Formation behaviors of rod-like reactive shaped charge penetrator(RRSCP)and their effects on damage capability are investigated by experiments and numerical simulations.The pulsed X-ray technology and a spaced aluminu...Formation behaviors of rod-like reactive shaped charge penetrator(RRSCP)and their effects on damage capability are investigated by experiments and numerical simulations.The pulsed X-ray technology and a spaced aluminum/steel plate with the thicknesses of 5 mm/100 mm are used.Three types of sphericalsegment aluminum-polytetrafluoroethylene-copper(Al-PTFE-Cu)reactive liners with Cu contents of 0%,46.6%,and 66%are fabricated and tested.The experimental results show that the reactive liners can form excellent rod-shaped penetrators with tail skirts under the shaped charge effect,but the tail skirts disappear over time.Moreover,rupturing damage to the aluminum plate and penetration to the steel plate are caused by the RRSCP impact.From simulation analysis,the RRSCP is formed by a mechanically and chemically coupled response with the reactive liner activated by shock in its outer walls and bottom and then backward overturning,forming a leading reactive penetrator and a following chemical energy cluster.The unique formation structure determines the damage modes of the aluminum plate and the steel plate.Further analysis indicates that the formation behaviors and damage capability of Al-PTFE-Cu RRSCP strongly depend on Cu content.With increasing Cu content,the velocity,activation extent,and reaction extent of Al-PTFE-Cu RRSCP decrease,which contribute to elongation and alleviate the negative effects of chemical reactions on elongation,significantly increasing the length-diameter ratio and thus enhancing the capability of steel plate penetration.However,the lower activation extent and energetic density will weaken the RRSCP's capability of causing rupturing damage to the aluminum plate.展开更多
To investigate the thermal response and initiation behavior of ternary fluoropolymer-matrix PTFE/Al/W reactive materials,a research combining shock loading tests and trans-scale modelling is conducted.On the basis of ...To investigate the thermal response and initiation behavior of ternary fluoropolymer-matrix PTFE/Al/W reactive materials,a research combining shock loading tests and trans-scale modelling is conducted.On the basis of a good agreement of the numerically simulated and tested shock wave propagation,the significant impact of component ratios and particle sizes on the evolution of mesoscopic temperature,hot-spots and initiation is well characterized and analyzed.Results demonstrate that as the content of W increases,the range of mesoscopic high-temperature area increases and tends to distribute more uniform,while material with smaller W particles causes more intense particle deformation and larger temperature rise.The time to reach the critical temperature shows positive correlation to the content of W,while the critical temperature of hot-spots shows negative correlation to the particle size of W.For PTFE/Al/W of high density,with the increase of W particle size,the reaction rate decrease,however the time to reach the peak reaction rate shortens.展开更多
Combining the methods of theoretical,numerical and experimental,this research focuses on the jet formation behavior and optimization of trunconical hypercumulation shaped charge structure.With the three-stage division...Combining the methods of theoretical,numerical and experimental,this research focuses on the jet formation behavior and optimization of trunconical hypercumulation shaped charge structure.With the three-stage division,formation theory of trunconical hypercumulation shaped charge jet is established based on micro element method.By dimensional analysis,main control parameters are identified and their effect on jet formation are analyzed.Through numerical modelling and orthogonal optimization method,influence of the factors and their levels over the indicators of jet tip velocity and jet length as well as order of the significance of each factor and level are obtained.Penetration experiments of trunconical hypercumulation shaped charge based on the orthogonal optimization reveals its advantage over traditional conical shaped charge structure,and finally determines the optimal influence factor level combination.The research and results would provide useful guide for the design and application of trunconical hypercumulation shaped charge structure.展开更多
Background Alginate oligosaccharide(AOS)holds great potential as a novel feed supplement in farm animals.However,the effects of AOS on chicken health and the underlying mechanisms are not fully understood.This study a...Background Alginate oligosaccharide(AOS)holds great potential as a novel feed supplement in farm animals.However,the effects of AOS on chicken health and the underlying mechanisms are not fully understood.This study aimed to optimize the enzymatic preparation of AOS by using bacterial alginate lyases expressed in yeast,investigate the effects of the prepared AOS on the growth performance and gut health of broiler chickens,and reveal the underlying mechanisms.Results Five alginate lyases from bacteria were cloned into Pichia pastoris GS115 and the alginate lyase PDE9 was expressed at relatively high yield,activity and stability in P.pastoris.Animal trials were carried out using 3201-day-old male Arbor Acres broilers(four groups;8 replicates/group×10 chicks/replicate)receiving either a basal diet or the same diet supplemented with 100,200 and 400 mg/kg PDE9-prepared AOS for 42 d.The results showed that dietary supplementation of 200 mg/kg AOS displayed the highest activity in promoting the birds’ADG and ADFI(P<0.05).AOS ameliorated the intestinal morphology,absorption function and barrier function,as indicated by the enhanced(P<0.05)intestinal villus height,maltase activity,and the expression of PEPT,SGLT1,ZNT1,and occludin.AOS also increased serum insulin-like growth factor-1,ghrelin(P<0.05),and growth hormone(P<0.1).Moreover,the concentrations of acetate,isobutyrate,isovalerate,valerate,and total SCFAs in cecum of birds fed AOS were significantly higher than the control birds(P<0.05).Metagenomic analysis indicated that AOS modulated the chicken gut microbiota structure,function,and microbial interactions and promoted the growth of SCFAs-producing bacteria,for example,Dorea sp.002160985;SCFAs,especially acetate,were found positively correlated with the chicken growth performance and growth-related hormone signals(P<0.05).We further verified that AOS can be utilized by Dorea sp.to grow and to produce acetate in vitro.Conclusions We demonstrated that the enzymatically produced AOS effectively promoted broiler chicken growth performance by modulating the chicken gut microbiota structure and function.For the first time,we established the connections among AOS,chicken gut microbiota/SCFAs,growth hormone signals and chicken growth performance.展开更多
