Oriented graphene aerogels have limited applica-tions because the flexibility of their graphene sheets and mi-crostructure give them a low skeleton strength,insufficient compression resilience,and poor flexibility.We ...Oriented graphene aerogels have limited applica-tions because the flexibility of their graphene sheets and mi-crostructure give them a low skeleton strength,insufficient compression resilience,and poor flexibility.We report the preparation of novel aerogel materials with a much better per-formance.Using the driving force of graphene oxide(GO)self-assembly andπ-πinteractions,carbon nanotubes(CNTs)were attached to the GO sheets,and an oriented composite carbon skeleton was constructed using“hydro-plastic foam-ing”.The introduction of CNTs significantly increased the strength of the skeleton and gave the aerogel an excellent re-versible compressibility.The innovative use of cold pressing greatly improved the thermal conductivity and flexibility of the aerogel,providing new ideas for the development of high-performance aerogels.Tests show that the obtained graphene composite aerogel has a reversible compressive strain of over 90%and can withstand 500 compression cycles along the direc-tion of pore accumulation.It can endure more than 10000 bending cycles perpendicular to the direction of composite carbon layer stacking,and its in-plane thermal conductivity reaches 64.5 W·m^(-1)·K^(-1).When filled with phase change materials,the high porosity of the carbon skeleton enables the material to have a high phase change filling rate,and its phase change enthalpy is greater than 150 J/g.Thanks to the exceptional flexibility of the carbon skeleton,the macrostructure of phase change materials can be bent as needed to adapt to thermal management scenarios and conform to device shapes.This significantly enhances practical application compatibility,providing flexible support for temperature control and thermal management across diverse device forms.展开更多
Objective Primary liver cancer,predominantly hepatocellular carcinoma(HCC),is a significant global health issue,ranking as the sixth most diagnosed cancer and the third leading cause of cancer-related mortality.Accura...Objective Primary liver cancer,predominantly hepatocellular carcinoma(HCC),is a significant global health issue,ranking as the sixth most diagnosed cancer and the third leading cause of cancer-related mortality.Accurate and early diagnosis of HCC is crucial for effective treatment,as HCC and non-HCC malignancies like intrahepatic cholangiocarcinoma(ICC)exhibit different prognoses and treatment responses.Traditional diagnostic methods,including liver biopsy and contrast-enhanced ultrasound(CEUS),face limitations in applicability and objectivity.The primary objective of this study was to develop an advanced,lightweighted classification network capable of distinguishing HCC from other non-HCC malignancies by leveraging the automatic analysis of brightness changes in CEUS images.The ultimate goal was to create a user-friendly and cost-efficient computer-aided diagnostic tool that could assist radiologists in making more accurate and efficient clinical decisions.Methods This retrospective study encompassed a total of 161 patients,comprising 131 diagnosed with HCC and 30 with non-HCC malignancies.To achieve accurate tumor detection,the YOLOX network was employed to identify the region of interest(ROI)on both B-mode ultrasound and CEUS images.A custom-developed algorithm was then utilized to extract brightness change curves from the tumor and adjacent liver parenchyma regions within the CEUS images.These curves provided critical data for the subsequent analysis and classification process.To analyze the extracted brightness change curves and classify the malignancies,we developed and compared several models.These included one-dimensional convolutional neural networks(1D-ResNet,1D-ConvNeXt,and 1D-CNN),as well as traditional machine-learning methods such as support vector machine(SVM),ensemble learning(EL),k-nearest neighbor(KNN),and decision tree(DT).The diagnostic performance of each method in distinguishing HCC from non-HCC malignancies was rigorously evaluated using four key metrics:area under the receiver operating characteristic(AUC),accuracy(ACC),sensitivity(SE),and specificity(SP).Results The evaluation of the machine-learning methods revealed AUC values of 0.70 for SVM,0.56 for ensemble learning,0.63 for KNN,and 0.72 for the decision tree.These results indicated moderate to fair performance in classifying the malignancies based on the brightness change curves.In contrast,the deep learning models demonstrated significantly higher AUCs,with 1D-ResNet achieving an AUC of 0.72,1D-ConvNeXt reaching 0.82,and 1D-CNN obtaining the highest AUC of 0.84.Moreover,under the five-fold cross-validation scheme,the 1D-CNN model outperformed other models in both accuracy and specificity.Specifically,it achieved accuracy improvements of 3.8%to 10.0%and specificity enhancements of 6.6%to 43.3%over competing approaches.The superior performance of the 1D-CNN model highlighted its potential as a powerful tool for accurate classification.Conclusion The 1D-CNN model proved to be the most effective in differentiating HCC from non-HCC malignancies,surpassing both traditional machine-learning methods and other deep learning models.This study successfully developed a user-friendly and cost-efficient computer-aided diagnostic solution that would significantly enhances radiologists’diagnostic capabilities.By improving the accuracy and efficiency of clinical decision-making,this tool has the potential to positively impact patient care and outcomes.Future work may focus on further refining the model and exploring its integration with multimodal ultrasound data to maximize its accuracy and applicability.展开更多
Cotton is an essential agricultural commodity,but its global yield is greatly affected by climate change,which poses a serious threat to the agriculture sector.This review aims to provide an overview of the impact of ...Cotton is an essential agricultural commodity,but its global yield is greatly affected by climate change,which poses a serious threat to the agriculture sector.This review aims to provide an overview of the impact of climate change on cotton production and the use of genomic approaches to increase stress tolerance in cotton.This paper discusses the effects of rising temperatures,changing precipitation patterns,and extreme weather events on cotton yield.It then explores various genomic strategies,such as genomic selection and marker-assisted selection,which can be used to develop stress-tolerant cotton varieties.The review emphasizes the need for interdisciplinary research efforts and policy interventions to mitigate the adverse effects of climate change on cotton production.Furthermore,this paper presents advanced prospects,including genomic selection,gene editing,multi-omics integration,highthroughput phenotyping,genomic data sharing,climate-informed breeding,and phenomics-assisted genomic selection,for enhancing stress resilience in cotton.Those innovative approaches can assist cotton researchers and breeders in developing highly resilient cotton varieties capable of withstanding the challenges posed by climate change,ensuring the sustainable and prosperous future of cotton production.展开更多
