Nowadays,there is a growing global demand for high-performance room temperature gas sensing de-vices.In this context,we aim to explore the advancements in two-dimensional(2D)Ti_(3)C_(2)MXene role for toxic NO_(2)gas s...Nowadays,there is a growing global demand for high-performance room temperature gas sensing de-vices.In this context,we aim to explore the advancements in two-dimensional(2D)Ti_(3)C_(2)MXene role for toxic NO_(2)gas sensing at room temperature.The distinctive advantages of 2D Ti_(3)C_(2)MXene,including high electrical conductivity,ample surface area,surface termination groups,and layer structure have garnered significant attention towards NO_(2)gas adsorption.Further,the compatible regularity of Ti_(3)C_(2)MXene at the interface of various semiconductors directed the development of potential room-temperature NO_(2)gas sensing devices.Further,the leveraging gas sensing(selectivity,response,and recovery)characteristics be-come increasing attention on Ti_(3)C_(2)MXene/semiconductor interfaces than pure Ti_(3)C_(2)MXene.Elaborative control on the depletion layer through the Schottky barrier formation distinguished the room tempera-ture NO_(2)gas sensing and led to the evolution of electrophilic NO_(2)gas molecule interaction.Remarkably,the great processability of Ti_(3)C_(2)MXene/semiconductor interface is sensitive to the low detection limit(LOD)of NO_(2)gas at parts per billion(ppb)conditions.On the other hand,this review demonstrates the room temperature optoelectronic NO_(2)gas sensing capabilities of Ti_(3)C_(2)-based composites for emphasiz-ing selectivity and recovery.Interestingly,the Ti_(3)C_(2)MXene/semiconductor composite builds immunity against the atmosphere humidity and achieves stable NO_(2)gas sensing.Finally,we have provided conclu-sions and key points to advance the research on room temperature NO_(2)gas sensing of Ti_(3)C_(2)integrated semiconductors.展开更多
With respect to oceanic fluid dynamics,certain models have appeared,e.g.,an extended time-dependent(3+1)-dimensional shallow water wave equation in an ocean or a river,which we investigate in this paper.Using symbolic...With respect to oceanic fluid dynamics,certain models have appeared,e.g.,an extended time-dependent(3+1)-dimensional shallow water wave equation in an ocean or a river,which we investigate in this paper.Using symbolic computation,we find out,on one hand,a set of bilinear auto-Backlund transformations,which could connect certain solutions of that equation with other solutions of that equation itself,and on the other hand,a set of similarity reductions,which could go from that equation to a known ordinary differential equation.The results in this paper depend on all the oceanic variable coefficients in that equation.展开更多
This paper proposes a novel cargo loading algorithm applicable to automated conveyor-type loading systems.The algorithm offers improvements in computational efficiency and robustness by utilizing the concept of discre...This paper proposes a novel cargo loading algorithm applicable to automated conveyor-type loading systems.The algorithm offers improvements in computational efficiency and robustness by utilizing the concept of discrete derivatives and introducing logistics-related constraints.Optional consideration of the rotation of the cargoes was made to further enhance the optimality of the solutions,if possible to be physically implemented.Evaluation metrics were developed for accurate evaluation and enhancement of the algorithm’s ability to efficiently utilize the loading space and provide a high level of dynamic stability.Experimental results demonstrate the extensive robustness of the proposed algorithm to the diversity of cargoes present in Business-to-Consumer environments.This study contributes practical advancements in both cargo loading optimization and automation of the logistics industry,with potential applications in last-mile delivery services,warehousing,and supply chain management.展开更多
Lie symmetry analysis is applied to a(3+1)-dimensional combined potential Kadomtsev-Petviashvili equation with B-type Kadomtsev-Petviashvili equation(pKP-BKP equation)and the corresponding similarity reduction equatio...Lie symmetry analysis is applied to a(3+1)-dimensional combined potential Kadomtsev-Petviashvili equation with B-type Kadomtsev-Petviashvili equation(pKP-BKP equation)and the corresponding similarity reduction equations are obtained with the different infinitesimal generators.Invariant solutions with arbitrary functions and constants for the(3+1)-dimensional pKP-BKP equation,including the lump solution,the periodic-lump solution,the two-kink solution,the breather solution and the lump-two-kink solution,have been studied analytically and graphically.展开更多
In this article,a Generalized Calogero-Bogoyavlenskii-Schiff(CBS)equation is studied,serving as an extended shallow water wave model in higher dimensions.Firstly,utilizing the Bell polynomial method,the bilinear form ...In this article,a Generalized Calogero-Bogoyavlenskii-Schiff(CBS)equation is studied,serving as an extended shallow water wave model in higher dimensions.Firstly,utilizing the Bell polynomial method,the bilinear form of the equation,bilinear Bäcklund transformation,Lax pair and infinite conservation laws are derived,confirming the equation’s complete integrability in the context of the Lax pair.Subsequently,the nonlinear superposition formula of the equation is constructed based on the derived bilinear Bäcklund transformation and an array of infinite superposition soliton solutions of the equation are formulated using this nonlinear superposition formula.Lastly,leveraging the obtained bilinear equation,infinite superposition solutions of various functional types are constructed.Their dynamic characteristics are analyzed through illustrated solution images.It is noteworthy that this paper not only uncovers a multitude of properties through the Bell polynomial method but also derives both infinite linear and nonlinear superposition solutions,enriching the diversity of solutions,these aspects have not been previously explored in existing literature.展开更多
A set of germanate garnet phosphors containing Tb^(3+)and Eu^(3+)were adequately synthesized using the high-temperature solid-state technique.The structural properties,photoluminescence characteristics,fluorescence li...A set of germanate garnet phosphors containing Tb^(3+)and Eu^(3+)were adequately synthesized using the high-temperature solid-state technique.The structural properties,photoluminescence characteristics,fluorescence lifetimes,and temperature-sensing capabilities of the phosphors were thoroughly investigated.X-ray diffraction confirms the crystalline structure of the phosphors,while photoluminescence spectra reveal a colour shift attributed to the trans fer of energy from Tb^(3+)to Eu^(3+)as the concentration of Eu^(3+)increases.The phosphors excited by UV light display a transition in colour from green to yellow,and subsequently to red,which can be used as a colour tunable phosphor in white light-emitting diode(w-LED) applications.As a novel temperature sensing material,the maximum relative sensitivity of Ca_(3)Sc_(2)Ge_(3)O_(12):Tb^(3+),Eu^(3+)phosphor is 0.1044 K-1(298 K),highlighting its potential for applications in temperature sensing.展开更多
