In high-intensity electromagnetic warfare,radar systems are persistently subjected to multi-jammer attacks,including potentially novel unknown jamming types that may emerge exclusively under wartime conditions.These j...In high-intensity electromagnetic warfare,radar systems are persistently subjected to multi-jammer attacks,including potentially novel unknown jamming types that may emerge exclusively under wartime conditions.These jamming signals severely degrade radar detection performance.Precise recognition of these unknown and compound jamming signals is critical to enhancing the anti-jamming capabilities and overall reliability of radar systems.To address this challenge,this article proposes a novel open-set compound jamming cognition(OSCJC)method.The proposed method employs a detection-classification dual-network architecture,which not only overcomes the false alarm and misdetection issues of traditional closed-set recognition methods when dealing with unknown jamming but also effectively addresses the performance bottleneck of existing open-set recognition techniques focusing on single jamming scenarios in compound jamming environments.To achieve unknown jamming detection,we first employ a consistency labeling strategy to train the detection network using diverse known jamming samples.This strategy enables the network to acquire highly generalizable jamming features,thereby accurately localizing candidate regions for individual jamming components within compound jamming.Subsequently,we introduce contrastive learning to optimize the classification network,significantly enhancing both intra-class clustering and inter-class separability in the jamming feature space.This method not only improves the recognition accuracy of the classification network for known jamming types but also enhances its sensitivity to unknown jamming types.Simulations and experimental data are used to verify the effectiveness of the proposed OSCJC method.Compared with the state-of-the-art open-set recognition methods,the proposed method demonstrates superior recognition accuracy and enhanced environmental adaptability.展开更多
As a lightweight nanomaterial,Polyhedral Oligomeric Silsesquioxane(POSS)is widely applied to ablation resistance modification of Ethylene-Propylene-Dine Monomer(EPDM)insulation layer in aerospace propulsion thermal pr...As a lightweight nanomaterial,Polyhedral Oligomeric Silsesquioxane(POSS)is widely applied to ablation resistance modification of Ethylene-Propylene-Dine Monomer(EPDM)insulation layer in aerospace propulsion thermal protection system.However,various structures of POSS can form different crosslinked structures within the EPDM,which can affect the insulation layer properties.Various functionality POSS,Mono-Norbornene POSS(MN-POSS)and TriNorbornene POSS(TN-POSS),were designed and synthesized to obtain crosslinked-modified EPDMs with enhanced mechanical properties and ablation resistance simultaneously,and the relationship between POSS functionality,the mechanical properties,ablation resistance,heat-shielding and thermal decomposition of EPDM/Aramid Fiber(AF)composites were explored comprehensively.MN-POSS and TN-POSS increased the tensile strength of EPDM composites by 25.3%and 75.2%respectively,reduced the linear ablation rate by 37.7%and 33.7%respectively,and reduced the back temperatures by 3.9℃ and 3.3℃ respectively.Under conditions of equal cage structure(T8),the suspended crosslinked structure caused by MN-POSS exhibited better ablation resistance and heat-shielding performance as well as thermal decomposition,and the anchored crosslinked structure caused by TN-POSS exhibited better tensile strength.The structural transformation indicates that the POSS nanocages can be transformed into a ceramic structure in cruel environments to resist the erosion of heat flow and enhance the ablation resistance of insulation layer.展开更多
The exponential growth of antibiotic-resistant bacteria and antibiotic-resistant genes(ARGs)in soil-crop systems in recent years has posed a great challenge to ecological security and human health.While many studies h...The exponential growth of antibiotic-resistant bacteria and antibiotic-resistant genes(ARGs)in soil-crop systems in recent years has posed a great challenge to ecological security and human health.While many studies have documented the residues of ARGs in soils and crops,but little is known about who drives the proliferation of ARGs in farming systems and what their underlying mechanisms are.Herein,we explored the occurrence and proliferating behavior of ARGs in soil-crop environments in terms of root secretions and plant volatiles.This review highlighted that plant root secretions and volatile organic compounds(VOCs)served as key substances mediating the development of antibiotic resistance in the soil-crop system.Still,there is controversy here as to plant root secretions promote the ARGs proliferation or inhibit.Some studies indicated that root secretions can suppress the colonization of ARGs,mainly attributed by the production of bluntedmetabolic enzymes and blocking of cellular exocytosis systems.Whereas the others have evidenced that root secretions can promote ARGs proliferation,primarily by altering the structure of microbial communities to influence species interactions and thus indirectly affect the proliferation of ARGs.Also,VOCs can act as molecular signals to convey antibiotic resistance information to their neighbors,which in turn drive the up-regulation of ARGs expression.Even so,the mechanism by which VOC-driven antibiotic resistance acquisition and proliferation need to be further probed.Overall,this review contributed to the development of products and technologies to impede the ARGs proliferation in agricultural environment.展开更多
Obtaining room-temperature superconductors has long been a research hotspot in the field of condensed matter physics.Previous studies have shown that doping strategies can effectively enhance the superconducting prope...Obtaining room-temperature superconductors has long been a research hotspot in the field of condensed matter physics.Previous studies have shown that doping strategies can effectively enhance the superconducting properties of materials.In this work,we employed first-principles calculations combined with the particle swarm optimization method to explore the structural possibilities of the Ca-doped As-H ternary system and to calculate the electronic and superconducting properties of the newly identified structures.Two thermodynamically stable hydrides were found under high pressure.The P4/nmm-Ca_(2)AsH_(4)phase remains thermodynamically stable within the pressure range of 90-200 GPa,while the Cc-Ca_(2)AsH_(6)phase exhibits stability over a broader range of 79-200 GPa.Electron-phonon coupling analysis indicates that the superconducting critical temperatures(Tc)of P4/nmm-Ca_(2)AsH_(4)and Cc-Ca_(2)AsH_(6)are 11 K and 16 K at 100 GPa,respectively.The incorporation of Ca significantly reduces the thermodynamic stability pressure of As-H compounds with higher hydrogen content,thereby improving their synthetic accessibility.展开更多
