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Isotropic volumetric MRI for displaying cranial perineural spread of cranial nerve in nasopharyngeal carcinoma

中国医学影像技术 2024年第8期40卷 1164-1169页

作者： ZHENG Dechun XU Shugui LAI Guojing HU Chunmiao CAO Xisheng feng meimei PENG Li Department of Radiology Clinical Oncology School of Fujian Medical UniversityFujian Cancer HospitalFuzhou 350014China Department of Radiation Oncology Clinical Oncology School of Fujian Medical UniversityFujian Cancer HospitalFuzhou 350014China

Objective To observe the value of isotropic volumetric MRI for displaying perineural spread(PNS)of cranial nerve(CN)in nasopharyngeal *** Eighty-seven patients with pathologically proven nasopharyngeal carcinoma were prospectively *** scanning,including three-dimensional liver acquisition with volume acceleration-flexible(3D LAVA_Flex)image,T2WI with fat suppression(T2WI-FS),T1WI,contrast enhancement(CE)T1WI-FS of nasopharynx and neck region were *** displaying rates of CN PNS were evaluated and compared between 3D LAVA_Flex and T2WI-FS,T1WI,CE-T1WI-FS at patient level,CN group level and neural level,*** The displaying rate of CN PNS in all 87 nasopharyngeal carcinoma patients by 3D LAVA_Flex sequence was 49.43%(43/87),higher than that of conventional MRI(30/87,34.48%,P=0.001).Among 59 patients with advanced nasopharyngeal carcinoma diagnosed with conventional sequences,the displaying rate of CN PNS was 71.19%(42/59)by 3D LAVA-Flex sequence,higher than that of conventional MRI(30/59,50.85%,P=0.001).At both patient level and posterior CN level,significant differences of the displaying rate of CN PNS were found between 3D LAVA-Flex sequence and T2WI-FS,T1WI,CE-T1WI-FS,while at CN level,the displaying rates of mandibular nerve PNS,CNⅨ—ⅪPNS in jugular foramen(P<0.05)and CNⅨ—ⅫPNS in carotid space of 3D LAVA_Flex sequence were all significantly higher than that of T2WI-FS,T1WI and CE-T1WI-FS(all P<0.05),of PNS of CNⅢ—Ⅴin cavernous sinus were higher than that of T2WI-FS(P<0.05),while of PNS of hypoglossal nerve were significantly higher than that of T2WI-FS and T1WI(both P<0.05).Conclusion 3D LAVA_Flex sequence could be used to effectively display CN PNS of nasopharyngeal carcinoma.

关键词： nasopharyngeal neoplasm cranial nerve magnetic resonance imaging neoplasm metastasis prospective studies

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孔隙水实时作用下冻结饱水砂岩的三轴压缩试验

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采矿与安全工程学报 2024年第4期41卷 836-844页

作者：冯梅梅袁抗生中国矿业大学深地工程智能建造与健康运维全国重点实验室力学与土木工程学院江苏徐州221116

为研究孔隙水压力实时作用下冻结饱水砂岩的力学特性,开展了4个地应力梯度下砂岩常温(20℃)和负温(-5℃)、有孔隙水压力和无孔隙水压力条件下的三轴压缩力学特性研究,并对冻结前后砂岩试样进行微观扫描电镜测试。结果表明:低温冻结可以... 详细信息

为研究孔隙水压力实时作用下冻结饱水砂岩的力学特性,开展了4个地应力梯度下砂岩常温(20℃)和负温(-5℃)、有孔隙水压力和无孔隙水压力条件下的三轴压缩力学特性研究,并对冻结前后砂岩试样进行微观扫描电镜测试。结果表明:低温冻结可以强化砂岩试样的三轴抗压强度,冻结后形成的孔隙冰可以隔绝孔隙水的流动;孔隙水压力在常温和负温情况下均会弱化砂岩三轴抗压强度,且在常温状态下更为显著;随着地应力的增大,常温情况下孔隙水压力对砂岩试样三轴抗压强度的弱化作用逐渐变强,负温情况下则相反;有孔隙水压力冻结的砂岩弹性模量普遍低于同地应力条件下无孔隙水压力冻结砂岩试样,且弹性模量随着地应力的增大先增长然后逐渐衰弱;砂岩试样在常温条件下加载破坏面多为平滑的剪切破坏,冻结之后破坏面多呈“S”状;有孔隙水压作用的砂岩试样微观结构中有更多的冻结散落颗粒和碎屑,冻结条件下更为显著。

