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17篇 您的检索式:作者名="Dazhao Li"
    题名 作者 年代 出处 被引量
1Numerical simulation of RCS for carrier electronic warfare airplanes显示文摘This paper studies the radar cross section(RCS) of carrier electronic warfare airplanes.Under the typical naval operations section, the mathematical model of the radar wave's pitch angle incidence range analysis is established. Based on the CATIA software, considering dynamic deflections of duck wing leading edge flaps, flaperons, horizontal tail, and rudder, as well as aircraft with air-to-air missile, anti-radiation missile, electronic jamming pod, and other weapons, the 3D models of carrier electronic warfare airplanes Model A and Model B with weapons were established. Based on the physical optics method and the equivalent electromagnetic flow method, by the use of the RCSAnsys software, the characteristics of carrier electronic warfare airplanes' RCS under steady and dynamic flights were simulated under the UHF, X, and S radar bands. This paper researches the detection probability of aircraft by radars under the condition of electronic warfare, and completes the mathematical statistical analysis of the simulation results. The results show that: The Model A of carrier electronic warfare airplane is better than Model B on stealth performance and on discover probability by radar detection effectively.Yue Kuizhi Liu Wenlin Li Guanxiong Ji Jinzu Yu Dazhao 2015Chinese Journal of Aeronautics2015,28,2:22
2Rock burst prevention based on dissipative structure theory显示文摘Dynamic collapses of deeply mined coal rocks are severe.In order to explore new ideas for rock burst prevention,the relationship between entropy equations and dissipative structure was studied,and a concept-rock burst activity system(RAS) was proposed and its entropy was analyzed.The energy features of RAS were analyzed,and the relationship between electromagnetic radiation(EMR) intensity E and dissipated energy Ud was initially established.We suggest that rock burst normally happens only when diS deS in RAS;RAS is the dissipative structure before collapse,and after which it become a new orderly structure,i.e.,a ''dead'',a statically orderly structure.We advanced that the effective way to prevent rock burst is to introduce entropy to the system for it keeps the system away from the dissipative structure.E and Ud of RAS are positively related,which is used as a bridge between dissipative structure theory and rock burst prevention engineering applications.Based on this,and using the data of rock burst prevention for working face No.250205up of Yanbei coal mine,an engineering verification for the dissipative structure of RAS was carried out,which showed good results.Song Dazhao Wang Enyuan Li Nan Jin Mingyue Xue Shipeng 2012International Journal of Mining Science and Technology2012,22,2:17
3Energy dissipation of coal and rock during damage and failure process based on EMR显示文摘The physical and mechanical change processes of coal and rock are closely related to energy transformation,and the destruction and failure of coal and rock is an instability phenomena driven by energy change.However,the energy change of large-scale coal rock in the mine site is hardly calculated accurately,making it difficult to monitor coal-rock systematic failure and collapse from the perspective of energy.By the energy dissipation EMR monitoring system,we studied the damage and failure of coal and rock with bursting liability from the energy dissipation point using the geophysical method-EMR,and explored the energy dissipation characteristics during uniaxial compression and their main influencing factors.The results show that under displacement-control loading mode,there are 2 types of energy dissipation trends for both coal and rock with bursting liability.The type Ⅰ trend is a steady increase one during the whole process,therein,the energy dissipation of rock samples is accelerated at the peak load.The type Ⅱ trend energy is a W-shaped fluctuating one containing 6 stages.Under load-control loading mode,there is one energy dissipation trend of shock downward-steady rise.Besides that,rock samples also present a trend of 4 stages.The energy dissipation characteristics of coal and rockduring loading failure process can be used as effective criteria to assess whether they are in a stable or destructive stage.The factors influencing energy dissipation in the loading failure process of coal and rock mainly include strength,homogeneity,and energy input efficiency.Song Dazhao Wang Enyuan Li Zhonghui Liu Jie Xu Wenquan 2015International Journal of Mining Science and Technology2015,25,5:16
