A heavy-ion irradiation experiment is studied in digital storage cells with different design approaches in 130?nm CMOS bulk Si and silicon-on-insulator (SOI) technologies. The effectiveness of linear energy transf...A heavy-ion irradiation experiment is studied in digital storage cells with different design approaches in 130?nm CMOS bulk Si and silicon-on-insulator (SOI) technologies. The effectiveness of linear energy transfer (LET) with a tilted ion beam at the 130?nm technology node is obtained. Tests of tilted angles θ=0 ° , 30 ° and 60 ° with respect to the normal direction are performed under heavy-ion Kr with certain power whose LET is about 40?MeVcm 2 /mg at normal incidence. Error numbers in D flip-flop chains are used to determine their upset sensitivity at different incidence angles. It is indicated that the effective LETs for SOI and bulk Si are not exactly in inverse proportion to cosθ , furthermore the effective LET for SOI is more closely in inverse proportion to cosθ compared to bulk Si, which are also the well known behavior. It is interesting that, if we design the sample in the dual interlocked storage cell approach, the effective LET in bulk Si will look like inversely proportional to cosθ very well, which is also specifically explained.展开更多
Magnetic radiation phenomena appear inevitably in the magnetic-resonance wireless power transfer (MR-WPT) system, and regarding this problem the magnetic-shielding scheme is applied to improve the electromagnetic pe...Magnetic radiation phenomena appear inevitably in the magnetic-resonance wireless power transfer (MR-WPT) system, and regarding this problem the magnetic-shielding scheme is applied to improve the electromagnetic performance in engineering. In this study, the shielding effectiveness of a two-coil MR-WPT system for different material shields is analyzed in theory using Moser's formula and Schelkunoff's formula. On this basis a candidate magnetic-shielding scheme with a double-layer structure is determined, which has better shielding effectiveness and coils coupling coefficient. Finally, some finite element simulation results validate the correctness of the theoretical analysis, and the shielding effectiveness with the double-layer shield in maximum is 30?dB larger than the one with the single-layer case.展开更多
Due to the advantages of low energy consumption and high CO_(2) selectivity, the development of solid amine-based materials has been regarded as a hot research topic in the field of DAC for the past decades.The adsorp...Due to the advantages of low energy consumption and high CO_(2) selectivity, the development of solid amine-based materials has been regarded as a hot research topic in the field of DAC for the past decades.The adsorption capacity and stability over multiple cycles have been the top priorities for evaluation of practical application value. Herein, we synthesized a novel DAC material by loading TEPA onto defect-rich Mg_(0.55)Al-O MMOs with enhanced charge transfer effect. The optimal Mg_(0.55)Al-O-TEPA67% demonstrates the highest CO_(2)uptake of(3.0 mmol g^(-1)) and excellent regenerability, maintaining ~90% of the initial adsorption amount after 80 adsorption/desorption cycles. The in situ DRIFTS experiments suggested the formation of bicarbonate species under wet conditions. DFT calculations indicated that the stronger bonding between Mg_(0.55)Al-O support and solid amine was caused by the abundance of oxygen defects on MMOs confirmed by XPS and ESR, which favors the charge transfer between the support and amine,resulting in intense interaction and excellent regenerability. This work for the first time conducted comprehensive and systematic investigation on the stabilization mechanism for MMOs supported solid amine adsorbents with highest uptake and superior cyclic stability in depth, which is different from the most popular SiO_(2)-support, thus providing facile strategy and comprehensive theoretical mechanism support for future research about DAC materials.展开更多
The kinetics of ion exchange between Ca2+, Mg2+, Co(Ⅱ), Cu(Ⅱ),Ni(Ⅱ), Fe(Ⅲ), y3+ or Sm3+ , respectively, in 0.50 mol/L HC1 and H+ on macrorecticular sulfonic ion exchange resin and the kinetics of the same reaction...The kinetics of ion exchange between Ca2+, Mg2+, Co(Ⅱ), Cu(Ⅱ),Ni(Ⅱ), Fe(Ⅲ), y3+ or Sm3+ , respectively, in 0.50 mol/L HC1 and H+ on macrorecticular sulfonic ion exchange resin and the kinetics of the same reactions (M -H exchange) when Mn(Ⅱ) coexisted in resin phase as accelerating ion were studied. The accelerating effect manifested and its rule are consistent with the accelerating effect theory based on the concept concerned with adsorption electrical double layer which has been suggested in a previous paper published.展开更多
The present investigation addresses the simultaneous effects of heat and mass transfer in the mixed convection peristaltic flow of viscous fluid in an asymmetric channel. The channel walls exhibit the convective bound...The present investigation addresses the simultaneous effects of heat and mass transfer in the mixed convection peristaltic flow of viscous fluid in an asymmetric channel. The channel walls exhibit the convective boundary conditions. In addition, the effects due to Soret and Dufour are taken into consideration. Resulting problems are solved for the series solutions. Numerical values of heat and mass transfer rates are displayed and studied. Results indicate that the concentration and temperature of the fluid increase whereas the mass transfer rate at the wall decreases with increase of the mass transfer Biot number. Furthermore, it is observed that the temperature decreases with the increase of the heat transfer Biot number.展开更多