Currently,in almost all work on transition metal-mediated transformation of dinitrogen(N_(2))into organic compounds,the C-N bond formation steps are fulfilled through the interaction between metal-dinitrogen[M-N_(2)]c...Currently,in almost all work on transition metal-mediated transformation of dinitrogen(N_(2))into organic compounds,the C-N bond formation steps are fulfilled through the interaction between metal-dinitrogen[M-N_(2)]complexes and carbon based substrates.The preparation steps of[M-N_(2)]complexes are incompatible with the reaction conditions of the N−C bond formation,which has prevented catalysis.Herein,we report a chemical cycle that does not involve the preparation steps of[M-N_(2)]complexes.In the presence of Ni(CO)_(4) and SbF_(5) catalysts,this chemical cycle can convert mixed phosphonium-sulfonium bisylide R_(3)P=C=SPh_(2) and N_(2) into diazomethylenephosphoranes R_(3)P=C=N_(2).The C-N bond formation steps in this work are achieved through the direct reaction of N_(2) molecules with carbene 3,which is a metal-carbon based[M-C]complex.The computed free energy barrier for the reaction between carbene 3 and N_(2) is 24.06 kcal/mol,indicating that this reaction can occur at room temperature.Theoretical calculations show that the above chemical cycle is feasible in terms of kinetics and thermodynamics and is a true catalytic system for directly introducing N_(2) into organic compounds under mild conditions.Additionally,compared to traditional carbenes CR_(2) with two electron-sharing bonds between carbon and substituent R,the predicted carbene 3'(R_(2)P^(Me)→C:→Ni(CO)_(3))and carbene 3(R_(2)P^(Me)→C:→Ni(CO)_(2))in this work have unique electronic structures,which feature two P→C and C→Ni donor-acceptor bonds.The weak C→Ni bonds of carbene 3'and carbene 3 are critical for the regeneration of transition metal catalysts Ni(CO)_(4).This also means that the predicted carbene 3'and carbene 3 will have richer chemical properties to be discovered than traditional carbene CR_(2).This work also preliminarily predicted that carbene 3'has the potential to activate CO,indicating that this work may open the door to activating other important small molecules.展开更多
Given that a large amount of crude oil remains on the surface of rocks and is difficult to produce after conventional waterflooding,a new superwetting oil displacement system incorporating the synergy between a hydrox...Given that a large amount of crude oil remains on the surface of rocks and is difficult to produce after conventional waterflooding,a new superwetting oil displacement system incorporating the synergy between a hydroxyl anion compound(1OH-1C)and an extended surfactant(S-C_(13)PO_(13)S)was designed.The interfacial tension,contact angle and emulsification performance of the system were measured.The oil displacement effects and improved oil recovery(IOR)mechanisms of 1OH-1C,S-C_(13)PO_(13)S and their compound system were investigated by microscopic visualization oil displacement experiments and core displacement experiments.The results show that 1OH-1C creates a superwetting interface and electrostatic separation pressure on the solid surface,which destroys the strong interactions between crude oil and quartz to peel off the oil film.S-C_(13)PO_(13)S has low interfacial tension,which can promote the flow of remaining oil and emulsify it into oil-in-water emulsions.The compound system of 1OH-1C and S-C_(13)PO_(13)S has both superwettability and low IFT,which can effectively improve oil recovery through a synergistic effect.The oil displacement experiment of low-permeability natural core shows that the compound solution can increase the oil recovery by 16.4 percentage points after waterflooding.This new high-efficiency system is promising for greatly improving oil recovery in low-permeability reservoirs.展开更多
OBJECTIVE:To systematically assess the safety and effectiveness of Compound E’jiao Jiang(复方阿胶浆,CEJ)for treating leukopenia.METHODS:Four English and four Chinese databases were searched for randomized controlled ...OBJECTIVE:To systematically assess the safety and effectiveness of Compound E’jiao Jiang(复方阿胶浆,CEJ)for treating leukopenia.METHODS:Four English and four Chinese databases were searched for randomized controlled trials(RCTs)on CEJ for treating leukopenia up to July 1,2024.Two researchers independently screened the studies and extracted necessary data.Methodological quality and risk of bias were assessed using the Cochrane risk-of-bias tool.Articles eligible for Meta-analysis were analyzed using RevMan.RESULTS:A total of 28 RCTs involving 2041 participants were included,with 1034 in the experimental group and 1007 in the control group.The Meta-analysis showed a significant effect of CEJ in treating leukopenia caused by tumor and immune diseases(three RCTs)[risk ratio(RR)=1.17,95%confidence interval(CI)(1.08,1.27),P=0.0002,I^(2)=35%].The combination of CEJ and Western Medicine showed superior results in terms of white blood cell(WBC)counts(fifteen RCTs)[mean difference(MD)=1.12,95%CI(0.83,1.42),P<0.00001,I^(2)=88%],Karnofsky Performance Status(KPS)levels(seven RCTs)[RR=1.39,95%CI(1.25,1.55),P<0.00001,I^(2)=36%],and mitigation of bone marrow toxicity(eleven RCTs)[RR=0.61,95%CI(0.54,0.69),P<0.00001,I^(2)=24%]compared to Western Medicine alone.Adverse events mainly included gastrointestinal and digestive reactions associated with chemotherapy drugs.CONCLUSION:CEJ alone or in combination with Western Medicine for treating leukopenia caused by tumor and immune diseases improved WBC counts,clinical efficacy,and quality of life.It also reduced bone marrow toxicity-induced leukopenia,enhanced the efficacy of chemotherapy while reducing its toxicity,and alleviated symptoms.No significant adverse events were reported in the RCTs,indicating favorable efficacy and safety.The Grading of Recommendations Assessment,Development and Evaluation assessment indicated a low level of evidence for CEJ in improving leukocyte elevation efficacy,KPS levels,and myelosuppressive toxicity.Therefore,large-scale,high-quality,rigorous multicenter double-blind controlled trials are recommended to strengthen the evidence level.展开更多
In view of the existing composite planting cannot do independent control of fertilizer rate for each row,and fertilizer is easy to moisture solidification caking and rely on a single way to measure the speed of inaccu...In view of the existing composite planting cannot do independent control of fertilizer rate for each row,and fertilizer is easy to moisture solidification caking and rely on a single way to measure the speed of inaccurate problems,a split-drive variable fertilizer application system was designed for soybean and maize strip cropping composites.It includes roller crushing bi-directional spiral fertilizer discharger,split-drive variable fertilizer application system and‘GNSS+encoder’dual speed measurement system.By modeling agglomerated fertilizer particles,discrete element simulation was carried out to analyze the crushing effect.The speed measurement error variation folds of both GNSS and encoder under different speed conditions were obtained through field speed measurement tests.Finally,4.5 km/h was identified as the switching point between the two speed measurements.Through bench testing,a mathematical relationship model was developed for the soybean and maize belts in terms of‘Fertilizer Application Rate-Operating Travel Speed-Metering Mechanism Rotor Speed’,and the results are presented in the table below.Fertilizer discharge consistency was verified for fertilizer dischargers.Field trials were conducted,and the results show:The soybean belt had a maximum error of 4.81%at a fertilizer application rate of 150 kg/hm2 and an operating speed of 5 km/h;the maximum error in the corn belt was 4.67%at a fertilizer application rate of 600 kg/hm2 and operating speed of 4 km/h.Both have a maximum error of less than 5%,which meets the requirements for variable fertilizer application.展开更多
