Due to a series of challenges such as low-orbit maintenance of satellites, the air-breathing electric propulsion has got widespread attention. Commonly, the radio frequency ion thruster is favored by low-orbit mission...Due to a series of challenges such as low-orbit maintenance of satellites, the air-breathing electric propulsion has got widespread attention. Commonly, the radio frequency ion thruster is favored by low-orbit missions due to its high specific impulse and efficiency. In this paper, the power transfer efficiency of the radio frequency ion thruster with different gas compositions is studied experimentally, which is obtained by measuring the radio frequency power and current of the antenna coil with and without discharge operation. The results show that increasing the turns of antenna coils can effectively improve the radio frequency power transfer efficiency, which is due to the improvement of Q factor. In pure N_2 discharge,with the increase of radio frequency power, the radio frequency power transfer efficiency first rises rapidly and then exhibits a less steep increasing trend. The radio frequency power transfer efficiency increases with the increase of gas pressure at relatively high power, while declines rapidly at relatively low power. In N_(2)/O_(2) discharge, increasing the N_(2) content at high power can improve the radio frequency power transfer efficiency, but the opposite was observed at low power. In order to give a better understanding of these trends, an analytic solution in limit cases is utilized, and a Langmuir probe was employed to measure the electron density. It is found that the evolution of radio frequency power transfer efficiency can be well explained by the variation of plasma resistance, which is related to the electron density and the effective electron collision frequency.展开更多
Fostering the use of transit has been broadly accepted as an effective way to improve social equity and reduce the externalities caused by transportation. In the great body of transit literature, many have focused on ...Fostering the use of transit has been broadly accepted as an effective way to improve social equity and reduce the externalities caused by transportation. In the great body of transit literature, many have focused on the improvement of transfer efficiency. However, investigation on transit transfer efficiency is still lacking for medium sized cities or suburban areas that have sprawled from city centers. The special features associated with such an urban form lead to unique travel patterns and bus operations. This work develops a process to improve bus transfer efficiency for small conurbations considering their special characteristics. A case study of New York's Capital District is used to illustrate the proposed method. Results show that the transfer waiting time can be remarkably shortened. The proposed method can be widely adapted to other transit systems in small conurbations.展开更多
Water loss rate is crucial in evaluating the efficiency of atmospheric water harvesting(AWH)materials.However,most moisture-absorbing salts and gels have fixed heat transfer rates,limiting the development of high-perf...Water loss rate is crucial in evaluating the efficiency of atmospheric water harvesting(AWH)materials.However,most moisture-absorbing salts and gels have fixed heat transfer rates,limiting the development of high-performance AWH materials.Herein,an anisotropic PEG/CS/MF nanocomposite(APCM)with adjustable thermal transfer efficiency is presented.APCM was synthesized using polyethylene glycol(PEG),melamine foam(MF),and chitosan(CS)solution through a freeze orientation method.The resulting material exhibits a stable oriented laminated structure formed by hydrogen bonding between PEG,CS,and MF.This unique structure imparts excellent mechanical properties.APCM’s large lamellar gaps and pore diameters enable rapid absorption of atmospheric water molecules at low temperatures without leakage(61.79 kg m^(−3)).The compressible nature of APCM allows for efficient heat transfer at high temperatures,and the release of 80%of absorbed water within 15 min.In a proof-of-concept demonstration using a custom-built AWH device,each cubic meter of APCM achieved three AWH cycles within 24 h,producing over 185 kg of water.Therefore,this innovative design offers a promising solution for enhancing the efficiency of AWH,potentially addressing water scarcity issues in various regions.展开更多
The strain transfer behavior of graphene and black phosphorus heterostructure on fexible substrates plays a crucial role in the functionality and regulation of the device.Specifically,it is imperative to investigate t...The strain transfer behavior of graphene and black phosphorus heterostructure on fexible substrates plays a crucial role in the functionality and regulation of the device.Specifically,it is imperative to investigate the anisotropy associated with strain transfer at the black phosphorus interface.In this study,a sample transfer method was proposed to prevent the contact of black phosphorus with water,achieving monolayer graphene and few-layer black phosphorus heterostructures on a PET flm substrate.Micro-Raman spectroscopy was used to measure the strain of graphene and black phosphorus when the PET flm substrate was under uniaxial tensile loading along the zigzag and armchair directions of black phosphorus,respectively.The Raman shift-strain relationship of black phosphorus was derived,and an interface transfer model was developed for the heterostructure.Based on the model,the strain transfer efficiency of each measuring spot was calculated and the strain transfer mechanism of each layer was analyzed.The results uncover the influence of the anisotropic interlayer properties inside the black phosphorus on the strain transfer behavior in the heterostructure on the flexible substrate.展开更多
The charge transfer efficiency improvement method is introduced by optimizing the electrical potential distribution under the transfer gate along the charge transfer path. A non-uniform doped transfer transistor chan-...The charge transfer efficiency improvement method is introduced by optimizing the electrical potential distribution under the transfer gate along the charge transfer path. A non-uniform doped transfer transistor chan- nel is introduced to provide an ascending electrical potential gradient in the transfer transistor channel. With the adjustments to the overlap length between the R1 region and the transfer gate, the doping dose of the R1 region, and the overlap length between the anti-punch-through （APT） implantations and transfer gate, the potential barrier and potential pocket in the connecting region of transfer transistor channel and the pinned photodiode （PPD） are reduced to improve the electrical potential connection. The simulation results show that the percentage of residual charges to total charges drops from 1/10^4 to 1/10^7, and the transfer time is reduced from 500 to 110 ns. This means the charge transfer efficiency is improved.展开更多
