The remarkable ability of titanium alloys to preserve their superior physical and chemical characteristics when subjected to extreme conditions significantly enhances their importance in the aerospace,military,and med...The remarkable ability of titanium alloys to preserve their superior physical and chemical characteristics when subjected to extreme conditions significantly enhances their importance in the aerospace,military,and medical sectors.However,conventional machining of titanium alloys leads to elevated tool wear,development of surface defects,and reduced machining efficiency due to their low heat conductivity,and chemical affinity.These issues can be somewhat counteracted by integrating ultrasonic vibration in the conventional machining of titanium alloys and also enhance sustainability.This review article offers a holistic evaluation of the influence of ultrasonic vibration-assisted milling and turning on cutting forces,temperature,tool wear,and surface integrity,encompassing surface morphology,surface roughness,surface residual stress,surface hardness,and surface tribological properties during titanium alloys machining.Furthermore,it investigates the sustainability aspect that has not been previously examined.Studies on the performance of ultrasonic-assisted cutting revealed several advantages,including decreased cutting forces and cutting temperature,improved tool life,and a better-machined surface during machining.Consequently,the sustainability factor is improved due to minimized energy consumption and residual waste.In conclusion,the key challenges and future prospects in the ultrasonic-assisted cutting of titanium alloys are also discussed.This review article provides beneficial knowledge for manufactur-ers and researchers regarding ultrasonic vibration-assisted cutting of titanium alloy and will play an important role in achieving sustainability in the industry.展开更多
【目的】基于猪极端饲料报酬表型,利用靶向切割标签技术(cleavage under targets and tagmentation,CUT&Tag)构建H3K27ac差异图谱,鉴定关联的启动子、增强子和关联候选基因,为猪饲料报酬解析提供基础数据。【方法】从209头杜洛克猪...【目的】基于猪极端饲料报酬表型,利用靶向切割标签技术(cleavage under targets and tagmentation,CUT&Tag)构建H3K27ac差异图谱,鉴定关联的启动子、增强子和关联候选基因,为猪饲料报酬解析提供基础数据。【方法】从209头杜洛克猪中筛选饲料报酬表型差异最大的4头个体分别组成低剩余采食量组(L组,n=2)和高剩余采食量组(H组,n=2)。利用CUT&Tag技术,以H3K27ac作为活性启动子和增强子的表观遗传标记对4头个体的肝脏组织进行全基因组扫描,鉴定关联启动子、增强子和候选基因,并进一步采用real-time quantitative PCR(RT-qPCR)对重要基因进行验证。【结果】共鉴定出47271个H3K27ac峰,包括15739个潜在启动子和31532个推定增强子,大部分的H3K27ac峰位于近端启动子区域。根据H3K27ac全基因的分布情况和作用特点,发现3087个差异峰(对应2188个基因),其中867个H3K27ac峰(对应664个基因)富集在H组,2220个H3K27ac峰(对应1575个基因)富集在L组。GO和KEGG结果发现H3K27ac增强子可能是通过影响胆汁酸代谢、淋巴细胞代谢和NF-κB通路来调节饲料报酬。RT-qPCR结果显示,与H组相比,DIAPH3、DPYD、FTO、TCF7L2、ABCC2、ABCC11、RXRA和ABCG8在L组中显著上调(P<0.05),而PAX5、GRHPR、NFATC1、CARD11、BLNK和LYN在L组中显著下调(P<0.05)。【结论】本研究成功生成了具有极端RFI差异的杜洛克猪肝脏组织中的H3K27ac差异图谱以及相关数据。基于该图谱鉴定和验证了关联候选基因,为进一步解析启动子和增强子调控饲料报酬的分子机制提供了基础数据。展开更多
China has a history of more than five thousand years,and its culture is broad and rich.Among many traditional arts,paper-cutting is a special handicraft full of stories and myths.Paper-cutting is a unique art.People u...China has a history of more than five thousand years,and its culture is broad and rich.Among many traditional arts,paper-cutting is a special handicraft full of stories and myths.Paper-cutting is a unique art.People use scissors to cut paper into many beautiful shapes,such as flowers,animals,or people.This art only needs simple tools,but it is not as easy as it looks.When we watch the masters cut paper,they can create wonderful patterns in just a few minutes.However,for beginners,a lot of practice and patience are necessary.展开更多
With the widespread adoption of ultra-precision machining(UPM)in manufacturing,accurately monitoring the temperature within micro-scale cutting zones has become crucial for ensuring machining quality and tool longevit...With the widespread adoption of ultra-precision machining(UPM)in manufacturing,accurately monitoring the temperature within micro-scale cutting zones has become crucial for ensuring machining quality and tool longevity.This review comprehensively evaluates modern in-process cutting temperature measurement methods,comparing conventional approaches and emerging technologies.Thermal conduction-based and radiation-based measurement paradigms are analyzed in terms of their merits,limitations,and domain-specific applicability,particularly with regard to the unique challenges involving micro-scale cutting zones in UPM.Special emphasis is placed on micro-scale sensor-integrated tools and self-sensing tools that enable real-time thermal monitoring at cutting edges.Furthermore,we explore thermal monitoring and management techniques for atomic and close-to-atomic scale manufacturing(ACSM),as well as the transformative potential of emerging technologies like artificial intelligence(AI),internet of things(IoT),and data fusion for machining temperature measurement.This review may serve as a reference for UPM cutting temperature measurement research,helping foster the development of optimized process control technologies.展开更多
A centrifugal pump with a specific speed ns=67 is considered in this study to investigate the impact of blade cutting(at the outlet edge)on the fluid-induced noise,while keeping all the other geometric parameters unch...A centrifugal pump with a specific speed ns=67 is considered in this study to investigate the impact of blade cutting(at the outlet edge)on the fluid-induced noise,while keeping all the other geometric parameters unchanged.The required unsteady numerical calculations are conducted by applying the RNG k-εturbulence model with the volute dipole being used as the sound source.The results indicate that the internal pressure energy of the centrifugal pump essentially depends on the blade passing frequency and its low-frequency harmonic frequency.Moreover,the pressure pulsation distribution directly affects the noise caused by the centrifugal pump.The sound pressure inside and outside the centrifugal pump and the sound power at the blade passing frequency gradually decrease increasing cutting distance of the impeller blades.When the cutting percentage is 1.21%,that is,the clearance ratio between impeller blade and tongue is 8.57%,the comprehensive performance of the centrifugal pump is the best.展开更多
