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Simplified prediction models for acoustic installation effects of train-mounted equipment

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railway Engineering Science 2024年第2期32卷 125-143页

作者： David thompson Dong Zhao Giacomo Squicciarini Institute of Sound and Vibration research University of SouthamptonSouthampton SO171BJUK

Acoustic models of railway vehicles in standstill and pass-by conditions can be used as part of a virtual certification process for new *** each piece of auxiliary equipment,the sound power measured on a test bench is combined with meas-ured or predicted transfer *** is important,however,to allow for installation effects due to shielding by fairings or the train *** the current work,fast-running analytical models are developed to determine these installation *** model for roof-mounted sources takes account of diffraction at the corner of the train body or fairing,using a barrier *** equipment mounted under the train,the acoustic propagation from the sides of the source is based on free-field Green’s *** bottom surfaces are assumed to radiate initially into a cavity under the train,which is modelled with a simple diffuse field *** sound emitted from the gaps at the side of the cavity is then assumed to propagate to the receivers according to free-field Green’s *** show good agreement with a 2.5D boundary element model and with *** uncertainty and parametric uncertainty are *** largest variability occurs due to the height and impedance of the ground,especially for a low *** leads to standard deviations of up to 4 dB at low *** the roof-mounted sources,uncertainty over the location of the corner used in the equivalent barrier model can also lead to large standard deviations.

关键词： Train noise Auxiliary equipment Acoustic installation effects Virtual certification Uncertainty

Polyethylene glycol fusion repair of severed rat sciatic nerves reestablishes axonal continuity and reorganizes sensory terminal fields in the spinal cord

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Neural regeneration research 2025年第7期20卷 2095-2107页

作者： Emily A.Hibbard Liwen Zhou Cathy Z.Yang Karthik Venkudusamy Yessenia Montoya Alexa Olivarez George D.Bittner dale r.Sengelaub Program in Neuroscience Indiana UniversityBloomingtonINUSA Department of Neuroscience University of Texas at AustinAustinTXUSA

Peripheral nerve injuries result in the rapid degeneration of distal nerve segments and immediate loss of motor and sensory functions;behavioral recovery is typically *** used a plasmalemmal fusogen,polyethylene glycol(PEG),to immediately fuse closely apposed open ends of severed proximal and distal axons in rat sciatic *** have previously reported that sciatic nerve axons repaired by PEG-fusion do not undergo Wallerian degeneration,and PEG-fused animals exhibit rapid(within 2–6 weeks)and extensive locomotor ***,our previous report showed that PEG-fusion of severed sciatic motor axons was non-specific,i.e.,spinal motoneurons in PEG-fused animals were found to project to appropriate as well as inappropriate target *** this study,we examined the consequences of PEG-fusion for sensory axons of the sciatic *** adult male and female rats(Sprague–Dawley)received either a unilateral single cut or ablation injury to the sciatic nerve and subsequent repair with or without(Negative Control)the application of *** action potentials recorded immediately after PEG-fusion repair confirmed conduction across the injury *** success of PEG-fusion was confirmed through Sciatic Functional Index testing with PEG-fused animals showing improvement in locomotor function beginning at 35 days *** 2–42 days postoperatively,we anterogradely labeled sensory afferents from the dorsal aspect of the hindpaw following bilateral intradermal injection of wheat germ agglutinin conjugated horseradish ***-fusion repair reestablished axonal *** to unoperated animals,labeled sensory afferents ipsilateral to the injury in PEG-fused animals were found in the appropriate area of the dorsal horn,as well as inappropriate mediolateral and rostrocaudal ***,despite having intact peripheral nerves,similar reorganizations of labeled sensory afferents were also observed contralateral to the injury and repa

关键词： axotomy dorsal horn peripheral nerve injury plasticity polyethylene glycol(PEG) sciatic nerve sensory terminals wheat germ agglutinin horseradish peroxidase

A proton birdcage coil integrated with interchangeable single loops for multi-nuclear MrI/MrS