关键词：冻结砂岩孔隙水压力三轴压缩强度演化规律微观结构

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Experimental investigation on dilatancy behavior of water-saturated sandstone

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International Journal of Mining Science and Technology 2018年第2期28卷 323-329页

作者： Jiangyu Wu meimei feng Bangyong Yu Wenli Zhang Xiaoyan Ni Guansheng Han State Key Laboratory for Geomechanics & Deep Underground Engineering China University of Mining & Technology School of Mechanics & Civil Engineering China University of Mining & Technology Institute of Construction Engineering Technology Changzhou Vocational Institute of Engineering

It is important to study the dilatancy property of water-saturated rock for understanding the engineering behavior of loaded rock mass. This study carried out the uniaxial and triaxial compressive experiments on the water-saturated red sandstone, analyzed the influences of confining pressure and pore pressure on dilatancy property of water-saturated rock, and discussed the reasonable basis of the stress of dilatancy onset as a strength design parameter of rock engineering, finally established the prediction model of the stress of dilatancy onset under the impacts of confining pressure and pore pressure. The results show that the strength parameters(the stress of dilatancy onset and peak strength) and deformation parameters(axial strain and circumferential strain) of water-saturated sandstone increase with the confining pressure, and the relations can be fitted with a positive linear function. The cohesion and internal friction angle obtained from the stress of dilatancy onset decrease by 11.57% and 7.33%, respectively, when compared with those obtained from the peak strength. The strength parameters and deformation parameters of water-saturated sandstone decrease basically with the increase of pore pressure, in which the relations between strength parameters or axial strain and pore pressure can be fitted with a negative linear function. However, the relation between the peak circumferential strain and the pore pressure should be characterized by a negative exponential function, and the circumferential strain at dilatancy onset isn't affected by the pore pressure.

关键词： Rock mechanics Dilatancy behavior Confining pressure Pore pressure Water-saturated

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Roadway deformation during riding mining in soft rock

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International Journal of Mining Science and Technology 2012年第4期22卷 539-544页

作者： Zhao Guozhen Ma Zhanguo Zhu Qinghua Mao Xianbiao feng meimei State Key Laboratory of Geomechanics and Deep Underground Engineering China University of Mining&TechnologyXuzhou 221008China School of Mechanics and Civil Engineering China University of Mining&Technology Xuzhou 221008China Zhangshuanglou Mine of Xuzhou Mine Group Xuzhou 221616China

"Riding mining" is a form of mining where the working face is located above the roadway and advances parallel to *** mining in deep soft rock creates a particular set of problems in the roadway that include high stresses,large deformations,and support *** we describe a study of the rock deformation mechanism of a roadway as observed during riding mining in deep soft *** analysis,numerical simulations,and on site monitoring were used to examine this *** stress in the rock and the visco-elastic behavior of the rock are *** time data,recorded over a period of 240 days,were taken from a 750 transportation *** distributions in the rock surrounding the roadway were studied by comparing simulations to observations from the *** rock stress shows dynamic behavior as the working face *** pressure increases and then drops after peaking as the face *** elastic and plastic deformation of the surrounding rock *** deformation provides a mechanism by which stress in the rock relaxes due to material flow.A way to rehabilitate the roadway is suggested that will help ensure mine safety.