Copper-indium-gallium-diselenide(CIGS)is a fast-evolving commercial solar cell.The firm demand for global carbon reduction and the rise of potential environmental threats necessitate spent CIGS solar cell recycling.In...Copper-indium-gallium-diselenide(CIGS)is a fast-evolving commercial solar cell.The firm demand for global carbon reduction and the rise of potential environmental threats necessitate spent CIGS solar cell recycling.In this paper,the sources and characteristics of valuable metals in spent CIGS solar cells were reviewed.The potential environmental impacts of CIGS,including service life,critical material,and material toxicity,were outlined.The main recovery methods of valuable metals in the various types of spent CIGS,including hydrometallurgy,pyrometallurgy,and comprehensive treatment processes,were compared and discussed.The mechanism of different recovery processes was summarized.The challenges faced by different recycling processes of spent CIGS were also covered in this review.Finally,the economic viability of the recycling process was assessed.The purpose of this review is to provide reasonable suggestions for the sustainable development of CIGS and the harmless disposal of spent CIGS.展开更多
AIM:To examine the change of iris volume measured by CASIA2 anterior segment optical coherence tomography(ASOCT)in glaucoma patients with or without type 2 diabetes mellitus(T2DM)and explore if there is a correlation ...AIM:To examine the change of iris volume measured by CASIA2 anterior segment optical coherence tomography(ASOCT)in glaucoma patients with or without type 2 diabetes mellitus(T2DM)and explore if there is a correlation between hemoglobin A1c(HbA1c)level and iris volume.METHODS:In a cross-sectional study,72 patients(115 eyes)were divided into two groups:primary open angle glaucoma(POAG)group(55 eyes)and primary angle-closure glaucoma(PACG)group(60 eyes).Patients in each group were separately classified into patients with or without T2DM.Iris volume and glycosylated HbA1c level were measured and analyzed.RESULTS:In the PACG group,diabetic patients'iris volume was significantly lower than those of non-diabetics(P=0.02),and there was a significant correlation between iris volume and HbA1c level in the PACG group(r=-0.26,P=0.04).However,diabetic POAG patients'iris volume was noticeably higher than those of non-diabetics(P=0.01),and there was a significant correlation between HbA1c level and iris volume(r=0.32,P=0.02).CONCLUSION:Diabetes mellitus impact iris volume size,as seen by increased iris volume in the POAG group and decreased iris volume in the PACG group.In addition,iris volume is significantly correlated with HbA1c level in glaucoma patients.These findings imply that T2DM may compromise iris ultrastructure in glaucoma patients.展开更多
<strong>Objectives:</strong> This study aims to present the characteristics of the undergraduate dental curriculum system using network modelling and visualisation analysis based on complex network theory,...<strong>Objectives:</strong> This study aims to present the characteristics of the undergraduate dental curriculum system using network modelling and visualisation analysis based on complex network theory, thus providing a theoretical foundation for the course development and curriculum reform. <strong>Methods:</strong> The correlation coefficient was used to quantify the intensity of the correlation between courses, and a visualisation complex network of the dental curriculum was built to explore the curriculum pattern from a dynamic perspective. Further, the statistical measurements of curriculum network were adopted to express the most relevant topological features. Subsequently, the minimum spanning tree and parallel coordinates plot were drawn to explore the curriculum community structure, quantify the key courses, and present different courses in time and space relationships. <strong>Results:</strong> The correlation analysis results show that the courses are closely related to each other. The main courses focus on pathology, pathophysiology, oral anatomy and physiology, closely connecting almost all medicine-related courses. The whole course network has an average degree value of 41.53, and a clustering coefficient of 0.78, indicating an obvious small-world characteristic. From the perspective of curriculum attributes, the number of public and theoretical courses was more than that of skills and practical courses. Moreover, the academic performance of skills and practical courses was lower than that of public and theoretical courses. <strong>Conclusion:</strong> The undergraduate dental courses have a progressive structure from basic professional knowledge to professional skills, which is reasonable for the dental education in China. However, some efforts towards curriculum reform based on this study are needed.展开更多
Seedlings of Taxus chinensis var.mairei were used as experimental materials to study the adaptation of Piriformospora indica to this plant under water stress.The materials were divided into two groups,namely,with or w...Seedlings of Taxus chinensis var.mairei were used as experimental materials to study the adaptation of Piriformospora indica to this plant under water stress.The materials were divided into two groups,namely,with or without inoculation with P.indica.Each group was subjected to four different levels of water stress.Vitality and physiological and biochemical indexes of the roots of T.chinensis var.mairei were regularly measured.Under water stress,T.chinensis var.mairei had significantly decreased root vitality;root vitality was higher in inoculated roots than in uninoculated roots.Under intense water stress,the inoculated roots had a higher soluble sugar content than the uninoculated roots.Under water stress,T.chinensis var.mairei experienced decreased activity of aerobic respiratory metabolic enzymes.The activity of anaerobic respiratory metabolic enzymes and alcohol dehydrogenase initially increased and then decreased,whereas that of lactate dehydrogenase increased.The inoculated roots had a higher activity of respiratory metabolic enzymes than the uninoculated roots.As water stress was further intensified,the roots had significantly decreased activity of aerobic respiratory metabolic enzymes and significantly increased activity of anaerobic respiratory metabolic enzymes.The activity of respiratory metabolic enzymes decreased faster in the uninoculated roots than in the inoculated roots.This study demonstrated that Piriformospora indica plays a positive role in enhancing the antihypoxic ability of T.chinensis var.mairei,thereby alleviating plant damage due to water stress.展开更多
