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Chatter stability and precision during high-speed ultrasonic vibration cutting of a thin-walled titanium cylinder

Chinese Journal of Aeronautics 2020年第12期33卷 3535-3549页

作者： Zhenlong PENG Deyuan zhang xiangyu zhang School of Mechanical Engineering and Automation Beihang UniversityBeijing 100083China Institute of Bionic and Micro-Nano Systems Beihang UniversityBeijing 100083China Beijing Advanced Innovation Center for Biomedical Engineering Beihang UniversityBeijing 100083China

Titanium alloys are widely used in the aviation and aerospace industries due to their unique mechanical and physical ***,thin-walled titanium(Ti)cylinders have received increasing attention for their applications as rocket engine casings,aircraft landing gear,and aero-engine hollow shaft due to their observed improvement in the thrust-to-weight ***,the conventional cutting(CC)process is not appropriate for thin-walled Ti cylinders due to its low thermal conductivity,high strength,and low ***,high-speed ultrasonic vibration cutting(HUVC)assisted processing has recently proved highly effective for Ti-alloy *** this study,HUVC technology is employed to perform external turning of a thinwalled Ti cylinder,which represents a new application of ***,the kinematics,tool path,and dynamic cutting thickness of HUVC are ***,the phenomenon of mode-coupling chatter is analyzed to determine the effects and mechanism of HUVC by establishing a critical cutting thickness *** can increase the critical cutting thickness and effectively reduce the average cutting force,thus reducing the energy intake of the ***,comparison experiments are conducted between HUVC and CC *** results indicate that the diameter error rate is 10%or less for HUVC and 51%for the CC method due to a 40%reduction in the cutting *** addition,higher machining precision and better surface roughness are achieved during thin-walled Ti cylinder manufacturing using HUVC.

关键词： High-speed machining Minimum chip thickness Mode-coupling Thin-walled cylinder Ultrasonic vibration cutting

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Tangent-impulse transfer from elliptic orbit to an excess velocity vector

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Chinese Journal of Aeronautics 2014年第3期27卷 577-583页

作者： zhang Gang zhang xiangyu Cao Xibin Research Center of Satellite Technology Harbin Institute of Technology National and Local United Engineering Research Center of Small Satellite Technology

The two-body orbital transfer problem from an elliptic parking orbit to an excess veloc-ity vector with the tangent impulse is studied. The direction of the impulse is constrained to be aligned with the velocity vector, then speed changes are enough to nullify the relative velocity. First, if one tangent impulse is used, the transfer orbit is obtained by solving a single-variable function about the true anomaly of the initial orbit. For the initial circular orbit, the closed-form solution is derived. For the initial elliptic orbit, the discontinuous point is solved, then the initial true anomaly is obtained by a numerical iterative approach; moreover, an alternative method is proposed to avoid the singularity. There is only one solution for one-tangent-impulse escape trajectory. Then, based on the one-tangent-impulse solution, the minimum-energy multi-tangent-impulse escape trajectory is obtained by a numerical optimization algorithm, e.g., the genetic method. Finally, several examples are provided to validate the proposed method. The numerical results show that the minimum-energy multi-tangent-impulse escape trajectory is the same as the one-tangent-impulse trajectory.

关键词： Elliptic orbit Escape trajectory Excess velocity vector Orbital transfer Tangent impulse

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Interactions between cancer cells and bone microenvironment promote bone metastasis in prostate cancer

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Cancer Communications 2019年第1期39卷 645-654页

作者： xiangyu zhang Department of Pathology Jining First People’s HospitalJining Medical UniversityNo.6 Jiankang RoadJining 272000ShandongP.R.China

Bone metastasis is the leading cause of death in prostate cancer patients,for which there is currently no effective *** the bone microenvironment plays an important role in this process,attentions have been directed to the interactions between cancer cells and the bone microenvironment,including osteoclasts,osteoblasts,and bone stromal ***,we explained the mechanism of interactions between prostate cancer cells and metastasis-associated cells within the bone microenvironment and further discussed the recent advances in targeted therapy of prostate cancer bone *** review also summarized the effects of bone microenvironment on prostate cancer metastasis and the related mechanisms,and provides insights for future prostate cancer metastasis studies.