4Conceptual design and RCS performance research of shipborne early warning aircraft显示文摘In order to improve the survivability of the aircraft,conceptual design and radar cross section(RCS) performance research are done. The CATIA software is used to design the 3D digital model of the shipborne early warning aircraft, and some measures are taken to reduce the RCS characteristics of the early warning aircraft at the same time. Based on the physical optics method and the equivalent electromagnetic flow method,the aircraft's RCS characteristics and strength distribution characteristics are simulated numerically, and compared with the foreign advanced shipborne early warning aircraft. The simulation results show that under the X radar band, when the incident wave pitching angle is 0?, compared with the foreign advanced shipborne early warning aircraft, the forward RCS average value of the conceptual shipborne early warning aircraft is reduced to 24.49%, the lateral RCS average value is reduced to 5.04%, and the backward RCS average value is reduced to 39.26%. The research results of this paper are expected to provide theoretical basis and technical support for the conceptual design and the stealth design of the shipborne early warning aircraft.Kuizhi Yue Yong Gao Guanxiong Li Dazhao Yu 2014Journal of Systems Engineering and Electronics2014,25,6:6
5Experimental study on the infrared precursor characteristics of gas-bearing coal failure under loading显示文摘The stress and gas pressure in deep coal seams are very high,and instability and failure rapidly and intensely occur.It is important to study the infrared precursor characteristics of gas-bearing coal instability and failure.In this paper,a self-developed stress-gas coupling failure infrared experimental system was used to analyse the infrared radiation temperature(IRT)and infrared thermal image precursor characteristics of gas-free coal and gas-bearing coal.The changes in the areas of the infrared temperature anomalous precursor regions and the effect of the gas on the infrared precursors were examined.The results show that high-temperature anomalous precursors arise mainly when the gas-free coal fails under loading,whereas the gas-bearing coal has high-temperature and low-temperature anomalous precursors.The area of the high-temperature anomalous precursor is approximately 30%–40%under gasbearing coal unstable failure,which is lower than the 60%–70%of the gas-free coal.The area of the low-temperature abnormal precursor is approximately 3%–6%,which is higher than the 1%–2%of the gas-free coal.With increasing gas pressure,the area of the high-temperature anomalous precursor gradually decreases,and the area of the low-temperature anomalous precursor gradually increases.The highand low-temperature anomalous precursors of gas-bearing coal are mainly caused by gas desorption,volume expansion,and thermal friction.The presence of gas inhibits the increase in IRT on the coal surface and increases the difficulty of infrared radiation(IR)monitoring and early warning for gas-bearing coal.Shan Yin Zhonghui Li Dazhao Song Xueqiu He Liming Qiu Quan Lou He Tian 2021International Journal of Mining Science and Technology2021,31,5:4
6Hot deformation behavior of Fe–27.34Mn–8.63Al–1.03C lightweight steel显示文摘Hot compression tests were performed to investigate the hot deformation behavior of Fe–27.34Mn–8.63Al–1.03C lightweight steel and optimize the hot workability parameters. The temperature range was 900–1150℃ and the strain rate range was 0.01–5 s^(-1)on a Gleeble-3800 thermal simulator machine. The results showed that the flow stress increased with decreasing deformation temperature and increasing strain rate. According to the constitutive equation, the activation energy of hot deformation was 422.88 kJ·mol^(-1). The relationship between the critical stress and peak stress of the tested steel was established, and a dynamic recrystallization kinetic model was thus obtained. Based on this model, the effects of strain rate and deformation temperature on the volume fraction of dynamically recrystallized grains were explored. The microstructural examination and processing map results revealed that the tested steel exhibited a good hot workability at deformation temperatures of 1010–1100℃ and strain rate of 0.01 s^(-1).Haitao Lu Dazhao Li Siyuan Li Yong’an Chen 2023International Journal of Minerals,Metallurgy and Materials2023,30,4:2