in recent years research investigating various health benefits of Taiji practice has markedly increased. Despite this growing scientific interest, essential questions such as to what extent a Taiji course may exert no...in recent years research investigating various health benefits of Taiji practice has markedly increased. Despite this growing scientific interest, essential questions such as to what extent a Taiji course may exert noticeable effects in participants' everyday life, what these effects are, and how and where potential transfer effects occur, have hardly been considered. The aim of our study was to explore transfer effects from a Taiji course into participants' daily lives. METHODS: We conducted a longitudinal observational study in 45 healthy participants at the end of their three-month Taiji beginner course (tpl) and at two months (tp2) as well as one year after course completion (tp3). Participants were asked to report their Taiji practice behavior at all time points, as well as to rate and describe perceived transfer effects of Taiji course contents on their daily life at tpl and tp3. RESULTS: Transfer effects were reported by 91.1% of all respondents after course completion (tpl) and persisted in 73.3% at the one-year follow-up assessment (tp3), counting "increase of self-efficacy", "improvement of stress management", and "increase of body awareness" as the most frequently mentioned effects. Transfer effects predominantly occurred in participants' work and social environments, as well as during everyday activities in public areas. While self- reliant Taiji practice frequency significantly decreased from 82.2% at tpl to 55.6% at tp3 (P 〈 0.001), the magnitude of self-reported transfer effects did not (P = 0.35). As explorative analyses revealed, regular Taiji course attendance was highly correlated with stronger transfer effects at tpl (r = 0.51; P 〈 0.001) and tp3 (r = 0.35; P = 0.020). Participants reporting high self-reliant Taiji practice frequency at tp2 were likely to maintain a regular practice routine at tp3 (r = 0.42; P 〈 0.004), whereas self-reliant practice frequency and transfer effects at tpl were positively correlated with self-reliant practice frequency at tp3 on a trend level (r 〈 0.27; P 〉 0.08). CONCLUSION: Our data underline the importance of regular course participation for pronounced and long lasting transfer effects into participants' everyday life. We discuss that several context and process-related aspects of a Taiji intervention are potentially relevant factors for enhancement of transfer effect.展开更多
Flow thermomechanics in reactive porous media is of importance in industry including the thermal processing of fossil fuel(coking understood as a slow pyrolysis)involving devolatilisation.On the way to provide a detai...Flow thermomechanics in reactive porous media is of importance in industry including the thermal processing of fossil fuel(coking understood as a slow pyrolysis)involving devolatilisation.On the way to provide a detailed description of the process,a multi-scale approach was chosen to estimate effective transport coefficients.For this case the Lattice Boltzmann method(LBM)was used due to its advantages to accurately model multi-physics and chemistry in a random geometry of granular media.After account for earlier studies,the paper presents description of the model with improved boundary conditions and a benchmark case.Results from meso-scale LBM calculations are presented and discussed regarding the spatial resolution and the choice of relaxation parameter along its influence on the accuracy compared with empirical formulae.Regarding the estimation of effective thermal conductivity coefficient it is shown that occurrence of devolatilization has a crucial effect by reducing heat transfer.Some quantitative results characterise the propagation of thermal front;also presented is the evolution of effective thermal conductivity.The work is a step forward towards a physically sound simulation of thermal processing of fossil fuel.展开更多
Alloimmunization was combined with lympho-kine activated killer (LAK) cells to assess its effect on mammary carcinoma in rats. The animals were injected with both irradiated allosplenocytes and syngeneic LAK cells. Me...Alloimmunization was combined with lympho-kine activated killer (LAK) cells to assess its effect on mammary carcinoma in rats. The animals were injected with both irradiated allosplenocytes and syngeneic LAK cells. Metastatic lung nodules were markedly reduced using combined therapy when compared with the transfer of LAK cells or alloimmuni-zation alone. IL-2 activity in the serum of alloim-munized rats could be detected. This activity, maintained in vivo for one week, may be responsible for enhancing the antitumor effect of transferred LAK cells.展开更多
We demonstrate a triple-pass scheme for coherent transfer of optical frequency and the delay effect on the fiber phase noise compensation. It is theoretically proved that the delay effect consists of both fiber delay ...We demonstrate a triple-pass scheme for coherent transfer of optical frequency and the delay effect on the fiber phase noise compensation. It is theoretically proved that the delay effect consists of both fiber delay and servo delay. The delay effect confines the servo bandwidth within 1/8 and induces a residual fiber phase noise after noise compensation. For a 25-km-long fiber, the servo bandwidth is found to be around 1 k Hz, and the fiber phase noise is suppressed approaching to the theoretical limitation. The triple-pass scheme enables the simultaneous transfer of optical frequency to multiple remote users. The performance of noise compensator in the triple-pass scheme can achieve a similar level result compared with that in the double-pass scheme.展开更多