关键词： Prostate cancer Bone metastasis Bone microenvironment Colonization Dormancy Reactivation Reconstruction Nuclear factor-κB ligand Androgen receptor Targeted therapy

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Effect of biased estimation on radar-to-ESM track association

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Journal of Systems Engineering and Electronics 2012年第2期23卷 188-194页

作者： Guohong Wang xiangyu zhang Shuncheng Tan Institute of Information Fusion Naval Aeronautical and Astronautical UniversityYantai 264001R R.China

The track association problem of radar and electronic support measure （ESM） has been considered in the literature for several years. This problem is crucial for radar-to-ESM track fusion and is complicated by the presence of individual systematic errors and measurement errors. In order to improve the track association of radar and ESM sensors, a pseudo-linear filtering algorithm is proposed to estimate the target states and improve the stability of the filter. It is found that, however, the correct probability of radar- to-ESM track association decreases as the radar measurement error decreases, when the pseudo-linear filter is used for ESM sensor filtering. In view of the strange phenomenon, this paper analyzes the reason for it by using the statistic theory and further performs Monte Carlo simulation to verify the analysis.

关键词： radar electronic support measure (ESM) track asso- ciation bias.

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The Dilemma in the Judicial Determination of Justifiable Defense and Its Solution

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学术界 2020年第10期 225-233页

作者： zhang xiangyu Law School Beijing Normal University Beijing 100875

When important social rights and interests of any citizens cannot be protected by public power in time,they can adopt extreme means to protect personal interests from infringement by criminal ***,in judicial practice,some defensive behavior maintaining personal legal rights and interests,even some brave acts for a just cause,are deemed to be over defense or intentional *** at the actual situation of judicial practice in China,the number of cases identified as justifiable defense is even *** the face of such judicial dilemma,scientific judicial concept shall be established in the judicial practice so as to accurately explain and apply to the provisions of laws and judicial interpretations related to justifiable *** formation of authoritative cases,interpret the constitution conditions of justifiable defense,form binding judicial rules and strictly distinguish between justifiable defense,excessive defense and intentional crime so as to restrain subsequent similar cases.

关键词： Justifiable defense judicial practice dilemma solution

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A hypersonic target coherent integration detection algorithm based on Doppler feedback

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Journal of Systems Engineering and Electronics 2020年第1期31卷 85-94页

作者： LI Lin WANG Guohong SUN Dianxing zhang xiangyu Institute of Information Fusion Naval Aviation UniversityYantai 264001China College of Electronic Science National University of Defense TechnologyChangsha 410073China

The traversal search of multi-dimensional parameter during the process of hypersonic target echo signal coherent integration,leads to the problem of large amounts of calculation and poor real-time *** view of these problems,a modified polynomial Radon-polynomial Fourier transform(MPRPFT)hypersonic target coherent integration detection algorithm based on Doppler feedback is proposed in this ***,the Doppler estimation value of the target is obtained by using the target point information obtained by subsequent non-coherent integration ***,the feedback adjustment of the coherent integration process is performed by using the acquired target Doppler estimation ***,the coherent integration is completed after adjusting the search interval of *** simulation results show that the algorithm can effectively reduce the computational complexity and improve the real-time performance on the basis of the effective coherent integration of hypersonic target echo signals.

关键词： hypersonic target coherent integration non-coherent integration Doppler estimation feedback adjustment

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Challenges and opportunities of machine learning control in building operations

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Building Simulation 2023年第6期16卷 831-852页

作者： Liang zhang Zhelun Chen xiangyu zhang Amanda Pertzborn Xin Jin The University of Arizona 1209 E 2nd StTucsonAZUSA Drexel University 3141 Chestnut StPhiladelphiaPAUSA National Renewable Energy Laboratory 15013 Denver W PkwyGoldenCOUSA National Institute of Standards and Technology 100 Bureau DrGaithersburgMDUSA

Machine learning control(MLC)is a highly flexible and adaptable method that enables the design,modeling,tuning,and maintenance of building controllers to be more accurate,automated,flexible,and *** research topic of MLC in building energy systems is developing rapidly,but to our knowledge,no review has been published that specifically and systematically focuses on MLC for building energy *** paper provides a systematic review of MLC in building energy *** review technical papers in two major categories of applications of machine learning in building control:(1)building system and component modeling for control,and(2)control process *** identify MLC topics that have been well-studied and those that need further research in the field of building operation *** also identify the gaps between the present and future application of MLC and predict future trends and opportunities.

