Neutral oxygen evolution reaction(OER)is a crucial half-reaction for electrocatalytic chemical production under mild condition,but with limited development due to low activity and poor stability.Herein,a tungsten-dope...Neutral oxygen evolution reaction(OER)is a crucial half-reaction for electrocatalytic chemical production under mild condition,but with limited development due to low activity and poor stability.Herein,a tungsten-doped cobalt molybdate(WDCMO)catalyst was synthesized for efficient and durable OER under neutral electrolyte.It is demonstrated that catalyst reconstruction is suppressed by W doping,which stabilizes the Co-O-Mo point-to-point connection in CoMoO_(4) architecture and stimulates to a lower valence state of active sites over the surface phase.Thereby,the surface structure maintains to avoid compound dissolution caused by over-oxidation during OER.Meanwhile,the WDCMO catalyst promotes charge transfer and optimizes*OH intermediate adsorption,which improves reaction kinetics and intrinsic activity.Consequently,the WDCMO electrode exhibits an overpotential of 302 mV at 10 mA cm^(-2) in neutral electrolyte with an improvement of 182 mV compared with CoMoO4 electrode.Furthermore,W doping significantly improves the electrode stability from 50 h to more than 320 h,with a suppressive potential attenuation from 2.82 to 0.29 mV h^(-1).This work will shed new light on designing rational electrocatalysts for neutral OER.展开更多
Owing to their remarkable flexibility and favorable cost-effectiveness,industrial robots have found extensive applications to cutting of materials across sophisticated manufacturing fields.However,the structurally low...Owing to their remarkable flexibility and favorable cost-effectiveness,industrial robots have found extensive applications to cutting of materials across sophisticated manufacturing fields.However,the structurally low rigidity of these robots renders the tool tip prone to substantial oscillations during machining processes,significantly impacting product fabrication quality.The objective of this study is to present a novel methodology employing magnetorheological dampers for mitigating vibrations during robotic milling operations.Specifically,a new type of ring nested Magneto-Rheological Foam Damper(MRFD)working in the squeeze mode is developed.Firstly,the MRFD’s structure is designed considering the vibrational characteristics of robotic milling.Subsequently,a damping force model of the MRFD is derived.The feasibility of the MRFD’s structural design is validated by the finite element analyses,which is instrumental in comprehending the influence of structural parameters on the electromagnetic characteristics of the MRFD.Next,a prototype of the MRFD is fabricated selecting appropriate parameters.Finally,a series of excitation and milling experiments are conducted on a KUKA KR500 robot.The outcomes demonstrate a substantial reduction(37%-69%)in radial vibration amplitude at the tool tip during robotic milling,highlighting the effectiveness of the developed MRFD.This research endeavor has introduced a pioneering avenue and framework for vibration control in robotic milling,offering a novel paradigm for enhancing the precision of robotic machining.展开更多
In the past 10 years,perovskite solar cells(PSCs)have undergone extremely rapid development,with a record certified power conversion efficiency(PCE)of 26.7%,which is very close to the limit efficiency.However,the inhe...In the past 10 years,perovskite solar cells(PSCs)have undergone extremely rapid development,with a record certified power conversion efficiency(PCE)of 26.7%,which is very close to the limit efficiency.However,the inherent instability caused by ion migration impedes the realization of long-term operationally stable PSCs.In this review,the types and mechanisms of ion migration occurring in various functional layers of negative-intrinsic-positive(n-i-p)PSCs are summarized.Additionally,methods of suppressing ion migration are systematically discussed.Finally,the prospects of current challenges and future development directions are proposed to advance the achievement of high-performance regular PSCs with high stability and PCE.展开更多
Supercapacitors are one of the most promising energy storage devices in the fields of vehicle transportation,flexible electronic devices,aerospace,etc.However,the existed self-discharge that is the spontaneous voltage...Supercapacitors are one of the most promising energy storage devices in the fields of vehicle transportation,flexible electronic devices,aerospace,etc.However,the existed self-discharge that is the spontaneous voltage decay after supercapacitors are fully charged,brings about the wide gap between experimental studies and practical utilization of supercapacitors.Although eliminating the selfdischarge completely is not reachable,suppressing the self-discharge rate to the lowest point is possible and feasible.So far,the significant endeavors have been devoted to achieve this goal.Herein,we summary and discuss the possible mechanisms for the self-discharge and the underlying influence factors.Moreover,the strategies to suppress the self-discharge are systemically summed up by three independent but unified aspects:modifying the electrode,modulating the electrolyte and tuning the separator.Finally,the major challenges to suppress the self-discharge of supercapacitors are concluded and the promising strategies are also pointed out and discussed.This review is presented with the view of serving as a guideline to suppress the self-discharge of supercapacitors and to across-the-board facilitate their widespread application.展开更多
ZnO nanorods are passivated with a TiO2 interracial layer and applied in the CH3NH3PbI3 perovskite solar cell, which prepared by the atomic layer deposition method show a positive effect on the tiff factor and power c...ZnO nanorods are passivated with a TiO2 interracial layer and applied in the CH3NH3PbI3 perovskite solar cell, which prepared by the atomic layer deposition method show a positive effect on the tiff factor and power conversion efficiency. With TiO2 interracial passivation, the charge recombination in the ZnO/CH3NH3PbI3 interface is effectively suppressed and the maximum power conversion efficiency is enhanced from 11.9% to 13.4%.展开更多