A novel CMOS image sensor(CIS) pinned photodiode(PPD) pixel, named as O-T pixel, is proposed and investigated by TCAD simulations. Compared with the conventional PPD pixel, the proposed pixel features the overlapping ...A novel CMOS image sensor(CIS) pinned photodiode(PPD) pixel, named as O-T pixel, is proposed and investigated by TCAD simulations. Compared with the conventional PPD pixel, the proposed pixel features the overlapping gate(OG)and the temporary storage diffusing(TSD) region, based on which the several-nanosecond-level charge transfer could be achieved and the complete charge transfer from the PPD to the floating node(FD) could be realized. And systematic analyses of the influence of the doping conditions of the proposed processes, the OG length, and the photodiode length on the transfer performances of the proposed pixel are conducted. Optimized simulation results show that the total charge transfer time could reach about 5.862 ns from the photodiode to the sensed node and the corresponding charge transfer efficiency could reach as high as 99.995% in the proposed pixel with 10 μm long photodiode and 2.22 μm long OG. These results demonstrate a great potential of the proposed pixel in high-speed applications.展开更多
In mammalians, the state of a somatic cell can be reversed from the terminal state to the totipotent state by means of somatic cell nuclear transfer （SCNT） （Gurdon, 1962） or induced pluripotent stem cells （iPSCs...In mammalians, the state of a somatic cell can be reversed from the terminal state to the totipotent state by means of somatic cell nuclear transfer （SCNT） （Gurdon, 1962） or induced pluripotent stem cells （iPSCs） （Takahashi and Yamanaka, 2006）. The DNA methylation and transcriptome profiles of embryonic stern cells （ESCs） derived from SCNT embryos （NT-ESCs） correspond closely to those of ESCs derived from in vitro fertilization embryos （IVF- ESCs）. In contrast, iPSCs differ from both NT-ESCs and IVF-ESCs in that they retain the residual DNA methylation patterns of their parental somatic cells. As SCNT can be used to faithfully reprogram human somatic cells to pluripotency, it is ideal for cell replacement therapies （Ma et al., 2014）. Following the successful production of the first human NT-ESCs （Tachibana et al., 2013） and the later gen- eration of human NT-ESCs based on cells from elderly adults or pa- tient cells （Chung et al., 2014; Yamada et al., 2014）, a version of the SCNT technique for human therapeutics comes closer to reality. However, no matter what animal species or donor cell types are used in the cloned process, the cloning efficiency remains undesir- able. Besides, there are many phenotypic abnormalities in cloned animals, containing frequent embryonic and perinatal death and placentomegaly, and the underlying mechanisms remain unclear （Yang et al, 2007）.展开更多
Constructed wetlands(CWs) are a promising method to treat effluent from wastewater treatment plants(WWTPs),However,low carbon/nitrogen(C/N) ratios of the influent inhibit denitrification in CWs,resulting in poor nitro...Constructed wetlands(CWs) are a promising method to treat effluent from wastewater treatment plants(WWTPs),However,low carbon/nitrogen(C/N) ratios of the influent inhibit denitrification in CWs,resulting in poor nitrogen removal efficiency.Herein,we compared traditional(control),biochar(BC), andβ-cyclodextrin-fu nctionalized biochar(BC@β-CD) CW systems to investigate nitrogen removal from influent with low C/N ratios,and the mechanisms that enhance this process.The highest nitrogen removal rates were observed in the BC@β-CD group,with rates 45.89% and 42.48% higher than those of the control,accompanied by a 70.57% and 85.45% decrease in nitrous oxide release,when the C/N ratio decreased from4 to 2,respectively.Metagenomic and enzymatic analyses indicated that BC@β-CD enhances nitrogen removal by coordinately promoting carbon metabolism and increasing denitrification enzyme activities,without affecting microbial species diversity in CWs.Structural equation modeling confirmed that the foremost advantages of BC@β-CD were effective electron generation and transportation resulting from increased activities of nicotinamide adenine dinucleotide(NADH) dehydrogenase and the electron transfer system(ETS),thereby strategically reallocating more carbon metabolic flow to support denitrification.Our results show that the application of BC@β-CD in CWs to optimize the reallocation of electrons from carbon metabolism is a feasible strategy to enhance denitrification under low C/N conditions.展开更多
Nanopowder of Cr：GGG and nanopowder of Cr,Nd：GGG with different concentrations of Cr3＋ ranging from 0.1 at.% to 1.5 at.% were synthesized by the sol-gel method using acetic acid and ethylene glycol. Thermal gravime...Nanopowder of Cr：GGG and nanopowder of Cr,Nd：GGG with different concentrations of Cr3＋ ranging from 0.1 at.% to 1.5 at.% were synthesized by the sol-gel method using acetic acid and ethylene glycol. Thermal gravimetric analysis and differential scanning calorimetry （TGA-DSC）, X-ray diffraction （XRD） and photoluminescence spectroscopy were used to characterize the powder. The crystallite size was about 58 nm when treated at 1000 oC for 2 h. Cr3＋ photoluminescence spectrum in GGG showed a broad band emission around 730 nm. The intensity of this band decreased when co-doped with Nd, indicating an efficient energy transfer from Cr3＋ to Nd3＋. Photoluminescence intensity of Nd in Cr,Nd：GGG at 1.06μm showed that the optimum concentration of Cr3＋ was about 1 at.% （more or less） for 1 at.% Nd3＋. This result was also confirmed by chromium fluorescence decay rate analysis. Energy transfer efficiency was found to be about 84% for 1 at.% concentration of each chromium and neodymium.展开更多
