检索结果-南通市图书馆

Evolution of inclusions in vacuum induction melting of superalloys containing 70%return material

Journal of Iron and Steel Research(International) 2024年第3期31卷 719-728页

作者： Jin-guo gao shu-lei Yang shu-feng Yang Jing-she Li Wei Liu Meng-jing Zhao An-ren Wang School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China Metallurgical and Building Materials Business Department China International Engineering Consulting CorporationBeijing 100048China

The variation law of inclusions type and size in the vacuum induction melting process and ingot of Ni-based superalloy containing 70%return material was studied by industrial test sampling,and the mechanism of inclusions formation was analyzed with thermodynamic calculations.The results show that there are mainly two types of composite inclusions in the vacuum induction melting of Ni-based superalloys,which are nitride-and oxide-based composite inclusions,like Al_(2)O_(3)-SiO_(2)-Cr_(2)O_(3),TiN-(Mo,Nb)C,etc.The type and proportion of inclusions from the center to the edge of the vacuum induction ingot did not change significantly.The number density of inclusions from the center to the edge of the ingot varied less,and the size of inclusions became smaller from the center to the edge.In addition,thermodynamic calculations show that oxides(M_(2)O_(3))are present in the liquid phase and mainly contain Al,Ti,Cr,Fe and O elements.The nitride consists mainly of Ti and N and contains small amounts of Cr,C,Nb,and Mo elements.This is consistent with the results of industrial tests.As the temperature decreases,the precipitation phases such as M_(2)O_(3),MN,γ,MC,δ,γ'andμphases are gradually precipitated,where oxides and nitrides are present in the liquid phase.The contents of O and N elements are the main influencing factors for the inclusions content and precipitation temperature;when the nitrogen content is reduced to below 0.0015%,it can make MN precipitate below the liquid-phase line.

关键词： Ni-based superalloy Vacuum induction melting Return material Inclusion Thermodynamic

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Asymptotic normality of error density estimator in stationary and explosive autoregressive models

引用

Applied Mathematics(A Journal of Chinese Universities) 2024年第1期39卷 140-158页

作者： WU Shi-peng YANG Wen-zhi gao Min HU shu-he School of Mathematical Sciences&School of Big Data and Statistics Anhui UniversityHefei 230601China School of Statistics Shanxi University of Finance and EconomicsTaiyuan030006China

In this paper,we consider the limit distribution of the error density function estima-tor in the rst-order autoregressive models with negatively associated and positively associated random errors.Under mild regularity assumptions,some asymptotic normality results of the residual density estimator are obtained when the autoregressive models are stationary process and explosive process.In order to illustrate these results,some simulations such as con dence intervals and mean integrated square errors are provided in this paper.It shows that the residual density estimator can replace the density\estimator"which contains errors.

关键词： explosive autoregressive models residual density estimator asymptotic distribution association sequence

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Aerodynamic/stealth design of S-duct inlet based on discrete adjoint method

引用

Applied Mathematics and Mechanics(English Edition) 2024年第4期45卷 725-746页

作者： Jun DENG Ke ZHAO Lin ZHOU Wei ZHANG Bowen shu Jiangtao HUANG Zhenghong gao School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China Aerospace Technology Institute of China Aerodynamic Research and Development CenterMianyang 621000Sichuan ProvinceChina

It is a major challenge for the airframe-inlet design of modern combat aircrafts,as the flow and electromagnetic wave propagation in the inlet of stealth aircraft are very complex.In this study,an aerodynamic/stealth optimization design method for an S-duct inlet is proposed.The upwind scheme is introduced to the aerodynamic adjoint equation to resolve the shock wave and flow separation.The multilevel fast multipole algorithm(MLFMA)is utilized for the stealth adjoint equation.A dorsal S-duct inlet of flying wing layout is optimized to improve the aerodynamic and stealth characteristics.Both the aerodynamic and stealth characteristics of the inlet are effectively improved.Finally,the optimization results are analyzed,and it shows that the main contradiction between aerodynamic characteristics and stealth characteristics is the centerline and crosssectional area.The S-duct is smoothed,and the cross-sectional area is increased to improve the aerodynamic characteristics,while it is completely opposite for the stealth design.The radar cross section(RCS)is reduced by phase cancelation for low frequency conditions.The method is suitable for the aerodynamic/stealth design of the aircraft airframe-inlet system.