Upconversion luminescent(UCL)materials have broad application prospects in the field of temperature sensing;thus,improving the luminescence performance and temperature measurement sensitivity of upconversion phosphors...Upconversion luminescent(UCL)materials have broad application prospects in the field of temperature sensing;thus,improving the luminescence performance and temperature measurement sensitivity of upconversion phosphors is highly important.In this study,SrAl_(2)Si_(2)O_(8)with good thermal stability was doped with Ho^(3+)and Yb^(3+),and the optimal concentration was determined to be S rAl_(2)Si_(2)O_(8):1%Ho^(3+),12%Yb^(3+)(in mole fraction).A series of(Sr_(0.87-x)Ba_(x))Al_(2)Si_(2)O_(8):1%Ho^(3+),12%Yb^(3+)phosphor samples was prepared by using a cationic substitution strategy and further doping Ba^(2+)to replace the Sr^(2+)lattice in the matrix.The re sults show that the introduction of Ba^(2+)effectively replaces Sr^(2+)and significantly increases the upconversion fluorescence emission intensity of SrAl_(2)Si_(2)O_(8):1%Ho^(3+),12%Yb^(3+)by approximately 2.9times.The temperature sensing properties of SrAl_(2)Si_(2)O_(8):1%Ho^(3+),12%Yb^(3+)and Sr_(0.3)7Ba_(0.5)0Al_(2)Si_(2)O_(8):1%Ho^(3+),12%Yb^(3+)were investigated.The Ho^(3+)-based5F5and5S2/5F4nonthermal coupled energy level fluorescence intensity ratio(FIR)techniques in the Ba_(0.3)7S r_(0.50)Al_(2)Si_(2)O_(8):1%Ho^(3+),12%Yb^(3+)phosphors show a maximum temperature measurement absolute sensitivity of 4.32%/K at 573 K and a maximum relative sensitivity of 1.08%/K at 373 K;these values are 5.8 and 3.2 times greater,respectively,than that of the non-Ba^(2+)-doped SrAl_(2)Si_(2)O_(8):1%Ho^(3+),12%Yb^(3+)phosphor.These results not only confirm the effectiveness of the cation substitution strategy in enhancing the upconversion luminescence performance and temperature sensing characteristics but also provide a scientific basis for the design of high-performance optical temperature sensors.展开更多
Acetone,as widely used reagents in industry and laboratories,are extremely harmful to the human.So the detection of acetone gas concentrations and leaks in special environments at room temperature is essential.Herein,...Acetone,as widely used reagents in industry and laboratories,are extremely harmful to the human.So the detection of acetone gas concentrations and leaks in special environments at room temperature is essential.Herein,the nanocomposite combining SnO-SnO_(2)(p-n junction)and Ti_(3)C_(2)T_(x) MXene was successfully synthesized by a one-step hydrothermal method.Because of the existence of a small amount of oxygen during the hydrothermal conditions,part of the p-type SnO was oxidized to n-type SnO_(2),forming in-situ p-n junctions on the surface of Sn O.The hamburger-like SnO-SnO_(2)/Ti_(3)C_(2)T_(x) sensor exhibited improved acetone gas sensing response of 12.1(R_(g)/R_(a))at room temperature,which were nearly 11 and 4 times higher than those of pristine Ti_(3)C_(2)T_(x) and pristine SnO-SnO_(2),respectively.Moreover,it expressed a short recovery time(9 s)and outstanding reproducibility.Because of the different work functions,the Schottky barrier was formed between the SnO and the Ti_(3)C_(2)T_(x) nanosheets,acting as a hole accumulation layer(HALs)between Ti_(3)C_(2)T_(x) and tin oxides.Herein,the sensing mechanism based on the formation of hetero-junctions and high conductivity of the metallic phase of Ti_(3)C_(2)T_(x) MXene in SnO-SnO_(2)/Ti_(3)C_(2)T_(x) sensors was discussed in detail.展开更多
High-performance gas sensing materials operated at room temperature(RT) are attractive for a variety of real-time gas monitoring applications,especially with the excellent durability and flexibility of wearable sensor...High-performance gas sensing materials operated at room temperature(RT) are attractive for a variety of real-time gas monitoring applications,especially with the excellent durability and flexibility of wearable sensor.The constructing heterostructure is one of the significant approaches in design strategies of sensing materials.This heterostructure effectively increases the active site for improving sensing performance and decreasing energy consumption.Herein,the heterostructure of Au nanoparticles modified CeO_(2)@carbon-quantum-dots(Au/CeO_(2)@CQDs) with a three-dimensional(3D) scaffold structure are successfully synthesized by an effective strategy,which can apply for preparing flexible gas sensor.The gas sensing properties of Au/CeO_(2)@CQDs based on flexible substrate are obtained under long-term repeated NO_(2) exposure at RT.Meanwhile,the long-term mechanical stability of this gas sensing device is also detected after different bending cycles.The Au/CeO_(2)@CQDs based on flexible substrate sensor exhibits excellent performance,including higher sensitivity(47.2),faster response(18 s)and recovery time(22 s) as well as longer-term stability than performance of pure materials.The obtained sensor also reveals outstanding mechanical flexibility,which is only a tiny response fluctuation(8.1%) after 500 bending/relaxing cycles.Therefore,our study demonstrates the enormous potential of this sensing materials for hazardous gas monitoring in future portable and wearable sensing platform.展开更多
The research work has been seldom done about cloverleaf junction expression in a 3-dimensional city model (3DCM). The main reason is that the cloverleaf junction is often in a complex and enormous construction. Its ma...The research work has been seldom done about cloverleaf junction expression in a 3-dimensional city model (3DCM). The main reason is that the cloverleaf junction is often in a complex and enormous construction. Its main body is bestraddle in air,and has aerial intersections between its parts. This complex feature made cloverleaf junction quite different from buildings and terrain, therefore, it is difficult to express this kind of spatial objects in the same way as for buildings and terrain. In this paper,authors analyze spatial characteristics of cloverleaf junction, propose an all-constraint points TIN algorithm to partition cloverleaf junction road surface, and develop a method to visualize cloverleaf junction road surface using TIN. In order to manage cloverleaf junction data efficiently, the authors also analyzed the mechanism of 3DCM data management, extended BLOB type in relational database, and combined R-tree index to manage 3D spatial data. Based on this extension, an appropriate data展开更多
Using elementary integral method, a complete classification of all possible exact traveling wave solutions to （3＋1）-dimensional Nizhnok-Novikov-Veselov equation is given. Some solutions are new.