Electron donors(EDs)are widely used to improve the H 2 production performance of Schottky junction photocatalysts,but the functions of EDs are still unknown from the perspective of electron transfer dy-namics.Herein,P...Electron donors(EDs)are widely used to improve the H 2 production performance of Schottky junction photocatalysts,but the functions of EDs are still unknown from the perspective of electron transfer dy-namics.Herein,Pt nanocluster-decorated CdS nanorod is successfully prepared to construct a typical CdS/Pt Schottky junction.Pt nanoclusters with a diameter of∼2 nm are deposited on the surface of CdS nanorods by in situ photoreduction at sub-zero temperature.The CdS/Pt photocatalyst using lactic acid shows a higher H_(2)production rate of 4762μmol g^(-1)h^(-1)compared to that using methanol,tri-ethanolamine,and glycerol.To understand the cause,the dynamics of photogenerated carriers in CdS/Pt photocatalysts during ED-assisted H_(2)production are revealed by femtosecond transient absorption spec-troscopy.Among the four organic EDs,lactic acid enables the fastest electron transfer rate of 1.8×10^(9)s^(-1)and the highest electron transfer efficiency of 76%at the CdS/Pt interface due to the most efficient hole consumption.This work sheds light on the importance of efficient interfacial electron transfer for im-proving the photocatalytic performance of Schottky junction photocatalysts.展开更多
In this paper, we use a nonlinear decohering quantum model to study the initial step of photosynthesis which is an ultrafast transfer process of absorption the sunlight by light-harvesting complexes and electronic exc...In this paper, we use a nonlinear decohering quantum model to study the initial step of photosynthesis which is an ultrafast transfer process of absorption the sunlight by light-harvesting complexes and electronic excitation transfer to the reaction center(RC). In this decohering model, the Hamiltonian of the system commutes with the systemenvironment interaction. We take B850 ring of light-harvesting complex II(LH-II) in purple bacteria as an example to calculate the efficiency of the energy transfer as a function of time. We find that the environmental noise can make the LH-II have stable energy transfer efficiency over a long time. This is to say that the environmental noise which is the decohering source has advantage of the energy transfer in the process of photosynthesis.展开更多
Wide-temperature applications of sodium-ion batteries(SIBs)are severely limited by the sluggish ion insertion/diffusion kinetics of conversion-type anodes.Quantum-sized transition metal dichalcogenides possess unique ...Wide-temperature applications of sodium-ion batteries(SIBs)are severely limited by the sluggish ion insertion/diffusion kinetics of conversion-type anodes.Quantum-sized transition metal dichalcogenides possess unique advantages of charge delocalization and enrich uncoordinated electrons and short-range transfer kinetics,which are crucial to achieve rapid low-temperature charge transfer and high-temperature interface stability.Herein,a quantum-scale FeS_(2) loaded on three-dimensional Ti_(3)C_(2) MXene skeletons(FeS_(2) QD/MXene)fabricated as SIBs anode,demonstrating impressive performance under wide-temperature conditions(−35 to 65).The theoretical calculations combined with experimental characterization interprets that the unsaturated coordination edges of FeS_(2) QD can induce delocalized electronic regions,which reduces electrostatic potential and significantly facilitates efficient Na+diffusion across a broad temperature range.Moreover,the Ti_(3)C_(2) skeleton reinforces structural integrity via Fe-O-Ti bonding,while enabling excellent dispersion of FeS_(2) QD.As expected,FeS_(2) QD/MXene anode harvests capacities of 255.2 and 424.9 mAh g^(−1) at 0.1 A g^(−1) under−35 and 65,and the energy density of FeS_(2) QD/MXene//NVP full cell can reach to 162.4 Wh kg^(−1) at−35,highlighting its practical potential for wide-temperatures conditions.This work extends the uncoordinated regions induced by quantum-size effects for exceptional Na^(+)ion storage and diffusion performance at wide-temperatures environment.展开更多
A 1-dodecanethiol-based phase-transfer protocol is developed for the extraction of noble metal ions from aqueous solution to a hydrocarbon phase, which calls for first mixing the aqueous metal ion solution with an eth...A 1-dodecanethiol-based phase-transfer protocol is developed for the extraction of noble metal ions from aqueous solution to a hydrocarbon phase, which calls for first mixing the aqueous metal ion solution with an ethanolic solution of 1-dodecanethiol, and then extracting the coordination compounds formed between noble metal ions and 1-dodecanethiol into a non-polar organic solvent. A number of characterization techniques, including inductively coupled plasma atomic emission spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis demonstrate that this protocol could be applied to extract a wide variety of noble metal ions from water to dichlorometh- ane with an efficiency of 〉96%, and has high selectivity for the separation of the noble metal ions from other transition metals. It is therefore an attractive alternative for the extraction of noble metals from water, soil, or waste printed circuit boards.展开更多
Fabrication of efficient solid luminogens with tunable emission is both fundamentally significant and technically important. Herein, based on our previous strategy for the construction of efficient and multifunctional...Fabrication of efficient solid luminogens with tunable emission is both fundamentally significant and technically important. Herein, based on our previous strategy for the construction of efficient and multifunctional solid luminogens through the combination of diverse aggregation-induced emission （ALE） units with other functional moieties, a group of luminophores with electron donor-acceptor （D-A） structure and typical intramolecular charge transfer （ICT） characteristics, namely CZ-DCDPP, DPA-DCDPP and DBPA-DCDPP were synthesized and investigated. The presence of twisting and AlE-active 2,3- dicyano-S,6-diphenylpyrazine （DCDPP） moiety endows them highly emissive in the solid states, whereas the introduction of arylamines with varied electron-donating capacity and different conjugation render them with tunable solid emissions from green to red. While CZ-DCDPP and DPA-DCDPP solids exhibit distinct mechanochromism, both DPA-DCDPP and DBPA-DCDPP solids can generate efficient red emission. Owing to their high efficiency, remarkable thermal and morphological stabilities and moreover red emission, they are promising for diverse optoelectronic and biological applications.展开更多
