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Experimental and numerical study of hypervelocity impact damage on composite overwrapped pressure vessels
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作者 Yong-Pan Duan Run-Qiang Chi +1 位作者 Bao-Jun Pang Yuan Cai 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第1期58-72,共15页
Ground-based tests are important for studying hypervelocity impact(HVI)damage to spacecraft pressure vessels in the orbital debris environment.We analyzed the damage to composite overwrapped pressure vessels(COPVs)in ... Ground-based tests are important for studying hypervelocity impact(HVI)damage to spacecraft pressure vessels in the orbital debris environment.We analyzed the damage to composite overwrapped pressure vessels(COPVs)in the HVI tests and classified the damage into non-catastrophic damage and catastrophic damage.We proposed a numerical simulation method to further study non-catastrophic damage and revealed the characteristics and mechanisms of non-catastrophic damage affected by impact conditions and internal pressures.The fragments of the catastrophically damaged COPVs were collected after the tests.The crack distribution and propagation process of the catastrophic ruptures of the COPVs were analyzed.Our findings contribute to understanding the damage characteristics and mechanisms of COPVs by HVIs. 展开更多
关键词 Orbital debris Hypervelocity impact Composite overwrapped pressure vessels Damage mechanisms
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Three dimensional discrete element modelling of the conventional compression behavior of gas hydrate bearing coal
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作者 Xia Gao Nannan Wang +4 位作者 Baoyong Zhang Qiqi Lin Qiang Wu Wei Meng Xia Liu 《International Journal of Coal Science & Technology》 EI CAS CSCD 2024年第1期61-77,共17页
To analyze the relationship between macro and meso parameters of the gas hydrate bearing coal(GHBC)and to calibrate the meso-parameters,the numerical tests were conducted to simulate the laboratory triaxial compressio... To analyze the relationship between macro and meso parameters of the gas hydrate bearing coal(GHBC)and to calibrate the meso-parameters,the numerical tests were conducted to simulate the laboratory triaxial compression tests by PFC3D,with the parallel bond model employed as the particle contact constitutive model.First,twenty simulation tests were conducted to quantify the relationship between the macro–meso parameters.Then,nine orthogonal simulation tests were performed using four meso-mechanical parameters in a three-level to evaluate the sensitivity of the meso-mechanical parameters.Furthermore,the calibration method of the meso-parameters were then proposed.Finally,the contact force chain,the contact force and the contact number were examined to investigate the saturation effect on the meso-mechanical behavior of GHBC.The results show that:(1)The elastic modulus linearly increases with the bonding stiffness ratio and the friction coefficient while exponentially increasing with the normal bonding strength and the bonding radius coefficient.The failure strength increases exponentially with the increase of the friction coefficient,the normal bonding strength and the bonding radius coefficient,and remains constant with the increase of bond stiffness ratio;(2)The friction coefficient and the bond radius coefficient are most sensitive to the elastic modulus and the failure strength;(3)The number of the force chains,the contact force,and the bond strength between particles will increase with the increase of the hydrate saturation,which leads to the larger failure strength. 展开更多
关键词 Gas hydrate bearing coal Discrete element method Triaxial compression test Macro-meso mechanical propertie
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Quantitative geochemical reconstruction of Eocene paleoenvironment in Fushun Basin,northeast China
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作者 Yuanji Li Pingchang Sun +1 位作者 Qiang Zhang Junxian Wang 《Acta Geochimica》 EI CAS CSCD 2024年第3期571-587,共17页