Achieving room-temperature superconductivity has been an enduring scientific quest,while hydrogen-rich compounds have emerged as highly promising candidates.Here,we systematically investigated the thermodynamic stabil...Achieving room-temperature superconductivity has been an enduring scientific quest,while hydrogen-rich compounds have emerged as highly promising candidates.Here,we systematically investigated the thermodynamic stability,crystal structure,electronic properties,and superconductivity within the ternary Y-Hf-H system under high pressure.Several distinct hydrides have been revealed,in which the hydrogen atoms are present in various hydrogenic motifs.A15-type hydride P_(m)3-YHfH_(6)with isolated H−is predicted to be dynamically stabilized down to 10GPa.The H atoms form pentagonal graphene-like layered-H10 anions in the Hf plane of P6-YHfH_(19),with aT_(c)of 95K at 100GPa.There are H cages in C_(mmm)-Y_(3)HfH_(24),and attributed to the robust electron–phonon coupling and high electronic density of states of hydrogen at the Fermi level,it demonstrates near-room temperature superconductivity with a T_(c)of 275K at 250GPa.Our work makes contributions to the understanding of the fundamental properties of ternary hydrides under high pressure and provides essential references for further research in this field.展开更多
The phase equilibria and compositions in Mg-rich comer at 300℃ were determined in the Mg-Zn-A1 ternary system through the equilibrated alloy method by using X-ray diffraction （XRD） and scanning electron microscopy ...The phase equilibria and compositions in Mg-rich comer at 300℃ were determined in the Mg-Zn-A1 ternary system through the equilibrated alloy method by using X-ray diffraction （XRD） and scanning electron microscopy （SEM） assisted with energy dispersive spectroscopy of X-ray （EDS）. The results show that there exist three three-phase regions consisted of a-Mg＋Mg17A112（7）＋A15Mg11Zn4（φ）, a-Mg＋Mga2（Al, Zn）49（r）＋A15MgllZn4（φ） and a-Mg＋MgZn＋Mg32（A1, Zn）49（r）, respectively. The intermetallic compounds in equilibrium with a-Mg phase all have large composition ranges, not appear to be linear. At the same time, both zinc and aluminum are soluble in the a-Mg solid solution, with which the compounds are in equilibrium.展开更多
The phase equilibria in Co-rich region of Co-Ti-Ta system were studied.The microstructure and XRD analysis together with EDS determination show that L12 type Co3Ti phase and Laves_C36_Co3Ta phase get equilibrium with ...The phase equilibria in Co-rich region of Co-Ti-Ta system were studied.The microstructure and XRD analysis together with EDS determination show that L12 type Co3Ti phase and Laves_C36_Co3Ta phase get equilibrium with α-Co phase from 1 000 to 1 200 ℃.The Co3Ti phase possesses a solubility of Ta higher than 10%,and the addition of Ta stabilizes the Co3Ti phase.The isothermal sections of the Co-Ti-Ta system in the Co-rich region at 1 000,1 100 and 1 200 ℃ were constructed according to the result.展开更多
Taking AuCu3-type sublattice system as an example, three discoveries have been presented: First, the third barrier hindering the progress in metal materials science is that researchers have got used to recognizing exp...Taking AuCu3-type sublattice system as an example, three discoveries have been presented: First, the third barrier hindering the progress in metal materials science is that researchers have got used to recognizing experimental phenomena of alloy phase transitions during extremely slow variation in temperature by equilibrium thinking mode and then taking erroneous knowledge of experimental phenomena as selected information for establishing Gibbs energy function and so-called equilibrium phase diagram. Second, the equilibrium holographic network phase diagrams of AuCu3-type sublattice system may be used to describe systematic correlativity of the composition?temperature-dependent alloy gene arranging structures and complete thermodynamic properties, and to be a standard for studying experimental subequilibrium order-disorder transition. Third, the equilibrium transition of each alloy is a homogeneous single-phase rather than a heterogeneous two-phase, and there exists a single-phase boundary curve without two-phase region of the ordered and disordered phases; the composition and temperature of the top point on the phase-boundary curve are far away from the ones of the critical point of the AuCu3 compound.展开更多
Taking Au3Cu-type sublattice system as an example, three discoveries have been presented. First, the fourth barrier to hinder the progress of metal materials science is that today’s researchers do not understand that...Taking Au3Cu-type sublattice system as an example, three discoveries have been presented. First, the fourth barrier to hinder the progress of metal materials science is that today’s researchers do not understand that the Gibbs energy function of an alloy phase should be derived from Gibbs energy partition function constructed of alloy gene sequence and their Gibbs energy sequence. Second, the six rules for establishing alloy gene Gibbs energy partition function have been discovered, and it has been specially proved that the probabilities of structure units occupied at the Gibbs energy levels in the degeneracy factor for calculating configuration entropy should be degenerated as ones of component atoms occupied at the lattice points. Third, the main characteristics unexpected by today’s researchers are as follows. There exists a single-phase boundary curve without two-phase region coexisting by the ordered and disordered phases. The composition and temperature of the top point on the phase-boundary curve are far away from those of the critical point of the Au3Cu compound; At 0 K, the composition of the lowest point on the composition-dependent Gibbs energy curve is notably deviated from that of the Au3Cu compounds. The theoretical limit composition range of long range ordered Au3Cu-type alloys is determined by the first jumping order degree.展开更多
The phase equilibria and compositions at the Mg-rich corner of the Mg?Zn?Al ternary system at 335 °C were systemically investigated through the equilibrated alloy method by using X-ray diffraction (XRD) and scann...The phase equilibria and compositions at the Mg-rich corner of the Mg?Zn?Al ternary system at 335 °C were systemically investigated through the equilibrated alloy method by using X-ray diffraction (XRD) and scanning electron microscopy (SEM) assisted with energy dispersive spectroscopy of X-ray (EDS). It is experimentally testified that theα-Mg solid solution is not in equilibrium with the Mg32(Al, Zn)49 (τ) ternary intermetallic compound orq quasicrystalline phase, but only in equilibrium with one ternary intermetallic compound Al5Mg11Zn4 (φ). The whole composition range of theφ phase was also obtained at 335 °C, i.e., 52.5%?56.4% Mg, 13.6%?24.0% Al, 19.6%?33.9% Zn (mole fraction). The solubility of Al in the MgZn phase is remarkably more than that in the Mg7Zn3 phase, and the maximum is about 8.6% Al. Aluminum and zinc are simultaneously soluble in theα-Mg solid solution.展开更多