Phase change material(PCM)can reduce the indoor temperature fluctuation and humidity control material can adjust relative humidity used in buildings.In this study,a kind of composite phase change material particles(CP...Phase change material(PCM)can reduce the indoor temperature fluctuation and humidity control material can adjust relative humidity used in buildings.In this study,a kind of composite phase change material particles(CPCMPs)were prepared by vacuum impregnation method with expanded perlite(EP)as supporting material and paraffin as phase change material.Thus,a PCM plate was fabricated by mould pressing method with CPCMPs and then composite phase change humidity control wallboard(CPCHCW)was prepared by spraying the diatom mud on the surface of PCM plate.The composition,thermophysical properties and microstructure were characterized using X-ray diffraction instrument(XRD),differential scanning calorimeter(DSC)and scanning electron microscope(SEM).Additionally,the hygrothermal performance of CPCHCW was characterized by temperature and humidity collaborative test.The results can be summarized as follows:(1)CPCMPs have suitable phase change parameters with melting/freezing point of 18.23°C/29.42°C and higher latent heat of 54.66 J/g/55.63 J/g;(2)the diatom mud can control the humidity of confined space with a certain volume;(3)the combination of diatom mud and PCM plate in CPCHCW can effectively adjust the indoor temperature and humidity.The above conclusions indicate the potential of CPCHCW in the application of building energy efficiency.展开更多
A binary eutectic mixture composed of tetradecanol(TD)and myristic acid(MA)was maximally absorbed into the microstructures of expanded perlite(EP)and expanded vermiculite(EVMT),respectively,through a self-made vacuum ...A binary eutectic mixture composed of tetradecanol(TD)and myristic acid(MA)was maximally absorbed into the microstructures of expanded perlite(EP)and expanded vermiculite(EVMT),respectively,through a self-made vacuum adsorption roller to prepare phase change material(PCM)particle(PCP).Then EP and EVMT-based composite PCM plates were respectively fabricated through a mold pressing method.The thermal property,chemical stability,microstructure and durability were characterized by differential scanning calorimeter(DSC),Fourier transform infrared spectroscope(FT-IR),scanning electron microscope(SEM)and thermal cycling tests,respectively.The results show that both PCPs have high latent heats with 110 J/g for EP-based PCP and more than 130 J/g for EVMT-based PCP,compact microstructure without PCM leakage,stable chemical property and good durability.The research results have proved the feasibility for the vacuum adsorption roller used in the composite PCM fabrication.Results of thermal storage performance experiment indicate that the fabricated PCM plates have better thermal inertia than common building materials,and the thermal storage performance of PCM plates has nonlinearly changed with outside air velocity and temperature increase.Therefore,PCM plates show a significant potential for the practical application of building thermal storage.展开更多
A shield machine with freezing function is proposed in order to realize tool change operation at atmospheric pressure. Furthermore, the transformation project of freezing cutterhead and tool change maintenance method ...A shield machine with freezing function is proposed in order to realize tool change operation at atmospheric pressure. Furthermore, the transformation project of freezing cutterhead and tool change maintenance method are put forward. Taking the shield construction of Huanxi Power Tunnel as an example, a numerical analysis of the freezing cutter head of the project was carried out. The results show that when the brine temperature is-25 °C, after 30 d of freezing, the thickness of the frozen wall can reach 0.67 m and the average temperature drops to-9.9 °C. When the brine temperature is-30 °C, after 50 d of freezing, the thickness of the frozen wall can reach 1.01 m and the average temperature drops to-12.4 °C. If the thickness of the frozen wall is 0.5 m and the average temperature is-10 °C, as the design index of the frozen wall, the brine temperature should be lower than-28 °C to meet the excavation requirements in 30 d. Analyzing the frozen wall stress under 0.5 m thickness and-10 °C average temperature condition, the tensile safety factor and compressive safety factor are both greater than 2 at the most dangerous position, which can meet the tool change requirements for shield construction.展开更多
Calcined ginger nuts admixed by fly ash and quartz sand(CGN-(F+S))has been validated to be basically compatible to earthen sites as an anchor grout.Accelerated ageing tests including water stability test,temperature a...Calcined ginger nuts admixed by fly ash and quartz sand(CGN-(F+S))has been validated to be basically compatible to earthen sites as an anchor grout.Accelerated ageing tests including water stability test,temperature and humidity cycling test,soundness test and alkali resistance test are conducted with the objective to further research the property changes of CGN-(F+S)grout.Density,surface hardness,water penetration capacity,water permeability capacity,soluble salt,scanning electron microscopy(SEM)images and energy dispersive spectrometry(EDS)spectrum of these samples have been tested after accelerated ageing tests.The results show that densities of samples decrease,surface hardness,water penetration capacity and water permeability capacity of samples increase generally.Besides,soluble salt analysis,SEM and EDS results well corroborate the changes.Based on the results it can be concluded that property changes are most serious after temperature and humidity cycling test,followed by water stability,soundness and alkali resistance test in sequence.But in general,CGN-(F+S)still has good durability.展开更多
Chain length of closed circle DNA is equal. The same closed circle DNA＇s position corresponds to different recognition sequence, and the same recognition sequence corresponds to different foreign DNA segment, so clos...Chain length of closed circle DNA is equal. The same closed circle DNA＇s position corresponds to different recognition sequence, and the same recognition sequence corresponds to different foreign DNA segment, so closed circle DNA computing model is generalized. For change positive-weighted Hamilton circuit problem, closed circle DNA algorithm is put forward. First, three groups of DNA encoding are encoded for all arcs, and deck groups are designed for all vertices. All possible solutions are composed. Then, the feasible solutions are filtered out by using group detect experiment, and the optimization solutions are obtained by using group insert experiment and electrophoresis experiment. Finally, all optimization solutions are found by using detect experiment. Complexity of algorithm is concluded and validity of DNA algorithm is explained by an example. Three dominances of the closed circle DNA algorithm are analyzed, and characteristics and dominances of group delete experiment are discussed.展开更多