Effective multiple optoelectronic feedback circuits for simultaneously suppressing low-frequency and relaxation oscillation intensity noise in a single-frequency phosphate fiber laser are demonstrated. The forward tra...Effective multiple optoelectronic feedback circuits for simultaneously suppressing low-frequency and relaxation oscillation intensity noise in a single-frequency phosphate fiber laser are demonstrated. The forward transfer function, which relates the laser output intensity to the pump modulations, is measured and analyzed. A custom two-path feedback system operating at different frequency bands is designed to adjust the pump current directly. The relative intensity noise is decreased by 20dB from 0.2 to 5kHz and over lOdB from 5 to lOkHz. The relaxation oscillation peak is suppressed by 22dB. In addition, a long term （24h） laser instability of less than 0.05% is achieved.展开更多
Sloshing is a common phenomenon in nature and industry, and it is important in many fields, such as marine engineering and aerospace engineering. To reduce the sloshing load on the side walls, the topology optimizatio...Sloshing is a common phenomenon in nature and industry, and it is important in many fields, such as marine engineering and aerospace engineering. To reduce the sloshing load on the side walls, the topology optimization and optimal control methods are used to design the shape of the board, which is fixed in the middle of the tank. The results show that the new board shape, which is designed via topology optimization, can significantly reduce the sloshing load on the side wall.展开更多
The signal-to-noise ratio （SNR） of seismic reflection data in many areas is rather poor and conventional two-dimensional filters designed to suppress noise with different moveout from the signal tend to generate art...The signal-to-noise ratio （SNR） of seismic reflection data in many areas is rather poor and conventional two-dimensional filters designed to suppress noise with different moveout from the signal tend to generate artifacts. We have extended a method of multichannel filtering, based on the hypothesis that signals on adjacent channels are similar, for enhancing the SNR on stacked sections. Using only the mid-range frequencies where the SNR is highest, the event trend is found for overlapping windows on the section and the average signal vector is calculated. Then the data from the full bandwidth section are projected onto the spatially varying unit similarity vectors and the results are merged for the overlapping windows. Application of the method to synthetic data containing steeply dipping events and to a stacked section for a marine 2D line has produced good results. The modifications we have introduced carry a small overhead in computing time but they should enable the method to be used effectively even on sections containing steep dips.展开更多
Bacground Percutaneous coronary intervention（PCI） has become one of the most effective treatments in coronary heart disease（CHD）.However,the bottleneck problem of PCI is the in-stent restenosis（ISR）.The aim of t...Bacground Percutaneous coronary intervention（PCI） has become one of the most effective treatments in coronary heart disease（CHD）.However,the bottleneck problem of PCI is the in-stent restenosis（ISR）.The aim of this study was to explore the effects of astragaloside IV（AST IV） on suppression of intimal hyperplasia modulation of the expression of basic fibroblast growth factor（b-FGF） in a rat carotid artery balloon injury model.Methods Fifty healthy male Sprague-Dawley（SD）rats were randomly divided into five groups：a sham-operation group（sham）,a model group（model）,and three astragaloside IV-treated groups.Three days before the surgery,1% carboxy methyl cellulose（CMC） or AST IV（20,40 or 60 mg·kg^（- 1）·d^（- 1）） was intragastrically administered into sham or 3 astragaloside-treated groups once a day for 17 days.Hematoxylin-elsin staining was carried out to determine the pathomorphological changes and the neointimal and media area ratio.Immunohistochemistry staining was performed to measure the expressions of proliferating cell nuclear antigen（PCNA）and basic fibrolast growth factor（b-FGF）.PCNA and b-FGF were analyzed with Iamage-Pro Plus.Results（1） The carotid artery intimal hyperplasia in the rats of model was similar to lumen stenosis.Compared with the sham operation group,the area of the new intima and the ratio of the intima to media（I/M） were increased and the lumen area was decreased（P 〈 0.01） in the model group.Astragaloside IV increased the lumen intimal dimension and decreased the area of new intima and the ratio of intima to media in a dose-dependent manner.（2） Compared with the sham-operation group,the expressions of PCNA and b-FGF in carotid artery of model group were significantly increased（P 〈 0.01）.AST IV decreased expressions of PCNA and b-FGF in the carotid artery of rats in a dosedependent manner.Conclusion Astragaloside IV significantly inhibits neointimal hyperplasia of rat carotid artery through down-regulating the expressions of PCNA and b-FGF.展开更多
The pathogenesis of can cer-related in som nia(CRI)mainly in eludes,first,the flow of cancerous toxin leading to the disorder of visceral qi;second,cancer-related radiotherapy and chemotherapy belonging to"exogen...The pathogenesis of can cer-related in som nia(CRI)mainly in eludes,first,the flow of cancerous toxin leading to the disorder of visceral qi;second,cancer-related radiotherapy and chemotherapy belonging to"exogenous pathogenic factors"to a certain extent,which can further aggravate visceral disorders.The therapeutic principle of Chinese medicine is to tranquilize the mind on the basis of regulating viscera,suppressing yang,and astringing yin.On this theoretical basis,Professor Zheng Yuling created a representative prescription of Zhenjing Anshen Granules(镇静安神颗粒)which can achieve the co-regulation of the heart,liver,and kidney,tranquilizing the mind and nourishing the blood.Clinically,the selection of prescriptions and medicines needs to be considered due to factors such as different treatment stages and differ-ences in patients'constitutions.展开更多
