The circadian clock is a highly conserved timekeeping system in organisms,which maintains physiological homeostasis by precisely regulating periodic fluctuations in gene expression.Substantial clinical and experimenta...The circadian clock is a highly conserved timekeeping system in organisms,which maintains physiological homeostasis by precisely regulating periodic fluctuations in gene expression.Substantial clinical and experimental evidence has established a close association between circadian rhythm disruption and the development of various malignancies.Research has revealed characteristic alterations in the circadian gene expression profiles in tumor tissues,primarily manifested as a dysfunction of core clock components(particularly circadian locomotor output cycles kaput(CLOCK)and brain and muscle ARNT-like 1(BMAL1))and the widespread dysregulation of their downstream target genes.Notably,CLOCK demonstrates non-canonical oncogenic functions,including epigenetic regulation via histone acetyltransferase activity and the circadian-independent modulation of cancer pathways.This review systematically elaborates on the oncogenic mechanisms mediated by CLOCK/BMAL1,encompassing multidimensional effects such as cell cycle control,DNA damage response,metabolic reprogramming,and tumor microenvironment(TME)remodeling.Regarding the therapeutic strategies,we focus on cutting-edge approaches such as chrononutritional interventions,chronopharmacological modulation,and treatment regimen optimization,along with a discussion of future perspectives.The research breakthroughs highlighted in this work not only deepen our understanding of the crucial role of circadian regulation in cancer biology but also provide novel insights for the development of chronotherapeutic oncology,particularly through targeting the non-canonical functions of circadian proteins to develop innovative anti-cancer strategies.展开更多
Recent advances in spatially resolved transcriptomics(SRT)have provided new opportunities for characterizing spatial structures of various tissues.Graph-based geometric deep learning has gained widespread adoption for...Recent advances in spatially resolved transcriptomics(SRT)have provided new opportunities for characterizing spatial structures of various tissues.Graph-based geometric deep learning has gained widespread adoption for spatial domain identification tasks.Currently,most methods define adjacency relation between cells or spots by their spatial distance in SRT data,which overlooks key biological interactions like gene expression similarities,and leads to inaccuracies in spatial domain identification.To tackle this challenge,we propose a novel method,SpaGRA(https://github.com/sunxue-yy/SpaGRA),for automatic multi-relationship construction based on graph augmentation.SpaGRA uses spatial distance as prior knowledge and dynamically adjusts edge weights with multi-head graph attention networks(GATs).This helps SpaGRA to uncover diverse node relationships and enhance message passing in geometric contrastive learning.Additionally,SpaGRA uses these multi-view relationships to construct negative samples,addressing sampling bias posed by random selection.Experimental results show that SpaGRA presents superior domain identification performance on multiple datasets generated from different protocols.Using SpaGRA,we analyze the functional regions in the mouse hypothalamus,identify key genes related to heart development in mouse embryos,and observe cancer-associated fibroblasts enveloping cancer cells in the latest Visium HD data.Overall,SpaGRA can effectively characterize spatial structures across diverse SRT datasets.展开更多
Helicopters are playing an increasingly important part in emergency relief, such as earthquake rescue, firefighting and medical transport. With the development of virtual simulation technology, virtual simulation-base...Helicopters are playing an increasingly important part in emergency relief, such as earthquake rescue, firefighting and medical transport. With the development of virtual simulation technology, virtual simulation-based training is widely used in the training of the helicopter crew especially for the dangerous and costly missions mentioned above. A complete training effectiveness evaluation method is proposed to evaluate the trainees＇ training effect based on virtual simulation in this paper. A key to this method is regarding the complicated process as a discrete event-activity flow system and establishing the evaluation indicator system. Then expert group and Analytical Network Process（ANP） are applied to determine the weight of indicators. When the training data are processed, there is a novel attempt to apply Fuzzy Comprehensive Evaluation（FCE） model to calculate the two categories of indicators. Eventually, an experiment and the analysis were carried out to validate the evaluation method.展开更多
Based on dynamic analysis of rolling bearings, the nonlinear dynamic differential equations of a cylindrical roller bearing with a trilobe-raceway were established and solved by the GSTIFF（gear stiff） integer algori...Based on dynamic analysis of rolling bearings, the nonlinear dynamic differential equations of a cylindrical roller bearing with a trilobe-raceway were established and solved by the GSTIFF（gear stiff） integer algorithm with a variable step. The influences of structural parameters and the tolerance of the trilobe-raceway, working conditions of the bearing, and the outer ring installation method on cage slip characteristics were investigated. The results show that：（i） The cage slip ratio and bearing rating life of a cylindrical roller bearing with a trilobe-raceway would reduce when the low-radius（radius of the outer raceway contour at the lowest point） and D-value（difference value between the high and low points of the outer raceway contour） decrease, and the former（low-radius） contributes more significantly.（ii） The cage slip ratio of a cylindrical roller bearing with a trilobe-raceway rises with the increase of the bearing speed, and decreases with the increase of the radial force; the variation range increases with the increase of the low-radius.（iii） When the installation angle of the outer ring increases in a period, the cage slip ratio remains unchanged while the bearing rating life rises up a little. Therefore, when installing a cylindrical roller bearing with a trilobe-raceway, the location of the maximum radius shall be under that of the radial force to improve the bearing rating life.（iv） With the increase of the roundness of the base circle where the radius of the lowest points of the trilobe-raceway contour locates, the cage slip ratio rises gradually and the bearing rating life decreases.展开更多