关键词： S-duct inlet aerodynamic/stealth optimization design discrete adjoint upwind scheme multilevel fast multipole algorithm(MLFMA)

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effect of multiple coulomb scattering on the beam tests of silicon pixel detectors

引用

Nuclear Science and Techniques 2024年第4期35卷 200-207页

作者： Lan-Kun Li Ming-Yi Dong Ze gao Liang-Cheng-Long Jin shu-Jun Zhao School of Physics and Microelectronics Zhengzhou UniversityZhengzhou 450001China State Key Laboratory of Particle Detection and Electronics(Institute of High Energy Physics CAS)Beijing 100049China University of Chinese Academy of Science Beijing 100049China University of South China Hengyang 421001China

In the research and development of new silicon pixel detectors,a collimated monoenergetic charged-particle test beam equipped with a high-resolution pixel-beam telescope is crucial for prototype verification and performance evaluation.When the beam energy is low,the effect of multiple Coulomb scattering on the measured resolution of the Device Under Test(DUT)must be considered to accurately evaluate the performance of the pixel chips and detectors.This study aimed to investigate the effect of multiple Coulomb scattering on the measured resolution,particularly at low beam energies.Simulations were conducted using Allpix^(2) to study the effects of multiple Coulomb scattering under different beam energies,material budgets,and telescope layouts.The simulations also provided the minimum energy at which the effect of multiple Coulomb scattering could be ignored.Compared with the results of a five-layer detector system tested with an electron beam at DESY,the simulation results were consistent with the beam test results,confirming the reliability of the simulations.

关键词： Silicon Pixel Detectors Beam Telescope Multiple Coulomb Scattering Spatial Resolution

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Desired Dynamic Equation for Primary Frequency Modulation Control of Gas Turbines

引用

Energy Engineering 2024年第5期121卷 1347-1361页

作者： Aimin gao Xiaobo Cui Guoqiang Yu Jianjun shu Tianhai Zhang Thermal Power Center Jiangsu Frontier Electric Technology Co.Ltd.Nanjing211102China School of Energy and Power Engineering Nanjing Institute of TechnologyNanjing211167China

Gas turbines play core roles in clean energy supply and the construction of comprehensive energy systems.The control performance of primary frequency modulation of gas turbines has a great impact on the frequency control of the power grid.However,there are some control difficulties in the primary frequency modulation control of gas turbines,such as the coupling effect of the fuel control loop and speed control loop,slow tracking speed,and so on.To relieve the abovementioned difficulties,a control strategy based on the desired dynamic equation proportional integral(DDE-PI)is proposed in this paper.Based on the parameter stability region,a parameter tuning procedure is summarized.Simulation is carried out to address the ease of use and simplicity of the proposed tuning method.Finally,DDE-PI is applied to the primary frequency modulation system of an MS6001B heavy-duty gas turbine.The simulation results indicate that the gas turbine with the proposed strategy can obtain the best control performance with a strong ability to deal with system uncertainties.The proposed method shows good engineering application potential.

关键词： Gas turbine primary frequency modulation(PFM) desired dynamic equation(DDE) proportion-integral(PI)

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Aero-Hydro-Elastic-Servo Modeling and Dynamic Response Analysis of A Monopile Offshore Wind Turbine Under Different Operating Scenarios

引用

China Ocean Engineering 2024年第3期38卷 379-393页

作者： XIE shuang-yi gao Jian LI Yong-ran JIANG shu-xin ZHANG Cheng-lin HE Jiao College of Mechanical Engineering Chongqing University of TechnologyChongqing 400044China Beijing Institute of Precision Mechatronics and Controls Beijing 100076China College of Mechanical and Vehicle Engineering Chongqing UniversityChongqing 400044China Fishery Machinery and Instrument Research Institute Chinese Academy of Fishery SciencesShanghai 200092China School of Mechanical and Power Engineering Chongqing University of Science&TechnologyChongqing 401331China