Using the modified find some new exact solutions to Lie point symmetry groups and also get conservation laws, of the CK＇s direct method, we build the relationship between new solutions and old ones and the （3＋1）-d...Using the modified find some new exact solutions to Lie point symmetry groups and also get conservation laws, of the CK＇s direct method, we build the relationship between new solutions and old ones and the （3＋1）-dimensional potentiaial-YTSF equation. Baaed on the invariant group theory, Lie symmetries of the （3＋1）-dimensional potential-YTSF equation are obtained. We equation with the given Lie symmetry.展开更多
Mesoporous semiconducting metal oxides(SMOs)heterojunctions are appealing sensors for gas detecting.However,due to the different hydrolysis and condensation mechanism of every metal precursor and the contradiction bet...Mesoporous semiconducting metal oxides(SMOs)heterojunctions are appealing sensors for gas detecting.However,due to the different hydrolysis and condensation mechanism of every metal precursor and the contradiction between high crystallinity and high surface area,the synthesis of mesoporous SMOs heterojunctions with highly o rdered mesostructures,highly crystallized frameworks,and high surface area remains a huge challenge.In this work,we develop a novel"acid-base pair"adjusted solvent evaporation induced self-assembly(EISA)strategy to prepare highly crystallized ordered mesoporous TiO2/WO3(OM-TiO2/WO3)heterojunctions.The WCl6 and titanium isopropoxide(TIPO)are used as the precursors,respectively,which function as the"acid-base pair",enabling the coassembly with the structure directing agent(PEO-b-PS)into highly ordered meso structures.In addition,PEO-b-PS can be converted to rigid carbon which can protect the meso structures from collapse during the crystallization process.The resultant OM-TiO2/WO3 heterojunctions possess primitive cubic mesostructures,large pore size(~21.1 nm),highly crystalline frameworks and surface area(~98 m2/g).As a sensor for acetone,the obtained OM-TiO2/WO3 show excellent re sponse/recovery perfo rmance(3 s/5 s),good linear dependence,repeatability,selectivity,and long-term stability(35 days).展开更多
The humidity sensing properties of La^3＋ and K^＋ co-doped Ti0.9Sn0.1O2 thin films were investigated. The humidity sensitive thin films were prepared by sol-gel method on alumina substrates. The sensing behaviors of ...The humidity sensing properties of La^3＋ and K^＋ co-doped Ti0.9Sn0.1O2 thin films were investigated. The humidity sensitive thin films were prepared by sol-gel method on alumina substrates. The sensing behaviors of thin films were inspected at different sintering temperatures by constructing a humidity-impedance measuring system. It was found that the addition of rare earth ion La^3＋ and alkali ion K^＋ was beneficial for improving the humidity sensitive properties of the samples and La0.003K0.5Ti0.9Sn0.1O2 sintered at 500 ℃ for 4 h showed the best humidity sensing properties. The impedance of this thin film decreased from 109 to 104 Ω with excellent linearity in the humidity range of 11%-95%. Narrow hysteresis loop, prominent stability and high sensitivity were obtained. The effects of dopant con-tent and doping mechanism on humidity sensitivity were also discussed in terms of segregation of rare earth ions at grain boundaries and granularity of crystalline and influence of K^＋ on the decrease in the intrinsic resistance of the materials, and increase in the number of wa-ter adsorption sites.展开更多
This study examined the dynamic characteristics of upper airway collapse at soft palate level in patients with obstructive sleep apnea/hypopnea syndrome（OSAHS） by using dynamic 3-Dimensional（3-D） CT imaging.A tota...This study examined the dynamic characteristics of upper airway collapse at soft palate level in patients with obstructive sleep apnea/hypopnea syndrome（OSAHS） by using dynamic 3-Dimensional（3-D） CT imaging.A total of 41 male patients who presented with 2 of the following symptoms,i.e.,daytime sleepiness and fatigue,frequent snoring,and apnea with witness,were diagnosed as having OSAHS.They underwent full-night polysomnography and then dynamic 3-D CT imaging of the upper airway during quiet breathing and in Muller＇s maneuver.The soft palate length（SPL）,the minimal cross-sectional area of the retropalatal region（mXSA-RP）,and the vertical distance from the hard palate to the upper posterior part of the hyoid（hhL） were compared between the two breathing states.These parameters,together with hard palate length（HPL）,were also compared between mild/moderate and severe OSAHS groups.Association of these parameters with the severity of OSAHS [as reflected by apnea hypopnea index（AHI） and the lowest saturation of blood oxygen（LSaO2）] was examined.The results showed that 31 patients had severe OSAHS,and 10 mild/moderate OSAHS.All the patients had airway obstruction at soft palate level.mXSA-RP was significantly decreased and SPL remarkably increased during Muller＇s maneuver as compared with the quiet breathing state.There were no significant differences in these airway parameters（except the position of the hyoid bone） between severe and mild/moderate OSAHS groups.And no significant correlation between these airway parameters and the severity of OSAHS was found.The position of hyoid was lower in the severe OSAHS group than in the mild/moderate OSAHS group.The patients in group with body mass index（BMI）≥26 had higher collapse ratio of mXSA-RP,greater neck circumference and smaller mXSA-RP in the Muller＇s maneuver than those in group with BMI26（P0.05 for all）.It was concluded that dynamic 3-D CT imaging could dynamically show the upper airway changes at soft palate level in OSAHS patients.All the OSAHS patients had airway obstruction of various degrees at soft palate level.But no correlation was observed between the airway change at soft palate level and the severity of OSAHS.The patients in group with BMI≥26 were more likely to develop airway obstruction at soft palate level than those with BMI26.展开更多
