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Performances of a Balanced Hydraulic Motor with Planetary Gear Train

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Chinese Journal of Mechanical Engineering 2012年第4期25卷 760-767页

作者： yu Hongying luo Changjie WANG Huimin School of Mechatronics Engineering Harbin Institute of Technology Harbin 150001 China

The current research of a balanced hydraulic motor focuses on the characteristics of the motor with three planet *** of a balanced hydraulic motor with more than three planet gears are hardly *** order to study the characteristics of a balanced hydraulic motor with planetary gear train that includes more than three planet gears,on the basis of analysis of the structure and working principle of a balanced hydraulic motor with planetary gear train,formulas are deduced for calculating the hydraulic motor＇s primary performance indexes such as displacement,unit volume displacement,flowrate fluctuation ratio,*** of the gears＇ tooth number on displacement and flowrate characteristics are *** order to guarantee the reliability of sealing capability,the necessary conditions that tooth number of the sun gear and the planet gears should satisfy are *** large unit volume displacement and small displacement fluctuation ratio as designing objectives,a balanced hydraulic motor with three planet gears and a common gear motor are designed under the conditions of same displacement,tooth addendum coefficien and clearance *** comparing the unit volume displacement and fluctuation ratio of the two motors,it can be seen that the balanced hydraulic motor with planetary gear train has the advantages of smaller fluctuation ratio and larger unit volume *** results provide theoretical basis for choosing gear tooth-number of this kind of hydraulic motor.

关键词： planetary gear mechanism hydraulic motor tooth number selection

Stability analysis method considering non-parallelism:EPSE method and its application

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Applied Mathematics and Mechanics(English Edition) 2016年第1期37卷 27-36页

作者： Gaotong yu Jun GAO jisheng luo Department of Mechanics Tianjin University

The e-N method is widely used in transition prediction. The amplitude growth rate used in the e-N method is usually provided by the linear stability theory （LST） based on the local parallel hypothesis. Considering the non-parallelism effect, the parabolized stability equation （PSE） method lacks local characteristic of stability analysis. In this paper, a local stability analysis method considering non-parallelism is proposed, termed as EPSE since it may be considered as an expansion of the PSE method. The EPSE considers variation of the shape function in the streamwise direction. Its local characteristic is convenient for stability analysis. This paper uses the EPSE in a strong non-parallel flow and mode exchange problem. The results agree well with the PSE and the direct numerical simulation （DNS）. In addition, it is found that the growth rate is related to the normalized method in the non-parallel flow. Different results can be obtained using different normalized methods. Therefore, the normalized method must be consistent.

关键词： parabolized stability equation (PSE) expansion of PSE (EPSE) linear stability theory (LST) normalized method non-parallel

Nusselt number correlation for turbulent heat transfer of helium-xenon gas mixtures

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Nuclear Science and Techniques 2021年第11期32卷 119-133页

作者： Biao Zhou yu ji Jun Sun yu-Liang Sun Institute of Nuclear and New Energy Technology Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of EducationTsinghua UniversityBeijing 100084China

A gas-cooled nuclear reactor combined with a Brayton cycle shows promise as a technology for highpower space nuclear power ***,a helium-xenon gas mixture with a molecular weight of14.5-40.0 g/mol is adopted as the working fluid to reduce the mass and volume of the *** Prandtl number for helium-xenon mixtures with this recommended mixing ratio may be as low as *** the convective heat transfer is closely related to the Prandtl number,different heat transfer correlations are often needed for fluids with various Prandtl *** studies have established heat transfer correlations for fluids with medium-high Prandtl numbers(such as air and water)and extremely lowPrandtl fluids(such as liquid metals);however,these correlations cannot be directly recommended for such helium-xenon mixtures without *** study initially assessed the applicability of existing Nusselt number correlations,finding that the selected correlations are unsuitable for helium-xenon *** establish a more general heat transfer correlation,a theoretical derivation was conducted using the turbulent boundary layer *** simulations of turbulent heat transfer for helium-xenon mixtures were carried out using Ansys *** on simulated results,the parameters in the derived heat transfer correlation are *** is found that calculations using the new correlation were in good agreement with the experimental data,verifying its applicability to the turbulent heat transfer for helium-xenon *** effect of variable gas properties on turbulent heat transfer was also analyzed,and a modified heat transfer correlation with the temperature ratio was *** on the working conditions adopted in this study,the numerical error of the property-variable heat transfer correlation was almost within 10%.