In the present paper, a metal–organic framework Cr-BDC was prepared and used as adsorbent for adsorption of o-nitrophenol(ONP) and p-nitrophenol(PNP) from aqueous solutions. Cr-BDC was characterized by scanning elect...In the present paper, a metal–organic framework Cr-BDC was prepared and used as adsorbent for adsorption of o-nitrophenol(ONP) and p-nitrophenol(PNP) from aqueous solutions. Cr-BDC was characterized by scanning electron microscopy, transmission electron microscope, X-ray diffraction and BET methods. The results indicate that Cr-BDC gets a very large specific surface area of 4128 m^2·g^(-1)and pore sizes are concentrated in 1 nm, which is a benefit for using for wastewater treatment. The influences of the adsorption conditions, such as temperature,solution concentration, adsorption time and reusability on adsorption performance were investigated. Cr-BDC exhibited an encouraging uptake capacity of 310.0 mg·g^(-1)for ONP, and adsorption capacity of Cr-BDC for ONP is significantly higher than that for PNP under suitable adsorption conditions. The characterizations of adsorption process were examined with the Lagergren pseudo-first-order, the pseudo-second-order kinetic model, and the intra-particular diffusion model. Kinetics experiments indicated that the pseudo-second-order model displayed the best correlation with adsorption kinetics data. Furthermore, our adsorption equilibrium data could be better described by the Freundlich equation. The results indicate that the as-prepared Cr-BDC is promising for use as an effective and economical adsorbent for ONP removal.展开更多
Objective:DNA methylation alterations are early events in carcinogenesis and immune signalling in lung cancer.This study aimed to develop a model based on short stature homeobox 2 gene (SHOX2)/prostaglandin E receptor...Objective:DNA methylation alterations are early events in carcinogenesis and immune signalling in lung cancer.This study aimed to develop a model based on short stature homeobox 2 gene (SHOX2)/prostaglandin E receptor 4gene (PTGER4) DNA methylation in plasma,appearance subtype of pulmonary nodules (PNs) and low-dose computed tomography (LDCT) images to distinguish early-stage lung cancers.Methods:We developed a multimodal prediction model with a training set of 257 individuals.The performance of the multimodal prediction model was further validated in an independent validation set of 42 subjects.In addition,we explored the association between SHOX2/PTGER4 DNA methylation and driver gene mutations in lung cancer based on data from The Cancer Genome Atlas (TCGA) portal.Results:There were significant differences between the early-stage lung cancers and benign groups in the methylation levels.The area under a receiver operator characteristic curve (AUC) of SHOX2 in patients with solid nodules,mixed ground-glass opacity nodules and pure ground-glass opacity nodules were 0.693,0.497 and 0.864,respectively,while the AUCs of PTGER4 were 0.559,0.739 and 0.619,respectively.With the highest AUC of0.894,the novel multimodal prediction model outperformed the Mayo Clinic model (0.519) and LDCT-based deep learning model (0.842) in the independent validation set.Database analysis demonstrated that patients with SHOX2/PTGER4 DNA hypermethylation were enriched in TP53 mutations.Conclusions:The present multimodal prediction model could more efficiently distinguish early-stage lung cancer from benign PNs.A prognostic index based on DNA methylation and lung cancer driver gene alterations may separate the patients into groups with good or poor prognosis.展开更多
The application of helicopter emergency rescue is becoming increasingly widespread,but the flight crew training in this area is still difficult due to high cost and risk.Nevertheless,with the development of Virtual Re...The application of helicopter emergency rescue is becoming increasingly widespread,but the flight crew training in this area is still difficult due to high cost and risk.Nevertheless,with the development of Virtual Reality(VR)technology,virtual simulation has become a significant role in crew training of helicopter rescue.During the implementation of VR-based training,how to transform complex real tasks into VR scenarios and how to evaluate the performance of crew are of great importance.To address these issues,a novel VR-based R-E-A-D(Report,Evaluate,Agree,Do)evaluation model for training is proposed,which is suitable for complex missions with multiple tasks,multiple scenarios,and multiple people.Then,a mapping method of VR scenarios is put forward,which can transform the real tasks into virtual scenarios to serve the virtual simulation training.Finally,an experiment is carried out to verify the feasibility of the evaluation method and virtual scenario mapping method.展开更多