Photon upconversion of lanthanides has been a powerful means to convert low-energy photons into high-energy ones.However,in contrast to the mostly investigated lanthanide ions,it has remained a challenge for the effic...Photon upconversion of lanthanides has been a powerful means to convert low-energy photons into high-energy ones.However,in contrast to the mostly investigated lanthanide ions,it has remained a challenge for the efficient upconversion of Nd^(3+)due to the deleterious concentration quenching effect.Here we report an efficient strategy to enhance the upconversion of Nd^(3+)through the Yb^(3+)-mediated energy cycling in a core-shell-shell nanostructure.Both Nd^(3+)and Yb^(3+)are confined in the interlayer,and the presence of Yb^(3+)in the Nd-sublattice provides a more matched energy for the upconversion transitions occurring at the intermediate state of Nd^(3+)towards much better population at its emissive levels.Moreover,this design also minimizes the possible cross-relaxation processes at both intermediate level and the emissive levels of Nd^(3+)which are the primary factors limiting the upconversion performance for the Nd^(3+)-doped materials.Such energy cycling-enhanced upconversion shows promise in temperature sensing.展开更多
Cubic phase Tm^(3+)/Yb^(3+):Y_(2)O_(3) and Tm^(3+)/Yb^(3+)/Gd^(3+):Y_(2)O_(3) phosphors were prepared by low temperature combustion technique for upconversion emission in UV-visible range.The 980 nm excitation has gen...Cubic phase Tm^(3+)/Yb^(3+):Y_(2)O_(3) and Tm^(3+)/Yb^(3+)/Gd^(3+):Y_(2)O_(3) phosphors were prepared by low temperature combustion technique for upconversion emission in UV-visible range.The 980 nm excitation has generated UV emission at 314 nm in tridoped phosphor due to the energy transfer from Tm^(3+) to Gd^(3+)ion.Characteristic emission bands from Tm^(3+) are also observed in both the phosphors.Thermally coupled Stark sublevels ^(1)G_(4(a))(476 nm) and ^(1)G_(4(b))(488 nm) of Tm^(3+) ion were utilised for optical thermometry using fluorescent intensity ratio(FIR) method.The result shows that maximum absolute sensitivity in tridoped phosphor is observed to be 1.33 × 10^(-3) K^(-1) at 298 K.Moreover,temperature rise of phosphor at various pump power densities was also measured and it is estimated to achieve 407 K at the pump power density of 38.46 W/cm^(2).展开更多
Based on the Pfaffian derivative formulae,a Grammian determinant solution for a(3+1)-dimensionalsoliton equation is obtained.Moreover,the Pfaffianization procedure is applied for the equation to generate a newcoupled ...Based on the Pfaffian derivative formulae,a Grammian determinant solution for a(3+1)-dimensionalsoliton equation is obtained.Moreover,the Pfaffianization procedure is applied for the equation to generate a newcoupled system.At last,a Gram-type Pfaffian solution to the new coupled system is given.展开更多
Optical temperature sensing based on the fluorescence intensity ratio(FIR)of red emission for lanthanide ions holds significant relevance in non-contact temperature measurement for biological application.In this study...Optical temperature sensing based on the fluorescence intensity ratio(FIR)of red emission for lanthanide ions holds significant relevance in non-contact temperature measurement for biological application.In this study,the perovskite-structured KZnF_(3)is utilized as a host material for Er^(3+)to achieve a high-purity upconversion(UC)red emission.The observed Stark splitting of the red emission peak provides evidence of the energy level splitting of Er^(3+).Group theory is employed to decompose the spectral branching of Er^(3+)under the point group symmetry of KZnF_(3),allowing for the derivation of Stark splitting energy levels induced by the crystal field effect.The optical temperature-sensing behavior of the red UC luminescence was investigated,specifically examining the FIR of the splitting sub-peaks,which exhibited an exponential relationship with temperature.The KZnF_(3):Yb^(3+),Er^(3+)demonstrated a relative sensitivity(S_(r))of 0.00182%·K^(-1)at 298 K,highlighting its excellent response to temperature.Ex vivo bio-thermometry experiments conducted on chicken breast validated the material's ability to penetrate biological tissues and showed its significant sensitivity of the FIR to temperature.These results establish KZnF_(3):Yb^(3+),Er^(3+)as a promising material for optical thermometry in various biological applications.展开更多
The exploration of building detection plays an important role in urban planning,smart city and military.Aiming at the problem of high overlapping ratio of detection frames for dense building detection in high resoluti...The exploration of building detection plays an important role in urban planning,smart city and military.Aiming at the problem of high overlapping ratio of detection frames for dense building detection in high resolution remote sensing images,we present an effective YOLOv3 framework,corner regression-based YOLOv3(Correg-YOLOv3),to localize dense building accurately.This improved YOLOv3 algorithm establishes a vertex regression mechanism and an additional loss item about building vertex offsets relative to the center point of bounding box.By extending output dimensions,the trained model is able to output the rectangular bounding boxes and the building vertices meanwhile.Finally,we evaluate the performance of the Correg-YOLOv3 on our self-produced data set and provide a comparative analysis qualitatively and quantitatively.The experimental results achieve high performance in precision(96.45%),recall rate(95.75%),F1 score(96.10%)and average precision(98.05%),which were 2.73%,5.4%,4.1%and 4.73%higher than that of YOLOv3.Therefore,our proposed algorithm effectively tackles the problem of dense building detection in high resolution images.展开更多
基金supported by the National Research Foundation of Korea(NRF)Grant funded by the Korea government(MSIT)(No.2019R1A2C1008746).