Drill cuttings,though rarely used,are crucial subsurface samples to understand petrographic properties affecting reservoir quality.Unlike core material,cuttings are continuously available along the wellbore and can be...Drill cuttings,though rarely used,are crucial subsurface samples to understand petrographic properties affecting reservoir quality.Unlike core material,cuttings are continuously available along the wellbore and can be used during drilling to monitor progress.Therefore,cuttings may allow a semi-quantitative,statistical calibration of rock properties from the subsurface,but they are often underutilized.Although fracture and vein orientations cannot be reconstructed from drill cuttings,the presence of veins and their internal textures(open,partially sealed or sealed) in specific formation sections and depths can be identified and analyzed using e.g.,transmitted light microscopy and cathodoluminescence to supplement characterization at the well site and subsequently assess production behavior.Borehole gamma ray logs in combination with handheld portable X-ray fluorescence(pXRF) analyses on cleaned and dried drill cuttings can be used to further improve the depth accuracy of the cutting samples and to geochemically fingerprint the samples,based on the Si/Al ratio,as a proxy for sandstone-rich and mudrock-rich sections of the well.In this study,eighty-three sandstone cutting samples from two wells,covering~400 m of stratigraphy targeting the Paleocene-Eocene Greifenstein Fm.equivalent(Glauconite Sandstone,GLS) in the Vienna Basin(Austria),were studied.They also cover parts of three different reservoir sections(1.to 3.GLS).The Flysch play in the Vienna Basin hosts several sand stone-mud rock interbeds and is composed of several nappes,forming complex reservoir compartments.The glauconite contents vary between different sections of the GLS,where the highest is observed in the 3.GLS.The sandstones are predominantly cemented by ferroan calcite,resulting in low optical porosity(<5 %)in both wells,with only individually elevated porosity,related to partially dissolved K-feldspar grains.A paragenetic sequence solely based on cuttings further highlights that reservoir quality in the studied section is independent of sandstone compaction,but is related to lower optical porosity in finer-grained sa ndstones and higher carbonate vein cement conte nts.Furthermo re,productive intervals are related to lower Fe+Mg contents.The understanding of reservoir properties,diagenesis,and their influence on fluid flow is crucial for successful exploration and reduction of uncertainty in reservoir production and development.The diagenetic variations from cuttings and the geochemical fingerprint by pXRF are linked to reservoir quality and production performance of individual well perforations.This approach can provide additional information on reservoir quality where core material is unavailable.展开更多
To meet the demand for the machining of blisks with narrow cascade channels and twisted blade profiles,especially integral shrouded blisks with shrouds,this paper innovatively proposes a method for dynamic deformation...To meet the demand for the machining of blisks with narrow cascade channels and twisted blade profiles,especially integral shrouded blisks with shrouds,this paper innovatively proposes a method for dynamic deformation electrochemical cutting of flexible electrodes with arrayed group slit structure.By applying torque to both ends of the flexible electrode,the proposed method produces bending deformation and realizes the processing of a twisted profile.The flexible electrode is an important carrier of this method,and its properties such as elasticity,rigidity,and flow field uniformity have a crucial impact on smooth processing.Therefore,this paper proposes a design theory of flexible electrodes with an arrayed group slit structure and designs flexible electrodes with variable cross-sections.Compared with traditional uniform section tube electrode,the designed flexible electrode was subjected to the corresponding mechanical simulation,flow field simulation,and fluid–structure interaction simulation to investigate the elasticity,rigidity,and flow field uniformity of the flexible electrode.In addition,a deformation device of flexible electrodes was constructed and the corresponding experiments were carried out.Simulations and experiments demonstrate that flexible electrodes with arrayed group slit structures have good comprehensive performance.Finally,typical components were successfully machined to verify the feasibility of the proposed method and the rationality of the designed flexible electrode.It is shown that the proposed method has great potential for the machining of distorted profiles and provides a new idea for the machining of complex profiles.展开更多
During the excavation process of deep hard rock tunnels,precutting rock with an abrasive water jet can weaken their strength and improve the efficiency of mining machinery.However,owing to the complex geological envir...During the excavation process of deep hard rock tunnels,precutting rock with an abrasive water jet can weaken their strength and improve the efficiency of mining machinery.However,owing to the complex geological environment,abrasive jets cannot fully utilize their rock-cutting performance.To fully exploit the advantages of high-pressure abrasive water jets,five orthogonal experiments were designed for rocks with significant differences in strength.Experimental research has been conducted on the performance of rotating abrasive waterjet-cutting rocks.Moreover,a neural network prediction model for predicting rock-cutting characteristics is established by comprehensively considering rock mechanics parameters and abrasive water jet parameters.The results show that the cutting depth of rocks with different strengths increases nonlinearly with increasing work pressure of the abrasive water jet.The cutting depth decreases exponentially with increasing cutting velocity.The cutting depth first increases and then decreases with increasing target distance,and the best target distance is between 4 mm and 6 mm.The effect of the target distance on the cutting width of rock is the most significant,but the cutting width of high-strength rock is not sensitive to changes in the working parameters of the abrasive water jet.The average relative errors of BP(backpropagation)neural networks optimized by global optimization algorithms in predicting rock cutting depth and width are 13.3%and 5.4%,respectively.This research combines the working characteristics of mining machinery to study the performance of abrasive waterjet rotary cutting of rocks and constructs a predictive model for the performance of abrasive waterjet cutting of rocks that includes rock strength factors.This provides a new solution for quickly adjusting the working parameters of abrasive water jets according to mining conditions.展开更多
The water content of cut flowers is a significant factor in their post-harvest quality.In this study,we examine the efficacy of silver nanoparticles(NS)on the longevity of cut gladiolus,with a focus on water state and...The water content of cut flowers is a significant factor in their post-harvest quality.In this study,we examine the efficacy of silver nanoparticles(NS)on the longevity of cut gladiolus,with a focus on water state and distribution.We used Low-field nuclear magnetic resonance(LF-NMR)technology to identify three water fractions with different transverse relaxation times(T2)values:bound water T21(<10 ms),intermediate immobilized water T22(10-100 ms),and the slowest component free water T23(>10 ms).During the opening process,T23increased at stages 2 and 3 and then decreased,T22 decreased slowly,and T21 remained unchanged.Free water values were consistently higher than bound water and immobilized water and reached their maximum from stage 2 until stage 4,when the petals were extended and began to wilt.The vascular bundles responsible for transporting water had higher water content,as detected by proton density-weighted magnetic resonance imaging(MRI).Bound water and free water with NS pretreatments in bracts were initially lower but then two days later the signal amplitude of each water state exceeded those of the control,indicating that the treatment enhanced the water-holding capacity over time.Furthermore,NS pretreatments reduced the free water mobility of the cut flowers and inhibited stem decay.Additionally,we found that NS can enter the stem and are primarily transported upward along the xylem with water using scanning electron microscopy(SEM)and energy-dispersive X-ray spectroscopy(EDS)technology.Overall,our findings indicate that NS pretreatment reduces free water in gladiolus cut flowers,enhancing their water retention and prolonging their vase life.展开更多