In order to obtain the optimized aircraft design concept which meets the increasingly complex operation environment at the conceptual design stage,System-of-systems(So S)engineering must be considered.This paper propo...In order to obtain the optimized aircraft design concept which meets the increasingly complex operation environment at the conceptual design stage,System-of-systems(So S)engineering must be considered.This paper proposes a novel optimization method for the design of aircraft Mission Success Space(MSS)based on Gaussian fitting and Genetic Algorithm(GA)in the So S area.First,the concepts in the design and evaluation of MSS are summarized to introduce the Contribution to System-of-Systems(CSS)by using a conventional effectiveness index,Mission Success Rate(MSR).Then,the mathematic modelling of Gaussian fitting technique is noted as the basis of the optimization work.After that,the proposed optimal MSS design is illustrated by the multiobjective optimization process where GA acts as the search tool to find the best solution(via Pareto front).In the case study,a simulation system of penetration mission was built.The simulation results are collected and then processed by two MSS design schemes(contour and neural network)giving the initial variable space to GA optimization.Based on that,the proposed optimization method is implemented under both schemes whose optimal solutions are compared to obtain the final best design in the case study.展开更多
Volatile organic compounds(VOCs) have attracted much attention for decades as they are the precursors of photochemical smog and are harmful to the environment and human health. Vacuum ultraviolet(VUV) photodegradation...Volatile organic compounds(VOCs) have attracted much attention for decades as they are the precursors of photochemical smog and are harmful to the environment and human health. Vacuum ultraviolet(VUV) photodegradation is a simple and effective method to decompose VOCs (ranging from tens to hundreds of ppmV) without additional oxidants or catalysts in the air at atmospheric pressure. In this paper, we review the research progress of VOCs removal via VUV photodegradation. The fundamentals are outlined and the key operation factors for VOCs degradation, such as humidity, oxygen content, VOCs initial concentration, light intensity, and flow rate, are discussed. VUV photodegradation of VOCs mixture is elucidated. The application of VUV photodegradation in combination with ozoneassisted catalytic oxidation(OZCO) and photocatalytic oxidation(PCO) systems, and as the pre-treatment technique for biological purification are illustrated. Based on the summary,we propose the challenges of VUV photodegradation and perspectives for its future development.展开更多
Subcanopy tree species are an important component of temperate secondary forests.However,their biomass equations are rarely reported,which forms a“vertical gap”between canopy tree species and understory shrub specie...Subcanopy tree species are an important component of temperate secondary forests.However,their biomass equations are rarely reported,which forms a“vertical gap”between canopy tree species and understory shrub species.In this study,we destructively sampled six common subcanopy species(Syringa reticulate var.amurensis(Rupr.)Pringle,Padus racemosa(Lam.)Gilib.,Acer ginnala Maxim.,Malus baccata(Linn.)Borkh.,Rhamnus davurica Pall.,and Maackia amurensis Rupr.et Maxim.)to establish biomass equations in a temperate forest of Northeast China.The mixed-species and species-specifi c biomass allometric equations were well fi tted against diameter at breast height(DBH).Adding tree height(H)as the second predictor increased the R^(2)of the models compared with the DBH-only models by–1%to+3%.The R^(2)of DBH-only and DBH-H equations for the total biomass of mixed-species were 0.985 and 0.986,respectively.On average,the biomass allocation proportions for the six species were in the order of stem(45.5%)>branch(30.1%)>belowground(19.5%)>foliage(4.9%),with a mean root:shoot ratio of 0.24.Biomass allocation to each specifi c component diff ered among species,which aff ected the performance of the mixed-species model for particular biomass component.When estimating the biomass of subcanopy species using the equations for canopy species(e.g.,Betula platyphylla Suk.,Ulmus davidiana var.japonica(Rehd.)Nakai,and Acer mono Maxim.),the errors in individual biomass estimation increased with tree size(up to 68.8%at 30 cm DBH),and the errors in stand biomass estimation(up to 19.2%)increased with increasing percentage of basal area shared by subcanopy species.The errors caused by selecting such inappropriate models could be removed by multiplying adjustment factors,which were usually power functions of DBH for biomass components.These results provide methodological support for accurate biomass estimation in temperate China and useful guidelines for biomass estimation for subcanopy species in other regions,which can help to improve estimates of forest biomass and carbon stocks.展开更多
Selective hydrogenation of biomass-derived maleic anhydride(MAH)to succinic anhydride(SA)is valuable but remains a challenge due to the complicated reaction network.We here report that single Pt atoms decorated onto t...Selective hydrogenation of biomass-derived maleic anhydride(MAH)to succinic anhydride(SA)is valuable but remains a challenge due to the complicated reaction network.We here report that single Pt atoms decorated onto the edges of two-dimensional(2D)1Tphase MoS_(2)(Pt1/1T-MOS_(2)SAC)as a proof-of-concept catalyst can efficiently convert biomass-derived MAH to SA with 100%conversion and 100%selectivity under mild conditions.The kinetic data and characterization results suggest that the catalytic performance of the edge-anchored Pt1/1T-MoS_(2)SAC originates from the facile H_(2)dissociation induced by the electron-deficient Pt1atoms and the pocket-like configuration of Pt1active site confines the adsorption configuration of MAH by the steric effect.The strategy of fabricating edge-confined catalysts offers a new direction to design novel SACs for biomass-derived transformations.展开更多