The design problem for suppressing 'ground resonance' of the helicopter, with which few researchers have concerned so far, is studied in this paper. Based on the ideas of pole region placement in control theor...The design problem for suppressing 'ground resonance' of the helicopter, with which few researchers have concerned so far, is studied in this paper. Based on the ideas of pole region placement in control theory and of optimization, the method for optimally designing the stiffness and damping parameters of the system with satisfying specified requirements is presented. The effective design criteria and procedures are presented according to the principle of 'ground resonance'.For illustrating the method presented in this paper three typical calculation modes are studied. The results are satisfactory.展开更多
Autoantibodies from patients with various connective tissue diseases have been shown to be specific probes that can detect cellular structures, including centrosome, centromere/kineto- chore, spliceosome, Golgi comple...Autoantibodies from patients with various connective tissue diseases have been shown to be specific probes that can detect cellular structures, including centrosome, centromere/kineto- chore, spliceosome, Golgi complex and the rough endoplasmic reticulum （Louvard et al., 1982; Rattner et al., 1998;展开更多
Current-voltage electrical characteristics of Er silicide/Si（001） nanocontacts are measured in situ in a scanning tunneling microscopy system. Introduced as a new technique to suppress surface leakage conduction on...Current-voltage electrical characteristics of Er silicide/Si（001） nanocontacts are measured in situ in a scanning tunneling microscopy system. Introduced as a new technique to suppress surface leakage conduction on Si（001）,a silver wetting layer is evaporated onto the substrate surface kept at room temperature with Er Si2 nanoislands already existing. The effects of the silver layer on the current-voltage characteristics of nanocontacts are discussed.Our experimental results reveal that the silver layer at coverage of 0.4–0.7 monolayer can suppress effectively the current contribution from the surface conduction path. After the surface leakage path of nanocontacts is obstructed, the ideality factor and the Schottky barrier height are determined using the thermionic emission theory, about 2 and 0.5 eV, respectively. The approach adopted here could shed light on the intrinsic transport properties of metal-semiconductor nanocontacts.展开更多
Non-small cell lung cancer (NSCLC) accounts for 85% of lung cancer, which is the leading cause of death in lung cancer patient. Routine treatment of NSCLC cannot effectively change the survival rate of patients, one i...Non-small cell lung cancer (NSCLC) accounts for 85% of lung cancer, which is the leading cause of death in lung cancer patient. Routine treatment of NSCLC cannot effectively change the survival rate of patients, one important reason is the increased radioresistance of tumor cells after conventional radiotherapy.展开更多
Safety issue of lithium-ion batteries(LIBs)such as fires and explosions is a significant challenge for their large scale applications.Considering the continuously increased battery energy density and wider large-scale...Safety issue of lithium-ion batteries(LIBs)such as fires and explosions is a significant challenge for their large scale applications.Considering the continuously increased battery energy density and wider large-scale battery pack applications,the possibility of LIBs fire significantly increases.Because of the fast burning and the easy re-ignition characteristics of LIBs,achieving an efficient and prompt LIBs fire suppression is critical for minimizing the fire hazards.Different from conventional fire hazards,the LIBs fire shows complicated and comprehensive characteristics,and an effective and suitable fire-extinguishing agent particularly designed for LIBs is highly desirable.Considerable efforts have been devoted to this topic,to the best of our knowledge,a comprehensive review on this regard is still rare.Moreover,in practice,a guidance for the design and selections of a proper fire-extinguishing agent for LIBs is urgently needed.Herein,the special mechanisms and characteristics for LIBs fire and the corresponding design principles for LIBs fire-extinguishing agent were introduced.It is revealed that a fire-extinguishing agent developed for LIBs fire will most likely need a high heat capacity,high wetting,low viscosity and low electrical conductivity.After a comprehensive comparison of these agents in terms of these performances,water-based fire-extinguishing agents show best.Several typical fire-extinguishing agents such as gaseous agents,dry powders,water-based and aerosol fire-extinguishing agents were then introduced,and their fire extinguishment mechanisms were presented.Finally,their effectiveness in suppressing the fire were summarized.Water-based fire-extinguishing agents possess high cooling capacity and excellent anti-reflash performance for the fire.We believe this review could shed light on developing an efficient fire-extinguishing agent particularly designed for LIBs.展开更多
Currently,the effective and clean suppression of lithium-ion battery(LIB)fires remains a challenge.The present work investigates the use of various inhibitor doses(Xin)of dodecafluoro-2-methylpentan-3-one(C_(6) F_(12)...Currently,the effective and clean suppression of lithium-ion battery(LIB)fires remains a challenge.The present work investigates the use of various inhibitor doses(Xin)of dodecafluoro-2-methylpentan-3-one(C_(6) F_(12)O)in 300 Ah LIBs,and systematically examines the thermal and toxic hazards of the extinguished batteries via real scale combustion and gas analysis.The inhibitor is shown to be completely effective.The inhibition mechanism involves a combination of chemical inhibition and physical cooling.While the chemical inhibition effect tends to saturate with increasing Xin,the physical cooling remains effective at higher inhibitor doses.However,extinguishing the battery fire with a high Xin of C_(6)F_(12)O is found to incur serious toxicity problems.These results are expected to provide a guideline for the design of inhibitor doses for the suppression of LIB fires.展开更多