This paper analyzes the compound attractor structure of a new three-dimensional autonomous chaotic system. First, it is found that there exist five equilibria in the chaotic system, and the stabilities of these equili...This paper analyzes the compound attractor structure of a new three-dimensional autonomous chaotic system. First, it is found that there exist five equilibria in the chaotic system, and the stabilities of these equilibria are discussed under a constant scalar control input parameter m. Secondly, the trajectories of the attractors on a y-z plane are examined, the reasons why these trajectories can exist or disappear are also described. Finally, the forming procedure of the different scrolls chaotic attractor is explored by computer simulations when the parameter m is varied. It is shown that the new chaotic attractor has a compound structure, it can evolve to other three-dimensional autonomous chaotic systems. The results of theoretical analysis and simulation are helpful for better understanding of other similar chaotic systems.展开更多
[Objective]Preservation and waterproof treatment are two crucial parts in wood protection, which can not only extend the service time, but also expand the application range of wood products. [Method] This work combine...[Objective]Preservation and waterproof treatment are two crucial parts in wood protection, which can not only extend the service time, but also expand the application range of wood products. [Method] This work combined CA with paraffin wax emulsion to treat wood samples, and basic properties of the compound system, such as stability （storage stability and centrifugal stability）, particle size and pH val-ue, and water repel ency （water absorption, shrinkage and swel ing） of treated sam-ples were investigated. [Result and Conclusion] 1） the compound systems of CA and paraffin latex had a favorable miscibility and stability; 2） compared with untreated wood, CA-treated samples showed poor water repel ing properties, whereas samples treated with the compound systems indicated an obvious reduction in water absorp-tion, and the shrinkage and swel ing of them were improved as wel .展开更多
Multivariables, strong coupling, nonlinearity, and large delays characterize the boiler-turbine coordinated control systems for ship power equipment. To better deal with these conditions, a compound control strategy b...Multivariables, strong coupling, nonlinearity, and large delays characterize the boiler-turbine coordinated control systems for ship power equipment. To better deal with these conditions, a compound control strategy based on a support vector machine （SVM） with inverse identification was proposed and applied to research simulating coordinated control systems. This method combines SVM inverse control and fuzzy control, taking advantage of the merits of SVM inverse controls which can be designed easily and have high reliability, and those of fuzzy controls, which respond rapidly and have good anti-jamming capability and robustness. It ensures the controller can be controlled with near instantaneous adjustments to maintain a steady state, even if the SVM is not trained well. The simulation results show that the control quality of this fuzzy-SVM compound control algorithm is high, with good performance in dynamic response speed, static stability, restraint of overshoot, and robustness.展开更多
The finding of the compound structure of a new four-scrolls chaotic system is reported, which is obtained by merging together two symmetrical attractors. And the two symmetrical attractors are generated only by adding...The finding of the compound structure of a new four-scrolls chaotic system is reported, which is obtained by merging together two symmetrical attractors. And the two symmetrical attractors are generated only by adding a constant gain to the original system. Also, the forming procedure of the new four-scrolls chaotic attractor is explored and the relation between the constant gain and the properties of the system is given.展开更多
The phase equilibria and compositions in Mg-rich side at 300 ℃ were investigated in Mg-Zn-Ca ternary system through the equilibrated alloy method by using scanning electron microscopy,electron probe microanalysis,X-r...The phase equilibria and compositions in Mg-rich side at 300 ℃ were investigated in Mg-Zn-Ca ternary system through the equilibrated alloy method by using scanning electron microscopy,electron probe microanalysis,X-ray diffraction and transmission electron microscopy.The results show that two ternary compounds T1 and T2 can be in equilibrium with the Mg-based solid solution in Mg-Zn-Ca system.T1 phase is a linear compound with the composition region（molar fraction） of 15% Ca,20.5%-48.9% Zn and balanced Mg at 300 ℃.Its hexagonal structure parameters decrease with increasing Zn content,i.e.a=0.992-0.945 nm,c=1.034-1.003 nm.T2 phase has hexagonal structure with the composition region of 26.4%-28.4% Mg,63.2%-65.5% Zn and 7.1%-8.4% Ca.At 300 ℃,the solubility of Zn in the Mg-based solid solution increases for the addition of Ca,the maximum solubility of Zn is 3.7%.Three-phase fields consisting of--Mg＋Mg2Ca＋T1,--Mg＋T1＋T2,--Mg＋T2＋MgZn and MgZn＋T2＋Mg2Zn3 exist in the Mg-Zn-Ca system at 300 ℃.展开更多
By analyzing the target's motion pattern, in terms of the requirement for the performance indexes of the follow up system, the structure changing control and time optimal theory is proposed. The system's co...By analyzing the target's motion pattern, in terms of the requirement for the performance indexes of the follow up system, the structure changing control and time optimal theory is proposed. The system's control scheme from three different aspects(the dynamic response simulation, compound control simulation and dynamic tracking simulation) is also studied. And all the results proved the feasibility of the synthetical utilization of the open loop control, speed decreased control and position closed loop control.展开更多
文摘In high-intensity electromagnetic warfare,radar systems are persistently subjected to multi-jammer attacks,including potentially novel unknown jamming types that may emerge exclusively under wartime conditions.These jamming signals severely degrade radar detection performance.Precise recognition of these unknown and compound jamming signals is critical to enhancing the anti-jamming capabilities and overall reliability of radar systems.To address this challenge,this article proposes a novel open-set compound jamming cognition(OSCJC)method.The proposed method employs a detection-classification dual-network architecture,which not only overcomes the false alarm and misdetection issues of traditional closed-set recognition methods when dealing with unknown jamming but also effectively addresses the performance bottleneck of existing open-set recognition techniques focusing on single jamming scenarios in compound jamming environments.To achieve unknown jamming detection,we first employ a consistency labeling strategy to train the detection network using diverse known jamming samples.This strategy enables the network to acquire highly generalizable jamming features,thereby accurately localizing candidate regions for individual jamming components within compound jamming.Subsequently,we introduce contrastive learning to optimize the classification network,significantly enhancing both intra-class clustering and inter-class separability in the jamming feature space.This method not only improves the recognition accuracy of the classification network for known jamming types but also enhances its sensitivity to unknown jamming types.Simulations and experimental data are used to verify the effectiveness of the proposed OSCJC method.Compared with the state-of-the-art open-set recognition methods,the proposed method demonstrates superior recognition accuracy and enhanced environmental adaptability.