Miniaturization of electronic package leads to high heat density and heat accumulation in electronics device, resulting in short life time and premature failure of the device. Junction temperature and thermal resistan...Miniaturization of electronic package leads to high heat density and heat accumulation in electronics device, resulting in short life time and premature failure of the device. Junction temperature and thermal resistance are the critical parameters that determine the thermal management and reliability in electronics cooling. Metal oxide field effect transistor(MOSFET)is an important semiconductor device for light emitting diode-integrated circuit(LED IC) driver application, and thermal management in MOSFET is a major challenge. In this study, investigations on thermal performance of MOSFET are performed for evaluating the junction temperature and thermal resistance. Suitable modifications in FR4 substrates are proposed by introducing thermal vias and copper layer coating to improve the thermal performance of MOSFET. Experiments are conducted using thermal transient tester(T3ster) at 2.0 A input current and ambient temperature varying from25℃ to 75℃. The thermal parameters are measured for three proposed designs: FR4 with circular thermal vias, FR4 with single strip of copper layer and embedded vias, and FR4 with I-shaped copper layer, and compared with that of plain FR4 substrate. From the experimental results, FR4I-shaped shows promising results by 33.71% reduction in junction temperature and 54.19% reduction in thermal resistance. For elevated temperature, the relative increases in junction temperature and thermal resistance are lower for FR4I-shaped than those for other substrates considered. The introduction of thermal vias and copper layer plays a significant role in thermal performance.展开更多
The effect of the solid matrix and porosity of the porous medium are first introduced to the study of power-law nanofluids, and the Marangoni boundary layer flow with heat generation is investigated. Two cases of soli...The effect of the solid matrix and porosity of the porous medium are first introduced to the study of power-law nanofluids, and the Marangoni boundary layer flow with heat generation is investigated. Two cases of solid matrix of porous medium including glass balls and aluminum foam are considered. The governing partial differential equations are simplified by dimensionless variables and similarity transformations, and are solved numerically by using a shooting method with the fourth-fifth-order Runge-Kutta integration technique. It is indicated that the increase of the porosity leads to the enhancement of heat transfer in the surface of the Marangoni boundary layer flow.展开更多
The braking quality is considered the main execution of the adaptive control framework that impacts the vehicle safety and rides solace astoundingly notably the stopping distance.This research work aims to create a pa...The braking quality is considered the main execution of the adaptive control framework that impacts the vehicle safety and rides solace astoundingly notably the stopping distance.This research work aims to create a pattern and design of an electromechanically adjusted lever that multiplies the applied braking force depending on the inputs given by the sensors to reduce the stopping distance of the vehicle.It is carried out using two main parts of the two-wheeler vehicle:thefirst part deals with the detection of load acting on the vehicle and identifying the required braking force to be applied,and the second part deals with the micro-controller which activates the stepper motor for varying the mechanical leverage ratio from various loads on the vehicle using two actively movable wedges.The electromechanically operated variable braking force system is developed to actuate the braking system based on the load on the motorcycle.The MATLAB simulation and experimental work are carried out for various loading(driver and pillion)conditions on a two-wheeler.The results indicate that the proposed electronically operated braking system is more effective than the conventional braking system for various loads and vehicle speeds.Specifically,the stopping distance of the vehicle is decreased significantly by about 4.9%between the con-ventional braking system and the simulated proposed system.Further,the experi-mental results show that the stopping distance is condensed by about 4.1%.The validation between simulated and experimental results revealed a great deal with the least error percentage of about 0.8%.展开更多
Considering the coupled heat transfer effect induced by parallel cross-river road tunnels, the long-term soil temperature variations of shallow sections of cross-river tunnels under the river beach are predicted using...Considering the coupled heat transfer effect induced by parallel cross-river road tunnels, the long-term soil temperature variations of shallow sections of cross-river tunnels under the river beach are predicted using the finite difference method for numerical simulation. The boundary conditions and the initial values are determined by in situ observations and numerical iterations.The simulation results indicate that the ultimate calculated steady heat transfer time is 68 years, and most of the heat transfer is completed in 20 years.The initial constant temperature soil surrounding the tunnels is transformed to an annually variable one.An obvious temperature-varying region of the surrounding soil is discovered within 5 m from the tunnel exterior, as well as within the entire range of soil between the two tunnels.The maximum temperature increase value reaches 7.14 ℃ and the maximum peak-to-valley value of annual temperature increase reaches 10 ℃.The temperature variation of soils surrounding tunnels below 10 m is completely controlled by the heat transfer from the tunnels.The coupled heat transfer effect is confirmed because the ultimate steady temperature of soil between the two tunnels is higher than the ones along other positions.Moreover, the regression model comprising a series of univariate functions is proposed for the annual soil temperature fluctuation estimation for the locations varied distances around the tunnel.This investigation is beneficial to gain an insight into the long-term variation tendencies of local engineering geological conditions of the river beach above shallow sections of the cross-river road tunnels.展开更多