The rolling mill vibration not only seriously causes the strip thickness heterogeneity, but also damages the rolling mill equipment and its electrical components. Existing vibration suppression methods are passive and...The rolling mill vibration not only seriously causes the strip thickness heterogeneity, but also damages the rolling mill equipment and its electrical components. Existing vibration suppression methods are passive and mainly tune mechanical, hydraulic, electrical and rolling process parameters. A new active vibration suppression method was thus proposed using the disturbance estimation and compensation algorithm. Firstly, the hydraulic-mechanical coupling model of the rolling mill vibration was established, and an active vibration suppressor was designed based on the extended state observer. Then, through the numerical simulation, it is found that the vibration energy is reduced by 35.3% using the vibration suppressor, and the vibration suppressor is valid when the vibration frequency is lower than 60 Hz Finally, the vibration suppressor was applied to the in-site manufacturing, and the expected vibration suppression was obtained. The method makes the produced steel strip have more uniform thickness and further significantly increases the finished product ratio.展开更多
In this study,we present three experiments carried out at the EISCAT(European Incoherent Scatter Scientific Association)heating facility on October 29 and 30,2015.The results from the first experiment showed overshoot...In this study,we present three experiments carried out at the EISCAT(European Incoherent Scatter Scientific Association)heating facility on October 29 and 30,2015.The results from the first experiment showed overshoot during the O-mode heating period.The second experiment,which used cold-start X-mode heating,showed the generation of parametric decay instability,whereas overshoot was not observed.The third experiment used power-stepped X-mode heating with noticeable O-mode wave leakage.Parametric decay instability and oscillating two-stream instability were generated at the O-mode reflection height without the overshoot effect,which implies suppression of the thermal parametric instability with X-mode heating.We propose that the electron temperature increased because X-mode heating below the upper hybrid height decreased the growth rate of the thermal parametric instability.展开更多
Pyrolysis of Shenmu coal was performed in fixed-bed reactors indirectly heated by reducing operating pressure and mounting internals in the reactor to explore their synergetic effects on coal pyrolysis. Mounting inter...Pyrolysis of Shenmu coal was performed in fixed-bed reactors indirectly heated by reducing operating pressure and mounting internals in the reactor to explore their synergetic effects on coal pyrolysis. Mounting internals particularly designed greatly improved the heat transfer inside coal bed and raised the yield of tar production.Reducing pressure further facilitated the production of tar through its suppression of secondary reactions occurring in the reactor. The absolute increase in tar yield reached 3.33 wt% in comparison with the pyrolysis in the reactor without internals under atmospheric pressure. The obtained tar yield in the reactor with internals under reduced pressure was even higher than the yield of Gray–King assay. Through experiments in a laboratory fixed bed reactor, it was also clarified that the effect of reducing pressure is related to volatile release rate in pyrolysis. It did not obviously vary tar yield at pyrolysis temperatures below 600 ℃, while the effect was evident at 650 and 700 ℃ but became limited again above 800 ℃. Under reduced pressure the produced tar contained more aliphatics and phenols but less aromatics.展开更多
A combined method of numerical simulation and field testing was adopted in this study in the interest of solving the problem of hard to control high concentrate dusts on a fully mechanized mining face. In addi- tion, ...A combined method of numerical simulation and field testing was adopted in this study in the interest of solving the problem of hard to control high concentrate dusts on a fully mechanized mining face. In addi- tion, the dust suppression effect of a multi-direction whirling air curtain was studied in this paper. Under the influence of the wall attachment effect, the compressed air which blows out from the two-phase or three-phase radial outlets on the generator of the air curtain can form a multi-direction whirling air curtain, which can cover the whole roadway section of a fully mechanized mining face. The traditional method of controlling dust is a forcing system with exhaust overlap which has the major disadvantage of lacking a jet effect and consequently results in poor dust control. It is difficult to form the air flow field within the range of Lp ≤ 5√S. However, due to the effect of this novel system, the radial airflow can be turned into axial airflow allowing fresh air to flow through the length of the heading. The air flow field which is good at controlling dust diffusion can be formed 12.8 m from the heading face. Furthermore, the field measurement results show that before the application of a multi-direction whirling air curtain, the dust concentration is 348.6 mg/m^3 and 271.4 mg/m^3 respectively at the roadway cross-section measurement points which are 5 m and 10 m from the heading face. However, after the application of the multi-direction whirling air curtain, the dust concentration is only 61.2 mg/m3 and 14.8 mg/m^3, respectively. Therefore, the dust control effect of a multi-direction whirling air curtain is obvious.展开更多
文摘Neutral oxygen evolution reaction(OER)is a crucial half-reaction for electrocatalytic chemical production under mild condition,but with limited development due to low activity and poor stability.Herein,a tungsten-doped cobalt molybdate(WDCMO)catalyst was synthesized for efficient and durable OER under neutral electrolyte.It is demonstrated that catalyst reconstruction is suppressed by W doping,which stabilizes the Co-O-Mo point-to-point connection in CoMoO_(4) architecture and stimulates to a lower valence state of active sites over the surface phase.Thereby,the surface structure maintains to avoid compound dissolution caused by over-oxidation during OER.Meanwhile,the WDCMO catalyst promotes charge transfer and optimizes*OH intermediate adsorption,which improves reaction kinetics and intrinsic activity.Consequently,the WDCMO electrode exhibits an overpotential of 302 mV at 10 mA cm^(-2) in neutral electrolyte with an improvement of 182 mV compared with CoMoO4 electrode.Furthermore,W doping significantly improves the electrode stability from 50 h to more than 320 h,with a suppressive potential attenuation from 2.82 to 0.29 mV h^(-1).This work will shed new light on designing rational electrocatalysts for neutral OER.
