Natural gas hydrate in Class Ⅰ reservoirs holds significant commercial potential,as demonstrated by production trials in the South China Sea.However,experimental studies have focused largely on Class Ⅲ systems,with ...Natural gas hydrate in Class Ⅰ reservoirs holds significant commercial potential,as demonstrated by production trials in the South China Sea.However,experimental studies have focused largely on Class Ⅲ systems,with Class Ⅰ/Ⅱ reservoirs remaining underrepresented due to the difficulties in simulating the geothermal gradient and interlayer interactions.This study investigates depressurization performance across all three classes using a novel 360°rotatable reactor with segmented temperature control,enabling precise simulation of reservoir conditions.Results reveal:(i)Class Ⅰ shows two-stage gas production,with 50%from early free gas enabling rapid depressurization,followed by dissociated gas dominance.They achieve 38.4%-78.3%higher cumulative production and superior gas-to-water ratios due to efficient energy use.(ii)The free gas layer in Class Ⅰ accelerates pressure and heat transfer.Class Ⅱ’s water layer provides sensible heat but causes water blocking,impairing heat flow.Class Ⅲ exhibits rapid initial dissociation but a quick decline without fluid support.(iii)Low temperature,low hydrate saturation,and high production pressure collectively reduce efficiency by increasing flow resistance,limiting gas supply,and reducing dissociation drive.Over-depressurization risks hydrate reformation and ice blockage.This work bridges experimental gaps for Class Ⅰ/Ⅱ reservoirs,offering key insights for optimizing recovery.展开更多
This study discussed the application of response surface methodology(RSM)and central composite rotatable design(CCRD)for modeling and optimization of the influence of some operating variables on the performance of a l...This study discussed the application of response surface methodology(RSM)and central composite rotatable design(CCRD)for modeling and optimization of the influence of some operating variables on the performance of a lab scale thickener for dewatering of tailing in the flotation circuit.Four thickener operating variables,namely feed flowrate,solid percent,flocculant dosage and feedwell height were changed during the tests based on CCRD.The ranges of values of the thickener variables used in the design were a feed flowrate of 9–21 L/min,solid percent of 8%–20%,flocculant dosage of 1.25–4.25 g/t and feedwell height of 16–26 cm.A total of 30 thickening tests were conducted using lab scale thickener on flotation tailing obtained from the Sarcheshmeh copper mine,Iran.The underflow solid percent and bed height were expressed as functions of four operating parameters of thickener.Predicted values were found to be in good agreement with experimental values(R2values of 0.992 and 0.997 for underflow solid percent and bed height,respectively).This study has shown that the RSM and CCRD could effciently be applied for the modeling of thickener for dewatering of flotation tailing.展开更多
The dimpling defects caused by conventional hemispherical punch in doubly curved sheet metal reconfigurable die forming process were considered.The rotatable cubic punch (RCP) was developed to suppress the dimpling de...The dimpling defects caused by conventional hemispherical punch in doubly curved sheet metal reconfigurable die forming process were considered.The rotatable cubic punch (RCP) was developed to suppress the dimpling defects more effectively and conveniently.The former punch contacts with the work-piece through a point-surface contact and the latter punch contacts with the work-piece through a surface-surface contact.A series of stamping experiments were carried out using three different punches (hemispherical punch,RCP,chamfered-RCP) with three different loads.Some finite element simulations about the stamping experiments were carried out.The dimple scales were evaluated through the dimple depths.The corresponding data were obtained by 3-D scanning and FE result analysis respectively.A 3-D plate forming machine was developed,in which chamfered-RCP was adopted.Plate forming experiments were carried out on this machine.The stamped samples show a clear basis for the performance of chamfered-RCP.The study provided a means to guide the design of punches for dimpling suppression used in reconfigurable die.展开更多
Based on the symmetric re-entrant honeycomb(S-RH)structure with negative Poisson’s ratios,a novel asymmetric and rotatable re-entrant honeycomb(AR-RH)structure was proposed.Both the S-RH structure and AR-RH structure...Based on the symmetric re-entrant honeycomb(S-RH)structure with negative Poisson’s ratios,a novel asymmetric and rotatable re-entrant honeycomb(AR-RH)structure was proposed.Both the S-RH structure and AR-RH structure were produced by the 3D printing technology.Through experimental test and finite element simulation,the deformation mechanism and energy absorption characteristics of the AR-RH structure and the S-RH structure with negative Poisson’s ratios at different impact velocities were compared.The experimental test and finite element simulation results show that the novel AR-RH structure with negative Poisson’s ratios has stronger energy absorption capacity than the S-RH structure,and it has been verified that the rotatability of AR-RH can indeed absorb energy.Furthermore,the degree of asymmetry of the AR-RH structure was discussed.展开更多
The following article has been retracted due to the investigation of complaints received against it. Title: A New Method of Construction of Robust Second Order Rotatable Designs Using Balanced Incomplete Block Designs...The following article has been retracted due to the investigation of complaints received against it. Title: A New Method of Construction of Robust Second Order Rotatable Designs Using Balanced Incomplete Block Designs Authors: Bejjam Re. Victorbabu, Kottapalli Rajyalakshmi. The above paper is a copy of Dr. Rabindra Nath Das’s former article, entitled '“Robust second order rotatable designs (Part I)”. The scientific community takes a very strong view on this matter and we solemnly withdrawn?the paper from the journal OJS. This paper published in OJS Vol.2 No.1, 39-47, 2012, has been retracted.展开更多