The quantitative estimation of key parameters of paleotemperature and paleoprecipitation is crucial for paleoclimate reconstruction.Geochemical data from mod-ern sediments are highly consistent with climate data,and t... The quantitative estimation of key parameters of paleotemperature and paleoprecipitation is crucial for paleoclimate reconstruction.Geochemical data from mod-ern sediments are highly consistent with climate data,and their relationship can provide an important reference for the quantitative reconstruction of the paleoclimate.In this study,detailed inorganic geochemical analysis was carried out using high-precision sampling of the Paleogene(LFD-1 well)Guchengzi,Jijuntun and Xiloutian Formations in the Fushun Basin located in the mid-latitudes of the Northern Hemisphere.The Eocene Guchengzi Formation(54.51–47.8 Ma)and Jijuntun Formation(47.8–41.2 Ma)in the Fushun Basin were found to have been deposited under a humid climate.The lower(41.2–40.1 Ma)and upper(40.1–37.8 Ma)parts of the Xiloutian Formation were character-ized by semiarid and semihumid–semiarid climates,respec-tively,which is very similar to the paleoclimatic information reflected by organic carbon isotopes.The Eocene Thermal Maximum 2(ETM2,~53.7 Ma),Early Eocene Climatic Optimum(EECO,~53.1–46.5 Ma),Eocene Thermal Maxi-mum 3(ETM 3,~52.8 Ma),and Middle Eocene Climatic Optimum(MECO,~40.7–40.1 Ma)events significantly enhanced chemical weathering during these periods.The rapid increase in pCO_(2)concentration leads to an increase in temperature,precipitation,and surface runoff,exhibiting strong chemical weathering.The mean annual temperature(MATa)and mean annual precipitation(MAPa,MAPb,and MAPc)were estimated using parameters,such as the corrosion index without potassium(CIA-K),CaO/Al_(2)O_(3),and(Na_(2)O+K_(2)O)/Al_(2)O_(3).Comparing MAPa,MAPb,and MAPc with the MAP estimated using pollen data,MAPa and MAPb were found to be more sensitive to the climate during high precipitation periods(precipitation>1000 mm,Guchengzi Formation),and the recovered average precipi-tation was similar to MAP.In contrast,MAPc was more sensitive to the climate during low precipitation periods(precipitation<1000 mm,Jijuntun,and Xiloutian Forma-tions),with higher accuracy.To fully consider the influence of soluble inorganic salts Ca^(2+)and Na^(+),multivariate linear equations of CIA-K and CaO/Al_(2)O_(3)with CIA,and CIA-K and CaO/Al_(2)O_(3)with MAP were constructed,namely MAPd and MAPe.The results show that MAPe has the highest per-formance and can be effectively used to estimate the change of paleoprecipitation in Northeast Asia. 展开更多
关键词 EOCENE Fushun Basin Major element PALEOCLIMATE Geochemical reconstruction
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Effects of forced cooling on mechanical properties and fracture behavior of heavy section ductile iron 被引量:3
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作者 Er-jun Guo Liang Song +1 位作者 Li-ping Wang Dong-rong Liu 《China Foundry》 SCIE 2015年第6期398-405,共8页
To develop materials suitable for spent-nuclear-fuel containers, the effect of forced cooling on mechanical properties and fracture toughness of heavy section ductile iron was investigated. Two cubic castings with dif... To develop materials suitable for spent-nuclear-fuel containers, the effect of forced cooling on mechanical properties and fracture toughness of heavy section ductile iron was investigated. Two cubic castings with different cooling processes were prepared: casting A was prepared in a totally sand mold, and casting B was prepared in a sand mold with two chilling blocks placed on the left and right sides of the mold. Three positions in each casting with different solidification cooling rates were chosen. In-situ SEM tensile experiment was used to observe the dynamic tensile process. Fracture analysis was conducted to study the influence of vermicular and slightly irregular spheroidal graphite on the fracture behavior of heavy section ductile iron. Results show that the tensile strength, elongation, impact toughness and fracture toughness at different positions of the two castings all decrease with decreasing cooling rate. With the increase of solidification time, the fracture mechanism of conventional casting A changes from ductile fracture to brittle fracture, and that of casting B with forced cooling changes from ductile fracture to a mixture of ductile-brittle fracture. 展开更多
关键词 heavy section ductile iron forced cooling in-situ SEM tensile fracture toughness
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Influence of rolling directions on microstructure,mechanical properties and anisotropy of Mg-5Li-1Al-0.5Y alloy 被引量:2
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作者 Tianzi Wang Tianlong Zhu +2 位作者 Jianfeng Sun Ruizhi Wu Milin Zhang 《Journal of Magnesium and Alloys》 SCIE EI CAS 2015年第4期345-351,共7页