文摘Nowadays,there is a growing global demand for high-performance room temperature gas sensing de-vices.In this context,we aim to explore the advancements in two-dimensional(2D)Ti_(3)C_(2)MXene role for toxic NO_(2)gas sensing at room temperature.The distinctive advantages of 2D Ti_(3)C_(2)MXene,including high electrical conductivity,ample surface area,surface termination groups,and layer structure have garnered significant attention towards NO_(2)gas adsorption.Further,the compatible regularity of Ti_(3)C_(2)MXene at the interface of various semiconductors directed the development of potential room-temperature NO_(2)gas sensing devices.Further,the leveraging gas sensing(selectivity,response,and recovery)characteristics be-come increasing attention on Ti_(3)C_(2)MXene/semiconductor interfaces than pure Ti_(3)C_(2)MXene.Elaborative control on the depletion layer through the Schottky barrier formation distinguished the room tempera-ture NO_(2)gas sensing and led to the evolution of electrophilic NO_(2)gas molecule interaction.Remarkably,the great processability of Ti_(3)C_(2)MXene/semiconductor interface is sensitive to the low detection limit(LOD)of NO_(2)gas at parts per billion(ppb)conditions.On the other hand,this review demonstrates the room temperature optoelectronic NO_(2)gas sensing capabilities of Ti_(3)C_(2)-based composites for emphasiz-ing selectivity and recovery.Interestingly,the Ti_(3)C_(2)MXene/semiconductor composite builds immunity against the atmosphere humidity and achieves stable NO_(2)gas sensing.Finally,we have provided conclu-sions and key points to advance the research on room temperature NO_(2)gas sensing of Ti_(3)C_(2)integrated semiconductors.
基金financially supported by the Scientific Research Foundation of North China University of Technology(Grant Nos.11005136024XN147-87 and 110051360024XN151-86).
文摘With respect to oceanic fluid dynamics,certain models have appeared,e.g.,an extended time-dependent(3+1)-dimensional shallow water wave equation in an ocean or a river,which we investigate in this paper.Using symbolic computation,we find out,on one hand,a set of bilinear auto-Backlund transformations,which could connect certain solutions of that equation with other solutions of that equation itself,and on the other hand,a set of similarity reductions,which could go from that equation to a known ordinary differential equation.The results in this paper depend on all the oceanic variable coefficients in that equation.
基金supported by the BK21 FOUR funded by the Ministry of Education of Korea and National Research Foundation of Korea,a Korea Agency for Infrastructure Technology Advancement(KAIA)grant funded by the Ministry of Land,Infrastructure,and Transport(Grant 1615013176)IITP(Institute of Information&Coummunications Technology Planning&Evaluation)-ICAN(ICT Challenge and Advanced Network of HRD)grant funded by the Korea government(Ministry of Science and ICT)(RS-2024-00438411).
文摘This paper proposes a novel cargo loading algorithm applicable to automated conveyor-type loading systems.The algorithm offers improvements in computational efficiency and robustness by utilizing the concept of discrete derivatives and introducing logistics-related constraints.Optional consideration of the rotation of the cargoes was made to further enhance the optimality of the solutions,if possible to be physically implemented.Evaluation metrics were developed for accurate evaluation and enhancement of the algorithm’s ability to efficiently utilize the loading space and provide a high level of dynamic stability.Experimental results demonstrate the extensive robustness of the proposed algorithm to the diversity of cargoes present in Business-to-Consumer environments.This study contributes practical advancements in both cargo loading optimization and automation of the logistics industry,with potential applications in last-mile delivery services,warehousing,and supply chain management.
文摘Lie symmetry analysis is applied to a(3+1)-dimensional combined potential Kadomtsev-Petviashvili equation with B-type Kadomtsev-Petviashvili equation(pKP-BKP equation)and the corresponding similarity reduction equations are obtained with the different infinitesimal generators.Invariant solutions with arbitrary functions and constants for the(3+1)-dimensional pKP-BKP equation,including the lump solution,the periodic-lump solution,the two-kink solution,the breather solution and the lump-two-kink solution,have been studied analytically and graphically.
基金the Natural Science Foundation of Inner Mongolia Autonomous Region(Grant No.2024MS01003)the First-Class Disciplines Project,Inner Mongolia Autonomous Region,China(Grant Nos.YLXKZX-NSD-001 and YLXKZX-NSD-009)the Program for Innovative Research Team in Universities of Inner Mongolia Autonomous Region(Grant No.NMGIRT2414).
文摘In this article,a Generalized Calogero-Bogoyavlenskii-Schiff(CBS)equation is studied,serving as an extended shallow water wave model in higher dimensions.Firstly,utilizing the Bell polynomial method,the bilinear form of the equation,bilinear Bäcklund transformation,Lax pair and infinite conservation laws are derived,confirming the equation’s complete integrability in the context of the Lax pair.Subsequently,the nonlinear superposition formula of the equation is constructed based on the derived bilinear Bäcklund transformation and an array of infinite superposition soliton solutions of the equation are formulated using this nonlinear superposition formula.Lastly,leveraging the obtained bilinear equation,infinite superposition solutions of various functional types are constructed.Their dynamic characteristics are analyzed through illustrated solution images.It is noteworthy that this paper not only uncovers a multitude of properties through the Bell polynomial method but also derives both infinite linear and nonlinear superposition solutions,enriching the diversity of solutions,these aspects have not been previously explored in existing literature.
基金Project supported by the National Natural Science Foundation of China (52274273)。
文摘A set of germanate garnet phosphors containing Tb^(3+)and Eu^(3+)were adequately synthesized using the high-temperature solid-state technique.The structural properties,photoluminescence characteristics,fluorescence lifetimes,and temperature-sensing capabilities of the phosphors were thoroughly investigated.X-ray diffraction confirms the crystalline structure of the phosphors,while photoluminescence spectra reveal a colour shift attributed to the trans fer of energy from Tb^(3+)to Eu^(3+)as the concentration of Eu^(3+)increases.The phosphors excited by UV light display a transition in colour from green to yellow,and subsequently to red,which can be used as a colour tunable phosphor in white light-emitting diode(w-LED) applications.As a novel temperature sensing material,the maximum relative sensitivity of Ca_(3)Sc_(2)Ge_(3)O_(12):Tb^(3+),Eu^(3+)phosphor is 0.1044 K-1(298 K),highlighting its potential for applications in temperature sensing.