基金co-supported by the Natural Science Foundation of Jiangsu Province(No.BK20230092)by the National Natural Science Foundation of China(Nos.52375500,52075256,and U22A20204).
文摘Owing to their remarkable flexibility and favorable cost-effectiveness,industrial robots have found extensive applications to cutting of materials across sophisticated manufacturing fields.However,the structurally low rigidity of these robots renders the tool tip prone to substantial oscillations during machining processes,significantly impacting product fabrication quality.The objective of this study is to present a novel methodology employing magnetorheological dampers for mitigating vibrations during robotic milling operations.Specifically,a new type of ring nested Magneto-Rheological Foam Damper(MRFD)working in the squeeze mode is developed.Firstly,the MRFD’s structure is designed considering the vibrational characteristics of robotic milling.Subsequently,a damping force model of the MRFD is derived.The feasibility of the MRFD’s structural design is validated by the finite element analyses,which is instrumental in comprehending the influence of structural parameters on the electromagnetic characteristics of the MRFD.Next,a prototype of the MRFD is fabricated selecting appropriate parameters.Finally,a series of excitation and milling experiments are conducted on a KUKA KR500 robot.The outcomes demonstrate a substantial reduction(37%-69%)in radial vibration amplitude at the tool tip during robotic milling,highlighting the effectiveness of the developed MRFD.This research endeavor has introduced a pioneering avenue and framework for vibration control in robotic milling,offering a novel paradigm for enhancing the precision of robotic machining.
基金financially supported by the National Natural Sci-ence Foundation of China(62274018,52462031)the Xinjiang Construction Corps Key Areas of Science and Technology Research Project(2023AB029)+1 种基金the Tianchi Talent Program of Xinjiang Uygur Autonomous Region(2024,Jiangzhao Chen)the Key Project of Chongqing Overseas Students Returning to China Entrepreneurship and Innovation Support Plan(cx2023006).
文摘In the past 10 years,perovskite solar cells(PSCs)have undergone extremely rapid development,with a record certified power conversion efficiency(PCE)of 26.7%,which is very close to the limit efficiency.However,the inherent instability caused by ion migration impedes the realization of long-term operationally stable PSCs.In this review,the types and mechanisms of ion migration occurring in various functional layers of negative-intrinsic-positive(n-i-p)PSCs are summarized.Additionally,methods of suppressing ion migration are systematically discussed.Finally,the prospects of current challenges and future development directions are proposed to advance the achievement of high-performance regular PSCs with high stability and PCE.
基金partly supported by the National Natural Science Foundation of China(NSFC,No.51872035)the Talent Program of Rejuvenation of the Liaoning(No.XLYC1807002)+1 种基金the Fundamental Research Funds for the Central Universities(DUT19LAB20)the National Key Research Development Program of China(2016YFB0101201)。
文摘Supercapacitors are one of the most promising energy storage devices in the fields of vehicle transportation,flexible electronic devices,aerospace,etc.However,the existed self-discharge that is the spontaneous voltage decay after supercapacitors are fully charged,brings about the wide gap between experimental studies and practical utilization of supercapacitors.Although eliminating the selfdischarge completely is not reachable,suppressing the self-discharge rate to the lowest point is possible and feasible.So far,the significant endeavors have been devoted to achieve this goal.Herein,we summary and discuss the possible mechanisms for the self-discharge and the underlying influence factors.Moreover,the strategies to suppress the self-discharge are systemically summed up by three independent but unified aspects:modifying the electrode,modulating the electrolyte and tuning the separator.Finally,the major challenges to suppress the self-discharge of supercapacitors are concluded and the promising strategies are also pointed out and discussed.This review is presented with the view of serving as a guideline to suppress the self-discharge of supercapacitors and to across-the-board facilitate their widespread application.
基金Supported by the National Key Basic Research Program of China under Grant Nos 2012CB932903 and 2012CB932904the Beijing Science and Technology Committee under Grant No Z131100006013003+1 种基金the National Natural Science Foundation of China under Grant Nos 51372270,51372272,21173260,11474333,91433205,51421002 and 91233202the Knowledge Innovation Program of Chinese Academy of Sciences
文摘ZnO nanorods are passivated with a TiO2 interracial layer and applied in the CH3NH3PbI3 perovskite solar cell, which prepared by the atomic layer deposition method show a positive effect on the tiff factor and power conversion efficiency. With TiO2 interracial passivation, the charge recombination in the ZnO/CH3NH3PbI3 interface is effectively suppressed and the maximum power conversion efficiency is enhanced from 11.9% to 13.4%.