Time-resolved Kerr rotation spectroscopy is used to determine the sign of the g factor of carriers in a semiconductor material, with the help of a rotatable magnetic field in the plane of the sample. The spin precessi...Time-resolved Kerr rotation spectroscopy is used to determine the sign of the g factor of carriers in a semiconductor material, with the help of a rotatable magnetic field in the plane of the sample. The spin precession signal of carriers at a fixed time delay is measured as a function of the orientation of the magnetic field with a fixed strength B. The signal has a sine-like form and its phase determines the sign of the g factor of carriers. As a natural extension of previous methods to measure the （time-resolved） photoluminescence or time-resolved Kerr rotation signal as a function of the magnetic field strength with a fixed orientation, such a method gives the correct sign of the g factor of electrons in GaAs. Furthermore, the sign of carriers in a （Ga, Mn）As magnetic semiconductor is also found to be negative.展开更多
We investigate the angular-dependent multi-mode resonance frequencies in CoZr magnetic thin films with a rotatable stripe domain structure.A variable range of multi-mode resonance frequencies from 1.86 GHz to 4.80 GHz...We investigate the angular-dependent multi-mode resonance frequencies in CoZr magnetic thin films with a rotatable stripe domain structure.A variable range of multi-mode resonance frequencies from 1.86 GHz to 4.80 GHz is achieved by pre-magnetizing the CoZr films along different azimuth directions,which can be ascribed to the competition between the uniaxial anisotropy caused by the oblique deposition and the rotatable anisotropy induced by the rotatable stripe domain.Furthermore,the regulating range of resonance frequency for the CoZr film can be adjusted by changing the oblique deposition angle.Our results might be beneficial for the applications of magnetic thin films in microwave devices.展开更多
The following article has been retracted due to the investigation of complaints received against it. Title: A New Method of Construction of Robust Second Order Slope Rotatable Designs Using Pairwise Balanced Designs. ...The following article has been retracted due to the investigation of complaints received against it. Title: A New Method of Construction of Robust Second Order Slope Rotatable Designs Using Pairwise Balanced Designs. Authors: Bejjam Re. Victorbabu, Kottapalli Rajyalakshmi.The paper is a copy of Dr. Rabindra Nath Das’s former article, entitled “Slope rotatability with correlated errors (Vol. 54, pp. 57-70, 2003)” and “Robust second order rotatable designs (Part I)”. The scientific community takes a very strong view on this matter and we treat all unethical behavior such as plagiarism seriously. This paper published in OJSVol.2 No.3, 319-327, 2012, has been removed from this site.展开更多
A valveless piezoelectric pump with rotatable unsymmetrical slopes is developed in this research.It has the following features:The pump integrates driving and transporting,and it can mix different fluids while transpo...A valveless piezoelectric pump with rotatable unsymmetrical slopes is developed in this research.It has the following features:The pump integrates driving and transporting,and it can mix different fluids while transporting them.In this paper,firstly,the design of the valveless piezoelectric pump with rotatable unsymmetrical slopes was proposed,and the single-direction flow principle was explained.Then,the fluid mechanics model of the valveless piezoelectric pump with rotatable unsymmetrical slopes was established.Meanwhile,the numerical simulation of the pump was performed.Finally,the experiments on relationship between the rotation angles of the slope and the flow rates were conducted.The experimental results showed that the maximum flow was 32.32 mL min 1.The maximum relative error between the theoretical results and the experimental ones was 14.59%.For the relationship between rotation angles and flow ratio of two inlets,the relative error between the experimental and theoretical maxima was 3.75%.Thus,the experiments proved the feasibility of the pump design and verified the theory.展开更多
The deformation behavior of GH4169 superalloy under room-temperature uniaxial tension was investigated through synchronized mesoscopic digital image correlation(DIC)and electron backscatter diffraction(EBSD)in-situ ch...The deformation behavior of GH4169 superalloy under room-temperature uniaxial tension was investigated through synchronized mesoscopic digital image correlation(DIC)and electron backscatter diffraction(EBSD)in-situ characterization techniques.Results show that in the field of grain deflection dynamics,through quantitative analysis using the independently developed M-DIC software,during uniaxial tension with significant bidirectional rotation along the tensile axis and the stress level of 1100 MPa,oscillatory rotation of±0.6°can be obtained,and microvoids are generated at the grain boundaries with 45°to the stress axis.EBSD crystallographic analysis demonstrates the load-dependent slip system evolution:in the initial stage,the soft-oriented systems with high Schmid factor(>0.4)is activated and then transformed into hard-oriented systems during cross-slip,generating parallel slip bands and dislocation pile-ups at grain boundaries.During the uniaxial tensile process,the characteristic of strain energy accumulation is observed,which follows a two-stage accumulation pattern:initial grain boundary localization(Stage I)and intragranular propagation(Stage II).Ultimately,the intergranular cracks are initiated at triple junctions,and the twin boundaries exhibit superior mechanical stability compared with the large-angle grain boundaries.Deformation texture characteristics indicate the copper-type components,including C{112}<111¯>,S{123}<634¯>,and B{110}<11¯0>.The complete deformation sequence is as follows:cross-slip of soft-oriented slip systems→initiation of dislocation slip→strain partitioning through grain rotation→intergranular stress concentration→damage dominated by boundary cracking.The cross-scale deformation mechanism revealed in this study provides critical guidance for the crystal boundary engineering to optimize nickel-based superalloys.展开更多