Mg-5Li-1Al-0.5Y alloy was rolled with different directions.The microstructure,mechanical properties and texture of the specimens were investigated with optical microscope,tensile tester and X-ray diffraction.The resul... Mg-5Li-1Al-0.5Y alloy was rolled with different directions.The microstructure,mechanical properties and texture of the specimens were investigated with optical microscope,tensile tester and X-ray diffraction.The results show that changing rolling directions can refine the grain size of as-rolled alloys.Meanwhile,rolling directions have an obvious influence on the mechanical properties and texture of Mg-5Li-1Al-0.5Y alloy,thus affecting the anisotropy of the alloy.The sheet,of which the RD(rolling direction)and ND(normal direction)are both changed between two passes,possesses the smallest anisotropy.From the texture results,changing rolling directions reduces the maximum pole density,making the highest point distribution region excursion and the highest point distributes more scatteredly. 展开更多
关键词 Mg-Li alloy Rolling directions MICROSTRUCTURE Mechanical property ANISOTROPY
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Effect of Gd on microstructure and refinement performance of Al-5Ti-B alloy 被引量:2
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作者 Dong-song Yin Ning Zhang +1 位作者 Ke-ju Chen Yun-long Zhang 《China Foundry》 SCIE CAS 2021年第3期223-228,共6页
Al-5Ti-B and Al-5Ti-B-Gd master alloy refiners were fabricated by fluorine salt casting method.The microstructure and phase constitution of the master alloys were investigated by scanning electron microscopy (SEM),tra... Al-5Ti-B and Al-5Ti-B-Gd master alloy refiners were fabricated by fluorine salt casting method.The microstructure and phase constitution of the master alloys were investigated by scanning electron microscopy (SEM),transmission electron microscopy (TEM) and X-ray diffraction (XRD).The results show that Al-Ti-B alloy refiner consists of Al_(3)Ti phase and TiB2 phase.After Gd is introduced into the intermediate alloy,Ti_(2)Al_(20)Gd phase appears in the alloy,the size of Al_(3)Ti is significantly reduced,and Ti-Al-Gd phase is found in the edge of Al_(3)Ti phase.At the same time,some independent Ti-Al-Gd phases appear in local areas,which are Ti_(2)Al_(20)Gd phase determined by micro-area electron diffraction analysis.Analysis and calculation results of the high-resolution images of the Ti_(2)Al_(20)Gd/Al structure show that there is no other compound at the junction between the Ti_(2)Al_(20)Gd phase and Al,and Ti_(2)Al_(20)Gd phase has a great difference in atomic space with the α-Al,which cannot be directly used as heterogeneous nucleus.But,after being decomposed in the aluminum melt,the Ti_(2)Al_(20)Gd phase can promote the refinement effect of the refiner.In the Al-Ti-B-Gd master alloy,there are many dispersed Al_(3)Ti particles with a size of less than 1 μm,which can promote the Al-5Ti-B refining effect. 展开更多
关键词 Al-5Ti-B alloy refiner Al_(3)Ti rare earth Gd Ti_(2)Al_(20)Gd
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Upper Bound Solution of Soil Slope Stability under Coupling Effect of Rainfall and Earthquake 被引量:1
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作者 YIN Xiaojun WANG Lanmin 《Journal of Donghua University(English Edition)》 EI CAS 2019年第4期357-363,共7页
Based on the limit analysis upper bound method,a new model of soil slope collapse has been proposed which consists of two rigid block zones and a plastic shear zone.Soil slope was induced failure by coupling effect of... Based on the limit analysis upper bound method,a new model of soil slope collapse has been proposed which consists of two rigid block zones and a plastic shear zone.Soil slope was induced failure by coupling effect of rainfall and earthquake,and these blocks were also incorporated horizontal earthquake force and vertical gravitate.The velocities and forces were analyzed in three blocks,and the expression of velocity discontinuities was obtained by the principle of incompressibility.The external force work for the blocks,the internal energy of the plastic shear zone and the velocity discontinuous were solved.The present stability ratios are compared to the prevenient research,which shows the superiority of the mechanism and rationality of the analysis.The critical height of the soil slope can provide theoretical basis for slope support and design. 展开更多
关键词 soil slope coupling effect upper BOUND SOLUTION STABILITY ratio EARTHQUAKE RAINFALL
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Acoustic emission characteristics and stress release rate of coal samples in different dynamic destruction time 被引量:3
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作者 Xiao Fukun Liu Gang +3 位作者 Zhang Ze Shen Zhiliang Zhang Fengrui Wang Yifei 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2016年第6期981-988,共8页
