Let the interface of decoration divide space freely,which can satisfy the changes of aesthetics.Design can be freely,be changeable,be optional,which,of course,is only my imagination.展开更多
A Lema<span style="white-space:nowrap;">î</span>tre transformation is set up for the free fall in the interior of a stellar object using the frame of the interior Schwarzschild solution...A Lema<span style="white-space:nowrap;">î</span>tre transformation is set up for the free fall in the interior of a stellar object using the frame of the interior Schwarzschild solution. The metric is calculated in comoving coordinates and field strengths are derived for this metric.展开更多
In vito fber photometry is a powerful technique to analyze the dy namics of population neurons during fiunctional study of neuroscience.Here,we introduced a detailed protocol for fiber photometry-based calciun reordin...In vito fber photometry is a powerful technique to analyze the dy namics of population neurons during fiunctional study of neuroscience.Here,we introduced a detailed protocol for fiber photometry-based calciun reording in freely moving mice,covering from virus injection,fiber stub insertion,optogenetical stimulation to data procurement and analysis.Furthemnore,we applied this protocol to explore neuronal activity of mice latenal-posterior(LP)thalaric nucleus in response to optogenetical stimulation of primary visual cortex(V1)neurons,and explore axon clusters activity of optogenetically evoked V1 neurons.Final confirmation of virus-based protein expression in V1 and precise fber insertion indicated that the surgery procedure of this protocol is reliable for functional calcium recording.The scripts for data analysis and some tips in our protocol are provided in details.Together,this protocol is simple,low-cost,and effective for neuronal activity detection by fiber photometry,which will hep neuroscience researchers to carry out fiunctional and behavioral study in vivo.展开更多
Certain molecules such as ethane and acetone possess moiety capable of internal rotation in addition to the rigid structure.When energy is large enough,the methyl group of ethane and acetone can freely rotate along th...Certain molecules such as ethane and acetone possess moiety capable of internal rotation in addition to the rigid structure.When energy is large enough,the methyl group of ethane and acetone can freely rotate along the C—C bond.If not,the methyl group can then only oscillate within certain angles similar to the simple harmonic motion due to the restriction of potential barrier.This is the so-called torsion.展开更多
In the wireless power transfer system for freely moving biomedical implants,the receiving unit was generally inefficient for the reason that its design parameters including the receiving coil's dimension and recei...In the wireless power transfer system for freely moving biomedical implants,the receiving unit was generally inefficient for the reason that its design parameters including the receiving coil's dimension and receiving circuits' topology were always determined by experiments.In order to build the relationship between these parameters and the total transfer efficiency,this paper developed a novel efficiency model based on the impedance model of the coil and the circuit model of the receiving circuits.According to the design constraints,the optimal design parameters in the worst case were derived.The results indicate that the combination of the two-layered receiving coil and half-bridge rectifier has more advantages in size,efficiency and safety,which is preferred in the receiving unit.Additionally,when the load resistance increases,the optimal turn number of the receiving coil basically keeps constant and the corresponding transmitting current and total efficiency decrease.For 100 Ω load,the transmitting current and total efficiency in the worst case were measured to be 5.30 A and 1.45% respectively,which are much better than the published results.In general,our work provides an efficient method to determine the design parameters of the wireless power transfer system for freely moving biomedical implants.展开更多
Ⅰ. INTRODUCTION The selectivity action of zeolite HZSM-5 is greatly enhanced by being modified with certain oxides. Chen, Keading et al. suggested that the pore openings of the zeolite were narrowed by the modificati...Ⅰ. INTRODUCTION The selectivity action of zeolite HZSM-5 is greatly enhanced by being modified with certain oxides. Chen, Keading et al. suggested that the pore openings of the zeolite were narrowed by the modification, and that the m-and o-xylenes were unable to diffuse through them.Since p-xylene alone can pass freely through the openings, selectivity for this isomer is enhanced. Yashima et al. obtained results which indicate that the p-xylene content in the product is related with the acidity of the zeolite.展开更多