Haematococcus pluvialis is an ideal natural source of strong antioxidant astaxanthin.Sodium acetate(NaAc)was proven an effective organic carbon source for improving algal growth and astaxanthin production;however,the ...Haematococcus pluvialis is an ideal natural source of strong antioxidant astaxanthin.Sodium acetate(NaAc)was proven an effective organic carbon source for improving algal growth and astaxanthin production;however,the underlying mechanism remains obscure.To reveal the mechanism of NaAc at the green vegetative stage of H.pluvialis,the physiochemical characteristics and the global protein expression profiles obtained using a tandem mass tag labeling approach were compared between the control(CK)and two NaAc-addition groups.Results show that after NaAc addition,the biomass,nitrate consumption rate,and activities of three carbohydrate metabolism enzymes of H.pluvialis were significantly increased,and the net photosynthetic rate and chlorophyll content decreased.In addition,astaxanthin,total carbohydrates,and total lipids were accumulated,and some red cells appeared in the NaAc5 group.Moreover,317 differentially expressed proteins(DEPs)with the most altered expression patterns were screened out in the CK vs.NaAc5 comparison in our proteomics study.All the DEPs involved in carbohydrate metabolism and lipid metabolism were significantly increased,while most of the photosynthesis-related proteins were depressed in the two NaAc-treated groups.The proteomics results were verified and supported by parallel reaction monitoring approach and physiochemical data.Our findings demonstrate that NaAc promoted the tricarboxylic acid cycle,glyoxylate cycle,and amino acid and lipid synthesis,and inhibited the photo synthe sis-related activities,which consequently speeded up the growth and astaxanthin accumulation in this alga.展开更多
The inner rotors of distributed propulsion tilt-wing Unmanned Aerial Vehicles(UAVs)are often folded in the cruising state and deployed in vertical take-off and landing to cope with the huge difference in thrust requir...The inner rotors of distributed propulsion tilt-wing Unmanned Aerial Vehicles(UAVs)are often folded in the cruising state and deployed in vertical take-off and landing to cope with the huge difference in thrust requirements.However,the blades of the conventional rotor have poor conformality with the nacelle profile,which will greatly increase the drag of the UAV after folding.This paper proposes an integrated method for the design of rotor and nacelle considering geometric compatibility to reduce the drag of the folded rotor and nacelle,so as to further improve the aerodynamic efficiency in cruise while ensuring the rotor efficiency in the vertical flight mode.A geometric mapping model based on nacelle design parameters and rotor design parameters is established,and a parametric model and aerodynamic optimization model of the outer arc airfoil family are developed.In addition,a rotor performance analysis model and a neural network response surface model for nacelle drag prediction that meet the requirements of confidence level are established.Based on the oblique inflow blade element momentum theory method,numerical simulation method,and genetic algorithm,an integrated optimization framework of the design of the conformal rotor and nacelle is built.Then,a geometrically compatible integrated optimization for the rotor and nacelle is carried out with the objective of maximizing energy efficiency in the full mission profile.Finally,a conformal rotor and nacelle design solution is obtained,which satisfies geometric compatibility and thrust constraints while providing high thrust efficiency and low cruising drag.A comparison of the results of the integrated design and the conventional rotor optimization design shows that the drag of the conventional rotor is 3.45 times that of the conformal integrated design in the cruising state,which proves the effectiveness and necessity of the proposed method.展开更多
Gorilla troops optimizer(GTO)is a newly developed meta-heuristic algorithm,which is inspired by the collective lifestyle and social intelligence of gorillas.Similar to othermetaheuristics,the convergence accuracy and ...Gorilla troops optimizer(GTO)is a newly developed meta-heuristic algorithm,which is inspired by the collective lifestyle and social intelligence of gorillas.Similar to othermetaheuristics,the convergence accuracy and stability of GTOwill deterioratewhen the optimization problems to be solved becomemore complex and flexible.To overcome these defects and achieve better performance,this paper proposes an improved gorilla troops optimizer(IGTO).First,Circle chaotic mapping is introduced to initialize the positions of gorillas,which facilitates the population diversity and establishes a good foundation for global search.Then,in order to avoid getting trapped in the local optimum,the lens opposition-based learning mechanism is adopted to expand the search ranges.Besides,a novel local search-based algorithm,namely adaptiveβ-hill climbing,is amalgamated with GTO to increase the final solution precision.Attributed to three improvements,the exploration and exploitation capabilities of the basic GTOare greatly enhanced.The performance of the proposed algorithm is comprehensively evaluated and analyzed on 19 classical benchmark functions.The numerical and statistical results demonstrate that IGTO can provide better solution quality,local optimumavoidance,and robustness compared with the basic GTOand five other wellknown algorithms.Moreover,the applicability of IGTOis further proved through resolving four engineering design problems and training multilayer perceptron.The experimental results suggest that IGTO exhibits remarkable competitive performance and promising prospects in real-world tasks.展开更多
基金supported by the Ministry of Science and Technology of the People’s Republic of China(Nos.2020YFA0803300 and 2021YFA0805600)the National Natural Science Foundation of China(Nos.92157113,82072630,82173114,82072903,82272872,82002811,82188102,and 82030074)+2 种基金the Zhejiang Natural Science Foundation Key Project(Nos.LD22H160002 and LD21H160003)the Zhejiang Natural Science Foundation Discovery Project(No.LQ22H160023)the Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang(No.2019R01001),China.