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2024年第2期25卷 168-180页

作者： Yi ZHANG Zhiyan QUAN Feiyang LOU Yujiao FANG Garth J.thompson Gao CHEN Xiaotong ZHANG Department of Neurosurgery the Second Affiliated HospitalSchool of MedicineZhejiang UniversityHangzhou310009China Key Laboratory of Precise Treatment and Clinical Translational research of Neurological Diseases Hangzhou310009China MOE Frontier Science Center for Brain Science and Brain-machine Integration Zhejiang UniversityHangzhou310058China Interdisciplinary Institute of Neuroscience and Technology College of Biomedical Engineering&Instrument ScienceZhejiang UniversityHangzhou310027China School of Medicine Zhejiang UniversityHangzhou310020China iHuman Institute School of Life Science and TechnologyShanghaiTech UniversityShanghai201210China College of Electrical Engineering Zhejiang UniversityHangzhou310027China

Energy metabolism is fundamental for *** encompasses the utilization of carbohydrates,lipids,and proteins for internal processes,while aberrant energy metabolism is implicated in many *** the present study,using three-dimensional(3D)printing from polycarbonate via fused deposition modeling,we propose a multi-nuclear radiofrequency(rF)coil design with integrated 1H birdcage and interchangeable X-nuclei(^(2)H,^(13)C,^(23)Na,and^(31)P)single-loop coils for magnetic resonance imaging(MrI)/magnetic resonance spectroscopy(MrS).The single-loop coil for each nucleus attaches to an arc bracket that slides unrestrictedly along the birdcage coil inner surface,enabling convenient switching among various nuclei and animal *** to a commercial 1H birdcage coil,the proposed 1H birdcage coil exhibited superior signal-excitation homogeneity and imaging signal-to-noise ratio(SNr).For X-nuclei study,prominent peaks in spectroscopy for phantom solutions showed excellent SNr,and the static and dynamic peaks of in vivo spectroscopy validated the efficacy of the coil design in structural imaging and energy metabolism detection simultaneously.

关键词： Energy metabolism Magnetic resonance imaging(MrI) Magnetic resonance spectroscopy(MrS) Multi-nuclear radiofrequency coil Three-dimensional(3D)printing

robotic-assisted versus laparoscopic repair of type II, III and IV hiatal hernias: A retrospective study comparing adverse outcomes

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Laparoscopic, Endoscopic and robotic Surgery 2024年第1期7卷 11-15页

作者： Payton Kooiker Shane Monnett Stephanie thompson Bryan richmond West Virginia School of Osteopathic Medicine LewisburgWV24901United States Department of Surgery Charleston Area Medical CenterCharlestonWV25304United States

Objective:robotic-assisted surgery(rAS)is continuing to expand in use in surgical specialties,including foregut *** available data on its use in large hiatal hernia(HH)repair are limited and *** study sought to determine whether there are significant differences in adverse outcomes following HH repair performed with a robotic approach vs.a laparoscopic *** study was limited to outcomes in patients with type II,III,and IV HHs,as these hernias are typically more challenging to ***:A retrospective analysis was performed from data obtained from TriNetX,a large deidentified clinical database,over a 10-year *** patients who underwent type II,III,or IV HH repair were included in the *** with robotic repair was compared to laparoscopic *** were propensity score matched for demographic information and *** ratios,risk differences(rDs)with 95%confidence intervals(CIs),and t test for each examined adverse outcome were used to estimate the effects of robotic repair *** ***:In total,20,016 patients who met the inclusion criteria were identified;1,515 patients utilized rAS,and 18,501 used *** to matching,there were significant differences in age,sex,comorbidity,and BMI between the two *** 1:1 propensity score matching,analyses of 1,514 well-matched patient pairs revealed no significant differences in demographics or *** who underwent robotic repair were more likely to experience major complications,including venous thromboembolism(rD:0.007,95%CI:0.003,0.011;p?0.002),critical care(rD:0.023,95%CI:0.007,0.039;p?0.004),urinary/renal complications(rD:0.027,95%CI:0.014,0.041;prespiratory complications(rD:0.046,95%CI:0.028,0.064;prAS was associated with a significantly shorter length of stay(32.4±27.5 h vs.35.7±50.1 h,p?0.031),although this finding indicated a reduction in the length of stay of less than 4 *** statist