AIM:To investigate the association of axial length(AL),lens thickness(LT),and lens vault(LV)with postoperative anterior chamber angle metrics after laser peripheral iridotomy(LPI).METHODS:Prospective observational stu...AIM:To investigate the association of axial length(AL),lens thickness(LT),and lens vault(LV)with postoperative anterior chamber angle metrics after laser peripheral iridotomy(LPI).METHODS:Prospective observational study of 69 patients(97 eyes)were diagnosed as primary angle-closure suspect(PACS),primary angle closure(PAC)or primary angle-closure glaucoma(PACG).AL,LT,anterior central chamber depth(ACD),angle opening distance(AOD),trabecular iris angle(TIA),and angle recess area(ARA)were measured before and 1 wk after LPI.The association between AL,LT,LV with ACD,AOD,TIA,ARA were analyzed by comparing the differences between preoperative and postoperative measurements for anterior segment biometric parameters.RESULTS:ACD,AOD,TIA,and ARA were significantly increased after LPI(all P<0.05).Greater LT was significantly associated with greater postoperative increases in ACD,AOD,TIA,and ARA(all P<0.05).AL was not significantly associated with changes of anterior segment biometric parameters.Greater LV was significantly associated with greater postoperative increases in ACD,AOD,and TIA(all P<0.05),but was not significantly associated with changes of ARA.CONCLUSION:Greater baseline LT and LV measurements are associated with greater increases in anterior segment biometric parameters after laser peripheral iridotomy.AL are not associated with the change of anterior segment biometric parameters.展开更多
Fast data synchronization in wireless ad hoc networks is a challenging and critical problem.It is fundamental for efficient information fusion,control and decision in distributed systems.Previously,distributed data sy...Fast data synchronization in wireless ad hoc networks is a challenging and critical problem.It is fundamental for efficient information fusion,control and decision in distributed systems.Previously,distributed data synchronization was mainly studied in the latency-tolerant distributed databases,or assuming the general model of wireless ad hoc networks.In this paper,we propose a pair of linear network coding(NC)and all-to-all broadcast based fast data synchronization algorithms for wireless ad hoc networks whose topology is under operator’s control.We consider both data block selection and transmitting node selection for exploiting the benefits of NC.Instead of using the store-and-forward protocol as in the conventional uncoded approach,a compute-and-forward protocol is used in our scheme,which improves the transmission efficiency.The performance of the proposed algorithms is studied under different values of network size,network connection degree,and per-hop packet error rate.Simulation results demonstrate that our algorithms significantly reduce the times slots used for data synchronization compared with the baseline that does not use NC.展开更多
As a special type of mobile ad hoc network(MANET),the flying ad hoc network(FANET)has the potential to enable a variety of emerging applications in both civilian wireless communications(e.g.,5G and 6G)and the defense ...As a special type of mobile ad hoc network(MANET),the flying ad hoc network(FANET)has the potential to enable a variety of emerging applications in both civilian wireless communications(e.g.,5G and 6G)and the defense industry.The routing protocol plays a pivotal role in FANET.However,when designing the routing protocol for FANET,it is conventionally assumed that the aerial nodes move randomly.This is clearly inappropriate for a mission-oriented FANET(MO-FANET),in which the aerial nodes typically move toward a given destination from given departure point(s),possibly along a roughly deterministic flight path while maintaining a well-established formation,in order to carry out certain missions.In this paper,a novel cyber–physical routing protocol exploiting the particular mobility pattern of an MO-FANET is proposed based on cross-disciplinary integration,which makes full use of the missiondetermined trajectory dynamics to construct the time sequence of rejoining and separating,as well as the adjacency matrix for each node,as prior information.Compared with the existing representative routing protocols used in FANETs,our protocol achieves a higher packet-delivery ratio(PDR)at the cost of even lower overhead and lower average end-to-end latency,while maintaining a reasonably moderate and stable network jitter,as demonstrated by extensive ns-3-based simulations assuming realistic configurations in an MO-FANET.展开更多
A new frustrated triangular lattice antiferromagnet Na_(2)BaNi(PO_(4))_(2) was synthesized by high temperature flux method.The two-dimensional triangular lattice is formed by the Ni^(2+)ions with S=1.Its magnetism is ...A new frustrated triangular lattice antiferromagnet Na_(2)BaNi(PO_(4))_(2) was synthesized by high temperature flux method.The two-dimensional triangular lattice is formed by the Ni^(2+)ions with S=1.Its magnetism is highly anisotropic with the Weiss constants θCW=6.615 K(H||c)and43.979 K(H⊥c).However,no magnetic ordering is present down to 0.3 K,reflecting strong geometric spin frustration.Our heat capacity measurements show substantial residual magnetic entropy existing below 0.3 K at zero field,implying the presence of low energy spin excitations.These results indicate that Na_(2)BaNi(PO_(4))_(2) is a potential spin liquid candidate with spin-1.展开更多
Four different ratios of river sand,ceramic pellets,vermiculite and perlite(1:1),and field soil were selected as the substrates in this experiment,and four gradient levels of root waterlogging,half waterlogging,full w...Four different ratios of river sand,ceramic pellets,vermiculite and perlite(1:1),and field soil were selected as the substrates in this experiment,and four gradient levels of root waterlogging,half waterlogging,full waterlogging and normal were set to investigate the effects of different gradients of waterlogging stress on the root morphology of Taxus chinensis var.mairei seedlings under different substrates.In this study,the root anatomical structure of Taxus chinensis var.mairei under different waterlogging stress was observed by the paraffin section method.The roots of T.chinensis var.mairei were diarch,with no pith and resin canals.There was a large number of tannins in the pericycle of the aerial adventitious roots of seedlings adapted to waterlogging.Also,the endodermis has obvious casparian strip thickening,and there were 4-5 layers of large parenchymatous cells in the close to the inner side of the pericycle in the vascular cylinder,which could increase the storage capacity,and transport capacity of the root.Under the treatment of root waterlogging stress,the development of plant roots in the mixed substrate of vermiculite and,perlite was the earliest.Under half waterlogging stress,T.chinensis var.mairei seedlings treated with various substrates all could better adapt to the environment of waterlogging stress.Under the stress of fully waterlogging,the roots of seedlings planted in river sand substrate developed secondary growth.展开更多