Rotatability is a desirable quality of fitting response surface experimental designs. The propertystates that the variance of the estimated response made from the Taylor’s series expansion areconstant on circles, sph...Rotatability is a desirable quality of fitting response surface experimental designs. The propertystates that the variance of the estimated response made from the Taylor’s series expansion areconstant on circles, spheres and hyper-spheres about the centre of the design. In this article,a measure of rotatability of modified second-order rotatable design is presented. The variancefunction of a second-order response design and an infinite class of supplementary difference setsis used in coming up with the design.展开更多
The technique of fitting a response surface design is useful in modelling of experimental designs.Response surface is used in situations where the response of interest is influenced by several experimental variables.T...The technique of fitting a response surface design is useful in modelling of experimental designs.Response surface is used in situations where the response of interest is influenced by several experimental variables.The objective of fitting a response surface design is to reduce cost of experimentation and to obtain optimal designs.The property of rotatability is a desirable quantity of experimental design and requires the variance of the fitted design to be constant on circles or spheres about the centre of the design.In this article,a construction technique of fitting modified non-sequential third order rotatable design(TORD)using Pairwise Balanced Design(PBD)is presented.The variance function of a third order response surface design and the properties of Pairwise Balanced Design are utilised for the construction.展开更多
We propose a novel cooling protocol within a triple-Laguerre-Gaussian cavity optomechanical system,which is designed to suppress the thermal vibrations of a rotating mirror to reach its quantum ground state.The system...We propose a novel cooling protocol within a triple-Laguerre-Gaussian cavity optomechanical system,which is designed to suppress the thermal vibrations of a rotating mirror to reach its quantum ground state.The system incorporates two auxiliary cavities and an atomic ensemble coupled to a Laguerre-Gaussian rotational cavity.By carefully selecting system parameters,the cooling process of the rotating mirror is significantly enhanced,while the heating process is effectively suppressed,enabling efficient ground-state cooling even in the unresolved sideband regime.Compared to previous works,our scheme reduces the stringent restrictions on auxiliary systems,making it more experimentally feasible under broader parameter conditions.These findings provide a robust approach for achieving ground-state cooling in mechanical resonators.展开更多
We demonstrate a high-speed rotating slit beam shaping method for femtosecond(fs)laser three-dimensional(3D)isotropic inscription in glass materials.By integrating fs laser direct writing with a real-time rotating sli...We demonstrate a high-speed rotating slit beam shaping method for femtosecond(fs)laser three-dimensional(3D)isotropic inscription in glass materials.By integrating fs laser direct writing with a real-time rotating slit mechanism,a 3D symmetric spherical focal field distribution is created in the laser-irradiated regions of transparent substrates.The corresponding focal field distribution is theoretically calculated and validated by examining the features of laser-inscribed lines in glass samples.Moreover,we investigate the influences of laser writing speed and slit rotational speed on the fabrication resolution in glass,and discuss the formation mechanism of the generated periodic microstructures.To showcase its powerful capability for3D isotropic fabrication,the high-speed rotating slit beam shaping method is applied to create straight optical waveguides,bending optical waveguides,and hollow microchannels in the glass.The proposed method holds great potential for the facile manufacture of diverse 3D isotropic microstructures and devices within transparent materials across various applications,including advanced photonics,microoptics,micro-electromechanical systems,and microfluidics.展开更多
Irreversible fibrotic scarring after rotator cuff tear(RCT)compromises the mechanical properties of the healing tendon,yet the underlying mechanisms remain poorly understood.Here,we analyzed the histological features ...Irreversible fibrotic scarring after rotator cuff tear(RCT)compromises the mechanical properties of the healing tendon,yet the underlying mechanisms remain poorly understood.Here,we analyzed the histological features of human RCT scars,characterized by disruption of tendon architecture,disorganized collagen fibrils,and imbalance in type Ⅰ/Ⅲ collagen ratios and fibril diameters.Using single-cell RNA sequencing of tendon stumps from patients with RCT,we deconvolved the cellular and molecular landscape of the fibrotic scarring microenvironment.Heterogenous pro-fibrotic subclusters were identified and validated to participate into scar formation,including tendon stem cell,senescent tenocyte,SOX9-driven pro-fibrotic macrophage,and pro-fibrotic endothelial cells undergoing endothelial-mesenchymal transition(EndoMT).Furthermore,we found that osteopontin and TGF-βsignaling were key drivers of extracellular matrix deposition,and their blockade ameliorated fibrotic scarring after RCT.Collectively,our study dissected the dynamic scarring microenvironment in human RCT and highlights potential therapeutic targets for preventing pathological scar formation.展开更多
