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Study on vibration reduction of two-scale system coupled with dynamic vibration absorber
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作者 Honglin WAN Xianghong LI Yongjun SHEN 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第8期1335-1352,共18页
The dynamic vibration absorber with inerter and grounded stiffness(IGDVA)is used to control a two-scale system subject to a weak periodic perturbation.The vibration suppression effect is remarkable.The amplitude of th... The dynamic vibration absorber with inerter and grounded stiffness(IGDVA)is used to control a two-scale system subject to a weak periodic perturbation.The vibration suppression effect is remarkable.The amplitude of the main system coupled with absorber is significantly reduced,and the high frequency vibration completely disappears.First,through the slow-fast analysis and stability theory,it is found that the stability of the autonomous system exerts a notable regulating effect on the vibration response of the non-autonomous system.After adding the dynamic vibrator absorber,the center in the autonomous system changes to an asymptotically stable focus,consequently suppressing the vibration in the non-autonomous system.Further research reveals that the parameters of the absorber affect the real parts of the eigenvalues of the autonomous system,thereby regulating the stability of the system.Transitioning from a qualitative standpoint to a quantitative approach,a comparison of the solutions before and after the introduction of the dynamic absorber reveals that,when the grounded stiffness ratio and the mass ratio of the dynamic absorber are not equal,the high-frequency part in the analytical solution disappears.As a result,this leads to a reduction in the amplitude of the trajectory,achieving a vibration reduction effect. 展开更多
关键词 two-scale system dynamic vibration absorber vibration control inerter
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Dynamic performance and parameter optimization of a half-vehicle system coupled with an inerter-based X-structure nonlinear energy sink
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作者 Yong WANG Peili WANG +1 位作者 Haodong MENG Liqun CHEN 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第1期85-110,共26页
Inspired by the demand of improving the riding comfort and meeting the lightweight design of the vehicle, an inerter-based X-structure nonlinear energy sink(IXNES) is proposed and applied in the half-vehicle system to... Inspired by the demand of improving the riding comfort and meeting the lightweight design of the vehicle, an inerter-based X-structure nonlinear energy sink(IXNES) is proposed and applied in the half-vehicle system to enhance the dynamic performance. The X-structure is used as a mechanism to realize the nonlinear stiffness characteristic of the NES, which can realize the flexibility, adjustability, high efficiency, and easy operation of nonlinear stiffness, and is convenient to apply in the vehicle suspension, and the inerter is applied to replacing the mass of the NES based on the mass amplification characteristic. The dynamic model of the half-vehicle system coupled with the IX-NES is established with the Lagrange theory, and the harmonic balance method(HBM) and the pseudo-arc-length method(PALM) are used to obtain the dynamic response under road harmonic excitation. The corresponding dynamic performance under road harmonic and random excitation is evaluated by six performance indices, and compared with that of the original half-vehicle system to show the benefits of the IX-NES. Furthermore, the structural parameters of the IX-NES are optimized with the genetic algorithm. The results show that for road harmonic and random excitation, using the IX-NES can greatly reduce the resonance peaks and root mean square(RMS) values of the front and rear suspension deflections and the front and rear dynamic tire loads, while the resonance peaks and RMS values of the vehicle body vertical and pitching accelerations are slightly larger.When the structural parameters of the IX-NES are optimized, the vehicle body vertical and pitching accelerations of the half-vehicle system could reduce by 2.41% and 1.16%,respectively, and the other dynamic performance indices are within the reasonable ranges.Thus, the IX-NES combines the advantages of the inerter, X-structure, and NES, which improves the dynamic performance of the half-vehicle system and provides an effective option for vibration attenuation in the vehicle engineering. 展开更多