Objective:To investigate the effects of chronic unpredictable mild stress(CUMS)on perineuronal nets(PNNs)andγ-aminobutyric acid(GABA)-ergic neurons in the medial prefrontal cortex(mPFC)of adult rats.Methods:28 rats w...Objective:To investigate the effects of chronic unpredictable mild stress(CUMS)on perineuronal nets(PNNs)andγ-aminobutyric acid(GABA)-ergic neurons in the medial prefrontal cortex(mPFC)of adult rats.Methods:28 rats were randomly divided into two groups.The model group adopted CUMS to establish a depression model,and the control group did not give any treatment.The density of PNNs and the percentage of PNNs positive(PNNs^(+))and parvalbumin positive(PV^(+))neurons in total PV^(+)neurons in the mPFC were detected by immunofluorescence.The protein expression of main components of PNNs,Aggrecan and Brevican,and GABA main synthase glutamic acid decarboxylase 67(GAD67)in the mPFC were detected by Western blot.Results:The density of PNNs and the percentage of PNNs^(+)and PV^(+)neurons in total PV^(+)neurons in the mPFC in the model group were decreased compared with the control group(P<0.05);The expression levels of PNNs component proteins Aggrecan and Brevican,and GABA main synthase GAD67 were also decreased in the model group(P<0.01).Conclusion:The levels of PNNs and GABA synthase GAD67 in the mPFC of rats were decreased after chronic unpredictable mild stress.展开更多
Objective:To explore the changes of cannabinoid receptor(CB1)and AMPA receptor subunit GluA1 in the medial prefrontal cortex(mPFC)of depression model rats induced by chronic unpredictable mild stress(CUMS).Methods:30 ...Objective:To explore the changes of cannabinoid receptor(CB1)and AMPA receptor subunit GluA1 in the medial prefrontal cortex(mPFC)of depression model rats induced by chronic unpredictable mild stress(CUMS).Methods:30 rats were randomly divided into three groups.The three-week model group was given a three-week CUMS model,the four-week model group was given a four-week CUMS model,and the control group was given no treatment.The behavior of rats were detected in each group,and the expression of CB1 and GluA1 protein in synaptosomes in mPFC brain region was detected by Western blot.Results:Compared with the control group,the surcose preference decreased,the feeding latency increased in the novel inhibition feeding test,and the immobility time increased in the forced swimming test in the four-week model group.However,after three weeks of CUMS,there was no obvious change in the behavior of rats compared with the control group,suggesting that four-week model of CUMS was successful.CUMS can reduce the expression level of CB1 and GluA1 protein in synaptosomes of mPFC brain area in four-week model group(P<0.05),but there was no significant difference between three-week model group and control group.Conclusion:Four-week CUMS was more likely to lead to depressive-like behavior in rats,which may be closely related to the expression of CB1 and GluA1 in mPFC.展开更多
[Objectives]This study was conducted to improve the ecological and economic benefits of Pinus elliottii plantations in Pengchang Forest Farm, Jingmen City. [Methods] P. elliottii plantations in Pengchang Forest Farm i...[Objectives]This study was conducted to improve the ecological and economic benefits of Pinus elliottii plantations in Pengchang Forest Farm, Jingmen City. [Methods] P. elliottii plantations in Pengchang Forest Farm in Jingmen City were selected as the research object, and the appearance and quantitative characteristics of P. elliottii community were studied and analyzed by a sampling method. [Results] Phanerophytes were the most in the P. elliottii community, accounting for 50%. In the community, except P. elliottii, the importance values of native plants were higher. The order of species diversity of P. elliottii community in Pengchang Forest Farm was herb layer, tree layer and shrub layer. The stress resistance of the community was weak, and strong intraspecific competition existed in P. elliottii. It is recommended to thin P. elliottii trees with insufficient lighting, poor growth potential and severely damaged tree body, and interplant Phoebe zhennan after thinning the P. elliottii plantations, so as to create a coniferous and broad-leaved evergreen mixed forest. [Conclusions] This study provides scientific support for thinning, tending, and forest management of P. elliottii plantations.展开更多
The liquid leakage and weak solar absorption capacity of organic phase change materials(PCMs)seriously hinder the efficient utilization of solar energy and thermal energy storage.To address these issues,we prepared na...The liquid leakage and weak solar absorption capacity of organic phase change materials(PCMs)seriously hinder the efficient utilization of solar energy and thermal energy storage.To address these issues,we prepared nanoporous metal organic framework(Ni-MOF)for the vacuum infiltration of paraffin wax(PW),followed by the coating of solar-absorbing functional polydopamine(PDA)on the surface of PW@MOF for photothermal conversion and storage.As an efficient photon harvester,PDA coating endows PW@MOF/PDA composite PCMs with excellent photothermal conversion and storage properties due to the robust broadband solar absorption capability in the UV–vis region.Resultantly,our prepared PW@MOF/PDA composite PCMs exhibit a high photothermal conversion and storage efficiency of 91.2%,while that of PW@MOF composite PCMs is only zero.In addition,PW@MOF/PDA composite PCMs also exhibit excellent thermal stability,shape stability,energy storage stability,and photothermal conversion stability.More importantly,this coating strategy is universal by integrating different MOFs and solar absorbers,showing the potential to accelerate the major breakthroughs of high-efficiency MOF-based photothermal composite PCMs in solar energy utilization.展开更多
基金the National Natural Science Foundation of China(No.12172052 and No.12132003).