In the present work,paraffin phase change material is used as quenchant for the heat treatment of 42CrMo4 alloy and compared with water,air,and CuO doped paraffin.The samples were prepared based on ASTM E 8M-98 standa...In the present work,paraffin phase change material is used as quenchant for the heat treatment of 42CrMo4 alloy and compared with water,air,and CuO doped paraffin.The samples were prepared based on ASTM E 8M-98 standard for tensile test and then heated up to 830°C,kept for 4 h in an electric resistance furnace and then quenched in the mentioned media.Elastic modulus,yield strength,ultimate tensile strength,elongation,and modulus of toughness were determined according to the obtained stress?strain curves.Moreover,the hardness and microstructural evolution were investigated after the heat treatment at different media.The samples quenched in paraffin and CuO-doped paraffin are higher in ultimate tensile strength(1439 and 1306 MPa,respectively)than those quenched in water(1190 MPa)and air(1010 MPa).The highest hardness,with a value of HV 552,belonged to the sample quenched in CuO-doped paraffin.The microstructural studies revealed that the non-tempered steel had a ferrite/pearlite microstructure,while by quenching in water,paraffin and CuO-doped paraffin,ferrite/martensite microstructures were achieved.It is also observed that using the air as quenchant resulted in a three-phase bainite/martensite/ferrite microstructure.展开更多
Changsha,a typical city in central China,was selected as the study area to assess the variations of ecosystem service value on the basis of land-use change. The analysis not only included the whole city but also the u...Changsha,a typical city in central China,was selected as the study area to assess the variations of ecosystem service value on the basis of land-use change. The analysis not only included the whole city but also the urban district where the landscape changed more rapidly in the center of the city. Two LANDSAT TM data sets in 1986 and 2000 and land use data of five urban districts from 1995 to 2005 were used to estimate the changes in the size of six land use categories. Meanwhile,previously published value coefficients were used to detect the changes in the value of ecosystem services delivered by each land category. The result shows that the total value of ecosystem services in Changsha declines from $1 009.28 million per year in 1986 to $938.11 million per year in 2000. This decline is largely attributable to the increase of construction land,and the conversion from woodland and water body to cropland to keep the crop production. In the five districts,there is $6.19 million decline in ecosystem service value between 1995 and 2005. Yuelu District has the highest unit ecosystem service value while Yuhua District has the lowest one. This may be attributed to the greater conversion from cropland and grassland to woodland and water body with the increase of construction land in Yuelu District. It is suggested that the increase rate of construction land should be controlled rigorously and the area of woodland and water body should be increased or at least retained in the study area.展开更多
Based on the nonlinear displacement-strain relationship,the virtual work principle method was used to establish the nonlinear equilibrium equations of steel beams with semi-rigid connections under vertical uniform loa...Based on the nonlinear displacement-strain relationship,the virtual work principle method was used to establish the nonlinear equilibrium equations of steel beams with semi-rigid connections under vertical uniform loads and temperature change.Considering the non-uniform temperature distribution across the thickness of beams,the formulas for stresses and vertical displacements were presented.On the basis of a flowchart for analysis of the numerical example,the effect of temperature change on the elastic behavior of steel beams was investigated.It is found that the maximal stress is mainly influenced by axial temperature change,and the maximal vertical displacement is principally affected by temperature gradients.And the effect of temperature gradients on the maximal vertical displacement decreases with the increase of rotational stiffness of joints.Both the maximal stress and vertical displacement decrease with the increase of rotational stiffness of joints.It can be concluded that the effects of temperature changes and rotational stiffness of joints on the elastic behavior of steel beams are significant.However,the influence of rotational stiffness becomes smaller when the rotational stiffness is larger.展开更多
In the present work,effects of various heat transfer fluids on the discharging performance of a phase change material(PCM) included cylindrical container are numerically assessed during forced convection.The heat tran...In the present work,effects of various heat transfer fluids on the discharging performance of a phase change material(PCM) included cylindrical container are numerically assessed during forced convection.The heat transfer fluid air,hydrogen,water and nanofluid with alumina particles are used and the the geometric variation of the PCM embedded region is also considered.The finite element method is used as the solver.Dynamic features of heat exchange with various phases are explored for different heat transfer fluid types,Reynolds number(between 100 and 300) and PCM embedded region geometric variation(h_(x)between 0.01 d_(1) and 0.65 d_(1),hybetween 0.1 h_(1) and 0.4 h_(1)).It is observed that discharging time is significantly influenced by the heat transfer fluid type while full phase transition time for air is obtained as more than 10 times when hydrogen is utilized as heat transfer fluid.The best performance is achieved with nanofluid.When the PCM integrated region size is reduced,discharging time is generally reduced while due to the form of the geometry,vortex formation is established in the PCM region.This results in performance degeneration at the highest radius and height of the inner cylinder.Discharging time increases by about 12% when radius of the inner cylinder is increased from h_(x)=0.35 d_(1) to h_(x)=0.45 d_(1).Dynamic features of PCM temperature and liquid fraction are affected with Reynolds number while discharging time is reduced by about 48% when configurations with the lowest and highest Reynolds number are compared.展开更多
To investigate the effects of sudden change in wind loads on the running performance of trains on the bridge in crosswinds,a highway-railway one-story bridge was taken as the research object.Aerodynamic coefficients o...To investigate the effects of sudden change in wind loads on the running performance of trains on the bridge in crosswinds,a highway-railway one-story bridge was taken as the research object.Aerodynamic coefficients of the train and the bridge were measured in a series of train-bridge system segment models through wind tunnel tests when two trains passed each other on the bridge and when a train entered and left the wind barrier section of the bridge.Based on the improved SIMPACK and ANSYS rigid-flexible coupling simulation method,a wind-double train-track-bridge system coupled vibration model was established.The dynamic responses of the train were analyzed under the effects of sudden change in wind loads caused by two trains passing each other and a train entering and leaving the wind barrier section of the bridge.The results show that the effects of sudden wind load change caused by the trains passing each other had less effects on the running safety of the leeward-side train than the wind shielding effect caused by the windward-side train in the wind speed range of 10−25 m/s.With the decrease in the porosity of wind barriers,the effects of the sudden wind load change played an increasingly important role in the running safety and comfort of the train.With the increase in wind speed,the lateral response of the train increased obviously because of the effects of sudden wind load change,which affects both the lateral running stability and the comfort of the train.展开更多