关键词 inerter X-structure nonlinear energy sink(NES) half-vehicle system dynamic performance
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Experimental study of an aircraft fuel tank inerting system 被引量:16
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作者 Cai Yan Bu Xueqin +3 位作者 Lin Guiping Sun Bing Zeng Yu Li Zixuan 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2015年第2期394-402,共9页
In this work, a simulated aircraft fuel tank inerting system has been successfully estab- lished based on a model tank. Experiments were conducted to investigate the influences of different operating parameters on the... In this work, a simulated aircraft fuel tank inerting system has been successfully estab- lished based on a model tank. Experiments were conducted to investigate the influences of different operating parameters on the inerting effectiveness of the system, including flow rate of the inert gas (nitrogen-enriched air), inert gas concentration, fuel load of the tank and different inerting approaches. The experimental results show that under the same operating conditions, the time span of a complete inerting process decreased as the flow rate of inert gas was increased; the time span using the inert gas with 5% oxygen concentration was much longer than that using pure nitrogen; when the fuel tank was inerted using the ullage washing approach, the time span increased as the fuel load was decreased; the ullage washing approach showed the best inerting performance when the time span of a complete inerting process was the evaluation criterion, but when the decrease of dissolved oxygen concentration in the fuel was also considered to characterize the inerting effective- ness, the approach of ullage washing and fuel scrubbing at the same time was the most effective. 展开更多
关键词 Flow rate Fuel tank Inert Oxygen concentration Time span Ullage
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Effect of fuel type on the performance of an aircraft fuel tank oxygen-consuming inerting system 被引量:2
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作者 Xiaotian PENG Shiyu FENG +2 位作者 Chaoyue LI Chen CHEN Weihua LIU 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2021年第3期82-93,共12页
The properties of aviation fuel have a great influence on the performance of oxygenconsuming inerting systems. Based on the establishment of the catalytic inerting process, the flow relationship of each gas component ... The properties of aviation fuel have a great influence on the performance of oxygenconsuming inerting systems. Based on the establishment of the catalytic inerting process, the flow relationship of each gas component flowing through the catalytic reactor was derived. The mathematical model of the gas concentration in the gas phase of the fuel tank was established based on the mass conservation equation, and the fuel tank model was verified by performing experiments.The results showed that the fuel type exerts a considerably higher influence on the performance of the oxygen-consuming inerting system compared to the corresponding influence on the hollow fiber membrane system, and the relative magnitude of the inerting rates of the four fuel types is RP5 > RP3 > RP6 > JP8. In addition, a higher catalytic efficiency or fuel load rate corresponds to a higher rate of decrease of the oxygen concentration in the gas phase, and the inerting time is inversely proportional to the suction flow rate of the fan. When different fuels are used, the amount of cooling gas and water released from the inerting system are different. Therefore, the influence of fuel type on the system performance should be extensively considered in the future. 展开更多
关键词 Aviation fuel Catalytic reactions Hollow fiber membrane Inert gas Mathematical model
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Revealing the specific role of sulfide and nano-alumina in composite solid-state electrolytes for performance-reinforced ether-nitrile copolymers
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作者 Haoyang Yuan Changhao Tian +3 位作者 Mengyuan Song Wenjun Lin Tao Huang Aishui Yu 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第4期628-636,共9页