关键词： machine learning building operation control building energy system reinforcement learning

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Regulation of TiO_(2) nanoarrays on titanium implants for enhanced osteogenic activity and immunomodulation

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Journal of Materials Science & Technology 2023年第19期150卷 233-244页

作者： Ruoyu Li Hongyu zhang Xiaohong Yao Bin Tang Paul K Chu xiangyu zhang Shanxi Key Laboratory of Biomedical Metal Materials College of Materials Science and EngineeringTaiyuan University of TechnologyTaiyuan 030024China Department of Occupational Disease Second Hospital of Shanxi Medical UniversityTaiyuan 030001China Department of Physics Department of Materials Science and Engineeringand Department of Biomedical EngineeringCity University of Hong KongTat Chee AvenueKowloonHong KongChina College of Biomedical Engineering Taiyuan University of TechnologyTaiyuan 030024China

The surface topography of implants plays a major role in osteogenesis and *** this study,three types of TiO_(2) nanoarrays including nanorod arrays with a diameter of 45 nm(TiO_(2)-N),nanorod arrays with a diameter of 60 nm(TiO_(2)-N N),and nanocone arrays(TiO_(2)-NW)are prepared on titanium and the behavior of bone marrow stromal cells(BMSCs)and polarization of macrophages are *** to the planar titanium control,TiO_(2) nanoarrays facilitate osteogenesis of BMSCs and stimulate the pro-healing M2 ***,adhesion,spreading,proliferation,and osteogenic differentiation of BMSCs are more pronounced on TiO_(2)-N N than both TiO_(2)-N and TiO_(2)-***_(2)-NN also produces the best immune microenvironment,while TiO_(2)-NW is more favorable than TiO_(2)-NN from the viewpoint of cell adhesion and spreading of osteoblasts.

关键词： TiO_(2)nanoarrays Osteogenic activity Immunomodulation Hydrothermal treatment

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Development of L-arginine-based poly(ester urethane)urea for enhanced vascular adaptability

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Science China(Technological Sciences) 2022年第11期65卷 2751-2762页

作者： BAI Shan zhang xiangyu ZANG LeiLei REN LiXia YUAN XiaoYan School of Materials Science and Engineering Tianjin Key Laboratory of Composite and Functional MaterialsTianjin UniversityTianjin300350China

Mismatched biomechanical properties between artificial vascular grafts and native blood vessels can result in intimal hyperplasia,especially for the implantation of small-diameter blood *** biomaterials for vascular repair still remain *** poly(ε-caprolactone)(PCL)has been applied for the preparation of electrospun vascular grafts,but more efforts are needed to improve its compliance with tissue ***,L-arginine-based poly(ester urethane)urea(PEUU)with both elasticity and biodegradability was synthesized so as to enhance the biomechanical properties of vascular grafts by blending electrospinning with PCL in a given mass *** was exhibited that the prepared electrospun PCL/PEUU fibrous membranes were suitable for cell proliferation with normal cell *** importantly,the electrospun membrane with 1/1 mass ratio of PCL/PEUU(PEUU50)showed specific flexibility,exhibiting more suitable mechanical properties matching to the native blood ***,the PEUU50 electrospun membrane demonstrated significantly lower Young’s modulus(9.3±0.8 MPa)and tensile strength(6.0±0.5 MPa),and extremely higher elongation(389%±24%)in wet state than those(16.3±3.0 MPa,11.4±7.1 MPa and 196%±57%,respectively)of the pristine PCL ***,this study demonstrated the great potential of amino acid-based PEUUs for the application in small-diameter vascular grafts.

关键词： poly(ester urethane)urea poly(e-caprolactone) electrospinning vascular grafts mechanical properties

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Nanoindentation Behavior of Molybdenum Surface-modified Titanium

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Journal of Wuhan University of Technology(Materials Science) 2013年第4期28卷 825-828页

作者：马永 YUAN Guozheng LI Zhigang zhang xiangyu 唐宾 Research Institute of Surface Engineering Taiyuan University of Technology Taiyuan 030024 China Research Institute of Applied Mechanics and Biomedical Engineering Taiyuan University of Technology

By using double glow plasma surface metallurgy technique, the molybdenum （Mo） surface- modified layer on titanium （Ti） was obtained. The corresponding cross-section morphology, phase formation, and element concentration were investigated by optical microscopy, X-ray diffraction （XRD）, and glow discharge optical emission spectroscopy （GDOES）, respectively. The experimental results indicate that the Mo modified layer is composed of a 1.7 μm pure Mo deposition layer and a 14.3μm Mo diffusion layer. Along the sample thickness direction, nanoindentation tests were performed on the cross-section of the Mo diffusion layer and the Ti substrate （for the comparison purpose） by Hysitron TI900 TriboIndenter. The 2D and 3D residual indentation profiles of the Mo diffusion layer were obtained by scanning probe microscopy （SPM）. The elastic modulus and hardness values of every indent were acquired and analyzed. According to the load-displacement curves, the plastic deformation degrees of the Mo diffusion layer and the Ti substrate were analyzed. It is indicated that the Mo diffusion layer possesses high strength-toughness.

关键词： Mo surface-modified Ti nanonindentation high strength-toughness

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