基金Supported by the National High-Technology Research and Development Program of China under Grant Nos 2013AA031502 and 2014AA041902the National Natural Science Foundation of China under Grant Nos 11174085,51132004,and 51302086+3 种基金the Guangdong Natural Science Foundation under Grant Nos S2011030001349 and S20120011380the China National Funds for Distinguished Young Scientists under Grant No 61325024the Science and Technology Project of Guangdong Province under Grant No 2013B090500028the’Cross and Cooperative’Science and Technology Innovation Team Project of Chinese Academy of Sciences under Grant No 2012-119
文摘Effective multiple optoelectronic feedback circuits for simultaneously suppressing low-frequency and relaxation oscillation intensity noise in a single-frequency phosphate fiber laser are demonstrated. The forward transfer function, which relates the laser output intensity to the pump modulations, is measured and analyzed. A custom two-path feedback system operating at different frequency bands is designed to adjust the pump current directly. The relative intensity noise is decreased by 20dB from 0.2 to 5kHz and over lOdB from 5 to lOkHz. The relaxation oscillation peak is suppressed by 22dB. In addition, a long term （24h） laser instability of less than 0.05% is achieved.
基金Project supported by the National Natural Science Foundation of China(Nos.11572350,11372068,and 11602051)the National Key Basic Research and Development Program of China(No.2014CB744104)
文摘Sloshing is a common phenomenon in nature and industry, and it is important in many fields, such as marine engineering and aerospace engineering. To reduce the sloshing load on the side walls, the topology optimization and optimal control methods are used to design the shape of the board, which is fixed in the middle of the tank. The results show that the new board shape, which is designed via topology optimization, can significantly reduce the sloshing load on the side wall.
文摘The signal-to-noise ratio （SNR） of seismic reflection data in many areas is rather poor and conventional two-dimensional filters designed to suppress noise with different moveout from the signal tend to generate artifacts. We have extended a method of multichannel filtering, based on the hypothesis that signals on adjacent channels are similar, for enhancing the SNR on stacked sections. Using only the mid-range frequencies where the SNR is highest, the event trend is found for overlapping windows on the section and the average signal vector is calculated. Then the data from the full bandwidth section are projected onto the spatially varying unit similarity vectors and the results are merged for the overlapping windows. Application of the method to synthetic data containing steeply dipping events and to a stacked section for a marine 2D line has produced good results. The modifications we have introduced carry a small overhead in computing time but they should enable the method to be used effectively even on sections containing steep dips.
基金supported by Natural Scientific Foundation of Shandong Province of China(No.ZR2011HL006)
文摘Bacground Percutaneous coronary intervention（PCI） has become one of the most effective treatments in coronary heart disease（CHD）.However,the bottleneck problem of PCI is the in-stent restenosis（ISR）.The aim of this study was to explore the effects of astragaloside IV（AST IV） on suppression of intimal hyperplasia modulation of the expression of basic fibroblast growth factor（b-FGF） in a rat carotid artery balloon injury model.Methods Fifty healthy male Sprague-Dawley（SD）rats were randomly divided into five groups：a sham-operation group（sham）,a model group（model）,and three astragaloside IV-treated groups.Three days before the surgery,1% carboxy methyl cellulose（CMC） or AST IV（20,40 or 60 mg·kg^（- 1）·d^（- 1）） was intragastrically administered into sham or 3 astragaloside-treated groups once a day for 17 days.Hematoxylin-elsin staining was carried out to determine the pathomorphological changes and the neointimal and media area ratio.Immunohistochemistry staining was performed to measure the expressions of proliferating cell nuclear antigen（PCNA）and basic fibrolast growth factor（b-FGF）.PCNA and b-FGF were analyzed with Iamage-Pro Plus.Results（1） The carotid artery intimal hyperplasia in the rats of model was similar to lumen stenosis.Compared with the sham operation group,the area of the new intima and the ratio of the intima to media（I/M） were increased and the lumen area was decreased（P 〈 0.01） in the model group.Astragaloside IV increased the lumen intimal dimension and decreased the area of new intima and the ratio of intima to media in a dose-dependent manner.（2） Compared with the sham-operation group,the expressions of PCNA and b-FGF in carotid artery of model group were significantly increased（P 〈 0.01）.AST IV decreased expressions of PCNA and b-FGF in the carotid artery of rats in a dosedependent manner.Conclusion Astragaloside IV significantly inhibits neointimal hyperplasia of rat carotid artery through down-regulating the expressions of PCNA and b-FGF.
基金supported by"Hundred-Thousand-Ten Thousand"Talents Project of Chinese Medicine Inheritance and Innovation(Qihuang Project)-Qihuang Scholars(284 Official Letter of People's Education of Chinese Medicine 2018)Special Scientific Research Project of National Clinical Research Base of Traditional Chinese Medicine(2019JDZX001)+2 种基金Special Scientific Research Project of National Clinical Research Base of Chinese Medicine(2019JDZX028)Key Scientific Research Project of Henan Province Colleges and Universities(20A360005)Henan Province Science and Technology Research and Social Development Project(202102310497).
文摘The pathogenesis of can cer-related in som nia(CRI)mainly in eludes,first,the flow of cancerous toxin leading to the disorder of visceral qi;second,cancer-related radiotherapy and chemotherapy belonging to"exogenous pathogenic factors"to a certain extent,which can further aggravate visceral disorders.The therapeutic principle of Chinese medicine is to tranquilize the mind on the basis of regulating viscera,suppressing yang,and astringing yin.On this theoretical basis,Professor Zheng Yuling created a representative prescription of Zhenjing Anshen Granules(镇静安神颗粒)which can achieve the co-regulation of the heart,liver,and kidney,tranquilizing the mind and nourishing the blood.Clinically,the selection of prescriptions and medicines needs to be considered due to factors such as different treatment stages and differ-ences in patients'constitutions.
