Fault is a common geological structure that has been revealed in the process of underground coal excavation and mining.The nature of its discontinuous structure controls the deformation,damage,and mechanics of the coa...Fault is a common geological structure that has been revealed in the process of underground coal excavation and mining.The nature of its discontinuous structure controls the deformation,damage,and mechanics of the coal or rock mass.The interaction between this discontinuous structure and mining activities is a key factor that dominates fault reactivation and the coal burst it can induce.This paper first summarizes investigations into the relationships between coal mining layouts and fault occurrences,along with relevant conceptual models for fault reactivation.Subsequently,it proposes mechanisms of fault reactivation and its induced coal burst based on the superposition of static and dynamic stresses,which include two kinds of fault reactivations from:mining-induced quasi-static stress(FRMSS)-dominated and seismic-based dynamic stress(FRSDS)-dominated.These two kinds of fault reactivations are then validated by the results of experimental investigations,numerical modeling,and in situ microseismic monitoring.On this basis,monitoring methods and prevention strategies for fault-induced coal burst are discussed and recommended.The results show that fault-induced coal burst is triggered by the superposition of high static stress in the fault pillar and dynamic stress from fault reactivation.High static stress comes from the interaction of the fault and the roof structure,and dynamic stress can be ascribed to FRMSS and FRSDS.The results in this paper could be of great significance in guiding the monitoring and prevention of fault-induced coal bursts.展开更多
The remaining useful life(RUL) prediction of mechanical products has been widely studied for online system performance reliability, device remanufacturing, and product safety(safety awareness and safety improvement). ...The remaining useful life(RUL) prediction of mechanical products has been widely studied for online system performance reliability, device remanufacturing, and product safety(safety awareness and safety improvement). These studies incorporated many di erent models, algorithms, and techniques for modeling and assessment. In this paper, methods of RUL assessment are summarized and expounded upon using two major methods: physics model based and data driven based methods. The advantages and disadvantages of each of these methods are deliberated and compared as well. Due to the intricacy of failure mechanism in system, and di culty in physics degradation observation, RUL assessment based on observations of performance variables turns into a science in evaluating the degradation. A modeling method from control systems, the state space model(SSM), as a first order hidden Markov, is presented. In the context of non-linear and non-Gaussian systems, the SSM methodology is capable of performing remaining life assessment by using Bayesian estimation(sequential Monte Carlo). Being e ective for non-linear and non-Gaussian dynamics, the methodology can perform the assessment recursively online for applications in CBM(condition based maintenance), PHM(prognostics and health management), remanufacturing, and system performance reliability. Finally, the discussion raises concerns regarding online sensing data for SSM modeling and assessment of RUL.展开更多
Diffuse midline glioma(DMG),H3K27-altered,is lethal pediatric-type,high-grade,localized to the midline region of the central nervous system.Effective treatment guidelines are absent,and clinical trials are preferred f...Diffuse midline glioma(DMG),H3K27-altered,is lethal pediatric-type,high-grade,localized to the midline region of the central nervous system.Effective treatment guidelines are absent,and clinical trials are preferred for primary or recur-rent DMG patients.Recently,epigenetic agent-based immunotherapy has exhibited promising therapeutic effects in the clinical setting.However,the underlying mechanisms remain a mystery.The rare DMG tumor samples from biopsy or resection largely impede basic research,by using patient-derived tumor cells which better recapitulate the parental tu-mor’s heterogeneity compared to established cell lines.As an epigenetic reprogramming disease,DMG exhibits a global loss of H3K27 trimethylation(H3K27me3)and a gain of H3K27 acetylation(H3K27ac).Analysis of multiple epige-netic marks is fundamentally necessary.However,traditional techniques cannot allow ultra-low input and