In view of the limitations of solid metal heat sink in the heat dissipation of high power light emitting diode （LED）, a kind of miniaturized phase change heat sink is developed for high power LED packaging. First, t...In view of the limitations of solid metal heat sink in the heat dissipation of high power light emitting diode （LED）, a kind of miniaturized phase change heat sink is developed for high power LED packaging. First, the fabrication process of miniaturized phase change heat sink is investigated, upon which all parts of the heat sink are fabricated including main-body and end-cover of the heat sink, the formation of three-dimensional boiling structures at the evaporation end, the sintering of the wick, and the encapsulation of high power LED phase change heat sink. Subsequently, with the assistance of the developed testing system, heat transfer performance of the heat sink is tested under the condition of natural convection, upon which the influence of thermal load and working medium on the heat transfer performance is investigated. Finally, the heat transfer performance of the developed miniaturized phase change heat sink is compared with that of metal solid heat sink. Results show that the developed miniaturized phase change heat sink presents much better heat transfer performance over traditional metal solid heat sink, and is suitable for the packaging of high power LED.展开更多
More and more attention was paid to phase change energy storage in air conditioning domain and construction energy conservation,and became the focus of the international research. Through the test and analysis of the ...More and more attention was paid to phase change energy storage in air conditioning domain and construction energy conservation,and became the focus of the international research. Through the test and analysis of the parameters of the indoor thermal property in phase change wallboard room and ordinary room,the effects of using phase change wallboards on indoor temperature in summer and air conditioning are obtained. The combination of construct enclosure and phase change materials can stabilize indoor temperature,improve indoor thermal comfort,reduce the frequency of the operation of air conditioning facility,cut the initial investment and operation expense,and meanwhile play an practical role in "the power balancing between the peak period and the valley period" policy. Through the experiment and the test of the effects exerted by phase change wallboard room and ordinary room on the indoor thermal environment,it is obtained that the phase change wallboard can reduce the fluctuation range of indoor temperature and the heat flow from the outside into indoor environment in summer. According to the study,it is found that the effect of cool-storing for 5 h is obvious. Through the analysis of the phase change wallboard without air conditioning in daytime,it is obtained that the frequency of the operation of air conditioning in phase change wallboard room is smaller than that in the ordinary room,which can prolong the lifetime of the facility and reduce operation expense.展开更多
A two-dimensional model for freezing and thawing phase change heat transfer in biological tissue embedded with two cryoprobes was established.In this model,the blood vessels were considered as tree-like branched fract...A two-dimensional model for freezing and thawing phase change heat transfer in biological tissue embedded with two cryoprobes was established.In this model,the blood vessels were considered as tree-like branched fractal network,and the effective flow rate and effective thermal conductivity of blood were obtained by fractal method.The temperature distribution and ice crystal growth process in biological tissue embedded with two cryoprobes during freezing-thawing process were numerically simulated.The results show that the growth velocity of ice crystal in freezing process from 200 to 400 s is more rapid than that from 400 to 600 s. Thawing process of frozen tissue occurs in the regions around cryoprobes tips and tissue boundary simultaneously,and the phase interfaces are close to each other until ice crystal melts completely.The distance of two cryoprobes has a more profound effect on the temperature distribution in freezing process at 400 s than at 800 s.展开更多
A kind of phase change material(PCM)-based nanocomposite was prepared and added into high energy propellants containing RDX as additives to investigate its effect on thermal decomposition and burning characteristic of...A kind of phase change material(PCM)-based nanocomposite was prepared and added into high energy propellants containing RDX as additives to investigate its effect on thermal decomposition and burning characteristic of high energy propellants.The effect of PCM-based nanocomposites on thermal decomposition of high energy propellants is investigated by TG/DSC-FTIR-MS technology.Due to the delayed protection effect(PCM-based nanocomposites can absorb lots of heat at the range of certain temperature when it undergoes structure change or phase transitions)of PCM-based nanocomposites under the thermal decomposition condition,the thermal stability of high energy propellants modified with PCMbased nanocomposites is improved.At the same time,the concentration of N2,NO2,H2O and CO_(2)is increased during thermal decomposition of high energy propellants whereas NO and CO is decreased.The burning gaseous products and burning characteristic of high energy propellants are studied by the combination of closed bomb test and Fourier transform infrared spectrum.The main burning gaseous products are N2,CO_(2),CO,H2O,CH4,etc.After the high energy propellant modified with PCM-based nanocomposites,the concentration of CH4is increased while CO,CO_(2) and H2O is decreased under the high-pressure burning condition.The progressivity factor of high energy propellants is increased by22.2%compared with the control sample while the maximum pressure is merely decreased 1.25%after the addition of the PCM-based nanocomposite,thus PCM-based nanocomposites can be used to adjust the burning process and improve the burning progressivity of high energy propellants.This study is expected to boost the practical application of PCM-based nanocomposite to the propellant formulation and effectively control the burning characteristic of high energy propellants.展开更多