Composite solid-state electrolytes represent a critical pathway that balances the interface compatibility and lithium-ion conductivity in all-solid-state batteries.The quest for stable and highly ion-conductive combin... Composite solid-state electrolytes represent a critical pathway that balances the interface compatibility and lithium-ion conductivity in all-solid-state batteries.The quest for stable and highly ion-conductive combinations between polymers and fillers is vital,but blind attempts are often made due to a lack of understanding of the mechanisms involved in the interaction between polymers and fillers.Herein,we employ in-situ polymerization to prepare a polymer based on an ether-nitrile copolymer with high cathode stability as the foundation and discuss the performance enhancement mechanisms of argyrodite and nano-alumina.With 1%content of sulfide interacting with the polymer at the two-phase interface,the local enhancement of lithium-ion migration capability can be achieved,avoiding the reduction in capacity due to the low ion conductivity of the passivation layer during cycling.The capacity retention after 50cycles at 0.5 C increases from 83.5%to 94.4%.Nano-alumina,through anchoring the anions and interface inhibition functions,eventually poses an initial discharge capacity of 136.8 m A h g^(-1)at 0.5 C and extends the cycling time to 1000 h without short-circuiting in lithium metal batteries.Through the combined action of dual fillers on the composite solid-state electrolyte,promising insights are provided for future material design. 展开更多
关键词 Composite solid-state electrolytes Lithium metal anode Dual fillers Interfacial ionic conduction Inert nano-alumina
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Copper-Mediated Selective Multiple Inert Chemical Bonds Cleavage for Cyanation of Indoles via Tandem Carbon and Nitrogen Atom Transfer
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作者 Shimin Xie Fangfang Cai +3 位作者 Lixin Liu Lebin Su Jianyu Dong Yongbo Zhou 《Chinese Journal of Chemistry》 SCIE CAS CSCD 2024年第19期2299-2304,共6页
Comprehensive Summary The activation of inert chemical bonds is an exciting area of research in chemistry because it enables the direct utilization of readily available starting materials and promotes atom-and step-ec... Comprehensive Summary The activation of inert chemical bonds is an exciting area of research in chemistry because it enables the direct utilization of readily available starting materials and promotes atom-and step-economic synthesis.Undoubtedly,selectively activating and transforming multiple inert chemical bonds is an even more intriguing and demanding task in synthetic chemistry.However,due to its inherent complexity and extreme challenges,this endeavour is rarely accomplished.We report a copper-mediated complete cleavage and selective transformation of multiple inert chemical bonds of three easily available feedstocks,i.e.,a sp2C—H bond in indoles,three sp3C—H bonds and one C—N bond in a methyl carbon atom in TMEDA,and the C≡N triple bond in CH_(3)CN.This reaction proceeds via tandem carbon and nitrogen atom transfer,and allows for the direct and efficient cyanation of indoles,presenting a simple and direct alternative for synthesizing 3-cyanoindoles. 展开更多
关键词 Multiple inert chemical bonds Bond cleavage Carbon and nitrogen atom transfer Cleavage reactions Oxidation Copper Cyanation IndoleSelectivity
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Parameters Optimization and Performance Evaluation of the Tuned Inerter Damper for the Seismic Protection of Adjacent Building Structures
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作者 Xiaofang Kang Jian Wu +1 位作者 Xinqi Wang Shancheng Lei 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第1期551-593,共43页
In order to improve the seismic performance of adjacent buildings,two types of tuned inerter damper(TID)damping systems for adjacent buildings are proposed,which are composed of springs,inerter devices and dampers in ... In order to improve the seismic performance of adjacent buildings,two types of tuned inerter damper(TID)damping systems for adjacent buildings are proposed,which are composed of springs,inerter devices and dampers in serial or in parallel.The dynamic equations of TID adjacent building damping systems were derived,and the H2 norm criterion was used to optimize and adjust them,so that the system had the optimum damping performance under white noise random excitation.Taking TID frequency ratio and damping ratio as optimization parameters,the optimum analytical solutions of the displacement frequency response of the undamped structure under white noise excitation were obtained.The results showed that compared with the classic TMD,TID could obtain a better damping effect in the adjacent buildings.Comparing the TIDs composed of serial or parallel,it was found that the parallel TIDs had more significant advantages in controlling the peak displacement frequency response,while the H2 norm of the displacement frequency response of the damping system under the coupling of serial TID was smaller.Taking the adjacent building composed of two ten-story frame structures as an example,the displacement and energy collection time history analysis of the adjacent building coupled with the optimum design parameter TIDs were carried out.It was found that TID had a better damping effect in the full-time range compared with the classic TMD.This paper also studied the potential power of TID in adjacent buildings,which can be converted into available power resources during earthquakes. 展开更多