Sub-surface crack networks in areas of altered microstructure are a common cause for bearing failures.Due to its appearance under light microscopy,the damage pattern is referred to as White Etching Cracks(WEC).The roo...Sub-surface crack networks in areas of altered microstructure are a common cause for bearing failures.Due to its appearance under light microscopy,the damage pattern is referred to as White Etching Cracks(WEC).The root causes leading to the formation of WEC are still under debate.Nevertheless,it has already been shown that atomic hydrogen can have an accelerating effect on the formation and propagation of WEC.In addition to hydrogen pre-charging,hydrogen can be released and absorbed during rolling/sliding due to the decomposing of the lubricant and water.The current work focuses on the analysis of the hydrogen content of cylindrical roller thrust bearings after testing in a FE8 type test rig using two different lubricants.Within the framework of this work,two different hydrogen analysis methods were used and assessed regarding their applicability.The results show that the so-called Hydrogen Collecting Analysis(HCA)is more suitable to investigate the correlation between lubricant chemistry and hydrogen content in the test bearings than the Local Hydrogen Analysis(LHA).The measurements with the HCA show a continuously increasing freely movable and diffusible hydrogen content under tribological conditions,which leads to the formation of WEC.Comparative tests with an oil without hydrogen showed that the tendency of the system to fail as a result of WEC can be reduced by using a lubricant without hydride compounds.展开更多
基金supported by the National Natural Science Foundation of China(NSFC,31872771 and 32070995 to Anan Li,31872770 to Yufeng Shao)the Jiangsu Province Innovative and Entrepreneurial Team Program.
文摘Precise and reliable presentation of odorants to animals is crucial for olfactory studies.Although odor stimulation systems in anesthetized or awake,head-fixed animals are well established,temporally precise odor presentation in awake,freely moving animals remains a challenge.Here,we describe a new odor stimulation system which presents odors directly to the nostrils of freely moving mice.The system comprises 3 modules:an odor-delivery module,an odor-generation module,and a control module.The new system is precise and temporally reliable,and odor stimulation can be triggered by specific sniffing phases or other events.Moreover,the system can be combined with neural recordings,such as electrophysiology,and olfactory behavioral tests to investigate how neurons in the brain represent odor information during individual olfactory behaviors.This innovative odor stimulation system may replace traditional stimulation systems:It will enable precise odor presentation in a wide range of olfactory studies in freely moving animals.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.U1738120 and 11474326)
文摘Energy dissipation is one of the most important properties of granular gas, which makes Its behavior dltterent trom that of molecular gas. In this work we report our investigations on the freely-cooling evolution of granular gas under microgravity in a drop tower experiment, and also conduct the molecular dynamics （MD） simulation for comparison. While our experimental and simulation results support Haff＇s law that the kinetic energy dissipates with time t as E（t） （1 ＋ t/v） 2, we modify ~＂ by taking into account the friction dissipation during collisions, and study the effects of number density and particle size on the collision frequency. From the standard deviation of the measured velocity distributions we also verify the energy dissipation law, which is in agreement with Haff＇s kinetic energy dissipation.
基金973 Program of China(2013CB632704)National Natural Science Foundation of China(NSFC)(11434017)
文摘We theoretically design and experimentally realize a broadband ultrasmall microcavity for sensing a varying number of microparticles whose diameter is 2 μm in a freely suspended microfiber. The performance of the microcavity is predicted by the theory of one-dimensional photonic crystals and verified by the numerical simulation of finite-difference time domain and the experimental characterization of reflection and transmission spectra. A penetrating length into the reflectors as small as about four periods is demonstrated in the numerical simulation,giving rise to an ultrasmall effective mode volume that can increase the sensitivity and spatial resolution of sensing. Moreover, a reflection band as large as 150 nm from the reflectors of the microcavity has been realized in silica optical microfiber in the experiment, which highly expands the wavelength range of sensing. Our proposed microcavity integrated into a freely suspended optical fiber offers a convenient and stable method for long-distance sensing of microparticles without the need for complicated coupling systems and is free from the influence of substrates.