关键词： Gas-cooled nuclear reactor Space nuclear power Helium–xenon mixtures Convective heat transfer Nusselt number

Extension of e^N method to general three-dimensional boundary layers

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Applied Mathematics and Mechanics(English Edition) 2017年第7期38卷 1007-1018页

作者： Lei ZHAO Gaotong yu jisheng luo Department of Mechanics Tianjin University The 41st Institute of No.6 Academy China Aerospace Science & Industry Corporation

In order to extend the eN method to general three-dimensional boundary layers, the conservation law of the imaginary parts for the wave parameters with a fixed wave vector is deduced. The compatibility relationship （CR） and the general theory of ray tracing （RT）, which have been extensively used in conservative systems, are applied to a general three-dimensional boundary layer belonging to non-conservative systems. Two kinds of eN methods, i.e., the eN-CR method and the eN-RT method, are established. Both the two kinds of methods can wavenumber and the amplitude of the be used to predict the evolutions of the spanwise disturbances in general three-dimensional boundary layers. The reliability of the proposed methods is verified and validated by performing a direct numerical simulation （DNS） in a hypersonic general three-dimensional boundary layer over an aircraft model. The results are also compared with those obtained by other eN methods, indicating that the proposed methods have great potential applications in improving the transition prediction accuracy in general three-dimensional boundary layers.

关键词： eN method ray tracing theory transition prediction three-dimensionalboundary layer

Microstructure and properties of Y_2O_3-doped steel-cemented WC prepared by microwave sintering

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Rare Metals 2013年第5期32卷 496-501页

作者： Jun-Ming luo ji-Lin Xu Zhen-Chen Zhong School of Materials Science and Engineering Nanchang Hangkong University

Steel-cemented WC was prepared by ball milling, cold compacting and microwave sintering with Fe powder as the matrix, WC as the hard phase and the addition of rare earth Y2O3. The results show that the interface of the WC particles and Fe matrix exhibits excellent wettability and liquidity when the microwave sintering temperature reaches 1,280℃. The density and mechanical properties of the steel bonded WC carbides could be greatly improved, the hard phases become finer and more uniform dispersed owing to the addition of Y2O3. With the increase of the Y2O3 contents, the grain becomes uniform and fine first, and then gathers and grows up. The relative density, microhardness and bending strength all rise first, reaching the maximum values of 97.29 %, HV1024 and 1,267.60 MPa at 0.5 % Y2O3, respectively, and then decrease. Moreover, the relative density and mechanical properties of the steel-cemented WC with nano-Y2O3 are higher than that with micron-Y2O3, which indicates that the effect of nano-Y2O3 is better than that of the micron-Y2O3.

关键词： Y2O3 content Microwave sintering Steel-cemented WC

Lin yutang＇ s Profound Influence on the Cultural Exchange between China and the West

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学术界 2015年第8期 294-300页

作者： luo yuzhi ji Lingling The English Department of Anhui Agricultural University Hefei Anhui 230036 Shanghai International Studies University Shanghai 200083

Cultural exchange is of great importance to the development of civilization. Lin yutang,a literary giant,not only has significant impact on the development of Chinese modern literature,but also leaves a profound influence on the cultural exchange between China and the West. Lin has received western education since an early age. After reaching adulthood he attains accomplishment in Chinese traditional culture,through which he acquires deep understanding of both cultures. On the one hand,Lin's description of Chinese society and Chinese people,high praise of humorous style,and innovation of translation concept,all contribute considerably to the communication between Chinese and western culture. On the other hand,its negative effect can't be ignored. The false description in his works leaves a deep- rooted cultural prejudice against Chinese in westerners.