The flux-variance similarity relation and the vertical transfer of scalars exhibit dissimilarity over different types of surfaces, resulting in different parameterization approaches of relative transport efficiency am...The flux-variance similarity relation and the vertical transfer of scalars exhibit dissimilarity over different types of surfaces, resulting in different parameterization approaches of relative transport efficiency among scalars to estimate turbulent fluxes using the flux-variance method. We investigated these issues using eddycovariance measurements over an open, homogeneous and flat grassland in the eastern Tibetan Plateau in summer under intermediate hydrological conditions during rainy season. In unstable conditions, the temperature, water vapor, and CO2 followed the flux-variance similarity relation, but did not show in precisely the same way due to different roles （active or passive） of these scalars. Similarity constants of temperature, water vapor and CO2 were found to be 1.12, 1.19 and 1.17, respectively. Heat transportation was more eft% cient than water vapor and CO2. Based on the estimated sensible heat flux, five parameterization methods of relative transport efficiency of heat to water vapor and CO2 were examined to estimate latent heat and CO2 fluxes. The strategy of local determination of flux-variance similarity relation is recommended for the estimation of latent heat and CO2 fluxes. This approach is better for representing the averaged relative transport efficiency, and technically easier to apply, compared to other more complex ones.展开更多
The novel SiC foam valve tray was made of thin slices of SiC foam material with a high specific surfacearea. Hydrodynamic performances of the novel SiC foam valve tray were studied with air-water system at atmos-pheri...The novel SiC foam valve tray was made of thin slices of SiC foam material with a high specific surfacearea. Hydrodynamic performances of the novel SiC foam valve tray were studied with air-water system at atmos-pheric pressure. These performance parameters included pressure drop, entrainment, weeping and clear liquidheight. The mass transfer efficiency of the SiC foam valve tray was measured in laboratory plate column. Comparedwith the F1 float valve tray, the dry pressure drop was decreased about 25%, the entrainment rate was about 70%lower at high gas load, the weeping was much better, and the mass transfer efficiency was far higher. Thus, theoverall performance of the novel SiC foam valve tray was better than that of F1 float valve tray.展开更多
Solvent extraction phenol from coal tar were carried out with novel composite YH-3 as extraction agent, and the high flux centrifugal extractor was used as extraction device. Under the premise of high phenol extractio...Solvent extraction phenol from coal tar were carried out with novel composite YH-3 as extraction agent, and the high flux centrifugal extractor was used as extraction device. Under the premise of high phenol extraction rate, composite YH-3 extraction agent reduces n-n interaction between phenolic compounds and aromatic hydrocarbons, thus decreasing the entrainment of neutral oil. The optimization of operation conditions, such as the diameter of heavy phase weir HWD, the flow ratio, the total flow rate and the rotation speed, are necessary. For single stage extraction experiment, the mass transfer efficiency was up to 84% while the rate of extraction agent loss was lower than 0.28% with the operation conditions of 29 mm of the heavy phase weir diameter （HWD）, 1：1-1.4：1 of the flow ratio range, 160-200 mL/min of the total flow rate and the rotation speed varied from 2200 to 2600 r/min. For three stage counter-current test, the mass transfer efficiency reached up to 92.6% with the optimum operation condition of 29 mm of the HWD, 1：1 of the flow ratio, 200 rnL/min of the total flow rate and 2400 r/rain of the rotation speed. The results indicated that phenol could be extracted effectively from coal tar in the process of multistage continuous count current centrifugal extraction.展开更多
The vortex formed around the rolling ball and the high pressure region formed around the ball-raceway contact zone are the principle factors that barricades the lubricant entering the bearing cavity, and further cause...The vortex formed around the rolling ball and the high pressure region formed around the ball-raceway contact zone are the principle factors that barricades the lubricant entering the bearing cavity, and further causes improper lubrication. The investigation of the air phase flow inside the bearing cavity is essential for the optimization of the oil-air two-phase lubrication method. With the revolutionary reference frame describing the bearing motion, a highly precise air phase flow model inside the angular contact ball bearing cavity was build up. Comprehensive factors such as bearing revolution, ball rotation, and cage structure were considered to investigate the influences on the air phase flow and heat transfer efficiency. The aerodynamic noise was also analyzed. The result shows that the ball spinning leads to the pressure rise and uneven pressure distribution. The air phase velocity, pressure and cage heat transfer efficiency increase as the revolving speed increases. The operating noise is largely due to the impact of the high speed external flow on the bearing. When the center of the oil-air outlet fixes near the inner ring, the aerodynamic noise is reduced. The position near the inner ring on the bigger axial side is the ideal position to fix the lubricating device for the angular contact ball bearing.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12005031 and 12275041)the Natural Science Fund from the Interdisciplinary Project of Dalian University(Grant No.DLUXK-2023-QN-001)。
文摘Due to a series of challenges such as low-orbit maintenance of satellites, the air-breathing electric propulsion has got widespread attention. Commonly, the radio frequency ion thruster is favored by low-orbit missions due to its high specific impulse and efficiency. In this paper, the power transfer efficiency of the radio frequency ion thruster with different gas compositions is studied experimentally, which is obtained by measuring the radio frequency power and current of the antenna coil with and without discharge operation. The results show that increasing the turns of antenna coils can effectively improve the radio frequency power transfer efficiency, which is due to the improvement of Q factor. In pure N_2 discharge,with the increase of radio frequency power, the radio frequency power transfer efficiency first rises rapidly and then exhibits a less steep increasing trend. The radio frequency power transfer efficiency increases with the increase of gas pressure at relatively high power, while declines rapidly at relatively low power. In N_(2)/O_(2) discharge, increasing the N_(2) content at high power can improve the radio frequency power transfer efficiency, but the opposite was observed at low power. In order to give a better understanding of these trends, an analytic solution in limit cases is utilized, and a Langmuir probe was employed to measure the electron density. It is found that the evolution of radio frequency power transfer efficiency can be well explained by the variation of plasma resistance, which is related to the electron density and the effective electron collision frequency.