关键词 Adjacent buildings tuned inerter damper(TID) H2 norm optimization vibration control energy harvesting
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Robust Particle Swarm Optimization Algorithm for Modeling the Effectof Oxides Thermal Properties on AMIG 304L Stainless Steel Welds
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作者 Rachid Djoudjou Abdeljlil Chihaoui Hedhibi +3 位作者 Kamel Touileb Abousoufiane Ouis Sahbi Boubaker Hani Said Abdo 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第11期1809-1825,共17页
There are several advantages to the MIG(Metal Inert Gas)process,which explains its increased use in variouswelding sectors,such as automotive,marine,and construction.A variant of the MIG process,where the sameequipmen... There are several advantages to the MIG(Metal Inert Gas)process,which explains its increased use in variouswelding sectors,such as automotive,marine,and construction.A variant of the MIG process,where the sameequipment is employed except for the deposition of a thin layer of flux before the welding operation,is the AMIG(Activated Metal Inert Gas)technique.This study focuses on investigating the impact of physical properties ofindividual metallic oxide fluxes for 304L stainless steel welding joint morphology and to what extent it can helpdetermine a relationship among weld depth penetration,the aspect ratio,and the input physical properties ofthe oxides.Five types of oxides,TiO_(2),SiO_(2),Fe_(2)O_(3),Cr_(2)O_(3),and Mn_(2)O_(3),are tested on butt joint design withoutpreparation of the edges.A robust algorithm based on the particle swarm optimization(PSO)technique is appliedto optimally tune the models’parameters,such as the quadratic error between the actual outputs(depth and aspectratio),and the error estimated by the models’outputs is minimized.The results showed that the proposed PSOmodel is first and foremost robust against uncertainties in measurement devices and modeling errors,and second,that it is capable of accurately representing and quantifying the weld depth penetration and the weld aspect ratioto the oxides’thermal properties. 展开更多
关键词 Activated metal inert gas welding stainless steel activating flux oxides’thermal properties particle swarm optimization
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气相色谱法测定氟苯尼考中二乙胺和三乙胺残留
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作者 谭跃浪 胡克斌 +4 位作者 韦晶晶 陈蕾 张俊梅 张春侠 吴寒梅 《精细化工中间体》 CAS 2024年第3期84-88,共5页
建立气相色谱法测定氟苯尼考中二乙胺和三乙胺残留的方法。采用Inert Cap for Amines毛细管胺类测试柱,经惰性处理的衬管,载气为氮气,流速3.0 mL/min,分流比为5∶1,检测器为FID。结果表明:该方法中二乙胺、三乙胺与其相邻峰完全分离;对... 建立气相色谱法测定氟苯尼考中二乙胺和三乙胺残留的方法。采用Inert Cap for Amines毛细管胺类测试柱,经惰性处理的衬管,载气为氮气,流速3.0 mL/min,分流比为5∶1,检测器为FID。结果表明:该方法中二乙胺、三乙胺与其相邻峰完全分离;对照峰面积RSD均小于2%;二乙胺的检测限浓度为1.84μg/mL,定量限浓度为3.67μg/mL,在3.67~13.76μg/mL浓度范围内线性相关系数r为0.995 9;三乙胺的检测限浓度为0.50μg/mL,定量限浓度为1.50μg/mL,在1.50~374.63μg/mL浓度范围内线性相关系数r为0.998 6;二乙胺的回收率90.7%~103.0%,三乙胺的回收率90.8%~97.3%;小幅改变色谱条件,耐用性良好。方法操作简单、准确度高、重复性好,适用于氟苯尼考中二乙胺、三乙胺残留的测定。 展开更多
关键词 氟苯尼考 二乙胺 三乙胺 Inert Cap for Amines胺类测试柱
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From Unmanned Systems to Autonomous Intelligent Systems 被引量:18
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作者 Jie Chen Jian Sun Gang Wang 《Engineering》 SCIE EI CAS 2022年第5期16-19,共4页
1.Introduction Artificial intelligence(AI)is a rapidly growing field of technol-ogy,which“will enliven inert objects,much as electricity did more than a century ago.Everything that we formerly electrified will now co... 1.Introduction Artificial intelligence(AI)is a rapidly growing field of technol-ogy,which“will enliven inert objects,much as electricity did more than a century ago.Everything that we formerly electrified will now cognitize”[1].AI advances are constantly pushing the frontier of what machines can do.Increased attention is being placed on AI research,as well as its development and deployment by commer-cial investors,defense strategists,and policy makers[2]. 展开更多
关键词 FRONTIER inert POLICY