Considering the importance of the prediction of rock burst disasters, and in order to grasp the law of acoustic emission(AE) of coal samples in different dynamic destruction time, the SH-II AE monitoring system was ad... Considering the importance of the prediction of rock burst disasters, and in order to grasp the law of acoustic emission(AE) of coal samples in different dynamic destruction time, the SH-II AE monitoring system was adopted to monitor the failure process of coal samples. The study of the change rule of the AE numbers, energy, ‘b' value and spectrum in the micro crack propagation process of the coal samples shows that as dynamic damage time went by, AE presented high-energy counts and the accumulated counts increased during the compression phase. The AE energy and cumulative counts increased during the elastic stage. The AE blank area increased gradually and the blank lines were more and more obvious in the molding stage. The AE counts and energy showed a trend of decrease in the residual damage phase.AE ‘b' values gradually became sparse, and the large scale cracks percentage compared with micro cracks decreased and the degree of damage decreased. The AE frequency spectrum peak went from the residual damage phase to the molding phase, and finally it was nearly stable, besides the bandwidth of the main frequency is gradually narrowed. Also, the frequency peak changed from single peak frequency to bi-peak frequency and to the single peak frequency. Uniaxial compressive strength is more sensitive than the elastic modulus to dynamic damage time. 展开更多
关键词 Dynamic destruction time Acoustic emission Outburst-proneness Stress release rate
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Flocculating Properties and Production of the Compound Bioflocculant by Rhizobium Radiobacter F2 and Bacillus Sphaeicus F6 被引量:1
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作者 Lixin Li Lingyan Feng +1 位作者 Fang Ma Qianshen Zhao 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2015年第4期20-26,共7页
A compound bioflocculant CBF,produced by mixed culture of Rhizobium radiobacter F2 and Bacillus sphaeicus F6, was investigated with regard to its production and flocculating properties. The optimization of the culture... A compound bioflocculant CBF,produced by mixed culture of Rhizobium radiobacter F2 and Bacillus sphaeicus F6, was investigated with regard to its production and flocculating properties. The optimization of the culture medium constituents including carbon source,nitrogen source and C / N ratio,metal ions and ionic strength on CBF production were studied. Flocculating properties of CBF were examined by a series of experiments and CBF had good flocculating activities in kaolin suspension with divalent cations and stable over wide range of p H. Studies of the flocculating properties revealed that the flocculation could be stimulated by cations Ca2+,Mg2+,Fe2+,Al3+and Fe3+. In addition,it was stable at 4-30 ℃ in the presence of Ca Cl2. It was found to be effective for flocculation of a kaolin suspension under neutral and weak alkaline conditions( p H 7. 0- 9. 0),and flocculating activities of higher than 95% were obtained when the CBF concentrations among 6- 14 mg / L at p H 8. 0. The results of this study indicate that CBF is a potential replacement of conventional synthetic flocculants and is widely applied in water treatment and downstream processing of food and fermentation industries. 展开更多
关键词 compound bioflocculant Rhizobium radiobacter Bacillus sphaeicus PRODUCTION flocculating activity
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Haze Control by Industrialization:A Win-win Mode of Ecological Civilization and Economic Development 被引量:1
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作者 Yan HAN Qingyu CHAI +5 位作者 Lei WANG Yunlong YAO Yunna JIA Jiahui SHAO Hongxian YU Fangying CHAI 《Asian Agricultural Research》 2017年第2期66-71,共6页
Haze control is a difficult and arduous battle,and it is a major decision concerning the people's livelihood and national ecological civilization construction.Taking Heilongjiang Province as an example,this paper ... Haze control is a difficult and arduous battle,and it is a major decision concerning the people's livelihood and national ecological civilization construction.Taking Heilongjiang Province as an example,this paper introduced a new idea for haze control.Haze in Heilongjiang Province was mainly resulted from straw burning.Market-oriented,large-scale,and industrialized haze control relying on science and technology is new opportunity and challenge for realizing ecological civilization and revitalizing the economy of Heilongjiang Province. 展开更多