基金the support from the Xianyang Major Scientific and Technological Innovation Special Project—University and Research Institute“Three-Item Reform”Technology Transfer Project,China(No.D5140240003)the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University,China(No.CX2023093)。
文摘As a lightweight nanomaterial,Polyhedral Oligomeric Silsesquioxane(POSS)is widely applied to ablation resistance modification of Ethylene-Propylene-Dine Monomer(EPDM)insulation layer in aerospace propulsion thermal protection system.However,various structures of POSS can form different crosslinked structures within the EPDM,which can affect the insulation layer properties.Various functionality POSS,Mono-Norbornene POSS(MN-POSS)and TriNorbornene POSS(TN-POSS),were designed and synthesized to obtain crosslinked-modified EPDMs with enhanced mechanical properties and ablation resistance simultaneously,and the relationship between POSS functionality,the mechanical properties,ablation resistance,heat-shielding and thermal decomposition of EPDM/Aramid Fiber(AF)composites were explored comprehensively.MN-POSS and TN-POSS increased the tensile strength of EPDM composites by 25.3%and 75.2%respectively,reduced the linear ablation rate by 37.7%and 33.7%respectively,and reduced the back temperatures by 3.9℃ and 3.3℃ respectively.Under conditions of equal cage structure(T8),the suspended crosslinked structure caused by MN-POSS exhibited better ablation resistance and heat-shielding performance as well as thermal decomposition,and the anchored crosslinked structure caused by TN-POSS exhibited better tensile strength.The structural transformation indicates that the POSS nanocages can be transformed into a ceramic structure in cruel environments to resist the erosion of heat flow and enhance the ablation resistance of insulation layer.
基金supported by the Youth innovation Program of Chinese Academy of Agricultural Sciences(No.Y2023QC32)the foundation of Tianjin Natural Science Foundation(No.22JCQNJC01460)the Science and Technology Innovation Project of Chinese Academy of Agricultural Sciences(Agro-Environmental Protection Institute,Ministry of Agricultural and Rural Affairs)and the Youth Talent Project of Agro-Environmental Protection Institute,Ministry of Agricultural and Rural Affairs(Xu Yan).
文摘The exponential growth of antibiotic-resistant bacteria and antibiotic-resistant genes(ARGs)in soil-crop systems in recent years has posed a great challenge to ecological security and human health.While many studies have documented the residues of ARGs in soils and crops,but little is known about who drives the proliferation of ARGs in farming systems and what their underlying mechanisms are.Herein,we explored the occurrence and proliferating behavior of ARGs in soil-crop environments in terms of root secretions and plant volatiles.This review highlighted that plant root secretions and volatile organic compounds(VOCs)served as key substances mediating the development of antibiotic resistance in the soil-crop system.Still,there is controversy here as to plant root secretions promote the ARGs proliferation or inhibit.Some studies indicated that root secretions can suppress the colonization of ARGs,mainly attributed by the production of bluntedmetabolic enzymes and blocking of cellular exocytosis systems.Whereas the others have evidenced that root secretions can promote ARGs proliferation,primarily by altering the structure of microbial communities to influence species interactions and thus indirectly affect the proliferation of ARGs.Also,VOCs can act as molecular signals to convey antibiotic resistance information to their neighbors,which in turn drive the up-regulation of ARGs expression.Even so,the mechanism by which VOC-driven antibiotic resistance acquisition and proliferation need to be further probed.Overall,this review contributed to the development of products and technologies to impede the ARGs proliferation in agricultural environment.
基金supported by the National Natural Science Foundation of China(Grant Nos.12204280 and 12147135)the Natural Science Foundation of Shandong Province(Grant No.ZR202103010004)+1 种基金the China Postdoctoral Science Foun-dation(Certificate Nos.2023T160396 and 2021M691980)the Youth Innovation Team Plan of Colleges and Universities in Shandong Province(Grant No.2023KJ350).
文摘Obtaining room-temperature superconductors has long been a research hotspot in the field of condensed matter physics.Previous studies have shown that doping strategies can effectively enhance the superconducting properties of materials.In this work,we employed first-principles calculations combined with the particle swarm optimization method to explore the structural possibilities of the Ca-doped As-H ternary system and to calculate the electronic and superconducting properties of the newly identified structures.Two thermodynamically stable hydrides were found under high pressure.The P4/nmm-Ca_(2)AsH_(4)phase remains thermodynamically stable within the pressure range of 90-200 GPa,while the Cc-Ca_(2)AsH_(6)phase exhibits stability over a broader range of 79-200 GPa.Electron-phonon coupling analysis indicates that the superconducting critical temperatures(Tc)of P4/nmm-Ca_(2)AsH_(4)and Cc-Ca_(2)AsH_(6)are 11 K and 16 K at 100 GPa,respectively.The incorporation of Ca significantly reduces the thermodynamic stability pressure of As-H compounds with higher hydrogen content,thereby improving their synthetic accessibility.
