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  • 简介:ThiscommentaryisbasedontheworkofCooper,Davis,andVanVliet(2016)andthecommentaryfocusesonwhatproblemhigh-frequencytradingposes.Itlistskeyliteratureonhigh-frequencytradingthatismissingandpointsoutthatthepokeranalogytodefenddeceptioninfinancialmarketsisweakandmisleading.Thearticleelaboratesonthenegativeimpactcreatedbyspoofingandquotestuffing,thetwotypicaldeceptivepracticesusedbyhigh-frequencytraders.Therecentregulationsregardinghigh-frequencytrading,inresponsetothe“FlashCrash”of2010,arepreventive,computerizedandmoreeffective.Theyreflectethicalrequirementstomaintainfairandstablefinancialmarkets.

  • 标签: HIGH-FREQUENCY TRADING DECEPTION VOLATILITY INSTABILITY ETHICS
  • 简介:High-frequencyimagetechniquehasbeenwidelyappliedinmedicaldiagnosisrecently.Forhighvoltageprotection,highspeedstageandtriggercontrolcircuitryaredifficulttoimplementahigh-frequencyultrasoundimagingsystem.Inthisstudy,weutilizedalinearservowithhighnoisetoleranceandanovelmulti-depthexpressionmethodtoovercomethoseissuesindevelopedhigh-speedimagesystem.B-modeimageofthechickenphantomby25MHztransducershowstheresolutionoflateralandaxialresolutionsareupto123μmand59μmrespectively.Inaddition,theexperimentdemonstratesthattheaxialresolutionanddepthoffield(DOF)canbeimprovedbytimegaincompensation(TGC)andmulti-depthmethod.Theresultsindicatethattheproposedsystemcouldachieveover24fpsfor1mmscandistanceand100linesperframe.Inthefuture,thedevelopedsystemispotentialforotherclinicalapplicationssuchasophthalmologyanddermatology.

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  • 简介:与大约2个小时的时期,高周波的摆动被把小浪分析用于首先识别详细地绕热带气旋(TC)的眼睛和eyewall观察了风速度。台风Hagupit(2008)的模型模拟的分析证明摆动也在eyewall附近发生在TC紧张,垂直运动,集中活动和空气密度。在这些变量的摆动的序列跟随某个顺序。

  • 标签: 高频振荡 热带气旋 识别 小波分析 模型仿真 垂直运动
  • 简介:WeestablishasystemtomeasurethefunctionalabsorptioncrosssectionofphotosystemII(PSII)(σPSII)andmaximumquantumyieldofphotochemistryinPSII(Fv/Fm).Thesystemutilizesasequenceofhighfrequencyexcitationflashesatmicrosecondintervalstoinduceamicrosecond-levelfluorescenceyieldcurve.ParametersσPSIIandFv/Fmarecalculatedbyfittingthecurveusingnonlinearregression.Experimentalresultsshowthattherelativestandarddeviation(RSD)ofthesystemislessthan3%,andthecorrelationcoefficientofFv/Fmvaluesmeasuredbythissystemandthosemeasuredbypulseamplitudemodulationmethodis0.950.

  • 标签: PSII 参数测量 高频激励 光合 闪烁 藻类
  • 简介:Variouscosmologymodels,braneoscillationscenarios,interactionofinterstellarplasmawithintenseelectromagneticradiation,andevenhigh-energyphysicsexperiments(e.g.,LargeHadronCollider(LHC))allpredicthighfrequencygravitationalwaves(HFGWs,i.e.,high-energygravitons)inthemicrowavebandandhigherfrequencyregion,andsomeofthemhavelargeenergydensities.Electromagnetic(EM)detectiontosuchHFGWswouldbesuitableduetoveryhighfrequenciesandlargeenergydensitiesoftheHFGWs.WereviewseveraltypicalEMdetectionschemes,i.e.,inverseGertsenshteineffect(G-effect),couplingoftheinverseGeffectwithacoherentEMwave,couplingofplanarsuperconductingopencavitywithastaticmagneticfield,cylindricalsuperconductingclosedcavity,andtheEMsychro-resonancesystem,anddiscussrelatedminimaldetectableamplitudesandsensitivities.Furthermore,wegivesomenewideasandimprovementwaysenhancingthepossibilityofmeasuringtheHFGWs.ItisshownthatthereisstillalargeroomforimprovementforthoseschemestoapproachandevenreachuptherequirementofdetectionofHFGWsexpectedbythecosmologicalmodelsandhigh-energyastrophysicalprocess.