文摘Formation behaviors of rod-like reactive shaped charge penetrator(RRSCP)and their effects on damage capability are investigated by experiments and numerical simulations.The pulsed X-ray technology and a spaced aluminum/steel plate with the thicknesses of 5 mm/100 mm are used.Three types of sphericalsegment aluminum-polytetrafluoroethylene-copper(Al-PTFE-Cu)reactive liners with Cu contents of 0%,46.6%,and 66%are fabricated and tested.The experimental results show that the reactive liners can form excellent rod-shaped penetrators with tail skirts under the shaped charge effect,but the tail skirts disappear over time.Moreover,rupturing damage to the aluminum plate and penetration to the steel plate are caused by the RRSCP impact.From simulation analysis,the RRSCP is formed by a mechanically and chemically coupled response with the reactive liner activated by shock in its outer walls and bottom and then backward overturning,forming a leading reactive penetrator and a following chemical energy cluster.The unique formation structure determines the damage modes of the aluminum plate and the steel plate.Further analysis indicates that the formation behaviors and damage capability of Al-PTFE-Cu RRSCP strongly depend on Cu content.With increasing Cu content,the velocity,activation extent,and reaction extent of Al-PTFE-Cu RRSCP decrease,which contribute to elongation and alleviate the negative effects of chemical reactions on elongation,significantly increasing the length-diameter ratio and thus enhancing the capability of steel plate penetration.However,the lower activation extent and energetic density will weaken the RRSCP's capability of causing rupturing damage to the aluminum plate.
基金support received from the Beijing Municipal Natural Science Foundation(Grant No.1214022).
文摘To investigate the thermal response and initiation behavior of ternary fluoropolymer-matrix PTFE/Al/W reactive materials,a research combining shock loading tests and trans-scale modelling is conducted.On the basis of a good agreement of the numerically simulated and tested shock wave propagation,the significant impact of component ratios and particle sizes on the evolution of mesoscopic temperature,hot-spots and initiation is well characterized and analyzed.Results demonstrate that as the content of W increases,the range of mesoscopic high-temperature area increases and tends to distribute more uniform,while material with smaller W particles causes more intense particle deformation and larger temperature rise.The time to reach the critical temperature shows positive correlation to the content of W,while the critical temperature of hot-spots shows negative correlation to the particle size of W.For PTFE/Al/W of high density,with the increase of W particle size,the reaction rate decrease,however the time to reach the peak reaction rate shortens.
基金support from the Beijing Municipal Natural Science Foundation(Grant No.1214022).
文摘Combining the methods of theoretical,numerical and experimental,this research focuses on the jet formation behavior and optimization of trunconical hypercumulation shaped charge structure.With the three-stage division,formation theory of trunconical hypercumulation shaped charge jet is established based on micro element method.By dimensional analysis,main control parameters are identified and their effect on jet formation are analyzed.Through numerical modelling and orthogonal optimization method,influence of the factors and their levels over the indicators of jet tip velocity and jet length as well as order of the significance of each factor and level are obtained.Penetration experiments of trunconical hypercumulation shaped charge based on the orthogonal optimization reveals its advantage over traditional conical shaped charge structure,and finally determines the optimal influence factor level combination.The research and results would provide useful guide for the design and application of trunconical hypercumulation shaped charge structure.
基金funded by the National Key Research and Development Program of China(2021YFD1800400)the Beijing Natural Science Foundation(6222032)the Starting Grants Program for Young Talents at China Agricultural University,the 2115 Talent Development Program of China Agricultural University and Chinese Universities Scientific Fund.
文摘Background Alginate oligosaccharide(AOS)holds great potential as a novel feed supplement in farm animals.However,the effects of AOS on chicken health and the underlying mechanisms are not fully understood.This study aimed to optimize the enzymatic preparation of AOS by using bacterial alginate lyases expressed in yeast,investigate the effects of the prepared AOS on the growth performance and gut health of broiler chickens,and reveal the underlying mechanisms.Results Five alginate lyases from bacteria were cloned into Pichia pastoris GS115 and the alginate lyase PDE9 was expressed at relatively high yield,activity and stability in P.pastoris.Animal trials were carried out using 3201-day-old male Arbor Acres broilers(four groups;8 replicates/group×10 chicks/replicate)receiving either a basal diet or the same diet supplemented with 100,200 and 400 mg/kg PDE9-prepared AOS for 42 d.The results showed that dietary supplementation of 200 mg/kg AOS displayed the highest activity in promoting the birds’ADG and ADFI(P<0.05).AOS ameliorated the intestinal morphology,absorption function and barrier function,as indicated by the enhanced(P<0.05)intestinal villus height,maltase activity,and the expression of PEPT,SGLT1,ZNT1,and occludin.AOS also increased serum insulin-like growth factor-1,ghrelin(P<0.05),and growth hormone(P<0.1).Moreover,the concentrations of acetate,isobutyrate,isovalerate,valerate,and total SCFAs in cecum of birds fed AOS were significantly higher than the control birds(P<0.05).Metagenomic analysis indicated that AOS modulated the chicken gut microbiota structure,function,and microbial interactions and promoted the growth of SCFAs-producing bacteria,for example,Dorea sp.002160985;SCFAs,especially acetate,were found positively correlated with the chicken growth performance and growth-related hormone signals(P<0.05).We further verified that AOS can be utilized by Dorea sp.to grow and to produce acetate in vitro.Conclusions We demonstrated that the enzymatically produced AOS effectively promoted broiler chicken growth performance by modulating the chicken gut microbiota structure and function.For the first time,we established the connections among AOS,chicken gut microbiota/SCFAs,growth hormone signals and chicken growth performance.