This study investigates the impact of Type D additive,Plastiment 83 AM,on the compressive strength and microstructure of Portland Composite Cement(PCC)concrete with a target compressive strength of 18.7 MPa,utilizing ...This study investigates the impact of Type D additive,Plastiment 83 AM,on the compressive strength and microstructure of Portland Composite Cement(PCC)concrete with a target compressive strength of 18.7 MPa,utilizing a mixing,stirring,and treatment model that simulates batching plant conditions.The study investigated additive dosages of 0%,0.15%,0.25%,0.35%,and 0.40%,with stirring durations of 15 min,2,4,6,and 6.5 h.Compressive strength tests were conducted at the ages of 7,14,28,56,and 90 days on cylindrical specimens,and at 24 h for setting time tests.Microstructural analysis using Energy Dispersive X-ray Spectroscopy(EDX)was performed at 56 days of age.The results showed that the optimal dosage was 0.15%,combined with the addition of Plastiment 83 AM 0.10%at 2 h of stirring,which achieved the highest compressive strength of 20.5 MPa at 90 days.A reduction in compressive strength of the setting time samples from the initial value to 24 h was observed in mixtures stirred for 6 and 6.5 h.A decrease in compressive strength was also observed in both mixtures between 56 and 90 days.EDX analysis revealed different chemical compositions in each mix.At a stirring duration of 6 and 6.5 h,Plastiment 83 AM dosages of 0.35%and 0.40%showed the presence of Magnesium(Mg)and Aluminium(Al)(at 6 h)and Al and phosphorus(at 6.5 h).The presence of inhibited the hydration process,resulting in a very small increase in compressive strength from 14 to 28 days.Magnesium reduced the compressive strength to 75%,and phosphorus to 63%of the target compressive strength.展开更多
Objectives:One of the most notable challenges in endoscopic procedures is maintaining correct orientation.Mental rotation exercise(MRE)has been suggested as a potential aid for improving orientation.However,there is a...Objectives:One of the most notable challenges in endoscopic procedures is maintaining correct orientation.Mental rotation exercise(MRE)has been suggested as a potential aid for improving orientation.However,there is a lack of research on designing MREs with varying difficultylevels for training purposes.Furthermore,few studies provide solid evidence linking MRE difficultylevels with cognitive load measurements.This study aims to address this gap by investigating the correlation between the MRE difficultylevels and participants’cognitive load,as measured by pupil dilation.Method:We recruited 33 participants to perform MREs on a computer equipped with a screen-mounted eye-tracker.The test consisted of 15 MREs,with the first10 relatively easy(traditional cube)and the next 5 more complex(invented molecule).The participants’eye movements during MREs were recorded.The participants’MRE scores and pupil dilation were obtained and compared between two MRE difficultylevels.Results:The participants who performed traditional cube MREs achieved significantlybetter MRE scores(0.77±0.11 vs.0.58±0.03,p<0.001)and lower pupil dilation(0.27±0.04 pixels vs.0.47±0.09 pixels,p<0.001)than did those who performed the invented molecule MREs.Moreover,there were significant negative correlations(r=0.62,p=0.015)between pupil dilation and MRE scores.Conclusions:The results revealed a significantnegative correlation between MRE scores and pupil dilation.The more challenging MRE questions led to worse MRE scores but increased pupil dilation.The MRE difficultylevels can be evaluated not only by the degrees or dimensions with which the objects were rotated but also by the participants’MRE scores and pupil dilation.The results of this study provide a basis for training orientation skills in endoscopy using MREs.By incorporating MREs with varying difficultylevels,customized training programs can be developed to enhance camera navigation in endoscopic and laparoscopic procedures.展开更多
As a type of emerging electro-mechanical conversion technology,triboelectric nanogenerators(TENGs)were widely applied in high-entropy energy harvesting,Internet of Things sensing,and biomedical fields due to the chara...As a type of emerging electro-mechanical conversion technology,triboelectric nanogenerators(TENGs)were widely applied in high-entropy energy harvesting,Internet of Things sensing,and biomedical fields due to the characteristics of lightweight,cheap,and high voltage.Among them,the rotating TENG has been extensively researched for its advantages,such as high-precision electrical signals,high electro-mechanical conversion efficiency,and effective output power.In this paper,the working mechanisms of four different rotating TENG modes were introduced in detail.Subsequently,a large amount of research works on the strengthening performance of rotating TENGs were comprehensively introduced and summarized by three gradient classifications.In addition,in view of the many applications of rotating TENGs,they were also systematically divided and generalized into three dimensions.Finally,the problems as well as challenges faced by the current rotating TENG research in the above 16 specific research directions were deeply analyzed,and the possible development directions and the solutions to the above problems were reasonably prospected in the next years.This review hopes to effectively promote the progress of rotating TENG on the road to commercialization.展开更多
In this paper,a theoretical model is established for locally resonant plates with general resonators,and the corresponding governing equation is derived.The model provides a mathematical demonstration of the locally r...In this paper,a theoretical model is established for locally resonant plates with general resonators,and the corresponding governing equation is derived.The model provides a mathematical demonstration of the locally resonant effect,which contains two parts:the first part is induced by translation coupling,and the second part is induced by rotation coupling.The second part cannot be reflected by most existing theoretical models.The analytical solutions of the dynamic response are compared with the direct numerical simulation(DNS)results for two locally resonant plates with different resonator types,thereby validating the general applicability of the present model.The rotation coupling effect leads to the frequency-dependent effective rotational inertia density and anisotropic dispersion relation of the locally resonant plate,as well as the enhancement of the structural vibration suppression ability.展开更多
基金partially funded by Shenzhen Science and Technology Program(No.JCYJ20240813112038050)the National Natural Science Foundation of China(No.52404059)+1 种基金the Economy Trade and Information Commission of Shenzhen Municipality,China(No.HYCYPT20140507010002)the Key Program of Marine Economy Development(Six Marine Industries)Special Foundation of the Department of Natural Resources of Guangdong Province,China(No.GDOE[2021]55).