Nano-ring-type magnetic tunnel junctions (NR-MTJs) with the layer structure of Ta(5)/Ir22Mn78(10)/ Co75Fe25(2)/Ru(0.75)/CoooFe20B20(3)/Al(0.6)-oxide/Co60Fe20B20(2.5)/Ta(3)/Ru(5) (thickness unit:...Nano-ring-type magnetic tunnel junctions (NR-MTJs) with the layer structure of Ta(5)/Ir22Mn78(10)/ Co75Fe25(2)/Ru(0.75)/CoooFe20B20(3)/Al(0.6)-oxide/Co60Fe20B20(2.5)/Ta(3)/Ru(5) (thickness unit: nm) were nano-fabricated on the Si(100)/SiO2 substrate using magnetron sputtering deposition combined with the optical lithography, electron beam lithography (EBL) and Ar ion-beam etching techniques. The smaller NR-MTJs with the inner- and outer-diameter of around 50 and 100 nm and also their corresponding NR-MTJ arrays were nano-patterned. The tunnelling magnetoresistance (TMR & R) versus driving current (I) loops for a spin-polarized current switching were measured, and the TMR ratio of around 35% at room temperature were observed. The critical values of switching current for the free Co60Fe20B20 layer relative to the reference Co6oFe2oB2o layer between parallel and anti-parallel magnetization states were between 0.50 and 0.75 mA in such NR-MTJs. It is suggested that the applicable MRAM fabrication with the density and capacity higher than 256 Mbit/inch2 even 6 Gbite/inch2 are possible using both I NR-MTJ+1 transistor structure and current switching mechanism based on based on our fabricated 4×4 MRAM demo devices.展开更多
A heat transfer model for three-fluid separated heat pipe exchanger was analyzed,and the temperature transfer matrix for general three-fluid separated heat exchanger working in parallel-flow or counter-flow mode was o...A heat transfer model for three-fluid separated heat pipe exchanger was analyzed,and the temperature transfer matrix for general three-fluid separated heat exchanger working in parallel-flow or counter-flow mode was obtained.It was found that the forms of temperature transfer matrix are similar for heat pipe rows with equal or different heat transfer surface area.Furthermore,by using the temperature transfer matrix of the heat pipe exchanger,the relationship between heat transfer effectiveness θ 1,θ 2 and M,NTU,U,Δt i were derived for the exchanger operating in parallel-flow or counter-flow mode,and a simple special example was adopted to demonstrate the correctness of these relationships.展开更多
The performance of an electrocatalyst, which is needed e.g. for key energy conversion reactions such as hydrogen evolution, oxygen reduction or CO2 reduction, is determined not only by the inherent structure of active...The performance of an electrocatalyst, which is needed e.g. for key energy conversion reactions such as hydrogen evolution, oxygen reduction or CO2 reduction, is determined not only by the inherent structure of active sites but also by the properties of the interfacial structures at catalytic surfaces. Ionic liquids(ILs), as a unique class of metal salts with melting point below 100 ℃, present themselves as ideal modulators for manipulations of the interfacial structures. Due to their excellent properties such as good chemical stability, high ionic conductivity, wide electrochemical windows and tunable solvent properties the performance of electrocatalysts can be substantially improved through ILs. In the current minireview, we highlight the critical role of the IL phase at the microenvironments created by the IL, the liquid electrolyte, catalytic nanoparticles and/or support materials, by detailing the promotional effect of IL in electrocatalysis as reaction media, binders, and surface modifiers. Updated exemplary applications of IL in electrocatalysis are given and moreover, the latest developments of IL modified electrocatalysts following the "Solid Catalyst with Ionic Liquid Layer(SCILL)" concept are presented.展开更多
Recent progresses in magnetic tunnel junctions with perpendicular magnetic anisotropy (PMA) are reviewed and summarized. At first, the concept and source of perpendicular magnetic anisotropy (PMA) are introduced. ...Recent progresses in magnetic tunnel junctions with perpendicular magnetic anisotropy (PMA) are reviewed and summarized. At first, the concept and source of perpendicular magnetic anisotropy (PMA) are introduced. Next, a historical overview of PMA materials as magnetic electrodes, such as the RE-TM alloys TbFeCo and GdFeCo, novel tetragonal manganese alloys Mn-Ga, L10-ordered (Co, Fe)/Pt alloy, multilayer film [Co, Fe, CoFe/Pt, Pd, Ni, AU]N, and ultra-thin magnetic metal/oxidized barrier is offered. The other part of the article focuses on the optimization and fabrication of CoFeB/MgO/CoFeB p-MTJs, which is thought to have high potential to meet the main demands for non-volatile magnetic random access memory.展开更多
In the process of bulk photopolymerization of styrene initiated by AIBN decomposition polyvinyl benzophenone (PVB) can supply an effective cage for triplet-triplet energy transfer between PVB macromolecules and small ...In the process of bulk photopolymerization of styrene initiated by AIBN decomposition polyvinyl benzophenone (PVB) can supply an effective cage for triplet-triplet energy transfer between PVB macromolecules and small molecules of AIBN to influence the molecular weight of polystyrene in weak magnetic field (less than 0.035T), that was different from the case of polyvinyl naphthalene (PVN) which supplied cages for this system only in the stronger magnetic field (more than 0.2 T) studies. It was found that in the same conditions, PVN could exert more tremendous influences on the bulk photopolymerizatiou system of styrene than PVB because in the stronger magnetic field the triplet PVN had much longer life time than PVB.展开更多