  • 标签: 高频引力波 电磁响应 谱密度 大型强子对撞机 宇宙学模型 能量密度
  • 简介:高周波的电磁的发出声音作为地来源是用自然的高周波的电磁的地的一个电磁的探索方法。它比直接当前的方法有更高的分辨率和更大的深度穿入并且为地热的精力探索是特别合适的并且低--并且中间水平的地下水察觉。我们介绍为评估地热的水资源的高周波的电磁的发出声音的成功的应用。高频率电磁的系统(有到1Hz的从10KHz的一个频率范围的MT-U5A)首先被使用从中国取样域数据。一个遥远的参考车站被用来保证取样的数据质量。我们然后执行2D倒置图象与电的方法数据处理。结果基本上显示地下的地热的水的空间分发并且提供有利线索给在这个区域发现表面下的地热的水的来源。

  • 标签: 电磁 地热学 温泉 探测方法
  • 简介:Severevibrationofundergroundstructuresmaybeinducedunderblastloads.Accordingtothecharacteristicsoftheexplosion-inducedgroundshockwave,anew-typedamper,inversecontrolmagneto-rheological(MR)damperwasdesignedtocontrolthevibration.Thehigh-frequencyperformancetestoftheMRdamperwascarriedoutonthesmallshakingtable.ItisshownthattheperformancecanbemodeledbyuseofthemodifiedBouc-Wenmodel,andtheparametersofthemodelkeepstableintheranqeof15-50Hz.

  • 标签: 建筑结构 反向控制磁电机流变阻尼器 高频率波 振动描述 性能试验
  • 简介:AbstractBackground:The combination of high-frequency oscillations (HFOs) with single-mode imaging methods has been proved useful in identifying epileptogenic zones, whereas few studies have examined HFOs combined with multimodal imaging methods. The aim of this study was to evaluate the prognostic value of ripples, an HFO subtype with a frequency of 80 to 200 Hz is combined with multimodal imaging methods in predicting epilepsy surgery outcome.Methods:HFOs were analyzed in 21 consecutive medically refractory epilepsy patients who underwent epilepsy surgery. All patients underwent positron emission tomography (PET) and deep electrode implantation for stereo-electroencephalography (SEEG); 11 patients underwent magnetoencephalography (MEG). Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy in predicting surgical outcome were calculated for ripples combined with PET, MEG, both PET and MEG, and PET combined with MEG. Kaplan-Meier survival analyses were conducted in each group to estimate prognostic value.Results:The study included 13 men and 8 women. Accuracy for ripples, PET, and MEG alone in predicting surgical outcome was 42.9%, 42.9%, and 81.8%, respectively. Accuracy for ripples combined with PET and MEG was the highest. Resection of regions identified by ripples, MEG dipoles, and combined PET findings was significantly associated with better surgical outcome (P < 0.05).Conclusions:Intracranial electrodes are essential to detect regions which generate ripples and to remove these areas which indicate good surgical outcome for medically intractable epilepsy. With the assistance of presurgical noninvasive imaging examinations, PET and MEG, for example, the SEEG electrodes would identify epileptogenic regions more effectively.

  • 标签: High-frequency oscillations Ripples PET MEG Epileptogenic zone
  • 简介:高周波的表面波浪雷达(HFSWR)和自动鉴定系统(AIS)是使用容器追踪的二个很重要的传感器。HFSWR能被用于在一个察觉区域追踪所有容器,当AIS通常被用来验证合作容器的信息时。因为从海喧嚷的干扰,为容器追踪采用单个频率的HFSWR可以遮住位于布拉格山峰的盲目地区的容器。在察觉频率分析变化为探讨这缺乏组成一个有效方法。由容器熔化追踪组成的一个解决方案用AIS校准的双频率的HFSWR数据被建议。因为不同系统的偏爱在HFSWR频率大小和AIS大小之间存在,AIS信息被用来估计并且改正HFSWR在每频率的系统的偏爱。首先,为合作容器的AIS点大小用一个日本胜利公司任务算法与HFSWR大小被联系。从合作容器的协会结果,在dualfrequencyHFSWR数据的系统的偏爱被估计并且改正。基于改正的双频率的HFSWR数据,然后,容器用一个双频率的熔化关节被追踪概率的数据协会(JPDA)-unscentedKalman过滤器(UKF)算法。用真实察觉数据的试验性的结果证明建议方法在在实时追踪容器是有效的并且能与追踪包含单个频率的数据的过程相比改进追踪的能力和精确性。

