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Multifactor study of efficacy and recurrence in laparoscopic surgery for inguinal hernia

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World Journal of Clinical Cases 2021年第15期9卷 3559-3566页

作者： Wei-long Chen Qing-Qiang Deng Wei xu ming Luo Department of Pediatric Surgery Jiangxi Children's HospitalNanchang 330003Jiangxi ProvinceChina

BACKGROUND Inguinal hernia is a common clinical manifestation in children with a low selfhealing *** To determine the effect of laparoscopic surgery on indirect inguinal hernia and the risk factors for postoperative recurrence and to provide a reference for the clinical treatment and prevention of *** We selected 360 children who underwent laparoscopic high ligation in our hospital as the laparoscopic group and 120 patients treated for inguinal hernia with conventional surgery as the control *** operation time,blood loss,incision length,hospitalization time,total hospitalization cost and surgical complications were compared between the two *** to telephone follow-up or return visits,the children who had recurrence within 2 years after the operation in the laparoscopic group were analyzed,and the laparoscopic high ligation hernia sac level was analyzed by the logistic multifactor *** was used to treat recurrence in children with inguinal *** The operation time,blood loss,length of incision,and length of hospital stay in the laparoscopic group were lower than those in the control group(P3 years increased the risk of postoperative recurrence in children with inguinal hernia after laparoscopic high ligation of the hernia sac(P<0.05).CONCLUSION Laparoscopic surgery for in

关键词： Laparoscopic high ligation of the hernia sac Pediatric Inguinal hernia Recurrence Risk factors

J_2 invariant relative orbits via differential correction algorithm

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Acta Mechanica Sinica 2007年第5期23卷 585-595页

作者： ming xu Shijie xu School of Astronautics Beihang University Beijing 100083 China

This paper describes a practical method for finding the invariant orbits in Ja relative dynamics. Working with the Hamiltonian model of the relative motion including the J2 perturbation, the effective differential correction algorithm for finding periodic orbits in three-body problem is extended to formation flying of Earth＇s orbiters. Rather than using orbital elements, the analysis is done directly in physical space, which makes a direct connection with physical requirements. The asymptotic behavior of the invariant orbit is indicated by its stable and unstable manifolds. The period of the relative orbits is proved numerically to be slightly different from the ascending node period of the leader satellite, and a preliminary explanation for this phenomenon is presented. Then the compatibility between J2 invariant orbit and desired relative geometry is considered, and the design procedure for the initial values of the compatible configuration is proposed. The influences of measure errors on the invariant orbit are also investigated by the Monte-Carlo simulation.

关键词： Formation flying J2 invariant orbit Differential correction Formation configuration

The Minkowski norm and Hessian isometry induced by an isoparametric foliation on the unit sphere

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Science China Mathematics 2022年第7期65卷 1485-1516页

作者： ming xu School of Mathematical Sciences Capital Normal UniversityBeijing 100048China

Let M_(t) be an isoparametric foliation on the unit sphere(S^(n−1)(1),g^(st))with d principal *** the spherical coordinatesinduced by M_(t),we construct a Minkowski norm with the representation F=r√2f(t),which generalizes the notions of(α,β)-norm and(α1,α2)-*** the technique of the spherical local frame,we givean exact and explicit answer to the question when F=r√2 f(t)really defines a Minkowski *** the similar technique,we study the Hessian isometry Φ between two Minkowski norms induced by M_(t),which preservesthe orientation and fixes the spherical ξ-*** aretwo ways to describe this Φ,either by a system of ODEs,or by its restriction toany normal plane for M_(t),which is then reduced to a Hessian isometry between Minkowski norms on R^(2) satisfying certain symmetry and(d)-*** d>2,we prove that this Φ can be obtained by gluing positive scalar multiplications and compositions of the Legendre transformation and positive scalar multiplications,so it must satisfy the(d)-property for any orthogonal decomposition R^(n)=V'+V'',i.e.,for any nonzero x=x'+x'' and Φ(x)=x=x'+x''with x',x'∈V'and x'',x''∈V'',we have g_(x)^(F1)(x'',x)=g_(x)^(F2)x(x'',x).As byproducts,we prove the following *** the indicatrix(S_(F,g)),where F is a Minkowski norm induced by M_(t) and g is the Hessian metric,the foliation N_(t)=S_(F)∩R>_(0)M_(0) is *** Conjecture is valid for a Minkowski norm F induced by M_(t),i.e.,if its Hessian metric g is flat on R^(n)\{0}with n>2,then F is Euclidean.