In this paper,a novel mixed wavelet-learning method is developed for predicting macroscopic effective heat transfer conductivities of braided composite materials with heterogeneous thermal conductivity.This innovative...In this paper,a novel mixed wavelet-learning method is developed for predicting macroscopic effective heat transfer conductivities of braided composite materials with heterogeneous thermal conductivity.This innovative methodology integrates respective superiorities of multi-scale modeling,wavelet transform and neural networks together.By the aid of asymptotic homogenization method(AHM),off-line multi-scalemodeling is accomplished for establishing thematerial databasewith highdimensional and highly-complexmappings.Themulti-scalematerial database and the wavelet-learning strategy ease the on-line training of neural networks,and enable us to efficiently build relatively simple networks that have an essentially increasing capacity and resisting noise for approximating the high-complexity mappings.Moreover,it should be emphasized that the wavelet-learning strategy can not only extract essential data characteristics from the material database,but also achieve a tremendous reduction in input data of neural networks.The numerical experiments performed using multiple 3D braided composite models verify the excellent performance of the presentedmixed approach.The numerical results demonstrate that themixedwaveletlearningmethodology is a robustmethod for computing themacroscopic effective heat transfer conductivities with distinct heterogeneity patterns.The presentedmethod can enormously decrease the computational time,and can be further expanded into estimating macroscopic effective mechanical properties of braided composites.展开更多
基金Supported by the Key Laboratory of Microsatellites,Chinese Academy of Sciences
文摘A heavy-ion irradiation experiment is studied in digital storage cells with different design approaches in 130?nm CMOS bulk Si and silicon-on-insulator (SOI) technologies. The effectiveness of linear energy transfer (LET) with a tilted ion beam at the 130?nm technology node is obtained. Tests of tilted angles θ=0 ° , 30 ° and 60 ° with respect to the normal direction are performed under heavy-ion Kr with certain power whose LET is about 40?MeVcm 2 /mg at normal incidence. Error numbers in D flip-flop chains are used to determine their upset sensitivity at different incidence angles. It is indicated that the effective LETs for SOI and bulk Si are not exactly in inverse proportion to cosθ , furthermore the effective LET for SOI is more closely in inverse proportion to cosθ compared to bulk Si, which are also the well known behavior. It is interesting that, if we design the sample in the dual interlocked storage cell approach, the effective LET in bulk Si will look like inversely proportional to cosθ very well, which is also specifically explained.
基金Supported by the National Natural Science Foundation of China under Grant No 51377185
文摘Magnetic radiation phenomena appear inevitably in the magnetic-resonance wireless power transfer (MR-WPT) system, and regarding this problem the magnetic-shielding scheme is applied to improve the electromagnetic performance in engineering. In this study, the shielding effectiveness of a two-coil MR-WPT system for different material shields is analyzed in theory using Moser's formula and Schelkunoff's formula. On this basis a candidate magnetic-shielding scheme with a double-layer structure is determined, which has better shielding effectiveness and coils coupling coefficient. Finally, some finite element simulation results validate the correctness of the theoretical analysis, and the shielding effectiveness with the double-layer shield in maximum is 30?dB larger than the one with the single-layer case.
基金supported by the Fundamental Research Funds for the Central Universities (2019JQ03015)the National Natural Science Foundation of China (42075169, U1810209)the Beijing Municipal Education Commission through the Innovative Transdisciplinary Program “Ecological Restoration Engineering”。
文摘Due to the advantages of low energy consumption and high CO_(2) selectivity, the development of solid amine-based materials has been regarded as a hot research topic in the field of DAC for the past decades.The adsorption capacity and stability over multiple cycles have been the top priorities for evaluation of practical application value. Herein, we synthesized a novel DAC material by loading TEPA onto defect-rich Mg_(0.55)Al-O MMOs with enhanced charge transfer effect. The optimal Mg_(0.55)Al-O-TEPA67% demonstrates the highest CO_(2)uptake of(3.0 mmol g^(-1)) and excellent regenerability, maintaining ~90% of the initial adsorption amount after 80 adsorption/desorption cycles. The in situ DRIFTS experiments suggested the formation of bicarbonate species under wet conditions. DFT calculations indicated that the stronger bonding between Mg_(0.55)Al-O support and solid amine was caused by the abundance of oxygen defects on MMOs confirmed by XPS and ESR, which favors the charge transfer between the support and amine,resulting in intense interaction and excellent regenerability. This work for the first time conducted comprehensive and systematic investigation on the stabilization mechanism for MMOs supported solid amine adsorbents with highest uptake and superior cyclic stability in depth, which is different from the most popular SiO_(2)-support, thus providing facile strategy and comprehensive theoretical mechanism support for future research about DAC materials.
文摘The kinetics of ion exchange between Ca2+, Mg2+, Co(Ⅱ), Cu(Ⅱ),Ni(Ⅱ), Fe(Ⅲ), y3+ or Sm3+ , respectively, in 0.50 mol/L HC1 and H+ on macrorecticular sulfonic ion exchange resin and the kinetics of the same reactions (M -H exchange) when Mn(Ⅱ) coexisted in resin phase as accelerating ion were studied. The accelerating effect manifested and its rule are consistent with the accelerating effect theory based on the concept concerned with adsorption electrical double layer which has been suggested in a previous paper published.
基金the Higher Education Commission of Pakistan (HEC) for the financial support through Indigenous program
文摘The present investigation addresses the simultaneous effects of heat and mass transfer in the mixed convection peristaltic flow of viscous fluid in an asymmetric channel. The channel walls exhibit the convective boundary conditions. In addition, the effects due to Soret and Dufour are taken into consideration. Resulting problems are solved for the series solutions. Numerical values of heat and mass transfer rates are displayed and studied. Results indicate that the concentration and temperature of the fluid increase whereas the mass transfer rate at the wall decreases with increase of the mass transfer Biot number. Furthermore, it is observed that the temperature decreases with the increase of the heat transfer Biot number.
