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Relativistic transformation between τ and TCG for Mars missions under IAU Resolutions

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Research in Astronomy and Astrophysics 2014年第2期14卷 233-240页

作者： jun-yang pan Yi Xie Department of Astronomy Nanjing University Key Laboratory of Modern Astronomy and Astrophysics Nanjing UniversityMinistry of Education

Considering the fact that the general theory of relativity has become an in- extricable part of deep space missions, we investigate the relativistic transformation between the proper time of an onboard clock τ and the Geocentric Coordinate Time （TCG） for Mars missions. By connecting τ with this local timescale associated with the Earth, we extend previous works which focus on the transformation between τ and the Barycentric Coordinate Time （TCB）. （TCB is the global coordinate time for the whole solar system.） For practical convenience, the relation between τ and TCG is recast to directly depend on quantities which can be read from ephemerides. We find that the difference between τ and TCG can reach the level of about 0.2 seconds in a year. To distinguish various sources in the transformation, we numerically calculate the contributions caused by the Sun, eight planets, three large asteroids and the space- craft. It is found that if the threshold of 1 microsecond is adopted, this transformation must include effects due to the Sun, Venus, the Moon, Mars, Jupiter, Saturn and the velocities of the spacecraft and Earth.

关键词： reference systems -- time -- method: numerical -- space vehicles

Relativistic transformation between τ and TCB for Mars missions: Fourier analysis on its accessibility with clock offset

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Research in Astronomy and Astrophysics 2013年第11期13卷 1358-1362页

作者： jun-yang pan Yi Xie Department of Astronomy Nanjing University Key Laboratory of Modern Astronomy and Astrophysics Nanjing University Ministry of Education

In the context of the fact that Einstein＇s general relativity has become an inevitable part of deep space missions, we will extend previous works on relativistic transformation between the proper time ^- of a clock onboard a spacecraft orbiting Mars and the Barycentric Coordinate Time （TCB） by taking the clock offset into ac- count and investigate its accessibility by Fourier analysis on the residuals after fitting the ^--TCB curve in terms of n-th order polynomials. We find that if the accuracy of a clock can achieve better than ~ 10-5 s or ~ 10-6 s （depending on the type of clock offset） in one year after calibration, the relativistic effects on the difference between 7- and TCB will need to be carefully considered.

关键词： reference systems -- time -- methods: numerical-- space vehicles

Preparation and properties of high-energy-density aluminum/boroncontaining gelled fuels

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Chinese Journal of Chemical Engineering 2024年第1期65卷 230-242页

作者： Yi Chen Kang Xue yang Liu Lun pan Xiangwen Zhang Ji-jun Zou Key Laboratory for Green Chemical Technology of the Ministry of Education School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China Collaborative Innovative Center of Chemical Science and Engineering(Tianjin) Tianjin 300072China Haihe Laboratory of Sustainable Chemical Transformations Tianjin 300192China Zhejiang Institute of Tianjin University Ningbo 315201China

Energetic nanofluid fuel has caught the attention of the field of aerospace liquid propellant for its high energy density(HED), but it suffers from the inevitable solid-liquid phase separation problem. To resolve this problem, herein we synthesized the high-Al-/B-containing(up to 30%(mass)) HED gelled fuels, with low-molecular-mass organic gellant Z, which show high net heat of combustion(NHOC), density, storage stability, and thixotropic properties. The characterizations indicate that the application of energetic particles to the gelled fuels obviously destroys their fibrous network structures but can provide the new particle-gellant gelation microstructures, resulting in the comparable stability between 1.0%(mass) Z/JP-10 + 30%(mass) Al or B and pure JP-10 gelled fuel. Moreover, the gelled fuels with high-content Al or B exhibit high shear-thinning property, recovery capability, and mechanical strength, which are favorable for their storage and utilization. Importantly, the prepared 1.0%(mass) Z/JP-10 + 30%(mass) B(or 1.0%(mass) Z/JP-10 + 30%(mass) Al) shows the density and NHOC 1.27 times(1.30) and 1.43 times(1.21)higher than pure JP-10, respectively. This work provides a facile and valid approach to the manufacturing of HED gelled fuels with high content of energetic particles for gel propellants.

关键词： Gelled fuels Energetic aluminum/boron Low-molecular-mass organic gellant Fuel property

A New Heat Transfer Model for Multi-Gradient Drilling with Hollow Sphere Injection

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Fluid Dynamics & Materials Processing 2024年第3期20卷 537-546页

作者： Jiangshuai Wang Chuchu Cai pan Fu jun Li Hongwei yang Song Deng School of Petroleum and Natural Gas Engineering Changzhou UniversityChangzhouChina CNPC Research Institute of Engineering Technology Co. Ltd.BeijingChina National Engineering Research Center for Oil&Gas Drilling and Completion Technology BeijingChina College of Petroleum Engineering China University of Petroleum(Beijing)BeijingChina College of Petroleum Karamay CampusChina University of Petroleum(Beijing)BeijingChina

