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Influence of pressure disturbance wave on dynamic response characteristics of liquid film seal for multiphase pump

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Petroleum Science 2024年第3期21卷 2048-2065页

作者： Qing-ping Li jin-Ya Zhang Jia-Xiang Zhang yong-Xue Zhang CNOOC Research Institute Company Limited Beijing100028China State Key Laboratory of Natural Gas Hydrate Beijing100028China College of Mechanical and Transportation Engineering China University of PetroleumBeijing2249China

Slug flow or high GVF(Gas Volume Fraction)conditions can cause pressure disturbance waves and alternating loads at the boundary of mechanical seals for multiphase pumps,endangering the safety of multiphase pump *** mechanical seal model is simplified by using periodic boundary conditions and numerical calculations are carried out based on the Zwart-Gerber-Belamri cavitation ***(User Define Function)programs such as structural dynamics equations,alternating load equations,and pressure disturbance equations are embedded in numerical calculations,and the dynamic response characteristics of mechanical seal are studied using layered dynamic mesh *** results show that when the pressure disturbance occurs at the inlet,as the amplitude and period of the disturbance increase,the film thickness gradually *** the fundamental reason for the hysteresis of the film thickness change is that the pressure in the high-pressure area cannot be restored in a timely *** maximum value of leakage and the minimum value of axial velocity are independent of the disturbance period and determined by the disturbance *** mutual interference between enhanced waves does not have a significant impact on the film thickness,while the front wave in the attenuated wave has a promoting effect on the subsequent film thickness changes,and the fluctuation of the liquid film cavitation rate and axial velocity under the attenuated wave condition deviates from the initial *** with pressure disturbance conditions,alternating load conditions have a more significant impact on film thickness and *** actual operation,it is necessary to avoid alternating load conditions in multiphase pump mechanical seals.

关键词： Multiphase pump Liquid film seal Pressure disturbance wave Dynamic response characteristics

3D-structured carbon nanotube fibers as ultra-robust fabrics for adaptive electromagnetic shielding

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Nano Research 2024年第9期17卷 8521-8530页

作者： Dongping Li ping Wang Yuanyuan Li Zhenzhong yong Kunjie Wu Yan Zhang jin Wang Dongmei Hu Key Laboratory of Multifunctional and Smart Systems Suzhou Institute of Nano-Tech and Nano-BionicsChinese Academy of SciencesSuzhou 215123China College of Textile and Clothing Engineering of Soochow University Suzhou 215021China

Wireless communication technology is indispensable in our daily lives,but it also results in serious electromagnetic radiation ***,developing smart electromagnetic interference shielding materials with adjustable electromagnetic wave(EMW)responses holds significant promise for future electromagnetic shielding *** this study,we propose an electromagnetic shielding switch(ESS)characterized by tunable electromagnetic shielding performance achieved by fabricating a three-dimensional(3D)carbon nanotube-based spacer fabric(CNT-SF)and modifying CNT-SF with chemical vapor deposition(CCNT-SF).The CCNT-SF displays direction-dependent electrical conductivity by manipulating the warp and weft density,measuring 128 S/m transversely and 447 S/m *** characteristic allows the CCNT-SF to transmit or shield EMW by adjusting the angle of EMW incidence through fabric rotation,resulting in anisotropic electromagnetic shielding performance(33 dB transversely and 87 dB vertically).This feature enables switchable shielding with an on/off ratio of ***,the unique 3D structure confers excellent mechanical properties on the fabric,with compressive strength reaching 120 *** a flexible,lightweight,and mechanically robust ESS,the CCNT-SF holds promising prospects for mitigating the challenges of increasingly severe and intricate electromagnetic environments.