关键词 HAZE CONTROL INDUSTRIALIZATION
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U-Pb dating and geochemistry of granite porphyry dykes in the Xicha gold-(silver)deposit,southern Jilin Province,China,and their metallogenic significance
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作者 Jian Wang Fengyue Sun +1 位作者 Bile Li Lihui Tian 《Acta Geochimica》 EI CAS CSCD 2020年第4期574-586,共13页
We report U-Pb dating of zircon,as well as geochemical and Hf isotope data,in order to constrain the formation time,magma source,and tectonic setting of granite porphyry dykes in the Xicha gold-(silver)district in sou... We report U-Pb dating of zircon,as well as geochemical and Hf isotope data,in order to constrain the formation time,magma source,and tectonic setting of granite porphyry dykes in the Xicha gold-(silver)district in southern Jilin Province,Northeast China.The zircon grains are euhedral-subhedral,display oscillatory growth zoning and have Th/U ratios varying between 0.11 and 0.78,which together imply a magmatic origin.The dating results indicate the porphyry formed in the Early Cretaceous(122±1 Ma)and it contains SiO2=70.64-72.31 wt%,Al2O3-=13.99-14.64 wt%,K2O+Na2O=6.96-7.81 wt%K2O/Na2O=1.24-2.10,and A/CNK=1.11-1.41.Chemically,the porphyry belongs to a high-K calc-alkaline S-type granite.Chondrite-normalized rare earth elements(REE)patterns show LREE enrichment,light rare earth elements(LREE)/heavy rare earth elements(HREE)=9.93-11.97(La/Yb)N=11.08-15.16,and d Eu=0.69-0.95.On the trace element spider diagram,large ion lithophile elements such as Rb,Ba,K,Th,and U are enriched,whereas the high field strength elements Ti and P are depleted.The e Hf(t)values of zircon from the granite porphyry vary between-17.1 and-13.2,and their Hf two-stage model ages vary from 2.01 to 2.26 Ga,implying that the magma was derived from partial melting of old lower crust.The granite porphyry dykes and many A-type granites in the region formed at the same time,suggesting an extensiona environment.The combination of the occurrence of strong magmatism,large-scale mineralization,and extensiona tectonics throughout much of Eastern China indicate that the Early Cretaceous was a period of significant lithospheric thinning.The southern Jilin Province,therefore,experienced lithospheric thinning during the Early Cretaceous. 展开更多
关键词 Southern Jilin Province Syn-mineralization dykes Jinchanggou Zircon U-Pb geochronology GEOCHEMISTRY Hf isotopes
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Synthesis and electrical properties of In_2O_3(ZnO)_m superlattice nanobelt
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作者 唐欣月 高红 +4 位作者 武立立 温静 潘思明 刘欣 张喜田 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第2期394-398,共5页
One-dimensional(ID) In2O3(ZnO)m superlattice nanobelts are synthesized by a chemical vapor deposition method.The formation of the In2O3(ZnO)m superlattice is verified by the high-resolution transmission electron... One-dimensional(ID) In2O3(ZnO)m superlattice nanobelts are synthesized by a chemical vapor deposition method.The formation of the In2O3(ZnO)m superlattice is verified by the high-resolution transmission electron microscopy images.The typical zigzag boundaries could be clearly observed.An additional peak at 614 cm^-1 is found in the Raman spectrum,which may correspond to the superlattice structure.The study about the electrical transport properties reveals that the In2O3(ZnO)m nanobelts exhibit peculiar nonlinear I-V characteristics even under the Ohmic contact measurement condition,which are different from the Ohmic behaviors of the In-doped ZnO nanobelts.The photoelectrical measurements show the differences in the photocurrent property between them,and their transport mechanisms are also discussed. 展开更多
关键词 In2O3(ZnO)m SUPERLATTICE electrical properties
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An Affective EEG Analysis Method Without Feature Engineering
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作者 Jian Zhang Chunying Fang +1 位作者 Yanghao Wu Mingjie Chang 《Journal of Electronic Research and Application》 2024年第1期36-45,共10页