基金Funding for this study was provided by Stiftung für Komplementrmedizin, Gottfried und Julia Bangerter-Rhyner Stiftung and Parrotia Stiftung
文摘in recent years research investigating various health benefits of Taiji practice has markedly increased. Despite this growing scientific interest, essential questions such as to what extent a Taiji course may exert noticeable effects in participants' everyday life, what these effects are, and how and where potential transfer effects occur, have hardly been considered. The aim of our study was to explore transfer effects from a Taiji course into participants' daily lives. METHODS: We conducted a longitudinal observational study in 45 healthy participants at the end of their three-month Taiji beginner course (tpl) and at two months (tp2) as well as one year after course completion (tp3). Participants were asked to report their Taiji practice behavior at all time points, as well as to rate and describe perceived transfer effects of Taiji course contents on their daily life at tpl and tp3. RESULTS: Transfer effects were reported by 91.1% of all respondents after course completion (tpl) and persisted in 73.3% at the one-year follow-up assessment (tp3), counting "increase of self-efficacy", "improvement of stress management", and "increase of body awareness" as the most frequently mentioned effects. Transfer effects predominantly occurred in participants' work and social environments, as well as during everyday activities in public areas. While self- reliant Taiji practice frequency significantly decreased from 82.2% at tpl to 55.6% at tp3 (P 〈 0.001), the magnitude of self-reported transfer effects did not (P = 0.35). As explorative analyses revealed, regular Taiji course attendance was highly correlated with stronger transfer effects at tpl (r = 0.51; P 〈 0.001) and tp3 (r = 0.35; P = 0.020). Participants reporting high self-reliant Taiji practice frequency at tp2 were likely to maintain a regular practice routine at tp3 (r = 0.42; P 〈 0.004), whereas self-reliant practice frequency and transfer effects at tpl were positively correlated with self-reliant practice frequency at tp3 on a trend level (r 〈 0.27; P 〉 0.08). CONCLUSION: Our data underline the importance of regular course participation for pronounced and long lasting transfer effects into participants' everyday life. We discuss that several context and process-related aspects of a Taiji intervention are potentially relevant factors for enhancement of transfer effect.
文摘Flow thermomechanics in reactive porous media is of importance in industry including the thermal processing of fossil fuel(coking understood as a slow pyrolysis)involving devolatilisation.On the way to provide a detailed description of the process,a multi-scale approach was chosen to estimate effective transport coefficients.For this case the Lattice Boltzmann method(LBM)was used due to its advantages to accurately model multi-physics and chemistry in a random geometry of granular media.After account for earlier studies,the paper presents description of the model with improved boundary conditions and a benchmark case.Results from meso-scale LBM calculations are presented and discussed regarding the spatial resolution and the choice of relaxation parameter along its influence on the accuracy compared with empirical formulae.Regarding the estimation of effective thermal conductivity coefficient it is shown that occurrence of devolatilization has a crucial effect by reducing heat transfer.Some quantitative results characterise the propagation of thermal front;also presented is the evolution of effective thermal conductivity.The work is a step forward towards a physically sound simulation of thermal processing of fossil fuel.
文摘Alloimmunization was combined with lympho-kine activated killer (LAK) cells to assess its effect on mammary carcinoma in rats. The animals were injected with both irradiated allosplenocytes and syngeneic LAK cells. Metastatic lung nodules were markedly reduced using combined therapy when compared with the transfer of LAK cells or alloimmuni-zation alone. IL-2 activity in the serum of alloim-munized rats could be detected. This activity, maintained in vivo for one week, may be responsible for enhancing the antitumor effect of transferred LAK cells.
基金Supported by the National Natural Science Foundation of China under Grant No 61378037the Fundamental Research Funds for the Central Universities under Grant No JUSRP51628B
文摘We demonstrate a triple-pass scheme for coherent transfer of optical frequency and the delay effect on the fiber phase noise compensation. It is theoretically proved that the delay effect consists of both fiber delay and servo delay. The delay effect confines the servo bandwidth within 1/8 and induces a residual fiber phase noise after noise compensation. For a 25-km-long fiber, the servo bandwidth is found to be around 1 k Hz, and the fiber phase noise is suppressed approaching to the theoretical limitation. The triple-pass scheme enables the simultaneous transfer of optical frequency to multiple remote users. The performance of noise compensator in the triple-pass scheme can achieve a similar level result compared with that in the double-pass scheme.
基金Project supported by the Collaborative Research in Engineering,Science&Technology(Grant No.P28C2-13)
文摘Miniaturization of electronic package leads to high heat density and heat accumulation in electronics device, resulting in short life time and premature failure of the device. Junction temperature and thermal resistance are the critical parameters that determine the thermal management and reliability in electronics cooling. Metal oxide field effect transistor(MOSFET)is an important semiconductor device for light emitting diode-integrated circuit(LED IC) driver application, and thermal management in MOSFET is a major challenge. In this study, investigations on thermal performance of MOSFET are performed for evaluating the junction temperature and thermal resistance. Suitable modifications in FR4 substrates are proposed by introducing thermal vias and copper layer coating to improve the thermal performance of MOSFET. Experiments are conducted using thermal transient tester(T3ster) at 2.0 A input current and ambient temperature varying from25℃ to 75℃. The thermal parameters are measured for three proposed designs: FR4 with circular thermal vias, FR4 with single strip of copper layer and embedded vias, and FR4 with I-shaped copper layer, and compared with that of plain FR4 substrate. From the experimental results, FR4I-shaped shows promising results by 33.71% reduction in junction temperature and 54.19% reduction in thermal resistance. For elevated temperature, the relative increases in junction temperature and thermal resistance are lower for FR4I-shaped than those for other substrates considered. The introduction of thermal vias and copper layer plays a significant role in thermal performance.