Real-time identification of rock strength and cuttability based on monitoring while cutting during excavation is essential for key procedures such as the precise adjustment of excavation parameters and the in-situ mod...Real-time identification of rock strength and cuttability based on monitoring while cutting during excavation is essential for key procedures such as the precise adjustment of excavation parameters and the in-situ modification of hard rocks.This study proposes an in-telligent approach for predicting rock strength and cuttability.A database comprising 132 data sets is established,containing cutting para-meters(such as cutting depth and pick angle),cutting responses(such as specific energy and instantaneous cutting rate),and rock mech-anical parameters collected from conical pick-cutting experiments.These parameters serve as input features for predicting the uniaxial compressive strength and tensile strength of rocks using regression fitting and machine learning methodologies.In addition,rock cuttabil-ity is classified using a combination of the analytic hierarchy process and fuzzy comprehensive evaluation method,and subsequently iden-tified through machine learning approaches.Various models are compared to determine the optimal predictive and classification models.The results indicate that the optimal model for uniaxial compressive strength and tensile strength prediction is the genetic algorithm-optimized backpropagation neural network model,and the optimal model for rock cuttability classification is the radial basis neural network model.展开更多
Kirigami,through introducing cuts into a thin sheet,can greatly improve the stretchability of structures and also generate complex patterns,showing potentials in various applications.Interestingly,even with the same c...Kirigami,through introducing cuts into a thin sheet,can greatly improve the stretchability of structures and also generate complex patterns,showing potentials in various applications.Interestingly,even with the same cutting pattern,the mechanical response of kirigami metamaterials can exhibit significant differences depending on the cutting angles in respect to the loading direction.In this work,we investigate the structural deformation of kirigami metamaterials with square domains and varied cutting angles of 0°and 45°.We further introduce a second level of cutting on the basis of the first cutting pattern.By combining experiments and finite element simulations,it is found that,compared to the commonly used 0°cuts,the two-level kirigami metamaterials with 45°cuts exhibit a unique alternating arrangement phenomenon of expanded/unexpanded states in the loading process,which also results in distinct stress–strain response.Through tuning the cutting patterns of metamaterials with 45°cuts,precise control of the rotation of the kirigami unit is realized,leading to kirigami metamaterials with encryption properties.The current work demonstrates the programmability of structural deformation in hierarchical kirigami metamaterials through controlling the local cutting modes.展开更多
The water conductivity of karst collapsed column is affected by multiple factors such as the characteristics of its own column filling,structure and mining disturbance.As a structural water-conducting channel,fault us...The water conductivity of karst collapsed column is affected by multiple factors such as the characteristics of its own column filling,structure and mining disturbance.As a structural water-conducting channel,fault usually plays a controlling role in hydrogeological structure.During the process of mine water hazard prevention and control,it was discovered that the lithology composition,compaction and cementation degree and water physical properties of karst collapsed column fillings were all non-conducting water,but due to the influence of combined development faults,some exploration drill holes showed concentrated water outflow.Based on this,the scientific hypothesis was proposed that fault cutting leads to water conduction in karst collapsed columns.The study comprehensively used methods like chronology,exploration data analysis,and hydrochemical testing to analyze the chronological relationship between faults and karst collapsed columns,their spatial relationship,outlet point distribution and water chemical properties,and the impact of faults on the water-conductivity of karst collapsed columns,which proved the effect of fault cutting on changing water conductivity of karst collapsed column.The research showed that later fault cutting through karst collapsed columns turned the originally non-conductive karst collapsed columns into water-conductive collapsed columns at the fault plane,creating a longitudinally connected water-conducting channel.A new model of fault cutting karst collapsed column to change the original water conductivity of karst collapsed column was proposed.The research results can provide a theoretical basis for the prediction of the water conductivity of the karst collapsed column.According to whether the karst collapsed column was cut by the fault,it was predicted theoretically,so as to determine the key areas of water conductivity detection and prevention and control,and has broad application prospects under the background of source control of mine water disaster.展开更多
To address the issue of uneven temperature distribution in shale gas oil-based drill cuttings pyrolysis furnaces,a numerical model was developed using Fluent software.The effects of nitrogen flow rate,heating tube spa...To address the issue of uneven temperature distribution in shale gas oil-based drill cuttings pyrolysis furnaces,a numerical model was developed using Fluent software.The effects of nitrogen flow rate,heating tube spacing,and furnace dimensions on the internal temperature field were thoroughly analyzed from a mechanistic perspective.The results indicated that non-uniform radiation from the heating tubes and flow disturbances induced by the nitrogen stream were the primary causes of localized heat concentration.Under no-load conditions,the maximum deviation between simulated and on-site measured temperatures was 1.5%,validating the model’s accuracy.Further-more,this study investigated the trade-offs between temperature uniformity,energy consumption,and construction costs.The findings provide a crucial design basis and a reliable simulation platform for developing and optimizing pyrolysis equipment.展开更多