文摘Natural gas hydrate in Class Ⅰ reservoirs holds significant commercial potential,as demonstrated by production trials in the South China Sea.However,experimental studies have focused largely on Class Ⅲ systems,with Class Ⅰ/Ⅱ reservoirs remaining underrepresented due to the difficulties in simulating the geothermal gradient and interlayer interactions.This study investigates depressurization performance across all three classes using a novel 360°rotatable reactor with segmented temperature control,enabling precise simulation of reservoir conditions.Results reveal:(i)Class Ⅰ shows two-stage gas production,with 50%from early free gas enabling rapid depressurization,followed by dissociated gas dominance.They achieve 38.4%-78.3%higher cumulative production and superior gas-to-water ratios due to efficient energy use.(ii)The free gas layer in Class Ⅰ accelerates pressure and heat transfer.Class Ⅱ’s water layer provides sensible heat but causes water blocking,impairing heat flow.Class Ⅲ exhibits rapid initial dissociation but a quick decline without fluid support.(iii)Low temperature,low hydrate saturation,and high production pressure collectively reduce efficiency by increasing flow resistance,limiting gas supply,and reducing dissociation drive.Over-depressurization risks hydrate reformation and ice blockage.This work bridges experimental gaps for Class Ⅰ/Ⅱ reservoirs,offering key insights for optimizing recovery.
基金supported by the National Iranian Copper Industry Co.
文摘This study discussed the application of response surface methodology(RSM)and central composite rotatable design(CCRD)for modeling and optimization of the influence of some operating variables on the performance of a lab scale thickener for dewatering of tailing in the flotation circuit.Four thickener operating variables,namely feed flowrate,solid percent,flocculant dosage and feedwell height were changed during the tests based on CCRD.The ranges of values of the thickener variables used in the design were a feed flowrate of 9–21 L/min,solid percent of 8%–20%,flocculant dosage of 1.25–4.25 g/t and feedwell height of 16–26 cm.A total of 30 thickening tests were conducted using lab scale thickener on flotation tailing obtained from the Sarcheshmeh copper mine,Iran.The underflow solid percent and bed height were expressed as functions of four operating parameters of thickener.Predicted values were found to be in good agreement with experimental values(R2values of 0.992 and 0.997 for underflow solid percent and bed height,respectively).This study has shown that the RSM and CCRD could effciently be applied for the modeling of thickener for dewatering of flotation tailing.
基金the National Natural Science Foundation of China(Nos.51379167 and 51779200)。
文摘The dimpling defects caused by conventional hemispherical punch in doubly curved sheet metal reconfigurable die forming process were considered.The rotatable cubic punch (RCP) was developed to suppress the dimpling defects more effectively and conveniently.The former punch contacts with the work-piece through a point-surface contact and the latter punch contacts with the work-piece through a surface-surface contact.A series of stamping experiments were carried out using three different punches (hemispherical punch,RCP,chamfered-RCP) with three different loads.Some finite element simulations about the stamping experiments were carried out.The dimple scales were evaluated through the dimple depths.The corresponding data were obtained by 3-D scanning and FE result analysis respectively.A 3-D plate forming machine was developed,in which chamfered-RCP was adopted.Plate forming experiments were carried out on this machine.The stamped samples show a clear basis for the performance of chamfered-RCP.The study provided a means to guide the design of punches for dimpling suppression used in reconfigurable die.
基金This work is supported by the State Key for Strength and Vibration of Mechanical Structures of Xi’an Jiaotong University(No.SV2018-KF-32)the Natural Science Foundation of Guangdong Province of China(2020A1515011064).
文摘Based on the symmetric re-entrant honeycomb(S-RH)structure with negative Poisson’s ratios,a novel asymmetric and rotatable re-entrant honeycomb(AR-RH)structure was proposed.Both the S-RH structure and AR-RH structure were produced by the 3D printing technology.Through experimental test and finite element simulation,the deformation mechanism and energy absorption characteristics of the AR-RH structure and the S-RH structure with negative Poisson’s ratios at different impact velocities were compared.The experimental test and finite element simulation results show that the novel AR-RH structure with negative Poisson’s ratios has stronger energy absorption capacity than the S-RH structure,and it has been verified that the rotatability of AR-RH can indeed absorb energy.Furthermore,the degree of asymmetry of the AR-RH structure was discussed.