关键词： Hiatal hernia robotic-assisted surgery Laparoscopic surgery Adverse outcomes

reduction of epinephrine in the lumbar spinal cord following repetitive blast-induced traumatic brain injury in rats

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Neural regeneration research 2024年第7期19卷 1548-1552页

作者： Shigeharu Tsuda Mustafa Golam Jiamei Hou Kevin K.W.Wang Floyd J.thompson Prodip Bose Brain rehabilitation research Center Malcom Randall VA Medical CenterNorth Florida/South Georgia Veterans Health SystemGainesvilleFLUSA Department of Anesthesiology College of MedicineUniversity of FloridaGainesvilleFLUSA Department of Emergency Medicine University of FloridaGainesvilleFLUSA Department of Neuroscience University of FloridaGainesvilleFLUSA Department of Neurology University of FloridaGainesvilleFLUSA

Traumatic brain inju ry-induced unfavorable outcomes in human patients have independently been associated with dysregulated levels of monoamines,especially epinephrine,although few preclinical studies have examined the epinephrine level in the central nervous system after traumatic brain *** has been shown to regulate the activities of spinal motoneurons as well as increase the heart rate,blood pressure,and blood flow to the hindlimb ***,the purpose of the present study was to determine the impact of repeated blast-induced traumatic brain injury on the epinephrine levels in seve ral function-s pecific central nervous system regions in *** three repeated blast injuries at 3-day intervals,the hippocampus,motor cortex,locus coeruleus,vestibular nuclei,and lumbar spinal cord were harvested at post-injury day eight and processed for epinephrine assays using a high-sensitive electrochemical detector cou pled with high-performance liquid *** results showed that the epinephrine levels were significantly decreased in the lumbar spinal cord tissues of blast-induced traumatic brain injury animals compared to the levels detected in age-and sex-matched sham *** other function-specific central nervous system regions,although the epinephrine levels were slightly altered following blast-induced tra u matic brain injury,they were not statistically *** results suggest that blast injury-induced significant downregulation of epinephrine in the lumbar spinal cord could negatively impact the motor and cardiovascular *** is the first repo rt to show altered epinephrine levels in the spinal cord following repetitive mild blast-induced traumatic brain injury.

关键词： balance blood flow cardiovascular system central nervous system epinephrine ischemic damage lumbar spinal cord muscle tone repeated blast spasticity traumatic brain injury

Design,Synthesis,and Applications of Mesoporous Covalent Organic Frameworks

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CCS Chemistry 2024年第1期6卷 57-68页

作者： Niyati Arora Cassandra Flores Milinda C.Senarathna Christina M.thompson ronald A.Smaldone Department of Chemistry and Biochemistry University of TexasDallasRichardsonTexas 75080

Covalent organic frameworks(COFs)are highly ordered and permanently porous organic polymers that can be classified as two-dimensional or *** tunable design and crystalline order endow a range of pore sizes,shapes,functions,and applications that differentiate them from other *** COF pore sizes and shapes rely on the geometry of the monomers and dynamic covalent chemistry,while the stacking of the sheets relies on noncovalent *** tunability allows for post-modification or the incorporation of additional functional groups for the reinforcement by various noncovalent *** limits of mesoporous COFs are still being investigated,with the design rules continuing to *** we report a comprehensive review of mesoporous COFs,explore strategies for large pore reinforcement,highlight structural design and features,elucidate their various functions and applications,discuss fundamental challenges faced that need to be addressed,and predict future directions.

关键词： covalent organic frameworks mesoporous supramolecular chemistry polymers pore size

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Happy Bird

小学生时代（大嘴英语） 2024年第4期 18-20页

作者： Claudia Lee-Ottman Lindsay dale-Scott(图) 不详

Analysis and Optimization of Operational and Pollutant Attributes of Diesel Engine with CNT-Infused Orange Peel Biodiesel-Diesel Blend Fuel

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Journal of Thermal Science 2024年第2期33卷 761-778页

作者： ranjeet rAI r.r.SAHOO Mechanical Engineering Department GLA UniversityMathura281406India Mechanical Engineering Department IIT(BHU)Varanasi221005India