It is generally believed that cuttings have a significant impact on the forces of tubular string in extended-reach drilling.However,there are few studies attempted to investigate and quantify it.In this paper,a three-...It is generally believed that cuttings have a significant impact on the forces of tubular string in extended-reach drilling.However,there are few studies attempted to investigate and quantify it.In this paper,a three-layer transient model for cuttings transport is established to simulate the characteristics of dynamic cuttings transport over time under various conditions.The simulation results indicate that the change in drilling parameters like ROP(rate of penetration)and flow rate of drilling fluid will lead to the non-uniform distribution of cuttings bed.And the alternation of drilling and circulation will lead to a clear wavy distribution of cuttings bed in the wellbore.Then,the effect of cuttings on tubular string is obtained through a large number of numerical simulations and the nonlinear regression method,and this influence is introduced into the conventional stiff rod model of tubular string.Finally,the transient model for cuttings transport is coupled with the modified tubular mechanic model and applies to a case study of extended-reach drilling.The results show that there is a delay effect for the effect of the changes in drilling parameters on the ground torques because the changes in drilling parameters occur instantaneously,while the changes in cuttings bed distribution are slow due to its low transport velocity.Based on the coupling analysis of transient cuttings transport and tubular mechanical behaviors,the drilling parameters are optimized,including the recommended adjustment period and adjustment range for the ROP,the proper drilling time for the increased flow rate.Furthermore,the circulation and back reaming are optimized.For circulation,the keys are choosing appropriate time interval between the two adjacent circulations and the time for each circulation.To avoid pipe stuck,at least 20 min of circulation is required to remove the cuttings bed near the large-sized BHA((Bottom Hole Assembly))before back reaming,and the maximum back reaming velocity should be smaller than the minimum transport velocity of the uniform bed.展开更多
Water-weakening presents a promising strategy for the in-situ improvement of rock cuttability.This study unveils the influences of water saturation on the mechanical response and fragmentation characteristics of rock ...Water-weakening presents a promising strategy for the in-situ improvement of rock cuttability.This study unveils the influences of water saturation on the mechanical response and fragmentation characteristics of rock samples.A series of rock-cutting tests using conical pick indentation was conducted on three types of sandstone samples under both dry and water-saturated conditions.The relationships between cutting force and indentation depth,as well as typical cuttability indices are determined and compared for dry and water-saturated samples.The experimental results reveal that the presence of water facilitates shearing failure in rock samples,as well as alleviates the fluctuations in the cutting force-indentation depth curve Furthermore,the peak cutting force(F_(p)),cutting work(W_(p)),and specific energy(SE)undergo apparent decrease after water saturation,whereas the trend in the indentation depth at rock failure(D_(f))varies across different rock types.Additionally,the water-induced percentage reductions in F_(p)and SE correlate positively with the quartz and swelling clay content within the rocks,suggesting that the cuttability improvement due to water saturation is attributed to the combined effects of stress corrosion and frictional reduction.These findings carry significant implications for improving rock cuttability in mechanized excavation of hard rock formations.展开更多
Vibration cutting has emerged as a promising method for creating surface functional microstructures.However,achieving precise tool setting is a time-consuming process that significantly impacts process efficiency.This...Vibration cutting has emerged as a promising method for creating surface functional microstructures.However,achieving precise tool setting is a time-consuming process that significantly impacts process efficiency.This study proposes an intelligent approach for tool setting in vibration cutting using machine vision and hearing,divided into two steps.In the first step,machine vision is employed to achieve rough precision in tool setting within tens of micrometers.Subsequently,in the second step,machine hearing utilizes sound pickup to capture vibration audio signals,enabling fine tool adjustment within 1μm precision.The relationship between the spectral intensity of vibration audio and cutting depth is analyzed to establish criteria for tool–workpiece contact.Finally,the efficacy of this approach is validated on an ultra-precision platform,demonstrating that the automated tool-setting process takes no more than 74 s.The total cost of the vision and hearing sensors is less than$1500.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.92160301,92060203,52175415 and 52205475)the Science Center for Gas Turbine Project(No.P2023-B-IV-003-001)+1 种基金the Natural Science Foundation of Jiangsu Province(No.BK20210295)the Huaqiao University Engineering Research Center of Brittle Materials Machining(MOE,2023IME-001)。
文摘The remarkable ability of titanium alloys to preserve their superior physical and chemical characteristics when subjected to extreme conditions significantly enhances their importance in the aerospace,military,and medical sectors.However,conventional machining of titanium alloys leads to elevated tool wear,development of surface defects,and reduced machining efficiency due to their low heat conductivity,and chemical affinity.These issues can be somewhat counteracted by integrating ultrasonic vibration in the conventional machining of titanium alloys and also enhance sustainability.This review article offers a holistic evaluation of the influence of ultrasonic vibration-assisted milling and turning on cutting forces,temperature,tool wear,and surface integrity,encompassing surface morphology,surface roughness,surface residual stress,surface hardness,and surface tribological properties during titanium alloys machining.Furthermore,it investigates the sustainability aspect that has not been previously examined.Studies on the performance of ultrasonic-assisted cutting revealed several advantages,including decreased cutting forces and cutting temperature,improved tool life,and a better-machined surface during machining.Consequently,the sustainability factor is improved due to minimized energy consumption and residual waste.In conclusion,the key challenges and future prospects in the ultrasonic-assisted cutting of titanium alloys are also discussed.This review article provides beneficial knowledge for manufactur-ers and researchers regarding ultrasonic vibration-assisted cutting of titanium alloy and will play an important role in achieving sustainability in the industry.