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THERMAL STRESSES RELAXATION DESIGN OF Ni/NiFe_(2)O_(4) SYSTEM FUNCTIONALLY GRADED CERMET INERT ANODE 被引量:4
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作者 J. Li Q.S. Zhang Y.Q. Lai S.L. Ye Y.X. Liu 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2005年第5期635-641,共7页
The thermal stresses relaxation of Ni/NiFe2O4 system functionally graded cermet inert anode for aluminum electrolysis was optimally designed. The transient thermal stresses of the inert anode under complex boundary co... The thermal stresses relaxation of Ni/NiFe2O4 system functionally graded cermet inert anode for aluminum electrolysis was optimally designed. The transient thermal stresses of the inert anode under complex boundary condition during high-temp (955℃) electrolysis were calculated using the finite-element software ANSYS, the influence of different parameters on the distribution of the thermal stresses were analyzed. The results showed that, during the process of thermal shock, the thermal hoop tensile stress on the surface of the anode is very large, which is possibly the major cause of anode crack; when the radius of the anode is between 0.05-0.15m, a range that can be realized by recent manufacturing technology, the optimum composition distribution exponent p is 0.25; The hoop tensile stresses reduce with the decrease of anode scale and also decrease with the decrease of the convection coefficient between the electrolyte and the anode. 展开更多
关键词 functionally graded material (FGM) transient thermal stresses ANSYS inert anode aluminum electrolysis
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Optimal design of inerter systems for the force-transmission suppression of oscillating structures
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作者 Zhang Ruifu Zhao Zhipeng +1 位作者 Lin Xuchuan Zhang Lingxin 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2022年第2期441-454,共14页
When dealing with the oscillations of fixed-base structures or machines induced by external forces,suppressing the vibrational impact on the adjacent structures and the environment helps to maintain the structural dur... When dealing with the oscillations of fixed-base structures or machines induced by external forces,suppressing the vibrational impact on the adjacent structures and the environment helps to maintain the structural durability and ensure the users′comfort level.This study proposed an inerter-based optimal solution to suppress the vibrational forces and energy transmitted to the supporting ground by utilizing the great potential of the inerter.For the external force,which contains various frequency bands,the stochastic response and an energy balance analysis are conducted to evaluate the force transmissibility,structural displacement,and vibration power flow.Given the benefits of the inerter,a transmitted-force-based optimal design framework is proposed for inerter systems,of which the effectiveness is validated by numerical examples.The obtained results show that inerter systems are capable of providing significant reductions in the structural displacement and the force transmitted to the supporting ground.Particularly,the closed-form power equation indicated that a grounded inerter can suppress the force transmission and vibrational energy,thus leading to a less negative impact on the ground and environment.Revealing the working mechanism and optimal design strategy of the inerter can help solve the force-transmission control problem experienced by some practical structures. 展开更多
关键词 inerter transmitted force oscillating structure optimal design
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Study on the Inert Coordination Compound in the System of“Molybdenum(Ⅵ)—TAE—Hydroxylamine”and its Analytical Application
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作者 Chen Huaxu Shao Guangdi Department of Chemistry,University of Science and Technology BeijingBai Linshan Department of Chemical Engineering,East China Institute of Metallurgy 《Rare Metals》 SCIE EI CAS CSCD 1989年第2期58-63,共6页