  • 标签: 自动鉴定系统 表面波浪 双频率 高周波 容器 追踪
  • 简介:摘要ObjectiveThe present study aimed to investigate the effects of rTMS on astrocytic polarization during cerebral ischemic/reperfusion injury.MethodsThree rTMS protocols were applied to primary astrocytes under normal and oxygen-glucose deprivation/reoxygenation (OGD/R) conditions. Cell survival, proliferation, and phenotypic changes were assessed after 2-day treatment. Astrocytes culture medium (ACM) from control, OGD/R, and OGD/R + rTMS groups were mixed with neuronal medium to culture neurons for 48 h and 7 days, in order to explore the influence on neuronal survival and synaptic plasticity. In vivo, rats were subjected to middle cerebral artery occlusion (MCAO), and received posterior orbital intravenous injection of ACM collected from different groups at reperfusion, and at 3 days post reperfusion. The apoptosis in the ischemic penumbra, infarct volumes, and the modified Neurological Severity Score (mNSS) were evaluated at 1 week after reperfusion, and cognitive functions were evaluated using the Morris Water Maze (MWM) tests. Finally, the 10 Hz rTMS was directly applied to MCAO rats to verify the rTMS effects on astrocytic polarizationResultsAmong these three frequencies, the 10 Hz protocol exerted the greatest potential to modulate astrocytic polarization after OGD/R injury. Classically activated and A1 markers were significantly inhibited by rTMS treatment. In OGD/R model, the concentration of pro-inflammatory mediator TNF-α decreased from 57.7 to 23.0 pg/mL, while anti-inflammatory mediator IL-10 increased from 99.0 to 555.1 pg/mL in the ACM after rTMS treatment. The ACM collected from rTMS-treated astrocytes significantly alleviated neuronal apoptosis induced by OGD/R injury, and promoted neuronal plasticity. In MCAO rat model, the ACM collected from rTMS treatment decreased neuronal apoptosis and infarct volumes, and improved cognitive functions. The neurotoxic astrocytes were simultaneously inhibited after rTMS treatment.ConclusionsInhibition of neurotoxic astrocytic polarization is a potential mechanism for the effectiveness of high-frequency rTMS in cerebral ischemic stroke.

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  • 简介:摘要ObjectiveBecause the reliability of repetitive transcranial magnetic stimulation (rTMS) in treating poststroke cognitive impairment has not been convincingly demonstrated, we systematically examined the effectiveness of this regimen with 2 protocols.MethodsWe randomly allocated 41 patients with poststroke cognitive impairment to receive 5 Hz rTMS (n=11), intermittent theta burst stimulation (iTBS; n=15) or sham stimulation (n=15). Each group received 10 stimulation sessions over the left dorsolateral prefrontal cortex. We performed the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and the Beck Depression Inventory at baseline and after the intervention.ResultsThe 5 Hz rTMS group showed significantly greater improvement than the sham group in RBANS total score (P=0.006), attention (P=0.001) and delayed memory (P<0.001). The iTBS group showed significantly greater improvement than the sham group in RBANS total score (P=0.005) and delayed memory (P=0.007). The 5 Hz rTMS group exhibited a superior modulating effect in attention compared to the iTBS group (P=0.016). Patients without comorbid hypertension (P=0.008) were predisposed to favourable therapeutic outcomes.ConclusionsOur results demonstrated that both 5 Hz rTMS and iTBS were effective for poststroke cognitive impairment in terms of global cognition, attention and memory function; the domain of attention was susceptible to 5 Hz modulation. Treatment with 5 Hz rTMS may slow cognitive decline, representing both a pivotal process in poststroke cognitive impairment and an aspect of neuroplasticity that contributes to disease-modifying strategies.

