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Nuclear Science and Techniques 2024年第1期35卷 45-58页

作者： Yi-Xing Lu Wen-Cheng Fang Yu-Sen Guo Zhen-Tang Zhao shanghai institute of Applied Physics Chinese Academy of Sciences Shanghai 201800China University of Chinese Academy of Sciences Beijing 101408China shanghai Advanced Research institute Chinese Academy of Sciences Shanghai 201204China shanghai Key Laboratory of Cryogenics&Superconducting RF Technology Shanghai 201800China shanghaiTech University Shanghai 201210China

Radio frequency quadrupoles(RFQs),which are crucial components of proton injectors,significantly affect the performance of proton accelerator *** RFQ with a high frequency of 714 MHz dedicated to compact proton injectors for medi-cal applications is designed in this *** RFQ is designed to accelerate proton beams from 50 keV to 4 MeV within a short length of 2 m and can be matched closely with the downstream drift tube linac to capture more particles through a preliminary *** develop an advanced RFQ,challenging techniques,including fabrication and tuning method,must be evaluated and verified using a *** aluminium prototype is derived from the conceptual design of the RFQ and then redesigned to confirm the radio frequency performance,fabrication procedure,and feasibility of the tuning ***,a new tuning algorithm based on the response matrix and least-squares method is developed,which yields favorable results based on the prototype,i.e.,the errors of the dipole and quadrupole components reduced to a low level after several tuning *** from the conceptual design and techniques obtained from the prototype,the formal mechanical design of the 2-m RFQ is ready for the next manufacturing step.

关键词： Compact proton injector RFQ IH-DTL High gradient Tuning

Multi-blade rubbing characteristics of the shaft-disk-blade-casing system with large rotation

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Applied Mathematics and Mechanics(English Edition) 2024年第1期45卷 111-136页

作者： Zhiyuan WU Linchuan ZHAO Han YAN Ge YAN Ao CHEN Wenming ZHANG State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong UniversityShanghai 200240China shanghai institute of Aerospace Systems Engineering Shanghai 201108China

Blade rubbing faults cause detrimental impact on the operation of aeroengines. Most of the existing studies on blade rubbing in the shaft-disk-blade-casing(SDBC) system have overlooked the elastic deformation of the blade, while some only consider the whirl of the rotor, neglecting its spin. To address these limitations, this paper proposes a dynamic model with large rotation for the SDBC system. The model incorporates the spin and whirl of the rotor, enabling the realistic reproduction of multiblade rubbing faults. To verify the accuracy of the SDBC model with large rotation and demonstrate its capability to effectively consider the rotational effects such as the centrifugal stiffening and gyroscopic effects, the natural characteristics and dynamic responses of the proposed model are compared with those obtained from reported research and experimental results. Furthermore, the effects of the rotating speed, contact stiffness,and blade number on the dynamic characteristics of the SDBC system with multi-blade rubbing are investigated. The results indicate that the phase angle between the rotor deflection and the unbalance excitation force increases with the increasing rotating speed,which significantly influences the rubbing penetration of each blade. The natural frequency of the SDBC system with rubbing constrain can be observed in the acceleration response of the casing and the torsional response of the shaft, and the frequency is related to the contact stiffness. Moreover, the vibration amplitude increases significantly with the product of the blade number under rubbing, and the rotating frequency approaches the natural frequency of the SDBC system. The proposed model can provide valuable insight for the fault diagnosis of rubbing in bladed rotating machinery.

关键词： shaft-disk-blade-casing(SDBC) large rotation spin and whirl multi-blade rubbing rotational effect

Space truss construction modeling based on on-orbit assembly motion feature

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Chinese Journal of Aeronautics 2024年第3期37卷 365-379页

作者： Changjie ZHAO Weizhong GUO Meng CHEN Jiaxing HU Youcheng HAN Rongfu LIN State Key Lab of Mechanical System and Vibration Shanghai Jiao Tong UniversityShanghai 200240China institute of Aerospace System Engineering shanghai Shanghai 201109China

More space truss construction has been planned to develop and utilize space *** trusses are designed in the way of large-scale,complex,modular,and on-orbit *** meet the upcoming challenge of large-scale space infrastructure construction,it is necessary to study space truss automation design and robotic *** paper proposes an ordinal finite screw adjacency matrix model(OFSAMM),focusing on the relationship between assembly motions,to express and compute a space truss *** this model,a space truss is abstracted as a set of ordered assembly motions,each of which is recorded as a finite screw as the basic element of the truss and its *** operation of truss transformation is also derived under this ***,the truss configuration,the assembly sequence,the truss sub-assembly,the truss components,and the on-orbit assembly task can be expressed and calculated in a unified model,which is calculated and stores the truss topology and assembly with the minimum storage *** the end of this paper,we introduce how to synthesize and optimize space truss design through two *** study will help to improve design ***,it provides a theoretical basis for the automatic construction of space truss structures,especially in the next stage.