关键词：巷道变形深部软岩开采行驶岩石应力采矿工作面煤矿安全生产变形机制

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A novel method for AFRPs burrs removal:Principle of mechanochemo-induced fiber fracture

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Chinese Journal of Aeronautics 2024年第7期37卷 522-538页

作者： Jie XU Bo LI Pingfa feng Qiang WANG feng feng Division of Advanced Manufacturing Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055China Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China Changhe Aircraft Industry(Group)Co.Ltd Jingdezhen 333000China

Burrs generated during the machining of Aramid-Fiber-Reinforced Composites(AFRPs)pose a challenge for the production efficiency of aircraft and helicopter housing *** studies have generally attempted to suppress burrs by referring to delamination suppression *** contrast to stratification,burrs are remediable machining *** such,a mechanochemical method with burrs trimming technological strategy are implemented to effectively combat ***,we clarify the mechanism by which aramid fibers cannot be cut off using analytical and numerical *** addition,the mechanism of fiber fracture with Modified Polyurethane Reactive Polymer(M-PUR),and development of anti-burr devices(thermostatic adhesive sealed generator)are ***,the experimental results show that the reduction rate in burr length is 87%-91%through the mechanochemical *** method not only opens a new avenue to solve the burr problem of aramid fibers but also builds an interdisciplinary bridge between polymer science and composite machining.

关键词： Mechanochemical method Burrs Orthogonal cutting Aramid fiber-reinforced composites Milling

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Derivation of Expanded Isospectral-Nonisospectral Integrable Hierarchies via the Column-vector Loop Algebra

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Acta Mathematicae Applicatae Sinica 2024年第3期40卷 778-800页

作者： Hai-feng WANG Yu-feng ZHANG School of Science Jimei UniversityXiamen 361021China School of Mathematics China University of Mining and TechnologyXuzhou 221116China

A scheme for generating nonisospectral integrable hierarchies is *** on the method,we deduce a nonisospectral hierarchy of soliton equations by considering a linear spectral *** follows that the corresponding expanded isospectral and nonisospectral integrable hierarchies are deduced based on a 6 dimensional complex linear space ■.By reducing these integrable hierarchies,we obtain the expanded isospectral and nonisospectral derivative nonlinear Schr?dinger *** using the trace identity,the biHamiltonian structure of these two hierarchies are also ***,some symmetries and conserved quantities of the resulting hierarchy are discussed.

关键词： expanded isospectral-nonisospectral integrable hierarchies column-vector loop algebra bi-Hamiltonian structure symmetry

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Carbon-based materials with combined functions of thermal management and electromagnetic protection: Preparation, mechanisms, properties, and applications

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Nano Research 2024年第3期17卷 883-903页

作者： Junwei Yue Yiyu feng Mengmeng Qin Wei feng School of Materials Science and Engineering and Tianjin Key Laboratory of Composite and Functional Materials Tianjin UniversityTianjin 300350China

The proliferation of high-power,highly informationized,and highly integrated electronic devices and weapons equipment has given rise to increasingly conspicuous issues about electromagnetic(EM)pollution and thermal *** issues,in turn,impose constraints on the performance of such equipment and jeopardize personnel *** materials,owing to their diverse and modifiable structures,offer adjustable thermal and electric conductivity,rendering them highly promising for applications in fields such as thermal management and EM protection which have garnered extensive research and *** pursuit of integrated device and equipment development has elevated the demand for multifunctional materials,prompting significant research into carbon-based composite materials that include both thermal management and EM protection ***,there are no relevant reviews on this topic at ***,this work consolidates research findings from recent years on carbon matrix composites exhibiting dual attributes of thermal management and EM *** attributes include thermally conductive electromagnetic interference(EMI)shielding materials,thermally insulating EMI shielding materials,thermally conductive EM wave(EMW)absorbing materials,and thermally insulating EMW absorbing *** paper elucidates the fundamental principles underpinning thermal conduction,thermal insulation,EMW absorbing,and EMI ***,it engages in discussions surrounding areas of contention,design strategies,and the functional properties of various material ***,the paper concludes by presenting the challenges encountered and potential research strategies about composites endowed with both thermal management and EM protection functionalities,while also envisaging the development of novel multifunctional EM protection materials.

