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Three-Rigid-Body-Particle Modeling and Optimization of Trajectory and Posture for Alpine Skiing

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Journal of Systems Science & Complexity 2024年第2期37卷 581-608页

作者： zhang Yijia FEI qing YAO Xiaolan SUN Jian zhang Yanjun CHEN zhen School of Automation Beijing Institute of TechnologyBeijing 100081China

This paper presents a new study on modeling and optimization of trajectory and posture for the super-giant(SG)slalom of alpine *** is the first time that a Three-Rigid-Body-Particle model based on rigorous derivations and stability analysis is established to represent skiers trajectory and posture characteristics,as it is more accurate than the single-rigid-body model which is commonly used in existing *** addition,the Radau pseudospectral method is applied to solve the trajectory and posture optimization problem in order to obtain better skiing trajectory,skiing posture,and some key kinematic parameters of ***,this paper analyzes the effects of different body types,minimum turning radii,and flexor and extensor strength of knees and hip joint on skiing ***,based on the findings of the study,some advice about how to improve the performance of the SG slalom in view of science and technology is given to skiers and coaches for reference.

关键词： Alpine skiing modeling posture optimization Three-Rigid-Body-Particle model trajectory optimization

An Algebraic Method for Constructing Exact Solutions to Difference-Differential Equations

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Communications in Theoretical Physics 2006年第2期45卷 211-218页

作者： WANG zhen zhang Hong-qing Department of Applied Mathematics Dalian University of Technology Dalian 116024 China

在这篇论文，我们在场解决差别的一个方法微分方程。作为一个例子，我们把这个方法用于分离 KdV 方程和 Ablowitz-Ladik 格子方程。作为结果，许多准确答案包括夸张功能 sinh 和大头棍介绍的 solitonsolutions 在枫树的帮助下被获得，... 详细信息

在这篇论文，我们在场解决差别的一个方法微分方程。作为一个例子，我们把这个方法用于分离 KdV 方程和 Ablowitz-Ladik 格子方程。作为结果，许多准确答案包括夸张功能 sinh 和大头棍介绍的 solitonsolutions 在枫树的帮助下被获得，周期的答案由罪恶 andcos 和合理答案介绍了。这个方法能也习惯于另外的非线性的 difference-differentialequation (s) 。

关键词：代数法精确解法差分-微分方程离散KdV方程 Ablowitz-Ladik晶格方程

Configuring single-layer MXene nanosheet onto natural wood fiber via C-Ti-C covalent bonds for high-stability Li-S batteries

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Journal of Energy Chemistry 2024年第8期95卷 701-711,I0016页

作者： Yangyang Chen Yu Liao Ying Wu Lei Li zhen zhang Sha Luo Yiqiang Wu Yan qing College of Materials Science and Technology Central South University of Forestry and TechnologyChangsha 410004HunanChina

Lithium-sulfur batteries(LSBs)are considered promising candidates for next-generation battery technologies owing to their outstanding theoretical energy density and ***,the low conductivity and polysulfide shuttling effect of S cathodes severely hamper the practical performance of ***,in situ-generated single layer MXene nanosheet/hierarchical porous carbonized wood fiber(MX/PCWF)composites are prepared via a nonhazardous eutectic activation strategy coupled with pyrolysis-induced gas *** unique architecture,wherein single layer MXene nanosheets are constructed on carbonized wood fiber walls,ensures rapid polysulfide conversion and continuous electron transfer for redox *** C-Ti-C bonds formed between MXene and PCWF can considerably expedite the conversion of polysulfides,effectively suppressing the shuttle *** impressive capacity of 1301.1 m A h g^(-1)at 0.5 C accompanied by remarkable stability is attained with the MX/PCWF host,as evidenced by the capacity maintenance of 722.6 m A h g^(-1)after 500 ***,the MX/PCWF/S cathode can still deliver a high capacity of 886.8 m A h g^(-1)at a high S loading of 5.6 mg cm^(-2).The construction of two-dimensional MXenes on natural wood fiber walls offers a competitive edge over S-based cathode materials and demonstrates a novel strategy for developing high-performance batteries.

关键词： Lithium-sulfur batteries S cathodes MXene nanosheets Wood fiber C-Ti-C bonds

Reducing Operation Emissions and Improving Work Efficiency Using a Pure Electric Wheel Drive Tractor

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Engineering 2024年第6期37卷 230-245页

作者： Chang-Kai Wen Wen Ren qing-zhen Zhu Chun-Jiang Zhao zhen-Hao Luo Sheng-Li zhang Bin Xie Zhi-Jun Meng Research Center of Intelligent Equipment Beijing Academy of Agriculture and Forestry SciencesBeijing 100097China State Key Laboratory of Intelligent Agricultural Power Equipment Beijing 100097China BYD Company Limited Shenzhen 518118China College of Agricultural Engineering Jiangsu UniversityZhenjiang 212013China College of Engineering China Agricultural UniversityBeijing 100083China