文摘The circadian clock is a highly conserved timekeeping system in organisms,which maintains physiological homeostasis by precisely regulating periodic fluctuations in gene expression.Substantial clinical and experimental evidence has established a close association between circadian rhythm disruption and the development of various malignancies.Research has revealed characteristic alterations in the circadian gene expression profiles in tumor tissues,primarily manifested as a dysfunction of core clock components(particularly circadian locomotor output cycles kaput(CLOCK)and brain and muscle ARNT-like 1(BMAL1))and the widespread dysregulation of their downstream target genes.Notably,CLOCK demonstrates non-canonical oncogenic functions,including epigenetic regulation via histone acetyltransferase activity and the circadian-independent modulation of cancer pathways.This review systematically elaborates on the oncogenic mechanisms mediated by CLOCK/BMAL1,encompassing multidimensional effects such as cell cycle control,DNA damage response,metabolic reprogramming,and tumor microenvironment(TME)remodeling.Regarding the therapeutic strategies,we focus on cutting-edge approaches such as chrononutritional interventions,chronopharmacological modulation,and treatment regimen optimization,along with a discussion of future perspectives.The research breakthroughs highlighted in this work not only deepen our understanding of the crucial role of circadian regulation in cancer biology but also provide novel insights for the development of chronotherapeutic oncology,particularly through targeting the non-canonical functions of circadian proteins to develop innovative anti-cancer strategies.
基金supported by the National Natural Science Foundation of China(Nos.62303271,U1806202,62103397)the Natural Science Foundation of Shandong Province(ZR2023QF081)Funding for open access charge:the National Natural Science Foundation of China(Nos.62303271,U1806202).
文摘Recent advances in spatially resolved transcriptomics(SRT)have provided new opportunities for characterizing spatial structures of various tissues.Graph-based geometric deep learning has gained widespread adoption for spatial domain identification tasks.Currently,most methods define adjacency relation between cells or spots by their spatial distance in SRT data,which overlooks key biological interactions like gene expression similarities,and leads to inaccuracies in spatial domain identification.To tackle this challenge,we propose a novel method,SpaGRA(https://github.com/sunxue-yy/SpaGRA),for automatic multi-relationship construction based on graph augmentation.SpaGRA uses spatial distance as prior knowledge and dynamically adjusts edge weights with multi-head graph attention networks(GATs).This helps SpaGRA to uncover diverse node relationships and enhance message passing in geometric contrastive learning.Additionally,SpaGRA uses these multi-view relationships to construct negative samples,addressing sampling bias posed by random selection.Experimental results show that SpaGRA presents superior domain identification performance on multiple datasets generated from different protocols.Using SpaGRA,we analyze the functional regions in the mouse hypothalamus,identify key genes related to heart development in mouse embryos,and observe cancer-associated fibroblasts enveloping cancer cells in the latest Visium HD data.Overall,SpaGRA can effectively characterize spatial structures across diverse SRT datasets.
基金supported by National Natural Science Foundation of China (No. 22075063, No. U1932205, No. 22102041)Fundamental Research Funds for the Central Universities (FRFCU5710092520)+4 种基金Chinesisch-Deutschen Zentrum für Wissenschaftsf?rderung (M0281)Natural Science Funds of Heilongjiang Province (No. ZD2019B001)Heilongjiang Touyan Team (HITTY-20190033)the Natural Science Fund for Distinguished Young Scholars of Chongqing ( cstc2021jcyj-jqX0003)“Young Scientist Studio” and Chongqing Research Institute of HIT。
文摘Helicopters are playing an increasingly important part in emergency relief, such as earthquake rescue, firefighting and medical transport. With the development of virtual simulation technology, virtual simulation-based training is widely used in the training of the helicopter crew especially for the dangerous and costly missions mentioned above. A complete training effectiveness evaluation method is proposed to evaluate the trainees＇ training effect based on virtual simulation in this paper. A key to this method is regarding the complicated process as a discrete event-activity flow system and establishing the evaluation indicator system. Then expert group and Analytical Network Process（ANP） are applied to determine the weight of indicators. When the training data are processed, there is a novel attempt to apply Fuzzy Comprehensive Evaluation（FCE） model to calculate the two categories of indicators. Eventually, an experiment and the analysis were carried out to validate the evaluation method.