7Hot Deformation Behavior of Low Carbon Steel during Compression at Elevated Temperature显示文摘Hot compression tests of low carbon steel were carried out on Gleeble-3500 system in the temperature range from 750 to 900 ℃ and in the strain rate range from 0.001 to 1.0 s-1, and the associated microstructural evolution was studied by observations with a metallographic microscope. The results show that the stress-strain curves exhibit a peak stress at critical strain, after which the fl ow stresses decrease monotonically until reaching high strains, showing a dynamic fl ow softening. The peak stress level decreases with increasing deformation temperature and decreasing strain rate, which can be represented by the Zener-Hollomon parameter Z in the hyperbolic sine equation. The fl ow stress increases with increasing strain rate and decreasing deforming temperature. The fl ow stress can be described by constitutive equation in hyperbolic sine function and can also be described by a Zener–Hollomon parameter Z. With increasing deformation temperature and decreasing strain rate, the grain size as well as the volume fraction of the recrystallized grains increase. The safe region for hot working of the alloy has been determined according to the processing map and microstructure at the true strain of 0.5, which is the deformation temperature of 840-940 ℃ and the strain rate of 0.001-1.0 s-1.刘和平 LIU Bin LI Dazhao SUN Hu'er SUN Feng'er JIN Xuejun ZHANG Yongtao 2014Journal of Wuhan University of Technology(Materials Science)2014,29,3:2
8A dynamic ejection coal burst model for coalmine roadway collapse显示文摘In this study,we established a dynamic ejection coal burst model for a coalmine roadway subject to stress,and held that the stress concentration zone at the roadway side is the direct energy source of this ejection.The formation and development of such burst undergoes three stages:(1)instability and propagation of the cracks in the stress concentration zone,(2)emerging of a layered energy storage structure in the zone,and(3)ejection of coal mass or coal burst due to instability.Moreover,we figured out the initial strength of periodic cracks is parallel to the maximal dominant stress direction in the stress concentration zone and derived from the damage strain energy within the finite area of the zone based on the Griffith energy theory.In addition,we analyzed the formation process of the layered energy storage structure in the zone,simplified it as a simply supported restraint sheet,and calculated the minimum critical load and the internally accumulated elastic energy at the instable state.Furthermore,we established a criterion for occurrence of the coal burst based on the variational principle,and analyzed the coal mass ejection due to instability and coal burst induced by different intensity disturbances.At last,with the stratum conditions of Junde Coalmine as the model prototype,we numerically simulated the load displacement distribution of the stress concentration zone ahead of the working face disturbed by the main roof-fracture-induced dynamic load during the mining process as well as their varying characteristics,and qualitatively verified the above model.Dazhao Song Xueqiu He Enyuan Wang Zhenlei Li Menghan Wei Hongwei Mu 2019International Journal of Mining Science and Technology2019,29,4:1
9AFM characterization of surface mechanical and electrical properties of some common rocks显示文摘The characterization of micro-surface mechanical and electrical properties of the natural rock materials remains inadequate,and their macroscopic performance can be better comprehended by investigating the surface properties.With this purpose,the present research focuses on characterizing the microsurface morphology,Derjaguin-Muller-Toporov(DMT)modulus,adhesion,and potential of granite,shale,and limestone by employing the atomic force microscope(AFM)as a pioneer attempt.The results show that the micro-surface morphology of the rock fluctuates within hundreds of nanometers,among which the granite