In the presence of ethyl alcohol or emulsifier OP,molybdenum(Ⅵ) forms 1∶1∶1'water soluble colored coordination com- pound with both of 2-(2-thiazolylazo)-5-diethylaminophenol (abbreviation TAE) and hydroxylamin... In the presence of ethyl alcohol or emulsifier OP,molybdenum(Ⅵ) forms 1∶1∶1'water soluble colored coordination com- pound with both of 2-(2-thiazolylazo)-5-diethylaminophenol (abbreviation TAE) and hydroxylamine.This deep blue coordination compound is inert characteristically and remains stable in 1.7 mol/L sulfuric acid,2.4 mol/L hydrochloric or ni- tric acid.It will not be decomposed by masking agents even on boiled,while in that case,almost all the colored coordination com- pounds formed by other metal ions will be decomposed completely.This inert character of the coordination compound of molybdenum(Ⅵ) and its utilization in improving the analytical selectivity have been discussed.In the coexistence of various for- eign ions,especially in the presence of a great quantity of tungsten,which always interferes with the determination of molybdenum,the direct determination of molybdenum in the aqueous solution by applying this system has shown an acceptable sensitivity and reproducibility.From the results of determination in some synthetic and standard samples,it seems feasible to use this system in the determination of molybdenum in nonferrous alloys. 展开更多
关键词 and its Analytical Application Molybdenum HYDROXYLAMINE Study on the Inert Coordination Compound in the system of TAE
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Theoretically Catalytic Synthesis of 5-Nitro-1,2,4-Triazol-3-One in Inert Gas Clustered System (X<sub>6</sub>, X = He, Ne)
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作者 Min-Hsien Liu Ming-Yung Wu 《Open Journal of Physical Chemistry》 2012年第2期107-116,共10页
Inert gas-clustered systems (Xn, X = He, Ne, Ar and n = 2 - 20) were established in this study and their stability as a result of interparticulate interaction was examined. Ferric chloride and ferrous oxides were used... Inert gas-clustered systems (Xn, X = He, Ne, Ar and n = 2 - 20) were established in this study and their stability as a result of interparticulate interaction was examined. Ferric chloride and ferrous oxides were used as catalysts to promote reaction, and 5-nitro-1,2,4-triazol-3-one (NTO) was theoretically synthesized under an inert gas (X6)-clustered environment in this study. The raw material, urea, initially underwent chlorination using chlorine as the reagent, followed by amination, formylation and nitration. Reaction routes closely related to the experimental processes were successfully constructed, and the corresponding energy barriers were estimated for each elementary reaction. The findings revealed that the average errors in the B3LYP/6-31G(d, p)-calculated geometry and vibrational frequency of NTO in an Ne6 system relative to the observed values were 0.83% and 1.84%, respectively. The neon gas-clustered system achieved greater stabilization, which results from the difference in self-consistent field energy (ESCF), than the corresponding stabilization acquired in a helium- or argon-based system. Ferric chloride serves as a good catalyst to reduce the energy barrier of the chlorination reaction, and ferrous oxide is suitable for catalyzing the amination, formylation and nitration reactions, although nitric acid is the better agent for nitration. The catalytic Ne6-clustered reaction system is suggested to be a more feasible pathway for the synthesis of NTO. 展开更多
关键词 NTO Inert Gas Clustered system Metal Catalyst FORMYLATION Reaction
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The effect of activating fluxes on the cathode spots in the activating TIG welding 被引量:1
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作者 黄勇 王伯洋 +4 位作者 郭建航 刘永刚 黄健康 樊丁 余淑荣 《China Welding》 CAS 2023年第1期7-17,共11页
The cathode spots are a common phenomenon in the TIG(tungsten inert gas)welding process.However,it is rarely observed in the activating TIG welding process.This research is mainly focused on the effect of activating f... The cathode spots are a common phenomenon in the TIG(tungsten inert gas)welding process.However,it is rarely observed in the activating TIG welding process.This research is mainly focused on the effect of activating flux on cathode spots in the activating TIG welding.The characteristics and behaviors of cathode spots were investigated in activating TIG welding by the high-speed camera and the spectrograph.Three kinds of oxide(TiO_(2),SiO_(2),MnO_(2))and two halide(MnCl_(2),CaF_(2))activating fluxes are used in the activating TIG welding process.The results show that differ from the TIG welding,the oxide activating flux increases the number of cathode spots and decreases the velocity.The effect is the opposite for the halide activating flux.Moreover,the number of spots no longer varies with the current except TiO2 activating flux.As the temperature of the weld pool surface increases the spot moves away from the center.But this rule is not valid when silica and manganese compounds activating fluxes are used.The variation of cathode spots is caused by the oxide film reformed and the distribution of weld slag.The formation mechanism of cathode spots might be the impact of ions on the cathode surface and the strong electric field formed near the cathode surface. 展开更多