基金Project supported by the National Natural Science Foundation of China(12264050)Natural Science Foundation of Xinjiang Uygur Autonomous Region(2022D01C727)Talent Project of Tianchi Doctoral Program in Xinjiang Uygur Autonomous Region(0301050903)。
文摘Upconversion luminescent(UCL)materials have broad application prospects in the field of temperature sensing;thus,improving the luminescence performance and temperature measurement sensitivity of upconversion phosphors is highly important.In this study,SrAl_(2)Si_(2)O_(8)with good thermal stability was doped with Ho^(3+)and Yb^(3+),and the optimal concentration was determined to be S rAl_(2)Si_(2)O_(8):1%Ho^(3+),12%Yb^(3+)(in mole fraction).A series of(Sr_(0.87-x)Ba_(x))Al_(2)Si_(2)O_(8):1%Ho^(3+),12%Yb^(3+)phosphor samples was prepared by using a cationic substitution strategy and further doping Ba^(2+)to replace the Sr^(2+)lattice in the matrix.The re sults show that the introduction of Ba^(2+)effectively replaces Sr^(2+)and significantly increases the upconversion fluorescence emission intensity of SrAl_(2)Si_(2)O_(8):1%Ho^(3+),12%Yb^(3+)by approximately 2.9times.The temperature sensing properties of SrAl_(2)Si_(2)O_(8):1%Ho^(3+),12%Yb^(3+)and Sr_(0.3)7Ba_(0.5)0Al_(2)Si_(2)O_(8):1%Ho^(3+),12%Yb^(3+)were investigated.The Ho^(3+)-based5F5and5S2/5F4nonthermal coupled energy level fluorescence intensity ratio(FIR)techniques in the Ba_(0.3)7S r_(0.50)Al_(2)Si_(2)O_(8):1%Ho^(3+),12%Yb^(3+)phosphors show a maximum temperature measurement absolute sensitivity of 4.32%/K at 573 K and a maximum relative sensitivity of 1.08%/K at 373 K;these values are 5.8 and 3.2 times greater,respectively,than that of the non-Ba^(2+)-doped SrAl_(2)Si_(2)O_(8):1%Ho^(3+),12%Yb^(3+)phosphor.These results not only confirm the effectiveness of the cation substitution strategy in enhancing the upconversion luminescence performance and temperature sensing characteristics but also provide a scientific basis for the design of high-performance optical temperature sensors.
基金supported financially by the National Natural Science Foundation of China(Nos.,51572158 and 51972200)the Graduate Innovation Fund of Shaanxi University of Science&Technology+2 种基金funded by the Japan Society for the Promotion of Science(JSPS)Grant-in-Aid for the Scientific Research(KAKENHI Nos.20H00297 and Innovative Area“Mixed Anion”(No.16H06439))the Nippon Sheet Glass Foundation for Materials Science and Engineeringby the Dynamic Alliance for Open Innovations Bridging Human,Environment and Materials,the Cooperative Research Program of“Network Joint Research Center for Materials and Devices”。
文摘Acetone,as widely used reagents in industry and laboratories,are extremely harmful to the human.So the detection of acetone gas concentrations and leaks in special environments at room temperature is essential.Herein,the nanocomposite combining SnO-SnO_(2)(p-n junction)and Ti_(3)C_(2)T_(x) MXene was successfully synthesized by a one-step hydrothermal method.Because of the existence of a small amount of oxygen during the hydrothermal conditions,part of the p-type SnO was oxidized to n-type SnO_(2),forming in-situ p-n junctions on the surface of Sn O.The hamburger-like SnO-SnO_(2)/Ti_(3)C_(2)T_(x) sensor exhibited improved acetone gas sensing response of 12.1(R_(g)/R_(a))at room temperature,which were nearly 11 and 4 times higher than those of pristine Ti_(3)C_(2)T_(x) and pristine SnO-SnO_(2),respectively.Moreover,it expressed a short recovery time(9 s)and outstanding reproducibility.Because of the different work functions,the Schottky barrier was formed between the SnO and the Ti_(3)C_(2)T_(x) nanosheets,acting as a hole accumulation layer(HALs)between Ti_(3)C_(2)T_(x) and tin oxides.Herein,the sensing mechanism based on the formation of hetero-junctions and high conductivity of the metallic phase of Ti_(3)C_(2)T_(x) MXene in SnO-SnO_(2)/Ti_(3)C_(2)T_(x) sensors was discussed in detail.
基金financially supported by the Natural Science Foundation of Shandong Province (Nos. ZR2021QB136 and ZR2022MH091)the Innovation and Entrepreneurship Training Program for Undergraduates of Shandong Province (No.S202110439100)+2 种基金Tai'an Science and Technology Innovation Development Project (No.2021GX068)the Academic Promotion Program of Shandong First Medical University (No. 2019QL008)the Chinese Academy of Sciences。
文摘High-performance gas sensing materials operated at room temperature(RT) are attractive for a variety of real-time gas monitoring applications,especially with the excellent durability and flexibility of wearable sensor.The constructing heterostructure is one of the significant approaches in design strategies of sensing materials.This heterostructure effectively increases the active site for improving sensing performance and decreasing energy consumption.Herein,the heterostructure of Au nanoparticles modified CeO_(2)@carbon-quantum-dots(Au/CeO_(2)@CQDs) with a three-dimensional(3D) scaffold structure are successfully synthesized by an effective strategy,which can apply for preparing flexible gas sensor.The gas sensing properties of Au/CeO_(2)@CQDs based on flexible substrate are obtained under long-term repeated NO_(2) exposure at RT.Meanwhile,the long-term mechanical stability of this gas sensing device is also detected after different bending cycles.The Au/CeO_(2)@CQDs based on flexible substrate sensor exhibits excellent performance,including higher sensitivity(47.2),faster response(18 s)and recovery time(22 s) as well as longer-term stability than performance of pure materials.The obtained sensor also reveals outstanding mechanical flexibility,which is only a tiny response fluctuation(8.1%) after 500 bending/relaxing cycles.Therefore,our study demonstrates the enormous potential of this sensing materials for hazardous gas monitoring in future portable and wearable sensing platform.