Emotional electroencephalography(EEG)signals are a primary means of recording emotional brain activity.Currently,the most effective methods for analyzing emotional EEG signals involve feature engineering and neural ne... Emotional electroencephalography(EEG)signals are a primary means of recording emotional brain activity.Currently,the most effective methods for analyzing emotional EEG signals involve feature engineering and neural networks.However,neural networks possess a strong ability for automatic feature extraction.Is it possible to discard feature engineering and directly employ neural networks for end-to-end recognition?Based on the characteristics of EEG signals,this paper proposes an end-to-end feature extraction and classification method for a dynamic self-attention network(DySAT).The study reveals significant differences in brain activity patterns associated with different emotions across various experimenters and time periods.The results of this experiment can provide insights into the reasons behind these differences. 展开更多
关键词 Dynamic graph classification Self-attention mechanism Dynamic self-attention network SEED dataset
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Improved H_∞ control for networked control systems with network-induced delay and packet dropout 被引量:8
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作者 李冰 武俊峰 黄玲 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第5期1215-1223,共9页
The H_∞ performance analysis and controller design for linear networked control systems(NCSs) are presented.The NCSs are considered a linear continuous system with time-varying interval input delay by assuming that t... The H_∞ performance analysis and controller design for linear networked control systems(NCSs) are presented.The NCSs are considered a linear continuous system with time-varying interval input delay by assuming that the sensor is time-driven and the logic Zero-order-holder(ZOH) and controller are event-driven.Based on this model,the delay interval is divided into two equal subintervals for H_∞ performance analysis.An improved H_∞ stabilization condition is obtained in linear matrix inequalities(LMIs) framework by adequately considering the information about the bounds of the input delay to construct novel Lyapunov–Krasovskii functionals(LKFs).For the purpose of reducing the conservatism of the proposed results,the bounds of the LKFs differential cross terms are properly estimated without introducing any slack matrix variables.Moreover,the H_∞ controller is reasonably designed to guarantee the robust asymptotic stability for the linear NCSs with an H_∞ performance level γ.Numerical simulation examples are included to validate the reduced conservatism and effectiveness of our proposed method. 展开更多
关键词 H performance networked control systems packet dropout network-induced delay
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Synthesis of TiO_2/g-C_3N_4 nanocomposites with phosphate–oxygen functional bridges for improved photocatalytic activity 被引量:7
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作者 Chong Liu Fazal Raziq +3 位作者 Zhijun Li Yang Qu Amir Zada Liqiang Jing 《Chinese Journal of Catalysis》 CSCD 北大核心 2017年第6期1072-1078,共7页
One of the most general methods to enhance the separation of photogenerated carriers for g‐C3N4is to construct a suitable heterojunctional composite,according to the principle of matching energy levels.The interface ... One of the most general methods to enhance the separation of photogenerated carriers for g‐C3N4is to construct a suitable heterojunctional composite,according to the principle of matching energy levels.The interface contact in the fabricated nanocomposite greatly influences the charge transfer and separation so as to determine the final photocatalytic activities.However,the role of interface contact is often neglected,and is rarely reported to date.Hence,it is possible to further enhance the photocatalytic activity of g‐C3N4‐based nanocomposite by improving the interfacial connection.Herein,phosphate-oxygen(P-O)bridged TiO2/g‐C3N4nanocomposites were successfully synthesized using a simple wet chemical method,and the effects of the P-O functional bridges on the photogenerated charge separation and photocatalytic activity for pollutant degradation and CO2reduction were investigated.The photocatalytic activity of g‐C3N4was greatly improved upon coupling with an appropriate amount of nanocrystalline TiO2,especially with P-O bridged TiO2.Atmosphere‐controlled steady‐state surface photovoltage spectroscopy and photoluminescence spectroscopy analyses revealed clearly the enhancement of photogenerated charge separation of g‐C3N4upon coupling with the P-O bridged TiO2,resulting from the built P-O bridges between TiO2and g‐C3N4so as to promote effective transfer of excited electrons from g‐C3N4to TiO2.This enhancement was responsible for the improved photoactivity of the P-O bridged TiO2/g‐C3N4nanocomposite,which exhibited three‐time photocatalytic activity enhancement for2,4‐dichlorophenol degradation and CO2reduction compared with bare g‐C3N4.Furthermore,radical‐trapping experiments revealed that the·OH species formed as hole‐modulated direct intermediates dominated the photocatalytic degradation of2,4‐dichlorophenol.This work provides a feasible strategy for the design and synthesis of high‐performance g‐C3N4‐based nanocomposite photocatalysts for pollutant degradation and CO2reduction. 展开更多