关键词： Minkowski norm Hessian isometry Hessian metric isoparametric foliation Laugwitz Conjecture Legendre transformation

Relationship between dietary niacin intake and erectile dysfunction:a population-based study

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Asian Journal of Andrology 2024年第4期26卷 382-388页

作者： Wei-long Lin Cheng Zheng Hao-xu Wang Wei Zhang ming-En Lin Department of Urology The First Affiliated Hospital of Shantou University Medical CollegeMedical College of Shantou UniversityShantou 515041China The Second School of Clinical Medicine Southern Medical UniversityGuangzhou 510260China.

Existing research on the precise link between dietary niacin intake and erectile dysfunction(ED)is ***,this study aimed to investigate the potential association between dietary niacin intake and the risk of *** logistic regression and restricted cubic splines(RCSs)were used to examine the relationship between dietary niacin intake and *** interaction analysis was performed to assess the impact of different subgroups on the study *** addition,1:1 propensity score matching(PSM)was employed to adjust for potential confounding factors,ensuring the reliability of the *** analyzed data were collected from the 2001–2004 National Health and Nutrition Examination Survey(NHANES)in the *** study encompassed 3184 adults,among whom 863 participants were identified as having *** adjustments for potential confounders,the findings revealed that higher niacin intake,specifically in the highest tertile,was associated with a decreased risk of ED compared to that in the lowest tertile,showing an odds ratio(OR)of 0.56(95%confidence interval[CI]:0.37–0.85).Analysis of dose–response curves illustrated a negative correlation between dietary niacin intake and the risk of *** and interaction analyses fortified the consistency of these ***,PSM corroborated the validity of the *** study suggests an inverse association between dietary niacin intake and the risk of ***,establishing a cause-and-effect relationship remains elusive,and defining the safe threshold of niacin intake to prevent ED requires further investigation.

关键词： dietary niacin erectile dysfunction National Health and Nutrition Examination Survey propensity score matching

Homogeneous Finsler spaces with only one orbit of prime closed geodesics

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Science China Mathematics 2020年第11期63卷 2321-2342页

作者： ming xu School of Mathematical Sciences Capital Normal UniversityBeijing 100048China

When a closed Finsler manifold admits continuous isometric actions,estimating the number of orbits of prime closed geodesics seems a more reasonable substitution for estimating the number of prime closed *** extend the results of Duan,long,Rademacher,Wang and others on the existence of two prime closed geodesics to the equivariant situation,we propose the question if a closed Finsler manifold has only one orbit of prime closed geodesics if and only if it is a compact rank-one Riemannian symmetric *** this paper,we study this problem in homogeneous Finsler geometry,and get a positive answer when the dimension is even or the metric is *** guess the rank inequality and the algebraic techniques in this paper may continue to play an important role for discussing our question in the non-homogeneous situation.

关键词： homogeneous Finsler space closed geodesic compact rank-one symmetric space connected isometry group Killing vector field

Characterization of condensed phase nitric acid particles formed in the gas phase

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Journal of Environmental Sciences 2011年第3期23卷 412-418页

作者： long Jia Yongfu xu State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

The formation of nitric acid hydrates has been observed in a chamber during the dark reaction of NO2 with O3 in the presence of air. The size of condensed phase nitric acid was measured to be 40-100 nm and 20-65 nm at relative humidity （RH） ≤ 5% and RH = 67% under our experimental conditions, respectively. The nitric acid particles were collected on the glass fiber membrane and their chemical compositions were analyzed by infrared spectrum. The main components of nitric acid hydrates in particles are HNO3.3H2O and NO3-.xH2O （x≥ 4） at low RH, whereas at high RH HNO3.H2O, HNO3-2H2O, HNO3.3H2O and NO3--xH20 （x≥ 4） all exist in the condensed phase. At high RH ***2O （x ≤3） collected on the glass fiber membrane is greatly increased, while NO3-.xH2O （x ≥ 4） decreased, compared with low RH. To the best of our knowledge, this is the first time to report that condensed phase nitric acid can be generated in the gas phase at room temperature.