关键词： carbon nanotube spacer fabric electromagnetic shielding impact resistance joule heating electromagnetic shielding switch

Gas sensor array based on carbon-based thin-film transistor for selective detection of indoor harmful gases

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Rare Metals 2024年第9期43卷 4401-4411页

作者： Can Liu Yu Sun Jia-Yi Guo Xiu-Lei Li Lu Tao jin-yong Hu Jue-Xian Cao ping-Hua Tang yong Zhang School of Electrical and Information Engineering Hunan Institute of EngineeringXiangtan 411104China Physics and Optoelectronics&Hunan Institute of Advanced Sensing and Information Technology Xiangtan UniversityXiangtan 411105China

The identification of indoor harmful gases is imperative due to their significant threats to human health and *** achieve accurate identification,an effective strategy of constructing a sensor array combined with the pattern recognition algorithm is ***-based thin-film transistors are selected as the sensor array unit,with semiconductor carbon nanotubes(CNTs)within the TFT channels modified with different metals(Au,Cu and Ti)for selective responses to NH_(3),H_(2)S and HCHO,*** accurate gas species identification,an identification mode that combines linear discriminant analysis algorithms and logistic regression classifier is *** test results demonstrate that by preprocessing the sensor array’s sensing data with the LDA algorithm and subsequently employing the LR classifier for identification,a 100%recognition rate can be achieved for three target gases(NH3,H2S and HCHO).This work provides significant guidance for future applications of chip-level gas sensors in the realms of the Internet of Things and Artificial Intelligence.

关键词： Carbon-based thin-film transistors Gas sensor arrays Semiconductor carbon nanotubes Multi-gas detection Linear discriminant analysis

High-order Soliton Matrix for the Third-order Flow Equation of the Gerdjikov-Ivanov Hierarchy Through the Riemann-Hilbert Method

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Acta Mathematicae Applicatae Sinica 2024年第2期40卷 358-378页

作者： jin-yan ZHU yong CHEN School of Mathematical Sciences Shanghai Key Laboratory of Pure Mathematics and Mathematical PracticeEast China Normal UniversityShanghai 200062China College of Mathematics and Systems Science Shandong University of Science and TechnologyQingdao 266590China

The Gerdjikov-Ivanov(GI)hierarchy is derived via recursion operator,in this article,we mainly investigate the third-order flow GI *** the framework of the Riemann-Hilbert method,the soliton matrices of the third-order flow GI equation with simple zeros and elementary high-order zeros of Riemann-Hilbert problem are constructed through the standard dressing *** advantage of this result,some properties and asymptotic analysis of single soliton solution and two soliton solution are discussed,and the simple elastic interaction of two soliton are *** with soliton solution of the classical second-order flow,we find that the higher-order dispersion term affects the propagation velocity,propagation direction and amplitude of the ***,by means of a certain limit technique,the high-order soliton solution matrix for the third-order flow GI equation is derived.

关键词： Gerdjikov-Ivanov hierarchy third-order flow GI equation Riemann-Hilbert method high-order soliton

Development of a high-repetition-rate lumped-inductance kicker magnet prototype for the beam switchyard of SHINE

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Nuclear Science and Techniques 2024年第2期35卷 20-31页

作者： yong-Fang Liu Rui-ping Wang jin Tong Bo Zhang Si Chen Qi-Bing Yuan Hai-Xiao Deng Ming Gu Bo Liu Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai 201412People’s Republic of China

The Shanghai high-repetition-rate X-ray free-electron laser and extreme light facility(SHINE)operates at a maximum repetition rate of 1 *** magnets are key components that distribute electron bunches into three different undulator lines in a bunch-by-bunch *** kicker field width must be less than the time interval between bunches.A lumpedinductance kicker prototype was developed using a vacuum chamber with a single-turn *** full magnetic field strength was 0.005 *** paper presents the requirements,design considerations,design parameters,magnetic field calculations,and measurements of the kicker *** relevant experimental results are also *** pulse width of the magnetic field was approximately 600 ns,and the maximum operation repetition rate was 1 *** developed kicker satisfies the requirements for the SHINE ***,numerous recommendations for the future optimization of kicker magnets are provided.