基金supported by the National Natural Science Foundation of China(Nos.41877471 and 41676095)the China Postdoctoral Science Foundation,China(No.2017M622782)+1 种基金the Open Foundation of Key Laboratory of Tropical Marine Bio-resources and Ecology(LMB),Chinese Academy of Sciences,China(No.LMB20191004)the Science and Technology Innovation Commission of Shenzhen,China(No.JCYJ20180507182227257)
文摘Low-density polyethylene(LDPE)has been widely used as a sorbent for passive sampling of hydrophobic organic contaminants(HOCs)in aquatic environments.However,it has seen only limited application in passive sampling for measurement of freely dissolved concentrations of parent and substituted PAHs(SPAHs),which are known to be toxic,mutagenic and carcinogenic.Here,the 16 priority PAHs and some typical PAHs were selected as target compounds and were simultaneously determined by gas chromatography–mass spectrometer(GC–MS).Some batch experiments were conducted in the laboratory to explore the adsorption kinetics of the target compounds in LDPE membranes.The results showed that both PAHs and SPAHs could reach equilibrium status within19–38 days in sorption kinetic experiments.The coefficients of partitioning between LDPE film(50μm thickness)and water(KLDPE)for the 16 priority PAHs were in good agreement with previously reported values,and the values of KLDPEfor the 9 SPAHs are reported in this study for the first time.Significant linear relationships were observed,i.e.,log KLDPE=0.705×log KOW+1.534 for PAHs(R^2=0.8361,p<0.001)and log KLDPE=0.458×log KOW+3.092 for SPAHs(R^2=0.5609,p=0.0077).The selected LDPE film was also proven to meet the condition of"zero sink"for the selected target compounds.These results could provide basic support for the configuration and in situ application of passive samplers.
文摘The spatial distribution function and second moments of circular freely jointed chain are derived based on an analytical method. The circular Gauss chain, which is simple for long chains, is compared with the circular freely jointed chain, which is exact for short chains. It is shown that the Gauss chain model predicts a more compact configurational distribution than the exact freely jointed chain. The two chain models, however, become closer to each other when the chain length increases. It is found that the difference of the mean square radius of gyration calculated with these two chain models is a constant, independent of the chain length.
基金supported in part by the National Natural Science Foundation of China under Grant Nos.61205212 and 61505228
文摘We propose two technologies to extend the number of layers in order to complete the three-dimensional（3D）array diffraction-limited foci, which means there are two-dimensional array foci at multi-focal planes. One technology is the diffractive optical lever; the other is multi-hybrid Fibonacci structures. Based on the aperiodic Fibonacci structures and binary phase modulation, various kinds of devices can be designed to produce 3D array foci whose focusing properties approximately satisfy the mathematical characteristics of the Fibonacci sequences. With those technologies, the diffraction-limited array foci are freely designed or distributed as required at the desired multiple focal planes.
文摘For designer,most interior designs of modern times are finished on the settled interface of decoration.Having experiencing so many designs,we can image audaciously why we don't try to change the interior interface of decoration to that with stronger flexibility after we have tried so many about seeking beauty? Let the interface of decoration divide space freely,which can satisfy the changes of aesthetics.Design can be freely,be changeable,be optional,which,of course,is only my imagination.
文摘A Lema<span style="white-space:nowrap;">î</span>tre transformation is set up for the free fall in the interior of a stellar object using the frame of the interior Schwarzschild solution. The metric is calculated in comoving coordinates and field strengths are derived for this metric.
基金supported by the National Natural Science Foundation of China (Grant Nos.31371106 and 91632110)HZAU Independent Innovation Fund (2014BQ019).