文摘【目的】基于猪极端饲料报酬表型,利用靶向切割标签技术(cleavage under targets and tagmentation,CUT&Tag)构建H3K27ac差异图谱,鉴定关联的启动子、增强子和关联候选基因,为猪饲料报酬解析提供基础数据。【方法】从209头杜洛克猪中筛选饲料报酬表型差异最大的4头个体分别组成低剩余采食量组(L组,n=2)和高剩余采食量组(H组,n=2)。利用CUT&Tag技术,以H3K27ac作为活性启动子和增强子的表观遗传标记对4头个体的肝脏组织进行全基因组扫描,鉴定关联启动子、增强子和候选基因,并进一步采用real-time quantitative PCR(RT-qPCR)对重要基因进行验证。【结果】共鉴定出47271个H3K27ac峰,包括15739个潜在启动子和31532个推定增强子,大部分的H3K27ac峰位于近端启动子区域。根据H3K27ac全基因的分布情况和作用特点,发现3087个差异峰(对应2188个基因),其中867个H3K27ac峰(对应664个基因)富集在H组,2220个H3K27ac峰(对应1575个基因)富集在L组。GO和KEGG结果发现H3K27ac增强子可能是通过影响胆汁酸代谢、淋巴细胞代谢和NF-κB通路来调节饲料报酬。RT-qPCR结果显示,与H组相比,DIAPH3、DPYD、FTO、TCF7L2、ABCC2、ABCC11、RXRA和ABCG8在L组中显著上调(P<0.05),而PAX5、GRHPR、NFATC1、CARD11、BLNK和LYN在L组中显著下调(P<0.05)。【结论】本研究成功生成了具有极端RFI差异的杜洛克猪肝脏组织中的H3K27ac差异图谱以及相关数据。基于该图谱鉴定和验证了关联候选基因,为进一步解析启动子和增强子调控饲料报酬的分子机制提供了基础数据。
文摘China has a history of more than five thousand years,and its culture is broad and rich.Among many traditional arts,paper-cutting is a special handicraft full of stories and myths.Paper-cutting is a unique art.People use scissors to cut paper into many beautiful shapes,such as flowers,animals,or people.This art only needs simple tools,but it is not as easy as it looks.When we watch the masters cut paper,they can create wonderful patterns in just a few minutes.However,for beginners,a lot of practice and patience are necessary.
基金supported by the National Natural Science Foundation of China(Nos.52425505 and U22A20207)the National Key R&D Program of China(No.2022YFB3403302)the Zhejiang Provincial Key R&D Program of China(No.2023C01056).
文摘With the widespread adoption of ultra-precision machining(UPM)in manufacturing,accurately monitoring the temperature within micro-scale cutting zones has become crucial for ensuring machining quality and tool longevity.This review comprehensively evaluates modern in-process cutting temperature measurement methods,comparing conventional approaches and emerging technologies.Thermal conduction-based and radiation-based measurement paradigms are analyzed in terms of their merits,limitations,and domain-specific applicability,particularly with regard to the unique challenges involving micro-scale cutting zones in UPM.Special emphasis is placed on micro-scale sensor-integrated tools and self-sensing tools that enable real-time thermal monitoring at cutting edges.Furthermore,we explore thermal monitoring and management techniques for atomic and close-to-atomic scale manufacturing(ACSM),as well as the transformative potential of emerging technologies like artificial intelligence(AI),internet of things(IoT),and data fusion for machining temperature measurement.This review may serve as a reference for UPM cutting temperature measurement research,helping foster the development of optimized process control technologies.
文摘A centrifugal pump with a specific speed ns=67 is considered in this study to investigate the impact of blade cutting(at the outlet edge)on the fluid-induced noise,while keeping all the other geometric parameters unchanged.The required unsteady numerical calculations are conducted by applying the RNG k-εturbulence model with the volute dipole being used as the sound source.The results indicate that the internal pressure energy of the centrifugal pump essentially depends on the blade passing frequency and its low-frequency harmonic frequency.Moreover,the pressure pulsation distribution directly affects the noise caused by the centrifugal pump.The sound pressure inside and outside the centrifugal pump and the sound power at the blade passing frequency gradually decrease increasing cutting distance of the impeller blades.When the cutting percentage is 1.21%,that is,the clearance ratio between impeller blade and tongue is 8.57%,the comprehensive performance of the centrifugal pump is the best.