micro-surface is comparatively the smoothest,followed by limestone.The morphology of the shale is the roughest,indicating that the regional difference of shale micro-surface is dominant.The distribution of the adhesion on rock micro-surface is uneven;the average adhesion of eight measuring areas for shale is 23.93 n N,accounting for three times of granite and limestone,while the surface DMT modulus of shale is relatively lower than granite and limestone.It is inferred from the obtained results that higher surface adhesion is helpful to the gas adsorption of shale,and the lower surface DMT(elastic)modulus is useful to the formation of fractures and pores.Thus,these two are the micromechanical basis of shale gas adsorption.Additionally,introducing a method to reduce the surface adhesion will benefit the exploration of unconventional resources such as shale gas.The micro-surface of the three types of rocks all shows electricity,with average potential ranging from tens of millivolts to hundreds of millivolts.Besides,the micro-surface potential of the rocks are heterogeneous,and both positive and negative points can be found.The existence and uneven distribution of micro-surface potential provide a robust physical basis for the electromagnetic radiation generated by rock fracture under loading.This study offers a new method for revealing the adsorption characteristics of unconventional gas reservoir rocks and the electromagnetic radiation mechanism of the rock fracture.Xianghui Tian Xueqiu He Dazhao Song Zhenlei Li Majid Khan Huifang Liu Liming Qiu 2022International Journal of Mining Science and Technology2022,32,2:1
10Direct laser writing breaking diffraction barrier based on two-focus parallel peripheralphotoinhibition lithography显示文摘Direct laser writing(DLW)enables arbitrary three-dimensional nanofabrication.However,the diffraction limit poses a major obstacle for realizing nanometer-scale features.Furthermore,it is challenging to improve the fabrication efficiency using the currently prevalent single-focal-spot systems,which cannot perform high-throughput lithography.To overcome these challenges,a parallel peripheral-photoinhibition lithography system with a sub-40-nm two-dimensional feature size and a sub-20-nm suspended line width was developed in our study,based on two-photon polymerization DLW.The lithography efficiency of the developed system is twice that of conventional systems for both uniform and complex structures.The proposed system facilitates the realization of portable DLW with a higher resolution and throughput.Dazhao Zhu Liang Xu Chenliang Ding Zhenyao Yang Yiwei Qiu Chun Cao Hongyang He Jiawei Chen Mengbo Tang Lanxin Zhan Xiaoyi Zhang Qiuyuan Sun Chengpeng Ma Zhen Wei Wenjie Liu Xiang Fu Cuifang Kuang Haifeng Li Xu Liu 2022Advanced Photonics2022,4,6:1
11In vivo target protein degradation induced by PROTACs based on E3 ligase DCAF15显示文摘Dear Editor,As an emerging drug discovery paradigm,Proteolysis targeting chimeras(PROTACs)facilitate ubiquitination and degradation of the targets by cellular endogenous proteasome system.Compared with traditional small molecular inhibitors,PROTACs work like enzymes and can operate with or without functional inhibition of the targets,which endows this strategy to degrade drug targets,especially useful for“undruggable”ones.Liang Li Dazhao Mi Haixiang Pei Qiuhui Duan Xinyue Wang Wenbo Zhou Jianping Jin Dali Li Mingyao Liu Yihua Chen 2020Signal Transduction and Targeted Therapy2020,5,1:1
12Analysis of χ Phase Precipitation in Aged 2205 Duplex Stainless Steel显示文摘Analysis of χ phase precipitation in 2205 duplex stainless steel aged at 700 and 750 ℃ has been investigated systematically. The experimental results showed that χ phase forms prior to the precipitation of σ phase and disappears once σ phase starts to precipitate. This phenomenon indicates that σ phase nucleated and consumed the χ phase. The σ phase nucleated mainly at ferrite/austenite interface and grew inwards into the ferrite phase. The morphology of σ phase reveals a coral-like structure at the temperature of 700 ℃ for 120 min followed by quenching in water. The decomposition of ferrite occurs via the following eutectoid reaction: F→σ+γ2. The selected area diffraction pattern of zone axes is[ 1 ]χ||[ 1 ]δ, indicating a characteristic orientation relationship between χ phase and δ-ferrite.刘和平 SUN Hu'er LIU Bin LI Dazhao SUN Fenger ZHANG Yongtao 2015Journal of Wuhan University of Technology(Materials Science)2015,30,3:1