文摘In vito fber photometry is a powerful technique to analyze the dy namics of population neurons during fiunctional study of neuroscience.Here,we introduced a detailed protocol for fiber photometry-based calciun reording in freely moving mice,covering from virus injection,fiber stub insertion,optogenetical stimulation to data procurement and analysis.Furthemnore,we applied this protocol to explore neuronal activity of mice latenal-posterior(LP)thalaric nucleus in response to optogenetical stimulation of primary visual cortex(V1)neurons,and explore axon clusters activity of optogenetically evoked V1 neurons.Final confirmation of virus-based protein expression in V1 and precise fber insertion indicated that the surgery procedure of this protocol is reliable for functional calcium recording.The scripts for data analysis and some tips in our protocol are provided in details.Together,this protocol is simple,low-cost,and effective for neuronal activity detection by fiber photometry,which will hep neuroscience researchers to carry out fiunctional and behavioral study in vivo.
文摘Certain molecules such as ethane and acetone possess moiety capable of internal rotation in addition to the rigid structure.When energy is large enough,the methyl group of ethane and acetone can freely rotate along the C—C bond.If not,the methyl group can then only oscillate within certain angles similar to the simple harmonic motion due to the restriction of potential barrier.This is the so-called torsion.
基金supported by the National Natural Science Foundation of China(Grant No.61473281)the National Sciences and Technology Support Project(Grant No.2015BAI01B13)State Key Laboratory of Robotics Self-plan Project(Grant No.2016-Z06)
文摘In the wireless power transfer system for freely moving biomedical implants,the receiving unit was generally inefficient for the reason that its design parameters including the receiving coil's dimension and receiving circuits' topology were always determined by experiments.In order to build the relationship between these parameters and the total transfer efficiency,this paper developed a novel efficiency model based on the impedance model of the coil and the circuit model of the receiving circuits.According to the design constraints,the optimal design parameters in the worst case were derived.The results indicate that the combination of the two-layered receiving coil and half-bridge rectifier has more advantages in size,efficiency and safety,which is preferred in the receiving unit.Additionally,when the load resistance increases,the optimal turn number of the receiving coil basically keeps constant and the corresponding transmitting current and total efficiency decrease.For 100 Ω load,the transmitting current and total efficiency in the worst case were measured to be 5.30 A and 1.45% respectively,which are much better than the published results.In general,our work provides an efficient method to determine the design parameters of the wireless power transfer system for freely moving biomedical implants.
文摘Ⅰ. INTRODUCTION The selectivity action of zeolite HZSM-5 is greatly enhanced by being modified with certain oxides. Chen, Keading et al. suggested that the pore openings of the zeolite were narrowed by the modification, and that the m-and o-xylenes were unable to diffuse through them.Since p-xylene alone can pass freely through the openings, selectivity for this isomer is enhanced. Yashima et al. obtained results which indicate that the p-xylene content in the product is related with the acidity of the zeolite.
基金The authors would like to thank the ResearchAssociation for Drive Technology (FVA) for thefunding and support from the research work throughthe research project FVA 707 IV
文摘Sub-surface crack networks in areas of altered microstructure are a common cause for bearing failures.Due to its appearance under light microscopy,the damage pattern is referred to as White Etching Cracks(WEC).The root causes leading to the formation of WEC are still under debate.Nevertheless,it has already been shown that atomic hydrogen can have an accelerating effect on the formation and propagation of WEC.In addition to hydrogen pre-charging,hydrogen can be released and absorbed during rolling/sliding due to the decomposing of the lubricant and water.The current work focuses on the analysis of the hydrogen content of cylindrical roller thrust bearings after testing in a FE8 type test rig using two different lubricants.Within the framework of this work,two different hydrogen analysis methods were used and assessed regarding their applicability.The results show that the so-called Hydrogen Collecting Analysis(HCA)is more suitable to investigate the correlation between lubricant chemistry and hydrogen content in the test bearings than the Local Hydrogen Analysis(LHA).The measurements with the HCA show a continuously increasing freely movable and diffusible hydrogen content under tribological conditions,which leads to the formation of WEC.Comparative tests with an oil without hydrogen showed that the tendency of the system to fail as a result of WEC can be reduced by using a lubricant without hydride compounds.