文摘The following article has been retracted due to the investigation of complaints received against it. Title: A New Method of Construction of Robust Second Order Rotatable Designs Using Balanced Incomplete Block Designs Authors: Bejjam Re. Victorbabu, Kottapalli Rajyalakshmi. The above paper is a copy of Dr. Rabindra Nath Das’s former article, entitled '“Robust second order rotatable designs (Part I)”. The scientific community takes a very strong view on this matter and we solemnly withdrawn?the paper from the journal OJS. This paper published in OJS Vol.2 No.1, 39-47, 2012, has been retracted.
基金Project supported by the National Basic Research Program of China (Grant No. 2009CB929301)the National Natural Science Foundation of China (Grant No. 10911130232)
文摘Time-resolved Kerr rotation spectroscopy is used to determine the sign of the g factor of carriers in a semiconductor material, with the help of a rotatable magnetic field in the plane of the sample. The spin precession signal of carriers at a fixed time delay is measured as a function of the orientation of the magnetic field with a fixed strength B. The signal has a sine-like form and its phase determines the sign of the g factor of carriers. As a natural extension of previous methods to measure the （time-resolved） photoluminescence or time-resolved Kerr rotation signal as a function of the magnetic field strength with a fixed orientation, such a method gives the correct sign of the g factor of electrons in GaAs. Furthermore, the sign of carriers in a （Ga, Mn）As magnetic semiconductor is also found to be negative.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51871117 and 51671099)the Program for Changjiang Scholars and Innovative Research Team in University,China(Grant No.IRT-16R35)the Gansu Provincial Science Foundation for Distinguished Young Scholars,China(Grant No.20JR10RA649).
文摘We investigate the angular-dependent multi-mode resonance frequencies in CoZr magnetic thin films with a rotatable stripe domain structure.A variable range of multi-mode resonance frequencies from 1.86 GHz to 4.80 GHz is achieved by pre-magnetizing the CoZr films along different azimuth directions,which can be ascribed to the competition between the uniaxial anisotropy caused by the oblique deposition and the rotatable anisotropy induced by the rotatable stripe domain.Furthermore,the regulating range of resonance frequency for the CoZr film can be adjusted by changing the oblique deposition angle.Our results might be beneficial for the applications of magnetic thin films in microwave devices.
文摘The following article has been retracted due to the investigation of complaints received against it. Title: A New Method of Construction of Robust Second Order Slope Rotatable Designs Using Pairwise Balanced Designs. Authors: Bejjam Re. Victorbabu, Kottapalli Rajyalakshmi.The paper is a copy of Dr. Rabindra Nath Das’s former article, entitled “Slope rotatability with correlated errors (Vol. 54, pp. 57-70, 2003)” and “Robust second order rotatable designs (Part I)”. The scientific community takes a very strong view on this matter and we treat all unethical behavior such as plagiarism seriously. This paper published in OJSVol.2 No.3, 319-327, 2012, has been removed from this site.
基金supported by the National Natural Science Foundation of China (Grant Nos. 50775109 and 51075201)the Important Projects of National Science Foundation of China (Grant No. 50735002)Open Fund of State Key Lab of Digital Manufacturing Equipment and Technology (Grant No. DMETKF2009002)
文摘A valveless piezoelectric pump with rotatable unsymmetrical slopes is developed in this research.It has the following features:The pump integrates driving and transporting,and it can mix different fluids while transporting them.In this paper,firstly,the design of the valveless piezoelectric pump with rotatable unsymmetrical slopes was proposed,and the single-direction flow principle was explained.Then,the fluid mechanics model of the valveless piezoelectric pump with rotatable unsymmetrical slopes was established.Meanwhile,the numerical simulation of the pump was performed.Finally,the experiments on relationship between the rotation angles of the slope and the flow rates were conducted.The experimental results showed that the maximum flow was 32.32 mL min 1.The maximum relative error between the theoretical results and the experimental ones was 14.59%.For the relationship between rotation angles and flow ratio of two inlets,the relative error between the experimental and theoretical maxima was 3.75%.Thus,the experiments proved the feasibility of the pump design and verified the theory.
基金National Natural Science Foundation of China(2022YFF0609300)。
文摘The deformation behavior of GH4169 superalloy under room-temperature uniaxial tension was investigated through synchronized mesoscopic digital image correlation(DIC)and electron backscatter diffraction(EBSD)in-situ characterization techniques.Results show that in the field of grain deflection dynamics,through quantitative analysis using the independently developed M-DIC software,during uniaxial tension with significant bidirectional rotation along the tensile axis and the stress level of 1100 MPa,oscillatory rotation of±0.6°can be obtained,and microvoids are generated at the grain boundaries with 45°to the stress axis.EBSD crystallographic analysis demonstrates the load-dependent slip system evolution:in the initial stage,the soft-oriented systems with high Schmid factor(>0.4)is activated and then transformed into hard-oriented systems during cross-slip,generating parallel slip bands and dislocation pile-ups at grain boundaries.During the uniaxial tensile process,the characteristic of strain energy accumulation is observed,which follows a two-stage accumulation pattern:initial grain boundary localization(Stage I)and intragranular propagation(Stage II).Ultimately,the intergranular cracks are initiated at triple junctions,and the twin boundaries exhibit superior mechanical stability compared with the large-angle grain boundaries.Deformation texture characteristics indicate the copper-type components,including C{112}<111¯>,S{123}<634¯>,and B{110}<11¯0>.The complete deformation sequence is as follows:cross-slip of soft-oriented slip systems→initiation of dislocation slip→strain partitioning through grain rotation→intergranular stress concentration→damage dominated by boundary cracking.The cross-scale deformation mechanism revealed in this study provides critical guidance for the crystal boundary engineering to optimize nickel-based superalloys.