文摘The design problem for suppressing 'ground resonance' of the helicopter, with which few researchers have concerned so far, is studied in this paper. Based on the ideas of pole region placement in control theory and of optimization, the method for optimally designing the stiffness and damping parameters of the system with satisfying specified requirements is presented. The effective design criteria and procedures are presented according to the principle of 'ground resonance'.For illustrating the method presented in this paper three typical calculation modes are studied. The results are satisfactory.
基金supported by the grants from the Ministry of Science and Technology (No. 2012AA022502 to C.Z.)the National Science Foundation of China (Nos. 81101490 to G.L., 31171371 to D.H.)
文摘Autoantibodies from patients with various connective tissue diseases have been shown to be specific probes that can detect cellular structures, including centrosome, centromere/kineto- chore, spliceosome, Golgi complex and the rough endoplasmic reticulum （Louvard et al., 1982; Rattner et al., 1998;
基金Supported by the National Natural Science Foundation of China under Grant No 11374058
文摘Current-voltage electrical characteristics of Er silicide/Si（001） nanocontacts are measured in situ in a scanning tunneling microscopy system. Introduced as a new technique to suppress surface leakage conduction on Si（001）,a silver wetting layer is evaporated onto the substrate surface kept at room temperature with Er Si2 nanoislands already existing. The effects of the silver layer on the current-voltage characteristics of nanocontacts are discussed.Our experimental results reveal that the silver layer at coverage of 0.4–0.7 monolayer can suppress effectively the current contribution from the surface conduction path. After the surface leakage path of nanocontacts is obstructed, the ideality factor and the Schottky barrier height are determined using the thermionic emission theory, about 2 and 0.5 eV, respectively. The approach adopted here could shed light on the intrinsic transport properties of metal-semiconductor nanocontacts.
基金Key Program of National Natural Science Foundation of China(U1432248)
文摘Non-small cell lung cancer (NSCLC) accounts for 85% of lung cancer, which is the leading cause of death in lung cancer patient. Routine treatment of NSCLC cannot effectively change the survival rate of patients, one important reason is the increased radioresistance of tumor cells after conventional radiotherapy.
基金This work was supported by the National Key Research and Development Program of China(grant number 2017YFC0804700)the National Key Research and Development Program(2019YFC0810703)the National Natural Science Foundation of China(grant number 51874041).
文摘Safety issue of lithium-ion batteries(LIBs)such as fires and explosions is a significant challenge for their large scale applications.Considering the continuously increased battery energy density and wider large-scale battery pack applications,the possibility of LIBs fire significantly increases.Because of the fast burning and the easy re-ignition characteristics of LIBs,achieving an efficient and prompt LIBs fire suppression is critical for minimizing the fire hazards.Different from conventional fire hazards,the LIBs fire shows complicated and comprehensive characteristics,and an effective and suitable fire-extinguishing agent particularly designed for LIBs is highly desirable.Considerable efforts have been devoted to this topic,to the best of our knowledge,a comprehensive review on this regard is still rare.Moreover,in practice,a guidance for the design and selections of a proper fire-extinguishing agent for LIBs is urgently needed.Herein,the special mechanisms and characteristics for LIBs fire and the corresponding design principles for LIBs fire-extinguishing agent were introduced.It is revealed that a fire-extinguishing agent developed for LIBs fire will most likely need a high heat capacity,high wetting,low viscosity and low electrical conductivity.After a comprehensive comparison of these agents in terms of these performances,water-based fire-extinguishing agents show best.Several typical fire-extinguishing agents such as gaseous agents,dry powders,water-based and aerosol fire-extinguishing agents were then introduced,and their fire extinguishment mechanisms were presented.Finally,their effectiveness in suppressing the fire were summarized.Water-based fire-extinguishing agents possess high cooling capacity and excellent anti-reflash performance for the fire.We believe this review could shed light on developing an efficient fire-extinguishing agent particularly designed for LIBs.
基金funded by the Science and Technology Project of the State Grid Corporation of China (Exploration study on Fire Extinguishing Technology of Lithium Ion Energy Storage Battery DG71-18-002)。
文摘Currently,the effective and clean suppression of lithium-ion battery(LIB)fires remains a challenge.The present work investigates the use of various inhibitor doses(Xin)of dodecafluoro-2-methylpentan-3-one(C_(6) F_(12)O)in 300 Ah LIBs,and systematically examines the thermal and toxic hazards of the extinguished batteries via real scale combustion and gas analysis.The inhibitor is shown to be completely effective.The inhibition mechanism involves a combination of chemical inhibition and physical cooling.While the chemical inhibition effect tends to saturate with increasing Xin,the physical cooling remains effective at higher inhibitor doses.However,extinguishing the battery fire with a high Xin of C_(6)F_(12)O is found to incur serious toxicity problems.These results are expected to provide a guideline for the design of inhibitor doses for the suppression of LIB fires.