关键词： nitric acid particles relative humidity chamber

Physical Properties of Polymers under Soft and Hard Nanoconfinement: A Review

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Chinese Journal of Polymer Science 2020年第6期38卷 565-578页

作者： ming-Chao Ma Yun-long Guo University o f Michigan-Shanghai Jiao Tong University Joint Institute Shanghai Jiao Tong UniversityShanghai 200240China School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai200240China

Polymeric materials under nanoconfinements have substantially deviated physical properties with respect to the bulk,especially glass transition temperature,physical aging,and crystallization *** we highlight the leading methods for creating various confinement *** these systems,recent advances on hard and soft confinement effect for glass transition,physical aging,mechanical properties and crystallization of polymers are reviewed in ***,as nanoconfined systems in extreme conditions are experimentally inaccessible,simulation results describing confinement effect on such systems are also discussed.

关键词： Nanoconfinement Glass transition temperature Physical aging Mechanical properties Crystallization

Symmetry selective directionality in near-field acoustics

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National Science Review 2020年第6期7卷 1024-1035页

作者： Yang long Hao Ge Danmei Zhang Xiangyuan xu Jie Ren ming-Hui Lu ming Bao Hong Chen Yan-Feng Chen Center for Phononics and Thermal Energy Science China-EU Joint Center for Nanophononics Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology School of Physics Sciences and Engineering Tongji University Department of Materials Science and Engineering College of Engineering and Applied Sciences and National Laboratory of Solid State Microstructures Nanjing University Key Laboratory of Noise and Vibration Research Institute of Acoustics Chinese Academy of Sciences Collaborative Innovation Center of Advanced Microstructures Nanjing University Key Laboratory of Noise and Vibration Research Institute of Acoustics Chinese Academy of Sciences Beijing 100190 China and4Collaborative Innovation Center of Advanced Microstructures Nanjing University

Understanding unidirectional and topological wave phenomena requires the unveiling of intrinsic geometry and symmetry for wave dynamics. This is essential yet challenging for the flexible control of near-field evanescent waves, highly desirable in broad practical scenarios ranging from information communication to energy radiation. However, exploitations of near-field waves are limited by a lack of fundamental understanding about inherent near-field symmetry and directional coupling at sub-wavelengths, especially for longitudinal waves. Here, based on the acoustic wave platform, we show the efficient selective couplings enabled by near-field symmetry properties. Based on the inherent symmetry properties of three geometrically orthogonal vectors in near-field acoustics, we successfully realize acoustic Janus, Huygens,spin sources and quadrupole hybrid sources, respectively. Moreover, we experimentally demonstrate fertile symmetry selective directionality of those evanescent modes, supported by two opposite meta-surfaces. The symmetry properties of the near-field acoustic spin angular momenta are revealed by directly measuring local vectorial fields. Our findings advance the understanding of symmetries in near-field physics, supply feasible approaches for directional couplings, and pave the way for promising acoustic devices in the future.

关键词： acoustics near field symmetry

Effect of thermal aging on the fatigue crack growth behavior of cast duplex stainless steels

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International Journal of Minerals,Metallurgy and Materials 2015年第11期22卷 1163-1170页

作者： xu-ming Lü Shi-lei Li Hai-long Zhang Yan-li Wang Xi-tao Wang State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Collaborative Innovation Center of Steel Technology University of Science and Technology Beijing

The effect of thermal aging on the fatigue crack growth（FCG） behavior of Z3CN20？09M cast duplex stainless steel with low ferrite content was investigated in this study. The crack surfaces and crack growth paths were analyzed to clarify the FCG mechanisms. The microstructure and micromechanical properties before and after thermal aging were also studied. Spinodal decomposition in the aged ferrite phase led to an increase in the hardness and a decrease in the plastic deformation capacity, whereas the hardness and plastic deformation capacity of the austenite phase were almost unchanged after thermal aging. The aged material exhibited a better FCG resistance than the unaged material in the near-threshold regime because of the increased roughness-induced crack closure associated with the tortuous crack path and rougher fracture surface; however, the tendency was reversed in the Paris regime because of the cleavage fracture in the aged ferrite phases.

关键词： stainless steels fatigue crack growth thermal aging embrittlement fracture morphology