关键词： X-ray free-electron laser Kicker magnet Beam switchyard High repetition rate Ni-Zn ferrites

Investigation of acoustic attributes based on preference and perceptional acoustics of Korean traditional halls for optimal design solutions

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Building Simulation 2024年第5期17卷 723-738页

作者： Beta Bayu Santika Haram Lee jin yong Jeon Department of Architectural Engineering Hanyang UniversitySeoul 04763R.O.Korea

Immersed in the rich tapestry of traditional culture,Gugak,the traditional Korean music stands as a captivating embodiment of artistic *** study embarked on a comprehensive evaluation of a Gugak hall,employing acoustic measurements,computer simulations,and subjective perception *** evaluation focused on the reverberance,clarity,spatial impression,and preference,unravelling the secrets that shape the immersive Gugak *** intricate computer simulations and auralization,the experience of Gugak performances was meticulously brought to life,allowing exploration under diverse conditions by adjusting stage volume ratios from -20% to+20% and modifying the interior materials,including the walls,ceiling,and lateral *** Gugak halls exhibited relatively low values of reverberation time(RT),early decay time(EDT),and binaural quality index(BQI)the dominant factor influencing the acoustic environment was the effect of sound strength(G).Musical clarity(C80)value did not show an inverse proportionality to the reverberation ***,genre differences between traditional Korean and Western classical music did not significantly affect listeners’perception and satisfaction with regards to reverberance,clarity,and spatial *** a result,Gugak halls can adhere to the same acoustic design criteria as Western orchestra halls,since this study found that people perceived them the same *** this study,sound strength was found to be strongly correlated with perception *** was possible to enhance listeners’perception and preference regarding the acoustic environment through material and structural changes to the sidewalls and *** changes improved the reinforcement of low frequencies and simultaneously enhanced the relative effect of side ***,enhancing the reflection and spatial characteristics of the materials effectively improved listener *** on these findings,an optimal des

关键词： Korean traditional hall acoustical parameters perceptual evaluation acoustic preference stage volume ratio

Analytic Formulae for Estimating Motor Proportion of Load Model Under Small Disturbance

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CSEE Journal of Power and Energy Systems 2024年第4期10卷 1599-1607页

作者： ping Ju Shiqiu Xia Yuqing jin Lu Cao School of Electrical and Power Engineering Hohai UniversityNanjing 211100China the East China Branch of the State Grid Corporation of China Shanghai 200120China

In the composite load model(CLM),which is commonly used in China,an equivalent motor and equivalent static load are used to represent all electrical equipment and networks connected to a load *** research has determined typical values of electrical and mechanical parameters for load models of different load types,which improves the basis for load ***,the motor proportion parameter is not the same for different load buses or at different times;therefore,obtaining the actual motor proportion is key to establishing an accurate load *** the existing load modeling method,motor proportion is commonly identified along with other parameters under rare large disturbances;therefore,the value of the motor proportion is fixed by the time when a large disturbance *** this paper,formulae are derived to estimate motor proportion under small disturbances,and these formulae allow direct calculation of motor proportion without using any optimization *** proposed estimation formulae do not rely on any parameters of load model or power system but instead rely only on measurement of the voltage and active power at steady-state points before and after a small *** of universality of small disturbances in power systems,estimating time-varying motor proportion under small disturbances will be helpful for solving the time-varying problem of load ***,the proposed motor proportion estimation formulae are validated by simulations,physical experiments,and field experiments.