In this paper, we apply the recursive genetic programming (RGP) approach to the cognition of a system, and then proceed to the detecting procedure for structural changes in the system whose components are of long memo...In this paper, we apply the recursive genetic programming (RGP) approach to the cognition of a system, and then proceed to the detecting procedure for structural changes in the system whose components are of long memory. This approach is adaptive and model-free, which can simulate the individual activities of the system's participants, therefore, it has strong ability to recognize the operating mechanism of the system. Based on the previous cognition about the system, a testing statistic is developed for the detection of structural changes in the system. Furthermore, an example is presented to illustrate the validity and practical value of the proposed.展开更多
文摘Oriented graphene aerogels have limited applica-tions because the flexibility of their graphene sheets and mi-crostructure give them a low skeleton strength,insufficient compression resilience,and poor flexibility.We report the preparation of novel aerogel materials with a much better per-formance.Using the driving force of graphene oxide(GO)self-assembly andπ-πinteractions,carbon nanotubes(CNTs)were attached to the GO sheets,and an oriented composite carbon skeleton was constructed using“hydro-plastic foam-ing”.The introduction of CNTs significantly increased the strength of the skeleton and gave the aerogel an excellent re-versible compressibility.The innovative use of cold pressing greatly improved the thermal conductivity and flexibility of the aerogel,providing new ideas for the development of high-performance aerogels.Tests show that the obtained graphene composite aerogel has a reversible compressive strain of over 90%and can withstand 500 compression cycles along the direc-tion of pore accumulation.It can endure more than 10000 bending cycles perpendicular to the direction of composite carbon layer stacking,and its in-plane thermal conductivity reaches 64.5 W·m^(-1)·K^(-1).When filled with phase change materials,the high porosity of the carbon skeleton enables the material to have a high phase change filling rate,and its phase change enthalpy is greater than 150 J/g.Thanks to the exceptional flexibility of the carbon skeleton,the macrostructure of phase change materials can be bent as needed to adapt to thermal management scenarios and conform to device shapes.This significantly enhances practical application compatibility,providing flexible support for temperature control and thermal management across diverse device forms.
文摘Objective Primary liver cancer,predominantly hepatocellular carcinoma(HCC),is a significant global health issue,ranking as the sixth most diagnosed cancer and the third leading cause of cancer-related mortality.Accurate and early diagnosis of HCC is crucial for effective treatment,as HCC and non-HCC malignancies like intrahepatic cholangiocarcinoma(ICC)exhibit different prognoses and treatment responses.Traditional diagnostic methods,including liver biopsy and contrast-enhanced ultrasound(CEUS),face limitations in applicability and objectivity.The primary objective of this study was to develop an advanced,lightweighted classification network capable of distinguishing HCC from other non-HCC malignancies by leveraging the automatic analysis of brightness changes in CEUS images.The ultimate goal was to create a user-friendly and cost-efficient computer-aided diagnostic tool that could assist radiologists in making more accurate and efficient clinical decisions.Methods This retrospective study encompassed a total of 161 patients,comprising 131 diagnosed with HCC and 30 with non-HCC malignancies.To achieve accurate tumor detection,the YOLOX network was employed to identify the region of interest(ROI)on both B-mode ultrasound and CEUS images.A custom-developed algorithm was then utilized to extract brightness change curves from the tumor and adjacent liver parenchyma regions within the CEUS images.These curves provided critical data for the subsequent analysis and classification process.To analyze the extracted brightness change curves and classify the malignancies,we developed and compared several models.These included one-dimensional convolutional neural networks(1D-ResNet,1D-ConvNeXt,and 1D-CNN),as well as traditional machine-learning methods such as support vector machine(SVM),ensemble learning(EL),k-nearest neighbor(KNN),and decision tree(DT).The diagnostic performance of each method in distinguishing HCC from non-HCC malignancies was rigorously evaluated using four key metrics:area under the receiver operating characteristic(AUC),accuracy(ACC),sensitivity(SE),and specificity(SP).Results The evaluation of the machine-learning methods revealed AUC values of 0.70 for SVM,0.56 for ensemble learning,0.63 for KNN,and 0.72 for the decision tree.These results indicated moderate to fair performance in classifying the malignancies based on the brightness change curves.In contrast,the deep learning models demonstrated significantly higher AUCs,with 1D-ResNet achieving an AUC of 0.72,1D-ConvNeXt reaching 0.82,and 1D-CNN obtaining the highest AUC of 0.84.Moreover,under the five-fold cross-validation scheme,the 1D-CNN model outperformed other models in both accuracy and specificity.Specifically,it achieved accuracy improvements of 3.8%to 10.0%and specificity enhancements of 6.6%to 43.3%over competing approaches.The superior performance of the 1D-CNN model highlighted its potential as a powerful tool for accurate classification.Conclusion The 1D-CNN model proved to be the most effective in differentiating HCC from non-HCC malignancies,surpassing both traditional machine-learning methods and other deep learning models.This study successfully developed a user-friendly and cost-efficient computer-aided diagnostic solution that would significantly enhances radiologists’diagnostic capabilities.By improving the accuracy and efficiency of clinical decision-making,this tool has the potential to positively impact patient care and outcomes.Future work may focus on further refining the model and exploring its integration with multimodal ultrasound data to maximize its accuracy and applicability.
基金supported by major national R&D projects(No.2023ZD04040-01)National Natural Science Foundation of China(No.5201101621)National Key R&D Plan(No.2022YFD1200304).
文摘Cotton is an essential agricultural commodity,but its global yield is greatly affected by climate change,which poses a serious threat to the agriculture sector.This review aims to provide an overview of the impact of climate change on cotton production and the use of genomic approaches to increase stress tolerance in cotton.This paper discusses the effects of rising temperatures,changing precipitation patterns,and extreme weather events on cotton yield.It then explores various genomic strategies,such as genomic selection and marker-assisted selection,which can be used to develop stress-tolerant cotton varieties.The review emphasizes the need for interdisciplinary research efforts and policy interventions to mitigate the adverse effects of climate change on cotton production.Furthermore,this paper presents advanced prospects,including genomic selection,gene editing,multi-omics integration,highthroughput phenotyping,genomic data sharing,climate-informed breeding,and phenomics-assisted genomic selection,for enhancing stress resilience in cotton.Those innovative approaches can assist cotton researchers and breeders in developing highly resilient cotton varieties capable of withstanding the challenges posed by climate change,ensuring the sustainable and prosperous future of cotton production.