关键词：中国传统文化文化交流西方文化林语堂中西文化中国人负效应西方人

Recent progress in synthesis of composite powders and their applications in low-carbon refractories

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Journal of Iron and Steel Research International 2022年第7期29卷 1041-1051页

作者： ji-yuan luo Xin-ming Ren Xiao-chuan Chong Dong-hai Ding Bei-yue Ma Guo-qing Xiao jing-kun yu College of Materials Science and Engineering Xi’an University of Architecture and TechnologyXi’an 710055ShaanxiChina School of Metallurgy Northeastern UniversityShenyang 110819LiaoningChina

The development of low-carbon refractories is of great significance,but it is limited by the deteriorated properties that resulted from the decreased graphite *** composite powders has proved to be effective in improving the properties of low-carbon *** recent progress in the synthesis of composite powders including modified graphite,nanocarbon-containing composite powders,oxide/non-oxide and non-oxide composite powders and their applications in low-carbon refractories were reviewed,and the future development of composite powder technology was prospected.

关键词： Composite powder Modified graphite Nanocarbon-containing composite powder Oxide/non-oxide Non-oxide Low-carbon refractory

Synergistic effect of various elements in Fe_(41)Co_(7)Cr_(15)Mo_(14)C_(15)B_(6)Y_(2) amorphous alloy hollow ball on catalytic degradation of methylene blue

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Journal of Rare Earths 2022年第4期40卷 605-615,I0004页

作者： Wenhu luo Qingjun Chen Li ji Xinyuan Peng Guosheng Huang School of Materials Science and Engineering Nanchang Hongkong UniversityNanchang 330063China State Key Laboratory for Marine Corrosion and Protection Luoyang Ship Material Research Institute(LSMRI)Qingdao 266237China

Metallic glasses have recently attracted great attention in terms of degrading dyes and other organic pollutants as an environmentally friendly material for wastewater ***,we report a new type of amorphous catalyst Fe_(41)Co_(7)Cr_(15)Mo_(14)C_(15)B_(6)Y_(2) hollow *** demonstrate that the catalyst can still completely decolorize the 20 mg/L methylene blue(MB)solution after reused for 50 times under conditions of pH=5,catalyst content 0.5 g/L,and temperature 80°*** catalyst is easily broken during degradation,so the inner surface also provides additional active *** Fe_(41)Co_(7)Cr_(15)Mo_(14)C_(15)B_(6)Y_(2) amorphous alloy hollow balls were characterized by energy dispersive X-ray specroscopy(EDS),scanning electron microscopy(SEM)and X-ray photoelectron spectroscopy(XPS),*** elements in the catalytic system have a synergistic catalytic *** cycle Fe^(2+)/Fe^(3+),Co^(2+)/Co^(3+)and Mo^(4+)/Mo^(6+) promote mutual conversion and accelerate the catalytic process of their reaction with H_(2)O_(2),forming a self-stable redox cycle *** them,Fe^(2+)promotes the conversion of Co^(3+)to Co^(2+),and Mo^(4+) promotes the conversion of Fe^(3+)to Fe^(2+),mainly Fe^(2+)and Co^(2+)react with H_(2)O_(2) to generate•*** and Cr elements form MoO_(2) and Cr_(2)O_(3) plasma compounds on the surface,which act as a protective film to make the catalyst more stable and be repeated used more frequently.

关键词： Metallic glasses Methylene blue degradation Synergistic catalytic Repeatability Hollow ball Rare earths

A methodology for constructing the aircraft design schema

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Chinese Journal of Aeronautics 2023年第8期36卷 148-167页

作者： Xiaojian SUN Mingqiang luo Zhiyang CUI Zhenpeng ji Hu LIU School of Aeronautic Science and Engineering Beihang UniversityBeijing 100191China

Aircraft collaboration design is based on a unified set of schemas containing data and model representations and interfaces across *** aircraft design schema is a central data model that specifies the paradigm for the representation of a full lifecycle model of aircraft *** construction of the schema currently lacks theoretical *** paper designs a novel methodology to construct the aircraft design schema,a fully functional,logical,and selfconsistent *** methodology defines a schema matrix that includes implementation strategies,principles,processes,meta-object facility,views,scenarios,and *** aircraft conceptual design schema is constructed according to the methodology,which is a hands-on approach to help understand the concept and *** features of the methodology are analyzed,and the methodology and the aircraft conceptual design schema are presented to address the pain points of multiple solution trade-offs,multiple iterations,and multidisciplinary coupling in aircraft conceptual collaboration design.

关键词： Aircraftcollaboration design Aircraft design schema Conceptual design Digital engineering Schema construction methodology