文摘Currently,in almost all work on transition metal-mediated transformation of dinitrogen(N_(2))into organic compounds,the C-N bond formation steps are fulfilled through the interaction between metal-dinitrogen[M-N_(2)]complexes and carbon based substrates.The preparation steps of[M-N_(2)]complexes are incompatible with the reaction conditions of the N−C bond formation,which has prevented catalysis.Herein,we report a chemical cycle that does not involve the preparation steps of[M-N_(2)]complexes.In the presence of Ni(CO)_(4) and SbF_(5) catalysts,this chemical cycle can convert mixed phosphonium-sulfonium bisylide R_(3)P=C=SPh_(2) and N_(2) into diazomethylenephosphoranes R_(3)P=C=N_(2).The C-N bond formation steps in this work are achieved through the direct reaction of N_(2) molecules with carbene 3,which is a metal-carbon based[M-C]complex.The computed free energy barrier for the reaction between carbene 3 and N_(2) is 24.06 kcal/mol,indicating that this reaction can occur at room temperature.Theoretical calculations show that the above chemical cycle is feasible in terms of kinetics and thermodynamics and is a true catalytic system for directly introducing N_(2) into organic compounds under mild conditions.Additionally,compared to traditional carbenes CR_(2) with two electron-sharing bonds between carbon and substituent R,the predicted carbene 3'(R_(2)P^(Me)→C:→Ni(CO)_(3))and carbene 3(R_(2)P^(Me)→C:→Ni(CO)_(2))in this work have unique electronic structures,which feature two P→C and C→Ni donor-acceptor bonds.The weak C→Ni bonds of carbene 3'and carbene 3 are critical for the regeneration of transition metal catalysts Ni(CO)_(4).This also means that the predicted carbene 3'and carbene 3 will have richer chemical properties to be discovered than traditional carbene CR_(2).This work also preliminarily predicted that carbene 3'has the potential to activate CO,indicating that this work may open the door to activating other important small molecules.
基金Supported by the National Key R&D Program of China(2019YFA0708700,2023YFF0614100)CNPC Major Science and Technology Project(2021ZZ01,2023ZZ04).
文摘Given that a large amount of crude oil remains on the surface of rocks and is difficult to produce after conventional waterflooding,a new superwetting oil displacement system incorporating the synergy between a hydroxyl anion compound(1OH-1C)and an extended surfactant(S-C_(13)PO_(13)S)was designed.The interfacial tension,contact angle and emulsification performance of the system were measured.The oil displacement effects and improved oil recovery(IOR)mechanisms of 1OH-1C,S-C_(13)PO_(13)S and their compound system were investigated by microscopic visualization oil displacement experiments and core displacement experiments.The results show that 1OH-1C creates a superwetting interface and electrostatic separation pressure on the solid surface,which destroys the strong interactions between crude oil and quartz to peel off the oil film.S-C_(13)PO_(13)S has low interfacial tension,which can promote the flow of remaining oil and emulsify it into oil-in-water emulsions.The compound system of 1OH-1C and S-C_(13)PO_(13)S has both superwettability and low IFT,which can effectively improve oil recovery through a synergistic effect.The oil displacement experiment of low-permeability natural core shows that the compound solution can increase the oil recovery by 16.4 percentage points after waterflooding.This new high-efficiency system is promising for greatly improving oil recovery in low-permeability reservoirs.
基金Supported by The Qihuang Scholars Support Program of the National Administration of Traditional Chinese Medicinet:2021 Qihuang Scholars Support Project(National Chinese Medicine Teaching Letter[2022]6)National Traditional Medicine Administration's Project for Establishing National Famous and Elderly Traditional Medicine Transmission Workshops:Xie Yanming National Famous Traditional Chinese Medicine Expert Transmission Studio(National Chinese Medicine Education Letter[2022]75)。
文摘OBJECTIVE:To systematically assess the safety and effectiveness of Compound E’jiao Jiang(复方阿胶浆,CEJ)for treating leukopenia.METHODS:Four English and four Chinese databases were searched for randomized controlled trials(RCTs)on CEJ for treating leukopenia up to July 1,2024.Two researchers independently screened the studies and extracted necessary data.Methodological quality and risk of bias were assessed using the Cochrane risk-of-bias tool.Articles eligible for Meta-analysis were analyzed using RevMan.RESULTS:A total of 28 RCTs involving 2041 participants were included,with 1034 in the experimental group and 1007 in the control group.The Meta-analysis showed a significant effect of CEJ in treating leukopenia caused by tumor and immune diseases(three RCTs)[risk ratio(RR)=1.17,95%confidence interval(CI)(1.08,1.27),P=0.0002,I^(2)=35%].The combination of CEJ and Western Medicine showed superior results in terms of white blood cell(WBC)counts(fifteen RCTs)[mean difference(MD)=1.12,95%CI(0.83,1.42),P<0.00001,I^(2)=88%],Karnofsky Performance Status(KPS)levels(seven RCTs)[RR=1.39,95%CI(1.25,1.55),P<0.00001,I^(2)=36%],and mitigation of bone marrow toxicity(eleven RCTs)[RR=0.61,95%CI(0.54,0.69),P<0.00001,I^(2)=24%]compared to Western Medicine alone.Adverse events mainly included gastrointestinal and digestive reactions associated with chemotherapy drugs.CONCLUSION:CEJ alone or in combination with Western Medicine for treating leukopenia caused by tumor and immune diseases improved WBC counts,clinical efficacy,and quality of life.It also reduced bone marrow toxicity-induced leukopenia,enhanced the efficacy of chemotherapy while reducing its toxicity,and alleviated symptoms.No significant adverse events were reported in the RCTs,indicating favorable efficacy and safety.The Grading of Recommendations Assessment,Development and Evaluation assessment indicated a low level of evidence for CEJ in improving leukocyte elevation efficacy,KPS levels,and myelosuppressive toxicity.Therefore,large-scale,high-quality,rigorous multicenter double-blind controlled trials are recommended to strengthen the evidence level.
基金China Agriculture Research System of MOF and MARA(CARS-04)National Key Research and Development Program of China(Grant No.2022YFD2300904)the Key Scientific and Technological Project of Henan Province Department of China(Grant No.252102111171).