基金Project(51408184)supported by the National Natural Science Foundation of ChinaProject(E2017202136)supported by the Natural Science Foundation of Hebei Province,China+1 种基金Project(BSBE2017-05)supported by the Opening Funds of State Key Laboratory of Building Safety and Built Environment and National Engineering Research Center of Building Technology,ChinaProject(QG2018-3)supported by Hebei Provincial Department of Transportation,China
文摘Phase change material(PCM)can reduce the indoor temperature fluctuation and humidity control material can adjust relative humidity used in buildings.In this study,a kind of composite phase change material particles(CPCMPs)were prepared by vacuum impregnation method with expanded perlite(EP)as supporting material and paraffin as phase change material.Thus,a PCM plate was fabricated by mould pressing method with CPCMPs and then composite phase change humidity control wallboard(CPCHCW)was prepared by spraying the diatom mud on the surface of PCM plate.The composition,thermophysical properties and microstructure were characterized using X-ray diffraction instrument(XRD),differential scanning calorimeter(DSC)and scanning electron microscope(SEM).Additionally,the hygrothermal performance of CPCHCW was characterized by temperature and humidity collaborative test.The results can be summarized as follows:(1)CPCMPs have suitable phase change parameters with melting/freezing point of 18.23°C/29.42°C and higher latent heat of 54.66 J/g/55.63 J/g;(2)the diatom mud can control the humidity of confined space with a certain volume;(3)the combination of diatom mud and PCM plate in CPCHCW can effectively adjust the indoor temperature and humidity.The above conclusions indicate the potential of CPCHCW in the application of building energy efficiency.
基金Project(51408184)supported by the National Natural Science Foundation of ChinaProject(E2017202136)supported by the Natural Science Foundation of Hebei Province,China+1 种基金Project(BSBE2017-05)supported by Opening Funds of State Key Laboratory of Building Safety and Built Environment and National Engineering Research Center of Building Technology,ChinaProject(QG2018-3)supported by Hebei Provincial Department of Transportation,China
文摘A binary eutectic mixture composed of tetradecanol(TD)and myristic acid(MA)was maximally absorbed into the microstructures of expanded perlite(EP)and expanded vermiculite(EVMT),respectively,through a self-made vacuum adsorption roller to prepare phase change material(PCM)particle(PCP).Then EP and EVMT-based composite PCM plates were respectively fabricated through a mold pressing method.The thermal property,chemical stability,microstructure and durability were characterized by differential scanning calorimeter(DSC),Fourier transform infrared spectroscope(FT-IR),scanning electron microscope(SEM)and thermal cycling tests,respectively.The results show that both PCPs have high latent heats with 110 J/g for EP-based PCP and more than 130 J/g for EVMT-based PCP,compact microstructure without PCM leakage,stable chemical property and good durability.The research results have proved the feasibility for the vacuum adsorption roller used in the composite PCM fabrication.Results of thermal storage performance experiment indicate that the fabricated PCM plates have better thermal inertia than common building materials,and the thermal storage performance of PCM plates has nonlinearly changed with outside air velocity and temperature increase.Therefore,PCM plates show a significant potential for the practical application of building thermal storage.
基金Project(2014FJ1002)supported by the Science and Technology Major Project of Hunan Province,ChinaProject(2012AA041803)supported by National High Technology Research and Development Program of China。
文摘A shield machine with freezing function is proposed in order to realize tool change operation at atmospheric pressure. Furthermore, the transformation project of freezing cutterhead and tool change maintenance method are put forward. Taking the shield construction of Huanxi Power Tunnel as an example, a numerical analysis of the freezing cutter head of the project was carried out. The results show that when the brine temperature is-25 °C, after 30 d of freezing, the thickness of the frozen wall can reach 0.67 m and the average temperature drops to-9.9 °C. When the brine temperature is-30 °C, after 50 d of freezing, the thickness of the frozen wall can reach 1.01 m and the average temperature drops to-12.4 °C. If the thickness of the frozen wall is 0.5 m and the average temperature is-10 °C, as the design index of the frozen wall, the brine temperature should be lower than-28 °C to meet the excavation requirements in 30 d. Analyzing the frozen wall stress under 0.5 m thickness and-10 °C average temperature condition, the tensile safety factor and compressive safety factor are both greater than 2 at the most dangerous position, which can meet the tool change requirements for shield construction.
基金Project(51578272)supported by the National Natural Science Foundation of China
文摘Calcined ginger nuts admixed by fly ash and quartz sand(CGN-(F+S))has been validated to be basically compatible to earthen sites as an anchor grout.Accelerated ageing tests including water stability test,temperature and humidity cycling test,soundness test and alkali resistance test are conducted with the objective to further research the property changes of CGN-(F+S)grout.Density,surface hardness,water penetration capacity,water permeability capacity,soluble salt,scanning electron microscopy(SEM)images and energy dispersive spectrometry(EDS)spectrum of these samples have been tested after accelerated ageing tests.The results show that densities of samples decrease,surface hardness,water penetration capacity and water permeability capacity of samples increase generally.Besides,soluble salt analysis,SEM and EDS results well corroborate the changes.Based on the results it can be concluded that property changes are most serious after temperature and humidity cycling test,followed by water stability,soundness and alkali resistance test in sequence.But in general,CGN-(F+S)still has good durability.
基金supported by the National Natural Science Foundation of China(60574041)the Natural ScienceFoundation of Hubei Province(2007ABA407).