In response to the problems of excessive greenhouse-gas and particulate emissions and the low traction efficiency of conventional diesel tractors in the field,a purely electric wheel-side drive tractor was studied,including an electric motor drive system,a battery ballast system,and an electro–hydraulic suspension *** paper develops a dynamics model of an electric tractor-ploughing unit under complex soil conditions,leading to the proposal of an active control method for drive wheel torque and a joint control method for the traction force of the suspension system and the front-and rear-axle loads of a ***,the tractor is prototyped and assembled,and ploughing tests are carried *** ploughing results show that the active torque-distribution control method proposed in this study reduces the tractor slip by 14.83%and increases the traction efficiency by 10.28%compared with the average torquedistribution *** with the conventional traction control mode,the joint control method for traction and ballast proposed in this paper results in a 3.7%increase in traction efficiency,a 15.05%decrease in slip,and a 4.9%reduction in total drive motor energy *** study will help to improve the operation quality and traction efficiency of electric tractors in complex soil conditions.

关键词： Electric tractor Ploughing unit Torque distribution Active ballast Traction performance

Astrometric Observations of NEA 1998 HH49 Using the Daocheng 50 cm Telescope

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Research in Astronomy and Astrophysics 2024年第7期24卷 74-81页

作者： Huan Xu Xiang-Ming Cheng Yi-Gong zhang Teng-Fei Song zhen-Jun zhang qing-Yu Peng Yunnan Observatories Chinese Academy of Sciences University of Chinese Academy of Sciences Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Engineering Laboratory on Applied Astronomical Technology of Yunnan School of Information Engineering Kunming University School of Computer Science and Information Engineering Anyang Institute of Technology Department of Computer Science Jinan University Sino-French Joint Laboratory for Astrometry Dynamics and Space ScienceJinan University

This study details an astrometric observation campaign of the Near-Earth Asteroid 1998 HH49, conducted with the aim of refining our understanding of its physical characteristics. Utilizing the 50 cm telescope located at the Wumingshan Mountain in Daocheng, Sichuan, images were obtained over four nights, from 2023 October 19 to October 22. These observations were processed using Astrometrica software, facilitating the precise determination of the asteroid's position. The observational results were compared with the ephemerides from three distinct sources to verify accuracy: the Jet Propulsion Laboratory(JPL) Horizons System, the Institut de Mécanique Céleste et de Calcul des éphémérides(IMCCE) Miriade, and the Near-Earth Objects Dynamic Site(NEODyS-2).When compared with the JPL ephemeris, a mean observed-minus-calculated(O-C) result of 0.''07 in the *** and-0.''35 in the decl. direction was yielded. Furthermore, the comparison with the IMCCE ephemeris yielded mean O-C results of 0.''08 in the R.A. direction and-0.''06 in the decl. direction. The comparison with the NEODyS-2 ephemeris yielded the mean O-C results of 0.''06 in R.A. and-0.''49 in decl. direction. The study's findings demonstrate a general consistency between the observed data and the ephemeris predictions, with minor discrepancies observed across the data sets. Notably, both the JPL and NEODyS-2 ephemerides show that the residuals in the decl. direction exceed those in the R.A. direction. The disparities may result from atmospheric differential color refraction, ephemeris discrepancies, observational errors, and other factors. Additionally, it is worth noting that further investigation is required due to the potential influence of additional factors. Overall, the Daocheng 50 cm Telescope exhibits the ability to conduct high-precision positional measurements.

关键词： astrometry ephemerides time

Nuclear charge radius predictions by kernel ridge regression with odd-even effects

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Nuclear Science and Techniques 2024年第2期35卷 94-102页

作者： Lu Tang zhen-Hua zhang Mathematics and Physics Department North China Electric Power UniversityBeijing 102206China Hebei Key Laboratory of Physics and Energy Technology North China Electric Power UniversityBaoding 071000China

The extended kernel ridge regression(EKRR)method with odd-even effects was adopted to improve the description of the nuclear charge radius using five commonly used nuclear *** are:(i)the isospin-dependent A^(1∕3) formula,(ii)relativistic continuum Hartree-Bogoliubov(RCHB)theory,(iii)Hartree-Fock-Bogoliubov(HFB)model HFB25,(iv)the Weizsacker-Skyrme(WS)model WS*,and(v)HFB25**** the last two models,the charge radii were calculated using a five-parameter formula with the nuclear shell corrections and deformations obtained from the WS and HFB25 models,*** each model,the resultant root-mean-square deviation for the 1014 nuclei with proton number Z≥8 can be significantly reduced to 0.009-0.013 fm after considering the modification with the EKRR *** best among them was the RCHB model,with a root-mean-square deviation of 0.0092 *** extrapolation abilities of the KRR and EKRR methods for the neutron-rich region were examined,and it was found that after considering the odd-even effects,the extrapolation power was improved compared with that of the original KRR *** strong odd-even staggering of nuclear charge radii of Ca and Cu isotopes and the abrupt kinks across the neutron N=126 and 82 shell closures were also calculated and could be reproduced quite well by calculations using the EKRR method.