文摘The rolling mill vibration not only seriously causes the strip thickness heterogeneity, but also damages the rolling mill equipment and its electrical components. Existing vibration suppression methods are passive and mainly tune mechanical, hydraulic, electrical and rolling process parameters. A new active vibration suppression method was thus proposed using the disturbance estimation and compensation algorithm. Firstly, the hydraulic-mechanical coupling model of the rolling mill vibration was established, and an active vibration suppressor was designed based on the extended state observer. Then, through the numerical simulation, it is found that the vibration energy is reduced by 35.3% using the vibration suppressor, and the vibration suppressor is valid when the vibration frequency is lower than 60 Hz Finally, the vibration suppressor was applied to the in-site manufacturing, and the expected vibration suppression was obtained. The method makes the produced steel strip have more uniform thickness and further significantly increases the finished product ratio.
基金EISCAT is an international scientific association supported by research organizations in China(China Research Institute of Radiowave Propagation(CRIRP)),Finland(Suomen Akatemia(SA)),Japan(National Institute of Polar Research(NIPR)and Solar-Terrestrial Environment Laboratory(STEL)),Norway(The Research Council of Norway(NFR)),Sweden(Swedish Research Council(VR)),and the United Kingdom(Natural Environment Research Council(NERC)).This work was supported by the National Natural Science Foundation of China(NSFC,grants 41204111,41574146,41774162,and 41704155)the China Postdoctoral Science Foundation(grant 2017M622504).The experiment described in this work was carried out by the Russian team led by N.F.Blagoveshchenskaya.The data used in this research are available through the EISCAT Madrigal database(http://www.eiscat.se/madrigal/)and EISCAT Dynasonde database(https://dynserv.eiscat.uit.no/).
文摘In this study,we present three experiments carried out at the EISCAT(European Incoherent Scatter Scientific Association)heating facility on October 29 and 30,2015.The results from the first experiment showed overshoot during the O-mode heating period.The second experiment,which used cold-start X-mode heating,showed the generation of parametric decay instability,whereas overshoot was not observed.The third experiment used power-stepped X-mode heating with noticeable O-mode wave leakage.Parametric decay instability and oscillating two-stream instability were generated at the O-mode reflection height without the overshoot effect,which implies suppression of the thermal parametric instability with X-mode heating.We propose that the electron temperature increased because X-mode heating below the upper hybrid height decreased the growth rate of the thermal parametric instability.
基金Supported by the National Natural Science Foundation of China(21376250)National Basic Research Program of China(2014CB744303)the Strategic Priority Research Program of Chinese Academy of Sciences(XDA07010100)
文摘Pyrolysis of Shenmu coal was performed in fixed-bed reactors indirectly heated by reducing operating pressure and mounting internals in the reactor to explore their synergetic effects on coal pyrolysis. Mounting internals particularly designed greatly improved the heat transfer inside coal bed and raised the yield of tar production.Reducing pressure further facilitated the production of tar through its suppression of secondary reactions occurring in the reactor. The absolute increase in tar yield reached 3.33 wt% in comparison with the pyrolysis in the reactor without internals under atmospheric pressure. The obtained tar yield in the reactor with internals under reduced pressure was even higher than the yield of Gray–King assay. Through experiments in a laboratory fixed bed reactor, it was also clarified that the effect of reducing pressure is related to volatile release rate in pyrolysis. It did not obviously vary tar yield at pyrolysis temperatures below 600 ℃, while the effect was evident at 650 and 700 ℃ but became limited again above 800 ℃. Under reduced pressure the produced tar contained more aliphatics and phenols but less aromatics.
基金supported by the Key Program of the Coal Joint Funds of the National Natural Science Foundation of China (No.U1261205)the Youth Program of National Natural Science Foundation of China (No.51404147)+2 种基金the Class General Financial Grant from the China Postdoctoral Science Foundation (No.2015M570601)the Scientific Research Foundation of Shandong University of Science and Technology for Recruited Talents (No.2014RCJJ029)the State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and the Ministry of Science and Technology,Shandong University of Science and Technology (No.MDPC2013ZR02)
文摘A combined method of numerical simulation and field testing was adopted in this study in the interest of solving the problem of hard to control high concentrate dusts on a fully mechanized mining face. In addi- tion, the dust suppression effect of a multi-direction whirling air curtain was studied in this paper. Under the influence of the wall attachment effect, the compressed air which blows out from the two-phase or three-phase radial outlets on the generator of the air curtain can form a multi-direction whirling air curtain, which can cover the whole roadway section of a fully mechanized mining face. The traditional method of controlling dust is a forcing system with exhaust overlap which has the major disadvantage of lacking a jet effect and consequently results in poor dust control. It is difficult to form the air flow field within the range of Lp ≤ 5√S. However, due to the effect of this novel system, the radial airflow can be turned into axial airflow allowing fresh air to flow through the length of the heading. The air flow field which is good at controlling dust diffusion can be formed 12.8 m from the heading face. Furthermore, the field measurement results show that before the application of a multi-direction whirling air curtain, the dust concentration is 348.6 mg/m^3 and 271.4 mg/m^3 respectively at the roadway cross-section measurement points which are 5 m and 10 m from the heading face. However, after the application of the multi-direction whirling air curtain, the dust concentration is only 61.2 mg/m3 and 14.8 mg/m^3, respectively. Therefore, the dust control effect of a multi-direction whirling air curtain is obvious.