文摘Drill cuttings,though rarely used,are crucial subsurface samples to understand petrographic properties affecting reservoir quality.Unlike core material,cuttings are continuously available along the wellbore and can be used during drilling to monitor progress.Therefore,cuttings may allow a semi-quantitative,statistical calibration of rock properties from the subsurface,but they are often underutilized.Although fracture and vein orientations cannot be reconstructed from drill cuttings,the presence of veins and their internal textures(open,partially sealed or sealed) in specific formation sections and depths can be identified and analyzed using e.g.,transmitted light microscopy and cathodoluminescence to supplement characterization at the well site and subsequently assess production behavior.Borehole gamma ray logs in combination with handheld portable X-ray fluorescence(pXRF) analyses on cleaned and dried drill cuttings can be used to further improve the depth accuracy of the cutting samples and to geochemically fingerprint the samples,based on the Si/Al ratio,as a proxy for sandstone-rich and mudrock-rich sections of the well.In this study,eighty-three sandstone cutting samples from two wells,covering~400 m of stratigraphy targeting the Paleocene-Eocene Greifenstein Fm.equivalent(Glauconite Sandstone,GLS) in the Vienna Basin(Austria),were studied.They also cover parts of three different reservoir sections(1.to 3.GLS).The Flysch play in the Vienna Basin hosts several sand stone-mud rock interbeds and is composed of several nappes,forming complex reservoir compartments.The glauconite contents vary between different sections of the GLS,where the highest is observed in the 3.GLS.The sandstones are predominantly cemented by ferroan calcite,resulting in low optical porosity(<5 %)in both wells,with only individually elevated porosity,related to partially dissolved K-feldspar grains.A paragenetic sequence solely based on cuttings further highlights that reservoir quality in the studied section is independent of sandstone compaction,but is related to lower optical porosity in finer-grained sa ndstones and higher carbonate vein cement conte nts.Furthermo re,productive intervals are related to lower Fe+Mg contents.The understanding of reservoir properties,diagenesis,and their influence on fluid flow is crucial for successful exploration and reduction of uncertainty in reservoir production and development.The diagenetic variations from cuttings and the geochemical fingerprint by pXRF are linked to reservoir quality and production performance of individual well perforations.This approach can provide additional information on reservoir quality where core material is unavailable.
基金supported by the National Natural Science Foundation of China(No.52375443)the Innovative Research Group Project of the National Natural Science Foundation of China(No.51921003)。
文摘To meet the demand for the machining of blisks with narrow cascade channels and twisted blade profiles,especially integral shrouded blisks with shrouds,this paper innovatively proposes a method for dynamic deformation electrochemical cutting of flexible electrodes with arrayed group slit structure.By applying torque to both ends of the flexible electrode,the proposed method produces bending deformation and realizes the processing of a twisted profile.The flexible electrode is an important carrier of this method,and its properties such as elasticity,rigidity,and flow field uniformity have a crucial impact on smooth processing.Therefore,this paper proposes a design theory of flexible electrodes with an arrayed group slit structure and designs flexible electrodes with variable cross-sections.Compared with traditional uniform section tube electrode,the designed flexible electrode was subjected to the corresponding mechanical simulation,flow field simulation,and fluid–structure interaction simulation to investigate the elasticity,rigidity,and flow field uniformity of the flexible electrode.In addition,a deformation device of flexible electrodes was constructed and the corresponding experiments were carried out.Simulations and experiments demonstrate that flexible electrodes with arrayed group slit structures have good comprehensive performance.Finally,typical components were successfully machined to verify the feasibility of the proposed method and the rationality of the designed flexible electrode.It is shown that the proposed method has great potential for the machining of distorted profiles and provides a new idea for the machining of complex profiles.
基金Supported by Jiangsu Provincial Natural Science Foundation(Grant No.BK20231497)Jiangsu Provincial Post Graduate Research&Practice Innovation Program(Grant No.KYCX25_2982)+2 种基金China University of Mining and Technology Graduate Innovation Program(Grant No.2025WLKXJ094)National Natural Science Foundation of China(Grant No.51975573),National Key R&D Program of China(Grant No.2022YFC2905600)Priority Academic Program Development of Jiangsu Higher Education Institute of China.
文摘During the excavation process of deep hard rock tunnels,precutting rock with an abrasive water jet can weaken their strength and improve the efficiency of mining machinery.However,owing to the complex geological environment,abrasive jets cannot fully utilize their rock-cutting performance.To fully exploit the advantages of high-pressure abrasive water jets,five orthogonal experiments were designed for rocks with significant differences in strength.Experimental research has been conducted on the performance of rotating abrasive waterjet-cutting rocks.Moreover,a neural network prediction model for predicting rock-cutting characteristics is established by comprehensively considering rock mechanics parameters and abrasive water jet parameters.The results show that the cutting depth of rocks with different strengths increases nonlinearly with increasing work pressure of the abrasive water jet.The cutting depth decreases exponentially with increasing cutting velocity.The cutting depth first increases and then decreases with increasing target distance,and the best target distance is between 4 mm and 6 mm.The effect of the target distance on the cutting width of rock is the most significant,but the cutting width of high-strength rock is not sensitive to changes in the working parameters of the abrasive water jet.The average relative errors of BP(backpropagation)neural networks optimized by global optimization algorithms in predicting rock cutting depth and width are 13.3%and 5.4%,respectively.This research combines the working characteristics of mining machinery to study the performance of abrasive waterjet rotary cutting of rocks and constructs a predictive model for the performance of abrasive waterjet cutting of rocks that includes rock strength factors.This provides a new solution for quickly adjusting the working parameters of abrasive water jets according to mining conditions.