关键词： Adjacency matrix Finite screw On-orbit construction modeling Space applications Space trusses Topology design

Operational Characteristics of Loop Heat Pipe in Microgravity and Normal Gravity Environments

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Journal of Thermal Science 2024年第4期33卷 1394-1408页

作者： ZHONG Siyuan XIE Rongjian LI Yunfei SUN Xiaojin shanghai Institution of Technology and Physics Shanghai200083China University of Chinese Academy of Sciences Beijing100049China shanghai institute of Satellite Engineering Shanghai200240China

The loop heat pipe(LHP)is an advanced,efficient two-phase heat transfer unit,whose operational performance may be affected by microgravity conditions in contrast to ground-based *** performance of on-orbit temperature data and ground test of a copper-propylene LHP with a condenser temperature range of 243.15 K to 303.15 K were employed to compared and *** LHP has successfully started up for more than 193 times with a good heat transfer performance and a stable start-up stabilization on-orbit under a complex orbital heating environment for more than eight *** a small heat load(10.0W),the average start-up time is 110.0 s while the start-up temperature ranges from 5.71 K-12.78 *** start-up time at large temperature differences in the high temperature zone will be higher than the time required for start-up at smaller temperature differences in the low *** the condenser temperature is 250.0 K,the stable temperature difference on orbit is 3.83 K,which is generally consistent in heat transfer compared to 2.20 K in the ground *** this paper,we can conclude that the on-orbit flight data up to now can provide a reference to the design of subsequent LHP space applications.

关键词： Loop Heat Pipe(LHP) start up microgravity on-orbit experiment

An active high-static-low-dynamic-stiffness vibration isolator with adjustable buckling beams:theory and experiment

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Applied Mathematics and Mechanics(English Edition) 2024年第3期45卷 425-440页

作者： Kefan XU Muqing NIU Yewei ZHANG Liqun CHEN School of Science Harbin Institute of TechnologyShenzhen 518055Guangdong ProvinceChina College of Aerospace Engineering Shenyang Aerospace UniversityShenyang 110136China shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai Frontier Science Center of MechanoinformaticsShanghai Institute of Applied Mathematics and MechanicsSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai 200444China shanghai institute of Aircraft Mechanics and Control Shanghai 200092China

High-static-low-dynamic-stiffness(HSLDS)vibration isolators with buckling beams have been widely used to isolate external *** active adjustable device composed of proportion integration(PI)active controllers and piezoelectric actuators is proposed for improving the negative stiffness stroke of buckling beams.A nonlinear output frequency response function is used to analyze the effect of the vibration *** prototype of the active HSLDS device is built,and the verification experiment is *** results show that compared with the traditional HSLDS vibration isolator,the active HSLDS device can broaden the isolation frequency bandwidth,and effectively reduce the resonant amplitude by adjusting the active control *** maximum vibration reduction rate of the active HSLDS vibration isolator can attain 89.9%,and the resonant frequency can be reduced from 31.08 Hz to 13.28 ***,this paper devotes to providing a new design scheme for enhanced HSLDS vibration isolators.

关键词： active control high-static-low-dynamic-stiffness(HSLDS) vibration isola-tor dynamic analysis

Cone-beam computed tomography noise reduction method based on U-Net with convolutional block attention module in proton therapy

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Nuclear Science and Techniques 2024年第7期35卷 89-100页

作者： Xing-Yue Ruan Xiu-Fang Li Meng-Ya Guo Mei Chen Ming Lv Rui Li Zhi-Ling Chen shanghai institute of Applied Physics Chinese Academy of SciencesShanghai201800China University of Chinese Academy of Sciences Beijing100049China shanghai Advanced Research institute Chinese Academy of SciencesShanghai201210China Department of Radiation Oncology Ruijin HospitalShanghai Jiao Tong University School of MedicineShanghai200025China shanghai Key Laboratory of Proton therapy Shanghai201801China