文摘The research work has been seldom done about cloverleaf junction expression in a 3-dimensional city model (3DCM). The main reason is that the cloverleaf junction is often in a complex and enormous construction. Its main body is bestraddle in air,and has aerial intersections between its parts. This complex feature made cloverleaf junction quite different from buildings and terrain, therefore, it is difficult to express this kind of spatial objects in the same way as for buildings and terrain. In this paper,authors analyze spatial characteristics of cloverleaf junction, propose an all-constraint points TIN algorithm to partition cloverleaf junction road surface, and develop a method to visualize cloverleaf junction road surface using TIN. In order to manage cloverleaf junction data efficiently, the authors also analyzed the mechanism of 3DCM data management, extended BLOB type in relational database, and combined R-tree index to manage 3D spatial data. Based on this extension, an appropriate data
基金The project supported by Scientific Research Fund of Heilongjiang Province of China under Grant No. 11511008The author would like to thank referees for their valuable suggestions.
文摘Using elementary integral method, a complete classification of all possible exact traveling wave solutions to （3＋1）-dimensional Nizhnok-Novikov-Veselov equation is given. Some solutions are new.
基金The project supported by the Natural Science Foundation of Shandong Province of China under Grant No. 2004zx16 tCorresponding author, E-maih zzlh100@163.com
文摘Using the modified find some new exact solutions to Lie point symmetry groups and also get conservation laws, of the CK＇s direct method, we build the relationship between new solutions and old ones and the （3＋1）-dimensional potentiaial-YTSF equation. Baaed on the invariant group theory, Lie symmetries of the （3＋1）-dimensional potential-YTSF equation are obtained. We equation with the given Lie symmetry.
基金supported by the National Natural Science Foundation of China(Nos.51822202 and 51772050)China Postdoctoral Science Foundation(No.2019M651342)+2 种基金Shanghai Rising-Star Program(No.18QA1400100)Youth Top-notch Talent Support Program of Shanghai,the Shanghai Committee of Science and Technology,China(No.19520713200)DHU Distinguished Young Professor Program and Fundamental Research Funds for the Central Universities。
文摘Mesoporous semiconducting metal oxides(SMOs)heterojunctions are appealing sensors for gas detecting.However,due to the different hydrolysis and condensation mechanism of every metal precursor and the contradiction between high crystallinity and high surface area,the synthesis of mesoporous SMOs heterojunctions with highly o rdered mesostructures,highly crystallized frameworks,and high surface area remains a huge challenge.In this work,we develop a novel"acid-base pair"adjusted solvent evaporation induced self-assembly(EISA)strategy to prepare highly crystallized ordered mesoporous TiO2/WO3(OM-TiO2/WO3)heterojunctions.The WCl6 and titanium isopropoxide(TIPO)are used as the precursors,respectively,which function as the"acid-base pair",enabling the coassembly with the structure directing agent(PEO-b-PS)into highly ordered meso structures.In addition,PEO-b-PS can be converted to rigid carbon which can protect the meso structures from collapse during the crystallization process.The resultant OM-TiO2/WO3 heterojunctions possess primitive cubic mesostructures,large pore size(~21.1 nm),highly crystalline frameworks and surface area(~98 m2/g).As a sensor for acetone,the obtained OM-TiO2/WO3 show excellent re sponse/recovery perfo rmance(3 s/5 s),good linear dependence,repeatability,selectivity,and long-term stability(35 days).
文摘The humidity sensing properties of La^3＋ and K^＋ co-doped Ti0.9Sn0.1O2 thin films were investigated. The humidity sensitive thin films were prepared by sol-gel method on alumina substrates. The sensing behaviors of thin films were inspected at different sintering temperatures by constructing a humidity-impedance measuring system. It was found that the addition of rare earth ion La^3＋ and alkali ion K^＋ was beneficial for improving the humidity sensitive properties of the samples and La0.003K0.5Ti0.9Sn0.1O2 sintered at 500 ℃ for 4 h showed the best humidity sensing properties. The impedance of this thin film decreased from 109 to 104 Ω with excellent linearity in the humidity range of 11%-95%. Narrow hysteresis loop, prominent stability and high sensitivity were obtained. The effects of dopant con-tent and doping mechanism on humidity sensitivity were also discussed in terms of segregation of rare earth ions at grain boundaries and granularity of crystalline and influence of K^＋ on the decrease in the intrinsic resistance of the materials, and increase in the number of wa-ter adsorption sites.
文摘This study examined the dynamic characteristics of upper airway collapse at soft palate level in patients with obstructive sleep apnea/hypopnea syndrome（OSAHS） by using dynamic 3-Dimensional（3-D） CT imaging.A total of 41 male patients who presented with 2 of the following symptoms,i.e.,daytime sleepiness and fatigue,frequent snoring,and apnea with witness,were diagnosed as having OSAHS.They underwent full-night polysomnography and then dynamic 3-D CT imaging of the upper airway during quiet breathing and in Muller＇s maneuver.The soft palate length（SPL）,the minimal cross-sectional area of the retropalatal region（mXSA-RP）,and the vertical distance from the hard palate to the upper posterior part of the hyoid（hhL） were compared between the two breathing states.These parameters,together with hard palate length（HPL）,were also compared between mild/moderate and severe OSAHS groups.Association of these parameters with the severity of OSAHS [as reflected by apnea hypopnea index（AHI） and the lowest saturation of blood oxygen（LSaO2）] was examined.The results showed that 31 patients had severe OSAHS,and 10 mild/moderate OSAHS.All the patients had airway obstruction at soft palate level.mXSA-RP was significantly decreased and SPL remarkably increased during Muller＇s maneuver as compared with the quiet breathing state.There were no significant differences in these airway parameters（except the position of the hyoid bone） between severe and mild/moderate OSAHS groups.And no significant correlation between these airway parameters and the severity of OSAHS was found.The position of hyoid was lower in the severe OSAHS group than in the mild/moderate OSAHS group.The patients in group with body mass index（BMI）≥26 had higher collapse ratio of mXSA-RP,greater neck circumference and smaller mXSA-RP in the Muller＇s maneuver than those in group with BMI26（P0.05 for all）.It was concluded that dynamic 3-D CT imaging could dynamically show the upper airway changes at soft palate level in OSAHS patients.All the OSAHS patients had airway obstruction of various degrees at soft palate level.But no correlation was observed between the airway change at soft palate level and the severity of OSAHS.The patients in group with BMI≥26 were more likely to develop airway obstruction at soft palate level than those with BMI26.