文摘Fostering the use of transit has been broadly accepted as an effective way to improve social equity and reduce the externalities caused by transportation. In the great body of transit literature, many have focused on the improvement of transfer efficiency. However, investigation on transit transfer efficiency is still lacking for medium sized cities or suburban areas that have sprawled from city centers. The special features associated with such an urban form lead to unique travel patterns and bus operations. This work develops a process to improve bus transfer efficiency for small conurbations considering their special characteristics. A case study of New York's Capital District is used to illustrate the proposed method. Results show that the transfer waiting time can be remarkably shortened. The proposed method can be widely adapted to other transit systems in small conurbations.
基金Colleges and Universities Science Foundation of Anhui Province (2022AH050908)Anhui Agricultural University Introduction of High-level Talent Funds(RC362202)+1 种基金University Synergy Innovation Program of Anhui Province(GXXT-2023-037)Anhui Province Rural Revitalization Collaborative Technology Service Center Construction Project。
文摘Water loss rate is crucial in evaluating the efficiency of atmospheric water harvesting(AWH)materials.However,most moisture-absorbing salts and gels have fixed heat transfer rates,limiting the development of high-performance AWH materials.Herein,an anisotropic PEG/CS/MF nanocomposite(APCM)with adjustable thermal transfer efficiency is presented.APCM was synthesized using polyethylene glycol(PEG),melamine foam(MF),and chitosan(CS)solution through a freeze orientation method.The resulting material exhibits a stable oriented laminated structure formed by hydrogen bonding between PEG,CS,and MF.This unique structure imparts excellent mechanical properties.APCM’s large lamellar gaps and pore diameters enable rapid absorption of atmospheric water molecules at low temperatures without leakage(61.79 kg m^(−3)).The compressible nature of APCM allows for efficient heat transfer at high temperatures,and the release of 80%of absorbed water within 15 min.In a proof-of-concept demonstration using a custom-built AWH device,each cubic meter of APCM achieved three AWH cycles within 24 h,producing over 185 kg of water.Therefore,this innovative design offers a promising solution for enhancing the efficiency of AWH,potentially addressing water scarcity issues in various regions.
基金supported by the National Natural Science Foundation of China(Grant Nos.12125203,12021002,and 12041201).
文摘The strain transfer behavior of graphene and black phosphorus heterostructure on fexible substrates plays a crucial role in the functionality and regulation of the device.Specifically,it is imperative to investigate the anisotropy associated with strain transfer at the black phosphorus interface.In this study,a sample transfer method was proposed to prevent the contact of black phosphorus with water,achieving monolayer graphene and few-layer black phosphorus heterostructures on a PET flm substrate.Micro-Raman spectroscopy was used to measure the strain of graphene and black phosphorus when the PET flm substrate was under uniaxial tensile loading along the zigzag and armchair directions of black phosphorus,respectively.The Raman shift-strain relationship of black phosphorus was derived,and an interface transfer model was developed for the heterostructure.Based on the model,the strain transfer efficiency of each measuring spot was calculated and the strain transfer mechanism of each layer was analyzed.The results uncover the influence of the anisotropic interlayer properties inside the black phosphorus on the strain transfer behavior in the heterostructure on the flexible substrate.
基金Project supported by National Natural Science Foundation of China(Nos.61036004,61076024)
文摘The charge transfer efficiency improvement method is introduced by optimizing the electrical potential distribution under the transfer gate along the charge transfer path. A non-uniform doped transfer transistor chan- nel is introduced to provide an ascending electrical potential gradient in the transfer transistor channel. With the adjustments to the overlap length between the R1 region and the transfer gate, the doping dose of the R1 region, and the overlap length between the anti-punch-through （APT） implantations and transfer gate, the potential barrier and potential pocket in the connecting region of transfer transistor channel and the pinned photodiode （PPD） are reduced to improve the electrical potential connection. The simulation results show that the percentage of residual charges to total charges drops from 1/10^4 to 1/10^7, and the transfer time is reduced from 500 to 110 ns. This means the charge transfer efficiency is improved.