This paper constructs a coupled aero-hydro-elastic-servo simulation framework for a monopile offshore wind turbine(OWT).In this framework,a detailed multi-body dynamics model of the monopile OWT including the gearbox,blades,tower and other components(nacelle,hub,bedplate,etc.)has been explicitly established.The effects of pile−soil interaction,controller and operational conditions on the turbine dynamic responses are studied systematically in time domain and frequency domain.The results show that(1)a comprehensive drivetrain model has the capability to provide a more precise representation of the complex dynamic characteristics exhibited by drivetrain components,which can be used as the basis for further study on the dynamic characteristics of the drivetrain.(2)The pile−soil interaction can influence the wind turbine dynamic responses,particularly under the parked condition.(3)The effect of the pile−soil interaction on tower responses is more significant than that on blade responses.(4)The use of the controller can substantially affect the rotor characteristics,which in turn influences the turbine dynamic responses.(5)The tower and blade displacements under the operational condition are much larger than those under the parked condition.The model and methodology presented in this study demonstrate potential for examining complex dynamic behaviors of the monopile OWTs.To ensure accuracy and precision,it is imperative to construct a detailed model of the wind turbine system,while also taking into account simulation efficiency.

关键词： offshore wind turbine(OWT) pile−soil interaction dynamic response parked condition operating condition

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Anti-osteosarcoma trimodal synergistic therapy using NiFe-LDH and MXene nanocomposite for enhanced biocompatibility and efficacy

引用

Acta Pharmaceutica Sinica B 2024年第3期14卷 1329-1344页

作者： Yani Xu Lan Yang Min Li Haozhou shu Na Jia Yunzhen gao Rongying Shi Xiaojia Yang Zhirong Zhang Ling Zhang Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry West China School of PharmacySichuan UniversityChengdu 610041China Med-X Center for Materials College of Polymer Science and EngineeringSichuan UniversityChengdu 610065China

Osteosarcoma is usually resistant to immunotherapy and,thus primarily relies on surgical resection and high-dosage chemotherapy.Unfortunately,less invasive or toxic therapies such as photothermal therapy(PTT)and chemodynamic therapy(CDT)generally failed to show satisfactory outcomes.Adequate multimodal therapies with proper safety profiles may provide better solutions for osteosarcoma.Herein,a simple nanocomposite that synergistically combines CDT,PTT,and chemotherapy for osteosarcoma treatment was fabricated.In this composite,small 2D Ni Fe-LDH flakes were processed into 3D hollow nanospheres via template methods to encapsulate 5-Fluorouracil(5-FU)with high loading capacity.The nanospheres were then adsorbed onto larger 2D Ti3C2MXene monolayers and finally shielded by bovine serum albumin(BSA)to form 5-FU@Ni Fe-LDH/Ti3C2/BSA nanoplatforms(5NiTiB).Both in vitro and in vivo data demonstrated that the 5-FU induced chemotherapy,Ni Fe-LDH driven chemodynamic effects,and MXene-based photothermal killing collectively exhibited a synergistic“all-in-one”anti-tumor effect.5NiTiB improved tumor suppression rate from<5%by 5-FU alone to~80.1%.This nanotherapeutic platform achieved higher therapeutic efficacy with a lower agent dose,thereby minimizing side effects.Moreover,the composite is simple to produce,enabling the fine-tuning of dosages to suit different requirements.Thus,the platform is versatile and efficient,with potential for further development.

关键词： Osteosarcoma NiFe-LDH MXene Chemodynamic therapy Photothermal therapy Chemotherapy 5-Fluorouracil Nanocomposite

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Groundwater Quality and Vulnerability Assessment in a Semiarid Karst Region of Northern China

引用

Journal of Earth Science 2024年第1期35卷 313-316页

作者： Ran An shu Wang Zongjun gao Zhenyan Wang Wei Li Qijun Deng Lü Lin Yuanqing Liu Key Laboratory of Water Cycle and Related Land Surface Processes Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China Shandong University of Science and Technology Qingdao 266510China Center for Hydrogeology and Environmental Geology Survey China Geological SurveyBaoding 071051China

Groundwater plays a critical role in maintaining ecological balance and ensuring social operations,especially in arid and semiarid regions(Hu et al.,2023;Han et al.,2022;Ma et al.,2014).The over-exploitation of groundwater,coupled with the influx of pollutants from human activities into the soil,significantly degrades the environment in certain regions(Jia et al.,2019;Famiglietti,2014;Giordano,2009;Konikow and Kendy,2005;Bohlke,2002;Shah et al.,2000).