13Variations in the Microstructure and Properties of Mn-Ti Multiple-phase Steel with High Strength under Different Tempering Temperatures显示文摘There are few relevant researches on coils by tempering,and the variations of microstructure and properties of steel coil during the tempering process also remain unclear.By using thermo-mechanical control process(TMCP)technology,Mn-Ti typical HSLA steel coils with yield strength of 920 MPa are produced on the 2250 hot rolling production line.Then,the samples are taken from the coils and tempered at the temperatures of 220℃,350℃,and 620℃respectively.After tempering the strength,ductility and toughness of samples are tested,and meanwhile microstructures are investigated.Precipitates initially emerge inside the ferrite laths and the density of the dislocation drops.Then,the lath-shaped ferrites begin to gather,and the retained austenite films start to decompose.Finally,the retained austenite films are completely decomposed into coarse and short rod-shape precipitates composed of C and Ti compounds.The yield strength increases with increasing tempering temperature due to the pinning effect of the precipitates,and the dislocation density decreases.The yield strength is highest when the steel is tempered at 220℃because of pinning of the precipitates to dislocations.The total elongation increases in all samples because of the development of ferrites during tempering.The tensile strength and impact absorbed energy decline because the effect of impeding crack propagation weakens as the retained austenite films completely decompose and the precipitates coarsen.This paper clarifies the influence of different tempering temperatures on phase transformation characteristics and process of Mn-Ti typical multiphase steels,as well as its resulting performance variation rules.LI Dazhao LI Xiaonan CUI Tianxie LI Jianmin WANG Yutian FU Peimao 2015Chinese Journal of Mechanical Engineering2015,28,2:1
14DNA damage-mediated cellular senescence promotes hand-foot syndrome that can be relieved by thymidine prodrug显示文摘Hand-foot syndrome(HFS)is a widely recognized dose-limiting cutaneous toxicity effect of fluoropyrimidine chemotherapy agents that impairs clinical benefits and treatment outcomes.Even though the cause and pathophysiology of HFS are relatively widely reported,how the toxicity of fluoropyrimidine translates into persistent inflammation has not been studied.Additionally,prevention and treatment strategies for HFS based on its mechanistic occurrence and development are scarce.In our study,we demonstrated that cGAS-STING signaling pathway-mediated cellular senescence played a critical role in the inflammatory reaction and provided a therapeutic solution for HFS.Mechanistically,DNA damage,as the primary cytotoxic cause,in keratinocytes induces cell cycle arrest,activates the cGAS-STING signaling pathway,and subsequently mediates cellular senescence,ultimately fueling a robust secondary inflammatory response that results in HFS.More importantly,the thymidine prodrug thymidine diacetate was proven to be effective in preventing HFS by compensating for thymidylate deficiency to facilitate the replication and repair of DNA and thus causing the escape from cellular senescence.These data highlight the importance of DNA damage-mediated cellular senescence in the etiology of HFS and provide a potential therapeutic anchor point for fluoropyrimidine-induced HFS.Bingxue Yang Xinran Xie Zhaoyu Wu Dazhao Lv Jiajun Hu Yuyun Chen Jiaxing Li Shuyue Luo Jiacheng Li Jie Luo Shiyi Zhang 2023Genes & Diseases2023,10,6:0
15A method to predict rockburst using temporal trend test and its application显示文摘Rockbursts have become a significant hazard in underground mining,underscoring the need for a robust early warning model to ensure safety management.This study presents a novel approach for rockburst prediction,integrating the Mann-Kendall trend test(MKT)and multi-indices fusion to enable real-time and quantitative assessment of rockburst hazards.The methodology employed in this study involves the development of a comprehensive precursory index library for rockbursts.The MKT is then applied to analyze the real-time trend of each index,with adherence to rockburst characterization