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  • 简介:摘要ObjectiveThis study aimed to evaluate the effect of different combinations of rTMS and cognitive training (rTMS-COG) on PSCI and identify the optimal combination protocol.MethodsA cerebral infarction rat model was established by transient middle cerebral artery occlusion (tMCAO). The Morris water maze test was conducted to assess the cognitive function of rats. RNA sequencing and bioinformatics analysis were employed to study the underlying mechanisms.ResultsrTMS, COG and rTMS-COG all had beneficial effects on PSCI, while cognitive training immediately after rTMS (rTMS-COG0h) achieved a better effect than cognitive training 1 h and 4 h after rTMS, rTMS and COG. We identified 179 differentially expressed genes (DEGs), including 24 upregulated and 155 downregulated genes, between the rTMS-COG0h and rTMS groups. GO analysis revealed that the major categories associated with the DEGs were antigen procession and presentation, regulation of protein phosphorylation and axoneme assembly. KEGG analysis showed that the DEGs were enriched in processes related to phagosome, circadian entrainment, dopaminergic synapse, apelin signaling pathway, long-term depression, neuroactive ligand-receptor interaction, axon guidance and glucagon signaling pathway. PPI analysis identified Calb2, Rsph1, Ccdc114, Acta2, Ttll9, Dnah1, Dlx2, Dlx1, Ccdc40 and Ccdc113 as related genes.ConclusionsThese findings prompt exploration of the potential mechanisms and key genes involved in the effect of rTMS-COG0h on PSCI.

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  • 简介:nano石墨表/氧化铝composites被一个灵巧的受精减小过程在situ准备。composites的微观结构被X光检查衍射(XRD)分析,并且在减小以后的最后的阶段作文是艾尔2O3,金属Fe和石墨水晶。扫描电子显微镜学(SEM)图象证明Fe的粒子尺寸是大约20?nm,和石墨的lamellae厚度是大约30?nm。然后,绝缘的性质和composites的传导性的机制在0.01-1.00的频率范围试验性地被调查?由阻抗分析器的GHz。composites的介电常数的真实部分与Fe3+集中增加的结果表演,由于在Fe和艾尔23和薄片状的石墨形成的三维的网络。因此,悦耳的microtopography和nano石墨表/氧化铝composites的电的参数能被改变Fe3+集中认识到。

  • 标签: 铝复合材料 浸渍还原法 纳米石墨 介电性能 氧化铝 制备
  • 简介:Brief-pulsestimulationat50Hzhasbeenshowntoterminateafterdischargesobservedinepilepsypatients.However,theoptimalpulsestimulationparametersforterminatingcorticalelectricalstimulation-inducedafterdischargesremainunclear.Inthepresentstudy,weexaminedtheeffectsofdifferentbrief-pulsestimulationfrequencies(5,50and100Hz)oncorticalelectricalstimulation-inducedafterdischargesin10patientswithrefractoryepilepsy.Resultsdemonstratedthatbrief-pulsestimulationcouldterminatecorticalelectricalstimulation-inducedafterdischargesinrefractoryepilepsypatients.Inconclusion,(1)abrief-pulsestimulationwasmoreeffectivewhentheafterdischargedidnotextendtothesurroundingbrainarea.(2)Ahigherbrief-pulsestimulationfrequency(especially100Hz)wasmorelikelytoterminateanafterdischarge.(3)Alowcurrentintensityofbrief-pulsestimulationwasmorelikelytoterminateanafterdischarge.

  • 标签: 短脉冲 电刺激 高频率 诱导 皮质 电流强度
  • 简介:BSTOdielectricceramicwaspreparedfromSrTiO3andBaTiO3powderssynthesizedbyhydrothermalmethod,aswellasfromBa0.6Sr0.4TiO3powdersynthesizedbyconventionalsolid-statereaction.Theformercanbesinteredatarelativelylowtemperatureof1120℃.CharacterizationbySEMshowedthatthegrainshapesofbothceramicsarecubical,thoughthegrainsizeoftheformerismuchsmaller.Dielectricconstantsmeasuredat20℃wereshowntovarywithfrequencyintherangefrom1kHzto2MHzanddcbiasfield,andfurtherthatthedielectriclossoftheformertobelessthan2×10-3inthefrequencyrangeof20kHzto1MHz,muchsmallerthanthatofthelattersample.Fortheformer,temperaturedependenceofdielectricconstantismuchflatterandthereexistsanextendedphasetransitiondiffusioncoveringawidetemperaturerangeofCurietemperatureTc.Thesmallergrainsizeoftheformerdepressesthedcbiaselectricalfielddependenceofdielectricconstant.Thetunabilityis7%underabiasfieldof0.6kV/mmdc.