基金financially supported by the Natural Science Foundation of Guangdong Province(Grant Nos.2023A1515030023,2022B0202110003,2021TQ06N115,2020B121201008)the Special Fund for Scientific Innovation Strategy-Construction of High Level Academy of Agriculture Science(R2023PY-JG025)。
文摘The water content of cut flowers is a significant factor in their post-harvest quality.In this study,we examine the efficacy of silver nanoparticles(NS)on the longevity of cut gladiolus,with a focus on water state and distribution.We used Low-field nuclear magnetic resonance(LF-NMR)technology to identify three water fractions with different transverse relaxation times(T2)values:bound water T21(<10 ms),intermediate immobilized water T22(10-100 ms),and the slowest component free water T23(>10 ms).During the opening process,T23increased at stages 2 and 3 and then decreased,T22 decreased slowly,and T21 remained unchanged.Free water values were consistently higher than bound water and immobilized water and reached their maximum from stage 2 until stage 4,when the petals were extended and began to wilt.The vascular bundles responsible for transporting water had higher water content,as detected by proton density-weighted magnetic resonance imaging(MRI).Bound water and free water with NS pretreatments in bracts were initially lower but then two days later the signal amplitude of each water state exceeded those of the control,indicating that the treatment enhanced the water-holding capacity over time.Furthermore,NS pretreatments reduced the free water mobility of the cut flowers and inhibited stem decay.Additionally,we found that NS can enter the stem and are primarily transported upward along the xylem with water using scanning electron microscopy(SEM)and energy-dispersive X-ray spectroscopy(EDS)technology.Overall,our findings indicate that NS pretreatment reduces free water in gladiolus cut flowers,enhancing their water retention and prolonging their vase life.
基金supported by the National Natural Science Foundation of China(Nos.52174099 and 52474168)the Science and Technology Innovation Program of Hunan Province,China(No.2023RC3050)+1 种基金the Natural Science Foundation of Hunan,China(No.2024JJ4064)the Open Fund of the State Key Laboratory of Safety Technology of Metal Mines(No.kfkt2023-01).
文摘Real-time identification of rock strength and cuttability based on monitoring while cutting during excavation is essential for key procedures such as the precise adjustment of excavation parameters and the in-situ modification of hard rocks.This study proposes an in-telligent approach for predicting rock strength and cuttability.A database comprising 132 data sets is established,containing cutting para-meters(such as cutting depth and pick angle),cutting responses(such as specific energy and instantaneous cutting rate),and rock mech-anical parameters collected from conical pick-cutting experiments.These parameters serve as input features for predicting the uniaxial compressive strength and tensile strength of rocks using regression fitting and machine learning methodologies.In addition,rock cuttabil-ity is classified using a combination of the analytic hierarchy process and fuzzy comprehensive evaluation method,and subsequently iden-tified through machine learning approaches.Various models are compared to determine the optimal predictive and classification models.The results indicate that the optimal model for uniaxial compressive strength and tensile strength prediction is the genetic algorithm-optimized backpropagation neural network model,and the optimal model for rock cuttability classification is the radial basis neural network model.
基金supported by the National Natural Science Foundation of China(Grant Nos.12102392 and 12272341)the Zhejiang Provincial Natural Science Foundation of China(Grant No.LQ21A020008).
文摘Kirigami,through introducing cuts into a thin sheet,can greatly improve the stretchability of structures and also generate complex patterns,showing potentials in various applications.Interestingly,even with the same cutting pattern,the mechanical response of kirigami metamaterials can exhibit significant differences depending on the cutting angles in respect to the loading direction.In this work,we investigate the structural deformation of kirigami metamaterials with square domains and varied cutting angles of 0°and 45°.We further introduce a second level of cutting on the basis of the first cutting pattern.By combining experiments and finite element simulations,it is found that,compared to the commonly used 0°cuts,the two-level kirigami metamaterials with 45°cuts exhibit a unique alternating arrangement phenomenon of expanded/unexpanded states in the loading process,which also results in distinct stress–strain response.Through tuning the cutting patterns of metamaterials with 45°cuts,precise control of the rotation of the kirigami unit is realized,leading to kirigami metamaterials with encryption properties.The current work demonstrates the programmability of structural deformation in hierarchical kirigami metamaterials through controlling the local cutting modes.
基金supported by the Postdoctoral Fellowship Program of CPSF(No.GZC20233005)the Fundamental Research Funds for the Central Universities(No.2024QN11025)+1 种基金the General Program of National Natural Science Foundation of China(No.52274243)the Hebei Province Natural Science Foundation Ecological Wisdom Mine Joint Fund Project(Nos.D2020402013 and D2022402040)。
文摘The water conductivity of karst collapsed column is affected by multiple factors such as the characteristics of its own column filling,structure and mining disturbance.As a structural water-conducting channel,fault usually plays a controlling role in hydrogeological structure.During the process of mine water hazard prevention and control,it was discovered that the lithology composition,compaction and cementation degree and water physical properties of karst collapsed column fillings were all non-conducting water,but due to the influence of combined development faults,some exploration drill holes showed concentrated water outflow.Based on this,the scientific hypothesis was proposed that fault cutting leads to water conduction in karst collapsed columns.The study comprehensively used methods like chronology,exploration data analysis,and hydrochemical testing to analyze the chronological relationship between faults and karst collapsed columns,their spatial relationship,outlet point distribution and water chemical properties,and the impact of faults on the water-conductivity of karst collapsed columns,which proved the effect of fault cutting on changing water conductivity of karst collapsed column.The research showed that later fault cutting through karst collapsed columns turned the originally non-conductive karst collapsed columns into water-conductive collapsed columns at the fault plane,creating a longitudinally connected water-conducting channel.A new model of fault cutting karst collapsed column to change the original water conductivity of karst collapsed column was proposed.The research results can provide a theoretical basis for the prediction of the water conductivity of the karst collapsed column.According to whether the karst collapsed column was cut by the fault,it was predicted theoretically,so as to determine the key areas of water conductivity detection and prevention and control,and has broad application prospects under the background of source control of mine water disaster.