基金Project supported by the National Natural Science Foundation of China(Grant No.61574112)。
文摘A novel CMOS image sensor(CIS) pinned photodiode(PPD) pixel, named as O-T pixel, is proposed and investigated by TCAD simulations. Compared with the conventional PPD pixel, the proposed pixel features the overlapping gate(OG)and the temporary storage diffusing(TSD) region, based on which the several-nanosecond-level charge transfer could be achieved and the complete charge transfer from the PPD to the floating node(FD) could be realized. And systematic analyses of the influence of the doping conditions of the proposed processes, the OG length, and the photodiode length on the transfer performances of the proposed pixel are conducted. Optimized simulation results show that the total charge transfer time could reach about 5.862 ns from the photodiode to the sensed node and the corresponding charge transfer efficiency could reach as high as 99.995% in the proposed pixel with 10 μm long photodiode and 2.22 μm long OG. These results demonstrate a great potential of the proposed pixel in high-speed applications.
基金supported by grants from the National Natural Science Foundation of China(No.31471395)to Q.Z.the Key Research Projects of the Frontier Science of the Chinese Academy of Sciences(QYZDY-SSW-SMC002)to Q.Z
文摘In mammalians, the state of a somatic cell can be reversed from the terminal state to the totipotent state by means of somatic cell nuclear transfer （SCNT） （Gurdon, 1962） or induced pluripotent stem cells （iPSCs） （Takahashi and Yamanaka, 2006）. The DNA methylation and transcriptome profiles of embryonic stern cells （ESCs） derived from SCNT embryos （NT-ESCs） correspond closely to those of ESCs derived from in vitro fertilization embryos （IVF- ESCs）. In contrast, iPSCs differ from both NT-ESCs and IVF-ESCs in that they retain the residual DNA methylation patterns of their parental somatic cells. As SCNT can be used to faithfully reprogram human somatic cells to pluripotency, it is ideal for cell replacement therapies （Ma et al., 2014）. Following the successful production of the first human NT-ESCs （Tachibana et al., 2013） and the later gen- eration of human NT-ESCs based on cells from elderly adults or pa- tient cells （Chung et al., 2014; Yamada et al., 2014）, a version of the SCNT technique for human therapeutics comes closer to reality. However, no matter what animal species or donor cell types are used in the cloned process, the cloning efficiency remains undesir- able. Besides, there are many phenotypic abnormalities in cloned animals, containing frequent embryonic and perinatal death and placentomegaly, and the underlying mechanisms remain unclear （Yang et al, 2007）.
基金supported by the National Natural Science Foundation of China(52321005)the Guangdong Basic and Applied Basic Research Foundation(2023A1515012383 and 2024A1515030138)+1 种基金the State Key Laboratory of Urban Water Resource and Environment(Harbin Institute of Technology,2021TS30)the Shenzhen Science and Technology Program(KQTD20190929172630447 and KCXFZ20211020163404007).
文摘Constructed wetlands(CWs) are a promising method to treat effluent from wastewater treatment plants(WWTPs),However,low carbon/nitrogen(C/N) ratios of the influent inhibit denitrification in CWs,resulting in poor nitrogen removal efficiency.Herein,we compared traditional(control),biochar(BC), andβ-cyclodextrin-fu nctionalized biochar(BC@β-CD) CW systems to investigate nitrogen removal from influent with low C/N ratios,and the mechanisms that enhance this process.The highest nitrogen removal rates were observed in the BC@β-CD group,with rates 45.89% and 42.48% higher than those of the control,accompanied by a 70.57% and 85.45% decrease in nitrous oxide release,when the C/N ratio decreased from4 to 2,respectively.Metagenomic and enzymatic analyses indicated that BC@β-CD enhances nitrogen removal by coordinately promoting carbon metabolism and increasing denitrification enzyme activities,without affecting microbial species diversity in CWs.Structural equation modeling confirmed that the foremost advantages of BC@β-CD were effective electron generation and transportation resulting from increased activities of nicotinamide adenine dinucleotide(NADH) dehydrogenase and the electron transfer system(ETS),thereby strategically reallocating more carbon metabolic flow to support denitrification.Our results show that the application of BC@β-CD in CWs to optimize the reallocation of electrons from carbon metabolism is a feasible strategy to enhance denitrification under low C/N conditions.
文摘Nanopowder of Cr：GGG and nanopowder of Cr,Nd：GGG with different concentrations of Cr3＋ ranging from 0.1 at.% to 1.5 at.% were synthesized by the sol-gel method using acetic acid and ethylene glycol. Thermal gravimetric analysis and differential scanning calorimetry （TGA-DSC）, X-ray diffraction （XRD） and photoluminescence spectroscopy were used to characterize the powder. The crystallite size was about 58 nm when treated at 1000 oC for 2 h. Cr3＋ photoluminescence spectrum in GGG showed a broad band emission around 730 nm. The intensity of this band decreased when co-doped with Nd, indicating an efficient energy transfer from Cr3＋ to Nd3＋. Photoluminescence intensity of Nd in Cr,Nd：GGG at 1.06μm showed that the optimum concentration of Cr3＋ was about 1 at.% （more or less） for 1 at.% Nd3＋. This result was also confirmed by chromium fluorescence decay rate analysis. Energy transfer efficiency was found to be about 84% for 1 at.% concentration of each chromium and neodymium.