Cone-beam computed tomography(CBCT) is mostly used for position verification during the treatment process. However,severe image artifacts in CBCT hinder its direct use in dose calculation and adaptive radiation therapy re-planning for proton therapy. In this study, an improved U-Net neural network named CBAM-U-Net was proposed for CBCT noise reduction in proton therapy, which is a CBCT denoised U-Net network with convolutional block attention modules. The datasets contained 20 groups of head and neck images. The CT images were registered to CBCT images as ground truth. The original CBCT denoised U-Net network, sCTU-Net, was trained for model performance comparison. The synthetic CT(SCT) images generated by CBAM-U-Net and the original sCTU-Net are called CBAM-SCT and U-Net-SCT images, respectively. The HU accuracies of the CT, CBCT, and SCT images were compared using four metrics: mean absolute error(MAE), root mean square error(RMSE), peak signal-to-noise ratio(PSNR), and structure similarity index measure(SSIM). The mean values of the MAE, RMSE, PSNR, and SSIM of CBAM-SCT images were 23.80 HU, 64.63 HU, 52.27 dB, and 0.9919, respectively,which were superior to those of the U-Net-SCT images. To evaluate dosimetric accuracy, the range accuracy was compared for a single-energy proton beam. The γ-index pass rates of a 4 cm × 4 cm scanned field and simple plan were calculated to compare the effects of the noise reduction capabilities of the original U-Net and CBAM-U-Net on the dose calculation results. CBAM-U-Net reduced noise more effectively than sCTU-Net, particularly in high-density tissues. We proposed a CBAM-U-Net model for CBCT noise reduction in proton therapy. Owing to the excellent noise reduction capabilities of CBAM-U-Net, the proposed model provided relatively explicit information regarding patient tissues. Moreover, it maybe be used in dose calculation and adaptive treatment planning in the future.

关键词： Proton therapy Cone-beam CT CBAM-U-Net γ-index

Al-doped ZnO/WO_(3) heterostructure films prepared by magnetron sputtering for isopropanol sensors

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Rare Metals 2024年第1期43卷 247-256页

作者： Wei-Xiang Gao Xue-Ting Chang Xiao-Jie Zhu Jun-Feng Li Ying-Chang Jiang Dong-Sheng Wang Chuan-Xiao Yang Shi-Bin Sun College of Logistics Engineering Shanghai Maritime UniversityShanghai 201306China College of Ocean Science and Engineering Shanghai Maritime UniversityShanghai 201306China institute of Logistics Science and Engineering Shanghai Maritime UniversityShanghai 201306China

Metal oxide semiconductors(MOSs) are ideal sensing materials for detecting volatile organic compounds due to their low cost, diversity, high stability, and ease of production. However, it remains a grand challenge to develop the MOSs-based gas sensors for sensing isopropanol with desired performance via a simple, effective,and controllable method. Herein, we reported the preparation of the Al-doped Zn O(AZO)/WO_(3) heterostructure films by directly depositing the AZO coating onto the WO_(3) coating using a strategy of magnetron sputtering. The AZO/WO_(3) heterostructure films were constructed by numbers of irregular nanoparticles that were interconnected with each other. The AZO/WO_(3) heterostructure films-based gas sensors exhibited excellent isopropanolsensing performance with high response, promising selectivity, low detection limit, fast response rate, wide detection range, and ideal reproducibility. The promising isopropanol-sensing performance of the AZO/WO_(3) heterostructure films arises mainly from their high uniformity, unique microstructures with high surface roughness,and the construction of the heterostructure between the AZO and WO_(3) coatings. This work provides a versatile approach to prepare the MOSs-based heterostructure films for assembling the gas sensors.

关键词： Metal oxide semiconductors Gas sensors Aldoped ZnO/WO_(3) Heterostructure films Isopropanol Magnetron sputtering

Multiparameter Numerical Investigation of Two Types of Moving Interactions Between the Deep-Sea Mining Vehicle Track Plate and Seabed Soil:Digging and Rotating Motions

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China Ocean Engineering 2024年第3期38卷 408-423页

作者： SUN Peng-fei LYU Hai-ning YANG Jian-min XU Zhi-yong State Key Laboratory of Ocean Engineering Shanghai Jiao Tong UniversityShanghai 200240China Yazhou Bay institute of Deepsea SCI-TECH Shanghai Jiao Tong UniversitySanya 572024China institute of Marine Equipment Shanghai Jiao Tong UniversityShanghai 200240China

To ensure the safe performance of deep-sea mining vehicles(DSMVs),it is necessary to study the mechanical characteristics of the interaction between the seabed soil and the track *** rotation and digging motions of the track plate are important links in the contact between the driving mechanism of the DSMV and seabed *** this study,a numerical simulation is conducted using the coupled Eulerian–Lagrangian(CEL)large deformation numerical method to investigate the interaction between the track plate of the DSMV and the seabed soil under two working conditions:rotating condition and digging ***,a soil numerical model is established based on the elastoplastic mechanical characterization using the basic physical and mechanical properties of the seabed soil obtained by in situ ***,the soil disturbance mechanism and the dynamic mechanical response of the track plate under rotating and digging conditions are obtained through the analysis of the sensitivity of the motion parameters,the grouser structure,the layered soil features and the soil *** results indicate that the above parameters remarkably influence the interaction between the DSMV and the seabed ***,it is important to consider the rotating and digging motion of the DSMV in practical engineering to develop a detailed optimization design of the track plate.