The current study is performed to find sustainable solutions for the future of transportation and environmental *** conventional methods and experimental design table(L16 Orthogonal Array)techniques have been employed to examine and optimize a diesel-powered engine's operational and pollutant *** L16 Orthogonal Array is obtained through Taguchi's experimental design approach using Minitab 16 *** experimental design incorporated three control variables,namely engine speed,fuel type,and engine load,each with four *** operational parameters,namely brake thermal efficiency(BTE)and brake specific fuel consumption(BSFC),as well as the emission characteristics,including hydrocarbon(HC),carbon monoxide(CO),nitrogen oxide(NO),and smoke emissions,were acquired using the L16 orthogonal array(OA) and subsequently *** utilization of methodologies such as signal-to-noise(S/N) ratio and grey analysis was employed to determine the optimal operational state of the engine to achieve maximum performance while minimizing *** engine's ideal state of operation,in terms of BTE and BSFC,was determined to be at 75% engine load,1000 r/min engine speed,and using 10^(-4)(in vol) carbon nanotube incorporated 20% orange peel biodiesel(OPB20CNT100) blended fuel(A3-B1-C4).The study indicated that engine load significantly influenced BTE and BSFC,with 84.05% and 87.79% contribution factors,*** 25% engine load,1000 r/min,and OPB20CNT100 fuel(A1-B1-C4) CO,smoke,NO,and HC emissions were the *** load affects emissions the *** BSFC increased 3.10% and NO emissions 1.77%.BTE,CO,smoke,and HC emissions decreased by 1.9%,12.29%,47.05%,and 47.22%,respectively,at optimal operating conditions concerning diesel *** study shows that Taguchi-Grey's experimental design optimizes diesel engine operational and pollutant *** outcomes revealed that orange peel biodiesel infused with CNT can replace diesel fuel in a

关键词： Taguchi-Grey method OPB20CNT100 transesterification S/N ratio GrG HC CO and NO

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轨道车辆一系螺旋弹簧振动疲劳失效分析

振动与冲击 2024年第1期43卷 230-236页

作者：孙文静王嘉豪 thompson David 王腾飞周劲松同济大学铁道与城市轨道交通研究院上海201804 Institute of Sound and Vibration research University of SouthamptonSouthampton SO171BJUK

轨道车辆服役工况下一系悬挂系统中的金属螺旋弹簧疲劳断裂时有发生,影响列车运行安全性。针对某一系螺旋弹簧疲劳失效故障,考虑轮轨激励与弹簧结构动态特性耦合关系,建立准确提取弹簧载荷的模型,通过结构频域疲劳分析法计算弹簧动应力... 详细信息

轨道车辆服役工况下一系悬挂系统中的金属螺旋弹簧疲劳断裂时有发生,影响列车运行安全性。针对某一系螺旋弹簧疲劳失效故障,考虑轮轨激励与弹簧结构动态特性耦合关系,建立准确提取弹簧载荷的模型,通过结构频域疲劳分析法计算弹簧动应力响应与疲劳寿命。首先考虑螺旋弹簧结构的动态特性,建立包含一系动刚度特性的车辆-轨道耦合精细化动力学模型,然后在轮轨激励下提取服役工况弹簧两端动载荷,最后采用结构频域疲劳分析法计算弹簧动应力响应与疲劳寿命,并与实测动应力结果进行对比验证。结果表明:螺旋弹簧自身动态特性体现在:多阶模态频率下弹簧中部的最大模态变形与簧条1~2圈间的最大模态应力;基于耦合动力学模型,计算得到内簧动应力响应与实测结果一致,在58 Hz的动应力峰值是其它频率动应力峰值的3倍以上;由于内簧一阶固有频率与轮轨系统P2共振频率接近,弹簧内部共振引起簧条1.2圈内侧高应力,该处疲劳寿命最短的分析结果与现场断裂位置吻合,而外簧的最短疲劳寿命约为内簧的3.6倍。因此,同时考虑轮轨激励与螺旋弹簧自身动态特性,使得一系螺旋弹簧固有频率远离轮轨共振频率,可提高弹簧结构的抗疲劳特性。

关键词：轨道车辆螺旋弹簧模态频率动应力振动疲劳