基金the National Key Research and Development Program of China(Nos.2022YFB3803600 and 2018YFB1502001)National Natural Science Foundation of China(Nos.22238009,51932007,U1905215,52073223,52173065,and 52202375)+2 种基金the Natural Science Foundation of Hubei Province of China(No.2022CFA001)China Postdoctoral Science Foundation(Nos.2021TQ0311 and 2021M702990)International Postdoc-toral Exchange Fellowship Program(No.PC2022051).
文摘Electron donors(EDs)are widely used to improve the H 2 production performance of Schottky junction photocatalysts,but the functions of EDs are still unknown from the perspective of electron transfer dy-namics.Herein,Pt nanocluster-decorated CdS nanorod is successfully prepared to construct a typical CdS/Pt Schottky junction.Pt nanoclusters with a diameter of∼2 nm are deposited on the surface of CdS nanorods by in situ photoreduction at sub-zero temperature.The CdS/Pt photocatalyst using lactic acid shows a higher H_(2)production rate of 4762μmol g^(-1)h^(-1)compared to that using methanol,tri-ethanolamine,and glycerol.To understand the cause,the dynamics of photogenerated carriers in CdS/Pt photocatalysts during ED-assisted H_(2)production are revealed by femtosecond transient absorption spec-troscopy.Among the four organic EDs,lactic acid enables the fastest electron transfer rate of 1.8×10^(9)s^(-1)and the highest electron transfer efficiency of 76%at the CdS/Pt interface due to the most efficient hole consumption.This work sheds light on the importance of efficient interfacial electron transfer for im-proving the photocatalytic performance of Schottky junction photocatalysts.
基金Supported by the Research Start-up Foundation for Talents of Northwest A&F University of China under Grant Nos.Z111021106 and Z111021307
文摘In this paper, we use a nonlinear decohering quantum model to study the initial step of photosynthesis which is an ultrafast transfer process of absorption the sunlight by light-harvesting complexes and electronic excitation transfer to the reaction center(RC). In this decohering model, the Hamiltonian of the system commutes with the systemenvironment interaction. We take B850 ring of light-harvesting complex II(LH-II) in purple bacteria as an example to calculate the efficiency of the energy transfer as a function of time. We find that the environmental noise can make the LH-II have stable energy transfer efficiency over a long time. This is to say that the environmental noise which is the decohering source has advantage of the energy transfer in the process of photosynthesis.
基金supported by the National Nature Science Foundation of China(Nos.52202335 and 52171227)Natural Science Foundation of Jiangsu Province(No.BK20221137)National Key R&D Program of China(2024YFE0108500).
文摘Wide-temperature applications of sodium-ion batteries(SIBs)are severely limited by the sluggish ion insertion/diffusion kinetics of conversion-type anodes.Quantum-sized transition metal dichalcogenides possess unique advantages of charge delocalization and enrich uncoordinated electrons and short-range transfer kinetics,which are crucial to achieve rapid low-temperature charge transfer and high-temperature interface stability.Herein,a quantum-scale FeS_(2) loaded on three-dimensional Ti_(3)C_(2) MXene skeletons(FeS_(2) QD/MXene)fabricated as SIBs anode,demonstrating impressive performance under wide-temperature conditions(−35 to 65).The theoretical calculations combined with experimental characterization interprets that the unsaturated coordination edges of FeS_(2) QD can induce delocalized electronic regions,which reduces electrostatic potential and significantly facilitates efficient Na+diffusion across a broad temperature range.Moreover,the Ti_(3)C_(2) skeleton reinforces structural integrity via Fe-O-Ti bonding,while enabling excellent dispersion of FeS_(2) QD.As expected,FeS_(2) QD/MXene anode harvests capacities of 255.2 and 424.9 mAh g^(−1) at 0.1 A g^(−1) under−35 and 65,and the energy density of FeS_(2) QD/MXene//NVP full cell can reach to 162.4 Wh kg^(−1) at−35,highlighting its practical potential for wide-temperatures conditions.This work extends the uncoordinated regions induced by quantum-size effects for exceptional Na^(+)ion storage and diffusion performance at wide-temperatures environment.
基金supported by the 100 Talents Program of the Chinese Academy of Sciences, National Natural Science Foundation of China (Nos. 21173226, 21376247)State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences (Nos. MPCS-2011-D-08, MPCS-2010-C-02)
文摘A 1-dodecanethiol-based phase-transfer protocol is developed for the extraction of noble metal ions from aqueous solution to a hydrocarbon phase, which calls for first mixing the aqueous metal ion solution with an ethanolic solution of 1-dodecanethiol, and then extracting the coordination compounds formed between noble metal ions and 1-dodecanethiol into a non-polar organic solvent. A number of characterization techniques, including inductively coupled plasma atomic emission spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis demonstrate that this protocol could be applied to extract a wide variety of noble metal ions from water to dichlorometh- ane with an efficiency of 〉96%, and has high selectivity for the separation of the noble metal ions from other transition metals. It is therefore an attractive alternative for the extraction of noble metals from water, soil, or waste printed circuit boards.