文摘In view of the existing composite planting cannot do independent control of fertilizer rate for each row,and fertilizer is easy to moisture solidification caking and rely on a single way to measure the speed of inaccurate problems,a split-drive variable fertilizer application system was designed for soybean and maize strip cropping composites.It includes roller crushing bi-directional spiral fertilizer discharger,split-drive variable fertilizer application system and‘GNSS+encoder’dual speed measurement system.By modeling agglomerated fertilizer particles,discrete element simulation was carried out to analyze the crushing effect.The speed measurement error variation folds of both GNSS and encoder under different speed conditions were obtained through field speed measurement tests.Finally,4.5 km/h was identified as the switching point between the two speed measurements.Through bench testing,a mathematical relationship model was developed for the soybean and maize belts in terms of‘Fertilizer Application Rate-Operating Travel Speed-Metering Mechanism Rotor Speed’,and the results are presented in the table below.Fertilizer discharge consistency was verified for fertilizer dischargers.Field trials were conducted,and the results show:The soybean belt had a maximum error of 4.81%at a fertilizer application rate of 150 kg/hm2 and an operating speed of 5 km/h;the maximum error in the corn belt was 4.67%at a fertilizer application rate of 600 kg/hm2 and operating speed of 4 km/h.Both have a maximum error of less than 5%,which meets the requirements for variable fertilizer application.
基金supported by the National Natural Science Foundation of China(Grant Nos.52072188,12122405,and 12274169)Program for Science and Technology Innovation Team in Zhejiang Province,China(Grant No.2021R01004)+2 种基金Natural Science Foundation of Zhejiang Province,China(Grant No.LQ24A040001)the Natural Science Foundation of Ningbo City,China(Grant No.2024J200)the Fundamental Research Funds for the Provincial Universities of Zhejiang(Grant No.SJLY2023003)。
文摘Achieving room-temperature superconductivity has been an enduring scientific quest,while hydrogen-rich compounds have emerged as highly promising candidates.Here,we systematically investigated the thermodynamic stability,crystal structure,electronic properties,and superconductivity within the ternary Y-Hf-H system under high pressure.Several distinct hydrides have been revealed,in which the hydrogen atoms are present in various hydrogenic motifs.A15-type hydride P_(m)3-YHfH_(6)with isolated H−is predicted to be dynamically stabilized down to 10GPa.The H atoms form pentagonal graphene-like layered-H10 anions in the Hf plane of P6-YHfH_(19),with aT_(c)of 95K at 100GPa.There are H cages in C_(mmm)-Y_(3)HfH_(24),and attributed to the robust electron–phonon coupling and high electronic density of states of hydrogen at the Fermi level,it demonstrates near-room temperature superconductivity with a T_(c)of 275K at 250GPa.Our work makes contributions to the understanding of the fundamental properties of ternary hydrides under high pressure and provides essential references for further research in this field.
基金Projects (50901017,50731002) supported by the National Natural Science Foundation of ChinaProject (20090042120008) supported by Doctoral Program Foundation of Institutions of Higher Education of ChinaProjects (N100702001,N090502002) supported by the Fundamental Research Funds of the Central Universities,China
文摘The phase equilibria and compositions in Mg-rich comer at 300℃ were determined in the Mg-Zn-A1 ternary system through the equilibrated alloy method by using X-ray diffraction （XRD） and scanning electron microscopy （SEM） assisted with energy dispersive spectroscopy of X-ray （EDS）. The results show that there exist three three-phase regions consisted of a-Mg＋Mg17A112（7）＋A15Mg11Zn4（φ）, a-Mg＋Mga2（Al, Zn）49（r）＋A15MgllZn4（φ） and a-Mg＋MgZn＋Mg32（A1, Zn）49（r）, respectively. The intermetallic compounds in equilibrium with a-Mg phase all have large composition ranges, not appear to be linear. At the same time, both zinc and aluminum are soluble in the a-Mg solid solution, with which the compounds are in equilibrium.
基金Project (50771027) supported by the National Natural Science Foundation of China
文摘The phase equilibria in Co-rich region of Co-Ti-Ta system were studied.The microstructure and XRD analysis together with EDS determination show that L12 type Co3Ti phase and Laves_C36_Co3Ta phase get equilibrium with α-Co phase from 1 000 to 1 200 ℃.The Co3Ti phase possesses a solubility of Ta higher than 10%,and the addition of Ta stabilizes the Co3Ti phase.The isothermal sections of the Co-Ti-Ta system in the Co-rich region at 1 000,1 100 and 1 200 ℃ were constructed according to the result.
基金Project(51071181)supported by the National Natural Science Foundation of ChinaProject(2013FJ4043)supported by the Natural Science Foundation of Hunan Province,China
文摘Taking AuCu3-type sublattice system as an example, three discoveries have been presented: First, the third barrier hindering the progress in metal materials science is that researchers have got used to recognizing experimental phenomena of alloy phase transitions during extremely slow variation in temperature by equilibrium thinking mode and then taking erroneous knowledge of experimental phenomena as selected information for establishing Gibbs energy function and so-called equilibrium phase diagram. Second, the equilibrium holographic network phase diagrams of AuCu3-type sublattice system may be used to describe systematic correlativity of the composition?temperature-dependent alloy gene arranging structures and complete thermodynamic properties, and to be a standard for studying experimental subequilibrium order-disorder transition. Third, the equilibrium transition of each alloy is a homogeneous single-phase rather than a heterogeneous two-phase, and there exists a single-phase boundary curve without two-phase region of the ordered and disordered phases; the composition and temperature of the top point on the phase-boundary curve are far away from the ones of the critical point of the AuCu3 compound.