基金financially supported by the Beijing Natural Science Foundation of China (No. 2232038)the National Natural Science Foundation of China (Nos. 52034002 and U1802253)the Fundamental Research Funds for the Central Universities (No. FRF-TT-19-001)
文摘Copper-indium-gallium-diselenide(CIGS)is a fast-evolving commercial solar cell.The firm demand for global carbon reduction and the rise of potential environmental threats necessitate spent CIGS solar cell recycling.In this paper,the sources and characteristics of valuable metals in spent CIGS solar cells were reviewed.The potential environmental impacts of CIGS,including service life,critical material,and material toxicity,were outlined.The main recovery methods of valuable metals in the various types of spent CIGS,including hydrometallurgy,pyrometallurgy,and comprehensive treatment processes,were compared and discussed.The mechanism of different recovery processes was summarized.The challenges faced by different recycling processes of spent CIGS were also covered in this review.Finally,the economic viability of the recycling process was assessed.The purpose of this review is to provide reasonable suggestions for the sustainable development of CIGS and the harmless disposal of spent CIGS.
基金Supported by Natural Science Foundation of Shandong Province(No.ZR2020MH172)。
文摘AIM:To examine the change of iris volume measured by CASIA2 anterior segment optical coherence tomography(ASOCT)in glaucoma patients with or without type 2 diabetes mellitus(T2DM)and explore if there is a correlation between hemoglobin A1c(HbA1c)level and iris volume.METHODS:In a cross-sectional study,72 patients(115 eyes)were divided into two groups:primary open angle glaucoma(POAG)group(55 eyes)and primary angle-closure glaucoma(PACG)group(60 eyes).Patients in each group were separately classified into patients with or without T2DM.Iris volume and glycosylated HbA1c level were measured and analyzed.RESULTS:In the PACG group,diabetic patients'iris volume was significantly lower than those of non-diabetics(P=0.02),and there was a significant correlation between iris volume and HbA1c level in the PACG group(r=-0.26,P=0.04).However,diabetic POAG patients'iris volume was noticeably higher than those of non-diabetics(P=0.01),and there was a significant correlation between HbA1c level and iris volume(r=0.32,P=0.02).CONCLUSION:Diabetes mellitus impact iris volume size,as seen by increased iris volume in the POAG group and decreased iris volume in the PACG group.In addition,iris volume is significantly correlated with HbA1c level in glaucoma patients.These findings imply that T2DM may compromise iris ultrastructure in glaucoma patients.
文摘<strong>Objectives:</strong> This study aims to present the characteristics of the undergraduate dental curriculum system using network modelling and visualisation analysis based on complex network theory, thus providing a theoretical foundation for the course development and curriculum reform. <strong>Methods:</strong> The correlation coefficient was used to quantify the intensity of the correlation between courses, and a visualisation complex network of the dental curriculum was built to explore the curriculum pattern from a dynamic perspective. Further, the statistical measurements of curriculum network were adopted to express the most relevant topological features. Subsequently, the minimum spanning tree and parallel coordinates plot were drawn to explore the curriculum community structure, quantify the key courses, and present different courses in time and space relationships. <strong>Results:</strong> The correlation analysis results show that the courses are closely related to each other. The main courses focus on pathology, pathophysiology, oral anatomy and physiology, closely connecting almost all medicine-related courses. The whole course network has an average degree value of 41.53, and a clustering coefficient of 0.78, indicating an obvious small-world characteristic. From the perspective of curriculum attributes, the number of public and theoretical courses was more than that of skills and practical courses. Moreover, the academic performance of skills and practical courses was lower than that of public and theoretical courses. <strong>Conclusion:</strong> The undergraduate dental courses have a progressive structure from basic professional knowledge to professional skills, which is reasonable for the dental education in China. However, some efforts towards curriculum reform based on this study are needed.
基金This work was supported by the National Natural Science Foundation of China(No.31270740).
文摘Seedlings of Taxus chinensis var.mairei were used as experimental materials to study the adaptation of Piriformospora indica to this plant under water stress.The materials were divided into two groups,namely,with or without inoculation with P.indica.Each group was subjected to four different levels of water stress.Vitality and physiological and biochemical indexes of the roots of T.chinensis var.mairei were regularly measured.Under water stress,T.chinensis var.mairei had significantly decreased root vitality;root vitality was higher in inoculated roots than in uninoculated roots.Under intense water stress,the inoculated roots had a higher soluble sugar content than the uninoculated roots.Under water stress,T.chinensis var.mairei experienced decreased activity of aerobic respiratory metabolic enzymes.The activity of anaerobic respiratory metabolic enzymes and alcohol dehydrogenase initially increased and then decreased,whereas that of lactate dehydrogenase increased.The inoculated roots had a higher activity of respiratory metabolic enzymes than the uninoculated roots.As water stress was further intensified,the roots had significantly decreased activity of aerobic respiratory metabolic enzymes and significantly increased activity of anaerobic respiratory metabolic enzymes.The activity of respiratory metabolic enzymes decreased faster in the uninoculated roots than in the inoculated roots.This study demonstrated that Piriformospora indica plays a positive role in enhancing the antihypoxic ability of T.chinensis var.mairei,thereby alleviating plant damage due to water stress.