Multi-gradient drilling is a new offshore drilling *** accurate calculation of the related wellbore temperature is of great significance for the prediction of the gas hydrate formation area and the precise control of the wellbore *** this study,a new heat transfer model is proposed by which the variable mass flow is properly taken into *** this model,the effects of the main factors influencing the wellbore temperature are *** results indicate that at the position where the separation injection device is installed,the temperature increase of the fluid in the drill pipe is mitigated due to the inflow/outflow of hollow spheres,and the temperature drop of the fluid in the annulus also *** addition,a lower separation efficiency of the device,a shallower installation depth and a smaller circulating displacement tend to increase the temperature near the bottom of the annulus,thereby helping to reduce the hydrate generation area and playing a positive role in the prevention and control of hydrates in deepwater drilling.

关键词： Multi-gradient drilling wellbore temperature hydrate separate injection device variable mass

Effect of Wave Nonlinearity on the Instantaneous Seabed Liquefaction

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China Ocean Engineering 2024年第1期38卷 93-103页

作者： WANG Zhao-jun SUI Ti-ti ZHANG Chi pan jun-ning Key Laboratory of Port Waterway and Sedimentation Engineering of the Ministry of TransportNanjing Hydraulic Research InstituteNanjing 210024China Key Laboratory of Coastal Disaster and Protection(Hohai University) Ministry of EducationNanjing 210098China The National Key Laboratory of Water Disaster Prevention Nanjing 210098China

The nonlinear variation of wave is commonly seen in nearshore area,and the resulting seabed response and liquefaction are of high concern to coastal *** this study,an analytical formula considering the nonlinear wave skewness and asymmetry is adopted to provide wave pressure on the seabed *** liquefaction depth attenuation coefficient and width growth coefficient are defined to quantitatively characterize the nonlinear effect of wave on seabed *** on the 2D full dynamic model of wave-induced seabed response,a detailed parametric study is carried out in order to evaluate the influence of the nonlinear variation of wave loadings on seabed ***,new empirical prediction formulas are proposed to fast predict the maximum liquefaction under nonlinear *** indicate that(1)Due to the influence of wave nonlinearity,the vertical transmission of negative pore water pressure in the seabed is hindered,and therefore,the amplitude decreases significantly.(2)In general,with the increase of wave nonlinearity,the liquefaction depth of seabed decreases *** under asymmetric and skewed wave loading,the attenuation of maximum seabed liquefaction depth is the most significant among all the nonlinear wave ***,highly skewed wave can cause the liquefaction depth of seabed greater than that under linear wave.(3)The asymmetry of wave pressure leads to the increase of liquefaction width,whereas the influence of skewedness is not significant.(4)Compared with the nonlinear waveform,seabed liquefaction is more sensitive to the variation of nonlinear degree of wave loading.

关键词： nonlinear wave seabed response seabed liquefaction numerical simulation liquefaction prediction

Performance and enhanced oil recovery efficiency of an acid-resistant polymer microspheres of anti-CO2 channeling in low-permeability reservoirs

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Petroleum Science 2024年第4期21卷 2420-2432页

作者： Hai-Zhuang Jiang Hong-Bin yang Ruo-Sheng pan Zhen-Yu Ren Wan-Li Kang jun-Yi Zhang Shi-Long pan Bauyrzhan Sarsenbekuly State Key Laboratory of Deep Oil and Gas China University of Petroleum (East China) School of Petroleum Engineering China University of Petroleum (East China) Oil and Gas Engineering Research Institute School of Energy and Petroleum Industry Kazakh-British Technical University

CO2flooding is a vital development method for enhanced oil recovery in low-permeability reservoirs,However,micro-fractures are developed in low-permeability reservoirs,which are essential oil flow channels but can also cause severe CO2gas channeling ***,anti-gas channeling is a necessary measure to improve the effect of *** kind of anti-gas channeling refers to the plugging of fractures in the deep formation to prevent CO2gas channeling,which is different from the wellbore *** microspheres have the characteristics of controllable deep plugging,which can achieve the profile control of low-permeability fractured *** acidic environments with supercritical CO2,traditional polymer microspheres have poor expandability and plugging *** on previous work,a systematic evaluation of the expansion performance,dispersion rheological properties,stability,deep migration,anti-CO2channeling and enhanced oil recovery ability of a novel acid-resistant polymer microsphere（DCNPM-A） was carried out under CQ oilifield conditions（salinity of85,000 mg/L,80℃,pH=3）.The results show that the DCNPM-A microsphere had a better expansion performance than the traditional microsphere,with a swelling rate of *** microsphere dispersion with a concentration of 0.1%-0.5% had the advantages of low viscosity,high dispersion and good injectability in the low permeability fractured *** the acidic environment of supercritical CO2,DCNPM-A microspheres showed excellent stability and could maintain strength for over 60 d with less *** core experiments,DCNPM-A microspheres exhibited delayed swelling characteristics and could effectively plug deep *** a plugging rate of 95%,the subsequent enhanced oil recovery of CO2flooding could reach 21.03%.The experimental results can provide a theoretical basis for anti-CO2channeling and enhanced oil recovery in low-permeability fractured reservoirs.