关键词 cathode spots behaviors activating tungsten inert gas welding high-speed photography spectrum
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Geometrically nonlinear inerter for vibration suppression
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作者 Yuyang SONG Liqun CHEN Tianzhi YANG 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2023年第11期1871-1886,共16页
A two-degree-of-freedom(2DOF)vibration isolation structure with an integrated geometric nonlinear inerter(NI)device is proposed.The device is integrated into an inertial nonlinear energy sink(INES),and its vibration s... A two-degree-of-freedom(2DOF)vibration isolation structure with an integrated geometric nonlinear inerter(NI)device is proposed.The device is integrated into an inertial nonlinear energy sink(INES),and its vibration suppression performance is examined by the Runge-Kutta(RK)method and verified by the harmonic balance method(HBM).The new isolator is compared with a traditional vibration isolator.The results show a significant improvement in the vibration suppression performance.To investigate the effects of the excitation amplitude and initial condition on the dynamics of the system,a series of transmissibility-frequency response analyses are performed based on the displacement transmissibility.The energy flow of the system is analyzed,and numerous calculations reveal a series of ideal values for the energy sink in the NI-INES system.This study provides new insights for the design of vibration isolators. 展开更多
关键词 inerter nonlinear dynamic ISOLATOR ENERGY
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Vertical seismic absorber utilizing inertance and negative stiffness implemented with gas springs
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作者 Kalogerakou M Paradeisiotis A Antoniadis I 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2023年第1期225-241,共17页
A novel implementation of negative stiffness elements(NSEs)is proposed,utilizing industrial grade nitrogen gas springs as pre-stressed stiffness elements in a configuration with lever arms.This NSE is combined with an... A novel implementation of negative stiffness elements(NSEs)is proposed,utilizing industrial grade nitrogen gas springs as pre-stressed stiffness elements in a configuration with lever arms.This NSE is combined with an inerter to form a stiff dynamic absorber(SDA)for vertical seismic protection of structures with base isolation.The SDA is optimized to minimize vertical accelerations while ensuring static structural integrity,excellent damping performance and containment of relative displacements.The introduction of gas springs in place of conventional linear springs addresses important practical limitations through features of non-linearity and industrial grade manufacturing.The proposed implementation is dimensioned for a 50-ton structure and evaluated numerically for 25 actual earthquake records,in comparison with a linear SDA model and an equivalent conventional damper(CD).Individual and averaged results of acceleration and displacement time histories demonstrate vastly superior response compared to CD regarding induced accelerations for similar displacements.Performance equivalency with the linear SDA model indicates the stability of the gas spring implementation while guaranteeing predictability,tested endurance,proper tolerances,and off-axis motion resistance without requiring additional guiding components,as opposed to conventional springs.These features render the proposed implementation a promising solution for the realization of NSEs in seismic protection. 展开更多
关键词 negative stiffness gas springs vertical seismic protection KDamper inerter
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Comparative study on the flame retardancy of CO_(2) and N_(2) during coal adiabatic oxidation process
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作者 Xiyang Fang Bo Tan Haiyan Wang 《International Journal of Coal Science & Technology》 EI CAS CSCD 2023年第4期254-264,共11页