文摘Chain length of closed circle DNA is equal. The same closed circle DNA＇s position corresponds to different recognition sequence, and the same recognition sequence corresponds to different foreign DNA segment, so closed circle DNA computing model is generalized. For change positive-weighted Hamilton circuit problem, closed circle DNA algorithm is put forward. First, three groups of DNA encoding are encoded for all arcs, and deck groups are designed for all vertices. All possible solutions are composed. Then, the feasible solutions are filtered out by using group detect experiment, and the optimization solutions are obtained by using group insert experiment and electrophoresis experiment. Finally, all optimization solutions are found by using detect experiment. Complexity of algorithm is concluded and validity of DNA algorithm is explained by an example. Three dominances of the closed circle DNA algorithm are analyzed, and characteristics and dominances of group delete experiment are discussed.
文摘In the present work,paraffin phase change material is used as quenchant for the heat treatment of 42CrMo4 alloy and compared with water,air,and CuO doped paraffin.The samples were prepared based on ASTM E 8M-98 standard for tensile test and then heated up to 830°C,kept for 4 h in an electric resistance furnace and then quenched in the mentioned media.Elastic modulus,yield strength,ultimate tensile strength,elongation,and modulus of toughness were determined according to the obtained stress?strain curves.Moreover,the hardness and microstructural evolution were investigated after the heat treatment at different media.The samples quenched in paraffin and CuO-doped paraffin are higher in ultimate tensile strength(1439 and 1306 MPa,respectively)than those quenched in water(1190 MPa)and air(1010 MPa).The highest hardness,with a value of HV 552,belonged to the sample quenched in CuO-doped paraffin.The microstructural studies revealed that the non-tempered steel had a ferrite/pearlite microstructure,while by quenching in water,paraffin and CuO-doped paraffin,ferrite/martensite microstructures were achieved.It is also observed that using the air as quenchant resulted in a three-phase bainite/martensite/ferrite microstructure.
基金Project(hdzy0903) supported by Hunan University Ability Training Program by the Basic Operation Costs of Central Colleges and Universities for Scientific Research
文摘Changsha,a typical city in central China,was selected as the study area to assess the variations of ecosystem service value on the basis of land-use change. The analysis not only included the whole city but also the urban district where the landscape changed more rapidly in the center of the city. Two LANDSAT TM data sets in 1986 and 2000 and land use data of five urban districts from 1995 to 2005 were used to estimate the changes in the size of six land use categories. Meanwhile,previously published value coefficients were used to detect the changes in the value of ecosystem services delivered by each land category. The result shows that the total value of ecosystem services in Changsha declines from $1 009.28 million per year in 1986 to $938.11 million per year in 2000. This decline is largely attributable to the increase of construction land,and the conversion from woodland and water body to cropland to keep the crop production. In the five districts,there is $6.19 million decline in ecosystem service value between 1995 and 2005. Yuelu District has the highest unit ecosystem service value while Yuhua District has the lowest one. This may be attributed to the greater conversion from cropland and grassland to woodland and water body with the increase of construction land in Yuelu District. It is suggested that the increase rate of construction land should be controlled rigorously and the area of woodland and water body should be increased or at least retained in the study area.
基金Project(50478075) supported by the National Natural Science Foundation of ChinaProject(YBJJ0817) supported by Scientific Research Foundation of Graduate School of Southeast University
文摘Based on the nonlinear displacement-strain relationship,the virtual work principle method was used to establish the nonlinear equilibrium equations of steel beams with semi-rigid connections under vertical uniform loads and temperature change.Considering the non-uniform temperature distribution across the thickness of beams,the formulas for stresses and vertical displacements were presented.On the basis of a flowchart for analysis of the numerical example,the effect of temperature change on the elastic behavior of steel beams was investigated.It is found that the maximal stress is mainly influenced by axial temperature change,and the maximal vertical displacement is principally affected by temperature gradients.And the effect of temperature gradients on the maximal vertical displacement decreases with the increase of rotational stiffness of joints.Both the maximal stress and vertical displacement decrease with the increase of rotational stiffness of joints.It can be concluded that the effects of temperature changes and rotational stiffness of joints on the elastic behavior of steel beams are significant.However,the influence of rotational stiffness becomes smaller when the rotational stiffness is larger.
文摘In the present work,effects of various heat transfer fluids on the discharging performance of a phase change material(PCM) included cylindrical container are numerically assessed during forced convection.The heat transfer fluid air,hydrogen,water and nanofluid with alumina particles are used and the the geometric variation of the PCM embedded region is also considered.The finite element method is used as the solver.Dynamic features of heat exchange with various phases are explored for different heat transfer fluid types,Reynolds number(between 100 and 300) and PCM embedded region geometric variation(h_(x)between 0.01 d_(1) and 0.65 d_(1),hybetween 0.1 h_(1) and 0.4 h_(1)).It is observed that discharging time is significantly influenced by the heat transfer fluid type while full phase transition time for air is obtained as more than 10 times when hydrogen is utilized as heat transfer fluid.The best performance is achieved with nanofluid.When the PCM integrated region size is reduced,discharging time is generally reduced while due to the form of the geometry,vortex formation is established in the PCM region.This results in performance degeneration at the highest radius and height of the inner cylinder.Discharging time increases by about 12% when radius of the inner cylinder is increased from h_(x)=0.35 d_(1) to h_(x)=0.45 d_(1).Dynamic features of PCM temperature and liquid fraction are affected with Reynolds number while discharging time is reduced by about 48% when configurations with the lowest and highest Reynolds number are compared.
基金Projects(51822803,51878080,51778073) supported by the National Natural Science Foundation of ChinaProjects(2020JJ3035,2018JJ3538) supported by the Hunan Provincial Natural Science Foundation of China。
文摘To investigate the effects of sudden change in wind loads on the running performance of trains on the bridge in crosswinds,a highway-railway one-story bridge was taken as the research object.Aerodynamic coefficients of the train and the bridge were measured in a series of train-bridge system segment models through wind tunnel tests when two trains passed each other on the bridge and when a train entered and left the wind barrier section of the bridge.Based on the improved SIMPACK and ANSYS rigid-flexible coupling simulation method,a wind-double train-track-bridge system coupled vibration model was established.The dynamic responses of the train were analyzed under the effects of sudden change in wind loads caused by two trains passing each other and a train entering and leaving the wind barrier section of the bridge.The results show that the effects of sudden wind load change caused by the trains passing each other had less effects on the running safety of the leeward-side train than the wind shielding effect caused by the windward-side train in the wind speed range of 10−25 m/s.With the decrease in the porosity of wind barriers,the effects of the sudden wind load change played an increasingly important role in the running safety and comfort of the train.With the increase in wind speed,the lateral response of the train increased obviously because of the effects of sudden wind load change,which affects both the lateral running stability and the comfort of the train.