基金supported by the National Natural Science Foundation of China (No. 51473092)the Shanghai Rising-Star Program (No. 15QA1402500)
文摘Fabrication of efficient solid luminogens with tunable emission is both fundamentally significant and technically important. Herein, based on our previous strategy for the construction of efficient and multifunctional solid luminogens through the combination of diverse aggregation-induced emission （ALE） units with other functional moieties, a group of luminophores with electron donor-acceptor （D-A） structure and typical intramolecular charge transfer （ICT） characteristics, namely CZ-DCDPP, DPA-DCDPP and DBPA-DCDPP were synthesized and investigated. The presence of twisting and AlE-active 2,3- dicyano-S,6-diphenylpyrazine （DCDPP） moiety endows them highly emissive in the solid states, whereas the introduction of arylamines with varied electron-donating capacity and different conjugation render them with tunable solid emissions from green to red. While CZ-DCDPP and DPA-DCDPP solids exhibit distinct mechanochromism, both DPA-DCDPP and DBPA-DCDPP solids can generate efficient red emission. Owing to their high efficiency, remarkable thermal and morphological stabilities and moreover red emission, they are promising for diverse optoelectronic and biological applications.
基金funding frown the Chinese National Key Programme for Developing Basic Sciences，the National Natural Science Foundation of China，the Key Program of the Chinese Academy of Sciences，the National Natural Science Foundation of China，the Foundation for Excellent Young Scholars of CAREERI
文摘The flux-variance similarity relation and the vertical transfer of scalars exhibit dissimilarity over different types of surfaces, resulting in different parameterization approaches of relative transport efficiency among scalars to estimate turbulent fluxes using the flux-variance method. We investigated these issues using eddycovariance measurements over an open, homogeneous and flat grassland in the eastern Tibetan Plateau in summer under intermediate hydrological conditions during rainy season. In unstable conditions, the temperature, water vapor, and CO2 followed the flux-variance similarity relation, but did not show in precisely the same way due to different roles （active or passive） of these scalars. Similarity constants of temperature, water vapor and CO2 were found to be 1.12, 1.19 and 1.17, respectively. Heat transportation was more eft% cient than water vapor and CO2. Based on the estimated sensible heat flux, five parameterization methods of relative transport efficiency of heat to water vapor and CO2 were examined to estimate latent heat and CO2 fluxes. The strategy of local determination of flux-variance similarity relation is recommended for the estimation of latent heat and CO2 fluxes. This approach is better for representing the averaged relative transport efficiency, and technically easier to apply, compared to other more complex ones.
基金Supported by the National Basic Research Program of China （2009CB219905） National Natural Science Foundation of China（21176172）+1 种基金 National Key Technology R＆D Program （2011BAE03B07） Program for Changjiang Scholars and Innovative Research Team in University （IRT0936） The authors are also grateful to Institute of Metal, Chinese Academy of Science for providing SiC foam elements, and their support and discussions.
文摘The novel SiC foam valve tray was made of thin slices of SiC foam material with a high specific surfacearea. Hydrodynamic performances of the novel SiC foam valve tray were studied with air-water system at atmos-pheric pressure. These performance parameters included pressure drop, entrainment, weeping and clear liquidheight. The mass transfer efficiency of the SiC foam valve tray was measured in laboratory plate column. Comparedwith the F1 float valve tray, the dry pressure drop was decreased about 25%, the entrainment rate was about 70%lower at high gas load, the weeping was much better, and the mass transfer efficiency was far higher. Thus, theoverall performance of the novel SiC foam valve tray was better than that of F1 float valve tray.
文摘Solvent extraction phenol from coal tar were carried out with novel composite YH-3 as extraction agent, and the high flux centrifugal extractor was used as extraction device. Under the premise of high phenol extraction rate, composite YH-3 extraction agent reduces n-n interaction between phenolic compounds and aromatic hydrocarbons, thus decreasing the entrainment of neutral oil. The optimization of operation conditions, such as the diameter of heavy phase weir HWD, the flow ratio, the total flow rate and the rotation speed, are necessary. For single stage extraction experiment, the mass transfer efficiency was up to 84% while the rate of extraction agent loss was lower than 0.28% with the operation conditions of 29 mm of the heavy phase weir diameter （HWD）, 1：1-1.4：1 of the flow ratio range, 160-200 mL/min of the total flow rate and the rotation speed varied from 2200 to 2600 r/min. For three stage counter-current test, the mass transfer efficiency reached up to 92.6% with the optimum operation condition of 29 mm of the HWD, 1：1 of the flow ratio, 200 rnL/min of the total flow rate and 2400 r/rain of the rotation speed. The results indicated that phenol could be extracted effectively from coal tar in the process of multistage continuous count current centrifugal extraction.
基金Project(2011CB706606) supported by the National Basic Research of ChinaProject(51405375) supported by the National Natural Science Foundation of China
文摘The vortex formed around the rolling ball and the high pressure region formed around the ball-raceway contact zone are the principle factors that barricades the lubricant entering the bearing cavity, and further causes improper lubrication. The investigation of the air phase flow inside the bearing cavity is essential for the optimization of the oil-air two-phase lubrication method. With the revolutionary reference frame describing the bearing motion, a highly precise air phase flow model inside the angular contact ball bearing cavity was build up. Comprehensive factors such as bearing revolution, ball rotation, and cage structure were considered to investigate the influences on the air phase flow and heat transfer efficiency. The aerodynamic noise was also analyzed. The result shows that the ball spinning leads to the pressure rise and uneven pressure distribution. The air phase velocity, pressure and cage heat transfer efficiency increase as the revolving speed increases. The operating noise is largely due to the impact of the high speed external flow on the bearing. When the center of the oil-air outlet fixes near the inner ring, the aerodynamic noise is reduced. The position near the inner ring on the bigger axial side is the ideal position to fix the lubricating device for the angular contact ball bearing.