关键词： deep-sea mining vehicle rotating motion digging motion track plate-seabed soil interaction CEL numerical method

Conduction-convection coupled heat transfer around a hollow cylinder under different buoyancy forces

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Chinese Journal of Aeronautics 2024年第4期37卷 216-228页

作者： Wanyu ZHANG Jingyi WU Guang YANG institute of Refrigeration and Cryogenics Shanghai Jiao Tong UniversityShanghai 200240China

In order to clarify the effect of a buoyancy force on conduction–convection coupled heat transfer in a hollow cylinder, the flow and thermal characteristics were analyzed using an RNG k-ε turbulence model. The Reynolds number was fixed at 1.014 × 10^(6), and the Rayleigh number varied from 1.122 × 10^(10)to 1.088 × 10^(11). Results have shown that, when considering the effect of an opposed buoyancy force, increasing the Rayleigh number has a positive impact on the rate of change and uniformity of the cylinder temperature. The temperature distributions along the axial and circumferential directions are similar for different Rayleigh numbers, but extreme values *** the axial direction, the maximum temperature is obtained at the interface between the variable-diameter part and the constant-diameter part. The maximum dimensionless temperature value decreases to 0.12 when the Rayleigh number increases to 1.088 × 10^(11). Along the circumferential direction, the temperature distribution is affected by the buoyancy force, which results in the temperature of the upper part being higher than that of the lower part. After nondimensionalization of the temperature and time, a correlation was proposed to illustrate the transient heat transfer process quantitatively. The standard deviation of the maximum relative temperature, representing the temperature uniformity, was also calculated. It was found that the difference in the direction of the buoyancy force made a huge difference. Compared with the opposed buoyancy force, the maximum dimensionless temperature is almost two times higher with an assisted buoyancy force. Similarly, the heat transfer coefficient with an assisted buoyancy force is half of that with an opposed buoyancy force. Overall, an assisted buoyancy force plays a negative role in terms of thermal characteristics. The flow field around the hollow cylinder was also illustrated to reveal the mechanism of the buoyancy force on magnitude and direction aspects

关键词： Buoyancy Conduction-convection heat transfer Transient analysis Hollow cylinder Non-dimensionalization

Amplified internal electric field of Cs_(2)CuBr_(4)@WO_(3-x)S-scheme heterojunction for efficient CO_(2)photoreduction

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Journal of Energy Chemistry 2024年第5期92卷 521-533页

作者： Zhijie Zhang Xuesheng Wang Junyi Qian Jiayue Xu School of Materials Science and Engineering Shanghai Institute of TechnologyShanghai 201418China

Heterojunction construction,especially S-scheme heterojunction,represents an efficient universal strategy to achieve high-performance photocatalytic *** further performance stimulation of these well-designed heterojunctions,modulating the interfacial internal electric field(IEF)to steer dynamic charge transfer represents a promising ***,we realized the precise regulation of Fermi level(E_(F))of the oxidation semiconductor(mesoporous WO_(3-x))by tailoring the concentration of oxygen vacancies(V_(O)),maximizing the IEF intensity in Cs_(2)CuBr_(4)@WO_(3-x)(CCB@WO_(3-x))S-scheme *** augmented IEF affords a robust driving force for directional electron delivery,leading to boosted charge ***,the developed CCB@WO_(3-x)S-scheme heterojunction demonstrated outstanding photocatalytic CO_(2)reduction performance,with the electron consumption rate(Relectron)up to 390.34μmol g^(-1)h^(-1),which is 3.28 folds higher than that of pure *** in-depth analysis of the S-scheme electron transfer mode was presented via theoretical investigations,electron spin resonance(ESR),photo-irradiated Kelvin probe force microscopy(KPFM),and in-situ X-ray photoelectron spectroscopy(XPS).Finally,the CO_(2)photoconversion route was explored in detail using in-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)and DFT theoretical calculations.

关键词： Cs_(2)CuBr_(4) WO_(3-x) Oxygen vacancy S-scheme heterojunction Internal electricfield