基金financially co-supported by the National Natural Science Foundation of China (U1404514)Henan Outstanding Person Foundation in China (144200510020)the Collaborative Innovation Center of Major Machine Manufacturing in Liaoning, China
文摘Based on dynamic analysis of rolling bearings, the nonlinear dynamic differential equations of a cylindrical roller bearing with a trilobe-raceway were established and solved by the GSTIFF（gear stiff） integer algorithm with a variable step. The influences of structural parameters and the tolerance of the trilobe-raceway, working conditions of the bearing, and the outer ring installation method on cage slip characteristics were investigated. The results show that：（i） The cage slip ratio and bearing rating life of a cylindrical roller bearing with a trilobe-raceway would reduce when the low-radius（radius of the outer raceway contour at the lowest point） and D-value（difference value between the high and low points of the outer raceway contour） decrease, and the former（low-radius） contributes more significantly.（ii） The cage slip ratio of a cylindrical roller bearing with a trilobe-raceway rises with the increase of the bearing speed, and decreases with the increase of the radial force; the variation range increases with the increase of the low-radius.（iii） When the installation angle of the outer ring increases in a period, the cage slip ratio remains unchanged while the bearing rating life rises up a little. Therefore, when installing a cylindrical roller bearing with a trilobe-raceway, the location of the maximum radius shall be under that of the radial force to improve the bearing rating life.（iv） With the increase of the roundness of the base circle where the radius of the lowest points of the trilobe-raceway contour locates, the cage slip ratio rises gradually and the bearing rating life decreases.
基金Supported by the National Natural Science Foundation of China(No.21676133)the Natural Science Foundation of Fujian Province(2014J01051)
文摘In the present paper, a metal–organic framework Cr-BDC was prepared and used as adsorbent for adsorption of o-nitrophenol(ONP) and p-nitrophenol(PNP) from aqueous solutions. Cr-BDC was characterized by scanning electron microscopy, transmission electron microscope, X-ray diffraction and BET methods. The results indicate that Cr-BDC gets a very large specific surface area of 4128 m^2·g^(-1)and pore sizes are concentrated in 1 nm, which is a benefit for using for wastewater treatment. The influences of the adsorption conditions, such as temperature,solution concentration, adsorption time and reusability on adsorption performance were investigated. Cr-BDC exhibited an encouraging uptake capacity of 310.0 mg·g^(-1)for ONP, and adsorption capacity of Cr-BDC for ONP is significantly higher than that for PNP under suitable adsorption conditions. The characterizations of adsorption process were examined with the Lagergren pseudo-first-order, the pseudo-second-order kinetic model, and the intra-particular diffusion model. Kinetics experiments indicated that the pseudo-second-order model displayed the best correlation with adsorption kinetics data. Furthermore, our adsorption equilibrium data could be better described by the Freundlich equation. The results indicate that the as-prepared Cr-BDC is promising for use as an effective and economical adsorbent for ONP removal.
基金supported by National Natural Science Foundation of China(No.22075063,No.U1932205,No.22102041)Fundamental Research Funds for the Central Universities(FRFCU5710092520)+4 种基金Chinesisch-Deutschen Zentrum für Wissenschaftsf?rderung(M-0281)Natural Science Funds of Heilong jiang Province(No.ZD2019B001)Heilongjiang Touyan Team(HITTY-20190033)"Young Scientist Studio"Chongqing Research Institute of HIT。
基金supported by the National Natural Science Foundation of China(No.81600065 and No.82073805).
文摘Objective:DNA methylation alterations are early events in carcinogenesis and immune signalling in lung cancer.This study aimed to develop a model based on short stature homeobox 2 gene (SHOX2)/prostaglandin E receptor 4gene (PTGER4) DNA methylation in plasma,appearance subtype of pulmonary nodules (PNs) and low-dose computed tomography (LDCT) images to distinguish early-stage lung cancers.Methods:We developed a multimodal prediction model with a training set of 257 individuals.The performance of the multimodal prediction model was further validated in an independent validation set of 42 subjects.In addition,we explored the association between SHOX2/PTGER4 DNA methylation and driver gene mutations in lung cancer based on data from The Cancer Genome Atlas (TCGA) portal.Results:There were significant differences between the early-stage lung cancers and benign groups in the methylation levels.The area under a receiver operator characteristic curve (AUC) of SHOX2 in patients with solid nodules,mixed ground-glass opacity nodules and pure ground-glass opacity nodules were 0.693,0.497 and 0.864,respectively,while the AUCs of PTGER4 were 0.559,0.739 and 0.619,respectively.With the highest AUC of0.894,the novel multimodal prediction model outperformed the Mayo Clinic model (0.519) and LDCT-based deep learning model (0.842) in the independent validation set.Database analysis demonstrated that patients with SHOX2/PTGER4 DNA hypermethylation were enriched in TP53 mutations.Conclusions:The present multimodal prediction model could more efficiently distinguish early-stage lung cancer from benign PNs.A prognostic index based on DNA methylation and lung cancer driver gene alterations may separate the patients into groups with good or poor prognosis.
文摘The application of helicopter emergency rescue is becoming increasingly widespread,but the flight crew training in this area is still difficult due to high cost and risk.Nevertheless,with the development of Virtual Reality(VR)technology,virtual simulation has become a significant role in crew training of helicopter rescue.During the implementation of VR-based training,how to transform complex real tasks into VR scenarios and how to evaluate the performance of crew are of great importance.To address these issues,a novel VR-based R-E-A-D(Report,Evaluate,Agree,Do)evaluation model for training is proposed,which is suitable for complex missions with multiple tasks,multiple scenarios,and multiple people.Then,a mapping method of VR scenarios is put forward,which can transform the real tasks into virtual scenarios to serve the virtual simulation training.Finally,an experiment is carried out to verify the feasibility of the evaluation method and virtual scenario mapping method.