基金funded by the key research on industrialization technologies of low-cost highenergy-density cathode materials(project number:2023GY008)the Sichuan Provincial Science and Technology Program(project number:2024NSFSC1406).
文摘To address the issue of uneven temperature distribution in shale gas oil-based drill cuttings pyrolysis furnaces,a numerical model was developed using Fluent software.The effects of nitrogen flow rate,heating tube spacing,and furnace dimensions on the internal temperature field were thoroughly analyzed from a mechanistic perspective.The results indicated that non-uniform radiation from the heating tubes and flow disturbances induced by the nitrogen stream were the primary causes of localized heat concentration.Under no-load conditions,the maximum deviation between simulated and on-site measured temperatures was 1.5%,validating the model’s accuracy.Further-more,this study investigated the trade-offs between temperature uniformity,energy consumption,and construction costs.The findings provide a crucial design basis and a reliable simulation platform for developing and optimizing pyrolysis equipment.
基金support from the Natural Science Foundation of China(Grant Nos.52222401,52234002,52394255)National Key Research and Development Program of China(Grant No.2023YFC2810901)Science Foundation of China University of Petroleum,Beijing(Grant No.ZXZX20230083).
文摘It is generally believed that cuttings have a significant impact on the forces of tubular string in extended-reach drilling.However,there are few studies attempted to investigate and quantify it.In this paper,a three-layer transient model for cuttings transport is established to simulate the characteristics of dynamic cuttings transport over time under various conditions.The simulation results indicate that the change in drilling parameters like ROP(rate of penetration)and flow rate of drilling fluid will lead to the non-uniform distribution of cuttings bed.And the alternation of drilling and circulation will lead to a clear wavy distribution of cuttings bed in the wellbore.Then,the effect of cuttings on tubular string is obtained through a large number of numerical simulations and the nonlinear regression method,and this influence is introduced into the conventional stiff rod model of tubular string.Finally,the transient model for cuttings transport is coupled with the modified tubular mechanic model and applies to a case study of extended-reach drilling.The results show that there is a delay effect for the effect of the changes in drilling parameters on the ground torques because the changes in drilling parameters occur instantaneously,while the changes in cuttings bed distribution are slow due to its low transport velocity.Based on the coupling analysis of transient cuttings transport and tubular mechanical behaviors,the drilling parameters are optimized,including the recommended adjustment period and adjustment range for the ROP,the proper drilling time for the increased flow rate.Furthermore,the circulation and back reaming are optimized.For circulation,the keys are choosing appropriate time interval between the two adjacent circulations and the time for each circulation.To avoid pipe stuck,at least 20 min of circulation is required to remove the cuttings bed near the large-sized BHA((Bottom Hole Assembly))before back reaming,and the maximum back reaming velocity should be smaller than the minimum transport velocity of the uniform bed.
基金supported by financial grants from the National Natural Science Foundation of China(Grant Nos.52334003 and 52104111)the National Key R&D Program of China(Grant No.2022YFC2905600)。
文摘Water-weakening presents a promising strategy for the in-situ improvement of rock cuttability.This study unveils the influences of water saturation on the mechanical response and fragmentation characteristics of rock samples.A series of rock-cutting tests using conical pick indentation was conducted on three types of sandstone samples under both dry and water-saturated conditions.The relationships between cutting force and indentation depth,as well as typical cuttability indices are determined and compared for dry and water-saturated samples.The experimental results reveal that the presence of water facilitates shearing failure in rock samples,as well as alleviates the fluctuations in the cutting force-indentation depth curve Furthermore,the peak cutting force(F_(p)),cutting work(W_(p)),and specific energy(SE)undergo apparent decrease after water saturation,whereas the trend in the indentation depth at rock failure(D_(f))varies across different rock types.Additionally,the water-induced percentage reductions in F_(p)and SE correlate positively with the quartz and swelling clay content within the rocks,suggesting that the cuttability improvement due to water saturation is attributed to the combined effects of stress corrosion and frictional reduction.These findings carry significant implications for improving rock cuttability in mechanized excavation of hard rock formations.
基金the financial support for this research provided by the National Natural Science Foundation of China(Grant Nos.52275470,124115301,and 52105458)the Natural Science Foundation of Beijing(Grant No.3222009).
文摘Vibration cutting has emerged as a promising method for creating surface functional microstructures.However,achieving precise tool setting is a time-consuming process that significantly impacts process efficiency.This study proposes an intelligent approach for tool setting in vibration cutting using machine vision and hearing,divided into two steps.In the first step,machine vision is employed to achieve rough precision in tool setting within tens of micrometers.Subsequently,in the second step,machine hearing utilizes sound pickup to capture vibration audio signals,enabling fine tool adjustment within 1μm precision.The relationship between the spectral intensity of vibration audio and cutting depth is analyzed to establish criteria for tool–workpiece contact.Finally,the efficacy of this approach is validated on an ultra-precision platform,demonstrating that the automated tool-setting process takes no more than 74 s.The total cost of the vision and hearing sensors is less than$1500.