基金Project supported by the National Natural Science Foundation of China(51972119)the Fundamental Research Funds for the Central Universities(2020ZYGXZR100)+2 种基金the State Key Laboratory of Luminescent Materials and Devices(Skllmd-2021-01)the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(2017BT01X137)the Research Grants Council of Hong Kong for a General Research Fund(11205219)。
文摘Photon upconversion of lanthanides has been a powerful means to convert low-energy photons into high-energy ones.However,in contrast to the mostly investigated lanthanide ions,it has remained a challenge for the efficient upconversion of Nd^(3+)due to the deleterious concentration quenching effect.Here we report an efficient strategy to enhance the upconversion of Nd^(3+)through the Yb^(3+)-mediated energy cycling in a core-shell-shell nanostructure.Both Nd^(3+)and Yb^(3+)are confined in the interlayer,and the presence of Yb^(3+)in the Nd-sublattice provides a more matched energy for the upconversion transitions occurring at the intermediate state of Nd^(3+)towards much better population at its emissive levels.Moreover,this design also minimizes the possible cross-relaxation processes at both intermediate level and the emissive levels of Nd^(3+)which are the primary factors limiting the upconversion performance for the Nd^(3+)-doped materials.Such energy cycling-enhanced upconversion shows promise in temperature sensing.
基金supported by the DST-SERB,New Delhi,India (EMR/000228/2017)TEQIP-Ⅲ,Ministry of Education,Government of India。
文摘Cubic phase Tm^(3+)/Yb^(3+):Y_(2)O_(3) and Tm^(3+)/Yb^(3+)/Gd^(3+):Y_(2)O_(3) phosphors were prepared by low temperature combustion technique for upconversion emission in UV-visible range.The 980 nm excitation has generated UV emission at 314 nm in tridoped phosphor due to the energy transfer from Tm^(3+) to Gd^(3+)ion.Characteristic emission bands from Tm^(3+) are also observed in both the phosphors.Thermally coupled Stark sublevels ^(1)G_(4(a))(476 nm) and ^(1)G_(4(b))(488 nm) of Tm^(3+) ion were utilised for optical thermometry using fluorescent intensity ratio(FIR) method.The result shows that maximum absolute sensitivity in tridoped phosphor is observed to be 1.33 × 10^(-3) K^(-1) at 298 K.Moreover,temperature rise of phosphor at various pump power densities was also measured and it is estimated to achieve 407 K at the pump power density of 38.46 W/cm^(2).
文摘Based on the Pfaffian derivative formulae,a Grammian determinant solution for a(3+1)-dimensionalsoliton equation is obtained.Moreover,the Pfaffianization procedure is applied for the equation to generate a newcoupled system.At last,a Gram-type Pfaffian solution to the new coupled system is given.
基金financially supported by Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)"Qinglan Project"Young and Middle-aged Academic Leaders Program of Jiangsu Province。
文摘Optical temperature sensing based on the fluorescence intensity ratio(FIR)of red emission for lanthanide ions holds significant relevance in non-contact temperature measurement for biological application.In this study,the perovskite-structured KZnF_(3)is utilized as a host material for Er^(3+)to achieve a high-purity upconversion(UC)red emission.The observed Stark splitting of the red emission peak provides evidence of the energy level splitting of Er^(3+).Group theory is employed to decompose the spectral branching of Er^(3+)under the point group symmetry of KZnF_(3),allowing for the derivation of Stark splitting energy levels induced by the crystal field effect.The optical temperature-sensing behavior of the red UC luminescence was investigated,specifically examining the FIR of the splitting sub-peaks,which exhibited an exponential relationship with temperature.The KZnF_(3):Yb^(3+),Er^(3+)demonstrated a relative sensitivity(S_(r))of 0.00182%·K^(-1)at 298 K,highlighting its excellent response to temperature.Ex vivo bio-thermometry experiments conducted on chicken breast validated the material's ability to penetrate biological tissues and showed its significant sensitivity of the FIR to temperature.These results establish KZnF_(3):Yb^(3+),Er^(3+)as a promising material for optical thermometry in various biological applications.
基金National Natural Science Foundation of China(No.41871305)National Key Research and Development Program of China(No.2017YFC0602204)+2 种基金Fundamental Research Funds for the Central Universities,China University of Geosciences(Wuhan)(No.CUGQY1945)Open Fund of Key Laboratory of Geological Survey and Evaluation of Ministry of Education and the Fundamental Research Funds for the Central Universities(No.GLAB2019ZR02)Open Fund of Laboratory of Urban Land Resources Monitoring and Simulation,Ministry of Natural Resources,China(No.KF-2020-05-068)。
文摘The exploration of building detection plays an important role in urban planning,smart city and military.Aiming at the problem of high overlapping ratio of detection frames for dense building detection in high resolution remote sensing images,we present an effective YOLOv3 framework,corner regression-based YOLOv3(Correg-YOLOv3),to localize dense building accurately.This improved YOLOv3 algorithm establishes a vertex regression mechanism and an additional loss item about building vertex offsets relative to the center point of bounding box.By extending output dimensions,the trained model is able to output the rectangular bounding boxes and the building vertices meanwhile.Finally,we evaluate the performance of the Correg-YOLOv3 on our self-produced data set and provide a comparative analysis qualitatively and quantitatively.The experimental results achieve high performance in precision(96.45%),recall rate(95.75%),F1 score(96.10%)and average precision(98.05%),which were 2.73%,5.4%,4.1%and 4.73%higher than that of YOLOv3.Therefore,our proposed algorithm effectively tackles the problem of dense building detection in high resolution images.