基金Supported by the Natural Science Foundation of Shandong Province(No.ZR2020MH172)the Demonstration and Guidance Project of Science and Technology Benefiting People in Qingdao(No.20-3-4-39-nsh)。
文摘AIM:To investigate the association of axial length(AL),lens thickness(LT),and lens vault(LV)with postoperative anterior chamber angle metrics after laser peripheral iridotomy(LPI).METHODS:Prospective observational study of 69 patients(97 eyes)were diagnosed as primary angle-closure suspect(PACS),primary angle closure(PAC)or primary angle-closure glaucoma(PACG).AL,LT,anterior central chamber depth(ACD),angle opening distance(AOD),trabecular iris angle(TIA),and angle recess area(ARA)were measured before and 1 wk after LPI.The association between AL,LT,LV with ACD,AOD,TIA,ARA were analyzed by comparing the differences between preoperative and postoperative measurements for anterior segment biometric parameters.RESULTS:ACD,AOD,TIA,and ARA were significantly increased after LPI(all P<0.05).Greater LT was significantly associated with greater postoperative increases in ACD,AOD,TIA,and ARA(all P<0.05).AL was not significantly associated with changes of anterior segment biometric parameters.Greater LV was significantly associated with greater postoperative increases in ACD,AOD,and TIA(all P<0.05),but was not significantly associated with changes of ARA.CONCLUSION:Greater baseline LT and LV measurements are associated with greater increases in anterior segment biometric parameters after laser peripheral iridotomy.AL are not associated with the change of anterior segment biometric parameters.
基金This work is financially supported by Beijing Municipal Natural Science Foundation(No.L202012)the Open Research Project of the State Key Laboratory of Media Convergence and Communication,Communication University of China(No.SKLMCC2020KF008)the Fundamental Research Funds for the Central Universities(No.2020RC05).
文摘Fast data synchronization in wireless ad hoc networks is a challenging and critical problem.It is fundamental for efficient information fusion,control and decision in distributed systems.Previously,distributed data synchronization was mainly studied in the latency-tolerant distributed databases,or assuming the general model of wireless ad hoc networks.In this paper,we propose a pair of linear network coding(NC)and all-to-all broadcast based fast data synchronization algorithms for wireless ad hoc networks whose topology is under operator’s control.We consider both data block selection and transmitting node selection for exploiting the benefits of NC.Instead of using the store-and-forward protocol as in the conventional uncoded approach,a compute-and-forward protocol is used in our scheme,which improves the transmission efficiency.The performance of the proposed algorithms is studied under different values of network size,network connection degree,and per-hop packet error rate.Simulation results demonstrate that our algorithms significantly reduce the times slots used for data synchronization compared with the baseline that does not use NC.
基金This work is financially supported by the Beijing Municipal Natural Science Foundation(L202012)the Open Research Project of the State Key Laboratory of Media Convergence and Communication,Communication University of China(SKLMCC2020KF008)the Fundamental Research Funds for the Central Universities(2020RC05).The authors would like to thank Professor Ping Zhang(Member of the Chinese Academy of Engineering,Beijing University of Posts and Telecommunications)and Professor Quan Yu(Member of the Chinese Academy of Engineering,Peng Cheng Laboratory)for their insightful comments and suggestions.
文摘As a special type of mobile ad hoc network(MANET),the flying ad hoc network(FANET)has the potential to enable a variety of emerging applications in both civilian wireless communications(e.g.,5G and 6G)and the defense industry.The routing protocol plays a pivotal role in FANET.However,when designing the routing protocol for FANET,it is conventionally assumed that the aerial nodes move randomly.This is clearly inappropriate for a mission-oriented FANET(MO-FANET),in which the aerial nodes typically move toward a given destination from given departure point(s),possibly along a roughly deterministic flight path while maintaining a well-established formation,in order to carry out certain missions.In this paper,a novel cyber–physical routing protocol exploiting the particular mobility pattern of an MO-FANET is proposed based on cross-disciplinary integration,which makes full use of the missiondetermined trajectory dynamics to construct the time sequence of rejoining and separating,as well as the adjacency matrix for each node,as prior information.Compared with the existing representative routing protocols used in FANETs,our protocol achieves a higher packet-delivery ratio(PDR)at the cost of even lower overhead and lower average end-to-end latency,while maintaining a reasonably moderate and stable network jitter,as demonstrated by extensive ns-3-based simulations assuming realistic configurations in an MO-FANET.
基金Project supported by the National Natural Science Foundation of China(Grant No.11804137)the Natural Science Foundation of Shandong Province,China(Grant Nos.ZR2020YQ03 and ZR2018BA026).
文摘A new frustrated triangular lattice antiferromagnet Na_(2)BaNi(PO_(4))_(2) was synthesized by high temperature flux method.The two-dimensional triangular lattice is formed by the Ni^(2+)ions with S=1.Its magnetism is highly anisotropic with the Weiss constants θCW=6.615 K(H||c)and43.979 K(H⊥c).However,no magnetic ordering is present down to 0.3 K,reflecting strong geometric spin frustration.Our heat capacity measurements show substantial residual magnetic entropy existing below 0.3 K at zero field,implying the presence of low energy spin excitations.These results indicate that Na_(2)BaNi(PO_(4))_(2) is a potential spin liquid candidate with spin-1.
基金This work was supported by the National Natural Science Foundation of China[Grant No.31270740].
文摘Four different ratios of river sand,ceramic pellets,vermiculite and perlite(1:1),and field soil were selected as the substrates in this experiment,and four gradient levels of root waterlogging,half waterlogging,full waterlogging and normal were set to investigate the effects of different gradients of waterlogging stress on the root morphology of Taxus chinensis var.mairei seedlings under different substrates.In this study,the root anatomical structure of Taxus chinensis var.mairei under different waterlogging stress was observed by the paraffin section method.The roots of T.chinensis var.mairei were diarch,with no pith and resin canals.There was a large number of tannins in the pericycle of the aerial adventitious roots of seedlings adapted to waterlogging.Also,the endodermis has obvious casparian strip thickening,and there were 4-5 layers of large parenchymatous cells in the close to the inner side of the pericycle in the vascular cylinder,which could increase the storage capacity,and transport capacity of the root.Under the treatment of root waterlogging stress,the development of plant roots in the mixed substrate of vermiculite and,perlite was the earliest.Under half waterlogging stress,T.chinensis var.mairei seedlings treated with various substrates all could better adapt to the environment of waterlogging stress.Under the stress of fully waterlogging,the roots of seedlings planted in river sand substrate developed secondary growth.