文摘Rotatability is a desirable quality of fitting response surface experimental designs. The propertystates that the variance of the estimated response made from the Taylor’s series expansion areconstant on circles, spheres and hyper-spheres about the centre of the design. In this article,a measure of rotatability of modified second-order rotatable design is presented. The variancefunction of a second-order response design and an infinite class of supplementary difference setsis used in coming up with the design.
文摘The technique of fitting a response surface design is useful in modelling of experimental designs.Response surface is used in situations where the response of interest is influenced by several experimental variables.The objective of fitting a response surface design is to reduce cost of experimentation and to obtain optimal designs.The property of rotatability is a desirable quantity of experimental design and requires the variance of the fitted design to be constant on circles or spheres about the centre of the design.In this article,a construction technique of fitting modified non-sequential third order rotatable design(TORD)using Pairwise Balanced Design(PBD)is presented.The variance function of a third order response surface design and the properties of Pairwise Balanced Design are utilised for the construction.
基金Project supported by the National Natural Science Foundation of China(Grant No.62471180)。
文摘We propose a novel cooling protocol within a triple-Laguerre-Gaussian cavity optomechanical system,which is designed to suppress the thermal vibrations of a rotating mirror to reach its quantum ground state.The system incorporates two auxiliary cavities and an atomic ensemble coupled to a Laguerre-Gaussian rotational cavity.By carefully selecting system parameters,the cooling process of the rotating mirror is significantly enhanced,while the heating process is effectively suppressed,enabling efficient ground-state cooling even in the unresolved sideband regime.Compared to previous works,our scheme reduces the stringent restrictions on auxiliary systems,making it more experimentally feasible under broader parameter conditions.These findings provide a robust approach for achieving ground-state cooling in mechanical resonators.
基金supported by the National Key Research and Development Program of China(2022YFA1404800)National Natural Science Foundation of China(12174107,12004221,12192254,92250304,W2441005,12334014,12192251)+4 种基金Natural Science Foundation of Shandong Province(ZR2024QA024,ZR2021ZD02)Postdoctoral Innovation Talents Support Program of Shandong Province(No.SDBX2019005)Shanghai Municipal Science and Technology Major ProjectFundamental Research Funds for the Central UniversitiesEngineering Research Center for Nanophotonics&Advanced Instrument,Ministry of Education,East China Normal University(No.2023nmc005)。
文摘We demonstrate a high-speed rotating slit beam shaping method for femtosecond(fs)laser three-dimensional(3D)isotropic inscription in glass materials.By integrating fs laser direct writing with a real-time rotating slit mechanism,a 3D symmetric spherical focal field distribution is created in the laser-irradiated regions of transparent substrates.The corresponding focal field distribution is theoretically calculated and validated by examining the features of laser-inscribed lines in glass samples.Moreover,we investigate the influences of laser writing speed and slit rotational speed on the fabrication resolution in glass,and discuss the formation mechanism of the generated periodic microstructures.To showcase its powerful capability for3D isotropic fabrication,the high-speed rotating slit beam shaping method is applied to create straight optical waveguides,bending optical waveguides,and hollow microchannels in the glass.The proposed method holds great potential for the facile manufacture of diverse 3D isotropic microstructures and devices within transparent materials across various applications,including advanced photonics,microoptics,micro-electromechanical systems,and microfluidics.
基金supported by the National Natural Science Foundation of China(NO.82230085,82272572,82030071)National Key Research and Development Program of China(NO.2022YFC2010204)Natural Science Foundation of Hunan Province(NO.2024JJ6637)。
文摘Irreversible fibrotic scarring after rotator cuff tear(RCT)compromises the mechanical properties of the healing tendon,yet the underlying mechanisms remain poorly understood.Here,we analyzed the histological features of human RCT scars,characterized by disruption of tendon architecture,disorganized collagen fibrils,and imbalance in type Ⅰ/Ⅲ collagen ratios and fibril diameters.Using single-cell RNA sequencing of tendon stumps from patients with RCT,we deconvolved the cellular and molecular landscape of the fibrotic scarring microenvironment.Heterogenous pro-fibrotic subclusters were identified and validated to participate into scar formation,including tendon stem cell,senescent tenocyte,SOX9-driven pro-fibrotic macrophage,and pro-fibrotic endothelial cells undergoing endothelial-mesenchymal transition(EndoMT).Furthermore,we found that osteopontin and TGF-βsignaling were key drivers of extracellular matrix deposition,and their blockade ameliorated fibrotic scarring after RCT.Collectively,our study dissected the dynamic scarring microenvironment in human RCT and highlights potential therapeutic targets for preventing pathological scar formation.