关键词： carbon-based composites electromagnetic interference shielding microwave absorption thermal conduction thermal insulation

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Design and identification of a double-acting piezoelectric-hydraulic hybrid actuator

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Chinese Journal of Aeronautics 2024年第3期37卷 456-467页

作者： Junjian ZHANG Zhihua feng Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes University of Science and Technology of ChinaHefei 230026China

Traditional single-acting piezoelectric-hydraulic hybrid actuators usually have the problem of inertial force caused by flow pulsation of the liquid,which degrades their output *** suppress or solve the associated inertial force and enhance its output capabilities,this paper proposes a new type of double-acting piezoelectric-hydraulic hybrid actuator with four check valves acting as mechanical *** new hybrid actuator was fabricated and its output performance was *** the voltage is 700 Vp-pand the bias pressure is 2 MPa,the pulsation ratesδof the new actuator at 400 Hz,500 Hz and 600 Hz are 2.29,2.08 and 1.78,respectively,whileδof the single-acting hybrid actuator under the same conditions are 10.98,11.05 and ***,the liquid pulsation rate of the new hybrid actuator is significantly reduced,which is beneficial for improving the flow uniformity and weakening the influence of inertial force on the hybrid *** strategy ultimately leads to a maximum no-load velocity of 168.1 mm/s at 600 Hz and a maximum blocking force of 141 N at 450 Hz for the new hybrid *** addition,this strategy has the potential to be used in other electrohydrostatic actuators to improve their performance.

关键词： Double-acting Flow pulsation Inertial force Piezoelectric actuators Piezoelectric devices Piezoelectric hydraulic actuation Piezoelectric pump

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Rational Solutions of First Order Algebraic Ordinary Differential Equations

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Journal of Systems Science & Complexity 2024年第2期37卷 567-580页

作者： feng Shuang SHEN Liyong School of Physical and Mathematical Sciences Nanjing Tech UniversityNanjing 211816China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China

Let f(t,y,y')=∑ _(i=0)^(n )a_(i)(t,y)y'^(i)=0 be an irreducible first order ordinary differential equation with polynomial *** in 1998 proved that there exists a constant C such that every rational solution of f(t,y,y')=0 is of degree not greater than *** show that this degree bound C depends not only on the degrees of f in t,y,y' but also on the coefficients of f viewed as the polynomial in t,y,y'.In this paper,the authors show that if f satisfies deg(f,y)0,then the degree bound C only depends on the degrees of f in t,y,y',and furthermore we present an explicit expression for C in terms of the degrees of f in t,y,y'.

关键词： Degree bound first order AODE height rational solution

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Turbulence Statistics of Thermo-Buoyancy Supercritical Fuel Flow in a Regenerative Cooling Channel

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Journal of Thermal Science 2024年第1期33卷 126-137页

作者： SUN feng XIE Gongnan School of Marine Science and Technology Northwestern Polytechnical UniversityXi'an 710072China Department of Thermal Engineering Tsinghua UniversityBeijing 100084China

Active regenerative cooling with supercritical hydrocarbon fuel is considered as the most promising thermal protection *** existence of buoyancy force would lead to strongly anisotropic flow and thermal transport *** is closely related to the cooling performance of the *** elucidate the mechanisms of turbulent transport,the large eddy simulation(LES) was performed to assess turbulence statistics within different turbulence *** results indicated that the buoyancy and inertial force together dominated the change of turbulent ***,the spatial thermal buoyancy effect significantly suppressed the vertical velocity *** is due to the laminar motion caused by the buoyancy force,thereby weakening the thermal *** the statistics of velocity fluctuation,it was found that the buoyancy force and inertial force greatly weaken the vertical and streamwise velocity fluctuation,*** the statistics of thermal transport,the results pointed out that the near-wall heat transport characteristics need to be paid more *** thickness of the temperature mixing boundary layer led to the attenuation of vertical heat flux,which inhibited vertical temperature diffusion and predisposed to extreme conditions of heat transfer *** results can enhance the academic understanding of the heat transfer mechanism of supercritical fluids,and give guidance for further applications of thermal protection.

关键词： active regenerative cooling large eddy simulation(LES) buoyancy force turbulence statistics

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