文摘In order to obtain the optimized aircraft design concept which meets the increasingly complex operation environment at the conceptual design stage,System-of-systems(So S)engineering must be considered.This paper proposes a novel optimization method for the design of aircraft Mission Success Space(MSS)based on Gaussian fitting and Genetic Algorithm(GA)in the So S area.First,the concepts in the design and evaluation of MSS are summarized to introduce the Contribution to System-of-Systems(CSS)by using a conventional effectiveness index,Mission Success Rate(MSR).Then,the mathematic modelling of Gaussian fitting technique is noted as the basis of the optimization work.After that,the proposed optimal MSS design is illustrated by the multiobjective optimization process where GA acts as the search tool to find the best solution(via Pareto front).In the case study,a simulation system of penetration mission was built.The simulation results are collected and then processed by two MSS design schemes(contour and neural network)giving the initial variable space to GA optimization.Based on that,the proposed optimization method is implemented under both schemes whose optimal solutions are compared to obtain the final best design in the case study.
文摘Volatile organic compounds(VOCs) have attracted much attention for decades as they are the precursors of photochemical smog and are harmful to the environment and human health. Vacuum ultraviolet(VUV) photodegradation is a simple and effective method to decompose VOCs (ranging from tens to hundreds of ppmV) without additional oxidants or catalysts in the air at atmospheric pressure. In this paper, we review the research progress of VOCs removal via VUV photodegradation. The fundamentals are outlined and the key operation factors for VOCs degradation, such as humidity, oxygen content, VOCs initial concentration, light intensity, and flow rate, are discussed. VUV photodegradation of VOCs mixture is elucidated. The application of VUV photodegradation in combination with ozoneassisted catalytic oxidation(OZCO) and photocatalytic oxidation(PCO) systems, and as the pre-treatment technique for biological purification are illustrated. Based on the summary,we propose the challenges of VUV photodegradation and perspectives for its future development.
基金supported by the National Key Research and Development Program(2021YFD220040105)National Natural Science Foundation of China(32171765).
文摘Subcanopy tree species are an important component of temperate secondary forests.However,their biomass equations are rarely reported,which forms a“vertical gap”between canopy tree species and understory shrub species.In this study,we destructively sampled six common subcanopy species(Syringa reticulate var.amurensis(Rupr.)Pringle,Padus racemosa(Lam.)Gilib.,Acer ginnala Maxim.,Malus baccata(Linn.)Borkh.,Rhamnus davurica Pall.,and Maackia amurensis Rupr.et Maxim.)to establish biomass equations in a temperate forest of Northeast China.The mixed-species and species-specifi c biomass allometric equations were well fi tted against diameter at breast height(DBH).Adding tree height(H)as the second predictor increased the R^(2)of the models compared with the DBH-only models by–1%to+3%.The R^(2)of DBH-only and DBH-H equations for the total biomass of mixed-species were 0.985 and 0.986,respectively.On average,the biomass allocation proportions for the six species were in the order of stem(45.5%)>branch(30.1%)>belowground(19.5%)>foliage(4.9%),with a mean root:shoot ratio of 0.24.Biomass allocation to each specifi c component diff ered among species,which aff ected the performance of the mixed-species model for particular biomass component.When estimating the biomass of subcanopy species using the equations for canopy species(e.g.,Betula platyphylla Suk.,Ulmus davidiana var.japonica(Rehd.)Nakai,and Acer mono Maxim.),the errors in individual biomass estimation increased with tree size(up to 68.8%at 30 cm DBH),and the errors in stand biomass estimation(up to 19.2%)increased with increasing percentage of basal area shared by subcanopy species.The errors caused by selecting such inappropriate models could be removed by multiplying adjustment factors,which were usually power functions of DBH for biomass components.These results provide methodological support for accurate biomass estimation in temperate China and useful guidelines for biomass estimation for subcanopy species in other regions,which can help to improve estimates of forest biomass and carbon stocks.
基金financially supported by the National Natural Science Foundation of China(Nos.21908079,21872145 and U21A20326)Jiangsu Specially-Appointed Professor Fund(No.1046010241211400)+4 种基金Natural Science Foundation of Jiangsu Province(Nos.BK20211239,BK20221541 and BK20201345)the State Key Laboratory of Fine ChemicalsDalian University of Technology(No.KF2005)Dalian Institute of Chemical Physics(No.DICP 1201943)the Central Laboratory,School of Chemical and Material Engineering,Jiangnan University。
文摘Selective hydrogenation of biomass-derived maleic anhydride(MAH)to succinic anhydride(SA)is valuable but remains a challenge due to the complicated reaction network.We here report that single Pt atoms decorated onto the edges of two-dimensional(2D)1Tphase MoS_(2)(Pt1/1T-MOS_(2)SAC)as a proof-of-concept catalyst can efficiently convert biomass-derived MAH to SA with 100%conversion and 100%selectivity under mild conditions.The kinetic data and characterization results suggest that the catalytic performance of the edge-anchored Pt1/1T-MoS_(2)SAC originates from the facile H_(2)dissociation induced by the electron-deficient Pt1atoms and the pocket-like configuration of Pt1active site confines the adsorption configuration of MAH by the steric effect.The strategy of fabricating edge-confined catalysts offers a new direction to design novel SACs for biomass-derived transformations.