  • 标签: 钛酸锶钡陶瓷 钛酸钡粉体 介电性能 水热合成 介电常数测量 高频
  • 简介:Theoreticalanalysisoftheelectromagneticfielddistributioninthefocalregionofalongmetallicparabolicreflectorthathasitssurfacecoveredwithamagnetizedplasmalayerisderived.Theincidentwaveisconsideredtobewithageneralobliqueincidenceforbothparallelandperpendicularpolarizations.TheelectromagneticfieldintensityexpressionsalongthefocalregionareobtainedaccuratelyusingMaslov’smethod.Theeffectsofplasmathicknessonthereflectedandtransmittedfielddistributionsareinvestigated.Theeffectsofotherphysicalparameterssuchastheangleofincidenceandtheplasmaandcyclotronfrequenciesonthetransmittedfieldintensitydistributionalongthefocalregionarealsostudied.TheresultsobtainedbyMaslov’smethodandKirchhoff’sapproximationarefoundtobeinagoodagreement.

  • 标签: 光学 光本性 光折射 光反射
  • 简介:AbstractBackground:High-frequency irreversible electroporation (H-FIRE) is a novel, next-generation nanoknife technology with the advantage of relieving irreversible electroporation (IRE)-induced muscle contractions. However, the difference between IRE and H-FIRE with distinct ablation parameters was not clearly defined. This study aimed to compare the efficacy of the two treatments in vivo.Methods:Ten Bama miniature swine were divided into two group: five in the 1-day group and five in the 7-day group. The efficacy of IRE and H-FIRE ablation was compared by volume transfer constant (Krans), rate constant (Kep) and extravascular extracellular volume fraction (Ve) value of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), size of the ablation zone, and histologic analysis. Each animal underwent the IRE and H-FIRE. Temperatures of the electrodes were measured during ablation. DCE-MRI images were obtained 1, 4, and 7 days after ablation in the 7-day group. All animals in the two groups were euthanized 1 day or 7 days after ablation, and subsequently, IRE and H-FIRE treated liver tissues were collected for histological examination. Student’s t test or Mann-Whitney U test was applied for comparing any two groups. One-way analysis of variance (ANOVA) test and Welch’s ANOVA test followed by Holm-Sidak’s multiple comparisons test, one-way ANOVA with repeated measures followed by Bonferroni test, or Kruskal-Wallis H test followed by Dunn’s multiple comparison test was used for multiple group comparisons and post hoc analyses. Pearson correlation coefficient test was conducted to analyze the relationship between two variables.Results:Higher Ve was seen in IRE zone than in H-FIRE zone (0.14 ± 0.02 vs. 0.08 ± 0.05, t= 2.408, P = 0.043) on day 4, but no significant difference was seen in Ktrans or Kep between IRE and H-FIRE zones at all time points (all P > 0.05). For IRE zone, the greatest Ktrans was seen on day 7, which was significantly higher than that on day 1 (P = 0.033). The ablation zone size of H-FIRE was significantly larger than IRE 1 day (4.74 ± 0.88 cm2vs. 3.20 ± 0.77 cm2, t = 3.241, P = 0.009) and 4 days (2.22 ± 0.83 cm2vs. 1.30 ± 0.50 cm2, t = 2.343, P = 0.041) after treatment. Apoptotic index (0.05 ± 0.02 vs. 0.73 ± 0.06 vs. 0.68 ± 0.07, F = 241.300, P < 0.001) and heat shock protein 70 (HSP70) (0.03 ± 0.01 vs. 0.46 ± 0.09 vs. and 0.42 ± 0.07, F= 64.490, P < 0.001) were significantly different between the untreated, IRE and H-FIRE zones, but no significant difference was seen in apoptotic index or HSP70 between IRE and H-FIRE zone (both P > 0.05). Electrode temperature variations were not significantly different between the two zones (18.00 ± 3.77°C vs. 16.20 ± 7.45°C, t = 0.682, P = 0.504). The Ktrans value (r = 0.940, P = 0.017) and the Kep value (r = 0.895, P = 0.040) of the H-FIRE zone were positively correlated with the number of hepatocytes in the ablation zone.Conclusions:H-FIRE showed a comparable ablation effect to IRE. DCE-MRI has the potential to monitor the changes of H-FIRE ablation zone.

  • 标签: Irreversible electroporation High-frequency irreversible electroporation Dynamic contrast enhanced-magnetic resonance imaging Thermal damage