关键词： Nuclear charge radius Machine learning Kernel ridge regression method

Design Research of a Novel Aftercool-Humidifier Concept for Humid Air Turbine Cycle

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Journal of Thermal Science 2024年第3期33卷 951-969页

作者： zhang Junzheng XU zhen School of Energy and Power Engineering Shandong UniversityJi’nan250061China Shandong Engineering Laboratory for High-efficiency Energy Conservation and Energy Storage Technology&Equipment Shandong UniversityJi’nan250061China

Humid air turbine cycle(HAT)has potential of electrical efficiencies comparable to combined cycle,with lower investment cost and NO_(x) *** typical heat exchanger network of HAT consists of intercooler(if there is),aftercooler,recuperator,economizer and humidifier,which brings higher efficiency but makes the system more *** simplify HAT layout,a novel humidifier concept is proposed by integrating the aftercooler into traditional counter-current *** on this concept,a one-dimensional model including pressure drop and exergy calculation is established to distinguish the thermodynamic and hydrodynamic characteristics,and then the structural parameters,such as the number of rows and columns,tube diameter,pitch and type for a micro HAT are *** results show that the aftercool-humidifier plays the same role as original aftercooler and humidifier,and can match the in-tube air,out-tube air and water stream well with lower *** the case of micro HAT cycle,the volume of heat and mass transfer area can be reduced by 47%compared with traditional *** major thermal resistance occurred in the convection heat transfer process inside the tube;however,using enhanced tube cannot effectively improve the compactness of device.

关键词： humid air turbine cycle humidifier thermodynamic analysis one-dimensional model

Will partial splenic embolization followed by splenectomy increase intraoperative bleeding?

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World Journal of Gastrointestinal Surgery 2024年第2期16卷 318-330页

作者： Long Huang qing-Lin Li qing-Sheng Yu Hui Peng Zhou zhen Yi Shen Qi zhang Department of No.1 Surgery The First Hospital Affiliated to Anhui University of Traditional Chinese MedicineHefei 230031Anhui ProvinceChina Anhui University of Traditional Chinese Medicine Anhui University of Traditional Chinese MedicineHefei 230038Anhui ProvinceChina Department of Surgery The Second Hospital Affiliated to Anhui University of Traditional Chinese MedicineHefei 230061Anhui ProvinceChina

BACKGROUND Partial splenic embolization(PSE)has been suggested as an alternative to splenectomy in the treatment of ***,some patients may experience recurrence of hypersplenism after PSE and require ***,there is a lack of evidence-based medical support regarding whether preoperative PSE followed by splenectomy can reduce the incidence of *** To investigate the safety and therapeutic efficacy of preoperative PSE followed by splenectomy in patients with cirrhosis and *** Between January 2010 and December 2021,321 consecutive patients with cirrhosis and hypersplenism underwent splenectomy at our *** on whether PSE was performed prior to splenectomy,the patients were divided into two groups:PSE group(n=40)and non-PSE group(n=281).Patient characteristics,postoperative complications,and follow-up data were compared between *** score matching(PSM)was conducted,and univariable and multivariable analyses were used to establish a nomogram predictive model for intraoperative bleeding(IB).The receiver operating characteristic curve,Hosmer-Lemeshow goodness-of-fit test,and decision curve analysis(DCA)were employed to evaluate the differentiation,calibration,and clinical performance of the *** After PSM,the non-PSE group showed significant reductions in hospital stay,intraoperative blood loss,and operation time(all P=0.00).Multivariate analysis revealed that spleen length,portal vein diameter,splenic vein diameter,and history of PSE were independent predictive factors for IB.A nomogram predictive model of IB was constructed,and DCA demonstrated the clinical utility of this *** groups exhibited similar results in terms of overall survival during the follow-up *** Preoperative PSE followed by splenectomy may increase the incidence of IB and a nomogram-based prediction model can predict the occurrence of IB.

关键词： Partial splenic embolization Splenectomy Hypertension,Portal Liver Cirrhosis Intraoperative bleeding

Heterochronous multiple primary prostate cancer and lymphoma:A case report

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World Journal of Clinical Cases 2024年第7期12卷 1333-1338页

作者： Jin-Long Liang Yu-qing Bu Li-Li Peng Hong-zhen zhang Department of Oncology Hebei General HospitalShijiazhuang 050051Hebei ProvinceChina

BACKGROUND Multiple primary malignant tumors(MPMTs)are rare type of cancer,especially when solid tumors are the first and lymphoma is the second primary *** report a patient with heterochronous MPMTs consisting of prostate cancer and rectal diffuse large B-cell lymphoma(DLBCL).CASE SUMMARY We report a 77-year-old male patient diagnosed with prostate cancer who was treated with radiation therapy and one year of endocrine therapy with bicalutamide(50 mg per day)and an extended-release implant of goserelin(1/28 d).Seven years later,rectal DLBCL with lung metastases was *** Although rare,the possibility of prostate cancer combined with a double primary cancer of DLBCL can provide a deeper understanding.

关键词： Multiple primary malignant tumors Radiation therapy Diffuse large B-cell lymphoma Prostate cancer Non-Hodgkin lymphoma Case report