关键词： Low-permeability reservoir Anti-CO 2 channeling Polymer microsphere Acid resistance

Aging Behavior of As-Extruded Ti Particles Reinforced VW94 Composites

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Acta Metallurgica Sinica(English Letters) 2024年第3期37卷 401-406页

作者： Dongmei Pu Xianhua Chen Jingfeng Wang jun Tan Jianbo Li Hong yang Bo Feng Kaihong Zheng Fusheng pan College of Materials Science and Engineering Chongqing UniversityChongqing 400045China National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400045China Institute of New Materials Guangdong Academy of SciencesGuangzhou 510650China

The ageing behavior of as-extruded Ti_(P)/VW94 composites was *** peak hardness of the composites increases compared to the matrix alloy and the 5%Ti_(P)/VW94 composite presents the highest peak hardness of 148.7 HV after aging for about 50 ***,the hardness increments first decrease and then slightly increase with increasing Ti particle content due to the introduction of high-density dislocations by Ti particles.

关键词： Magnesium matrix composites Ti particles Ageing behavior Hardness

A compact route for efficient production of high-purity β-Ga2O3 powder

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Rare Metals 2024年第9期43卷 4573-4584页

作者： Xiao-Wei Zhou Gao-Jie Chen Liang Xu Zhi-jun Shao Cheng yang Yong-pan Tian Zhuo Zhao School of Metallurgical Engineering Anhui University of Technology Low-Carbon Research Institute Anhui University of Technology

The present study has proposed a compact process for the production of high-purity β-Ga2O3powder by simply using gallium metal and water as the raw materials. The process basically consists of two essential steps including hydrothermal synthesis of Ga OOH and calcination of Ga OOH for the production of the target product of β-Ga2O3. Thermodynamic evaluation and systematic experiments were conducted for process parameter optimization. X-ray diffractometer（XRD）, scanning electron microscopy（SEM）, thermogravimetryDdifferential scanning calorimetry（TG-DSC） and X-ray photoelectron spectroscopy（XPS） were utilized to clarify the reaction mechanisms of the hydrothermal synthesis and transformation of Ga OOH to β-Ga2O3by calcination. Chemical analysis of the final product of β-Ga2O3obtained under the optimal conditions was carried out with inductively coupled plasma mass spectrometry（ICP-MS）, and the results showed that the contents of the representative impurities such as Ni, Cu, In, Mn, Co, Zn and Cr are obviously lower than the requirement of 5N β-Ga2O3standard, exhibiting excellent application prospect of the proposed process to produce high-purity β-Ga2O3.

关键词： Calcination Hydrothermal synthesis Purity Reaction mechanism β-Ga2O3

Effect of V on high-temperature mechanical properties of Al-5Cu-1.5Ni alloy

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Journal of Iron and Steel Research International 2024年第7期31卷 1792-1810页

作者： jun-ge Cui Yong-bin Chen Xiang-zhou Fu Hai-long yang Han-zhang Wang An-min Li Li-wen pan School of Resources Environment and MaterialsGuangxi UniversityNanning 530004GuangxiChina State Key Laboratory of Featured Metal Materials and Life-Cycle Safety for Composite Structures Nanning 530004GuangxiChina Guangxi Higher Education Key Laboratory of Advanced Materials Nanning 530004GuangxiChina

The effects of V on microstructure,room temperature,and high-temperature(350℃)mechanical properties of Al-5Cu-1.5Ni alloy were *** results show that Al-5Cu-1.5Ni-xV alloys mainly compriseα-Al,Al_(2)Cu,Al_(3)(Ni,Cu)_(2),Al_(3)Ni,Al7Cu4Ni,and Al_(10)V *** addition of V can signally refineα-Al dendritic structure,which improves the mechanical properties of the as-cast alloys at room and high *** T6 heat treatment(540℃/12 h/WC+170℃/8 h/AC),α-Al,network skeleton structure Al_(3)(Ni,Cu)_(2),and Al_(10)V phases all show coarsening,while the fine nano-θ'-Al_(2)Cu precipitated from the matrix and dispersed *** introduction of V promotes the quantity of precipitatedθ'-Al_(2)Cu *** ultimate tensile strength of the heat-treated alloys at room and high temperatures is greatly improved compared to that of the as-cast *** highest high-temperature ultimate tensile strength of the alloys with V is 111.8 MPa,21.5%higher than that of the base *** analysis shows that the improvement of high-temperature mechanical properties after heat treatment is mainly due to the introduction of V,increasing the precipitated quantity of nano-θ'-Al_(2)Cu particles and improving its thermal *** dispersion strengthening effect ofθ'-Al_(2)Cu particles exceeds the weakening effect of other adverse microstructures on the mechanical properties.

关键词： Al-Cu-Ni-V alloy θ'-Al_(2)Cu phase Heat treatment Microstructure Mechanical property