high-throughput.Herein we have developed a new method called high-throughput in situ tagged immunoprecipitation sequencing(HiTIP-seq),which uses an integrated superhydrophobic microwell array technology(InSMART).We were able to perform 100 parallel assays from as few as 100 cells per microwell on a single chip.We applied the tech-nology to profile epigenetic alterations of three-dimensional(3D)cell cultures derived from DMG patients.Our HiTIP-seq integrated with RNA sequencing(RNA-seq)analysis revealed that the combination of epigenetic agents(panobino-stat and tazemetostat),reprogrammed histone modifications and drove transcriptome changes.Among them,Wnt inhibitory factor 1(WIF1)has a gain of H3K27ac and a loss of H3K27me3,which leads to the upregulated expression.Altogether,HiTIP-seq is a versatile method for high-throughput analysis of histone modifications,suitable for both DMG research and studying rare 3D models.展开更多
A hierarchical structural surface of TiO2 film with reversibly light-switchable wettability between superhydrophobicity and superhydrophilicity on metal substrate was fabricated through simply dip-coating method from ...A hierarchical structural surface of TiO2 film with reversibly light-switchable wettability between superhydrophobicity and superhydrophilicity on metal substrate was fabricated through simply dip-coating method from TiO2 precursor solution containing TiO2 nanoparticles with the average diameter 25 nm (P25),followed by heat-treatment and modification with fluoroalkylsilane (FAS) molecules.The morphology,phase and crystallographic structure,and chemical composite of the as-prepared TiO2 film were characterized by scanning electron microscopy (SEM),X-ray diffraction (XRD),and X-ray photoelectron spectroscopy (XPS).The wettability of TiO2 film was characterized by a drop shape analyzer.The water contact angle of superhydrophobic TiO2 film was up to 165.6°.Under UV irradiation,the water contact angle decreased and the superhydrophobic TiO2 film became superhydrophilic because of hydroxyl groups absorption on the TiO2 surface.Meanwhile,the surface morphology of TiO2 film,which resulted from the TiO2 nanoparticles added in TiO2 precursor solution,had a significant effect on the wettability conversion of TiO2 film and enhanced the switch from hydrophobicity to hydrophilicity.The wettability could be reversibly switched between superhydrophobicity and superhydrophilicity via alternation of UV exposure and dark storage.展开更多
基金This research was carried out by the following funded projects:National Natural Science Foundation of China(51604270,51874292,and 51804303)Fundamental Research Funds for the Central Universities(2017QNA26)+2 种基金Natural Science Foundation of Jiangsu Province(BK20180643)Independent Research Projects of State Key Laboratory of Coal Resources and Safe Mining,China University of Mining and Technology(SKLCRSM15X04)The first author also acknowledges the China Postdoctoral Council International Postdoctoral Exchange Fellowship Program(20170060).
文摘Fault is a common geological structure that has been revealed in the process of underground coal excavation and mining.The nature of its discontinuous structure controls the deformation,damage,and mechanics of the coal or rock mass.The interaction between this discontinuous structure and mining activities is a key factor that dominates fault reactivation and the coal burst it can induce.This paper first summarizes investigations into the relationships between coal mining layouts and fault occurrences,along with relevant conceptual models for fault reactivation.Subsequently,it proposes mechanisms of fault reactivation and its induced coal burst based on the superposition of static and dynamic stresses,which include two kinds of fault reactivations from:mining-induced quasi-static stress(FRMSS)-dominated and seismic-based dynamic stress(FRSDS)-dominated.These two kinds of fault reactivations are then validated by the results of experimental investigations,numerical modeling,and in situ microseismic monitoring.On this basis,monitoring methods and prevention strategies for fault-induced coal burst are discussed and recommended.The results show that fault-induced coal burst is triggered by the superposition of high static stress in the fault pillar and dynamic stress from fault reactivation.High static stress comes from the interaction of the fault and the roof structure,and dynamic stress can be ascribed to FRMSS and FRSDS.The results in this paper could be of great significance in guiding the monitoring and prevention of fault-induced coal bursts.