基金National Natural Science Foundation of China(No.81803857)Autonomous Subject of Beijing University of Chinese Medicine(No.2018-JYBZZXJSJJ002)。
文摘Objective:To investigate the effects of chronic unpredictable mild stress(CUMS)on perineuronal nets(PNNs)andγ-aminobutyric acid(GABA)-ergic neurons in the medial prefrontal cortex(mPFC)of adult rats.Methods:28 rats were randomly divided into two groups.The model group adopted CUMS to establish a depression model,and the control group did not give any treatment.The density of PNNs and the percentage of PNNs positive(PNNs^(+))and parvalbumin positive(PV^(+))neurons in total PV^(+)neurons in the mPFC were detected by immunofluorescence.The protein expression of main components of PNNs,Aggrecan and Brevican,and GABA main synthase glutamic acid decarboxylase 67(GAD67)in the mPFC were detected by Western blot.Results:The density of PNNs and the percentage of PNNs^(+)and PV^(+)neurons in total PV^(+)neurons in the mPFC in the model group were decreased compared with the control group(P<0.05);The expression levels of PNNs component proteins Aggrecan and Brevican,and GABA main synthase GAD67 were also decreased in the model group(P<0.01).Conclusion:The levels of PNNs and GABA synthase GAD67 in the mPFC of rats were decreased after chronic unpredictable mild stress.
基金National Natural Science Foundation of China(No.81803857)Autonomous Subject of Beijing University of Chinese Medicine(No.2018-JYBZZ-XJSJJ002)。
文摘Objective:To explore the changes of cannabinoid receptor(CB1)and AMPA receptor subunit GluA1 in the medial prefrontal cortex(mPFC)of depression model rats induced by chronic unpredictable mild stress(CUMS).Methods:30 rats were randomly divided into three groups.The three-week model group was given a three-week CUMS model,the four-week model group was given a four-week CUMS model,and the control group was given no treatment.The behavior of rats were detected in each group,and the expression of CB1 and GluA1 protein in synaptosomes in mPFC brain region was detected by Western blot.Results:Compared with the control group,the surcose preference decreased,the feeding latency increased in the novel inhibition feeding test,and the immobility time increased in the forced swimming test in the four-week model group.However,after three weeks of CUMS,there was no obvious change in the behavior of rats compared with the control group,suggesting that four-week model of CUMS was successful.CUMS can reduce the expression level of CB1 and GluA1 protein in synaptosomes of mPFC brain area in four-week model group(P<0.05),but there was no significant difference between three-week model group and control group.Conclusion:Four-week CUMS was more likely to lead to depressive-like behavior in rats,which may be closely related to the expression of CB1 and GluA1 in mPFC.
文摘[Objectives]This study was conducted to improve the ecological and economic benefits of Pinus elliottii plantations in Pengchang Forest Farm, Jingmen City. [Methods] P. elliottii plantations in Pengchang Forest Farm in Jingmen City were selected as the research object, and the appearance and quantitative characteristics of P. elliottii community were studied and analyzed by a sampling method. [Results] Phanerophytes were the most in the P. elliottii community, accounting for 50%. In the community, except P. elliottii, the importance values of native plants were higher. The order of species diversity of P. elliottii community in Pengchang Forest Farm was herb layer, tree layer and shrub layer. The stress resistance of the community was weak, and strong intraspecific competition existed in P. elliottii. It is recommended to thin P. elliottii trees with insufficient lighting, poor growth potential and severely damaged tree body, and interplant Phoebe zhennan after thinning the P. elliottii plantations, so as to create a coniferous and broad-leaved evergreen mixed forest. [Conclusions] This study provides scientific support for thinning, tending, and forest management of P. elliottii plantations.
基金supported by the National Natural Science Foundation of China(52104254,22378104)the Natural Science Foundation of Hubei Province(2022CFB504)the Open Subject of Engineering Research Center for Clean Production of Textile Printing and Dyeing,Ministry of Education(2023GCZX008)。
基金This work was financially supported by the National Natural Science Foundation of China(No.51902025)Key Laboratory of Low-grade Energy Utilization Technologies and Systems(Chongqing University),Ministry of Education of China,Chongqing University(No.LLEUTS-202232)+4 种基金Fundamental Research Funds for the Jiangsu Province Universities(No.20KJB430037)Natural Science Foundation of Jiangsu Province(No.BK20220637)Fundamental Research Funds for the Central Universities(Nos.2019NTST29 and FRF-BD-20-07A)China Postdoctoral Science Foundation(Nos.2020T130060 and 2019M660520)Scientific and Technological Innovation Foundation of Shunde Graduate School,University of Science and Technology Beijing(No.BK20AE003).
文摘The liquid leakage and weak solar absorption capacity of organic phase change materials(PCMs)seriously hinder the efficient utilization of solar energy and thermal energy storage.To address these issues,we prepared nanoporous metal organic framework(Ni-MOF)for the vacuum infiltration of paraffin wax(PW),followed by the coating of solar-absorbing functional polydopamine(PDA)on the surface of PW@MOF for photothermal conversion and storage.As an efficient photon harvester,PDA coating endows PW@MOF/PDA composite PCMs with excellent photothermal conversion and storage properties due to the robust broadband solar absorption capability in the UV–vis region.Resultantly,our prepared PW@MOF/PDA composite PCMs exhibit a high photothermal conversion and storage efficiency of 91.2%,while that of PW@MOF composite PCMs is only zero.In addition,PW@MOF/PDA composite PCMs also exhibit excellent thermal stability,shape stability,energy storage stability,and photothermal conversion stability.More importantly,this coating strategy is universal by integrating different MOFs and solar absorbers,showing the potential to accelerate the major breakthroughs of high-efficiency MOF-based photothermal composite PCMs in solar energy utilization.