关键词 TiO2/graphitic carbon nitride NANOCOMPOSITE Phosphate–oxygen bridge Charge transfer and separation PHOTOCATALYSIS Carbon dioxide conversion
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Influencing factors for catalytic oxidation of mine gas to methanol in liquid phase 被引量:2
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作者 ZHU Lihua XU Feng +1 位作者 BI Yewu SHEN Bin 《Chinese Journal Of Geochemistry》 EI CAS CSCD 2014年第2期183-186,共4页
The influencing factors for liquid phase catalytic oxidation of mine gas to methanol(in form of CH3COOCH3) are studied using the self-established experimental apparatus. The results show that CH3COOCH3(target product)... The influencing factors for liquid phase catalytic oxidation of mine gas to methanol(in form of CH3COOCH3) are studied using the self-established experimental apparatus. The results show that CH3COOCH3(target product) is obtained by using CH3COOH as reaction solvent, and the yield of target product increases with the increasing of reaction temperature, gas pressure and reaction time. In the mine gas-Pd(OAc)2-CH3COOH system, the yield of CH3COOCH3 increases with the increasing of addition of Pd(OAc)2 which is redox catalyst for mine gas conversion. The yield of CH3COOCH3 will be greatly improved by composite additional oxidant which is obtained by equimolar mix of p-benzoquinone with NO2. 展开更多
关键词 液相催化氧化 矿井瓦斯 影响因素 甲醇 还原催化剂 实验装置 反应溶剂 反应温度
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Long-Term Bending Behaviour of Prestressed Glulam Bamboo-Wood Beam Based on Creep Effect 被引量:4
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作者 Nan Guo Huajing Xiong +4 位作者 Mingtao Wu Hongliang Zuo Fengguo Jiang Xiaofeng Hou Dabo Xin 《Structural Durability & Health Monitoring》 EI 2020年第3期229-248,共20页
Creep is an important characteristic of bamboo and wood materials under long-term loading.This paper aims to study the long-term bending beha-viour of prestressed glulam bamboo-wood beam(GBWB).For this,14 pre-stressed... Creep is an important characteristic of bamboo and wood materials under long-term loading.This paper aims to study the long-term bending beha-viour of prestressed glulam bamboo-wood beam(GBWB).For this,14 pre-stressed GBWBs were selected and subjected to a long-term loading test for 60 days.Then,a comparative analysis was performed for the effects of pre-tension values,the number of pre-stressed wires,and long-term load on the stress variation of the steel wire and the long-term deflection of the beam midspan.The test results showed that with the number of prestressed wires increasing,the total stress of the steel wire in the beam midspan and the ratio of the long-term deflec-tion to the total deflection decreases decreased,but when the number of steel wires exceeded 4,the total stress and long-term deflection was less infuenced;with the pre-tension value increasing,the ratio of the total stress of the steel wire in the beam midspan and the ratio of the long-temm deflection to the total deflec-tion also decreased,but when the prestress force was greater than 3.975 kN,the:total stress and long-term deflection were less affected;with the other parameters unchanged,when the value of the long-term load increased,the total stress of the steel wire decreased,and the long-temm deflection of the beam midspan increased,which shall be more significant with the long-term load greater than 30%of the standard ultimate bearing capacity.After the test,the experimental data were fitted,and the creep coefficient was given.Finally,the long-term stiffness calcula-tion fommula of the pre-stressed GBWB based on creep effect was proposed.The research findings have certain theoretical significance and engineering value. 展开更多
关键词 Prestressed glulam bamboo-wood beam long-temn loading test steel wire stress long-term deflection creep cofficient
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Ultrasonic vibrations and coal permeability: Laboratory experimental investigations and numerical simulations 被引量:11