基金Project(51071181)supported by the National Natural Science Foundation of ChinaProject(2013FJ4043)supported by the Natural Science Foundation of Hunan Province,China
文摘Taking Au3Cu-type sublattice system as an example, three discoveries have been presented. First, the fourth barrier to hinder the progress of metal materials science is that today’s researchers do not understand that the Gibbs energy function of an alloy phase should be derived from Gibbs energy partition function constructed of alloy gene sequence and their Gibbs energy sequence. Second, the six rules for establishing alloy gene Gibbs energy partition function have been discovered, and it has been specially proved that the probabilities of structure units occupied at the Gibbs energy levels in the degeneracy factor for calculating configuration entropy should be degenerated as ones of component atoms occupied at the lattice points. Third, the main characteristics unexpected by today’s researchers are as follows. There exists a single-phase boundary curve without two-phase region coexisting by the ordered and disordered phases. The composition and temperature of the top point on the phase-boundary curve are far away from those of the critical point of the Au3Cu compound; At 0 K, the composition of the lowest point on the composition-dependent Gibbs energy curve is notably deviated from that of the Au3Cu compounds. The theoretical limit composition range of long range ordered Au3Cu-type alloys is determined by the first jumping order degree.
基金Projects(50901017,51171043,51271053)supported by the National Natural Science Foundation of ChinaProject(20090042120008)supported by the Doctoral Program Foundation of Institutions of Higher Education of ChinaProject(2011BAE22B04-2)supported by National Key Technology R&D Program of China during the Twelfth Five-Year Plan Period
文摘The phase equilibria and compositions at the Mg-rich corner of the Mg?Zn?Al ternary system at 335 °C were systemically investigated through the equilibrated alloy method by using X-ray diffraction (XRD) and scanning electron microscopy (SEM) assisted with energy dispersive spectroscopy of X-ray (EDS). It is experimentally testified that theα-Mg solid solution is not in equilibrium with the Mg32(Al, Zn)49 (τ) ternary intermetallic compound orq quasicrystalline phase, but only in equilibrium with one ternary intermetallic compound Al5Mg11Zn4 (φ). The whole composition range of theφ phase was also obtained at 335 °C, i.e., 52.5%?56.4% Mg, 13.6%?24.0% Al, 19.6%?33.9% Zn (mole fraction). The solubility of Al in the MgZn phase is remarkably more than that in the Mg7Zn3 phase, and the maximum is about 8.6% Al. Aluminum and zinc are simultaneously soluble in theα-Mg solid solution.
文摘This paper analyzes the compound attractor structure of a new three-dimensional autonomous chaotic system. First, it is found that there exist five equilibria in the chaotic system, and the stabilities of these equilibria are discussed under a constant scalar control input parameter m. Secondly, the trajectories of the attractors on a y-z plane are examined, the reasons why these trajectories can exist or disappear are also described. Finally, the forming procedure of the different scrolls chaotic attractor is explored by computer simulations when the parameter m is varied. It is shown that the new chaotic attractor has a compound structure, it can evolve to other three-dimensional autonomous chaotic systems. The results of theoretical analysis and simulation are helpful for better understanding of other similar chaotic systems.
基金Supported by Beijing Municipal Student Research Training Program in Beijing ForestryUniversity(S201310022020)Fundamental Research Funds for the Central Universities(TD2011-14)~~
文摘[Objective]Preservation and waterproof treatment are two crucial parts in wood protection, which can not only extend the service time, but also expand the application range of wood products. [Method] This work combined CA with paraffin wax emulsion to treat wood samples, and basic properties of the compound system, such as stability （storage stability and centrifugal stability）, particle size and pH val-ue, and water repel ency （water absorption, shrinkage and swel ing） of treated sam-ples were investigated. [Result and Conclusion] 1） the compound systems of CA and paraffin latex had a favorable miscibility and stability; 2） compared with untreated wood, CA-treated samples showed poor water repel ing properties, whereas samples treated with the compound systems indicated an obvious reduction in water absorp-tion, and the shrinkage and swel ing of them were improved as wel .
文摘Multivariables, strong coupling, nonlinearity, and large delays characterize the boiler-turbine coordinated control systems for ship power equipment. To better deal with these conditions, a compound control strategy based on a support vector machine （SVM） with inverse identification was proposed and applied to research simulating coordinated control systems. This method combines SVM inverse control and fuzzy control, taking advantage of the merits of SVM inverse controls which can be designed easily and have high reliability, and those of fuzzy controls, which respond rapidly and have good anti-jamming capability and robustness. It ensures the controller can be controlled with near instantaneous adjustments to maintain a steady state, even if the SVM is not trained well. The simulation results show that the control quality of this fuzzy-SVM compound control algorithm is high, with good performance in dynamic response speed, static stability, restraint of overshoot, and robustness.
文摘The finding of the compound structure of a new four-scrolls chaotic system is reported, which is obtained by merging together two symmetrical attractors. And the two symmetrical attractors are generated only by adding a constant gain to the original system. Also, the forming procedure of the new four-scrolls chaotic attractor is explored and the relation between the constant gain and the properties of the system is given.
基金Project(50731002) supported by the National Natural Science Foundation of ChinaProject(20082030) supported by the Natural Science Foundation of Liaoning Province,China
文摘The phase equilibria and compositions in Mg-rich side at 300 ℃ were investigated in Mg-Zn-Ca ternary system through the equilibrated alloy method by using scanning electron microscopy,electron probe microanalysis,X-ray diffraction and transmission electron microscopy.The results show that two ternary compounds T1 and T2 can be in equilibrium with the Mg-based solid solution in Mg-Zn-Ca system.T1 phase is a linear compound with the composition region（molar fraction） of 15% Ca,20.5%-48.9% Zn and balanced Mg at 300 ℃.Its hexagonal structure parameters decrease with increasing Zn content,i.e.a=0.992-0.945 nm,c=1.034-1.003 nm.T2 phase has hexagonal structure with the composition region of 26.4%-28.4% Mg,63.2%-65.5% Zn and 7.1%-8.4% Ca.At 300 ℃,the solubility of Zn in the Mg-based solid solution increases for the addition of Ca,the maximum solubility of Zn is 3.7%.Three-phase fields consisting of--Mg＋Mg2Ca＋T1,--Mg＋T1＋T2,--Mg＋T2＋MgZn and MgZn＋T2＋Mg2Zn3 exist in the Mg-Zn-Ca system at 300 ℃.
文摘By analyzing the target's motion pattern, in terms of the requirement for the performance indexes of the follow up system, the structure changing control and time optimal theory is proposed. The system's control scheme from three different aspects(the dynamic response simulation, compound control simulation and dynamic tracking simulation) is also studied. And all the results proved the feasibility of the synthetical utilization of the open loop control, speed decreased control and position closed loop control.