laws serving as the warning criterion.By employing a confusion matrix,the warning effectiveness of each index is assessed,enabling index preference determination.Ultimately,the integrated rockburst hazard index Q is derived through data fusion.The results demonstrate that the proposed model achieves a warning effectiveness of 0.563 for Q,surpassing the performance of any individual index.Moreover,the model’s adaptability and scalability are enhanced through periodic updates driven by actual field monitoring data,making it suitable for complex underground working environments.By providing an efficient and accurate basis for decision-making,the proposed model holds great potential for the prevention and control of rockbursts.It offers a valuable tool for enhancing safety measures in underground mining operations.Yarong Xue Zhenlei Li Dazhao Song Xueqiu He Honglei Wang Chao Zhou Jianqiang Chen Aleksei Sobolev 2024Journal of Rock Mechanics and Geotechnical Engineering2024,16,3:0
16Molecular mapping of a novel wheat powdery mildew resistance gene Ml92145E8-9 and its application in wheat breeding by marker-assisted selection显示文摘Powdery mildew, caused by Blumeria graminis f. sp. tritici(Bgt), is one of the most devastating diseases of common wheat(Triticum aestivum L.). The wheat line 92145 E8-9 is immune to Bgt isolate E09. Genetic analysis reveals that the powdery mildew resistance in 92145 E8-9 is controlled by a single dominant gene, temporarily designated Ml92145 E8-9. Bulkedsegregant analysis(BSA) with simple sequence repeat(SSR) markers indicates that Ml92145 E8-9 is located on chromosome 2 AL. According to the reactions of 92145 E8-9,VPM1(Pm4 b carrier), and Lankao 906(PmLK906 carrier) to 14 Bgt isolates, the resistance spectrum of 92145 E8-9 differs from those of Pm4 b and PmLK906, both of which were previously localized to 2 AL. To test the allelism among Ml92145 E8-9, Pm4 b and PmLK906, two F2 populations of 92145 E8-9 × VPM1(Pm4 b) and 92145 E8-9 × Lankao 906(PmLK906) were developed in this study. Screening of 784 F2 progeny of 92145 E8-9 × VPM1 and 973 F2 progeny of 92145 E8-9 × Lankao 906 for Bgt isolate E09 identified 37 and 19 susceptible plants, respectively. These findings indicated that Ml92145 E8-9 is non-allelic to either Pm4 b or PmLK906. Thus, Ml92145 E8-9 is likely to be a new powdery mildew resistance gene on2 AL. New polymorphic markers were developed based on the collinearity of genomic regions of Ml92145 E8-9 with the reference sequences of the International Wheat Genome Sequencing Consortium(IWGSC). Ml92145 E8-9 was mapped to a 3.6 c M interval flanked by molecular markers Xsdauk13 and Xsdauk682. This study also developed five powdery mildew-resistant wheat lines(SDAU3561, SDAU3562, SDAU4173, SDAU4174, and SDAU4175)using flanking marker-aided selection. The markers closely linked to Ml92145 E8-9 would be useful in marker-assisted selection for wheat powdery mildew resistance breeding.Xiaocheng Yu Shizhong Ren Lanfei Zhao Jun Guo Yinguang Bao Yingxue Ma Hongwei Wang Herbert W.Ohm Dazhao Yu Hongjie Li Lingrang Kong 2018The Crop Journal2018,6,6:0
17Characteristics of electromagnetic vector field generated from rock fracturing显示文摘Rock fracturing is often accompanied by electromagnetic phenomenon.As a vector field,in addition to the intensity that is widely concerned,the generated electromagnetic field also has obvious direction-ality.To this end,a set of electromagnetic antennas capable of simultaneous three-axis measurement is used to monitor the electromagnetic vector field generated from rock fracturing based on Brazilian tests.The signal amplitude on each axis can represent the magnitude of actual magnetic flux density component on the three axes.The intensity and directional characteristics of electromagnetic signals received at different positions are studied using vector synthesis.The directionality of electromagnetic radiation measured using a three-axis electromagnetic antenna shows that the direction of the magnetic flux intensity generated by rock fracturing tends to be parallel to the crack surface,and the measured signal intensity is greater in a direction closer to the crack surface.Menghan Wei Dazhao Song Xueqiu He Quan Lou Liming Qiu Zhenlei Li 2023Journal of Rock Mechanics and Geotechnical Engineering2023,15,2:0
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