基金Supported by the National Natural Science Foundation of China under Grant No 51305080
文摘The effect of the solid matrix and porosity of the porous medium are first introduced to the study of power-law nanofluids, and the Marangoni boundary layer flow with heat generation is investigated. Two cases of solid matrix of porous medium including glass balls and aluminum foam are considered. The governing partial differential equations are simplified by dimensionless variables and similarity transformations, and are solved numerically by using a shooting method with the fourth-fifth-order Runge-Kutta integration technique. It is indicated that the increase of the porosity leads to the enhancement of heat transfer in the surface of the Marangoni boundary layer flow.
文摘The braking quality is considered the main execution of the adaptive control framework that impacts the vehicle safety and rides solace astoundingly notably the stopping distance.This research work aims to create a pattern and design of an electromechanically adjusted lever that multiplies the applied braking force depending on the inputs given by the sensors to reduce the stopping distance of the vehicle.It is carried out using two main parts of the two-wheeler vehicle:thefirst part deals with the detection of load acting on the vehicle and identifying the required braking force to be applied,and the second part deals with the micro-controller which activates the stepper motor for varying the mechanical leverage ratio from various loads on the vehicle using two actively movable wedges.The electromechanically operated variable braking force system is developed to actuate the braking system based on the load on the motorcycle.The MATLAB simulation and experimental work are carried out for various loading(driver and pillion)conditions on a two-wheeler.The results indicate that the proposed electronically operated braking system is more effective than the conventional braking system for various loads and vehicle speeds.Specifically,the stopping distance of the vehicle is decreased significantly by about 4.9%between the con-ventional braking system and the simulated proposed system.Further,the experi-mental results show that the stopping distance is condensed by about 4.1%.The validation between simulated and experimental results revealed a great deal with the least error percentage of about 0.8%.
基金The National Natural Science Foundation of China(No.40902076)the Natural Science Foundation of Jiangsu Province(No.BK20141224)
文摘Considering the coupled heat transfer effect induced by parallel cross-river road tunnels, the long-term soil temperature variations of shallow sections of cross-river tunnels under the river beach are predicted using the finite difference method for numerical simulation. The boundary conditions and the initial values are determined by in situ observations and numerical iterations.The simulation results indicate that the ultimate calculated steady heat transfer time is 68 years, and most of the heat transfer is completed in 20 years.The initial constant temperature soil surrounding the tunnels is transformed to an annually variable one.An obvious temperature-varying region of the surrounding soil is discovered within 5 m from the tunnel exterior, as well as within the entire range of soil between the two tunnels.The maximum temperature increase value reaches 7.14 ℃ and the maximum peak-to-valley value of annual temperature increase reaches 10 ℃.The temperature variation of soils surrounding tunnels below 10 m is completely controlled by the heat transfer from the tunnels.The coupled heat transfer effect is confirmed because the ultimate steady temperature of soil between the two tunnels is higher than the ones along other positions.Moreover, the regression model comprising a series of univariate functions is proposed for the annual soil temperature fluctuation estimation for the locations varied distances around the tunnel.This investigation is beneficial to gain an insight into the long-term variation tendencies of local engineering geological conditions of the river beach above shallow sections of the cross-river road tunnels.
基金the State Key Project of Fundamental Research of Ministry of Science and Technology (No. 2006CB932200) the National Natural Science Foundation of China (NSFC, No. 10574156)+2 种基金 the Knowledge Innovation Program of Chinese Aca.demy of Sciencesthe protial support of 0utstanding Young Researcher Foundation (Nos. 50325104 and 50528101) K.C.Wong Education Foundation, Hong Kong.
文摘Nano-ring-type magnetic tunnel junctions (NR-MTJs) with the layer structure of Ta(5)/Ir22Mn78(10)/ Co75Fe25(2)/Ru(0.75)/CoooFe20B20(3)/Al(0.6)-oxide/Co60Fe20B20(2.5)/Ta(3)/Ru(5) (thickness unit: nm) were nano-fabricated on the Si(100)/SiO2 substrate using magnetron sputtering deposition combined with the optical lithography, electron beam lithography (EBL) and Ar ion-beam etching techniques. The smaller NR-MTJs with the inner- and outer-diameter of around 50 and 100 nm and also their corresponding NR-MTJ arrays were nano-patterned. The tunnelling magnetoresistance (TMR & R) versus driving current (I) loops for a spin-polarized current switching were measured, and the TMR ratio of around 35% at room temperature were observed. The critical values of switching current for the free Co60Fe20B20 layer relative to the reference Co6oFe2oB2o layer between parallel and anti-parallel magnetization states were between 0.50 and 0.75 mA in such NR-MTJs. It is suggested that the applicable MRAM fabrication with the density and capacity higher than 256 Mbit/inch2 even 6 Gbite/inch2 are possible using both I NR-MTJ+1 transistor structure and current switching mechanism based on based on our fabricated 4×4 MRAM demo devices.