文摘This study investigates the impact of Type D additive,Plastiment 83 AM,on the compressive strength and microstructure of Portland Composite Cement(PCC)concrete with a target compressive strength of 18.7 MPa,utilizing a mixing,stirring,and treatment model that simulates batching plant conditions.The study investigated additive dosages of 0%,0.15%,0.25%,0.35%,and 0.40%,with stirring durations of 15 min,2,4,6,and 6.5 h.Compressive strength tests were conducted at the ages of 7,14,28,56,and 90 days on cylindrical specimens,and at 24 h for setting time tests.Microstructural analysis using Energy Dispersive X-ray Spectroscopy(EDX)was performed at 56 days of age.The results showed that the optimal dosage was 0.15%,combined with the addition of Plastiment 83 AM 0.10%at 2 h of stirring,which achieved the highest compressive strength of 20.5 MPa at 90 days.A reduction in compressive strength of the setting time samples from the initial value to 24 h was observed in mixtures stirred for 6 and 6.5 h.A decrease in compressive strength was also observed in both mixtures between 56 and 90 days.EDX analysis revealed different chemical compositions in each mix.At a stirring duration of 6 and 6.5 h,Plastiment 83 AM dosages of 0.35%and 0.40%showed the presence of Magnesium(Mg)and Aluminium(Al)(at 6 h)and Al and phosphorus(at 6.5 h).The presence of inhibited the hydration process,resulting in a very small increase in compressive strength from 14 to 28 days.Magnesium reduced the compressive strength to 75%,and phosphorus to 63%of the target compressive strength.
文摘Objectives:One of the most notable challenges in endoscopic procedures is maintaining correct orientation.Mental rotation exercise(MRE)has been suggested as a potential aid for improving orientation.However,there is a lack of research on designing MREs with varying difficultylevels for training purposes.Furthermore,few studies provide solid evidence linking MRE difficultylevels with cognitive load measurements.This study aims to address this gap by investigating the correlation between the MRE difficultylevels and participants’cognitive load,as measured by pupil dilation.Method:We recruited 33 participants to perform MREs on a computer equipped with a screen-mounted eye-tracker.The test consisted of 15 MREs,with the first10 relatively easy(traditional cube)and the next 5 more complex(invented molecule).The participants’eye movements during MREs were recorded.The participants’MRE scores and pupil dilation were obtained and compared between two MRE difficultylevels.Results:The participants who performed traditional cube MREs achieved significantlybetter MRE scores(0.77±0.11 vs.0.58±0.03,p<0.001)and lower pupil dilation(0.27±0.04 pixels vs.0.47±0.09 pixels,p<0.001)than did those who performed the invented molecule MREs.Moreover,there were significant negative correlations(r=0.62,p=0.015)between pupil dilation and MRE scores.Conclusions:The results revealed a significantnegative correlation between MRE scores and pupil dilation.The more challenging MRE questions led to worse MRE scores but increased pupil dilation.The MRE difficultylevels can be evaluated not only by the degrees or dimensions with which the objects were rotated but also by the participants’MRE scores and pupil dilation.The results of this study provide a basis for training orientation skills in endoscopy using MREs.By incorporating MREs with varying difficultylevels,customized training programs can be developed to enhance camera navigation in endoscopic and laparoscopic procedures.
基金supported by the China National Postdoctoral Program for Innovative Talents(BX20230037)Talent Fund of Beijing Jiaotong University(2023XKRC034)+1 种基金China Postdoctoral Science Foundation(2023M730205)China Scholarship Council(202407090030)。
文摘As a type of emerging electro-mechanical conversion technology,triboelectric nanogenerators(TENGs)were widely applied in high-entropy energy harvesting,Internet of Things sensing,and biomedical fields due to the characteristics of lightweight,cheap,and high voltage.Among them,the rotating TENG has been extensively researched for its advantages,such as high-precision electrical signals,high electro-mechanical conversion efficiency,and effective output power.In this paper,the working mechanisms of four different rotating TENG modes were introduced in detail.Subsequently,a large amount of research works on the strengthening performance of rotating TENGs were comprehensively introduced and summarized by three gradient classifications.In addition,in view of the many applications of rotating TENGs,they were also systematically divided and generalized into three dimensions.Finally,the problems as well as challenges faced by the current rotating TENG research in the above 16 specific research directions were deeply analyzed,and the possible development directions and the solutions to the above problems were reasonably prospected in the next years.This review hopes to effectively promote the progress of rotating TENG on the road to commercialization.
基金Project supported by the National Natural Science Foundation of China(No.12472062)。
文摘In this paper,a theoretical model is established for locally resonant plates with general resonators,and the corresponding governing equation is derived.The model provides a mathematical demonstration of the locally resonant effect,which contains two parts:the first part is induced by translation coupling,and the second part is induced by rotation coupling.The second part cannot be reflected by most existing theoretical models.The analytical solutions of the dynamic response are compared with the direct numerical simulation(DNS)results for two locally resonant plates with different resonator types,thereby validating the general applicability of the present model.The rotation coupling effect leads to the frequency-dependent effective rotational inertia density and anisotropic dispersion relation of the locally resonant plate,as well as the enhancement of the structural vibration suppression ability.