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作者 Zhang Junwen Li Yulin 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2017年第2期221-228,共8页
Ultrasonic vibrations in coal lead to cavitation bubble oscillation, growth, shrinkage, and collapse, and the strong vibration of cavitation bubbles not only makes coal pores break and cracks propagate, but plays an i... Ultrasonic vibrations in coal lead to cavitation bubble oscillation, growth, shrinkage, and collapse, and the strong vibration of cavitation bubbles not only makes coal pores break and cracks propagate, but plays an important role in enhancing the permeability of coal. In this paper, the influence of ultrasonic cavitation on coal and the effects of the sonic waves on crack generation, propagation, connection, as well as the effect of cracks on the coal permeability, are studied. The experimental results show that cracks in coal are generated even connected rapidly after ultrasonic cavitation. Under the effect of ultrasonic cavitation,the permeability increases between 30% and 60%, and the number of cracks in coal also significantly increased. Numerical experiments show that the effective sound pressure is beneficial to fracture propagation and connection, and it is closely related to the permeability. Moreover, the numerical simulations and physical experiments provide a guide for the coal permeability improvement. 展开更多
关键词 Ultrasonic cavitation Rock-coal Coal fracture Permeability Experimental analysis
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UPA based 3D visualization of discontinuities in great thickness EBW seam 被引量:2
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作者 Sun Changli Gang Tie Chi Dazhao 《China Welding》 EI CAS 2016年第2期1-5,共5页
Electron beam welding (EBW) is a fusion welding process in which a beam of high-velocity electrons is applied to two materials to be joined. It is a complex high-temperature metallurgical process, and the quality of... Electron beam welding (EBW) is a fusion welding process in which a beam of high-velocity electrons is applied to two materials to be joined. It is a complex high-temperature metallurgical process, and the quality of welding may deteriorate because of defects caused by improper welding parameters, especially in the EBW of thickened aluminum alloy plate. Ultrasonic phased array(UPA) technology has been applied more widely in the field of nondestructive testing because of its ability of effectively controlling the shape and direction of the emitted ultrasonic beam. In present research, a specimen with EBW seam on thickened aluminum plate was tested with a linear array ultrasonic phased array probe, and a large number of B-scan images of the weld were acquired by electronic scanning in probe combined with the mechanical scanning of the probe along the weld direction. This large number of B-scan images were stacked to construct the volume data, with which the 3D image of the weld discontinuities were reconstructed, and the 3D visualization was realized. More details about weld discontinuities' spatial distribution and orientation were revealed, and this approach also made the results of non-destructive ultrasonic testing more easily to understand. 展开更多
关键词 electron beam welding thickened aluminum plate ultrasonic phased array 3D reconstruction 3Dvisualization
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Latest Zircon U-Pb Age of the Baiyingaolao Formation Volcanic Rocks in the Keyihe Area of North-Central Da Hinggan Mountains 被引量:1
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作者 WANG Chunyu SUN Deyou +2 位作者 TIAN Lihui BU Jun SHANG Yuhang 《Acta Geologica Sinica(English Edition)》 CAS CSCD 2018年第5期2034-2035,共2页
Objective Mesozoic volcanic rocks are mainly distributed in the Da Hinggan Mountains.The Baiyingaolao Formation is the main stratum in this area and has been considered to be formed in the Late Jurassic.Many scholars ... Objective Mesozoic volcanic rocks are mainly distributed in the Da Hinggan Mountains.The Baiyingaolao Formation is the main stratum in this area and has been considered to be formed in the Late Jurassic.Many scholars have researched these Mesozoic volcanic rocks in this area,which have been much debatable(Zhang Xiangxin et al.,2017).A series of studies focusing on the Baiyingaolao Formation volcanic rocks in the middle-south section of 展开更多
关键词 PB ICP MS Latest Zircon U-Pb Age of the Baiyingaolao Formation Volcanic Rocks in the Keyihe Area of North-Central Da Hinggan Mountains
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