To test the effectiveness of N_(2) and CO_(2) in preventing coal from spontaneously combusting,researchers used an adiabatic oxidation apparatus to conduct an experiment with different temperature starting points.Non-... To test the effectiveness of N_(2) and CO_(2) in preventing coal from spontaneously combusting,researchers used an adiabatic oxidation apparatus to conduct an experiment with different temperature starting points.Non-adsorbed helium(He)was used as a reference gas,and coal and oxygen concentration temperature variations were analyzed after inerting.The results showed that He had the best cooling effect,N_(2) was second,and CO_(2) was the worst.At 70℃and 110℃,the impact of different gases on reducing oxygen concentration and the cooling effect was the same.However,at the starting temperature of 150℃,CO_(2) was less effective in lowering oxygen concentration at the later stage than He and N_(2).N_(2) and CO_(2) can prolong the flame retardation time of inert gas and reduce oxygen displacement with an initial temperature increase.When the starting temperature is the same,N_(2) injection cools coal samples and replaces oxygen more effectively than CO_(2) injection.The flame retardancy of inert gas is the combined result of the cooling effect of inert gas and the replacement of oxygen.These findings are essential for using inert flame retardant technology in the goaf. 展开更多
关键词 Coal spontaneous combustion Adiabatic oxidation Inert gas flame retardant Flame retardant efficiency REPLACEMENT
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Separator Dependency on Cycling Stability of Lithium Metal Batteries Under Practical Conditions
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作者 Hyeongguk An Youngjoon Roh +5 位作者 Youngseong Jo Hyuntae Lee Minhong Lim Mingyu Lee Yong Min Lee Hongkyung Lee 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2023年第5期307-316,共10页
Development of practical lithium(Li)metal batteries(LMBs)remains challenging despite promises of Li metal anodes(LMAs),owing to Li dendrite formation and highly reactive surface nature.Polyolefin separators used in LM... Development of practical lithium(Li)metal batteries(LMBs)remains challenging despite promises of Li metal anodes(LMAs),owing to Li dendrite formation and highly reactive surface nature.Polyolefin separators used in LMBs may undergo severe mechanical and chemical deterioration when contacting with LMAs.To identify the best polyolefin separator for LMBs,this study investigated the separator-deterministic cycling stability of LMBs under practical conditions,and redefined the key influencing factors,including pore structure,mechanical stability,and chemical affinity,using 12 different commercial separators,including polyethylene(PE),polypropylene(PP),and coated separators.At extreme compression triggered by LMA swelling,isotropic stress release by balancing the machine direction and transverse direction tensile strengths was found to be crucial for mitigating cell short-circuiting.Instead of PP separators,a PE separator that possesses a high elastic modulus and a highly connected pore structure can uniformly regulate LMA swelling.The ceramic coating reinforced short-circuiting resistance,while the cycling efficiency degraded rapidly owing to the detrimental interactions between ceramics and LMAs.This study identified the design principle of separators for practical LMBs with respect to mechanical stability and chemical affinity toward LMAs by elucidating the impacts of separator modification on the cycling performance. 展开更多
关键词 chemical inertness lithium metal batteries mechanical strength polyolefin separators short-circuiting
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A Fuzzy Logic Approach to Predict Tensile Strength in TIG Mild Steel Welds
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作者 Ademola Adebiyi Oyinbade Kehinde Ademola Imoukhuede Abdulateef Olufolahan Akadiri 《World Journal of Engineering and Technology》 2023年第2期199-207,共6页
Welding defects influence the desired properties of welded joints giving fabrication experts a common problem of not being able to produce weld structures with optimal strength and quality. In this study, the fuz... Welding defects influence the desired properties of welded joints giving fabrication experts a common problem of not being able to produce weld structures with optimal strength and quality. In this study, the fuzzy logic system was employed to predict welding tensile strength. 30 sets of welding experiments were conducted and tensile strength data was collected which were converted from crisp variables into fuzzy sets. The result showed that the fuzzy logic tool is a highly effective tool for predicting tensile strength present in TIG mild steel weld having a coefficient of determination value of 99%. 展开更多
关键词 Tensile Strength PREDICT Steel Fuzzy Logic Tungsten Inert Gas Welding
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