基金Projects(51575115,51775122)supported by the National Natural Science Foundation of China
文摘In view of the limitations of solid metal heat sink in the heat dissipation of high power light emitting diode （LED）, a kind of miniaturized phase change heat sink is developed for high power LED packaging. First, the fabrication process of miniaturized phase change heat sink is investigated, upon which all parts of the heat sink are fabricated including main-body and end-cover of the heat sink, the formation of three-dimensional boiling structures at the evaporation end, the sintering of the wick, and the encapsulation of high power LED phase change heat sink. Subsequently, with the assistance of the developed testing system, heat transfer performance of the heat sink is tested under the condition of natural convection, upon which the influence of thermal load and working medium on the heat transfer performance is investigated. Finally, the heat transfer performance of the developed miniaturized phase change heat sink is compared with that of metal solid heat sink. Results show that the developed miniaturized phase change heat sink presents much better heat transfer performance over traditional metal solid heat sink, and is suitable for the packaging of high power LED.
基金Project(50878133) supported by the National Natural Science Foundation of ChinaProject(2007R37) supported by the Program Supporting Excellent Talents of Liaoning Province,China+1 种基金Project(2008S193) supported by the Key Laboratory Fund of Education Department of Liaoning Province,ChinaProject(1071211-1-00) supported by the Scientific and Technical Fund Project Subsidy of Shenyang,China
文摘More and more attention was paid to phase change energy storage in air conditioning domain and construction energy conservation,and became the focus of the international research. Through the test and analysis of the parameters of the indoor thermal property in phase change wallboard room and ordinary room,the effects of using phase change wallboards on indoor temperature in summer and air conditioning are obtained. The combination of construct enclosure and phase change materials can stabilize indoor temperature,improve indoor thermal comfort,reduce the frequency of the operation of air conditioning facility,cut the initial investment and operation expense,and meanwhile play an practical role in "the power balancing between the peak period and the valley period" policy. Through the experiment and the test of the effects exerted by phase change wallboard room and ordinary room on the indoor thermal environment,it is obtained that the phase change wallboard can reduce the fluctuation range of indoor temperature and the heat flow from the outside into indoor environment in summer. According to the study,it is found that the effect of cool-storing for 5 h is obvious. Through the analysis of the phase change wallboard without air conditioning in daytime,it is obtained that the frequency of the operation of air conditioning in phase change wallboard room is smaller than that in the ordinary room,which can prolong the lifetime of the facility and reduce operation expense.
基金Project(50436030)supported by the National Natural Science Foundation of China
文摘A two-dimensional model for freezing and thawing phase change heat transfer in biological tissue embedded with two cryoprobes was established.In this model,the blood vessels were considered as tree-like branched fractal network,and the effective flow rate and effective thermal conductivity of blood were obtained by fractal method.The temperature distribution and ice crystal growth process in biological tissue embedded with two cryoprobes during freezing-thawing process were numerically simulated.The results show that the growth velocity of ice crystal in freezing process from 200 to 400 s is more rapid than that from 400 to 600 s. Thawing process of frozen tissue occurs in the regions around cryoprobes tips and tissue boundary simultaneously,and the phase interfaces are close to each other until ice crystal melts completely.The distance of two cryoprobes has a more profound effect on the temperature distribution in freezing process at 400 s than at 800 s.
基金the National Natural Science Foundation of China(Grant No.22075146)to provide fund for conducting experiments。
文摘A kind of phase change material(PCM)-based nanocomposite was prepared and added into high energy propellants containing RDX as additives to investigate its effect on thermal decomposition and burning characteristic of high energy propellants.The effect of PCM-based nanocomposites on thermal decomposition of high energy propellants is investigated by TG/DSC-FTIR-MS technology.Due to the delayed protection effect(PCM-based nanocomposites can absorb lots of heat at the range of certain temperature when it undergoes structure change or phase transitions)of PCM-based nanocomposites under the thermal decomposition condition,the thermal stability of high energy propellants modified with PCMbased nanocomposites is improved.At the same time,the concentration of N2,NO2,H2O and CO_(2)is increased during thermal decomposition of high energy propellants whereas NO and CO is decreased.The burning gaseous products and burning characteristic of high energy propellants are studied by the combination of closed bomb test and Fourier transform infrared spectrum.The main burning gaseous products are N2,CO_(2),CO,H2O,CH4,etc.After the high energy propellant modified with PCM-based nanocomposites,the concentration of CH4is increased while CO,CO_(2) and H2O is decreased under the high-pressure burning condition.The progressivity factor of high energy propellants is increased by22.2%compared with the control sample while the maximum pressure is merely decreased 1.25%after the addition of the PCM-based nanocomposite,thus PCM-based nanocomposites can be used to adjust the burning process and improve the burning progressivity of high energy propellants.This study is expected to boost the practical application of PCM-based nanocomposite to the propellant formulation and effectively control the burning characteristic of high energy propellants.
文摘In this paper, we apply the recursive genetic programming (RGP) approach to the cognition of a system, and then proceed to the detecting procedure for structural changes in the system whose components are of long memory. This approach is adaptive and model-free, which can simulate the individual activities of the system's participants, therefore, it has strong ability to recognize the operating mechanism of the system. Based on the previous cognition about the system, a testing statistic is developed for the detection of structural changes in the system. Furthermore, an example is presented to illustrate the validity and practical value of the proposed.