关键词： Composite load model load modeling motor proportion parameter estimation

Associations between the use of red yeast rice preparations and adverse health outcomes:An umbrella review of meta-analyses of randomized controlled trials

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Journal of Integrative Medicine 2024年第2期22卷 126-136页

作者： Zhen-yu Ma Shu-ping Yang Ying Li Tian-tian Xu Ya-lin Yang Hui-yong Yang Heng-bing Li Le-jin Zhou yong Diao Su-yun Li School of Medicine Huaqiao UniversityQuanzhou 362021Fujian ProvinceChina College of Traditional Chinese Medicine Shandong University of Traditional Chinese MedicineJinan 250355Shandong ProvinceChina Second Clinical Medical College Nanjing Medical UniversityNanjing 211166Jiangsu ProvinceChina

Background:Red yeast rice(RYR),a natural lipid-lowering agent,is widely used in clinical ***,the existing meta-analyses concerning the safety of RYR preparations have yielded inconsistent results,and the credibility of the evidence has not been ***:This study was designed to evaluate the existing evidence and offer a comprehensive understanding of the associations between the use of RYR preparations and various adverse health *** strategy:Seven literature databases were searched from inception to May 5,2023,using medical subject headings and free-text terms(e.g.,“red yeast rice,”“Xuezhikang,”and“Zhibitai”).Inclusion criteria:Meta-analyses that investigated and quantitatively estimated associations between the use of RYR preparations and adverse health outcomes were included in this *** extraction and analysis:Two researchers independently extracted data using a standardized data collection table;any disagreements were resolved by consulting a third *** on the participant,intervention,comparator and outcome(PICO)framework in each eligible meta-analysis,a series of unique associations between the use of RYR preparations and adverse health outcomes were *** associations’effect estimates were re-evaluated using random-effect ***:Fifteen meta-analyses,comprising 186(164 unique)randomized controlled trials,were *** on A Mea Surement Tool to Assess Systematic Reviews version 2,3(20%)and 12(80%)of these meta-analyses had low and critically low confidence,respectively.A total of 61 unique associations between the use of RYR preparations and adverse health outcomes were extracted from eligible *** on the random-effect models,10(16.4%)associations indicated a significant protective effect of RYR preparations against adverse health outcomes,while 5(8.2%)indicated an increased risk of adverse health outcomes related to uric acid,alanine transaminase and aspartate trans

关键词： Red yeast rice Safety Adverse health outcomes Umbrella review Meta-analysis Systematic review

Oxidation behavior of low-grade vanadiferous titanomagnetite concentrate with high titanium

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Journal of Iron and Steel Research International 2024年第2期31卷 329-341页

作者： jin-sheng Liu Zhen-xing Xing Gong-jin Cheng Xue-yong Ding Xiang-xin Xue School of Metallurgy Northeastern UniversityShenyang110819LiaoningChina Liaoning Key Laboratory of Recycling Science for Metallurgical Resources Shenyang110819LiaoningChina Innovation Research Institute of Vanadium and Titanium Resource Industry Technology Northeastern UniversityShenyang110819LiaoningChina

In order to clarify the oxidation mechanisms and make better use of the low-grade vanadiferous titanomagnetite concentrate with high titanium(LVTC),the oxidation behavior of LVTC was *** results showed that oxidation degree was achieved within 90 min when temperature was not lower than 700°C,and the main phases of the oxidized LVTC consisted of Fe9TiO15,Fe2O3,CaSiTiO5 and a small amount of *** temperature is favorable to the formation of *** surface of LVTC gradually becomes rough,with fine particles of needle-like and granular shape appearing on the surface,which finally turn from laminar to creamy,spread out,and are interspersed with many tiny *** phase oxidation paths in LVTC were as follows:(1)Fe2.75Ti0.25O4→Fe9TiO15+Fe2O3;(2)Fe2.75Ti0.25O4→Fe2O3+FeTiO3→Fe2TiO5;(3)FeTiO3→Fe2O3+Fe2Ti3O9→*** is predominantly mesoporous whether oxidized or not,with the pores mainly distributed in the range of 2–40 nm,and the specific surface area of LVTC decreases significantly with increasing temperature.

关键词： Low-grade vanadiferous titanomagnetite concentrate Oxidation degree Phase transformation Micromorphology Oxidation path Pore structure