基金Supported by the National Natural Science Foundation of China(No31572638)the K.C.Wong Magna Fund in Ningbo University。
文摘Haematococcus pluvialis is an ideal natural source of strong antioxidant astaxanthin.Sodium acetate(NaAc)was proven an effective organic carbon source for improving algal growth and astaxanthin production;however,the underlying mechanism remains obscure.To reveal the mechanism of NaAc at the green vegetative stage of H.pluvialis,the physiochemical characteristics and the global protein expression profiles obtained using a tandem mass tag labeling approach were compared between the control(CK)and two NaAc-addition groups.Results show that after NaAc addition,the biomass,nitrate consumption rate,and activities of three carbohydrate metabolism enzymes of H.pluvialis were significantly increased,and the net photosynthetic rate and chlorophyll content decreased.In addition,astaxanthin,total carbohydrates,and total lipids were accumulated,and some red cells appeared in the NaAc5 group.Moreover,317 differentially expressed proteins(DEPs)with the most altered expression patterns were screened out in the CK vs.NaAc5 comparison in our proteomics study.All the DEPs involved in carbohydrate metabolism and lipid metabolism were significantly increased,while most of the photosynthesis-related proteins were depressed in the two NaAc-treated groups.The proteomics results were verified and supported by parallel reaction monitoring approach and physiochemical data.Our findings demonstrate that NaAc promoted the tricarboxylic acid cycle,glyoxylate cycle,and amino acid and lipid synthesis,and inhibited the photo synthe sis-related activities,which consequently speeded up the growth and astaxanthin accumulation in this alga.
基金the Fundamental Research Funds for the Central Universities(No.56XCA2205402).
文摘The inner rotors of distributed propulsion tilt-wing Unmanned Aerial Vehicles(UAVs)are often folded in the cruising state and deployed in vertical take-off and landing to cope with the huge difference in thrust requirements.However,the blades of the conventional rotor have poor conformality with the nacelle profile,which will greatly increase the drag of the UAV after folding.This paper proposes an integrated method for the design of rotor and nacelle considering geometric compatibility to reduce the drag of the folded rotor and nacelle,so as to further improve the aerodynamic efficiency in cruise while ensuring the rotor efficiency in the vertical flight mode.A geometric mapping model based on nacelle design parameters and rotor design parameters is established,and a parametric model and aerodynamic optimization model of the outer arc airfoil family are developed.In addition,a rotor performance analysis model and a neural network response surface model for nacelle drag prediction that meet the requirements of confidence level are established.Based on the oblique inflow blade element momentum theory method,numerical simulation method,and genetic algorithm,an integrated optimization framework of the design of the conformal rotor and nacelle is built.Then,a geometrically compatible integrated optimization for the rotor and nacelle is carried out with the objective of maximizing energy efficiency in the full mission profile.Finally,a conformal rotor and nacelle design solution is obtained,which satisfies geometric compatibility and thrust constraints while providing high thrust efficiency and low cruising drag.A comparison of the results of the integrated design and the conventional rotor optimization design shows that the drag of the conventional rotor is 3.45 times that of the conformal integrated design in the cruising state,which proves the effectiveness and necessity of the proposed method.
基金This work is financially supported by the Fundamental Research Funds for the Central Universities under Grant 2572014BB06.
文摘Gorilla troops optimizer(GTO)is a newly developed meta-heuristic algorithm,which is inspired by the collective lifestyle and social intelligence of gorillas.Similar to othermetaheuristics,the convergence accuracy and stability of GTOwill deterioratewhen the optimization problems to be solved becomemore complex and flexible.To overcome these defects and achieve better performance,this paper proposes an improved gorilla troops optimizer(IGTO).First,Circle chaotic mapping is introduced to initialize the positions of gorillas,which facilitates the population diversity and establishes a good foundation for global search.Then,in order to avoid getting trapped in the local optimum,the lens opposition-based learning mechanism is adopted to expand the search ranges.Besides,a novel local search-based algorithm,namely adaptiveβ-hill climbing,is amalgamated with GTO to increase the final solution precision.Attributed to three improvements,the exploration and exploitation capabilities of the basic GTOare greatly enhanced.The performance of the proposed algorithm is comprehensively evaluated and analyzed on 19 classical benchmark functions.The numerical and statistical results demonstrate that IGTO can provide better solution quality,local optimumavoidance,and robustness compared with the basic GTOand five other wellknown algorithms.Moreover,the applicability of IGTOis further proved through resolving four engineering design problems and training multilayer perceptron.The experimental results suggest that IGTO exhibits remarkable competitive performance and promising prospects in real-world tasks.