关键词： groundwater Groundwater Vul

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Sequential pyrolysis for understanding specific influence of cellulose- and lignin-derived volatiles on properties of counterpart char

引用

Green Chemical Engineering 2024年第2期5卷 222-235页

作者： Yuewen Shao Chao Li Mengjiao Fan Guoming gao Stelgen Inkoua Lijun Zhang shu Zhang Jun Xiang Song Hu Xun Hu School of Material Science and Engineering University of JinanJinan250022China Joint International Research Laboratory of Biomass Energy and Materials College of Materials Science and EngineeringNanjing Forestry UniversityNanjing210037China State Key Laboratory of Coal Combustion Huazhong University of Science and Technology430074China

Interactions of cellulose-and lignin-derived intermediates have been well documented during pyrolysis of lignocellulosic biomass.The reaction network for the interactions is rather complex,as cellulose-derived volatiles could interact/react with not only lignin-derived volatiles but also lignin-derived char and vice versa.To probe specifically the impacts of cellulose-derived volatiles on the lignin-derived char or the opposite,herein the sequential pyrolysis was performed by arranging cellulose in the upper bed with lignin in the lower bed or lignin above with cellulose below at 350 and 650℃,respectively.The results indicated that the sequential pyrolysis of cellulose→lignin or lignin→cellulose at 350℃induced increased char yield from formation of carbonaceous deposits via volatiles-char interactions.Compared with the lignin-derived volatiles,the cellulose-derived volatiles,especially aldehyde fractions,were more reactive towards the lignin-derived char at 350℃,forming oxygen-rich lignin-derived char with a higher yield,an abundance of aliphatic structures and consequently lower thermal stability.In sequential pyrolysis of lignin→cellulose,more aromatics-rich species were deposited on cellulose-derived char,but the lignin-derived volatiles were less reactive for enhancing the char yield.At 650℃,instead of polymerisation of the volatiles on the char,either the cellulose-or lignin-derived char catalyzed the cracking of the counterpart volatiles to remove the aliphatic functionalities,which made the char more aromatic and thermally more stable.

关键词： Cellulose Lignin Sequential pyrolysis Char Interaction

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Parameter calibration of the tensile-shear interactive damage constitutive model for sandstone failure

引用

Journal of Rock Mechanics and Geotechnical Engineering 2024年第4期16卷 1153-1174页

作者： Yun shu Zheming Zhu Meng Wang Weiting gao Fei Wang Duanying Wan Yuntao Wang MOE Key Laboratory of Deep Earth Science and Engineering College of Architecture and EnvironmentSichuan UniversityChengdu610065China Failure Mechanics and Engineering Disaster Prevention Key Laboratory of Sichuan ProvinceSichuan UniversityChengdu610065China Tianfu Engineering-oriented Numerical Simulation & Software Innovation Center Chengdu620107China

The tensile-shear interactive damage(TSID)model is a novel and powerful constitutive model for rock-like materials.This study proposes a methodology to calibrate the TSID model parameters to simulate sandstone.The basic parameters of sandstone are determined through a series of static and dynamic tests,including uniaxial compression,Brazilian disc,triaxial compression under varying confining pressures,hydrostatic compression,and dynamic compression and tensile tests with a split Hopkinson pressure bar.Based on the sandstone test results from this study and previous research,a step-by-step procedure for parameter calibration is outlined,which accounts for the categories of the strength surface,equation of state(EOS),strain rate effect,and damage.The calibrated parameters are verified through numerical tests that correspond to the experimental loading conditions.Consistency between numerical results and experimental data indicates the precision and reliability of the calibrated parameters.The methodology presented in this study is scientifically sound,straightforward,and essential for improving the TSID model.Furthermore,it has the potential to contribute to other rock constitutive models,particularly new user-defined models.

关键词： Damage constitutive model Parameter calibration Rock modeling Sandstone Dynamic impact load Tensile-shear interactive damage(TSID)model

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：