基金Supported by Fundamental Research Funds for the Central Universities of China(Grant No.DUT17GF214)
文摘The remaining useful life(RUL) prediction of mechanical products has been widely studied for online system performance reliability, device remanufacturing, and product safety(safety awareness and safety improvement). These studies incorporated many di erent models, algorithms, and techniques for modeling and assessment. In this paper, methods of RUL assessment are summarized and expounded upon using two major methods: physics model based and data driven based methods. The advantages and disadvantages of each of these methods are deliberated and compared as well. Due to the intricacy of failure mechanism in system, and di culty in physics degradation observation, RUL assessment based on observations of performance variables turns into a science in evaluating the degradation. A modeling method from control systems, the state space model(SSM), as a first order hidden Markov, is presented. In the context of non-linear and non-Gaussian systems, the SSM methodology is capable of performing remaining life assessment by using Bayesian estimation(sequential Monte Carlo). Being e ective for non-linear and non-Gaussian dynamics, the methodology can perform the assessment recursively online for applications in CBM(condition based maintenance), PHM(prognostics and health management), remanufacturing, and system performance reliability. Finally, the discussion raises concerns regarding online sensing data for SSM modeling and assessment of RUL.
基金supported by grants from the National Science Foundation of China(No.22127804)the National Natural Science Foundation of China(No.81771931 and 31971325)+1 种基金Institute of Biomedicine,the Tsinghua-Peking Joint Center for Life Sciences,and the Clinical Medicine Development Fund of Tsinghua University(No.10001020510)the National Key Research and Development Program of China(No.2016YFC0900200).
文摘Diffuse midline glioma(DMG),H3K27-altered,is lethal pediatric-type,high-grade,localized to the midline region of the central nervous system.Effective treatment guidelines are absent,and clinical trials are preferred for primary or recur-rent DMG patients.Recently,epigenetic agent-based immunotherapy has exhibited promising therapeutic effects in the clinical setting.However,the underlying mechanisms remain a mystery.The rare DMG tumor samples from biopsy or resection largely impede basic research,by using patient-derived tumor cells which better recapitulate the parental tu-mor’s heterogeneity compared to established cell lines.As an epigenetic reprogramming disease,DMG exhibits a global loss of H3K27 trimethylation(H3K27me3)and a gain of H3K27 acetylation(H3K27ac).Analysis of multiple epige-netic marks is fundamentally necessary.However,traditional techniques cannot allow ultra-low input and high-throughput.Herein we have developed a new method called high-throughput in situ tagged immunoprecipitation sequencing(HiTIP-seq),which uses an integrated superhydrophobic microwell array technology(InSMART).We were able to perform 100 parallel assays from as few as 100 cells per microwell on a single chip.We applied the tech-nology to profile epigenetic alterations of three-dimensional(3D)cell cultures derived from DMG patients.Our HiTIP-seq integrated with RNA sequencing(RNA-seq)analysis revealed that the combination of epigenetic agents(panobino-stat and tazemetostat),reprogrammed histone modifications and drove transcriptome changes.Among them,Wnt inhibitory factor 1(WIF1)has a gain of H3K27ac and a loss of H3K27me3,which leads to the upregulated expression.Altogether,HiTIP-seq is a versatile method for high-throughput analysis of histone modifications,suitable for both DMG research and studying rare 3D models.
基金National Natural Science Foundation of China，State Key Laboratory of New Ceramics and Fine Processing,Tsinghua University，Technology Foundation for Selected Overseas Chinese Scholar of Shaanxi Province of China
文摘A hierarchical structural surface of TiO2 film with reversibly light-switchable wettability between superhydrophobicity and superhydrophilicity on metal substrate was fabricated through simply dip-coating method from TiO2 precursor solution containing TiO2 nanoparticles with the average diameter 25 nm (P25),followed by heat-treatment and modification with fluoroalkylsilane (FAS) molecules.The morphology,phase and crystallographic structure,and chemical composite of the as-prepared TiO2 film were characterized by scanning electron microscopy (SEM),X-ray diffraction (XRD),and X-ray photoelectron spectroscopy (XPS).The wettability of TiO2 film was characterized by a drop shape analyzer.The water contact angle of superhydrophobic TiO2 film was up to 165.6°.Under UV irradiation,the water contact angle decreased and the superhydrophobic TiO2 film became superhydrophilic because of hydroxyl groups absorption on the TiO2 surface.Meanwhile,the surface morphology of TiO2 film,which resulted from the TiO2 nanoparticles added in TiO2 precursor solution,had a significant effect on the wettability conversion of TiO2 film and enhanced the switch from hydrophobicity to hydrophilicity.The wettability could be reversibly switched between superhydrophobicity and superhydrophilicity via alternation of UV exposure and dark storage.