文摘A heat transfer model for three-fluid separated heat pipe exchanger was analyzed,and the temperature transfer matrix for general three-fluid separated heat exchanger working in parallel-flow or counter-flow mode was obtained.It was found that the forms of temperature transfer matrix are similar for heat pipe rows with equal or different heat transfer surface area.Furthermore,by using the temperature transfer matrix of the heat pipe exchanger,the relationship between heat transfer effectiveness θ 1,θ 2 and M,NTU,U,Δt i were derived for the exchanger operating in parallel-flow or counter-flow mode,and a simple special example was adopted to demonstrate the correctness of these relationships.
基金supported by the funding of the German Research Council (DFG), which, within the framework of its Excellence Initiative, supports the Cluster of Excellence “Engineering of Advanced Materials” (www.eam.uni-erlangen.de) at the University of Erlangen-Nürnberg
文摘The performance of an electrocatalyst, which is needed e.g. for key energy conversion reactions such as hydrogen evolution, oxygen reduction or CO2 reduction, is determined not only by the inherent structure of active sites but also by the properties of the interfacial structures at catalytic surfaces. Ionic liquids(ILs), as a unique class of metal salts with melting point below 100 ℃, present themselves as ideal modulators for manipulations of the interfacial structures. Due to their excellent properties such as good chemical stability, high ionic conductivity, wide electrochemical windows and tunable solvent properties the performance of electrocatalysts can be substantially improved through ILs. In the current minireview, we highlight the critical role of the IL phase at the microenvironments created by the IL, the liquid electrolyte, catalytic nanoparticles and/or support materials, by detailing the promotional effect of IL in electrocatalysis as reaction media, binders, and surface modifiers. Updated exemplary applications of IL in electrocatalysis are given and moreover, the latest developments of IL modified electrocatalysts following the "Solid Catalyst with Ionic Liquid Layer(SCILL)" concept are presented.
基金supported by the State Key Project of Fundamental Research of Ministry of Science and Technology,China(Grant No.2010CB934400)the National Natural Science Foundation of China(Grant Nos.51229101 and 11374351)
文摘Recent progresses in magnetic tunnel junctions with perpendicular magnetic anisotropy (PMA) are reviewed and summarized. At first, the concept and source of perpendicular magnetic anisotropy (PMA) are introduced. Next, a historical overview of PMA materials as magnetic electrodes, such as the RE-TM alloys TbFeCo and GdFeCo, novel tetragonal manganese alloys Mn-Ga, L10-ordered (Co, Fe)/Pt alloy, multilayer film [Co, Fe, CoFe/Pt, Pd, Ni, AU]N, and ultra-thin magnetic metal/oxidized barrier is offered. The other part of the article focuses on the optimization and fabrication of CoFeB/MgO/CoFeB p-MTJs, which is thought to have high potential to meet the main demands for non-volatile magnetic random access memory.
文摘In the process of bulk photopolymerization of styrene initiated by AIBN decomposition polyvinyl benzophenone (PVB) can supply an effective cage for triplet-triplet energy transfer between PVB macromolecules and small molecules of AIBN to influence the molecular weight of polystyrene in weak magnetic field (less than 0.035T), that was different from the case of polyvinyl naphthalene (PVN) which supplied cages for this system only in the stronger magnetic field (more than 0.2 T) studies. It was found that in the same conditions, PVN could exert more tremendous influences on the bulk photopolymerizatiou system of styrene than PVB because in the stronger magnetic field the triplet PVN had much longer life time than PVB.
基金supported by the National Natural Science Foundation of China(No.12001414)the Fundamental Research Funds for the Central Universities(No.JB210702)+4 种基金the open foundation of Hubei Key Laboratory of Theory and Application of Advanced Materials Mechanics(Wuhan University of Technology)(No.WUTTAM202104)the China Postdoctoral Science Foundation(No.2018M643573)the Natural Science Basic Research Program of Shaanxi Province(No.2019JQ-048)the National Natural Science Foundation of China(Nos.51739007 and 61971328)supported by the Center for high performance computing of Xidian University.
文摘In this paper,a novel mixed wavelet-learning method is developed for predicting macroscopic effective heat transfer conductivities of braided composite materials with heterogeneous thermal conductivity.This innovative methodology integrates respective superiorities of multi-scale modeling,wavelet transform and neural networks together.By the aid of asymptotic homogenization method(AHM),off-line multi-scalemodeling is accomplished for establishing thematerial databasewith highdimensional and highly-complexmappings.Themulti-scalematerial database and the wavelet-learning strategy ease the on-line training of neural networks,and enable us to efficiently build relatively simple networks that have an essentially increasing capacity and resisting noise for approximating the high-complexity mappings.Moreover,it should be emphasized that the wavelet-learning strategy can not only extract essential data characteristics from the material database,but also achieve a tremendous reduction in input data of neural networks.The numerical experiments performed using multiple 3D braided composite models verify the excellent performance of the presentedmixed approach.The numerical results demonstrate that themixedwaveletlearningmethodology is a robustmethod for computing themacroscopic effective heat transfer conductivities with distinct heterogeneity patterns.The presentedmethod can enormously decrease the computational time,and can be further expanded into estimating macroscopic effective mechanical properties of braided composites.